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

[Eduardo Lima Mitev]

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);
 
-- 
2.1.3