[package] folly/2020.08.10.00: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'

Package and Environment Details (include every applicable attribute)

• Package Name/Version: folly/2020.08.10.00
• Operating System+version: Linux Ubuntu 18.04
• Compiler+version: GCC 9
• Conan version: conan 1.30.2
• Python version: Python 3.7.4

Conan profile (output of conan profile show default or conan profile show <profile> if custom profile is in use)

[settings]
os=Linux
os_build=Linux
arch=x86_64
arch_build=x86_64
compiler=gcc
compiler.version=9
compiler.libcxx=libstdc++
build_type=Release
[options]
[build_requires]
[env]

Steps to reproduce (Include if Applicable)

Link using folly/2020.08.10.00. You get undefined symbols like

undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'

The reason is because of link ordering within Folly. The recipe uses collect_libs(). Replacing collect_libs() library ordering fixes the problem:

        self.cpp_info.components["libfolly"].libs = [
            "folly_exception_counter",
            "folly_exception_tracer",
            "folly_exception_tracer_base",
            "folly_test_util",
            "follybenchmark",
            "folly"
        ]

Logs (Include/Attach if Applicable)

Click to expand log

/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::Synchronized<std::vector<void (*)(void*, std::type_info*, void (**)(void*)), std::allocator<void (*)(void*, std::type_info*, void (**)(void*))> >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >::Synchronized()':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/Synchronized.h:513: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::Synchronized<std::vector<void (*)(void*), std::allocator<void (*)(void*)> >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >::Synchronized()':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/Synchronized.h:513: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::Synchronized<std::vector<void (*)(), std::allocator<void (*)()> >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >::Synchronized()':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/Synchronized.h:513: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::Synchronized<std::vector<void (*)(std::__exception_ptr::exception_ptr), std::allocator<void (*)(std::__exception_ptr::exception_ptr)> >, folly::SharedMutexImpl<false, void, std::atomic, false, false> >::Synchronized()':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/Synchronized.h:513: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::SharedMutexImpl()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::detail::LockTraitsImpl<folly::SharedMutexImpl<false, void, std::atomic, false, false>, (folly::detail::MutexLevel)1, false>::unlock_shared(folly::SharedMutexImpl<false, void, std::atomic, false, false>&)':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/LockTraits.h:164: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::unlock_shared()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::detail::LockTraitsImpl<folly::SharedMutexImpl<false, void, std::atomic, false, false>, (folly::detail::MutexLevel)0, false>::unlock(folly::SharedMutexImpl<false, void, std::atomic, false, false>&)':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/LockTraits.h:131: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::unlock()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::detail::LockTraitsImpl<folly::SharedMutexImpl<false, void, std::atomic, false, false>, (folly::detail::MutexLevel)0, false>::lock(folly::SharedMutexImpl<false, void, std::atomic, false, false>&)':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/LockTraits.h:124: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::lock()'
/usr/bin/ld: /home/pfraval/.conan/data/folly/2020.08.10.00/_/_/package/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/lib/libfolly_exception_tracer.a(ExceptionTracerLib.cpp.o): in function `folly::detail::LockTraitsImpl<folly::SharedMutexImpl<false, void, std::atomic, false, false>, (folly::detail::MutexLevel)1, false>::lock_shared(folly::SharedMutexImpl<false, void, std::atomic, false, false>&)':
/home/conan/w/cci_PR-2363/.conan/data/folly/2020.08.10.00/_/_/build/d474cd0f413a68e19aaa3dc823ff9d479ab99b7c/source_subfolder/folly/LockTraits.h:157: undefined reference to `folly::SharedMutexImpl<false, void, std::atomic, false, false>::lock_shared()'
collect2: error: ld returned 1 exit status
make[2]: *** [tw/service/test/CMakeFiles/service-test-runner.dir/build.make:555: bin/service-test-runner] Error 1
make[2]: Leaving directory '/home/pfraval/dev/ifi/base/cmake-build-debug'
make[1]: *** [CMakeFiles/Makefile2:1706: tw/service/test/CMakeFiles/service-test-runner.dir/all] Error 2
make[1]: Leaving directory '/home/pfraval/dev/ifi/base/cmake-build-debug'
make: *** [Makefile:160: all] Error 2

[sourcedelica]

I couldn’t figure out how to replicate the original problem, but I could replicate this other undefined reference which is very similar:

/usr/bin/ld: /home/eric/.conan/data/folly/2020.08.10.00/_/_/package/b8af69894efc20cc2a5098146dca4122c1f071fe/lib/libfolly_exception_tracer_base.a(ExceptionTracer.cpp.o): in function `folly::exception_tracer::printExceptionInfo(std::ostream&, folly::exception_tracer::ExceptionInfo const&, int)':
ExceptionTracer.cpp:(.text+0x23c): undefined reference to `folly::symbolizer::Symbolizer::Symbolizer(folly::symbolizer::ElfCacheBase*, folly::symbolizer::LocationInfoMode, unsigned long)'
/usr/bin/ld: ExceptionTracer.cpp:(.text+0x25e): undefined reference to `folly::symbolizer::Symbolizer::symbolize(folly::Range<unsigned long const*>, folly::Range<folly::symbolizer::SymbolizedFrame*>)'
/usr/bin/ld: ExceptionTracer.cpp:(.text+0x271): undefined reference to `folly::symbolizer::OStreamSymbolizePrinter::OStreamSymbolizePrinter(std::ostream&, int)'
/usr/bin/ld: ExceptionTracer.cpp:(.text+0x281): undefined reference to `folly::symbolizer::SymbolizePrinter::println(folly::symbolizer::SymbolizedFrame const*, unsigned long)'
/usr/bin/ld: /home/eric/.conan/data/folly/2020.08.10.00/_/_/package/b8af69894efc20cc2a5098146dca4122c1f071fe/lib/libfolly_exception_tracer_base.a(ExceptionTracer.cpp.o): in function `folly::exception_tracer::printExceptionInfo(std::ostream&, folly::exception_tracer::ExceptionInfo const&, int) [clone .cold]':
ExceptionTracer.cpp:(.text.unlikely+0xc3): undefined reference to `folly::exceptionStr(std::exception const&)'
/usr/bin/ld: /home/eric/.conan/data/folly/2020.08.10.00/_/_/package/b8af69894efc20cc2a5098146dca4122c1f071fe/lib/libfolly_exception_tracer_base.a(StackTrace.cpp.o): in function `folly::exception_tracer::StackTraceStack::pushCurrent()':
StackTrace.cpp:(.text+0x75): undefined reference to `folly::symbolizer::getStackTrace(unsigned long*, unsigned long)'
collect2: error: ld returned 1 exit status

By adding the following to test_package.cpp:

#include <folly/experimental/exception_tracer/ExceptionTracer.h>

And then in main():

    folly::exception_tracer::installHandlers();

Tested your PR - it fixes the problem.

[prince-chrismc]

Can you please share some sample code that I can add to the test_package to make sure this is fixed? feel free to test the PR i opened