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1 // Copyright 2014 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/background-parsing-task.h"
6 
7 #include "src/objects-inl.h"
8 #include "src/parsing/parser.h"
9 
10 namespace v8 {
11 namespace internal {
12 
Release()13 void StreamedSource::Release() {
14   parser.reset();
15   info.reset();
16 }
17 
BackgroundParsingTask(StreamedSource * source,ScriptCompiler::CompileOptions options,int stack_size,Isolate * isolate)18 BackgroundParsingTask::BackgroundParsingTask(
19     StreamedSource* source, ScriptCompiler::CompileOptions options,
20     int stack_size, Isolate* isolate)
21     : source_(source), stack_size_(stack_size), script_data_(nullptr) {
22   // We don't set the context to the CompilationInfo yet, because the background
23   // thread cannot do anything with it anyway. We set it just before compilation
24   // on the foreground thread.
25   DCHECK(options == ScriptCompiler::kProduceParserCache ||
26          options == ScriptCompiler::kProduceCodeCache ||
27          options == ScriptCompiler::kNoCompileOptions);
28 
29   // Prepare the data for the internalization phase and compilation phase, which
30   // will happen in the main thread after parsing.
31   ParseInfo* info = new ParseInfo(isolate->allocator());
32   info->set_toplevel();
33   source->info.reset(info);
34   info->set_isolate(isolate);
35   info->set_source_stream(source->source_stream.get());
36   info->set_source_stream_encoding(source->encoding);
37   info->set_hash_seed(isolate->heap()->HashSeed());
38   info->set_unicode_cache(&source_->unicode_cache);
39   info->set_compile_options(options);
40   info->set_allow_lazy_parsing();
41 
42   source_->info->set_cached_data(&script_data_);
43   // Parser needs to stay alive for finalizing the parsing on the main
44   // thread.
45   source_->parser.reset(new Parser(source_->info.get()));
46   source_->parser->DeserializeScopeChain(source_->info.get(),
47                                          MaybeHandle<ScopeInfo>());
48 }
49 
50 
Run()51 void BackgroundParsingTask::Run() {
52   DisallowHeapAllocation no_allocation;
53   DisallowHandleAllocation no_handles;
54   DisallowHandleDereference no_deref;
55 
56   // Reset the stack limit of the parser to reflect correctly that we're on a
57   // background thread.
58   uintptr_t stack_limit = GetCurrentStackPosition() - stack_size_ * KB;
59   source_->parser->set_stack_limit(stack_limit);
60 
61   // Nullify the Isolate temporarily so that the background parser doesn't
62   // accidentally use it.
63   Isolate* isolate = source_->info->isolate();
64   source_->info->set_isolate(nullptr);
65 
66   source_->parser->ParseOnBackground(source_->info.get());
67 
68   if (script_data_ != nullptr) {
69     source_->cached_data.reset(new ScriptCompiler::CachedData(
70         script_data_->data(), script_data_->length(),
71         ScriptCompiler::CachedData::BufferOwned));
72     script_data_->ReleaseDataOwnership();
73     delete script_data_;
74     script_data_ = nullptr;
75   }
76   source_->info->set_isolate(isolate);
77 }
78 }  // namespace internal
79 }  // namespace v8
80