1 /*
2 * Copyright (c) 2023, 2024, 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.
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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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23 */
24
25 #ifndef SHARE_OOPS_INSTANCEKLASSFLAGS_HPP
26 #define SHARE_OOPS_INSTANCEKLASSFLAGS_HPP
27
28 #include "runtime/atomic.hpp"
29
30 class ClassLoaderData;
31
32 // The InstanceKlassFlags class contains the parse-time and writeable flags associated with
33 // an InstanceKlass, and their associated accessors.
34 // _flags are parse-time and constant in the InstanceKlass after that. _status are set at runtime and
35 // require atomic access.
36 // These flags are JVM internal and not part of the AccessFlags classfile specification.
37
38 class InstanceKlassFlags {
39 friend class VMStructs;
40 friend class JVMCIVMStructs;
41
42 #define IK_FLAGS_DO(flag) \
43 flag(rewritten , 1 << 0) /* methods rewritten. */ \
44 flag(has_nonstatic_fields , 1 << 1) /* for sizing with UseCompressedOops */ \
45 flag(should_verify_class , 1 << 2) /* allow caching of preverification */ \
46 flag(is_contended , 1 << 3) /* marked with contended annotation */ \
47 flag(has_nonstatic_concrete_methods , 1 << 4) /* class/superclass/implemented interfaces has non-static, concrete methods */ \
48 flag(declares_nonstatic_concrete_methods, 1 << 5) /* directly declares non-static, concrete methods */ \
49 flag(shared_loading_failed , 1 << 6) /* class has been loaded from shared archive */ \
50 flag(is_shared_boot_class , 1 << 7) /* defining class loader is boot class loader */ \
51 flag(is_shared_platform_class , 1 << 8) /* defining class loader is platform class loader */ \
52 flag(is_shared_app_class , 1 << 9) /* defining class loader is app class loader */ \
53 flag(has_contended_annotations , 1 << 10) /* has @Contended annotation */ \
54 flag(has_localvariable_table , 1 << 11) /* has localvariable information */ \
55 flag(has_miranda_methods , 1 << 12) /* True if this class has miranda methods in it's vtable */ \
56 flag(has_final_method , 1 << 13) /* True if klass has final method */ \
57 flag(has_inline_type_fields , 1 << 14) /* has inline fields and related embedded section is not empty */ \
58 flag(is_empty_inline_type , 1 << 15) /* empty inline type (*) */ \
59 flag(is_naturally_atomic , 1 << 16) /* loaded/stored in one instruction*/ \
60 flag(must_be_atomic , 1 << 17) /* doesn't allow tearing */ \
61 flag(has_loosely_consistent_annotation , 1 << 18) /* the class has the LooselyConsistentValue annotation WARNING: it doesn't automatically mean that the class allows tearing */ \
62 /* end of list */
63
64 /* (*) An inline type is considered empty if it contains no non-static fields or
65 if it contains only empty inline fields. Note that JITs have a slightly different
66 definition: empty inline fields must be flat otherwise the container won't
67 be considered empty */
68
69 #define IK_FLAGS_ENUM_NAME(name, value) _misc_##name = value,
70 enum {
71 IK_FLAGS_DO(IK_FLAGS_ENUM_NAME)
72 };
73 #undef IK_FLAGS_ENUM_NAME
74
75 #define IK_STATUS_DO(status) \
76 status(is_being_redefined , 1 << 0) /* True if the klass is being redefined */ \
77 status(has_resolved_methods , 1 << 1) /* True if the klass has resolved MethodHandle methods */ \
78 status(has_been_redefined , 1 << 2) /* class has been redefined */ \
79 status(is_scratch_class , 1 << 3) /* class is the redefined scratch class */ \
80 status(is_marked_dependent , 1 << 4) /* class is the redefined scratch class */ \
81 /* end of list */
82
83 #define IK_STATUS_ENUM_NAME(name, value) _misc_##name = value,
84 enum {
85 IK_STATUS_DO(IK_STATUS_ENUM_NAME)
86 };
87 #undef IK_STATUS_ENUM_NAME
88
89 u2 shared_loader_type_bits() const {
90 return _misc_is_shared_boot_class|_misc_is_shared_platform_class|_misc_is_shared_app_class;
91 }
92
93 // These flags are write-once before the class is published and then read-only so don't require atomic updates.
94 u4 _flags;
95
96 // These flags are written during execution so require atomic stores
97 u1 _status;
98
99 public:
100
101 InstanceKlassFlags() : _flags(0), _status(0) {}
102
103 // Create getters and setters for the flag values.
104 #define IK_FLAGS_GET_SET(name, ignore) \
105 bool name() const { return (_flags & _misc_##name) != 0; } \
106 void set_##name(bool b) { \
107 assert_is_safe(name()); \
108 if (b) _flags |= _misc_##name; \
109 }
110 IK_FLAGS_DO(IK_FLAGS_GET_SET)
111 #undef IK_FLAGS_GET_SET
112
113 bool is_shared_unregistered_class() const {
114 return (_flags & shared_loader_type_bits()) == 0;
115 }
116
117 void set_shared_class_loader_type(s2 loader_type);
118
119 void assign_class_loader_type(const ClassLoaderData* cld);
120
121 u4 flags() const { return _flags; }
122
123 static u4 is_empty_inline_type_value() {
124 return _misc_is_empty_inline_type;
125 }
126
127 void assert_is_safe(bool set) NOT_DEBUG_RETURN;
128
129 // Create getters and setters for the status values.
130 #define IK_STATUS_GET_SET(name, ignore) \
131 bool name() const { return (_status & _misc_##name) != 0; } \
132 void set_##name(bool b) { \
133 if (b) { \
134 atomic_set_bits(_misc_##name); \
135 } else { \
136 atomic_clear_bits(_misc_##name); \
137 } \
138 }
139 IK_STATUS_DO(IK_STATUS_GET_SET)
140 #undef IK_STATUS_GET_SET
141
142 void atomic_set_bits(u1 bits) { Atomic::fetch_then_or(&_status, bits); }
143 void atomic_clear_bits(u1 bits) { Atomic::fetch_then_and(&_status, (u1)(~bits)); }
144 void print_on(outputStream* st) const;
145 };
146
147 #endif // SHARE_OOPS_INSTANCEKLASSFLAGS_HPP