/*

 * Copyright (c) 2015, 2019, Red Hat, Inc. All rights reserved.

 *

 * 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/classLoaderDataGraph.hpp"

#include "classfile/stringTable.hpp"

#include "classfile/systemDictionary.hpp"

#include "code/codeCache.hpp"

#include "gc/shenandoah/shenandoahClosures.inline.hpp"

#include "gc/shenandoah/shenandoahRootProcessor.hpp"

#include "gc/shenandoah/shenandoahHeap.hpp"

#include "gc/shenandoah/shenandoahPhaseTimings.hpp"

#include "gc/shenandoah/shenandoahStringDedup.hpp"

#include "gc/shenandoah/shenandoahTimingTracker.hpp"

#include "gc/shenandoah/shenandoahUtils.hpp"

#include "gc/shenandoah/shenandoahVMOperations.hpp"

#include "gc/shared/weakProcessor.inline.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/iterator.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/thread.hpp"

#include "services/management.hpp"

ShenandoahRootProcessor::ShenandoahRootProcessor(ShenandoahHeap* heap, uint n_workers,

                                                 ShenandoahPhaseTimings::Phase phase) :

  _process_strong_tasks(new SubTasksDone(SHENANDOAH_RP_PS_NumElements)),

  _srs(n_workers),

  _phase(phase),

  _coderoots_all_iterator(ShenandoahCodeRoots::iterator()),

  _weak_processor_timings(n_workers),

  _weak_processor_task(&_weak_processor_timings, n_workers),

  _processed_weak_roots(false) {

  heap->phase_timings()->record_workers_start(_phase);

  if (ShenandoahStringDedup::is_enabled()) {

    StringDedup::gc_prologue(false);

  }

}

ShenandoahRootProcessor::~ShenandoahRootProcessor() {

  delete _process_strong_tasks;

  if (ShenandoahStringDedup::is_enabled()) {

    StringDedup::gc_epilogue();

  }

  if (_processed_weak_roots) {

    assert(_weak_processor_timings.max_threads() == n_workers(), "Must match");

    ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

    ShenandoahTimingConverter::weak_processing_timing_to_shenandoah_timing(&_weak_processor_timings,

                                                                           worker_times);

  }

  ShenandoahHeap::heap()->phase_timings()->record_workers_end(_phase);

}

void ShenandoahRootProcessor::process_all_roots_slow(OopClosure* oops) {

  CLDToOopClosure clds(oops, ClassLoaderData::_claim_strong);

  CodeBlobToOopClosure blobs(oops, !CodeBlobToOopClosure::FixRelocations);

  CodeCache::blobs_do(&blobs);

  ClassLoaderDataGraph::cld_do(&clds);

  Universe::oops_do(oops);

  Management::oops_do(oops);

  JvmtiExport::oops_do(oops);

  JNIHandles::oops_do(oops);

  ObjectSynchronizer::oops_do(oops);

  SystemDictionary::oops_do(oops);

  AlwaysTrueClosure always_true;

  WeakProcessor::weak_oops_do(&always_true, oops);

  if (ShenandoahStringDedup::is_enabled()) {

    ShenandoahStringDedup::oops_do_slow(oops);

  }

  // Do thread roots the last. This allows verification code to find

  // any broken objects from those special roots first, not the accidental

  // dangling reference from the thread root.

  Threads::possibly_parallel_oops_do(false, oops, &blobs);

}

void ShenandoahRootProcessor::process_strong_roots(OopClosure* oops,

                                                   CLDClosure* clds,

                                                   CodeBlobClosure* blobs,

                                                   ThreadClosure* thread_cl,

                                                   uint worker_id) {

  process_java_roots(oops, clds, NULL, blobs, thread_cl, worker_id);

  process_vm_roots(oops, worker_id);

  _process_strong_tasks->all_tasks_completed(n_workers());

}

void ShenandoahRootProcessor::process_all_roots(OopClosure* oops,

                                                CLDClosure* clds,

                                                CodeBlobClosure* blobs,

                                                ThreadClosure* thread_cl,

                                                uint worker_id) {

  ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

  process_java_roots(oops, clds, clds, blobs, thread_cl, worker_id);

  process_vm_roots(oops, worker_id);

  if (blobs != NULL) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::CodeCacheRoots, worker_id);

    _coderoots_all_iterator.possibly_parallel_blobs_do(blobs);

  }

  _process_strong_tasks->all_tasks_completed(n_workers());

}

class ShenandoahParallelOopsDoThreadClosure : public ThreadClosure {

private:

  OopClosure* _f;

  CodeBlobClosure* _cf;

  ThreadClosure* _thread_cl;

public:

  ShenandoahParallelOopsDoThreadClosure(OopClosure* f, CodeBlobClosure* cf, ThreadClosure* thread_cl) :

    _f(f), _cf(cf), _thread_cl(thread_cl) {}

  void do_thread(Thread* t) {

    if (_thread_cl != NULL) {

      _thread_cl->do_thread(t);

    }

    t->oops_do(_f, _cf);

  }

};

void ShenandoahRootProcessor::process_java_roots(OopClosure* strong_roots,

                                                 CLDClosure* strong_clds,

                                                 CLDClosure* weak_clds,

                                                 CodeBlobClosure* strong_code,

                                                 ThreadClosure* thread_cl,

                                                 uint worker_id)

{

  ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

  // Iterating over the CLDG and the Threads are done early to allow us to

  // first process the strong CLDs and nmethods and then, after a barrier,

  // let the thread process the weak CLDs and nmethods.

  {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::CLDGRoots, worker_id);

    _cld_iterator.root_cld_do(strong_clds, weak_clds);

  }

  {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ThreadRoots, worker_id);

    bool is_par = n_workers() > 1;

    ResourceMark rm;

    ShenandoahParallelOopsDoThreadClosure cl(strong_roots, strong_code, thread_cl);

    Threads::possibly_parallel_threads_do(is_par, &cl);

  }

}

void ShenandoahRootProcessor::process_vm_roots(OopClosure* strong_roots,

                                               uint worker_id) {

  ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

  if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_Universe_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::UniverseRoots, worker_id);

    Universe::oops_do(strong_roots);

  }

  if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_JNIHandles_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::JNIRoots, worker_id);

    JNIHandles::oops_do(strong_roots);

  }

  if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_Management_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ManagementRoots, worker_id);

    Management::oops_do(strong_roots);

  }

  if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_jvmti_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::JVMTIRoots, worker_id);

    JvmtiExport::oops_do(strong_roots);

  }

  if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_SystemDictionary_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::SystemDictionaryRoots, worker_id);

    SystemDictionary::oops_do(strong_roots);

  }

  {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ObjectSynchronizerRoots, worker_id);

    if (_process_strong_tasks->try_claim_task(SHENANDOAH_RP_PS_ObjectSynchronizer_oops_do)) {

      ObjectSynchronizer::oops_do(strong_roots);

    }

  }

}

uint ShenandoahRootProcessor::n_workers() const {

  return _srs.n_threads();

}

ShenandoahRootEvacuator::ShenandoahRootEvacuator(ShenandoahHeap* heap, uint n_workers, ShenandoahPhaseTimings::Phase phase) :

  _evacuation_tasks(new SubTasksDone(SHENANDOAH_EVAC_NumElements)),

  _srs(n_workers),

  _phase(phase),

  _coderoots_cset_iterator(ShenandoahCodeRoots::cset_iterator()),

  _weak_processor_timings(n_workers),

  _weak_processor_task(&_weak_processor_timings, n_workers) {

  heap->phase_timings()->record_workers_start(_phase);

  if (ShenandoahStringDedup::is_enabled()) {

    StringDedup::gc_prologue(false);

  }

}

ShenandoahRootEvacuator::~ShenandoahRootEvacuator() {

  delete _evacuation_tasks;

  if (ShenandoahStringDedup::is_enabled()) {

    StringDedup::gc_epilogue();

  }

  ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

  assert(_weak_processor_timings.max_threads() == n_workers(), "Must match");

  ShenandoahTimingConverter::weak_processing_timing_to_shenandoah_timing(&_weak_processor_timings,

                                                                         worker_times);

  ShenandoahHeap::heap()->phase_timings()->record_workers_end(_phase);

}

void ShenandoahRootEvacuator::process_evacuate_roots(OopClosure* oops,

                                                     CodeBlobClosure* blobs,

                                                     uint worker_id) {

  AlwaysTrueClosure always_true;

  ShenandoahWorkerTimings* worker_times = ShenandoahHeap::heap()->phase_timings()->worker_times();

  {

    bool is_par = n_workers() > 1;

    ResourceMark rm;

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ThreadRoots, worker_id);

    Threads::possibly_parallel_oops_do(is_par, oops, NULL);

  }

  {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::CLDGRoots, worker_id);

    CLDToOopClosure clds(oops, ClassLoaderData::_claim_strong);

    _cld_iterator.root_cld_do(&clds, &clds);

  }

  if (blobs != NULL) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::CodeCacheRoots, worker_id);

    _coderoots_cset_iterator.possibly_parallel_blobs_do(blobs);

  }

  if (ShenandoahStringDedup::is_enabled()) {

    ShenandoahStringDedup::parallel_oops_do(&always_true, oops, worker_id);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_Universe_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::UniverseRoots, worker_id);

    Universe::oops_do(oops);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_Management_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ManagementRoots, worker_id);

    Management::oops_do(oops);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_jvmti_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::JVMTIRoots, worker_id);

    JvmtiExport::oops_do(oops);

    ShenandoahForwardedIsAliveClosure is_alive;

    JvmtiExport::weak_oops_do(&is_alive, oops);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_JNIHandles_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::JNIRoots, worker_id);

    JNIHandles::oops_do(oops);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_SystemDictionary_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::SystemDictionaryRoots, worker_id);

    SystemDictionary::oops_do(oops);

  }

  if (_evacuation_tasks->try_claim_task(SHENANDOAH_EVAC_ObjectSynchronizer_oops_do)) {

    ShenandoahWorkerTimingsTracker timer(worker_times, ShenandoahPhaseTimings::ObjectSynchronizerRoots, worker_id);

    ObjectSynchronizer::oops_do(oops);

  }

  _weak_processor_task.work<AlwaysTrueClosure, OopClosure>(worker_id, &always_true, oops);

}

uint ShenandoahRootEvacuator::n_workers() const {

  return _srs.n_threads();

}

// Implemenation of ParallelCLDRootIterator

ParallelCLDRootIterator::ParallelCLDRootIterator() {

  assert(SafepointSynchronize::is_at_safepoint(), "Must at safepoint");

  ClassLoaderDataGraph::clear_claimed_marks();

}

void ParallelCLDRootIterator::root_cld_do(CLDClosure* strong, CLDClosure* weak) {

    ClassLoaderDataGraph::roots_cld_do(strong, weak);

}