Fix constant offset check for inlined write barrier to work in cases when off...

Fix constant offset check for inlined write barrier to work in cases when offset is given from tagged object pointer.

Committed: http://code.google.com/p/v8/source/detail?r=4431

[William Hesse, 2010-04-15 14:26:33]

http://codereview.chromium.org/1646008/diff/1/3
File src/x64/macro-assembler-x64.cc (right):

http://codereview.chromium.org/1646008/diff/1/3#newcode229
src/x64/macro-assembler-x64.cc:229: // We are storing pointer to an object so
either offset or
// The offset is relative to a tagged or untagged HeapObject,
// so either offset or offset + kHeapObjectTag must be a
// multiple of kPointerSize.

http://codereview.chromium.org/1646008/diff/1/3#newcode238
src/x64/macro-assembler-x64.cc:238: // Page::kMaxHeapObjectSize - kHeapObjectTag
to catch cases when pointer in
We use optimized write barrier code if the word being written to is not in a
large object page, or is in the first "page" of a large object page.  We make
sure that an offset is inside the right limits whether it is tagged or untagged.

[William Hesse, 2010-04-15 14:35:09]

LGTM.