[Mesa-dev] [PATCH 3/9] glsl: During linking, record whether a GS uses EndPrimitive().

[Kenneth Graunke]

On 09/09/2013 08:20 AM, Paul Berry wrote:
> This information will be useful in the i965 back end, since we can
> save some compilation effort if we know from the outset that the
> shader never calls EndPrimitive().
> ---
>  src/glsl/linker.cpp       | 31 +++++++++++++++++++++++++++++++
>  src/mesa/main/mtypes.h    |  2 ++
>  src/mesa/main/shaderapi.c |  1 +
>  3 files changed, 34 insertions(+)
> 
> diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
> index 8430096..f10303e 100644
> --- a/src/glsl/linker.cpp
> +++ b/src/glsl/linker.cpp
> @@ -249,6 +249,33 @@ public:
>  };
>  
>  
> +/**
> + * Visitor that determines whether or not a shader uses ir_end_primitive.
> + */
> +class find_end_primitive_visitor : public ir_hierarchical_visitor {
> +public:
> +   find_end_primitive_visitor()
> +      : found(false)
> +   {
> +      /* empty */
> +   }
> +
> +   virtual ir_visitor_status visit(ir_end_primitive *)
> +   {
> +      found = true;
> +      return visit_stop;
> +   }
> +
> +   bool end_primitive_found()
> +   {
> +      return found;
> +   }
> +
> +private:
> +   bool found;
> +};
> +
> +
>  void
>  linker_error(gl_shader_program *prog, const char *fmt, ...)
>  {
> @@ -517,6 +544,10 @@ validate_geometry_shader_executable(struct gl_shader_program *prog,
>  
>     analyze_clip_usage("geometry", prog, shader, &prog->Geom.UsesClipDistance,
>                        &prog->Geom.ClipDistanceArraySize);
> +
> +   find_end_primitive_visitor end_primitive;
> +   end_primitive.run(shader->ir);
> +   prog->Geom.UsesEndPrimitive = end_primitive.end_primitive_found();
>  }
>  
>  
> diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> index ef16c59..18a6f66 100644
> --- a/src/mesa/main/mtypes.h
> +++ b/src/mesa/main/mtypes.h
> @@ -1931,6 +1931,7 @@ struct gl_geometry_program
>                             GL_TRIANGLES, or GL_TRIANGLES_ADJACENCY_ARB */
>     GLenum OutputType; /**< GL_POINTS, GL_LINE_STRIP or GL_TRIANGLE_STRIP */
>     GLboolean UsesClipDistance;
> +   GLboolean UsesEndPrimitive;
>  };
>  
>  
> @@ -2364,6 +2365,7 @@ struct gl_shader_program
>        GLboolean UsesClipDistance;
>        GLuint ClipDistanceArraySize; /**< Size of the gl_ClipDistance array, or
>                                           0 if not present. */
> +      GLboolean UsesEndPrimitive;
>     } Geom;
>  
>     /** Vertex shader state */
> diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
> index 4fe9d9c..a2386fb 100644
> --- a/src/mesa/main/shaderapi.c
> +++ b/src/mesa/main/shaderapi.c
> @@ -1872,6 +1872,7 @@ _mesa_copy_linked_program_data(gl_shader_type type,
>        dst_gp->InputType = src->Geom.InputType;
>        dst_gp->OutputType = src->Geom.OutputType;
>        dst_gp->UsesClipDistance = src->Geom.UsesClipDistance;
> +      dst_gp->UsesEndPrimitive = src->Geom.UsesEndPrimitive;
>     }
>        break;
>     default:
> 

We set some similar flags in ir_set_program_inouts.  Specifically, I'm
thinking about UsesDFdy.  someday, it might be nice to consolidate all
the "Does the shader use X?" flags in one place.

I'm fine with your code as is, though.  Progress.