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// 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/compiler/graph-assembler.h"
#include "src/zone/zone-containers.h"
namespace v8 {
namespace internal {
namespace compiler {
// Forward declarations.
class CommonOperatorBuilder;
struct ElementAccess;
class Graph;
class JSGraph;
class MachineOperatorBuilder;
class Node;
class Operator;
// NodeIds are identifying numbers for nodes that can be used to index auxiliary
// out-of-line data associated with each node.
typedef uint32_t NodeId;
// Lowers all simplified memory access and allocation related nodes (i.e.
// Allocate, LoadField, StoreField and friends) to machine operators.
// Performs allocation folding and store write barrier elimination
// implicitly.
class MemoryOptimizer final {
MemoryOptimizer(JSGraph* jsgraph, Zone* zone);
~MemoryOptimizer() {}
void Optimize();
// An allocation group represents a set of allocations that have been folded
// together.
class AllocationGroup final : public ZoneObject {
AllocationGroup(Node* node, PretenureFlag pretenure, Zone* zone);
AllocationGroup(Node* node, PretenureFlag pretenure, Node* size,
Zone* zone);
~AllocationGroup() {}
void Add(Node* object);
bool Contains(Node* object) const;
bool IsNewSpaceAllocation() const { return pretenure() == NOT_TENURED; }
PretenureFlag pretenure() const { return pretenure_; }
Node* size() const { return size_; }
ZoneSet<NodeId> node_ids_;
PretenureFlag const pretenure_;
Node* const size_;
// An allocation state is propagated on the effect paths through the graph.
class AllocationState final : public ZoneObject {
static AllocationState const* Empty(Zone* zone) {
return new (zone) AllocationState();
static AllocationState const* Closed(AllocationGroup* group, Zone* zone) {
return new (zone) AllocationState(group);
static AllocationState const* Open(AllocationGroup* group, int size,
Node* top, Zone* zone) {
return new (zone) AllocationState(group, size, top);
bool IsNewSpaceAllocation() const;
AllocationGroup* group() const { return group_; }
Node* top() const { return top_; }
int size() const { return size_; }
explicit AllocationState(AllocationGroup* group);
AllocationState(AllocationGroup* group, int size, Node* top);
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).
int const size_;
Node* const top_;
// An array of allocation states used to collect states on merges.
typedef ZoneVector<AllocationState const*> AllocationStates;
// We thread through tokens to represent the current state on a given effect
// path through the graph.
struct Token {
Node* node;
AllocationState const* state;
void VisitNode(Node*, AllocationState const*);
void VisitAllocateRaw(Node*, AllocationState const*);
void VisitCall(Node*, AllocationState const*);
void VisitCallWithCallerSavedRegisters(Node*, AllocationState const*);
void VisitLoadElement(Node*, AllocationState const*);
void VisitLoadField(Node*, AllocationState const*);
void VisitStoreElement(Node*, AllocationState const*);
void VisitStoreField(Node*, AllocationState const*);
void VisitOtherEffect(Node*, AllocationState const*);
Node* ComputeIndex(ElementAccess const&, Node*);
WriteBarrierKind ComputeWriteBarrierKind(Node* object,
AllocationState const* state,
AllocationState const* MergeStates(AllocationStates const& states);
void EnqueueMerge(Node*, int, AllocationState const*);
void EnqueueUses(Node*, AllocationState const*);
void EnqueueUse(Node*, int, AllocationState const*);
AllocationState const* empty_state() const { return empty_state_; }
Graph* graph() const;
Isolate* isolate() const;
JSGraph* jsgraph() const { return jsgraph_; }
CommonOperatorBuilder* common() const;
MachineOperatorBuilder* machine() const;
Zone* zone() const { return zone_; }
GraphAssembler* gasm() { return &graph_assembler_; }
SetOncePointer<const Operator> allocate_operator_;
JSGraph* const jsgraph_;
AllocationState const* const empty_state_;
ZoneMap<NodeId, AllocationStates> pending_;
ZoneQueue<Token> tokens_;
Zone* const zone_;
GraphAssembler graph_assembler_;
} // namespace compiler
} // namespace internal
} // namespace v8