Linter Demo

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Warnings: 13

File: /home/fstrocco/Dart/dart/benchmark/compiler/lib/src/js_emitter/interceptor_stub_generator.dart

// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file // for details. All rights reserved. Use of this source code is governed by a // BSD-style license that can be found in the LICENSE file. part of dart2js.js_emitter; class InterceptorStubGenerator { final Compiler compiler; final Namer namer; final JavaScriptBackend backend; InterceptorStubGenerator(this.compiler, this.namer, this.backend); Emitter get emitter => backend.emitter.emitter; jsAst.Expression generateGetInterceptorMethod(Set<ClassElement> classes) { jsAst.Expression interceptorFor(ClassElement cls) { return backend.emitter.interceptorPrototypeAccess(cls); } /** * Build a JavaScrit AST node for doing a type check on * [cls]. [cls] must be a non-native interceptor class. */ jsAst.Statement buildInterceptorCheck(ClassElement cls) { jsAst.Expression condition; assert(backend.isInterceptorClass(cls)); if (cls == backend.jsBoolClass) { condition = js('(typeof receiver) == "boolean"'); } else if (cls == backend.jsIntClass || cls == backend.jsDoubleClass || cls == backend.jsNumberClass) { throw 'internal error'; } else if (cls == backend.jsArrayClass || cls == backend.jsMutableArrayClass || cls == backend.jsFixedArrayClass || cls == backend.jsExtendableArrayClass) { condition = js('receiver.constructor == Array'); } else if (cls == backend.jsStringClass) { condition = js('(typeof receiver) == "string"'); } else if (cls == backend.jsNullClass) { condition = js('receiver == null'); } else { throw 'internal error'; } return js.statement('if (#) return #', [condition, interceptorFor(cls)]); } bool hasArray = false; bool hasBool = false; bool hasDouble = false; bool hasInt = false; bool hasNull = false; bool hasNumber = false; bool hasString = false; bool hasNative = false; bool anyNativeClasses = compiler.enqueuer.codegen.nativeEnqueuer .hasInstantiatedNativeClasses(); for (ClassElement cls in classes) { if (cls == backend.jsArrayClass || cls == backend.jsMutableArrayClass || cls == backend.jsFixedArrayClass || cls == backend.jsExtendableArrayClass) hasArray = true; else if (cls == backend.jsBoolClass) hasBool = true; else if (cls == backend.jsDoubleClass) hasDouble = true; else if (cls == backend.jsIntClass) hasInt = true; else if (cls == backend.jsNullClass) hasNull = true; else if (cls == backend.jsNumberClass) hasNumber = true; else if (cls == backend.jsStringClass) hasString = true; else { // The set of classes includes classes mixed-in to interceptor classes // and user extensions of native classes. // // The set of classes also includes the 'primitive' interceptor // PlainJavaScriptObject even when it has not been resolved, since it is // only resolved through the reference in getNativeInterceptor when // getNativeInterceptor is marked as used. Guard against probing // unresolved PlainJavaScriptObject by testing for anyNativeClasses. if (anyNativeClasses) { if (Elements.isNativeOrExtendsNative(cls)) hasNative = true; } } } if (hasDouble) { hasNumber = true; } if (hasInt) hasNumber = true; if (classes.containsAll(backend.interceptedClasses)) { // I.e. this is the general interceptor. hasNative = anyNativeClasses; } List<jsAst.Statement> statements = <jsAst.Statement>[]; if (hasNumber) { jsAst.Statement whenNumber; /// Note: there are two number classes in play: Dart's [num], /// and JavaScript's Number (typeof receiver == 'number'). This /// is the fallback used when we have determined that receiver /// is a JavaScript Number. jsAst.Expression interceptorForNumber = interceptorFor( hasDouble ? backend.jsDoubleClass : backend.jsNumberClass); if (hasInt) { whenNumber = js.statement('''{ if (Math.floor(receiver) == receiver) return #; return #; }''', [interceptorFor(backend.jsIntClass), interceptorForNumber]); } else { whenNumber = js.statement('return #', interceptorForNumber); } statements.add( js.statement('if (typeof receiver == "number") #;', whenNumber)); } if (hasString) { statements.add(buildInterceptorCheck(backend.jsStringClass)); } if (hasNull) { statements.add(buildInterceptorCheck(backend.jsNullClass)); } else { // Returning "undefined" or "null" here will provoke a JavaScript // TypeError which is later identified as a null-error by // [unwrapException] in js_helper.dart. statements.add( js.statement('if (receiver == null) return receiver')); } if (hasBool) { statements.add(buildInterceptorCheck(backend.jsBoolClass)); } // TODO(ahe): It might be faster to check for Array before // function and bool. if (hasArray) { statements.add(buildInterceptorCheck(backend.jsArrayClass)); } if (hasNative) { statements.add(js.statement(r'''{ if (typeof receiver != "object") return receiver; if (receiver instanceof #) return receiver; return #(receiver); }''', [ backend.emitter.constructorAccess(compiler.objectClass), backend.emitter .staticFunctionAccess(backend.getNativeInterceptorMethod)])); } else { ClassElement jsUnknown = backend.jsUnknownJavaScriptObjectClass; if (compiler.codegenWorld .directlyInstantiatedClasses.contains(jsUnknown)) { statements.add( js.statement('if (!(receiver instanceof #)) return #;', [backend.emitter.constructorAccess(compiler.objectClass), interceptorFor(jsUnknown)])); } statements.add(js.statement('return receiver')); } return js('''function(receiver) { #; }''', new jsAst.Block(statements)); } // Returns a statement that takes care of performance critical // common case for a one-shot interceptor, or null if there is no // fast path. jsAst.Statement _fastPathForOneShotInterceptor(Selector selector, Set<ClassElement> classes) { if (selector.isOperator) { String name = selector.name; if (name == '==') { return js.statement('''{ if (receiver == null) return a0 == null; if (typeof receiver != "object") return a0 != null && receiver === a0; }'''); } if (!classes.contains(backend.jsIntClass) && !classes.contains(backend.jsNumberClass) && !classes.contains(backend.jsDoubleClass)) { return null; } if (selector.argumentCount == 1) { // The following operators do not map to a JavaScript operator. if (name == '~/' || name == '<<' || name == '%' || name == '>>') { return null; } jsAst.Expression result = js('receiver $name a0'); if (name == '&' || name == '|' || name == '^') { result = js('# >>> 0', result); } return js.statement( 'if (typeof receiver == "number" && typeof a0 == "number")' ' return #;', result); } else if (name == 'unary-') { return js.statement( 'if (typeof receiver == "number") return -receiver'); } else { assert(name == '~'); return js.statement(''' if (typeof receiver == "number" && Math.floor(receiver) == receiver) return (~receiver) >>> 0; '''); } } else if (selector.isIndex || selector.isIndexSet) { // For an index operation, this code generates: // // if (receiver.constructor == Array || typeof receiver == "string") { // if (a0 >>> 0 === a0 && a0 < receiver.length) { // return receiver[a0]; // } // } // // For an index set operation, this code generates: // // if (receiver.constructor == Array && !receiver.immutable$list) { // if (a0 >>> 0 === a0 && a0 < receiver.length) { // return receiver[a0] = a1; // } // } bool containsArray = classes.contains(backend.jsArrayClass); bool containsString = classes.contains(backend.jsStringClass); bool containsJsIndexable = backend.jsIndexingBehaviorInterface.isResolved && classes.any((cls) { return compiler.world.isSubtypeOf(cls, backend.jsIndexingBehaviorInterface); }); // The index set operator requires a check on its set value in // checked mode, so we don't optimize the interceptor if the // compiler has type assertions enabled. if (selector.isIndexSet && (compiler.enableTypeAssertions || !containsArray)) { return null; } if (!containsArray && !containsString) { return null; } jsAst.Expression arrayCheck = js('receiver.constructor == Array'); jsAst.Expression indexableCheck = backend.generateIsJsIndexableCall(js('receiver'), js('receiver')); jsAst.Expression orExp(left, right) { return left == null ? right : js('# || #', [left, right]); } if (selector.isIndex) { jsAst.Expression typeCheck; if (containsArray) { typeCheck = arrayCheck; } if (containsString) { typeCheck = orExp(typeCheck, js('typeof receiver == "string"')); } if (containsJsIndexable) { typeCheck = orExp(typeCheck, indexableCheck); } return js.statement(''' if (#) if ((a0 >>> 0) === a0 && a0 < receiver.length) return receiver[a0]; ''', typeCheck); } else { jsAst.Expression typeCheck; if (containsArray) { typeCheck = arrayCheck; } if (containsJsIndexable) { typeCheck = orExp(typeCheck, indexableCheck); } return js.statement(r''' if (# && !receiver.immutable$list && (a0 >>> 0) === a0 && a0 < receiver.length) return receiver[a0] = a1; ''', typeCheck); } } return null; } jsAst.Expression generateOneShotInterceptor(String name) { Selector selector = backend.oneShotInterceptors[name]; Set<ClassElement> classes = backend.getInterceptedClassesOn(selector.name); String getInterceptorName = namer.nameForGetInterceptor(classes); List<String> parameterNames = <String>[]; parameterNames.add('receiver'); if (selector.isSetter) { parameterNames.add('value'); } else { for (int i = 0; i < selector.argumentCount; i++) { parameterNames.add('a$i'); } } String invocationName = backend.namer.invocationName(selector); String globalObject = namer.globalObjectFor(backend.interceptorsLibrary); jsAst.Statement optimizedPath = _fastPathForOneShotInterceptor(selector, classes); if (optimizedPath == null) optimizedPath = js.statement(';'); return js( 'function(#) { #; return #.#(receiver).#(#) }', [parameterNames, optimizedPath, globalObject, getInterceptorName, invocationName, parameterNames]); } jsAst.ArrayInitializer generateTypeToInterceptorMap() { // TODO(sra): Perhaps inject a constant instead? CustomElementsAnalysis analysis = backend.customElementsAnalysis; if (!analysis.needsTable) return null; List<jsAst.Expression> elements = <jsAst.Expression>[]; JavaScriptConstantCompiler handler = backend.constants; List<ConstantValue> constants = handler.getConstantsForEmission(emitter.compareConstants); for (ConstantValue constant in constants) { if (constant is TypeConstantValue) { TypeConstantValue typeConstant = constant; Element element = typeConstant.representedType.element; if (element is ClassElement) { ClassElement classElement = element; if (!analysis.needsClass(classElement)) continue; elements.add(emitter.constantReference(constant)); elements.add(backend.emitter.interceptorClassAccess(classElement)); // Create JavaScript Object map for by-name lookup of generative // constructors. For example, the class A has three generative // constructors // // class A { // A() {} // A.foo() {} // A.bar() {} // } // // Which are described by the map // // {"": A.A$, "foo": A.A$foo, "bar": A.A$bar} // // We expect most of the time the map will be a singleton. var properties = []; for (Element member in analysis.constructors(classElement)) { properties.add( new jsAst.Property( js.string(member.name), backend.emitter.staticFunctionAccess(member))); } var map = new jsAst.ObjectInitializer(properties); elements.add(map); } } } return new jsAst.ArrayInitializer(elements); } }