[Preprocessor/Modules] Separate the macro directives kinds into their own MacroDirective's subclasses.

For each macro directive (define, undefine, visibility) have a separate object that gets chained
to the macro directive history. This has several benefits:

-No need to mutate a MacroDirective when there is a undefine/visibility directive. Stuff like
 PPMutationListener become unnecessary.
-No need to keep extra source locations for the undef/visibility locations for the define directive object
 (which is the majority of the directives)
-Much easier to hide/unhide a section in the macro directive history.
-Easier to track the effects of the directives across different submodules.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178037 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 7 deletions

diff --git a/lib/Lex/Pragma.cpp b/lib/Lex/Pragma.cpp
index 2094dd1e1c..95e8a8ca8f 100644
--- a/lib/Lex/Pragma.cpp
+++ b/lib/Lex/Pragma.cpp
@@ -703,9 +703,10 @@ void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
   if (iter != PragmaPushMacroInfo.end()) {
     // Forget the MacroInfo currently associated with IdentInfo.
     if (MacroDirective *CurrentMD = getMacroDirective(IdentInfo)) {
-      if (CurrentMD->getInfo()->isWarnIfUnused())
-        WarnUnusedMacroLocs.erase(CurrentMD->getInfo()->getDefinitionLoc());
-      UndefineMacro(IdentInfo, CurrentMD, MessageLoc);
+      MacroInfo *MI = CurrentMD->getMacroInfo();
+      if (MI->isWarnIfUnused())
+        WarnUnusedMacroLocs.erase(MI->getDefinitionLoc());
+      appendMacroDirective(IdentInfo, AllocateUndefMacroDirective(MessageLoc));
     }
 
     // Get the MacroInfo we want to reinstall.
@@ -713,10 +714,8 @@ void Preprocessor::HandlePragmaPopMacro(Token &PopMacroTok) {
 
     if (MacroToReInstall) {
       // Reinstall the previously pushed macro.
-      setMacroDirective(IdentInfo, MacroToReInstall, MessageLoc,
-                        /*isImported=*/false);
-    } else if (IdentInfo->hasMacroDefinition()) {
-      clearMacroInfo(IdentInfo);
+      appendDefMacroDirective(IdentInfo, MacroToReInstall, MessageLoc,
+                              /*isImported=*/false);
     }
 
     // Pop PragmaPushMacroInfo stack.