Fixed a problem with #pragma push_macro/pop_macro implementation.

Summary:
The problem was with the following sequence:
  #pragma push_macro("long")
  #undef long
  #pragma pop_macro("long")
in case when "long" didn't represent a macro.
Fixed crash and removed code duplication for #undef/pop_macro case. Added regression tests.

Reviewers: doug.gregor, klimek

Reviewed By: doug.gregor

CC: cfe-commits, chapuni

Differential Revision: http://llvm-reviews.chandlerc.com/D31

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162845 91177308-0d34-0410-b5e6-96231b3b80d8

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){