1 /*
 2  * Copyright (c) 2011, 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
 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 #include "cds/cdsConfig.hpp"
26 #include "cds/serializeClosure.hpp"
27 #include "classfile/javaClasses.inline.hpp"
28 #include "gc/shared/collectedHeap.inline.hpp"
29 #include "memory/iterator.inline.hpp"
30 #include "memory/oopFactory.hpp"
31 #include "memory/universe.hpp"
32 #include "oops/instanceKlass.hpp"
33 #include "oops/instanceMirrorKlass.hpp"
34 #include "oops/instanceOop.hpp"
35 #include "oops/oop.inline.hpp"
36 #include "oops/symbol.hpp"
37 #include "runtime/handles.inline.hpp"
38 #include "utilities/macros.hpp"
39 
40 int InstanceMirrorKlass::_offset_of_static_fields = 0;
41 
42 InstanceMirrorKlass::InstanceMirrorKlass() {
43   assert(CDSConfig::is_dumping_static_archive() || CDSConfig::is_using_archive(), "only for CDS");
44 }
45 
46 size_t InstanceMirrorKlass::instance_size(Klass* k) {
47   if (k != nullptr && k->is_instance_klass()) {
48     return align_object_size(size_helper() + InstanceKlass::cast(k)->static_field_size());
49   }
50   return size_helper();
51 }
52 
53 instanceOop InstanceMirrorKlass::allocate_instance(Klass* k, bool extend, TRAPS) {
54   // Query before forming handle.
55   size_t base_size = instance_size(k);
56   size_t size = base_size;
57   if (extend && UseCompactObjectHeaders) {
58     size = align_object_size(size + 1);
59   }
60   assert(base_size > 0, "base object size must be non-zero: %zu", base_size);
61 
62   // Since mirrors can be variable sized because of the static fields, store
63   // the size in the mirror itself.
64   instanceOop obj = (instanceOop)Universe::heap()->class_allocate(this, size, base_size, THREAD);
65   if (extend && UseCompactObjectHeaders) {
66     obj->set_mark(obj->mark().set_not_hashed_expanded());
67     assert(expand_for_hash(obj, obj->mark()), "must expand for hash");
68   }
69   return obj;
70 }
71 
72 size_t InstanceMirrorKlass::oop_size(oop obj, markWord mark) const {
73   return java_lang_Class::oop_size(obj);
74 }
75 
76 int InstanceMirrorKlass::compute_static_oop_field_count(oop obj) {
77   Klass* k = java_lang_Class::as_Klass(obj);
78   if (k != nullptr && k->is_instance_klass()) {
79     return InstanceKlass::cast(k)->static_oop_field_count();
80   }
81   return 0;
82 }
83 
84 int InstanceMirrorKlass::hash_offset_in_bytes(oop obj, markWord m) const {
85   assert(UseCompactObjectHeaders, "only with compact i-hash");
86   // TODO: There may be gaps that we could use, e.g. in the fields of Class,
87   // between the fields of Class and the static fields or in or at the end of
88   // the static fields block.
89   // When implementing any change here, make sure that allocate_instance()
90   // and corresponding code in InstanceMirrorKlass.java are in sync.
91   return checked_cast<int>(obj->base_size_given_klass(m, this) * BytesPerWord);
92 }
93 
94 #if INCLUDE_CDS
95 void InstanceMirrorKlass::serialize_offsets(SerializeClosure* f) {
96   f->do_int(&_offset_of_static_fields);
97 }
98 #endif