These changes have been merged up into Jakob's original revision, so closing this one now.

Upon building the 32 bit DLL, I discovered the way I was detecting host architecture was wrong. Checking LLVM_HOST_TRIPLE works on both 64 and 32 bit builds, but let me know if there's a better way of figuring this stuff out from cmake.

Upon further testing, I can verify that the generated DLL appears to work.

I work with Jakob on the afore mentioned self hosting language frontend. Would like to see this get in, what else is needed? I just built the version that Jakob recently updated, and it produces a LLVM-C.dll and lib file with what looks like the right functions (when looked at with a dependency walker); not sure how best to test it beyond that. Let me know what needs to be done and I'll try my best to do it.

I was just checking everything was working by running this batch file in the test folder, and once I was happy I checked in a Linux VM.

In D30356#689600, @NickBarnes wrote:

I am willing to hack on this llvm-c-test, but the LLVM project pages are unclear about the pre-requisites for testing. It says that I need GnuWin32, but does not specify which GnuWin32 packages. There are about 100....

In D30356#688421, @NickBarnes wrote:

Sorry to be off the case for so long; I've been working on another project. Great to see that this is being taken up. The compiler I first wrote this for is now functionally complete, using (broadly) the same patch I originally submitted here on top of 3.9.1. What can I usefully do now that I'm back on this?

I didn't know how to not make clang-format chew everything up, so I've tried to match the surrounding format as much as possible. I'm not super knowledgeable on the EH stuff, or LLVM's test suite, so it's very likely that I've made a mistake somewhere in adding to echo.cpp, but everything seems to work.