mirror of
https://github.com/ceph/ceph
synced 2024-12-11 14:09:09 +00:00
4c726846e4
we have following error when trying to compile the C++ source
file on mipsel:
/usr/bin/c++ -DHAVE_CXX11_ATOMIC -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -g1 -Wdate-time -D_FORTIFY_SOURCE=2 -std=c++11 -fPIE -o CMakeFiles/cmTC_9f34f.dir/src.cxx.o -c /<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx
/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx:15:44: error: template argument 1 is invalid
15 | bool atomic16(std::atomic<unsigned __int128> *ptr)
| ^
/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx:15:44: error: template argument 1 is invalid
/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx:15:44: error: template argument 1 is invalid
/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx:15:44: error: template argument 1 is invalid
/<<PKGBUILDDIR>>/obj-mipsel-linux-gnu/CMakeFiles/CMakeTmp/src.cxx:15:47: error: ‘ptr’ was not declared in this scope
15 | bool atomic16(std::atomic<unsigned __int128> *ptr)
| ^~~
the compiler was GCC 11.2.0.
in this change, instead of detecting the architecture, check for
the macro of `__SIZEOF_INT128__`, which is respected by GCC and Clang.
so it's more readable. also, instead of using the `unsigned __int128`
type provided as a GCC extension, use a struct to mimic the use case
of boost::lockfree library.
Signed-off-by: Kefu Chai <tchaikov@gmail.com>
70 lines
2.0 KiB
CMake
70 lines
2.0 KiB
CMake
# some platforms do not offer support for atomic primitive for all integer
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# types, in that case we need to link against libatomic
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include(CheckCXXSourceCompiles)
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include(CMakePushCheckState)
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function(check_cxx_atomics var)
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set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -std=c++11")
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check_cxx_source_compiles("
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#include <atomic>
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#include <cstdint>
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#include <cstddef>
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#if defined(__SIZEOF_INT128__)
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// Boost needs 16-byte atomics for tagged pointers.
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// These are implemented via inline instructions on the platform
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// if 16-byte alignment can be proven, and are delegated to libatomic
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// library routines otherwise. Whether or not alignment is provably
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// OK for a std::atomic unfortunately depends on compiler version and
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// optimization levels, and also on the details of the expression.
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// We specifically test access via an otherwise unknown pointer here
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// to ensure we get the most complex case. If this access can be
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// done without libatomic, then all accesses can be done.
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struct tagged_ptr {
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int* ptr;
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std::size_t tag;
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};
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void atomic16(std::atomic<tagged_ptr> *ptr)
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{
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tagged_ptr p{nullptr, 1};
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ptr->store(p);
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tagged_ptr f = ptr->load();
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tagged_ptr new_tag{nullptr, 0};
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ptr->compare_exchange_strong(f, new_tag);
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}
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#endif
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int main() {
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#if defined(__SIZEOF_INT128__)
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std::atomic<tagged_ptr> ptr;
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atomic16(&ptr);
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#endif
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std::atomic<uint8_t> w1;
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std::atomic<uint16_t> w2;
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std::atomic<uint32_t> w4;
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std::atomic<uint64_t> w8;
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return w1 + w2 + w4 + w8;
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}
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" ${var})
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endfunction(check_cxx_atomics)
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cmake_push_check_state()
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check_cxx_atomics(HAVE_CXX11_ATOMIC)
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cmake_pop_check_state()
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if(NOT HAVE_CXX11_ATOMIC)
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cmake_push_check_state()
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set(CMAKE_REQUIRED_LIBRARIES "atomic")
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check_cxx_atomics(HAVE_LIBATOMIC)
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cmake_pop_check_state()
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if(HAVE_LIBATOMIC)
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set(LIBATOMIC_LINK_FLAGS "-Wl,--as-needed -latomic")
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else()
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message(FATAL_ERROR
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"Host compiler ${CMAKE_CXX_COMPILER} requires libatomic, but it is not found")
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endif()
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endif()
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