[Mesa-dev] [PATCH 05/10] glsl/linker: assign explicit uniform locations

[Ian Romanick]

On 04/09/2014 02:56 AM, Tapani Pälli wrote:
> Patch refactors the existing uniform processing so explicit locations
> are taken in to account during variable processing. These locations
> are temporarily stored in gl_uniform_storage before actual locations
> are set.
> 
> The 'remap_location' variable in gl_uniform_storage is changed to be
> signed so that we can use 0 as a valid explicit location and '-1' as
> identifier that no explicit location has been defined.
> 
> When locations are set, UniformRemapTable is first populated with
> uniforms that have explicit location set (inactive and actives ones),
> rest are put after explicit location slots.
> 
> Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> ---
>  src/glsl/ir_uniform.h      |  5 +++--
>  src/glsl/link_uniforms.cpp | 56 +++++++++++++++++++++++++++++++++++++++++-----
>  2 files changed, 54 insertions(+), 7 deletions(-)
> 
> diff --git a/src/glsl/ir_uniform.h b/src/glsl/ir_uniform.h
> index 3508509..9dc4a8e 100644
> --- a/src/glsl/ir_uniform.h
> +++ b/src/glsl/ir_uniform.h
> @@ -181,9 +181,10 @@ struct gl_uniform_storage {
>  
>     /**
>      * The 'base location' for this uniform in the uniform remap table. For
> -    * arrays this is the first element in the array.
> +    * arrays this is the first element in the array. It needs to be signed
> +    * so that we can use 0 as valid location and -1 as initial value
>      */
> -   unsigned remap_location;
> +   int remap_location;

You could use ~0u instead of -1, right?  A #define for the magic value
will also help.

>  };
>  
>  #ifdef __cplusplus
> diff --git a/src/glsl/link_uniforms.cpp b/src/glsl/link_uniforms.cpp
> index 29dc0b1..0f99082 100644
> --- a/src/glsl/link_uniforms.cpp
> +++ b/src/glsl/link_uniforms.cpp
> @@ -387,6 +387,9 @@ public:
>     void set_and_process(struct gl_shader_program *prog,
>  			ir_variable *var)
>     {
> +      current_var = var;
> +      field_counter = 0;
> +
>        ubo_block_index = -1;
>        if (var->is_in_uniform_block()) {
>           if (var->is_interface_instance() && var->type->is_array()) {
> @@ -543,6 +546,22 @@ private:
>           return;
>        }
>  
> +      /* Assign explicit locations. */
> +      if (current_var->data.explicit_location) {
> +         /* Set sequential locations for struct fields. */
> +         if (current_var->type->is_record()) {

I think you can accomplish the same thing with record_type != NULL.

> +            const unsigned entries = MAX2(1, this->uniforms[id].array_elements);
> +            this->uniforms[id].remap_location =
> +               current_var->data.location + field_counter;
> +               field_counter += entries;

Weird indentation.

> +         } else {
> +            this->uniforms[id].remap_location = current_var->data.location;
> +         }
> +      } else {
> +         /* Initialize to -1 to indicate that no explicit location is set */
> +         this->uniforms[id].remap_location = -1;
> +      }
> +
>        this->uniforms[id].name = ralloc_strdup(this->uniforms, name);
>        this->uniforms[id].type = base_type;
>        this->uniforms[id].initialized = 0;
> @@ -598,6 +617,17 @@ public:
>     gl_texture_index targets[MAX_SAMPLERS];
>  
>     /**
> +    * Current variable being processed.
> +    */
> +   ir_variable *current_var;
> +
> +   /**
> +    * Field counter is used to take care that uniform structures
> +    * with explicit locations get sequential locations.
> +    */
> +   unsigned field_counter;
> +
> +   /**
>      * Mask of samplers used by the current shader stage.
>      */
>     unsigned shader_samplers_used;
> @@ -799,10 +829,6 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
>     prog->UniformStorage = NULL;
>     prog->NumUserUniformStorage = 0;
>  
> -   ralloc_free(prog->UniformRemapTable);
> -   prog->UniformRemapTable = NULL;
> -   prog->NumUniformRemapTable = 0;
> -
>     if (prog->UniformHash != NULL) {
>        prog->UniformHash->clear();
>     } else {
> @@ -915,9 +941,29 @@ link_assign_uniform_locations(struct gl_shader_program *prog)
>               sizeof(prog->_LinkedShaders[i]->SamplerTargets));
>     }
>  
> -   /* Build the uniform remap table that is used to set/get uniform locations */
> +   /* Reserve all the explicit locations of the active uniforms. */
> +   for (unsigned i = 0; i < num_user_uniforms; i++) {
> +      if (uniforms[i].remap_location != -1) {
> +         /* How many new entries for this uniform? */
> +         const unsigned entries = MAX2(1, uniforms[i].array_elements);
> +
> +         /* Set remap table entries point to correct gl_uniform_storage. */
> +         for (unsigned j = 0; j < entries; j++) {
> +            unsigned element_loc = uniforms[i].remap_location + j;
> +            assert(prog->UniformRemapTable[element_loc] ==
> +                   (gl_uniform_storage *) -1);
> +            prog->UniformRemapTable[element_loc] = &uniforms[i];
> +         }
> +      }
> +   }
> +
> +   /* Reserve locations for rest of the uniforms. */
>     for (unsigned i = 0; i < num_user_uniforms; i++) {
>  
> +      /* Explicit ones have been set already. */
> +      if (uniforms[i].remap_location != -1)
> +         continue;
> +
>        /* how many new entries for this uniform? */
>        const unsigned entries = MAX2(1, uniforms[i].array_elements);
>  
>