Remove concept of AppDomains from the GC (#24536)

* Remove concept of AppDomains from the GC
- Leave constructs allowing for multiple handle tables, as scenarios for that have been proposed
- Remove FEATURE_APPDOMAIN_RESOURCE_MONITORING

44 files changed, 43 insertions, 1754 deletions

diff --git a/Documentation/project-docs/clr-configuration-knobs.md b/Documentation/project-docs/clr-configuration-knobs.md
index 42f1b647e3..9786bc4b8d 100644
--- a/Documentation/project-docs/clr-configuration-knobs.md
+++ b/Documentation/project-docs/clr-configuration-knobs.md
@@ -72,12 +72,6 @@ Name | Description | Type | Class | Default Value | Flags
 `ADTakeSnapShot` | Superseded by test hooks | `DWORD` | `INTERNAL` | `0` |
 `EnableFullDebug` | Heavy-weight checking for AD boundary violations (AD leaks) | `DWORD` | `INTERNAL` | |
 
-#### ARM Configuration Knobs
-
-Name | Description | Type | Class | Default Value | Flags
------|-------------|------|-------|---------------|-------
-`ARMEnabled` | AppDomain Resource Monitoring. Set to 1 to enable it | `DWORD` | `UNSUPPORTED` | `(DWORD)0` |
-
 #### Assembly Loader Configuration Knobs
 
 Name | Description | Type | Class | Default Value | Flags
diff --git a/src/debug/daccess/daccess.cpp b/src/debug/daccess/daccess.cpp
index 0d1dc56e03..08c44e2b8c 100644
--- a/src/debug/daccess/daccess.cpp
+++ b/src/debug/daccess/daccess.cpp
@@ -8472,7 +8472,6 @@ StackWalkAction DacStackReferenceWalker::Callback(CrawlFrame *pCF, VOID *pData)
 
     MethodDesc *pMD = pCF->GetFunction();
     gcctx->sc->pMD = pMD;
-    gcctx->sc->pCurrentDomain = pCF->GetAppDomain();
 
     PREGDISPLAY pRD = pCF->GetRegisterSet();
     dsc->sp = (TADDR)GetRegdisplaySP(pRD);;
diff --git a/src/debug/daccess/dacdbiimpl.cpp b/src/debug/daccess/dacdbiimpl.cpp
index 4d97298838..8d02590727 100644
--- a/src/debug/daccess/dacdbiimpl.cpp
+++ b/src/debug/daccess/dacdbiimpl.cpp
@@ -5716,8 +5716,7 @@ ULONG DacDbiInterfaceImpl::GetAppDomainIdFromVmObjectHandle(VMPTR_OBJECTHANDLE v
 {
     DD_ENTER_MAY_THROW;
 
-    OBJECTHANDLE handle = (OBJECTHANDLE) vmHandle.GetDacPtr();
-    return HndGetHandleADIndex(handle).m_dwIndex;
+    return DefaultADID;
 }
 
 // Get the target address from a VMPTR_OBJECTHANDLE, i.e., the handle address
@@ -7553,7 +7552,7 @@ void DacStackReferenceWalker::GCEnumCallbackDac(LPVOID hCallback, OBJECTREF *pOb
     DacGcReference *data = dsc->pWalker->GetNextObject<DacGcReference>(dsc);
     if (data != NULL)
     {
-        data->vmDomain.SetDacTargetPtr(dac_cast<PTR_AppDomain>(dsc->pCurrentDomain).GetAddr());
+        data->vmDomain.SetDacTargetPtr(AppDomain::GetCurrentDomain().GetAddr());
         if (obj)
             data->pObject = obj | 1;
         else if (loc.targetPtr)
@@ -7589,7 +7588,7 @@ void DacStackReferenceWalker::GCReportCallbackDac(PTR_PTR_Object ppObj, ScanCont
     DacGcReference *data = dsc->pWalker->GetNextObject<DacGcReference>(dsc);
     if (data != NULL)
     {
-        data->vmDomain.SetDacTargetPtr(dac_cast<PTR_AppDomain>(dsc->pCurrentDomain).GetAddr());
+        data->vmDomain.SetDacTargetPtr(AppDomain::GetCurrentDomain().GetAddr());
         data->objHnd.SetDacTargetPtr(obj);
         data->dwType = CorReferenceStack;
         data->i64ExtraData = 0;
diff --git a/src/debug/daccess/gcinterface.dac.h b/src/debug/daccess/gcinterface.dac.h
index c7765ef364..87207f41a3 100644
--- a/src/debug/daccess/gcinterface.dac.h
+++ b/src/debug/daccess/gcinterface.dac.h
@@ -44,9 +44,6 @@ GC_DAC_VISIBLE
 OBJECTREF HndFetchHandle(OBJECTHANDLE handle);
 
 GC_DAC_VISIBLE
-struct ADIndex HndGetHandleADIndex(OBJECTHANDLE handle);
-
-GC_DAC_VISIBLE
 uintptr_t HndGetHandleExtraInfo(OBJECTHANDLE handle);
 
 #endif // DACCESS_COMPILE
diff --git a/src/gc/CMakeLists.txt b/src/gc/CMakeLists.txt
index e3e171ebf1..ab9f3a0bad 100644
--- a/src/gc/CMakeLists.txt
+++ b/src/gc/CMakeLists.txt
@@ -2,9 +2,6 @@ set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
 # Local GC meta-issue: https://github.com/dotnet/coreclr/issues/11518
 
-# https://github.com/dotnet/coreclr/issues/11517
-remove_definitions(-DFEATURE_APPDOMAIN_RESOURCE_MONITORING)
-
 # https://github.com/dotnet/coreclr/issues/11516
 remove_definitions(-DSTRESS_HEAP)
 
diff --git a/src/gc/env/etmdummy.h b/src/gc/env/etmdummy.h
index 2b47a46e4e..f2c76d4b8d 100644
--- a/src/gc/env/etmdummy.h
+++ b/src/gc/env/etmdummy.h
@@ -47,7 +47,7 @@
 #define FireEtwGCMarkHandles(HeapNum, ClrInstanceID) 0
 #define FireEtwGCMarkOlderGenerationRoots(HeapNum, ClrInstanceID) 0
 #define FireEtwFinalizeObject(TypeID, ObjectID, ClrInstanceID) 0
-#define FireEtwSetGCHandle(HandleID, ObjectID, Kind, Generation, AppDomainID, ClrInstanceID) 0
+#define FireEtwSetGCHandle(HandleID, ObjectID, Kind, Generation, ClrInstanceID) 0
 #define FireEtwDestroyGCHandle(HandleID, ClrInstanceID) 0
 #define FireEtwGCSampledObjectAllocationLow(Address, TypeID, ObjectCountForTypeSample, TotalSizeForTypeSample, ClrInstanceID) 0
 #define FireEtwPinObjectAtGCTime(HandleID, ObjectID, ObjectSize, TypeName, ClrInstanceID) 0
@@ -376,7 +376,7 @@
 #define FireEtwFailFast(FailFastUserMessage, FailedEIP, OSExitCode, ClrExitCode, ClrInstanceID) 0
 #define FireEtwPrvFinalizeObject(TypeID, ObjectID, ClrInstanceID, TypeName) 0
 #define FireEtwCCWRefCountChange(HandleID, ObjectID, COMInterfacePointer, NewRefCount, AppDomainID, ClassName, NameSpace, Operation, ClrInstanceID) 0
-#define FireEtwPrvSetGCHandle(HandleID, ObjectID, Kind, Generation, AppDomainID, ClrInstanceID) 0
+#define FireEtwPrvSetGCHandle(HandleID, ObjectID, Kind, Generation, ClrInstanceID) 0
 #define FireEtwPrvDestroyGCHandle(HandleID, ClrInstanceID) 0
 #define FireEtwFusionMessageEvent(ClrInstanceID, Prepend, Message) 0
 #define FireEtwFusionErrorCodeEvent(ClrInstanceID, Category, ErrorCode) 0
diff --git a/src/gc/env/gcenv.base.h b/src/gc/env/gcenv.base.h
index 614b84ab23..46ad366e62 100644
--- a/src/gc/env/gcenv.base.h
+++ b/src/gc/env/gcenv.base.h
@@ -538,22 +538,4 @@ inline bool FitsInU1(uint64_t val)
     return val == (uint64_t)(uint8_t)val;
 }
 
-// -----------------------------------------------------------------------------------------------------------
-//
-// AppDomain emulation. The we don't have these in Redhawk so instead we emulate the bare minimum of the API
-// touched by the GC/HandleTable and pretend we have precisely one (default) appdomain.
-//
-
-#define RH_DEFAULT_DOMAIN_ID 1
-
-struct ADIndex
-{
-    DWORD m_dwIndex;
-
-    ADIndex () : m_dwIndex(RH_DEFAULT_DOMAIN_ID) {}
-    explicit ADIndex (DWORD id) : m_dwIndex(id) {}
-    BOOL operator==(const ADIndex& ad) const { return m_dwIndex == ad.m_dwIndex; }
-    BOOL operator!=(const ADIndex& ad) const { return m_dwIndex != ad.m_dwIndex; }
-};
-
 #endif // __GCENV_BASE_INCLUDED__
diff --git a/src/gc/env/gcenv.ee.h b/src/gc/env/gcenv.ee.h
index b9918ec5b7..819f64882a 100644
--- a/src/gc/env/gcenv.ee.h
+++ b/src/gc/env/gcenv.ee.h
@@ -71,7 +71,6 @@ public:
     static void EnableFinalization(bool foundFinalizers);
 
     static void HandleFatalError(unsigned int exitCode);
-    static bool ShouldFinalizeObjectForUnload(void* pDomain, Object* obj);
     static bool EagerFinalized(Object* obj);
     static MethodTable* GetFreeObjectMethodTable();
     static bool GetBooleanConfigValue(const char* key, bool* value);
@@ -85,12 +84,7 @@ public:
     static void WalkAsyncPinned(Object* object, void* context, void(*callback)(Object*, Object*, void*));
     static IGCToCLREventSink* EventSink();
 
-    static uint32_t GetDefaultDomainIndex();
-    static void *GetAppDomainAtIndex(uint32_t appDomainIndex);
-    static bool AppDomainCanAccessHandleTable(uint32_t appDomainID);
-    static uint32_t GetIndexOfAppDomainBeingUnloaded();
     static uint32_t GetTotalNumSizedRefHandles();
-    static bool AppDomainIsRudeUnload(void *appDomain);
 
     static bool AnalyzeSurvivorsRequested(int condemnedGeneration);
     static void AnalyzeSurvivorsFinished(int condemnedGeneration);
diff --git a/src/gc/gc.cpp b/src/gc/gc.cpp
index c6a858c8fa..3c8345922f 100644
--- a/src/gc/gc.cpp
+++ b/src/gc/gc.cpp
@@ -11528,14 +11528,6 @@ void gc_heap::adjust_limit_clr (uint8_t* start, size_t limit_size, size_t size,
     acontext->alloc_bytes += added_bytes;
     total_alloc_bytes     += added_bytes;
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableAppDomainMonitoring)
-    {
-        GCToEEInterface::RecordAllocatedBytesForHeap(limit_size, heap_number);
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
-
     uint8_t* saved_used = 0;
 
     if (seg)
@@ -12085,13 +12077,6 @@ void gc_heap::bgc_loh_alloc_clr (uint8_t* alloc_start,
 {
     make_unused_array (alloc_start, size);
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableAppDomainMonitoring)
-    {
-        GCToEEInterface::RecordAllocatedBytesForHeap(size, heap_number);
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     size_t size_of_array_base = sizeof(ArrayBase);
 
     bgc_alloc_lock->loh_alloc_done_with_index (lock_index);
@@ -19084,10 +19069,6 @@ gc_heap::scan_background_roots (promote_func* fn, int hn, ScanContext *pSC)
 
     pSC->thread_number = hn;
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    pSC->pCurrentDomain = 0;
-#endif
-
     BOOL relocate_p = (fn == &GCHeap::Relocate);
 
     dprintf (3, ("Scanning background mark list"));
@@ -20295,22 +20276,6 @@ void gc_heap::mark_phase (int condemned_gen_number, BOOL mark_only_p)
         // scan for deleted entries in the syncblk cache
         GCScan::GcWeakPtrScanBySingleThread (condemned_gen_number, max_generation, &sc);
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-        if (g_fEnableAppDomainMonitoring)
-        {
-            size_t promoted_all_heaps = 0;
-#ifdef MULTIPLE_HEAPS
-            for (int i = 0; i < n_heaps; i++)
-            {
-                promoted_all_heaps += promoted_bytes (i);
-            }
-#else
-            promoted_all_heaps = promoted_bytes (heap_number);
-#endif //MULTIPLE_HEAPS
-            GCToEEInterface::RecordTotalSurvivedBytes(promoted_all_heaps);
-        }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifdef MULTIPLE_HEAPS
 
 #ifdef MARK_LIST
@@ -34589,26 +34554,11 @@ void GCHeap::Promote(Object** ppObject, ScanContext* sc, uint32_t flags)
             hp->pin_object (o, (uint8_t**) ppObject, hp->gc_low, hp->gc_high);
 #endif //STRESS_PINNING
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    size_t promoted_size_begin = hp->promoted_bytes (thread);
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     if ((o >= hp->gc_low) && (o < hp->gc_high))
     {
         hpt->mark_object_simple (&o THREAD_NUMBER_ARG);
     }
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    size_t promoted_size_end = hp->promoted_bytes (thread);
-    if (g_fEnableAppDomainMonitoring)
-    {
-        if (sc->pCurrentDomain)
-        {
-            GCToEEInterface::RecordSurvivedBytesForHeap((promoted_size_end - promoted_size_begin), thread, sc->pCurrentDomain);
-        }
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     STRESS_LOG_ROOT_PROMOTE(ppObject, o, o ? header(o)->GetMethodTable() : NULL);
 }
 
@@ -35544,13 +35494,6 @@ void gc_heap::do_pre_gc()
 #endif //BACKGROUND_GC
         }
     }
-
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableAppDomainMonitoring)
-    {
-        GCToEEInterface::ResetTotalSurvivedBytes();
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
 }
 
 #ifdef GC_CONFIG_DRIVEN
@@ -35798,13 +35741,6 @@ void gc_heap::do_post_gc()
     }
 
     GCHeap::UpdatePostGCCounters();
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    //if (g_fEnableARM)
-    //{
-    //    SystemDomain::GetADSurvivedBytes();
-    //}
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifdef STRESS_LOG
     STRESS_LOG_GC_END(VolatileLoad(&settings.gc_index),
                       (uint32_t)settings.condemned_generation,
@@ -36551,23 +36487,6 @@ size_t GCHeap::GetFinalizablePromotedCount()
 #endif //MULTIPLE_HEAPS
 }
 
-bool GCHeap::FinalizeAppDomain(void *pDomain, bool fRunFinalizers)
-{
-#ifdef MULTIPLE_HEAPS
-    bool foundp = false;
-    for (int hn = 0; hn < gc_heap::n_heaps; hn++)
-    {
-        gc_heap* hp = gc_heap::g_heaps [hn];
-        if (hp->finalize_queue->FinalizeAppDomain (pDomain, fRunFinalizers))
-            foundp = true;
-    }
-    return foundp;
-
-#else //MULTIPLE_HEAPS
-    return pGenGCHeap->finalize_queue->FinalizeAppDomain (pDomain, fRunFinalizers);
-#endif //MULTIPLE_HEAPS
-}
-
 bool GCHeap::ShouldRestartFinalizerWatchDog()
 {
     // This condition was historically used as part of the condition to detect finalizer thread timeouts
@@ -36872,88 +36791,6 @@ CFinalize::GetNumberFinalizableObjects()
         (g_fFinalizerRunOnShutDown ? m_Array : SegQueue(FinalizerListSeg));
 }
 
-BOOL
-CFinalize::FinalizeSegForAppDomain (void *pDomain, 
-                                    BOOL fRunFinalizers, 
-                                    unsigned int Seg)
-{
-    BOOL finalizedFound = FALSE;
-    Object** endIndex = SegQueue (Seg);
-    for (Object** i = SegQueueLimit (Seg)-1; i >= endIndex ;i--)
-    {
-        CObjectHeader* obj = (CObjectHeader*)*i;
-
-        // Objects are put into the finalization queue before they are complete (ie their methodtable
-        // may be null) so we must check that the object we found has a method table before checking
-        // if it has the index we are looking for. If the methodtable is null, it can't be from the
-        // unloading domain, so skip it.
-        if (method_table(obj) == NULL)
-        {
-            continue;
-        }
-
-        // does the EE actually want us to finalize this object?
-        if (!GCToEEInterface::ShouldFinalizeObjectForUnload(pDomain, obj))
-        {
-            continue;
-        }
-
-        if (!fRunFinalizers || (obj->GetHeader()->GetBits()) & BIT_SBLK_FINALIZER_RUN)
-        {
-            //remove the object because we don't want to
-            //run the finalizer
-            MoveItem (i, Seg, FreeList);
-            //Reset the bit so it will be put back on the queue
-            //if resurrected and re-registered.
-            obj->GetHeader()->ClrBit (BIT_SBLK_FINALIZER_RUN);
-        }
-        else
-        {
-            if (method_table(obj)->HasCriticalFinalizer())
-            {
-                finalizedFound = TRUE;
-                MoveItem (i, Seg, CriticalFinalizerListSeg);
-            }
-            else
-            {
-                if (GCToEEInterface::AppDomainIsRudeUnload(pDomain))
-                {
-                    MoveItem (i, Seg, FreeList);
-                }
-                else
-                {
-                    finalizedFound = TRUE;
-                    MoveItem (i, Seg, FinalizerListSeg);
-                }
-            }
-        }
-    }
-
-    return finalizedFound;
-}
-
-bool
-CFinalize::FinalizeAppDomain (void *pDomain, bool fRunFinalizers)
-{
-    bool finalizedFound = false;
-
-    unsigned int startSeg = gen_segment (max_generation);
-
-    EnterFinalizeLock();
-
-    for (unsigned int Seg = startSeg; Seg <= gen_segment (0); Seg++)
-    {
-        if (FinalizeSegForAppDomain (pDomain, fRunFinalizers, Seg))
-        {
-            finalizedFound = true;
-        }
-    }
-
-    LeaveFinalizeLock();
-
-    return finalizedFound;
-}
-
 void
 CFinalize::MoveItem (Object** fromIndex,
                      unsigned int fromSeg,
@@ -37001,12 +36838,6 @@ CFinalize::GcScanRoots (promote_func* fn, int hn, ScanContext *pSC)
         Object* o = *po;
         //dprintf (3, ("scan freacheable %Ix", (size_t)o));
         dprintf (3, ("scan f %Ix", (size_t)o));
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-        if (g_fEnableAppDomainMonitoring)
-        {
-            pSC->pCurrentDomain = GCToEEInterface::GetAppDomainForObject(o);
-        }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
 
         (*fn)(po, pSC, 0);
     }
diff --git a/src/gc/gcenv.ee.standalone.inl b/src/gc/gcenv.ee.standalone.inl
index 7a9b8b1014..be318dc8f0 100644
--- a/src/gc/gcenv.ee.standalone.inl
+++ b/src/gc/gcenv.ee.standalone.inl
@@ -191,12 +191,6 @@ inline void GCToEEInterface::HandleFatalError(unsigned int exitCode)
     g_theGCToCLR->HandleFatalError(exitCode);
 }
 
-inline bool GCToEEInterface::ShouldFinalizeObjectForUnload(void* pDomain, Object* obj)
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->ShouldFinalizeObjectForUnload(pDomain, obj);
-}
-
 inline bool GCToEEInterface::EagerFinalized(Object* obj)
 {
     assert(g_theGCToCLR != nullptr);
@@ -269,42 +263,12 @@ inline IGCToCLREventSink* GCToEEInterface::EventSink()
     return g_theGCToCLR->EventSink();
 }
 
-inline uint32_t GCToEEInterface::GetDefaultDomainIndex()
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->GetDefaultDomainIndex();   
-}
-
-inline void *GCToEEInterface::GetAppDomainAtIndex(uint32_t appDomainIndex)
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->GetAppDomainAtIndex(appDomainIndex);
-}
-
-inline bool GCToEEInterface::AppDomainCanAccessHandleTable(uint32_t appDomainID)
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->AppDomainCanAccessHandleTable(appDomainID);
-}
-
-inline uint32_t GCToEEInterface::GetIndexOfAppDomainBeingUnloaded()
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->GetIndexOfAppDomainBeingUnloaded();
-}
-
 inline uint32_t GCToEEInterface::GetTotalNumSizedRefHandles()
 {
     assert(g_theGCToCLR != nullptr);
     return g_theGCToCLR->GetTotalNumSizedRefHandles();
 }
 
-inline bool GCToEEInterface::AppDomainIsRudeUnload(void *appDomain)
-{
-    assert(g_theGCToCLR != nullptr);
-    return g_theGCToCLR->AppDomainIsRudeUnload(appDomain);
-}
-
 inline bool GCToEEInterface::AnalyzeSurvivorsRequested(int condemnedGeneration)
 {
     assert(g_theGCToCLR != nullptr);
diff --git a/src/gc/gchandletable.cpp b/src/gc/gchandletable.cpp
index ad3c6e23c8..ed24c3e53b 100644
--- a/src/gc/gchandletable.cpp
+++ b/src/gc/gchandletable.cpp
@@ -57,18 +57,6 @@ OBJECTHANDLE GCHandleStore::CreateDependentHandle(Object* primary, Object* secon
     return handle;
 }
 
-void GCHandleStore::RelocateAsyncPinnedHandles(IGCHandleStore* pTarget, void (*clearIfComplete)(Object*), void (*setHandle)(Object*, OBJECTHANDLE))
-{
-    // assumption - the IGCHandleStore is an instance of GCHandleStore
-    GCHandleStore* other = static_cast<GCHandleStore*>(pTarget);
-    ::Ref_RelocateAsyncPinHandles(&_underlyingBucket, &other->_underlyingBucket, clearIfComplete, setHandle);
-}
-
-bool GCHandleStore::EnumerateAsyncPinnedHandles(async_pin_enum_fn callback, void* context)
-{
-    return !!::Ref_HandleAsyncPinHandles(callback, context);
-}
-
 GCHandleStore::~GCHandleStore()
 {
     ::Ref_DestroyHandleTableBucket(&_underlyingBucket);
@@ -94,7 +82,7 @@ IGCHandleStore* GCHandleManager::GetGlobalHandleStore()
     return g_gcGlobalHandleStore;
 }
 
-IGCHandleStore* GCHandleManager::CreateHandleStore(void* context)
+IGCHandleStore* GCHandleManager::CreateHandleStore()
 {
 #ifndef FEATURE_REDHAWK
     GCHandleStore* store = new (nothrow) GCHandleStore();
@@ -103,7 +91,7 @@ IGCHandleStore* GCHandleManager::CreateHandleStore(void* context)
         return nullptr;
     }
 
-    bool success = ::Ref_InitializeHandleTableBucket(&store->_underlyingBucket, context);
+    bool success = ::Ref_InitializeHandleTableBucket(&store->_underlyingBucket);
     if (!success)
     {
         delete store;
@@ -122,11 +110,6 @@ void GCHandleManager::DestroyHandleStore(IGCHandleStore* store)
     delete store;
 }
 
-void* GCHandleManager::GetHandleContext(OBJECTHANDLE handle)
-{
-    return (void*)((uintptr_t)::HndGetHandleTableADIndex(::HndGetHandleTable(handle)).m_dwIndex);
-}
-
 OBJECTHANDLE GCHandleManager::CreateGlobalHandleOfType(Object* object, HandleType type)
 {
     return ::HndCreateHandle(g_HandleTableMap.pBuckets[0]->pTable[GetCurrentThreadHomeHeapNumber()], type, ObjectToOBJECTREF(object)); 
diff --git a/src/gc/gchandletableimpl.h b/src/gc/gchandletableimpl.h
index 77af352d4e..48eb2ab17d 100644
--- a/src/gc/gchandletableimpl.h
+++ b/src/gc/gchandletableimpl.h
@@ -23,10 +23,6 @@ public:
 
     virtual OBJECTHANDLE CreateDependentHandle(Object* primary, Object* secondary);
 
-    virtual void RelocateAsyncPinnedHandles(IGCHandleStore* pTarget, void (*clearIfCompleteCallback)(Object* object), void (*setHandle)(Object* object, OBJECTHANDLE handle));
-
-    virtual bool EnumerateAsyncPinnedHandles(async_pin_enum_fn callback, void* context);
-
     virtual ~GCHandleStore();
 
     HandleTableBucket _underlyingBucket;
@@ -41,11 +37,9 @@ public:
 
     virtual void Shutdown();
 
-    virtual void* GetHandleContext(OBJECTHANDLE handle);
-
     virtual IGCHandleStore* GetGlobalHandleStore();
 
-    virtual IGCHandleStore* CreateHandleStore(void* context);
+    virtual IGCHandleStore* CreateHandleStore();
 
     virtual void DestroyHandleStore(IGCHandleStore* store);
 
diff --git a/src/gc/gcimpl.h b/src/gc/gcimpl.h
index 711ecb5fdc..b3aeb36516 100644
--- a/src/gc/gcimpl.h
+++ b/src/gc/gcimpl.h
@@ -208,7 +208,6 @@ public:
     PER_HEAP_ISOLATED size_t GetFinalizablePromotedCount();
 
     void SetFinalizeQueueForShutdown(bool fHasLock);
-    bool FinalizeAppDomain(void *pDomain, bool fRunFinalizers);
     bool ShouldRestartFinalizerWatchDog();
 
     void DiagWalkObject (Object* obj, walk_fn fn, void* context);
diff --git a/src/gc/gcinterface.dac.h b/src/gc/gcinterface.dac.h
index 93698c05a9..44bf00d316 100644
--- a/src/gc/gcinterface.dac.h
+++ b/src/gc/gcinterface.dac.h
@@ -53,15 +53,11 @@ public:
 
 class dac_handle_table {
 public:
-    // On the handle table side, this is an ADIndex. They should still have
-    // the same layout.
-    //
     // We do try to keep everything that the DAC knows about as close to the
     // start of the struct as possible to avoid having padding members. However,
     // HandleTable has rgTypeFlags at offset 0 for performance reasons and
     // we don't want to disrupt that.
     uint32_t padding[HANDLE_MAX_INTERNAL_TYPES];
-    DWORD uADIndex;
 };
 
 class dac_handle_table_bucket {
diff --git a/src/gc/gcinterface.ee.h b/src/gc/gcinterface.ee.h
index 4d12ae9df9..ea9387e2a3 100644
--- a/src/gc/gcinterface.ee.h
+++ b/src/gc/gcinterface.ee.h
@@ -154,9 +154,9 @@ public:
     virtual
     void FireGCFullNotify_V1(uint32_t genNumber, uint32_t isAlloc) = 0;
     virtual
-    void FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID) = 0;
+    void FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation) = 0;
     virtual
-    void FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID) = 0;
+    void FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation) = 0;
     virtual
     void FireDestroyGCHandle(void *handleID) = 0;
     virtual
@@ -321,11 +321,6 @@ public:
     virtual
     void HandleFatalError(unsigned int exitCode) = 0;
 
-    // Asks the EE if it wants a particular object to be finalized when unloading
-    // an app domain.
-    virtual
-    bool ShouldFinalizeObjectForUnload(void* pDomain, Object* obj) = 0;
-
     // Offers the EE the option to finalize the given object eagerly, i.e.
     // not on the finalizer thread but on the current thread. The
     // EE returns true if it finalized the object eagerly and the GC does not
@@ -410,24 +405,9 @@ public:
     IGCToCLREventSink* EventSink() = 0;
 
     virtual
-    uint32_t GetDefaultDomainIndex() = 0;
-
-    virtual
-    void *GetAppDomainAtIndex(uint32_t appDomainIndex) = 0;
-
-    virtual
-    uint32_t GetIndexOfAppDomainBeingUnloaded() = 0;
-
-    virtual
-    bool AppDomainCanAccessHandleTable(uint32_t appDomainID) = 0;
-
-    virtual
     uint32_t GetTotalNumSizedRefHandles() = 0;
 
     virtual
-    bool AppDomainIsRudeUnload(void *appDomain) = 0;
-
-    virtual
     bool AnalyzeSurvivorsRequested(int condemnedGeneration) = 0;
 
     virtual
diff --git a/src/gc/gcinterface.h b/src/gc/gcinterface.h
index 92e7987cbf..083e84fdc6 100644
--- a/src/gc/gcinterface.h
+++ b/src/gc/gcinterface.h
@@ -469,17 +469,6 @@ public:
 
     virtual OBJECTHANDLE CreateDependentHandle(Object* primary, Object* secondary) = 0;
 
-    // Relocates async pinned handles from a condemned handle store to the default domain's handle store.
-    //
-    // The two callbacks are called when:
-    //   1. clearIfComplete is called whenever the handle table observes an async pin that is still live.
-    //      The callback gives a chance for the EE to unpin the referents if the overlapped operation is complete.
-    //   2. setHandle is called whenever the GC has relocated the async pin to a new handle table. The passed-in
-    //      handle is the newly-allocated handle in the default domain that should be assigned to the overlapped object.
-    virtual void RelocateAsyncPinnedHandles(IGCHandleStore* pTarget, void (*clearIfComplete)(Object*), void (*setHandle)(Object*, OBJECTHANDLE)) = 0;
-
-    virtual bool EnumerateAsyncPinnedHandles(async_pin_enum_fn callback, void* context) = 0;
-
     virtual ~IGCHandleStore() {};
 };
 
@@ -490,11 +479,9 @@ public:
 
     virtual void Shutdown() = 0;
 
-    virtual void* GetHandleContext(OBJECTHANDLE handle) = 0;
-
     virtual IGCHandleStore* GetGlobalHandleStore() = 0;
 
-    virtual IGCHandleStore* CreateHandleStore(void* context) = 0;
+    virtual IGCHandleStore* CreateHandleStore() = 0;
 
     virtual void DestroyHandleStore(IGCHandleStore* store) = 0;
 
@@ -555,8 +542,7 @@ public:
     to synchronize with the GC, when the VM wants to update something that
     the GC is potentially using, if it's doing a background GC.
 
-    Concrete examples of this are moving async pinned handles across appdomains
-    and profiling/ETW scenarios.
+    Concrete examples of this are profiling/ETW scenarios.
     ===========================================================================
     */
 
@@ -586,9 +572,6 @@ public:
     ===========================================================================
     */
 
-    // Finalizes an app domain by finalizing objects within that app domain.
-    virtual bool FinalizeAppDomain(void* pDomain, bool fRunFinalizers) = 0;
-
     // Finalizes all registered objects for shutdown, even if they are still reachable.
     virtual void SetFinalizeQueueForShutdown(bool fHasLock) = 0;
 
@@ -663,7 +646,7 @@ public:
 
     // Returns the number of GCs that have transpired in the given generation
     // since the beginning of the life of the process. Also used by the VM
-    // for debug code and app domains.
+    // for debug code.
     virtual int CollectionCount(int generation, int get_bgc_fgc_coutn = 0) = 0;
 
     // Begins a no-GC region, returning a code indicating whether entering the no-GC
@@ -909,7 +892,6 @@ void updateGCShadow(Object** ptr, Object* val);
 
 #define GC_CALL_INTERIOR            0x1
 #define GC_CALL_PINNED              0x2
-#define GC_CALL_CHECK_APP_DOMAIN    0x4
 
 //flags for IGCHeapAlloc(...)
 enum GC_ALLOC_FLAGS
@@ -952,11 +934,7 @@ struct ScanContext
     uintptr_t stack_limit; // Lowest point on the thread stack that the scanning logic is permitted to read
     bool promotion; //TRUE: Promotion, FALSE: Relocation.
     bool concurrent; //TRUE: concurrent scanning 
-#if defined (FEATURE_APPDOMAIN_RESOURCE_MONITORING) || defined (DACCESS_COMPILE)
-    AppDomain *pCurrentDomain;
-#else
     void* _unused1;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING || DACCESS_COMPILE
     void* pMD;
 #if defined(GC_PROFILING) || defined(FEATURE_EVENT_TRACE)
     EtwGCRootKind dwEtwRootKind;
diff --git a/src/gc/gcpriv.h b/src/gc/gcpriv.h
index a4dd54f066..60dcd4236f 100644
--- a/src/gc/gcpriv.h
+++ b/src/gc/gcpriv.h
@@ -3997,10 +3997,6 @@ private:
 
     }
 
-    BOOL FinalizeSegForAppDomain (void *pDomain, 
-                                  BOOL fRunFinalizers, 
-                                  unsigned int Seg);
-
 public:
     ~CFinalize();
     bool Initialize();
@@ -4020,9 +4016,6 @@ public:
     size_t GetNumberFinalizableObjects();
     void DiscardNonCriticalObjects();
 
-    //Methods used by the app domain unloading call to finalize objects in an app domain
-    bool FinalizeAppDomain (void *pDomain, bool fRunFinalizers);
-
     void CheckFinalizerObjects();
 };
 
diff --git a/src/gc/handletable.cpp b/src/gc/handletable.cpp
index 274c6ff0df..221911500c 100644
--- a/src/gc/handletable.cpp
+++ b/src/gc/handletable.cpp
@@ -83,7 +83,7 @@ __inline PTR_HandleTable Table(HHANDLETABLE hTable)
  * Allocates and initializes a handle table.
  *
  */
-HHANDLETABLE HndCreateHandleTable(const uint32_t *pTypeFlags, uint32_t uTypeCount, ADIndex uADIndex)
+HHANDLETABLE HndCreateHandleTable(const uint32_t *pTypeFlags, uint32_t uTypeCount)
 {
     CONTRACTL
     {
@@ -141,7 +141,6 @@ HHANDLETABLE HndCreateHandleTable(const uint32_t *pTypeFlags, uint32_t uTypeCoun
 
     // Store user data
     pTable->uTableIndex = (uint32_t) -1;
-    pTable->uADIndex = uADIndex;
 
     // loop over various arrays an initialize them
     uint32_t u;
@@ -246,38 +245,6 @@ uint32_t HndGetHandleTableIndex(HHANDLETABLE hTable)
     return pTable->uTableIndex;
 }
 
-/*
- * HndGetHandleTableIndex
- *
- * Retrieves the AppDomain index associated with a handle table at creation
- */
-ADIndex HndGetHandleTableADIndex(HHANDLETABLE hTable)
-{
-    WRAPPER_NO_CONTRACT;
-
-    // fetch the handle table pointer
-    HandleTable *pTable = Table(hTable);
-
-    return pTable->uADIndex;
-}
-
-/*
- * HndGetHandleTableIndex
- *
- * Retrieves the AppDomain index associated with a handle table at creation
- */
-GC_DAC_VISIBLE
-ADIndex HndGetHandleADIndex(OBJECTHANDLE handle)
-{
-    WRAPPER_NO_CONTRACT;
-    SUPPORTS_DAC;
-
-    // fetch the handle table pointer
-    HandleTable *pTable = Table(HndGetHandleTable(handle));
-
-    return pTable->uADIndex;
-}
-
 #ifndef DACCESS_COMPILE
 /*
  * HndCreateHandle
@@ -353,7 +320,7 @@ OBJECTHANDLE HndCreateHandle(HHANDLETABLE hTable, uint32_t uType, OBJECTREF obje
 #endif // !DACCESS_COMPILE
 
 #ifdef _DEBUG
-void ValidateFetchObjrefForHandle(OBJECTREF objref, ADIndex appDomainIndex)
+void ValidateFetchObjrefForHandle(OBJECTREF objref)
 {
     STATIC_CONTRACT_NOTHROW;
     STATIC_CONTRACT_GC_NOTRIGGER;
@@ -362,15 +329,10 @@ void ValidateFetchObjrefForHandle(OBJECTREF objref, ADIndex appDomainIndex)
 
     BEGIN_DEBUG_ONLY_CODE;
     VALIDATEOBJECTREF (objref);
-
-#ifndef DACCESS_COMPILE
-    _ASSERTE(GCToEEInterface::AppDomainCanAccessHandleTable(appDomainIndex.m_dwIndex));
-#endif // DACCESS_COMPILE
-
     END_DEBUG_ONLY_CODE;
 }
 
-void ValidateAssignObjrefForHandle(OBJECTREF objref, ADIndex appDomainIndex)
+void ValidateAssignObjrefForHandle(OBJECTREF objref)
 {
     STATIC_CONTRACT_NOTHROW;
     STATIC_CONTRACT_GC_NOTRIGGER;
@@ -378,41 +340,8 @@ void ValidateAssignObjrefForHandle(OBJECTREF objref, ADIndex appDomainIndex)
     STATIC_CONTRACT_DEBUG_ONLY;
 
     BEGIN_DEBUG_ONLY_CODE;
-
     VALIDATEOBJECTREF (objref);
-
-#ifndef DACCESS_COMPILE
-    _ASSERTE(GCToEEInterface::AppDomainCanAccessHandleTable(appDomainIndex.m_dwIndex));
-#endif // DACCESS_COMPILE
-    END_DEBUG_ONLY_CODE;
-}
-
-void ValidateAppDomainForHandle(OBJECTHANDLE handle)
-{
-    STATIC_CONTRACT_DEBUG_ONLY;
-    STATIC_CONTRACT_NOTHROW;
-
-#ifdef DEBUG_DestroyedHandleValue
-    // Verify that we are not trying to access freed handle.
-    _ASSERTE("Attempt to access destroyed handle." && *(_UNCHECKED_OBJECTREF *)handle != DEBUG_DestroyedHandleValue);
-#endif
-#ifdef DACCESS_COMPILE
-    UNREFERENCED_PARAMETER(handle);
-#else
-    BEGIN_DEBUG_ONLY_CODE;
-    ADIndex id = HndGetHandleADIndex(handle);
-    ADIndex unloadingDomain(GCToEEInterface::GetIndexOfAppDomainBeingUnloaded());
-    if (unloadingDomain != id)
-    {
-        return;
-    }
-    if (GCToEEInterface::AppDomainCanAccessHandleTable(unloadingDomain.m_dwIndex))
-    {
-        return;
-    }
-    _ASSERTE (!"Access to a handle in unloaded domain is not allowed");
     END_DEBUG_ONLY_CODE;
-#endif // !DACCESS_COMPILE
 }
 #endif
 
@@ -443,10 +372,6 @@ void HndDestroyHandle(HHANDLETABLE hTable, uint32_t uType, OBJECTHANDLE handle)
     // sanity check handle we are being asked to free
     _ASSERTE(handle);
 
-#ifdef _DEBUG
-    ValidateAppDomainForHandle(handle);
-#endif
-
     // fetch the handle table pointer
     HandleTable *pTable = Table(hTable);
 
@@ -593,35 +518,18 @@ void HndLogSetEvent(OBJECTHANDLE handle, _UNCHECKED_OBJECTREF value)
     if (EVENT_ENABLED(SetGCHandle) || EVENT_ENABLED(PrvSetGCHandle))
     {
         uint32_t hndType = HandleFetchType(handle);
-        ADIndex appDomainIndex = HndGetHandleADIndex(handle);   
-        void* pAppDomain = GCToEEInterface::GetAppDomainAtIndex(appDomainIndex.m_dwIndex);
         uint32_t generation = value != 0 ? g_theGCHeap->WhichGeneration(value) : 0;
-        FIRE_EVENT(SetGCHandle, (void *)handle, (void *)value, hndType, generation, (uint64_t)pAppDomain);
-        FIRE_EVENT(PrvSetGCHandle, (void *) handle, (void *)value, hndType, generation, (uint64_t)pAppDomain);
+        FIRE_EVENT(SetGCHandle, (void *)handle, (void *)value, hndType, generation);
+        FIRE_EVENT(PrvSetGCHandle, (void *) handle, (void *)value, hndType, generation);
 
         // Also fire the things pinned by Async pinned handles
         if (hndType == HNDTYPE_ASYNCPINNED)
         {
-            // the closure passed to "WalkOverlappedObject" is not permitted to implicitly
-            // capture any variables in this scope, since WalkForOverlappedObject takes a bare
-            // function pointer and context pointer as arguments. We can still /explicitly/
-            // close over values in this scope by doing what the compiler would do and introduce
-            // a structure that contains all of the things we closed over, while passing a pointer
-            // to this structure as our closure's context pointer.
-            struct ClosureCapture
+            GCToEEInterface::WalkAsyncPinned(value, value, [](Object*, Object* to, void* ctx)
             {
-                void* pAppDomain;
-                Object* overlapped;
-            };
-
-            ClosureCapture captured;
-            captured.pAppDomain = pAppDomain;
-            captured.overlapped = value;
-            GCToEEInterface::WalkAsyncPinned(value, &captured, [](Object*, Object* to, void* ctx)
-            {
-                ClosureCapture* captured = reinterpret_cast<ClosureCapture*>(ctx);
+                Object* overlapped = reinterpret_cast<Object*>(ctx);
                 uint32_t generation = to != nullptr ? g_theGCHeap->WhichGeneration(to) : 0;
-                FIRE_EVENT(SetGCHandle, (void *)captured->overlapped, (void *)to, HNDTYPE_PINNED, generation, (uint64_t)captured->pAppDomain);
+                FIRE_EVENT(SetGCHandle, (void *)overlapped, (void *)to, HNDTYPE_PINNED, generation);
             });
         }
     }
@@ -1130,49 +1038,6 @@ uint32_t HndCountAllHandles(BOOL fUseLocks)
     return uCount;
 }
 
-BOOL  Ref_HandleAsyncPinHandles(async_pin_enum_fn asyncPinCallback, void* context)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-    }
-    CONTRACTL_END;
-
-    AsyncPinCallbackContext callbackCtx(asyncPinCallback, context);
-    HandleTableBucket *pBucket = g_HandleTableMap.pBuckets[0];
-    BOOL result = FALSE;
-    int limit = getNumberOfSlots();
-    for (int n = 0; n < limit; n ++ )
-    {
-        if (TableHandleAsyncPinHandles(Table(pBucket->pTable[n]), callbackCtx))
-        {
-            result = TRUE;
-        }
-    }
-
-    return result;
-}
-
-void  Ref_RelocateAsyncPinHandles(HandleTableBucket *pSource,
-    HandleTableBucket *pTarget,
-    void (*clearIfComplete)(Object* object),
-    void (*setHandle)(Object* object, OBJECTHANDLE handle))
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_TRIGGERS;
-    }
-    CONTRACTL_END;
-
-    int limit = getNumberOfSlots();
-    for (int n = 0; n < limit; n ++ )
-    {
-        TableRelocateAsyncPinHandles(Table(pSource->pTable[n]), Table(pTarget->pTable[n]), clearIfComplete, setHandle);
-    }
-}
-
 /*--------------------------------------------------------------------------*/
 
 
diff --git a/src/gc/handletable.h b/src/gc/handletable.h
index 70959edf3b..7cadcf92c4 100644
--- a/src/gc/handletable.h
+++ b/src/gc/handletable.h
@@ -53,7 +53,7 @@ typedef PTR_PTR_HandleTable PTR_HHANDLETABLE;
 /*
  * handle manager init and shutdown routines
  */
-HHANDLETABLE    HndCreateHandleTable(const uint32_t *pTypeFlags, uint32_t uTypeCount, ADIndex uADIndex);
+HHANDLETABLE    HndCreateHandleTable(const uint32_t *pTypeFlags, uint32_t uTypeCount);
 void            HndDestroyHandleTable(HHANDLETABLE hTable);
 #endif // !DACCESS_COMPILE
 
@@ -62,10 +62,6 @@ void            HndDestroyHandleTable(HHANDLETABLE hTable);
  */
 void            HndSetHandleTableIndex(HHANDLETABLE hTable, uint32_t uTableIndex);
 uint32_t        HndGetHandleTableIndex(HHANDLETABLE hTable);
-ADIndex         HndGetHandleTableADIndex(HHANDLETABLE hTable);
-
-GC_DAC_VISIBLE
-ADIndex         HndGetHandleADIndex(OBJECTHANDLE handle);
 
 #ifndef DACCESS_COMPILE
 /*
@@ -143,9 +139,8 @@ uint32_t        HndCountAllHandles(BOOL fUseLocks);
 
 
 #ifdef _DEBUG_IMPL
-void ValidateAssignObjrefForHandle(OBJECTREF, ADIndex appDomainIndex);
-void ValidateFetchObjrefForHandle(OBJECTREF, ADIndex appDomainIndex);
-void ValidateAppDomainForHandle(OBJECTHANDLE handle);
+void ValidateAssignObjrefForHandle(OBJECTREF);
+void ValidateFetchObjrefForHandle(OBJECTREF);
 #endif
 
 /*
@@ -185,8 +180,7 @@ OBJECTREF HndFetchHandle(OBJECTHANDLE handle)
     _ASSERTE("Attempt to access destroyed handle." && *(_UNCHECKED_OBJECTREF *)handle != DEBUG_DestroyedHandleValue);
 
     // Make sure the objref for handle is valid
-    ValidateFetchObjrefForHandle(ObjectToOBJECTREF(*(Object **)handle), 
-                            HndGetHandleTableADIndex(HndGetHandleTable(handle)));
+    ValidateFetchObjrefForHandle(ObjectToOBJECTREF(*(Object **)handle));
 #endif // _DEBUG_IMPL
 
     // wrap the raw objectref and return it
diff --git a/src/gc/handletablecore.cpp b/src/gc/handletablecore.cpp
index 5fc661c000..ee2d8873a8 100644
--- a/src/gc/handletablecore.cpp
+++ b/src/gc/handletablecore.cpp
@@ -616,550 +616,6 @@ TableSegment *SegmentAlloc(HandleTable *pTable)
     return pSegment;
 }
 
-// Mark a handle being free.
-__inline void SegmentMarkFreeMask(TableSegment *pSegment, _UNCHECKED_OBJECTREF* h)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-    
-    uint32_t uMask = (uint32_t)(h - pSegment->rgValue);
-    uint32_t uBit = uMask % HANDLE_HANDLES_PER_MASK;
-    uMask = uMask / HANDLE_HANDLES_PER_MASK;
-    pSegment->rgFreeMask[uMask] |= (1<<uBit);
-}
-
-// Mark a handle being used.
-__inline void SegmentUnMarkFreeMask(TableSegment *pSegment, _UNCHECKED_OBJECTREF* h)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-    
-    uint32_t uMask = (uint32_t)(h - pSegment->rgValue);
-    uint32_t uBit = uMask % HANDLE_HANDLES_PER_MASK;
-    uMask = uMask / HANDLE_HANDLES_PER_MASK;
-    pSegment->rgFreeMask[uMask] &= ~(1<<uBit);
-}
-
-// Prepare a segment to be moved to default domain.
-// Remove all non-async pin handles.
-void SegmentPreCompactAsyncPinHandles(TableSegment *pSegment, void (*clearIfComplete)(Object*))
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-
-    pSegment->fResortChains = true;
-    pSegment->fNeedsScavenging = true;
-    
-    // Zero out all non-async pin handles
-    uint32_t uBlock;
-    for (uBlock = 0; uBlock < pSegment->bEmptyLine; uBlock ++)
-    {
-        if (pSegment->rgBlockType[uBlock]  == TYPE_INVALID)
-        {
-            continue;
-        }
-        else if (pSegment->rgBlockType[uBlock] != HNDTYPE_ASYNCPINNED)
-        {
-            _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-            _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-            do
-            {
-                *pValue = NULL;
-                pValue ++;
-            } while (pValue < pLast);
-
-            ((uint32_t*)pSegment->rgGeneration)[uBlock] = (uint32_t)-1;
-
-            uint32_t *pdwMask = pSegment->rgFreeMask + (uBlock * HANDLE_MASKS_PER_BLOCK);
-            uint32_t *pdwMaskLast = pdwMask + HANDLE_MASKS_PER_BLOCK;
-            do
-            {
-                *pdwMask = MASK_EMPTY;
-                pdwMask ++;
-            } while (pdwMask < pdwMaskLast);
-
-            pSegment->rgBlockType[uBlock] = TYPE_INVALID;
-            pSegment->rgUserData[uBlock] = BLOCK_INVALID;
-            pSegment->rgLocks[uBlock] = 0;
-        }
-    }
-
-    // Return all non-async pin handles to free list
-    uint32_t uType;
-    for (uType = 0; uType < HANDLE_MAX_INTERNAL_TYPES; uType ++)
-    {
-        if (uType == HNDTYPE_ASYNCPINNED)
-        {
-            continue;
-        }
-        pSegment->rgFreeCount[uType] = 0;
-        if (pSegment->rgHint[uType] != BLOCK_INVALID)
-        {
-            uint32_t uLast = pSegment->rgHint[uType];
-            uint8_t uFirst = pSegment->rgAllocation[uLast];
-            pSegment->rgAllocation[uLast] = pSegment->bFreeList;
-            pSegment->bFreeList = uFirst;
-            pSegment->rgHint[uType] = BLOCK_INVALID;
-            pSegment->rgTail[uType] = BLOCK_INVALID;
-        }
-    }
-
-    // make sure the remaining async handle has MethodTable that exists in default domain
-    uBlock = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-    if (uBlock == BLOCK_INVALID)
-    {
-        return;
-    }
-    uint32_t freeCount = 0;
-    for (uBlock = 0; uBlock < pSegment->bEmptyLine; uBlock ++)
-    {
-        if (pSegment->rgBlockType[uBlock] != HNDTYPE_ASYNCPINNED)
-        {
-            continue;
-        }
-        if (pSegment->rgFreeMask[uBlock*2] == (uint32_t)-1 && pSegment->rgFreeMask[uBlock*2+1] == (uint32_t)-1)
-        {
-            continue;
-        }
-        _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-        _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-        
-        do
-        {
-            _UNCHECKED_OBJECTREF value = *pValue;
-            if (!HndIsNullOrDestroyedHandle(value))
-            {
-                clearIfComplete((Object*)value);
-            }
-            else
-            {
-                // reset free mask
-                SegmentMarkFreeMask(pSegment, pValue);
-                freeCount ++;
-            }
-            pValue ++;
-        } while (pValue != pLast);
-    }
-
-    pSegment->rgFreeCount[HNDTYPE_ASYNCPINNED] = freeCount;
-}
-
-// Copy a handle to a different segment in the same HandleTable
-BOOL SegmentCopyAsyncPinHandle(TableSegment *pSegment, _UNCHECKED_OBJECTREF *h)
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-
-    _ASSERTE (HandleFetchSegmentPointer((OBJECTHANDLE)h) != pSegment);
-
-    if (pSegment->rgFreeCount[HNDTYPE_ASYNCPINNED] == 0)
-    {
-        uint8_t uBlock = pSegment->bFreeList;
-        if (uBlock == BLOCK_INVALID)
-        {
-            // All slots are used up.
-            return FALSE;
-        }
-        pSegment->bFreeList = pSegment->rgAllocation[uBlock];
-        pSegment->rgBlockType[uBlock] = HNDTYPE_ASYNCPINNED;
-        pSegment->rgAllocation[uBlock] = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-        pSegment->rgHint[HNDTYPE_ASYNCPINNED] = uBlock;
-        pSegment->rgFreeCount[HNDTYPE_ASYNCPINNED] += HANDLE_HANDLES_PER_BLOCK;
-    }
-    uint8_t uBlock = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-    uint8_t uLast = uBlock;
-    do
-    {
-        uint32_t n = uBlock * (HANDLE_HANDLES_PER_BLOCK/HANDLE_HANDLES_PER_MASK);
-        uint32_t* pMask = pSegment->rgFreeMask + n;
-        if (pMask[0] != 0 || pMask[1] != 0)
-        {
-            break;
-        }
-        uBlock = pSegment->rgAllocation[uBlock];
-    } while (uBlock != uLast);
-    _ASSERTE (uBlock != uLast);
-    pSegment->rgHint[HNDTYPE_ASYNCPINNED] = uBlock;
-    _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-    _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-    do
-    {
-        if (*pValue == NULL)
-        {
-            SegmentUnMarkFreeMask(pSegment,pValue);
-            *pValue = *h;
-            *h = NULL;
-            break;
-        }
-        pValue ++;
-    } while (pValue != pLast);
-    _ASSERTE (pValue != pLast);
-    pSegment->rgFreeCount[HNDTYPE_ASYNCPINNED] --;
-    return TRUE;
-}
-
-void SegmentCompactAsyncPinHandles(TableSegment *pSegment, TableSegment **ppWorkerSegment, void (*clearIfComplete)(Object*))
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-
-    uint32_t uBlock = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-    if (uBlock == BLOCK_INVALID)
-    {
-        return;
-    }
-    for (uBlock = 0; uBlock < pSegment->bEmptyLine; uBlock ++)
-    {
-        if (pSegment->rgBlockType[uBlock] != HNDTYPE_ASYNCPINNED)
-        {
-            continue;
-        }
-        if (pSegment->rgFreeMask[uBlock*2] == (uint32_t)-1 && pSegment->rgFreeMask[uBlock*2+1] == (uint32_t)-1)
-        {
-            continue;
-        }
-        _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-        _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-
-        do
-        {
-            BOOL fNeedNewSegment = FALSE;
-            _UNCHECKED_OBJECTREF value = *pValue;
-            if (!HndIsNullOrDestroyedHandle(value))
-            {
-                clearIfComplete((Object*)value);
-                fNeedNewSegment = !SegmentCopyAsyncPinHandle(*ppWorkerSegment,pValue);
-            }
-            if (fNeedNewSegment)
-            {
-                _ASSERTE ((*ppWorkerSegment)->rgFreeCount[HNDTYPE_ASYNCPINNED] == 0 &&
-                          (*ppWorkerSegment)->bFreeList == BLOCK_INVALID);
-                TableSegment *pNextSegment = (*ppWorkerSegment)->pNextSegment;
-                SegmentPreCompactAsyncPinHandles(pNextSegment, clearIfComplete);
-                *ppWorkerSegment = pNextSegment;
-                if (pNextSegment == pSegment)
-                {
-                    // The current segment will be moved to default domain.
-                    return;
-                }
-            }
-            else
-            {
-                pValue ++;
-            }
-        } while (pValue != pLast);
-    }
-}
-
-
-// Mark AsyncPinHandles ready to be cleaned when the marker job is processed
-BOOL SegmentHandleAsyncPinHandles (TableSegment *pSegment, const AsyncPinCallbackContext &callbackCtx)
-{
-    CONTRACTL
-    {
-        GC_NOTRIGGER;
-        NOTHROW;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-    
-    uint32_t uBlock = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-    if (uBlock == BLOCK_INVALID)
-    {
-        // There is no pinning handles.
-        return FALSE;
-    }
-
-    BOOL result = FALSE;
-
-    for (uBlock = 0; uBlock < pSegment->bEmptyLine; uBlock ++)
-    {
-        if (pSegment->rgBlockType[uBlock] != HNDTYPE_ASYNCPINNED)
-        {
-            continue;
-        }
-        if (pSegment->rgFreeMask[uBlock*2] == (uint32_t)-1 && pSegment->rgFreeMask[uBlock*2+1] == (uint32_t)-1)
-        {
-            continue;
-        }
-        _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-        _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-
-        do
-        {
-            _UNCHECKED_OBJECTREF value = *pValue;
-            if (!HndIsNullOrDestroyedHandle(value))
-            {
-                // calls back into the VM using the callback given to
-                // Ref_HandleAsyncPinHandles
-                if (callbackCtx.Invoke((Object*)value))
-                {
-                    result = TRUE;
-                }
-            }
-            pValue ++;
-        } while (pValue != pLast);
-    }
-
-    return result;
-}
-
-// Replace an async pin handle with one from default domain
-bool SegmentRelocateAsyncPinHandles (TableSegment *pSegment,
-    HandleTable *pTargetTable,
-    void (*clearIfComplete)(Object*),
-    void (*setHandle)(Object*, OBJECTHANDLE))
-{
-    CONTRACTL
-    {
-        GC_NOTRIGGER;
-        NOTHROW;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-    
-    uint32_t uBlock = pSegment->rgHint[HNDTYPE_ASYNCPINNED];
-    if (uBlock == BLOCK_INVALID)
-    {
-        // There is no pinning handles.
-        return true;
-    }
-    for (uBlock = 0; uBlock < pSegment->bEmptyLine; uBlock ++)
-    {
-        if (pSegment->rgBlockType[uBlock] != HNDTYPE_ASYNCPINNED)
-        {
-            continue;
-        }
-        if (pSegment->rgFreeMask[uBlock*2] == (uint32_t)-1 && pSegment->rgFreeMask[uBlock*2+1] == (uint32_t)-1)
-        {
-            continue;
-        }
-        _UNCHECKED_OBJECTREF *pValue = pSegment->rgValue + (uBlock * HANDLE_HANDLES_PER_BLOCK);
-        _UNCHECKED_OBJECTREF *pLast = pValue + HANDLE_HANDLES_PER_BLOCK;
-
-        do
-        {
-            _UNCHECKED_OBJECTREF value = *pValue;
-            if (!HndIsNullOrDestroyedHandle(value))
-            {
-                clearIfComplete((Object*)value);
-                OBJECTHANDLE selfHandle = HndCreateHandle((HHANDLETABLE)pTargetTable, HNDTYPE_ASYNCPINNED, ObjectToOBJECTREF(value));
-                if (!selfHandle)
-                {
-                    // failed to allocate a new handle - callers have to handle this.
-                    return false;
-                }
-
-                setHandle((Object*)value, selfHandle);
-                *pValue = NULL;
-            }
-            pValue ++;
-        } while (pValue != pLast);
-    }
-
-    return true;
-}
-
-// Mark all non-pending AsyncPinHandle ready for cleanup.
-// We will queue a marker Overlapped to io completion port.  We use the marker
-// to make sure that all iocompletion jobs before this marker have been processed.
-// After that we can free the async pinned handles.
-BOOL TableHandleAsyncPinHandles(HandleTable *pTable, const AsyncPinCallbackContext &callbackCtx)
-{
-    CONTRACTL
-    {
-        GC_NOTRIGGER;
-        NOTHROW;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-
-    BOOL result = FALSE;
-    TableSegment *pSegment = pTable->pSegmentList;
-
-    CrstHolder ch(&pTable->Lock);
-
-    while (pSegment)
-    {
-        if (SegmentHandleAsyncPinHandles (pSegment, callbackCtx))
-        {
-            result = TRUE;
-        }
-        pSegment = pSegment->pNextSegment;
-    }
-
-    return result;
-}
-
-// Keep needed async Pin Handle by moving them to default domain.
-// Strategy:
-// 1. Try to create pin handles in default domain to replace it.
-// 2. If 1 failed due to OOM, we will relocate segments from this HandleTable to default domain.
-//    a. Clean the segment so that only saved pin handles exist.  This segment becomes the worker segment.
-//    b. Copy pin handles from remaining segments to the worker segment.  If worker segment is full, start
-//       from a again.
-//    c. After copying all handles to worker segments, move the segments to default domain.
-// It is very important that in step 2, we should not fail for OOM, which means no memory allocation.
-void TableRelocateAsyncPinHandles(HandleTable *pTable,
-    HandleTable *pTargetTable,
-    void (*clearIfComplete)(Object*),
-    void (*setHandle)(Object*, OBJECTHANDLE))
-{
-    CONTRACTL
-    {
-        GC_TRIGGERS;
-        NOTHROW;
-        MODE_COOPERATIVE;
-    }
-    CONTRACTL_END;
-
-    _ASSERTE (pTargetTable->uADIndex == ADIndex(GCToEEInterface::GetDefaultDomainIndex()));  // must be for default domain
-
-    BOOL fGotException = FALSE;
-    TableSegment *pSegment = pTable->pSegmentList;
-    bool wasSuccessful = true;
-    
-#ifdef _DEBUG
-    // on debug builds, execute the OOM path 10% of the time.
-    if (GetRandomInt(100) < 10)
-        goto SLOW_PATH;
-#endif
-
-    // Step 1: replace pinning handles with ones from default domain
-    while (pSegment)
-    {
-        wasSuccessful = wasSuccessful && SegmentRelocateAsyncPinHandles (pSegment, pTargetTable, clearIfComplete, setHandle);
-        if (!wasSuccessful)
-        {
-            break;
-        }
-
-        pSegment = pSegment->pNextSegment;
-    }
-
-    if (wasSuccessful)
-    {
-        return;
-    }
-
-#ifdef _DEBUG
-SLOW_PATH:
-#endif
-
-    // step 2: default domain runs out of space
-    //         compact all remaining pinning handles and move the segments to default domain
-
-    while (true)
-    {
-        CrstHolderWithState ch(&pTable->Lock);
-
-        // We cannot move segments to a different table if we're asynchronously scanning the current table as
-        // part of a concurrent GC. That's because the async table scanning code does most of its work without
-        // the table lock held. So we'll take the table lock and then look to see if we're in a concurrent GC.
-        // If we are we'll back out and try again. This doesn't prevent a concurrent GC from initiating while
-        // we have the lock held but the part we care about (the async table scan) takes the table lock during
-        // a preparation step so we'll be able to complete our segment moves before the async scan has a
-        // chance to interfere with us (or vice versa).
-        if (g_theGCHeap->IsConcurrentGCInProgress())
-        {
-            // A concurrent GC is in progress so someone might be scanning our segments asynchronously.
-            // Release the lock, wait for the GC to complete and try again. The order is important; if we wait
-            // before releasing the table lock we can deadlock with an async table scan.
-            ch.Release();
-            g_theGCHeap->WaitUntilConcurrentGCComplete();
-            continue;
-        }
-
-        // If we get here then we managed to acquire the table lock and observe that no concurrent GC was in
-        // progress. A concurrent GC could start at any time so that state may have changed, but since we took
-        // the table lock first we know that the GC could only have gotten as far as attempting to initiate an
-        // async handle table scan (which attempts to acquire the table lock). So as long as we complete our
-        // segment compaction and moves without releasing the table lock we're guaranteed to complete before
-        // the async scan can get in and observe any of the segments.
-
-        // Compact async pinning handles into the smallest number of leading segments we can (the worker
-        // segments).
-        TableSegment *pWorkerSegment = pTable->pSegmentList;
-        SegmentPreCompactAsyncPinHandles (pWorkerSegment, clearIfComplete);
-
-        pSegment = pWorkerSegment->pNextSegment;
-        while (pSegment)
-        {
-            SegmentCompactAsyncPinHandles (pSegment, &pWorkerSegment, clearIfComplete);
-            pSegment= pSegment->pNextSegment;
-        }
-
-        // Empty the remaining segments.
-        pSegment = pWorkerSegment->pNextSegment;
-        while (pSegment)
-        {
-            memset(pSegment->rgValue, 0, (uint32_t)pSegment->bCommitLine * HANDLE_BYTES_PER_BLOCK);
-            pSegment = pSegment->pNextSegment;
-        }
-
-        // Move the worker segments over to the tail end of the default domain's segment list.
-        {
-            CrstHolder ch1(&pTargetTable->Lock);
-
-            // Locate the segment currently at the tail of the default domain's segment list.
-            TableSegment *pTargetSegment = pTargetTable->pSegmentList;
-            while (pTargetSegment->pNextSegment)
-            {
-                pTargetSegment = pTargetSegment->pNextSegment;
-            }
-
-            // Take the worker segments and point them to their new handle table and recalculate their
-            // sequence numbers to be consistent with the queue they're moving to.
-            uint8_t bLastSequence = pTargetSegment->bSequence;
-            pSegment = pTable->pSegmentList;
-            while (pSegment != pWorkerSegment->pNextSegment)
-            {
-                pSegment->pHandleTable = pTargetTable;
-                pSegment->bSequence = (uint8_t)(((uint32_t)bLastSequence + 1) % 0x100);
-                bLastSequence = pSegment->bSequence;
-                pSegment = pSegment->pNextSegment;
-            }
-
-            // Join the worker segments to the tail of the default domain segment list.
-            pTargetSegment->pNextSegment = pTable->pSegmentList;
-
-            // Reset the current handle table segment list to omit the removed worker segments and start at
-            // the first non-worker.
-            pTable->pSegmentList = pWorkerSegment->pNextSegment;
-
-            // The last worker segment is now the end of the default domain's segment list.
-            pWorkerSegment->pNextSegment = NULL;
-        }
-
-        break;
-    }
-}
-
 /*
  * Check if a handle is part of a HandleTable
  */
diff --git a/src/gc/handletablepriv.h b/src/gc/handletablepriv.h
index e0ed4b80e3..c696431f77 100644
--- a/src/gc/handletablepriv.h
+++ b/src/gc/handletablepriv.h
@@ -338,38 +338,6 @@ struct HandleTypeCache
     int32_t lFreeIndex;
 };
 
-/*
- * Async pin EE callback context, used to call back tot he EE when enumerating
- * over async pinned handles.
- */
-class AsyncPinCallbackContext
-{
-private:
-    async_pin_enum_fn m_callback;
-    void* m_context;
-
-public:
-    /*
-     * Constructs a new AsyncPinCallbackContext from a callback and a context,
-     * which will be passed to the callback as its second parameter every time
-     * it is invoked.
-     */
-    AsyncPinCallbackContext(async_pin_enum_fn callback, void* context)
-        : m_callback(callback), m_context(context)
-    {}
-
-    /*
-     * Invokes the callback with the given argument, returning the callback's
-     * result.'
-     */
-    bool Invoke(Object* argument) const
-    {
-        assert(m_callback != nullptr);
-        return m_callback(argument, m_context);
-    }
-};
-
-
 /*---------------------------------------------------------------------------*/
 
 
@@ -510,11 +478,6 @@ struct HandleTable
     uint32_t rgTypeFlags[HANDLE_MAX_INTERNAL_TYPES];
 
     /*
-     * per-table AppDomain info
-     */
-    ADIndex uADIndex;
-
-    /*
      * lock for this table
      */
     CrstStatic Lock;
@@ -782,22 +745,6 @@ TableSegment *SegmentAlloc(HandleTable *pTable);
 void SegmentFree(TableSegment *pSegment);
 
 /*
- * TableHandleAsyncPinHandles
- *
- * Mark ready for all non-pending OverlappedData that get moved to default domain.
- *
- */
-BOOL TableHandleAsyncPinHandles(HandleTable *pTable, const AsyncPinCallbackContext& callbackCtx);
-
-/*
- * TableRelocateAsyncPinHandles
- *
- * Replaces async pin handles with ones in default domain.
- *
- */
-void TableRelocateAsyncPinHandles(HandleTable *pTable, HandleTable *pTargetTable, void (*clearIfComplete)(Object*), void (*setHandle)(Object*, OBJECTHANDLE));
-
-/*
  * Check if a handle is part of a HandleTable
  */
 BOOL TableContainHandle(HandleTable *pTable, OBJECTHANDLE handle);
diff --git a/src/gc/objecthandle.cpp b/src/gc/objecthandle.cpp
index aa1ab57a51..aad2f0607c 100644
--- a/src/gc/objecthandle.cpp
+++ b/src/gc/objecthandle.cpp
@@ -623,7 +623,7 @@ bool Ref_Initialize()
         n_slots * sizeof(HHANDLETABLE));
     for (int uCPUindex = 0; uCPUindex < n_slots; uCPUindex++)
     {
-        pBucket->pTable[uCPUindex] = HndCreateHandleTable(s_rgTypeFlags, _countof(s_rgTypeFlags), ADIndex(1));
+        pBucket->pTable[uCPUindex] = HndCreateHandleTable(s_rgTypeFlags, _countof(s_rgTypeFlags));
         if (pBucket->pTable[uCPUindex] == NULL)
             goto CleanupAndFail;
 
@@ -688,7 +688,7 @@ void Ref_Shutdown()
 }
 
 #ifndef FEATURE_REDHAWK
-bool Ref_InitializeHandleTableBucket(HandleTableBucket* bucket, void* context)
+bool Ref_InitializeHandleTableBucket(HandleTableBucket* bucket)
 {
     CONTRACTL
     {
@@ -720,7 +720,7 @@ bool Ref_InitializeHandleTableBucket(HandleTableBucket* bucket, void* context)
     ZeroMemory(result->pTable, n_slots * sizeof(HHANDLETABLE));
 
     for (int uCPUindex=0; uCPUindex < n_slots; uCPUindex++) {
-        result->pTable[uCPUindex] = HndCreateHandleTable(s_rgTypeFlags, _countof(s_rgTypeFlags), ADIndex((DWORD)(uintptr_t)context));
+        result->pTable[uCPUindex] = HndCreateHandleTable(s_rgTypeFlags, _countof(s_rgTypeFlags));
         if (!result->pTable[uCPUindex])
             return false;
     }
@@ -863,11 +863,8 @@ void SetDependentHandleSecondary(OBJECTHANDLE handle, OBJECTREF objref)
     _ASSERTE(handle);
 
 #ifdef _DEBUG
-    // handle should not be in unloaded domain
-    ValidateAppDomainForHandle(handle);
-
     // Make sure the objref is valid before it is assigned to a handle
-    ValidateAssignObjrefForHandle(objref, HndGetHandleTableADIndex(HndGetHandleTable(handle)));
+    ValidateAssignObjrefForHandle(objref);
 #endif
     // unwrap the objectref we were given
     _UNCHECKED_OBJECTREF value = OBJECTREF_TO_UNCHECKED_OBJECTREF(objref);
@@ -967,13 +964,6 @@ void TraceVariableHandles(HANDLESCANPROC pfnTrace, uintptr_t lp1, uintptr_t lp2,
                 HHANDLETABLE hTable = walk->pBuckets[i]->pTable[getSlotNumber((ScanContext*) lp1)];
                 if (hTable)
                 {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                    if (g_fEnableARM)
-                    {
-                        ScanContext* sc = (ScanContext *)lp1;
-                        sc->pCurrentDomain = SystemDomain::GetAppDomainAtIndex(HndGetHandleTableADIndex(hTable));
-                    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
                     HndScanHandlesForGC(hTable, VariableTraceDispatcher,
                                         lp1, (uintptr_t)&info, &type, 1, condemned, maxgen, HNDGCF_EXTRAINFO | flags);
                 }
@@ -1032,13 +1022,6 @@ void Ref_TracePinningRoots(uint32_t condemned, uint32_t maxgen, ScanContext* sc,
                 HHANDLETABLE hTable = walk->pBuckets[i]->pTable[getSlotNumber((ScanContext*) sc)];
                 if (hTable)
                 {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                    if (g_fEnableARM)
-                    {
-                        sc->pCurrentDomain = SystemDomain::GetAppDomainAtIndex(HndGetHandleTableADIndex(hTable));
-                    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
                     // Pinned handles and async pinned handles are scanned in separate passes, since async pinned
                     // handles may require a callback into the EE in order to fully trace an async pinned
                     // object's object graph.
@@ -1074,13 +1057,6 @@ void Ref_TraceNormalRoots(uint32_t condemned, uint32_t maxgen, ScanContext* sc,
                 HHANDLETABLE hTable = walk->pBuckets[i]->pTable[getSlotNumber(sc)];
                 if (hTable)
                 {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                    if (g_fEnableARM)
-                    {
-                        sc->pCurrentDomain = SystemDomain::GetAppDomainAtIndex(HndGetHandleTableADIndex(hTable));
-                    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
                     HndScanHandlesForGC(hTable, PromoteObject, uintptr_t(sc), uintptr_t(fn), types, uTypeCount, condemned, maxgen, flags);
                 }
             }
@@ -1360,48 +1336,6 @@ void TraceDependentHandlesBySingleThread(HANDLESCANPROC pfnTrace, uintptr_t lp1,
     }
 }
 
-// We scan handle tables by their buckets (ie, AD index). We could get into the situation where
-// the AD indices are not very compacted (for example if we have just unloaded ADs and their 
-// indices haven't been reused yet) and we could be scanning them in an unbalanced fashion. 
-// Consider using an array to represent the compacted form of all AD indices exist for the 
-// sized ref handles. 
-void ScanSizedRefByAD(uint32_t maxgen, HANDLESCANPROC scanProc, ScanContext* sc, Ref_promote_func* fn, uint32_t flags)
-{
-    HandleTableMap *walk = &g_HandleTableMap;
-    uint32_t type = HNDTYPE_SIZEDREF;
-    int uCPUindex = getSlotNumber(sc);
-    int n_slots = g_theGCHeap->GetNumberOfHeaps();
-
-    while (walk)
-    {
-        for (uint32_t i = 0; i < INITIAL_HANDLE_TABLE_ARRAY_SIZE; i ++)
-        {
-            if (walk->pBuckets[i] != NULL)
-            {
-                ADIndex adIndex = HndGetHandleTableADIndex(walk->pBuckets[i]->pTable[0]);
-                if ((adIndex.m_dwIndex % n_slots) == (uint32_t)uCPUindex)
-                {
-                    for (int index = 0; index < n_slots; index++)
-                    {
-                        HHANDLETABLE hTable = walk->pBuckets[i]->pTable[index];
-                        if (hTable)
-                        {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                            if (g_fEnableARM)
-                            {
-                                sc->pCurrentDomain = SystemDomain::GetAppDomainAtIndex(adIndex);
-                            }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                            HndScanHandlesForGC(hTable, scanProc, uintptr_t(sc), uintptr_t(fn), &type, 1, maxgen, maxgen, flags);
-                        }
-                    }
-                }
-            }
-        }
-        walk = walk->pNext;
-    }
-}
-
 void ScanSizedRefByCPU(uint32_t maxgen, HANDLESCANPROC scanProc, ScanContext* sc, Ref_promote_func* fn, uint32_t flags)
 {
     HandleTableMap *walk = &g_HandleTableMap;
@@ -1417,13 +1351,6 @@ void ScanSizedRefByCPU(uint32_t maxgen, HANDLESCANPROC scanProc, ScanContext* sc
                 HHANDLETABLE hTable = walk->pBuckets[i]->pTable[uCPUindex];
                 if (hTable)
                 {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-                    if (g_fEnableARM)
-                    {
-                        sc->pCurrentDomain = SystemDomain::GetAppDomainAtIndex(HndGetHandleTableADIndex(hTable));
-                    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
                     HndScanHandlesForGC(hTable, scanProc, uintptr_t(sc), uintptr_t(fn), &type, 1, maxgen, maxgen, flags);
                 }
             }
@@ -1858,7 +1785,6 @@ void PopulateHandleTableDacVars(GcDacVars* gcDacVars)
     static_assert(offsetof(HandleTableMap, dwMaxIndex) == offsetof(dac_handle_table_map, dwMaxIndex), "handle table map DAC layout mismatch");
     static_assert(offsetof(HandleTableBucket, pTable) == offsetof(dac_handle_table_bucket, pTable), "handle table bucket DAC layout mismatch");
     static_assert(offsetof(HandleTableBucket, HandleTableIndex) == offsetof(dac_handle_table_bucket, HandleTableIndex), "handle table bucket DAC layout mismatch");
-    static_assert(offsetof(HandleTable, uADIndex) == offsetof(dac_handle_table, uADIndex), "handle table DAC layout mismatch");
 
 #ifndef DACCESS_COMPILE
     gcDacVars->handle_table_map = reinterpret_cast<dac_handle_table_map*>(&g_HandleTableMap);
diff --git a/src/gc/objecthandle.h b/src/gc/objecthandle.h
index 7c44b34ffd..f1b5656265 100644
--- a/src/gc/objecthandle.h
+++ b/src/gc/objecthandle.h
@@ -78,9 +78,7 @@ int GetCurrentThreadHomeHeapNumber();
  */
 bool Ref_Initialize();
 void Ref_Shutdown();
-bool Ref_InitializeHandleTableBucket(HandleTableBucket* bucket, void* context);
-BOOL Ref_HandleAsyncPinHandles(async_pin_enum_fn callback, void* context);
-void Ref_RelocateAsyncPinHandles(HandleTableBucket *pSource, HandleTableBucket *pTarget, void (*clearIfComplete)(Object*), void (*setHandle)(Object*, OBJECTHANDLE));
+bool Ref_InitializeHandleTableBucket(HandleTableBucket* bucket);
 void Ref_RemoveHandleTableBucket(HandleTableBucket *pBucket);
 void Ref_DestroyHandleTableBucket(HandleTableBucket *pBucket);
 
diff --git a/src/gc/sample/gcenv.ee.cpp b/src/gc/sample/gcenv.ee.cpp
index 973b7f4491..730eb9dd9a 100644
--- a/src/gc/sample/gcenv.ee.cpp
+++ b/src/gc/sample/gcenv.ee.cpp
@@ -280,11 +280,6 @@ void GCToEEInterface::HandleFatalError(unsigned int exitCode)
     abort();
 }
 
-bool GCToEEInterface::ShouldFinalizeObjectForUnload(void* pDomain, Object* obj)
-{
-    return true;
-}
-
 bool GCToEEInterface::EagerFinalized(Object* obj)
 {
     // The sample does not finalize anything eagerly.
@@ -346,36 +341,11 @@ void GCToEEInterface::WalkAsyncPinned(Object* object, void* context, void (*call
 {
 }
 
-uint32_t GCToEEInterface::GetDefaultDomainIndex()
-{
-    return -1;
-}
-
-void *GCToEEInterface::GetAppDomainAtIndex(uint32_t appDomainIndex)
-{
-    return nullptr;
-}
-
-bool GCToEEInterface::AppDomainCanAccessHandleTable(uint32_t appDomainID)
-{
-    return true;
-}
-
-uint32_t GCToEEInterface::GetIndexOfAppDomainBeingUnloaded()
-{
-    return -1;
-}
-
 uint32_t GCToEEInterface::GetTotalNumSizedRefHandles()
 {
     return -1;
 }
 
-bool GCToEEInterface::AppDomainIsRudeUnload(void *appDomain)
-{
-    return false;
-}
-
 inline bool GCToEEInterface::AnalyzeSurvivorsRequested(int condemnedGeneration)
 {
     return false;
diff --git a/src/inc/clrconfigvalues.h b/src/inc/clrconfigvalues.h
index cc96d9fdd3..4967278fb9 100644
--- a/src/inc/clrconfigvalues.h
+++ b/src/inc/clrconfigvalues.h
@@ -111,11 +111,6 @@ CONFIG_DWORD_INFO(INTERNAL_ADTakeSnapShot, W("ADTakeSnapShot"), 0, "Superseded b
 CONFIG_DWORD_INFO_DIRECT_ACCESS(INTERNAL_EnableFullDebug, W("EnableFullDebug"), "Heavy-weight checking for AD boundary violations (AD leaks)")
 
 ///
-/// ARM
-///
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_ARMEnabled, W("ARMEnabled"), (DWORD)0, "AppDomain Resource Monitoring. Set to 1 to enable it")
-
-///
 /// Jit Pitching
 ///
 RETAIL_CONFIG_DWORD_INFO(INTERNAL_JitPitchEnabled, W("JitPitchEnabled"), (DWORD)0, "Set it to 1 to enable Jit Pitching")
diff --git a/src/vm/appdomain.cpp b/src/vm/appdomain.cpp
index ed6d05fc87..2d92d3f952 100644
--- a/src/vm/appdomain.cpp
+++ b/src/vm/appdomain.cpp
@@ -115,10 +115,6 @@ GlobalStringLiteralMap* SystemDomain::m_pGlobalStringLiteralMap = NULL;
 DECLSPEC_ALIGN(16) 
 static BYTE         g_pSystemDomainMemory[sizeof(SystemDomain)];
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-size_t              SystemDomain::m_totalSurvivedBytes = 0;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 CrstStatic          SystemDomain::m_SystemDomainCrst;
 CrstStatic          SystemDomain::m_DelayedUnloadCrst;
 
@@ -1949,12 +1945,6 @@ void SystemDomain::LazyInitGlobalStringLiteralMap()
         AppDomain* pAppDomain = ::GetAppDomain();
         if (pAppDomain && pAppDomain->IsActive())
         {
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-            if (g_fEnableARM)
-            {
-                sc->pCurrentDomain = pAppDomain;
-            }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
             pAppDomain->EnumStaticGCRefs(fn, sc);
         }
     }
@@ -1962,83 +1952,6 @@ void SystemDomain::LazyInitGlobalStringLiteralMap()
     RETURN;
 }
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-void SystemDomain::ResetADSurvivedBytes()
-{
-    CONTRACT_VOID
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACT_END;
-
-    _ASSERTE(GCHeapUtilities::IsGCInProgress());
-
-    SystemDomain* sysDomain = SystemDomain::System();
-    if (sysDomain)
-    {
-        AppDomain* pAppDomain = ::GetAppDomain();
-        if (pAppDomain && pAppDomain->IsUserActive())
-        {
-            pAppDomain->ResetSurvivedBytes();
-        }
-    }
-
-    RETURN;
-}
-
-ULONGLONG SystemDomain::GetADSurvivedBytes()
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACTL_END;
-
-    SystemDomain* sysDomain = SystemDomain::System();
-    ULONGLONG ullTotalADSurvived = 0;
-    if (sysDomain)
-    {
-        AppDomain* pAppDomain = ::GetAppDomain();
-        if (pAppDomain && pAppDomain->IsUserActive())
-        {
-            ULONGLONG ullSurvived = pAppDomain->GetSurvivedBytes();
-            ullTotalADSurvived += ullSurvived;
-        }
-    }
-
-    return ullTotalADSurvived;
-}
-
-void SystemDomain::RecordTotalSurvivedBytes(size_t totalSurvivedBytes)
-{
-    CONTRACT_VOID
-    {
-        NOTHROW;
-        GC_NOTRIGGER;
-        MODE_ANY;
-    }
-    CONTRACT_END;
-
-    m_totalSurvivedBytes = totalSurvivedBytes;
-
-    SystemDomain* sysDomain = SystemDomain::System();
-    if (sysDomain)
-    {
-        AppDomain* pAppDomain = ::GetAppDomain();
-        if (pAppDomain && pAppDomain->IsUserActive())
-        {
-            FireEtwAppDomainMemSurvived((ULONGLONG)pAppDomain, pAppDomain->GetSurvivedBytes(), totalSurvivedBytes, GetClrInstanceId());
-        }
-    }
-
-    RETURN;
-}
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 // Only called when EE is suspended.
 DWORD SystemDomain::GetTotalNumSizedRefHandles()
 {
@@ -2977,12 +2890,6 @@ AppDomain::AppDomain()
     m_dwCreationHolders=0;
 #endif
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    m_ullTotalProcessorUsage = 0;
-    m_pullAllocBytes = NULL;
-    m_pullSurvivedBytes = NULL;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifdef FEATURE_TYPEEQUIVALENCE
     m_pTypeEquivalenceTable = NULL;
 #endif // FEATURE_TYPEEQUIVALENCE
@@ -3080,27 +2987,6 @@ void AppDomain::Init()
 
 #ifndef CROSSGEN_COMPILE
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    // NOTE: it's important that we initialize ARM data structures before calling
-    // IGCHandleManager::CreateHandleStore, this is because AD::Init() can race with GC
-    // and once we add ourselves to the handle table map the GC can start walking
-    // our handles and calling AD::RecordSurvivedBytes() which touches ARM data.
-    if (GCHeapUtilities::IsServerHeap())
-        m_dwNumHeaps = CPUGroupInfo::CanEnableGCCPUGroups() ?
-                           CPUGroupInfo::GetNumActiveProcessors() :
-                           GetCurrentProcessCpuCount();
-    else
-        m_dwNumHeaps = 1;
-    m_pullAllocBytes = new ULONGLONG [m_dwNumHeaps * ARM_CACHE_LINE_SIZE_ULL];
-    m_pullSurvivedBytes = new ULONGLONG [m_dwNumHeaps * ARM_CACHE_LINE_SIZE_ULL];
-    for (DWORD i = 0; i < m_dwNumHeaps; i++)
-    {
-        m_pullAllocBytes[i * ARM_CACHE_LINE_SIZE_ULL] = 0;
-        m_pullSurvivedBytes[i * ARM_CACHE_LINE_SIZE_ULL] = 0;
-    }
-    m_ullLastEtwAllocBytes = 0;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     // Default domain reuses the handletablemap that was created during EEStartup
     m_handleStore = GCHandleUtilities::GetGCHandleManager()->GetGlobalHandleStore();
 
@@ -7070,66 +6956,6 @@ PTR_LoaderAllocator SystemDomain::GetGlobalLoaderAllocator()
     return PTR_LoaderAllocator(PTR_HOST_MEMBER_TADDR(SystemDomain,System(),m_GlobalAllocator));
 }
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
-#ifndef CROSSGEN_COMPILE
-// Return the total processor time (user and kernel) used by threads executing in this AppDomain so far. The
-// result is in 100ns units.
-ULONGLONG AppDomain::QueryProcessorUsage()
-{
-    CONTRACTL
-    {
-        NOTHROW;
-        GC_TRIGGERS;
-        MODE_ANY;
-    }
-    CONTRACTL_END;
-
-#ifndef DACCESS_COMPILE
-    Thread *pThread = NULL;
-
-    // Need to update our accumulated processor time count with current values from each thread that is
-    // currently executing in this domain.
-
-    // Take the thread store lock while we enumerate threads.
-    ThreadStoreLockHolder tsl;
-    while ((pThread = ThreadStore::GetThreadList(pThread)) != NULL)
-    {
-        // Skip unstarted and dead threads and those that are currently executing in a different AppDomain.
-        if (pThread->IsUnstarted() || pThread->IsDead() || pThread->GetDomain(INDEBUG(TRUE)) != this)
-            continue;
-
-        // Add the amount of time spent by the thread in the AppDomain since the last time we asked (calling
-        // Thread::QueryThreadProcessorUsage() will reset the thread's counter).
-        UpdateProcessorUsage(pThread->QueryThreadProcessorUsage());
-    }
-#endif // !DACCESS_COMPILE
-
-    // Return the updated total.
-    return m_ullTotalProcessorUsage;
-}
-
-// Add to the current count of processor time used by threads within this AppDomain. This API is called by
-// threads transitioning between AppDomains.
-void AppDomain::UpdateProcessorUsage(ULONGLONG ullAdditionalUsage)
-{
-    LIMITED_METHOD_CONTRACT;
-
-    // Need to be careful to synchronize here, multiple threads could be racing to update this count.
-    ULONGLONG ullOldValue;
-    ULONGLONG ullNewValue;
-    do
-    {
-        ullOldValue = m_ullTotalProcessorUsage;
-        ullNewValue = ullOldValue + ullAdditionalUsage;
-    } while (InterlockedCompareExchange64((LONGLONG*)&m_ullTotalProcessorUsage,
-                                          (LONGLONG)ullNewValue,
-                                          (LONGLONG)ullOldValue) != (LONGLONG)ullOldValue);
-}
-#endif // CROSSGEN_COMPILE
-
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #if defined(FEATURE_TYPEEQUIVALENCE)
 
 #ifndef DACCESS_COMPILE
diff --git a/src/vm/appdomain.hpp b/src/vm/appdomain.hpp
index 5bc45d7943..b2f2269771 100644
--- a/src/vm/appdomain.hpp
+++ b/src/vm/appdomain.hpp
@@ -2512,103 +2512,6 @@ public:
     PTR_LoaderHeap GetLowFrequencyHeap();
     PTR_LoaderHeap GetHighFrequencyHeap();
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    #define ARM_ETW_ALLOC_THRESHOLD (4 * 1024 * 1024)
-    // cache line size in ULONGLONG - 128 bytes which are 16 ULONGLONG's
-    #define ARM_CACHE_LINE_SIZE_ULL 16
-
-    inline ULONGLONG GetAllocBytes()
-    {
-        LIMITED_METHOD_CONTRACT;
-        ULONGLONG ullTotalAllocBytes = 0;
-
-        // Ensure that m_pullAllocBytes is non-null to avoid an AV in a race between GC and AD unload.
-        // A race can occur when a new appdomain is created, but an OOM is thrown when allocating for m_pullAllocBytes, causing the AD unload.
-        if(NULL != m_pullAllocBytes)
-        {
-            for (DWORD i = 0; i < m_dwNumHeaps; i++)
-            {
-                ullTotalAllocBytes += m_pullAllocBytes[i * ARM_CACHE_LINE_SIZE_ULL];
-            }
-        }
-        return ullTotalAllocBytes;
-    }
-
-    void RecordAllocBytes(size_t allocatedBytes, DWORD dwHeapNumber)
-    {
-        LIMITED_METHOD_CONTRACT;
-        _ASSERTE(dwHeapNumber < m_dwNumHeaps);
-        
-        // Ensure that m_pullAllocBytes is non-null to avoid an AV in a race between GC and AD unload.
-        // A race can occur when a new appdomain is created, but an OOM is thrown when allocating for m_pullAllocBytes, causing the AD unload.
-        if(NULL != m_pullAllocBytes)
-        {
-            m_pullAllocBytes[dwHeapNumber * ARM_CACHE_LINE_SIZE_ULL] += allocatedBytes;
-        }
-
-        ULONGLONG ullTotalAllocBytes = GetAllocBytes();
-
-        if ((ullTotalAllocBytes - m_ullLastEtwAllocBytes) >= ARM_ETW_ALLOC_THRESHOLD)
-        {
-            m_ullLastEtwAllocBytes = ullTotalAllocBytes;
-            FireEtwAppDomainMemAllocated((ULONGLONG)this, ullTotalAllocBytes, GetClrInstanceId());
-        }
-    }
-
-    inline ULONGLONG GetSurvivedBytes()
-    {
-        LIMITED_METHOD_CONTRACT;
-        ULONGLONG ullTotalSurvivedBytes = 0;
-
-        // Ensure that m_pullSurvivedBytes is non-null to avoid an AV in a race between GC and AD unload.
-        // A race can occur when a new appdomain is created, but an OOM is thrown when allocating for m_pullSurvivedBytes, causing the AD unload.
-        if(NULL != m_pullSurvivedBytes)
-        {
-            for (DWORD i = 0; i < m_dwNumHeaps; i++)
-            {
-                ullTotalSurvivedBytes += m_pullSurvivedBytes[i * ARM_CACHE_LINE_SIZE_ULL];
-            }
-        }
-        return ullTotalSurvivedBytes;
-    }
-
-    void RecordSurvivedBytes(size_t promotedBytes, DWORD dwHeapNumber)
-    {
-        WRAPPER_NO_CONTRACT;
-        _ASSERTE(dwHeapNumber < m_dwNumHeaps);
-   
-        // Ensure that m_pullSurvivedBytes is non-null to avoid an AV in a race between GC and AD unload.
-        // A race can occur when a new appdomain is created, but an OOM is thrown when allocating for m_pullSurvivedBytes, causing the AD unload.
-        if(NULL != m_pullSurvivedBytes)
-        {
-            m_pullSurvivedBytes[dwHeapNumber * ARM_CACHE_LINE_SIZE_ULL] += promotedBytes;
-        }
-    }
-
-    inline void ResetSurvivedBytes()
-    {
-        LIMITED_METHOD_CONTRACT;
-        
-        // Ensure that m_pullSurvivedBytes is non-null to avoid an AV in a race between GC and AD unload.
-        // A race can occur when a new appdomain is created, but an OOM is thrown when allocating for m_pullSurvivedBytes, causing the AD unload.
-        if(NULL != m_pullSurvivedBytes)
-        {
-            for (DWORD i = 0; i < m_dwNumHeaps; i++)
-            {
-                m_pullSurvivedBytes[i * ARM_CACHE_LINE_SIZE_ULL] = 0;
-            }
-        }
-    }
-
-    // Return the total processor time (user and kernel) used by threads executing in this AppDomain so far.
-    // The result is in 100ns units.
-    ULONGLONG QueryProcessorUsage();
-
-    // Add to the current count of processor time used by threads within this AppDomain. This API is called by
-    // threads transitioning between AppDomains.
-    void UpdateProcessorUsage(ULONGLONG ullAdditionalUsage);
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 private:
     size_t EstimateSize();
     EEClassFactoryInfoHashTable* SetupClassFactHash();
@@ -2749,17 +2652,6 @@ private:
     // The thread-pool index of this app domain among existing app domains (starting from 1)
     TPIndex m_tpIndex;
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    ULONGLONG* m_pullAllocBytes;
-    ULONGLONG* m_pullSurvivedBytes;
-    DWORD m_dwNumHeaps;
-    ULONGLONG m_ullLastEtwAllocBytes;
-    // Total processor time (user and kernel) utilized by threads running in this AppDomain so far. May not
-    // account for threads currently executing in the AppDomain until a call to QueryProcessorUsage() is
-    // made.
-    Volatile<ULONGLONG> m_ullTotalProcessorUsage;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     Volatile<Stage> m_Stage;
 
     ArrayList        m_failedAssemblies;
@@ -3220,19 +3112,6 @@ public:
 
 #endif // DACCESS_COMPILE
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    // The *AD* methods are what we got from tracing through EE roots.
-    // RecordTotalSurvivedBytes is the total promoted from a GC.
-    static void ResetADSurvivedBytes();
-    static ULONGLONG GetADSurvivedBytes();
-    static void RecordTotalSurvivedBytes(size_t totalSurvivedBytes);
-    static ULONGLONG GetTotalSurvivedBytes()
-    {
-        LIMITED_METHOD_CONTRACT;
-        return m_totalSurvivedBytes;
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     //****************************************************************************************
     // Routines to deal with the base library (currently mscorlib.dll)
     LPCWSTR BaseLibrary()
@@ -3341,11 +3220,6 @@ private:
 
     LoaderAllocator * m_pDelayedUnloadListOfLoaderAllocators;
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    // This is what gets promoted for the whole GC heap.
-    static size_t m_totalSurvivedBytes;
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifndef DACCESS_COMPILE
     static CrstStatic m_DelayedUnloadCrst;
     static CrstStatic       m_SystemDomainCrst;
diff --git a/src/vm/eeconfig.cpp b/src/vm/eeconfig.cpp
index a4b8e1d196..87e7467f23 100644
--- a/src/vm/eeconfig.cpp
+++ b/src/vm/eeconfig.cpp
@@ -712,11 +712,6 @@ HRESULT EEConfig::sync()
     iGCLatencyMode = GetConfigDWORD_DontUse_(CLRConfig::INTERNAL_GCLatencyMode, iGCLatencyMode);
 #endif
 
-    if (CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_ARMEnabled))
-    {
-        g_fEnableARM = TRUE;
-    }
-
     bool gcConcurrentWasForced = false;
     // The CLRConfig value for UNSUPPORTED_gcConcurrent defaults to -1, and treats any
     // positive value as 'forcing' concurrent GC to be on. Because the standard logic
diff --git a/src/vm/eepolicy.cpp b/src/vm/eepolicy.cpp
index 2da1c70f70..66ec5c6be2 100644
--- a/src/vm/eepolicy.cpp
+++ b/src/vm/eepolicy.cpp
@@ -1249,7 +1249,6 @@ void EEPolicy::HandleCodeContractFailure(LPCWSTR pMessage, LPCWSTR pCondition, L
     // GetActionOnFailure will notify the host for us.
     EPolicyAction action = pPolicy->GetActionOnFailure(FAIL_CodeContract);
     Thread* pThread = GetThread();
-    AppDomain* pCurrentDomain = ::GetAppDomain();
 
     switch(action) {
     case eThrowException:
diff --git a/src/vm/eventtrace.cpp b/src/vm/eventtrace.cpp
index a4e7d6ffe4..25f5273a05 100644
--- a/src/vm/eventtrace.cpp
+++ b/src/vm/eventtrace.cpp
@@ -3844,9 +3844,6 @@ VOID ETW::EnumerationLog::StartRundown()
 
     EX_TRY
     {
-        BOOL bIsArmRundownEnabled = ETW_TRACING_CATEGORY_ENABLED(MICROSOFT_WINDOWS_DOTNETRUNTIME_RUNDOWN_PROVIDER_Context,
-                                                                 TRACE_LEVEL_INFORMATION,
-                                                                 CLR_RUNDOWNAPPDOMAINRESOURCEMANAGEMENT_KEYWORD);
         BOOL bIsPerfTrackRundownEnabled = ETW_TRACING_CATEGORY_ENABLED(MICROSOFT_WINDOWS_DOTNETRUNTIME_RUNDOWN_PROVIDER_Context,
                                                                  TRACE_LEVEL_INFORMATION,
                                                                  CLR_RUNDOWNPERFTRACK_KEYWORD);
@@ -3869,8 +3866,6 @@ VOID ETW::EnumerationLog::StartRundown()
                                         TRACE_LEVEL_INFORMATION, 
                                         CLR_RUNDOWNJITTEDMETHODILTONATIVEMAP_KEYWORD)
            ||
-           bIsArmRundownEnabled
-           ||
            bIsPerfTrackRundownEnabled
            ||
            bIsThreadingRundownEnabled)
@@ -3909,17 +3904,7 @@ VOID ETW::EnumerationLog::StartRundown()
 
             ETW::EnumerationLog::EnumerationHelper(NULL, NULL, enumerationOptions);
             
-            if (bIsArmRundownEnabled)
-            {
-                // When an ETW event consumer asks for ARM rundown, that not only enables
-                // the ETW events, but also causes some minor behavioral changes in the
-                // CLR, such as gathering CPU usage baselines for each thread right now,
-                // and also gathering resource usage information later on (keyed off of
-                // g_fEnableARM, which we'll set right now).
-                EnableARM();
-            }
-
-            if (bIsArmRundownEnabled || bIsThreadingRundownEnabled)
+            if (bIsThreadingRundownEnabled)
             {
                 SendThreadRundownEvent();
             }
diff --git a/src/vm/frames.cpp b/src/vm/frames.cpp
index 312efe9f3b..8d49702cef 100644
--- a/src/vm/frames.cpp
+++ b/src/vm/frames.cpp
@@ -1111,7 +1111,7 @@ void HijackFrame::GcScanRoots(promote_func *fn, ScanContext* sc)
         case RT_ByRef:
             LOG((LF_GC, INFO3, "Hijack Frame Carefully Promoting pointer" FMT_ADDR "to",
                 DBG_ADDR(OBJECTREF_TO_UNCHECKED_OBJECTREF(*objPtr))));
-            PromoteCarefully(fn, objPtr, sc, GC_CALL_INTERIOR | GC_CALL_CHECK_APP_DOMAIN);
+            PromoteCarefully(fn, objPtr, sc, GC_CALL_INTERIOR);
             LOG((LF_GC, INFO3, FMT_ADDR "\n", DBG_ADDR(OBJECTREF_TO_UNCHECKED_OBJECTREF(*objPtr))));
             break;
 
@@ -1340,7 +1340,7 @@ void TransitionFrame::PromoteCallerStackUsingGCRefMap(promote_func* fn, ScanCont
             fn(dac_cast<PTR_PTR_Object>(ppObj), sc, CHECK_APP_DOMAIN);
             break;
         case GCREFMAP_INTERIOR:
-            PromoteCarefully(fn, dac_cast<PTR_PTR_Object>(ppObj), sc, GC_CALL_INTERIOR | GC_CALL_CHECK_APP_DOMAIN);
+            PromoteCarefully(fn, dac_cast<PTR_PTR_Object>(ppObj), sc, GC_CALL_INTERIOR);
             break;
         case GCREFMAP_METHOD_PARAM:
             if (sc->promotion)
diff --git a/src/vm/gcenv.ee.common.cpp b/src/vm/gcenv.ee.common.cpp
index 6915ec8bda..1411853218 100644
--- a/src/vm/gcenv.ee.common.cpp
+++ b/src/vm/gcenv.ee.common.cpp
@@ -158,7 +158,7 @@ void GcEnumObject(LPVOID pData, OBJECTREF *pObj, uint32_t flags)
     //
     // Sanity check that the flags contain only these three values
     //
-    assert((flags & ~(GC_CALL_INTERIOR|GC_CALL_PINNED|GC_CALL_CHECK_APP_DOMAIN)) == 0);
+    assert((flags & ~(GC_CALL_INTERIOR|GC_CALL_PINNED)) == 0);
 
     // for interior pointers, we optimize the case in which
     //  it points into the current threads stack area
@@ -205,13 +205,6 @@ StackWalkAction GcStackCrawlCallBack(CrawlFrame* pCF, VOID* pData)
 
     GCCONTEXT   *gcctx = (GCCONTEXT*) pData;
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableARM)
-    {
-        gcctx->sc->pCurrentDomain = pCF->GetAppDomain();
-    }
-#endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     MethodDesc *pMD = pCF->GetFunction();
 
 #ifdef GC_PROFILING
diff --git a/src/vm/gcenv.ee.cpp b/src/vm/gcenv.ee.cpp
index 8e47caee94..ebbc7929a6 100644
--- a/src/vm/gcenv.ee.cpp
+++ b/src/vm/gcenv.ee.cpp
@@ -1013,15 +1013,6 @@ void GCToEEInterface::HandleFatalError(unsigned int exitCode)
     EEPOLICY_HANDLE_FATAL_ERROR(exitCode);
 }
 
-bool GCToEEInterface::ShouldFinalizeObjectForUnload(void* pDomain, Object* obj)
-{
-    // CoreCLR does not have appdomains, so this code path is dead. Other runtimes may
-    // choose to inspect the object being finalized here.
-    // [DESKTOP TODO] Desktop looks for "agile and finalizable" objects and may choose
-    // to move them to a new app domain instead of finalizing them here.
-    return true;
-}
-
 bool GCToEEInterface::EagerFinalized(Object* obj)
 {
     MethodTable* pMT = obj->GetGCSafeMethodTable();
@@ -1486,34 +1477,6 @@ IGCToCLREventSink* GCToEEInterface::EventSink()
     return &g_gcToClrEventSink;
 }
 
-uint32_t GCToEEInterface::GetDefaultDomainIndex()
-{
-    LIMITED_METHOD_CONTRACT;
-
-    return DefaultADID;
-}
-
-void *GCToEEInterface::GetAppDomainAtIndex(uint32_t appDomainIndex)
-{
-    LIMITED_METHOD_CONTRACT;
-
-    return ::GetAppDomain();
-}
-
-bool GCToEEInterface::AppDomainCanAccessHandleTable(uint32_t appDomainID)
-{
-    LIMITED_METHOD_CONTRACT;
-
-    return appDomainID == DefaultADID;
-}
-
-uint32_t GCToEEInterface::GetIndexOfAppDomainBeingUnloaded()
-{
-    LIMITED_METHOD_CONTRACT;
-
-    return 0xFFFFFFFF;
-}
-
 uint32_t GCToEEInterface::GetTotalNumSizedRefHandles()
 {
     LIMITED_METHOD_CONTRACT;
@@ -1522,13 +1485,6 @@ uint32_t GCToEEInterface::GetTotalNumSizedRefHandles()
 }
 
 
-bool GCToEEInterface::AppDomainIsRudeUnload(void *appDomain)
-{
-    LIMITED_METHOD_CONTRACT;
-
-    return false;
-}
-
 bool GCToEEInterface::AnalyzeSurvivorsRequested(int condemnedGeneration)
 {
     LIMITED_METHOD_CONTRACT;
diff --git a/src/vm/gcenv.ee.h b/src/vm/gcenv.ee.h
index 383c0796f6..de6ad5a542 100644
--- a/src/vm/gcenv.ee.h
+++ b/src/vm/gcenv.ee.h
@@ -62,7 +62,6 @@ public:
 
     void EnableFinalization(bool foundFinalizers);
     void HandleFatalError(unsigned int exitCode);
-    bool ShouldFinalizeObjectForUnload(void* pDomain, Object* obj);
     bool EagerFinalized(Object* obj);
     MethodTable* GetFreeObjectMethodTable();
     bool GetBooleanConfigValue(const char* key, bool* value);
@@ -76,12 +75,7 @@ public:
     void WalkAsyncPinned(Object* object, void* context, void(*callback)(Object*, Object*, void*));
     IGCToCLREventSink* EventSink();
 
-    uint32_t GetDefaultDomainIndex();
-    void *GetAppDomainAtIndex(uint32_t appDomainIndex);
-    bool AppDomainCanAccessHandleTable(uint32_t appDomainID);
-    uint32_t GetIndexOfAppDomainBeingUnloaded();
     uint32_t GetTotalNumSizedRefHandles();
-    bool AppDomainIsRudeUnload(void *appDomain);
 
     bool AnalyzeSurvivorsRequested(int condemnedGeneration);
     void AnalyzeSurvivorsFinished(int condemnedGeneration);
diff --git a/src/vm/gcenv.h b/src/vm/gcenv.h
index 162c14557e..767adb892c 100644
--- a/src/vm/gcenv.h
+++ b/src/vm/gcenv.h
@@ -68,22 +68,4 @@ namespace ETW
 #define _tfopen _wfopen
 #endif
 
-// -----------------------------------------------------------------------------------------------------------
-//
-// AppDomain emulation. We don't have these in the CLR anymore so instead we emulate the bare minimum of the API
-// touched by the GC/HandleTable and pretend we have precisely one (default) appdomain.
-//
-
-#define RH_DEFAULT_DOMAIN_ID 1
-
-struct ADIndex
-{
-    DWORD m_dwIndex;
-
-    ADIndex () : m_dwIndex(RH_DEFAULT_DOMAIN_ID) {}
-    explicit ADIndex (DWORD id) : m_dwIndex(id) {}
-    BOOL operator==(const ADIndex& ad) const { return m_dwIndex == ad.m_dwIndex; }
-    BOOL operator!=(const ADIndex& ad) const { return m_dwIndex != ad.m_dwIndex; }
-};
-
 #endif // GCENV_H_
diff --git a/src/vm/gctoclreventsink.cpp b/src/vm/gctoclreventsink.cpp
index d95a187c1d..4d64a49555 100644
--- a/src/vm/gctoclreventsink.cpp
+++ b/src/vm/gctoclreventsink.cpp
@@ -319,14 +319,14 @@ void GCToCLREventSink::FireGCFullNotify_V1(uint32_t genNumber, uint32_t isAlloc)
     FireEtwGCFullNotify_V1(genNumber, isAlloc, GetClrInstanceId());
 }
 
-void GCToCLREventSink::FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID)
+void GCToCLREventSink::FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation)
 {
-    FireEtwSetGCHandle(handleID, objectID, kind, generation, appDomainID, GetClrInstanceId());
+    FireEtwSetGCHandle(handleID, objectID, kind, generation, (uint64_t)dac_cast<TADDR>(AppDomain::GetCurrentDomain()), GetClrInstanceId());
 }
 
-void GCToCLREventSink::FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID)
+void GCToCLREventSink::FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation)
 {
-    FireEtwPrvSetGCHandle(handleID, objectID, kind, generation, appDomainID, GetClrInstanceId());
+    FireEtwPrvSetGCHandle(handleID, objectID, kind, generation, (uint64_t)dac_cast<TADDR>(AppDomain::GetCurrentDomain()), GetClrInstanceId());
 }
 
 void GCToCLREventSink::FireDestroyGCHandle(void *handleID)
diff --git a/src/vm/gctoclreventsink.h b/src/vm/gctoclreventsink.h
index 1e2edfccc2..12f5ae3cc5 100644
--- a/src/vm/gctoclreventsink.h
+++ b/src/vm/gctoclreventsink.h
@@ -76,8 +76,8 @@ public:
     void FireBGCAllocWaitBegin(uint32_t reason);
     void FireBGCAllocWaitEnd(uint32_t reason);
     void FireGCFullNotify_V1(uint32_t genNumber, uint32_t isAlloc);
-    void FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID);
-    void FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation, uint64_t appDomainID);
+    void FireSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation);
+    void FirePrvSetGCHandle(void *handleID, void *objectID, uint32_t kind, uint32_t generation);
     void FireDestroyGCHandle(void *handleID);
     void FirePrvDestroyGCHandle(void *handleID);
 };
diff --git a/src/vm/siginfo.cpp b/src/vm/siginfo.cpp
index 353abf48cb..0397b5aa8b 100644
--- a/src/vm/siginfo.cpp
+++ b/src/vm/siginfo.cpp
@@ -4871,7 +4871,7 @@ void PromoteCarefully(promote_func   fn,
     //
     // Sanity check that the flags contain only these three values
     //
-    assert((flags & ~(GC_CALL_INTERIOR|GC_CALL_PINNED|GC_CALL_CHECK_APP_DOMAIN)) == 0);
+    assert((flags & ~(GC_CALL_INTERIOR|GC_CALL_PINNED)) == 0);
 
     //
     // Sanity check that GC_CALL_INTERIOR FLAG is set
@@ -5010,7 +5010,7 @@ VOID MetaSig::GcScanRoots(ArgDestination *pValue,
 #ifdef _DEBUG
             pOldLocation = *pArgPtr;
 #endif
-            (*fn)(pArgPtr, sc, GC_CALL_CHECK_APP_DOMAIN );
+            (*fn)(pArgPtr, sc, 0 );
 
             // !!! Do not cast to (OBJECTREF*)
             // !!! If we are in the relocate phase, we may have updated root,
@@ -5038,7 +5038,7 @@ VOID MetaSig::GcScanRoots(ArgDestination *pValue,
             pOldLocation = *pArgPtr;
 #endif
 
-            (*fnc)(fn, pArgPtr, sc, GC_CALL_INTERIOR|GC_CALL_CHECK_APP_DOMAIN);
+            (*fnc)(fn, pArgPtr, sc, GC_CALL_INTERIOR);
 
             // !!! Do not cast to (OBJECTREF*)
             // !!! If we are in the relocate phase, we may have updated root,
diff --git a/src/vm/threads.cpp b/src/vm/threads.cpp
index 020f318684..07ea78f8a0 100644
--- a/src/vm/threads.cpp
+++ b/src/vm/threads.cpp
@@ -808,13 +808,6 @@ Thread* SetupThread(BOOL fInternal)
         FastInterlockOr((ULONG *) &pThread->m_State, Thread::TS_TPWorkerThread);
     }
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableARM)
-    {
-        pThread->QueryThreadProcessorUsage();
-    }
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifdef FEATURE_EVENT_TRACE
     ETW::ThreadLog::FireThreadCreated(pThread);
 #endif // FEATURE_EVENT_TRACE
@@ -865,15 +858,6 @@ void DestroyThread(Thread *th)
 
     _ASSERTE(g_fEEShutDown || th->m_dwLockCount == 0 || th->m_fRudeAborted);
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableARM)
-    {
-        AppDomain* pDomain = th->GetDomain();
-        pDomain->UpdateProcessorUsage(th->QueryThreadProcessorUsage());
-        FireEtwThreadTerminated((ULONGLONG)th, (ULONGLONG)pDomain, GetClrInstanceId());
-    }
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     th->FinishSOWork();
 
     GCX_PREEMP_NO_DTOR();
@@ -966,14 +950,6 @@ HRESULT Thread::DetachThread(BOOL fDLLThreadDetach)
 
     _ASSERTE (this == GetThread());
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    if (g_fEnableARM && m_pDomain)
-    {
-        m_pDomain->UpdateProcessorUsage(QueryThreadProcessorUsage());
-        FireEtwThreadTerminated((ULONGLONG)this, (ULONGLONG)m_pDomain, GetClrInstanceId());
-    }
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
     FinishSOWork();
 
     FastInterlockIncrement(&Thread::m_DetachCount);
@@ -1555,10 +1531,6 @@ Thread::Thread()
     contextHolder.SuppressRelease();
     savedRedirectContextHolder.SuppressRelease();
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    m_ullProcessorUsageBaseline = 0;
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 #ifdef FEATURE_COMINTEROP
     m_uliInitializeSpyCookie.QuadPart = 0ul;
     m_fInitializeSpyRegistered = false;
@@ -1825,12 +1797,6 @@ BOOL Thread::HasStarted(BOOL bRequiresTSL)
 
         ThreadStore::TransferStartedThread(this, bRequiresTSL);
 
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-        if (g_fEnableARM)
-        {
-            QueryThreadProcessorUsage();
-        }
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
 #ifdef FEATURE_EVENT_TRACE
         ETW::ThreadLog::FireThreadCreated(this);
 #endif // FEATURE_EVENT_TRACE
@@ -8918,56 +8884,6 @@ ThreadStore::EnumMemoryRegions(CLRDataEnumMemoryFlags flags)
 
 #endif // #ifdef DACCESS_COMPILE
 
-
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-// For the purposes of tracking resource usage we implement a simple cpu resource usage counter on each
-// thread. Every time QueryThreadProcessorUsage() is invoked it returns the amount of cpu time (a combination
-// of user and kernel mode time) used since the last call to QueryThreadProcessorUsage(). The result is in 100
-// nanosecond units.
-ULONGLONG Thread::QueryThreadProcessorUsage()
-{
-    LIMITED_METHOD_CONTRACT;
-
-    // Get current values for the amount of kernel and user time used by this thread over its entire lifetime.
-    FILETIME sCreationTime, sExitTime, sKernelTime, sUserTime;
-    HANDLE hThread = GetThreadHandle();
-    BOOL fResult = GetThreadTimes(hThread,
-                                  &sCreationTime,
-                                  &sExitTime,
-                                  &sKernelTime,
-                                  &sUserTime);
-    if (!fResult)
-    {
-#ifdef _DEBUG
-        ULONG error = GetLastError();
-        printf("GetThreadTimes failed: %d; handle is %p\n", error, hThread);
-        _ASSERTE(FALSE);
-#endif
-        return 0;
-    }
-
-    // Combine the user and kernel times into a single value (FILETIME is just a structure representing an
-    // unsigned int64 in two 32-bit pieces).
-    _ASSERTE(sizeof(FILETIME) == sizeof(UINT64));
-    ULONGLONG ullCurrentUsage = *(ULONGLONG*)&sKernelTime + *(ULONGLONG*)&sUserTime;
-
-    // Store the current processor usage as the new baseline, and retrieve the previous usage.
-    ULONGLONG ullPreviousUsage = VolatileLoad(&m_ullProcessorUsageBaseline);
-    if (ullPreviousUsage >= ullCurrentUsage ||
-        ullPreviousUsage != (ULONGLONG)InterlockedCompareExchange64(
-            (LONGLONG*)&m_ullProcessorUsageBaseline, 
-            (LONGLONG)ullCurrentUsage, 
-            (LONGLONG)ullPreviousUsage))
-    {
-        // another thread beat us to it, and already reported this usage.  
-        return 0; 
-    }
-
-    // The result is the difference between this value and the previous usage value.
-    return ullCurrentUsage - ullPreviousUsage;
-}
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
 OBJECTHANDLE Thread::GetOrCreateDeserializationTracker()
 {
     CONTRACTL
diff --git a/src/vm/threads.h b/src/vm/threads.h
index 68a66c3284..6b7fe45368 100644
--- a/src/vm/threads.h
+++ b/src/vm/threads.h
@@ -4835,18 +4835,8 @@ public:
     // Holds per-thread information the debugger uses to expose locking information
     // See ThreadDebugBlockingInfo.h for more details
     ThreadDebugBlockingInfo DebugBlockingInfo;
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    // For the purposes of tracking resource usage we implement a simple cpu resource usage counter on each
-    // thread. Every time QueryThreadProcessorUsage() is invoked it returns the amount of cpu time (a
-    // combination of user and kernel mode time) used since the last call to QueryThreadProcessorUsage(). The
-    // result is in 100 nanosecond units.
-    ULONGLONG QueryThreadProcessorUsage();
 
 private:
-    // The amount of processor time (both user and kernel) in 100ns units used by this thread at the time of
-    // the last call to QueryThreadProcessorUsage().
-    ULONGLONG m_ullProcessorUsageBaseline;
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
 
     // Disables pumping and thread join in RCW creation
     bool m_fDisableComObjectEagerCleanup;
@@ -4854,7 +4844,6 @@ private:
     // See ThreadStore::TriggerGCForDeadThreadsIfNecessary()
     bool m_fHasDeadThreadBeenConsideredForGCTrigger;
 
-private:
     CLRRandom m_random;
 
 public:
diff --git a/src/vm/util.cpp b/src/vm/util.cpp
index fafbf5bbb2..0a21d3da6d 100644
--- a/src/vm/util.cpp
+++ b/src/vm/util.cpp
@@ -3148,49 +3148,6 @@ BOOL DelayLoadOleaut32CheckDisabled()
 }
 #endif
 
-BOOL EnableARM()
-{
-#ifdef FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    CONTRACTL
-    {
-        NOTHROW;
-        // TODO: this should really be GC_TRIGGERS so we wouldn't need the 
-        // CONTRACT_VIOLATION below but the hosting API that calls this
-        // can be called on a COOP thread and it has a GC_NOTRIGGER contract. 
-        // We should use the AD unload thread to call this function on.
-        GC_NOTRIGGER;
-    }
-    CONTRACTL_END;
-
-    BOOL fARMEnabled = g_fEnableARM;
-
-    if (!fARMEnabled)
-    {
-        if (ThreadStore::s_pThreadStore)
-        {
-            // We need to establish the baselines for the CPU usage counting.
-            Thread *pThread = NULL;
-            CONTRACT_VIOLATION(GCViolation);
-
-            // Take the thread store lock while we enumerate threads.
-            ThreadStoreLockHolder tsl ;
-
-            while ((pThread = ThreadStore::GetThreadList(pThread)) != NULL)
-            {
-                if (pThread->IsUnstarted() || pThread->IsDead())
-                    continue;
-                pThread->QueryThreadProcessorUsage();
-            }
-        }
-        g_fEnableARM = TRUE;
-    }
-
-    return fARMEnabled;
-#else // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-    return FALSE;
-#endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-}
-
 #endif // !DACCESS_COMPILE && !CROSSGEN_COMPILE
 
 
diff --git a/src/vm/util.hpp b/src/vm/util.hpp
index 512f09f87b..d1086a9337 100644
--- a/src/vm/util.hpp
+++ b/src/vm/util.hpp
@@ -1114,11 +1114,6 @@ extern LONG g_OLEAUT32_Loaded;
 
 BOOL DbgIsExecutable(LPVOID lpMem, SIZE_T length);
 
-#ifndef DACCESS_COMPILE
-// returns if ARM was already enabled or not.
-BOOL EnableARM();
-#endif // !DACCESS_COMPILE
-
 int GetRandomInt(int maxVal);
 
 //
diff --git a/src/vm/vars.cpp b/src/vm/vars.cpp
index 8b329d4c2e..0887f2e0f1 100644
--- a/src/vm/vars.cpp
+++ b/src/vm/vars.cpp
@@ -185,8 +185,6 @@ int g_IGCTrimCommit = 0;
 
 BOOL g_fEnableETW = FALSE;
 
-BOOL g_fEnableARM = FALSE;
-
 //
 // Global state variable indicating if the EE is in its init phase.
 //
diff --git a/src/vm/vars.hpp b/src/vm/vars.hpp
index e4b790836e..25d46c2cc0 100644
--- a/src/vm/vars.hpp
+++ b/src/vm/vars.hpp
@@ -482,7 +482,6 @@ extern int g_IGCTrimCommit;
 #endif
 
 extern BOOL g_fEnableETW;
-extern BOOL g_fEnableARM;
 
 // Returns a BOOL to indicate if the runtime is active or not
 BOOL IsRuntimeActive();