[Mesa-dev] [PATCH 08/10] glsl: A shader cannot redefine or overload built-in functions in GLSL ES 3.00

[Ian Romanick]

Oof.  I'd really like to have Ken review this code.  He's the expert in
this area...

On 12/01/2014 05:04 AM, Eduardo Lima Mitev wrote:
> From: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> 
> Create a new search function to look for matching built-in functions by name
> and use it for built-in function redefinition or overload in GLSL ES 3.00.
> 
> GLSL ES 3.0 spec, chapter 6.1 "Function Definitions", page 71
> 
> "A shader cannot redefine or overload built-in functions."
> 
> In case of GLSL ES 1.0 spec, chapter 6.1 "Function Definitions", page 54
> 
> "Function names can be overloaded. This allows the same function name to be
> used for multiple functions, as long as the argument list types differ. If
> functions’ names and argument types match, then their return type and
> parameter qualifiers must also match. Function signature matching is based on
> parameter type only, no qualifiers are used. Overloading is used heavily in the
> built-in functions. When overloaded functions (or indeed any functions) are
> resolved, an exact match for the function's signature is sought. This includes
> exact match of array size as well. No promotion or demotion of the return type
> or input argument types is done. All expected combination of inputs and
> outputs must be defined as separate functions."
> 
> So this check is specific to GLSL ES 3.00.
> 
> This patch fixes the following dEQP tests:
> 
> dEQP-GLES3.functional.shaders.functions.invalid.overload_builtin_function_vertex
> dEQP-GLES3.functional.shaders.functions.invalid.overload_builtin_function_fragment
> dEQP-GLES3.functional.shaders.functions.invalid.redefine_builtin_function_vertex
> dEQP-GLES3.functional.shaders.functions.invalid.redefine_builtin_function_fragment
> 
> No piglit regressions.
> 
> Signed-off-by: Samuel Iglesias Gonsalvez <siglesias at igalia.com>
> ---
>  src/glsl/ast_to_hir.cpp        | 22 ++++++++++++++++++++++
>  src/glsl/builtin_functions.cpp | 11 +++++++++++
>  src/glsl/ir.h                  |  4 ++++
>  3 files changed, 37 insertions(+)
> 
> diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
> index fe1e129..b7074bc 100644
> --- a/src/glsl/ast_to_hir.cpp
> +++ b/src/glsl/ast_to_hir.cpp
> @@ -4167,6 +4167,28 @@ ast_function::hir(exec_list *instructions,
>                 return NULL;
>              }
>           }
> +      } else {
> +         /* From GLSL ES 3.0 spec, chapter 6.1 "Function Definitions", page 71:
> +          *
> +          * "A shader cannot redefine or overload built-in functions."
> +          *
> +          * While in GLSL ES 1.0 spec, chapter 6.1 "Function Definitions", page
> +          * 54, this is allowed:
> +          *
> +          * "Function names can be overloaded. [...] Overloading is used heavily
> +          * in the built-in functions."
> +          *
> +          */
> +         if (state->es_shader && state->language_version >= 300) {
> +            /* Local shader has no exact candidates; check the built-ins. */
> +            _mesa_glsl_initialize_builtin_functions();
> +            if (_mesa_glsl_find_builtin_function_by_name(state, name)) {
> +               YYLTYPE loc = this->get_location();
> +               _mesa_glsl_error(& loc, state,
> +                                "A shader cannot redefine or overload built-in "
> +                                "function `%s' in GLSL ES 3.00", name);
> +            }
> +         }
>        }
>     }
>  
> diff --git a/src/glsl/builtin_functions.cpp b/src/glsl/builtin_functions.cpp
> index bb7fbcd..f5052d3 100644
> --- a/src/glsl/builtin_functions.cpp
> +++ b/src/glsl/builtin_functions.cpp
> @@ -4618,6 +4618,17 @@ _mesa_glsl_find_builtin_function(_mesa_glsl_parse_state *state,
>     return s;
>  }
>  
> +ir_function *
> +_mesa_glsl_find_builtin_function_by_name(_mesa_glsl_parse_state *state,
> +                                         const char *name)
> +{
> +   ir_function * f;
> +   mtx_lock(&builtins_lock);
> +   f = builtins.shader->symbols->get_function(name);
> +   mtx_unlock(&builtins_lock);
> +   return f;
> +}
> +
>  gl_shader *
>  _mesa_glsl_get_builtin_function_shader()
>  {
> diff --git a/src/glsl/ir.h b/src/glsl/ir.h
> index a0f48b2..f2d8269 100644
> --- a/src/glsl/ir.h
> +++ b/src/glsl/ir.h
> @@ -2417,6 +2417,10 @@ extern ir_function_signature *
>  _mesa_glsl_find_builtin_function(_mesa_glsl_parse_state *state,
>                                   const char *name, exec_list *actual_parameters);
>  
> +extern ir_function *
> +_mesa_glsl_find_builtin_function_by_name(_mesa_glsl_parse_state *state,
> +                                         const char *name);
> +
>  extern gl_shader *
>  _mesa_glsl_get_builtin_function_shader(void);
>  
>