deps: update V8 to 5.7.492.69

PR-URL: https://github.com/nodejs/node/pull/11752
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Franziska Hinkelmann <franziska.hinkelmann@gmail.com>

27 files changed, 4582 insertions, 2291 deletions

diff --git a/deps/v8/src/wasm/OWNERS b/deps/v8/src/wasm/OWNERS
index 2822c29819..4f54661aeb 100644
--- a/deps/v8/src/wasm/OWNERS
+++ b/deps/v8/src/wasm/OWNERS
@@ -2,6 +2,7 @@ set noparent
 
 ahaas@chromium.org
 bradnelson@chromium.org
+clemensh@chromium.org
 mtrofin@chromium.org
 rossberg@chromium.org
 titzer@chromium.org
diff --git a/deps/v8/src/wasm/decoder.h b/deps/v8/src/wasm/decoder.h
index fc8f110b73..afe8701779 100644
--- a/deps/v8/src/wasm/decoder.h
+++ b/deps/v8/src/wasm/decoder.h
@@ -34,7 +34,12 @@ class Decoder {
   Decoder(const byte* start, const byte* end)
       : start_(start),
         pc_(start),
-        limit_(end),
+        end_(end),
+        error_pc_(nullptr),
+        error_pt_(nullptr) {}
+  Decoder(const byte* start, const byte* pc, const byte* end)
+      : start_(start),
+        pc_(pc),
         end_(end),
         error_pc_(nullptr),
         error_pt_(nullptr) {}
@@ -44,7 +49,7 @@ class Decoder {
   inline bool check(const byte* base, unsigned offset, unsigned length,
                     const char* msg) {
     DCHECK_GE(base, start_);
-    if ((base + offset + length) > limit_) {
+    if ((base + offset + length) > end_) {
       error(base, base + offset, "%s", msg);
       return false;
     }
@@ -185,22 +190,27 @@ class Decoder {
 
   // Consume {size} bytes and send them to the bit bucket, advancing {pc_}.
   void consume_bytes(uint32_t size, const char* name = "skip") {
-    TRACE("  +%d  %-20s: %d bytes\n", static_cast<int>(pc_ - start_), name,
-          size);
+#if DEBUG
+    if (name) {
+      // Only trace if the name is not null.
+      TRACE("  +%d  %-20s: %d bytes\n", static_cast<int>(pc_ - start_), name,
+            size);
+    }
+#endif
     if (checkAvailable(size)) {
       pc_ += size;
     } else {
-      pc_ = limit_;
+      pc_ = end_;
     }
   }
 
-  // Check that at least {size} bytes exist between {pc_} and {limit_}.
+  // Check that at least {size} bytes exist between {pc_} and {end_}.
   bool checkAvailable(int size) {
     intptr_t pc_overflow_value = std::numeric_limits<intptr_t>::max() - size;
     if (size < 0 || (intptr_t)pc_ > pc_overflow_value) {
       error(pc_, nullptr, "reading %d bytes would underflow/overflow", size);
       return false;
-    } else if (pc_ < start_ || limit_ < (pc_ + size)) {
+    } else if (pc_ < start_ || end_ < (pc_ + size)) {
       error(pc_, nullptr, "expected %d bytes, fell off end", size);
       return false;
     } else {
@@ -241,11 +251,11 @@ class Decoder {
   template <typename T>
   T traceOffEnd() {
     T t = 0;
-    for (const byte* ptr = pc_; ptr < limit_; ptr++) {
+    for (const byte* ptr = pc_; ptr < end_; ptr++) {
       TRACE("%02x ", *ptr);
     }
     TRACE("<end>\n");
-    pc_ = limit_;
+    pc_ = end_;
     return t;
   }
 
@@ -272,7 +282,6 @@ class Decoder {
   void Reset(const byte* start, const byte* end) {
     start_ = start;
     pc_ = start;
-    limit_ = end;
     end_ = end;
     error_pc_ = nullptr;
     error_pt_ = nullptr;
@@ -281,16 +290,16 @@ class Decoder {
 
   bool ok() const { return error_msg_ == nullptr; }
   bool failed() const { return !ok(); }
-  bool more() const { return pc_ < limit_; }
+  bool more() const { return pc_ < end_; }
 
-  const byte* start() { return start_; }
-  const byte* pc() { return pc_; }
-  uint32_t pc_offset() { return static_cast<uint32_t>(pc_ - start_); }
+  const byte* start() const { return start_; }
+  const byte* pc() const { return pc_; }
+  uint32_t pc_offset() const { return static_cast<uint32_t>(pc_ - start_); }
+  const byte* end() const { return end_; }
 
  protected:
   const byte* start_;
   const byte* pc_;
-  const byte* limit_;
   const byte* end_;
   const byte* error_pc_;
   const byte* error_pt_;
@@ -308,7 +317,7 @@ class Decoder {
     const int kMaxLength = (sizeof(IntType) * 8 + 6) / 7;
     const byte* ptr = base + offset;
     const byte* end = ptr + kMaxLength;
-    if (end > limit_) end = limit_;
+    if (end > end_) end = end_;
     int shift = 0;
     byte b = 0;
     IntType result = 0;
@@ -358,7 +367,7 @@ class Decoder {
       const int kMaxLength = (sizeof(IntType) * 8 + 6) / 7;
       const byte* pos = pc_;
       const byte* end = pc_ + kMaxLength;
-      if (end > limit_) end = limit_;
+      if (end > end_) end = end_;
 
       IntType result = 0;
       int shift = 0;
diff --git a/deps/v8/src/wasm/ast-decoder.cc b/deps/v8/src/wasm/function-body-decoder.cc
index ff6af34a02..04a2806237 100644
--- a/deps/v8/src/wasm/ast-decoder.cc
+++ b/deps/v8/src/wasm/function-body-decoder.cc
@@ -9,8 +9,8 @@
 #include "src/handles.h"
 #include "src/zone/zone-containers.h"
 
-#include "src/wasm/ast-decoder.h"
 #include "src/wasm/decoder.h"
+#include "src/wasm/function-body-decoder.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-opcodes.h"
 
@@ -31,16 +31,14 @@ namespace wasm {
 #define TRACE(...)
 #endif
 
-#define CHECK_PROTOTYPE_OPCODE(flag)                   \
-  if (module_ && module_->origin == kAsmJsOrigin) {    \
-    error("Opcode not supported for asmjs modules");   \
-  }                                                    \
-  if (!FLAG_##flag) {                                  \
-    error("Invalid opcode (enable with --" #flag ")"); \
-    break;                                             \
+#define CHECK_PROTOTYPE_OPCODE(flag)                           \
+  if (module_ != nullptr && module_->origin == kAsmJsOrigin) { \
+    error("Opcode not supported for asmjs modules");           \
+  }                                                            \
+  if (!FLAG_##flag) {                                          \
+    error("Invalid opcode (enable with --" #flag ")");         \
+    break;                                                     \
   }
-// TODO(titzer): this is only for intermediate migration.
-#define IMPLICIT_FUNCTION_END 1
 
 // An SsaEnv environment carries the current local variable renaming
 // as well as the current effect and control dependency in the TF graph.
@@ -70,7 +68,7 @@ struct SsaEnv {
 struct Value {
   const byte* pc;
   TFNode* node;
-  LocalType type;
+  ValueType type;
 };
 
 struct TryInfo : public ZoneObject {
@@ -87,9 +85,9 @@ struct MergeValues {
     Value first;
   } vals;  // Either multiple values or a single value.
 
-  Value& first() {
-    DCHECK_GT(arity, 0u);
-    return arity == 1 ? vals.first : vals.array[0];
+  Value& operator[](size_t i) {
+    DCHECK_GT(arity, i);
+    return arity == 1 ? vals.first : vals.array[i];
   }
 };
 
@@ -101,11 +99,12 @@ enum ControlKind { kControlIf, kControlBlock, kControlLoop, kControlTry };
 struct Control {
   const byte* pc;
   ControlKind kind;
-  int stack_depth;    // stack height at the beginning of the construct.
-  SsaEnv* end_env;    // end environment for the construct.
-  SsaEnv* false_env;  // false environment (only for if).
-  TryInfo* try_info;  // Information used for compiling try statements.
+  size_t stack_depth;      // stack height at the beginning of the construct.
+  SsaEnv* end_env;         // end environment for the construct.
+  SsaEnv* false_env;       // false environment (only for if).
+  TryInfo* try_info;       // Information used for compiling try statements.
   int32_t previous_catch;  // The previous Control (on the stack) with a catch.
+  bool unreachable;        // The current block has been ended.
 
   // Values merged into the end of this control construct.
   MergeValues merge;
@@ -116,30 +115,30 @@ struct Control {
   inline bool is_try() const { return kind == kControlTry; }
 
   // Named constructors.
-  static Control Block(const byte* pc, int stack_depth, SsaEnv* end_env,
+  static Control Block(const byte* pc, size_t stack_depth, SsaEnv* end_env,
                        int32_t previous_catch) {
-    return {pc,      kControlBlock, stack_depth,    end_env,
-            nullptr, nullptr,       previous_catch, {0, {NO_VALUE}}};
+    return {pc,      kControlBlock,  stack_depth, end_env,        nullptr,
+            nullptr, previous_catch, false,       {0, {NO_VALUE}}};
   }
 
-  static Control If(const byte* pc, int stack_depth, SsaEnv* end_env,
+  static Control If(const byte* pc, size_t stack_depth, SsaEnv* end_env,
                     SsaEnv* false_env, int32_t previous_catch) {
-    return {pc,        kControlIf, stack_depth,    end_env,
-            false_env, nullptr,    previous_catch, {0, {NO_VALUE}}};
+    return {pc,      kControlIf,     stack_depth, end_env,        false_env,
+            nullptr, previous_catch, false,       {0, {NO_VALUE}}};
   }
 
-  static Control Loop(const byte* pc, int stack_depth, SsaEnv* end_env,
+  static Control Loop(const byte* pc, size_t stack_depth, SsaEnv* end_env,
                       int32_t previous_catch) {
-    return {pc,      kControlLoop, stack_depth,    end_env,
-            nullptr, nullptr,      previous_catch, {0, {NO_VALUE}}};
+    return {pc,      kControlLoop,   stack_depth, end_env,        nullptr,
+            nullptr, previous_catch, false,       {0, {NO_VALUE}}};
   }
 
-  static Control Try(const byte* pc, int stack_depth, SsaEnv* end_env,
+  static Control Try(const byte* pc, size_t stack_depth, SsaEnv* end_env,
                      Zone* zone, SsaEnv* catch_env, int32_t previous_catch) {
     DCHECK_NOT_NULL(catch_env);
     TryInfo* try_info = new (zone) TryInfo(catch_env);
-    return {pc,      kControlTry, stack_depth,    end_env,
-            nullptr, try_info,    previous_catch, {0, {NO_VALUE}}};
+    return {pc,       kControlTry,    stack_depth, end_env,        nullptr,
+            try_info, previous_catch, false,       {0, {NO_VALUE}}};
   }
 };
 
@@ -164,24 +163,123 @@ struct LaneOperand {
 // lengths, etc.
 class WasmDecoder : public Decoder {
  public:
-  WasmDecoder(ModuleEnv* module, FunctionSig* sig, const byte* start,
+  WasmDecoder(const WasmModule* module, FunctionSig* sig, const byte* start,
               const byte* end)
       : Decoder(start, end),
         module_(module),
         sig_(sig),
-        total_locals_(0),
         local_types_(nullptr) {}
-  ModuleEnv* module_;
+  const WasmModule* module_;
   FunctionSig* sig_;
-  size_t total_locals_;
-  ZoneVector<LocalType>* local_types_;
+
+  ZoneVector<ValueType>* local_types_;
+
+  size_t total_locals() const {
+    return local_types_ == nullptr ? 0 : local_types_->size();
+  }
+
+  static bool DecodeLocals(Decoder* decoder, const FunctionSig* sig,
+                           ZoneVector<ValueType>* type_list) {
+    DCHECK_NOT_NULL(type_list);
+    // Initialize from signature.
+    if (sig != nullptr) {
+      type_list->reserve(sig->parameter_count());
+      for (size_t i = 0; i < sig->parameter_count(); ++i) {
+        type_list->push_back(sig->GetParam(i));
+      }
+    }
+    // Decode local declarations, if any.
+    uint32_t entries = decoder->consume_u32v("local decls count");
+    if (decoder->failed()) return false;
+
+    TRACE("local decls count: %u\n", entries);
+    while (entries-- > 0 && decoder->ok() && decoder->more()) {
+      uint32_t count = decoder->consume_u32v("local count");
+      if (decoder->failed()) return false;
+
+      if ((count + type_list->size()) > kMaxNumWasmLocals) {
+        decoder->error(decoder->pc() - 1, "local count too large");
+        return false;
+      }
+      byte code = decoder->consume_u8("local type");
+      if (decoder->failed()) return false;
+
+      ValueType type;
+      switch (code) {
+        case kLocalI32:
+          type = kWasmI32;
+          break;
+        case kLocalI64:
+          type = kWasmI64;
+          break;
+        case kLocalF32:
+          type = kWasmF32;
+          break;
+        case kLocalF64:
+          type = kWasmF64;
+          break;
+        case kLocalS128:
+          type = kWasmS128;
+          break;
+        default:
+          decoder->error(decoder->pc() - 1, "invalid local type");
+          return false;
+      }
+      type_list->insert(type_list->end(), count, type);
+    }
+    DCHECK(decoder->ok());
+    return true;
+  }
+
+  static BitVector* AnalyzeLoopAssignment(Decoder* decoder, const byte* pc,
+                                          int locals_count, Zone* zone) {
+    if (pc >= decoder->end()) return nullptr;
+    if (*pc != kExprLoop) return nullptr;
+
+    BitVector* assigned = new (zone) BitVector(locals_count, zone);
+    int depth = 0;
+    // Iteratively process all AST nodes nested inside the loop.
+    while (pc < decoder->end() && decoder->ok()) {
+      WasmOpcode opcode = static_cast<WasmOpcode>(*pc);
+      unsigned length = 1;
+      switch (opcode) {
+        case kExprLoop:
+        case kExprIf:
+        case kExprBlock:
+        case kExprTry:
+          length = OpcodeLength(decoder, pc);
+          depth++;
+          break;
+        case kExprSetLocal:  // fallthru
+        case kExprTeeLocal: {
+          LocalIndexOperand operand(decoder, pc);
+          if (assigned->length() > 0 &&
+              operand.index < static_cast<uint32_t>(assigned->length())) {
+            // Unverified code might have an out-of-bounds index.
+            assigned->Add(operand.index);
+          }
+          length = 1 + operand.length;
+          break;
+        }
+        case kExprEnd:
+          depth--;
+          break;
+        default:
+          length = OpcodeLength(decoder, pc);
+          break;
+      }
+      if (depth <= 0) break;
+      pc += length;
+    }
+    return decoder->ok() ? assigned : nullptr;
+  }
 
   inline bool Validate(const byte* pc, LocalIndexOperand& operand) {
-    if (operand.index < total_locals_) {
+    if (operand.index < total_locals()) {
       if (local_types_) {
         operand.type = local_types_->at(operand.index);
       } else {
-        operand.type = kAstStmt;
+        operand.type = kWasmStmt;
       }
       return true;
     }
@@ -190,9 +288,8 @@ class WasmDecoder : public Decoder {
   }
 
   inline bool Validate(const byte* pc, GlobalIndexOperand& operand) {
-    ModuleEnv* m = module_;
-    if (m && m->module && operand.index < m->module->globals.size()) {
-      operand.global = &m->module->globals[operand.index];
+    if (module_ != nullptr && operand.index < module_->globals.size()) {
+      operand.global = &module_->globals[operand.index];
       operand.type = operand.global->type;
       return true;
     }
@@ -201,9 +298,8 @@ class WasmDecoder : public Decoder {
   }
 
   inline bool Complete(const byte* pc, CallFunctionOperand& operand) {
-    ModuleEnv* m = module_;
-    if (m && m->module && operand.index < m->module->functions.size()) {
-      operand.sig = m->module->functions[operand.index].sig;
+    if (module_ != nullptr && operand.index < module_->functions.size()) {
+      operand.sig = module_->functions[operand.index].sig;
       return true;
     }
     return false;
@@ -218,17 +314,15 @@ class WasmDecoder : public Decoder {
   }
 
   inline bool Complete(const byte* pc, CallIndirectOperand& operand) {
-    ModuleEnv* m = module_;
-    if (m && m->module && operand.index < m->module->signatures.size()) {
-      operand.sig = m->module->signatures[operand.index];
+    if (module_ != nullptr && operand.index < module_->signatures.size()) {
+      operand.sig = module_->signatures[operand.index];
       return true;
     }
     return false;
   }
 
   inline bool Validate(const byte* pc, CallIndirectOperand& operand) {
-    uint32_t table_index = 0;
-    if (!module_->IsValidTable(table_index)) {
+    if (module_ == nullptr || module_->function_tables.empty()) {
       error("function table has to exist to execute call_indirect");
       return false;
     }
@@ -264,33 +358,33 @@ class WasmDecoder : public Decoder {
     }
   }
 
-  unsigned OpcodeLength(const byte* pc) {
+  static unsigned OpcodeLength(Decoder* decoder, const byte* pc) {
     switch (static_cast<byte>(*pc)) {
 #define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
       FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
       FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
 #undef DECLARE_OPCODE_CASE
       {
-        MemoryAccessOperand operand(this, pc, UINT32_MAX);
+        MemoryAccessOperand operand(decoder, pc, UINT32_MAX);
         return 1 + operand.length;
       }
       case kExprBr:
       case kExprBrIf: {
-        BreakDepthOperand operand(this, pc);
+        BreakDepthOperand operand(decoder, pc);
         return 1 + operand.length;
       }
       case kExprSetGlobal:
       case kExprGetGlobal: {
-        GlobalIndexOperand operand(this, pc);
+        GlobalIndexOperand operand(decoder, pc);
         return 1 + operand.length;
       }
 
       case kExprCallFunction: {
-        CallFunctionOperand operand(this, pc);
+        CallFunctionOperand operand(decoder, pc);
         return 1 + operand.length;
       }
       case kExprCallIndirect: {
-        CallIndirectOperand operand(this, pc);
+        CallIndirectOperand operand(decoder, pc);
         return 1 + operand.length;
       }
 
@@ -298,7 +392,7 @@ class WasmDecoder : public Decoder {
       case kExprIf:  // fall thru
       case kExprLoop:
       case kExprBlock: {
-        BlockTypeOperand operand(this, pc);
+        BlockTypeOperand operand(decoder, pc);
         return 1 + operand.length;
       }
 
@@ -306,35 +400,33 @@ class WasmDecoder : public Decoder {
       case kExprTeeLocal:
       case kExprGetLocal:
       case kExprCatch: {
-        LocalIndexOperand operand(this, pc);
+        LocalIndexOperand operand(decoder, pc);
         return 1 + operand.length;
       }
       case kExprBrTable: {
-        BranchTableOperand operand(this, pc);
-        BranchTableIterator iterator(this, operand);
+        BranchTableOperand operand(decoder, pc);
+        BranchTableIterator iterator(decoder, operand);
         return 1 + iterator.length();
       }
       case kExprI32Const: {
-        ImmI32Operand operand(this, pc);
+        ImmI32Operand operand(decoder, pc);
         return 1 + operand.length;
       }
       case kExprI64Const: {
-        ImmI64Operand operand(this, pc);
+        ImmI64Operand operand(decoder, pc);
         return 1 + operand.length;
       }
       case kExprGrowMemory:
       case kExprMemorySize: {
-        MemoryIndexOperand operand(this, pc);
+        MemoryIndexOperand operand(decoder, pc);
         return 1 + operand.length;
       }
-      case kExprI8Const:
-        return 2;
       case kExprF32Const:
         return 5;
       case kExprF64Const:
         return 9;
       case kSimdPrefix: {
-        byte simd_index = checked_read_u8(pc, 1, "simd_index");
+        byte simd_index = decoder->checked_read_u8(pc, 1, "simd_index");
         WasmOpcode opcode =
             static_cast<WasmOpcode>(kSimdPrefix << 8 | simd_index);
         switch (opcode) {
@@ -351,7 +443,7 @@ class WasmDecoder : public Decoder {
             return 3;
           }
           default:
-            error("invalid SIMD opcode");
+            decoder->error(pc, "invalid SIMD opcode");
             return 2;
         }
       }
@@ -363,24 +455,24 @@ class WasmDecoder : public Decoder {
 
 static const int32_t kNullCatch = -1;
 
-// The full WASM decoder for bytecode. Both verifies bytecode and generates
-// a TurboFan IR graph.
+// The full WASM decoder for bytecode. Verifies bytecode and, optionally,
+// generates a TurboFan IR graph.
 class WasmFullDecoder : public WasmDecoder {
  public:
+  WasmFullDecoder(Zone* zone, const wasm::WasmModule* module,
+                  const FunctionBody& body)
+      : WasmFullDecoder(zone, module, nullptr, body) {}
+
   WasmFullDecoder(Zone* zone, TFBuilder* builder, const FunctionBody& body)
-      : WasmDecoder(body.module, body.sig, body.start, body.end),
-        zone_(zone),
-        builder_(builder),
-        base_(body.base),
-        local_type_vec_(zone),
-        stack_(zone),
-        control_(zone),
-        last_end_found_(false),
-        current_catch_(kNullCatch) {
-    local_types_ = &local_type_vec_;
-  }
+      : WasmFullDecoder(zone, builder->module_env() == nullptr
+                                  ? nullptr
+                                  : builder->module_env()->module,
+                        builder, body) {}
 
   bool Decode() {
+    if (FLAG_wasm_code_fuzzer_gen_test) {
+      PrintRawWasmCode(start_, end_);
+    }
     base::ElapsedTimer decode_timer;
     if (FLAG_trace_wasm_decode_time) {
       decode_timer.Start();
@@ -393,47 +485,21 @@ class WasmFullDecoder : public WasmDecoder {
       return false;
     }
 
-    DecodeLocalDecls();
+    DCHECK_EQ(0, local_types_->size());
+    WasmDecoder::DecodeLocals(this, sig_, local_types_);
     InitSsaEnv();
     DecodeFunctionBody();
 
     if (failed()) return TraceFailed();
 
-#if IMPLICIT_FUNCTION_END
-    // With implicit end support (old style), the function block
-    // remains on the stack. Other control blocks are an error.
-    if (control_.size() > 1) {
-      error(pc_, control_.back().pc, "unterminated control structure");
-      return TraceFailed();
-    }
-
-    // Assume an implicit end to the function body block.
-    if (control_.size() == 1) {
-      Control* c = &control_.back();
-      if (ssa_env_->go()) {
-        FallThruTo(c);
-      }
-
-      if (c->end_env->go()) {
-        // Push the end values onto the stack.
-        stack_.resize(c->stack_depth);
-        if (c->merge.arity == 1) {
-          stack_.push_back(c->merge.vals.first);
-        } else {
-          for (unsigned i = 0; i < c->merge.arity; i++) {
-            stack_.push_back(c->merge.vals.array[i]);
-          }
-        }
-
-        TRACE("  @%-8d #xx:%-20s|", startrel(pc_), "ImplicitReturn");
-        SetEnv("function:end", c->end_env);
-        DoReturn();
-        TRACE("\n");
-      }
-    }
-#else
     if (!control_.empty()) {
-      error(pc_, control_.back().pc, "unterminated control structure");
+      // Generate a better error message whether the unterminated control
+      // structure is the function body block or an innner structure.
+      if (control_.size() > 1) {
+        error(pc_, control_.back().pc, "unterminated control structure");
+      } else {
+        error("function body must end with \"end\" opcode.");
+      }
       return TraceFailed();
     }
 
@@ -441,7 +507,6 @@ class WasmFullDecoder : public WasmDecoder {
       error("function body must end with \"end\" opcode.");
       return false;
     }
-#endif
 
     if (FLAG_trace_wasm_decode_time) {
       double ms = decode_timer.Elapsed().InMillisecondsF();
@@ -459,36 +524,21 @@ class WasmFullDecoder : public WasmDecoder {
     return false;
   }
 
-  bool DecodeLocalDecls(AstLocalDecls& decls) {
-    DecodeLocalDecls();
-    if (failed()) return false;
-    decls.decls_encoded_size = pc_offset();
-    decls.local_types.reserve(local_type_vec_.size());
-    for (size_t pos = 0; pos < local_type_vec_.size();) {
-      uint32_t count = 0;
-      LocalType type = local_type_vec_[pos];
-      while (pos < local_type_vec_.size() && local_type_vec_[pos] == type) {
-        pos++;
-        count++;
-      }
-      decls.local_types.push_back(std::pair<LocalType, uint32_t>(type, count));
-    }
-    decls.total_local_count = static_cast<uint32_t>(local_type_vec_.size());
-    return true;
-  }
-
-  BitVector* AnalyzeLoopAssignmentForTesting(const byte* pc,
-                                             size_t num_locals) {
-    total_locals_ = num_locals;
-    local_type_vec_.reserve(num_locals);
-    if (num_locals > local_type_vec_.size()) {
-      local_type_vec_.insert(local_type_vec_.end(),
-                             num_locals - local_type_vec_.size(), kAstI32);
-    }
-    return AnalyzeLoopAssignment(pc);
+ private:
+  WasmFullDecoder(Zone* zone, const wasm::WasmModule* module,
+                  TFBuilder* builder, const FunctionBody& body)
+      : WasmDecoder(module, body.sig, body.start, body.end),
+        zone_(zone),
+        builder_(builder),
+        base_(body.base),
+        local_type_vec_(zone),
+        stack_(zone),
+        control_(zone),
+        last_end_found_(false),
+        current_catch_(kNullCatch) {
+    local_types_ = &local_type_vec_;
   }
 
- private:
   static const size_t kErrorMsgSize = 128;
 
   Zone* zone_;
@@ -497,7 +547,7 @@ class WasmFullDecoder : public WasmDecoder {
 
   SsaEnv* ssa_env_;
 
-  ZoneVector<LocalType> local_type_vec_;  // types of local variables.
+  ZoneVector<ValueType> local_type_vec_;  // types of local variables.
   ZoneVector<Value> stack_;               // stack of values.
   ZoneVector<Control> control_;           // stack of blocks, loops, and ifs.
   bool last_end_found_;
@@ -521,11 +571,11 @@ class WasmFullDecoder : public WasmDecoder {
       // Initialize local variables.
       uint32_t index = 0;
       while (index < sig_->parameter_count()) {
-        ssa_env->locals[index] = builder_->Param(index, local_type_vec_[index]);
+        ssa_env->locals[index] = builder_->Param(index);
         index++;
       }
       while (index < local_type_vec_.size()) {
-        LocalType type = local_type_vec_[index];
+        ValueType type = local_type_vec_[index];
         TFNode* node = DefaultValue(type);
         while (index < local_type_vec_.size() &&
                local_type_vec_[index] == type) {
@@ -533,27 +583,28 @@ class WasmFullDecoder : public WasmDecoder {
           ssa_env->locals[index++] = node;
         }
       }
-      builder_->set_module(module_);
     }
     ssa_env->control = start;
     ssa_env->effect = start;
     SetEnv("initial", ssa_env);
     if (builder_) {
-      builder_->StackCheck(position());
+      // The function-prologue stack check is associated with position 0, which
+      // is never a position of any instruction in the function.
+      builder_->StackCheck(0);
     }
   }
 
-  TFNode* DefaultValue(LocalType type) {
+  TFNode* DefaultValue(ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         return builder_->Int32Constant(0);
-      case kAstI64:
+      case kWasmI64:
         return builder_->Int64Constant(0);
-      case kAstF32:
+      case kWasmF32:
         return builder_->Float32Constant(0);
-      case kAstF64:
+      case kWasmF64:
         return builder_->Float64Constant(0);
-      case kAstS128:
+      case kWasmS128:
         return builder_->CreateS128Value(0);
       default:
         UNREACHABLE();
@@ -572,58 +623,19 @@ class WasmFullDecoder : public WasmDecoder {
     return bytes;
   }
 
-  // Decodes the locals declarations, if any, populating {local_type_vec_}.
-  void DecodeLocalDecls() {
-    DCHECK_EQ(0u, local_type_vec_.size());
-    // Initialize {local_type_vec} from signature.
-    if (sig_) {
-      local_type_vec_.reserve(sig_->parameter_count());
-      for (size_t i = 0; i < sig_->parameter_count(); ++i) {
-        local_type_vec_.push_back(sig_->GetParam(i));
-      }
-    }
-    // Decode local declarations, if any.
-    uint32_t entries = consume_u32v("local decls count");
-    TRACE("local decls count: %u\n", entries);
-    while (entries-- > 0 && pc_ < limit_) {
-      uint32_t count = consume_u32v("local count");
-      if (count > kMaxNumWasmLocals) {
-        error(pc_ - 1, "local count too large");
-        return;
-      }
-      byte code = consume_u8("local type");
-      LocalType type;
-      switch (code) {
-        case kLocalI32:
-          type = kAstI32;
-          break;
-        case kLocalI64:
-          type = kAstI64;
-          break;
-        case kLocalF32:
-          type = kAstF32;
-          break;
-        case kLocalF64:
-          type = kAstF64;
-          break;
-        case kLocalS128:
-          type = kAstS128;
-          break;
-        default:
-          error(pc_ - 1, "invalid local type");
-          return;
-      }
-      local_type_vec_.insert(local_type_vec_.end(), count, type);
+  bool CheckHasMemory() {
+    if (!module_->has_memory) {
+      error(pc_ - 1, "memory instruction with no memory");
     }
-    total_locals_ = local_type_vec_.size();
+    return module_->has_memory;
   }
 
   // Decodes the body of a function.
   void DecodeFunctionBody() {
     TRACE("wasm-decode %p...%p (module+%d, %d bytes) %s\n",
           reinterpret_cast<const void*>(start_),
-          reinterpret_cast<const void*>(limit_), baserel(pc_),
-          static_cast<int>(limit_ - start_), builder_ ? "graph building" : "");
+          reinterpret_cast<const void*>(end_), baserel(pc_),
+          static_cast<int>(end_ - start_), builder_ ? "graph building" : "");
 
     {
       // Set up initial function block.
@@ -643,9 +655,7 @@ class WasmFullDecoder : public WasmDecoder {
       }
     }
 
-    if (pc_ >= limit_) return;  // Nothing to do.
-
-    while (true) {  // decoding loop.
+    while (pc_ < end_) {  // decoding loop.
       unsigned len = 1;
       WasmOpcode opcode = static_cast<WasmOpcode>(*pc_);
       if (!WasmOpcodes::IsPrefixOpcode(opcode)) {
@@ -673,8 +683,12 @@ class WasmFullDecoder : public WasmDecoder {
           }
           case kExprThrow: {
             CHECK_PROTOTYPE_OPCODE(wasm_eh_prototype);
-            Value value = Pop(0, kAstI32);
+            Value value = Pop(0, kWasmI32);
             BUILD(Throw, value.node);
+            // TODO(titzer): Throw should end control, but currently we build a
+            // (reachable) runtime call instead of connecting it directly to
+            // end.
+            //            EndControl();
             break;
           }
           case kExprTry: {
@@ -710,9 +724,7 @@ class WasmFullDecoder : public WasmDecoder {
               break;
             }
 
-            if (ssa_env_->go()) {
-              MergeValuesInto(c);
-            }
+            FallThruTo(c);
             stack_.resize(c->stack_depth);
 
             DCHECK_NOT_NULL(c->try_info);
@@ -746,7 +758,7 @@ class WasmFullDecoder : public WasmDecoder {
           case kExprIf: {
             // Condition on top of stack. Split environments for branches.
             BlockTypeOperand operand(this, pc_);
-            Value cond = Pop(0, kAstI32);
+            Value cond = Pop(0, kWasmI32);
             TFNode* if_true = nullptr;
             TFNode* if_false = nullptr;
             BUILD(BranchNoHint, cond.node, &if_true, &if_false);
@@ -776,8 +788,8 @@ class WasmFullDecoder : public WasmDecoder {
               break;
             }
             FallThruTo(c);
-            // Switch to environment for false branch.
             stack_.resize(c->stack_depth);
+            // Switch to environment for false branch.
             SetEnv("if_else:false", c->false_env);
             c->false_env = nullptr;  // record that an else is already seen
             break;
@@ -791,7 +803,8 @@ class WasmFullDecoder : public WasmDecoder {
             Control* c = &control_.back();
             if (c->is_loop()) {
               // A loop just leaves the values on the stack.
-              TypeCheckLoopFallThru(c);
+              TypeCheckFallThru(c);
+              if (c->unreachable) PushEndValues(c);
               PopControl();
               SetEnv("loop:end", ssa_env_);
               break;
@@ -800,8 +813,7 @@ class WasmFullDecoder : public WasmDecoder {
               if (c->false_env != nullptr) {
                 // End the true branch of a one-armed if.
                 Goto(c->false_env, c->end_env);
-                if (ssa_env_->go() &&
-                    static_cast<int>(stack_.size()) != c->stack_depth) {
+                if (!c->unreachable && stack_.size() != c->stack_depth) {
                   error("end of if expected empty stack");
                   stack_.resize(c->stack_depth);
                 }
@@ -824,23 +836,13 @@ class WasmFullDecoder : public WasmDecoder {
             }
             FallThruTo(c);
             SetEnv(name, c->end_env);
+            PushEndValues(c);
 
-            // Push the end values onto the stack.
-            stack_.resize(c->stack_depth);
-            if (c->merge.arity == 1) {
-              stack_.push_back(c->merge.vals.first);
-            } else {
-              for (unsigned i = 0; i < c->merge.arity; i++) {
-                stack_.push_back(c->merge.vals.array[i]);
-              }
-            }
-
-            PopControl();
-
-            if (control_.empty()) {
-              // If the last (implicit) control was popped, check we are at end.
+            if (control_.size() == 1) {
+              // If at the last (implicit) control, check we are at end.
               if (pc_ + 1 != end_) {
                 error(pc_, pc_ + 1, "trailing code after function end");
+                break;
               }
               last_end_found_ = true;
               if (ssa_env_->go()) {
@@ -848,25 +850,18 @@ class WasmFullDecoder : public WasmDecoder {
                 TRACE("  @%-8d #xx:%-20s|", startrel(pc_), "ImplicitReturn");
                 DoReturn();
                 TRACE("\n");
+              } else {
+                TypeCheckFallThru(c);
               }
-              return;
             }
+            PopControl();
             break;
           }
           case kExprSelect: {
-            Value cond = Pop(2, kAstI32);
+            Value cond = Pop(2, kWasmI32);
             Value fval = Pop();
-            Value tval = Pop();
-            if (tval.type == kAstStmt || tval.type != fval.type) {
-              if (tval.type != kAstEnd && fval.type != kAstEnd) {
-                error("type mismatch in select");
-                break;
-              }
-            }
+            Value tval = Pop(0, fval.type);
             if (build()) {
-              DCHECK(tval.type != kAstEnd);
-              DCHECK(fval.type != kAstEnd);
-              DCHECK(cond.type != kAstEnd);
               TFNode* controls[2];
               builder_->BranchNoHint(cond.node, &controls[0], &controls[1]);
               TFNode* merge = builder_->Merge(2, controls);
@@ -875,7 +870,7 @@ class WasmFullDecoder : public WasmDecoder {
               Push(tval.type, phi);
               ssa_env_->control = merge;
             } else {
-              Push(tval.type, nullptr);
+              Push(tval.type == kWasmVar ? fval.type : tval.type, nullptr);
             }
             break;
           }
@@ -890,7 +885,7 @@ class WasmFullDecoder : public WasmDecoder {
           }
           case kExprBrIf: {
             BreakDepthOperand operand(this, pc_);
-            Value cond = Pop(0, kAstI32);
+            Value cond = Pop(0, kWasmI32);
             if (ok() && Validate(pc_, operand, control_)) {
               SsaEnv* fenv = ssa_env_;
               SsaEnv* tenv = Split(fenv);
@@ -907,7 +902,7 @@ class WasmFullDecoder : public WasmDecoder {
             BranchTableOperand operand(this, pc_);
             BranchTableIterator iterator(this, operand);
             if (Validate(pc_, operand, control_.size())) {
-              Value key = Pop(0, kAstI32);
+              Value key = Pop(0, kWasmI32);
               if (failed()) break;
 
               SsaEnv* break_env = ssa_env_;
@@ -917,6 +912,7 @@ class WasmFullDecoder : public WasmDecoder {
 
                 SsaEnv* copy = Steal(break_env);
                 ssa_env_ = copy;
+                MergeValues* merge = nullptr;
                 while (ok() && iterator.has_next()) {
                   uint32_t i = iterator.cur_index();
                   const byte* pos = iterator.pc();
@@ -930,6 +926,27 @@ class WasmFullDecoder : public WasmDecoder {
                                           ? BUILD(IfDefault, sw)
                                           : BUILD(IfValue, i, sw);
                   BreakTo(target);
+
+                  // Check that label types match up.
+                  Control* c = &control_[control_.size() - target - 1];
+                  if (i == 0) {
+                    merge = &c->merge;
+                  } else if (merge->arity != c->merge.arity) {
+                    error(pos, pos,
+                          "inconsistent arity in br_table target %d"
+                          " (previous was %u, this one %u)",
+                          i, merge->arity, c->merge.arity);
+                  } else if (control_.back().unreachable) {
+                    for (uint32_t j = 0; ok() && j < merge->arity; ++j) {
+                      if ((*merge)[j].type != c->merge[j].type) {
+                        error(pos, pos,
+                              "type error in br_table target %d operand %d"
+                              " (previous expected %s, this one %s)",
+                              i, j, WasmOpcodes::TypeName((*merge)[j].type),
+                              WasmOpcodes::TypeName(c->merge[j].type));
+                      }
+                    }
+                  }
                 }
                 if (failed()) break;
               } else {
@@ -946,6 +963,7 @@ class WasmFullDecoder : public WasmDecoder {
               ssa_env_ = break_env;
             }
             len = 1 + iterator.length();
+            EndControl();
             break;
           }
           case kExprReturn: {
@@ -957,33 +975,27 @@ class WasmFullDecoder : public WasmDecoder {
             EndControl();
             break;
           }
-          case kExprI8Const: {
-            ImmI8Operand operand(this, pc_);
-            Push(kAstI32, BUILD(Int32Constant, operand.value));
-            len = 1 + operand.length;
-            break;
-          }
           case kExprI32Const: {
             ImmI32Operand operand(this, pc_);
-            Push(kAstI32, BUILD(Int32Constant, operand.value));
+            Push(kWasmI32, BUILD(Int32Constant, operand.value));
             len = 1 + operand.length;
             break;
           }
           case kExprI64Const: {
             ImmI64Operand operand(this, pc_);
-            Push(kAstI64, BUILD(Int64Constant, operand.value));
+            Push(kWasmI64, BUILD(Int64Constant, operand.value));
             len = 1 + operand.length;
             break;
           }
           case kExprF32Const: {
             ImmF32Operand operand(this, pc_);
-            Push(kAstF32, BUILD(Float32Constant, operand.value));
+            Push(kWasmF32, BUILD(Float32Constant, operand.value));
             len = 1 + operand.length;
             break;
           }
           case kExprF64Const: {
             ImmF64Operand operand(this, pc_);
-            Push(kAstF64, BUILD(Float64Constant, operand.value));
+            Push(kWasmF64, BUILD(Float64Constant, operand.value));
             len = 1 + operand.length;
             break;
           }
@@ -1045,79 +1057,81 @@ class WasmFullDecoder : public WasmDecoder {
             break;
           }
           case kExprI32LoadMem8S:
-            len = DecodeLoadMem(kAstI32, MachineType::Int8());
+            len = DecodeLoadMem(kWasmI32, MachineType::Int8());
             break;
           case kExprI32LoadMem8U:
-            len = DecodeLoadMem(kAstI32, MachineType::Uint8());
+            len = DecodeLoadMem(kWasmI32, MachineType::Uint8());
             break;
           case kExprI32LoadMem16S:
-            len = DecodeLoadMem(kAstI32, MachineType::Int16());
+            len = DecodeLoadMem(kWasmI32, MachineType::Int16());
             break;
           case kExprI32LoadMem16U:
-            len = DecodeLoadMem(kAstI32, MachineType::Uint16());
+            len = DecodeLoadMem(kWasmI32, MachineType::Uint16());
             break;
           case kExprI32LoadMem:
-            len = DecodeLoadMem(kAstI32, MachineType::Int32());
+            len = DecodeLoadMem(kWasmI32, MachineType::Int32());
             break;
           case kExprI64LoadMem8S:
-            len = DecodeLoadMem(kAstI64, MachineType::Int8());
+            len = DecodeLoadMem(kWasmI64, MachineType::Int8());
             break;
           case kExprI64LoadMem8U:
-            len = DecodeLoadMem(kAstI64, MachineType::Uint8());
+            len = DecodeLoadMem(kWasmI64, MachineType::Uint8());
             break;
           case kExprI64LoadMem16S:
-            len = DecodeLoadMem(kAstI64, MachineType::Int16());
+            len = DecodeLoadMem(kWasmI64, MachineType::Int16());
             break;
           case kExprI64LoadMem16U:
-            len = DecodeLoadMem(kAstI64, MachineType::Uint16());
+            len = DecodeLoadMem(kWasmI64, MachineType::Uint16());
             break;
           case kExprI64LoadMem32S:
-            len = DecodeLoadMem(kAstI64, MachineType::Int32());
+            len = DecodeLoadMem(kWasmI64, MachineType::Int32());
             break;
           case kExprI64LoadMem32U:
-            len = DecodeLoadMem(kAstI64, MachineType::Uint32());
+            len = DecodeLoadMem(kWasmI64, MachineType::Uint32());
             break;
           case kExprI64LoadMem:
-            len = DecodeLoadMem(kAstI64, MachineType::Int64());
+            len = DecodeLoadMem(kWasmI64, MachineType::Int64());
             break;
           case kExprF32LoadMem:
-            len = DecodeLoadMem(kAstF32, MachineType::Float32());
+            len = DecodeLoadMem(kWasmF32, MachineType::Float32());
             break;
           case kExprF64LoadMem:
-            len = DecodeLoadMem(kAstF64, MachineType::Float64());
+            len = DecodeLoadMem(kWasmF64, MachineType::Float64());
             break;
           case kExprI32StoreMem8:
-            len = DecodeStoreMem(kAstI32, MachineType::Int8());
+            len = DecodeStoreMem(kWasmI32, MachineType::Int8());
             break;
           case kExprI32StoreMem16:
-            len = DecodeStoreMem(kAstI32, MachineType::Int16());
+            len = DecodeStoreMem(kWasmI32, MachineType::Int16());
             break;
           case kExprI32StoreMem:
-            len = DecodeStoreMem(kAstI32, MachineType::Int32());
+            len = DecodeStoreMem(kWasmI32, MachineType::Int32());
             break;
           case kExprI64StoreMem8:
-            len = DecodeStoreMem(kAstI64, MachineType::Int8());
+            len = DecodeStoreMem(kWasmI64, MachineType::Int8());
             break;
           case kExprI64StoreMem16:
-            len = DecodeStoreMem(kAstI64, MachineType::Int16());
+            len = DecodeStoreMem(kWasmI64, MachineType::Int16());
             break;
           case kExprI64StoreMem32:
-            len = DecodeStoreMem(kAstI64, MachineType::Int32());
+            len = DecodeStoreMem(kWasmI64, MachineType::Int32());
             break;
           case kExprI64StoreMem:
-            len = DecodeStoreMem(kAstI64, MachineType::Int64());
+            len = DecodeStoreMem(kWasmI64, MachineType::Int64());
             break;
           case kExprF32StoreMem:
-            len = DecodeStoreMem(kAstF32, MachineType::Float32());
+            len = DecodeStoreMem(kWasmF32, MachineType::Float32());
             break;
           case kExprF64StoreMem:
-            len = DecodeStoreMem(kAstF64, MachineType::Float64());
+            len = DecodeStoreMem(kWasmF64, MachineType::Float64());
             break;
           case kExprGrowMemory: {
+            if (!CheckHasMemory()) break;
             MemoryIndexOperand operand(this, pc_);
+            DCHECK_NOT_NULL(module_);
             if (module_->origin != kAsmJsOrigin) {
-              Value val = Pop(0, kAstI32);
-              Push(kAstI32, BUILD(GrowMemory, val.node));
+              Value val = Pop(0, kWasmI32);
+              Push(kWasmI32, BUILD(GrowMemory, val.node));
             } else {
               error("grow_memory is not supported for asmjs modules");
             }
@@ -1125,8 +1139,9 @@ class WasmFullDecoder : public WasmDecoder {
             break;
           }
           case kExprMemorySize: {
+            if (!CheckHasMemory()) break;
             MemoryIndexOperand operand(this, pc_);
-            Push(kAstI32, BUILD(CurrentMemoryPages));
+            Push(kWasmI32, BUILD(CurrentMemoryPages));
             len = 1 + operand.length;
             break;
           }
@@ -1144,7 +1159,7 @@ class WasmFullDecoder : public WasmDecoder {
           case kExprCallIndirect: {
             CallIndirectOperand operand(this, pc_);
             if (Validate(pc_, operand)) {
-              Value index = Pop(0, kAstI32);
+              Value index = Pop(0, kWasmI32);
               TFNode** buffer = PopArgs(operand.sig);
               if (buffer) buffer[0] = index.node;
               TFNode** rets = nullptr;
@@ -1165,7 +1180,7 @@ class WasmFullDecoder : public WasmDecoder {
             break;
           }
           case kAtomicPrefix: {
-            if (!module_ || module_->origin != kAsmJsOrigin) {
+            if (module_ == nullptr || module_->origin != kAsmJsOrigin) {
               error("Atomics are allowed only in AsmJs modules");
               break;
             }
@@ -1184,7 +1199,7 @@ class WasmFullDecoder : public WasmDecoder {
           }
           default: {
             // Deal with special asmjs opcodes.
-            if (module_ && module_->origin == kAsmJsOrigin) {
+            if (module_ != nullptr && module_->origin == kAsmJsOrigin) {
               sig = WasmOpcodes::AsmjsSignature(opcode);
               if (sig) {
                 BuildSimpleOperator(opcode, sig);
@@ -1199,6 +1214,35 @@ class WasmFullDecoder : public WasmDecoder {
 
 #if DEBUG
       if (FLAG_trace_wasm_decoder) {
+        PrintF(" ");
+        for (size_t i = 0; i < control_.size(); ++i) {
+          Control* c = &control_[i];
+          enum ControlKind {
+            kControlIf,
+            kControlBlock,
+            kControlLoop,
+            kControlTry
+          };
+          switch (c->kind) {
+            case kControlIf:
+              PrintF("I");
+              break;
+            case kControlBlock:
+              PrintF("B");
+              break;
+            case kControlLoop:
+              PrintF("L");
+              break;
+            case kControlTry:
+              PrintF("T");
+              break;
+            default:
+              break;
+          }
+          PrintF("%u", c->merge.arity);
+          if (c->unreachable) PrintF("*");
+        }
+        PrintF(" | ");
         for (size_t i = 0; i < stack_.size(); ++i) {
           Value& val = stack_[i];
           WasmOpcode opcode = static_cast<WasmOpcode>(*val.pc);
@@ -1228,20 +1272,23 @@ class WasmFullDecoder : public WasmDecoder {
             default:
               break;
           }
+          if (val.node == nullptr) PrintF("?");
         }
         PrintF("\n");
       }
 #endif
       pc_ += len;
-      if (pc_ >= limit_) {
-        // End of code reached or exceeded.
-        if (pc_ > limit_ && ok()) error("Beyond end of code");
-        return;
-      }
     }  // end decode loop
+    if (pc_ > end_ && ok()) error("Beyond end of code");
   }
 
-  void EndControl() { ssa_env_->Kill(SsaEnv::kControlEnd); }
+  void EndControl() {
+    ssa_env_->Kill(SsaEnv::kControlEnd);
+    if (!control_.empty()) {
+      stack_.resize(control_.back().stack_depth);
+      control_.back().unreachable = true;
+    }
+  }
 
   void SetBlockType(Control* c, BlockTypeOperand& operand) {
     c->merge.arity = operand.arity;
@@ -1273,77 +1320,96 @@ class WasmFullDecoder : public WasmDecoder {
     }
   }
 
-  LocalType GetReturnType(FunctionSig* sig) {
-    return sig->return_count() == 0 ? kAstStmt : sig->GetReturn();
+  ValueType GetReturnType(FunctionSig* sig) {
+    return sig->return_count() == 0 ? kWasmStmt : sig->GetReturn();
   }
 
   void PushBlock(SsaEnv* end_env) {
-    const int stack_depth = static_cast<int>(stack_.size());
     control_.emplace_back(
-        Control::Block(pc_, stack_depth, end_env, current_catch_));
+        Control::Block(pc_, stack_.size(), end_env, current_catch_));
   }
 
   void PushLoop(SsaEnv* end_env) {
-    const int stack_depth = static_cast<int>(stack_.size());
     control_.emplace_back(
-        Control::Loop(pc_, stack_depth, end_env, current_catch_));
+        Control::Loop(pc_, stack_.size(), end_env, current_catch_));
   }
 
   void PushIf(SsaEnv* end_env, SsaEnv* false_env) {
-    const int stack_depth = static_cast<int>(stack_.size());
     control_.emplace_back(
-        Control::If(pc_, stack_depth, end_env, false_env, current_catch_));
+        Control::If(pc_, stack_.size(), end_env, false_env, current_catch_));
   }
 
   void PushTry(SsaEnv* end_env, SsaEnv* catch_env) {
-    const int stack_depth = static_cast<int>(stack_.size());
-    control_.emplace_back(Control::Try(pc_, stack_depth, end_env, zone_,
+    control_.emplace_back(Control::Try(pc_, stack_.size(), end_env, zone_,
                                        catch_env, current_catch_));
     current_catch_ = static_cast<int32_t>(control_.size() - 1);
   }
 
   void PopControl() { control_.pop_back(); }
 
-  int DecodeLoadMem(LocalType type, MachineType mem_type) {
+  int DecodeLoadMem(ValueType type, MachineType mem_type) {
+    if (!CheckHasMemory()) return 0;
     MemoryAccessOperand operand(this, pc_,
                                 ElementSizeLog2Of(mem_type.representation()));
 
-    Value index = Pop(0, kAstI32);
+    Value index = Pop(0, kWasmI32);
     TFNode* node = BUILD(LoadMem, type, mem_type, index.node, operand.offset,
                          operand.alignment, position());
     Push(type, node);
     return 1 + operand.length;
   }
 
-  int DecodeStoreMem(LocalType type, MachineType mem_type) {
+  int DecodeStoreMem(ValueType type, MachineType mem_type) {
+    if (!CheckHasMemory()) return 0;
     MemoryAccessOperand operand(this, pc_,
                                 ElementSizeLog2Of(mem_type.representation()));
     Value val = Pop(1, type);
-    Value index = Pop(0, kAstI32);
+    Value index = Pop(0, kWasmI32);
     BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment,
           val.node, position());
     return 1 + operand.length;
   }
 
-  unsigned ExtractLane(WasmOpcode opcode, LocalType type) {
+  unsigned ExtractLane(WasmOpcode opcode, ValueType type) {
     LaneOperand operand(this, pc_);
     if (Validate(pc_, operand)) {
-      TFNode* input = Pop(0, LocalType::kSimd128).node;
-      TFNode* node = BUILD(SimdExtractLane, opcode, operand.lane, input);
+      compiler::NodeVector inputs(1, zone_);
+      inputs[0] = Pop(0, ValueType::kSimd128).node;
+      TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
       Push(type, node);
     }
     return operand.length;
   }
 
+  unsigned ReplaceLane(WasmOpcode opcode, ValueType type) {
+    LaneOperand operand(this, pc_);
+    if (Validate(pc_, operand)) {
+      compiler::NodeVector inputs(2, zone_);
+      inputs[1] = Pop(1, type).node;
+      inputs[0] = Pop(0, ValueType::kSimd128).node;
+      TFNode* node = BUILD(SimdLaneOp, opcode, operand.lane, inputs);
+      Push(ValueType::kSimd128, node);
+    }
+    return operand.length;
+  }
+
   unsigned DecodeSimdOpcode(WasmOpcode opcode) {
     unsigned len = 0;
     switch (opcode) {
       case kExprI32x4ExtractLane: {
-        len = ExtractLane(opcode, LocalType::kWord32);
+        len = ExtractLane(opcode, ValueType::kWord32);
         break;
       }
       case kExprF32x4ExtractLane: {
-        len = ExtractLane(opcode, LocalType::kFloat32);
+        len = ExtractLane(opcode, ValueType::kFloat32);
+        break;
+      }
+      case kExprI32x4ReplaceLane: {
+        len = ReplaceLane(opcode, ValueType::kWord32);
+        break;
+      }
+      case kExprF32x4ReplaceLane: {
+        len = ReplaceLane(opcode, ValueType::kFloat32);
         break;
       }
       default: {
@@ -1381,12 +1447,25 @@ class WasmFullDecoder : public WasmDecoder {
     EndControl();
   }
 
-  void Push(LocalType type, TFNode* node) {
-    if (type != kAstStmt && type != kAstEnd) {
+  void Push(ValueType type, TFNode* node) {
+    if (type != kWasmStmt) {
       stack_.push_back({pc_, node, type});
     }
   }
 
+  void PushEndValues(Control* c) {
+    DCHECK_EQ(c, &control_.back());
+    stack_.resize(c->stack_depth);
+    if (c->merge.arity == 1) {
+      stack_.push_back(c->merge.vals.first);
+    } else {
+      for (unsigned i = 0; i < c->merge.arity; i++) {
+        stack_.push_back(c->merge.vals.array[i]);
+      }
+    }
+    DCHECK_EQ(c->stack_depth + c->merge.arity, stack_.size());
+  }
+
   void PushReturns(FunctionSig* sig, TFNode** rets) {
     for (size_t i = 0; i < sig->return_count(); i++) {
       // When verifying only, then {rets} will be null, so push null.
@@ -1399,31 +1478,24 @@ class WasmFullDecoder : public WasmDecoder {
     return WasmOpcodes::ShortOpcodeName(static_cast<WasmOpcode>(*pc));
   }
 
-  Value Pop(int index, LocalType expected) {
-    if (!ssa_env_->go()) {
-      // Unreachable code is essentially not typechecked.
-      return {pc_, nullptr, expected};
-    }
+  Value Pop(int index, ValueType expected) {
     Value val = Pop();
-    if (val.type != expected) {
-      if (val.type != kAstEnd) {
-        error(pc_, val.pc, "%s[%d] expected type %s, found %s of type %s",
-              SafeOpcodeNameAt(pc_), index, WasmOpcodes::TypeName(expected),
-              SafeOpcodeNameAt(val.pc), WasmOpcodes::TypeName(val.type));
-      }
+    if (val.type != expected && val.type != kWasmVar && expected != kWasmVar) {
+      error(pc_, val.pc, "%s[%d] expected type %s, found %s of type %s",
+            SafeOpcodeNameAt(pc_), index, WasmOpcodes::TypeName(expected),
+            SafeOpcodeNameAt(val.pc), WasmOpcodes::TypeName(val.type));
     }
     return val;
   }
 
   Value Pop() {
-    if (!ssa_env_->go()) {
-      // Unreachable code is essentially not typechecked.
-      return {pc_, nullptr, kAstEnd};
-    }
     size_t limit = control_.empty() ? 0 : control_.back().stack_depth;
     if (stack_.size() <= limit) {
-      Value val = {pc_, nullptr, kAstStmt};
-      error(pc_, pc_, "%s found empty stack", SafeOpcodeNameAt(pc_));
+      // Popping past the current control start in reachable code.
+      Value val = {pc_, nullptr, kWasmVar};
+      if (!control_.back().unreachable) {
+        error(pc_, pc_, "%s found empty stack", SafeOpcodeNameAt(pc_));
+      }
       return val;
     }
     Value val = stack_.back();
@@ -1431,22 +1503,6 @@ class WasmFullDecoder : public WasmDecoder {
     return val;
   }
 
-  Value PopUpTo(int stack_depth) {
-    if (!ssa_env_->go()) {
-      // Unreachable code is essentially not typechecked.
-      return {pc_, nullptr, kAstEnd};
-    }
-    if (stack_depth == static_cast<int>(stack_.size())) {
-      Value val = {pc_, nullptr, kAstStmt};
-      return val;
-    } else {
-      DCHECK_LE(stack_depth, static_cast<int>(stack_.size()));
-      Value val = Pop();
-      stack_.resize(stack_depth);
-      return val;
-    }
-  }
-
   int baserel(const byte* ptr) {
     return base_ ? static_cast<int>(ptr - base_) : 0;
   }
@@ -1454,17 +1510,17 @@ class WasmFullDecoder : public WasmDecoder {
   int startrel(const byte* ptr) { return static_cast<int>(ptr - start_); }
 
   void BreakTo(unsigned depth) {
-    if (!ssa_env_->go()) return;
     Control* c = &control_[control_.size() - depth - 1];
     if (c->is_loop()) {
       // This is the inner loop block, which does not have a value.
       Goto(ssa_env_, c->end_env);
     } else {
       // Merge the value(s) into the end of the block.
-      if (c->stack_depth + c->merge.arity > stack_.size()) {
+      size_t expected = control_.back().stack_depth + c->merge.arity;
+      if (stack_.size() < expected && !control_.back().unreachable) {
         error(
             pc_, pc_,
-            "expected at least %d values on the stack for br to @%d, found %d",
+            "expected at least %u values on the stack for br to @%d, found %d",
             c->merge.arity, startrel(c->pc),
             static_cast<int>(stack_.size() - c->stack_depth));
         return;
@@ -1474,37 +1530,41 @@ class WasmFullDecoder : public WasmDecoder {
   }
 
   void FallThruTo(Control* c) {
-    if (!ssa_env_->go()) return;
+    DCHECK_EQ(c, &control_.back());
     // Merge the value(s) into the end of the block.
-    int arity = static_cast<int>(c->merge.arity);
-    if (c->stack_depth + arity != static_cast<int>(stack_.size())) {
-      error(pc_, pc_, "expected %d elements on the stack for fallthru to @%d",
-            arity, startrel(c->pc));
+    size_t expected = c->stack_depth + c->merge.arity;
+    if (stack_.size() == expected ||
+        (stack_.size() < expected && c->unreachable)) {
+      MergeValuesInto(c);
+      c->unreachable = false;
       return;
     }
-    MergeValuesInto(c);
+    error(pc_, pc_, "expected %u elements on the stack for fallthru to @%d",
+          c->merge.arity, startrel(c->pc));
   }
 
-  inline Value& GetMergeValueFromStack(Control* c, int i) {
+  inline Value& GetMergeValueFromStack(Control* c, size_t i) {
     return stack_[stack_.size() - c->merge.arity + i];
   }
 
-  void TypeCheckLoopFallThru(Control* c) {
-    if (!ssa_env_->go()) return;
+  void TypeCheckFallThru(Control* c) {
+    DCHECK_EQ(c, &control_.back());
     // Fallthru must match arity exactly.
     int arity = static_cast<int>(c->merge.arity);
-    if (c->stack_depth + arity != static_cast<int>(stack_.size())) {
+    if (c->stack_depth + arity < stack_.size() ||
+        (c->stack_depth + arity != stack_.size() && !c->unreachable)) {
       error(pc_, pc_, "expected %d elements on the stack for fallthru to @%d",
             arity, startrel(c->pc));
       return;
     }
     // Typecheck the values left on the stack.
-    for (unsigned i = 0; i < c->merge.arity; i++) {
+    size_t avail = stack_.size() - c->stack_depth;
+    for (size_t i = avail >= c->merge.arity ? 0 : c->merge.arity - avail;
+         i < c->merge.arity; i++) {
       Value& val = GetMergeValueFromStack(c, i);
-      Value& old =
-          c->merge.arity == 1 ? c->merge.vals.first : c->merge.vals.array[i];
+      Value& old = c->merge[i];
       if (val.type != old.type) {
-        error(pc_, pc_, "type error in merge[%d] (expected %s, got %s)", i,
+        error(pc_, pc_, "type error in merge[%zu] (expected %s, got %s)", i,
               WasmOpcodes::TypeName(old.type), WasmOpcodes::TypeName(val.type));
         return;
       }
@@ -1514,23 +1574,24 @@ class WasmFullDecoder : public WasmDecoder {
   void MergeValuesInto(Control* c) {
     SsaEnv* target = c->end_env;
     bool first = target->state == SsaEnv::kUnreachable;
+    bool reachable = ssa_env_->go();
     Goto(ssa_env_, target);
 
-    for (unsigned i = 0; i < c->merge.arity; i++) {
+    size_t avail = stack_.size() - control_.back().stack_depth;
+    for (size_t i = avail >= c->merge.arity ? 0 : c->merge.arity - avail;
+         i < c->merge.arity; i++) {
       Value& val = GetMergeValueFromStack(c, i);
-      Value& old =
-          c->merge.arity == 1 ? c->merge.vals.first : c->merge.vals.array[i];
-      if (val.type != old.type) {
-        error(pc_, pc_, "type error in merge[%d] (expected %s, got %s)", i,
+      Value& old = c->merge[i];
+      if (val.type != old.type && val.type != kWasmVar) {
+        error(pc_, pc_, "type error in merge[%zu] (expected %s, got %s)", i,
               WasmOpcodes::TypeName(old.type), WasmOpcodes::TypeName(val.type));
         return;
       }
-      if (builder_) {
+      if (builder_ && reachable) {
+        DCHECK_NOT_NULL(val.node);
         old.node =
             first ? val.node : CreateOrMergeIntoPhi(old.type, target->control,
                                                     old.node, val.node);
-      } else {
-        old.node = nullptr;
       }
     }
   }
@@ -1555,13 +1616,13 @@ class WasmFullDecoder : public WasmDecoder {
             break;
         }
       }
-      PrintF("  env = %p, state = %c, reason = %s", static_cast<void*>(env),
+      PrintF("{set_env = %p, state = %c, reason = %s", static_cast<void*>(env),
              state, reason);
       if (env && env->control) {
         PrintF(", control = ");
         compiler::WasmGraphBuilder::PrintDebugName(env->control);
       }
-      PrintF("\n");
+      PrintF("}");
     }
 #endif
     ssa_env_ = env;
@@ -1602,7 +1663,7 @@ class WasmFullDecoder : public WasmDecoder {
     } else {
       DCHECK_EQ(SsaEnv::kMerged, try_info->catch_env->state);
       try_info->exception =
-          CreateOrMergeIntoPhi(kAstI32, try_info->catch_env->control,
+          CreateOrMergeIntoPhi(kWasmI32, try_info->catch_env->control,
                                try_info->exception, if_exception);
     }
 
@@ -1686,7 +1747,7 @@ class WasmFullDecoder : public WasmDecoder {
     return from->Kill();
   }
 
-  TFNode* CreateOrMergeIntoPhi(LocalType type, TFNode* merge, TFNode* tnode,
+  TFNode* CreateOrMergeIntoPhi(ValueType type, TFNode* merge, TFNode* tnode,
                                TFNode* fnode) {
     DCHECK_NOT_NULL(builder_);
     if (builder_->IsPhiWithMerge(tnode, merge)) {
@@ -1710,7 +1771,8 @@ class WasmFullDecoder : public WasmDecoder {
     env->effect = builder_->EffectPhi(1, &env->effect, env->control);
     builder_->Terminate(env->effect, env->control);
     if (FLAG_wasm_loop_assignment_analysis) {
-      BitVector* assigned = AnalyzeLoopAssignment(pc);
+      BitVector* assigned = AnalyzeLoopAssignment(
+          this, pc, static_cast<int>(total_locals()), zone_);
       if (failed()) return env;
       if (assigned != nullptr) {
         // Only introduce phis for variables assigned in this loop.
@@ -1789,52 +1851,10 @@ class WasmFullDecoder : public WasmDecoder {
   }
 
   virtual void onFirstError() {
-    limit_ = start_;     // Terminate decoding loop.
+    end_ = start_;       // Terminate decoding loop.
     builder_ = nullptr;  // Don't build any more nodes.
     TRACE(" !%s\n", error_msg_.get());
   }
-  BitVector* AnalyzeLoopAssignment(const byte* pc) {
-    if (pc >= limit_) return nullptr;
-    if (*pc != kExprLoop) return nullptr;
-
-    BitVector* assigned =
-        new (zone_) BitVector(static_cast<int>(local_type_vec_.size()), zone_);
-    int depth = 0;
-    // Iteratively process all AST nodes nested inside the loop.
-    while (pc < limit_ && ok()) {
-      WasmOpcode opcode = static_cast<WasmOpcode>(*pc);
-      unsigned length = 1;
-      switch (opcode) {
-        case kExprLoop:
-        case kExprIf:
-        case kExprBlock:
-        case kExprTry:
-          length = OpcodeLength(pc);
-          depth++;
-          break;
-        case kExprSetLocal:  // fallthru
-        case kExprTeeLocal: {
-          LocalIndexOperand operand(this, pc);
-          if (assigned->length() > 0 &&
-              operand.index < static_cast<uint32_t>(assigned->length())) {
-            // Unverified code might have an out-of-bounds index.
-            assigned->Add(operand.index);
-          }
-          length = 1 + operand.length;
-          break;
-        }
-        case kExprEnd:
-          depth--;
-          break;
-        default:
-          length = OpcodeLength(pc);
-          break;
-      }
-      if (depth <= 0) break;
-      pc += length;
-    }
-    return ok() ? assigned : nullptr;
-  }
 
   inline wasm::WasmCodePosition position() {
     int offset = static_cast<int>(pc_ - start_);
@@ -1865,30 +1885,33 @@ class WasmFullDecoder : public WasmDecoder {
   }
 };
 
-bool DecodeLocalDecls(AstLocalDecls& decls, const byte* start,
+bool DecodeLocalDecls(BodyLocalDecls* decls, const byte* start,
                       const byte* end) {
-  AccountingAllocator allocator;
-  Zone tmp(&allocator, ZONE_NAME);
-  FunctionBody body = {nullptr, nullptr, nullptr, start, end};
-  WasmFullDecoder decoder(&tmp, nullptr, body);
-  return decoder.DecodeLocalDecls(decls);
+  Decoder decoder(start, end);
+  if (WasmDecoder::DecodeLocals(&decoder, nullptr, &decls->type_list)) {
+    DCHECK(decoder.ok());
+    decls->encoded_size = decoder.pc_offset();
+    return true;
+  }
+  return false;
 }
 
 BytecodeIterator::BytecodeIterator(const byte* start, const byte* end,
-                                   AstLocalDecls* decls)
+                                   BodyLocalDecls* decls)
     : Decoder(start, end) {
   if (decls != nullptr) {
-    if (DecodeLocalDecls(*decls, start, end)) {
-      pc_ += decls->decls_encoded_size;
+    if (DecodeLocalDecls(decls, start, end)) {
+      pc_ += decls->encoded_size;
       if (pc_ > end_) pc_ = end_;
     }
   }
 }
 
 DecodeResult VerifyWasmCode(AccountingAllocator* allocator,
+                            const wasm::WasmModule* module,
                             FunctionBody& body) {
   Zone zone(allocator, ZONE_NAME);
-  WasmFullDecoder decoder(&zone, nullptr, body);
+  WasmFullDecoder decoder(&zone, module, body);
   decoder.Decode();
   return decoder.toResult<DecodeStruct*>(nullptr);
 }
@@ -1902,21 +1925,35 @@ DecodeResult BuildTFGraph(AccountingAllocator* allocator, TFBuilder* builder,
 }
 
 unsigned OpcodeLength(const byte* pc, const byte* end) {
-  WasmDecoder decoder(nullptr, nullptr, pc, end);
-  return decoder.OpcodeLength(pc);
+  Decoder decoder(pc, end);
+  return WasmDecoder::OpcodeLength(&decoder, pc);
 }
 
-void PrintAstForDebugging(const byte* start, const byte* end) {
+void PrintRawWasmCode(const byte* start, const byte* end) {
   AccountingAllocator allocator;
-  OFStream os(stdout);
-  PrintAst(&allocator, FunctionBodyForTesting(start, end), os, nullptr);
+  PrintRawWasmCode(&allocator, FunctionBodyForTesting(start, end), nullptr);
 }
 
-bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
-              std::ostream& os,
-              std::vector<std::tuple<uint32_t, int, int>>* offset_table) {
+namespace {
+const char* RawOpcodeName(WasmOpcode opcode) {
+  switch (opcode) {
+#define DECLARE_NAME_CASE(name, opcode, sig) \
+  case kExpr##name:                          \
+    return "kExpr" #name;
+    FOREACH_OPCODE(DECLARE_NAME_CASE)
+#undef DECLARE_NAME_CASE
+    default:
+      break;
+  }
+  return "Unknown";
+}
+}  // namespace
+
+bool PrintRawWasmCode(AccountingAllocator* allocator, const FunctionBody& body,
+                      const wasm::WasmModule* module) {
+  OFStream os(stdout);
   Zone zone(allocator, ZONE_NAME);
-  WasmFullDecoder decoder(&zone, nullptr, body);
+  WasmFullDecoder decoder(&zone, module, body);
   int line_nr = 0;
 
   // Print the function signature.
@@ -1926,14 +1963,22 @@ bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
   }
 
   // Print the local declarations.
-  AstLocalDecls decls(&zone);
+  BodyLocalDecls decls(&zone);
   BytecodeIterator i(body.start, body.end, &decls);
-  if (body.start != i.pc()) {
+  if (body.start != i.pc() && !FLAG_wasm_code_fuzzer_gen_test) {
     os << "// locals: ";
-    for (auto p : decls.local_types) {
-      LocalType type = p.first;
-      uint32_t count = p.second;
-      os << " " << count << " " << WasmOpcodes::TypeName(type);
+    if (!decls.type_list.empty()) {
+      ValueType type = decls.type_list[0];
+      uint32_t count = 0;
+      for (size_t pos = 0; pos < decls.type_list.size(); ++pos) {
+        if (decls.type_list[pos] == type) {
+          ++count;
+        } else {
+          os << " " << count << " " << WasmOpcodes::TypeName(type);
+          type = decls.type_list[pos];
+          count = 1;
+        }
+      }
     }
     os << std::endl;
     ++line_nr;
@@ -1949,25 +1994,22 @@ bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
   ++line_nr;
   unsigned control_depth = 0;
   for (; i.has_next(); i.next()) {
-    unsigned length = decoder.OpcodeLength(i.pc());
+    unsigned length = WasmDecoder::OpcodeLength(&decoder, i.pc());
 
     WasmOpcode opcode = i.current();
     if (opcode == kExprElse) control_depth--;
 
     int num_whitespaces = control_depth < 32 ? 2 * control_depth : 64;
-    if (offset_table) {
-      offset_table->push_back(
-          std::make_tuple(i.pc_offset(), line_nr, num_whitespaces));
-    }
 
     // 64 whitespaces
     const char* padding =
         "                                                                ";
     os.write(padding, num_whitespaces);
-    os << "k" << WasmOpcodes::OpcodeName(opcode) << ",";
+
+    os << RawOpcodeName(opcode) << ",";
 
     for (size_t j = 1; j < length; ++j) {
-      os << " " << AsHex(i.pc()[j], 2) << ",";
+      os << " 0x" << AsHex(i.pc()[j], 2) << ",";
     }
 
     switch (opcode) {
@@ -2024,7 +2066,7 @@ bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
       }
       default:
         break;
-      }
+    }
     os << std::endl;
     ++line_nr;
   }
@@ -2034,9 +2076,9 @@ bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
 
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
-  FunctionBody body = {nullptr, nullptr, nullptr, start, end};
-  WasmFullDecoder decoder(zone, nullptr, body);
-  return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals);
+  Decoder decoder(start, end);
+  return WasmDecoder::AnalyzeLoopAssignment(&decoder, start,
+                                            static_cast<int>(num_locals), zone);
 }
 
 }  // namespace wasm
diff --git a/deps/v8/src/wasm/ast-decoder.h b/deps/v8/src/wasm/function-body-decoder.h
index 9ce323efcb..1115b1a450 100644
--- a/deps/v8/src/wasm/ast-decoder.h
+++ b/deps/v8/src/wasm/function-body-decoder.h
@@ -2,10 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef V8_WASM_AST_DECODER_H_
-#define V8_WASM_AST_DECODER_H_
+#ifndef V8_WASM_FUNCTION_BODY_DECODER_H_
+#define V8_WASM_FUNCTION_BODY_DECODER_H_
+
+#include <iterator>
 
 #include "src/base/compiler-specific.h"
+#include "src/base/iterator.h"
 #include "src/globals.h"
 #include "src/signature.h"
 #include "src/wasm/decoder.h"
@@ -29,12 +32,12 @@ struct WasmGlobal;
 // Helpers for decoding different kinds of operands which follow bytecodes.
 struct LocalIndexOperand {
   uint32_t index;
-  LocalType type;
+  ValueType type;
   unsigned length;
 
   inline LocalIndexOperand(Decoder* decoder, const byte* pc) {
     index = decoder->checked_read_u32v(pc, 1, &length, "local index");
-    type = kAstStmt;
+    type = kWasmStmt;
   }
 };
 
@@ -67,7 +70,9 @@ struct ImmF32Operand {
   float value;
   unsigned length;
   inline ImmF32Operand(Decoder* decoder, const byte* pc) {
-    value = bit_cast<float>(decoder->checked_read_u32(pc, 1, "immf32"));
+    // Avoid bit_cast because it might not preserve the signalling bit of a NaN.
+    uint32_t tmp = decoder->checked_read_u32(pc, 1, "immf32");
+    memcpy(&value, &tmp, sizeof(value));
     length = 4;
   }
 };
@@ -76,21 +81,23 @@ struct ImmF64Operand {
   double value;
   unsigned length;
   inline ImmF64Operand(Decoder* decoder, const byte* pc) {
-    value = bit_cast<double>(decoder->checked_read_u64(pc, 1, "immf64"));
+    // Avoid bit_cast because it might not preserve the signalling bit of a NaN.
+    uint64_t tmp = decoder->checked_read_u64(pc, 1, "immf64");
+    memcpy(&value, &tmp, sizeof(value));
     length = 8;
   }
 };
 
 struct GlobalIndexOperand {
   uint32_t index;
-  LocalType type;
+  ValueType type;
   const WasmGlobal* global;
   unsigned length;
 
   inline GlobalIndexOperand(Decoder* decoder, const byte* pc) {
     index = decoder->checked_read_u32v(pc, 1, &length, "global index");
     global = nullptr;
-    type = kAstStmt;
+    type = kWasmStmt;
   }
 };
 
@@ -101,12 +108,12 @@ struct BlockTypeOperand {
 
   inline BlockTypeOperand(Decoder* decoder, const byte* pc) {
     uint8_t val = decoder->checked_read_u8(pc, 1, "block type");
-    LocalType type = kAstStmt;
+    ValueType type = kWasmStmt;
     length = 1;
     arity = 0;
     types = nullptr;
     if (decode_local_type(val, &type)) {
-      arity = type == kAstStmt ? 0 : 1;
+      arity = type == kWasmStmt ? 0 : 1;
       types = pc + 1;
     } else {
       // Handle multi-value blocks.
@@ -132,7 +139,7 @@ struct BlockTypeOperand {
         uint32_t offset = 1 + 1 + len + i;
         val = decoder->checked_read_u8(pc, offset, "block type");
         decode_local_type(val, &type);
-        if (type == kAstStmt) {
+        if (type == kWasmStmt) {
           decoder->error(pc, pc + offset, "invalid block type");
           return;
         }
@@ -141,34 +148,34 @@ struct BlockTypeOperand {
   }
   // Decode a byte representing a local type. Return {false} if the encoded
   // byte was invalid or {kMultivalBlock}.
-  bool decode_local_type(uint8_t val, LocalType* result) {
-    switch (static_cast<LocalTypeCode>(val)) {
+  bool decode_local_type(uint8_t val, ValueType* result) {
+    switch (static_cast<ValueTypeCode>(val)) {
       case kLocalVoid:
-        *result = kAstStmt;
+        *result = kWasmStmt;
         return true;
       case kLocalI32:
-        *result = kAstI32;
+        *result = kWasmI32;
         return true;
       case kLocalI64:
-        *result = kAstI64;
+        *result = kWasmI64;
         return true;
       case kLocalF32:
-        *result = kAstF32;
+        *result = kWasmF32;
         return true;
       case kLocalF64:
-        *result = kAstF64;
+        *result = kWasmF64;
         return true;
       case kLocalS128:
-        *result = kAstS128;
+        *result = kWasmS128;
         return true;
       default:
-        *result = kAstStmt;
+        *result = kWasmStmt;
         return false;
     }
   }
-  LocalType read_entry(unsigned index) {
+  ValueType read_entry(unsigned index) {
     DCHECK_LT(index, arity);
-    LocalType result;
+    ValueType result;
     CHECK(decode_local_type(types[index], &result));
     return result;
   }
@@ -243,10 +250,6 @@ struct BranchTableOperand {
     }
     table = pc + 1 + len1;
   }
-  inline uint32_t read_entry(Decoder* decoder, unsigned i) {
-    DCHECK(i <= table_count);
-    return table ? decoder->read_u32(table + i * sizeof(uint32_t)) : 0;
-  }
 };
 
 // A helper to iterate over a branch table.
@@ -309,11 +312,10 @@ struct MemoryAccessOperand {
 };
 
 typedef compiler::WasmGraphBuilder TFBuilder;
-struct ModuleEnv;  // forward declaration of module interface.
+struct WasmModule;  // forward declaration of module interface.
 
 // All of the various data structures necessary to decode a function body.
 struct FunctionBody {
-  ModuleEnv* module;  // module environment
   FunctionSig* sig;   // function signature
   const byte* base;   // base of the module bytes, for error reporting
   const byte* start;  // start of the function body
@@ -322,7 +324,7 @@ struct FunctionBody {
 
 static inline FunctionBody FunctionBodyForTesting(const byte* start,
                                                   const byte* end) {
-  return {nullptr, nullptr, start, start, end};
+  return {nullptr, start, start, end};
 }
 
 struct DecodeStruct {
@@ -334,48 +336,42 @@ inline std::ostream& operator<<(std::ostream& os, const DecodeStruct& tree) {
 }
 
 V8_EXPORT_PRIVATE DecodeResult VerifyWasmCode(AccountingAllocator* allocator,
+                                              const wasm::WasmModule* module,
                                               FunctionBody& body);
 DecodeResult BuildTFGraph(AccountingAllocator* allocator, TFBuilder* builder,
                           FunctionBody& body);
-bool PrintAst(AccountingAllocator* allocator, const FunctionBody& body,
-              std::ostream& os,
-              std::vector<std::tuple<uint32_t, int, int>>* offset_table);
+bool PrintRawWasmCode(AccountingAllocator* allocator, const FunctionBody& body,
+                      const wasm::WasmModule* module);
 
 // A simplified form of AST printing, e.g. from a debugger.
-void PrintAstForDebugging(const byte* start, const byte* end);
+void PrintRawWasmCode(const byte* start, const byte* end);
 
 inline DecodeResult VerifyWasmCode(AccountingAllocator* allocator,
-                                   ModuleEnv* module, FunctionSig* sig,
+                                   const WasmModule* module, FunctionSig* sig,
                                    const byte* start, const byte* end) {
-  FunctionBody body = {module, sig, nullptr, start, end};
-  return VerifyWasmCode(allocator, body);
+  FunctionBody body = {sig, nullptr, start, end};
+  return VerifyWasmCode(allocator, module, body);
 }
 
 inline DecodeResult BuildTFGraph(AccountingAllocator* allocator,
-                                 TFBuilder* builder, ModuleEnv* module,
-                                 FunctionSig* sig, const byte* start,
-                                 const byte* end) {
-  FunctionBody body = {module, sig, nullptr, start, end};
+                                 TFBuilder* builder, FunctionSig* sig,
+                                 const byte* start, const byte* end) {
+  FunctionBody body = {sig, nullptr, start, end};
   return BuildTFGraph(allocator, builder, body);
 }
 
-struct AstLocalDecls {
+struct BodyLocalDecls {
   // The size of the encoded declarations.
-  uint32_t decls_encoded_size;  // size of encoded declarations
+  uint32_t encoded_size;  // size of encoded declarations
 
-  // Total number of locals.
-  uint32_t total_local_count;
-
-  // List of {local type, count} pairs.
-  ZoneVector<std::pair<LocalType, uint32_t>> local_types;
+  ZoneVector<ValueType> type_list;
 
   // Constructor initializes the vector.
-  explicit AstLocalDecls(Zone* zone)
-      : decls_encoded_size(0), total_local_count(0), local_types(zone) {}
+  explicit BodyLocalDecls(Zone* zone) : encoded_size(0), type_list(zone) {}
 };
 
-V8_EXPORT_PRIVATE bool DecodeLocalDecls(AstLocalDecls& decls, const byte* start,
-                                        const byte* end);
+V8_EXPORT_PRIVATE bool DecodeLocalDecls(BodyLocalDecls* decls,
+                                        const byte* start, const byte* end);
 V8_EXPORT_PRIVATE BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone,
                                                              size_t num_locals,
                                                              const byte* start,
@@ -386,41 +382,77 @@ V8_EXPORT_PRIVATE unsigned OpcodeLength(const byte* pc, const byte* end);
 
 // A simple forward iterator for bytecodes.
 class V8_EXPORT_PRIVATE BytecodeIterator : public NON_EXPORTED_BASE(Decoder) {
- public:
-  // If one wants to iterate over the bytecode without looking at {pc_offset()}.
-  class iterator {
+  // Base class for both iterators defined below.
+  class iterator_base {
    public:
-    inline iterator& operator++() {
+    inline iterator_base& operator++() {
       DCHECK_LT(ptr_, end_);
       ptr_ += OpcodeLength(ptr_, end_);
       return *this;
     }
+    inline bool operator==(const iterator_base& that) {
+      return this->ptr_ == that.ptr_;
+    }
+    inline bool operator!=(const iterator_base& that) {
+      return this->ptr_ != that.ptr_;
+    }
+
+   protected:
+    const byte* ptr_;
+    const byte* end_;
+    iterator_base(const byte* ptr, const byte* end) : ptr_(ptr), end_(end) {}
+  };
+
+ public:
+  // If one wants to iterate over the bytecode without looking at {pc_offset()}.
+  class opcode_iterator
+      : public iterator_base,
+        public std::iterator<std::input_iterator_tag, WasmOpcode> {
+   public:
     inline WasmOpcode operator*() {
       DCHECK_LT(ptr_, end_);
       return static_cast<WasmOpcode>(*ptr_);
     }
-    inline bool operator==(const iterator& that) {
-      return this->ptr_ == that.ptr_;
-    }
-    inline bool operator!=(const iterator& that) {
-      return this->ptr_ != that.ptr_;
+
+   private:
+    friend class BytecodeIterator;
+    opcode_iterator(const byte* ptr, const byte* end)
+        : iterator_base(ptr, end) {}
+  };
+  // If one wants to iterate over the instruction offsets without looking at
+  // opcodes.
+  class offset_iterator
+      : public iterator_base,
+        public std::iterator<std::input_iterator_tag, uint32_t> {
+   public:
+    inline uint32_t operator*() {
+      DCHECK_LT(ptr_, end_);
+      return static_cast<uint32_t>(ptr_ - start_);
     }
 
    private:
+    const byte* start_;
     friend class BytecodeIterator;
-    const byte* ptr_;
-    const byte* end_;
-    iterator(const byte* ptr, const byte* end) : ptr_(ptr), end_(end) {}
+    offset_iterator(const byte* start, const byte* ptr, const byte* end)
+        : iterator_base(ptr, end), start_(start) {}
   };
 
   // Create a new {BytecodeIterator}. If the {decls} pointer is non-null,
   // assume the bytecode starts with local declarations and decode them.
   // Otherwise, do not decode local decls.
   BytecodeIterator(const byte* start, const byte* end,
-                   AstLocalDecls* decls = nullptr);
+                   BodyLocalDecls* decls = nullptr);
 
-  inline iterator begin() const { return iterator(pc_, end_); }
-  inline iterator end() const { return iterator(end_, end_); }
+  base::iterator_range<opcode_iterator> opcodes() {
+    return base::iterator_range<opcode_iterator>(opcode_iterator(pc_, end_),
+                                                 opcode_iterator(end_, end_));
+  }
+
+  base::iterator_range<offset_iterator> offsets() {
+    return base::iterator_range<offset_iterator>(
+        offset_iterator(start_, pc_, end_),
+        offset_iterator(start_, end_, end_));
+  }
 
   WasmOpcode current() {
     return static_cast<WasmOpcode>(
@@ -441,4 +473,4 @@ class V8_EXPORT_PRIVATE BytecodeIterator : public NON_EXPORTED_BASE(Decoder) {
 }  // namespace internal
 }  // namespace v8
 
-#endif  // V8_WASM_AST_DECODER_H_
+#endif  // V8_WASM_FUNCTION_BODY_DECODER_H_
diff --git a/deps/v8/src/wasm/module-decoder.cc b/deps/v8/src/wasm/module-decoder.cc
index c8eace3c10..056fc2f64d 100644
--- a/deps/v8/src/wasm/module-decoder.cc
+++ b/deps/v8/src/wasm/module-decoder.cc
@@ -12,6 +12,7 @@
 #include "src/v8.h"
 
 #include "src/wasm/decoder.h"
+#include "src/wasm/wasm-limits.h"
 
 namespace v8 {
 namespace internal {
@@ -31,25 +32,25 @@ namespace {
 const char* kNameString = "name";
 const size_t kNameStringLength = 4;
 
-LocalType TypeOf(const WasmModule* module, const WasmInitExpr& expr) {
+ValueType TypeOf(const WasmModule* module, const WasmInitExpr& expr) {
   switch (expr.kind) {
     case WasmInitExpr::kNone:
-      return kAstStmt;
+      return kWasmStmt;
     case WasmInitExpr::kGlobalIndex:
       return expr.val.global_index < module->globals.size()
                  ? module->globals[expr.val.global_index].type
-                 : kAstStmt;
+                 : kWasmStmt;
     case WasmInitExpr::kI32Const:
-      return kAstI32;
+      return kWasmI32;
     case WasmInitExpr::kI64Const:
-      return kAstI64;
+      return kWasmI64;
     case WasmInitExpr::kF32Const:
-      return kAstF32;
+      return kWasmF32;
     case WasmInitExpr::kF64Const:
-      return kAstF64;
+      return kWasmF64;
     default:
       UNREACHABLE();
-      return kAstStmt;
+      return kWasmStmt;
   }
 }
 
@@ -179,17 +180,17 @@ class ModuleDecoder : public Decoder {
                 ModuleOrigin origin)
       : Decoder(module_start, module_end), module_zone(zone), origin_(origin) {
     result_.start = start_;
-    if (limit_ < start_) {
+    if (end_ < start_) {
       error(start_, "end is less than start");
-      limit_ = start_;
+      end_ = start_;
     }
   }
 
   virtual void onFirstError() {
-    pc_ = limit_;  // On error, terminate section decoding loop.
+    pc_ = end_;  // On error, terminate section decoding loop.
   }
 
-  static void DumpModule(WasmModule* module, const ModuleResult& result) {
+  void DumpModule(const ModuleResult& result) {
     std::string path;
     if (FLAG_dump_wasm_module_path) {
       path = FLAG_dump_wasm_module_path;
@@ -199,7 +200,7 @@ class ModuleDecoder : public Decoder {
       }
     }
     // File are named `HASH.{ok,failed}.wasm`.
-    size_t hash = base::hash_range(module->module_start, module->module_end);
+    size_t hash = base::hash_range(start_, end_);
     char buf[32] = {'\0'};
 #if V8_OS_WIN && _MSC_VER < 1900
 #define snprintf sprintf_s
@@ -208,17 +209,15 @@ class ModuleDecoder : public Decoder {
              result.ok() ? "ok" : "failed");
     std::string name(buf);
     if (FILE* wasm_file = base::OS::FOpen((path + name).c_str(), "wb")) {
-      fwrite(module->module_start, module->module_end - module->module_start, 1,
-             wasm_file);
+      fwrite(start_, end_ - start_, 1, wasm_file);
       fclose(wasm_file);
     }
   }
 
   // Decodes an entire module.
-  ModuleResult DecodeModule(WasmModule* module, bool verify_functions = true) {
+  ModuleResult DecodeModule(bool verify_functions = true) {
     pc_ = start_;
-    module->module_start = start_;
-    module->module_end = limit_;
+    WasmModule* module = new WasmModule(module_zone);
     module->min_mem_pages = 0;
     module->max_mem_pages = 0;
     module->mem_export = false;
@@ -249,8 +248,8 @@ class ModuleDecoder : public Decoder {
 
     // ===== Type section ====================================================
     if (section_iter.section_code() == kTypeSectionCode) {
-      uint32_t signatures_count = consume_u32v("signatures count");
-      module->signatures.reserve(SafeReserve(signatures_count));
+      uint32_t signatures_count = consume_count("types count", kV8MaxWasmTypes);
+      module->signatures.reserve(signatures_count);
       for (uint32_t i = 0; ok() && i < signatures_count; ++i) {
         TRACE("DecodeSignature[%d] module+%d\n", i,
               static_cast<int>(pc_ - start_));
@@ -262,8 +261,9 @@ class ModuleDecoder : public Decoder {
 
     // ===== Import section ==================================================
     if (section_iter.section_code() == kImportSectionCode) {
-      uint32_t import_table_count = consume_u32v("import table count");
-      module->import_table.reserve(SafeReserve(import_table_count));
+      uint32_t import_table_count =
+          consume_count("imports count", kV8MaxWasmImports);
+      module->import_table.reserve(import_table_count);
       for (uint32_t i = 0; ok() && i < import_table_count; ++i) {
         TRACE("DecodeImportTable[%d] module+%d\n", i,
               static_cast<int>(pc_ - start_));
@@ -280,9 +280,6 @@ class ModuleDecoder : public Decoder {
         const byte* pos = pc_;
         import->module_name_offset =
             consume_string(&import->module_name_length, true);
-        if (import->module_name_length == 0) {
-          error(pos, "import module name cannot be NULL");
-        }
         import->field_name_offset =
             consume_string(&import->field_name_length, true);
 
@@ -307,6 +304,7 @@ class ModuleDecoder : public Decoder {
           }
           case kExternalTable: {
             // ===== Imported table ==========================================
+            if (!AddTable(module)) break;
             import->index =
                 static_cast<uint32_t>(module->function_tables.size());
             module->function_tables.push_back({0, 0, false,
@@ -314,30 +312,29 @@ class ModuleDecoder : public Decoder {
                                                false, SignatureMap()});
             expect_u8("element type", kWasmAnyFunctionTypeForm);
             WasmIndirectFunctionTable* table = &module->function_tables.back();
-            consume_resizable_limits(
-                "element count", "elements", WasmModule::kV8MaxTableSize,
-                &table->min_size, &table->has_max, WasmModule::kV8MaxTableSize,
-                &table->max_size);
+            consume_resizable_limits("element count", "elements",
+                                     kV8MaxWasmTableSize, &table->min_size,
+                                     &table->has_max, kV8MaxWasmTableSize,
+                                     &table->max_size);
             break;
           }
           case kExternalMemory: {
             // ===== Imported memory =========================================
-            bool has_max = false;
-            consume_resizable_limits("memory", "pages", WasmModule::kV8MaxPages,
-                                     &module->min_mem_pages, &has_max,
-                                     WasmModule::kSpecMaxPages,
-                                     &module->max_mem_pages);
-            module->has_memory = true;
+            if (!AddMemory(module)) break;
+            consume_resizable_limits(
+                "memory", "pages", kV8MaxWasmMemoryPages,
+                &module->min_mem_pages, &module->has_max_mem,
+                kSpecMaxWasmMemoryPages, &module->max_mem_pages);
             break;
           }
           case kExternalGlobal: {
             // ===== Imported global =========================================
             import->index = static_cast<uint32_t>(module->globals.size());
             module->globals.push_back(
-                {kAstStmt, false, WasmInitExpr(), 0, true, false});
+                {kWasmStmt, false, WasmInitExpr(), 0, true, false});
             WasmGlobal* global = &module->globals.back();
             global->type = consume_value_type();
-            global->mutability = consume_u8("mutability") != 0;
+            global->mutability = consume_mutability();
             if (global->mutability) {
               error("mutable globals cannot be imported");
             }
@@ -353,8 +350,9 @@ class ModuleDecoder : public Decoder {
 
     // ===== Function section ================================================
     if (section_iter.section_code() == kFunctionSectionCode) {
-      uint32_t functions_count = consume_u32v("functions count");
-      module->functions.reserve(SafeReserve(functions_count));
+      uint32_t functions_count =
+          consume_count("functions count", kV8MaxWasmFunctions);
+      module->functions.reserve(functions_count);
       module->num_declared_functions = functions_count;
       for (uint32_t i = 0; ok() && i < functions_count; ++i) {
         uint32_t func_index = static_cast<uint32_t>(module->functions.size());
@@ -375,63 +373,47 @@ class ModuleDecoder : public Decoder {
 
     // ===== Table section ===================================================
     if (section_iter.section_code() == kTableSectionCode) {
-      const byte* pos = pc_;
-      uint32_t table_count = consume_u32v("table count");
-      // Require at most one table for now.
-      if (table_count > 1) {
-        error(pos, pos, "invalid table count %d, maximum 1", table_count);
-      }
-      if (module->function_tables.size() < 1) {
-        module->function_tables.push_back({0, 0, false, std::vector<int32_t>(),
-                                           false, false, SignatureMap()});
-      }
+      uint32_t table_count = consume_count("table count", kV8MaxWasmTables);
 
       for (uint32_t i = 0; ok() && i < table_count; i++) {
+        if (!AddTable(module)) break;
+        module->function_tables.push_back({0, 0, false, std::vector<int32_t>(),
+                                           false, false, SignatureMap()});
         WasmIndirectFunctionTable* table = &module->function_tables.back();
         expect_u8("table type", kWasmAnyFunctionTypeForm);
-        consume_resizable_limits("table elements", "elements",
-                                 WasmModule::kV8MaxTableSize, &table->min_size,
-                                 &table->has_max, WasmModule::kV8MaxTableSize,
-                                 &table->max_size);
+        consume_resizable_limits(
+            "table elements", "elements", kV8MaxWasmTableSize, &table->min_size,
+            &table->has_max, kV8MaxWasmTableSize, &table->max_size);
       }
       section_iter.advance();
     }
 
     // ===== Memory section ==================================================
     if (section_iter.section_code() == kMemorySectionCode) {
-      const byte* pos = pc_;
-      uint32_t memory_count = consume_u32v("memory count");
-      // Require at most one memory for now.
-      if (memory_count > 1) {
-        error(pos, pos, "invalid memory count %d, maximum 1", memory_count);
-      }
+      uint32_t memory_count = consume_count("memory count", kV8MaxWasmMemories);
 
       for (uint32_t i = 0; ok() && i < memory_count; i++) {
-        bool has_max = false;
-        consume_resizable_limits(
-            "memory", "pages", WasmModule::kV8MaxPages, &module->min_mem_pages,
-            &has_max, WasmModule::kSpecMaxPages, &module->max_mem_pages);
+        if (!AddMemory(module)) break;
+        consume_resizable_limits("memory", "pages", kV8MaxWasmMemoryPages,
+                                 &module->min_mem_pages, &module->has_max_mem,
+                                 kSpecMaxWasmMemoryPages,
+                                 &module->max_mem_pages);
       }
-      module->has_memory = true;
       section_iter.advance();
     }
 
     // ===== Global section ==================================================
     if (section_iter.section_code() == kGlobalSectionCode) {
-      uint32_t globals_count = consume_u32v("globals count");
+      uint32_t globals_count =
+          consume_count("globals count", kV8MaxWasmGlobals);
       uint32_t imported_globals = static_cast<uint32_t>(module->globals.size());
-      if (!IsWithinLimit(std::numeric_limits<int32_t>::max(), globals_count,
-                         imported_globals)) {
-        error(pos, pos, "too many imported+defined globals: %u + %u",
-              imported_globals, globals_count);
-      }
-      module->globals.reserve(SafeReserve(imported_globals + globals_count));
+      module->globals.reserve(imported_globals + globals_count);
       for (uint32_t i = 0; ok() && i < globals_count; ++i) {
         TRACE("DecodeGlobal[%d] module+%d\n", i,
               static_cast<int>(pc_ - start_));
         // Add an uninitialized global and pass a pointer to it.
         module->globals.push_back(
-            {kAstStmt, false, WasmInitExpr(), 0, false, false});
+            {kWasmStmt, false, WasmInitExpr(), 0, false, false});
         WasmGlobal* global = &module->globals.back();
         DecodeGlobalInModule(module, i + imported_globals, global);
       }
@@ -440,8 +422,9 @@ class ModuleDecoder : public Decoder {
 
     // ===== Export section ==================================================
     if (section_iter.section_code() == kExportSectionCode) {
-      uint32_t export_table_count = consume_u32v("export table count");
-      module->export_table.reserve(SafeReserve(export_table_count));
+      uint32_t export_table_count =
+          consume_count("exports count", kV8MaxWasmImports);
+      module->export_table.reserve(export_table_count);
       for (uint32_t i = 0; ok() && i < export_table_count; ++i) {
         TRACE("DecodeExportTable[%d] module+%d\n", i,
               static_cast<int>(pc_ - start_));
@@ -473,7 +456,11 @@ class ModuleDecoder : public Decoder {
           }
           case kExternalMemory: {
             uint32_t index = consume_u32v("memory index");
-            if (index != 0) error("invalid memory index != 0");
+            // TODO(titzer): This should become more regular
+            // once we support multiple memories.
+            if (!module->has_memory || index != 0) {
+              error("invalid memory index != 0");
+            }
             module->mem_export = true;
             break;
           }
@@ -493,8 +480,8 @@ class ModuleDecoder : public Decoder {
             break;
         }
       }
-      // Check for duplicate exports.
-      if (ok() && module->export_table.size() > 1) {
+      // Check for duplicate exports (except for asm.js).
+      if (ok() && origin_ != kAsmJsOrigin && module->export_table.size() > 1) {
         std::vector<WasmExport> sorted_exports(module->export_table);
         const byte* base = start_;
         auto cmp_less = [base](const WasmExport& a, const WasmExport& b) {
@@ -538,7 +525,8 @@ class ModuleDecoder : public Decoder {
 
     // ===== Elements section ================================================
     if (section_iter.section_code() == kElementSectionCode) {
-      uint32_t element_count = consume_u32v("element count");
+      uint32_t element_count =
+          consume_count("element count", kV8MaxWasmTableSize);
       for (uint32_t i = 0; ok() && i < element_count; ++i) {
         const byte* pos = pc();
         uint32_t table_index = consume_u32v("table index");
@@ -551,19 +539,18 @@ class ModuleDecoder : public Decoder {
         } else {
           table = &module->function_tables[table_index];
         }
-        WasmInitExpr offset = consume_init_expr(module, kAstI32);
-        uint32_t num_elem = consume_u32v("number of elements");
+        WasmInitExpr offset = consume_init_expr(module, kWasmI32);
+        uint32_t num_elem =
+            consume_count("number of elements", kV8MaxWasmTableEntries);
         std::vector<uint32_t> vector;
         module->table_inits.push_back({table_index, offset, vector});
         WasmTableInit* init = &module->table_inits.back();
-        init->entries.reserve(SafeReserve(num_elem));
         for (uint32_t j = 0; ok() && j < num_elem; j++) {
           WasmFunction* func = nullptr;
           uint32_t index = consume_func_index(module, &func);
           init->entries.push_back(index);
           if (table && index < module->functions.size()) {
             // Canonicalize signature indices during decoding.
-            // TODO(titzer): suboptimal, redundant when verifying only.
             table->map.FindOrInsert(module->functions[index].sig);
           }
         }
@@ -587,10 +574,8 @@ class ModuleDecoder : public Decoder {
         function->code_start_offset = pc_offset();
         function->code_end_offset = pc_offset() + size;
         if (verify_functions) {
-          ModuleEnv module_env;
-          module_env.module = module;
-          module_env.origin = module->origin;
-
+          ModuleBytesEnv module_env(module, nullptr,
+                                    ModuleWireBytes(start_, end_));
           VerifyFunctionBody(i + module->num_imported_functions, &module_env,
                              function);
         }
@@ -601,8 +586,9 @@ class ModuleDecoder : public Decoder {
 
     // ===== Data section ====================================================
     if (section_iter.section_code() == kDataSectionCode) {
-      uint32_t data_segments_count = consume_u32v("data segments count");
-      module->data_segments.reserve(SafeReserve(data_segments_count));
+      uint32_t data_segments_count =
+          consume_count("data segments count", kV8MaxWasmDataSegments);
+      module->data_segments.reserve(data_segments_count);
       for (uint32_t i = 0; ok() && i < data_segments_count; ++i) {
         if (!module->has_memory) {
           error("cannot load data without memory");
@@ -623,22 +609,29 @@ class ModuleDecoder : public Decoder {
 
     // ===== Name section ====================================================
     if (section_iter.section_code() == kNameSectionCode) {
-      uint32_t functions_count = consume_u32v("functions count");
+      // TODO(titzer): find a way to report name errors as warnings.
+      // Use an inner decoder so that errors don't fail the outer decoder.
+      Decoder inner(start_, pc_, end_);
+      uint32_t functions_count = inner.consume_u32v("functions count");
 
-      for (uint32_t i = 0; ok() && i < functions_count; ++i) {
+      for (uint32_t i = 0; inner.ok() && i < functions_count; ++i) {
         uint32_t function_name_length = 0;
-        uint32_t name_offset = consume_string(&function_name_length, false);
+        uint32_t name_offset =
+            consume_string(inner, &function_name_length, false);
         uint32_t func_index = i;
-        if (func_index < module->functions.size()) {
+        if (inner.ok() && func_index < module->functions.size()) {
           module->functions[func_index].name_offset = name_offset;
           module->functions[func_index].name_length = function_name_length;
         }
 
-        uint32_t local_names_count = consume_u32v("local names count");
+        uint32_t local_names_count = inner.consume_u32v("local names count");
         for (uint32_t j = 0; ok() && j < local_names_count; j++) {
-          skip_string();
+          uint32_t length = inner.consume_u32v("string length");
+          inner.consume_bytes(length, "string");
         }
       }
+      // Skip the whole names section in the outer decoder.
+      consume_bytes(section_iter.payload_length(), nullptr);
       section_iter.advance();
     }
 
@@ -656,25 +649,19 @@ class ModuleDecoder : public Decoder {
     if (verify_functions && result.ok()) {
       result.MoveFrom(result_);  // Copy error code and location.
     }
-    if (FLAG_dump_wasm_module) DumpModule(module, result);
+    if (FLAG_dump_wasm_module) DumpModule(result);
     return result;
   }
 
-  uint32_t SafeReserve(uint32_t count) {
-    // Avoid OOM by only reserving up to a certain size.
-    const uint32_t kMaxReserve = 20000;
-    return count < kMaxReserve ? count : kMaxReserve;
-  }
-
   // Decodes a single anonymous function starting at {start_}.
-  FunctionResult DecodeSingleFunction(ModuleEnv* module_env,
+  FunctionResult DecodeSingleFunction(ModuleBytesEnv* module_env,
                                       WasmFunction* function) {
     pc_ = start_;
     function->sig = consume_sig();            // read signature
     function->name_offset = 0;                // ---- name
     function->name_length = 0;                // ---- name length
     function->code_start_offset = off(pc_);   // ---- code start
-    function->code_end_offset = off(limit_);  // ---- code end
+    function->code_end_offset = off(end_);    // ---- code end
 
     if (ok()) VerifyFunctionBody(0, module_env, function);
 
@@ -693,7 +680,7 @@ class ModuleDecoder : public Decoder {
 
   WasmInitExpr DecodeInitExpr(const byte* start) {
     pc_ = start;
-    return consume_init_expr(nullptr, kAstStmt);
+    return consume_init_expr(nullptr, kWasmStmt);
   }
 
  private:
@@ -703,13 +690,32 @@ class ModuleDecoder : public Decoder {
 
   uint32_t off(const byte* ptr) { return static_cast<uint32_t>(ptr - start_); }
 
+  bool AddTable(WasmModule* module) {
+    if (module->function_tables.size() > 0) {
+      error("At most one table is supported");
+      return false;
+    } else {
+      return true;
+    }
+  }
+
+  bool AddMemory(WasmModule* module) {
+    if (module->has_memory) {
+      error("At most one memory is supported");
+      return false;
+    } else {
+      module->has_memory = true;
+      return true;
+    }
+  }
+
   // Decodes a single global entry inside a module starting at {pc_}.
   void DecodeGlobalInModule(WasmModule* module, uint32_t index,
                             WasmGlobal* global) {
     global->type = consume_value_type();
-    global->mutability = consume_u8("mutability") != 0;
+    global->mutability = consume_mutability();
     const byte* pos = pc();
-    global->init = consume_init_expr(module, kAstStmt);
+    global->init = consume_init_expr(module, kWasmStmt);
     switch (global->init.kind) {
       case WasmInitExpr::kGlobalIndex: {
         uint32_t other_index = global->init.val.global_index;
@@ -747,12 +753,12 @@ class ModuleDecoder : public Decoder {
   void DecodeDataSegmentInModule(WasmModule* module, WasmDataSegment* segment) {
     const byte* start = pc_;
     expect_u8("linear memory index", 0);
-    segment->dest_addr = consume_init_expr(module, kAstI32);
+    segment->dest_addr = consume_init_expr(module, kWasmI32);
     segment->source_size = consume_u32v("source size");
     segment->source_offset = static_cast<uint32_t>(pc_ - start_);
 
     // Validate the data is in the module.
-    uint32_t module_limit = static_cast<uint32_t>(limit_ - start_);
+    uint32_t module_limit = static_cast<uint32_t>(end_ - start_);
     if (!IsWithinLimit(module_limit, segment->source_offset,
                        segment->source_size)) {
       error(start, "segment out of bounds of module");
@@ -779,17 +785,19 @@ class ModuleDecoder : public Decoder {
   }
 
   // Verifies the body (code) of a given function.
-  void VerifyFunctionBody(uint32_t func_num, ModuleEnv* menv,
+  void VerifyFunctionBody(uint32_t func_num, ModuleBytesEnv* menv,
                           WasmFunction* function) {
     if (FLAG_trace_wasm_decoder || FLAG_trace_wasm_decode_time) {
       OFStream os(stdout);
       os << "Verifying WASM function " << WasmFunctionName(function, menv)
          << std::endl;
     }
-    FunctionBody body = {menv, function->sig, start_,
+    FunctionBody body = {function->sig, start_,
                          start_ + function->code_start_offset,
                          start_ + function->code_end_offset};
-    DecodeResult result = VerifyWasmCode(module_zone->allocator(), body);
+    DecodeResult result =
+        VerifyWasmCode(module_zone->allocator(),
+                       menv == nullptr ? nullptr : menv->module, body);
     if (result.failed()) {
       // Wrap the error message from the function decoder.
       std::ostringstream str;
@@ -808,27 +816,26 @@ class ModuleDecoder : public Decoder {
     }
   }
 
+  uint32_t consume_string(uint32_t* length, bool validate_utf8) {
+    return consume_string(*this, length, validate_utf8);
+  }
+
   // Reads a length-prefixed string, checking that it is within bounds. Returns
   // the offset of the string, and the length as an out parameter.
-  uint32_t consume_string(uint32_t* length, bool validate_utf8) {
-    *length = consume_u32v("string length");
-    uint32_t offset = pc_offset();
-    const byte* string_start = pc_;
+  uint32_t consume_string(Decoder& decoder, uint32_t* length,
+                          bool validate_utf8) {
+    *length = decoder.consume_u32v("string length");
+    uint32_t offset = decoder.pc_offset();
+    const byte* string_start = decoder.pc();
     // Consume bytes before validation to guarantee that the string is not oob.
-    if (*length > 0) consume_bytes(*length, "string");
-    if (ok() && validate_utf8 &&
+    if (*length > 0) decoder.consume_bytes(*length, "string");
+    if (decoder.ok() && validate_utf8 &&
         !unibrow::Utf8::Validate(string_start, *length)) {
-      error(string_start, "no valid UTF-8 string");
+      decoder.error(string_start, "no valid UTF-8 string");
     }
     return offset;
   }
 
-  // Skips over a length-prefixed string, but checks that it is within bounds.
-  void skip_string() {
-    uint32_t length = consume_u32v("string length");
-    consume_bytes(length, "string");
-  }
-
   uint32_t consume_sig_index(WasmModule* module, FunctionSig** sig) {
     const byte* pos = pc_;
     uint32_t sig_index = consume_u32v("signature index");
@@ -842,6 +849,17 @@ class ModuleDecoder : public Decoder {
     return sig_index;
   }
 
+  uint32_t consume_count(const char* name, size_t maximum) {
+    const byte* p = pc_;
+    uint32_t count = consume_u32v(name);
+    if (count > maximum) {
+      error(p, p, "%s of %u exceeds internal limit of %zu", name, count,
+            maximum);
+      return static_cast<uint32_t>(maximum);
+    }
+    return count;
+  }
+
   uint32_t consume_func_index(WasmModule* module, WasmFunction** func) {
     return consume_index("function index", module->functions, func);
   }
@@ -912,7 +930,7 @@ class ModuleDecoder : public Decoder {
     return true;
   }
 
-  WasmInitExpr consume_init_expr(WasmModule* module, LocalType expected) {
+  WasmInitExpr consume_init_expr(WasmModule* module, ValueType expected) {
     const byte* pos = pc();
     uint8_t opcode = consume_u8("opcode");
     WasmInitExpr expr;
@@ -978,7 +996,7 @@ class ModuleDecoder : public Decoder {
     if (!expect_u8("end opcode", kExprEnd)) {
       expr.kind = WasmInitExpr::kNone;
     }
-    if (expected != kAstStmt && TypeOf(module, expr) != kAstI32) {
+    if (expected != kWasmStmt && TypeOf(module, expr) != kWasmI32) {
       error(pos, pos, "type error in init expression, expected %s, got %s",
             WasmOpcodes::TypeName(expected),
             WasmOpcodes::TypeName(TypeOf(module, expr)));
@@ -986,29 +1004,36 @@ class ModuleDecoder : public Decoder {
     return expr;
   }
 
+  // Read a mutability flag
+  bool consume_mutability() {
+    byte val = consume_u8("mutability");
+    if (val > 1) error(pc_ - 1, "invalid mutability");
+    return val != 0;
+  }
+
   // Reads a single 8-bit integer, interpreting it as a local type.
-  LocalType consume_value_type() {
+  ValueType consume_value_type() {
     byte val = consume_u8("value type");
-    LocalTypeCode t = static_cast<LocalTypeCode>(val);
+    ValueTypeCode t = static_cast<ValueTypeCode>(val);
     switch (t) {
       case kLocalI32:
-        return kAstI32;
+        return kWasmI32;
       case kLocalI64:
-        return kAstI64;
+        return kWasmI64;
       case kLocalF32:
-        return kAstF32;
+        return kWasmF32;
       case kLocalF64:
-        return kAstF64;
+        return kWasmF64;
       case kLocalS128:
         if (origin_ != kAsmJsOrigin && FLAG_wasm_simd_prototype) {
-          return kAstS128;
+          return kWasmS128;
         } else {
           error(pc_ - 1, "invalid local type");
-          return kAstStmt;
+          return kWasmStmt;
         }
       default:
         error(pc_ - 1, "invalid local type");
-        return kAstStmt;
+        return kWasmStmt;
     }
   }
 
@@ -1016,35 +1041,32 @@ class ModuleDecoder : public Decoder {
   FunctionSig* consume_sig() {
     if (!expect_u8("type form", kWasmFunctionTypeForm)) return nullptr;
     // parse parameter types
-    uint32_t param_count = consume_u32v("param count");
-    std::vector<LocalType> params;
+    uint32_t param_count =
+        consume_count("param count", kV8MaxWasmFunctionParams);
+    if (failed()) return nullptr;
+    std::vector<ValueType> params;
     for (uint32_t i = 0; ok() && i < param_count; ++i) {
-      LocalType param = consume_value_type();
+      ValueType param = consume_value_type();
       params.push_back(param);
     }
 
     // parse return types
-    const byte* pt = pc_;
-    uint32_t return_count = consume_u32v("return count");
-    if (return_count > kMaxReturnCount) {
-      error(pt, pt, "return count of %u exceeds maximum of %u", return_count,
-            kMaxReturnCount);
-      return nullptr;
-    }
-    std::vector<LocalType> returns;
+    const size_t max_return_count = FLAG_wasm_mv_prototype
+                                        ? kV8MaxWasmFunctionMultiReturns
+                                        : kV8MaxWasmFunctionReturns;
+    uint32_t return_count = consume_count("return count", max_return_count);
+    if (failed()) return nullptr;
+    std::vector<ValueType> returns;
     for (uint32_t i = 0; ok() && i < return_count; ++i) {
-      LocalType ret = consume_value_type();
+      ValueType ret = consume_value_type();
       returns.push_back(ret);
     }
 
-    if (failed()) {
-      // Decoding failed, return void -> void
-      return new (module_zone) FunctionSig(0, 0, nullptr);
-    }
+    if (failed()) return nullptr;
 
     // FunctionSig stores the return types first.
-    LocalType* buffer =
-        module_zone->NewArray<LocalType>(param_count + return_count);
+    ValueType* buffer =
+        module_zone->NewArray<ValueType>(param_count + return_count);
     uint32_t b = 0;
     for (uint32_t i = 0; i < return_count; ++i) buffer[b++] = returns[i];
     for (uint32_t i = 0; i < param_count; ++i) buffer[b++] = params[i];
@@ -1113,16 +1135,16 @@ ModuleResult DecodeWasmModule(Isolate* isolate, const byte* module_start,
       isolate->counters()->wasm_decode_module_time());
   size_t size = module_end - module_start;
   if (module_start > module_end) return ModuleError("start > end");
-  if (size >= kMaxModuleSize) return ModuleError("size > maximum module size");
+  if (size >= kV8MaxWasmModuleSize)
+    return ModuleError("size > maximum module size");
   // TODO(bradnelson): Improve histogram handling of size_t.
   isolate->counters()->wasm_module_size_bytes()->AddSample(
       static_cast<int>(size));
   // Signatures are stored in zone memory, which have the same lifetime
   // as the {module}.
   Zone* zone = new Zone(isolate->allocator(), ZONE_NAME);
-  WasmModule* module = new WasmModule(zone, module_start);
   ModuleDecoder decoder(zone, module_start, module_end, origin);
-  ModuleResult result = decoder.DecodeModule(module, verify_functions);
+  ModuleResult result = decoder.DecodeModule(verify_functions);
   // TODO(bradnelson): Improve histogram handling of size_t.
   // TODO(titzer): this isn't accurate, since it doesn't count the data
   // allocated on the C++ heap.
@@ -1146,14 +1168,14 @@ WasmInitExpr DecodeWasmInitExprForTesting(const byte* start, const byte* end) {
 }
 
 FunctionResult DecodeWasmFunction(Isolate* isolate, Zone* zone,
-                                  ModuleEnv* module_env,
+                                  ModuleBytesEnv* module_env,
                                   const byte* function_start,
                                   const byte* function_end) {
   HistogramTimerScope wasm_decode_function_time_scope(
       isolate->counters()->wasm_decode_function_time());
   size_t size = function_end - function_start;
   if (function_start > function_end) return FunctionError("start > end");
-  if (size > kMaxFunctionSize)
+  if (size > kV8MaxWasmFunctionSize)
     return FunctionError("size > maximum function size");
   isolate->counters()->wasm_function_size_bytes()->AddSample(
       static_cast<int>(size));
@@ -1208,22 +1230,31 @@ AsmJsOffsetsResult DecodeAsmJsOffsets(const byte* tables_start,
   for (uint32_t i = 0; i < functions_count && decoder.ok(); ++i) {
     uint32_t size = decoder.consume_u32v("table size");
     if (size == 0) {
-      table.push_back(std::vector<std::pair<int, int>>());
+      table.push_back(std::vector<AsmJsOffsetEntry>());
       continue;
     }
     if (!decoder.checkAvailable(size)) {
       decoder.error("illegal asm function offset table size");
     }
     const byte* table_end = decoder.pc() + size;
-    uint32_t locals_size = decoder.consume_u32("locals size");
+    uint32_t locals_size = decoder.consume_u32v("locals size");
+    int function_start_position = decoder.consume_u32v("function start pos");
     int last_byte_offset = locals_size;
-    int last_asm_position = 0;
-    std::vector<std::pair<int, int>> func_asm_offsets;
+    int last_asm_position = function_start_position;
+    std::vector<AsmJsOffsetEntry> func_asm_offsets;
     func_asm_offsets.reserve(size / 4);  // conservative estimation
+    // Add an entry for the stack check, associated with position 0.
+    func_asm_offsets.push_back(
+        {0, function_start_position, function_start_position});
     while (decoder.ok() && decoder.pc() < table_end) {
       last_byte_offset += decoder.consume_u32v("byte offset delta");
-      last_asm_position += decoder.consume_i32v("asm position delta");
-      func_asm_offsets.push_back({last_byte_offset, last_asm_position});
+      int call_position =
+          last_asm_position + decoder.consume_i32v("call position delta");
+      int to_number_position =
+          call_position + decoder.consume_i32v("to_number position delta");
+      last_asm_position = to_number_position;
+      func_asm_offsets.push_back(
+          {last_byte_offset, call_position, to_number_position});
     }
     if (decoder.pc() != table_end) {
       decoder.error("broken asm offset table");
@@ -1235,6 +1266,36 @@ AsmJsOffsetsResult DecodeAsmJsOffsets(const byte* tables_start,
   return decoder.toResult(std::move(table));
 }
 
+std::vector<CustomSectionOffset> DecodeCustomSections(const byte* start,
+                                                      const byte* end) {
+  Decoder decoder(start, end);
+  decoder.consume_bytes(4, "wasm magic");
+  decoder.consume_bytes(4, "wasm version");
+
+  std::vector<CustomSectionOffset> result;
+
+  while (decoder.more()) {
+    byte section_code = decoder.consume_u8("section code");
+    uint32_t section_length = decoder.consume_u32v("section length");
+    uint32_t section_start = decoder.pc_offset();
+    if (section_code != 0) {
+      // Skip known sections.
+      decoder.consume_bytes(section_length, "section bytes");
+      continue;
+    }
+    uint32_t name_length = decoder.consume_u32v("name length");
+    uint32_t name_offset = decoder.pc_offset();
+    decoder.consume_bytes(name_length, "section name");
+    uint32_t payload_offset = decoder.pc_offset();
+    uint32_t payload_length = section_length - (payload_offset - section_start);
+    decoder.consume_bytes(payload_length);
+    result.push_back({section_start, name_offset, name_length, payload_offset,
+                      payload_length, section_length});
+  }
+
+  return result;
+}
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
diff --git a/deps/v8/src/wasm/module-decoder.h b/deps/v8/src/wasm/module-decoder.h
index 7cf5cfe3c1..982fbc9189 100644
--- a/deps/v8/src/wasm/module-decoder.h
+++ b/deps/v8/src/wasm/module-decoder.h
@@ -6,7 +6,7 @@
 #define V8_WASM_MODULE_DECODER_H_
 
 #include "src/globals.h"
-#include "src/wasm/ast-decoder.h"
+#include "src/wasm/function-body-decoder.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-result.h"
 
@@ -18,7 +18,12 @@ typedef Result<const WasmModule*> ModuleResult;
 typedef Result<WasmFunction*> FunctionResult;
 typedef std::vector<std::pair<int, int>> FunctionOffsets;
 typedef Result<FunctionOffsets> FunctionOffsetsResult;
-typedef std::vector<std::vector<std::pair<int, int>>> AsmJsOffsets;
+struct AsmJsOffsetEntry {
+  int byte_offset;
+  int source_position_call;
+  int source_position_number_conversion;
+};
+typedef std::vector<std::vector<AsmJsOffsetEntry>> AsmJsOffsets;
 typedef Result<AsmJsOffsets> AsmJsOffsetsResult;
 
 // Decodes the bytes of a WASM module between {module_start} and {module_end}.
@@ -37,7 +42,8 @@ V8_EXPORT_PRIVATE FunctionSig* DecodeWasmSignatureForTesting(Zone* zone,
 // Decodes the bytes of a WASM function between
 // {function_start} and {function_end}.
 V8_EXPORT_PRIVATE FunctionResult DecodeWasmFunction(Isolate* isolate,
-                                                    Zone* zone, ModuleEnv* env,
+                                                    Zone* zone,
+                                                    ModuleBytesEnv* env,
                                                     const byte* function_start,
                                                     const byte* function_end);
 
@@ -50,6 +56,18 @@ FunctionOffsetsResult DecodeWasmFunctionOffsets(const byte* module_start,
 V8_EXPORT_PRIVATE WasmInitExpr DecodeWasmInitExprForTesting(const byte* start,
                                                             const byte* end);
 
+struct CustomSectionOffset {
+  uint32_t section_start;
+  uint32_t name_offset;
+  uint32_t name_length;
+  uint32_t payload_offset;
+  uint32_t payload_length;
+  uint32_t section_length;
+};
+
+V8_EXPORT_PRIVATE std::vector<CustomSectionOffset> DecodeCustomSections(
+    const byte* start, const byte* end);
+
 // Extracts the mapping from wasm byte offset to asm.js source position per
 // function.
 // Returns a vector of vectors with <byte_offset, source_position> entries, or
diff --git a/deps/v8/src/wasm/wasm-debug.cc b/deps/v8/src/wasm/wasm-debug.cc
index 11c2ef8aa5..6cb865d59c 100644
--- a/deps/v8/src/wasm/wasm-debug.cc
+++ b/deps/v8/src/wasm/wasm-debug.cc
@@ -2,144 +2,273 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "src/assembler-inl.h"
 #include "src/assert-scope.h"
+#include "src/compiler/wasm-compiler.h"
 #include "src/debug/debug.h"
 #include "src/factory.h"
+#include "src/frames-inl.h"
 #include "src/isolate.h"
 #include "src/wasm/module-decoder.h"
+#include "src/wasm/wasm-interpreter.h"
+#include "src/wasm/wasm-limits.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-objects.h"
+#include "src/zone/accounting-allocator.h"
 
 using namespace v8::internal;
 using namespace v8::internal::wasm;
 
 namespace {
 
-enum {
-  kWasmDebugInfoWasmObj,
-  kWasmDebugInfoWasmBytesHash,
-  kWasmDebugInfoAsmJsOffsets,
-  kWasmDebugInfoNumEntries
-};
+class InterpreterHandle {
+  AccountingAllocator allocator_;
+  WasmInstance instance_;
+  WasmInterpreter interpreter_;
 
-// TODO(clemensh): Move asm.js offset tables to the compiled module.
-FixedArray *GetAsmJsOffsetTables(Handle<WasmDebugInfo> debug_info,
-                                 Isolate *isolate) {
-  Object *offset_tables = debug_info->get(kWasmDebugInfoAsmJsOffsets);
-  if (!offset_tables->IsUndefined(isolate)) {
-    return FixedArray::cast(offset_tables);
+ public:
+  // Initialize in the right order, using helper methods to make this possible.
+  // WasmInterpreter has to be allocated in place, since it is not movable.
+  InterpreterHandle(Isolate* isolate, WasmDebugInfo* debug_info)
+      : instance_(debug_info->wasm_instance()->compiled_module()->module()),
+        interpreter_(GetBytesEnv(&instance_, debug_info), &allocator_) {
+    Handle<JSArrayBuffer> mem_buffer =
+        handle(debug_info->wasm_instance()->memory_buffer(), isolate);
+    if (mem_buffer->IsUndefined(isolate)) {
+      DCHECK_EQ(0, instance_.module->min_mem_pages);
+      instance_.mem_start = nullptr;
+      instance_.mem_size = 0;
+    } else {
+      instance_.mem_start =
+          reinterpret_cast<byte*>(mem_buffer->backing_store());
+      CHECK(mem_buffer->byte_length()->ToUint32(&instance_.mem_size));
+    }
   }
 
-  Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
-  Handle<WasmCompiledModule> compiled_module(GetCompiledModule(*wasm_instance),
-                                             isolate);
-  DCHECK(compiled_module->has_asm_js_offset_tables());
-
-  AsmJsOffsetsResult asm_offsets;
-  {
-    Handle<ByteArray> asm_offset_tables =
-        compiled_module->asm_js_offset_tables();
-    DisallowHeapAllocation no_gc;
-    const byte *bytes_start = asm_offset_tables->GetDataStartAddress();
-    const byte *bytes_end = bytes_start + asm_offset_tables->length();
-    asm_offsets = wasm::DecodeAsmJsOffsets(bytes_start, bytes_end);
+  static ModuleBytesEnv GetBytesEnv(WasmInstance* instance,
+                                    WasmDebugInfo* debug_info) {
+    // Return raw pointer into heap. The WasmInterpreter will make its own copy
+    // of this data anyway, and there is no heap allocation in-between.
+    SeqOneByteString* bytes_str =
+        debug_info->wasm_instance()->compiled_module()->module_bytes();
+    Vector<const byte> bytes(bytes_str->GetChars(), bytes_str->length());
+    return ModuleBytesEnv(instance->module, instance, bytes);
   }
-  // Wasm bytes must be valid and must contain asm.js offset table.
-  DCHECK(asm_offsets.ok());
-  DCHECK_GE(static_cast<size_t>(kMaxInt), asm_offsets.val.size());
-  int num_functions = static_cast<int>(asm_offsets.val.size());
-  DCHECK_EQ(
-      wasm::GetNumberOfFunctions(handle(debug_info->wasm_instance())),
-      static_cast<int>(num_functions +
-                       compiled_module->module()->num_imported_functions));
-  Handle<FixedArray> all_tables =
-      isolate->factory()->NewFixedArray(num_functions);
-  debug_info->set(kWasmDebugInfoAsmJsOffsets, *all_tables);
-  for (int func = 0; func < num_functions; ++func) {
-    std::vector<std::pair<int, int>> &func_asm_offsets = asm_offsets.val[func];
-    if (func_asm_offsets.empty()) continue;
-    size_t array_size = 2 * kIntSize * func_asm_offsets.size();
-    CHECK_LE(array_size, static_cast<size_t>(kMaxInt));
-    ByteArray *arr =
-        *isolate->factory()->NewByteArray(static_cast<int>(array_size));
-    all_tables->set(func, arr);
-    int idx = 0;
-    for (std::pair<int, int> p : func_asm_offsets) {
-      // Byte offsets must be strictly monotonously increasing:
-      DCHECK(idx == 0 || p.first > arr->get_int(idx - 2));
-      arr->set_int(idx++, p.first);
-      arr->set_int(idx++, p.second);
+
+  WasmInterpreter* interpreter() { return &interpreter_; }
+  const WasmModule* module() { return instance_.module; }
+
+  void Execute(uint32_t func_index, uint8_t* arg_buffer) {
+    DCHECK_GE(module()->functions.size(), func_index);
+    FunctionSig* sig = module()->functions[func_index].sig;
+    DCHECK_GE(kMaxInt, sig->parameter_count());
+    int num_params = static_cast<int>(sig->parameter_count());
+    ScopedVector<WasmVal> wasm_args(num_params);
+    uint8_t* arg_buf_ptr = arg_buffer;
+    for (int i = 0; i < num_params; ++i) {
+      uint32_t param_size = 1 << ElementSizeLog2Of(sig->GetParam(i));
+#define CASE_ARG_TYPE(type, ctype)                                  \
+  case type:                                                        \
+    DCHECK_EQ(param_size, sizeof(ctype));                           \
+    wasm_args[i] = WasmVal(*reinterpret_cast<ctype*>(arg_buf_ptr)); \
+    break;
+      switch (sig->GetParam(i)) {
+        CASE_ARG_TYPE(kWasmI32, uint32_t)
+        CASE_ARG_TYPE(kWasmI64, uint64_t)
+        CASE_ARG_TYPE(kWasmF32, float)
+        CASE_ARG_TYPE(kWasmF64, double)
+#undef CASE_ARG_TYPE
+        default:
+          UNREACHABLE();
+      }
+      arg_buf_ptr += param_size;
     }
-    DCHECK_EQ(arr->length(), idx * kIntSize);
+
+    WasmInterpreter::Thread* thread = interpreter_.GetThread(0);
+    // We do not support reentering an already running interpreter at the moment
+    // (like INTERPRETER -> JS -> WASM -> INTERPRETER).
+    DCHECK(thread->state() == WasmInterpreter::STOPPED ||
+           thread->state() == WasmInterpreter::FINISHED);
+    thread->Reset();
+    thread->PushFrame(&module()->functions[func_index], wasm_args.start());
+    WasmInterpreter::State state;
+    do {
+      state = thread->Run();
+      switch (state) {
+        case WasmInterpreter::State::PAUSED: {
+          // We hit a breakpoint.
+          // TODO(clemensh): Handle this.
+        } break;
+        case WasmInterpreter::State::FINISHED:
+          // Perfect, just break the switch and exit the loop.
+          break;
+        case WasmInterpreter::State::TRAPPED:
+          // TODO(clemensh): Generate appropriate JS exception.
+          UNIMPLEMENTED();
+          break;
+        // STOPPED and RUNNING should never occur here.
+        case WasmInterpreter::State::STOPPED:
+        case WasmInterpreter::State::RUNNING:
+        default:
+          UNREACHABLE();
+      }
+    } while (state != WasmInterpreter::State::FINISHED);
+
+    // Copy back the return value
+    DCHECK_GE(kV8MaxWasmFunctionReturns, sig->return_count());
+    // TODO(wasm): Handle multi-value returns.
+    DCHECK_EQ(1, kV8MaxWasmFunctionReturns);
+    if (sig->return_count()) {
+      WasmVal ret_val = thread->GetReturnValue(0);
+#define CASE_RET_TYPE(type, ctype)                                       \
+  case type:                                                             \
+    DCHECK_EQ(1 << ElementSizeLog2Of(sig->GetReturn(0)), sizeof(ctype)); \
+    *reinterpret_cast<ctype*>(arg_buffer) = ret_val.to<ctype>();         \
+    break;
+      switch (sig->GetReturn(0)) {
+        CASE_RET_TYPE(kWasmI32, uint32_t)
+        CASE_RET_TYPE(kWasmI64, uint64_t)
+        CASE_RET_TYPE(kWasmF32, float)
+        CASE_RET_TYPE(kWasmF64, double)
+#undef CASE_RET_TYPE
+        default:
+          UNREACHABLE();
+      }
+    }
+  }
+};
+
+InterpreterHandle* GetOrCreateInterpreterHandle(
+    Isolate* isolate, Handle<WasmDebugInfo> debug_info) {
+  Handle<Object> handle(debug_info->get(WasmDebugInfo::kInterpreterHandle),
+                        isolate);
+  if (handle->IsUndefined(isolate)) {
+    InterpreterHandle* cpp_handle = new InterpreterHandle(isolate, *debug_info);
+    handle = Managed<InterpreterHandle>::New(isolate, cpp_handle);
+    debug_info->set(WasmDebugInfo::kInterpreterHandle, *handle);
   }
-  return *all_tables;
+
+  return Handle<Managed<InterpreterHandle>>::cast(handle)->get();
+}
+
+int GetNumFunctions(WasmInstanceObject* instance) {
+  size_t num_functions =
+      instance->compiled_module()->module()->functions.size();
+  DCHECK_GE(kMaxInt, num_functions);
+  return static_cast<int>(num_functions);
+}
+
+Handle<FixedArray> GetOrCreateInterpretedFunctions(
+    Isolate* isolate, Handle<WasmDebugInfo> debug_info) {
+  Handle<Object> obj(debug_info->get(WasmDebugInfo::kInterpretedFunctions),
+                     isolate);
+  if (!obj->IsUndefined(isolate)) return Handle<FixedArray>::cast(obj);
+
+  Handle<FixedArray> new_arr = isolate->factory()->NewFixedArray(
+      GetNumFunctions(debug_info->wasm_instance()));
+  debug_info->set(WasmDebugInfo::kInterpretedFunctions, *new_arr);
+  return new_arr;
 }
-}  // namespace
 
-Handle<WasmDebugInfo> WasmDebugInfo::New(Handle<JSObject> wasm) {
-  Isolate *isolate = wasm->GetIsolate();
-  Factory *factory = isolate->factory();
-  Handle<FixedArray> arr =
-      factory->NewFixedArray(kWasmDebugInfoNumEntries, TENURED);
-  arr->set(kWasmDebugInfoWasmObj, *wasm);
-  int hash = 0;
-  Handle<SeqOneByteString> wasm_bytes = GetWasmBytes(wasm);
-  {
-    DisallowHeapAllocation no_gc;
-    hash = StringHasher::HashSequentialString(
-        wasm_bytes->GetChars(), wasm_bytes->length(), kZeroHashSeed);
+void RedirectCallsitesInCode(Code* code, Code* old_target, Code* new_target) {
+  DisallowHeapAllocation no_gc;
+  for (RelocIterator it(code, RelocInfo::kCodeTargetMask); !it.done();
+       it.next()) {
+    DCHECK(RelocInfo::IsCodeTarget(it.rinfo()->rmode()));
+    Code* target = Code::GetCodeFromTargetAddress(it.rinfo()->target_address());
+    if (target != old_target) continue;
+    it.rinfo()->set_target_address(new_target->instruction_start());
   }
-  Handle<Object> hash_obj = factory->NewNumberFromInt(hash, TENURED);
-  arr->set(kWasmDebugInfoWasmBytesHash, *hash_obj);
+}
+
+void RedirectCallsitesInInstance(Isolate* isolate, WasmInstanceObject* instance,
+                                 Code* old_target, Code* new_target) {
+  DisallowHeapAllocation no_gc;
+  // Redirect all calls in wasm functions.
+  FixedArray* code_table = instance->compiled_module()->ptr_to_code_table();
+  for (int i = 0, e = GetNumFunctions(instance); i < e; ++i) {
+    RedirectCallsitesInCode(Code::cast(code_table->get(i)), old_target,
+                            new_target);
+  }
+
+  // Redirect all calls in exported functions.
+  FixedArray* weak_exported_functions =
+      instance->compiled_module()->ptr_to_weak_exported_functions();
+  for (int i = 0, e = weak_exported_functions->length(); i != e; ++i) {
+    WeakCell* weak_function = WeakCell::cast(weak_exported_functions->get(i));
+    if (weak_function->cleared()) continue;
+    Code* code = JSFunction::cast(weak_function->value())->code();
+    RedirectCallsitesInCode(code, old_target, new_target);
+  }
+}
+
+void EnsureRedirectToInterpreter(Isolate* isolate,
+                                 Handle<WasmDebugInfo> debug_info,
+                                 int func_index) {
+  Handle<FixedArray> interpreted_functions =
+      GetOrCreateInterpretedFunctions(isolate, debug_info);
+  if (!interpreted_functions->get(func_index)->IsUndefined(isolate)) return;
+
+  Handle<WasmInstanceObject> instance(debug_info->wasm_instance(), isolate);
+  Handle<Code> new_code = compiler::CompileWasmInterpreterEntry(
+      isolate, func_index,
+      instance->compiled_module()->module()->functions[func_index].sig,
+      instance);
+
+  Handle<FixedArray> code_table = instance->compiled_module()->code_table();
+  Handle<Code> old_code(Code::cast(code_table->get(func_index)), isolate);
+  interpreted_functions->set(func_index, *new_code);
 
+  RedirectCallsitesInInstance(isolate, *instance, *old_code, *new_code);
+}
+
+}  // namespace
+
+Handle<WasmDebugInfo> WasmDebugInfo::New(Handle<WasmInstanceObject> instance) {
+  Isolate* isolate = instance->GetIsolate();
+  Factory* factory = isolate->factory();
+  Handle<FixedArray> arr = factory->NewFixedArray(kFieldCount, TENURED);
+  arr->set(kInstance, *instance);
   return Handle<WasmDebugInfo>::cast(arr);
 }
 
-bool WasmDebugInfo::IsDebugInfo(Object *object) {
+bool WasmDebugInfo::IsDebugInfo(Object* object) {
   if (!object->IsFixedArray()) return false;
-  FixedArray *arr = FixedArray::cast(object);
-  return arr->length() == kWasmDebugInfoNumEntries &&
-         IsWasmInstance(arr->get(kWasmDebugInfoWasmObj)) &&
-         arr->get(kWasmDebugInfoWasmBytesHash)->IsNumber();
+  FixedArray* arr = FixedArray::cast(object);
+  if (arr->length() != kFieldCount) return false;
+  if (!IsWasmInstance(arr->get(kInstance))) return false;
+  Isolate* isolate = arr->GetIsolate();
+  if (!arr->get(kInterpreterHandle)->IsUndefined(isolate) &&
+      !arr->get(kInterpreterHandle)->IsForeign())
+    return false;
+  return true;
 }
 
-WasmDebugInfo *WasmDebugInfo::cast(Object *object) {
+WasmDebugInfo* WasmDebugInfo::cast(Object* object) {
   DCHECK(IsDebugInfo(object));
-  return reinterpret_cast<WasmDebugInfo *>(object);
+  return reinterpret_cast<WasmDebugInfo*>(object);
 }
 
-JSObject *WasmDebugInfo::wasm_instance() {
-  return JSObject::cast(get(kWasmDebugInfoWasmObj));
+WasmInstanceObject* WasmDebugInfo::wasm_instance() {
+  return WasmInstanceObject::cast(get(kInstance));
 }
 
-int WasmDebugInfo::GetAsmJsSourcePosition(Handle<WasmDebugInfo> debug_info,
-                                          int func_index, int byte_offset) {
-  Isolate *isolate = debug_info->GetIsolate();
-  Handle<JSObject> instance(debug_info->wasm_instance(), isolate);
-  FixedArray *offset_tables = GetAsmJsOffsetTables(debug_info, isolate);
-
-  WasmCompiledModule *compiled_module = wasm::GetCompiledModule(*instance);
-  int num_imported_functions =
-      compiled_module->module()->num_imported_functions;
-  DCHECK_LE(num_imported_functions, func_index);
-  func_index -= num_imported_functions;
-  DCHECK_LT(func_index, offset_tables->length());
-  ByteArray *offset_table = ByteArray::cast(offset_tables->get(func_index));
-
-  // Binary search for the current byte offset.
-  int left = 0;                                       // inclusive
-  int right = offset_table->length() / kIntSize / 2;  // exclusive
-  DCHECK_LT(left, right);
-  while (right - left > 1) {
-    int mid = left + (right - left) / 2;
-    if (offset_table->get_int(2 * mid) <= byte_offset) {
-      left = mid;
-    } else {
-      right = mid;
-    }
-  }
-  // There should be an entry for each position that could show up on the stack
-  // trace:
-  DCHECK_EQ(byte_offset, offset_table->get_int(2 * left));
-  return offset_table->get_int(2 * left + 1);
+void WasmDebugInfo::SetBreakpoint(Handle<WasmDebugInfo> debug_info,
+                                  int func_index, int offset) {
+  Isolate* isolate = debug_info->GetIsolate();
+  InterpreterHandle* handle = GetOrCreateInterpreterHandle(isolate, debug_info);
+  WasmInterpreter* interpreter = handle->interpreter();
+  DCHECK_LE(0, func_index);
+  DCHECK_GT(handle->module()->functions.size(), func_index);
+  const WasmFunction* func = &handle->module()->functions[func_index];
+  interpreter->SetBreakpoint(func, offset, true);
+  EnsureRedirectToInterpreter(isolate, debug_info, func_index);
+}
+
+void WasmDebugInfo::RunInterpreter(Handle<WasmDebugInfo> debug_info,
+                                   int func_index, uint8_t* arg_buffer) {
+  DCHECK_LE(0, func_index);
+  InterpreterHandle* interp_handle =
+      GetOrCreateInterpreterHandle(debug_info->GetIsolate(), debug_info);
+  interp_handle->Execute(static_cast<uint32_t>(func_index), arg_buffer);
 }
diff --git a/deps/v8/src/wasm/wasm-external-refs.cc b/deps/v8/src/wasm/wasm-external-refs.cc
index 4c4c91b29c..e982cc7f99 100644
--- a/deps/v8/src/wasm/wasm-external-refs.cc
+++ b/deps/v8/src/wasm/wasm-external-refs.cc
@@ -208,6 +208,19 @@ void float64_pow_wrapper(double* param0, double* param1) {
   double y = ReadDoubleValue(param1);
   WriteDoubleValue(param0, Pow(x, y));
 }
+
+static WasmTrapCallbackForTesting wasm_trap_callback_for_testing = nullptr;
+
+void set_trap_callback_for_testing(WasmTrapCallbackForTesting callback) {
+  wasm_trap_callback_for_testing = callback;
+}
+
+void call_trap_callback_for_testing() {
+  if (wasm_trap_callback_for_testing) {
+    wasm_trap_callback_for_testing();
+  }
+}
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
diff --git a/deps/v8/src/wasm/wasm-external-refs.h b/deps/v8/src/wasm/wasm-external-refs.h
index d9539ce71a..04337b99ec 100644
--- a/deps/v8/src/wasm/wasm-external-refs.h
+++ b/deps/v8/src/wasm/wasm-external-refs.h
@@ -61,6 +61,12 @@ uint32_t word64_popcnt_wrapper(uint64_t* input);
 
 void float64_pow_wrapper(double* param0, double* param1);
 
+typedef void (*WasmTrapCallbackForTesting)();
+
+void set_trap_callback_for_testing(WasmTrapCallbackForTesting callback);
+
+void call_trap_callback_for_testing();
+
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8
diff --git a/deps/v8/src/wasm/wasm-interpreter.cc b/deps/v8/src/wasm/wasm-interpreter.cc
index 6e049ffd25..ac125caf7e 100644
--- a/deps/v8/src/wasm/wasm-interpreter.cc
+++ b/deps/v8/src/wasm/wasm-interpreter.cc
@@ -5,9 +5,10 @@
 #include "src/wasm/wasm-interpreter.h"
 
 #include "src/utils.h"
-#include "src/wasm/ast-decoder.h"
 #include "src/wasm/decoder.h"
+#include "src/wasm/function-body-decoder.h"
 #include "src/wasm/wasm-external-refs.h"
+#include "src/wasm/wasm-limits.h"
 #include "src/wasm/wasm-module.h"
 
 #include "src/zone/accounting-allocator.h"
@@ -62,6 +63,7 @@ namespace wasm {
   V(I64GtS, int64_t, >)         \
   V(I64GeS, int64_t, >=)        \
   V(F32Add, float, +)           \
+  V(F32Sub, float, -)           \
   V(F32Eq, float, ==)           \
   V(F32Ne, float, !=)           \
   V(F32Lt, float, <)            \
@@ -69,6 +71,7 @@ namespace wasm {
   V(F32Gt, float, >)            \
   V(F32Ge, float, >=)           \
   V(F64Add, double, +)          \
+  V(F64Sub, double, -)          \
   V(F64Eq, double, ==)          \
   V(F64Ne, double, !=)          \
   V(F64Lt, double, <)           \
@@ -101,13 +104,11 @@ namespace wasm {
   V(I32Rol, int32_t)           \
   V(I64Ror, int64_t)           \
   V(I64Rol, int64_t)           \
-  V(F32Sub, float)             \
   V(F32Min, float)             \
   V(F32Max, float)             \
   V(F32CopySign, float)        \
   V(F64Min, double)            \
   V(F64Max, double)            \
-  V(F64Sub, double)            \
   V(F64CopySign, double)       \
   V(I32AsmjsDivS, int32_t)     \
   V(I32AsmjsDivU, uint32_t)    \
@@ -158,8 +159,6 @@ namespace wasm {
   V(F64UConvertI64, uint64_t)    \
   V(F64ConvertF32, float)        \
   V(F64ReinterpretI64, int64_t)  \
-  V(I32ReinterpretF32, float)    \
-  V(I64ReinterpretF64, double)   \
   V(I32AsmjsSConvertF32, float)  \
   V(I32AsmjsUConvertF32, float)  \
   V(I32AsmjsSConvertF64, double) \
@@ -293,41 +292,6 @@ static inline uint64_t ExecuteI64Rol(uint64_t a, uint64_t b, TrapReason* trap) {
   return (a << shift) | (a >> (64 - shift));
 }
 
-static float quiet(float a) {
-  static const uint32_t kSignalingBit = 1 << 22;
-  uint32_t q = bit_cast<uint32_t>(std::numeric_limits<float>::quiet_NaN());
-  if ((q & kSignalingBit) != 0) {
-    // On some machines, the signaling bit set indicates it's a quiet NaN.
-    return bit_cast<float>(bit_cast<uint32_t>(a) | kSignalingBit);
-  } else {
-    // On others, the signaling bit set indicates it's a signaling NaN.
-    return bit_cast<float>(bit_cast<uint32_t>(a) & ~kSignalingBit);
-  }
-}
-
-static double quiet(double a) {
-  static const uint64_t kSignalingBit = 1ULL << 51;
-  uint64_t q = bit_cast<uint64_t>(std::numeric_limits<double>::quiet_NaN());
-  if ((q & kSignalingBit) != 0) {
-    // On some machines, the signaling bit set indicates it's a quiet NaN.
-    return bit_cast<double>(bit_cast<uint64_t>(a) | kSignalingBit);
-  } else {
-    // On others, the signaling bit set indicates it's a signaling NaN.
-    return bit_cast<double>(bit_cast<uint64_t>(a) & ~kSignalingBit);
-  }
-}
-
-static inline float ExecuteF32Sub(float a, float b, TrapReason* trap) {
-  float result = a - b;
-  // Some architectures (e.g. MIPS) need extra checking to preserve the payload
-  // of a NaN operand.
-  if (result - result != 0) {
-    if (std::isnan(a)) return quiet(a);
-    if (std::isnan(b)) return quiet(b);
-  }
-  return result;
-}
-
 static inline float ExecuteF32Min(float a, float b, TrapReason* trap) {
   return JSMin(a, b);
 }
@@ -340,17 +304,6 @@ static inline float ExecuteF32CopySign(float a, float b, TrapReason* trap) {
   return copysignf(a, b);
 }
 
-static inline double ExecuteF64Sub(double a, double b, TrapReason* trap) {
-  double result = a - b;
-  // Some architectures (e.g. MIPS) need extra checking to preserve the payload
-  // of a NaN operand.
-  if (result - result != 0) {
-    if (std::isnan(a)) return quiet(a);
-    if (std::isnan(b)) return quiet(b);
-  }
-  return result;
-}
-
 static inline double ExecuteF64Min(double a, double b, TrapReason* trap) {
   return JSMin(a, b);
 }
@@ -651,19 +604,20 @@ static inline double ExecuteF64ReinterpretI64(int64_t a, TrapReason* trap) {
   return bit_cast<double>(a);
 }
 
-static inline int32_t ExecuteI32ReinterpretF32(float a, TrapReason* trap) {
-  return bit_cast<int32_t>(a);
+static inline int32_t ExecuteI32ReinterpretF32(WasmVal a) {
+  return a.to_unchecked<int32_t>();
 }
 
-static inline int64_t ExecuteI64ReinterpretF64(double a, TrapReason* trap) {
-  return bit_cast<int64_t>(a);
+static inline int64_t ExecuteI64ReinterpretF64(WasmVal a) {
+  return a.to_unchecked<int64_t>();
 }
 
 static inline int32_t ExecuteGrowMemory(uint32_t delta_pages,
                                         WasmInstance* instance) {
   // TODO(ahaas): Move memory allocation to wasm-module.cc for better
   // encapsulation.
-  if (delta_pages > wasm::WasmModule::kV8MaxPages) {
+  if (delta_pages > wasm::kV8MaxWasmMemoryPages ||
+      delta_pages > instance->module->max_mem_pages) {
     return -1;
   }
   uint32_t old_size = instance->mem_size;
@@ -679,8 +633,9 @@ static inline int32_t ExecuteGrowMemory(uint32_t delta_pages,
   } else {
     DCHECK_NOT_NULL(instance->mem_start);
     new_size = old_size + delta_pages * wasm::WasmModule::kPageSize;
-    if (new_size >
-        wasm::WasmModule::kV8MaxPages * wasm::WasmModule::kPageSize) {
+    if (new_size / wasm::WasmModule::kPageSize > wasm::kV8MaxWasmMemoryPages ||
+        new_size / wasm::WasmModule::kPageSize >
+            instance->module->max_mem_pages) {
       return -1;
     }
     new_mem_start = static_cast<byte*>(realloc(instance->mem_start, new_size));
@@ -721,8 +676,8 @@ class ControlTransfers : public ZoneObject {
  public:
   ControlTransferMap map_;
 
-  ControlTransfers(Zone* zone, ModuleEnv* env, AstLocalDecls* locals,
-                   const byte* start, const byte* end)
+  ControlTransfers(Zone* zone, BodyLocalDecls* locals, const byte* start,
+                   const byte* end)
       : map_(zone) {
     // Represents a control flow label.
     struct CLabel : public ZoneObject {
@@ -872,7 +827,7 @@ class ControlTransfers : public ZoneObject {
 // Code and metadata needed to execute a function.
 struct InterpreterCode {
   const WasmFunction* function;  // wasm function
-  AstLocalDecls locals;          // local declarations
+  BodyLocalDecls locals;         // local declarations
   const byte* orig_start;        // start of original code
   const byte* orig_end;          // end of original code
   byte* start;                   // start of (maybe altered) code
@@ -890,14 +845,13 @@ class CodeMap {
   const WasmModule* module_;
   ZoneVector<InterpreterCode> interpreter_code_;
 
-  CodeMap(const WasmModule* module, Zone* zone)
+  CodeMap(const WasmModule* module, const uint8_t* module_start, Zone* zone)
       : zone_(zone), module_(module), interpreter_code_(zone) {
     if (module == nullptr) return;
     for (size_t i = 0; i < module->functions.size(); ++i) {
       const WasmFunction* function = &module->functions[i];
-      const byte* code_start =
-          module->module_start + function->code_start_offset;
-      const byte* code_end = module->module_start + function->code_end_offset;
+      const byte* code_start = module_start + function->code_start_offset;
+      const byte* code_end = module_start + function->code_end_offset;
       AddFunction(function, code_start, code_end);
     }
   }
@@ -929,10 +883,9 @@ class CodeMap {
   InterpreterCode* Preprocess(InterpreterCode* code) {
     if (code->targets == nullptr && code->start) {
       // Compute the control targets map and the local declarations.
-      CHECK(DecodeLocalDecls(code->locals, code->start, code->end));
-      ModuleEnv env = {module_, nullptr, kWasmOrigin};
+      CHECK(DecodeLocalDecls(&code->locals, code->start, code->end));
       code->targets = new (zone_) ControlTransfers(
-          zone_, &env, &code->locals, code->orig_start, code->orig_end);
+          zone_, &code->locals, code->orig_start, code->orig_end);
     }
     return code;
   }
@@ -940,7 +893,7 @@ class CodeMap {
   int AddFunction(const WasmFunction* function, const byte* code_start,
                   const byte* code_end) {
     InterpreterCode code = {
-        function, AstLocalDecls(zone_),          code_start,
+        function, BodyLocalDecls(zone_),         code_start,
         code_end, const_cast<byte*>(code_start), const_cast<byte*>(code_end),
         nullptr};
 
@@ -1072,7 +1025,7 @@ class ThreadImpl : public WasmInterpreter::Thread {
     // Limit of parameters.
     sp_t plimit() { return sp + code->function->sig->parameter_count(); }
     // Limit of locals.
-    sp_t llimit() { return plimit() + code->locals.total_local_count; }
+    sp_t llimit() { return plimit() + code->locals.type_list.size(); }
   };
 
   struct Block {
@@ -1121,28 +1074,28 @@ class ThreadImpl : public WasmInterpreter::Thread {
   }
 
   pc_t InitLocals(InterpreterCode* code) {
-    for (auto p : code->locals.local_types) {
+    for (auto p : code->locals.type_list) {
       WasmVal val;
-      switch (p.first) {
-        case kAstI32:
+      switch (p) {
+        case kWasmI32:
           val = WasmVal(static_cast<int32_t>(0));
           break;
-        case kAstI64:
+        case kWasmI64:
           val = WasmVal(static_cast<int64_t>(0));
           break;
-        case kAstF32:
+        case kWasmF32:
           val = WasmVal(static_cast<float>(0));
           break;
-        case kAstF64:
+        case kWasmF64:
           val = WasmVal(static_cast<double>(0));
           break;
         default:
           UNREACHABLE();
           break;
       }
-      stack_.insert(stack_.end(), p.second, val);
+      stack_.push_back(val);
     }
-    return code->locals.decls_encoded_size;
+    return code->locals.encoded_size;
   }
 
   void CommitPc(pc_t pc) {
@@ -1173,7 +1126,7 @@ class ThreadImpl : public WasmInterpreter::Thread {
   }
 
   bool DoReturn(InterpreterCode** code, pc_t* pc, pc_t* limit, size_t arity) {
-    DCHECK_GT(frames_.size(), 0u);
+    DCHECK_GT(frames_.size(), 0);
     // Pop all blocks for this frame.
     while (!blocks_.empty() && blocks_.back().fp == frames_.size()) {
       blocks_.pop_back();
@@ -1357,12 +1310,6 @@ class ThreadImpl : public WasmInterpreter::Thread {
           blocks_.pop_back();
           break;
         }
-        case kExprI8Const: {
-          ImmI8Operand operand(&decoder, code->at(pc));
-          Push(pc, WasmVal(operand.value));
-          len = 1 + operand.length;
-          break;
-        }
         case kExprI32Const: {
           ImmI32Operand operand(&decoder, code->at(pc));
           Push(pc, WasmVal(operand.value));
@@ -1450,15 +1397,15 @@ class ThreadImpl : public WasmInterpreter::Thread {
           GlobalIndexOperand operand(&decoder, code->at(pc));
           const WasmGlobal* global = &module()->globals[operand.index];
           byte* ptr = instance()->globals_start + global->offset;
-          LocalType type = global->type;
+          ValueType type = global->type;
           WasmVal val;
-          if (type == kAstI32) {
+          if (type == kWasmI32) {
             val = WasmVal(*reinterpret_cast<int32_t*>(ptr));
-          } else if (type == kAstI64) {
+          } else if (type == kWasmI64) {
             val = WasmVal(*reinterpret_cast<int64_t*>(ptr));
-          } else if (type == kAstF32) {
+          } else if (type == kWasmF32) {
             val = WasmVal(*reinterpret_cast<float*>(ptr));
-          } else if (type == kAstF64) {
+          } else if (type == kWasmF64) {
             val = WasmVal(*reinterpret_cast<double*>(ptr));
           } else {
             UNREACHABLE();
@@ -1471,15 +1418,15 @@ class ThreadImpl : public WasmInterpreter::Thread {
           GlobalIndexOperand operand(&decoder, code->at(pc));
           const WasmGlobal* global = &module()->globals[operand.index];
           byte* ptr = instance()->globals_start + global->offset;
-          LocalType type = global->type;
+          ValueType type = global->type;
           WasmVal val = Pop();
-          if (type == kAstI32) {
+          if (type == kWasmI32) {
             *reinterpret_cast<int32_t*>(ptr) = val.to<int32_t>();
-          } else if (type == kAstI64) {
+          } else if (type == kWasmI64) {
             *reinterpret_cast<int64_t*>(ptr) = val.to<int64_t>();
-          } else if (type == kAstF32) {
+          } else if (type == kWasmF32) {
             *reinterpret_cast<float*>(ptr) = val.to<float>();
-          } else if (type == kAstF64) {
+          } else if (type == kWasmF64) {
             *reinterpret_cast<double*>(ptr) = val.to<double>();
           } else {
             UNREACHABLE();
@@ -1605,6 +1552,19 @@ class ThreadImpl : public WasmInterpreter::Thread {
           len = 1 + operand.length;
           break;
         }
+        // We need to treat kExprI32ReinterpretF32 and kExprI64ReinterpretF64
+        // specially to guarantee that the quiet bit of a NaN is preserved on
+        // ia32 by the reinterpret casts.
+        case kExprI32ReinterpretF32: {
+          WasmVal result(ExecuteI32ReinterpretF32(Pop()));
+          Push(pc, result);
+          break;
+        }
+        case kExprI64ReinterpretF64: {
+          WasmVal result(ExecuteI64ReinterpretF64(Pop()));
+          Push(pc, result);
+          break;
+        }
 #define EXECUTE_SIMPLE_BINOP(name, ctype, op)             \
   case kExpr##name: {                                     \
     WasmVal rval = Pop();                                 \
@@ -1680,8 +1640,8 @@ class ThreadImpl : public WasmInterpreter::Thread {
   }
 
   WasmVal Pop() {
-    DCHECK_GT(stack_.size(), 0u);
-    DCHECK_GT(frames_.size(), 0u);
+    DCHECK_GT(stack_.size(), 0);
+    DCHECK_GT(frames_.size(), 0);
     DCHECK_GT(stack_.size(), frames_.back().llimit());  // can't pop into locals
     WasmVal val = stack_.back();
     stack_.pop_back();
@@ -1689,8 +1649,8 @@ class ThreadImpl : public WasmInterpreter::Thread {
   }
 
   void PopN(int n) {
-    DCHECK_GE(stack_.size(), static_cast<size_t>(n));
-    DCHECK_GT(frames_.size(), 0u);
+    DCHECK_GE(stack_.size(), n);
+    DCHECK_GT(frames_.size(), 0);
     size_t nsize = stack_.size() - n;
     DCHECK_GE(nsize, frames_.back().llimit());  // can't pop into locals
     stack_.resize(nsize);
@@ -1698,13 +1658,13 @@ class ThreadImpl : public WasmInterpreter::Thread {
 
   WasmVal PopArity(size_t arity) {
     if (arity == 0) return WasmVal();
-    CHECK_EQ(1u, arity);
+    CHECK_EQ(1, arity);
     return Pop();
   }
 
   void Push(pc_t pc, WasmVal val) {
     // TODO(titzer): store PC as well?
-    if (val.type != kAstStmt) stack_.push_back(val);
+    if (val.type != kWasmStmt) stack_.push_back(val);
   }
 
   void TraceStack(const char* phase, pc_t pc) {
@@ -1730,19 +1690,19 @@ class ThreadImpl : public WasmInterpreter::Thread {
           PrintF(" s%zu:", i);
         WasmVal val = stack_[i];
         switch (val.type) {
-          case kAstI32:
+          case kWasmI32:
             PrintF("i32:%d", val.to<int32_t>());
             break;
-          case kAstI64:
+          case kWasmI64:
             PrintF("i64:%" PRId64 "", val.to<int64_t>());
             break;
-          case kAstF32:
+          case kWasmF32:
             PrintF("f32:%f", val.to<float>());
             break;
-          case kAstF64:
+          case kWasmF64:
             PrintF("f64:%lf", val.to<double>());
             break;
-          case kAstStmt:
+          case kWasmStmt:
             PrintF("void");
             break;
           default:
@@ -1760,14 +1720,19 @@ class ThreadImpl : public WasmInterpreter::Thread {
 class WasmInterpreterInternals : public ZoneObject {
  public:
   WasmInstance* instance_;
+  // Create a copy of the module bytes for the interpreter, since the passed
+  // pointer might be invalidated after constructing the interpreter.
+  const ZoneVector<uint8_t> module_bytes_;
   CodeMap codemap_;
   ZoneVector<ThreadImpl*> threads_;
 
-  WasmInterpreterInternals(Zone* zone, WasmInstance* instance)
-      : instance_(instance),
-        codemap_(instance_ ? instance_->module : nullptr, zone),
+  WasmInterpreterInternals(Zone* zone, const ModuleBytesEnv& env)
+      : instance_(env.instance),
+        module_bytes_(env.module_bytes.start(), env.module_bytes.end(), zone),
+        codemap_(env.instance ? env.instance->module : nullptr,
+                 module_bytes_.data(), zone),
         threads_(zone) {
-    threads_.push_back(new ThreadImpl(zone, &codemap_, instance));
+    threads_.push_back(new ThreadImpl(zone, &codemap_, env.instance));
   }
 
   void Delete() {
@@ -1780,10 +1745,10 @@ class WasmInterpreterInternals : public ZoneObject {
 //============================================================================
 // Implementation of the public interface of the interpreter.
 //============================================================================
-WasmInterpreter::WasmInterpreter(WasmInstance* instance,
+WasmInterpreter::WasmInterpreter(const ModuleBytesEnv& env,
                                  AccountingAllocator* allocator)
     : zone_(allocator, ZONE_NAME),
-      internals_(new (&zone_) WasmInterpreterInternals(&zone_, instance)) {}
+      internals_(new (&zone_) WasmInterpreterInternals(&zone_, env)) {}
 
 WasmInterpreter::~WasmInterpreter() { internals_->Delete(); }
 
@@ -1797,7 +1762,7 @@ bool WasmInterpreter::SetBreakpoint(const WasmFunction* function, pc_t pc,
   if (!code) return false;
   size_t size = static_cast<size_t>(code->end - code->start);
   // Check bounds for {pc}.
-  if (pc < code->locals.decls_encoded_size || pc >= size) return false;
+  if (pc < code->locals.encoded_size || pc >= size) return false;
   // Make a copy of the code before enabling a breakpoint.
   if (enabled && code->orig_start == code->start) {
     code->start = reinterpret_cast<byte*>(zone_.New(size));
@@ -1818,7 +1783,7 @@ bool WasmInterpreter::GetBreakpoint(const WasmFunction* function, pc_t pc) {
   if (!code) return false;
   size_t size = static_cast<size_t>(code->end - code->start);
   // Check bounds for {pc}.
-  if (pc < code->locals.decls_encoded_size || pc >= size) return false;
+  if (pc < code->locals.encoded_size || pc >= size) return false;
   // Check if a breakpoint is present at that place in the code.
   return code->start[pc] == kInternalBreakpoint;
 }
@@ -1841,14 +1806,14 @@ WasmVal WasmInterpreter::GetLocalVal(const WasmFrame* frame, int index) {
   CHECK_GE(index, 0);
   UNIMPLEMENTED();
   WasmVal none;
-  none.type = kAstStmt;
+  none.type = kWasmStmt;
   return none;
 }
 
 WasmVal WasmInterpreter::GetExprVal(const WasmFrame* frame, int pc) {
   UNIMPLEMENTED();
   WasmVal none;
-  none.type = kAstStmt;
+  none.type = kWasmStmt;
   return none;
 }
 
@@ -1885,7 +1850,7 @@ bool WasmInterpreter::SetFunctionCodeForTesting(const WasmFunction* function,
 
 ControlTransferMap WasmInterpreter::ComputeControlTransfersForTesting(
     Zone* zone, const byte* start, const byte* end) {
-  ControlTransfers targets(zone, nullptr, nullptr, start, end);
+  ControlTransfers targets(zone, nullptr, start, end);
   return targets.map_;
 }
 
diff --git a/deps/v8/src/wasm/wasm-interpreter.h b/deps/v8/src/wasm/wasm-interpreter.h
index 360362b994..80e6c4ba79 100644
--- a/deps/v8/src/wasm/wasm-interpreter.h
+++ b/deps/v8/src/wasm/wasm-interpreter.h
@@ -17,8 +17,8 @@ namespace internal {
 namespace wasm {
 
 // forward declarations.
+struct ModuleBytesEnv;
 struct WasmFunction;
-struct WasmInstance;
 class WasmInterpreterInternals;
 
 typedef size_t pc_t;
@@ -32,23 +32,23 @@ typedef ZoneMap<pc_t, pcdiff_t> ControlTransferMap;
 
 // Macro for defining union members.
 #define FOREACH_UNION_MEMBER(V) \
-  V(i32, kAstI32, int32_t)      \
-  V(u32, kAstI32, uint32_t)     \
-  V(i64, kAstI64, int64_t)      \
-  V(u64, kAstI64, uint64_t)     \
-  V(f32, kAstF32, float)        \
-  V(f64, kAstF64, double)
+  V(i32, kWasmI32, int32_t)     \
+  V(u32, kWasmI32, uint32_t)    \
+  V(i64, kWasmI64, int64_t)     \
+  V(u64, kWasmI64, uint64_t)    \
+  V(f32, kWasmF32, float)       \
+  V(f64, kWasmF64, double)
 
 // Representation of values within the interpreter.
 struct WasmVal {
-  LocalType type;
+  ValueType type;
   union {
 #define DECLARE_FIELD(field, localtype, ctype) ctype field;
     FOREACH_UNION_MEMBER(DECLARE_FIELD)
 #undef DECLARE_FIELD
   } val;
 
-  WasmVal() : type(kAstStmt) {}
+  WasmVal() : type(kWasmStmt) {}
 
 #define DECLARE_CONSTRUCTOR(field, localtype, ctype) \
   explicit WasmVal(ctype v) : type(localtype) { val.field = v; }
@@ -56,13 +56,22 @@ struct WasmVal {
 #undef DECLARE_CONSTRUCTOR
 
   template <typename T>
-  T to() {
+  inline T to() {
+    UNREACHABLE();
+  }
+
+  template <typename T>
+  inline T to_unchecked() {
     UNREACHABLE();
   }
 };
 
 #define DECLARE_CAST(field, localtype, ctype) \
   template <>                                 \
+  inline ctype WasmVal::to_unchecked() {      \
+    return val.field;                         \
+  }                                           \
+  template <>                                 \
   inline ctype WasmVal::to() {                \
     CHECK_EQ(localtype, type);                \
     return val.field;                         \
@@ -70,11 +79,6 @@ struct WasmVal {
 FOREACH_UNION_MEMBER(DECLARE_CAST)
 #undef DECLARE_CAST
 
-template <>
-inline void WasmVal::to() {
-  CHECK_EQ(kAstStmt, type);
-}
-
 // Representation of frames within the interpreter.
 class WasmFrame {
  public:
@@ -135,7 +139,7 @@ class V8_EXPORT_PRIVATE WasmInterpreter {
     bool GetBreakpoint(const WasmFunction* function, int pc);
   };
 
-  WasmInterpreter(WasmInstance* instance, AccountingAllocator* allocator);
+  WasmInterpreter(const ModuleBytesEnv& env, AccountingAllocator* allocator);
   ~WasmInterpreter();
 
   //==========================================================================
diff --git a/deps/v8/src/wasm/wasm-js.cc b/deps/v8/src/wasm/wasm-js.cc
index 0e030a28c4..b426d5bf3d 100644
--- a/deps/v8/src/wasm/wasm-js.cc
+++ b/deps/v8/src/wasm/wasm-js.cc
@@ -18,6 +18,7 @@
 
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-js.h"
+#include "src/wasm/wasm-limits.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-objects.h"
 #include "src/wasm/wasm-result.h"
@@ -28,13 +29,12 @@ using v8::internal::wasm::ErrorThrower;
 
 namespace v8 {
 
-enum WasmMemoryObjectData {
-  kWasmMemoryBuffer,
-  kWasmMemoryMaximum,
-  kWasmMemoryInstanceObject
-};
-
 namespace {
+
+#define RANGE_ERROR_MSG                                                        \
+  "Wasm compilation exceeds internal limits in this context for the provided " \
+  "arguments"
+
 i::Handle<i::String> v8_str(i::Isolate* isolate, const char* str) {
   return isolate->factory()->NewStringFromAsciiChecked(str);
 }
@@ -48,6 +48,100 @@ struct RawBuffer {
   size_t size() { return static_cast<size_t>(end - start); }
 };
 
+bool IsCompilationAllowed(i::Isolate* isolate, ErrorThrower* thrower,
+                          v8::Local<v8::Value> source, bool is_async) {
+  // Allow caller to do one final check on thrower state, rather than
+  // one at each step. No information is lost - failure reason is captured
+  // in the thrower state.
+  if (thrower->error()) return false;
+
+  AllowWasmCompileCallback callback = isolate->allow_wasm_compile_callback();
+  if (callback != nullptr &&
+      !callback(reinterpret_cast<v8::Isolate*>(isolate), source, is_async)) {
+    thrower->RangeError(RANGE_ERROR_MSG);
+    return false;
+  }
+  return true;
+}
+
+bool IsInstantiationAllowed(i::Isolate* isolate, ErrorThrower* thrower,
+                            v8::Local<v8::Value> module_or_bytes,
+                            i::MaybeHandle<i::JSReceiver> ffi, bool is_async) {
+  // Allow caller to do one final check on thrower state, rather than
+  // one at each step. No information is lost - failure reason is captured
+  // in the thrower state.
+  if (thrower->error()) return false;
+  v8::MaybeLocal<v8::Value> v8_ffi;
+  if (!ffi.is_null()) {
+    v8_ffi = v8::Local<v8::Value>::Cast(Utils::ToLocal(ffi.ToHandleChecked()));
+  }
+  AllowWasmInstantiateCallback callback =
+      isolate->allow_wasm_instantiate_callback();
+  if (callback != nullptr &&
+      !callback(reinterpret_cast<v8::Isolate*>(isolate), module_or_bytes,
+                v8_ffi, is_async)) {
+    thrower->RangeError(RANGE_ERROR_MSG);
+    return false;
+  }
+  return true;
+}
+
+i::wasm::ModuleWireBytes GetFirstArgumentAsBytes(
+    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower) {
+  if (args.Length() < 1) {
+    thrower->TypeError("Argument 0 must be a buffer source");
+    return i::wasm::ModuleWireBytes(nullptr, nullptr);
+  }
+
+  const byte* start = nullptr;
+  size_t length = 0;
+  v8::Local<v8::Value> source = args[0];
+  if (source->IsArrayBuffer()) {
+    // A raw array buffer was passed.
+    Local<ArrayBuffer> buffer = Local<ArrayBuffer>::Cast(source);
+    ArrayBuffer::Contents contents = buffer->GetContents();
+
+    start = reinterpret_cast<const byte*>(contents.Data());
+    length = contents.ByteLength();
+  } else if (source->IsTypedArray()) {
+    // A TypedArray was passed.
+    Local<TypedArray> array = Local<TypedArray>::Cast(source);
+    Local<ArrayBuffer> buffer = array->Buffer();
+
+    ArrayBuffer::Contents contents = buffer->GetContents();
+
+    start =
+        reinterpret_cast<const byte*>(contents.Data()) + array->ByteOffset();
+    length = array->ByteLength();
+  } else {
+    thrower->TypeError("Argument 0 must be a buffer source");
+  }
+  DCHECK_IMPLIES(length, start != nullptr);
+  if (length == 0) {
+    thrower->CompileError("BufferSource argument is empty");
+  }
+  if (length > i::wasm::kV8MaxWasmModuleSize) {
+    thrower->RangeError("buffer source exceeds maximum size of %zu (is %zu)",
+                        i::wasm::kV8MaxWasmModuleSize, length);
+  }
+  if (thrower->error()) return i::wasm::ModuleWireBytes(nullptr, nullptr);
+  // TODO(titzer): use the handle as well?
+  return i::wasm::ModuleWireBytes(start, start + length);
+}
+
+i::MaybeHandle<i::JSReceiver> GetSecondArgumentAsImports(
+    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower) {
+  if (args.Length() < 2) return {};
+  if (args[1]->IsUndefined()) return {};
+
+  if (!args[1]->IsObject()) {
+    thrower->TypeError("Argument 1 must be an object");
+    return {};
+  }
+  Local<Object> obj = Local<Object>::Cast(args[1]);
+  return i::Handle<i::JSReceiver>::cast(v8::Utils::OpenHandle(*obj));
+}
+
 RawBuffer GetRawBufferSource(
     v8::Local<v8::Value> source, ErrorThrower* thrower) {
   const byte* start = nullptr;
@@ -61,9 +155,6 @@ RawBuffer GetRawBufferSource(
     start = reinterpret_cast<const byte*>(contents.Data());
     end = start + contents.ByteLength();
 
-    if (start == nullptr || end == start) {
-      thrower->CompileError("ArrayBuffer argument is empty");
-    }
   } else if (source->IsTypedArray()) {
     // A TypedArray was passed.
     Local<TypedArray> array = Local<TypedArray>::Cast(source);
@@ -75,13 +166,12 @@ RawBuffer GetRawBufferSource(
         reinterpret_cast<const byte*>(contents.Data()) + array->ByteOffset();
     end = start + array->ByteLength();
 
-    if (start == nullptr || end == start) {
-      thrower->TypeError("ArrayBuffer argument is empty");
-    }
   } else {
-    thrower->TypeError("Argument 0 must be an ArrayBuffer or Uint8Array");
+    thrower->TypeError("Argument 0 must be a buffer source");
+  }
+  if (start == nullptr || end == start) {
+    thrower->CompileError("BufferSource argument is empty");
   }
-
   return {start, end};
 }
 
@@ -97,7 +187,7 @@ static i::MaybeHandle<i::WasmModuleObject> CreateModuleObject(
   DCHECK(source->IsArrayBuffer() || source->IsTypedArray());
   return i::wasm::CreateModuleObjectFromBytes(
       i_isolate, buffer.start, buffer.end, thrower, i::wasm::kWasmOrigin,
-      i::Handle<i::Script>::null(), nullptr, nullptr);
+      i::Handle<i::Script>::null(), i::Vector<const byte>::empty());
 }
 
 static bool ValidateModule(v8::Isolate* isolate,
@@ -115,6 +205,17 @@ static bool ValidateModule(v8::Isolate* isolate,
                                       i::wasm::ModuleOrigin::kWasmOrigin);
 }
 
+// TODO(wasm): move brand check to the respective types, and don't throw
+// in it, rather, use a provided ErrorThrower, or let caller handle it.
+static bool BrandCheck(Isolate* isolate, i::Handle<i::Object> value,
+                       i::Handle<i::Symbol> sym) {
+  if (!value->IsJSObject()) return false;
+  i::Handle<i::JSObject> object = i::Handle<i::JSObject>::cast(value);
+  Maybe<bool> has_brand = i::JSObject::HasOwnProperty(object, sym);
+  if (has_brand.IsNothing()) return false;
+  return has_brand.ToChecked();
+}
+
 static bool BrandCheck(Isolate* isolate, i::Handle<i::Object> value,
                        i::Handle<i::Symbol> sym, const char* msg) {
   if (value->IsJSObject()) {
@@ -130,27 +231,36 @@ static bool BrandCheck(Isolate* isolate, i::Handle<i::Object> value,
 
 void WebAssemblyCompile(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
                        "WebAssembly.compile()");
 
+  Local<Context> context = isolate->GetCurrentContext();
+  v8::Local<v8::Promise::Resolver> resolver;
+  if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(resolver->GetPromise());
+
   if (args.Length() < 1) {
     thrower.TypeError("Argument 0 must be a buffer source");
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+    return;
+  }
+  auto bytes = GetFirstArgumentAsBytes(args, &thrower);
+  USE(bytes);
+  if (!IsCompilationAllowed(i_isolate, &thrower, args[0], true)) {
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
     return;
   }
   i::MaybeHandle<i::JSObject> module_obj =
       CreateModuleObject(isolate, args[0], &thrower);
 
-  Local<Context> context = isolate->GetCurrentContext();
-  v8::Local<v8::Promise::Resolver> resolver;
-  if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
   if (thrower.error()) {
     resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
   } else {
     resolver->Resolve(context, Utils::ToLocal(module_obj.ToHandleChecked()));
   }
-  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
-  return_value.Set(resolver->GetPromise());
 }
 
 void WebAssemblyValidate(const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ -168,12 +278,14 @@ void WebAssemblyValidate(const v8::FunctionCallbackInfo<v8::Value>& args) {
   if (ValidateModule(isolate, args[0], &thrower)) {
     return_value.Set(v8::True(isolate));
   } else {
+    if (thrower.wasm_error()) thrower.Reify();  // Clear error.
     return_value.Set(v8::False(isolate));
   }
 }
 
 void WebAssemblyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
                        "WebAssembly.Module()");
@@ -182,6 +294,10 @@ void WebAssemblyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
     thrower.TypeError("Argument 0 must be a buffer source");
     return;
   }
+  auto bytes = GetFirstArgumentAsBytes(args, &thrower);
+  USE(bytes);
+  if (!IsCompilationAllowed(i_isolate, &thrower, args[0], false)) return;
+
   i::MaybeHandle<i::JSObject> module_obj =
       CreateModuleObject(isolate, args[0], &thrower);
   if (module_obj.is_null()) return;
@@ -190,16 +306,49 @@ void WebAssemblyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   return_value.Set(Utils::ToLocal(module_obj.ToHandleChecked()));
 }
 
-void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
-  HandleScope scope(args.GetIsolate());
-  v8::Isolate* isolate = args.GetIsolate();
-  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+MaybeLocal<Value> InstantiateModuleImpl(
+    i::Isolate* i_isolate, i::Handle<i::WasmModuleObject> i_module_obj,
+    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower* thrower) {
+  // It so happens that in both the WebAssembly.instantiate, as well as
+  // WebAssembly.Instance ctor, the positions of the ffi object and memory
+  // are the same. If that changes later, we refactor the consts into
+  // parameters.
+  static const int kFfiOffset = 1;
 
-  ErrorThrower thrower(i_isolate, "WebAssembly.Instance()");
+  MaybeLocal<Value> nothing;
+  i::Handle<i::JSReceiver> ffi = i::Handle<i::JSObject>::null();
+  // This is a first - level validation of the argument. If present, we only
+  // check its type. {Instantiate} will further check that if the module
+  // has imports, the argument must be present, as well as piecemeal
+  // import satisfaction.
+  if (args.Length() > kFfiOffset && !args[kFfiOffset]->IsUndefined()) {
+    if (!args[kFfiOffset]->IsObject()) {
+      thrower->TypeError("Argument %d must be an object", kFfiOffset);
+      return nothing;
+    }
+    Local<Object> obj = Local<Object>::Cast(args[kFfiOffset]);
+    ffi = i::Handle<i::JSReceiver>::cast(v8::Utils::OpenHandle(*obj));
+  }
+
+  i::MaybeHandle<i::JSObject> instance =
+      i::wasm::WasmModule::Instantiate(i_isolate, thrower, i_module_obj, ffi);
+  if (instance.is_null()) {
+    if (!thrower->error())
+      thrower->RuntimeError("Could not instantiate module");
+    return nothing;
+  }
+  DCHECK(!i_isolate->has_pending_exception());
+  return Utils::ToLocal(instance.ToHandleChecked());
+}
 
+namespace {
+i::MaybeHandle<i::WasmModuleObject> GetFirstArgumentAsModule(
+    const v8::FunctionCallbackInfo<v8::Value>& args, ErrorThrower& thrower) {
+  v8::Isolate* isolate = args.GetIsolate();
+  i::MaybeHandle<i::WasmModuleObject> nothing;
   if (args.Length() < 1) {
     thrower.TypeError("Argument 0 must be a WebAssembly.Module");
-    return;
+    return nothing;
   }
 
   Local<Context> context = isolate->GetCurrentContext();
@@ -207,60 +356,210 @@ void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
   if (!BrandCheck(isolate, Utils::OpenHandle(*args[0]),
                   i::Handle<i::Symbol>(i_context->wasm_module_sym()),
                   "Argument 0 must be a WebAssembly.Module")) {
-    return;
+    return nothing;
   }
 
-  Local<Object> obj = Local<Object>::Cast(args[0]);
-  i::Handle<i::JSObject> i_obj =
-      i::Handle<i::JSObject>::cast(v8::Utils::OpenHandle(*obj));
+  Local<Object> module_obj = Local<Object>::Cast(args[0]);
+  return i::Handle<i::WasmModuleObject>::cast(
+      v8::Utils::OpenHandle(*module_obj));
+}
+}  // namespace
 
-  i::Handle<i::JSReceiver> ffi = i::Handle<i::JSObject>::null();
-  if (args.Length() > 1 && args[1]->IsObject()) {
-    Local<Object> obj = Local<Object>::Cast(args[1]);
-    ffi = i::Handle<i::JSReceiver>::cast(v8::Utils::OpenHandle(*obj));
+void WebAssemblyModuleImports(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  ErrorThrower thrower(i_isolate, "WebAssembly.Module.imports()");
+
+  auto maybe_module = GetFirstArgumentAsModule(args, thrower);
+
+  if (!maybe_module.is_null()) {
+    auto imports =
+        i::wasm::GetImports(i_isolate, maybe_module.ToHandleChecked());
+    args.GetReturnValue().Set(Utils::ToLocal(imports));
   }
+}
 
-  i::Handle<i::JSArrayBuffer> memory = i::Handle<i::JSArrayBuffer>::null();
-  if (args.Length() > 2 && args[2]->IsObject()) {
-    Local<Object> obj = Local<Object>::Cast(args[2]);
-    i::Handle<i::Object> mem_obj = v8::Utils::OpenHandle(*obj);
-    if (i::WasmJs::IsWasmMemoryObject(i_isolate, mem_obj)) {
-      memory = i::Handle<i::JSArrayBuffer>(
-          i::Handle<i::WasmMemoryObject>::cast(mem_obj)->get_buffer(),
-          i_isolate);
-    } else {
-      thrower.TypeError("Argument 2 must be a WebAssembly.Memory");
+void WebAssemblyModuleExports(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+
+  ErrorThrower thrower(i_isolate, "WebAssembly.Module.exports()");
+
+  auto maybe_module = GetFirstArgumentAsModule(args, thrower);
+
+  if (!maybe_module.is_null()) {
+    auto exports =
+        i::wasm::GetExports(i_isolate, maybe_module.ToHandleChecked());
+    args.GetReturnValue().Set(Utils::ToLocal(exports));
+  }
+}
+
+void WebAssemblyModuleCustomSections(
+    const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+
+  ErrorThrower thrower(i_isolate, "WebAssembly.Module.customSections()");
+
+  auto maybe_module = GetFirstArgumentAsModule(args, thrower);
+
+  if (args.Length() < 2) {
+    thrower.TypeError("Argument 1 must be a string");
+    return;
+  }
+
+  i::Handle<i::Object> name = Utils::OpenHandle(*args[1]);
+  if (!name->IsString()) {
+    thrower.TypeError("Argument 1 must be a string");
+    return;
+  }
+
+  if (!maybe_module.is_null()) {
+    auto custom_sections =
+        i::wasm::GetCustomSections(i_isolate, maybe_module.ToHandleChecked(),
+                                   i::Handle<i::String>::cast(name), &thrower);
+    if (!thrower.error()) {
+      args.GetReturnValue().Set(Utils::ToLocal(custom_sections));
     }
   }
-  i::MaybeHandle<i::JSObject> instance =
-      i::wasm::WasmModule::Instantiate(i_isolate, &thrower, i_obj, ffi, memory);
-  if (instance.is_null()) {
-    if (!thrower.error()) thrower.RuntimeError("Could not instantiate module");
+}
+
+void WebAssemblyInstance(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  HandleScope scope(args.GetIsolate());
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+
+  ErrorThrower thrower(i_isolate, "WebAssembly.Instance()");
+
+  auto maybe_module = GetFirstArgumentAsModule(args, thrower);
+  if (thrower.error()) return;
+  auto maybe_imports = GetSecondArgumentAsImports(args, &thrower);
+  if (!IsInstantiationAllowed(i_isolate, &thrower, args[0], maybe_imports,
+                              false)) {
     return;
   }
-  DCHECK(!i_isolate->has_pending_exception());
+  DCHECK(!thrower.error());
+
+  if (!maybe_module.is_null()) {
+    MaybeLocal<Value> instance = InstantiateModuleImpl(
+        i_isolate, maybe_module.ToHandleChecked(), args, &thrower);
+    if (instance.IsEmpty()) {
+      DCHECK(thrower.error());
+      return;
+    }
+    args.GetReturnValue().Set(instance.ToLocalChecked());
+  }
+}
+
+void WebAssemblyInstantiate(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  v8::Isolate* isolate = args.GetIsolate();
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+
+  HandleScope scope(isolate);
+  ErrorThrower thrower(i_isolate, "WebAssembly.instantiate()");
+
+  Local<Context> context = isolate->GetCurrentContext();
+  i::Handle<i::Context> i_context = Utils::OpenHandle(*context);
+
+  v8::Local<v8::Promise::Resolver> resolver;
+  if (!v8::Promise::Resolver::New(context).ToLocal(&resolver)) return;
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
-  return_value.Set(Utils::ToLocal(instance.ToHandleChecked()));
+  return_value.Set(resolver->GetPromise());
+
+  if (args.Length() < 1) {
+    thrower.TypeError(
+        "Argument 0 must be provided and must be either a buffer source or a "
+        "WebAssembly.Module object");
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+    return;
+  }
+
+  i::Handle<i::Object> first_arg = Utils::OpenHandle(*args[0]);
+  if (!first_arg->IsJSObject()) {
+    thrower.TypeError(
+        "Argument 0 must be a buffer source or a WebAssembly.Module object");
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+    return;
+  }
+
+  bool want_pair = !BrandCheck(
+      isolate, first_arg, i::Handle<i::Symbol>(i_context->wasm_module_sym()));
+  auto maybe_imports = GetSecondArgumentAsImports(args, &thrower);
+  if (thrower.error()) {
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+    return;
+  }
+  if (!IsInstantiationAllowed(i_isolate, &thrower, args[0], maybe_imports,
+                              true)) {
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+    return;
+  }
+  i::Handle<i::WasmModuleObject> module_obj;
+  if (want_pair) {
+    i::MaybeHandle<i::WasmModuleObject> maybe_module_obj =
+        CreateModuleObject(isolate, args[0], &thrower);
+    if (!maybe_module_obj.ToHandle(&module_obj)) {
+      DCHECK(thrower.error());
+      resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+      return;
+    }
+  } else {
+    module_obj = i::Handle<i::WasmModuleObject>::cast(first_arg);
+  }
+  DCHECK(!module_obj.is_null());
+  MaybeLocal<Value> instance =
+      InstantiateModuleImpl(i_isolate, module_obj, args, &thrower);
+  if (instance.IsEmpty()) {
+    DCHECK(thrower.error());
+    resolver->Reject(context, Utils::ToLocal(thrower.Reify()));
+  } else {
+    DCHECK(!thrower.error());
+    Local<Value> retval;
+    if (want_pair) {
+      i::Handle<i::JSFunction> object_function = i::Handle<i::JSFunction>(
+          i_isolate->native_context()->object_function(), i_isolate);
+
+      i::Handle<i::JSObject> i_retval =
+          i_isolate->factory()->NewJSObject(object_function, i::TENURED);
+      i::Handle<i::String> module_property_name =
+          i_isolate->factory()->InternalizeUtf8String("module");
+      i::Handle<i::String> instance_property_name =
+          i_isolate->factory()->InternalizeUtf8String("instance");
+      i::JSObject::AddProperty(i_retval, module_property_name, module_obj,
+                               i::NONE);
+      i::JSObject::AddProperty(i_retval, instance_property_name,
+                               Utils::OpenHandle(*instance.ToLocalChecked()),
+                               i::NONE);
+      retval = Utils::ToLocal(i_retval);
+    } else {
+      retval = instance.ToLocalChecked();
+    }
+    DCHECK(!retval.IsEmpty());
+    resolver->Resolve(context, retval);
+  }
 }
 
 bool GetIntegerProperty(v8::Isolate* isolate, ErrorThrower* thrower,
                         Local<Context> context, Local<v8::Object> object,
-                        Local<String> property, int* result, int lower_bound,
-                        int upper_bound) {
+                        Local<String> property, int* result,
+                        int64_t lower_bound, uint64_t upper_bound) {
   v8::MaybeLocal<v8::Value> maybe = object->Get(context, property);
   v8::Local<v8::Value> value;
   if (maybe.ToLocal(&value)) {
     int64_t number;
     if (!value->IntegerValue(context).To(&number)) return false;
-    if (number < static_cast<int64_t>(lower_bound)) {
+    if (number < lower_bound) {
       thrower->RangeError("Property value %" PRId64
-                          " is below the lower bound %d",
+                          " is below the lower bound %" PRIx64,
                           number, lower_bound);
       return false;
     }
     if (number > static_cast<int64_t>(upper_bound)) {
       thrower->RangeError("Property value %" PRId64
-                          " is above the upper bound %d",
+                          " is above the upper bound %" PRIu64,
                           number, upper_bound);
       return false;
     }
@@ -270,8 +569,6 @@ bool GetIntegerProperty(v8::Isolate* isolate, ErrorThrower* thrower,
   return false;
 }
 
-const int max_table_size = 1 << 26;
-
 void WebAssemblyTable(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   HandleScope scope(isolate);
@@ -299,28 +596,23 @@ void WebAssemblyTable(const v8::FunctionCallbackInfo<v8::Value>& args) {
     }
   }
   // The descriptor's 'initial'.
-  int initial;
+  int initial = 0;
   if (!GetIntegerProperty(isolate, &thrower, context, descriptor,
                           v8_str(isolate, "initial"), &initial, 0,
-                          max_table_size)) {
+                          i::wasm::kV8MaxWasmTableSize)) {
     return;
   }
   // The descriptor's 'maximum'.
-  int maximum = 0;
+  int maximum = -1;
   Local<String> maximum_key = v8_str(isolate, "maximum");
   Maybe<bool> has_maximum = descriptor->Has(context, maximum_key);
 
-  if (has_maximum.IsNothing()) {
-    // There has been an exception, just return.
-    return;
-  }
-  if (has_maximum.FromJust()) {
+  if (!has_maximum.IsNothing() && has_maximum.FromJust()) {
     if (!GetIntegerProperty(isolate, &thrower, context, descriptor, maximum_key,
-                            &maximum, initial, max_table_size)) {
+                            &maximum, initial,
+                            i::wasm::kSpecMaxWasmTableSize)) {
       return;
     }
-  } else {
-    maximum = static_cast<int>(i::wasm::WasmModule::kV8MaxTableSize);
   }
 
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
@@ -335,7 +627,7 @@ void WebAssemblyMemory(const v8::FunctionCallbackInfo<v8::Value>& args) {
   v8::Isolate* isolate = args.GetIsolate();
   HandleScope scope(isolate);
   ErrorThrower thrower(reinterpret_cast<i::Isolate*>(isolate),
-                       "WebAssembly.Module()");
+                       "WebAssembly.Memory()");
   if (args.Length() < 1 || !args[0]->IsObject()) {
     thrower.TypeError("Argument 0 must be a memory descriptor");
     return;
@@ -343,35 +635,35 @@ void WebAssemblyMemory(const v8::FunctionCallbackInfo<v8::Value>& args) {
   Local<Context> context = isolate->GetCurrentContext();
   Local<v8::Object> descriptor = args[0]->ToObject(context).ToLocalChecked();
   // The descriptor's 'initial'.
-  int initial;
+  int initial = 0;
   if (!GetIntegerProperty(isolate, &thrower, context, descriptor,
-                          v8_str(isolate, "initial"), &initial, 0, 65536)) {
+                          v8_str(isolate, "initial"), &initial, 0,
+                          i::wasm::kV8MaxWasmMemoryPages)) {
     return;
   }
   // The descriptor's 'maximum'.
-  int maximum = 0;
+  int maximum = -1;
   Local<String> maximum_key = v8_str(isolate, "maximum");
   Maybe<bool> has_maximum = descriptor->Has(context, maximum_key);
 
-  if (has_maximum.IsNothing()) {
-    // There has been an exception, just return.
-    return;
-  }
-  if (has_maximum.FromJust()) {
+  if (!has_maximum.IsNothing() && has_maximum.FromJust()) {
     if (!GetIntegerProperty(isolate, &thrower, context, descriptor, maximum_key,
-                            &maximum, initial, 65536)) {
+                            &maximum, initial,
+                            i::wasm::kSpecMaxWasmMemoryPages)) {
       return;
     }
   }
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::Handle<i::JSArrayBuffer> buffer =
-      i_isolate->factory()->NewJSArrayBuffer(i::SharedFlag::kNotShared);
   size_t size = static_cast<size_t>(i::wasm::WasmModule::kPageSize) *
                 static_cast<size_t>(initial);
-  i::JSArrayBuffer::SetupAllocatingData(buffer, i_isolate, size);
-
-  i::Handle<i::JSObject> memory_obj = i::WasmMemoryObject::New(
-      i_isolate, buffer, has_maximum.FromJust() ? maximum : -1);
+  i::Handle<i::JSArrayBuffer> buffer =
+      i::wasm::NewArrayBuffer(i_isolate, size, i::FLAG_wasm_guard_pages);
+  if (buffer.is_null()) {
+    thrower.RangeError("could not allocate memory");
+    return;
+  }
+  i::Handle<i::JSObject> memory_obj =
+      i::WasmMemoryObject::New(i_isolate, buffer, maximum);
   args.GetReturnValue().Set(Utils::ToLocal(memory_obj));
 }
 
@@ -404,7 +696,7 @@ void WebAssemblyTableGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   auto receiver =
       i::Handle<i::WasmTableObject>::cast(Utils::OpenHandle(*args.This()));
-  i::Handle<i::FixedArray> old_array(receiver->get_functions(), i_isolate);
+  i::Handle<i::FixedArray> old_array(receiver->functions(), i_isolate);
   int old_size = old_array->length();
   int64_t new_size64 = 0;
   if (args.Length() > 0 && !args[0]->IntegerValue(context).To(&new_size64)) {
@@ -412,14 +704,23 @@ void WebAssemblyTableGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
   }
   new_size64 += old_size;
 
-  if (new_size64 < old_size || new_size64 > receiver->maximum_length()) {
+  int64_t max_size64 = receiver->maximum_length();
+  if (max_size64 < 0 ||
+      max_size64 > static_cast<int64_t>(i::wasm::kV8MaxWasmTableSize)) {
+    max_size64 = i::wasm::kV8MaxWasmTableSize;
+  }
+
+  if (new_size64 < old_size || new_size64 > max_size64) {
     v8::Local<v8::Value> e = v8::Exception::RangeError(
         v8_str(isolate, new_size64 < old_size ? "trying to shrink table"
                                               : "maximum table size exceeded"));
     isolate->ThrowException(e);
     return;
   }
+
   int new_size = static_cast<int>(new_size64);
+  i::WasmTableObject::Grow(i_isolate, receiver,
+                           static_cast<uint32_t>(new_size - old_size));
 
   if (new_size != old_size) {
     i::Handle<i::FixedArray> new_array =
@@ -430,7 +731,9 @@ void WebAssemblyTableGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
     receiver->set_functions(*new_array);
   }
 
-  // TODO(titzer): update relevant instances.
+  // TODO(gdeepti): use weak links for instances
+  v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
+  return_value.Set(old_size);
 }
 
 void WebAssemblyTableGet(const v8::FunctionCallbackInfo<v8::Value>& args) {
@@ -446,7 +749,7 @@ void WebAssemblyTableGet(const v8::FunctionCallbackInfo<v8::Value>& args) {
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
   auto receiver =
       i::Handle<i::WasmTableObject>::cast(Utils::OpenHandle(*args.This()));
-  i::Handle<i::FixedArray> array(receiver->get_functions(), i_isolate);
+  i::Handle<i::FixedArray> array(receiver->functions(), i_isolate);
   int i = 0;
   if (args.Length() > 0 && !args[0]->Int32Value(context).To(&i)) return;
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
@@ -490,7 +793,7 @@ void WebAssemblyTableSet(const v8::FunctionCallbackInfo<v8::Value>& args) {
 
   auto receiver =
       i::Handle<i::WasmTableObject>::cast(Utils::OpenHandle(*args.This()));
-  i::Handle<i::FixedArray> array(receiver->get_functions(), i_isolate);
+  i::Handle<i::FixedArray> array(receiver->functions(), i_isolate);
   int i;
   if (!args[0]->Int32Value(context).To(&i)) return;
   if (i < 0 || i >= array->length()) {
@@ -500,7 +803,7 @@ void WebAssemblyTableSet(const v8::FunctionCallbackInfo<v8::Value>& args) {
     return;
   }
 
-  i::Handle<i::FixedArray> dispatch_tables(receiver->get_dispatch_tables(),
+  i::Handle<i::FixedArray> dispatch_tables(receiver->dispatch_tables(),
                                            i_isolate);
   if (value->IsNull(i_isolate)) {
     i::wasm::UpdateDispatchTables(i_isolate, dispatch_tables, i,
@@ -522,40 +825,40 @@ void WebAssemblyMemoryGrow(const v8::FunctionCallbackInfo<v8::Value>& args) {
                   "Receiver is not a WebAssembly.Memory")) {
     return;
   }
-  if (args.Length() < 1) {
+  int64_t delta_size = 0;
+  if (args.Length() < 1 || !args[0]->IntegerValue(context).To(&delta_size)) {
     v8::Local<v8::Value> e = v8::Exception::TypeError(
         v8_str(isolate, "Argument 0 required, must be numeric value of pages"));
     isolate->ThrowException(e);
     return;
   }
-
-  uint32_t delta = args[0]->Uint32Value(context).FromJust();
-  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::Handle<i::JSObject> receiver =
-      i::Handle<i::JSObject>::cast(Utils::OpenHandle(*args.This()));
-  i::Handle<i::Object> instance_object(
-      receiver->GetInternalField(kWasmMemoryInstanceObject), i_isolate);
-  i::Handle<i::JSObject> instance(
-      i::Handle<i::JSObject>::cast(instance_object));
-
-  // TODO(gdeepti) Implement growing memory when shared by different
-  // instances.
-  int32_t ret = internal::wasm::GrowInstanceMemory(i_isolate, instance, delta);
-  if (ret == -1) {
-    v8::Local<v8::Value> e = v8::Exception::Error(
-        v8_str(isolate, "Unable to grow instance memory."));
+  i::Handle<i::WasmMemoryObject> receiver =
+      i::Handle<i::WasmMemoryObject>::cast(Utils::OpenHandle(*args.This()));
+  int64_t max_size64 = receiver->maximum_pages();
+  if (max_size64 < 0 ||
+      max_size64 > static_cast<int64_t>(i::wasm::kV8MaxWasmTableSize)) {
+    max_size64 = i::wasm::kV8MaxWasmMemoryPages;
+  }
+  i::Handle<i::JSArrayBuffer> old_buffer(receiver->buffer());
+  uint32_t old_size =
+      old_buffer->byte_length()->Number() / i::wasm::kSpecMaxWasmMemoryPages;
+  int64_t new_size64 = old_size + delta_size;
+  if (delta_size < 0 || max_size64 < new_size64 || new_size64 < old_size) {
+    v8::Local<v8::Value> e = v8::Exception::RangeError(v8_str(
+        isolate, new_size64 < old_size ? "trying to shrink memory"
+                                       : "maximum memory size exceeded"));
     isolate->ThrowException(e);
     return;
   }
-  i::MaybeHandle<i::JSArrayBuffer> buffer =
-      internal::wasm::GetInstanceMemory(i_isolate, instance);
-  if (buffer.is_null()) {
-    v8::Local<v8::Value> e = v8::Exception::Error(
-        v8_str(isolate, "WebAssembly.Memory buffer object not set."));
+  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
+  int32_t ret = i::wasm::GrowWebAssemblyMemory(
+      i_isolate, receiver, static_cast<uint32_t>(delta_size));
+  if (ret == -1) {
+    v8::Local<v8::Value> e = v8::Exception::RangeError(
+        v8_str(isolate, "Unable to grow instance memory."));
     isolate->ThrowException(e);
     return;
   }
-  receiver->SetInternalField(kWasmMemoryBuffer, *buffer.ToHandleChecked());
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(ret);
 }
@@ -571,10 +874,9 @@ void WebAssemblyMemoryGetBuffer(
     return;
   }
   i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::Handle<i::JSObject> receiver =
-      i::Handle<i::JSObject>::cast(Utils::OpenHandle(*args.This()));
-  i::Handle<i::Object> buffer(receiver->GetInternalField(kWasmMemoryBuffer),
-                              i_isolate);
+  i::Handle<i::WasmMemoryObject> receiver =
+      i::Handle<i::WasmMemoryObject>::cast(Utils::OpenHandle(*args.This()));
+  i::Handle<i::Object> buffer(receiver->buffer(), i_isolate);
   DCHECK(buffer->IsJSArrayBuffer());
   v8::ReturnValue<v8::Value> return_value = args.GetReturnValue();
   return_value.Set(Utils::ToLocal(buffer));
@@ -586,20 +888,23 @@ void WebAssemblyMemoryGetBuffer(
 static i::Handle<i::FunctionTemplateInfo> NewTemplate(i::Isolate* i_isolate,
                                                       FunctionCallback func) {
   Isolate* isolate = reinterpret_cast<Isolate*>(i_isolate);
-  Local<FunctionTemplate> local = FunctionTemplate::New(isolate, func);
-  return v8::Utils::OpenHandle(*local);
+  Local<FunctionTemplate> templ = FunctionTemplate::New(isolate, func);
+  templ->ReadOnlyPrototype();
+  return v8::Utils::OpenHandle(*templ);
 }
 
 namespace internal {
 
 Handle<JSFunction> InstallFunc(Isolate* isolate, Handle<JSObject> object,
-                               const char* str, FunctionCallback func) {
+                               const char* str, FunctionCallback func,
+                               int length = 0) {
   Handle<String> name = v8_str(isolate, str);
   Handle<FunctionTemplateInfo> temp = NewTemplate(isolate, func);
   Handle<JSFunction> function =
       ApiNatives::InstantiateFunction(temp).ToHandleChecked();
-  PropertyAttributes attributes =
-      static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
+  JSFunction::SetName(function, name, isolate->factory()->empty_string());
+  function->shared()->set_length(length);
+  PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
   JSObject::AddProperty(object, name, function, attributes);
   return function;
 }
@@ -611,27 +916,46 @@ Handle<JSFunction> InstallGetter(Isolate* isolate, Handle<JSObject> object,
   Handle<JSFunction> function =
       ApiNatives::InstantiateFunction(temp).ToHandleChecked();
   v8::PropertyAttribute attributes =
-      static_cast<v8::PropertyAttribute>(v8::DontDelete | v8::ReadOnly);
+      static_cast<v8::PropertyAttribute>(v8::DontEnum);
   Utils::ToLocal(object)->SetAccessorProperty(Utils::ToLocal(name),
                                               Utils::ToLocal(function),
                                               Local<Function>(), attributes);
   return function;
 }
 
-void WasmJs::InstallWasmModuleSymbolIfNeeded(Isolate* isolate,
-                                             Handle<JSGlobalObject> global,
-                                             Handle<Context> context) {
-  if (!context->get(Context::WASM_MODULE_SYM_INDEX)->IsSymbol() ||
-      !context->get(Context::WASM_INSTANCE_SYM_INDEX)->IsSymbol()) {
-    InstallWasmMapsIfNeeded(isolate, isolate->native_context());
-    InstallWasmConstructors(isolate, isolate->global_object(),
-                            isolate->native_context());
-  }
-}
+void WasmJs::Install(Isolate* isolate) {
+  Handle<JSGlobalObject> global = isolate->global_object();
+  Handle<Context> context(global->native_context(), isolate);
+  // TODO(titzer): once FLAG_expose_wasm is gone, this should become a DCHECK.
+  if (context->get(Context::WASM_FUNCTION_MAP_INDEX)->IsMap()) return;
+
+  // Install Maps.
+
+  // TODO(titzer): Also make one for strict mode functions?
+  Handle<Map> prev_map = Handle<Map>(context->sloppy_function_map(), isolate);
+
+  InstanceType instance_type = prev_map->instance_type();
+  int internal_fields = JSObject::GetInternalFieldCount(*prev_map);
+  CHECK_EQ(0, internal_fields);
+  int pre_allocated =
+      prev_map->GetInObjectProperties() - prev_map->unused_property_fields();
+  int instance_size = 0;
+  int in_object_properties = 0;
+  int wasm_internal_fields = internal_fields + 1  // module instance object
+      + 1                  // function arity
+      + 1;                 // function signature
+  JSFunction::CalculateInstanceSizeHelper(instance_type, wasm_internal_fields,
+                                          0, &instance_size,
+                                          &in_object_properties);
+
+  int unused_property_fields = in_object_properties - pre_allocated;
+  Handle<Map> map = Map::CopyInitialMap(
+      prev_map, instance_size, in_object_properties, unused_property_fields);
+
+  context->set_wasm_function_map(*map);
+
+  // Install symbols.
 
-void WasmJs::InstallWasmConstructors(Isolate* isolate,
-                                     Handle<JSGlobalObject> global,
-                                     Handle<Context> context) {
   Factory* factory = isolate->factory();
   // Create private symbols.
   Handle<Symbol> module_sym = factory->NewPrivateSymbol();
@@ -646,7 +970,9 @@ void WasmJs::InstallWasmConstructors(Isolate* isolate,
   Handle<Symbol> memory_sym = factory->NewPrivateSymbol();
   context->set_wasm_memory_sym(*memory_sym);
 
-  // Bind the WebAssembly object.
+  // Install the JS API.
+
+  // Setup WebAssembly
   Handle<String> name = v8_str(isolate, "WebAssembly");
   Handle<JSFunction> cons = factory->NewFunction(name);
   JSFunction::SetInstancePrototype(
@@ -655,118 +981,103 @@ void WasmJs::InstallWasmConstructors(Isolate* isolate,
   Handle<JSObject> webassembly = factory->NewJSObject(cons, TENURED);
   PropertyAttributes attributes = static_cast<PropertyAttributes>(DONT_ENUM);
   JSObject::AddProperty(global, name, webassembly, attributes);
-
-  // Setup compile
-  InstallFunc(isolate, webassembly, "compile", WebAssemblyCompile);
-
-  // Setup compile
-  InstallFunc(isolate, webassembly, "validate", WebAssemblyValidate);
+  PropertyAttributes ro_attributes =
+      static_cast<PropertyAttributes>(DONT_ENUM | READ_ONLY);
+  JSObject::AddProperty(webassembly, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly"), ro_attributes);
+  InstallFunc(isolate, webassembly, "compile", WebAssemblyCompile, 1);
+  InstallFunc(isolate, webassembly, "validate", WebAssemblyValidate, 1);
+  InstallFunc(isolate, webassembly, "instantiate", WebAssemblyInstantiate, 1);
 
   // Setup Module
   Handle<JSFunction> module_constructor =
-      InstallFunc(isolate, webassembly, "Module", WebAssemblyModule);
+      InstallFunc(isolate, webassembly, "Module", WebAssemblyModule, 1);
   context->set_wasm_module_constructor(*module_constructor);
   Handle<JSObject> module_proto =
       factory->NewJSObject(module_constructor, TENURED);
-  i::Handle<i::Map> map = isolate->factory()->NewMap(
-      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize +
+  i::Handle<i::Map> module_map = isolate->factory()->NewMap(
+      i::JS_API_OBJECT_TYPE, i::JSObject::kHeaderSize +
                              WasmModuleObject::kFieldCount * i::kPointerSize);
-  JSFunction::SetInitialMap(module_constructor, map, module_proto);
+  JSFunction::SetInitialMap(module_constructor, module_map, module_proto);
+  InstallFunc(isolate, module_constructor, "imports", WebAssemblyModuleImports,
+              1);
+  InstallFunc(isolate, module_constructor, "exports", WebAssemblyModuleExports,
+              1);
+  InstallFunc(isolate, module_constructor, "customSections",
+              WebAssemblyModuleCustomSections, 2);
   JSObject::AddProperty(module_proto, isolate->factory()->constructor_string(),
                         module_constructor, DONT_ENUM);
+  JSObject::AddProperty(module_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Module"), ro_attributes);
 
   // Setup Instance
   Handle<JSFunction> instance_constructor =
-      InstallFunc(isolate, webassembly, "Instance", WebAssemblyInstance);
+      InstallFunc(isolate, webassembly, "Instance", WebAssemblyInstance, 1);
   context->set_wasm_instance_constructor(*instance_constructor);
+  Handle<JSObject> instance_proto =
+      factory->NewJSObject(instance_constructor, TENURED);
+  i::Handle<i::Map> instance_map = isolate->factory()->NewMap(
+      i::JS_API_OBJECT_TYPE, i::JSObject::kHeaderSize +
+                             WasmInstanceObject::kFieldCount * i::kPointerSize);
+  JSFunction::SetInitialMap(instance_constructor, instance_map, instance_proto);
+  JSObject::AddProperty(instance_proto,
+                        isolate->factory()->constructor_string(),
+                        instance_constructor, DONT_ENUM);
+  JSObject::AddProperty(instance_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Instance"), ro_attributes);
 
   // Setup Table
   Handle<JSFunction> table_constructor =
-      InstallFunc(isolate, webassembly, "Table", WebAssemblyTable);
+      InstallFunc(isolate, webassembly, "Table", WebAssemblyTable, 1);
   context->set_wasm_table_constructor(*table_constructor);
   Handle<JSObject> table_proto =
       factory->NewJSObject(table_constructor, TENURED);
-  map = isolate->factory()->NewMap(
-      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize +
+  i::Handle<i::Map> table_map = isolate->factory()->NewMap(
+      i::JS_API_OBJECT_TYPE, i::JSObject::kHeaderSize +
                              WasmTableObject::kFieldCount * i::kPointerSize);
-  JSFunction::SetInitialMap(table_constructor, map, table_proto);
+  JSFunction::SetInitialMap(table_constructor, table_map, table_proto);
   JSObject::AddProperty(table_proto, isolate->factory()->constructor_string(),
                         table_constructor, DONT_ENUM);
   InstallGetter(isolate, table_proto, "length", WebAssemblyTableGetLength);
-  InstallFunc(isolate, table_proto, "grow", WebAssemblyTableGrow);
-  InstallFunc(isolate, table_proto, "get", WebAssemblyTableGet);
-  InstallFunc(isolate, table_proto, "set", WebAssemblyTableSet);
+  InstallFunc(isolate, table_proto, "grow", WebAssemblyTableGrow, 1);
+  InstallFunc(isolate, table_proto, "get", WebAssemblyTableGet, 1);
+  InstallFunc(isolate, table_proto, "set", WebAssemblyTableSet, 2);
+  JSObject::AddProperty(table_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Table"), ro_attributes);
 
   // Setup Memory
   Handle<JSFunction> memory_constructor =
-      InstallFunc(isolate, webassembly, "Memory", WebAssemblyMemory);
+      InstallFunc(isolate, webassembly, "Memory", WebAssemblyMemory, 1);
   context->set_wasm_memory_constructor(*memory_constructor);
   Handle<JSObject> memory_proto =
       factory->NewJSObject(memory_constructor, TENURED);
-  map = isolate->factory()->NewMap(
-      i::JS_OBJECT_TYPE, i::JSObject::kHeaderSize +
+  i::Handle<i::Map> memory_map = isolate->factory()->NewMap(
+      i::JS_API_OBJECT_TYPE, i::JSObject::kHeaderSize +
                              WasmMemoryObject::kFieldCount * i::kPointerSize);
-  JSFunction::SetInitialMap(memory_constructor, map, memory_proto);
+  JSFunction::SetInitialMap(memory_constructor, memory_map, memory_proto);
   JSObject::AddProperty(memory_proto, isolate->factory()->constructor_string(),
                         memory_constructor, DONT_ENUM);
-  InstallFunc(isolate, memory_proto, "grow", WebAssemblyMemoryGrow);
+  InstallFunc(isolate, memory_proto, "grow", WebAssemblyMemoryGrow, 1);
   InstallGetter(isolate, memory_proto, "buffer", WebAssemblyMemoryGetBuffer);
+  JSObject::AddProperty(memory_proto, factory->to_string_tag_symbol(),
+                        v8_str(isolate, "WebAssembly.Memory"), ro_attributes);
 
   // Setup errors
-  attributes = static_cast<PropertyAttributes>(DONT_DELETE | READ_ONLY);
+  attributes = static_cast<PropertyAttributes>(DONT_ENUM);
   Handle<JSFunction> compile_error(
       isolate->native_context()->wasm_compile_error_function());
   JSObject::AddProperty(webassembly, isolate->factory()->CompileError_string(),
                         compile_error, attributes);
+  Handle<JSFunction> link_error(
+      isolate->native_context()->wasm_link_error_function());
+  JSObject::AddProperty(webassembly, isolate->factory()->LinkError_string(),
+                        link_error, attributes);
   Handle<JSFunction> runtime_error(
       isolate->native_context()->wasm_runtime_error_function());
   JSObject::AddProperty(webassembly, isolate->factory()->RuntimeError_string(),
                         runtime_error, attributes);
 }
 
-void WasmJs::Install(Isolate* isolate, Handle<JSGlobalObject> global) {
-  if (!FLAG_expose_wasm && !FLAG_validate_asm) {
-    return;
-  }
-
-  // Setup wasm function map.
-  Handle<Context> context(global->native_context(), isolate);
-  InstallWasmMapsIfNeeded(isolate, context);
-
-  if (FLAG_expose_wasm) {
-    InstallWasmConstructors(isolate, global, context);
-  }
-}
-
-void WasmJs::InstallWasmMapsIfNeeded(Isolate* isolate,
-                                     Handle<Context> context) {
-  if (!context->get(Context::WASM_FUNCTION_MAP_INDEX)->IsMap()) {
-    // TODO(titzer): Move this to bootstrapper.cc??
-    // TODO(titzer): Also make one for strict mode functions?
-    Handle<Map> prev_map = Handle<Map>(context->sloppy_function_map(), isolate);
-
-    InstanceType instance_type = prev_map->instance_type();
-    int internal_fields = JSObject::GetInternalFieldCount(*prev_map);
-    CHECK_EQ(0, internal_fields);
-    int pre_allocated =
-        prev_map->GetInObjectProperties() - prev_map->unused_property_fields();
-    int instance_size = 0;
-    int in_object_properties = 0;
-    int wasm_internal_fields = internal_fields + 1  // module instance object
-                               + 1                  // function arity
-                               + 1;                 // function signature
-    JSFunction::CalculateInstanceSizeHelper(instance_type, wasm_internal_fields,
-                                            0, &instance_size,
-                                            &in_object_properties);
-
-    int unused_property_fields = in_object_properties - pre_allocated;
-    Handle<Map> map = Map::CopyInitialMap(
-        prev_map, instance_size, in_object_properties, unused_property_fields);
-
-    context->set_wasm_function_map(*map);
-  }
-}
-
 static bool HasBrand(i::Handle<i::Object> value, i::Handle<i::Symbol> symbol) {
   if (value->IsJSObject()) {
     i::Handle<i::JSObject> object = i::Handle<i::JSObject>::cast(value);
diff --git a/deps/v8/src/wasm/wasm-js.h b/deps/v8/src/wasm/wasm-js.h
index f5b9596ee2..05d5ea3061 100644
--- a/deps/v8/src/wasm/wasm-js.h
+++ b/deps/v8/src/wasm/wasm-js.h
@@ -13,16 +13,7 @@ namespace internal {
 // Exposes a WASM API to JavaScript through the V8 API.
 class WasmJs {
  public:
-  static void Install(Isolate* isolate, Handle<JSGlobalObject> global_object);
-
-  V8_EXPORT_PRIVATE static void InstallWasmModuleSymbolIfNeeded(
-      Isolate* isolate, Handle<JSGlobalObject> global, Handle<Context> context);
-
-  V8_EXPORT_PRIVATE static void InstallWasmMapsIfNeeded(
-      Isolate* isolate, Handle<Context> context);
-  static void InstallWasmConstructors(Isolate* isolate,
-                                      Handle<JSGlobalObject> global,
-                                      Handle<Context> context);
+  V8_EXPORT_PRIVATE static void Install(Isolate* isolate);
 
   // WebAssembly.Table.
   static bool IsWasmTableObject(Isolate* isolate, Handle<Object> value);
diff --git a/deps/v8/src/wasm/wasm-limits.h b/deps/v8/src/wasm/wasm-limits.h
new file mode 100644
index 0000000000..4c7455adc5
--- /dev/null
+++ b/deps/v8/src/wasm/wasm-limits.h
@@ -0,0 +1,45 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_WASM_WASM_LIMITS_H_
+#define V8_WASM_WASM_LIMITS_H_
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+// The following limits are imposed by V8 on WebAssembly modules.
+// The limits are agreed upon with other engines for consistency.
+const size_t kV8MaxWasmTypes = 1000000;
+const size_t kV8MaxWasmFunctions = 1000000;
+const size_t kV8MaxWasmImports = 100000;
+const size_t kV8MaxWasmExports = 100000;
+const size_t kV8MaxWasmGlobals = 1000000;
+const size_t kV8MaxWasmDataSegments = 100000;
+const size_t kV8MaxWasmMemoryPages = 16384;  // = 1 GiB
+const size_t kV8MaxWasmStringSize = 100000;
+const size_t kV8MaxWasmModuleSize = 1024 * 1024 * 1024;  // = 1 GiB
+const size_t kV8MaxWasmFunctionSize = 128 * 1024;
+const size_t kV8MaxWasmFunctionLocals = 50000;
+const size_t kV8MaxWasmFunctionParams = 1000;
+const size_t kV8MaxWasmFunctionMultiReturns = 1000;
+const size_t kV8MaxWasmFunctionReturns = 1;
+const size_t kV8MaxWasmTableSize = 10000000;
+const size_t kV8MaxWasmTableEntries = 10000000;
+const size_t kV8MaxWasmTables = 1;
+const size_t kV8MaxWasmMemories = 1;
+
+const size_t kSpecMaxWasmMemoryPages = 65536;
+const size_t kSpecMaxWasmTableSize = 0xFFFFFFFFu;
+
+const uint64_t kWasmMaxHeapOffset =
+    static_cast<uint64_t>(
+        std::numeric_limits<uint32_t>::max())  // maximum base value
+    + std::numeric_limits<uint32_t>::max();    // maximum index value
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_WASM_WASM_LIMITS_H_
diff --git a/deps/v8/src/wasm/wasm-macro-gen.h b/deps/v8/src/wasm/wasm-macro-gen.h
index ce2f843e71..1ec9ee80ff 100644
--- a/deps/v8/src/wasm/wasm-macro-gen.h
+++ b/deps/v8/src/wasm/wasm-macro-gen.h
@@ -59,6 +59,7 @@
 // Control.
 //------------------------------------------------------------------------------
 #define WASM_NOP kExprNop
+#define WASM_END kExprEnd
 
 #define ARITY_0 0
 #define ARITY_1 1
@@ -71,13 +72,13 @@
 #define WASM_BLOCK(...) kExprBlock, kLocalVoid, __VA_ARGS__, kExprEnd
 
 #define WASM_BLOCK_T(t, ...)                                       \
-  kExprBlock, static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t)), \
+  kExprBlock, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), \
       __VA_ARGS__, kExprEnd
 
 #define WASM_BLOCK_TT(t1, t2, ...)                                       \
   kExprBlock, kMultivalBlock, 0,                                         \
-      static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t1)),              \
-      static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t2)), __VA_ARGS__, \
+      static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t1)),              \
+      static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t2)), __VA_ARGS__, \
       kExprEnd
 
 #define WASM_BLOCK_I(...) kExprBlock, kLocalI32, __VA_ARGS__, kExprEnd
@@ -99,13 +100,13 @@
   cond, kExprIf, kLocalVoid, tstmt, kExprElse, fstmt, kExprEnd
 
 #define WASM_IF_ELSE_T(t, cond, tstmt, fstmt)                                \
-  cond, kExprIf, static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t)), tstmt, \
+  cond, kExprIf, static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t)), tstmt, \
       kExprElse, fstmt, kExprEnd
 
 #define WASM_IF_ELSE_TT(t1, t2, cond, tstmt, fstmt)                           \
   cond, kExprIf, kMultivalBlock, 0,                                           \
-      static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t1)),                   \
-      static_cast<byte>(WasmOpcodes::LocalTypeCodeFor(t2)), tstmt, kExprElse, \
+      static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t1)),                   \
+      static_cast<byte>(WasmOpcodes::ValueTypeCodeFor(t2)), tstmt, kExprElse, \
       fstmt, kExprEnd
 
 #define WASM_IF_ELSE_I(cond, tstmt, fstmt) \
@@ -140,9 +141,8 @@
 // Misc expressions.
 //------------------------------------------------------------------------------
 #define WASM_ID(...) __VA_ARGS__
-#define WASM_ZERO kExprI8Const, 0
-#define WASM_ONE kExprI8Const, 1
-#define WASM_I8(val) kExprI8Const, static_cast<byte>(val)
+#define WASM_ZERO kExprI32Const, 0
+#define WASM_ONE kExprI32Const, 1
 
 #define I32V_MIN(length) -(1 << (6 + (7 * ((length) - 1))))
 #define I32V_MAX(length) ((1 << (6 + (7 * ((length) - 1)))) - 1)
@@ -195,7 +195,7 @@ class LocalDeclEncoder {
     pos = WriteUint32v(buffer, pos, static_cast<uint32_t>(local_decls.size()));
     for (size_t i = 0; i < local_decls.size(); ++i) {
       pos = WriteUint32v(buffer, pos, local_decls[i].first);
-      buffer[pos++] = WasmOpcodes::LocalTypeCodeFor(local_decls[i].second);
+      buffer[pos++] = WasmOpcodes::ValueTypeCodeFor(local_decls[i].second);
     }
     DCHECK_EQ(Size(), pos);
     return pos;
@@ -203,7 +203,7 @@ class LocalDeclEncoder {
 
   // Add locals declarations to this helper. Return the index of the newly added
   // local(s), with an optional adjustment for the parameters.
-  uint32_t AddLocals(uint32_t count, LocalType type) {
+  uint32_t AddLocals(uint32_t count, ValueType type) {
     uint32_t result =
         static_cast<uint32_t>(total + (sig ? sig->parameter_count() : 0));
     total += count;
@@ -211,7 +211,7 @@ class LocalDeclEncoder {
       count += local_decls.back().first;
       local_decls.pop_back();
     }
-    local_decls.push_back(std::pair<uint32_t, LocalType>(count, type));
+    local_decls.push_back(std::pair<uint32_t, ValueType>(count, type));
     return result;
   }
 
@@ -227,7 +227,7 @@ class LocalDeclEncoder {
 
  private:
   FunctionSig* sig;
-  ZoneVector<std::pair<uint32_t, LocalType>> local_decls;
+  ZoneVector<std::pair<uint32_t, ValueType>> local_decls;
   size_t total;
 
   size_t SizeofUint32v(uint32_t val) const {
@@ -447,19 +447,22 @@ class LocalDeclEncoder {
 #define WASM_WHILE(x, y)                                              \
   kExprLoop, kLocalVoid, x, kExprIf, kLocalVoid, y, kExprBr, DEPTH_1, \
       kExprEnd, kExprEnd
-#define WASM_INC_LOCAL(index)                                            \
-  kExprGetLocal, static_cast<byte>(index), kExprI8Const, 1, kExprI32Add, \
+#define WASM_INC_LOCAL(index)                                             \
+  kExprGetLocal, static_cast<byte>(index), kExprI32Const, 1, kExprI32Add, \
       kExprTeeLocal, static_cast<byte>(index)
 #define WASM_INC_LOCAL_BYV(index, count)                    \
-  kExprGetLocal, static_cast<byte>(index), kExprI8Const,    \
+  kExprGetLocal, static_cast<byte>(index), kExprI32Const,   \
       static_cast<byte>(count), kExprI32Add, kExprTeeLocal, \
       static_cast<byte>(index)
 #define WASM_INC_LOCAL_BY(index, count)                     \
-  kExprGetLocal, static_cast<byte>(index), kExprI8Const,    \
+  kExprGetLocal, static_cast<byte>(index), kExprI32Const,   \
       static_cast<byte>(count), kExprI32Add, kExprSetLocal, \
       static_cast<byte>(index)
 #define WASM_UNOP(opcode, x) x, static_cast<byte>(opcode)
 #define WASM_BINOP(opcode, x, y) x, y, static_cast<byte>(opcode)
+#define WASM_SIMD_UNOP(opcode, x) x, kSimdPrefix, static_cast<byte>(opcode)
+#define WASM_SIMD_BINOP(opcode, x, y) \
+  x, y, kSimdPrefix, static_cast<byte>(opcode)
 
 //------------------------------------------------------------------------------
 // Int32 operations
@@ -621,14 +624,31 @@ class LocalDeclEncoder {
 //------------------------------------------------------------------------------
 // Simd Operations.
 //------------------------------------------------------------------------------
-#define WASM_SIMD_I32x4_SPLAT(x) x, kSimdPrefix, kExprI32x4Splat & 0xff
-#define WASM_SIMD_I32x4_EXTRACT_LANE(lane, x) \
-  x, kSimdPrefix, kExprI32x4ExtractLane & 0xff, static_cast<byte>(lane)
-#define WASM_SIMD_I32x4_ADD(x, y) x, y, kSimdPrefix, kExprI32x4Add & 0xff
 #define WASM_SIMD_F32x4_SPLAT(x) x, kSimdPrefix, kExprF32x4Splat & 0xff
 #define WASM_SIMD_F32x4_EXTRACT_LANE(lane, x) \
   x, kSimdPrefix, kExprF32x4ExtractLane & 0xff, static_cast<byte>(lane)
+#define WASM_SIMD_F32x4_REPLACE_LANE(lane, x, y) \
+  x, y, kSimdPrefix, kExprF32x4ReplaceLane & 0xff, static_cast<byte>(lane)
+#define WASM_SIMD_F32x4_FROM_I32x4(x) \
+  x, kSimdPrefix, kExprF32x4FromInt32x4 & 0xff
+#define WASM_SIMD_F32x4_FROM_U32x4(x) \
+  x, kSimdPrefix, kExprF32x4FromUint32x4 & 0xff
 #define WASM_SIMD_F32x4_ADD(x, y) x, y, kSimdPrefix, kExprF32x4Add & 0xff
+#define WASM_SIMD_F32x4_SUB(x, y) x, y, kSimdPrefix, kExprF32x4Sub & 0xff
+
+#define WASM_SIMD_I32x4_SPLAT(x) x, kSimdPrefix, kExprI32x4Splat & 0xff
+#define WASM_SIMD_I32x4_EXTRACT_LANE(lane, x) \
+  x, kSimdPrefix, kExprI32x4ExtractLane & 0xff, static_cast<byte>(lane)
+#define WASM_SIMD_I32x4_REPLACE_LANE(lane, x, y) \
+  x, y, kSimdPrefix, kExprI32x4ReplaceLane & 0xff, static_cast<byte>(lane)
+#define WASM_SIMD_I32x4_FROM_F32x4(x) \
+  x, kSimdPrefix, kExprI32x4FromFloat32x4 & 0xff
+#define WASM_SIMD_U32x4_FROM_F32x4(x) \
+  x, kSimdPrefix, kExprUi32x4FromFloat32x4 & 0xff
+#define WASM_SIMD_S32x4_SELECT(x, y, z) \
+  x, y, z, kSimdPrefix, kExprS32x4Select & 0xff
+#define WASM_SIMD_I32x4_ADD(x, y) x, y, kSimdPrefix, kExprI32x4Add & 0xff
+#define WASM_SIMD_I32x4_SUB(x, y) x, y, kSimdPrefix, kExprI32x4Sub & 0xff
 
 #define SIG_ENTRY_v_v kWasmFunctionTypeForm, 0, 0
 #define SIZEOF_SIG_ENTRY_v_v 3
diff --git a/deps/v8/src/wasm/wasm-module-builder.cc b/deps/v8/src/wasm/wasm-module-builder.cc
index 290e98ecf8..cd83d46d3e 100644
--- a/deps/v8/src/wasm/wasm-module-builder.cc
+++ b/deps/v8/src/wasm/wasm-module-builder.cc
@@ -8,7 +8,7 @@
 #include "src/v8.h"
 #include "src/zone/zone-containers.h"
 
-#include "src/wasm/ast-decoder.h"
+#include "src/wasm/function-body-decoder.h"
 #include "src/wasm/leb-helper.h"
 #include "src/wasm/wasm-macro-gen.h"
 #include "src/wasm/wasm-module-builder.h"
@@ -50,11 +50,10 @@ WasmFunctionBuilder::WasmFunctionBuilder(WasmModuleBuilder* builder)
     : builder_(builder),
       locals_(builder->zone()),
       signature_index_(0),
-      exported_(0),
       func_index_(static_cast<uint32_t>(builder->functions_.size())),
       body_(builder->zone()),
       name_(builder->zone()),
-      exported_name_(builder->zone()),
+      exported_names_(builder->zone()),
       i32_temps_(builder->zone()),
       i64_temps_(builder->zone()),
       f32_temps_(builder->zone()),
@@ -77,7 +76,7 @@ void WasmFunctionBuilder::SetSignature(FunctionSig* sig) {
   signature_index_ = builder_->AddSignature(sig);
 }
 
-uint32_t WasmFunctionBuilder::AddLocal(LocalType type) {
+uint32_t WasmFunctionBuilder::AddLocal(ValueType type) {
   DCHECK(locals_.has_sig());
   return locals_.AddLocals(1, type);
 }
@@ -123,10 +122,10 @@ void WasmFunctionBuilder::EmitWithVarInt(WasmOpcode opcode,
 }
 
 void WasmFunctionBuilder::EmitI32Const(int32_t value) {
-  // TODO(titzer): variable-length signed and unsigned i32 constants.
-  if (-128 <= value && value <= 127) {
-    EmitWithU8(kExprI8Const, static_cast<byte>(value));
+  if (-64 <= value && value <= 63) {
+    EmitWithU8(kExprI32Const, static_cast<byte>(value & 0x7F));
   } else {
+    // TODO(titzer): variable-length signed and unsigned i32 constants.
     byte code[] = {WASM_I32V_5(value)};
     EmitCode(code, sizeof(code));
   }
@@ -141,12 +140,9 @@ void WasmFunctionBuilder::EmitDirectCallIndex(uint32_t index) {
   EmitCode(code, sizeof(code));
 }
 
-void WasmFunctionBuilder::Export() { exported_ = true; }
-
 void WasmFunctionBuilder::ExportAs(Vector<const char> name) {
-  exported_ = true;
-  exported_name_.resize(name.length());
-  memcpy(exported_name_.data(), name.start(), name.length());
+  exported_names_.push_back(ZoneVector<char>(
+      name.start(), name.start() + name.length(), builder_->zone()));
 }
 
 void WasmFunctionBuilder::SetName(Vector<const char> name) {
@@ -154,8 +150,9 @@ void WasmFunctionBuilder::SetName(Vector<const char> name) {
   memcpy(name_.data(), name.start(), name.length());
 }
 
-void WasmFunctionBuilder::AddAsmWasmOffset(int asm_position) {
-  // We only want to emit one mapping per byte offset:
+void WasmFunctionBuilder::AddAsmWasmOffset(int call_position,
+                                           int to_number_position) {
+  // We only want to emit one mapping per byte offset.
   DCHECK(asm_offsets_.size() == 0 || body_.size() > last_asm_byte_offset_);
 
   DCHECK_LE(body_.size(), kMaxUInt32);
@@ -163,22 +160,31 @@ void WasmFunctionBuilder::AddAsmWasmOffset(int asm_position) {
   asm_offsets_.write_u32v(byte_offset - last_asm_byte_offset_);
   last_asm_byte_offset_ = byte_offset;
 
-  DCHECK_GE(asm_position, 0);
-  asm_offsets_.write_i32v(asm_position - last_asm_source_position_);
-  last_asm_source_position_ = asm_position;
+  DCHECK_GE(call_position, 0);
+  asm_offsets_.write_i32v(call_position - last_asm_source_position_);
+
+  DCHECK_GE(to_number_position, 0);
+  asm_offsets_.write_i32v(to_number_position - call_position);
+  last_asm_source_position_ = to_number_position;
+}
+
+void WasmFunctionBuilder::SetAsmFunctionStartPosition(int position) {
+  DCHECK_EQ(0, asm_func_start_source_position_);
+  DCHECK_LE(0, position);
+  // Must be called before emitting any asm.js source position.
+  DCHECK_EQ(0, asm_offsets_.size());
+  asm_func_start_source_position_ = position;
+  last_asm_source_position_ = position;
 }
 
 void WasmFunctionBuilder::WriteSignature(ZoneBuffer& buffer) const {
   buffer.write_u32v(signature_index_);
 }
 
-void WasmFunctionBuilder::WriteExport(ZoneBuffer& buffer) const {
-  if (exported_) {
-    const ZoneVector<char>* exported_name =
-        exported_name_.size() == 0 ? &name_ : &exported_name_;
-    buffer.write_size(exported_name->size());
-    buffer.write(reinterpret_cast<const byte*>(exported_name->data()),
-                 exported_name->size());
+void WasmFunctionBuilder::WriteExports(ZoneBuffer& buffer) const {
+  for (auto name : exported_names_) {
+    buffer.write_size(name.size());
+    buffer.write(reinterpret_cast<const byte*>(name.data()), name.size());
     buffer.write_u8(kExternalFunction);
     buffer.write_u32v(func_index_ +
                       static_cast<uint32_t>(builder_->imports_.size()));
@@ -204,14 +210,19 @@ void WasmFunctionBuilder::WriteBody(ZoneBuffer& buffer) const {
 }
 
 void WasmFunctionBuilder::WriteAsmWasmOffsetTable(ZoneBuffer& buffer) const {
-  if (asm_offsets_.size() == 0) {
+  if (asm_func_start_source_position_ == 0 && asm_offsets_.size() == 0) {
     buffer.write_size(0);
     return;
   }
-  buffer.write_size(asm_offsets_.size() + kInt32Size);
+  size_t locals_enc_size = LEBHelper::sizeof_u32v(locals_.Size());
+  size_t func_start_size =
+      LEBHelper::sizeof_u32v(asm_func_start_source_position_);
+  buffer.write_size(asm_offsets_.size() + locals_enc_size + func_start_size);
   // Offset of the recorded byte offsets.
   DCHECK_GE(kMaxUInt32, locals_.Size());
-  buffer.write_u32(static_cast<uint32_t>(locals_.Size()));
+  buffer.write_u32v(static_cast<uint32_t>(locals_.Size()));
+  // Start position of the function.
+  buffer.write_u32v(asm_func_start_source_position_);
   buffer.write(asm_offsets_.begin(), asm_offsets_.size());
 }
 
@@ -271,8 +282,15 @@ uint32_t WasmModuleBuilder::AddSignature(FunctionSig* sig) {
   }
 }
 
-void WasmModuleBuilder::AddIndirectFunction(uint32_t index) {
-  indirect_functions_.push_back(index);
+uint32_t WasmModuleBuilder::AllocateIndirectFunctions(uint32_t count) {
+  uint32_t ret = static_cast<uint32_t>(indirect_functions_.size());
+  indirect_functions_.resize(indirect_functions_.size() + count);
+  return ret;
+}
+
+void WasmModuleBuilder::SetIndirectFunction(uint32_t indirect,
+                                            uint32_t direct) {
+  indirect_functions_[indirect] = direct;
 }
 
 uint32_t WasmModuleBuilder::AddImport(const char* name, int name_length,
@@ -285,7 +303,7 @@ void WasmModuleBuilder::MarkStartFunction(WasmFunctionBuilder* function) {
   start_function_index_ = function->func_index();
 }
 
-uint32_t WasmModuleBuilder::AddGlobal(LocalType type, bool exported,
+uint32_t WasmModuleBuilder::AddGlobal(ValueType type, bool exported,
                                       bool mutability,
                                       const WasmInitExpr& init) {
   globals_.push_back({type, exported, mutability, init});
@@ -309,11 +327,11 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
       buffer.write_u8(kWasmFunctionTypeForm);
       buffer.write_size(sig->parameter_count());
       for (size_t j = 0; j < sig->parameter_count(); j++) {
-        buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(sig->GetParam(j)));
+        buffer.write_u8(WasmOpcodes::ValueTypeCodeFor(sig->GetParam(j)));
       }
       buffer.write_size(sig->return_count());
       for (size_t j = 0; j < sig->return_count(); j++) {
-        buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(sig->GetReturn(j)));
+        buffer.write_u8(WasmOpcodes::ValueTypeCodeFor(sig->GetReturn(j)));
       }
     }
     FixupSection(buffer, start);
@@ -324,10 +342,10 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
     size_t start = EmitSection(kImportSectionCode, buffer);
     buffer.write_size(imports_.size());
     for (auto import : imports_) {
-      buffer.write_u32v(import.name_length);  // module name length
-      buffer.write(reinterpret_cast<const byte*>(import.name),  // module name
+      buffer.write_u32v(0);                   // module name length
+      buffer.write_u32v(import.name_length);  // field name length
+      buffer.write(reinterpret_cast<const byte*>(import.name),  // field name
                    import.name_length);
-      buffer.write_u32v(0);  // field name length
       buffer.write_u8(kExternalFunction);
       buffer.write_u32v(import.sig_index);
     }
@@ -341,7 +359,7 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
     buffer.write_size(functions_.size());
     for (auto function : functions_) {
       function->WriteSignature(buffer);
-      if (function->exported()) exports++;
+      exports += function->exported_names_.size();
       if (function->name_.size() > 0) has_names = true;
     }
     FixupSection(buffer, start);
@@ -374,29 +392,29 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
     buffer.write_size(globals_.size());
 
     for (auto global : globals_) {
-      buffer.write_u8(WasmOpcodes::LocalTypeCodeFor(global.type));
+      buffer.write_u8(WasmOpcodes::ValueTypeCodeFor(global.type));
       buffer.write_u8(global.mutability ? 1 : 0);
       switch (global.init.kind) {
         case WasmInitExpr::kI32Const: {
-          DCHECK_EQ(kAstI32, global.type);
+          DCHECK_EQ(kWasmI32, global.type);
           const byte code[] = {WASM_I32V_5(global.init.val.i32_const)};
           buffer.write(code, sizeof(code));
           break;
         }
         case WasmInitExpr::kI64Const: {
-          DCHECK_EQ(kAstI64, global.type);
+          DCHECK_EQ(kWasmI64, global.type);
           const byte code[] = {WASM_I64V_10(global.init.val.i64_const)};
           buffer.write(code, sizeof(code));
           break;
         }
         case WasmInitExpr::kF32Const: {
-          DCHECK_EQ(kAstF32, global.type);
+          DCHECK_EQ(kWasmF32, global.type);
           const byte code[] = {WASM_F32(global.init.val.f32_const)};
           buffer.write(code, sizeof(code));
           break;
         }
         case WasmInitExpr::kF64Const: {
-          DCHECK_EQ(kAstF64, global.type);
+          DCHECK_EQ(kWasmF64, global.type);
           const byte code[] = {WASM_F64(global.init.val.f64_const)};
           buffer.write(code, sizeof(code));
           break;
@@ -410,22 +428,22 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
         default: {
           // No initializer, emit a default value.
           switch (global.type) {
-            case kAstI32: {
+            case kWasmI32: {
               const byte code[] = {WASM_I32V_1(0)};
               buffer.write(code, sizeof(code));
               break;
             }
-            case kAstI64: {
+            case kWasmI64: {
               const byte code[] = {WASM_I64V_1(0)};
               buffer.write(code, sizeof(code));
               break;
             }
-            case kAstF32: {
+            case kWasmF32: {
               const byte code[] = {WASM_F32(0.0)};
               buffer.write(code, sizeof(code));
               break;
             }
-            case kAstF64: {
+            case kWasmF64: {
               const byte code[] = {WASM_F64(0.0)};
               buffer.write(code, sizeof(code));
               break;
@@ -444,7 +462,7 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
   if (exports > 0) {
     size_t start = EmitSection(kExportSectionCode, buffer);
     buffer.write_u32v(exports);
-    for (auto function : functions_) function->WriteExport(buffer);
+    for (auto function : functions_) function->WriteExports(buffer);
     FixupSection(buffer, start);
   }
 
@@ -517,10 +535,8 @@ void WasmModuleBuilder::WriteTo(ZoneBuffer& buffer) const {
     }
     for (auto function : functions_) {
       buffer.write_size(function->name_.size());
-      if (function->name_.size() > 0) {
-        buffer.write(reinterpret_cast<const byte*>(&function->name_[0]),
-                     function->name_.size());
-      }
+      buffer.write(reinterpret_cast<const byte*>(function->name_.data()),
+                   function->name_.size());
       buffer.write_u8(0);
     }
     FixupSection(buffer, start);
@@ -534,6 +550,8 @@ void WasmModuleBuilder::WriteAsmJsOffsetTable(ZoneBuffer& buffer) const {
   for (auto function : functions_) {
     function->WriteAsmWasmOffsetTable(buffer);
   }
+  // Append a 0 to indicate that this is an encoded table.
+  buffer.write_u8(0);
 }
 }  // namespace wasm
 }  // namespace internal
diff --git a/deps/v8/src/wasm/wasm-module-builder.h b/deps/v8/src/wasm/wasm-module-builder.h
index d35313ef47..3258f78d50 100644
--- a/deps/v8/src/wasm/wasm-module-builder.h
+++ b/deps/v8/src/wasm/wasm-module-builder.h
@@ -120,7 +120,7 @@ class V8_EXPORT_PRIVATE WasmFunctionBuilder : public ZoneObject {
  public:
   // Building methods.
   void SetSignature(FunctionSig* sig);
-  uint32_t AddLocal(LocalType type);
+  uint32_t AddLocal(ValueType type);
   void EmitVarInt(uint32_t val);
   void EmitCode(const byte* code, uint32_t code_size);
   void Emit(WasmOpcode opcode);
@@ -132,17 +132,16 @@ class V8_EXPORT_PRIVATE WasmFunctionBuilder : public ZoneObject {
   void EmitWithU8U8(WasmOpcode opcode, const byte imm1, const byte imm2);
   void EmitWithVarInt(WasmOpcode opcode, uint32_t immediate);
   void EmitDirectCallIndex(uint32_t index);
-  void Export();
   void ExportAs(Vector<const char> name);
   void SetName(Vector<const char> name);
-  void AddAsmWasmOffset(int asm_position);
+  void AddAsmWasmOffset(int call_position, int to_number_position);
+  void SetAsmFunctionStartPosition(int position);
 
   void WriteSignature(ZoneBuffer& buffer) const;
-  void WriteExport(ZoneBuffer& buffer) const;
+  void WriteExports(ZoneBuffer& buffer) const;
   void WriteBody(ZoneBuffer& buffer) const;
   void WriteAsmWasmOffsetTable(ZoneBuffer& buffer) const;
 
-  bool exported() { return exported_; }
   uint32_t func_index() { return func_index_; }
   FunctionSig* signature();
 
@@ -159,11 +158,10 @@ class V8_EXPORT_PRIVATE WasmFunctionBuilder : public ZoneObject {
   WasmModuleBuilder* builder_;
   LocalDeclEncoder locals_;
   uint32_t signature_index_;
-  bool exported_;
   uint32_t func_index_;
   ZoneVector<uint8_t> body_;
   ZoneVector<char> name_;
-  ZoneVector<char> exported_name_;
+  ZoneVector<ZoneVector<char>> exported_names_;
   ZoneVector<uint32_t> i32_temps_;
   ZoneVector<uint32_t> i64_temps_;
   ZoneVector<uint32_t> f32_temps_;
@@ -174,22 +172,23 @@ class V8_EXPORT_PRIVATE WasmFunctionBuilder : public ZoneObject {
   ZoneBuffer asm_offsets_;
   uint32_t last_asm_byte_offset_ = 0;
   uint32_t last_asm_source_position_ = 0;
+  uint32_t asm_func_start_source_position_ = 0;
 };
 
 class WasmTemporary {
  public:
-  WasmTemporary(WasmFunctionBuilder* builder, LocalType type) {
+  WasmTemporary(WasmFunctionBuilder* builder, ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         temporary_ = &builder->i32_temps_;
         break;
-      case kAstI64:
+      case kWasmI64:
         temporary_ = &builder->i64_temps_;
         break;
-      case kAstF32:
+      case kWasmF32:
         temporary_ = &builder->f32_temps_;
         break;
-      case kAstF64:
+      case kWasmF64:
         temporary_ = &builder->f64_temps_;
         break;
       default:
@@ -226,11 +225,12 @@ class V8_EXPORT_PRIVATE WasmModuleBuilder : public ZoneObject {
     imports_[index].name_length = name_length;
   }
   WasmFunctionBuilder* AddFunction(FunctionSig* sig = nullptr);
-  uint32_t AddGlobal(LocalType type, bool exported, bool mutability = true,
+  uint32_t AddGlobal(ValueType type, bool exported, bool mutability = true,
                      const WasmInitExpr& init = WasmInitExpr());
   void AddDataSegment(const byte* data, uint32_t size, uint32_t dest);
   uint32_t AddSignature(FunctionSig* sig);
-  void AddIndirectFunction(uint32_t index);
+  uint32_t AllocateIndirectFunctions(uint32_t count);
+  void SetIndirectFunction(uint32_t indirect, uint32_t direct);
   void MarkStartFunction(WasmFunctionBuilder* builder);
 
   // Writing methods.
@@ -256,7 +256,7 @@ class V8_EXPORT_PRIVATE WasmModuleBuilder : public ZoneObject {
   };
 
   struct WasmGlobal {
-    LocalType type;
+    ValueType type;
     bool exported;
     bool mutability;
     WasmInitExpr init;
diff --git a/deps/v8/src/wasm/wasm-module.cc b/deps/v8/src/wasm/wasm-module.cc
index 79b99fe04d..60dda925fa 100644
--- a/deps/v8/src/wasm/wasm-module.cc
+++ b/deps/v8/src/wasm/wasm-module.cc
@@ -4,25 +4,26 @@
 
 #include <memory>
 
+#include "src/assembler-inl.h"
+#include "src/base/adapters.h"
 #include "src/base/atomic-utils.h"
 #include "src/code-stubs.h"
-
-#include "src/macro-assembler.h"
+#include "src/compiler/wasm-compiler.h"
+#include "src/debug/interface-types.h"
 #include "src/objects.h"
 #include "src/property-descriptor.h"
 #include "src/simulator.h"
 #include "src/snapshot/snapshot.h"
 #include "src/v8.h"
 
-#include "src/wasm/ast-decoder.h"
+#include "src/wasm/function-body-decoder.h"
 #include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-js.h"
+#include "src/wasm/wasm-limits.h"
 #include "src/wasm/wasm-module.h"
 #include "src/wasm/wasm-objects.h"
 #include "src/wasm/wasm-result.h"
 
-#include "src/compiler/wasm-compiler.h"
-
 using namespace v8::internal;
 using namespace v8::internal::wasm;
 namespace base = v8::base;
@@ -40,26 +41,11 @@ namespace base = v8::base;
 namespace {
 
 static const int kInvalidSigIndex = -1;
-static const int kPlaceholderMarker = 1000000000;
 
 byte* raw_buffer_ptr(MaybeHandle<JSArrayBuffer> buffer, int offset) {
   return static_cast<byte*>(buffer.ToHandleChecked()->backing_store()) + offset;
 }
 
-MaybeHandle<String> ExtractStringFromModuleBytes(
-    Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
-    uint32_t offset, uint32_t size) {
-  // TODO(wasm): cache strings from modules if it's a performance win.
-  Handle<SeqOneByteString> module_bytes = compiled_module->module_bytes();
-  DCHECK_GE(static_cast<size_t>(module_bytes->length()), offset);
-  DCHECK_GE(static_cast<size_t>(module_bytes->length() - offset), size);
-  Address raw = module_bytes->GetCharsAddress() + offset;
-  if (!unibrow::Utf8::Validate(reinterpret_cast<const byte*>(raw), size))
-    return {};  // UTF8 decoding error for name.
-  return isolate->factory()->NewStringFromUtf8SubString(
-      module_bytes, static_cast<int>(offset), static_cast<int>(size));
-}
-
 void ReplaceReferenceInCode(Handle<Code> code, Handle<Object> old_ref,
                             Handle<Object> new_ref) {
   for (RelocIterator it(*code, 1 << RelocInfo::EMBEDDED_OBJECT); !it.done();
@@ -70,34 +56,74 @@ void ReplaceReferenceInCode(Handle<Code> code, Handle<Object> old_ref,
   }
 }
 
-Handle<JSArrayBuffer> NewArrayBuffer(Isolate* isolate, size_t size) {
-  if (size > (WasmModule::kV8MaxPages * WasmModule::kPageSize)) {
-    // TODO(titzer): lift restriction on maximum memory allocated here.
-    return Handle<JSArrayBuffer>::null();
-  }
-  void* memory = isolate->array_buffer_allocator()->Allocate(size);
-  if (memory == nullptr) {
-    return Handle<JSArrayBuffer>::null();
-  }
+static void MemoryFinalizer(const v8::WeakCallbackInfo<void>& data) {
+  DisallowHeapAllocation no_gc;
+  JSArrayBuffer** p = reinterpret_cast<JSArrayBuffer**>(data.GetParameter());
+  JSArrayBuffer* buffer = *p;
 
-#if DEBUG
-  // Double check the API allocator actually zero-initialized the memory.
-  const byte* bytes = reinterpret_cast<const byte*>(memory);
-  for (size_t i = 0; i < size; ++i) {
-    DCHECK_EQ(0, bytes[i]);
-  }
+  void* memory = buffer->backing_store();
+  base::OS::Free(memory,
+                 RoundUp(kWasmMaxHeapOffset, base::OS::CommitPageSize()));
+
+  data.GetIsolate()->AdjustAmountOfExternalAllocatedMemory(
+      -buffer->byte_length()->Number());
+
+  GlobalHandles::Destroy(reinterpret_cast<Object**>(p));
+}
+
+#if V8_TARGET_ARCH_64_BIT
+const bool kGuardRegionsSupported = true;
+#else
+const bool kGuardRegionsSupported = false;
 #endif
 
-  Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
-  JSArrayBuffer::Setup(buffer, isolate, false, memory, static_cast<int>(size));
-  buffer->set_is_neuterable(false);
-  return buffer;
+bool EnableGuardRegions() {
+  return FLAG_wasm_guard_pages && kGuardRegionsSupported;
+}
+
+void* TryAllocateBackingStore(Isolate* isolate, size_t size,
+                              bool enable_guard_regions, bool& is_external) {
+  is_external = false;
+  // TODO(eholk): Right now enable_guard_regions has no effect on 32-bit
+  // systems. It may be safer to fail instead, given that other code might do
+  // things that would be unsafe if they expected guard pages where there
+  // weren't any.
+  if (enable_guard_regions && kGuardRegionsSupported) {
+    // TODO(eholk): On Windows we want to make sure we don't commit the guard
+    // pages yet.
+
+    // We always allocate the largest possible offset into the heap, so the
+    // addressable memory after the guard page can be made inaccessible.
+    const size_t alloc_size =
+        RoundUp(kWasmMaxHeapOffset, base::OS::CommitPageSize());
+    DCHECK_EQ(0, size % base::OS::CommitPageSize());
+
+    // AllocateGuarded makes the whole region inaccessible by default.
+    void* memory = base::OS::AllocateGuarded(alloc_size);
+    if (memory == nullptr) {
+      return nullptr;
+    }
+
+    // Make the part we care about accessible.
+    base::OS::Unprotect(memory, size);
+
+    reinterpret_cast<v8::Isolate*>(isolate)
+        ->AdjustAmountOfExternalAllocatedMemory(size);
+
+    is_external = true;
+    return memory;
+  } else {
+    void* memory = isolate->array_buffer_allocator()->Allocate(size);
+    return memory;
+  }
 }
 
 void RelocateMemoryReferencesInCode(Handle<FixedArray> code_table,
+                                    uint32_t num_imported_functions,
                                     Address old_start, Address start,
                                     uint32_t prev_size, uint32_t new_size) {
-  for (int i = 0; i < code_table->length(); ++i) {
+  for (int i = static_cast<int>(num_imported_functions);
+       i < code_table->length(); ++i) {
     DCHECK(code_table->get(i)->IsCode());
     Handle<Code> code = Handle<Code>(Code::cast(code_table->get(i)));
     AllowDeferredHandleDereference embedding_raw_address;
@@ -123,52 +149,25 @@ void RelocateGlobals(Handle<FixedArray> code_table, Address old_start,
   }
 }
 
-Handle<Code> CreatePlaceholder(Factory* factory, uint32_t index,
-                               Code::Kind kind) {
-  // Create a placeholder code object and encode the corresponding index in
-  // the {constant_pool_offset} field of the code object.
-  // TODO(titzer): instead of placeholders, use a reloc_info mode.
-  static byte buffer[] = {0, 0, 0, 0};  // fake instructions.
-  static CodeDesc desc = {
-      buffer, arraysize(buffer), arraysize(buffer), 0, 0, nullptr, 0, nullptr};
-  Handle<Code> code = factory->NewCode(desc, Code::KindField::encode(kind),
-                                       Handle<Object>::null());
-  code->set_constant_pool_offset(static_cast<int>(index) + kPlaceholderMarker);
-  return code;
-}
-
-bool LinkFunction(Handle<Code> unlinked,
-                  std::vector<Handle<Code>>& code_table) {
-  bool modified = false;
-  int mode_mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET);
-  AllowDeferredHandleDereference embedding_raw_address;
-  for (RelocIterator it(*unlinked, mode_mask); !it.done(); it.next()) {
-    RelocInfo::Mode mode = it.rinfo()->rmode();
-    if (RelocInfo::IsCodeTarget(mode)) {
-      Code* target =
-          Code::GetCodeFromTargetAddress(it.rinfo()->target_address());
-      if (target->constant_pool_offset() < kPlaceholderMarker) continue;
-      switch (target->kind()) {
-        case Code::WASM_FUNCTION:        // fall through
-        case Code::WASM_TO_JS_FUNCTION:  // fall through
-        case Code::JS_TO_WASM_FUNCTION: {
-          // Patch direct calls to placeholder code objects.
-          uint32_t index = target->constant_pool_offset() - kPlaceholderMarker;
-          Handle<Code> new_target = code_table[index];
-          if (target != *new_target) {
-            it.rinfo()->set_target_address(new_target->instruction_start(),
-                                           UPDATE_WRITE_BARRIER,
-                                           SKIP_ICACHE_FLUSH);
-            modified = true;
-          }
-          break;
-        }
-        default:
-          break;
-      }
+void RelocateTableSizeReferences(Handle<FixedArray> code_table,
+                                 uint32_t old_size, uint32_t new_size) {
+  for (int i = 0; i < code_table->length(); ++i) {
+    DCHECK(code_table->get(i)->IsCode());
+    Handle<Code> code = Handle<Code>(Code::cast(code_table->get(i)));
+    AllowDeferredHandleDereference embedding_raw_address;
+    int mask = 1 << RelocInfo::WASM_FUNCTION_TABLE_SIZE_REFERENCE;
+    for (RelocIterator it(*code, mask); !it.done(); it.next()) {
+      it.rinfo()->update_wasm_function_table_size_reference(old_size, new_size);
     }
   }
-  return modified;
+}
+
+Handle<Code> CreatePlaceholder(Factory* factory, Code::Kind kind) {
+  byte buffer[] = {0, 0, 0, 0};  // fake instructions.
+  CodeDesc desc = {
+      buffer, arraysize(buffer), arraysize(buffer), 0, 0, nullptr, 0, nullptr};
+  return factory->NewCode(desc, Code::KindField::encode(kind),
+                          Handle<Object>::null());
 }
 
 void FlushICache(Isolate* isolate, Handle<FixedArray> code_table) {
@@ -257,7 +256,7 @@ Address GetGlobalStartAddressFromCodeTemplate(Object* undefined,
   Address old_address = nullptr;
   if (instance->has_globals_buffer()) {
     old_address =
-        static_cast<Address>(instance->get_globals_buffer()->backing_store());
+        static_cast<Address>(instance->globals_buffer()->backing_store());
   }
   return old_address;
 }
@@ -265,7 +264,7 @@ Address GetGlobalStartAddressFromCodeTemplate(Object* undefined,
 void InitializeParallelCompilation(
     Isolate* isolate, const std::vector<WasmFunction>& functions,
     std::vector<compiler::WasmCompilationUnit*>& compilation_units,
-    ModuleEnv& module_env, ErrorThrower* thrower) {
+    ModuleBytesEnv& module_env, ErrorThrower* thrower) {
   for (uint32_t i = FLAG_skip_compiling_wasm_funcs; i < functions.size(); ++i) {
     const WasmFunction* func = &functions[i];
     compilation_units[i] =
@@ -329,9 +328,10 @@ void FinishCompilationUnits(
   }
 }
 
-void CompileInParallel(Isolate* isolate, const WasmModule* module,
+void CompileInParallel(Isolate* isolate, ModuleBytesEnv* module_env,
                        std::vector<Handle<Code>>& functions,
-                       ErrorThrower* thrower, ModuleEnv* module_env) {
+                       ErrorThrower* thrower) {
+  const WasmModule* module = module_env->module;
   // Data structures for the parallel compilation.
   std::vector<compiler::WasmCompilationUnit*> compilation_units(
       module->functions.size());
@@ -393,22 +393,23 @@ void CompileInParallel(Isolate* isolate, const WasmModule* module,
   FinishCompilationUnits(executed_units, functions, result_mutex);
 }
 
-void CompileSequentially(Isolate* isolate, const WasmModule* module,
+void CompileSequentially(Isolate* isolate, ModuleBytesEnv* module_env,
                          std::vector<Handle<Code>>& functions,
-                         ErrorThrower* thrower, ModuleEnv* module_env) {
+                         ErrorThrower* thrower) {
   DCHECK(!thrower->error());
 
+  const WasmModule* module = module_env->module;
   for (uint32_t i = FLAG_skip_compiling_wasm_funcs;
        i < module->functions.size(); ++i) {
     const WasmFunction& func = module->functions[i];
     if (func.imported) continue;  // Imports are compiled at instantiation time.
 
-    WasmName str = module->GetName(func.name_offset, func.name_length);
     Handle<Code> code = Handle<Code>::null();
     // Compile the function.
     code = compiler::WasmCompilationUnit::CompileWasmFunction(
         thrower, isolate, module_env, &func);
     if (code.is_null()) {
+      WasmName str = module_env->GetName(&func);
       thrower->CompileError("Compilation of #%d:%.*s failed.", i, str.length(),
                             str.start());
       break;
@@ -418,36 +419,120 @@ void CompileSequentially(Isolate* isolate, const WasmModule* module,
   }
 }
 
-void PatchDirectCalls(Handle<FixedArray> old_functions,
-                      Handle<FixedArray> new_functions, int start) {
-  DCHECK_EQ(new_functions->length(), old_functions->length());
+int ExtractDirectCallIndex(wasm::Decoder& decoder, const byte* pc) {
+  DCHECK_EQ(static_cast<int>(kExprCallFunction), static_cast<int>(*pc));
+  decoder.Reset(pc + 1, pc + 6);
+  uint32_t call_idx = decoder.consume_u32v("call index");
+  DCHECK(decoder.ok());
+  DCHECK_GE(kMaxInt, call_idx);
+  return static_cast<int>(call_idx);
+}
+
+int AdvanceSourcePositionTableIterator(SourcePositionTableIterator& iterator,
+                                       size_t offset_l) {
+  DCHECK_GE(kMaxInt, offset_l);
+  int offset = static_cast<int>(offset_l);
+  DCHECK(!iterator.done());
+  int byte_pos;
+  do {
+    byte_pos = iterator.source_position().ScriptOffset();
+    iterator.Advance();
+  } while (!iterator.done() && iterator.code_offset() <= offset);
+  return byte_pos;
+}
 
+void PatchContext(RelocIterator& it, Context* context) {
+  Object* old = it.rinfo()->target_object();
+  // The only context we use is the native context.
+  DCHECK_IMPLIES(old->IsContext(), old->IsNativeContext());
+  if (!old->IsNativeContext()) return;
+  it.rinfo()->set_target_object(context, UPDATE_WRITE_BARRIER,
+                                SKIP_ICACHE_FLUSH);
+}
+
+void PatchDirectCallsAndContext(Handle<FixedArray> new_functions,
+                                Handle<WasmCompiledModule> compiled_module,
+                                WasmModule* module, int start) {
   DisallowHeapAllocation no_gc;
-  std::map<Code*, Code*> old_to_new_code;
-  for (int i = 0; i < new_functions->length(); ++i) {
-    old_to_new_code.insert(std::make_pair(Code::cast(old_functions->get(i)),
-                                          Code::cast(new_functions->get(i))));
-  }
-  int mode_mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET);
   AllowDeferredHandleDereference embedding_raw_address;
-  for (int i = start; i < new_functions->length(); ++i) {
-    Code* wasm_function = Code::cast(new_functions->get(i));
+  SeqOneByteString* module_bytes = compiled_module->module_bytes();
+  std::vector<WasmFunction>* wasm_functions =
+      &compiled_module->module()->functions;
+  DCHECK_EQ(wasm_functions->size() +
+                compiled_module->module()->num_exported_functions,
+            new_functions->length());
+  DCHECK_EQ(start, compiled_module->module()->num_imported_functions);
+  Context* context = compiled_module->ptr_to_native_context();
+  int mode_mask = RelocInfo::ModeMask(RelocInfo::CODE_TARGET) |
+                  RelocInfo::ModeMask(RelocInfo::EMBEDDED_OBJECT);
+
+  // Allocate decoder outside of the loop and reuse it to decode all function
+  // indexes.
+  wasm::Decoder decoder(nullptr, nullptr);
+  int num_wasm_functions = static_cast<int>(wasm_functions->size());
+  int func_index = start;
+  // Patch all wasm functions.
+  for (; func_index < num_wasm_functions; ++func_index) {
+    Code* wasm_function = Code::cast(new_functions->get(func_index));
+    DCHECK(wasm_function->kind() == Code::WASM_FUNCTION);
+    // Iterate simultaneously over the relocation information and the source
+    // position table. For each call in the reloc info, move the source position
+    // iterator forward to that position to find the byte offset of the
+    // respective call. Then extract the call index from the module wire bytes
+    // to find the new compiled function.
+    SourcePositionTableIterator source_pos_iterator(
+        wasm_function->source_position_table());
+    const byte* func_bytes =
+        module_bytes->GetChars() +
+        compiled_module->module()->functions[func_index].code_start_offset;
     for (RelocIterator it(wasm_function, mode_mask); !it.done(); it.next()) {
-      Code* old_code =
-          Code::GetCodeFromTargetAddress(it.rinfo()->target_address());
-      if (old_code->kind() == Code::WASM_TO_JS_FUNCTION ||
-          old_code->kind() == Code::WASM_FUNCTION) {
-        auto found = old_to_new_code.find(old_code);
-        DCHECK(found != old_to_new_code.end());
-        Code* new_code = found->second;
-        if (new_code != old_code) {
-          it.rinfo()->set_target_address(new_code->instruction_start(),
-                                         UPDATE_WRITE_BARRIER,
-                                         SKIP_ICACHE_FLUSH);
-        }
+      if (RelocInfo::IsEmbeddedObject(it.rinfo()->rmode())) {
+        PatchContext(it, context);
+        continue;
       }
+      DCHECK(RelocInfo::IsCodeTarget(it.rinfo()->rmode()));
+      Code::Kind kind =
+          Code::GetCodeFromTargetAddress(it.rinfo()->target_address())->kind();
+      if (kind != Code::WASM_FUNCTION && kind != Code::WASM_TO_JS_FUNCTION)
+        continue;
+      size_t offset = it.rinfo()->pc() - wasm_function->instruction_start();
+      int byte_pos =
+          AdvanceSourcePositionTableIterator(source_pos_iterator, offset);
+      int called_func_index =
+          ExtractDirectCallIndex(decoder, func_bytes + byte_pos);
+      Code* new_code = Code::cast(new_functions->get(called_func_index));
+      it.rinfo()->set_target_address(new_code->instruction_start(),
+                                     UPDATE_WRITE_BARRIER, SKIP_ICACHE_FLUSH);
     }
   }
+  // Patch all exported functions.
+  for (auto exp : module->export_table) {
+    if (exp.kind != kExternalFunction) continue;
+    Code* export_wrapper = Code::cast(new_functions->get(func_index));
+    DCHECK_EQ(Code::JS_TO_WASM_FUNCTION, export_wrapper->kind());
+    // There must be exactly one call to WASM_FUNCTION or WASM_TO_JS_FUNCTION.
+    int num_wasm_calls = 0;
+    for (RelocIterator it(export_wrapper, mode_mask); !it.done(); it.next()) {
+      if (RelocInfo::IsEmbeddedObject(it.rinfo()->rmode())) {
+        PatchContext(it, context);
+        continue;
+      }
+      DCHECK(RelocInfo::IsCodeTarget(it.rinfo()->rmode()));
+      Code::Kind kind =
+          Code::GetCodeFromTargetAddress(it.rinfo()->target_address())->kind();
+      if (kind != Code::WASM_FUNCTION && kind != Code::WASM_TO_JS_FUNCTION)
+        continue;
+      ++num_wasm_calls;
+      Code* new_code = Code::cast(new_functions->get(exp.index));
+      DCHECK(new_code->kind() == Code::WASM_FUNCTION ||
+             new_code->kind() == Code::WASM_TO_JS_FUNCTION);
+      it.rinfo()->set_target_address(new_code->instruction_start(),
+                                     UPDATE_WRITE_BARRIER, SKIP_ICACHE_FLUSH);
+    }
+    DCHECK_EQ(1, num_wasm_calls);
+    func_index++;
+  }
+  DCHECK_EQ(new_functions->length(), func_index);
 }
 
 static void ResetCompiledModule(Isolate* isolate, WasmInstanceObject* owner,
@@ -456,7 +541,7 @@ static void ResetCompiledModule(Isolate* isolate, WasmInstanceObject* owner,
   Object* undefined = *isolate->factory()->undefined_value();
   uint32_t old_mem_size = compiled_module->mem_size();
   uint32_t default_mem_size = compiled_module->default_mem_size();
-  Object* mem_start = compiled_module->ptr_to_memory();
+  Object* mem_start = compiled_module->maybe_ptr_to_memory();
   Address old_mem_address = nullptr;
   Address globals_start =
       GetGlobalStartAddressFromCodeTemplate(undefined, owner);
@@ -486,7 +571,8 @@ static void ResetCompiledModule(Isolate* isolate, WasmInstanceObject* owner,
   if (fct_obj != nullptr && fct_obj != undefined &&
       (old_mem_size > 0 || globals_start != nullptr || function_tables)) {
     FixedArray* functions = FixedArray::cast(fct_obj);
-    for (int i = 0; i < functions->length(); ++i) {
+    for (int i = compiled_module->num_imported_functions();
+         i < functions->length(); ++i) {
       Code* code = Code::cast(functions->get(i));
       bool changed = false;
       for (RelocIterator it(code, mode_mask); !it.done(); it.next()) {
@@ -518,12 +604,58 @@ static void ResetCompiledModule(Isolate* isolate, WasmInstanceObject* owner,
   compiled_module->reset_memory();
 }
 
+static void MemoryInstanceFinalizer(Isolate* isolate,
+                                    WasmInstanceObject* instance) {
+  DisallowHeapAllocation no_gc;
+  // If the memory object is destroyed, nothing needs to be done here.
+  if (!instance->has_memory_object()) return;
+  Handle<WasmInstanceWrapper> instance_wrapper =
+      handle(instance->instance_wrapper());
+  DCHECK(WasmInstanceWrapper::IsWasmInstanceWrapper(*instance_wrapper));
+  DCHECK(instance_wrapper->has_instance());
+  bool has_prev = instance_wrapper->has_previous();
+  bool has_next = instance_wrapper->has_next();
+  Handle<WasmMemoryObject> memory_object(instance->memory_object());
+
+  if (!has_prev && !has_next) {
+    memory_object->ResetInstancesLink(isolate);
+    return;
+  } else {
+    Handle<WasmInstanceWrapper> next_wrapper, prev_wrapper;
+    if (!has_prev) {
+      Handle<WasmInstanceWrapper> next_wrapper =
+          instance_wrapper->next_wrapper();
+      next_wrapper->reset_previous_wrapper();
+      // As this is the first link in the memory object, destroying
+      // without updating memory object would corrupt the instance chain in
+      // the memory object.
+      memory_object->set_instances_link(*next_wrapper);
+    } else if (!has_next) {
+      instance_wrapper->previous_wrapper()->reset_next_wrapper();
+    } else {
+      DCHECK(has_next && has_prev);
+      Handle<WasmInstanceWrapper> prev_wrapper =
+          instance_wrapper->previous_wrapper();
+      Handle<WasmInstanceWrapper> next_wrapper =
+          instance_wrapper->next_wrapper();
+      prev_wrapper->set_next_wrapper(*next_wrapper);
+      next_wrapper->set_previous_wrapper(*prev_wrapper);
+    }
+    // Reset to avoid dangling pointers
+    instance_wrapper->reset();
+  }
+}
+
 static void InstanceFinalizer(const v8::WeakCallbackInfo<void>& data) {
+  DisallowHeapAllocation no_gc;
   JSObject** p = reinterpret_cast<JSObject**>(data.GetParameter());
   WasmInstanceObject* owner = reinterpret_cast<WasmInstanceObject*>(*p);
-  WasmCompiledModule* compiled_module = owner->get_compiled_module();
-  TRACE("Finalizing %d {\n", compiled_module->instance_id());
   Isolate* isolate = reinterpret_cast<Isolate*>(data.GetIsolate());
+  // If a link to shared memory instances exists, update the list of memory
+  // instances before the instance is destroyed.
+  if (owner->has_instance_wrapper()) MemoryInstanceFinalizer(isolate, owner);
+  WasmCompiledModule* compiled_module = owner->compiled_module();
+  TRACE("Finalizing %d {\n", compiled_module->instance_id());
   DCHECK(compiled_module->has_weak_wasm_module());
   WeakCell* weak_wasm_module = compiled_module->ptr_to_weak_wasm_module();
 
@@ -540,8 +672,8 @@ static void InstanceFinalizer(const v8::WeakCallbackInfo<void>& data) {
     TRACE("}\n");
 
     DCHECK(!current_template->has_weak_prev_instance());
-    WeakCell* next = compiled_module->ptr_to_weak_next_instance();
-    WeakCell* prev = compiled_module->ptr_to_weak_prev_instance();
+    WeakCell* next = compiled_module->maybe_ptr_to_weak_next_instance();
+    WeakCell* prev = compiled_module->maybe_ptr_to_weak_prev_instance();
 
     if (current_template == compiled_module) {
       if (next == nullptr) {
@@ -597,8 +729,81 @@ std::pair<int, int> GetFunctionOffsetAndLength(
           static_cast<int>(func.code_end_offset - func.code_start_offset)};
 }
 
+Handle<Script> CreateWasmScript(Isolate* isolate,
+                                const ModuleWireBytes& wire_bytes) {
+  Handle<Script> script =
+      isolate->factory()->NewScript(isolate->factory()->empty_string());
+  script->set_type(Script::TYPE_WASM);
+
+  int hash = StringHasher::HashSequentialString(
+      reinterpret_cast<const char*>(wire_bytes.module_bytes.start()),
+      wire_bytes.module_bytes.length(), kZeroHashSeed);
+
+  const int kBufferSize = 50;
+  char buffer[kBufferSize];
+  int url_chars = SNPrintF(ArrayVector(buffer), "wasm://wasm/%08x", hash);
+  DCHECK(url_chars >= 0 && url_chars < kBufferSize);
+  MaybeHandle<String> url_str = isolate->factory()->NewStringFromOneByte(
+      Vector<const uint8_t>(reinterpret_cast<uint8_t*>(buffer), url_chars),
+      TENURED);
+  script->set_source_url(*url_str.ToHandleChecked());
+
+  int name_chars = SNPrintF(ArrayVector(buffer), "wasm-%08x", hash);
+  DCHECK(name_chars >= 0 && name_chars < kBufferSize);
+  MaybeHandle<String> name_str = isolate->factory()->NewStringFromOneByte(
+      Vector<const uint8_t>(reinterpret_cast<uint8_t*>(buffer), name_chars),
+      TENURED);
+  script->set_name(*name_str.ToHandleChecked());
+
+  return script;
+}
 }  // namespace
 
+Handle<JSArrayBuffer> wasm::NewArrayBuffer(Isolate* isolate, size_t size,
+                                           bool enable_guard_regions) {
+  if (size > (kV8MaxWasmMemoryPages * WasmModule::kPageSize)) {
+    // TODO(titzer): lift restriction on maximum memory allocated here.
+    return Handle<JSArrayBuffer>::null();
+  }
+
+  enable_guard_regions = enable_guard_regions && kGuardRegionsSupported;
+
+  bool is_external;  // Set by TryAllocateBackingStore
+  void* memory =
+      TryAllocateBackingStore(isolate, size, enable_guard_regions, is_external);
+
+  if (memory == nullptr) {
+    return Handle<JSArrayBuffer>::null();
+  }
+
+#if DEBUG
+  // Double check the API allocator actually zero-initialized the memory.
+  const byte* bytes = reinterpret_cast<const byte*>(memory);
+  for (size_t i = 0; i < size; ++i) {
+    DCHECK_EQ(0, bytes[i]);
+  }
+#endif
+
+  Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
+  JSArrayBuffer::Setup(buffer, isolate, is_external, memory,
+                       static_cast<int>(size));
+  buffer->set_is_neuterable(false);
+  buffer->set_has_guard_region(enable_guard_regions);
+
+  if (is_external) {
+    // We mark the buffer as external if we allocated it here with guard
+    // pages. That means we need to arrange for it to be freed.
+
+    // TODO(eholk): Finalizers may not run when the main thread is shutting
+    // down, which means we may leak memory here.
+    Handle<Object> global_handle = isolate->global_handles()->Create(*buffer);
+    GlobalHandles::MakeWeak(global_handle.location(), global_handle.location(),
+                            &MemoryFinalizer, v8::WeakCallbackType::kFinalizer);
+  }
+
+  return buffer;
+}
+
 const char* wasm::SectionName(WasmSectionCode code) {
   switch (code) {
     case kUnknownSectionCode:
@@ -650,15 +855,12 @@ std::ostream& wasm::operator<<(std::ostream& os, const WasmFunction& function) {
   return os;
 }
 
-std::ostream& wasm::operator<<(std::ostream& os, const WasmFunctionName& pair) {
-  os << "#" << pair.function_->func_index << ":";
-  if (pair.function_->name_offset > 0) {
-    if (pair.module_) {
-      WasmName name = pair.module_->GetName(pair.function_->name_offset,
-                                            pair.function_->name_length);
-      os.write(name.start(), name.length());
-    } else {
-      os << "+" << pair.function_->func_index;
+std::ostream& wasm::operator<<(std::ostream& os, const WasmFunctionName& name) {
+  os << "#" << name.function_->func_index;
+  if (name.function_->name_offset > 0) {
+    if (name.name_.start()) {
+      os << ":";
+      os.write(name.name_.start(), name.name_.length());
     }
   } else {
     os << "?";
@@ -666,16 +868,17 @@ std::ostream& wasm::operator<<(std::ostream& os, const WasmFunctionName& pair) {
   return os;
 }
 
-Object* wasm::GetOwningWasmInstance(Code* code) {
+WasmInstanceObject* wasm::GetOwningWasmInstance(Code* code) {
   DCHECK(code->kind() == Code::WASM_FUNCTION);
   DisallowHeapAllocation no_gc;
   FixedArray* deopt_data = code->deoptimization_data();
   DCHECK_NOT_NULL(deopt_data);
-  DCHECK(deopt_data->length() == 2);
+  DCHECK_EQ(2, deopt_data->length());
   Object* weak_link = deopt_data->get(0);
-  if (!weak_link->IsWeakCell()) return nullptr;
+  DCHECK(weak_link->IsWeakCell());
   WeakCell* cell = WeakCell::cast(weak_link);
-  return cell->value();
+  if (!cell->value()) return nullptr;
+  return WasmInstanceObject::cast(cell->value());
 }
 
 int wasm::GetFunctionCodeOffset(Handle<WasmCompiledModule> compiled_module,
@@ -683,69 +886,41 @@ int wasm::GetFunctionCodeOffset(Handle<WasmCompiledModule> compiled_module,
   return GetFunctionOffsetAndLength(compiled_module, func_index).first;
 }
 
-bool wasm::GetPositionInfo(Handle<WasmCompiledModule> compiled_module,
-                           uint32_t position, Script::PositionInfo* info) {
-  std::vector<WasmFunction>& functions = compiled_module->module()->functions;
-
-  // Binary search for a function containing the given position.
-  int left = 0;                                    // inclusive
-  int right = static_cast<int>(functions.size());  // exclusive
-  if (right == 0) return false;
-  while (right - left > 1) {
-    int mid = left + (right - left) / 2;
-    if (functions[mid].code_start_offset <= position) {
-      left = mid;
-    } else {
-      right = mid;
-    }
-  }
-  // If the found entry does not contains the given position, return false.
-  WasmFunction& func = functions[left];
-  if (position < func.code_start_offset || position >= func.code_end_offset) {
-    return false;
-  }
-
-  info->line = left;
-  info->column = position - func.code_start_offset;
-  info->line_start = func.code_start_offset;
-  info->line_end = func.code_end_offset;
-  return true;
-}
-
-WasmModule::WasmModule(Zone* owned, const byte* module_start)
-    : owned_zone(owned),
-      module_start(module_start),
-      pending_tasks(new base::Semaphore(0)) {}
+WasmModule::WasmModule(Zone* owned)
+    : owned_zone(owned), pending_tasks(new base::Semaphore(0)) {}
 
 MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
     Isolate* isolate, Handle<WasmModuleWrapper> module_wrapper,
-    ErrorThrower* thrower) const {
+    ErrorThrower* thrower, const ModuleWireBytes& wire_bytes,
+    Handle<Script> asm_js_script,
+    Vector<const byte> asm_js_offset_table_bytes) const {
   Factory* factory = isolate->factory();
 
   MaybeHandle<WasmCompiledModule> nothing;
 
   WasmInstance temp_instance(this);
   temp_instance.context = isolate->native_context();
-  temp_instance.mem_size = WasmModule::kPageSize * this->min_mem_pages;
+  temp_instance.mem_size = WasmModule::kPageSize * min_mem_pages;
   temp_instance.mem_start = nullptr;
   temp_instance.globals_start = nullptr;
 
   // Initialize the indirect tables with placeholders.
-  int function_table_count = static_cast<int>(this->function_tables.size());
+  int function_table_count = static_cast<int>(function_tables.size());
   Handle<FixedArray> function_tables =
-      factory->NewFixedArray(function_table_count);
+      factory->NewFixedArray(function_table_count, TENURED);
+  Handle<FixedArray> signature_tables =
+      factory->NewFixedArray(function_table_count, TENURED);
   for (int i = 0; i < function_table_count; ++i) {
-    temp_instance.function_tables[i] = factory->NewFixedArray(0);
+    temp_instance.function_tables[i] = factory->NewFixedArray(1, TENURED);
+    temp_instance.signature_tables[i] = factory->NewFixedArray(1, TENURED);
     function_tables->set(i, *temp_instance.function_tables[i]);
+    signature_tables->set(i, *temp_instance.signature_tables[i]);
   }
 
   HistogramTimerScope wasm_compile_module_time_scope(
       isolate->counters()->wasm_compile_module_time());
 
-  ModuleEnv module_env;
-  module_env.module = this;
-  module_env.instance = &temp_instance;
-  module_env.origin = origin;
+  ModuleBytesEnv module_env(this, &temp_instance, wire_bytes);
 
   // The {code_table} array contains import wrappers and functions (which
   // are both included in {functions.size()}, and export wrappers.
@@ -755,12 +930,11 @@ MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
       factory->NewFixedArray(static_cast<int>(code_table_size), TENURED);
 
   // Initialize the code table with placeholders.
+  Handle<Code> code_placeholder =
+      CreatePlaceholder(factory, Code::WASM_FUNCTION);
   for (uint32_t i = 0; i < functions.size(); ++i) {
-    Code::Kind kind = Code::WASM_FUNCTION;
-    if (i < num_imported_functions) kind = Code::WASM_TO_JS_FUNCTION;
-    Handle<Code> placeholder = CreatePlaceholder(factory, i, kind);
-    code_table->set(static_cast<int>(i), *placeholder);
-    temp_instance.function_code[i] = placeholder;
+    code_table->set(static_cast<int>(i), *code_placeholder);
+    temp_instance.function_code[i] = code_placeholder;
   }
 
   isolate->counters()->wasm_functions_per_module()->AddSample(
@@ -772,14 +946,14 @@ MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
     for (size_t i = 0; i < temp_instance.function_code.size(); ++i) {
       results.push_back(temp_instance.function_code[i]);
     }
-    CompileInParallel(isolate, this, results, thrower, &module_env);
+    CompileInParallel(isolate, &module_env, results, thrower);
 
     for (size_t i = 0; i < results.size(); ++i) {
       temp_instance.function_code[i] = results[i];
     }
   } else {
-    CompileSequentially(isolate, this, temp_instance.function_code, thrower,
-                        &module_env);
+    CompileSequentially(isolate, &module_env, temp_instance.function_code,
+                        thrower);
   }
   if (thrower->error()) return nothing;
 
@@ -788,61 +962,74 @@ MaybeHandle<WasmCompiledModule> WasmModule::CompileFunctions(
        i < temp_instance.function_code.size(); ++i) {
     Code* code = *temp_instance.function_code[i];
     code_table->set(static_cast<int>(i), code);
+    RecordStats(isolate, code);
   }
 
-  // Link the functions in the module.
-  for (size_t i = FLAG_skip_compiling_wasm_funcs;
-       i < temp_instance.function_code.size(); ++i) {
-    Handle<Code> code = temp_instance.function_code[i];
-    bool modified = LinkFunction(code, temp_instance.function_code);
-    if (modified) {
-      // TODO(mtrofin): do we need to flush the cache here?
-      Assembler::FlushICache(isolate, code->instruction_start(),
-                             code->instruction_size());
-    }
-  }
+  // Create heap objects for script, module bytes and asm.js offset table to be
+  // stored in the shared module data.
+  Handle<Script> script;
+  Handle<ByteArray> asm_js_offset_table;
+  if (asm_js_script.is_null()) {
+    script = CreateWasmScript(isolate, wire_bytes);
+  } else {
+    script = asm_js_script;
+    asm_js_offset_table =
+        isolate->factory()->NewByteArray(asm_js_offset_table_bytes.length());
+    asm_js_offset_table->copy_in(0, asm_js_offset_table_bytes.start(),
+                                 asm_js_offset_table_bytes.length());
+  }
+  // TODO(wasm): only save the sections necessary to deserialize a
+  // {WasmModule}. E.g. function bodies could be omitted.
+  Handle<String> module_bytes =
+      factory->NewStringFromOneByte(wire_bytes.module_bytes, TENURED)
+          .ToHandleChecked();
+  DCHECK(module_bytes->IsSeqOneByteString());
+
+  // Create the shared module data.
+  // TODO(clemensh): For the same module (same bytes / same hash), we should
+  // only have one WasmSharedModuleData. Otherwise, we might only set
+  // breakpoints on a (potentially empty) subset of the instances.
+
+  Handle<WasmSharedModuleData> shared = WasmSharedModuleData::New(
+      isolate, module_wrapper, Handle<SeqOneByteString>::cast(module_bytes),
+      script, asm_js_offset_table);
 
   // Create the compiled module object, and populate with compiled functions
   // and information needed at instantiation time. This object needs to be
   // serializable. Instantiation may occur off a deserialized version of this
   // object.
-  Handle<WasmCompiledModule> ret =
-      WasmCompiledModule::New(isolate, module_wrapper);
+  Handle<WasmCompiledModule> ret = WasmCompiledModule::New(isolate, shared);
+  ret->set_num_imported_functions(num_imported_functions);
   ret->set_code_table(code_table);
   ret->set_min_mem_pages(min_mem_pages);
   ret->set_max_mem_pages(max_mem_pages);
   if (function_table_count > 0) {
     ret->set_function_tables(function_tables);
+    ret->set_signature_tables(signature_tables);
     ret->set_empty_function_tables(function_tables);
   }
 
+  // If we created a wasm script, finish it now and make it public to the
+  // debugger.
+  if (asm_js_script.is_null()) {
+    script->set_wasm_compiled_module(*ret);
+    isolate->debug()->OnAfterCompile(script);
+  }
+
   // Compile JS->WASM wrappers for exported functions.
   int func_index = 0;
   for (auto exp : export_table) {
     if (exp.kind != kExternalFunction) continue;
     Handle<Code> wasm_code =
         code_table->GetValueChecked<Code>(isolate, exp.index);
-    Handle<Code> wrapper_code = compiler::CompileJSToWasmWrapper(
-        isolate, &module_env, wasm_code, exp.index);
+    Handle<Code> wrapper_code =
+        compiler::CompileJSToWasmWrapper(isolate, this, wasm_code, exp.index);
     int export_index = static_cast<int>(functions.size() + func_index);
     code_table->set(export_index, *wrapper_code);
+    RecordStats(isolate, *wrapper_code);
     func_index++;
   }
 
-  {
-    // TODO(wasm): only save the sections necessary to deserialize a
-    // {WasmModule}. E.g. function bodies could be omitted.
-    size_t module_bytes_len = module_end - module_start;
-    DCHECK_LE(module_bytes_len, static_cast<size_t>(kMaxInt));
-    Vector<const uint8_t> module_bytes_vec(module_start,
-                                           static_cast<int>(module_bytes_len));
-    Handle<String> module_bytes_string =
-        factory->NewStringFromOneByte(module_bytes_vec, TENURED)
-            .ToHandleChecked();
-    DCHECK(module_bytes_string->IsSeqOneByteString());
-    ret->set_module_bytes(Handle<SeqOneByteString>::cast(module_bytes_string));
-  }
-
   return ret;
 }
 
@@ -876,7 +1063,7 @@ static Handle<Code> UnwrapImportWrapper(Handle<Object> target) {
       code = handle(target);
     }
   }
-  DCHECK(found == 1);
+  DCHECK_EQ(1, found);
   return code;
 }
 
@@ -884,8 +1071,8 @@ static Handle<Code> CompileImportWrapper(Isolate* isolate, int index,
                                          FunctionSig* sig,
                                          Handle<JSReceiver> target,
                                          Handle<String> module_name,
-                                         MaybeHandle<String> import_name) {
-  Handle<Code> code;
+                                         MaybeHandle<String> import_name,
+                                         ModuleOrigin origin) {
   WasmFunction* other_func = GetWasmFunctionForImportWrapper(isolate, target);
   if (other_func) {
     if (sig->Equals(other_func->sig)) {
@@ -898,7 +1085,7 @@ static Handle<Code> CompileImportWrapper(Isolate* isolate, int index,
   } else {
     // Signature mismatch. Compile a new wrapper for the new signature.
     return compiler::CompileWasmToJSWrapper(isolate, target, sig, index,
-                                            module_name, import_name);
+                                            module_name, import_name, origin);
   }
 }
 
@@ -906,11 +1093,13 @@ static void UpdateDispatchTablesInternal(Isolate* isolate,
                                          Handle<FixedArray> dispatch_tables,
                                          int index, WasmFunction* function,
                                          Handle<Code> code) {
-  DCHECK_EQ(0, dispatch_tables->length() % 3);
-  for (int i = 0; i < dispatch_tables->length(); i += 3) {
+  DCHECK_EQ(0, dispatch_tables->length() % 4);
+  for (int i = 0; i < dispatch_tables->length(); i += 4) {
     int table_index = Smi::cast(dispatch_tables->get(i + 1))->value();
-    Handle<FixedArray> dispatch_table(
+    Handle<FixedArray> function_table(
         FixedArray::cast(dispatch_tables->get(i + 2)), isolate);
+    Handle<FixedArray> signature_table(
+        FixedArray::cast(dispatch_tables->get(i + 3)), isolate);
     if (function) {
       // TODO(titzer): the signature might need to be copied to avoid
       // a dangling pointer in the signature map.
@@ -919,12 +1108,12 @@ static void UpdateDispatchTablesInternal(Isolate* isolate,
       int sig_index = static_cast<int>(
           instance->module()->function_tables[table_index].map.FindOrInsert(
               function->sig));
-      dispatch_table->set(index, Smi::FromInt(sig_index));
-      dispatch_table->set(index + (dispatch_table->length() / 2), *code);
+      signature_table->set(index, Smi::FromInt(sig_index));
+      function_table->set(index, *code);
     } else {
       Code* code = nullptr;
-      dispatch_table->set(index, Smi::FromInt(-1));
-      dispatch_table->set(index + (dispatch_table->length() / 2), code);
+      signature_table->set(index, Smi::FromInt(-1));
+      function_table->set(index, code);
     }
   }
 }
@@ -949,17 +1138,27 @@ void wasm::UpdateDispatchTables(Isolate* isolate,
 class WasmInstanceBuilder {
  public:
   WasmInstanceBuilder(Isolate* isolate, ErrorThrower* thrower,
-                      Handle<JSObject> module_object, Handle<JSReceiver> ffi,
-                      Handle<JSArrayBuffer> memory)
+                      Handle<WasmModuleObject> module_object,
+                      Handle<JSReceiver> ffi, Handle<JSArrayBuffer> memory)
       : isolate_(isolate),
+        module_(module_object->compiled_module()->module()),
         thrower_(thrower),
         module_object_(module_object),
         ffi_(ffi),
         memory_(memory) {}
 
   // Build an instance, in all of its glory.
-  MaybeHandle<JSObject> Build() {
-    MaybeHandle<JSObject> nothing;
+  MaybeHandle<WasmInstanceObject> Build() {
+    MaybeHandle<WasmInstanceObject> nothing;
+
+    // Check that an imports argument was provided, if the module requires it.
+    // No point in continuing otherwise.
+    if (!module_->import_table.empty() && ffi_.is_null()) {
+      thrower_->TypeError(
+          "Imports argument must be present and must be an object");
+      return nothing;
+    }
+
     HistogramTimerScope wasm_instantiate_module_time_scope(
         isolate_->counters()->wasm_instantiate_module_time());
     Factory* factory = isolate_->factory();
@@ -982,8 +1181,7 @@ class WasmInstanceBuilder {
       Handle<WasmCompiledModule> original;
       {
         DisallowHeapAllocation no_gc;
-        original = handle(
-            WasmCompiledModule::cast(module_object_->GetInternalField(0)));
+        original = handle(module_object_->compiled_module());
         if (original->has_weak_owning_instance()) {
           owner = handle(WasmInstanceObject::cast(
               original->weak_owning_instance()->value()));
@@ -1032,10 +1230,8 @@ class WasmInstanceBuilder {
               compiled_module_->instance_id());
       }
       compiled_module_->set_code_table(code_table);
+      compiled_module_->set_native_context(isolate_->native_context());
     }
-    module_ = reinterpret_cast<WasmModuleWrapper*>(
-                  *compiled_module_->module_wrapper())
-                  ->get();
 
     //--------------------------------------------------------------------------
     // Allocate the instance object.
@@ -1049,8 +1245,9 @@ class WasmInstanceBuilder {
     MaybeHandle<JSArrayBuffer> old_globals;
     uint32_t globals_size = module_->globals_size;
     if (globals_size > 0) {
+      const bool enable_guard_regions = false;
       Handle<JSArrayBuffer> global_buffer =
-          NewArrayBuffer(isolate_, globals_size);
+          NewArrayBuffer(isolate_, globals_size, enable_guard_regions);
       globals_ = global_buffer;
       if (globals_.is_null()) {
         thrower_->RangeError("Out of memory: wasm globals");
@@ -1072,9 +1269,9 @@ class WasmInstanceBuilder {
         static_cast<int>(module_->function_tables.size());
     table_instances_.reserve(module_->function_tables.size());
     for (int index = 0; index < function_table_count; ++index) {
-      table_instances_.push_back({Handle<WasmTableObject>::null(),
-                                  Handle<FixedArray>::null(),
-                                  Handle<FixedArray>::null()});
+      table_instances_.push_back(
+          {Handle<WasmTableObject>::null(), Handle<FixedArray>::null(),
+           Handle<FixedArray>::null(), Handle<FixedArray>::null()});
     }
 
     //--------------------------------------------------------------------------
@@ -1089,6 +1286,11 @@ class WasmInstanceBuilder {
     InitGlobals();
 
     //--------------------------------------------------------------------------
+    // Set up the indirect function tables for the new instance.
+    //--------------------------------------------------------------------------
+    if (function_table_count > 0) InitializeTables(code_table, instance);
+
+    //--------------------------------------------------------------------------
     // Set up the memory for the new instance.
     //--------------------------------------------------------------------------
     MaybeHandle<JSArrayBuffer> old_memory;
@@ -1099,17 +1301,51 @@ class WasmInstanceBuilder {
     if (!memory_.is_null()) {
       // Set externally passed ArrayBuffer non neuterable.
       memory_->set_is_neuterable(false);
+
+      DCHECK_IMPLIES(EnableGuardRegions(), module_->origin == kAsmJsOrigin ||
+                                               memory_->has_guard_region());
     } else if (min_mem_pages > 0) {
       memory_ = AllocateMemory(min_mem_pages);
       if (memory_.is_null()) return nothing;  // failed to allocate memory
     }
 
+    //--------------------------------------------------------------------------
+    // Check that indirect function table segments are within bounds.
+    //--------------------------------------------------------------------------
+    for (WasmTableInit& table_init : module_->table_inits) {
+      DCHECK(table_init.table_index < table_instances_.size());
+      uint32_t base = EvalUint32InitExpr(table_init.offset);
+      uint32_t table_size =
+          table_instances_[table_init.table_index].function_table->length();
+      if (!in_bounds(base, static_cast<uint32_t>(table_init.entries.size()),
+                     table_size)) {
+        thrower_->LinkError("table initializer is out of bounds");
+        return nothing;
+      }
+    }
+
+    //--------------------------------------------------------------------------
+    // Check that memory segments are within bounds.
+    //--------------------------------------------------------------------------
+    for (WasmDataSegment& seg : module_->data_segments) {
+      uint32_t base = EvalUint32InitExpr(seg.dest_addr);
+      uint32_t mem_size = memory_.is_null()
+          ? 0 : static_cast<uint32_t>(memory_->byte_length()->Number());
+      if (!in_bounds(base, seg.source_size, mem_size)) {
+        thrower_->LinkError("data segment is out of bounds");
+        return nothing;
+      }
+    }
+
+    //--------------------------------------------------------------------------
+    // Initialize memory.
+    //--------------------------------------------------------------------------
     if (!memory_.is_null()) {
       instance->set_memory_buffer(*memory_);
       Address mem_start = static_cast<Address>(memory_->backing_store());
       uint32_t mem_size =
           static_cast<uint32_t>(memory_->byte_length()->Number());
-      LoadDataSegments(mem_start, mem_size);
+      if (!LoadDataSegments(mem_start, mem_size)) return nothing;
 
       uint32_t old_mem_size = compiled_module_->mem_size();
       Address old_mem_start =
@@ -1117,11 +1353,10 @@ class WasmInstanceBuilder {
               ? static_cast<Address>(
                     compiled_module_->memory()->backing_store())
               : nullptr;
-      RelocateMemoryReferencesInCode(code_table, old_mem_start, mem_start,
-                                     old_mem_size, mem_size);
+      RelocateMemoryReferencesInCode(
+          code_table, module_->num_imported_functions, old_mem_start, mem_start,
+          old_mem_size, mem_size);
       compiled_module_->set_memory(memory_);
-    } else {
-      LoadDataSegments(nullptr, 0);
     }
 
     //--------------------------------------------------------------------------
@@ -1144,21 +1379,61 @@ class WasmInstanceBuilder {
     //--------------------------------------------------------------------------
     // Set up the exports object for the new instance.
     //--------------------------------------------------------------------------
-    ProcessExports(code_table, instance);
+    ProcessExports(code_table, instance, compiled_module_);
 
     //--------------------------------------------------------------------------
-    // Set up the indirect function tables for the new instance.
+    // Add instance to Memory object
     //--------------------------------------------------------------------------
-    if (function_table_count > 0) InitializeTables(code_table, instance);
-
-    if (num_imported_functions > 0 || !owner.is_null()) {
-      // If the code was cloned, or new imports were compiled, patch.
-      PatchDirectCalls(old_code_table, code_table, num_imported_functions);
+    DCHECK(wasm::IsWasmInstance(*instance));
+    if (instance->has_memory_object()) {
+      instance->memory_object()->AddInstance(isolate_, instance);
     }
 
+    //--------------------------------------------------------------------------
+    // Initialize the indirect function tables.
+    //--------------------------------------------------------------------------
+    if (function_table_count > 0) LoadTableSegments(code_table, instance);
+
+    // Patch new call sites and the context.
+    PatchDirectCallsAndContext(code_table, compiled_module_, module_,
+                               num_imported_functions);
+
     FlushICache(isolate_, code_table);
 
     //--------------------------------------------------------------------------
+    // Unpack and notify signal handler of protected instructions.
+    //--------------------------------------------------------------------------
+    {
+      for (int i = 0; i < code_table->length(); ++i) {
+        Handle<Code> code = code_table->GetValueChecked<Code>(isolate_, i);
+
+        if (code->kind() != Code::WASM_FUNCTION) {
+          continue;
+        }
+
+        FixedArray* protected_instructions = code->protected_instructions();
+        DCHECK(protected_instructions != nullptr);
+        Zone zone(isolate_->allocator(), "Wasm Module");
+        ZoneVector<trap_handler::ProtectedInstructionData> unpacked(&zone);
+        for (int i = 0; i < protected_instructions->length();
+             i += Code::kTrapDataSize) {
+          trap_handler::ProtectedInstructionData data;
+          data.instr_offset =
+              protected_instructions
+                  ->GetValueChecked<Smi>(isolate_, i + Code::kTrapCodeOffset)
+                  ->value();
+          data.landing_offset =
+              protected_instructions
+                  ->GetValueChecked<Smi>(isolate_, i + Code::kTrapLandingOffset)
+                  ->value();
+          unpacked.emplace_back(data);
+        }
+        // TODO(eholk): Register the protected instruction information once the
+        // trap handler is in place.
+      }
+    }
+
+    //--------------------------------------------------------------------------
     // Set up and link the new instance.
     //--------------------------------------------------------------------------
     {
@@ -1174,7 +1449,7 @@ class WasmInstanceBuilder {
         // we want all the publishing to happen free from GC interruptions, and
         // so we do it in
         // one GC-free scope afterwards.
-        original = handle(owner.ToHandleChecked()->get_compiled_module());
+        original = handle(owner.ToHandleChecked()->compiled_module());
         link_to_original = factory->NewWeakCell(original.ToHandleChecked());
       }
       // Publish the new instance to the instances chain.
@@ -1194,30 +1469,20 @@ class WasmInstanceBuilder {
                                 v8::WeakCallbackType::kFinalizer);
       }
     }
-
-    DCHECK(wasm::IsWasmInstance(*instance));
-    if (instance->has_memory_object()) {
-      instance->get_memory_object()->AddInstance(*instance);
-    }
-
     //--------------------------------------------------------------------------
     // Run the start function if one was specified.
     //--------------------------------------------------------------------------
     if (module_->start_function_index >= 0) {
       HandleScope scope(isolate_);
-      ModuleEnv module_env;
-      module_env.module = module_;
-      module_env.instance = nullptr;
-      module_env.origin = module_->origin;
       int start_index = module_->start_function_index;
       Handle<Code> startup_code =
           code_table->GetValueChecked<Code>(isolate_, start_index);
       FunctionSig* sig = module_->functions[start_index].sig;
       Handle<Code> wrapper_code = compiler::CompileJSToWasmWrapper(
-          isolate_, &module_env, startup_code, start_index);
+          isolate_, module_, startup_code, start_index);
       Handle<WasmExportedFunction> startup_fct = WasmExportedFunction::New(
-          isolate_, instance, factory->InternalizeUtf8String("start"),
-          wrapper_code, static_cast<int>(sig->parameter_count()), start_index);
+          isolate_, instance, MaybeHandle<String>(), start_index,
+          static_cast<int>(sig->parameter_count()), wrapper_code);
       RecordStats(isolate_, *startup_code);
       // Call the JS function.
       Handle<Object> undefined = factory->undefined_value();
@@ -1237,7 +1502,7 @@ class WasmInstanceBuilder {
 
     DCHECK(!isolate_->has_pending_exception());
     TRACE("Finishing instance %d\n", compiled_module_->instance_id());
-    TRACE_CHAIN(WasmCompiledModule::cast(module_object_->GetInternalField(0)));
+    TRACE_CHAIN(module_object_->compiled_module());
     return instance;
   }
 
@@ -1246,13 +1511,14 @@ class WasmInstanceBuilder {
   struct TableInstance {
     Handle<WasmTableObject> table_object;    // WebAssembly.Table instance
     Handle<FixedArray> js_wrappers;          // JSFunctions exported
-    Handle<FixedArray> dispatch_table;       // internal (code, sig) pairs
+    Handle<FixedArray> function_table;       // internal code array
+    Handle<FixedArray> signature_table;      // internal sig array
   };
 
   Isolate* isolate_;
-  WasmModule* module_;
+  WasmModule* const module_;
   ErrorThrower* thrower_;
-  Handle<JSObject> module_object_;
+  Handle<WasmModuleObject> module_object_;
   Handle<JSReceiver> ffi_;
   Handle<JSArrayBuffer> memory_;
   Handle<JSArrayBuffer> globals_;
@@ -1260,58 +1526,49 @@ class WasmInstanceBuilder {
   std::vector<TableInstance> table_instances_;
   std::vector<Handle<JSFunction>> js_wrappers_;
 
-  // Helper routine to print out errors with imports (FFI).
-  MaybeHandle<JSFunction> ReportFFIError(const char* error, uint32_t index,
-                                         Handle<String> module_name,
-                                         MaybeHandle<String> function_name) {
-    Handle<String> function_name_handle;
-    if (function_name.ToHandle(&function_name_handle)) {
-      thrower_->TypeError(
-          "Import #%d module=\"%.*s\" function=\"%.*s\" error: %s", index,
-          module_name->length(), module_name->ToCString().get(),
-          function_name_handle->length(),
-          function_name_handle->ToCString().get(), error);
-    } else {
-      thrower_->TypeError("Import #%d module=\"%.*s\" error: %s", index,
-                          module_name->length(), module_name->ToCString().get(),
-                          error);
-    }
-    thrower_->TypeError("Import ");
-    return MaybeHandle<JSFunction>();
+  // Helper routines to print out errors with imports.
+  void ReportLinkError(const char* error, uint32_t index,
+                       Handle<String> module_name, Handle<String> import_name) {
+    thrower_->LinkError(
+        "Import #%d module=\"%.*s\" function=\"%.*s\" error: %s", index,
+        module_name->length(), module_name->ToCString().get(),
+        import_name->length(), import_name->ToCString().get(), error);
+  }
+
+  MaybeHandle<Object> ReportLinkError(const char* error, uint32_t index,
+                                      Handle<String> module_name) {
+    thrower_->LinkError("Import #%d module=\"%.*s\" error: %s", index,
+                        module_name->length(), module_name->ToCString().get(),
+                        error);
+    return MaybeHandle<Object>();
   }
 
   // Look up an import value in the {ffi_} object.
   MaybeHandle<Object> LookupImport(uint32_t index, Handle<String> module_name,
-                                   MaybeHandle<String> import_name) {
-    if (ffi_.is_null()) {
-      return ReportFFIError("FFI is not an object", index, module_name,
-                            import_name);
-    }
+                                   Handle<String> import_name) {
+    // We pre-validated in the js-api layer that the ffi object is present, and
+    // a JSObject, if the module has imports.
+    DCHECK(!ffi_.is_null());
 
     // Look up the module first.
-    MaybeHandle<Object> result = Object::GetProperty(ffi_, module_name);
+    MaybeHandle<Object> result =
+        Object::GetPropertyOrElement(ffi_, module_name);
     if (result.is_null()) {
-      return ReportFFIError("module not found", index, module_name,
-                            import_name);
+      return ReportLinkError("module not found", index, module_name);
     }
 
     Handle<Object> module = result.ToHandleChecked();
 
-    if (!import_name.is_null()) {
-      // Look up the value in the module.
-      if (!module->IsJSReceiver()) {
-        return ReportFFIError("module is not an object or function", index,
-                              module_name, import_name);
-      }
+    // Look up the value in the module.
+    if (!module->IsJSReceiver()) {
+      return ReportLinkError("module is not an object or function", index,
+                             module_name);
+    }
 
-      result = Object::GetProperty(module, import_name.ToHandleChecked());
-      if (result.is_null()) {
-        return ReportFFIError("import not found", index, module_name,
-                              import_name);
-      }
-    } else {
-      // No function specified. Use the "default export".
-      result = module;
+    result = Object::GetPropertyOrElement(module, import_name);
+    if (result.is_null()) {
+      ReportLinkError("import not found", index, module_name, import_name);
+      return MaybeHandle<JSFunction>();
     }
 
     return result;
@@ -1331,26 +1588,27 @@ class WasmInstanceBuilder {
     }
   }
 
+  bool in_bounds(uint32_t offset, uint32_t size, uint32_t upper) {
+    return offset + size <= upper && offset + size >= offset;
+  }
+
   // Load data segments into the memory.
-  void LoadDataSegments(Address mem_addr, size_t mem_size) {
-    Handle<SeqOneByteString> module_bytes = compiled_module_->module_bytes();
+  bool LoadDataSegments(Address mem_addr, size_t mem_size) {
+    Handle<SeqOneByteString> module_bytes(compiled_module_->module_bytes(),
+                                          isolate_);
     for (const WasmDataSegment& segment : module_->data_segments) {
       uint32_t source_size = segment.source_size;
       // Segments of size == 0 are just nops.
       if (source_size == 0) continue;
       uint32_t dest_offset = EvalUint32InitExpr(segment.dest_addr);
-      if (dest_offset >= mem_size || source_size >= mem_size ||
-          dest_offset > (mem_size - source_size)) {
-        thrower_->TypeError("data segment (start = %" PRIu32 ", size = %" PRIu32
-                            ") does not fit into memory (size = %" PRIuS ")",
-                            dest_offset, source_size, mem_size);
-        return;
-      }
+      DCHECK(in_bounds(dest_offset, source_size,
+                       static_cast<uint32_t>(mem_size)));
       byte* dest = mem_addr + dest_offset;
       const byte* src = reinterpret_cast<const byte*>(
           module_bytes->GetCharsAddress() + segment.source_offset);
       memcpy(dest, src, source_size);
     }
+    return true;
   }
 
   void WriteGlobalValue(WasmGlobal& global, Handle<Object> value) {
@@ -1365,17 +1623,17 @@ class WasmInstanceBuilder {
     TRACE("init [globals+%u] = %lf, type = %s\n", global.offset, num,
           WasmOpcodes::TypeName(global.type));
     switch (global.type) {
-      case kAstI32:
+      case kWasmI32:
         *GetRawGlobalPtr<int32_t>(global) = static_cast<int32_t>(num);
         break;
-      case kAstI64:
+      case kWasmI64:
         // TODO(titzer): initialization of imported i64 globals.
         UNREACHABLE();
         break;
-      case kAstF32:
+      case kWasmF32:
         *GetRawGlobalPtr<float>(global) = static_cast<float>(num);
         break;
-      case kAstF64:
+      case kWasmF64:
         *GetRawGlobalPtr<double>(global) = static_cast<double>(num);
         break;
       default:
@@ -1393,39 +1651,43 @@ class WasmInstanceBuilder {
     for (int index = 0; index < static_cast<int>(module_->import_table.size());
          ++index) {
       WasmImport& import = module_->import_table[index];
-      Handle<String> module_name =
-          ExtractStringFromModuleBytes(isolate_, compiled_module_,
-                                       import.module_name_offset,
-                                       import.module_name_length)
-              .ToHandleChecked();
-      Handle<String> function_name = Handle<String>::null();
-      if (import.field_name_length > 0) {
-        function_name = ExtractStringFromModuleBytes(isolate_, compiled_module_,
-                                                     import.field_name_offset,
-                                                     import.field_name_length)
-                            .ToHandleChecked();
-      }
+
+      Handle<String> module_name;
+      MaybeHandle<String> maybe_module_name =
+          WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+              isolate_, compiled_module_, import.module_name_offset,
+              import.module_name_length);
+      if (!maybe_module_name.ToHandle(&module_name)) return -1;
+
+      Handle<String> import_name;
+      MaybeHandle<String> maybe_import_name =
+          WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+              isolate_, compiled_module_, import.field_name_offset,
+              import.field_name_length);
+      if (!maybe_import_name.ToHandle(&import_name)) return -1;
 
       MaybeHandle<Object> result =
-          LookupImport(index, module_name, function_name);
+          LookupImport(index, module_name, import_name);
       if (thrower_->error()) return -1;
+      Handle<Object> value = result.ToHandleChecked();
 
       switch (import.kind) {
         case kExternalFunction: {
           // Function imports must be callable.
-          Handle<Object> function = result.ToHandleChecked();
-          if (!function->IsCallable()) {
-            ReportFFIError("function import requires a callable", index,
-                           module_name, function_name);
+          if (!value->IsCallable()) {
+            ReportLinkError("function import requires a callable", index,
+                            module_name, import_name);
             return -1;
           }
 
           Handle<Code> import_wrapper = CompileImportWrapper(
               isolate_, index, module_->functions[import.index].sig,
-              Handle<JSReceiver>::cast(function), module_name, function_name);
+              Handle<JSReceiver>::cast(value), module_name, import_name,
+              module_->origin);
           if (import_wrapper.is_null()) {
-            ReportFFIError("imported function does not match the expected type",
-                           index, module_name, function_name);
+            ReportLinkError(
+                "imported function does not match the expected type", index,
+                module_name, import_name);
             return -1;
           }
           code_table->set(num_imported_functions, *import_wrapper);
@@ -1434,10 +1696,9 @@ class WasmInstanceBuilder {
           break;
         }
         case kExternalTable: {
-          Handle<Object> value = result.ToHandleChecked();
           if (!WasmJs::IsWasmTableObject(isolate_, value)) {
-            ReportFFIError("table import requires a WebAssembly.Table", index,
-                           module_name, function_name);
+            ReportLinkError("table import requires a WebAssembly.Table", index,
+                            module_name, import_name);
             return -1;
           }
           WasmIndirectFunctionTable& table =
@@ -1445,23 +1706,43 @@ class WasmInstanceBuilder {
           TableInstance& table_instance = table_instances_[num_imported_tables];
           table_instance.table_object = Handle<WasmTableObject>::cast(value);
           table_instance.js_wrappers = Handle<FixedArray>(
-              table_instance.table_object->get_functions(), isolate_);
-
-          // TODO(titzer): import table size must match exactly for now.
-          int table_size = table_instance.js_wrappers->length();
-          if (table_size != static_cast<int>(table.min_size)) {
-            thrower_->TypeError(
-                "table import %d is wrong size (%d), expected %u", index,
-                table_size, table.min_size);
+              table_instance.table_object->functions(), isolate_);
+
+          int imported_cur_size = table_instance.js_wrappers->length();
+          if (imported_cur_size < static_cast<int>(table.min_size)) {
+            thrower_->LinkError(
+                "table import %d is smaller than minimum %d, got %u", index,
+                table.min_size, imported_cur_size);
             return -1;
           }
 
-          // Allocate a new dispatch table.
-          table_instance.dispatch_table =
-              isolate_->factory()->NewFixedArray(table_size * 2);
-          for (int i = 0; i < table_size * 2; ++i) {
-            table_instance.dispatch_table->set(i,
-                                               Smi::FromInt(kInvalidSigIndex));
+          if (table.has_max) {
+            int64_t imported_max_size =
+                table_instance.table_object->maximum_length();
+            if (imported_max_size < 0) {
+              thrower_->LinkError(
+                  "table import %d has no maximum length, expected %d", index,
+                  table.max_size);
+              return -1;
+            }
+            if (imported_max_size > table.max_size) {
+              thrower_->LinkError(
+                  "table import %d has maximum larger than maximum %d, "
+                  "got %" PRIx64,
+                  index, table.max_size, imported_max_size);
+              return -1;
+            }
+          }
+
+          // Allocate a new dispatch table and signature table.
+          int table_size = imported_cur_size;
+          table_instance.function_table =
+              isolate_->factory()->NewFixedArray(table_size);
+          table_instance.signature_table =
+              isolate_->factory()->NewFixedArray(table_size);
+          for (int i = 0; i < table_size; ++i) {
+            table_instance.signature_table->set(i,
+                                                Smi::FromInt(kInvalidSigIndex));
           }
           // Initialize the dispatch table with the (foreign) JS functions
           // that are already in the table.
@@ -1471,43 +1752,70 @@ class WasmInstanceBuilder {
             WasmFunction* function =
                 GetWasmFunctionForImportWrapper(isolate_, val);
             if (function == nullptr) {
-              thrower_->TypeError("table import %d[%d] is not a WASM function",
+              thrower_->LinkError("table import %d[%d] is not a WASM function",
                                   index, i);
               return -1;
             }
             int sig_index = table.map.FindOrInsert(function->sig);
-            table_instance.dispatch_table->set(i, Smi::FromInt(sig_index));
-            table_instance.dispatch_table->set(i + table_size,
-                                               *UnwrapImportWrapper(val));
+            table_instance.signature_table->set(i, Smi::FromInt(sig_index));
+            table_instance.function_table->set(i, *UnwrapImportWrapper(val));
           }
 
           num_imported_tables++;
           break;
         }
         case kExternalMemory: {
-          Handle<Object> object = result.ToHandleChecked();
-          if (!WasmJs::IsWasmMemoryObject(isolate_, object)) {
-            ReportFFIError("memory import must be a WebAssembly.Memory object",
-                           index, module_name, function_name);
+          // Validation should have failed if more than one memory object was
+          // provided.
+          DCHECK(!instance->has_memory_object());
+          if (!WasmJs::IsWasmMemoryObject(isolate_, value)) {
+            ReportLinkError("memory import must be a WebAssembly.Memory object",
+                            index, module_name, import_name);
             return -1;
           }
-          auto memory = Handle<WasmMemoryObject>::cast(object);
+          auto memory = Handle<WasmMemoryObject>::cast(value);
+          DCHECK(WasmJs::IsWasmMemoryObject(isolate_, memory));
           instance->set_memory_object(*memory);
-          memory_ = Handle<JSArrayBuffer>(memory->get_buffer(), isolate_);
+          memory_ = Handle<JSArrayBuffer>(memory->buffer(), isolate_);
+          uint32_t imported_cur_pages = static_cast<uint32_t>(
+              memory_->byte_length()->Number() / WasmModule::kPageSize);
+          if (imported_cur_pages < module_->min_mem_pages) {
+            thrower_->LinkError(
+                "memory import %d is smaller than maximum %u, got %u", index,
+                module_->min_mem_pages, imported_cur_pages);
+          }
+          int32_t imported_max_pages = memory->maximum_pages();
+          if (module_->has_max_mem) {
+            if (imported_max_pages < 0) {
+              thrower_->LinkError(
+                  "memory import %d has no maximum limit, expected at most %u",
+                  index, imported_max_pages);
+              return -1;
+            }
+            if (static_cast<uint32_t>(imported_max_pages) >
+                module_->max_mem_pages) {
+              thrower_->LinkError(
+                  "memory import %d has larger maximum than maximum %u, got %d",
+                  index, module_->max_mem_pages, imported_max_pages);
+              return -1;
+            }
+          }
           break;
         }
         case kExternalGlobal: {
           // Global imports are converted to numbers and written into the
           // {globals_} array buffer.
-          Handle<Object> object = result.ToHandleChecked();
-          MaybeHandle<Object> number = Object::ToNumber(object);
-          if (number.is_null()) {
-            ReportFFIError("global import could not be converted to number",
-                           index, module_name, function_name);
+          if (module_->globals[import.index].type == kWasmI64) {
+            ReportLinkError("global import cannot have type i64", index,
+                            module_name, import_name);
+            return -1;
+          }
+          if (!value->IsNumber()) {
+            ReportLinkError("global import must be a number", index,
+                            module_name, import_name);
             return -1;
           }
-          Handle<Object> val = number.ToHandleChecked();
-          WriteGlobalValue(module_->globals[import.index], val);
+          WriteGlobalValue(module_->globals[import.index], value);
           break;
         }
         default:
@@ -1546,7 +1854,7 @@ class WasmInstanceBuilder {
               module_->globals[global.init.val.global_index].offset;
           TRACE("init [globals+%u] = [globals+%d]\n", global.offset,
                 old_offset);
-          size_t size = (global.type == kAstI64 || global.type == kAstF64)
+          size_t size = (global.type == kWasmI64 || global.type == kWasmF64)
                             ? sizeof(double)
                             : sizeof(int32_t);
           memcpy(raw_buffer_ptr(globals_, new_offset),
@@ -1565,12 +1873,13 @@ class WasmInstanceBuilder {
 
   // Allocate memory for a module instance as a new JSArrayBuffer.
   Handle<JSArrayBuffer> AllocateMemory(uint32_t min_mem_pages) {
-    if (min_mem_pages > WasmModule::kV8MaxPages) {
+    if (min_mem_pages > kV8MaxWasmMemoryPages) {
       thrower_->RangeError("Out of memory: wasm memory too large");
       return Handle<JSArrayBuffer>::null();
     }
-    Handle<JSArrayBuffer> mem_buffer =
-        NewArrayBuffer(isolate_, min_mem_pages * WasmModule::kPageSize);
+    const bool enable_guard_regions = EnableGuardRegions();
+    Handle<JSArrayBuffer> mem_buffer = NewArrayBuffer(
+        isolate_, min_mem_pages * WasmModule::kPageSize, enable_guard_regions);
 
     if (mem_buffer.is_null()) {
       thrower_->RangeError("Out of memory: wasm memory");
@@ -1578,31 +1887,30 @@ class WasmInstanceBuilder {
     return mem_buffer;
   }
 
-  // Process the exports, creating wrappers for functions, tables, memories,
-  // and globals.
-  void ProcessExports(Handle<FixedArray> code_table,
-                      Handle<WasmInstanceObject> instance) {
-    bool needs_wrappers = module_->num_exported_functions > 0;
+  bool NeedsWrappers() {
+    if (module_->num_exported_functions > 0) return true;
     for (auto table_instance : table_instances_) {
-      if (!table_instance.js_wrappers.is_null()) {
-        needs_wrappers = true;
-        break;
-      }
+      if (!table_instance.js_wrappers.is_null()) return true;
     }
     for (auto table : module_->function_tables) {
-      if (table.exported) {
-        needs_wrappers = true;
-        break;
-      }
+      if (table.exported) return true;
     }
-    if (needs_wrappers) {
+    return false;
+  }
+
+  // Process the exports, creating wrappers for functions, tables, memories,
+  // and globals.
+  void ProcessExports(Handle<FixedArray> code_table,
+                      Handle<WasmInstanceObject> instance,
+                      Handle<WasmCompiledModule> compiled_module) {
+    if (NeedsWrappers()) {
       // Fill the table to cache the exported JSFunction wrappers.
       js_wrappers_.insert(js_wrappers_.begin(), module_->functions.size(),
                           Handle<JSFunction>::null());
     }
 
     Handle<JSObject> exports_object = instance;
-    if (module_->export_table.size() > 0 && module_->origin == kWasmOrigin) {
+    if (module_->origin == kWasmOrigin) {
       // Create the "exports" object.
       Handle<JSFunction> object_function = Handle<JSFunction>(
           isolate_->native_context()->object_function(), isolate_);
@@ -1610,38 +1918,68 @@ class WasmInstanceBuilder {
           isolate_->factory()->NewJSObject(object_function, TENURED);
       Handle<String> exports_name =
           isolate_->factory()->InternalizeUtf8String("exports");
-      JSObject::AddProperty(instance, exports_name, exports_object, READ_ONLY);
+      JSObject::AddProperty(instance, exports_name, exports_object, NONE);
     }
 
     PropertyDescriptor desc;
     desc.set_writable(false);
+    desc.set_enumerable(true);
 
-    // Process each export in the export table.
+    // Count up export indexes.
     int export_index = 0;
     for (auto exp : module_->export_table) {
+      if (exp.kind == kExternalFunction) {
+        ++export_index;
+      }
+    }
+
+    // Store weak references to all exported functions.
+    Handle<FixedArray> weak_exported_functions;
+    if (compiled_module->has_weak_exported_functions()) {
+      weak_exported_functions = compiled_module->weak_exported_functions();
+    } else {
+      weak_exported_functions =
+          isolate_->factory()->NewFixedArray(export_index);
+      compiled_module->set_weak_exported_functions(weak_exported_functions);
+    }
+    DCHECK_EQ(export_index, weak_exported_functions->length());
+
+    // Process each export in the export table (go in reverse so asm.js
+    // can skip duplicates).
+    for (auto exp : base::Reversed(module_->export_table)) {
       Handle<String> name =
-          ExtractStringFromModuleBytes(isolate_, compiled_module_,
-                                       exp.name_offset, exp.name_length)
+          WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+              isolate_, compiled_module_, exp.name_offset, exp.name_length)
               .ToHandleChecked();
       switch (exp.kind) {
         case kExternalFunction: {
           // Wrap and export the code as a JSFunction.
           WasmFunction& function = module_->functions[exp.index];
           int func_index =
-              static_cast<int>(module_->functions.size() + export_index);
+              static_cast<int>(module_->functions.size() + --export_index);
           Handle<JSFunction> js_function = js_wrappers_[exp.index];
           if (js_function.is_null()) {
             // Wrap the exported code as a JSFunction.
             Handle<Code> export_code =
                 code_table->GetValueChecked<Code>(isolate_, func_index);
+            MaybeHandle<String> func_name;
+            if (module_->origin == kAsmJsOrigin) {
+              // For modules arising from asm.js, honor the names section.
+              func_name = WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+                              isolate_, compiled_module_, function.name_offset,
+                              function.name_length)
+                              .ToHandleChecked();
+            }
             js_function = WasmExportedFunction::New(
-                isolate_, instance, name, export_code,
-                static_cast<int>(function.sig->parameter_count()),
-                function.func_index);
+                isolate_, instance, func_name, function.func_index,
+                static_cast<int>(function.sig->parameter_count()), export_code);
             js_wrappers_[exp.index] = js_function;
           }
           desc.set_value(js_function);
-          export_index++;
+          Handle<WeakCell> weak_export =
+              isolate_->factory()->NewWeakCell(js_function);
+          DCHECK_GT(weak_exported_functions->length(), export_index);
+          weak_exported_functions->set(export_index, *weak_export);
           break;
         }
         case kExternalTable: {
@@ -1651,7 +1989,7 @@ class WasmInstanceBuilder {
               module_->function_tables[exp.index];
           if (table_instance.table_object.is_null()) {
             uint32_t maximum =
-                table.has_max ? table.max_size : WasmModule::kV8MaxTableSize;
+                table.has_max ? table.max_size : kV8MaxWasmTableSize;
             table_instance.table_object = WasmTableObject::New(
                 isolate_, table.min_size, maximum, &table_instance.js_wrappers);
           }
@@ -1663,15 +2001,16 @@ class WasmInstanceBuilder {
           Handle<WasmMemoryObject> memory_object;
           if (!instance->has_memory_object()) {
             // If there was no imported WebAssembly.Memory object, create one.
-            Handle<JSArrayBuffer> buffer(instance->get_memory_buffer(),
-                                         isolate_);
+            Handle<JSArrayBuffer> buffer(instance->memory_buffer(), isolate_);
             memory_object = WasmMemoryObject::New(
                 isolate_, buffer,
                 (module_->max_mem_pages != 0) ? module_->max_mem_pages : -1);
             instance->set_memory_object(*memory_object);
           } else {
-            memory_object = Handle<WasmMemoryObject>(
-                instance->get_memory_object(), isolate_);
+            memory_object =
+                Handle<WasmMemoryObject>(instance->memory_object(), isolate_);
+            DCHECK(WasmJs::IsWasmMemoryObject(isolate_, memory_object));
+            memory_object->ResetInstancesLink(isolate_);
           }
 
           desc.set_value(memory_object);
@@ -1682,15 +2021,19 @@ class WasmInstanceBuilder {
           WasmGlobal& global = module_->globals[exp.index];
           double num = 0;
           switch (global.type) {
-            case kAstI32:
+            case kWasmI32:
               num = *GetRawGlobalPtr<int32_t>(global);
               break;
-            case kAstF32:
+            case kWasmF32:
               num = *GetRawGlobalPtr<float>(global);
               break;
-            case kAstF64:
+            case kWasmF64:
               num = *GetRawGlobalPtr<double>(global);
               break;
+            case kWasmI64:
+              thrower_->LinkError(
+                  "export of globals of type I64 is not allowed.");
+              break;
             default:
               UNREACHABLE();
           }
@@ -1702,42 +2045,99 @@ class WasmInstanceBuilder {
           break;
       }
 
+      // Skip duplicates for asm.js.
+      if (module_->origin == kAsmJsOrigin) {
+        v8::Maybe<bool> status =
+            JSReceiver::HasOwnProperty(exports_object, name);
+        if (status.FromMaybe(false)) {
+          continue;
+        }
+      }
       v8::Maybe<bool> status = JSReceiver::DefineOwnProperty(
           isolate_, exports_object, name, &desc, Object::THROW_ON_ERROR);
       if (!status.IsJust()) {
-        thrower_->TypeError("export of %.*s failed.", name->length(),
+        thrower_->LinkError("export of %.*s failed.", name->length(),
                             name->ToCString().get());
         return;
       }
     }
+
+    if (module_->origin == kWasmOrigin) {
+      v8::Maybe<bool> success = JSReceiver::SetIntegrityLevel(
+          exports_object, FROZEN, Object::DONT_THROW);
+      DCHECK(success.FromMaybe(false));
+      USE(success);
+    }
   }
 
   void InitializeTables(Handle<FixedArray> code_table,
                         Handle<WasmInstanceObject> instance) {
-    Handle<FixedArray> old_function_tables =
-        compiled_module_->function_tables();
     int function_table_count =
         static_cast<int>(module_->function_tables.size());
     Handle<FixedArray> new_function_tables =
         isolate_->factory()->NewFixedArray(function_table_count);
+    Handle<FixedArray> new_signature_tables =
+        isolate_->factory()->NewFixedArray(function_table_count);
     for (int index = 0; index < function_table_count; ++index) {
       WasmIndirectFunctionTable& table = module_->function_tables[index];
       TableInstance& table_instance = table_instances_[index];
       int table_size = static_cast<int>(table.min_size);
 
-      if (table_instance.dispatch_table.is_null()) {
+      if (table_instance.function_table.is_null()) {
         // Create a new dispatch table if necessary.
-        table_instance.dispatch_table =
-            isolate_->factory()->NewFixedArray(table_size * 2);
+        table_instance.function_table =
+            isolate_->factory()->NewFixedArray(table_size);
+        table_instance.signature_table =
+            isolate_->factory()->NewFixedArray(table_size);
         for (int i = 0; i < table_size; ++i) {
           // Fill the table with invalid signature indexes so that
           // uninitialized entries will always fail the signature check.
-          table_instance.dispatch_table->set(i, Smi::FromInt(kInvalidSigIndex));
+          table_instance.signature_table->set(i,
+                                              Smi::FromInt(kInvalidSigIndex));
+        }
+      } else {
+        // Table is imported, patch table bounds check
+        DCHECK(table_size <= table_instance.function_table->length());
+        if (table_size < table_instance.function_table->length()) {
+          RelocateTableSizeReferences(code_table, table_size,
+                                      table_instance.function_table->length());
         }
       }
 
       new_function_tables->set(static_cast<int>(index),
-                               *table_instance.dispatch_table);
+                               *table_instance.function_table);
+      new_signature_tables->set(static_cast<int>(index),
+                                *table_instance.signature_table);
+    }
+
+    // Patch all code that has references to the old indirect tables.
+    Handle<FixedArray> old_function_tables =
+        compiled_module_->function_tables();
+    Handle<FixedArray> old_signature_tables =
+        compiled_module_->signature_tables();
+    for (int i = 0; i < code_table->length(); ++i) {
+      if (!code_table->get(i)->IsCode()) continue;
+      Handle<Code> code(Code::cast(code_table->get(i)), isolate_);
+      for (int j = 0; j < function_table_count; ++j) {
+        ReplaceReferenceInCode(
+            code, Handle<Object>(old_function_tables->get(j), isolate_),
+            Handle<Object>(new_function_tables->get(j), isolate_));
+        ReplaceReferenceInCode(
+            code, Handle<Object>(old_signature_tables->get(j), isolate_),
+            Handle<Object>(new_signature_tables->get(j), isolate_));
+      }
+    }
+    compiled_module_->set_function_tables(new_function_tables);
+    compiled_module_->set_signature_tables(new_signature_tables);
+  }
+
+  void LoadTableSegments(Handle<FixedArray> code_table,
+                         Handle<WasmInstanceObject> instance) {
+    int function_table_count =
+        static_cast<int>(module_->function_tables.size());
+    for (int index = 0; index < function_table_count; ++index) {
+      WasmIndirectFunctionTable& table = module_->function_tables[index];
+      TableInstance& table_instance = table_instances_[index];
 
       Handle<FixedArray> all_dispatch_tables;
       if (!table_instance.table_object.is_null()) {
@@ -1745,28 +2145,24 @@ class WasmInstanceBuilder {
         all_dispatch_tables = WasmTableObject::AddDispatchTable(
             isolate_, table_instance.table_object,
             Handle<WasmInstanceObject>::null(), index,
-            Handle<FixedArray>::null());
+            Handle<FixedArray>::null(), Handle<FixedArray>::null());
       }
 
       // TODO(titzer): this does redundant work if there are multiple tables,
       // since initializations are not sorted by table index.
       for (auto table_init : module_->table_inits) {
         uint32_t base = EvalUint32InitExpr(table_init.offset);
-        if (base > static_cast<uint32_t>(table_size) ||
-            (base + table_init.entries.size() >
-             static_cast<uint32_t>(table_size))) {
-          thrower_->CompileError("table initializer is out of bounds");
-          continue;
-        }
+        DCHECK(in_bounds(base, static_cast<uint32_t>(table_init.entries.size()),
+                         table_instance.function_table->length()));
         for (int i = 0; i < static_cast<int>(table_init.entries.size()); ++i) {
           uint32_t func_index = table_init.entries[i];
           WasmFunction* function = &module_->functions[func_index];
           int table_index = static_cast<int>(i + base);
           int32_t sig_index = table.map.Find(function->sig);
           DCHECK_GE(sig_index, 0);
-          table_instance.dispatch_table->set(table_index,
-                                             Smi::FromInt(sig_index));
-          table_instance.dispatch_table->set(table_index + table_size,
+          table_instance.signature_table->set(table_index,
+                                              Smi::FromInt(sig_index));
+          table_instance.function_table->set(table_index,
                                              code_table->get(func_index));
 
           if (!all_dispatch_tables.is_null()) {
@@ -1783,19 +2179,22 @@ class WasmInstanceBuilder {
               temp_instance.mem_start = nullptr;
               temp_instance.globals_start = nullptr;
 
-              ModuleEnv module_env;
-              module_env.module = module_;
-              module_env.instance = &temp_instance;
-              module_env.origin = module_->origin;
-
               Handle<Code> wrapper_code = compiler::CompileJSToWasmWrapper(
-                  isolate_, &module_env, wasm_code, func_index);
+                  isolate_, module_, wasm_code, func_index);
+              MaybeHandle<String> func_name;
+              if (module_->origin == kAsmJsOrigin) {
+                // For modules arising from asm.js, honor the names section.
+                func_name =
+                    WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+                        isolate_, compiled_module_, function->name_offset,
+                        function->name_length)
+                        .ToHandleChecked();
+              }
               Handle<WasmExportedFunction> js_function =
                   WasmExportedFunction::New(
-                      isolate_, instance, isolate_->factory()->empty_string(),
-                      wrapper_code,
+                      isolate_, instance, func_name, func_index,
                       static_cast<int>(function->sig->parameter_count()),
-                      func_index);
+                      wrapper_code);
               js_wrappers_[func_index] = js_function;
             }
             table_instance.js_wrappers->set(table_index,
@@ -1814,115 +2213,57 @@ class WasmInstanceBuilder {
         // Add the new dispatch table to the WebAssembly.Table object.
         all_dispatch_tables = WasmTableObject::AddDispatchTable(
             isolate_, table_instance.table_object, instance, index,
-            table_instance.dispatch_table);
+            table_instance.function_table, table_instance.signature_table);
       }
     }
-    // Patch all code that has references to the old indirect tables.
-    for (int i = 0; i < code_table->length(); ++i) {
-      if (!code_table->get(i)->IsCode()) continue;
-      Handle<Code> code(Code::cast(code_table->get(i)), isolate_);
-      for (int j = 0; j < function_table_count; ++j) {
-        ReplaceReferenceInCode(
-            code, Handle<Object>(old_function_tables->get(j), isolate_),
-            Handle<Object>(new_function_tables->get(j), isolate_));
-      }
-    }
-    compiled_module_->set_function_tables(new_function_tables);
   }
 };
 
 // Instantiates a WASM module, creating a WebAssembly.Instance from a
 // WebAssembly.Module.
-MaybeHandle<JSObject> WasmModule::Instantiate(Isolate* isolate,
-                                              ErrorThrower* thrower,
-                                              Handle<JSObject> wasm_module,
-                                              Handle<JSReceiver> ffi,
-                                              Handle<JSArrayBuffer> memory) {
+MaybeHandle<WasmInstanceObject> WasmModule::Instantiate(
+    Isolate* isolate, ErrorThrower* thrower,
+    Handle<WasmModuleObject> wasm_module, Handle<JSReceiver> ffi,
+    Handle<JSArrayBuffer> memory) {
   WasmInstanceBuilder builder(isolate, thrower, wasm_module, ffi, memory);
   return builder.Build();
 }
 
-Handle<String> wasm::GetWasmFunctionName(Isolate* isolate,
-                                         Handle<Object> instance_or_undef,
-                                         uint32_t func_index) {
-  if (!instance_or_undef->IsUndefined(isolate)) {
-    Handle<WasmCompiledModule> compiled_module(
-        Handle<WasmInstanceObject>::cast(instance_or_undef)
-            ->get_compiled_module());
-    MaybeHandle<String> maybe_name =
-        WasmCompiledModule::GetFunctionName(compiled_module, func_index);
-    if (!maybe_name.is_null()) return maybe_name.ToHandleChecked();
-  }
-  return isolate->factory()->NewStringFromStaticChars("<WASM UNNAMED>");
-}
-
 bool wasm::IsWasmInstance(Object* object) {
   return WasmInstanceObject::IsWasmInstanceObject(object);
 }
 
-WasmCompiledModule* wasm::GetCompiledModule(Object* object) {
-  return WasmInstanceObject::cast(object)->get_compiled_module();
-}
-
-bool wasm::WasmIsAsmJs(Object* instance, Isolate* isolate) {
-  if (instance->IsUndefined(isolate)) return false;
-  DCHECK(IsWasmInstance(instance));
-  WasmCompiledModule* compiled_module =
-      GetCompiledModule(JSObject::cast(instance));
-  DCHECK_EQ(compiled_module->has_asm_js_offset_tables(),
-            compiled_module->script()->type() == Script::TYPE_NORMAL);
-  return compiled_module->has_asm_js_offset_tables();
-}
-
 Handle<Script> wasm::GetScript(Handle<JSObject> instance) {
-  DCHECK(IsWasmInstance(*instance));
-  WasmCompiledModule* compiled_module = GetCompiledModule(*instance);
-  DCHECK(compiled_module->has_script());
-  return compiled_module->script();
-}
-
-int wasm::GetAsmWasmSourcePosition(Handle<JSObject> instance, int func_index,
-                                   int byte_offset) {
-  return WasmDebugInfo::GetAsmJsSourcePosition(GetDebugInfo(instance),
-                                               func_index, byte_offset);
-}
-
-Handle<SeqOneByteString> wasm::GetWasmBytes(Handle<JSObject> object) {
-  return Handle<WasmInstanceObject>::cast(object)
-      ->get_compiled_module()
-      ->module_bytes();
-}
-
-Handle<WasmDebugInfo> wasm::GetDebugInfo(Handle<JSObject> object) {
-  auto instance = Handle<WasmInstanceObject>::cast(object);
-  if (instance->has_debug_info()) {
-    Handle<WasmDebugInfo> info(instance->get_debug_info(),
-                               instance->GetIsolate());
-    return info;
-  }
-  Handle<WasmDebugInfo> new_info = WasmDebugInfo::New(instance);
-  instance->set_debug_info(*new_info);
-  return new_info;
+  WasmCompiledModule* compiled_module =
+      WasmInstanceObject::cast(*instance)->compiled_module();
+  return handle(compiled_module->script());
 }
 
-int wasm::GetNumberOfFunctions(Handle<JSObject> object) {
-  return static_cast<int>(
-      Handle<WasmInstanceObject>::cast(object)->module()->functions.size());
+bool wasm::IsWasmCodegenAllowed(Isolate* isolate, Handle<Context> context) {
+  return isolate->allow_code_gen_callback() == nullptr ||
+         isolate->allow_code_gen_callback()(v8::Utils::ToLocal(context));
 }
 
 // TODO(clemensh): origin can be inferred from asm_js_script; remove it.
 MaybeHandle<WasmModuleObject> wasm::CreateModuleObjectFromBytes(
     Isolate* isolate, const byte* start, const byte* end, ErrorThrower* thrower,
     ModuleOrigin origin, Handle<Script> asm_js_script,
-    const byte* asm_js_offset_tables_start,
-    const byte* asm_js_offset_tables_end) {
+    Vector<const byte> asm_js_offset_table_bytes) {
   MaybeHandle<WasmModuleObject> nothing;
+
+  if (origin != kAsmJsOrigin &&
+      !IsWasmCodegenAllowed(isolate, isolate->native_context())) {
+    thrower->CompileError("Wasm code generation disallowed in this context");
+    return nothing;
+  }
+
   ModuleResult result = DecodeWasmModule(isolate, start, end, false, origin);
   if (result.failed()) {
     if (result.val) delete result.val;
     thrower->CompileFailed("Wasm decoding failed", result);
     return nothing;
   }
+
   // The {module_wrapper} will take ownership of the {WasmModule} object,
   // and it will be destroyed when the GC reclaims the wrapper object.
   Handle<WasmModuleWrapper> module_wrapper =
@@ -1930,61 +2271,15 @@ MaybeHandle<WasmModuleObject> wasm::CreateModuleObjectFromBytes(
 
   // Compile the functions of the module, producing a compiled module.
   MaybeHandle<WasmCompiledModule> maybe_compiled_module =
-      result.val->CompileFunctions(isolate, module_wrapper, thrower);
+      result.val->CompileFunctions(isolate, module_wrapper, thrower,
+                                   ModuleWireBytes(start, end), asm_js_script,
+                                   asm_js_offset_table_bytes);
 
   if (maybe_compiled_module.is_null()) return nothing;
 
   Handle<WasmCompiledModule> compiled_module =
       maybe_compiled_module.ToHandleChecked();
 
-  DCHECK_EQ(origin == kAsmJsOrigin, !asm_js_script.is_null());
-  DCHECK(!compiled_module->has_script());
-  DCHECK(!compiled_module->has_asm_js_offset_tables());
-  if (origin == kAsmJsOrigin) {
-    // Set script for the asm.js source, and the offset table mapping wasm byte
-    // offsets to source positions.
-    compiled_module->set_script(asm_js_script);
-    size_t offset_tables_len =
-        asm_js_offset_tables_end - asm_js_offset_tables_start;
-    DCHECK_GE(static_cast<size_t>(kMaxInt), offset_tables_len);
-    Handle<ByteArray> offset_tables =
-        isolate->factory()->NewByteArray(static_cast<int>(offset_tables_len));
-    memcpy(offset_tables->GetDataStartAddress(), asm_js_offset_tables_start,
-           offset_tables_len);
-    compiled_module->set_asm_js_offset_tables(offset_tables);
-  } else {
-    // Create a new Script object representing this wasm module, store it in the
-    // compiled wasm module, and register it at the debugger.
-    Handle<Script> script =
-        isolate->factory()->NewScript(isolate->factory()->empty_string());
-    script->set_type(Script::TYPE_WASM);
-
-    DCHECK_GE(kMaxInt, end - start);
-    int hash = StringHasher::HashSequentialString(
-        reinterpret_cast<const char*>(start), static_cast<int>(end - start),
-        kZeroHashSeed);
-
-    const int kBufferSize = 50;
-    char buffer[kBufferSize];
-    int url_chars = SNPrintF(ArrayVector(buffer), "wasm://wasm/%08x", hash);
-    DCHECK(url_chars >= 0 && url_chars < kBufferSize);
-    MaybeHandle<String> url_str = isolate->factory()->NewStringFromOneByte(
-        Vector<const uint8_t>(reinterpret_cast<uint8_t*>(buffer), url_chars),
-        TENURED);
-    script->set_source_url(*url_str.ToHandleChecked());
-
-    int name_chars = SNPrintF(ArrayVector(buffer), "wasm-%08x", hash);
-    DCHECK(name_chars >= 0 && name_chars < kBufferSize);
-    MaybeHandle<String> name_str = isolate->factory()->NewStringFromOneByte(
-        Vector<const uint8_t>(reinterpret_cast<uint8_t*>(buffer), name_chars),
-        TENURED);
-    script->set_name(*name_str.ToHandleChecked());
-
-    script->set_wasm_compiled_module(*compiled_module);
-    compiled_module->set_script(script);
-    isolate->debug()->OnAfterCompile(script);
-  }
-
   return WasmModuleObject::New(isolate, compiled_module);
 }
 
@@ -2000,24 +2295,25 @@ bool wasm::ValidateModuleBytes(Isolate* isolate, const byte* start,
   return result.ok();
 }
 
-MaybeHandle<JSArrayBuffer> wasm::GetInstanceMemory(Isolate* isolate,
-                                                   Handle<JSObject> object) {
+MaybeHandle<JSArrayBuffer> wasm::GetInstanceMemory(
+    Isolate* isolate, Handle<WasmInstanceObject> object) {
   auto instance = Handle<WasmInstanceObject>::cast(object);
   if (instance->has_memory_buffer()) {
-    return Handle<JSArrayBuffer>(instance->get_memory_buffer(), isolate);
+    return Handle<JSArrayBuffer>(instance->memory_buffer(), isolate);
   }
   return MaybeHandle<JSArrayBuffer>();
 }
 
-void SetInstanceMemory(Handle<JSObject> object, JSArrayBuffer* buffer) {
+void SetInstanceMemory(Handle<WasmInstanceObject> instance,
+                       JSArrayBuffer* buffer) {
   DisallowHeapAllocation no_gc;
-  auto instance = Handle<WasmInstanceObject>::cast(object);
   instance->set_memory_buffer(buffer);
-  instance->get_compiled_module()->set_ptr_to_memory(buffer);
+  instance->compiled_module()->set_ptr_to_memory(buffer);
 }
 
 int32_t wasm::GetInstanceMemorySize(Isolate* isolate,
-                                    Handle<JSObject> instance) {
+                                    Handle<WasmInstanceObject> instance) {
+  DCHECK(IsWasmInstance(*instance));
   MaybeHandle<JSArrayBuffer> maybe_mem_buffer =
       GetInstanceMemory(isolate, instance);
   Handle<JSArrayBuffer> buffer;
@@ -2028,92 +2324,222 @@ int32_t wasm::GetInstanceMemorySize(Isolate* isolate,
   }
 }
 
-uint32_t GetMaxInstanceMemorySize(Isolate* isolate,
-                                  Handle<WasmInstanceObject> instance) {
+uint32_t GetMaxInstanceMemoryPages(Isolate* isolate,
+                                   Handle<WasmInstanceObject> instance) {
   if (instance->has_memory_object()) {
-    Handle<WasmMemoryObject> memory_object(instance->get_memory_object(),
-                                           isolate);
-
-    int maximum = memory_object->maximum_pages();
-    if (maximum > 0) return static_cast<uint32_t>(maximum);
+    Handle<WasmMemoryObject> memory_object(instance->memory_object(), isolate);
+    if (memory_object->has_maximum_pages()) {
+      uint32_t maximum = static_cast<uint32_t>(memory_object->maximum_pages());
+      if (maximum < kV8MaxWasmMemoryPages) return maximum;
+    }
   }
-  uint32_t compiled_max_pages =
-      instance->get_compiled_module()->max_mem_pages();
+  uint32_t compiled_max_pages = instance->compiled_module()->max_mem_pages();
   isolate->counters()->wasm_max_mem_pages_count()->AddSample(
       compiled_max_pages);
   if (compiled_max_pages != 0) return compiled_max_pages;
-  return WasmModule::kV8MaxPages;
+  return kV8MaxWasmMemoryPages;
 }
 
-int32_t wasm::GrowInstanceMemory(Isolate* isolate, Handle<JSObject> object,
-                                 uint32_t pages) {
-  if (!IsWasmInstance(*object)) return -1;
-  auto instance = Handle<WasmInstanceObject>::cast(object);
-  if (pages == 0) return GetInstanceMemorySize(isolate, instance);
-  uint32_t max_pages = GetMaxInstanceMemorySize(isolate, instance);
-
-  Address old_mem_start = nullptr;
-  uint32_t old_size = 0, new_size = 0;
-
-  MaybeHandle<JSArrayBuffer> maybe_mem_buffer =
-      GetInstanceMemory(isolate, instance);
+Handle<JSArrayBuffer> GrowMemoryBuffer(Isolate* isolate,
+                                       MaybeHandle<JSArrayBuffer> buffer,
+                                       uint32_t pages, uint32_t max_pages) {
   Handle<JSArrayBuffer> old_buffer;
-  if (!maybe_mem_buffer.ToHandle(&old_buffer) ||
-      old_buffer->backing_store() == nullptr) {
-    // If module object does not have linear memory associated with it,
-    // Allocate new array buffer of given size.
-    new_size = pages * WasmModule::kPageSize;
-    if (max_pages < pages) return -1;
-  } else {
+  Address old_mem_start = nullptr;
+  uint32_t old_size = 0;
+  if (buffer.ToHandle(&old_buffer) && old_buffer->backing_store() != nullptr) {
     old_mem_start = static_cast<Address>(old_buffer->backing_store());
-    old_size = old_buffer->byte_length()->Number();
-    // If the old memory was zero-sized, we should have been in the
-    // "undefined" case above.
     DCHECK_NOT_NULL(old_mem_start);
-    DCHECK(old_size + pages * WasmModule::kPageSize <=
-           std::numeric_limits<uint32_t>::max());
-    new_size = old_size + pages * WasmModule::kPageSize;
+    old_size = old_buffer->byte_length()->Number();
   }
-
+  DCHECK(old_size + pages * WasmModule::kPageSize <=
+         std::numeric_limits<uint32_t>::max());
+  uint32_t new_size = old_size + pages * WasmModule::kPageSize;
   if (new_size <= old_size || max_pages * WasmModule::kPageSize < new_size ||
-      WasmModule::kV8MaxPages * WasmModule::kPageSize < new_size) {
-    return -1;
-  }
-  Handle<JSArrayBuffer> buffer = NewArrayBuffer(isolate, new_size);
-  if (buffer.is_null()) return -1;
-  Address new_mem_start = static_cast<Address>(buffer->backing_store());
-  if (old_size != 0) {
-    memcpy(new_mem_start, old_mem_start, old_size);
-  }
-  SetInstanceMemory(instance, *buffer);
-  Handle<FixedArray> code_table = instance->get_compiled_module()->code_table();
-  RelocateMemoryReferencesInCode(code_table, old_mem_start, new_mem_start,
-                                 old_size, new_size);
-  if (instance->has_memory_object()) {
-    instance->get_memory_object()->set_buffer(*buffer);
+      kV8MaxWasmMemoryPages * WasmModule::kPageSize < new_size) {
+    return Handle<JSArrayBuffer>::null();
   }
 
+  Handle<JSArrayBuffer> new_buffer;
+  if (!old_buffer.is_null() && old_buffer->has_guard_region()) {
+    // We don't move the backing store, we simply change the protection to make
+    // more of it accessible.
+    base::OS::Unprotect(old_buffer->backing_store(), new_size);
+    reinterpret_cast<v8::Isolate*>(isolate)
+        ->AdjustAmountOfExternalAllocatedMemory(pages * WasmModule::kPageSize);
+    Handle<Object> new_size_object =
+        isolate->factory()->NewNumberFromSize(new_size);
+    old_buffer->set_byte_length(*new_size_object);
+    new_buffer = old_buffer;
+  } else {
+    const bool enable_guard_regions = false;
+    new_buffer = NewArrayBuffer(isolate, new_size, enable_guard_regions);
+    if (new_buffer.is_null()) return new_buffer;
+    Address new_mem_start = static_cast<Address>(new_buffer->backing_store());
+    if (old_size != 0) {
+      memcpy(new_mem_start, old_mem_start, old_size);
+    }
+  }
+  return new_buffer;
+}
+
+void UncheckedUpdateInstanceMemory(Isolate* isolate,
+                                   Handle<WasmInstanceObject> instance,
+                                   Address old_mem_start, uint32_t old_size) {
+  DCHECK(instance->has_memory_buffer());
+  Handle<JSArrayBuffer> new_buffer(instance->memory_buffer());
+  uint32_t new_size = new_buffer->byte_length()->Number();
+  DCHECK(new_size <= std::numeric_limits<uint32_t>::max());
+  Address new_mem_start = static_cast<Address>(new_buffer->backing_store());
+  DCHECK_NOT_NULL(new_mem_start);
+  Handle<FixedArray> code_table = instance->compiled_module()->code_table();
+  RelocateMemoryReferencesInCode(
+      code_table, instance->compiled_module()->module()->num_imported_functions,
+      old_mem_start, new_mem_start, old_size, new_size);
+}
+
+int32_t wasm::GrowWebAssemblyMemory(Isolate* isolate,
+                                    Handle<WasmMemoryObject> receiver,
+                                    uint32_t pages) {
+  DCHECK(WasmJs::IsWasmMemoryObject(isolate, receiver));
+  Handle<WasmMemoryObject> memory_object =
+      handle(WasmMemoryObject::cast(*receiver));
+  MaybeHandle<JSArrayBuffer> memory_buffer = handle(memory_object->buffer());
+  Handle<JSArrayBuffer> old_buffer;
+  uint32_t old_size = 0;
+  Address old_mem_start = nullptr;
+  if (memory_buffer.ToHandle(&old_buffer) &&
+      old_buffer->backing_store() != nullptr) {
+    old_size = old_buffer->byte_length()->Number();
+    old_mem_start = static_cast<Address>(old_buffer->backing_store());
+  }
+  // Return current size if grow by 0
+  if (pages == 0) {
+    DCHECK(old_size % WasmModule::kPageSize == 0);
+    return (old_size / WasmModule::kPageSize);
+  }
+  Handle<JSArrayBuffer> new_buffer;
+  if (!memory_object->has_instances_link()) {
+    // Memory object does not have an instance associated with it, just grow
+    uint32_t max_pages;
+    if (memory_object->has_maximum_pages()) {
+      max_pages = static_cast<uint32_t>(memory_object->maximum_pages());
+      if (kV8MaxWasmMemoryPages < max_pages) return -1;
+    } else {
+      max_pages = kV8MaxWasmMemoryPages;
+    }
+    new_buffer = GrowMemoryBuffer(isolate, memory_buffer, pages, max_pages);
+    if (new_buffer.is_null()) return -1;
+  } else {
+    Handle<WasmInstanceWrapper> instance_wrapper(
+        memory_object->instances_link());
+    DCHECK(WasmInstanceWrapper::IsWasmInstanceWrapper(*instance_wrapper));
+    DCHECK(instance_wrapper->has_instance());
+    Handle<WasmInstanceObject> instance = instance_wrapper->instance_object();
+    DCHECK(IsWasmInstance(*instance));
+    uint32_t max_pages = GetMaxInstanceMemoryPages(isolate, instance);
+
+    // Grow memory object buffer and update instances associated with it.
+    new_buffer = GrowMemoryBuffer(isolate, memory_buffer, pages, max_pages);
+    if (new_buffer.is_null()) return -1;
+    DCHECK(!instance_wrapper->has_previous());
+    SetInstanceMemory(instance, *new_buffer);
+    UncheckedUpdateInstanceMemory(isolate, instance, old_mem_start, old_size);
+    while (instance_wrapper->has_next()) {
+      instance_wrapper = instance_wrapper->next_wrapper();
+      DCHECK(WasmInstanceWrapper::IsWasmInstanceWrapper(*instance_wrapper));
+      Handle<WasmInstanceObject> instance = instance_wrapper->instance_object();
+      DCHECK(IsWasmInstance(*instance));
+      SetInstanceMemory(instance, *new_buffer);
+      UncheckedUpdateInstanceMemory(isolate, instance, old_mem_start, old_size);
+    }
+  }
+  memory_object->set_buffer(*new_buffer);
   DCHECK(old_size % WasmModule::kPageSize == 0);
   return (old_size / WasmModule::kPageSize);
 }
 
+int32_t wasm::GrowMemory(Isolate* isolate, Handle<WasmInstanceObject> instance,
+                         uint32_t pages) {
+  if (!IsWasmInstance(*instance)) return -1;
+  if (pages == 0) return GetInstanceMemorySize(isolate, instance);
+  Handle<WasmInstanceObject> instance_obj(WasmInstanceObject::cast(*instance));
+  if (!instance_obj->has_memory_object()) {
+    // No other instances to grow, grow just the one.
+    MaybeHandle<JSArrayBuffer> instance_buffer =
+        GetInstanceMemory(isolate, instance);
+    Handle<JSArrayBuffer> old_buffer;
+    uint32_t old_size = 0;
+    Address old_mem_start = nullptr;
+    if (instance_buffer.ToHandle(&old_buffer) &&
+        old_buffer->backing_store() != nullptr) {
+      old_size = old_buffer->byte_length()->Number();
+      old_mem_start = static_cast<Address>(old_buffer->backing_store());
+    }
+    uint32_t max_pages = GetMaxInstanceMemoryPages(isolate, instance_obj);
+    Handle<JSArrayBuffer> buffer =
+        GrowMemoryBuffer(isolate, instance_buffer, pages, max_pages);
+    if (buffer.is_null()) return -1;
+    SetInstanceMemory(instance, *buffer);
+    UncheckedUpdateInstanceMemory(isolate, instance, old_mem_start, old_size);
+    DCHECK(old_size % WasmModule::kPageSize == 0);
+    return (old_size / WasmModule::kPageSize);
+  } else {
+    return GrowWebAssemblyMemory(isolate, handle(instance_obj->memory_object()),
+                                 pages);
+  }
+}
+
+void wasm::GrowDispatchTables(Isolate* isolate,
+                              Handle<FixedArray> dispatch_tables,
+                              uint32_t old_size, uint32_t count) {
+  DCHECK_EQ(0, dispatch_tables->length() % 4);
+  for (int i = 0; i < dispatch_tables->length(); i += 4) {
+    Handle<FixedArray> old_function_table(
+        FixedArray::cast(dispatch_tables->get(i + 2)));
+    Handle<FixedArray> old_signature_table(
+        FixedArray::cast(dispatch_tables->get(i + 3)));
+    Handle<FixedArray> new_function_table =
+        isolate->factory()->CopyFixedArrayAndGrow(old_function_table, count);
+    Handle<FixedArray> new_signature_table =
+        isolate->factory()->CopyFixedArrayAndGrow(old_signature_table, count);
+
+    // Get code table for the instance
+    Handle<WasmInstanceObject> instance(
+        WasmInstanceObject::cast(dispatch_tables->get(i)));
+    Handle<FixedArray> code_table(instance->compiled_module()->code_table());
+
+    // Relocate size references
+    RelocateTableSizeReferences(code_table, old_size, old_size + count);
+
+    // Replace references of old tables with new tables.
+    for (int j = 0; j < code_table->length(); ++j) {
+      if (!code_table->get(j)->IsCode()) continue;
+      Handle<Code> code = Handle<Code>(Code::cast(code_table->get(j)));
+      ReplaceReferenceInCode(code, old_function_table, new_function_table);
+      ReplaceReferenceInCode(code, old_signature_table, new_signature_table);
+    }
+
+    // Update dispatch tables with new function/signature tables
+    dispatch_tables->set(i + 2, *new_function_table);
+    dispatch_tables->set(i + 3, *new_signature_table);
+  }
+}
+
 void testing::ValidateInstancesChain(Isolate* isolate,
-                                     Handle<JSObject> wasm_module,
+                                     Handle<WasmModuleObject> module_obj,
                                      int instance_count) {
   CHECK_GE(instance_count, 0);
   DisallowHeapAllocation no_gc;
-  WasmCompiledModule* compiled_module =
-      WasmCompiledModule::cast(wasm_module->GetInternalField(0));
+  WasmCompiledModule* compiled_module = module_obj->compiled_module();
   CHECK_EQ(JSObject::cast(compiled_module->ptr_to_weak_wasm_module()->value()),
-           *wasm_module);
+           *module_obj);
   Object* prev = nullptr;
   int found_instances = compiled_module->has_weak_owning_instance() ? 1 : 0;
   WasmCompiledModule* current_instance = compiled_module;
   while (current_instance->has_weak_next_instance()) {
     CHECK((prev == nullptr && !current_instance->has_weak_prev_instance()) ||
           current_instance->ptr_to_weak_prev_instance()->value() == prev);
-    CHECK_EQ(current_instance->ptr_to_weak_wasm_module()->value(),
-             *wasm_module);
+    CHECK_EQ(current_instance->ptr_to_weak_wasm_module()->value(), *module_obj);
     CHECK(IsWasmInstance(
         current_instance->ptr_to_weak_owning_instance()->value()));
     prev = current_instance;
@@ -2126,63 +2552,222 @@ void testing::ValidateInstancesChain(Isolate* isolate,
 }
 
 void testing::ValidateModuleState(Isolate* isolate,
-                                  Handle<JSObject> wasm_module) {
+                                  Handle<WasmModuleObject> module_obj) {
   DisallowHeapAllocation no_gc;
-  WasmCompiledModule* compiled_module =
-      WasmCompiledModule::cast(wasm_module->GetInternalField(0));
+  WasmCompiledModule* compiled_module = module_obj->compiled_module();
   CHECK(compiled_module->has_weak_wasm_module());
-  CHECK_EQ(compiled_module->ptr_to_weak_wasm_module()->value(), *wasm_module);
+  CHECK_EQ(compiled_module->ptr_to_weak_wasm_module()->value(), *module_obj);
   CHECK(!compiled_module->has_weak_prev_instance());
   CHECK(!compiled_module->has_weak_next_instance());
   CHECK(!compiled_module->has_weak_owning_instance());
 }
 
 void testing::ValidateOrphanedInstance(Isolate* isolate,
-                                       Handle<JSObject> object) {
+                                       Handle<WasmInstanceObject> instance) {
   DisallowHeapAllocation no_gc;
-  WasmInstanceObject* instance = WasmInstanceObject::cast(*object);
-  WasmCompiledModule* compiled_module = instance->get_compiled_module();
+  WasmCompiledModule* compiled_module = instance->compiled_module();
   CHECK(compiled_module->has_weak_wasm_module());
   CHECK(compiled_module->ptr_to_weak_wasm_module()->cleared());
 }
 
-void WasmCompiledModule::RecreateModuleWrapper(Isolate* isolate,
-                                               Handle<FixedArray> array) {
-  Handle<WasmCompiledModule> compiled_module(
-      reinterpret_cast<WasmCompiledModule*>(*array), isolate);
+Handle<JSArray> wasm::GetImports(Isolate* isolate,
+                                 Handle<WasmModuleObject> module_object) {
+  Handle<WasmCompiledModule> compiled_module(module_object->compiled_module(),
+                                             isolate);
+  Factory* factory = isolate->factory();
 
-  WasmModule* module = nullptr;
+  Handle<String> module_string = factory->InternalizeUtf8String("module");
+  Handle<String> name_string = factory->InternalizeUtf8String("name");
+  Handle<String> kind_string = factory->InternalizeUtf8String("kind");
+
+  Handle<String> function_string = factory->InternalizeUtf8String("function");
+  Handle<String> table_string = factory->InternalizeUtf8String("table");
+  Handle<String> memory_string = factory->InternalizeUtf8String("memory");
+  Handle<String> global_string = factory->InternalizeUtf8String("global");
+
+  // Create the result array.
+  WasmModule* module = compiled_module->module();
+  int num_imports = static_cast<int>(module->import_table.size());
+  Handle<JSArray> array_object = factory->NewJSArray(FAST_ELEMENTS, 0, 0);
+  Handle<FixedArray> storage = factory->NewFixedArray(num_imports);
+  JSArray::SetContent(array_object, storage);
+  array_object->set_length(Smi::FromInt(num_imports));
+
+  Handle<JSFunction> object_function =
+      Handle<JSFunction>(isolate->native_context()->object_function(), isolate);
+
+  // Populate the result array.
+  for (int index = 0; index < num_imports; ++index) {
+    WasmImport& import = module->import_table[index];
+
+    Handle<JSObject> entry = factory->NewJSObject(object_function);
+
+    Handle<String> import_kind;
+    switch (import.kind) {
+      case kExternalFunction:
+        import_kind = function_string;
+        break;
+      case kExternalTable:
+        import_kind = table_string;
+        break;
+      case kExternalMemory:
+        import_kind = memory_string;
+        break;
+      case kExternalGlobal:
+        import_kind = global_string;
+        break;
+      default:
+        UNREACHABLE();
+    }
+
+    MaybeHandle<String> import_module =
+        WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+            isolate, compiled_module, import.module_name_offset,
+            import.module_name_length);
+
+    MaybeHandle<String> import_name =
+        WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+            isolate, compiled_module, import.field_name_offset,
+            import.field_name_length);
+
+    JSObject::AddProperty(entry, module_string, import_module.ToHandleChecked(),
+                          NONE);
+    JSObject::AddProperty(entry, name_string, import_name.ToHandleChecked(),
+                          NONE);
+    JSObject::AddProperty(entry, kind_string, import_kind, NONE);
+
+    storage->set(index, *entry);
+  }
+
+  return array_object;
+}
+
+Handle<JSArray> wasm::GetExports(Isolate* isolate,
+                                 Handle<WasmModuleObject> module_object) {
+  Handle<WasmCompiledModule> compiled_module(module_object->compiled_module(),
+                                             isolate);
+  Factory* factory = isolate->factory();
+
+  Handle<String> name_string = factory->InternalizeUtf8String("name");
+  Handle<String> kind_string = factory->InternalizeUtf8String("kind");
+
+  Handle<String> function_string = factory->InternalizeUtf8String("function");
+  Handle<String> table_string = factory->InternalizeUtf8String("table");
+  Handle<String> memory_string = factory->InternalizeUtf8String("memory");
+  Handle<String> global_string = factory->InternalizeUtf8String("global");
+
+  // Create the result array.
+  WasmModule* module = compiled_module->module();
+  int num_exports = static_cast<int>(module->export_table.size());
+  Handle<JSArray> array_object = factory->NewJSArray(FAST_ELEMENTS, 0, 0);
+  Handle<FixedArray> storage = factory->NewFixedArray(num_exports);
+  JSArray::SetContent(array_object, storage);
+  array_object->set_length(Smi::FromInt(num_exports));
+
+  Handle<JSFunction> object_function =
+      Handle<JSFunction>(isolate->native_context()->object_function(), isolate);
+
+  // Populate the result array.
+  for (int index = 0; index < num_exports; ++index) {
+    WasmExport& exp = module->export_table[index];
+
+    Handle<String> export_kind;
+    switch (exp.kind) {
+      case kExternalFunction:
+        export_kind = function_string;
+        break;
+      case kExternalTable:
+        export_kind = table_string;
+        break;
+      case kExternalMemory:
+        export_kind = memory_string;
+        break;
+      case kExternalGlobal:
+        export_kind = global_string;
+        break;
+      default:
+        UNREACHABLE();
+    }
+
+    Handle<JSObject> entry = factory->NewJSObject(object_function);
+
+    MaybeHandle<String> export_name =
+        WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+            isolate, compiled_module, exp.name_offset, exp.name_length);
+
+    JSObject::AddProperty(entry, name_string, export_name.ToHandleChecked(),
+                          NONE);
+    JSObject::AddProperty(entry, kind_string, export_kind, NONE);
+
+    storage->set(index, *entry);
+  }
+
+  return array_object;
+}
+
+Handle<JSArray> wasm::GetCustomSections(Isolate* isolate,
+                                        Handle<WasmModuleObject> module_object,
+                                        Handle<String> name,
+                                        ErrorThrower* thrower) {
+  Handle<WasmCompiledModule> compiled_module(module_object->compiled_module(),
+                                             isolate);
+  Factory* factory = isolate->factory();
+
+  std::vector<CustomSectionOffset> custom_sections;
   {
-    Handle<SeqOneByteString> module_bytes = compiled_module->module_bytes();
-    // We parse the module again directly from the module bytes, so
-    // the underlying storage must not be moved meanwhile.
-    DisallowHeapAllocation no_allocation;
+    DisallowHeapAllocation no_gc;  // for raw access to string bytes.
+    Handle<SeqOneByteString> module_bytes(compiled_module->module_bytes(),
+                                          isolate);
     const byte* start =
         reinterpret_cast<const byte*>(module_bytes->GetCharsAddress());
     const byte* end = start + module_bytes->length();
-    // TODO(titzer): remember the module origin in the compiled_module
-    // For now, we assume serialized modules did not originate from asm.js.
-    ModuleResult result =
-        DecodeWasmModule(isolate, start, end, false, kWasmOrigin);
-    CHECK(result.ok());
-    CHECK_NOT_NULL(result.val);
-    module = const_cast<WasmModule*>(result.val);
+    custom_sections = DecodeCustomSections(start, end);
+  }
+
+  std::vector<Handle<Object>> matching_sections;
+
+  // Gather matching sections.
+  for (auto section : custom_sections) {
+    MaybeHandle<String> section_name =
+        WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+            isolate, compiled_module, section.name_offset, section.name_length);
+
+    if (!name->Equals(*section_name.ToHandleChecked())) continue;
+
+    // Make a copy of the payload data in the section.
+    bool is_external;  // Set by TryAllocateBackingStore
+    void* memory = TryAllocateBackingStore(isolate, section.payload_length,
+                                           false, is_external);
+
+    Handle<Object> section_data = factory->undefined_value();
+    if (memory) {
+      Handle<JSArrayBuffer> buffer = isolate->factory()->NewJSArrayBuffer();
+      JSArrayBuffer::Setup(buffer, isolate, is_external, memory,
+                           static_cast<int>(section.payload_length));
+      DisallowHeapAllocation no_gc;  // for raw access to string bytes.
+      Handle<SeqOneByteString> module_bytes(compiled_module->module_bytes(),
+                                            isolate);
+      const byte* start =
+          reinterpret_cast<const byte*>(module_bytes->GetCharsAddress());
+      memcpy(memory, start + section.payload_offset, section.payload_length);
+      section_data = buffer;
+    } else {
+      thrower->RangeError("out of memory allocating custom section data");
+      return Handle<JSArray>();
+    }
+
+    matching_sections.push_back(section_data);
   }
 
-  Handle<WasmModuleWrapper> module_wrapper =
-      WasmModuleWrapper::New(isolate, module);
+  int num_custom_sections = static_cast<int>(matching_sections.size());
+  Handle<JSArray> array_object = factory->NewJSArray(FAST_ELEMENTS, 0, 0);
+  Handle<FixedArray> storage = factory->NewFixedArray(num_custom_sections);
+  JSArray::SetContent(array_object, storage);
+  array_object->set_length(Smi::FromInt(num_custom_sections));
 
-  compiled_module->set_module_wrapper(module_wrapper);
-  DCHECK(WasmCompiledModule::IsWasmCompiledModule(*compiled_module));
-}
+  for (int i = 0; i < num_custom_sections; i++) {
+    storage->set(i, *matching_sections[i]);
+  }
 
-MaybeHandle<String> WasmCompiledModule::GetFunctionName(
-    Handle<WasmCompiledModule> compiled_module, uint32_t func_index) {
-  DCHECK_LT(func_index, compiled_module->module()->functions.size());
-  WasmFunction& function = compiled_module->module()->functions[func_index];
-  Isolate* isolate = compiled_module->GetIsolate();
-  MaybeHandle<String> string = ExtractStringFromModuleBytes(
-      isolate, compiled_module, function.name_offset, function.name_length);
-  if (!string.is_null()) return string.ToHandleChecked();
-  return {};
+  return array_object;
 }
diff --git a/deps/v8/src/wasm/wasm-module.h b/deps/v8/src/wasm/wasm-module.h
index 2ad46e21b6..2f368a7391 100644
--- a/deps/v8/src/wasm/wasm-module.h
+++ b/deps/v8/src/wasm/wasm-module.h
@@ -8,6 +8,7 @@
 #include <memory>
 
 #include "src/api.h"
+#include "src/debug/debug-interface.h"
 #include "src/globals.h"
 #include "src/handles.h"
 #include "src/parsing/preparse-data.h"
@@ -22,6 +23,8 @@ namespace internal {
 class WasmCompiledModule;
 class WasmDebugInfo;
 class WasmModuleObject;
+class WasmInstanceObject;
+class WasmMemoryObject;
 
 namespace compiler {
 class CallDescriptor;
@@ -31,11 +34,8 @@ class WasmCompilationUnit;
 namespace wasm {
 class ErrorThrower;
 
-const size_t kMaxModuleSize = 1024 * 1024 * 1024;
-const size_t kMaxFunctionSize = 128 * 1024;
-const size_t kMaxStringSize = 256;
 const uint32_t kWasmMagic = 0x6d736100;
-const uint32_t kWasmVersion = 0x0d;
+const uint32_t kWasmVersion = 0x01;
 
 const uint8_t kWasmFunctionTypeForm = 0x60;
 const uint8_t kWasmAnyFunctionTypeForm = 0x70;
@@ -63,7 +63,6 @@ inline bool IsValidSectionCode(uint8_t byte) {
 const char* SectionName(WasmSectionCode code);
 
 // Constants for fixed-size elements within a module.
-static const uint32_t kMaxReturnCount = 1;
 static const uint8_t kResizableMaximumFlag = 1;
 static const int32_t kInvalidFunctionIndex = -1;
 
@@ -118,7 +117,7 @@ struct WasmFunction {
 
 // Static representation of a wasm global variable.
 struct WasmGlobal {
-  LocalType type;        // type of the global.
+  ValueType type;        // type of the global.
   bool mutability;       // {true} if mutable.
   WasmInitExpr init;     // the initialization expression of the global.
   uint32_t offset;       // offset into global memory.
@@ -170,21 +169,18 @@ struct WasmExport {
   uint32_t index;         // index into the respective space.
 };
 
-enum ModuleOrigin { kWasmOrigin, kAsmJsOrigin };
+enum ModuleOrigin : uint8_t { kWasmOrigin, kAsmJsOrigin };
+struct ModuleWireBytes;
 
 // Static representation of a module.
 struct V8_EXPORT_PRIVATE WasmModule {
   static const uint32_t kPageSize = 0x10000;    // Page size, 64kb.
   static const uint32_t kMinMemPages = 1;       // Minimum memory size = 64kb
-  static const size_t kV8MaxPages = 16384;      // Maximum memory size = 1gb
-  static const size_t kSpecMaxPages = 65536;    // Maximum according to the spec
-  static const size_t kV8MaxTableSize = 16 * 1024 * 1024;
 
   Zone* owned_zone;
-  const byte* module_start = nullptr;  // starting address for the module bytes
-  const byte* module_end = nullptr;    // end address for the module bytes
   uint32_t min_mem_pages = 0;  // minimum size of the memory in 64k pages
   uint32_t max_mem_pages = 0;  // maximum size of the memory in 64k pages
+  bool has_max_mem = false;    // try if a maximum memory size exists
   bool has_memory = false;     // true if the memory was defined or imported
   bool mem_export = false;     // true if the memory is exported
   // TODO(wasm): reconcile start function index being an int with
@@ -214,56 +210,23 @@ struct V8_EXPORT_PRIVATE WasmModule {
   // switch to libc-2.21 or higher.
   std::unique_ptr<base::Semaphore> pending_tasks;
 
-  WasmModule() : WasmModule(nullptr, nullptr) {}
-  WasmModule(Zone* owned_zone, const byte* module_start);
+  WasmModule() : WasmModule(nullptr) {}
+  WasmModule(Zone* owned_zone);
   ~WasmModule() {
     if (owned_zone) delete owned_zone;
   }
 
-  // Get a string stored in the module bytes representing a name.
-  WasmName GetName(uint32_t offset, uint32_t length) const {
-    if (length == 0) return {"<?>", 3};  // no name.
-    CHECK(BoundsCheck(offset, offset + length));
-    DCHECK_GE(static_cast<int>(length), 0);
-    return {reinterpret_cast<const char*>(module_start + offset),
-            static_cast<int>(length)};
-  }
-
-  // Get a string stored in the module bytes representing a function name.
-  WasmName GetName(WasmFunction* function) const {
-    return GetName(function->name_offset, function->name_length);
-  }
-
-  // Get a string stored in the module bytes representing a name.
-  WasmName GetNameOrNull(uint32_t offset, uint32_t length) const {
-    if (offset == 0 && length == 0) return {NULL, 0};  // no name.
-    CHECK(BoundsCheck(offset, offset + length));
-    DCHECK_GE(static_cast<int>(length), 0);
-    return {reinterpret_cast<const char*>(module_start + offset),
-            static_cast<int>(length)};
-  }
-
-  // Get a string stored in the module bytes representing a function name.
-  WasmName GetNameOrNull(const WasmFunction* function) const {
-    return GetNameOrNull(function->name_offset, function->name_length);
-  }
-
-  // Checks the given offset range is contained within the module bytes.
-  bool BoundsCheck(uint32_t start, uint32_t end) const {
-    size_t size = module_end - module_start;
-    return start <= size && end <= size;
-  }
-
   // Creates a new instantiation of the module in the given isolate.
-  static MaybeHandle<JSObject> Instantiate(Isolate* isolate,
-                                           ErrorThrower* thrower,
-                                           Handle<JSObject> wasm_module,
-                                           Handle<JSReceiver> ffi,
-                                           Handle<JSArrayBuffer> memory);
+  static MaybeHandle<WasmInstanceObject> Instantiate(
+      Isolate* isolate, ErrorThrower* thrower,
+      Handle<WasmModuleObject> wasm_module, Handle<JSReceiver> ffi,
+      Handle<JSArrayBuffer> memory = Handle<JSArrayBuffer>::null());
 
   MaybeHandle<WasmCompiledModule> CompileFunctions(
       Isolate* isolate, Handle<Managed<WasmModule>> module_wrapper,
-      ErrorThrower* thrower) const;
+      ErrorThrower* thrower, const ModuleWireBytes& wire_bytes,
+      Handle<Script> asm_js_script,
+      Vector<const byte> asm_js_offset_table_bytes) const;
 };
 
 typedef Managed<WasmModule> WasmModuleWrapper;
@@ -272,11 +235,10 @@ typedef Managed<WasmModule> WasmModuleWrapper;
 struct WasmInstance {
   const WasmModule* module;  // static representation of the module.
   // -- Heap allocated --------------------------------------------------------
-  Handle<JSObject> js_object;            // JavaScript module object.
   Handle<Context> context;               // JavaScript native context.
-  Handle<JSArrayBuffer> mem_buffer;      // Handle to array buffer of memory.
-  Handle<JSArrayBuffer> globals_buffer;  // Handle to array buffer of globals.
   std::vector<Handle<FixedArray>> function_tables;  // indirect function tables.
+  std::vector<Handle<FixedArray>>
+      signature_tables;                    // indirect signature tables.
   std::vector<Handle<Code>> function_code;  // code objects for each function.
   // -- raw memory ------------------------------------------------------------
   byte* mem_start = nullptr;  // start of linear memory.
@@ -287,15 +249,67 @@ struct WasmInstance {
   explicit WasmInstance(const WasmModule* m)
       : module(m),
         function_tables(m->function_tables.size()),
+        signature_tables(m->function_tables.size()),
         function_code(m->functions.size()) {}
 };
 
+// Interface to the storage (wire bytes) of a wasm module.
+// It is illegal for anyone receiving a ModuleWireBytes to store pointers based
+// on module_bytes, as this storage is only guaranteed to be alive as long as
+// this struct is alive.
+struct V8_EXPORT_PRIVATE ModuleWireBytes {
+  ModuleWireBytes(Vector<const byte> module_bytes)
+      : module_bytes(module_bytes) {}
+  ModuleWireBytes(const byte* start, const byte* end)
+      : module_bytes(start, static_cast<int>(end - start)) {
+    DCHECK_GE(kMaxInt, end - start);
+  }
+
+  const Vector<const byte> module_bytes;
+
+  // Get a string stored in the module bytes representing a name.
+  WasmName GetName(uint32_t offset, uint32_t length) const {
+    if (length == 0) return {"<?>", 3};  // no name.
+    CHECK(BoundsCheck(offset, length));
+    DCHECK_GE(length, 0);
+    return Vector<const char>::cast(
+        module_bytes.SubVector(offset, offset + length));
+  }
+
+  // Get a string stored in the module bytes representing a function name.
+  WasmName GetName(const WasmFunction* function) const {
+    return GetName(function->name_offset, function->name_length);
+  }
+
+  // Get a string stored in the module bytes representing a name.
+  WasmName GetNameOrNull(uint32_t offset, uint32_t length) const {
+    if (offset == 0 && length == 0) return {NULL, 0};  // no name.
+    CHECK(BoundsCheck(offset, length));
+    DCHECK_GE(length, 0);
+    return Vector<const char>::cast(
+        module_bytes.SubVector(offset, offset + length));
+  }
+
+  // Get a string stored in the module bytes representing a function name.
+  WasmName GetNameOrNull(const WasmFunction* function) const {
+    return GetNameOrNull(function->name_offset, function->name_length);
+  }
+
+  // Checks the given offset range is contained within the module bytes.
+  bool BoundsCheck(uint32_t offset, uint32_t length) const {
+    uint32_t size = static_cast<uint32_t>(module_bytes.length());
+    return offset <= size && length <= size - offset;
+  }
+};
+
 // Interface provided to the decoder/graph builder which contains only
 // minimal information about the globals, functions, and function tables.
 struct V8_EXPORT_PRIVATE ModuleEnv {
+  ModuleEnv(const WasmModule* module, WasmInstance* instance)
+      : module(module), instance(instance) {}
+
   const WasmModule* module;
   WasmInstance* instance;
-  ModuleOrigin origin;
 
   bool IsValidGlobal(uint32_t index) const {
     return module && index < module->globals.size();
@@ -309,7 +323,7 @@ struct V8_EXPORT_PRIVATE ModuleEnv {
   bool IsValidTable(uint32_t index) const {
     return module && index < module->function_tables.size();
   }
-  LocalType GetGlobalType(uint32_t index) {
+  ValueType GetGlobalType(uint32_t index) {
     DCHECK(IsValidGlobal(index));
     return module->globals[index].type;
   }
@@ -326,7 +340,7 @@ struct V8_EXPORT_PRIVATE ModuleEnv {
     return &module->function_tables[index];
   }
 
-  bool asm_js() { return origin == kAsmJsOrigin; }
+  bool asm_js() { return module->origin == kAsmJsOrigin; }
 
   Handle<Code> GetFunctionCode(uint32_t index) {
     DCHECK_NOT_NULL(instance);
@@ -341,42 +355,33 @@ struct V8_EXPORT_PRIVATE ModuleEnv {
       Zone* zone, compiler::CallDescriptor* descriptor);
 };
 
+// A ModuleEnv together with ModuleWireBytes.
+struct ModuleBytesEnv : public ModuleEnv, public ModuleWireBytes {
+  ModuleBytesEnv(const WasmModule* module, WasmInstance* instance,
+                 Vector<const byte> module_bytes)
+      : ModuleEnv(module, instance), ModuleWireBytes(module_bytes) {}
+  ModuleBytesEnv(const WasmModule* module, WasmInstance* instance,
+                 const ModuleWireBytes& wire_bytes)
+      : ModuleEnv(module, instance), ModuleWireBytes(wire_bytes) {}
+};
+
 // A helper for printing out the names of functions.
 struct WasmFunctionName {
+  WasmFunctionName(const WasmFunction* function, ModuleBytesEnv* module_env)
+      : function_(function), name_(module_env->GetNameOrNull(function)) {}
+
   const WasmFunction* function_;
-  const WasmModule* module_;
-  WasmFunctionName(const WasmFunction* function, const ModuleEnv* menv)
-      : function_(function), module_(menv ? menv->module : nullptr) {}
+  WasmName name_;
 };
 
 std::ostream& operator<<(std::ostream& os, const WasmModule& module);
 std::ostream& operator<<(std::ostream& os, const WasmFunction& function);
 std::ostream& operator<<(std::ostream& os, const WasmFunctionName& name);
 
-// Extract a function name from the given wasm instance.
-// Returns "<WASM UNNAMED>" if no instance is passed, the function is unnamed or
-// the name is not a valid UTF-8 string.
-// TODO(5620): Refactor once we always get a wasm instance.
-Handle<String> GetWasmFunctionName(Isolate* isolate, Handle<Object> instance,
-                                   uint32_t func_index);
-
-// Return the binary source bytes of a wasm module.
-Handle<SeqOneByteString> GetWasmBytes(Handle<JSObject> wasm);
-
 // Get the debug info associated with the given wasm object.
 // If no debug info exists yet, it is created automatically.
 Handle<WasmDebugInfo> GetDebugInfo(Handle<JSObject> wasm);
 
-// Return the number of functions in the given wasm object.
-int GetNumberOfFunctions(Handle<JSObject> wasm);
-
-// Create and export JSFunction
-Handle<JSFunction> WrapExportCodeAsJSFunction(Isolate* isolate,
-                                              Handle<Code> export_code,
-                                              Handle<String> name,
-                                              FunctionSig* sig, int func_index,
-                                              Handle<JSObject> instance);
-
 // Check whether the given object represents a WebAssembly.Instance instance.
 // This checks the number and type of internal fields, so it's not 100 percent
 // secure. If it turns out that we need more complete checks, we could add a
@@ -384,26 +389,26 @@ Handle<JSFunction> WrapExportCodeAsJSFunction(Isolate* isolate,
 // else.
 bool IsWasmInstance(Object* instance);
 
-// Return the compiled module object for this WASM instance.
-WasmCompiledModule* GetCompiledModule(Object* wasm_instance);
-
-// Check whether the wasm module was generated from asm.js code.
-bool WasmIsAsmJs(Object* instance, Isolate* isolate);
-
 // Get the script of the wasm module. If the origin of the module is asm.js, the
 // returned Script will be a JavaScript Script of Script::TYPE_NORMAL, otherwise
 // it's of type TYPE_WASM.
 Handle<Script> GetScript(Handle<JSObject> instance);
 
-// Get the asm.js source position for the given byte offset in the given
-// function.
-int GetAsmWasmSourcePosition(Handle<JSObject> instance, int func_index,
-                             int byte_offset);
-
 V8_EXPORT_PRIVATE MaybeHandle<WasmModuleObject> CreateModuleObjectFromBytes(
     Isolate* isolate, const byte* start, const byte* end, ErrorThrower* thrower,
     ModuleOrigin origin, Handle<Script> asm_js_script,
-    const byte* asm_offset_tables_start, const byte* asm_offset_tables_end);
+    Vector<const byte> asm_offset_table);
+
+V8_EXPORT_PRIVATE bool IsWasmCodegenAllowed(Isolate* isolate,
+                                            Handle<Context> context);
+
+V8_EXPORT_PRIVATE Handle<JSArray> GetImports(Isolate* isolate,
+                                             Handle<WasmModuleObject> module);
+V8_EXPORT_PRIVATE Handle<JSArray> GetExports(Isolate* isolate,
+                                             Handle<WasmModuleObject> module);
+V8_EXPORT_PRIVATE Handle<JSArray> GetCustomSections(
+    Isolate* isolate, Handle<WasmModuleObject> module, Handle<String> name,
+    ErrorThrower* thrower);
 
 V8_EXPORT_PRIVATE bool ValidateModuleBytes(Isolate* isolate, const byte* start,
                                            const byte* end,
@@ -414,33 +419,44 @@ V8_EXPORT_PRIVATE bool ValidateModuleBytes(Isolate* isolate, const byte* start,
 int GetFunctionCodeOffset(Handle<WasmCompiledModule> compiled_module,
                           int func_index);
 
-// Translate from byte offset in the module to function number and byte offset
-// within that function, encoded as line and column in the position info.
-bool GetPositionInfo(Handle<WasmCompiledModule> compiled_module,
-                     uint32_t position, Script::PositionInfo* info);
-
 // Assumed to be called with a code object associated to a wasm module instance.
 // Intended to be called from runtime functions.
 // Returns nullptr on failing to get owning instance.
-Object* GetOwningWasmInstance(Code* code);
+WasmInstanceObject* GetOwningWasmInstance(Code* code);
 
-MaybeHandle<JSArrayBuffer> GetInstanceMemory(Isolate* isolate,
-                                             Handle<JSObject> instance);
+MaybeHandle<JSArrayBuffer> GetInstanceMemory(
+    Isolate* isolate, Handle<WasmInstanceObject> instance);
 
-int32_t GetInstanceMemorySize(Isolate* isolate, Handle<JSObject> instance);
+int32_t GetInstanceMemorySize(Isolate* isolate,
+                              Handle<WasmInstanceObject> instance);
 
-int32_t GrowInstanceMemory(Isolate* isolate, Handle<JSObject> instance,
-                           uint32_t pages);
+int32_t GrowInstanceMemory(Isolate* isolate,
+                           Handle<WasmInstanceObject> instance, uint32_t pages);
+
+Handle<JSArrayBuffer> NewArrayBuffer(Isolate* isolate, size_t size,
+                                     bool enable_guard_regions);
+
+int32_t GrowWebAssemblyMemory(Isolate* isolate,
+                              Handle<WasmMemoryObject> receiver,
+                              uint32_t pages);
+
+int32_t GrowMemory(Isolate* isolate, Handle<WasmInstanceObject> instance,
+                   uint32_t pages);
 
 void UpdateDispatchTables(Isolate* isolate, Handle<FixedArray> dispatch_tables,
                           int index, Handle<JSFunction> js_function);
 
+void GrowDispatchTables(Isolate* isolate, Handle<FixedArray> dispatch_tables,
+                        uint32_t old_size, uint32_t count);
+
 namespace testing {
 
-void ValidateInstancesChain(Isolate* isolate, Handle<JSObject> wasm_module,
+void ValidateInstancesChain(Isolate* isolate,
+                            Handle<WasmModuleObject> module_obj,
                             int instance_count);
-void ValidateModuleState(Isolate* isolate, Handle<JSObject> wasm_module);
-void ValidateOrphanedInstance(Isolate* isolate, Handle<JSObject> instance);
+void ValidateModuleState(Isolate* isolate, Handle<WasmModuleObject> module_obj);
+void ValidateOrphanedInstance(Isolate* isolate,
+                              Handle<WasmInstanceObject> instance);
 
 }  // namespace testing
 }  // namespace wasm
diff --git a/deps/v8/src/wasm/wasm-objects.cc b/deps/v8/src/wasm/wasm-objects.cc
index 68f66d246d..3f694c579f 100644
--- a/deps/v8/src/wasm/wasm-objects.cc
+++ b/deps/v8/src/wasm/wasm-objects.cc
@@ -3,7 +3,12 @@
 // found in the LICENSE file.
 
 #include "src/wasm/wasm-objects.h"
+#include "src/utils.h"
+
+#include "src/debug/debug-interface.h"
+#include "src/wasm/module-decoder.h"
 #include "src/wasm/wasm-module.h"
+#include "src/wasm/wasm-text.h"
 
 #define TRACE(...)                                      \
   do {                                                  \
@@ -18,29 +23,38 @@
 using namespace v8::internal;
 using namespace v8::internal::wasm;
 
-#define DEFINE_ACCESSORS(Container, name, field, type) \
-  type* Container::get_##name() {                      \
-    return type::cast(GetInternalField(field));        \
-  }                                                    \
-  void Container::set_##name(type* value) {            \
-    return SetInternalField(field, value);             \
-  }
+#define DEFINE_GETTER0(getter, Container, name, field, type) \
+  type* Container::name() { return type::cast(getter(field)); }
 
-#define DEFINE_OPTIONAL_ACCESSORS(Container, name, field, type) \
-  bool Container::has_##name() {                                \
-    return !GetInternalField(field)->IsUndefined(GetIsolate()); \
-  }                                                             \
-  type* Container::get_##name() {                               \
-    return type::cast(GetInternalField(field));                 \
-  }                                                             \
-  void Container::set_##name(type* value) {                     \
-    return SetInternalField(field, value);                      \
-  }
+#define DEFINE_ACCESSORS0(getter, setter, Container, name, field, type) \
+  DEFINE_GETTER0(getter, Container, name, field, type)                  \
+  void Container::set_##name(type* value) { return setter(field, value); }
 
-#define DEFINE_GETTER(Container, name, field, type) \
-  type* Container::get_##name() { return type::cast(GetInternalField(field)); }
+#define DEFINE_OPTIONAL_ACCESSORS0(getter, setter, Container, name, field, \
+                                   type)                                   \
+  DEFINE_ACCESSORS0(getter, setter, Container, name, field, type)          \
+  bool Container::has_##name() {                                           \
+    return !getter(field)->IsUndefined(GetIsolate());                      \
+  }
 
-static uint32_t SafeUint32(Object* value) {
+#define DEFINE_OBJ_GETTER(Container, name, field, type) \
+  DEFINE_GETTER0(GetInternalField, Container, name, field, type)
+#define DEFINE_OBJ_ACCESSORS(Container, name, field, type)               \
+  DEFINE_ACCESSORS0(GetInternalField, SetInternalField, Container, name, \
+                    field, type)
+#define DEFINE_OPTIONAL_OBJ_ACCESSORS(Container, name, field, type)         \
+  DEFINE_OPTIONAL_ACCESSORS0(GetInternalField, SetInternalField, Container, \
+                             name, field, type)
+#define DEFINE_ARR_GETTER(Container, name, field, type) \
+  DEFINE_GETTER0(get, Container, name, field, type)
+#define DEFINE_ARR_ACCESSORS(Container, name, field, type) \
+  DEFINE_ACCESSORS0(get, set, Container, name, field, type)
+#define DEFINE_OPTIONAL_ARR_ACCESSORS(Container, name, field, type) \
+  DEFINE_OPTIONAL_ACCESSORS0(get, set, Container, name, field, type)
+
+namespace {
+
+uint32_t SafeUint32(Object* value) {
   if (value->IsSmi()) {
     int32_t val = Smi::cast(value)->value();
     CHECK_GE(val, 0);
@@ -49,21 +63,23 @@ static uint32_t SafeUint32(Object* value) {
   DCHECK(value->IsHeapNumber());
   HeapNumber* num = HeapNumber::cast(value);
   CHECK_GE(num->value(), 0.0);
-  CHECK_LE(num->value(), static_cast<double>(kMaxUInt32));
+  CHECK_LE(num->value(), kMaxUInt32);
   return static_cast<uint32_t>(num->value());
 }
 
-static int32_t SafeInt32(Object* value) {
+int32_t SafeInt32(Object* value) {
   if (value->IsSmi()) {
     return Smi::cast(value)->value();
   }
   DCHECK(value->IsHeapNumber());
   HeapNumber* num = HeapNumber::cast(value);
-  CHECK_GE(num->value(), static_cast<double>(Smi::kMinValue));
-  CHECK_LE(num->value(), static_cast<double>(Smi::kMaxValue));
+  CHECK_GE(num->value(), Smi::kMinValue);
+  CHECK_LE(num->value(), Smi::kMaxValue);
   return static_cast<int32_t>(num->value());
 }
 
+}  // namespace
+
 Handle<WasmModuleObject> WasmModuleObject::New(
     Isolate* isolate, Handle<WasmCompiledModule> compiled_module) {
   ModuleOrigin origin = compiled_module->module()->origin;
@@ -97,8 +113,16 @@ WasmModuleObject* WasmModuleObject::cast(Object* object) {
   return reinterpret_cast<WasmModuleObject*>(object);
 }
 
+bool WasmModuleObject::IsWasmModuleObject(Object* object) {
+  return object->IsJSObject() &&
+         JSObject::cast(object)->GetInternalFieldCount() == kFieldCount;
+}
+
+DEFINE_OBJ_GETTER(WasmModuleObject, compiled_module, kCompiledModule,
+                  WasmCompiledModule)
+
 Handle<WasmTableObject> WasmTableObject::New(Isolate* isolate, uint32_t initial,
-                                             uint32_t maximum,
+                                             int64_t maximum,
                                              Handle<FixedArray>* js_functions) {
   Handle<JSFunction> table_ctor(
       isolate->native_context()->wasm_table_constructor());
@@ -109,8 +133,8 @@ Handle<WasmTableObject> WasmTableObject::New(Isolate* isolate, uint32_t initial,
     (*js_functions)->set(i, null);
   }
   table_obj->SetInternalField(kFunctions, *(*js_functions));
-  table_obj->SetInternalField(kMaximum,
-                              static_cast<Object*>(Smi::FromInt(maximum)));
+  Handle<Object> max = isolate->factory()->NewNumber(maximum);
+  table_obj->SetInternalField(kMaximum, *max);
 
   Handle<FixedArray> dispatch_tables = isolate->factory()->NewFixedArray(0);
   table_obj->SetInternalField(kDispatchTables, *dispatch_tables);
@@ -119,27 +143,28 @@ Handle<WasmTableObject> WasmTableObject::New(Isolate* isolate, uint32_t initial,
   return Handle<WasmTableObject>::cast(table_obj);
 }
 
-DEFINE_GETTER(WasmTableObject, dispatch_tables, kDispatchTables, FixedArray)
+DEFINE_OBJ_GETTER(WasmTableObject, dispatch_tables, kDispatchTables, FixedArray)
 
 Handle<FixedArray> WasmTableObject::AddDispatchTable(
     Isolate* isolate, Handle<WasmTableObject> table_obj,
     Handle<WasmInstanceObject> instance, int table_index,
-    Handle<FixedArray> dispatch_table) {
+    Handle<FixedArray> function_table, Handle<FixedArray> signature_table) {
   Handle<FixedArray> dispatch_tables(
       FixedArray::cast(table_obj->GetInternalField(kDispatchTables)), isolate);
-  DCHECK_EQ(0, dispatch_tables->length() % 3);
+  DCHECK_EQ(0, dispatch_tables->length() % 4);
 
   if (instance.is_null()) return dispatch_tables;
   // TODO(titzer): use weak cells here to avoid leaking instances.
 
   // Grow the dispatch table and add a new triple at the end.
   Handle<FixedArray> new_dispatch_tables =
-      isolate->factory()->CopyFixedArrayAndGrow(dispatch_tables, 3);
+      isolate->factory()->CopyFixedArrayAndGrow(dispatch_tables, 4);
 
   new_dispatch_tables->set(dispatch_tables->length() + 0, *instance);
   new_dispatch_tables->set(dispatch_tables->length() + 1,
                            Smi::FromInt(table_index));
-  new_dispatch_tables->set(dispatch_tables->length() + 2, *dispatch_table);
+  new_dispatch_tables->set(dispatch_tables->length() + 2, *function_table);
+  new_dispatch_tables->set(dispatch_tables->length() + 3, *signature_table);
 
   table_obj->SetInternalField(WasmTableObject::kDispatchTables,
                               *new_dispatch_tables);
@@ -147,12 +172,16 @@ Handle<FixedArray> WasmTableObject::AddDispatchTable(
   return new_dispatch_tables;
 }
 
-DEFINE_ACCESSORS(WasmTableObject, functions, kFunctions, FixedArray)
+DEFINE_OBJ_ACCESSORS(WasmTableObject, functions, kFunctions, FixedArray)
+
+uint32_t WasmTableObject::current_length() { return functions()->length(); }
 
-uint32_t WasmTableObject::current_length() { return get_functions()->length(); }
+bool WasmTableObject::has_maximum_length() {
+  return GetInternalField(kMaximum)->Number() >= 0;
+}
 
-uint32_t WasmTableObject::maximum_length() {
-  return SafeUint32(GetInternalField(kMaximum));
+int64_t WasmTableObject::maximum_length() {
+  return static_cast<int64_t>(GetInternalField(kMaximum)->Number());
 }
 
 WasmTableObject* WasmTableObject::cast(Object* object) {
@@ -161,28 +190,42 @@ WasmTableObject* WasmTableObject::cast(Object* object) {
   return reinterpret_cast<WasmTableObject*>(object);
 }
 
+void WasmTableObject::Grow(Isolate* isolate, Handle<WasmTableObject> table,
+                           uint32_t count) {
+  Handle<FixedArray> dispatch_tables(table->dispatch_tables());
+  wasm::GrowDispatchTables(isolate, dispatch_tables,
+                           table->functions()->length(), count);
+}
+
 Handle<WasmMemoryObject> WasmMemoryObject::New(Isolate* isolate,
                                                Handle<JSArrayBuffer> buffer,
-                                               int maximum) {
+                                               int32_t maximum) {
   Handle<JSFunction> memory_ctor(
       isolate->native_context()->wasm_memory_constructor());
-  Handle<JSObject> memory_obj = isolate->factory()->NewJSObject(memory_ctor);
+  Handle<JSObject> memory_obj =
+      isolate->factory()->NewJSObject(memory_ctor, TENURED);
   memory_obj->SetInternalField(kArrayBuffer, *buffer);
-  memory_obj->SetInternalField(kMaximum,
-                               static_cast<Object*>(Smi::FromInt(maximum)));
+  Handle<Object> max = isolate->factory()->NewNumber(maximum);
+  memory_obj->SetInternalField(kMaximum, *max);
   Handle<Symbol> memory_sym(isolate->native_context()->wasm_memory_sym());
   Object::SetProperty(memory_obj, memory_sym, memory_obj, STRICT).Check();
   return Handle<WasmMemoryObject>::cast(memory_obj);
 }
 
-DEFINE_ACCESSORS(WasmMemoryObject, buffer, kArrayBuffer, JSArrayBuffer)
+DEFINE_OBJ_ACCESSORS(WasmMemoryObject, buffer, kArrayBuffer, JSArrayBuffer)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmMemoryObject, instances_link, kInstancesLink,
+                              WasmInstanceWrapper)
 
 uint32_t WasmMemoryObject::current_pages() {
-  return SafeUint32(get_buffer()->byte_length()) / wasm::WasmModule::kPageSize;
+  return SafeUint32(buffer()->byte_length()) / wasm::WasmModule::kPageSize;
+}
+
+bool WasmMemoryObject::has_maximum_pages() {
+  return GetInternalField(kMaximum)->Number() >= 0;
 }
 
 int32_t WasmMemoryObject::maximum_pages() {
-  return SafeInt32(GetInternalField(kMaximum));
+  return static_cast<int32_t>(GetInternalField(kMaximum)->Number());
 }
 
 WasmMemoryObject* WasmMemoryObject::cast(Object* object) {
@@ -191,31 +234,50 @@ WasmMemoryObject* WasmMemoryObject::cast(Object* object) {
   return reinterpret_cast<WasmMemoryObject*>(object);
 }
 
-void WasmMemoryObject::AddInstance(WasmInstanceObject* instance) {
-  // TODO(gdeepti): This should be a weak list of instance objects
-  // for instances that share memory.
-  SetInternalField(kInstance, instance);
+void WasmMemoryObject::AddInstance(Isolate* isolate,
+                                   Handle<WasmInstanceObject> instance) {
+  Handle<WasmInstanceWrapper> instance_wrapper =
+      handle(instance->instance_wrapper());
+  if (has_instances_link()) {
+    Handle<WasmInstanceWrapper> current_wrapper(instances_link());
+    DCHECK(WasmInstanceWrapper::IsWasmInstanceWrapper(*current_wrapper));
+    DCHECK(!current_wrapper->has_previous());
+    instance_wrapper->set_next_wrapper(*current_wrapper);
+    current_wrapper->set_previous_wrapper(*instance_wrapper);
+  }
+  set_instances_link(*instance_wrapper);
+}
+
+void WasmMemoryObject::ResetInstancesLink(Isolate* isolate) {
+  Handle<Object> undefined = isolate->factory()->undefined_value();
+  SetInternalField(kInstancesLink, *undefined);
 }
 
-DEFINE_ACCESSORS(WasmInstanceObject, compiled_module, kCompiledModule,
-                 WasmCompiledModule)
-DEFINE_OPTIONAL_ACCESSORS(WasmInstanceObject, globals_buffer,
-                          kGlobalsArrayBuffer, JSArrayBuffer)
-DEFINE_OPTIONAL_ACCESSORS(WasmInstanceObject, memory_buffer, kMemoryArrayBuffer,
-                          JSArrayBuffer)
-DEFINE_OPTIONAL_ACCESSORS(WasmInstanceObject, memory_object, kMemoryObject,
-                          WasmMemoryObject)
-DEFINE_OPTIONAL_ACCESSORS(WasmInstanceObject, debug_info, kDebugInfo,
-                          WasmDebugInfo)
+DEFINE_OBJ_ACCESSORS(WasmInstanceObject, compiled_module, kCompiledModule,
+                     WasmCompiledModule)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmInstanceObject, globals_buffer,
+                              kGlobalsArrayBuffer, JSArrayBuffer)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmInstanceObject, memory_buffer,
+                              kMemoryArrayBuffer, JSArrayBuffer)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmInstanceObject, memory_object, kMemoryObject,
+                              WasmMemoryObject)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmInstanceObject, debug_info, kDebugInfo,
+                              WasmDebugInfo)
+DEFINE_OPTIONAL_OBJ_ACCESSORS(WasmInstanceObject, instance_wrapper,
+                              kWasmMemInstanceWrapper, WasmInstanceWrapper)
 
 WasmModuleObject* WasmInstanceObject::module_object() {
-  return WasmModuleObject::cast(*get_compiled_module()->wasm_module());
+  return *compiled_module()->wasm_module();
 }
 
-WasmModule* WasmInstanceObject::module() {
-  return reinterpret_cast<WasmModuleWrapper*>(
-             *get_compiled_module()->module_wrapper())
-      ->get();
+WasmModule* WasmInstanceObject::module() { return compiled_module()->module(); }
+
+Handle<WasmDebugInfo> WasmInstanceObject::GetOrCreateDebugInfo(
+    Handle<WasmInstanceObject> instance) {
+  if (instance->has_debug_info()) return handle(instance->debug_info());
+  Handle<WasmDebugInfo> new_info = WasmDebugInfo::New(instance);
+  instance->set_debug_info(*new_info);
+  return new_info;
 }
 
 WasmInstanceObject* WasmInstanceObject::cast(Object* object) {
@@ -224,7 +286,6 @@ WasmInstanceObject* WasmInstanceObject::cast(Object* object) {
 }
 
 bool WasmInstanceObject::IsWasmInstanceObject(Object* object) {
-  if (!object->IsObject()) return false;
   if (!object->IsJSObject()) return false;
 
   JSObject* obj = JSObject::cast(object);
@@ -246,15 +307,21 @@ bool WasmInstanceObject::IsWasmInstanceObject(Object* object) {
 
 Handle<WasmInstanceObject> WasmInstanceObject::New(
     Isolate* isolate, Handle<WasmCompiledModule> compiled_module) {
-  Handle<Map> map = isolate->factory()->NewMap(
-      JS_OBJECT_TYPE, JSObject::kHeaderSize + kFieldCount * kPointerSize);
+  Handle<JSFunction> instance_cons(
+      isolate->native_context()->wasm_instance_constructor());
+  Handle<JSObject> instance_object =
+      isolate->factory()->NewJSObject(instance_cons, TENURED);
+  Handle<Symbol> instance_sym(isolate->native_context()->wasm_instance_sym());
+  Object::SetProperty(instance_object, instance_sym, instance_object, STRICT)
+      .Check();
   Handle<WasmInstanceObject> instance(
-      reinterpret_cast<WasmInstanceObject*>(
-          *isolate->factory()->NewJSObjectFromMap(map, TENURED)),
-      isolate);
+      reinterpret_cast<WasmInstanceObject*>(*instance_object), isolate);
 
   instance->SetInternalField(kCompiledModule, *compiled_module);
   instance->SetInternalField(kMemoryObject, isolate->heap()->undefined_value());
+  Handle<WasmInstanceWrapper> instance_wrapper =
+      WasmInstanceWrapper::New(isolate, instance);
+  instance->SetInternalField(kWasmMemInstanceWrapper, *instance_wrapper);
   return instance;
 }
 
@@ -275,8 +342,20 @@ WasmExportedFunction* WasmExportedFunction::cast(Object* object) {
 }
 
 Handle<WasmExportedFunction> WasmExportedFunction::New(
-    Isolate* isolate, Handle<WasmInstanceObject> instance, Handle<String> name,
-    Handle<Code> export_wrapper, int arity, int func_index) {
+    Isolate* isolate, Handle<WasmInstanceObject> instance,
+    MaybeHandle<String> maybe_name, int func_index, int arity,
+    Handle<Code> export_wrapper) {
+  Handle<String> name;
+  if (maybe_name.is_null()) {
+    EmbeddedVector<char, 16> buffer;
+    int length = SNPrintF(buffer, "%d", func_index);
+    name = isolate->factory()
+               ->NewStringFromAscii(
+                   Vector<const char>::cast(buffer.SubVector(0, length)))
+               .ToHandleChecked();
+  } else {
+    name = maybe_name.ToHandleChecked();
+  }
   DCHECK_EQ(Code::JS_TO_WASM_FUNCTION, export_wrapper->kind());
   Handle<SharedFunctionInfo> shared =
       isolate->factory()->NewSharedFunctionInfo(name, export_wrapper, false);
@@ -291,22 +370,109 @@ Handle<WasmExportedFunction> WasmExportedFunction::New(
   return Handle<WasmExportedFunction>::cast(function);
 }
 
+bool WasmSharedModuleData::IsWasmSharedModuleData(Object* object) {
+  if (!object->IsFixedArray()) return false;
+  FixedArray* arr = FixedArray::cast(object);
+  if (arr->length() != kFieldCount) return false;
+  Isolate* isolate = arr->GetIsolate();
+  if (!arr->get(kModuleWrapper)->IsForeign()) return false;
+  if (!arr->get(kModuleBytes)->IsUndefined(isolate) &&
+      !arr->get(kModuleBytes)->IsSeqOneByteString())
+    return false;
+  if (!arr->get(kScript)->IsScript()) return false;
+  if (!arr->get(kAsmJsOffsetTable)->IsUndefined(isolate) &&
+      !arr->get(kAsmJsOffsetTable)->IsByteArray())
+    return false;
+  return true;
+}
+
+WasmSharedModuleData* WasmSharedModuleData::cast(Object* object) {
+  DCHECK(IsWasmSharedModuleData(object));
+  return reinterpret_cast<WasmSharedModuleData*>(object);
+}
+
+wasm::WasmModule* WasmSharedModuleData::module() {
+  return reinterpret_cast<WasmModuleWrapper*>(get(kModuleWrapper))->get();
+}
+
+DEFINE_OPTIONAL_ARR_ACCESSORS(WasmSharedModuleData, module_bytes, kModuleBytes,
+                              SeqOneByteString);
+DEFINE_ARR_GETTER(WasmSharedModuleData, script, kScript, Script);
+DEFINE_OPTIONAL_ARR_ACCESSORS(WasmSharedModuleData, asm_js_offset_table,
+                              kAsmJsOffsetTable, ByteArray);
+
+Handle<WasmSharedModuleData> WasmSharedModuleData::New(
+    Isolate* isolate, Handle<Foreign> module_wrapper,
+    Handle<SeqOneByteString> module_bytes, Handle<Script> script,
+    Handle<ByteArray> asm_js_offset_table) {
+  Handle<FixedArray> arr =
+      isolate->factory()->NewFixedArray(kFieldCount, TENURED);
+
+  arr->set(kModuleWrapper, *module_wrapper);
+  if (!module_bytes.is_null()) {
+    arr->set(kModuleBytes, *module_bytes);
+  }
+  if (!script.is_null()) {
+    arr->set(kScript, *script);
+  }
+  if (!asm_js_offset_table.is_null()) {
+    arr->set(kAsmJsOffsetTable, *asm_js_offset_table);
+  }
+
+  DCHECK(WasmSharedModuleData::IsWasmSharedModuleData(*arr));
+  return Handle<WasmSharedModuleData>::cast(arr);
+}
+
+bool WasmSharedModuleData::is_asm_js() {
+  bool asm_js = module()->origin == wasm::ModuleOrigin::kAsmJsOrigin;
+  DCHECK_EQ(asm_js, script()->type() == Script::TYPE_NORMAL);
+  DCHECK_EQ(asm_js, has_asm_js_offset_table());
+  return asm_js;
+}
+
+void WasmSharedModuleData::RecreateModuleWrapper(
+    Isolate* isolate, Handle<WasmSharedModuleData> shared) {
+  DCHECK(shared->get(kModuleWrapper)->IsUndefined(isolate));
+
+  WasmModule* module = nullptr;
+  {
+    // We parse the module again directly from the module bytes, so
+    // the underlying storage must not be moved meanwhile.
+    DisallowHeapAllocation no_allocation;
+    SeqOneByteString* module_bytes = shared->module_bytes();
+    const byte* start =
+        reinterpret_cast<const byte*>(module_bytes->GetCharsAddress());
+    const byte* end = start + module_bytes->length();
+    // TODO(titzer): remember the module origin in the compiled_module
+    // For now, we assume serialized modules did not originate from asm.js.
+    ModuleResult result =
+        DecodeWasmModule(isolate, start, end, false, kWasmOrigin);
+    CHECK(result.ok());
+    CHECK_NOT_NULL(result.val);
+    module = const_cast<WasmModule*>(result.val);
+  }
+
+  Handle<WasmModuleWrapper> module_wrapper =
+      WasmModuleWrapper::New(isolate, module);
+
+  shared->set(kModuleWrapper, *module_wrapper);
+  DCHECK(WasmSharedModuleData::IsWasmSharedModuleData(*shared));
+}
+
 Handle<WasmCompiledModule> WasmCompiledModule::New(
-    Isolate* isolate, Handle<WasmModuleWrapper> module_wrapper) {
+    Isolate* isolate, Handle<WasmSharedModuleData> shared) {
   Handle<FixedArray> ret =
       isolate->factory()->NewFixedArray(PropertyIndices::Count, TENURED);
-  // WasmCompiledModule::cast would fail since module bytes are not set yet.
+  // WasmCompiledModule::cast would fail since fields are not set yet.
   Handle<WasmCompiledModule> compiled_module(
       reinterpret_cast<WasmCompiledModule*>(*ret), isolate);
   compiled_module->InitId();
-  compiled_module->set_module_wrapper(module_wrapper);
+  compiled_module->set_num_imported_functions(0);
+  compiled_module->set_shared(shared);
+  compiled_module->set_native_context(isolate->native_context());
   return compiled_module;
 }
 
-wasm::WasmModule* WasmCompiledModule::module() const {
-  return reinterpret_cast<WasmModuleWrapper*>(*module_wrapper())->get();
-}
-
 void WasmCompiledModule::InitId() {
 #if DEBUG
   static uint32_t instance_id_counter = 0;
@@ -315,19 +481,39 @@ void WasmCompiledModule::InitId() {
 #endif
 }
 
+MaybeHandle<String> WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+    Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+    uint32_t offset, uint32_t size) {
+  // TODO(wasm): cache strings from modules if it's a performance win.
+  Handle<SeqOneByteString> module_bytes(compiled_module->module_bytes(),
+                                        isolate);
+  DCHECK_GE(module_bytes->length(), offset);
+  DCHECK_GE(module_bytes->length() - offset, size);
+  Address raw = module_bytes->GetCharsAddress() + offset;
+  if (!unibrow::Utf8::Validate(reinterpret_cast<const byte*>(raw), size))
+    return {};  // UTF8 decoding error for name.
+  DCHECK_GE(kMaxInt, offset);
+  DCHECK_GE(kMaxInt, size);
+  return isolate->factory()->NewStringFromUtf8SubString(
+      module_bytes, static_cast<int>(offset), static_cast<int>(size));
+}
+
 bool WasmCompiledModule::IsWasmCompiledModule(Object* obj) {
   if (!obj->IsFixedArray()) return false;
   FixedArray* arr = FixedArray::cast(obj);
   if (arr->length() != PropertyIndices::Count) return false;
   Isolate* isolate = arr->GetIsolate();
-#define WCM_CHECK_SMALL_NUMBER(TYPE, NAME) \
-  if (!arr->get(kID_##NAME)->IsSmi()) return false;
-#define WCM_CHECK_OBJECT_OR_WEAK(TYPE, NAME)         \
-  if (!arr->get(kID_##NAME)->IsUndefined(isolate) && \
-      !arr->get(kID_##NAME)->Is##TYPE())             \
-    return false;
-#define WCM_CHECK_OBJECT(TYPE, NAME) WCM_CHECK_OBJECT_OR_WEAK(TYPE, NAME)
-#define WCM_CHECK_WEAK_LINK(TYPE, NAME) WCM_CHECK_OBJECT_OR_WEAK(WeakCell, NAME)
+#define WCM_CHECK_TYPE(NAME, TYPE_CHECK) \
+  do {                                   \
+    Object* obj = arr->get(kID_##NAME);  \
+    if (!(TYPE_CHECK)) return false;     \
+  } while (false);
+#define WCM_CHECK_OBJECT(TYPE, NAME) \
+  WCM_CHECK_TYPE(NAME, obj->IsUndefined(isolate) || obj->Is##TYPE())
+#define WCM_CHECK_WASM_OBJECT(TYPE, NAME) \
+  WCM_CHECK_TYPE(NAME, TYPE::Is##TYPE(obj))
+#define WCM_CHECK_WEAK_LINK(TYPE, NAME) WCM_CHECK_OBJECT(WeakCell, NAME)
+#define WCM_CHECK_SMALL_NUMBER(TYPE, NAME) WCM_CHECK_TYPE(NAME, obj->IsSmi())
 #define WCM_CHECK(KIND, TYPE, NAME) WCM_CHECK_##KIND(TYPE, NAME)
   WCM_PROPERTY_TABLE(WCM_CHECK)
 #undef WCM_CHECK
@@ -341,7 +527,7 @@ void WasmCompiledModule::PrintInstancesChain() {
   if (!FLAG_trace_wasm_instances) return;
   for (WasmCompiledModule* current = this; current != nullptr;) {
     PrintF("->%d", current->instance_id());
-    if (current->ptr_to_weak_next_instance() == nullptr) break;
+    if (!current->has_weak_next_instance()) break;
     CHECK(!current->ptr_to_weak_next_instance()->cleared());
     current =
         WasmCompiledModule::cast(current->ptr_to_weak_next_instance()->value());
@@ -350,6 +536,19 @@ void WasmCompiledModule::PrintInstancesChain() {
 #endif
 }
 
+void WasmCompiledModule::RecreateModuleWrapper(
+    Isolate* isolate, Handle<WasmCompiledModule> compiled_module) {
+  // This method must only be called immediately after deserialization.
+  // At this point, no module wrapper exists, so the shared module data is
+  // incomplete.
+  Handle<WasmSharedModuleData> shared(
+      static_cast<WasmSharedModuleData*>(compiled_module->get(kID_shared)),
+      isolate);
+  DCHECK(!WasmSharedModuleData::IsWasmSharedModuleData(*shared));
+  WasmSharedModuleData::RecreateModuleWrapper(isolate, shared);
+  DCHECK(WasmSharedModuleData::IsWasmSharedModuleData(*shared));
+}
+
 uint32_t WasmCompiledModule::mem_size() const {
   return has_memory() ? memory()->byte_length()->Number() : default_mem_size();
 }
@@ -357,3 +556,310 @@ uint32_t WasmCompiledModule::mem_size() const {
 uint32_t WasmCompiledModule::default_mem_size() const {
   return min_mem_pages() * WasmModule::kPageSize;
 }
+
+MaybeHandle<String> WasmCompiledModule::GetFunctionNameOrNull(
+    Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+    uint32_t func_index) {
+  DCHECK_LT(func_index, compiled_module->module()->functions.size());
+  WasmFunction& function = compiled_module->module()->functions[func_index];
+  return WasmCompiledModule::ExtractUtf8StringFromModuleBytes(
+      isolate, compiled_module, function.name_offset, function.name_length);
+}
+
+Handle<String> WasmCompiledModule::GetFunctionName(
+    Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+    uint32_t func_index) {
+  MaybeHandle<String> name =
+      GetFunctionNameOrNull(isolate, compiled_module, func_index);
+  if (!name.is_null()) return name.ToHandleChecked();
+  return isolate->factory()->NewStringFromStaticChars("<WASM UNNAMED>");
+}
+
+Vector<const uint8_t> WasmCompiledModule::GetRawFunctionName(
+    uint32_t func_index) {
+  DCHECK_GT(module()->functions.size(), func_index);
+  WasmFunction& function = module()->functions[func_index];
+  SeqOneByteString* bytes = module_bytes();
+  DCHECK_GE(bytes->length(), function.name_offset);
+  DCHECK_GE(bytes->length() - function.name_offset, function.name_length);
+  return Vector<const uint8_t>(bytes->GetCharsAddress() + function.name_offset,
+                               function.name_length);
+}
+
+int WasmCompiledModule::GetFunctionOffset(uint32_t func_index) {
+  std::vector<WasmFunction>& functions = module()->functions;
+  if (static_cast<uint32_t>(func_index) >= functions.size()) return -1;
+  DCHECK_GE(kMaxInt, functions[func_index].code_start_offset);
+  return static_cast<int>(functions[func_index].code_start_offset);
+}
+
+int WasmCompiledModule::GetContainingFunction(uint32_t byte_offset) {
+  std::vector<WasmFunction>& functions = module()->functions;
+
+  // Binary search for a function containing the given position.
+  int left = 0;                                    // inclusive
+  int right = static_cast<int>(functions.size());  // exclusive
+  if (right == 0) return false;
+  while (right - left > 1) {
+    int mid = left + (right - left) / 2;
+    if (functions[mid].code_start_offset <= byte_offset) {
+      left = mid;
+    } else {
+      right = mid;
+    }
+  }
+  // If the found function does not contains the given position, return -1.
+  WasmFunction& func = functions[left];
+  if (byte_offset < func.code_start_offset ||
+      byte_offset >= func.code_end_offset) {
+    return -1;
+  }
+
+  return left;
+}
+
+bool WasmCompiledModule::GetPositionInfo(uint32_t position,
+                                         Script::PositionInfo* info) {
+  int func_index = GetContainingFunction(position);
+  if (func_index < 0) return false;
+
+  WasmFunction& function = module()->functions[func_index];
+
+  info->line = func_index;
+  info->column = position - function.code_start_offset;
+  info->line_start = function.code_start_offset;
+  info->line_end = function.code_end_offset;
+  return true;
+}
+
+namespace {
+
+enum AsmJsOffsetTableEntryLayout {
+  kOTEByteOffset,
+  kOTECallPosition,
+  kOTENumberConvPosition,
+  kOTESize
+};
+
+Handle<ByteArray> GetDecodedAsmJsOffsetTable(
+    Handle<WasmCompiledModule> compiled_module, Isolate* isolate) {
+  DCHECK(compiled_module->is_asm_js());
+  Handle<ByteArray> offset_table(
+      compiled_module->shared()->asm_js_offset_table(), isolate);
+
+  // The last byte in the asm_js_offset_tables ByteArray tells whether it is
+  // still encoded (0) or decoded (1).
+  enum AsmJsTableType : int { Encoded = 0, Decoded = 1 };
+  int table_type = offset_table->get(offset_table->length() - 1);
+  DCHECK(table_type == Encoded || table_type == Decoded);
+  if (table_type == Decoded) return offset_table;
+
+  AsmJsOffsetsResult asm_offsets;
+  {
+    DisallowHeapAllocation no_gc;
+    const byte* bytes_start = offset_table->GetDataStartAddress();
+    const byte* bytes_end = bytes_start + offset_table->length() - 1;
+    asm_offsets = wasm::DecodeAsmJsOffsets(bytes_start, bytes_end);
+  }
+  // Wasm bytes must be valid and must contain asm.js offset table.
+  DCHECK(asm_offsets.ok());
+  DCHECK_GE(kMaxInt, asm_offsets.val.size());
+  int num_functions = static_cast<int>(asm_offsets.val.size());
+  int num_imported_functions =
+      static_cast<int>(compiled_module->module()->num_imported_functions);
+  DCHECK_EQ(compiled_module->module()->functions.size(),
+            static_cast<size_t>(num_functions) + num_imported_functions);
+  int num_entries = 0;
+  for (int func = 0; func < num_functions; ++func) {
+    size_t new_size = asm_offsets.val[func].size();
+    DCHECK_LE(new_size, static_cast<size_t>(kMaxInt) - num_entries);
+    num_entries += static_cast<int>(new_size);
+  }
+  // One byte to encode that this is a decoded table.
+  DCHECK_GE(kMaxInt,
+            1 + static_cast<uint64_t>(num_entries) * kOTESize * kIntSize);
+  int total_size = 1 + num_entries * kOTESize * kIntSize;
+  Handle<ByteArray> decoded_table =
+      isolate->factory()->NewByteArray(total_size, TENURED);
+  decoded_table->set(total_size - 1, AsmJsTableType::Decoded);
+  compiled_module->shared()->set_asm_js_offset_table(*decoded_table);
+
+  int idx = 0;
+  std::vector<WasmFunction>& wasm_funs = compiled_module->module()->functions;
+  for (int func = 0; func < num_functions; ++func) {
+    std::vector<AsmJsOffsetEntry>& func_asm_offsets = asm_offsets.val[func];
+    if (func_asm_offsets.empty()) continue;
+    int func_offset =
+        wasm_funs[num_imported_functions + func].code_start_offset;
+    for (AsmJsOffsetEntry& e : func_asm_offsets) {
+      // Byte offsets must be strictly monotonously increasing:
+      DCHECK_IMPLIES(idx > 0, func_offset + e.byte_offset >
+                                  decoded_table->get_int(idx - kOTESize));
+      decoded_table->set_int(idx + kOTEByteOffset, func_offset + e.byte_offset);
+      decoded_table->set_int(idx + kOTECallPosition, e.source_position_call);
+      decoded_table->set_int(idx + kOTENumberConvPosition,
+                             e.source_position_number_conversion);
+      idx += kOTESize;
+    }
+  }
+  DCHECK_EQ(total_size, idx * kIntSize + 1);
+  return decoded_table;
+}
+
+}  // namespace
+
+int WasmCompiledModule::GetAsmJsSourcePosition(
+    Handle<WasmCompiledModule> compiled_module, uint32_t func_index,
+    uint32_t byte_offset, bool is_at_number_conversion) {
+  Isolate* isolate = compiled_module->GetIsolate();
+  Handle<ByteArray> offset_table =
+      GetDecodedAsmJsOffsetTable(compiled_module, isolate);
+
+  DCHECK_LT(func_index, compiled_module->module()->functions.size());
+  uint32_t func_code_offset =
+      compiled_module->module()->functions[func_index].code_start_offset;
+  uint32_t total_offset = func_code_offset + byte_offset;
+
+  // Binary search for the total byte offset.
+  int left = 0;                                              // inclusive
+  int right = offset_table->length() / kIntSize / kOTESize;  // exclusive
+  DCHECK_LT(left, right);
+  while (right - left > 1) {
+    int mid = left + (right - left) / 2;
+    int mid_entry = offset_table->get_int(kOTESize * mid);
+    DCHECK_GE(kMaxInt, mid_entry);
+    if (static_cast<uint32_t>(mid_entry) <= total_offset) {
+      left = mid;
+    } else {
+      right = mid;
+    }
+  }
+  // There should be an entry for each position that could show up on the stack
+  // trace:
+  DCHECK_EQ(total_offset, offset_table->get_int(kOTESize * left));
+  int idx = is_at_number_conversion ? kOTENumberConvPosition : kOTECallPosition;
+  return offset_table->get_int(kOTESize * left + idx);
+}
+
+v8::debug::WasmDisassembly WasmCompiledModule::DisassembleFunction(
+    int func_index) {
+  DisallowHeapAllocation no_gc;
+
+  if (func_index < 0 ||
+      static_cast<uint32_t>(func_index) >= module()->functions.size())
+    return {};
+
+  SeqOneByteString* module_bytes_str = module_bytes();
+  Vector<const byte> module_bytes(module_bytes_str->GetChars(),
+                                  module_bytes_str->length());
+
+  std::ostringstream disassembly_os;
+  v8::debug::WasmDisassembly::OffsetTable offset_table;
+
+  PrintWasmText(module(), module_bytes, static_cast<uint32_t>(func_index),
+                disassembly_os, &offset_table);
+
+  return {disassembly_os.str(), std::move(offset_table)};
+}
+
+bool WasmCompiledModule::GetPossibleBreakpoints(
+    const v8::debug::Location& start, const v8::debug::Location& end,
+    std::vector<v8::debug::Location>* locations) {
+  DisallowHeapAllocation no_gc;
+
+  std::vector<WasmFunction>& functions = module()->functions;
+  if (start.GetLineNumber() < 0 || start.GetColumnNumber() < 0 ||
+      (!end.IsEmpty() &&
+       (end.GetLineNumber() < 0 || end.GetColumnNumber() < 0)))
+    return false;
+
+  // start_func_index, start_offset and end_func_index is inclusive.
+  // end_offset is exclusive.
+  // start_offset and end_offset are module-relative byte offsets.
+  uint32_t start_func_index = start.GetLineNumber();
+  if (start_func_index >= functions.size()) return false;
+  int start_func_len = functions[start_func_index].code_end_offset -
+                       functions[start_func_index].code_start_offset;
+  if (start.GetColumnNumber() > start_func_len) return false;
+  uint32_t start_offset =
+      functions[start_func_index].code_start_offset + start.GetColumnNumber();
+  uint32_t end_func_index;
+  uint32_t end_offset;
+  if (end.IsEmpty()) {
+    // Default: everything till the end of the Script.
+    end_func_index = static_cast<uint32_t>(functions.size() - 1);
+    end_offset = functions[end_func_index].code_end_offset;
+  } else {
+    // If end is specified: Use it and check for valid input.
+    end_func_index = static_cast<uint32_t>(end.GetLineNumber());
+
+    // Special case: Stop before the start of the next function. Change to: Stop
+    // at the end of the function before, such that we don't disassemble the
+    // next function also.
+    if (end.GetColumnNumber() == 0 && end_func_index > 0) {
+      --end_func_index;
+      end_offset = functions[end_func_index].code_end_offset;
+    } else {
+      if (end_func_index >= functions.size()) return false;
+      end_offset =
+          functions[end_func_index].code_start_offset + end.GetColumnNumber();
+      if (end_offset > functions[end_func_index].code_end_offset) return false;
+    }
+  }
+
+  AccountingAllocator alloc;
+  Zone tmp(&alloc, ZONE_NAME);
+  const byte* module_start = module_bytes()->GetChars();
+
+  for (uint32_t func_idx = start_func_index; func_idx <= end_func_index;
+       ++func_idx) {
+    WasmFunction& func = functions[func_idx];
+    if (func.code_start_offset == func.code_end_offset) continue;
+
+    BodyLocalDecls locals(&tmp);
+    BytecodeIterator iterator(module_start + func.code_start_offset,
+                              module_start + func.code_end_offset, &locals);
+    DCHECK_LT(0u, locals.encoded_size);
+    for (uint32_t offset : iterator.offsets()) {
+      uint32_t total_offset = func.code_start_offset + offset;
+      if (total_offset >= end_offset) {
+        DCHECK_EQ(end_func_index, func_idx);
+        break;
+      }
+      if (total_offset < start_offset) continue;
+      locations->push_back(v8::debug::Location(func_idx, offset));
+    }
+  }
+  return true;
+}
+
+Handle<WasmInstanceWrapper> WasmInstanceWrapper::New(
+    Isolate* isolate, Handle<WasmInstanceObject> instance) {
+  Handle<FixedArray> array =
+      isolate->factory()->NewFixedArray(kWrapperPropertyCount, TENURED);
+  Handle<WasmInstanceWrapper> instance_wrapper(
+      reinterpret_cast<WasmInstanceWrapper*>(*array), isolate);
+  instance_wrapper->set_instance_object(instance, isolate);
+  return instance_wrapper;
+}
+
+bool WasmInstanceWrapper::IsWasmInstanceWrapper(Object* obj) {
+  if (!obj->IsFixedArray()) return false;
+  Handle<FixedArray> array = handle(FixedArray::cast(obj));
+  if (array->length() != kWrapperPropertyCount) return false;
+  if (!array->get(kWrapperInstanceObject)->IsWeakCell()) return false;
+  Isolate* isolate = array->GetIsolate();
+  if (!array->get(kNextInstanceWrapper)->IsUndefined(isolate) &&
+      !array->get(kNextInstanceWrapper)->IsFixedArray())
+    return false;
+  if (!array->get(kPreviousInstanceWrapper)->IsUndefined(isolate) &&
+      !array->get(kPreviousInstanceWrapper)->IsFixedArray())
+    return false;
+  return true;
+}
+
+void WasmInstanceWrapper::set_instance_object(Handle<JSObject> instance,
+                                              Isolate* isolate) {
+  Handle<WeakCell> cell = isolate->factory()->NewWeakCell(instance);
+  set(kWrapperInstanceObject, *cell);
+}
diff --git a/deps/v8/src/wasm/wasm-objects.h b/deps/v8/src/wasm/wasm-objects.h
index f74661f652..c478fe0419 100644
--- a/deps/v8/src/wasm/wasm-objects.h
+++ b/deps/v8/src/wasm/wasm-objects.h
@@ -5,8 +5,11 @@
 #ifndef V8_WASM_OBJECTS_H_
 #define V8_WASM_OBJECTS_H_
 
+#include "src/debug/interface-types.h"
 #include "src/objects-inl.h"
+#include "src/trap-handler/trap-handler.h"
 #include "src/wasm/managed.h"
+#include "src/wasm/wasm-limits.h"
 
 namespace v8 {
 namespace internal {
@@ -17,19 +20,21 @@ struct WasmModule;
 class WasmCompiledModule;
 class WasmDebugInfo;
 class WasmInstanceObject;
+class WasmInstanceWrapper;
 
 #define DECLARE_CASTS(name)             \
   static bool Is##name(Object* object); \
   static name* cast(Object* object)
 
+#define DECLARE_GETTER(name, type) type* name()
+
 #define DECLARE_ACCESSORS(name, type) \
-  type* get_##name();                 \
-  void set_##name(type* value)
+  void set_##name(type* value);       \
+  DECLARE_GETTER(name, type)
 
 #define DECLARE_OPTIONAL_ACCESSORS(name, type) \
   bool has_##name();                           \
-  type* get_##name();                          \
-  void set_##name(type* value)
+  DECLARE_ACCESSORS(name, type)
 
 // Representation of a WebAssembly.Module JavaScript-level object.
 class WasmModuleObject : public JSObject {
@@ -40,13 +45,6 @@ class WasmModuleObject : public JSObject {
   DECLARE_CASTS(WasmModuleObject);
 
   WasmCompiledModule* compiled_module();
-  wasm::WasmModule* module();
-  int num_functions();
-  bool is_asm_js();
-  int GetAsmWasmSourcePosition(int func_index, int byte_offset);
-  WasmDebugInfo* debug_info();
-  void set_debug_info(WasmDebugInfo* debug_info);
-  MaybeHandle<String> GetFunctionName(Isolate* isolate, int func_index);
 
   static Handle<WasmModuleObject> New(
       Isolate* isolate, Handle<WasmCompiledModule> compiled_module);
@@ -61,38 +59,44 @@ class WasmTableObject : public JSObject {
   DECLARE_CASTS(WasmTableObject);
   DECLARE_ACCESSORS(functions, FixedArray);
 
-  FixedArray* get_dispatch_tables();
+  FixedArray* dispatch_tables();
   uint32_t current_length();
-  uint32_t maximum_length();
+  bool has_maximum_length();
+  int64_t maximum_length();  // Returns < 0 if no maximum.
 
   static Handle<WasmTableObject> New(Isolate* isolate, uint32_t initial,
-                                     uint32_t maximum,
+                                     int64_t maximum,
                                      Handle<FixedArray>* js_functions);
-  static bool Grow(Handle<WasmTableObject> table, uint32_t count);
+  static void Grow(Isolate* isolate, Handle<WasmTableObject> table,
+                   uint32_t count);
   static Handle<FixedArray> AddDispatchTable(
       Isolate* isolate, Handle<WasmTableObject> table,
       Handle<WasmInstanceObject> instance, int table_index,
-      Handle<FixedArray> dispatch_table);
+      Handle<FixedArray> function_table, Handle<FixedArray> signature_table);
 };
 
 // Representation of a WebAssembly.Memory JavaScript-level object.
 class WasmMemoryObject : public JSObject {
  public:
   // TODO(titzer): add the brand as an internal field instead of a property.
-  enum Fields : uint8_t { kArrayBuffer, kMaximum, kInstance, kFieldCount };
+  enum Fields : uint8_t { kArrayBuffer, kMaximum, kInstancesLink, kFieldCount };
 
   DECLARE_CASTS(WasmMemoryObject);
   DECLARE_ACCESSORS(buffer, JSArrayBuffer);
+  DECLARE_OPTIONAL_ACCESSORS(instances_link, WasmInstanceWrapper);
 
-  void AddInstance(WasmInstanceObject* object);
+  void AddInstance(Isolate* isolate, Handle<WasmInstanceObject> object);
+  void ResetInstancesLink(Isolate* isolate);
   uint32_t current_pages();
-  int32_t maximum_pages();  // returns < 0 if there is no maximum
+  bool has_maximum_pages();
+  int32_t maximum_pages();  // Returns < 0 if there is no maximum.
 
   static Handle<WasmMemoryObject> New(Isolate* isolate,
                                       Handle<JSArrayBuffer> buffer,
-                                      int maximum);
+                                      int32_t maximum);
 
-  static bool Grow(Handle<WasmMemoryObject> memory, uint32_t count);
+  static bool Grow(Isolate* isolate, Handle<WasmMemoryObject> memory,
+                   uint32_t count);
 };
 
 // Representation of a WebAssembly.Instance JavaScript-level object.
@@ -105,6 +109,7 @@ class WasmInstanceObject : public JSObject {
     kMemoryArrayBuffer,
     kGlobalsArrayBuffer,
     kDebugInfo,
+    kWasmMemInstanceWrapper,
     kFieldCount
   };
 
@@ -115,10 +120,16 @@ class WasmInstanceObject : public JSObject {
   DECLARE_OPTIONAL_ACCESSORS(memory_buffer, JSArrayBuffer);
   DECLARE_OPTIONAL_ACCESSORS(memory_object, WasmMemoryObject);
   DECLARE_OPTIONAL_ACCESSORS(debug_info, WasmDebugInfo);
+  DECLARE_OPTIONAL_ACCESSORS(instance_wrapper, WasmInstanceWrapper);
 
   WasmModuleObject* module_object();
   wasm::WasmModule* module();
 
+  // Get the debug info associated with the given wasm object.
+  // If no debug info exists yet, it is created automatically.
+  static Handle<WasmDebugInfo> GetOrCreateDebugInfo(
+      Handle<WasmInstanceObject> instance);
+
   static Handle<WasmInstanceObject> New(
       Isolate* isolate, Handle<WasmCompiledModule> compiled_module);
 };
@@ -135,9 +146,39 @@ class WasmExportedFunction : public JSFunction {
 
   static Handle<WasmExportedFunction> New(Isolate* isolate,
                                           Handle<WasmInstanceObject> instance,
-                                          Handle<String> name,
-                                          Handle<Code> export_wrapper,
-                                          int arity, int func_index);
+                                          MaybeHandle<String> maybe_name,
+                                          int func_index, int arity,
+                                          Handle<Code> export_wrapper);
+};
+
+// Information shared by all WasmCompiledModule objects for the same module.
+class WasmSharedModuleData : public FixedArray {
+  enum Fields {
+    kModuleWrapper,
+    kModuleBytes,
+    kScript,
+    kAsmJsOffsetTable,
+    kFieldCount
+  };
+
+ public:
+  DECLARE_CASTS(WasmSharedModuleData);
+
+  DECLARE_GETTER(module, wasm::WasmModule);
+  DECLARE_OPTIONAL_ACCESSORS(module_bytes, SeqOneByteString);
+  DECLARE_GETTER(script, Script);
+  DECLARE_OPTIONAL_ACCESSORS(asm_js_offset_table, ByteArray);
+
+  static Handle<WasmSharedModuleData> New(
+      Isolate* isolate, Handle<Foreign> module_wrapper,
+      Handle<SeqOneByteString> module_bytes, Handle<Script> script,
+      Handle<ByteArray> asm_js_offset_table);
+
+  // Check whether this module was generated from asm.js source.
+  bool is_asm_js();
+
+  // Recreate the ModuleWrapper from the module bytes after deserialization.
+  static void RecreateModuleWrapper(Isolate*, Handle<WasmSharedModuleData>);
 };
 
 class WasmCompiledModule : public FixedArray {
@@ -149,7 +190,7 @@ class WasmCompiledModule : public FixedArray {
     return reinterpret_cast<WasmCompiledModule*>(fixed_array);
   }
 
-#define WCM_OBJECT_OR_WEAK(TYPE, NAME, ID)                           \
+#define WCM_OBJECT_OR_WEAK(TYPE, NAME, ID, TYPE_CHECK)               \
   Handle<TYPE> NAME() const { return handle(ptr_to_##NAME()); }      \
                                                                      \
   MaybeHandle<TYPE> maybe_##NAME() const {                           \
@@ -157,9 +198,15 @@ class WasmCompiledModule : public FixedArray {
     return MaybeHandle<TYPE>();                                      \
   }                                                                  \
                                                                      \
+  TYPE* maybe_ptr_to_##NAME() const {                                \
+    Object* obj = get(ID);                                           \
+    if (!(TYPE_CHECK)) return nullptr;                               \
+    return TYPE::cast(obj);                                          \
+  }                                                                  \
+                                                                     \
   TYPE* ptr_to_##NAME() const {                                      \
     Object* obj = get(ID);                                           \
-    if (!obj->Is##TYPE()) return nullptr;                            \
+    DCHECK(TYPE_CHECK);                                              \
     return TYPE::cast(obj);                                          \
   }                                                                  \
                                                                      \
@@ -167,11 +214,18 @@ class WasmCompiledModule : public FixedArray {
                                                                      \
   void set_ptr_to_##NAME(TYPE* value) { set(ID, value); }            \
                                                                      \
-  bool has_##NAME() const { return get(ID)->Is##TYPE(); }            \
+  bool has_##NAME() const {                                          \
+    Object* obj = get(ID);                                           \
+    return TYPE_CHECK;                                               \
+  }                                                                  \
                                                                      \
   void reset_##NAME() { set_undefined(ID); }
 
-#define WCM_OBJECT(TYPE, NAME) WCM_OBJECT_OR_WEAK(TYPE, NAME, kID_##NAME)
+#define WCM_OBJECT(TYPE, NAME) \
+  WCM_OBJECT_OR_WEAK(TYPE, NAME, kID_##NAME, obj->Is##TYPE())
+
+#define WCM_WASM_OBJECT(TYPE, NAME) \
+  WCM_OBJECT_OR_WEAK(TYPE, NAME, kID_##NAME, TYPE::Is##TYPE(obj))
 
 #define WCM_SMALL_NUMBER(TYPE, NAME)                               \
   TYPE NAME() const {                                              \
@@ -179,30 +233,29 @@ class WasmCompiledModule : public FixedArray {
   }                                                                \
   void set_##NAME(TYPE value) { set(kID_##NAME, Smi::FromInt(value)); }
 
-#define WCM_WEAK_LINK(TYPE, NAME)                        \
-  WCM_OBJECT_OR_WEAK(WeakCell, weak_##NAME, kID_##NAME); \
-                                                         \
-  Handle<TYPE> NAME() const {                            \
-    return handle(TYPE::cast(weak_##NAME()->value()));   \
+#define WCM_WEAK_LINK(TYPE, NAME)                                           \
+  WCM_OBJECT_OR_WEAK(WeakCell, weak_##NAME, kID_##NAME, obj->IsWeakCell()); \
+                                                                            \
+  Handle<TYPE> NAME() const {                                               \
+    return handle(TYPE::cast(weak_##NAME()->value()));                      \
   }
 
-#define CORE_WCM_PROPERTY_TABLE(MACRO)                \
-  MACRO(OBJECT, FixedArray, code_table)               \
-  MACRO(OBJECT, Foreign, module_wrapper)              \
-  /* For debugging: */                                \
-  MACRO(OBJECT, SeqOneByteString, module_bytes)       \
-  MACRO(OBJECT, Script, script)                       \
-  MACRO(OBJECT, ByteArray, asm_js_offset_tables)      \
-  /* End of debugging stuff */                        \
-  MACRO(OBJECT, FixedArray, function_tables)          \
-  MACRO(OBJECT, FixedArray, empty_function_tables)    \
-  MACRO(OBJECT, JSArrayBuffer, memory)                \
-  MACRO(SMALL_NUMBER, uint32_t, min_mem_pages)        \
-  MACRO(SMALL_NUMBER, uint32_t, max_mem_pages)        \
-  MACRO(WEAK_LINK, WasmCompiledModule, next_instance) \
-  MACRO(WEAK_LINK, WasmCompiledModule, prev_instance) \
-  MACRO(WEAK_LINK, JSObject, owning_instance)         \
-  MACRO(WEAK_LINK, JSObject, wasm_module)
+#define CORE_WCM_PROPERTY_TABLE(MACRO)                  \
+  MACRO(WASM_OBJECT, WasmSharedModuleData, shared)      \
+  MACRO(OBJECT, Context, native_context)                \
+  MACRO(SMALL_NUMBER, uint32_t, num_imported_functions) \
+  MACRO(OBJECT, FixedArray, code_table)                 \
+  MACRO(OBJECT, FixedArray, weak_exported_functions)    \
+  MACRO(OBJECT, FixedArray, function_tables)            \
+  MACRO(OBJECT, FixedArray, signature_tables)           \
+  MACRO(OBJECT, FixedArray, empty_function_tables)      \
+  MACRO(OBJECT, JSArrayBuffer, memory)                  \
+  MACRO(SMALL_NUMBER, uint32_t, min_mem_pages)          \
+  MACRO(SMALL_NUMBER, uint32_t, max_mem_pages)          \
+  MACRO(WEAK_LINK, WasmCompiledModule, next_instance)   \
+  MACRO(WEAK_LINK, WasmCompiledModule, prev_instance)   \
+  MACRO(WEAK_LINK, JSObject, owning_instance)           \
+  MACRO(WEAK_LINK, WasmModuleObject, wasm_module)
 
 #if DEBUG
 #define DEBUG_ONLY_TABLE(MACRO) MACRO(SMALL_NUMBER, uint32_t, instance_id)
@@ -223,8 +276,8 @@ class WasmCompiledModule : public FixedArray {
   };
 
  public:
-  static Handle<WasmCompiledModule> New(
-      Isolate* isolate, Handle<Managed<wasm::WasmModule>> module_wrapper);
+  static Handle<WasmCompiledModule> New(Isolate* isolate,
+                                        Handle<WasmSharedModuleData> shared);
 
   static Handle<WasmCompiledModule> Clone(Isolate* isolate,
                                           Handle<WasmCompiledModule> module) {
@@ -234,30 +287,93 @@ class WasmCompiledModule : public FixedArray {
     ret->reset_weak_owning_instance();
     ret->reset_weak_next_instance();
     ret->reset_weak_prev_instance();
+    ret->reset_weak_exported_functions();
     return ret;
   }
 
   uint32_t mem_size() const;
   uint32_t default_mem_size() const;
 
-  wasm::WasmModule* module() const;
-
 #define DECLARATION(KIND, TYPE, NAME) WCM_##KIND(TYPE, NAME)
   WCM_PROPERTY_TABLE(DECLARATION)
 #undef DECLARATION
 
+// Allow to call method on WasmSharedModuleData also on this object.
+#define FORWARD_SHARED(type, name) \
+  type name() { return shared()->name(); }
+  FORWARD_SHARED(SeqOneByteString*, module_bytes)
+  FORWARD_SHARED(wasm::WasmModule*, module)
+  FORWARD_SHARED(Script*, script)
+  FORWARD_SHARED(bool, is_asm_js)
+#undef FORWARD_SHARED
+
   static bool IsWasmCompiledModule(Object* obj);
 
   void PrintInstancesChain();
 
+  // Recreate the ModuleWrapper from the module bytes after deserialization.
   static void RecreateModuleWrapper(Isolate* isolate,
-                                    Handle<FixedArray> compiled_module);
+                                    Handle<WasmCompiledModule> compiled_module);
 
-  // Extract a function name from the given wasm instance.
+  // Get the function name of the function identified by the given index.
   // Returns a null handle if the function is unnamed or the name is not a valid
   // UTF-8 string.
-  static MaybeHandle<String> GetFunctionName(
-      Handle<WasmCompiledModule> compiled_module, uint32_t func_index);
+  static MaybeHandle<String> GetFunctionNameOrNull(
+      Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+      uint32_t func_index);
+
+  // Get the function name of the function identified by the given index.
+  // Returns "<WASM UNNAMED>" if the function is unnamed or the name is not a
+  // valid UTF-8 string.
+  static Handle<String> GetFunctionName(
+      Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+      uint32_t func_index);
+
+  // Get the raw bytes of the function name of the function identified by the
+  // given index.
+  // Meant to be used for debugging or frame printing.
+  // Does not allocate, hence gc-safe.
+  Vector<const uint8_t> GetRawFunctionName(uint32_t func_index);
+
+  // Return the byte offset of the function identified by the given index.
+  // The offset will be relative to the start of the module bytes.
+  // Returns -1 if the function index is invalid.
+  int GetFunctionOffset(uint32_t func_index);
+
+  // Returns the function containing the given byte offset.
+  // Returns -1 if the byte offset is not contained in any function of this
+  // module.
+  int GetContainingFunction(uint32_t byte_offset);
+
+  // Translate from byte offset in the module to function number and byte offset
+  // within that function, encoded as line and column in the position info.
+  // Returns true if the position is valid inside this module, false otherwise.
+  bool GetPositionInfo(uint32_t position, Script::PositionInfo* info);
+
+  // Get the asm.js source position from a byte offset.
+  // Must only be called if the associated wasm object was created from asm.js.
+  static int GetAsmJsSourcePosition(Handle<WasmCompiledModule> compiled_module,
+                                    uint32_t func_index, uint32_t byte_offset,
+                                    bool is_at_number_conversion);
+
+  // Compute the disassembly of a wasm function.
+  // Returns the disassembly string and a list of <byte_offset, line, column>
+  // entries, mapping wasm byte offsets to line and column in the disassembly.
+  // The list is guaranteed to be ordered by the byte_offset.
+  // Returns an empty string and empty vector if the function index is invalid.
+  debug::WasmDisassembly DisassembleFunction(int func_index);
+
+  // Extract a portion of the wire bytes as UTF-8 string.
+  // Returns a null handle if the respective bytes do not form a valid UTF-8
+  // string.
+  static MaybeHandle<String> ExtractUtf8StringFromModuleBytes(
+      Isolate* isolate, Handle<WasmCompiledModule> compiled_module,
+      uint32_t offset, uint32_t size);
+
+  // Get a list of all possible breakpoints within a given range of this module.
+  bool GetPossibleBreakpoints(const debug::Location& start,
+                              const debug::Location& end,
+                              std::vector<debug::Location>* locations);
 
  private:
   void InitId();
@@ -267,36 +383,79 @@ class WasmCompiledModule : public FixedArray {
 
 class WasmDebugInfo : public FixedArray {
  public:
-  enum class Fields { kFieldCount };
-
-  static Handle<WasmDebugInfo> New(Handle<JSObject> wasm);
+  enum Fields {
+    kInstance,
+    kInterpreterHandle,
+    kInterpretedFunctions,
+    kFieldCount
+  };
 
-  static bool IsDebugInfo(Object* object);
-  static WasmDebugInfo* cast(Object* object);
+  static Handle<WasmDebugInfo> New(Handle<WasmInstanceObject>);
 
-  JSObject* wasm_instance();
+  static bool IsDebugInfo(Object*);
+  static WasmDebugInfo* cast(Object*);
 
-  bool SetBreakPoint(int byte_offset);
+  static void SetBreakpoint(Handle<WasmDebugInfo>, int func_index, int offset);
 
-  // Get the Script for the specified function.
-  static Script* GetFunctionScript(Handle<WasmDebugInfo> debug_info,
-                                   int func_index);
+  static void RunInterpreter(Handle<WasmDebugInfo>, int func_index,
+                             uint8_t* arg_buffer);
 
-  // Disassemble the specified function from this module.
-  static Handle<String> DisassembleFunction(Handle<WasmDebugInfo> debug_info,
-                                            int func_index);
+  DECLARE_GETTER(wasm_instance, WasmInstanceObject);
+};
 
-  // Get the offset table for the specified function, mapping from byte offsets
-  // to position in the disassembly.
-  // Returns an array with three entries per instruction: byte offset, line and
-  // column.
-  static Handle<FixedArray> GetFunctionOffsetTable(
-      Handle<WasmDebugInfo> debug_info, int func_index);
+class WasmInstanceWrapper : public FixedArray {
+ public:
+  static Handle<WasmInstanceWrapper> New(Isolate* isolate,
+                                         Handle<WasmInstanceObject> instance);
+  static WasmInstanceWrapper* cast(Object* fixed_array) {
+    SLOW_DCHECK(IsWasmInstanceWrapper(fixed_array));
+    return reinterpret_cast<WasmInstanceWrapper*>(fixed_array);
+  }
+  static bool IsWasmInstanceWrapper(Object* obj);
+  bool has_instance() { return get(kWrapperInstanceObject)->IsWeakCell(); }
+  Handle<WasmInstanceObject> instance_object() {
+    Object* obj = get(kWrapperInstanceObject);
+    DCHECK(obj->IsWeakCell());
+    WeakCell* cell = WeakCell::cast(obj);
+    DCHECK(cell->value()->IsJSObject());
+    return handle(WasmInstanceObject::cast(cell->value()));
+  }
+  bool has_next() { return IsWasmInstanceWrapper(get(kNextInstanceWrapper)); }
+  bool has_previous() {
+    return IsWasmInstanceWrapper(get(kPreviousInstanceWrapper));
+  }
+  void set_instance_object(Handle<JSObject> instance, Isolate* isolate);
+  void set_next_wrapper(Object* obj) {
+    DCHECK(IsWasmInstanceWrapper(obj));
+    set(kNextInstanceWrapper, obj);
+  }
+  void set_previous_wrapper(Object* obj) {
+    DCHECK(IsWasmInstanceWrapper(obj));
+    set(kPreviousInstanceWrapper, obj);
+  }
+  Handle<WasmInstanceWrapper> next_wrapper() {
+    Object* obj = get(kNextInstanceWrapper);
+    DCHECK(IsWasmInstanceWrapper(obj));
+    return handle(WasmInstanceWrapper::cast(obj));
+  }
+  Handle<WasmInstanceWrapper> previous_wrapper() {
+    Object* obj = get(kPreviousInstanceWrapper);
+    DCHECK(IsWasmInstanceWrapper(obj));
+    return handle(WasmInstanceWrapper::cast(obj));
+  }
+  void reset_next_wrapper() { set_undefined(kNextInstanceWrapper); }
+  void reset_previous_wrapper() { set_undefined(kPreviousInstanceWrapper); }
+  void reset() {
+    for (int kID = 0; kID < kWrapperPropertyCount; kID++) set_undefined(kID);
+  }
 
-  // Get the asm.js source position from a byte offset.
-  // Must only be called if the associated wasm object was created from asm.js.
-  static int GetAsmJsSourcePosition(Handle<WasmDebugInfo> debug_info,
-                                    int func_index, int byte_offset);
+ private:
+  enum {
+    kWrapperInstanceObject,
+    kNextInstanceWrapper,
+    kPreviousInstanceWrapper,
+    kWrapperPropertyCount
+  };
 };
 
 #undef DECLARE_ACCESSORS
diff --git a/deps/v8/src/wasm/wasm-opcodes.cc b/deps/v8/src/wasm/wasm-opcodes.cc
index 8f81b81a50..2a00a73cbd 100644
--- a/deps/v8/src/wasm/wasm-opcodes.cc
+++ b/deps/v8/src/wasm/wasm-opcodes.cc
@@ -4,13 +4,14 @@
 
 #include "src/wasm/wasm-opcodes.h"
 #include "src/messages.h"
+#include "src/runtime/runtime.h"
 #include "src/signature.h"
 
 namespace v8 {
 namespace internal {
 namespace wasm {
 
-typedef Signature<LocalType> FunctionSig;
+typedef Signature<ValueType> FunctionSig;
 
 const char* WasmOpcodes::OpcodeName(WasmOpcode opcode) {
   switch (opcode) {
@@ -69,7 +70,7 @@ enum WasmOpcodeSig { FOREACH_SIGNATURE(DECLARE_SIG_ENUM) };
 
 // TODO(titzer): not static-initializer safe. Wrap in LazyInstance.
 #define DECLARE_SIG(name, ...)                      \
-  static LocalType kTypes_##name[] = {__VA_ARGS__}; \
+  static ValueType kTypes_##name[] = {__VA_ARGS__}; \
   static const FunctionSig kSig_##name(             \
       1, static_cast<int>(arraysize(kTypes_##name)) - 1, kTypes_##name);
 
diff --git a/deps/v8/src/wasm/wasm-opcodes.h b/deps/v8/src/wasm/wasm-opcodes.h
index ec22579bd7..6c231ac69b 100644
--- a/deps/v8/src/wasm/wasm-opcodes.h
+++ b/deps/v8/src/wasm/wasm-opcodes.h
@@ -7,6 +7,7 @@
 
 #include "src/globals.h"
 #include "src/machine-type.h"
+#include "src/runtime/runtime.h"
 #include "src/signature.h"
 
 namespace v8 {
@@ -14,7 +15,7 @@ namespace internal {
 namespace wasm {
 
 // Binary encoding of local types.
-enum LocalTypeCode {
+enum ValueTypeCode {
   kLocalVoid = 0x40,
   kLocalI32 = 0x7f,
   kLocalI64 = 0x7e,
@@ -26,19 +27,18 @@ enum LocalTypeCode {
 // Type code for multi-value block types.
 static const uint8_t kMultivalBlock = 0x41;
 
-// We reuse the internal machine type to represent WebAssembly AST types.
+// We reuse the internal machine type to represent WebAssembly types.
 // A typedef improves readability without adding a whole new type system.
-typedef MachineRepresentation LocalType;
-const LocalType kAstStmt = MachineRepresentation::kNone;
-const LocalType kAstI32 = MachineRepresentation::kWord32;
-const LocalType kAstI64 = MachineRepresentation::kWord64;
-const LocalType kAstF32 = MachineRepresentation::kFloat32;
-const LocalType kAstF64 = MachineRepresentation::kFloat64;
-const LocalType kAstS128 = MachineRepresentation::kSimd128;
-// We use kTagged here because kNone is already used by kAstStmt.
-const LocalType kAstEnd = MachineRepresentation::kTagged;
-
-typedef Signature<LocalType> FunctionSig;
+typedef MachineRepresentation ValueType;
+const ValueType kWasmStmt = MachineRepresentation::kNone;
+const ValueType kWasmI32 = MachineRepresentation::kWord32;
+const ValueType kWasmI64 = MachineRepresentation::kWord64;
+const ValueType kWasmF32 = MachineRepresentation::kFloat32;
+const ValueType kWasmF64 = MachineRepresentation::kFloat64;
+const ValueType kWasmS128 = MachineRepresentation::kSimd128;
+const ValueType kWasmVar = MachineRepresentation::kTagged;
+
+typedef Signature<ValueType> FunctionSig;
 std::ostream& operator<<(std::ostream& os, const FunctionSig& function);
 
 typedef Vector<const char> WasmName;
@@ -77,8 +77,7 @@ const WasmCodePosition kNoCodePosition = -1;
   V(I32Const, 0x41, _)         \
   V(I64Const, 0x42, _)         \
   V(F32Const, 0x43, _)         \
-  V(F64Const, 0x44, _)         \
-  V(I8Const, 0xcb, _ /* TODO(titzer): V8 specific, remove */)
+  V(F64Const, 0x44, _)
 
 // Load memory expressions.
 #define FOREACH_LOAD_MEM_OPCODE(V) \
@@ -276,7 +275,6 @@ const WasmCodePosition kNoCodePosition = -1;
 
 #define FOREACH_SIMD_0_OPERAND_OPCODE(V) \
   V(F32x4Splat, 0xe500, s_f)             \
-  V(F32x4ReplaceLane, 0xe502, s_sif)     \
   V(F32x4Abs, 0xe503, s_s)               \
   V(F32x4Neg, 0xe504, s_s)               \
   V(F32x4Sqrt, 0xe505, s_s)              \
@@ -296,13 +294,9 @@ const WasmCodePosition kNoCodePosition = -1;
   V(F32x4Le, 0xe513, s_ss)               \
   V(F32x4Gt, 0xe514, s_ss)               \
   V(F32x4Ge, 0xe515, s_ss)               \
-  V(F32x4Select, 0xe516, s_sss)          \
-  V(F32x4Swizzle, 0xe517, s_s)           \
-  V(F32x4Shuffle, 0xe518, s_ss)          \
   V(F32x4FromInt32x4, 0xe519, s_s)       \
   V(F32x4FromUint32x4, 0xe51a, s_s)      \
   V(I32x4Splat, 0xe51b, s_i)             \
-  V(I32x4ReplaceLane, 0xe51d, s_sii)     \
   V(I32x4Neg, 0xe51e, s_s)               \
   V(I32x4Add, 0xe51f, s_ss)              \
   V(I32x4Sub, 0xe520, s_ss)              \
@@ -330,7 +324,6 @@ const WasmCodePosition kNoCodePosition = -1;
   V(I32x4Ge_u, 0xe536, s_ss)             \
   V(Ui32x4FromFloat32x4, 0xe537, s_s)    \
   V(I16x8Splat, 0xe538, s_i)             \
-  V(I16x8ReplaceLane, 0xe53a, s_sii)     \
   V(I16x8Neg, 0xe53b, s_s)               \
   V(I16x8Add, 0xe53c, s_ss)              \
   V(I16x8AddSaturate_s, 0xe53d, s_ss)    \
@@ -360,7 +353,6 @@ const WasmCodePosition kNoCodePosition = -1;
   V(I16x8Gt_u, 0xe555, s_ss)             \
   V(I16x8Ge_u, 0xe556, s_ss)             \
   V(I8x16Splat, 0xe557, s_i)             \
-  V(I8x16ReplaceLane, 0xe559, s_sii)     \
   V(I8x16Neg, 0xe55a, s_s)               \
   V(I8x16Add, 0xe55b, s_ss)              \
   V(I8x16AddSaturate_s, 0xe55c, s_ss)    \
@@ -392,13 +384,20 @@ const WasmCodePosition kNoCodePosition = -1;
   V(S128And, 0xe576, s_ss)               \
   V(S128Ior, 0xe577, s_ss)               \
   V(S128Xor, 0xe578, s_ss)               \
-  V(S128Not, 0xe579, s_s)
+  V(S128Not, 0xe579, s_s)                \
+  V(S32x4Select, 0xe580, s_sss)          \
+  V(S32x4Swizzle, 0xe581, s_s)           \
+  V(S32x4Shuffle, 0xe582, s_ss)
 
 #define FOREACH_SIMD_1_OPERAND_OPCODE(V) \
   V(F32x4ExtractLane, 0xe501, _)         \
+  V(F32x4ReplaceLane, 0xe502, _)         \
   V(I32x4ExtractLane, 0xe51c, _)         \
+  V(I32x4ReplaceLane, 0xe51d, _)         \
   V(I16x8ExtractLane, 0xe539, _)         \
-  V(I8x16ExtractLane, 0xe558, _)
+  V(I16x8ReplaceLane, 0xe53a, _)         \
+  V(I8x16ExtractLane, 0xe558, _)         \
+  V(I8x16ReplaceLane, 0xe559, _)
 
 #define FOREACH_ATOMIC_OPCODE(V)               \
   V(I32AtomicAdd8S, 0xe601, i_ii)              \
@@ -451,45 +450,43 @@ const WasmCodePosition kNoCodePosition = -1;
   FOREACH_ATOMIC_OPCODE(V)
 
 // All signatures.
-#define FOREACH_SIGNATURE(V)         \
-  FOREACH_SIMD_SIGNATURE(V)          \
-  V(i_ii, kAstI32, kAstI32, kAstI32) \
-  V(i_i, kAstI32, kAstI32)           \
-  V(i_v, kAstI32)                    \
-  V(i_ff, kAstI32, kAstF32, kAstF32) \
-  V(i_f, kAstI32, kAstF32)           \
-  V(i_dd, kAstI32, kAstF64, kAstF64) \
-  V(i_d, kAstI32, kAstF64)           \
-  V(i_l, kAstI32, kAstI64)           \
-  V(l_ll, kAstI64, kAstI64, kAstI64) \
-  V(i_ll, kAstI32, kAstI64, kAstI64) \
-  V(l_l, kAstI64, kAstI64)           \
-  V(l_i, kAstI64, kAstI32)           \
-  V(l_f, kAstI64, kAstF32)           \
-  V(l_d, kAstI64, kAstF64)           \
-  V(f_ff, kAstF32, kAstF32, kAstF32) \
-  V(f_f, kAstF32, kAstF32)           \
-  V(f_d, kAstF32, kAstF64)           \
-  V(f_i, kAstF32, kAstI32)           \
-  V(f_l, kAstF32, kAstI64)           \
-  V(d_dd, kAstF64, kAstF64, kAstF64) \
-  V(d_d, kAstF64, kAstF64)           \
-  V(d_f, kAstF64, kAstF32)           \
-  V(d_i, kAstF64, kAstI32)           \
-  V(d_l, kAstF64, kAstI64)           \
-  V(d_id, kAstF64, kAstI32, kAstF64) \
-  V(f_if, kAstF32, kAstI32, kAstF32) \
-  V(l_il, kAstI64, kAstI32, kAstI64)
-
-#define FOREACH_SIMD_SIGNATURE(V)                  \
-  V(s_s, kAstS128, kAstS128)                       \
-  V(s_f, kAstS128, kAstF32)                        \
-  V(s_sif, kAstS128, kAstS128, kAstI32, kAstF32)   \
-  V(s_ss, kAstS128, kAstS128, kAstS128)            \
-  V(s_sss, kAstS128, kAstS128, kAstS128, kAstS128) \
-  V(s_i, kAstS128, kAstI32)                        \
-  V(s_sii, kAstS128, kAstS128, kAstI32, kAstI32)   \
-  V(s_si, kAstS128, kAstS128, kAstI32)
+#define FOREACH_SIGNATURE(V)            \
+  FOREACH_SIMD_SIGNATURE(V)             \
+  V(i_ii, kWasmI32, kWasmI32, kWasmI32) \
+  V(i_i, kWasmI32, kWasmI32)            \
+  V(i_v, kWasmI32)                      \
+  V(i_ff, kWasmI32, kWasmF32, kWasmF32) \
+  V(i_f, kWasmI32, kWasmF32)            \
+  V(i_dd, kWasmI32, kWasmF64, kWasmF64) \
+  V(i_d, kWasmI32, kWasmF64)            \
+  V(i_l, kWasmI32, kWasmI64)            \
+  V(l_ll, kWasmI64, kWasmI64, kWasmI64) \
+  V(i_ll, kWasmI32, kWasmI64, kWasmI64) \
+  V(l_l, kWasmI64, kWasmI64)            \
+  V(l_i, kWasmI64, kWasmI32)            \
+  V(l_f, kWasmI64, kWasmF32)            \
+  V(l_d, kWasmI64, kWasmF64)            \
+  V(f_ff, kWasmF32, kWasmF32, kWasmF32) \
+  V(f_f, kWasmF32, kWasmF32)            \
+  V(f_d, kWasmF32, kWasmF64)            \
+  V(f_i, kWasmF32, kWasmI32)            \
+  V(f_l, kWasmF32, kWasmI64)            \
+  V(d_dd, kWasmF64, kWasmF64, kWasmF64) \
+  V(d_d, kWasmF64, kWasmF64)            \
+  V(d_f, kWasmF64, kWasmF32)            \
+  V(d_i, kWasmF64, kWasmI32)            \
+  V(d_l, kWasmF64, kWasmI64)            \
+  V(d_id, kWasmF64, kWasmI32, kWasmF64) \
+  V(f_if, kWasmF32, kWasmI32, kWasmF32) \
+  V(l_il, kWasmI64, kWasmI32, kWasmI64)
+
+#define FOREACH_SIMD_SIGNATURE(V)                      \
+  V(s_s, kWasmS128, kWasmS128)                         \
+  V(s_f, kWasmS128, kWasmF32)                          \
+  V(s_ss, kWasmS128, kWasmS128, kWasmS128)             \
+  V(s_sss, kWasmS128, kWasmS128, kWasmS128, kWasmS128) \
+  V(s_i, kWasmS128, kWasmI32)                          \
+  V(s_si, kWasmS128, kWasmS128, kWasmI32)
 
 #define FOREACH_PREFIX(V) \
   V(Simd, 0xe5)           \
@@ -514,8 +511,7 @@ enum WasmOpcode {
   V(TrapRemByZero)                 \
   V(TrapFloatUnrepresentable)      \
   V(TrapFuncInvalid)               \
-  V(TrapFuncSigMismatch)           \
-  V(TrapInvalidIndex)
+  V(TrapFuncSigMismatch)
 
 enum TrapReason {
 #define DECLARE_ENUM(name) k##name,
@@ -541,21 +537,21 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
     return 1 << ElementSizeLog2Of(type.representation());
   }
 
-  static byte MemSize(LocalType type) { return 1 << ElementSizeLog2Of(type); }
+  static byte MemSize(ValueType type) { return 1 << ElementSizeLog2Of(type); }
 
-  static LocalTypeCode LocalTypeCodeFor(LocalType type) {
+  static ValueTypeCode ValueTypeCodeFor(ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         return kLocalI32;
-      case kAstI64:
+      case kWasmI64:
         return kLocalI64;
-      case kAstF32:
+      case kWasmF32:
         return kLocalF32;
-      case kAstF64:
+      case kWasmF64:
         return kLocalF64;
-      case kAstS128:
+      case kWasmS128:
         return kLocalS128;
-      case kAstStmt:
+      case kWasmStmt:
         return kLocalVoid;
       default:
         UNREACHABLE();
@@ -563,19 +559,19 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
     }
   }
 
-  static MachineType MachineTypeFor(LocalType type) {
+  static MachineType MachineTypeFor(ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         return MachineType::Int32();
-      case kAstI64:
+      case kWasmI64:
         return MachineType::Int64();
-      case kAstF32:
+      case kWasmF32:
         return MachineType::Float32();
-      case kAstF64:
+      case kWasmF64:
         return MachineType::Float64();
-      case kAstS128:
+      case kWasmS128:
         return MachineType::Simd128();
-      case kAstStmt:
+      case kWasmStmt:
         return MachineType::None();
       default:
         UNREACHABLE();
@@ -583,32 +579,32 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
     }
   }
 
-  static LocalType LocalTypeFor(MachineType type) {
+  static ValueType ValueTypeFor(MachineType type) {
     if (type == MachineType::Int8()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Uint8()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Int16()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Uint16()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Int32()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Uint32()) {
-      return kAstI32;
+      return kWasmI32;
     } else if (type == MachineType::Int64()) {
-      return kAstI64;
+      return kWasmI64;
     } else if (type == MachineType::Uint64()) {
-      return kAstI64;
+      return kWasmI64;
     } else if (type == MachineType::Float32()) {
-      return kAstF32;
+      return kWasmF32;
     } else if (type == MachineType::Float64()) {
-      return kAstF64;
+      return kWasmF64;
     } else if (type == MachineType::Simd128()) {
-      return kAstS128;
+      return kWasmS128;
     } else {
       UNREACHABLE();
-      return kAstI32;
+      return kWasmI32;
     }
   }
 
@@ -639,44 +635,43 @@ class V8_EXPORT_PRIVATE WasmOpcodes {
     }
   }
 
-  static char ShortNameOf(LocalType type) {
+  static char ShortNameOf(ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         return 'i';
-      case kAstI64:
+      case kWasmI64:
         return 'l';
-      case kAstF32:
+      case kWasmF32:
         return 'f';
-      case kAstF64:
+      case kWasmF64:
         return 'd';
-      case kAstS128:
+      case kWasmS128:
         return 's';
-      case kAstStmt:
+      case kWasmStmt:
         return 'v';
-      case kAstEnd:
-        return 'x';
+      case kWasmVar:
+        return '*';
       default:
-        UNREACHABLE();
         return '?';
     }
   }
 
-  static const char* TypeName(LocalType type) {
+  static const char* TypeName(ValueType type) {
     switch (type) {
-      case kAstI32:
+      case kWasmI32:
         return "i32";
-      case kAstI64:
+      case kWasmI64:
         return "i64";
-      case kAstF32:
+      case kWasmF32:
         return "f32";
-      case kAstF64:
+      case kWasmF64:
         return "f64";
-      case kAstS128:
+      case kWasmS128:
         return "s128";
-      case kAstStmt:
+      case kWasmStmt:
         return "<stmt>";
-      case kAstEnd:
-        return "<end>";
+      case kWasmVar:
+        return "<var>";
       default:
         return "<unknown>";
     }
diff --git a/deps/v8/src/wasm/wasm-result.cc b/deps/v8/src/wasm/wasm-result.cc
index 6d535e3f57..e22f9ad442 100644
--- a/deps/v8/src/wasm/wasm-result.cc
+++ b/deps/v8/src/wasm/wasm-result.cc
@@ -64,14 +64,25 @@ void ErrorThrower::RangeError(const char* format, ...) {
 
 void ErrorThrower::CompileError(const char* format, ...) {
   if (error()) return;
+  wasm_error_ = true;
   va_list arguments;
   va_start(arguments, format);
   Format(isolate_->wasm_compile_error_function(), format, arguments);
   va_end(arguments);
 }
 
+void ErrorThrower::LinkError(const char* format, ...) {
+  if (error()) return;
+  wasm_error_ = true;
+  va_list arguments;
+  va_start(arguments, format);
+  Format(isolate_->wasm_link_error_function(), format, arguments);
+  va_end(arguments);
+}
+
 void ErrorThrower::RuntimeError(const char* format, ...) {
   if (error()) return;
+  wasm_error_ = true;
   va_list arguments;
   va_start(arguments, format);
   Format(isolate_->wasm_runtime_error_function(), format, arguments);
diff --git a/deps/v8/src/wasm/wasm-result.h b/deps/v8/src/wasm/wasm-result.h
index 53c6b8dcf9..004ac22d33 100644
--- a/deps/v8/src/wasm/wasm-result.h
+++ b/deps/v8/src/wasm/wasm-result.h
@@ -95,6 +95,7 @@ class V8_EXPORT_PRIVATE ErrorThrower {
   PRINTF_FORMAT(2, 3) void TypeError(const char* fmt, ...);
   PRINTF_FORMAT(2, 3) void RangeError(const char* fmt, ...);
   PRINTF_FORMAT(2, 3) void CompileError(const char* fmt, ...);
+  PRINTF_FORMAT(2, 3) void LinkError(const char* fmt, ...);
   PRINTF_FORMAT(2, 3) void RuntimeError(const char* fmt, ...);
 
   template <typename T>
@@ -111,6 +112,7 @@ class V8_EXPORT_PRIVATE ErrorThrower {
   }
 
   bool error() const { return !exception_.is_null(); }
+  bool wasm_error() { return wasm_error_; }
 
  private:
   void Format(i::Handle<i::JSFunction> constructor, const char* fmt, va_list);
@@ -118,6 +120,7 @@ class V8_EXPORT_PRIVATE ErrorThrower {
   i::Isolate* isolate_;
   const char* context_;
   i::Handle<i::Object> exception_;
+  bool wasm_error_ = false;
 };
 }  // namespace wasm
 }  // namespace internal
diff --git a/deps/v8/src/wasm/wasm-text.cc b/deps/v8/src/wasm/wasm-text.cc
new file mode 100644
index 0000000000..1878095b09
--- /dev/null
+++ b/deps/v8/src/wasm/wasm-text.cc
@@ -0,0 +1,312 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/wasm/wasm-text.h"
+
+#include "src/debug/interface-types.h"
+#include "src/ostreams.h"
+#include "src/vector.h"
+#include "src/wasm/function-body-decoder.h"
+#include "src/wasm/wasm-module.h"
+#include "src/wasm/wasm-opcodes.h"
+#include "src/zone/zone.h"
+
+using namespace v8;
+using namespace v8::internal;
+using namespace v8::internal::wasm;
+
+namespace {
+const char *GetOpName(WasmOpcode opcode) {
+#define CASE_OP(name, str) \
+  case kExpr##name:        \
+    return str;
+#define CASE_I32_OP(name, str) CASE_OP(I32##name, "i32." str)
+#define CASE_I64_OP(name, str) CASE_OP(I64##name, "i64." str)
+#define CASE_F32_OP(name, str) CASE_OP(F32##name, "f32." str)
+#define CASE_F64_OP(name, str) CASE_OP(F64##name, "f64." str)
+#define CASE_INT_OP(name, str) CASE_I32_OP(name, str) CASE_I64_OP(name, str)
+#define CASE_FLOAT_OP(name, str) CASE_F32_OP(name, str) CASE_F64_OP(name, str)
+#define CASE_ALL_OP(name, str) CASE_FLOAT_OP(name, str) CASE_INT_OP(name, str)
+#define CASE_SIGN_OP(TYPE, name, str) \
+  CASE_##TYPE##_OP(name##S, str "_s") CASE_##TYPE##_OP(name##U, str "_u")
+#define CASE_ALL_SIGN_OP(name, str) \
+  CASE_FLOAT_OP(name, str) CASE_SIGN_OP(INT, name, str)
+#define CASE_CONVERT_OP(name, RES, SRC, src_suffix, str) \
+  CASE_##RES##_OP(U##name##SRC, str "_u/" src_suffix)    \
+      CASE_##RES##_OP(S##name##SRC, str "_s/" src_suffix)
+
+  switch (opcode) {
+    CASE_INT_OP(Eqz, "eqz")
+    CASE_ALL_OP(Eq, "eq")
+    CASE_ALL_OP(Ne, "ne")
+    CASE_ALL_OP(Add, "add")
+    CASE_ALL_OP(Sub, "sub")
+    CASE_ALL_OP(Mul, "mul")
+    CASE_ALL_SIGN_OP(Lt, "lt")
+    CASE_ALL_SIGN_OP(Gt, "gt")
+    CASE_ALL_SIGN_OP(Le, "le")
+    CASE_ALL_SIGN_OP(Ge, "ge")
+    CASE_INT_OP(Clz, "clz")
+    CASE_INT_OP(Ctz, "ctz")
+    CASE_INT_OP(Popcnt, "popcnt")
+    CASE_ALL_SIGN_OP(Div, "div")
+    CASE_SIGN_OP(INT, Rem, "rem")
+    CASE_INT_OP(And, "and")
+    CASE_INT_OP(Ior, "or")
+    CASE_INT_OP(Xor, "xor")
+    CASE_INT_OP(Shl, "shl")
+    CASE_SIGN_OP(INT, Shr, "shr")
+    CASE_INT_OP(Rol, "rol")
+    CASE_INT_OP(Ror, "ror")
+    CASE_FLOAT_OP(Abs, "abs")
+    CASE_FLOAT_OP(Neg, "neg")
+    CASE_FLOAT_OP(Ceil, "ceil")
+    CASE_FLOAT_OP(Floor, "floor")
+    CASE_FLOAT_OP(Trunc, "trunc")
+    CASE_FLOAT_OP(NearestInt, "nearest")
+    CASE_FLOAT_OP(Sqrt, "sqrt")
+    CASE_FLOAT_OP(Min, "min")
+    CASE_FLOAT_OP(Max, "max")
+    CASE_FLOAT_OP(CopySign, "copysign")
+    CASE_I32_OP(ConvertI64, "wrap/i64")
+    CASE_CONVERT_OP(Convert, INT, F32, "f32", "trunc")
+    CASE_CONVERT_OP(Convert, INT, F64, "f64", "trunc")
+    CASE_CONVERT_OP(Convert, I64, I32, "i32", "extend")
+    CASE_CONVERT_OP(Convert, F32, I32, "i32", "convert")
+    CASE_CONVERT_OP(Convert, F32, I64, "i64", "convert")
+    CASE_F32_OP(ConvertF64, "demote/f64")
+    CASE_CONVERT_OP(Convert, F64, I32, "i32", "convert")
+    CASE_CONVERT_OP(Convert, F64, I64, "i64", "convert")
+    CASE_F64_OP(ConvertF32, "promote/f32")
+    CASE_I32_OP(ReinterpretF32, "reinterpret/f32")
+    CASE_I64_OP(ReinterpretF64, "reinterpret/f64")
+    CASE_F32_OP(ReinterpretI32, "reinterpret/i32")
+    CASE_F64_OP(ReinterpretI64, "reinterpret/i64")
+    CASE_OP(Unreachable, "unreachable")
+    CASE_OP(Nop, "nop")
+    CASE_OP(Return, "return")
+    CASE_OP(MemorySize, "current_memory")
+    CASE_OP(GrowMemory, "grow_memory")
+    CASE_OP(Loop, "loop")
+    CASE_OP(If, "if")
+    CASE_OP(Block, "block")
+    CASE_OP(Try, "try")
+    CASE_OP(Throw, "throw")
+    CASE_OP(Catch, "catch")
+    CASE_OP(Drop, "drop")
+    CASE_OP(Select, "select")
+    CASE_ALL_OP(LoadMem, "load")
+    CASE_SIGN_OP(INT, LoadMem8, "load8")
+    CASE_SIGN_OP(INT, LoadMem16, "load16")
+    CASE_SIGN_OP(I64, LoadMem32, "load32")
+    CASE_ALL_OP(StoreMem, "store")
+    CASE_INT_OP(StoreMem8, "store8")
+    CASE_INT_OP(StoreMem16, "store16")
+    CASE_I64_OP(StoreMem32, "store32")
+    CASE_OP(SetLocal, "set_local")
+    CASE_OP(GetLocal, "get_local")
+    CASE_OP(TeeLocal, "tee_local")
+    CASE_OP(GetGlobal, "get_global")
+    CASE_OP(SetGlobal, "set_global")
+    CASE_OP(Br, "br")
+    CASE_OP(BrIf, "br_if")
+    default:
+      UNREACHABLE();
+      return "";
+  }
+}
+
+bool IsValidFunctionName(const Vector<const char> &name) {
+  if (name.is_empty()) return false;
+  const char *special_chars = "_.+-*/\\^~=<>!?@#$%&|:'`";
+  for (char c : name) {
+    bool valid_char = (c >= '0' && c <= '9') || (c >= 'a' && c <= 'z') ||
+                      (c >= 'A' && c <= 'Z') || strchr(special_chars, c);
+    if (!valid_char) return false;
+  }
+  return true;
+}
+
+}  // namespace
+
+void wasm::PrintWasmText(const WasmModule *module,
+                         const ModuleWireBytes &wire_bytes, uint32_t func_index,
+                         std::ostream &os,
+                         debug::WasmDisassembly::OffsetTable *offset_table) {
+  DCHECK_NOT_NULL(module);
+  DCHECK_GT(module->functions.size(), func_index);
+  const WasmFunction *fun = &module->functions[func_index];
+
+  AccountingAllocator allocator;
+  Zone zone(&allocator, ZONE_NAME);
+  int line_nr = 0;
+  int control_depth = 1;
+
+  // Print the function signature.
+  os << "func";
+  WasmName fun_name = wire_bytes.GetNameOrNull(fun);
+  if (IsValidFunctionName(fun_name)) {
+    os << " $";
+    os.write(fun_name.start(), fun_name.length());
+  }
+  size_t param_count = fun->sig->parameter_count();
+  if (param_count) {
+    os << " (param";
+    for (size_t i = 0; i < param_count; ++i)
+      os << ' ' << WasmOpcodes::TypeName(fun->sig->GetParam(i));
+    os << ')';
+  }
+  size_t return_count = fun->sig->return_count();
+  if (return_count) {
+    os << " (result";
+    for (size_t i = 0; i < return_count; ++i)
+      os << ' ' << WasmOpcodes::TypeName(fun->sig->GetReturn(i));
+    os << ')';
+  }
+  os << "\n";
+  ++line_nr;
+
+  // Print the local declarations.
+  BodyLocalDecls decls(&zone);
+  Vector<const byte> func_bytes = wire_bytes.module_bytes.SubVector(
+      fun->code_start_offset, fun->code_end_offset);
+  BytecodeIterator i(func_bytes.begin(), func_bytes.end(), &decls);
+  DCHECK_LT(func_bytes.begin(), i.pc());
+  if (!decls.type_list.empty()) {
+    os << "(local";
+    for (const ValueType &v : decls.type_list) {
+      os << ' ' << WasmOpcodes::TypeName(v);
+    }
+    os << ")\n";
+    ++line_nr;
+  }
+
+  for (; i.has_next(); i.next()) {
+    WasmOpcode opcode = i.current();
+    if (opcode == kExprElse || opcode == kExprEnd) --control_depth;
+
+    DCHECK_LE(0, control_depth);
+    const int kMaxIndentation = 64;
+    int indentation = std::min(kMaxIndentation, 2 * control_depth);
+    if (offset_table) {
+      offset_table->push_back(debug::WasmDisassemblyOffsetTableEntry(
+          i.pc_offset(), line_nr, indentation));
+    }
+
+    // 64 whitespaces
+    const char padding[kMaxIndentation + 1] =
+        "                                                                ";
+    os.write(padding, indentation);
+
+    switch (opcode) {
+      case kExprLoop:
+      case kExprIf:
+      case kExprBlock:
+      case kExprTry: {
+        BlockTypeOperand operand(&i, i.pc());
+        os << GetOpName(opcode);
+        for (unsigned i = 0; i < operand.arity; i++) {
+          os << " " << WasmOpcodes::TypeName(operand.read_entry(i));
+        }
+        control_depth++;
+        break;
+      }
+      case kExprBr:
+      case kExprBrIf: {
+        BreakDepthOperand operand(&i, i.pc());
+        os << GetOpName(opcode) << ' ' << operand.depth;
+        break;
+      }
+      case kExprElse:
+        os << "else";
+        control_depth++;
+        break;
+      case kExprEnd:
+        os << "end";
+        break;
+      case kExprBrTable: {
+        BranchTableOperand operand(&i, i.pc());
+        BranchTableIterator iterator(&i, operand);
+        os << "br_table";
+        while (iterator.has_next()) os << ' ' << iterator.next();
+        break;
+      }
+      case kExprCallIndirect: {
+        CallIndirectOperand operand(&i, i.pc());
+        DCHECK_EQ(0, operand.table_index);
+        os << "call_indirect " << operand.index;
+        break;
+      }
+      case kExprCallFunction: {
+        CallFunctionOperand operand(&i, i.pc());
+        os << "call " << operand.index;
+        break;
+      }
+      case kExprGetLocal:
+      case kExprSetLocal:
+      case kExprTeeLocal:
+      case kExprCatch: {
+        LocalIndexOperand operand(&i, i.pc());
+        os << GetOpName(opcode) << ' ' << operand.index;
+        break;
+      }
+      case kExprGetGlobal:
+      case kExprSetGlobal: {
+        GlobalIndexOperand operand(&i, i.pc());
+        os << GetOpName(opcode) << ' ' << operand.index;
+        break;
+      }
+#define CASE_CONST(type, str, cast_type)                           \
+  case kExpr##type##Const: {                                       \
+    Imm##type##Operand operand(&i, i.pc());                        \
+    os << #str ".const " << static_cast<cast_type>(operand.value); \
+    break;                                                         \
+  }
+        CASE_CONST(I32, i32, int32_t)
+        CASE_CONST(I64, i64, int64_t)
+        CASE_CONST(F32, f32, float)
+        CASE_CONST(F64, f64, double)
+
+#define CASE_OPCODE(opcode, _, __) case kExpr##opcode:
+        FOREACH_LOAD_MEM_OPCODE(CASE_OPCODE)
+        FOREACH_STORE_MEM_OPCODE(CASE_OPCODE) {
+          MemoryAccessOperand operand(&i, i.pc(), kMaxUInt32);
+          os << GetOpName(opcode) << " offset=" << operand.offset
+             << " align=" << (1ULL << operand.alignment);
+          break;
+        }
+
+        FOREACH_SIMPLE_OPCODE(CASE_OPCODE)
+      case kExprUnreachable:
+      case kExprNop:
+      case kExprReturn:
+      case kExprMemorySize:
+      case kExprGrowMemory:
+      case kExprDrop:
+      case kExprSelect:
+      case kExprThrow:
+        os << GetOpName(opcode);
+        break;
+
+        // This group is just printed by their internal opcode name, as they
+        // should never be shown to end-users.
+        FOREACH_ASMJS_COMPAT_OPCODE(CASE_OPCODE)
+        // TODO(wasm): Add correct printing for SIMD and atomic opcodes once
+        // they are publicly available.
+        FOREACH_SIMD_0_OPERAND_OPCODE(CASE_OPCODE)
+        FOREACH_SIMD_1_OPERAND_OPCODE(CASE_OPCODE)
+        FOREACH_ATOMIC_OPCODE(CASE_OPCODE)
+        os << WasmOpcodes::OpcodeName(opcode);
+        break;
+
+      default:
+        UNREACHABLE();
+        break;
+    }
+    os << '\n';
+    ++line_nr;
+  }
+  DCHECK_EQ(0, control_depth);
+  DCHECK(i.ok());
+}
diff --git a/deps/v8/src/wasm/wasm-text.h b/deps/v8/src/wasm/wasm-text.h
new file mode 100644
index 0000000000..1608ea9a2d
--- /dev/null
+++ b/deps/v8/src/wasm/wasm-text.h
@@ -0,0 +1,38 @@
+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_WASM_S_EXPR_H_
+#define V8_WASM_S_EXPR_H_
+
+#include <cstdint>
+#include <ostream>
+#include <tuple>
+#include <vector>
+
+namespace v8 {
+
+namespace debug {
+struct WasmDisassemblyOffsetTableEntry;
+}  // namespace debug
+
+namespace internal {
+namespace wasm {
+
+// Forward declaration.
+struct WasmModule;
+struct ModuleWireBytes;
+
+// Generate disassembly according to official text format.
+// Output disassembly to the given output stream, and optionally return an
+// offset table of <byte offset, line, column> via the given pointer.
+void PrintWasmText(
+    const WasmModule *module, const ModuleWireBytes &wire_bytes,
+    uint32_t func_index, std::ostream &os,
+    std::vector<debug::WasmDisassemblyOffsetTableEntry> *offset_table);
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_WASM_S_EXPR_H_