Change the Hydrogen representation of uses.

Change the Hydrogen representation of uses.

Rather than representing a use as a pointer to an HValue and then searching
for the specific (ambiguous) operand, we now represent a use as a pair of an
HValue and the input operand index.  Additionally, use a linked list instead
of a growable array list since we never use random access.

This allows us to remove a bunch of similarly named and subtly different
functions from the HValue API.  The cost in extra zone allocation per use is
partially offset by reusing use list nodes when replacing a use of one value
with another.

R=danno@chromium.org,fschneider@chromium.org

Committed: http://code.google.com/p/v8/source/detail?r=7674

[danno, 2011-04-20 04:25:12]

LGTM. I like it, it really cleans up the change insertion code.

http://codereview.chromium.org/6881044/diff/1/src/hydrogen-instructions.h
File src/hydrogen-instructions.h (right):

http://codereview.chromium.org/6881044/diff/1/src/hydrogen-instructions.h#new...
src/hydrogen-instructions.h:670: HUseListNode* RemoveUse(HValue* value, int
index);
How about wrapping HValue* and int in a HUse struct/class?

[fschneider, 2011-04-20 10:36:52]

LGTM as well.