Fix assertion when breaking string literals with tab characters.

Summary: Fixes http://llvm.org/PR19368

Reviewers: djasper, klimek

Reviewed By: klimek

CC: cfe-commits, klimek

Differential Revision: http://reviews.llvm.org/D3379

llvm-svn: 206295

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 35dc182a2d1..9311ca481c3 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -961,6 +961,12 @@ unsigned ContinuationIndenter::breakProtrudingToken(const FormatToken &Current,
         break;
       }
 
+      // When breaking before a tab character, it may be moved by a few columns,
+      // but will still be expanded to the next tab stop, so we don't save any
+      // columns.
+      if (NewRemainingTokenColumns == RemainingTokenColumns)
+        break;
+
       assert(NewRemainingTokenColumns < RemainingTokenColumns);
       if (!DryRun)
         Token->insertBreak(LineIndex, TailOffset, Split, Whitespaces);