//==- ObjCPropertyChecker.cpp - Check ObjC properties ------------*- C++ -*-==//

//

// 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

//

//===----------------------------------------------------------------------===//

//

//  This checker finds issues with Objective-C properties.

//  Currently finds only one kind of issue:

//  - Find synthesized properties with copy attribute of mutable NS collection

//    types. Calling -copy on such collections produces an immutable copy,

//    which contradicts the type of the property.

//

//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"

#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"

#include "clang/StaticAnalyzer/Core/Checker.h"

using namespace clang;

using namespace ento;

namespace {

class ObjCPropertyChecker

    : public Checker<check::ASTDecl<ObjCPropertyDecl>> {

  void checkCopyMutable(const ObjCPropertyDecl *D, BugReporter &BR) const;

public:

  void checkASTDecl(const ObjCPropertyDecl *D, AnalysisManager &Mgr,

                    BugReporter &BR) const;

};

} // end anonymous namespace.

void ObjCPropertyChecker::checkASTDecl(const ObjCPropertyDecl *D,

                                       AnalysisManager &Mgr,

                                       BugReporter &BR) const {

  checkCopyMutable(D, BR);

}

void ObjCPropertyChecker::checkCopyMutable(const ObjCPropertyDecl *D,

                                           BugReporter &BR) const {

  if (D->isReadOnly() || 
D->getSetterKind() != ObjCPropertyDecl::Copy14
)

    return;

  QualType T = D->getType();

  if (!T->isObjCObjectPointerType())

    return;

  const std::string &PropTypeName(T->getPointeeType().getCanonicalType()

                                                     .getUnqualifiedType()

                                                     .getAsString());

  if (!StringRef(PropTypeName).startswith("NSMutable"))

    return;

  const ObjCImplDecl *ImplD = nullptr;

  if (const ObjCInterfaceDecl *IntD =

          dyn_cast<ObjCInterfaceDecl>(D->getDeclContext())) {

    ImplD = IntD->getImplementation();

  } else 
if (auto *3
CatD3
 = dyn_cast<ObjCCategoryDecl>(D->getDeclContext())) {

    ImplD = CatD->getClassInterface()->getImplementation();

  }

  if (!ImplD || 
ImplD->HasUserDeclaredSetterMethod(D)8
)

    return;

  SmallString<128> Str;

  llvm::raw_svector_ostream OS(Str);

  OS << "Property of mutable type '" << PropTypeName

     << "' has 'copy' attribute; an immutable object will be stored instead";

  BR.EmitBasicReport(

      D, this, "Objective-C property misuse", "Logic error", OS.str(),

      PathDiagnosticLocation::createBegin(D, BR.getSourceManager()),

      D->getSourceRange());

}

void ento::registerObjCPropertyChecker(CheckerManager &Mgr) {

  Mgr.registerChecker<ObjCPropertyChecker>();

}

bool ento::shouldRegisterObjCPropertyChecker(const CheckerManager &mgr) {

  return true;

}