| Index: src/hydrogen-flow-engine.h
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| diff --git a/src/hydrogen-flow-engine.h b/src/hydrogen-flow-engine.h
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| deleted file mode 100644
|
| index 9735ea811aee9712a0f439d62f3651a91ec5b3b0..0000000000000000000000000000000000000000
|
| --- a/src/hydrogen-flow-engine.h
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| +++ /dev/null
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| @@ -1,220 +0,0 @@
|
| -// Copyright 2013 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_HYDROGEN_FLOW_ENGINE_H_
|
| -#define V8_HYDROGEN_FLOW_ENGINE_H_
|
| -
|
| -#include "src/hydrogen.h"
|
| -#include "src/hydrogen-instructions.h"
|
| -#include "src/zone.h"
|
| -
|
| -namespace v8 {
|
| -namespace internal {
|
| -
|
| -// An example implementation of effects that doesn't collect anything.
|
| -class NoEffects : public ZoneObject {
|
| - public:
|
| - explicit NoEffects(Zone* zone) { }
|
| -
|
| - inline bool Disabled() {
|
| - return true; // Nothing to do.
|
| - }
|
| - template <class State>
|
| - inline void Apply(State* state) {
|
| - // do nothing.
|
| - }
|
| - inline void Process(HInstruction* value, Zone* zone) {
|
| - // do nothing.
|
| - }
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| - inline void Union(NoEffects* other, Zone* zone) {
|
| - // do nothing.
|
| - }
|
| -};
|
| -
|
| -
|
| -// An example implementation of state that doesn't track anything.
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| -class NoState {
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| - public:
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| - inline NoState* Copy(HBasicBlock* succ, Zone* zone) {
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| - return this;
|
| - }
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| - inline NoState* Process(HInstruction* value, Zone* zone) {
|
| - return this;
|
| - }
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| - inline NoState* Merge(HBasicBlock* succ, NoState* other, Zone* zone) {
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| - return this;
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| - }
|
| -};
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| -
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| -
|
| -// This class implements an engine that can drive flow-sensitive analyses
|
| -// over a graph of basic blocks, either one block at a time (local analysis)
|
| -// or over the entire graph (global analysis). The flow engine is parameterized
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| -// by the type of the state and the effects collected while walking over the
|
| -// graph.
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| -//
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| -// The "State" collects which facts are known while passing over instructions
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| -// in control flow order, and the "Effects" collect summary information about
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| -// which facts could be invalidated on other control flow paths. The effects
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| -// are necessary to correctly handle loops in the control flow graph without
|
| -// doing a fixed-point iteration. Thus the flow engine is guaranteed to visit
|
| -// each block at most twice; once for state, and optionally once for effects.
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| -//
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| -// The flow engine requires the State and Effects classes to implement methods
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| -// like the example NoState and NoEffects above. It's not necessary to provide
|
| -// an effects implementation for local analysis.
|
| -template <class State, class Effects>
|
| -class HFlowEngine {
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| - public:
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| - HFlowEngine(HGraph* graph, Zone* zone)
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| - : graph_(graph),
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| - zone_(zone),
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| -#if DEBUG
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| - pred_counts_(graph->blocks()->length(), zone),
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| -#endif
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| - block_states_(graph->blocks()->length(), zone),
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| - loop_effects_(graph->blocks()->length(), zone) {
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| - loop_effects_.AddBlock(NULL, graph_->blocks()->length(), zone);
|
| - }
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| -
|
| - // Local analysis. Iterates over the instructions in the given block.
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| - State* AnalyzeOneBlock(HBasicBlock* block, State* state) {
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| - // Go through all instructions of the current block, updating the state.
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| - for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
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| - state = state->Process(it.Current(), zone_);
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| - }
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| - return state;
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| - }
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| -
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| - // Global analysis. Iterates over all blocks that are dominated by the given
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| - // block, starting with the initial state. Computes effects for nested loops.
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| - void AnalyzeDominatedBlocks(HBasicBlock* root, State* initial) {
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| - InitializeStates();
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| - SetStateAt(root, initial);
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| -
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| - // Iterate all dominated blocks starting from the given start block.
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| - for (int i = root->block_id(); i < graph_->blocks()->length(); i++) {
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| - HBasicBlock* block = graph_->blocks()->at(i);
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| -
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| - // Skip blocks not dominated by the root node.
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| - if (SkipNonDominatedBlock(root, block)) continue;
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| - State* state = State::Finish(StateAt(block), block, zone_);
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| -
|
| - if (block->IsReachable()) {
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| - DCHECK(state != NULL);
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| - if (block->IsLoopHeader()) {
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| - // Apply loop effects before analyzing loop body.
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| - ComputeLoopEffects(block)->Apply(state);
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| - } else {
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| - // Must have visited all predecessors before this block.
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| - CheckPredecessorCount(block);
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| - }
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| -
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| - // Go through all instructions of the current block, updating the state.
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| - for (HInstructionIterator it(block); !it.Done(); it.Advance()) {
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| - state = state->Process(it.Current(), zone_);
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| - }
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| - }
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| -
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| - // Propagate the block state forward to all successor blocks.
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| - int max = block->end()->SuccessorCount();
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| - for (int i = 0; i < max; i++) {
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| - HBasicBlock* succ = block->end()->SuccessorAt(i);
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| - IncrementPredecessorCount(succ);
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| -
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| - if (max == 1 && succ->predecessors()->length() == 1) {
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| - // Optimization: successor can inherit this state.
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| - SetStateAt(succ, state);
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| - } else {
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| - // Merge the current state with the state already at the successor.
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| - SetStateAt(succ,
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| - State::Merge(StateAt(succ), succ, state, block, zone_));
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| - }
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| - }
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| - }
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| - }
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| -
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| - private:
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| - // Computes and caches the loop effects for the loop which has the given
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| - // block as its loop header.
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| - Effects* ComputeLoopEffects(HBasicBlock* block) {
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| - DCHECK(block->IsLoopHeader());
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| - Effects* effects = loop_effects_[block->block_id()];
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| - if (effects != NULL) return effects; // Already analyzed this loop.
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| -
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| - effects = new(zone_) Effects(zone_);
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| - loop_effects_[block->block_id()] = effects;
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| - if (effects->Disabled()) return effects; // No effects for this analysis.
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| -
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| - HLoopInformation* loop = block->loop_information();
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| - int end = loop->GetLastBackEdge()->block_id();
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| - // Process the blocks between the header and the end.
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| - for (int i = block->block_id(); i <= end; i++) {
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| - HBasicBlock* member = graph_->blocks()->at(i);
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| - if (i != block->block_id() && member->IsLoopHeader()) {
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| - // Recursively compute and cache the effects of the nested loop.
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| - DCHECK(member->loop_information()->parent_loop() == loop);
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| - Effects* nested = ComputeLoopEffects(member);
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| - effects->Union(nested, zone_);
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| - // Skip the nested loop's blocks.
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| - i = member->loop_information()->GetLastBackEdge()->block_id();
|
| - } else {
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| - // Process all the effects of the block.
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| - if (member->IsUnreachable()) continue;
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| - DCHECK(member->current_loop() == loop);
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| - for (HInstructionIterator it(member); !it.Done(); it.Advance()) {
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| - effects->Process(it.Current(), zone_);
|
| - }
|
| - }
|
| - }
|
| - return effects;
|
| - }
|
| -
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| - inline bool SkipNonDominatedBlock(HBasicBlock* root, HBasicBlock* other) {
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| - if (root->block_id() == 0) return false; // Visit the whole graph.
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| - if (root == other) return false; // Always visit the root.
|
| - return !root->Dominates(other); // Only visit dominated blocks.
|
| - }
|
| -
|
| - inline State* StateAt(HBasicBlock* block) {
|
| - return block_states_.at(block->block_id());
|
| - }
|
| -
|
| - inline void SetStateAt(HBasicBlock* block, State* state) {
|
| - block_states_.Set(block->block_id(), state);
|
| - }
|
| -
|
| - inline void InitializeStates() {
|
| -#if DEBUG
|
| - pred_counts_.Rewind(0);
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| - pred_counts_.AddBlock(0, graph_->blocks()->length(), zone_);
|
| -#endif
|
| - block_states_.Rewind(0);
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| - block_states_.AddBlock(NULL, graph_->blocks()->length(), zone_);
|
| - }
|
| -
|
| - inline void CheckPredecessorCount(HBasicBlock* block) {
|
| - DCHECK(block->predecessors()->length() == pred_counts_[block->block_id()]);
|
| - }
|
| -
|
| - inline void IncrementPredecessorCount(HBasicBlock* block) {
|
| -#if DEBUG
|
| - pred_counts_[block->block_id()]++;
|
| -#endif
|
| - }
|
| -
|
| - HGraph* graph_; // The hydrogen graph.
|
| - Zone* zone_; // Temporary zone.
|
| -#if DEBUG
|
| - ZoneList<int> pred_counts_; // Finished predecessors (by block id).
|
| -#endif
|
| - ZoneList<State*> block_states_; // Block states (by block id).
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| - ZoneList<Effects*> loop_effects_; // Loop effects (by block id).
|
| -};
|
| -
|
| -
|
| -} // namespace internal
|
| -} // namespace v8
|
| -
|
| -#endif // V8_HYDROGEN_FLOW_ENGINE_H_
|
|
|