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 /*

  * Copyright (c) 1998, 2010, 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/oopRecorder.hpp"

 #include "memory/allocation.inline.hpp"

 #include "oops/oop.inline.hpp"

 #ifdef ASSERT

 int OopRecorder::_find_index_calls = 0;

 int OopRecorder::_hit_indexes      = 0;

 int OopRecorder::_missed_indexes   = 0;

 #endif //ASSERT

 OopRecorder::OopRecorder(Arena* arena) {

   _handles  = NULL;

   _indexes  = NULL;

   _arena    = arena;

   _complete = false;

 }

 OopRecorder::IndexCache::IndexCache() {

   assert(first_index > 0, "initial zero state of cache must be invalid index");

   Copy::zero_to_bytes(&_cache[0], sizeof(_cache));

 }

 int OopRecorder::oop_size() {

   _complete = true;

   if (_handles == NULL)  return 0;

   return _handles->length() * sizeof(oop);

 }

 void OopRecorder::copy_to(nmethod* nm) {

   assert(_complete, "must be frozen");

   maybe_initialize();  // get non-null handles, even if we have no oops

   nm->copy_oops(_handles);

 }

 void OopRecorder::maybe_initialize() {

   if (_handles == NULL) {

     if (_arena != NULL) {

       _handles  = new(_arena) GrowableArray<jobject>(_arena, 10, 0, 0);

       _no_finds = new(_arena) GrowableArray<int>(    _arena, 10, 0, 0);

     } else {

       _handles  = new GrowableArray<jobject>(10, 0, 0);

       _no_finds = new GrowableArray<int>(    10, 0, 0);

     }

   }

 }

 jobject OopRecorder::handle_at(int index) {

   // there is always a NULL virtually present as first object

   if (index == null_index)  return NULL;

   return _handles->at(index - first_index);

 }

 // Local definition.  Used only in this module.

 inline bool OopRecorder::is_real_jobject(jobject h) {

   return h != NULL && h != (jobject)Universe::non_oop_word();

 }

 int OopRecorder::add_handle(jobject h, bool make_findable) {

   assert(!_complete, "cannot allocate more elements after size query");

   maybe_initialize();

   // indexing uses 1 as an origin--0 means null

   int index = _handles->length() + first_index;

   _handles->append(h);

   // Support correct operation of find_index().

   assert(!(make_findable && !is_real_jobject(h)), "nulls are not findable");

   if (make_findable) {

     // This index may be returned from find_index().

     if (_indexes != NULL) {

       int* cloc = _indexes->cache_location(h);

       _indexes->set_cache_location_index(cloc, index);

     } else if (index == index_cache_threshold && _arena != NULL) {

       _indexes = new(_arena) IndexCache();

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

         // Load the cache with pre-existing elements.

         int index0 = i + first_index;

         if (_no_finds->contains(index0))  continue;

         int* cloc = _indexes->cache_location(_handles->at(i));

         _indexes->set_cache_location_index(cloc, index0);

       }

     }

   } else if (is_real_jobject(h)) {

     // Remember that this index is not to be returned from find_index().

     // This case is rare, because most or all uses of allocate_index pass

     // a jobject argument of NULL or Universe::non_oop_word.

     // Thus, the expected length of _no_finds is zero.

     _no_finds->append(index);

   }

   return index;

 }

 int OopRecorder::maybe_find_index(jobject h) {

   debug_only(_find_index_calls++);

   assert(!_complete, "cannot allocate more elements after size query");

   maybe_initialize();

   if (h == NULL)  return null_index;

   assert(is_real_jobject(h), "must be valid jobject");

   int* cloc = (_indexes == NULL)? NULL: _indexes->cache_location(h);

   if (cloc != NULL) {

     int cindex = _indexes->cache_location_index(cloc);

     if (cindex == 0) {

       return -1;   // We know this handle is completely new.

     }

     if (cindex >= first_index && _handles->at(cindex - first_index) == h) {

       debug_only(_hit_indexes++);

       return cindex;

     }

     if (!_indexes->cache_location_collision(cloc)) {

       return -1;   // We know the current cache occupant is unique to that cloc.

     }

   }

   // Not found in cache, due to a cache collision.  (Or, no cache at all.)

   // Do a linear search, most recent to oldest.

   for (int i = _handles->length() - 1; i >= 0; i--) {

     if (_handles->at(i) == h) {

       int findex = i + first_index;

       if (_no_finds->contains(findex))  continue;  // oops; skip this one

       if (cloc != NULL) {

         _indexes->set_cache_location_index(cloc, findex);

       }

       debug_only(_missed_indexes++);

       return findex;

     }

   }

   return -1;

 }