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Refactor Hydrogen environment liveness analysis into an HPhase.

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Rename EnvironmentSlotLivenessAnalyzer to HEnvironmentLivenessAnalysisPhase,
following naming scheme suggested by danno@chromium.org in
https://codereview.chromium.org/17458002

The environment slot liveness analysis now uses the phase zone for
all its allocations.

Depends on https://codereview.chromium.org/18034003

R=danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/17587008

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@15356 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
bmeurer@chromium.org 2013-06-27 13:15:10 +00:00
parent 32f5e099d4
commit 2f81a79d5a
3 changed files with 67 additions and 82 deletions
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119
src/hydrogen-environment-liveness.cc
View File

@ -33,64 +33,56 @@ namespace v8 {
namespace internal {
EnvironmentSlotLivenessAnalyzer::EnvironmentSlotLivenessAnalyzer(
HEnvironmentLivenessAnalysisPhase::HEnvironmentLivenessAnalysisPhase(
HGraph* graph)
: graph_(graph),
zone_(graph->isolate()),
: HPhase("H_Environment liveness analysis", graph),
block_count_(graph->blocks()->length()),
maximum_environment_size_(graph->maximum_environment_size()),
live_at_block_start_(block_count_, zone()),
first_simulate_(block_count_, zone()),
first_simulate_invalid_for_index_(block_count_, zone()),
markers_(maximum_environment_size_, zone()),
collect_markers_(true),
last_simulate_(NULL) {
if (maximum_environment_size_ == 0) return;
live_at_block_start_ =
new(zone()) ZoneList<BitVector*>(block_count_, zone());
first_simulate_ = new(zone()) ZoneList<HSimulate*>(block_count_, zone());
first_simulate_invalid_for_index_ =
new(zone()) ZoneList<BitVector*>(block_count_, zone());
markers_ = new(zone())
ZoneList<HEnvironmentMarker*>(maximum_environment_size_, zone());
went_live_since_last_simulate_ =
new(zone()) BitVector(maximum_environment_size_, zone());
last_simulate_(NULL),
went_live_since_last_simulate_(maximum_environment_size_, zone()) {
ASSERT(maximum_environment_size_ > 0);
for (int i = 0; i < block_count_; ++i) {
live_at_block_start_->Add(
live_at_block_start_.Add(
new(zone()) BitVector(maximum_environment_size_, zone()), zone());
first_simulate_->Add(NULL, zone());
first_simulate_invalid_for_index_->Add(
first_simulate_.Add(NULL, zone());
first_simulate_invalid_for_index_.Add(
new(zone()) BitVector(maximum_environment_size_, zone()), zone());
}
}
void EnvironmentSlotLivenessAnalyzer::ZapEnvironmentSlot(int index,
HSimulate* simulate) {
void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlot(
int index, HSimulate* simulate) {
int operand_index = simulate->ToOperandIndex(index);
if (operand_index == -1) {
simulate->AddAssignedValue(index, graph_->GetConstantUndefined());
simulate->AddAssignedValue(index, graph()->GetConstantUndefined());
} else {
simulate->SetOperandAt(operand_index, graph_->GetConstantUndefined());
simulate->SetOperandAt(operand_index, graph()->GetConstantUndefined());
}
}
void EnvironmentSlotLivenessAnalyzer::ZapEnvironmentSlotsInSuccessors(
HBasicBlock* block,
BitVector* live) {
void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsInSuccessors(
HBasicBlock* block, BitVector* live) {
// When a value is live in successor A but dead in B, we must
// explicitly zap it in B.
for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) {
HBasicBlock* successor = it.Current();
int successor_id = successor->block_id();
BitVector* live_in_successor = live_at_block_start_->at(successor_id);
BitVector* live_in_successor = live_at_block_start_[successor_id];
if (live_in_successor->Equals(*live)) continue;
for (int i = 0; i < live->length(); ++i) {
if (!live->Contains(i)) continue;
if (live_in_successor->Contains(i)) continue;
if (first_simulate_invalid_for_index_->at(successor_id)->Contains(i)) {
if (first_simulate_invalid_for_index_.at(successor_id)->Contains(i)) {
continue;
}
HSimulate* simulate = first_simulate_->at(successor_id);
HSimulate* simulate = first_simulate_.at(successor_id);
if (simulate == NULL) continue;
ASSERT(simulate->closure().is_identical_to(
block->last_environment()->closure()));
@ -100,7 +92,7 @@ void EnvironmentSlotLivenessAnalyzer::ZapEnvironmentSlotsInSuccessors(
}
void EnvironmentSlotLivenessAnalyzer::ZapEnvironmentSlotsForInstruction(
void HEnvironmentLivenessAnalysisPhase::ZapEnvironmentSlotsForInstruction(
HEnvironmentMarker* marker) {
if (!marker->CheckFlag(HValue::kEndsLiveRange)) return;
HSimulate* simulate = marker->next_simulate();
@ -111,18 +103,18 @@ void EnvironmentSlotLivenessAnalyzer::ZapEnvironmentSlotsForInstruction(
}
void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtBlockEnd(
void HEnvironmentLivenessAnalysisPhase::UpdateLivenessAtBlockEnd(
HBasicBlock* block,
BitVector* live) {
// Liveness at the end of each block: union of liveness in successors.
live->Clear();
for (HSuccessorIterator it(block->end()); !it.Done(); it.Advance()) {
live->Union(*live_at_block_start_->at(it.Current()->block_id()));
live->Union(*live_at_block_start_[it.Current()->block_id()]);
}
}
void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
void HEnvironmentLivenessAnalysisPhase::UpdateLivenessAtInstruction(
HInstruction* instr,
BitVector* live) {
switch (instr->opcode()) {
@ -134,7 +126,7 @@ void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
} else {
marker->ClearFlag(HValue::kEndsLiveRange);
}
if (!went_live_since_last_simulate_->Contains(index)) {
if (!went_live_since_last_simulate_.Contains(index)) {
marker->set_next_simulate(last_simulate_);
}
if (marker->kind() == HEnvironmentMarker::LOOKUP) {
@ -142,11 +134,11 @@ void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
} else {
ASSERT(marker->kind() == HEnvironmentMarker::BIND);
live->Remove(index);
went_live_since_last_simulate_->Add(index);
went_live_since_last_simulate_.Add(index);
}
if (collect_markers_) {
// Populate |markers_| list during the first pass.
markers_->Add(marker, zone());
markers_.Add(marker, zone());
}
break;
}
@ -173,8 +165,8 @@ void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
int return_id = enter->return_targets()->at(i)->block_id();
// When an AbnormalExit is involved, it can happen that the return
// target block doesn't actually exist.
if (return_id < live_at_block_start_->length()) {
live->Union(*live_at_block_start_->at(return_id));
if (return_id < live_at_block_start_.length()) {
live->Union(*live_at_block_start_[return_id]);
}
}
last_simulate_ = NULL;
@ -191,7 +183,7 @@ void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
}
case HValue::kSimulate:
last_simulate_ = HSimulate::cast(instr);
went_live_since_last_simulate_->Clear();
went_live_since_last_simulate_.Clear();
break;
default:
break;
@ -199,47 +191,46 @@ void EnvironmentSlotLivenessAnalyzer::UpdateLivenessAtInstruction(
}
void EnvironmentSlotLivenessAnalyzer::AnalyzeAndTrim() {
HPhase phase("H_EnvironmentLivenessAnalysis", graph_);
if (maximum_environment_size_ == 0) return;
void HEnvironmentLivenessAnalysisPhase::Run() {
ASSERT(maximum_environment_size_ > 0);
// Main iteration. Compute liveness of environment slots, and store it
// for each block until it doesn't change any more. For efficiency, visit
// blocks in reverse order and walk backwards through each block. We
// need several iterations to propagate liveness through nested loops.
BitVector* live = new(zone()) BitVector(maximum_environment_size_, zone());
BitVector* worklist = new(zone()) BitVector(block_count_, zone());
BitVector live(maximum_environment_size_, zone());
BitVector worklist(block_count_, zone());
for (int i = 0; i < block_count_; ++i) {
worklist->Add(i);
worklist.Add(i);
}
while (!worklist->IsEmpty()) {
while (!worklist.IsEmpty()) {
for (int block_id = block_count_ - 1; block_id >= 0; --block_id) {
if (!worklist->Contains(block_id)) {
if (!worklist.Contains(block_id)) {
continue;
}
worklist->Remove(block_id);
worklist.Remove(block_id);
last_simulate_ = NULL;
HBasicBlock* block = graph_->blocks()->at(block_id);
UpdateLivenessAtBlockEnd(block, live);
HBasicBlock* block = graph()->blocks()->at(block_id);
UpdateLivenessAtBlockEnd(block, &live);
for (HInstruction* instr = block->last(); instr != NULL;
instr = instr->previous()) {
UpdateLivenessAtInstruction(instr, live);
UpdateLivenessAtInstruction(instr, &live);
}
// Reached the start of the block, do necessary bookkeeping:
// store computed information for this block and add predecessors
// to the work list as necessary.
first_simulate_->Set(block_id, last_simulate_);
first_simulate_invalid_for_index_->at(block_id)->CopyFrom(
*went_live_since_last_simulate_);
if (live_at_block_start_->at(block_id)->UnionIsChanged(*live)) {
first_simulate_.Set(block_id, last_simulate_);
first_simulate_invalid_for_index_[block_id]->CopyFrom(
went_live_since_last_simulate_);
if (live_at_block_start_[block_id]->UnionIsChanged(live)) {
for (int i = 0; i < block->predecessors()->length(); ++i) {
worklist->Add(block->predecessors()->at(i)->block_id());
worklist.Add(block->predecessors()->at(i)->block_id());
}
if (block->IsInlineReturnTarget()) {
worklist->Add(block->inlined_entry_block()->block_id());
worklist.Add(block->inlined_entry_block()->block_id());
}
}
}
@ -248,18 +239,18 @@ void EnvironmentSlotLivenessAnalyzer::AnalyzeAndTrim() {
}
// Analysis finished. Zap dead environment slots.
for (int i = 0; i < markers_->length(); ++i) {
ZapEnvironmentSlotsForInstruction(markers_->at(i));
for (int i = 0; i < markers_.length(); ++i) {
ZapEnvironmentSlotsForInstruction(markers_[i]);
}
for (int block_id = block_count_ - 1; block_id >= 0; --block_id) {
HBasicBlock* block = graph_->blocks()->at(block_id);
UpdateLivenessAtBlockEnd(block, live);
ZapEnvironmentSlotsInSuccessors(block, live);
HBasicBlock* block = graph()->blocks()->at(block_id);
UpdateLivenessAtBlockEnd(block, &live);
ZapEnvironmentSlotsInSuccessors(block, &live);
}
// Finally, remove the HEnvironment{Bind,Lookup} markers.
for (int i = 0; i < markers_->length(); ++i) {
markers_->at(i)->DeleteAndReplaceWith(NULL);
for (int i = 0; i < markers_.length(); ++i) {
markers_[i]->DeleteAndReplaceWith(NULL);
}
}

25
src/hydrogen-environment-liveness.h
View File

@ -43,11 +43,11 @@ namespace internal {
// the last lookup that refers to them.
// Slots are identified by their index and only affected if whitelisted in
// HOptimizedGraphBuilder::IsEligibleForEnvironmentLivenessAnalysis().
class EnvironmentSlotLivenessAnalyzer {
class HEnvironmentLivenessAnalysisPhase : public HPhase {
public:
explicit EnvironmentSlotLivenessAnalyzer(HGraph* graph);
explicit HEnvironmentLivenessAnalysisPhase(HGraph* graph);
void AnalyzeAndTrim();
void Run();
private:
void ZapEnvironmentSlot(int index, HSimulate* simulate);
@ -56,13 +56,6 @@ class EnvironmentSlotLivenessAnalyzer {
void UpdateLivenessAtBlockEnd(HBasicBlock* block, BitVector* live);
void UpdateLivenessAtInstruction(HInstruction* instr, BitVector* live);
Zone* zone() { return &zone_; }
HGraph* graph_;
// Use a dedicated Zone for this phase, with a ZoneScope to ensure it
// gets freed.
Zone zone_;
int block_count_;
// Largest number of local variables in any environment in the graph
@ -70,21 +63,23 @@ class EnvironmentSlotLivenessAnalyzer {
int maximum_environment_size_;
// Per-block data. All these lists are indexed by block_id.
ZoneList<BitVector*>* live_at_block_start_;
ZoneList<HSimulate*>* first_simulate_;
ZoneList<BitVector*>* first_simulate_invalid_for_index_;
ZoneList<BitVector*> live_at_block_start_;
ZoneList<HSimulate*> first_simulate_;
ZoneList<BitVector*> first_simulate_invalid_for_index_;
// List of all HEnvironmentMarker instructions for quick iteration/deletion.
// It is populated during the first pass over the graph, controlled by
// |collect_markers_|.
ZoneList<HEnvironmentMarker*>* markers_;
ZoneList<HEnvironmentMarker*> markers_;
bool collect_markers_;
// Keeps track of the last simulate seen, as well as the environment slots
// for which a new live range has started since (so they must not be zapped
// in that simulate when the end of another live range of theirs is found).
HSimulate* last_simulate_;
BitVector* went_live_since_last_simulate_;
BitVector went_live_since_last_simulate_;
DISALLOW_COPY_AND_ASSIGN(HEnvironmentLivenessAnalysisPhase);
};

5
src/hydrogen.cc
View File

@ -3962,9 +3962,8 @@ bool HGraph::Optimize(SmartArrayPointer<char>* bailout_reason) {
Verify(true);
#endif
if (FLAG_analyze_environment_liveness) {
EnvironmentSlotLivenessAnalyzer esla(this);
esla.AnalyzeAndTrim();
if (FLAG_analyze_environment_liveness && maximum_environment_size() != 0) {
Run<HEnvironmentLivenessAnalysisPhase>();
}
PropagateDeoptimizingMark();