On 08/13/2014 04:23 PM, Peter A. Bigot wrote:
On 08/13/2014 04:18 PM, Khem Raj wrote:
On Mon, Aug 11, 2014 at 12:02 PM, Peter A. Bigot <p...@pabigot.com>
wrote:
The program below built on the target with the MACHINE=beaglebone
gcc-4.9.1
compiler from Yocto/OpenEmbedded poky master produces this error:
beaglebone[52]$ g++ -std=c++1y -pthread test.cc && ./a.out
starting
joining
pure virtual method called
terminate called without an active exception
Aborted (core dumped)
When the program is recompiled with the defines for
__GCC_HAVE_SYNC_COMPARE_AND_SWAP_X enabled as suggested at
https://groups.google.com/d/msg/automatak-dnp3/Jisp_zGhd5I/ck_Cj6nO8joJ
it
works:
beaglebone[53]$ g++ -std=c++1y -pthread test.cc && ./a.out
starting
joining
doit
done
Preliminary analysis confirms that the built-ins for those defines
are not
being added by the compiler because it thinks the target doesn't
support
those operations. Nonetheless, it doesn't use the substitutes that are
obviously available.
Can anybody recall anything about the way GCC is built under OE that
would
explain this?
Can you add -mcpu=cortex-a8 to your cmdline and see if it solves the
problem ?
Yes, it does. That's a good clue.
More specifically, the build logs say gcc-runtime was built with:
arm-poky-linux-gnueabi-gcc -march=armv7-a -mthumb-interwork
-mfloat-abi=hard -mfpu=neon -mtune=cortex-a8
and using those flags instead of -mcpu=cortex-a8 also solves the problem.
So either gcc-runtime needs to stop using those flags, or gcc itself
needs to default to them. Or some other solution.
In any case, Khem can you run with this? It'd be fixed a lot better
that way....
Peter
Peter
Peter
/* g++ -std=c++1y -pthread test.cc && ./a.out */
#if 0
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_1
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_2
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_4
#define __GCC_HAVE_SYNC_COMPARE_AND_SWAP_8
#endif
#include <iostream>
#include <thread>
void
doit ()
{
std::cerr << "doit\n";
}
int main (int argc,
char * argv [])
{
std::cerr << "starting\n";
std::thread thr{doit};
std::cerr << "joining\n";
thr.join();
std::cerr << "done\n";
return 0;
}
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