Do not instrument use-after-scope for vars with large alignment (PR sanitizer/82517).

2017-10-19  Martin Liska  <mliska@suse.cz>

	PR sanitizer/82517
	* gimplify.c (gimplify_decl_expr): Do not instrument variables
	that have a large alignment.
	(gimplify_target_expr): Likewise.
2017-10-19  Martin Liska  <mliska@suse.cz>

	PR sanitizer/82517
	* gcc.dg/asan/pr82517.c: New test.

From-SVN: r253879

gcc/ChangeLog

+2017-10-19  Martin Liska  <mliska@suse.cz>
+
+	PR sanitizer/82517
+	* gimplify.c (gimplify_decl_expr): Do not instrument variables
+	that have a large alignment.
+	(gimplify_target_expr): Likewise.
+
 2017-10-18  Segher Boessenkool  <segher@kernel.crashing.org>
 
 	PR rtl-optimization/82602

gcc/gimplify.c

@@ -1656,6 +1656,7 @@ gimplify_decl_expr (tree *stmt_p, gimple_seq *seq_p)
 	  && TREE_ADDRESSABLE (decl)
 	  && !TREE_STATIC (decl)
 	  && !DECL_HAS_VALUE_EXPR_P (decl)
+	  && DECL_ALIGN (decl) <= MAX_SUPPORTED_STACK_ALIGNMENT
 	  && dbg_cnt (asan_use_after_scope))
 	{
 	  asan_poisoned_variables->add (decl);
@@ -6505,7 +6506,9 @@ gimplify_target_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
 	      clobber = build2 (MODIFY_EXPR, TREE_TYPE (temp), temp, clobber);
 	      gimple_push_cleanup (temp, clobber, false, pre_p, true);
 	    }
-	  if (asan_poisoned_variables && dbg_cnt (asan_use_after_scope))
+	  if (asan_poisoned_variables
+	      && DECL_ALIGN (temp) <= MAX_SUPPORTED_STACK_ALIGNMENT
+	      && dbg_cnt (asan_use_after_scope))
 	    {
 	      tree asan_cleanup = build_asan_poison_call_expr (temp);
 	      if (asan_cleanup)

gcc/testsuite/ChangeLog

+2017-10-19  Martin Liska  <mliska@suse.cz>
+
+	PR sanitizer/82517
+	* gcc.dg/asan/pr82517.c: New test.
+
 2017-10-19  Jakub Jelinek  <jakub@redhat.com>
 
 	PR fortran/82568

gcc/testsuite/gcc.dg/asan/pr82517.c

+/* PR sanitizer/82517.  */
+
+static int *pp;
+
+void
+baz ()
+{
+  return;
+}
+
+void
+bar (int *p)
+{
+  *p = 1;
+}
+
+void
+foo (int a)
+{
+  if (a == 2)
+    {
+    lab:
+      baz ();
+      return;
+    }
+  if (a > 1)
+    {
+      int x __attribute__ ((aligned (256)));
+      pp = &x;
+      bar (&x);
+      if (!x)
+	goto lab;
+    }
+}
+
+int
+main (int argc, char **argv)
+{
+  foo (4);
+  foo (3);
+
+  return 0;
+}