Have the flow graph builder collect definitions.

Have the flow graph builder collect definitions.

Before computing reaching definitions, the set of all definitions in a
function must be collected and they must be numbered.  Have the flow
graph builder collect definitions for stack-allocated variables into a
list, and implicitly number them with their list index.

Committed: http://code.google.com/p/v8/source/detail?r=4064

[Kevin Millikin (Chromium), 2010-03-08 14:50:30]

Simple code review for you.

[fschneider, 2010-03-09 09:23:05]

LGTM.

http://codereview.chromium.org/668257/diff/1/2
File src/data-flow.cc (right):

http://codereview.chromium.org/668257/diff/1/2#newcode437
src/data-flow.cc:437: if (slot != NULL &&
I'm also checking for stack locals and parameters in many locations in the
assigned variables analysis. This would be a candidate for a helper function.

http://codereview.chromium.org/668257/diff/1/2#newcode501
src/data-flow.cc:501: Variable* var =
expr->expression()->AsVariableProxy()->AsVariable();
Sometimes we use 

...->AsVariableProxy()->var()

and sometimes

...->AsVariableProxy()->AsVariable()

This is not part of this change, but could we get rid of one of them?