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[interpreter] Implement static loop depth tracking.

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This adds tracking of the loop depth to the {BytecodeGenerator} in order
to statically determine the loop nesting level for {OsrPoll} bytecodes.

R=rmcilroy@chromium.org
BUG=v8:4764

Review-Url: https://codereview.chromium.org/2176183002
Cr-Commit-Position: refs/heads/master@{#38064}
This commit is contained in:
mstarzinger 2016-07-26 08:41:56 -07:00 committed by Commit bot
parent fbf04c3705
commit 7bb24abe03
2 changed files with 9 additions and 4 deletions
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12
src/interpreter/bytecode-generator.cc
View File

@ -266,7 +266,10 @@ class BytecodeGenerator::ControlScopeForIteration final
LoopBuilder* loop_builder)
: ControlScope(generator),
statement_(statement),
loop_builder_(loop_builder) {}
loop_builder_(loop_builder) {
generator->loop_depth_++;
}
~ControlScopeForIteration() { generator()->loop_depth_--; }
protected:
bool Execute(Command command, Statement* statement) override {
@ -597,7 +600,8 @@ BytecodeGenerator::BytecodeGenerator(CompilationInfo* info)
execution_result_(nullptr),
register_allocator_(nullptr),
generator_resume_points_(info->literal()->yield_count(), info->zone()),
generator_state_() {
generator_state_(),
loop_depth_(0) {
InitializeAstVisitor(isolate()->stack_guard()->real_climit());
}
@ -719,8 +723,8 @@ void BytecodeGenerator::VisitIterationHeader(IterationStatement* stmt,
if (FLAG_ignition_osr) {
// TODO(4764): Merge this with another bytecode (e.g. {Jump} back edge).
// TODO(4764): Investigate interaction with generators.
// TODO(4764): Track and pass correct loop depth.
builder()->OsrPoll(0);
int level = Min(loop_depth_, AbstractCode::kMaxLoopNestingMarker - 1);
builder()->OsrPoll(level);
}
if (stmt->yield_count() > 0) {

1
src/interpreter/bytecode-generator.h
View File

@ -214,6 +214,7 @@ class BytecodeGenerator final : public AstVisitor<BytecodeGenerator> {
RegisterAllocationScope* register_allocator_;
ZoneVector<BytecodeLabel> generator_resume_points_;
Register generator_state_;
int loop_depth_;
};
} // namespace interpreter