Build LLVM [3.2, 3.6] with MinGW32 and MSYS

• Install MinGW
• Add C:/MinGW/bin, C:/MinGW/msys/1.0/bin to your path
• Download llvm source into llvm.src
• mkdir llvm.build
• If you also want to build clang/++ there are some changes that need to be made to the code (see here)
  • Open llvm-src/tools/clang/lib/Frontend/InitHeaderSearch.cpp
  • Go to around line 388
  • Check if the version of gcc that you are using with mingw has been added to the include search paths
  • If not add (for example if gcc is 4.7.2):

AddMinGW64CXXPaths(HSOpts.ResourceDir, "4.7.2");
AddMinGWCPlusPlusIncludePaths("c:/MinGW/lib/gcc", "mingw32", "4.7.2");

• If you're building LLVM < 3.3:
  • to fix a later issue with llvm-config, do this
• If you're building LLVM 3.6 and you use python 3 (bug #22976):
  • change line 829 of Makefile.rules to wrap the print arg with parens; i.e.

ECHOPATH := $(Verb)$(PYTHON) -u -c "import sys;print(' '.join(sys.argv[1:]))"

• Open the windows command line or msys (but not the msys bundled with msysgit, if you have it!) and cd into:
  • If building LLVM 3.3, cd into llvm.src; I could only get in-source build to work. Trying to do it out-of-source seems to work, except make install doesn't copy over the include files
  • for LLVM >= 3.4, out-of-source builds work, so cd into llvm.build
• Run sh ../llvm.src/configure --prefix=C:/LLVM/llvm-{version} --enable-pic --enable-optimized --disable-docs --enable-targets=x86,x86_64,cpp
  • (for in-source build, do sh configure ... instead)
  • --prefix MUST use forward slashes (otherwise you'll run into escape issues during make)
  • --disable-docs because "groff" isn't present in MinGW
  • --enable-targets because I only need x86; cpp is useful for seeing C++ API calls that produce a given IR using llc -O0 -march=cpp file.ir
• run make all; should have no problems
• open mingw's msys (not msysgit!) and run make install; should work; if you get a problem about it not being able to create Intrinsics.gen, it's because doing an out-of-source build doesn't work for some reason; do in-source instead
• LLVM should now be built. Add C:\LLVM\llvm-{version}\bin to your path.

At this point, you should be able to compile, link and run the Kaleidoscope example.