[Mesa-dev] [PATCH 3/4] glsl: Validate qualifiers on VS color outputs with FS color inputs

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

The vertex shader color outputs (gl_FrontColor, gl_BackColor,
gl_FrontSecondaryColor, and gl_BackSecondaryColor) don't have the same
names as the matching fragment shader color inputs (gl_Color and
gl_SecondaryColor).  As a result, the qualifiers on them were not being
properly cross validated.

Full spec compliance required ir_variable::used and
ir_variable::assigned be set properly.  Without the preceeding patch,
which fixes the ::clone method to copy them, this will not be the case.

Fixes all of the previously failing piglit
spec/glsl-1.30/linker/interpolation-qualifiers tests.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=47755
---
 src/glsl/link_varyings.cpp | 53 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 50 insertions(+), 3 deletions(-)

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index a1899f7..7a61b1a 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -132,6 +132,29 @@ cross_validate_types_and_qualifiers(struct gl_shader_program *prog,
 }
 
 /**
+ * Validate front and back color outputs against single color input
+ */
+static void
+cross_validate_front_and_back_color(struct gl_shader_program *prog,
+                                    const ir_variable *input,
+                                    const ir_variable *front_color,
+                                    const ir_variable *back_color,
+                                    GLenum consumer_type,
+                                    const char *consumer_stage,
+                                    const char *producer_stage)
+{
+   if (front_color != NULL && front_color->assigned)
+      cross_validate_types_and_qualifiers(prog, input, front_color,
+                                          consumer_type, consumer_stage,
+                                          producer_stage);
+
+   if (back_color != NULL && back_color->assigned)
+      cross_validate_types_and_qualifiers(prog, input, back_color,
+                                          consumer_type, consumer_stage,
+                                          producer_stage);
+}
+
+/**
  * Validate that outputs from one stage match inputs of another
  */
 void
@@ -170,11 +193,35 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
       if ((input == NULL) || (input->mode != ir_var_shader_in))
 	 continue;
 
-      ir_variable *const output = parameters.get_variable(input->name);
-      if (output != NULL) {
-         cross_validate_types_and_qualifiers(prog, input, output,
+      if (strcmp(input->name, "gl_Color") == 0 && input->used) {
+         const ir_variable *const front_color =
+            parameters.get_variable("gl_FrontColor");
+
+         const ir_variable *const back_color =
+            parameters.get_variable("gl_BackColor");
+
+         cross_validate_front_and_back_color(prog, input,
+                                             front_color, back_color,
                                              consumer->Type, consumer_stage,
                                              producer_stage);
+      } else if (strcmp(input->name, "gl_SecondaryColor") == 0 && input->used) {
+         const ir_variable *const front_color =
+            parameters.get_variable("gl_FrontSecondaryColor");
+
+         const ir_variable *const back_color =
+            parameters.get_variable("gl_BackSecondaryColor");
+
+         cross_validate_front_and_back_color(prog, input,
+                                             front_color, back_color,
+                                             consumer->Type, consumer_stage,
+                                             producer_stage);
+      } else {
+         ir_variable *const output = parameters.get_variable(input->name);
+         if (output != NULL) {
+            cross_validate_types_and_qualifiers(prog, input, output,
+                                                consumer->Type, consumer_stage,
+                                                producer_stage);
+         }
       }
    }
 }
-- 
1.8.1.4