| Message ID | ZiqfmJDdwgUM54T7@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | libgcc: Don't use weakrefs for glibc 2.34 | expand |
> Am 25.04.2024 um 20:24 schrieb Jakub Jelinek <jakub@redhat.com>: > > Hi! > > glibc 2.34 and later doesn't have separate libpthread (libpthread.so.0 is a > dummy shared library with just some symbol versions for compatibility, but > all the pthread_* APIs are in libc.so.6). > So, we don't need to do the .weakref dances to check whether a program > has been linked with -lpthread or not, in dynamically linked apps those > will be always true anyway. > In -static linking, this fixes various issues people had when only linking > some parts of libpthread.a and getting weird crashes. A hack for that was > what e.g. some Fedora glibcs used, where libpthread.a was a library > containing just one giant *.o file which had all the normal libpthread.a > *.o files linked with -r together. > > libstdc++-v3 actually does something like this already since r10-10928, > the following patch is meant to fix it even for libgfortran, libobjc and > whatever else uses gthr.h. > > Bootstrapped/regtested on x86_64-linux and i686-linux (with glibc 2.35), ok > for trunk? Ok Richard > 2024-04-25 Jakub Jelinek <jakub@redhat.com> > > * gthr.h (GTHREAD_USE_WEAK): Redefine to 0 for GLIBC 2.34 or later. > > --- libgcc/gthr.h.jj 2024-01-03 12:07:28.623363560 +0100 > +++ libgcc/gthr.h 2024-04-25 12:09:39.708622613 +0200 > @@ -141,6 +141,15 @@ see the files COPYING3 and COPYING.RUNTI > #define GTHREAD_USE_WEAK 0 > #endif > > +#ifdef __GLIBC_PREREQ > +#if __GLIBC_PREREQ(2, 34) > +/* glibc 2.34 and later has all pthread_* APIs inside of libc, > + no need to link separately with -lpthread. */ > +#undef GTHREAD_USE_WEAK > +#define GTHREAD_USE_WEAK 0 > +#endif > +#endif > + > #ifndef GTHREAD_USE_WEAK > #define GTHREAD_USE_WEAK 1 > #endif > > Jakub >
On Thu, 25 Apr 2024, Jakub Jelinek wrote: > Hi! > > glibc 2.34 and later doesn't have separate libpthread (libpthread.so.0 is a > dummy shared library with just some symbol versions for compatibility, but > all the pthread_* APIs are in libc.so.6). I suspect this has caused link failures in the glibc testsuite for Hurd, which still has separate libpthread. https://sourceware.org/pipermail/libc-testresults/2024q2/012556.html
--- libgcc/gthr.h.jj 2024-01-03 12:07:28.623363560 +0100 +++ libgcc/gthr.h 2024-04-25 12:09:39.708622613 +0200 @@ -141,6 +141,15 @@ see the files COPYING3 and COPYING.RUNTI #define GTHREAD_USE_WEAK 0 #endif +#ifdef __GLIBC_PREREQ +#if __GLIBC_PREREQ(2, 34) +/* glibc 2.34 and later has all pthread_* APIs inside of libc, + no need to link separately with -lpthread. */ +#undef GTHREAD_USE_WEAK +#define GTHREAD_USE_WEAK 0 +#endif +#endif + #ifndef GTHREAD_USE_WEAK #define GTHREAD_USE_WEAK 1 #endif