r195240 - Fix bug where optimization would lead to strange line breaks.

[Manuel Klimek]

Author: klimek
Date: Wed Nov 20 05:20:32 2013
New Revision: 195240

URL: http://llvm.org/viewvc/llvm-project?rev=195240&view=rev
Log:
Fix bug where optimization would lead to strange line breaks.

Before:
  void f() {
    CHECK_EQ(aaaa, (
                       *bbbbbbbbb)->cccccc)
        << "qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq";
  }

After:
  void f() {
    CHECK_EQ(aaaa, (*bbbbbbbbb)->cccccc)
        << "qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq";
  }

Modified:
    cfe/trunk/lib/Format/ContinuationIndenter.cpp
    cfe/trunk/lib/Format/ContinuationIndenter.h
    cfe/trunk/unittests/Format/FormatTest.cpp

Modified: cfe/trunk/lib/Format/ContinuationIndenter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/ContinuationIndenter.cpp?rev=195240&r1=195239&r2=195240&view=diff
==============================================================================
--- cfe/trunk/lib/Format/ContinuationIndenter.cpp (original)
+++ cfe/trunk/lib/Format/ContinuationIndenter.cpp Wed Nov 20 05:20:32 2013
@@ -224,13 +224,14 @@ unsigned ContinuationIndenter::addTokenT
   if (Newline)
     Penalty = addTokenOnNewLine(State, DryRun);
   else
-    addTokenOnCurrentLine(State, DryRun, ExtraSpaces);
+    Penalty = addTokenOnCurrentLine(State, DryRun, ExtraSpaces);
 
   return moveStateToNextToken(State, DryRun, Newline) + Penalty;
 }
 
-void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
-                                                 unsigned ExtraSpaces) {
+unsigned ContinuationIndenter::addTokenOnCurrentLine(LineState &State,
+                                                     bool DryRun,
+                                                     unsigned ExtraSpaces) {
   FormatToken &Current = *State.NextToken;
   const FormatToken &Previous = *State.NextToken->Previous;
   if (Current.is(tok::equal) &&
@@ -249,6 +250,15 @@ void ContinuationIndenter::addTokenOnCur
       State.Stack.back().LastSpace = State.Stack.back().VariablePos;
   }
 
+  unsigned Penalty = 0;
+  // A break before a "<<" will get Style.PenaltyBreakFirstLessLess, so a
+  // continuation with "<<" has a smaller penalty in general.
+  // If the LHS is long, we don't want to penalize the break though, so we
+  // also add Style.PenaltyBreakFirstLessLess.
+  if (Current.is(tok::lessless) && State.Stack.back().FirstLessLess == 0 &&
+      State.Column > Style.ColumnLimit / 2)
+    Penalty += Style.PenaltyBreakFirstLessLess;
+
   unsigned Spaces = Current.SpacesRequiredBefore + ExtraSpaces;
 
   if (!DryRun)
@@ -307,6 +317,7 @@ void ContinuationIndenter::addTokenOnCur
         State.Stack[State.Stack.size() - 2].CallContinuation == 0)
       State.Stack.back().LastSpace = State.Column;
   }
+  return Penalty;
 }
 
 unsigned ContinuationIndenter::addTokenOnNewLine(LineState &State,
@@ -332,9 +343,8 @@ unsigned ContinuationIndenter::addTokenO
   Penalty += State.NextToken->SplitPenalty;
 
   // Breaking before the first "<<" is generally not desirable if the LHS is
-  // short.
-  if (Current.is(tok::lessless) && State.Stack.back().FirstLessLess == 0 &&
-      State.Column <= Style.ColumnLimit / 2)
+  // short (not breaking with a long LHS is penalized in addTokenOnCurrentLine).
+  if (Current.is(tok::lessless) && State.Stack.back().FirstLessLess == 0)
     Penalty += Style.PenaltyBreakFirstLessLess;
 
   if (Current.is(tok::l_brace) && Current.BlockKind == BK_Block) {

Modified: cfe/trunk/lib/Format/ContinuationIndenter.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/ContinuationIndenter.h?rev=195240&r1=195239&r2=195240&view=diff
==============================================================================
--- cfe/trunk/lib/Format/ContinuationIndenter.h (original)
+++ cfe/trunk/lib/Format/ContinuationIndenter.h Wed Nov 20 05:20:32 2013
@@ -91,8 +91,8 @@ private:
   ///
   /// If \p DryRun is \c false, also creates and stores the required
   /// \c Replacement.
-  void addTokenOnCurrentLine(LineState &State, bool DryRun,
-                             unsigned ExtraSpaces);
+  unsigned addTokenOnCurrentLine(LineState &State, bool DryRun,
+                                 unsigned ExtraSpaces);
 
   /// \brief Appends the next token to \p State and updates information
   /// necessary for indentation.

Modified: cfe/trunk/unittests/Format/FormatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTest.cpp?rev=195240&r1=195239&r2=195240&view=diff
==============================================================================
--- cfe/trunk/unittests/Format/FormatTest.cpp (original)
+++ cfe/trunk/unittests/Format/FormatTest.cpp Wed Nov 20 05:20:32 2013
@@ -3744,6 +3744,11 @@ TEST_F(FormatTest, AlignsPipes) {
   EXPECT_EQ("llvm::errs() << \"\n"
             "             << a;",
             format("llvm::errs() << \"\n<<a;"));
+
+  verifyFormat("void f() {\n"
+               "  CHECK_EQ(aaaa, (*bbbbbbbbb)->cccccc)\n"
+               "      << \"qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq\";\n"
+               "}");
 }
 
 TEST_F(FormatTest, UnderstandsEquals) {