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diff --git a/deps/v8/src/compiler/memory-lowering.h b/deps/v8/src/compiler/memory-lowering.h
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+++ b/deps/v8/src/compiler/memory-lowering.h
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+// Copyright 2019 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_COMPILER_MEMORY_LOWERING_H_
+#define V8_COMPILER_MEMORY_LOWERING_H_
+
+#include "src/compiler/graph-assembler.h"
+#include "src/compiler/graph-reducer.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+// Forward declarations.
+class CommonOperatorBuilder;
+struct ElementAccess;
+class Graph;
+class JSGraph;
+class MachineOperatorBuilder;
+class Node;
+class Operator;
+
+// Provides operations to lower all simplified memory access and allocation
+// related nodes (i.e. Allocate, LoadField, StoreField and friends) to machine
+// operators.
+class MemoryLowering final : public Reducer {
+ public:
+  enum class AllocationFolding { kDoAllocationFolding, kDontAllocationFolding };
+  class AllocationGroup;
+
+  // An allocation state is propagated on the effect paths through the graph.
+  class AllocationState final : public ZoneObject {
+   public:
+    static AllocationState const* Empty(Zone* zone) {
+      return new (zone) AllocationState();
+    }
+    static AllocationState const* Closed(AllocationGroup* group, Node* effect,
+                                         Zone* zone) {
+      return new (zone) AllocationState(group, effect);
+    }
+    static AllocationState const* Open(AllocationGroup* group, intptr_t size,
+                                       Node* top, Node* effect, Zone* zone) {
+      return new (zone) AllocationState(group, size, top, effect);
+    }
+
+    bool IsYoungGenerationAllocation() const;
+
+    AllocationGroup* group() const { return group_; }
+    Node* top() const { return top_; }
+    Node* effect() const { return effect_; }
+    intptr_t size() const { return size_; }
+
+   private:
+    AllocationState();
+    explicit AllocationState(AllocationGroup* group, Node* effect);
+    AllocationState(AllocationGroup* group, intptr_t size, Node* top,
+                    Node* effect);
+
+    AllocationGroup* const group_;
+    // The upper bound of the combined allocated object size on the current path
+    // (max int if allocation folding is impossible on this path).
+    intptr_t const size_;
+    Node* const top_;
+    Node* const effect_;
+
+    DISALLOW_COPY_AND_ASSIGN(AllocationState);
+  };
+
+  using WriteBarrierAssertFailedCallback = std::function<void(
+      Node* node, Node* object, const char* name, Zone* temp_zone)>;
+
+  MemoryLowering(
+      JSGraph* jsgraph, Zone* zone, PoisoningMitigationLevel poisoning_level,
+      AllocationFolding allocation_folding =
+          AllocationFolding::kDontAllocationFolding,
+      WriteBarrierAssertFailedCallback callback = [](Node*, Node*, const char*,
+                                                     Zone*) { UNREACHABLE(); },
+      const char* function_debug_name = nullptr);
+  ~MemoryLowering() = default;
+
+  const char* reducer_name() const override { return "MemoryReducer"; }
+
+  // Perform memory lowering reduction on the given Node.
+  Reduction Reduce(Node* node) override;
+
+  // Specific reducers for each optype to enable keeping track of
+  // AllocationState by the MemoryOptimizer.
+  Reduction ReduceAllocateRaw(Node* node, AllocationType allocation_type,
+                              AllowLargeObjects allow_large_objects,
+                              AllocationState const** state);
+  Reduction ReduceLoadFromObject(Node* node);
+  Reduction ReduceLoadElement(Node* node);
+  Reduction ReduceLoadField(Node* node);
+  Reduction ReduceStoreToObject(Node* node,
+                                AllocationState const* state = nullptr);
+  Reduction ReduceStoreElement(Node* node,
+                               AllocationState const* state = nullptr);
+  Reduction ReduceStoreField(Node* node,
+                             AllocationState const* state = nullptr);
+  Reduction ReduceStore(Node* node, AllocationState const* state = nullptr);
+
+ private:
+  Reduction ReduceAllocateRaw(Node* node);
+  WriteBarrierKind ComputeWriteBarrierKind(Node* node, Node* object,
+                                           Node* value,
+                                           AllocationState const* state,
+                                           WriteBarrierKind);
+  Node* ComputeIndex(ElementAccess const& access, Node* node);
+  bool NeedsPoisoning(LoadSensitivity load_sensitivity) const;
+
+  Graph* graph() const;
+  Isolate* isolate() const;
+  Zone* zone() const { return zone_; }
+  JSGraph* jsgraph() const { return jsgraph_; }
+  CommonOperatorBuilder* common() const;
+  MachineOperatorBuilder* machine() const;
+  GraphAssembler* gasm() { return &graph_assembler_; }
+
+  SetOncePointer<const Operator> allocate_operator_;
+  JSGraph* const jsgraph_;
+  Zone* zone_;
+  GraphAssembler graph_assembler_;
+  AllocationFolding allocation_folding_;
+  PoisoningMitigationLevel poisoning_level_;
+  WriteBarrierAssertFailedCallback write_barrier_assert_failed_;
+  const char* function_debug_name_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(MemoryLowering);
+};
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_MEMORY_LOWERING_H_