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 }