1 /*
2 * Copyright (c) 1998, 2018, 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 class AllocFailStrategy {
29 public:
30 enum AllocFailEnum { EXIT_OOM, RETURN_NULL };
31 };
32 typedef AllocFailStrategy::AllocFailEnum AllocFailType;
33
34 void* AllocateHeap(size_t size, AllocFailType alloc_fail_mode = AllocFailStrategy::EXIT_OOM);
35
36 // All classes in adlc may be derived
37 // from one of the following allocation classes:
38 //
39 // For objects allocated in the C-heap (managed by: malloc & free).
40 // - CHeapObj
41 //
42 // For classes used as name spaces.
43 // - AllStatic
44 //
45
46 class CHeapObj {
47 public:
48 void* operator new(size_t size) throw();
49 void operator delete(void* p);
50 void* new_array(size_t size);
51 };
52
53 // Base class for classes that constitute name spaces.
54
55 class AllStatic {
56 public:
57 void* operator new(size_t size) throw();
58 void operator delete(void* p);
59 };
60
61
62 //------------------------------Chunk------------------------------------------
63 // Linked list of raw memory chunks
64 class Chunk: public CHeapObj {
65 private:
66 // This ordinary operator delete is needed even though not used, so the
67 // below two-argument operator delete will be treated as a placement
68 // delete rather than an ordinary sized delete; see C++14 3.7.4.2/p2.
69 void operator delete(void* p);
70 public:
71 void* operator new(size_t size, size_t length) throw();
72 void operator delete(void* p, size_t length);
73 Chunk(size_t length);
74
75 enum {
76 init_size = 1*1024, // Size of first chunk
77 size = 32*1024 // Default size of an Arena chunk (following the first)
78 };
79 Chunk* _next; // Next Chunk in list
80 size_t _len; // Size of this Chunk
81
82 void chop(); // Chop this chunk
83 void next_chop(); // Chop next chunk
84
85 // Boundaries of data area (possibly unused)
86 char* bottom() const { return ((char*) this) + sizeof(Chunk); }
87 char* top() const { return bottom() + _len; }
88 };
89
90
91 //------------------------------Arena------------------------------------------
92 // Fast allocation of memory
93 class Arena: public CHeapObj {
94 protected:
95 friend class ResourceMark;
96 friend class HandleMark;
97 friend class NoHandleMark;
98 Chunk *_first; // First chunk
99 Chunk *_chunk; // current chunk
100 char *_hwm, *_max; // High water mark and max in current chunk
101 void* grow(size_t x); // Get a new Chunk of at least size x
102 size_t _size_in_bytes; // Size of arena (used for memory usage tracing)
103 public:
104 Arena();
105 Arena(size_t init_size);
106 Arena(Arena *old);
107 ~Arena() { _first->chop(); }
108 char* hwm() const { return _hwm; }
109
110 // Fast allocate in the arena. Common case is: pointer test + increment.
111 void* Amalloc(size_t x) {
112 #ifdef _LP64
113 x = (x + (8-1)) & ((unsigned)(-8));
114 #else
115 x = (x + (4-1)) & ((unsigned)(-4));
116 #endif
117 if (_hwm + x > _max) {
118 return grow(x);
119 } else {
120 char *old = _hwm;
121 _hwm += x;
122 return old;
123 }
124 }
125 // Further assume size is padded out to words
126 // Warning: in LP64, Amalloc_4 is really Amalloc_8
127 void *Amalloc_4(size_t x) {
128 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
129 if (_hwm + x > _max) {
130 return grow(x);
131 } else {
132 char *old = _hwm;
133 _hwm += x;
134 return old;
135 }
136 }
137
138 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
139 void Afree(void *ptr, size_t size) {
140 if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
141 }
142
143 void *Acalloc( size_t items, size_t x );
144 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size );
145
146 // Reset this Arena to empty, and return this Arenas guts in a new Arena.
147 Arena *reset(void);
148
149 // Determine if pointer belongs to this Arena or not.
150 bool contains( const void *ptr ) const;
151
152 // Total of all chunks in use (not thread-safe)
153 size_t used() const;
154
155 // Total # of bytes used
156 size_t size_in_bytes() const { return _size_in_bytes; }
157 void set_size_in_bytes(size_t size) { _size_in_bytes = size; }
158 };
159
160 #endif // SHARE_VM_ADLC_ARENA_HPP