pkg/dart2wasm/lib/kernel_nodes.dart

// 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 'package:kernel/ast.dart';
import 'package:kernel/core_types.dart';
import 'package:kernel/library_index.dart';

/// Kernel nodes for classes and members referenced specifically by the
/// compiler.
mixin KernelNodes {
  LibraryIndex get index;
  bool get isStandalone;

  CoreTypes get coreTypes;

  // dart:_internal classes
  late final Class symbolClass = index.getClass("dart:_internal", "Symbol");

  String get _stringImplClassName =>
      isStandalone ? "EmbedderStringImpl" : "JSStringImpl";

  // dart:_js_types classes
  late final Class stringImplClass = index.getClass(
    "dart:_string",
    _stringImplClassName,
  );

  // dart:collection classes
  late final Class hashFieldBaseClass = index.getClass(
    "dart:_compact_hash",
    "_HashFieldBase",
  );
  late final Class immutableMapClass = index.getClass(
    "dart:_compact_hash",
    "_ConstMap",
  );
  late final Class immutableSetClass = index.getClass(
    "dart:_compact_hash",
    "_ConstSet",
  );

  // dart:core various classes
  late final Class boxedBoolClass = index.getClass(
    "dart:_boxed_bool",
    "BoxedBool",
  );
  late final Class boxedDoubleClass = index.getClass(
    "dart:_boxed_double",
    "BoxedDouble",
  );
  late final Class boxedIntClass = index.getClass(
    "dart:_boxed_int",
    "BoxedInt",
  );
  late final Class closureClass = index.getClass("dart:core", "_Closure");
  late final Class listBaseClass = index.getClass("dart:_list", "WasmListBase");
  late final Field listBaseLengthField = index.getField(
    "dart:_list",
    "WasmListBase",
    "_length",
  );
  late final Field listBaseDataField = index.getField(
    "dart:_list",
    "WasmListBase",
    "_data",
  );
  late final Procedure listBaseIndexOperator = index.getProcedure(
    "dart:_list",
    "WasmListBase",
    "[]",
  );
  late final Class immutableListClass = index.getClass(
    "dart:_list",
    "ImmutableList",
  );
  late final Class invocationClass = index.getClass("dart:core", 'Invocation');
  late final Class noSuchMethodErrorClass = index.getClass(
    "dart:core",
    "NoSuchMethodError",
  );
  late final Class typeErrorClass = index.getClass("dart:core", "_TypeError");
  late final Field enumIndexField = index.getField(
    'dart:core',
    '_Enum',
    'index',
  );

  // dart:core runtime type classes
  late final Class typeClass = index.getClass("dart:core", "_Type");
  late final Field typeIsDeclaredNullableField = index.getField(
    "dart:core",
    "_Type",
    "isDeclaredNullable",
  );
  late final InterfaceType typeType = InterfaceType(
    typeClass,
    Nullability.nonNullable,
  );
  late final Class abstractFunctionTypeClass = index.getClass(
    "dart:core",
    "_AbstractFunctionType",
  );
  late final Class functionTypeClass = index.getClass(
    "dart:core",
    "_FunctionType",
  );
  late final Field functionTypeTypeParameterOffsetField = index.getField(
    "dart:core",
    "_FunctionType",
    "typeParameterOffset",
  );
  late final Field functionTypeTypeParameterBoundsField = index.getField(
    "dart:core",
    "_FunctionType",
    "typeParameterBounds",
  );
  late final Field functionTypeTypeParameterDefaultsField = index.getField(
    "dart:core",
    "_FunctionType",
    "typeParameterDefaults",
  );
  late final Field functionTypeReturnTypeField = index.getField(
    "dart:core",
    "_FunctionType",
    "returnType",
  );
  late final Field functionTypePositionalParametersField = index.getField(
    "dart:core",
    "_FunctionType",
    "positionalParameters",
  );
  late final Field functionTypeRequiredParameterCountField = index.getField(
    "dart:core",
    "_FunctionType",
    "requiredParameterCount",
  );
  late final Field functionTypeTypeParameterNamedParamsField = index.getField(
    "dart:core",
    "_FunctionType",
    "namedParameters",
  );
  late final Class functionTypeParameterTypeClass = index.getClass(
    "dart:core",
    "_FunctionTypeParameterType",
  );
  late final Field functionTypeParameterTypeIndexField = index.getField(
    "dart:core",
    "_FunctionTypeParameterType",
    "index",
  );
  late final Class futureOrTypeClass = index.getClass(
    "dart:core",
    "_FutureOrType",
  );
  late final Field futureOrTypeTypeArgumentField = index.getField(
    "dart:core",
    "_FutureOrType",
    "typeArgument",
  );
  late final Class interfaceTypeClass = index.getClass(
    "dart:core",
    "_InterfaceType",
  );
  late final Field interfaceTypeClassIdField = index.getField(
    "dart:core",
    "_InterfaceType",
    "classId",
  );
  late final Field interfaceTypeTypeArguments = index.getField(
    "dart:core",
    "_InterfaceType",
    "typeArguments",
  );
  late final Class interfaceTypeParameterTypeClass = index.getClass(
    "dart:core",
    "_InterfaceTypeParameterType",
  );
  late final Field interfaceTypeParameterTypeEnvironmentIndexField = index
      .getField("dart:core", "_InterfaceTypeParameterType", "environmentIndex");
  late final Class namedParameterClass = index.getClass(
    "dart:core",
    "_NamedParameter",
  );
  late final Field namedParameterNameField = index.getField(
    "dart:core",
    "_NamedParameter",
    "name",
  );
  late final Field namedParameterTypeField = index.getField(
    "dart:core",
    "_NamedParameter",
    "type",
  );
  late final Field namedParameterIsRequiredField = index.getField(
    "dart:core",
    "_NamedParameter",
    "isRequired",
  );
  late final InterfaceType namedParameterType = InterfaceType(
    namedParameterClass,
    Nullability.nonNullable,
  );
  late final Class bottomTypeClass = index.getClass("dart:core", "_BottomType");
  late final Class topTypeClass = index.getClass("dart:core", "_TopType");
  late final Field topTypeKindField = index.getField(
    "dart:core",
    "_TopType",
    "_kind",
  );
  late final Class stackTraceClass = index.getClass("dart:core", "StackTrace");
  late final Class abstractRecordTypeClass = index.getClass(
    "dart:core",
    "_AbstractRecordType",
  );
  late final Class recordTypeClass = index.getClass("dart:core", "_RecordType");
  late final Field recordTypeFieldTypesField = index.getField(
    "dart:core",
    "_RecordType",
    "fieldTypes",
  );
  late final Field recordTypeNamesField = index.getField(
    "dart:core",
    "_RecordType",
    "names",
  );
  // dart:core sync* support classes
  late final Class suspendStateClass = index.getClass(
    "dart:core",
    "_SuspendState",
  );
  late final Class syncStarIterableClass = index.getClass(
    "dart:core",
    "_SyncStarIterable",
  );
  late final Class syncStarIteratorClass = index.getClass(
    "dart:core",
    "_SyncStarIterator",
  );

  // async support classes
  late final Class asyncSuspendStateClass = index.getClass(
    "dart:async",
    "_AsyncSuspendState",
  );
  late final Procedure awaitHelper = index.getTopLevelProcedure(
    "dart:async",
    "_awaitHelper",
  );
  late final Procedure awaitHelperWithTypeCheck = index.getTopLevelProcedure(
    "dart:async",
    "_awaitHelperWithTypeCheck",
  );
  late final Procedure newAsyncSuspendState = index.getTopLevelProcedure(
    "dart:async",
    "_newAsyncSuspendState",
  );

  late final Procedure asyncSuspendStateComplete = index.getProcedure(
    "dart:async",
    "_AsyncSuspendState",
    "_complete",
  );
  late final Procedure asyncSuspendStateCompleteError = index.getProcedure(
    "dart:async",
    "_AsyncSuspendState",
    "_completeError",
  );
  late final Procedure makeFuture = index.getTopLevelProcedure(
    "dart:async",
    "_makeFuture",
  );

  // dart:ffi classes
  late final Class ffiPointerClass = index.getClass("dart:ffi", "Pointer");

  // dart:_wasm classes
  late final Library wasmLibrary = index.getLibrary("dart:_wasm");
  late final Class wasmTypesBaseClass = index.getClass(
    "dart:_wasm",
    "_WasmBase",
  );
  late final wasmI8Class = index.getClass("dart:_wasm", "WasmI8");
  late final wasmI16Class = index.getClass("dart:_wasm", "WasmI16");
  late final wasmI32Class = index.getClass("dart:_wasm", "WasmI32");
  late final wasmI32Value = index.getField("dart:_wasm", "WasmI32", "_value");
  late final wasmI64Class = index.getClass("dart:_wasm", "WasmI64");
  late final wasmF32Class = index.getClass("dart:_wasm", "WasmF32");
  late final wasmF64Class = index.getClass("dart:_wasm", "WasmF64");
  late final wasmV128Class = index.getClass("dart:_wasm", "WasmV128");
  late final Class wasmAnyRefClass = index.getClass("dart:_wasm", "WasmAnyRef");
  late final Class wasmExternRefClass = index.getClass(
    "dart:_wasm",
    "WasmExternRef",
  );
  late final Class wasmFuncRefClass = index.getClass(
    "dart:_wasm",
    "WasmFuncRef",
  );
  late final Class wasmEqRefClass = index.getClass("dart:_wasm", "WasmEqRef");
  late final Class wasmStructRefClass = index.getClass(
    "dart:_wasm",
    "WasmStructRef",
  );
  late final Class wasmArrayRefClass = index.getClass(
    "dart:_wasm",
    "WasmArrayRef",
  );
  late final Class wasmFunctionClass = index.getClass(
    "dart:_wasm",
    "WasmFunction",
  );
  late final Class wasmVoidClass = index.getClass("dart:_wasm", "WasmVoid");
  late final Class wasmTableClass = index.getClass("dart:_wasm", "WasmTable");
  late final Class wasmI31RefClass = index.getClass("dart:_wasm", "WasmI31Ref");
  late final Class wasmArrayClass = index.getClass("dart:_wasm", "WasmArray");
  late final Class immutableWasmArrayClass = index.getClass(
    "dart:_wasm",
    "ImmutableWasmArray",
  );
  late final Field wasmArrayValueField = index.getField(
    "dart:_wasm",
    "WasmArray",
    "_value",
  );
  late final Field immutableWasmArrayValueField = index.getField(
    "dart:_wasm",
    "ImmutableWasmArray",
    "_value",
  );
  late final Field uninitializedHashBaseIndex = index.getTopLevelField(
    "dart:_compact_hash",
    "_uninitializedHashBaseIndex",
  );
  late final Field wasmI64ValueField = index.getField(
    "dart:_wasm",
    "WasmI64",
    "_value",
  );

  late final Class wasmMemoryClass = index.getClass('dart:_wasm', 'Memory');
  late final Class wasmMemoryTypeClass = index.getClass(
    'dart:_wasm',
    'MemoryType',
  );
  late final Field wasmLimitsMinimum = index.getField(
    'dart:_wasm',
    'Limits',
    'minimum',
  );
  late final Field wasmLimitsMaximum = index.getField(
    'dart:_wasm',
    'Limits',
    'maximum',
  );

  // dart:_js_helper classes and procedures
  late final Class jsValueClass = index.getClass("dart:_js_helper", "JSValue");
  late final Procedure getInternalizedString = index.getTopLevelProcedure(
    "dart:_js_helper",
    "getInternalizedString",
  );
  late final Procedure areEqualInJS = index.getTopLevelProcedure(
    "dart:_js_helper",
    "areEqualInJS",
  );
  late final Procedure toJSNumber = index.getTopLevelProcedure(
    "dart:_js_helper",
    "toJSNumber",
  );
  late final Procedure boxJsException = index.getTopLevelProcedure(
    "dart:_js_helper",
    "boxJsException",
  );
  late final Procedure jsExceptionStackTrace = index.getTopLevelProcedure(
    "dart:_js_helper",
    "jsExceptionStackTrace",
  );

  // dart:_js_types procedures
  late final Procedure stringImplEquals = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "==",
  );
  late final Procedure stringImplInterpolate = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "_interpolate",
  );
  late final Procedure stringImplInterpolate1 = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "_interpolate1",
  );
  late final Procedure stringImplInterpolate2 = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "_interpolate2",
  );
  late final Procedure stringImplInterpolate3 = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "_interpolate3",
  );
  late final Procedure stringImplInterpolate4 = index.getProcedure(
    "dart:_string",
    _stringImplClassName,
    "_interpolate4",
  );

  // dart:collection procedures and fields
  late final Procedure mapFactory = index.getProcedure(
    "dart:collection",
    "LinkedHashMap",
    "_default",
  );
  late final Procedure mapFromWasmArray = index.getProcedure(
    "dart:_compact_hash",
    "DefaultMap",
    "fromWasmArray",
  );
  late final Procedure setFactory = index.getProcedure(
    "dart:collection",
    "LinkedHashSet",
    "_default",
  );
  late final Procedure setFromWasmArray = index.getProcedure(
    "dart:_compact_hash",
    "DefaultSet",
    "fromWasmArray",
  );
  late final Procedure growableListEmpty = index.getProcedure(
    "dart:_list",
    "GrowableList",
    "empty",
  );
  late final Constructor growableListFromWasmArray = index.getConstructor(
    "dart:_list",
    "GrowableList",
    "_withData",
  );
  late final Procedure hashImmutableIndexNullable = index.getProcedure(
    "dart:collection",
    "_HashAbstractImmutableBase",
    "get:_indexNullable",
  );
  late final Field hashFieldBaseIndexField = index.getField(
    "dart:_compact_hash",
    "_HashFieldBase",
    "_index",
  );
  late final Field hashFieldBaseHashMaskField = index.getField(
    "dart:_compact_hash",
    "_HashFieldBase",
    "_hashMask",
  );
  late final Field hashFieldBaseDataField = index.getField(
    "dart:_compact_hash",
    "_HashFieldBase",
    "_data",
  );
  late final Field hashFieldBaseUsedDataField = index.getField(
    "dart:_compact_hash",
    "_HashFieldBase",
    "_usedData",
  );
  late final Field hashFieldBaseDeletedKeysField = index.getField(
    "dart:_compact_hash",
    "_HashFieldBase",
    "_deletedKeys",
  );

  // dart:core various procedures
  late final Procedure boxedBoolEquals = index.getProcedure(
    "dart:_boxed_bool",
    "BoxedBool",
    "==",
  );
  late final Procedure boxedIntEquals = index.getProcedure(
    "dart:_boxed_int",
    "BoxedInt",
    "==",
  );
  late final Procedure objectHashCode = index.getProcedure(
    "dart:core",
    "Object",
    "get:hashCode",
  );
  late final Procedure objectNoSuchMethod = index.getProcedure(
    "dart:core",
    "Object",
    "noSuchMethod",
  );
  late final Procedure objectGetTypeArguments = index.getProcedure(
    "dart:core",
    "Object",
    "_getTypeArguments",
  );
  late final Procedure objectTypeArguments = index.getProcedure(
    "dart:core",
    "Object",
    "get:_typeArguments",
  );
  late final Procedure nullToString = index.getProcedure(
    "dart:core",
    "Object",
    "_nullToString",
  );
  late final Procedure invokeNoSuchMethod = index.getProcedure(
    "dart:core",
    "Object",
    "_invokeNoSuchMethod",
  );
  late final Procedure invokeNullNoSuchMethod = index.getProcedure(
    "dart:core",
    "Object",
    "_invokeNullNoSuchMethod",
  );
  late final Procedure truncDiv = index.getProcedure(
    "dart:_boxed_int",
    "BoxedInt",
    "_truncDiv",
  );
  late final Procedure runtimeTypeEquals = index.getTopLevelProcedure(
    "dart:core",
    "_runtimeTypeEquals",
  );
  late final Procedure runtimeTypeHashCode = index.getTopLevelProcedure(
    "dart:core",
    "_runtimeTypeHashCode",
  );
  late final Procedure? functionApply = index.tryGetProcedure(
    'dart:core',
    'Function',
    'apply',
  );

  // dart:core invocation/exception procedures
  late final Procedure invocationGetterFactory = index.getProcedure(
    "dart:core",
    "Invocation",
    "getter",
  );
  late final Procedure invocationSetterFactory = index.getProcedure(
    "dart:core",
    "Invocation",
    "setter",
  );
  late final Procedure invocationMethodFactory = index.getProcedure(
    "dart:core",
    "Invocation",
    "method",
  );
  late final Procedure invocationGenericMethodFactory = index.getProcedure(
    "dart:core",
    "Invocation",
    "genericMethod",
  );
  late final Procedure noSuchMethodErrorThrowUnimplementedExternalMemberError =
      index.getProcedure(
        "dart:core",
        "NoSuchMethodError",
        "_throwUnimplementedExternalMemberError",
      );
  late final Procedure stackTraceCurrent = index.getProcedure(
    "dart:core",
    "StackTrace",
    "get:current",
  );
  late final Procedure throwNullCheckErrorWithCurrentStack = index.getProcedure(
    "dart:core",
    "_TypeError",
    "_throwNullCheckErrorWithCurrentStack",
  );
  late final Procedure throwAsCheckError = index.getProcedure(
    "dart:core",
    "_TypeError",
    "_throwAsCheckError",
  );
  late final Procedure throwErrorWithoutDetails = index.getTopLevelProcedure(
    "dart:core",
    "_throwErrorWithoutDetails",
  );
  late final Procedure throwInterfaceTypeAsCheckError1 = index
      .getTopLevelProcedure("dart:core", "_throwInterfaceTypeAsCheckError1");
  late final Procedure throwInterfaceTypeAsCheckError2 = index
      .getTopLevelProcedure("dart:core", "_throwInterfaceTypeAsCheckError2");
  late final Procedure throwInterfaceTypeAsCheckError = index
      .getTopLevelProcedure("dart:core", "_throwInterfaceTypeAsCheckError");
  late final Procedure throwWasmRefError = index.getProcedure(
    "dart:core",
    "_TypeError",
    "_throwWasmRefError",
  );
  late final Procedure throwArgumentTypeCheckError = index.getProcedure(
    "dart:core",
    "_TypeError",
    "_throwArgumentTypeCheckError",
  );
  late final Procedure throwTypeArgumentBoundCheckError = index.getProcedure(
    "dart:core",
    "_TypeError",
    "_throwTypeArgumentBoundCheckError",
  );
  late final Procedure throwAssertionError = index.getProcedure(
    "dart:core",
    "AssertionError",
    "_throwWithMessage",
  );
  late final Procedure rangeErrorCheckValueInInterval = index.getProcedure(
    "dart:core",
    "RangeError",
    "checkValueInInterval",
  );
  late final Class errorClass = index.getClass("dart:core", "Error");
  late final Field errorClassStackTraceField = index.getField(
    "dart:core",
    "Error",
    "_stackTrace",
  );
  late final Procedure errorThrow = index.getProcedure(
    "dart:core",
    "Error",
    "_throw",
  );
  late final Procedure errorThrowWithCurrentStackTrace = index.getProcedure(
    "dart:core",
    "Error",
    "_throwWithCurrentStackTrace",
  );

  // dart:core type procedures
  late final Procedure getClosureRuntimeType = index.getProcedure(
    "dart:core",
    '_Closure',
    "_getClosureRuntimeType",
  );
  late final Procedure getMasqueradedRuntimeType = index.getTopLevelProcedure(
    "dart:core",
    "_getMasqueradedRuntimeType",
  );
  late final Procedure isNullabilityCheck = index.getTopLevelProcedure(
    "dart:core",
    "_isNullabilityCheck",
  );
  late final Procedure isSubtype = index.getTopLevelProcedure(
    "dart:core",
    "_isSubtype",
  );
  late final Procedure isInterfaceSubtype = index.getTopLevelProcedure(
    "dart:core",
    "_isInterfaceSubtype",
  );
  late final Procedure isInterfaceSubtype0 = index.getTopLevelProcedure(
    "dart:core",
    "_isInterfaceSubtype0",
  );
  late final Procedure isInterfaceSubtype1 = index.getTopLevelProcedure(
    "dart:core",
    "_isInterfaceSubtype1",
  );
  late final Procedure isInterfaceSubtype2 = index.getTopLevelProcedure(
    "dart:core",
    "_isInterfaceSubtype2",
  );
  late final Procedure asSubtype = index.getTopLevelProcedure(
    "dart:core",
    "_asSubtype",
  );
  late final Procedure asInterfaceSubtype = index.getTopLevelProcedure(
    "dart:core",
    "_asInterfaceSubtype",
  );
  late final Procedure asInterfaceSubtype0 = index.getTopLevelProcedure(
    "dart:core",
    "_asInterfaceSubtype0",
  );
  late final Procedure asInterfaceSubtype1 = index.getTopLevelProcedure(
    "dart:core",
    "_asInterfaceSubtype1",
  );
  late final Procedure asInterfaceSubtype2 = index.getTopLevelProcedure(
    "dart:core",
    "_asInterfaceSubtype2",
  );
  late final Procedure isTypeSubtype = index.getTopLevelProcedure(
    "dart:core",
    "_isTypeSubtype",
  );
  late final Procedure verifyOptimizedTypeCheck = index.getTopLevelProcedure(
    "dart:core",
    "_verifyOptimizedTypeCheck",
  );
  late final Procedure checkClosureShape = index.getTopLevelProcedure(
    "dart:core",
    "_checkClosureShape",
  );
  late final Procedure checkClosureType = index.getTopLevelProcedure(
    "dart:core",
    "_checkClosureType",
  );
  late final Procedure typeAsNullable = index.getProcedure(
    "dart:core",
    "_Type",
    "get:asNullable",
  );
  late final Procedure createNormalizedFutureOrType = index.getProcedure(
    "dart:core",
    "_TypeUniverse",
    "createNormalizedFutureOrType",
  );
  late final Procedure substituteFunctionTypeArgument = index.getProcedure(
    "dart:core",
    "_TypeUniverse",
    "substituteFunctionTypeArgument",
  );

  // dart:core dynamic invocation helper procedures
  late final Procedure getNamedParameterIndex = index.getTopLevelProcedure(
    "dart:core",
    "_getNamedParameterIndex",
  );
  late final Procedure typeArgumentsToList = index.getTopLevelProcedure(
    "dart:core",
    "_typeArgumentsToList",
  );
  late final Procedure positionalParametersToList = index.getTopLevelProcedure(
    "dart:core",
    "_positionalParametersToList",
  );
  late final Procedure namedParametersToMap = index.getTopLevelProcedure(
    "dart:core",
    "_namedParametersToMap",
  );
  late final Procedure namedParameterMapToArray = index.getTopLevelProcedure(
    "dart:core",
    "_namedParameterMapToArray",
  );
  late final Procedure listOf = index.getProcedure(
    "dart:_list",
    "ModifiableFixedLengthList",
    "of",
  );

  // dart:_wasm procedures
  late final Procedure wasmFunctionCall = index.getProcedure(
    "dart:_wasm",
    "WasmFunction",
    "get:call",
  );
  late final Procedure wasmTableCallIndirect = index.getProcedure(
    "dart:_wasm",
    "WasmTable",
    "callIndirect",
  );

  // Hash utils
  late final Field hashSeed = index.getTopLevelField('dart:core', '_hashSeed');
  late final Procedure systemHashCombine = index.getProcedure(
    "dart:_internal",
    "SystemHash",
    "combine",
  );

  // Deferred loading.
  late final Procedure? checkLibraryIsLoadedFromLoadId = index.tryGetProcedure(
    'dart:_internal',
    LibraryIndex.topLevel,
    'checkLibraryIsLoadedFromLoadId',
  );
  late final Procedure? dartInternalLoadingMapGetter = index.tryGetProcedure(
    'dart:_internal',
    LibraryIndex.topLevel,
    'get:_loadingMap',
  );
  late final Procedure? dartInternalLoadingMapNamesGetter = index
      .tryGetProcedure(
        'dart:_internal',
        LibraryIndex.topLevel,
        'get:_loadingMapNames',
      );

  // Debugging
  late final Procedure printToConsole = index.getTopLevelProcedure(
    "dart:_internal",
    "printToConsole",
  );

  // Standalone embedder imports
  late final Procedure embedderStringFromCharCodeArray = index
      .getTopLevelProcedure('dart:_embedder', 'stringFromCharCodeArray');
  late final Procedure embedderStringFromAsciiBytes = index
      .getTopLevelProcedure('dart:_embedder', 'stringFromAsciiBytes');

  late final Map<Member, (Extension, ExtensionMemberDescriptor)>
  _extensionCache = {};

  (Extension, ExtensionMemberDescriptor) extensionOfMember(Member member) {
    return _extensionCache.putIfAbsent(member, () {
      assert(member.isExtensionMember);

      final memberRef = member.reference;
      for (final ext in member.enclosingLibrary.extensions) {
        for (final descriptor in ext.memberDescriptors) {
          if (memberRef == descriptor.memberReference) {
            return (ext, descriptor);
          }
        }
      }
      throw 'Did not find extension for $member';
    });
  }
}