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>
46 lines
1.5 KiB
Dart
46 lines
1.5 KiB
Dart
// Copyright (c) 2026, 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.
|
|
|
|
// dart2wasmOptions=--extra-compiler-option=--enable-experimental-wasm-interop
|
|
|
|
import 'dart:_wasm';
|
|
|
|
external Memory get missingAnnotation;
|
|
// ^
|
|
// [web] This external getter returns a memory instance, but no annotation describing it was found
|
|
|
|
@pragma('wasm:memory-type', MemoryType(limits: Limits(1, 10)))
|
|
external Memory get validDefinition;
|
|
|
|
void main() {
|
|
validDefinition.loadUint8(10);
|
|
validDefinition.size;
|
|
|
|
print(validDefinition);
|
|
// ^
|
|
// [web] WebAssembly elements may only be referenced to directly call a method on them.
|
|
|
|
print(validDefinition.fill);
|
|
// ^
|
|
// [web] This intrinsic extension member may not be torn off.
|
|
}
|
|
|
|
void invalidDynamicMemory(Memory memory) {
|
|
memory.loadUint8(10);
|
|
// ^
|
|
// [web] The receiver of this call must be a top-level variable describing the WebAssembly element.
|
|
}
|
|
|
|
int get notAConstant => 3;
|
|
|
|
void invalidNonConstantArguments() {
|
|
validDefinition.loadUint8(0, offset: 12, align: 1);
|
|
validDefinition.loadUint8(0, offset: notAConstant);
|
|
// ^
|
|
// [web] The variable 'offset' is not a constant, only constant expressions are allowed.
|
|
validDefinition.loadUint8(0, align: notAConstant);
|
|
// ^
|
|
// [web] The variable 'align' is not a constant, only constant expressions are allowed.
|
|
}
|