86 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 "BoolPointerImplicitConversionCheck.h"10 11using namespace clang::ast_matchers;12 13namespace clang::tidy::bugprone {14 15void BoolPointerImplicitConversionCheck::registerMatchers(MatchFinder *Finder) {16 // Look for ifs that have an implicit bool* to bool conversion in the17 // condition. Filter negations.18 Finder->addMatcher(19 traverse(20 TK_AsIs,21 ifStmt(22 hasCondition(findAll(implicitCastExpr(23 unless(hasParent(unaryOperator(hasOperatorName("!")))),24 hasSourceExpression(expr(25 hasType(pointerType(pointee(booleanType()))),26 ignoringParenImpCasts(anyOf(declRefExpr().bind("expr"),27 memberExpr().bind("expr"))))),28 hasCastKind(CK_PointerToBoolean)))),29 unless(isInTemplateInstantiation()))30 .bind("if")),31 this);32}33 34static void checkImpl(const MatchFinder::MatchResult &Result, const Expr *Ref,35 const IfStmt *If,36 const ast_matchers::internal::Matcher<Expr> &RefMatcher,37 ClangTidyCheck &Check) {38 // Ignore macros.39 if (Ref->getBeginLoc().isMacroID())40 return;41 42 // Only allow variable accesses and member exprs for now, no function calls.43 // Check that we don't dereference the variable anywhere within the if. This44 // avoids false positives for checks of the pointer for nullptr before it is45 // dereferenced. If there is a dereferencing operator on this variable don't46 // emit a diagnostic. Also ignore array subscripts.47 if (!match(findAll(unaryOperator(hasOperatorName("*"),48 hasUnaryOperand(RefMatcher))),49 *If, *Result.Context)50 .empty() ||51 !match(findAll(arraySubscriptExpr(hasBase(RefMatcher))), *If,52 *Result.Context)53 .empty() ||54 // FIXME: We should still warn if the paremater is implicitly converted to55 // bool.56 !match(57 findAll(callExpr(hasAnyArgument(ignoringParenImpCasts(RefMatcher)))),58 *If, *Result.Context)59 .empty() ||60 !match(61 findAll(cxxDeleteExpr(has(ignoringParenImpCasts(expr(RefMatcher))))),62 *If, *Result.Context)63 .empty())64 return;65 66 Check.diag(Ref->getBeginLoc(),67 "dubious check of 'bool *' against 'nullptr', did "68 "you mean to dereference it?")69 << FixItHint::CreateInsertion(Ref->getBeginLoc(), "*");70}71 72void BoolPointerImplicitConversionCheck::check(73 const MatchFinder::MatchResult &Result) {74 const auto *If = Result.Nodes.getNodeAs<IfStmt>("if");75 if (const auto *E = Result.Nodes.getNodeAs<Expr>("expr")) {76 const Decl *D = isa<DeclRefExpr>(E) ? cast<DeclRefExpr>(E)->getDecl()77 : cast<MemberExpr>(E)->getMemberDecl();78 const auto M =79 ignoringParenImpCasts(anyOf(declRefExpr(to(equalsNode(D))),80 memberExpr(hasDeclaration(equalsNode(D)))));81 checkImpl(Result, E, If, M, *this);82 }83}84 85} // namespace clang::tidy::bugprone86