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Troubleshooting Build Issues

topolarity edited this page Jul 30, 2022 · 38 revisions

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.

Undefined references in liblldELF.a

Building with LLVM 14 has zlib as a new requirement.

If your system has static zlib then -DZIG_STATIC_ZLIB=ON needs to be specified to use it (e.g. cmake .. -DZIG_STATIC_ZLIB=ON).

Building stage2 and stage3

After successful building stage1, you build stage2 (or the same with stage3). If you get one of these:

LLD Link... ld.lld: error: unable to find library -lclangFrontendTool
ld.lld: error: unable to find library -lclangCodeGen
...

Then Zig was not able to find the LLVM libs. Add the path to the config header of the stage1 build to the build command, for example:

./stage2/bin/zig build -p stage3 -Denable-llvm -Dconfig_h=build/config.h

If you get this error (confirmed on Arch Linux):

ld.lld: error: undefined symbol: __libc_single_threaded

Then it is necessary to link the c_nonshared library. See #11137.

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_SHARED_LLVM:

cmake .. -DZIG_SHARED_LLVM=ON

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

Fedora also doesn't ship by default with the static libraries for lib stdc++. This will result in link errors for symbols like std::string. You can fix this by installing the following package: dnf install libstdc++-static.

Ubuntu/Debian

The LLVM repositories/packages are listed at https://apt.llvm.org/. The following packages that are not listed must be installed: liblld-14-dev, libclang-14-dev (as well as at least libllvm14 from the listed packages).

macOS

On macOS, you must force static linking of LLVM using -DZIG_STATIC_LLVM=on. The full invocation will then look like:

cmake .. -DCMAKE_PREFIX_PATH=$(brew --prefix llvm) -DZIG_STATIC_LLVM=on

After upgrading LLVM, it's often necessary to remove the CMake cache and build directories:

rm CMakeCache.txt
rm -rf CMakeFiles

Then try running the cmake command again.

High Memory Requirements

If you are failing at the last stage [99%] Building self-hosted component /PATHTOZIG/zig/build/zig1.o, make sure you have enough memory, as the process can take more than 10GiB of memory.

Related issue: zig0 takes too much RAM to build zig1.o The main development effort of Zig is focused on the self-hosted compiler, which solves this issue.

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