Revision: 9203
Author: [email protected]
Date: Thu Sep 8 12:00:24 2011
Log: We don't need to track writes of
pointers to immortal immovable objects.
Review URL: http://codereview.chromium.org/7831052
http://code.google.com/p/v8/source/detail?r=9203
Modified:
/branches/experimental/gc/src/hydrogen-instructions.h
=======================================
--- /branches/experimental/gc/src/hydrogen-instructions.h Mon Aug 29
05:23:10 2011
+++ /branches/experimental/gc/src/hydrogen-instructions.h Thu Sep 8
12:00:24 2011
@@ -2248,6 +2248,18 @@
Handle<Object> handle() const { return handle_; }
bool InOldSpace() const { return !HEAP->InNewSpace(*handle_); }
+
+ bool ImmortalImmovable() const {
+ Heap* heap = HEAP;
+ if (*handle_ == heap->undefined_value()) return true;
+ if (*handle_ == heap->null_value()) return true;
+ if (*handle_ == heap->true_value()) return true;
+ if (*handle_ == heap->false_value()) return true;
+ if (*handle_ == heap->the_hole_value()) return true;
+ if (*handle_ == heap->minus_zero_value()) return true;
+ if (*handle_ == heap->nan_value()) return true;
+ return false;
+ }
virtual Representation RequiredInputRepresentation(int index) const {
return Representation::None();
@@ -3333,7 +3345,9 @@
// TODO(gc) On bleeding edge we omit write barrier when we are
// storing old space constant. We can't allow such an optimization
// on GC branch.
- return !value->type().IsSmi();
+ return !value->type().IsBoolean()
+ && !value->type().IsSmi()
+ && !(value->IsConstant() &&
HConstant::cast(value)->ImmortalImmovable());
}
--
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