This addresses a FIXME in ASTReader.
Modules were already re-exported for Preprocessor, but not for Sema.
The result was that, with -fmodules-local-submodule-visibility, all AST
nodes belonging to a module that was loaded in a premable where not
accesible from the main part of the file and a diagnostic recommending
importing those modules would be generated.
Differential Revision: https://reviews.llvm.org/D86069
the one in the current compiler invocation. If they differ reject the PCH.
This protects against the badness occurring from getting modules loaded from different module caches (see crashes).
rdar://19889860
llvm-svn: 229909
Adam Czachorowski