[Mesa-dev] [PATCH 2/3] mesa: build up a mask of active shader stages in a pipeline

[Timothy Arceri]

On Tue, 2015-12-08 at 10:55 +1100, Timothy Arceri wrote:
> On Mon, 2015-12-07 at 11:29 +0200, Tapani Pälli wrote:
> > This will be used for validating SSO pipeline where all active
> > stages
> > in linked programs should be in use when rendering.
> > 
> > Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> > ---
> >  src/mesa/main/mtypes.h      |  2 ++
> >  src/mesa/main/pipelineobj.c | 39
> > +++++++++++++++++++++++++++++++++++++++
> >  2 files changed, 41 insertions(+)
> > 
> > diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> > index fa7ead0..d5a22c9 100644
> > --- a/src/mesa/main/mtypes.h
> > +++ b/src/mesa/main/mtypes.h
> > @@ -2824,6 +2824,8 @@ struct gl_pipeline_object
> >     GLboolean Validated;                 /**< Pipeline Validation
> > status */
> >  
> >     GLchar *InfoLog;
> > +
> > +   uint8_t ActiveStages;                /**< Stages used,
> > (glUseProgramStages) */
> >  };
> >  
> >  /**
> > diff --git a/src/mesa/main/pipelineobj.c
> > b/src/mesa/main/pipelineobj.c
> > index 6710d0d..c510ee8 100644
> > --- a/src/mesa/main/pipelineobj.c
> > +++ b/src/mesa/main/pipelineobj.c
> > @@ -218,6 +218,43 @@ _mesa_reference_pipeline_object_(struct
> > gl_context *ctx,
> >     }
> >  }
> >  
> > +static GLenum
> > +shader_bit_from_shader_stage(gl_shader_stage stage)
> > +{
> > +   switch (stage) {
> > +   case MESA_SHADER_VERTEX:
> > +      return GL_VERTEX_SHADER_BIT;
> > +   case MESA_SHADER_FRAGMENT:
> > +      return GL_FRAGMENT_SHADER_BIT;
> > +   case MESA_SHADER_GEOMETRY:
> > +      return GL_GEOMETRY_SHADER_BIT;
> > +   case MESA_SHADER_TESS_CTRL:
> > +      return GL_TESS_CONTROL_SHADER_BIT;
> > +   case MESA_SHADER_TESS_EVAL:
> > +      return GL_TESS_EVALUATION_SHADER_BIT;
> > +   case MESA_SHADER_COMPUTE:
> > +      return GL_COMPUTE_SHADER_BIT;
> > +   default:
> > +      unreachable("bad value in
> > _mesa_shader_bit_from_shader_stage()");
> > +   }
> > +}
> > +
> > +static void
> > +update_active_pipeline_stages(struct gl_pipeline_object *pipe,
> > +                              struct gl_shader_program *shProg,
> > +                              GLbitfield stages)
> > +{
> > +   unsigned i;
> > +   for (i = 0; i < MESA_SHADER_STAGES; i++) {
> > +      if ((stages & shader_bit_from_shader_stage(i)) != 0) {
> > +         if (shProg && shProg->ActiveStages & (1 << i))
> > +            pipe->ActiveStages |= (1 << i);
> > +         else
> > +            pipe->ActiveStages &= ~(1 << i);
> > +      }
> > +   }
> 
> I think you could do most of the validation at this point which would
> reduce the amount of work required during rendering. You also have
> forgotten about GL_ALL_SHADER_BITS.

No you didn't I was just looking at to code for to long :P However
unless I'm missing something I believe my other comments are still
valid.

> 
> For example could you do something like this? 
> 
> Note: You would need to call this function after the
>  _mesa_use_shader_program() calls.
> 
> unsigned i;
> unsigned j;     
> 
> for (i = 0; i < MESA_SHADER_STAGES; i++) {
>    if (!pipe->CurrentProgram[i]) {
>       struct gl_shader_program *shProg = pipe->CurrentProgram[i];
>       for (j = 0; j < MESA_SHADER_STAGES; j++) {
>          if (!shProg->_LinkedShaders[j])
>          continue;
> 
>          /* Make sure that any shader stage is also used in the
> pipeline */
>          if (shProg != pipe->CurrentProgram[j]) {
>             pipe->ValidProgramUse = false;
>             return;
>          }
>       }
>    }
> 
>    pipe->ValidProgramUse = true;
> }
> 
> > +}
> > +
> >  /**
> >   * Bound program to severals stages of the pipeline
> >   */
> > @@ -311,6 +348,8 @@ _mesa_UseProgramStages(GLuint pipeline,
> > GLbitfield stages, GLuint program)
> >        }
> >     }
> >  
> > +   update_active_pipeline_stages(pipe, shProg, stages);
> > +
> >     /* Enable individual stages from the program as requested by
> > the
> >      * application.  If there is no shader for a requested stage in
> > the
> >      * program, _mesa_use_shader_program will enable fixed-function
> > processing
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