1/*
2 * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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
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23 */
24
25#ifndef SHARE_GC_SHARED_MEMALLOCATOR_HPP
26#define SHARE_GC_SHARED_MEMALLOCATOR_HPP
27
28#include "gc/shared/collectedHeap.hpp"
29#include "memory/memRegion.hpp"
30#include "oops/oopsHierarchy.hpp"
31#include "utilities/exceptions.hpp"
32#include "utilities/macros.hpp"
33
34// These fascilities are used for allocating, and initializing newly allocated objects.
35
36class MemAllocator: StackObj {
37protected:
38 class Allocation;
39
40 Thread* const _thread;
41 Klass* const _klass;
42 const size_t _word_size;
43
44private:
45 // Allocate from the current thread's TLAB, with broken-out slow path.
46 HeapWord* allocate_inside_tlab(Allocation& allocation) const;
47 HeapWord* allocate_inside_tlab_slow(Allocation& allocation) const;
48 HeapWord* allocate_outside_tlab(Allocation& allocation) const;
49
50protected:
51 MemAllocator(Klass* klass, size_t word_size, Thread* thread)
52 : _thread(thread),
53 _klass(klass),
54 _word_size(word_size)
55 { }
56
57 // This function clears the memory of the object
58 void mem_clear(HeapWord* mem) const;
59 // This finish constructing an oop by installing the mark word and the Klass* pointer
60 // last. At the point when the Klass pointer is initialized, this is a constructed object
61 // that must be parseable as an oop by concurrent collectors.
62 oop finish(HeapWord* mem) const;
63
64 // Raw memory allocation. This may or may not use TLAB allocations to satisfy the
65 // allocation. A GC implementation may override this function to satisfy the allocation
66 // in any way. But the default is to try a TLAB allocation, and otherwise perform
67 // mem_allocate.
68 virtual HeapWord* mem_allocate(Allocation& allocation) const;
69
70 virtual MemRegion obj_memory_range(oop obj) const {
71 return MemRegion((HeapWord*)obj, _word_size);
72 }
73
74public:
75 oop allocate() const;
76 virtual oop initialize(HeapWord* mem) const = 0;
77};
78
79class ObjAllocator: public MemAllocator {
80public:
81 ObjAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())
82 : MemAllocator(klass, word_size, thread) {}
83 virtual oop initialize(HeapWord* mem) const;
84};
85
86class ObjArrayAllocator: public MemAllocator {
87 const int _length;
88 const bool _do_zero;
89protected:
90 virtual MemRegion obj_memory_range(oop obj) const;
91
92public:
93 ObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero,
94 Thread* thread = Thread::current())
95 : MemAllocator(klass, word_size, thread),
96 _length(length),
97 _do_zero(do_zero) {}
98 virtual oop initialize(HeapWord* mem) const;
99};
100
101class ClassAllocator: public MemAllocator {
102public:
103 ClassAllocator(Klass* klass, size_t word_size, Thread* thread = Thread::current())
104 : MemAllocator(klass, word_size, thread) {}
105 virtual oop initialize(HeapWord* mem) const;
106};
107
108#endif // SHARE_GC_SHARED_MEMALLOCATOR_HPP
109