//=- NSAutoreleasePoolChecker.cpp --------------------------------*- 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 file defines a NSAutoreleasePoolChecker, a small checker that warns

//  about subpar uses of NSAutoreleasePool.  Note that while the check itself

//  (in its current form) could be written as a flow-insensitive check, in

//  can be potentially enhanced in the future with flow-sensitive information.

//  It is also a good example of the CheckerVisitor interface.

//

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

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

#include "clang/AST/Decl.h"

#include "clang/AST/DeclObjC.h"

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

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

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

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

#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"

using namespace clang;

using namespace ento;

namespace {

class NSAutoreleasePoolChecker

  : public Checker<check::PreObjCMessage> {

  mutable std::unique_ptr<BugType> BT;

  mutable Selector releaseS;

public:

  void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;

};

} // end anonymous namespace

void NSAutoreleasePoolChecker::checkPreObjCMessage(const ObjCMethodCall &msg,

                                                   CheckerContext &C) const {

  if (!msg.isInstanceMessage())

    return;

  const ObjCInterfaceDecl *OD = msg.getReceiverInterface();

  if (!OD)

    return;

  if (!OD->getIdentifier()->isStr("NSAutoreleasePool"))

    return;

  if (releaseS.isNull())

    releaseS = GetNullarySelector("release", C.getASTContext());

  // Sending 'release' message?

  if (msg.getSelector() != releaseS)

    return;

  if (!BT)

    BT.reset(new BugType(this, "Use -drain instead of -release",

                         "API Upgrade (Apple)"));

  ExplodedNode *N = C.generateNonFatalErrorNode();

  if (!N) {

    assert(0);

    return;

  }

  auto Report = std::make_unique<PathSensitiveBugReport>(

      *BT,

      "Use -drain instead of -release when using NSAutoreleasePool and "

      "garbage collection",

      N);

  Report->addRange(msg.getSourceRange());

  C.emitReport(std::move(Report));

}

void ento::registerNSAutoreleasePoolChecker(CheckerManager &mgr) {

  mgr.registerChecker<NSAutoreleasePoolChecker>();

}

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

  const LangOptions &LO = mgr.getLangOpts();

  return LO.getGC() != LangOptions::NonGC;

}