Make use of ArrayObjects in favor of generic JS objects.

ArrayObjects has been a thing for years but been under-used. About time
they are used where prudent.

5 files changed, 11 insertions, 14 deletions

diff --git a/js/src/vm/JSONParser.cpp b/js/src/vm/JSONParser.cpp
index 01883bb15..e50da3bc4 100644
--- a/js/src/vm/JSONParser.cpp
+++ b/js/src/vm/JSONParser.cpp
@@ -606,8 +606,8 @@ JSONParserBase::finishArray(MutableHandleValue vp, ElementVector& elements)
 {
     MOZ_ASSERT(&elements == &stack.back().elements());
 
-    JSObject* obj = ObjectGroup::newArrayObject(cx, elements.begin(), elements.length(),
-                                                GenericObject);
+    ArrayObject* obj = ObjectGroup::newArrayObject(cx, elements.begin(), elements.length(),
+                                                   GenericObject);
     if (!obj)
         return false;
 
diff --git a/js/src/vm/ObjectGroup.cpp b/js/src/vm/ObjectGroup.cpp
index a227b7c9c..c2866f5ae 100644
--- a/js/src/vm/ObjectGroup.cpp
+++ b/js/src/vm/ObjectGroup.cpp
@@ -774,7 +774,7 @@ GetValueTypeForTable(const Value& v)
     return type;
 }
 
-/* static */ JSObject*
+/* static */ ArrayObject*
 ObjectGroup::newArrayObject(ExclusiveContext* cx,
                             const Value* vp, size_t length,
                             NewObjectKind newKind, NewArrayKind arrayKind)
@@ -854,11 +854,8 @@ ObjectGroup::newArrayObject(ExclusiveContext* cx,
     }
 
     // The type of the elements being added will already be reflected in type
-    // information, but make sure when creating an unboxed array that the
-    // common element type is suitable for the unboxed representation.
+    // information.
     ShouldUpdateTypes updateTypes = ShouldUpdateTypes::DontUpdate;
-    if (!MaybeAnalyzeBeforeCreatingLargeArray(cx, group, vp, length))
-        return nullptr;
     if (group->maybePreliminaryObjects())
         group->maybePreliminaryObjects()->maybeAnalyze(cx, group);
 
diff --git a/js/src/vm/ObjectGroup.h b/js/src/vm/ObjectGroup.h
index 4e24de9f1..553cb8366 100644
--- a/js/src/vm/ObjectGroup.h
+++ b/js/src/vm/ObjectGroup.h
@@ -505,11 +505,11 @@ class ObjectGroup : public gc::TenuredCell
         UnknownIndex  // Make an array with an unknown element type.
     };
 
-    // Create an ArrayObject or UnboxedArrayObject with the specified elements
-    // and a group specialized for the elements.
-    static JSObject* newArrayObject(ExclusiveContext* cx, const Value* vp, size_t length,
-                                    NewObjectKind newKind,
-                                    NewArrayKind arrayKind = NewArrayKind::Normal);
+    // Create an ArrayObject with the specified elements and a group specialized
+    // for the elements.
+    static ArrayObject* newArrayObject(ExclusiveContext* cx, const Value* vp, size_t length,
+                                       NewObjectKind newKind,
+                                       NewArrayKind arrayKind = NewArrayKind::Normal);
 
     // Create a PlainObject or UnboxedPlainObject with the specified properties
     // and a group specialized for those properties.
diff --git a/js/src/vm/Stack.cpp b/js/src/vm/Stack.cpp
index 87e95c893..c5f2cf5f3 100644
--- a/js/src/vm/Stack.cpp
+++ b/js/src/vm/Stack.cpp
@@ -82,7 +82,7 @@ InterpreterFrame::isNonGlobalEvalFrame() const
     return isEvalFrame() && script()->bodyScope()->as<EvalScope>().isNonGlobal();
 }
 
-JSObject*
+ArrayObject*
 InterpreterFrame::createRestParameter(JSContext* cx)
 {
     MOZ_ASSERT(script()->hasRest());
diff --git a/js/src/vm/Stack.h b/js/src/vm/Stack.h
index 552738d89..dc9306c99 100644
--- a/js/src/vm/Stack.h
+++ b/js/src/vm/Stack.h
@@ -523,7 +523,7 @@ class InterpreterFrame
     ArgumentsObject& argsObj() const;
     void initArgsObj(ArgumentsObject& argsobj);
 
-    JSObject* createRestParameter(JSContext* cx);
+    ArrayObject* createRestParameter(JSContext* cx);
 
     /*
      * Environment chain