[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, 1 insertions, 1 deletions

diff --git a/clang/lib/Lex/Pragma.cpp b/clang/lib/Lex/Pragma.cpp
index a5f1a62a708..6a8b0a6bd31 100644
--- a/clang/lib/Lex/Pragma.cpp
+++ b/clang/lib/Lex/Pragma.cpp
@@ -605,7 +605,7 @@ void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
     if (MacroToReInstall) {
       // Reinstall the previously pushed macro.
       appendDefMacroDirective(IdentInfo, MacroToReInstall, MessageLoc,
-                              /*isImported=*/false);
+                              /*isImported=*/false, /*Overrides*/None);
     }
 
     // Pop PragmaPushMacroInfo stack.