1 /*
   2  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "classfile/javaClasses.hpp"
  27 #include "classfile/systemDictionary.hpp"
  28 #include "gc_implementation/shared/markSweep.inline.hpp"
  29 #include "gc_interface/collectedHeap.hpp"
  30 #include "gc_interface/collectedHeap.inline.hpp"
  31 #include "memory/genCollectedHeap.hpp"
  32 #include "memory/genOopClosures.inline.hpp"
  33 #include "oops/instanceRefKlass.hpp"
  34 #include "oops/oop.inline.hpp"
  35 #include "utilities/preserveException.hpp"
  36 #include "utilities/macros.hpp"
  37 #if INCLUDE_ALL_GCS
  38 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
  39 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
  40 #include "gc_implementation/g1/g1RemSet.inline.hpp"
  41 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
  42 #include "gc_implementation/parNew/parOopClosures.inline.hpp"
  43 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
  44 #include "gc_implementation/parallelScavenge/psScavenge.inline.hpp"

  45 #include "oops/oop.pcgc.inline.hpp"
  46 #endif // INCLUDE_ALL_GCS
  47 
  48 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
  49 
  50 template <class T>
  51 void specialized_oop_follow_contents(InstanceRefKlass* ref, oop obj) {
  52   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
  53   T heap_oop = oopDesc::load_heap_oop(referent_addr);
  54   debug_only(
  55     if(TraceReferenceGC && PrintGCDetails) {
  56       gclog_or_tty->print_cr("InstanceRefKlass::oop_follow_contents " INTPTR_FORMAT, (void *)obj);
  57     }
  58   )
  59   if (!oopDesc::is_null(heap_oop)) {
  60     oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);
  61     if (!referent->is_gc_marked() &&
  62         MarkSweep::ref_processor()->discover_reference(obj, ref->reference_type())) {
  63       // reference was discovered, referent will be traversed later
  64       ref->InstanceKlass::oop_follow_contents(obj);
  65       debug_only(
  66         if(TraceReferenceGC && PrintGCDetails) {
  67           gclog_or_tty->print_cr("       Non NULL enqueued " INTPTR_FORMAT, (void *)obj);
  68         }
  69       )
  70       return;
  71     } else {
  72       // treat referent as normal oop
  73       debug_only(
  74         if(TraceReferenceGC && PrintGCDetails) {
  75           gclog_or_tty->print_cr("       Non NULL normal " INTPTR_FORMAT, (void *)obj);
  76         }
  77       )
  78       MarkSweep::mark_and_push(referent_addr);
  79     }
  80   }
  81   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
  82   if (ReferenceProcessor::pending_list_uses_discovered_field()) {
  83     // Treat discovered as normal oop, if ref is not "active",
  84     // i.e. if next is non-NULL.
  85     T  next_oop = oopDesc::load_heap_oop(next_addr);
  86     if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
  87       T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
  88       debug_only(
  89         if(TraceReferenceGC && PrintGCDetails) {
  90           gclog_or_tty->print_cr("   Process discovered as normal "
  91                                  INTPTR_FORMAT, discovered_addr);
  92         }
  93       )
  94       MarkSweep::mark_and_push(discovered_addr);
  95     }
  96   } else {
  97 #ifdef ASSERT
  98     // In the case of older JDKs which do not use the discovered
  99     // field for the pending list, an inactive ref (next != NULL)
 100     // must always have a NULL discovered field.
 101     oop next = oopDesc::load_decode_heap_oop(next_addr);
 102     oop discovered = java_lang_ref_Reference::discovered(obj);
 103     assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
 104            err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
 105                    (oopDesc*)obj));
 106 #endif
 107   }
 108   // treat next as normal oop.  next is a link in the reference queue.
 109   debug_only(
 110     if(TraceReferenceGC && PrintGCDetails) {
 111       gclog_or_tty->print_cr("   Process next as normal " INTPTR_FORMAT, next_addr);
 112     }
 113   )
 114   MarkSweep::mark_and_push(next_addr);
 115   ref->InstanceKlass::oop_follow_contents(obj);
 116 }
 117 
 118 void InstanceRefKlass::oop_follow_contents(oop obj) {
 119   if (UseCompressedOops) {
 120     specialized_oop_follow_contents<narrowOop>(this, obj);
 121   } else {
 122     specialized_oop_follow_contents<oop>(this, obj);
 123   }
 124 }
 125 
 126 #if INCLUDE_ALL_GCS
 127 template <class T>
 128 void specialized_oop_follow_contents(InstanceRefKlass* ref,
 129                                      ParCompactionManager* cm,
 130                                      oop obj) {
 131   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
 132   T heap_oop = oopDesc::load_heap_oop(referent_addr);
 133   debug_only(
 134     if(TraceReferenceGC && PrintGCDetails) {
 135       gclog_or_tty->print_cr("InstanceRefKlass::oop_follow_contents " INTPTR_FORMAT, (void *)obj);
 136     }
 137   )
 138   if (!oopDesc::is_null(heap_oop)) {
 139     oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);
 140     if (PSParallelCompact::mark_bitmap()->is_unmarked(referent) &&
 141         PSParallelCompact::ref_processor()->
 142           discover_reference(obj, ref->reference_type())) {
 143       // reference already enqueued, referent will be traversed later
 144       ref->InstanceKlass::oop_follow_contents(cm, obj);
 145       debug_only(
 146         if(TraceReferenceGC && PrintGCDetails) {
 147           gclog_or_tty->print_cr("       Non NULL enqueued " INTPTR_FORMAT, (void *)obj);
 148         }
 149       )
 150       return;
 151     } else {
 152       // treat referent as normal oop
 153       debug_only(
 154         if(TraceReferenceGC && PrintGCDetails) {
 155           gclog_or_tty->print_cr("       Non NULL normal " INTPTR_FORMAT, (void *)obj);
 156         }
 157       )
 158       PSParallelCompact::mark_and_push(cm, referent_addr);
 159     }
 160   }
 161   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
 162   if (ReferenceProcessor::pending_list_uses_discovered_field()) {
 163     // Treat discovered as normal oop, if ref is not "active",
 164     // i.e. if next is non-NULL.
 165     T  next_oop = oopDesc::load_heap_oop(next_addr);
 166     if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
 167       T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
 168       debug_only(
 169         if(TraceReferenceGC && PrintGCDetails) {
 170           gclog_or_tty->print_cr("   Process discovered as normal "
 171                                  INTPTR_FORMAT, discovered_addr);
 172         }
 173       )
 174       PSParallelCompact::mark_and_push(cm, discovered_addr);
 175     }
 176   } else {
 177 #ifdef ASSERT
 178     // In the case of older JDKs which do not use the discovered
 179     // field for the pending list, an inactive ref (next != NULL)
 180     // must always have a NULL discovered field.
 181     T next = oopDesc::load_heap_oop(next_addr);
 182     oop discovered = java_lang_ref_Reference::discovered(obj);
 183     assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
 184            err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
 185                    (oopDesc*)obj));
 186 #endif
 187   }
 188   PSParallelCompact::mark_and_push(cm, next_addr);
 189   ref->InstanceKlass::oop_follow_contents(cm, obj);
 190 }
 191 
 192 void InstanceRefKlass::oop_follow_contents(ParCompactionManager* cm,
 193                                            oop obj) {
 194   if (UseCompressedOops) {
 195     specialized_oop_follow_contents<narrowOop>(this, cm, obj);
 196   } else {
 197     specialized_oop_follow_contents<oop>(this, cm, obj);
 198   }
 199 }
 200 #endif // INCLUDE_ALL_GCS
 201 
 202 #ifdef ASSERT
 203 template <class T> void trace_reference_gc(const char *s, oop obj,
 204                                            T* referent_addr,
 205                                            T* next_addr,
 206                                            T* discovered_addr) {
 207   if(TraceReferenceGC && PrintGCDetails) {
 208     gclog_or_tty->print_cr("%s obj " INTPTR_FORMAT, s, (address)obj);
 209     gclog_or_tty->print_cr("     referent_addr/* " INTPTR_FORMAT " / "
 210          INTPTR_FORMAT, referent_addr,
 211          referent_addr ?
 212            (address)oopDesc::load_decode_heap_oop(referent_addr) : NULL);
 213     gclog_or_tty->print_cr("     next_addr/* " INTPTR_FORMAT " / "
 214          INTPTR_FORMAT, next_addr,
 215          next_addr ? (address)oopDesc::load_decode_heap_oop(next_addr) : NULL);
 216     gclog_or_tty->print_cr("     discovered_addr/* " INTPTR_FORMAT " / "
 217          INTPTR_FORMAT, discovered_addr,
 218          discovered_addr ?
 219            (address)oopDesc::load_decode_heap_oop(discovered_addr) : NULL);
 220   }
 221 }
 222 #endif
 223 
 224 template <class T> void specialized_oop_adjust_pointers(InstanceRefKlass *ref, oop obj) {
 225   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
 226   MarkSweep::adjust_pointer(referent_addr);
 227   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
 228   MarkSweep::adjust_pointer(next_addr);
 229   T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
 230   MarkSweep::adjust_pointer(discovered_addr);
 231   debug_only(trace_reference_gc("InstanceRefKlass::oop_adjust_pointers", obj,
 232                                 referent_addr, next_addr, discovered_addr);)
 233 }
 234 
 235 int InstanceRefKlass::oop_adjust_pointers(oop obj) {
 236   int size = size_helper();
 237   InstanceKlass::oop_adjust_pointers(obj);
 238 
 239   if (UseCompressedOops) {
 240     specialized_oop_adjust_pointers<narrowOop>(this, obj);
 241   } else {
 242     specialized_oop_adjust_pointers<oop>(this, obj);
 243   }
 244   return size;
 245 }
 246 
 247 #define InstanceRefKlass_SPECIALIZED_OOP_ITERATE(T, nv_suffix, contains)        \
 248   T* disc_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);             \
 249   if (closure->apply_to_weak_ref_discovered_field()) {                          \
 250     closure->do_oop##nv_suffix(disc_addr);                                      \
 251   }                                                                             \
 252                                                                                 \
 253   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);           \
 254   T heap_oop = oopDesc::load_heap_oop(referent_addr);                           \
 255   ReferenceProcessor* rp = closure->_ref_processor;                             \
 256   if (!oopDesc::is_null(heap_oop)) {                                            \
 257     oop referent = oopDesc::decode_heap_oop_not_null(heap_oop);                 \
 258     if (!referent->is_gc_marked() && (rp != NULL) &&                            \
 259         rp->discover_reference(obj, reference_type())) {                        \
 260       return size;                                                              \
 261     } else if (contains(referent_addr)) {                                       \
 262       /* treat referent as normal oop */                                        \
 263       SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::irk);\
 264       closure->do_oop##nv_suffix(referent_addr);                                \
 265     }                                                                           \
 266   }                                                                             \
 267   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);                   \
 268   if (ReferenceProcessor::pending_list_uses_discovered_field()) {               \
 269     T next_oop  = oopDesc::load_heap_oop(next_addr);                            \
 270     /* Treat discovered as normal oop, if ref is not "active" (next non-NULL) */\
 271     if (!oopDesc::is_null(next_oop) && contains(disc_addr)) {                   \
 272         /* i.e. ref is not "active" */                                          \
 273       debug_only(                                                               \
 274         if(TraceReferenceGC && PrintGCDetails) {                                \
 275           gclog_or_tty->print_cr("   Process discovered as normal "             \
 276                                  INTPTR_FORMAT, disc_addr);                     \
 277         }                                                                       \
 278       )                                                                         \
 279       SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::irk);\
 280       closure->do_oop##nv_suffix(disc_addr);                                    \
 281     }                                                                           \
 282   } else {                                                                      \
 283     /* In the case of older JDKs which do not use the discovered field for  */  \
 284     /* the pending list, an inactive ref (next != NULL) must always have a  */  \
 285     /* NULL discovered field. */                                                \
 286     debug_only(                                                                 \
 287       T next_oop = oopDesc::load_heap_oop(next_addr);                           \
 288       T disc_oop = oopDesc::load_heap_oop(disc_addr);                           \
 289       assert(oopDesc::is_null(next_oop) || oopDesc::is_null(disc_oop),          \
 290            err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL" \
 291                    "discovered field", (oopDesc*)obj));                                   \
 292     )                                                                           \
 293   }                                                                             \
 294   /* treat next as normal oop */                                                \
 295   if (contains(next_addr)) {                                                    \
 296     SpecializationStats::record_do_oop_call##nv_suffix(SpecializationStats::irk); \
 297     closure->do_oop##nv_suffix(next_addr);                                      \
 298   }                                                                             \
 299   return size;                                                                  \
 300 
 301 
 302 template <class T> bool contains(T *t) { return true; }
 303 
 304 // Macro to define InstanceRefKlass::oop_oop_iterate for virtual/nonvirtual for
 305 // all closures.  Macros calling macros above for each oop size.
 306 
 307 #define InstanceRefKlass_OOP_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)        \
 308                                                                                 \
 309 int InstanceRefKlass::                                                          \
 310 oop_oop_iterate##nv_suffix(oop obj, OopClosureType* closure) {                  \
 311   /* Get size before changing pointers */                                       \
 312   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::irk);\
 313                                                                                 \
 314   int size = InstanceKlass::oop_oop_iterate##nv_suffix(obj, closure);           \
 315                                                                                 \
 316   if (UseCompressedOops) {                                                      \
 317     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, contains);   \
 318   } else {                                                                      \
 319     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, contains);         \
 320   }                                                                             \
 321 }
 322 
 323 #if INCLUDE_ALL_GCS
 324 #define InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN(OopClosureType, nv_suffix) \
 325                                                                                 \
 326 int InstanceRefKlass::                                                          \
 327 oop_oop_iterate_backwards##nv_suffix(oop obj, OopClosureType* closure) {        \
 328   /* Get size before changing pointers */                                       \
 329   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::irk);\
 330                                                                                 \
 331   int size = InstanceKlass::oop_oop_iterate_backwards##nv_suffix(obj, closure); \
 332                                                                                 \
 333   if (UseCompressedOops) {                                                      \
 334     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, contains);   \
 335   } else {                                                                      \
 336     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, contains);         \
 337   }                                                                             \
 338 }
 339 #endif // INCLUDE_ALL_GCS
 340 
 341 
 342 #define InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m(OopClosureType, nv_suffix)      \
 343                                                                                 \
 344 int InstanceRefKlass::                                                          \
 345 oop_oop_iterate##nv_suffix##_m(oop obj,                                         \
 346                                OopClosureType* closure,                         \
 347                                MemRegion mr) {                                  \
 348   SpecializationStats::record_iterate_call##nv_suffix(SpecializationStats::irk);\
 349                                                                                 \
 350   int size = InstanceKlass::oop_oop_iterate##nv_suffix##_m(obj, closure, mr);   \
 351   if (UseCompressedOops) {                                                      \
 352     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(narrowOop, nv_suffix, mr.contains); \
 353   } else {                                                                      \
 354     InstanceRefKlass_SPECIALIZED_OOP_ITERATE(oop, nv_suffix, mr.contains);      \
 355   }                                                                             \
 356 }
 357 
 358 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DEFN)
 359 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DEFN)
 360 #if INCLUDE_ALL_GCS
 361 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
 362 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_BACKWARDS_DEFN)
 363 #endif // INCLUDE_ALL_GCS
 364 ALL_OOP_OOP_ITERATE_CLOSURES_1(InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m)
 365 ALL_OOP_OOP_ITERATE_CLOSURES_2(InstanceRefKlass_OOP_OOP_ITERATE_DEFN_m)
 366 
 367 #if INCLUDE_ALL_GCS
 368 template <class T>
 369 void specialized_oop_push_contents(InstanceRefKlass *ref,
 370                                    PSPromotionManager* pm, oop obj) {
 371   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
 372   if (PSScavenge::should_scavenge(referent_addr)) {
 373     ReferenceProcessor* rp = PSScavenge::reference_processor();
 374     if (rp->discover_reference(obj, ref->reference_type())) {
 375       // reference already enqueued, referent and next will be traversed later
 376       ref->InstanceKlass::oop_push_contents(pm, obj);
 377       return;
 378     } else {
 379       // treat referent as normal oop
 380       pm->claim_or_forward_depth(referent_addr);
 381     }
 382   }
 383   // Treat discovered as normal oop, if ref is not "active",
 384   // i.e. if next is non-NULL.
 385   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
 386   if (ReferenceProcessor::pending_list_uses_discovered_field()) {
 387     T  next_oop = oopDesc::load_heap_oop(next_addr);
 388     if (!oopDesc::is_null(next_oop)) { // i.e. ref is not "active"
 389       T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
 390       debug_only(
 391         if(TraceReferenceGC && PrintGCDetails) {
 392           gclog_or_tty->print_cr("   Process discovered as normal "
 393                                  INTPTR_FORMAT, discovered_addr);
 394         }
 395       )
 396       if (PSScavenge::should_scavenge(discovered_addr)) {
 397         pm->claim_or_forward_depth(discovered_addr);
 398       }
 399     }
 400   } else {
 401 #ifdef ASSERT
 402     // In the case of older JDKs which do not use the discovered
 403     // field for the pending list, an inactive ref (next != NULL)
 404     // must always have a NULL discovered field.
 405     oop next = oopDesc::load_decode_heap_oop(next_addr);
 406     oop discovered = java_lang_ref_Reference::discovered(obj);
 407     assert(oopDesc::is_null(next) || oopDesc::is_null(discovered),
 408            err_msg("Found an inactive reference " PTR_FORMAT " with a non-NULL discovered field",
 409                    (oopDesc*)obj));
 410 #endif
 411   }
 412 
 413   // Treat next as normal oop;  next is a link in the reference queue.
 414   if (PSScavenge::should_scavenge(next_addr)) {
 415     pm->claim_or_forward_depth(next_addr);
 416   }
 417   ref->InstanceKlass::oop_push_contents(pm, obj);
 418 }
 419 
 420 void InstanceRefKlass::oop_push_contents(PSPromotionManager* pm, oop obj) {
 421   if (UseCompressedOops) {
 422     specialized_oop_push_contents<narrowOop>(this, pm, obj);
 423   } else {
 424     specialized_oop_push_contents<oop>(this, pm, obj);
 425   }
 426 }
 427 
 428 template <class T>
 429 void specialized_oop_update_pointers(InstanceRefKlass *ref,
 430                                     ParCompactionManager* cm, oop obj) {
 431   T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
 432   PSParallelCompact::adjust_pointer(referent_addr);
 433   T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
 434   PSParallelCompact::adjust_pointer(next_addr);
 435   T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
 436   PSParallelCompact::adjust_pointer(discovered_addr);
 437   debug_only(trace_reference_gc("InstanceRefKlass::oop_update_ptrs", obj,
 438                                 referent_addr, next_addr, discovered_addr);)
 439 }
 440 
 441 int InstanceRefKlass::oop_update_pointers(ParCompactionManager* cm, oop obj) {
 442   InstanceKlass::oop_update_pointers(cm, obj);
 443   if (UseCompressedOops) {
 444     specialized_oop_update_pointers<narrowOop>(this, cm, obj);
 445   } else {
 446     specialized_oop_update_pointers<oop>(this, cm, obj);
 447   }
 448   return size_helper();
 449 }
 450 #endif // INCLUDE_ALL_GCS
 451 
 452 void InstanceRefKlass::update_nonstatic_oop_maps(Klass* k) {
 453   // Clear the nonstatic oop-map entries corresponding to referent
 454   // and nextPending field.  They are treated specially by the
 455   // garbage collector.
 456   // The discovered field is used only by the garbage collector
 457   // and is also treated specially.
 458   InstanceKlass* ik = InstanceKlass::cast(k);
 459 
 460   // Check that we have the right class
 461   debug_only(static bool first_time = true);
 462   assert(k == SystemDictionary::Reference_klass() && first_time,
 463          "Invalid update of maps");
 464   debug_only(first_time = false);
 465   assert(ik->nonstatic_oop_map_count() == 1, "just checking");
 466 
 467   OopMapBlock* map = ik->start_of_nonstatic_oop_maps();
 468 
 469   // Check that the current map is (2,4) - currently points at field with
 470   // offset 2 (words) and has 4 map entries.
 471   debug_only(int offset = java_lang_ref_Reference::referent_offset);
 472   debug_only(unsigned int count = ((java_lang_ref_Reference::discovered_offset -
 473     java_lang_ref_Reference::referent_offset)/heapOopSize) + 1);
 474 
 475   if (UseSharedSpaces) {
 476     assert(map->offset() == java_lang_ref_Reference::queue_offset &&
 477            map->count() == 1, "just checking");
 478   } else {
 479     assert(map->offset() == offset && map->count() == count,
 480            "just checking");
 481 
 482     // Update map to (3,1) - point to offset of 3 (words) with 1 map entry.
 483     map->set_offset(java_lang_ref_Reference::queue_offset);
 484     map->set_count(1);
 485   }
 486 }
 487 
 488 
 489 // Verification
 490 
 491 void InstanceRefKlass::oop_verify_on(oop obj, outputStream* st) {
 492   InstanceKlass::oop_verify_on(obj, st);
 493   // Verify referent field
 494   oop referent = java_lang_ref_Reference::referent(obj);
 495 
 496   // We should make this general to all heaps
 497   GenCollectedHeap* gch = NULL;
 498   if (Universe::heap()->kind() == CollectedHeap::GenCollectedHeap)
 499     gch = GenCollectedHeap::heap();
 500 
 501   if (referent != NULL) {
 502     guarantee(referent->is_oop(), "referent field heap failed");
 503   }
 504   // Verify next field
 505   oop next = java_lang_ref_Reference::next(obj);
 506   if (next != NULL) {
 507     guarantee(next->is_oop(), "next field verify failed");
 508     guarantee(next->is_instanceRef(), "next field verify failed");
 509   }
 510 }
 511 
 512 bool InstanceRefKlass::owns_pending_list_lock(JavaThread* thread) {
 513   if (java_lang_ref_Reference::pending_list_lock() == NULL) return false;
 514   Handle h_lock(thread, java_lang_ref_Reference::pending_list_lock());
 515   return ObjectSynchronizer::current_thread_holds_lock(thread, h_lock);
 516 }
 517 
 518 void InstanceRefKlass::acquire_pending_list_lock(BasicLock *pending_list_basic_lock) {
 519   // we may enter this with pending exception set
 520   PRESERVE_EXCEPTION_MARK;  // exceptions are never thrown, needed for TRAPS argument
 521 
 522   // Create a HandleMark in case we retry a GC multiple times.
 523   // Each time we attempt the GC, we allocate the handle below
 524   // to hold the pending list lock. We want to free this handle.
 525   HandleMark hm;
 526 
 527   Handle h_lock(THREAD, java_lang_ref_Reference::pending_list_lock());
 528   ObjectSynchronizer::fast_enter(h_lock, pending_list_basic_lock, false, THREAD);
 529   assert(ObjectSynchronizer::current_thread_holds_lock(
 530            JavaThread::current(), h_lock),
 531          "Locking should have succeeded");
 532   if (HAS_PENDING_EXCEPTION) CLEAR_PENDING_EXCEPTION;
 533 }
 534 
 535 void InstanceRefKlass::release_and_notify_pending_list_lock(
 536   BasicLock *pending_list_basic_lock) {
 537   // we may enter this with pending exception set
 538   PRESERVE_EXCEPTION_MARK;  // exceptions are never thrown, needed for TRAPS argument
 539 
 540   // Create a HandleMark in case we retry a GC multiple times.
 541   // Each time we attempt the GC, we allocate the handle below
 542   // to hold the pending list lock. We want to free this handle.
 543   HandleMark hm;
 544 
 545   Handle h_lock(THREAD, java_lang_ref_Reference::pending_list_lock());
 546   assert(ObjectSynchronizer::current_thread_holds_lock(
 547            JavaThread::current(), h_lock),
 548          "Lock should be held");
 549   // Notify waiters on pending lists lock if there is any reference.
 550   if (java_lang_ref_Reference::pending_list() != NULL) {
 551     ObjectSynchronizer::notifyall(h_lock, THREAD);
 552   }
 553   ObjectSynchronizer::fast_exit(h_lock(), pending_list_basic_lock, THREAD);
 554   if (HAS_PENDING_EXCEPTION) CLEAR_PENDING_EXCEPTION;
 555 }
--- EOF ---