qt5base-lts/config.tests
Thiago Macieira 3d7586b760 Auto-detect whether 64-bit std::atomic really works
The C++ standard says it must, but some badly-configured toolchains seem
to be lacking support.

In particular, for some 32-bit platforms without native support for
them, GCC implements 64-bit atomics via out-of-line functions in
libatomic. If that library is missing... well, then std::atomic 64-bit
doesn't work and we mustn't try to use it.

This was found when trying to compile Qt 5.6 for MIPS 32-bit:

Linking library libQt5Core.so.5.6.0
.obj/qsimd.o: In function `std::__atomic_base<unsigned long long>::load(std::memory_order) const':
/opt/poky/1.7/sysroots/mips32r2-poky-linux/usr/include/c++/4.9.1/bits/atomic_base.h:500: undefined reference to `__atomic_load_8'
.obj/qsimd.o: In function `std::__atomic_base<unsigned long long>::store(unsigned long long, std::memory_order)':
/opt/poky/1.7/sysroots/mips32r2-poky-linux/usr/include/c++/4.9.1/bits/atomic_base.h:478: undefined reference to `__atomic_store_8'

Yocto bug report: https://bugzilla.yoctoproject.org/show_bug.cgi?id=8274

Change-Id: I42e7ef1a481840699a8dffff140224d6614e5c36
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
2015-09-22 22:46:08 +00:00
..
arch Update the list of x86 instruction set extensions enabled by GCC 2015-07-28 23:55:04 +00:00
common Auto-detect whether 64-bit std::atomic really works 2015-09-22 22:46:08 +00:00
mac/corewlan Fixed license headers 2015-02-17 18:46:09 +00:00
qpa Add Mir client platform plugin 2015-08-09 06:27:26 +00:00
unix Fix pointer size detection when cross-compiling 2015-08-21 12:43:41 +00:00
win/directwrite Windows: Include DirectWrite support by default if available 2015-07-21 08:21:34 +00:00
x11 Update copyright headers 2015-02-11 06:49:51 +00:00
.gitignore Initial import from the monolithic Qt. 2011-04-27 12:05:43 +02:00
.qmake.conf Handle INCLUDE and LIB environment variables in config.tests for MinGW 2013-11-22 07:30:57 +01:00