Author: Congcong Cai Date: 2024-01-15T18:19:47+08:00 New Revision: 8e21557d0401a0046ff110daa50f21d02b71a2ee
URL: https://github.com/llvm/llvm-project/commit/8e21557d0401a0046ff110daa50f21d02b71a2ee DIFF: https://github.com/llvm/llvm-project/commit/8e21557d0401a0046ff110daa50f21d02b71a2ee.diff LOG: [clang-tidy]Add new check readability-avoid-nested-conditional-operator (#78022) Finds nested conditional operator. Nested conditional operators lead code hard to understand, so they should be splited as several statement and stored in temporary varibale. Added: clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp Modified: clang-tools-extra/clang-tidy/readability/CMakeLists.txt clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp clang-tools-extra/docs/ReleaseNotes.rst clang-tools-extra/docs/clang-tidy/checks/list.rst Removed: ################################################################################ diff --git a/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp new file mode 100644 index 00000000000000..2ea03c9070526f --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.cpp @@ -0,0 +1,52 @@ +//===--- AvoidNestedConditionalOperatorCheck.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 "AvoidNestedConditionalOperatorCheck.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/ASTMatchers/ASTMatchers.h" +#include "clang/Basic/DiagnosticIDs.h" + +using namespace clang::ast_matchers; + +namespace clang::tidy::readability { + +void AvoidNestedConditionalOperatorCheck::registerMatchers( + MatchFinder *Finder) { + Finder->addMatcher( + conditionalOperator( + anyOf( + hasCondition(ignoringParenCasts( + conditionalOperator().bind("nested-conditional-operator"))), + hasTrueExpression(ignoringParenCasts( + conditionalOperator().bind("nested-conditional-operator"))), + hasFalseExpression(ignoringParenCasts( + conditionalOperator().bind("nested-conditional-operator"))))) + .bind("conditional-operator"), + this); +} + +void AvoidNestedConditionalOperatorCheck::check( + const MatchFinder::MatchResult &Result) { + const auto *CO = + Result.Nodes.getNodeAs<ConditionalOperator>("conditional-operator"); + const auto *NCO = Result.Nodes.getNodeAs<ConditionalOperator>( + "nested-conditional-operator"); + assert(CO); + assert(NCO); + + if (CO->getBeginLoc().isMacroID() || NCO->getBeginLoc().isMacroID()) + return; + + diag(NCO->getBeginLoc(), + "conditional operator is used as sub-expression of parent conditional " + "operator, refrain from using nested conditional operators"); + diag(CO->getBeginLoc(), "parent conditional operator here", + DiagnosticIDs::Note); +} + +} // namespace clang::tidy::readability diff --git a/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h new file mode 100644 index 00000000000000..9010156de6ce2d --- /dev/null +++ b/clang-tools-extra/clang-tidy/readability/AvoidNestedConditionalOperatorCheck.h @@ -0,0 +1,33 @@ +//===--- AvoidNestedConditionalOperatorCheck.h - clang-tidy -----*- C++ -*-===// +// +// 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_READABILITY_AVOID_NESTED_CONDITIONAL_OPERATOR_CHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOID_NESTED_CONDITIONAL_OPERATOR_CHECK_H + +#include "../ClangTidyCheck.h" + +namespace clang::tidy::readability { + +/// Identifies instances of nested conditional operators in the code. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/readability/avoid-nested-conditional-operator.html +class AvoidNestedConditionalOperatorCheck : public ClangTidyCheck { +public: + AvoidNestedConditionalOperatorCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; + std::optional<TraversalKind> getCheckTraversalKind() const override { + return TK_IgnoreUnlessSpelledInSource; + } +}; + +} // namespace clang::tidy::readability + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_AVOID_NESTED_CONDITIONAL_OPERATOR_CHECK_H diff --git a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt index 408c822b861c5f..fa571d5dd7650d 100644 --- a/clang-tools-extra/clang-tidy/readability/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/readability/CMakeLists.txt @@ -5,6 +5,7 @@ set(LLVM_LINK_COMPONENTS add_clang_library(clangTidyReadabilityModule AvoidConstParamsInDecls.cpp + AvoidNestedConditionalOperatorCheck.cpp AvoidReturnWithVoidValueCheck.cpp AvoidUnconditionalPreprocessorIfCheck.cpp BracesAroundStatementsCheck.cpp diff --git a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp index 0b0aad7c0dcb36..f769752c5de5fa 100644 --- a/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/readability/ReadabilityTidyModule.cpp @@ -10,6 +10,7 @@ #include "../ClangTidyModule.h" #include "../ClangTidyModuleRegistry.h" #include "AvoidConstParamsInDecls.h" +#include "AvoidNestedConditionalOperatorCheck.h" #include "AvoidReturnWithVoidValueCheck.h" #include "AvoidUnconditionalPreprocessorIfCheck.h" #include "BracesAroundStatementsCheck.h" @@ -64,6 +65,8 @@ class ReadabilityModule : public ClangTidyModule { void addCheckFactories(ClangTidyCheckFactories &CheckFactories) override { CheckFactories.registerCheck<AvoidConstParamsInDecls>( "readability-avoid-const-params-in-decls"); + CheckFactories.registerCheck<AvoidNestedConditionalOperatorCheck>( + "readability-avoid-nested-conditional-operator"); CheckFactories.registerCheck<AvoidReturnWithVoidValueCheck>( "readability-avoid-return-with-void-value"); CheckFactories.registerCheck<AvoidUnconditionalPreprocessorIfCheck>( diff --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst index 344a7ed5798835..a235a7d02592e8 100644 --- a/clang-tools-extra/docs/ReleaseNotes.rst +++ b/clang-tools-extra/docs/ReleaseNotes.rst @@ -224,6 +224,11 @@ New checks Recommends the smallest possible underlying type for an ``enum`` or ``enum`` class based on the range of its enumerators. +- New :doc:`readability-avoid-nested-conditional-operator + <clang-tidy/checks/readability/avoid-nested-conditional-operator>` check. + + Identifies instances of nested conditional operators in the code. + - New :doc:`readability-avoid-return-with-void-value <clang-tidy/checks/readability/avoid-return-with-void-value>` check. diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst index 2f86121ad87299..5f21449cfc3df4 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -337,6 +337,7 @@ Clang-Tidy Checks :doc:`portability-simd-intrinsics <portability/simd-intrinsics>`, :doc:`portability-std-allocator-const <portability/std-allocator-const>`, :doc:`readability-avoid-const-params-in-decls <readability/avoid-const-params-in-decls>`, "Yes" + :doc:`readability-avoid-nested-conditional-operator <readability/avoid-nested-conditional-operator>`, :doc:`readability-avoid-return-with-void-value <readability/avoid-return-with-void-value>`, :doc:`readability-avoid-unconditional-preprocessor-if <readability/avoid-unconditional-preprocessor-if>`, :doc:`readability-braces-around-statements <readability/braces-around-statements>`, "Yes" diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst b/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst new file mode 100644 index 00000000000000..44b74283292ce0 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/readability/avoid-nested-conditional-operator.rst @@ -0,0 +1,21 @@ +.. title:: clang-tidy - readability-avoid-nested-conditional-operator + +readability-avoid-nested-conditional-operator +============================================= + +Identifies instances of nested conditional operators in the code. + +Nested conditional operators, also known as ternary operators, can contribute +to reduced code readability and comprehension. So they should be split as +several statements and stored the intermediate results in temporary variable. + +Examples: + +.. code-block:: c++ + + int NestInConditional = (condition1 ? true1 : false1) ? true2 : false2; + int NestInTrue = condition1 ? (condition2 ? true1 : false1) : false2; + int NestInFalse = condition1 ? true1 : condition2 ? true2 : false1; + +This check implements part of `AUTOSAR C++14 Rule A5-16-1 +<https://www.autosar.org/fileadmin/standards/R22-11/AP/AUTOSAR_RS_CPP14Guidelines.pdf>`_. diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp new file mode 100644 index 00000000000000..847df08199e349 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability/avoid-nested-conditional-operator.cpp @@ -0,0 +1,24 @@ +// RUN: %check_clang_tidy %s readability-avoid-nested-conditional-operator %t + +int NestInConditional = (true ? true : false) ? 1 : 2; +// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators +// CHECK-MESSAGES: :[[@LINE-2]]:25: note: parent conditional operator here + +int NestInTrue = true ? (true ? 1 : 2) : 2; +// CHECK-MESSAGES: :[[@LINE-1]]:26: warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators +// CHECK-MESSAGES: :[[@LINE-2]]:18: note: parent conditional operator here + +int NestInFalse = true ? 1 : true ? 1 : 2; +// CHECK-MESSAGES: :[[@LINE-1]]:30: warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators +// CHECK-MESSAGES: :[[@LINE-2]]:19: note: parent conditional operator here +int NestInFalse2 = true ? 1 : (true ? 1 : 2); +// CHECK-MESSAGES: :[[@LINE-1]]:32: warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators +// CHECK-MESSAGES: :[[@LINE-2]]:20: note: parent conditional operator here + +int NestWithParensis = true ? 1 : ((((true ? 1 : 2)))); +// CHECK-MESSAGES: :[[@LINE-1]]:39: warning: conditional operator is used as sub-expression of parent conditional operator, refrain from using nested conditional operators +// CHECK-MESSAGES: :[[@LINE-2]]:24: note: parent conditional operator here + +#define CONDITIONAL_EXPR (true ? 1 : 2) +// not diag for macro since it will not reduce readability +int NestWithMacro = true ? CONDITIONAL_EXPR : 2; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits