[Mesa-dev] [PATCH 1/2] glsl: add a mechanism to allow #extension directives in the middle of shaders

[Kenneth Graunke]

On Tuesday, July 08, 2014 08:29:44 PM Marek Olšák wrote:
> From: Marek Olšák <marek.olsak at amd.com>
> 
> This is needed to make Unigine Heaven 4.0 and Unigine Valley 1.0 work
> with sample shading.
> 
> Also, if this is disabled, the error message at least makes sense now.
> ---
>  src/glsl/glsl_parser.yy         | 8 ++++++++
>  src/glsl/glsl_parser_extras.cpp | 2 ++
>  src/glsl/glsl_parser_extras.h   | 2 ++
>  src/mesa/main/mtypes.h          | 5 +++++
>  4 files changed, 17 insertions(+)
> 
> diff --git a/src/glsl/glsl_parser.yy b/src/glsl/glsl_parser.yy
> index b989749..4c87163 100644
> --- a/src/glsl/glsl_parser.yy
> +++ b/src/glsl/glsl_parser.yy
> @@ -376,6 +376,14 @@ external_declaration_list:
>        if ($2 != NULL)
>           state->translation_unit.push_tail(& $2->link);
>     }
> +   | external_declaration_list extension_statement {
> +      if (!state->allow_extension_directive_midshader) {
> +         _mesa_glsl_error(& @2, state,
> +                          "#extension directive is not allowed "
> +                          "in the middle of a shader");
> +         YYERROR;
> +      }
> +   }
>     ;
>  
>  variable_identifier:
> diff --git a/src/glsl/glsl_parser_extras.cpp 
b/src/glsl/glsl_parser_extras.cpp
> index b327c2b..890123a 100644
> --- a/src/glsl/glsl_parser_extras.cpp
> +++ b/src/glsl/glsl_parser_extras.cpp
> @@ -210,6 +210,8 @@ _mesa_glsl_parse_state::_mesa_glsl_parse_state(struct 
gl_context *_ctx,
>     this->early_fragment_tests = false;
>     memset(this->atomic_counter_offsets, 0,
>            sizeof(this->atomic_counter_offsets));
> +   this->allow_extension_directive_midshader =
> +      ctx->Const.AllowGLSLExtensionDirectiveMidShader;
>  }
>  
>  /**
> diff --git a/src/glsl/glsl_parser_extras.h b/src/glsl/glsl_parser_extras.h
> index 1791816..f720d6a 100644
> --- a/src/glsl/glsl_parser_extras.h
> +++ b/src/glsl/glsl_parser_extras.h
> @@ -490,6 +490,8 @@ struct _mesa_glsl_parse_state {
>  
>     /** Atomic counter offsets by binding */
>     unsigned atomic_counter_offsets[MAX_COMBINED_ATOMIC_BUFFERS];
> +
> +   bool allow_extension_directive_midshader;
>  };
>  
>  # define YYLLOC_DEFAULT(Current, Rhs, N)			\
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index a7126fd..b42a175 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -3349,6 +3349,11 @@ struct gl_constants
>     GLuint ForceGLSLVersion;
>  
>     /**
> +    * Allow GLSL #extension directives in the middle of shaders.
> +    */
> +   GLboolean AllowGLSLExtensionDirectiveMidShader;
> +
> +   /**
>      * Does the driver support real 32-bit integers?  (Otherwise, integers 
are
>      * simulated via floats.)
>      */
> 

Looks great to me, Marek - thanks for doing this.

I'd written a similar patch, but introduced shift/reduce conflicts while doing 
it.  Looks like you avoided that - nice :)

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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