r175999 - Allow breaking between a type and name in variable declarations.

Daniel Jasper djasper at google.com
Sun Feb 24 10:54:33 PST 2013


Author: djasper
Date: Sun Feb 24 12:54:32 2013
New Revision: 175999

URL: http://llvm.org/viewvc/llvm-project?rev=175999&view=rev
Log:
Allow breaking between a type and name in variable declarations.

This fixes llvm.org/PR14967 and is generall necessary to avoid
situations where the column limit is exceeded. The challenge is
restricting such lines splits, otherwise clang-format suddenly starts
breaking at bad places.

Before:
ReallyLongReturnType<TemplateParam1, TemplateParam2>
ReallyReallyLongFunctionName(
    const std::string &SomeParameter,
    const SomeType<string,
                   SomeOtherTemplateParameter> &ReallyReallyLongParameterName,
    const SomeType<string,
                   SomeOtherTemplateParameter> &AnotherLongParameterName) {}

After:
ReallyLongReturnType<TemplateParam1, TemplateParam2>
ReallyReallyLongFunctionName(
    const std::string &SomeParameter,
    const SomeType<string, SomeOtherTemplateParameter> &
        ReallyReallyLongParameterName,
    const SomeType<string, SomeOtherTemplateParameter> &
        AnotherLongParameterName) {}

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

Modified: cfe/trunk/lib/Format/Format.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/Format.cpp?rev=175999&r1=175998&r2=175999&view=diff
==============================================================================
--- cfe/trunk/lib/Format/Format.cpp (original)
+++ cfe/trunk/lib/Format/Format.cpp Sun Feb 24 12:54:32 2013
@@ -258,12 +258,6 @@ private:
   tooling::Replacements Replaces;
 };
 
-static bool isVarDeclName(const AnnotatedToken &Tok) {
-  return Tok.Parent != NULL && Tok.is(tok::identifier) &&
-         (Tok.Parent->Type == TT_PointerOrReference ||
-          Tok.Parent->is(tok::identifier));
-}
-
 class UnwrappedLineFormatter {
 public:
   UnwrappedLineFormatter(const FormatStyle &Style, SourceManager &SourceMgr,
@@ -498,8 +492,8 @@ private:
                  ((RootToken.is(tok::kw_for) && State.ParenLevel == 1) ||
                   State.ParenLevel == 0)) {
         State.Column = State.VariablePos;
-      } else if (State.NextToken->Parent->ClosesTemplateDeclaration ||
-                 Current.Type == TT_StartOfName) {
+      } else if (Previous.ClosesTemplateDeclaration ||
+                 (Current.Type == TT_StartOfName && State.ParenLevel == 0)) {
         State.Column = State.Stack.back().Indent - 4;
       } else if (Current.Type == TT_ObjCSelectorName) {
         if (State.Stack.back().ColonPos > Current.FormatTok.TokenLength) {
@@ -510,7 +504,8 @@ private:
           State.Stack.back().ColonPos =
               State.Column + Current.FormatTok.TokenLength;
         }
-      } else if (Previous.Type == TT_ObjCMethodExpr || isVarDeclName(Current)) {
+      } else if (Previous.Type == TT_ObjCMethodExpr ||
+                 Current.Type == TT_StartOfName) {
         State.Column = State.Stack.back().Indent + 4;
       } else {
         State.Column = State.Stack.back().Indent;
@@ -551,8 +546,7 @@ private:
       if (State.Stack.back().AvoidBinPacking) {
         // If we are breaking after '(', '{', '<', this is not bin packing
         // unless AllowAllParametersOfDeclarationOnNextLine is false.
-        if ((Previous.isNot(tok::l_paren) && Previous.isNot(tok::l_brace) &&
-             Previous.Type != TT_TemplateOpener) ||
+        if ((Previous.isNot(tok::l_paren) && Previous.isNot(tok::l_brace)) ||
             (!Style.AllowAllParametersOfDeclarationOnNextLine &&
              Line.MustBeDeclaration))
           State.Stack.back().BreakBeforeParameter = true;

Modified: cfe/trunk/lib/Format/TokenAnnotator.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/TokenAnnotator.cpp?rev=175999&r1=175998&r2=175999&view=diff
==============================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.cpp (original)
+++ cfe/trunk/lib/Format/TokenAnnotator.cpp Sun Feb 24 12:54:32 2013
@@ -83,7 +83,6 @@ public:
       : SourceMgr(SourceMgr), Lex(Lex), Line(Line), CurrentToken(&Line.First),
         KeywordVirtualFound(false), Ident_in(Ident_in) {
     Contexts.push_back(Context(1, /*IsExpression=*/ false));
-    Contexts.back().LookForFunctionName = Line.MustBeDeclaration;
   }
 
 private:
@@ -348,6 +347,8 @@ private:
     case tok::l_paren:
       if (!parseParens())
         return false;
+      if (Line.MustBeDeclaration)
+        Line.MightBeFunctionDecl = true;
       break;
     case tok::l_square:
       if (!parseSquare())
@@ -520,8 +521,7 @@ private:
     Context(unsigned BindingStrength, bool IsExpression)
         : BindingStrength(BindingStrength), LongestObjCSelectorName(0),
           ColonIsForRangeExpr(false), ColonIsObjCMethodExpr(false),
-          FirstObjCSelectorName(NULL), IsExpression(IsExpression),
-          LookForFunctionName(false) {}
+          FirstObjCSelectorName(NULL), IsExpression(IsExpression) {}
 
     unsigned BindingStrength;
     unsigned LongestObjCSelectorName;
@@ -529,7 +529,6 @@ private:
     bool ColonIsObjCMethodExpr;
     AnnotatedToken *FirstObjCSelectorName;
     bool IsExpression;
-    bool LookForFunctionName;
   };
 
   /// \brief Puts a new \c Context onto the stack \c Contexts for the lifetime
@@ -572,9 +571,13 @@ private:
     }
 
     if (Current.Type == TT_Unknown) {
-      if (Contexts.back().LookForFunctionName && Current.is(tok::l_paren)) {
-        findFunctionName(&Current);
-        Contexts.back().LookForFunctionName = false;
+      if (Current.Parent && Current.is(tok::identifier) &&
+          ((Current.Parent->is(tok::identifier) &&
+            Current.Parent->FormatTok.Tok.getIdentifierInfo()
+                ->getPPKeywordID() == tok::pp_not_keyword) ||
+           Current.Parent->Type == TT_PointerOrReference ||
+           Current.Parent->Type == TT_TemplateCloser)) {
+        Current.Type = TT_StartOfName;
       } else if (Current.is(tok::star) || Current.is(tok::amp)) {
         Current.Type =
             determineStarAmpUsage(Current, Contexts.back().IsExpression);
@@ -623,22 +626,6 @@ private:
     }
   }
 
-  /// \brief Starting from \p Current, this searches backwards for an
-  /// identifier which could be the start of a function name and marks it.
-  void findFunctionName(AnnotatedToken *Current) {
-    AnnotatedToken *Parent = Current->Parent;
-    while (Parent != NULL && Parent->Parent != NULL) {
-      if (Parent->is(tok::identifier) &&
-          (Parent->Parent->is(tok::identifier) ||
-           Parent->Parent->Type == TT_PointerOrReference ||
-           Parent->Parent->Type == TT_TemplateCloser)) {
-        Parent->Type = TT_StartOfName;
-        break;
-      }
-      Parent = Parent->Parent;
-    }
-  }
-
   /// \brief Return the type of the given token assuming it is * or &.
   TokenType
   determineStarAmpUsage(const AnnotatedToken &Tok, bool IsExpression) {
@@ -883,8 +870,15 @@ unsigned TokenAnnotator::splitPenalty(co
   const AnnotatedToken &Left = *Tok.Parent;
   const AnnotatedToken &Right = Tok;
 
-  if (Right.Type == TT_StartOfName)
-    return Style.PenaltyReturnTypeOnItsOwnLine;
+  if (Right.Type == TT_StartOfName) {
+    if (Line.First.is(tok::kw_for))
+      return 3;
+    else if (Line.MightBeFunctionDecl && Right.BindingStrength == 1)
+      // FIXME: Clean up hack of using BindingStrength to find top-level names.
+      return Style.PenaltyReturnTypeOnItsOwnLine;
+    else
+      return 100;
+  }
   if (Left.is(tok::l_brace) && Right.isNot(tok::l_brace))
     return 50;
   if (Left.is(tok::equal) && Right.is(tok::l_brace))
@@ -941,7 +935,7 @@ unsigned TokenAnnotator::splitPenalty(co
 
   if (Level != prec::Unknown)
     return Level;
-
+  
   return 3;
 }
 
@@ -1099,12 +1093,6 @@ bool TokenAnnotator::canBreakBefore(cons
     // change the "binding" behavior of a comment.
     return false;
 
-  // FIXME: We can probably remove this special case once we have implemented
-  // breaking after types in general.
-  if (Line.First.is(tok::kw_for) && !Right.Children.empty() &&
-      Right.Children[0].is(tok::equal))
-    return true;
-
   // Allow breaking after a trailing 'const', e.g. after a method declaration,
   // unless it is follow by ';', '{' or '='.
   if (Left.is(tok::kw_const) && Left.Parent != NULL &&

Modified: cfe/trunk/lib/Format/TokenAnnotator.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Format/TokenAnnotator.h?rev=175999&r1=175998&r2=175999&view=diff
==============================================================================
--- cfe/trunk/lib/Format/TokenAnnotator.h (original)
+++ cfe/trunk/lib/Format/TokenAnnotator.h Sun Feb 24 12:54:32 2013
@@ -140,7 +140,8 @@ public:
   AnnotatedLine(const UnwrappedLine &Line)
       : First(Line.Tokens.front()), Level(Line.Level),
         InPPDirective(Line.InPPDirective),
-        MustBeDeclaration(Line.MustBeDeclaration) {
+        MustBeDeclaration(Line.MustBeDeclaration),
+        MightBeFunctionDecl(false) {
     assert(!Line.Tokens.empty());
     AnnotatedToken *Current = &First;
     for (std::list<FormatToken>::const_iterator I = ++Line.Tokens.begin(),
@@ -155,7 +156,8 @@ public:
   AnnotatedLine(const AnnotatedLine &Other)
       : First(Other.First), Type(Other.Type), Level(Other.Level),
         InPPDirective(Other.InPPDirective),
-        MustBeDeclaration(Other.MustBeDeclaration) {
+        MustBeDeclaration(Other.MustBeDeclaration),
+        MightBeFunctionDecl(Other.MightBeFunctionDecl) {
     Last = &First;
     while (!Last->Children.empty()) {
       Last->Children[0].Parent = Last;
@@ -170,6 +172,7 @@ public:
   unsigned Level;
   bool InPPDirective;
   bool MustBeDeclaration;
+  bool MightBeFunctionDecl;
 };
 
 inline prec::Level getPrecedence(const AnnotatedToken &Tok) {

Modified: cfe/trunk/unittests/Format/FormatTest.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/unittests/Format/FormatTest.cpp?rev=175999&r1=175998&r2=175999&view=diff
==============================================================================
--- cfe/trunk/unittests/Format/FormatTest.cpp (original)
+++ cfe/trunk/unittests/Format/FormatTest.cpp Sun Feb 24 12:54:32 2013
@@ -1931,13 +1931,24 @@ TEST_F(FormatTest, FormatsFunctionTypes)
   verifyFormat("int(*func)(void *);");
 }
 
-TEST_F(FormatTest, BreaksFunctionDeclarations) {
+TEST_F(FormatTest, BreaksLongDeclarations) {
   verifyFormat("int *someFunction(int LoooooooooooooooooooongParam1,\n"
                "                  int LoooooooooooooooooooongParam2) {}");
   verifyFormat(
       "TypeSpecDecl *\n"
       "TypeSpecDecl::Create(ASTContext &C, DeclContext *DC, SourceLocation L,\n"
       "                     IdentifierIn *II, Type *T) {}");
+  verifyFormat("ReallyLongReturnType<TemplateParam1, TemplateParam2>\n"
+               "ReallyReallyLongFunctionName(\n"
+               "    const std::string &SomeParameter,\n"
+               "    const SomeType<string, SomeOtherTemplateParameter> &\n"
+               "        ReallyReallyLongParameterName,\n"
+               "    const SomeType<string, SomeOtherTemplateParameter> &\n"
+               "        AnotherLongParameterName) {}");
+  verifyFormat(
+      "aaaaaaaaaaaaaaaa::aaaaaaaaaaaaaaaa<aaaaaaaaaaaaa, aaaaaaaaaaaa>\n"
+      "aaaaaaaaaaaaaaaaaaaaaaa;");
+
   verifyGoogleFormat(
       "TypeSpecDecl* TypeSpecDecl::Create(\n"
       "    ASTContext& C, DeclContext* DC, SourceLocation L) {}");





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