A check that flags value parameters of expensive to copy types that can safely be converted to const references. More...

#include <UnnecessaryValueParamCheck.h>

Inheritance diagram for clang::tidy::performance::UnnecessaryValueParamCheck:

[legend]

Public Member Functions
	UnnecessaryValueParamCheck (StringRef Name, ClangTidyContext *Context)

bool	isLanguageVersionSupported (const LangOptions &LangOpts) const override
	Override this to disable registering matchers and PP callbacks if an invalid language version is being used.

void	registerMatchers (ast_matchers::MatchFinder *Finder) override
	Override this to register AST matchers with `Finder`.

void	check (const ast_matchers::MatchFinder::MatchResult &Result) override
	`ClangTidyChecks` that register ASTMatchers should do the actual work in here.

void	registerPPCallbacks (const SourceManager &SM, Preprocessor PP, Preprocessor ModuleExpanderPP) override
	Override this to register `PPCallbacks` in the preprocessor.

void	storeOptions (ClangTidyOptions::OptionMap &Opts) override
	Should store all options supported by this check with their current values or default values for options that haven't been overridden.

void	onEndOfTranslationUnit () override

Public Member Functions inherited from clang::tidy::ClangTidyCheck
	ClangTidyCheck (StringRef CheckName, ClangTidyContext *Context)
	Initializes the check with `CheckName` and `Context`.

virtual bool	isLanguageVersionSupported (const LangOptions &LangOpts) const
	Override this to disable registering matchers and PP callbacks if an invalid language version is being used.

virtual void	registerPPCallbacks (const SourceManager &SM, Preprocessor PP, Preprocessor ModuleExpanderPP)
	Override this to register `PPCallbacks` in the preprocessor.

virtual void	registerMatchers (ast_matchers::MatchFinder *Finder)
	Override this to register AST matchers with `Finder`.

virtual void	check (const ast_matchers::MatchFinder::MatchResult &Result)
	`ClangTidyChecks` that register ASTMatchers should do the actual work in here.

DiagnosticBuilder	diag (SourceLocation Loc, StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
	Add a diagnostic with the check's name.

DiagnosticBuilder	diag (StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning)
	Add a diagnostic with the check's name.

DiagnosticBuilder	configurationDiag (StringRef Description, DiagnosticIDs::Level Level=DiagnosticIDs::Warning) const
	Adds a diagnostic to report errors in the check's configuration.

virtual void	storeOptions (ClangTidyOptions::OptionMap &Options)
	Should store all options supported by this check with their current values or default values for options that haven't been overridden.

Protected Member Functions
virtual void	handleMoveFix (const ParmVarDecl &Param, const DeclRefExpr &CopyArgument, ASTContext &Context)

virtual void	handleConstRefFix (const FunctionDecl &Function, const ParmVarDecl &Param, ASTContext &Context)

Protected Member Functions inherited from clang::tidy::ClangTidyCheck
StringRef	getCurrentMainFile () const
	Returns the main file name of the current translation unit.

const LangOptions &	getLangOpts () const
	Returns the language options from the context.

bool	areDiagsSelfContained () const
	Returns true when the check is run in a use case when only 1 fix will be applied at a time.

StringRef	getID () const override

Additional Inherited Members
Protected Attributes inherited from clang::tidy::ClangTidyCheck
OptionsView	Options

Detailed Description

A check that flags value parameters of expensive to copy types that can safely be converted to const references.

For the user-facing documentation see: http://clang.llvm.org/extra/clang-tidy/checks/performance/unnecessary-value-param.html

Definition at line 23 of file UnnecessaryValueParamCheck.h.

Constructor & Destructor Documentation

◆ UnnecessaryValueParamCheck()

clang::tidy::performance::UnnecessaryValueParamCheck::UnnecessaryValueParamCheck	(	StringRef	Name,
		ClangTidyContext *	Context
	)

Definition at line 55 of file UnnecessaryValueParamCheck.cpp.

Member Function Documentation

◆ check()

void clang::tidy::performance::UnnecessaryValueParamCheck::check ( const ast_matchers::MatchFinder::MatchResult & Result )

overridevirtual

ClangTidyChecks that register ASTMatchers should do the actual work in here.

Reimplemented from clang::tidy::ClangTidyCheck.

Definition at line 82 of file UnnecessaryValueParamCheck.cpp.

References clang::tidy::utils::decl_ref_expr::allDeclRefExprs(), handleConstRefFix(), handleMoveFix(), clang::tidy::utils::type_traits::hasNonTrivialMoveAssignment(), clang::tidy::utils::type_traits::hasNonTrivialMoveConstructor(), clang::tidy::utils::decl_ref_expr::isCopyAssignmentArgument(), and clang::tidy::utils::decl_ref_expr::isCopyConstructorArgument().

◆ handleConstRefFix()

void clang::tidy::performance::UnnecessaryValueParamCheck::handleConstRefFix	(	const FunctionDecl &	Function,
		const ParmVarDecl &	Param,
		ASTContext &	Context
	)

protectedvirtual

Definition at line 141 of file UnnecessaryValueParamCheck.cpp.

References clang::tidy::utils::fixit::addQualifierToVarDecl(), clang::tidy::utils::fixit::changeVarDeclToReference(), clang::tidy::ClangTidyCheck::diag(), and Fix().

Referenced by check().

◆ handleMoveFix()

void clang::tidy::performance::UnnecessaryValueParamCheck::handleMoveFix	(	const ParmVarDecl &	Param,
		const DeclRefExpr &	CopyArgument,
		ASTContext &	Context
	)

protectedvirtual

Definition at line 181 of file UnnecessaryValueParamCheck.cpp.

References clang::tidy::utils::IncludeInserter::createIncludeInsertion(), and clang::tidy::ClangTidyCheck::diag().

Referenced by check().

◆ isLanguageVersionSupported()

bool clang::tidy::performance::UnnecessaryValueParamCheck::isLanguageVersionSupported ( const LangOptions & LangOpts ) const

inlineoverridevirtual

Override this to disable registering matchers and PP callbacks if an invalid language version is being used.

For example if a check is examining overloaded functions then this should be overridden to return false when the CPlusPlus flag is not set in LangOpts.

Reimplemented from clang::tidy::ClangTidyCheck.

Definition at line 26 of file UnnecessaryValueParamCheck.h.

◆ onEndOfTranslationUnit()

void clang::tidy::performance::UnnecessaryValueParamCheck::onEndOfTranslationUnit ( )

override

Definition at line 137 of file UnnecessaryValueParamCheck.cpp.

◆ registerMatchers()

void clang::tidy::performance::UnnecessaryValueParamCheck::registerMatchers ( ast_matchers::MatchFinder * Finder )

overridevirtual

Override this to register AST matchers with Finder.

This should be used by clang-tidy checks that analyze code properties that dependent on AST knowledge.

You can register as many matchers as necessary with Finder. Usually, "this" will be used as callback, but you can also specify other callback classes. Thereby, different matchers can trigger different callbacks.

This will only be executed if the function isLanguageVersionSupported returns true.

If you need to merge information between the different matchers, you can store these as members of the derived class. However, note that all matches occur in the order of the AST traversal.

Reimplemented from clang::tidy::ClangTidyCheck.

Definition at line 64 of file UnnecessaryValueParamCheck.cpp.

References clang::tidy::matchers::matchesAnyListedName().

◆ registerPPCallbacks()

void clang::tidy::performance::UnnecessaryValueParamCheck::registerPPCallbacks	(	const SourceManager &	SM,
		Preprocessor *	PP,
		Preprocessor *	ModuleExpanderPP
	)

overridevirtual

Override this to register PPCallbacks in the preprocessor.

This should be used for clang-tidy checks that analyze preprocessor- dependent properties, e.g. include directives and macro definitions.

This will only be executed if the function isLanguageVersionSupported returns true.

There are two Preprocessors to choose from that differ in how they handle modular #includes:

PP is the real Preprocessor. It doesn't walk into modular #includes and thus doesn't generate PPCallbacks for their contents.
ModuleExpanderPP preprocesses the whole translation unit in the non-modular mode, which allows it to generate PPCallbacks not only for the main file and textual headers, but also for all transitively included modular headers when the analysis runs with modules enabled. When modules are not enabled ModuleExpanderPP just points to the real preprocessor.

Reimplemented from clang::tidy::ClangTidyCheck.

Definition at line 125 of file UnnecessaryValueParamCheck.cpp.

References clang::tidy::utils::IncludeInserter::registerPreprocessor().