Reviewers: Jakob, titzer,
Message:
Ben: PTAL.
Jakob: FYI, comments are always welcome.
Description:
First simplistic implementation of escape analysis.
[email protected],[email protected]
Please review this at https://codereview.chromium.org/17914002/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/flag-definitions.h
M src/hydrogen-instructions.h
M src/hydrogen.cc
Index: src/flag-definitions.h
diff --git a/src/flag-definitions.h b/src/flag-definitions.h
index
91186defe4737774362661fba2f130888d3311ad..b07354a5e59f8d2061354e5c54aa2292d5ad7aec
100644
--- a/src/flag-definitions.h
+++ b/src/flag-definitions.h
@@ -214,6 +214,7 @@ DEFINE_bool(use_range, true, "use hydrogen range
analysis")
DEFINE_bool(use_gvn, true, "use hydrogen global value numbering")
DEFINE_bool(use_canonicalizing, true, "use hydrogen instruction
canonicalizing")
DEFINE_bool(use_inlining, true, "use function inlining")
+DEFINE_bool(use_escape_analysis, false, "use hydrogen escape analysis")
DEFINE_int(max_inlined_source_size, 600,
"maximum source size in bytes considered for a single inlining")
DEFINE_int(max_inlined_nodes, 196,
@@ -234,6 +235,7 @@ DEFINE_bool(trace_all_uses, false, "trace all use
positions")
DEFINE_bool(trace_range, false, "trace range analysis")
DEFINE_bool(trace_gvn, false, "trace global value numbering")
DEFINE_bool(trace_representation, false, "trace representation types")
+DEFINE_bool(trace_escape_analysis, false, "trace hydrogen escape analysis")
DEFINE_bool(trace_track_allocation_sites, false,
"trace the tracking of allocation sites")
DEFINE_bool(trace_migration, false, "trace object migration")
Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index
6de90deb5b3309ff9069abff3f85af5951deaf8f..cdb24e42401342094c0706d29f5555d7a31b940c
100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1058,6 +1058,9 @@ class HValue: public ZoneObject {
void RemoveLastAddedRange();
void ComputeInitialRange(Zone* zone);
+ // Escape analysis helpers.
+ virtual bool HasEscapingOperandAt(int index) { return true; }
+
// Representation helpers.
virtual Representation observed_input_representation(int index) {
return Representation::None();
@@ -1429,6 +1432,7 @@ class HDummyUse: public HTemplateInstruction<1> {
HValue* value() { return OperandAt(0); }
+ virtual bool HasEscapingOperandAt(int index) { return false; }
virtual Representation RequiredInputRepresentation(int index) {
return Representation::None();
}
@@ -1888,6 +1892,7 @@ class HSimulate: public HInstruction {
virtual int OperandCount() { return values_.length(); }
virtual HValue* OperandAt(int index) const { return values_[index]; }
+ virtual bool HasEscapingOperandAt(int index) { return false; }
virtual Representation RequiredInputRepresentation(int index) {
return Representation::None();
}
@@ -2797,6 +2802,7 @@ class HCheckMaps: public HTemplateInstruction<2> {
return check_map;
}
+ virtual bool HasEscapingOperandAt(int index) { return false; }
virtual Representation RequiredInputRepresentation(int index) {
return Representation::Tagged();
}
@@ -3228,6 +3234,7 @@ class HArgumentsObject: public
HTemplateInstruction<0> {
virtual int OperandCount() { return values_.length(); }
virtual HValue* OperandAt(int index) const { return values_[index]; }
+ virtual bool HasEscapingOperandAt(int index) { return false; }
virtual Representation RequiredInputRepresentation(int index) {
return Representation::None();
}
@@ -5431,6 +5438,7 @@ class HLoadNamedField: public HTemplateInstruction<2>
{
HObjectAccess access() const { return access_; }
Representation field_representation() const { return representation_; }
+ virtual bool HasEscapingOperandAt(int index) { return false; }
virtual Representation RequiredInputRepresentation(int index) {
return Representation::Tagged();
}
@@ -5763,6 +5771,7 @@ class HStoreNamedField: public
HTemplateInstruction<2> {
DECLARE_CONCRETE_INSTRUCTION(StoreNamedField)
+ virtual bool HasEscapingOperandAt(int index) { return index == 1; }
virtual Representation RequiredInputRepresentation(int index) {
if (FLAG_track_double_fields &&
index == 1 && field_representation_.IsDouble()) {
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
b03bf699389be7864587415c6143280159f27979..94ff56d373ffe73b4fbecf862ce6e1c04f64e4b4
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -2613,6 +2613,62 @@ void HGraph::InferTypes(ZoneList<HValue*>* worklist)
{
}
+class HEscapeAnalysis BASE_EMBEDDED {
+ public:
+ explicit HEscapeAnalysis(HGraph* graph)
+ : graph_(graph), zone_(graph->zone()), captured_(0, zone_) { }
+
+ void Analyze();
+
+ private:
+ void CollectCapturedValues();
+ void CollectIfNoEscapingUses(HInstruction* instr);
+
+ HGraph* graph_;
+ Zone* zone_;
+ ZoneList<HValue*> captured_;
+};
+
+
+void HEscapeAnalysis::CollectIfNoEscapingUses(HInstruction* instr) {
+ for (HUseIterator it(instr->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", instr->id(),
+ instr->Mnemonic(), use->id(), use->Mnemonic(), it.index());
+ }
+ return;
+ }
+ }
+ if (FLAG_trace_escape_analysis) {
+ PrintF("#%d (%s) is being captured\n", instr->id(), instr->Mnemonic());
+ }
+ captured_.Add(instr, zone_);
+}
+
+
+void HEscapeAnalysis::CollectCapturedValues() {
+ int block_count = graph_->blocks()->length();
+ for (int i = 0; i < block_count; ++i) {
+ HBasicBlock* block = graph_->blocks()->at(i);
+ HInstruction* instr = block->first();
+ while (instr != block->end()) {
+ if (instr->IsAllocate() || instr->IsAllocateObject()) {
+ CollectIfNoEscapingUses(instr);
+ }
+ instr = instr->next();
+ }
+ }
+}
+
+
+void HEscapeAnalysis::Analyze() {
+ HPhase phase("H_Escape analysis", graph_);
+ CollectCapturedValues();
+}
+
+
class HRangeAnalysis BASE_EMBEDDED {
public:
explicit HRangeAnalysis(HGraph* graph) :
@@ -3983,6 +4039,7 @@ bool HGraph::Optimize(SmartArrayPointer<char>*
bailout_reason) {
}
PropagateDeoptimizingMark();
+
if (!CheckConstPhiUses()) {
*bailout_reason = SmartArrayPointer<char>(StrDup(
"Unsupported phi use of const variable"));
@@ -4029,6 +4086,11 @@ bool HGraph::Optimize(SmartArrayPointer<char>*
bailout_reason) {
if (FLAG_use_canonicalizing) Canonicalize();
+ if (FLAG_use_escape_analysis) {
+ HEscapeAnalysis escapeAnalysis(this);
+ escapeAnalysis.Analyze();
+ }
+
if (FLAG_use_gvn) GlobalValueNumbering();
if (FLAG_use_range) {
--
--
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