[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

2 files changed, 17 insertions, 12 deletions

diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index d7ed0b4859e..da50bba598f 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -64,25 +64,30 @@ MacroInfo *Preprocessor::AllocateDeserializedMacroInfo(SourceLocation L,
 
 DefMacroDirective *
 Preprocessor::AllocateDefMacroDirective(MacroInfo *MI, SourceLocation Loc,
-                                        bool isImported) {
-  DefMacroDirective *MD = BP.Allocate<DefMacroDirective>();
-  new (MD) DefMacroDirective(MI, Loc, isImported);
-  return MD;
+                                        unsigned ImportedFromModuleID,
+                                        ArrayRef<unsigned> Overrides) {
+  unsigned NumExtra = (ImportedFromModuleID ? 1 : 0) + Overrides.size();
+  return new (BP.Allocate(sizeof(DefMacroDirective) +
+                              sizeof(unsigned) * NumExtra,
+                          llvm::alignOf<DefMacroDirective>()))
+      DefMacroDirective(MI, Loc, ImportedFromModuleID, Overrides);
 }
 
 UndefMacroDirective *
-Preprocessor::AllocateUndefMacroDirective(SourceLocation UndefLoc) {
-  UndefMacroDirective *MD = BP.Allocate<UndefMacroDirective>();
-  new (MD) UndefMacroDirective(UndefLoc);
-  return MD;
+Preprocessor::AllocateUndefMacroDirective(SourceLocation UndefLoc,
+                                          unsigned ImportedFromModuleID,
+                                          ArrayRef<unsigned> Overrides) {
+  unsigned NumExtra = (ImportedFromModuleID ? 1 : 0) + Overrides.size();
+  return new (BP.Allocate(sizeof(UndefMacroDirective) +
+                              sizeof(unsigned) * NumExtra,
+                          llvm::alignOf<UndefMacroDirective>()))
+      UndefMacroDirective(UndefLoc, ImportedFromModuleID, Overrides);
 }
 
 VisibilityMacroDirective *
 Preprocessor::AllocateVisibilityMacroDirective(SourceLocation Loc,
                                                bool isPublic) {
-  VisibilityMacroDirective *MD = BP.Allocate<VisibilityMacroDirective>();
-  new (MD) VisibilityMacroDirective(Loc, isPublic);
-  return MD;
+  return new (BP) VisibilityMacroDirective(Loc, isPublic);
 }
 
 /// \brief Clean up a MacroInfo that was allocated but not used due to an
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.