diff --git a/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.h b/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.h --- a/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.h +++ b/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.h @@ -17,10 +17,17 @@ /// Checks function Cognitive Complexity metric. /// -/// There is only one configuration option: +/// There are the following configuration option: /// /// * `Threshold` - flag functions with Cognitive Complexity exceeding /// this number. The default is `25`. +/// * `DescribeBasicIncrements`- if set to `true`, then for each function +/// exceeding the complexity threshold the check will issue additional +/// diagnostics on every piece of code (loop, `if` statement, etc.) which +/// contributes to that complexity. +// Default is `true` +/// * `IgnoreMacros` - if set to `true`, the check will ignore code inside +/// macros. Default is `false`. /// /// For the user-facing documentation see: /// http://clang.llvm.org/extra/clang-tidy/checks/readability-function-cognitive-complexity.html @@ -34,6 +41,8 @@ private: const unsigned Threshold; + const bool DescribeBasicIncrements; + const bool IgnoreMacros; }; } // namespace readability diff --git a/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.cpp b/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.cpp --- a/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.cpp +++ b/clang-tools-extra/clang-tidy/readability/FunctionCognitiveComplexityCheck.cpp @@ -213,6 +213,9 @@ : public RecursiveASTVisitor { using Base = RecursiveASTVisitor; + // If set to true, macros are ignored during analysis. + const bool IgnoreMacros; + // The current nesting level (increased by Criteria::IncrementNesting). unsigned short CurrentNestingLevel = 0; @@ -223,6 +226,9 @@ std::stack> BinaryOperatorsStack; public: + explicit FunctionASTVisitor(const bool IgnoreMacros) + : IgnoreMacros(IgnoreMacros){}; + bool traverseStmtWithIncreasedNestingLevel(Stmt *Node) { ++CurrentNestingLevel; bool ShouldContinue = Base::TraverseStmt(Node); @@ -364,6 +370,9 @@ if (!Node) return Base::TraverseStmt(Node); + if (IgnoreMacros && Node->getBeginLoc().isMacroID()) + return true; + // Three following switch()'es have huge duplication, but it is better to // keep them separate, to simplify comparing them with the Specification. @@ -492,11 +501,15 @@ FunctionCognitiveComplexityCheck::FunctionCognitiveComplexityCheck( StringRef Name, ClangTidyContext *Context) : ClangTidyCheck(Name, Context), - Threshold(Options.get("Threshold", CognitiveComplexity::DefaultLimit)) {} + Threshold(Options.get("Threshold", CognitiveComplexity::DefaultLimit)), + DescribeBasicIncrements(Options.get("DescribeBasicIncrements", true)), + IgnoreMacros(Options.get("IgnoreMacros", false)) {} void FunctionCognitiveComplexityCheck::storeOptions( ClangTidyOptions::OptionMap &Opts) { Options.store(Opts, "Threshold", Threshold); + Options.store(Opts, "DescribeBasicIncrements", DescribeBasicIncrements); + Options.store(Opts, "IgnoreMacros", IgnoreMacros); } void FunctionCognitiveComplexityCheck::registerMatchers(MatchFinder *Finder) { @@ -514,7 +527,7 @@ assert(Func->hasBody() && "The matchers should only match the functions that " "have user-provided body."); - FunctionASTVisitor Visitor; + FunctionASTVisitor Visitor(IgnoreMacros); Visitor.TraverseDecl(const_cast(Func), true); if (Visitor.CC.Total <= Threshold) @@ -524,6 +537,9 @@ "function %0 has cognitive complexity of %1 (threshold %2)") << Func << Visitor.CC.Total << Threshold; + if (!DescribeBasicIncrements) + return; + // Output all the basic increments of complexity. for (const auto &Detail : Visitor.CC.Details) { unsigned MsgId; // The id of the message to output. diff --git a/clang-tools-extra/docs/clang-tidy/checks/readability-function-cognitive-complexity.rst b/clang-tools-extra/docs/clang-tidy/checks/readability-function-cognitive-complexity.rst --- a/clang-tools-extra/docs/clang-tidy/checks/readability-function-cognitive-complexity.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/readability-function-cognitive-complexity.rst @@ -17,6 +17,19 @@ Flag functions with Cognitive Complexity exceeding this number. The default is `25`. +.. option:: DescribeBasicIncrements + + If set to `true`, then for each function exceeding the complexity threshold + the check will issue additional diagnostics on every piece of code (loop, + `if` statement, etc.) which contributes to that complexity. See also the + examples below. Default is `true`. + +.. option:: IgnoreMacros + + If set to `true`, the check will ignore code inside macros. Note, that also + any macro arguments are ignored, even if they should count to the complexity. + Default is `false`. + Building blocks --------------- @@ -135,6 +148,11 @@ return 0; } +In the last example, the check will flag `function3` if the option Threshold is +set to `2` or smaller. If the option DescribeBasicIncrements is set to `true`, +it will additionally flag the two `if` statements with the amounts by which they +increase to the complexity of the function and the current nesting level. + Limitations ----------- diff --git a/clang-tools-extra/test/clang-tidy/checkers/readability-function-cognitive-complexity-flags.cpp b/clang-tools-extra/test/clang-tidy/checkers/readability-function-cognitive-complexity-flags.cpp new file mode 100644 --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/checkers/readability-function-cognitive-complexity-flags.cpp @@ -0,0 +1,94 @@ +// RUN: %check_clang_tidy %s readability-function-cognitive-complexity %t -- \ +// RUN: -config='{CheckOptions: \ +// RUN: [{key: readability-function-cognitive-complexity.Threshold, \ +// RUN: value: 0}, \ +// RUN: {key: readability-function-cognitive-complexity.DescribeBasicIncrements, \ +// RUN: value: "false"} ]}' +// RUN: %check_clang_tidy -check-suffix=THRESHOLD5 %s readability-function-cognitive-complexity %t -- \ +// RUN: -config='{CheckOptions: \ +// RUN: [{key: readability-function-cognitive-complexity.Threshold, \ +// RUN: value: 5}, \ +// RUN: {key: readability-function-cognitive-complexity.DescribeBasicIncrements, \ +// RUN: value: "false"} ]}' +// RUN: %check_clang_tidy -check-suffix=IGNORE-MACROS %s readability-function-cognitive-complexity %t -- \ +// RUN: -config='{CheckOptions: \ +// RUN: [{key: readability-function-cognitive-complexity.Threshold, \ +// RUN: value: 0}, \ +// RUN: {key: readability-function-cognitive-complexity.IgnoreMacros, \ +// RUN: value: "true"}, \ +// RUN: {key: readability-function-cognitive-complexity.DescribeBasicIncrements, \ +// RUN: value: "false"} ]}' + +void func_of_complexity_4() { + // CHECK-NOTES: :[[@LINE-1]]:6: warning: function 'func_of_complexity_4' has cognitive complexity of 4 (threshold 0) [readability-function-cognitive-complexity] + // CHECK-NOTES-IGNORE-MACROS: :[[@LINE-2]]:6: warning: function 'func_of_complexity_4' has cognitive complexity of 4 (threshold 0) [readability-function-cognitive-complexity] + if (1) { + if (1) { + } + } + if (1) { + } +} + +#define MacroOfComplexity10 \ + if (1) { \ + if (1) { \ + if (1) { \ + if (1) { \ + } \ + } \ + } \ + } + +void function_with_macro() { + // CHECK-NOTES: :[[@LINE-1]]:6: warning: function 'function_with_macro' has cognitive complexity of 11 (threshold 0) [readability-function-cognitive-complexity] + // CHECK-NOTES-THRESHOLD5: :[[@LINE-2]]:6: warning: function 'function_with_macro' has cognitive complexity of 11 (threshold 5) [readability-function-cognitive-complexity] + // CHECK-NOTES-IGNORE-MACROS: :[[@LINE-3]]:6: warning: function 'function_with_macro' has cognitive complexity of 1 (threshold 0) [readability-function-cognitive-complexity] + + MacroOfComplexity10 + + if (1) { + } +} + +#define uglyfunctionmacro(name) \ + void name() { \ + if (true) { \ + try { \ + } catch (...) { \ + } \ + } \ + } + +uglyfunctionmacro(MacroFunction) +// CHECK-NOTES: :[[@LINE-1]]:19: warning: function 'MacroFunction' has cognitive complexity of 3 (threshold 0) [readability-function-cognitive-complexity] + +#define noop + +#define SomeMacro(x) \ + if (1) { \ + x \ + } + + void func_macro_1() { + // CHECK-NOTES: :[[@LINE-1]]:6: warning: function 'func_macro_1' has cognitive complexity of 2 (threshold 0) [readability-function-cognitive-complexity] + // CHECK-NOTES-IGNORE-MACROS: :[[@LINE-2]]:6: warning: function 'func_macro_1' has cognitive complexity of 1 (threshold 0) [readability-function-cognitive-complexity] + + if (1) { + } + SomeMacro(noop;) +} + +void func_macro_2() { + // CHECK-NOTES: :[[@LINE-1]]:6: warning: function 'func_macro_2' has cognitive complexity of 4 (threshold 0) [readability-function-cognitive-complexity] + // CHECK-NOTES-IGNORE-MACROS: :[[@LINE-2]]:6: warning: function 'func_macro_2' has cognitive complexity of 1 (threshold 0) [readability-function-cognitive-complexity] + + if (1) { + } + // Note that if the IgnoreMacro option is set to 'true', currently also macro + // arguments are ignored. Optimally, macros should be treated like function + // calls, i.e. the arguments account to the complexity so that the overall + // complexity of this function is 2 (1 for the if statement above + 1 for + // the if statement in the argument). + SomeMacro(if (1) { noop; }) +}