clang-format: Add special case to reduce indentaiton in streams.

This is similar to how we treat assignments and seems to be generally
desirable.

Before:
  llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(
                      aaaaaaaaaaaaaaaaaaaaaaaaaaaa,
                      aaaaaaaaaaaaaaaaaaaaaaaaaaaa);

After:
  llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(
      aaaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaaa);

llvm-svn: 206384

clang/lib/Format/ContinuationIndenter.cpp

@@ -301,7 +301,9 @@ void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
   else if ((Previous.Type == TT_BinaryOperator ||
             Previous.Type == TT_ConditionalExpr ||
             Previous.Type == TT_CtorInitializerColon) &&
-           (Previous.getPrecedence() != prec::Assignment ||
+           ((Previous.getPrecedence() != prec::Assignment &&
+             (Previous.isNot(tok::lessless) || Previous.OperatorIndex != 0 ||
+              !Previous.LastOperator)) ||
             Current.StartsBinaryExpression))
     // Always indent relative to the RHS of the expression unless this is a
     // simple assignment without binary expression on the RHS. Also indent
@@ -573,7 +575,7 @@ unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
         std::min(State.LowestLevelOnLine, State.ParenLevel);
   if (Current.isMemberAccess())
     State.Stack.back().StartOfFunctionCall =
-        Current.LastInChainOfCalls ? 0 : State.Column + Current.ColumnWidth;
+        Current.LastOperator ? 0 : State.Column + Current.ColumnWidth;
   if (Current.Type == TT_ObjCSelectorName)
     State.Stack.back().ObjCSelectorNameFound = true;
   if (Current.Type == TT_LambdaLSquare)

clang/lib/Format/FormatToken.h

@@ -106,8 +106,9 @@ struct FormatToken {
         UnbreakableTailLength(0), BindingStrength(0), NestingLevel(0),
         SplitPenalty(0), LongestObjCSelectorName(0), FakeRParens(0),
         StartsBinaryExpression(false), EndsBinaryExpression(false),
-        LastInChainOfCalls(false), PartOfMultiVariableDeclStmt(false),
-        IsForEachMacro(false), MatchingParen(NULL), Previous(NULL), Next(NULL),
+        OperatorIndex(0), LastOperator(false),
+        PartOfMultiVariableDeclStmt(false), IsForEachMacro(false),
+        MatchingParen(NULL), Previous(NULL), Next(NULL),
         Decision(FD_Unformatted), Finalized(false) {}
 
   /// \brief The \c Token.
@@ -242,8 +243,13 @@ struct FormatToken {
   /// \brief \c true if this token ends a binary expression.
   bool EndsBinaryExpression;
 
-  /// \brief Is this the last "." or "->" in a builder-type call?
-  bool LastInChainOfCalls;
+  /// \brief Is this is an operator (or "."/"->") in a sequence of operators
+  /// with the same precedence, contains the 0-based operator index.
+  unsigned OperatorIndex;
+
+  /// \brief Is this the last operator (or "."/"->") in a sequence of operators
+  /// with the same precedence?
+  bool LastOperator;
 
   /// \brief Is this token part of a \c DeclStmt defining multiple variables?
   ///

clang/lib/Format/TokenAnnotator.cpp

@@ -978,6 +978,7 @@ public:
 
     FormatToken *Start = Current;
     FormatToken *LatestOperator = NULL;
+    unsigned OperatorIndex = 0;
 
     while (Current) {
       // Consume operators with higher precedence.
@@ -997,8 +998,8 @@ public:
       if (Current == NULL || Current->closesScope() ||
           (CurrentPrecedence != -1 && CurrentPrecedence < Precedence)) {
         if (LatestOperator) {
+          LatestOperator->LastOperator = true;
           if (Precedence == PrecedenceArrowAndPeriod) {
-            LatestOperator->LastInChainOfCalls = true;
             // Call expressions don't have a binary operator precedence.
             addFakeParenthesis(Start, prec::Unknown);
           } else {
@@ -1017,8 +1018,11 @@ public:
         next();
       } else {
         // Operator found.
-        if (CurrentPrecedence == Precedence)
+        if (CurrentPrecedence == Precedence) {
           LatestOperator = Current;
+          Current->OperatorIndex = OperatorIndex;
+          ++OperatorIndex;
+        }
 
         next();
       }

clang/unittests/Format/FormatTest.cpp

@@ -3983,6 +3983,18 @@ TEST_F(FormatTest, AlignsPipes) {
       "aaaaaaaa << (aaaaaaaaaaaaaaaaaaa << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\n"
       "                                 << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
       "         << aaaaaaaaaaaaaaaaaaaaaaaaaaaaa;");
+  verifyFormat(
+      "llvm::errs() << \"a: \" << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "                             aaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+      "                             aaaaaaaaaaaaaaaaaaaaaaaaaaaa);");
+  verifyFormat(
+      "llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "                    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+      "                    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+      "             << bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb;");
+  verifyFormat(
+      "llvm::errs() << aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(\n"
+      "    aaaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaaa);");
 
   verifyFormat("return out << \"somepacket = {\\n\"\n"
                "           << \" aaaaaa = \" << pkt.aaaaaa << \"\\n\"\n"