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