Support AlwaysBreakAfterReturnType

This changes the behavior of AlwaysBreakAfterDeclarationReturnType
so that it supports breaking after declarations, definitions, or
both.

Differential Revision: http://reviews.llvm.org/D10370
Reviewed By: Daniel Jasper

llvm-svn: 256046

4 files changed, 72 insertions, 13 deletions

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 3b6e1938378..41451b91f88 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -125,10 +125,10 @@ bool ContinuationIndenter::canBreak(const LineState &State) {
 
   // Don't break after very short return types (e.g. "void") as that is often
   // unexpected.
-  if (Current.is(TT_FunctionDeclarationName) &&
-      Style.AlwaysBreakAfterDefinitionReturnType == FormatStyle::DRTBS_None &&
-      State.Column < 6)
-    return false;
+  if (Current.is(TT_FunctionDeclarationName) && State.Column < 6) {
+    if (Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_None)
+      return false;
+  }
 
   return !State.Stack.back().NoLineBreak;
 }
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index a7e0799c119..97195aa9462 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -105,6 +105,18 @@ template <> struct ScalarEnumerationTraits<FormatStyle::BraceBreakingStyle> {
 };
 
 template <>
+struct ScalarEnumerationTraits<FormatStyle::ReturnTypeBreakingStyle> {
+  static void enumeration(IO &IO, FormatStyle::ReturnTypeBreakingStyle &Value) {
+    IO.enumCase(Value, "None", FormatStyle::RTBS_None);
+    IO.enumCase(Value, "All", FormatStyle::RTBS_All);
+    IO.enumCase(Value, "TopLevel", FormatStyle::RTBS_TopLevel);
+    IO.enumCase(Value, "TopLevelDefinitions",
+                FormatStyle::RTBS_TopLevelDefinitions);
+    IO.enumCase(Value, "AllDefinitions", FormatStyle::RTBS_AllDefinitions);
+  }
+};
+
+template <>
 struct ScalarEnumerationTraits<FormatStyle::DefinitionReturnTypeBreakingStyle> {
   static void
   enumeration(IO &IO, FormatStyle::DefinitionReturnTypeBreakingStyle &Value) {
@@ -233,6 +245,21 @@ template <> struct MappingTraits<FormatStyle> {
                    Style.AllowShortLoopsOnASingleLine);
     IO.mapOptional("AlwaysBreakAfterDefinitionReturnType",
                    Style.AlwaysBreakAfterDefinitionReturnType);
+    IO.mapOptional("AlwaysBreakAfterReturnType",
+                   Style.AlwaysBreakAfterReturnType);
+    // If AlwaysBreakAfterDefinitionReturnType was specified but
+    // AlwaysBreakAfterReturnType was not, initialize the latter from the
+    // former for backwards compatibility.
+    if (Style.AlwaysBreakAfterDefinitionReturnType != FormatStyle::DRTBS_None &&
+        Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_None) {
+      if (Style.AlwaysBreakAfterDefinitionReturnType == FormatStyle::DRTBS_All)
+        Style.AlwaysBreakAfterReturnType = FormatStyle::RTBS_AllDefinitions;
+      else if (Style.AlwaysBreakAfterDefinitionReturnType ==
+               FormatStyle::DRTBS_TopLevel)
+        Style.AlwaysBreakAfterReturnType =
+            FormatStyle::RTBS_TopLevelDefinitions;
+    }
+
     IO.mapOptional("AlwaysBreakBeforeMultilineStrings",
                    Style.AlwaysBreakBeforeMultilineStrings);
     IO.mapOptional("AlwaysBreakTemplateDeclarations",
@@ -449,6 +476,7 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.AllowShortCaseLabelsOnASingleLine = false;
   LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
   LLVMStyle.AllowShortLoopsOnASingleLine = false;
+  LLVMStyle.AlwaysBreakAfterReturnType = FormatStyle::RTBS_None;
   LLVMStyle.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_None;
   LLVMStyle.AlwaysBreakBeforeMultilineStrings = false;
   LLVMStyle.AlwaysBreakTemplateDeclarations = false;
@@ -585,6 +613,8 @@ FormatStyle getMozillaStyle() {
   FormatStyle MozillaStyle = getLLVMStyle();
   MozillaStyle.AllowAllParametersOfDeclarationOnNextLine = false;
   MozillaStyle.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Inline;
+  MozillaStyle.AlwaysBreakAfterReturnType =
+      FormatStyle::RTBS_TopLevelDefinitions;
   MozillaStyle.AlwaysBreakAfterDefinitionReturnType =
       FormatStyle::DRTBS_TopLevel;
   MozillaStyle.AlwaysBreakTemplateDeclarations = true;
@@ -624,6 +654,7 @@ FormatStyle getWebKitStyle() {
 FormatStyle getGNUStyle() {
   FormatStyle Style = getLLVMStyle();
   Style.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_All;
+  Style.AlwaysBreakAfterReturnType = FormatStyle::RTBS_AllDefinitions;
   Style.BreakBeforeBinaryOperators = FormatStyle::BOS_All;
   Style.BreakBeforeBraces = FormatStyle::BS_GNU;
   Style.BreakBeforeTernaryOperators = true;
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index b8487e10359..e06389c3172 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1562,6 +1562,29 @@ static bool isFunctionDeclarationName(const FormatToken &Current) {
   return false;
 }
 
+bool TokenAnnotator::mustBreakForReturnType(const AnnotatedLine &Line) const {
+  assert(Line.MightBeFunctionDecl);
+
+  if ((Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_TopLevel ||
+       Style.AlwaysBreakAfterReturnType ==
+           FormatStyle::RTBS_TopLevelDefinitions) &&
+      Line.Level > 0)
+    return false;
+
+  switch (Style.AlwaysBreakAfterReturnType) {
+  case FormatStyle::RTBS_None:
+    return false;
+  case FormatStyle::RTBS_All:
+  case FormatStyle::RTBS_TopLevel:
+    return true;
+  case FormatStyle::RTBS_AllDefinitions:
+  case FormatStyle::RTBS_TopLevelDefinitions:
+    return Line.mightBeFunctionDefinition();
+  }
+
+  return false;
+}
+
 void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
   for (SmallVectorImpl<AnnotatedLine *>::iterator I = Line.Children.begin(),
                                                   E = Line.Children.end();
@@ -1613,15 +1636,9 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
     Current->MustBreakBefore =
         Current->MustBreakBefore || mustBreakBefore(Line, *Current);
 
-    if ((Style.AlwaysBreakAfterDefinitionReturnType == FormatStyle::DRTBS_All ||
-         (Style.AlwaysBreakAfterDefinitionReturnType ==
-              FormatStyle::DRTBS_TopLevel &&
-          Line.Level == 0)) &&
-        InFunctionDecl && Current->is(TT_FunctionDeclarationName) &&
-        !Line.Last->isOneOf(tok::semi, tok::comment)) // Only for definitions.
-      // FIXME: Line.Last points to other characters than tok::semi
-      // and tok::lbrace.
-      Current->MustBreakBefore = true;
+    if (!Current->MustBreakBefore && InFunctionDecl &&
+        Current->is(TT_FunctionDeclarationName))
+      Current->MustBreakBefore = mustBreakForReturnType(Line);
 
     Current->CanBreakBefore =
         Current->MustBreakBefore || canBreakBefore(Line, *Current);
diff --git a/clang/lib/Format/TokenAnnotator.h b/clang/lib/Format/TokenAnnotator.h
index b8a6be057a6..5329f1f3f2f 100644
--- a/clang/lib/Format/TokenAnnotator.h
+++ b/clang/lib/Format/TokenAnnotator.h
@@ -86,6 +86,15 @@ public:
     return startsWith(First, Tokens...);
   }
 
+  /// \c true if this line looks like a function definition instead of a
+  /// function declaration. Asserts MightBeFunctionDecl.
+  bool mightBeFunctionDefinition() const {
+    assert(MightBeFunctionDecl);
+    // FIXME: Line.Last points to other characters than tok::semi
+    // and tok::lbrace.
+    return !Last->isOneOf(tok::semi, tok::comment);
+  }
+
   FormatToken *First;
   FormatToken *Last;
 
@@ -156,6 +165,8 @@ private:
 
   bool canBreakBefore(const AnnotatedLine &Line, const FormatToken &Right);
 
+  bool mustBreakForReturnType(const AnnotatedLine &Line) const;
+
   void printDebugInfo(const AnnotatedLine &Line);
 
   void calculateUnbreakableTailLengths(AnnotatedLine &Line);