Jussi Pakkanen via SG15 <sg15_at_[hidden]> writes:

> The build system would create a new directory for each top level
> target (Meson and CMake already do this) and would guarantee that each
> compiler invocation would have a flag, say,
> --target-private-dir=path/to/dir which would be the same for each
> target (exe, static lib, shared lib etc). The compiler would then be
> allowed to store whatever information it wants in there.

This was probably brought up during the discussion, but just in
case: Naturally, the build system will be running multiple compiler
instances that share such a private directory in parallel. Which
means that for anything shared there will need to be filesystem-
based locking/synchronization. It is my understanding this aspect
made Clang's implicit modules unworkable.