[Mesa-dev] [PATCH 1/2] st/glsl_to_nir: gather next_stage in shader_info

[Timothy Arceri]

On 28/02/18 03:45, Marek Olšák wrote:
> On Mon, Feb 26, 2018 at 10:43 AM, Timothy Arceri <tarceri at itsqueeze.com> wrote:
>> ---
>>   src/compiler/shader_info.h                |  5 +++++
>>   src/mesa/state_tracker/st_glsl_to_nir.cpp | 13 +++++++++++++
>>   2 files changed, 18 insertions(+)
>>
>> diff --git a/src/compiler/shader_info.h b/src/compiler/shader_info.h
>> index e7fd7dbe62..11a59ff6ac 100644
>> --- a/src/compiler/shader_info.h
>> +++ b/src/compiler/shader_info.h
>> @@ -54,6 +54,11 @@ typedef struct shader_info {
>>      /** The shader stage, such as MESA_SHADER_VERTEX. */
>>      gl_shader_stage stage;
>>
>> +   /** The shader stage in a non SSO linked program that follows this stage,
>> +     * such as MESA_SHADER_FRAGMENT.
>> +     */
>> +   gl_shader_stage next_stage;
>> +
>>      /* Number of textures used by this shader */
>>      unsigned num_textures;
>>      /* Number of uniform buffers used by this shader */
>> diff --git a/src/mesa/state_tracker/st_glsl_to_nir.cpp b/src/mesa/state_tracker/st_glsl_to_nir.cpp
>> index 765c827d93..914fd2e898 100644
>> --- a/src/mesa/state_tracker/st_glsl_to_nir.cpp
>> +++ b/src/mesa/state_tracker/st_glsl_to_nir.cpp
>> @@ -317,6 +317,19 @@ st_glsl_to_nir(struct st_context *st, struct gl_program *prog,
>>
>>      nir_shader *nir = glsl_to_nir(shader_program, stage, options);
>>
>> +   /* Set the next shader stage hint for VS and TES. */
>> +   if (!nir->info.separate_shader &&
>> +       (nir->info.stage == MESA_SHADER_VERTEX ||
>> +        nir->info.stage == MESA_SHADER_TESS_EVAL)) {
>> +
>> +      unsigned prev_stages = (1 << (prog->info.stage + 1)) - 1;
>> +      unsigned stages_mask =
>> +         ~prev_stages & shader_program->data->linked_stages;
>> +
>> +      nir->info.next_stage = stages_mask ?
>> +         (gl_shader_stage) u_bit_scan(&stages_mask) : MESA_SHADER_FRAGMENT;
> 
> ffs would be better.
> 
> Also, ureg sets ..._SHADER_FRAGMENT if st/mesa doesn't set anything
> (e.g. it's a separate shader).

Yes the ureg function does that, which is what the "stages_mask ?" above 
  does too. However separate shaders don't get set because 
ureg_set_next_shader_processor() won't get called for them.

    /* Set the next shader stage hint for VS and TES. */
    switch (procType) {
    case PIPE_SHADER_VERTEX:
    case PIPE_SHADER_TESS_EVAL:
       if (program->shader_program->SeparateShader)
          break;

       for (i = program->shader->Stage+1; i <= MESA_SHADER_FRAGMENT; i++) {
          if (program->shader_program->_LinkedShaders[i]) {
             ureg_set_next_shader_processor(
                   ureg, pipe_shader_type_from_mesa((gl_shader_stage)i));
             break;
          }
       }
       break;
    }



> 
> Marek
>