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//===--- DeleteNullPointerCheck.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 "DeleteNullPointerCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Lex/Lexer.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace readability {
void DeleteNullPointerCheck::registerMatchers(MatchFinder *Finder) {
const auto DeleteExpr =
cxxDeleteExpr(has(castExpr(has(declRefExpr(
to(decl(equalsBoundNode("deletedPointer"))))))))
.bind("deleteExpr");
const auto DeleteMemberExpr =
cxxDeleteExpr(has(castExpr(has(memberExpr(hasDeclaration(
fieldDecl(equalsBoundNode("deletedMemberPointer"))))))))
.bind("deleteMemberExpr");
const auto PointerExpr = ignoringImpCasts(anyOf(
declRefExpr(to(decl().bind("deletedPointer"))),
memberExpr(hasDeclaration(fieldDecl().bind("deletedMemberPointer")))));
const auto PointerCondition = castExpr(hasCastKind(CK_PointerToBoolean),
hasSourceExpression(PointerExpr));
const auto BinaryPointerCheckCondition =
binaryOperator(hasEitherOperand(castExpr(hasCastKind(CK_NullToPointer))),
hasEitherOperand(PointerExpr));
Finder->addMatcher(
ifStmt(hasCondition(anyOf(PointerCondition, BinaryPointerCheckCondition)),
hasThen(anyOf(
DeleteExpr, DeleteMemberExpr,
compoundStmt(anyOf(has(DeleteExpr), has(DeleteMemberExpr)),
statementCountIs(1))
.bind("compound"))))
.bind("ifWithDelete"),
this);
}
void DeleteNullPointerCheck::check(const MatchFinder::MatchResult &Result) {
const auto *IfWithDelete = Result.Nodes.getNodeAs<IfStmt>("ifWithDelete");
const auto *Compound = Result.Nodes.getNodeAs<CompoundStmt>("compound");
auto Diag = diag(
IfWithDelete->getBeginLoc(),
"'if' statement is unnecessary; deleting null pointer has no effect");
if (IfWithDelete->getElse())
return;
// FIXME: generate fixit for this case.
Diag << FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
IfWithDelete->getBeginLoc(),
Lexer::getLocForEndOfToken(IfWithDelete->getCond()->getEndLoc(), 0,
*Result.SourceManager,
Result.Context->getLangOpts())));
if (Compound) {
Diag << FixItHint::CreateRemoval(
CharSourceRange::getTokenRange(Compound->getLBracLoc()));
Diag << FixItHint::CreateRemoval(
CharSourceRange::getTokenRange(Compound->getRBracLoc()));
}
}
} // namespace readability
} // namespace tidy
} // namespace clang
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