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dart / sdk.git / 79e82f80cec2cd04df8abc4f00fe2affb4be07a2 / . / sdk / lib / _internal / compiler / implementation / js_emitter / code_emitter_task.dart
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// 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 dart2js.js_emitter;
/**
* Generates the code for all used classes in the program. Static fields (even
* in classes) are ignored, since they can be treated as non-class elements.
*
* The code for the containing (used) methods must exist in the [:universe:].
*/
class CodeEmitterTask extends CompilerTask {
final ContainerBuilder containerBuilder = new ContainerBuilder();
bool needsDefineClass = false;
bool needsMixinSupport = false;
bool needsLazyInitializer = false;
final Namer namer;
ConstantEmitter constantEmitter;
NativeEmitter nativeEmitter;
CodeBuffer mainBuffer;
final CodeBuffer deferredLibraries = new CodeBuffer();
final CodeBuffer deferredConstants = new CodeBuffer();
/** Shorter access to [isolatePropertiesName]. Both here in the code, as
well as in the generated code. */
String isolateProperties;
String classesCollector;
final Set<ClassElement> neededClasses = new Set<ClassElement>();
final Set<ClassElement> rtiNeededClasses = new Set<ClassElement>();
final List<ClassElement> regularClasses = <ClassElement>[];
final List<ClassElement> deferredClasses = <ClassElement>[];
final List<ClassElement> nativeClasses = <ClassElement>[];
final List<Selector> trivialNsmHandlers = <Selector>[];
final Map<String, String> mangledFieldNames = <String, String>{};
final Map<String, String> mangledGlobalFieldNames = <String, String>{};
final Set<String> recordedMangledNames = new Set<String>();
final Set<String> interceptorInvocationNames = new Set<String>();
/// A list of JS expressions that represent metadata, parameter names and
/// type, and return types.
final List<String> globalMetadata = [];
/// A map used to canonicalize the entries of globalMetadata.
final Map<String, int> globalMetadataMap = <String, int>{};
// TODO(ngeoffray): remove this field.
Set<ClassElement> instantiatedClasses;
JavaScriptBackend get backend => compiler.backend;
String get _ => space;
String get space => compiler.enableMinification ? "" : " ";
String get n => compiler.enableMinification ? "" : "\n";
String get N => compiler.enableMinification ? "\n" : ";\n";
/**
* Raw ClassElement symbols occuring in is-checks and type assertions. If the
* program contains parameterized checks `x is Set<int>` and
* `x is Set<String>` then the ClassElement `Set` will occur once in
* [checkedClasses].
*/
Set<ClassElement> checkedClasses;
/**
* The set of function types that checked, both explicity through tests of
* typedefs and implicitly through type annotations in checked mode.
*/
Set<FunctionType> checkedFunctionTypes;
Map<ClassElement, Set<FunctionType>> checkedGenericFunctionTypes =
new Map<ClassElement, Set<FunctionType>>();
Set<FunctionType> checkedNonGenericFunctionTypes =
new Set<FunctionType>();
/**
* List of expressions and statements that will be included in the
* precompiled function.
*
* To save space, dart2js normally generates constructors and accessors
* dynamically. This doesn't work in CSP mode, and may impact startup time
* negatively. So dart2js will emit these functions to a separate file that
* can be optionally included to support CSP mode or for faster startup.
*/
List<jsAst.Node> precompiledFunction = <jsAst.Node>[];
List<jsAst.Expression> precompiledConstructorNames = <jsAst.Expression>[];
// True if Isolate.makeConstantList is needed.
bool hasMakeConstantList = false;
/**
* For classes and libraries, record code for static/top-level members.
* Later, this code is emitted when the class or library is emitted.
* See [bufferForElement].
*/
// TODO(ahe): Generate statics with their class, and store only libraries in
// this map.
final Map<Element, List<CodeBuffer>> elementBuffers =
new Map<Element, List<CodeBuffer>>();
void registerDynamicFunctionTypeCheck(FunctionType functionType) {
ClassElement classElement = Types.getClassContext(functionType);
if (classElement != null) {
checkedGenericFunctionTypes.putIfAbsent(classElement,
() => new Set<FunctionType>()).add(functionType);
} else {
checkedNonGenericFunctionTypes.add(functionType);
}
}
final bool generateSourceMap;
Iterable<ClassElement> cachedClassesUsingTypeVariableTests;
Iterable<ClassElement> get classesUsingTypeVariableTests {
if (cachedClassesUsingTypeVariableTests == null) {
cachedClassesUsingTypeVariableTests = compiler.codegenWorld.isChecks
.where((DartType t) => t is TypeVariableType)
.map((TypeVariableType v) => v.element.getEnclosingClass())
.toList();
}
return cachedClassesUsingTypeVariableTests;
}
CodeEmitterTask(Compiler compiler, Namer namer, this.generateSourceMap)
: mainBuffer = new CodeBuffer(),
this.namer = namer,
constantEmitter = new ConstantEmitter(compiler, namer),
super(compiler) {
nativeEmitter = new NativeEmitter(this);
containerBuilder.task = this;
}
void addComment(String comment, CodeBuffer buffer) {
buffer.write(jsAst.prettyPrint(js.comment(comment), compiler));
}
void computeRequiredTypeChecks() {
assert(checkedClasses == null && checkedFunctionTypes == null);
backend.rti.addImplicitChecks(compiler.codegenWorld,
classesUsingTypeVariableTests);
checkedClasses = new Set<ClassElement>();
checkedFunctionTypes = new Set<FunctionType>();
compiler.codegenWorld.isChecks.forEach((DartType t) {
if (t is InterfaceType) {
checkedClasses.add(t.element);
} else if (t is FunctionType) {
checkedFunctionTypes.add(t);
}
});
}
ClassElement computeMixinClass(MixinApplicationElement mixinApplication) {
ClassElement mixin = mixinApplication.mixin;
while (mixin.isMixinApplication) {
mixinApplication = mixin;
mixin = mixinApplication.mixin;
}
return mixin;
}
jsAst.Expression constantReference(Constant value) {
return constantEmitter.reference(value);
}
jsAst.Expression constantInitializerExpression(Constant value) {
return constantEmitter.initializationExpression(value);
}
String get name => 'CodeEmitter';
String get currentGenerateAccessorName
=> '${namer.CURRENT_ISOLATE}.\$generateAccessor';
String get generateAccessorHolder
=> '$isolatePropertiesName.\$generateAccessor';
String get finishClassesProperty
=> r'$finishClasses';
String get finishClassesName
=> '${namer.isolateName}.$finishClassesProperty';
String get finishIsolateConstructorName
=> '${namer.isolateName}.\$finishIsolateConstructor';
String get isolatePropertiesName
=> '${namer.isolateName}.${namer.isolatePropertiesName}';
String get lazyInitializerName
=> '${namer.isolateName}.\$lazy';
// Compact field specifications. The format of the field specification is
// <accessorName>:<fieldName><suffix> where the suffix and accessor name
// prefix are optional. The suffix directs the generation of getter and
// setter methods. Each of the getter and setter has two bits to determine
// the calling convention. Setter listed below, getter is similar.
//
// 00: no setter
// 01: function(value) { this.field = value; }
// 10: function(receiver, value) { receiver.field = value; }
// 11: function(receiver, value) { this.field = value; }
//
// The suffix encodes 4 bits using three ASCII ranges of non-identifier
// characters.
static const FIELD_CODE_CHARACTERS = r"<=>?@{|}~%&'()*";
static const NO_FIELD_CODE = 0;
static const FIRST_FIELD_CODE = 1;
static const RANGE1_FIRST = 0x3c; // <=>?@ encodes 1..5
static const RANGE1_LAST = 0x40;
static const RANGE2_FIRST = 0x7b; // {|}~ encodes 6..9
static const RANGE2_LAST = 0x7e;
static const RANGE3_FIRST = 0x25; // %&'()*+ encodes 10..16
static const RANGE3_LAST = 0x2b;
static const REFLECTION_MARKER = 0x2d;
jsAst.FunctionDeclaration get generateAccessorFunction {
const RANGE1_SIZE = RANGE1_LAST - RANGE1_FIRST + 1;
const RANGE2_SIZE = RANGE2_LAST - RANGE2_FIRST + 1;
const RANGE1_ADJUST = - (FIRST_FIELD_CODE - RANGE1_FIRST);
const RANGE2_ADJUST = - (FIRST_FIELD_CODE + RANGE1_SIZE - RANGE2_FIRST);
const RANGE3_ADJUST =
- (FIRST_FIELD_CODE + RANGE1_SIZE + RANGE2_SIZE - RANGE3_FIRST);
String receiverParamName = compiler.enableMinification ? "r" : "receiver";
String valueParamName = compiler.enableMinification ? "v" : "value";
String reflectableField = namer.reflectableField;
// function generateAccessor(field, prototype, cls) {
jsAst.Fun fun = js.fun(['field', 'accessors', 'cls'], [
js('var len = field.length'),
js('var code = field.charCodeAt(len - 1)'),
js('var reflectable = false'),
js.if_('code == $REFLECTION_MARKER', [
js('len--'),
js('code = field.charCodeAt(len - 1)'),
js('field = field.substring(0, len)'),
js('reflectable = true')
]),
js('code = ((code >= $RANGE1_FIRST) && (code <= $RANGE1_LAST))'
' ? code - $RANGE1_ADJUST'
' : ((code >= $RANGE2_FIRST) && (code <= $RANGE2_LAST))'
' ? code - $RANGE2_ADJUST'
' : ((code >= $RANGE3_FIRST) && (code <= $RANGE3_LAST))'
' ? code - $RANGE3_ADJUST'
' : $NO_FIELD_CODE'),
// if (needsAccessor) {
js.if_('code', [
js('var getterCode = code & 3'),
js('var setterCode = code >> 2'),
js('var accessorName = field = field.substring(0, len - 1)'),
js('var divider = field.indexOf(":")'),
js.if_('divider > 0', [ // Colon never in first position.
js('accessorName = field.substring(0, divider)'),
js('field = field.substring(divider + 1)')
]),
// if (needsGetter) {
js.if_('getterCode', [
js('var args = (getterCode & 2) ? "$receiverParamName" : ""'),
js('var receiver = (getterCode & 1) ? "this" : "$receiverParamName"'),
js('var body = "return " + receiver + "." + field'),
js('var property ='
' cls + ".prototype.${namer.getterPrefix}" + accessorName + "="'),
js('var fn = "function(" + args + "){" + body + "}"'),
js.if_(
'reflectable',
js('accessors.push(property + "\$reflectable(" + fn + ");\\n")'),
js('accessors.push(property + fn + ";\\n")')),
]),
// if (needsSetter) {
js.if_('setterCode', [
js('var args = (setterCode & 2)'
' ? "$receiverParamName,${_}$valueParamName"'
' : "$valueParamName"'),
js('var receiver = (setterCode & 1) ? "this" : "$receiverParamName"'),
js('var body = receiver + "." + field + "$_=$_$valueParamName"'),
js('var property ='
' cls + ".prototype.${namer.setterPrefix}" + accessorName + "="'),
js('var fn = "function(" + args + "){" + body + "}"'),
js.if_(
'reflectable',
js('accessors.push(property + "\$reflectable(" + fn + ");\\n")'),
js('accessors.push(property + fn + ";\\n")')),
]),
]),
// return field;
js.return_('field')
]);
return new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('generateAccessor'),
fun);
}
List get defineClassFunction {
// First the class name, then the field names in an array and the members
// (inside an Object literal).
// The caller can also pass in the constructor as a function if needed.
//
// Example:
// defineClass("A", ["x", "y"], {
// foo$1: function(y) {
// print(this.x + y);
// },
// bar$2: function(t, v) {
// this.x = t - v;
// },
// });
var defineClass = js.fun(['name', 'cls', 'fields'], [
js('var accessors = []'),
js('var str = "function " + cls + "("'),
js('var body = ""'),
js.for_('var i = 0', 'i < fields.length', 'i++', [
js.if_('i != 0', js('str += ", "')),
js('var field = generateAccessor(fields[i], accessors, cls)'),
js('var parameter = "parameter_" + field'),
js('str += parameter'),
js('body += ("this." + field + " = " + parameter + ";\\n")')
]),
js('str += ") {\\n" + body + "}\\n"'),
js('str += cls + ".builtin\$cls=\\"" + name + "\\";\\n"'),
js('str += "\$desc=\$collectedClasses." + cls + ";\\n"'),
js('str += "if(\$desc instanceof Array) \$desc = \$desc[1];\\n"'),
js('str += cls + ".prototype = \$desc;\\n"'),
js.if_(
'typeof defineClass.name != "string"',
[js('str += cls + ".name=\\"" + cls + "\\";\\n"')]),
js('str += accessors.join("")'),
js.return_('str')
]);
// Declare a function called "generateAccessor". This is used in
// defineClassFunction (it's a local declaration in init()).
return [
generateAccessorFunction,
js('$generateAccessorHolder = generateAccessor'),
new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('defineClass'), defineClass) ];
}
/** Needs defineClass to be defined. */
List buildInheritFrom() {
return [
js('var inheritFrom = #',
js.fun([], [
new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('tmp'), js.fun([], [])),
js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
js.return_(js.fun(['constructor', 'superConstructor'], [
js('tmp.prototype = superConstructor.prototype'),
js('var object = new tmp()'),
js('var properties = constructor.prototype'),
js.forIn('member', 'properties',
js.if_('hasOwnProperty.call(properties, member)',
js('object[member] = properties[member]'))),
js('object.constructor = constructor'),
js('constructor.prototype = object'),
js.return_('object')
]))])())];
}
static const MAX_MINIFIED_LENGTH_FOR_DIFF_ENCODING = 4;
// If we need fewer than this many noSuchMethod handlers we can save space by
// just emitting them in JS, rather than emitting the JS needed to generate
// them at run time.
static const VERY_FEW_NO_SUCH_METHOD_HANDLERS = 10;
/**
* Adds (at runtime) the handlers to the Object class which catch calls to
* methods that the object does not have. The handlers create an invocation
* mirror object.
*
* The current version only gives you the minified name when minifying (when
* not minifying this method is not called).
*
* In order to generate the noSuchMethod handlers we only need the minified
* name of the method. We test the first character of the minified name to
* determine if it is a getter or a setter, and we use the arguments array at
* runtime to get the number of arguments and their values. If the method
* involves named arguments etc. then we don't handle it here, but emit the
* handler method directly on the Object class.
*
* The minified names are mostly 1-4 character names, which we emit in sorted
* order (primary key is length, secondary ordering is lexicographic). This
* gives an order like ... dD dI dX da ...
*
* Gzip is good with repeated text, but it can't diff-encode, so we do that
* for it. We encode the minified names in a comma-separated string, but all
* the 1-4 character names are encoded before the first comma as a series of
* base 26 numbers. The last digit of each number is lower case, the others
* are upper case, so 1 is "b" and 26 is "Ba".
*
* We think of the minified names as base 88 numbers using the ASCII
* characters from # to z. The base 26 numbers each encode the delta from
* the previous minified name to the next. So if there is a minified name
* called Df and the next is Dh, then they are 2971 and 2973 when thought of
* as base 88 numbers. The difference is 2, which is "c" in lower-case-
* terminated base 26.
*
* The reason we don't encode long minified names with this method is that
* decoding the base 88 numbers would overflow JavaScript's puny integers.
*
* There are some selectors that have a special calling convention (because
* they are called with the receiver as the first argument). They need a
* slightly different noSuchMethod handler, so we handle these first.
*/
void addTrivialNsmHandlers(List<jsAst.Node> statements) {
if (trivialNsmHandlers.length == 0) return;
// Sort by calling convention, JS name length and by JS name.
trivialNsmHandlers.sort((a, b) {
bool aIsIntercepted = backend.isInterceptedName(a.name);
bool bIsIntercepted = backend.isInterceptedName(b.name);
if (aIsIntercepted != bIsIntercepted) return aIsIntercepted ? -1 : 1;
String aName = namer.invocationMirrorInternalName(a);
String bName = namer.invocationMirrorInternalName(b);
if (aName.length != bName.length) return aName.length - bName.length;
return aName.compareTo(bName);
});
// Find out how many selectors there are with the special calling
// convention.
int firstNormalSelector = trivialNsmHandlers.length;
for (int i = 0; i < trivialNsmHandlers.length; i++) {
if (!backend.isInterceptedName(trivialNsmHandlers[i].name)) {
firstNormalSelector = i;
break;
}
}
// Get the short names (JS names, perhaps minified).
Iterable<String> shorts = trivialNsmHandlers.map((selector) =>
namer.invocationMirrorInternalName(selector));
final diffShorts = <String>[];
var diffEncoding = new StringBuffer();
// Treat string as a number in base 88 with digits in ASCII order from # to
// z. The short name sorting is based on length, and uses ASCII order for
// equal length strings so this means that names are ascending. The hash
// character, #, is never given as input, but we need it because it's the
// implicit leading zero (otherwise we could not code names with leading
// dollar signs).
int fromBase88(String x) {
int answer = 0;
for (int i = 0; i < x.length; i++) {
int c = x.codeUnitAt(i);
// No support for Unicode minified identifiers in JS.
assert(c >= $$ && c <= $z);
answer *= 88;
answer += c - $HASH;
}
return answer;
}
// Big endian encoding, A = 0, B = 1...
// A lower case letter terminates the number.
String toBase26(int x) {
int c = x;
var encodingChars = <int>[];
encodingChars.add($a + (c % 26));
while (true) {
c ~/= 26;
if (c == 0) break;
encodingChars.add($A + (c % 26));
}
return new String.fromCharCodes(encodingChars.reversed.toList());
}
bool minify = compiler.enableMinification;
bool useDiffEncoding = minify && shorts.length > 30;
int previous = 0;
int nameCounter = 0;
for (String short in shorts) {
// Emit period that resets the diff base to zero when we switch to normal
// calling convention (this avoids the need to code negative diffs).
if (useDiffEncoding && nameCounter == firstNormalSelector) {
diffEncoding.write(".");
previous = 0;
}
if (short.length <= MAX_MINIFIED_LENGTH_FOR_DIFF_ENCODING &&
useDiffEncoding) {
int base63 = fromBase88(short);
int diff = base63 - previous;
previous = base63;
String base26Diff = toBase26(diff);
diffEncoding.write(base26Diff);
} else {
if (useDiffEncoding || diffEncoding.length != 0) {
diffEncoding.write(",");
}
diffEncoding.write(short);
}
nameCounter++;
}
// Startup code that loops over the method names and puts handlers on the
// Object class to catch noSuchMethod invocations.
ClassElement objectClass = compiler.objectClass;
String createInvocationMirror = namer.isolateAccess(
backend.getCreateInvocationMirror());
String noSuchMethodName = namer.publicInstanceMethodNameByArity(
Compiler.NO_SUCH_METHOD, Compiler.NO_SUCH_METHOD_ARG_COUNT);
var type = 0;
if (useDiffEncoding) {
statements.addAll([
js('var objectClassObject = '
' collectedClasses["${namer.getNameOfClass(objectClass)}"],'
' shortNames = "$diffEncoding".split(","),'
' nameNumber = 0,'
' diffEncodedString = shortNames[0],'
' calculatedShortNames = [0, 1]'), // 0, 1 are args for splice.
js.if_('objectClassObject instanceof Array',
js('objectClassObject = objectClassObject[1]')),
js.for_('var i = 0', 'i < diffEncodedString.length', 'i++', [
js('var codes = [],'
' diff = 0,'
' digit = diffEncodedString.charCodeAt(i)'),
js.if_('digit == ${$PERIOD}', [
js('nameNumber = 0'),
js('digit = diffEncodedString.charCodeAt(++i)')
]),
js.while_('digit <= ${$Z}', [
js('diff *= 26'),
js('diff += (digit - ${$A})'),
js('digit = diffEncodedString.charCodeAt(++i)')
]),
js('diff *= 26'),
js('diff += (digit - ${$a})'),
js('nameNumber += diff'),
js.for_('var remaining = nameNumber',
'remaining > 0',
'remaining = (remaining / 88) | 0', [
js('codes.unshift(${$HASH} + remaining % 88)')
]),
js('calculatedShortNames.push('
' String.fromCharCode.apply(String, codes))')
]),
js('shortNames.splice.apply(shortNames, calculatedShortNames)')
]);
} else {
// No useDiffEncoding version.
Iterable<String> longs = trivialNsmHandlers.map((selector) =>
selector.invocationMirrorMemberName);
String longNamesConstant = minify ? "" :
',longNames = "${longs.join(",")}".split(",")';
statements.add(
js('var objectClassObject = '
' collectedClasses["${namer.getNameOfClass(objectClass)}"],'
' shortNames = "$diffEncoding".split(",")'
' $longNamesConstant'));
statements.add(
js.if_('objectClassObject instanceof Array',
js('objectClassObject = objectClassObject[1]')));
}
String sliceOffset = ', (j < $firstNormalSelector) ? 1 : 0';
if (firstNormalSelector == 0) sliceOffset = '';
if (firstNormalSelector == shorts.length) sliceOffset = ', 1';
String whatToPatch = nativeEmitter.handleNoSuchMethod ?
"Object.prototype" :
"objectClassObject";
var params = ['name', 'short', 'type'];
var sliceOffsetParam = '';
var slice = 'Array.prototype.slice.call';
if (!sliceOffset.isEmpty) {
sliceOffsetParam = ', sliceOffset';
params.add('sliceOffset');
}
statements.addAll([
js.for_('var j = 0', 'j < shortNames.length', 'j++', [
js('var type = 0'),
js('var short = shortNames[j]'),
js.if_('short[0] == "${namer.getterPrefix[0]}"', js('type = 1')),
js.if_('short[0] == "${namer.setterPrefix[0]}"', js('type = 2')),
// Generate call to:
// createInvocationMirror(String name, internalName, type, arguments,
// argumentNames)
js('$whatToPatch[short] = #(${minify ? "shortNames" : "longNames"}[j], '
'short, type$sliceOffset)',
js.fun(params, [js.return_(js.fun([],
[js.return_(js(
'this.$noSuchMethodName('
'this, '
'$createInvocationMirror('
'name, short, type, '
'$slice(arguments$sliceOffsetParam), []))'))]))]))
])
]);
}
jsAst.Fun get finishClassesFunction {
// Class descriptions are collected in a JS object.
// 'finishClasses' takes all collected descriptions and sets up
// the prototype.
// Once set up, the constructors prototype field satisfy:
// - it contains all (local) members.
// - its internal prototype (__proto__) points to the superclass'
// prototype field.
// - the prototype's constructor field points to the JavaScript
// constructor.
// For engines where we have access to the '__proto__' we can manipulate
// the object literal directly. For other engines we have to create a new
// object and copy over the members.
String reflectableField = namer.reflectableField;
List<jsAst.Node> statements = [
js('var pendingClasses = {}'),
js.if_('!init.allClasses', js('init.allClasses = {}')),
js('var allClasses = init.allClasses'),
optional(
DEBUG_FAST_OBJECTS,
js('print("Number of classes: "'
r' + Object.getOwnPropertyNames($$).length)')),
js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
js.if_('typeof dart_precompiled == "function"',
[js('var constructors = dart_precompiled(collectedClasses)')],
[js('var combinedConstructorFunction = "function \$reflectable(fn){'
'fn.$reflectableField=1;return fn};\\n"+ "var \$desc;\\n"'),
js('var constructorsList = []')]),
js.forIn('cls', 'collectedClasses', [
js.if_('hasOwnProperty.call(collectedClasses, cls)', [
js('var desc = collectedClasses[cls]'),
js.if_('desc instanceof Array', js('desc = desc[1]')),
/* The 'fields' are either a constructor function or a
* string encoding fields, constructor and superclass. Get
* the superclass and the fields in the format
* '[name/]Super;field1,field2'
* from the null-string property on the descriptor.
* The 'name/' is optional and contains the name that should be used
* when printing the runtime type string. It is used, for example, to
* print the runtime type JSInt as 'int'.
*/
js('var classData = desc[""], supr, name = cls, fields = classData'),
optional(
backend.hasRetainedMetadata,
js.if_('typeof classData == "object" && '
'classData instanceof Array',
[js('classData = fields = classData[0]')])),
js.if_('typeof classData == "string"', [
js('var split = classData.split("/")'),
js.if_('split.length == 2', [
js('name = split[0]'),
js('fields = split[1]')
])
]),
js('var s = fields.split(";")'),
js('fields = s[1] == "" ? [] : s[1].split(",")'),
js('supr = s[0]'),
optional(needsMixinSupport, js.if_('supr && supr.indexOf("+") > 0', [
js('s = supr.split("+")'),
js('supr = s[0]'),
js('var mixin = collectedClasses[s[1]]'),
js.if_('mixin instanceof Array', js('mixin = mixin[1]')),
js.forIn('d', 'mixin', [
js.if_('hasOwnProperty.call(mixin, d)'
'&& !hasOwnProperty.call(desc, d)',
js('desc[d] = mixin[d]'))
]),
])),
js.if_('typeof dart_precompiled != "function"',
[js('combinedConstructorFunction +='
' defineClass(name, cls, fields)'),
js('constructorsList.push(cls)')]),
js.if_('supr', js('pendingClasses[cls] = supr'))
])
]),
js.if_('typeof dart_precompiled != "function"',
[js('combinedConstructorFunction +='
' "return [\\n " + constructorsList.join(",\\n ") + "\\n]"'),
js('var constructors ='
' new Function("\$collectedClasses", combinedConstructorFunction)'
'(collectedClasses)'),
js('combinedConstructorFunction = null')]),
js.for_('var i = 0', 'i < constructors.length', 'i++', [
js('var constructor = constructors[i]'),
js('var cls = constructor.name'),
js('var desc = collectedClasses[cls]'),
js('var globalObject = isolateProperties'),
js.if_('desc instanceof Array', [
js('globalObject = desc[0] || isolateProperties'),
js('desc = desc[1]')
]),
optional(backend.isTreeShakingDisabled,
js('constructor["${namer.metadataField}"] = desc')),
js('allClasses[cls] = constructor'),
js('globalObject[cls] = constructor'),
]),
js('constructors = null'),
js('var finishedClasses = {}'),
buildFinishClass(),
];
addTrivialNsmHandlers(statements);
statements.add(
js.forIn('cls', 'pendingClasses', js('finishClass(cls)'))
);
// function(collectedClasses,
// isolateProperties,
// existingIsolateProperties)
return js.fun(['collectedClasses', 'isolateProperties',
'existingIsolateProperties'], statements);
}
jsAst.Node optional(bool condition, jsAst.Node node) {
return condition ? node : new jsAst.EmptyStatement();
}
jsAst.FunctionDeclaration buildFinishClass() {
// function finishClass(cls) {
jsAst.Fun fun = js.fun(['cls'], [
// TODO(8540): Remove this work around.
/* Opera does not support 'getOwnPropertyNames'. Therefore we use
hasOwnProperty instead. */
js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
// if (hasOwnProperty.call(finishedClasses, cls)) return;
js.if_('hasOwnProperty.call(finishedClasses, cls)',
js.return_()),
js('finishedClasses[cls] = true'),
js('var superclass = pendingClasses[cls]'),
// The superclass is only false (empty string) for Dart's Object class.
// The minifier together with noSuchMethod can put methods on the
// Object.prototype object, and they show through here, so we check that
// we have a string.
js.if_('!superclass || typeof superclass != "string"', js.return_()),
js('finishClass(superclass)'),
js('var constructor = allClasses[cls]'),
js('var superConstructor = allClasses[superclass]'),
js.if_(js('!superConstructor'),
js('superConstructor ='
'existingIsolateProperties[superclass]')),
js('prototype = inheritFrom(constructor, superConstructor)'),
]);
return new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('finishClass'),
fun);
}
jsAst.Fun get finishIsolateConstructorFunction {
// We replace the old Isolate function with a new one that initializes
// all its fields with the initial (and often final) value of all globals.
//
// We also copy over old values like the prototype, and the
// isolateProperties themselves.
return js.fun('oldIsolate', [
js('var isolateProperties = oldIsolate.${namer.isolatePropertiesName}'),
new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('Isolate'),
js.fun([], [
js('var hasOwnProperty = Object.prototype.hasOwnProperty'),
js.forIn('staticName', 'isolateProperties',
js.if_('hasOwnProperty.call(isolateProperties, staticName)',
js('this[staticName] = isolateProperties[staticName]'))),
// Use the newly created object as prototype. In Chrome,
// this creates a hidden class for the object and makes
// sure it is fast to access.
new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('ForceEfficientMap'),
js.fun([], [])),
js('ForceEfficientMap.prototype = this'),
js('new ForceEfficientMap()')])),
js('Isolate.prototype = oldIsolate.prototype'),
js('Isolate.prototype.constructor = Isolate'),
js('Isolate.${namer.isolatePropertiesName} = isolateProperties'),
optional(needsDefineClass,
js('Isolate.$finishClassesProperty ='
' oldIsolate.$finishClassesProperty')),
optional(hasMakeConstantList,
js('Isolate.makeConstantList = oldIsolate.makeConstantList')),
js.return_('Isolate')]);
}
jsAst.Fun get lazyInitializerFunction {
// function(prototype, staticName, fieldName, getterName, lazyValue) {
var parameters = <String>['prototype', 'staticName', 'fieldName',
'getterName', 'lazyValue'];
return js.fun(parameters, addLazyInitializerLogic());
}
List addLazyInitializerLogic() {
String isolate = namer.CURRENT_ISOLATE;
String cyclicThrow = namer.isolateAccess(backend.getCyclicThrowHelper());
var lazies = [];
if (backend.rememberLazies) {
lazies = [
js.if_('!init.lazies', js('init.lazies = {}')),
js('init.lazies[fieldName] = getterName')];
}
return lazies..addAll([
js('var sentinelUndefined = {}'),
js('var sentinelInProgress = {}'),
js('prototype[fieldName] = sentinelUndefined'),
// prototype[getterName] = function()
js('prototype[getterName] = #', js.fun([], [
js('var result = $isolate[fieldName]'),
// try
js.try_([
js.if_('result === sentinelUndefined', [
js('$isolate[fieldName] = sentinelInProgress'),
// try
js.try_([
js('result = $isolate[fieldName] = lazyValue()'),
], finallyPart: [
// Use try-finally, not try-catch/throw as it destroys the
// stack trace.
// if (result === sentinelUndefined)
js.if_('result === sentinelUndefined', [
// if ($isolate[fieldName] === sentinelInProgress)
js.if_('$isolate[fieldName] === sentinelInProgress', [
js('$isolate[fieldName] = null'),
])
])
])
], /* else */ [
js.if_('result === sentinelInProgress',
js('$cyclicThrow(staticName)')
)
]),
// return result;
js.return_('result')
], finallyPart: [
js('$isolate[getterName] = #',
js.fun([], [js.return_('this[fieldName]')]))
])
]))
]);
}
List buildDefineClassAndFinishClassFunctionsIfNecessary() {
if (!needsDefineClass) return [];
return defineClassFunction
..addAll(buildInheritFrom())
..addAll([
js('$finishClassesName = #', finishClassesFunction)
]);
}
List buildLazyInitializerFunctionIfNecessary() {
if (!needsLazyInitializer) return [];
return [js('$lazyInitializerName = #', lazyInitializerFunction)];
}
List buildFinishIsolateConstructor() {
return [
js('$finishIsolateConstructorName = #', finishIsolateConstructorFunction)
];
}
void emitFinishIsolateConstructorInvocation(CodeBuffer buffer) {
String isolate = namer.isolateName;
buffer.write("$isolate = $finishIsolateConstructorName($isolate)$N");
}
bool fieldNeedsGetter(VariableElement field) {
assert(field.isField());
if (fieldAccessNeverThrows(field)) return false;
return backend.shouldRetainGetter(field)
|| compiler.codegenWorld.hasInvokedGetter(field, compiler);
}
bool fieldNeedsSetter(VariableElement field) {
assert(field.isField());
if (fieldAccessNeverThrows(field)) return false;
return (!field.modifiers.isFinalOrConst())
&& (backend.shouldRetainSetter(field)
|| compiler.codegenWorld.hasInvokedSetter(field, compiler));
}
// We never access a field in a closure (a captured variable) without knowing
// that it is there. Therefore we don't need to use a getter (that will throw
// if the getter method is missing), but can always access the field directly.
static bool fieldAccessNeverThrows(VariableElement field) {
return field is ClosureFieldElement;
}
/**
* Documentation wanted -- johnniwinther
*
* Invariant: [member] must be a declaration element.
*/
void addInstanceMember(Element member, ClassBuilder builder) {
assert(invariant(member, member.isDeclaration));
// TODO(floitsch): we don't need to deal with members of
// uninstantiated classes, that have been overwritten by subclasses.
if (member.isFunction()
|| member.isGenerativeConstructorBody()
|| member.isAccessor()) {
if (member.isAbstract(compiler)) return;
jsAst.Expression code = backend.generatedCode[member];
if (code == null) return;
String name = namer.getNameOfInstanceMember(member);
if (backend.isInterceptedMethod(member)) {
interceptorInvocationNames.add(name);
}
code = extendWithMetadata(member, code);
builder.addProperty(name, code);
String reflectionName = getReflectionName(member, name);
if (reflectionName != null) {
var reflectable =
js(backend.isAccessibleByReflection(member) ? '1' : '0');
builder.addProperty('+$reflectionName', reflectable);
jsAst.Node defaultValues = reifyDefaultArguments(member);
if (defaultValues != null) {
String unmangledName = member.name.slowToString();
builder.addProperty('*$unmangledName', defaultValues);
}
}
code = backend.generatedBailoutCode[member];
if (code != null) {
builder.addProperty(namer.getBailoutName(member), code);
}
FunctionElement function = member;
FunctionSignature parameters = function.computeSignature(compiler);
if (!parameters.optionalParameters.isEmpty) {
containerBuilder.addParameterStubs(function, builder.addProperty);
}
} else if (!member.isField()) {
compiler.internalError('unexpected kind: "${member.kind}"',
element: member);
}
containerBuilder.emitExtraAccessors(member, builder);
}
/// Returns the "reflection name" of an [Element] or [Selector].
/// The reflection name of a getter 'foo' is 'foo'.
/// The reflection name of a setter 'foo' is 'foo='.
/// The reflection name of a method 'foo' is 'foo:N:M:O', where N is the
/// number of required arguments, M is the number of optional arguments, and
/// O is the named arguments.
/// The reflection name of a constructor is similar to a regular method but
/// starts with 'new '.
/// The reflection name of class 'C' is 'C'.
/// An anonymous mixin application has no reflection name.
/// This is used by js_mirrors.dart.
String getReflectionName(elementOrSelector, String mangledName) {
SourceString name = elementOrSelector.name;
if (!backend.shouldRetainName(name)) {
if (name == const SourceString('') && elementOrSelector is Element) {
// Make sure to retain names of unnamed constructors.
if (!backend.isNeededForReflection(elementOrSelector)) return null;
} else {
return null;
}
}
// TODO(ahe): Enable the next line when I can tell the difference between
// an instance method and a global. They may have the same mangled name.
// if (recordedMangledNames.contains(mangledName)) return null;
recordedMangledNames.add(mangledName);
return getReflectionNameInternal(elementOrSelector, mangledName);
}
String getReflectionNameInternal(elementOrSelector, String mangledName) {
String name = elementOrSelector.name.slowToString();
if (elementOrSelector.isGetter()) return name;
if (elementOrSelector.isSetter()) {
if (!mangledName.startsWith(namer.setterPrefix)) return '$name=';
String base = mangledName.substring(namer.setterPrefix.length);
String getter = '${namer.getterPrefix}$base';
mangledFieldNames[getter] = name;
recordedMangledNames.add(getter);
// TODO(karlklose,ahe): we do not actually need to store information
// about the name of this setter in the output, but it is needed for
// marking the function as invokable by reflection.
return '$name=';
}
if (elementOrSelector is Selector
|| elementOrSelector.isFunction()
|| elementOrSelector.isConstructor()) {
int requiredParameterCount;
int optionalParameterCount;
String namedArguments = '';
bool isConstructor = false;
if (elementOrSelector is Selector) {
Selector selector = elementOrSelector;
requiredParameterCount = selector.argumentCount;
optionalParameterCount = 0;
namedArguments = namedParametersAsReflectionNames(selector);
} else {
FunctionElement function = elementOrSelector;
if (function.isConstructor()) {
isConstructor = true;
name = Elements.reconstructConstructorName(function);
}
requiredParameterCount = function.requiredParameterCount(compiler);
optionalParameterCount = function.optionalParameterCount(compiler);
FunctionSignature signature = function.computeSignature(compiler);
if (signature.optionalParametersAreNamed) {
var names = [];
for (Element e in signature.optionalParameters) {
names.add(e.name);
}
Selector selector = new Selector.call(
function.name,
function.getLibrary(),
requiredParameterCount,
names);
namedArguments = namedParametersAsReflectionNames(selector);
} else {
// Named parameters are handled differently by mirrors. For unnamed
// parameters, they are actually required if invoked
// reflectively. Also, if you have a method c(x) and c([x]) they both
// get the same mangled name, so they must have the same reflection
// name.
requiredParameterCount += optionalParameterCount;
optionalParameterCount = 0;
}
}
String suffix =
// TODO(ahe): We probably don't need optionalParameterCount in the
// reflection name.
'$name:$requiredParameterCount:$optionalParameterCount'
'$namedArguments';
return (isConstructor) ? 'new $suffix' : suffix;
}
Element element = elementOrSelector;
if (element.isGenerativeConstructorBody()) {
return null;
} else if (element.isClass()) {
ClassElement cls = element;
if (cls.isUnnamedMixinApplication) return null;
return cls.name.slowToString();
}
throw compiler.internalErrorOnElement(
element, 'Do not know how to reflect on this $element');
}
String namedParametersAsReflectionNames(Selector selector) {
if (selector.getOrderedNamedArguments().isEmpty) return '';
String names = selector.getOrderedNamedArguments().map(
(x) => x.slowToString()).join(':');
return ':$names';
}
/**
* Documentation wanted -- johnniwinther
*
* Invariant: [classElement] must be a declaration element.
*/
void emitInstanceMembers(ClassElement classElement,
ClassBuilder builder) {
assert(invariant(classElement, classElement.isDeclaration));
void visitMember(ClassElement enclosing, Element member) {
assert(invariant(classElement, member.isDeclaration));
if (member.isInstanceMember()) {
addInstanceMember(member, builder);
}
}
classElement.implementation.forEachMember(
visitMember,
includeBackendMembers: true);
if (identical(classElement, compiler.objectClass)
&& compiler.enabledNoSuchMethod) {
// Emit the noSuchMethod handlers on the Object prototype now,
// so that the code in the dynamicFunction helper can find
// them. Note that this helper is invoked before analyzing the
// full JS script.
if (!nativeEmitter.handleNoSuchMethod) {
emitNoSuchMethodHandlers(builder.addProperty);
}
}
}
void emitIsTests(ClassElement classElement, ClassBuilder builder) {
assert(invariant(classElement, classElement.isDeclaration));
void generateIsTest(Element other) {
if (other == compiler.objectClass && other != classElement) {
// Avoid emitting [:$isObject:] on all classes but [Object].
return;
}
other = backend.getImplementationClass(other);
builder.addProperty(namer.operatorIs(other), js('true'));
}
void generateIsFunctionTypeTest(FunctionType type) {
String operator = namer.operatorIsType(type);
builder.addProperty(operator, new jsAst.LiteralBool(true));
}
void generateFunctionTypeSignature(Element method, FunctionType type) {
assert(method.isImplementation);
jsAst.Expression thisAccess = new jsAst.This();
Node node = method.parseNode(compiler);
ClosureClassMap closureData =
compiler.closureToClassMapper.closureMappingCache[node];
if (closureData != null) {
Element thisElement =
closureData.freeVariableMapping[closureData.thisElement];
if (thisElement != null) {
assert(thisElement.hasFixedBackendName());
String thisName = thisElement.fixedBackendName();
thisAccess = js('this')[js.string(thisName)];
}
}
RuntimeTypes rti = backend.rti;
jsAst.Expression encoding = rti.getSignatureEncoding(type, thisAccess);
String operatorSignature = namer.operatorSignature();
builder.addProperty(operatorSignature, encoding);
}
void generateSubstitution(ClassElement cls, {bool emitNull: false}) {
if (cls.typeVariables.isEmpty) return;
RuntimeTypes rti = backend.rti;
jsAst.Expression expression;
bool needsNativeCheck = nativeEmitter.requiresNativeIsCheck(cls);
expression = rti.getSupertypeSubstitution(
classElement, cls, alwaysGenerateFunction: true);
if (expression == null && (emitNull || needsNativeCheck)) {
expression = new jsAst.LiteralNull();
}
if (expression != null) {
builder.addProperty(namer.substitutionName(cls), expression);
}
}
generateIsTestsOn(classElement, generateIsTest,
generateIsFunctionTypeTest, generateFunctionTypeSignature,
generateSubstitution);
}
void emitRuntimeTypeSupport(CodeBuffer buffer) {
addComment('Runtime type support', buffer);
RuntimeTypes rti = backend.rti;
TypeChecks typeChecks = rti.requiredChecks;
// Add checks to the constructors of instantiated classes.
for (ClassElement cls in typeChecks) {
// TODO(9556). The properties added to 'holder' should be generated
// directly as properties of the class object, not added later.
String holder = namer.isolateAccess(backend.getImplementationClass(cls));
for (TypeCheck check in typeChecks[cls]) {
ClassElement cls = check.cls;
buffer.write('$holder.${namer.operatorIs(cls)}$_=${_}true$N');
Substitution substitution = check.substitution;
if (substitution != null) {
CodeBuffer body =
jsAst.prettyPrint(substitution.getCode(rti, false), compiler);
buffer.write('$holder.${namer.substitutionName(cls)}$_=${_}');
buffer.write(body);
buffer.write('$N');
}
};
}
void addSignature(FunctionType type) {
jsAst.Expression encoding = rti.getTypeEncoding(type);
buffer.add('${namer.signatureName(type)}$_=${_}');
buffer.write(jsAst.prettyPrint(encoding, compiler));
buffer.add('$N');
}
checkedNonGenericFunctionTypes.forEach(addSignature);
checkedGenericFunctionTypes.forEach((_, Set<FunctionType> functionTypes) {
functionTypes.forEach(addSignature);
});
}
/**
* Returns the classes with constructors used as a 'holder' in
* [emitRuntimeTypeSupport].
* TODO(9556): Some cases will go away when the class objects are created as
* complete. Not all classes will go away while constructors are referenced
* from type substitutions.
*/
Set<ClassElement> classesModifiedByEmitRuntimeTypeSupport() {
TypeChecks typeChecks = backend.rti.requiredChecks;
Set<ClassElement> result = new Set<ClassElement>();
for (ClassElement cls in typeChecks) {
for (TypeCheck check in typeChecks[cls]) {
result.add(backend.getImplementationClass(cls));
break;
}
}
return result;
}
/**
* Calls [addField] for each of the fields of [element].
*
* [element] must be a [ClassElement] or a [LibraryElement].
*
* If [element] is a [ClassElement], the static fields of the class are
* visited if [visitStatics] is true and the instance fields are visited if
* [visitStatics] is false.
*
* If [element] is a [LibraryElement], [visitStatics] must be true.
*
* When visiting the instance fields of a class, the fields of its superclass
* are also visited if the class is instantiated.
*
* Invariant: [element] must be a declaration element.
*/
void visitFields(Element element, bool visitStatics, AcceptField f) {
assert(invariant(element, element.isDeclaration));
bool isClass = false;
bool isLibrary = false;
if (element.isClass()) {
isClass = true;
} else if (element.isLibrary()) {
isLibrary = true;
assert(invariant(element, visitStatics));
} else {
throw new SpannableAssertionFailure(
element, 'Expected a ClassElement or a LibraryElement.');
}
// If the class is never instantiated we still need to set it up for
// inheritance purposes, but we can simplify its JavaScript constructor.
bool isInstantiated =
compiler.codegenWorld.instantiatedClasses.contains(element);
void visitField(Element holder, VariableElement field) {
assert(invariant(element, field.isDeclaration));
SourceString name = field.name;
// Keep track of whether or not we're dealing with a field mixin
// into a native class.
bool isMixinNativeField =
isClass && element.isNative() && holder.isMixinApplication;
// See if we can dynamically create getters and setters.
// We can only generate getters and setters for [element] since
// the fields of super classes could be overwritten with getters or
// setters.
bool needsGetter = false;
bool needsSetter = false;
// We need to name shadowed fields differently, so they don't clash with
// the non-shadowed field.
bool isShadowed = false;
if (isLibrary || isMixinNativeField || holder == element) {
needsGetter = fieldNeedsGetter(field);
needsSetter = fieldNeedsSetter(field);
} else {
ClassElement cls = element;
isShadowed = cls.isShadowedByField(field);
}
if ((isInstantiated && !holder.isNative())
|| needsGetter
|| needsSetter) {
String accessorName = isShadowed
? namer.shadowedFieldName(field)
: namer.getNameOfField(field);
String fieldName = field.hasFixedBackendName()
? field.fixedBackendName()
: (isMixinNativeField ? name.slowToString() : accessorName);
bool needsCheckedSetter = false;
if (compiler.enableTypeAssertions
&& needsSetter
&& canGenerateCheckedSetter(field)) {
needsCheckedSetter = true;
needsSetter = false;
}
// Getters and setters with suffixes will be generated dynamically.
f(field, fieldName, accessorName, needsGetter, needsSetter,
needsCheckedSetter);
}
}
if (isLibrary) {
LibraryElement library = element;
library.implementation.forEachLocalMember((Element member) {
if (member.isField()) visitField(library, member);
});
} else if (visitStatics) {
ClassElement cls = element;
cls.implementation.forEachStaticField(visitField);
} else {
ClassElement cls = element;
// TODO(kasperl): We should make sure to only emit one version of
// overridden fields. Right now, we rely on the ordering so the
// fields pulled in from mixins are replaced with the fields from
// the class definition.
// If a class is not instantiated then we add the field just so we can
// generate the field getter/setter dynamically. Since this is only
// allowed on fields that are in [element] we don't need to visit
// superclasses for non-instantiated classes.
cls.implementation.forEachInstanceField(
visitField, includeSuperAndInjectedMembers: isInstantiated);
}
}
void generateReflectionDataForFieldGetterOrSetter(Element member,
String name,
ClassBuilder builder,
{bool isGetter}) {
Selector selector = isGetter
? new Selector.getter(member.name, member.getLibrary())
: new Selector.setter(member.name, member.getLibrary());
String reflectionName = getReflectionName(selector, name);
if (reflectionName != null) {
var reflectable =
js(backend.isAccessibleByReflection(member) ? '1' : '0');
builder.addProperty('+$reflectionName', reflectable);
}
}
void generateGetter(Element member, String fieldName, String accessorName,
ClassBuilder builder) {
String getterName = namer.getterNameFromAccessorName(accessorName);
ClassElement cls = member.getEnclosingClass();
String className = namer.getNameOfClass(cls);
String receiver = backend.isInterceptorClass(cls) ? 'receiver' : 'this';
List<String> args = backend.isInterceptedMethod(member) ? ['receiver'] : [];
precompiledFunction.add(
js('$className.prototype.$getterName = #',
js.fun(args, js.return_(js('$receiver.$fieldName')))));
if (backend.isNeededForReflection(member)) {
precompiledFunction.add(
js('$className.prototype.$getterName.${namer.reflectableField} = 1'));
}
}
void generateSetter(Element member, String fieldName, String accessorName,
ClassBuilder builder) {
String setterName = namer.setterNameFromAccessorName(accessorName);
ClassElement cls = member.getEnclosingClass();
String className = namer.getNameOfClass(cls);
String receiver = backend.isInterceptorClass(cls) ? 'receiver' : 'this';
List<String> args =
backend.isInterceptedMethod(member) ? ['receiver', 'v'] : ['v'];
precompiledFunction.add(
js('$className.prototype.$setterName = #',
js.fun(args, js.return_(js('$receiver.$fieldName = v')))));
if (backend.isNeededForReflection(member)) {
precompiledFunction.add(
js('$className.prototype.$setterName.${namer.reflectableField} = 1'));
}
}
bool canGenerateCheckedSetter(VariableElement field) {
// We never generate accessors for top-level/static fields.
if (!field.isInstanceMember()) return false;
DartType type = field.computeType(compiler).unalias(compiler);
if (type.element.isTypeVariable() ||
(type is FunctionType && type.containsTypeVariables) ||
type.treatAsDynamic ||
type.element == compiler.objectClass) {
// TODO(ngeoffray): Support type checks on type parameters.
return false;
}
return true;
}
void generateCheckedSetter(Element member,
String fieldName,
String accessorName,
ClassBuilder builder) {
assert(canGenerateCheckedSetter(member));
DartType type = member.computeType(compiler);
// TODO(ahe): Generate a dynamic type error here.
if (type.element.isErroneous()) return;
type = type.unalias(compiler);
// TODO(11273): Support complex subtype checks.
type = type.asRaw();
CheckedModeHelper helper =
backend.getCheckedModeHelper(type, typeCast: false);
FunctionElement helperElement = helper.getElement(compiler);
String helperName = namer.isolateAccess(helperElement);
List<jsAst.Expression> arguments = <jsAst.Expression>[js('v')];
if (helperElement.computeSignature(compiler).parameterCount != 1) {
arguments.add(js.string(namer.operatorIsType(type)));
}
String setterName = namer.setterNameFromAccessorName(accessorName);
String receiver = backend.isInterceptorClass(member.getEnclosingClass())
? 'receiver' : 'this';
List<String> args = backend.isInterceptedMethod(member)
? ['receiver', 'v']
: ['v'];
builder.addProperty(setterName,
js.fun(args,
js('$receiver.$fieldName = #', js(helperName)(arguments))));
generateReflectionDataForFieldGetterOrSetter(
member, setterName, builder, isGetter: false);
}
void emitClassConstructor(ClassElement classElement,
ClassBuilder builder,
String runtimeName) {
List<String> fields = <String>[];
if (!classElement.isNative()) {
visitFields(classElement, false,
(Element member,
String name,
String accessorName,
bool needsGetter,
bool needsSetter,
bool needsCheckedSetter) {
fields.add(name);
});
}
String constructorName = namer.getNameOfClass(classElement);
precompiledFunction.add(new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration(constructorName),
js.fun(fields, fields.map(
(name) => js('this.$name = $name')).toList())));
if (runtimeName == null) {
runtimeName = constructorName;
}
precompiledFunction.addAll([
js('$constructorName.builtin\$cls = "$runtimeName"'),
js.if_('!"name" in $constructorName',
js('$constructorName.name = "$constructorName"')),
js('\$desc=\$collectedClasses.$constructorName'),
js.if_('\$desc instanceof Array', js('\$desc = \$desc[1]')),
js('$constructorName.prototype = \$desc'),
]);
precompiledConstructorNames.add(js(constructorName));
}
jsAst.FunctionDeclaration buildPrecompiledFunction() {
// TODO(ahe): Compute a hash code.
String name = 'dart_precompiled';
precompiledFunction.add(
js.return_(
new jsAst.ArrayInitializer.from(precompiledConstructorNames)));
precompiledFunction.insert(0, js(r'var $desc'));
return new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration(name),
js.fun([r'$collectedClasses'], precompiledFunction));
}
void emitSuper(String superName, ClassBuilder builder) {
/* Do nothing. */
}
void emitRuntimeName(String runtimeName, ClassBuilder builder) {
/* Do nothing. */
}
void recordMangledField(Element member,
String accessorName,
String memberName) {
if (!backend.shouldRetainGetter(member)) return;
String previousName;
if (member.isInstanceMember()) {
previousName = mangledFieldNames.putIfAbsent(
'${namer.getterPrefix}$accessorName',
() => memberName);
} else {
previousName = mangledGlobalFieldNames.putIfAbsent(
accessorName,
() => memberName);
}
assert(invariant(member, previousName == memberName,
message: '$previousName != ${memberName}'));
}
/// Returns `true` if fields added.
bool emitFields(Element element,
ClassBuilder builder,
String superName,
{ bool classIsNative: false,
bool emitStatics: false,
bool onlyForRti: false }) {
assert(!emitStatics || !onlyForRti);
bool isClass = false;
bool isLibrary = false;
if (element.isClass()) {
isClass = true;
} else if (element.isLibrary()) {
isLibrary = false;
assert(invariant(element, emitStatics));
} else {
throw new SpannableAssertionFailure(
element, 'Must be a ClassElement or a LibraryElement');
}
StringBuffer buffer = new StringBuffer();
if (emitStatics) {
assert(invariant(element, superName == null, message: superName));
} else {
assert(invariant(element, superName != null));
String nativeName =
namer.getPrimitiveInterceptorRuntimeName(element);
if (nativeName != null) {
buffer.write('$nativeName/');
}
buffer.write('$superName;');
}
int bufferClassLength = buffer.length;
String separator = '';
var fieldMetadata = [];
bool hasMetadata = false;
if (!onlyForRti) {
visitFields(element, emitStatics,
(VariableElement field,
String name,
String accessorName,
bool needsGetter,
bool needsSetter,
bool needsCheckedSetter) {
// Ignore needsCheckedSetter - that is handled below.
bool needsAccessor = (needsGetter || needsSetter);
// We need to output the fields for non-native classes so we can auto-
// generate the constructor. For native classes there are no
// constructors, so we don't need the fields unless we are generating
// accessors at runtime.
if (!classIsNative || needsAccessor) {
buffer.write(separator);
separator = ',';
var metadata = buildMetadataFunction(field);
if (metadata != null) {
hasMetadata = true;
} else {
metadata = new jsAst.LiteralNull();
}
fieldMetadata.add(metadata);
recordMangledField(field, accessorName, field.name.slowToString());
if (!needsAccessor) {
// Emit field for constructor generation.
assert(!classIsNative);
buffer.write(name);
} else {
// Emit (possibly renaming) field name so we can add accessors at
// runtime.
buffer.write(accessorName);
if (name != accessorName) {
buffer.write(':$name');
// Only the native classes can have renaming accessors.
assert(classIsNative);
}
int getterCode = 0;
if (needsGetter) {
if (field.isInstanceMember()) {
// 01: function() { return this.field; }
// 10: function(receiver) { return receiver.field; }
// 11: function(receiver) { return this.field; }
bool isIntercepted = backend.fieldHasInterceptedGetter(field);
getterCode += isIntercepted ? 2 : 0;
getterCode += backend.isInterceptorClass(element) ? 0 : 1;
// TODO(sra): 'isInterceptorClass' might not be the correct test
// for methods forced to use the interceptor convention because
// the method's class was elsewhere mixed-in to an interceptor.
assert(!field.isInstanceMember() || getterCode != 0);
if (isIntercepted) {
interceptorInvocationNames.add(namer.getterName(field));
}
} else {
getterCode = 1;
}
}
int setterCode = 0;
if (needsSetter) {
if (field.isInstanceMember()) {
// 01: function(value) { this.field = value; }
// 10: function(receiver, value) { receiver.field = value; }
// 11: function(receiver, value) { this.field = value; }
bool isIntercepted = backend.fieldHasInterceptedSetter(field);
setterCode += isIntercepted ? 2 : 0;
setterCode += backend.isInterceptorClass(element) ? 0 : 1;
assert(!field.isInstanceMember() || setterCode != 0);
if (isIntercepted) {
interceptorInvocationNames.add(namer.setterName(field));
}
} else {
setterCode = 1;
}
}
int code = getterCode + (setterCode << 2);
if (code == 0) {
compiler.reportInternalError(
field, 'Internal error: code is 0 ($element/$field)');
} else {
buffer.write(FIELD_CODE_CHARACTERS[code - FIRST_FIELD_CODE]);
}
}
if (backend.isAccessibleByReflection(field)) {
buffer.write(new String.fromCharCode(REFLECTION_MARKER));
}
}
});
}
bool fieldsAdded = buffer.length > bufferClassLength;
String compactClassData = buffer.toString();
jsAst.Expression classDataNode = js.string(compactClassData);
if (hasMetadata) {
fieldMetadata.insert(0, classDataNode);
classDataNode = new jsAst.ArrayInitializer.from(fieldMetadata);
}
builder.addProperty('', classDataNode);
return fieldsAdded;
}
void emitClassGettersSetters(ClassElement classElement,
ClassBuilder builder) {
visitFields(classElement, false,
(VariableElement member,
String name,
String accessorName,
bool needsGetter,
bool needsSetter,
bool needsCheckedSetter) {
compiler.withCurrentElement(member, () {
if (needsCheckedSetter) {
assert(!needsSetter);
generateCheckedSetter(member, name, accessorName, builder);
}
if (needsGetter) {
generateGetter(member, name, accessorName, builder);
}
if (needsSetter) {
generateSetter(member, name, accessorName, builder);
}
});
});
}
/**
* Documentation wanted -- johnniwinther
*
* Invariant: [classElement] must be a declaration element.
*/
void generateClass(ClassElement classElement, CodeBuffer buffer) {
final onlyForRti = rtiNeededClasses.contains(classElement);
assert(invariant(classElement, classElement.isDeclaration));
assert(invariant(classElement, !classElement.isNative() || onlyForRti));
needsDefineClass = true;
String className = namer.getNameOfClass(classElement);
ClassElement superclass = classElement.superclass;
String superName = "";
if (superclass != null) {
superName = namer.getNameOfClass(superclass);
}
String runtimeName =
namer.getPrimitiveInterceptorRuntimeName(classElement);
if (classElement.isMixinApplication) {
String mixinName = namer.getNameOfClass(computeMixinClass(classElement));
superName = '$superName+$mixinName';
needsMixinSupport = true;
}
ClassBuilder builder = new ClassBuilder();
emitClassConstructor(classElement, builder, runtimeName);
emitSuper(superName, builder);
emitRuntimeName(runtimeName, builder);
emitFields(classElement, builder, superName, onlyForRti: onlyForRti);
emitClassGettersSetters(classElement, builder);
if (!classElement.isMixinApplication) {
emitInstanceMembers(classElement, builder);
}
emitIsTests(classElement, builder);
emitClassBuilderWithReflectionData(
className, classElement, builder, buffer);
}
void emitClassBuilderWithReflectionData(String className,
ClassElement classElement,
ClassBuilder builder,
CodeBuffer buffer) {
var metadata = buildMetadataFunction(classElement);
if (metadata != null) {
builder.addProperty("@", metadata);
}
if (backend.isNeededForReflection(classElement)) {
Link typeVars = classElement.typeVariables;
List properties = [];
for (TypeVariableType typeVar in typeVars) {
properties.add(js.string(typeVar.name.slowToString()));
properties.add(js.toExpression(reifyType(typeVar.element.bound)));
}
ClassElement superclass = classElement.superclass;
bool hasSuper = superclass != null;
if ((!properties.isEmpty && !hasSuper) ||
(hasSuper && superclass.typeVariables != typeVars)) {
builder.addProperty('<>', new jsAst.ArrayInitializer.from(properties));
}
}
List<CodeBuffer> classBuffers = elementBuffers[classElement];
if (classBuffers == null) {
classBuffers = [];
} else {
elementBuffers.remove(classElement);
}
CodeBuffer statics = new CodeBuffer();
statics.write('{$n');
bool hasStatics = false;
ClassBuilder staticsBuilder = new ClassBuilder();
if (emitFields(classElement, staticsBuilder, null, emitStatics: true)) {
hasStatics = true;
statics.write('"":$_');
statics.write(
jsAst.prettyPrint(staticsBuilder.properties.single.value, compiler));
statics.write(',$n');
}
for (CodeBuffer classBuffer in classBuffers) {
// TODO(ahe): What about deferred?
if (classBuffer != null) {
hasStatics = true;
statics.addBuffer(classBuffer);
}
}
statics.write('}$n');
if (hasStatics) {
builder.addProperty('static', new jsAst.Blob(statics));
}
// TODO(ahe): This method (generateClass) should return a jsAst.Expression.
if (!buffer.isEmpty) {
buffer.write(',$n$n');
}
buffer.write('$className:$_');
buffer.write(jsAst.prettyPrint(builder.toObjectInitializer(), compiler));
String reflectionName = getReflectionName(classElement, className);
if (reflectionName != null) {
List<int> interfaces = <int>[];
for (DartType interface in classElement.interfaces) {
interfaces.add(reifyType(interface));
}
buffer.write(',$n$n"+$reflectionName": $interfaces');
}
}
/// If this is true then we can generate the noSuchMethod handlers at startup
/// time, instead of them being emitted as part of the Object class.
bool get generateTrivialNsmHandlers => true;
int _selectorRank(Selector selector) {
int arity = selector.argumentCount * 3;
if (selector.isGetter()) return arity + 2;
if (selector.isSetter()) return arity + 1;
return arity;
}
int _compareSelectorNames(Selector selector1, Selector selector2) {
String name1 = selector1.name.toString();
String name2 = selector2.name.toString();
if (name1 != name2) return Comparable.compare(name1, name2);
return _selectorRank(selector1) - _selectorRank(selector2);
}
/**
* Returns a mapping containing all checked function types for which [type]
* can be a subtype. A function type is mapped to [:true:] if [type] is
* statically known to be a subtype of it and to [:false:] if [type] might
* be a subtype, provided with the right type arguments.
*/
// TODO(johnniwinther): Change to return a mapping from function types to
// a set of variable points and use this to detect statically/dynamically
// known subtype relations.
Map<FunctionType, bool> getFunctionTypeChecksOn(DartType type) {
Map<FunctionType, bool> functionTypeMap =
new LinkedHashMap<FunctionType, bool>();
for (FunctionType functionType in checkedFunctionTypes) {
if (compiler.types.isSubtype(type, functionType)) {
functionTypeMap[functionType] = true;
} else if (compiler.types.isPotentialSubtype(type, functionType)) {
functionTypeMap[functionType] = false;
}
}
// TODO(johnniwinther): Ensure stable ordering of the keys.
return functionTypeMap;
}
/**
* Generate "is tests" for [cls]: itself, and the "is tests" for the
* classes it implements and type argument substitution functions for these
* tests. We don't need to add the "is tests" of the super class because
* they will be inherited at runtime, but we may need to generate the
* substitutions, because they may have changed.
*/
void generateIsTestsOn(ClassElement cls,
void emitIsTest(Element element),
FunctionTypeTestEmitter emitIsFunctionTypeTest,
FunctionTypeSignatureEmitter emitFunctionTypeSignature,
SubstitutionEmitter emitSubstitution) {
if (checkedClasses.contains(cls)) {
emitIsTest(cls);
emitSubstitution(cls);
}
RuntimeTypes rti = backend.rti;
ClassElement superclass = cls.superclass;
bool haveSameTypeVariables(ClassElement a, ClassElement b) {
if (a.isClosure()) return true;
if (b.isUnnamedMixinApplication) {
return false;
}
return a.typeVariables == b.typeVariables;
}
if (superclass != null && superclass != compiler.objectClass &&
!haveSameTypeVariables(cls, superclass)) {
// We cannot inherit the generated substitutions, because the type
// variable layout for this class is different. Instead we generate
// substitutions for all checks and make emitSubstitution a NOP for the
// rest of this function.
Set<ClassElement> emitted = new Set<ClassElement>();
// TODO(karlklose): move the computation of these checks to
// RuntimeTypeInformation.
if (backend.classNeedsRti(cls)) {
emitSubstitution(superclass, emitNull: true);
emitted.add(superclass);
}
for (DartType supertype in cls.allSupertypes) {
ClassElement superclass = supertype.element;
if (classesUsingTypeVariableTests.contains(superclass)) {
emitSubstitution(superclass, emitNull: true);
emitted.add(superclass);
}
for (ClassElement check in checkedClasses) {
if (supertype.element == check && !emitted.contains(check)) {
// Generate substitution. If no substitution is necessary, emit
// [:null:] to overwrite a (possibly) existing substitution from the
// super classes.
emitSubstitution(check, emitNull: true);
emitted.add(check);
}
}
}
void emitNothing(_, {emitNull}) {};
emitSubstitution = emitNothing;
}
Set<Element> generated = new Set<Element>();
// A class that defines a [:call:] method implicitly implements
// [Function] and needs checks for all typedefs that are used in is-checks.
if (checkedClasses.contains(compiler.functionClass) ||
!checkedFunctionTypes.isEmpty) {
Element call = cls.lookupLocalMember(Compiler.CALL_OPERATOR_NAME);
if (call == null) {
// If [cls] is a closure, it has a synthetic call operator method.
call = cls.lookupBackendMember(Compiler.CALL_OPERATOR_NAME);
}
if (call != null && call.isFunction()) {
generateInterfacesIsTests(compiler.functionClass,
emitIsTest,
emitSubstitution,
generated);
FunctionType callType = call.computeType(compiler);
Map<FunctionType, bool> functionTypeChecks =
getFunctionTypeChecksOn(callType);
generateFunctionTypeTests(call, callType, functionTypeChecks,
emitFunctionTypeSignature, emitIsFunctionTypeTest);
}
}
for (DartType interfaceType in cls.interfaces) {
generateInterfacesIsTests(interfaceType.element, emitIsTest,
emitSubstitution, generated);
}
}
/**
* Generate "is tests" where [cls] is being implemented.
*/
void generateInterfacesIsTests(ClassElement cls,
void emitIsTest(ClassElement element),
SubstitutionEmitter emitSubstitution,
Set<Element> alreadyGenerated) {
void tryEmitTest(ClassElement check) {
if (!alreadyGenerated.contains(check) && checkedClasses.contains(check)) {
alreadyGenerated.add(check);
emitIsTest(check);
emitSubstitution(check);
}
};
tryEmitTest(cls);
for (DartType interfaceType in cls.interfaces) {
Element element = interfaceType.element;
tryEmitTest(element);
generateInterfacesIsTests(element, emitIsTest, emitSubstitution,
alreadyGenerated);
}
// We need to also emit "is checks" for the superclass and its supertypes.
ClassElement superclass = cls.superclass;
if (superclass != null) {
tryEmitTest(superclass);
generateInterfacesIsTests(superclass, emitIsTest, emitSubstitution,
alreadyGenerated);
}
}
static const int MAX_FUNCTION_TYPE_PREDICATES = 10;
/**
* Generates function type checks on [method] with type [methodType] against
* the function type checks in [functionTypeChecks].
*/
void generateFunctionTypeTests(
Element method,
FunctionType methodType,
Map<FunctionType, bool> functionTypeChecks,
FunctionTypeSignatureEmitter emitFunctionTypeSignature,
FunctionTypeTestEmitter emitIsFunctionTypeTest) {
bool hasDynamicFunctionTypeCheck = false;
int neededPredicates = 0;
functionTypeChecks.forEach((FunctionType functionType, bool knownSubtype) {
if (!knownSubtype) {
registerDynamicFunctionTypeCheck(functionType);
hasDynamicFunctionTypeCheck = true;
} else if (!backend.rti.isSimpleFunctionType(functionType)) {
// Simple function types are always checked using predicates and should
// not provoke generation of signatures.
neededPredicates++;
}
});
bool alwaysUseSignature = false;
if (hasDynamicFunctionTypeCheck ||
neededPredicates > MAX_FUNCTION_TYPE_PREDICATES) {
emitFunctionTypeSignature(method, methodType);
alwaysUseSignature = true;
}
functionTypeChecks.forEach((FunctionType functionType, bool knownSubtype) {
if (knownSubtype) {
if (backend.rti.isSimpleFunctionType(functionType)) {
// Simple function types are always checked using predicates.
emitIsFunctionTypeTest(functionType);
} else if (alwaysUseSignature) {
registerDynamicFunctionTypeCheck(functionType);
} else {
emitIsFunctionTypeTest(functionType);
}
}
});
}
/**
* Return a function that returns true if its argument is a class
* that needs to be emitted.
*/
Function computeClassFilter() {
if (backend.isTreeShakingDisabled) return (ClassElement cls) => true;
Set<ClassElement> unneededClasses = new Set<ClassElement>();
// The [Bool] class is not marked as abstract, but has a factory
// constructor that always throws. We never need to emit it.
unneededClasses.add(compiler.boolClass);
// Go over specialized interceptors and then constants to know which
// interceptors are needed.
Set<ClassElement> needed = new Set<ClassElement>();
backend.specializedGetInterceptors.forEach(
(_, Iterable<ClassElement> elements) {
needed.addAll(elements);
}
);
// Add interceptors referenced by constants.
needed.addAll(interceptorsReferencedFromConstants());
// Add unneeded interceptors to the [unneededClasses] set.
for (ClassElement interceptor in backend.interceptedClasses) {
if (!needed.contains(interceptor)
&& interceptor != compiler.objectClass) {
unneededClasses.add(interceptor);
}
}
return (ClassElement cls) => !unneededClasses.contains(cls);
}
Set<ClassElement> interceptorsReferencedFromConstants() {
Set<ClassElement> classes = new Set<ClassElement>();
ConstantHandler handler = compiler.constantHandler;
List<Constant> constants = handler.getConstantsForEmission();
for (Constant constant in constants) {
if (constant is InterceptorConstant) {
InterceptorConstant interceptorConstant = constant;
classes.add(interceptorConstant.dispatchedType.element);
}
}
return classes;
}
void emitFinishClassesInvocationIfNecessary(CodeBuffer buffer) {
if (needsDefineClass) {
buffer.write('$finishClassesName($classesCollector,'
'$_$isolateProperties,'
'${_}null)$N');
// Reset the map.
buffer.write("$classesCollector$_=${_}null$N$n");
}
}
void emitStaticFunction(CodeBuffer buffer,
String name,
jsAst.Expression functionExpression) {
// TODO(ahe): This method (emitStaticFunction) should return a
// jsAst.Expression.
if (!buffer.isEmpty) {
buffer.write(',$n$n');
}
buffer.write('$name:$_');
buffer.write(jsAst.prettyPrint(functionExpression, compiler));
}
void emitStaticFunctions(CodeBuffer eagerBuffer) {
bool isStaticFunction(Element element) =>
!element.isInstanceMember() && !element.isField();
Iterable<Element> elements =
backend.generatedCode.keys.where(isStaticFunction);
Set<Element> pendingElementsWithBailouts =
backend.generatedBailoutCode.keys
.where(isStaticFunction)
.toSet();
for (Element element in Elements.sortedByPosition(elements)) {
CodeBuffer buffer = bufferForElement(element, eagerBuffer);
jsAst.Expression code = backend.generatedCode[element];
String name = namer.getNameOfGlobalFunction(element);
code = extendWithMetadata(element, code);
emitStaticFunction(buffer, name, code);
String reflectionName = getReflectionName(element, name);
if (reflectionName != null) {
var reflectable = backend.isAccessibleByReflection(element) ? 1 : 0;
buffer.write(',$n$n"+$reflectionName":${_}$reflectable');
jsAst.Node defaultValues = reifyDefaultArguments(element);
if (defaultValues != null) {
String unmangledName = element.name.slowToString();
buffer.write(',$n$n"*$unmangledName":${_}');
buffer.write(jsAst.prettyPrint(defaultValues, compiler));
}
}
jsAst.Expression bailoutCode = backend.generatedBailoutCode[element];
if (bailoutCode != null) {
pendingElementsWithBailouts.remove(element);
emitStaticFunction(buffer, namer.getBailoutName(element), bailoutCode);
}
}
if (!pendingElementsWithBailouts.isEmpty) {
addComment('pendingElementsWithBailouts', eagerBuffer);
}
// Is it possible the primary function was inlined but the bailout was not?
for (Element element in
Elements.sortedByPosition(pendingElementsWithBailouts)) {
CodeBuffer buffer = bufferForElement(element, eagerBuffer);
jsAst.Expression bailoutCode = backend.generatedBailoutCode[element];
emitStaticFunction(buffer, namer.getBailoutName(element), bailoutCode);
}
}
void emitStaticNonFinalFieldInitializations(CodeBuffer buffer) {
ConstantHandler handler = compiler.constantHandler;
Iterable<VariableElement> staticNonFinalFields =
handler.getStaticNonFinalFieldsForEmission();
for (Element element in Elements.sortedByPosition(staticNonFinalFields)) {
// [:interceptedNames:] is handled in [emitInterceptedNames].
if (element == backend.interceptedNames) continue;
// `mapTypeToInterceptor` is handled in [emitMapTypeToInterceptor].
if (element == backend.mapTypeToInterceptor) continue;
compiler.withCurrentElement(element, () {
Constant initialValue = handler.getInitialValueFor(element);
jsAst.Expression init =
js('$isolateProperties.${namer.getNameOfGlobalField(element)} = #',
constantEmitter.referenceInInitializationContext(initialValue));
buffer.write(jsAst.prettyPrint(init, compiler));
buffer.write('$N');
});
}
}
void emitLazilyInitializedStaticFields(CodeBuffer buffer) {
ConstantHandler handler = compiler.constantHandler;
List<VariableElement> lazyFields =
handler.getLazilyInitializedFieldsForEmission();
if (!lazyFields.isEmpty) {
needsLazyInitializer = true;
for (VariableElement element in Elements.sortedByPosition(lazyFields)) {
assert(backend.generatedBailoutCode[element] == null);
jsAst.Expression code = backend.generatedCode[element];
// The code is null if we ended up not needing the lazily
// initialized field after all because of constant folding
// before code generation.
if (code == null) continue;
// The code only computes the initial value. We build the lazy-check
// here:
// lazyInitializer(prototype, 'name', fieldName, getterName, initial);
// The name is used for error reporting. The 'initial' must be a
// closure that constructs the initial value.
List<jsAst.Expression> arguments = <jsAst.Expression>[];
arguments.add(js(isolateProperties));
arguments.add(js.string(element.name.slowToString()));
arguments.add(js.string(namer.getNameX(element)));
arguments.add(js.string(namer.getLazyInitializerName(element)));
arguments.add(code);
jsAst.Expression getter = buildLazyInitializedGetter(element);
if (getter != null) {
arguments.add(getter);
}
jsAst.Expression init = js(lazyInitializerName)(arguments);
buffer.write(jsAst.prettyPrint(init, compiler));
buffer.write("$N");
}
}
}
jsAst.Expression buildLazyInitializedGetter(VariableElement element) {
// Nothing to do, the 'lazy' function will create the getter.
return null;
}
void emitCompileTimeConstants(CodeBuffer eagerBuffer) {
ConstantHandler handler = compiler.constantHandler;
List<Constant> constants = handler.getConstantsForEmission(
compareConstants);
for (Constant constant in constants) {
if (isConstantInlinedOrAlreadyEmitted(constant)) continue;
String name = namer.constantName(constant);
if (constant.isList()) emitMakeConstantListIfNotEmitted(eagerBuffer);
CodeBuffer buffer = bufferForConstant(constant, eagerBuffer);
jsAst.Expression init = js(
'${namer.globalObjectForConstant(constant)}.$name = #',
constantInitializerExpression(constant));
buffer.write(jsAst.prettyPrint(init, compiler));
buffer.write('$N');
}
}
bool isConstantInlinedOrAlreadyEmitted(Constant constant) {
if (constant.isFunction()) return true; // Already emitted.
if (constant.isPrimitive()) return true; // Inlined.
// The name is null when the constant is already a JS constant.
// TODO(floitsch): every constant should be registered, so that we can
// share the ones that take up too much space (like some strings).
if (namer.constantName(constant) == null) return true;
return false;
}
int compareConstants(Constant a, Constant b) {
// Inlined constants don't affect the order and sometimes don't even have
// names.
int cmp1 = isConstantInlinedOrAlreadyEmitted(a) ? 0 : 1;
int cmp2 = isConstantInlinedOrAlreadyEmitted(b) ? 0 : 1;
if (cmp1 + cmp2 < 2) return cmp1 - cmp2;
// Sorting by the long name clusters constants with the same constructor
// which compresses a tiny bit better.
int r = namer.constantLongName(a).compareTo(namer.constantLongName(b));
if (r != 0) return r;
// Resolve collisions in the long name by using the constant name (i.e. JS
// name) which is unique.
return namer.constantName(a).compareTo(namer.constantName(b));
}
void emitMakeConstantListIfNotEmitted(CodeBuffer buffer) {
if (hasMakeConstantList) return;
hasMakeConstantList = true;
buffer
..write(namer.isolateName)
..write(r'''.makeConstantList = function(list) {
list.immutable$list = true;
list.fixed$length = true;
return list;
};
''');
}
// Identify the noSuchMethod handlers that are so simple that we can
// generate them programatically.
bool isTrivialNsmHandler(
int type, List argNames, Selector selector, String internalName) {
if (!generateTrivialNsmHandlers) return false;
// Check for interceptor calling convention.
if (backend.isInterceptedName(selector.name)) {
// We can handle the calling convention used by intercepted names in the
// diff encoding, but we don't use that for non-minified code.
if (!compiler.enableMinification) return false;
String shortName = namer.invocationMirrorInternalName(selector);
if (shortName.length > MAX_MINIFIED_LENGTH_FOR_DIFF_ENCODING) {
return false;
}
}
// Check for named arguments.
if (argNames.length != 0) return false;
// Check for unexpected name (this doesn't really happen).
if (internalName.startsWith(namer.getterPrefix[0])) return type == 1;
if (internalName.startsWith(namer.setterPrefix[0])) return type == 2;
return type == 0;
}
void emitNoSuchMethodHandlers(DefineStubFunction defineStub) {
// Do not generate no such method handlers if there is no class.
if (compiler.codegenWorld.instantiatedClasses.isEmpty) return;
String noSuchMethodName = namer.publicInstanceMethodNameByArity(
Compiler.NO_SUCH_METHOD, Compiler.NO_SUCH_METHOD_ARG_COUNT);
// Keep track of the JavaScript names we've already added so we
// do not introduce duplicates (bad for code size).
Map<String, Selector> addedJsNames = new Map<String, Selector>();
void addNoSuchMethodHandlers(SourceString ignore, Set<Selector> selectors) {
// Cache the object class and type.
ClassElement objectClass = compiler.objectClass;
DartType objectType = objectClass.computeType(compiler);
for (Selector selector in selectors) {
TypeMask mask = selector.mask;
if (mask == null) {
mask = new TypeMask.subclass(compiler.objectClass);
}
if (!mask.needsNoSuchMethodHandling(selector, compiler)) continue;
String jsName = namer.invocationMirrorInternalName(selector);
addedJsNames[jsName] = selector;
String reflectionName = getReflectionName(selector, jsName);
if (reflectionName != null) {
mangledFieldNames[jsName] = reflectionName;
}
}
}
compiler.codegenWorld.invokedNames.forEach(addNoSuchMethodHandlers);
compiler.codegenWorld.invokedGetters.forEach(addNoSuchMethodHandlers);
compiler.codegenWorld.invokedSetters.forEach(addNoSuchMethodHandlers);
// Set flag used by generateMethod helper below. If we have very few
// handlers we use defineStub for them all, rather than try to generate them
// at runtime.
bool haveVeryFewNoSuchMemberHandlers =
(addedJsNames.length < VERY_FEW_NO_SUCH_METHOD_HANDLERS);
jsAst.Expression generateMethod(String jsName, Selector selector) {
// Values match JSInvocationMirror in js-helper library.
int type = selector.invocationMirrorKind;
List<jsAst.Parameter> parameters = <jsAst.Parameter>[];
CodeBuffer args = new CodeBuffer();
for (int i = 0; i < selector.argumentCount; i++) {
parameters.add(new jsAst.Parameter('\$$i'));
}
List<jsAst.Expression> argNames =
selector.getOrderedNamedArguments().map((SourceString name) =>
js.string(name.slowToString())).toList();
String methodName = selector.invocationMirrorMemberName;
String internalName = namer.invocationMirrorInternalName(selector);
String reflectionName = getReflectionName(selector, internalName);
if (!haveVeryFewNoSuchMemberHandlers &&
isTrivialNsmHandler(type, argNames, selector, internalName) &&
reflectionName == null) {
trivialNsmHandlers.add(selector);
return null;
}
assert(backend.isInterceptedName(Compiler.NO_SUCH_METHOD));
jsAst.Expression expression = js('this.$noSuchMethodName')(
[js('this'),
namer.elementAccess(backend.getCreateInvocationMirror())([
js.string(compiler.enableMinification ?
internalName : methodName),
js.string(internalName),
type,
new jsAst.ArrayInitializer.from(
parameters.map((param) => js(param.name)).toList()),
new jsAst.ArrayInitializer.from(argNames)])]);
parameters = backend.isInterceptedName(selector.name)
? ([new jsAst.Parameter('\$receiver')]..addAll(parameters))
: parameters;
return js.fun(parameters, js.return_(expression));
}
for (String jsName in addedJsNames.keys.toList()..sort()) {
Selector selector = addedJsNames[jsName];
jsAst.Expression method = generateMethod(jsName, selector);
if (method != null) {
defineStub(jsName, method);
String reflectionName = getReflectionName(selector, jsName);
if (reflectionName != null) {
bool accessible = compiler.world.allFunctions.filter(selector).any(
(Element e) => backend.isAccessibleByReflection(e));
defineStub('+$reflectionName', js(accessible ? '1' : '0'));
}
}
}
}
String buildIsolateSetup(CodeBuffer buffer,
Element appMain,
Element isolateMain) {
String mainAccess = "${namer.isolateStaticClosureAccess(appMain)}";
// Since we pass the closurized version of the main method to
// the isolate method, we must make sure that it exists.
return "${namer.isolateAccess(isolateMain)}($mainAccess)";
}
jsAst.Expression generateDispatchPropertyInitialization() {
return js('!#', js.fun([], [
js('var objectProto = Object.prototype'),
js.for_('var i = 0', null, 'i++', [
js('var property = "${generateDispatchPropertyName(0)}"'),
js.if_('i > 0', js('property = rootProperty + "_" + i')),
js.if_('!(property in objectProto)',
js.return_(
js('init.dispatchPropertyName = property')))])])());
}
String generateDispatchPropertyName(int seed) {
// TODO(sra): MD5 of contributing source code or URIs?
return '___dart_dispatch_record_ZxYxX_${seed}_';
}
emitMain(CodeBuffer buffer) {
if (compiler.isMockCompilation) return;
Element main = compiler.mainApp.find(Compiler.MAIN);
String mainCall = null;
if (compiler.hasIsolateSupport()) {
Element isolateMain =
compiler.isolateHelperLibrary.find(Compiler.START_ROOT_ISOLATE);
mainCall = buildIsolateSetup(buffer, main, isolateMain);
} else {
mainCall = '${namer.isolateAccess(main)}()';
}
if (backend.needToInitializeDispatchProperty) {
buffer.write(
jsAst.prettyPrint(generateDispatchPropertyInitialization(),
compiler));
buffer.write(N);
}
addComment('BEGIN invoke [main].', buffer);
// This code finds the currently executing script by listening to the
// onload event of all script tags and getting the first script which
// finishes. Since onload is called immediately after execution this should
// not substantially change execution order.
buffer.write('''
;(function (callback) {
if (typeof document === "undefined") {
callback(null);
return;
}
if (document.currentScript) {
callback(document.currentScript);
return;
}
var scripts = document.scripts;
function onLoad(event) {
for (var i = 0; i < scripts.length; ++i) {
scripts[i].removeEventListener("load", onLoad, false);
}
callback(event.target);
}
for (var i = 0; i < scripts.length; ++i) {
scripts[i].addEventListener("load", onLoad, false);
}
})(function(currentScript) {
init.currentScript = currentScript;
if (typeof dartMainRunner === "function") {
dartMainRunner(function() { ${mainCall}; });
} else {
${mainCall};
}
})$N''');
addComment('END invoke [main].', buffer);
}
void emitGetInterceptorMethod(CodeBuffer buffer,
String key,
Set<ClassElement> classes) {
jsAst.Statement buildReturnInterceptor(ClassElement cls) {
return js.return_(js(namer.isolateAccess(cls))['prototype']);
}
/**
* Build a JavaScrit AST node for doing a type check on
* [cls]. [cls] must be an 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.if_(condition, buildReturnInterceptor(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;
}
jsAst.Block block = new jsAst.Block.empty();
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.Return returnNumberClass = buildReturnInterceptor(
hasDouble ? backend.jsDoubleClass : backend.jsNumberClass);
if (hasInt) {
jsAst.Expression isInt = js('Math.floor(receiver) == receiver');
whenNumber = js.block([
js.if_(isInt, buildReturnInterceptor(backend.jsIntClass)),
returnNumberClass]);
} else {
whenNumber = returnNumberClass;
}
block.statements.add(
js.if_('(typeof receiver) == "number"',
whenNumber));
}
if (hasString) {
block.statements.add(buildInterceptorCheck(backend.jsStringClass));
}
if (hasNull) {
block.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.
block.statements.add(js.if_('receiver == null',
js.return_(js('receiver'))));
}
if (hasBool) {
block.statements.add(buildInterceptorCheck(backend.jsBoolClass));
}
// TODO(ahe): It might be faster to check for Array before
// function and bool.
if (hasArray) {
block.statements.add(buildInterceptorCheck(backend.jsArrayClass));
}
if (hasNative) {
block.statements.add(
js.if_(
js('(typeof receiver) != "object"'),
js.return_(js('receiver'))));
// if (receiver instanceof $.Object) return receiver;
// return $.getNativeInterceptor(receiver);
block.statements.add(
js.if_(js('receiver instanceof #',
js(namer.isolateAccess(compiler.objectClass))),
js.return_(js('receiver'))));
block.statements.add(
js.return_(
js(namer.isolateAccess(backend.getNativeInterceptorMethod))(
['receiver'])));
} else {
ClassElement jsUnknown = backend.jsUnknownJavaScriptObjectClass;
if (compiler.codegenWorld.instantiatedClasses.contains(jsUnknown)) {
block.statements.add(
js.if_(js('!(receiver instanceof #)',
js(namer.isolateAccess(compiler.objectClass))),
buildReturnInterceptor(jsUnknown)));
}
block.statements.add(js.return_(js('receiver')));
}
buffer.write(jsAst.prettyPrint(
js('${namer.globalObjectFor(compiler.interceptorsLibrary)}.$key = #',
js.fun(['receiver'], block)),
compiler));
buffer.write(N);
}
/**
* Emit all versions of the [:getInterceptor:] method.
*/
void emitGetInterceptorMethods(CodeBuffer buffer) {
addComment('getInterceptor methods', buffer);
Map<String, Set<ClassElement>> specializedGetInterceptors =
backend.specializedGetInterceptors;
for (String name in specializedGetInterceptors.keys.toList()..sort()) {
Set<ClassElement> classes = specializedGetInterceptors[name];
emitGetInterceptorMethod(buffer, name, classes);
}
}
/**
* Compute all the classes that must be emitted.
*/
void computeNeededClasses() {
instantiatedClasses =
compiler.codegenWorld.instantiatedClasses.where(computeClassFilter())
.toSet();
void addClassWithSuperclasses(ClassElement cls) {
neededClasses.add(cls);
for (ClassElement superclass = cls.superclass;
superclass != null;
superclass = superclass.superclass) {
neededClasses.add(superclass);
}
}
void addClassesWithSuperclasses(Iterable<ClassElement> classes) {
for (ClassElement cls in classes) {
addClassWithSuperclasses(cls);
}
}
// 1. We need to generate all classes that are instantiated.
addClassesWithSuperclasses(instantiatedClasses);
// 2. Add all classes used as mixins.
Set<ClassElement> mixinClasses = neededClasses
.where((ClassElement element) => element.isMixinApplication)
.map(computeMixinClass)
.toSet();
neededClasses.addAll(mixinClasses);
// 3. If we need noSuchMethod support, we run through all needed
// classes to figure out if we need the support on any native
// class. If so, we let the native emitter deal with it.
if (compiler.enabledNoSuchMethod) {
SourceString noSuchMethodName = Compiler.NO_SUCH_METHOD;
Selector noSuchMethodSelector = compiler.noSuchMethodSelector;
for (ClassElement element in neededClasses) {
if (!element.isNative()) continue;
Element member = element.lookupLocalMember(noSuchMethodName);
if (member == null) continue;
if (noSuchMethodSelector.applies(member, compiler)) {
nativeEmitter.handleNoSuchMethod = true;
break;
}
}
}
// 4. Find all classes needed for rti.
// It is important that this is the penultimate step, at this point,
// neededClasses must only contain classes that have been resolved and
// codegen'd. The rtiNeededClasses may contain additional classes, but
// these are thought to not have been instantiated, so we neeed to be able
// to identify them later and make sure we only emit "empty shells" without
// fields, etc.
computeRtiNeededClasses();
rtiNeededClasses.removeAll(neededClasses);
// rtiNeededClasses now contains only the "empty shells".
neededClasses.addAll(rtiNeededClasses);
// 5. Finally, sort the classes.
List<ClassElement> sortedClasses = Elements.sortedByPosition(neededClasses);
for (ClassElement element in sortedClasses) {
if (rtiNeededClasses.contains(element)) {
regularClasses.add(element);
} else if (Elements.isNativeOrExtendsNative(element)) {
// For now, native classes and related classes cannot be deferred.
nativeClasses.add(element);
if (!element.isNative()) {
assert(invariant(element, !isDeferred(element)));
regularClasses.add(element);
}
} else if (isDeferred(element)) {
deferredClasses.add(element);
} else {
regularClasses.add(element);
}
}
}
Set<ClassElement> computeRtiNeededClasses() {
void addClassWithSuperclasses(ClassElement cls) {
rtiNeededClasses.add(cls);
for (ClassElement superclass = cls.superclass;
superclass != null;
superclass = superclass.superclass) {
rtiNeededClasses.add(superclass);
}
}
void addClassesWithSuperclasses(Iterable<ClassElement> classes) {
for (ClassElement cls in classes) {
addClassWithSuperclasses(cls);
}
}
// 1. Add classes that are referenced by type arguments or substitutions in
// argument checks.
// TODO(karlklose): merge this case with 2 when unifying argument and
// object checks.
RuntimeTypes rti = backend.rti;
rti.getRequiredArgumentClasses(backend).forEach((ClassElement c) {
// Types that we represent with JS native types (like int and String) do
// not need a class definition as we use the interceptor classes instead.
if (!rti.isJsNative(c)) {
addClassWithSuperclasses(c);
}
});
// 2. Add classes that are referenced by substitutions in object checks and
// their superclasses.
TypeChecks requiredChecks =
rti.computeChecks(rtiNeededClasses, checkedClasses);
Set<ClassElement> classesUsedInSubstitutions =
rti.getClassesUsedInSubstitutions(backend, requiredChecks);
addClassesWithSuperclasses(classesUsedInSubstitutions);
// 3. Add classes that contain checked generic function types. These are
// needed to store the signature encoding.
for (FunctionType type in checkedFunctionTypes) {
ClassElement contextClass = Types.getClassContext(type);
if (contextClass != null) {
rtiNeededClasses.add(contextClass);
}
}
return rtiNeededClasses;
}
// 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) {
jsAst.Expression isNumber(String variable) {
return js('typeof $variable == "number"');
}
jsAst.Expression isNotObject(String variable) {
return js('typeof $variable != "object"');
}
jsAst.Expression isInt(String variable) {
return isNumber(variable).binary('&&',
js('Math.floor($variable) == $variable'));
}
jsAst.Expression tripleShiftZero(jsAst.Expression receiver) {
return receiver.binary('>>>', js('0'));
}
if (selector.isOperator()) {
String name = selector.name.stringValue;
if (name == '==') {
// Unfolds to:
// if (receiver == null) return a0 == null;
// if (typeof receiver != 'object') {
// return a0 != null && receiver === a0;
// }
List<jsAst.Statement> body = <jsAst.Statement>[];
body.add(js.if_('receiver == null', js.return_(js('a0 == null'))));
body.add(js.if_(
isNotObject('receiver'),
js.return_(js('a0 != null && receiver === a0'))));
return new jsAst.Block(body);
}
if (!classes.contains(backend.jsIntClass)
&& !classes.contains(backend.jsNumberClass)
&& !classes.contains(backend.jsDoubleClass)) {
return null;
}
if (selector.argumentCount == 1) {
// The following operators do not map to a JavaScript
// operator.
if (name == '~/' || name == '<<' || name == '%' || name == '>>') {
return null;
}
jsAst.Expression result = js('receiver').binary(name, js('a0'));
if (name == '&' || name == '|' || name == '^') {
result = tripleShiftZero(result);
}
// Unfolds to:
// if (typeof receiver == "number" && typeof a0 == "number")
// return receiver op a0;
return js.if_(
isNumber('receiver').binary('&&', isNumber('a0')),
js.return_(result));
} else if (name == 'unary-') {
// [: if (typeof receiver == "number") return -receiver :].
return js.if_(isNumber('receiver'),
js.return_(js('-receiver')));
} else {
assert(name == '~');
return js.if_(isInt('receiver'),
js.return_(js('~receiver >>> 0')));
}
} else if (selector.isIndex() || selector.isIndexSet()) {
// For an index operation, this code generates:
//
// if (receiver.constructor == Array || typeof receiver == "string") {
// if (a0 >>> 0 === a0 && a0 < receiver.length) {
// return receiver[a0];
// }
// }
//
// For an index set operation, this code generates:
//
// if (receiver.constructor == Array && !receiver.immutable$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 = classes.any((cls) {
return compiler.world.isSubtype(
backend.jsIndexingBehaviorInterface, cls);
});
// 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 isIntAndAboveZero = js('a0 >>> 0 === a0');
jsAst.Expression belowLength = js('a0 < receiver.length');
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 : left.binary('||', right);
}
if (selector.isIndex()) {
jsAst.Expression stringCheck = js('typeof receiver == "string"');
jsAst.Expression typeCheck;
if (containsArray) {
typeCheck = arrayCheck;
}
if (containsString) {
typeCheck = orExp(typeCheck, stringCheck);
}
if (containsJsIndexable) {
typeCheck = orExp(typeCheck, indexableCheck);
}
return js.if_(typeCheck,
js.if_(isIntAndAboveZero.binary('&&', belowLength),
js.return_(js('receiver[a0]'))));
} else {
jsAst.Expression typeCheck;
if (containsArray) {
typeCheck = arrayCheck;
}
if (containsJsIndexable) {
typeCheck = orExp(typeCheck, indexableCheck);
}
jsAst.Expression isImmutableArray = typeCheck.binary(
'&&', js(r'!receiver.immutable$list'));
return js.if_(isImmutableArray.binary(
'&&', isIntAndAboveZero.binary('&&', belowLength)),
js.return_(js('receiver[a0] = a1')));
}
}
return null;
}
void emitOneShotInterceptors(CodeBuffer buffer) {
List<String> names = backend.oneShotInterceptors.keys.toList();
names.sort();
for (String name in names) {
Selector selector = backend.oneShotInterceptors[name];
Set<ClassElement> classes =
backend.getInterceptedClassesOn(selector.name);
String getInterceptorName =
namer.getInterceptorName(backend.getInterceptorMethod, classes);
List<jsAst.Parameter> parameters = <jsAst.Parameter>[];
List<jsAst.Expression> arguments = <jsAst.Expression>[];
parameters.add(new jsAst.Parameter('receiver'));
arguments.add(js('receiver'));
if (selector.isSetter()) {
parameters.add(new jsAst.Parameter('value'));
arguments.add(js('value'));
} else {
for (int i = 0; i < selector.argumentCount; i++) {
String argName = 'a$i';
parameters.add(new jsAst.Parameter(argName));
arguments.add(js(argName));
}
}
List<jsAst.Statement> body = <jsAst.Statement>[];
jsAst.Statement optimizedPath =
fastPathForOneShotInterceptor(selector, classes);
if (optimizedPath != null) {
body.add(optimizedPath);
}
String invocationName = backend.namer.invocationName(selector);
String globalObject = namer.globalObjectFor(compiler.interceptorsLibrary);
body.add(js.return_(
js(globalObject)[getInterceptorName]('receiver')[invocationName](
arguments)));
jsAst.Expression assignment =
js('${globalObject}.$name = #', js.fun(parameters, body));
buffer.write(jsAst.prettyPrint(assignment, compiler));
buffer.write(N);
}
}
/**
* If [JSInvocationMirror._invokeOn] has been compiled, emit all the
* possible selector names that are intercepted into the
* [interceptedNames] top-level variable. The implementation of
* [_invokeOn] will use it to determine whether it should call the
* method with an extra parameter.
*/
void emitInterceptedNames(CodeBuffer buffer) {
// TODO(ahe): We should not generate the list of intercepted names at
// compile time, it can be generated automatically at runtime given
// subclasses of Interceptor (which can easily be identified).
if (!compiler.enabledInvokeOn) return;
// TODO(ahe): We should roll this into
// [emitStaticNonFinalFieldInitializations].
String name = backend.namer.getNameOfGlobalField(backend.interceptedNames);
int index = 0;
var invocationNames = interceptorInvocationNames.toList()..sort();
List<jsAst.ArrayElement> elements = invocationNames.map(
(String invocationName) {
jsAst.Literal str = js.string(invocationName);
return new jsAst.ArrayElement(index++, str);
}).toList();
jsAst.ArrayInitializer array =
new jsAst.ArrayInitializer(invocationNames.length, elements);
jsAst.Expression assignment = js('$isolateProperties.$name = #', array);
buffer.write(jsAst.prettyPrint(assignment, compiler));
buffer.write(N);
}
/**
* Emit initializer for [mapTypeToInterceptor] data structure used by
* [findInterceptorForType]. See declaration of [mapTypeToInterceptor] in
* `interceptors.dart`.
*/
void emitMapTypeToInterceptor(CodeBuffer buffer) {
// TODO(sra): Perhaps inject a constant instead?
// TODO(sra): Filter by subclasses of native types.
List<jsAst.Expression> elements = <jsAst.Expression>[];
ConstantHandler handler = compiler.constantHandler;
List<Constant> constants = handler.getConstantsForEmission();
for (Constant constant in constants) {
if (constant is TypeConstant) {
TypeConstant typeConstant = constant;
Element element = typeConstant.representedType.element;
if (element is ClassElement) {
ClassElement classElement = element;
elements.add(backend.emitter.constantReference(constant));
elements.add(js(namer.isolateAccess(classElement)));
}
}
}
jsAst.ArrayInitializer array = new jsAst.ArrayInitializer.from(elements);
String name =
backend.namer.getNameOfGlobalField(backend.mapTypeToInterceptor);
jsAst.Expression assignment = js('$isolateProperties.$name = #', array);
buffer.write(jsAst.prettyPrint(assignment, compiler));
buffer.write(N);
}
void emitInitFunction(CodeBuffer buffer) {
jsAst.Fun fun = js.fun([], [
js('$isolateProperties = {}'),
]
..addAll(buildDefineClassAndFinishClassFunctionsIfNecessary())
..addAll(buildLazyInitializerFunctionIfNecessary())
..addAll(buildFinishIsolateConstructor())
);
jsAst.FunctionDeclaration decl = new jsAst.FunctionDeclaration(
new jsAst.VariableDeclaration('init'), fun);
buffer.write(jsAst.prettyPrint(decl, compiler).getText());
if (compiler.enableMinification) buffer.write('\n');
}
/// The metadata function returns the metadata associated with
/// [element] in generated code. The metadata needs to be wrapped
/// in a function as it refers to constants that may not have been
/// constructed yet. For example, a class is allowed to be
/// annotated with itself. The metadata function is used by
/// mirrors_patch to implement DeclarationMirror.metadata.
jsAst.Fun buildMetadataFunction(Element element) {
if (!backend.retainMetadataOf(element)) return null;
return compiler.withCurrentElement(element, () {
var metadata = [];
Link link = element.metadata;
// TODO(ahe): Why is metadata sometimes null?
if (link != null) {
for (; !link.isEmpty; link = link.tail) {
MetadataAnnotation annotation = link.head;
Constant value = annotation.value;
if (value == null) {
compiler.reportInternalError(
annotation, 'Internal error: value is null');
} else {
metadata.add(constantReference(value));
}
}
}
if (metadata.isEmpty) return null;
return js.fun(
[], [js.return_(new jsAst.ArrayInitializer.from(metadata))]);
});
}
jsAst.Node reifyDefaultArguments(FunctionElement function) {
FunctionSignature signature = function.computeSignature(compiler);
if (signature.optionalParameterCount == 0) return null;
List<int> defaultValues = <int>[];
for (Element element in signature.orderedOptionalParameters) {
Constant value =
compiler.constantHandler.initialVariableValues[element];
String stringRepresentation = (value == null) ? "null"
: jsAst.prettyPrint(constantReference(value), compiler).getText();
defaultValues.add(addGlobalMetadata(stringRepresentation));
}
return js.toExpression(defaultValues);
}
int reifyMetadata(MetadataAnnotation annotation) {
Constant value = annotation.value;
if (value == null) {
compiler.reportInternalError(
annotation, 'Internal error: value is null');
return -1;
}
return addGlobalMetadata(
jsAst.prettyPrint(constantReference(value), compiler).getText());
}
int reifyType(DartType type) {
// TODO(ahe): Handle type variables correctly instead of using "#".
String representation = backend.rti.getTypeRepresentation(type, (_) {});
return addGlobalMetadata(representation.replaceAll('#', 'null'));
}
int reifyName(SourceString name) {
return addGlobalMetadata('"${name.slowToString()}"');
}
int addGlobalMetadata(String string) {
return globalMetadataMap.putIfAbsent(string, () {
globalMetadata.add(string);
return globalMetadata.length - 1;
});
}
jsAst.Fun extendWithMetadata(FunctionElement element, jsAst.Fun code) {
if (!backend.retainMetadataOf(element)) return code;
return compiler.withCurrentElement(element, () {
List<int> metadata = <int>[];
FunctionSignature signature = element.functionSignature;
if (element.isConstructor()) {
metadata.add(reifyType(element.getEnclosingClass().thisType));
} else {
metadata.add(reifyType(signature.returnType));
}
signature.forEachParameter((Element parameter) {
metadata
..add(reifyName(parameter.name))
..add(reifyType(parameter.computeType(compiler)));
});
Link link = element.metadata;
// TODO(ahe): Why is metadata sometimes null?
if (link != null) {
for (; !link.isEmpty; link = link.tail) {
metadata.add(reifyMetadata(link.head));
}
}
code.body.statements.add(js.string(metadata.join(',')).toStatement());
return code;
});
}
void emitMetadata(CodeBuffer buffer) {
var literals = backend.typedefTypeLiterals.toList();
Elements.sortedByPosition(literals);
var properties = [];
for (TypedefElement literal in literals) {
var key = namer.getNameX(literal);
var value = js.toExpression(reifyType(literal.rawType));
properties.add(new jsAst.Property(js.string(key), value));
}
var map = new jsAst.ObjectInitializer(properties);
buffer.write(
jsAst.prettyPrint(
js('init.functionAliases = #', map).toStatement(), compiler));
buffer.write('${N}init.metadata$_=$_[');
for (var metadata in globalMetadata) {
if (metadata is String) {
if (metadata != 'null') {
buffer.write(metadata);
}
} else {
throw 'Unexpected value in metadata: ${Error.safeToString(metadata)}';
}
buffer.write(',$n');
}
buffer.write('];$n');
}
void emitConvertToFastObjectFunction() {
// Create an instance that uses 'properties' as prototype. This should make
// 'properties' a fast object.
mainBuffer.add(r'''function convertToFastObject(properties) {
function MyClass() {};
MyClass.prototype = properties;
new MyClass();
''');
if (DEBUG_FAST_OBJECTS) {
ClassElement primitives =
compiler.findHelper(const SourceString('Primitives'));
FunctionElement printHelper =
compiler.lookupElementIn(
primitives, const SourceString('printString'));
String printHelperName = namer.isolateAccess(printHelper);
mainBuffer.add('''
// The following only works on V8 when run with option "--allow-natives-syntax".
if (typeof $printHelperName === "function") {
$printHelperName("Size of global object: "
+ String(Object.getOwnPropertyNames(properties).length)
+ ", fast properties " + %HasFastProperties(properties));
}
''');
}
mainBuffer.add(r'''
return properties;
}
''');
}
String assembleProgram() {
measure(() {
// Compute the required type checks to know which classes need a
// 'is$' method.
computeRequiredTypeChecks();
computeNeededClasses();
mainBuffer.add(buildGeneratedBy());
addComment(HOOKS_API_USAGE, mainBuffer);
if (!areAnyElementsDeferred) {
mainBuffer.add('(function(${namer.CURRENT_ISOLATE})$_{$n');
}
for (String globalObject in Namer.reservedGlobalObjectNames) {
// The global objects start as so-called "slow objects". For V8, this
// means that it won't try to make map transitions as we add properties
// to these objects. Later on, we attempt to turn these objects into
// fast objects by calling "convertToFastObject" (see
// [emitConvertToFastObjectFunction]).
mainBuffer
..write('var ${globalObject}$_=$_{}$N')
..write('delete ${globalObject}.x$N');
}
mainBuffer.add('function ${namer.isolateName}()$_{}\n');
mainBuffer.add('init()$N$n');
// Shorten the code by using [namer.CURRENT_ISOLATE] as temporary.
isolateProperties = namer.CURRENT_ISOLATE;
mainBuffer.add(
'$isolateProperties$_=$_$isolatePropertiesName$N');
emitStaticFunctions(mainBuffer);
if (!regularClasses.isEmpty ||
!deferredClasses.isEmpty ||
!nativeClasses.isEmpty ||
!compiler.codegenWorld.staticFunctionsNeedingGetter.isEmpty) {
// Shorten the code by using "$$" as temporary.
classesCollector = r"$$";
mainBuffer.add('var $classesCollector$_=$_{}$N$n');
}
// As a side-effect, emitting classes will produce "bound closures" in
// [methodClosures]. The bound closures are JS AST nodes that add
// properties to $$ [classesCollector]. The bound closures are not
// emitted until we have emitted all other classes (native or not).
// Might create methodClosures.
if (!regularClasses.isEmpty) {
for (ClassElement element in regularClasses) {
generateClass(element, bufferForElement(element, mainBuffer));
}
}
// Emit native classes on [nativeBuffer].
// Might create methodClosures.
final CodeBuffer nativeBuffer = new CodeBuffer();
if (!nativeClasses.isEmpty) {
addComment('Native classes', nativeBuffer);
addComment('Native classes', mainBuffer);
nativeEmitter.generateNativeClasses(nativeClasses, mainBuffer);
}
nativeEmitter.finishGenerateNativeClasses();
nativeEmitter.assembleCode(nativeBuffer);
// Might create methodClosures.
if (!deferredClasses.isEmpty) {
for (ClassElement element in deferredClasses) {
generateClass(element, bufferForElement(element, mainBuffer));
}
}
containerBuilder.emitStaticFunctionClosures();
addComment('Method closures', mainBuffer);
// Now that we have emitted all classes, we know all the method
// closures that will be needed.
containerBuilder.methodClosures.forEach((String code, Element closure) {
// TODO(ahe): Some of these can be deferred.
String mangledName = namer.getNameOfClass(closure);
mainBuffer.add('$classesCollector.$mangledName$_=$_'
'[${namer.globalObjectFor(closure)},$_$code]');
mainBuffer.add("$N$n");
});
// After this assignment we will produce invalid JavaScript code if we use
// the classesCollector variable.
classesCollector = 'classesCollector should not be used from now on';
if (!elementBuffers.isEmpty) {
var oldClassesCollector = classesCollector;
classesCollector = r"$$";
if (compiler.enableMinification) {
mainBuffer.write(';');
}
for (Element element in elementBuffers.keys) {
// TODO(ahe): Should iterate over all libraries. Otherwise, we will
// not see libraries that only have fields.
if (element.isLibrary()) {
LibraryElement library = element;
ClassBuilder builder = new ClassBuilder();
if (emitFields(library, builder, null, emitStatics: true)) {
List<CodeBuffer> buffers = elementBuffers[library];
var buffer = buffers[0];
if (buffer == null) {
buffers[0] = buffer = new CodeBuffer();
}
for (jsAst.Property property in builder.properties) {
if (!buffer.isEmpty) buffer.write(',$n');
buffer.addBuffer(jsAst.prettyPrint(property, compiler));
}
}
}
}
if (!mangledFieldNames.isEmpty) {
var keys = mangledFieldNames.keys.toList();
keys.sort();
var properties = [];
for (String key in keys) {
var value = js.string('${mangledFieldNames[key]}');
properties.add(new jsAst.Property(js.string(key), value));
}
var map = new jsAst.ObjectInitializer(properties);
mainBuffer.write(
jsAst.prettyPrint(
js('init.mangledNames = #', map).toStatement(), compiler));
if (compiler.enableMinification) {
mainBuffer.write(';');
}
}
if (!mangledGlobalFieldNames.isEmpty) {
var keys = mangledGlobalFieldNames.keys.toList();
keys.sort();
var properties = [];
for (String key in keys) {
var value = js.string('${mangledGlobalFieldNames[key]}');
properties.add(new jsAst.Property(js.string(key), value));
}
var map = new jsAst.ObjectInitializer(properties);
mainBuffer.write(
jsAst.prettyPrint(
js('init.mangledGlobalNames = #', map).toStatement(),
compiler));
if (compiler.enableMinification) {
mainBuffer.write(';');
}
}
mainBuffer
..write(getReflectionDataParser(classesCollector, namer))
..write('([$n');
List<Element> sortedElements =
Elements.sortedByPosition(elementBuffers.keys);
bool hasPendingStatics = false;
for (Element element in sortedElements) {
if (!element.isLibrary()) {
for (CodeBuffer b in elementBuffers[element]) {
if (b != null) {
hasPendingStatics = true;
compiler.reportInfo(
element, MessageKind.GENERIC, {'text': 'Pending statics.'});
print(b.getText());
}
}
continue;
}
LibraryElement library = element;
List<CodeBuffer> buffers = elementBuffers[library];
var buffer = buffers[0];
var uri = library.canonicalUri;
if (uri.scheme == 'file' && compiler.sourceMapUri != null) {
// TODO(ahe): It is a hack to use compiler.sourceMapUri
// here. It should be relative to the main JavaScript
// output file.
uri = relativize(
compiler.sourceMapUri, library.canonicalUri, false);
}
if (buffer != null) {
var metadata = buildMetadataFunction(library);
mainBuffer
..write('["${library.getLibraryOrScriptName()}",$_')
..write('"${uri}",$_')
..write(metadata == null
? "" : jsAst.prettyPrint(metadata, compiler))
..write(',$_')
..write(namer.globalObjectFor(library))
..write(',$_')
..write('{$n')
..addBuffer(buffer)
..write('}');
if (library == compiler.mainApp) {
mainBuffer.write(',${n}1');
}
mainBuffer.write('],$n');
}
buffer = buffers[1];
if (buffer != null) {
deferredLibraries
..write('["${library.getLibraryOrScriptName()}",$_')
..write('"${uri}",$_')
..write('[],$_')
..write(namer.globalObjectFor(library))
..write(',$_')
..write('{$n')
..addBuffer(buffer)
..write('}],$n');
}
elementBuffers[library] = const [];
}
if (hasPendingStatics) {
compiler.internalError('Pending statics (see above).');
}
mainBuffer.write('])$N');
emitFinishClassesInvocationIfNecessary(mainBuffer);
classesCollector = oldClassesCollector;
}
containerBuilder.emitStaticFunctionGetters(mainBuffer);
emitRuntimeTypeSupport(mainBuffer);
emitGetInterceptorMethods(mainBuffer);
// Constants in checked mode call into RTI code to set type information
// which may need getInterceptor methods, so we have to make sure that
// [emitGetInterceptorMethods] has been called.
emitCompileTimeConstants(mainBuffer);
// Static field initializations require the classes and compile-time
// constants to be set up.
emitStaticNonFinalFieldInitializations(mainBuffer);
emitOneShotInterceptors(mainBuffer);
emitInterceptedNames(mainBuffer);
emitMapTypeToInterceptor(mainBuffer);
emitLazilyInitializedStaticFields(mainBuffer);
mainBuffer.add(nativeBuffer);
emitMetadata(mainBuffer);
isolateProperties = isolatePropertiesName;
// The following code should not use the short-hand for the
// initialStatics.
mainBuffer.add('${namer.CURRENT_ISOLATE}$_=${_}null$N');
emitFinishIsolateConstructorInvocation(mainBuffer);
mainBuffer.add(
'${namer.CURRENT_ISOLATE}$_=${_}new ${namer.isolateName}()$N');
emitConvertToFastObjectFunction();
for (String globalObject in Namer.reservedGlobalObjectNames) {
mainBuffer.add('$globalObject = convertToFastObject($globalObject)$N');
}
if (DEBUG_FAST_OBJECTS) {
ClassElement primitives =
compiler.findHelper(const SourceString('Primitives'));
FunctionElement printHelper =
compiler.lookupElementIn(
primitives, const SourceString('printString'));
String printHelperName = namer.isolateAccess(printHelper);
mainBuffer.add('''
// The following only works on V8 when run with option "--allow-natives-syntax".
if (typeof $printHelperName === "function") {
$printHelperName("Size of global helper object: "
+ String(Object.getOwnPropertyNames(H).length)
+ ", fast properties " + %HasFastProperties(H));
$printHelperName("Size of global platform object: "
+ String(Object.getOwnPropertyNames(P).length)
+ ", fast properties " + %HasFastProperties(P));
$printHelperName("Size of global dart:html object: "
+ String(Object.getOwnPropertyNames(W).length)
+ ", fast properties " + %HasFastProperties(W));
$printHelperName("Size of isolate properties object: "
+ String(Object.getOwnPropertyNames(\$).length)
+ ", fast properties " + %HasFastProperties(\$));
$printHelperName("Size of constant object: "
+ String(Object.getOwnPropertyNames(C).length)
+ ", fast properties " + %HasFastProperties(C));
var names = Object.getOwnPropertyNames(\$);
for (var i = 0; i < names.length; i++) {
$printHelperName("\$." + names[i]);
}
}
''');
for (String object in Namer.userGlobalObjects) {
mainBuffer.add('''
if (typeof $printHelperName === "function") {
$printHelperName("Size of $object: "
+ String(Object.getOwnPropertyNames($object).length)
+ ", fast properties " + %HasFastProperties($object));
}
''');
}
}
emitMain(mainBuffer);
jsAst.FunctionDeclaration precompiledFunctionAst =
buildPrecompiledFunction();
emitInitFunction(mainBuffer);
if (!areAnyElementsDeferred) {
mainBuffer.add('})()\n');
} else {
mainBuffer.add('\n');
}
compiler.assembledCode = mainBuffer.getText();
outputSourceMap(compiler.assembledCode, '');
mainBuffer.write(
jsAst.prettyPrint(
precompiledFunctionAst, compiler,
allowVariableMinification: false).getText());
compiler.outputProvider('', 'precompiled.js')
..add(mainBuffer.getText())
..close();
emitDeferredCode();
});
return compiler.assembledCode;
}
CodeBuffer bufferForElement(Element element, CodeBuffer eagerBuffer) {
Element owner = element.getLibrary();
if (!element.isTopLevel() && !element.isNative()) {
// For static (not top level) elements, record their code in a buffer
// specific to the class. For now, not supported for native classes and
// native elements.
ClassElement cls =
element.getEnclosingClassOrCompilationUnit().declaration;
if (compiler.codegenWorld.instantiatedClasses.contains(cls)
&& !cls.isNative()) {
owner = cls;
}
}
if (owner == null) {
compiler.internalErrorOnElement(element, 'Owner is null');
}
List<CodeBuffer> buffers = elementBuffers.putIfAbsent(
owner, () => <CodeBuffer>[null, null]);
bool deferred = isDeferred(element);
int index = deferred ? 1 : 0;
CodeBuffer buffer = buffers[index];
if (buffer == null) {
buffer = buffers[index] = new CodeBuffer();
}
return buffer;
}
/**
* Returns the appropriate buffer for [constant]. If [constant] is
* itself an instance of a deferred type (or built from constants
* that are instances of deferred types) attempting to use
* [constant] before the deferred type has been loaded will not
* work, and [constant] itself must be deferred.
*/
CodeBuffer bufferForConstant(Constant constant, CodeBuffer eagerBuffer) {
var queue = new Queue()..add(constant);
while (!queue.isEmpty) {
constant = queue.removeFirst();
if (isDeferred(constant.computeType(compiler).element)) {
return deferredConstants;
}
queue.addAll(constant.getDependencies());
}
return eagerBuffer;
}
void emitDeferredCode() {
if (deferredLibraries.isEmpty && deferredConstants.isEmpty) return;
var oldClassesCollector = classesCollector;
classesCollector = r"$$";
// It does not make sense to defer constants if there are no
// deferred elements.
assert(!deferredLibraries.isEmpty);
var buffer = new CodeBuffer()
..write(buildGeneratedBy())
..write('var old${namer.CURRENT_ISOLATE}$_='
'$_${namer.CURRENT_ISOLATE}$N'
// TODO(ahe): This defines a lot of properties on the
// Isolate.prototype object. We know this will turn it into a
// slow object in V8, so instead we should do something similar
// to Isolate.$finishIsolateConstructor.
'${namer.CURRENT_ISOLATE}$_='
'$_${namer.isolateName}.prototype$N$n'
// The classesCollector object ($$).
'$classesCollector$_=$_{};$n')
..write(getReflectionDataParser(classesCollector, namer))
..write('([$n')
..addBuffer(deferredLibraries)
..write('])$N');
if (!deferredClasses.isEmpty) {
buffer.write(
'$finishClassesName($classesCollector,$_${namer.CURRENT_ISOLATE},'
'$_$isolatePropertiesName)$N');
}
buffer.write(
// Reset the classesCollector ($$).
'$classesCollector$_=${_}null$N$n'
'${namer.CURRENT_ISOLATE}$_=${_}old${namer.CURRENT_ISOLATE}$N');
classesCollector = oldClassesCollector;
if (!deferredConstants.isEmpty) {
buffer.addBuffer(deferredConstants);
}
String code = buffer.getText();
compiler.outputProvider('part', 'js')
..add(code)
..close();
outputSourceMap(compiler.assembledCode, 'part');
}
String buildGeneratedBy() {
var suffix = '';
if (compiler.hasBuildId) suffix = ' version: ${compiler.buildId}';
return '// Generated by dart2js, the Dart to JavaScript compiler$suffix.\n';
}
String buildSourceMap(CodeBuffer buffer, SourceFile compiledFile) {
SourceMapBuilder sourceMapBuilder =
new SourceMapBuilder(compiler.sourceMapUri);
buffer.forEachSourceLocation(sourceMapBuilder.addMapping);
return sourceMapBuilder.build(compiledFile);
}
void outputSourceMap(String code, String name) {
if (!generateSourceMap) return;
SourceFile compiledFile = new SourceFile(null, compiler.assembledCode);
String sourceMap = buildSourceMap(mainBuffer, compiledFile);
compiler.outputProvider(name, 'js.map')
..add(sourceMap)
..close();
}
bool isDeferred(Element element) {
return compiler.deferredLoadTask.isDeferred(element);
}
bool get areAnyElementsDeferred {
return compiler.deferredLoadTask.areAnyElementsDeferred;
}
}