Aske Simon Christensen
c10ee9971f
Reland of https://dart-review.googlesource.com/c/sdk/+/96081 Change-Id: Ie9e6a0d26703469396fa6ea4803f49ce387f495b Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/97224 Reviewed-by: Kevin Millikin <kmillikin@google.com>
52 lines
1.9 KiB
Dart
52 lines
1.9 KiB
Dart
// Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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library vm.constants_native_effects;
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import '../ast.dart';
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import '../target/targets.dart';
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import '../core_types.dart';
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class VmConstantsBackend extends ConstantsBackend {
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final Class immutableMapClass;
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VmConstantsBackend._(this.immutableMapClass);
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/// If [defines] is not `null` it will be used for handling
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/// `const {bool,...}.fromEnvironment()` otherwise the current VM's values
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/// will be used.
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factory VmConstantsBackend(CoreTypes coreTypes) {
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final Library coreLibrary = coreTypes.coreLibrary;
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final Class immutableMapClass = coreLibrary.classes
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.firstWhere((Class klass) => klass.name == '_ImmutableMap');
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assert(immutableMapClass != null);
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return new VmConstantsBackend._(immutableMapClass);
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}
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@override
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Constant lowerMapConstant(MapConstant constant) {
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// The _ImmutableMap class is implemented via one field pointing to a list
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// of key/value pairs -- see runtime/lib/immutable_map.dart!
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final List<Constant> kvListPairs =
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new List<Constant>(2 * constant.entries.length);
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for (int i = 0; i < constant.entries.length; i++) {
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final ConstantMapEntry entry = constant.entries[i];
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kvListPairs[2 * i] = entry.key;
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kvListPairs[2 * i + 1] = entry.value;
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}
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// This is a bit fishy, since we merge the key and the value type by
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// putting both into the same list.
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final kvListConstant = new ListConstant(const DynamicType(), kvListPairs);
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assert(immutableMapClass.fields.length == 1);
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final Field kvPairListField = immutableMapClass.fields[0];
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return new InstanceConstant(immutableMapClass.reference, <DartType>[
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constant.keyType,
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constant.valueType,
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], <Reference, Constant>{
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kvPairListField.reference: kvListConstant,
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});
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}
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}
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