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Insert proper padding between lazy deoptimization points and safepoints.

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On x64 we need 13 bytes for patching the call for lazy deopt. We have to
make sure that patching does not overwrite the code at the safepoint.

BUG=v8:1847
Review URL: http://codereview.chromium.org/8775009

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10126 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
fschneider@chromium.org 2011-12-01 14:19:34 +00:00
parent 75a8165950
commit 8acd4accac
2 changed files with 12 additions and 10 deletions
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20
src/x64/lithium-codegen-x64.cc
View File

@ -49,7 +49,9 @@ class SafepointGenerator : public CallWrapper {
deopt_mode_(mode) { }
virtual ~SafepointGenerator() { }
virtual void BeforeCall(int call_size) const { }
virtual void BeforeCall(int call_size) const {
codegen_->EnsureSpaceForLazyDeopt(Deoptimizer::patch_size() - call_size);
}
virtual void AfterCall() const {
codegen_->RecordSafepoint(pointers_, deopt_mode_);
@ -241,7 +243,7 @@ bool LCodeGen::GenerateBody() {
instr->CompileToNative(this);
}
}
EnsureSpaceForLazyDeopt();
EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
return !is_aborted();
}
@ -439,6 +441,7 @@ void LCodeGen::CallCodeGeneric(Handle<Code> code,
LInstruction* instr,
SafepointMode safepoint_mode,
int argc) {
EnsureSpaceForLazyDeopt(Deoptimizer::patch_size() - masm()->CallSize(code));
ASSERT(instr != NULL);
LPointerMap* pointers = instr->pointer_map();
RecordPosition(pointers->position());
@ -4176,25 +4179,24 @@ void LCodeGen::EmitIsConstructCall(Register temp) {
}
void LCodeGen::EnsureSpaceForLazyDeopt() {
void LCodeGen::EnsureSpaceForLazyDeopt(int space_needed) {
// Ensure that we have enough space after the previous lazy-bailout
// instruction for patching the code here.
int current_pc = masm()->pc_offset();
int patch_size = Deoptimizer::patch_size();
if (current_pc < last_lazy_deopt_pc_ + patch_size) {
int padding_size = last_lazy_deopt_pc_ + patch_size - current_pc;
if (current_pc < last_lazy_deopt_pc_ + space_needed) {
int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
while (padding_size > 0) {
int nop_size = padding_size > 9 ? 9 : padding_size;
__ nop(nop_size);
padding_size -= nop_size;
}
}
last_lazy_deopt_pc_ = masm()->pc_offset();
}
void LCodeGen::DoLazyBailout(LLazyBailout* instr) {
EnsureSpaceForLazyDeopt();
EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
last_lazy_deopt_pc_ = masm()->pc_offset();
ASSERT(instr->HasEnvironment());
LEnvironment* env = instr->environment();
RegisterEnvironmentForDeoptimization(env, Safepoint::kLazyDeopt);
@ -4265,7 +4267,7 @@ void LCodeGen::DoStackCheck(LStackCheck* instr) {
new DeferredStackCheck(this, instr);
__ CompareRoot(rsp, Heap::kStackLimitRootIndex);
__ j(below, deferred_stack_check->entry());
EnsureSpaceForLazyDeopt();
EnsureSpaceForLazyDeopt(Deoptimizer::patch_size());
__ bind(instr->done_label());
deferred_stack_check->SetExit(instr->done_label());
// There is no LLazyBailout instruction for stack-checks. We have to

2
src/x64/lithium-codegen-x64.h
View File

@ -305,7 +305,7 @@ class LCodeGen BASE_EMBEDDED {
Address address;
};
void EnsureSpaceForLazyDeopt();
void EnsureSpaceForLazyDeopt(int space_needed);
LChunk* const chunk_;
MacroAssembler* const masm_;