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 /*

  * Copyright (c) 1997, 2009, 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 "incls/_precompiled.incl"

 #include "incls/_markSweep.cpp.incl"

 GrowableArray<oop>*          MarkSweep::_marking_stack = NULL;

 GrowableArray<ObjArrayTask>* MarkSweep::_objarray_stack = NULL;

 GrowableArray<Klass*>*       MarkSweep::_revisit_klass_stack = NULL;

 GrowableArray<DataLayout*>*  MarkSweep::_revisit_mdo_stack = NULL;

 GrowableArray<oop>*     MarkSweep::_preserved_oop_stack = NULL;

 GrowableArray<markOop>* MarkSweep::_preserved_mark_stack= NULL;

 size_t                  MarkSweep::_preserved_count = 0;

 size_t                  MarkSweep::_preserved_count_max = 0;

 PreservedMark*          MarkSweep::_preserved_marks = NULL;

 ReferenceProcessor*     MarkSweep::_ref_processor   = NULL;

 #ifdef VALIDATE_MARK_SWEEP

 GrowableArray<void*>*   MarkSweep::_root_refs_stack = NULL;

 GrowableArray<oop> *    MarkSweep::_live_oops = NULL;

 GrowableArray<oop> *    MarkSweep::_live_oops_moved_to = NULL;

 GrowableArray<size_t>*  MarkSweep::_live_oops_size = NULL;

 size_t                  MarkSweep::_live_oops_index = 0;

 size_t                  MarkSweep::_live_oops_index_at_perm = 0;

 GrowableArray<void*>*   MarkSweep::_other_refs_stack = NULL;

 GrowableArray<void*>*   MarkSweep::_adjusted_pointers = NULL;

 bool                         MarkSweep::_pointer_tracking = false;

 bool                         MarkSweep::_root_tracking = true;

 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops = NULL;

 GrowableArray<HeapWord*>* MarkSweep::_cur_gc_live_oops_moved_to = NULL;

 GrowableArray<size_t>   * MarkSweep::_cur_gc_live_oops_size = NULL;

 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops = NULL;

 GrowableArray<HeapWord*>* MarkSweep::_last_gc_live_oops_moved_to = NULL;

 GrowableArray<size_t>   * MarkSweep::_last_gc_live_oops_size = NULL;

 #endif

 void MarkSweep::revisit_weak_klass_link(Klass* k) {

   _revisit_klass_stack->push(k);

 }

 void MarkSweep::follow_weak_klass_links() {

   // All klasses on the revisit stack are marked at this point.

   // Update and follow all subklass, sibling and implementor links.

   if (PrintRevisitStats) {

     gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());

     gclog_or_tty->print_cr("Revisit klass stack length = %d", _revisit_klass_stack->length());

   }

   for (int i = 0; i < _revisit_klass_stack->length(); i++) {

     _revisit_klass_stack->at(i)->follow_weak_klass_links(&is_alive,&keep_alive);

   }

   follow_stack();

 }

 void MarkSweep::revisit_mdo(DataLayout* p) {

   _revisit_mdo_stack->push(p);

 }

 void MarkSweep::follow_mdo_weak_refs() {

   // All strongly reachable oops have been marked at this point;

   // we can visit and clear any weak references from MDO's which

   // we memoized during the strong marking phase.

   assert(_marking_stack->is_empty(), "Marking stack should be empty");

   if (PrintRevisitStats) {

     gclog_or_tty->print_cr("#classes in system dictionary = %d", SystemDictionary::number_of_classes());

     gclog_or_tty->print_cr("Revisit MDO stack length = %d", _revisit_mdo_stack->length());

   }

   for (int i = 0; i < _revisit_mdo_stack->length(); i++) {

     _revisit_mdo_stack->at(i)->follow_weak_refs(&is_alive);

   }

   follow_stack();

 }

 MarkSweep::FollowRootClosure  MarkSweep::follow_root_closure;

 CodeBlobToOopClosure MarkSweep::follow_code_root_closure(&MarkSweep::follow_root_closure, /*do_marking=*/ true);

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

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

 MarkSweep::MarkAndPushClosure MarkSweep::mark_and_push_closure;

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

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

 void MarkSweep::follow_stack() {

   do {

     while (!_marking_stack->is_empty()) {

       oop obj = _marking_stack->pop();

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

       obj->follow_contents();

     }

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

     if (!_objarray_stack->is_empty()) {

       ObjArrayTask task = _objarray_stack->pop();

       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();

       k->oop_follow_contents(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(); }

 // 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 in using

   // GrowableArrays to keep track of the overflow.

   if (_preserved_count < _preserved_count_max) {

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

   } else {

     if (_preserved_mark_stack == NULL) {

       _preserved_mark_stack = new (ResourceObj::C_HEAP) GrowableArray<markOop>(40, true);

       _preserved_oop_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(40, true);

     }

     _preserved_mark_stack->push(mark);

     _preserved_oop_stack->push(obj);

   }

 }

 MarkSweep::AdjustPointerClosure MarkSweep::adjust_root_pointer_closure(true);

 MarkSweep::AdjustPointerClosure MarkSweep::adjust_pointer_closure(false);

 void MarkSweep::AdjustPointerClosure::do_oop(oop* p)       { adjust_pointer(p, _is_root); }

 void MarkSweep::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p, _is_root); }

 void MarkSweep::adjust_marks() {

   assert(_preserved_oop_stack == NULL ||

          _preserved_oop_stack->length() == _preserved_mark_stack->length(),

          "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

   if (_preserved_oop_stack) {

     for (int i = 0; i < _preserved_oop_stack->length(); i++) {

       oop* p = _preserved_oop_stack->adr_at(i);

       adjust_pointer(p);

     }

   }

 }

 void MarkSweep::restore_marks() {

   assert(_preserved_oop_stack == NULL ||

          _preserved_oop_stack->length() == _preserved_mark_stack->length(),

          "inconsistent preserved oop stacks");

   if (PrintGC && Verbose) {

     gclog_or_tty->print_cr("Restoring %d marks", _preserved_count +

                   (_preserved_oop_stack ? _preserved_oop_stack->length() : 0));

   }

   // restore the marks we saved earlier

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

     _preserved_marks[i].restore();

   }

   // deal with the overflow

   if (_preserved_oop_stack) {

     for (int i = 0; i < _preserved_oop_stack->length(); i++) {

       oop obj       = _preserved_oop_stack->at(i);

       markOop mark  = _preserved_mark_stack->at(i);

       obj->set_mark(mark);

     }

   }

 }

 #ifdef VALIDATE_MARK_SWEEP

 void MarkSweep::track_adjusted_pointer(void* p, bool isroot) {

   if (!ValidateMarkSweep)

     return;

   if (!isroot) {

     if (_pointer_tracking) {

       guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");

       _adjusted_pointers->remove(p);

     }

   } else {

     ptrdiff_t index = _root_refs_stack->find(p);

     if (index != -1) {

       int l = _root_refs_stack->length();

       if (l > 0 && l - 1 != index) {

         void* last = _root_refs_stack->pop();

         assert(last != p, "should be different");

         _root_refs_stack->at_put(index, last);

       } else {

         _root_refs_stack->remove(p);

       }

     }

   }

 }

 void MarkSweep::check_adjust_pointer(void* p) {

   _adjusted_pointers->push(p);

 }

 class AdjusterTracker: public OopClosure {

  public:

   AdjusterTracker() {}

   void do_oop(oop* o)       { MarkSweep::check_adjust_pointer(o); }

   void do_oop(narrowOop* o) { MarkSweep::check_adjust_pointer(o); }

 };

 void MarkSweep::track_interior_pointers(oop obj) {

   if (ValidateMarkSweep) {

     _adjusted_pointers->clear();

     _pointer_tracking = true;

     AdjusterTracker checker;

     obj->oop_iterate(&checker);

   }

 }

 void MarkSweep::check_interior_pointers() {

   if (ValidateMarkSweep) {

     _pointer_tracking = false;

     guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");

   }

 }

 void MarkSweep::reset_live_oop_tracking(bool at_perm) {

   if (ValidateMarkSweep) {

     guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");

     _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;

   }

 }

 void MarkSweep::register_live_oop(oop p, size_t size) {

   if (ValidateMarkSweep) {

     _live_oops->push(p);

     _live_oops_size->push(size);

     _live_oops_index++;

   }

 }

 void MarkSweep::validate_live_oop(oop p, size_t size) {

   if (ValidateMarkSweep) {

     oop obj = _live_oops->at((int)_live_oops_index);

     guarantee(obj == p, "should be the same object");

     guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");

     _live_oops_index++;

   }

 }

 void MarkSweep::live_oop_moved_to(HeapWord* q, size_t size,

                                   HeapWord* compaction_top) {

   assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),

          "should be moved to forwarded location");

   if (ValidateMarkSweep) {

     MarkSweep::validate_live_oop(oop(q), size);

     _live_oops_moved_to->push(oop(compaction_top));

   }

   if (RecordMarkSweepCompaction) {

     _cur_gc_live_oops->push(q);

     _cur_gc_live_oops_moved_to->push(compaction_top);

     _cur_gc_live_oops_size->push(size);

   }

 }

 void MarkSweep::compaction_complete() {

   if (RecordMarkSweepCompaction) {

     GrowableArray<HeapWord*>* _tmp_live_oops          = _cur_gc_live_oops;

     GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;

     GrowableArray<size_t>   * _tmp_live_oops_size     = _cur_gc_live_oops_size;

     _cur_gc_live_oops           = _last_gc_live_oops;

     _cur_gc_live_oops_moved_to  = _last_gc_live_oops_moved_to;

     _cur_gc_live_oops_size      = _last_gc_live_oops_size;

     _last_gc_live_oops          = _tmp_live_oops;

     _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;

     _last_gc_live_oops_size     = _tmp_live_oops_size;

   }

 }

 void MarkSweep::print_new_location_of_heap_address(HeapWord* q) {

   if (!RecordMarkSweepCompaction) {

     tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");

     return;

   }

   if (_last_gc_live_oops == NULL) {

     tty->print_cr("No compaction information gathered yet");

     return;

   }

   for (int i = 0; i < _last_gc_live_oops->length(); i++) {

     HeapWord* old_oop = _last_gc_live_oops->at(i);

     size_t    sz      = _last_gc_live_oops_size->at(i);

     if (old_oop <= q && q < (old_oop + sz)) {

       HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);

       size_t offset = (q - old_oop);

       tty->print_cr("Address " PTR_FORMAT, q);

       tty->print_cr(" Was in oop " PTR_FORMAT ", size " SIZE_FORMAT ", at offset " SIZE_FORMAT, old_oop, sz, offset);

       tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);

       return;

     }

   }

   tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);

 }

 #endif //VALIDATE_MARK_SWEEP

 MarkSweep::IsAliveClosure   MarkSweep::is_alive;

 void MarkSweep::IsAliveClosure::do_object(oop p)   { ShouldNotReachHere(); }

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

 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() { /* empty */ }

 #ifndef PRODUCT

 void MarkSweep::trace(const char* msg) {

   if (TraceMarkSweep)

     gclog_or_tty->print("%s", msg);

 }

 #endif