sparc64/119289: commit references a PR
dfilter at FreeBSD.org
Sat Jan 5 15:00:02 PST 2008
The following reply was made to PR sparc64/119289; it has been noted by GNATS.
From: dfilter at FreeBSD.ORG (dfilter service)
To: bug-followup at FreeBSD.org
Subject: Re: sparc64/119289: commit references a PR
Date: Sat, 5 Jan 2008 22:58:57 +0000 (UTC)
marius 2008-01-05 22:58:51 UTC
FreeBSD src repository
Modified files: (Branch: RELENG_7)
On FreeBSD GCC 4.2.x checks for the existence of pthread_cancel() in
order to determine whether a program is running with multithreading
support. This check causes __gthread_active_p() to always return 1
however, regardless of whether the program was actually compiled with
-pthread or not, due to the fact that the FreeBSD libc contains a
pthread_cancel() stub. Fix this by using the __gthread_active_p()
version that GCC uses for Solaris and which actively checks for a
working POSIX threads implementation (if such functions exist) instead
of checking for the mere existence of corresponding functions.
On platforms without TLS support, i.e. on arm and sparc64 due to the
lack of GNU TLS support for these archs in binutils 2.15., the false
positives returned by __gthread_active_p() for non-threaded programs
cause the exception handling implementation GCC uses in this case to
crash. This is because GCC assumes that the POSIX threading functions
actually work when __gthread_active_p() returns 1 while in fact the
corresponding stubs in libc just immediately return.
Given that __gthread_active_p() is also used in a couple of other
places besides exception handling, this bug has great potential to
also cause problems in other areas and on all archs.
This is committed to RELENG_7 directly in order to get a fix into
RELENG_7_0 as soon as possible while allowing to loop the official
fix back into the vendor branch and not taking gthr-posix.h off the
vendor branch in HEAD.
Reviewed by: obrien (plus style fix)
Approved by: re (kensmith)
Revision Changes Path
188.8.131.52.2.1 +7 -4 src/contrib/gcc/gthr-posix.h
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