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 #include "precompiled.hpp" 26 #include "code/codeBlob.hpp" 27 #include "code/stubs.hpp" 28 #include "memory/allocation.inline.hpp" 29 #include "oops/oop.inline.hpp" 30 #include "runtime/mutexLocker.hpp" 31 32 33 // Implementation of StubQueue 34 // 35 // Standard wrap-around queue implementation; the queue dimensions 36 // are specified by the _queue_begin & _queue_end indices. The queue 37 // can be in two states (transparent to the outside): 38 // 39 // a) contiguous state: all queue entries in one block (or empty) 40 // 41 // Queue: |...|XXXXXXX|...............| 42 // ^0 ^begin ^end ^size = limit 43 // |_______| 44 // one block 45 // 46 // b) non-contiguous state: queue entries in two blocks 47 // 48 // Queue: |XXX|.......|XXXXXXX|.......| 49 // ^0 ^end ^begin ^limit ^size 50 // |___| |_______| 51 // 1st block 2nd block 52 // 53 // In the non-contiguous state, the wrap-around point is 54 // indicated via the _buffer_limit index since the last 55 // queue entry may not fill up the queue completely in 56 // which case we need to know where the 2nd block's end 57 // is to do the proper wrap-around. When removing the 58 // last entry of the 2nd block, _buffer_limit is reset 59 // to _buffer_size. 60 // 61 // CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE 62 // ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS! 63 64 65 StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size, 66 Mutex* lock, const char* name) : _mutex(lock) { 67 intptr_t size = round_to(buffer_size, 2*BytesPerWord); 68 BufferBlob* blob = BufferBlob::create(name, size); 69 if( blob == NULL) { 70 vm_exit_out_of_memory(size, OOM_MALLOC_ERROR, err_msg("CodeCache: no room for %s", name)); 71 } 72 _stub_interface = stub_interface; 73 _buffer_size = blob->content_size(); 74 _buffer_limit = blob->content_size(); 75 _stub_buffer = blob->content_begin(); 76 _queue_begin = 0; 77 _queue_end = 0; 78 _number_of_stubs = 0; 79 register_queue(this); 80 } 81 82 83 StubQueue::~StubQueue() { 84 // Note: Currently StubQueues are never destroyed so nothing needs to be done here. 85 // If we want to implement the destructor, we need to release the BufferBlob 86 // allocated in the constructor (i.e., we need to keep it around or look it 87 // up via CodeCache::find_blob(...). 88 Unimplemented(); 89 } 90 91 92 Stub* StubQueue::stub_containing(address pc) const { 93 if (contains(pc)) { 94 for (Stub* s = first(); s != NULL; s = next(s)) { 95 if (stub_contains(s, pc)) return s; 96 } 97 } 98 return NULL; 99 } 100 101 102 Stub* StubQueue::request_committed(int code_size) { 103 Stub* s = request(code_size); 104 CodeStrings strings; 105 if (s != NULL) commit(code_size, strings); 106 return s; 107 } 108 109 110 Stub* StubQueue::request(int requested_code_size) { 111 assert(requested_code_size > 0, "requested_code_size must be > 0"); 112 if (_mutex != NULL) _mutex->lock(); 113 Stub* s = current_stub(); 114 int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment); 115 if (requested_size <= available_space()) { 116 if (is_contiguous()) { 117 // Queue: |...|XXXXXXX|.............| 118 // ^0 ^begin ^end ^size = limit 119 assert(_buffer_limit == _buffer_size, "buffer must be fully usable"); 120 if (_queue_end + requested_size <= _buffer_size) { 121 // code fits in at the end => nothing to do 122 CodeStrings strings; 123 stub_initialize(s, requested_size, strings); 124 return s; 125 } else { 126 // stub doesn't fit in at the queue end 127 // => reduce buffer limit & wrap around 128 assert(!is_empty(), "just checkin'"); 129 _buffer_limit = _queue_end; 130 _queue_end = 0; 131 } 132 } 133 } 134 if (requested_size <= available_space()) { 135 assert(!is_contiguous(), "just checkin'"); 136 assert(_buffer_limit <= _buffer_size, "queue invariant broken"); 137 // Queue: |XXX|.......|XXXXXXX|.......| 138 // ^0 ^end ^begin ^limit ^size 139 s = current_stub(); 140 CodeStrings strings; 141 stub_initialize(s, requested_size, strings); 142 return s; 143 } 144 // Not enough space left 145 if (_mutex != NULL) _mutex->unlock(); 146 return NULL; 147 } 148 149 150 void StubQueue::commit(int committed_code_size, CodeStrings& strings) { 151 assert(committed_code_size > 0, "committed_code_size must be > 0"); 152 int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment); 153 Stub* s = current_stub(); 154 assert(committed_size <= stub_size(s), "committed size must not exceed requested size"); 155 stub_initialize(s, committed_size, strings); 156 _queue_end += committed_size; 157 _number_of_stubs++; 158 if (_mutex != NULL) _mutex->unlock(); 159 debug_only(stub_verify(s);) 160 } 161 162 163 void StubQueue::remove_first() { 164 if (number_of_stubs() == 0) return; 165 Stub* s = first(); 166 debug_only(stub_verify(s);) 167 stub_finalize(s); 168 _queue_begin += stub_size(s); 169 assert(_queue_begin <= _buffer_limit, "sanity check"); 170 if (_queue_begin == _queue_end) { 171 // buffer empty 172 // => reset queue indices 173 _queue_begin = 0; 174 _queue_end = 0; 175 _buffer_limit = _buffer_size; 176 } else if (_queue_begin == _buffer_limit) { 177 // buffer limit reached 178 // => reset buffer limit & wrap around 179 _buffer_limit = _buffer_size; 180 _queue_begin = 0; 181 } 182 _number_of_stubs--; 183 } 184 185 186 void StubQueue::remove_first(int n) { 187 int i = MIN2(n, number_of_stubs()); 188 while (i-- > 0) remove_first(); 189 } 190 191 192 void StubQueue::remove_all(){ 193 debug_only(verify();) 194 remove_first(number_of_stubs()); 195 assert(number_of_stubs() == 0, "sanity check"); 196 } 197 198 199 enum { StubQueueLimit = 10 }; // there are only a few in the world 200 static StubQueue* registered_stub_queues[StubQueueLimit]; 201 202 void StubQueue::register_queue(StubQueue* sq) { 203 for (int i = 0; i < StubQueueLimit; i++) { 204 if (registered_stub_queues[i] == NULL) { 205 registered_stub_queues[i] = sq; 206 return; 207 } 208 } 209 ShouldNotReachHere(); 210 } 211 212 213 void StubQueue::queues_do(void f(StubQueue* sq)) { 214 for (int i = 0; i < StubQueueLimit; i++) { 215 if (registered_stub_queues[i] != NULL) { 216 f(registered_stub_queues[i]); 217 } 218 } 219 } 220 221 222 void StubQueue::stubs_do(void f(Stub* s)) { 223 debug_only(verify();) 224 MutexLockerEx lock(_mutex); 225 for (Stub* s = first(); s != NULL; s = next(s)) f(s); 226 } 227 228 229 void StubQueue::verify() { 230 // verify only if initialized 231 if (_stub_buffer == NULL) return; 232 MutexLockerEx lock(_mutex); 233 // verify index boundaries 234 guarantee(0 <= _buffer_size, "buffer size must be positive"); 235 guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds"); 236 guarantee(0 <= _queue_begin && _queue_begin < _buffer_limit, "_queue_begin out of bounds"); 237 guarantee(0 <= _queue_end && _queue_end <= _buffer_limit, "_queue_end out of bounds"); 238 // verify alignment 239 guarantee(_buffer_size % CodeEntryAlignment == 0, "_buffer_size not aligned"); 240 guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned"); 241 guarantee(_queue_begin % CodeEntryAlignment == 0, "_queue_begin not aligned"); 242 guarantee(_queue_end % CodeEntryAlignment == 0, "_queue_end not aligned"); 243 // verify buffer limit/size relationship 244 if (is_contiguous()) { 245 guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size"); 246 } 247 // verify contents 248 int n = 0; 249 for (Stub* s = first(); s != NULL; s = next(s)) { 250 stub_verify(s); 251 n++; 252 } 253 guarantee(n == number_of_stubs(), "number of stubs inconsistent"); 254 guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same"); 255 } 256 257 258 void StubQueue::print() { 259 MutexLockerEx lock(_mutex); 260 for (Stub* s = first(); s != NULL; s = next(s)) { 261 stub_print(s); 262 } 263 } 264 265 // Fixup for pregenerated code 266 void StubQueue::fix_buffer(address buffer, address queue_end, address buffer_end, int number_of_stubs) { 267 const int extra_bytes = CodeEntryAlignment; 268 _stub_buffer = buffer; 269 _queue_begin = 0; 270 _queue_end = queue_end - buffer; 271 _number_of_stubs = number_of_stubs; 272 int size = buffer_end - buffer; 273 // Note: _buffer_limit must differ from _queue_end in the iteration loops 274 // => add extra space at the end (preserving alignment for asserts) if needed 275 if (buffer_end == queue_end) size += extra_bytes; 276 _buffer_limit = _buffer_size = size; 277 }