llvm/clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp

//===--- PassByValueCheck.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 "PassByValueCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/RecursiveASTVisitor.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchers.h"
#include "clang/Frontend/CompilerInstance.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/Preprocessor.h"

usingnamespaceclang::ast_matchers;
usingnamespacellvm;

namespace clang::tidy::modernize {

namespace {
/// Matches move-constructible classes.
///
/// Given
/// \code
///   // POD types are trivially move constructible.
///   struct Foo { int a; };
///
///   struct Bar {
///     Bar(Bar &&) = deleted;
///     int a;
///   };
/// \endcode
/// recordDecl(isMoveConstructible())
///   matches "Foo".
AST_MATCHER(CXXRecordDecl, isMoveConstructible) { … }
} // namespace

static TypeMatcher notTemplateSpecConstRefType() { … }

static TypeMatcher nonConstValueType() { … }

/// Whether or not \p ParamDecl is used exactly one time in \p Ctor.
///
/// Checks both in the init-list and the body of the constructor.
static bool paramReferredExactlyOnce(const CXXConstructorDecl *Ctor,
                                     const ParmVarDecl *ParamDecl) { … }

/// Returns true if the given constructor is part of a lvalue/rvalue reference
/// pair, i.e. `Param` is of lvalue reference type, and there exists another
/// constructor such that:
///  - it has the same number of parameters as `Ctor`.
///  - the parameter at the same index as `Param` is an rvalue reference
///    of the same pointee type
///  - all other parameters have the same type as the corresponding parameter in
///    `Ctor` or are rvalue references with the same pointee type.
/// Examples:
///  A::A(const B& Param)
///  A::A(B&&)
///
///  A::A(const B& Param, const C&)
///  A::A(B&& Param, C&&)
///
///  A::A(const B&, const C& Param)
///  A::A(B&&, C&& Param)
///
///  A::A(const B&, const C& Param)
///  A::A(const B&, C&& Param)
///
///  A::A(const B& Param, int)
///  A::A(B&& Param, int)
static bool hasRValueOverload(const CXXConstructorDecl *Ctor,
                              const ParmVarDecl *Param) { … }

/// Find all references to \p ParamDecl across all of the
/// redeclarations of \p Ctor.
static SmallVector<const ParmVarDecl *, 2>
collectParamDecls(const CXXConstructorDecl *Ctor,
                  const ParmVarDecl *ParamDecl) { … }

PassByValueCheck::PassByValueCheck(StringRef Name, ClangTidyContext *Context)
    : … { … }

void PassByValueCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) { … }

void PassByValueCheck::registerMatchers(MatchFinder *Finder) { … }

void PassByValueCheck::registerPPCallbacks(const SourceManager &SM,
                                           Preprocessor *PP,
                                           Preprocessor *ModuleExpanderPP) { … }

void PassByValueCheck::check(const MatchFinder::MatchResult &Result) { … }

} // namespace clang::tidy::modernize