85 lines
2.8 KiB
C++
85 lines
2.8 KiB
C++
//===--- ReferenceToConstructedTemporaryCheck.cpp - clang-tidy
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//--------------===//
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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 "ReferenceToConstructedTemporaryCheck.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::tidy::readability {
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namespace {
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// Predicate structure to check if lifetime of temporary is not extended by
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// ValueDecl pointed out by ID
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struct NotExtendedByDeclBoundToPredicate {
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bool operator()(const internal::BoundNodesMap &Nodes) const {
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const auto *Other = Nodes.getNodeAs<ValueDecl>(ID);
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if (!Other)
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return true;
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const auto *Self = Node.get<MaterializeTemporaryExpr>();
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if (!Self)
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return true;
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return Self->getExtendingDecl() != Other;
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}
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StringRef ID;
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::clang::DynTypedNode Node;
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};
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AST_MATCHER_P(MaterializeTemporaryExpr, isExtendedByDeclBoundTo, StringRef,
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ID) {
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NotExtendedByDeclBoundToPredicate Predicate{
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ID, ::clang::DynTypedNode::create(Node)};
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return Builder->removeBindings(Predicate);
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}
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} // namespace
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bool ReferenceToConstructedTemporaryCheck::isLanguageVersionSupported(
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const LangOptions &LangOpts) const {
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return LangOpts.CPlusPlus;
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}
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std::optional<TraversalKind>
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ReferenceToConstructedTemporaryCheck::getCheckTraversalKind() const {
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return TK_AsIs;
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}
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void ReferenceToConstructedTemporaryCheck::registerMatchers(
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MatchFinder *Finder) {
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Finder->addMatcher(
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varDecl(unless(isExpansionInSystemHeader()),
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hasType(qualType(references(qualType().bind("type")))),
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decl().bind("var"),
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hasInitializer(expr(hasDescendant(
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materializeTemporaryExpr(
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isExtendedByDeclBoundTo("var"),
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has(expr(anyOf(cxxTemporaryObjectExpr(), initListExpr(),
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cxxConstructExpr()),
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hasType(qualType(equalsBoundNode("type"))))))
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.bind("temporary"))))),
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this);
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}
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void ReferenceToConstructedTemporaryCheck::check(
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const MatchFinder::MatchResult &Result) {
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const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("var");
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const auto *MatchedTemporary = Result.Nodes.getNodeAs<Expr>("temporary");
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diag(MatchedDecl->getLocation(),
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"reference variable %0 extends the lifetime of a just-constructed "
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"temporary object %1, consider changing reference to value")
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<< MatchedDecl << MatchedTemporary->getType();
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}
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} // namespace clang::tidy::readability
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