Link time error when building LLVM
Link time error with ld
Lately, LLVM compilation kept failing with SIGKILL at link-time on my machine with 16 GB RAM. This only happened when I’m building LLVM with Debug info.
# Configure to build in `Debug` mode (results in SIGKILL)
$ cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug
$ cmake --build build
# Configure to build in `Release` mode (build success)
$ cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Release
$ cmake --build build
ERROR MESSAGE (SIGKILL):
[62/191] Linking CXX executable bin/llvm-debuginfo-analyzer
FAILED: bin/llvm-debuginfo-analyzer
: && /usr/bin/c++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -g -Wl,-rpath-link,/home/joe/repos/llvm-project/build/./lib tools/llvm-debuginfo-analyzer/CMakeFiles/llvm-debuginfo-analyzer.dir/llvm-debuginfo-analyzer.cpp.o tools/llvm-debuginfo-analyzer/CMakeFiles/llvm-debuginfo-analyzer.dir/Options.cpp.o -o bin/llvm-debuginfo-analyzer -Wl,-rpath,"\$ORIGIN/../lib" lib/libLLVMAArch64Desc.a lib/libLLVMAMDGPUDesc.a lib/libLLVMARMDesc.a lib/libLLVMAVRDesc.a lib/libLLVMBPFDesc.a lib/libLLVMHexagonDesc.a lib/libLLVMLanaiDesc.a lib/libLLVMMipsDesc.a lib/libLLVMMSP430Desc.a lib/libLLVMNVPTXDesc.a lib/libLLVMPowerPCDesc.a lib/libLLVMRISCVDesc.a lib/libLLVMSparcDesc.a lib/libLLVMSystemZDesc.a lib/libLLVMVEDesc.a lib/libLLVMWebAssemblyDesc.a lib/libLLVMX86Desc.a lib/libLLVMXCoreDesc.a lib/libLLVMAArch64Info.a lib/libLLVMAMDGPUInfo.a lib/libLLVMARMInfo.a lib/libLLVMAVRInfo.a lib/libLLVMBPFInfo.a lib/libLLVMHexagonInfo.a lib/libLLVMLanaiInfo.a lib/libLLVMMipsInfo.a lib/libLLVMMSP430Info.a lib/libLLVMNVPTXInfo.a lib/libLLVMPowerPCInfo.a lib/libLLVMRISCVInfo.a lib/libLLVMSparcInfo.a lib/libLLVMSystemZInfo.a lib/libLLVMVEInfo.a lib/libLLVMWebAssemblyInfo.a lib/libLLVMX86Info.a lib/libLLVMXCoreInfo.a lib/libLLVMAArch64Disassembler.a lib/libLLVMAMDGPUDisassembler.a lib/libLLVMARMDisassembler.a lib/libLLVMAVRDisassembler.a lib/libLLVMBPFDisassembler.a lib/libLLVMHexagonDisassembler.a lib/libLLVMLanaiDisassembler.a lib/libLLVMMipsDisassembler.a lib/libLLVMMSP430Disassembler.a lib/libLLVMPowerPCDisassembler.a lib/libLLVMRISCVDisassembler.a lib/libLLVMSparcDisassembler.a lib/libLLVMSystemZDisassembler.a lib/libLLVMVEDisassembler.a lib/libLLVMWebAssemblyDisassembler.a lib/libLLVMX86Disassembler.a lib/libLLVMXCoreDisassembler.a lib/libLLVMBinaryFormat.a lib/libLLVMDebugInfoLogicalView.a lib/libLLVMDebugInfoCodeView.a lib/libLLVMDebugInfoDWARF.a lib/libLLVMDebugInfoPDB.a lib/libLLVMMC.a lib/libLLVMMCDisassembler.a lib/libLLVMObject.a lib/libLLVMSupport.a lib/libLLVMAArch64Desc.a lib/libLLVMAArch64Info.a lib/libLLVMAArch64Utils.a lib/libLLVMAMDGPUDesc.a lib/libLLVMAMDGPUInfo.a lib/libLLVMAMDGPUUtils.a lib/libLLVMARMDesc.a lib/libLLVMARMInfo.a lib/libLLVMARMUtils.a lib/libLLVMAVRInfo.a lib/libLLVMBPFInfo.a lib/libLLVMHexagonDesc.a lib/libLLVMHexagonInfo.a lib/libLLVMLanaiDesc.a lib/libLLVMLanaiInfo.a lib/libLLVMMipsInfo.a lib/libLLVMMSP430Info.a lib/libLLVMPowerPCInfo.a lib/libLLVMRISCVDesc.a lib/libLLVMRISCVInfo.a lib/libLLVMSparcInfo.a lib/libLLVMSystemZDesc.a lib/libLLVMSystemZInfo.a lib/libLLVMVEInfo.a lib/libLLVMWebAssemblyDesc.a lib/libLLVMWebAssemblyInfo.a lib/libLLVMWebAssemblyUtils.a lib/libLLVMCodeGen.a lib/libLLVMBitWriter.a lib/libLLVMObjCARCOpts.a lib/libLLVMScalarOpts.a lib/libLLVMAggressiveInstCombine.a lib/libLLVMInstCombine.a lib/libLLVMTarget.a lib/libLLVMTransformUtils.a lib/libLLVMAnalysis.a lib/libLLVMProfileData.a lib/libLLVMSymbolize.a lib/libLLVMDebugInfoPDB.a lib/libLLVMDebugInfoMSF.a lib/libLLVMX86Info.a lib/libLLVMXCoreInfo.a lib/libLLVMMCDisassembler.a lib/libLLVMDebugInfoDWARF.a lib/libLLVMObject.a lib/libLLVMIRReader.a lib/libLLVMBitReader.a lib/libLLVMAsmParser.a lib/libLLVMCore.a lib/libLLVMRemarks.a lib/libLLVMBitstreamReader.a lib/libLLVMMCParser.a lib/libLLVMMC.a lib/libLLVMDebugInfoCodeView.a lib/libLLVMTextAPI.a lib/libLLVMBinaryFormat.a lib/libLLVMSupport.a -lrt -ldl -lm /usr/lib/x86_64-linux-gnu/libz.so /usr/lib/x86_64-linux-gnu/libtinfo.so lib/libLLVMDemangle.a && :
collect2: fatal error: ld terminated with signal 9 [Killed]
compilation terminated.
[79/191] Linking CXX executable bin/llvm-cfi-verify
ninja: build stopped: subcommand failed.
My suspected cause is Out of Memory.
Gold Linker
I had previously heard some people bash ld for consuming too much RAM when handling debug info. So I tried using gold instead.
# Configure to build in Debug mode, using `gold`
$ cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DLLVM_USE_LINKER=gold
$ cmake --build build
After making loud noises for an hour, my computer just rebooted itself (and of course the build failed)..
LLD linker
This page from the gentoo linux wiki mentions that gold isn’t maintained actively, and kindly recommends to use the lld linker instead.
# Configure to build in Debug mode, using `lld` linker
$ cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DLLVM_ENABLE_LLD=ON
I got the following error:
CMake Error at cmake/modules/HandleLLVMOptions.cmake:309 (message):
Host compiler does not support '-fuse-ld=lld'
Call Stack (most recent call first):
CMakeLists.txt:875 (include)
My system’s default C/C++ toolchain is GCC, which doesn’t support using LLD.
I had to switch my system’s default C/C++ toolchain to Clang in order to use -DLLVM_ENABLE_LLD=ON.
I found a stackoverflow Q&A with instructions on how to do so.
Eventually, I didn’t try this route. I wanted a solution that involves no changes to my system’s default settings.
-DBUILD_SHARED_LIBS=ON to the Rescue
I read through relevant discussions & docs online:
- https://lists.llvm.org/pipermail/llvm-dev/2018-September/126305.html
- https://groups.google.com/g/llvm-dev/c/hCd4wAigCMo?pli=1
- https://llvm.org/docs/GettingStarted.html#common-problems
-DBUILD_SHARED_LIBS=ON is enough to get a successful Debug build
(on my system, for now).
$ cmake -S llvm -B build -G Ninja -DCMAKE_BUILD_TYPE=Debug -DBUILD_SHARED_LIBS=ON
$ cmake --build build