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Troubleshooting Build Issues

Tau edited this page Jun 13, 2021 · 38 revisions

Troubleshooting

Dual-Abi Linking

If you get one of these:

undefined reference to `_ZNK4llvm17SubtargetFeatures9getStringB5cxx11Ev'
undefined reference to `llvm::SubtargetFeatures::getString() const'

This is because of C++'s Dual ABI. Most likely LLVM was compiled with one compiler while Zig was compiled with a different one, for example GCC vs clang.

LLVM, Clang, and Zig must all be compiled with the same C++ compiler.

Arch Linux, Gentoo, Fedora 32+

The Clang packages in these distributions do not contain static libraries, which Zig tries to use by default. Instead, one should link against the shared lib libclang-cpp.so.

For building stage1, set ZIG_PREFER_CLANG_CPP_DYLIB:

cmake .. -DZIG_PREFER_CLANG_CPP_DYLIB=true

For building stage2, pass -Dstatic-llvm=false to Zig.

Gentoo

If you get the message : CommandLine Error: Option 'mc-relax-all' registered more than once!, you're affected by the issue discussed in https://reviews.llvm.org/D75579. The fix has not (yet?) been included in clang 10.0.1. As a workaround, you can build clang with the line add_clang_subdirectory(handle-llvm) removed from clang/tools/clang-fuzzer/CMakeLists.txt.

Additionally, you'll need lld's .a and .h files, which aren't installed by Gentoo's lld ebuild, so you'll need to modify your lld ebuild file to not delete them.

Ubuntu/Debian

The LLVM repositories/packages are listed at https://apt.llvm.org/. The following packages that are not listed must be installed: liblld-12-dev, libclang-12-dev (as well as at least libllvm12 from the listed packages).

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