re PR c/48985 (bogus buffer overflow warning and abort on static flexible array member)

2011-05-19  Richard Guenther  <rguenther@suse.de>

	PR middle-end/48985
	* tree-object-size.c (addr_object_size): If the pointed-to
	variable is a decl use DECL_SIZE_UNIT instead of TYPE_SIZE_UNIT.

	* gcc.dg/builtin-object-size-11.c: New testcase.

From-SVN: r173901

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a653ae8442f22bde80efa7315098e29c1e0fd63a..b03cc9bc4af7023df85c20333920e0edaef02101 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2011-05-19  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/48985
+       * tree-object-size.c (addr_object_size): If the pointed-to
+       variable is a decl use DECL_SIZE_UNIT instead of TYPE_SIZE_UNIT.
+
 2011-05-19  Richard Guenther  <rguenther@suse.de>
 
        * gimple.c (gimple_types_compatible_p_1): Compare names of

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index f9defe50594197f1bc7a70a36efbc6bec407ffbe..242a33b0283243daa0c4e130502535d01443a6b8 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2011-05-19  Richard Guenther  <rguenther@suse.de>
+
+       PR middle-end/48985
+       * gcc.dg/builtin-object-size-11.c: New testcase.
+
 2011-05-19  Tom de Vries  <tom@codesourcery.com>
 
        PR target/45098

diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-11.c b/gcc/testsuite/gcc.dg/builtin-object-size-11.c
new file mode 100644 (file)
index 0000000..427b94d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/builtin-object-size-11.c
@@ -0,0 +1,20 @@
+/* PR48985 */
+/* { dg-do run } */
+
+extern void abort (void);
+
+struct s {
+    int i;
+    char c[];
+} s = { 1, "01234" };
+
+__SIZE_TYPE__ f (void) { return __builtin_object_size (&s.c, 0); }
+
+int
+main()
+{
+  if (f() != sizeof ("01234"))
+    abort ();
+
+  return 0;
+}

diff --git a/gcc/tree-object-size.c b/gcc/tree-object-size.c
index 043b445bf2e5e509e934cff0f76b4267d1bd3cbd..41118d25b2ebb5a4f0e126dd55e493826f59d9d1 100644 (file)
--- a/gcc/tree-object-size.c
+++ b/gcc/tree-object-size.c
@@ -204,6 +204,12 @@ addr_object_size (struct object_size_info *osi, const_tree ptr,
       if (sz != unknown[object_size_type] && sz < offset_limit)
        pt_var_size = size_int (sz);
     }
+  else if (pt_var
+          && DECL_P (pt_var)
+          && host_integerp (DECL_SIZE_UNIT (pt_var), 1)
+          && (unsigned HOST_WIDE_INT)
+               tree_low_cst (DECL_SIZE_UNIT (pt_var), 1) < offset_limit)
+    pt_var_size = DECL_SIZE_UNIT (pt_var);
   else if (pt_var
           && (SSA_VAR_P (pt_var) || TREE_CODE (pt_var) == STRING_CST)
           && TYPE_SIZE_UNIT (TREE_TYPE (pt_var))