1 // Copyright 2017 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/parsing/preparsed-scope-data.h"
6
7 #include "src/ast/scopes.h"
8 #include "src/ast/variables.h"
9 #include "src/objects-inl.h"
10
11 namespace v8 {
12 namespace internal {
13
HasVariablesWhichNeedAllocationData(Scope * scope)14 bool PreParsedScopeData::HasVariablesWhichNeedAllocationData(Scope* scope) {
15 if (!scope->is_hidden()) {
16 for (Variable* var : *scope->locals()) {
17 if (var->mode() == VAR || var->mode() == LET || var->mode() == CONST) {
18 return true;
19 }
20 }
21 }
22 for (Scope* inner = scope->inner_scope(); inner != nullptr;
23 inner = inner->sibling()) {
24 if (HasVariablesWhichNeedAllocationData(inner)) {
25 return true;
26 }
27 }
28 return false;
29 }
30
ScopeScope(PreParsedScopeData * data,ScopeType scope_type,int start_position,int end_position)31 PreParsedScopeData::ScopeScope::ScopeScope(PreParsedScopeData* data,
32 ScopeType scope_type,
33 int start_position, int end_position)
34 : data_(data), previous_scope_(data->current_scope_) {
35 data->current_scope_ = this;
36 data->backing_store_.push_back(scope_type);
37 data->backing_store_.push_back(start_position);
38 data->backing_store_.push_back(end_position);
39 // Reserve space for variable and inner scope count (we don't know yet how
40 // many will be added).
41 index_in_data_ = data->backing_store_.size();
42 data->backing_store_.push_back(-1);
43 data->backing_store_.push_back(-1);
44 }
45
~ScopeScope()46 PreParsedScopeData::ScopeScope::~ScopeScope() {
47 data_->current_scope_ = previous_scope_;
48 if (got_data_) {
49 DCHECK_GT(variable_count_ + inner_scope_count_, 0);
50 if (previous_scope_ != nullptr) {
51 previous_scope_->got_data_ = true;
52 ++previous_scope_->inner_scope_count_;
53 }
54 data_->backing_store_[index_in_data_] = inner_scope_count_;
55 data_->backing_store_[index_in_data_ + 1] = variable_count_;
56 } else {
57 // No interesting data for this scope (or its children); remove from the
58 // data.
59 DCHECK_EQ(data_->backing_store_.size(), index_in_data_ + 2);
60 DCHECK_GE(index_in_data_, 3);
61 DCHECK_EQ(variable_count_, 0);
62 data_->backing_store_.erase(
63 data_->backing_store_.begin() + index_in_data_ - 3,
64 data_->backing_store_.end());
65 }
66 }
67
MaybeAddVariable(Variable * var)68 void PreParsedScopeData::ScopeScope::MaybeAddVariable(Variable* var) {
69 if (var->mode() == VAR || var->mode() == LET || var->mode() == CONST) {
70 #ifdef DEBUG
71 // For tests (which check that the data is about the same variables).
72 const AstRawString* name = var->raw_name();
73 data_->backing_store_.push_back(name->length());
74 for (int i = 0; i < name->length(); ++i) {
75 data_->backing_store_.push_back(name->raw_data()[i]);
76 }
77 #endif
78 data_->backing_store_.push_back(var->location());
79 data_->backing_store_.push_back(var->maybe_assigned());
80 ++variable_count_;
81 got_data_ = true;
82 }
83 }
84
85 } // namespace internal
86 } // namespace v8
87