Begin processing #extension directive

Nowhere near complete.  It just parses correctly at this point.

glsl_parser.ypp

@@ -190,13 +190,13 @@ translation_unit:
 	{
 	   _mesa_glsl_initialize_types(state);
 	}
-	external_declaration_list
+	extension_statement_list external_declaration_list
 	|
 	{
 	   state->language_version = 110;
 	   _mesa_glsl_initialize_types(state);
 	}
-	external_declaration_list
+	extension_statement_list external_declaration_list
 	;
 
 version_statement:
@@ -217,6 +217,20 @@ version_statement:
 	}
 	;
 
+extension_statement_list:
+
+	| extension_statement_list extension_statement
+	;
+
+extension_statement:
+	EXTENSION IDENTIFIER COLON IDENTIFIER EOL
+	{
+	   if (!_mesa_glsl_process_extension($2, & @2, $4, & @4, state)) {
+	      YYERROR;
+	   }
+	}
+	;
+
 external_declaration_list:
 	external_declaration
 	{

glsl_parser_extras.cpp

@@ -71,6 +71,53 @@ _mesa_glsl_error(YYLTYPE *locp, _mesa_glsl_parse_state *state,
 }
 
 
+bool
+_mesa_glsl_process_extension(const char *name, YYLTYPE *name_locp,
+			     const char *behavior, YYLTYPE *behavior_locp,
+			     _mesa_glsl_parse_state *state)
+{
+   enum {
+      extension_disable,
+      extension_enable,
+      extension_require,
+      extension_warn
+   } ext_mode;
+   bool error = false;
+
+   if (strcmp(behavior, "warn") == 0) {
+      ext_mode = extension_warn;
+   } else if (strcmp(behavior, "require") == 0) {
+      ext_mode = extension_require;
+   } else if (strcmp(behavior, "enable") == 0) {
+      ext_mode = extension_enable;
+   } else if (strcmp(behavior, "disable") == 0) {
+      ext_mode = extension_disable;
+   } else {
+      _mesa_glsl_error(behavior_locp, state,
+		       "Unknown extension behavior `%s'",
+		       behavior);
+      return false;
+   }
+
+   if (strcmp(name, "all") == 0) {
+      if ((ext_mode == extension_enable) || (ext_mode == extension_require)) {
+	 _mesa_glsl_error(name_locp, state, "Cannot %s all extensions",
+			  (ext_mode == extension_enable)
+			  ? "enable" : "require");
+	 return false;
+      }
+   } else {
+      if (ext_mode == extension_require) {
+	 _mesa_glsl_error(name_locp, state, "Unknown extension `%s'",
+			  name);
+	 return false;
+      }
+   }
+
+   return true;
+}
+
+
 ast_node::~ast_node()
 {
    /* empty */

glsl_parser_extras.h

@@ -85,6 +85,18 @@ extern int _mesa_glsl_lex(union YYSTYPE *yylval, YYLTYPE *yylloc,
 
 extern int _mesa_glsl_parse(struct _mesa_glsl_parse_state *);
 
+/**
+ * Process elements of the #extension directive
+ *
+ * \return
+ * If \c name and \c behavior are valid, \c true is returned.  Otherwise
+ * \c false is returned.
+ */
+extern bool _mesa_glsl_process_extension(const char *name, YYLTYPE *name_locp,
+					 const char *behavior,
+					 YYLTYPE *behavior_locp,
+					 _mesa_glsl_parse_state *state);
+
 /**
  * Get the textual name of the specified shader target
  */