Bug 179554 - [bad-code/4.2] sigc++-2.0 based code with -fstrict-aliasing crashes with compiled gcc 4.2
Bug#: 179554 Product:  Gentoo Linux Version: unspecified Platform: All
OS/Version: Linux Status: RESOLVED Severity: normal Priority: P2
Resolution: FIXED Assigned To: toolchain@gentoo.org Reported By: loki_val@gentoo.org
Component: Core system
URL:  http://gcc.gnu.org/PR30252
Summary: [bad-code/4.2] sigc++-2.0 based code with -fstrict-aliasing crashes with compiled gcc 4.2
Keywords:  
Status Whiteboard: 
Opened: 2007-05-23 17:53 0000
Description:   Opened: 2007-05-23 17:53 0000 
This has been reported upstream, see URL in bug description. This may be the
same bug that's mentioned here:
[4.2 regression] miscompilation of sigc++-2.0 based code with -fstrict-aliasing
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30252

Having recompiled my system with the new gcc-4.2.0 and glibc-2.6, I tried to
run rtorrent. It segfaults:
pa@loki ~/session $ rtorrent
Caught Segmentation fault, dumping stack:
0 rtorrent [0x8058ff1]
1 rtorrent [0x806d6d9]
2 [0xffffe420]
3 [0x82e938e]
4 rtorrent [0x805877d]
5 /lib/libc.so.6(__libc_start_main+0xe0) [0xb7a159d0]
6 rtorrent(_ZN7torrent18set_max_open_filesEj+0x89) [0x8051b01]
Aborted

I have, for now, recompiled just rtorrent and libtorrent with gcc-4.1.2, which
works fine. 

Reproducible: Always

Steps to Reproduce:

------- Comment #1 From Timothy Redaelli 2007-05-23 18:48:52 0000 ------- 
Can you try to use -fno-strict-aliasing in CFLAGS and see if it works?

------- Comment #2 From Peter Alfredsen 2007-05-23 20:45:37 0000 ------- 
I just recompiled libtorrent and rtorrent with these parameters:
CFLAGS="-Os -march=athlon-xp -pipe -ggdb3 -fno-strict-aliasing" CXXFLAGS="-Os
-march=athlon-xp -pipe -ggdb3 -fno-strict-aliasing" emerge -1 libtorrent
rtorrent
So far, it seems to work fine.

------- Comment #3 From SpanKY 2007-06-18 04:26:28 0000 ------- 
*** Bug 181124 has been marked as a duplicate of this bug. ***

------- Comment #4 From SpanKY 2007-06-18 04:29:12 0000 ------- 
rtorrent report: http://libtorrent.rakshasa.no/ticket/926

but in reality, a gcc-4.2 bug

------- Comment #5 From Ryan Hill 2007-06-20 00:10:37 0000 ------- 
Created an attachment (id=122558) [details]
41_all_gcc42-PR30252.patch

here's the patch.  this should apply after 40_all_gcc42-PR30052.patch.

------- Comment #6 From Peter Alfredsen 2007-06-21 16:44:37 0000 ------- 
(In reply to comment #5)
> Created an attachment (id=122558) [edit] [details]
> 41_all_gcc42-PR30252.patch
> 
> here's the patch.  this should apply after 40_all_gcc42-PR30052.patch.
> 

I've just applied this to my local gcc-4.2.0 and gcc builds and rtorrent runs.
(I changed the libtorrent and rtorrent ebuilds to not append-flags
fno-strict-aliasing).

------- Comment #7 From Raul Metsma 2007-06-21 18:40:09 0000 ------- 
Built just new gcc with 1.2 patchet and this patch but still inkscape crashes

------- Comment #8 From SpanKY 2007-06-22 01:59:23 0000 ------- 
the fix from upstream has been put into the 1.3 patchset

------- Comment #9 From Raul Metsma 2007-06-23 11:33:10 0000 ------- 
Inkscape is still no good with 1.3 patchet

------- Comment #10 From SpanKY 2007-06-23 14:33:08 0000 ------- 
what exactly did you re-compile ?  rebuilding just inkscape i dont think would
be enough

------- Comment #11 From Raul Metsma 2007-06-23 16:55:10 0000 ------- 
Rebuild gcc-4.2.0 and after that inkscape

------- Comment #12 From SpanKY 2007-06-23 17:03:41 0000 ------- 
which isnt sufficient i dont think ... rebuild all the packages related to
inkscape, first starting with dev-libs/libsigc++