On 20/03/2025 14:31, Alfie Richards wrote:
Hello,
This is a cherry pick of 20385cb92cbd4a1934661ab97a162c1e25935836 which didn't
apply cleanly
so needed a very minor edit to for it to apply for GCC 12 and 13.
Regtested and bootstrapped for gcc-13 on aarch64-linux-gnu.
This applies cleanly to gcc-12 but there is a regression for
`c-c++-common/hwasan/large-aligned-1.c`.
The output of execution was
```
==2242916==ERROR: HWAddressSanitizer: tag-mismatch on address 0xfffffffff680 at
pc 0xfffff780e08c
READ of size 4 at 0xfffffffff680 tags: 02/01(00) (ptr/mem) in thread T0
#0 0xfffff780e08c in SigTrap<2>
../../../../src/libsanitizer/hwasan/hwasan_checks.h:28
```
and has changed to
```
==2242927==ERROR: HWAddressSanitizer: tag-mismatch on address 0xfffffffff690 at
pc 0xfffff780e08c
READ of size 4 at 0xfffffffff690 tags: 02/00 (ptr/mem) in thread T0
#0 0xfffff780e08c in SigTrap<2>
../../../../src/libsanitizer/hwasan/hwasan_checks.h:28
```
Note the difference in the tags.
Does anyone with experience of HWAddressSanitizer know what caused this and if
it's an issue?
Yeah, I ran into this too in the past when testing GCC 12 backports.
I think those hwasan tests are flaky due to the dg-output checks being
overly strict. Martin Liska pushed a fix to GCC 13 to relax them
(r13-100-g3771486daa1e904ceae6f3e135b28e58af33849). I think that patch
needs backporting to the GCC 12 branch, which I requested here:
https://gcc.gnu.org/pipermail/gcc-patches/2024-February/645278.html but
that backport request was never ACKed. I still think we should backport
it.
Alex
Ah fantastic, yeah that looks great, thank you for passing it on.
That makes sense then why I didn't see the same regression on GCC-13.
I've applied this and the regression does then go away, so if possible I
would like to commit both?
Alfie
Kind regards,
Alfie Richards
Andrew Carlotti (1):
aarch64: Use PAUTH instead of V8_3A in some places
gcc/config/aarch64/aarch64.cc | 6 +++---
gcc/config/aarch64/aarch64.md | 8 ++++----
2 files changed, 7 insertions(+), 7 deletions(-)
--
2.34.1
