| library dart2js.unsugar_cps; |
| |
| import '../../cps_ir/cps_ir_nodes.dart'; |
| |
| import '../../cps_ir/optimizers.dart' show ParentVisitor, Pass; |
| import '../../constants/values.dart'; |
| import '../../elements/elements.dart'; |
| import '../../io/source_information.dart'; |
| import '../../js_backend/codegen/glue.dart'; |
| import '../../universe/selector.dart' show Selector; |
| import '../../cps_ir/cps_ir_builder.dart' show ThisParameterLocal; |
| |
| class ExplicitReceiverParameterEntity implements Local { |
| String get name => 'receiver'; |
| final ExecutableElement executableContext; |
| ExplicitReceiverParameterEntity(this.executableContext); |
| toString() => 'ExplicitReceiverParameterEntity($executableContext)'; |
| } |
| |
| /// Suggested name for an interceptor. |
| class InterceptorEntity extends Entity { |
| Entity interceptedVariable; |
| |
| InterceptorEntity(this.interceptedVariable); |
| |
| String get name => interceptedVariable.name + '_'; |
| } |
| |
| |
| /// Rewrites the initial CPS IR to make Dart semantics explicit and inserts |
| /// special nodes that respect JavaScript behavior. |
| /// |
| /// Performs the following rewrites: |
| /// - Add interceptors at call sites that use interceptor calling convention. |
| /// - Add explicit receiver argument for methods that are called in interceptor |
| /// calling convention. |
| /// - Convert two-parameter exception handlers to one-parameter ones. |
| class UnsugarVisitor extends RecursiveVisitor implements Pass { |
| Glue _glue; |
| ParentVisitor _parentVisitor = new ParentVisitor(); |
| |
| Parameter thisParameter; |
| Parameter explicitReceiverParameter; |
| |
| // In a catch block, rethrow implicitly throws the block's exception |
| // parameter. This is the exception parameter when nested in a catch |
| // block and null otherwise. |
| Parameter _exceptionParameter = null; |
| |
| UnsugarVisitor(this._glue); |
| |
| String get passName => 'Unsugaring'; |
| |
| bool methodUsesReceiverArgument(FunctionElement function) { |
| assert(_glue.isInterceptedMethod(function)); |
| ClassElement clazz = function.enclosingClass.declaration; |
| return _glue.isInterceptorClass(clazz) || |
| _glue.isUsedAsMixin(clazz); |
| } |
| |
| void rewrite(FunctionDefinition function) { |
| thisParameter = function.thisParameter; |
| bool inInterceptedMethod = _glue.isInterceptedMethod(function.element); |
| |
| if (function.element.name == '==' && |
| function.parameters.length == 1 && |
| !_glue.operatorEqHandlesNullArgument(function.element)) { |
| // Insert the null check that the language semantics requires us to |
| // perform before calling operator ==. |
| insertEqNullCheck(function); |
| } |
| |
| if (inInterceptedMethod) { |
| ThisParameterLocal holder = thisParameter.hint; |
| explicitReceiverParameter = new Parameter( |
| new ExplicitReceiverParameterEntity( |
| holder.executableContext)); |
| function.parameters.insert(0, explicitReceiverParameter); |
| } |
| |
| // Set all parent pointers. |
| _parentVisitor.visit(function); |
| |
| if (inInterceptedMethod && methodUsesReceiverArgument(function.element)) { |
| explicitReceiverParameter.substituteFor(thisParameter); |
| } |
| |
| visit(function); |
| } |
| |
| Constant get trueConstant { |
| return new Constant(new TrueConstantValue()); |
| } |
| |
| Constant get falseConstant { |
| return new Constant(new FalseConstantValue()); |
| } |
| |
| Constant get nullConstant { |
| return new Constant(new NullConstantValue()); |
| } |
| |
| void insertLetPrim(Primitive primitive, Expression node) { |
| LetPrim let = new LetPrim(primitive); |
| InteriorNode parent = node.parent; |
| parent.body = let; |
| let.body = node; |
| node.parent = let; |
| let.parent = parent; |
| } |
| |
| void insertEqNullCheck(FunctionDefinition function) { |
| // Replace |
| // |
| // body; |
| // |
| // with |
| // |
| // if (identical(arg, null)) |
| // return false; |
| // else |
| // body; |
| // |
| Continuation originalBody = new Continuation(<Parameter>[]); |
| originalBody.body = function.body; |
| |
| Continuation returnFalse = new Continuation(<Parameter>[]); |
| Primitive falsePrimitive = falseConstant; |
| returnFalse.body = |
| new LetPrim(falsePrimitive, |
| new InvokeContinuation( |
| function.returnContinuation, <Primitive>[falsePrimitive])); |
| |
| Primitive nullPrimitive = nullConstant; |
| Primitive test = new ApplyBuiltinOperator( |
| BuiltinOperator.Identical, |
| <Primitive>[function.parameters.single, nullPrimitive], |
| function.parameters.single.sourceInformation); |
| |
| Expression newBody = |
| new LetCont.many(<Continuation>[returnFalse, originalBody], |
| new LetPrim(nullPrimitive, |
| new LetPrim(test, |
| new Branch.loose(test, returnFalse, originalBody)))); |
| function.body = newBody; |
| } |
| |
| /// Insert a static call to [function] at the point of [node] with result |
| /// [result]. |
| /// |
| /// Rewrite [node] to |
| /// |
| /// let cont continuation(result) = node |
| /// in invoke function arguments continuation |
| void insertStaticCall(FunctionElement function, List<Primitive> arguments, |
| Parameter result, |
| Expression node) { |
| InteriorNode parent = node.parent; |
| Continuation continuation = new Continuation([result]); |
| continuation.body = node; |
| _parentVisitor.processContinuation(continuation); |
| |
| Selector selector = new Selector.fromElement(function); |
| // TODO(johnniwinther): Come up with an implementation of SourceInformation |
| // for calls such as this one that don't appear in the original source. |
| InvokeStatic invoke = new InvokeStatic( |
| function, selector, arguments, continuation, null); |
| _parentVisitor.processInvokeStatic(invoke); |
| |
| LetCont letCont = new LetCont(continuation, invoke); |
| _parentVisitor.processLetCont(letCont); |
| |
| parent.body = letCont; |
| letCont.parent = parent; |
| } |
| |
| @override |
| Expression traverseLetHandler(LetHandler node) { |
| assert(node.handler.parameters.length == 2); |
| Parameter previousExceptionParameter = _exceptionParameter; |
| |
| // BEFORE: Handlers have two parameters, exception and stack trace. |
| // AFTER: Handlers have a single parameter, which is unwrapped to get |
| // the exception and stack trace. |
| _exceptionParameter = node.handler.parameters.first; |
| Parameter stackTraceParameter = node.handler.parameters.last; |
| Expression body = node.handler.body; |
| if (_exceptionParameter.hasAtLeastOneUse || |
| stackTraceParameter.hasAtLeastOneUse) { |
| Parameter exceptionValue = new Parameter(null); |
| exceptionValue.substituteFor(_exceptionParameter); |
| insertStaticCall(_glue.getExceptionUnwrapper(), [_exceptionParameter], |
| exceptionValue, body); |
| |
| if (stackTraceParameter.hasAtLeastOneUse) { |
| Parameter stackTraceValue = new Parameter(null); |
| stackTraceValue.substituteFor(stackTraceParameter); |
| insertStaticCall(_glue.getTraceFromException(), [_exceptionParameter], |
| stackTraceValue, body); |
| } |
| } |
| |
| assert(stackTraceParameter.hasNoUses); |
| node.handler.parameters.removeLast(); |
| |
| visit(node.handler); |
| _exceptionParameter = previousExceptionParameter; |
| |
| return node.body; |
| } |
| |
| processThrow(Throw node) { |
| // The subexpression of throw is wrapped in the JavaScript output. |
| Parameter value = new Parameter(null); |
| insertStaticCall(_glue.getWrapExceptionHelper(), [node.value.definition], |
| value, node); |
| node.value.unlink(); |
| node.value = new Reference<Primitive>(value); |
| } |
| |
| processRethrow(Rethrow node) { |
| // Rethrow can only appear in a catch block. It throws that block's |
| // (wrapped) caught exception. |
| Throw replacement = new Throw(_exceptionParameter); |
| InteriorNode parent = node.parent; |
| parent.body = replacement; |
| replacement.parent = parent; |
| // The original rethrow does not have any references that we need to |
| // worry about unlinking. |
| } |
| |
| processInvokeMethod(InvokeMethod node) { |
| Selector selector = node.selector; |
| if (!_glue.isInterceptedSelector(selector)) return; |
| |
| Primitive receiver = node.receiver.definition; |
| Primitive newReceiver; |
| |
| if (receiver == explicitReceiverParameter) { |
| // If the receiver is the explicit receiver, we are calling a method in |
| // the same interceptor: |
| // Change 'receiver.foo()' to 'this.foo(receiver)'. |
| newReceiver = thisParameter; |
| } else { |
| LetCont contBinding = node.parent; |
| newReceiver = new Interceptor(receiver, node.sourceInformation) |
| ..interceptedClasses.addAll(_glue.getInterceptedClassesOn(selector)); |
| if (receiver.hint != null) { |
| newReceiver.hint = new InterceptorEntity(receiver.hint); |
| } |
| insertLetPrim(newReceiver, contBinding); |
| } |
| node.arguments.insert(0, node.receiver); |
| node.receiver = new Reference<Primitive>(newReceiver); |
| node.receiverIsIntercepted = true; |
| } |
| |
| processInvokeMethodDirectly(InvokeMethodDirectly node) { |
| if (!_glue.isInterceptedMethod(node.target)) return; |
| |
| Selector selector = node.selector; |
| Primitive receiver = node.receiver.definition; |
| Primitive newReceiver; |
| |
| if (receiver == explicitReceiverParameter) { |
| // If the receiver is the explicit receiver, we are calling a method in |
| // the same interceptor: |
| // Change 'receiver.foo()' to 'this.foo(receiver)'. |
| newReceiver = thisParameter; |
| } else { |
| LetCont contBinding = node.parent; |
| newReceiver = new Interceptor(receiver, node.sourceInformation) |
| ..interceptedClasses.addAll(_glue.getInterceptedClassesOn(selector)); |
| if (receiver.hint != null) { |
| newReceiver.hint = new InterceptorEntity(receiver.hint); |
| } |
| insertLetPrim(newReceiver, contBinding); |
| } |
| node.arguments.insert(0, node.receiver); |
| node.receiver = new Reference<Primitive>(newReceiver); |
| } |
| |
| processInterceptor(Interceptor node) { |
| _glue.registerSpecializedGetInterceptor(node.interceptedClasses); |
| } |
| } |