Remove Unboxed Object code from jit, Part 4.

7 files changed, 20 insertions, 406 deletions

diff --git a/js/src/jit/BaselineIC.cpp b/js/src/jit/BaselineIC.cpp
index 56049a2a07..d95d08edcd 100644
--- a/js/src/jit/BaselineIC.cpp
+++ b/js/src/jit/BaselineIC.cpp
@@ -1148,56 +1148,6 @@ TryAttachNativeOrUnboxedGetValueElemStub(JSContext* cx, HandleScript script, jsb
 
     ICStub* monitorStub = stub->fallbackMonitorStub()->firstMonitorStub();
 
-    if (obj->is<UnboxedPlainObject>() && holder == obj) {
-        const UnboxedLayout::Property* property = obj->as<UnboxedPlainObject>().layout().lookup(id);
-
-        // Once unboxed objects support symbol-keys, we need to change the following accordingly
-        MOZ_ASSERT_IF(!keyVal.isString(), !property);
-
-        if (property) {
-            if (!cx->runtime()->jitSupportsFloatingPoint)
-                return true;
-
-            RootedPropertyName name(cx, JSID_TO_ATOM(id)->asPropertyName());
-            ICGetElemNativeCompiler<PropertyName*> compiler(cx, ICStub::GetElem_UnboxedPropertyName,
-                                                            monitorStub, obj, holder,
-                                                            name,
-                                                            ICGetElemNativeStub::UnboxedProperty,
-                                                            needsAtomize, property->offset +
-                                                            UnboxedPlainObject::offsetOfData(),
-                                                            property->type);
-            ICStub* newStub = compiler.getStub(compiler.getStubSpace(script));
-            if (!newStub)
-                return false;
-
-            stub->addNewStub(newStub);
-            *attached = true;
-            return true;
-        }
-
-        Shape* shape = obj->as<UnboxedPlainObject>().maybeExpando()->lookup(cx, id);
-        if (!shape->hasDefaultGetter() || !shape->hasSlot())
-            return true;
-
-        bool isFixedSlot;
-        uint32_t offset;
-        GetFixedOrDynamicSlotOffset(shape, &isFixedSlot, &offset);
-
-        ICGetElemNativeStub::AccessType acctype =
-            isFixedSlot ? ICGetElemNativeStub::FixedSlot
-                        : ICGetElemNativeStub::DynamicSlot;
-        ICGetElemNativeCompiler<T> compiler(cx, getGetElemStubKind<T>(ICStub::GetElem_NativeSlotName),
-                                            monitorStub, obj, holder, key,
-                                            acctype, needsAtomize, offset);
-        ICStub* newStub = compiler.getStub(compiler.getStubSpace(script));
-        if (!newStub)
-            return false;
-
-        stub->addNewStub(newStub);
-        *attached = true;
-        return true;
-    }
-
     if (!holder->isNative())
         return true;
 
@@ -1445,7 +1395,7 @@ TryAttachGetElemStub(JSContext* cx, JSScript* script, jsbytecode* pc, ICGetElem_
     }
 
     // Check for NativeObject[id] and UnboxedPlainObject[id] shape-optimizable accesses.
-    if (obj->isNative() || obj->is<UnboxedPlainObject>()) {
+    if (obj->isNative()) {
         RootedScript rootedScript(cx, script);
         if (rhs.isString()) {
             if (!TryAttachNativeOrUnboxedGetValueElemStub<PropertyName*>(cx, rootedScript, pc, stub,
@@ -1857,14 +1807,6 @@ ICGetElemNativeCompiler<T>::generateStubCode(MacroAssembler& masm)
     Register holderReg;
     if (obj_ == holder_) {
         holderReg = objReg;
-
-        if (obj_->is<UnboxedPlainObject>() && acctype_ != ICGetElemNativeStub::UnboxedProperty) {
-            // The property will be loaded off the unboxed expando.
-            masm.push(R1.scratchReg());
-            popR1 = true;
-            holderReg = R1.scratchReg();
-            masm.loadPtr(Address(objReg, UnboxedPlainObject::offsetOfExpando()), holderReg);
-        }
     } else {
         // Shape guard holder.
         if (regs.empty()) {
@@ -4494,20 +4436,7 @@ GuardGroupAndShapeMaybeUnboxedExpando(MacroAssembler& masm, JSObject* obj,
 
     // Guard against shape or expando shape.
     masm.loadPtr(Address(ICStubReg, offsetOfShape), scratch);
-    if (obj->is<UnboxedPlainObject>()) {
-        Address expandoAddress(object, UnboxedPlainObject::offsetOfExpando());
-        masm.branchPtr(Assembler::Equal, expandoAddress, ImmWord(0), failure);
-        Label done;
-        masm.push(object);
-        masm.loadPtr(expandoAddress, object);
-        masm.branchTestObjShape(Assembler::Equal, object, scratch, &done);
-        masm.pop(object);
-        masm.jump(failure);
-        masm.bind(&done);
-        masm.pop(object);
-    } else {
-        masm.branchTestObjShape(Assembler::NotEqual, object, scratch, failure);
-    }
+    masm.branchTestObjShape(Assembler::NotEqual, object, scratch, failure);
 }
 
 bool
@@ -4546,13 +4475,7 @@ ICSetProp_Native::Compiler::generateStubCode(MacroAssembler& masm)
     regs.takeUnchecked(objReg);
 
     Register holderReg;
-    if (obj_->is<UnboxedPlainObject>()) {
-        // We are loading off the expando object, so use that for the holder.
-        holderReg = regs.takeAny();
-        masm.loadPtr(Address(objReg, UnboxedPlainObject::offsetOfExpando()), holderReg);
-        if (!isFixedSlot_)
-            masm.loadPtr(Address(holderReg, NativeObject::offsetOfSlots()), holderReg);
-    } else if (isFixedSlot_) {
+    if (isFixedSlot_) {
         holderReg = objReg;
     } else {
         holderReg = regs.takeAny();
@@ -4689,31 +4612,17 @@ ICSetPropNativeAddCompiler::generateStubCode(MacroAssembler& masm)
     regs.add(R0);
     regs.takeUnchecked(objReg);
 
-    if (obj_->is<UnboxedPlainObject>()) {
-        holderReg = regs.takeAny();
-        masm.loadPtr(Address(objReg, UnboxedPlainObject::offsetOfExpando()), holderReg);
-
-        // Write the expando object's new shape.
-        Address shapeAddr(holderReg, ShapedObject::offsetOfShape());
-        EmitPreBarrier(masm, shapeAddr, MIRType::Shape);
-        masm.loadPtr(Address(ICStubReg, ICSetProp_NativeAdd::offsetOfNewShape()), scratch);
-        masm.storePtr(scratch, shapeAddr);
+    // Write the object's new shape.
+    Address shapeAddr(objReg, ShapedObject::offsetOfShape());
+    EmitPreBarrier(masm, shapeAddr, MIRType::Shape);
+    masm.loadPtr(Address(ICStubReg, ICSetProp_NativeAdd::offsetOfNewShape()), scratch);
+    masm.storePtr(scratch, shapeAddr);
 
-        if (!isFixedSlot_)
-            masm.loadPtr(Address(holderReg, NativeObject::offsetOfSlots()), holderReg);
+    if (isFixedSlot_) {
+        holderReg = objReg;
     } else {
-        // Write the object's new shape.
-        Address shapeAddr(objReg, ShapedObject::offsetOfShape());
-        EmitPreBarrier(masm, shapeAddr, MIRType::Shape);
-        masm.loadPtr(Address(ICStubReg, ICSetProp_NativeAdd::offsetOfNewShape()), scratch);
-        masm.storePtr(scratch, shapeAddr);
-
-        if (isFixedSlot_) {
-            holderReg = objReg;
-        } else {
-            holderReg = regs.takeAny();
-            masm.loadPtr(Address(objReg, NativeObject::offsetOfSlots()), holderReg);
-        }
+        holderReg = regs.takeAny();
+        masm.loadPtr(Address(objReg, NativeObject::offsetOfSlots()), holderReg);
     }
 
     // Perform the store.  No write barrier required since this is a new
diff --git a/js/src/jit/CodeGenerator.cpp b/js/src/jit/CodeGenerator.cpp
index 71a8890f34..a276ab9afc 100644
--- a/js/src/jit/CodeGenerator.cpp
+++ b/js/src/jit/CodeGenerator.cpp
@@ -8383,11 +8383,6 @@ CodeGenerator::visitStoreUnboxedPointer(LStoreUnboxedPointer* lir)
     }
 }
 
-typedef bool (*ConvertUnboxedObjectToNativeFn)(JSContext*, JSObject*);
-static const VMFunction ConvertUnboxedPlainObjectToNativeInfo =
-    FunctionInfo<ConvertUnboxedObjectToNativeFn>(UnboxedPlainObject::convertToNative,
-                                                 "UnboxedPlainObject::convertToNative");
-
 typedef bool (*ArrayPopShiftFn)(JSContext*, HandleObject, MutableHandleValue);
 static const VMFunction ArrayPopDenseInfo =
     FunctionInfo<ArrayPopShiftFn>(jit::ArrayPopDense, "ArrayPopDense");
@@ -8680,11 +8675,11 @@ CodeGenerator::visitIteratorStartO(LIteratorStartO* lir)
     masm.loadPtr(Address(niTemp, offsetof(NativeIterator, guard_array)), temp2);
 
     // Compare object with the first receiver guard. The last iterator can only
-    // match for native objects and unboxed objects.
+    // match for native objects.
     {
         Address groupAddr(temp2, offsetof(ReceiverGuard, group));
         Address shapeAddr(temp2, offsetof(ReceiverGuard, shape));
-        Label guardDone, shapeMismatch, noExpando;
+        Label guardDone, shapeMismatch;
         masm.loadObjShape(obj, temp1);
         masm.branchPtr(Assembler::NotEqual, shapeAddr, temp1, &shapeMismatch);
 
@@ -8696,12 +8691,6 @@ CodeGenerator::visitIteratorStartO(LIteratorStartO* lir)
         masm.bind(&shapeMismatch);
         masm.loadObjGroup(obj, temp1);
         masm.branchPtr(Assembler::NotEqual, groupAddr, temp1, ool->entry());
-        masm.loadPtr(Address(obj, UnboxedPlainObject::offsetOfExpando()), temp1);
-        masm.branchTestPtr(Assembler::Zero, temp1, temp1, &noExpando);
-        branchIfNotEmptyObjectElements(temp1, ool->entry());
-        masm.loadObjShape(temp1, temp1);
-        masm.bind(&noExpando);
-        masm.branchPtr(Assembler::NotEqual, shapeAddr, temp1, ool->entry());
         masm.bind(&guardDone);
     }
 
diff --git a/js/src/jit/IonBuilder.cpp b/js/src/jit/IonBuilder.cpp
index fc864a1976..a54a58add6 100644
--- a/js/src/jit/IonBuilder.cpp
+++ b/js/src/jit/IonBuilder.cpp
@@ -10925,63 +10925,6 @@ IonBuilder::getDefiniteSlot(TemporaryTypeSet* types, PropertyName* name, uint32_
     return slot;
 }
 
-uint32_t
-IonBuilder::getUnboxedOffset(TemporaryTypeSet* types, PropertyName* name, JSValueType* punboxedType)
-{
-    if (!types || types->unknownObject() || !types->objectOrSentinel()) {
-        trackOptimizationOutcome(TrackedOutcome::NoTypeInfo);
-        return UINT32_MAX;
-    }
-
-    uint32_t offset = UINT32_MAX;
-
-    for (size_t i = 0; i < types->getObjectCount(); i++) {
-        TypeSet::ObjectKey* key = types->getObject(i);
-        if (!key)
-            continue;
-
-        if (key->unknownProperties()) {
-            trackOptimizationOutcome(TrackedOutcome::UnknownProperties);
-            return UINT32_MAX;
-        }
-
-        if (key->isSingleton()) {
-            trackOptimizationOutcome(TrackedOutcome::Singleton);
-            return UINT32_MAX;
-        }
-
-        UnboxedLayout* layout = key->group()->maybeUnboxedLayout();
-        if (!layout) {
-            trackOptimizationOutcome(TrackedOutcome::NotUnboxed);
-            return UINT32_MAX;
-        }
-
-        const UnboxedLayout::Property* property = layout->lookup(name);
-        if (!property) {
-            trackOptimizationOutcome(TrackedOutcome::StructNoField);
-            return UINT32_MAX;
-        }
-
-        if (layout->nativeGroup()) {
-            trackOptimizationOutcome(TrackedOutcome::UnboxedConvertedToNative);
-            return UINT32_MAX;
-        }
-
-        if (offset == UINT32_MAX) {
-            offset = property->offset;
-            *punboxedType = property->type;
-        } else if (offset != property->offset) {
-            trackOptimizationOutcome(TrackedOutcome::InconsistentFieldOffset);
-            return UINT32_MAX;
-        } else if (*punboxedType != property->type) {
-            trackOptimizationOutcome(TrackedOutcome::InconsistentFieldType);
-            return UINT32_MAX;
-        }
-    }
-
-    return offset;
-}
-
 bool
 IonBuilder::jsop_runonce()
 {
@@ -11948,72 +11891,6 @@ IonBuilder::getPropTryModuleNamespace(bool* emitted, MDefinition* obj, PropertyN
     return true;
 }
 
-MInstruction*
-IonBuilder::loadUnboxedProperty(MDefinition* obj, size_t offset, JSValueType unboxedType,
-                                BarrierKind barrier, TemporaryTypeSet* types)
-{
-    // loadUnboxedValue is designed to load any value as if it were contained in
-    // an array. Thus a property offset is converted to an index, when the
-    // object is reinterpreted as an array of properties of the same size.
-    size_t index = offset / UnboxedTypeSize(unboxedType);
-    MInstruction* indexConstant = MConstant::New(alloc(), Int32Value(index));
-    current->add(indexConstant);
-
-    return loadUnboxedValue(obj, UnboxedPlainObject::offsetOfData(),
-                            indexConstant, unboxedType, barrier, types);
-}
-
-MInstruction*
-IonBuilder::loadUnboxedValue(MDefinition* elements, size_t elementsOffset,
-                             MDefinition* index, JSValueType unboxedType,
-                             BarrierKind barrier, TemporaryTypeSet* types)
-{
-    MInstruction* load;
-    switch (unboxedType) {
-      case JSVAL_TYPE_BOOLEAN:
-        load = MLoadUnboxedScalar::New(alloc(), elements, index, Scalar::Uint8,
-                                       DoesNotRequireMemoryBarrier, elementsOffset);
-        load->setResultType(MIRType::Boolean);
-        break;
-
-      case JSVAL_TYPE_INT32:
-        load = MLoadUnboxedScalar::New(alloc(), elements, index, Scalar::Int32,
-                                       DoesNotRequireMemoryBarrier, elementsOffset);
-        load->setResultType(MIRType::Int32);
-        break;
-
-      case JSVAL_TYPE_DOUBLE:
-        load = MLoadUnboxedScalar::New(alloc(), elements, index, Scalar::Float64,
-                                       DoesNotRequireMemoryBarrier, elementsOffset,
-                                       /* canonicalizeDoubles = */ false);
-        load->setResultType(MIRType::Double);
-        break;
-
-      case JSVAL_TYPE_STRING:
-        load = MLoadUnboxedString::New(alloc(), elements, index, elementsOffset);
-        break;
-
-      case JSVAL_TYPE_OBJECT: {
-        MLoadUnboxedObjectOrNull::NullBehavior nullBehavior;
-        if (types->hasType(TypeSet::NullType()))
-            nullBehavior = MLoadUnboxedObjectOrNull::HandleNull;
-        else if (barrier != BarrierKind::NoBarrier)
-            nullBehavior = MLoadUnboxedObjectOrNull::BailOnNull;
-        else
-            nullBehavior = MLoadUnboxedObjectOrNull::NullNotPossible;
-        load = MLoadUnboxedObjectOrNull::New(alloc(), elements, index, nullBehavior,
-                                             elementsOffset);
-        break;
-      }
-
-      default:
-        MOZ_CRASH();
-    }
-
-    current->add(load);
-    return load;
-}
-
 MDefinition*
 IonBuilder::addShapeGuardsForGetterSetter(MDefinition* obj, JSObject* holder, Shape* holderShape,
                 const BaselineInspector::ReceiverVector& receivers,
@@ -12835,66 +12712,6 @@ IonBuilder::setPropTryDefiniteSlot(bool* emitted, MDefinition* obj,
     return true;
 }
 
-MInstruction*
-IonBuilder::storeUnboxedProperty(MDefinition* obj, size_t offset, JSValueType unboxedType,
-                                 MDefinition* value)
-{
-    size_t scaledOffsetConstant = offset / UnboxedTypeSize(unboxedType);
-    MInstruction* scaledOffset = MConstant::New(alloc(), Int32Value(scaledOffsetConstant));
-    current->add(scaledOffset);
-
-    return storeUnboxedValue(obj, obj, UnboxedPlainObject::offsetOfData(),
-                             scaledOffset, unboxedType, value);
-}
-
-MInstruction*
-IonBuilder::storeUnboxedValue(MDefinition* obj, MDefinition* elements, int32_t elementsOffset,
-                              MDefinition* scaledOffset, JSValueType unboxedType,
-                              MDefinition* value, bool preBarrier /* = true */)
-{
-    MInstruction* store;
-    switch (unboxedType) {
-      case JSVAL_TYPE_BOOLEAN:
-        store = MStoreUnboxedScalar::New(alloc(), elements, scaledOffset, value, Scalar::Uint8,
-                                         MStoreUnboxedScalar::DontTruncateInput,
-                                         DoesNotRequireMemoryBarrier, elementsOffset);
-        break;
-
-      case JSVAL_TYPE_INT32:
-        store = MStoreUnboxedScalar::New(alloc(), elements, scaledOffset, value, Scalar::Int32,
-                                         MStoreUnboxedScalar::DontTruncateInput,
-                                         DoesNotRequireMemoryBarrier, elementsOffset);
-        break;
-
-      case JSVAL_TYPE_DOUBLE:
-        store = MStoreUnboxedScalar::New(alloc(), elements, scaledOffset, value, Scalar::Float64,
-                                         MStoreUnboxedScalar::DontTruncateInput,
-                                         DoesNotRequireMemoryBarrier, elementsOffset);
-        break;
-
-      case JSVAL_TYPE_STRING:
-        store = MStoreUnboxedString::New(alloc(), elements, scaledOffset, value,
-                                         elementsOffset, preBarrier);
-        break;
-
-      case JSVAL_TYPE_OBJECT:
-        MOZ_ASSERT(value->type() == MIRType::Object ||
-                   value->type() == MIRType::Null ||
-                   value->type() == MIRType::Value);
-        MOZ_ASSERT(!value->mightBeType(MIRType::Undefined),
-                   "MToObjectOrNull slow path is invalid for unboxed objects");
-        store = MStoreUnboxedObjectOrNull::New(alloc(), elements, scaledOffset, value, obj,
-                                               elementsOffset, preBarrier);
-        break;
-
-      default:
-        MOZ_CRASH();
-    }
-
-    current->add(store);
-    return store;
-}
-
 bool
 IonBuilder::setPropTryInlineAccess(bool* emitted, MDefinition* obj,
                                    PropertyName* name, MDefinition* value,
diff --git a/js/src/jit/IonBuilder.h b/js/src/jit/IonBuilder.h
index 1b97c47430..dd40b4bd69 100644
--- a/js/src/jit/IonBuilder.h
+++ b/js/src/jit/IonBuilder.h
@@ -1048,19 +1048,6 @@ class IonBuilder
     ResultWithOOM<bool> testNotDefinedProperty(MDefinition* obj, jsid id);
 
     uint32_t getDefiniteSlot(TemporaryTypeSet* types, PropertyName* name, uint32_t* pnfixed);
-    uint32_t getUnboxedOffset(TemporaryTypeSet* types, PropertyName* name,
-                              JSValueType* punboxedType);
-    MInstruction* loadUnboxedProperty(MDefinition* obj, size_t offset, JSValueType unboxedType,
-                                      BarrierKind barrier, TemporaryTypeSet* types);
-    MInstruction* loadUnboxedValue(MDefinition* elements, size_t elementsOffset,
-                                   MDefinition* scaledOffset, JSValueType unboxedType,
-                                   BarrierKind barrier, TemporaryTypeSet* types);
-    MInstruction* storeUnboxedProperty(MDefinition* obj, size_t offset, JSValueType unboxedType,
-                                       MDefinition* value);
-    MInstruction* storeUnboxedValue(MDefinition* obj,
-                                    MDefinition* elements, int32_t elementsOffset,
-                                    MDefinition* scaledOffset, JSValueType unboxedType,
-                                    MDefinition* value, bool preBarrier = true);
     MOZ_MUST_USE bool checkPreliminaryGroups(MDefinition *obj);
     MOZ_MUST_USE bool freezePropTypeSets(TemporaryTypeSet* types,
                                          JSObject* foundProto, PropertyName* name);
diff --git a/js/src/jit/IonCaches.cpp b/js/src/jit/IonCaches.cpp
index 2cd9fa4be6..9901bdd07d 100644
--- a/js/src/jit/IonCaches.cpp
+++ b/js/src/jit/IonCaches.cpp
@@ -31,7 +31,6 @@
 #include "jit/shared/Lowering-shared-inl.h"
 #include "vm/Interpreter-inl.h"
 #include "vm/Shape-inl.h"
-#include "vm/UnboxedObject-inl.h"
 
 using namespace js;
 using namespace js::jit;
@@ -620,26 +619,7 @@ TestMatchingReceiver(MacroAssembler& masm, IonCache::StubAttacher& attacher,
                      Register object, JSObject* obj, Label* failure,
                      bool alwaysCheckGroup = false)
 {
-    if (obj->is<UnboxedPlainObject>()) {
-        MOZ_ASSERT(failure);
-
-        masm.branchTestObjGroup(Assembler::NotEqual, object, obj->group(), failure);
-        Address expandoAddress(object, UnboxedPlainObject::offsetOfExpando());
-        if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando()) {
-            masm.branchPtr(Assembler::Equal, expandoAddress, ImmWord(0), failure);
-            Label success;
-            masm.push(object);
-            masm.loadPtr(expandoAddress, object);
-            masm.branchTestObjShape(Assembler::Equal, object, expando->lastProperty(),
-                                    &success);
-            masm.pop(object);
-            masm.jump(failure);
-            masm.bind(&success);
-            masm.pop(object);
-        } else {
-            masm.branchPtr(Assembler::NotEqual, expandoAddress, ImmWord(0), failure);
-        }
-    } else if (obj->is<TypedObject>()) {
+    if (obj->is<TypedObject>()) {
         attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
                                        Address(object, JSObject::offsetOfGroup()),
                                        ImmGCPtr(obj->group()), failure);
@@ -756,7 +736,6 @@ GenerateReadSlot(JSContext* cx, IonScript* ion, MacroAssembler& masm,
     // jump directly. Otherwise, jump to the end of the stub, so there's a
     // common point to patch.
     bool multipleFailureJumps = (obj != holder)
-                             || obj->is<UnboxedPlainObject>()
                              || (checkTDZ && output.hasValue())
                              || (failures != nullptr && failures->used());
 
@@ -775,7 +754,6 @@ GenerateReadSlot(JSContext* cx, IonScript* ion, MacroAssembler& masm,
     Register scratchReg = Register::FromCode(0); // Quell compiler warning.
 
     if (obj != holder ||
-        obj->is<UnboxedPlainObject>() ||
         !holder->as<NativeObject>().isFixedSlot(shape->slot()))
     {
         if (output.hasValue()) {
@@ -836,10 +814,6 @@ GenerateReadSlot(JSContext* cx, IonScript* ion, MacroAssembler& masm,
 
             holderReg = InvalidReg;
         }
-    } else if (obj->is<UnboxedPlainObject>()) {
-        holder = obj->as<UnboxedPlainObject>().maybeExpando();
-        holderReg = scratchReg;
-        masm.loadPtr(Address(object, UnboxedPlainObject::offsetOfExpando()), holderReg);
     } else {
         holderReg = object;
     }
@@ -2220,12 +2194,6 @@ GenerateSetSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
 
     NativeObject::slotsSizeMustNotOverflow();
 
-    if (obj->is<UnboxedPlainObject>()) {
-        obj = obj->as<UnboxedPlainObject>().maybeExpando();
-        masm.loadPtr(Address(object, UnboxedPlainObject::offsetOfExpando()), tempReg);
-        object = tempReg;
-    }
-
     if (obj->as<NativeObject>().isFixedSlot(shape->slot())) {
         Address addr(object, NativeObject::getFixedSlotOffset(shape->slot()));
 
@@ -2863,23 +2831,13 @@ GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
     masm.branchTestObjGroup(Assembler::NotEqual, object, oldGroup, failures);
     if (obj->maybeShape()) {
         masm.branchTestObjShape(Assembler::NotEqual, object, oldShape, failures);
-    } else {
-        MOZ_ASSERT(obj->is<UnboxedPlainObject>());
-
-        Address expandoAddress(object, UnboxedPlainObject::offsetOfExpando());
-        masm.branchPtr(Assembler::Equal, expandoAddress, ImmWord(0), failures);
-
-        masm.loadPtr(expandoAddress, tempReg);
-        masm.branchTestObjShape(Assembler::NotEqual, tempReg, oldShape, failures);
     }
 
     Shape* newShape = obj->maybeShape();
-    if (!newShape)
-        newShape = obj->as<UnboxedPlainObject>().maybeExpando()->lastProperty();
 
     // Guard that the incoming value is in the type set for the property
     // if a type barrier is required.
-    if (checkTypeset)
+    if (newShape && checkTypeset)
         CheckTypeSetForWrite(masm, obj, newShape->propid(), tempReg, value, failures);
 
     // Guard shapes along prototype chain.
@@ -2900,9 +2858,7 @@ GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
     }
 
     // Call a stub to (re)allocate dynamic slots, if necessary.
-    uint32_t newNumDynamicSlots = obj->is<UnboxedPlainObject>()
-                                  ? obj->as<UnboxedPlainObject>().maybeExpando()->numDynamicSlots()
-                                  : obj->as<NativeObject>().numDynamicSlots();
+    uint32_t newNumDynamicSlots = obj->as<NativeObject>().numDynamicSlots();
     if (NativeObject::dynamicSlotsCount(oldShape) != newNumDynamicSlots) {
         AllocatableRegisterSet regs(RegisterSet::Volatile());
         LiveRegisterSet save(regs.asLiveSet());
@@ -2913,12 +2869,6 @@ GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
         Register temp1 = regs.takeAnyGeneral();
         Register temp2 = regs.takeAnyGeneral();
 
-        if (obj->is<UnboxedPlainObject>()) {
-            // Pass the expando object to the stub.
-            masm.Push(object);
-            masm.loadPtr(Address(object, UnboxedPlainObject::offsetOfExpando()), object);
-        }
-
         masm.setupUnalignedABICall(temp1);
         masm.loadJSContext(temp1);
         masm.passABIArg(temp1);
@@ -2935,27 +2885,16 @@ GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
         masm.jump(&allocDone);
 
         masm.bind(&allocFailed);
-        if (obj->is<UnboxedPlainObject>())
-            masm.Pop(object);
         masm.PopRegsInMask(save);
         masm.jump(failures);
 
         masm.bind(&allocDone);
         masm.setFramePushed(framePushedAfterCall);
-        if (obj->is<UnboxedPlainObject>())
-            masm.Pop(object);
         masm.PopRegsInMask(save);
     }
 
     bool popObject = false;
 
-    if (obj->is<UnboxedPlainObject>()) {
-        masm.push(object);
-        popObject = true;
-        obj = obj->as<UnboxedPlainObject>().maybeExpando();
-        masm.loadPtr(Address(object, UnboxedPlainObject::offsetOfExpando()), object);
-    }
-
     // Write the object or expando object's new shape.
     Address shapeAddr(object, ShapedObject::offsetOfShape());
     if (cx->zone()->needsIncrementalBarrier())
@@ -2963,8 +2902,6 @@ GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& att
     masm.storePtr(ImmGCPtr(newShape), shapeAddr);
 
     if (oldGroup != obj->group()) {
-        MOZ_ASSERT(!obj->is<UnboxedPlainObject>());
-
         // Changing object's group from a partially to fully initialized group,
         // per the acquired properties analysis. Only change the group if the
         // old group still has a newScript.
diff --git a/js/src/jit/Recover.cpp b/js/src/jit/Recover.cpp
index 3edc6de8bc..793b631df0 100644
--- a/js/src/jit/Recover.cpp
+++ b/js/src/jit/Recover.cpp
@@ -30,7 +30,6 @@
 
 #include "vm/Interpreter-inl.h"
 #include "vm/NativeObject-inl.h"
-#include "vm/UnboxedObject-inl.h"
 
 using namespace js;
 using namespace js::jit;
diff --git a/js/src/jit/SharedIC.cpp b/js/src/jit/SharedIC.cpp
index 3139574629..05a95824fb 100644
--- a/js/src/jit/SharedIC.cpp
+++ b/js/src/jit/SharedIC.cpp
@@ -2244,8 +2244,7 @@ IsCacheableProtoChain(JSObject* obj, JSObject* holder, bool isDOMProxy)
     if (!isDOMProxy && !obj->isNative()) {
         if (obj == holder)
             return false;
-        if (!obj->is<UnboxedPlainObject>() &&
-            !obj->is<TypedObject>())
+        if (!obj->is<TypedObject>())
         {
             return false;
         }
@@ -2573,9 +2572,6 @@ CheckHasNoSuchProperty(JSContext* cx, JSObject* obj, PropertyName* name,
         } else if (curObj != obj) {
             // Non-native objects are only handled as the original receiver.
             return false;
-        } else if (curObj->is<UnboxedPlainObject>()) {
-            if (curObj->as<UnboxedPlainObject>().containsUnboxedOrExpandoProperty(cx, NameToId(name)))
-                return false;
         } else if (curObj->is<TypedObject>()) {
             if (curObj->as<TypedObject>().typeDescr().hasProperty(cx->names(), NameToId(name)))
                 return false;
@@ -2840,34 +2836,15 @@ GuardReceiverObject(MacroAssembler& masm, ReceiverGuard guard,
 {
     Address groupAddress(ICStubReg, receiverGuardOffset + HeapReceiverGuard::offsetOfGroup());
     Address shapeAddress(ICStubReg, receiverGuardOffset + HeapReceiverGuard::offsetOfShape());
-    Address expandoAddress(object, UnboxedPlainObject::offsetOfExpando());
 
     if (guard.group) {
         masm.loadPtr(groupAddress, scratch);
         masm.branchTestObjGroup(Assembler::NotEqual, object, scratch, failure);
-
-        if (guard.group->clasp() == &UnboxedPlainObject::class_ && !guard.shape) {
-            // Guard the unboxed object has no expando object.
-            masm.branchPtr(Assembler::NotEqual, expandoAddress, ImmWord(0), failure);
-        }
     }
 
     if (guard.shape) {
         masm.loadPtr(shapeAddress, scratch);
-        if (guard.group && guard.group->clasp() == &UnboxedPlainObject::class_) {
-            // Guard the unboxed object has a matching expando object.
-            masm.branchPtr(Assembler::Equal, expandoAddress, ImmWord(0), failure);
-            Label done;
-            masm.push(object);
-            masm.loadPtr(expandoAddress, object);
-            masm.branchTestObjShape(Assembler::Equal, object, scratch, &done);
-            masm.pop(object);
-            masm.jump(failure);
-            masm.bind(&done);
-            masm.pop(object);
-        } else {
-            masm.branchTestObjShape(Assembler::NotEqual, object, scratch, failure);
-        }
+        masm.branchTestObjShape(Assembler::NotEqual, object, scratch, failure);
     }
 }
 
@@ -4251,8 +4228,7 @@ DoNewObject(JSContext* cx, void* payload, ICNewObject_Fallback* stub, MutableHan
                 return false;
 
             if (!stub->invalid() &&
-                (templateObject->is<UnboxedPlainObject>() ||
-                 !templateObject->as<PlainObject>().hasDynamicSlots()))
+                !templateObject->as<PlainObject>().hasDynamicSlots())
             {
                 JitCode* code = GenerateNewObjectWithTemplateCode(cx, templateObject);
                 if (!code)