[clang-format][NFC] Annotate attribute squares more effectively #164052

owenca · 2025-10-18T06:25:24Z

Annotate left/right attribute squares distinctively and only annotate the outer pair of C++ attribute squares.

llvmbot · 2025-10-18T06:25:58Z

@llvm/pr-subscribers-clang-format

Author: owenca (owenca)

Changes

Annotate left/right attribute squares distinctively and only annotate the outer pair of C++ attribute squares.

Full diff: https://github.com/llvm/llvm-project/pull/164052.diff

5 Files Affected:

(modified) clang/lib/Format/ContinuationIndenter.cpp (+7-5)
(modified) clang/lib/Format/DefinitionBlockSeparator.cpp (+1-1)
(modified) clang/lib/Format/FormatToken.h (+2-1)
(modified) clang/lib/Format/TokenAnnotator.cpp (+30-30)
(modified) clang/unittests/Format/TokenAnnotatorTest.cpp (+23)

diff --git a/clang/lib/Format/ContinuationIndenter.cpp b/clang/lib/Format/ContinuationIndenter.cpp
index cd4c1aabac971..d5e3765c9341f 100644
--- a/clang/lib/Format/ContinuationIndenter.cpp
+++ b/clang/lib/Format/ContinuationIndenter.cpp
@@ -433,7 +433,7 @@ bool ContinuationIndenter::mustBreak(const LineState &State) {
   }
   if ((startsNextParameter(Current, Style) || Previous.is(tok::semi) ||
        (Previous.is(TT_TemplateCloser) && Current.is(TT_StartOfName) &&
-        State.Line->First->isNot(TT_AttributeSquare) && Style.isCpp() &&
+        State.Line->First->isNot(TT_AttributeLSquare) && Style.isCpp() &&
         // FIXME: This is a temporary workaround for the case where clang-format
         // sets BreakBeforeParameter to avoid bin packing and this creates a
         // completely unnecessary line break after a template type that isn't
@@ -1369,7 +1369,8 @@ unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
   }
   if (Current.is(TT_LambdaArrow) &&
       Previous.isOneOf(tok::kw_noexcept, tok::kw_mutable, tok::kw_constexpr,
-                       tok::kw_consteval, tok::kw_static, TT_AttributeSquare)) {
+                       tok::kw_consteval, tok::kw_static,
+                       TT_AttributeRSquare)) {
     return ContinuationIndent;
   }
   if ((Current.isOneOf(tok::r_brace, tok::r_square) ||
@@ -1494,9 +1495,10 @@ unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
          Current.isNot(tok::l_paren) &&
          !Current.endsSequence(TT_StartOfName, TT_AttributeMacro,
                                TT_PointerOrReference)) ||
-        PreviousNonComment->isOneOf(
-            TT_AttributeRParen, TT_AttributeSquare, TT_FunctionAnnotationRParen,
-            TT_JavaAnnotation, TT_LeadingJavaAnnotation))) ||
+        PreviousNonComment->isOneOf(TT_AttributeRParen, TT_AttributeRSquare,
+                                    TT_FunctionAnnotationRParen,
+                                    TT_JavaAnnotation,
+                                    TT_LeadingJavaAnnotation))) ||
       (!Style.IndentWrappedFunctionNames &&
        NextNonComment->isOneOf(tok::kw_operator, TT_FunctionDeclarationName))) {
     return std::max(CurrentState.LastSpace, CurrentState.Indent);
diff --git a/clang/lib/Format/DefinitionBlockSeparator.cpp b/clang/lib/Format/DefinitionBlockSeparator.cpp
index 3f4ce5fa3a428..855f2efad1e53 100644
--- a/clang/lib/Format/DefinitionBlockSeparator.cpp
+++ b/clang/lib/Format/DefinitionBlockSeparator.cpp
@@ -169,7 +169,7 @@ void DefinitionBlockSeparator::separateBlocks(
         }
       }
 
-      if (Style.isCSharp() && OperateLine->First->is(TT_AttributeSquare))
+      if (Style.isCSharp() && OperateLine->First->is(TT_AttributeLSquare))
         return true;
       return false;
     };
diff --git a/clang/lib/Format/FormatToken.h b/clang/lib/Format/FormatToken.h
index f015d27bed6af..6f3d24aefc1ca 100644
--- a/clang/lib/Format/FormatToken.h
+++ b/clang/lib/Format/FormatToken.h
@@ -30,9 +30,10 @@ namespace format {
   TYPE(ArraySubscriptLSquare)                                                  \
   TYPE(AttributeColon)                                                         \
   TYPE(AttributeLParen)                                                        \
+  TYPE(AttributeLSquare)                                                       \
   TYPE(AttributeMacro)                                                         \
   TYPE(AttributeRParen)                                                        \
-  TYPE(AttributeSquare)                                                        \
+  TYPE(AttributeRSquare)                                                       \
   TYPE(BinaryOperator)                                                         \
   TYPE(BitFieldColon)                                                          \
   TYPE(BlockComment)                                                           \
diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 5b784eded4601..66e5a85941ba4 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -531,10 +531,6 @@ class AnnotatingParser {
             OpeningParen.Previous->is(TT_LeadingJavaAnnotation)) {
           CurrentToken->setType(TT_LeadingJavaAnnotation);
         }
-        if (OpeningParen.Previous &&
-            OpeningParen.Previous->is(TT_AttributeSquare)) {
-          CurrentToken->setType(TT_AttributeSquare);
-        }
 
         if (!HasMultipleLines)
           OpeningParen.setPackingKind(PPK_Inconclusive);
@@ -722,9 +718,11 @@ class AnnotatingParser {
       } else if (InsideInlineASM) {
         Left->setType(TT_InlineASMSymbolicNameLSquare);
       } else if (IsCpp11AttributeSpecifier) {
-        Left->setType(TT_AttributeSquare);
-        if (!IsInnerSquare && Left->Previous)
-          Left->Previous->EndsCppAttributeGroup = false;
+        if (!IsInnerSquare) {
+          Left->setType(TT_AttributeLSquare);
+          if (Left->Previous)
+            Left->Previous->EndsCppAttributeGroup = false;
+        }
       } else if (Style.isJavaScript() && Parent &&
                  Contexts.back().ContextKind == tok::l_brace &&
                  Parent->isOneOf(tok::l_brace, tok::comma)) {
@@ -733,7 +731,7 @@ class AnnotatingParser {
                  Parent && Parent->isOneOf(tok::l_brace, tok::comma)) {
         Left->setType(TT_DesignatedInitializerLSquare);
       } else if (IsCSharpAttributeSpecifier) {
-        Left->setType(TT_AttributeSquare);
+        Left->setType(TT_AttributeLSquare);
       } else if (CurrentToken->is(tok::r_square) && Parent &&
                  Parent->is(TT_TemplateCloser)) {
         Left->setType(TT_ArraySubscriptLSquare);
@@ -797,13 +795,12 @@ class AnnotatingParser {
 
     while (CurrentToken) {
       if (CurrentToken->is(tok::r_square)) {
-        if (IsCpp11AttributeSpecifier) {
-          CurrentToken->setType(TT_AttributeSquare);
-          if (!IsInnerSquare)
-            CurrentToken->EndsCppAttributeGroup = true;
+        if (IsCpp11AttributeSpecifier && !IsInnerSquare) {
+          CurrentToken->setType(TT_AttributeRSquare);
+          CurrentToken->EndsCppAttributeGroup = true;
         }
         if (IsCSharpAttributeSpecifier) {
-          CurrentToken->setType(TT_AttributeSquare);
+          CurrentToken->setType(TT_AttributeRSquare);
         } else if (((CurrentToken->Next &&
                      CurrentToken->Next->is(tok::l_paren)) ||
                     (CurrentToken->Previous &&
@@ -1297,7 +1294,7 @@ class AnnotatingParser {
   bool consumeToken() {
     if (IsCpp) {
       const auto *Prev = CurrentToken->getPreviousNonComment();
-      if (Prev && Prev->is(tok::r_square) && Prev->is(TT_AttributeSquare) &&
+      if (Prev && Prev->is(TT_AttributeRSquare) &&
           CurrentToken->isOneOf(tok::kw_if, tok::kw_switch, tok::kw_case,
                                 tok::kw_default, tok::kw_for, tok::kw_while) &&
           mustBreakAfterAttributes(*CurrentToken, Style)) {
@@ -2850,7 +2847,7 @@ class AnnotatingParser {
             T = Tok->Previous;
             continue;
           }
-        } else if (T->is(TT_AttributeSquare)) {
+        } else if (T->is(TT_AttributeRSquare)) {
           // Handle `x = (foo *[[clang::foo]])&v;`:
           if (T->MatchingParen && T->MatchingParen->Previous) {
             T = T->MatchingParen->Previous;
@@ -3656,7 +3653,7 @@ static FormatToken *getFunctionName(const AnnotatedLine &Line,
   for (FormatToken *Tok = Line.getFirstNonComment(), *Name = nullptr; Tok;
        Tok = Tok->getNextNonComment()) {
     // Skip C++11 attributes both before and after the function name.
-    if (Tok->is(tok::l_square) && Tok->is(TT_AttributeSquare)) {
+    if (Tok->is(TT_AttributeLSquare)) {
       Tok = Tok->MatchingParen;
       if (!Tok)
         break;
@@ -4328,7 +4325,7 @@ unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
       return 35;
     if (Right.isNoneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
                        TT_ArrayInitializerLSquare,
-                       TT_DesignatedInitializerLSquare, TT_AttributeSquare)) {
+                       TT_DesignatedInitializerLSquare, TT_AttributeLSquare)) {
       return 500;
     }
   }
@@ -4808,7 +4805,7 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
   if (Right.is(tok::l_square) &&
       Right.isNoneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
                      TT_DesignatedInitializerLSquare,
-                     TT_StructuredBindingLSquare, TT_AttributeSquare) &&
+                     TT_StructuredBindingLSquare, TT_AttributeLSquare) &&
       Left.isNoneOf(tok::numeric_constant, TT_DictLiteral) &&
       !(Left.isNot(tok::r_square) && Style.SpaceBeforeSquareBrackets &&
         Right.is(TT_ArraySubscriptLSquare))) {
@@ -4826,7 +4823,7 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
 
   // Space between template and attribute.
   // e.g. template <typename T> [[nodiscard]] ...
-  if (Left.is(TT_TemplateCloser) && Right.is(TT_AttributeSquare))
+  if (Left.is(TT_TemplateCloser) && Right.is(TT_AttributeLSquare))
     return true;
   // Space before parentheses common for all languages
   if (Right.is(tok::l_paren)) {
@@ -4841,10 +4838,8 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
       return Style.SpaceBeforeParensOptions.AfterRequiresInExpression ||
              spaceRequiredBeforeParens(Right);
     }
-    if (Left.is(TT_AttributeRParen) ||
-        (Left.is(tok::r_square) && Left.is(TT_AttributeSquare))) {
+    if (Left.isOneOf(TT_AttributeRParen, TT_AttributeRSquare))
       return true;
-    }
     if (Left.is(TT_ForEachMacro)) {
       return Style.SpaceBeforeParensOptions.AfterForeachMacros ||
              spaceRequiredBeforeParens(Right);
@@ -5662,16 +5657,14 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
     }
 
     // Break after C# [...] and before public/protected/private/internal.
-    if (Left.is(TT_AttributeSquare) && Left.is(tok::r_square) &&
+    if (Left.is(TT_AttributeRSquare) &&
         (Right.isAccessSpecifier(/*ColonRequired=*/false) ||
          Right.is(Keywords.kw_internal))) {
       return true;
     }
     // Break between ] and [ but only when there are really 2 attributes.
-    if (Left.is(TT_AttributeSquare) && Right.is(TT_AttributeSquare) &&
-        Left.is(tok::r_square) && Right.is(tok::l_square)) {
+    if (Left.is(TT_AttributeRSquare) && Right.is(TT_AttributeLSquare))
       return true;
-    }
   } else if (Style.isJavaScript()) {
     // FIXME: This might apply to other languages and token kinds.
     if (Right.is(tok::string_literal) && Left.is(tok::plus) && BeforeLeft &&
@@ -6090,6 +6083,11 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
       return true;
   }
 
+  if (Style.BreakAfterAttributes == FormatStyle::ABS_Leave &&
+      Left.is(TT_AttributeRSquare) && Right.NewlinesBefore > 0) {
+    return true;
+  }
+
   return false;
 }
 
@@ -6411,8 +6409,10 @@ bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
   if (Right.isAttribute())
     return true;
 
-  if (Right.is(tok::l_square) && Right.is(TT_AttributeSquare))
-    return Left.isNot(TT_AttributeSquare);
+  if (Right.is(TT_AttributeLSquare)) {
+    assert(Left.isNot(tok::l_square));
+    return true;
+  }
 
   if (Left.is(tok::identifier) && Right.is(tok::string_literal))
     return true;
@@ -6453,8 +6453,8 @@ bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
        Left.getPrecedence() == prec::Assignment)) {
     return true;
   }
-  if ((Left.is(TT_AttributeSquare) && Right.is(tok::l_square)) ||
-      (Left.is(tok::r_square) && Right.is(TT_AttributeSquare))) {
+  if (Left.is(tok::r_square) && Right.is(TT_AttributeRSquare)) {
+    assert(Left.isNot(TT_AttributeRSquare));
     return false;
   }
 
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 1152466b0179f..f3637383a0a65 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -4232,6 +4232,29 @@ TEST_F(TokenAnnotatorTest, QtProperty) {
   EXPECT_TOKEN(Tokens[12], tok::identifier, TT_QtProperty);
 }
 
+TEST_F(TokenAnnotatorTest, AttributeSquares) {
+  auto Tokens = annotate("[[maybe_unused]] const int i;");
+  ASSERT_EQ(Tokens.size(), 10u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::l_square, TT_AttributeLSquare);
+  EXPECT_TOKEN(Tokens[1], tok::l_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[3], tok::r_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[4], tok::r_square, TT_AttributeRSquare);
+  EXPECT_TRUE(Tokens[4]->EndsCppAttributeGroup);
+
+  Tokens = annotate("[[foo([[]])]] [[maybe_unused]] int j;");
+  ASSERT_EQ(Tokens.size(), 20u) << Tokens;
+  EXPECT_TOKEN(Tokens[0], tok::l_square, TT_AttributeLSquare);
+  EXPECT_TOKEN(Tokens[1], tok::l_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[9], tok::r_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[10], tok::r_square, TT_AttributeRSquare);
+  EXPECT_FALSE(Tokens[10]->EndsCppAttributeGroup);
+  EXPECT_TOKEN(Tokens[11], tok::l_square, TT_AttributeLSquare);
+  EXPECT_TOKEN(Tokens[12], tok::l_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[14], tok::r_square, TT_Unknown);
+  EXPECT_TOKEN(Tokens[15], tok::r_square, TT_AttributeRSquare);
+  EXPECT_TRUE(Tokens[15]->EndsCppAttributeGroup);
+}
+
 } // namespace
 } // namespace format
 } // namespace clang

clang/lib/Format/TokenAnnotator.cpp

[clang-format][NFC] Annotate attribute squares more effectively

ea15af3

Annotate left/right attribute squares distinctively and only annotate the outer pair of C++ attribute squares.

llvmbot added the clang-format label Oct 18, 2025

HazardyKnusperkeks approved these changes Oct 18, 2025

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owenca commented Oct 18, 2025

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Update clang/lib/Format/TokenAnnotator.cpp

9597728

HazardyKnusperkeks approved these changes Oct 18, 2025

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owenca commented Oct 19, 2025

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clang/lib/Format/TokenAnnotator.cpp Show resolved Hide resolved

Update clang/lib/Format/TokenAnnotator.cpp

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HazardyKnusperkeks approved these changes Oct 19, 2025

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owenca merged commit f072036 into llvm:main Oct 19, 2025
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owenca deleted the attribute-squares branch October 19, 2025 18:38

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