[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, 33 insertions, 7 deletions

diff --git a/lib/Lex/MacroInfo.cpp b/lib/Lex/MacroInfo.cpp
index 213e71132b..dc091f625b 100644
--- a/lib/Lex/MacroInfo.cpp
+++ b/lib/Lex/MacroInfo.cpp
@@ -108,14 +108,40 @@ bool MacroInfo::isIdenticalTo(const MacroInfo &Other, Preprocessor &PP) const {
   return true;
 }
 
-const MacroDirective *
+MacroDirective::DefInfo MacroDirective::getDefinition(bool AllowHidden) {
+  MacroDirective *MD = this;
+  SourceLocation UndefLoc;
+  Optional<bool> isPublic;
+  for (; MD; MD = MD->getPrevious()) {
+    if (!AllowHidden && MD->isHidden())
+      continue;
+
+    if (DefMacroDirective *DefMD = dyn_cast<DefMacroDirective>(MD))
+      return DefInfo(DefMD, UndefLoc,
+                     !isPublic.hasValue() || isPublic.getValue());
+
+    if (UndefMacroDirective *UndefMD = dyn_cast<UndefMacroDirective>(MD)) {
+      UndefLoc = UndefMD->getLocation();
+      continue;
+    }
+
+    VisibilityMacroDirective *VisMD = cast<VisibilityMacroDirective>(MD);
+    if (!isPublic.hasValue())
+      isPublic = VisMD->isPublic();
+  }
+
+  return DefInfo();
+}
+
+const MacroDirective::DefInfo
 MacroDirective::findDirectiveAtLoc(SourceLocation L, SourceManager &SM) const {
   assert(L.isValid() && "SourceLocation is invalid.");
-  for (const MacroDirective *MD = this; MD; MD = MD->Previous) {
-    if (MD->getLocation().isInvalid() ||  // For macros defined on the command line.
-        SM.isBeforeInTranslationUnit(MD->getLocation(), L))
-      return (MD->UndefLocation.isInvalid() ||
-              SM.isBeforeInTranslationUnit(L, MD->UndefLocation)) ? MD : NULL;
+  for (DefInfo Def = getDefinition(); Def; Def = Def.getPreviousDefinition()) {
+    if (Def.getLocation().isInvalid() ||  // For macros defined on the command line.
+        SM.isBeforeInTranslationUnit(Def.getLocation(), L))
+      return (!Def.isUndefined() ||
+              SM.isBeforeInTranslationUnit(L, Def.getUndefLocation()))
+                  ? Def : DefInfo();
   }
-  return NULL;
+  return DefInfo();
 }