1 /* 2 * Copyright (c) 1997, 2011, 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 #ifdef TARGET_OS_FAMILY_linux 30 # include "thread_linux.inline.hpp" 31 #endif 32 #ifdef TARGET_OS_FAMILY_solaris 33 # include "thread_solaris.inline.hpp" 34 #endif 35 #ifdef TARGET_OS_FAMILY_windows 36 # include "thread_windows.inline.hpp" 37 #endif 38 39 // The resource area holds temporary data structures in the VM. 40 // The actual allocation areas are thread local. Typical usage: 41 // 42 // ... 43 // { 44 // ResourceMark rm; 45 // int foo[] = NEW_RESOURCE_ARRAY(int, 64); 46 // ... 47 // } 48 // ... 49 50 //------------------------------ResourceArea----------------------------------- 51 // A ResourceArea is an Arena that supports safe usage of ResourceMark. 52 class ResourceArea: public Arena { 53 friend class ResourceMark; 54 friend class DeoptResourceMark; 55 friend class VMStructs; 56 debug_only(int _nesting;) // current # of nested ResourceMarks 57 debug_only(static int _warned;) // to suppress multiple warnings 58 59 public: 60 ResourceArea() { 61 debug_only(_nesting = 0;) 62 } 63 64 ResourceArea(size_t init_size) : Arena(init_size) { 65 debug_only(_nesting = 0;); 66 } 67 68 char* allocate_bytes(size_t size) { 69 #ifdef ASSERT 70 if (_nesting < 1 && !_warned++) 71 fatal("memory leak: allocating without ResourceMark"); 72 if (UseMallocOnly) { 73 // use malloc, but save pointer in res. area for later freeing 74 char** save = (char**)internal_malloc_4(sizeof(char*)); 75 return (*save = (char*)os::malloc(size)); 76 } 77 #endif 78 return (char*)Amalloc(size); 79 } 80 81 debug_only(int nesting() const { return _nesting; }); 82 }; 83 84 85 //------------------------------ResourceMark----------------------------------- 86 // A resource mark releases all resources allocated after it was constructed 87 // when the destructor is called. Typically used as a local variable. 88 class ResourceMark: public StackObj { 89 protected: 90 ResourceArea *_area; // Resource area to stack allocate 91 Chunk *_chunk; // saved arena chunk 92 char *_hwm, *_max; 93 NOT_PRODUCT(size_t _size_in_bytes;) 94 95 void initialize(Thread *thread) { 96 _area = thread->resource_area(); 97 _chunk = _area->_chunk; 98 _hwm = _area->_hwm; 99 _max= _area->_max; 100 NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) 101 debug_only(_area->_nesting++;) 102 assert( _area->_nesting > 0, "must stack allocate RMs" ); 103 } 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 NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) 121 debug_only(_area->_nesting++;) 122 assert( _area->_nesting > 0, "must stack allocate RMs" ); 123 } 124 125 void reset_to_mark() { 126 if (UseMallocOnly) free_malloced_objects(); 127 128 if( _chunk->next() ) // Delete later chunks 129 _chunk->next_chop(); 130 _area->_chunk = _chunk; // Roll back arena to saved chunk 131 _area->_hwm = _hwm; 132 _area->_max = _max; 133 134 // clear out this chunk (to detect allocation bugs) 135 if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); 136 _area->set_size_in_bytes(size_in_bytes()); 137 } 138 139 ~ResourceMark() { 140 assert( _area->_nesting > 0, "must stack allocate RMs" ); 141 debug_only(_area->_nesting--;) 142 reset_to_mark(); 143 } 144 145 146 private: 147 void free_malloced_objects() PRODUCT_RETURN; 148 size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0; 149 }; 150 151 //------------------------------DeoptResourceMark----------------------------------- 152 // A deopt resource mark releases all resources allocated after it was constructed 153 // when the destructor is called. Typically used as a local variable. It differs 154 // from a typical resource more in that it is C-Heap allocated so that deoptimization 155 // can use data structures that are arena based but are not amenable to vanilla 156 // ResourceMarks because deoptimization can not use a stack allocated mark. During 157 // deoptimization we go thru the following steps: 158 // 159 // 0: start in assembly stub and call either uncommon_trap/fetch_unroll_info 160 // 1: create the vframeArray (contains pointers to Resource allocated structures) 161 // This allocates the DeoptResourceMark. 162 // 2: return to assembly stub and remove stub frame and deoptee frame and create 163 // the new skeletal frames. 164 // 3: push new stub frame and call unpack_frames 165 // 4: retrieve information from the vframeArray to populate the skeletal frames 166 // 5: release the DeoptResourceMark 167 // 6: return to stub and eventually to interpreter 168 // 169 // With old style eager deoptimization the vframeArray was created by the vmThread there 170 // was no way for the vframeArray to contain resource allocated objects and so 171 // a complex set of data structures to simulate an array of vframes in CHeap memory 172 // was used. With new style lazy deoptimization the vframeArray is created in the 173 // the thread that will use it and we can use a much simpler scheme for the vframeArray 174 // leveraging existing data structures if we simply create a way to manage this one 175 // special need for a ResourceMark. If ResourceMark simply inherited from CHeapObj 176 // then existing ResourceMarks would work fine since no one use new to allocate them 177 // and they would be stack allocated. This leaves open the possibilty of accidental 178 // misuse so we simple duplicate the ResourceMark functionality here. 179 180 class DeoptResourceMark: public CHeapObj { 181 protected: 182 ResourceArea *_area; // Resource area to stack allocate 183 Chunk *_chunk; // saved arena chunk 184 char *_hwm, *_max; 185 NOT_PRODUCT(size_t _size_in_bytes;) 186 187 void initialize(Thread *thread) { 188 _area = thread->resource_area(); 189 _chunk = _area->_chunk; 190 _hwm = _area->_hwm; 191 _max= _area->_max; 192 NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) 193 debug_only(_area->_nesting++;) 194 assert( _area->_nesting > 0, "must stack allocate RMs" ); 195 } 196 197 public: 198 199 #ifndef ASSERT 200 DeoptResourceMark(Thread *thread) { 201 assert(thread == Thread::current(), "not the current thread"); 202 initialize(thread); 203 } 204 #else 205 DeoptResourceMark(Thread *thread); 206 #endif // ASSERT 207 208 DeoptResourceMark() { initialize(Thread::current()); } 209 210 DeoptResourceMark( ResourceArea *r ) : 211 _area(r), _chunk(r->_chunk), _hwm(r->_hwm), _max(r->_max) { 212 NOT_PRODUCT(_size_in_bytes = _area->size_in_bytes();) 213 debug_only(_area->_nesting++;) 214 assert( _area->_nesting > 0, "must stack allocate RMs" ); 215 } 216 217 void reset_to_mark() { 218 if (UseMallocOnly) free_malloced_objects(); 219 220 if( _chunk->next() ) // Delete later chunks 221 _chunk->next_chop(); 222 _area->_chunk = _chunk; // Roll back arena to saved chunk 223 _area->_hwm = _hwm; 224 _area->_max = _max; 225 226 // clear out this chunk (to detect allocation bugs) 227 if (ZapResourceArea) memset(_hwm, badResourceValue, _max - _hwm); 228 _area->set_size_in_bytes(size_in_bytes()); 229 } 230 231 ~DeoptResourceMark() { 232 assert( _area->_nesting > 0, "must stack allocate RMs" ); 233 debug_only(_area->_nesting--;) 234 reset_to_mark(); 235 } 236 237 238 private: 239 void free_malloced_objects() PRODUCT_RETURN; 240 size_t size_in_bytes() NOT_PRODUCT({ return _size_in_bytes; }) PRODUCT_RETURN0; 241 }; 242 243 #endif // SHARE_VM_MEMORY_RESOURCEAREA_HPP