src/share/vm/memory/space.hpp

Tue, 24 Dec 2013 11:48:39 -0800

author
mikael
date
Tue, 24 Dec 2013 11:48:39 -0800
changeset 6198
55fb97c4c58d
parent 5119
12f651e29f6b
child 6503
a9becfeecd1b
permissions
-rw-r--r--

8029233: Update copyright year to match last edit in jdk8 hotspot repository for 2013
Summary: Copyright year updated for files modified during 2013
Reviewed-by: twisti, iveresov

     1 /*
     2  * Copyright (c) 1997, 2013, 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  */
    25 #ifndef SHARE_VM_MEMORY_SPACE_HPP
    26 #define SHARE_VM_MEMORY_SPACE_HPP
    28 #include "memory/allocation.hpp"
    29 #include "memory/blockOffsetTable.hpp"
    30 #include "memory/cardTableModRefBS.hpp"
    31 #include "memory/iterator.hpp"
    32 #include "memory/memRegion.hpp"
    33 #include "memory/watermark.hpp"
    34 #include "oops/markOop.hpp"
    35 #include "runtime/mutexLocker.hpp"
    36 #include "runtime/prefetch.hpp"
    37 #include "utilities/macros.hpp"
    38 #include "utilities/workgroup.hpp"
    39 #ifdef TARGET_OS_FAMILY_linux
    40 # include "os_linux.inline.hpp"
    41 #endif
    42 #ifdef TARGET_OS_FAMILY_solaris
    43 # include "os_solaris.inline.hpp"
    44 #endif
    45 #ifdef TARGET_OS_FAMILY_windows
    46 # include "os_windows.inline.hpp"
    47 #endif
    48 #ifdef TARGET_OS_FAMILY_bsd
    49 # include "os_bsd.inline.hpp"
    50 #endif
    52 // A space is an abstraction for the "storage units" backing
    53 // up the generation abstraction. It includes specific
    54 // implementations for keeping track of free and used space,
    55 // for iterating over objects and free blocks, etc.
    57 // Here's the Space hierarchy:
    58 //
    59 // - Space               -- an asbtract base class describing a heap area
    60 //   - CompactibleSpace  -- a space supporting compaction
    61 //     - CompactibleFreeListSpace -- (used for CMS generation)
    62 //     - ContiguousSpace -- a compactible space in which all free space
    63 //                          is contiguous
    64 //       - EdenSpace     -- contiguous space used as nursery
    65 //         - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation
    66 //       - OffsetTableContigSpace -- contiguous space with a block offset array
    67 //                          that allows "fast" block_start calls
    68 //         - TenuredSpace -- (used for TenuredGeneration)
    70 // Forward decls.
    71 class Space;
    72 class BlockOffsetArray;
    73 class BlockOffsetArrayContigSpace;
    74 class Generation;
    75 class CompactibleSpace;
    76 class BlockOffsetTable;
    77 class GenRemSet;
    78 class CardTableRS;
    79 class DirtyCardToOopClosure;
    81 // An oop closure that is circumscribed by a filtering memory region.
    82 class SpaceMemRegionOopsIterClosure: public ExtendedOopClosure {
    83  private:
    84   ExtendedOopClosure* _cl;
    85   MemRegion   _mr;
    86  protected:
    87   template <class T> void do_oop_work(T* p) {
    88     if (_mr.contains(p)) {
    89       _cl->do_oop(p);
    90     }
    91   }
    92  public:
    93   SpaceMemRegionOopsIterClosure(ExtendedOopClosure* cl, MemRegion mr):
    94     _cl(cl), _mr(mr) {}
    95   virtual void do_oop(oop* p);
    96   virtual void do_oop(narrowOop* p);
    97   virtual bool do_metadata() {
    98     // _cl is of type ExtendedOopClosure instead of OopClosure, so that we can check this.
    99     assert(!_cl->do_metadata(), "I've checked all call paths, this shouldn't happen.");
   100     return false;
   101   }
   102   virtual void do_klass(Klass* k)                         { ShouldNotReachHere(); }
   103   virtual void do_class_loader_data(ClassLoaderData* cld) { ShouldNotReachHere(); }
   104 };
   106 // A Space describes a heap area. Class Space is an abstract
   107 // base class.
   108 //
   109 // Space supports allocation, size computation and GC support is provided.
   110 //
   111 // Invariant: bottom() and end() are on page_size boundaries and
   112 // bottom() <= top() <= end()
   113 // top() is inclusive and end() is exclusive.
   115 class Space: public CHeapObj<mtGC> {
   116   friend class VMStructs;
   117  protected:
   118   HeapWord* _bottom;
   119   HeapWord* _end;
   121   // Used in support of save_marks()
   122   HeapWord* _saved_mark_word;
   124   MemRegionClosure* _preconsumptionDirtyCardClosure;
   126   // A sequential tasks done structure. This supports
   127   // parallel GC, where we have threads dynamically
   128   // claiming sub-tasks from a larger parallel task.
   129   SequentialSubTasksDone _par_seq_tasks;
   131   Space():
   132     _bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { }
   134  public:
   135   // Accessors
   136   HeapWord* bottom() const         { return _bottom; }
   137   HeapWord* end() const            { return _end;    }
   138   virtual void set_bottom(HeapWord* value) { _bottom = value; }
   139   virtual void set_end(HeapWord* value)    { _end = value; }
   141   virtual HeapWord* saved_mark_word() const  { return _saved_mark_word; }
   143   void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; }
   145   MemRegionClosure* preconsumptionDirtyCardClosure() const {
   146     return _preconsumptionDirtyCardClosure;
   147   }
   148   void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) {
   149     _preconsumptionDirtyCardClosure = cl;
   150   }
   152   // Returns a subregion of the space containing all the objects in
   153   // the space.
   154   virtual MemRegion used_region() const { return MemRegion(bottom(), end()); }
   156   // Returns a region that is guaranteed to contain (at least) all objects
   157   // allocated at the time of the last call to "save_marks".  If the space
   158   // initializes its DirtyCardToOopClosure's specifying the "contig" option
   159   // (that is, if the space is contiguous), then this region must contain only
   160   // such objects: the memregion will be from the bottom of the region to the
   161   // saved mark.  Otherwise, the "obj_allocated_since_save_marks" method of
   162   // the space must distiguish between objects in the region allocated before
   163   // and after the call to save marks.
   164   virtual MemRegion used_region_at_save_marks() const {
   165     return MemRegion(bottom(), saved_mark_word());
   166   }
   168   // Initialization.
   169   // "initialize" should be called once on a space, before it is used for
   170   // any purpose.  The "mr" arguments gives the bounds of the space, and
   171   // the "clear_space" argument should be true unless the memory in "mr" is
   172   // known to be zeroed.
   173   virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
   175   // The "clear" method must be called on a region that may have
   176   // had allocation performed in it, but is now to be considered empty.
   177   virtual void clear(bool mangle_space);
   179   // For detecting GC bugs.  Should only be called at GC boundaries, since
   180   // some unused space may be used as scratch space during GC's.
   181   // Default implementation does nothing. We also call this when expanding
   182   // a space to satisfy an allocation request. See bug #4668531
   183   virtual void mangle_unused_area() {}
   184   virtual void mangle_unused_area_complete() {}
   185   virtual void mangle_region(MemRegion mr) {}
   187   // Testers
   188   bool is_empty() const              { return used() == 0; }
   189   bool not_empty() const             { return used() > 0; }
   191   // Returns true iff the given the space contains the
   192   // given address as part of an allocated object. For
   193   // ceratin kinds of spaces, this might be a potentially
   194   // expensive operation. To prevent performance problems
   195   // on account of its inadvertent use in product jvm's,
   196   // we restrict its use to assertion checks only.
   197   virtual bool is_in(const void* p) const = 0;
   199   // Returns true iff the given reserved memory of the space contains the
   200   // given address.
   201   bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; }
   203   // Returns true iff the given block is not allocated.
   204   virtual bool is_free_block(const HeapWord* p) const = 0;
   206   // Test whether p is double-aligned
   207   static bool is_aligned(void* p) {
   208     return ((intptr_t)p & (sizeof(double)-1)) == 0;
   209   }
   211   // Size computations.  Sizes are in bytes.
   212   size_t capacity()     const { return byte_size(bottom(), end()); }
   213   virtual size_t used() const = 0;
   214   virtual size_t free() const = 0;
   216   // Iterate over all the ref-containing fields of all objects in the
   217   // space, calling "cl.do_oop" on each.  Fields in objects allocated by
   218   // applications of the closure are not included in the iteration.
   219   virtual void oop_iterate(ExtendedOopClosure* cl);
   221   // Same as above, restricted to the intersection of a memory region and
   222   // the space.  Fields in objects allocated by applications of the closure
   223   // are not included in the iteration.
   224   virtual void oop_iterate(MemRegion mr, ExtendedOopClosure* cl) = 0;
   226   // Iterate over all objects in the space, calling "cl.do_object" on
   227   // each.  Objects allocated by applications of the closure are not
   228   // included in the iteration.
   229   virtual void object_iterate(ObjectClosure* blk) = 0;
   230   // Similar to object_iterate() except only iterates over
   231   // objects whose internal references point to objects in the space.
   232   virtual void safe_object_iterate(ObjectClosure* blk) = 0;
   234   // Iterate over all objects that intersect with mr, calling "cl->do_object"
   235   // on each.  There is an exception to this: if this closure has already
   236   // been invoked on an object, it may skip such objects in some cases.  This is
   237   // Most likely to happen in an "upwards" (ascending address) iteration of
   238   // MemRegions.
   239   virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
   241   // Iterate over as many initialized objects in the space as possible,
   242   // calling "cl.do_object_careful" on each. Return NULL if all objects
   243   // in the space (at the start of the iteration) were iterated over.
   244   // Return an address indicating the extent of the iteration in the
   245   // event that the iteration had to return because of finding an
   246   // uninitialized object in the space, or if the closure "cl"
   247   // signalled early termination.
   248   virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
   249   virtual HeapWord* object_iterate_careful_m(MemRegion mr,
   250                                              ObjectClosureCareful* cl);
   252   // Create and return a new dirty card to oop closure. Can be
   253   // overriden to return the appropriate type of closure
   254   // depending on the type of space in which the closure will
   255   // operate. ResourceArea allocated.
   256   virtual DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl,
   257                                              CardTableModRefBS::PrecisionStyle precision,
   258                                              HeapWord* boundary = NULL);
   260   // If "p" is in the space, returns the address of the start of the
   261   // "block" that contains "p".  We say "block" instead of "object" since
   262   // some heaps may not pack objects densely; a chunk may either be an
   263   // object or a non-object.  If "p" is not in the space, return NULL.
   264   virtual HeapWord* block_start_const(const void* p) const = 0;
   266   // The non-const version may have benevolent side effects on the data
   267   // structure supporting these calls, possibly speeding up future calls.
   268   // The default implementation, however, is simply to call the const
   269   // version.
   270   inline virtual HeapWord* block_start(const void* p);
   272   // Requires "addr" to be the start of a chunk, and returns its size.
   273   // "addr + size" is required to be the start of a new chunk, or the end
   274   // of the active area of the heap.
   275   virtual size_t block_size(const HeapWord* addr) const = 0;
   277   // Requires "addr" to be the start of a block, and returns "TRUE" iff
   278   // the block is an object.
   279   virtual bool block_is_obj(const HeapWord* addr) const = 0;
   281   // Requires "addr" to be the start of a block, and returns "TRUE" iff
   282   // the block is an object and the object is alive.
   283   virtual bool obj_is_alive(const HeapWord* addr) const;
   285   // Allocation (return NULL if full).  Assumes the caller has established
   286   // mutually exclusive access to the space.
   287   virtual HeapWord* allocate(size_t word_size) = 0;
   289   // Allocation (return NULL if full).  Enforces mutual exclusion internally.
   290   virtual HeapWord* par_allocate(size_t word_size) = 0;
   292   // Returns true if this object has been allocated since a
   293   // generation's "save_marks" call.
   294   virtual bool obj_allocated_since_save_marks(const oop obj) const = 0;
   296   // Mark-sweep-compact support: all spaces can update pointers to objects
   297   // moving as a part of compaction.
   298   virtual void adjust_pointers();
   300   // PrintHeapAtGC support
   301   virtual void print() const;
   302   virtual void print_on(outputStream* st) const;
   303   virtual void print_short() const;
   304   virtual void print_short_on(outputStream* st) const;
   307   // Accessor for parallel sequential tasks.
   308   SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; }
   310   // IF "this" is a ContiguousSpace, return it, else return NULL.
   311   virtual ContiguousSpace* toContiguousSpace() {
   312     return NULL;
   313   }
   315   // Debugging
   316   virtual void verify() const = 0;
   317 };
   319 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an
   320 // OopClosure to (the addresses of) all the ref-containing fields that could
   321 // be modified by virtue of the given MemRegion being dirty. (Note that
   322 // because of the imprecise nature of the write barrier, this may iterate
   323 // over oops beyond the region.)
   324 // This base type for dirty card to oop closures handles memory regions
   325 // in non-contiguous spaces with no boundaries, and should be sub-classed
   326 // to support other space types. See ContiguousDCTOC for a sub-class
   327 // that works with ContiguousSpaces.
   329 class DirtyCardToOopClosure: public MemRegionClosureRO {
   330 protected:
   331   ExtendedOopClosure* _cl;
   332   Space* _sp;
   333   CardTableModRefBS::PrecisionStyle _precision;
   334   HeapWord* _boundary;          // If non-NULL, process only non-NULL oops
   335                                 // pointing below boundary.
   336   HeapWord* _min_done;          // ObjHeadPreciseArray precision requires
   337                                 // a downwards traversal; this is the
   338                                 // lowest location already done (or,
   339                                 // alternatively, the lowest address that
   340                                 // shouldn't be done again.  NULL means infinity.)
   341   NOT_PRODUCT(HeapWord* _last_bottom;)
   342   NOT_PRODUCT(HeapWord* _last_explicit_min_done;)
   344   // Get the actual top of the area on which the closure will
   345   // operate, given where the top is assumed to be (the end of the
   346   // memory region passed to do_MemRegion) and where the object
   347   // at the top is assumed to start. For example, an object may
   348   // start at the top but actually extend past the assumed top,
   349   // in which case the top becomes the end of the object.
   350   virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj);
   352   // Walk the given memory region from bottom to (actual) top
   353   // looking for objects and applying the oop closure (_cl) to
   354   // them. The base implementation of this treats the area as
   355   // blocks, where a block may or may not be an object. Sub-
   356   // classes should override this to provide more accurate
   357   // or possibly more efficient walking.
   358   virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top);
   360 public:
   361   DirtyCardToOopClosure(Space* sp, ExtendedOopClosure* cl,
   362                         CardTableModRefBS::PrecisionStyle precision,
   363                         HeapWord* boundary) :
   364     _sp(sp), _cl(cl), _precision(precision), _boundary(boundary),
   365     _min_done(NULL) {
   366     NOT_PRODUCT(_last_bottom = NULL);
   367     NOT_PRODUCT(_last_explicit_min_done = NULL);
   368   }
   370   void do_MemRegion(MemRegion mr);
   372   void set_min_done(HeapWord* min_done) {
   373     _min_done = min_done;
   374     NOT_PRODUCT(_last_explicit_min_done = _min_done);
   375   }
   376 #ifndef PRODUCT
   377   void set_last_bottom(HeapWord* last_bottom) {
   378     _last_bottom = last_bottom;
   379   }
   380 #endif
   381 };
   383 // A structure to represent a point at which objects are being copied
   384 // during compaction.
   385 class CompactPoint : public StackObj {
   386 public:
   387   Generation* gen;
   388   CompactibleSpace* space;
   389   HeapWord* threshold;
   390   CompactPoint(Generation* _gen, CompactibleSpace* _space,
   391                HeapWord* _threshold) :
   392     gen(_gen), space(_space), threshold(_threshold) {}
   393 };
   396 // A space that supports compaction operations.  This is usually, but not
   397 // necessarily, a space that is normally contiguous.  But, for example, a
   398 // free-list-based space whose normal collection is a mark-sweep without
   399 // compaction could still support compaction in full GC's.
   401 class CompactibleSpace: public Space {
   402   friend class VMStructs;
   403   friend class CompactibleFreeListSpace;
   404 private:
   405   HeapWord* _compaction_top;
   406   CompactibleSpace* _next_compaction_space;
   408 public:
   409   CompactibleSpace() :
   410    _compaction_top(NULL), _next_compaction_space(NULL) {}
   412   virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
   413   virtual void clear(bool mangle_space);
   415   // Used temporarily during a compaction phase to hold the value
   416   // top should have when compaction is complete.
   417   HeapWord* compaction_top() const { return _compaction_top;    }
   419   void set_compaction_top(HeapWord* value) {
   420     assert(value == NULL || (value >= bottom() && value <= end()),
   421       "should point inside space");
   422     _compaction_top = value;
   423   }
   425   // Perform operations on the space needed after a compaction
   426   // has been performed.
   427   virtual void reset_after_compaction() {}
   429   // Returns the next space (in the current generation) to be compacted in
   430   // the global compaction order.  Also is used to select the next
   431   // space into which to compact.
   433   virtual CompactibleSpace* next_compaction_space() const {
   434     return _next_compaction_space;
   435   }
   437   void set_next_compaction_space(CompactibleSpace* csp) {
   438     _next_compaction_space = csp;
   439   }
   441   // MarkSweep support phase2
   443   // Start the process of compaction of the current space: compute
   444   // post-compaction addresses, and insert forwarding pointers.  The fields
   445   // "cp->gen" and "cp->compaction_space" are the generation and space into
   446   // which we are currently compacting.  This call updates "cp" as necessary,
   447   // and leaves the "compaction_top" of the final value of
   448   // "cp->compaction_space" up-to-date.  Offset tables may be updated in
   449   // this phase as if the final copy had occurred; if so, "cp->threshold"
   450   // indicates when the next such action should be taken.
   451   virtual void prepare_for_compaction(CompactPoint* cp);
   452   // MarkSweep support phase3
   453   virtual void adjust_pointers();
   454   // MarkSweep support phase4
   455   virtual void compact();
   457   // The maximum percentage of objects that can be dead in the compacted
   458   // live part of a compacted space ("deadwood" support.)
   459   virtual size_t allowed_dead_ratio() const { return 0; };
   461   // Some contiguous spaces may maintain some data structures that should
   462   // be updated whenever an allocation crosses a boundary.  This function
   463   // returns the first such boundary.
   464   // (The default implementation returns the end of the space, so the
   465   // boundary is never crossed.)
   466   virtual HeapWord* initialize_threshold() { return end(); }
   468   // "q" is an object of the given "size" that should be forwarded;
   469   // "cp" names the generation ("gen") and containing "this" (which must
   470   // also equal "cp->space").  "compact_top" is where in "this" the
   471   // next object should be forwarded to.  If there is room in "this" for
   472   // the object, insert an appropriate forwarding pointer in "q".
   473   // If not, go to the next compaction space (there must
   474   // be one, since compaction must succeed -- we go to the first space of
   475   // the previous generation if necessary, updating "cp"), reset compact_top
   476   // and then forward.  In either case, returns the new value of "compact_top".
   477   // If the forwarding crosses "cp->threshold", invokes the "cross_threhold"
   478   // function of the then-current compaction space, and updates "cp->threshold
   479   // accordingly".
   480   virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp,
   481                     HeapWord* compact_top);
   483   // Return a size with adjusments as required of the space.
   484   virtual size_t adjust_object_size_v(size_t size) const { return size; }
   486 protected:
   487   // Used during compaction.
   488   HeapWord* _first_dead;
   489   HeapWord* _end_of_live;
   491   // Minimum size of a free block.
   492   virtual size_t minimum_free_block_size() const = 0;
   494   // This the function is invoked when an allocation of an object covering
   495   // "start" to "end occurs crosses the threshold; returns the next
   496   // threshold.  (The default implementation does nothing.)
   497   virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) {
   498     return end();
   499   }
   501   // Requires "allowed_deadspace_words > 0", that "q" is the start of a
   502   // free block of the given "word_len", and that "q", were it an object,
   503   // would not move if forwared.  If the size allows, fill the free
   504   // block with an object, to prevent excessive compaction.  Returns "true"
   505   // iff the free region was made deadspace, and modifies
   506   // "allowed_deadspace_words" to reflect the number of available deadspace
   507   // words remaining after this operation.
   508   bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q,
   509                         size_t word_len);
   510 };
   512 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) {            \
   513   /* Compute the new addresses for the live objects and store it in the mark \
   514    * Used by universe::mark_sweep_phase2()                                   \
   515    */                                                                        \
   516   HeapWord* compact_top; /* This is where we are currently compacting to. */ \
   517                                                                              \
   518   /* We're sure to be here before any objects are compacted into this        \
   519    * space, so this is a good time to initialize this:                       \
   520    */                                                                        \
   521   set_compaction_top(bottom());                                              \
   522                                                                              \
   523   if (cp->space == NULL) {                                                   \
   524     assert(cp->gen != NULL, "need a generation");                            \
   525     assert(cp->threshold == NULL, "just checking");                          \
   526     assert(cp->gen->first_compaction_space() == this, "just checking");      \
   527     cp->space = cp->gen->first_compaction_space();                           \
   528     compact_top = cp->space->bottom();                                       \
   529     cp->space->set_compaction_top(compact_top);                              \
   530     cp->threshold = cp->space->initialize_threshold();                       \
   531   } else {                                                                   \
   532     compact_top = cp->space->compaction_top();                               \
   533   }                                                                          \
   534                                                                              \
   535   /* We allow some amount of garbage towards the bottom of the space, so     \
   536    * we don't start compacting before there is a significant gain to be made.\
   537    * Occasionally, we want to ensure a full compaction, which is determined  \
   538    * by the MarkSweepAlwaysCompactCount parameter.                           \
   539    */                                                                        \
   540   uint invocations = MarkSweep::total_invocations();                         \
   541   bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0);       \
   542                                                                              \
   543   size_t allowed_deadspace = 0;                                              \
   544   if (skip_dead) {                                                           \
   545     const size_t ratio = allowed_dead_ratio();                               \
   546     allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize;           \
   547   }                                                                          \
   548                                                                              \
   549   HeapWord* q = bottom();                                                    \
   550   HeapWord* t = scan_limit();                                                \
   551                                                                              \
   552   HeapWord*  end_of_live= q;    /* One byte beyond the last byte of the last \
   553                                    live object. */                           \
   554   HeapWord*  first_dead = end();/* The first dead object. */                 \
   555   LiveRange* liveRange  = NULL; /* The current live range, recorded in the   \
   556                                    first header of preceding free area. */   \
   557   _first_dead = first_dead;                                                  \
   558                                                                              \
   559   const intx interval = PrefetchScanIntervalInBytes;                         \
   560                                                                              \
   561   while (q < t) {                                                            \
   562     assert(!block_is_obj(q) ||                                               \
   563            oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() ||   \
   564            oop(q)->mark()->has_bias_pattern(),                               \
   565            "these are the only valid states during a mark sweep");           \
   566     if (block_is_obj(q) && oop(q)->is_gc_marked()) {                         \
   567       /* prefetch beyond q */                                                \
   568       Prefetch::write(q, interval);                                          \
   569       size_t size = block_size(q);                                           \
   570       compact_top = cp->space->forward(oop(q), size, cp, compact_top);       \
   571       q += size;                                                             \
   572       end_of_live = q;                                                       \
   573     } else {                                                                 \
   574       /* run over all the contiguous dead objects */                         \
   575       HeapWord* end = q;                                                     \
   576       do {                                                                   \
   577         /* prefetch beyond end */                                            \
   578         Prefetch::write(end, interval);                                      \
   579         end += block_size(end);                                              \
   580       } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\
   581                                                                              \
   582       /* see if we might want to pretend this object is alive so that        \
   583        * we don't have to compact quite as often.                            \
   584        */                                                                    \
   585       if (allowed_deadspace > 0 && q == compact_top) {                       \
   586         size_t sz = pointer_delta(end, q);                                   \
   587         if (insert_deadspace(allowed_deadspace, q, sz)) {                    \
   588           compact_top = cp->space->forward(oop(q), sz, cp, compact_top);     \
   589           q = end;                                                           \
   590           end_of_live = end;                                                 \
   591           continue;                                                          \
   592         }                                                                    \
   593       }                                                                      \
   594                                                                              \
   595       /* otherwise, it really is a free region. */                           \
   596                                                                              \
   597       /* for the previous LiveRange, record the end of the live objects. */  \
   598       if (liveRange) {                                                       \
   599         liveRange->set_end(q);                                               \
   600       }                                                                      \
   601                                                                              \
   602       /* record the current LiveRange object.                                \
   603        * liveRange->start() is overlaid on the mark word.                    \
   604        */                                                                    \
   605       liveRange = (LiveRange*)q;                                             \
   606       liveRange->set_start(end);                                             \
   607       liveRange->set_end(end);                                               \
   608                                                                              \
   609       /* see if this is the first dead region. */                            \
   610       if (q < first_dead) {                                                  \
   611         first_dead = q;                                                      \
   612       }                                                                      \
   613                                                                              \
   614       /* move on to the next object */                                       \
   615       q = end;                                                               \
   616     }                                                                        \
   617   }                                                                          \
   618                                                                              \
   619   assert(q == t, "just checking");                                           \
   620   if (liveRange != NULL) {                                                   \
   621     liveRange->set_end(q);                                                   \
   622   }                                                                          \
   623   _end_of_live = end_of_live;                                                \
   624   if (end_of_live < first_dead) {                                            \
   625     first_dead = end_of_live;                                                \
   626   }                                                                          \
   627   _first_dead = first_dead;                                                  \
   628                                                                              \
   629   /* save the compaction_top of the compaction space. */                     \
   630   cp->space->set_compaction_top(compact_top);                                \
   631 }
   633 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) {                             \
   634   /* adjust all the interior pointers to point at the new locations of objects  \
   635    * Used by MarkSweep::mark_sweep_phase3() */                                  \
   636                                                                                 \
   637   HeapWord* q = bottom();                                                       \
   638   HeapWord* t = _end_of_live;  /* Established by "prepare_for_compaction". */   \
   639                                                                                 \
   640   assert(_first_dead <= _end_of_live, "Stands to reason, no?");                 \
   641                                                                                 \
   642   if (q < t && _first_dead > q &&                                               \
   643       !oop(q)->is_gc_marked()) {                                                \
   644     /* we have a chunk of the space which hasn't moved and we've                \
   645      * reinitialized the mark word during the previous pass, so we can't        \
   646      * use is_gc_marked for the traversal. */                                   \
   647     HeapWord* end = _first_dead;                                                \
   648                                                                                 \
   649     while (q < end) {                                                           \
   650       /* I originally tried to conjoin "block_start(q) == q" to the             \
   651        * assertion below, but that doesn't work, because you can't              \
   652        * accurately traverse previous objects to get to the current one         \
   653        * after their pointers have been                                         \
   654        * updated, until the actual compaction is done.  dld, 4/00 */            \
   655       assert(block_is_obj(q),                                                   \
   656              "should be at block boundaries, and should be looking at objs");   \
   657                                                                                 \
   658       /* point all the oops to the new location */                              \
   659       size_t size = oop(q)->adjust_pointers();                                  \
   660       size = adjust_obj_size(size);                                             \
   661                                                                                 \
   662       q += size;                                                                \
   663     }                                                                           \
   664                                                                                 \
   665     if (_first_dead == t) {                                                     \
   666       q = t;                                                                    \
   667     } else {                                                                    \
   668       /* $$$ This is funky.  Using this to read the previously written          \
   669        * LiveRange.  See also use below. */                                     \
   670       q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer();                \
   671     }                                                                           \
   672   }                                                                             \
   673                                                                                 \
   674   const intx interval = PrefetchScanIntervalInBytes;                            \
   675                                                                                 \
   676   debug_only(HeapWord* prev_q = NULL);                                          \
   677   while (q < t) {                                                               \
   678     /* prefetch beyond q */                                                     \
   679     Prefetch::write(q, interval);                                               \
   680     if (oop(q)->is_gc_marked()) {                                               \
   681       /* q is alive */                                                          \
   682       /* point all the oops to the new location */                              \
   683       size_t size = oop(q)->adjust_pointers();                                  \
   684       size = adjust_obj_size(size);                                             \
   685       debug_only(prev_q = q);                                                   \
   686       q += size;                                                                \
   687     } else {                                                                    \
   688       /* q is not a live object, so its mark should point at the next           \
   689        * live object */                                                         \
   690       debug_only(prev_q = q);                                                   \
   691       q = (HeapWord*) oop(q)->mark()->decode_pointer();                         \
   692       assert(q > prev_q, "we should be moving forward through memory");         \
   693     }                                                                           \
   694   }                                                                             \
   695                                                                                 \
   696   assert(q == t, "just checking");                                              \
   697 }
   699 #define SCAN_AND_COMPACT(obj_size) {                                            \
   700   /* Copy all live objects to their new location                                \
   701    * Used by MarkSweep::mark_sweep_phase4() */                                  \
   702                                                                                 \
   703   HeapWord*       q = bottom();                                                 \
   704   HeapWord* const t = _end_of_live;                                             \
   705   debug_only(HeapWord* prev_q = NULL);                                          \
   706                                                                                 \
   707   if (q < t && _first_dead > q &&                                               \
   708       !oop(q)->is_gc_marked()) {                                                \
   709     debug_only(                                                                 \
   710     /* we have a chunk of the space which hasn't moved and we've reinitialized  \
   711      * the mark word during the previous pass, so we can't use is_gc_marked for \
   712      * the traversal. */                                                        \
   713     HeapWord* const end = _first_dead;                                          \
   714                                                                                 \
   715     while (q < end) {                                                           \
   716       size_t size = obj_size(q);                                                \
   717       assert(!oop(q)->is_gc_marked(),                                           \
   718              "should be unmarked (special dense prefix handling)");             \
   719       debug_only(prev_q = q);                                                   \
   720       q += size;                                                                \
   721     }                                                                           \
   722     )  /* debug_only */                                                         \
   723                                                                                 \
   724     if (_first_dead == t) {                                                     \
   725       q = t;                                                                    \
   726     } else {                                                                    \
   727       /* $$$ Funky */                                                           \
   728       q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer();               \
   729     }                                                                           \
   730   }                                                                             \
   731                                                                                 \
   732   const intx scan_interval = PrefetchScanIntervalInBytes;                       \
   733   const intx copy_interval = PrefetchCopyIntervalInBytes;                       \
   734   while (q < t) {                                                               \
   735     if (!oop(q)->is_gc_marked()) {                                              \
   736       /* mark is pointer to next marked oop */                                  \
   737       debug_only(prev_q = q);                                                   \
   738       q = (HeapWord*) oop(q)->mark()->decode_pointer();                         \
   739       assert(q > prev_q, "we should be moving forward through memory");         \
   740     } else {                                                                    \
   741       /* prefetch beyond q */                                                   \
   742       Prefetch::read(q, scan_interval);                                         \
   743                                                                                 \
   744       /* size and destination */                                                \
   745       size_t size = obj_size(q);                                                \
   746       HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee();                \
   747                                                                                 \
   748       /* prefetch beyond compaction_top */                                      \
   749       Prefetch::write(compaction_top, copy_interval);                           \
   750                                                                                 \
   751       /* copy object and reinit its mark */                                     \
   752       assert(q != compaction_top, "everything in this pass should be moving");  \
   753       Copy::aligned_conjoint_words(q, compaction_top, size);                    \
   754       oop(compaction_top)->init_mark();                                         \
   755       assert(oop(compaction_top)->klass() != NULL, "should have a class");      \
   756                                                                                 \
   757       debug_only(prev_q = q);                                                   \
   758       q += size;                                                                \
   759     }                                                                           \
   760   }                                                                             \
   761                                                                                 \
   762   /* Let's remember if we were empty before we did the compaction. */           \
   763   bool was_empty = used_region().is_empty();                                    \
   764   /* Reset space after compaction is complete */                                \
   765   reset_after_compaction();                                                     \
   766   /* We do this clear, below, since it has overloaded meanings for some */      \
   767   /* space subtypes.  For example, OffsetTableContigSpace's that were   */      \
   768   /* compacted into will have had their offset table thresholds updated */      \
   769   /* continuously, but those that weren't need to have their thresholds */      \
   770   /* re-initialized.  Also mangles unused area for debugging.           */      \
   771   if (used_region().is_empty()) {                                               \
   772     if (!was_empty) clear(SpaceDecorator::Mangle);                              \
   773   } else {                                                                      \
   774     if (ZapUnusedHeapArea) mangle_unused_area();                                \
   775   }                                                                             \
   776 }
   778 class GenSpaceMangler;
   780 // A space in which the free area is contiguous.  It therefore supports
   781 // faster allocation, and compaction.
   782 class ContiguousSpace: public CompactibleSpace {
   783   friend class OneContigSpaceCardGeneration;
   784   friend class VMStructs;
   785  protected:
   786   HeapWord* _top;
   787   HeapWord* _concurrent_iteration_safe_limit;
   788   // A helper for mangling the unused area of the space in debug builds.
   789   GenSpaceMangler* _mangler;
   791   GenSpaceMangler* mangler() { return _mangler; }
   793   // Allocation helpers (return NULL if full).
   794   inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value);
   795   inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value);
   797  public:
   798   ContiguousSpace();
   799   ~ContiguousSpace();
   801   virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space);
   802   virtual void clear(bool mangle_space);
   804   // Accessors
   805   HeapWord* top() const            { return _top;    }
   806   void set_top(HeapWord* value)    { _top = value; }
   808   virtual void set_saved_mark()    { _saved_mark_word = top();    }
   809   void reset_saved_mark()          { _saved_mark_word = bottom(); }
   811   WaterMark bottom_mark()     { return WaterMark(this, bottom()); }
   812   WaterMark top_mark()        { return WaterMark(this, top()); }
   813   WaterMark saved_mark()      { return WaterMark(this, saved_mark_word()); }
   814   bool saved_mark_at_top() const { return saved_mark_word() == top(); }
   816   // In debug mode mangle (write it with a particular bit
   817   // pattern) the unused part of a space.
   819   // Used to save the an address in a space for later use during mangling.
   820   void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN;
   821   // Used to save the space's current top for later use during mangling.
   822   void set_top_for_allocations() PRODUCT_RETURN;
   824   // Mangle regions in the space from the current top up to the
   825   // previously mangled part of the space.
   826   void mangle_unused_area() PRODUCT_RETURN;
   827   // Mangle [top, end)
   828   void mangle_unused_area_complete() PRODUCT_RETURN;
   829   // Mangle the given MemRegion.
   830   void mangle_region(MemRegion mr) PRODUCT_RETURN;
   832   // Do some sparse checking on the area that should have been mangled.
   833   void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
   834   // Check the complete area that should have been mangled.
   835   // This code may be NULL depending on the macro DEBUG_MANGLING.
   836   void check_mangled_unused_area_complete() PRODUCT_RETURN;
   838   // Size computations: sizes in bytes.
   839   size_t capacity() const        { return byte_size(bottom(), end()); }
   840   size_t used() const            { return byte_size(bottom(), top()); }
   841   size_t free() const            { return byte_size(top(),    end()); }
   843   // Override from space.
   844   bool is_in(const void* p) const;
   846   virtual bool is_free_block(const HeapWord* p) const;
   848   // In a contiguous space we have a more obvious bound on what parts
   849   // contain objects.
   850   MemRegion used_region() const { return MemRegion(bottom(), top()); }
   852   MemRegion used_region_at_save_marks() const {
   853     return MemRegion(bottom(), saved_mark_word());
   854   }
   856   // Allocation (return NULL if full)
   857   virtual HeapWord* allocate(size_t word_size);
   858   virtual HeapWord* par_allocate(size_t word_size);
   860   virtual bool obj_allocated_since_save_marks(const oop obj) const {
   861     return (HeapWord*)obj >= saved_mark_word();
   862   }
   864   // Iteration
   865   void oop_iterate(ExtendedOopClosure* cl);
   866   void oop_iterate(MemRegion mr, ExtendedOopClosure* cl);
   867   void object_iterate(ObjectClosure* blk);
   868   // For contiguous spaces this method will iterate safely over objects
   869   // in the space (i.e., between bottom and top) when at a safepoint.
   870   void safe_object_iterate(ObjectClosure* blk);
   871   void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
   872   // iterates on objects up to the safe limit
   873   HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
   874   HeapWord* concurrent_iteration_safe_limit() {
   875     assert(_concurrent_iteration_safe_limit <= top(),
   876            "_concurrent_iteration_safe_limit update missed");
   877     return _concurrent_iteration_safe_limit;
   878   }
   879   // changes the safe limit, all objects from bottom() to the new
   880   // limit should be properly initialized
   881   void set_concurrent_iteration_safe_limit(HeapWord* new_limit) {
   882     assert(new_limit <= top(), "uninitialized objects in the safe range");
   883     _concurrent_iteration_safe_limit = new_limit;
   884   }
   887 #if INCLUDE_ALL_GCS
   888   // In support of parallel oop_iterate.
   889   #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix)  \
   890     void par_oop_iterate(MemRegion mr, OopClosureType* blk);
   892     ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL)
   893   #undef ContigSpace_PAR_OOP_ITERATE_DECL
   894 #endif // INCLUDE_ALL_GCS
   896   // Compaction support
   897   virtual void reset_after_compaction() {
   898     assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space");
   899     set_top(compaction_top());
   900     // set new iteration safe limit
   901     set_concurrent_iteration_safe_limit(compaction_top());
   902   }
   903   virtual size_t minimum_free_block_size() const { return 0; }
   905   // Override.
   906   DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl,
   907                                      CardTableModRefBS::PrecisionStyle precision,
   908                                      HeapWord* boundary = NULL);
   910   // Apply "blk->do_oop" to the addresses of all reference fields in objects
   911   // starting with the _saved_mark_word, which was noted during a generation's
   912   // save_marks and is required to denote the head of an object.
   913   // Fields in objects allocated by applications of the closure
   914   // *are* included in the iteration.
   915   // Updates _saved_mark_word to point to just after the last object
   916   // iterated over.
   917 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix)  \
   918   void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk);
   920   ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL)
   921 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL
   923   // Same as object_iterate, but starting from "mark", which is required
   924   // to denote the start of an object.  Objects allocated by
   925   // applications of the closure *are* included in the iteration.
   926   virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk);
   928   // Very inefficient implementation.
   929   virtual HeapWord* block_start_const(const void* p) const;
   930   size_t block_size(const HeapWord* p) const;
   931   // If a block is in the allocated area, it is an object.
   932   bool block_is_obj(const HeapWord* p) const { return p < top(); }
   934   // Addresses for inlined allocation
   935   HeapWord** top_addr() { return &_top; }
   936   HeapWord** end_addr() { return &_end; }
   938   // Overrides for more efficient compaction support.
   939   void prepare_for_compaction(CompactPoint* cp);
   941   // PrintHeapAtGC support.
   942   virtual void print_on(outputStream* st) const;
   944   // Checked dynamic downcasts.
   945   virtual ContiguousSpace* toContiguousSpace() {
   946     return this;
   947   }
   949   // Debugging
   950   virtual void verify() const;
   952   // Used to increase collection frequency.  "factor" of 0 means entire
   953   // space.
   954   void allocate_temporary_filler(int factor);
   956 };
   959 // A dirty card to oop closure that does filtering.
   960 // It knows how to filter out objects that are outside of the _boundary.
   961 class Filtering_DCTOC : public DirtyCardToOopClosure {
   962 protected:
   963   // Override.
   964   void walk_mem_region(MemRegion mr,
   965                        HeapWord* bottom, HeapWord* top);
   967   // Walk the given memory region, from bottom to top, applying
   968   // the given oop closure to (possibly) all objects found. The
   969   // given oop closure may or may not be the same as the oop
   970   // closure with which this closure was created, as it may
   971   // be a filtering closure which makes use of the _boundary.
   972   // We offer two signatures, so the FilteringClosure static type is
   973   // apparent.
   974   virtual void walk_mem_region_with_cl(MemRegion mr,
   975                                        HeapWord* bottom, HeapWord* top,
   976                                        ExtendedOopClosure* cl) = 0;
   977   virtual void walk_mem_region_with_cl(MemRegion mr,
   978                                        HeapWord* bottom, HeapWord* top,
   979                                        FilteringClosure* cl) = 0;
   981 public:
   982   Filtering_DCTOC(Space* sp, ExtendedOopClosure* cl,
   983                   CardTableModRefBS::PrecisionStyle precision,
   984                   HeapWord* boundary) :
   985     DirtyCardToOopClosure(sp, cl, precision, boundary) {}
   986 };
   988 // A dirty card to oop closure for contiguous spaces
   989 // (ContiguousSpace and sub-classes).
   990 // It is a FilteringClosure, as defined above, and it knows:
   991 //
   992 // 1. That the actual top of any area in a memory region
   993 //    contained by the space is bounded by the end of the contiguous
   994 //    region of the space.
   995 // 2. That the space is really made up of objects and not just
   996 //    blocks.
   998 class ContiguousSpaceDCTOC : public Filtering_DCTOC {
   999 protected:
  1000   // Overrides.
  1001   HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj);
  1003   virtual void walk_mem_region_with_cl(MemRegion mr,
  1004                                        HeapWord* bottom, HeapWord* top,
  1005                                        ExtendedOopClosure* cl);
  1006   virtual void walk_mem_region_with_cl(MemRegion mr,
  1007                                        HeapWord* bottom, HeapWord* top,
  1008                                        FilteringClosure* cl);
  1010 public:
  1011   ContiguousSpaceDCTOC(ContiguousSpace* sp, ExtendedOopClosure* cl,
  1012                        CardTableModRefBS::PrecisionStyle precision,
  1013                        HeapWord* boundary) :
  1014     Filtering_DCTOC(sp, cl, precision, boundary)
  1015   {}
  1016 };
  1019 // Class EdenSpace describes eden-space in new generation.
  1021 class DefNewGeneration;
  1023 class EdenSpace : public ContiguousSpace {
  1024   friend class VMStructs;
  1025  private:
  1026   DefNewGeneration* _gen;
  1028   // _soft_end is used as a soft limit on allocation.  As soft limits are
  1029   // reached, the slow-path allocation code can invoke other actions and then
  1030   // adjust _soft_end up to a new soft limit or to end().
  1031   HeapWord* _soft_end;
  1033  public:
  1034   EdenSpace(DefNewGeneration* gen) :
  1035    _gen(gen), _soft_end(NULL) {}
  1037   // Get/set just the 'soft' limit.
  1038   HeapWord* soft_end()               { return _soft_end; }
  1039   HeapWord** soft_end_addr()         { return &_soft_end; }
  1040   void set_soft_end(HeapWord* value) { _soft_end = value; }
  1042   // Override.
  1043   void clear(bool mangle_space);
  1045   // Set both the 'hard' and 'soft' limits (_end and _soft_end).
  1046   void set_end(HeapWord* value) {
  1047     set_soft_end(value);
  1048     ContiguousSpace::set_end(value);
  1051   // Allocation (return NULL if full)
  1052   HeapWord* allocate(size_t word_size);
  1053   HeapWord* par_allocate(size_t word_size);
  1054 };
  1056 // Class ConcEdenSpace extends EdenSpace for the sake of safe
  1057 // allocation while soft-end is being modified concurrently
  1059 class ConcEdenSpace : public EdenSpace {
  1060  public:
  1061   ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { }
  1063   // Allocation (return NULL if full)
  1064   HeapWord* par_allocate(size_t word_size);
  1065 };
  1068 // A ContigSpace that Supports an efficient "block_start" operation via
  1069 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with
  1070 // other spaces.)  This is the abstract base class for old generation
  1071 // (tenured) spaces.
  1073 class OffsetTableContigSpace: public ContiguousSpace {
  1074   friend class VMStructs;
  1075  protected:
  1076   BlockOffsetArrayContigSpace _offsets;
  1077   Mutex _par_alloc_lock;
  1079  public:
  1080   // Constructor
  1081   OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray,
  1082                          MemRegion mr);
  1084   void set_bottom(HeapWord* value);
  1085   void set_end(HeapWord* value);
  1087   void clear(bool mangle_space);
  1089   inline HeapWord* block_start_const(const void* p) const;
  1091   // Add offset table update.
  1092   virtual inline HeapWord* allocate(size_t word_size);
  1093   inline HeapWord* par_allocate(size_t word_size);
  1095   // MarkSweep support phase3
  1096   virtual HeapWord* initialize_threshold();
  1097   virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end);
  1099   virtual void print_on(outputStream* st) const;
  1101   // Debugging
  1102   void verify() const;
  1103 };
  1106 // Class TenuredSpace is used by TenuredGeneration
  1108 class TenuredSpace: public OffsetTableContigSpace {
  1109   friend class VMStructs;
  1110  protected:
  1111   // Mark sweep support
  1112   size_t allowed_dead_ratio() const;
  1113  public:
  1114   // Constructor
  1115   TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray,
  1116                MemRegion mr) :
  1117     OffsetTableContigSpace(sharedOffsetArray, mr) {}
  1118 };
  1119 #endif // SHARE_VM_MEMORY_SPACE_HPP

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