clang-format: Improve handling of raw string literals.

Especially try to keep existing line breaks before raw string literals,
as the code author might have aligned content to it.

Thereby, clang-format now keeps things like:

  parseStyle(R"(
      BasedOnStyle: Google,
      ColumnLimit: 100)");
  parseStyle(
      R"(BasedOnStyle: Google,
         ColumnLimit: 100)");

llvm-svn: 197368

1 files changed, 4 insertions, 3 deletions

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index c2122ffb7d3..e63f72d65e6 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -136,7 +136,7 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
   if (Style.AlwaysBreakBeforeMultilineStrings &&
       State.Column > State.Stack.back().Indent && // Breaking saves columns.
       !Previous.isOneOf(tok::kw_return, tok::lessless, tok::at) &&
-      Previous.Type != TT_InlineASMColon && NextIsMultilineString(State))
+      Previous.Type != TT_InlineASMColon && nextIsMultilineString(State))
     return true;
   if (((Previous.Type == TT_DictLiteral && Previous.is(tok::l_brace)) ||
        Previous.Type == TT_ArrayInitializerLSquare) &&
@@ -865,12 +865,13 @@ unsigned ContinuationIndenter::getColumnLimit(const LineState &State) const {
   return Style.ColumnLimit - (State.Line->InPPDirective ? 2 : 0);
 }
 
-bool ContinuationIndenter::NextIsMultilineString(const LineState &State) {
+bool ContinuationIndenter::nextIsMultilineString(const LineState &State) {
   const FormatToken &Current = *State.NextToken;
   if (!Current.is(tok::string_literal))
     return false;
   // We never consider raw string literals "multiline" for the purpose of
-  // AlwaysBreakBeforeMultilineStrings implementation.
+  // AlwaysBreakBeforeMultilineStrings implementation as they are special-cased
+  // (see TokenAnnotator::mustBreakBefore().
   if (Current.TokenText.startswith("R\""))
     return false;
   if (Current.IsMultiline)