Index: src/hydrogen-escape-analysis.cc |
diff --git a/src/hydrogen-escape-analysis.cc b/src/hydrogen-escape-analysis.cc |
deleted file mode 100644 |
index 361373719269d35cd9239905ba621a27b97c2dd5..0000000000000000000000000000000000000000 |
--- a/src/hydrogen-escape-analysis.cc |
+++ /dev/null |
@@ -1,329 +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. |
- |
-#include "src/hydrogen-escape-analysis.h" |
- |
-namespace v8 { |
-namespace internal { |
- |
- |
-bool HEscapeAnalysisPhase::HasNoEscapingUses(HValue* value, int size) { |
- for (HUseIterator it(value->uses()); !it.Done(); it.Advance()) { |
- HValue* use = it.value(); |
- if (use->HasEscapingOperandAt(it.index())) { |
- if (FLAG_trace_escape_analysis) { |
- PrintF("#%d (%s) escapes through #%d (%s) @%d\n", value->id(), |
- value->Mnemonic(), use->id(), use->Mnemonic(), it.index()); |
- } |
- return false; |
- } |
- if (use->HasOutOfBoundsAccess(size)) { |
- if (FLAG_trace_escape_analysis) { |
- PrintF("#%d (%s) out of bounds at #%d (%s) @%d\n", value->id(), |
- value->Mnemonic(), use->id(), use->Mnemonic(), it.index()); |
- } |
- return false; |
- } |
- int redefined_index = use->RedefinedOperandIndex(); |
- if (redefined_index == it.index() && !HasNoEscapingUses(use, size)) { |
- if (FLAG_trace_escape_analysis) { |
- PrintF("#%d (%s) escapes redefinition #%d (%s) @%d\n", value->id(), |
- value->Mnemonic(), use->id(), use->Mnemonic(), it.index()); |
- } |
- return false; |
- } |
- } |
- return true; |
-} |
- |
- |
-void HEscapeAnalysisPhase::CollectCapturedValues() { |
- int block_count = graph()->blocks()->length(); |
- for (int i = 0; i < block_count; ++i) { |
- HBasicBlock* block = graph()->blocks()->at(i); |
- for (HInstructionIterator it(block); !it.Done(); it.Advance()) { |
- HInstruction* instr = it.Current(); |
- if (!instr->IsAllocate()) continue; |
- HAllocate* allocate = HAllocate::cast(instr); |
- if (!allocate->size()->IsInteger32Constant()) continue; |
- int size_in_bytes = allocate->size()->GetInteger32Constant(); |
- if (HasNoEscapingUses(instr, size_in_bytes)) { |
- if (FLAG_trace_escape_analysis) { |
- PrintF("#%d (%s) is being captured\n", instr->id(), |
- instr->Mnemonic()); |
- } |
- captured_.Add(instr, zone()); |
- } |
- } |
- } |
-} |
- |
- |
-HCapturedObject* HEscapeAnalysisPhase::NewState(HInstruction* previous) { |
- Zone* zone = graph()->zone(); |
- HCapturedObject* state = |
- new(zone) HCapturedObject(number_of_values_, number_of_objects_, zone); |
- state->InsertAfter(previous); |
- return state; |
-} |
- |
- |
-// Create a new state for replacing HAllocate instructions. |
-HCapturedObject* HEscapeAnalysisPhase::NewStateForAllocation( |
- HInstruction* previous) { |
- HConstant* undefined = graph()->GetConstantUndefined(); |
- HCapturedObject* state = NewState(previous); |
- for (int index = 0; index < number_of_values_; index++) { |
- state->SetOperandAt(index, undefined); |
- } |
- return state; |
-} |
- |
- |
-// Create a new state full of phis for loop header entries. |
-HCapturedObject* HEscapeAnalysisPhase::NewStateForLoopHeader( |
- HInstruction* previous, |
- HCapturedObject* old_state) { |
- HBasicBlock* block = previous->block(); |
- HCapturedObject* state = NewState(previous); |
- for (int index = 0; index < number_of_values_; index++) { |
- HValue* operand = old_state->OperandAt(index); |
- HPhi* phi = NewPhiAndInsert(block, operand, index); |
- state->SetOperandAt(index, phi); |
- } |
- return state; |
-} |
- |
- |
-// Create a new state by copying an existing one. |
-HCapturedObject* HEscapeAnalysisPhase::NewStateCopy( |
- HInstruction* previous, |
- HCapturedObject* old_state) { |
- HCapturedObject* state = NewState(previous); |
- for (int index = 0; index < number_of_values_; index++) { |
- HValue* operand = old_state->OperandAt(index); |
- state->SetOperandAt(index, operand); |
- } |
- return state; |
-} |
- |
- |
-// Insert a newly created phi into the given block and fill all incoming |
-// edges with the given value. |
-HPhi* HEscapeAnalysisPhase::NewPhiAndInsert(HBasicBlock* block, |
- HValue* incoming_value, |
- int index) { |
- Zone* zone = graph()->zone(); |
- HPhi* phi = new(zone) HPhi(HPhi::kInvalidMergedIndex, zone); |
- for (int i = 0; i < block->predecessors()->length(); i++) { |
- phi->AddInput(incoming_value); |
- } |
- block->AddPhi(phi); |
- return phi; |
-} |
- |
- |
-// Insert a newly created value check as a replacement for map checks. |
-HValue* HEscapeAnalysisPhase::NewMapCheckAndInsert(HCapturedObject* state, |
- HCheckMaps* mapcheck) { |
- Zone* zone = graph()->zone(); |
- HValue* value = state->map_value(); |
- // TODO(mstarzinger): This will narrow a map check against a set of maps |
- // down to the first element in the set. Revisit and fix this. |
- HCheckValue* check = HCheckValue::New(graph()->isolate(), zone, NULL, value, |
- mapcheck->maps()->at(0), false); |
- check->InsertBefore(mapcheck); |
- return check; |
-} |
- |
- |
-// Replace a field load with a given value, forcing Smi representation if |
-// necessary. |
-HValue* HEscapeAnalysisPhase::NewLoadReplacement( |
- HLoadNamedField* load, HValue* load_value) { |
- HValue* replacement = load_value; |
- Representation representation = load->representation(); |
- if (representation.IsSmiOrInteger32() || representation.IsDouble()) { |
- Zone* zone = graph()->zone(); |
- HInstruction* new_instr = HForceRepresentation::New( |
- graph()->isolate(), zone, NULL, load_value, representation); |
- new_instr->InsertAfter(load); |
- replacement = new_instr; |
- } |
- return replacement; |
-} |
- |
- |
-// Performs a forward data-flow analysis of all loads and stores on the |
-// given captured allocation. This uses a reverse post-order iteration |
-// over affected basic blocks. All non-escaping instructions are handled |
-// and replaced during the analysis. |
-void HEscapeAnalysisPhase::AnalyzeDataFlow(HInstruction* allocate) { |
- HBasicBlock* allocate_block = allocate->block(); |
- block_states_.AddBlock(NULL, graph()->blocks()->length(), zone()); |
- |
- // Iterate all blocks starting with the allocation block, since the |
- // allocation cannot dominate blocks that come before. |
- int start = allocate_block->block_id(); |
- for (int i = start; i < graph()->blocks()->length(); i++) { |
- HBasicBlock* block = graph()->blocks()->at(i); |
- HCapturedObject* state = StateAt(block); |
- |
- // Skip blocks that are not dominated by the captured allocation. |
- if (!allocate_block->Dominates(block) && allocate_block != block) continue; |
- if (FLAG_trace_escape_analysis) { |
- PrintF("Analyzing data-flow in B%d\n", block->block_id()); |
- } |
- |
- // Go through all instructions of the current block. |
- for (HInstructionIterator it(block); !it.Done(); it.Advance()) { |
- HInstruction* instr = it.Current(); |
- switch (instr->opcode()) { |
- case HValue::kAllocate: { |
- if (instr != allocate) continue; |
- state = NewStateForAllocation(allocate); |
- break; |
- } |
- case HValue::kLoadNamedField: { |
- HLoadNamedField* load = HLoadNamedField::cast(instr); |
- int index = load->access().offset() / kPointerSize; |
- if (load->object() != allocate) continue; |
- DCHECK(load->access().IsInobject()); |
- HValue* replacement = |
- NewLoadReplacement(load, state->OperandAt(index)); |
- load->DeleteAndReplaceWith(replacement); |
- if (FLAG_trace_escape_analysis) { |
- PrintF("Replacing load #%d with #%d (%s)\n", load->id(), |
- replacement->id(), replacement->Mnemonic()); |
- } |
- break; |
- } |
- case HValue::kStoreNamedField: { |
- HStoreNamedField* store = HStoreNamedField::cast(instr); |
- int index = store->access().offset() / kPointerSize; |
- if (store->object() != allocate) continue; |
- DCHECK(store->access().IsInobject()); |
- state = NewStateCopy(store->previous(), state); |
- state->SetOperandAt(index, store->value()); |
- if (store->has_transition()) { |
- state->SetOperandAt(0, store->transition()); |
- } |
- if (store->HasObservableSideEffects()) { |
- state->ReuseSideEffectsFromStore(store); |
- } |
- store->DeleteAndReplaceWith(store->ActualValue()); |
- if (FLAG_trace_escape_analysis) { |
- PrintF("Replacing store #%d%s\n", instr->id(), |
- store->has_transition() ? " (with transition)" : ""); |
- } |
- break; |
- } |
- case HValue::kArgumentsObject: |
- case HValue::kCapturedObject: |
- case HValue::kSimulate: { |
- for (int i = 0; i < instr->OperandCount(); i++) { |
- if (instr->OperandAt(i) != allocate) continue; |
- instr->SetOperandAt(i, state); |
- } |
- break; |
- } |
- case HValue::kCheckHeapObject: { |
- HCheckHeapObject* check = HCheckHeapObject::cast(instr); |
- if (check->value() != allocate) continue; |
- check->DeleteAndReplaceWith(check->ActualValue()); |
- break; |
- } |
- case HValue::kCheckMaps: { |
- HCheckMaps* mapcheck = HCheckMaps::cast(instr); |
- if (mapcheck->value() != allocate) continue; |
- NewMapCheckAndInsert(state, mapcheck); |
- mapcheck->DeleteAndReplaceWith(mapcheck->ActualValue()); |
- break; |
- } |
- default: |
- // Nothing to see here, move along ... |
- break; |
- } |
- } |
- |
- // Propagate the block state forward to all successor blocks. |
- for (int i = 0; i < block->end()->SuccessorCount(); i++) { |
- HBasicBlock* succ = block->end()->SuccessorAt(i); |
- if (!allocate_block->Dominates(succ)) continue; |
- if (succ->predecessors()->length() == 1) { |
- // Case 1: This is the only predecessor, just reuse state. |
- SetStateAt(succ, state); |
- } else if (StateAt(succ) == NULL && succ->IsLoopHeader()) { |
- // Case 2: This is a state that enters a loop header, be |
- // pessimistic about loop headers, add phis for all values. |
- SetStateAt(succ, NewStateForLoopHeader(succ->first(), state)); |
- } else if (StateAt(succ) == NULL) { |
- // Case 3: This is the first state propagated forward to the |
- // successor, leave a copy of the current state. |
- SetStateAt(succ, NewStateCopy(succ->first(), state)); |
- } else { |
- // Case 4: This is a state that needs merging with previously |
- // propagated states, potentially introducing new phis lazily or |
- // adding values to existing phis. |
- HCapturedObject* succ_state = StateAt(succ); |
- for (int index = 0; index < number_of_values_; index++) { |
- HValue* operand = state->OperandAt(index); |
- HValue* succ_operand = succ_state->OperandAt(index); |
- if (succ_operand->IsPhi() && succ_operand->block() == succ) { |
- // Phi already exists, add operand. |
- HPhi* phi = HPhi::cast(succ_operand); |
- phi->SetOperandAt(succ->PredecessorIndexOf(block), operand); |
- } else if (succ_operand != operand) { |
- // Phi does not exist, introduce one. |
- HPhi* phi = NewPhiAndInsert(succ, succ_operand, index); |
- phi->SetOperandAt(succ->PredecessorIndexOf(block), operand); |
- succ_state->SetOperandAt(index, phi); |
- } |
- } |
- } |
- } |
- } |
- |
- // All uses have been handled. |
- DCHECK(allocate->HasNoUses()); |
- allocate->DeleteAndReplaceWith(NULL); |
-} |
- |
- |
-void HEscapeAnalysisPhase::PerformScalarReplacement() { |
- for (int i = 0; i < captured_.length(); i++) { |
- HAllocate* allocate = HAllocate::cast(captured_.at(i)); |
- |
- // Compute number of scalar values and start with clean slate. |
- int size_in_bytes = allocate->size()->GetInteger32Constant(); |
- number_of_values_ = size_in_bytes / kPointerSize; |
- number_of_objects_++; |
- block_states_.Rewind(0); |
- |
- // Perform actual analysis step. |
- AnalyzeDataFlow(allocate); |
- |
- cumulative_values_ += number_of_values_; |
- DCHECK(allocate->HasNoUses()); |
- DCHECK(!allocate->IsLinked()); |
- } |
-} |
- |
- |
-void HEscapeAnalysisPhase::Run() { |
- // TODO(mstarzinger): We disable escape analysis with OSR for now, because |
- // spill slots might be uninitialized. Needs investigation. |
- if (graph()->has_osr()) return; |
- int max_fixpoint_iteration_count = FLAG_escape_analysis_iterations; |
- for (int i = 0; i < max_fixpoint_iteration_count; i++) { |
- CollectCapturedValues(); |
- if (captured_.is_empty()) break; |
- PerformScalarReplacement(); |
- captured_.Rewind(0); |
- } |
-} |
- |
- |
-} // namespace internal |
-} // namespace v8 |