2 files changed, 17 insertions, 7 deletions
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp b/clang/lib/Lex/PPMacroExpansion.cpp
index 18348df0a39..11b4a0b3d8c 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -723,6 +723,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
   // heap allocations in the common case.
   SmallVector<Token, 64> ArgTokens;
   bool ContainsCodeCompletionTok = false;
+  bool FoundElidedComma = false;
 
   SourceLocation TooManyArgsLoc;
 
@@ -765,6 +766,10 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
         // If we found the ) token, the macro arg list is done.
         if (NumParens-- == 0) {
           MacroEnd = Tok.getLocation();
+          if (!ArgTokens.empty() &&
+              ArgTokens.back().commaAfterElided()) {
+            FoundElidedComma = true;
+          }
           break;
         }
       } else if (Tok.is(tok::l_paren)) {
@@ -909,7 +914,7 @@ MacroArgs *Preprocessor::ReadFunctionLikeMacroArgs(Token &MacroName,
       // then we have an empty "()" argument empty list.  This is fine, even if
       // the macro expects one argument (the argument is just empty).
       isVarargsElided = MI->isVariadic();
-    } else if (MI->isVariadic() &&
+    } else if ((FoundElidedComma || MI->isVariadic()) &&
                (NumActuals+1 == MinArgsExpected ||  // A(x, ...) -> A(X)
                 (NumActuals == 0 && MinArgsExpected == 2))) {// A(x,...) -> A()
       // Varargs where the named vararg parameter is missing: OK as extension.
diff --git a/clang/lib/Lex/TokenLexer.cpp b/clang/lib/Lex/TokenLexer.cpp
index ed2b8cdabd1..3f66b7f9b76 100644
--- a/clang/lib/Lex/TokenLexer.cpp
+++ b/clang/lib/Lex/TokenLexer.cpp
@@ -154,12 +154,17 @@ bool TokenLexer::MaybeRemoveCommaBeforeVaArgs(
   // Remove the comma.
   ResultToks.pop_back();
 
-  // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"),
-  // then removal of the comma should produce a placemarker token (in C99
-  // terms) which we model by popping off the previous ##, giving us a plain
-  // "X" when __VA_ARGS__ is empty.
-  if (!ResultToks.empty() && ResultToks.back().is(tok::hashhash))
-    ResultToks.pop_back();
+  if (!ResultToks.empty()) {
+    // If the comma was right after another paste (e.g. "X##,##__VA_ARGS__"),
+    // then removal of the comma should produce a placemarker token (in C99
+    // terms) which we model by popping off the previous ##, giving us a plain
+    // "X" when __VA_ARGS__ is empty.
+    if (ResultToks.back().is(tok::hashhash))
+      ResultToks.pop_back();
+
+    // Remember that this comma was elided.
+    ResultToks.back().setFlag(Token::CommaAfterElided);
+  }
 
   // Never add a space, even if the comma, ##, or arg had a space.
   NextTokGetsSpace = false;