Revert #1142 - Remove unboxed objects

- accounting for removal of watch()/unwatch()

1 files changed, 319 insertions, 0 deletions

diff --git a/js/src/vm/UnboxedObject.h b/js/src/vm/UnboxedObject.h
new file mode 100644
index 000000000..ba66434bc
--- /dev/null
+++ b/js/src/vm/UnboxedObject.h
@@ -0,0 +1,319 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef vm_UnboxedObject_h
+#define vm_UnboxedObject_h
+
+#include "jsgc.h"
+#include "jsobj.h"
+
+#include "vm/Runtime.h"
+#include "vm/TypeInference.h"
+
+namespace js {
+
+// Memory required for an unboxed value of a given type. Returns zero for types
+// which can't be used for unboxed objects.
+static inline size_t
+UnboxedTypeSize(JSValueType type)
+{
+    switch (type) {
+      case JSVAL_TYPE_BOOLEAN: return 1;
+      case JSVAL_TYPE_INT32:   return 4;
+      case JSVAL_TYPE_DOUBLE:  return 8;
+      case JSVAL_TYPE_STRING:  return sizeof(void*);
+      case JSVAL_TYPE_OBJECT:  return sizeof(void*);
+      default:                 return 0;
+    }
+}
+
+static inline bool
+UnboxedTypeNeedsPreBarrier(JSValueType type)
+{
+    return type == JSVAL_TYPE_STRING || type == JSVAL_TYPE_OBJECT;
+}
+
+static inline bool
+UnboxedTypeNeedsPostBarrier(JSValueType type)
+{
+    return type == JSVAL_TYPE_OBJECT;
+}
+
+// Class tracking information specific to unboxed objects.
+class UnboxedLayout : public mozilla::LinkedListElement<UnboxedLayout>
+{
+  public:
+    struct Property {
+        PropertyName* name;
+        uint32_t offset;
+        JSValueType type;
+
+        Property()
+          : name(nullptr), offset(UINT32_MAX), type(JSVAL_TYPE_MAGIC)
+        {}
+    };
+
+    typedef Vector<Property, 0, SystemAllocPolicy> PropertyVector;
+
+  private:
+    // If objects in this group have ever been converted to native objects,
+    // these store the corresponding native group and initial shape for such
+    // objects. Type information for this object is reflected in nativeGroup.
+    GCPtrObjectGroup nativeGroup_;
+    GCPtrShape nativeShape_;
+
+    // Any script/pc which the associated group is created for.
+    GCPtrScript allocationScript_;
+    jsbytecode* allocationPc_;
+
+    // If nativeGroup is set and this object originally had a TypeNewScript or
+    // was keyed to an allocation site, this points to the group which replaced
+    // this one. This link is only needed to keep the replacement group from
+    // being GC'ed. If it were GC'ed and a new one regenerated later, that new
+    // group might have a different allocation kind from this group.
+    GCPtrObjectGroup replacementGroup_;
+
+    // The following members are only used for unboxed plain objects.
+
+    // All properties on objects with this layout, in enumeration order.
+    PropertyVector properties_;
+
+    // Byte size of the data for objects with this layout.
+    size_t size_;
+
+    // Any 'new' script information associated with this layout.
+    TypeNewScript* newScript_;
+
+    // List for use in tracing objects with this layout. This has the same
+    // structure as the trace list on a TypeDescr.
+    int32_t* traceList_;
+
+    // If this layout has been used to construct script or JSON constant
+    // objects, this code might be filled in to more quickly fill in objects
+    // from an array of values.
+    GCPtrJitCode constructorCode_;
+
+  public:
+    UnboxedLayout()
+      : nativeGroup_(nullptr), nativeShape_(nullptr),
+        allocationScript_(nullptr), allocationPc_(nullptr), replacementGroup_(nullptr),
+        size_(0), newScript_(nullptr), traceList_(nullptr), constructorCode_(nullptr)
+    {}
+
+    bool initProperties(const PropertyVector& properties, size_t size) {
+        size_ = size;
+        return properties_.appendAll(properties);
+    }
+
+    ~UnboxedLayout() {
+        if (newScript_)
+            newScript_->clear();
+        js_delete(newScript_);
+        js_free(traceList_);
+
+        nativeGroup_.init(nullptr);
+        nativeShape_.init(nullptr);
+        replacementGroup_.init(nullptr);
+        constructorCode_.init(nullptr);
+    }
+
+    void detachFromCompartment();
+
+    const PropertyVector& properties() const {
+        return properties_;
+    }
+
+    TypeNewScript* newScript() const {
+        return newScript_;
+    }
+
+    void setNewScript(TypeNewScript* newScript, bool writeBarrier = true);
+
+    JSScript* allocationScript() const {
+        return allocationScript_;
+    }
+
+    jsbytecode* allocationPc() const {
+        return allocationPc_;
+    }
+
+    void setAllocationSite(JSScript* script, jsbytecode* pc) {
+        allocationScript_ = script;
+        allocationPc_ = pc;
+    }
+
+    const int32_t* traceList() const {
+        return traceList_;
+    }
+
+    void setTraceList(int32_t* traceList) {
+        traceList_ = traceList;
+    }
+
+    const Property* lookup(JSAtom* atom) const {
+        for (size_t i = 0; i < properties_.length(); i++) {
+            if (properties_[i].name == atom)
+                return &properties_[i];
+        }
+        return nullptr;
+    }
+
+    const Property* lookup(jsid id) const {
+        if (JSID_IS_STRING(id))
+            return lookup(JSID_TO_ATOM(id));
+        return nullptr;
+    }
+
+    size_t size() const {
+        return size_;
+    }
+
+    ObjectGroup* nativeGroup() const {
+        return nativeGroup_;
+    }
+
+    Shape* nativeShape() const {
+        return nativeShape_;
+    }
+
+    jit::JitCode* constructorCode() const {
+        return constructorCode_;
+    }
+
+    void setConstructorCode(jit::JitCode* code) {
+        constructorCode_ = code;
+    }
+
+    inline gc::AllocKind getAllocKind() const;
+
+    void trace(JSTracer* trc);
+
+    size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf);
+
+    static bool makeNativeGroup(JSContext* cx, ObjectGroup* group);
+    static bool makeConstructorCode(JSContext* cx, HandleObjectGroup group);
+};
+
+// Class for expando objects holding extra properties given to an unboxed plain
+// object. These objects behave identically to normal native plain objects, and
+// have a separate Class to distinguish them for memory usage reporting.
+class UnboxedExpandoObject : public NativeObject
+{
+  public:
+    static const Class class_;
+};
+
+// Class for a plain object using an unboxed representation. The physical
+// layout of these objects is identical to that of an InlineTypedObject, though
+// these objects use an UnboxedLayout instead of a TypeDescr to keep track of
+// how their properties are stored.
+class UnboxedPlainObject : public JSObject
+{
+    // Optional object which stores extra properties on this object. This is
+    // not automatically barriered to avoid problems if the object is converted
+    // to a native. See ensureExpando().
+    UnboxedExpandoObject* expando_;
+
+    // Start of the inline data, which immediately follows the group and extra properties.
+    uint8_t data_[1];
+
+  public:
+    static const Class class_;
+
+    static bool obj_lookupProperty(JSContext* cx, HandleObject obj,
+                                   HandleId id, MutableHandleObject objp,
+                                   MutableHandleShape propp);
+
+    static bool obj_defineProperty(JSContext* cx, HandleObject obj, HandleId id,
+                                   Handle<PropertyDescriptor> desc,
+                                   ObjectOpResult& result);
+
+    static bool obj_hasProperty(JSContext* cx, HandleObject obj, HandleId id, bool* foundp);
+
+    static bool obj_getProperty(JSContext* cx, HandleObject obj, HandleValue receiver,
+                                HandleId id, MutableHandleValue vp);
+
+    static bool obj_setProperty(JSContext* cx, HandleObject obj, HandleId id, HandleValue v,
+                                HandleValue receiver, ObjectOpResult& result);
+
+    static bool obj_getOwnPropertyDescriptor(JSContext* cx, HandleObject obj, HandleId id,
+                                             MutableHandle<PropertyDescriptor> desc);
+
+    static bool obj_deleteProperty(JSContext* cx, HandleObject obj, HandleId id,
+                                   ObjectOpResult& result);
+
+    static bool obj_enumerate(JSContext* cx, HandleObject obj, AutoIdVector& properties,
+                              bool enumerableOnly);
+    static bool obj_watch(JSContext* cx, HandleObject obj, HandleId id, HandleObject callable);
+
+    inline const UnboxedLayout& layout() const;
+
+    const UnboxedLayout& layoutDontCheckGeneration() const {
+        return group()->unboxedLayoutDontCheckGeneration();
+    }
+
+    uint8_t* data() {
+        return &data_[0];
+    }
+
+    UnboxedExpandoObject* maybeExpando() const {
+        return expando_;
+    }
+
+    void initExpando() {
+        expando_ = nullptr;
+    }
+
+    // For use during GC.
+    JSObject** addressOfExpando() {
+        return reinterpret_cast<JSObject**>(&expando_);
+    }
+
+    bool containsUnboxedOrExpandoProperty(ExclusiveContext* cx, jsid id) const;
+
+    static UnboxedExpandoObject* ensureExpando(JSContext* cx, Handle<UnboxedPlainObject*> obj);
+
+    bool setValue(ExclusiveContext* cx, const UnboxedLayout::Property& property, const Value& v);
+    Value getValue(const UnboxedLayout::Property& property, bool maybeUninitialized = false);
+
+    static bool convertToNative(JSContext* cx, JSObject* obj);
+    static UnboxedPlainObject* create(ExclusiveContext* cx, HandleObjectGroup group,
+                                      NewObjectKind newKind);
+    static JSObject* createWithProperties(ExclusiveContext* cx, HandleObjectGroup group,
+                                          NewObjectKind newKind, IdValuePair* properties);
+
+    void fillAfterConvert(ExclusiveContext* cx,
+                          Handle<GCVector<Value>> values, size_t* valueCursor);
+
+    static void trace(JSTracer* trc, JSObject* object);
+
+    static size_t offsetOfExpando() {
+        return offsetof(UnboxedPlainObject, expando_);
+    }
+
+    static size_t offsetOfData() {
+        return offsetof(UnboxedPlainObject, data_[0]);
+    }
+};
+
+inline gc::AllocKind
+UnboxedLayout::getAllocKind() const
+{
+    MOZ_ASSERT(size());
+    return gc::GetGCObjectKindForBytes(UnboxedPlainObject::offsetOfData() + size());
+}
+
+} // namespace js
+
+namespace JS {
+
+template <>
+struct DeletePolicy<js::UnboxedLayout> : public js::GCManagedDeletePolicy<js::UnboxedLayout>
+{};
+
+} /* namespace JS */
+
+#endif /* vm_UnboxedObject_h */