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[PATCH] Do not instrument use-after-scope for vars with large alignment (PR sanitizer/82517).
- From: Martin Liška <mliska at suse dot cz>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Jakub Jelinek <jakub at redhat dot com>, Maxim Ostapenko <m dot ostapenko at samsung dot com>
- Date: Thu, 19 Oct 2017 09:21:47 +0200
- Subject: [PATCH] Do not instrument use-after-scope for vars with large alignment (PR sanitizer/82517).
- Authentication-results: sourceware.org; auth=none
Hi.
As discussed with Jakub, use-after-scope sanitization should not be done for variables that have bigger
alignment than MAX_SUPPORTED_STACK_ALIGNMENT. In this case, we can't put a variable to fixed stack slot.
Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
Ready to be installed?
Martin
gcc/ChangeLog:
2017-10-18 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.
gcc/testsuite/ChangeLog:
2017-10-18 Martin Liska <mliska@suse.cz>
PR sanitizer/82517
* gcc.dg/asan/pr82517.c: New test.
---
gcc/gimplify.c | 5 ++++-
gcc/testsuite/gcc.dg/asan/pr82517.c | 43 +++++++++++++++++++++++++++++++++++++
2 files changed, 47 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/asan/pr82517.c
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index c3fd6ace84e..19411c98fce 100644
--- a/gcc/gimplify.c
+++ b/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)
diff --git a/gcc/testsuite/gcc.dg/asan/pr82517.c b/gcc/testsuite/gcc.dg/asan/pr82517.c
new file mode 100644
index 00000000000..c7743ecb8b1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/asan/pr82517.c
@@ -0,0 +1,43 @@
+/* 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;
+}