(In reply to comment #39) > (In reply to comment #38) > > The new ABI requires the full gcc abi-tag support to be compatible with > > gcc. If you compile everything with clang and disable dual ABI support > > you can get away with less, but what is the point? Just use the clang > > libc++ instead, which requires no changes. > > [...] > > We need libc++ to work on the supported architectures with and without GNU > libraries. Getting rid of the GNU counterparts is out of the question for > any practical purpose.
So you're saying there is a use case to compile everything with clang and libstdc++? If that is actually something you need, and you don't need to be compatible to any name mangling, you just need the part of the patch in D12834 accepting abi tags and you should be fine (no dual ABI support ofc); no modifications to the name mangling (lib/AST/ItaniumMangle.cpp) are necessary for that. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to llvm-toolchain-3.6 in Ubuntu. https://bugs.launchpad.net/bugs/1488254 Title: clang++ no longer ABI-compatible with g++ Status in LLVM: Confirmed Status in llvm-toolchain-3.6 package in Ubuntu: Confirmed Bug description: $ cat foo.cc #include <string> std::string hello = "Hello, world!\n"; $ cat bar.cc #include <string> #include <iostream> extern std::string hello; int main() { std::cout << hello; return 0; } $ g++ -c foo.cc && g++ foo.o bar.cc && ./a.out Hello, world! $ clang++ -c foo.cc && clang++ foo.o bar.cc && ./a.out Hello, world! $ g++ -c foo.cc && clang++ foo.o bar.cc && ./a.out /tmp/bar-34fb23.o: In function `main': bar.cc:(.text+0x14): undefined reference to `hello' clang: error: linker command failed with exit code 1 (use -v to see invocation) $ clang++ -c foo.cc && g++ foo.o bar.cc && ./a.out /tmp/ccqU38Mh.o: In function `main': bar.cc:(.text+0x5): undefined reference to `hello[abi:cxx11]' collect2: error: ld returned 1 exit status In practice, this means that many programs using C++ libraries other than libstdc++ fail to compile with clang++. For example, mosh fails with undefined references to google::protobuf::internal::empty_string_, google::protobuf::MessageLite::InitializationErrorString() const, and google::protobuf::MessageLite::SerializeAsString() const. To manage notifications about this bug go to: https://bugs.launchpad.net/llvm/+bug/1488254/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
