clang-format: Add option to break after definition return type for top-level functions only

Differential Revision: http://reviews.llvm.org/D10774

6 files changed, 85 insertions, 25 deletions

diff --git a/clang/docs/ClangFormatStyleOptions.rst b/clang/docs/ClangFormatStyleOptions.rst
index 837d184a959..ab7bd872ca2 100644
--- a/clang/docs/ClangFormatStyleOptions.rst
+++ b/clang/docs/ClangFormatStyleOptions.rst
@@ -218,12 +218,19 @@ the configuration (without a prefix: ``Auto``).
   If ``true``, ``while (true) continue;`` can be put on a
   single line.
 
-**AlwaysBreakAfterDefinitionReturnType** (``bool``)
-  If ``true``, always break after function definition return types.
+**AlwaysBreakAfterDefinitionReturnType** (``DefinitionReturnTypeBreakingStyle``)
+  The function definition return type breaking style to use.
+
+  Possible values:
+
+  * ``DRTBS_None`` (in configuration: ``None``)
+    Break after return type automatically.
+    ``PenaltyReturnTypeOnItsOwnLine`` is taken into account.
+  * ``DRTBS_All`` (in configuration: ``All``)
+    Always break after the return type.
+  * ``DRTBS_TopLevel`` (in configuration: ``TopLevel``)
+    Always break after the return types of top level functions.
 
-  More truthfully called 'break before the identifier following the type
-  in a function definition'. PenaltyReturnTypeOnItsOwnLine becomes
-  irrelevant.
 
 **AlwaysBreakBeforeMultilineStrings** (``bool``)
   If ``true``, always break before multiline string literals.
diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index 66097e0dd50..6f9523cdc1b 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -112,12 +112,19 @@ struct FormatStyle {
   /// single line.
   bool AllowShortLoopsOnASingleLine;
 
-  /// \brief If \c true, always break after function definition return types.
-  ///
-  /// More truthfully called 'break before the identifier following the type
-  /// in a function definition'. PenaltyReturnTypeOnItsOwnLine becomes
-  /// irrelevant.
-  bool AlwaysBreakAfterDefinitionReturnType;
+  /// \brief Different ways to break after the function definition return type.
+  enum DefinitionReturnTypeBreakingStyle {
+    /// Break after return type automatically.
+    /// \c PenaltyReturnTypeOnItsOwnLine is taken into account.
+    DRTBS_None,
+    /// Always break after the return type.
+    DRTBS_All,
+    /// Always break after the return types of top level functions.
+    DRTBS_TopLevel,
+  };
+
+  /// \brief The function definition return type breaking style to use.
+  DefinitionReturnTypeBreakingStyle AlwaysBreakAfterDefinitionReturnType;
 
   /// \brief If \c true, always break before multiline string literals.
   ///
diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index 2717c2731d2..ed01d689c59 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -126,7 +126,8 @@ 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 && State.Column < 6)
+      Style.AlwaysBreakAfterDefinitionReturnType == FormatStyle::DRTBS_None &&
+      State.Column < 6)
     return false;
 
   return !State.Stack.back().NoLineBreak;
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index edc44d3e3df..0dd7ca0cbc1 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -99,6 +99,18 @@ template <> struct ScalarEnumerationTraits<FormatStyle::BraceBreakingStyle> {
   }
 };
 
+template <> struct ScalarEnumerationTraits<FormatStyle::DefinitionReturnTypeBreakingStyle> {
+  static void enumeration(IO &IO, FormatStyle::DefinitionReturnTypeBreakingStyle &Value) {
+    IO.enumCase(Value, "None", FormatStyle::DRTBS_None);
+    IO.enumCase(Value, "All", FormatStyle::DRTBS_All);
+    IO.enumCase(Value, "TopLevel", FormatStyle::DRTBS_TopLevel);
+
+    // For backward compatibility.
+    IO.enumCase(Value, "false", FormatStyle::DRTBS_None);
+    IO.enumCase(Value, "true", FormatStyle::DRTBS_All);
+  }
+};
+
 template <>
 struct ScalarEnumerationTraits<FormatStyle::NamespaceIndentationKind> {
   static void enumeration(IO &IO,
@@ -338,7 +350,7 @@ FormatStyle getLLVMStyle() {
   LLVMStyle.AllowShortCaseLabelsOnASingleLine = false;
   LLVMStyle.AllowShortIfStatementsOnASingleLine = false;
   LLVMStyle.AllowShortLoopsOnASingleLine = false;
-  LLVMStyle.AlwaysBreakAfterDefinitionReturnType = false;
+  LLVMStyle.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_None;
   LLVMStyle.AlwaysBreakBeforeMultilineStrings = false;
   LLVMStyle.AlwaysBreakTemplateDeclarations = false;
   LLVMStyle.BinPackParameters = true;
@@ -463,6 +475,8 @@ FormatStyle getMozillaStyle() {
   FormatStyle MozillaStyle = getLLVMStyle();
   MozillaStyle.AllowAllParametersOfDeclarationOnNextLine = false;
   MozillaStyle.AllowShortFunctionsOnASingleLine = FormatStyle::SFS_Inline;
+  MozillaStyle.AlwaysBreakAfterDefinitionReturnType =
+      FormatStyle::DRTBS_TopLevel;
   MozillaStyle.AlwaysBreakTemplateDeclarations = true;
   MozillaStyle.BreakConstructorInitializersBeforeComma = true;
   MozillaStyle.ConstructorInitializerIndentWidth = 2;
@@ -498,7 +512,7 @@ FormatStyle getWebKitStyle() {
 
 FormatStyle getGNUStyle() {
   FormatStyle Style = getLLVMStyle();
-  Style.AlwaysBreakAfterDefinitionReturnType = true;
+  Style.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_All;
   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 2f1aae39344..0117f222004 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1539,8 +1539,11 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
     Current->MustBreakBefore =
         Current->MustBreakBefore || mustBreakBefore(Line, *Current);
 
-    if (Style.AlwaysBreakAfterDefinitionReturnType && InFunctionDecl &&
-        Current->is(TT_FunctionDeclarationName) &&
+    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.
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 6b8bff167ab..743171fb003 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -4618,30 +4618,50 @@ TEST_F(FormatTest, AlignsStringLiterals) {
                "              \"c\";");
 }
 
-TEST_F(FormatTest, AlwaysBreakAfterDefinitionReturnType) {
-  FormatStyle AfterType = getLLVMStyle();
-  AfterType.AlwaysBreakAfterDefinitionReturnType = true;
+TEST_F(FormatTest, DefinitionReturnTypeBreakingStyle) {
+  FormatStyle Style = getLLVMStyle();
+  Style.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_TopLevel;
+  verifyFormat("class C {\n"
+               "  int f() { return 1; }\n"
+               "};\n"
+               "int\n"
+               "f() {\n"
+               "  return 1;\n"
+               "}",
+               Style);
+  Style.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_All;
+  verifyFormat("class C {\n"
+               "  int\n"
+               "  f() {\n"
+               "    return 1;\n"
+               "  }\n"
+               "};\n"
+               "int\n"
+               "f() {\n"
+               "  return 1;\n"
+               "}",
+               Style);
   verifyFormat("const char *\n"
                "f(void) {\n" // Break here.
                "  return \"\";\n"
                "}\n"
                "const char *bar(void);\n", // No break here.
-               AfterType);
+               Style);
   verifyFormat("template <class T>\n"
                "T *\n"
                "f(T &c) {\n" // Break here.
                "  return NULL;\n"
                "}\n"
                "template <class T> T *f(T &c);\n", // No break here.
-               AfterType);
-  AfterType.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
+               Style);
+  Style.BreakBeforeBraces = FormatStyle::BS_Stroustrup;
   verifyFormat("const char *\n"
                "f(void)\n" // Break here.
                "{\n"
                "  return \"\";\n"
                "}\n"
                "const char *bar(void);\n", // No break here.
-               AfterType);
+               Style);
   verifyFormat("template <class T>\n"
                "T *\n"     // Problem here: no line break
                "f(T &c)\n" // Break here.
@@ -4649,7 +4669,7 @@ TEST_F(FormatTest, AlwaysBreakAfterDefinitionReturnType) {
                "  return NULL;\n"
                "}\n"
                "template <class T> T *f(T &c);\n", // No break here.
-               AfterType);
+               Style);
 }
 
 TEST_F(FormatTest, AlwaysBreakBeforeMultilineStrings) {
@@ -9041,7 +9061,6 @@ TEST_F(FormatTest, ParsesConfigurationBools) {
   CHECK_PARSE_BOOL(AllowShortCaseLabelsOnASingleLine);
   CHECK_PARSE_BOOL(AllowShortIfStatementsOnASingleLine);
   CHECK_PARSE_BOOL(AllowShortLoopsOnASingleLine);
-  CHECK_PARSE_BOOL(AlwaysBreakAfterDefinitionReturnType);
   CHECK_PARSE_BOOL(AlwaysBreakTemplateDeclarations);
   CHECK_PARSE_BOOL(BinPackParameters);
   CHECK_PARSE_BOOL(BinPackArguments);
@@ -9174,6 +9193,15 @@ TEST_F(FormatTest, ParsesConfiguration) {
               FormatStyle::BS_Allman);
   CHECK_PARSE("BreakBeforeBraces: GNU", BreakBeforeBraces, FormatStyle::BS_GNU);
 
+  Style.AlwaysBreakAfterDefinitionReturnType = FormatStyle::DRTBS_All;
+  CHECK_PARSE("AlwaysBreakAfterDefinitionReturnType: None",
+              AlwaysBreakAfterDefinitionReturnType, FormatStyle::DRTBS_None);
+  CHECK_PARSE("AlwaysBreakAfterDefinitionReturnType: All",
+              AlwaysBreakAfterDefinitionReturnType, FormatStyle::DRTBS_All);
+  CHECK_PARSE("AlwaysBreakAfterDefinitionReturnType: TopLevel",
+              AlwaysBreakAfterDefinitionReturnType,
+              FormatStyle::DRTBS_TopLevel);
+
   Style.NamespaceIndentation = FormatStyle::NI_All;
   CHECK_PARSE("NamespaceIndentation: None", NamespaceIndentation,
               FormatStyle::NI_None);