build-llvm-3-4-2.sh

wget https://releases.llvm.org/3.4.2/llvm-3.4.2.src.tar.gz
tar -xzf llvm-3.4.2.src.tar.gz
cd llvm-3.4.2.src

# comment out memory sanitizer checks
# see https://stackoverflow.com/questions/48188796/clang-4-0-fails-to-build-clang-3-42-on-ubuntu-17-04
sed -i '' -e 's/__msan_unpoison/\/\/__msan_unpoison/' ./lib/Target/X86/X86JITInfo.cpp
sed -i '' -e 's/__msan_allocated_memory/\/\/__msan_allocated_memory/' lib/Support/Allocator.cpp
sed -i '' -e 's/__msan_unpoison/\/\/__msan_unpoison/' lib/Support/Compression.cpp
mkdir build && cd build && cmake ..
make