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| 1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
| 2 // for details. All rights reserved. Use of this source code is governed by a | |
| 3 // BSD-style license that can be found in the LICENSE file. | |
| 4 | |
| 5 part of dart2js; | |
| 6 | |
| 7 /// A [ConstantEnvironment] provides access for constants compiled for variable | |
| 8 /// initializers. | |
| 9 abstract class ConstantEnvironment { | |
| 10 /// Returns the constant for the initializer of [element]. | |
| 11 ConstantExpression getConstantForVariable(VariableElement element); | |
| 12 } | |
| 13 | |
| 14 /// A class that can compile and provide constants for variables, nodes and | |
| 15 /// metadata. | |
| 16 abstract class ConstantCompiler extends ConstantEnvironment { | |
| 17 /// Compiles the compile-time constant for the initializer of [element], or | |
| 18 /// reports an error if the initializer is not a compile-time constant. | |
| 19 /// | |
| 20 /// Depending on implementation, the constant compiler might also compute | |
| 21 /// the compile-time constant for the backend interpretation of constants. | |
| 22 /// | |
| 23 /// The returned constant is always of the frontend interpretation. | |
| 24 ConstantExpression compileConstant(VariableElement element); | |
| 25 | |
| 26 /// Computes the compile-time constant for the variable initializer, | |
| 27 /// if possible. | |
| 28 void compileVariable(VariableElement element); | |
| 29 | |
| 30 /// Compiles the compile-time constant for [node], or reports an error if | |
| 31 /// [node] is not a compile-time constant. | |
| 32 /// | |
| 33 /// Depending on implementation, the constant compiler might also compute | |
| 34 /// the compile-time constant for the backend interpretation of constants. | |
| 35 /// | |
| 36 /// The returned constant is always of the frontend interpretation. | |
| 37 ConstantExpression compileNode(Node node, TreeElements elements); | |
| 38 | |
| 39 /// Compiles the compile-time constant for the value [metadata], or reports an | |
| 40 /// error if the value is not a compile-time constant. | |
| 41 /// | |
| 42 /// Depending on implementation, the constant compiler might also compute | |
| 43 /// the compile-time constant for the backend interpretation of constants. | |
| 44 /// | |
| 45 /// The returned constant is always of the frontend interpretation. | |
| 46 ConstantExpression compileMetadata(MetadataAnnotation metadata, | |
| 47 Node node, | |
| 48 TreeElements elements); | |
| 49 } | |
| 50 | |
| 51 /// A [BackendConstantEnvironment] provides access to constants needed for | |
| 52 /// backend implementation. | |
| 53 abstract class BackendConstantEnvironment extends ConstantEnvironment { | |
| 54 /// Returns the compile-time constant associated with [node]. | |
| 55 /// | |
| 56 /// Depending on implementation, the constant might be stored in [elements]. | |
| 57 ConstantExpression getConstantForNode(Node node, TreeElements elements); | |
| 58 | |
| 59 /// Returns the compile-time constant value of [metadata]. | |
| 60 ConstantExpression getConstantForMetadata(MetadataAnnotation metadata); | |
| 61 } | |
| 62 | |
| 63 /// Interface for the task that compiles the constant environments for the | |
| 64 /// frontend and backend interpretation of compile-time constants. | |
| 65 abstract class ConstantCompilerTask extends CompilerTask | |
| 66 implements ConstantCompiler { | |
| 67 ConstantCompilerTask(Compiler compiler) : super(compiler); | |
| 68 } | |
| 69 | |
| 70 /** | |
| 71 * The [ConstantCompilerBase] is provides base implementation for compilation of | |
| 72 * compile-time constants for both the Dart and JavaScript interpretation of | |
| 73 * constants. It keeps track of compile-time constants for initializations of | |
| 74 * global and static fields, and default values of optional parameters. | |
| 75 */ | |
| 76 abstract class ConstantCompilerBase implements ConstantCompiler { | |
| 77 final Compiler compiler; | |
| 78 final ConstantSystem constantSystem; | |
| 79 | |
| 80 /** | |
| 81 * Contains the initial values of fields and default values of parameters. | |
| 82 * | |
| 83 * Must contain all static and global initializations of const fields. | |
| 84 * | |
| 85 * May contain eagerly compiled initial values for statics and instance | |
| 86 * fields (if those are compile-time constants). | |
| 87 * | |
| 88 * May contain default parameter values of optional arguments. | |
| 89 * | |
| 90 * Invariant: The keys in this map are declarations. | |
| 91 */ | |
| 92 final Map<VariableElement, ConstantExpression> initialVariableValues = | |
| 93 new Map<VariableElement, ConstantExpression>(); | |
| 94 | |
| 95 /** The set of variable elements that are in the process of being computed. */ | |
| 96 final Set<VariableElement> pendingVariables = new Set<VariableElement>(); | |
| 97 | |
| 98 ConstantCompilerBase(this.compiler, this.constantSystem); | |
| 99 | |
| 100 ConstantExpression getConstantForVariable(VariableElement element) { | |
| 101 return initialVariableValues[element.declaration]; | |
| 102 } | |
| 103 | |
| 104 ConstantExpression compileConstant(VariableElement element) { | |
| 105 return compileVariable(element, isConst: true); | |
| 106 } | |
| 107 | |
| 108 ConstantExpression compileVariable(VariableElement element, | |
| 109 {bool isConst: false}) { | |
| 110 | |
| 111 if (initialVariableValues.containsKey(element.declaration)) { | |
| 112 ConstantExpression result = initialVariableValues[element.declaration]; | |
| 113 return result; | |
| 114 } | |
| 115 AstElement currentElement = element.analyzableElement; | |
| 116 return compiler.withCurrentElement(currentElement, () { | |
| 117 compiler.analyzeElement(currentElement.declaration); | |
| 118 ConstantExpression constant = compileVariableWithDefinitions( | |
| 119 element, currentElement.resolvedAst.elements, isConst: isConst); | |
| 120 return constant; | |
| 121 }); | |
| 122 } | |
| 123 | |
| 124 /** | |
| 125 * Returns the a compile-time constant if the variable could be compiled | |
| 126 * eagerly. If the variable needs to be initialized lazily returns `null`. | |
| 127 * If the variable is `const` but cannot be compiled eagerly reports an | |
| 128 * error. | |
| 129 */ | |
| 130 ConstantExpression compileVariableWithDefinitions(VariableElement element, | |
| 131 TreeElements definitions, | |
| 132 {bool isConst: false}) { | |
| 133 Node node = element.node; | |
| 134 if (pendingVariables.contains(element)) { | |
| 135 if (isConst) { | |
| 136 compiler.reportFatalError( | |
| 137 node, MessageKind.CYCLIC_COMPILE_TIME_CONSTANTS); | |
| 138 } | |
| 139 return null; | |
| 140 } | |
| 141 pendingVariables.add(element); | |
| 142 | |
| 143 Expression initializer = element.initializer; | |
| 144 ConstantExpression value; | |
| 145 if (initializer == null) { | |
| 146 // No initial value. | |
| 147 value = new PrimitiveConstantExpression(new NullConstantValue()); | |
| 148 } else { | |
| 149 value = compileNodeWithDefinitions( | |
| 150 initializer, definitions, isConst: isConst); | |
| 151 if (compiler.enableTypeAssertions && | |
| 152 value != null && | |
| 153 element.isField) { | |
| 154 DartType elementType = element.type; | |
| 155 if (elementType.isMalformed && !value.value.isNull) { | |
| 156 if (isConst) { | |
| 157 ErroneousElement element = elementType.element; | |
| 158 compiler.reportFatalError( | |
| 159 node, element.messageKind, element.messageArguments); | |
| 160 } else { | |
| 161 // We need to throw an exception at runtime. | |
| 162 value = null; | |
| 163 } | |
| 164 } else { | |
| 165 DartType constantType = value.value.computeType(compiler); | |
| 166 if (!constantSystem.isSubtype(compiler, | |
| 167 constantType, elementType)) { | |
| 168 if (isConst) { | |
| 169 compiler.reportFatalError( | |
| 170 node, MessageKind.NOT_ASSIGNABLE, | |
| 171 {'fromType': constantType, 'toType': elementType}); | |
| 172 } else { | |
| 173 // If the field cannot be lazily initialized, we will throw | |
| 174 // the exception at runtime. | |
| 175 value = null; | |
| 176 } | |
| 177 } | |
| 178 } | |
| 179 } | |
| 180 } | |
| 181 if (value != null) { | |
| 182 initialVariableValues[element.declaration] = value; | |
| 183 } else { | |
| 184 assert(invariant(element, !isConst, | |
| 185 message: "Variable $element does not compile to a constant.")); | |
| 186 } | |
| 187 pendingVariables.remove(element); | |
| 188 return value; | |
| 189 } | |
| 190 | |
| 191 ConstantExpression compileNodeWithDefinitions(Node node, | |
| 192 TreeElements definitions, | |
| 193 {bool isConst: true}) { | |
| 194 assert(node != null); | |
| 195 CompileTimeConstantEvaluator evaluator = new CompileTimeConstantEvaluator( | |
| 196 this, definitions, compiler, isConst: isConst); | |
| 197 AstConstant constant = evaluator.evaluate(node); | |
| 198 return constant != null ? constant.expression : null; | |
| 199 } | |
| 200 | |
| 201 ConstantExpression compileNode(Node node, TreeElements elements) { | |
| 202 return compileNodeWithDefinitions(node, elements); | |
| 203 } | |
| 204 | |
| 205 ConstantExpression compileMetadata(MetadataAnnotation metadata, | |
| 206 Node node, | |
| 207 TreeElements elements) { | |
| 208 return compileNodeWithDefinitions(node, elements); | |
| 209 } | |
| 210 | |
| 211 void forgetElement(Element element) { | |
| 212 initialVariableValues.remove(element); | |
| 213 if (element is ScopeContainerElement) { | |
| 214 element.forEachLocalMember(initialVariableValues.remove); | |
| 215 } | |
| 216 if (element is FunctionElement && element.hasFunctionSignature) { | |
| 217 element.functionSignature.forEachParameter(this.forgetElement); | |
| 218 } | |
| 219 } | |
| 220 } | |
| 221 | |
| 222 /// [ConstantCompiler] that uses the Dart semantics for the compile-time | |
| 223 /// constant evaluation. | |
| 224 class DartConstantCompiler extends ConstantCompilerBase { | |
| 225 DartConstantCompiler(Compiler compiler) | |
| 226 : super(compiler, const DartConstantSystem()); | |
| 227 | |
| 228 ConstantExpression getConstantForNode(Node node, TreeElements definitions) { | |
| 229 return definitions.getConstant(node); | |
| 230 } | |
| 231 | |
| 232 ConstantExpression getConstantForMetadata(MetadataAnnotation metadata) { | |
| 233 return metadata.constant; | |
| 234 } | |
| 235 | |
| 236 ConstantExpression compileNodeWithDefinitions(Node node, | |
| 237 TreeElements definitions, | |
| 238 {bool isConst: true}) { | |
| 239 ConstantExpression constant = definitions.getConstant(node); | |
| 240 if (constant != null) { | |
| 241 return constant; | |
| 242 } | |
| 243 constant = | |
| 244 super.compileNodeWithDefinitions(node, definitions, isConst: isConst); | |
| 245 if (constant != null) { | |
| 246 definitions.setConstant(node, constant); | |
| 247 } | |
| 248 return constant; | |
| 249 } | |
| 250 } | |
| 251 | |
| 252 // TODO(johnniwinther): Decouple the creation of [ConstExp] and [Constant] from | |
| 253 // front-end AST in order to reuse the evaluation for the shared front-end. | |
| 254 class CompileTimeConstantEvaluator extends Visitor<AstConstant> { | |
| 255 bool isEvaluatingConstant; | |
| 256 final ConstantCompilerBase handler; | |
| 257 final TreeElements elements; | |
| 258 final Compiler compiler; | |
| 259 | |
| 260 Element get context => elements.analyzedElement; | |
| 261 | |
| 262 CompileTimeConstantEvaluator(this.handler, | |
| 263 this.elements, | |
| 264 this.compiler, | |
| 265 {bool isConst: false}) | |
| 266 : this.isEvaluatingConstant = isConst; | |
| 267 | |
| 268 ConstantSystem get constantSystem => handler.constantSystem; | |
| 269 | |
| 270 AstConstant evaluate(Node node) { | |
| 271 return node.accept(this); | |
| 272 } | |
| 273 | |
| 274 AstConstant evaluateConstant(Node node) { | |
| 275 bool oldIsEvaluatingConstant = isEvaluatingConstant; | |
| 276 isEvaluatingConstant = true; | |
| 277 AstConstant result = node.accept(this); | |
| 278 isEvaluatingConstant = oldIsEvaluatingConstant; | |
| 279 assert(result != null); | |
| 280 return result; | |
| 281 } | |
| 282 | |
| 283 AstConstant visitNode(Node node) { | |
| 284 return signalNotCompileTimeConstant(node); | |
| 285 } | |
| 286 | |
| 287 AstConstant visitLiteralBool(LiteralBool node) { | |
| 288 return new AstConstant( | |
| 289 context, node, new PrimitiveConstantExpression( | |
| 290 constantSystem.createBool(node.value))); | |
| 291 } | |
| 292 | |
| 293 AstConstant visitLiteralDouble(LiteralDouble node) { | |
| 294 return new AstConstant( | |
| 295 context, node, new PrimitiveConstantExpression( | |
| 296 constantSystem.createDouble(node.value))); | |
| 297 } | |
| 298 | |
| 299 AstConstant visitLiteralInt(LiteralInt node) { | |
| 300 return new AstConstant( | |
| 301 context, node, new PrimitiveConstantExpression( | |
| 302 constantSystem.createInt(node.value))); | |
| 303 } | |
| 304 | |
| 305 AstConstant visitLiteralList(LiteralList node) { | |
| 306 if (!node.isConst) { | |
| 307 return signalNotCompileTimeConstant(node); | |
| 308 } | |
| 309 List<ConstantExpression> argumentExpressions = <ConstantExpression>[]; | |
| 310 List<ConstantValue> argumentValues = <ConstantValue>[]; | |
| 311 for (Link<Node> link = node.elements.nodes; | |
| 312 !link.isEmpty; | |
| 313 link = link.tail) { | |
| 314 AstConstant argument = evaluateConstant(link.head); | |
| 315 if (argument == null) { | |
| 316 return null; | |
| 317 } | |
| 318 argumentExpressions.add(argument.expression); | |
| 319 argumentValues.add(argument.value); | |
| 320 } | |
| 321 DartType type = elements.getType(node); | |
| 322 return new AstConstant( | |
| 323 context, node, new ListConstantExpression( | |
| 324 new ListConstantValue(type, argumentValues), | |
| 325 type, | |
| 326 argumentExpressions)); | |
| 327 } | |
| 328 | |
| 329 AstConstant visitLiteralMap(LiteralMap node) { | |
| 330 if (!node.isConst) { | |
| 331 return signalNotCompileTimeConstant(node); | |
| 332 } | |
| 333 List<ConstantExpression> keyExpressions = <ConstantExpression>[]; | |
| 334 List<ConstantValue> keyValues = <ConstantValue>[]; | |
| 335 Map<ConstantValue, ConstantExpression> map = | |
| 336 new Map<ConstantValue, ConstantExpression>(); | |
| 337 for (Link<Node> link = node.entries.nodes; | |
| 338 !link.isEmpty; | |
| 339 link = link.tail) { | |
| 340 LiteralMapEntry entry = link.head; | |
| 341 AstConstant key = evaluateConstant(entry.key); | |
| 342 if (key == null) { | |
| 343 return null; | |
| 344 } | |
| 345 if (!map.containsKey(key.value)) { | |
| 346 keyExpressions.add(key.expression); | |
| 347 keyValues.add(key.value); | |
| 348 } else { | |
| 349 compiler.reportWarning(entry.key, MessageKind.EQUAL_MAP_ENTRY_KEY); | |
| 350 } | |
| 351 AstConstant value = evaluateConstant(entry.value); | |
| 352 if (value == null) { | |
| 353 return null; | |
| 354 } | |
| 355 map[key.value] = value.expression; | |
| 356 } | |
| 357 List<ConstantExpression> valueExpressions = map.values.toList(); | |
| 358 InterfaceType type = elements.getType(node); | |
| 359 return new AstConstant( | |
| 360 context, node, new MapConstantExpression( | |
| 361 constantSystem.createMap(compiler, type, keyValues, | |
| 362 valueExpressions.map((e) => e.value).toList()), | |
| 363 type, | |
| 364 keyExpressions, | |
| 365 valueExpressions)); | |
| 366 } | |
| 367 | |
| 368 AstConstant visitLiteralNull(LiteralNull node) { | |
| 369 return new AstConstant( | |
| 370 context, node, new PrimitiveConstantExpression( | |
| 371 constantSystem.createNull())); | |
| 372 } | |
| 373 | |
| 374 AstConstant visitLiteralString(LiteralString node) { | |
| 375 return new AstConstant( | |
| 376 context, node, new PrimitiveConstantExpression( | |
| 377 constantSystem.createString(node.dartString))); | |
| 378 } | |
| 379 | |
| 380 AstConstant visitStringJuxtaposition(StringJuxtaposition node) { | |
| 381 AstConstant left = evaluate(node.first); | |
| 382 AstConstant right = evaluate(node.second); | |
| 383 if (left == null || right == null) return null; | |
| 384 StringConstantValue leftValue = left.value; | |
| 385 StringConstantValue rightValue = right.value; | |
| 386 return new AstConstant( | |
| 387 context, node, new ConcatenateConstantExpression( | |
| 388 constantSystem.createString( | |
| 389 new DartString.concat( | |
| 390 leftValue.primitiveValue, rightValue.primitiveValue)), | |
| 391 [left.expression, right.expression])); | |
| 392 } | |
| 393 | |
| 394 AstConstant visitStringInterpolation(StringInterpolation node) { | |
| 395 List<ConstantExpression> subexpressions = <ConstantExpression>[]; | |
| 396 AstConstant initialString = evaluate(node.string); | |
| 397 if (initialString == null) { | |
| 398 return null; | |
| 399 } | |
| 400 subexpressions.add(initialString.expression); | |
| 401 StringConstantValue initialStringValue = initialString.value; | |
| 402 DartString accumulator = initialStringValue.primitiveValue; | |
| 403 for (StringInterpolationPart part in node.parts) { | |
| 404 AstConstant subexpression = evaluate(part.expression); | |
| 405 if (subexpression == null) { | |
| 406 return null; | |
| 407 } | |
| 408 subexpressions.add(subexpression.expression); | |
| 409 ConstantValue expression = subexpression.value; | |
| 410 DartString expressionString; | |
| 411 if (expression.isNum || expression.isBool) { | |
| 412 PrimitiveConstantValue primitive = expression; | |
| 413 expressionString = | |
| 414 new DartString.literal(primitive.primitiveValue.toString()); | |
| 415 } else if (expression.isString) { | |
| 416 PrimitiveConstantValue primitive = expression; | |
| 417 expressionString = primitive.primitiveValue; | |
| 418 } else { | |
| 419 // TODO(johnniwinther): Specialize message to indicated that the problem | |
| 420 // is not constness but the types of the const expressions. | |
| 421 return signalNotCompileTimeConstant(part.expression); | |
| 422 } | |
| 423 accumulator = new DartString.concat(accumulator, expressionString); | |
| 424 AstConstant partString = evaluate(part.string); | |
| 425 if (partString == null) return null; | |
| 426 subexpressions.add(partString.expression); | |
| 427 StringConstantValue partStringValue = partString.value; | |
| 428 accumulator = | |
| 429 new DartString.concat(accumulator, partStringValue.primitiveValue); | |
| 430 }; | |
| 431 return new AstConstant( | |
| 432 context, node, new ConcatenateConstantExpression( | |
| 433 constantSystem.createString(accumulator), | |
| 434 subexpressions)); | |
| 435 } | |
| 436 | |
| 437 AstConstant visitLiteralSymbol(LiteralSymbol node) { | |
| 438 InterfaceType type = compiler.symbolClass.rawType; | |
| 439 String text = node.slowNameString; | |
| 440 List<AstConstant> arguments = | |
| 441 <AstConstant>[new AstConstant(context, node, | |
| 442 new PrimitiveConstantExpression(constantSystem.createString( | |
| 443 new DartString.literal(text))))]; | |
| 444 AstConstant constant = makeConstructedConstant( | |
| 445 compiler, handler, context, node, type, compiler.symbolConstructor, | |
| 446 new Selector.callConstructor('', null, 1), | |
| 447 arguments, arguments); | |
| 448 return new AstConstant( | |
| 449 context, node, new SymbolConstantExpression(constant.value, text)); | |
| 450 } | |
| 451 | |
| 452 AstConstant makeTypeConstant(Node node, DartType elementType) { | |
| 453 DartType constantType = | |
| 454 compiler.backend.typeImplementation.computeType(compiler); | |
| 455 return new AstConstant( | |
| 456 context, node, new TypeConstantExpression( | |
| 457 new TypeConstantValue(elementType, constantType), | |
| 458 elementType)); | |
| 459 } | |
| 460 | |
| 461 /// Returns true if the prefix of the send resolves to a deferred import | |
| 462 /// prefix. | |
| 463 bool isDeferredUse(Send send) { | |
| 464 if (send == null) return false; | |
| 465 return compiler.deferredLoadTask | |
| 466 .deferredPrefixElement(send, elements) != null; | |
| 467 } | |
| 468 | |
| 469 AstConstant visitIdentifier(Identifier node) { | |
| 470 Element element = elements[node]; | |
| 471 if (Elements.isClass(element) || Elements.isTypedef(element)) { | |
| 472 TypeDeclarationElement typeDeclarationElement = element; | |
| 473 DartType type = typeDeclarationElement.rawType; | |
| 474 return makeTypeConstant(node, type); | |
| 475 } | |
| 476 return signalNotCompileTimeConstant(node); | |
| 477 } | |
| 478 | |
| 479 // TODO(floitsch): provide better error-messages. | |
| 480 AstConstant visitSend(Send send) { | |
| 481 Element element = elements[send]; | |
| 482 if (send.isPropertyAccess) { | |
| 483 if (isDeferredUse(send)) { | |
| 484 return signalNotCompileTimeConstant(send, | |
| 485 message: MessageKind.DEFERRED_COMPILE_TIME_CONSTANT); | |
| 486 } | |
| 487 if (Elements.isStaticOrTopLevelFunction(element)) { | |
| 488 return new AstConstant( | |
| 489 context, send, new FunctionConstantExpression( | |
| 490 new FunctionConstantValue(element), | |
| 491 element)); | |
| 492 } else if (Elements.isStaticOrTopLevelField(element)) { | |
| 493 ConstantExpression result; | |
| 494 if (element.isConst) { | |
| 495 result = handler.compileConstant(element); | |
| 496 } else if (element.isFinal && !isEvaluatingConstant) { | |
| 497 result = handler.compileVariable(element); | |
| 498 } | |
| 499 if (result != null) { | |
| 500 return new AstConstant( | |
| 501 context, send, | |
| 502 new VariableConstantExpression(result.value, element)); | |
| 503 } | |
| 504 } else if (Elements.isClass(element) || Elements.isTypedef(element)) { | |
| 505 assert(elements.isTypeLiteral(send)); | |
| 506 return makeTypeConstant(send, elements.getTypeLiteralType(send)); | |
| 507 } else if (send.receiver != null) { | |
| 508 // Fall through to error handling. | |
| 509 } else if (!Elements.isUnresolved(element) | |
| 510 && element.isVariable | |
| 511 && element.isConst) { | |
| 512 ConstantExpression result = handler.compileConstant(element); | |
| 513 if (result != null) { | |
| 514 return new AstConstant( | |
| 515 context, send, | |
| 516 new VariableConstantExpression(result.value, element)); | |
| 517 } | |
| 518 } | |
| 519 return signalNotCompileTimeConstant(send); | |
| 520 } else if (send.isCall) { | |
| 521 if (identical(element, compiler.identicalFunction) | |
| 522 && send.argumentCount() == 2) { | |
| 523 AstConstant left = evaluate(send.argumentsNode.nodes.head); | |
| 524 AstConstant right = evaluate(send.argumentsNode.nodes.tail.head); | |
| 525 if (left == null || right == null) { | |
| 526 return null; | |
| 527 } | |
| 528 ConstantValue result = | |
| 529 constantSystem.identity.fold(left.value, right.value); | |
| 530 if (result != null) { | |
| 531 return new AstConstant( | |
| 532 context, send, new BinaryConstantExpression(result, | |
| 533 left.expression, 'identical', right.expression)); | |
| 534 } | |
| 535 } | |
| 536 return signalNotCompileTimeConstant(send); | |
| 537 } else if (send.isPrefix) { | |
| 538 assert(send.isOperator); | |
| 539 AstConstant receiverConstant = evaluate(send.receiver); | |
| 540 if (receiverConstant == null) { | |
| 541 return null; | |
| 542 } | |
| 543 Operator op = send.selector; | |
| 544 UnaryOperation operation = constantSystem.lookupUnary(op.source); | |
| 545 if (operation == null) { | |
| 546 compiler.internalError(op, "Unexpected operator."); | |
| 547 } | |
| 548 ConstantValue folded = operation.fold(receiverConstant.value); | |
| 549 if (folded == null) { | |
| 550 return signalNotCompileTimeConstant(send); | |
| 551 } | |
| 552 return new AstConstant( | |
| 553 context, send, new UnaryConstantExpression(folded, | |
| 554 op.source, receiverConstant.expression)); | |
| 555 } else if (send.isOperator && !send.isPostfix) { | |
| 556 assert(send.argumentCount() == 1); | |
| 557 AstConstant left = evaluate(send.receiver); | |
| 558 AstConstant right = evaluate(send.argumentsNode.nodes.head); | |
| 559 if (left == null || right == null) { | |
| 560 return null; | |
| 561 } | |
| 562 ConstantValue leftValue = left.value; | |
| 563 ConstantValue rightValue = right.value; | |
| 564 Operator op = send.selector.asOperator(); | |
| 565 ConstantValue folded = null; | |
| 566 switch (op.source) { | |
| 567 case "==": | |
| 568 if (leftValue.isPrimitive && rightValue.isPrimitive) { | |
| 569 folded = constantSystem.equal.fold(leftValue, rightValue); | |
| 570 } | |
| 571 break; | |
| 572 case "!=": | |
| 573 if (leftValue.isPrimitive && rightValue.isPrimitive) { | |
| 574 BoolConstantValue areEquals = | |
| 575 constantSystem.equal.fold(leftValue, rightValue); | |
| 576 if (areEquals == null) { | |
| 577 folded = null; | |
| 578 } else { | |
| 579 folded = areEquals.negate(); | |
| 580 } | |
| 581 } | |
| 582 break; | |
| 583 default: | |
| 584 BinaryOperation operation = constantSystem.lookupBinary(op.source); | |
| 585 if (operation != null) { | |
| 586 folded = operation.fold(leftValue, rightValue); | |
| 587 } | |
| 588 } | |
| 589 if (folded == null) { | |
| 590 return signalNotCompileTimeConstant(send); | |
| 591 } | |
| 592 return new AstConstant( | |
| 593 context, send, new BinaryConstantExpression(folded, | |
| 594 left.expression, op.source, right.expression)); | |
| 595 } | |
| 596 return signalNotCompileTimeConstant(send); | |
| 597 } | |
| 598 | |
| 599 AstConstant visitConditional(Conditional node) { | |
| 600 AstConstant condition = evaluate(node.condition); | |
| 601 if (condition == null) { | |
| 602 return null; | |
| 603 } else if (!condition.value.isBool) { | |
| 604 DartType conditionType = condition.value.computeType(compiler); | |
| 605 if (isEvaluatingConstant) { | |
| 606 compiler.reportFatalError( | |
| 607 node.condition, MessageKind.NOT_ASSIGNABLE, | |
| 608 {'fromType': conditionType, 'toType': compiler.boolClass.rawType}); | |
| 609 } | |
| 610 return null; | |
| 611 } | |
| 612 AstConstant thenExpression = evaluate(node.thenExpression); | |
| 613 AstConstant elseExpression = evaluate(node.elseExpression); | |
| 614 if (thenExpression == null || elseExpression == null) { | |
| 615 return null; | |
| 616 } | |
| 617 BoolConstantValue boolCondition = condition.value; | |
| 618 return new AstConstant( | |
| 619 context, node, new ConditionalConstantExpression( | |
| 620 boolCondition.primitiveValue | |
| 621 ? thenExpression.value | |
| 622 : elseExpression.value, | |
| 623 condition.expression, | |
| 624 thenExpression.expression, | |
| 625 elseExpression.expression)); | |
| 626 } | |
| 627 | |
| 628 AstConstant visitSendSet(SendSet node) { | |
| 629 return signalNotCompileTimeConstant(node); | |
| 630 } | |
| 631 | |
| 632 /** | |
| 633 * Returns the normalized list of constant arguments that are passed to the | |
| 634 * constructor including both the concrete arguments and default values for | |
| 635 * omitted optional arguments. | |
| 636 * | |
| 637 * Invariant: [target] must be an implementation element. | |
| 638 */ | |
| 639 List<AstConstant> evaluateArgumentsToConstructor( | |
| 640 Node node, | |
| 641 Selector selector, | |
| 642 Link<Node> arguments, | |
| 643 FunctionElement target, | |
| 644 {AstConstant compileArgument(Node node)}) { | |
| 645 assert(invariant(node, target.isImplementation)); | |
| 646 List<AstConstant> compiledArguments = <AstConstant>[]; | |
| 647 | |
| 648 AstConstant compileDefaultValue(VariableElement element) { | |
| 649 ConstantExpression constant = handler.compileConstant(element); | |
| 650 return new AstConstant.fromDefaultValue(element, constant); | |
| 651 } | |
| 652 target.computeSignature(compiler); | |
| 653 bool succeeded = selector.addArgumentsToList(arguments, | |
| 654 compiledArguments, | |
| 655 target, | |
| 656 compileArgument, | |
| 657 compileDefaultValue, | |
| 658 compiler.world); | |
| 659 if (!succeeded) { | |
| 660 String name = Elements.constructorNameForDiagnostics( | |
| 661 target.enclosingClass.name, target.name); | |
| 662 compiler.reportFatalError( | |
| 663 node, | |
| 664 MessageKind.INVALID_CONSTRUCTOR_ARGUMENTS, | |
| 665 {'constructorName': name}); | |
| 666 } | |
| 667 return compiledArguments; | |
| 668 } | |
| 669 | |
| 670 AstConstant visitNewExpression(NewExpression node) { | |
| 671 if (!node.isConst) { | |
| 672 return signalNotCompileTimeConstant(node); | |
| 673 } | |
| 674 | |
| 675 Send send = node.send; | |
| 676 FunctionElement constructor = elements[send]; | |
| 677 if (Elements.isUnresolved(constructor)) { | |
| 678 return signalNotCompileTimeConstant(node); | |
| 679 } | |
| 680 | |
| 681 // Deferred types can not be used in const instance creation expressions. | |
| 682 // Check if the constructor comes from a deferred library. | |
| 683 if (isDeferredUse(node.send.selector.asSend())) { | |
| 684 return signalNotCompileTimeConstant(node, | |
| 685 message: MessageKind.DEFERRED_COMPILE_TIME_CONSTANT_CONSTRUCTION); | |
| 686 } | |
| 687 | |
| 688 // TODO(ahe): This is nasty: we must eagerly analyze the | |
| 689 // constructor to ensure the redirectionTarget has been computed | |
| 690 // correctly. Find a way to avoid this. | |
| 691 compiler.analyzeElement(constructor.declaration); | |
| 692 | |
| 693 InterfaceType type = elements.getType(node); | |
| 694 Selector selector = elements.getSelector(send); | |
| 695 | |
| 696 Map<Node, AstConstant> concreteArgumentMap = | |
| 697 <Node, AstConstant>{}; | |
| 698 for (Link<Node> link = send.arguments; !link.isEmpty; link = link.tail) { | |
| 699 Node argument = link.head; | |
| 700 NamedArgument namedArgument = argument.asNamedArgument(); | |
| 701 if (namedArgument != null) { | |
| 702 argument = namedArgument.expression; | |
| 703 } | |
| 704 concreteArgumentMap[argument] = evaluateConstant(argument); | |
| 705 } | |
| 706 | |
| 707 List<AstConstant> normalizedArguments = | |
| 708 evaluateArgumentsToConstructor( | |
| 709 node, selector, send.arguments, constructor.implementation, | |
| 710 compileArgument: (node) => concreteArgumentMap[node]); | |
| 711 List<AstConstant> concreteArguments = | |
| 712 concreteArgumentMap.values.toList(); | |
| 713 | |
| 714 if (constructor == compiler.intEnvironment || | |
| 715 constructor == compiler.boolEnvironment || | |
| 716 constructor == compiler.stringEnvironment) { | |
| 717 | |
| 718 AstConstant createEvaluatedConstant(ConstantValue value) { | |
| 719 return new AstConstant( | |
| 720 context, node, new ConstructedConstantExpresssion( | |
| 721 value, | |
| 722 type, | |
| 723 constructor, | |
| 724 elements.getSelector(send), | |
| 725 concreteArguments.map((e) => e.expression).toList())); | |
| 726 } | |
| 727 | |
| 728 var firstArgument = normalizedArguments[0].value; | |
| 729 ConstantValue defaultValue = normalizedArguments[1].value; | |
| 730 | |
| 731 if (firstArgument.isNull) { | |
| 732 compiler.reportFatalError( | |
| 733 send.arguments.head, MessageKind.NULL_NOT_ALLOWED); | |
| 734 return null; | |
| 735 } | |
| 736 | |
| 737 if (!firstArgument.isString) { | |
| 738 DartType type = defaultValue.computeType(compiler); | |
| 739 compiler.reportFatalError( | |
| 740 send.arguments.head, MessageKind.NOT_ASSIGNABLE, | |
| 741 {'fromType': type, 'toType': compiler.stringClass.rawType}); | |
| 742 return null; | |
| 743 } | |
| 744 | |
| 745 if (constructor == compiler.intEnvironment && | |
| 746 !(defaultValue.isNull || defaultValue.isInt)) { | |
| 747 DartType type = defaultValue.computeType(compiler); | |
| 748 compiler.reportFatalError( | |
| 749 send.arguments.tail.head, MessageKind.NOT_ASSIGNABLE, | |
| 750 {'fromType': type, 'toType': compiler.intClass.rawType}); | |
| 751 return null; | |
| 752 } | |
| 753 | |
| 754 if (constructor == compiler.boolEnvironment && | |
| 755 !(defaultValue.isNull || defaultValue.isBool)) { | |
| 756 DartType type = defaultValue.computeType(compiler); | |
| 757 compiler.reportFatalError( | |
| 758 send.arguments.tail.head, MessageKind.NOT_ASSIGNABLE, | |
| 759 {'fromType': type, 'toType': compiler.boolClass.rawType}); | |
| 760 return null; | |
| 761 } | |
| 762 | |
| 763 if (constructor == compiler.stringEnvironment && | |
| 764 !(defaultValue.isNull || defaultValue.isString)) { | |
| 765 DartType type = defaultValue.computeType(compiler); | |
| 766 compiler.reportFatalError( | |
| 767 send.arguments.tail.head, MessageKind.NOT_ASSIGNABLE, | |
| 768 {'fromType': type, 'toType': compiler.stringClass.rawType}); | |
| 769 return null; | |
| 770 } | |
| 771 | |
| 772 String value = | |
| 773 compiler.fromEnvironment(firstArgument.primitiveValue.slowToString()); | |
| 774 | |
| 775 if (value == null) { | |
| 776 return createEvaluatedConstant(defaultValue); | |
| 777 } else if (constructor == compiler.intEnvironment) { | |
| 778 int number = int.parse(value, onError: (_) => null); | |
| 779 return createEvaluatedConstant( | |
| 780 (number == null) | |
| 781 ? defaultValue | |
| 782 : constantSystem.createInt(number)); | |
| 783 } else if (constructor == compiler.boolEnvironment) { | |
| 784 if (value == 'true') { | |
| 785 return createEvaluatedConstant(constantSystem.createBool(true)); | |
| 786 } else if (value == 'false') { | |
| 787 return createEvaluatedConstant(constantSystem.createBool(false)); | |
| 788 } else { | |
| 789 return createEvaluatedConstant(defaultValue); | |
| 790 } | |
| 791 } else { | |
| 792 assert(constructor == compiler.stringEnvironment); | |
| 793 return createEvaluatedConstant( | |
| 794 constantSystem.createString(new DartString.literal(value))); | |
| 795 } | |
| 796 } else { | |
| 797 return makeConstructedConstant( | |
| 798 compiler, handler, context, | |
| 799 node, type, constructor, selector, | |
| 800 concreteArguments, normalizedArguments); | |
| 801 } | |
| 802 } | |
| 803 | |
| 804 static AstConstant makeConstructedConstant( | |
| 805 Compiler compiler, | |
| 806 ConstantCompilerBase handler, | |
| 807 Element context, | |
| 808 Node node, | |
| 809 InterfaceType type, | |
| 810 ConstructorElement constructor, | |
| 811 Selector selector, | |
| 812 List<AstConstant> concreteArguments, | |
| 813 List<AstConstant> normalizedArguments) { | |
| 814 assert(invariant(node, selector.applies(constructor, compiler.world), | |
| 815 message: "Selector $selector does not apply to constructor " | |
| 816 "$constructor.")); | |
| 817 | |
| 818 // The redirection chain of this element may not have been resolved through | |
| 819 // a post-process action, so we have to make sure it is done here. | |
| 820 compiler.resolver.resolveRedirectionChain(constructor, node); | |
| 821 InterfaceType constructedType = | |
| 822 constructor.computeEffectiveTargetType(type); | |
| 823 ConstructorElement target = constructor.effectiveTarget; | |
| 824 ClassElement classElement = target.enclosingClass; | |
| 825 // The constructor must be an implementation to ensure that field | |
| 826 // initializers are handled correctly. | |
| 827 target = target.implementation; | |
| 828 assert(invariant(node, target.isImplementation)); | |
| 829 | |
| 830 ConstructorEvaluator evaluator = new ConstructorEvaluator( | |
| 831 constructedType, target, handler, compiler); | |
| 832 evaluator.evaluateConstructorFieldValues(normalizedArguments); | |
| 833 List<AstConstant> fieldConstants = | |
| 834 evaluator.buildFieldConstants(classElement); | |
| 835 | |
| 836 return new AstConstant( | |
| 837 context, node, new ConstructedConstantExpresssion( | |
| 838 new ConstructedConstantValue( | |
| 839 constructedType, | |
| 840 fieldConstants.map((e) => e.value).toList()), | |
| 841 type, | |
| 842 constructor, | |
| 843 selector, | |
| 844 concreteArguments.map((e) => e.expression).toList())); | |
| 845 } | |
| 846 | |
| 847 AstConstant visitParenthesizedExpression(ParenthesizedExpression node) { | |
| 848 return node.expression.accept(this); | |
| 849 } | |
| 850 | |
| 851 error(Node node, MessageKind message) { | |
| 852 // TODO(floitsch): get the list of constants that are currently compiled | |
| 853 // and present some kind of stack-trace. | |
| 854 compiler.reportFatalError(node, message); | |
| 855 } | |
| 856 | |
| 857 AstConstant signalNotCompileTimeConstant(Node node, | |
| 858 {MessageKind message: MessageKind.NOT_A_COMPILE_TIME_CONSTANT}) { | |
| 859 if (isEvaluatingConstant) { | |
| 860 error(node, message); | |
| 861 } | |
| 862 // Else we don't need to do anything. The final handler is only | |
| 863 // optimistically trying to compile constants. So it is normal that we | |
| 864 // sometimes see non-compile time constants. | |
| 865 // Simply return [:null:] which is used to propagate a failing | |
| 866 // compile-time compilation. | |
| 867 return null; | |
| 868 } | |
| 869 } | |
| 870 | |
| 871 class ConstructorEvaluator extends CompileTimeConstantEvaluator { | |
| 872 final InterfaceType constructedType; | |
| 873 final ConstructorElement constructor; | |
| 874 final Map<Element, AstConstant> definitions; | |
| 875 final Map<Element, AstConstant> fieldValues; | |
| 876 | |
| 877 /** | |
| 878 * Documentation wanted -- johnniwinther | |
| 879 * | |
| 880 * Invariant: [constructor] must be an implementation element. | |
| 881 */ | |
| 882 ConstructorEvaluator(InterfaceType this.constructedType, | |
| 883 FunctionElement constructor, | |
| 884 ConstantCompiler handler, | |
| 885 Compiler compiler) | |
| 886 : this.constructor = constructor, | |
| 887 this.definitions = new Map<Element, AstConstant>(), | |
| 888 this.fieldValues = new Map<Element, AstConstant>(), | |
| 889 super(handler, | |
| 890 compiler.resolver.resolveMethodElement(constructor.declaration), | |
| 891 compiler, | |
| 892 isConst: true) { | |
| 893 assert(invariant(constructor, constructor.isImplementation)); | |
| 894 } | |
| 895 | |
| 896 AstConstant visitSend(Send send) { | |
| 897 Element element = elements[send]; | |
| 898 if (Elements.isLocal(element)) { | |
| 899 AstConstant constant = definitions[element]; | |
| 900 if (constant == null) { | |
| 901 compiler.internalError(send, "Local variable without value."); | |
| 902 } | |
| 903 return constant; | |
| 904 } | |
| 905 return super.visitSend(send); | |
| 906 } | |
| 907 | |
| 908 void potentiallyCheckType(Node node, | |
| 909 TypedElement element, | |
| 910 AstConstant constant) { | |
| 911 if (compiler.enableTypeAssertions) { | |
| 912 DartType elementType = element.type.substByContext(constructedType); | |
| 913 DartType constantType = constant.value.computeType(compiler); | |
| 914 if (!constantSystem.isSubtype(compiler, constantType, elementType)) { | |
| 915 compiler.withCurrentElement(constant.element, () { | |
| 916 compiler.reportFatalError( | |
| 917 constant.node, MessageKind.NOT_ASSIGNABLE, | |
| 918 {'fromType': constantType, 'toType': elementType}); | |
| 919 }); | |
| 920 } | |
| 921 } | |
| 922 } | |
| 923 | |
| 924 void updateFieldValue(Node node, | |
| 925 TypedElement element, | |
| 926 AstConstant constant) { | |
| 927 potentiallyCheckType(node, element, constant); | |
| 928 fieldValues[element] = constant; | |
| 929 } | |
| 930 | |
| 931 /** | |
| 932 * Given the arguments (a list of constants) assigns them to the parameters, | |
| 933 * updating the definitions map. If the constructor has field-initializer | |
| 934 * parameters (like [:this.x:]), also updates the [fieldValues] map. | |
| 935 */ | |
| 936 void assignArgumentsToParameters(List<AstConstant> arguments) { | |
| 937 // Assign arguments to parameters. | |
| 938 FunctionSignature signature = constructor.functionSignature; | |
| 939 int index = 0; | |
| 940 signature.orderedForEachParameter((ParameterElement parameter) { | |
| 941 AstConstant argument = arguments[index++]; | |
| 942 Node node = parameter.node; | |
| 943 if (parameter.isInitializingFormal) { | |
| 944 InitializingFormalElement initializingFormal = parameter; | |
| 945 updateFieldValue(node, initializingFormal.fieldElement, argument); | |
| 946 } else { | |
| 947 potentiallyCheckType(node, parameter, argument); | |
| 948 definitions[parameter] = argument; | |
| 949 } | |
| 950 }); | |
| 951 } | |
| 952 | |
| 953 void evaluateSuperOrRedirectSend(List<AstConstant> compiledArguments, | |
| 954 FunctionElement targetConstructor) { | |
| 955 ConstructorEvaluator evaluator = new ConstructorEvaluator( | |
| 956 constructedType.asInstanceOf(targetConstructor.enclosingClass), | |
| 957 targetConstructor, handler, compiler); | |
| 958 evaluator.evaluateConstructorFieldValues(compiledArguments); | |
| 959 // Copy over the fieldValues from the super/redirect-constructor. | |
| 960 // No need to go through [updateFieldValue] because the | |
| 961 // assignments have already been checked in checked mode. | |
| 962 evaluator.fieldValues.forEach((key, value) => fieldValues[key] = value); | |
| 963 } | |
| 964 | |
| 965 /** | |
| 966 * Runs through the initializers of the given [constructor] and updates | |
| 967 * the [fieldValues] map. | |
| 968 */ | |
| 969 void evaluateConstructorInitializers() { | |
| 970 if (constructor.isSynthesized) { | |
| 971 List<AstConstant> compiledArguments = <AstConstant>[]; | |
| 972 | |
| 973 Function compileArgument = (element) => definitions[element]; | |
| 974 Function compileConstant = handler.compileConstant; | |
| 975 FunctionElement target = constructor.definingConstructor.implementation; | |
| 976 Selector.addForwardingElementArgumentsToList(constructor, | |
| 977 compiledArguments, | |
| 978 target, | |
| 979 compileArgument, | |
| 980 compileConstant, | |
| 981 compiler.world); | |
| 982 evaluateSuperOrRedirectSend(compiledArguments, target); | |
| 983 return; | |
| 984 } | |
| 985 FunctionExpression functionNode = constructor.node; | |
| 986 NodeList initializerList = functionNode.initializers; | |
| 987 | |
| 988 bool foundSuperOrRedirect = false; | |
| 989 | |
| 990 if (initializerList != null) { | |
| 991 for (Link<Node> link = initializerList.nodes; | |
| 992 !link.isEmpty; | |
| 993 link = link.tail) { | |
| 994 assert(link.head is Send); | |
| 995 if (link.head is !SendSet) { | |
| 996 // A super initializer or constructor redirection. | |
| 997 Send call = link.head; | |
| 998 FunctionElement target = elements[call]; | |
| 999 List<AstConstant> compiledArguments = | |
| 1000 evaluateArgumentsToConstructor( | |
| 1001 call, elements.getSelector(call), call.arguments, target, | |
| 1002 compileArgument: evaluateConstant); | |
| 1003 evaluateSuperOrRedirectSend(compiledArguments, target); | |
| 1004 foundSuperOrRedirect = true; | |
| 1005 } else { | |
| 1006 // A field initializer. | |
| 1007 SendSet init = link.head; | |
| 1008 Link<Node> initArguments = init.arguments; | |
| 1009 assert(!initArguments.isEmpty && initArguments.tail.isEmpty); | |
| 1010 AstConstant fieldValue = evaluate(initArguments.head); | |
| 1011 updateFieldValue(init, elements[init], fieldValue); | |
| 1012 } | |
| 1013 } | |
| 1014 } | |
| 1015 | |
| 1016 if (!foundSuperOrRedirect) { | |
| 1017 // No super initializer found. Try to find the default constructor if | |
| 1018 // the class is not Object. | |
| 1019 ClassElement enclosingClass = constructor.enclosingClass; | |
| 1020 ClassElement superClass = enclosingClass.superclass; | |
| 1021 if (enclosingClass != compiler.objectClass) { | |
| 1022 assert(superClass != null); | |
| 1023 assert(superClass.resolutionState == STATE_DONE); | |
| 1024 | |
| 1025 Selector selector = | |
| 1026 new Selector.callDefaultConstructor(enclosingClass.library); | |
| 1027 | |
| 1028 FunctionElement targetConstructor = | |
| 1029 superClass.lookupConstructor(selector); | |
| 1030 if (targetConstructor == null) { | |
| 1031 compiler.internalError(functionNode, | |
| 1032 "No default constructor available."); | |
| 1033 } | |
| 1034 List<AstConstant> compiledArguments = | |
| 1035 evaluateArgumentsToConstructor( | |
| 1036 functionNode, selector, const Link<Node>(), targetConstructor); | |
| 1037 evaluateSuperOrRedirectSend(compiledArguments, targetConstructor); | |
| 1038 } | |
| 1039 } | |
| 1040 } | |
| 1041 | |
| 1042 /** | |
| 1043 * Simulates the execution of the [constructor] with the given | |
| 1044 * [arguments] to obtain the field values that need to be passed to the | |
| 1045 * native JavaScript constructor. | |
| 1046 */ | |
| 1047 void evaluateConstructorFieldValues(List<AstConstant> arguments) { | |
| 1048 compiler.withCurrentElement(constructor, () { | |
| 1049 assignArgumentsToParameters(arguments); | |
| 1050 evaluateConstructorInitializers(); | |
| 1051 }); | |
| 1052 } | |
| 1053 | |
| 1054 /// Builds a normalized list of the constant values for each field in the | |
| 1055 /// inheritance chain of [classElement]. | |
| 1056 List<AstConstant> buildFieldConstants(ClassElement classElement) { | |
| 1057 List<AstConstant> fieldConstants = <AstConstant>[]; | |
| 1058 classElement.implementation.forEachInstanceField( | |
| 1059 (ClassElement enclosing, FieldElement field) { | |
| 1060 AstConstant fieldValue = fieldValues[field]; | |
| 1061 if (fieldValue == null) { | |
| 1062 // Use the default value. | |
| 1063 fieldValue = new AstConstant.fromDefaultValue( | |
| 1064 field, handler.compileConstant(field)); | |
| 1065 } | |
| 1066 fieldConstants.add(fieldValue); | |
| 1067 }, | |
| 1068 includeSuperAndInjectedMembers: true); | |
| 1069 return fieldConstants; | |
| 1070 } | |
| 1071 } | |
| 1072 | |
| 1073 /// A constant created from the front-end AST. | |
| 1074 /// | |
| 1075 /// [element] and [node] point to the source location of the constant. | |
| 1076 /// [expression] holds the symbolic constant expression and [value] its constant | |
| 1077 /// value. | |
| 1078 /// | |
| 1079 /// This class differs from [ConstantExpression] in that it is coupled to the | |
| 1080 /// front-end AST whereas [ConstantExpression] is only coupled to the element | |
| 1081 /// model. | |
| 1082 class AstConstant { | |
| 1083 final Element element; | |
| 1084 final Node node; | |
| 1085 final ConstantExpression expression; | |
| 1086 | |
| 1087 AstConstant(this.element, this.node, this.expression); | |
| 1088 | |
| 1089 factory AstConstant.fromDefaultValue( | |
| 1090 VariableElement element, | |
| 1091 ConstantExpression constant) { | |
| 1092 return new AstConstant( | |
| 1093 element, | |
| 1094 element.initializer != null ? element.initializer : element.node, | |
| 1095 constant); | |
| 1096 } | |
| 1097 | |
| 1098 ConstantValue get value => expression.value; | |
| 1099 | |
| 1100 String toString() => expression.toString(); | |
| 1101 } | |
| OLD | NEW |
|---|
Chromium Code Reviews
Issue 694353007:
Move dart2js from sdk/lib/_internal/compiler to pkg/compiler (Closed)
Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart