[Mesa-dev] [PATCH 30/53] mesa: don't always set _NEW_PROGRAM when linking

[Marek Olšák]

On Tue, Jan 3, 2017 at 3:43 AM, Timothy Arceri
<timothy.arceri at collabora.com> wrote:
> We only need to set it when linking was successful and the program
> being linked is currently active.
>
> The programs_in_use mask is just used as a flag for now but in
> a following patch we will use it to update the CurrentProgram
> array.
> ---
>  src/mesa/main/shaderapi.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/src/mesa/main/shaderapi.c b/src/mesa/main/shaderapi.c
> index 022afab..6c03dcb 100644
> --- a/src/mesa/main/shaderapi.c
> +++ b/src/mesa/main/shaderapi.c
> @@ -1083,10 +1083,30 @@ _mesa_link_program(struct gl_context *ctx, struct gl_shader_program *shProg)
>        return;
>     }
>
> -   FLUSH_VERTICES(ctx, _NEW_PROGRAM);
> +   unsigned programs_in_use = 0;
> +   if (ctx->_Shader)
> +      for (unsigned stage = 0; stage < MESA_SHADER_STAGES; stage++) {
> +         if (ctx->_Shader->CurrentProgram[stage] == shProg) {
> +            programs_in_use |= 1 << stage;
> +         }
> +   }
>
>     _mesa_glsl_link_shader(ctx, shProg);
>
> +   /* From section 7.3 (Program Objects) of the OpenGL 4.5 spec:
> +    *
> +    *    "If LinkProgram or ProgramBinary successfully re-links a program
> +    *     object that is active for any shader stage, then the newly generated
> +    *     executable code will be installed as part of the current rendering
> +    *     state for all shader stages where the program is active.
> +    *     Additionally, the newly generated executable code is made part of
> +    *     the state of any program pipeline for all stages where the program
> +    *     is attached."
> +    */
> +   if (shProg->data->LinkStatus && programs_in_use) {
> +      FLUSH_VERTICES(ctx, _NEW_PROGRAM);
> +   }

This doesn't seem correct. If the context has unflushed vertices,
calling FLUSH_VERTICES after linking will use the new linked program
instead of the previous program for which the vertices were submitted.

Marek