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[PATCH] Fix minimal alignment calculation for user-aligned types (PR63802)
- From: Yury Gribov <y dot gribov at samsung dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: Jakub Jelinek <jakub at redhat dot com>, Marek Polacek <polacek at redhat dot com>, Andrey Ryabinin <a dot ryabinin at samsung dot com>
- Date: Fri, 14 Nov 2014 09:46:14 +0300
- Subject: [PATCH] Fix minimal alignment calculation for user-aligned types (PR63802)
- Authentication-results: sourceware.org; auth=none
Hi all,
This patch fixes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63802 by
only limiting minimal type alignment with BIGGEST_ALIGNMENT for types
with no __attribute__((aligned)).
Bootstrapped and regtested on x64. Ok for trunk?
-Y
>From 7e5d09453dcff22f591162e1b5c5a115b17b0014 Mon Sep 17 00:00:00 2001
From: Yury Gribov <y.gribov@samsung.com>
Date: Thu, 13 Nov 2014 21:29:51 +0300
Subject: [PATCH] 2014-11-14 Yury Gribov <y.gribov@samsung.com>
PR sanitizer/63802
gcc/
* stor-layout.c (min_align_of_type): Respect user alignment
more.
gcc/testsuite/
* c-c++-common/ubsan/pr63802.c: New test.
---
gcc/stor-layout.c | 2 +-
gcc/testsuite/c-c++-common/ubsan/pr63802.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/c-c++-common/ubsan/pr63802.c
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 431b207..db09855 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -2430,9 +2430,9 @@ unsigned int
min_align_of_type (tree type)
{
unsigned int align = TYPE_ALIGN (type);
- align = MIN (align, BIGGEST_ALIGNMENT);
if (!TYPE_USER_ALIGN (type))
{
+ align = MIN (align, BIGGEST_ALIGNMENT);
#ifdef BIGGEST_FIELD_ALIGNMENT
align = MIN (align, BIGGEST_FIELD_ALIGNMENT);
#endif
diff --git a/gcc/testsuite/c-c++-common/ubsan/pr63802.c b/gcc/testsuite/c-c++-common/ubsan/pr63802.c
new file mode 100644
index 0000000..454c098
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/ubsan/pr63802.c
@@ -0,0 +1,23 @@
+/* Limit this to known non-strict alignment targets. */
+/* { dg-do run { target { i?86-*-linux* x86_64-*-linux* } } } */
+/* { dg-options "-fsanitize=alignment" } */
+
+#define __round_mask(x, y) ((__typeof__(x))((y)-1))
+#define round_up(x, y) ((((x)-1) | __round_mask(x, y))+1)
+
+struct test_struct {
+ unsigned long a;
+ int b;
+} __attribute__((__aligned__(64)));
+
+char a[200];
+
+int main ()
+{
+ volatile int x = ((struct test_struct*)(round_up((unsigned long)a, 64) + 16))->b;
+ volatile int y = ((struct test_struct*)(round_up((unsigned long)a, 64) + 15))->b;
+
+ return 0;
+}
+
+/* { dg-output "\.c:18:\[0-9]*: \[^\n\r]*member access within misaligned address 0x\[0-9a-fA-F]* for type 'struct test_struct', which requires 64 byte alignment.*" } */
--
1.7.9.5