gigi.h (mark_visited): Declare.

	* gigi.h (mark_visited): Declare.
	* decl.c (gnat_to_gnu_entity): Use mark_visited instead of marking
	only the topmost node of expressions.
	(elaborate_expression_1): Look deeper for read-only variable.
	* trans.c (add_decl_expr): Use mark_visited instead of marking by hand.
	(mark_visited): Move logic to mark_visited_r.  Invoke walk_tree.
	(mark_visited_r): New function.

From-SVN: r135819

gcc/ada/ChangeLog

+2008-05-23  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gigi.h (mark_visited): Declare.
+	* decl.c (gnat_to_gnu_entity): Use mark_visited instead of marking
+	only the topmost node of expressions.
+	(elaborate_expression_1): Look deeper for read-only variable.
+	* trans.c (add_decl_expr): Use mark_visited instead of marking by hand.
+	(mark_visited): Move logic to mark_visited_r.  Invoke walk_tree.
+	(mark_visited_r): New function.
+
 2008-05-23  Vincent Celier  <celier@adacore.com>
 
 	* snames.adb:

gcc/ada/decl.c

@@ -876,7 +876,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 			/* ??? No DECL_EXPR is created so we need to mark
 			   the expression manually lest it is shared.  */
 			if (global_bindings_p ())
-			  TREE_VISITED (gnu_decl) = 1;
+			  mark_visited (&gnu_decl);
 			save_gnu_tree (gnat_entity, gnu_decl, true);
 			saved = true;
 			break;
@@ -2343,7 +2343,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 		  /* ??? create_type_decl is not invoked on the inner types so
 		     the MULT_EXPR node built above will never be marked.  */
-		  TREE_VISITED (TYPE_SIZE_UNIT (gnu_arr_type)) = 1;
+		  mark_visited (&TYPE_SIZE_UNIT (gnu_arr_type));
 		}
 	    }
 
@@ -4379,9 +4379,9 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
 
 		/* ??? The context of gnu_field is not necessarily gnu_type so
 		   the MULT_EXPR node built above may not be marked by the call
-		   to create_type_decl below.  Mark it manually for now.  */
+		   to create_type_decl below.  */
 		if (global_bindings_p ())
-		  TREE_VISITED (DECL_FIELD_OFFSET (gnu_field)) = 1;
+		  mark_visited (&DECL_FIELD_OFFSET (gnu_field));
 		}
 	    }
 
@@ -5295,10 +5295,12 @@ elaborate_expression_1 (Node_Id gnat_expr, Entity_Id gnat_entity,
 			bool need_debug)
 {
   tree gnu_decl = NULL_TREE;
-  /* Strip any conversions to see if the expression is a readonly variable.
-     ??? This really should remain readonly, but we have to think about
+  /* Skip any conversions and simple arithmetics to see if the expression
+     is a read-only variable.
+     ??? This really should remain read-only, but we have to think about
      the typing of the tree here.  */
-  tree gnu_inner_expr = remove_conversions (gnu_expr, true);
+  tree gnu_inner_expr
+    = skip_simple_arithmetic (remove_conversions (gnu_expr, true));
   bool expr_global = Is_Public (gnat_entity) || global_bindings_p ();
   bool expr_variable;
 
@@ -5314,7 +5316,7 @@ elaborate_expression_1 (Node_Id gnat_expr, Entity_Id gnat_entity,
 		       gnu_expr, NULL_TREE);
 
   /* If GNU_EXPR is neither a placeholder nor a constant, nor a variable
-     that is a constant, make a variable that is initialized to contain the
+     that is read-only, make a variable that is initialized to contain the
      bound when the package containing the definition is elaborated.  If
      this entity is defined at top level and a bound or discriminant value
      isn't a constant or a reference to a discriminant, replace the bound

gcc/ada/gigi.h

@@ -102,6 +102,11 @@ extern void set_block_for_group (tree);
    Get SLOC from GNAT_ENTITY.  */
 extern void add_decl_expr (tree gnu_decl, Entity_Id gnat_entity);
 
+/* Mark nodes rooted at *TP with TREE_VISITED and types as having their
+   sized gimplified.  We use this to indicate all variable sizes and
+   positions in global types may not be shared by any subprograms.  */
+extern void mark_visited (tree *);
+
 /* Finalize any From_With_Type incomplete types.  We do this after processing
    our compilation unit and after processing its spec, if this is a body.  */
 extern void finalize_from_with_types (void);

gcc/ada/trans.c

@@ -186,7 +186,6 @@ static void Compilation_Unit_to_gnu (Node_Id);
 static void record_code_position (Node_Id);
 static void insert_code_for (Node_Id);
 static void add_cleanup (tree, Node_Id);
-static tree mark_visited (tree *, int *, void *);
 static tree unshare_save_expr (tree *, int *, void *);
 static void add_stmt_list (List_Id);
 static void push_exception_label_stack (tree *, Entity_Id);
@@ -5102,13 +5101,13 @@ add_decl_expr (tree gnu_decl, Entity_Id gnat_entity)
       /* Mark everything as used to prevent node sharing with subprograms.
 	 Note that walk_tree knows how to deal with TYPE_DECL, but neither
 	 VAR_DECL nor CONST_DECL.  This appears to be somewhat arbitrary.  */
-      walk_tree (&gnu_stmt, mark_visited, NULL, NULL);
+      mark_visited (&gnu_stmt);
       if (TREE_CODE (gnu_decl) == VAR_DECL
 	  || TREE_CODE (gnu_decl) == CONST_DECL)
 	{
-	  walk_tree (&DECL_SIZE (gnu_decl), mark_visited, NULL, NULL);
-	  walk_tree (&DECL_SIZE_UNIT (gnu_decl), mark_visited, NULL, NULL);
-	  walk_tree (&DECL_INITIAL (gnu_decl), mark_visited, NULL, NULL);
+	  mark_visited (&DECL_SIZE (gnu_decl));
+	  mark_visited (&DECL_SIZE_UNIT (gnu_decl));
+	  mark_visited (&DECL_INITIAL (gnu_decl));
 	}
       /* In any case, we have to deal with our own TYPE_ADA_SIZE field.  */
       if (TREE_CODE (gnu_decl) == TYPE_DECL
@@ -5116,7 +5115,7 @@ add_decl_expr (tree gnu_decl, Entity_Id gnat_entity)
 	      || TREE_CODE (type) == UNION_TYPE
 	      || TREE_CODE (type) == QUAL_UNION_TYPE)
 	  && (t = TYPE_ADA_SIZE (type)))
-	walk_tree (&t, mark_visited, NULL, NULL);
+	mark_visited (&t);
     }
   else
     add_stmt_with_node (gnu_stmt, gnat_entity);
@@ -5150,13 +5149,10 @@ add_decl_expr (tree gnu_decl, Entity_Id gnat_entity)
     }
 }
 
-/* Utility function to mark nodes with TREE_VISITED and types as having their
-   sized gimplified.  Called from walk_tree.  We use this to indicate all
-   variable sizes and positions in global types may not be shared by any
-   subprogram.  */
+/* Callback for walk_tree to mark the visited trees rooted at *TP.  */
 
 static tree
-mark_visited (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
+mark_visited_r (tree *tp, int *walk_subtrees, void *data ATTRIBUTE_UNUSED)
 {
   if (TREE_VISITED (*tp))
     *walk_subtrees = 0;
@@ -5186,6 +5182,16 @@ unshare_save_expr (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED,
   return NULL_TREE;
 }
 
+/* Mark nodes rooted at *TP with TREE_VISITED and types as having their
+   sized gimplified.  We use this to indicate all variable sizes and
+   positions in global types may not be shared by any subprogram.  */
+
+void
+mark_visited (tree *tp)
+{
+  walk_tree (tp, mark_visited_r, NULL, NULL);
+}
+
 /* Add GNU_CLEANUP, a cleanup action, to the current code group and
    set its location to that of GNAT_NODE if present.  */