llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-tools-extra Author: Vadim D. (vvd170501) <details> <summary>Changes</summary> This PR aims to expand the list of classes that are considered to be "strings" by `readability-string-compare` check. 1. Currently only `std::string;:compare` is checked, but `std::string_view` has a similar `compare` method. This PR enables checking of `std::string_view::compare` by default. 2. Some codebases use custom string-like classes that have public interfaces similar to `std::string` or `std::string_view`. Example: [TStringBase](https://github.com/yandex/yatool/blob/main/util/generic/strbase.h#L38), A new option, `readability-string-compare.StringClassNames`, is added to allow specifying a custom list of string-like classes. Related to, but does not solve #<!-- -->28396 (only adds support for custom string-like classes, not custom functions) --- Full diff: https://github.com/llvm/llvm-project/pull/88636.diff 7 Files Affected: - (modified) clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp (+51-23) - (modified) clang-tools-extra/clang-tidy/readability/StringCompareCheck.h (+7-2) - (modified) clang-tools-extra/docs/ReleaseNotes.rst (+5) - (modified) clang-tools-extra/docs/clang-tidy/checks/readability/string-compare.rst (+31-2) - (modified) clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string (+10) - (added) clang-tools-extra/test/clang-tidy/checkers/readability/string-compare-custom-string-classes.cpp (+38) - (modified) clang-tools-extra/test/clang-tidy/checkers/readability/string-compare.cpp (+23) ``````````diff diff --git a/clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp b/clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp index 3b5d89c8c64719..905e5b156ef864 100644 --- a/clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp +++ b/clang-tools-extra/clang-tidy/readability/StringCompareCheck.cpp @@ -7,12 +7,16 @@ //===----------------------------------------------------------------------===// #include "StringCompareCheck.h" -#include "../utils/FixItHintUtils.h" +#include "../utils/OptionsUtils.h" #include "clang/AST/ASTContext.h" #include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" #include "clang/Tooling/FixIt.h" +#include "llvm/ADT/StringRef.h" +#include <vector> using namespace clang::ast_matchers; +namespace optutils = clang::tidy::utils::options; namespace clang::tidy::readability { @@ -20,29 +24,53 @@ static const StringRef CompareMessage = "do not use 'compare' to test equality " "of strings; use the string equality " "operator instead"; +static const std::vector<StringRef> StringClasses = { + "::std::basic_string", "::std::basic_string_view"}; + +StringCompareCheck::StringCompareCheck(StringRef Name, + ClangTidyContext *Context) + : ClangTidyCheck(Name, Context), + StringLikeClasses( + optutils::parseStringList(Options.get("StringLikeClasses", ""))) {} + void StringCompareCheck::registerMatchers(MatchFinder *Finder) { - const auto StrCompare = cxxMemberCallExpr( - callee(cxxMethodDecl(hasName("compare"), - ofClass(classTemplateSpecializationDecl( - hasName("::std::basic_string"))))), - hasArgument(0, expr().bind("str2")), argumentCountIs(1), - callee(memberExpr().bind("str1"))); - - // First and second case: cast str.compare(str) to boolean. - Finder->addMatcher( - traverse(TK_AsIs, - implicitCastExpr(hasImplicitDestinationType(booleanType()), - has(StrCompare)) - .bind("match1")), - this); - - // Third and fourth case: str.compare(str) == 0 and str.compare(str) != 0. - Finder->addMatcher( - binaryOperator(hasAnyOperatorName("==", "!="), - hasOperands(StrCompare.bind("compare"), - integerLiteral(equals(0)).bind("zero"))) - .bind("match2"), - this); + const auto RegisterForClasses = [&, this](const auto &StringClassMatcher) { + const auto StrCompare = cxxMemberCallExpr( + callee(cxxMethodDecl(hasName("compare"), ofClass(StringClassMatcher))), + hasArgument(0, expr().bind("str2")), argumentCountIs(1), + callee(memberExpr().bind("str1"))); + + // First and second case: cast str.compare(str) to boolean. + Finder->addMatcher( + traverse(TK_AsIs, + implicitCastExpr(hasImplicitDestinationType(booleanType()), + has(StrCompare)) + .bind("match1")), + this); + + // Third and fourth case: str.compare(str) == 0 + // and str.compare(str) != 0. + Finder->addMatcher( + binaryOperator(hasAnyOperatorName("==", "!="), + hasOperands(StrCompare.bind("compare"), + integerLiteral(equals(0)).bind("zero"))) + .bind("match2"), + this); + }; + if (StringLikeClasses.empty()) { + RegisterForClasses( + classTemplateSpecializationDecl(hasAnyName(StringClasses))); + } else { + // StringLikeClasses may or may not be templates, so we need to match both + // template and non-template classes. + std::vector<StringRef> PossiblyTemplateClasses = StringClasses; + PossiblyTemplateClasses.insert(PossiblyTemplateClasses.end(), + StringLikeClasses.begin(), + StringLikeClasses.end()); + RegisterForClasses(anyOf( + classTemplateSpecializationDecl(hasAnyName(PossiblyTemplateClasses)), + cxxRecordDecl(hasAnyName(StringLikeClasses)))); + } } void StringCompareCheck::check(const MatchFinder::MatchResult &Result) { diff --git a/clang-tools-extra/clang-tidy/readability/StringCompareCheck.h b/clang-tools-extra/clang-tidy/readability/StringCompareCheck.h index 812736d806b71d..b7bb5a0097645b 100644 --- a/clang-tools-extra/clang-tidy/readability/StringCompareCheck.h +++ b/clang-tools-extra/clang-tidy/readability/StringCompareCheck.h @@ -10,6 +10,7 @@ #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_STRINGCOMPARECHECK_H #include "../ClangTidyCheck.h" +#include <vector> namespace clang::tidy::readability { @@ -20,13 +21,17 @@ namespace clang::tidy::readability { /// http://clang.llvm.org/extra/clang-tidy/checks/readability/string-compare.html class StringCompareCheck : public ClangTidyCheck { public: - StringCompareCheck(StringRef Name, ClangTidyContext *Context) - : ClangTidyCheck(Name, Context) {} + StringCompareCheck(StringRef Name, ClangTidyContext *Context); + bool isLanguageVersionSupported(const LangOptions &LangOpts) const override { return LangOpts.CPlusPlus; } + void registerMatchers(ast_matchers::MatchFinder *Finder) override; void check(const ast_matchers::MatchFinder::MatchResult &Result) override; + +private: + const std::vector<StringRef> StringLikeClasses; }; } // namespace clang::tidy::readability diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 1405fb0df1f8dd..cbafff01b58592 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -286,6 +286,11 @@ Changes in existing checks check by resolving fix-it overlaps in template code by disregarding implicit instances. +- Improved :doc:`readability-string-compare + <clang-tidy/checks/readability/string-compare>` check to also detect + usages of `std::string_view::compare`. Added a `StringLikeClasses` option + to detect usages of `compare` method in custom string-like classes. + Removed checks ^^^^^^^^^^^^^^ diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability/string-compare.rst b/clang-tools-extra/docs/clang-tidy/checks/readability/string-compare.rst index 268632eee61a27..f86ea6704ad56e 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/readability/string-compare.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/readability/string-compare.rst @@ -14,10 +14,12 @@ recommended to avoid the risk of incorrect interpretation of the return value and to simplify the code. The string equality and inequality operators can also be faster than the ``compare`` method due to early termination. -Examples: +Example +------- .. code-block:: c++ + // The same rules apply to std::string_view. std::string str1{"a"}; std::string str2{"b"}; @@ -50,5 +52,32 @@ Examples: } The above code examples show the list of if-statements that this check will -give a warning for. All of them uses ``compare`` to check if equality or +give a warning for. All of them use ``compare`` to check equality or inequality of two strings instead of using the correct operators. + +Options +------- + +.. option:: StringLikeClasses + + A string containing comma-separated names of string-like classes. Default is an empty string. + If a class from this list has a ``compare`` method similar to ``std::string``, it will be checked in the same way. + +Example +^^^^^^^ + +.. code-block:: c++ + + struct CustomString { + public: + int compare (const CustomString& other) const; + } + + CustomString str1; + CustomString str2; + + // use str1 != str2 instead. + if (str1.compare(str2)) { + } + +If `StringLikeClasses` contains ``CustomString``, the check will suggest replacing ``compare`` with equality operator. diff --git a/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string index 28e2b4a231e52e..bc58fdad3fd44e 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string +++ b/clang-tools-extra/test/clang-tidy/checkers/Inputs/Headers/string @@ -106,6 +106,8 @@ struct basic_string_view { constexpr bool starts_with(C ch) const noexcept; constexpr bool starts_with(const C* s) const; + constexpr int compare(basic_string_view sv) const noexcept; + static constexpr size_t npos = -1; }; @@ -129,6 +131,14 @@ bool operator!=(const char*, const std::string&); bool operator==(const std::wstring&, const std::wstring&); bool operator==(const std::wstring&, const wchar_t*); bool operator==(const wchar_t*, const std::wstring&); + +bool operator==(const std::string_view&, const std::string_view&); +bool operator==(const std::string_view&, const char*); +bool operator==(const char*, const std::string_view&); + +bool operator!=(const std::string_view&, const std::string_view&); +bool operator!=(const std::string_view&, const char*); +bool operator!=(const char*, const std::string_view&); } #endif // _STRING_ diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare-custom-string-classes.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare-custom-string-classes.cpp new file mode 100644 index 00000000000000..2bb47d33da389d --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare-custom-string-classes.cpp @@ -0,0 +1,38 @@ +// RUN: %check_clang_tidy %s readability-string-compare %t -- -config='{CheckOptions: {readability-string-compare.StringLikeClasses: "CustomStringTemplateBase;CustomStringNonTemplateBase"}}' -- -isystem %clang_tidy_headers +#include <string> + +struct CustomStringNonTemplateBase { + int compare(const CustomStringNonTemplateBase& Other) const { + return 123; // value is not important for check + } +}; + +template <typename T> +struct CustomStringTemplateBase { + int compare(const CustomStringTemplateBase& Other) const { + return 123; + } +}; + +struct CustomString1 : CustomStringNonTemplateBase {}; +struct CustomString2 : CustomStringTemplateBase<char> {}; + +void StdClassesAreStillDetected() { + std::string_view sv1("a"); + std::string_view sv2("b"); + if (sv1.compare(sv2)) { + } + // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; use the string equality operator instead [readability-string-compare] +} + +void CustomStringClasses() { + CustomString1 custom1; + if (custom1.compare(custom1)) { + } + // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; use the string equality operator instead [readability-string-compare] + + CustomString2 custom2; + if (custom2.compare(custom2)) { + } + // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; use the string equality operator instead [readability-string-compare] +} diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare.cpp index 2c08b86cf72fa0..c4fea4341617b8 100644 --- a/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare.cpp +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/string-compare.cpp @@ -67,11 +67,27 @@ void Test() { if (str1.compare(comp())) { } // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; + + std::string_view sv1("a"); + std::string_view sv2("b"); + if (sv1.compare(sv2)) { + } + // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; use the string equality operator instead [readability-string-compare] +} + +struct DerivedFromStdString : std::string {}; + +void TestDerivedClass() { + DerivedFromStdString derived; + if (derived.compare(derived)) { + } + // CHECK-MESSAGES: [[@LINE-2]]:7: warning: do not use 'compare' to test equality of strings; use the string equality operator instead [readability-string-compare] } void Valid() { std::string str1("a", 1); std::string str2("b", 1); + if (str1 == str2) { } if (str1 != str2) { @@ -96,4 +112,11 @@ void Valid() { } if (str1.compare(str2) == -1) { } + + std::string_view sv1("a"); + std::string_view sv2("b"); + if (sv1 == sv2) { + } + if (sv1.compare(sv2) > 0) { + } } `````````` </details> https://github.com/llvm/llvm-project/pull/88636 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
