Create the Goanna Runtime Environment

1 files changed, 5069 insertions, 0 deletions

diff --git a/js/src/jit/IonCaches.cpp b/js/src/jit/IonCaches.cpp
new file mode 100644
index 000000000..0a0c7ac22
--- /dev/null
+++ b/js/src/jit/IonCaches.cpp
@@ -0,0 +1,5069 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * 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/. */
+
+#include "jit/IonCaches.h"
+
+#include "mozilla/SizePrintfMacros.h"
+#include "mozilla/TemplateLib.h"
+
+#include "jstypes.h"
+
+#include "builtin/TypedObject.h"
+#include "jit/BaselineIC.h"
+#include "jit/Ion.h"
+#include "jit/JitcodeMap.h"
+#include "jit/JitSpewer.h"
+#include "jit/Linker.h"
+#include "jit/Lowering.h"
+#ifdef JS_ION_PERF
+# include "jit/PerfSpewer.h"
+#endif
+#include "jit/VMFunctions.h"
+#include "js/Proxy.h"
+#include "vm/Shape.h"
+#include "vm/Stack.h"
+
+#include "jit/JitFrames-inl.h"
+#include "jit/MacroAssembler-inl.h"
+#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;
+
+using mozilla::tl::FloorLog2;
+
+typedef Rooted<TypedArrayObject*> RootedTypedArrayObject;
+
+void
+CodeLocationJump::repoint(JitCode* code, MacroAssembler* masm)
+{
+    MOZ_ASSERT(state_ == Relative);
+    size_t new_off = (size_t)raw_;
+#ifdef JS_SMALL_BRANCH
+    size_t jumpTableEntryOffset = reinterpret_cast<size_t>(jumpTableEntry_);
+#endif
+    if (masm != nullptr) {
+#ifdef JS_CODEGEN_X64
+        MOZ_ASSERT((uint64_t)raw_ <= UINT32_MAX);
+#endif
+        new_off = (uintptr_t)raw_;
+#ifdef JS_SMALL_BRANCH
+        jumpTableEntryOffset = masm->actualIndex(jumpTableEntryOffset);
+#endif
+    }
+    raw_ = code->raw() + new_off;
+#ifdef JS_SMALL_BRANCH
+    jumpTableEntry_ = Assembler::PatchableJumpAddress(code, (size_t) jumpTableEntryOffset);
+#endif
+    setAbsolute();
+}
+
+void
+CodeLocationLabel::repoint(JitCode* code, MacroAssembler* masm)
+{
+     MOZ_ASSERT(state_ == Relative);
+     size_t new_off = (size_t)raw_;
+     if (masm != nullptr) {
+#ifdef JS_CODEGEN_X64
+        MOZ_ASSERT((uint64_t)raw_ <= UINT32_MAX);
+#endif
+        new_off = (uintptr_t)raw_;
+     }
+     MOZ_ASSERT(new_off < code->instructionsSize());
+
+     raw_ = code->raw() + new_off;
+     setAbsolute();
+}
+
+void
+CodeOffsetJump::fixup(MacroAssembler* masm)
+{
+#ifdef JS_SMALL_BRANCH
+     jumpTableIndex_ = masm->actualIndex(jumpTableIndex_);
+#endif
+}
+
+const char*
+IonCache::CacheName(IonCache::Kind kind)
+{
+    static const char * const names[] =
+    {
+#define NAME(x) #x,
+        IONCACHE_KIND_LIST(NAME)
+#undef NAME
+    };
+    return names[kind];
+}
+
+const size_t IonCache::MAX_STUBS = 16;
+
+// Helper class which encapsulates logic to attach a stub to an IC by hooking
+// up rejoins and next stub jumps.
+//
+// The simplest stubs have a single jump to the next stub and look like the
+// following:
+//
+//    branch guard NEXTSTUB
+//    ... IC-specific code ...
+//    jump REJOIN
+//
+// This corresponds to:
+//
+//    attacher.branchNextStub(masm, ...);
+//    ... emit IC-specific code ...
+//    attacher.jumpRejoin(masm);
+//
+// Whether the stub needs multiple next stub jumps look like:
+//
+//   branch guard FAILURES
+//   ... IC-specific code ...
+//   branch another-guard FAILURES
+//   ... IC-specific code ...
+//   jump REJOIN
+//   FAILURES:
+//   jump NEXTSTUB
+//
+// This corresponds to:
+//
+//   Label failures;
+//   masm.branchX(..., &failures);
+//   ... emit IC-specific code ...
+//   masm.branchY(..., failures);
+//   ... emit more IC-specific code ...
+//   attacher.jumpRejoin(masm);
+//   masm.bind(&failures);
+//   attacher.jumpNextStub(masm);
+//
+// A convenience function |branchNextStubOrLabel| is provided in the case that
+// the stub sometimes has multiple next stub jumps and sometimes a single
+// one. If a non-nullptr label is passed in, a |branchPtr| will be made to
+// that label instead of a |branchPtrWithPatch| to the next stub.
+class IonCache::StubAttacher
+{
+  protected:
+    bool hasNextStubOffset_ : 1;
+    bool hasStubCodePatchOffset_ : 1;
+
+    IonCache& cache_;
+
+    CodeLocationLabel rejoinLabel_;
+    CodeOffsetJump nextStubOffset_;
+    CodeOffsetJump rejoinOffset_;
+    CodeOffset stubCodePatchOffset_;
+
+  public:
+    explicit StubAttacher(IonCache& cache)
+      : hasNextStubOffset_(false),
+        hasStubCodePatchOffset_(false),
+        cache_(cache),
+        rejoinLabel_(cache.rejoinLabel_),
+        nextStubOffset_(),
+        rejoinOffset_(),
+        stubCodePatchOffset_()
+    { }
+
+    // Value used instead of the JitCode self-reference of generated
+    // stubs. This value is needed for marking calls made inside stubs. This
+    // value would be replaced by the attachStub function after the allocation
+    // of the JitCode. The self-reference is used to keep the stub path alive
+    // even if the IonScript is invalidated or if the IC is flushed.
+    static const void* const STUB_ADDR;
+
+    template <class T1, class T2>
+    void branchNextStub(MacroAssembler& masm, Assembler::Condition cond, T1 op1, T2 op2) {
+        MOZ_ASSERT(!hasNextStubOffset_);
+        RepatchLabel nextStub;
+        nextStubOffset_ = masm.branchPtrWithPatch(cond, op1, op2, &nextStub);
+        hasNextStubOffset_ = true;
+        masm.bind(&nextStub);
+    }
+
+    template <class T1, class T2>
+    void branchNextStubOrLabel(MacroAssembler& masm, Assembler::Condition cond, T1 op1, T2 op2,
+                               Label* label)
+    {
+        if (label != nullptr)
+            masm.branchPtr(cond, op1, op2, label);
+        else
+            branchNextStub(masm, cond, op1, op2);
+    }
+
+    void jumpRejoin(MacroAssembler& masm) {
+        RepatchLabel rejoin;
+        rejoinOffset_ = masm.jumpWithPatch(&rejoin);
+        masm.bind(&rejoin);
+    }
+
+    void jumpNextStub(MacroAssembler& masm) {
+        MOZ_ASSERT(!hasNextStubOffset_);
+        RepatchLabel nextStub;
+        nextStubOffset_ = masm.jumpWithPatch(&nextStub);
+        hasNextStubOffset_ = true;
+        masm.bind(&nextStub);
+    }
+
+    void pushStubCodePointer(MacroAssembler& masm) {
+        // Push the JitCode pointer for the stub we're generating.
+        // WARNING:
+        // WARNING: If JitCode ever becomes relocatable, the following code is incorrect.
+        // WARNING: Note that we're not marking the pointer being pushed as an ImmGCPtr.
+        // WARNING: This location will be patched with the pointer of the generated stub,
+        // WARNING: such as it can be marked when a call is made with this stub. Be aware
+        // WARNING: that ICs are not marked and so this stub will only be kept alive iff
+        // WARNING: it is on the stack at the time of the GC. No ImmGCPtr is needed as the
+        // WARNING: stubs are flushed on GC.
+        // WARNING:
+        MOZ_ASSERT(!hasStubCodePatchOffset_);
+        stubCodePatchOffset_ = masm.PushWithPatch(ImmPtr(STUB_ADDR));
+        hasStubCodePatchOffset_ = true;
+    }
+
+    void patchRejoinJump(MacroAssembler& masm, JitCode* code) {
+        rejoinOffset_.fixup(&masm);
+        CodeLocationJump rejoinJump(code, rejoinOffset_);
+        PatchJump(rejoinJump, rejoinLabel_);
+    }
+
+    void patchStubCodePointer(JitCode* code) {
+        if (hasStubCodePatchOffset_) {
+            Assembler::PatchDataWithValueCheck(CodeLocationLabel(code, stubCodePatchOffset_),
+                                               ImmPtr(code), ImmPtr(STUB_ADDR));
+        }
+    }
+
+    void patchNextStubJump(MacroAssembler& masm, JitCode* code) {
+        // If this path is not taken, we are producing an entry which can no
+        // longer go back into the update function.
+        if (hasNextStubOffset_) {
+            nextStubOffset_.fixup(&masm);
+            CodeLocationJump nextStubJump(code, nextStubOffset_);
+            PatchJump(nextStubJump, cache_.fallbackLabel_);
+
+            // When the last stub fails, it fallback to the ool call which can
+            // produce a stub. Next time we generate a stub, we will patch the
+            // nextStub jump to try the new stub.
+            cache_.lastJump_ = nextStubJump;
+        }
+    }
+};
+
+const void* const IonCache::StubAttacher::STUB_ADDR = (void*)0xdeadc0de;
+
+void
+IonCache::emitInitialJump(MacroAssembler& masm, RepatchLabel& entry)
+{
+    initialJump_ = masm.jumpWithPatch(&entry);
+    lastJump_ = initialJump_;
+    Label label;
+    masm.bind(&label);
+    rejoinLabel_ = CodeOffset(label.offset());
+}
+
+void
+IonCache::attachStub(MacroAssembler& masm, StubAttacher& attacher, CodeLocationJump lastJump,
+                     Handle<JitCode*> code)
+{
+    MOZ_ASSERT(canAttachStub());
+    incrementStubCount();
+
+    // Patch the previous nextStubJump of the last stub, or the jump from the
+    // codeGen, to jump into the newly allocated code.
+    PatchJump(lastJump, CodeLocationLabel(code), Reprotect);
+}
+
+IonCache::LinkStatus
+IonCache::linkCode(JSContext* cx, MacroAssembler& masm, StubAttacher& attacher, IonScript* ion,
+                   JitCode** code)
+{
+    Linker linker(masm);
+    *code = linker.newCode<CanGC>(cx, ION_CODE);
+    if (!*code)
+        return LINK_ERROR;
+
+    if (ion->invalidated())
+        return CACHE_FLUSHED;
+
+    // Update the success path to continue after the IC initial jump.
+    attacher.patchRejoinJump(masm, *code);
+
+    // Replace the STUB_ADDR constant by the address of the generated stub, such
+    // as it can be kept alive even if the cache is flushed (see
+    // MarkJitExitFrame).
+    attacher.patchStubCodePointer(*code);
+
+    // Update the failure path.
+    attacher.patchNextStubJump(masm, *code);
+
+    return LINK_GOOD;
+}
+
+bool
+IonCache::linkAndAttachStub(JSContext* cx, MacroAssembler& masm, StubAttacher& attacher,
+                            IonScript* ion, const char* attachKind,
+                            JS::TrackedOutcome trackedOutcome)
+{
+    CodeLocationJump lastJumpBefore = lastJump_;
+    Rooted<JitCode*> code(cx);
+    {
+        // Need to exit the AutoFlushICache context to flush the cache
+        // before attaching the stub below.
+        AutoFlushICache afc("IonCache");
+        LinkStatus status = linkCode(cx, masm, attacher, ion, code.address());
+        if (status != LINK_GOOD)
+            return status != LINK_ERROR;
+    }
+
+    if (pc_) {
+        JitSpew(JitSpew_IonIC, "Cache %p(%s:%" PRIuSIZE "/%" PRIuSIZE ") generated %s %s stub at %p",
+                this, script_->filename(), script_->lineno(), script_->pcToOffset(pc_),
+                attachKind, CacheName(kind()), code->raw());
+    } else {
+        JitSpew(JitSpew_IonIC, "Cache %p generated %s %s stub at %p",
+                this, attachKind, CacheName(kind()), code->raw());
+    }
+
+#ifdef JS_ION_PERF
+    writePerfSpewerJitCodeProfile(code, "IonCache");
+#endif
+
+    attachStub(masm, attacher, lastJumpBefore, code);
+
+    // Add entry to native => bytecode mapping for this stub if needed.
+    if (cx->runtime()->jitRuntime()->isProfilerInstrumentationEnabled(cx->runtime())) {
+        JitcodeGlobalEntry::IonCacheEntry entry;
+        entry.init(code, code->raw(), code->rawEnd(), rejoinAddress(), trackedOutcome);
+
+        // Add entry to the global table.
+        JitcodeGlobalTable* globalTable = cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
+        if (!globalTable->addEntry(entry, cx->runtime())) {
+            entry.destroy();
+            ReportOutOfMemory(cx);
+            return false;
+        }
+
+        // Mark the jitcode as having a bytecode map.
+        code->setHasBytecodeMap();
+    } else {
+        JitcodeGlobalEntry::DummyEntry entry;
+        entry.init(code, code->raw(), code->rawEnd());
+
+        // Add entry to the global table.
+        JitcodeGlobalTable* globalTable = cx->runtime()->jitRuntime()->getJitcodeGlobalTable();
+        if (!globalTable->addEntry(entry, cx->runtime())) {
+            entry.destroy();
+            ReportOutOfMemory(cx);
+            return false;
+        }
+
+        // Mark the jitcode as having a bytecode map.
+        code->setHasBytecodeMap();
+    }
+
+    // Report masm OOM errors here, so all our callers can:
+    // return linkAndAttachStub(...);
+    if (masm.oom()) {
+        ReportOutOfMemory(cx);
+        return false;
+    }
+
+    return true;
+}
+
+void
+IonCache::updateBaseAddress(JitCode* code, MacroAssembler& masm)
+{
+    fallbackLabel_.repoint(code, &masm);
+    initialJump_.repoint(code, &masm);
+    lastJump_.repoint(code, &masm);
+    rejoinLabel_.repoint(code, &masm);
+}
+
+void IonCache::trace(JSTracer* trc)
+{
+    if (script_)
+        TraceManuallyBarrieredEdge(trc, &script_, "IonCache::script_");
+}
+
+static void*
+GetReturnAddressToIonCode(JSContext* cx)
+{
+    JitFrameIterator iter(cx);
+    MOZ_ASSERT(iter.type() == JitFrame_Exit,
+               "An exit frame is expected as update functions are called with a VMFunction.");
+
+    void* returnAddr = iter.returnAddress();
+#ifdef DEBUG
+    ++iter;
+    MOZ_ASSERT(iter.isIonJS());
+#endif
+    return returnAddr;
+}
+
+static void
+GeneratePrototypeGuards(JSContext* cx, IonScript* ion, MacroAssembler& masm, JSObject* obj,
+                        JSObject* holder, Register objectReg, Register scratchReg,
+                        Label* failures)
+{
+    /*
+     * The guards here protect against the effects of JSObject::swap(). If the prototype chain
+     * is directly altered, then TI will toss the jitcode, so we don't have to worry about
+     * it, and any other change to the holder, or adding a shadowing property will result
+     * in reshaping the holder, and thus the failure of the shape guard.
+     */
+    MOZ_ASSERT(obj != holder);
+
+    if (obj->hasUncacheableProto()) {
+        // Note: objectReg and scratchReg may be the same register, so we cannot
+        // use objectReg in the rest of this function.
+        masm.loadPtr(Address(objectReg, JSObject::offsetOfGroup()), scratchReg);
+        Address proto(scratchReg, ObjectGroup::offsetOfProto());
+        masm.branchPtr(Assembler::NotEqual, proto, ImmGCPtr(obj->staticPrototype()), failures);
+    }
+
+    JSObject* pobj = obj->staticPrototype();
+    if (!pobj)
+        return;
+    while (pobj != holder) {
+        if (pobj->hasUncacheableProto()) {
+            masm.movePtr(ImmGCPtr(pobj), scratchReg);
+            Address groupAddr(scratchReg, JSObject::offsetOfGroup());
+            if (pobj->isSingleton()) {
+                // Singletons can have their group's |proto| mutated directly.
+                masm.loadPtr(groupAddr, scratchReg);
+                Address protoAddr(scratchReg, ObjectGroup::offsetOfProto());
+                masm.branchPtr(Assembler::NotEqual, protoAddr, ImmGCPtr(pobj->staticPrototype()),
+                              failures);
+            } else {
+                masm.branchPtr(Assembler::NotEqual, groupAddr, ImmGCPtr(pobj->group()), failures);
+            }
+        }
+
+        pobj = pobj->staticPrototype();
+    }
+}
+
+// Note: This differs from IsCacheableProtoChain in BaselineIC.cpp in that
+// Ion caches can deal with objects on the proto chain that have uncacheable
+// prototypes.
+bool
+jit::IsCacheableProtoChainForIonOrCacheIR(JSObject* obj, JSObject* holder)
+{
+    while (obj != holder) {
+        /*
+         * We cannot assume that we find the holder object on the prototype
+         * chain and must check for null proto. The prototype chain can be
+         * altered during the lookupProperty call.
+         */
+        JSObject* proto = obj->staticPrototype();
+        if (!proto || !proto->isNative())
+            return false;
+        obj = proto;
+    }
+    return true;
+}
+
+bool
+jit::IsCacheableGetPropReadSlotForIonOrCacheIR(JSObject* obj, JSObject* holder, Shape* shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (!shape->hasSlot() || !shape->hasDefaultGetter())
+        return false;
+
+    return true;
+}
+
+static bool
+IsCacheableNoProperty(JSObject* obj, JSObject* holder, Shape* shape, jsbytecode* pc,
+                      const TypedOrValueRegister& output)
+{
+    if (shape)
+        return false;
+
+    MOZ_ASSERT(!holder);
+
+    // Just because we didn't find the property on the object doesn't mean it
+    // won't magically appear through various engine hacks.
+    if (obj->getClass()->getGetProperty())
+        return false;
+
+    // Don't generate missing property ICs if we skipped a non-native object, as
+    // lookups may extend beyond the prototype chain (e.g. for DOMProxy
+    // proxies).
+    JSObject* obj2 = obj;
+    while (obj2) {
+        if (!obj2->isNative())
+            return false;
+        obj2 = obj2->staticPrototype();
+    }
+
+    // The pc is nullptr if the cache is idempotent. We cannot share missing
+    // properties between caches because TI can only try to prove that a type is
+    // contained, but does not attempts to check if something does not exists.
+    // So the infered type of getprop would be missing and would not contain
+    // undefined, as expected for missing properties.
+    if (!pc)
+        return false;
+
+    // TI has not yet monitored an Undefined value. The fallback path will
+    // monitor and invalidate the script.
+    if (!output.hasValue())
+        return false;
+
+    return true;
+}
+
+static bool
+IsOptimizableArgumentsObjectForLength(JSObject* obj)
+{
+    if (!obj->is<ArgumentsObject>())
+        return false;
+
+    if (obj->as<ArgumentsObject>().hasOverriddenLength())
+        return false;
+
+    return true;
+}
+
+static bool
+IsOptimizableArgumentsObjectForGetElem(JSObject* obj, const Value& idval)
+{
+    if (!IsOptimizableArgumentsObjectForLength(obj))
+        return false;
+
+    ArgumentsObject& argsObj = obj->as<ArgumentsObject>();
+
+    if (argsObj.isAnyElementDeleted())
+        return false;
+
+    if (argsObj.hasOverriddenElement())
+        return false;
+
+    if (!idval.isInt32())
+        return false;
+
+    int32_t idint = idval.toInt32();
+    if (idint < 0 || static_cast<uint32_t>(idint) >= argsObj.initialLength())
+        return false;
+
+    return true;
+}
+
+static bool
+IsCacheableGetPropCallNative(JSObject* obj, JSObject* holder, Shape* shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (!shape->hasGetterValue() || !shape->getterValue().isObject())
+        return false;
+
+    if (!shape->getterValue().toObject().is<JSFunction>())
+        return false;
+
+    JSFunction& getter = shape->getterValue().toObject().as<JSFunction>();
+    if (!getter.isNative())
+        return false;
+
+    // Check for a getter that has jitinfo and whose jitinfo says it's
+    // OK with both inner and outer objects.
+    if (getter.jitInfo() && !getter.jitInfo()->needsOuterizedThisObject())
+        return true;
+
+    // For getters that need the WindowProxy (instead of the Window) as this
+    // object, don't cache if obj is the Window, since our cache will pass that
+    // instead of the WindowProxy.
+    return !IsWindow(obj);
+}
+
+static bool
+IsCacheableGetPropCallScripted(JSObject* obj, JSObject* holder, Shape* shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (!shape->hasGetterValue() || !shape->getterValue().isObject())
+        return false;
+
+    if (!shape->getterValue().toObject().is<JSFunction>())
+        return false;
+
+    JSFunction& getter = shape->getterValue().toObject().as<JSFunction>();
+    if (!getter.hasJITCode())
+        return false;
+
+    // See IsCacheableGetPropCallNative.
+    return !IsWindow(obj);
+}
+
+static bool
+IsCacheableGetPropCallPropertyOp(JSObject* obj, JSObject* holder, Shape* shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (shape->hasSlot() || shape->hasGetterValue() || shape->hasDefaultGetter())
+        return false;
+
+    return true;
+}
+
+static void
+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<UnboxedArrayObject>()) {
+        MOZ_ASSERT(failure);
+        masm.branchTestObjGroup(Assembler::NotEqual, object, obj->group(), failure);
+    } else if (obj->is<TypedObject>()) {
+        attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                       Address(object, JSObject::offsetOfGroup()),
+                                       ImmGCPtr(obj->group()), failure);
+    } else {
+        Shape* shape = obj->maybeShape();
+        MOZ_ASSERT(shape);
+
+        attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                       Address(object, ShapedObject::offsetOfShape()),
+                                       ImmGCPtr(shape), failure);
+
+        if (alwaysCheckGroup)
+            masm.branchTestObjGroup(Assembler::NotEqual, object, obj->group(), failure);
+    }
+}
+
+static inline void
+EmitLoadSlot(MacroAssembler& masm, NativeObject* holder, Shape* shape, Register holderReg,
+             TypedOrValueRegister output, Register scratchReg)
+{
+    MOZ_ASSERT(holder);
+    NativeObject::slotsSizeMustNotOverflow();
+    if (holder->isFixedSlot(shape->slot())) {
+        Address addr(holderReg, NativeObject::getFixedSlotOffset(shape->slot()));
+        masm.loadTypedOrValue(addr, output);
+    } else {
+        masm.loadPtr(Address(holderReg, NativeObject::offsetOfSlots()), scratchReg);
+
+        Address addr(scratchReg, holder->dynamicSlotIndex(shape->slot()) * sizeof(Value));
+        masm.loadTypedOrValue(addr, output);
+    }
+}
+
+// Callers are expected to have already guarded on the shape of the
+// object, which guarantees the object is a DOM proxy.
+static void
+CheckDOMProxyExpandoDoesNotShadow(JSContext* cx, MacroAssembler& masm, JSObject* obj,
+                                  jsid id, Register object, Label* stubFailure)
+{
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+
+    // Guard that the object does not have expando properties, or has an expando
+    // which is known to not have the desired property.
+
+    // For the remaining code, we need to reserve some registers to load a value.
+    // This is ugly, but unvaoidable.
+    AllocatableRegisterSet domProxyRegSet(RegisterSet::All());
+    domProxyRegSet.take(AnyRegister(object));
+    ValueOperand tempVal = domProxyRegSet.takeAnyValue();
+    masm.pushValue(tempVal);
+
+    Label failDOMProxyCheck;
+    Label domProxyOk;
+
+    Value expandoVal = GetProxyExtra(obj, GetDOMProxyExpandoSlot());
+
+    masm.loadPtr(Address(object, ProxyObject::offsetOfValues()), tempVal.scratchReg());
+    masm.loadValue(Address(tempVal.scratchReg(),
+                           ProxyObject::offsetOfExtraSlotInValues(GetDOMProxyExpandoSlot())),
+                   tempVal);
+
+    if (!expandoVal.isObject() && !expandoVal.isUndefined()) {
+        masm.branchTestValue(Assembler::NotEqual, tempVal, expandoVal, &failDOMProxyCheck);
+
+        ExpandoAndGeneration* expandoAndGeneration = (ExpandoAndGeneration*)expandoVal.toPrivate();
+        masm.movePtr(ImmPtr(expandoAndGeneration), tempVal.scratchReg());
+
+        masm.branch64(Assembler::NotEqual,
+                      Address(tempVal.scratchReg(),
+                              ExpandoAndGeneration::offsetOfGeneration()),
+                      Imm64(expandoAndGeneration->generation),
+                      &failDOMProxyCheck);
+
+        expandoVal = expandoAndGeneration->expando;
+        masm.loadValue(Address(tempVal.scratchReg(),
+                               ExpandoAndGeneration::offsetOfExpando()),
+                       tempVal);
+    }
+
+    // If the incoming object does not have an expando object then we're sure we're not
+    // shadowing.
+    masm.branchTestUndefined(Assembler::Equal, tempVal, &domProxyOk);
+
+    if (expandoVal.isObject()) {
+        MOZ_ASSERT(!expandoVal.toObject().as<NativeObject>().contains(cx, id));
+
+        // Reference object has an expando object that doesn't define the name. Check that
+        // the incoming object has an expando object with the same shape.
+        masm.branchTestObject(Assembler::NotEqual, tempVal, &failDOMProxyCheck);
+        masm.extractObject(tempVal, tempVal.scratchReg());
+        masm.branchPtr(Assembler::Equal,
+                       Address(tempVal.scratchReg(), ShapedObject::offsetOfShape()),
+                       ImmGCPtr(expandoVal.toObject().as<NativeObject>().lastProperty()),
+                       &domProxyOk);
+    }
+
+    // Failure case: restore the tempVal registers and jump to failures.
+    masm.bind(&failDOMProxyCheck);
+    masm.popValue(tempVal);
+    masm.jump(stubFailure);
+
+    // Success case: restore the tempval and proceed.
+    masm.bind(&domProxyOk);
+    masm.popValue(tempVal);
+}
+
+static void
+GenerateReadSlot(JSContext* cx, IonScript* ion, MacroAssembler& masm,
+                 IonCache::StubAttacher& attacher, MaybeCheckTDZ checkTDZ,
+                 JSObject* obj, JSObject* holder, Shape* shape, Register object,
+                 TypedOrValueRegister output, Label* failures = nullptr)
+{
+    // If there's a single jump to |failures|, we can patch the shape guard
+    // 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());
+
+    // If we have multiple failure jumps but didn't get a label from the
+    // outside, make one ourselves.
+    Label failures_;
+    if (multipleFailureJumps && !failures)
+        failures = &failures_;
+
+    TestMatchingReceiver(masm, attacher, object, obj, failures);
+
+    // If we need a scratch register, use either an output register or the
+    // object register. After this point, we cannot jump directly to
+    // |failures| since we may still have to pop the object register.
+    bool restoreScratch = false;
+    Register scratchReg = Register::FromCode(0); // Quell compiler warning.
+
+    if (obj != holder ||
+        obj->is<UnboxedPlainObject>() ||
+        !holder->as<NativeObject>().isFixedSlot(shape->slot()))
+    {
+        if (output.hasValue()) {
+            scratchReg = output.valueReg().scratchReg();
+        } else if (output.type() == MIRType::Double) {
+            scratchReg = object;
+            masm.push(scratchReg);
+            restoreScratch = true;
+        } else {
+            scratchReg = output.typedReg().gpr();
+        }
+    }
+
+    // Fast path: single failure jump, no prototype guards.
+    if (!multipleFailureJumps) {
+        EmitLoadSlot(masm, &holder->as<NativeObject>(), shape, object, output, scratchReg);
+        if (restoreScratch)
+            masm.pop(scratchReg);
+        attacher.jumpRejoin(masm);
+        return;
+    }
+
+    // Slow path: multiple jumps; generate prototype guards.
+    Label prototypeFailures;
+    Register holderReg;
+    if (obj != holder) {
+        // Note: this may clobber the object register if it's used as scratch.
+        GeneratePrototypeGuards(cx, ion, masm, obj, holder, object, scratchReg,
+                                &prototypeFailures);
+
+        if (holder) {
+            // Guard on the holder's shape.
+            holderReg = scratchReg;
+            masm.movePtr(ImmGCPtr(holder), holderReg);
+            masm.branchPtr(Assembler::NotEqual,
+                           Address(holderReg, ShapedObject::offsetOfShape()),
+                           ImmGCPtr(holder->as<NativeObject>().lastProperty()),
+                           &prototypeFailures);
+        } else {
+            // The property does not exist. Guard on everything in the
+            // prototype chain.
+            JSObject* proto = obj->staticPrototype();
+            Register lastReg = object;
+            MOZ_ASSERT(scratchReg != object);
+            while (proto) {
+                masm.loadObjProto(lastReg, scratchReg);
+
+                // Guard the shape of the current prototype.
+                MOZ_ASSERT(proto->hasStaticPrototype());
+                masm.branchPtr(Assembler::NotEqual,
+                               Address(scratchReg, ShapedObject::offsetOfShape()),
+                               ImmGCPtr(proto->as<NativeObject>().lastProperty()),
+                               &prototypeFailures);
+
+                proto = proto->staticPrototype();
+                lastReg = scratchReg;
+            }
+
+            holderReg = InvalidReg;
+        }
+    } else if (obj->is<UnboxedPlainObject>()) {
+        holder = obj->as<UnboxedPlainObject>().maybeExpando();
+        holderReg = scratchReg;
+        masm.loadPtr(Address(object, UnboxedPlainObject::offsetOfExpando()), holderReg);
+    } else {
+        holderReg = object;
+    }
+
+    // Slot access.
+    if (holder) {
+        EmitLoadSlot(masm, &holder->as<NativeObject>(), shape, holderReg, output, scratchReg);
+        if (checkTDZ && output.hasValue())
+            masm.branchTestMagic(Assembler::Equal, output.valueReg(), failures);
+    } else {
+        masm.moveValue(UndefinedValue(), output.valueReg());
+    }
+
+    // Restore scratch on success.
+    if (restoreScratch)
+        masm.pop(scratchReg);
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(&prototypeFailures);
+    if (restoreScratch)
+        masm.pop(scratchReg);
+    masm.bind(failures);
+
+    attacher.jumpNextStub(masm);
+}
+
+static void
+GenerateReadUnboxed(JSContext* cx, IonScript* ion, MacroAssembler& masm,
+                    IonCache::StubAttacher& attacher, JSObject* obj,
+                    const UnboxedLayout::Property* property,
+                    Register object, TypedOrValueRegister output,
+                    Label* failures = nullptr)
+{
+    // Guard on the group of the object.
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                   Address(object, JSObject::offsetOfGroup()),
+                                   ImmGCPtr(obj->group()), failures);
+
+    Address address(object, UnboxedPlainObject::offsetOfData() + property->offset);
+
+    masm.loadUnboxedProperty(address, property->type, output);
+
+    attacher.jumpRejoin(masm);
+
+    if (failures) {
+        masm.bind(failures);
+        attacher.jumpNextStub(masm);
+    }
+}
+
+static bool
+EmitGetterCall(JSContext* cx, MacroAssembler& masm,
+               IonCache::StubAttacher& attacher, JSObject* obj,
+               JSObject* holder, HandleShape shape, bool holderIsReceiver,
+               LiveRegisterSet liveRegs, Register object,
+               TypedOrValueRegister output,
+               void* returnAddr)
+{
+    MOZ_ASSERT(output.hasValue());
+    MacroAssembler::AfterICSaveLive aic = masm.icSaveLive(liveRegs);
+
+    MOZ_ASSERT_IF(obj != holder, !holderIsReceiver);
+
+    // Remaining registers should basically be free, but we need to use |object| still
+    // so leave it alone.
+    AllocatableRegisterSet regSet(RegisterSet::All());
+    regSet.take(AnyRegister(object));
+
+    // This is a slower stub path, and we're going to be doing a call anyway.  Don't need
+    // to try so hard to not use the stack.  Scratch regs are just taken from the register
+    // set not including the input, current value saved on the stack, and restored when
+    // we're done with it.
+    Register scratchReg = regSet.takeAnyGeneral();
+
+    // Shape has a JSNative, PropertyOp or scripted getter function.
+    if (IsCacheableGetPropCallNative(obj, holder, shape)) {
+        Register argJSContextReg = regSet.takeAnyGeneral();
+        Register argUintNReg     = regSet.takeAnyGeneral();
+        Register argVpReg        = regSet.takeAnyGeneral();
+
+        JSFunction* target = &shape->getterValue().toObject().as<JSFunction>();
+        MOZ_ASSERT(target);
+        MOZ_ASSERT(target->isNative());
+
+        // Native functions have the signature:
+        //  bool (*)(JSContext*, unsigned, Value* vp)
+        // Where vp[0] is space for an outparam, vp[1] is |this|, and vp[2] onward
+        // are the function arguments.
+
+        // Construct vp array:
+        // Push object value for |this|
+        masm.Push(TypedOrValueRegister(MIRType::Object, AnyRegister(object)));
+        // Push callee/outparam.
+        masm.Push(ObjectValue(*target));
+
+        // Preload arguments into registers.
+        masm.loadJSContext(argJSContextReg);
+        masm.move32(Imm32(0), argUintNReg);
+        masm.moveStackPtrTo(argVpReg);
+
+        // Push marking data for later use.
+        masm.Push(argUintNReg);
+        attacher.pushStubCodePointer(masm);
+
+        if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+            return false;
+        masm.enterFakeExitFrame(IonOOLNativeExitFrameLayoutToken);
+
+        // Construct and execute call.
+        masm.setupUnalignedABICall(scratchReg);
+        masm.passABIArg(argJSContextReg);
+        masm.passABIArg(argUintNReg);
+        masm.passABIArg(argVpReg);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, target->native()));
+
+        // Test for failure.
+        masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+        // Load the outparam vp[0] into output register(s).
+        Address outparam(masm.getStackPointer(), IonOOLNativeExitFrameLayout::offsetOfResult());
+        masm.loadTypedOrValue(outparam, output);
+
+        // masm.leaveExitFrame & pop locals
+        masm.adjustStack(IonOOLNativeExitFrameLayout::Size(0));
+    } else if (IsCacheableGetPropCallPropertyOp(obj, holder, shape)) {
+        Register argJSContextReg = regSet.takeAnyGeneral();
+        Register argObjReg       = regSet.takeAnyGeneral();
+        Register argIdReg        = regSet.takeAnyGeneral();
+        Register argVpReg        = regSet.takeAnyGeneral();
+
+        GetterOp target = shape->getterOp();
+        MOZ_ASSERT(target);
+
+        // Push stubCode for marking.
+        attacher.pushStubCodePointer(masm);
+
+        // JSGetterOp: bool fn(JSContext* cx, HandleObject obj, HandleId id, MutableHandleValue vp)
+
+        // Push args on stack first so we can take pointers to make handles.
+        masm.Push(UndefinedValue());
+        masm.moveStackPtrTo(argVpReg);
+
+        // Push canonical jsid from shape instead of propertyname.
+        masm.Push(shape->propid(), scratchReg);
+        masm.moveStackPtrTo(argIdReg);
+
+        // Push the holder.
+        if (holderIsReceiver) {
+            // When the holder is also the current receiver, we just have a shape guard,
+            // so we might end up with a random object which is also guaranteed to have
+            // this JSGetterOp.
+            masm.Push(object);
+        } else {
+            // If the holder is on the prototype chain, the prototype-guarding
+            // only allows objects with the same holder.
+            masm.movePtr(ImmGCPtr(holder), scratchReg);
+            masm.Push(scratchReg);
+        }
+        masm.moveStackPtrTo(argObjReg);
+
+        masm.loadJSContext(argJSContextReg);
+
+        if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+            return false;
+        masm.enterFakeExitFrame(IonOOLPropertyOpExitFrameLayoutToken);
+
+        // Make the call.
+        masm.setupUnalignedABICall(scratchReg);
+        masm.passABIArg(argJSContextReg);
+        masm.passABIArg(argObjReg);
+        masm.passABIArg(argIdReg);
+        masm.passABIArg(argVpReg);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, target));
+
+        // Test for failure.
+        masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+        // Load the outparam vp[0] into output register(s).
+        Address outparam(masm.getStackPointer(), IonOOLPropertyOpExitFrameLayout::offsetOfResult());
+        masm.loadTypedOrValue(outparam, output);
+
+        // masm.leaveExitFrame & pop locals.
+        masm.adjustStack(IonOOLPropertyOpExitFrameLayout::Size());
+    } else {
+        MOZ_ASSERT(IsCacheableGetPropCallScripted(obj, holder, shape));
+
+        JSFunction* target = &shape->getterValue().toObject().as<JSFunction>();
+        uint32_t framePushedBefore = masm.framePushed();
+
+        // Construct IonAccessorICFrameLayout.
+        uint32_t descriptor = MakeFrameDescriptor(masm.framePushed(), JitFrame_IonJS,
+                                                  IonAccessorICFrameLayout::Size());
+        attacher.pushStubCodePointer(masm);
+        masm.Push(Imm32(descriptor));
+        masm.Push(ImmPtr(returnAddr));
+
+        // The JitFrameLayout pushed below will be aligned to JitStackAlignment,
+        // so we just have to make sure the stack is aligned after we push the
+        // |this| + argument Values.
+        uint32_t argSize = (target->nargs() + 1) * sizeof(Value);
+        uint32_t padding = ComputeByteAlignment(masm.framePushed() + argSize, JitStackAlignment);
+        MOZ_ASSERT(padding % sizeof(uintptr_t) == 0);
+        MOZ_ASSERT(padding < JitStackAlignment);
+        masm.reserveStack(padding);
+
+        for (size_t i = 0; i < target->nargs(); i++)
+            masm.Push(UndefinedValue());
+        masm.Push(TypedOrValueRegister(MIRType::Object, AnyRegister(object)));
+
+        masm.movePtr(ImmGCPtr(target), scratchReg);
+
+        descriptor = MakeFrameDescriptor(argSize + padding, JitFrame_IonAccessorIC,
+                                         JitFrameLayout::Size());
+        masm.Push(Imm32(0)); // argc
+        masm.Push(scratchReg);
+        masm.Push(Imm32(descriptor));
+
+        // Check stack alignment. Add sizeof(uintptr_t) for the return address.
+        MOZ_ASSERT(((masm.framePushed() + sizeof(uintptr_t)) % JitStackAlignment) == 0);
+
+        // The getter has JIT code now and we will only discard the getter's JIT
+        // code when discarding all JIT code in the Zone, so we can assume it'll
+        // still have JIT code.
+        MOZ_ASSERT(target->hasJITCode());
+        masm.loadPtr(Address(scratchReg, JSFunction::offsetOfNativeOrScript()), scratchReg);
+        masm.loadBaselineOrIonRaw(scratchReg, scratchReg, nullptr);
+        masm.callJit(scratchReg);
+        masm.storeCallResultValue(output);
+
+        masm.freeStack(masm.framePushed() - framePushedBefore);
+    }
+
+    masm.icRestoreLive(liveRegs, aic);
+    return true;
+}
+
+static bool
+GenerateCallGetter(JSContext* cx, IonScript* ion, MacroAssembler& masm,
+                   IonCache::StubAttacher& attacher, JSObject* obj,
+                   JSObject* holder, HandleShape shape, LiveRegisterSet& liveRegs, Register object,
+                   TypedOrValueRegister output, void* returnAddr, Label* failures = nullptr)
+{
+    MOZ_ASSERT(output.hasValue());
+
+    // Use the passed in label if there was one. Otherwise, we'll have to make our own.
+    Label stubFailure;
+    failures = failures ? failures : &stubFailure;
+
+    TestMatchingReceiver(masm, attacher, object, obj, failures);
+
+    Register scratchReg = output.valueReg().scratchReg();
+    bool spillObjReg = scratchReg == object;
+    Label pop1AndFail;
+    Label* maybePopAndFail = failures;
+
+    // If we're calling a getter on the global, inline the logic for the
+    // 'this' hook on the global lexical env and manually push the global.
+    if (IsGlobalLexicalEnvironment(obj)) {
+        masm.extractObject(Address(object, EnvironmentObject::offsetOfEnclosingEnvironment()),
+                           object);
+    }
+
+    // Save off the object register if it aliases the scratchReg
+    if (spillObjReg) {
+        masm.push(object);
+        maybePopAndFail = &pop1AndFail;
+    }
+
+    // Note: this may clobber the object register if it's used as scratch.
+    if (obj != holder)
+        GeneratePrototypeGuards(cx, ion, masm, obj, holder, object, scratchReg, maybePopAndFail);
+
+    // Guard on the holder's shape.
+    Register holderReg = scratchReg;
+    masm.movePtr(ImmGCPtr(holder), holderReg);
+    masm.branchPtr(Assembler::NotEqual,
+                   Address(holderReg, ShapedObject::offsetOfShape()),
+                   ImmGCPtr(holder->as<NativeObject>().lastProperty()),
+                   maybePopAndFail);
+
+    if (spillObjReg)
+        masm.pop(object);
+
+    // Now we're good to go to invoke the native call.
+    bool holderIsReceiver = (obj == holder);
+    if (!EmitGetterCall(cx, masm, attacher, obj, holder, shape, holderIsReceiver, liveRegs, object,
+                        output, returnAddr))
+        return false;
+
+    // Rejoin jump.
+    attacher.jumpRejoin(masm);
+
+    // Jump to next stub.
+    if (spillObjReg) {
+        masm.bind(&pop1AndFail);
+        masm.pop(object);
+    }
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+
+    return true;
+}
+
+static bool
+GenerateArrayLength(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                    JSObject* obj, Register object, TypedOrValueRegister output, Label* failures)
+{
+    MOZ_ASSERT(obj->is<ArrayObject>());
+
+    // Guard object is a dense array.
+    RootedShape shape(cx, obj->as<ArrayObject>().lastProperty());
+    if (!shape)
+        return false;
+    masm.branchTestObjShape(Assembler::NotEqual, object, shape, failures);
+
+    // Load length.
+    Register outReg;
+    if (output.hasValue()) {
+        outReg = output.valueReg().scratchReg();
+    } else {
+        MOZ_ASSERT(output.type() == MIRType::Int32);
+        outReg = output.typedReg().gpr();
+    }
+
+    masm.loadPtr(Address(object, NativeObject::offsetOfElements()), outReg);
+    masm.load32(Address(outReg, ObjectElements::offsetOfLength()), outReg);
+
+    // The length is an unsigned int, but the value encodes a signed int.
+    MOZ_ASSERT(object != outReg);
+    masm.branchTest32(Assembler::Signed, outReg, outReg, failures);
+
+    if (output.hasValue())
+        masm.tagValue(JSVAL_TYPE_INT32, outReg, output.valueReg());
+
+    /* Success. */
+    attacher.jumpRejoin(masm);
+
+    /* Failure. */
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+
+    return true;
+}
+
+static void
+GenerateUnboxedArrayLength(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                           JSObject* array, Register object, TypedOrValueRegister output,
+                           Label* failures)
+{
+    Register outReg;
+    if (output.hasValue()) {
+        outReg = output.valueReg().scratchReg();
+    } else {
+        MOZ_ASSERT(output.type() == MIRType::Int32);
+        outReg = output.typedReg().gpr();
+    }
+    MOZ_ASSERT(object != outReg);
+
+    TestMatchingReceiver(masm, attacher, object, array, failures);
+
+    // Load length.
+    masm.load32(Address(object, UnboxedArrayObject::offsetOfLength()), outReg);
+
+    // Check for a length that fits in an int32.
+    masm.branchTest32(Assembler::Signed, outReg, outReg, failures);
+
+    if (output.hasValue())
+        masm.tagValue(JSVAL_TYPE_INT32, outReg, output.valueReg());
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+}
+
+// In this case, the code for TypedArray and SharedTypedArray is not the same,
+// because the code embeds pointers to the respective class arrays.  Code that
+// caches the stub code must distinguish between the two cases.
+static void
+GenerateTypedArrayLength(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                         Register object, TypedOrValueRegister output, Label* failures)
+{
+    Register tmpReg;
+    if (output.hasValue()) {
+        tmpReg = output.valueReg().scratchReg();
+    } else {
+        MOZ_ASSERT(output.type() == MIRType::Int32);
+        tmpReg = output.typedReg().gpr();
+    }
+    MOZ_ASSERT(object != tmpReg);
+
+    // Implement the negated version of JSObject::isTypedArray predicate.
+    masm.loadObjClass(object, tmpReg);
+    masm.branchPtr(Assembler::Below, tmpReg, ImmPtr(&TypedArrayObject::classes[0]),
+                   failures);
+    masm.branchPtr(Assembler::AboveOrEqual, tmpReg,
+                   ImmPtr(&TypedArrayObject::classes[Scalar::MaxTypedArrayViewType]),
+                   failures);
+
+    // Load length.
+    masm.loadTypedOrValue(Address(object, TypedArrayObject::lengthOffset()), output);
+
+    /* Success. */
+    attacher.jumpRejoin(masm);
+
+    /* Failure. */
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+}
+
+static bool
+IsCacheableArrayLength(JSContext* cx, HandleObject obj, TypedOrValueRegister output)
+{
+    if (!obj->is<ArrayObject>())
+        return false;
+
+    if (output.type() != MIRType::Value && output.type() != MIRType::Int32) {
+        // The stub assumes that we always output Int32, so make sure our output
+        // is equipped to handle that.
+        return false;
+    }
+
+    // The emitted stub can only handle int32 lengths. If the length of the
+    // actual object does not fit in an int32 then don't attach a stub, as if
+    // the cache is idempotent we won't end up invalidating the compiled script
+    // otherwise.
+    if (obj->as<ArrayObject>().length() > INT32_MAX)
+        return false;
+
+    return true;
+}
+
+template <class GetPropCache>
+static GetPropertyIC::NativeGetPropCacheability
+CanAttachNativeGetProp(JSContext* cx, const GetPropCache& cache,
+                       HandleObject obj, HandleId id,
+                       MutableHandleNativeObject holder, MutableHandleShape shape,
+                       bool skipArrayLen = false)
+{
+    MOZ_ASSERT(JSID_IS_STRING(id) || JSID_IS_SYMBOL(id));
+
+    if (!obj)
+        return GetPropertyIC::CanAttachNone;
+
+    // The lookup needs to be universally pure, otherwise we risk calling hooks out
+    // of turn. We don't mind doing this even when purity isn't required, because we
+    // only miss out on shape hashification, which is only a temporary perf cost.
+    // The limits were arbitrarily set, anyways.
+    JSObject* baseHolder = nullptr;
+    if (!LookupPropertyPure(cx, obj, id, &baseHolder, shape.address()))
+        return GetPropertyIC::CanAttachNone;
+
+    MOZ_ASSERT(!holder);
+    if (baseHolder) {
+        if (!baseHolder->isNative())
+            return GetPropertyIC::CanAttachNone;
+        holder.set(&baseHolder->as<NativeObject>());
+    }
+
+    RootedScript script(cx);
+    jsbytecode* pc;
+    cache.getScriptedLocation(&script, &pc);
+    if (IsCacheableGetPropReadSlotForIonOrCacheIR(obj, holder, shape) ||
+        IsCacheableNoProperty(obj, holder, shape, pc, cache.output()))
+    {
+        return GetPropertyIC::CanAttachReadSlot;
+    }
+
+    // |length| is a non-configurable getter property on ArrayObjects. Any time this
+    // check would have passed, we can install a getter stub instead. Allow people to
+    // make that decision themselves with skipArrayLen
+    if (!skipArrayLen && JSID_IS_ATOM(id, cx->names().length) && cache.allowArrayLength(cx) &&
+        IsCacheableArrayLength(cx, obj, cache.output()))
+    {
+        // The array length property is non-configurable, which means both that
+        // checking the class of the object and the name of the property is enough
+        // and that we don't need to worry about monitoring, since we know the
+        // return type statically.
+        return GetPropertyIC::CanAttachArrayLength;
+    }
+
+    // IonBuilder guarantees that it's impossible to generate a GetPropertyIC with
+    // allowGetters() true and cache.output().hasValue() false. If this isn't true,
+    // we will quickly assert during stub generation.
+    //
+    // Be careful when adding support for other getters here: for outer window
+    // proxies, IonBuilder can innerize and pass us the inner window (the global),
+    // see IonBuilder::getPropTryInnerize. This is fine for native/scripted getters
+    // because IsCacheableGetPropCallNative and IsCacheableGetPropCallScripted
+    // handle this.
+    if (cache.allowGetters() &&
+        (IsCacheableGetPropCallNative(obj, holder, shape) ||
+         IsCacheableGetPropCallPropertyOp(obj, holder, shape) ||
+         IsCacheableGetPropCallScripted(obj, holder, shape)))
+    {
+        // Don't enable getter call if cache is idempotent, since they can be
+        // effectful. This is handled by allowGetters()
+        return GetPropertyIC::CanAttachCallGetter;
+    }
+
+    return GetPropertyIC::CanAttachNone;
+}
+
+static bool
+EqualStringsHelper(JSString* str1, JSString* str2)
+{
+    MOZ_ASSERT(str1->isAtom());
+    MOZ_ASSERT(!str2->isAtom());
+    MOZ_ASSERT(str1->length() == str2->length());
+
+    JSLinearString* str2Linear = str2->ensureLinear(nullptr);
+    if (!str2Linear)
+        return false;
+
+    return EqualChars(&str1->asLinear(), str2Linear);
+}
+
+static void
+EmitIdGuard(MacroAssembler& masm, jsid id, TypedOrValueRegister idReg, Register objReg,
+            Register scratchReg, Label* failures)
+{
+    MOZ_ASSERT(JSID_IS_STRING(id) || JSID_IS_SYMBOL(id));
+
+    MOZ_ASSERT(idReg.type() == MIRType::String ||
+               idReg.type() == MIRType::Symbol ||
+               idReg.type() == MIRType::Value);
+
+    Register payloadReg;
+    if (idReg.type() == MIRType::Value) {
+        ValueOperand val = idReg.valueReg();
+        if (JSID_IS_SYMBOL(id)) {
+            masm.branchTestSymbol(Assembler::NotEqual, val, failures);
+        } else {
+            MOZ_ASSERT(JSID_IS_STRING(id));
+            masm.branchTestString(Assembler::NotEqual, val, failures);
+        }
+        masm.unboxNonDouble(val, scratchReg);
+        payloadReg = scratchReg;
+    } else {
+        payloadReg = idReg.typedReg().gpr();
+    }
+
+    if (JSID_IS_SYMBOL(id)) {
+        // For symbols, we can just do a pointer comparison.
+        masm.branchPtr(Assembler::NotEqual, payloadReg, ImmGCPtr(JSID_TO_SYMBOL(id)), failures);
+    } else {
+        PropertyName* name = JSID_TO_ATOM(id)->asPropertyName();
+
+        Label equal;
+        masm.branchPtr(Assembler::Equal, payloadReg, ImmGCPtr(name), &equal);
+
+        // The pointers are not equal, so if the input string is also an atom it
+        // must be a different string.
+        masm.branchTest32(Assembler::NonZero, Address(payloadReg, JSString::offsetOfFlags()),
+                          Imm32(JSString::ATOM_BIT), failures);
+
+        // Check the length.
+        masm.branch32(Assembler::NotEqual, Address(payloadReg, JSString::offsetOfLength()),
+                      Imm32(name->length()), failures);
+
+        // We have a non-atomized string with the same length. For now call a helper
+        // function to do the comparison.
+        LiveRegisterSet volatileRegs(RegisterSet::Volatile());
+        masm.PushRegsInMask(volatileRegs);
+
+        if (!volatileRegs.has(objReg))
+            masm.push(objReg);
+
+        masm.setupUnalignedABICall(objReg);
+        masm.movePtr(ImmGCPtr(name), objReg);
+        masm.passABIArg(objReg);
+        masm.passABIArg(payloadReg);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, EqualStringsHelper));
+        masm.mov(ReturnReg, scratchReg);
+
+        if (!volatileRegs.has(objReg))
+            masm.pop(objReg);
+
+        LiveRegisterSet ignore;
+        ignore.add(scratchReg);
+        masm.PopRegsInMaskIgnore(volatileRegs, ignore);
+
+        masm.branchIfFalseBool(scratchReg, failures);
+        masm.bind(&equal);
+    }
+}
+
+void
+GetPropertyIC::emitIdGuard(MacroAssembler& masm, jsid id, Label* fail)
+{
+    if (this->id().constant())
+        return;
+
+    Register scratch = output().valueReg().scratchReg();
+    EmitIdGuard(masm, id, this->id().reg(), object(), scratch, fail);
+}
+
+void
+SetPropertyIC::emitIdGuard(MacroAssembler& masm, jsid id, Label* fail)
+{
+    if (this->id().constant())
+        return;
+
+    EmitIdGuard(masm, id, this->id().reg(), object(), temp(), fail);
+}
+
+bool
+GetPropertyIC::allowArrayLength(JSContext* cx) const
+{
+    if (!idempotent())
+        return true;
+
+    uint32_t locationIndex, numLocations;
+    getLocationInfo(&locationIndex, &numLocations);
+
+    IonScript* ion = GetTopJitJSScript(cx)->ionScript();
+    CacheLocation* locs = ion->getCacheLocs(locationIndex);
+    for (size_t i = 0; i < numLocations; i++) {
+        CacheLocation& curLoc = locs[i];
+        StackTypeSet* bcTypes = TypeScript::BytecodeTypes(curLoc.script, curLoc.pc);
+
+        if (!bcTypes->hasType(TypeSet::Int32Type()))
+            return false;
+    }
+
+    return true;
+}
+
+bool
+GetPropertyIC::tryAttachNative(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                               HandleObject obj, HandleId id, void* returnAddr, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(outerScript->ionScript() == ion);
+
+    RootedShape shape(cx);
+    RootedNativeObject holder(cx);
+
+    NativeGetPropCacheability type =
+        CanAttachNativeGetProp(cx, *this, obj, id, &holder, &shape);
+    if (type == CanAttachNone)
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+
+    StubAttacher attacher(*this);
+    const char* attachKind;
+
+    JS::TrackedOutcome outcome = JS::TrackedOutcome::ICOptStub_GenericSuccess;
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+    Label* maybeFailures = failures.used() ? &failures : nullptr;
+
+    switch (type) {
+      case CanAttachReadSlot:
+        GenerateReadSlot(cx, ion, masm, attacher, DontCheckTDZ, obj, holder,
+                         shape, object(), output(), maybeFailures);
+        attachKind = idempotent() ? "idempotent reading"
+                                    : "non idempotent reading";
+        outcome = JS::TrackedOutcome::ICGetPropStub_ReadSlot;
+        break;
+      case CanAttachCallGetter:
+        if (!GenerateCallGetter(cx, ion, masm, attacher, obj, holder, shape,
+                                liveRegs_, object(), output(), returnAddr, maybeFailures))
+        {
+            return false;
+        }
+        attachKind = "getter call";
+        outcome = JS::TrackedOutcome::ICGetPropStub_CallGetter;
+        break;
+      case CanAttachArrayLength:
+        if (!GenerateArrayLength(cx, masm, attacher, obj, object(), output(), &failures))
+            return false;
+
+        attachKind = "array length";
+        outcome = JS::TrackedOutcome::ICGetPropStub_ArrayLength;
+        break;
+      default:
+        MOZ_CRASH("Bad NativeGetPropCacheability");
+    }
+    return linkAndAttachStub(cx, masm, attacher, ion, attachKind, outcome);
+}
+
+bool
+GetPropertyIC::tryAttachUnboxed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                HandleObject obj, HandleId id, void* returnAddr, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(outerScript->ionScript() == ion);
+
+    if (!obj->is<UnboxedPlainObject>())
+        return true;
+    const UnboxedLayout::Property* property = obj->as<UnboxedPlainObject>().layout().lookup(id);
+    if (!property)
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+    Label* maybeFailures = failures.used() ? &failures : nullptr;
+
+    StubAttacher attacher(*this);
+    GenerateReadUnboxed(cx, ion, masm, attacher, obj, property, object(), output(), maybeFailures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "read unboxed",
+                             JS::TrackedOutcome::ICGetPropStub_UnboxedRead);
+}
+
+bool
+GetPropertyIC::tryAttachUnboxedExpando(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                       HandleObject obj, HandleId id, void* returnAddr, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(outerScript->ionScript() == ion);
+
+    if (!obj->is<UnboxedPlainObject>())
+        return true;
+    Rooted<UnboxedExpandoObject*> expando(cx, obj->as<UnboxedPlainObject>().maybeExpando());
+    if (!expando)
+        return true;
+
+    Shape* shape = expando->lookup(cx, id);
+    if (!shape || !shape->hasDefaultGetter() || !shape->hasSlot())
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+    Label* maybeFailures = failures.used() ? &failures : nullptr;
+
+    StubAttacher attacher(*this);
+    GenerateReadSlot(cx, ion, masm, attacher, DontCheckTDZ, obj, obj,
+                     shape, object(), output(), maybeFailures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "read unboxed expando",
+                             JS::TrackedOutcome::ICGetPropStub_UnboxedReadExpando);
+}
+
+bool
+GetPropertyIC::tryAttachUnboxedArrayLength(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                           HandleObject obj, HandleId id, void* returnAddr,
+                                           bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(outerScript->ionScript() == ion);
+
+    if (!obj->is<UnboxedArrayObject>())
+        return true;
+
+    if (!JSID_IS_ATOM(id, cx->names().length))
+        return true;
+
+    if (obj->as<UnboxedArrayObject>().length() > INT32_MAX)
+        return true;
+
+    if (!allowArrayLength(cx))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+
+    StubAttacher attacher(*this);
+    GenerateUnboxedArrayLength(cx, masm, attacher, obj, object(), output(), &failures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "unboxed array length",
+                             JS::TrackedOutcome::ICGetPropStub_UnboxedArrayLength);
+}
+
+bool
+GetPropertyIC::tryAttachTypedArrayLength(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                         HandleObject obj, HandleId id, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!obj->is<TypedArrayObject>())
+        return true;
+
+    if (!JSID_IS_ATOM(id, cx->names().length))
+        return true;
+
+    if (hasTypedArrayLengthStub(obj))
+        return true;
+
+    if (output().type() != MIRType::Value && output().type() != MIRType::Int32) {
+        // The next execution should cause an invalidation because the type
+        // does not fit.
+        return true;
+    }
+
+    if (idempotent())
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+
+    GenerateTypedArrayLength(cx, masm, attacher, object(), output(), &failures);
+
+    setHasTypedArrayLengthStub(obj);
+    return linkAndAttachStub(cx, masm, attacher, ion, "typed array length",
+                             JS::TrackedOutcome::ICGetPropStub_TypedArrayLength);
+}
+
+static void
+PushObjectOpResult(MacroAssembler& masm)
+{
+    static_assert(sizeof(ObjectOpResult) == sizeof(uintptr_t),
+                  "ObjectOpResult size must match size reserved by masm.Push() here");
+    masm.Push(ImmWord(ObjectOpResult::Uninitialized));
+}
+
+static bool
+ProxyGetProperty(JSContext* cx, HandleObject proxy, HandleId id, MutableHandleValue vp)
+{
+    RootedValue receiver(cx, ObjectValue(*proxy));
+    return Proxy::get(cx, proxy, receiver, id, vp);
+}
+
+static bool
+EmitCallProxyGet(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                 jsid id, LiveRegisterSet liveRegs, Register object, TypedOrValueRegister output,
+                 jsbytecode* pc, void* returnAddr)
+{
+    MOZ_ASSERT(output.hasValue());
+    MacroAssembler::AfterICSaveLive aic = masm.icSaveLive(liveRegs);
+
+    // Remaining registers should be free, but we need to use |object| still
+    // so leave it alone.
+    AllocatableRegisterSet regSet(RegisterSet::All());
+    regSet.take(AnyRegister(object));
+
+    // ProxyGetProperty(JSContext* cx, HandleObject proxy, HandleId id,
+    //                  MutableHandleValue vp)
+    Register argJSContextReg = regSet.takeAnyGeneral();
+    Register argProxyReg     = regSet.takeAnyGeneral();
+    Register argIdReg        = regSet.takeAnyGeneral();
+    Register argVpReg        = regSet.takeAnyGeneral();
+
+    Register scratch         = regSet.takeAnyGeneral();
+
+    // Push stubCode for marking.
+    attacher.pushStubCodePointer(masm);
+
+    // Push args on stack first so we can take pointers to make handles.
+    masm.Push(UndefinedValue());
+    masm.moveStackPtrTo(argVpReg);
+
+    masm.Push(id, scratch);
+    masm.moveStackPtrTo(argIdReg);
+
+    // Push the proxy. Also used as receiver.
+    masm.Push(object);
+    masm.moveStackPtrTo(argProxyReg);
+
+    masm.loadJSContext(argJSContextReg);
+
+    if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+        return false;
+    masm.enterFakeExitFrame(IonOOLProxyExitFrameLayoutToken);
+
+    // Make the call.
+    masm.setupUnalignedABICall(scratch);
+    masm.passABIArg(argJSContextReg);
+    masm.passABIArg(argProxyReg);
+    masm.passABIArg(argIdReg);
+    masm.passABIArg(argVpReg);
+    masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, ProxyGetProperty));
+
+    // Test for failure.
+    masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+    // Load the outparam vp[0] into output register(s).
+    Address outparam(masm.getStackPointer(), IonOOLProxyExitFrameLayout::offsetOfResult());
+    masm.loadTypedOrValue(outparam, output);
+
+    // masm.leaveExitFrame & pop locals
+    masm.adjustStack(IonOOLProxyExitFrameLayout::Size());
+
+    masm.icRestoreLive(liveRegs, aic);
+    return true;
+}
+
+bool
+GetPropertyIC::tryAttachDOMProxyShadowed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                         HandleObject obj, HandleId id, void* returnAddr,
+                                         bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+    MOZ_ASSERT(monitoredResult());
+    MOZ_ASSERT(output().hasValue());
+
+    if (idempotent())
+        return true;
+
+    *emitted = true;
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    // Guard on the shape of the object.
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                   Address(object(), ShapedObject::offsetOfShape()),
+                                   ImmGCPtr(obj->maybeShape()),
+                                   &failures);
+
+    // No need for more guards: we know this is a DOM proxy, since the shape
+    // guard enforces a given JSClass, so just go ahead and emit the call to
+    // ProxyGet.
+
+    if (!EmitCallProxyGet(cx, masm, attacher, id, liveRegs_, object(), output(),
+                          pc(), returnAddr))
+    {
+        return false;
+    }
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "list base shadowed get",
+                             JS::TrackedOutcome::ICGetPropStub_DOMProxyShadowed);
+}
+
+bool
+GetPropertyIC::tryAttachDOMProxyUnshadowed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                           HandleObject obj, HandleId id, bool resetNeeded,
+                                           void* returnAddr, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+    MOZ_ASSERT(monitoredResult());
+    MOZ_ASSERT(output().hasValue());
+
+    RootedObject checkObj(cx, obj->staticPrototype());
+    RootedNativeObject holder(cx);
+    RootedShape shape(cx);
+
+    NativeGetPropCacheability canCache =
+        CanAttachNativeGetProp(cx, *this, checkObj, id, &holder, &shape,
+                               /* skipArrayLen = */true);
+    MOZ_ASSERT(canCache != CanAttachArrayLength);
+
+    if (canCache == CanAttachNone)
+        return true;
+
+    // Make sure we observe our invariants if we're gonna deoptimize.
+    if (!holder && idempotent())
+        return true;
+
+    *emitted = true;
+
+    if (resetNeeded) {
+        // If we know that we have a DoesntShadowUnique object, then
+        // we reset the cache to clear out an existing IC for the object
+        // (if there is one). The generation is a constant in the generated
+        // code and we will not have the same generation again for this
+        // object, so the generation check in the existing IC would always
+        // fail anyway.
+        reset(Reprotect);
+    }
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    // Guard on the shape of the object.
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                   Address(object(), ShapedObject::offsetOfShape()),
+                                   ImmGCPtr(obj->maybeShape()),
+                                   &failures);
+
+    // Guard that our expando object hasn't started shadowing this property.
+    CheckDOMProxyExpandoDoesNotShadow(cx, masm, obj, id, object(), &failures);
+
+    if (holder) {
+        // Found the property on the prototype chain. Treat it like a native
+        // getprop.
+        Register scratchReg = output().valueReg().scratchReg();
+        GeneratePrototypeGuards(cx, ion, masm, obj, holder, object(), scratchReg, &failures);
+
+        // Rename scratch for clarity.
+        Register holderReg = scratchReg;
+
+        // Guard on the holder of the property
+        masm.movePtr(ImmGCPtr(holder), holderReg);
+        masm.branchPtr(Assembler::NotEqual,
+                    Address(holderReg, ShapedObject::offsetOfShape()),
+                    ImmGCPtr(holder->lastProperty()),
+                    &failures);
+
+        if (canCache == CanAttachReadSlot) {
+            EmitLoadSlot(masm, holder, shape, holderReg, output(), scratchReg);
+        } else {
+            // EmitGetterCall() expects |obj| to be the object the property is
+            // on to do some checks. Since we actually looked at checkObj, and
+            // no extra guards will be generated, we can just pass that instead.
+            // The holderIsReceiver check needs to use |obj| though.
+            MOZ_ASSERT(canCache == CanAttachCallGetter);
+            MOZ_ASSERT(!idempotent());
+            bool holderIsReceiver = (obj == holder);
+            if (!EmitGetterCall(cx, masm, attacher, checkObj, holder, shape, holderIsReceiver,
+                                liveRegs_, object(), output(), returnAddr))
+            {
+                return false;
+            }
+        }
+    } else {
+        // Property was not found on the prototype chain. Deoptimize down to
+        // proxy get call
+        MOZ_ASSERT(!idempotent());
+        if (!EmitCallProxyGet(cx, masm, attacher, id, liveRegs_, object(), output(),
+                              pc(), returnAddr))
+        {
+            return false;
+        }
+    }
+
+    attacher.jumpRejoin(masm);
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "unshadowed proxy get",
+                             JS::TrackedOutcome::ICGetPropStub_DOMProxyUnshadowed);
+}
+
+bool
+GetPropertyIC::tryAttachProxy(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                              HandleObject obj, HandleId id, void* returnAddr, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!obj->is<ProxyObject>())
+        return true;
+
+    // TI can't be sure about our properties, so make sure anything
+    // we return can be monitored directly.
+    if (!monitoredResult())
+        return true;
+
+    // Skim off DOM proxies.
+    if (IsCacheableDOMProxy(obj)) {
+        DOMProxyShadowsResult shadows = GetDOMProxyShadowsCheck()(cx, obj, id);
+        if (shadows == ShadowCheckFailed)
+            return false;
+        if (DOMProxyIsShadowing(shadows))
+            return tryAttachDOMProxyShadowed(cx, outerScript, ion, obj, id, returnAddr, emitted);
+
+        MOZ_ASSERT(shadows == DoesntShadow || shadows == DoesntShadowUnique);
+        return tryAttachDOMProxyUnshadowed(cx, outerScript, ion, obj, id,
+                                           shadows == DoesntShadowUnique, returnAddr, emitted);
+    }
+
+    return tryAttachGenericProxy(cx, outerScript, ion, obj, id, returnAddr, emitted);
+}
+
+bool
+GetPropertyIC::tryAttachGenericProxy(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                     HandleObject obj, HandleId id, void* returnAddr,
+                                     bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(obj->is<ProxyObject>());
+    MOZ_ASSERT(monitoredResult());
+    MOZ_ASSERT(output().hasValue());
+
+    if (hasGenericProxyStub())
+        return true;
+
+    if (idempotent())
+        return true;
+
+    *emitted = true;
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    Register scratchReg = output().valueReg().scratchReg();
+
+    masm.branchTestObjectIsProxy(false, object(), scratchReg, &failures);
+
+    // Ensure that the incoming object is not a DOM proxy, so that we can get to
+    // the specialized stubs
+    masm.branchTestProxyHandlerFamily(Assembler::Equal, object(), scratchReg,
+                                      GetDOMProxyHandlerFamily(), &failures);
+
+    if (!EmitCallProxyGet(cx, masm, attacher, id, liveRegs_, object(), output(),
+                          pc(), returnAddr))
+    {
+        return false;
+    }
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    MOZ_ASSERT(!hasGenericProxyStub_);
+    hasGenericProxyStub_ = true;
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "Generic Proxy get",
+                             JS::TrackedOutcome::ICGetPropStub_GenericProxy);
+}
+
+bool
+GetPropertyIC::tryAttachArgumentsLength(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                        HandleObject obj, HandleId id, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!JSID_IS_ATOM(id, cx->names().length))
+        return true;
+    if (!IsOptimizableArgumentsObjectForLength(obj))
+        return true;
+
+    MIRType outputType = output().type();
+    if (!(outputType == MIRType::Value || outputType == MIRType::Int32))
+        return true;
+
+    if (hasArgumentsLengthStub(obj->is<MappedArgumentsObject>()))
+        return true;
+
+    *emitted = true;
+
+    MOZ_ASSERT(!idempotent());
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    Register tmpReg;
+    if (output().hasValue()) {
+        tmpReg = output().valueReg().scratchReg();
+    } else {
+        MOZ_ASSERT(output().type() == MIRType::Int32);
+        tmpReg = output().typedReg().gpr();
+    }
+    MOZ_ASSERT(object() != tmpReg);
+
+    masm.branchTestObjClass(Assembler::NotEqual, object(), tmpReg, obj->getClass(), &failures);
+
+    // Get initial ArgsObj length value, test if length has been overridden.
+    masm.unboxInt32(Address(object(), ArgumentsObject::getInitialLengthSlotOffset()), tmpReg);
+    masm.branchTest32(Assembler::NonZero, tmpReg, Imm32(ArgumentsObject::LENGTH_OVERRIDDEN_BIT),
+                      &failures);
+
+    masm.rshiftPtr(Imm32(ArgumentsObject::PACKED_BITS_COUNT), tmpReg);
+
+    // If output is Int32, result is already in right place, otherwise box it into output.
+    if (output().hasValue())
+        masm.tagValue(JSVAL_TYPE_INT32, tmpReg, output().valueReg());
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    if (obj->is<UnmappedArgumentsObject>()) {
+        MOZ_ASSERT(!hasUnmappedArgumentsLengthStub_);
+        hasUnmappedArgumentsLengthStub_ = true;
+        return linkAndAttachStub(cx, masm, attacher, ion, "ArgsObj length (unmapped)",
+                                 JS::TrackedOutcome::ICGetPropStub_ArgumentsLength);
+    }
+
+    MOZ_ASSERT(!hasMappedArgumentsLengthStub_);
+    hasMappedArgumentsLengthStub_ = true;
+    return linkAndAttachStub(cx, masm, attacher, ion, "ArgsObj length (mapped)",
+                                 JS::TrackedOutcome::ICGetPropStub_ArgumentsLength);
+}
+
+static void
+GenerateReadModuleNamespace(JSContext* cx, IonScript* ion, MacroAssembler& masm,
+                            IonCache::StubAttacher& attacher, ModuleNamespaceObject* ns,
+                            ModuleEnvironmentObject* env, Shape* shape, Register object,
+                            TypedOrValueRegister output, Label* failures)
+{
+    MOZ_ASSERT(ns);
+    MOZ_ASSERT(env);
+
+    // If we have multiple failure jumps but didn't get a label from the
+    // outside, make one ourselves.
+    Label failures_;
+    if (!failures)
+        failures = &failures_;
+
+    // Check for the specific namespace object.
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual, object, ImmGCPtr(ns), failures);
+
+    // If we need a scratch register, use either an output register or the
+    // object register.
+    bool restoreScratch = false;
+    Register scratchReg = InvalidReg; // Quell compiler warning.
+
+    if (output.hasValue()) {
+        scratchReg = output.valueReg().scratchReg();
+    } else if (output.type() == MIRType::Double) {
+        masm.push(object);
+        scratchReg = object;
+        restoreScratch = true;
+    } else {
+        scratchReg = output.typedReg().gpr();
+    }
+
+    // Slot access.
+    Register envReg = scratchReg;
+    masm.movePtr(ImmGCPtr(env), envReg);
+    EmitLoadSlot(masm, &env->as<NativeObject>(), shape, envReg, output, scratchReg);
+
+    // Restore scratch on success.
+    if (restoreScratch)
+        masm.pop(object);
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+}
+
+bool
+GetPropertyIC::tryAttachModuleNamespace(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                        HandleObject obj, HandleId id, void* returnAddr,
+                                        bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(outerScript->ionScript() == ion);
+
+    if (!obj->is<ModuleNamespaceObject>())
+        return true;
+
+    Rooted<ModuleNamespaceObject*> ns(cx, &obj->as<ModuleNamespaceObject>());
+
+    RootedModuleEnvironmentObject env(cx);
+    RootedShape shape(cx);
+    if (!ns->bindings().lookup(id, env.address(), shape.address()))
+        return true;
+
+    // Don't emit a stub until the target binding has been initialized.
+    if (env->getSlot(shape->slot()).isMagic(JS_UNINITIALIZED_LEXICAL))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+    Label* maybeFailures = failures.used() ? &failures : nullptr;
+
+    GenerateReadModuleNamespace(cx, ion, masm, attacher, ns, env,
+                                shape, object(), output(), maybeFailures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "module namespace",
+                             JS::TrackedOutcome::ICGetPropStub_ReadSlot);
+}
+
+static bool
+ValueToNameOrSymbolId(JSContext* cx, HandleValue idval, MutableHandleId id, bool* nameOrSymbol)
+{
+    *nameOrSymbol = false;
+
+    if (!idval.isString() && !idval.isSymbol())
+        return true;
+
+    if (!ValueToId<CanGC>(cx, idval, id))
+        return false;
+
+    if (!JSID_IS_STRING(id) && !JSID_IS_SYMBOL(id)) {
+        id.set(JSID_VOID);
+        return true;
+    }
+
+    uint32_t dummy;
+    if (JSID_IS_STRING(id) && JSID_TO_ATOM(id)->isIndex(&dummy)) {
+        id.set(JSID_VOID);
+        return true;
+    }
+
+    *nameOrSymbol = true;
+    return true;
+}
+
+bool
+GetPropertyIC::tryAttachStub(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                             HandleObject obj, HandleValue idval, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+
+    if (!canAttachStub())
+        return true;
+
+    RootedId id(cx);
+    bool nameOrSymbol;
+    if (!ValueToNameOrSymbolId(cx, idval, &id, &nameOrSymbol))
+        return false;
+
+    if (nameOrSymbol) {
+        if (!*emitted && !tryAttachArgumentsLength(cx, outerScript, ion, obj, id, emitted))
+            return false;
+
+        void* returnAddr = GetReturnAddressToIonCode(cx);
+
+        if (!*emitted && !tryAttachModuleNamespace(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachProxy(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachNative(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachUnboxed(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachUnboxedExpando(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachUnboxedArrayLength(cx, outerScript, ion, obj, id, returnAddr, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachTypedArrayLength(cx, outerScript, ion, obj, id, emitted))
+            return false;
+    }
+
+    if (idval.isInt32()) {
+        if (!*emitted && !tryAttachArgumentsElement(cx, outerScript, ion, obj, idval, emitted))
+            return false;
+        if (!*emitted && !tryAttachDenseElement(cx, outerScript, ion, obj, idval, emitted))
+            return false;
+        if (!*emitted && !tryAttachDenseElementHole(cx, outerScript, ion, obj, idval, emitted))
+            return false;
+    }
+
+    if (idval.isInt32() || idval.isString()) {
+        if (!*emitted && !tryAttachTypedOrUnboxedArrayElement(cx, outerScript, ion, obj, idval, emitted))
+            return false;
+    }
+
+    if (!*emitted)
+        JitSpew(JitSpew_IonIC, "Failed to attach GETPROP cache");
+
+    return true;
+}
+
+/* static */ bool
+GetPropertyIC::update(JSContext* cx, HandleScript outerScript, size_t cacheIndex,
+                      HandleObject obj, HandleValue idval, MutableHandleValue vp)
+{
+    IonScript* ion = outerScript->ionScript();
+
+    GetPropertyIC& cache = ion->getCache(cacheIndex).toGetProperty();
+
+    // Override the return value if we are invalidated (bug 728188).
+    AutoDetectInvalidation adi(cx, vp, ion);
+
+    // If the cache is idempotent, we will redo the op in the interpreter.
+    if (cache.idempotent())
+        adi.disable();
+
+    // For now, just stop generating new stubs once we hit the stub count
+    // limit. Once we can make calls from within generated stubs, a new call
+    // stub will be generated instead and the previous stubs unlinked.
+    bool emitted = false;
+    if (!cache.isDisabled()) {
+        if (!cache.tryAttachStub(cx, outerScript, ion, obj, idval, &emitted))
+            return false;
+        cache.maybeDisable(emitted);
+    }
+
+    if (cache.idempotent() && !emitted) {
+        // Invalidate the cache if the property was not found, or was found on
+        // a non-native object. This ensures:
+        // 1) The property read has no observable side-effects.
+        // 2) There's no need to dynamically monitor the return type. This would
+        //    be complicated since (due to GVN) there can be multiple pc's
+        //    associated with a single idempotent cache.
+        JitSpew(JitSpew_IonIC, "Invalidating from idempotent cache %s:%" PRIuSIZE,
+                outerScript->filename(), outerScript->lineno());
+
+        outerScript->setInvalidatedIdempotentCache();
+
+        // Do not re-invalidate if the lookup already caused invalidation.
+        if (outerScript->hasIonScript())
+            Invalidate(cx, outerScript);
+
+        return true;
+    }
+
+    jsbytecode* pc = cache.idempotent() ? nullptr : cache.pc();
+
+    if (!pc || *pc == JSOP_GETPROP || *pc == JSOP_CALLPROP || *pc == JSOP_LENGTH) {
+        if (!GetProperty(cx, obj, obj, idval.toString()->asAtom().asPropertyName(), vp))
+            return false;
+    } else {
+        MOZ_ASSERT(*pc == JSOP_GETELEM || *pc == JSOP_CALLELEM);
+        if (!GetObjectElementOperation(cx, JSOp(*pc), obj, obj, idval, vp))
+            return false;
+    }
+
+    if (!cache.idempotent()) {
+        RootedScript script(cx);
+        jsbytecode* pc;
+        cache.getScriptedLocation(&script, &pc);
+
+        // Monitor changes to cache entry.
+        if (!cache.monitoredResult())
+            TypeScript::Monitor(cx, script, pc, vp);
+    }
+
+    return true;
+}
+
+void
+GetPropertyIC::reset(ReprotectCode reprotect)
+{
+    IonCache::reset(reprotect);
+    hasTypedArrayLengthStub_ = false;
+    hasMappedArgumentsLengthStub_ = false;
+    hasUnmappedArgumentsLengthStub_ = false;
+    hasMappedArgumentsElementStub_ = false;
+    hasUnmappedArgumentsElementStub_ = false;
+    hasGenericProxyStub_ = false;
+    hasDenseStub_ = false;
+}
+
+void
+IonCache::disable()
+{
+    reset(Reprotect);
+    this->disabled_ = 1;
+}
+
+void
+GetPropertyIC::maybeDisable(bool emitted)
+{
+    if (emitted) {
+        failedUpdates_ = 0;
+        return;
+    }
+
+    if (!canAttachStub() && id().constant()) {
+        // Don't disable the cache (and discard stubs) if we have a GETPROP and
+        // attached the maximum number of stubs. This can happen when JS code
+        // uses an AST-like data structure and accesses a field of a "base
+        // class", like node.nodeType. This should be temporary until we handle
+        // this case better, see bug 1107515.
+        return;
+    }
+
+    if (++failedUpdates_ > MAX_FAILED_UPDATES) {
+        JitSpew(JitSpew_IonIC, "Disable inline cache");
+        disable();
+    }
+}
+
+void
+IonCache::reset(ReprotectCode reprotect)
+{
+    this->stubCount_ = 0;
+    PatchJump(initialJump_, fallbackLabel_, reprotect);
+    lastJump_ = initialJump_;
+}
+
+// Jump to failure if a value being written is not a property for obj/id.
+static void
+CheckTypeSetForWrite(MacroAssembler& masm, JSObject* obj, jsid id,
+                     Register scratch, const ConstantOrRegister& value, Label* failure)
+{
+    TypedOrValueRegister valReg = value.reg();
+    ObjectGroup* group = obj->group();
+    MOZ_ASSERT(!group->unknownProperties());
+
+    HeapTypeSet* propTypes = group->maybeGetProperty(id);
+    MOZ_ASSERT(propTypes);
+
+    // guardTypeSet can read from type sets without triggering read barriers.
+    TypeSet::readBarrier(propTypes);
+
+    masm.guardTypeSet(valReg, propTypes, BarrierKind::TypeSet, scratch, failure);
+}
+
+static void
+GenerateSetSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                JSObject* obj, Shape* shape, Register object, Register tempReg,
+                const ConstantOrRegister& value, bool needsTypeBarrier, bool checkTypeset,
+                Label* failures)
+{
+    TestMatchingReceiver(masm, attacher, object, obj, failures, needsTypeBarrier);
+
+    // Guard that the incoming value is in the type set for the property
+    // if a type barrier is required.
+    if (checkTypeset) {
+        MOZ_ASSERT(needsTypeBarrier);
+        CheckTypeSetForWrite(masm, obj, shape->propid(), tempReg, value, failures);
+    }
+
+    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()));
+
+        if (cx->zone()->needsIncrementalBarrier())
+            masm.callPreBarrier(addr, MIRType::Value);
+
+        masm.storeConstantOrRegister(value, addr);
+    } else {
+        masm.loadPtr(Address(object, NativeObject::offsetOfSlots()), tempReg);
+
+        Address addr(tempReg, obj->as<NativeObject>().dynamicSlotIndex(shape->slot()) * sizeof(Value));
+
+        if (cx->zone()->needsIncrementalBarrier())
+            masm.callPreBarrier(addr, MIRType::Value);
+
+        masm.storeConstantOrRegister(value, addr);
+    }
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+}
+
+bool
+SetPropertyIC::attachSetSlot(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                             HandleObject obj, HandleShape shape, bool checkTypeset)
+{
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, shape->propid(), &failures);
+
+    GenerateSetSlot(cx, masm, attacher, obj, shape, object(), temp(), value(), needsTypeBarrier(),
+                    checkTypeset, &failures);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "setting",
+                             JS::TrackedOutcome::ICSetPropStub_Slot);
+}
+
+static bool
+IsCacheableSetPropCallNative(HandleObject obj, HandleObject holder, HandleShape shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (!shape->hasSetterValue())
+        return false;
+
+    if (!shape->setterObject() || !shape->setterObject()->is<JSFunction>())
+        return false;
+
+    JSFunction& setter = shape->setterObject()->as<JSFunction>();
+    if (!setter.isNative())
+        return false;
+
+    if (setter.jitInfo() && !setter.jitInfo()->needsOuterizedThisObject())
+        return true;
+
+    return !IsWindow(obj);
+}
+
+static bool
+IsCacheableSetPropCallScripted(HandleObject obj, HandleObject holder, HandleShape shape)
+{
+    if (!shape || !IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (IsWindow(obj))
+        return false;
+
+    return shape->hasSetterValue() && shape->setterObject() &&
+           shape->setterObject()->is<JSFunction>() &&
+           shape->setterObject()->as<JSFunction>().hasJITCode();
+}
+
+static bool
+IsCacheableSetPropCallPropertyOp(HandleObject obj, HandleObject holder, HandleShape shape)
+{
+    if (!shape)
+        return false;
+
+    if (!IsCacheableProtoChainForIonOrCacheIR(obj, holder))
+        return false;
+
+    if (shape->hasSlot())
+        return false;
+
+    if (shape->hasDefaultSetter())
+        return false;
+
+    if (shape->hasSetterValue())
+        return false;
+
+    // Despite the vehement claims of Shape.h that writable() is only relevant
+    // for data descriptors, some SetterOps care desperately about its
+    // value. The flag should be always true, apart from these rare instances.
+    if (!shape->writable())
+        return false;
+
+    return true;
+}
+
+static bool
+ReportStrictErrorOrWarning(JSContext* cx, JS::HandleObject obj, JS::HandleId id, bool strict,
+                           JS::ObjectOpResult& result)
+{
+    return result.reportStrictErrorOrWarning(cx, obj, id, strict);
+}
+
+template <class FrameLayout>
+void
+EmitObjectOpResultCheck(MacroAssembler& masm, Label* failure, bool strict,
+                        Register scratchReg,
+                        Register argJSContextReg,
+                        Register argObjReg,
+                        Register argIdReg,
+                        Register argStrictReg,
+                        Register argResultReg)
+{
+    // if (!result) {
+    Label noStrictError;
+    masm.branch32(Assembler::Equal,
+                  Address(masm.getStackPointer(),
+                          FrameLayout::offsetOfObjectOpResult()),
+                  Imm32(ObjectOpResult::OkCode),
+                  &noStrictError);
+
+    //     if (!ReportStrictErrorOrWarning(cx, obj, id, strict, &result))
+    //         goto failure;
+    masm.loadJSContext(argJSContextReg);
+    masm.computeEffectiveAddress(
+        Address(masm.getStackPointer(), FrameLayout::offsetOfObject()),
+        argObjReg);
+    masm.computeEffectiveAddress(
+        Address(masm.getStackPointer(), FrameLayout::offsetOfId()),
+        argIdReg);
+    masm.move32(Imm32(strict), argStrictReg);
+    masm.computeEffectiveAddress(
+        Address(masm.getStackPointer(), FrameLayout::offsetOfObjectOpResult()),
+        argResultReg);
+    masm.setupUnalignedABICall(scratchReg);
+    masm.passABIArg(argJSContextReg);
+    masm.passABIArg(argObjReg);
+    masm.passABIArg(argIdReg);
+    masm.passABIArg(argStrictReg);
+    masm.passABIArg(argResultReg);
+    masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, ReportStrictErrorOrWarning));
+    masm.branchIfFalseBool(ReturnReg, failure);
+
+    // }
+    masm.bind(&noStrictError);
+}
+
+static bool
+ProxySetProperty(JSContext* cx, HandleObject proxy, HandleId id, HandleValue v, bool strict)
+{
+    RootedValue receiver(cx, ObjectValue(*proxy));
+    ObjectOpResult result;
+    return Proxy::set(cx, proxy, id, v, receiver, result)
+           && result.checkStrictErrorOrWarning(cx, proxy, id, strict);
+}
+
+static bool
+EmitCallProxySet(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                 HandleId propId, LiveRegisterSet liveRegs, Register object,
+                 const ConstantOrRegister& value, void* returnAddr, bool strict)
+{
+    MacroAssembler::AfterICSaveLive aic = masm.icSaveLive(liveRegs);
+
+    // Remaining registers should be free, but we still need to use |object| so
+    // leave it alone.
+    //
+    // WARNING: We do not take() the register used by |value|, if any, so
+    // regSet is going to re-allocate it. Hence the emitted code must not touch
+    // any of the registers allocated from regSet until after the last use of
+    // |value|. (We can't afford to take it, either, because x86.)
+    AllocatableRegisterSet regSet(RegisterSet::All());
+    regSet.take(AnyRegister(object));
+
+    // ProxySetProperty(JSContext* cx, HandleObject proxy, HandleId id, HandleValue v,
+    //                  bool strict);
+    Register argJSContextReg = regSet.takeAnyGeneral();
+    Register argProxyReg     = regSet.takeAnyGeneral();
+    Register argIdReg        = regSet.takeAnyGeneral();
+    Register argValueReg     = regSet.takeAnyGeneral();
+    Register argStrictReg    = regSet.takeAnyGeneral();
+
+    Register scratch         = regSet.takeAnyGeneral();
+
+    // Push stubCode for marking.
+    attacher.pushStubCodePointer(masm);
+
+    // Push args on stack so we can take pointers to make handles.
+    // Push value before touching any other registers (see WARNING above).
+    masm.Push(value);
+    masm.moveStackPtrTo(argValueReg);
+
+    masm.move32(Imm32(strict), argStrictReg);
+
+    masm.Push(propId, scratch);
+    masm.moveStackPtrTo(argIdReg);
+
+    // Push object.
+    masm.Push(object);
+    masm.moveStackPtrTo(argProxyReg);
+
+    masm.loadJSContext(argJSContextReg);
+
+    if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+        return false;
+    masm.enterFakeExitFrame(IonOOLProxyExitFrameLayoutToken);
+
+    // Make the call.
+    masm.setupUnalignedABICall(scratch);
+    masm.passABIArg(argJSContextReg);
+    masm.passABIArg(argProxyReg);
+    masm.passABIArg(argIdReg);
+    masm.passABIArg(argValueReg);
+    masm.passABIArg(argStrictReg);
+    masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, ProxySetProperty));
+
+    // Test for error.
+    masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+    // masm.leaveExitFrame & pop locals
+    masm.adjustStack(IonOOLProxyExitFrameLayout::Size());
+
+    masm.icRestoreLive(liveRegs, aic);
+    return true;
+}
+
+bool
+SetPropertyIC::attachGenericProxy(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                  HandleId id, void* returnAddr)
+{
+    MOZ_ASSERT(!hasGenericProxyStub());
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+    {
+        masm.branchTestObjectIsProxy(false, object(), temp(), &failures);
+
+        // Remove the DOM proxies. They'll take care of themselves so this stub doesn't
+        // catch too much. The failure case is actually Equal. Fall through to the failure code.
+        masm.branchTestProxyHandlerFamily(Assembler::Equal, object(), temp(),
+                                          GetDOMProxyHandlerFamily(), &failures);
+    }
+
+    if (!EmitCallProxySet(cx, masm, attacher, id, liveRegs_, object(), value(),
+                          returnAddr, strict()))
+    {
+        return false;
+    }
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    MOZ_ASSERT(!hasGenericProxyStub_);
+    hasGenericProxyStub_ = true;
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "generic proxy set",
+                             JS::TrackedOutcome::ICSetPropStub_GenericProxy);
+}
+
+bool
+SetPropertyIC::attachDOMProxyShadowed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                      HandleObject obj, HandleId id, void* returnAddr)
+{
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    // Guard on the shape of the object.
+    masm.branchPtr(Assembler::NotEqual,
+                   Address(object(), ShapedObject::offsetOfShape()),
+                   ImmGCPtr(obj->maybeShape()), &failures);
+
+    // No need for more guards: we know this is a DOM proxy, since the shape
+    // guard enforces a given JSClass, so just go ahead and emit the call to
+    // ProxySet.
+
+    if (!EmitCallProxySet(cx, masm, attacher, id, liveRegs_, object(),
+                          value(), returnAddr, strict()))
+    {
+        return false;
+    }
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "DOM proxy shadowed set",
+                             JS::TrackedOutcome::ICSetPropStub_DOMProxyShadowed);
+}
+
+static bool
+GenerateCallSetter(JSContext* cx, IonScript* ion, MacroAssembler& masm,
+                   IonCache::StubAttacher& attacher, HandleObject obj, HandleObject holder,
+                   HandleShape shape, bool strict, Register object, Register tempReg,
+                   const ConstantOrRegister& value, Label* failure, LiveRegisterSet liveRegs,
+                   void* returnAddr)
+{
+    // Generate prototype guards if needed.
+    {
+        // Generate prototype/shape guards.
+        if (obj != holder)
+            GeneratePrototypeGuards(cx, ion, masm, obj, holder, object, tempReg, failure);
+
+        masm.movePtr(ImmGCPtr(holder), tempReg);
+        masm.branchPtr(Assembler::NotEqual,
+                       Address(tempReg, ShapedObject::offsetOfShape()),
+                       ImmGCPtr(holder->as<NativeObject>().lastProperty()),
+                       failure);
+    }
+
+    // Good to go for invoking setter.
+
+    MacroAssembler::AfterICSaveLive aic = masm.icSaveLive(liveRegs);
+
+    // Remaining registers should basically be free, but we need to use |object| still
+    // so leave it alone.  And of course we need our value, if it's not a constant.
+    AllocatableRegisterSet regSet(RegisterSet::All());
+    if (!value.constant())
+        regSet.take(value.reg());
+    bool valueAliasesObject = !regSet.has(object);
+    if (!valueAliasesObject)
+        regSet.take(object);
+
+    regSet.take(tempReg);
+
+    // This is a slower stub path, and we're going to be doing a call anyway.  Don't need
+    // to try so hard to not use the stack.  Scratch regs are just taken from the register
+    // set not including the input, current value saved on the stack, and restored when
+    // we're done with it.
+    //
+    // Be very careful not to use any of these before value is pushed, since they
+    // might shadow.
+
+    if (IsCacheableSetPropCallNative(obj, holder, shape)) {
+        Register argJSContextReg = regSet.takeAnyGeneral();
+        Register argVpReg        = regSet.takeAnyGeneral();
+
+        MOZ_ASSERT(shape->hasSetterValue() && shape->setterObject() &&
+                   shape->setterObject()->is<JSFunction>());
+        JSFunction* target = &shape->setterObject()->as<JSFunction>();
+
+        MOZ_ASSERT(target->isNative());
+
+        Register argUintNReg = regSet.takeAnyGeneral();
+
+        // Set up the call:
+        //  bool (*)(JSContext*, unsigned, Value* vp)
+        // vp[0] is callee/outparam
+        // vp[1] is |this|
+        // vp[2] is the value
+
+        // Build vp and move the base into argVpReg.
+        masm.Push(value);
+        masm.Push(TypedOrValueRegister(MIRType::Object, AnyRegister(object)));
+        masm.Push(ObjectValue(*target));
+        masm.moveStackPtrTo(argVpReg);
+
+        // Preload other regs
+        masm.loadJSContext(argJSContextReg);
+        masm.move32(Imm32(1), argUintNReg);
+
+        // Push data for GC marking
+        masm.Push(argUintNReg);
+        attacher.pushStubCodePointer(masm);
+
+        if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+            return false;
+        masm.enterFakeExitFrame(IonOOLNativeExitFrameLayoutToken);
+
+        // Make the call
+        masm.setupUnalignedABICall(tempReg);
+        masm.passABIArg(argJSContextReg);
+        masm.passABIArg(argUintNReg);
+        masm.passABIArg(argVpReg);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, target->native()));
+
+        // Test for failure.
+        masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+        // masm.leaveExitFrame & pop locals.
+        masm.adjustStack(IonOOLNativeExitFrameLayout::Size(1));
+    } else if (IsCacheableSetPropCallPropertyOp(obj, holder, shape)) {
+        // We can't take all our registers up front, because on x86 we need 2
+        // for the value, one for scratch, 5 for the arguments, which makes 8,
+        // but we only have 7 to work with.  So only grab the ones we need
+        // before we push value and release its reg back into the set.
+        Register argResultReg = regSet.takeAnyGeneral();
+
+        SetterOp target = shape->setterOp();
+        MOZ_ASSERT(target);
+
+        // JSSetterOp: bool fn(JSContext* cx, HandleObject obj,
+        //                     HandleId id, HandleValue value, ObjectOpResult& result);
+
+        // First, allocate an ObjectOpResult on the stack. We push this before
+        // the stubCode pointer in order to match the layout of
+        // IonOOLSetterOpExitFrameLayout.
+        PushObjectOpResult(masm);
+        masm.moveStackPtrTo(argResultReg);
+
+        attacher.pushStubCodePointer(masm);
+
+        // Push args on stack so we can take pointers to make handles.
+        if (value.constant()) {
+            masm.Push(value.value());
+        } else {
+            masm.Push(value.reg());
+            if (!valueAliasesObject)
+                regSet.add(value.reg());
+        }
+
+        // OK, now we can grab our remaining registers and grab the pointer to
+        // what we just pushed into one of them.
+        Register argJSContextReg = regSet.takeAnyGeneral();
+        Register argValueReg     = regSet.takeAnyGeneral();
+        // We can just reuse the "object" register for argObjReg
+        Register argObjReg       = object;
+        Register argIdReg        = regSet.takeAnyGeneral();
+        masm.moveStackPtrTo(argValueReg);
+
+        // push canonical jsid from shape instead of propertyname.
+        masm.Push(shape->propid(), argIdReg);
+        masm.moveStackPtrTo(argIdReg);
+
+        masm.Push(object);
+        masm.moveStackPtrTo(argObjReg);
+
+        masm.loadJSContext(argJSContextReg);
+
+        if (!masm.icBuildOOLFakeExitFrame(returnAddr, aic))
+            return false;
+        masm.enterFakeExitFrame(IonOOLSetterOpExitFrameLayoutToken);
+
+        // Make the call.
+        masm.setupUnalignedABICall(tempReg);
+        masm.passABIArg(argJSContextReg);
+        masm.passABIArg(argObjReg);
+        masm.passABIArg(argIdReg);
+        masm.passABIArg(argValueReg);
+        masm.passABIArg(argResultReg);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, target));
+
+        // Test for error.
+        masm.branchIfFalseBool(ReturnReg, masm.exceptionLabel());
+
+        // Test for strict failure. We emit the check even in non-strict mode
+        // in order to pick up the warning if extraWarnings is enabled.
+        EmitObjectOpResultCheck<IonOOLSetterOpExitFrameLayout>(masm, masm.exceptionLabel(),
+                                                               strict, tempReg,
+                                                               argJSContextReg, argObjReg,
+                                                               argIdReg, argValueReg,
+                                                               argResultReg);
+
+        // masm.leaveExitFrame & pop locals.
+        masm.adjustStack(IonOOLSetterOpExitFrameLayout::Size());
+    } else {
+        MOZ_ASSERT(IsCacheableSetPropCallScripted(obj, holder, shape));
+
+        JSFunction* target = &shape->setterValue().toObject().as<JSFunction>();
+        uint32_t framePushedBefore = masm.framePushed();
+
+        // Construct IonAccessorICFrameLayout.
+        uint32_t descriptor = MakeFrameDescriptor(masm.framePushed(), JitFrame_IonJS,
+                                                  IonAccessorICFrameLayout::Size());
+        attacher.pushStubCodePointer(masm);
+        masm.Push(Imm32(descriptor));
+        masm.Push(ImmPtr(returnAddr));
+
+        // The JitFrameLayout pushed below will be aligned to JitStackAlignment,
+        // so we just have to make sure the stack is aligned after we push the
+        // |this| + argument Values.
+        uint32_t numArgs = Max(size_t(1), target->nargs());
+        uint32_t argSize = (numArgs + 1) * sizeof(Value);
+        uint32_t padding = ComputeByteAlignment(masm.framePushed() + argSize, JitStackAlignment);
+        MOZ_ASSERT(padding % sizeof(uintptr_t) == 0);
+        MOZ_ASSERT(padding < JitStackAlignment);
+        masm.reserveStack(padding);
+
+        for (size_t i = 1; i < target->nargs(); i++)
+            masm.Push(UndefinedValue());
+        masm.Push(value);
+        masm.Push(TypedOrValueRegister(MIRType::Object, AnyRegister(object)));
+
+        masm.movePtr(ImmGCPtr(target), tempReg);
+
+        descriptor = MakeFrameDescriptor(argSize + padding, JitFrame_IonAccessorIC,
+                                         JitFrameLayout::Size());
+        masm.Push(Imm32(1)); // argc
+        masm.Push(tempReg);
+        masm.Push(Imm32(descriptor));
+
+        // Check stack alignment. Add sizeof(uintptr_t) for the return address.
+        MOZ_ASSERT(((masm.framePushed() + sizeof(uintptr_t)) % JitStackAlignment) == 0);
+
+        // The setter has JIT code now and we will only discard the setter's JIT
+        // code when discarding all JIT code in the Zone, so we can assume it'll
+        // still have JIT code.
+        MOZ_ASSERT(target->hasJITCode());
+        masm.loadPtr(Address(tempReg, JSFunction::offsetOfNativeOrScript()), tempReg);
+        masm.loadBaselineOrIonRaw(tempReg, tempReg, nullptr);
+        masm.callJit(tempReg);
+
+        masm.freeStack(masm.framePushed() - framePushedBefore);
+    }
+
+    masm.icRestoreLive(liveRegs, aic);
+    return true;
+}
+
+static bool
+IsCacheableDOMProxyUnshadowedSetterCall(JSContext* cx, HandleObject obj, HandleId id,
+                                        MutableHandleObject holder, MutableHandleShape shape)
+{
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+
+    RootedObject checkObj(cx, obj->staticPrototype());
+    if (!checkObj)
+        return false;
+
+    if (!LookupPropertyPure(cx, obj, id, holder.address(), shape.address()))
+        return false;
+
+    if (!holder)
+        return false;
+
+    return IsCacheableSetPropCallNative(checkObj, holder, shape) ||
+           IsCacheableSetPropCallPropertyOp(checkObj, holder, shape) ||
+           IsCacheableSetPropCallScripted(checkObj, holder, shape);
+}
+
+bool
+SetPropertyIC::attachDOMProxyUnshadowed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                        HandleObject obj, HandleId id, void* returnAddr)
+{
+    MOZ_ASSERT(IsCacheableDOMProxy(obj));
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    emitIdGuard(masm, id, &failures);
+
+    // Guard on the shape of the object.
+    masm.branchPtr(Assembler::NotEqual,
+                   Address(object(), ShapedObject::offsetOfShape()),
+                   ImmGCPtr(obj->maybeShape()), &failures);
+
+    // Guard that our expando object hasn't started shadowing this property.
+    CheckDOMProxyExpandoDoesNotShadow(cx, masm, obj, id, object(), &failures);
+
+    RootedObject holder(cx);
+    RootedShape shape(cx);
+    if (IsCacheableDOMProxyUnshadowedSetterCall(cx, obj, id, &holder, &shape)) {
+        if (!GenerateCallSetter(cx, ion, masm, attacher, obj, holder, shape, strict(),
+                                object(), temp(), value(), &failures, liveRegs_, returnAddr))
+        {
+            return false;
+        }
+    } else {
+        // Either there was no proto, or the property wasn't appropriately found on it.
+        // Drop back to just a call to Proxy::set().
+        if (!EmitCallProxySet(cx, masm, attacher, id, liveRegs_, object(),
+                            value(), returnAddr, strict()))
+        {
+            return false;
+        }
+    }
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "DOM proxy unshadowed set",
+                             JS::TrackedOutcome::ICSetPropStub_DOMProxyUnshadowed);
+}
+
+bool
+SetPropertyIC::attachCallSetter(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                HandleObject obj, HandleObject holder, HandleShape shape,
+                                void* returnAddr)
+{
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failure;
+    emitIdGuard(masm, shape->propid(), &failure);
+    TestMatchingReceiver(masm, attacher, object(), obj, &failure);
+
+    if (!GenerateCallSetter(cx, ion, masm, attacher, obj, holder, shape, strict(),
+                            object(), temp(), value(), &failure, liveRegs_, returnAddr))
+    {
+        return false;
+    }
+
+    // Rejoin jump.
+    attacher.jumpRejoin(masm);
+
+    // Jump to next stub.
+    masm.bind(&failure);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "setter call",
+                             JS::TrackedOutcome::ICSetPropStub_CallSetter);
+}
+
+static void
+GenerateAddSlot(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                JSObject* obj, Shape* oldShape, ObjectGroup* oldGroup,
+                Register object, Register tempReg, const ConstantOrRegister& value,
+                bool checkTypeset, Label* failures)
+{
+    // Use a modified version of TestMatchingReceiver that uses the old shape and group.
+    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)
+        CheckTypeSetForWrite(masm, obj, newShape->propid(), tempReg, value, failures);
+
+    // Guard shapes along prototype chain.
+    JSObject* proto = obj->staticPrototype();
+    Register protoReg = tempReg;
+    bool first = true;
+    while (proto) {
+        Shape* protoShape = proto->as<NativeObject>().lastProperty();
+
+        // Load next prototype.
+        masm.loadObjProto(first ? object : protoReg, protoReg);
+        first = false;
+
+        // Ensure that its shape matches.
+        masm.branchTestObjShape(Assembler::NotEqual, protoReg, protoShape, failures);
+
+        proto = proto->staticPrototype();
+    }
+
+    // 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();
+    if (NativeObject::dynamicSlotsCount(oldShape) != newNumDynamicSlots) {
+        AllocatableRegisterSet regs(RegisterSet::Volatile());
+        LiveRegisterSet save(regs.asLiveSet());
+        masm.PushRegsInMask(save);
+
+        // Get 2 temp registers, without clobbering the object register.
+        regs.takeUnchecked(object);
+        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);
+        masm.passABIArg(object);
+        masm.move32(Imm32(newNumDynamicSlots), temp2);
+        masm.passABIArg(temp2);
+        masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, NativeObject::growSlotsDontReportOOM));
+
+        // Branch on ReturnReg before restoring volatile registers, so
+        // ReturnReg isn't clobbered.
+        uint32_t framePushedAfterCall = masm.framePushed();
+        Label allocFailed, allocDone;
+        masm.branchIfFalseBool(ReturnReg, &allocFailed);
+        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())
+        masm.callPreBarrier(shapeAddr, MIRType::Shape);
+    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.
+        Label noTypeChange, skipPop;
+
+        masm.loadPtr(Address(object, JSObject::offsetOfGroup()), tempReg);
+        masm.branchPtr(Assembler::Equal,
+                       Address(tempReg, ObjectGroup::offsetOfAddendum()),
+                       ImmWord(0),
+                       &noTypeChange);
+
+        Address groupAddr(object, JSObject::offsetOfGroup());
+        if (cx->zone()->needsIncrementalBarrier())
+            masm.callPreBarrier(groupAddr, MIRType::ObjectGroup);
+        masm.storePtr(ImmGCPtr(obj->group()), groupAddr);
+
+        masm.bind(&noTypeChange);
+    }
+
+    // Set the value on the object. Since this is an add, obj->lastProperty()
+    // must be the shape of the property we are adding.
+    NativeObject::slotsSizeMustNotOverflow();
+    if (obj->as<NativeObject>().isFixedSlot(newShape->slot())) {
+        Address addr(object, NativeObject::getFixedSlotOffset(newShape->slot()));
+        masm.storeConstantOrRegister(value, addr);
+    } else {
+        masm.loadPtr(Address(object, NativeObject::offsetOfSlots()), tempReg);
+
+        Address addr(tempReg, obj->as<NativeObject>().dynamicSlotIndex(newShape->slot()) * sizeof(Value));
+        masm.storeConstantOrRegister(value, addr);
+    }
+
+    if (popObject)
+        masm.pop(object);
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Failure.
+    masm.bind(failures);
+
+    attacher.jumpNextStub(masm);
+}
+
+bool
+SetPropertyIC::attachAddSlot(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                             HandleObject obj, HandleId id, HandleShape oldShape,
+                             HandleObjectGroup oldGroup, bool checkTypeset)
+{
+    MOZ_ASSERT_IF(!needsTypeBarrier(), !checkTypeset);
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+
+    GenerateAddSlot(cx, masm, attacher, obj, oldShape, oldGroup, object(), temp(), value(),
+                    checkTypeset, &failures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "adding",
+                             JS::TrackedOutcome::ICSetPropStub_AddSlot);
+}
+
+static bool
+CanInlineSetPropTypeCheck(JSObject* obj, jsid id, const ConstantOrRegister& val,
+                          bool* checkTypeset)
+{
+    bool shouldCheck = false;
+    ObjectGroup* group = obj->group();
+    if (!group->unknownProperties()) {
+        HeapTypeSet* propTypes = group->maybeGetProperty(id);
+        if (!propTypes)
+            return false;
+        if (!propTypes->unknown()) {
+            if (obj->isSingleton() && !propTypes->nonConstantProperty())
+                return false;
+            shouldCheck = true;
+            if (val.constant()) {
+                // If the input is a constant, then don't bother if the barrier will always fail.
+                if (!propTypes->hasType(TypeSet::GetValueType(val.value())))
+                    return false;
+                shouldCheck = false;
+            } else {
+                TypedOrValueRegister reg = val.reg();
+                // We can do the same trick as above for primitive types of specialized registers.
+                // TIs handling of objects is complicated enough to warrant a runtime
+                // check, as we can't statically handle the case where the typeset
+                // contains the specific object, but doesn't have ANYOBJECT set.
+                if (reg.hasTyped() && reg.type() != MIRType::Object) {
+                    JSValueType valType = ValueTypeFromMIRType(reg.type());
+                    if (!propTypes->hasType(TypeSet::PrimitiveType(valType)))
+                        return false;
+                    shouldCheck = false;
+                }
+            }
+        }
+    }
+
+    *checkTypeset = shouldCheck;
+    return true;
+}
+
+static bool
+IsPropertySetInlineable(NativeObject* obj, HandleId id, MutableHandleShape pshape,
+                        const ConstantOrRegister& val, bool needsTypeBarrier, bool* checkTypeset)
+{
+    // CanInlineSetPropTypeCheck assumes obj has a non-lazy group.
+    MOZ_ASSERT(!obj->hasLazyGroup());
+
+    // Do a pure non-proto chain climbing lookup. See note in
+    // CanAttachNativeGetProp.
+    pshape.set(obj->lookupPure(id));
+
+    if (!pshape)
+        return false;
+
+    if (!pshape->hasSlot())
+        return false;
+
+    if (!pshape->hasDefaultSetter())
+        return false;
+
+    if (!pshape->writable())
+        return false;
+
+    *checkTypeset = false;
+    if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, id, val, checkTypeset))
+        return false;
+
+    return true;
+}
+
+static bool
+PrototypeChainShadowsPropertyAdd(JSContext* cx, JSObject* obj, jsid id)
+{
+    // Walk up the object prototype chain and ensure that all prototypes
+    // are native, and that all prototypes have no getter or setter
+    // defined on the property
+    for (JSObject* proto = obj->staticPrototype(); proto; proto = proto->staticPrototype()) {
+        // If prototype is non-native, don't optimize
+        if (!proto->isNative())
+            return true;
+
+        // If prototype defines this property in a non-plain way, don't optimize
+        Shape* protoShape = proto->as<NativeObject>().lookupPure(id);
+        if (protoShape && !protoShape->hasDefaultSetter())
+            return true;
+
+        // Otherwise, if there's no such property, watch out for a resolve
+        // hook that would need to be invoked and thus prevent inlining of
+        // property addition.
+        if (ClassMayResolveId(cx->names(), proto->getClass(), id, proto))
+             return true;
+    }
+
+    return false;
+}
+
+static bool
+IsPropertyAddInlineable(JSContext* cx, NativeObject* obj, HandleId id,
+                        const ConstantOrRegister& val,
+                        HandleShape oldShape, bool needsTypeBarrier, bool* checkTypeset)
+{
+    // If the shape of the object did not change, then this was not an add.
+    if (obj->lastProperty() == oldShape)
+        return false;
+
+    Shape* shape = obj->lookupPure(id);
+    if (!shape || shape->inDictionary() || !shape->hasSlot() || !shape->hasDefaultSetter())
+        return false;
+
+    // If we have a shape at this point and the object's shape changed, then
+    // the shape must be the one we just added.
+    MOZ_ASSERT(shape == obj->lastProperty());
+
+    // Watch out for resolve hooks.
+    if (ClassMayResolveId(cx->names(), obj->getClass(), id, obj))
+        return false;
+
+    // Likewise for an addProperty hook, since we'll need to invoke it.
+    if (obj->getClass()->getAddProperty())
+        return false;
+
+    if (!obj->nonProxyIsExtensible() || !shape->writable())
+        return false;
+
+    if (PrototypeChainShadowsPropertyAdd(cx, obj, id))
+        return false;
+
+    // Don't attach if we are adding a property to an object which the new
+    // script properties analysis hasn't been performed for yet, as there
+    // may be a group change required here afterwards.
+    if (obj->group()->newScript() && !obj->group()->newScript()->analyzed())
+        return false;
+
+    *checkTypeset = false;
+    if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, id, val, checkTypeset))
+        return false;
+
+    return true;
+}
+
+static SetPropertyIC::NativeSetPropCacheability
+CanAttachNativeSetProp(JSContext* cx, HandleObject obj, HandleId id, const ConstantOrRegister& val,
+                       bool needsTypeBarrier, MutableHandleObject holder,
+                       MutableHandleShape shape, bool* checkTypeset)
+{
+    // See if the property exists on the object.
+    if (obj->isNative() && IsPropertySetInlineable(&obj->as<NativeObject>(), id, shape, val,
+                                                   needsTypeBarrier, checkTypeset))
+    {
+        return SetPropertyIC::CanAttachSetSlot;
+    }
+
+    // If we couldn't find the property on the object itself, do a full, but
+    // still pure lookup for setters.
+    if (!LookupPropertyPure(cx, obj, id, holder.address(), shape.address()))
+        return SetPropertyIC::CanAttachNone;
+
+    // If the object doesn't have the property, we don't know if we can attach
+    // a stub to add the property until we do the VM call to add. If the
+    // property exists as a data property on the prototype, we should add
+    // a new, shadowing property.
+    if (obj->isNative() && (!shape || (obj != holder && holder->isNative() &&
+                                       shape->hasDefaultSetter() && shape->hasSlot())))
+    {
+        return SetPropertyIC::MaybeCanAttachAddSlot;
+    }
+
+    if (IsImplicitNonNativeProperty(shape))
+        return SetPropertyIC::CanAttachNone;
+
+    if (IsCacheableSetPropCallPropertyOp(obj, holder, shape) ||
+        IsCacheableSetPropCallNative(obj, holder, shape) ||
+        IsCacheableSetPropCallScripted(obj, holder, shape))
+    {
+        return SetPropertyIC::CanAttachCallSetter;
+    }
+
+    return SetPropertyIC::CanAttachNone;
+}
+
+static void
+GenerateSetUnboxed(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                   JSObject* obj, jsid id, uint32_t unboxedOffset, JSValueType unboxedType,
+                   Register object, Register tempReg, const ConstantOrRegister& value,
+                   bool checkTypeset, Label* failures)
+{
+    // Guard on the type of the object.
+    masm.branchPtr(Assembler::NotEqual,
+                   Address(object, JSObject::offsetOfGroup()),
+                   ImmGCPtr(obj->group()), failures);
+
+    if (checkTypeset)
+        CheckTypeSetForWrite(masm, obj, id, tempReg, value, failures);
+
+    Address address(object, UnboxedPlainObject::offsetOfData() + unboxedOffset);
+
+    if (cx->zone()->needsIncrementalBarrier()) {
+        if (unboxedType == JSVAL_TYPE_OBJECT)
+            masm.callPreBarrier(address, MIRType::Object);
+        else if (unboxedType == JSVAL_TYPE_STRING)
+            masm.callPreBarrier(address, MIRType::String);
+        else
+            MOZ_ASSERT(!UnboxedTypeNeedsPreBarrier(unboxedType));
+    }
+
+    masm.storeUnboxedProperty(address, unboxedType, value, failures);
+
+    attacher.jumpRejoin(masm);
+
+    masm.bind(failures);
+    attacher.jumpNextStub(masm);
+}
+
+static bool
+CanAttachSetUnboxed(JSContext* cx, HandleObject obj, HandleId id, const ConstantOrRegister& val,
+                    bool needsTypeBarrier, bool* checkTypeset,
+                    uint32_t* unboxedOffset, JSValueType* unboxedType)
+{
+    if (!obj->is<UnboxedPlainObject>())
+        return false;
+
+    const UnboxedLayout::Property* property = obj->as<UnboxedPlainObject>().layout().lookup(id);
+    if (property) {
+        *checkTypeset = false;
+        if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, id, val, checkTypeset))
+            return false;
+        *unboxedOffset = property->offset;
+        *unboxedType = property->type;
+        return true;
+    }
+
+    return false;
+}
+
+static bool
+CanAttachSetUnboxedExpando(JSContext* cx, HandleObject obj, HandleId id,
+                           const ConstantOrRegister& val,
+                           bool needsTypeBarrier, bool* checkTypeset, Shape** pshape)
+{
+    if (!obj->is<UnboxedPlainObject>())
+        return false;
+
+    Rooted<UnboxedExpandoObject*> expando(cx, obj->as<UnboxedPlainObject>().maybeExpando());
+    if (!expando)
+        return false;
+
+    Shape* shape = expando->lookupPure(id);
+    if (!shape || !shape->hasDefaultSetter() || !shape->hasSlot() || !shape->writable())
+        return false;
+
+    *checkTypeset = false;
+    if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, id, val, checkTypeset))
+        return false;
+
+    *pshape = shape;
+    return true;
+}
+
+static bool
+CanAttachAddUnboxedExpando(JSContext* cx, HandleObject obj, HandleShape oldShape,
+                           HandleId id, const ConstantOrRegister& val,
+                           bool needsTypeBarrier, bool* checkTypeset)
+{
+    if (!obj->is<UnboxedPlainObject>())
+        return false;
+
+    Rooted<UnboxedExpandoObject*> expando(cx, obj->as<UnboxedPlainObject>().maybeExpando());
+    if (!expando || expando->inDictionaryMode())
+        return false;
+
+    Shape* newShape = expando->lastProperty();
+    if (newShape->isEmptyShape() || newShape->propid() != id || newShape->previous() != oldShape)
+        return false;
+
+    MOZ_ASSERT(newShape->hasDefaultSetter() && newShape->hasSlot() && newShape->writable());
+
+    if (PrototypeChainShadowsPropertyAdd(cx, obj, id))
+        return false;
+
+    *checkTypeset = false;
+    if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, id, val, checkTypeset))
+        return false;
+
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachUnboxed(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                HandleObject obj, HandleId id, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+
+    bool checkTypeset = false;
+    uint32_t unboxedOffset;
+    JSValueType unboxedType;
+    if (!CanAttachSetUnboxed(cx, obj, id, value(), needsTypeBarrier(), &checkTypeset,
+                             &unboxedOffset, &unboxedType))
+    {
+        return true;
+    }
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    emitIdGuard(masm, id, &failures);
+
+    GenerateSetUnboxed(cx, masm, attacher, obj, id, unboxedOffset, unboxedType,
+                       object(), temp(), value(), checkTypeset, &failures);
+    return linkAndAttachStub(cx, masm, attacher, ion, "set_unboxed",
+                             JS::TrackedOutcome::ICSetPropStub_SetUnboxed);
+}
+
+bool
+SetPropertyIC::tryAttachProxy(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                              HandleObject obj, HandleId id, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+
+    if (!obj->is<ProxyObject>())
+        return true;
+
+    void* returnAddr = GetReturnAddressToIonCode(cx);
+    if (IsCacheableDOMProxy(obj)) {
+        DOMProxyShadowsResult shadows = GetDOMProxyShadowsCheck()(cx, obj, id);
+        if (shadows == ShadowCheckFailed)
+            return false;
+
+        if (DOMProxyIsShadowing(shadows)) {
+            if (!attachDOMProxyShadowed(cx, outerScript, ion, obj, id, returnAddr))
+                return false;
+            *emitted = true;
+            return true;
+        }
+
+        MOZ_ASSERT(shadows == DoesntShadow || shadows == DoesntShadowUnique);
+        if (shadows == DoesntShadowUnique)
+            reset(Reprotect);
+        if (!attachDOMProxyUnshadowed(cx, outerScript, ion, obj, id, returnAddr))
+            return false;
+        *emitted = true;
+        return true;
+    }
+
+    if (hasGenericProxyStub())
+        return true;
+
+    if (!attachGenericProxy(cx, outerScript, ion, id, returnAddr))
+        return false;
+    *emitted = true;
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachNative(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                               HandleObject obj, HandleId id, bool* emitted, bool* tryNativeAddSlot)
+{
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(!*tryNativeAddSlot);
+
+    RootedShape shape(cx);
+    RootedObject holder(cx);
+    bool checkTypeset = false;
+    NativeSetPropCacheability canCache = CanAttachNativeSetProp(cx, obj, id, value(), needsTypeBarrier(),
+                                                                &holder, &shape, &checkTypeset);
+    switch (canCache) {
+      case CanAttachNone:
+        return true;
+
+      case CanAttachSetSlot: {
+        RootedNativeObject nobj(cx, &obj->as<NativeObject>());
+        if (!attachSetSlot(cx, outerScript, ion, nobj, shape, checkTypeset))
+            return false;
+        *emitted = true;
+        return true;
+      }
+
+      case CanAttachCallSetter: {
+        void* returnAddr = GetReturnAddressToIonCode(cx);
+        if (!attachCallSetter(cx, outerScript, ion, obj, holder, shape, returnAddr))
+            return false;
+        *emitted = true;
+        return true;
+      }
+
+      case MaybeCanAttachAddSlot:
+        *tryNativeAddSlot = true;
+        return true;
+    }
+
+    MOZ_CRASH("Unreachable");
+}
+
+bool
+SetPropertyIC::tryAttachUnboxedExpando(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                       HandleObject obj, HandleId id, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+
+    RootedShape shape(cx);
+    bool checkTypeset = false;
+    if (!CanAttachSetUnboxedExpando(cx, obj, id, value(), needsTypeBarrier(),
+                                    &checkTypeset, shape.address()))
+    {
+        return true;
+    }
+
+    if (!attachSetSlot(cx, outerScript, ion, obj, shape, checkTypeset))
+        return false;
+    *emitted = true;
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachStub(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                             HandleObject obj, HandleValue idval, HandleValue value,
+                             MutableHandleId id, bool* emitted, bool* tryNativeAddSlot)
+{
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(!*tryNativeAddSlot);
+
+    if (!canAttachStub())
+        return true;
+
+    // Fail cache emission if the object is frozen
+    if (obj->is<NativeObject>() && obj->as<NativeObject>().getElementsHeader()->isFrozen())
+        return true;
+
+    bool nameOrSymbol;
+    if (!ValueToNameOrSymbolId(cx, idval, id, &nameOrSymbol))
+        return false;
+
+    if (nameOrSymbol) {
+        if (!*emitted && !tryAttachProxy(cx, outerScript, ion, obj, id, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachNative(cx, outerScript, ion, obj, id, emitted, tryNativeAddSlot))
+            return false;
+
+        if (!*emitted && !tryAttachUnboxed(cx, outerScript, ion, obj, id, emitted))
+            return false;
+
+        if (!*emitted && !tryAttachUnboxedExpando(cx, outerScript, ion, obj, id, emitted))
+            return false;
+    }
+
+    if (idval.isInt32()) {
+        if (!*emitted && !tryAttachDenseElement(cx, outerScript, ion, obj, idval, emitted))
+            return false;
+        if (!*emitted &&
+            !tryAttachTypedArrayElement(cx, outerScript, ion, obj, idval, value, emitted))
+        {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachAddSlot(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                HandleObject obj, HandleId id, HandleObjectGroup oldGroup,
+                                HandleShape oldShape, bool tryNativeAddSlot, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+
+    if (!canAttachStub())
+        return true;
+
+    if (!JSID_IS_STRING(id) && !JSID_IS_SYMBOL(id))
+        return true;
+
+    // Fail cache emission if the object is frozen
+    if (obj->is<NativeObject>() && obj->as<NativeObject>().getElementsHeader()->isFrozen())
+        return true;
+
+    // A GC may have caused cache.value() to become stale as it is not traced.
+    // In this case the IonScript will have been invalidated, so check for that.
+    // Assert no further GC is possible past this point.
+    JS::AutoAssertNoGC nogc;
+    if (ion->invalidated())
+        return true;
+
+    // The property did not exist before, now we can try to inline the property add.
+    bool checkTypeset = false;
+    if (tryNativeAddSlot &&
+        IsPropertyAddInlineable(cx, &obj->as<NativeObject>(), id, value(), oldShape,
+                                needsTypeBarrier(), &checkTypeset))
+    {
+        if (!attachAddSlot(cx, outerScript, ion, obj, id, oldShape, oldGroup, checkTypeset))
+            return false;
+        *emitted = true;
+        return true;
+    }
+
+    checkTypeset = false;
+    if (CanAttachAddUnboxedExpando(cx, obj, oldShape, id, value(), needsTypeBarrier(),
+                                   &checkTypeset))
+    {
+        if (!attachAddSlot(cx, outerScript, ion, obj, id, oldShape, oldGroup, checkTypeset))
+            return false;
+        *emitted = true;
+        return true;
+    }
+
+    return true;
+}
+
+bool
+SetPropertyIC::update(JSContext* cx, HandleScript outerScript, size_t cacheIndex, HandleObject obj,
+                      HandleValue idval, HandleValue value)
+{
+    IonScript* ion = outerScript->ionScript();
+    SetPropertyIC& cache = ion->getCache(cacheIndex).toSetProperty();
+
+    // Remember the old group and shape if we may attach an add-property stub.
+    // Also, some code under tryAttachStub depends on obj having a non-lazy
+    // group, see for instance CanInlineSetPropTypeCheck.
+    RootedObjectGroup oldGroup(cx);
+    RootedShape oldShape(cx);
+    if (cache.canAttachStub()) {
+        oldGroup = JSObject::getGroup(cx, obj);
+        if (!oldGroup)
+            return false;
+
+        oldShape = obj->maybeShape();
+        if (obj->is<UnboxedPlainObject>()) {
+            MOZ_ASSERT(!oldShape);
+            if (UnboxedExpandoObject* expando = obj->as<UnboxedPlainObject>().maybeExpando())
+                oldShape = expando->lastProperty();
+        }
+    }
+
+    RootedId id(cx);
+    bool emitted = false;
+    bool tryNativeAddSlot = false;
+    if (!cache.tryAttachStub(cx, outerScript, ion, obj, idval, value, &id, &emitted,
+                             &tryNativeAddSlot))
+    {
+        return false;
+    }
+
+    // Set/Add the property on the object, the inlined cache are setup for the next execution.
+    if (JSOp(*cache.pc()) == JSOP_INITGLEXICAL) {
+        RootedScript script(cx);
+        jsbytecode* pc;
+        cache.getScriptedLocation(&script, &pc);
+        MOZ_ASSERT(!script->hasNonSyntacticScope());
+        InitGlobalLexicalOperation(cx, &cx->global()->lexicalEnvironment(), script, pc, value);
+    } else if (*cache.pc() == JSOP_SETELEM || *cache.pc() == JSOP_STRICTSETELEM) {
+        if (!SetObjectElement(cx, obj, idval, value, cache.strict()))
+            return false;
+    } else {
+        RootedPropertyName name(cx, idval.toString()->asAtom().asPropertyName());
+        if (!SetProperty(cx, obj, name, value, cache.strict(), cache.pc()))
+            return false;
+    }
+
+    if (!emitted &&
+        !cache.tryAttachAddSlot(cx, outerScript, ion, obj, id, oldGroup, oldShape,
+                                tryNativeAddSlot, &emitted))
+    {
+        return false;
+    }
+
+    if (!emitted)
+        JitSpew(JitSpew_IonIC, "Failed to attach SETPROP cache");
+
+    return true;
+}
+
+void
+SetPropertyIC::reset(ReprotectCode reprotect)
+{
+    IonCache::reset(reprotect);
+    hasGenericProxyStub_ = false;
+    hasDenseStub_ = false;
+}
+
+static bool
+GenerateDenseElement(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                     JSObject* obj, const Value& idval, Register object,
+                     TypedOrValueRegister index, TypedOrValueRegister output)
+{
+    Label failures;
+
+    // Guard object's shape.
+    RootedShape shape(cx, obj->as<NativeObject>().lastProperty());
+    if (!shape)
+        return false;
+    masm.branchTestObjShape(Assembler::NotEqual, object, shape, &failures);
+
+    // Ensure the index is an int32 value.
+    Register indexReg = InvalidReg;
+
+    if (index.hasValue()) {
+        indexReg = output.scratchReg().gpr();
+        MOZ_ASSERT(indexReg != InvalidReg);
+        ValueOperand val = index.valueReg();
+
+        masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+
+        // Unbox the index.
+        masm.unboxInt32(val, indexReg);
+    } else {
+        MOZ_ASSERT(!index.typedReg().isFloat());
+        indexReg = index.typedReg().gpr();
+    }
+
+    // Load elements vector.
+    masm.push(object);
+    masm.loadPtr(Address(object, NativeObject::offsetOfElements()), object);
+
+    Label hole;
+
+    // Guard on the initialized length.
+    Address initLength(object, ObjectElements::offsetOfInitializedLength());
+    masm.branch32(Assembler::BelowOrEqual, initLength, indexReg, &hole);
+
+    // Check for holes & load the value.
+    masm.loadElementTypedOrValue(BaseObjectElementIndex(object, indexReg),
+                                 output, true, &hole);
+
+    masm.pop(object);
+    attacher.jumpRejoin(masm);
+
+    // All failures flow to here.
+    masm.bind(&hole);
+    masm.pop(object);
+    masm.bind(&failures);
+
+    attacher.jumpNextStub(masm);
+
+    return true;
+}
+
+bool
+GetPropertyIC::tryAttachDenseElement(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                     HandleObject obj, HandleValue idval, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (hasDenseStub())
+        return true;
+
+    if (!obj->isNative() || !idval.isInt32())
+        return true;
+
+    if (uint32_t(idval.toInt32()) >= obj->as<NativeObject>().getDenseInitializedLength())
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+    if (!GenerateDenseElement(cx, masm, attacher, obj, idval, object(), id().reg(), output()))
+        return false;
+
+    setHasDenseStub();
+    return linkAndAttachStub(cx, masm, attacher, ion, "dense array",
+                             JS::TrackedOutcome::ICGetElemStub_Dense);
+}
+
+
+/* static */ bool
+GetPropertyIC::canAttachDenseElementHole(JSObject* obj, HandleValue idval, TypedOrValueRegister output)
+{
+
+    if (!idval.isInt32() || idval.toInt32() < 0)
+        return false;
+
+    if (!output.hasValue())
+        return false;
+
+    if (!obj->isNative())
+        return false;
+
+    if (obj->as<NativeObject>().getDenseInitializedLength() == 0)
+        return false;
+
+    do {
+        if (obj->isIndexed())
+            return false;
+
+        if (ClassCanHaveExtraProperties(obj->getClass()))
+            return false;
+
+        JSObject* proto = obj->staticPrototype();
+        if (!proto)
+            break;
+
+        if (!proto->isNative())
+            return false;
+
+        // Make sure objects on the prototype don't have dense elements.
+        if (proto->as<NativeObject>().getDenseInitializedLength() != 0)
+            return false;
+
+        obj = proto;
+    } while (obj);
+
+    return true;
+}
+
+static bool
+GenerateDenseElementHole(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                         IonScript* ion, JSObject* obj, HandleValue idval,
+                         Register object, TypedOrValueRegister index, TypedOrValueRegister output)
+{
+    MOZ_ASSERT(GetPropertyIC::canAttachDenseElementHole(obj, idval, output));
+
+    Register scratchReg = output.valueReg().scratchReg();
+
+    // Guard on the shape and group, to prevent non-dense elements from appearing.
+    Label failures;
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                   Address(object, ShapedObject::offsetOfShape()),
+                                   ImmGCPtr(obj->as<NativeObject>().lastProperty()), &failures);
+
+
+    if (obj->hasUncacheableProto()) {
+        masm.loadPtr(Address(object, JSObject::offsetOfGroup()), scratchReg);
+        Address proto(scratchReg, ObjectGroup::offsetOfProto());
+        masm.branchPtr(Assembler::NotEqual, proto, ImmGCPtr(obj->staticPrototype()), &failures);
+    }
+
+    JSObject* pobj = obj->staticPrototype();
+    while (pobj) {
+        MOZ_ASSERT(pobj->as<NativeObject>().lastProperty());
+
+        masm.movePtr(ImmGCPtr(pobj), scratchReg);
+
+        // Non-singletons with uncacheable protos can change their proto
+        // without a shape change, so also guard on the group (which determines
+        // the proto) in this case.
+        if (pobj->hasUncacheableProto() && !pobj->isSingleton()) {
+            Address groupAddr(scratchReg, JSObject::offsetOfGroup());
+            masm.branchPtr(Assembler::NotEqual, groupAddr, ImmGCPtr(pobj->group()), &failures);
+        }
+
+        // Make sure the shape matches, to avoid non-dense elements.
+        masm.branchPtr(Assembler::NotEqual, Address(scratchReg, ShapedObject::offsetOfShape()),
+                       ImmGCPtr(pobj->as<NativeObject>().lastProperty()), &failures);
+
+        // Load elements vector.
+        masm.loadPtr(Address(scratchReg, NativeObject::offsetOfElements()), scratchReg);
+
+        // Also make sure there are no dense elements.
+        Label hole;
+        Address initLength(scratchReg, ObjectElements::offsetOfInitializedLength());
+        masm.branch32(Assembler::NotEqual, initLength, Imm32(0), &failures);
+
+        pobj = pobj->staticPrototype();
+    }
+
+    // Ensure the index is an int32 value.
+    Register indexReg;
+    if (index.hasValue()) {
+        // Unbox the index.
+        ValueOperand val = index.valueReg();
+        masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+        indexReg = scratchReg;
+        masm.unboxInt32(val, indexReg);
+    } else {
+        MOZ_ASSERT(index.type() == MIRType::Int32);
+        indexReg = index.typedReg().gpr();
+    }
+
+    // Make sure index is nonnegative.
+    masm.branch32(Assembler::LessThan, indexReg, Imm32(0), &failures);
+
+    // Save the object register.
+    Register elementsReg = object;
+    masm.push(object);
+
+    // Load elements vector.
+    masm.loadPtr(Address(object, NativeObject::offsetOfElements()), elementsReg);
+
+    // Guard on the initialized length.
+    Label hole;
+    Address initLength(elementsReg, ObjectElements::offsetOfInitializedLength());
+    masm.branch32(Assembler::BelowOrEqual, initLength, indexReg, &hole);
+
+    // Load the value.
+    Label done;
+    masm.loadValue(BaseObjectElementIndex(elementsReg, indexReg), output.valueReg());
+    masm.branchTestMagic(Assembler::NotEqual, output.valueReg(), &done);
+
+    // Load undefined for the hole.
+    masm.bind(&hole);
+    masm.moveValue(UndefinedValue(), output.valueReg());
+
+    masm.bind(&done);
+    // Restore the object register.
+    if (elementsReg == object)
+        masm.pop(object);
+    attacher.jumpRejoin(masm);
+
+    // All failure flows through here.
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return true;
+}
+
+bool
+GetPropertyIC::tryAttachDenseElementHole(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                         HandleObject obj, HandleValue idval, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!monitoredResult())
+        return true;
+
+    if (!canAttachDenseElementHole(obj, idval, output()))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+    GenerateDenseElementHole(cx, masm, attacher, ion, obj, idval, object(), id().reg(), output());
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "dense hole",
+                             JS::TrackedOutcome::ICGetElemStub_DenseHole);
+}
+
+/* static */ bool
+GetPropertyIC::canAttachTypedOrUnboxedArrayElement(JSObject* obj, const Value& idval,
+                                                   TypedOrValueRegister output)
+{
+    if (!obj->is<TypedArrayObject>() && !obj->is<UnboxedArrayObject>())
+        return false;
+
+    MOZ_ASSERT(idval.isInt32() || idval.isString());
+
+    // Don't emit a stub if the access is out of bounds. We make to make
+    // certain that we monitor the type coming out of the typed array when
+    // we generate the stub. Out of bounds accesses will hit the fallback
+    // path.
+    uint32_t index;
+    if (idval.isInt32()) {
+        index = idval.toInt32();
+    } else {
+        index = GetIndexFromString(idval.toString());
+        if (index == UINT32_MAX)
+            return false;
+    }
+
+    if (obj->is<TypedArrayObject>()) {
+        if (index >= obj->as<TypedArrayObject>().length())
+            return false;
+
+        // The output register is not yet specialized as a float register, the only
+        // way to accept float typed arrays for now is to return a Value type.
+        uint32_t arrayType = obj->as<TypedArrayObject>().type();
+        if (arrayType == Scalar::Float32 || arrayType == Scalar::Float64)
+            return output.hasValue();
+
+        return output.hasValue() || !output.typedReg().isFloat();
+    }
+
+    if (index >= obj->as<UnboxedArrayObject>().initializedLength())
+        return false;
+
+    JSValueType elementType = obj->as<UnboxedArrayObject>().elementType();
+    if (elementType == JSVAL_TYPE_DOUBLE)
+        return output.hasValue();
+
+    return output.hasValue() || !output.typedReg().isFloat();
+}
+
+static void
+GenerateGetTypedOrUnboxedArrayElement(JSContext* cx, MacroAssembler& masm,
+                                      IonCache::StubAttacher& attacher,
+                                      HandleObject array, const Value& idval, Register object,
+                                      const ConstantOrRegister& index, TypedOrValueRegister output,
+                                      bool allowDoubleResult)
+{
+    MOZ_ASSERT(GetPropertyIC::canAttachTypedOrUnboxedArrayElement(array, idval, output));
+
+    Label failures;
+
+    TestMatchingReceiver(masm, attacher, object, array, &failures);
+
+    // Decide to what type index the stub should be optimized
+    Register tmpReg = output.scratchReg().gpr();
+    MOZ_ASSERT(tmpReg != InvalidReg);
+    Register indexReg = tmpReg;
+    if (idval.isString()) {
+        MOZ_ASSERT(GetIndexFromString(idval.toString()) != UINT32_MAX);
+
+        if (index.constant()) {
+            MOZ_ASSERT(idval == index.value());
+            masm.move32(Imm32(GetIndexFromString(idval.toString())), indexReg);
+        } else {
+            // Part 1: Get the string into a register
+            Register str;
+            if (index.reg().hasValue()) {
+                ValueOperand val = index.reg().valueReg();
+                masm.branchTestString(Assembler::NotEqual, val, &failures);
+
+                str = masm.extractString(val, indexReg);
+            } else {
+                MOZ_ASSERT(!index.reg().typedReg().isFloat());
+                str = index.reg().typedReg().gpr();
+            }
+
+            // Part 2: Call to translate the str into index
+            AllocatableRegisterSet regs(RegisterSet::Volatile());
+            LiveRegisterSet save(regs.asLiveSet());
+            masm.PushRegsInMask(save);
+            regs.takeUnchecked(str);
+
+            Register temp = regs.takeAnyGeneral();
+
+            masm.setupUnalignedABICall(temp);
+            masm.passABIArg(str);
+            masm.callWithABI(JS_FUNC_TO_DATA_PTR(void*, GetIndexFromString));
+            masm.mov(ReturnReg, indexReg);
+
+            LiveRegisterSet ignore;
+            ignore.add(indexReg);
+            masm.PopRegsInMaskIgnore(save, ignore);
+
+            masm.branch32(Assembler::Equal, indexReg, Imm32(UINT32_MAX), &failures);
+        }
+    } else {
+        MOZ_ASSERT(idval.isInt32());
+        MOZ_ASSERT(!index.constant());
+
+        if (index.reg().hasValue()) {
+            ValueOperand val = index.reg().valueReg();
+            masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+
+            // Unbox the index.
+            masm.unboxInt32(val, indexReg);
+        } else {
+            MOZ_ASSERT(!index.reg().typedReg().isFloat());
+            indexReg = index.reg().typedReg().gpr();
+        }
+    }
+
+    Label popObjectAndFail;
+
+    if (array->is<TypedArrayObject>()) {
+        // Guard on the initialized length.
+        Address length(object, TypedArrayObject::lengthOffset());
+        masm.branch32(Assembler::BelowOrEqual, length, indexReg, &failures);
+
+        // Save the object register on the stack in case of failure.
+        Register elementReg = object;
+        masm.push(object);
+
+        // Load elements vector.
+        masm.loadPtr(Address(object, TypedArrayObject::dataOffset()), elementReg);
+
+        // Load the value. We use an invalid register because the destination
+        // register is necessary a non double register.
+        Scalar::Type arrayType = array->as<TypedArrayObject>().type();
+        int width = Scalar::byteSize(arrayType);
+        BaseIndex source(elementReg, indexReg, ScaleFromElemWidth(width));
+        if (output.hasValue()) {
+            masm.loadFromTypedArray(arrayType, source, output.valueReg(), allowDoubleResult,
+                                    elementReg, &popObjectAndFail);
+        } else {
+            masm.loadFromTypedArray(arrayType, source, output.typedReg(), elementReg, &popObjectAndFail);
+        }
+    } else {
+        // Save the object register on the stack in case of failure.
+        masm.push(object);
+
+        // Guard on the initialized length.
+        masm.load32(Address(object, UnboxedArrayObject::offsetOfCapacityIndexAndInitializedLength()), object);
+        masm.and32(Imm32(UnboxedArrayObject::InitializedLengthMask), object);
+        masm.branch32(Assembler::BelowOrEqual, object, indexReg, &popObjectAndFail);
+
+        // Load elements vector.
+        Register elementReg = object;
+        masm.loadPtr(Address(masm.getStackPointer(), 0), object);
+        masm.loadPtr(Address(object, UnboxedArrayObject::offsetOfElements()), elementReg);
+
+        JSValueType elementType = array->as<UnboxedArrayObject>().elementType();
+        BaseIndex source(elementReg, indexReg, ScaleFromElemWidth(UnboxedTypeSize(elementType)));
+        masm.loadUnboxedProperty(source, elementType, output);
+    }
+
+    masm.pop(object);
+    attacher.jumpRejoin(masm);
+
+    // Restore the object before continuing to the next stub.
+    masm.bind(&popObjectAndFail);
+    masm.pop(object);
+    masm.bind(&failures);
+
+    attacher.jumpNextStub(masm);
+}
+
+bool
+GetPropertyIC::tryAttachTypedOrUnboxedArrayElement(JSContext* cx, HandleScript outerScript,
+                                                   IonScript* ion, HandleObject obj,
+                                                   HandleValue idval, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!canAttachTypedOrUnboxedArrayElement(obj, idval, output()))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+    GenerateGetTypedOrUnboxedArrayElement(cx, masm, attacher, obj, idval, object(), id(),
+                                          output(), allowDoubleResult_);
+    return linkAndAttachStub(cx, masm, attacher, ion, "typed array",
+                             JS::TrackedOutcome::ICGetElemStub_TypedArray);
+}
+
+bool
+GetPropertyIC::tryAttachArgumentsElement(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                         HandleObject obj, HandleValue idval, bool* emitted)
+{
+    MOZ_ASSERT(canAttachStub());
+    MOZ_ASSERT(!*emitted);
+
+    if (!IsOptimizableArgumentsObjectForGetElem(obj, idval))
+        return true;
+
+    MOZ_ASSERT(obj->is<ArgumentsObject>());
+
+    if (hasArgumentsElementStub(obj->is<MappedArgumentsObject>()))
+        return true;
+
+    TypedOrValueRegister index = id().reg();
+    if (index.type() != MIRType::Value && index.type() != MIRType::Int32)
+        return true;
+
+    MOZ_ASSERT(output().hasValue());
+
+    *emitted = true;
+
+    Label failures;
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Register tmpReg = output().scratchReg().gpr();
+    MOZ_ASSERT(tmpReg != InvalidReg);
+
+    masm.branchTestObjClass(Assembler::NotEqual, object(), tmpReg, obj->getClass(), &failures);
+
+    // Get initial ArgsObj length value, test if length or any element have
+    // been overridden.
+    masm.unboxInt32(Address(object(), ArgumentsObject::getInitialLengthSlotOffset()), tmpReg);
+    masm.branchTest32(Assembler::NonZero, tmpReg,
+                      Imm32(ArgumentsObject::LENGTH_OVERRIDDEN_BIT |
+                            ArgumentsObject::ELEMENT_OVERRIDDEN_BIT),
+                      &failures);
+    masm.rshiftPtr(Imm32(ArgumentsObject::PACKED_BITS_COUNT), tmpReg);
+
+    // Decide to what type index the stub should be optimized
+    Register indexReg;
+
+    // Check index against length.
+    Label failureRestoreIndex;
+    if (index.hasValue()) {
+        ValueOperand val = index.valueReg();
+        masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+        indexReg = val.scratchReg();
+
+        masm.unboxInt32(val, indexReg);
+        masm.branch32(Assembler::AboveOrEqual, indexReg, tmpReg, &failureRestoreIndex);
+    } else {
+        MOZ_ASSERT(index.type() == MIRType::Int32);
+        indexReg = index.typedReg().gpr();
+        masm.branch32(Assembler::AboveOrEqual, indexReg, tmpReg, &failures);
+    }
+
+    // Fail if we have a RareArgumentsData (elements were deleted).
+    masm.loadPrivate(Address(object(), ArgumentsObject::getDataSlotOffset()), tmpReg);
+    masm.branchPtr(Assembler::NotEqual,
+                   Address(tmpReg, offsetof(ArgumentsData, rareData)),
+                   ImmWord(0),
+                   &failureRestoreIndex);
+
+    // Get the address to load from into tmpReg
+    masm.loadPrivate(Address(object(), ArgumentsObject::getDataSlotOffset()), tmpReg);
+    masm.addPtr(Imm32(ArgumentsData::offsetOfArgs()), tmpReg);
+
+    BaseValueIndex elemIdx(tmpReg, indexReg);
+
+    // Ensure result is not magic value, and type-check result.
+    masm.branchTestMagic(Assembler::Equal, elemIdx, &failureRestoreIndex);
+
+    masm.loadTypedOrValue(elemIdx, output());
+
+    // indexReg may need to be reconstructed if it was originally a value.
+    if (index.hasValue())
+        masm.tagValue(JSVAL_TYPE_INT32, indexReg, index.valueReg());
+
+    // Success.
+    attacher.jumpRejoin(masm);
+
+    // Restore the object before continuing to the next stub.
+    masm.pop(indexReg);
+    masm.bind(&failureRestoreIndex);
+    if (index.hasValue())
+        masm.tagValue(JSVAL_TYPE_INT32, indexReg, index.valueReg());
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    if (obj->is<UnmappedArgumentsObject>()) {
+        MOZ_ASSERT(!hasUnmappedArgumentsElementStub_);
+        hasUnmappedArgumentsElementStub_ = true;
+        return linkAndAttachStub(cx, masm, attacher, ion, "ArgsObj element (unmapped)",
+                                 JS::TrackedOutcome::ICGetElemStub_ArgsElementUnmapped);
+    }
+
+    MOZ_ASSERT(!hasMappedArgumentsElementStub_);
+    hasMappedArgumentsElementStub_ = true;
+    return linkAndAttachStub(cx, masm, attacher, ion, "ArgsObj element (mapped)",
+                             JS::TrackedOutcome::ICGetElemStub_ArgsElementMapped);
+}
+
+static bool
+IsDenseElementSetInlineable(JSObject* obj, const Value& idval, const ConstantOrRegister& val,
+                            bool needsTypeBarrier, bool* checkTypeset)
+{
+    if (!obj->is<ArrayObject>())
+        return false;
+
+    if (!idval.isInt32())
+        return false;
+
+    // The object may have a setter definition,
+    // either directly, or via a prototype, or via the target object for a prototype
+    // which is a proxy, that handles a particular integer write.
+    // Scan the prototype and shape chain to make sure that this is not the case.
+    JSObject* curObj = obj;
+    while (curObj) {
+        // Ensure object is native.  (This guarantees static prototype below.)
+        if (!curObj->isNative())
+            return false;
+
+        // Ensure all indexed properties are stored in dense elements.
+        if (curObj->isIndexed())
+            return false;
+
+        curObj = curObj->staticPrototype();
+    }
+
+    *checkTypeset = false;
+    if (needsTypeBarrier && !CanInlineSetPropTypeCheck(obj, JSID_VOID, val, checkTypeset))
+        return false;
+
+    return true;
+}
+
+static bool
+IsTypedArrayElementSetInlineable(JSObject* obj, const Value& idval, const Value& value)
+{
+    // Don't bother attaching stubs for assigning strings, objects or symbols.
+    return obj->is<TypedArrayObject>() && idval.isInt32() &&
+           !value.isString() && !value.isObject() && !value.isSymbol();
+}
+
+static void
+StoreDenseElement(MacroAssembler& masm, const ConstantOrRegister& value, Register elements,
+                  BaseObjectElementIndex target)
+{
+    // If the ObjectElements::CONVERT_DOUBLE_ELEMENTS flag is set, int32 values
+    // have to be converted to double first. If the value is not int32, it can
+    // always be stored directly.
+
+    Address elementsFlags(elements, ObjectElements::offsetOfFlags());
+    if (value.constant()) {
+        Value v = value.value();
+        Label done;
+        if (v.isInt32()) {
+            Label dontConvert;
+            masm.branchTest32(Assembler::Zero, elementsFlags,
+                              Imm32(ObjectElements::CONVERT_DOUBLE_ELEMENTS),
+                              &dontConvert);
+            masm.storeValue(DoubleValue(v.toInt32()), target);
+            masm.jump(&done);
+            masm.bind(&dontConvert);
+        }
+        masm.storeValue(v, target);
+        masm.bind(&done);
+        return;
+    }
+
+    TypedOrValueRegister reg = value.reg();
+    if (reg.hasTyped() && reg.type() != MIRType::Int32) {
+        masm.storeTypedOrValue(reg, target);
+        return;
+    }
+
+    Label convert, storeValue, done;
+    masm.branchTest32(Assembler::NonZero, elementsFlags,
+                      Imm32(ObjectElements::CONVERT_DOUBLE_ELEMENTS),
+                      &convert);
+    masm.bind(&storeValue);
+    masm.storeTypedOrValue(reg, target);
+    masm.jump(&done);
+
+    masm.bind(&convert);
+    if (reg.hasValue()) {
+        masm.branchTestInt32(Assembler::NotEqual, reg.valueReg(), &storeValue);
+        masm.int32ValueToDouble(reg.valueReg(), ScratchDoubleReg);
+        masm.storeDouble(ScratchDoubleReg, target);
+    } else {
+        MOZ_ASSERT(reg.type() == MIRType::Int32);
+        masm.convertInt32ToDouble(reg.typedReg().gpr(), ScratchDoubleReg);
+        masm.storeDouble(ScratchDoubleReg, target);
+    }
+
+    masm.bind(&done);
+}
+
+static bool
+GenerateSetDenseElement(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                        JSObject* obj, const Value& idval, bool guardHoles, Register object,
+                        TypedOrValueRegister index, const ConstantOrRegister& value,
+                        Register tempToUnboxIndex, Register temp,
+                        bool needsTypeBarrier, bool checkTypeset)
+{
+    MOZ_ASSERT(obj->isNative());
+    MOZ_ASSERT(idval.isInt32());
+
+    Label failures;
+
+    // Guard object is a dense array.
+    Shape* shape = obj->as<NativeObject>().lastProperty();
+    if (!shape)
+        return false;
+    masm.branchTestObjShape(Assembler::NotEqual, object, shape, &failures);
+
+    // Guard that the incoming value is in the type set for the property
+    // if a type barrier is required.
+    if (needsTypeBarrier) {
+        masm.branchTestObjGroup(Assembler::NotEqual, object, obj->group(), &failures);
+        if (checkTypeset)
+            CheckTypeSetForWrite(masm, obj, JSID_VOID, temp, value, &failures);
+    }
+
+    // Ensure the index is an int32 value.
+    Register indexReg;
+    if (index.hasValue()) {
+        ValueOperand val = index.valueReg();
+        masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+
+        indexReg = masm.extractInt32(val, tempToUnboxIndex);
+    } else {
+        MOZ_ASSERT(!index.typedReg().isFloat());
+        indexReg = index.typedReg().gpr();
+    }
+
+    {
+        // Load obj->elements.
+        Register elements = temp;
+        masm.loadPtr(Address(object, NativeObject::offsetOfElements()), elements);
+
+        // Compute the location of the element.
+        BaseObjectElementIndex target(elements, indexReg);
+
+        Label storeElement;
+
+        // If TI cannot help us deal with HOLES by preventing indexed properties
+        // on the prototype chain, we have to be very careful to check for ourselves
+        // to avoid stomping on what should be a setter call. Start by only allowing things
+        // within the initialized length.
+        if (guardHoles) {
+            Address initLength(elements, ObjectElements::offsetOfInitializedLength());
+            masm.branch32(Assembler::BelowOrEqual, initLength, indexReg, &failures);
+        } else {
+            // Guard that we can increase the initialized length.
+            Address capacity(elements, ObjectElements::offsetOfCapacity());
+            masm.branch32(Assembler::BelowOrEqual, capacity, indexReg, &failures);
+
+            // Guard on the initialized length.
+            Address initLength(elements, ObjectElements::offsetOfInitializedLength());
+            masm.branch32(Assembler::Below, initLength, indexReg, &failures);
+
+            // if (initLength == index)
+            Label inBounds;
+            masm.branch32(Assembler::NotEqual, initLength, indexReg, &inBounds);
+            {
+                // Increase initialize length.
+                Register newLength = indexReg;
+                masm.add32(Imm32(1), newLength);
+                masm.store32(newLength, initLength);
+
+                // Increase length if needed.
+                Label bumpedLength;
+                Address length(elements, ObjectElements::offsetOfLength());
+                masm.branch32(Assembler::AboveOrEqual, length, indexReg, &bumpedLength);
+                masm.store32(newLength, length);
+                masm.bind(&bumpedLength);
+
+                // Restore the index.
+                masm.add32(Imm32(-1), newLength);
+                masm.jump(&storeElement);
+            }
+            // else
+            masm.bind(&inBounds);
+        }
+
+        if (cx->zone()->needsIncrementalBarrier())
+            masm.callPreBarrier(target, MIRType::Value);
+
+        // Store the value.
+        if (guardHoles)
+            masm.branchTestMagic(Assembler::Equal, target, &failures);
+        else
+            masm.bind(&storeElement);
+        StoreDenseElement(masm, value, elements, target);
+    }
+    attacher.jumpRejoin(masm);
+
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachDenseElement(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                     HandleObject obj, const Value& idval, bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(canAttachStub());
+
+    if (hasDenseStub())
+        return true;
+
+    bool checkTypeset = false;
+    if (!IsDenseElementSetInlineable(obj, idval, value(), needsTypeBarrier(), &checkTypeset))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+    if (!GenerateSetDenseElement(cx, masm, attacher, obj, idval,
+                                 guardHoles(), object(), id().reg(),
+                                 value(), tempToUnboxIndex(), temp(),
+                                 needsTypeBarrier(), checkTypeset))
+    {
+        return false;
+    }
+
+    setHasDenseStub();
+    const char* message = guardHoles() ?  "dense array (holes)" : "dense array";
+    return linkAndAttachStub(cx, masm, attacher, ion, message,
+                             JS::TrackedOutcome::ICSetElemStub_Dense);
+}
+
+static bool
+GenerateSetTypedArrayElement(JSContext* cx, MacroAssembler& masm, IonCache::StubAttacher& attacher,
+                             HandleObject tarr, Register object, TypedOrValueRegister index,
+                             const ConstantOrRegister& value, Register tempUnbox, Register temp,
+                             FloatRegister tempDouble, FloatRegister tempFloat32)
+{
+    Label failures, done, popObjectAndFail;
+
+    // Guard on the shape.
+    Shape* shape = tarr->as<TypedArrayObject>().lastProperty();
+    if (!shape)
+        return false;
+    masm.branchTestObjShape(Assembler::NotEqual, object, shape, &failures);
+
+    // Ensure the index is an int32.
+    Register indexReg;
+    if (index.hasValue()) {
+        ValueOperand val = index.valueReg();
+        masm.branchTestInt32(Assembler::NotEqual, val, &failures);
+
+        indexReg = masm.extractInt32(val, tempUnbox);
+    } else {
+        MOZ_ASSERT(!index.typedReg().isFloat());
+        indexReg = index.typedReg().gpr();
+    }
+
+    // Guard on the length.
+    Address length(object, TypedArrayObject::lengthOffset());
+    masm.unboxInt32(length, temp);
+    masm.branch32(Assembler::BelowOrEqual, temp, indexReg, &done);
+
+    // Load the elements vector.
+    Register elements = temp;
+    masm.loadPtr(Address(object, TypedArrayObject::dataOffset()), elements);
+
+    // Set the value.
+    Scalar::Type arrayType = tarr->as<TypedArrayObject>().type();
+    int width = Scalar::byteSize(arrayType);
+    BaseIndex target(elements, indexReg, ScaleFromElemWidth(width));
+
+    if (arrayType == Scalar::Float32) {
+        MOZ_ASSERT_IF(hasUnaliasedDouble(), tempFloat32 != InvalidFloatReg);
+        FloatRegister tempFloat = hasUnaliasedDouble() ? tempFloat32 : tempDouble;
+        if (!masm.convertConstantOrRegisterToFloat(cx, value, tempFloat, &failures))
+            return false;
+        masm.storeToTypedFloatArray(arrayType, tempFloat, target);
+    } else if (arrayType == Scalar::Float64) {
+        if (!masm.convertConstantOrRegisterToDouble(cx, value, tempDouble, &failures))
+            return false;
+        masm.storeToTypedFloatArray(arrayType, tempDouble, target);
+    } else {
+        // On x86 we only have 6 registers available to use, so reuse the object
+        // register to compute the intermediate value to store and restore it
+        // afterwards.
+        masm.push(object);
+
+        if (arrayType == Scalar::Uint8Clamped) {
+            if (!masm.clampConstantOrRegisterToUint8(cx, value, tempDouble, object,
+                                                     &popObjectAndFail))
+            {
+                return false;
+            }
+        } else {
+            if (!masm.truncateConstantOrRegisterToInt32(cx, value, tempDouble, object,
+                                                        &popObjectAndFail))
+            {
+                return false;
+            }
+        }
+        masm.storeToTypedIntArray(arrayType, object, target);
+
+        masm.pop(object);
+    }
+
+    // Out-of-bound writes jump here as they are no-ops.
+    masm.bind(&done);
+    attacher.jumpRejoin(masm);
+
+    if (popObjectAndFail.used()) {
+        masm.bind(&popObjectAndFail);
+        masm.pop(object);
+    }
+
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+    return true;
+}
+
+bool
+SetPropertyIC::tryAttachTypedArrayElement(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                                          HandleObject obj, HandleValue idval, HandleValue val,
+                                          bool* emitted)
+{
+    MOZ_ASSERT(!*emitted);
+    MOZ_ASSERT(canAttachStub());
+
+    if (!IsTypedArrayElementSetInlineable(obj, idval, val))
+        return true;
+
+    *emitted = true;
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+    if (!GenerateSetTypedArrayElement(cx, masm, attacher, obj,
+                                      object(), id().reg(), value(),
+                                      tempToUnboxIndex(), temp(), tempDouble(), tempFloat32()))
+    {
+        return false;
+    }
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "typed array",
+                             JS::TrackedOutcome::ICSetElemStub_TypedArray);
+}
+
+bool
+BindNameIC::attachGlobal(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                         HandleObject envChain)
+{
+    MOZ_ASSERT(envChain->is<GlobalObject>());
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    // Guard on the env chain.
+    attacher.branchNextStub(masm, Assembler::NotEqual, environmentChainReg(),
+                            ImmGCPtr(envChain));
+    masm.movePtr(ImmGCPtr(envChain), outputReg());
+
+    attacher.jumpRejoin(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "global");
+}
+
+static inline void
+GenerateEnvironmentChainGuard(MacroAssembler& masm, JSObject* envObj,
+                              Register envObjReg, Shape* shape, Label* failures)
+{
+    if (envObj->is<CallObject>()) {
+        // We can skip a guard on the call object if the script's bindings are
+        // guaranteed to be immutable (and thus cannot introduce shadowing
+        // variables).
+        CallObject* callObj = &envObj->as<CallObject>();
+        JSFunction* fun = &callObj->callee();
+        // The function might have been relazified under rare conditions.
+        // In that case, we pessimistically create the guard, as we'd
+        // need to root various pointers to delazify,
+        if (fun->hasScript()) {
+            JSScript* script = fun->nonLazyScript();
+            if (!script->funHasExtensibleScope())
+                return;
+        }
+    } else if (envObj->is<GlobalObject>()) {
+        // If this is the last object on the scope walk, and the property we've
+        // found is not configurable, then we don't need a shape guard because
+        // the shape cannot be removed.
+        if (shape && !shape->configurable())
+            return;
+    }
+
+    Address shapeAddr(envObjReg, ShapedObject::offsetOfShape());
+    masm.branchPtr(Assembler::NotEqual, shapeAddr,
+                   ImmGCPtr(envObj->as<NativeObject>().lastProperty()), failures);
+}
+
+static void
+GenerateEnvironmentChainGuards(MacroAssembler& masm, JSObject* envChain, JSObject* holder,
+                               Register outputReg, Label* failures, bool skipLastGuard = false)
+{
+    JSObject* tobj = envChain;
+
+    // Walk up the env chain. Note that IsCacheableEnvironmentChain guarantees the
+    // |tobj == holder| condition terminates the loop.
+    while (true) {
+        MOZ_ASSERT(IsCacheableEnvironment(tobj) || tobj->is<GlobalObject>());
+
+        if (skipLastGuard && tobj == holder)
+            break;
+
+        GenerateEnvironmentChainGuard(masm, tobj, outputReg, nullptr, failures);
+
+        if (tobj == holder)
+            break;
+
+        // Load the next link.
+        tobj = &tobj->as<EnvironmentObject>().enclosingEnvironment();
+        masm.extractObject(Address(outputReg, EnvironmentObject::offsetOfEnclosingEnvironment()),
+                           outputReg);
+    }
+}
+
+bool
+BindNameIC::attachNonGlobal(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                            HandleObject envChain, HandleObject holder)
+{
+    MOZ_ASSERT(IsCacheableEnvironment(envChain));
+
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    // Guard on the shape of the env chain.
+    Label failures;
+    attacher.branchNextStubOrLabel(masm, Assembler::NotEqual,
+                                   Address(environmentChainReg(), ShapedObject::offsetOfShape()),
+                                   ImmGCPtr(envChain->as<NativeObject>().lastProperty()),
+                                   holder != envChain ? &failures : nullptr);
+
+    if (holder != envChain) {
+        JSObject* parent = &envChain->as<EnvironmentObject>().enclosingEnvironment();
+        masm.extractObject(Address(environmentChainReg(),
+                                   EnvironmentObject::offsetOfEnclosingEnvironment()),
+                           outputReg());
+
+        GenerateEnvironmentChainGuards(masm, parent, holder, outputReg(), &failures);
+    } else {
+        masm.movePtr(environmentChainReg(), outputReg());
+    }
+
+    // At this point outputReg holds the object on which the property
+    // was found, so we're done.
+    attacher.jumpRejoin(masm);
+
+    // All failures flow to here, so there is a common point to patch.
+    if (holder != envChain) {
+        masm.bind(&failures);
+        attacher.jumpNextStub(masm);
+    }
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "non-global");
+}
+
+static bool
+IsCacheableNonGlobalEnvironmentChain(JSObject* envChain, JSObject* holder)
+{
+    while (true) {
+        if (!IsCacheableEnvironment(envChain)) {
+            JitSpew(JitSpew_IonIC, "Non-cacheable object on env chain");
+            return false;
+        }
+
+        if (envChain == holder)
+            return true;
+
+        envChain = &envChain->as<EnvironmentObject>().enclosingEnvironment();
+        if (!envChain) {
+            JitSpew(JitSpew_IonIC, "env chain indirect hit");
+            return false;
+        }
+    }
+
+    MOZ_CRASH("Invalid env chain");
+}
+
+JSObject*
+BindNameIC::update(JSContext* cx, HandleScript outerScript, size_t cacheIndex,
+                   HandleObject envChain)
+{
+    IonScript* ion = outerScript->ionScript();
+    BindNameIC& cache = ion->getCache(cacheIndex).toBindName();
+    HandlePropertyName name = cache.name();
+
+    RootedObject holder(cx);
+    if (!LookupNameUnqualified(cx, name, envChain, &holder))
+        return nullptr;
+
+    // Stop generating new stubs once we hit the stub count limit, see
+    // GetPropertyCache.
+    if (cache.canAttachStub()) {
+        if (envChain->is<GlobalObject>()) {
+            if (!cache.attachGlobal(cx, outerScript, ion, envChain))
+                return nullptr;
+        } else if (IsCacheableNonGlobalEnvironmentChain(envChain, holder)) {
+            if (!cache.attachNonGlobal(cx, outerScript, ion, envChain, holder))
+                return nullptr;
+        } else {
+            JitSpew(JitSpew_IonIC, "BINDNAME uncacheable env chain");
+        }
+    }
+
+    return holder;
+}
+
+bool
+NameIC::attachReadSlot(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                       HandleObject envChain, HandleObject holderBase,
+                       HandleNativeObject holder, HandleShape shape)
+{
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    Label failures;
+    StubAttacher attacher(*this);
+
+    Register scratchReg = outputReg().valueReg().scratchReg();
+
+    // Don't guard the base of the proto chain the name was found on. It will be guarded
+    // by GenerateReadSlot().
+    masm.mov(environmentChainReg(), scratchReg);
+    GenerateEnvironmentChainGuards(masm, envChain, holderBase, scratchReg, &failures,
+                             /* skipLastGuard = */true);
+
+    // GenerateEnvironmentChain leaves the last env chain in scratchReg, even though it
+    // doesn't generate the extra guard.
+    //
+    // NAME ops must do their own TDZ checks.
+    GenerateReadSlot(cx, ion, masm, attacher, CheckTDZ, holderBase, holder, shape, scratchReg,
+                     outputReg(), failures.used() ? &failures : nullptr);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "generic",
+                             JS::TrackedOutcome::ICNameStub_ReadSlot);
+}
+
+static bool
+IsCacheableEnvironmentChain(JSObject* envChain, JSObject* obj)
+{
+    JSObject* obj2 = envChain;
+    while (obj2) {
+        if (!IsCacheableEnvironment(obj2) && !obj2->is<GlobalObject>())
+            return false;
+
+        // Stop once we hit the global or target obj.
+        if (obj2->is<GlobalObject>() || obj2 == obj)
+            break;
+
+        obj2 = obj2->enclosingEnvironment();
+    }
+
+    return obj == obj2;
+}
+
+static bool
+IsCacheableNameReadSlot(HandleObject envChain, HandleObject obj,
+                        HandleObject holder, HandleShape shape, jsbytecode* pc,
+                        const TypedOrValueRegister& output)
+{
+    if (!shape)
+        return false;
+    if (!obj->isNative())
+        return false;
+
+    if (obj->is<GlobalObject>()) {
+        // Support only simple property lookups.
+        if (!IsCacheableGetPropReadSlotForIonOrCacheIR(obj, holder, shape) &&
+            !IsCacheableNoProperty(obj, holder, shape, pc, output))
+            return false;
+    } else if (obj->is<ModuleEnvironmentObject>()) {
+        // We don't yet support lookups in a module environment.
+        return false;
+    } else if (obj->is<CallObject>()) {
+        MOZ_ASSERT(obj == holder);
+        if (!shape->hasDefaultGetter())
+            return false;
+    } else {
+        // We don't yet support lookups on Block or DeclEnv objects.
+        return false;
+    }
+
+    return IsCacheableEnvironmentChain(envChain, obj);
+}
+
+bool
+NameIC::attachCallGetter(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                         HandleObject envChain, HandleObject obj, HandleObject holder,
+                         HandleShape shape, void* returnAddr)
+{
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    StubAttacher attacher(*this);
+
+    Label failures;
+    Register scratchReg = outputReg().valueReg().scratchReg();
+
+    // Don't guard the base of the proto chain the name was found on. It will be guarded
+    // by GenerateCallGetter().
+    masm.mov(environmentChainReg(), scratchReg);
+    GenerateEnvironmentChainGuards(masm, envChain, obj, scratchReg, &failures,
+                             /* skipLastGuard = */true);
+
+    // GenerateEnvironmentChain leaves the last env chain in scratchReg, even though it
+    // doesn't generate the extra guard.
+    if (!GenerateCallGetter(cx, ion, masm, attacher, obj, holder, shape, liveRegs_,
+                            scratchReg, outputReg(), returnAddr,
+                            failures.used() ? &failures : nullptr))
+    {
+         return false;
+    }
+
+    const char* attachKind = "name getter";
+    return linkAndAttachStub(cx, masm, attacher, ion, attachKind,
+                             JS::TrackedOutcome::ICNameStub_CallGetter);
+}
+
+static bool
+IsCacheableNameCallGetter(HandleObject envChain, HandleObject obj, HandleObject holder,
+                          HandleShape shape)
+{
+    if (!shape)
+        return false;
+    if (!obj->is<GlobalObject>())
+        return false;
+
+    if (!IsCacheableEnvironmentChain(envChain, obj))
+        return false;
+
+    return IsCacheableGetPropCallNative(obj, holder, shape) ||
+        IsCacheableGetPropCallPropertyOp(obj, holder, shape) ||
+        IsCacheableGetPropCallScripted(obj, holder, shape);
+}
+
+bool
+NameIC::attachTypeOfNoProperty(JSContext* cx, HandleScript outerScript, IonScript* ion,
+                               HandleObject envChain)
+{
+    MacroAssembler masm(cx, ion, outerScript, profilerLeavePc_);
+    Label failures;
+    StubAttacher attacher(*this);
+
+    Register scratchReg = outputReg().valueReg().scratchReg();
+
+    masm.movePtr(environmentChainReg(), scratchReg);
+
+    // Generate env chain guards.
+    // Since the property was not defined on any object, iterate until reaching the global.
+    JSObject* tobj = envChain;
+    while (true) {
+        GenerateEnvironmentChainGuard(masm, tobj, scratchReg, nullptr, &failures);
+
+        if (tobj->is<GlobalObject>())
+            break;
+
+        // Load the next link.
+        tobj = &tobj->as<EnvironmentObject>().enclosingEnvironment();
+        masm.extractObject(Address(scratchReg, EnvironmentObject::offsetOfEnclosingEnvironment()),
+                           scratchReg);
+    }
+
+    masm.moveValue(UndefinedValue(), outputReg().valueReg());
+    attacher.jumpRejoin(masm);
+
+    masm.bind(&failures);
+    attacher.jumpNextStub(masm);
+
+    return linkAndAttachStub(cx, masm, attacher, ion, "generic",
+                             JS::TrackedOutcome::ICNameStub_TypeOfNoProperty);
+}
+
+static bool
+IsCacheableNameNoProperty(HandleObject envChain, HandleObject obj,
+                          HandleObject holder, HandleShape shape, jsbytecode* pc,
+                          NameIC& cache)
+{
+    if (cache.isTypeOf() && !shape) {
+        MOZ_ASSERT(!obj);
+        MOZ_ASSERT(!holder);
+        MOZ_ASSERT(envChain);
+
+        // Assert those extra things checked by IsCacheableNoProperty().
+        MOZ_ASSERT(cache.outputReg().hasValue());
+        MOZ_ASSERT(pc != nullptr);
+
+        return true;
+    }
+
+    return false;
+}
+
+bool
+NameIC::update(JSContext* cx, HandleScript outerScript, size_t cacheIndex, HandleObject envChain,
+               MutableHandleValue vp)
+{
+    IonScript* ion = outerScript->ionScript();
+
+    NameIC& cache = ion->getCache(cacheIndex).toName();
+    RootedPropertyName name(cx, cache.name());
+
+    RootedScript script(cx);
+    jsbytecode* pc;
+    cache.getScriptedLocation(&script, &pc);
+
+    RootedObject obj(cx);
+    RootedObject holder(cx);
+    RootedShape shape(cx);
+    if (!LookupName(cx, name, envChain, &obj, &holder, &shape))
+        return false;
+
+    // Look first. Don't generate cache entries if the lookup fails.
+    if (cache.isTypeOf()) {
+        if (!FetchName<true>(cx, obj, holder, name, shape, vp))
+            return false;
+    } else {
+        if (!FetchName<false>(cx, obj, holder, name, shape, vp))
+            return false;
+    }
+
+    if (cache.canAttachStub()) {
+        if (IsCacheableNameReadSlot(envChain, obj, holder, shape, pc, cache.outputReg())) {
+            if (!cache.attachReadSlot(cx, outerScript, ion, envChain, obj,
+                                      holder.as<NativeObject>(), shape))
+            {
+                return false;
+            }
+        } else if (IsCacheableNameCallGetter(envChain, obj, holder, shape)) {
+            void* returnAddr = GetReturnAddressToIonCode(cx);
+            if (!cache.attachCallGetter(cx, outerScript, ion, envChain, obj, holder, shape,
+                                        returnAddr))
+            {
+                return false;
+            }
+        } else if (IsCacheableNameNoProperty(envChain, obj, holder, shape, pc, cache)) {
+            if (!cache.attachTypeOfNoProperty(cx, outerScript, ion, envChain))
+                return false;
+        }
+    }
+
+    // Monitor changes to cache entry.
+    TypeScript::Monitor(cx, script, pc, vp);
+
+    return true;
+}