linker: Allow built-in arrays to have different sizes between shader stages

Fixes pitlit test glsl-link-varying-TexCoord (bugzilla #31650).

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index e62fe6d7e9fd4002a3ac070298da0d7da7fef9c2..d8c42ac462427397648a7707a16721222658aade 100644 (file)
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -487,14 +487,35 @@ cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
         /* Check that the types match between stages.
          */
         if (input->type != output->type) {
-           linker_error_printf(prog,
-                               "%s shader output `%s' declared as "
-                               "type `%s', but %s shader input declared "
-                               "as type `%s'\n",
-                               producer_stage, output->name,
-                               output->type->name,
-                               consumer_stage, input->type->name);
-           return false;
+           /* There is a bit of a special case for gl_TexCoord.  This
+            * built-in is unsized by default.  Appliations that variable
+            * access it must redeclare it with a size.  There is some
+            * language in the GLSL spec that implies the fragment shader
+            * and vertex shader do not have to agree on this size.  Other
+            * driver behave this way, and one or two applications seem to
+            * rely on it.
+            *
+            * Neither declaration needs to be modified here because the array
+            * sizes are fixed later when update_array_sizes is called.
+            *
+            * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
+            *
+            *     "Unlike user-defined varying variables, the built-in
+            *     varying variables don't have a strict one-to-one
+            *     correspondence between the vertex language and the
+            *     fragment language."
+            */
+           if (!output->type->is_array()
+               || (strncmp("gl_", output->name, 3) != 0)) {
+              linker_error_printf(prog,
+                                  "%s shader output `%s' declared as "
+                                  "type `%s', but %s shader input declared "
+                                  "as type `%s'\n",
+                                  producer_stage, output->name,
+                                  output->type->name,
+                                  consumer_stage, input->type->name);
+              return false;
+           }
         }
 
         /* Check that all of the qualifiers match between stages.