Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

sdk/lib/_internal/compiler/implementation/js_backend/constant_emitter.dart

-// Copyright (c) 2012, 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 js_backend;
-
-class ConstantEmitter {
-  ConstantReferenceEmitter _referenceEmitter;
-  ConstantLiteralEmitter _literalEmitter;
-
-  ConstantEmitter(Compiler compiler,
-                  Namer namer,
-                  jsAst.Template makeConstantListTemplate) {
-    _literalEmitter = new ConstantLiteralEmitter(
-        compiler, namer, makeConstantListTemplate, this);
-    _referenceEmitter = new ConstantReferenceEmitter(compiler, namer, this);
-  }
-
-  /**
-   * Constructs an expression that is a reference to the constant.  Uses a
-   * canonical name unless the constant can be emitted multiple times (as for
-   * numbers and strings).
-   */
-  jsAst.Expression reference(ConstantValue constant) {
-    return _referenceEmitter.generate(constant);
-  }
-
-  /**
-   * Constructs a literal expression that evaluates to the constant. Uses a
-   * canonical name unless the constant can be emitted multiple times (as for
-   * numbers and strings).
-   */
-  jsAst.Expression literal(ConstantValue constant) {
-    return _literalEmitter.generate(constant);
-  }
-
-  /**
-   * Constructs an expression like [reference], but the expression is valid
-   * during isolate initialization.
-   */
-  jsAst.Expression referenceInInitializationContext(ConstantValue constant) {
-    return _referenceEmitter.generate(constant);
-  }
-
-  /**
-   * Constructs an expression used to initialize a canonicalized constant.
-   */
-  jsAst.Expression initializationExpression(ConstantValue constant) {
-    return _literalEmitter.generate(constant);
-  }
-}
-
-/**
- * Visitor for generating JavaScript expressions to refer to [ConstantValue]s.
- * Do not use directly, use methods from [ConstantEmitter].
- */
-class ConstantReferenceEmitter
-    implements ConstantValueVisitor<jsAst.Expression> {
-  final Compiler compiler;
-  final Namer namer;
-
-  final ConstantEmitter constantEmitter;
-
-  ConstantReferenceEmitter(this.compiler, this.namer, this.constantEmitter);
-
-  jsAst.Expression generate(ConstantValue constant) {
-    return _visit(constant);
-  }
-
-  jsAst.Expression _visit(ConstantValue constant) {
-    return constant.accept(this);
-  }
-
-  jsAst.Expression emitCanonicalVersion(ConstantValue constant) {
-    String name = namer.constantName(constant);
-    return new jsAst.PropertyAccess.field(
-        new jsAst.VariableUse(namer.globalObjectForConstant(constant)), name);
-  }
-
-  jsAst.Expression literal(ConstantValue constant) {
-      return constantEmitter.literal(constant);
-  }
-
-  jsAst.Expression visitFunction(FunctionConstantValue constant) {
-    return namer.isolateStaticClosureAccess(constant.element);
-  }
-
-  jsAst.Expression visitNull(NullConstantValue constant) {
-    return literal(constant);
-  }
-
-  jsAst.Expression visitInt(IntConstantValue constant) {
-    return literal(constant);
-  }
-
-  jsAst.Expression visitDouble(DoubleConstantValue constant) {
-    return literal(constant);
-  }
-
-  jsAst.Expression visitTrue(TrueConstantValue constant) {
-    return literal(constant);
-  }
-
-  jsAst.Expression visitFalse(FalseConstantValue constant) {
-    return literal(constant);
-  }
-
-  /**
-   * Write the contents of the quoted string to a [CodeBuffer] in
-   * a form that is valid as JavaScript string literal content.
-   * The string is assumed quoted by double quote characters.
-   */
-  jsAst.Expression visitString(StringConstantValue constant) {
-    // TODO(sra): If the string is long *and repeated* (and not on a hot path)
-    // then it should be assigned to a name.  We don't have reference counts (or
-    // profile information) here, so this is the wrong place.
-    return literal(constant);
-  }
-
-  jsAst.Expression visitList(ListConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-
-  jsAst.Expression visitMap(MapConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-
-  jsAst.Expression visitType(TypeConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-
-  jsAst.Expression visitConstructed(ConstructedConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-
-  jsAst.Expression visitInterceptor(InterceptorConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-
-  jsAst.Expression visitDummy(DummyConstantValue constant) {
-    return literal(constant);
-  }
-
-  jsAst.Expression visitDeferred(DeferredConstantValue constant) {
-    return emitCanonicalVersion(constant);
-  }
-}
-
-/**
- * Visitor for generating JavaScript expressions that litterally represent
- * [ConstantValue]s. These can be used for inlining constants or in
- * initializers. Do not use directly, use methods from [ConstantEmitter].
- */
-class ConstantLiteralEmitter implements ConstantValueVisitor<jsAst.Expression> {
-
-  // Matches blank lines, comment lines and trailing comments that can't be part
-  // of a string.
-  static final RegExp COMMENT_RE =
-      new RegExp(r'''^ *(//.*)?\n|  *//[^''"\n]*$''' , multiLine: true);
-
-  final Compiler compiler;
-  final Namer namer;
-  final jsAst.Template makeConstantListTemplate;
-  final ConstantEmitter constantEmitter;
-
-  ConstantLiteralEmitter(this.compiler,
-                         this.namer,
-                         this.makeConstantListTemplate,
-                         this.constantEmitter);
-
-  jsAst.Expression generate(ConstantValue constant) {
-    return _visit(constant);
-  }
-
-  jsAst.Expression _visit(ConstantValue constant) {
-    return constant.accept(this);
-  }
-
-  jsAst.Expression visitFunction(FunctionConstantValue constant) {
-    compiler.internalError(NO_LOCATION_SPANNABLE,
-        "The function constant does not need specific JS code.");
-    return null;
-  }
-
-  jsAst.Expression visitNull(NullConstantValue constant) {
-    return new jsAst.LiteralNull();
-  }
-
-  jsAst.Expression visitInt(IntConstantValue constant) {
-    return new jsAst.LiteralNumber('${constant.primitiveValue}');
-  }
-
-  jsAst.Expression visitDouble(DoubleConstantValue constant) {
-    double value = constant.primitiveValue;
-    if (value.isNaN) {
-      return js("0/0");
-    } else if (value == double.INFINITY) {
-      return js("1/0");
-    } else if (value == -double.INFINITY) {
-      return js("-1/0");
-    } else {
-      return new jsAst.LiteralNumber("$value");
-    }
-  }
-
-  jsAst.Expression visitTrue(TrueConstantValue constant) {
-    if (compiler.enableMinification) {
-      // Use !0 for true.
-      return js("!0");
-    } else {
-      return js('true');
-    }
-  }
-
-  jsAst.Expression visitFalse(FalseConstantValue constant) {
-    if (compiler.enableMinification) {
-      // Use !1 for false.
-      return js("!1");
-    } else {
-      return js('false');
-    }
-  }
-
-  /**
-   * Write the contents of the quoted string to a [CodeBuffer] in
-   * a form that is valid as JavaScript string literal content.
-   * The string is assumed quoted by double quote characters.
-   */
-  jsAst.Expression visitString(StringConstantValue constant) {
-    StringBuffer sb = new StringBuffer();
-    writeJsonEscapedCharsOn(constant.primitiveValue.slowToString(), sb);
-    return new jsAst.LiteralString('"$sb"');
-  }
-
-  jsAst.Expression visitList(ListConstantValue constant) {
-    List<jsAst.Expression> elements = _array(constant.entries);
-    jsAst.ArrayInitializer array = new jsAst.ArrayInitializer.from(elements);
-    jsAst.Expression value = makeConstantListTemplate.instantiate([array]);
-    return maybeAddTypeArguments(constant.type, value);
-  }
-
-  jsAst.Expression getJsConstructor(ClassElement element) {
-    return namer.elementAccess(element);
-  }
-
-  jsAst.Expression visitMap(JavaScriptMapConstant constant) {
-    jsAst.Expression jsMap() {
-      List<jsAst.Property> properties = <jsAst.Property>[];
-      for (int i = 0; i < constant.length; i++) {
-        StringConstantValue key = constant.keys[i];
-        if (key.primitiveValue == JavaScriptMapConstant.PROTO_PROPERTY) {
-          continue;
-        }
-
-        // Keys in literal maps must be emitted in place.
-        jsAst.Literal keyExpression = _visit(key);
-        jsAst.Expression valueExpression =
-            constantEmitter.reference(constant.values[i]);
-        properties.add(new jsAst.Property(keyExpression, valueExpression));
-      }
-      return new jsAst.ObjectInitializer(properties);
-    }
-
-    jsAst.Expression jsGeneralMap() {
-      List<jsAst.Expression> data = <jsAst.Expression>[];
-      for (int i = 0; i < constant.keys.length; i++) {
-        jsAst.Expression keyExpression =
-            constantEmitter.reference(constant.keys[i]);
-        jsAst.Expression valueExpression =
-            constantEmitter.reference(constant.values[i]);
-        data.add(keyExpression);
-        data.add(valueExpression);
-      }
-      return new jsAst.ArrayInitializer.from(data);
-    }
-
-    ClassElement classElement = constant.type.element;
-    String className = classElement.name;
-
-    List<jsAst.Expression> arguments = <jsAst.Expression>[];
-
-    // The arguments of the JavaScript constructor for any given Dart class
-    // are in the same order as the members of the class element.
-    int emittedArgumentCount = 0;
-    classElement.implementation.forEachInstanceField(
-        (ClassElement enclosing, Element field) {
-          if (field.name == JavaScriptMapConstant.LENGTH_NAME) {
-            arguments.add(
-                new jsAst.LiteralNumber('${constant.keyList.entries.length}'));
-          } else if (field.name == JavaScriptMapConstant.JS_OBJECT_NAME) {
-            arguments.add(jsMap());
-          } else if (field.name == JavaScriptMapConstant.KEYS_NAME) {
-            arguments.add(constantEmitter.reference(constant.keyList));
-          } else if (field.name == JavaScriptMapConstant.PROTO_VALUE) {
-            assert(constant.protoValue != null);
-            arguments.add(constantEmitter.reference(constant.protoValue));
-          } else if (field.name == JavaScriptMapConstant.JS_DATA_NAME) {
-            arguments.add(jsGeneralMap());
-          } else {
-            compiler.internalError(field,
-                "Compiler has unexpected field ${field.name} for "
-                "${className}.");
-          }
-          emittedArgumentCount++;
-        },
-        includeSuperAndInjectedMembers: true);
-    if ((className == JavaScriptMapConstant.DART_STRING_CLASS &&
-         emittedArgumentCount != 3) ||
-        (className == JavaScriptMapConstant.DART_PROTO_CLASS &&
-         emittedArgumentCount != 4) ||
-        (className == JavaScriptMapConstant.DART_GENERAL_CLASS &&
-         emittedArgumentCount != 1)) {
-      compiler.internalError(classElement,
-          "Compiler and ${className} disagree on number of fields.");
-    }
-
-    jsAst.Expression value =
-        new jsAst.New(getJsConstructor(classElement), arguments);
-    return maybeAddTypeArguments(constant.type, value);
-  }
-
-  JavaScriptBackend get backend => compiler.backend;
-
-  jsAst.PropertyAccess getHelperProperty(Element helper) {
-    return backend.namer.elementAccess(helper);
-  }
-
-  jsAst.Expression visitType(TypeConstantValue constant) {
-    DartType type = constant.representedType;
-    String name = namer.getRuntimeTypeName(type.element);
-    jsAst.Expression typeName = new jsAst.LiteralString("'$name'");
-    return new jsAst.Call(getHelperProperty(backend.getCreateRuntimeType()),
-                          [typeName]);
-  }
-
-  jsAst.Expression visitInterceptor(InterceptorConstantValue constant) {
-    return new jsAst.PropertyAccess.field(
-        getJsConstructor(constant.dispatchedType.element),
-        'prototype');
-  }
-
-  jsAst.Expression visitDummy(DummyConstantValue constant) {
-    return new jsAst.LiteralNumber('0');
-  }
-
-  jsAst.Expression visitConstructed(ConstructedConstantValue constant) {
-    Element element = constant.type.element;
-    if (element.isForeign(backend)
-        && element.name == 'JS_CONST') {
-      StringConstantValue str = constant.fields[0];
-      String value = str.primitiveValue.slowToString();
-      return new jsAst.LiteralExpression(stripComments(value));
-    }
-    jsAst.New instantiation = new jsAst.New(
-        getJsConstructor(constant.type.element),
-        _array(constant.fields));
-    return maybeAddTypeArguments(constant.type, instantiation);
-  }
-
-  String stripComments(String rawJavaScript) {
-    return rawJavaScript.replaceAll(COMMENT_RE, '');
-  }
-
-  List<jsAst.Expression> _array(List<ConstantValue> values) {
-    List<jsAst.Expression> valueList = <jsAst.Expression>[];
-    for (int i = 0; i < values.length; i++) {
-      valueList.add(constantEmitter.reference(values[i]));
-    }
-    return valueList;
-  }
-
-  jsAst.Expression maybeAddTypeArguments(InterfaceType type,
-                                         jsAst.Expression value) {
-    if (type is InterfaceType &&
-        !type.treatAsRaw &&
-        backend.classNeedsRti(type.element)) {
-      InterfaceType interface = type;
-      RuntimeTypes rti = backend.rti;
-      Iterable<String> arguments = interface.typeArguments
-          .map((DartType type) =>
-              rti.getTypeRepresentationWithHashes(type, (_){}));
-      jsAst.Expression argumentList =
-          new jsAst.LiteralString('[${arguments.join(', ')}]');
-      return new jsAst.Call(getHelperProperty(backend.getSetRuntimeTypeInfo()),
-                            [value, argumentList]);
-    }
-    return value;
-  }
-
-  jsAst.Expression visitDeferred(DeferredConstantValue constant) {
-    return constantEmitter.reference(constant.referenced);
-  }
-}