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