stubs.cpp revision 0:a61af66fc99e
1252867Sdelphij/* 2252867Sdelphij * Copyright 1997-2005 Sun Microsystems, Inc. All Rights Reserved. 3252867Sdelphij * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4252867Sdelphij * 5252867Sdelphij * This code is free software; you can redistribute it and/or modify it 6252867Sdelphij * under the terms of the GNU General Public License version 2 only, as 7252867Sdelphij * published by the Free Software Foundation. 8252867Sdelphij * 9252867Sdelphij * This code is distributed in the hope that it will be useful, but WITHOUT 10252867Sdelphij * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11252867Sdelphij * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12252867Sdelphij * version 2 for more details (a copy is included in the LICENSE file that 13252867Sdelphij * accompanied this code). 14252867Sdelphij * 15252867Sdelphij * You should have received a copy of the GNU General Public License version 16252867Sdelphij * 2 along with this work; if not, write to the Free Software Foundation, 17252867Sdelphij * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18252867Sdelphij * 19252867Sdelphij * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20252867Sdelphij * CA 95054 USA or visit www.sun.com if you need additional information or 21252867Sdelphij * have any questions. 22252867Sdelphij * 23252867Sdelphij */ 24252867Sdelphij 25252867Sdelphij#include "incls/_precompiled.incl" 26252867Sdelphij#include "incls/_stubs.cpp.incl" 27252867Sdelphij 28252867Sdelphij 29252867Sdelphij// Implementation of StubQueue 30252867Sdelphij// 31252867Sdelphij// Standard wrap-around queue implementation; the queue dimensions 32252867Sdelphij// are specified by the _queue_begin & _queue_end indices. The queue 33252867Sdelphij// can be in two states (transparent to the outside): 34252867Sdelphij// 35252867Sdelphij// a) contiguous state: all queue entries in one block (or empty) 36252867Sdelphij// 37252867Sdelphij// Queue: |...|XXXXXXX|...............| 38252867Sdelphij// ^0 ^begin ^end ^size = limit 39252867Sdelphij// |_______| 40252867Sdelphij// one block 41252867Sdelphij// 42252867Sdelphij// b) non-contiguous state: queue entries in two blocks 43252867Sdelphij// 44252867Sdelphij// Queue: |XXX|.......|XXXXXXX|.......| 45252867Sdelphij// ^0 ^end ^begin ^limit ^size 46252867Sdelphij// |___| |_______| 47252867Sdelphij// 1st block 2nd block 48252867Sdelphij// 49326005Sdelphij// In the non-contiguous state, the wrap-around point is 50252867Sdelphij// indicated via the _buffer_limit index since the last 51252867Sdelphij// queue entry may not fill up the queue completely in 52252867Sdelphij// which case we need to know where the 2nd block's end 53252867Sdelphij// is to do the proper wrap-around. When removing the 54// last entry of the 2nd block, _buffer_limit is reset 55// to _buffer_size. 56// 57// CAUTION: DO NOT MESS WITH THIS CODE IF YOU CANNOT PROVE 58// ITS CORRECTNESS! THIS CODE IS MORE SUBTLE THAN IT LOOKS! 59 60 61StubQueue::StubQueue(StubInterface* stub_interface, int buffer_size, 62 Mutex* lock, const char* name) : _mutex(lock) { 63 intptr_t size = round_to(buffer_size, 2*BytesPerWord); 64 BufferBlob* blob = BufferBlob::create(name, size); 65 if( blob == NULL ) vm_exit_out_of_memory1(size, "CodeCache: no room for %s", name); 66 _stub_interface = stub_interface; 67 _buffer_size = blob->instructions_size(); 68 _buffer_limit = blob->instructions_size(); 69 _stub_buffer = blob->instructions_begin(); 70 _queue_begin = 0; 71 _queue_end = 0; 72 _number_of_stubs = 0; 73 register_queue(this); 74} 75 76 77StubQueue::~StubQueue() { 78 // Note: Currently StubQueues are never destroyed so nothing needs to be done here. 79 // If we want to implement the destructor, we need to release the BufferBlob 80 // allocated in the constructor (i.e., we need to keep it around or look it 81 // up via CodeCache::find_blob(...). 82 Unimplemented(); 83} 84 85 86Stub* StubQueue::stub_containing(address pc) const { 87 if (contains(pc)) { 88 for (Stub* s = first(); s != NULL; s = next(s)) { 89 if (stub_contains(s, pc)) return s; 90 } 91 } 92 return NULL; 93} 94 95 96Stub* StubQueue::request_committed(int code_size) { 97 Stub* s = request(code_size); 98 if (s != NULL) commit(code_size); 99 return s; 100} 101 102 103Stub* StubQueue::request(int requested_code_size) { 104 assert(requested_code_size > 0, "requested_code_size must be > 0"); 105 if (_mutex != NULL) _mutex->lock(); 106 Stub* s = current_stub(); 107 int requested_size = round_to(stub_code_size_to_size(requested_code_size), CodeEntryAlignment); 108 if (requested_size <= available_space()) { 109 if (is_contiguous()) { 110 // Queue: |...|XXXXXXX|.............| 111 // ^0 ^begin ^end ^size = limit 112 assert(_buffer_limit == _buffer_size, "buffer must be fully usable"); 113 if (_queue_end + requested_size <= _buffer_size) { 114 // code fits in at the end => nothing to do 115 stub_initialize(s, requested_size); 116 return s; 117 } else { 118 // stub doesn't fit in at the queue end 119 // => reduce buffer limit & wrap around 120 assert(!is_empty(), "just checkin'"); 121 _buffer_limit = _queue_end; 122 _queue_end = 0; 123 } 124 } 125 } 126 if (requested_size <= available_space()) { 127 assert(!is_contiguous(), "just checkin'"); 128 assert(_buffer_limit <= _buffer_size, "queue invariant broken"); 129 // Queue: |XXX|.......|XXXXXXX|.......| 130 // ^0 ^end ^begin ^limit ^size 131 s = current_stub(); 132 stub_initialize(s, requested_size); 133 return s; 134 } 135 // Not enough space left 136 if (_mutex != NULL) _mutex->unlock(); 137 return NULL; 138} 139 140 141void StubQueue::commit(int committed_code_size) { 142 assert(committed_code_size > 0, "committed_code_size must be > 0"); 143 int committed_size = round_to(stub_code_size_to_size(committed_code_size), CodeEntryAlignment); 144 Stub* s = current_stub(); 145 assert(committed_size <= stub_size(s), "committed size must not exceed requested size"); 146 stub_initialize(s, committed_size); 147 _queue_end += committed_size; 148 _number_of_stubs++; 149 if (_mutex != NULL) _mutex->unlock(); 150 debug_only(stub_verify(s);) 151} 152 153 154void StubQueue::remove_first() { 155 if (number_of_stubs() == 0) return; 156 Stub* s = first(); 157 debug_only(stub_verify(s);) 158 stub_finalize(s); 159 _queue_begin += stub_size(s); 160 assert(_queue_begin <= _buffer_limit, "sanity check"); 161 if (_queue_begin == _queue_end) { 162 // buffer empty 163 // => reset queue indices 164 _queue_begin = 0; 165 _queue_end = 0; 166 _buffer_limit = _buffer_size; 167 } else if (_queue_begin == _buffer_limit) { 168 // buffer limit reached 169 // => reset buffer limit & wrap around 170 _buffer_limit = _buffer_size; 171 _queue_begin = 0; 172 } 173 _number_of_stubs--; 174} 175 176 177void StubQueue::remove_first(int n) { 178 int i = MIN2(n, number_of_stubs()); 179 while (i-- > 0) remove_first(); 180} 181 182 183void StubQueue::remove_all(){ 184 debug_only(verify();) 185 remove_first(number_of_stubs()); 186 assert(number_of_stubs() == 0, "sanity check"); 187} 188 189 190enum { StubQueueLimit = 10 }; // there are only a few in the world 191static StubQueue* registered_stub_queues[StubQueueLimit]; 192 193void StubQueue::register_queue(StubQueue* sq) { 194 for (int i = 0; i < StubQueueLimit; i++) { 195 if (registered_stub_queues[i] == NULL) { 196 registered_stub_queues[i] = sq; 197 return; 198 } 199 } 200 ShouldNotReachHere(); 201} 202 203 204void StubQueue::queues_do(void f(StubQueue* sq)) { 205 for (int i = 0; i < StubQueueLimit; i++) { 206 if (registered_stub_queues[i] != NULL) { 207 f(registered_stub_queues[i]); 208 } 209 } 210} 211 212 213void StubQueue::stubs_do(void f(Stub* s)) { 214 debug_only(verify();) 215 MutexLockerEx lock(_mutex); 216 for (Stub* s = first(); s != NULL; s = next(s)) f(s); 217} 218 219 220void StubQueue::verify() { 221 // verify only if initialized 222 if (_stub_buffer == NULL) return; 223 MutexLockerEx lock(_mutex); 224 // verify index boundaries 225 guarantee(0 <= _buffer_size, "buffer size must be positive"); 226 guarantee(0 <= _buffer_limit && _buffer_limit <= _buffer_size , "_buffer_limit out of bounds"); 227 guarantee(0 <= _queue_begin && _queue_begin < _buffer_limit, "_queue_begin out of bounds"); 228 guarantee(0 <= _queue_end && _queue_end <= _buffer_limit, "_queue_end out of bounds"); 229 // verify alignment 230 guarantee(_buffer_size % CodeEntryAlignment == 0, "_buffer_size not aligned"); 231 guarantee(_buffer_limit % CodeEntryAlignment == 0, "_buffer_limit not aligned"); 232 guarantee(_queue_begin % CodeEntryAlignment == 0, "_queue_begin not aligned"); 233 guarantee(_queue_end % CodeEntryAlignment == 0, "_queue_end not aligned"); 234 // verify buffer limit/size relationship 235 if (is_contiguous()) { 236 guarantee(_buffer_limit == _buffer_size, "_buffer_limit must equal _buffer_size"); 237 } 238 // verify contents 239 int n = 0; 240 for (Stub* s = first(); s != NULL; s = next(s)) { 241 stub_verify(s); 242 n++; 243 } 244 guarantee(n == number_of_stubs(), "number of stubs inconsistent"); 245 guarantee(_queue_begin != _queue_end || n == 0, "buffer indices must be the same"); 246} 247 248 249void StubQueue::print() { 250 MutexLockerEx lock(_mutex); 251 for (Stub* s = first(); s != NULL; s = next(s)) { 252 stub_print(s); 253 } 254} 255