OLD | NEW |
---|---|
1 // Copyright 2012 the V8 project authors. All rights reserved. | 1 // Copyright 2012 the V8 project authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "src/rewriter.h" | 5 #include "src/rewriter.h" |
6 | 6 |
7 #include "src/ast.h" | 7 #include "src/ast.h" |
8 #include "src/parser.h" | 8 #include "src/parser.h" |
9 #include "src/scopes.h" | 9 #include "src/scopes.h" |
10 | 10 |
11 namespace v8 { | 11 namespace v8 { |
12 namespace internal { | 12 namespace internal { |
13 | 13 |
14 class Processor: public AstVisitor { | 14 class Processor: public AstVisitor { |
15 public: | 15 public: |
16 Processor(Isolate* isolate, Scope* scope, Variable* result, | 16 Processor(Isolate* isolate, Scope* scope, Variable* result, |
17 AstValueFactory* ast_value_factory) | 17 AstValueFactory* ast_value_factory) |
18 : result_(result), | 18 : result_(result), |
19 result_assigned_(false), | 19 result_assigned_(false), |
20 replacement_(nullptr), | 20 replacement_(nullptr), |
21 is_set_(false), | 21 is_set_(false), |
22 scope_(scope), | 22 scope_(scope), |
23 factory_(ast_value_factory) { | 23 factory_(ast_value_factory) { |
24 InitializeAstVisitor(isolate, ast_value_factory->zone()); | 24 InitializeAstVisitor(isolate, ast_value_factory->zone()); |
25 } | 25 } |
26 | 26 |
27 Processor(Parser* parser, Scope* scope, Variable* result, | |
28 AstValueFactory* ast_value_factory) | |
29 : result_(result), | |
30 result_assigned_(false), | |
31 replacement_(nullptr), | |
32 is_set_(false), | |
33 scope_(scope), | |
34 factory_(ast_value_factory) { | |
35 InitializeAstVisitor(nullptr, ast_value_factory->zone()); | |
36 parser_ = parser; | |
37 } | |
38 | |
27 virtual ~Processor() { } | 39 virtual ~Processor() { } |
28 | 40 |
29 void Process(ZoneList<Statement*>* statements); | 41 void Process(ZoneList<Statement*>* statements); |
30 bool result_assigned() const { return result_assigned_; } | 42 bool result_assigned() const { return result_assigned_; } |
31 | 43 |
32 Scope* scope() { return scope_; } | 44 Scope* scope() { return scope_; } |
33 AstNodeFactory* factory() { return &factory_; } | 45 AstNodeFactory* factory() { return &factory_; } |
34 | 46 |
47 // Returns ".result = value" | |
rossberg
2015/10/13 10:44:33
Why are these public now?
caitp (gmail)
2015/10/13 15:05:59
SetResult is used by the do expression rewriter, i
| |
48 Expression* SetResult(Expression* value) { | |
49 result_assigned_ = true; | |
50 VariableProxy* result_proxy = factory()->NewVariableProxy(result_); | |
51 return factory()->NewAssignment(Token::ASSIGN, result_proxy, value, | |
52 RelocInfo::kNoPosition); | |
53 } | |
54 | |
55 // Inserts '.result = undefined' in front of the given statement. | |
56 Statement* AssignUndefinedBefore(Statement* s); | |
57 | |
35 private: | 58 private: |
36 Variable* result_; | 59 Variable* result_; |
37 | 60 |
38 // We are not tracking result usage via the result_'s use | 61 // We are not tracking result usage via the result_'s use |
39 // counts (we leave the accurate computation to the | 62 // counts (we leave the accurate computation to the |
40 // usage analyzer). Instead we simple remember if | 63 // usage analyzer). Instead we simple remember if |
41 // there was ever an assignment to result_. | 64 // there was ever an assignment to result_. |
42 bool result_assigned_; | 65 bool result_assigned_; |
43 | 66 |
44 // When visiting a node, we "return" a replacement for that node in | 67 // When visiting a node, we "return" a replacement for that node in |
45 // [replacement_]. In many cases this will just be the original node. | 68 // [replacement_]. In many cases this will just be the original node. |
46 Statement* replacement_; | 69 Statement* replacement_; |
47 | 70 |
48 // To avoid storing to .result all the time, we eliminate some of | 71 // To avoid storing to .result all the time, we eliminate some of |
49 // the stores by keeping track of whether or not we're sure .result | 72 // the stores by keeping track of whether or not we're sure .result |
50 // will be overwritten anyway. This is a bit more tricky than what I | 73 // will be overwritten anyway. This is a bit more tricky than what I |
51 // was hoping for. | 74 // was hoping for. |
52 bool is_set_; | 75 bool is_set_; |
53 | 76 |
54 Scope* scope_; | 77 Scope* scope_; |
55 AstNodeFactory factory_; | 78 AstNodeFactory factory_; |
56 | 79 |
57 // Returns ".result = value" | |
58 Expression* SetResult(Expression* value) { | |
59 result_assigned_ = true; | |
60 VariableProxy* result_proxy = factory()->NewVariableProxy(result_); | |
61 return factory()->NewAssignment( | |
62 Token::ASSIGN, result_proxy, value, RelocInfo::kNoPosition); | |
63 } | |
64 | |
65 // Inserts '.result = undefined' in front of the given statement. | |
66 Statement* AssignUndefinedBefore(Statement* s); | |
67 | |
68 // Node visitors. | 80 // Node visitors. |
69 #define DEF_VISIT(type) virtual void Visit##type(type* node) override; | 81 #define DEF_VISIT(type) virtual void Visit##type(type* node) override; |
70 AST_NODE_LIST(DEF_VISIT) | 82 AST_NODE_LIST(DEF_VISIT) |
71 #undef DEF_VISIT | 83 #undef DEF_VISIT |
72 | 84 |
73 void VisitIterationStatement(IterationStatement* stmt); | 85 void VisitIterationStatement(IterationStatement* stmt); |
74 | 86 |
75 DEFINE_AST_VISITOR_SUBCLASS_MEMBERS(); | 87 public: |
88 void Visit(AstNode* node) final { | |
89 if (!CheckStackOverflow()) node->Accept(this); | |
90 } | |
91 | |
92 void SetStackOverflow() { stack_overflow_ = true; } | |
93 void ClearStackOverflow() { stack_overflow_ = false; } | |
94 bool HasStackOverflow() const { return stack_overflow_; } | |
95 | |
96 bool CheckStackOverflow() { | |
97 if (stack_overflow_) return true; | |
98 if (isolate_) { | |
99 StackLimitCheck check(isolate_); | |
100 if (!check.HasOverflowed()) return false; | |
101 stack_overflow_ = true; | |
102 } else { | |
103 if (!parser_->CheckStackOverflow()) return false; | |
104 stack_overflow_ = true; | |
105 } | |
106 return true; | |
107 } | |
108 | |
109 private: | |
110 void InitializeAstVisitor(Isolate* isolate, Zone* zone) { | |
111 isolate_ = isolate; | |
112 zone_ = zone; | |
113 stack_overflow_ = false; | |
114 } | |
115 Zone* zone() { return zone_; } | |
116 Isolate* isolate() { return isolate_; } | |
117 | |
118 Isolate* isolate_; | |
119 Parser* parser_; | |
120 Zone* zone_; | |
121 bool stack_overflow_; | |
76 }; | 122 }; |
77 | 123 |
78 | 124 |
79 Statement* Processor::AssignUndefinedBefore(Statement* s) { | 125 Statement* Processor::AssignUndefinedBefore(Statement* s) { |
80 Expression* result_proxy = factory()->NewVariableProxy(result_); | 126 Expression* result_proxy = factory()->NewVariableProxy(result_); |
81 Expression* undef = factory()->NewUndefinedLiteral(RelocInfo::kNoPosition); | 127 Expression* undef = factory()->NewUndefinedLiteral(RelocInfo::kNoPosition); |
82 Expression* assignment = factory()->NewAssignment( | 128 Expression* assignment = factory()->NewAssignment( |
83 Token::ASSIGN, result_proxy, undef, RelocInfo::kNoPosition); | 129 Token::ASSIGN, result_proxy, undef, RelocInfo::kNoPosition); |
84 Block* b = factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition); | 130 Block* b = factory()->NewBlock(NULL, 2, false, RelocInfo::kNoPosition); |
85 b->statements()->Add( | 131 b->statements()->Add( |
(...skipping 266 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... | |
352 Statement* result_statement = | 398 Statement* result_statement = |
353 processor.factory()->NewReturnStatement(result_proxy, pos); | 399 processor.factory()->NewReturnStatement(result_proxy, pos); |
354 body->Add(result_statement, info->zone()); | 400 body->Add(result_statement, info->zone()); |
355 } | 401 } |
356 } | 402 } |
357 | 403 |
358 return true; | 404 return true; |
359 } | 405 } |
360 | 406 |
361 | 407 |
408 bool Rewriter::Rewrite(Parser* parser, DoExpression* expr, | |
409 AstValueFactory* factory) { | |
410 Block* block = expr->block(); | |
411 Scope* scope = block->scope(); | |
412 ZoneList<Statement*>* body = block->statements(); | |
413 VariableProxy* result = expr->result(); | |
414 Variable* result_var = result->var(); | |
415 | |
416 if (!body->is_empty()) { | |
417 Processor processor(parser, scope, result_var, factory); | |
418 processor.Process(body); | |
419 if (processor.HasStackOverflow()) return false; | |
420 | |
421 if (!processor.result_assigned()) { | |
422 AstNodeFactory* node_factory = processor.factory(); | |
423 Expression* undef = | |
424 node_factory->NewUndefinedLiteral(RelocInfo::kNoPosition); | |
425 Statement* completion = node_factory->NewExpressionStatement( | |
426 processor.SetResult(undef), expr->position()); | |
427 body->Add(completion, factory->zone()); | |
428 } | |
429 } | |
430 return true; | |
431 } | |
432 | |
433 | |
362 } // namespace internal | 434 } // namespace internal |
363 } // namespace v8 | 435 } // namespace v8 |
OLD | NEW |