1 /*
2 * Copyright (c) 2018, 2023, 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 #ifndef SHARE_RUNTIME_JNIHANDLES_INLINE_HPP
26 #define SHARE_RUNTIME_JNIHANDLES_INLINE_HPP
27
28 #include "runtime/jniHandles.hpp"
29
30 #include "oops/access.inline.hpp"
31 #include "oops/oop.hpp"
32 #include "utilities/debug.hpp"
33 #include "utilities/globalDefinitions.hpp"
34
35 inline bool JNIHandles::is_tagged_with(jobject handle, TypeTag tag) {
36 return (reinterpret_cast<uintptr_t>(handle) & tag_mask) == tag;
37 }
38
39 inline bool JNIHandles::is_local_tagged(jobject handle) {
40 return is_tagged_with(handle, TypeTag::local);
41 }
42
43 inline bool JNIHandles::is_weak_global_tagged(jobject handle) {
44 return is_tagged_with(handle, TypeTag::weak_global);
45 }
46
47 inline bool JNIHandles::is_global_tagged(jobject handle) {
48 return is_tagged_with(handle, TypeTag::global);
49 }
50
51 inline oop* JNIHandles::local_ptr(jobject handle) {
52 assert(is_local_tagged(handle), "precondition");
53 STATIC_ASSERT(TypeTag::local == 0);
54 return reinterpret_cast<oop*>(handle);
55 }
56
57 inline oop* JNIHandles::global_ptr(jobject handle) {
58 assert(is_global_tagged(handle), "precondition");
59 char* ptr = reinterpret_cast<char*>(handle) - TypeTag::global;
60 return reinterpret_cast<oop*>(ptr);
61 }
62
63 inline oop* JNIHandles::weak_global_ptr(jweak handle) {
64 assert(is_weak_global_tagged(handle), "precondition");
65 char* ptr = reinterpret_cast<char*>(handle) - TypeTag::weak_global;
66 return reinterpret_cast<oop*>(ptr);
67 }
68
69 // external_guard is true if called from resolve_external_guard.
70 template <DecoratorSet decorators, bool external_guard>
71 inline oop JNIHandles::resolve_impl(jobject handle) {
72 assert(handle != nullptr, "precondition");
73 assert(!current_thread_in_native(), "must not be in native");
74 oop result;
75 if (is_weak_global_tagged(handle)) { // Unlikely
76 result = NativeAccess<ON_PHANTOM_OOP_REF|decorators>::oop_load(weak_global_ptr(handle));
77 } else if (is_global_tagged(handle)) {
78 result = NativeAccess<decorators>::oop_load(global_ptr(handle));
79 // Construction of jobjects canonicalize a null value into a null
80 // jobject, so for non-jweak the pointee should never be null.
81 assert(external_guard || result != nullptr, "Invalid JNI handle");
82 } else {
83 result = *local_ptr(handle);
84 // Construction of jobjects canonicalize a null value into a null
85 // jobject, so for non-jweak the pointee should never be null.
86 assert(external_guard || result != nullptr, "Invalid JNI handle");
87 }
88 return result;
89 }
90
91 inline oop JNIHandles::resolve(jobject handle) {
92 oop result = nullptr;
93 if (handle != nullptr) {
94 result = resolve_impl<DECORATORS_NONE, false /* external_guard */>(handle);
95 }
96 return result;
97 }
98
99 inline oop JNIHandles::resolve_no_keepalive(jobject handle) {
100 oop result = nullptr;
101 if (handle != nullptr) {
102 result = resolve_impl<AS_NO_KEEPALIVE, false /* external_guard */>(handle);
103 }
104 return result;
105 }
106
107 inline oop JNIHandles::resolve_non_null(jobject handle) {
108 assert(handle != nullptr, "JNI handle should not be null");
109 oop result = resolve_impl<DECORATORS_NONE, false /* external_guard */>(handle);
110 assert(result != nullptr, "null read from jni handle");
111 return result;
112 }
113
114 inline void JNIHandles::destroy_local(jobject handle) {
115 if (handle != nullptr) {
116 *local_ptr(handle) = nullptr;
117 }
118 }
119
120 #endif // SHARE_RUNTIME_JNIHANDLES_INLINE_HPP