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 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