[Mesa-dev] [GLSL] defined expressions

[José Fonseca]

Hi Ian,

The current GLSL preprocessor fails to parse expressions such as

  #if 1 == 0 || defined UNDEFINED

which is used by CINEBENCH r11.

The problem is the

  parser->space_tokens = 1;

statement conditional_tokens stanza -- it causes space tokens to be
emitted halfway before reaching the DEFINED token.

The attached patch is a quick bandaid to this problem, but I suspect
that other space-related issues may subsist. 

I don't quite understand space_tokens' role here, or how it is supposed
to work. I confess I'm not very familiar with bison/flex inner-workings:
I though that the tokenizer was producing tokens quite ahead of the
parser, so the parser couldn't change the behavior of the tokenizer in
flight -- but perhaps I'm mixing up with other lexel/grammar generation
tools.

Also attached is an extended version of the defined-01.vert piglit
glslparsertest test which covers more variations.

Jose
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