Reviewers: Jakob,
Description:
Allow constants to be deleted by reinserting them into the graph as needed.
BUG=
Please review this at https://codereview.chromium.org/31943002/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+22, -22 lines):
M src/code-stubs-hydrogen.cc
M src/hydrogen-dce.cc
M src/hydrogen-instructions.cc
M src/hydrogen.h
M src/hydrogen.cc
Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index
a695161801999b29da4342e3f9b86a92a600c409..a273c1b19a185f8081926a6777477ff9a76420a1
100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -150,10 +150,6 @@ bool CodeStubGraphBuilderBase::BuildGraph() {
next_block->SetJoinId(BailoutId::StubEntry());
set_current_block(next_block);
- HConstant* undefined_constant =
- Add<HConstant>(isolate()->factory()->undefined_value());
- graph()->set_undefined_constant(undefined_constant);
-
for (int i = 0; i < param_count; ++i) {
HParameter* param =
Add<HParameter>(i, HParameter::REGISTER_PARAMETER);
Index: src/hydrogen-dce.cc
diff --git a/src/hydrogen-dce.cc b/src/hydrogen-dce.cc
index
3b64107fa119fe1c0245bd33313b80c1809c33d4..e101ee5bcc58bd624358005a54b96d23237d3d21
100644
--- a/src/hydrogen-dce.cc
+++ b/src/hydrogen-dce.cc
@@ -98,11 +98,7 @@ void HDeadCodeEliminationPhase::RemoveDeadInstructions()
{
HInstruction* instr = it.Current();
if (!instr->CheckFlag(HValue::kIsLive)) {
// Instruction has not been marked live, so remove it.
- if (!instr->IsConstant() || instr->block()->block_id() != 0) {
- // TODO(titzer): Some global constants in block 0 can be used
- // again later, and can't currently be removed. Fix that.
- instr->DeleteAndReplaceWith(NULL);
- }
+ instr->DeleteAndReplaceWith(NULL);
} else {
// Clear the liveness flag to leave the graph clean for the next
DCE.
instr->ClearFlag(HValue::kIsLive);
Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index
867fa50fca25aa30e5508edc5368d76b23c7a576..3a367e2e43155248501bd6718fc52d81ae9b21c8
100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -2563,6 +2563,7 @@ bool HConstant::EmitAtUses() {
ASSERT(IsLinked());
if (block()->graph()->has_osr() &&
block()->graph()->IsStandardConstant(this)) {
+ // TODO(titzer): this seems like a hack that should be fixed by custom
OSR.
return true;
}
if (UseCount() == 0) return true;
Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index
14ac329575680c20e6cbac81e6298a9f6ef914da..92e99755e7079ffc73e913b56f607fda4cc991e6
100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -634,10 +634,21 @@ HConstant*
HGraph::GetConstant(SetOncePointer<HConstant>* pointer,
// Can't pass GetInvalidContext() to HConstant::New, because that will
// recursively call GetConstant
HConstant* constant = HConstant::New(zone(), NULL, value);
- constant->InsertAfter(GetConstantUndefined());
+ constant->InsertAfter(entry_block()->first());
pointer->set(constant);
+ return constant;
}
- return pointer->get();
+ return ReinsertConstantIfNecessary(pointer->get());
+}
+
+
+HConstant* HGraph::ReinsertConstantIfNecessary(HConstant* constant) {
+ if (!constant->IsLinked()) {
+ // The constant was removed from the graph. Reinsert.
+ constant->ClearFlag(HValue::kIsDead);
+ constant->InsertAfter(entry_block()->first());
+ }
+ return constant;
}
@@ -667,13 +678,14 @@ HConstant* HGraph::GetConstant##Name()
{ \
true, \
false, \
boolean_value); \
-
constant->InsertAfter(GetConstantUndefined()); \
+
constant->InsertAfter(entry_block()->first()); \
constant_##name##_.set(constant); \
}
\
- return
constant_##name##_.get(); \
+ return
ReinsertConstantIfNecessary(constant_##name##_.get()); \
}
+DEFINE_GET_CONSTANT(Undefined, undefined, HType::Tagged(), false)
DEFINE_GET_CONSTANT(True, true, HType::Boolean(), true)
DEFINE_GET_CONSTANT(False, false, HType::Boolean(), false)
DEFINE_GET_CONSTANT(Hole, the_hole, HType::Tagged(), false)
@@ -3206,10 +3218,6 @@ void HOptimizedGraphBuilder::SetUpScope(Scope*
scope) {
HInstruction* context = Add<HContext>();
environment()->BindContext(context);
- HConstant* undefined_constant = HConstant::cast(Add<HConstant>(
- isolate()->factory()->undefined_value()));
- graph()->set_undefined_constant(undefined_constant);
-
// Create an arguments object containing the initial parameters. Set the
// initial values of parameters including "this" having parameter index
0.
ASSERT_EQ(scope->num_parameters() + 1, environment()->parameter_count());
@@ -3223,6 +3231,7 @@ void HOptimizedGraphBuilder::SetUpScope(Scope* scope)
{
AddInstruction(arguments_object);
graph()->SetArgumentsObject(arguments_object);
+ HConstant* undefined_constant = graph()->GetConstantUndefined();
// Initialize specials and locals to undefined.
for (int i = environment()->parameter_count() + 1;
i < environment()->length();
Index: src/hydrogen.h
diff --git a/src/hydrogen.h b/src/hydrogen.h
index
bd28ba1b74d55da9df2dd5c11cc615a6c4ba4f0b..5eb5c9e1c45a03431492dc84bc63e691a98fcf38
100644
--- a/src/hydrogen.h
+++ b/src/hydrogen.h
@@ -338,10 +338,7 @@ class HGraph V8_FINAL : public ZoneObject {
void CollectPhis();
- void set_undefined_constant(HConstant* constant) {
- undefined_constant_.set(constant);
- }
- HConstant* GetConstantUndefined() const { return
undefined_constant_.get(); }
+ HConstant* GetConstantUndefined();
HConstant* GetConstant0();
HConstant* GetConstant1();
HConstant* GetConstantMinus1();
@@ -456,6 +453,7 @@ class HGraph V8_FINAL : public ZoneObject {
bool IsInsideNoSideEffectsScope() { return no_side_effects_scope_count_
0; }
private:
+ HConstant* ReinsertConstantIfNecessary(HConstant* constant);
HConstant* GetConstant(SetOncePointer<HConstant>* pointer,
int32_t integer_value);
@@ -475,7 +473,7 @@ class HGraph V8_FINAL : public ZoneObject {
ZoneList<HValue*> values_;
ZoneList<HPhi*>* phi_list_;
ZoneList<HInstruction*>* uint32_instructions_;
- SetOncePointer<HConstant> undefined_constant_;
+ SetOncePointer<HConstant> constant_undefined_;
SetOncePointer<HConstant> constant_0_;
SetOncePointer<HConstant> constant_1_;
SetOncePointer<HConstant> constant_minus1_;
--
--
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