When Clang encounters `@import M.Private` during implicit build, it precompiles module `M` and looks through its submodules. If the `Private` submodule is not found, Clang assumes `@import M_Private`. In the dependency scanner, we don't capture the dependency on `M`, since it's not imported. It's an affecting module, though: compilation of the import statement will fail when implicit modules are disabled and `M` is not precompiled and explicitly provided. This patch fixes that.
Depends on D132430.
Reviewed By: benlangmuir
Differential Revision: https://reviews.llvm.org/D132502
In case `@import Foo.Private` fails because the submodule doesn't exist,
look for `Foo_Private` (if available) and build/load that module
instead. In that process emit a warning and tell the user about the
assumption.
The intention here is to assist all existing private modules owners
(in ObjC and Swift) to migrate to the new `Foo_Private` syntax.
rdar://problem/36023940
llvm-svn: 321342
Jan Svoboda