1 /* 2 * Copyright (c) 1998, 2013, 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/debugInfoRec.hpp" 27 #include "code/scopeDesc.hpp" 28 #include "prims/jvmtiExport.hpp" 29 30 // Private definition. 31 // There is one DIR_Chunk for each scope and values array. 32 // A chunk can potentially be used more than once. 33 // We keep track of these chunks in order to detect 34 // repetition and enable sharing. 35 class DIR_Chunk { 36 friend class DebugInformationRecorder; 37 int _offset; // location in the stream of this scope 38 int _length; // number of bytes in the stream 39 int _hash; // hash of stream bytes (for quicker reuse) 40 #if INCLUDE_JVMCI 41 DebugInformationRecorder* _DIR; 42 #endif 43 44 void* operator new(size_t ignore, DebugInformationRecorder* dir) throw() { 45 assert(ignore == sizeof(DIR_Chunk), ""); 46 if (dir->_next_chunk >= dir->_next_chunk_limit) { 47 const int CHUNK = 100; 48 dir->_next_chunk = NEW_RESOURCE_ARRAY(DIR_Chunk, CHUNK); 49 dir->_next_chunk_limit = dir->_next_chunk + CHUNK; 50 } 51 return dir->_next_chunk++; 52 } 53 54 DIR_Chunk(int offset, int length, DebugInformationRecorder* dir) { 55 _offset = offset; 56 _length = length; 57 #if INCLUDE_JVMCI 58 _DIR = dir; 59 #endif 60 unsigned int hash = 0; 61 address p = dir->stream()->buffer() + _offset; 62 for (int i = 0; i < length; i++) { 63 if (i == 6) break; 64 hash *= 127; 65 hash += p[i]; 66 } 67 _hash = hash; 68 } 69 70 DIR_Chunk* find_match(GrowableArray<DIR_Chunk*>* arr, 71 int start_index, 72 DebugInformationRecorder* dir) { 73 int end_index = arr->length(); 74 int hash = this->_hash, length = this->_length; 75 address buf = dir->stream()->buffer(); 76 for (int i = end_index; --i >= start_index; ) { 77 DIR_Chunk* that = arr->at(i); 78 if (hash == that->_hash && 79 length == that->_length && 80 0 == memcmp(buf + this->_offset, buf + that->_offset, length)) { 81 return that; 82 } 83 } 84 return NULL; 85 } 86 87 #if INCLUDE_JVMCI 88 static int compare(DIR_Chunk* const & a, DIR_Chunk* const & b) { 89 if (b->_hash > a->_hash) { 90 return 1; 91 } 92 if (b->_hash < a->_hash) { 93 return -1; 94 } 95 if (b->_length > a->_length) { 96 return 1; 97 } 98 if (b->_length < a->_length) { 99 return -1; 100 } 101 address buf = a->_DIR->stream()->buffer(); 102 return memcmp(buf + b->_offset, buf + a->_offset, a->_length); 103 } 104 #endif 105 }; 106 107 static inline bool compute_recording_non_safepoints() { 108 if (JvmtiExport::should_post_compiled_method_load() 109 && FLAG_IS_DEFAULT(DebugNonSafepoints)) { 110 // The default value of this flag is taken to be true, 111 // if JVMTI is looking at nmethod codes. 112 // We anticipate that JVMTI may wish to participate in profiling. 113 return true; 114 } 115 116 // If the flag is set manually, use it, whether true or false. 117 // Otherwise, if JVMTI is not in the picture, use the default setting. 118 // (This is true in debug, just for the exercise, false in product mode.) 119 return DebugNonSafepoints; 120 } 121 122 DebugInformationRecorder::DebugInformationRecorder(OopRecorder* oop_recorder) 123 : _recording_non_safepoints(compute_recording_non_safepoints()) 124 { 125 _pcs_size = 100; 126 _pcs = NEW_RESOURCE_ARRAY(PcDesc, _pcs_size); 127 _pcs_length = 0; 128 129 _prev_safepoint_pc = PcDesc::lower_offset_limit; 130 131 _stream = new DebugInfoWriteStream(this, 10 * K); 132 // make sure that there is no stream_decode_offset that is zero 133 _stream->write_byte((jbyte)0xFF); 134 135 // make sure that we can distinguish the value "serialized_null" from offsets 136 assert(_stream->position() > serialized_null, "sanity"); 137 138 _oop_recorder = oop_recorder; 139 140 _all_chunks = new GrowableArray<DIR_Chunk*>(300); 141 #if !INCLUDE_JVMCI 142 _shared_chunks = new GrowableArray<DIR_Chunk*>(30); 143 #endif 144 _next_chunk = _next_chunk_limit = NULL; 145 146 add_new_pc_offset(PcDesc::lower_offset_limit); // sentinel record 147 148 debug_only(_recording_state = rs_null); 149 } 150 151 152 void DebugInformationRecorder::add_oopmap(int pc_offset, OopMap* map) { 153 // !!!!! Preserve old style handling of oopmaps for now 154 _oopmaps->add_gc_map(pc_offset, map); 155 } 156 157 void DebugInformationRecorder::add_safepoint(int pc_offset, OopMap* map) { 158 assert(!_oop_recorder->is_complete(), "not frozen yet"); 159 // Store the new safepoint 160 161 // Add the oop map 162 add_oopmap(pc_offset, map); 163 164 add_new_pc_offset(pc_offset); 165 166 assert(_recording_state == rs_null, "nesting of recording calls"); 167 debug_only(_recording_state = rs_safepoint); 168 } 169 170 void DebugInformationRecorder::add_non_safepoint(int pc_offset) { 171 assert(!_oop_recorder->is_complete(), "not frozen yet"); 172 assert(_recording_non_safepoints, "must be recording non-safepoints"); 173 174 add_new_pc_offset(pc_offset); 175 176 assert(_recording_state == rs_null, "nesting of recording calls"); 177 debug_only(_recording_state = rs_non_safepoint); 178 } 179 180 void DebugInformationRecorder::add_new_pc_offset(int pc_offset) { 181 assert(_pcs_length == 0 || last_pc()->pc_offset() < pc_offset, 182 "must specify a new, larger pc offset"); 183 184 // add the pcdesc 185 if (_pcs_length == _pcs_size) { 186 // Expand 187 int new_pcs_size = _pcs_size * 2; 188 PcDesc* new_pcs = NEW_RESOURCE_ARRAY(PcDesc, new_pcs_size); 189 for (int index = 0; index < _pcs_length; index++) { 190 new_pcs[index] = _pcs[index]; 191 } 192 _pcs_size = new_pcs_size; 193 _pcs = new_pcs; 194 } 195 assert(_pcs_size > _pcs_length, "There must be room for after expanding"); 196 197 _pcs[_pcs_length++] = PcDesc(pc_offset, DebugInformationRecorder::serialized_null, 198 DebugInformationRecorder::serialized_null); 199 } 200 201 202 int DebugInformationRecorder::serialize_monitor_values(GrowableArray<MonitorValue*>* monitors) { 203 if (monitors == NULL || monitors->is_empty()) return DebugInformationRecorder::serialized_null; 204 assert(_recording_state == rs_safepoint, "must be recording a safepoint"); 205 int result = stream()->position(); 206 stream()->write_int(monitors->length()); 207 for (int index = 0; index < monitors->length(); index++) { 208 monitors->at(index)->write_on(stream()); 209 } 210 assert(result != serialized_null, "sanity"); 211 212 // (See comment below on DebugInformationRecorder::describe_scope.) 213 int shared_result = find_sharable_decode_offset(result); 214 if (shared_result != serialized_null) { 215 stream()->set_position(result); 216 result = shared_result; 217 } 218 219 return result; 220 } 221 222 223 int DebugInformationRecorder::serialize_scope_values(GrowableArray<ScopeValue*>* values) { 224 if (values == NULL || values->is_empty()) return DebugInformationRecorder::serialized_null; 225 assert(_recording_state == rs_safepoint, "must be recording a safepoint"); 226 int result = stream()->position(); 227 assert(result != serialized_null, "sanity"); 228 stream()->write_int(values->length()); 229 for (int index = 0; index < values->length(); index++) { 230 values->at(index)->write_on(stream()); 231 } 232 233 // (See comment below on DebugInformationRecorder::describe_scope.) 234 int shared_result = find_sharable_decode_offset(result); 235 if (shared_result != serialized_null) { 236 stream()->set_position(result); 237 result = shared_result; 238 } 239 240 return result; 241 } 242 243 244 #ifndef PRODUCT 245 // These variables are put into one block to reduce relocations 246 // and make it simpler to print from the debugger. 247 static 248 struct dir_stats_struct { 249 int chunks_queried; 250 int chunks_shared; 251 int chunks_reshared; 252 int chunks_elided; 253 254 void print() { 255 tty->print_cr("Debug Data Chunks: %d, shared %d+%d, non-SP's elided %d", 256 chunks_queried, 257 chunks_shared, chunks_reshared, 258 chunks_elided); 259 } 260 } dir_stats; 261 #endif //PRODUCT 262 263 264 int DebugInformationRecorder::find_sharable_decode_offset(int stream_offset) { 265 #if !INCLUDE_JVMCI 266 // Only pull this trick if non-safepoint recording 267 // is enabled, for now. 268 if (!recording_non_safepoints()) { 269 return serialized_null; 270 } 271 #endif // INCLUDE_JVMCI 272 273 NOT_PRODUCT(++dir_stats.chunks_queried); 274 int stream_length = stream()->position() - stream_offset; 275 assert(stream_offset != serialized_null, "should not be null"); 276 assert(stream_length != 0, "should not be empty"); 277 278 DIR_Chunk* ns = new(this) DIR_Chunk(stream_offset, stream_length, this); 279 280 #if INCLUDE_JVMCI 281 DIR_Chunk* match = _all_chunks->insert_sorted<DIR_Chunk::compare>(ns); 282 if (match != ns) { 283 // Found an existing chunk 284 NOT_PRODUCT(++dir_stats.chunks_shared); 285 assert(ns+1 == _next_chunk, ""); 286 _next_chunk = ns; 287 return match->_offset; 288 } else { 289 // Inserted this chunk, so nothing to do 290 return serialized_null; 291 } 292 #else // INCLUDE_JVMCI 293 // Look in previously shared scopes first: 294 DIR_Chunk* ms = ns->find_match(_shared_chunks, 0, this); 295 if (ms != NULL) { 296 NOT_PRODUCT(++dir_stats.chunks_reshared); 297 assert(ns+1 == _next_chunk, ""); 298 _next_chunk = ns; 299 return ms->_offset; 300 } 301 302 // Look in recently encountered scopes next: 303 const int MAX_RECENT = 50; 304 int start_index = _all_chunks->length() - MAX_RECENT; 305 if (start_index < 0) start_index = 0; 306 ms = ns->find_match(_all_chunks, start_index, this); 307 if (ms != NULL) { 308 NOT_PRODUCT(++dir_stats.chunks_shared); 309 // Searching in _all_chunks is limited to a window, 310 // but searching in _shared_chunks is unlimited. 311 _shared_chunks->append(ms); 312 assert(ns+1 == _next_chunk, ""); 313 _next_chunk = ns; 314 return ms->_offset; 315 } 316 317 // No match. Add this guy to the list, in hopes of future shares. 318 _all_chunks->append(ns); 319 return serialized_null; 320 #endif // INCLUDE_JVMCI 321 } 322 323 324 // must call add_safepoint before: it sets PcDesc and this routine uses 325 // the last PcDesc set 326 void DebugInformationRecorder::describe_scope(int pc_offset, 327 methodHandle methodH, 328 ciMethod* method, 329 int bci, 330 bool reexecute, 331 bool rethrow_exception, 332 bool is_method_handle_invoke, 333 bool return_oop, 334 DebugToken* locals, 335 DebugToken* expressions, 336 DebugToken* monitors) { 337 assert(_recording_state != rs_null, "nesting of recording calls"); 338 PcDesc* last_pd = last_pc(); 339 assert(last_pd->pc_offset() == pc_offset, "must be last pc"); 340 int sender_stream_offset = last_pd->scope_decode_offset(); 341 // update the stream offset of current pc desc 342 int stream_offset = stream()->position(); 343 last_pd->set_scope_decode_offset(stream_offset); 344 345 // Record flags into pcDesc. 346 last_pd->set_should_reexecute(reexecute); 347 last_pd->set_rethrow_exception(rethrow_exception); 348 last_pd->set_is_method_handle_invoke(is_method_handle_invoke); 349 last_pd->set_return_oop(return_oop); 350 351 // serialize sender stream offest 352 stream()->write_int(sender_stream_offset); 353 354 // serialize scope 355 Metadata* method_enc; 356 if (method != NULL) { 357 method_enc = method->constant_encoding(); 358 } else if (methodH.not_null()) { 359 method_enc = methodH(); 360 } else { 361 method_enc = NULL; 362 } 363 int method_enc_index = oop_recorder()->find_index(method_enc); 364 stream()->write_int(method_enc_index); 365 stream()->write_bci(bci); 366 assert(method == NULL || 367 (method->is_native() && bci == 0) || 368 (!method->is_native() && 0 <= bci && bci < method->code_size()) || 369 (method->is_compiled_lambda_form() && bci == -99) || // this might happen in C1 370 bci == -1, "illegal bci"); 371 372 // serialize the locals/expressions/monitors 373 stream()->write_int((intptr_t) locals); 374 stream()->write_int((intptr_t) expressions); 375 stream()->write_int((intptr_t) monitors); 376 377 // Here's a tricky bit. We just wrote some bytes. 378 // Wouldn't it be nice to find that we had already 379 // written those same bytes somewhere else? 380 // If we get lucky this way, reset the stream 381 // and reuse the old bytes. By the way, this 382 // trick not only shares parent scopes, but also 383 // compresses equivalent non-safepoint PcDescs. 384 int shared_stream_offset = find_sharable_decode_offset(stream_offset); 385 if (shared_stream_offset != serialized_null) { 386 stream()->set_position(stream_offset); 387 last_pd->set_scope_decode_offset(shared_stream_offset); 388 } 389 } 390 391 void DebugInformationRecorder::dump_object_pool(GrowableArray<ScopeValue*>* objects) { 392 guarantee( _pcs_length > 0, "safepoint must exist before describing scopes"); 393 PcDesc* last_pd = &_pcs[_pcs_length-1]; 394 if (objects != NULL) { 395 for (int i = objects->length() - 1; i >= 0; i--) { 396 objects->at(i)->as_ObjectValue()->set_visited(false); 397 } 398 } 399 int offset = serialize_scope_values(objects); 400 last_pd->set_obj_decode_offset(offset); 401 } 402 403 void DebugInformationRecorder::end_scopes(int pc_offset, bool is_safepoint) { 404 assert(_recording_state == (is_safepoint? rs_safepoint: rs_non_safepoint), 405 "nesting of recording calls"); 406 debug_only(_recording_state = rs_null); 407 408 // Try to compress away an equivalent non-safepoint predecessor. 409 // (This only works because we have previously recognized redundant 410 // scope trees and made them use a common scope_decode_offset.) 411 if (_pcs_length >= 2 && recording_non_safepoints()) { 412 PcDesc* last = last_pc(); 413 PcDesc* prev = prev_pc(); 414 // If prev is (a) not a safepoint and (b) has the same 415 // stream pointer, then it can be coalesced into the last. 416 // This is valid because non-safepoints are only sought 417 // with pc_desc_near, which (when it misses prev) will 418 // search forward until it finds last. 419 // In addition, it does not matter if the last PcDesc 420 // is for a safepoint or not. 421 if (_prev_safepoint_pc < prev->pc_offset() && prev->is_same_info(last)) { 422 assert(prev == last-1, "sane"); 423 prev->set_pc_offset(pc_offset); 424 _pcs_length -= 1; 425 NOT_PRODUCT(++dir_stats.chunks_elided); 426 } 427 } 428 429 // We have just recorded this safepoint. 430 // Remember it in case the previous paragraph needs to know. 431 if (is_safepoint) { 432 _prev_safepoint_pc = pc_offset; 433 } 434 } 435 436 #ifdef ASSERT 437 bool DebugInformationRecorder::recorders_frozen() { 438 return _oop_recorder->is_complete() || _oop_recorder->is_complete(); 439 } 440 441 void DebugInformationRecorder::mark_recorders_frozen() { 442 _oop_recorder->freeze(); 443 } 444 #endif // PRODUCT 445 446 DebugToken* DebugInformationRecorder::create_scope_values(GrowableArray<ScopeValue*>* values) { 447 assert(!recorders_frozen(), "not frozen yet"); 448 return (DebugToken*) (intptr_t) serialize_scope_values(values); 449 } 450 451 452 DebugToken* DebugInformationRecorder::create_monitor_values(GrowableArray<MonitorValue*>* monitors) { 453 assert(!recorders_frozen(), "not frozen yet"); 454 return (DebugToken*) (intptr_t) serialize_monitor_values(monitors); 455 } 456 457 458 int DebugInformationRecorder::data_size() { 459 debug_only(mark_recorders_frozen()); // mark it "frozen" for asserts 460 return _stream->position(); 461 } 462 463 464 int DebugInformationRecorder::pcs_size() { 465 debug_only(mark_recorders_frozen()); // mark it "frozen" for asserts 466 if (last_pc()->pc_offset() != PcDesc::upper_offset_limit) 467 add_new_pc_offset(PcDesc::upper_offset_limit); 468 return _pcs_length * sizeof(PcDesc); 469 } 470 471 472 void DebugInformationRecorder::copy_to(nmethod* nm) { 473 nm->copy_scopes_data(stream()->buffer(), stream()->position()); 474 nm->copy_scopes_pcs(_pcs, _pcs_length); 475 } 476 477 478 void DebugInformationRecorder::verify(const nmethod* code) { 479 Unimplemented(); 480 } 481 482 #ifndef PRODUCT 483 void DebugInformationRecorder::print_statistics() { 484 dir_stats.print(); 485 } 486 #endif //PRODUCT