1 files changed, 79 insertions, 0 deletions
diff --git a/deps/v8/src/wasm/jump-table-assembler.h b/deps/v8/src/wasm/jump-table-assembler.h
new file mode 100644
index 0000000000..1ef1a82f41
--- /dev/null
+++ b/deps/v8/src/wasm/jump-table-assembler.h
@@ -0,0 +1,79 @@
+// Copyright 2018 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_JUMP_TABLE_ASSEMBLER_H_
+#define V8_WASM_JUMP_TABLE_ASSEMBLER_H_
+
+#include "src/macro-assembler.h"
+#include "src/wasm/wasm-code-manager.h"
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+class JumpTableAssembler : public TurboAssembler {
+ public:
+  // Instantiate a {JumpTableAssembler} for patching.
+  explicit JumpTableAssembler(Address slot_addr, int size = 256)
+      : TurboAssembler(nullptr, JumpTableAssemblerOptions(),
+                       reinterpret_cast<void*>(slot_addr), size,
+                       CodeObjectRequired::kNo) {}
+
+#if V8_TARGET_ARCH_X64
+  static constexpr int kJumpTableSlotSize = 18;
+#elif V8_TARGET_ARCH_IA32
+  static constexpr int kJumpTableSlotSize = 10;
+#elif V8_TARGET_ARCH_ARM
+  static constexpr int kJumpTableSlotSize = 5 * kInstrSize;
+#elif V8_TARGET_ARCH_ARM64
+  static constexpr int kJumpTableSlotSize = 3 * kInstructionSize;
+#elif V8_TARGET_ARCH_S390X
+  static constexpr int kJumpTableSlotSize = 20;
+#elif V8_TARGET_ARCH_S390
+  static constexpr int kJumpTableSlotSize = 14;
+#elif V8_TARGET_ARCH_PPC64
+  static constexpr int kJumpTableSlotSize = 48;
+#elif V8_TARGET_ARCH_PPC
+  static constexpr int kJumpTableSlotSize = 24;
+#elif V8_TARGET_ARCH_MIPS
+  static constexpr int kJumpTableSlotSize = 6 * kInstrSize;
+#elif V8_TARGET_ARCH_MIPS64
+  static constexpr int kJumpTableSlotSize = 8 * kInstrSize;
+#else
+  static constexpr int kJumpTableSlotSize = 1;
+#endif
+
+  // {JumpTableAssembler} is never used during snapshot generation, and its code
+  // must be independent of the code range of any isolate anyway. Just ensure
+  // that no relocation information is recorded, there is no buffer to store it
+  // since it is instantiated in patching mode in existing code directly.
+  static AssemblerOptions JumpTableAssemblerOptions() {
+    AssemblerOptions options;
+    options.disable_reloc_info_for_patching = true;
+    return options;
+  }
+
+  void EmitLazyCompileJumpSlot(uint32_t func_index,
+                               Address lazy_compile_target);
+
+  void EmitJumpSlot(Address target);
+
+  void NopBytes(int bytes);
+
+  static void PatchJumpTableSlot(Address slot, Address new_target,
+                                 WasmCode::FlushICache flush_i_cache) {
+    JumpTableAssembler jsasm(slot);
+    jsasm.EmitJumpSlot(new_target);
+    jsasm.NopBytes(kJumpTableSlotSize - jsasm.pc_offset());
+    if (flush_i_cache) {
+      Assembler::FlushICache(slot, kJumpTableSlotSize);
+    }
+  }
+};
+
+}  // namespace wasm
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_WASM_JUMP_TABLE_ASSEMBLER_H_