1 files changed, 74 insertions, 21 deletions

diff --git a/src/glsl/ast.h b/src/glsl/ast.h
index 44c31b6e62..e5aa5c1b3b 100644
--- a/src/glsl/ast.h
+++ b/src/glsl/ast.h
@@ -33,6 +33,20 @@ struct _mesa_glsl_parse_state;
 
 struct YYLTYPE;
 
+/**
+ * \defgroup AST Abstract syntax tree node definitions
+ *
+ * An abstract syntax tree is generated by the parser.  This is a fairly
+ * direct representation of the gramma derivation for the source program.
+ * No symantic checking is done during the generation of the AST.  Only
+ * syntactic checking is done.  Symantic checking is performed by a later
+ * stage that converts the AST to a more generic intermediate representation.
+ *
+ *@{
+ */
+/**
+ * Base class of all abstract syntax tree nodes
+ */
 class ast_node {
 public:
    /* Callers of this talloc-based new need not call delete. It's
@@ -54,7 +68,14 @@ public:
       talloc_free(table);
    }
 
+   /**
+    * Print an AST node in something approximating the original GLSL code
+    */
    virtual void print(void) const;
+
+   /**
+    * Convert the AST node to the high-level intermediate representation
+    */
    virtual ir_rvalue *hir(exec_list *instructions,
 			  struct _mesa_glsl_parse_state *state);
 
@@ -91,19 +112,29 @@ public:
       this->location.column = locp.first_column;
    }
 
+   /**
+    * Source location of the AST node.
+    */
    struct {
-      unsigned source;
-      unsigned line;
-      unsigned column;
+      unsigned source;    /**< GLSL source number. */
+      unsigned line;      /**< Line number within the source string. */
+      unsigned column;    /**< Column in the line. */
    } location;
 
    exec_node link;
 
 protected:
+   /**
+    * The only constructor is protected so that only derived class objects can
+    * be created.
+    */
    ast_node(void);
 };
 
 
+/**
+ * Operators for AST expression nodes.
+ */
 enum ast_operators {
    ast_assign,
    ast_plus,        /**< Unary + operator. */
@@ -161,6 +192,9 @@ enum ast_operators {
    ast_sequence
 };
 
+/**
+ * Representation of any sort of expression.
+ */
 class ast_expression : public ast_node {
 public:
    ast_expression(int oper, ast_expression *,
@@ -290,23 +324,42 @@ enum {
 };
 
 struct ast_type_qualifier {
-   unsigned invariant:1;
-   unsigned constant:1;
-   unsigned attribute:1;
-   unsigned varying:1;
-   unsigned in:1;
-   unsigned out:1;
-   unsigned centroid:1;
-   unsigned uniform:1;
-   unsigned smooth:1;
-   unsigned flat:1;
-   unsigned noperspective:1;
-
-   /** \name Layout qualifiers for GL_ARB_fragment_coord_conventions */
-   /*@{*/
-   unsigned origin_upper_left:1;
-   unsigned pixel_center_integer:1;
-   /*@}*/
+   union {
+      struct {
+	 unsigned invariant:1;
+	 unsigned constant:1;
+	 unsigned attribute:1;
+	 unsigned varying:1;
+	 unsigned in:1;
+	 unsigned out:1;
+	 unsigned centroid:1;
+	 unsigned uniform:1;
+	 unsigned smooth:1;
+	 unsigned flat:1;
+	 unsigned noperspective:1;
+
+	 /** \name Layout qualifiers for GL_ARB_fragment_coord_conventions */
+	 /*@{*/
+	 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 {
@@ -651,7 +704,7 @@ public:
    ast_function *prototype;
    ast_compound_statement *body;
 };
-
+/*@}*/
 
 extern void
 _mesa_ast_to_hir(exec_list *instructions, struct _mesa_glsl_parse_state *state);