1 /*
2 * Copyright (c) 1998, 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 */
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) throw();
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) throw();
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) throw();
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) throw();
74 // Usual (non-placement) deallocation function to allow placement delete use size_t
75 // See 3.7.4.2 [basic.stc.dynamic.deallocation] paragraph 2.
76 void operator delete(void* p);
77 void operator delete(void* p, size_t length);
78 Chunk(size_t length);
79
80 enum {
81 init_size = 1*1024, // Size of first chunk
82 size = 32*1024 // Default size of an Arena chunk (following the first)
83 };
84 Chunk* _next; // Next Chunk in list
85 size_t _len; // Size of this Chunk
86
87 void chop(); // Chop this chunk
88 void next_chop(); // Chop next chunk
89
90 // Boundaries of data area (possibly unused)
91 char* bottom() const { return ((char*) this) + sizeof(Chunk); }
92 char* top() const { return bottom() + _len; }
93 };
94
95
96 //------------------------------Arena------------------------------------------
97 // Fast allocation of memory
98 class Arena: public CHeapObj {
99 protected:
100 friend class ResourceMark;
101 friend class HandleMark;
102 friend class NoHandleMark;
103 Chunk *_first; // First chunk
104 Chunk *_chunk; // current chunk
105 char *_hwm, *_max; // High water mark and max in current chunk
106 void* grow(size_t x); // Get a new Chunk of at least size x
107 size_t _size_in_bytes; // Size of arena (used for memory usage tracing)
108 public:
109 Arena();
110 Arena(size_t init_size);
111 Arena(Arena *old);
112 ~Arena() { _first->chop(); }
113 char* hwm() const { return _hwm; }
114
115 // Fast allocate in the arena. Common case is: pointer test + increment.
116 void* Amalloc(size_t x) {
117 #ifdef _LP64
118 x = (x + (8-1)) & ((unsigned)(-8));
119 #else
120 x = (x + (4-1)) & ((unsigned)(-4));
121 #endif
122 if (_hwm + x > _max) {
123 return grow(x);
124 } else {
125 char *old = _hwm;
126 _hwm += x;
127 return old;
128 }
129 }
130 // Further assume size is padded out to words
131 // Warning: in LP64, Amalloc_4 is really Amalloc_8
132 void *Amalloc_4(size_t x) {
133 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
134 if (_hwm + x > _max) {
135 return grow(x);
136 } else {
137 char *old = _hwm;
138 _hwm += x;
139 return old;
140 }
141 }
142
143 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
144 void Afree(void *ptr, size_t size) {
145 if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
146 }
147
148 void *Acalloc( size_t items, size_t x );
149 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size );
150
151 // Reset this Arena to empty, and return this Arenas guts in a new Arena.
152 Arena *reset(void);
153
154 // Determine if pointer belongs to this Arena or not.
155 bool contains( const void *ptr ) const;
156
157 // Total of all chunks in use (not thread-safe)
158 size_t used() const;
159
160 // Total # of bytes used
161 size_t size_in_bytes() const { return _size_in_bytes; }
162 void set_size_in_bytes(size_t size) { _size_in_bytes = size; }
163 };
164
165 #endif // SHARE_VM_ADLC_ARENA_HPP