Generate inline code for contextual loads.

Generate inline code for contextual loads.

Contextual load requires only a map check followed by a cell hole
check so we can generate pretty compact code for that. The fact that
we have inlined code is marked by mov ecx, offset instruction after
the IC call. Inlining is only enabled inside loops and in non-builtin
functions.

The generated code size increase is about 3%. This descreased the
pc-to-code cache hit rate in some of the benchmarks that trigger
GC. To compensate we now have 4 times as much entries in the cache.

Committed: http://code.google.com/p/v8/source/detail?r=5497

[Søren Thygesen Gjesse, 2010-09-20 06:50:08]

LGTM

http://codereview.chromium.org/3402014/diff/1/5
File src/ia32/codegen-ia32.cc (right):

http://codereview.chromium.org/3402014/diff/1/5#newcode9431
src/ia32/codegen-ia32.cc:9431: masm()->mov(result.reg(), Factory::null_value());
How about having a --debug-code guarded assert here that result.reg() is never
null when this code is actually run.

[Vitaly Repeshko, 2010-09-20 13:51:27]

On 2010/09/20 06:50:08, Søren Gjesse wrote:
> LGTM

Thanks!
 
> http://codereview.chromium.org/3402014/diff/1/5
> File src/ia32/codegen-ia32.cc (right):
> 
> http://codereview.chromium.org/3402014/diff/1/5#newcode9431
> src/ia32/codegen-ia32.cc:9431: masm()->mov(result.reg(),
Factory::null_value());
> How about having a --debug-code guarded assert here that result.reg() is never
> null when this code is actually run.

Good idea. I added a check that this is actually a global cell.


-- Vitaly