glsl: Check that interpolation quals only apply to vertex ins and fragment outs

The check is performed only in GLSL versions >= 1.30.

Fixes the following Piglit tests:
* spec/glsl-1.30/compiler/interpolation-qualifiers/fs-smooth-02.frag
* spec/glsl-1.30/compiler/interpolation-qualifiers/vs-smooth-01.vert

1 files changed, 35 insertions, 0 deletions

diff --git a/src/glsl/ast_to_hir.cpp b/src/glsl/ast_to_hir.cpp
index a2edb6a27cf..e5a21fd8168 100644
--- a/src/glsl/ast_to_hir.cpp
+++ b/src/glsl/ast_to_hir.cpp
@@ -2303,6 +2303,41 @@ ast_declarator_list::hir(exec_list *instructions,
       }
 
 
+      /* Interpolation qualifiers can only apply to vertex shader outputs and
+       * fragment shader inputs.
+       *
+       * From page 29 (page 35 of the PDF) of the GLSL 1.30 spec:
+       *    "Outputs from a vertex shader (out) and inputs to a fragment
+       *    shader (in) can be further qualified with one or more of these
+       *    interpolation qualifiers"
+       */
+      if (state->language_version >= 130
+          && this->type->qualifier.has_interpolation()) {
+
+         const char *i = this->type->qualifier.interpolation_string();
+         assert(i != NULL);
+
+         switch (state->target) {
+         case vertex_shader:
+            if (this->type->qualifier.flags.q.in) {
+               _mesa_glsl_error(&loc, state,
+                                "qualifier '%s' cannot be applied to vertex "
+                                "shader inputs", i);
+            }
+            break;
+         case fragment_shader:
+            if (this->type->qualifier.flags.q.out) {
+               _mesa_glsl_error(&loc, state,
+                                "qualifier '%s' cannot be applied to fragment "
+                                "shader outputs", i);
+            }
+            break;
+         default:
+            assert(0);
+         }
+      }
+
+
       /* Process the initializer and add its instructions to a temporary
        * list.  This list will be added to the instruction stream (below) after
        * the declaration is added.  This is done because in some cases (such as