llvm-project

c4dc21ec - [Clang][Modules] Emit C++20 BMIs to working directory with -fmodule-output (#174560)

[Clang][Modules] Emit C++20 BMIs to working directory with -fmodule-output (#174560) Close #173689. When -fmodule-output is specified without an explicit path, Clang currently emits the generated .pcm next to the source file. This contradicts the documentation and breaks out-of-tree builds. This patch updates the fallback behavior to emit the BMI in the working directory, instead of the source file directory. Driver tests are updated accordingly. Explicit -fmodule-output=PATH behavior is unchanged.