https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88289
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
E.g. on x86_64 in user-after-scope-5.c I see:
.string "1 48 40 9 values:10"
Partition 0: size 40 align 16
values
Flushing rzbuffer at offset -128 with: f1 f1 f1 f1
Flushing rzbuffer at offset -96 with: f1 f1 00 00
Flushing rzbuffer at offset -64 with: 00 00 00 f3
Flushing rzbuffer at offset -32 with: f3 f3 f3 f3
(wonder why the var is at offset 48 bytes rather than just 32 bytes).\
But on powerpc64 I see:
.string "1 48 40 9 values:10"
Partition 0: size 40 align 8
values
Flushing rzbuffer at offset -128 with: 00 f1 f1 f1
Flushing rzbuffer at offset -96 with: 00 00 00 f1
Flushing rzbuffer at offset -64 with: 00 f3 00 00
Flushing rzbuffer at offset -32 with: 00 f3 f3 f3
There is a clear off-by-one for BIG_ENDIAN, with following patch I get:
--- gcc/asan.c.jj 2018-11-30 19:59:59.675789930 +0100
+++ gcc/asan.c 2018-11-30 23:19:55.336780260 +0100
@@ -1326,7 +1326,7 @@ asan_redzone_buffer::flush_redzone_paylo
for (unsigned i = 0; i < RZ_BUFFER_SIZE; i++)
{
unsigned char v
- = m_shadow_bytes[BYTES_BIG_ENDIAN ? RZ_BUFFER_SIZE - i : i];
+ = m_shadow_bytes[BYTES_BIG_ENDIAN ? RZ_BUFFER_SIZE - i - 1 : i];
val |= (unsigned HOST_WIDE_INT)v << (BITS_PER_UNIT * i);
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "%02x ", v);
Partition 0: size 40 align 8
values
Flushing rzbuffer at offset -128 with: f1 f1 f1 f1
Flushing rzbuffer at offset -96 with: 00 00 f1 f1
Flushing rzbuffer at offset -64 with: f3 00 00 00
Flushing rzbuffer at offset -32 with: f3 f3 f3 f3
Unpoisoning shadow stack for variable: values (40 B)
instead, which looks correct.
