Check that the incoming type to a default precision qualifier statement is valid.

Check that the incoming type to a default precision qualifier statement is valid.

Fixes new WebGL conformance tests
shader-with-illegal-default-precision.frag.html and
shader-with-illegal-default-precision.vert.html per
http://www.khronos.org/bugzilla/show_bug.cgi?id=781 . Also ran WebGL
1.0.1 conformance tests; no regressions.

BUG=https://code.google.com/p/angleproject/issues/detail?id=410
Committed: https://code.google.com/p/angleproject/source/detail?r=1824

[kbr1, 2013-02-05 01:43:21]

Nicolas, Alok, could you please review this?

Nicolas, any chance you could help run this change against the OpenGL ES 2.0
conformance suite to check for any regressions? Thanks in advance.

[kbr1, 2013-02-05 02:05:56]

https://codereview.appspot.com/7302043/diff/2001/src/compiler/glslang.y
File src/compiler/glslang.y (right):

https://codereview.appspot.com/7302043/diff/2001/src/compiler/glslang.y#newco...
src/compiler/glslang.y:995: context->error($1.line, "illegal type argument for
default precision qualifier", getBasicString($3.type));
Note I couldn't find how to turn a TPublicType back into the original string
defining the type. Any suggestions appreciated for how to improve the error
message here.

[Alok Priyadarshi, 2013-02-05 05:44:34]

lgtm

https://codereview.appspot.com/7302043/diff/2001/src/compiler/glslang.y
File src/compiler/glslang.y (right):

https://codereview.appspot.com/7302043/diff/2001/src/compiler/glslang.y#newco...
src/compiler/glslang.y:995: context->error($1.line, "illegal type argument for
default precision qualifier", getBasicString($3.type));
You could check if one of the TType::getFooString member functions work for you.
It is easy to construct a TType from a TPublicType.

[nicolas, 2013-02-05 15:29:10]

Looks good to me.

No Khronos ES2 regressions found.

Indeed there doesn't appear to be any TPublicType to string conversion. You
could simply add a member function to it in Types.h. Other places also appear to
be using getBasicString while they could be more informative. So I suggest to
improve all that in a separate patch set.

Thanks!

[kbr1, 2013-02-06 01:51:37]

Thanks Alok and Nicolas. Will look into improving error messages later.

[kbr1, 2013-02-06 21:12:18]

I forgot to link to the bug in the commit message. Updated above.