1 /* 2 * Copyright 1998-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, 20 * CA 95054 USA or visit www.sun.com if you need additional information or 21 * have any questions. 22 * 23 */ 24 25 # include "incls/_precompiled.incl" 26 # include "incls/_debugInfoRec.cpp.incl" 27 28 // Private definition. 29 // There is one DIR_Chunk for each scope and values array. 30 // A chunk can potentially be used more than once. 31 // We keep track of these chunks in order to detect 32 // repetition and enable sharing. 33 class DIR_Chunk { 34 friend class DebugInformationRecorder; 35 int _offset; // location in the stream of this scope 36 int _length; // number of bytes in the stream 37 int _hash; // hash of stream bytes (for quicker reuse) 38 39 void* operator new(size_t ignore, DebugInformationRecorder* dir) { 40 assert(ignore == sizeof(DIR_Chunk), ""); 41 if (dir->_next_chunk >= dir->_next_chunk_limit) { 42 const int CHUNK = 100; 43 dir->_next_chunk = NEW_RESOURCE_ARRAY(DIR_Chunk, CHUNK); 44 dir->_next_chunk_limit = dir->_next_chunk + CHUNK; 45 } 46 return dir->_next_chunk++; 47 } 48 49 DIR_Chunk(int offset, int length, DebugInformationRecorder* dir) { 50 _offset = offset; 51 _length = length; 52 unsigned int hash = 0; 53 address p = dir->stream()->buffer() + _offset; 54 for (int i = 0; i < length; i++) { 55 if (i == 6) break; 56 hash *= 127; 57 hash += p[i]; 58 } 59 _hash = hash; 60 } 61 62 DIR_Chunk* find_match(GrowableArray<DIR_Chunk*>* arr, 63 int start_index, 64 DebugInformationRecorder* dir) { 65 int end_index = arr->length(); 66 int hash = this->_hash, length = this->_length; 67 address buf = dir->stream()->buffer(); 68 for (int i = end_index; --i >= start_index; ) { 69 DIR_Chunk* that = arr->at(i); 70 if (hash == that->_hash && 71 length == that->_length && 72 0 == memcmp(buf + this->_offset, buf + that->_offset, length)) { 73 return that; 74 } 75 } 76 return NULL; 77 } 78 }; 79 80 static inline bool compute_recording_non_safepoints() { 81 if (JvmtiExport::should_post_compiled_method_load() 82 && FLAG_IS_DEFAULT(DebugNonSafepoints)) { 83 // The default value of this flag is taken to be true, 84 // if JVMTI is looking at nmethod codes. 85 // We anticipate that JVMTI may wish to participate in profiling. 86 return true; 87 } 88 89 // If the flag is set manually, use it, whether true or false. 90 // Otherwise, if JVMTI is not in the picture, use the default setting. 91 // (This is true in debug, just for the exercise, false in product mode.) 92 return DebugNonSafepoints; 93 } 94 95 DebugInformationRecorder::DebugInformationRecorder(OopRecorder* oop_recorder) 96 : _recording_non_safepoints(compute_recording_non_safepoints()) 97 { 98 _pcs_size = 100; 99 _pcs = NEW_RESOURCE_ARRAY(PcDesc, _pcs_size); 100 _pcs_length = 0; 101 102 _prev_safepoint_pc = PcDesc::lower_offset_limit; 103 104 _stream = new DebugInfoWriteStream(this, 10 * K); 105 // make sure that there is no stream_decode_offset that is zero 106 _stream->write_byte((jbyte)0xFF); 107 108 // make sure that we can distinguish the value "serialized_null" from offsets 109 assert(_stream->position() > serialized_null, "sanity"); 110 111 _oop_recorder = oop_recorder; 112 113 _all_chunks = new GrowableArray<DIR_Chunk*>(300); 114 _shared_chunks = new GrowableArray<DIR_Chunk*>(30); 115 _next_chunk = _next_chunk_limit = NULL; 116 117 add_new_pc_offset(PcDesc::lower_offset_limit); // sentinel record 118 119 debug_only(_recording_state = rs_null); 120 } 121 122 123 void DebugInformationRecorder::add_oopmap(int pc_offset, OopMap* map) { 124 // !!!!! Preserve old style handling of oopmaps for now 125 _oopmaps->add_gc_map(pc_offset, map); 126 } 127 128 void DebugInformationRecorder::add_safepoint(int pc_offset, OopMap* map) { 129 assert(!_oop_recorder->is_complete(), "not frozen yet"); 130 // Store the new safepoint 131 132 // Add the oop map 133 add_oopmap(pc_offset, map); 134 135 add_new_pc_offset(pc_offset); 136 137 assert(_recording_state == rs_null, "nesting of recording calls"); 138 debug_only(_recording_state = rs_safepoint); 139 } 140 141 void DebugInformationRecorder::add_non_safepoint(int pc_offset) { 142 assert(!_oop_recorder->is_complete(), "not frozen yet"); 143 assert(_recording_non_safepoints, "must be recording non-safepoints"); 144 145 add_new_pc_offset(pc_offset); 146 147 assert(_recording_state == rs_null, "nesting of recording calls"); 148 debug_only(_recording_state = rs_non_safepoint); 149 } 150 151 void DebugInformationRecorder::add_new_pc_offset(int pc_offset) { 152 assert(_pcs_length == 0 || last_pc()->pc_offset() < pc_offset, 153 "must specify a new, larger pc offset"); 154 155 // add the pcdesc 156 if (_pcs_length == _pcs_size) { 157 // Expand 158 int new_pcs_size = _pcs_size * 2; 159 PcDesc* new_pcs = NEW_RESOURCE_ARRAY(PcDesc, new_pcs_size); 160 for (int index = 0; index < _pcs_length; index++) { 161 new_pcs[index] = _pcs[index]; 162 } 163 _pcs_size = new_pcs_size; 164 _pcs = new_pcs; 165 } 166 assert(_pcs_size > _pcs_length, "There must be room for after expanding"); 167 168 _pcs[_pcs_length++] = PcDesc(pc_offset, DebugInformationRecorder::serialized_null, 169 DebugInformationRecorder::serialized_null); 170 } 171 172 173 int DebugInformationRecorder::serialize_monitor_values(GrowableArray<MonitorValue*>* monitors) { 174 if (monitors == NULL || monitors->is_empty()) return DebugInformationRecorder::serialized_null; 175 assert(_recording_state == rs_safepoint, "must be recording a safepoint"); 176 int result = stream()->position(); 177 stream()->write_int(monitors->length()); 178 for (int index = 0; index < monitors->length(); index++) { 179 monitors->at(index)->write_on(stream()); 180 } 181 assert(result != serialized_null, "sanity"); 182 183 // (See comment below on DebugInformationRecorder::describe_scope.) 184 int shared_result = find_sharable_decode_offset(result); 185 if (shared_result != serialized_null) { 186 stream()->set_position(result); 187 result = shared_result; 188 } 189 190 return result; 191 } 192 193 194 int DebugInformationRecorder::serialize_scope_values(GrowableArray<ScopeValue*>* values) { 195 if (values == NULL || values->is_empty()) return DebugInformationRecorder::serialized_null; 196 assert(_recording_state == rs_safepoint, "must be recording a safepoint"); 197 int result = stream()->position(); 198 assert(result != serialized_null, "sanity"); 199 stream()->write_int(values->length()); 200 for (int index = 0; index < values->length(); index++) { 201 values->at(index)->write_on(stream()); 202 } 203 204 // (See comment below on DebugInformationRecorder::describe_scope.) 205 int shared_result = find_sharable_decode_offset(result); 206 if (shared_result != serialized_null) { 207 stream()->set_position(result); 208 result = shared_result; 209 } 210 211 return result; 212 } 213 214 215 #ifndef PRODUCT 216 // These variables are put into one block to reduce relocations 217 // and make it simpler to print from the debugger. 218 static 219 struct dir_stats_struct { 220 int chunks_queried; 221 int chunks_shared; 222 int chunks_reshared; 223 int chunks_elided; 224 225 void print() { 226 tty->print_cr("Debug Data Chunks: %d, shared %d+%d, non-SP's elided %d", 227 chunks_queried, 228 chunks_shared, chunks_reshared, 229 chunks_elided); 230 } 231 } dir_stats; 232 #endif //PRODUCT 233 234 235 int DebugInformationRecorder::find_sharable_decode_offset(int stream_offset) { 236 // Only pull this trick if non-safepoint recording 237 // is enabled, for now. 238 if (!recording_non_safepoints()) 239 return serialized_null; 240 241 NOT_PRODUCT(++dir_stats.chunks_queried); 242 int stream_length = stream()->position() - stream_offset; 243 assert(stream_offset != serialized_null, "should not be null"); 244 assert(stream_length != 0, "should not be empty"); 245 246 DIR_Chunk* ns = new(this) DIR_Chunk(stream_offset, stream_length, this); 247 248 // Look in previously shared scopes first: 249 DIR_Chunk* ms = ns->find_match(_shared_chunks, 0, this); 250 if (ms != NULL) { 251 NOT_PRODUCT(++dir_stats.chunks_reshared); 252 assert(ns+1 == _next_chunk, ""); 253 _next_chunk = ns; 254 return ms->_offset; 255 } 256 257 // Look in recently encountered scopes next: 258 const int MAX_RECENT = 50; 259 int start_index = _all_chunks->length() - MAX_RECENT; 260 if (start_index < 0) start_index = 0; 261 ms = ns->find_match(_all_chunks, start_index, this); 262 if (ms != NULL) { 263 NOT_PRODUCT(++dir_stats.chunks_shared); 264 // Searching in _all_chunks is limited to a window, 265 // but searching in _shared_chunks is unlimited. 266 _shared_chunks->append(ms); 267 assert(ns+1 == _next_chunk, ""); 268 _next_chunk = ns; 269 return ms->_offset; 270 } 271 272 // No match. Add this guy to the list, in hopes of future shares. 273 _all_chunks->append(ns); 274 return serialized_null; 275 } 276 277 278 // must call add_safepoint before: it sets PcDesc and this routine uses 279 // the last PcDesc set 280 void DebugInformationRecorder::describe_scope(int pc_offset, 281 ciMethod* method, 282 int bci, 283 DebugToken* locals, 284 DebugToken* expressions, 285 DebugToken* monitors) { 286 assert(_recording_state != rs_null, "nesting of recording calls"); 287 PcDesc* last_pd = last_pc(); 288 assert(last_pd->pc_offset() == pc_offset, "must be last pc"); 289 int sender_stream_offset = last_pd->scope_decode_offset(); 290 // update the stream offset of current pc desc 291 int stream_offset = stream()->position(); 292 last_pd->set_scope_decode_offset(stream_offset); 293 294 // serialize sender stream offest 295 stream()->write_int(sender_stream_offset); 296 297 // serialize scope 298 jobject method_enc = (method == NULL)? NULL: method->encoding(); 299 stream()->write_int(oop_recorder()->find_index(method_enc)); 300 stream()->write_bci(bci); 301 assert(method == NULL || 302 (method->is_native() && bci == 0) || 303 (!method->is_native() && 0 <= bci && bci < method->code_size()) || 304 bci == -1, "illegal bci"); 305 306 // serialize the locals/expressions/monitors 307 stream()->write_int((intptr_t) locals); 308 stream()->write_int((intptr_t) expressions); 309 stream()->write_int((intptr_t) monitors); 310 311 // Here's a tricky bit. We just wrote some bytes. 312 // Wouldn't it be nice to find that we had already 313 // written those same bytes somewhere else? 314 // If we get lucky this way, reset the stream 315 // and reuse the old bytes. By the way, this 316 // trick not only shares parent scopes, but also 317 // compresses equivalent non-safepoint PcDescs. 318 int shared_stream_offset = find_sharable_decode_offset(stream_offset); 319 if (shared_stream_offset != serialized_null) { 320 stream()->set_position(stream_offset); 321 last_pd->set_scope_decode_offset(shared_stream_offset); 322 } 323 } 324 325 void DebugInformationRecorder::dump_object_pool(GrowableArray<ScopeValue*>* objects) { 326 guarantee( _pcs_length > 0, "safepoint must exist before describing scopes"); 327 PcDesc* last_pd = &_pcs[_pcs_length-1]; 328 if (objects != NULL) { 329 for (int i = objects->length() - 1; i >= 0; i--) { 330 ((ObjectValue*) objects->at(i))->set_visited(false); 331 } 332 } 333 int offset = serialize_scope_values(objects); 334 last_pd->set_obj_decode_offset(offset); 335 } 336 337 void DebugInformationRecorder::end_scopes(int pc_offset, bool is_safepoint) { 338 assert(_recording_state == (is_safepoint? rs_safepoint: rs_non_safepoint), 339 "nesting of recording calls"); 340 debug_only(_recording_state = rs_null); 341 342 // Try to compress away an equivalent non-safepoint predecessor. 343 // (This only works because we have previously recognized redundant 344 // scope trees and made them use a common scope_decode_offset.) 345 if (_pcs_length >= 2 && recording_non_safepoints()) { 346 PcDesc* last = last_pc(); 347 PcDesc* prev = prev_pc(); 348 // If prev is (a) not a safepoint and (b) has the same 349 // stream pointer, then it can be coalesced into the last. 350 // This is valid because non-safepoints are only sought 351 // with pc_desc_near, which (when it misses prev) will 352 // search forward until it finds last. 353 // In addition, it does not matter if the last PcDesc 354 // is for a safepoint or not. 355 if (_prev_safepoint_pc < prev->pc_offset() && 356 prev->scope_decode_offset() == last->scope_decode_offset()) { 357 assert(prev == last-1, "sane"); 358 prev->set_pc_offset(pc_offset); 359 _pcs_length -= 1; 360 NOT_PRODUCT(++dir_stats.chunks_elided); 361 } 362 } 363 364 // We have just recorded this safepoint. 365 // Remember it in case the previous paragraph needs to know. 366 if (is_safepoint) { 367 _prev_safepoint_pc = pc_offset; 368 } 369 } 370 371 DebugToken* DebugInformationRecorder::create_scope_values(GrowableArray<ScopeValue*>* values) { 372 assert(!_oop_recorder->is_complete(), "not frozen yet"); 373 return (DebugToken*) (intptr_t) serialize_scope_values(values); 374 } 375 376 377 DebugToken* DebugInformationRecorder::create_monitor_values(GrowableArray<MonitorValue*>* monitors) { 378 assert(!_oop_recorder->is_complete(), "not frozen yet"); 379 return (DebugToken*) (intptr_t) serialize_monitor_values(monitors); 380 } 381 382 383 int DebugInformationRecorder::data_size() { 384 debug_only(_oop_recorder->oop_size()); // mark it "frozen" for asserts 385 return _stream->position(); 386 } 387 388 389 int DebugInformationRecorder::pcs_size() { 390 debug_only(_oop_recorder->oop_size()); // mark it "frozen" for asserts 391 if (last_pc()->pc_offset() != PcDesc::upper_offset_limit) 392 add_new_pc_offset(PcDesc::upper_offset_limit); 393 return _pcs_length * sizeof(PcDesc); 394 } 395 396 397 void DebugInformationRecorder::copy_to(nmethod* nm) { 398 nm->copy_scopes_data(stream()->buffer(), stream()->position()); 399 nm->copy_scopes_pcs(_pcs, _pcs_length); 400 } 401 402 403 void DebugInformationRecorder::verify(const nmethod* code) { 404 Unimplemented(); 405 } 406 407 #ifndef PRODUCT 408 void DebugInformationRecorder::print_statistics() { 409 dir_stats.print(); 410 } 411 #endif //PRODUCT