re PR c++/15471 (Incorrect member pointer offsets in anonymous structs/unions)

	PR c++/15471
	* typeck.c (unary_complex_lvalue): Use context_for_name_lookup
	when determining the scope to use for a pointer to member.
	(lookup_anon_field): Give it external linkage.
	* cp-tree.h (lookup_anon_field): Declare it.
	* expr.c (cplus_expand_constant): Use it.

From-SVN: r82401

gcc/cp/ChangeLog

@@ -16,6 +16,9 @@
 	PR c++/15471
 	* typeck.c (unary_complex_lvalue): Use context_for_name_lookup
 	when determining the scope to use for a pointer to member.
+	(lookup_anon_field): Give it external linkage.
+	* cp-tree.h (lookup_anon_field): Declare it.
+	* expr.c (cplus_expand_constant): Use it.
 
 2004-05-28  Mark Mitchell  <mark@codesourcery.com>
 

gcc/cp/cp-tree.h

@@ -4243,6 +4243,7 @@ extern tree build_ptrmemfunc_access_expr       (tree, tree);
 extern tree build_address                       (tree);
 extern tree build_nop                           (tree, tree);
 extern tree non_reference                       (tree);
+extern tree lookup_anon_field                   (tree, tree);
 
 /* in typeck2.c */
 extern void require_complete_eh_spec_types	(tree, tree);

gcc/cp/expr.c

@@ -51,8 +51,21 @@ cplus_expand_constant (tree cst)
 	member = PTRMEM_CST_MEMBER (cst);
 
 	if (TREE_CODE (member) == FIELD_DECL) 
-	  /* Find the offset for the field.  */
-	  cst = fold (build_nop (type, byte_position (member)));
+	  {
+	    /* Find the offset for the field.  */
+	    cst = byte_position (member);
+	    while (!same_type_p (DECL_CONTEXT (member),
+				 TYPE_PTRMEM_CLASS_TYPE (type)))
+	      {
+		/* The MEMBER must have been nestled within an
+		   anonymous aggregate contained in TYPE.  Find the
+		   anonymous aggregate.  */
+		member = lookup_anon_field (TYPE_PTRMEM_CLASS_TYPE (type),
+					    DECL_CONTEXT (member));
+		cst = size_binop (PLUS_EXPR, cst, byte_position (member));
+	      }
+	    cst = fold (build_nop (type, cst));
+	  }
 	else
 	  {
 	    tree delta;

gcc/cp/typeck.c

@@ -54,7 +54,6 @@ static int comp_ptr_ttypes_const (tree, tree);
 static bool comp_except_types (tree, tree, bool);
 static bool comp_array_types (tree, tree, bool);
 static tree common_base_type (tree, tree);
-static tree lookup_anon_field (tree, tree);
 static tree pointer_diff (tree, tree, tree);
 static tree get_delta_difference (tree, tree, int);
 static void casts_away_constness_r (tree *, tree *);
@@ -1517,7 +1516,7 @@ rationalize_conditional_expr (enum tree_code code, tree t)
    anonymous unions can nest, we must also search all anonymous unions
    that are directly reachable.  */
 
-static tree
+tree
 lookup_anon_field (tree t, tree type)
 {
   tree field;