glsl: Handle centroid qualifier ordering in C code, not the parser.

The GL_ARB_shading_language_420pack extension/GLSL 4.20 split centroid
off into a new category, "auxiliary storage qualifiers," and allow these
to be placed anywhere in the series.  So we have to stop recognizing
"centroid in"/"centroid out"/"centroid varying" in the grammar and get
more creative.

The same approach used before works here, too.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>

src/glsl/glsl_parser.yy

@@ -162,6 +162,7 @@ static void yyerror(YYLTYPE *loc, _mesa_glsl_parse_state *st, const char *msg)
 %type <node> simple_statement
 %type <n> precision_qualifier
 %type <type_qualifier> type_qualifier
+%type <type_qualifier> auxiliary_storage_qualifier
 %type <type_qualifier> storage_qualifier
 %type <type_qualifier> interpolation_qualifier
 %type <type_qualifier> layout_qualifier
@@ -1325,6 +1326,7 @@ type_qualifier:
       memset(& $$, 0, sizeof($$));
       $$.flags.q.invariant = 1;
    }
+   | auxiliary_storage_qualifier
    | storage_qualifier
    | interpolation_qualifier
    | layout_qualifier
@@ -1338,13 +1340,13 @@ type_qualifier:
     * In GLSL 4.20, these can be specified in any order.  In earlier versions,
     * they appear in this order (see GLSL 1.50 section 4.7 & comments below):
     *
-    *    invariant interpolation storage precision  ...or...
+    *    invariant interpolation auxiliary storage precision  ...or...
     *    layout storage precision
     *
     * Each qualifier's rule ensures that the accumulated qualifiers on the right
     * side don't contain any that must appear on the left hand side.
     * For example, when processing a storage qualifier, we check that there are
-    * no interpolation, layout, or invariant qualifiers to the right.
+    * no auxiliary, interpolation, layout, or invariant qualifiers to the right.
     */
    | INVARIANT type_qualifier
    {
@@ -1410,6 +1412,20 @@ type_qualifier:
       $$ = $1;
       $$.merge_qualifier(&@1, state, $2);
    }
+   | auxiliary_storage_qualifier type_qualifier
+   {
+      if ($2.has_auxiliary_storage()) {
+         _mesa_glsl_error(&@1, state,
+                          "Duplicate auxiliary storage qualifier (centroid).\n");
+      }
+
+      if ($2.flags.q.invariant || $2.has_interpolation() || $2.has_layout()) {
+         _mesa_glsl_error(&@1, state, "Auxiliary storage qualifiers must come "
+                          "just before storage qualifiers.\n");
+      }
+      $$ = $1;
+      $$.flags.i |= $2.flags.i;
+   }
    | storage_qualifier type_qualifier
    {
       /* Section 4.3 of the GLSL 1.20 specification states:
@@ -1420,9 +1436,11 @@ type_qualifier:
          _mesa_glsl_error(&@1, state, "Duplicate storage qualifier.\n");
 
       if (!state->ARB_shading_language_420pack_enable &&
-          ($2.flags.q.invariant || $2.has_interpolation() || $2.has_layout())) {
+          ($2.flags.q.invariant || $2.has_interpolation() || $2.has_layout() ||
+           $2.has_auxiliary_storage())) {
          _mesa_glsl_error(&@1, state, "Storage qualifiers must come after "
-                          "invariant, interpolation, and layout qualifiers.\n");
+                          "invariant, interpolation, layout and auxiliary "
+                          "storage qualifiers.\n");
       }
 
       $$ = $1;
@@ -1441,6 +1459,14 @@ type_qualifier:
    }
    ;
 
+auxiliary_storage_qualifier:
+   CENTROID
+   {
+      memset(& $$, 0, sizeof($$));
+      $$.flags.q.centroid = 1;
+   }
+   /* TODO: "sample" and "patch" also go here someday. */
+
 storage_qualifier:
    CONST_TOK
    {
@@ -1457,12 +1483,6 @@ storage_qualifier:
       memset(& $$, 0, sizeof($$));
       $$.flags.q.varying = 1;
    }
-   | CENTROID VARYING
-   {
-      memset(& $$, 0, sizeof($$));
-      $$.flags.q.centroid = 1;
-      $$.flags.q.varying = 1;
-   }
    | IN_TOK
    {
       memset(& $$, 0, sizeof($$));
@@ -1473,16 +1493,6 @@ storage_qualifier:
       memset(& $$, 0, sizeof($$));
       $$.flags.q.out = 1;
    }
-   | CENTROID IN_TOK
-   {
-      memset(& $$, 0, sizeof($$));
-      $$.flags.q.centroid = 1; $$.flags.q.in = 1;
-   }
-   | CENTROID OUT_TOK
-   {
-      memset(& $$, 0, sizeof($$));
-      $$.flags.q.centroid = 1; $$.flags.q.out = 1;
-   }
    | UNIFORM
    {
       memset(& $$, 0, sizeof($$));