[cfe-dev] Bug compatibility option for broken GCC 5 non-virtual thunk mangling

[Gregor Jasny via cfe-dev]

Hello,

at work we're migrating from RHEL6 to Ubuntu 16.04 (xenial) whose system 
compiler is GCC 5. For ASAN builds we use Clang 4 from the official LLVM 
apt repository.

Recently we ran into the GCC 5 "non-virtual thunk" abi_tag mangling bug 
of GCC as it is described in:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77379

https://bugs.llvm.org/show_bug.cgi?id=28997

The presence of this bug forces us to compile all of our libraries 
twice: one time with GCC 5 and one time with Clang 4. Now I wonder how 
high my chances are that someone implements a compile time switch for 
Clang to emit GCC 5 compatible object files? And getting that change 
into the stable branch of Clang 4?

Or could you envision a different band-aid like an linker script?

Thanks,
Gregor