Enabling link-time optimizations causes a linker error?

问题

I have code which compiles and links fine.

I'm now trying to enable link-time optimizations, but adding -flto to my compiler and linker flags is causing a linker error:

/usr/local/lib/libboost_thread.a(thread.o): \
    In function `void boost::throw_exception<boost::bad_lexical_cast>(boost::bad_lexical_cast const&)':
    thread.cpp:(.text._ZN5boost15throw_exceptionINS_16bad_lexical_castEEEvRKT_[_ZN5boost15throw_exceptionINS_16bad_lexical_castEEEvRKT_]+0x124): \
        undefined reference to `vtable for boost::bad_lexical_cast'

The only flag I've added is -flto.

set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -flto" )
set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} -flto" )

To be clear:

• Without -flto the app builds and links fine
• With -flto (and no other changes), the app fails to link with the above error

What is causing this linker error?

来源：https://stackoverflow.com/questions/40350936/enabling-link-time-optimizations-causes-a-linker-error