Initialize reaching definitions state for all flow graph nodes.

Initialize reaching definitions state for all flow graph nodes.

Reaching definitions in (RD_in) is initially empty for all nodes.  Gen
and kill sets are computed.  AST node numbers are used for nodes to
refer to their definition number.

Also: two small changes to flow graph printing.  Children of branch
nodes are visited in right-to-left order when performing depth first
search.  Instructions are numbered locally within blocks so as to not
destroy AST node number before printing (it's useful to print the
definition).

Committed: http://code.google.com/p/v8/source/detail?r=4107

[fschneider, 2010-03-11 15:58:15]

LGTM.

http://codereview.chromium.org/876001/diff/1/4
File src/data-flow.cc (right):

http://codereview.chromium.org/876001/diff/1/4#newcode1970
src/data-flow.cc:1970: PrintF("Def[%s] = {%d", *name, j);
I think you could just write 

PrintF("Def[%s] = {%d", *var->name()->ToCString(), j);

here.

http://codereview.chromium.org/876001/diff/1/5
File src/data-flow.h (right):

http://codereview.chromium.org/876001/diff/1/5#newcode134
src/data-flow.h:134: ReachingDefinitionsData() : definitions_(NULL) {}
I'd initialize killed_ and generated also to NULL here.

http://codereview.chromium.org/876001/diff/1/5#newcode137
src/data-flow.h:137: BitVector* killed_;
It's just a naming issue, but we could shorten these to kill_ and gen_ since you
refer to them as GEN and KILL in the comments as well.

[Kevin Millikin (Chromium), 2010-03-11 16:20:46]

http://codereview.chromium.org/876001/diff/1/4
File src/data-flow.cc (right):

http://codereview.chromium.org/876001/diff/1/4#newcode1970
src/data-flow.cc:1970: PrintF("Def[%s] = {%d", *name, j);
On 2010/03/11 15:58:15, fschneider wrote:
> I think you could just write 
> 
> PrintF("Def[%s] = {%d", *var->name()->ToCString(), j);
> 
> here.

OK.

http://codereview.chromium.org/876001/diff/1/5
File src/data-flow.h (right):

http://codereview.chromium.org/876001/diff/1/5#newcode134
src/data-flow.h:134: ReachingDefinitionsData() : definitions_(NULL) {}
On 2010/03/11 15:58:15, fschneider wrote:
> I'd initialize killed_ and generated also to NULL here.

Thanks.

http://codereview.chromium.org/876001/diff/1/5#newcode137
src/data-flow.h:137: BitVector* killed_;
On 2010/03/11 15:58:15, fschneider wrote:
> It's just a naming issue, but we could shorten these to kill_ and gen_ since
you
> refer to them as GEN and KILL in the comments as well.

OK.