[dart2wasm] Make use of ImmutableWasmArray in core libraries

This can allow tools such as binaryen or V8 optimize loads from the
arrays better.

We'd also want to make some other uses of wasm arrays immutable (e.g.
`WasmArray<_Type>` used in RTT implementation) but it's currently not
easily possible to create immutable wasm arrays of unknown length from
another mutable array (see [0]).

[0] WebAssembly/gc#570

Change-Id: Ia5270bad238c3dc6ea1086677395091d441d9398
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/392904
Reviewed-by: Ömer Ağacan <[email protected]>
Commit-Queue: Martin Kustermann <[email protected]>

pkg/dart2wasm/lib/constants.dart

@@ -243,7 +243,8 @@ class Constants {
       ...type.named.map((named) => named.type),
     ]);
     final names = makeArrayOf(coreTypes.stringNonNullableRawType,
-        type.named.map((t) => StringConstant(t.name)).toList());
+        type.named.map((t) => StringConstant(t.name)).toList(),
+        mutable: false);
     return _makeTypeConstant(translator.recordTypeClass, type.nullability, {
       translator.recordTypeFieldTypesField.fieldReference: fieldTypes,
       translator.recordTypeNamesField.fieldReference: names,

pkg/dart2wasm/lib/record_class_generator.dart

@@ -30,9 +30,9 @@ import 'records.dart';
 ///   Record_2_a(this.$1, this.$2, this.a);
 ///
 ///   @pragma('wasm:entry-point')
-///   bool _checkRecordType(WasmArray<_Type> types, WasmArray<String> names) {
+///   bool _checkRecordType(WasmArray<_Type> types, ImmutableWasmArray<String> names) {
 ///     if (types.length != 3) return false;
-///     if (!identical(names, const WasmArray(["a"]))) return false;
+///     if (!identical(names, const ImmutableWasmArray(["a"]))) return false;
 ///
 ///     if (!_isSubtype($1, types[0])) return false;
 ///     if (!_isSubtype($2, types[1])) return false;
@@ -44,7 +44,7 @@ import 'records.dart';
 ///   @pragma('wasm:entry-point')
 ///   _Type get _masqueradedRecordRuntimeType =>
 ///     _RecordType(
-///       const WasmArray(["a"]),
+///       const ImmutableWasmArray(["a"]),
 ///       WasmArray.literal([
 ///         _getMasqueradedRuntimeTypeNullable($1),
 ///         _getMasqueradedRuntimeTypeNullable($2),
@@ -54,7 +54,7 @@ import 'records.dart';
 ///   @pragma('wasm:entry-point')
 ///   _Type get _recordRuntimeType =>
 ///     _RecordType(
-///       const WasmArray(["a"]),
+///       const ImmutableWasmArray(["a"]),
 ///       WasmArray.literal([
 ///         _getActualRuntimeTypeNullable($1),
 ///         _getActualRuntimeTypeNullable($2),
@@ -126,6 +126,9 @@ class _RecordClassGenerator {
   late final Class wasmArrayClass =
       coreTypes.index.getClass('dart:_wasm', 'WasmArray');
 
+  late final Class immutableWasmArrayClass =
+      coreTypes.index.getClass('dart:_wasm', 'ImmutableWasmArray');
+
   late final Procedure wasmArrayRefLength =
       coreTypes.index.getProcedure('dart:_wasm', 'WasmArrayRef', 'get:length');
 
@@ -144,11 +147,16 @@ class _RecordClassGenerator {
   late final Field wasmArrayValueField =
       coreTypes.index.getField("dart:_wasm", "WasmArray", "_value");
 
+  late final Field immutableWasmArrayValueField =
+      coreTypes.index.getField("dart:_wasm", "ImmutableWasmArray", "_value");
+
   late final InterfaceType wasmArrayOfType = InterfaceType(
       wasmArrayClass, Nullability.nonNullable, [nonNullableTypeType]);
 
-  late final InterfaceType wasmArrayOfString = InterfaceType(
-      wasmArrayClass, Nullability.nonNullable, [nonNullableStringType]);
+  late final InterfaceType immutableWasmArrayOfString = InterfaceType(
+      immutableWasmArrayClass,
+      Nullability.nonNullable,
+      [nonNullableStringType]);
 
   late final InterfaceType runtimeTypeType =
       InterfaceType(typeRuntimetypeTypeClass, Nullability.nonNullable);
@@ -414,7 +422,7 @@ class _RecordClassGenerator {
   Procedure _generateCheckRecordType(RecordShape shape, List<Field> fields) {
     final typesParameter = VariableDeclaration('types', type: wasmArrayOfType);
     final namesParameter =
-        VariableDeclaration('names', type: wasmArrayOfString);
+        VariableDeclaration('names', type: immutableWasmArrayOfString);
 
     final List<Statement> statements = [];
 
@@ -502,7 +510,7 @@ class _RecordClassGenerator {
       String name, Procedure target, RecordShape shape, List<Field> fields) {
     final List<Statement> statements = [];
 
-    // const WasmArray(["name1", "name2", ...])
+    // const ImmutableWasmArray(["name1", "name2", ...])
     final fieldNamesList = ConstantExpression(_fieldNamesConstant(shape));
 
     Expression fieldRuntimeTypeExpr(Field field) => StaticInvocation(
@@ -548,10 +556,11 @@ class _RecordClassGenerator {
   }
 
   Constant _fieldNamesConstant(RecordShape shape) {
-    return InstanceConstant(wasmArrayClass.reference, [
+    return InstanceConstant(immutableWasmArrayClass.reference, [
       nonNullableStringType
     ], {
-      wasmArrayValueField.fieldReference: ListConstant(nonNullableStringType,
+      immutableWasmArrayValueField.fieldReference: ListConstant(
+          nonNullableStringType,
           shape.names.map((name) => StringConstant(name)).toList())
     });
   }

pkg/dart2wasm/lib/types.dart

@@ -202,7 +202,8 @@ class Types {
 
     final names = translator.constants.makeArrayOf(
         translator.coreTypes.stringNonNullableRawType,
-        type.named.map((t) => StringConstant(t.name)).toList());
+        type.named.map((t) => StringConstant(t.name)).toList(),
+        mutable: false);
 
     translator.constants.instantiateConstant(
         codeGen.b, names, recordTypeNamesFieldExpectedType);

sdk/lib/_internal/wasm/lib/convert_patch.dart

@@ -1067,8 +1067,7 @@ mixin _ChunkedJsonParser<T> on _JsonParserWithListener {
    * }
    * ```
    */
-  static const WasmArray<WasmI8> _characterAttributes =
-      WasmArray<WasmI8>.literal([
+  static const _characterAttributes = ImmutableWasmArray<WasmI8>.literal([
     33, 33, 33, 33, 33, 33, 33, 33, 33, 35, 35, 33, 33, 35, 33, 33, 33, 33, //
     33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 33, 34, 32, 33, 32, //
     32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, //
@@ -1776,7 +1775,7 @@ class _Utf8Decoder {
   // Non-BMP   'R' = 64 + (2 | flagNonLatin1);
   // Illegal   'a' = 64 + (1 | flagIllegal);
   // Illegal   'b' = 64 + (2 | flagIllegal);
-  static const WasmArray<WasmI8> scanTable = WasmArray<WasmI8>.literal([
+  static const scanTable = ImmutableWasmArray<WasmI8>.literal([
     // 00-1F
     65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65,
     65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65, 65,

sdk/lib/_internal/wasm/lib/int_patch.dart

@@ -210,7 +210,7 @@ class int {
   }
 
   // For each radix, 2-36, how many digits are guaranteed to fit in an `int`.
-  static const _PARSE_LIMITS = const WasmArray<WasmI64>.literal([
+  static const _PARSE_LIMITS = const ImmutableWasmArray<WasmI64>.literal([
     0, // unused
     0, // unused
     63, // radix: 2

sdk/lib/_internal/wasm/lib/record_patch.dart

@@ -12,7 +12,8 @@ abstract class Record {
   _RecordType get _masqueradedRecordRuntimeType;
   _RecordType get _recordRuntimeType;
 
-  bool _checkRecordType(WasmArray<_Type> types, WasmArray<String> names);
+  bool _checkRecordType(
+      WasmArray<_Type> types, ImmutableWasmArray<String> names);
 
   @pragma("wasm:prefer-inline")
   static _RecordType _getRecordRuntimeType(Record record) =>

sdk/lib/_internal/wasm/lib/string.dart

@@ -1452,7 +1452,7 @@ final class OneByteString extends StringBase {
   // Lower-case conversion table for Latin-1 as string.
   // Upper-case ranges: 0x41-0x5a ('A' - 'Z'), 0xc0-0xd6, 0xd8-0xde.
   // Conversion to lower case performed by adding 0x20.
-  static const WasmArray<WasmI8> _LC_TABLE = WasmArray<WasmI8>.literal([
+  static const _LC_TABLE = ImmutableWasmArray<WasmI8>.literal([
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, //
     0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, //
     0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, //
@@ -1484,7 +1484,7 @@ final class OneByteString extends StringBase {
   // The German "sharp s" \xdf (ß) should be converted into two characters (SS),
   // and is also marked with 0x00.
   // Conversion to lower case performed by subtracting 0x20.
-  static const WasmArray<WasmI8> _UC_TABLE = WasmArray<WasmI8>.literal([
+  static const _UC_TABLE = ImmutableWasmArray<WasmI8>.literal([
     0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, //
     0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, //
     0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23, //

sdk/lib/_internal/wasm/lib/type.dart

@@ -57,7 +57,7 @@ extension on WasmArray<_NamedParameter> {
   }
 }
 
-extension on WasmArray<String> {
+extension on ImmutableWasmArray<String> {
   @pragma("wasm:prefer-inline")
   bool get isNotEmpty => length != 0;
 }
@@ -544,7 +544,7 @@ class _AbstractRecordType extends _Type {
 
 @pragma("wasm:entry-point")
 class _RecordType extends _Type {
-  final WasmArray<String> names;
+  final ImmutableWasmArray<String> names;
   final WasmArray<_Type> fieldTypes;
 
   @pragma("wasm:entry-point")