A type vector with multiple IC types needs metadata.

A type vector with multiple IC types needs metadata.

This CL adds a bitset to describe the type of IC in each IC slot.
This is necessary for clearing ICs of different types.

With FLAG_vector_ics off (the current state), it's not required because
CALL_IC is the only type of IC in the vector.

R=ishell@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=24911

[mvstanton, 2014-10-27 11:55:45]

Hi Igor,
Here is one of the changes for vector ics. This infrastructure is only utilized
when the vector_ics flag is on, with some careful guard/default values when it's
off. PTAL, thx!
--Michael

[Igor Sheludko, 2014-10-27 15:23:24]

lgtm with nits:

https://codereview.chromium.org/679073002/diff/1/src/type-feedback-vector.cc
File src/type-feedback-vector.cc (right):

https://codereview.chromium.org/679073002/diff/1/src/type-feedback-vector.cc#...
src/type-feedback-vector.cc:17: if (kind == Code::CALL_IC) {
What about using switch?

https://codereview.chromium.org/679073002/diff/1/src/type-feedback-vector.cc#...
src/type-feedback-vector.cc:33: if (kind == KindCallIC)
Same here.

https://codereview.chromium.org/679073002/diff/1/src/utils.h
File src/utils.h (right):

https://codereview.chromium.org/679073002/diff/1/src/utils.h#newcode272
src/utils.h:272: int set_bits = (static_cast<int>(value) << shift(item));
Maybe it would be better to call shift() only once.

[mvstanton, 2014-10-27 16:34:42]

Committed patchset #2 (id:20001) manually as 24911 (presubmit successful).