98 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "UnusedRaiiCheck.h"10#include "clang/AST/ASTContext.h"11#include "clang/Lex/Lexer.h"12 13using namespace clang::ast_matchers;14 15namespace clang::tidy::bugprone {16 17namespace {18AST_MATCHER(CXXRecordDecl, hasNonTrivialDestructor) {19 // TODO: If the dtor is there but empty we don't want to warn either.20 return Node.hasDefinition() && Node.hasNonTrivialDestructor();21}22} // namespace23 24void UnusedRaiiCheck::registerMatchers(MatchFinder *Finder) {25 // Look for temporaries that are constructed in-place and immediately26 // destroyed.27 Finder->addMatcher(28 mapAnyOf(cxxConstructExpr, cxxUnresolvedConstructExpr)29 .with(hasParent(compoundStmt().bind("compound")),30 anyOf(hasType(hasCanonicalType(recordType(hasDeclaration(31 cxxRecordDecl(hasNonTrivialDestructor()))))),32 hasType(hasCanonicalType(templateSpecializationType(33 hasDeclaration(classTemplateDecl(has(34 cxxRecordDecl(hasNonTrivialDestructor())))))))))35 .bind("expr"),36 this);37}38 39template <typename T>40static void reportDiagnostic(const DiagnosticBuilder &D, const T *Node,41 SourceRange SR, bool DefaultConstruction) {42 const char *Replacement = " give_me_a_name";43 44 // If this is a default ctor we have to remove the parens or we'll introduce a45 // most vexing parse.46 if (DefaultConstruction) {47 D << FixItHint::CreateReplacement(CharSourceRange::getTokenRange(SR),48 Replacement);49 return;50 }51 52 // Otherwise just suggest adding a name. To find the place to insert the name53 // find the first TypeLoc in the children of E, which always points to the54 // written type.55 D << FixItHint::CreateInsertion(SR.getBegin(), Replacement);56}57 58void UnusedRaiiCheck::check(const MatchFinder::MatchResult &Result) {59 const auto *E = Result.Nodes.getNodeAs<Expr>("expr");60 61 // We ignore code expanded from macros to reduce the number of false62 // positives.63 if (E->getBeginLoc().isMacroID())64 return;65 66 // Don't emit a warning for the last statement in the surrounding compound67 // statement.68 const auto *CS = Result.Nodes.getNodeAs<CompoundStmt>("compound");69 const auto *LastExpr = dyn_cast<Expr>(CS->body_back());70 71 if (LastExpr && E == LastExpr->IgnoreUnlessSpelledInSource())72 return;73 74 // Emit a warning.75 auto D = diag(E->getBeginLoc(), "object destroyed immediately after "76 "creation; did you mean to name the object?");77 78 if (const auto *Node = dyn_cast<CXXConstructExpr>(E))79 reportDiagnostic(D, Node, Node->getParenOrBraceRange(),80 Node->getNumArgs() == 0 ||81 isa<CXXDefaultArgExpr>(Node->getArg(0)));82 if (const auto *Node = dyn_cast<CXXUnresolvedConstructExpr>(E)) {83 auto SR = SourceRange(Node->getLParenLoc(), Node->getRParenLoc());84 auto DefaultConstruction = Node->getNumArgs() == 0;85 if (!DefaultConstruction) {86 auto *FirstArg = Node->getArg(0);87 DefaultConstruction = isa<CXXDefaultArgExpr>(FirstArg);88 if (auto *ILE = dyn_cast<InitListExpr>(FirstArg)) {89 DefaultConstruction = ILE->getNumInits() == 0;90 SR = SourceRange(ILE->getLBraceLoc(), ILE->getRBraceLoc());91 }92 }93 reportDiagnostic(D, Node, SR, DefaultConstruction);94 }95}96 97} // namespace clang::tidy::bugprone98