LibJS: Remove unused target field from Completion

This shrinks Completion by 16 bytes, which has non-trivial impact
on performance.

Userland/Libraries/LibJS/Bytecode/Interpreter.cpp

@@ -1819,7 +1819,7 @@ ThrowCompletionOr<void> IteratorClose::execute_impl(Bytecode::Interpreter& inter
     auto& iterator = verify_cast<IteratorRecord>(interpreter.get(m_iterator_record).as_object());
 
     // FIXME: Return the value of the resulting completion. (Note that m_completion_value can be empty!)
-    TRY(iterator_close(vm, iterator, Completion { m_completion_type, m_completion_value, {} }));
+    TRY(iterator_close(vm, iterator, Completion { m_completion_type, m_completion_value }));
     return {};
 }
 
@@ -1829,7 +1829,7 @@ ThrowCompletionOr<void> AsyncIteratorClose::execute_impl(Bytecode::Interpreter&
     auto& iterator = verify_cast<IteratorRecord>(interpreter.get(m_iterator_record).as_object());
 
     // FIXME: Return the value of the resulting completion. (Note that m_completion_value can be empty!)
-    TRY(async_iterator_close(vm, iterator, Completion { m_completion_type, m_completion_value, {} }));
+    TRY(async_iterator_close(vm, iterator, Completion { m_completion_type, m_completion_value }));
     return {};
 }
 

Userland/Libraries/LibJS/Runtime/ArrayConstructor.cpp

@@ -403,7 +403,7 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from_async)
                     TRY(array->set(vm.names.length, Value(k), Object::ShouldThrowExceptions::Yes));
 
                     // b. Return Completion Record { [[Type]]: return, [[Value]]: A, [[Target]]: empty }.
-                    return Completion { Completion::Type::Return, array, {} };
+                    return Completion { Completion::Type::Return, array };
                 }
 
                 // 8. Let nextValue be ? IteratorValue(nextResult).
@@ -508,7 +508,7 @@ JS_DEFINE_NATIVE_FUNCTION(ArrayConstructor::from_async)
             TRY(array->set(vm.names.length, Value(length), Object::ShouldThrowExceptions::Yes));
 
             // ix. Return Completion Record { [[Type]]: return, [[Value]]: A, [[Target]]: empty }.
-            return Completion { Completion::Type::Return, array, {} };
+            return Completion { Completion::Type::Return, array };
         }
     };
 

Userland/Libraries/LibJS/Runtime/AsyncGeneratorPrototype.cpp

@@ -119,7 +119,7 @@ JS_DEFINE_NATIVE_FUNCTION(AsyncGeneratorPrototype::return_)
     auto generator = TRY_OR_REJECT(vm, promise_capability, async_generator_validate(vm, generator_this_value, OptionalNone {}));
 
     // 5. Let completion be Completion Record { [[Type]]: return, [[Value]]: value, [[Target]]: empty }.
-    auto completion = Completion(Completion::Type::Return, vm.argument(0), {});
+    auto completion = Completion(Completion::Type::Return, vm.argument(0));
 
     // 6. Perform AsyncGeneratorEnqueue(generator, completion, promiseCapability).
     generator->async_generator_enqueue(completion, promise_capability);

Userland/Libraries/LibJS/Runtime/Completion.cpp

@@ -144,7 +144,7 @@ Completion throw_completion(Value value)
         log_exception(value);
 
     // 1. Return Completion Record { [[Type]]: throw, [[Value]]: value, [[Target]]: empty }.
-    return { Completion::Type::Throw, value, {} };
+    return { Completion::Type::Throw, value };
 }
 
 }

Userland/Libraries/LibJS/Runtime/Completion.h

@@ -63,10 +63,9 @@ public:
         Throw,
     };
 
-    ALWAYS_INLINE Completion(Type type, Optional<Value> value, Optional<DeprecatedFlyString> target)
+    ALWAYS_INLINE Completion(Type type, Optional<Value> value)
         : m_type(type)
         , m_value(move(value))
-        , m_target(move(target))
     {
         VERIFY(type != Type::Empty);
         if (m_value.has_value())
@@ -78,12 +77,12 @@ public:
     // 5.2.3.1 Implicit Completion Values, https://tc39.es/ecma262/#sec-implicit-completion-values
     // Not `explicit` on purpose.
     ALWAYS_INLINE Completion(Value value)
-        : Completion(Type::Normal, value, {})
+        : Completion(Type::Normal, value)
     {
     }
 
     ALWAYS_INLINE Completion(Optional<Value> value)
-        : Completion(Type::Normal, move(value), {})
+        : Completion(Type::Normal, move(value))
     {
     }
 
@@ -104,8 +103,6 @@ public:
     }
     [[nodiscard]] Optional<Value>& value() { return m_value; }
     [[nodiscard]] Optional<Value> const& value() const { return m_value; }
-    [[nodiscard]] Optional<DeprecatedFlyString>& target() { return m_target; }
-    [[nodiscard]] Optional<DeprecatedFlyString> const& target() const { return m_target; }
 
     // "abrupt completion refers to any completion with a [[Type]] value other than normal"
     [[nodiscard]] bool is_abrupt() const { return m_type != Type::Normal; }
@@ -117,7 +114,7 @@ public:
     {
         VERIFY(is_error());
         VERIFY(m_value.has_value());
-        return { m_type, release_value(), move(m_target) };
+        return { m_type, release_value() };
     }
 
     // 6.2.3.4 UpdateEmpty ( completionRecord, value ), https://tc39.es/ecma262/#sec-updateempty
@@ -132,7 +129,7 @@ public:
             return *this;
 
         // 3. Return Completion Record { [[Type]]: completionRecord.[[Type]], [[Value]]: value, [[Target]]: completionRecord.[[Target]] }.
-        return { m_type, move(value), m_target };
+        return { m_type, move(value) };
     }
 
 private:
@@ -150,9 +147,9 @@ private:
         return m_type == Type::Empty;
     }
 
-    Type m_type { Type::Normal };           // [[Type]]
+    Type m_type { Type::Normal }; // [[Type]]
-    Optional<Value> m_value;                // [[Value]]
+    Optional<Value> m_value;      // [[Value]]
-    Optional<DeprecatedFlyString> m_target; // [[Target]]
+    // NOTE: We don't need the [[Target]] slot since control flow is handled in bytecode.
 };
 
 }
@@ -354,7 +351,7 @@ ThrowCompletionOr<Value> await(VM&, Value);
 inline Completion normal_completion(Optional<Value> value)
 {
     // 1. Return Completion Record { [[Type]]: normal, [[Value]]: value, [[Target]]: empty }.
-    return { Completion::Type::Normal, move(value), {} };
+    return { Completion::Type::Normal, move(value) };
 }
 
 // 6.2.4.2 ThrowCompletion ( value ), https://tc39.es/ecma262/#sec-throwcompletion

Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp

@@ -1247,7 +1247,7 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
         if (declaration_result.is_throw_completion()) {
             auto promise_capability = MUST(new_promise_capability(vm, realm.intrinsics().promise_constructor()));
             MUST(call(vm, *promise_capability->reject(), js_undefined(), *declaration_result.throw_completion().value()));
-            return Completion { Completion::Type::Return, promise_capability->promise(), {} };
+            return Completion { Completion::Type::Return, promise_capability->promise() };
         }
     }
 
@@ -1261,11 +1261,11 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
     // NOTE: Running the bytecode should eventually return a completion.
     // Until it does, we assume "return" and include the undefined fallback from the call site.
     if (m_kind == FunctionKind::Normal)
-        return { Completion::Type::Return, result.value_or(js_undefined()), {} };
+        return { Completion::Type::Return, result.value_or(js_undefined()) };
 
     if (m_kind == FunctionKind::AsyncGenerator) {
         auto async_generator_object = TRY(AsyncGenerator::create(realm, result, this, vm.running_execution_context().copy()));
-        return { Completion::Type::Return, async_generator_object, {} };
+        return { Completion::Type::Return, async_generator_object };
     }
 
     auto generator_object = TRY(GeneratorObject::create(realm, result, this, vm.running_execution_context().copy()));
@@ -1273,10 +1273,10 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
     // NOTE: Async functions are entirely transformed to generator functions, and wrapped in a custom driver that returns a promise
     //       See AwaitExpression::generate_bytecode() for the transformation.
     if (m_kind == FunctionKind::Async)
-        return { Completion::Type::Return, AsyncFunctionDriverWrapper::create(realm, generator_object), {} };
+        return { Completion::Type::Return, AsyncFunctionDriverWrapper::create(realm, generator_object) };
 
     VERIFY(m_kind == FunctionKind::Generator);
-    return { Completion::Type::Return, generator_object, {} };
+    return { Completion::Type::Return, generator_object };
 }
 
 void ECMAScriptFunctionObject::set_name(DeprecatedFlyString const& name)

Userland/Libraries/LibJS/Runtime/GeneratorPrototype.cpp

@@ -44,7 +44,7 @@ JS_DEFINE_NATIVE_FUNCTION(GeneratorPrototype::return_)
     auto generator_object = TRY(typed_this_object(vm));
 
     // 2. Let C be Completion Record { [[Type]]: return, [[Value]]: value, [[Target]]: empty }.
-    auto completion = Completion(Completion::Type::Return, vm.argument(0), {});
+    auto completion = Completion(Completion::Type::Return, vm.argument(0));
 
     // 3. Return ? GeneratorResumeAbrupt(g, C, empty).
     return generator_object->resume_abrupt(vm, completion, {});

Userland/Libraries/LibJS/Runtime/IteratorHelperPrototype.cpp

@@ -62,7 +62,7 @@ JS_DEFINE_NATIVE_FUNCTION(IteratorHelperPrototype::return_)
     }
 
     // 5. Let C be Completion { [[Type]]: return, [[Value]]: undefined, [[Target]]: empty }.
-    Completion completion { Completion::Type::Return, js_undefined(), {} };
+    Completion completion { Completion::Type::Return, js_undefined() };
 
     // 6. Return ? GeneratorResumeAbrupt(O, C, "Iterator Helper").
     return TRY(iterator->resume_abrupt(vm, move(completion), "Iterator Helper"sv));

Userland/Libraries/LibWeb/HTML/Scripting/ClassicScript.cpp

@@ -91,7 +91,7 @@ JS::Completion ClassicScript::run(RethrowErrors rethrow_errors, JS::GCPtr<JS::En
 
     // 5. If script's error to rethrow is not null, then set evaluationStatus to Completion { [[Type]]: throw, [[Value]]: script's error to rethrow, [[Target]]: empty }.
     if (!error_to_rethrow().is_null()) {
-        evaluation_status = JS::Completion { JS::Completion::Type::Throw, error_to_rethrow(), {} };
+        evaluation_status = JS::Completion { JS::Completion::Type::Throw, error_to_rethrow() };
     } else {
         auto timer = Core::ElapsedTimer::start_new();