1 /* 2 * Copyright (c) 2013, 2015, 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 #include "precompiled.hpp" 26 #include "classfile/metadataOnStackMark.hpp" 27 #include "code/codeCache.hpp" 28 #include "compiler/compileBroker.hpp" 29 #include "oops/metadata.hpp" 30 #include "prims/jvmtiImpl.hpp" 31 #include "runtime/synchronizer.hpp" 32 #include "runtime/thread.hpp" 33 #include "services/threadService.hpp" 34 #include "utilities/chunkedList.hpp" 35 #if INCLUDE_JVMCI 36 #include "jvmci/jvmciRuntime.hpp" 37 #endif 38 39 MetadataOnStackBuffer* MetadataOnStackMark::_used_buffers = NULL; 40 MetadataOnStackBuffer* MetadataOnStackMark::_free_buffers = NULL; 41 42 MetadataOnStackBuffer* MetadataOnStackMark::_current_buffer = NULL; 43 NOT_PRODUCT(bool MetadataOnStackMark::_is_active = false;) 44 45 // Walk metadata on the stack and mark it so that redefinition doesn't delete 46 // it. Class unloading only deletes in-error class files, methods created by 47 // the relocator and dummy constant pools. None of these appear anywhere except 48 // in metadata Handles. 49 MetadataOnStackMark::MetadataOnStackMark(bool redefinition_walk) { 50 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 51 assert(_used_buffers == NULL, "sanity check"); 52 assert(!_is_active, "MetadataOnStackMarks do not nest"); 53 NOT_PRODUCT(_is_active = true;) 54 55 Threads::metadata_handles_do(Metadata::mark_on_stack); 56 57 if (redefinition_walk) { 58 Threads::metadata_do(Metadata::mark_on_stack); 59 CodeCache::alive_nmethods_do(nmethod::mark_on_stack); 60 CompileBroker::mark_on_stack(); 61 JvmtiCurrentBreakpoints::metadata_do(Metadata::mark_on_stack); 62 ThreadService::metadata_do(Metadata::mark_on_stack); 63 #if INCLUDE_JVMCI 64 JVMCIRuntime::metadata_do(Metadata::mark_on_stack); 65 #endif 66 } 67 } 68 69 MetadataOnStackMark::~MetadataOnStackMark() { 70 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 71 // Unmark everything that was marked. Can't do the same walk because 72 // redefine classes messes up the code cache so the set of methods 73 // might not be the same. 74 retire_current_buffer(); 75 76 MetadataOnStackBuffer* buffer = _used_buffers; 77 while (buffer != NULL) { 78 // Clear on stack state for all metadata. 79 size_t size = buffer->size(); 80 for (size_t i = 0; i < size; i++) { 81 Metadata* md = buffer->at(i); 82 md->set_on_stack(false); 83 } 84 85 MetadataOnStackBuffer* next = buffer->next_used(); 86 87 // Move the buffer to the free list. 88 buffer->clear(); 89 buffer->set_next_used(NULL); 90 buffer->set_next_free(_free_buffers); 91 _free_buffers = buffer; 92 93 // Step to next used buffer. 94 buffer = next; 95 } 96 97 _used_buffers = NULL; 98 99 NOT_PRODUCT(_is_active = false;) 100 } 101 102 void MetadataOnStackMark::retire_buffer(MetadataOnStackBuffer* buffer) { 103 if (buffer == NULL) { 104 return; 105 } 106 buffer->set_next_used(_used_buffers); 107 _used_buffers = buffer; 108 } 109 110 // Current buffer is full or we're ready to walk them, add it to the used list. 111 void MetadataOnStackMark::retire_current_buffer() { 112 retire_buffer(_current_buffer); 113 _current_buffer = NULL; 114 } 115 116 // Get buffer off free list. 117 MetadataOnStackBuffer* MetadataOnStackMark::allocate_buffer() { 118 MetadataOnStackBuffer* allocated = _free_buffers; 119 120 if (allocated != NULL) { 121 _free_buffers = allocated->next_free(); 122 } 123 124 if (allocated == NULL) { 125 allocated = new MetadataOnStackBuffer(); 126 } 127 128 assert(!allocated->is_full(), err_msg("Should not be full: " PTR_FORMAT, p2i(allocated))); 129 130 return allocated; 131 } 132 133 // Record which objects are marked so we can unmark the same objects. 134 void MetadataOnStackMark::record(Metadata* m) { 135 assert(_is_active, "metadata on stack marking is active"); 136 137 MetadataOnStackBuffer* buffer = _current_buffer; 138 139 if (buffer != NULL && buffer->is_full()) { 140 retire_buffer(buffer); 141 buffer = NULL; 142 } 143 144 if (buffer == NULL) { 145 buffer = allocate_buffer(); 146 _current_buffer = buffer; 147 } 148 149 buffer->push(m); 150 }