[clang-format] Add an option to add a space between operator overloading and opening parentheses

This change adds an option AfterOverloadedOperator in SpaceBeforeParensOptions to add a space between overloaded operator and opening parentheses in clang-format.

Reviewed By: MyDeveloperDay, curdeius, HazardyKnusperkeks

Differential Revision: https://reviews.llvm.org/D116283

clang/docs/ClangFormatStyleOptions.rst

@@ -3818,6 +3818,15 @@ the configuration (without a prefix: ``Auto``).
        IF (...)                        vs.    IF(...)
          <conditional-body>                     <conditional-body>
 
+  * ``bool AfterOverloadedOperator`` If ``true``, put a space between operator overloading and opening
+    parentheses.
+
+    .. code-block:: c++
+
+       true:                                  false:
+       void operator++ (int a);        vs.    void operator++(int a);
+       object.operator++ (10);                object.operator++(10);
+
   * ``bool BeforeNonEmptyParentheses`` If ``true``, put a space before opening parentheses only if the
     parentheses are not empty.
 

clang/docs/ReleaseNotes.rst

@@ -311,6 +311,9 @@ clang-format
 
 - Improved C++20 Modules and Coroutines support.
 
+- Option ``AfterOverloadedOperator`` has been added in ``SpaceBeforeParensOptions``
+  to allow space between overloaded operator and opening parentheses.
+
 libclang
 --------
 

clang/include/clang/Format/Format.h

@@ -3429,6 +3429,14 @@ struct FormatStyle {
     ///      <conditional-body>                     <conditional-body>
     /// \endcode
     bool AfterIfMacros;
+    /// If ``true``, put a space between operator overloading and opening
+    /// parentheses.
+    /// \code
+    ///    true:                                  false:
+    ///    void operator++ (int a);        vs.    void operator++(int a);
+    ///    object.operator++ (10);                object.operator++(10);
+    /// \endcode
+    bool AfterOverloadedOperator;
     /// If ``true``, put a space before opening parentheses only if the
     /// parentheses are not empty.
     /// \code
@@ -3442,7 +3450,7 @@ struct FormatStyle {
         : AfterControlStatements(false), AfterForeachMacros(false),
           AfterFunctionDeclarationName(false),
           AfterFunctionDefinitionName(false), AfterIfMacros(false),
-          BeforeNonEmptyParentheses(false) {}
+          AfterOverloadedOperator(false), BeforeNonEmptyParentheses(false) {}
 
     bool operator==(const SpaceBeforeParensCustom &Other) const {
       return AfterControlStatements == Other.AfterControlStatements &&
@@ -3451,6 +3459,7 @@ struct FormatStyle {
                  Other.AfterFunctionDeclarationName &&
              AfterFunctionDefinitionName == Other.AfterFunctionDefinitionName &&
              AfterIfMacros == Other.AfterIfMacros &&
+             AfterOverloadedOperator == Other.AfterOverloadedOperator &&
              BeforeNonEmptyParentheses == Other.BeforeNonEmptyParentheses;
     }
   };

clang/lib/Format/Format.cpp

@@ -868,6 +868,7 @@ template <> struct MappingTraits<FormatStyle::SpaceBeforeParensCustom> {
     IO.mapOptional("AfterFunctionDeclarationName",
                    Spacing.AfterFunctionDeclarationName);
     IO.mapOptional("AfterIfMacros", Spacing.AfterIfMacros);
+    IO.mapOptional("AfterOverloadedOperator", Spacing.AfterOverloadedOperator);
     IO.mapOptional("BeforeNonEmptyParentheses",
                    Spacing.BeforeNonEmptyParentheses);
   }

clang/lib/Format/TokenAnnotator.cpp

@@ -2923,9 +2923,15 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
 }
 
 bool TokenAnnotator::spaceRequiredBeforeParens(const FormatToken &Right) const {
-  return Style.SpaceBeforeParens == FormatStyle::SBPO_Always ||
-         (Style.SpaceBeforeParensOptions.BeforeNonEmptyParentheses &&
-          Right.ParameterCount > 0);
+  if (Style.SpaceBeforeParens == FormatStyle::SBPO_Always)
+    return true;
+  if (Right.is(TT_OverloadedOperatorLParen) &&
+      Style.SpaceBeforeParensOptions.AfterOverloadedOperator)
+    return true;
+  if (Style.SpaceBeforeParensOptions.BeforeNonEmptyParentheses &&
+      Right.ParameterCount > 0)
+    return true;
+  return false;
 }
 
 bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,

clang/unittests/Format/FormatTest.cpp

@@ -14536,6 +14536,24 @@ TEST_F(FormatTest, ConfigurableSpaceBeforeParens) {
   // verifyFormat("X A::operator++ (T);", SomeSpace2);
   verifyFormat("int x = int (y);", SomeSpace2);
   verifyFormat("auto lambda = []() { return 0; };", SomeSpace2);
+
+  FormatStyle SpaceAfterOverloadedOperator = getLLVMStyle();
+  SpaceAfterOverloadedOperator.SpaceBeforeParens = FormatStyle::SBPO_Custom;
+  SpaceAfterOverloadedOperator.SpaceBeforeParensOptions
+      .AfterOverloadedOperator = true;
+
+  verifyFormat("auto operator++ () -> int;", SpaceAfterOverloadedOperator);
+  verifyFormat("X A::operator++ ();", SpaceAfterOverloadedOperator);
+  verifyFormat("some_object.operator++ ();", SpaceAfterOverloadedOperator);
+  verifyFormat("auto func() -> int;", SpaceAfterOverloadedOperator);
+
+  SpaceAfterOverloadedOperator.SpaceBeforeParensOptions
+      .AfterOverloadedOperator = false;
+
+  verifyFormat("auto operator++() -> int;", SpaceAfterOverloadedOperator);
+  verifyFormat("X A::operator++();", SpaceAfterOverloadedOperator);
+  verifyFormat("some_object.operator++();", SpaceAfterOverloadedOperator);
+  verifyFormat("auto func() -> int;", SpaceAfterOverloadedOperator);
 }
 
 TEST_F(FormatTest, SpaceAfterLogicalNot) {
@@ -18771,6 +18789,15 @@ TEST_F(FormatTest, ParsesConfigurationBools) {
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, SplitEmptyFunction);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, SplitEmptyRecord);
   CHECK_PARSE_NESTED_BOOL(BraceWrapping, SplitEmptyNamespace);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions, AfterControlStatements);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions, AfterForeachMacros);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions,
+                          AfterFunctionDeclarationName);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions,
+                          AfterFunctionDefinitionName);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions, AfterIfMacros);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions, AfterOverloadedOperator);
+  CHECK_PARSE_NESTED_BOOL(SpaceBeforeParensOptions, BeforeNonEmptyParentheses);
 }
 
 #undef CHECK_PARSE_BOOL