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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /js/src/vm/UnboxedObject.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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+/* -*- 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_;
+
+ // The following members are only used for unboxed arrays.
+
+ // The type of array elements.
+ JSValueType elementType_;
+
+ public:
+ UnboxedLayout()
+ : nativeGroup_(nullptr), nativeShape_(nullptr),
+ allocationScript_(nullptr), allocationPc_(nullptr), replacementGroup_(nullptr),
+ size_(0), newScript_(nullptr), traceList_(nullptr), constructorCode_(nullptr),
+ elementType_(JSVAL_TYPE_MAGIC)
+ {}
+
+ bool initProperties(const PropertyVector& properties, size_t size) {
+ size_ = size;
+ return properties_.appendAll(properties);
+ }
+
+ void initArray(JSValueType elementType) {
+ elementType_ = elementType;
+ }
+
+ ~UnboxedLayout() {
+ if (newScript_)
+ newScript_->clear();
+ js_delete(newScript_);
+ js_free(traceList_);
+
+ nativeGroup_.init(nullptr);
+ nativeShape_.init(nullptr);
+ replacementGroup_.init(nullptr);
+ constructorCode_.init(nullptr);
+ }
+
+ bool isArray() const {
+ return elementType_ != JSVAL_TYPE_MAGIC;
+ }
+
+ 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;
+ }
+
+ JSValueType elementType() const {
+ return elementType_;
+ }
+
+ 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]);
+ }
+};
+
+// Try to construct an UnboxedLayout for each of the preliminary objects,
+// provided they all match the template shape. If successful, converts the
+// preliminary objects and their group to the new unboxed representation.
+bool
+TryConvertToUnboxedLayout(ExclusiveContext* cx, AutoEnterAnalysis& enter, Shape* templateShape,
+ ObjectGroup* group, PreliminaryObjectArray* objects);
+
+inline gc::AllocKind
+UnboxedLayout::getAllocKind() const
+{
+ MOZ_ASSERT(size());
+ return gc::GetGCObjectKindForBytes(UnboxedPlainObject::offsetOfData() + size());
+}
+
+// Class for an array object using an unboxed representation.
+class UnboxedArrayObject : public JSObject
+{
+ // Elements pointer for the object.
+ uint8_t* elements_;
+
+ // The nominal array length. This always fits in an int32_t.
+ uint32_t length_;
+
+ // Value indicating the allocated capacity and initialized length of the
+ // array. The top CapacityBits bits are an index into CapacityArray, which
+ // indicates the elements capacity. The low InitializedLengthBits store the
+ // initialized length of the array.
+ uint32_t capacityIndexAndInitializedLength_;
+
+ // If the elements are inline, they will point here.
+ uint8_t inlineElements_[1];
+
+ public:
+ static const uint32_t CapacityBits = 6;
+ static const uint32_t CapacityShift = 26;
+
+ static const uint32_t CapacityMask = uint32_t(-1) << CapacityShift;
+ static const uint32_t InitializedLengthMask = (1 << CapacityShift) - 1;
+
+ static const uint32_t MaximumCapacity = InitializedLengthMask;
+ static const uint32_t MinimumDynamicCapacity = 8;
+
+ static const uint32_t CapacityArray[];
+
+ // Capacity index which indicates the array's length is also its capacity.
+ static const uint32_t CapacityMatchesLengthIndex = 0;
+
+ private:
+ static inline uint32_t computeCapacity(uint32_t index, uint32_t length) {
+ if (index == CapacityMatchesLengthIndex)
+ return length;
+ return CapacityArray[index];
+ }
+
+ static uint32_t chooseCapacityIndex(uint32_t capacity, uint32_t length);
+ static uint32_t exactCapacityIndex(uint32_t capacity);
+
+ 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();
+ }
+
+ JSValueType elementType() const {
+ return layoutDontCheckGeneration().elementType();
+ }
+
+ uint32_t elementSize() const {
+ return UnboxedTypeSize(elementType());
+ }
+
+ static bool convertToNative(JSContext* cx, JSObject* obj);
+ static UnboxedArrayObject* create(ExclusiveContext* cx, HandleObjectGroup group,
+ uint32_t length, NewObjectKind newKind,
+ uint32_t maxLength = MaximumCapacity);
+
+ static bool convertToNativeWithGroup(ExclusiveContext* cx, JSObject* obj,
+ ObjectGroup* group, Shape* shape);
+ bool convertInt32ToDouble(ExclusiveContext* cx, ObjectGroup* group);
+
+ void fillAfterConvert(ExclusiveContext* cx,
+ Handle<GCVector<Value>> values, size_t* valueCursor);
+
+ static void trace(JSTracer* trc, JSObject* object);
+ static void objectMoved(JSObject* obj, const JSObject* old);
+ static void finalize(FreeOp* fop, JSObject* obj);
+
+ static size_t objectMovedDuringMinorGC(JSTracer* trc, JSObject* dst, JSObject* src,
+ gc::AllocKind allocKind);
+
+ uint8_t* elements() {
+ return elements_;
+ }
+
+ bool hasInlineElements() const {
+ return elements_ == &inlineElements_[0];
+ }
+
+ uint32_t length() const {
+ return length_;
+ }
+
+ uint32_t initializedLength() const {
+ return capacityIndexAndInitializedLength_ & InitializedLengthMask;
+ }
+
+ uint32_t capacityIndex() const {
+ return (capacityIndexAndInitializedLength_ & CapacityMask) >> CapacityShift;
+ }
+
+ uint32_t capacity() const {
+ return computeCapacity(capacityIndex(), length());
+ }
+
+ bool containsProperty(ExclusiveContext* cx, jsid id);
+
+ bool setElement(ExclusiveContext* cx, size_t index, const Value& v);
+ bool initElement(ExclusiveContext* cx, size_t index, const Value& v);
+ void initElementNoTypeChange(size_t index, const Value& v);
+ Value getElement(size_t index);
+
+ template <JSValueType Type> inline bool setElementSpecific(ExclusiveContext* cx, size_t index,
+ const Value& v);
+ template <JSValueType Type> inline void setElementNoTypeChangeSpecific(size_t index, const Value& v);
+ template <JSValueType Type> inline bool initElementSpecific(ExclusiveContext* cx, size_t index,
+ const Value& v);
+ template <JSValueType Type> inline void initElementNoTypeChangeSpecific(size_t index, const Value& v);
+ template <JSValueType Type> inline Value getElementSpecific(size_t index);
+ template <JSValueType Type> inline void triggerPreBarrier(size_t index);
+
+ bool growElements(ExclusiveContext* cx, size_t cap);
+ void shrinkElements(ExclusiveContext* cx, size_t cap);
+
+ static uint32_t offsetOfElements() {
+ return offsetof(UnboxedArrayObject, elements_);
+ }
+ static uint32_t offsetOfLength() {
+ return offsetof(UnboxedArrayObject, length_);
+ }
+ static uint32_t offsetOfCapacityIndexAndInitializedLength() {
+ return offsetof(UnboxedArrayObject, capacityIndexAndInitializedLength_);
+ }
+ static uint32_t offsetOfInlineElements() {
+ return offsetof(UnboxedArrayObject, inlineElements_);
+ }
+
+ void setLengthInt32(uint32_t length) {
+ MOZ_ASSERT(length <= INT32_MAX);
+ length_ = length;
+ }
+
+ inline void setLength(ExclusiveContext* cx, uint32_t len);
+ inline void setInitializedLength(uint32_t initlen);
+
+ inline void setInitializedLengthNoBarrier(uint32_t initlen) {
+ MOZ_ASSERT(initlen <= InitializedLengthMask);
+ capacityIndexAndInitializedLength_ =
+ (capacityIndexAndInitializedLength_ & CapacityMask) | initlen;
+ }
+
+ private:
+ void setInlineElements() {
+ elements_ = &inlineElements_[0];
+ }
+
+ void setCapacityIndex(uint32_t index) {
+ MOZ_ASSERT(index <= (CapacityMask >> CapacityShift));
+ capacityIndexAndInitializedLength_ =
+ (index << CapacityShift) | initializedLength();
+ }
+};
+
+} // namespace js
+
+namespace JS {
+
+template <>
+struct DeletePolicy<js::UnboxedLayout> : public js::GCManagedDeletePolicy<js::UnboxedLayout>
+{};
+
+} /* namespace JS */
+
+#endif /* vm_UnboxedObject_h */