lld out of memory

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1

Hi,
I am seeing an LLVM build failure with recent LLD on x86 like:

[…]
lib/libLLVMCodeGen.a lib/libLLVMBitWriter.a lib/libLLVMScalarOpts.a lib/libLLVMAgg
ressiveInstCombine.a lib/libLLVMInstCombine.a lib/libLLVMTransformUtils.a lib/libLLVMDebugInfoDWARF.a lib/lib
LLVMMCDisassembler.a lib/libLLVMExecutionEngine.a lib/libLLVMTarget.a lib/libLLVMAnalysis.a lib/libLLVMProfil
eData.a lib/libLLVMRuntimeDyld.a lib/libLLVMObject.a lib/libLLVMMCParser.a lib/libLLVMMC.a lib/libLLVMDebugI
nfoCodeView.a lib/libLLVMDebugInfoMSF.a lib/libLLVMBitReader.a lib/libLLVMCore.a lib/libLLVMRemarks.a lib/li
bLLVMBitstreamReader.a lib/libLLVMTextAPI.a lib/libLLVMBinaryFormat.a lib/libLLVMSupport.a /usr/lib64/libz.so
-lrt -ldl -ltinfo -lpthread -lm lib/libLLVMDemangle.a && :
LLVM ERROR: out of memory
Stack dump:
0. Program arguments: /home/usr4/c74014i/opt/clang/stable/bin/ld.lld @/tmp/response-5051e9.txt
LLVM ERROR: out of memory
clang-11: error: unable to execute command: Aborted
clang-11: error: linker command failed due to signal (use -v to see invocation)
[32/492] Building CXX object tools/llvm-cov/CMakeFiles/llvm-cov.dir/gcov.cpp.o

As reported on Discord, switching back to ld works around this issue.
On my system a process gets a 6 GB of memory max can be used, and I use
ninja -j16.

2

I take it back it is -j8.

3

See here you can specify the number of concurrent link jobs
https://llvm.org/docs/CMake.html#llvm-specific-variables with
LLVM_PARALLEL_LINK_JOBS. Increasing swap space is also an option, and
I have had to do this on a system with only 8gb of memory. As to why
it work with ld.gold/bfd and not lld I couldn't say, this seems
contrary to what most people report which is that lld uses less memory
and is faster. Usually this list recommends lld, so I'm surprised.
Also BUILD_SHARED_LIBS should be helpful.

4

Alex et al.,

For me, setting explicitly LLVM_PARALLEL_LINK_JOBS to 2 did not help, but

BUILD_SHARED_LIBS=ON

did the trick! Thanks!