90 lines
3.2 KiB
C++
90 lines
3.2 KiB
C++
//===--- MoveConstructorInitCheck.cpp - clang-tidy-------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "MoveConstructorInitCheck.h"
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#include "../utils/Matchers.h"
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#include "clang/AST/ASTContext.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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using namespace clang::ast_matchers;
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namespace clang {
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namespace tidy {
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namespace performance {
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MoveConstructorInitCheck::MoveConstructorInitCheck(StringRef Name,
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ClangTidyContext *Context)
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: ClangTidyCheck(Name, Context) {}
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void MoveConstructorInitCheck::registerMatchers(MatchFinder *Finder) {
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Finder->addMatcher(
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traverse(TK_AsIs,
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cxxConstructorDecl(
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unless(isImplicit()), isMoveConstructor(),
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hasAnyConstructorInitializer(
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cxxCtorInitializer(
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withInitializer(cxxConstructExpr(hasDeclaration(
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cxxConstructorDecl(isCopyConstructor())
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.bind("ctor")))))
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.bind("move-init")))),
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this);
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}
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void MoveConstructorInitCheck::check(const MatchFinder::MatchResult &Result) {
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const auto *CopyCtor = Result.Nodes.getNodeAs<CXXConstructorDecl>("ctor");
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const auto *Initializer =
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Result.Nodes.getNodeAs<CXXCtorInitializer>("move-init");
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// Do not diagnose if the expression used to perform the initialization is a
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// trivially-copyable type.
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QualType QT = Initializer->getInit()->getType();
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if (QT.isTriviallyCopyableType(*Result.Context))
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return;
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if (QT.isConstQualified())
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return;
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const auto *RD = QT->getAsCXXRecordDecl();
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if (RD && RD->isTriviallyCopyable())
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return;
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// Diagnose when the class type has a move constructor available, but the
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// ctor-initializer uses the copy constructor instead.
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const CXXConstructorDecl *Candidate = nullptr;
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for (const auto *Ctor : CopyCtor->getParent()->ctors()) {
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if (Ctor->isMoveConstructor() && Ctor->getAccess() <= AS_protected &&
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!Ctor->isDeleted()) {
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// The type has a move constructor that is at least accessible to the
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// initializer.
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//
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// FIXME: Determine whether the move constructor is a viable candidate
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// for the ctor-initializer, perhaps provide a fix-it that suggests
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// using std::move().
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Candidate = Ctor;
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break;
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}
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}
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if (Candidate) {
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// There's a move constructor candidate that the caller probably intended
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// to call instead.
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diag(Initializer->getSourceLocation(),
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"move constructor initializes %select{class member|base class}0 by "
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"calling a copy constructor")
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<< Initializer->isBaseInitializer();
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diag(CopyCtor->getLocation(), "copy constructor being called",
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DiagnosticIDs::Note);
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diag(Candidate->getLocation(), "candidate move constructor here",
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DiagnosticIDs::Note);
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}
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}
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} // namespace performance
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} // namespace tidy
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} // namespace clang
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