| // Copyright (c) 2022, 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. |
| |
| import 'dart:collection'; |
| import 'dart:math' show max; |
| |
| import 'package:kernel/ast.dart'; |
| import 'package:kernel/core_types.dart'; |
| import 'package:kernel/type_environment.dart' as type_env; |
| import 'package:wasm_builder/wasm_builder.dart' as w; |
| |
| import 'class_info.dart'; |
| import 'code_generator.dart'; |
| import 'translator.dart'; |
| |
| /// Values for the `_kind` field in `_TopType`. Must match the definitions in |
| /// `_TopType`. |
| class TopTypeKind { |
| static const int objectKind = 0; |
| static const int dynamicKind = 1; |
| static const int voidKind = 2; |
| } |
| |
| class InterfaceTypeEnvironment { |
| final Map<TypeParameter, int> _typeOffsets = {}; |
| |
| void _add(InterfaceType type) { |
| Class cls = type.classNode; |
| int i = 0; |
| for (TypeParameter typeParameter in cls.typeParameters) { |
| _typeOffsets[typeParameter] = i++; |
| } |
| } |
| |
| int lookup(TypeParameter typeParameter) => _typeOffsets[typeParameter]!; |
| } |
| |
| /// Helper class for building runtime types. |
| class Types { |
| final Translator translator; |
| |
| /// Class info for `_Type` |
| late final ClassInfo typeClassInfo = |
| translator.classInfo[translator.typeClass]!; |
| |
| /// Wasm value type of `List<_Type>` |
| late final w.ValueType typeListExpectedType = |
| translator.classInfo[translator.listBaseClass]!.nonNullableType; |
| |
| /// Wasm array type of `WasmArray<_Type>` |
| late final w.ArrayType typeArrayArrayType = |
| translator.arrayTypeForDartType(typeType); |
| |
| /// Wasm value type of `WasmArray<_Type>` |
| late final w.ValueType typeArrayExpectedType = |
| w.RefType.def(typeArrayArrayType, nullable: false); |
| |
| /// Wasm value type of `WasmArray<_NamedParameter>` |
| late final w.ValueType namedParametersExpectedType = classAndFieldToType( |
| translator.functionTypeClass, FieldIndex.functionTypeNamedParameters); |
| |
| /// Wasm value type of `_RecordType.names` field. |
| late final w.ValueType recordTypeNamesFieldExpectedType = classAndFieldToType( |
| translator.recordTypeClass, FieldIndex.recordTypeNames); |
| |
| late final RuntimeTypeInformation rtt = RuntimeTypeInformation(translator); |
| |
| /// We will build the [interfaceTypeEnvironment] when building the |
| /// [typeRules]. |
| final InterfaceTypeEnvironment interfaceTypeEnvironment = |
| InterfaceTypeEnvironment(); |
| |
| /// Type parameter offset for function types, specifying the lower end of |
| /// their index range for type parameter types. |
| Map<FunctionType, int> functionTypeParameterOffset = Map.identity(); |
| |
| /// Index value for function type parameter types, indexing into the type |
| /// parameter index range of their corresponding function type. |
| Map<StructuralParameter, int> functionTypeParameterIndex = Map.identity(); |
| |
| Types(this.translator); |
| |
| w.ValueType classAndFieldToType(Class cls, int fieldIndex) => |
| translator.classInfo[cls]!.struct.fields[fieldIndex].type.unpacked; |
| |
| /// Wasm value type for non-nullable `_Type` values |
| w.ValueType get nonNullableTypeType => typeClassInfo.nonNullableType; |
| |
| InterfaceType get namedParameterType => |
| InterfaceType(translator.namedParameterClass, Nullability.nonNullable); |
| |
| InterfaceType get typeType => |
| InterfaceType(translator.typeClass, Nullability.nonNullable); |
| |
| CoreTypes get coreTypes => translator.coreTypes; |
| |
| bool isTypeConstant(DartType type) { |
| return type is DynamicType || |
| type is VoidType || |
| type is NeverType || |
| type is NullType || |
| type is FutureOrType && isTypeConstant(type.typeArgument) || |
| (type is FunctionType && |
| type.typeParameters.every((p) => isTypeConstant(p.bound)) && |
| isTypeConstant(type.returnType) && |
| type.positionalParameters.every(isTypeConstant) && |
| type.namedParameters.every((n) => isTypeConstant(n.type))) || |
| type is InterfaceType && type.typeArguments.every(isTypeConstant) || |
| (type is RecordType && |
| type.positional.every(isTypeConstant) && |
| type.named.every((n) => isTypeConstant(n.type))) || |
| type is StructuralParameterType || |
| type is ExtensionType && isTypeConstant(type.extensionTypeErasure); |
| } |
| |
| Class classForType(DartType type) { |
| if (type is DynamicType) { |
| return translator.topTypeClass; |
| } else if (type is VoidType) { |
| return translator.topTypeClass; |
| } else if (type is NeverType) { |
| return translator.bottomTypeClass; |
| } else if (type is NullType) { |
| return translator.bottomTypeClass; |
| } else if (type is FutureOrType) { |
| return translator.futureOrTypeClass; |
| } else if (type is InterfaceType) { |
| if (type.classNode == coreTypes.objectClass) { |
| return translator.topTypeClass; |
| } |
| if (type.classNode == coreTypes.functionClass) { |
| return translator.abstractFunctionTypeClass; |
| } |
| if (type.classNode == coreTypes.recordClass) { |
| return translator.abstractRecordTypeClass; |
| } |
| return translator.interfaceTypeClass; |
| } else if (type is FunctionType) { |
| return translator.functionTypeClass; |
| } else if (type is TypeParameterType) { |
| return translator.interfaceTypeParameterTypeClass; |
| } else if (type is StructuralParameterType) { |
| return translator.functionTypeParameterTypeClass; |
| } else if (type is ExtensionType) { |
| return classForType(type.extensionTypeErasure); |
| } else if (type is RecordType) { |
| return translator.recordTypeClass; |
| } |
| throw "Unexpected DartType: $type"; |
| } |
| |
| bool isSpecializedClass(Class cls) { |
| return cls == coreTypes.objectClass || |
| cls == coreTypes.functionClass || |
| cls == coreTypes.recordClass; |
| } |
| |
| int topTypeKind(DartType type) { |
| return type is VoidType |
| ? TopTypeKind.voidKind |
| : type is DynamicType |
| ? TopTypeKind.dynamicKind |
| : TopTypeKind.objectKind; |
| } |
| |
| /// Allocates a `WasmArray<_Type>` from [types] and pushes it to the |
| /// stack. |
| void _makeTypeArray(CodeGenerator codeGen, Iterable<DartType> types) { |
| if (types.every(isTypeConstant)) { |
| translator.constants.instantiateConstant(codeGen.function, codeGen.b, |
| translator.constants.makeTypeArray(types), typeArrayExpectedType); |
| } else { |
| for (DartType type in types) { |
| makeType(codeGen, type); |
| } |
| codeGen.b.array_new_fixed(typeArrayArrayType, types.length); |
| } |
| } |
| |
| void _makeInterfaceType(CodeGenerator codeGen, InterfaceType type) { |
| final b = codeGen.b; |
| ClassInfo typeInfo = translator.classInfo[type.classNode]!; |
| b.i32_const(encodedNullability(type)); |
| b.i64_const(typeInfo.classId); |
| _makeTypeArray(codeGen, type.typeArguments); |
| } |
| |
| void _makeRecordType(CodeGenerator codeGen, RecordType type) { |
| codeGen.b.i32_const(encodedNullability(type)); |
| |
| final names = translator.constants.makeArrayOf( |
| translator.coreTypes.stringNonNullableRawType, |
| type.named.map((t) => StringConstant(t.name)).toList()); |
| |
| translator.constants.instantiateConstant( |
| codeGen.function, codeGen.b, names, recordTypeNamesFieldExpectedType); |
| _makeTypeArray( |
| codeGen, type.positional.followedBy(type.named.map((t) => t.type))); |
| } |
| |
| /// Normalizes a Dart type. Many rules are already applied for us, but we |
| /// still have to manually turn `Never?` into `Null` and normalize `FutureOr`. |
| DartType normalize(DartType type) { |
| if (type is NeverType && type.declaredNullability == Nullability.nullable) { |
| return const NullType(); |
| } |
| |
| if (type is! FutureOrType) return type; |
| |
| final s = normalize(type.typeArgument); |
| |
| // `coreTypes.isTop` and `coreTypes.isObject` take into account the |
| // normalization rules of `FutureOr`. |
| if (coreTypes.isTop(type) || coreTypes.isObject(type)) { |
| return type.declaredNullability == Nullability.nullable |
| ? s.withDeclaredNullability(Nullability.nullable) |
| : s; |
| } else if (s is NeverType) { |
| return InterfaceType(coreTypes.futureClass, Nullability.nonNullable, |
| const [NeverType.nonNullable()]); |
| } else if (s is NullType) { |
| return InterfaceType( |
| coreTypes.futureClass, Nullability.nullable, const [NullType()]); |
| } |
| |
| // The type is normalized, and remains a `FutureOr` so now we normalize its |
| // nullability. |
| // Note: We diverge from the spec here and normalize the type to nullable if |
| // its type argument is nullable, since this simplifies subtype checking. |
| // We compensate for this difference when converting the type to a string, |
| // making the discrepancy invisible to the user. |
| final declaredNullability = s.nullability == Nullability.nullable |
| ? Nullability.nullable |
| : type.declaredNullability; |
| return FutureOrType(s, declaredNullability); |
| } |
| |
| void _makeFutureOrType(CodeGenerator codeGen, FutureOrType type) { |
| final b = codeGen.b; |
| b.i32_const(encodedNullability(type)); |
| makeType(codeGen, type.typeArgument); |
| codeGen.call(translator.createNormalizedFutureOrType.reference); |
| } |
| |
| void _makeFunctionType(CodeGenerator codeGen, FunctionType type) { |
| int typeParameterOffset = computeFunctionTypeParameterOffset(type); |
| final b = codeGen.b; |
| b.i32_const(encodedNullability(type)); |
| b.i64_const(typeParameterOffset); |
| |
| // WasmArray<_Type> typeParameterBounds |
| _makeTypeArray(codeGen, type.typeParameters.map((p) => p.bound)); |
| |
| // WasmArray<_Type> typeParameterDefaults |
| _makeTypeArray(codeGen, type.typeParameters.map((p) => p.defaultType)); |
| |
| // _Type returnType |
| makeType(codeGen, type.returnType); |
| |
| // WasmArray<_Type> positionalParameters |
| _makeTypeArray(codeGen, type.positionalParameters); |
| |
| // int requiredParameterCount |
| b.i64_const(type.requiredParameterCount); |
| |
| // WasmArray<_NamedParameter> namedParameters |
| if (type.namedParameters.every((n) => isTypeConstant(n.type))) { |
| translator.constants.instantiateConstant( |
| codeGen.function, |
| b, |
| translator.constants.makeNamedParametersArray(type), |
| namedParametersExpectedType); |
| } else { |
| Class namedParameterClass = translator.namedParameterClass; |
| Constructor namedParameterConstructor = |
| namedParameterClass.constructors.single; |
| List<Expression> expressions = []; |
| for (NamedType n in type.namedParameters) { |
| expressions.add(isTypeConstant(n.type) |
| ? ConstantExpression( |
| translator.constants.makeNamedParameterConstant(n), |
| namedParameterType) |
| : ConstructorInvocation( |
| namedParameterConstructor, |
| Arguments([ |
| StringLiteral(n.name), |
| TypeLiteral(n.type), |
| BoolLiteral(n.isRequired) |
| ]))); |
| } |
| w.ValueType namedParametersListType = |
| codeGen.makeArrayFromExpressions(expressions, namedParameterType); |
| translator.convertType(codeGen.function, namedParametersListType, |
| namedParametersExpectedType); |
| } |
| } |
| |
| /// Makes a `_Type` object on the stack. |
| /// TODO(joshualitt): Refactor this logic to remove the dependency on |
| /// CodeGenerator. |
| w.ValueType makeType(CodeGenerator codeGen, DartType type) { |
| // Always ensure type is normalized before making a type. |
| type = normalize(type); |
| final b = codeGen.b; |
| if (isTypeConstant(type)) { |
| translator.constants.instantiateConstant( |
| codeGen.function, b, TypeLiteralConstant(type), nonNullableTypeType); |
| return nonNullableTypeType; |
| } |
| // All of the singleton types represented by canonical objects should be |
| // created const. |
| assert(type is TypeParameterType || |
| type is ExtensionType || |
| type is InterfaceType || |
| type is FutureOrType || |
| type is FunctionType || |
| type is RecordType); |
| if (type is TypeParameterType) { |
| codeGen.instantiateTypeParameter(type.parameter); |
| if (type.declaredNullability == Nullability.nullable) { |
| codeGen.call(translator.typeAsNullable.reference); |
| } |
| return nonNullableTypeType; |
| } |
| |
| if (type is ExtensionType) { |
| return makeType(codeGen, type.extensionTypeErasure); |
| } |
| |
| ClassInfo info = translator.classInfo[classForType(type)]!; |
| if (type is FutureOrType) { |
| _makeFutureOrType(codeGen, type); |
| return info.nonNullableType; |
| } |
| |
| translator.functions.recordClassAllocation(info.classId); |
| b.i32_const(info.classId); |
| b.i32_const(initialIdentityHash); |
| if (type is InterfaceType) { |
| _makeInterfaceType(codeGen, type); |
| } else if (type is FunctionType) { |
| _makeFunctionType(codeGen, type); |
| } else if (type is RecordType) { |
| _makeRecordType(codeGen, type); |
| } else { |
| throw '`$type` should have already been handled.'; |
| } |
| b.struct_new(info.struct); |
| return info.nonNullableType; |
| } |
| |
| /// Compute the lower end of the type parameter index range for this function |
| /// type. This is computed such that it avoids overlap between the index range |
| /// of this function type and the index ranges of all generic function types |
| /// nested within it that contain references to the type parameters of this |
| /// function type. |
| /// |
| /// This will also compute the index values for all of the function's type |
| /// parameters, which can subsequently be queried using |
| /// [getFunctionTypeParameterIndex]. |
| int computeFunctionTypeParameterOffset(FunctionType type) { |
| if (type.typeParameters.isEmpty) return 0; |
| int? offset = functionTypeParameterOffset[type]; |
| if (offset != null) return offset; |
| _FunctionTypeParameterOffsetCollector(this).visitFunctionType(type); |
| return functionTypeParameterOffset[type]!; |
| } |
| |
| /// Get the index value for a function type parameter, indexing into the |
| /// type parameter index range of its corresponding function type. |
| int getFunctionTypeParameterIndex(StructuralParameter type) { |
| assert(functionTypeParameterIndex.containsKey(type), |
| "Type parameter offset has not been computed for function type"); |
| return functionTypeParameterIndex[type]!; |
| } |
| |
| /// Emit code for testing a value against a Dart type. Expects the value on |
| /// the stack as a (ref null #Top) and leaves the result on the stack as an |
| /// i32. |
| void emitIsTest( |
| CodeGenerator codeGen, DartType testedAgainstType, DartType operandType, |
| [Location? location]) { |
| final b = codeGen.b; |
| b.comment("type check against $testedAgainstType"); |
| w.Local? operandTemp; |
| if (translator.options.verifyTypeChecks) { |
| operandTemp = |
| b.addLocal(translator.topInfo.nullableType, isParameter: false); |
| b.local_tee(operandTemp); |
| } |
| final typeToCheck = _canUseTypeCheckHelper(testedAgainstType, operandType); |
| if (typeToCheck != null) { |
| b.call( |
| _generateIsChecker(typeToCheck, operandType.isPotentiallyNullable)); |
| } else { |
| makeType(codeGen, testedAgainstType); |
| codeGen.call(translator.isSubtype.reference); |
| } |
| if (translator.options.verifyTypeChecks) { |
| b.local_get(operandTemp!); |
| makeType(codeGen, testedAgainstType); |
| if (location != null) { |
| w.FunctionType verifyFunctionType = translator.functions |
| .getFunctionType(translator.verifyOptimizedTypeCheck.reference); |
| translator.constants.instantiateConstant(codeGen.function, b, |
| StringConstant('$location'), verifyFunctionType.inputs.last); |
| } else { |
| b.ref_null(w.HeapType.none); |
| } |
| codeGen.call(translator.verifyOptimizedTypeCheck.reference); |
| } |
| } |
| |
| w.ValueType emitAsCheck(CodeGenerator codeGen, DartType testedAgainstType, |
| DartType operandType, w.RefType boxedOperandType, |
| [Location? location]) { |
| final b = codeGen.b; |
| |
| final typeToCheck = _canUseTypeCheckHelper(testedAgainstType, operandType); |
| if (typeToCheck != null) { |
| b.call( |
| _generateAsChecker(typeToCheck, operandType.isPotentiallyNullable)); |
| return translator.translateType(testedAgainstType); |
| } |
| |
| w.Local operand = b.addLocal(boxedOperandType, isParameter: false); |
| b.local_tee(operand); |
| makeType(codeGen, testedAgainstType); |
| final outputs = codeGen.call(translator.asSubtype.reference); |
| for (final _ in outputs) { |
| b.drop(); |
| } |
| b.local_get(operand); |
| return operand.type; |
| } |
| |
| // Returns the type to check against if a helper can be used, otherwise `null` |
| InterfaceType? _canUseTypeCheckHelper( |
| DartType testedAgainstType, DartType operandType) { |
| // The is/as check helpers are for cid-range checks of interface types. |
| if (testedAgainstType is! InterfaceType || operandType is! InterfaceType) { |
| return null; |
| } |
| |
| if (_hasOnlyDefaultTypeArguments(testedAgainstType)) { |
| return testedAgainstType; |
| } |
| |
| if (_staticTypesEnsureTypeArgumentsMatch(testedAgainstType, operandType)) { |
| // We only need to check whether the nullability and the class itself fits |
| // (the [testedAgainstType] arguments are guaranteed to fit statically) |
| final parameters = testedAgainstType.classNode.typeParameters; |
| final args = [ |
| for (int i = 0; i < parameters.length; ++i) parameters[i].defaultType, |
| ]; |
| return InterfaceType( |
| testedAgainstType.classNode, testedAgainstType.nullability, args); |
| } |
| return null; |
| } |
| |
| bool _staticTypesEnsureTypeArgumentsMatch( |
| InterfaceType testedAgainstType, InterfaceType operandType) { |
| assert(testedAgainstType.typeArguments.isNotEmpty); |
| |
| // If the operand type doesn't have any type arguments it will not be able |
| // to tell us anything about the type arguments of testedAgainstType. |
| if (operandType.typeArguments.isEmpty) return false; |
| |
| final sufficiency = translator.typeEnvironment |
| .computeTypeShapeCheckSufficiency( |
| expressionStaticType: operandType, |
| checkTargetType: |
| testedAgainstType.withDeclaredNullability(Nullability.nullable), |
| subtypeCheckMode: type_env.SubtypeCheckMode.withNullabilities); |
| |
| // If `true` the caller only needs to check nullabillity and the actual |
| // concrete class, no need to check [testedAgainstType] arguments. |
| return sufficiency == type_env.TypeShapeCheckSufficiency.interfaceShape; |
| } |
| |
| bool _hasOnlyDefaultTypeArguments(InterfaceType testedAgainstType) { |
| if (testedAgainstType.typeArguments.isEmpty) return true; |
| |
| final parameters = testedAgainstType.classNode.typeParameters; |
| final arguments = testedAgainstType.typeArguments; |
| assert(parameters.length == arguments.length); |
| for (int i = 0; i < arguments.length; ++i) { |
| if (arguments[i] != parameters[i].defaultType) return false; |
| } |
| return true; |
| } |
| |
| final Map<DartType, w.BaseFunction> _nullableIsCheckers = {}; |
| final Map<DartType, w.BaseFunction> _isCheckers = {}; |
| |
| // Currently the is-checker helper functions only check nullability and the |
| // concrete class (the arguments do not have to be checked). |
| w.BaseFunction _generateIsChecker( |
| InterfaceType testedAgainstType, bool operandIsNullable) { |
| assert(_hasOnlyDefaultTypeArguments(testedAgainstType)); |
| |
| final interfaceClass = testedAgainstType.classNode; |
| |
| final cachedIsCheckers = |
| operandIsNullable ? _nullableIsCheckers : _isCheckers; |
| |
| return cachedIsCheckers.putIfAbsent(testedAgainstType, () { |
| final argumentType = operandIsNullable |
| ? translator.topInfo.nullableType |
| : translator.topInfo.nonNullableType; |
| final function = translator.m.functions.define( |
| translator.m.types.defineFunction( |
| [argumentType], |
| [w.NumType.i32], |
| ), |
| '<obj> is ${testedAgainstType.classNode}'); |
| |
| final b = function.body; |
| b.local_get(b.locals[0]); |
| |
| w.Label? resultLabel; |
| if (operandIsNullable) { |
| // Store operand in a temporary variable, since Binaryen does not support |
| // block inputs. |
| w.Local operand = function.addLocal(translator.topInfo.nullableType); |
| b.local_set(operand); |
| resultLabel = b.block(const [], const [w.NumType.i32]); |
| w.Label nullLabel = b.block(const [], const []); |
| b.local_get(operand); |
| b.br_on_null(nullLabel); |
| } |
| |
| if (interfaceClass == coreTypes.objectClass) { |
| b.drop(); |
| b.i32_const(1); |
| } else if (interfaceClass == coreTypes.functionClass) { |
| b.ref_test(translator.closureInfo.nonNullableType); |
| } else { |
| final ranges = translator.classIdNumbering |
| .getConcreteClassIdRanges(interfaceClass); |
| b.struct_get(translator.topInfo.struct, FieldIndex.classId); |
| b.emitClassIdRangeCheck(ranges); |
| } |
| |
| if (operandIsNullable) { |
| b.br(resultLabel!); |
| b.end(); // nullLabel |
| b.i32_const(encodedNullability(testedAgainstType)); |
| b.end(); // resultLabel |
| } |
| |
| b.return_(); |
| b.end(); |
| |
| return function; |
| }); |
| } |
| |
| final Map<DartType, w.BaseFunction> _nullableAsCheckers = {}; |
| final Map<DartType, w.BaseFunction> _asCheckers = {}; |
| |
| // Currently the as-checker helper functions only check nullability and the |
| // concrete class (the arguments do not have to be checked). |
| w.BaseFunction _generateAsChecker( |
| InterfaceType testedAgainstType, bool operandIsNullable) { |
| assert(_hasOnlyDefaultTypeArguments(testedAgainstType)); |
| |
| final cachedAsCheckers = |
| operandIsNullable ? _nullableAsCheckers : _asCheckers; |
| final returnType = translator.translateType(testedAgainstType); |
| return cachedAsCheckers.putIfAbsent(testedAgainstType, () { |
| final argumentType = operandIsNullable |
| ? translator.topInfo.nullableType |
| : translator.topInfo.nonNullableType; |
| final function = translator.m.functions.define( |
| translator.m.types.defineFunction( |
| [argumentType], |
| [returnType], |
| ), |
| '<obj> as ${testedAgainstType.classNode}'); |
| |
| final b = function.body; |
| w.Label asCheckBlock = b.block(); |
| b.local_get(b.locals[0]); |
| b.call(_generateIsChecker(testedAgainstType, operandIsNullable)); |
| b.br_if(asCheckBlock); |
| |
| b.local_get(b.locals[0]); |
| translator.constants.instantiateConstant(function, b, |
| TypeLiteralConstant(testedAgainstType), nonNullableTypeType); |
| b.call(translator.functions |
| .getFunction(translator.throwAsCheckError.reference)); |
| b.unreachable(); |
| |
| b.end(); |
| |
| b.local_get(b.locals[0]); |
| translator.convertType(function, argumentType, returnType); |
| b.return_(); |
| b.end(); |
| |
| return function; |
| }); |
| } |
| |
| int encodedNullability(DartType type) => |
| type.declaredNullability == Nullability.nullable ? 1 : 0; |
| } |
| |
| /// Builds up data structures that the Runtime Type System implementation uses. |
| /// |
| /// There are 3 data structures: |
| /// |
| /// * The name of all classes represented as an wasm array of strings. |
| /// |
| /// * A canonical substitution table where each entry represents |
| /// (potentially uninstantiated) type arguments to a superclass. |
| /// |
| /// => This is used for translating type arguments between related classes |
| /// in a hierarchy. |
| /// |
| /// * A table mapping each class id to its transitive super classes (i.e. |
| /// transitive implements/extends) and an index into the canonical |
| /// substitution table on how to translate type arguments between the two |
| /// related clases. |
| /// |
| /// See sdk/lib/_internal/wasm/lib/type.dart for more information. |
| class RuntimeTypeInformation { |
| final Translator translator; |
| |
| /// Canonical substitution table of type `const WasmArray<WasmArray<_Type>>`. |
| /// |
| /// Stores a canonical table of substitution arrays. Each substitution array |
| /// describes (possibly uninstantiated) type arguments that can be |
| /// instantiated with actual object type arguments. |
| /// => This allows translating an objects type arguments to the type arguments |
| /// of a related super class. |
| /// |
| /// See sdk/lib/_internal/wasm/lib/type.dart:_canonicalSubstitutionTable for |
| /// what this contains and how it's used for substitution. |
| late final InstanceConstant substitutionTableConstant; |
| |
| /// The Dart type of the [substitutionTableConstant] constant. |
| late final DartType substitutionTableConstantType; |
| |
| /// This index in the substitution canonicalization table indicates that we do |
| /// not have to substitute anything. |
| static const int noSubstitutionIndex = 0; |
| |
| /// Type rules supers table of type `const WasmArray<WasmArray<_WasmI32>>`. |
| /// |
| /// Has an array for every class id in the system. For a particular class id |
| /// it has (super-classId, canonical-substitutionIndex) tuples used by the RTT |
| /// system to determine whether two classes are related and how to translate |
| /// type arguments from one class to type arguments of a related other class. |
| /// |
| /// See sdk/lib/_internal/wasm/lib/type.dart:_typeRulesSupers for |
| /// what this contains and how it's used for substitution. |
| late final InstanceConstant typeRulesSupers; |
| late final DartType typeRulesSupersType; |
| |
| /// Table of type names indexed by class id. |
| late final InstanceConstant typeNames; |
| late final DartType typeNamesType; |
| |
| CoreTypes get coreTypes => translator.coreTypes; |
| Types get types => translator.types; |
| |
| RuntimeTypeInformation(this.translator) { |
| final ( |
| Map<int, Map<int, int>> typeRules, |
| LinkedHashMap<InstanceConstant, int> substitutionTable |
| ) = _buildTypeRules(); |
| |
| // The canonical substitution table of type WasmArray<WasmArray<_Type>> |
| _initSubstitutionTableConstant(substitutionTable); |
| |
| // The super type substitution rules for each class of type |
| // WasmArray<WasmArray<WasmI32>>. |
| _initTypeRulesSupers(typeRules); |
| |
| // The class name table of type WasmArray<String> |
| _initTypeNames(); |
| } |
| |
| (Map<int, Map<int, int>>, LinkedHashMap<InstanceConstant, int>) |
| _buildTypeRules() { |
| final subtypeMap = <int, Map<int, int>>{}; |
| // ignore: prefer_collection_literals |
| final substitutionTable = LinkedHashMap<InstanceConstant, int>(); |
| |
| assert(noSubstitutionIndex == 0); |
| assert(substitutionTable.length == noSubstitutionIndex); |
| substitutionTable[translator.constants.makeTypeArray([])] = |
| noSubstitutionIndex; |
| |
| for (ClassInfo classInfo in translator.classes) { |
| ClassInfo superclassInfo = classInfo; |
| |
| // We don't need type rules for any class without a superclass, or for |
| // classes whose supertype is [Object]. The latter case will be handled |
| // directly in the subtype checking algorithm. |
| if (superclassInfo.cls == null || |
| superclassInfo.cls == coreTypes.objectClass) { |
| continue; |
| } |
| Class superclass = superclassInfo.cls!; |
| |
| // TODO(joshualitt): This includes abstract types that can't be |
| // instantiated, but might be needed for subtype checks. The majority of |
| // abstract classes are probably unnecessary though. We should filter |
| // these cases to reduce the size of the type rules. |
| Iterable<Class> subclasses = translator.subtypes |
| .getSubtypesOf(superclass) |
| .where((cls) => cls != superclass); |
| Iterable<InterfaceType> subtypes = subclasses.map( |
| (Class cls) => cls.getThisType(coreTypes, Nullability.nonNullable)); |
| for (InterfaceType subtype in subtypes) { |
| types.interfaceTypeEnvironment._add(subtype); |
| |
| final List<DartType>? typeArguments = translator.hierarchy |
| .getInterfaceTypeArgumentsAsInstanceOfClass(subtype, superclass) |
| ?.map(types.normalize) |
| .toList(); |
| |
| int substitutionIndex; |
| if (_isIdentitySubstitution(typeArguments)) { |
| substitutionIndex = noSubstitutionIndex; |
| } else { |
| final substitution = |
| translator.constants.makeTypeArray(typeArguments!); |
| substitutionIndex = substitutionTable.putIfAbsent( |
| substitution, () => substitutionTable.length); |
| } |
| |
| final subclassId = translator.classInfo[subtype.classNode]!.classId; |
| (subtypeMap[subclassId] ??= {})[superclassInfo.classId] = |
| substitutionIndex; |
| } |
| } |
| return (subtypeMap, substitutionTable); |
| } |
| |
| /// Whether the substitution [typeArguments] would cause a NOP substitution. |
| /// |
| /// We have a NOP substitution if one of the following conditions apply: |
| /// |
| /// - the classes are unrelated |
| /// - the super class is not generic |
| /// - the type arguments from subclass are the same as for the super class |
| /// |
| bool _isIdentitySubstitution(List<DartType>? typeArguments) { |
| // This happen if the classes are not related to each other. |
| if (typeArguments == null) return true; |
| |
| for (int i = 0; i < typeArguments.length; ++i) { |
| final typeArgument = typeArguments[i]; |
| if (typeArgument is! TypeParameterType) { |
| return false; |
| } |
| if (typeArgument.declaredNullability == Nullability.nullable) { |
| return false; |
| } |
| final int environmentIndex = |
| types.interfaceTypeEnvironment.lookup(typeArgument.parameter); |
| if (i != environmentIndex) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| void _initSubstitutionTableConstant( |
| LinkedHashMap<InstanceConstant, int> substitutionTable) { |
| final typeType = |
| InterfaceType(translator.typeClass, Nullability.nonNullable); |
| final arrayOfType = InterfaceType( |
| translator.wasmArrayClass, Nullability.nonNullable, [typeType]); |
| |
| // We rely on the keys being in insertion order. |
| substitutionTableConstant = translator.constants |
| .makeArrayOf(arrayOfType, substitutionTable.keys.toList()); |
| substitutionTableConstantType = InterfaceType( |
| translator.wasmArrayClass, Nullability.nonNullable, [arrayOfType]); |
| } |
| |
| void _initTypeRulesSupers(Map<int, Map<int, int>> typeRules) { |
| final wasmI32 = |
| InterfaceType(translator.wasmI32Class, Nullability.nonNullable); |
| final arrayOfI32 = InterfaceType( |
| translator.wasmArrayClass, Nullability.nonNullable, [wasmI32]); |
| |
| // Maps each class id to a list of |
| // (implementedClassId, substitutionTableIndex) tuples. |
| final typeRulesArray = <InstanceConstant>[]; |
| for (int classId = 0; classId < translator.classes.length; classId++) { |
| final rules = typeRules[classId]; |
| if (rules == null) { |
| typeRulesArray.add( |
| translator.constants.makeArrayOf(wasmI32, const <IntConstant>[])); |
| continue; |
| } |
| |
| final List<int> superclassIds = rules.keys.toList(); |
| superclassIds.sort(); |
| final superClassSubstitutionTuples = |
| List<IntConstant>.filled(2 * superclassIds.length, IntConstant(0)); |
| for (int i = 0; i < superclassIds.length; ++i) { |
| final superClassId = superclassIds[i]; |
| final substitutionTableIndex = rules[superClassId]!; |
| |
| superClassSubstitutionTuples[2 * i + 0] = IntConstant(superClassId); |
| superClassSubstitutionTuples[2 * i + 1] = |
| IntConstant(substitutionTableIndex); |
| } |
| typeRulesArray.add(translator.constants |
| .makeArrayOf(wasmI32, superClassSubstitutionTuples)); |
| } |
| typeRulesSupers = |
| translator.constants.makeArrayOf(arrayOfI32, typeRulesArray); |
| typeRulesSupersType = InterfaceType( |
| translator.wasmArrayClass, Nullability.nonNullable, [arrayOfI32]); |
| } |
| |
| void _initTypeNames() { |
| final stringType = |
| translator.coreTypes.stringRawType(Nullability.nonNullable); |
| |
| final emptyString = StringConstant(''); |
| List<StringConstant> nameConstants = []; |
| for (ClassInfo classInfo in translator.classes) { |
| Class? cls = classInfo.cls; |
| if (cls == null || cls.isAnonymousMixin) { |
| nameConstants.add(emptyString); |
| } else { |
| nameConstants.add(StringConstant(cls.name)); |
| } |
| } |
| typeNames = translator.constants.makeArrayOf(stringType, nameConstants); |
| typeNamesType = InterfaceType( |
| translator.wasmArrayClass, Nullability.nonNullable, [stringType]); |
| } |
| } |
| |
| /// For a function type F = `... Function<X0, ..., Xn-1>(...)` compute offset(F) |
| /// such that for any function type G = `... Function<Y0, ..., Ym-1>(...)` |
| /// nested inside F, if G contains a reference to any type parameters of F, then |
| /// offset(F) >= offset(G) + m. |
| /// |
| /// Conceptually, the type parameters of F are indexed from offset(F) inclusive |
| /// to offset(F) + n exclusive. |
| /// |
| /// Also assign to each type parameter Xi the index offset(F) + i such that it |
| /// indexes the correct type parameter in the conceptual type parameter index |
| /// range of F. |
| /// |
| /// This ensures that for every reference to a type parameter, its corresponding |
| /// function type is the innermost function type enclosing it for which the |
| /// index falls within the type parameter index range of the function type. |
| class _FunctionTypeParameterOffsetCollector extends RecursiveVisitor { |
| final Types types; |
| |
| final List<FunctionType> _functionStack = []; |
| final List<Set<FunctionType>> _functionsContainingParameters = []; |
| final Map<StructuralParameter, int> _functionForParameter = {}; |
| |
| _FunctionTypeParameterOffsetCollector(this.types); |
| |
| @override |
| void visitFunctionType(FunctionType node) { |
| int slot = _functionStack.length; |
| _functionStack.add(node); |
| _functionsContainingParameters.add({}); |
| |
| for (int i = 0; i < node.typeParameters.length; i++) { |
| StructuralParameter parameter = node.typeParameters[i]; |
| _functionForParameter[parameter] = slot; |
| } |
| |
| super.visitFunctionType(node); |
| |
| int offset = 0; |
| for (FunctionType inner in _functionsContainingParameters.last) { |
| offset = max( |
| offset, |
| types.functionTypeParameterOffset[inner]! + |
| inner.typeParameters.length); |
| } |
| types.functionTypeParameterOffset[node] = offset; |
| |
| for (int i = 0; i < node.typeParameters.length; i++) { |
| StructuralParameter parameter = node.typeParameters[i]; |
| types.functionTypeParameterIndex[parameter] = offset + i; |
| } |
| |
| _functionsContainingParameters.removeLast(); |
| _functionStack.removeLast(); |
| } |
| |
| @override |
| void visitStructuralParameterType(StructuralParameterType node) { |
| int slot = _functionForParameter[node.parameter]!; |
| for (int inner = slot + 1; inner < _functionStack.length; inner++) { |
| _functionsContainingParameters[slot].add(_functionStack[inner]); |
| } |
| } |
| } |
