We used to have a flag to enable module maps, and two more flags to enable
implicit module maps. This is all redundant; we don't need any flag for
enabling module maps in the abstract, and we don't usually have -fno- flags for
-cc1. We now have just a single flag, -fimplicit-module-maps, that enables
implicitly searching the file system for module map files and loading them.
The driver interface is unchanged for now. We should probably rename
-fmodule-maps to -fimplicit-module-maps at some point.
llvm-svn: 239789
Instead, mark the module as unavailable so that clang errors as soon as
someone tries to build this module.
This works towards the long-term goal of not stat'ing the header files at all
while reading the module map and instead read them only when the module is
being built (there is a corresponding FIXME in parseHeaderDecl()). However, it
seems non-trivial to get there and this unblock us and moves us into the right
direction.
Also changed the implementation to reuse the same DiagnosticsEngine.
llvm-svn: 197485
Richard Smith