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1 // Copyright 2006-2008 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 // The common functionality when building with or without snapshots. | |
6 | |
7 #include "src/v8.h" | |
8 | |
9 #include "src/api.h" | |
10 #include "src/base/platform/platform.h" | |
11 #include "src/full-codegen.h" | |
12 #include "src/snapshot.h" | |
13 | |
14 namespace v8 { | |
15 namespace internal { | |
16 | |
17 #ifdef DEBUG | |
18 bool Snapshot::SnapshotIsValid(v8::StartupData* snapshot_blob) { | |
19 return !Snapshot::ExtractStartupData(snapshot_blob).is_empty() && | |
20 !Snapshot::ExtractContextData(snapshot_blob).is_empty(); | |
21 } | |
22 #endif // DEBUG | |
23 | |
24 | |
25 bool Snapshot::EmbedsScript(Isolate* isolate) { | |
26 if (!isolate->snapshot_available()) return false; | |
27 return ExtractMetadata(isolate->snapshot_blob()).embeds_script(); | |
28 } | |
29 | |
30 | |
31 uint32_t Snapshot::SizeOfFirstPage(Isolate* isolate, AllocationSpace space) { | |
32 DCHECK(space >= FIRST_PAGED_SPACE && space <= LAST_PAGED_SPACE); | |
33 if (!isolate->snapshot_available()) { | |
34 return static_cast<uint32_t>(MemoryAllocator::PageAreaSize(space)); | |
35 } | |
36 uint32_t size; | |
37 int offset = kFirstPageSizesOffset + (space - FIRST_PAGED_SPACE) * kInt32Size; | |
38 memcpy(&size, isolate->snapshot_blob()->data + offset, kInt32Size); | |
39 return size; | |
40 } | |
41 | |
42 | |
43 bool Snapshot::Initialize(Isolate* isolate) { | |
44 if (!isolate->snapshot_available()) return false; | |
45 base::ElapsedTimer timer; | |
46 if (FLAG_profile_deserialization) timer.Start(); | |
47 | |
48 const v8::StartupData* blob = isolate->snapshot_blob(); | |
49 Vector<const byte> startup_data = ExtractStartupData(blob); | |
50 SnapshotData snapshot_data(startup_data); | |
51 Deserializer deserializer(&snapshot_data); | |
52 bool success = isolate->Init(&deserializer); | |
53 if (FLAG_profile_deserialization) { | |
54 double ms = timer.Elapsed().InMillisecondsF(); | |
55 int bytes = startup_data.length(); | |
56 PrintF("[Deserializing isolate (%d bytes) took %0.3f ms]\n", bytes, ms); | |
57 } | |
58 return success; | |
59 } | |
60 | |
61 | |
62 MaybeHandle<Context> Snapshot::NewContextFromSnapshot( | |
63 Isolate* isolate, Handle<JSGlobalProxy> global_proxy, | |
64 Handle<FixedArray>* outdated_contexts_out) { | |
65 if (!isolate->snapshot_available()) return Handle<Context>(); | |
66 base::ElapsedTimer timer; | |
67 if (FLAG_profile_deserialization) timer.Start(); | |
68 | |
69 const v8::StartupData* blob = isolate->snapshot_blob(); | |
70 Vector<const byte> context_data = ExtractContextData(blob); | |
71 SnapshotData snapshot_data(context_data); | |
72 Deserializer deserializer(&snapshot_data); | |
73 | |
74 MaybeHandle<Object> maybe_context = deserializer.DeserializePartial( | |
75 isolate, global_proxy, outdated_contexts_out); | |
76 Handle<Object> result; | |
77 if (!maybe_context.ToHandle(&result)) return MaybeHandle<Context>(); | |
78 CHECK(result->IsContext()); | |
79 // If the snapshot does not contain a custom script, we need to update | |
80 // the global object for exactly one context. | |
81 CHECK(EmbedsScript(isolate) || (*outdated_contexts_out)->length() == 1); | |
82 if (FLAG_profile_deserialization) { | |
83 double ms = timer.Elapsed().InMillisecondsF(); | |
84 int bytes = context_data.length(); | |
85 PrintF("[Deserializing context (%d bytes) took %0.3f ms]\n", bytes, ms); | |
86 } | |
87 return Handle<Context>::cast(result); | |
88 } | |
89 | |
90 | |
91 void CalculateFirstPageSizes(bool is_default_snapshot, | |
92 const SnapshotData& startup_snapshot, | |
93 const SnapshotData& context_snapshot, | |
94 uint32_t* sizes_out) { | |
95 Vector<const SerializedData::Reservation> startup_reservations = | |
96 startup_snapshot.Reservations(); | |
97 Vector<const SerializedData::Reservation> context_reservations = | |
98 context_snapshot.Reservations(); | |
99 int startup_index = 0; | |
100 int context_index = 0; | |
101 | |
102 if (FLAG_profile_deserialization) { | |
103 int startup_total = 0; | |
104 int context_total = 0; | |
105 for (auto& reservation : startup_reservations) { | |
106 startup_total += reservation.chunk_size(); | |
107 } | |
108 for (auto& reservation : context_reservations) { | |
109 context_total += reservation.chunk_size(); | |
110 } | |
111 PrintF( | |
112 "Deserialization will reserve:\n" | |
113 "%10d bytes for startup\n" | |
114 "%10d bytes per context\n", | |
115 startup_total, context_total); | |
116 } | |
117 | |
118 for (int space = 0; space < i::Serializer::kNumberOfSpaces; space++) { | |
119 bool single_chunk = true; | |
120 while (!startup_reservations[startup_index].is_last()) { | |
121 single_chunk = false; | |
122 startup_index++; | |
123 } | |
124 while (!context_reservations[context_index].is_last()) { | |
125 single_chunk = false; | |
126 context_index++; | |
127 } | |
128 | |
129 uint32_t required = kMaxUInt32; | |
130 if (single_chunk) { | |
131 // If both the startup snapshot data and the context snapshot data on | |
132 // this space fit in a single page, then we consider limiting the size | |
133 // of the first page. For this, we add the chunk sizes and some extra | |
134 // allowance. This way we achieve a smaller startup memory footprint. | |
135 required = (startup_reservations[startup_index].chunk_size() + | |
136 2 * context_reservations[context_index].chunk_size()) + | |
137 Page::kObjectStartOffset; | |
138 // Add a small allowance to the code space for small scripts. | |
139 if (space == CODE_SPACE) required += 32 * KB; | |
140 } else { | |
141 // We expect the vanilla snapshot to only require on page per space. | |
142 DCHECK(!is_default_snapshot); | |
143 } | |
144 | |
145 if (space >= FIRST_PAGED_SPACE && space <= LAST_PAGED_SPACE) { | |
146 uint32_t max_size = | |
147 MemoryAllocator::PageAreaSize(static_cast<AllocationSpace>(space)); | |
148 sizes_out[space - FIRST_PAGED_SPACE] = Min(required, max_size); | |
149 } else { | |
150 DCHECK(single_chunk); | |
151 } | |
152 startup_index++; | |
153 context_index++; | |
154 } | |
155 | |
156 DCHECK_EQ(startup_reservations.length(), startup_index); | |
157 DCHECK_EQ(context_reservations.length(), context_index); | |
158 } | |
159 | |
160 | |
161 v8::StartupData Snapshot::CreateSnapshotBlob( | |
162 const i::StartupSerializer& startup_ser, | |
163 const i::PartialSerializer& context_ser, Snapshot::Metadata metadata) { | |
164 SnapshotData startup_snapshot(startup_ser); | |
165 SnapshotData context_snapshot(context_ser); | |
166 Vector<const byte> startup_data = startup_snapshot.RawData(); | |
167 Vector<const byte> context_data = context_snapshot.RawData(); | |
168 | |
169 uint32_t first_page_sizes[kNumPagedSpaces]; | |
170 | |
171 CalculateFirstPageSizes(!metadata.embeds_script(), startup_snapshot, | |
172 context_snapshot, first_page_sizes); | |
173 | |
174 int startup_length = startup_data.length(); | |
175 int context_length = context_data.length(); | |
176 int context_offset = ContextOffset(startup_length); | |
177 | |
178 int length = context_offset + context_length; | |
179 char* data = new char[length]; | |
180 | |
181 memcpy(data + kMetadataOffset, &metadata.RawValue(), kInt32Size); | |
182 memcpy(data + kFirstPageSizesOffset, first_page_sizes, | |
183 kNumPagedSpaces * kInt32Size); | |
184 memcpy(data + kStartupLengthOffset, &startup_length, kInt32Size); | |
185 memcpy(data + kStartupDataOffset, startup_data.begin(), startup_length); | |
186 memcpy(data + context_offset, context_data.begin(), context_length); | |
187 v8::StartupData result = {data, length}; | |
188 | |
189 if (FLAG_profile_deserialization) { | |
190 PrintF( | |
191 "Snapshot blob consists of:\n" | |
192 "%10d bytes for startup\n" | |
193 "%10d bytes for context\n", | |
194 startup_length, context_length); | |
195 } | |
196 return result; | |
197 } | |
198 | |
199 | |
200 Snapshot::Metadata Snapshot::ExtractMetadata(const v8::StartupData* data) { | |
201 uint32_t raw; | |
202 memcpy(&raw, data->data + kMetadataOffset, kInt32Size); | |
203 return Metadata(raw); | |
204 } | |
205 | |
206 | |
207 Vector<const byte> Snapshot::ExtractStartupData(const v8::StartupData* data) { | |
208 DCHECK_LT(kIntSize, data->raw_size); | |
209 int startup_length; | |
210 memcpy(&startup_length, data->data + kStartupLengthOffset, kInt32Size); | |
211 DCHECK_LT(startup_length, data->raw_size); | |
212 const byte* startup_data = | |
213 reinterpret_cast<const byte*>(data->data + kStartupDataOffset); | |
214 return Vector<const byte>(startup_data, startup_length); | |
215 } | |
216 | |
217 | |
218 Vector<const byte> Snapshot::ExtractContextData(const v8::StartupData* data) { | |
219 DCHECK_LT(kIntSize, data->raw_size); | |
220 int startup_length; | |
221 memcpy(&startup_length, data->data + kStartupLengthOffset, kIntSize); | |
222 int context_offset = ContextOffset(startup_length); | |
223 const byte* context_data = | |
224 reinterpret_cast<const byte*>(data->data + context_offset); | |
225 DCHECK_LT(context_offset, data->raw_size); | |
226 int context_length = data->raw_size - context_offset; | |
227 return Vector<const byte>(context_data, context_length); | |
228 } | |
229 } } // namespace v8::internal | |
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