[modules] Substantially improve handling of #undef:

 * Track override set across module load and save
 * Track originating module to allow proper re-export of #undef
 * Make override set properly transitive when it picks up a #undef

This fixes nearly all of the remaining macro issues with self-host.

llvm-svn: 213922

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/test/Modules/macro-reexport/module.modulemap b/clang/test/Modules/macro-reexport/module.modulemap
index 21585b692e3..896bda041c3 100644
--- a/clang/test/Modules/macro-reexport/module.modulemap
+++ b/clang/test/Modules/macro-reexport/module.modulemap
@@ -13,3 +13,11 @@ module d {
   module d1 { header "d1.h" export * }
   module d2 { header "d2.h" export * }
 }
+module e {
+  module e1 { header "e1.h" export * }
+  module e2 { header "e2.h" export * }
+}
+module f {
+  module f1 { header "f1.h" export * }
+  module f2 { header "f2.h" export * }
+}