mirror of
https://github.com/dart-lang/sdk
synced 2024-11-02 12:24:24 +00:00
[dart2wasm] Add Wasm bottom heap types
- Add getters for the top and bottom types of the WasmGC hierarchy that a type belongs to. - Rename the internal common supertype from `top` to `common` to avoid confusion with the top type of each hierarchy. - Always use a bottom type when emitting a `ref.null` instruction. - Translate the `Null` and `Never` Dart types to WasmGC `nullref`. Change-Id: I43ba5da222a848214647980f7b4876940546242a Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/268463 Reviewed-by: Ömer Ağacan <omersa@google.com> Commit-Queue: Aske Simon Christensen <askesc@google.com>
This commit is contained in:
Aske Simon Christensen
Commit Queue
parent
e0874df618
commit
2846cb8da6
7 changed files with 236 additions and 63 deletions
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@ -547,7 +547,7 @@ class CodeGenerator extends ExpressionVisitor1<w.ValueType, w.ValueType>
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w.ValueType returnType = function.type.outputs[0];
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if (returnType is w.RefType && returnType.nullable) {
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// Dart body may have an implicit return null.
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b.ref_null(returnType.heapType);
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b.ref_null(returnType.heapType.bottomType);
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} else {
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// This point is unreachable, but the Wasm validator still expects the
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// stack to contain a value matching the Wasm function return type.
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@ -95,7 +95,7 @@ class Constants {
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w.Instructions ib = emptyTypeList.initializer;
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ib.i32_const(info.classId);
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ib.i32_const(initialIdentityHash);
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ib.ref_null(typeInfo.struct); // Initialized later
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ib.ref_null(w.HeapType.none); // Initialized later
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ib.i64_const(0);
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ib.array_new_fixed(arrayType, 0);
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ib.struct_new(info.struct);
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@ -282,11 +282,8 @@ class ConstantInstantiator extends ConstantVisitor<w.ValueType> {
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@override
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w.ValueType visitNullConstant(NullConstant node) {
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w.ValueType expectedType = this.expectedType;
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w.HeapType heapType =
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expectedType is w.RefType ? expectedType.heapType : w.HeapType.data;
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b.ref_null(heapType);
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return w.RefType(heapType, nullable: true);
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b.ref_null(w.HeapType.none);
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return const w.RefType.none(nullable: true);
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}
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w.ValueType _maybeBox(w.ValueType wasmType, void Function() pushValue) {
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@ -352,7 +349,7 @@ class ConstantCreator extends ConstantVisitor<ConstantInfo?> {
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// Create uninitialized global and function to initialize it.
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w.DefinedGlobal global =
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m.addGlobal(w.GlobalType(type.withNullability(true)));
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global.initializer.ref_null(type.heapType);
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global.initializer.ref_null(w.HeapType.none);
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global.initializer.end();
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w.FunctionType ftype = m.addFunctionType(const [], [type]);
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w.DefinedFunction function = m.addFunction(ftype, "$constant");
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@ -507,7 +507,7 @@ class DynamicDispatcher {
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// `noSuchMethod` if the supplied number of arguments is less than the
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// number required for any given selector.
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for (int i = positionalArguments.length; i < maxParameterCount; i++) {
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b.ref_null(translator.topInfo.nullableType.heapType);
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b.ref_null(w.HeapType.none);
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}
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b.call(dynamicTrampolines[type]![name]!);
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return translator.topInfo.nullableType;
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@ -112,7 +112,7 @@ class Globals {
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if (type is w.RefType) {
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w.HeapType heapType = type.heapType;
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if (type.nullable) {
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b.ref_null(heapType);
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b.ref_null(heapType.bottomType);
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} else {
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b.global_get(_prepareDummyValue(type)!);
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}
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@ -606,10 +606,8 @@ class Translator {
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if (type is DynamicType || type is VoidType) {
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return topInfo.nullableType;
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}
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// TODO(joshualitt): When we add support to `wasm_builder` for bottom heap
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// types, we should return bottom heap type here.
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if (type is NullType || type is NeverType) {
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return topInfo.nullableType;
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return const w.RefType.none(nullable: true);
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}
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if (type is TypeParameterType) {
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return translateStorageType(type.isPotentiallyNullable
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@ -828,7 +826,7 @@ class Translator {
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// This can happen when a void method has its return type overridden
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// to return a value, in which case the selector signature will have a
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// non-void return type to encompass all possible return values.
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b.ref_null((to as w.RefType).heapType);
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b.ref_null((to as w.RefType).heapType.bottomType);
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return;
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}
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}
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@ -875,8 +873,11 @@ class Translator {
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var heapType = (to as w.RefType).heapType;
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if (heapType is w.FunctionType) {
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b.ref_cast(heapType);
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return;
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}
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} else if (heapType == w.HeapType.none) {
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assert(to.nullable);
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b.drop();
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b.ref_null(w.HeapType.none);
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} else {
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w.Label? nullLabel = null;
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if (!(from as w.RefType).heapType.isSubtypeOf(w.HeapType.data)) {
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if (from.nullable && to.nullable) {
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@ -889,7 +890,7 @@ class Translator {
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b.block(const [], [from.withNullability(false)]);
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b.local_get(temp);
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b.br_on_non_null(nonNullLabel);
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b.ref_null(to.heapType);
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b.ref_null(w.HeapType.none);
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b.br(nullLabel);
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b.end(); // nonNullLabel
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}
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@ -903,6 +904,7 @@ class Translator {
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}
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}
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}
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}
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if (!fromIsExtern && toIsExtern) {
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b.extern_externalize();
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@ -223,7 +223,7 @@ class Instructions with SerializerMixin {
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}
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ValueType get _topOfStack {
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if (!reachable) return RefType.top(nullable: true);
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if (!reachable) return RefType.common(nullable: true);
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if (_stackTypes.isEmpty) _reportError("Stack underflow");
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return _stackTypes.last;
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}
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@ -885,7 +885,7 @@ class Instructions with SerializerMixin {
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/// Emit a `ref.is_null` instruction.
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void ref_is_null() {
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assert(_verifyTypes(
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const [RefType.top(nullable: true)], const [NumType.i32],
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const [RefType.common(nullable: true)], const [NumType.i32],
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trace: const ['ref.is_null']));
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writeByte(0xD1);
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}
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@ -900,7 +900,7 @@ class Instructions with SerializerMixin {
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/// Emit a `ref.as_non_null` instruction.
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void ref_as_non_null() {
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assert(_verifyTypes(const [RefType.top(nullable: true)],
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assert(_verifyTypes(const [RefType.common(nullable: true)],
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[_topOfStack.withNullability(false)],
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trace: const ['ref.as_non_null']));
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writeByte(0xD3);
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@ -908,7 +908,7 @@ class Instructions with SerializerMixin {
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/// Emit a `br_on_null` instruction.
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void br_on_null(Label label) {
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assert(_verifyTypes(const [RefType.top(nullable: true)],
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assert(_verifyTypes(const [RefType.common(nullable: true)],
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[_topOfStack.withNullability(false)],
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trace: ['br_on_null', label]));
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assert(_verifyBranchTypes(label, 1));
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@ -928,7 +928,7 @@ class Instructions with SerializerMixin {
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/// Emit a `br_on_non_null` instruction.
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void br_on_non_null(Label label) {
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assert(_verifyBranchTypes(label, 1, [_topOfStack.withNullability(false)]));
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assert(_verifyTypes(const [RefType.top(nullable: true)], const [],
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assert(_verifyTypes(const [RefType.common(nullable: true)], const [],
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trace: ['br_on_non_null', label]));
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writeByte(0xD6);
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_writeLabel(label);
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@ -143,8 +143,9 @@ class RefType extends ValueType {
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const RefType._(this.heapType, this.nullable);
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/// Internal top type above any, func and extern. Not a real Wasm ref type.
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const RefType.top({required bool nullable}) : this._(HeapType.top, nullable);
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/// Internal supertype above any, func and extern. Not a real Wasm ref type.
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const RefType.common({required bool nullable})
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: this._(HeapType.common, nullable);
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/// A (possibly nullable) reference to the `any` heap type.
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const RefType.extern({required bool nullable})
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@ -167,6 +168,18 @@ class RefType extends ValueType {
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/// A (possibly nullable) reference to the `i31` heap type.
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const RefType.i31({required bool nullable}) : this._(HeapType.i31, nullable);
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/// A (possibly nullable) reference to the `none` heap type.
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const RefType.none({required bool nullable})
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: this._(HeapType.none, nullable);
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/// A (possibly nullable) reference to the `noextern` heap type.
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const RefType.noextern({required bool nullable})
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: this._(HeapType.noextern, nullable);
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/// A (possibly nullable) reference to the `nofunc` heap type.
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const RefType.nofunc({required bool nullable})
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: this._(HeapType.nofunc, nullable);
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/// A (possibly nullable) reference to a custom heap type.
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RefType.def(DefType defType, {required bool nullable})
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: this(defType, nullable: nullable);
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@ -195,7 +208,9 @@ class RefType extends ValueType {
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@override
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String toString() {
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if (nullable == heapType.nullableByDefault) return "${heapType}ref";
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if (nullable == heapType.nullableByDefault) {
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return "${heapType.shorthandName}ref";
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}
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return "ref${nullable ? " null " : " "}$heapType";
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}
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@ -213,8 +228,8 @@ class RefType extends ValueType {
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abstract class HeapType implements Serializable {
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const HeapType();
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/// Internal top type above any, func and extern. Not a real Wasm heap type.
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static const top = TopHeapType._();
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/// Internal supertype above any, func and extern. Not a real Wasm heap type.
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static const common = CommonHeapType._();
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/// The `extern` heap type.
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static const extern = ExternHeapType._();
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@ -234,37 +249,61 @@ abstract class HeapType implements Serializable {
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/// The `i31` heap type.
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static const i31 = I31HeapType._();
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/// The `none` heap type.
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static const none = NoneHeapType._();
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/// The `noextern` heap type.
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static const noextern = NoExternHeapType._();
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/// The `nofunc` heap type.
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static const nofunc = NoFuncHeapType._();
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/// Whether this heap type is nullable by default, i.e. when written with the
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/// -`ref` shorthand. A `null` value here means the heap type has no default
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/// nullability, so the nullability of a reference has to be specified
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/// explicitly.
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bool? get nullableByDefault;
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/// The top type of the hierarchy containing this type.
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HeapType get topType;
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/// The bottom type of the hierarchy containing this type.
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HeapType get bottomType;
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/// Whether this heap type is a declared subtype of the other heap type.
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bool isSubtypeOf(HeapType other);
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/// Whether this heap type is a structural subtype of the other heap type.
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bool isStructuralSubtypeOf(HeapType other) => isSubtypeOf(other);
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String get shorthandName => toString();
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}
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/// Internal top type above any, func and extern. This is only used to specify
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/// Internal supertype above any, func and extern. This is only used to specify
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/// input constraints for instructions that are polymorphic across the three
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/// type hierarchies. It's not a real Wasm heap type.
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class TopHeapType extends HeapType {
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const TopHeapType._();
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class CommonHeapType extends HeapType {
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const CommonHeapType._();
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@override
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bool? get nullableByDefault => null;
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@override
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bool isSubtypeOf(HeapType other) => other == HeapType.top;
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HeapType get topType => throw "No top type of internal common supertype";
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@override
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HeapType get bottomType =>
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throw "No bottom type of internal common supertype";
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@override
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bool isSubtypeOf(HeapType other) => other == HeapType.common;
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@override
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void serialize(Serializer s) =>
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throw "Attempt to serialize internal top type";
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throw "Attempt to serialize internal common supertype";
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@override
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String toString() => "#top";
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String toString() => "#common";
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}
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/// The `extern` heap type.
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@ -276,9 +315,15 @@ class ExternHeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.extern;
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@override
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HeapType get bottomType => HeapType.noextern;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top || other == HeapType.extern;
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other == HeapType.common || other == HeapType.extern;
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@override
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void serialize(Serializer s) => s.writeByte(0x6F);
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@ -296,9 +341,15 @@ class AnyHeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.any;
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@override
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HeapType get bottomType => HeapType.none;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top || other == HeapType.any;
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other == HeapType.common || other == HeapType.any;
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@override
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void serialize(Serializer s) => s.writeByte(0x6E);
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@ -316,9 +367,15 @@ class EqHeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.any;
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@override
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HeapType get bottomType => HeapType.none;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top || other == HeapType.any || other == HeapType.eq;
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other == HeapType.common || other == HeapType.any || other == HeapType.eq;
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@override
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void serialize(Serializer s) => s.writeByte(0x6D);
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@ -336,9 +393,15 @@ class FuncHeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.func;
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@override
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HeapType get bottomType => HeapType.nofunc;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top || other == HeapType.func;
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other == HeapType.common || other == HeapType.func;
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@override
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void serialize(Serializer s) => s.writeByte(0x70);
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@ -356,9 +419,15 @@ class DataHeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.any;
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@override
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HeapType get bottomType => HeapType.none;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top ||
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other == HeapType.common ||
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other == HeapType.any ||
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other == HeapType.eq ||
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other == HeapType.data;
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@ -379,9 +448,15 @@ class I31HeapType extends HeapType {
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.any;
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@override
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HeapType get bottomType => HeapType.none;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.top ||
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other == HeapType.common ||
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other == HeapType.any ||
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other == HeapType.eq ||
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other == HeapType.i31;
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@ -393,6 +468,93 @@ class I31HeapType extends HeapType {
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String toString() => "i31";
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}
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/// The `none` heap type.
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class NoneHeapType extends HeapType {
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const NoneHeapType._();
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static const defaultNullability = true;
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.any;
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@override
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HeapType get bottomType => HeapType.none;
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@override
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bool isSubtypeOf(HeapType other) =>
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other == HeapType.common || other.bottomType == HeapType.none;
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@override
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void serialize(Serializer s) => s.writeByte(0x65);
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@override
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String toString() => "none";
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@override
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String get shorthandName => "null";
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}
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/// The `noextern` heap type.
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class NoExternHeapType extends HeapType {
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const NoExternHeapType._();
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static const defaultNullability = true;
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@override
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bool? get nullableByDefault => defaultNullability;
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@override
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HeapType get topType => HeapType.extern;
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@override
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HeapType get bottomType => HeapType.noextern;
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@override
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bool isSubtypeOf(HeapType other) =>
|
||||
other == HeapType.common || other.bottomType == HeapType.noextern;
|
||||
|
||||
@override
|
||||
void serialize(Serializer s) => s.writeByte(0x69);
|
||||
|
||||
@override
|
||||
String toString() => "extern";
|
||||
|
||||
@override
|
||||
String get shorthandName => "nullextern";
|
||||
}
|
||||
|
||||
/// The `nofunc` heap type.
|
||||
class NoFuncHeapType extends HeapType {
|
||||
const NoFuncHeapType._();
|
||||
|
||||
static const defaultNullability = true;
|
||||
|
||||
@override
|
||||
bool? get nullableByDefault => defaultNullability;
|
||||
|
||||
@override
|
||||
HeapType get topType => HeapType.func;
|
||||
|
||||
@override
|
||||
HeapType get bottomType => HeapType.nofunc;
|
||||
|
||||
@override
|
||||
bool isSubtypeOf(HeapType other) =>
|
||||
other == HeapType.common || other.bottomType == HeapType.nofunc;
|
||||
|
||||
@override
|
||||
void serialize(Serializer s) => s.writeByte(0x68);
|
||||
|
||||
@override
|
||||
String toString() => "nofunc";
|
||||
|
||||
@override
|
||||
String get shorthandName => "nullfunc";
|
||||
}
|
||||
|
||||
/// A custom heap type.
|
||||
abstract class DefType extends HeapType {
|
||||
int? _index;
|
||||
|
|
@ -453,12 +615,18 @@ class FunctionType extends DefType {
|
|||
@override
|
||||
HeapType get abstractSuperType => HeapType.func;
|
||||
|
||||
@override
|
||||
HeapType get topType => HeapType.func;
|
||||
|
||||
@override
|
||||
HeapType get bottomType => HeapType.nofunc;
|
||||
|
||||
@override
|
||||
Iterable<StorageType> get constituentTypes => [...inputs, ...outputs];
|
||||
|
||||
@override
|
||||
bool isStructuralSubtypeOf(HeapType other) {
|
||||
if (other == HeapType.top || other == HeapType.func) return true;
|
||||
if (other == HeapType.common || other == HeapType.func) return true;
|
||||
if (other is! FunctionType) return false;
|
||||
if (inputs.length != other.inputs.length) return false;
|
||||
if (outputs.length != other.outputs.length) return false;
|
||||
|
|
@ -490,6 +658,12 @@ abstract class DataType extends DefType {
|
|||
|
||||
DataType(this.name, {super.superType});
|
||||
|
||||
@override
|
||||
HeapType get topType => HeapType.any;
|
||||
|
||||
@override
|
||||
HeapType get bottomType => HeapType.none;
|
||||
|
||||
@override
|
||||
String toString() => name;
|
||||
}
|
||||
|
|
@ -512,7 +686,7 @@ class StructType extends DataType {
|
|||
|
||||
@override
|
||||
bool isStructuralSubtypeOf(HeapType other) {
|
||||
if (other == HeapType.top ||
|
||||
if (other == HeapType.common ||
|
||||
other == HeapType.any ||
|
||||
other == HeapType.eq ||
|
||||
other == HeapType.data) {
|
||||
|
|
@ -550,7 +724,7 @@ class ArrayType extends DataType {
|
|||
|
||||
@override
|
||||
bool isStructuralSubtypeOf(HeapType other) {
|
||||
if (other == HeapType.top ||
|
||||
if (other == HeapType.common ||
|
||||
other == HeapType.any ||
|
||||
other == HeapType.eq ||
|
||||
other == HeapType.data) {
|
||||
|
|
|
|||
Loading…
Reference in a new issue