1 /*
2 * Copyright (c) 1997, 2025, 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
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
24
25 #ifndef SHARE_OOPS_OBJARRAYOOP_HPP
26 #define SHARE_OOPS_OBJARRAYOOP_HPP
27
28 #include "oops/arrayOop.hpp"
29 #include "utilities/align.hpp"
30
31 #include <type_traits>
32
33 class Klass;
34
35 // An objArrayOop is an array containing oops.
36 // Evaluating "String arg[10]" will create an objArrayOop.
37
38 class objArrayOopDesc : public arrayOopDesc {
39 friend class ArchiveHeapWriter;
40 friend class ObjArrayKlass;
41 friend class Runtime1;
42 friend class psPromotionManager;
43 friend class CSetMarkWordClosure;
44 friend class Continuation;
45 template <typename T>
46 friend class RawOopWriter;
47 friend class AOTMapLogger;
48
49 template <class T> T* obj_at_addr(int index) const;
50
51 template <class T>
52 static ptrdiff_t obj_at_offset(int index) {
53 return base_offset_in_bytes() + sizeof(T) * index;
54 }
55
56 public:
57 // Returns the offset of the first element.
58 static int base_offset_in_bytes() {
59 return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
60 }
61
62 // base is the address following the header.
63 HeapWord* base() const;
64
65 // Accessing
66 oop obj_at(int index) const;
67
68 void obj_at_put(int index, oop value);
69
70 oop replace_if_null(int index, oop exchange_value);
71
72 // Sizing
73 size_t object_size() { return object_size(length()); }
74
75 static size_t object_size(int length) {
76 // This returns the object size in HeapWords.
77 size_t asz = (size_t)length * heapOopSize;
78 size_t size_words = heap_word_size(base_offset_in_bytes() + asz);
79 size_t osz = align_object_size(size_words);
80 assert(osz < max_jint, "no overflow");
81 return osz;
82 }
83
84 Klass* element_klass();
85
86 public:
87 // special iterators for index ranges, returns size of object
88 template <typename OopClosureType>
89 void oop_iterate_range(OopClosureType* blk, int start, int end);
90 };
91
92 // See similar requirement for oopDesc.
93 static_assert(std::is_trivially_default_constructible<objArrayOopDesc>::value, "required");
94
95 #endif // SHARE_OOPS_OBJARRAYOOP_HPP