Revamp indentation behavior for complex binary expressions.

The idea is to indent according to operator precedence and pretty much
identical to how stuff would be indented with parenthesis.

Before:
bool value = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ==
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa *
             bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb +
             bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb &&
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa *
             aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >
             ccccccccccccccccccccccccccccccccccccccccc;

After:
  bool value = aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
                       aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
                       aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ==
                   aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa *
                           bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb +
                       bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb &&
               aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa *
                       aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa >
                   ccccccccccccccccccccccccccccccccccccccccc;

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179049 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 36 insertions, 23 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 101b16f1a1..c78b5b680d 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -86,12 +86,6 @@ static bool isTrailingComment(const AnnotatedToken &Tok) {
          (Tok.Children.empty() || Tok.Children[0].MustBreakBefore);
 }
 
-static bool isComparison(const AnnotatedToken &Tok) {
-  prec::Level Precedence = getPrecedence(Tok);
-  return Tok.Type == TT_BinaryOperator &&
-         (Precedence == prec::Equality || Precedence == prec::Relational);
-}
-
 // Returns the length of everything up to the first possible line break after
 // the ), ], } or > matching \c Tok.
 static unsigned getLengthToMatchingParen(const AnnotatedToken &Tok) {
@@ -492,10 +486,6 @@ public:
     State.StartOfStringLiteral = 0;
     State.StartOfLineLevel = State.ParenLevel;
 
-    DEBUG({
-      DebugTokenState(*State.NextToken);
-    });
-
     // The first token has already been indented and thus consumed.
     moveStateToNextToken(State, /*DryRun=*/ false);
 
@@ -741,8 +731,7 @@ private:
           State.Stack.back().ColonPos =
               State.Column + Current.FormatTok.TokenLength;
         }
-      } else if (Current.Type == TT_StartOfName || Current.is(tok::question) ||
-                 Previous.is(tok::equal) || isComparison(Previous) ||
+      } else if (Current.Type == TT_StartOfName || Previous.is(tok::equal) ||
                  Previous.Type == TT_ObjCMethodExpr) {
         State.Column = ContinuationIndent;
       } else {
@@ -830,9 +819,8 @@ private:
               State.Column + Spaces + Current.FormatTok.TokenLength;
       }
 
-      if (Current.Type != TT_LineComment &&
-          (Previous.isOneOf(tok::l_paren, tok::l_brace) ||
-           State.NextToken->Parent->Type == TT_TemplateOpener))
+      if (opensScope(Previous) && Previous.Type != TT_ObjCMethodExpr &&
+          Current.Type != TT_LineComment)
         State.Stack.back().Indent = State.Column + Spaces;
       if (Previous.is(tok::comma) && !isTrailingComment(Current))
         State.Stack.back().HasMultiParameterLine = true;
@@ -851,9 +839,7 @@ private:
         State.Stack.back().LastSpace = State.Column;
       else if (Previous.Type == TT_InheritanceColon)
         State.Stack.back().Indent = State.Column;
-      else if (Previous.ParameterCount > 1 &&
-               (Previous.isOneOf(tok::l_paren, tok::l_square, tok::l_brace) ||
-                Previous.Type == TT_TemplateOpener))
+      else if (opensScope(Previous) && Previous.ParameterCount > 1)
         // If this function has multiple parameters, indent nested calls from
         // the start of the first parameter.
         State.Stack.back().LastSpace = State.Column;
@@ -879,28 +865,55 @@ private:
       State.Stack.back().StartOfFunctionCall =
           Current.LastInChainOfCalls ? 0 : State.Column;
     if (Current.Type == TT_CtorInitializerColon) {
+      State.Stack.back().Indent = State.Column + 2;
       if (Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
         State.Stack.back().AvoidBinPacking = true;
       State.Stack.back().BreakBeforeParameter = false;
     }
 
+    // If return returns a binary expression, align after it.
+    if (Current.is(tok::kw_return) && !Current.FakeLParens.empty())
+      State.Stack.back().LastSpace = State.Column + 7;
+
     // In ObjC method declaration we align on the ":" of parameters, but we need
     // to ensure that we indent parameters on subsequent lines by at least 4.
     if (Current.Type == TT_ObjCMethodSpecifier)
       State.Stack.back().Indent += 4;
 
     // Insert scopes created by fake parenthesis.
-    for (unsigned i = 0, e = Current.FakeLParens; i != e; ++i) {
+    const AnnotatedToken *Previous = Current.getPreviousNoneComment();
+    // Don't add extra indentation for the first fake parenthesis after
+    // 'return', assignements or opening <({[. The indentation for these cases
+    // is special cased.
+    bool SkipFirstExtraIndent =
+        Current.is(tok::kw_return) ||
+        (Previous && (opensScope(*Previous) ||
+                      getPrecedence(*Previous) == prec::Assignment));
+    for (SmallVector<prec::Level, 4>::const_reverse_iterator
+             I = Current.FakeLParens.rbegin(),
+             E = Current.FakeLParens.rend();
+         I != E; ++I) {
       ParenState NewParenState = State.Stack.back();
-      NewParenState.Indent = std::max(State.Column, State.Stack.back().Indent);
-      NewParenState.BreakBeforeParameter = false;
+      NewParenState.Indent =
+          std::max(std::max(State.Column, NewParenState.Indent),
+                   State.Stack.back().LastSpace);
+
+      // Always indent conditional expressions. Never indent expression where
+      // the 'operator' is ',', ';' or an assignment (i.e. *I <=
+      // prec::Assignment) as those have different indentation rules. Indent
+      // other expression, unless the indentation needs to be skipped.
+      if (*I == prec::Conditional ||
+          (!SkipFirstExtraIndent && *I > prec::Assignment))
+        NewParenState.Indent += 4;
+      if (Previous && !opensScope(*Previous))
+        NewParenState.BreakBeforeParameter = false;
       State.Stack.push_back(NewParenState);
+      SkipFirstExtraIndent = false;
     }
 
     // If we encounter an opening (, [, { or <, we add a level to our stacks to
     // prepare for the following tokens.
-    if (Current.isOneOf(tok::l_paren, tok::l_square, tok::l_brace) ||
-        State.NextToken->Type == TT_TemplateOpener) {
+    if (opensScope(Current)) {
       unsigned NewIndent;
       bool AvoidBinPacking;
       if (Current.is(tok::l_brace)) {