[Mesa-dev] [PATCH] shader-db: simplify and improve SSO handling

[Kenneth Graunke]

On Wednesday, July 18, 2018 4:22:41 AM PDT Timothy Arceri wrote:
> This does two things:
> 
> 1. Allows cross shader optimisations to be preformed on SSO
>    programs that contain more than one stage (seems like I
>    don't have any of these in my shader-db collection).
> 
> 2. Allows us to write compilation errors to stderr. With this
>    change I discovered a Deus Ex: MD shader was failing to
>    compile (I've reported it to Feral).
> ---
>  run.c | 23 ++++-------------------
>  1 file changed, 4 insertions(+), 19 deletions(-)
> 
> diff --git a/run.c b/run.c
> index fdb610d..aa64d2c 100644
> --- a/run.c
> +++ b/run.c
> @@ -809,27 +809,12 @@ main(int argc, char **argv)
>              if (num_shaders == 1 && type != TYPE_VP && type != TYPE_FP)
>                  use_separate_shader_objects = true;
>  
> -            if (use_separate_shader_objects) {
> -                for (unsigned i = 0; i < num_shaders; i++) {
> -                    const char *const_text;
> -                    unsigned size = shader[i].length + 1;
> -                    /* Using alloca crashes in the GLSL compiler.  */
> -                    char *text = malloc(size);
> -                    memset(text, 0, size);
> -
> -                    /* Make it zero-terminated. */
> -                    memcpy(text, shader[i].text, shader[i].length);
> -                    text[shader[i].length] = 0;
> -
> -                    const_text = text;
> -                    GLuint prog = glCreateShaderProgramv(shader[i].type, 1,
> -                                                         &const_text);
> -                    glDeleteProgram(prog);
> -                    free(text);
> -                }
> -            } else if (type == TYPE_CORE || type == TYPE_COMPAT || type == TYPE_ES) {
> +            if (type == TYPE_CORE || type == TYPE_COMPAT || type == TYPE_ES) {
>                  GLuint prog = glCreateProgram();
>  
> +                if (use_separate_shader_objects)
> +                   glProgramParameteri(prog, GL_PROGRAM_SEPARABLE, GL_TRUE);
> +
>                  for (unsigned i = 0; i < num_shaders; i++) {
>                      GLuint s = glCreateShader(shader[i].type);
>                      glShaderSource(s, 1, &shader[i].text, &shader[i].length);
> 

This looks good to me.  It looks like MESA_SHADER_CAPTURE_PATH would
dump multiple shaders to the same file, with "SSO ENABLED" set, if a
SSO program contained multiple shader stages.  At which point, we'd
want to compile them together...which your patch arranges for.

If there's only one stage in a program, then your patch should be
equivalent.

Also, it's much less code.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>
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