LibJS: Implement Atomics.store

Author: https://github.com/trflynn89
Commit: https://github.com/SerenityOS/serenity/commit/6211eb0f9a7
Pull-request: https://github.com/SerenityOS/serenity/pull/8656
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/Runtime/AtomicsObject.cpp

@@ -121,6 +121,7 @@ void AtomicsObject::initialize(GlobalObject& global_object)
     define_native_function(vm.names.and_, and_, 3, attr);
     define_native_function(vm.names.load, load, 2, attr);
     define_native_function(vm.names.or_, or_, 3, attr);
+    define_native_function(vm.names.store, store, 3, attr);
     define_native_function(vm.names.sub, sub, 3, attr);
     define_native_function(vm.names.xor_, xor_, 3, attr);
 
@@ -205,6 +206,42 @@ JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::or_)
     VERIFY_NOT_REACHED();
 }
 
+// 25.4.10 Atomics.store ( typedArray, index, value ), https://tc39.es/ecma262/#sec-atomics.store
+JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::store)
+{
+    auto* typed_array = typed_array_from(global_object, vm.argument(0));
+    if (!typed_array)
+        return {};
+
+    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 {};
+
+    auto value = vm.argument(2);
+    Value value_to_set;
+    if (typed_array->content_type() == TypedArrayBase::ContentType::BigInt) {
+        value_to_set = value.to_bigint(global_object);
+        if (vm.exception())
+            return {};
+    } else {
+        value_to_set = Value(value.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 {};
+    }
+
+    typed_array->set_value_in_buffer(*indexed_position, value_to_set, ArrayBuffer::Order::SeqCst, true);
+    return value_to_set;
+}
+
 // 25.4.11 Atomics.sub ( typedArray, index, value ), https://tc39.es/ecma262/#sec-atomics.sub
 JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::sub)
 {

Userland/Libraries/LibJS/Runtime/AtomicsObject.h

@@ -23,6 +23,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(and_);
     JS_DECLARE_NATIVE_FUNCTION(load);
     JS_DECLARE_NATIVE_FUNCTION(or_);
+    JS_DECLARE_NATIVE_FUNCTION(store);
     JS_DECLARE_NATIVE_FUNCTION(sub);
     JS_DECLARE_NATIVE_FUNCTION(xor_);
 };

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -306,6 +306,7 @@ namespace JS {
     P(sqrt)                                  \
     P(startsWith)                            \
     P(sticky)                                \
+    P(store)                                 \
     P(strike)                                \
     P(stringify)                             \
     P(sub)                                   \

Userland/Libraries/LibJS/Tests/builtins/Atomics/Atomics.store.js

@@ -0,0 +1,60 @@
+test("invariants", () => {
+    expect(Atomics.store).toHaveLength(3);
+});
+
+test("error cases", () => {
+    expect(() => {
+        Atomics.store("not an array", 0);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const bad_array_type = new Float32Array(4);
+        Atomics.store(bad_array_type, 0);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const bad_array_type = new Uint8ClampedArray(4);
+        Atomics.store(bad_array_type, 0);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const array = new Int32Array(4);
+        Atomics.store(array, 100);
+    }).toThrow(RangeError);
+});
+
+test("basic functionality (non-BigInt)", () => {
+    [Int8Array, Int16Array, Int32Array, Uint8Array, Uint16Array, Uint32Array].forEach(ArrayType => {
+        const array = new ArrayType(4);
+
+        expect(Atomics.store(array, 0, 1)).toBe(1);
+        expect(array[0]).toBe(1);
+
+        expect(Atomics.store(array, 1, 2)).toBe(2);
+        expect(array[1]).toBe(2);
+
+        expect(Atomics.store(array, 2, 3)).toBe(3);
+        expect(array[2]).toBe(3);
+
+        expect(Atomics.store(array, 3, 4)).toBe(4);
+        expect(array[3]).toBe(4);
+    });
+});
+
+test("basic functionality (BigInt)", () => {
+    [BigInt64Array, BigUint64Array].forEach(ArrayType => {
+        const array = new ArrayType(4);
+
+        expect(Atomics.store(array, 0, 1n)).toBe(1n);
+        expect(array[0]).toBe(1n);
+
+        expect(Atomics.store(array, 1, 2n)).toBe(2n);
+        expect(array[1]).toBe(2n);
+
+        expect(Atomics.store(array, 2, 3n)).toBe(3n);
+        expect(array[2]).toBe(3n);
+
+        expect(Atomics.store(array, 3, 4n)).toBe(4n);
+        expect(array[3]).toBe(4n);
+    });
+});