1 /* 2 * Copyright (c) 2020, 2024, 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 "classfile/classFileParser.hpp" 27 #include "classfile/fieldLayoutBuilder.hpp" 28 #include "classfile/systemDictionary.hpp" 29 #include "classfile/vmSymbols.hpp" 30 #include "jvm.h" 31 #include "memory/resourceArea.hpp" 32 #include "oops/array.hpp" 33 #include "oops/fieldStreams.inline.hpp" 34 #include "oops/instanceMirrorKlass.hpp" 35 #include "oops/instanceKlass.inline.hpp" 36 #include "oops/klass.inline.hpp" 37 #include "oops/inlineKlass.inline.hpp" 38 #include "runtime/fieldDescriptor.inline.hpp" 39 40 LayoutRawBlock::LayoutRawBlock(Kind kind, int size) : 41 _next_block(nullptr), 42 _prev_block(nullptr), 43 _inline_klass(nullptr), 44 _kind(kind), 45 _offset(-1), 46 _alignment(1), 47 _size(size), 48 _field_index(-1), 49 _null_marker_offset(-1), 50 _is_reference(false), 51 _needs_null_marker(false) { 52 assert(kind == EMPTY || kind == RESERVED || kind == PADDING || kind == INHERITED || kind == NULL_MARKER, 53 "Otherwise, should use the constructor with a field index argument"); 54 assert(size > 0, "Sanity check"); 55 } 56 57 58 LayoutRawBlock::LayoutRawBlock(int index, Kind kind, int size, int alignment, bool is_reference) : 59 _next_block(nullptr), 60 _prev_block(nullptr), 61 _inline_klass(nullptr), 62 _kind(kind), 63 _offset(-1), 64 _alignment(alignment), 65 _size(size), 66 _field_index(index), 67 _null_marker_offset(-1), 68 _is_reference(is_reference), 69 _needs_null_marker(false) { 70 assert(kind == REGULAR || kind == FLAT || kind == INHERITED || kind == INHERITED_NULL_MARKER, 71 "Other kind do not have a field index"); 72 assert(size > 0, "Sanity check"); 73 assert(alignment > 0, "Sanity check"); 74 } 75 76 bool LayoutRawBlock::fit(int size, int alignment) { 77 int adjustment = 0; 78 if ((_offset % alignment) != 0) { 79 adjustment = alignment - (_offset % alignment); 80 } 81 return _size >= size + adjustment; 82 } 83 84 FieldGroup::FieldGroup(int contended_group) : 85 _next(nullptr), 86 _small_primitive_fields(nullptr), 87 _big_primitive_fields(nullptr), 88 _oop_fields(nullptr), 89 _contended_group(contended_group), // -1 means no contended group, 0 means default contended group 90 _oop_count(0) {} 91 92 void FieldGroup::add_primitive_field(int idx, BasicType type) { 93 int size = type2aelembytes(type); 94 LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::REGULAR, size, size /* alignment == size for primitive types */, false); 95 if (size >= oopSize) { 96 add_to_big_primitive_list(block); 97 } else { 98 add_to_small_primitive_list(block); 99 } 100 } 101 102 void FieldGroup::add_oop_field(int idx) { 103 int size = type2aelembytes(T_OBJECT); 104 LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::REGULAR, size, size /* alignment == size for oops */, true); 105 if (_oop_fields == nullptr) { 106 _oop_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE); 107 } 108 _oop_fields->append(block); 109 _oop_count++; 110 } 111 112 void FieldGroup::add_flat_field(int idx, InlineKlass* vk, bool needs_null_marker) { 113 LayoutRawBlock* block = new LayoutRawBlock(idx, LayoutRawBlock::FLAT, vk->get_payload_size_in_bytes(), vk->get_alignment(), false); 114 block->set_inline_klass(vk); 115 if (needs_null_marker) block->set_needs_null_marker(); 116 if (block->size() >= oopSize) { 117 add_to_big_primitive_list(block); 118 } else { 119 add_to_small_primitive_list(block); 120 } 121 } 122 123 void FieldGroup::sort_by_size() { 124 if (_small_primitive_fields != nullptr) { 125 _small_primitive_fields->sort(LayoutRawBlock::compare_size_inverted); 126 } 127 if (_big_primitive_fields != nullptr) { 128 _big_primitive_fields->sort(LayoutRawBlock::compare_size_inverted); 129 } 130 } 131 132 void FieldGroup::add_to_small_primitive_list(LayoutRawBlock* block) { 133 if (_small_primitive_fields == nullptr) { 134 _small_primitive_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE); 135 } 136 _small_primitive_fields->append(block); 137 } 138 139 void FieldGroup::add_to_big_primitive_list(LayoutRawBlock* block) { 140 if (_big_primitive_fields == nullptr) { 141 _big_primitive_fields = new GrowableArray<LayoutRawBlock*>(INITIAL_LIST_SIZE); 142 } 143 _big_primitive_fields->append(block); 144 } 145 146 FieldLayout::FieldLayout(GrowableArray<FieldInfo>* field_info, ConstantPool* cp) : 147 _field_info(field_info), 148 _cp(cp), 149 _blocks(nullptr), 150 _start(_blocks), 151 _last(_blocks), 152 _super_first_field_offset(-1), 153 _super_alignment(-1), 154 _super_min_align_required(-1), 155 _super_has_fields(false), 156 _has_missing_null_markers(false) {} 157 158 void FieldLayout::initialize_static_layout() { 159 _blocks = new LayoutRawBlock(LayoutRawBlock::EMPTY, INT_MAX); 160 _blocks->set_offset(0); 161 _last = _blocks; 162 _start = _blocks; 163 // Note: at this stage, InstanceMirrorKlass::offset_of_static_fields() could be zero, because 164 // during bootstrapping, the size of the java.lang.Class is still not known when layout 165 // of static field is computed. Field offsets are fixed later when the size is known 166 // (see java_lang_Class::fixup_mirror()) 167 if (InstanceMirrorKlass::offset_of_static_fields() > 0) { 168 insert(first_empty_block(), new LayoutRawBlock(LayoutRawBlock::RESERVED, InstanceMirrorKlass::offset_of_static_fields())); 169 _blocks->set_offset(0); 170 } 171 } 172 173 void FieldLayout::initialize_instance_layout(const InstanceKlass* super_klass) { 174 if (super_klass == nullptr) { 175 _blocks = new LayoutRawBlock(LayoutRawBlock::EMPTY, INT_MAX); 176 _blocks->set_offset(0); 177 _last = _blocks; 178 _start = _blocks; 179 insert(first_empty_block(), new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes())); 180 } else { 181 _super_has_fields = reconstruct_layout(super_klass); 182 fill_holes(super_klass); 183 if ((UseEmptySlotsInSupers && !super_klass->has_contended_annotations()) || !_super_has_fields) { 184 _start = _blocks; // Setting _start to _blocks instead of _last would allow subclasses 185 // to allocate fields in empty slots of their super classes 186 } else { 187 _start = _last; // append fields at the end of the reconstructed layout 188 } 189 } 190 } 191 192 LayoutRawBlock* FieldLayout::first_field_block() { 193 LayoutRawBlock* block = _blocks; 194 while (block != nullptr 195 && block->kind() != LayoutRawBlock::INHERITED 196 && block->kind() != LayoutRawBlock::REGULAR 197 && block->kind() != LayoutRawBlock::FLAT) { 198 block = block->next_block(); 199 } 200 return block; 201 } 202 203 // Insert a set of fields into a layout. 204 // For each field, search for an empty slot able to fit the field 205 // (satisfying both size and alignment requirements), if none is found, 206 // add the field at the end of the layout. 207 // Fields cannot be inserted before the block specified in the "start" argument 208 void FieldLayout::add(GrowableArray<LayoutRawBlock*>* list, LayoutRawBlock* start) { 209 if (list == nullptr) return; 210 if (start == nullptr) start = this->_start; 211 bool last_search_success = false; 212 int last_size = 0; 213 int last_alignment = 0; 214 for (int i = 0; i < list->length(); i ++) { 215 LayoutRawBlock* b = list->at(i); 216 LayoutRawBlock* cursor = nullptr; 217 LayoutRawBlock* candidate = nullptr; 218 // if start is the last block, just append the field 219 if (start == last_block()) { 220 candidate = last_block(); 221 } 222 // Before iterating over the layout to find an empty slot fitting the field's requirements, 223 // check if the previous field had the same requirements and if the search for a fitting slot 224 // was successful. If the requirements were the same but the search failed, a new search will 225 // fail the same way, so just append the field at the of the layout. 226 else if (b->size() == last_size && b->alignment() == last_alignment && !last_search_success) { 227 candidate = last_block(); 228 } else { 229 // Iterate over the layout to find an empty slot fitting the field's requirements 230 last_size = b->size(); 231 last_alignment = b->alignment(); 232 cursor = last_block()->prev_block(); 233 assert(cursor != nullptr, "Sanity check"); 234 last_search_success = true; 235 236 while (cursor != start) { 237 if (cursor->kind() == LayoutRawBlock::EMPTY && cursor->fit(b->size(), b->alignment())) { 238 if (candidate == nullptr || cursor->size() < candidate->size()) { 239 candidate = cursor; 240 } 241 } 242 cursor = cursor->prev_block(); 243 } 244 if (candidate == nullptr) { 245 candidate = last_block(); 246 last_search_success = false; 247 } 248 assert(candidate != nullptr, "Candidate must not be null"); 249 assert(candidate->kind() == LayoutRawBlock::EMPTY, "Candidate must be an empty block"); 250 assert(candidate->fit(b->size(), b->alignment()), "Candidate must be able to store the block"); 251 } 252 insert_field_block(candidate, b); 253 } 254 } 255 256 // Used for classes with hard coded field offsets, insert a field at the specified offset */ 257 void FieldLayout::add_field_at_offset(LayoutRawBlock* block, int offset, LayoutRawBlock* start) { 258 assert(block != nullptr, "Sanity check"); 259 block->set_offset(offset); 260 if (start == nullptr) { 261 start = this->_start; 262 } 263 LayoutRawBlock* slot = start; 264 while (slot != nullptr) { 265 if ((slot->offset() <= block->offset() && (slot->offset() + slot->size()) > block->offset()) || 266 slot == _last){ 267 assert(slot->kind() == LayoutRawBlock::EMPTY, "Matching slot must be an empty slot"); 268 assert(slot->size() >= block->offset() - slot->offset() + block->size() ,"Matching slot must be big enough"); 269 if (slot->offset() < block->offset()) { 270 int adjustment = block->offset() - slot->offset(); 271 LayoutRawBlock* adj = new LayoutRawBlock(LayoutRawBlock::EMPTY, adjustment); 272 insert(slot, adj); 273 } 274 insert(slot, block); 275 if (slot->size() == 0) { 276 remove(slot); 277 } 278 if (block->kind() == LayoutRawBlock::REGULAR || block->kind() == LayoutRawBlock::FLAT) { 279 _field_info->adr_at(block->field_index())->set_offset(block->offset()); 280 } 281 return; 282 } 283 slot = slot->next_block(); 284 } 285 fatal("Should have found a matching slot above, corrupted layout or invalid offset"); 286 } 287 288 // The allocation logic uses a best fit strategy: the set of fields is allocated 289 // in the first empty slot big enough to contain the whole set ((including padding 290 // to fit alignment constraints). 291 void FieldLayout::add_contiguously(GrowableArray<LayoutRawBlock*>* list, LayoutRawBlock* start) { 292 if (list == nullptr) return; 293 if (start == nullptr) { 294 start = _start; 295 } 296 // This code assumes that if the first block is well aligned, the following 297 // blocks would naturally be well aligned (no need for adjustment) 298 int size = 0; 299 for (int i = 0; i < list->length(); i++) { 300 size += list->at(i)->size(); 301 } 302 303 LayoutRawBlock* candidate = nullptr; 304 if (start == last_block()) { 305 candidate = last_block(); 306 } else { 307 LayoutRawBlock* first = list->at(0); 308 candidate = last_block()->prev_block(); 309 while (candidate->kind() != LayoutRawBlock::EMPTY || !candidate->fit(size, first->alignment())) { 310 if (candidate == start) { 311 candidate = last_block(); 312 break; 313 } 314 candidate = candidate->prev_block(); 315 } 316 assert(candidate != nullptr, "Candidate must not be null"); 317 assert(candidate->kind() == LayoutRawBlock::EMPTY, "Candidate must be an empty block"); 318 assert(candidate->fit(size, first->alignment()), "Candidate must be able to store the whole contiguous block"); 319 } 320 321 for (int i = 0; i < list->length(); i++) { 322 LayoutRawBlock* b = list->at(i); 323 insert_field_block(candidate, b); 324 assert((candidate->offset() % b->alignment() == 0), "Contiguous blocks must be naturally well aligned"); 325 } 326 } 327 328 LayoutRawBlock* FieldLayout::insert_field_block(LayoutRawBlock* slot, LayoutRawBlock* block) { 329 assert(slot->kind() == LayoutRawBlock::EMPTY, "Blocks can only be inserted in empty blocks"); 330 if (slot->offset() % block->alignment() != 0) { 331 int adjustment = block->alignment() - (slot->offset() % block->alignment()); 332 LayoutRawBlock* adj = new LayoutRawBlock(LayoutRawBlock::EMPTY, adjustment); 333 insert(slot, adj); 334 } 335 assert(block->size() >= block->size(), "Enough space must remain afte adjustment"); 336 insert(slot, block); 337 if (block->needs_null_marker()) { 338 _has_missing_null_markers = true; 339 } 340 if (slot->size() == 0) { 341 remove(slot); 342 } 343 // NULL_MARKER blocks have a field index pointing to the field that needs a null marker, 344 // so the field_info at this index must not be updated with the null marker's offset 345 if (block->kind() != LayoutRawBlock::NULL_MARKER) { 346 _field_info->adr_at(block->field_index())->set_offset(block->offset()); 347 } 348 return block; 349 } 350 351 bool FieldLayout::reconstruct_layout(const InstanceKlass* ik) { 352 bool has_instance_fields = false; 353 if (ik->is_abstract() && !ik->is_identity_class()) { 354 _super_alignment = type2aelembytes(BasicType::T_LONG); 355 } 356 GrowableArray<LayoutRawBlock*>* all_fields = new GrowableArray<LayoutRawBlock*>(32); 357 while (ik != nullptr) { 358 for (AllFieldStream fs(ik->fieldinfo_stream(), ik->constants()); !fs.done(); fs.next()) { 359 BasicType type = Signature::basic_type(fs.signature()); 360 // distinction between static and non-static fields is missing 361 if (fs.access_flags().is_static()) continue; 362 has_instance_fields = true; 363 if (_super_first_field_offset == -1 || fs.offset() < _super_first_field_offset) _super_first_field_offset = fs.offset(); 364 LayoutRawBlock* block; 365 if (fs.is_flat()) { 366 InlineKlass* vk = InlineKlass::cast(ik->get_inline_type_field_klass(fs.index())); 367 block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED, vk->get_payload_size_in_bytes(), 368 vk->get_alignment(), false); 369 assert(_super_alignment == -1 || _super_alignment >= vk->get_alignment(), "Invalid value alignment"); 370 _super_min_align_required = _super_min_align_required > vk->get_alignment() ? _super_min_align_required : vk->get_alignment(); 371 if (!fs.field_flags().is_null_free_inline_type()) { 372 assert(fs.field_flags().has_null_marker(), "Nullable flat fields must have a null marker"); 373 LayoutRawBlock* marker = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED_NULL_MARKER, 1 /* current NULL_MARKER block are one byte */, 374 1, false); 375 marker->set_offset(fs.null_marker_offset()); 376 all_fields->append(marker); 377 } 378 } else { 379 int size = type2aelembytes(type); 380 // INHERITED blocks are marked as non-reference because oop_maps are handled by their holder class 381 block = new LayoutRawBlock(fs.index(), LayoutRawBlock::INHERITED, size, size, false); 382 // For primitive types, the alignment is equal to the size 383 assert(_super_alignment == -1 || _super_alignment >= size, "Invalid value alignment"); 384 _super_min_align_required = _super_min_align_required > size ? _super_min_align_required : size; 385 } 386 block->set_offset(fs.offset()); 387 all_fields->append(block); 388 } 389 ik = ik->super() == nullptr ? nullptr : InstanceKlass::cast(ik->super()); 390 } 391 all_fields->sort(LayoutRawBlock::compare_offset); 392 _blocks = new LayoutRawBlock(LayoutRawBlock::RESERVED, instanceOopDesc::base_offset_in_bytes()); 393 _blocks->set_offset(0); 394 _last = _blocks; 395 for(int i = 0; i < all_fields->length(); i++) { 396 LayoutRawBlock* b = all_fields->at(i); 397 _last->set_next_block(b); 398 b->set_prev_block(_last); 399 _last = b; 400 } 401 _start = _blocks; 402 return has_instance_fields; 403 } 404 405 // Called during the reconstruction of a layout, after fields from super 406 // classes have been inserted. It fills unused slots between inserted fields 407 // with EMPTY blocks, so the regular field insertion methods would work. 408 // This method handles classes with @Contended annotations differently 409 // by inserting PADDING blocks instead of EMPTY block to prevent subclasses' 410 // fields to interfere with contended fields/classes. 411 void FieldLayout::fill_holes(const InstanceKlass* super_klass) { 412 assert(_blocks != nullptr, "Sanity check"); 413 assert(_blocks->offset() == 0, "first block must be at offset zero"); 414 LayoutRawBlock::Kind filling_type = super_klass->has_contended_annotations() ? LayoutRawBlock::PADDING: LayoutRawBlock::EMPTY; 415 LayoutRawBlock* b = _blocks; 416 while (b->next_block() != nullptr) { 417 if (b->next_block()->offset() > (b->offset() + b->size())) { 418 int size = b->next_block()->offset() - (b->offset() + b->size()); 419 LayoutRawBlock* empty = new LayoutRawBlock(filling_type, size); 420 empty->set_offset(b->offset() + b->size()); 421 empty->set_next_block(b->next_block()); 422 b->next_block()->set_prev_block(empty); 423 b->set_next_block(empty); 424 empty->set_prev_block(b); 425 } 426 b = b->next_block(); 427 } 428 assert(b->next_block() == nullptr, "Invariant at this point"); 429 assert(b->kind() != LayoutRawBlock::EMPTY, "Sanity check"); 430 // If the super class has @Contended annotation, a padding block is 431 // inserted at the end to ensure that fields from the subclasses won't share 432 // the cache line of the last field of the contended class 433 if (super_klass->has_contended_annotations() && ContendedPaddingWidth > 0) { 434 LayoutRawBlock* p = new LayoutRawBlock(LayoutRawBlock::PADDING, ContendedPaddingWidth); 435 p->set_offset(b->offset() + b->size()); 436 b->set_next_block(p); 437 p->set_prev_block(b); 438 b = p; 439 } 440 if (!UseEmptySlotsInSupers) { 441 // Add an empty slots to align fields of the subclass on a heapOopSize boundary 442 // in order to emulate the behavior of the previous algorithm 443 int align = (b->offset() + b->size()) % heapOopSize; 444 if (align != 0) { 445 int sz = heapOopSize - align; 446 LayoutRawBlock* p = new LayoutRawBlock(LayoutRawBlock::EMPTY, sz); 447 p->set_offset(b->offset() + b->size()); 448 b->set_next_block(p); 449 p->set_prev_block(b); 450 b = p; 451 } 452 } 453 LayoutRawBlock* last = new LayoutRawBlock(LayoutRawBlock::EMPTY, INT_MAX); 454 last->set_offset(b->offset() + b->size()); 455 assert(last->offset() > 0, "Sanity check"); 456 b->set_next_block(last); 457 last->set_prev_block(b); 458 _last = last; 459 } 460 461 LayoutRawBlock* FieldLayout::insert(LayoutRawBlock* slot, LayoutRawBlock* block) { 462 assert(slot->kind() == LayoutRawBlock::EMPTY, "Blocks can only be inserted in empty blocks"); 463 assert(slot->offset() % block->alignment() == 0, "Incompatible alignment"); 464 block->set_offset(slot->offset()); 465 slot->set_offset(slot->offset() + block->size()); 466 assert((slot->size() - block->size()) < slot->size(), "underflow checking"); 467 assert(slot->size() - block->size() >= 0, "no negative size allowed"); 468 slot->set_size(slot->size() - block->size()); 469 block->set_prev_block(slot->prev_block()); 470 block->set_next_block(slot); 471 slot->set_prev_block(block); 472 if (block->prev_block() != nullptr) { 473 block->prev_block()->set_next_block(block); 474 } 475 if (_blocks == slot) { 476 _blocks = block; 477 } 478 if (_start == slot) { 479 _start = block; 480 } 481 return block; 482 } 483 484 void FieldLayout::remove(LayoutRawBlock* block) { 485 assert(block != nullptr, "Sanity check"); 486 assert(block != _last, "Sanity check"); 487 if (_blocks == block) { 488 _blocks = block->next_block(); 489 if (_blocks != nullptr) { 490 _blocks->set_prev_block(nullptr); 491 } 492 } else { 493 assert(block->prev_block() != nullptr, "_prev should be set for non-head blocks"); 494 block->prev_block()->set_next_block(block->next_block()); 495 block->next_block()->set_prev_block(block->prev_block()); 496 } 497 if (block == _start) { 498 _start = block->prev_block(); 499 } 500 } 501 502 void FieldLayout::print(outputStream* output, bool is_static, const InstanceKlass* super, Array<InlineKlass*>* inline_fields) { 503 ResourceMark rm; 504 LayoutRawBlock* b = _blocks; 505 while(b != _last) { 506 switch(b->kind()) { 507 case LayoutRawBlock::REGULAR: { 508 FieldInfo* fi = _field_info->adr_at(b->field_index()); 509 output->print_cr(" @%d %s %d/%d \"%s\" %s", 510 b->offset(), 511 "REGULAR", 512 b->size(), 513 b->alignment(), 514 fi->name(_cp)->as_C_string(), 515 fi->signature(_cp)->as_C_string()); 516 break; 517 } 518 case LayoutRawBlock::FLAT: { 519 FieldInfo* fi = _field_info->adr_at(b->field_index()); 520 InlineKlass* ik = inline_fields->at(fi->index()); 521 assert(ik != nullptr, ""); 522 output->print(" @%d %s %d/%d \"%s\" %s %s@%p", 523 b->offset(), 524 "FLAT", 525 b->size(), 526 b->alignment(), 527 fi->name(_cp)->as_C_string(), 528 fi->signature(_cp)->as_C_string(), 529 ik->name()->as_C_string(), 530 ik->class_loader_data()); 531 if (fi->field_flags().has_null_marker()) { 532 output->print_cr(" null marker offset %d %s", fi->null_marker_offset(), 533 fi->field_flags().is_null_marker_internal() ? "(internal)" : ""); 534 } else { 535 output->print_cr(""); 536 } 537 break; 538 } 539 case LayoutRawBlock::RESERVED: { 540 output->print_cr(" @%d %s %d/-", 541 b->offset(), 542 "RESERVED", 543 b->size()); 544 break; 545 } 546 case LayoutRawBlock::INHERITED: { 547 assert(!is_static, "Static fields are not inherited in layouts"); 548 assert(super != nullptr, "super klass must be provided to retrieve inherited fields info"); 549 bool found = false; 550 const InstanceKlass* ik = super; 551 while (!found && ik != nullptr) { 552 for (AllFieldStream fs(ik->fieldinfo_stream(), ik->constants()); !fs.done(); fs.next()) { 553 if (fs.offset() == b->offset() && fs.access_flags().is_static() == is_static) { 554 output->print_cr(" @%d %s %d/%d \"%s\" %s", 555 b->offset(), 556 "INHERITED", 557 b->size(), 558 b->size(), // so far, alignment constraint == size, will change with Valhalla => FIXME 559 fs.name()->as_C_string(), 560 fs.signature()->as_C_string()); 561 found = true; 562 break; 563 } 564 } 565 ik = ik->java_super(); 566 } 567 break; 568 } 569 case LayoutRawBlock::INHERITED_NULL_MARKER : 570 output->print_cr(" @%d %s %d/1", 571 b->offset(), 572 "INHERITED_NULL_MARKER", 573 b->size()); 574 break; 575 case LayoutRawBlock::EMPTY: 576 output->print_cr(" @%d %s %d/1", 577 b->offset(), 578 "EMPTY", 579 b->size()); 580 break; 581 case LayoutRawBlock::PADDING: 582 output->print_cr(" @%d %s %d/1", 583 b->offset(), 584 "PADDING", 585 b->size()); 586 break; 587 case LayoutRawBlock::NULL_MARKER: 588 { 589 FieldInfo* fi = _field_info->adr_at(b->field_index()); 590 output->print_cr(" @%d %s %d/1 null marker for field at offset %d", 591 b->offset(), 592 "NULL_MARKER", 593 b->size(), 594 fi->offset()); 595 break; 596 } 597 default: 598 fatal("Unknown block type"); 599 } 600 b = b->next_block(); 601 } 602 } 603 604 FieldLayoutBuilder::FieldLayoutBuilder(const Symbol* classname, ClassLoaderData* loader_data, const InstanceKlass* super_klass, ConstantPool* constant_pool, 605 GrowableArray<FieldInfo>* field_info, bool is_contended, bool is_inline_type,bool is_abstract_value, 606 FieldLayoutInfo* info, Array<InlineKlass*>* inline_type_field_klasses) : 607 _classname(classname), 608 _loader_data(loader_data), 609 _super_klass(super_klass), 610 _constant_pool(constant_pool), 611 _field_info(field_info), 612 _info(info), 613 _inline_type_field_klasses(inline_type_field_klasses), 614 _root_group(nullptr), 615 _contended_groups(GrowableArray<FieldGroup*>(8)), 616 _static_fields(nullptr), 617 _layout(nullptr), 618 _static_layout(nullptr), 619 _nonstatic_oopmap_count(0), 620 _alignment(-1), 621 _first_field_offset(-1), 622 _internal_null_marker_offset(-1), 623 _payload_size_in_bytes(-1), 624 _atomic_field_count(0), 625 _fields_size_sum(0), 626 _has_nonstatic_fields(false), 627 _has_inline_type_fields(false), 628 _is_contended(is_contended), 629 _is_inline_type(is_inline_type), 630 _is_abstract_value(is_abstract_value), 631 _has_flattening_information(is_inline_type), 632 _has_nonatomic_values(false), 633 _nullable_atomic_flat_candidate(false), 634 _has_null_markers(false) {} 635 636 FieldGroup* FieldLayoutBuilder::get_or_create_contended_group(int g) { 637 assert(g > 0, "must only be called for named contended groups"); 638 FieldGroup* fg = nullptr; 639 for (int i = 0; i < _contended_groups.length(); i++) { 640 fg = _contended_groups.at(i); 641 if (fg->contended_group() == g) return fg; 642 } 643 fg = new FieldGroup(g); 644 _contended_groups.append(fg); 645 return fg; 646 } 647 648 void FieldLayoutBuilder::prologue() { 649 _layout = new FieldLayout(_field_info, _constant_pool); 650 const InstanceKlass* super_klass = _super_klass; 651 _layout->initialize_instance_layout(super_klass); 652 if (super_klass != nullptr) { 653 _has_nonstatic_fields = super_klass->has_nonstatic_fields(); 654 } 655 _static_layout = new FieldLayout(_field_info, _constant_pool); 656 _static_layout->initialize_static_layout(); 657 _static_fields = new FieldGroup(); 658 _root_group = new FieldGroup(); 659 } 660 661 // Field sorting for regular (non-inline) classes: 662 // - fields are sorted in static and non-static fields 663 // - non-static fields are also sorted according to their contention group 664 // (support of the @Contended annotation) 665 // - @Contended annotation is ignored for static fields 666 // - field flattening decisions are taken in this method 667 void FieldLayoutBuilder::regular_field_sorting() { 668 int idx = 0; 669 for (GrowableArrayIterator<FieldInfo> it = _field_info->begin(); it != _field_info->end(); ++it, ++idx) { 670 FieldGroup* group = nullptr; 671 FieldInfo fieldinfo = *it; 672 if (fieldinfo.access_flags().is_static()) { 673 group = _static_fields; 674 } else { 675 _has_nonstatic_fields = true; 676 _atomic_field_count++; // we might decrement this 677 if (fieldinfo.field_flags().is_contended()) { 678 int g = fieldinfo.contended_group(); 679 if (g == 0) { 680 group = new FieldGroup(true); 681 _contended_groups.append(group); 682 } else { 683 group = get_or_create_contended_group(g); 684 } 685 } else { 686 group = _root_group; 687 } 688 } 689 assert(group != nullptr, "invariant"); 690 BasicType type = Signature::basic_type(fieldinfo.signature(_constant_pool)); 691 switch(type) { 692 case T_BYTE: 693 case T_CHAR: 694 case T_DOUBLE: 695 case T_FLOAT: 696 case T_INT: 697 case T_LONG: 698 case T_SHORT: 699 case T_BOOLEAN: 700 group->add_primitive_field(idx, type); 701 break; 702 case T_OBJECT: 703 case T_ARRAY: 704 { 705 bool field_is_known_value_class = !fieldinfo.field_flags().is_injected() && _inline_type_field_klasses != nullptr && _inline_type_field_klasses->at(fieldinfo.index()) != nullptr; 706 bool value_has_oops = field_is_known_value_class ? _inline_type_field_klasses->at(fieldinfo.index())->nonstatic_oop_count() > 0 : true; 707 bool is_candidate_for_flattening = fieldinfo.field_flags().is_null_free_inline_type() || (EnableNullableFieldFlattening && field_is_known_value_class && !value_has_oops); 708 // if (!fieldinfo.field_flags().is_null_free_inline_type()) { 709 if (!is_candidate_for_flattening) { 710 if (group != _static_fields) _nonstatic_oopmap_count++; 711 group->add_oop_field(idx); 712 } else { 713 assert(type != T_ARRAY, "null free ptr to array not supported"); 714 _has_inline_type_fields = true; 715 if (group == _static_fields) { 716 // static fields are never flat 717 group->add_oop_field(idx); 718 } else { 719 // Check below is performed for non-static fields, it should be performed for static fields too but at this stage, 720 // it is not guaranteed that the klass of the static field has been loaded, so the test for static fields is delayed 721 // until the linking phase 722 Klass* klass = _inline_type_field_klasses->at(idx); 723 assert(klass != nullptr, "Sanity check"); 724 InlineKlass* vk = InlineKlass::cast(klass); 725 assert(!fieldinfo.field_flags().is_null_free_inline_type() || vk->is_implicitly_constructible(), "must be, should have been checked in post_process_parsed_stream()"); 726 _has_flattening_information = true; 727 // Flattening decision to be taken here 728 // This code assumes all verification already have been performed 729 // (field's type has been loaded and it is an inline klass) 730 bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 && 731 (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize); 732 bool too_atomic_to_flatten = vk->must_be_atomic() || AlwaysAtomicAccesses; 733 bool too_volatile_to_flatten = fieldinfo.access_flags().is_volatile(); 734 if (vk->is_naturally_atomic()) { 735 too_atomic_to_flatten = false; 736 //too_volatile_to_flatten = false; //FIXME 737 // Currently, volatile fields are never flat, this could change in the future 738 } 739 if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten)) { 740 group->add_flat_field(idx, vk, !fieldinfo.field_flags().is_null_free_inline_type()); 741 _nonstatic_oopmap_count += vk->nonstatic_oop_map_count(); 742 _field_info->adr_at(idx)->field_flags_addr()->update_flat(true); 743 if (!vk->is_atomic()) { // flat and non-atomic: take note 744 _has_nonatomic_values = true; 745 _atomic_field_count--; // every other field is atomic but this one 746 } 747 if (!fieldinfo.field_flags().is_null_free_inline_type()) _has_null_markers = true; 748 } else { 749 _nonstatic_oopmap_count++; 750 group->add_oop_field(idx); 751 } 752 } 753 } 754 break; 755 } 756 default: 757 fatal("Something wrong?"); 758 } 759 } 760 _root_group->sort_by_size(); 761 _static_fields->sort_by_size(); 762 if (!_contended_groups.is_empty()) { 763 for (int i = 0; i < _contended_groups.length(); i++) { 764 _contended_groups.at(i)->sort_by_size(); 765 } 766 } 767 } 768 769 /* Field sorting for inline classes: 770 * - because inline classes are immutable, the @Contended annotation is ignored 771 * when computing their layout (with only read operation, there's no false 772 * sharing issue) 773 * - this method also records the alignment of the field with the most 774 * constraining alignment, this value is then used as the alignment 775 * constraint when flattening this inline type into another container 776 * - field flattening decisions are taken in this method (those decisions are 777 * currently only based in the size of the fields to be flattened, the size 778 * of the resulting instance is not considered) 779 */ 780 void FieldLayoutBuilder::inline_class_field_sorting() { 781 assert(_is_inline_type || _is_abstract_value, "Should only be used for inline classes"); 782 int alignment = -1; 783 for (GrowableArrayIterator<FieldInfo> it = _field_info->begin(); it != _field_info->end(); ++it) { 784 FieldGroup* group = nullptr; 785 FieldInfo fieldinfo = *it; 786 int field_alignment = 1; 787 if (fieldinfo.access_flags().is_static()) { 788 group = _static_fields; 789 } else { 790 _has_nonstatic_fields = true; 791 _atomic_field_count++; // we might decrement this 792 group = _root_group; 793 } 794 assert(group != nullptr, "invariant"); 795 BasicType type = Signature::basic_type(fieldinfo.signature(_constant_pool)); 796 switch(type) { 797 case T_BYTE: 798 case T_CHAR: 799 case T_DOUBLE: 800 case T_FLOAT: 801 case T_INT: 802 case T_LONG: 803 case T_SHORT: 804 case T_BOOLEAN: 805 if (group != _static_fields) { 806 field_alignment = type2aelembytes(type); // alignment == size for primitive types 807 } 808 group->add_primitive_field(fieldinfo.index(), type); 809 break; 810 case T_OBJECT: 811 case T_ARRAY: 812 { 813 bool field_is_known_value_class = !fieldinfo.field_flags().is_injected() && _inline_type_field_klasses != nullptr && _inline_type_field_klasses->at(fieldinfo.index()) != nullptr; 814 bool value_has_oops = field_is_known_value_class ? _inline_type_field_klasses->at(fieldinfo.index())->nonstatic_oop_count() > 0 : true; 815 bool is_candidate_for_flattening = fieldinfo.field_flags().is_null_free_inline_type() || (EnableNullableFieldFlattening && field_is_known_value_class && !value_has_oops); 816 // if (!fieldinfo.field_flags().is_null_free_inline_type()) { 817 if (!is_candidate_for_flattening) { 818 if (group != _static_fields) { 819 _nonstatic_oopmap_count++; 820 field_alignment = type2aelembytes(type); // alignment == size for oops 821 } 822 group->add_oop_field(fieldinfo.index()); 823 } else { 824 assert(type != T_ARRAY, "null free ptr to array not supported"); 825 _has_inline_type_fields = true; 826 if (group == _static_fields) { 827 // static fields are never flat 828 group->add_oop_field(fieldinfo.index()); 829 } else { 830 // Check below is performed for non-static fields, it should be performed for static fields too but at this stage, 831 // it is not guaranteed that the klass of the static field has been loaded, so the test for static fields is delayed 832 // until the linking phase 833 Klass* klass = _inline_type_field_klasses->at(fieldinfo.index()); 834 assert(klass != nullptr, "Sanity check"); 835 InlineKlass* vk = InlineKlass::cast(klass); 836 assert(vk->is_implicitly_constructible(), "must be, should have been checked in post_process_parsed_stream()"); 837 // Flattening decision to be taken here 838 // This code assumes all verifications have already been performed 839 // (field's type has been loaded and it is an inline klass) 840 bool too_big_to_flatten = (InlineFieldMaxFlatSize >= 0 && 841 (vk->size_helper() * HeapWordSize) > InlineFieldMaxFlatSize); 842 bool too_atomic_to_flatten = vk->must_be_atomic() || AlwaysAtomicAccesses; 843 bool too_volatile_to_flatten = fieldinfo.access_flags().is_volatile(); 844 if (vk->is_naturally_atomic()) { 845 too_atomic_to_flatten = false; 846 //too_volatile_to_flatten = false; //FIXME 847 // Currently, volatile fields are never flat, this could change in the future 848 } 849 if (!(too_big_to_flatten | too_atomic_to_flatten | too_volatile_to_flatten)) { 850 group->add_flat_field(fieldinfo.index(), vk, !fieldinfo.field_flags().is_null_free_inline_type()); 851 _nonstatic_oopmap_count += vk->nonstatic_oop_map_count(); 852 field_alignment = vk->get_alignment(); 853 _field_info->adr_at(fieldinfo.index())->field_flags_addr()->update_flat(true); 854 if (!vk->is_atomic()) { // flat and non-atomic: take note 855 _has_nonatomic_values = true; 856 _atomic_field_count--; // every other field is atomic but this one 857 } 858 if (!fieldinfo.field_flags().is_null_free_inline_type()) _has_null_markers = true; 859 } else { 860 _nonstatic_oopmap_count++; 861 field_alignment = type2aelembytes(T_OBJECT); 862 group->add_oop_field(fieldinfo.index()); 863 } 864 } 865 } 866 break; 867 } 868 default: 869 fatal("Unexpected BasicType"); 870 } 871 if (!fieldinfo.access_flags().is_static() && field_alignment > alignment) alignment = field_alignment; 872 } 873 _alignment = alignment; 874 assert(_has_nonstatic_fields || _is_abstract_value, "Concrete value types do not support zero instance size yet"); 875 } 876 877 void FieldLayoutBuilder::insert_contended_padding(LayoutRawBlock* slot) { 878 if (ContendedPaddingWidth > 0) { 879 LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, ContendedPaddingWidth); 880 _layout->insert(slot, padding); 881 } 882 } 883 884 /* Computation of regular classes layout is an evolution of the previous default layout 885 * (FieldAllocationStyle 1): 886 * - primitive fields (both primitive types and flat inline types) are allocated 887 * first, from the biggest to the smallest 888 * - then oop fields are allocated (to increase chances to have contiguous oops and 889 * a simpler oopmap). 890 */ 891 void FieldLayoutBuilder::compute_regular_layout() { 892 bool need_tail_padding = false; 893 prologue(); 894 regular_field_sorting(); 895 if (_is_contended) { 896 _layout->set_start(_layout->last_block()); 897 // insertion is currently easy because the current strategy doesn't try to fill holes 898 // in super classes layouts => the _start block is by consequence the _last_block 899 insert_contended_padding(_layout->start()); 900 need_tail_padding = true; 901 } 902 _layout->add(_root_group->big_primitive_fields()); 903 _layout->add(_root_group->small_primitive_fields()); 904 _layout->add(_root_group->oop_fields()); 905 906 if (!_contended_groups.is_empty()) { 907 for (int i = 0; i < _contended_groups.length(); i++) { 908 FieldGroup* cg = _contended_groups.at(i); 909 LayoutRawBlock* start = _layout->last_block(); 910 insert_contended_padding(start); 911 _layout->add(cg->big_primitive_fields()); 912 _layout->add(cg->small_primitive_fields(), start); 913 _layout->add(cg->oop_fields(), start); 914 need_tail_padding = true; 915 } 916 } 917 918 if (need_tail_padding) { 919 insert_contended_padding(_layout->last_block()); 920 } 921 922 if (EnableNullableFieldFlattening && _layout->has_missing_null_markers()) { 923 insert_null_markers(); 924 } 925 926 // Warning: IntanceMirrorKlass expects static oops to be allocated first 927 _static_layout->add_contiguously(_static_fields->oop_fields()); 928 _static_layout->add(_static_fields->big_primitive_fields()); 929 _static_layout->add(_static_fields->small_primitive_fields()); 930 931 epilogue(); 932 } 933 934 void FieldLayoutBuilder::insert_null_markers() { 935 if (!EnableNullableFieldFlattening || !_layout->has_missing_null_markers()) return; 936 GrowableArray<LayoutRawBlock*>* list = new GrowableArray<LayoutRawBlock*>(10); 937 for (LayoutRawBlock* block = _layout->first_field_block(); block != _layout->last_block(); block = block->next_block()) { 938 if (block->needs_null_marker()) { 939 assert(block->kind() == LayoutRawBlock::FLAT, "Only flat fields might need null markers"); 940 if (block->inline_klass()->has_internal_null_marker_offset()) { 941 // The inline klass has an internal null marker slot, let's use it 942 // The inline klass has the internal null marker offset from the begining of the object, 943 // compute the offset relative to begining of payload 944 int internal_null_marker_offset = block->inline_klass()->get_internal_null_marker_offset() - block->inline_klass()->first_field_offset(); 945 block->set_null_marker_offset(block->offset() + internal_null_marker_offset); 946 _field_info->adr_at(block->field_index())->set_null_marker_offset(block->null_marker_offset()); 947 _field_info->adr_at(block->field_index())->field_flags_addr()->update_null_marker(true); 948 _field_info->adr_at(block->field_index())->field_flags_addr()->update_internal_null_marker(true); 949 } else { 950 // No internal null marker, need a external slot in the container 951 LayoutRawBlock* marker = new LayoutRawBlock(LayoutRawBlock::NULL_MARKER, 1); 952 marker->set_field_index(block->field_index()); 953 list->append(marker); 954 } 955 } 956 } 957 _layout->add(list); 958 for (GrowableArrayIterator<LayoutRawBlock*> it = list->begin(); it != list->end(); ++it) { 959 LayoutRawBlock* block = *it; 960 assert(block->offset() != -1, "Must be set"); 961 assert(!block->needs_null_marker(), "Must have been set"); 962 _field_info->adr_at(block->field_index())->set_null_marker_offset(block->offset()); 963 _field_info->adr_at(block->field_index())->field_flags_addr()->update_null_marker(true); 964 } 965 } 966 967 /* Computation of inline classes has a slightly different strategy than for 968 * regular classes. Regular classes have their oop fields allocated at the end 969 * of the layout to increase GC performances. Unfortunately, this strategy 970 * increases the number of empty slots inside an instance. Because the purpose 971 * of inline classes is to be embedded into other containers, it is critical 972 * to keep their size as small as possible. For this reason, the allocation 973 * strategy is: 974 * - big primitive fields (primitive types and flat inline type smaller 975 * than an oop) are allocated first (from the biggest to the smallest) 976 * - then oop fields 977 * - then small primitive fields (from the biggest to the smallest) 978 */ 979 void FieldLayoutBuilder::compute_inline_class_layout() { 980 prologue(); 981 inline_class_field_sorting(); 982 983 assert(_layout->start()->kind() == LayoutRawBlock::RESERVED, "Unexpected"); 984 985 if (_layout->super_has_fields() && !_is_abstract_value) { // non-static field layout 986 if (!_has_nonstatic_fields) { 987 assert(_is_abstract_value, "Concrete value types have at least one field"); 988 // Nothing to do 989 } else { 990 // decide which alignment to use, then set first allowed field offset 991 992 assert(_layout->super_alignment() >= _alignment, "Incompatible alignment"); 993 assert(_layout->super_alignment() % _alignment == 0, "Incompatible alignment"); 994 995 if (_alignment < _layout->super_alignment()) { 996 int new_alignment = _alignment > _layout->super_min_align_required() ? _alignment : _layout->super_min_align_required(); 997 assert(new_alignment % _alignment == 0, "Must be"); 998 assert(new_alignment % _layout->super_min_align_required() == 0, "Must be"); 999 _alignment = new_alignment; 1000 } 1001 if (_layout->first_empty_block()->offset() < _layout->first_field_block()->offset()) { 1002 LayoutRawBlock* first_empty = _layout->start()->next_block(); 1003 if (first_empty->offset() % _alignment != 0) { 1004 int size = _alignment - (first_empty->offset() % _alignment); 1005 LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, size); 1006 _layout->insert(first_empty, padding); 1007 _layout->set_start(padding); 1008 } else { 1009 _layout->set_start( _layout->start()); 1010 } 1011 } else { 1012 _layout->set_start(_layout->first_field_block()); 1013 } 1014 } 1015 } else { 1016 if (_is_abstract_value && _has_nonstatic_fields) { 1017 _alignment = type2aelembytes(BasicType::T_LONG); 1018 } 1019 assert(_layout->start()->next_block()->kind() == LayoutRawBlock::EMPTY || !UseCompressedClassPointers, "Unexpected"); 1020 LayoutRawBlock* first_empty = _layout->start()->next_block(); 1021 if (first_empty->offset() % _alignment != 0) { 1022 LayoutRawBlock* padding = new LayoutRawBlock(LayoutRawBlock::PADDING, _alignment - (first_empty->offset() % _alignment)); 1023 _layout->insert(first_empty, padding); 1024 if (first_empty->size() == 0) { 1025 _layout->remove(first_empty); 1026 } 1027 _layout->set_start(padding); 1028 } 1029 } 1030 1031 _layout->add(_root_group->big_primitive_fields()); 1032 _layout->add(_root_group->oop_fields()); 1033 _layout->add(_root_group->small_primitive_fields()); 1034 1035 if (EnableNullableFieldFlattening && _layout->has_missing_null_markers()) { 1036 insert_null_markers(); 1037 } 1038 1039 LayoutRawBlock* first_field = _layout->first_field_block(); 1040 if (first_field != nullptr) { 1041 _first_field_offset = _layout->first_field_block()->offset(); 1042 _payload_size_in_bytes = _layout->last_block()->offset() - _layout->first_field_block()->offset(); 1043 } else { 1044 // special case for empty value types 1045 _first_field_offset = _layout->blocks()->size(); 1046 _payload_size_in_bytes = 0; 1047 } 1048 if (_layout->first_field_block() == nullptr) { 1049 assert(_is_abstract_value, "Concrete inline types must have at least one field"); 1050 _payload_size_in_bytes = 0; 1051 } else { 1052 _payload_size_in_bytes = _layout->last_block()->offset() - _layout->first_field_block()->offset(); 1053 } 1054 1055 // Looking if there's an empty slot inside the layout that could be used to store a null marker 1056 LayoutRawBlock* b = _layout->first_field_block(); 1057 if (b != nullptr) { 1058 while (b != _layout->last_block()) { 1059 if (b->kind() == LayoutRawBlock::EMPTY) { 1060 break; 1061 } 1062 b = b->next_block(); 1063 } 1064 if (b != _layout->last_block()) { 1065 // found an empty slot, register its offset from the beginning of the payload 1066 _internal_null_marker_offset = b->offset(); 1067 } 1068 } else { 1069 assert(_is_abstract_value, "Only abstract value can have no fields"); 1070 } 1071 1072 // Warning:: InstanceMirrorKlass expects static oops to be allocated first 1073 _static_layout->add_contiguously(_static_fields->oop_fields()); 1074 _static_layout->add(_static_fields->big_primitive_fields()); 1075 _static_layout->add(_static_fields->small_primitive_fields()); 1076 1077 epilogue(); 1078 } 1079 1080 void FieldLayoutBuilder::add_flat_field_oopmap(OopMapBlocksBuilder* nonstatic_oop_maps, 1081 InlineKlass* vklass, int offset) { 1082 int diff = offset - vklass->first_field_offset(); 1083 const OopMapBlock* map = vklass->start_of_nonstatic_oop_maps(); 1084 const OopMapBlock* last_map = map + vklass->nonstatic_oop_map_count(); 1085 while (map < last_map) { 1086 nonstatic_oop_maps->add(map->offset() + diff, map->count()); 1087 map++; 1088 } 1089 } 1090 1091 void FieldLayoutBuilder::register_embedded_oops_from_list(OopMapBlocksBuilder* nonstatic_oop_maps, GrowableArray<LayoutRawBlock*>* list) { 1092 if (list != nullptr) { 1093 for (int i = 0; i < list->length(); i++) { 1094 LayoutRawBlock* f = list->at(i); 1095 if (f->kind() == LayoutRawBlock::FLAT) { 1096 InlineKlass* vk = f->inline_klass(); 1097 assert(vk != nullptr, "Should have been initialized"); 1098 if (vk->contains_oops()) { 1099 add_flat_field_oopmap(nonstatic_oop_maps, vk, f->offset()); 1100 } 1101 } 1102 } 1103 } 1104 } 1105 1106 void FieldLayoutBuilder::register_embedded_oops(OopMapBlocksBuilder* nonstatic_oop_maps, FieldGroup* group) { 1107 if (group->oop_fields() != nullptr) { 1108 for (int i = 0; i < group->oop_fields()->length(); i++) { 1109 LayoutRawBlock* b = group->oop_fields()->at(i); 1110 nonstatic_oop_maps->add(b->offset(), 1); 1111 } 1112 } 1113 register_embedded_oops_from_list(nonstatic_oop_maps, group->big_primitive_fields()); 1114 register_embedded_oops_from_list(nonstatic_oop_maps, group->small_primitive_fields()); 1115 } 1116 1117 void FieldLayoutBuilder::epilogue() { 1118 // Computing oopmaps 1119 int super_oop_map_count = (_super_klass == nullptr) ? 0 :_super_klass->nonstatic_oop_map_count(); 1120 int max_oop_map_count = super_oop_map_count + _nonstatic_oopmap_count; 1121 OopMapBlocksBuilder* nonstatic_oop_maps = 1122 new OopMapBlocksBuilder(max_oop_map_count); 1123 if (super_oop_map_count > 0) { 1124 nonstatic_oop_maps->initialize_inherited_blocks(_super_klass->start_of_nonstatic_oop_maps(), 1125 _super_klass->nonstatic_oop_map_count()); 1126 } 1127 register_embedded_oops(nonstatic_oop_maps, _root_group); 1128 if (!_contended_groups.is_empty()) { 1129 for (int i = 0; i < _contended_groups.length(); i++) { 1130 FieldGroup* cg = _contended_groups.at(i); 1131 if (cg->oop_count() > 0) { 1132 assert(cg->oop_fields() != nullptr && cg->oop_fields()->at(0) != nullptr, "oop_count > 0 but no oop fields found"); 1133 register_embedded_oops(nonstatic_oop_maps, cg); 1134 } 1135 } 1136 } 1137 nonstatic_oop_maps->compact(); 1138 1139 int instance_end = align_up(_layout->last_block()->offset(), wordSize); 1140 int static_fields_end = align_up(_static_layout->last_block()->offset(), wordSize); 1141 int static_fields_size = (static_fields_end - 1142 InstanceMirrorKlass::offset_of_static_fields()) / wordSize; 1143 int nonstatic_field_end = align_up(_layout->last_block()->offset(), heapOopSize); 1144 1145 // Pass back information needed for InstanceKlass creation 1146 1147 _info->oop_map_blocks = nonstatic_oop_maps; 1148 _info->_instance_size = align_object_size(instance_end / wordSize); 1149 _info->_static_field_size = static_fields_size; 1150 _info->_nonstatic_field_size = (nonstatic_field_end - instanceOopDesc::base_offset_in_bytes()) / heapOopSize; 1151 _info->_has_nonstatic_fields = _has_nonstatic_fields; 1152 _info->_has_inline_fields = _has_inline_type_fields; 1153 _info->_has_null_marker_offsets = _has_null_markers; 1154 1155 // An inline type is naturally atomic if it has just one field, and 1156 // that field is simple enough. 1157 _info->_is_naturally_atomic = (_is_inline_type && 1158 (_atomic_field_count <= 1) && 1159 !_has_nonatomic_values && 1160 _contended_groups.is_empty()); 1161 // This may be too restrictive, since if all the fields fit in 64 1162 // bits we could make the decision to align instances of this class 1163 // to 64-bit boundaries, and load and store them as single words. 1164 // And on machines which supported larger atomics we could similarly 1165 // allow larger values to be atomic, if properly aligned. 1166 1167 #ifdef ASSERT 1168 // Tests verifying integrity of field layouts are using the output of -XX:+PrintFieldLayout 1169 // which prints the details of LayoutRawBlocks used to compute the layout. 1170 // The code below checks that offsets in the _field_info meta-data match offsets 1171 // in the LayoutRawBlocks 1172 LayoutRawBlock* b = _layout->blocks(); 1173 while(b != _layout->last_block()) { 1174 if (b->kind() == LayoutRawBlock::REGULAR || b->kind() == LayoutRawBlock::FLAT) { 1175 assert(_field_info->adr_at(b->field_index())->offset() == (u4)b->offset()," Must match"); 1176 } 1177 b = b->next_block(); 1178 } 1179 b = _static_layout->blocks(); 1180 while(b != _static_layout->last_block()) { 1181 if (b->kind() == LayoutRawBlock::REGULAR || b->kind() == LayoutRawBlock::FLAT) { 1182 assert(_field_info->adr_at(b->field_index())->offset() == (u4)b->offset()," Must match"); 1183 } 1184 b = b->next_block(); 1185 } 1186 #endif // ASSERT 1187 1188 static bool first_layout_print = true; 1189 1190 1191 if (PrintFieldLayout || (PrintInlineLayout && _has_flattening_information)) { 1192 ResourceMark rm; 1193 stringStream st; 1194 if (first_layout_print) { 1195 st.print_cr("Field layout log format: @offset size/alignment [name] [signature] [comment]"); 1196 st.print_cr("Heap oop size = %d", heapOopSize); 1197 first_layout_print = false; 1198 } 1199 if (_super_klass != nullptr) { 1200 st.print_cr("Layout of class %s@%p extends %s@%p", _classname->as_C_string(), 1201 _loader_data, _super_klass->name()->as_C_string(), _super_klass->class_loader_data()); 1202 } else { 1203 st.print_cr("Layout of class %s@%p", _classname->as_C_string(), _loader_data); 1204 } 1205 st.print_cr("Instance fields:"); 1206 _layout->print(&st, false, _super_klass, _inline_type_field_klasses); 1207 st.print_cr("Static fields:"); 1208 _static_layout->print(&st, true, nullptr, _inline_type_field_klasses); 1209 st.print_cr("Instance size = %d bytes", _info->_instance_size * wordSize); 1210 if (_is_inline_type) { 1211 st.print_cr("First field offset = %d", _first_field_offset); 1212 st.print_cr("Alignment = %d bytes", _alignment); 1213 st.print_cr("Exact size = %d bytes", _payload_size_in_bytes); 1214 if (_internal_null_marker_offset != -1) { 1215 st.print_cr("Null marker offset = %d", _internal_null_marker_offset); 1216 } 1217 } 1218 st.print_cr("---"); 1219 // Print output all together. 1220 tty->print_raw(st.as_string()); 1221 } 1222 } 1223 1224 void FieldLayoutBuilder::build_layout() { 1225 if (_is_inline_type || _is_abstract_value) { 1226 compute_inline_class_layout(); 1227 } else { 1228 compute_regular_layout(); 1229 } 1230 }