When we expect two arguments but have zero, make sure to add

two empty arguments.  Also, add an assert so that this bug
manifests as an assertion failure, not a valgrind problem.

This fixes rdar://6880648 - [cpp] crash in ArgNeedsPreexpansion


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@71616 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/Lex/MacroArgs.cpp b/lib/Lex/MacroArgs.cpp
index 2646a61e51..cba69b7d79 100644
--- a/lib/Lex/MacroArgs.cpp
+++ b/lib/Lex/MacroArgs.cpp
@@ -72,6 +72,7 @@ const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
     if (Result->is(tok::eof))
       --Arg;
   }
+  assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");
   return Result;
 }