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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
#ifndef jit_ValueNumbering_h
#define jit_ValueNumbering_h
#include "jit/JitAllocPolicy.h"
#include "js/HashTable.h"
namespace js {
namespace jit {
class MDefinition;
class MBasicBlock;
class MIRGraph;
class MPhi;
class MIRGenerator;
class MResumePoint;
class ValueNumberer
// Value numbering data.
class VisibleValues
// Hash policy for ValueSet.
struct ValueHasher
typedef const MDefinition* Lookup;
typedef MDefinition* Key;
static HashNumber hash(Lookup ins);
static bool match(Key k, Lookup l);
static void rekey(Key& k, Key newKey);
typedef HashSet<MDefinition*, ValueHasher, JitAllocPolicy> ValueSet;
ValueSet set_; // Set of visible values
explicit VisibleValues(TempAllocator& alloc);
bool init();
typedef ValueSet::Ptr Ptr;
typedef ValueSet::AddPtr AddPtr;
Ptr findLeader(const MDefinition* def) const;
AddPtr findLeaderForAdd(MDefinition* def);
bool add(AddPtr p, MDefinition* def);
void overwrite(AddPtr p, MDefinition* def);
void forget(const MDefinition* def);
void clear();
#ifdef DEBUG
bool has(const MDefinition* def) const;
typedef Vector<MBasicBlock*, 4, JitAllocPolicy> BlockWorklist;
typedef Vector<MDefinition*, 4, JitAllocPolicy> DefWorklist;
MIRGenerator* const mir_;
MIRGraph& graph_;
VisibleValues values_; // Numbered values
DefWorklist deadDefs_; // Worklist for deleting values
BlockWorklist remainingBlocks_; // Blocks remaining with fewer preds
MDefinition* nextDef_; // The next definition; don't discard
size_t totalNumVisited_; // The number of blocks visited
bool rerun_; // Should we run another GVN iteration?
bool blocksRemoved_; // Have any blocks been removed?
bool updateAliasAnalysis_; // Do we care about AliasAnalysis?
bool dependenciesBroken_; // Have we broken AliasAnalysis?
enum UseRemovedOption {
bool handleUseReleased(MDefinition* def, UseRemovedOption useRemovedOption);
bool discardDefsRecursively(MDefinition* def);
bool releaseResumePointOperands(MResumePoint* resume);
bool releaseAndRemovePhiOperands(MPhi* phi);
bool releaseOperands(MDefinition* def);
bool discardDef(MDefinition* def);
bool processDeadDefs();
bool fixupOSROnlyLoop(MBasicBlock* block, MBasicBlock* backedge);
bool removePredecessorAndDoDCE(MBasicBlock* block, MBasicBlock* pred, size_t predIndex);
bool removePredecessorAndCleanUp(MBasicBlock* block, MBasicBlock* pred);
MDefinition* simplified(MDefinition* def) const;
MDefinition* leader(MDefinition* def);
bool hasLeader(const MPhi* phi, const MBasicBlock* phiBlock) const;
bool loopHasOptimizablePhi(MBasicBlock* header) const;
bool visitDefinition(MDefinition* def);
bool visitControlInstruction(MBasicBlock* block, const MBasicBlock* root);
bool visitUnreachableBlock(MBasicBlock* block);
bool visitBlock(MBasicBlock* block, const MBasicBlock* root);
bool visitDominatorTree(MBasicBlock* root);
bool visitGraph();
ValueNumberer(MIRGenerator* mir, MIRGraph& graph);
bool init();
enum UpdateAliasAnalysisFlag {
// Optimize the graph, performing expression simplification and
// canonicalization, eliminating statically fully-redundant expressions,
// deleting dead instructions, and removing unreachable blocks.
bool run(UpdateAliasAnalysisFlag updateAliasAnalysis);
} // namespace jit
} // namespace js
#endif /* jit_ValueNumbering_h */