LibJS: Implement Atomics.xor

Author: https://github.com/trflynn89
Commit: https://github.com/SerenityOS/serenity/commit/b6364ec8992
Pull-request: https://github.com/SerenityOS/serenity/pull/8656
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/Runtime/AtomicsObject.cpp

@@ -122,6 +122,7 @@ void AtomicsObject::initialize(GlobalObject& global_object)
     define_native_function(vm.names.load, load, 2, attr);
     define_native_function(vm.names.or_, or_, 3, attr);
     define_native_function(vm.names.sub, sub, 3, attr);
+    define_native_function(vm.names.xor_, xor_, 3, attr);
 
     // 25.4.15 Atomics [ @@toStringTag ], https://tc39.es/ecma262/#sec-atomics-@@tostringtag
     define_direct_property(*vm.well_known_symbol_to_string_tag(), js_string(global_object.heap(), "Atomics"), Attribute::Configurable);
@@ -222,4 +223,22 @@ JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::sub)
     VERIFY_NOT_REACHED();
 }
 
+// 25.4.14 Atomics.xor ( typedArray, index, value ), https://tc39.es/ecma262/#sec-atomics.xor
+JS_DEFINE_NATIVE_FUNCTION(AtomicsObject::xor_)
+{
+    auto* typed_array = typed_array_from(global_object, vm.argument(0));
+    if (!typed_array)
+        return {};
+
+    auto atomic_xor = [](auto* storage, auto value) { return AK::atomic_fetch_xor(storage, value); };
+
+#define __JS_ENUMERATE(ClassName, snake_name, PrototypeName, ConstructorName, Type) \
+    if (is<ClassName>(typed_array))                                                 \
+        return perform_atomic_operation<Type>(global_object, *typed_array, move(atomic_xor));
+    JS_ENUMERATE_TYPED_ARRAYS
+#undef __JS_ENUMERATE
+
+    VERIFY_NOT_REACHED();
+}
+
 }

Userland/Libraries/LibJS/Runtime/AtomicsObject.h

@@ -24,6 +24,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(load);
     JS_DECLARE_NATIVE_FUNCTION(or_);
     JS_DECLARE_NATIVE_FUNCTION(sub);
+    JS_DECLARE_NATIVE_FUNCTION(xor_);
 };
 
 }

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -359,6 +359,7 @@ struct CommonPropertyNames {
     PropertyName register_ { "register", PropertyName::StringMayBeNumber::No };
     PropertyName return_ { "return", PropertyName::StringMayBeNumber::No };
     PropertyName throw_ { "throw", PropertyName::StringMayBeNumber::No };
+    PropertyName xor_ { "xor", PropertyName::StringMayBeNumber::No };
 #define __ENUMERATE(x) PropertyName x { #x, PropertyName::StringMayBeNumber::No };
     ENUMERATE_STANDARD_PROPERTY_NAMES(__ENUMERATE)
 #undef __ENUMERATE

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

@@ -0,0 +1,70 @@
+test("invariants", () => {
+    expect(Atomics.xor).toHaveLength(3);
+});
+
+test("error cases", () => {
+    expect(() => {
+        Atomics.xor("not an array", 0, 1);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const bad_array_type = new Float32Array(4);
+        Atomics.xor(bad_array_type, 0, 1);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const bad_array_type = new Uint8ClampedArray(4);
+        Atomics.xor(bad_array_type, 0, 1);
+    }).toThrow(TypeError);
+
+    expect(() => {
+        const array = new Int32Array(4);
+        Atomics.xor(array, 100, 1);
+    }).toThrow(RangeError);
+});
+
+test("basic functionality (non-BigInt)", () => {
+    [Int8Array, Int16Array, Int32Array, Uint8Array, Uint16Array, Uint32Array].forEach(ArrayType => {
+        const array = new ArrayType(2);
+        array[0] = 0b0000;
+        array[1] = 0b0101;
+
+        expect(Atomics.xor(array, 0, 0b0000)).toBe(0b0000);
+        expect(array).toEqual([0b0000, 0b0101]);
+
+        expect(Atomics.xor(array, 0, 0b1111)).toBe(0b0000);
+        expect(array).toEqual([0b1111, 0b0101]);
+
+        expect(Atomics.xor(array, 1, 0b0000)).toBe(0b0101);
+        expect(array).toEqual([0b1111, 0b0101]);
+
+        expect(Atomics.xor(array, 1, 0b0100)).toBe(0b0101);
+        expect(array).toEqual([0b1111, 0b0001]);
+
+        expect(Atomics.xor(array, 1, 0b0001)).toBe(0b0001);
+        expect(array).toEqual([0b1111, 0b0000]);
+    });
+});
+
+test("basic functionality (BigInt)", () => {
+    [BigInt64Array, BigUint64Array].forEach(ArrayType => {
+        const array = new ArrayType(2);
+        array[0] = 0b0000n;
+        array[1] = 0b0101n;
+
+        expect(Atomics.xor(array, 0, 0b0000n)).toBe(0b0000n);
+        expect(array).toEqual([0b0000n, 0b0101n]);
+
+        expect(Atomics.xor(array, 0, 0b1111n)).toBe(0b0000n);
+        expect(array).toEqual([0b1111n, 0b0101n]);
+
+        expect(Atomics.xor(array, 1, 0b0000n)).toBe(0b0101n);
+        expect(array).toEqual([0b1111n, 0b0101n]);
+
+        expect(Atomics.xor(array, 1, 0b0100n)).toBe(0b0101n);
+        expect(array).toEqual([0b1111n, 0b0001n]);
+
+        expect(Atomics.xor(array, 1, 0b0001n)).toBe(0b0001n);
+        expect(array).toEqual([0b1111n, 0b0000n]);
+    });
+});