1 /* 2 * Copyright (c) 1998, 2010, 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_VM_ADLC_ARENA_HPP 26 #define SHARE_VM_ADLC_ARENA_HPP 27 28 // All classes in the virtual machine must be subclassed 29 // by one of the following allocation classes: 30 // 31 // 32 // For objects allocated in the C-heap (managed by: free & malloc). 33 // - CHeapObj 34 // 35 // 36 // For embedded objects. 37 // - ValueObj 38 // 39 // For classes used as name spaces. 40 // - AllStatic 41 // 42 43 class CHeapObj { 44 public: 45 void* operator new(size_t size); 46 void operator delete(void* p); 47 void* new_array(size_t size); 48 }; 49 50 51 // Base class for objects used as value objects. 52 // Calling new or delete will result in fatal error. 53 54 class ValueObj { 55 public: 56 void* operator new(size_t size); 57 void operator delete(void* p); 58 }; 59 60 // Base class for classes that constitute name spaces. 61 62 class AllStatic { 63 public: 64 void* operator new(size_t size); 65 void operator delete(void* p); 66 }; 67 68 69 //------------------------------Chunk------------------------------------------ 70 // Linked list of raw memory chunks 71 class Chunk: public CHeapObj { 72 public: 73 void* operator new(size_t size, size_t length); 74 void operator delete(void* p, size_t length); 75 Chunk(size_t length); 76 77 enum { 78 init_size = 1*1024, // Size of first chunk 79 size = 32*1024 // Default size of an Arena chunk (following the first) 80 }; 81 Chunk* _next; // Next Chunk in list 82 size_t _len; // Size of this Chunk 83 84 void chop(); // Chop this chunk 85 void next_chop(); // Chop next chunk 86 87 // Boundaries of data area (possibly unused) 88 char* bottom() const { return ((char*) this) + sizeof(Chunk); } 89 char* top() const { return bottom() + _len; } 90 }; 91 92 93 //------------------------------Arena------------------------------------------ 94 // Fast allocation of memory 95 class Arena: public CHeapObj { 96 protected: 97 friend class ResourceMark; 98 friend class HandleMark; 99 friend class NoHandleMark; 100 Chunk *_first; // First chunk 101 Chunk *_chunk; // current chunk 102 char *_hwm, *_max; // High water mark and max in current chunk 103 void* grow(size_t x); // Get a new Chunk of at least size x 104 size_t _size_in_bytes; // Size of arena (used for memory usage tracing) 105 public: 106 Arena(); 107 Arena(size_t init_size); 108 Arena(Arena *old); 109 ~Arena() { _first->chop(); } 110 char* hwm() const { return _hwm; } 111 112 // Fast allocate in the arena. Common case is: pointer test + increment. 113 void* Amalloc(size_t x) { 114 #ifdef _LP64 115 x = (x + (8-1)) & ((unsigned)(-8)); 116 #else 117 x = (x + (4-1)) & ((unsigned)(-4)); 118 #endif 119 if (_hwm + x > _max) { 120 return grow(x); 121 } else { 122 char *old = _hwm; 123 _hwm += x; 124 return old; 125 } 126 } 127 // Further assume size is padded out to words 128 // Warning: in LP64, Amalloc_4 is really Amalloc_8 129 void *Amalloc_4(size_t x) { 130 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" ); 131 if (_hwm + x > _max) { 132 return grow(x); 133 } else { 134 char *old = _hwm; 135 _hwm += x; 136 return old; 137 } 138 } 139 140 // Fast delete in area. Common case is: NOP (except for storage reclaimed) 141 void Afree(void *ptr, size_t size) { 142 if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr; 143 } 144 145 void *Acalloc( size_t items, size_t x ); 146 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size ); 147 148 // Reset this Arena to empty, and return this Arenas guts in a new Arena. 149 Arena *reset(void); 150 151 // Determine if pointer belongs to this Arena or not. 152 bool contains( const void *ptr ) const; 153 154 // Total of all chunks in use (not thread-safe) 155 size_t used() const; 156 157 // Total # of bytes used 158 size_t size_in_bytes() const { return _size_in_bytes; } 159 void set_size_in_bytes(size_t size) { _size_in_bytes = size; } 160 }; 161 162 #endif // SHARE_VM_ADLC_ARENA_HPP