1 /* 2 * Copyright (c) 1997, 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 #ifndef SHARE_VM_MEMORY_RESOURCEAREA_HPP 26 #define SHARE_VM_MEMORY_RESOURCEAREA_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/thread.inline.hpp" 30 31 // The resource area holds temporary data structures in the VM. 32 // The actual allocation areas are thread local. Typical usage: 33 // 34 // ... 35 // { 36 // ResourceMark rm; 37 // int foo[] = NEW_RESOURCE_ARRAY(int, 64); 38 // ... 39 // } 40 // ... 41 42 //------------------------------ResourceArea----------------------------------- 43 // A ResourceArea is an Arena that supports safe usage of ResourceMark. 44 class ResourceArea: public Arena { 45 friend class ResourceMark; 46 friend class DeoptResourceMark; 47 friend class VMStructs; 48 debug_only(int _nesting;) // current # of nested ResourceMarks 49 debug_only(static int _warned;) // to suppress multiple warnings 50 51 public: 52 ResourceArea() : Arena(mtThread) { 53 debug_only(_nesting = 0;) 54 } 55 56 ResourceArea(size_t init_size) : Arena(mtThread, init_size) { 57 debug_only(_nesting = 0;); 58 } 59 60 char* allocate_bytes(size_t size, AllocFailType alloc_failmode = AllocFailStrategy::EXIT_OOM) { 61 #ifdef ASSERT 62 if (_nesting < 1 && !_warned++) 63 fatal("memory leak: allocating without ResourceMark"); 64 if (UseMallocOnly) { 65 // use malloc, but save pointer in res. area for later freeing 66 char** save = (char**)internal_malloc_4(sizeof(char*)); 67 return (*save = (char*)os::malloc(size, mtThread, CURRENT_PC)); 68 } 69 #endif 70 return (char*)Amalloc(size, alloc_failmode); 71 } 72 73 debug_only(int nesting() const { return _nesting; }); 74 }; 75 76 77 //------------------------------ResourceMark----------------------------------- 78 // A resource mark releases all resources allocated after it was constructed 79 // when the destructor is called. Typically used as a local variable. 80 class ResourceMark: public StackObj { 81 protected: 82 ResourceArea *_area; // Resource area to stack allocate 83 Chunk *_chunk; // saved arena chunk 84 char *_hwm, *_max; 85 size_t _size_in_bytes; 86 #ifdef ASSERT 87 Thread* _thread; 88 ResourceMark* _previous_resource_mark; 89 #endif //ASSERT 90 91 void initialize(Thread *thread) { 92 _area = thread->resource_area(); 93 _chunk = _area->_chunk; 94 _hwm = _area->_hwm; 95 _max= _area->_max; 96 _size_in_bytes = _area->size_in_bytes(); 97 debug_only(_area->_nesting++;) 98 assert( _area->_nesting > 0, "must stack allocate RMs" ); 99 #ifdef ASSERT 100 _thread = thread; 101 _previous_resource_mark = thread->current_resource_mark(); 102 thread->set_current_resource_mark(this); 103 #endif // ASSERT 104 } 105 public: 106 107 #ifndef ASSERT 108 ResourceMark(Thread *thread) { 109 assert(thread == Thread::current(), "not the current thread"); 110 initialize(thread); 111 } 112 #else 113 ResourceMark(Thread *thread); 114 #endif // ASSERT 115 116 ResourceMark() { initialize(Thread::current()); } 117 118 ResourceMark( ResourceArea *r ) : 119 _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) { 120 _size_in_bytes = r->_size_in_bytes; 121 debug_only(_area->_nesting++;) 122 assert( _area->_nesting > 0, "must stack allocate RMs" ); 123 #ifdef ASSERT 124 Thread* thread = Thread::current_or_null(); 125 if (thread != NULL) { 126 _thread = thread; 127 _previous_resource_mark = thread->current_resource_mark(); 128 thread->set_current_resource_mark(this); 129 } else { 130 _thread = NULL; 131 _previous_resource_mark = NULL; 132 } 133 #endif // ASSERT 134 } 135 136 void reset_to_mark() { 137 if (UseMallocOnly) free_malloced_objects(); 138 139 if( _chunk->next() ) { // Delete later chunks 140 // reset arena size before delete chunks. Otherwise, the total 141 // arena size could exceed total chunk size 142 assert(_area->size_in_bytes() > size_in_bytes(), "Sanity check"); 143 _area->set_size_in_bytes(size_in_bytes()); 144 _chunk->next_chop(); 145 } else { 146 assert(_area->size_in_bytes() == size_in_bytes(), "Sanity check"); 147 } 148 _area->_chunk = _chunk; // Roll back arena to saved chunk 149 _area->_hwm = _hwm; 150 _area->_max = _max; 151 152 // clear out this chunk (to detect allocation bugs) 153 if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); 154 } 155 156 ~ResourceMark() { 157 assert( _area->_nesting > 0, "must stack allocate RMs" ); 158 debug_only(_area->_nesting--;) 159 reset_to_mark(); 160 #ifdef ASSERT 161 if (_thread != NULL) { 162 _thread->set_current_resource_mark(_previous_resource_mark); 163 } 164 #endif // ASSERT 165 } 166 167 168 private: 169 void free_malloced_objects() PRODUCT_RETURN; 170 size_t size_in_bytes() { return _size_in_bytes; } 171 }; 172 173 //------------------------------DeoptResourceMark----------------------------------- 174 // A deopt resource mark releases all resources allocated after it was constructed 175 // when the destructor is called. Typically used as a local variable. It differs 176 // from a typical resource more in that it is C-Heap allocated so that deoptimization 177 // can use data structures that are arena based but are not amenable to vanilla 178 // ResourceMarks because deoptimization can not use a stack allocated mark. During 179 // deoptimization we go thru the following steps: 180 // 181 // 0: start in assembly stub and call either uncommon_trap/fetch_unroll_info 182 // 1: create the vframeArray (contains pointers to Resource allocated structures) 183 // This allocates the DeoptResourceMark. 184 // 2: return to assembly stub and remove stub frame and deoptee frame and create 185 // the new skeletal frames. 186 // 3: push new stub frame and call unpack_frames 187 // 4: retrieve information from the vframeArray to populate the skeletal frames 188 // 5: release the DeoptResourceMark 189 // 6: return to stub and eventually to interpreter 190 // 191 // With old style eager deoptimization the vframeArray was created by the vmThread there 192 // was no way for the vframeArray to contain resource allocated objects and so 193 // a complex set of data structures to simulate an array of vframes in CHeap memory 194 // was used. With new style lazy deoptimization the vframeArray is created in the 195 // the thread that will use it and we can use a much simpler scheme for the vframeArray 196 // leveraging existing data structures if we simply create a way to manage this one 197 // special need for a ResourceMark. If ResourceMark simply inherited from CHeapObj 198 // then existing ResourceMarks would work fine since no one use new to allocate them 199 // and they would be stack allocated. This leaves open the possibility of accidental 200 // misuse so we simple duplicate the ResourceMark functionality here. 201 202 class DeoptResourceMark: public CHeapObj<mtInternal> { 203 protected: 204 ResourceArea *_area; // Resource area to stack allocate 205 Chunk *_chunk; // saved arena chunk 206 char *_hwm, *_max; 207 size_t _size_in_bytes; 208 209 void initialize(Thread *thread) { 210 _area = thread->resource_area(); 211 _chunk = _area->_chunk; 212 _hwm = _area->_hwm; 213 _max= _area->_max; 214 _size_in_bytes = _area->size_in_bytes(); 215 debug_only(_area->_nesting++;) 216 assert( _area->_nesting > 0, "must stack allocate RMs" ); 217 } 218 219 public: 220 221 #ifndef ASSERT 222 DeoptResourceMark(Thread *thread) { 223 assert(thread == Thread::current(), "not the current thread"); 224 initialize(thread); 225 } 226 #else 227 DeoptResourceMark(Thread *thread); 228 #endif // ASSERT 229 230 DeoptResourceMark() { initialize(Thread::current()); } 231 232 DeoptResourceMark( ResourceArea *r ) : 233 _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) { 234 _size_in_bytes = _area->size_in_bytes(); 235 debug_only(_area->_nesting++;) 236 assert( _area->_nesting > 0, "must stack allocate RMs" ); 237 } 238 239 void reset_to_mark() { 240 if (UseMallocOnly) free_malloced_objects(); 241 242 if( _chunk->next() ) { // Delete later chunks 243 // reset arena size before delete chunks. Otherwise, the total 244 // arena size could exceed total chunk size 245 assert(_area->size_in_bytes() > size_in_bytes(), "Sanity check"); 246 _area->set_size_in_bytes(size_in_bytes()); 247 _chunk->next_chop(); 248 } else { 249 assert(_area->size_in_bytes() == size_in_bytes(), "Sanity check"); 250 } 251 _area->_chunk = _chunk; // Roll back arena to saved chunk 252 _area->_hwm = _hwm; 253 _area->_max = _max; 254 255 // clear out this chunk (to detect allocation bugs) 256 if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); 257 } 258 259 ~DeoptResourceMark() { 260 assert( _area->_nesting > 0, "must stack allocate RMs" ); 261 debug_only(_area->_nesting--;) 262 reset_to_mark(); 263 } 264 265 266 private: 267 void free_malloced_objects() PRODUCT_RETURN; 268 size_t size_in_bytes() { return _size_in_bytes; }; 269 }; 270 271 #endif // SHARE_VM_MEMORY_RESOURCEAREA_HPP