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// Copyright 2015 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_ESCAPE_ANALYSIS_H_
#define V8_COMPILER_ESCAPE_ANALYSIS_H_
#include "src/base/flags.h"
#include "src/compiler/graph.h"
namespace v8 {
namespace internal {
namespace compiler {
// Forward declarations.
class CommonOperatorBuilder;
class EscapeAnalysis;
class VirtualState;
class VirtualObject;
// EscapeStatusAnalysis determines for each allocation whether it escapes.
class EscapeStatusAnalysis {
public:
typedef NodeId Alias;
~EscapeStatusAnalysis();
enum Status {
kUnknown = 0u,
kTracked = 1u << 0,
kEscaped = 1u << 1,
kOnStack = 1u << 2,
kVisited = 1u << 3,
// A node is dangling, if it is a load of some kind, and does not have
// an effect successor.
kDanglingComputed = 1u << 4,
kDangling = 1u << 5,
// A node is is an effect branch point, if it has more than 2 non-dangling
// effect successors.
kBranchPointComputed = 1u << 6,
kBranchPoint = 1u << 7,
kInQueue = 1u << 8
};
typedef base::Flags<Status, uint16_t> StatusFlags;
void RunStatusAnalysis();
bool IsVirtual(Node* node);
bool IsEscaped(Node* node);
bool IsAllocation(Node* node);
bool IsInQueue(NodeId id);
void SetInQueue(NodeId id, bool on_stack);
void DebugPrint();
EscapeStatusAnalysis(EscapeAnalysis* object_analysis, Graph* graph,
Zone* zone);
void EnqueueForStatusAnalysis(Node* node);
bool SetEscaped(Node* node);
bool IsEffectBranchPoint(Node* node);
bool IsDanglingEffectNode(Node* node);
void ResizeStatusVector();
size_t GetStatusVectorSize();
bool IsVirtual(NodeId id);
Graph* graph() const { return graph_; }
Zone* zone() const { return zone_; }
void AssignAliases();
Alias GetAlias(NodeId id) const { return aliases_[id]; }
const ZoneVector<Alias>& GetAliasMap() const { return aliases_; }
Alias AliasCount() const { return next_free_alias_; }
static const Alias kNotReachable;
static const Alias kUntrackable;
bool IsNotReachable(Node* node);
private:
void Process(Node* node);
void ProcessAllocate(Node* node);
void ProcessFinishRegion(Node* node);
void ProcessStoreField(Node* node);
void ProcessStoreElement(Node* node);
bool CheckUsesForEscape(Node* node, bool phi_escaping = false) {
return CheckUsesForEscape(node, node, phi_escaping);
}
bool CheckUsesForEscape(Node* node, Node* rep, bool phi_escaping = false);
void RevisitUses(Node* node);
void RevisitInputs(Node* node);
Alias NextAlias() { return next_free_alias_++; }
bool HasEntry(Node* node);
bool IsAllocationPhi(Node* node);
ZoneVector<Node*> stack_;
EscapeAnalysis* object_analysis_;
Graph* const graph_;
Zone* const zone_;
ZoneVector<StatusFlags> status_;
Alias next_free_alias_;
ZoneVector<Node*> status_stack_;
ZoneVector<Alias> aliases_;
DISALLOW_COPY_AND_ASSIGN(EscapeStatusAnalysis);
};
DEFINE_OPERATORS_FOR_FLAGS(EscapeStatusAnalysis::StatusFlags)
// Forward Declaration.
class MergeCache;
// EscapeObjectAnalysis simulates stores to determine values of loads if
// an object is virtual and eliminated.
class EscapeAnalysis {
public:
using Alias = EscapeStatusAnalysis::Alias;
EscapeAnalysis(Graph* graph, CommonOperatorBuilder* common, Zone* zone);
~EscapeAnalysis();
void Run();
Node* GetReplacement(Node* node);
bool IsVirtual(Node* node);
bool IsEscaped(Node* node);
bool CompareVirtualObjects(Node* left, Node* right);
Node* GetOrCreateObjectState(Node* effect, Node* node);
bool ExistsVirtualAllocate();
private:
void RunObjectAnalysis();
bool Process(Node* node);
void ProcessLoadField(Node* node);
void ProcessStoreField(Node* node);
void ProcessLoadElement(Node* node);
void ProcessStoreElement(Node* node);
void ProcessAllocationUsers(Node* node);
void ProcessAllocation(Node* node);
void ProcessFinishRegion(Node* node);
void ProcessCall(Node* node);
void ProcessStart(Node* node);
bool ProcessEffectPhi(Node* node);
void ProcessLoadFromPhi(int offset, Node* from, Node* node,
VirtualState* states);
void ForwardVirtualState(Node* node);
int OffsetFromAccess(Node* node);
VirtualState* CopyForModificationAt(VirtualState* state, Node* node);
VirtualObject* CopyForModificationAt(VirtualObject* obj, VirtualState* state,
Node* node);
VirtualObject* GetVirtualObject(Node* at, NodeId id);
bool SetEscaped(Node* node);
Node* replacement(NodeId id);
Node* replacement(Node* node);
Node* ResolveReplacement(Node* node);
Node* GetReplacement(NodeId id);
bool SetReplacement(Node* node, Node* rep);
bool UpdateReplacement(VirtualState* state, Node* node, Node* rep);
VirtualObject* GetVirtualObject(VirtualState* state, Node* node);
void DebugPrint();
void DebugPrintState(VirtualState* state);
void DebugPrintObject(VirtualObject* state, Alias id);
Graph* graph() const { return status_analysis_.graph(); }
Zone* zone() const { return status_analysis_.zone(); }
CommonOperatorBuilder* common() const { return common_; }
bool IsEffectBranchPoint(Node* node) {
return status_analysis_.IsEffectBranchPoint(node);
}
bool IsDanglingEffectNode(Node* node) {
return status_analysis_.IsDanglingEffectNode(node);
}
bool IsNotReachable(Node* node) {
return status_analysis_.IsNotReachable(node);
}
Alias GetAlias(NodeId id) const { return status_analysis_.GetAlias(id); }
Alias AliasCount() const { return status_analysis_.AliasCount(); }
EscapeStatusAnalysis status_analysis_;
CommonOperatorBuilder* const common_;
ZoneVector<VirtualState*> virtual_states_;
ZoneVector<Node*> replacements_;
MergeCache* cache_;
DISALLOW_COPY_AND_ASSIGN(EscapeAnalysis);
};
} // namespace compiler
} // namespace internal
} // namespace v8
#endif // V8_COMPILER_ESCAPE_ANALYSIS_H_
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