The bringup hack, again, is to just process the module source files as a
TranslationUnit if the module doesn't accurately represent the original
source. Currently this happens if the module is not empty, or if it imports
/anything/, since we don't actually serialize anything yet.
This also cleans up the decl/type serialization skeleton a bit.
Swift SVN r5238
Like Clang, ModuleFile contains state about reading the serialized module,
while SerializedModuleLoader takes the place of ASTReader in tracking
cross-module data. I'm diverging from Clang's architecture a bit here by
pushing the actual deserialization logic into ModuleFile.
No functionality change.
Swift SVN r5174