glsl: Add parser support for GL_ARB_explicit_attrib_location layouts

Only layout(location=#) is supported.  Setting the index requires GLSL
1.30 and GL_ARB_blend_func_extended.

src/glsl/ast.h

@@ -343,9 +343,23 @@ struct ast_type_qualifier {
 	 unsigned origin_upper_left:1;
 	 unsigned pixel_center_integer:1;
 	 /*@}*/
+
+	 /**
+	  * Flag set if GL_ARB_explicit_attrib_location "location" layout
+	  * qualifier is used.
+	  */
+	 unsigned explicit_location:1;
       } q;
       unsigned i;
    } flags;
+
+   /**
+    * Location specified via GL_ARB_explicit_attrib_location layout
+    *
+    * \note
+    * This field is only valid if \c explicit_location is set.
+    */
+   unsigned location;
 };
 
 class ast_struct_specifier : public ast_node {

src/glsl/glsl_lexer.lpp

@@ -218,6 +218,7 @@ void		return VOID_TOK;
 
 layout		{
 		  if ((yyextra->language_version >= 140)
+		      || yyextra->ARB_explicit_attrib_location_enable
 		      || (yyextra->ARB_fragment_coord_conventions_enable)){
 		      return LAYOUT_TOK;
 		   } else {

src/glsl/glsl_parser.ypp

@@ -983,10 +983,19 @@ layout_qualifier_id_list:
 	layout_qualifier_id
 	| layout_qualifier_id_list ',' layout_qualifier_id
 	{
-	   /* FINISHME: Should check for conflicting / duplicate flags here.
-	    */
-	   $$ = $1;
-	   $$.flags.i |= $3.flags.i;
+	   if (($1.flags.i & $3.flags.i) != 0) {
+	      _mesa_glsl_error(& @3, state,
+			       "duplicate layout qualifiers used\n");
+	      YYERROR;
+	   }
+
+	   $$.flags.i = $1.flags.i | $3.flags.i;
+
+	   if ($1.flags.q.explicit_location)
+	      $$.location = $1.location;
+
+	   if ($3.flags.q.explicit_location)
+	      $$.location = $3.location;
 	}
 	;
 
@@ -1020,6 +1029,44 @@ layout_qualifier_id:
 				 "identifier `%s' used\n", $1);
 	   }
 	}
+	| IDENTIFIER '=' INTCONSTANT
+	{
+	   bool got_one = false;
+
+	   memset(& $$, 0, sizeof($$));
+
+	   if (state->ARB_explicit_attrib_location_enable) {
+	      /* FINISHME: Handle 'index' once GL_ARB_blend_func_exteneded and
+	       * FINISHME: GLSL 1.30 (or later) are supported.
+	       */
+	      if (strcmp("location", $1) == 0) {
+		 got_one = true;
+
+		 $$.flags.q.explicit_location = 1;
+
+		 if ($3 >= 0) {
+		    $$.location = $3;
+		 } else {
+		    _mesa_glsl_error(& @3, state,
+				     "invalid location %d specified\n", $3);
+		    YYERROR;
+		 }
+	      }
+	   }
+
+	   /* If the identifier didn't match any known layout identifiers,
+	    * emit an error.
+	    */
+	   if (!got_one) {
+	      _mesa_glsl_error(& @1, state, "unrecognized layout identifier "
+			       "`%s'\n", $1);
+	      YYERROR;
+	   } else if (state->ARB_explicit_attrib_location_warn) {
+	      _mesa_glsl_warning(& @1, state,
+				 "GL_ARB_explicit_attrib_location layout "
+				 "identifier `%s' used\n", $1);
+	   }
+	}
 	;
 
 interpolation_qualifier:

src/glsl/glsl_parser_extras.cpp

@@ -181,6 +181,13 @@ _mesa_glsl_process_extension(const char *name, YYLTYPE *name_locp,
 	 state->ARB_draw_buffers_enable = (ext_mode != extension_disable);
 	 state->ARB_draw_buffers_warn = (ext_mode == extension_warn);
       }
+   } else if (strcmp(name, "GL_ARB_explicit_attrib_location") == 0) {
+      state->ARB_explicit_attrib_location_enable =
+	 (ext_mode != extension_disable);
+      state->ARB_explicit_attrib_location_warn =
+	 (ext_mode == extension_warn);
+
+      unsupported = !state->extensions->ARB_explicit_attrib_location;
    } else if (strcmp(name, "GL_ARB_fragment_coord_conventions") == 0) {
       state->ARB_fragment_coord_conventions_enable =
 	 (ext_mode != extension_disable);

src/glsl/glsl_parser_extras.h

@@ -125,6 +125,8 @@ struct _mesa_glsl_parse_state {
    /*@{*/
    unsigned ARB_draw_buffers_enable:1;
    unsigned ARB_draw_buffers_warn:1;
+   unsigned ARB_explicit_attrib_location_enable:1;
+   unsigned ARB_explicit_attrib_location_warn:1;
    unsigned ARB_fragment_coord_conventions_enable:1;
    unsigned ARB_fragment_coord_conventions_warn:1;
    unsigned ARB_texture_rectangle_enable:1;