1 // Copyright 2018 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "src/snapshot/roots-serializer.h"
6
7 #include "src/execution/isolate.h"
8 #include "src/heap/heap.h"
9 #include "src/objects/objects-inl.h"
10 #include "src/objects/slots.h"
11
12 namespace v8 {
13 namespace internal {
14
RootsSerializer(Isolate * isolate,Snapshot::SerializerFlags flags,RootIndex first_root_to_be_serialized)15 RootsSerializer::RootsSerializer(Isolate* isolate,
16 Snapshot::SerializerFlags flags,
17 RootIndex first_root_to_be_serialized)
18 : Serializer(isolate, flags),
19 first_root_to_be_serialized_(first_root_to_be_serialized),
20 object_cache_index_map_(isolate->heap()),
21 can_be_rehashed_(true) {
22 for (size_t i = 0; i < static_cast<size_t>(first_root_to_be_serialized);
23 ++i) {
24 root_has_been_serialized_[i] = true;
25 }
26 }
27
SerializeInObjectCache(Handle<HeapObject> heap_object)28 int RootsSerializer::SerializeInObjectCache(Handle<HeapObject> heap_object) {
29 int index;
30 if (!object_cache_index_map_.LookupOrInsert(heap_object, &index)) {
31 // This object is not part of the object cache yet. Add it to the cache so
32 // we can refer to it via cache index from the delegating snapshot.
33 SerializeObject(heap_object);
34 }
35 return index;
36 }
37
Synchronize(VisitorSynchronization::SyncTag tag)38 void RootsSerializer::Synchronize(VisitorSynchronization::SyncTag tag) {
39 sink_.Put(kSynchronize, "Synchronize");
40 }
41
VisitRootPointers(Root root,const char * description,FullObjectSlot start,FullObjectSlot end)42 void RootsSerializer::VisitRootPointers(Root root, const char* description,
43 FullObjectSlot start,
44 FullObjectSlot end) {
45 RootsTable& roots_table = isolate()->roots_table();
46 if (start ==
47 roots_table.begin() + static_cast<int>(first_root_to_be_serialized_)) {
48 // Serializing the root list needs special handling:
49 // - Only root list elements that have been fully serialized can be
50 // referenced using kRootArray bytecodes.
51 for (FullObjectSlot current = start; current < end; ++current) {
52 SerializeRootObject(current);
53 size_t root_index = current - roots_table.begin();
54 root_has_been_serialized_.set(root_index);
55 }
56 } else {
57 Serializer::VisitRootPointers(root, description, start, end);
58 }
59 }
60
CheckRehashability(HeapObject obj)61 void RootsSerializer::CheckRehashability(HeapObject obj) {
62 if (!can_be_rehashed_) return;
63 if (!obj.NeedsRehashing()) return;
64 if (obj.CanBeRehashed()) return;
65 can_be_rehashed_ = false;
66 }
67
68 } // namespace internal
69 } // namespace v8
70