* __sync_-builtins cause undefined references on some sparc targets @ 2017-02-27 15:55 Jan.Sommer 2017-02-27 21:08 ` Eric Botcazou 0 siblings, 1 reply; 7+ messages in thread From: Jan.Sommer @ 2017-02-27 15:55 UTC (permalink / raw) To: gcc; +Cc: devel Hello, I compiled the gcc 6.3.0 for the leon2 processor for RTEMS (i.e. sparc-rtems4.12-*). When linking a fortran program for the leon2 processor I get undefined references for `__sync_bool_compare_and_swap_4' (see below). According to the discussion on the rtems mailinglist the __sync_*-operations are legacy and __atomic_*-operations should be used instead or to quote: "This __sync_() stuff seems to be used in several places in GCC. So, changing libbacktrace is probably not enough. We need a general solution for the __sync_() builtins on RTEMS. I don't think GCC can be changed to emit __atomic_() calls for the __sync_() builtins (I would still try to ask). The libgcc or libatomic is probably a good place to add them for RTEMS as functions implemented via __atomic_() builtins." Could someone give me some recommendations on what would be the best solution to fix the problem and maybe some pointers on how to start? I put the rtems mailinglist CC, so they can comment as well. sparc-rtems4.12-gcc -B../../../../../leon2/lib/ -specs bsp_specs -qrtems -mcpu=cypress -mhard-float -O2 -g -ffunction-sections -fdata-sections -Wall -Wmissing-prototypes -Wimplicit-function-declaration -Wstrict-prototypes -Wnested-externs -Wl,--gc-sections -mcpu=cypress -mhard-float -o ticker.exe init.o tasks.o -L/localdata/somm_ja/rtems-fortran/install/bsps/4.12/sparc/sparc-rtems4.12/leon2/lib/ -llapack -lrefblas -ltmglib -lcblas -lm -lgfortran -lgcc /localdata/somm_ja/rtems-fortran/install/tools/4.12/sparc/lib/gcc/sparc-rtems4.12/6.3.0/libgfortran.a(elf.o): In function `backtrace_initialize': /localdata/somm_ja/rtems-fortran/rtems-source-builder/rtems/build/sparc-rtems4.12-gcc-6.3.0-newlib-2.5.0-x86_64-linux-gnu-1/build/sparc-rtems4.12/libbacktrace/../../../gcc-6.3.0/libbacktrace/elf.c:960: undefined reference to `__sync_bool_compare_and_swap_4' /localdata/somm_ja/rtems-fortran/install/tools/4.12/sparc/lib/gcc/sparc-rtems4.12/6.3.0/libgfortran.a(elf.o): In function `elf_add_syminfo_data': /localdata/somm_ja/rtems-fortran/rtems-source-builder/rtems/build/sparc-rtems4.12-gcc-6.3.0-newlib-2.5.0-x86_64-linux-gnu-1/build/sparc-rtems4.12/libbacktrace/../../../gcc-6.3.0/libbacktrace/elf.c:456: undefined reference to `__sync_bool_compare_and_swap_4' /localdata/somm_ja/rtems-fortran/install/tools/4.12/sparc/lib/gcc/sparc-rtems4.12/6.3.0/libgfortran.a(dwarf.o): In function `backtrace_dwarf_add': /localdata/somm_ja/rtems-fortran/rtems-source-builder/rtems/build/sparc-rtems4.12-gcc-6.3.0-newlib-2.5.0-x86_64-linux-gnu-1/build/sparc-rtems4.12/libbacktrace/../../../gcc-6.3.0/libbacktrace/dwarf.c:3030: undefined reference to `__sync_bool_compare_and_swap_4' collect2: error: ld returned 1 exit status Makefile:627: recipe for target 'ticker.exe' failed make: *** [ticker.exe] Error 1 Best regards, Jan Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR) German Aerospace Center Simulation and Software Technology | Software for Space Systems and Interactive Visualization | Lilienthalplatz 7 | 38108 Braunschweig | Germany Jan Sommer Telephone +49 531 295-2494 | Telefax 0531 295-2767 | jan.sommer@dlr.de DLR.de/SC ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: __sync_-builtins cause undefined references on some sparc targets 2017-02-27 15:55 __sync_-builtins cause undefined references on some sparc targets Jan.Sommer @ 2017-02-27 21:08 ` Eric Botcazou 2017-02-27 21:14 ` Jan Sommer 0 siblings, 1 reply; 7+ messages in thread From: Eric Botcazou @ 2017-02-27 21:08 UTC (permalink / raw) To: Jan.Sommer; +Cc: gcc, devel > "This __sync_() stuff seems to be used in several places in GCC. So, > changing libbacktrace is probably not enough. We need a general solution > for the __sync_() builtins on RTEMS. I don't think GCC can be changed to > emit __atomic_() calls for the __sync_() builtins (I would still try to > ask). The libgcc or libatomic is probably a good place to add them for > RTEMS as functions implemented via __atomic_() builtins." > > Could someone give me some recommendations on what would be the best > solution to fix the problem and maybe some pointers on how to start? I'm not sure backtrace support has much interest on embedded platforms and I don't think implementing atomic operations makes any sense on LEON2, so the best thing to do is probably to kludge around it in libgfortran. -- Eric Botcazou ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: __sync_-builtins cause undefined references on some sparc targets 2017-02-27 21:08 ` Eric Botcazou @ 2017-02-27 21:14 ` Jan Sommer 2017-02-27 21:29 ` Eric Botcazou 0 siblings, 1 reply; 7+ messages in thread From: Jan Sommer @ 2017-02-27 21:14 UTC (permalink / raw) To: gcc, devel; +Cc: Eric Botcazou On Montag, 27. Februar 2017 22:07:56 CET Eric Botcazou wrote: > > "This __sync_() stuff seems to be used in several places in GCC. So, > > changing libbacktrace is probably not enough. We need a general solution > > for the __sync_() builtins on RTEMS. I don't think GCC can be changed to > > emit __atomic_() calls for the __sync_() builtins (I would still try to > > ask). The libgcc or libatomic is probably a good place to add them for > > RTEMS as functions implemented via __atomic_() builtins." > > > > Could someone give me some recommendations on what would be the best > > solution to fix the problem and maybe some pointers on how to start? > > I'm not sure backtrace support has much interest on embedded platforms and I > don't think implementing atomic operations makes any sense on LEON2, so the > best thing to do is probably to kludge around it in libgfortran. > Is there an easy way to remove the libbacktrace dependency? Might something like that work?: https://patchwork.ozlabs.org/patch/553017/ ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: __sync_-builtins cause undefined references on some sparc targets 2017-02-27 21:14 ` Jan Sommer @ 2017-02-27 21:29 ` Eric Botcazou 2017-03-03 12:07 ` Jan.Sommer 0 siblings, 1 reply; 7+ messages in thread From: Eric Botcazou @ 2017-02-27 21:29 UTC (permalink / raw) To: Jan Sommer; +Cc: gcc, devel > Is there an easy way to remove the libbacktrace dependency? > Might something like that work?: https://patchwork.ozlabs.org/patch/553017/ Yes, even better, simply arrange for the __sync and __atomic support tests of libbacktrace to fail on your target, possibly by using the same trick as HPUX. -- Eric Botcazou ^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: __sync_-builtins cause undefined references on some sparc targets 2017-02-27 21:29 ` Eric Botcazou @ 2017-03-03 12:07 ` Jan.Sommer 2017-03-03 12:23 ` Eric Botcazou 0 siblings, 1 reply; 7+ messages in thread From: Jan.Sommer @ 2017-03-03 12:07 UTC (permalink / raw) To: ebotcazou, soja-lists; +Cc: gcc > -----Original Message----- > From: gcc-owner@gcc.gnu.org [mailto:gcc-owner@gcc.gnu.org] On Behalf Of > Eric Botcazou > Sent: Monday, February 27, 2017 10:30 PM > To: Jan Sommer > Cc: gcc@gcc.gnu.org; devel@rtems.org > Subject: Re: __sync_-builtins cause undefined references on some sparc targets > > > Is there an easy way to remove the libbacktrace dependency? > > Might something like that work?: > > https://patchwork.ozlabs.org/patch/553017/ > > Yes, even better, simply arrange for the __sync and __atomic support tests of > libbacktrace to fail on your target, possibly by using the same trick as HPUX. Ok. I set libbacktrace_cv_sys_sync=no for my target and the undefined referenced disappeared. However I am not sure I understand what that means now. Is libbacktrace excluded from the build, or is it build but broken? Cheers, Jan > > -- > Eric Botcazou ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: __sync_-builtins cause undefined references on some sparc targets 2017-03-03 12:07 ` Jan.Sommer @ 2017-03-03 12:23 ` Eric Botcazou 2017-03-03 12:35 ` Sebastian Huber 0 siblings, 1 reply; 7+ messages in thread From: Eric Botcazou @ 2017-03-03 12:23 UTC (permalink / raw) To: Jan.Sommer; +Cc: gcc, soja-lists > Is libbacktrace excluded from the build, or is it build but broken? Neither, it's presumably falls back to __atomic. No big deal in any case, since you'll presumably never use libbacktrace in practice. -- Eric Botcazou ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: __sync_-builtins cause undefined references on some sparc targets 2017-03-03 12:23 ` Eric Botcazou @ 2017-03-03 12:35 ` Sebastian Huber 0 siblings, 0 replies; 7+ messages in thread From: Sebastian Huber @ 2017-03-03 12:35 UTC (permalink / raw) To: Eric Botcazou, Jan.Sommer; +Cc: gcc, soja-lists On 03/03/17 13:23, Eric Botcazou wrote: >> Is libbacktrace excluded from the build, or is it build but broken? > Neither, it's presumably falls back to __atomic. No big deal in any case, > since you'll presumably never use libbacktrace in practice. > We have (libgcc/config/gthr-rtems.h) static inline int __gthread_active_p (void) { return 1; } and (libgfortran/runtime/backtrace.c) void show_backtrace (bool in_signal_handler) { struct backtrace_state *lbstate; struct mystate state = { 0, false, in_signal_handler }; lbstate = backtrace_create_state (NULL, __gthread_active_p (), error_callback, NULL); and (libgfortran/runtime/backtrace.c) struct backtrace_state * backtrace_create_state (const char *filename, int threaded, backtrace_error_callback error_callback, void *data) { struct backtrace_state init_state; struct backtrace_state *state; #ifndef HAVE_SYNC_FUNCTIONS if (threaded) { error_callback (data, "backtrace library does not support threads", 0); return NULL; } #endif So, I doubt this works for RTEMS. I guess libgfortran needs an option to be a bit less verbose on some targets. -- Sebastian Huber, embedded brains GmbH Address : Dornierstr. 4, D-82178 Puchheim, Germany Phone : +49 89 189 47 41-16 Fax : +49 89 189 47 41-09 E-Mail : sebastian.huber@embedded-brains.de PGP : Public key available on request. Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2017-03-03 12:35 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2017-02-27 15:55 __sync_-builtins cause undefined references on some sparc targets Jan.Sommer 2017-02-27 21:08 ` Eric Botcazou 2017-02-27 21:14 ` Jan Sommer 2017-02-27 21:29 ` Eric Botcazou 2017-03-03 12:07 ` Jan.Sommer 2017-03-03 12:23 ` Eric Botcazou 2017-03-03 12:35 ` Sebastian Huber
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