Vendor import of clang r114020 (from the release_28 branch):

http://llvm.org/svn/llvm-project/cfe/branches/release_28@114020

Approved by:	rpaulo (mentor)

1 files changed, 15 insertions, 3 deletions

diff --git a/lib/Lex/TokenLexer.cpp b/lib/Lex/TokenLexer.cpp
index 56bb073..94719b0 100644
--- a/lib/Lex/TokenLexer.cpp
+++ b/lib/Lex/TokenLexer.cpp
@@ -268,6 +268,13 @@ void TokenLexer::ExpandFunctionArguments() {
       // Remove the paste operator, report use of the extension.
       PP.Diag(ResultToks.back().getLocation(), diag::ext_paste_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();
     }
     continue;
   }
@@ -478,7 +485,7 @@ bool TokenLexer::PasteTokens(Token &Tok) {
           return true;
         }
 
-        // Do not emit the warning when preprocessing assembler code.
+        // Do not emit the error when preprocessing assembler code.
         if (!PP.getLangOptions().AsmPreprocessor) {
           // Explicitly convert the token location to have proper instantiation
           // information so that the user knows where it came from.
@@ -486,8 +493,13 @@ bool TokenLexer::PasteTokens(Token &Tok) {
           SourceLocation Loc =
             SM.createInstantiationLoc(PasteOpLoc, InstantiateLocStart,
                                       InstantiateLocEnd, 2);
-          PP.Diag(Loc, diag::err_pp_bad_paste)
-            << std::string(Buffer.begin(), Buffer.end());
+          // If we're in microsoft extensions mode, downgrade this from a hard
+          // error to a warning that defaults to an error.  This allows
+          // disabling it.
+          PP.Diag(Loc,
+                  PP.getLangOptions().Microsoft ? diag::err_pp_bad_paste_ms 
+                                                : diag::err_pp_bad_paste)
+            << Buffer.str();
         }
 
         // Do not consume the RHS.