1 /*
  2  * Copyright (c) 1997, 2019, 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 #ifndef SHARE_MEMORY_ALLOCATION_HPP
 26 #define SHARE_MEMORY_ALLOCATION_HPP
 27 
 28 #include "utilities/globalDefinitions.hpp"
 29 #include "utilities/macros.hpp"
 30 
 31 #include <new>
 32 
 33 class outputStream;
 34 class Thread;
 35 
 36 class AllocFailStrategy {
 37 public:
 38   enum AllocFailEnum { EXIT_OOM, RETURN_NULL };
 39 };
 40 typedef AllocFailStrategy::AllocFailEnum AllocFailType;
 41 
 42 // The virtual machine must never call one of the implicitly declared
 43 // global allocation or deletion functions.  (Such calls may result in
 44 // link-time or run-time errors.)  For convenience and documentation of
 45 // intended use, classes in the virtual machine may be derived from one
 46 // of the following allocation classes, some of which define allocation
 47 // and deletion functions.
 48 // Note: std::malloc and std::free should never called directly.
 49 
 50 //
 51 // For objects allocated in the resource area (see resourceArea.hpp).
 52 // - ResourceObj
 53 //
 54 // For objects allocated in the C-heap (managed by: free & malloc and tracked with NMT)
 55 // - CHeapObj
 56 //
 57 // For objects allocated on the stack.
 58 // - StackObj
 59 //
 60 // For classes used as name spaces.
 61 // - AllStatic
 62 //
 63 // For classes in Metaspace (class data)
 64 // - MetaspaceObj
 65 //
 66 // The printable subclasses are used for debugging and define virtual
 67 // member functions for printing. Classes that avoid allocating the
 68 // vtbl entries in the objects should therefore not be the printable
 69 // subclasses.
 70 //
 71 // The following macros and function should be used to allocate memory
 72 // directly in the resource area or in the C-heap, The _OBJ variants
 73 // of the NEW/FREE_C_HEAP macros are used for alloc/dealloc simple
 74 // objects which are not inherited from CHeapObj, note constructor and
 75 // destructor are not called. The preferable way to allocate objects
 76 // is using the new operator.
 77 //
 78 // WARNING: The array variant must only be used for a homogenous array
 79 // where all objects are of the exact type specified. If subtypes are
 80 // stored in the array then must pay attention to calling destructors
 81 // at needed.
 82 //
 83 // NEW_RESOURCE_ARRAY*
 84 // REALLOC_RESOURCE_ARRAY*
 85 // FREE_RESOURCE_ARRAY*
 86 // NEW_RESOURCE_OBJ*
 87 // NEW_C_HEAP_ARRAY*
 88 // REALLOC_C_HEAP_ARRAY*
 89 // FREE_C_HEAP_ARRAY*
 90 // NEW_C_HEAP_OBJ*
 91 // FREE_C_HEAP_OBJ
 92 //
 93 // char* AllocateHeap(size_t size, MEMFLAGS flags, const NativeCallStack& stack, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 94 // char* AllocateHeap(size_t size, MEMFLAGS flags, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 95 // char* ReallocateHeap(char *old, size_t size, MEMFLAGS flag, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
 96 // void FreeHeap(void* p);
 97 //
 98 // In non product mode we introduce a super class for all allocation classes
 99 // that supports printing.
100 // We avoid the superclass in product mode to save space.
101 
102 #ifdef PRODUCT
103 #define ALLOCATION_SUPER_CLASS_SPEC
104 #else
105 #define ALLOCATION_SUPER_CLASS_SPEC : public AllocatedObj
106 class AllocatedObj {
107  public:
108   // Printing support
109   void print() const;
110   void print_value() const;
111 
112   virtual void print_on(outputStream* st) const;
113   virtual void print_value_on(outputStream* st) const;
114 };
115 #endif
116 
117 #define MEMORY_TYPES_DO(f) \
118   /* Memory type by sub systems. It occupies lower byte. */  \
119   f(mtJavaHeap,      "Java Heap")   /* Java heap                                 */ \
120   f(mtClass,         "Class")       /* Java classes                              */ \
121   f(mtThread,        "Thread")      /* thread objects                            */ \
122   f(mtThreadStack,   "Thread Stack")                                                \
123   f(mtCode,          "Code")        /* generated code                            */ \
124   f(mtGC,            "GC")                                                          \
125   f(mtCompiler,      "Compiler")                                                    \
126   f(mtJVMCI,         "JVMCI")                                                       \
127   f(mtInternal,      "Internal")    /* memory used by VM, but does not belong to */ \
128                                     /* any of above categories, and not used by  */ \
129                                     /* NMT                                       */ \
130   f(mtOther,         "Other")       /* memory not used by VM                     */ \
131   f(mtSymbol,        "Symbol")                                                      \
132   f(mtNMT,           "Native Memory Tracking")  /* memory used by NMT            */ \
133   f(mtClassShared,   "Shared class space")      /* class data sharing            */ \
134   f(mtChunk,         "Arena Chunk") /* chunk that holds content of arenas        */ \
135   f(mtTest,          "Test")        /* Test type for verifying NMT               */ \
136   f(mtTracing,       "Tracing")                                                     \
137   f(mtLogging,       "Logging")                                                     \
138   f(mtStatistics,    "Statistics")                                                  \
139   f(mtArguments,     "Arguments")                                                   \
140   f(mtModule,        "Module")                                                      \
141   f(mtSafepoint,     "Safepoint")                                                   \
142   f(mtSynchronizer,  "Synchronization")                                             \
143   f(mtNone,          "Unknown")                                                     \
144   //end
145 
146 #define MEMORY_TYPE_DECLARE_ENUM(type, human_readable) \
147   type,
148 
149 /*
150  * Memory types
151  */
152 enum MemoryType {
153   MEMORY_TYPES_DO(MEMORY_TYPE_DECLARE_ENUM)
154   mt_number_of_types   // number of memory types (mtDontTrack
155                        // is not included as validate type)
156 };
157 
158 typedef MemoryType MEMFLAGS;
159 
160 
161 #if INCLUDE_NMT
162 
163 extern bool NMT_track_callsite;
164 
165 #else
166 
167 const bool NMT_track_callsite = false;
168 
169 #endif // INCLUDE_NMT
170 
171 class NativeCallStack;
172 
173 
174 char* AllocateHeap(size_t size,
175                    MEMFLAGS flags,
176                    const NativeCallStack& stack,
177                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
178 char* AllocateHeap(size_t size,
179                    MEMFLAGS flags,
180                    AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
181 
182 char* ReallocateHeap(char *old,
183                      size_t size,
184                      MEMFLAGS flag,
185                      AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
186 
187 void FreeHeap(void* p);
188 
189 template <MEMFLAGS F> class CHeapObj ALLOCATION_SUPER_CLASS_SPEC {
190  public:
191   ALWAYSINLINE void* operator new(size_t size) throw() {
192     return (void*)AllocateHeap(size, F);
193   }
194 
195   ALWAYSINLINE void* operator new(size_t size,
196                                   const NativeCallStack& stack) throw() {
197     return (void*)AllocateHeap(size, F, stack);
198   }
199 
200   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&,
201                                   const NativeCallStack& stack) throw() {
202     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
203   }
204 
205   ALWAYSINLINE void* operator new(size_t size, const std::nothrow_t&) throw() {
206     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
207   }
208 
209   ALWAYSINLINE void* operator new[](size_t size) throw() {
210     return (void*)AllocateHeap(size, F);
211   }
212 
213   ALWAYSINLINE void* operator new[](size_t size,
214                                   const NativeCallStack& stack) throw() {
215     return (void*)AllocateHeap(size, F, stack);
216   }
217 
218   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&,
219                                     const NativeCallStack& stack) throw() {
220     return (void*)AllocateHeap(size, F, stack, AllocFailStrategy::RETURN_NULL);
221   }
222 
223   ALWAYSINLINE void* operator new[](size_t size, const std::nothrow_t&) throw() {
224     return (void*)AllocateHeap(size, F, AllocFailStrategy::RETURN_NULL);
225   }
226 
227   void  operator delete(void* p)     { FreeHeap(p); }
228   void  operator delete [] (void* p) { FreeHeap(p); }
229 };
230 
231 // Base class for objects allocated on the stack only.
232 // Calling new or delete will result in fatal error.
233 
234 class StackObj ALLOCATION_SUPER_CLASS_SPEC {
235  private:
236   void* operator new(size_t size) throw();
237   void* operator new [](size_t size) throw();
238   void  operator delete(void* p);
239   void  operator delete [](void* p);
240 };
241 
242 // Base class for objects stored in Metaspace.
243 // Calling delete will result in fatal error.
244 //
245 // Do not inherit from something with a vptr because this class does
246 // not introduce one.  This class is used to allocate both shared read-only
247 // and shared read-write classes.
248 //
249 
250 class ClassLoaderData;
251 class MetaspaceClosure;
252 
253 class MetaspaceObj {
254   friend class VMStructs;
255   // When CDS is enabled, all shared metaspace objects are mapped
256   // into a single contiguous memory block, so we can use these
257   // two pointers to quickly determine if something is in the
258   // shared metaspace.
259   // When CDS is not enabled, both pointers are set to NULL.
260   static void* _shared_metaspace_base;  // (inclusive) low address
261   static void* _shared_metaspace_top;   // (exclusive) high address
262 
263  public:
264 
265   // Returns true if the pointer points to a valid MetaspaceObj. A valid
266   // MetaspaceObj is MetaWord-aligned and contained within either
267   // non-shared or shared metaspace.
268   static bool is_valid(const MetaspaceObj* p);
269 
270   static bool is_shared(const MetaspaceObj* p) {
271     // If no shared metaspace regions are mapped, _shared_metaspace_{base,top} will
272     // both be NULL and all values of p will be rejected quickly.
273     return (((void*)p) < _shared_metaspace_top &&
274             ((void*)p) >= _shared_metaspace_base);
275   }
276   bool is_shared() const { return MetaspaceObj::is_shared(this); }
277 
278   void print_address_on(outputStream* st) const;  // nonvirtual address printing
279 
280   static void set_shared_metaspace_range(void* base, void* top) {
281     _shared_metaspace_base = base;
282     _shared_metaspace_top = top;
283   }
284 
285   static void expand_shared_metaspace_range(void* top) {
286     assert(top >= _shared_metaspace_top, "must be");
287     _shared_metaspace_top = top;
288   }
289 
290   static void* shared_metaspace_base() { return _shared_metaspace_base; }
291   static void* shared_metaspace_top()  { return _shared_metaspace_top;  }
292 
293 #define METASPACE_OBJ_TYPES_DO(f) \
294   f(Class) \
295   f(Symbol) \
296   f(TypeArrayU1) \
297   f(TypeArrayU2) \
298   f(TypeArrayU4) \
299   f(TypeArrayU8) \
300   f(TypeArrayOther) \
301   f(Method) \
302   f(ConstMethod) \
303   f(MethodData) \
304   f(ConstantPool) \
305   f(ConstantPoolCache) \
306   f(Annotations) \
307   f(MethodCounters)
308 
309 #define METASPACE_OBJ_TYPE_DECLARE(name) name ## Type,
310 #define METASPACE_OBJ_TYPE_NAME_CASE(name) case name ## Type: return #name;
311 
312   enum Type {
313     // Types are MetaspaceObj::ClassType, MetaspaceObj::SymbolType, etc
314     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_DECLARE)
315     _number_of_types
316   };
317 
318   static const char * type_name(Type type) {
319     switch(type) {
320     METASPACE_OBJ_TYPES_DO(METASPACE_OBJ_TYPE_NAME_CASE)
321     default:
322       ShouldNotReachHere();
323       return NULL;
324     }
325   }
326 
327   static MetaspaceObj::Type array_type(size_t elem_size) {
328     switch (elem_size) {
329     case 1: return TypeArrayU1Type;
330     case 2: return TypeArrayU2Type;
331     case 4: return TypeArrayU4Type;
332     case 8: return TypeArrayU8Type;
333     default:
334       return TypeArrayOtherType;
335     }
336   }
337 
338   void* operator new(size_t size, ClassLoaderData* loader_data,
339                      size_t word_size,
340                      Type type, Thread* thread) throw();
341                      // can't use TRAPS from this header file.
342   void operator delete(void* p) { ShouldNotCallThis(); }
343 
344   // Declare a *static* method with the same signature in any subclass of MetaspaceObj
345   // that should be read-only by default. See symbol.hpp for an example. This function
346   // is used by the templates in metaspaceClosure.hpp
347   static bool is_read_only_by_default() { return false; }
348 };
349 
350 // Base class for classes that constitute name spaces.
351 
352 class Arena;
353 
354 class AllStatic {
355  public:
356   AllStatic()  { ShouldNotCallThis(); }
357   ~AllStatic() { ShouldNotCallThis(); }
358 };
359 
360 
361 extern char* resource_allocate_bytes(size_t size,
362     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
363 extern char* resource_allocate_bytes(Thread* thread, size_t size,
364     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
365 extern char* resource_reallocate_bytes( char *old, size_t old_size, size_t new_size,
366     AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM);
367 extern void resource_free_bytes( char *old, size_t size );
368 
369 //----------------------------------------------------------------------
370 // Base class for objects allocated in the resource area per default.
371 // Optionally, objects may be allocated on the C heap with
372 // new(ResourceObj::C_HEAP) Foo(...) or in an Arena with new (&arena)
373 // ResourceObj's can be allocated within other objects, but don't use
374 // new or delete (allocation_type is unknown).  If new is used to allocate,
375 // use delete to deallocate.
376 class ResourceObj ALLOCATION_SUPER_CLASS_SPEC {
377  public:
378   enum allocation_type { STACK_OR_EMBEDDED = 0, RESOURCE_AREA, C_HEAP, ARENA, allocation_mask = 0x3 };
379   static void set_allocation_type(address res, allocation_type type) NOT_DEBUG_RETURN;
380 #ifdef ASSERT
381  private:
382   // When this object is allocated on stack the new() operator is not
383   // called but garbage on stack may look like a valid allocation_type.
384   // Store negated 'this' pointer when new() is called to distinguish cases.
385   // Use second array's element for verification value to distinguish garbage.
386   uintptr_t _allocation_t[2];
387   bool is_type_set() const;
388   void initialize_allocation_info();
389  public:
390   allocation_type get_allocation_type() const;
391   bool allocated_on_stack()    const { return get_allocation_type() == STACK_OR_EMBEDDED; }
392   bool allocated_on_res_area() const { return get_allocation_type() == RESOURCE_AREA; }
393   bool allocated_on_C_heap()   const { return get_allocation_type() == C_HEAP; }
394   bool allocated_on_arena()    const { return get_allocation_type() == ARENA; }
395 protected:
396   ResourceObj(); // default constructor
397   ResourceObj(const ResourceObj& r); // default copy constructor
398   ResourceObj& operator=(const ResourceObj& r); // default copy assignment
399   ~ResourceObj();
400 #endif // ASSERT
401 
402  public:
403   void* operator new(size_t size, allocation_type type, MEMFLAGS flags) throw();
404   void* operator new [](size_t size, allocation_type type, MEMFLAGS flags) throw();
405   void* operator new(size_t size, const std::nothrow_t&  nothrow_constant,
406       allocation_type type, MEMFLAGS flags) throw();
407   void* operator new [](size_t size, const std::nothrow_t&  nothrow_constant,
408       allocation_type type, MEMFLAGS flags) throw();
409 
410   void* operator new(size_t size, Arena *arena) throw();
411 
412   void* operator new [](size_t size, Arena *arena) throw();
413 
414   void* operator new(size_t size) throw() {
415       address res = (address)resource_allocate_bytes(size);
416       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)
417       return res;
418   }
419 
420   void* operator new(size_t size, const std::nothrow_t& nothrow_constant) throw() {
421       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);
422       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)
423       return res;
424   }
425 
426   void* operator new [](size_t size) throw() {
427       address res = (address)resource_allocate_bytes(size);
428       DEBUG_ONLY(set_allocation_type(res, RESOURCE_AREA);)
429       return res;
430   }
431 
432   void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw() {
433       address res = (address)resource_allocate_bytes(size, AllocFailStrategy::RETURN_NULL);
434       DEBUG_ONLY(if (res != NULL) set_allocation_type(res, RESOURCE_AREA);)
435       return res;
436   }
437 
438   void  operator delete(void* p);
439   void  operator delete [](void* p);
440 };
441 
442 // One of the following macros must be used when allocating an array
443 // or object to determine whether it should reside in the C heap on in
444 // the resource area.
445 
446 #define NEW_RESOURCE_ARRAY(type, size)\
447   (type*) resource_allocate_bytes((size) * sizeof(type))
448 
449 #define NEW_RESOURCE_ARRAY_RETURN_NULL(type, size)\
450   (type*) resource_allocate_bytes((size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
451 
452 #define NEW_RESOURCE_ARRAY_IN_THREAD(thread, type, size)\
453   (type*) resource_allocate_bytes(thread, (size) * sizeof(type))
454 
455 #define NEW_RESOURCE_ARRAY_IN_THREAD_RETURN_NULL(thread, type, size)\
456   (type*) resource_allocate_bytes(thread, (size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
457 
458 #define REALLOC_RESOURCE_ARRAY(type, old, old_size, new_size)\
459   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type), (new_size) * sizeof(type))
460 
461 #define REALLOC_RESOURCE_ARRAY_RETURN_NULL(type, old, old_size, new_size)\
462   (type*) resource_reallocate_bytes((char*)(old), (old_size) * sizeof(type),\
463                                     (new_size) * sizeof(type), AllocFailStrategy::RETURN_NULL)
464 
465 #define FREE_RESOURCE_ARRAY(type, old, size)\
466   resource_free_bytes((char*)(old), (size) * sizeof(type))
467 
468 #define FREE_FAST(old)\
469     /* nop */
470 
471 #define NEW_RESOURCE_OBJ(type)\
472   NEW_RESOURCE_ARRAY(type, 1)
473 
474 #define NEW_RESOURCE_OBJ_RETURN_NULL(type)\
475   NEW_RESOURCE_ARRAY_RETURN_NULL(type, 1)
476 
477 #define NEW_C_HEAP_ARRAY3(type, size, memflags, pc, allocfail)\
478   (type*) AllocateHeap((size) * sizeof(type), memflags, pc, allocfail)
479 
480 #define NEW_C_HEAP_ARRAY2(type, size, memflags, pc)\
481   (type*) (AllocateHeap((size) * sizeof(type), memflags, pc))
482 
483 #define NEW_C_HEAP_ARRAY(type, size, memflags)\
484   (type*) (AllocateHeap((size) * sizeof(type), memflags))
485 
486 #define NEW_C_HEAP_ARRAY2_RETURN_NULL(type, size, memflags, pc)\
487   NEW_C_HEAP_ARRAY3(type, (size), memflags, pc, AllocFailStrategy::RETURN_NULL)
488 
489 #define NEW_C_HEAP_ARRAY_RETURN_NULL(type, size, memflags)\
490   NEW_C_HEAP_ARRAY3(type, (size), memflags, CURRENT_PC, AllocFailStrategy::RETURN_NULL)
491 
492 #define REALLOC_C_HEAP_ARRAY(type, old, size, memflags)\
493   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags))
494 
495 #define REALLOC_C_HEAP_ARRAY_RETURN_NULL(type, old, size, memflags)\
496   (type*) (ReallocateHeap((char*)(old), (size) * sizeof(type), memflags, AllocFailStrategy::RETURN_NULL))
497 
498 #define FREE_C_HEAP_ARRAY(type, old) \
499   FreeHeap((char*)(old))
500 
501 // allocate type in heap without calling ctor
502 #define NEW_C_HEAP_OBJ(type, memflags)\
503   NEW_C_HEAP_ARRAY(type, 1, memflags)
504 
505 #define NEW_C_HEAP_OBJ_RETURN_NULL(type, memflags)\
506   NEW_C_HEAP_ARRAY_RETURN_NULL(type, 1, memflags)
507 
508 // deallocate obj of type in heap without calling dtor
509 #define FREE_C_HEAP_OBJ(objname)\
510   FreeHeap((char*)objname);
511 
512 
513 //------------------------------ReallocMark---------------------------------
514 // Code which uses REALLOC_RESOURCE_ARRAY should check an associated
515 // ReallocMark, which is declared in the same scope as the reallocated
516 // pointer.  Any operation that could __potentially__ cause a reallocation
517 // should check the ReallocMark.
518 class ReallocMark: public StackObj {
519 protected:
520   NOT_PRODUCT(int _nesting;)
521 
522 public:
523   ReallocMark()   PRODUCT_RETURN;
524   void check()    PRODUCT_RETURN;
525 };
526 
527 // Helper class to allocate arrays that may become large.
528 // Uses the OS malloc for allocations smaller than ArrayAllocatorMallocLimit
529 // and uses mapped memory for larger allocations.
530 // Most OS mallocs do something similar but Solaris malloc does not revert
531 // to mapped memory for large allocations. By default ArrayAllocatorMallocLimit
532 // is set so that we always use malloc except for Solaris where we set the
533 // limit to get mapped memory.
534 template <class E>
535 class ArrayAllocator : public AllStatic {
536  private:
537   static bool should_use_malloc(size_t length);
538 
539   static E* allocate_malloc(size_t length, MEMFLAGS flags);
540   static E* allocate_mmap(size_t length, MEMFLAGS flags);
541 
542   static void free_malloc(E* addr, size_t length);
543   static void free_mmap(E* addr, size_t length);
544 
545  public:
546   static E* allocate(size_t length, MEMFLAGS flags);
547   static E* reallocate(E* old_addr, size_t old_length, size_t new_length, MEMFLAGS flags);
548   static void free(E* addr, size_t length);
549 };
550 
551 // Uses mmaped memory for all allocations. All allocations are initially
552 // zero-filled. No pre-touching.
553 template <class E>
554 class MmapArrayAllocator : public AllStatic {
555  private:
556   static size_t size_for(size_t length);
557 
558  public:
559   static E* allocate_or_null(size_t length, MEMFLAGS flags);
560   static E* allocate(size_t length, MEMFLAGS flags);
561   static void free(E* addr, size_t length);
562 };
563 
564 // Uses malloc:ed memory for all allocations.
565 template <class E>
566 class MallocArrayAllocator : public AllStatic {
567  public:
568   static size_t size_for(size_t length);
569 
570   static E* allocate(size_t length, MEMFLAGS flags);
571   static void free(E* addr);
572 };
573 
574 #endif // SHARE_MEMORY_ALLOCATION_HPP