Add flag to tracing element kind transitions

Add flag to trace element kind transitions

Currently only traces transitions from generated ia32 code.

BUG=none
TEST=none

Committed: http://code.google.com/p/v8/source/detail?r=9715

[danno, 2011-10-19 15:31:15]

PTAL.

[Jakob Kummerow, 2011-10-19 16:02:28]

LGTM with nits.

http://codereview.chromium.org/8357004/diff/4001/src/flag-definitions.h
File src/flag-definitions.h (right):

http://codereview.chromium.org/8357004/diff/4001/src/flag-definitions.h#newco...
src/flag-definitions.h:531: DEFINE_bool(trace_element_transitions, false, "print
element transitions")
For consistency, I'd prefer to have the plural form "elements" everywhere.

http://codereview.chromium.org/8357004/diff/4001/src/frames.cc
File src/frames.cc (right):

http://codereview.chromium.org/8357004/diff/4001/src/frames.cc#newcode731
src/frames.cc:731: PrintF(" ");
Insert this printed space into the PrintF() below.

http://codereview.chromium.org/8357004/diff/4001/src/objects.cc
File src/objects.cc (right):

http://codereview.chromium.org/8357004/diff/4001/src/objects.cc#newcode1126
src/objects.cc:1126: PrintF("elements transition [");
It doesn't make a difference for the current usage of this method, but since it
does take a FILE* parameter for the output file, it would make sense to print
*all* output to |file| using PrintF(FILE* out, const char* format, ...).

http://codereview.chromium.org/8357004/diff/4001/src/objects.cc#newcode8110
src/objects.cc:8110: ElementsKind elements_kind(GetElementsKind());
nit: for consistency with line 8156:
ElementsKind elements_kind = GetElementsKind();

[danno, 2011-10-20 08:51:16]

http://codereview.chromium.org/8357004/diff/4001/src/flag-definitions.h
File src/flag-definitions.h (right):

http://codereview.chromium.org/8357004/diff/4001/src/flag-definitions.h#newco...
src/flag-definitions.h:531: DEFINE_bool(trace_element_transitions, false, "print
element transitions")
On 2011/10/19 16:02:28, Jakob wrote:
> For consistency, I'd prefer to have the plural form "elements" everywhere.

Done.

http://codereview.chromium.org/8357004/diff/4001/src/objects.cc
File src/objects.cc (right):

http://codereview.chromium.org/8357004/diff/4001/src/objects.cc#newcode1126
src/objects.cc:1126: PrintF("elements transition [");
On 2011/10/19 16:02:28, Jakob wrote:
> It doesn't make a difference for the current usage of this method, but since
it
> does take a FILE* parameter for the output file, it would make sense to print
> *all* output to |file| using PrintF(FILE* out, const char* format, ...).

Done.

[Jakob Kummerow, 2011-10-20 09:23:47]

LGTM

[Yang, 2011-10-20 09:26:25]

On 2011/10/20 09:23:47, Jakob wrote:
> LGTM

Rubberstamped LGTM.