[clang-tools-extra] [clang-tidy] Replace /* ... */ single-line comments with // ... comments (PR #124319)
via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 24 10:02:32 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-tools-extra
Author: None (4m4n-x-B4w4ne)
<details>
<summary>Changes</summary>
This Pull Request is to fix issue #<!-- -->24841.
I am also cherry-pick commit a3c7fca28faee679a59afd58c2e814025771ff63.
@<!-- -->LegalizeAdulthood @<!-- -->PiotrZSL
---
Full diff: https://github.com/llvm/llvm-project/pull/124319.diff
7 Files Affected:
- (modified) clang-tools-extra/clang-tidy/modernize/CMakeLists.txt (+1)
- (modified) clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp (+3)
- (added) clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.cpp (+126)
- (added) clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.h (+40)
- (modified) clang-tools-extra/docs/ReleaseNotes.rst (+5)
- (added) clang-tools-extra/docs/clang-tidy/checks/modernize/use-cpp-style-comments.rst (+38)
- (added) clang-tools-extra/test/clang-tidy/checkers/modernize/use-cpp-style-comments.cpp (+68)
``````````diff
diff --git a/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt b/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
index bab1167fb15ff2..f07dd5efecc58e 100644
--- a/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
+++ b/clang-tools-extra/clang-tidy/modernize/CMakeLists.txt
@@ -31,6 +31,7 @@ add_clang_library(clangTidyModernizeModule STATIC
UseAutoCheck.cpp
UseBoolLiteralsCheck.cpp
UseConstraintsCheck.cpp
+ UseCppStyleCommentsCheck.cpp
UseDefaultMemberInitCheck.cpp
UseDesignatedInitializersCheck.cpp
UseEmplaceCheck.cpp
diff --git a/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp b/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
index fc46c72982fdce..1917d562f7ce8d 100644
--- a/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/ModernizeTidyModule.cpp
@@ -32,6 +32,7 @@
#include "UseAutoCheck.h"
#include "UseBoolLiteralsCheck.h"
#include "UseConstraintsCheck.h"
+#include "UseCppStyleCommentsCheck.h"
#include "UseDefaultMemberInitCheck.h"
#include "UseDesignatedInitializersCheck.h"
#include "UseEmplaceCheck.h"
@@ -107,6 +108,8 @@ class ModernizeModule : public ClangTidyModule {
"modernize-use-bool-literals");
CheckFactories.registerCheck<UseConstraintsCheck>(
"modernize-use-constraints");
+ CheckFactories.registerCheck<UseCppStyleCommentsCheck>(
+ "modernize-use-cpp-style-comments");
CheckFactories.registerCheck<UseDefaultMemberInitCheck>(
"modernize-use-default-member-init");
CheckFactories.registerCheck<UseEmplaceCheck>("modernize-use-emplace");
diff --git a/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.cpp b/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.cpp
new file mode 100644
index 00000000000000..3c25c50bab759c
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.cpp
@@ -0,0 +1,126 @@
+//===--- UseCppStyleCommentsCheck.cpp - clang-tidy-------------------------===//
+
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "UseCppStyleCommentsCheck.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+#include "clang/Lex/Lexer.h"
+#include "clang/Lex/Preprocessor.h"
+#include <iostream>
+using namespace clang::ast_matchers;
+
+namespace clang::tidy::modernize {
+class UseCppStyleCommentsCheck::CStyleCommentHandler : public CommentHandler {
+public:
+ CStyleCommentHandler(UseCppStyleCommentsCheck &Check)
+ : Check(Check),
+ CStyleCommentMatch(
+ "^[ \t]*/\\*+[ \t\r\n]*(.*[ \t\r\n]*)*[ \t\r\n]*\\*+/[ \t\r\n]*$"){}
+
+ std::string convertToCppStyleComment(const SourceManager &SM, const SourceRange &Range) {
+ StringRef CommentText = Lexer::getSourceText(
+ CharSourceRange::getTokenRange(Range), SM, LangOptions());
+
+ std::string InnerText = CommentText.str();
+ InnerText.erase(0, 2);
+ InnerText.erase(InnerText.size() - 2, 2);
+
+ std::string Result;
+ std::istringstream Stream(InnerText);
+ std::string Line;
+
+ if (std::getline(Stream, Line)) {
+ size_t startPos = Line.find_first_not_of(" \t");
+ if (startPos != std::string::npos) {
+ Line = Line.substr(startPos);
+ } else {
+ Line.clear();
+ }
+ Result += "// " + Line;
+ }
+
+ while (std::getline(Stream, Line)) {
+ size_t startPos = Line.find_first_not_of(" \t");
+ if (startPos != std::string::npos) {
+ Line = Line.substr(startPos);
+ } else {
+ Line.clear();
+ }
+ Result += "\n// " + Line;
+ }
+ return Result;
+ }
+
+ bool HandleComment(Preprocessor &PP, SourceRange Range) override {
+ const SourceManager &SM = PP.getSourceManager();
+
+ if (Range.getBegin().isMacroID() ||
+ SM.isInSystemHeader(Range.getBegin())) {
+ return false;
+ }
+
+ const StringRef Text =
+ Lexer::getSourceText(CharSourceRange::getCharRange(Range),
+ SM, PP.getLangOpts());
+
+ SmallVector<StringRef> Matches;
+ if (!CStyleCommentMatch.match(Text, &Matches)) {
+ return false;
+ }
+
+ SourceLocation CommentStart = Range.getBegin();
+ SourceLocation CommentEnd = Range.getEnd();
+
+ unsigned StartLine = SM.getSpellingLineNumber(CommentStart);
+ unsigned EndLine = SM.getSpellingLineNumber(CommentEnd);
+
+
+ if (StartLine == EndLine) {
+ SourceLocation LineBegin = SM.translateLineCol(
+ SM.getFileID(CommentStart), StartLine, 1);
+ SourceLocation LineEnd = SM.translateLineCol(SM.getFileID(CommentEnd), EndLine, std::numeric_limits<unsigned>::max());
+ StringRef LineContent =
+ Lexer::getSourceText(CharSourceRange::getCharRange(LineBegin, LineEnd),
+ SM, PP.getLangOpts());
+ size_t CommentStartOffset = SM.getSpellingColumnNumber(CommentStart) - 1;
+ StringRef AfterComment = LineContent.drop_front(CommentStartOffset + Text.size());
+
+ if (!AfterComment.trim().empty()) {
+ return false;
+ }
+ }
+
+ Check.diag(
+ Range.getBegin(),
+ "use C++ style comments '//' instead of C style comments '/*...*/'")
+ << clang::FixItHint::CreateReplacement(
+ Range, convertToCppStyleComment(SM, Range));
+
+ return false;
+}
+
+
+private:
+ UseCppStyleCommentsCheck &Check;
+ llvm::Regex CStyleCommentMatch;
+};
+
+UseCppStyleCommentsCheck::UseCppStyleCommentsCheck(StringRef Name,
+ ClangTidyContext *Context)
+ : ClangTidyCheck(Name, Context),
+ Handler(std::make_unique<CStyleCommentHandler>(*this)) {}
+
+void UseCppStyleCommentsCheck::registerPPCallbacks(
+ const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
+ PP->addCommentHandler(Handler.get());
+}
+
+void UseCppStyleCommentsCheck::check(const MatchFinder::MatchResult &Result) {}
+
+UseCppStyleCommentsCheck::~UseCppStyleCommentsCheck() = default;
+} // namespace clang::tidy::modernize
diff --git a/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.h b/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.h
new file mode 100644
index 00000000000000..3d604683de5a24
--- /dev/null
+++ b/clang-tools-extra/clang-tidy/modernize/UseCppStyleCommentsCheck.h
@@ -0,0 +1,40 @@
+//===--- UseCppStyleCommentsCheck.h - clang-tidy---------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_CPP_STYLE_COMMENTS_CHECK_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_CPP_STYLE_COMMENTS_CHECK_H
+
+#include "../ClangTidyCheck.h"
+#include <sstream>
+namespace clang::tidy::modernize {
+/// Detects C Style comments and suggests to use C++ style comments instead.
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/modernize/use-cpp-style-comments.html
+class UseCppStyleCommentsCheck : public ClangTidyCheck {
+public:
+ UseCppStyleCommentsCheck(StringRef Name, ClangTidyContext *Context);
+
+ ~UseCppStyleCommentsCheck() override;
+
+ bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
+ return LangOpts.CPlusPlus;
+ }
+
+ void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
+ Preprocessor *ModuleExpanderPP) override;
+
+ void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+
+private:
+ class CStyleCommentHandler;
+ std::unique_ptr<CStyleCommentHandler> Handler;
+};
+} // namespace clang::tidy::modernize
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_CPP_STYLE_COMMENTS_CHECK_H
diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index cc5f64a3f9fa32..a89cd1a8b80e50 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -173,6 +173,11 @@ New checks
Replace comparisons between signed and unsigned integers with their safe
C++20 ``std::cmp_*`` alternative, if available.
+
+- New :doc:`modernize-use-cpp-style-comments
+ <clang-tidy/checks/modernize/use-cpp-style-comments>` check.
+
+ Detects C Style comments and suggests to use C++ style comments instead.
- New :doc:`portability-template-virtual-member-function
<clang-tidy/checks/portability/template-virtual-member-function>` check.
diff --git a/clang-tools-extra/docs/clang-tidy/checks/modernize/use-cpp-style-comments.rst b/clang-tools-extra/docs/clang-tidy/checks/modernize/use-cpp-style-comments.rst
new file mode 100644
index 00000000000000..5eaf759a3db6d6
--- /dev/null
+++ b/clang-tools-extra/docs/clang-tidy/checks/modernize/use-cpp-style-comments.rst
@@ -0,0 +1,38 @@
+.. title:: clang-tidy - use-cpp-style-comments
+
+modernize-use-cpp-style-comments
+=======================
+
+Replace C-style comments with C++-style comments.
+C-style comments (`/* ... */`) are inherited from C, while C++ introduces
+`//` as a more concise, readable, and less error-prone alternative. Modern C++
+guidelines recommend using C++-style comments for consistency and
+maintainability. This check identifies and replaces C-style comments with
+equivalent C++-style comments.
+
+Examples:
+
+Input:
+.. code-block::c++
+ /* This is a single-line comment */
+ int x = 42; /* Inline comment */
+
+ /* This is a
+ multi-line comment */
+
+
+Output:
+.. code-block::c++
+ // This is a single-line comment
+ int x = 42; // Inline comment
+
+ // This is a
+ // multi-line comment
+
+.. note::
+
+ Inline Comments are neither fixed nor warned.
+ Example:
+ .. code-block:: c++
+ int a = /* this is a comment */ 5;
+
diff --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/use-cpp-style-comments.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-cpp-style-comments.cpp
new file mode 100644
index 00000000000000..f56750591e035f
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/use-cpp-style-comments.cpp
@@ -0,0 +1,68 @@
+// RUN: %check_clang_tidy -std=c++11 %s modernize-use-cpp-style-comments %t -- --
+
+// Single-line full C-style comment
+static const int CONSTANT = 42; /* Important constant value */
+// CHECK-MESSAGES: :[[@LINE-1]]:33: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+// CHECK-FIXES: static const int CONSTANT = 42; // Important constant value
+
+// Inline comment that should NOT be transformed
+int a = /* inline comment */ 5;
+
+// Multiline full-line comment
+/* This is a multiline comment
+ that spans several lines
+ and should be converted to C++ style */
+// CHECK-MESSAGES: :[[@LINE-3]]:1: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+// CHECK-FIXES: // This is a multiline comment
+// CHECK-FIXES: // that spans several lines
+// CHECK-FIXES: // and should be converted to C++ style
+void fnWithSomeBools(bool A,bool B) {}
+// Function with parameter inline comments
+void processData(int data /* input data */,
+ bool validate /* perform validation */) {
+ // These inline comments should NOT be transformed
+ fnWithSomeBools(/*ControlsA=*/ true, /*ControlsB=*/ false);
+}
+
+// Multiline comment with asterisk styling
+/*******************************
+ * Block comment with asterisks
+ * Should be converted to C++ style
+ *******************************/
+// CHECK-MESSAGES: :[[@LINE-4]]:1: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+// CHECK-FIXES: // ******************************
+// CHECK-FIXES: // * Block comment with asterisks
+// CHECK-FIXES: // * Should be converted to C++ style
+// CHECK-FIXES: // ******************************
+int calculateSomething() { return 1;}
+// Comment at end of complex line
+int complexCalculation = calculateSomething(); /* Result of complex calculation */
+// CHECK-MESSAGES: :[[@LINE-1]]:48: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+// CHECK-FIXES: int complexCalculation = calculateSomething(); // Result of complex calculation
+
+// Nested comments and edge cases
+void edgeCaseFunction() {
+ int x = 10 /* First value */ + 20 /* Second value */; // Inline comments should not transform
+
+ /* Comment with special characters !@#$%^&*()_+ */
+ // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+ // CHECK-FIXES: // Comment with special characters !@#$%^&*()_+
+}
+
+// Multiline comment with various indentations
+ /* This comment is indented
+ and should preserve indentation when converted */
+// CHECK-MESSAGES: :[[@LINE-2]]:5: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+// CHECK-FIXES: // This comment is indented
+// CHECK-FIXES: // and should preserve indentation when converted
+
+// Complex function with mixed comment types
+void complexFunction() {
+ /* Full line comment at start of block */
+ // CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+ // CHECK-FIXES: // Full line comment at start of block
+
+ int x = 10; /* Inline comment not to be transformed */
+ // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: use C++ style comments '//' instead of C style comments '/*...*/' [modernize-use-cpp-style-comments]
+ // CHECK-FIXES: int x = 10; // Inline comment not to be transformed
+}
\ No newline at end of file
``````````
</details>
https://github.com/llvm/llvm-project/pull/124319
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