1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Lex/PPMacroExpansion.cpp b/lib/Lex/PPMacroExpansion.cpp
index 936b37009c..3f27236cac 100644
--- a/lib/Lex/PPMacroExpansion.cpp
+++ b/lib/Lex/PPMacroExpansion.cpp
@@ -57,6 +57,15 @@ void Preprocessor::setMacroInfo(IdentifierInfo *II, MacroInfo *MI,
     II->setChangedSinceDeserialization();
 }
 
+/// \brief Undefine a macro for this identifier.
+void Preprocessor::clearMacroInfo(IdentifierInfo *II) {
+  assert(II->hasMacroDefinition() && "Macro is not defined!");
+  assert(Macros[II]->getUndefLoc().isValid() && "Macro is still defined!");
+  II->setHasMacroDefinition(false);
+  if (II->isFromAST())
+    II->setChangedSinceDeserialization();
+}
+
 /// RegisterBuiltinMacro - Register the specified identifier in the identifier
 /// table and mark it as a builtin macro to be expanded.
 static IdentifierInfo *RegisterBuiltinMacro(Preprocessor &PP, const char *Name){