Merge pull request #1278 from MoonchildProductions/js-modules

Partial solution for JS modules

5 files changed, 68 insertions, 152 deletions

diff --git a/js/src/builtin/Iterator.js b/js/src/builtin/Iterator.js
index 735eec7a0..e25b76156 100644
--- a/js/src/builtin/Iterator.js
+++ b/js/src/builtin/Iterator.js
@@ -84,44 +84,3 @@ function LegacyIteratorShim() {
 function LegacyGeneratorIteratorShim() {
     return NewLegacyIterator(ToObject(this), LegacyGeneratorIterator);
 }
-
-// 7.4.8 CreateListIterator()
-function CreateListIterator(array) {
-    let iterator = NewListIterator();
-    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_TARGET, array);
-    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_NEXT_INDEX, 0);
-
-    // 7.4.8.1 ListIterator next()
-    // The spec requires that we use a new next function per iterator object.
-    let next = function() {
-        if (!IsObject(this) || !IsListIterator(this))
-            return callFunction(CallListIteratorMethodIfWrapped, this, "ListIteratorNext");
-
-        if (ActiveFunction() !== UnsafeGetReservedSlot(this, ITERATOR_SLOT_NEXT_METHOD))
-            ThrowTypeError(JSMSG_INCOMPATIBLE_METHOD, "next", "method", ToString(this));
-
-        let array = UnsafeGetObjectFromReservedSlot(this, ITERATOR_SLOT_TARGET);
-        let index = UnsafeGetReservedSlot(this, ITERATOR_SLOT_NEXT_INDEX);
-
-        if (index >= ToLength(array.length)) {
-            UnsafeSetReservedSlot(this, ITERATOR_SLOT_NEXT_INDEX, 1/0);
-            return { value: undefined, done: true };
-        }
-
-        UnsafeSetReservedSlot(this, ITERATOR_SLOT_NEXT_INDEX, index + 1);
-        return { value: array[index], done: false };
-    };
-
-    UnsafeSetReservedSlot(iterator, ITERATOR_SLOT_NEXT_METHOD, next);
-    iterator.next = next;
-
-    iterator[std_iterator] = ListIteratorIdentity;
-    return iterator;
-}
-
-function ListIteratorIdentity() {
-    if (!IsObject(this) || !IsListIterator(this))
-        return callFunction(CallListIteratorMethodIfWrapped, this, "ListIteratorIdentity");
-
-    return this;
-}
diff --git a/js/src/builtin/Module.js b/js/src/builtin/Module.js
index 7b70a7fe8..5c3d5e147 100644
--- a/js/src/builtin/Module.js
+++ b/js/src/builtin/Module.js
@@ -65,12 +65,12 @@ function ModuleGetExportedNames(exportStarSet = [])
     return exportedNames;
 }
 
-// 15.2.1.16.3 ResolveExport(exportName, resolveSet, exportStarSet)
-function ModuleResolveExport(exportName, resolveSet = [], exportStarSet = [])
+// 15.2.1.16.3 ResolveExport(exportName, resolveSet)
+function ModuleResolveExport(exportName, resolveSet = [])
 {
     if (!IsObject(this) || !IsModule(this)) {
         return callFunction(CallModuleMethodIfWrapped, this, exportName, resolveSet,
-                            exportStarSet, "ModuleResolveExport");
+                            "ModuleResolveExport");
     }
 
     // Step 1
@@ -100,38 +100,29 @@ function ModuleResolveExport(exportName, resolveSet = [], exportStarSet = [])
         let e = indirectExportEntries[i];
         if (exportName === e.exportName) {
             let importedModule = CallModuleResolveHook(module, e.moduleRequest,
-                                                       MODULE_STATE_INSTANTIATED);
-            let indirectResolution = callFunction(importedModule.resolveExport, importedModule,
-                                                  e.importName, resolveSet, exportStarSet);
-            if (indirectResolution !== null)
-                return indirectResolution;
+                                                       MODULE_STATE_PARSED);
+            return callFunction(importedModule.resolveExport, importedModule, e.importName,
+                                resolveSet);
         }
     }
 
     // Step 6
     if (exportName === "default") {
         // A default export cannot be provided by an export *.
-        ThrowSyntaxError(JSMSG_BAD_DEFAULT_EXPORT);
+        return null;
     }
 
     // Step 7
-    if (callFunction(ArrayIncludes, exportStarSet, module))
-        return null;
-
-    // Step 8
-    _DefineDataProperty(exportStarSet, exportStarSet.length, module);
-
-    // Step 9
     let starResolution = null;
 
-    // Step 10
+    // Step 8
     let starExportEntries = module.starExportEntries;
     for (let i = 0; i < starExportEntries.length; i++) {
         let e = starExportEntries[i];
         let importedModule = CallModuleResolveHook(module, e.moduleRequest,
-                                                   MODULE_STATE_INSTANTIATED);
+                                                   MODULE_STATE_PARSED);
         let resolution = callFunction(importedModule.resolveExport, importedModule,
-                                      exportName, resolveSet, exportStarSet);
+                                      exportName, resolveSet);
         if (resolution === "ambiguous")
             return resolution;
 
@@ -148,6 +139,7 @@ function ModuleResolveExport(exportName, resolveSet = [], exportStarSet = [])
         }
     }
 
+    // Step 9
     return starResolution;
 }
 
@@ -213,8 +205,8 @@ function GetModuleEnvironment(module)
 
 function RecordInstantationFailure(module)
 {
-    // Set the module's environment slot to 'null' to indicate a failed module
-    // instantiation.
+    // Set the module's state to 'failed' to indicate a failed module
+    // instantiation and reset the environment slot to 'undefined'.
     assert(IsModule(module), "Non-module passed to RecordInstantationFailure");
     SetModuleState(module, MODULE_STATE_FAILED);
     UnsafeSetReservedSlot(module, MODULE_OBJECT_ENVIRONMENT_SLOT, undefined);
@@ -275,11 +267,13 @@ function ModuleDeclarationInstantiation()
                     ThrowSyntaxError(JSMSG_MISSING_IMPORT, imp.importName);
                 if (resolution === "ambiguous")
                     ThrowSyntaxError(JSMSG_AMBIGUOUS_IMPORT, imp.importName);
+                if (resolution.module.state < MODULE_STATE_INSTANTIATED)
+                    ThrowInternalError(JSMSG_BAD_MODULE_STATE);
                 CreateImportBinding(env, imp.localName, resolution.module, resolution.bindingName);
             }
         }
 
-        // Step 16.iv
+        // Step 17.a.iii
         InstantiateModuleFunctionDeclarations(module);
     } catch (e) {
         RecordInstantationFailure(module);
@@ -318,11 +312,3 @@ function ModuleEvaluation()
     return EvaluateModule(module);
 }
 _SetCanonicalName(ModuleEvaluation, "ModuleEvaluation");
-
-function ModuleNamespaceEnumerate()
-{
-    if (!IsObject(this) || !IsModuleNamespace(this))
-        return callFunction(CallModuleMethodIfWrapped, this, "ModuleNamespaceEnumerate");
-
-    return CreateListIterator(ModuleNamespaceExports(this));
-}
diff --git a/js/src/builtin/ModuleObject.cpp b/js/src/builtin/ModuleObject.cpp
index 798ef46e1..575bab0b0 100644
--- a/js/src/builtin/ModuleObject.cpp
+++ b/js/src/builtin/ModuleObject.cpp
@@ -147,7 +147,7 @@ DEFINE_GETTER_FUNCTIONS(ExportEntryObject, moduleRequest, ModuleRequestSlot)
 DEFINE_GETTER_FUNCTIONS(ExportEntryObject, importName, ImportNameSlot)
 DEFINE_GETTER_FUNCTIONS(ExportEntryObject, localName, LocalNameSlot)
 
-DEFINE_ATOM_ACCESSOR_METHOD(ExportEntryObject, exportName)
+DEFINE_ATOM_OR_NULL_ACCESSOR_METHOD(ExportEntryObject, exportName)
 DEFINE_ATOM_OR_NULL_ACCESSOR_METHOD(ExportEntryObject, moduleRequest)
 DEFINE_ATOM_OR_NULL_ACCESSOR_METHOD(ExportEntryObject, importName)
 DEFINE_ATOM_OR_NULL_ACCESSOR_METHOD(ExportEntryObject, localName)
@@ -289,14 +289,6 @@ ModuleNamespaceObject::create(JSContext* cx, HandleModuleObject module)
     if (!object)
         return nullptr;
 
-    RootedId funName(cx, INTERNED_STRING_TO_JSID(cx, cx->names().Symbol_iterator_fun));
-    RootedFunction enumerateFun(cx);
-    enumerateFun = JS::GetSelfHostedFunction(cx, "ModuleNamespaceEnumerate", funName, 0);
-    if (!enumerateFun)
-        return nullptr;
-
-    SetProxyExtra(object, ProxyHandler::EnumerateFunctionSlot, ObjectValue(*enumerateFun));
-
     return &object->as<ModuleNamespaceObject>();
 }
 
@@ -338,14 +330,9 @@ ModuleNamespaceObject::addBinding(JSContext* cx, HandleAtom exportedName,
 const char ModuleNamespaceObject::ProxyHandler::family = 0;
 
 ModuleNamespaceObject::ProxyHandler::ProxyHandler()
-  : BaseProxyHandler(&family, true)
+  : BaseProxyHandler(&family, false)
 {}
 
-JS::Value ModuleNamespaceObject::ProxyHandler::getEnumerateFunction(HandleObject proxy) const
-{
-    return GetProxyExtra(proxy, EnumerateFunctionSlot);
-}
-
 bool
 ModuleNamespaceObject::ProxyHandler::getPrototype(JSContext* cx, HandleObject proxy,
                                                   MutableHandleObject protop) const
@@ -358,6 +345,8 @@ bool
 ModuleNamespaceObject::ProxyHandler::setPrototype(JSContext* cx, HandleObject proxy,
                                                   HandleObject proto, ObjectOpResult& result) const
 {
+    if (!proto)
+        return result.succeed();
     return result.failCantSetProto();
 }
 
@@ -402,21 +391,12 @@ ModuleNamespaceObject::ProxyHandler::getOwnPropertyDescriptor(JSContext* cx, Han
     Rooted<ModuleNamespaceObject*> ns(cx, &proxy->as<ModuleNamespaceObject>());
     if (JSID_IS_SYMBOL(id)) {
         Rooted<JS::Symbol*> symbol(cx, JSID_TO_SYMBOL(id));
-        if (symbol == cx->wellKnownSymbols().iterator) {
-            RootedValue enumerateFun(cx, getEnumerateFunction(proxy));
-            desc.object().set(proxy);
-            desc.setConfigurable(false);
-            desc.setEnumerable(false);
-            desc.setValue(enumerateFun);
-            return true;
-        }
-
         if (symbol == cx->wellKnownSymbols().toStringTag) {
             RootedValue value(cx, StringValue(cx->names().Module));
             desc.object().set(proxy);
             desc.setWritable(false);
             desc.setEnumerable(false);
-            desc.setConfigurable(true);
+            desc.setConfigurable(false);
             desc.setValue(value);
             return true;
         }
@@ -458,8 +438,8 @@ ModuleNamespaceObject::ProxyHandler::has(JSContext* cx, HandleObject proxy, Hand
     Rooted<ModuleNamespaceObject*> ns(cx, &proxy->as<ModuleNamespaceObject>());
     if (JSID_IS_SYMBOL(id)) {
         Rooted<JS::Symbol*> symbol(cx, JSID_TO_SYMBOL(id));
-        return symbol == cx->wellKnownSymbols().iterator ||
-               symbol == cx->wellKnownSymbols().toStringTag;
+        *bp = symbol == cx->wellKnownSymbols().toStringTag;
+        return true;
     }
 
     *bp = ns->bindings().has(id);
@@ -473,23 +453,21 @@ ModuleNamespaceObject::ProxyHandler::get(JSContext* cx, HandleObject proxy, Hand
     Rooted<ModuleNamespaceObject*> ns(cx, &proxy->as<ModuleNamespaceObject>());
     if (JSID_IS_SYMBOL(id)) {
         Rooted<JS::Symbol*> symbol(cx, JSID_TO_SYMBOL(id));
-        if (symbol == cx->wellKnownSymbols().iterator) {
-            vp.set(getEnumerateFunction(proxy));
-            return true;
-        }
-
         if (symbol == cx->wellKnownSymbols().toStringTag) {
             vp.setString(cx->names().Module);
             return true;
         }
 
-        return false;
+        vp.setUndefined();
+        return true;
     }
 
     ModuleEnvironmentObject* env;
     Shape* shape;
-    if (!ns->bindings().lookup(id, &env, &shape))
-        return false;
+    if (!ns->bindings().lookup(id, &env, &shape)) {
+        vp.setUndefined();
+        return true;
+    }
 
     RootedValue value(cx, env->getSlot(shape->slot()));
     if (value.isMagic(JS_UNINITIALIZED_LEXICAL)) {
@@ -526,7 +504,7 @@ ModuleNamespaceObject::ProxyHandler::ownPropertyKeys(JSContext* cx, HandleObject
     Rooted<ModuleNamespaceObject*> ns(cx, &proxy->as<ModuleNamespaceObject>());
     RootedObject exports(cx, &ns->exports());
     uint32_t count;
-    if (!GetLengthProperty(cx, exports, &count) || !props.reserve(props.length() + count))
+    if (!GetLengthProperty(cx, exports, &count) || !props.reserve(props.length() + count + 1))
         return false;
 
     Rooted<ValueVector> names(cx, ValueVector(cx));
@@ -536,6 +514,8 @@ ModuleNamespaceObject::ProxyHandler::ownPropertyKeys(JSContext* cx, HandleObject
     for (uint32_t i = 0; i < count; i++)
         props.infallibleAppend(AtomToId(&names[i].toString()->asAtom()));
 
+    props.infallibleAppend(SYMBOL_TO_JSID(cx->wellKnownSymbols().toStringTag));
+
     return true;
 }
 
@@ -1014,7 +994,7 @@ GlobalObject::initModuleProto(JSContext* cx, Handle<GlobalObject*> global)
 
     static const JSFunctionSpec protoFunctions[] = {
         JS_SELF_HOSTED_FN("getExportedNames", "ModuleGetExportedNames", 1, 0),
-        JS_SELF_HOSTED_FN("resolveExport", "ModuleResolveExport", 3, 0),
+        JS_SELF_HOSTED_FN("resolveExport", "ModuleResolveExport", 2, 0),
         JS_SELF_HOSTED_FN("declarationInstantiation", "ModuleDeclarationInstantiation", 0, 0),
         JS_SELF_HOSTED_FN("evaluation", "ModuleEvaluation", 0, 0),
         JS_FS_END
@@ -1164,6 +1144,13 @@ ModuleBuilder::processExport(frontend::ParseNode* pn)
     bool isDefault = pn->getKind() == PNK_EXPORT_DEFAULT;
     ParseNode* kid = isDefault ? pn->pn_left : pn->pn_kid;
 
+    if (isDefault && pn->pn_right) {
+        // This is an export default containing an expression.
+        RootedAtom localName(cx_, cx_->names().starDefaultStar);
+        RootedAtom exportName(cx_, cx_->names().default_);
+        return appendExportEntry(exportName, localName);
+    }
+
     switch (kid->getKind()) {
       case PNK_EXPORT_SPEC_LIST:
         MOZ_ASSERT(!isDefault);
@@ -1177,53 +1164,46 @@ ModuleBuilder::processExport(frontend::ParseNode* pn)
         break;
 
       case PNK_CLASS: {
-          const ClassNode& cls = kid->as<ClassNode>();
-          MOZ_ASSERT(cls.names());
-          RootedAtom localName(cx_, cls.names()->innerBinding()->pn_atom);
-          RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
-          if (!appendExportEntry(exportName, localName))
-              return false;
-          break;
+        const ClassNode& cls = kid->as<ClassNode>();
+        MOZ_ASSERT(cls.names());
+        RootedAtom localName(cx_, cls.names()->innerBinding()->pn_atom);
+        RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
+        if (!appendExportEntry(exportName, localName))
+            return false;
+        break;
       }
 
       case PNK_VAR:
       case PNK_CONST:
       case PNK_LET: {
-          MOZ_ASSERT(kid->isArity(PN_LIST));
-          for (ParseNode* var = kid->pn_head; var; var = var->pn_next) {
-              if (var->isKind(PNK_ASSIGN))
-                  var = var->pn_left;
-              MOZ_ASSERT(var->isKind(PNK_NAME));
-              RootedAtom localName(cx_, var->pn_atom);
-              RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
-              if (!appendExportEntry(exportName, localName))
-                  return false;
-          }
-          break;
+        MOZ_ASSERT(kid->isArity(PN_LIST));
+        for (ParseNode* var = kid->pn_head; var; var = var->pn_next) {
+            if (var->isKind(PNK_ASSIGN))
+                var = var->pn_left;
+            MOZ_ASSERT(var->isKind(PNK_NAME));
+            RootedAtom localName(cx_, var->pn_atom);
+            RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
+            if (!appendExportEntry(exportName, localName))
+                return false;
+        }
+        break;
       }
 
       case PNK_FUNCTION: {
-          RootedFunction func(cx_, kid->pn_funbox->function());
-          if (!func->isArrow()) {
-              RootedAtom localName(cx_, func->explicitName());
-              RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
-              MOZ_ASSERT_IF(isDefault, localName);
-              if (!appendExportEntry(exportName, localName))
-                  return false;
-              break;
-          }
-      }
-
-      MOZ_FALLTHROUGH; // Arrow functions are handled below.
-
-      default:
-        MOZ_ASSERT(isDefault);
-        RootedAtom localName(cx_, cx_->names().starDefaultStar);
-        RootedAtom exportName(cx_, cx_->names().default_);
+        RootedFunction func(cx_, kid->pn_funbox->function());
+        MOZ_ASSERT(!func->isArrow());
+        RootedAtom localName(cx_, func->explicitName());
+        RootedAtom exportName(cx_, isDefault ? cx_->names().default_ : localName.get());
+        MOZ_ASSERT_IF(isDefault, localName);
         if (!appendExportEntry(exportName, localName))
             return false;
         break;
+      }
+
+      default:
+        MOZ_CRASH("Unexpected parse node");
     }
+
     return true;
 }
 
diff --git a/js/src/builtin/ModuleObject.h b/js/src/builtin/ModuleObject.h
index e83520ebe..22db762ac 100644
--- a/js/src/builtin/ModuleObject.h
+++ b/js/src/builtin/ModuleObject.h
@@ -142,15 +142,8 @@ class ModuleNamespaceObject : public ProxyObject
   private:
     struct ProxyHandler : public BaseProxyHandler
     {
-        enum
-        {
-            EnumerateFunctionSlot = 0
-        };
-
         ProxyHandler();
 
-        JS::Value getEnumerateFunction(HandleObject proxy) const;
-
         bool getOwnPropertyDescriptor(JSContext* cx, HandleObject proxy, HandleId id,
                                       MutableHandle<PropertyDescriptor> desc) const override;
         bool defineProperty(JSContext* cx, HandleObject proxy, HandleId id,
diff --git a/js/src/builtin/SelfHostingDefines.h b/js/src/builtin/SelfHostingDefines.h
index b57c17269..d676270a1 100644
--- a/js/src/builtin/SelfHostingDefines.h
+++ b/js/src/builtin/SelfHostingDefines.h
@@ -71,8 +71,6 @@
 // Used for list, i.e. Array and String, iterators.
 #define ITERATOR_SLOT_NEXT_INDEX 1
 #define ITERATOR_SLOT_ITEM_KIND 2
-// Used for ListIterator.
-#define ITERATOR_SLOT_NEXT_METHOD 2
 
 #define ITEM_KIND_KEY 0
 #define ITEM_KIND_VALUE 1