I have built LLVM/clang from trunk for many years. Since a few weeks back that is no longer possible. I end up with this error:
-- LLVM host triple: x86_64-unknown-linux-gnu
-- LLVM default target triple: x86_64-unknown-linux-gnu
-- Using libunwind testing configuration: /big/llvm/libunwind/test/configs/llvm-libunwind-shared.cfg.in
CMake Error at /big/llvm/libunwind/src/CMakeLists.txt:104 (message):
Compiler doesn't support generation of unwind tables if exception support
is disabled. Building libunwind DSO with runtime dependency on C++ ABI
library is not supported.
I have tried to start from scratch with a clean build directory but I end up with the same error.
I have tried to compile with both gcc and clang with the same result.
The cmake line I used (in my last attempt was):
cmake -S llvm -B build -G Ninja -Wno-dev -DCMAKE_INSTALL_PREFIX=/mypreifx -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++ -DLLVM_ENABLE_PROJECTS='clang;clang-tools-extra;lld;lldb' -DLLVM_ENABLE_Z3_SOLVER=ON -DLLVM_ENABLE_RUNTIMES=all -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_BINDINGS=OFF -DLLVM_BUILD_TESTS=OFF -DLLVM_TARGETS_TO_BUILD=X86
Any hints on how to solve this?
-DLLVM_ENABLE_RUNTIMES=all is probably more than you want. Do you need to build libunwind and llvm-libc?
I have not included
libc in the list passed to
libunwind know to be broken in current trunk?
That’s true. But you enabled all runtimes including libunwind and llvm-libc.
Replaces all runtimes with only
compiler-rt but this seems to be a non-working combination as well:
/usr/bin/ld: compiler-rt/lib/hwasan/CMakeFiles/RTHwasanAliases_dynamic.x86_64.dir/hwasan_linux.cpp.o: relocation R_X86_64_TPOFF32 against symbol `__hwasan_tls' can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: failed to set dynamic section sizes: bad value
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
The last time I tried to build I saw the following warning flash by:
[9/13] Performing configure step for 'runtimes'
Not searching for unused variables given on the command line.
CMake Warning at /big/llvm/llvm/cmake/modules/HandleLLVMOptions.cmake:281 (message):
-fPIC is not supported.
Call Stack (most recent call first):
I got it working by explicitly adding
-DBUILD_SHARED_LIBS=OFF to the cmake command line.