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LibJS: Implement Atomics.compareExchange

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Timothy Flynn 2021-07-12 08:59:34 -04:00 • committed by Linus Groh
parent 655ffce64d
commit 33eb830929
4 changed files with 144 additions and 0 deletions
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78
Userland/Libraries/LibJS/Runtime/AtomicsObject.cpp
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@ -6,6 +6,7 @@
#include <AK/Atomic.h>
#include <AK/ByteBuffer.h>
#include <AK/Endian.h>
#include <LibJS/Runtime/AtomicsObject.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/TypedArray.h>
@ -119,6 +120,7 @@ void AtomicsObject::initialize(GlobalObject& global_object)
u8 attr = Attribute::Writable | Attribute::Configurable;
define_native_function(vm.names.add, add, 3, attr);
define_native_function(vm.names.and_, and_, 3, attr);
define_native_function(vm.names.compareExchange, compare_exchange, 4, attr);
define_native_function(vm.names.exchange, exchange, 3, attr);
define_native_function(vm.names.load, load, 2, attr);
define_native_function(vm.names.or_, or_, 3, attr);
@ -166,6 +168,82 @@ JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::and_)
VERIFY_NOT_REACHED();
}
template<typename T>
static Value atomic_compare_exchange_impl(GlobalObject& global_object, TypedArrayBase& typed_array)
{
auto& vm = global_object.vm();
validate_integer_typed_array(global_object, typed_array);
if (vm.exception())
return {};
auto indexed_position = validate_atomic_access(global_object, typed_array, vm.argument(1));
if (!indexed_position.has_value())
return {};
Value expected;
Value replacement;
if (typed_array.content_type() == TypedArrayBase::ContentType::BigInt) {
expected = vm.argument(2).to_bigint(global_object);
if (vm.exception())
return {};
replacement = vm.argument(3).to_bigint(global_object);
if (vm.exception())
return {};
} else {
expected = Value(vm.argument(2).to_integer_or_infinity(global_object));
if (vm.exception())
return {};
replacement = Value(vm.argument(3).to_integer_or_infinity(global_object));
if (vm.exception())
return {};
}
if (typed_array.viewed_array_buffer()->is_detached()) {
vm.throw_exception<TypeError>(global_object, ErrorType::DetachedArrayBuffer);
return {};
}
constexpr bool is_little_endian = __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__;
auto& block = typed_array.viewed_array_buffer()->buffer();
auto expected_bytes = numeric_to_raw_bytes<T>(global_object, expected, is_little_endian);
auto replacement_bytes = numeric_to_raw_bytes<T>(global_object, replacement, is_little_endian);
// FIXME: Implement SharedArrayBuffer case.
auto raw_bytes_read = block.slice(*indexed_position, sizeof(T));
if constexpr (IsFloatingPoint<T>) {
VERIFY_NOT_REACHED();
} else {
using U = Conditional<IsSame<ClampedU8, T>, u8, T>;
auto* v = reinterpret_cast<U*>(block.span().slice(*indexed_position).data());
auto* e = reinterpret_cast<U*>(expected_bytes.data());
auto* r = reinterpret_cast<U*>(replacement_bytes.data());
(void)AK::atomic_compare_exchange_strong(v, *e, *r);
}
return raw_bytes_to_numeric<T>(global_object, raw_bytes_read, is_little_endian);
}
// 25.4.5 Atomics.compareExchange ( typedArray, index, expectedValue, replacementValue ), https://tc39.es/ecma262/#sec-atomics.compareexchange
JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::compare_exchange)
{
auto* typed_array = typed_array_from(global_object, vm.argument(0));
if (!typed_array)
return {};
#define __JS_ENUMERATE(ClassName, snake_name, PrototypeName, ConstructorName, Type) \
if (is<ClassName>(typed_array)) \
return atomic_compare_exchange_impl<Type>(global_object, *typed_array);
JS_ENUMERATE_TYPED_ARRAYS
#undef __JS_ENUMERATE
VERIFY_NOT_REACHED();
}
// 25.4.6 Atomics.exchange ( typedArray, index, value ), https://tc39.es/ecma262/#sec-atomics.exchange
JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::exchange)
{