re PR middle-end/48269 (Incorrect fortify warning for a packed struct member)

2011-03-24  Richard Guenther  <rguenther@suse.de>

	PR middle-end/48269
	* tree-object-size.c (addr_object_size): Do not double-account
	for MEM_REF offsets.

	* gcc.dg/builtin-object-size-10.c: New testcase.

From-SVN: r171388

gcc/ChangeLog

+2011-03-24  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/48269
+	* tree-object-size.c (addr_object_size): Do not double-account
+	for MEM_REF offsets.
+
 2011-03-24  Diego Novillo  <dnovillo@google.com>
 
 	* lto-opts.c (input_data_block): Move to lto-streamer-in.c.

gcc/testsuite/ChangeLog

 2011-03-24  Richard Guenther  <rguenther@suse.de>
 
+	PR middle-end/48269
+	* gcc.dg/builtin-object-size-10.c: New testcase.
+
+2011-03-24  Richard Guenther  <rguenther@suse.de>
+
 	PR tree-optimization/46562
 	* c-c++-common/pr46562-2.c: New testcase.
 	* c-c++-common/pr46562.c: Likewise.

gcc/testsuite/gcc.dg/builtin-object-size-10.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-objsz-details" } */
+
+typedef struct {
+    char sentinel[4];
+    char data[0];
+} drone_packet;
+typedef struct {
+    char type_str[16];
+    char channel_hop;
+} drone_source_packet;
+drone_packet *
+foo(char *x)
+{
+  drone_packet *dpkt = __builtin_malloc(sizeof(drone_packet)
+					+ sizeof(drone_source_packet));
+  drone_source_packet *spkt = (drone_source_packet *) dpkt->data;
+  __builtin___snprintf_chk (spkt->type_str, 16,
+			    1, __builtin_object_size (spkt->type_str, 1),
+			    "%s", x);
+  return dpkt;
+}
+
+/* { dg-final { scan-tree-dump "maximum object size 21" "objsz" } } */
+/* { dg-final { scan-tree-dump "maximum subobject size 16" "objsz" } } */
+/* { dg-final { cleanup-tree-dump "objsz" } } */

gcc/tree-object-size.c

@@ -348,8 +348,6 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
 	  tree bytes2 = compute_object_offset (TREE_OPERAND (ptr, 0), pt_var);
 	  if (bytes2 != error_mark_node)
 	    {
-	      bytes2 = size_binop (PLUS_EXPR, bytes2,
-				   TREE_OPERAND (pt_var, 1));
 	      if (TREE_CODE (bytes2) == INTEGER_CST
 		  && tree_int_cst_lt (pt_var_size, bytes2))
 		bytes2 = size_zero_node;