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Fix for bug 351257: type feedback vector initialization issue.

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The feedback vector is stored in the shared function info, and there
is an effort to reuse it when re-running full code generation as a
prelude to creating optimized code. However we shouldn't reuse the
vector for lazily compiled methods on first compile, as scoping analysis
can change the allocation of vector slots.

BUG=351257
LOG=N
R=danno@chromium.org, bmeuer@chromium.org

Review URL: https://codereview.chromium.org/196723003

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19854 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
mvstanton@chromium.org 2014-03-12 15:18:17 +00:00
parent 8bcd43b8cf
commit 021d9e778c
2 changed files with 42 additions and 7 deletions
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12
src/compiler.cc
View File

@ -141,13 +141,11 @@ void CompilationInfo::Initialize(Isolate* isolate,
}
set_bailout_reason(kUnknown);
if (!shared_info().is_null()) {
FixedArray* info_feedback_vector = shared_info()->feedback_vector();
if (info_feedback_vector->length() > 0) {
// We should initialize the CompilationInfo feedback vector from the
// passed in shared info, rather than creating a new one.
feedback_vector_ = Handle<FixedArray>(info_feedback_vector, isolate);
}
if (!shared_info().is_null() && shared_info()->is_compiled()) {
// We should initialize the CompilationInfo feedback vector from the
// passed in shared info, rather than creating a new one.
feedback_vector_ = Handle<FixedArray>(shared_info()->feedback_vector(),
isolate);
}
}

37
test/cctest/test-compiler.cc
View File

@ -347,6 +347,43 @@ TEST(FeedbackVectorPreservedAcrossRecompiles) {
}
TEST(FeedbackVectorRecreatedOnScopeChanges) {
if (i::FLAG_always_opt || !i::FLAG_lazy) return;
CcTest::InitializeVM();
v8::HandleScope scope(CcTest::isolate());
CompileRun("function builder() {"
" call_target = function() { return 3; };"
" return (function() {"
" eval('');"
" return function() {"
" 'use strict';"
" call_target();"
" }"
" })();"
"}"
"morphing_call = builder();");
Handle<JSFunction> f =
v8::Utils::OpenHandle(
*v8::Handle<v8::Function>::Cast(
CcTest::global()->Get(v8_str("morphing_call"))));
// morphing_call should have one feedback vector slot for the call to
// call_target(), scoping analysis having been performed.
CHECK_EQ(1, f->shared()->feedback_vector()->length());
// And yet it's not compiled.
CHECK(!f->shared()->is_compiled());
CompileRun("morphing_call();");
// On scoping analysis after lazy compile, the call is now a global
// call which needs no feedback vector slot.
CHECK_EQ(0, f->shared()->feedback_vector()->length());
CHECK(f->shared()->is_compiled());
}
// Test that optimized code for different closures is actually shared
// immediately by the FastNewClosureStub when run in the same context.
TEST(OptimizedCodeSharing) {