[js-api] Extend with reference types support. (WebAssembly#79)

* [js-api] Remove spurious argument to ToWebAssemblyValue().

Fixes WebAssembly#51.

* [js-api] Extend the WebAssembly.Table API.

Fixes WebAssembly#22.
Fixes WebAssembly#67.

Author: Ms2ger

document/js-api/index.bs

@@ -722,10 +722,10 @@ dictionary TableDescriptor {
 
 [LegacyNamespace=WebAssembly, Exposed=(Window,Worker,Worklet)]
 interface Table {
-  constructor(TableDescriptor descriptor);
-  unsigned long grow([EnforceRange] unsigned long delta);
-  Function? get([EnforceRange] unsigned long index);
-  void set([EnforceRange] unsigned long index, Function? value);
+  constructor(TableDescriptor descriptor, optional any value);
+  unsigned long grow([EnforceRange] unsigned long delta, optional any value);
+  any get([EnforceRange] unsigned long index);
+  void set([EnforceRange] unsigned long index, optional any value);
   readonly attribute unsigned long length;
 };
 </pre>
@@ -736,7 +736,7 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
 {{Table}} object has the following internal slots:
 
     * \[[Table]] : a [=table address=]
-    * \[[Values]] : a [=list=] whose elements are either null or [=Exported Function=]s.
+    * \[[Values]] : a [=list=] whose elements depend on the element type of \[[Table]]'s [=table type=].
 </div>
 
 <div algorithm>
@@ -761,29 +761,41 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
 </div>
 
 <div algorithm>
-    The <dfn constructor for="Table">Table(|descriptor|)</dfn> constructor, when invoked, performs the following steps:
+    The <dfn constructor for="Table">Table(|descriptor|, |value|)</dfn> constructor, when invoked, performs the following steps:
+    1. Let |elementType| be ToValueType(descriptor|["element"]).
     1. let |initial| be |descriptor|["initial"].
     1. If |descriptor|["maximum"] is [=present=], let |maximum| be |descriptor|["maximum"]; otherwise, let |maximum| be empty.
     1. If |maximum| is not empty and |maximum| &lt; |initial|, throw a {{RangeError}} exception.
-    1. Let |type| be the [=table type=] {[=table type|𝗆𝗂𝗇=] n, [=table type|𝗆𝖺𝗑=] |maximum|} [=table type|funcref=].
+    1. If |value| is missing,
+        1. Let |ref| be [=DefaultValue=](|elementType|).
+    1. Otherwise,
+        1. Let |ref| be ? [=ToWebAssemblyValue=](|value|, |elementType|).
+    1. Let |type| be the [=table type=] {[=table type|𝗆𝗂𝗇=] |initial|, [=table type|𝗆𝖺𝗑=] |maximum|} |elementType|.
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
-    1. Let (|store|, |tableaddr|) be [=table_alloc=](|store|, |type|, [=ref.null=]). <!-- TODO(littledan): Report allocation failure https://github.com/WebAssembly/spec/issues/584 -->
+    1. Let (|store|, |tableaddr|) be [=table_alloc=](|store|, |type|, |ref|). <!-- TODO(littledan): Report allocation failure https://github.com/WebAssembly/spec/issues/584 -->
     1. Set the [=surrounding agent=]'s [=associated store=] to |store|.
     1. [=initialize a table object|Initialize=] **this** from |tableaddr|.
+    1. [=list/Empty=] **this**.\[[Values]].
+    1. [=list/Append=] |value| to **this**.\[[Values]] |initial| times.
 </div>
 
 <div algorithm=dom-Table-grow>
-    The <dfn method for="Table">grow(|delta|)</dfn> method, when invoked, performs the following steps:
+    The <dfn method for="Table">grow(|delta|, |value|)</dfn> method, when invoked, performs the following steps:
     1. Let |tableaddr| be **this**.\[[Table]].
     1. Let |initialSize| be the length of **this**.\[[Values]].
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
-    1. Let |result| be [=table_grow=](|store|, |tableaddr|, |delta|, [=ref.null=]).
+    1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|tableaddr|).
+    1. If |value| is missing,
+        1. Let |ref| be [=DefaultValue=](|elementType|).
+    1. Otherwise,
+        1. Let |ref| be ? [=ToWebAssemblyValue=](|value|, |elementType|).
+    1. Let |result| be [=table_grow=](|store|, |tableaddr|, |delta|, |ref|).
     1. If |result| is [=error=], throw a {{RangeError}} exception.
 
         Note: The above exception may happen due to either insufficient memory or an invalid size parameter.
 
     1. Set the [=surrounding agent=]'s [=associated store=] to |result|.
-    1. [=list/Append=] null to **this**.\[[Values]] |delta| times.
+    1. [=list/Append=] |value| to **this**.\[[Values]] |delta| times.
     1. Return |initialSize|.
 </div>
 
@@ -803,10 +815,11 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
     The <dfn method for="Table">set(|index|, |value|)</dfn> method, when invoked, performs the following steps:
     1. Let |tableaddr| be **this**.\[[Table]].
     1. Let |values| be **this**.\[[Values]].
-    1. If |value| is null, let |ref| be [=ref.null=].
+    1. Let (<var ignore>limits</var>, |elementType|) be [=table_type=](|tableaddr|).
+    1. If |value| is missing,
+        1. Let |ref| be [=DefaultValue=](|elementType|).
     1. Otherwise,
-        1. If |value| does not have a \[[FunctionAddress]] internal slot, throw a {{TypeError}} exception.
-        1. Let |ref| be [=ref.func=] |value|.\[[FunctionAddress]].
+        1. Let |ref| be ? [=ToWebAssemblyValue=](|value|, |elementType|).
     1. Let |store| be the [=surrounding agent=]'s [=associated store=].
     1. Let |store| be [=table_write=](|store|, |tableaddr|, |index|, |ref|).
     1. If |store| is [=error=], throw a {{RangeError}} exception.
@@ -822,7 +835,10 @@ enum ValueType {
   "i32",
   "i64",
   "f32",
-  "f64"
+  "f64",
+  "nullref",
+  "anyref",
+  "anyfunc",
 };
 </pre>
 
@@ -886,14 +902,17 @@ which can be simultaneously referenced by multiple {{Instance}} objects. Each
     1. If |valuetype| equals [=𝗂𝟨𝟦=], return [=𝗂𝟨𝟦.𝖼𝗈𝗇𝗌𝗍=] 0.
     1. If |valuetype| equals [=𝖿𝟥𝟤=], return [=𝖿𝟥𝟤.𝖼𝗈𝗇𝗌𝗍=] 0.
     1. If |valuetype| equals [=𝖿𝟨𝟦=], return [=𝖿𝟨𝟦.𝖼𝗈𝗇𝗌𝗍=] 0.
-    1. Else, return [=ref.null=].
+    1. If |valuetype| equals [=nullref=], return [=ref.null=].
+    1. If |valuetype| equals [=anyref=], return [=ToWebAssemblyValue=](undefined, |valuetype|).
+    1. If |valuetype| equals [=nullref=], return [=ref.null=].
+    1. Assert: This step is not reached.
 </div>
 
 <div algorithm>
     The <dfn constructor for="Global">Global(|descriptor|, |v|)</dfn> constructor, when invoked, performs the following steps:
     1. Let |mutable| be |descriptor|["mutable"].
     1. Let |valuetype| be [=ToValueType=](|descriptor|["value"]).
-    1. If |v| is undefined,
+    1. If |v| is missing,
         1. let |value| be [=DefaultValue=](|valuetype|).
     1. Otherwise,
         1. If |valuetype| is [=𝗂𝟨𝟦=], throw a {{TypeError}} exception.
@@ -993,7 +1012,7 @@ This slot holds a [=function address=] relative to the [=surrounding agent=]'s [
     1. For each type |t| of |parameters|,
         1. If the length of |argValues| &gt; |i|, let |arg| be |argValues|[|i|].
         1. Otherwise, let |arg| be undefined.
-        1. [=list/Append=] [=ToWebAssemblyValue=](|arg|, |t|, {{TypeError}}) to |args|.
+        1. [=list/Append=] [=ToWebAssemblyValue=](|arg|, |t|) to |args|.
         1. Set |i| to |i| + 1.
     1. Let |argsSeq| be a WebAssembly [=sequence=] containing the elements of |args|.
     1. Let (|store|, |ret|) be the result of [=func_invoke=](|store|, |funcaddr|, |argsSeq|).
@@ -1060,7 +1079,7 @@ Note: Number values which are equal to NaN may have various observable NaN paylo
 </div>
 
 <div algorithm>
-The algorithm <dfn>ToWebAssemblyValue</dfn>(|v|, |type|, |error|) coerces a JavaScript value to a [=WebAssembly value=]  performs the following steps:
+The algorithm <dfn>ToWebAssemblyValue</dfn>(|v|, |type|) coerces a JavaScript value to a [=WebAssembly value=]  performs the following steps:
 
 
 1. Assert: |type| is not [=𝗂𝟨𝟦=].
@@ -1077,9 +1096,9 @@ The algorithm <dfn>ToWebAssemblyValue</dfn>(|v|, |type|, |error|) coerces a Java
 1. If |type| is [=anyref=],
     1. Do nothing.
 1. If |type| is [=funcref=],
-    1. If |v| is not an [=Exported function=] or null, throw |error|.
+    1. If |v| is not an [=Exported function=] or null, throw a {{TypeError}}.
 1. If |type| is [=nullref=],
-    1. If |v| is not null, throw |error|.
+    1. If |v| is not null, throw a {{TypeError}}.
 1. Return the result of [=allocating a host address=] for |v|.
 
 </div>