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X64: Ensure that there is always room for a call between recoreded safepoints.

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Fixes issue 1234.

BUG=v8:1234

Review URL: http://codereview.chromium.org/6624053

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7072 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
lrn@chromium.org 2011-03-07 10:30:58 +00:00
parent 3ea38d412b
commit 56753adbb8
1 changed files with 17 additions and 1 deletions
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18
src/x64/lithium-codegen-x64.cc
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@ -48,23 +48,39 @@ class SafepointGenerator : public PostCallGenerator {
: codegen_(codegen),
pointers_(pointers),
deoptimization_index_(deoptimization_index),
ensure_reloc_space_(ensure_reloc_space) { }
ensure_reloc_space_(ensure_reloc_space),
previous_safepoint_position_(-kMinSafepointSize) { }
virtual ~SafepointGenerator() { }
virtual void Generate() {
// Ensure that we have enough space after the previous safepoint position
// for the generated code there.
int position = codegen_->masm()->pc_offset();
ASSERT(position > previous_safepoint_position_);
if (position < previous_safepoint_position_ + kMinSafepointSize) {
int padding_size =
previous_safepoint_position_ + kMinSafepointSize - position;
STATIC_ASSERT(kMinSafepointSize <= 9); // One multibyte nop is enough.
codegen_->masm()->nop(padding_size);
position += padding_size;
}
// Ensure that we have enough space in the reloc info to patch
// this with calls when doing deoptimization.
if (ensure_reloc_space_) {
codegen_->masm()->RecordComment(RelocInfo::kFillerCommentString, true);
}
codegen_->RecordSafepoint(pointers_, deoptimization_index_);
previous_safepoint_position_ = position;
}
private:
static const int kMinSafepointSize =
MacroAssembler::kShortCallInstructionLength;
LCodeGen* codegen_;
LPointerMap* pointers_;
int deoptimization_index_;
bool ensure_reloc_space_;
int previous_safepoint_position_;
};