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 /*

  * Copyright (c) 1997, 2013, 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.

  *

  */

 #ifndef SHARE_VM_MEMORY_ALLOCATION_HPP

 #define SHARE_VM_MEMORY_ALLOCATION_HPP

 #include "runtime/globals.hpp"

 #include "utilities/globalDefinitions.hpp"

 #include "utilities/macros.hpp"

 #ifdef COMPILER1

 #include "c1/c1_globals.hpp"

 #endif

 #ifdef COMPILER2

 #include "opto/c2_globals.hpp"

 #endif

 #include <new>

 #define ARENA_ALIGN_M1 (((size_t)(ARENA_AMALLOC_ALIGNMENT)) - 1)

 #define ARENA_ALIGN_MASK (~((size_t)ARENA_ALIGN_M1))

 #define ARENA_ALIGN(x) ((((size_t)(x)) + ARENA_ALIGN_M1) & ARENA_ALIGN_MASK)

 // noinline attribute

 #ifdef _WINDOWS

   #define _NOINLINE_  __declspec(noinline)

 #else

   #if __GNUC__ < 3    // gcc 2.x does not support noinline attribute

     #define _NOINLINE_

   #else

     #define _NOINLINE_ __attribute__ ((noinline))

   #endif

 #endif

 class AllocFailStrategy {

 public:

   enum AllocFailEnum { EXIT_OOM, RETURN_NULL };

 };

 typedef AllocFailStrategy::AllocFailEnum AllocFailType;

 // All classes in the virtual machine must be subclassed

 // by one of the following allocation classes:

 //

 // For objects allocated in the resource area (see resourceArea.hpp).

 // - ResourceObj

 //

 // For objects allocated in the C-heap (managed by: free & malloc).

 // - CHeapObj

 //

 // For objects allocated on the stack.

 // - StackObj

 //

 // For embedded objects.

 // - ValueObj

 //

 // For classes used as name spaces.

 // - AllStatic

 //

 // For classes in Metaspace (class data)

 // - MetaspaceObj

 //

 // The printable subclasses are used for debugging and define virtual

 // member functions for printing. Classes that avoid allocating the

 // vtbl entries in the objects should therefore not be the printable

 // subclasses.

 //

 // The following macros and function should be used to allocate memory

 // directly in the resource area or in the C-heap:

 //

 //   NEW_RESOURCE_ARRAY(type,size)

 //   NEW_RESOURCE_OBJ(type)

 //   NEW_C_HEAP_ARRAY(type,size)

 //   NEW_C_HEAP_OBJ(type)

 //   char* AllocateHeap(size_t size, const char* name);

 //   void  FreeHeap(void* p);

 //

 // C-heap allocation can be traced using +PrintHeapAllocation.

 // malloc and free should therefore never called directly.

 // Base class for objects allocated in the C-heap.

 // In non product mode we introduce a super class for all allocation classes

 // that supports printing.

 // We avoid the superclass in product mode since some C++ compilers add

 // a word overhead for empty super classes.

 #ifdef PRODUCT

 #define ALLOCATION_SUPER_CLASS_SPEC

 #else

 #define ALLOCATION_SUPER_CLASS_SPEC : public AllocatedObj

 class AllocatedObj {

  public:

   // Printing support

   void print() const;

   void print_value() const;

   virtual void print_on(outputStream* st) const;

   virtual void print_value_on(outputStream* st) const;

 };

 #endif

 /*

  * MemoryType bitmap layout:

  * | 16 15 14 13 12 11 10 09 | 08 07 06 05 | 04 03 02 01 |

  * |      memory type        |   object    | reserved    |

  * |                         |     type    |             |

  */

 enum MemoryType {

   // Memory type by sub systems. It occupies lower byte.

   mtNone              = 0x0000,  // undefined

   mtClass             = 0x0100,  // memory class for Java classes

   mtThread            = 0x0200,  // memory for thread objects

   mtThreadStack       = 0x0300,

   mtCode              = 0x0400,  // memory for generated code

   mtGC                = 0x0500,  // memory for GC

   mtCompiler          = 0x0600,  // memory for compiler

   mtInternal          = 0x0700,  // memory used by VM, but does not belong to

                                  // any of above categories, and not used for

                                  // native memory tracking

   mtOther             = 0x0800,  // memory not used by VM

   mtSymbol            = 0x0900,  // symbol

   mtNMT               = 0x0A00,  // memory used by native memory tracking

   mtChunk             = 0x0B00,  // chunk that holds content of arenas

   mtJavaHeap          = 0x0C00,  // Java heap

   mtClassShared       = 0x0D00,  // class data sharing

   mtTest              = 0x0E00,  // Test type for verifying NMT

   mt_number_of_types  = 0x000E,  // number of memory types (mtDontTrack

                                  // is not included as validate type)

   mtDontTrack         = 0x0F00,  // memory we do not or cannot track

   mt_masks            = 0x7F00,

   // object type mask

   otArena             = 0x0010, // an arena object

   otNMTRecorder       = 0x0020, // memory recorder object

   ot_masks            = 0x00F0

 };

 #define IS_MEMORY_TYPE(flags, type) ((flags & mt_masks) == type)

 #define HAS_VALID_MEMORY_TYPE(flags)((flags & mt_masks) != mtNone)

 #define FLAGS_TO_MEMORY_TYPE(flags) (flags & mt_masks)

 #define IS_ARENA_OBJ(flags)         ((flags & ot_masks) == otArena)

 #define IS_NMT_RECORDER(flags)      ((flags & ot_masks) == otNMTRecorder)

 #define NMT_CAN_TRACK(flags)        (!IS_NMT_RECORDER(flags) && !(IS_MEMORY_TYPE(flags, mtDontTrack)))

 typedef unsigned short MEMFLAGS;

 #if INCLUDE_NMT

 extern bool NMT_track_callsite;

 #else

 const bool NMT_track_callsite = false;

 #endif // INCLUDE_NMT

 // debug build does not inline

 #if defined(_NMT_NOINLINE_)

   #define CURRENT_PC       (NMT_track_callsite ? os::get_caller_pc(1) : 0)

   #define CALLER_PC        (NMT_track_callsite ? os::get_caller_pc(2) : 0)

   #define CALLER_CALLER_PC (NMT_track_callsite ? os::get_caller_pc(3) : 0)

 #else

   #define CURRENT_PC      (NMT_track_callsite? os::get_caller_pc(0) : 0)

   #define CALLER_PC       (NMT_track_callsite ? os::get_caller_pc(1) : 0)

   #define CALLER_CALLER_PC (NMT_track_callsite ? os::get_caller_pc(2) : 0)

 #endif

 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC {

  public:

   _NOINLINE_ void* operator new(size_t size, address caller_pc = 0);

   _NOINLINE_ void* operator new (size_t size, const std::nothrow_t&  nothrow_constant,

                                address caller_pc = 0);

   void  operator delete(void* p);

 };

 // Base class for objects allocated on the stack only.

 // Calling new or delete will result in fatal error.

 class StackObj ALLOCATION_SUPER_CLASS_SPEC {

  private:

   void* operator new(size_t size);

   void  operator delete(void* p);

 };

 // Base class for objects used as value objects.

 // Calling new or delete will result in fatal error.

 //

 // Portability note: Certain compilers (e.g. gcc) will

 // always make classes bigger if it has a superclass, even

 // if the superclass does not have any virtual methods or

 // instance fields. The HotSpot implementation relies on this

 // not to happen. So never make a ValueObj class a direct subclass

 // of this object, but use the VALUE_OBJ_CLASS_SPEC class instead, e.g.,

 // like this:

 //

 //   class A VALUE_OBJ_CLASS_SPEC {

 //     ...

 //   }

 //

 // With gcc and possible other compilers the VALUE_OBJ_CLASS_SPEC can

 // be defined as a an empty string "".

 //

 class _ValueObj {

  private:

   void* operator new(size_t size);

   void operator delete(void* p);

 };

 // Base class for objects stored in Metaspace.

 // Calling delete will result in fatal error.

 //

 // Do not inherit from something with a vptr because this class does

 // not introduce one.  This class is used to allocate both shared read-only

 // and shared read-write classes.

 //

 class ClassLoaderData;

 class MetaspaceObj {

  public:

   bool is_metadata() const;

   bool is_metaspace_object() const;  // more specific test but slower

   bool is_shared() const;

   void print_address_on(outputStream* st) const;  // nonvirtual address printing

   void* operator new(size_t size, ClassLoaderData* loader_data,

                      size_t word_size, bool read_only, Thread* thread);

                      // can't use TRAPS from this header file.

   void operator delete(void* p) { ShouldNotCallThis(); }

 };

 // Base class for classes that constitute name spaces.

 class AllStatic {

  public:

   AllStatic()  { ShouldNotCallThis(); }

   ~AllStatic() { ShouldNotCallThis(); }

 };

 //------------------------------Chunk------------------------------------------

 // Linked list of raw memory chunks

 class Chunk: CHeapObj<mtChunk> {

   friend class VMStructs;

  protected:

   Chunk*       _next;     // Next Chunk in list

   const size_t _len;      // Size of this Chunk

  public:

   void* operator new(size_t size, AllocFailType alloc_failmode, size_t length);

   void  operator delete(void* p);

   Chunk(size_t length);

   enum {

     // default sizes; make them slightly smaller than 2**k to guard against

     // buddy-system style malloc implementations

 #ifdef _LP64

     slack      = 40,            // [RGV] Not sure if this is right, but make it

                                 //       a multiple of 8.

 #else

     slack      = 20,            // suspected sizeof(Chunk) + internal malloc headers

 #endif

     init_size  =  1*K  - slack, // Size of first chunk

     medium_size= 10*K  - slack, // Size of medium-sized chunk

     size       = 32*K  - slack, // Default size of an Arena chunk (following the first)

     non_pool_size = init_size + 32 // An initial size which is not one of above

   };

   void chop();                  // Chop this chunk

   void next_chop();             // Chop next chunk

   static size_t aligned_overhead_size(void) { return ARENA_ALIGN(sizeof(Chunk)); }

   static size_t aligned_overhead_size(size_t byte_size) { return ARENA_ALIGN(byte_size); }

   size_t length() const         { return _len;  }

   Chunk* next() const           { return _next;  }

   void set_next(Chunk* n)       { _next = n;  }

   // Boundaries of data area (possibly unused)

   char* bottom() const          { return ((char*) this) + aligned_overhead_size();  }

   char* top()    const          { return bottom() + _len; }

   bool contains(char* p) const  { return bottom() <= p && p <= top(); }

   // Start the chunk_pool cleaner task

   static void start_chunk_pool_cleaner_task();

   static void clean_chunk_pool();

 };

 //------------------------------Arena------------------------------------------

 // Fast allocation of memory

 class Arena : public CHeapObj<mtNone|otArena> {

 protected:

   friend class ResourceMark;

   friend class HandleMark;

   friend class NoHandleMark;

   friend class VMStructs;

   Chunk *_first;                // First chunk

   Chunk *_chunk;                // current chunk

   char *_hwm, *_max;            // High water mark and max in current chunk

   // Get a new Chunk of at least size x

   void* grow(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);

   size_t _size_in_bytes;        // Size of arena (used for native memory tracking)

   NOT_PRODUCT(static julong _bytes_allocated;) // total #bytes allocated since start

   friend class AllocStats;

   debug_only(void* malloc(size_t size);)

   debug_only(void* internal_malloc_4(size_t x);)

   NOT_PRODUCT(void inc_bytes_allocated(size_t x);)

   void signal_out_of_memory(size_t request, const char* whence) const;

   bool check_for_overflow(size_t request, const char* whence,

       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) const {

     if (UINTPTR_MAX - request < (uintptr_t)_hwm) {

       if (alloc_failmode == AllocFailStrategy::RETURN_NULL) {

         return false;

       }

       signal_out_of_memory(request, whence);

     }

     return true;

  }

  public:

   Arena();

   Arena(size_t init_size);

   ~Arena();

   void  destruct_contents();

   char* hwm() const             { return _hwm; }

   // new operators

   void* operator new (size_t size);

   void* operator new (size_t size, const std::nothrow_t& nothrow_constant);

   // dynamic memory type tagging

   void* operator new(size_t size, MEMFLAGS flags);

   void* operator new(size_t size, const std::nothrow_t& nothrow_constant, MEMFLAGS flags);

   void  operator delete(void* p);

   // Fast allocate in the arena.  Common case is: pointer test + increment.

   void* Amalloc(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {

     assert(is_power_of_2(ARENA_AMALLOC_ALIGNMENT) , "should be a power of 2");

     x = ARENA_ALIGN(x);

     debug_only(if (UseMallocOnly) return malloc(x);)

     if (!check_for_overflow(x, "Arena::Amalloc", alloc_failmode))

       return NULL;

     NOT_PRODUCT(inc_bytes_allocated(x);)

     if (_hwm + x > _max) {

       return grow(x, alloc_failmode);

     } else {

       char *old = _hwm;

       _hwm += x;

       return old;

     }

   }

   // Further assume size is padded out to words

   void *Amalloc_4(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {

     assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );

     debug_only(if (UseMallocOnly) return malloc(x);)

     if (!check_for_overflow(x, "Arena::Amalloc_4", alloc_failmode))

       return NULL;

     NOT_PRODUCT(inc_bytes_allocated(x);)

     if (_hwm + x > _max) {

       return grow(x, alloc_failmode);

     } else {

       char *old = _hwm;

       _hwm += x;

       return old;

     }

   }

   // Allocate with 'double' alignment. It is 8 bytes on sparc.

   // In other cases Amalloc_D() should be the same as Amalloc_4().

   void* Amalloc_D(size_t x, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) {

     assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );

     debug_only(if (UseMallocOnly) return malloc(x);)

 #if defined(SPARC) && !defined(_LP64)

 #define DALIGN_M1 7

     size_t delta = (((size_t)_hwm + DALIGN_M1) & ~DALIGN_M1) - (size_t)_hwm;

     x += delta;

 #endif

     if (!check_for_overflow(x, "Arena::Amalloc_D", alloc_failmode))

       return NULL;

     NOT_PRODUCT(inc_bytes_allocated(x);)

     if (_hwm + x > _max) {

       return grow(x, alloc_failmode); // grow() returns a result aligned >= 8 bytes.

     } else {

       char *old = _hwm;

       _hwm += x;

 #if defined(SPARC) && !defined(_LP64)

       old += delta; // align to 8-bytes

 #endif

       return old;

     }

   }

   // Fast delete in area.  Common case is: NOP (except for storage reclaimed)

   void Afree(void *ptr, size_t size) {

 #ifdef ASSERT

     if (ZapResourceArea) memset(ptr, badResourceValue, size); // zap freed memory

     if (UseMallocOnly) return;

 #endif

     if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;

   }

   void *Arealloc( void *old_ptr, size_t old_size, size_t new_size,

       AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);

   // Move contents of this arena into an empty arena

   Arena *move_contents(Arena *empty_arena);

   // Determine if pointer belongs to this Arena or not.

   bool contains( const void *ptr ) const;

   // Total of all chunks in use (not thread-safe)

   size_t used() const;

   // Total # of bytes used

   size_t size_in_bytes() const         {  return _size_in_bytes; };

   void set_size_in_bytes(size_t size);

   static void free_malloced_objects(Chunk* chunk, char* hwm, char* max, char* hwm2)  PRODUCT_RETURN;

   static void free_all(char** start, char** end)                                     PRODUCT_RETURN;

   // how many arena instances

   NOT_PRODUCT(static volatile jint _instance_count;)

 private:

   // Reset this Arena to empty, access will trigger grow if necessary

   void   reset(void) {

     _first = _chunk = NULL;

     _hwm = _max = NULL;

     set_size_in_bytes(0);

   }

 };

 // One of the following macros must be used when allocating

 // an array or object from an arena

 #define NEW_ARENA_ARRAY(arena, type, size) \

   (type*) (arena)->Amalloc((size) * sizeof(type))

 #define REALLOC_ARENA_ARRAY(arena, type, old, old_size, new_size)    \

   (type*) (arena)->Arealloc((char*)(old), (old_size) * sizeof(type), \

                             (new_size) * sizeof(type) )

 #define FREE_ARENA_ARRAY(arena, type, old, size) \

   (arena)->Afree((char*)(old), (size) * sizeof(type))

 #define NEW_ARENA_OBJ(arena, type) \

   NEW_ARENA_ARRAY(arena, type, 1)

 //%note allocation_1

 extern char* resource_allocate_bytes(size_t size,

     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);

 extern char* resource_allocate_bytes(Thread* thread, size_t size,

     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);

 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size,

     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);

 extern void resource_free_bytes( char *old, size_t size );

 //----------------------------------------------------------------------

 // Base class for objects allocated in the resource area per default.

 // Optionally, objects may be allocated on the C heap with

 // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena)

 // ResourceObj's can be allocated within other objects, but don't use

 // new or delete (allocation_type is unknown).  If new is used to allocate,

 // use delete to deallocate.

 class ResourceObj ALLOCATION_SUPER_CLASS_SPEC {

  public:

   enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 };

   static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN;

 #ifdef ASSERT

  private:

   // When this object is allocated on stack the new() operator is not

   // called but garbage on stack may look like a valid allocation_type.

   // Store negated 'this' pointer when new() is called to distinguish cases.

   // Use second array's element for verification value to distinguish garbage.

   uintptr_t _allocation_t[2];

   bool is_type_set() const;

  public:

   allocation_type get_allocation_type() const;

   bool allocated_on_stack()    const { return get_allocation_type() == STACK_OR_EMBEDDED; }

   bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; }

   bool allocated_on_C_heap()   const { return get_allocation_type() == C_HEAP; }

   bool allocated_on_arena()    const { return get_allocation_type() == ARENA; }

   ResourceObj(); // default construtor

   ResourceObj(const ResourceObj& r); // default copy construtor

   ResourceObj& operator=(const ResourceObj& r); // default copy assignment

   ~ResourceObj();

 #endif // ASSERT

  public:

   void* operator new(size_t size, allocation_type type, MEMFLAGS flags);

   void* operator new(size_t size, const std::nothrow_t&  nothrow_constant,

       allocation_type type, MEMFLAGS flags);

   void* operator new(size_t size, Arena *arena) {

       address res = (address)arena->Amalloc(size);

       DEBUG_ONLY(set_allocation_type(res, ARENA);)

       return res;

   }

   void* operator new(size_t size) {

       address res = (address)resource_allocate_bytes(size);

       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)

       return res;

   }

   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) {

       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);

       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)

       return res;

   }

   void  operator delete(void* p);

 };

 // One of the following macros must be used when allocating an array

 // or object to determine whether it should reside in the C heap on in

 // the resource area.

 #define NEW_RESOURCE_ARRAY(type, size)\

   (type*) resource_allocate_bytes((size) * sizeof(type))

 #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\

   (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL)

 #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\

   (type*) resource_allocate_bytes(thread, (size) * sizeof(type))

 #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\

   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type) )

 #define FREE_RESOURCE_ARRAY(type, old, size)\

   resource_free_bytes((char*)(old), (size) * sizeof(type))

 #define FREE_FAST(old)\

     /* nop */

 #define NEW_RESOURCE_OBJ(type)\

   NEW_RESOURCE_ARRAY(type, 1)

 #define NEW_C_HEAP_ARRAY(type, size, memflags)\

   (type*) (AllocateHeap((size) * sizeof(type), memflags))

 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\

   (type*) (ReallocateHeap((char*)old, (size) * sizeof(type), memflags))

 #define FREE_C_HEAP_ARRAY(type,old,memflags) \

   FreeHeap((char*)(old), memflags)

 #define NEW_C_HEAP_OBJ(type, memflags)\

   NEW_C_HEAP_ARRAY(type, 1, memflags)

 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\

   (type*) (AllocateHeap((size) * sizeof(type), memflags, pc))

 #define REALLOC_C_HEAP_ARRAY2(type, old, size, memflags, pc)\

   (type*) (ReallocateHeap((char*)old, (size) * sizeof(type), memflags, pc))

 #define NEW_C_HEAP_OBJ2(type, memflags, pc)\

   NEW_C_HEAP_ARRAY2(type, 1, memflags, pc)

 extern bool warn_new_operator;

 // for statistics

 #ifndef PRODUCT

 class AllocStats : StackObj {

   julong start_mallocs, start_frees;

   julong start_malloc_bytes, start_mfree_bytes, start_res_bytes;

  public:

   AllocStats();

   julong num_mallocs();    // since creation of receiver

   julong alloc_bytes();

   julong num_frees();

   julong free_bytes();

   julong resource_bytes();

   void   print();

 };

 #endif

 //------------------------------ReallocMark---------------------------------

 // Code which uses REALLOC_RESOURCE_ARRAY should check an associated

 // ReallocMark, which is declared in the same scope as the reallocated

 // pointer.  Any operation that could __potentially__ cause a reallocation

 // should check the ReallocMark.

 class ReallocMark: public StackObj {

 protected:

   NOT_PRODUCT(int _nesting;)

 public:

   ReallocMark()   PRODUCT_RETURN;

   void check()    PRODUCT_RETURN;

 };

 // Helper class to allocate arrays that may become large.

 // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit

 // and uses mapped memory for larger allocations.

 // Most OS mallocs do something similar but Solaris malloc does not revert

 // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit

 // is set so that we always use malloc except for Solaris where we set the

 // limit to get mapped memory.

 template <class E, MEMFLAGS F>

 class ArrayAllocator : StackObj {

   char* _addr;

   bool _use_malloc;

   size_t _size;

  public:

   ArrayAllocator() : _addr(NULL), _use_malloc(false), _size(0) { }

   ~ArrayAllocator() { free(); }

   E* allocate(size_t length);

   void free();

 };

 #endif // SHARE_VM_MEMORY_ALLOCATION_HPP