-
Notifications
You must be signed in to change notification settings - Fork 1.7k
/
Copy pathprogram_visitor.cc
1589 lines (1372 loc) · 53 KB
/
program_visitor.cc
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
// Copyright (c) 2015, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/program_visitor.h"
#include "vm/canonical_tables.h"
#include "vm/closure_functions_cache.h"
#include "vm/code_patcher.h"
#include "vm/deopt_instructions.h"
#include "vm/hash_map.h"
#include "vm/object.h"
#include "vm/object_store.h"
#include "vm/symbols.h"
namespace dart {
class WorklistElement : public ZoneAllocated {
public:
WorklistElement(Zone* zone, const Object& object)
: object_(Object::Handle(zone, object.ptr())), next_(nullptr) {}
ObjectPtr value() const { return object_.ptr(); }
void set_next(WorklistElement* elem) { next_ = elem; }
WorklistElement* next() const { return next_; }
private:
const Object& object_;
WorklistElement* next_;
DISALLOW_COPY_AND_ASSIGN(WorklistElement);
};
// Implements a FIFO queue, using IsEmpty, Add, Remove operations.
class Worklist : public ValueObject {
public:
explicit Worklist(Zone* zone)
: zone_(zone), first_(nullptr), last_(nullptr) {}
bool IsEmpty() const { return first_ == nullptr; }
void Add(const Object& value) {
auto element = new (zone_) WorklistElement(zone_, value);
if (first_ == nullptr) {
first_ = element;
ASSERT(last_ == nullptr);
} else {
ASSERT(last_ != nullptr);
last_->set_next(element);
}
last_ = element;
ASSERT(first_ != nullptr && last_ != nullptr);
}
ObjectPtr Remove() {
ASSERT(first_ != nullptr);
WorklistElement* result = first_;
first_ = first_->next();
if (first_ == nullptr) {
last_ = nullptr;
}
return result->value();
}
private:
Zone* const zone_;
WorklistElement* first_;
WorklistElement* last_;
DISALLOW_COPY_AND_ASSIGN(Worklist);
};
// Walks through the classes, functions, and code for the current program.
//
// Uses the heap object ID table to determine whether or not a given object
// has been visited already.
class ProgramWalker : public ValueObject {
public:
ProgramWalker(Zone* zone, Heap* heap, ClassVisitor* visitor)
: heap_(heap),
visitor_(visitor),
worklist_(zone),
class_object_(Object::Handle(zone)),
class_fields_(Array::Handle(zone)),
class_field_(Field::Handle(zone)),
class_functions_(Array::Handle(zone)),
class_function_(Function::Handle(zone)),
class_code_(Code::Handle(zone)),
function_code_(Code::Handle(zone)),
static_calls_array_(Array::Handle(zone)),
static_calls_table_entry_(Object::Handle(zone)),
worklist_entry_(Object::Handle(zone)) {}
~ProgramWalker() { heap_->ResetObjectIdTable(); }
// Adds the given object to the worklist if it's an object type that the
// visitor can visit.
void AddToWorklist(const Object& object) {
// We don't visit null, non-heap objects, or objects in the VM heap.
if (object.IsNull() || object.IsSmi() || object.InVMIsolateHeap()) return;
// Check and set visited, even if we don't end up adding this to the list.
if (heap_->GetObjectId(object.ptr()) != 0) return;
heap_->SetObjectId(object.ptr(), 1);
if (object.IsClass() ||
(object.IsFunction() && visitor_->IsFunctionVisitor()) ||
(object.IsCode() && visitor_->IsCodeVisitor())) {
worklist_.Add(object);
}
}
void VisitWorklist() {
while (!worklist_.IsEmpty()) {
worklist_entry_ = worklist_.Remove();
if (worklist_entry_.IsClass()) {
VisitClass(Class::Cast(worklist_entry_));
} else if (worklist_entry_.IsFunction()) {
VisitFunction(Function::Cast(worklist_entry_));
} else if (worklist_entry_.IsCode()) {
VisitCode(Code::Cast(worklist_entry_));
} else {
FATAL("Got unexpected object %s", worklist_entry_.ToCString());
}
}
}
private:
void VisitClass(const Class& cls) {
visitor_->VisitClass(cls);
if (!visitor_->IsFunctionVisitor()) return;
class_functions_ = cls.current_functions();
for (intptr_t j = 0; j < class_functions_.Length(); j++) {
class_function_ ^= class_functions_.At(j);
AddToWorklist(class_function_);
if (class_function_.HasImplicitClosureFunction()) {
class_function_ = class_function_.ImplicitClosureFunction();
AddToWorklist(class_function_);
}
}
class_functions_ = cls.invocation_dispatcher_cache();
for (intptr_t j = 0; j < class_functions_.Length(); j++) {
class_object_ = class_functions_.At(j);
if (class_object_.IsFunction()) {
class_function_ ^= class_functions_.At(j);
AddToWorklist(class_function_);
}
}
class_fields_ = cls.fields();
for (intptr_t j = 0; j < class_fields_.Length(); j++) {
class_field_ ^= class_fields_.At(j);
if (class_field_.HasInitializerFunction()) {
class_function_ = class_field_.InitializerFunction();
AddToWorklist(class_function_);
}
}
if (!visitor_->IsCodeVisitor()) return;
class_code_ = cls.allocation_stub();
if (!class_code_.IsNull()) AddToWorklist(class_code_);
}
void VisitFunction(const Function& function) {
ASSERT(visitor_->IsFunctionVisitor());
visitor_->AsFunctionVisitor()->VisitFunction(function);
if (!visitor_->IsCodeVisitor() || !function.HasCode()) return;
function_code_ = function.CurrentCode();
AddToWorklist(function_code_);
}
void VisitCode(const Code& code) {
ASSERT(visitor_->IsCodeVisitor());
visitor_->AsCodeVisitor()->VisitCode(code);
// In the precompiler, some entries in the static calls table may need
// to be visited as they may not be reachable from other sources.
//
// TODO(dartbug.com/41636): Figure out why walking the static calls table
// in JIT mode with the DedupInstructions visitor fails, so we can remove
// the check for AOT mode.
static_calls_array_ = code.static_calls_target_table();
if (FLAG_precompiled_mode && !static_calls_array_.IsNull()) {
StaticCallsTable static_calls(static_calls_array_);
for (auto& view : static_calls) {
static_calls_table_entry_ =
view.Get<Code::kSCallTableCodeOrTypeTarget>();
if (static_calls_table_entry_.IsCode()) {
AddToWorklist(Code::Cast(static_calls_table_entry_));
}
}
}
}
Heap* const heap_;
ClassVisitor* const visitor_;
Worklist worklist_;
Object& class_object_;
Array& class_fields_;
Field& class_field_;
Array& class_functions_;
Function& class_function_;
Code& class_code_;
Code& function_code_;
Array& static_calls_array_;
Object& static_calls_table_entry_;
Object& worklist_entry_;
};
void ProgramVisitor::WalkProgram(Zone* zone,
IsolateGroup* isolate_group,
ClassVisitor* visitor) {
auto const object_store = isolate_group->object_store();
auto const heap = isolate_group->heap();
ProgramWalker walker(zone, heap, visitor);
// Walk through the libraries looking for visitable objects.
const auto& libraries =
GrowableObjectArray::Handle(zone, object_store->libraries());
auto& lib = Library::Handle(zone);
auto& cls = Class::Handle(zone);
for (intptr_t i = 0; i < libraries.Length(); i++) {
lib ^= libraries.At(i);
ClassDictionaryIterator it(lib, ClassDictionaryIterator::kIteratePrivate);
while (it.HasNext()) {
cls = it.GetNextClass();
walker.AddToWorklist(cls);
}
}
// If there's a global object pool, add any visitable objects.
const auto& global_object_pool =
ObjectPool::Handle(zone, object_store->global_object_pool());
if (!global_object_pool.IsNull()) {
auto& object = Object::Handle(zone);
for (intptr_t i = 0; i < global_object_pool.Length(); i++) {
auto const type = global_object_pool.TypeAt(i);
if (type != ObjectPool::EntryType::kTaggedObject) continue;
object = global_object_pool.ObjectAt(i);
walker.AddToWorklist(object);
}
}
if (visitor->IsFunctionVisitor()) {
// Function objects not necessarily reachable from classes.
ClosureFunctionsCache::ForAllClosureFunctions([&](const Function& fun) {
walker.AddToWorklist(fun);
ASSERT(!fun.HasImplicitClosureFunction());
return true; // Continue iteration.
});
// TODO(dartbug.com/43049): Use a more general solution and remove manual
// tracking through object_store->ffi_callback_functions.
if (object_store->ffi_callback_functions() != Array::null()) {
auto& function = Function::Handle(zone);
FfiCallbackFunctionSet set(object_store->ffi_callback_functions());
FfiCallbackFunctionSet::Iterator it(&set);
while (it.MoveNext()) {
const intptr_t entry = it.Current();
function ^= set.GetKey(entry);
walker.AddToWorklist(function);
}
set.Release();
}
}
if (visitor->IsCodeVisitor()) {
// Code objects not necessarily reachable from functions.
auto& code = Code::Handle(zone);
const auto& dispatch_table_entries =
Array::Handle(zone, object_store->dispatch_table_code_entries());
if (!dispatch_table_entries.IsNull()) {
for (intptr_t i = 0; i < dispatch_table_entries.Length(); i++) {
code ^= dispatch_table_entries.At(i);
walker.AddToWorklist(code);
}
}
}
// Walk the program starting from any roots we added to the worklist.
walker.VisitWorklist();
}
// A base class for deduplication of objects. T is the type of canonical objects
// being stored, whereas S is a trait appropriate for a DirectChainedHashMap
// based set containing those canonical objects.
template <typename T, typename S>
class Deduper : public ValueObject {
public:
explicit Deduper(Zone* zone) : zone_(zone), canonical_objects_(zone) {}
virtual ~Deduper() {}
protected:
// Predicate for objects of type T. Must be overridden for class hierarchies
// like Instance and AbstractType, as it defaults to class ID comparison.
virtual bool IsCorrectType(const Object& obj) const {
return obj.GetClassId() == T::kClassId;
}
// Predicate for choosing Ts to canonicalize.
virtual bool CanCanonicalize(const T& t) const { return true; }
// Predicate for objects that are okay to add to the canonical hash set.
// Override IsCorrectType and/or CanCanonicalize to change the behavior.
bool ShouldAdd(const Object& obj) const {
return !obj.IsNull() && IsCorrectType(obj) && CanCanonicalize(T::Cast(obj));
}
void AddCanonical(const T& obj) {
if (!ShouldAdd(obj)) return;
ASSERT(!canonical_objects_.HasKey(&obj));
canonical_objects_.Insert(&T::ZoneHandle(zone_, obj.ptr()));
}
void AddVMBaseObjects() {
const auto& object_table = Object::vm_isolate_snapshot_object_table();
auto& obj = Object::Handle(zone_);
for (intptr_t i = 0; i < object_table.Length(); i++) {
obj = object_table.At(i);
if (!ShouldAdd(obj)) continue;
AddCanonical(T::Cast(obj));
}
}
typename T::ObjectPtrType Dedup(const T& obj) {
if (ShouldAdd(obj)) {
if (auto const canonical = canonical_objects_.LookupValue(&obj)) {
return canonical->ptr();
}
AddCanonical(obj);
}
return obj.ptr();
}
Zone* const zone_;
DirectChainedHashMap<S> canonical_objects_;
};
void ProgramVisitor::BindStaticCalls(Thread* thread) {
class BindStaticCallsVisitor : public CodeVisitor {
public:
explicit BindStaticCallsVisitor(Zone* zone)
: table_(Array::Handle(zone)),
kind_and_offset_(Smi::Handle(zone)),
target_(Object::Handle(zone)),
target_code_(Code::Handle(zone)) {}
void VisitCode(const Code& code) {
table_ = code.static_calls_target_table();
if (table_.IsNull()) return;
StaticCallsTable static_calls(table_);
// We can only remove the target table in precompiled mode, since more
// calls may be added later otherwise.
bool only_call_via_code = FLAG_precompiled_mode;
for (const auto& view : static_calls) {
kind_and_offset_ = view.Get<Code::kSCallTableKindAndOffset>();
auto const kind = Code::KindField::decode(kind_and_offset_.Value());
if (kind != Code::kCallViaCode) {
ASSERT(kind == Code::kPcRelativeCall ||
kind == Code::kPcRelativeTailCall ||
kind == Code::kPcRelativeTTSCall);
only_call_via_code = false;
continue;
}
target_ = view.Get<Code::kSCallTableFunctionTarget>();
if (target_.IsNull()) {
target_ =
Code::RawCast(view.Get<Code::kSCallTableCodeOrTypeTarget>());
ASSERT(!target_.IsNull()); // Already bound.
continue;
}
auto const pc_offset =
Code::OffsetField::decode(kind_and_offset_.Value());
const uword pc = pc_offset + code.PayloadStart();
// In JIT mode, static calls initially call the CallStaticFunction stub
// because their target might not be compiled yet. If the target has
// been compiled by this point, we patch the call to call the target
// directly.
//
// In precompiled mode, the binder runs after tree shaking, during which
// all targets have been compiled, and so the binder replaces all static
// calls with direct calls to the target.
//
// Cf. runtime entry PatchStaticCall called from CallStaticFunction
// stub.
const auto& fun = Function::Cast(target_);
ASSERT(!FLAG_precompiled_mode || fun.HasCode());
target_code_ = fun.HasCode() ? fun.CurrentCode()
: StubCode::CallStaticFunction().ptr();
CodePatcher::PatchStaticCallAt(pc, code, target_code_);
}
if (only_call_via_code) {
ASSERT(FLAG_precompiled_mode);
// In precompiled mode, the Dart runtime won't patch static calls
// anymore, so drop the static call table to save space.
// Note: it is okay to drop the table fully even when generating
// V8 snapshot profile because code objects are linked through the
// pool.
code.set_static_calls_target_table(Object::empty_array());
}
}
private:
Array& table_;
Smi& kind_and_offset_;
Object& target_;
Code& target_code_;
};
StackZone stack_zone(thread);
BindStaticCallsVisitor visitor(thread->zone());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
DECLARE_FLAG(charp, trace_precompiler_to);
DECLARE_FLAG(charp, write_v8_snapshot_profile_to);
void ProgramVisitor::ShareMegamorphicBuckets(Thread* thread) {
StackZone stack_zone(thread);
Zone* zone = thread->zone();
const GrowableObjectArray& table = GrowableObjectArray::Handle(
zone, thread->isolate_group()->object_store()->megamorphic_cache_table());
if (table.IsNull()) return;
MegamorphicCache& cache = MegamorphicCache::Handle(zone);
const intptr_t capacity = 1;
const Array& buckets = Array::Handle(
zone, Array::New(MegamorphicCache::kEntryLength * capacity, Heap::kOld));
const Function& handler = Function::Handle(zone);
MegamorphicCache::SetEntry(buckets, 0, Object::smi_illegal_cid(), handler);
for (intptr_t i = 0; i < table.Length(); i++) {
cache ^= table.At(i);
cache.set_buckets(buckets);
cache.set_mask(capacity - 1);
cache.set_filled_entry_count(0);
}
}
class StackMapEntry : public ZoneAllocated {
public:
StackMapEntry(Zone* zone,
const CompressedStackMaps::Iterator<CompressedStackMaps>& it)
: maps_(CompressedStackMaps::Handle(zone, it.maps_.ptr())),
bits_container_(
CompressedStackMaps::Handle(zone, it.bits_container_.ptr())),
// If the map uses the global table, this accessor call ensures the
// entry is fully loaded before we retrieve [it.current_bits_offset_].
spill_slot_bit_count_(it.SpillSlotBitCount()),
non_spill_slot_bit_count_(it.Length() - it.SpillSlotBitCount()),
bits_offset_(it.current_bits_offset_) {
ASSERT(!maps_.IsNull() && !maps_.IsGlobalTable());
ASSERT(!bits_container_.IsNull());
ASSERT(!maps_.UsesGlobalTable() || bits_container_.IsGlobalTable());
ASSERT(it.current_spill_slot_bit_count_ >= 0);
}
static constexpr intptr_t kHashBits = Object::kHashBits;
uword Hash() {
if (hash_ != 0) return hash_;
uint32_t hash = 0;
hash = CombineHashes(hash, spill_slot_bit_count_);
hash = CombineHashes(hash, non_spill_slot_bit_count_);
{
NoSafepointScope scope;
auto const start = PayloadData();
auto const end = start + PayloadLength();
for (auto cursor = start; cursor < end; cursor++) {
hash = CombineHashes(hash, *cursor);
}
}
hash_ = FinalizeHash(hash, kHashBits);
return hash_;
}
bool Equals(const StackMapEntry& other) const {
if (spill_slot_bit_count_ != other.spill_slot_bit_count_ ||
non_spill_slot_bit_count_ != other.non_spill_slot_bit_count_) {
return false;
}
// Since we ensure that bits in the payload that are not part of the
// actual stackmap data are cleared, we can just compare payloads by byte
// instead of calling IsObject for each bit.
NoSafepointScope scope;
return memcmp(PayloadData(), other.PayloadData(), PayloadLength()) == 0;
}
// Encodes this StackMapEntry to the given array of bytes and returns the
// initial offset of the entry in the array.
intptr_t EncodeTo(NonStreamingWriteStream* stream) {
auto const current_offset = stream->Position();
stream->WriteLEB128(spill_slot_bit_count_);
stream->WriteLEB128(non_spill_slot_bit_count_);
{
NoSafepointScope scope;
stream->WriteBytes(PayloadData(), PayloadLength());
}
return current_offset;
}
intptr_t UsageCount() const { return uses_; }
void IncrementUsageCount() { uses_ += 1; }
private:
intptr_t Length() const {
return spill_slot_bit_count_ + non_spill_slot_bit_count_;
}
intptr_t PayloadLength() const {
return Utils::RoundUp(Length(), kBitsPerByte) >> kBitsPerByteLog2;
}
const uint8_t* PayloadData() const {
return bits_container_.ptr()->untag()->payload()->data() + bits_offset_;
}
const CompressedStackMaps& maps_;
const CompressedStackMaps& bits_container_;
const intptr_t spill_slot_bit_count_;
const intptr_t non_spill_slot_bit_count_;
const intptr_t bits_offset_;
intptr_t uses_ = 1;
intptr_t hash_ = 0;
};
// Used for maps of indices and offsets. These are non-negative, and so the
// value for entries may be 0. Since 0 is kNoValue for
// RawPointerKeyValueTrait<const StackMapEntry, intptr_t>, we can't just use it.
class StackMapEntryKeyIntValueTrait {
public:
typedef StackMapEntry* Key;
typedef intptr_t Value;
struct Pair {
Key key;
Value value;
Pair() : key(nullptr), value(-1) {}
Pair(const Key key, const Value& value)
: key(ASSERT_NOTNULL(key)), value(value) {}
Pair(const Pair& other) : key(other.key), value(other.value) {}
Pair& operator=(const Pair&) = default;
};
static Key KeyOf(Pair kv) { return kv.key; }
static Value ValueOf(Pair kv) { return kv.value; }
static uword Hash(Key key) { return key->Hash(); }
static bool IsKeyEqual(Pair kv, Key key) { return key->Equals(*kv.key); }
};
typedef DirectChainedHashMap<StackMapEntryKeyIntValueTrait> StackMapEntryIntMap;
void ProgramVisitor::NormalizeAndDedupCompressedStackMaps(Thread* thread) {
// Walks all the CSMs in Code objects and collects their entry information
// for consolidation.
class CollectStackMapEntriesVisitor : public CodeVisitor {
public:
CollectStackMapEntriesVisitor(Zone* zone,
const CompressedStackMaps& global_table)
: zone_(zone),
old_global_table_(global_table),
compressed_stackmaps_(CompressedStackMaps::Handle(zone)),
collected_entries_(zone, 2),
entry_indices_(zone),
entry_offset_(zone) {
ASSERT(old_global_table_.IsNull() || old_global_table_.IsGlobalTable());
}
void VisitCode(const Code& code) {
compressed_stackmaps_ = code.compressed_stackmaps();
CompressedStackMaps::Iterator<CompressedStackMaps> it(
compressed_stackmaps_, old_global_table_);
while (it.MoveNext()) {
auto const entry = new (zone_) StackMapEntry(zone_, it);
auto const index = entry_indices_.LookupValue(entry);
if (index < 0) {
auto new_index = collected_entries_.length();
collected_entries_.Add(entry);
entry_indices_.Insert({entry, new_index});
} else {
collected_entries_.At(index)->IncrementUsageCount();
}
}
}
// Creates a new global table of stack map information. Also adds the
// offsets of encoded StackMapEntry objects to entry_offsets for use
// when normalizing CompressedStackMaps.
CompressedStackMapsPtr CreateGlobalTable(
StackMapEntryIntMap* entry_offsets) {
ASSERT(entry_offsets->IsEmpty());
if (collected_entries_.length() == 0) {
return CompressedStackMaps::null();
}
// First, sort the entries from most used to least used. This way,
// the most often used CSMs will have the lowest offsets, which means
// they will be smaller when LEB128 encoded.
collected_entries_.Sort(
[](StackMapEntry* const* e1, StackMapEntry* const* e2) {
return static_cast<int>((*e2)->UsageCount() - (*e1)->UsageCount());
});
MallocWriteStream stream(128);
// Encode the entries and record their offset in the payload. Sorting the
// entries may have changed their indices, so update those as well.
for (intptr_t i = 0, n = collected_entries_.length(); i < n; i++) {
auto const entry = collected_entries_.At(i);
entry_indices_.Update({entry, i});
entry_offsets->Insert({entry, entry->EncodeTo(&stream)});
}
const auto& data = CompressedStackMaps::Handle(
zone_, CompressedStackMaps::NewGlobalTable(stream.buffer(),
stream.bytes_written()));
return data.ptr();
}
private:
Zone* const zone_;
const CompressedStackMaps& old_global_table_;
CompressedStackMaps& compressed_stackmaps_;
GrowableArray<StackMapEntry*> collected_entries_;
StackMapEntryIntMap entry_indices_;
StackMapEntryIntMap entry_offset_;
};
// Walks all the CSMs in Code objects, normalizes them, and then dedups them.
//
// We use normalized to refer to CSMs whose entries are references to the
// new global table created during stack map collection, and non-normalized
// for CSMs that either have inlined entry information or whose entries are
// references to the _old_ global table in the object store, if any.
class NormalizeAndDedupCompressedStackMapsVisitor
: public CodeVisitor,
public Deduper<CompressedStackMaps,
PointerSetKeyValueTrait<const CompressedStackMaps>> {
public:
NormalizeAndDedupCompressedStackMapsVisitor(Zone* zone,
IsolateGroup* isolate_group)
: Deduper(zone),
old_global_table_(CompressedStackMaps::Handle(
zone,
isolate_group->object_store()
->canonicalized_stack_map_entries())),
entry_offsets_(zone),
maps_(CompressedStackMaps::Handle(zone)) {
ASSERT(old_global_table_.IsNull() || old_global_table_.IsGlobalTable());
// The stack map normalization and deduplication happens in two phases:
//
// 1) Visit all CompressedStackMaps (CSM) objects and collect individual
// entry info as canonicalized StackMapEntries (SMEs). Also record the
// frequency the same entry info was seen across all CSMs in each SME.
CollectStackMapEntriesVisitor collect_visitor(zone, old_global_table_);
WalkProgram(zone, isolate_group, &collect_visitor);
// The results of phase 1 are used to create a new global table with
// entries sorted by decreasing frequency, so that entries that appear
// more often in CSMs have smaller payload offsets (less bytes used in
// the LEB128 encoding). The new global table is put into place
// immediately, as we already have a handle on the old table.
const auto& new_global_table = CompressedStackMaps::Handle(
zone, collect_visitor.CreateGlobalTable(&entry_offsets_));
isolate_group->object_store()->set_canonicalized_stack_map_entries(
new_global_table);
// 2) Visit all CSMs and replace each with a canonicalized normalized
// version that uses the new global table for non-PC offset entry
// information. This part is done in VisitCode.
}
void VisitCode(const Code& code) {
maps_ = code.compressed_stackmaps();
if (maps_.IsNull()) return;
// First check is to make sure [maps] hasn't already been normalized,
// since any normalized map already has a canonical entry in the set.
if (auto const canonical = canonical_objects_.LookupValue(&maps_)) {
maps_ = canonical->ptr();
} else {
maps_ = NormalizeEntries(maps_);
maps_ = Dedup(maps_);
}
code.set_compressed_stackmaps(maps_);
}
private:
// Creates a normalized CSM from the given non-normalized CSM.
CompressedStackMapsPtr NormalizeEntries(const CompressedStackMaps& maps) {
if (maps.payload_size() == 0) {
// No entries, so use the canonical empty map.
return Object::empty_compressed_stackmaps().ptr();
}
MallocWriteStream new_payload(maps.payload_size());
CompressedStackMaps::Iterator<CompressedStackMaps> it(maps,
old_global_table_);
intptr_t last_offset = 0;
while (it.MoveNext()) {
StackMapEntry entry(zone_, it);
const intptr_t entry_offset = entry_offsets_.LookupValue(&entry);
const intptr_t pc_delta = it.pc_offset() - last_offset;
new_payload.WriteLEB128(pc_delta);
new_payload.WriteLEB128(entry_offset);
last_offset = it.pc_offset();
}
return CompressedStackMaps::NewUsingTable(new_payload.buffer(),
new_payload.bytes_written());
}
const CompressedStackMaps& old_global_table_;
StackMapEntryIntMap entry_offsets_;
CompressedStackMaps& maps_;
};
StackZone stack_zone(thread);
NormalizeAndDedupCompressedStackMapsVisitor visitor(thread->zone(),
thread->isolate_group());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
class PcDescriptorsKeyValueTrait {
public:
// Typedefs needed for the DirectChainedHashMap template.
typedef const PcDescriptors* Key;
typedef const PcDescriptors* Value;
typedef const PcDescriptors* Pair;
static Key KeyOf(Pair kv) { return kv; }
static Value ValueOf(Pair kv) { return kv; }
static inline uword Hash(Key key) { return Utils::WordHash(key->Length()); }
static inline bool IsKeyEqual(Pair pair, Key key) {
return pair->Equals(*key);
}
};
void ProgramVisitor::DedupPcDescriptors(Thread* thread) {
class DedupPcDescriptorsVisitor
: public CodeVisitor,
public Deduper<PcDescriptors, PcDescriptorsKeyValueTrait> {
public:
explicit DedupPcDescriptorsVisitor(Zone* zone)
: Deduper(zone), pc_descriptor_(PcDescriptors::Handle(zone)) {
if (Snapshot::IncludesCode(Dart::vm_snapshot_kind())) {
// Prefer existing objects in the VM isolate.
AddVMBaseObjects();
}
}
void VisitCode(const Code& code) {
pc_descriptor_ = code.pc_descriptors();
pc_descriptor_ = Dedup(pc_descriptor_);
code.set_pc_descriptors(pc_descriptor_);
}
private:
PcDescriptors& pc_descriptor_;
};
StackZone stack_zone(thread);
DedupPcDescriptorsVisitor visitor(thread->zone());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
class TypedDataKeyValueTrait {
public:
// Typedefs needed for the DirectChainedHashMap template.
typedef const TypedData* Key;
typedef const TypedData* Value;
typedef const TypedData* Pair;
static Key KeyOf(Pair kv) { return kv; }
static Value ValueOf(Pair kv) { return kv; }
static inline uword Hash(Key key) { return key->CanonicalizeHash(); }
static inline bool IsKeyEqual(Pair pair, Key key) {
return pair->CanonicalizeEquals(*key);
}
};
class TypedDataDeduper : public Deduper<TypedData, TypedDataKeyValueTrait> {
public:
explicit TypedDataDeduper(Zone* zone) : Deduper(zone) {}
private:
bool IsCorrectType(const Object& obj) const { return obj.IsTypedData(); }
};
void ProgramVisitor::DedupDeoptEntries(Thread* thread) {
class DedupDeoptEntriesVisitor : public CodeVisitor, public TypedDataDeduper {
public:
explicit DedupDeoptEntriesVisitor(Zone* zone)
: TypedDataDeduper(zone),
deopt_table_(Array::Handle(zone)),
deopt_entry_(TypedData::Handle(zone)),
offset_(Smi::Handle(zone)),
reason_and_flags_(Smi::Handle(zone)) {}
void VisitCode(const Code& code) {
deopt_table_ = code.deopt_info_array();
if (deopt_table_.IsNull()) return;
intptr_t length = DeoptTable::GetLength(deopt_table_);
for (intptr_t i = 0; i < length; i++) {
DeoptTable::GetEntry(deopt_table_, i, &offset_, &deopt_entry_,
&reason_and_flags_);
ASSERT(!deopt_entry_.IsNull());
deopt_entry_ = Dedup(deopt_entry_);
ASSERT(!deopt_entry_.IsNull());
DeoptTable::SetEntry(deopt_table_, i, offset_, deopt_entry_,
reason_and_flags_);
}
}
private:
Array& deopt_table_;
TypedData& deopt_entry_;
Smi& offset_;
Smi& reason_and_flags_;
};
if (FLAG_precompiled_mode) return;
StackZone stack_zone(thread);
DedupDeoptEntriesVisitor visitor(thread->zone());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
#if defined(DART_PRECOMPILER)
void ProgramVisitor::DedupCatchEntryMovesMaps(Thread* thread) {
class DedupCatchEntryMovesMapsVisitor : public CodeVisitor,
public TypedDataDeduper {
public:
explicit DedupCatchEntryMovesMapsVisitor(Zone* zone)
: TypedDataDeduper(zone),
catch_entry_moves_maps_(TypedData::Handle(zone)) {}
void VisitCode(const Code& code) {
catch_entry_moves_maps_ = code.catch_entry_moves_maps();
catch_entry_moves_maps_ = Dedup(catch_entry_moves_maps_);
code.set_catch_entry_moves_maps(catch_entry_moves_maps_);
}
private:
TypedData& catch_entry_moves_maps_;
};
if (!FLAG_precompiled_mode) return;
StackZone stack_zone(thread);
DedupCatchEntryMovesMapsVisitor visitor(thread->zone());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
class UnlinkedCallKeyValueTrait {
public:
// Typedefs needed for the DirectChainedHashMap template.
typedef const UnlinkedCall* Key;
typedef const UnlinkedCall* Value;
typedef const UnlinkedCall* Pair;
static Key KeyOf(Pair kv) { return kv; }
static Value ValueOf(Pair kv) { return kv; }
static inline uword Hash(Key key) { return key->Hash(); }
static inline bool IsKeyEqual(Pair pair, Key key) {
return pair->Equals(*key);
}
};
void ProgramVisitor::DedupUnlinkedCalls(Thread* thread) {
class DedupUnlinkedCallsVisitor
: public CodeVisitor,
public Deduper<UnlinkedCall, UnlinkedCallKeyValueTrait> {
public:
explicit DedupUnlinkedCallsVisitor(Zone* zone, IsolateGroup* isolate_group)
: Deduper(zone),
entry_(Object::Handle(zone)),
pool_(ObjectPool::Handle(zone)) {
auto& gop = ObjectPool::Handle(
zone, isolate_group->object_store()->global_object_pool());
ASSERT(!gop.IsNull());
DedupPool(gop);
}
void DedupPool(const ObjectPool& pool) {
if (pool.IsNull()) return;
for (intptr_t i = 0; i < pool.Length(); i++) {
if (pool.TypeAt(i) != ObjectPool::EntryType::kTaggedObject) {
continue;
}
entry_ = pool.ObjectAt(i);
if (!entry_.IsUnlinkedCall()) continue;
entry_ = Dedup(UnlinkedCall::Cast(entry_));
pool.SetObjectAt(i, entry_);
}
}
void VisitCode(const Code& code) {
pool_ = code.object_pool();
DedupPool(pool_);
}
private:
Object& entry_;
ObjectPool& pool_;
};
if (!FLAG_precompiled_mode) return;
StackZone stack_zone(thread);
DedupUnlinkedCallsVisitor visitor(thread->zone(), thread->isolate_group());
// Deduplicate local object pools as they are used to trace
// objects when writing snapshots.
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
void ProgramVisitor::PruneSubclasses(Thread* thread) {
class PruneSubclassesVisitor : public ClassVisitor {
public:
explicit PruneSubclassesVisitor(Zone* zone)
: ClassVisitor(),
old_implementors_(GrowableObjectArray::Handle(zone)),
new_implementors_(GrowableObjectArray::Handle(zone)),
implementor_(Class::Handle(zone)),
old_subclasses_(GrowableObjectArray::Handle(zone)),
new_subclasses_(GrowableObjectArray::Handle(zone)),
subclass_(Class::Handle(zone)),
null_list_(GrowableObjectArray::Handle(zone)) {}
void VisitClass(const Class& klass) {
old_implementors_ = klass.direct_implementors_unsafe();
if (!old_implementors_.IsNull()) {
new_implementors_ = GrowableObjectArray::New();
for (intptr_t i = 0; i < old_implementors_.Length(); i++) {
implementor_ ^= old_implementors_.At(i);
if (implementor_.id() != kIllegalCid) {
new_implementors_.Add(implementor_);
}
}
if (new_implementors_.Length() == 0) {
klass.set_direct_implementors(null_list_);
} else {
klass.set_direct_implementors(new_implementors_);
}
}
old_subclasses_ = klass.direct_subclasses_unsafe();
if (!old_subclasses_.IsNull()) {
new_subclasses_ = GrowableObjectArray::New();
for (intptr_t i = 0; i < old_subclasses_.Length(); i++) {
subclass_ ^= old_subclasses_.At(i);
if (subclass_.id() != kIllegalCid) {
new_subclasses_.Add(subclass_);
}
}
if (new_subclasses_.Length() == 0) {
klass.set_direct_subclasses(null_list_);
} else {
klass.set_direct_subclasses(new_subclasses_);
}
}
}
private:
GrowableObjectArray& old_implementors_;
GrowableObjectArray& new_implementors_;
Class& implementor_;
GrowableObjectArray& old_subclasses_;
GrowableObjectArray& new_subclasses_;
Class& subclass_;
GrowableObjectArray& null_list_;
};
StackZone stack_zone(thread);
PruneSubclassesVisitor visitor(thread->zone());
SafepointWriteRwLocker ml(thread, thread->isolate_group()->program_lock());
WalkProgram(thread->zone(), thread->isolate_group(), &visitor);
}
#endif // defined(DART_PRECOMPILER)
class CodeSourceMapKeyValueTrait {
public:
// Typedefs needed for the DirectChainedHashMap template.
typedef const CodeSourceMap* Key;