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Hydrogen LoopBuilder: add support for "while(true) {...}" loops

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R=danno@chromium.org

Review URL: https://codereview.chromium.org/368243002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22207 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
jkummerow@chromium.org 2014-07-03 16:33:42 +00:00
parent 70811b5d7b
commit 5c6d414fbc
2 changed files with 55 additions and 26 deletions
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65
src/hydrogen.cc
View File

@ -1037,34 +1037,39 @@ void HGraphBuilder::IfBuilder::End() {
}
HGraphBuilder::LoopBuilder::LoopBuilder(HGraphBuilder* builder,
HValue* context,
LoopBuilder::Direction direction)
: builder_(builder),
context_(context),
direction_(direction),
finished_(false) {
header_block_ = builder->CreateLoopHeaderBlock();
body_block_ = NULL;
exit_block_ = NULL;
exit_trampoline_block_ = NULL;
increment_amount_ = builder_->graph()->GetConstant1();
HGraphBuilder::LoopBuilder::LoopBuilder(HGraphBuilder* builder) {
Initialize(builder, NULL, kWhileTrue, NULL);
}
HGraphBuilder::LoopBuilder::LoopBuilder(HGraphBuilder* builder,
HValue* context,
HGraphBuilder::LoopBuilder::LoopBuilder(HGraphBuilder* builder, HValue* context,
LoopBuilder::Direction direction) {
Initialize(builder, context, direction, builder->graph()->GetConstant1());
}
HGraphBuilder::LoopBuilder::LoopBuilder(HGraphBuilder* builder, HValue* context,
LoopBuilder::Direction direction,
HValue* increment_amount)
: builder_(builder),
context_(context),
direction_(direction),
finished_(false) {
HValue* increment_amount) {
Initialize(builder, context, direction, increment_amount);
increment_amount_ = increment_amount;
}
void HGraphBuilder::LoopBuilder::Initialize(HGraphBuilder* builder,
HValue* context,
Direction direction,
HValue* increment_amount) {
builder_ = builder;
context_ = context;
direction_ = direction;
increment_amount_ = increment_amount;
finished_ = false;
header_block_ = builder->CreateLoopHeaderBlock();
body_block_ = NULL;
exit_block_ = NULL;
exit_trampoline_block_ = NULL;
increment_amount_ = increment_amount;
}
@ -1072,6 +1077,7 @@ HValue* HGraphBuilder::LoopBuilder::BeginBody(
HValue* initial,
HValue* terminating,
Token::Value token) {
ASSERT(direction_ != kWhileTrue);
HEnvironment* env = builder_->environment();
phi_ = header_block_->AddNewPhi(env->values()->length());
phi_->AddInput(initial);
@ -1108,13 +1114,27 @@ HValue* HGraphBuilder::LoopBuilder::BeginBody(
}
void HGraphBuilder::LoopBuilder::BeginBody(int drop_count) {
ASSERT(direction_ == kWhileTrue);
HEnvironment* env = builder_->environment();
builder_->GotoNoSimulate(header_block_);
builder_->set_current_block(header_block_);
env->Drop(drop_count);
}
void HGraphBuilder::LoopBuilder::Break() {
if (exit_trampoline_block_ == NULL) {
// Its the first time we saw a break.
if (direction_ == kWhileTrue) {
HEnvironment* env = builder_->environment()->Copy();
exit_trampoline_block_ = builder_->CreateBasicBlock(env);
} else {
HEnvironment* env = exit_block_->last_environment()->Copy();
exit_trampoline_block_ = builder_->CreateBasicBlock(env);
builder_->GotoNoSimulate(exit_block_, exit_trampoline_block_);
}
}
builder_->GotoNoSimulate(exit_trampoline_block_);
builder_->set_current_block(NULL);
@ -1134,8 +1154,11 @@ void HGraphBuilder::LoopBuilder::EndBody() {
builder_->AddInstruction(increment_);
}
// Push the new increment value on the expression stack to merge into the phi.
if (direction_ != kWhileTrue) {
// Push the new increment value on the expression stack to merge into
// the phi.
builder_->environment()->Push(increment_);
}
HBasicBlock* last_block = builder_->current_block();
builder_->GotoNoSimulate(last_block, header_block_);
header_block_->loop_information()->RegisterBackEdge(last_block);

8
src/hydrogen.h
View File

@ -1669,9 +1669,11 @@ class HGraphBuilder {
kPreIncrement,
kPostIncrement,
kPreDecrement,
kPostDecrement
kPostDecrement,
kWhileTrue
};
explicit LoopBuilder(HGraphBuilder* builder); // while (true) {...}
LoopBuilder(HGraphBuilder* builder,
HValue* context,
Direction direction);
@ -1689,11 +1691,15 @@ class HGraphBuilder {
HValue* terminating,
Token::Value token);
void BeginBody(int drop_count);
void Break();
void EndBody();
private:
void Initialize(HGraphBuilder* builder, HValue* context,
Direction direction, HValue* increment_amount);
Zone* zone() { return builder_->zone(); }
HGraphBuilder* builder_;