On 11/09/2020 10:48, Heinz Junkes wrote:
Here is a mail I received from a colleague.
It concerns thereby an "old" problem which seemed already solved?
FYI. I can run the unit tests, but I'm seeing a couple of hangs.
The first I'm looking at is epicsTimeTest which seems to be
related to c++ exception handling. I recall that there were
problems with x86 exception handling, but I also recall hearing
that this was fixed.
...
***** Starting EPICS application *****
1..212
ok 1 - epicsTime_gmtime() for EPICS epoch
ok 2 - nanosecond overflow throws
... hangs ...
Attaching debugger shows:
Program received signal SIGINT, Interrupt.
libat_fetch_add_4 (mptr=0x757730, opval=4294967295, smodel=5) at
../../../../gcc-7.5.0/libatomic/fop_n.c:44
44 ../../../../gcc-7.5.0/libatomic/fop_n.c: No such file or directory.
(gdb) bt
#0 libat_fetch_add_4 (mptr=0x757730, opval=4294967295, smodel=5) at
../../../../gcc-7.5.0/libatomic/fop_n.c:44
#1 0x003b07fc in __gnu_cxx::__exchange_and_add (__val=-1, __mem=0x757730)
at
/home/mdavidsaver/source/rtems/rtems-source-builder-5.1/rtems/build/i386-rtems5-gcc-7.5.0-newlib-7947581-x86_64-linux-gnu-1/build/i386-rtems5/mpentiumpro/libstdc++-v3/include/ext/atomicity.h:49
#2 __gnu_cxx::__exchange_and_add_dispatch (__val=-1, __mem=0x757730)
at
/home/mdavidsaver/source/rtems/rtems-source-builder-5.1/rtems/build/i386-rtems5-gcc-7.5.0-newlib-7947581-x86_64-linux-gnu-1/build/i386-rtems5/mpentiumpro/libstdc++-v3/include/ext/atomicity.h:82
#3 __gnu_cxx::__eh_atomic_dec (__count=0x757730) at
../../../../../gcc-7.5.0/libstdc++-v3/libsupc++/eh_atomics.h:72
#4 __gxx_exception_cleanup (code=_URC_FOREIGN_EXCEPTION_CAUGHT, exc=0x757770)
at ../../../../../gcc-7.5.0/libstdc++-v3/libsupc++/eh_throw.cc:46
#5 0x003ad9cb in _Unwind_DeleteException (exc=0x757770) at
../../../../gcc-7.5.0/libgcc/unwind.inc:271
#6 0x003af8d0 in __cxxabiv1::__cxa_end_catch () at
../../../../../gcc-7.5.0/libstdc++-v3/libsupc++/eh_catch.cc:125
#7 0x001012fd in epicsTimeTest () at ../epicsTimeTest.cpp:116
(gdb)
There is also an associated ticket:
http://devel.rtems.org/ticket/2830
I think the i386 BSPs need to be cleaned up to use an instruction set
which fits current the x86 hardware. I mean hardware which is still in
use and not some stuff from the 1990s.
For example if I compile this test
#include <stdatomic.h>
int add(atomic_int *i, int v)
{
return atomic_fetch_add(i, v);
}
on my Linux machine, I get:
gcc -O2 -S -o - test.c -m32
.file "test.c"
.text
.p2align 4,,15
.globl add
.type add, @function
add:
.LFB0:
.cfi_startproc
movl 4(%esp), %edx
movl 8(%esp), %eax
lock xaddl %eax, (%edx)
ret
.cfi_endproc
.LFE0:
.size add, .-add
.ident "GCC: (SUSE Linux) 7.5.0"
.section .note.GNU-stack,"",@progbits
There is no call to libatomic.
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