[Mesa-dev] [PATCH] glsl: s/unsigned/glsl_base_type/ in glsl type code

[Ian Romanick]

On 11/06/2017 01:00 PM, Brian Paul wrote:
> Declare glsl_type::sampled_type as glsl_base_type as we do for the
> base_type field.  And make base_type a bitfield to save a few bytes.

Hmm... I have mixed feelings about this.  I made a conscious decision to
have base_type be "full size" because it's used a lot.  I suspect there
will be some increase in code size across this change.  There's probably
also some performance difference, but it may not be enough to be
measurable.  I do like actually using type names. :)

As new base types were added, sampled_type remained 2 bits because GLSL
only allows float, int and uint.  This is the reason GLSL_TYPE_UINT64
and GLSL_TYPE_INT64 are not grouped with GLSL_TYPE_UINT and GLSL_TYPE_INT.

I wonder if it might be more compact (in terms of generated code) to
make both fields 8 bits and group them together.

> Update glsl_type constructor to take glsl_base_type intead of unsigned
                                                      ^^^^^^ instead

> and pass GLSL_TYPE_VOID instead of zero.
> 
> No Piglit regressions with llvmpipe.
> ---
>  src/compiler/glsl_types.cpp | 14 +++++++-------
>  src/compiler/glsl_types.h   | 14 +++++++-------
>  2 files changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/src/compiler/glsl_types.cpp b/src/compiler/glsl_types.cpp
> index 704b63c..1d20b02 100644
> --- a/src/compiler/glsl_types.cpp
> +++ b/src/compiler/glsl_types.cpp
> @@ -52,7 +52,7 @@ glsl_type::glsl_type(GLenum gl_type,
>     gl_type(gl_type),
>     base_type(base_type),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing(0), interface_row_major(0),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing(0), interface_row_major(0),
>     vector_elements(vector_elements), matrix_columns(matrix_columns),
>     length(0)
>  {
> @@ -79,7 +79,7 @@ glsl_type::glsl_type(GLenum gl_type,
>  
>  glsl_type::glsl_type(GLenum gl_type, glsl_base_type base_type,
>                       enum glsl_sampler_dim dim, bool shadow, bool array,
> -                     unsigned type, const char *name) :
> +                     glsl_base_type type, const char *name) :
>     gl_type(gl_type),
>     base_type(base_type),
>     sampler_dimensionality(dim), sampler_shadow(shadow),
> @@ -104,7 +104,7 @@ glsl_type::glsl_type(const glsl_struct_field *fields, unsigned num_fields,
>     gl_type(0),
>     base_type(GLSL_TYPE_STRUCT),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing(0), interface_row_major(0),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing(0), interface_row_major(0),
>     vector_elements(0), matrix_columns(0),
>     length(num_fields)
>  {
> @@ -133,7 +133,7 @@ glsl_type::glsl_type(const glsl_struct_field *fields, unsigned num_fields,
>     gl_type(0),
>     base_type(GLSL_TYPE_INTERFACE),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing((unsigned) packing),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing((unsigned) packing),
>     interface_row_major((unsigned) row_major),
>     vector_elements(0), matrix_columns(0),
>     length(num_fields)
> @@ -161,7 +161,7 @@ glsl_type::glsl_type(const glsl_type *return_type,
>     gl_type(0),
>     base_type(GLSL_TYPE_FUNCTION),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing(0), interface_row_major(0),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing(0), interface_row_major(0),
>     vector_elements(0), matrix_columns(0),
>     length(num_params)
>  {
> @@ -193,7 +193,7 @@ glsl_type::glsl_type(const char *subroutine_name) :
>     gl_type(0),
>     base_type(GLSL_TYPE_SUBROUTINE),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing(0), interface_row_major(0),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing(0), interface_row_major(0),
>     vector_elements(1), matrix_columns(1),
>     length(0)
>  {
> @@ -444,7 +444,7 @@ _mesa_glsl_release_types(void)
>  glsl_type::glsl_type(const glsl_type *array, unsigned length) :
>     base_type(GLSL_TYPE_ARRAY),
>     sampler_dimensionality(0), sampler_shadow(0), sampler_array(0),
> -   sampled_type(0), interface_packing(0), interface_row_major(0),
> +   sampled_type(GLSL_TYPE_VOID), interface_packing(0), interface_row_major(0),
>     vector_elements(0), matrix_columns(0),
>     length(length), name(NULL)
>  {
> diff --git a/src/compiler/glsl_types.h b/src/compiler/glsl_types.h
> index 0b4a66c..6e2d6cc 100644
> --- a/src/compiler/glsl_types.h
> +++ b/src/compiler/glsl_types.h
> @@ -145,16 +145,16 @@ enum {
>  
>  struct glsl_type {
>     GLenum gl_type;
> -   glsl_base_type base_type;
> +   glsl_base_type base_type:6;
>  
>     unsigned sampler_dimensionality:4; /**< \see glsl_sampler_dim */
>     unsigned sampler_shadow:1;
>     unsigned sampler_array:1;
> -   unsigned sampled_type:2;    /**< Type of data returned using this
> -				* sampler or image.  Only \c
> -				* GLSL_TYPE_FLOAT, \c GLSL_TYPE_INT,
> -				* and \c GLSL_TYPE_UINT are valid.
> -				*/
> +   glsl_base_type sampled_type:6; /**< Type of data returned using this
> +                                   * sampler or image.  Only \c
> +                                   * GLSL_TYPE_FLOAT, \c GLSL_TYPE_INT,
> +                                   * and \c GLSL_TYPE_UINT are valid.
> +                                   */
>     unsigned interface_packing:2;
>     unsigned interface_row_major:1;
>  
> @@ -874,7 +874,7 @@ private:
>     /** Constructor for sampler or image types */
>     glsl_type(GLenum gl_type, glsl_base_type base_type,
>  	     enum glsl_sampler_dim dim, bool shadow, bool array,
> -	     unsigned type, const char *name);
> +	     glsl_base_type type, const char *name);
>  
>     /** Constructor for record types */
>     glsl_type(const glsl_struct_field *fields, unsigned num_fields,
>