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Ping[5]: [PATCH v4] Destructor support for C++11 thread_localvariables
- From: Siddhesh Poyarekar <siddhesh at redhat dot com>
- To: libc-alpha at sourceware dot org
- Cc: Jakub Jelinek <jakub at redhat dot com>, Jason Merrill <jason at redhat dot com>, Roland McGrath <roland at hack dot frob dot com>
- Date: Mon, 14 Jan 2013 20:56:24 +0530
- Subject: Ping[5]: [PATCH v4] Destructor support for C++11 thread_localvariables
- References: <20121017184033.109bcd89@spoyarek><20121029085207.21957cd2@spoyarek><20121029063837.GH1752@tucnak.redhat.com><20121030193603.3993aa3c@spoyarek><20121030200754.3680c8ba@spoyarek><20121105163606.0b126f51@spoyarek><20121115140548.31c9aa9a@spoyarek><20121214100120.GA8938@spoyarek.pnq.redhat.com><20130108095627.GB27464@spoyarek.pnq.redhat.com>
Ping!
On Tue, Jan 08, 2013 at 03:26:27PM +0530, Siddhesh Poyarekar wrote:
> Ping!
>
> Siddhesh
>
> On Fri, Dec 14, 2012 at 03:31:21PM +0530, Siddhesh Poyarekar wrote:
> > On Thu, Nov 15, 2012 at 02:05:48PM +0530, Siddhesh Poyarekar wrote:
> > > > http://sourceware.org/ml/libc-alpha/2012-10/msg00858.html
> > > >
> >
> > Hi,
> >
> > I've updated this patch for 2.18 along with fixes for a few problems I
> > saw now. I noticed that this requirement has been added to the
> > projects list on the wiki as well:
> >
> > http://sourceware.org/glibc/wiki/Development_Todo/Generic
> >
> > To summarize, this patch adds destructor support for the C++11
> > variables of the thread_local scope. it adds a new function
> > __cxa_thread_atexit_impl, that libstdc++ calls to register destructors
> > for the thread_local objects it constructs. The destructors will then
> > be called at either thread exit or program exit. This patch also
> > ensures that DSOs defining thread_local objects are not unloaded till
> > destructors of all those objects are called. The previous thread is
> > here:
> >
> > http://sourceware.org/ml/libc-alpha/2012-10/msg00289.html
> >
> > Siddhesh
> >
> >
> > ChangeLog:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * Versions.def: Add GLIBC_2.18.
> > * include/link.h (struct link_map): New member l_tls_dtor_count.
> > * include/stdlib.h (__cxa_thread_atexit_impl): Declare.
> > (__call_tls_dtors): Likewise.
> > * sysdeps/unix/sysv/linux/i386/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> > * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/powerpc/powerpc64/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/s390/s390-32/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/s390/s390-64/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/sh/nptl/libc.abilist: Likewise.
> > * sysdeps/unix/sysv/linux/sparc/sparc32/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/sparc/sparc64/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/x86_64/64/nptl/libc.abilist: Likewise.
> > * sysdeps/unix/sysv/linux/x86_64/x32/nptl/libc.abilist:
> > Likewise.
> > * stdlib/Makefile (routines): Add __cxa_thread_atexit_impl.
> > (tests): Add test case tst-tls-atexit.
> > (modules-names): Add shared library for tst-tls-atexit.
> > * stdlib/Versions (GLIBC_2.17): Add __cxa_thread_atexit_impl.
> > (GLIBC_PRIVATE): Add __call_tls_dtors.
> > * stdlib/cxa_thread_atexit_impl.c: New file with helper function
> > for libstdc++.
> > * stdlib/exit.c (__run_exit_handlers): Call __call_tls_dtors.
> > * stdlib/tst-tls-atexit.c: New test case.
> > * stdlib/tst-tls-atexit-lib.c: New test case.
> >
> > ports/ChangeLog.alpha:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/alpha/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> >
> > ports/ChangeLog.arm:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/arm/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> >
> > ports/ChangeLog.ia64:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/ia64/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> >
> > ports/ChangeLog.m68k:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> > * sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist:
> > Likewise.
> >
> > ports/ChangeLog.mips:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/mips/mips32/nptl/libc.abilist: Add
> > __cxa_thread_atexit_impl.
> > * sysdeps/unix/sysv/linux/mips/mips64/n32/nptl/libc.abilist:
> > Likewise.
> > * sysdeps/unix/sysv/linux/mips/mips64/n64/nptl/libc.abilist:
> > Likewise.
> >
> > ports/ChangeLog.powerpc:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist:
> > Add __cxa_thread_atexit_impl.
> > * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/nptl/libc.abilist:
> > Likewise.
> >
> > ports/ChangeLog.tile:
> >
> > 2012-12-14 Siddhesh Poyarekar <siddhesh@redhat.com>
> >
> > * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/nptl/libc.abilist:
> > Add __cxa_thread_atexit_impl.
> > * sysdeps/unix/sysv/linux/tile/tilepro/nptl/libc.abilist:
> > Likewise.
> >
> > diff --git a/Versions.def b/Versions.def
> > index 3c9e0ae..8651992 100644
> > --- a/Versions.def
> > +++ b/Versions.def
> > @@ -34,6 +34,7 @@ libc {
> > GLIBC_2.15
> > GLIBC_2.16
> > GLIBC_2.17
> > + GLIBC_2.18
> > HURD_CTHREADS_0.3
> > %ifdef EXPORT_UNWIND_FIND_FDE
> > GCC_3.0
> > diff --git a/include/link.h b/include/link.h
> > index d759064..69a3465 100644
> > --- a/include/link.h
> > +++ b/include/link.h
> > @@ -301,6 +301,9 @@ struct link_map
> > /* Index of the module in the dtv array. */
> > size_t l_tls_modid;
> >
> > + /* Number of thread_local objects constructed by this DSO. */
> > + size_t l_tls_dtor_count;
> > +
> > /* Information used to change permission after the relocations are
> > done. */
> > ElfW(Addr) l_relro_addr;
> > diff --git a/include/stdlib.h b/include/stdlib.h
> > index d45b2f0..4387394 100644
> > --- a/include/stdlib.h
> > +++ b/include/stdlib.h
> > @@ -99,6 +99,10 @@ extern int __cxa_atexit (void (*func) (void *), void *arg, void *d);
> > extern int __cxa_atexit_internal (void (*func) (void *), void *arg, void *d)
> > attribute_hidden;
> >
> > +extern int __cxa_thread_atexit_impl (void (*func) (void *), void *arg,
> > + void *d);
> > +extern void __call_tls_dtors (void);
> > +
> > extern void __cxa_finalize (void *d);
> >
> > extern int __posix_memalign (void **memptr, size_t alignment, size_t size);
> > diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> > index 197dfa7..34c0d30 100644
> > --- a/nptl/pthread_create.c
> > +++ b/nptl/pthread_create.c
> > @@ -311,6 +311,9 @@ start_thread (void *arg)
> > #endif
> > }
> >
> > + /* Call destructors for the thread_local TLS variables. */
> > + __call_tls_dtors ();
> > +
> > /* Run the destructor for the thread-local data. */
> > __nptl_deallocate_tsd ();
> >
> > diff --git a/ports/sysdeps/unix/sysv/linux/alpha/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/alpha/nptl/libc.abilist
> > index 1d0cc7e..980e088 100644
> > --- a/ports/sysdeps/unix/sysv/linux/alpha/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/alpha/nptl/libc.abilist
> > @@ -1819,6 +1819,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/ports/sysdeps/unix/sysv/linux/arm/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/arm/nptl/libc.abilist
> > index ceab6b2..ce45208 100644
> > --- a/ports/sysdeps/unix/sysv/linux/arm/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/arm/nptl/libc.abilist
> > @@ -86,6 +86,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.4
> > GLIBC_2.4 A
> > _Exit F
> > diff --git a/ports/sysdeps/unix/sysv/linux/ia64/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/ia64/nptl/libc.abilist
> > index b3510fe..067552d 100644
> > --- a/ports/sysdeps/unix/sysv/linux/ia64/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/ia64/nptl/libc.abilist
> > @@ -86,6 +86,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/ports/sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist
> > index 3c40379..f06cc8e 100644
> > --- a/ports/sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/m68k/coldfire/nptl/libc.abilist
> > @@ -87,6 +87,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.4
> > GLIBC_2.4 A
> > _Exit F
> > diff --git a/ports/sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist
> > index f998b1b..9010ea7 100644
> > --- a/ports/sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/m68k/m680x0/nptl/libc.abilist
> > @@ -1775,6 +1775,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/ports/sysdeps/unix/sysv/linux/mips/mips32/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/mips/mips32/nptl/libc.abilist
> > index 7378869..f8cefd1 100644
> > --- a/ports/sysdeps/unix/sysv/linux/mips/mips32/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/mips/mips32/nptl/libc.abilist
> > @@ -2250,3 +2250,6 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > diff --git a/ports/sysdeps/unix/sysv/linux/mips/mips64/n32/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/mips/mips64/n32/nptl/libc.abilist
> > index df2e637..9dbbd97 100644
> > --- a/ports/sysdeps/unix/sysv/linux/mips/mips64/n32/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/mips/mips64/n32/nptl/libc.abilist
> > @@ -1398,6 +1398,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/ports/sysdeps/unix/sysv/linux/mips/mips64/n64/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/mips/mips64/n64/nptl/libc.abilist
> > index 22b3068..c7e46aa 100644
> > --- a/ports/sysdeps/unix/sysv/linux/mips/mips64/n64/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/mips/mips64/n64/nptl/libc.abilist
> > @@ -1396,6 +1396,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/ports/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist
> > index 0efc6b5..9b6d663 100644
> > --- a/ports/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/libc.abilist
> > @@ -1781,6 +1781,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/nptl/libc.abilist
> > index d79b2df..caf74b8 100644
> > --- a/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/nptl/libc.abilist
> > @@ -2088,3 +2088,6 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > diff --git a/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/nptl/libc.abilist
> > index f617405..68d975b 100644
> > --- a/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/nptl/libc.abilist
> > @@ -2088,3 +2088,6 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > diff --git a/ports/sysdeps/unix/sysv/linux/tile/tilepro/nptl/libc.abilist b/ports/sysdeps/unix/sysv/linux/tile/tilepro/nptl/libc.abilist
> > index d79b2df..caf74b8 100644
> > --- a/ports/sysdeps/unix/sysv/linux/tile/tilepro/nptl/libc.abilist
> > +++ b/ports/sysdeps/unix/sysv/linux/tile/tilepro/nptl/libc.abilist
> > @@ -2088,3 +2088,6 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > diff --git a/stdlib/Makefile b/stdlib/Makefile
> > index 5e99d7f..20287da 100644
> > --- a/stdlib/Makefile
> > +++ b/stdlib/Makefile
> > @@ -33,7 +33,7 @@ routines := \
> > bsearch qsort msort \
> > getenv putenv setenv secure-getenv \
> > exit on_exit atexit cxa_atexit cxa_finalize old_atexit \
> > - quick_exit at_quick_exit cxa_at_quick_exit \
> > + quick_exit at_quick_exit cxa_at_quick_exit cxa_thread_atexit_impl \
> > abs labs llabs \
> > div ldiv lldiv \
> > mblen mbstowcs mbtowc wcstombs wctomb \
> > @@ -70,9 +70,11 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
> > tst-makecontext2 tst-strtod6 tst-unsetenv1 \
> > tst-makecontext3 bug-getcontext bug-fmtmsg1 \
> > tst-secure-getenv tst-strtod-overflow tst-strtod-round \
> > - tst-tininess tst-strtod-underflow
> > + tst-tininess tst-strtod-underflow tst-tls-atexit
> > tests-static := tst-secure-getenv
> >
> > +modules-names = tst-tls-atexit-lib
> > +
> > include ../Makeconfig
> >
> > ifeq ($(build-shared),yes)
> > @@ -154,3 +156,9 @@ $(objpfx)bug-getcontext: $(link-libm)
> > $(objpfx)tst-strtod-round: $(link-libm)
> > $(objpfx)tst-tininess: $(link-libm)
> > $(objpfx)tst-strtod-underflow: $(link-libm)
> > +
> > +tst-tls-atexit-lib.so-no-z-defs = yes
> > +
> > +LDFLAGS-tst-tls-atexit = $(common-objpfx)nptl/libpthread.so \
> > + $(common-objpfx)dlfcn/libdl.so
> > +$(objpfx)tst-tls-atexit.out: $(objpfx)tst-tls-atexit-lib.so
> > diff --git a/stdlib/Versions b/stdlib/Versions
> > index 250bd5f..f1777df 100644
> > --- a/stdlib/Versions
> > +++ b/stdlib/Versions
> > @@ -106,6 +106,9 @@ libc {
> > GLIBC_2.17 {
> > secure_getenv;
> > }
> > + GLIBC_2.18 {
> > + __cxa_thread_atexit_impl;
> > + }
> > GLIBC_PRIVATE {
> > # functions which have an additional interface since they are
> > # are cancelable.
> > @@ -114,5 +117,6 @@ libc {
> > __abort_msg;
> > # Used from other libraries
> > __libc_secure_getenv;
> > + __call_tls_dtors;
> > }
> > }
> > diff --git a/stdlib/cxa_thread_atexit_impl.c b/stdlib/cxa_thread_atexit_impl.c
> > new file mode 100644
> > index 0000000..4f03126
> > --- /dev/null
> > +++ b/stdlib/cxa_thread_atexit_impl.c
> > @@ -0,0 +1,108 @@
> > +/* Register destructors for C++ TLS variables declared with thread_local.
> > + Copyright (C) 2012 Free Software Foundation, Inc.
> > + This file is part of the GNU C Library.
> > +
> > + The GNU C Library is free software; you can redistribute it and/or
> > + modify it under the terms of the GNU Lesser General Public
> > + License as published by the Free Software Foundation; either
> > + version 2.1 of the License, or (at your option) any later version.
> > +
> > + The GNU C Library is distributed in the hope that it will be useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + Lesser General Public License for more details.
> > +
> > + You should have received a copy of the GNU Lesser General Public
> > + License along with the GNU C Library; if not, see
> > + <http://www.gnu.org/licenses/>. */
> > +
> > +#include <stdlib.h>
> > +#include <ldsodefs.h>
> > +
> > +typedef void (*dtor_func) (void *);
> > +
> > +struct dtor_list
> > +{
> > + dtor_func func;
> > + void *obj;
> > + struct link_map *map;
> > + struct dtor_list *next;
> > +};
> > +
> > +static __thread struct dtor_list *tls_dtor_list;
> > +static __thread void *dso_handle_cache;
> > +static __thread struct link_map *lm_cache;
> > +
> > +/* Register a destructor for TLS variables declared with the 'thread_local'
> > + keyword. This function is only called from code generated by the C++
> > + compiler. */
> > +int
> > +__cxa_thread_atexit_impl (dtor_func func, void *obj, void *dso_handle)
> > +{
> > + /* Prepend. */
> > + struct dtor_list *new = calloc (1, sizeof (struct dtor_list));
> > + new->func = func;
> > + new->obj = obj;
> > + new->next = tls_dtor_list;
> > + tls_dtor_list = new;
> > +
> > + /* See if we already encountered the DSO. */
> > + __rtld_lock_lock_recursive (GL(dl_load_lock));
> > +
> > + if (__builtin_expect (dso_handle_cache != dso_handle, 0))
> > + {
> > + ElfW(Addr) caller = (ElfW(Addr)) dso_handle;
> > +
> > + /* If the address is not recognized the call comes from the main
> > + program (we hope). */
> > + lm_cache = GL(dl_ns)[LM_ID_BASE]._ns_loaded;
> > +
> > + /* Find the highest-addressed object that DSO_HANDLE is not below. */
> > + for (Lmid_t ns = 0; ns < GL(dl_nns); ++ns)
> > + for (struct link_map *l = GL(dl_ns)[ns]._ns_loaded; l != NULL;
> > + l = l->l_next)
> > + if (caller >= l->l_map_start && caller < l->l_map_end
> > + && (l->l_contiguous || _dl_addr_inside_object (l, caller)))
> > + {
> > + lm_cache = l;
> > + break;
> > + }
> > +
> > + }
> > + /* A destructor could result in a thread_local construction and the former
> > + could have cleared the flag. */
> > + if (lm_cache->l_type == lt_loaded && lm_cache->l_tls_dtor_count == 0)
> > + lm_cache->l_flags_1 |= DF_1_NODELETE;
> > +
> > + new->map = lm_cache;
> > + new->map->l_tls_dtor_count++;
> > +
> > + __rtld_lock_unlock_recursive (GL(dl_load_lock));
> > +
> > + return 0;
> > +}
> > +
> > +/* Call the destructors. This is called either when a thread returns from the
> > + initial function or when the process exits via the exit(3) function. */
> > +void
> > +__call_tls_dtors (void)
> > +{
> > + while (tls_dtor_list)
> > + {
> > + struct dtor_list *cur = tls_dtor_list;
> > + tls_dtor_list = tls_dtor_list->next;
> > +
> > + cur->func (cur->obj);
> > +
> > + __rtld_lock_lock_recursive (GL(dl_load_lock));
> > +
> > + /* Allow DSO unload if count drops to zero. */
> > + cur->map->l_tls_dtor_count--;
> > + if (cur->map->l_tls_dtor_count == 0 && cur->map->l_type == lt_loaded)
> > + cur->map->l_flags_1 &= ~DF_1_NODELETE;
> > +
> > + __rtld_lock_unlock_recursive (GL(dl_load_lock));
> > +
> > + free (cur);
> > + }
> > +}
> > diff --git a/stdlib/exit.c b/stdlib/exit.c
> > index 1ad548f..78cb9f5 100644
> > --- a/stdlib/exit.c
> > +++ b/stdlib/exit.c
> > @@ -25,7 +25,6 @@
> > #include "set-hooks.h"
> > DEFINE_HOOK (__libc_atexit, (void))
> >
> > -
> > /* Call all functions registered with `atexit' and `on_exit',
> > in the reverse of the order in which they were registered
> > perform stdio cleanup, and terminate program execution with STATUS. */
> > @@ -34,6 +33,9 @@ attribute_hidden
> > __run_exit_handlers (int status, struct exit_function_list **listp,
> > bool run_list_atexit)
> > {
> > + /* First, call the TLS destructors. */
> > + __call_tls_dtors ();
> > +
> > /* We do it this way to handle recursive calls to exit () made by
> > the functions registered with `atexit' and `on_exit'. We call
> > everyone on the list and use the status value in the last
> > diff --git a/stdlib/tst-tls-atexit-lib.c b/stdlib/tst-tls-atexit-lib.c
> > new file mode 100644
> > index 0000000..45ce54d
> > --- /dev/null
> > +++ b/stdlib/tst-tls-atexit-lib.c
> > @@ -0,0 +1,37 @@
> > +/* Verify that DSO is unloaded only if its TLS objects are destroyed - the DSO.
> > + Copyright (C) 2012 Free Software Foundation, Inc.
> > + This file is part of the GNU C Library.
> > +
> > + The GNU C Library is free software; you can redistribute it and/or
> > + modify it under the terms of the GNU Lesser General Public
> > + License as published by the Free Software Foundation; either
> > + version 2.1 of the License, or (at your option) any later version.
> > +
> > + The GNU C Library is distributed in the hope that it will be useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + Lesser General Public License for more details.
> > +
> > + You should have received a copy of the GNU Lesser General Public
> > + License along with the GNU C Library; if not, see
> > + <http://www.gnu.org/licenses/>. */
> > +
> > +extern void *__dso_handle;
> > +
> > +typedef struct
> > +{
> > + void *val;
> > +} A;
> > +
> > +/* We only care about the destructor. */
> > +void A_dtor (void *obj)
> > +{
> > + ((A *)obj)->val = obj;
> > +}
> > +
> > +void do_foo (void)
> > +{
> > + static __thread A b;
> > + __cxa_thread_atexit_impl (A_dtor, &b, __dso_handle);
> > +}
> > +
> > diff --git a/stdlib/tst-tls-atexit.c b/stdlib/tst-tls-atexit.c
> > new file mode 100644
> > index 0000000..b7312cb
> > --- /dev/null
> > +++ b/stdlib/tst-tls-atexit.c
> > @@ -0,0 +1,111 @@
> > +/* Verify that DSO is unloaded only if its TLS objects are destroyed.
> > + Copyright (C) 2012 Free Software Foundation, Inc.
> > + This file is part of the GNU C Library.
> > +
> > + The GNU C Library is free software; you can redistribute it and/or
> > + modify it under the terms of the GNU Lesser General Public
> > + License as published by the Free Software Foundation; either
> > + version 2.1 of the License, or (at your option) any later version.
> > +
> > + The GNU C Library is distributed in the hope that it will be useful,
> > + but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> > + Lesser General Public License for more details.
> > +
> > + You should have received a copy of the GNU Lesser General Public
> > + License along with the GNU C Library; if not, see
> > + <http://www.gnu.org/licenses/>. */
> > +
> > +/* There are two tests in this test case. The first is implicit where it is
> > + assumed that the destructor call on exit of the LOAD function does not
> > + segfault. The other is a verification that after the thread has exited, a
> > + dlclose will unload the DSO. */
> > +
> > +#include <dlfcn.h>
> > +#include <pthread.h>
> > +#include <stdio.h>
> > +#include <unistd.h>
> > +#include <string.h>
> > +#include <errno.h>
> > +
> > +void *handle;
> > +pthread_mutex_t m = PTHREAD_MUTEX_INITIALIZER;
> > +
> > +void *
> > +load (void *u)
> > +{
> > + pthread_mutex_lock (&m);
> > + handle = dlopen ("$ORIGIN/tst-tls-atexit-lib.so", RTLD_LAZY);
> > + if (!handle)
> > + {
> > + printf ("Unable to load DSO: %s\n", dlerror ());
> > + return (void *) (uintptr_t) 1;
> > + }
> > +
> > + void (*foo) (void) = (void (*) (void)) dlsym(handle, "do_foo");
> > +
> > + if (!foo)
> > + {
> > + printf ("Unable to find symbol: %s\n", dlerror ());
> > + exit (1);
> > + }
> > +
> > + foo ();
> > +
> > + /* This should not unload the DSO. If it does, then the thread exit will
> > + result in a segfault. */
> > + dlclose (handle);
> > + pthread_mutex_unlock (&m);
> > +
> > + return NULL;
> > +}
> > +
> > +int
> > +main (void)
> > +{
> > + pthread_t t;
> > + int ret;
> > + void *thr_ret;
> > +
> > + if ((ret = pthread_create (&t, NULL, load, NULL)) != 0)
> > + {
> > + printf ("pthread_create failed: %s\n", strerror (ret));
> > + return 1;
> > + }
> > +
> > + if ((ret = pthread_join (t, &thr_ret)) != 0)
> > + {
> > + printf ("pthread_create failed: %s\n", strerror (ret));
> > + return 1;
> > + }
> > +
> > + if (thr_ret != NULL)
> > + return 1;
> > +
> > + /* Now this should unload the DSO. */
> > + dlclose (handle);
> > +
> > + /* Run through our maps and ensure that the DSO is unloaded. */
> > + FILE *f = fopen ("/proc/self/maps", "r");
> > +
> > + if (f == NULL)
> > + {
> > + perror ("Failed to open /proc/self/maps");
> > + fprintf (stderr, "Skipping verification of DSO unload\n");
> > + return 0;
> > + }
> > +
> > + char *line = NULL;
> > + size_t s = 0;
> > + while (getline (&line, &s, f) > 0)
> > + {
> > + if (strstr (line, "tst-tls-atexit-lib.so"))
> > + {
> > + printf ("DSO not unloaded yet:\n%s", line);
> > + return 1;
> > + }
> > + }
> > + free (line);
> > +
> > + return 0;
> > +}
> > diff --git a/sysdeps/unix/sysv/linux/i386/nptl/libc.abilist b/sysdeps/unix/sysv/linux/i386/nptl/libc.abilist
> > index 67d5929..3cb314d 100644
> > --- a/sysdeps/unix/sysv/linux/i386/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/i386/nptl/libc.abilist
> > @@ -1819,6 +1819,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/nptl/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/nptl/libc.abilist
> > index 8e45958..f27b48b 100644
> > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/nptl/libc.abilist
> > @@ -1781,6 +1781,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/nptl/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/nptl/libc.abilist
> > index 8eaaccd..195b587 100644
> > --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/nptl/libc.abilist
> > @@ -87,6 +87,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.3
> > GLIBC_2.3 A
> > _Exit F
> > diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/nptl/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/nptl/libc.abilist
> > index d9914ff..b6256d5 100644
> > --- a/sysdeps/unix/sysv/linux/s390/s390-32/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/s390/s390-32/nptl/libc.abilist
> > @@ -1771,6 +1771,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/nptl/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/nptl/libc.abilist
> > index ef1ead3..265f66d 100644
> > --- a/sysdeps/unix/sysv/linux/s390/s390-64/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/s390/s390-64/nptl/libc.abilist
> > @@ -92,6 +92,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/sysdeps/unix/sysv/linux/sh/nptl/libc.abilist b/sysdeps/unix/sysv/linux/sh/nptl/libc.abilist
> > index 733b550..a653292 100644
> > --- a/sysdeps/unix/sysv/linux/sh/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/sh/nptl/libc.abilist
> > @@ -92,6 +92,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/nptl/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/nptl/libc.abilist
> > index 3a96ea8..9defbdf 100644
> > --- a/sysdeps/unix/sysv/linux/sparc/sparc32/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/nptl/libc.abilist
> > @@ -1776,6 +1776,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _IO_adjust_wcolumn F
> > diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/nptl/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/nptl/libc.abilist
> > index aa892b8..35987fa 100644
> > --- a/sysdeps/unix/sysv/linux/sparc/sparc64/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/nptl/libc.abilist
> > @@ -97,6 +97,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2
> > GLIBC_2.2 A
> > _Exit F
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/64/nptl/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/nptl/libc.abilist
> > index a42d424..914b590 100644
> > --- a/sysdeps/unix/sysv/linux/x86_64/64/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/x86_64/64/nptl/libc.abilist
> > @@ -88,6 +88,9 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F
> > GLIBC_2.2.5
> > GLIBC_2.2.5 A
> > _Exit F
> > diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/nptl/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/nptl/libc.abilist
> > index 108b80f..0f64c8d 100644
> > --- a/sysdeps/unix/sysv/linux/x86_64/x32/nptl/libc.abilist
> > +++ b/sysdeps/unix/sysv/linux/x86_64/x32/nptl/libc.abilist
> > @@ -2086,3 +2086,6 @@ GLIBC_2.17
> > clock_nanosleep F
> > clock_settime F
> > secure_getenv F
> > +GLIBC_2.18
> > + GLIBC_2.18 A
> > + __cxa_thread_atexit_impl F