Improve formatting of for loops and multi-variable DeclStmts.

This combines several related changes:
a) Don't break before after the variable types in for loops with a
   single variable.
b) Better indent DeclStmts defining multiple variables.

Before:
bool aaaaaaaaaaaaaaaaaaaaaaaaa =
    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaa),
     bbbbbbbbbbbbbbbbbbbbbbbbb =
         bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(bbbbbbbbbbbbbbbb);
for (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
         aaaaaaaaaaa = aaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaa;
     aaaaaaaaaaa != aaaaaaaaaaaaaaaaaaa; ++aaaaaaaaaaa) {
}

After:
bool aaaaaaaaaaaaaaaaaaaaaaaaa =
         aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaa),
     bbbbbbbbbbbbbbbbbbbbbbbbb =
         bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb(bbbbbbbbbbbbbbbb);
for (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa aaaaaaaaaaa =
         aaaaaaaaaaaaaaaa.aaaaaaaaaaaaaaa;
     aaaaaaaaaaa != aaaaaaaaaaaaaaaaaaa; ++aaaaaaaaaaa) {
}

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178641 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 70 insertions, 21 deletions

diff --git a/lib/Format/Format.cpp b/lib/Format/Format.cpp
index 4d9a228f8c..1e0178e14e 100644
--- a/lib/Format/Format.cpp
+++ b/lib/Format/Format.cpp
@@ -487,7 +487,6 @@ public:
     State.Stack.push_back(
         ParenState(FirstIndent, FirstIndent, !Style.BinPackParameters,
                    /*HasMultiParameterLine=*/ false));
-    State.VariablePos = 0;
     State.LineContainsContinuedForLoopSection = false;
     State.ParenLevel = 0;
     State.StartOfStringLiteral = 0;
@@ -537,7 +536,7 @@ private:
           AvoidBinPacking(AvoidBinPacking), BreakBeforeParameter(false),
           HasMultiParameterLine(HasMultiParameterLine), ColonPos(0),
           StartOfFunctionCall(0), NestedNameSpecifierContinuation(0),
-          CallContinuation(0) {}
+          CallContinuation(0), VariablePos(0) {}
 
     /// \brief The position to which a specific parenthesis level needs to be
     /// indented.
@@ -591,6 +590,11 @@ private:
     /// contains the start column of the second line. Otherwise 0.
     unsigned CallContinuation;
 
+    /// \brief The column of the first variable name in a variable declaration.
+    ///
+    /// Used to align further variables if necessary.
+    unsigned VariablePos;
+
     bool operator<(const ParenState &Other) const {
       if (Indent != Other.Indent)
         return Indent < Other.Indent;
@@ -618,6 +622,8 @@ private:
                Other.NestedNameSpecifierContinuation;
       if (CallContinuation != Other.CallContinuation)
         return CallContinuation < Other.CallContinuation;
+      if (VariablePos != Other.VariablePos)
+        return VariablePos < Other.VariablePos;
       return false;
     }
   };
@@ -632,11 +638,6 @@ private:
     /// \brief The token that needs to be next formatted.
     const AnnotatedToken *NextToken;
 
-    /// \brief The column of the first variable name in a variable declaration.
-    ///
-    /// Used to align further variables if necessary.
-    unsigned VariablePos;
-
     /// \brief \c true if this line contains a continued for-loop section.
     bool LineContainsContinuedForLoopSection;
 
@@ -660,8 +661,6 @@ private:
         return NextToken < Other.NextToken;
       if (Column != Other.Column)
         return Column < Other.Column;
-      if (VariablePos != Other.VariablePos)
-        return VariablePos < Other.VariablePos;
       if (LineContainsContinuedForLoopSection !=
               Other.LineContainsContinuedForLoopSection)
         return LineContainsContinuedForLoopSection;
@@ -727,10 +726,9 @@ private:
         }
       } else if (Current.Type == TT_ConditionalExpr) {
         State.Column = State.Stack.back().QuestionColumn;
-      } else if (Previous.is(tok::comma) && State.VariablePos != 0 &&
-                 ((RootToken.is(tok::kw_for) && State.ParenLevel == 1) ||
-                  State.ParenLevel == 0)) {
-        State.Column = State.VariablePos;
+      } else if (Previous.is(tok::comma) &&
+                 State.Stack.back().VariablePos != 0) {
+        State.Column = State.Stack.back().VariablePos;
       } else if (Previous.ClosesTemplateDeclaration ||
                  (Current.Type == TT_StartOfName && State.ParenLevel == 0)) {
         State.Column = State.Stack.back().Indent;
@@ -799,10 +797,13 @@ private:
           State.Stack.back().BreakBeforeParameter = true;
       }
     } else {
-      // FIXME: Put VariablePos into ParenState and remove second part of if().
       if (Current.is(tok::equal) &&
-          (RootToken.is(tok::kw_for) || State.ParenLevel == 0))
-        State.VariablePos = State.Column - Previous.FormatTok.TokenLength;
+          (RootToken.is(tok::kw_for) || State.ParenLevel == 0)) {
+        State.Stack.back().VariablePos =
+            State.Column - Previous.FormatTok.TokenLength;
+        if (Previous.PartOfMultiVariableDeclStmt)
+          State.Stack.back().LastSpace = State.Stack.back().VariablePos;
+      }
 
       unsigned Spaces = State.NextToken->SpacesRequiredBefore;
 
@@ -828,7 +829,7 @@ private:
         State.Stack.back().HasMultiParameterLine = true;
 
       State.Column += Spaces;
-      if (Current.is(tok::l_paren) && Previous.is(tok::kw_if))
+      if (Current.is(tok::l_paren) && Previous.isOneOf(tok::kw_if, tok::kw_for))
         // Treat the condition inside an if as if it was a second function
         // parameter, i.e. let nested calls have an indent of 4.
         State.Stack.back().LastSpace = State.Column + 1; // 1 is length of "(".
@@ -926,9 +927,11 @@ private:
     }
 
     // Remove scopes created by fake parenthesis.
+    unsigned VariablePos = State.Stack.back().VariablePos;
     for (unsigned i = 0, e = Current.FakeRParens; i != e; ++i) {
       State.Stack.pop_back();
     }
+    State.Stack.back().VariablePos = VariablePos;
 
     if (Current.is(tok::string_literal)) {
       State.StartOfStringLiteral = State.Column;
diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 23c5a46355..427157e332 100644
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -408,6 +408,10 @@ private:
           Tok->FormatTok.Tok.getIdentifierInfo() == &Ident_in)
         Tok->Type = TT_ObjCForIn;
       break;
+    case tok::comma:
+      if (Contexts.back().FirstStartOfName)
+        Contexts.back().FirstStartOfName->PartOfMultiVariableDeclStmt = true;
+      break;
     default:
       break;
     }
@@ -538,7 +542,8 @@ private:
         : ContextKind(ContextKind), BindingStrength(BindingStrength),
           LongestObjCSelectorName(0), ColonIsForRangeExpr(false),
           ColonIsObjCMethodExpr(false), FirstObjCSelectorName(NULL),
-          IsExpression(IsExpression), CanBeExpression(true) {}
+          FirstStartOfName(NULL), IsExpression(IsExpression),
+          CanBeExpression(true) {}
 
     tok::TokenKind ContextKind;
     unsigned BindingStrength;
@@ -546,6 +551,7 @@ private:
     bool ColonIsForRangeExpr;
     bool ColonIsObjCMethodExpr;
     AnnotatedToken *FirstObjCSelectorName;
+    AnnotatedToken *FirstStartOfName;
     bool IsExpression;
     bool CanBeExpression;
   };
@@ -600,8 +606,10 @@ private:
           ((Current.Parent->is(tok::identifier) &&
             Current.Parent->FormatTok.Tok.getIdentifierInfo()
                 ->getPPKeywordID() == tok::pp_not_keyword) ||
+           isSimpleTypeSpecifier(*Current.Parent) ||
            Current.Parent->Type == TT_PointerOrReference ||
            Current.Parent->Type == TT_TemplateCloser)) {
+        Contexts.back().FirstStartOfName = &Current;
         Current.Type = TT_StartOfName;
       } else if (Current.isOneOf(tok::star, tok::amp, tok::ampamp)) {
         Current.Type =
@@ -720,6 +728,39 @@ private:
     return TT_UnaryOperator;
   }
 
+  // FIXME: This is copy&pasted from Sema. Put it in a common place and remove
+  // duplication.
+  /// \brief Determine whether the token kind starts a simple-type-specifier.
+  bool isSimpleTypeSpecifier(const AnnotatedToken &Tok) const {
+    switch (Tok.FormatTok.Tok.getKind()) {
+    case tok::kw_short:
+    case tok::kw_long:
+    case tok::kw___int64:
+    case tok::kw___int128:
+    case tok::kw_signed:
+    case tok::kw_unsigned:
+    case tok::kw_void:
+    case tok::kw_char:
+    case tok::kw_int:
+    case tok::kw_half:
+    case tok::kw_float:
+    case tok::kw_double:
+    case tok::kw_wchar_t:
+    case tok::kw_bool:
+    case tok::kw___underlying_type:
+      return true;
+    case tok::annot_typename:
+    case tok::kw_char16_t:
+    case tok::kw_char32_t:
+    case tok::kw_typeof:
+    case tok::kw_decltype:
+      return Lex.getLangOpts().CPlusPlus;
+    default:
+      break;
+    }
+    return false;
+  }
+
   SmallVector<Context, 8> Contexts;
 
   SourceManager &SourceMgr;
@@ -886,7 +927,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
   const AnnotatedToken &Right = Tok;
 
   if (Right.Type == TT_StartOfName) {
-    if (Line.First.is(tok::kw_for))
+    if (Line.First.is(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
       return 3;
     else if (Line.MightBeFunctionDecl && Right.BindingStrength == 1)
       // FIXME: Clean up hack of using BindingStrength to find top-level names.
diff --git a/lib/Format/TokenAnnotator.h b/lib/Format/TokenAnnotator.h
index 013dd2d27c..c41ee33c43 100644
--- a/lib/Format/TokenAnnotator.h
+++ b/lib/Format/TokenAnnotator.h
@@ -76,8 +76,8 @@ public:
         ClosesTemplateDeclaration(false), MatchingParen(NULL),
         ParameterCount(0), BindingStrength(0), SplitPenalty(0),
         LongestObjCSelectorName(0), Parent(NULL), FakeLParens(0),
-        FakeRParens(0), LastInChainOfCalls(false) {
-  }
+        FakeRParens(0), LastInChainOfCalls(false),
+        PartOfMultiVariableDeclStmt(false) {}
 
   bool is(tok::TokenKind Kind) const { return FormatTok.Tok.is(Kind); }
 
@@ -166,6 +166,11 @@ public:
   /// \brief Is this the last "." or "->" in a builder-type call?
   bool LastInChainOfCalls;
 
+  /// \brief Is this token part of a \c DeclStmt defining multiple variables?
+  ///
+  /// Only set if \c Type == \c TT_StartOfName.
+  bool PartOfMultiVariableDeclStmt;
+
   const AnnotatedToken *getPreviousNoneComment() const {
     AnnotatedToken *Tok = Parent;
     while (Tok != NULL && Tok->is(tok::comment))