Remove unused AO and add SharedArray constructor

spec/index.html

@@ -84,7 +84,9 @@ <h1>
         1. If _constructor_.[[ConstructorKind]] is ~derived~, then
           1. Let _parent_ be ! _constructor_.[[GetPrototypeOf]]().
           1. Perform InitializeStructInstanceFieldsAndBrand(_receiver_, _parent_).
-        1. Prepend _constructor_.[[StructBrand]] to _receiver_.[[StructBrands]].
+        1. If _constructor_ has a [[StructBrand]] internal slot, then
+          1. Prepend _constructor_.[[StructBrand]] to _receiver_.[[StructBrands]].
+          1. NOTE: Shared Struct constructors do not have a [[StructBrand]] internal slot because per-Realm prototypes is currently an open design question and are not included in this draft. Without per-Realm prototypes, Shared Structs cannot have methods, and there are no users of Shared Struct brands.
         1. Let _methods_ be the value of _constructor_.[[PrivateMethods]].
         1. For each PrivateElement _method_ of _methods_, do
           1. Perform ! PrivateMethodOrAccessorAdd(_receiver_, _method_).
@@ -174,7 +176,7 @@ <h1>
           1. If _superclass_ is *null*, then
             1. Let _protoParent_ be *null*.
             1. Let _constructorParent_ be %Function.prototype%.
-          1. Else if _superclass_ does not have a [[IsStructConstructor]] internal field, then
+          1. Else if _superclass_ does not have a [[IsStructConstructor]] internal slot, then
             1. Throw a *TypeError* exception.
           1. Else,
             1. Let _protoParent_ be ? Get(_superclass_, *"prototype"*).
@@ -369,9 +371,9 @@ <h1>
         1. Let _target_ be _F_.[[BoundTargetMethod]].
         1. Let _homeObject_ be _target_.[[HomeObject]].
         1. Assert: _homeObject_ is not *undefined*.
-        1. Assert: _homeObject_ has a [[StructBrand]] internal field.
+        1. Assert: _homeObject_ has a [[StructBrand]] internal slot.
         1. If _thisArgument_ is not an Object, throw a *TypeError* exception.
-        1. If _thisArgument_ does not have a [[StructBrands]] internal field, throw a *TypeError* exception.
+        1. If _thisArgument_ does not have a [[StructBrands]] internal slot, throw a *TypeError* exception.
         1. If _thisArgument_.[[StructBrands]] does not contain _homeObject_.[[StructBrand]], throw a *TypeError* exception.
         1. Return ? Call(_target_, _thisArgument_, argumentsList_).
       </emu-alg>
@@ -411,7 +413,7 @@ <h1>Runtime Semantics: Evaluation</h1>
           1. Let _func_ be GetSuperConstructor().
           1. Let _argList_ be ? ArgumentListEvaluation of |Arguments|.
           1. If IsConstructor(_func_) is *false*, throw a *TypeError* exception.
-          1. <ins>If _func_ has a [[StructInitializer]] internal field, then</ins>
+          1. <ins>If _func_ has a [[StructInitializer]] internal slot, then</ins>
             1. <ins>If _func_.[[StructInitializer]] is not ~empty~, then</ins>
               1. <ins>Let _envRec_ be GetThisEnvironment().</ins>
               1. <ins>Let _thisValue_ be _envRec_.GetThisBinding().</ins>
@@ -869,28 +871,6 @@ <h1>
       </emu-alg>
     </emu-clause>
 
-    <emu-clause id="sec-initializesharedstructinstancefieldsandbrands" type="abstract operation">
-      <h1>
-        InitializeSharedStructInstanceFieldsAndBrand (
-          _receiver_: an Object,
-          _constructor_: an ECMAScript function object,
-        ): ~unused~
-      </h1>
-      <dl class="header">
-      </dl>
-      <emu-alg>
-        1. Assert: The surrounding agent is in the critical section for Shared Struct creation.
-        1. If _constructor_.[[ConstructorKind]] is ~derived~, then
-          1. Let _parent_ be ! _constructor_.[[GetPrototypeOf]]().
-          1. Perform InitializeSharedStructInstanceFieldsAndBrand(_receiver_, _parent_).
-        1. Prepend _constructor_.[[StructBrand]] to _receiver_.[[StructBrands]].
-        1. Let _fields_ be the value of _constructor_.[[Fields]].
-        1. For each element _fieldRecord_ of _fields_, do
-          1. Perform DefineSharedStructField(_receiver_, _fieldRecord_).
-        1. Return ~unused~.
-      </emu-alg>
-    </emu-clause>
-
     <emu-clause id="sec-runtime-semantics-sharedstructdefinitionevaluation" type="sdo">
       <h1>
         Runtime Semantics: SharedStructDefinitionEvaluation (
@@ -924,7 +904,7 @@ <h1>
           1. Let _superclass_ be ? GetValue(? _superclassRef_).
           1. If _superclass_ is *null*, then
             1. Let _constructorParent_ be %Function.prototype%.
-          1. Else if _superclass_ does not have a [[IsSharedStructConstructor]] internal field, then
+          1. Else if _superclass_ does not have a [[IsSharedStructConstructor]] internal slot, then
             1. Throw a *TypeError* exception.
           1. Else,
             1. Let _constructorParent_ be _superclass_.
@@ -1431,3 +1411,85 @@ <h1>Memory Model Fundamentals</h1>
   </emu-clause>
   <p>For brevity, the refactoring of the memory model relations to use SharedStructStorage and the modified definition of event ranges is omitted.</p>
 </emu-clause>
+
+<emu-clause id="sec-shared-arrays">
+  <h1>Shared Array Object</h1>
+  <p><dfn variant="Shared Array">Shared Arrays</dfn> are a special case of Shared Structs with array indexed properties and an immutable *"length"* own property. Since they are Shared Structs, their layout, i.e. their length, is fixed at creation time.</p>
+
+  <ins class="block">
+  <emu-clause id="sec-shared-array-constructor">
+    <h1>The SharedArray Constructor</h1>
+    <p>The SharedArray constructor:</p>
+    <ul>
+      <li>is <dfn>%SharedArray%</dfn>.</li>
+      <li>is the initial value of the *"SharedArray"* property of the global object.</li>
+      <li>creates and initializes a new Shared Array when called as a constructor.</li>
+      <li>is not intended to be called as a function and will throw an exception when called in that manner.</li>
+      <li>is a function whose behaviour differs based upon the number and types of its arguments.</li>
+    </ul>
+
+    <emu-clause id="sec-sharedarraycreate" type="abstract operation">
+      <h1>
+        SharedArrayCreate (
+          _length_: an non-negative integer,
+        ): a Shared Array
+      </h1>
+      <dl class="header">
+        <dt>description</dt>
+        <dd>It is used to specify the creation of new Shared Arrays.</dd>
+      </dl>
+      <emu-alg>
+        1. Assert: _length_ &le; 2<sup>32</sup> - 1.
+        1. Perform EnterSharedStructCreationCriticalSection().
+        1. Let _A_ be OrdinaryObjectCreate(*null*, « »).
+        1. Set _A_.[[GetOwnProperty]] as specified in <emu-xref href="#sec-shared-struct-getownproperty"></emu-xref>.
+        1. Set _A_.[[DefineOwnProperty]] as specified in <emu-xref href="#sec-shared-struct-defineownproperty"></emu-xref>.
+        1. Set _A_.[[HasProperty]] as specified in <emu-xref href="#sec-shared-struct-hasproperty"></emu-xref>.
+        1. Set _A_.[[Get]] as specified in <emu-xref href="#sec-shared-struct-get"></emu-xref>.
+        1. Set _A_.[[Set]] as specified in <emu-xref href="#sec-shared-struct-set"></emu-xref>.
+        1. Set _A_.[[Delete]] as specified in <emu-xref href="#sec-shared-struct-delete"></emu-xref>.
+        1. Let _k_ be 0.
+        1. Repeat, while _k_ &lt; _length_,
+          1. Let _Pk_ be ! ToString(𝔽(_k_)).
+          1. Create an own data property named _Pk_ of object _A_ whose [[Value]] is *undefined*, [[Writable]] is *true*, [[Enumerable]] is *true*, and [[Configurable]] is *false*.
+          1. Perform WriteSharedStructField(_A_, _Pk_, *undefined*, ~init~).
+        1. Create an own data property named *"length"* of object _A_ whose [[Value]] is 𝔽(_length_), [[Writable]] is *false*, [[Enumerable]] is *false*, and [[Configurable]] is *false*.
+        1. Perform WriteSharedStructField(_A_, *"length"*, 𝔽(_length_), ~init~).
+        1. Perform ! _A_.[[PreventExtensions]]().
+        1. Perform LeaveSharedStructCreationCriticalSection().
+        1. Assert: ! TestIntegrityLevel(_A_, ~sealed~) is *true*.
+        1. Return _A_.
+      </emu-alg>
+    </emu-clause>
+
+    <emu-clause id="sec-sharedarray">
+      <h1>SharedArray ( ..._values_ )</h1>
+      <p>This function performs the following steps when called:</p>
+      <emu-alg>
+        1. If NewTarget is *undefined*, throw a *TypeError* exception.
+        1. EDITOR'S NOTE: Per-Realm prototypes, which is currently an open design question and not included in this draft, will give Shared Arrays a per-Realm prototype with built-in methods.
+        1. Let _numberOfArgs_ be the number of elements in _values_.
+        1. If _numberOfArgs_ = 0, then
+          1. Return SharedArrayCreate(0).
+        1. Else if _numberOfArgs_ = 1, then
+          1. Let _len_ be _values_[0].
+          1. If _len_ is not an integral Number, throw a *TypeError* exception.
+          1. If _len_ &lt; 0, throw a *RangeError* exception.
+          1. Let _lenReal_ be ℝ(_len_).
+          1. If _lenReal_ > 2<sup>32</sup> - 1, throw a *RangeError* exception.
+          1. Return SharedArrayCreate(_lenReal_).
+        1. Else,
+          1. Assert: _numberOfArgs_ ≥ 2.
+          1. Let _array_ be SharedArrayCreate(_numberOfArgs_).
+          1. Let _k_ be 0.
+          1. Repeat, while _k_ &lt; _numberOfArgs_,
+            1. Let _Pk_ be ! ToString(𝔽(_k_)).
+            1. Let _itemK_ be _values_[_k_].
+            1. Perform ! Set(_array_, _Pk_, _itemK_, *true*).
+            1. Set _k_ to _k_ + 1.
+          1. Return _array_.
+      </emu-alg>
+    </emu-clause>
+  </emu-clause>
+  </ins>
+</emu-clause>