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, 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 factory_(ast_value_factory) { | 23 factory_(ast_value_factory) { |
23 InitializeAstVisitor(isolate, ast_value_factory->zone()); | 24 InitializeAstVisitor(isolate, ast_value_factory->zone()); |
24 } | 25 } |
25 | 26 |
26 virtual ~Processor() { } | 27 virtual ~Processor() { } |
27 | 28 |
28 void Process(ZoneList<Statement*>* statements); | 29 void Process(ZoneList<Statement*>* statements); |
29 bool result_assigned() const { return result_assigned_; } | 30 bool result_assigned() const { return result_assigned_; } |
30 | 31 |
| 32 Scope* scope() { return scope_; } |
31 AstNodeFactory* factory() { return &factory_; } | 33 AstNodeFactory* factory() { return &factory_; } |
32 | 34 |
33 private: | 35 private: |
34 Variable* result_; | 36 Variable* result_; |
35 | 37 |
36 // We are not tracking result usage via the result_'s use | 38 // We are not tracking result usage via the result_'s use |
37 // counts (we leave the accurate computation to the | 39 // counts (we leave the accurate computation to the |
38 // usage analyzer). Instead we simple remember if | 40 // usage analyzer). Instead we simple remember if |
39 // there was ever an assignment to result_. | 41 // there was ever an assignment to result_. |
40 bool result_assigned_; | 42 bool result_assigned_; |
41 | 43 |
42 // When visiting a node, we "return" a replacement for that node in | 44 // When visiting a node, we "return" a replacement for that node in |
43 // [replacement_]. In many cases this will just be the original node. | 45 // [replacement_]. In many cases this will just be the original node. |
44 Statement* replacement_; | 46 Statement* replacement_; |
45 | 47 |
46 // To avoid storing to .result all the time, we eliminate some of | 48 // To avoid storing to .result all the time, we eliminate some of |
47 // the stores by keeping track of whether or not we're sure .result | 49 // the stores by keeping track of whether or not we're sure .result |
48 // will be overwritten anyway. This is a bit more tricky than what I | 50 // will be overwritten anyway. This is a bit more tricky than what I |
49 // was hoping for. | 51 // was hoping for. |
50 bool is_set_; | 52 bool is_set_; |
51 | 53 |
| 54 Scope* scope_; |
52 AstNodeFactory factory_; | 55 AstNodeFactory factory_; |
53 | 56 |
| 57 // Returns ".result = value" |
54 Expression* SetResult(Expression* value) { | 58 Expression* SetResult(Expression* value) { |
55 result_assigned_ = true; | 59 result_assigned_ = true; |
56 VariableProxy* result_proxy = factory()->NewVariableProxy(result_); | 60 VariableProxy* result_proxy = factory()->NewVariableProxy(result_); |
57 return factory()->NewAssignment( | 61 return factory()->NewAssignment( |
58 Token::ASSIGN, result_proxy, value, RelocInfo::kNoPosition); | 62 Token::ASSIGN, result_proxy, value, RelocInfo::kNoPosition); |
59 } | 63 } |
60 | 64 |
61 // Node visitors. | 65 // Node visitors. |
62 #define DEF_VISIT(type) virtual void Visit##type(type* node) override; | 66 #define DEF_VISIT(type) virtual void Visit##type(type* node) override; |
63 AST_NODE_LIST(DEF_VISIT) | 67 AST_NODE_LIST(DEF_VISIT) |
(...skipping 96 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
160 is_set_ = set_after; | 164 is_set_ = set_after; |
161 Visit(node->catch_block()); | 165 Visit(node->catch_block()); |
162 node->set_catch_block(static_cast<Block*>(replacement_)); | 166 node->set_catch_block(static_cast<Block*>(replacement_)); |
163 is_set_ = is_set_ && set_in_try; | 167 is_set_ = is_set_ && set_in_try; |
164 replacement_ = node; | 168 replacement_ = node; |
165 } | 169 } |
166 | 170 |
167 | 171 |
168 void Processor::VisitTryFinallyStatement(TryFinallyStatement* node) { | 172 void Processor::VisitTryFinallyStatement(TryFinallyStatement* node) { |
169 // Rewrite both try and finally block (in reverse order). | 173 // Rewrite both try and finally block (in reverse order). |
| 174 bool set_after = is_set_; |
| 175 is_set_ = true; // Don't normally need to assign in finally block. |
170 Visit(node->finally_block()); | 176 Visit(node->finally_block()); |
171 node->set_finally_block(replacement_->AsBlock()); | 177 node->set_finally_block(replacement_->AsBlock()); |
172 Visit(node->try_block()); // Exception will not be caught. | 178 { // Save .result value at the beginning of the finally block and restore it |
| 179 // at the end again: ".backup = .result; ...; .result = .backup" |
| 180 // This is necessary because the finally block does not normally contribute |
| 181 // to the completion value. |
| 182 Variable* backup = scope()->NewTemporary( |
| 183 factory()->ast_value_factory()->dot_result_string()); |
| 184 Expression* backup_proxy = factory()->NewVariableProxy(backup); |
| 185 Expression* result_proxy = factory()->NewVariableProxy(result_); |
| 186 Expression* save = factory()->NewAssignment( |
| 187 Token::ASSIGN, backup_proxy, result_proxy, RelocInfo::kNoPosition); |
| 188 Expression* restore = factory()->NewAssignment( |
| 189 Token::ASSIGN, result_proxy, backup_proxy, RelocInfo::kNoPosition); |
| 190 node->finally_block()->statements()->InsertAt( |
| 191 0, factory()->NewExpressionStatement(save, RelocInfo::kNoPosition), |
| 192 zone()); |
| 193 node->finally_block()->statements()->Add( |
| 194 factory()->NewExpressionStatement(restore, RelocInfo::kNoPosition), |
| 195 zone()); |
| 196 } |
| 197 is_set_ = set_after; |
| 198 Visit(node->try_block()); |
173 node->set_try_block(replacement_->AsBlock()); | 199 node->set_try_block(replacement_->AsBlock()); |
174 replacement_ = node; | 200 replacement_ = node; |
175 } | 201 } |
176 | 202 |
177 | 203 |
178 void Processor::VisitSwitchStatement(SwitchStatement* node) { | 204 void Processor::VisitSwitchStatement(SwitchStatement* node) { |
179 // Rewrite statements in all case clauses (in reverse order). | 205 // Rewrite statements in all case clauses (in reverse order). |
180 ZoneList<CaseClause*>* clauses = node->cases(); | 206 ZoneList<CaseClause*>* clauses = node->cases(); |
181 bool set_after = is_set_; | 207 bool set_after = is_set_; |
182 for (int i = clauses->length() - 1; i >= 0; --i) { | 208 for (int i = clauses->length() - 1; i >= 0; --i) { |
(...skipping 70 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
253 Scope* scope = function->scope(); | 279 Scope* scope = function->scope(); |
254 DCHECK(scope != NULL); | 280 DCHECK(scope != NULL); |
255 if (!scope->is_script_scope() && !scope->is_eval_scope()) return true; | 281 if (!scope->is_script_scope() && !scope->is_eval_scope()) return true; |
256 | 282 |
257 ZoneList<Statement*>* body = function->body(); | 283 ZoneList<Statement*>* body = function->body(); |
258 if (!body->is_empty()) { | 284 if (!body->is_empty()) { |
259 Variable* result = | 285 Variable* result = |
260 scope->NewTemporary(info->ast_value_factory()->dot_result_string()); | 286 scope->NewTemporary(info->ast_value_factory()->dot_result_string()); |
261 // The name string must be internalized at this point. | 287 // The name string must be internalized at this point. |
262 DCHECK(!result->name().is_null()); | 288 DCHECK(!result->name().is_null()); |
263 Processor processor(info->isolate(), result, info->ast_value_factory()); | 289 Processor processor(info->isolate(), scope, result, |
| 290 info->ast_value_factory()); |
264 processor.Process(body); | 291 processor.Process(body); |
265 if (processor.HasStackOverflow()) return false; | 292 if (processor.HasStackOverflow()) return false; |
266 | 293 |
267 if (processor.result_assigned()) { | 294 if (processor.result_assigned()) { |
268 DCHECK(function->end_position() != RelocInfo::kNoPosition); | 295 DCHECK(function->end_position() != RelocInfo::kNoPosition); |
269 // Set the position of the assignment statement one character past the | 296 // Set the position of the assignment statement one character past the |
270 // source code, such that it definitely is not in the source code range | 297 // source code, such that it definitely is not in the source code range |
271 // of an immediate inner scope. For example in | 298 // of an immediate inner scope. For example in |
272 // eval('with ({x:1}) x = 1'); | 299 // eval('with ({x:1}) x = 1'); |
273 // the end position of the function generated for executing the eval code | 300 // the end position of the function generated for executing the eval code |
274 // coincides with the end of the with scope which is the position of '1'. | 301 // coincides with the end of the with scope which is the position of '1'. |
275 int pos = function->end_position(); | 302 int pos = function->end_position(); |
276 VariableProxy* result_proxy = | 303 VariableProxy* result_proxy = |
277 processor.factory()->NewVariableProxy(result, pos); | 304 processor.factory()->NewVariableProxy(result, pos); |
278 Statement* result_statement = | 305 Statement* result_statement = |
279 processor.factory()->NewReturnStatement(result_proxy, pos); | 306 processor.factory()->NewReturnStatement(result_proxy, pos); |
280 body->Add(result_statement, info->zone()); | 307 body->Add(result_statement, info->zone()); |
281 } | 308 } |
282 } | 309 } |
283 | 310 |
284 return true; | 311 return true; |
285 } | 312 } |
286 | 313 |
287 | 314 |
288 } // namespace internal | 315 } // namespace internal |
289 } // namespace v8 | 316 } // namespace v8 |
OLD | NEW |