[Mesa-dev] [PATCH 3/3] glsl/linker: validate explicit locations for SSO programs

[Iago Toral]

On Fri, 2017-10-20 at 13:07 +0200, Iago Toral wrote:
> On Fri, 2017-10-20 at 22:03 +1100, Timothy Arceri wrote:
> > 
> > On 20/10/17 21:46, Iago Toral Quiroga wrote:
> > > ---
> > >   src/compiler/glsl/link_varyings.cpp | 53
> > > +++++++++++++++++++++++++++++++++++++
> > >   src/compiler/glsl/link_varyings.h   |  4 +++
> > >   src/compiler/glsl/linker.cpp        |  6 +++++
> > >   3 files changed, 63 insertions(+)
> > > 
> > > diff --git a/src/compiler/glsl/link_varyings.cpp
> > > b/src/compiler/glsl/link_varyings.cpp
> > > index dffb4f98df..d7e407184d 100644
> > > --- a/src/compiler/glsl/link_varyings.cpp
> > > +++ b/src/compiler/glsl/link_varyings.cpp
> > > @@ -599,6 +599,59 @@ validate_explicit_variable_location(struct
> > > gl_context *ctx,
> > >   }
> > >   
> > >   /**
> > > + * Validate explicit locations for SSO programs. For non-SSO
> > > programs this
> > > + * is alreadty done in cross_validate_outputs_to_inputs().
> > > + */
> > > +void
> > > +validate_sso_explicit_locations(struct gl_context *ctx,
> > > +                                struct gl_shader_program *prog)
> > > +{
> > > +   assert(prog->SeparateShader);
> > > +   struct explicit_location_info
> > > explicit_locations_in[MAX_VARYINGS_INCL_PATCH][4];
> > > +   struct explicit_location_info
> > > explicit_locations_out[MAX_VARYINGS_INCL_PATCH][4];
> > > +
> > > +   for (unsigned i = 0; i <= MESA_SHADER_FRAGMENT; i++) {
> > > +      if (prog->_LinkedShaders[i] == NULL)
> > > +         continue;
> > > +
> > > +      gl_linked_shader *sh = prog->_LinkedShaders[i];
> > > +
> > > +      memset(explicit_locations_in, 0,
> > > sizeof(explicit_locations_in));
> > > +      memset(explicit_locations_out, 0,
> > > sizeof(explicit_locations_out));
> > > +
> > > +      foreach_in_list(ir_instruction, node, sh->ir) {
> > > +         ir_variable *const var = node->as_variable();
> > > +
> > > +         if (var == NULL ||
> > > +             !var->data.explicit_location ||
> > > +             var->data.location < VARYING_SLOT_VAR0 ||
> > > +             (var->data.mode != ir_var_shader_in &&
> > > +              var->data.mode != ir_var_shader_out))
> > > +            continue;
> > > +
> > > +         /* Vertex shader inputs and fragment shader outputs are
> > > validated
> > > +          * in assign_attribute_or_color_locations, skip them.
> > > +          */
> > > +         if (sh->Stage == MESA_SHADER_FRAGMENT &&
> > > +             var->data.mode == ir_var_shader_out)
> > > +            continue;
> > > +
> > > +         if (sh->Stage == MESA_SHADER_VERTEX &&
> > > +             var->data.mode == ir_var_shader_in)
> > > +            continue;
> > > +
> > > +         if (!validate_explicit_variable_location(
> > > +               ctx,
> > > +               var->data.mode == ir_var_shader_in ?
> > > explicit_locations_in :
> > > +                                                    explicit_loc
> > > at
> > > ions_out,
> > > +               var, prog, sh)) {
> > > +            return;
> > > +         }
> > > +      }
> > > +   }
> > > +}
> > > +
> > > +/**
> > >    * Validate that outputs from one stage match inputs of another
> > >    */
> > >   void
> > > diff --git a/src/compiler/glsl/link_varyings.h
> > > b/src/compiler/glsl/link_varyings.h
> > > index 081b04ea38..e8486208a2 100644
> > > --- a/src/compiler/glsl/link_varyings.h
> > > +++ b/src/compiler/glsl/link_varyings.h
> > > @@ -300,6 +300,10 @@ link_varyings(struct gl_shader_program
> > > *prog,
> > > unsigned first, unsigned last,
> > >                 struct gl_context *ctx, void *mem_ctx);
> > >   
> > >   void
> > > +validate_sso_explicit_locations(struct gl_context *ctx,
> > > +                                struct gl_shader_program *prog);
> > > +
> > > +void
> > >   cross_validate_outputs_to_inputs(struct gl_context *ctx,
> > >                                    struct gl_shader_program
> > > *prog,
> > >                                    gl_linked_shader *producer,
> > > diff --git a/src/compiler/glsl/linker.cpp
> > > b/src/compiler/glsl/linker.cpp
> > > index 3798309678..cba14f940b 100644
> > > --- a/src/compiler/glsl/linker.cpp
> > > +++ b/src/compiler/glsl/linker.cpp
> > > @@ -4938,6 +4938,12 @@ link_shaders(struct gl_context *ctx,
> > > struct
> > > gl_shader_program *prog)
> > >         prev = i;
> > >      }
> > >   
> > > +   /* Validate location aliasing for SSO programs (this is done
> > > during
> > > +    * cross_validate_outputs_to_inputs for non-SSO programs).
> > > +    */
> > > +   if (prog->SeparateShader)
> > > +      validate_sso_explicit_locations(ctx, prog);
> > 
> > Somewhere in link shaders we already calculate the first and last
> > shader 
> > stages. I think we should probably pass those to this function and
> > then 
> > only run the validation on the input of the first and output of
> > the 
> > last, otherwise we are re-validating things the are already covered
> > by 
> > the non-sso checks.
> 
> Aha, good point, thanks. I'll look into that.

Actually, I think maybe I read your proposal too fast :). The only
place where we check for this for non-sso paths is
cross_validate_outputs_to_inputs() and we don't call that for SSO
programs, so there is no chance that we are re-validating anything
here. Am I missing something?

> Iago
> 
> > > +
> > >      /* Cross-validate uniform blocks between shader stages */
> > >      validate_interstage_uniform_blocks(prog, prog-
> > > > _LinkedShaders);
> > > 
> > >      if (!prog->data->LinkStatus)
> > >