building a module. Prior to this change, the private header's content would
only be included if the header were included by another header in the same
module. If not (if the private header is only used by the .cc files of the
module, or is included from outside the module via -Wno-private-header),
a #include of that file would be silently ignored.
llvm-svn: 257222
This patch changes two things:
a) Allow a header to be part of multiple modules. The reasoning is that
in existing codebases that have a module-like build system, the same
headers might be used in several build targets. Simple reasons might be
that they defined different classes that are declared in the same
header. Supporting a header as a part of multiple modules will make the
transistion easier for those cases. A later step in clang can then
determine whether the two modules are actually compatible and can be
merged and error out appropriately. The later check is similar to what
needs to be done for template specializations anyway.
b) Allow modules to be stored in a directory tree separate from the
headers they describe.
Review: http://llvm-reviews.chandlerc.com/D1951
llvm-svn: 193151
Richard Smith