1 /*
2 * Copyright (c) 2022, 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.
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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23 */
24
25 #ifndef SHARE_CDS_CLASSPRELINKER_HPP
26 #define SHARE_CDS_CLASSPRELINKER_HPP
27
28 #include "interpreter/bytecodes.hpp"
29 #include "oops/oopsHierarchy.hpp"
30 #include "memory/allStatic.hpp"
31 #include "memory/allocation.hpp"
32 #include "runtime/handles.hpp"
33 #include "utilities/exceptions.hpp"
34 #include "utilities/macros.hpp"
35 #include "utilities/resourceHash.hpp"
36
37 class ConstantPool;
38 class constantPoolHandle;
39 class InstanceKlass;
40 class Klass;
41
42 // ClassPrelinker is used to perform ahead-of-time linking of ConstantPool entries
43 // for archived InstanceKlasses.
44 //
45 // At run time, Java classes are loaded dynamically and may be replaced with JVMTI.
46 // Therefore, we take care to prelink only the ConstantPool entries that are
47 // guatanteed to resolve to the same results at both dump time and run time.
48 //
49 // For example, a JVM_CONSTANT_Class reference to a supertype can be safely resolved
50 // at dump time, because at run time we will load a class from the CDS archive only
51 // if all of its supertypes are loaded from the CDS archive.
52 class ClassPrelinker : AllStatic {
53 using ClassesTable = ResourceHashtable<InstanceKlass*, bool, 15889, AnyObj::C_HEAP, mtClassShared> ;
54 static ClassesTable* _processed_classes;
55 static ClassesTable* _vm_classes;
56
57 static void add_one_vm_class(InstanceKlass* ik);
58
59 #ifdef ASSERT
60 static bool is_in_archivebuilder_buffer(address p);
61 #endif
62
63 template <typename T>
64 static bool is_in_archivebuilder_buffer(T p) {
65 return is_in_archivebuilder_buffer((address)(p));
66 }
67 static void resolve_string(constantPoolHandle cp, int cp_index, TRAPS) NOT_CDS_JAVA_HEAP_RETURN;
68 static bool is_class_resolution_deterministic(InstanceKlass* cp_holder, Klass* resolved_class);
69
70 static Klass* find_loaded_class(Thread* current, oop class_loader, Symbol* name);
71 static Klass* find_loaded_class(Thread* current, ConstantPool* cp, int class_cp_index);
72
73 // fmi = FieldRef/MethodRef/InterfaceMethodRef
74 static void maybe_resolve_fmi_ref(InstanceKlass* ik, Method* m, Bytecodes::Code bc, int raw_index,
75 GrowableArray<bool>* resolve_fmi_list, TRAPS);
76 public:
77 static void initialize();
78 static void dispose();
79
80 static void preresolve_class_cp_entries(JavaThread* current, InstanceKlass* ik, GrowableArray<bool>* preresolve_list);
81 static void preresolve_field_and_method_cp_entries(JavaThread* current, InstanceKlass* ik, GrowableArray<bool>* preresolve_list);
82
83 // Is this class resolved as part of vmClasses::resolve_all()? If so, these
84 // classes are guatanteed to be loaded at runtime (and cannot be replaced by JVMTI)
85 // when CDS is enabled. Therefore, we can safely keep a direct reference to these
86 // classes.
87 static bool is_vm_class(InstanceKlass* ik);
88
89 // Resolve all constant pool entries that are safe to be stored in the
90 // CDS archive.
91 static void dumptime_resolve_constants(InstanceKlass* ik, TRAPS);
92
93 static bool is_resolution_deterministic(ConstantPool* cp, int cp_index);
94 };
95
96 #endif // SHARE_CDS_CLASSPRELINKER_HPP