Use a global ref-counted singleton for long name map.

Use a global ref-counted singleton for long name map.

This makes sure the same varying/uniform variables maps to the unique name in vertex/fragment shader.

BUG=
TEST=webgl conformance tests
Committed: https://code.google.com/p/angleproject/source/detail?r=950

[Zhenyao Mo, 2012-01-19 23:36:46]

Tested with WebGL conformance tests.  Please review.

[Zhenyao Mo, 2012-01-19 23:37:14]

Please review.

[kbr1, 2012-01-19 23:50:42]

https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
File src/compiler/MapLongVariableNames.h (right):

https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
src/compiler/MapLongVariableNames.h:58: MapLongVariableNames();
Could you pass the LongNameMap* to the constructor and have the Compiler pass it
in? That will avoid the need for the ScopedLongNameMap class.

[Zhenyao Mo, 2012-01-19 23:56:36]

https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
File src/compiler/MapLongVariableNames.h (right):

https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
src/compiler/MapLongVariableNames.h:58: MapLongVariableNames();
On 2012/01/19 23:50:43, kbr1 wrote:
> Could you pass the LongNameMap* to the constructor and have the Compiler pass
it
> in? That will avoid the need for the ScopedLongNameMap class.

The ScopedLongNameMap is also held in Compiler to keep the global map alive.  If
we remove ScopedLongNameMap, then we need to call GetInstance in Compiler
constructor and Release in destructor.  I feel have a Scoped* class makes it
less error-prone.  I can go the other way though.  Let me know.

[kbr1, 2012-01-19 23:59:59]

On 2012/01/19 23:56:36, Zhenyao Mo wrote:
>
https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
> File src/compiler/MapLongVariableNames.h (right):
> 
>
https://codereview.appspot.com/5556065/diff/3002/src/compiler/MapLongVariable...
> src/compiler/MapLongVariableNames.h:58: MapLongVariableNames();
> On 2012/01/19 23:50:43, kbr1 wrote:
> > Could you pass the LongNameMap* to the constructor and have the Compiler
pass
> it
> > in? That will avoid the need for the ScopedLongNameMap class.
> 
> The ScopedLongNameMap is also held in Compiler to keep the global map alive. 
If
> we remove ScopedLongNameMap, then we need to call GetInstance in Compiler
> constructor and Release in destructor.  I feel have a Scoped* class makes it
> less error-prone.  I can go the other way though.  Let me know.

I noticed the use in ShHandle.h, but on the whole I think it would be better to
just have the Compiler call GetInstance() and Release(), and pass the instance
down. The use of the ScopedLongNameMap inside
MapLongVariableNames::mapGlobalLongName() is too subtle.

[Zhenyao Mo, 2012-01-20 00:30:35]

Revised and tested with WebGL conformance tests.  Please review again.

[kbr1, 2012-01-20 00:34:47]

Thanks, looks great. LGTM