1 /*
 2  * Copyright (c) 2005, 2021, 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
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24 
25 #ifndef SHARE_OOPS_KLASS_INLINE_HPP
26 #define SHARE_OOPS_KLASS_INLINE_HPP
27 
28 #include "oops/klass.hpp"
29 
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "oops/klassVtable.hpp"
32 #include "oops/markWord.hpp"
33 
34 // This loads the klass's holder as a phantom. This is useful when a weak Klass
35 // pointer has been "peeked" and then must be kept alive before it may
36 // be used safely.  All uses of klass_holder need to apply the appropriate barriers,
37 // except during GC.
38 inline oop Klass::klass_holder() const {
39   return class_loader_data()->holder_phantom();
40 }
41 
42 inline bool Klass::is_non_strong_hidden() const {
43   return access_flags().is_hidden_class() &&
44          class_loader_data()->has_class_mirror_holder();
45 }
46 
47 // Iff the class loader (or mirror for non-strong hidden classes) is alive the
48 // Klass is considered alive. This is safe to call before the CLD is marked as
49 // unloading, and hence during concurrent class unloading.
50 inline bool Klass::is_loader_alive() const {
51   return class_loader_data()->is_alive();
52 }
53 
54 inline void Klass::set_prototype_header(markWord header) {
55   assert(UseCompactObjectHeaders || !header.has_bias_pattern() || is_instance_klass(), "biased locking currently only supported for Java instances");
56   _prototype_header = header;
57 }
58 
59 inline oop Klass::java_mirror() const {
60   return _java_mirror.resolve();
61 }
62 
63 inline klassVtable Klass::vtable() const {
64   return klassVtable(const_cast<Klass*>(this), start_of_vtable(), vtable_length() / vtableEntry::size());
65 }
66 
67 inline oop Klass::class_loader() const {
68   return class_loader_data()->class_loader();
69 }
70 
71 inline vtableEntry* Klass::start_of_vtable() const {
72   return (vtableEntry*) ((address)this + in_bytes(vtable_start_offset()));
73 }
74 
75 inline ByteSize Klass::vtable_start_offset() {
76   return in_ByteSize(InstanceKlass::header_size() * wordSize);
77 }
78 
79 #endif // SHARE_OOPS_KLASS_INLINE_HPP