Clang's LLD hangs most of the time

[HolyBlackCat]

LLD (the clang's new linker) from package mingw-w64-x86_64-lld is pretty much unusable because it hangs on almost every run.

Official LLD binary from http://releases.llvm.org/download.html works correctly.

The hang can be reproduced with following commands:

echo -e '#include <iostream>\nint main() {std::cout << "Hello!\\n";}' >a.cpp
clang++ -fuse-ld=lld a.cpp

After this, ld.lld.exe (called by clang++) hangs indefinitely.

---

According to android/ndk#855 (also https://sourceforge.net/p/mingw-w64/bugs/774/) this seems to be caused by a bug in winpthreads that causes a deadlock...?

[mati865]

Would you like to try using this patch mstorsjo/llvm@winpthreads-workaround on top of MSYS2 mingw-w64-clang package?
If it works you can open PR with the fix.

[HolyBlackCat]

@mati865 I tried it today, but I'm on a relatively old PC, so building clang takes around 5 hours. (And the build just got interrupted at 80% accidentally, and I'm yet to figure out how to gracefully continue it without resetting progress.)

[mati865]

Makepkg has argument -e that will skip extraction and prepare(), you should also comment out cmake part from build().
I'll try to find some time to do the build.

[mati865]

That did the trick so here we go: #5247

CC @mstorsjo, probably he would like to hear back about this patch.