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1 // Copyright (c) 2013, 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 js_backend; | |
6 | |
7 /** | |
8 * Handles construction of TypeVariable constants needed at runtime. | |
9 */ | |
10 class TypeVariableHandler { | |
11 JavaScriptBackend backend; | |
12 FunctionElement typeVariableConstructor; | |
13 CompileTimeConstantEvaluator evaluator; | |
14 | |
15 /** | |
16 * Contains all instantiated classes that have type variables and are needed | |
17 * for reflection. | |
18 */ | |
19 List<ClassElement> typeVariableClasses = new List<ClassElement>(); | |
20 | |
21 /** | |
22 * Maps a class element to a list with indices that point to type variables | |
23 * constants for each of the class' type variables. | |
24 */ | |
25 Map<ClassElement, List<int>> typeVariables = | |
26 new Map<ClassElement, List<int>>(); | |
27 | |
28 /** | |
29 * Maps a TypeVariableType to the index pointing to the constant representing | |
30 * the corresponding type variable at runtime. | |
31 */ | |
32 Map<TypeVariableElement, int> typeVariableConstants = | |
33 new Map<TypeVariableElement, int>(); | |
34 | |
35 TypeVariableHandler(this.backend); | |
36 | |
37 ClassElement get typeVariableClass => backend.typeVariableClass; | |
38 CodeEmitterTask get task => backend.emitter; | |
39 MetadataEmitter get emitter => task.oldEmitter.metadataEmitter; | |
40 Compiler get compiler => backend.compiler; | |
41 | |
42 void registerClassWithTypeVariables(ClassElement cls) { | |
43 if (typeVariableClasses != null) { | |
44 typeVariableClasses.add(cls); | |
45 } | |
46 } | |
47 | |
48 void processTypeVariablesOf(ClassElement cls) { | |
49 //TODO(zarah): Running through all the members is suboptimal. Change this | |
50 // as part of marking elements for reflection. | |
51 bool hasMemberNeededForReflection(ClassElement cls) { | |
52 bool result = false; | |
53 cls.implementation.forEachMember((ClassElement cls, Element member) { | |
54 result = result || backend.referencedFromMirrorSystem(member); | |
55 }); | |
56 return result; | |
57 } | |
58 | |
59 if (!backend.referencedFromMirrorSystem(cls) && | |
60 !hasMemberNeededForReflection(cls)) { | |
61 return; | |
62 } | |
63 | |
64 InterfaceType typeVariableType = typeVariableClass.thisType; | |
65 List<int> constants = <int>[]; | |
66 | |
67 for (TypeVariableType currentTypeVariable in cls.typeVariables) { | |
68 TypeVariableElement typeVariableElement = currentTypeVariable.element; | |
69 | |
70 AstConstant wrapConstant(ConstantExpression constant) { | |
71 return new AstConstant(typeVariableElement, | |
72 typeVariableElement.node, | |
73 constant); | |
74 } | |
75 | |
76 ConstantExpression name = new PrimitiveConstantExpression( | |
77 backend.constantSystem.createString( | |
78 new DartString.literal(currentTypeVariable.name))); | |
79 ConstantExpression bound = new PrimitiveConstantExpression( | |
80 backend.constantSystem.createInt( | |
81 emitter.reifyType(typeVariableElement.bound))); | |
82 ConstantExpression type = backend.constants.createTypeConstant(cls); | |
83 List<AstConstant> arguments = | |
84 [wrapConstant(type), wrapConstant(name), wrapConstant(bound)]; | |
85 | |
86 // TODO(johnniwinther): Support a less front-end specific creation of | |
87 // constructed constants. | |
88 AstConstant constant = | |
89 CompileTimeConstantEvaluator.makeConstructedConstant( | |
90 compiler, | |
91 backend.constants, | |
92 typeVariableElement, | |
93 typeVariableElement.node, | |
94 typeVariableType, | |
95 typeVariableConstructor, | |
96 new Selector.callConstructor('', null, 3), | |
97 arguments, | |
98 arguments); | |
99 ConstantValue value = constant.value; | |
100 backend.registerCompileTimeConstant(value, compiler.globalDependencies); | |
101 backend.constants.addCompileTimeConstantForEmission(value); | |
102 constants.add( | |
103 reifyTypeVariableConstant(value, currentTypeVariable.element)); | |
104 } | |
105 typeVariables[cls] = constants; | |
106 } | |
107 | |
108 void onTreeShakingDisabled(Enqueuer enqueuer) { | |
109 if (enqueuer.isResolutionQueue) { | |
110 backend.enqueueClass( | |
111 enqueuer, typeVariableClass, compiler.globalDependencies); | |
112 typeVariableClass.ensureResolved(compiler); | |
113 Link constructors = typeVariableClass.constructors; | |
114 if (constructors.isEmpty && constructors.tail.isEmpty) { | |
115 compiler.internalError(typeVariableClass, | |
116 "Class '$typeVariableClass' should only have one constructor"); | |
117 } | |
118 typeVariableConstructor = typeVariableClass.constructors.head; | |
119 backend.enqueueInResolution(typeVariableConstructor, | |
120 compiler.globalDependencies); | |
121 enqueuer.registerInstantiatedType(typeVariableClass.rawType, | |
122 compiler.globalDependencies); | |
123 enqueuer.registerStaticUse(backend.getCreateRuntimeType()); | |
124 } else if (typeVariableClasses != null) { | |
125 List<ClassElement> worklist = typeVariableClasses; | |
126 typeVariableClasses = null; | |
127 worklist.forEach((cls) => processTypeVariablesOf(cls)); | |
128 } | |
129 } | |
130 | |
131 /** | |
132 * Adds [c] to [emitter.globalMetadata] and returns the index pointing to | |
133 * the entry. | |
134 * | |
135 * If the corresponding type variable has already been encountered an | |
136 * entry in the list has already been reserved and the constant is added | |
137 * there, otherwise a new entry for [c] is created. | |
138 */ | |
139 int reifyTypeVariableConstant(ConstantValue c, TypeVariableElement variable) { | |
140 String name = jsAst.prettyPrint(task.constantReference(c), | |
141 compiler).getText(); | |
142 int index; | |
143 if (typeVariableConstants.containsKey(variable)) { | |
144 index = typeVariableConstants[variable]; | |
145 emitter.globalMetadata[index] = name; | |
146 } else { | |
147 index = emitter.addGlobalMetadata(name); | |
148 typeVariableConstants[variable] = index; | |
149 } | |
150 return index; | |
151 } | |
152 | |
153 /** | |
154 * Returns the index pointing to the constant in [emitter.globalMetadata] | |
155 * representing this type variable. | |
156 * | |
157 * If the constant has not yet been constructed, an entry is allocated in | |
158 * the global metadata list and the index pointing to this entry is returned. | |
159 * When the corresponding constant is constructed later, | |
160 * [reifyTypeVariableConstant] will be called and the constant will be added | |
161 * on the allocated entry. | |
162 */ | |
163 int reifyTypeVariable(TypeVariableElement variable) { | |
164 if (typeVariableConstants.containsKey(variable)) { | |
165 return typeVariableConstants[variable]; | |
166 } | |
167 | |
168 // TODO(15613): Remove quotes. | |
169 emitter.globalMetadata.add('"Placeholder for ${variable}"'); | |
170 return typeVariableConstants[variable] = emitter.globalMetadata.length - 1; | |
171 } | |
172 | |
173 List<int> typeVariablesOf(ClassElement classElement) { | |
174 List<int> result = typeVariables[classElement]; | |
175 if (result == null) { | |
176 result = const <int>[]; | |
177 } | |
178 return result; | |
179 } | |
180 } | |
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