1 /*
2 * Copyright (c) 1998, 2019, 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_ADLC_ARENA_HPP
26 #define SHARE_ADLC_ARENA_HPP
27
28 void* AllocateHeap(size_t size);
29 void* ReAllocateHeap(void* old_ptr, size_t size);
30
31 // All classes in adlc may be derived
32 // from one of the following allocation classes:
33 //
34 // For objects allocated in the C-heap (managed by: malloc & free).
35 // - CHeapObj
36 //
37 // For classes used as name spaces.
38 // - AllStatic
39 //
40
41 class CHeapObj {
42 public:
43 void* operator new(size_t size) throw();
44 void operator delete(void* p);
45 void* new_array(size_t size);
46 };
47
48 // Base class for classes that constitute name spaces.
49
50 class AllStatic {
51 public:
52 void* operator new(size_t size) throw();
53 void operator delete(void* p);
54 };
55
56
57 //------------------------------Chunk------------------------------------------
58 // Linked list of raw memory chunks
59 class Chunk: public CHeapObj {
60 private:
61 // This ordinary operator delete is needed even though not used, so the
62 // below two-argument operator delete will be treated as a placement
63 // delete rather than an ordinary sized delete; see C++14 3.7.4.2/p2.
64 void operator delete(void* p);
65 public:
66 void* operator new(size_t size, size_t length) throw();
67 void operator delete(void* p, size_t length);
68 Chunk(size_t length);
69
70 enum {
71 init_size = 1*1024, // Size of first chunk
72 size = 32*1024 // Default size of an Arena chunk (following the first)
73 };
74 Chunk* _next; // Next Chunk in list
75 size_t _len; // Size of this Chunk
76
77 void chop(); // Chop this chunk
78 void next_chop(); // Chop next chunk
79
80 // Boundaries of data area (possibly unused)
81 char* bottom() const { return ((char*) this) + sizeof(Chunk); }
82 char* top() const { return bottom() + _len; }
83 };
84
85
86 //------------------------------Arena------------------------------------------
87 // Fast allocation of memory
88 class Arena: public CHeapObj {
89 protected:
90 friend class ResourceMark;
91 friend class HandleMark;
92 friend class NoHandleMark;
93 Chunk *_first; // First chunk
94 Chunk *_chunk; // current chunk
95 char *_hwm, *_max; // High water mark and max in current chunk
96 void* grow(size_t x); // Get a new Chunk of at least size x
97 size_t _size_in_bytes; // Size of arena (used for memory usage tracing)
98 public:
99 Arena();
100 Arena(size_t init_size);
101 Arena(Arena *old);
102 ~Arena() { _first->chop(); }
103 char* hwm() const { return _hwm; }
104
105 // Fast allocate in the arena. Common case is: pointer test + increment.
106 void* Amalloc(size_t x) {
107 #ifdef _LP64
108 x = (x + (8-1)) & ((unsigned)(-8));
109 #else
110 x = (x + (4-1)) & ((unsigned)(-4));
111 #endif
112 if (_hwm + x > _max) {
113 return grow(x);
114 } else {
115 char *old = _hwm;
116 _hwm += x;
117 return old;
118 }
119 }
120 // Further assume size is padded out to words
121 // Warning: in LP64, Amalloc_4 is really Amalloc_8
122 void *Amalloc_4(size_t x) {
123 assert( (x&(sizeof(char*)-1)) == 0, "misaligned size" );
124 if (_hwm + x > _max) {
125 return grow(x);
126 } else {
127 char *old = _hwm;
128 _hwm += x;
129 return old;
130 }
131 }
132
133 // Fast delete in area. Common case is: NOP (except for storage reclaimed)
134 void Afree(void *ptr, size_t size) {
135 if (((char*)ptr) + size == _hwm) _hwm = (char*)ptr;
136 }
137
138 void *Acalloc( size_t items, size_t x );
139 void *Arealloc( void *old_ptr, size_t old_size, size_t new_size );
140
141 // Reset this Arena to empty, and return this Arenas guts in a new Arena.
142 Arena *reset(void);
143
144 // Determine if pointer belongs to this Arena or not.
145 bool contains( const void *ptr ) const;
146
147 // Total of all chunks in use (not thread-safe)
148 size_t used() const;
149
150 // Total # of bytes used
151 size_t size_in_bytes() const { return _size_in_bytes; }
152 void set_size_in_bytes(size_t size) { _size_in_bytes = size; }
153 };
154
155 #endif // SHARE_ADLC_ARENA_HPP