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.
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23 */
24
25 #ifndef SHARE_VM_ADLC_ARENA_HPP
26 #define SHARE_VM_ADLC_ARENA_HPP
27
28 void* AllocateHeap(size_t size);
29
30 // All classes in adlc may be derived
31 // from one of the following allocation classes:
32 //
33 // For objects allocated in the C-heap (managed by: malloc & free).
34 // - CHeapObj
35 //
36 // For classes used as name spaces.
37 // - AllStatic
38 //
39
40 class CHeapObj {
41 public:
42 void* operator new(size_t size) throw();
43 void operator delete(void* p);
44 void* new_array(size_t size);
45 };
46
47 // Base class for classes that constitute name spaces.
48
49 class AllStatic {
50 public:
51 void* operator new(size_t size) throw();
52 void operator delete(void* p);
53 };
54
55
56 //------------------------------Chunk------------------------------------------
57 // Linked list of raw memory chunks
58 class Chunk: public CHeapObj {
59 private:
60 // This ordinary operator delete is needed even though not used, so the
61 // below two-argument operator delete will be treated as a placement
62 // delete rather than an ordinary sized delete; see C++14 3.7.4.2/p2.
63 void operator delete(void* p);
64 public:
65 void* operator new(size_t size, size_t length) throw();
66 void operator delete(void* p, size_t length);
67 Chunk(size_t length);
68
69 enum {
70 init_size = 1*1024, // Size of first chunk
71 size = 32*1024 // Default size of an Arena chunk (following the first)
72 };
73 Chunk* _next; // Next Chunk in list
74 size_t _len; // Size of this Chunk
75
76 void chop(); // Chop this chunk
77 void next_chop(); // Chop next chunk
78
79 // Boundaries of data area (possibly unused)
80 char* bottom() const { return ((char*) this) + sizeof(Chunk); }
81 char* top() const { return bottom() + _len; }
82 };
83
84
85 //------------------------------Arena------------------------------------------
86 // Fast allocation of memory
87 class Arena: public CHeapObj {
88 protected:
89 friend class ResourceMark;
90 friend class HandleMark;
91 friend class NoHandleMark;
92 Chunk *_first; // First chunk
93 Chunk *_chunk; // current chunk
94 char *_hwm, *_max; // High water mark and max in current chunk
95 void* grow(size_t x); // Get a new Chunk of at least size x
96 size_t _size_in_bytes; // Size of arena (used for memory usage tracing)
97 public:
98 Arena();
99 Arena(size_t init_size);
100 Arena(Arena *old);
101 ~Arena() { _first->chop(); }
102 char* hwm() const { return _hwm; }
103
104 // Fast allocate in the arena. Common case is: pointer test + increment.
105 void* Amalloc(size_t x) {
106 #ifdef _LP64
107 x = (x + (8-1)) & ((unsigned)(-8));
108 #else
109 x = (x + (4-1)) & ((unsigned)(-4));
110 #endif
111 if (_hwm + x > _max) {
112 return grow(x);
113 } else {
114 char *old = _hwm;
115 _hwm += x;
116 return old;
117 }
118 }
119 // Further assume size is padded out to words
120 // Warning: in LP64, Amalloc_4 is really Amalloc_8
121 void *Amalloc_4(size_t x) {
122 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
123 if (_hwm + x > _max) {
124 return grow(x);
125 } else {
126 char *old = _hwm;
127 _hwm += x;
128 return old;
129 }
130 }
131
132 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
133 void Afree(void *ptr, size_t size) {
134 if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
135 }
136
137 void *Acalloc( size_t items, size_t x );
138 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size );
139
140 // Reset this Arena to empty, and return this Arenas guts in a new Arena.
141 Arena *reset(void);
142
143 // Determine if pointer belongs to this Arena or not.
144 bool contains( const void *ptr ) const;
145
146 // Total of all chunks in use (not thread-safe)
147 size_t used() const;
148
149 // Total # of bytes used
150 size_t size_in_bytes() const { return _size_in_bytes; }
151 void set_size_in_bytes(size_t size) { _size_in_bytes = size; }
152 };
153
154 #endif // SHARE_VM_ADLC_ARENA_HPP