libclang has no registered targets after r371787

[llvmbot]

Bugzilla Link	45809
Resolution	FIXED
Resolved on	May 07, 2020 11:12
Version	10.0
OS	Windows NT
Blocks	#44654
Reporter	LLVM Bugzilla Contributor
CC	@jkorous-apple,@zygoloid,@tstellar
Fixed by commit(s)	02b3033 db810b6

Extended Description

After r371787 [0], when Rust's bindgen uses libclang, it fails with "no targets are registered" [1].

This only happens when we build LLVM with -DLLVM_LINK_LLVM_DYLIB=ON.

jkorous: I'm not clear on why LLVMSupport was added to libclang's CMakeLists.txt. If I remove that line, the code still compiles, and this bug goes away. I'm not familiar with this part of the code though -- do you have any idea what might be going on?

[0] https://reviews.llvm.org/rL371787
[1]

llvm-project/llvm/lib/Support/TargetRegistry.cpp

Line 66 in 2946cd7

Error = "Unable to find target for this triple (no targets are registered)";

[jkorous-apple]

Hi David,

You're right - the Support dependency was already there so the line I added is a duplicate.
I have no idea how it is related to backend targets but seems like there's no reason to have the line there.
Let me just test the patch - I'll let you know when it lands (later today?).

Thanks,
Jan

[jkorous-apple]

https://reviews.llvm.org/D79451

[jkorous-apple]

Landed in 02b3033

[tstellar]

Merged: db810b6