[clang-format] Handle NSString literals by merging tokens.

Summary:
This fixes a few outstanding bugs:
  * incorrect breaking of NSString literals containing double-width characters;
  * inconsistent formatting of ObjC dictionary literals containing NSString
    literals;
  * AlwaysBreakBeforeMultilineStrings ignoring implicitly-concatenated NSString
    literals.

Reviewers: djasper

Reviewed By: djasper

Subscribers: klimek, cfe-commits

Differential Revision: https://reviews.llvm.org/D31706

llvm-svn: 299927

1 files changed, 2 insertions, 9 deletions

diff --git a/clang/lib/Format/BreakableToken.cpp b/clang/lib/Format/BreakableToken.cpp
index b42e4aee505..c97486e4e4a 100644
--- a/clang/lib/Format/BreakableToken.cpp
+++ b/clang/lib/Format/BreakableToken.cpp
@@ -186,7 +186,7 @@ BreakableSingleLineToken::BreakableSingleLineToken(
     const FormatStyle &Style)
     : BreakableToken(Tok, InPPDirective, Encoding, Style),
       StartColumn(StartColumn), Prefix(Prefix), Postfix(Postfix) {
-  assert(Tok.TokenText.endswith(Postfix));
+  assert(Tok.TokenText.startswith(Prefix) && Tok.TokenText.endswith(Postfix));
   Line = Tok.TokenText.substr(
       Prefix.size(), Tok.TokenText.size() - Prefix.size() - Postfix.size());
 }
@@ -210,16 +210,9 @@ BreakableStringLiteral::getSplit(unsigned LineIndex, unsigned TailOffset,
 void BreakableStringLiteral::insertBreak(unsigned LineIndex,
                                          unsigned TailOffset, Split Split,
                                          WhitespaceManager &Whitespaces) {
-  unsigned LeadingSpaces = StartColumn;
-  // The '@' of an ObjC string literal (@"Test") does not become part of the
-  // string token.
-  // FIXME: It might be a cleaner solution to merge the tokens as a
-  // precomputation step.
-  if (Prefix.startswith("@"))
-    --LeadingSpaces;
   Whitespaces.replaceWhitespaceInToken(
       Tok, Prefix.size() + TailOffset + Split.first, Split.second, Postfix,
-      Prefix, InPPDirective, 1, LeadingSpaces);
+      Prefix, InPPDirective, 1, StartColumn);
 }
 
 BreakableComment::BreakableComment(const FormatToken &Token,