1 /* 2 * Copyright (c) 2018, 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 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 40 inline oop* JNIHandles::jobject_ptr(jobject handle) { 41 assert(!is_jweak(handle), "precondition"); 42 return reinterpret_cast<oop*>(handle); 43 } 44 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<bool external_guard> 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 = resolve_jweak(handle); 59 } else { 60 result = RootAccess<IN_CONCURRENT_ROOT>::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 68 inline oop JNIHandles::resolve(jobject handle) { 69 oop result = NULL; 70 if (handle != NULL) { 71 result = resolve_impl<false /* external_guard */ >(handle); 72 } 73 return result; 74 } 75 76 inline oop JNIHandles::resolve_non_null(jobject handle) { 77 assert(handle != NULL, "JNI handle should not be null"); 78 oop result = resolve_impl<false /* external_guard */ >(handle); 79 assert(result != NULL, "NULL read from jni handle"); 80 return result; 81 } 82 83 inline void JNIHandles::destroy_local(jobject handle) { 84 if (handle != NULL) { 85 assert(!is_jweak(handle), "Invalid JNI local handle"); 86 RootAccess<>::oop_store(jobject_ptr(handle), (oop)NULL); 87 } 88 } 89 90 #endif // SHARE_RUNTIME_JNIHANDLES_INLINE_HPP 91