ladybird/Libraries/LibWeb/WebAssembly/Global.cpp

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/*
* Copyright (c) 2024, Andrew Kaster <andrew@ladybird.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Runtime/Realm.h>
#include <LibJS/Runtime/VM.h>
#include <LibWasm/Types.h>
#include <LibWeb/Bindings/GlobalPrototype.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/WebAssembly/Global.h>
#include <LibWeb/WebAssembly/WebAssembly.h>
namespace Web::WebAssembly {
GC_DEFINE_ALLOCATOR(Global);
// https://webassembly.github.io/spec/js-api/#tovaluetype
static Wasm::ValueType to_value_type(Bindings::ValueType type)
{
switch (type) {
case Bindings::ValueType::I32:
return Wasm::ValueType { Wasm::ValueType::I32 };
case Bindings::ValueType::I64:
return Wasm::ValueType { Wasm::ValueType::I64 };
case Bindings::ValueType::F32:
return Wasm::ValueType { Wasm::ValueType::F32 };
case Bindings::ValueType::F64:
return Wasm::ValueType { Wasm::ValueType::F64 };
case Bindings::ValueType::V128:
return Wasm::ValueType { Wasm::ValueType::V128 };
case Bindings::ValueType::Anyfunc:
return Wasm::ValueType { Wasm::ValueType::FunctionReference };
case Bindings::ValueType::Externref:
return Wasm::ValueType { Wasm::ValueType::ExternReference };
}
VERIFY_NOT_REACHED();
}
// https://webassembly.github.io/spec/js-api/#dom-global-global
WebIDL::ExceptionOr<GC::Ref<Global>> Global::construct_impl(JS::Realm& realm, GlobalDescriptor& descriptor, JS::Value v)
{
auto& vm = realm.vm();
// 1. Let mutable be descriptor["mutable"].
auto mutable_ = descriptor.mutable_;
// 2. Let valuetype be ToValueType(descriptor["value"]).
auto value_type = to_value_type(descriptor.value);
// 3. If valuetype is v128,
// 3.1 Throw a TypeError exception.
if (value_type.kind() == Wasm::ValueType::V128)
return vm.throw_completion<JS::TypeError>("V128 is not supported as a global value type"sv);
// 4. If v is missing,
// 4.1 Let value be DefaultValue(valuetype).
// 5. Otherwise,
// 5.1 Let value be ToWebAssemblyValue(v, valuetype).
// FIXME: https://github.com/WebAssembly/spec/issues/1861
// Is there a difference between *missing* and undefined for optional any values?
auto value = v.is_undefined()
? Detail::default_webassembly_value(vm, value_type)
: TRY(Detail::to_webassembly_value(vm, v, value_type));
// 6. If mutable is true, let globaltype be var valuetype; otherwise, let globaltype be const valuetype.
auto global_type = Wasm::GlobalType { value_type, mutable_ };
// 7. Let store be the current agents associated store.
// 8. Let (store, globaladdr) be global_alloc(store, globaltype, value).
// 9. Set the current agents associated store to store.
// 10. Initialize this from globaladdr.
auto& cache = Detail::get_cache(realm);
auto address = cache.abstract_machine().store().allocate(global_type, value);
if (!address.has_value())
return vm.throw_completion<JS::TypeError>("Wasm Global allocation failed"sv);
return realm.create<Global>(realm, *address);
}
Global::Global(JS::Realm& realm, Wasm::GlobalAddress address)
: Bindings::PlatformObject(realm)
, m_address(address)
{
}
// https://webassembly.github.io/spec/js-api/#initialize-a-global-object
void Global::initialize(JS::Realm& realm)
{
Base::initialize(realm);
WEB_SET_PROTOTYPE_FOR_INTERFACE_WITH_CUSTOM_NAME(Global, WebAssembly.Global);
// 1. Let map be the surrounding agent's associated Global object cache.
// 2. Assert: map[globaladdr] doesnt exist.
auto& cache = Detail::get_cache(realm);
auto exists = cache.global_instances().contains(m_address);
VERIFY(!exists);
// 3. Set global.[[Global]] to globaladdr.
// 4. Set map[globaladdr] to global.
cache.add_global_instance(m_address, *this);
}
// https://webassembly.github.io/spec/js-api/#getglobalvalue
static WebIDL::ExceptionOr<JS::Value> get_global_value(Global const& global)
{
// 1. Let store be the current agents associated store.
// 2. Let globaladdr be global.[[Global]].
// 3. Let globaltype be global_type(store, globaladdr).
// 4. If globaltype is of the form mut v128, throw a TypeError.
auto& cache = Detail::get_cache(global.realm());
auto* global_instance = cache.abstract_machine().store().get(global.address());
if (!global_instance)
return global.vm().throw_completion<JS::RangeError>("Could not find the global instance"sv);
auto value_type = global_instance->type().type();
if (value_type.kind() == Wasm::ValueType::V128)
return global.vm().throw_completion<JS::TypeError>("V128 is not supported as a global value type"sv);
// 5. Let value be global_read(store, globaladdr).
auto value = global_instance->value();
// 6. Return ToJSValue(value).
return Detail::to_js_value(global.vm(), value, value_type);
}
// https://webassembly.github.io/spec/js-api/#dom-global-value
WebIDL::ExceptionOr<JS::Value> Global::value() const
{
return get_global_value(*this);
}
// https://webassembly.github.io/spec/js-api/#dom-global-valueof
WebIDL::ExceptionOr<JS::Value> Global::value_of() const
{
return get_global_value(*this);
}
// https://webassembly.github.io/spec/js-api/#dom-global-value
WebIDL::ExceptionOr<void> Global::set_value(JS::Value the_given_value)
{
auto& realm = this->realm();
auto& vm = this->vm();
// 1. Let store be the current agents associated store.
// 2. Let globaladdr be this.[[Global]].
// 3. Let mut valuetype be global_type(store, globaladdr).
// 4. If valuetype is v128, throw a TypeError.
// 5. If mut is const, throw a TypeError.
auto& cache = Detail::get_cache(realm);
auto* global_instance = cache.abstract_machine().store().get(address());
if (!global_instance)
return vm.throw_completion<JS::RangeError>("Could not find the global instance"sv);
auto mut_value_type = global_instance->type();
if (mut_value_type.type().kind() == Wasm::ValueType::V128)
return vm.throw_completion<JS::TypeError>("Cannot set the value of a V128 global"sv);
if (!mut_value_type.is_mutable())
return vm.throw_completion<JS::TypeError>("Cannot set the value of a const global"sv);
// 6. Let value be ToWebAssemblyValue(the given value, valuetype).
auto value = TRY(Detail::to_webassembly_value(vm, the_given_value, mut_value_type.type()));
// 7. Let store be global_write(store, globaladdr, value).
// 8. If store is error, throw a RangeError exception.
// 9. Set the current agents associated store to store.
// Note: The store cannot fail, because we checked for mut/val above.
global_instance->set_value(value);
return {};
}
}