/*

 * Copyright (c) 2017, 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 "code/relocInfo.hpp"

#include "code/nmethod.hpp"

#include "code/icBuffer.hpp"

#include "gc/shared/barrierSet.hpp"

#include "gc/shared/barrierSetNMethod.hpp"

#include "gc/z/zGlobals.hpp"

#include "gc/z/zLock.inline.hpp"

#include "gc/z/zNMethod.hpp"

#include "gc/z/zNMethodData.hpp"

#include "gc/z/zNMethodTable.hpp"

#include "gc/z/zOopClosures.inline.hpp"

#include "gc/z/zTask.hpp"

#include "gc/z/zWorkers.hpp"

#include "logging/log.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/iterator.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "runtime/atomic.hpp"

#include "runtime/orderAccess.hpp"

#include "utilities/debug.hpp"

static ZNMethodData* gc_data(const nmethod* nm) {

  return nm->gc_data<ZNMethodData>();

}

static void set_gc_data(nmethod* nm, ZNMethodData* data) {

  return nm->set_gc_data<ZNMethodData>(data);

}

void ZNMethod::attach_gc_data(nmethod* nm) {

  GrowableArray<oop*> immediate_oops;

  bool non_immediate_oops = false;

  // Find all oops relocations

  RelocIterator iter(nm);

  while (iter.next()) {

    if (iter.type() != relocInfo::oop_type) {

      // Not an oop

      continue;

    }

    oop_Relocation* r = iter.oop_reloc();

    if (!r->oop_is_immediate()) {

      // Non-immediate oop found

      non_immediate_oops = true;

      continue;

    }

    if (r->oop_value() != NULL) {

      // Non-NULL immediate oop found. NULL oops can safely be

      // ignored since the method will be re-registered if they

      // are later patched to be non-NULL.

      immediate_oops.push(r->oop_addr());

    }

  }

  // Attach GC data to nmethod

  ZNMethodData* data = gc_data(nm);

  if (data == NULL) {

    data = new ZNMethodData();

    set_gc_data(nm, data);

  }

  // Attach oops in GC data

  ZNMethodDataOops* const new_oops = ZNMethodDataOops::create(immediate_oops, non_immediate_oops);

  ZNMethodDataOops* const old_oops = data->swap_oops(new_oops);

  ZNMethodDataOops::destroy(old_oops);

}

ZReentrantLock* ZNMethod::lock_for_nmethod(nmethod* nm) {

  return gc_data(nm)->lock();

}

void ZNMethod::log_register(const nmethod* nm) {

  LogTarget(Trace, gc, nmethod) log;

  if (!log.is_enabled()) {

    return;

  }

  const ZNMethodDataOops* const oops = gc_data(nm)->oops();

  log.print("Register NMethod: %s.%s (" PTR_FORMAT "), "

            "Compiler: %s, Oops: %d, ImmediateOops: " SIZE_FORMAT ", NonImmediateOops: %s",

            nm->method()->method_holder()->external_name(),

            nm->method()->name()->as_C_string(),

            p2i(nm),

            nm->compiler_name(),

            nm->oops_count() - 1,

            oops->immediates_count(),

            oops->has_non_immediates() ? "Yes" : "No");

  LogTarget(Trace, gc, nmethod, oops) log_oops;

  if (!log_oops.is_enabled()) {

    return;

  }

  // Print nmethod oops table

  {

    oop* const begin = nm->oops_begin();

    oop* const end = nm->oops_end();

    for (oop* p = begin; p < end; p++) {

      log_oops.print("           Oop[" SIZE_FORMAT "] " PTR_FORMAT " (%s)",

                     (p - begin), p2i(*p), (*p)->klass()->external_name());

    }

  }

  // Print nmethod immediate oops

  {

    oop** const begin = oops->immediates_begin();

    oop** const end = oops->immediates_end();

    for (oop** p = begin; p < end; p++) {

      log_oops.print("  ImmediateOop[" SIZE_FORMAT "] " PTR_FORMAT " @ " PTR_FORMAT " (%s)",

                     (p - begin), p2i(**p), p2i(*p), (**p)->klass()->external_name());

    }

  }

}

void ZNMethod::log_unregister(const nmethod* nm) {

  LogTarget(Debug, gc, nmethod) log;

  if (!log.is_enabled()) {

    return;

  }

  log.print("Unregister NMethod: %s.%s (" PTR_FORMAT ")",

            nm->method()->method_holder()->external_name(),

            nm->method()->name()->as_C_string(),

            p2i(nm));

}

void ZNMethod::register_nmethod(nmethod* nm) {

  ResourceMark rm;

  // Create and attach gc data

  attach_gc_data(nm);

  log_register(nm);

  ZNMethodTable::register_nmethod(nm);

  // Disarm nmethod entry barrier

  disarm_nmethod(nm);

}

void ZNMethod::unregister_nmethod(nmethod* nm) {

  assert(CodeCache_lock->owned_by_self(), "Lock must be held");

  if (Thread::current()->is_Code_cache_sweeper_thread()) {

    // The sweeper must wait for any ongoing iteration to complete

    // before it can unregister an nmethod.

    ZNMethodTable::wait_until_iteration_done();

  }

  ResourceMark rm;

  log_unregister(nm);

  ZNMethodTable::unregister_nmethod(nm);

}

void ZNMethod::flush_nmethod(nmethod* nm) {

  // Destroy GC data

  delete gc_data(nm);

}

void ZNMethod::disarm_nmethod(nmethod* nm) {

  BarrierSetNMethod* const bs = BarrierSet::barrier_set()->barrier_set_nmethod();

  if (bs != NULL) {

    bs->disarm(nm);

  }

}

void ZNMethod::nmethod_oops_do(nmethod* nm, OopClosure* cl) {

  // Process oops table

  {

    oop* const begin = nm->oops_begin();

    oop* const end = nm->oops_end();

    for (oop* p = begin; p < end; p++) {

      if (*p != Universe::non_oop_word()) {

        cl->do_oop(p);

      }

    }

  }

  ZNMethodDataOops* const oops = gc_data(nm)->oops();

  // Process immediate oops

  {

    oop** const begin = oops->immediates_begin();

    oop** const end = oops->immediates_end();

    for (oop** p = begin; p < end; p++) {

      if (**p != Universe::non_oop_word()) {

        cl->do_oop(*p);

      }

    }

  }

  // Process non-immediate oops

  if (oops->has_non_immediates()) {

    nm->fix_oop_relocations();

  }

}

class ZNMethodToOopsDoClosure : public NMethodClosure {

private:

  OopClosure* _cl;

public:

  ZNMethodToOopsDoClosure(OopClosure* cl) :

      _cl(cl) {}

  virtual void do_nmethod(nmethod* nm) {

    ZNMethod::nmethod_oops_do(nm, _cl);

  }

};

void ZNMethod::oops_do_begin() {

  ZNMethodTable::nmethods_do_begin();

}

void ZNMethod::oops_do_end() {

  ZNMethodTable::nmethods_do_end();

}

void ZNMethod::oops_do(OopClosure* cl) {

  ZNMethodToOopsDoClosure nmethod_cl(cl);

  ZNMethodTable::nmethods_do(&nmethod_cl);

}

class ZNMethodUnlinkClosure : public NMethodClosure {

private:

  bool          _unloading_occurred;

  volatile bool _failed;

  void set_failed() {

  }

  void unlink(nmethod* nm) {

    // Unlinking of the dependencies must happen before the

    // handshake separating unlink and purge.

    nm->flush_dependencies(false /* delete_immediately */);

    // unlink_from_method will take the CompiledMethod_lock.

    // In this case we don't strictly need it when unlinking nmethods from

    // the Method, because it is only concurrently unlinked by

    // the entry barrier, which acquires the per nmethod lock.

    nm->unlink_from_method();

    if (nm->is_osr_method()) {

      // Invalidate the osr nmethod before the handshake. The nmethod

      // will be made unloaded after the handshake. Then invalidate_osr_method()

      // will be called again, which will be a no-op.

      nm->invalidate_osr_method();

    }

  }

public:

  ZNMethodUnlinkClosure(bool unloading_occurred) :

      _unloading_occurred(unloading_occurred),

      _failed(false) {}

  virtual void do_nmethod(nmethod* nm) {

    if (failed()) {

      return;

    }

    if (!nm->is_alive()) {

      return;

    }

    if (nm->is_unloading()) {

      ZLocker<ZReentrantLock> locker(ZNMethod::lock_for_nmethod(nm));

      unlink(nm);

      return;

    }

    ZLocker<ZReentrantLock> locker(ZNMethod::lock_for_nmethod(nm));

    // Heal oops and disarm

    ZNMethodOopClosure cl;

    ZNMethod::nmethod_oops_do(nm, &cl);

    ZNMethod::disarm_nmethod(nm);

    // Clear compiled ICs and exception caches

    if (!nm->unload_nmethod_caches(_unloading_occurred)) {

      set_failed();

    }

  }

  bool failed() const {

    return Atomic::load(&_failed);

  }

};

class ZNMethodUnlinkTask : public ZTask {

private:

  ZNMethodUnlinkClosure _cl;

  ICRefillVerifier*     _verifier;

public:

  ZNMethodUnlinkTask(bool unloading_occurred, ICRefillVerifier* verifier) :

      ZTask("ZNMethodUnlinkTask"),

      _cl(unloading_occurred),

      _verifier(verifier) {

    ZNMethodTable::nmethods_do_begin();

  }

  ~ZNMethodUnlinkTask() {

    ZNMethodTable::nmethods_do_end();

  }

  virtual void work() {

    ICRefillVerifierMark mark(_verifier);

    ZNMethodTable::nmethods_do(&_cl);

  }

  bool success() const {

    return !_cl.failed();

  }

};

void ZNMethod::unlink(ZWorkers* workers, bool unloading_occurred) {

  for (;;) {

    ICRefillVerifier verifier;

    {

      ZNMethodUnlinkTask task(unloading_occurred, &verifier);

      workers->run_concurrent(&task);

      if (task.success()) {

        return;

      }

    }

    // Cleaning failed because we ran out of transitional IC stubs,

    // so we have to refill and try again. Refilling requires taking

    // a safepoint, so we temporarily leave the suspendible thread set.

    SuspendibleThreadSetLeaver sts;

    InlineCacheBuffer::refill_ic_stubs();

  }

}

class ZNMethodPurgeClosure : public NMethodClosure {

public:

  virtual void do_nmethod(nmethod* nm) {

    if (nm->is_alive() && nm->is_unloading()) {

      nm->make_unloaded();

    }

  }

};

class ZNMethodPurgeTask : public ZTask {

private:

  ZNMethodPurgeClosure _cl;

public:

  ZNMethodPurgeTask() :

      ZTask("ZNMethodPurgeTask"),

      _cl() {

    ZNMethodTable::nmethods_do_begin();

  }

  ~ZNMethodPurgeTask() {

    ZNMethodTable::nmethods_do_end();

  }

  virtual void work() {

    ZNMethodTable::nmethods_do(&_cl);

  }

};

void ZNMethod::purge(ZWorkers* workers) {

  ZNMethodPurgeTask task;

  workers->run_concurrent(&task);

}