ubsan.c (ubsan_type_descriptor): If varpool_get_node returns NULL for a decl, recreate that decl.

2013-11-27  Marek Polacek  <polacek@redhat.com>

	* ubsan.c (ubsan_type_descriptor): If varpool_get_node returns NULL
	for a decl, recreate that decl.  Save into the hash table VAR_DECLs
	rather than ADDR_EXPRs.
testsuite/
	* c-c++-common/ubsan/undefined-1.c: New test.

From-SVN: r205433

gcc/ChangeLog

+2013-11-27  Marek Polacek  <polacek@redhat.com>
+
+	* ubsan.c (ubsan_type_descriptor): If varpool_get_node returns NULL
+	for a decl, recreate that decl.  Save into the hash table VAR_DECLs
+	rather than ADDR_EXPRs.
+
 2013-11-27  Alexander Ivchenko  <alexander.ivchenko@intel.com>
 
 	* config/ia64/hpux.h (TARGET_LIBC_HAS_FUNCTION): Fix typo.

gcc/testsuite/ChangeLog

+2013-11-27  Marek Polacek  <polacek@redhat.com>
+
+	* c-c++-common/ubsan/undefined-1.c: New test.
+
 2013-11-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/59014

gcc/testsuite/c-c++-common/ubsan/undefined-1.c

+/* { dg-do run } */
+/* { dg-options "-fsanitize=undefined" } */
+/* { dg-skip-if "" { *-*-* } { "-flto" } { "" } } */
+
+int
+foo (int x, int y)
+{
+  const int z = 2;
+  if (z & 1)
+    return x << y;
+  return 0;
+}
+
+int
+bar (int x, int y)
+{
+  return x + y;
+}
+
+int
+main (void)
+{
+  foo (3, 2);
+  bar (12, 42);
+  return 0;
+}

gcc/ubsan.c

@@ -272,8 +272,12 @@ ubsan_type_descriptor (tree type, bool want_pointer_type_p)
   type = TYPE_MAIN_VARIANT (type);
 
   tree decl = decl_for_type_lookup (type);
-  if (decl != NULL_TREE)
-    return decl;
+  /* It is possible that some of the earlier created DECLs were found
+     unused, in that case they weren't emitted and varpool_get_node
+     returns NULL node on them.  But now we really need them.  Thus,
+     renew them here.  */
+  if (decl != NULL_TREE && varpool_get_node (decl))
+    return build_fold_addr_expr (decl);
 
   tree dtype = ubsan_type_descriptor_type ();
   tree type2 = type;
@@ -372,11 +376,10 @@ ubsan_type_descriptor (tree type, bool want_pointer_type_p)
   DECL_INITIAL (decl) = ctor;
   rest_of_decl_compilation (decl, 1, 0);
 
-  /* Save the address of the VAR_DECL into the hash table.  */
-  decl = build_fold_addr_expr (decl);
+  /* Save the VAR_DECL into the hash table.  */
   decl_for_type_insert (type, decl);
 
-  return decl;
+  return build_fold_addr_expr (decl);
 }
 
 /* Create a structure for the ubsan library.  NAME is a name of the new