Date: Tue, 08 Aug 2017 18:52:05 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-toolchain@FreeBSD.org Subject: [Bug 221288] lang/gcc5 links against libsupc++ when compiling Message-ID: <bug-221288-29464-bgWHSIZkNL@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-221288-29464@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=221288 --- Comment #5 from Mark Millard <markmi@dsl-only.net> --- I suspect this mix of infrastructures ties in to why standard c++ threading fails under the likes of g++6 compiles while the code works when compiled and linked via system clang++ 5. The infrastructure issues may extend to the libgcc_s that is used as well. (The program here is just one that I happen to have around, not minimized, but standard C++ code only.) Starting without an explicit -pthread : g++6 -std=c++14 -Wpedantic -Wall -Wl,-rpath=/usr/local/lib/gcc6 -O2 cpp_clocks_investigation.cpp (So no -pthread explicitly.) Note the lack of both libthr.so.3 and libcxxrt.so.1 in the below. Also the libgcc_s being from gcc6 materials. # ldd a.out a.out: libstdc++.so.6 => /usr/local/lib/gcc6/libstdc++.so.6 (0x800844000) libm.so.5 => /lib/libm.so.5 (0x800bd9000) libgcc_s.so.1 => /usr/local/lib/gcc6/libgcc_s.so.1 (0x800e06000) libc.so.7 => /lib/libc.so.7 (0x80101d000) leads to: static inline int __gthread_create (__gthread_t *__threadid, void *(*__func) (void*), void *__args) { return __gthrw_(pthread_create) (__threadid, NULL, __func, __args); } getting SIGSEGV from pthread_create not having a good address. With -pthread the a.out produced gets a SIGSEGV in infrustrature. Showing similar to the above information: g++6 -std=c++14 -Wpedantic -Wall -pthread -Wl,-rpath=/usr/local/lib/gcc6 -O2 cpp_clocks_investigation.cpp Note the libthr.so.3 but the lack of libcxxrt.so.1 in the below. Also the libgcc_s being from gcc6 materials. # ldd a.out a.out: libstdc++.so.6 => /usr/local/lib/gcc6/libstdc++.so.6 (0x800844000) libm.so.5 => /lib/libm.so.5 (0x800bd9000) libgcc_s.so.1 => /usr/local/lib/gcc6/libgcc_s.so.1 (0x800e06000) libthr.so.3 => /lib/libthr.so.3 (0x80101d000) libc.so.7 => /lib/libc.so.7 (0x801245000) (run in /usr/local/bin/gdb :) Thread 11 received signal SIGSEGV, Segmentation fault. [Switching to LWP 100288 of process 18022] uw_frame_state_for (context=context@entry=0x7fffdfdfce20, fs=fs@entry=0x7fffdfdfcb70) at /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.4.0/libgcc/unwind-dw2.c:1249 1249 return MD_FALLBACK_FRAME_STATE_FOR (context, fs); (gdb) bt #0 uw_frame_state_for (context=context@entry=0x7fffdfdfce20, fs=fs@entry=0x7fffdfdfcb70) at /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.4.0/libgcc/unwind-dw2.c:1249 #1 0x0000000800e1602b in _Unwind_ForcedUnwind_Phase2 (exc=exc@entry=0x80069cc30, context=context@entry=0x7fffdfdfce20) at /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.4.0/libgcc/unwind.inc:155 #2 0x0000000800e16364 in _Unwind_ForcedUnwind (exc=0x80069cc30, stop=0x801033450 <thread_unwind_stop>, stop_argument=<optimized out>) at /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.4.0/libgcc/unwind.inc:207 #3 0x00000008010332b3 in _Unwind_ForcedUnwind (ex=<optimized out>, stop_func=0x7fffdfdfc948, stop_arg=0x80069ca00) at /usr/src/lib/libthr/thread/thr_exit.c:106 #4 thread_unwind () at /usr/src/lib/libthr/thread/thr_exit.c:172 #5 _pthread_exit_mask (status=<optimized out>, mask=<optimized out>) at /usr/src/lib/libthr/thread/thr_exit.c:254 #6 0x00000008010330db in _pthread_exit (status=0x80069ca00) at /usr/src/lib/libthr/thread/thr_exit.c:206 #7 0x0000000801025c0d in thread_start (curthread=0x80069ca00) at /usr/src/lib/libthr/thread/thr_create.c:289 #8 0x00007fffdfbfd000 in ?? () Backtrace stopped: Cannot access memory at address 0x7fffdfdfd000 Note #3 -> #4 goes from: /usr/src/lib/libthr/thread/thr_exit.c: to: /usr/obj/portswork/usr/ports/lang/gcc6/work/gcc-6.4.0/libgcc/unwind.inc So: from system libthr to gcc6's libgcc . System clang++ 5 with -pthread (link fails without it): clang++ -std=c++14 -Wpedantic -Wall -pthread cpp_clocks_investigation.cpp # ldd a.out a.out: libc++.so.1 => /usr/lib/libc++.so.1 (0x8008a6000) libcxxrt.so.1 => /lib/libcxxrt.so.1 (0x800b72000) libm.so.5 => /lib/libm.so.5 (0x800d90000) libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x800fbd000) libthr.so.3 => /lib/libthr.so.3 (0x8011d3000) libc.so.7 => /lib/libc.so.7 (0x8013fb000) This a.out runs to completion just fine. -- You are receiving this mail because: You are the assignee for the bug.home | help
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