Linking fail on Linux with clang and libc++ or libstdc++.

[canatella]

Please fill in the following fields:

Pre-built SDK from the website or open-source from this repo: prebuilt
Firebase C++ SDK version: 6.15.0
Firebase plugins in use (Auth, Database, etc.): app, auth, firestore
Additional SDKs you are using (Facebook, AdMob, etc.): n/a
Platform you are using the C++ SDK on (Mac, Windows, or Linux): Linux
Platform you are targeting (iOS, Android, and/or desktop): desktop

Please describe the issue here:

Linking fails on Linux when linking against libc++ or with libstdc++.

• Compiler is clang 9.0.0,
• linker is lld 7.0.1,
• libc++ is 7.0.1 and
• libstdc++ is 8.3.0.

The readme says that the lib is build with GCC 4.8+, libc++ but as it did not build with libc++ I also tried with libstdc++ but it did not work neither. Could you confirm which compiler, stdlib version are needed ? If gcc is expected, it would be nice to have a clang build also: all other unixy platforms support clang but Linux.

libc++ error:

ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >)

libstdc++ error:

ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

Please answer the following, if applicable:

Have you been able to reproduce this issue with just the Firebase C++ quickstarts ? Did not try.

What's the issue repro rate? (eg 100%, 1/5 etc)

[patm1987]

Hi Canatella!

It would help if you tried to build/link the Firestore C++ project, but on Linux it's not uncommon to experience linker issues between different user environments (especially since Firestore exposes a C++ API rather than a C API). For that reason, I do highly recommend using the open source C++ SDK when using Firebase on the desktop. Note that the binary and source distributions are identical, so you're not losing anything other than some extra time on a clean build (I do delve a little into this on this article comparing the binary and source C++ distributions of Firebase, and I do a brief walkthrough of adding the Firebase SDK to a desktop game here).

Let me know if you believe that this adequately addresses your issue!

--Patrick

[canatella]

Hello Patrick, thanks for help. I would indeed build the open source version but last time I tried, the pre-compiled version (6.14.0) had fixes that the open source had not and the documentation on the firebase website was not matching the open source neither. I'm just guessing from the outside here but it seemed to me that 6.14.0, 6.14.1 and 6.15.0 were released without this repository being updated. I think the repo has been updated now and that is great but I'm afraid I'll switch to the open source version (with loooots of stuff to integrate the build with conan) only to have to switch back to the pre-compiled version in one month because the open source is out dated again.

[patm1987]

That stinks, and certainly wasn't intentional 😢 (a brief amount of investigation shows that there was a bug in the process by which the source code is moved to the public repo - which appears to have been fixed).

My recommendation would still stand to use the open source release if possible. But if you'd like to explore the linker errors, can you share more of your error log - specifically the command line invocation of your link step and the logs leading up to your error? I want to make sure that you're linking libfirebase_firestore.a for the correct architecture (i386 or x86_64) and that there's nothing unexpected in your invocation. With all the caveats above, I believe that the wrong libc++ should be a different linker error if you're just linking precompiled binaries.

To answer one of your questions in the original report: GCC would be expected - although Clang claims broad compatibility with GCC. For now assume that GCC 4.8+ is correct - my own environment has 9.3.0 but I'll make sure to update this bug (and the readme) if I find out anything more specific.

[canatella]

Good to know that they are supposed to be in sync now. I'll switch to the source version when I get the time. To check if I linked against the correct version, there is nothing much I can do now, I switched the CI to build on mac to avoid the problem as we are in kind of a hurry here. But this is the part of the conanfile.py that install the Linux static libs:

    @property
    def lib_path(self):
        if self.settings.os == "Macos":
            return '/firebase_cpp_sdk/libs/darwin/x86_64'
        if self.settings.os == "iOS" and self.settings.arch == 'armv8':
            return '/firebase_cpp_sdk/libs/ios/arm64'
        if self.settings.os == "iOS" and self.settings.arch == 'x86_64':
            return '/firebase_cpp_sdk/libs/ios/x86_64'
        if self.settings.os == "Android" and self.settings.arch == 'armv8':
            return '/firebase_cpp_sdk/libs/android/arm64-v8a/c++'
        if self.settings.os == "Android" and self.settings.arch == 'armv7':
            return '/firebase_cpp_sdk/libs/android/armeabi-v7a/c++'
        if self.settings.os == "Android" and self.settings.arch == 'x86_64':
            return '/firebase_cpp_sdk/libs/android/x86_64/c++'
        if self.settings.os == "Android" and self.settings.arch == 'x86':
            return '/firebase_cpp_sdk/libs/android/x86/c++'
        if self.settings.os == "Linux":
            return '/firebase_cpp_sdk/libs/linux/x86_64'

So it installs the linux x86_64 libs and it should be linking against those. I don't see why it wouldn't but as I said I have no way to check again right now. I added the compile command log with the compile command. As you'll see, the missing symbols are always at the interface with the stdlib. I think this should be easy enough to reproduce by just installing clang 9.0.0 and build on a debian system. But anyway I'll switch to the source version as it will be much safer in the long run.

Anyway, thanks for being so supportive. Feel free to close the issue if you feel this use case should not be supported. And now for the compile trace:

/home/circleci/.conan/data/llvm/9.0.0/company/stable/package/44fcf6b9a7fb86b2586303e3db40189d3b511830/bin/clang++  -DRELEASE -D__ARM_ARCH_6M__ -fcolor-diagnostics -fdata-sections -ffunction-sections -fno-math-errno -fno-strict-aliasing -fwrapv -march=native -mtune=native  -m64 -stdlib=libstdc++ -O3 -DNDEBUG  -fcolor-diagnostics -fuse-ld=lld -march=native -mtune=native CMakeFiles/flib-database_test_database_account_updater_mock.dir/test/test_database_account_updater_mock.cpp.o  -o bin/flib-database_test_database_account_updater_mock -L/home/circleci/.conan/data/bff/1.15.0.dev1+gfb1864bc/company/testing/package/d5f1d9fad1a6914bee0465d52846620d1f60d633/lib -Wl,-rpath,/home/circleci/.conan/data/bff/1.15.0.dev1+gfb1864bc/company/testing/package/d5f1d9fad1a6914bee0465d52846620d1f60d633/lib: lib/libflib-database.a lib/libflib-database.a lib/libflib-base.a /home/circleci/.conan/data/date/2.4.1/company/stable/package/22f05091b3ee7a8314e4dda687300cd648ceacab/lib/libtz.a /home/circleci/.conan/data/firebase-sdk/6.15.0+bloom2/company/stable/package/24647d9fe8ec489125dfbae4b3ebefaf7581674c/lib/libfirebase_firestore.a /home/circleci/.conan/data/firebase-sdk/6.15.0+bloom2/company/stable/package/24647d9fe8ec489125dfbae4b3ebefaf7581674c/lib/libfirebase_auth.a /home/circleci/.conan/data/firebase-sdk/6.15.0+bloom2/company/stable/package/24647d9fe8ec489125dfbae4b3ebefaf7581674c/lib/libfirebase_app.a -lbtw -lbad-test -lbad -lbell /home/circleci/.conan/data/fmt/5.3.0/bincrafters/stable/package/f983498779485cf195dc4850fb1e7b3943793e38/lib/libfmt.a -lpthread && cd /home/circleci/project/cmake-build-linux-x86_64-release-clang && /home/circleci/.conan/data/cmake_installer/3.15.3/conan/stable/package/44fcf6b9a7fb86b2586303e3db40189d3b511830/bin/cmake -D TEST_TARGET=flib-database_test_database_account_updater_mock -D TEST_EXECUTABLE=/home/circleci/project/cmake-build-linux-x86_64-release-clang/bin/flib-database_test_database_account_updater_mock -D TEST_EXECUTOR= -D TEST_WORKING_DIR=/home/circleci/project/cmake-build-linux-x86_64-release-clang -D TEST_SPEC= -D TEST_EXTRA_ARGS= -D TEST_PROPERTIES= -D TEST_PREFIX= -D TEST_SUFFIX= -D TEST_LIST=flib-database_test_database_account_updater_mock_TESTS -D CTEST_FILE=/home/circleci/project/cmake-build-linux-x86_64-release-clang/flib-database_test_database_account_updater_mock_tests-b858cb2.cmake -P /home/circleci/.conan/data/Catch2/2.11.1/catchorg/stable/package/5ab84d6acfe1f23c4fae0ab88f26e3a396351ac9/lib/cmake/Catch2/CatchAddTests.cmake

ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::is_registered(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_is_registered_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::Query::WhereEqualTo(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, firebase::firestore::FieldValue const&)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::is_registered(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_is_registered_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::CollectionReference::Document(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::create_user_data(flib::database::account const&, firebase::firestore::Transaction&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::create_user_data(flib::database::account const&, firebase::firestore::Transaction&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::create_user_data(flib::database::account const&, firebase::firestore::Transaction&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::create_user_data(flib::database::account const&, firebase::firestore::Transaction&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::create_user_data(flib::database::account const&, firebase::firestore::Transaction&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_email(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::Set(std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, firebase::firestore::FieldValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, firebase::firestore::FieldValue> > > const&, firebase::firestore::SetOptions const&)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_email(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::CollectionReference::Document(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::user()) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::CollectionReference::Document(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_name(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_name(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::Set(std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, firebase::firestore::FieldValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, firebase::firestore::FieldValue> > > const&, firebase::firestore::SetOptions const&)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_name(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::String(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_due_date(std::chrono::time_point<std::chrono::_V2::system_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::Set(std::unordered_map<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, firebase::firestore::FieldValue, std::hash<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::equal_to<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >, std::allocator<std::pair<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const, firebase::firestore::FieldValue> > > const&, firebase::firestore::SetOptions const&)

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::update_account_due_date(std::chrono::time_point<std::chrono::_V2::system_clock, std::chrono::duration<long, std::ratio<1l, 1000000000l> > > const&, std::shared_ptr<flib::database::account_update_handler> const&)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::CollectionReference::Document(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&) const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::pregnancy()) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::path[abi:cxx11]() const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::on_account_changed(firebase::firestore::DocumentSnapshot const&, firebase::firestore::Error)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::path[abi:cxx11]() const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::on_account_changed(firebase::firestore::DocumentSnapshot const&, firebase::firestore::Error)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::FieldValue::string_value[abi:cxx11]() const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::on_account_changed(firebase::firestore::DocumentSnapshot const&, firebase::firestore::Error)) in archive lib/libflib-database.a



ld.lld: error: undefined symbol: firebase::firestore::DocumentReference::path[abi:cxx11]() const

>>> referenced by backend_firebase.cpp

>>>               backend_firebase.cpp.o:(flib::database::backend_firebase::on_account_changed(firebase::firestore::DocumentSnapshot const&, firebase::firestore::Error)) in archive lib/libflib-database.a



ld.lld: error: too many errors emitted, stopping now (use -error-limit=0 to see all errors)

clang-9: error: linker command failed with exit code 1 (use -v to see invocation)

[chkuang-g]

According to this part of the doc, CXX11_ABI does not seems to be supported for prebuilt library. What if you add -D_GLIBCXX_USE_CXX11_ABI=0 parameter?

And if you really need ABI support, building from this open-source repo would be the way to go, as Patrick mentioned.

Hope this helps!