==== ./Mesa-10.0.3/src/glsl/linker.cpp#2 (text) ====

@@ -556,7 +556,56 @@
    prog->Geom.UsesEndPrimitive = end_primitive.end_primitive_found();
 }
 
+/**
+ * Checks if the types are the same under the rules of GLSL spec section 4.2
+ */
+bool
+are_glsl_uniform_types_same(const struct glsl_type *left,
+                            const struct glsl_type *right)
+{
+   if (left == right)
+      return true;
+
+   if (left->base_type != right->base_type)
+      return false;
+
+   if (left->is_record()) {
+      // same names
+      if (strcmp(left->name, right->name) != 0) {
+         return false;
+      }
 
+      // same number of fields
+      if (left->length != right->length) {
+         return false;
+      }
+
+      for (unsigned i = 0; i < left->length; ++i) {
+         glsl_struct_field* lf = left->fields.structure + i;
+         glsl_struct_field* rf = right->fields.structure + i;
+
+         // field name and type must be the same
+         if (strcmp(lf->name, rf->name) != 0 ||
+             !are_glsl_uniform_types_same(lf->type, rf->type) ||
+             lf->row_major != rf->row_major) {
+            return false;
+         }
+      }
+
+      // no mismatches found, must be good
+      return true;
+   }
+
+   if (left->is_array()) {
+      // same length and element type
+      return left->length == right->length &&
+         are_glsl_uniform_types_same(left->element_type(), right->element_type());
+   }
+
+   return false;
+}
+
+
 /**
  * Perform validation of global variables used across multiple shaders
  */
@@ -609,7 +658,7 @@
 		  if (var->type->length != 0) {
 		     existing->type = var->type;
 		  }
-	       } else {
+	       } else if (!are_glsl_uniform_types_same(var->type, existing->type)) {
 		  linker_error(prog, "%s `%s' declared as type "
 			       "`%s' and type `%s'\n",
 			       mode_string(var),