Simon Binder
7d8cd032dc
This adds the `Memory` class to `dart:_wasm`, allowing Dart code to
load and store numeric types in linear memory.
Since `dart2wasm` doesn't generate a memory instance by default, there
is no singleton instance of `Memory`. Instead, memories are defined as
`external` top-level getters annotated with a pragma like
`@pragma('wasm:memory-tyype', MemoryType(limits: Limits(1, 10)))` to
declare their type.
Interop happens in a static way: Methods on `Memory` cannot be torn-off
and, since the target memory is encoded directly in the store/load
instruction, there's also no polymorphism for memories in Dart.
Attempting to call methods on a memory instance that isn't a direct
reference to its definition is a compile-time error.
Memories can also be imported and exported through the existing
`wasm:import` and `wasm:export` pragmas.
TEST=tests/web/wasm/memory_test.dart
Change-Id: I726f33ac2ec04afab55c5a2b6bc09079d0193e02
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/470020
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
61 lines
1.7 KiB
Dart
61 lines
1.7 KiB
Dart
// Copyright (c) 2026, 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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// dart2wasmOptions=--extra-compiler-option=--enable-experimental-wasm-interop
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import 'dart:_wasm';
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import 'package:expect/expect.dart';
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@pragma('wasm:memory-type', MemoryType(limits: Limits(1, 10)))
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external Memory get _memory;
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void main() {
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_testSizeAndGrow();
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_testFill();
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_testFloat();
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_testInt();
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_testOffset();
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}
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void _testSizeAndGrow() {
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Expect.equals(1, _memory.size);
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Expect.equals(1, _memory.grow(1));
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Expect.equals(2, _memory.size);
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Expect.equals(0, _memory.loadInt32(Memory.pageSize + 1).toIntSigned());
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Expect.equals(-1, _memory.grow(20));
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}
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void _testFill() {
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_memory.fill(WasmI32.fromInt(42), 0, 1024);
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for (var i = 0; i < 1024; i++) {
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Expect.equals(42, _memory.loadUint8(i).toIntSigned());
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}
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}
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void _testFloat() {
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_memory.storeFloat64(0, WasmF64.fromDouble(1.5));
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Expect.equals(1.5, _memory.loadFloat64(0).toDouble());
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_memory.storeFloat32(0, WasmF32.fromDouble(1.5));
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Expect.equals(1.5, _memory.loadFloat32(0).toDouble());
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}
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void _testInt() {
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_memory.storeInt8(0, WasmI32.fromInt(-1));
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Expect.equals(-1, _memory.loadInt8(0).toIntSigned());
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Expect.equals(255, _memory.loadUint8(0).toIntUnsigned());
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}
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void _testOffset() {
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_memory.storeInt32(0, WasmI32.fromInt(0x01020304));
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Expect.equals(0x01, _memory.loadInt8(0, offset: 3).toIntSigned());
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Expect.equals(0x02, _memory.loadInt8(0, offset: 2).toIntSigned());
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Expect.equals(0x03, _memory.loadInt8(0, offset: 1).toIntSigned());
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Expect.equals(0x04, _memory.loadInt8(0, offset: 0).toIntSigned());
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}
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