/*

 * Copyright (c) 1997, 2015, 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 "compiler/compileBroker.hpp"

#include "gc/serial/markSweep.inline.hpp"

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

#include "gc/shared/gcTimer.hpp"

#include "gc/shared/gcTrace.hpp"

#include "gc/shared/specialized_oop_closures.hpp"

#include "memory/iterator.inline.hpp"

#include "oops/instanceClassLoaderKlass.inline.hpp"

#include "oops/instanceKlass.inline.hpp"

#include "oops/instanceMirrorKlass.inline.hpp"

#include "oops/instanceRefKlass.inline.hpp"

#include "oops/methodData.hpp"

#include "oops/objArrayKlass.inline.hpp"

#include "oops/oop.inline.hpp"

#include "utilities/macros.hpp"

#include "utilities/stack.inline.hpp"

#if INCLUDE_ALL_GCS

#include "gc/g1/g1StringDedup.hpp"

#endif // INCLUDE_ALL_GCS

uint                    MarkSweep::_total_invocations = 0;

Stack<oop, mtGC>              MarkSweep::_marking_stack;

Stack<ObjArrayTask, mtGC>     MarkSweep::_objarray_stack;

Stack<oop, mtGC>              MarkSweep::_preserved_oop_stack;

Stack<markOop, mtGC>          MarkSweep::_preserved_mark_stack;

size_t                  MarkSweep::_preserved_count = 0;

size_t                  MarkSweep::_preserved_count_max = 0;

PreservedMark*          MarkSweep::_preserved_marks = NULL;

ReferenceProcessor*     MarkSweep::_ref_processor   = NULL;

STWGCTimer*             MarkSweep::_gc_timer        = NULL;

SerialOldTracer*        MarkSweep::_gc_tracer       = NULL;

MarkSweep::FollowRootClosure  MarkSweep::follow_root_closure;

MarkAndPushClosure            MarkSweep::mark_and_push_closure;

CLDToOopClosure               MarkSweep::follow_cld_closure(&mark_and_push_closure);

CLDToOopClosure               MarkSweep::adjust_cld_closure(&adjust_pointer_closure);

inline void MarkSweep::mark_object(oop obj) {

#if INCLUDE_ALL_GCS

  if (G1StringDedup::is_enabled()) {

    // We must enqueue the object before it is marked

    // as we otherwise can't read the object's age.

    G1StringDedup::enqueue_from_mark(obj);

  }

#endif

  // some marks may contain information we need to preserve so we store them away

  // and overwrite the mark.  We'll restore it at the end of markSweep.

  markOop mark = obj->mark();

  obj->set_mark(markOopDesc::prototype()->set_marked());

  if (mark->must_be_preserved(obj)) {

    preserve_mark(obj, mark);

  }

}

template <class T> inline void MarkSweep::mark_and_push(T* p) {

  T heap_oop = oopDesc::load_heap_oop(p);

  if (!oopDesc::is_null(heap_oop)) {

    oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);

    if (!obj->mark()->is_marked() &&

        !is_archive_object(obj)) {

      mark_object(obj);

      _marking_stack.push(obj);

    }

  }

}

inline void MarkSweep::follow_klass(Klass* klass) {

  oop op = klass->klass_holder();

  MarkSweep::mark_and_push(&op);

}

inline void MarkSweep::follow_cld(ClassLoaderData* cld) {

  MarkSweep::follow_cld_closure.do_cld(cld);

}

template <typename T>

inline void MarkAndPushClosure::do_oop_nv(T* p)                 { MarkSweep::mark_and_push(p); }

void MarkAndPushClosure::do_oop(oop* p)                         { do_oop_nv(p); }

void MarkAndPushClosure::do_oop(narrowOop* p)                   { do_oop_nv(p); }

inline bool MarkAndPushClosure::do_metadata_nv()                { return true; }

bool MarkAndPushClosure::do_metadata()                          { return do_metadata_nv(); }

inline void MarkAndPushClosure::do_klass_nv(Klass* k)           { MarkSweep::follow_klass(k); }

void MarkAndPushClosure::do_klass(Klass* k)                     { do_klass_nv(k); }

inline void MarkAndPushClosure::do_cld_nv(ClassLoaderData* cld) { MarkSweep::follow_cld(cld); }

void MarkAndPushClosure::do_cld(ClassLoaderData* cld)           { do_cld_nv(cld); }

template <class T> inline void MarkSweep::KeepAliveClosure::do_oop_work(T* p) {

  mark_and_push(p);

}

void MarkSweep::push_objarray(oop obj, size_t index) {

  ObjArrayTask task(obj, index);

  assert(task.is_valid(), "bad ObjArrayTask");

  _objarray_stack.push(task);

}

inline void MarkSweep::follow_array(objArrayOop array) {

  MarkSweep::follow_klass(array->klass());

  // Don't push empty arrays to avoid unnecessary work.

  if (array->length() > 0) {

    MarkSweep::push_objarray(array, 0);

  }

}

inline void MarkSweep::follow_object(oop obj) {

  assert(obj->is_gc_marked(), "should be marked");

  if (obj->is_objArray()) {

    // Handle object arrays explicitly to allow them to

    // be split into chunks if needed.

    MarkSweep::follow_array((objArrayOop)obj);

  } else {

    obj->oop_iterate(&mark_and_push_closure);

  }

}

void MarkSweep::follow_array_chunk(objArrayOop array, int index) {

  const int len = array->length();

  const int beg_index = index;

  assert(beg_index < len || len == 0, "index too large");

  const int stride = MIN2(len - beg_index, (int) ObjArrayMarkingStride);

  const int end_index = beg_index + stride;

  array->oop_iterate_range(&mark_and_push_closure, beg_index, end_index);

  if (end_index < len) {

    MarkSweep::push_objarray(array, end_index); // Push the continuation.

  }

}

void MarkSweep::follow_stack() {

  do {

    while (!_marking_stack.is_empty()) {

      oop obj = _marking_stack.pop();

      assert (obj->is_gc_marked(), "p must be marked");

      follow_object(obj);

    }

    // Process ObjArrays one at a time to avoid marking stack bloat.

    if (!_objarray_stack.is_empty()) {

      ObjArrayTask task = _objarray_stack.pop();

      follow_array_chunk(objArrayOop(task.obj()), task.index());

    }

  } while (!_marking_stack.is_empty() || !_objarray_stack.is_empty());

}

MarkSweep::FollowStackClosure MarkSweep::follow_stack_closure;

void MarkSweep::FollowStackClosure::do_void() { follow_stack(); }

template <class T> inline void MarkSweep::follow_root(T* p) {

  assert(!Universe::heap()->is_in_reserved(p),

         "roots shouldn't be things within the heap");

  T heap_oop = oopDesc::load_heap_oop(p);

  if (!oopDesc::is_null(heap_oop)) {

    oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);

    if (!obj->mark()->is_marked() &&

        !is_archive_object(obj)) {

      mark_object(obj);

      follow_object(obj);

    }

  }

  follow_stack();

}

void MarkSweep::FollowRootClosure::do_oop(oop* p)       { follow_root(p); }

void MarkSweep::FollowRootClosure::do_oop(narrowOop* p) { follow_root(p); }

void PreservedMark::adjust_pointer() {

  MarkSweep::adjust_pointer(&_obj);

}

void PreservedMark::restore() {

  _obj->set_mark(_mark);

}

// We preserve the mark which should be replaced at the end and the location

// that it will go.  Note that the object that this markOop belongs to isn't

// currently at that address but it will be after phase4

void MarkSweep::preserve_mark(oop obj, markOop mark) {

  // We try to store preserved marks in the to space of the new generation since

  // this is storage which should be available.  Most of the time this should be

  // sufficient space for the marks we need to preserve but if it isn't we fall

  // back to using Stacks to keep track of the overflow.

  if (_preserved_count < _preserved_count_max) {

    _preserved_marks[_preserved_count++].init(obj, mark);

  } else {

    _preserved_mark_stack.push(mark);

    _preserved_oop_stack.push(obj);

  }

}

void MarkSweep::set_ref_processor(ReferenceProcessor* rp) {

  _ref_processor = rp;

  mark_and_push_closure.set_ref_processor(_ref_processor);

}

MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure;

template <typename T>

void MarkSweep::AdjustPointerClosure::do_oop_nv(T* p)      { adjust_pointer(p); }

void MarkSweep::AdjustPointerClosure::do_oop(oop* p)       { do_oop_nv(p); }

void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { do_oop_nv(p); }

void MarkSweep::adjust_marks() {

  assert( _preserved_oop_stack.size() == _preserved_mark_stack.size(),

         "inconsistent preserved oop stacks");

  // adjust the oops we saved earlier

  for (size_t i = 0; i < _preserved_count; i++) {

    _preserved_marks[i].adjust_pointer();

  }

  // deal with the overflow stack

  StackIterator<oop, mtGC> iter(_preserved_oop_stack);

  while (!iter.is_empty()) {

    oop* p = iter.next_addr();

    adjust_pointer(p);

  }

}

void MarkSweep::restore_marks() {

  assert(_preserved_oop_stack.size() == _preserved_mark_stack.size(),

         "inconsistent preserved oop stacks");

  // restore the marks we saved earlier

  for (size_t i = 0; i < _preserved_count; i++) {

    _preserved_marks[i].restore();

  }

  // deal with the overflow

  while (!_preserved_oop_stack.is_empty()) {

    oop obj       = _preserved_oop_stack.pop();

    markOop mark  = _preserved_mark_stack.pop();

    obj->set_mark(mark);

  }

}

MarkSweep::IsAliveClosure   MarkSweep::is_alive;

bool MarkSweep::IsAliveClosure::do_object_b(oop p) { return p->is_gc_marked() || is_archive_object(p); }

MarkSweep::KeepAliveClosure MarkSweep::keep_alive;

void MarkSweep::KeepAliveClosure::do_oop(oop* p)       { MarkSweep::KeepAliveClosure::do_oop_work(p); }

void MarkSweep::KeepAliveClosure::do_oop(narrowOop* p) { MarkSweep::KeepAliveClosure::do_oop_work(p); }

void marksweep_init() {

  MarkSweep::_gc_timer = new (ResourceObj::C_HEAP, mtGC) STWGCTimer();

  MarkSweep::_gc_tracer = new (ResourceObj::C_HEAP, mtGC) SerialOldTracer();

}

int InstanceKlass::oop_ms_adjust_pointers(oop obj) {

  int size = size_helper();

  oop_oop_iterate_oop_maps<true>(obj, &MarkSweep::adjust_pointer_closure);

  return size;

}

int InstanceMirrorKlass::oop_ms_adjust_pointers(oop obj) {

  int size = oop_size(obj);

  InstanceKlass::oop_ms_adjust_pointers(obj);

  oop_oop_iterate_statics<true>(obj, &MarkSweep::adjust_pointer_closure);

  return size;

}

int InstanceClassLoaderKlass::oop_ms_adjust_pointers(oop obj) {

  return InstanceKlass::oop_ms_adjust_pointers(obj);

}

#ifdef ASSERT

template <class T> static void trace_reference_gc(const char *s, oop obj,

                                                  T* referent_addr,

                                                  T* next_addr,

                                                  T* discovered_addr) {

}

#endif

template <class T> void static adjust_object_specialized(oop obj) {

  T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);

  MarkSweep::adjust_pointer(referent_addr);

  T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);

  MarkSweep::adjust_pointer(next_addr);

  T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);

  MarkSweep::adjust_pointer(discovered_addr);

  debug_only(trace_reference_gc("InstanceRefKlass::oop_ms_adjust_pointers", obj,

                                referent_addr, next_addr, discovered_addr);)

}

int InstanceRefKlass::oop_ms_adjust_pointers(oop obj) {

  int size = size_helper();

  InstanceKlass::oop_ms_adjust_pointers(obj);

  if (UseCompressedOops) {

    adjust_object_specialized<narrowOop>(obj);

  } else {

    adjust_object_specialized<oop>(obj);

  }

  return size;

}

int ObjArrayKlass::oop_ms_adjust_pointers(oop obj) {

  assert(obj->is_objArray(), "obj must be obj array");

  objArrayOop a = objArrayOop(obj);

  // Get size before changing pointers.

  // Don't call size() or oop_size() since that is a virtual call.

  int size = a->object_size();

  oop_oop_iterate_elements<true>(a, &MarkSweep::adjust_pointer_closure);

  return size;

}

int TypeArrayKlass::oop_ms_adjust_pointers(oop obj) {

  assert(obj->is_typeArray(), "must be a type array");

  typeArrayOop t = typeArrayOop(obj);

  // Performance tweak: We skip iterating over the klass pointer since we

  // know that Universe::TypeArrayKlass never moves.

  return t->object_size();

}

// Generate MS specialized oop_oop_iterate functions.

SPECIALIZED_OOP_OOP_ITERATE_CLOSURES_MS(ALL_KLASS_OOP_OOP_ITERATE_DEFN)