[Mesa-dev] [PATCH] glsl/linker: Check the subroutine associated functions names

[Tapani Pälli]

On 10/1/18 5:03 PM, Vadym Shovkoplias wrote:
>  From Section 6.1.2 (Subroutines) of the GLSL 4.00 specification
> 
>      "A program will fail to compile or link if any shader
>       or stage contains two or more functions with the same
>       name if the name is associated with a subroutine type."
> 
> Fixes:
>      * no-overloads.vert
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108109
> Signed-off-by: Vadym Shovkoplias <vadym.shovkoplias at globallogic.com>
> ---
>   src/compiler/glsl/linker.cpp | 40 ++++++++++++++++++++++++++++++++++++
>   1 file changed, 40 insertions(+)
> 
> diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
> index 3fde7e78d3..d0d017c7ff 100644
> --- a/src/compiler/glsl/linker.cpp
> +++ b/src/compiler/glsl/linker.cpp
> @@ -4639,6 +4639,45 @@ link_assign_subroutine_types(struct gl_shader_program *prog)
>      }
>   }
>   
> +static void
> +verify_subroutine_associated_funcs(struct gl_shader_program *prog)
> +{
> +   unsigned mask = prog->data->linked_stages;
> +   while (mask) {
> +      const int i = u_bit_scan(&mask);
> +      gl_program *p = prog->_LinkedShaders[i]->Program;
> +      glsl_symbol_table *symbols = prog->_LinkedShaders[i]->symbols;
> +
> +      /*
> +       * From OpenGL ES Shading Language 4.00 specification
> +       * (6.1.2 Subroutines):
> +       *     "A program will fail to compile or link if any shader
> +       *     or stage contains two or more functions with the same
> +       *     name if the name is associated with a subroutine type."
> +       */
> +      for (unsigned j = 0; j < p->sh.NumSubroutineFunctions; j++) {
> +         unsigned definitions = 0;
> +         char *name = p->sh.SubroutineFunctions[j].name;
> +         ir_function *fn = symbols->get_function(name);
> +
> +         /* Calculate number of function definitions with the same name */
> +         foreach_in_list(ir_function_signature, sig, &fn->signatures) {
> +            if (sig->is_defined)
> +               definitions++;

You can just error out here, no need to calculate further.

I'm wondering a bit though should we fail here even if that function was 
not used at all (optimized out)? I can see that the Piglit test does not 
have a call to the function defined.


> +         }
> +
> +         if (definitions > 1) {
> +            linker_error(prog, "%s shader contains %u function "
> +                  "definitions with name `%s', which is associated with"
> +                  " a subroutine type.\n",
> +                  _mesa_shader_stage_to_string(i), definitions, fn->name);
> +            return;
> +         }
> +      }
> +   }
> +}
> +
> +
>   static void
>   set_always_active_io(exec_list *ir, ir_variable_mode io_mode)
>   {
> @@ -5024,6 +5063,7 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
>   
>      check_explicit_uniform_locations(ctx, prog);
>      link_assign_subroutine_types(prog);
> +   verify_subroutine_associated_funcs(prog);
>   
>      if (!prog->data->LinkStatus)
>         goto done;
>