/*
 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

#include "precompiled.hpp"
#include "classfile/classLoaderData.hpp"
#include "gc/z/zAddress.hpp"
#include "gc/z/zHeap.inline.hpp"
#include "gc/z/zOop.hpp"
#include "gc/z/zResurrection.hpp"
#include "gc/z/zRootsIterator.hpp"
#include "gc/z/zStat.hpp"
#include "gc/z/zVerify.hpp"
#include "memory/iterator.inline.hpp"
#include "oops/oop.hpp"

#define ZBAD_OOP_ARG(o, p)   "Bad oop " PTR_FORMAT " found at " PTR_FORMAT, p2i(o), p2i(p)

static void verify_oop(oop* p) {
  const oop o = RawAccess<>::oop_load(p);
  if (o != NULL) {
    const uintptr_t addr = ZOop::to_address(o);
    guarantee(ZAddress::is_good(addr), ZBAD_OOP_ARG(o, p));
    guarantee(oopDesc::is_oop(ZOop::from_address(addr)), ZBAD_OOP_ARG(o, p));
  }
}

static void verify_possibly_weak_oop(oop* p) {
  const oop o = RawAccess<>::oop_load(p);
  if (o != NULL) {
    const uintptr_t addr = ZOop::to_address(o);
    guarantee(ZAddress::is_good(addr) || ZAddress::is_finalizable_good(addr), ZBAD_OOP_ARG(o, p));
    guarantee(oopDesc::is_oop(ZOop::from_address(ZAddress::good(addr))), ZBAD_OOP_ARG(o, p));
  }
}

class ZVerifyRootClosure : public ZRootsIteratorClosure {
public:
  virtual void do_oop(oop* p) {
    verify_oop(p);
  }

  virtual void do_oop(narrowOop*) {
    ShouldNotReachHere();
  }
};

class ZVerifyOopClosure : public ClaimMetadataVisitingOopIterateClosure, public ZRootsIteratorClosure  {
private:
  const bool _verify_weaks;

public:
  ZVerifyOopClosure(bool verify_weaks) :
      ClaimMetadataVisitingOopIterateClosure(ClassLoaderData::_claim_other),
      _verify_weaks(verify_weaks) {}

  virtual void do_oop(oop* p) {
    if (_verify_weaks) {
      verify_possibly_weak_oop(p);
    } else {
      // We should never encounter finalizable oops through strong
      // paths. This assumes we have only visited strong roots.
      verify_oop(p);
    }
  }

  virtual void do_oop(narrowOop* p) {
    ShouldNotReachHere();
  }

  virtual ReferenceIterationMode reference_iteration_mode() {
    return _verify_weaks ? DO_FIELDS : DO_FIELDS_EXCEPT_REFERENT;
  }

#ifdef ASSERT
  // Verification handled by the closure itself
  virtual bool should_verify_oops() {
    return false;
  }
#endif
};

template <typename RootsIterator>
void ZVerify::roots() {
  assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
  assert(!ZResurrection::is_blocked(), "Invalid phase");

  if (ZVerifyRoots) {
    ZVerifyRootClosure cl;
    RootsIterator iter;
    iter.oops_do(&cl);
  }
}

void ZVerify::roots_strong() {
  roots<ZRootsIterator>();
}

void ZVerify::roots_weak() {
  roots<ZWeakRootsIterator>();
}

void ZVerify::roots_concurrent_strong() {
  roots<ZConcurrentRootsIteratorClaimNone>();
}

void ZVerify::roots_concurrent_weak() {
  roots<ZConcurrentWeakRootsIterator>();
}

void ZVerify::roots(bool verify_weaks) {
  roots_strong();
  roots_concurrent_strong();
  if (verify_weaks) {
    roots_weak();
    roots_concurrent_weak();
  }
}

void ZVerify::objects(bool verify_weaks) {
  assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
  assert(ZGlobalPhase == ZPhaseMarkCompleted, "Invalid phase");
  assert(!ZResurrection::is_blocked(), "Invalid phase");

  if (ZVerifyObjects) {
    ZVerifyOopClosure cl(verify_weaks);
    ObjectToOopClosure object_cl(&cl);
    ZHeap::heap()->object_iterate(&object_cl, verify_weaks);
  }
}

void ZVerify::roots_and_objects(bool verify_weaks) {
  roots(verify_weaks);
  objects(verify_weaks);
}

void ZVerify::before_zoperation() {
  // Verify strong roots
  ZStatTimerDisable disable;
  roots_strong();
}

void ZVerify::after_mark() {
  // Verify all strong roots and strong references
  ZStatTimerDisable disable;
  roots_and_objects(false /* verify_weaks */);
}

void ZVerify::after_weak_processing() {
  // Verify all roots and all references
  ZStatTimerDisable disable;
  roots_and_objects(true /* verify_weaks */);
}