1 /*
2 * Copyright (c) 2018, 2019, 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 "oops/access.inline.hpp"
29 #include "oops/oop.hpp"
30 #include "runtime/jniHandles.hpp"
31 #include "utilities/debug.hpp"
32 #include "utilities/globalDefinitions.hpp"
33
is_jweak(jobject handle)34 inline bool JNIHandles::is_jweak(jobject handle) {
35 STATIC_ASSERT(weak_tag_size == 1);
36 STATIC_ASSERT(weak_tag_value == 1);
37 return (reinterpret_cast<uintptr_t>(handle) & weak_tag_mask) != 0;
38 }
39
jobject_ptr(jobject handle)40 inline oop* JNIHandles::jobject_ptr(jobject handle) {
41 assert(!is_jweak(handle), "precondition");
42 return reinterpret_cast<oop*>(handle);
43 }
44
jweak_ptr(jobject handle)45 inline oop* JNIHandles::jweak_ptr(jobject handle) {
46 assert(is_jweak(handle), "precondition");
47 char* ptr = reinterpret_cast<char*>(handle) - weak_tag_value;
48 return reinterpret_cast<oop*>(ptr);
49 }
50
51 // external_guard is true if called from resolve_external_guard.
52 template <DecoratorSet decorators, bool external_guard>
resolve_impl(jobject handle)53 inline oop JNIHandles::resolve_impl(jobject handle) {
54 assert(handle != NULL, "precondition");
55 assert(!current_thread_in_native(), "must not be in native");
56 oop result;
57 if (is_jweak(handle)) { // Unlikely
58 result = NativeAccess<ON_PHANTOM_OOP_REF|decorators>::oop_load(jweak_ptr(handle));
59 } else {
60 result = NativeAccess<decorators>::oop_load(jobject_ptr(handle));
61 // Construction of jobjects canonicalize a null value into a null
62 // jobject, so for non-jweak the pointee should never be null.
63 assert(external_guard || result != NULL, "Invalid JNI handle");
64 }
65 return result;
66 }
67
resolve(jobject handle)68 inline oop JNIHandles::resolve(jobject handle) {
69 oop result = NULL;
70 if (handle != NULL) {
71 result = resolve_impl<DECORATORS_NONE, false /* external_guard */>(handle);
72 }
73 return result;
74 }
75
resolve_no_keepalive(jobject handle)76 inline oop JNIHandles::resolve_no_keepalive(jobject handle) {
77 oop result = NULL;
78 if (handle != NULL) {
79 result = resolve_impl<AS_NO_KEEPALIVE, false /* external_guard */>(handle);
80 }
81 return result;
82 }
83
is_same_object(jobject handle1,jobject handle2)84 inline bool JNIHandles::is_same_object(jobject handle1, jobject handle2) {
85 oop obj1 = resolve_no_keepalive(handle1);
86 oop obj2 = resolve_no_keepalive(handle2);
87 return obj1 == obj2;
88 }
89
resolve_non_null(jobject handle)90 inline oop JNIHandles::resolve_non_null(jobject handle) {
91 assert(handle != NULL, "JNI handle should not be null");
92 oop result = resolve_impl<DECORATORS_NONE, false /* external_guard */>(handle);
93 assert(result != NULL, "NULL read from jni handle");
94 return result;
95 }
96
destroy_local(jobject handle)97 inline void JNIHandles::destroy_local(jobject handle) {
98 if (handle != NULL) {
99 assert(!is_jweak(handle), "Invalid JNI local handle");
100 NativeAccess<>::oop_store(jobject_ptr(handle), (oop)NULL);
101 }
102 }
103
104 #endif // SHARE_RUNTIME_JNIHANDLES_INLINE_HPP
105