[Local GC] Refactor usage of GC-internal functions in the DAC (#12458)

* Refactor usage of GC-internal functions in the DAC

* Fix one debugger test failure, one to go

17 files changed, 164 insertions, 49 deletions

diff --git a/src/debug/daccess/daccess.cpp b/src/debug/daccess/daccess.cpp
index 14ce251bfc..9d371ceff7 100644
--- a/src/debug/daccess/daccess.cpp
+++ b/src/debug/daccess/daccess.cpp
@@ -29,6 +29,7 @@
 #endif
 
 #include "dwbucketmanager.hpp"
+#include "gcinterface.dac.h"
 
 // To include definiton of IsThrowableThreadAbortException
 // #include <exstatecommon.h>
@@ -7932,8 +7933,6 @@ STDAPI OutOfProcessExceptionEventDebuggerLaunchCallback(__in PDWORD pContext,
 
 // DacHandleEnum
 
-// TODO(Local GC) - The DAC should not include GC headers
-#include "../../gc/handletablepriv.h"
 #include "comcallablewrapper.h"
 
 DacHandleWalker::DacHandleWalker()
@@ -7987,7 +7986,7 @@ HRESULT DacHandleWalker::Init(UINT32 typemask)
 {
     SUPPORTS_DAC;
     
-    mMap = &g_HandleTableMap;
+    mMap = g_gcDacGlobals->handle_table_map;
     mTypeMask = typemask;
     
     return S_OK;
@@ -8065,7 +8064,7 @@ bool DacHandleWalker::FetchMoreHandles(HANDLESCANPROC callback)
         {
             for (int i = 0; i < max_slots; ++i)
             {
-                HHANDLETABLE hTable = mMap->pBuckets[mIndex]->pTable[i];
+                DPTR(dac_handle_table) hTable = mMap->pBuckets[mIndex]->pTable[i];
                 if (hTable)
                 {
                     // Yikes!  The handle table callbacks don't produce the handle type or 
@@ -8079,8 +8078,8 @@ bool DacHandleWalker::FetchMoreHandles(HANDLESCANPROC callback)
                     {
                         if (mask & 1)
                         {
-                            HandleTable *pTable = (HandleTable *)hTable;
-                            PTR_AppDomain pDomain = SystemDomain::GetAppDomainAtIndex(pTable->uADIndex);
+                            dac_handle_table *pTable = hTable;
+                            PTR_AppDomain pDomain = SystemDomain::GetAppDomainAtIndex(ADIndex(pTable->uADIndex));
                             param.AppDomain = TO_CDADDR(pDomain.GetAddr());
                             param.Type = handleType;
                             
diff --git a/src/debug/daccess/dacdbiimpl.cpp b/src/debug/daccess/dacdbiimpl.cpp
index f48ecc0bd0..f274e703a2 100644
--- a/src/debug/daccess/dacdbiimpl.cpp
+++ b/src/debug/daccess/dacdbiimpl.cpp
@@ -5716,7 +5716,7 @@ BOOL DacDbiInterfaceImpl::IsVmObjectHandleValid(VMPTR_OBJECTHANDLE vmHandle)
     // SEH exceptions will be caught
     EX_TRY
     {
-        OBJECTREF objRef = HndFetchHandle((OBJECTHANDLE)vmHandle.GetDacPtr());
+        OBJECTREF objRef = ObjectFromHandle((OBJECTHANDLE)vmHandle.GetDacPtr());
 
         // NULL is certainly valid...
         if (objRef != NULL)
diff --git a/src/debug/daccess/dacimpl.h b/src/debug/daccess/dacimpl.h
index c3a1c46f68..c37face4e6 100644
--- a/src/debug/daccess/dacimpl.h
+++ b/src/debug/daccess/dacimpl.h
@@ -14,10 +14,7 @@
 #ifndef __DACIMPL_H__
 #define __DACIMPL_H__
 
-// This header include will need to be removed as part of GitHub#12170.
-// The only reason it's here now is that this header references the GC-private
-// structure "HandleTableMap".
-#include "../../gc/objecthandle.h"
+#include "gcinterface.dac.h"
 
 #if defined(_TARGET_ARM_) || defined(FEATURE_CORESYSTEM) // @ARMTODO: STL breaks the build with current VC headers
 //---------------------------------------------------------------------------------------
@@ -2242,7 +2239,7 @@ private:
     ULONG32 m_instanceAge;
     
     // Handle table walking variables.
-    HandleTableMap *mMap;
+    dac_handle_table_map *mMap;
     int mIndex;
     UINT32 mTypeMask;
     int mGenerationFilter;
diff --git a/src/debug/daccess/gcinterface.dac.h b/src/debug/daccess/gcinterface.dac.h
index 031ec36f30..c7765ef364 100644
--- a/src/debug/daccess/gcinterface.dac.h
+++ b/src/debug/daccess/gcinterface.dac.h
@@ -1,5 +1,54 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
+#ifndef __DACCESS_GCINTERFACE_DAC_H__
+#define __DACCESS_GCINTERFACE_DAC_H__
 
 #include "../../gc/gcinterface.dac.h"
+
+// The following six function prototypes are for functions that are used by the DAC
+// to inspect the handle table in detail. The semantics of these functions MUST be
+// versioned along with the rest of this interface - any changes in semantics
+// must be accompanied with a major versino bump.
+// 
+// Please do not add any additional functions to this list; we'd like to keep it
+// to an absolute minimum.
+#ifdef DACCESS_COMPILE
+// for DAC builds, OBJECTHANDLE is a uintptr_t.
+GC_DAC_VISIBLE
+OBJECTREF GetDependentHandleSecondary(OBJECTHANDLE handle);
+
+GC_DAC_VISIBLE_NO_MANGLE
+void HndScanHandlesForGC(
+    DPTR(dac_handle_table) hTable,
+    HANDLESCANPROC scanProc,
+    uintptr_t param1,
+    uintptr_t param2,
+    const uint32_t *types,
+    uint32_t typeCount,
+    uint32_t condemned,
+    uint32_t maxGen,
+    uint32_t flags);
+
+GC_DAC_VISIBLE_NO_MANGLE
+void HndEnumHandles(
+    DPTR(dac_handle_table) hTable,
+    const uint32_t *puType,
+    uint32_t uTypeCount,
+    HANDLESCANPROC pfnEnum,
+    uintptr_t lParam1,
+    uintptr_t lParam2,
+    bool fAsync);
+
+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
+
+#endif // __DACCESS_GCINTERFACE_DAC_H__
diff --git a/src/debug/daccess/request.cpp b/src/debug/daccess/request.cpp
index ebaa1f833f..806c288bbb 100644
--- a/src/debug/daccess/request.cpp
+++ b/src/debug/daccess/request.cpp
@@ -13,8 +13,6 @@
 #include "stdafx.h"
 #include <win32threadpool.h>
 
-// TODO(Local GC) - The DAC should not include GC headers
-#include <../../gc/handletablepriv.h>
 #include "typestring.h"
 #include <gccover.h>
 #include <virtualcallstub.h>
@@ -3871,7 +3869,7 @@ HRESULT ClrDataAccess::GetClrWatsonBucketsWorker(Thread * pThread, GenericModeBl
     if (ohThrowable != NULL)
     {
         // Get the object from handle and check if the throwable is preallocated or not
-        OBJECTREF oThrowable = ::HndFetchHandle(ohThrowable);
+        OBJECTREF oThrowable = ObjectFromHandle(ohThrowable);
         if (oThrowable != NULL)
         {
             // Does the throwable have buckets?
@@ -4165,7 +4163,7 @@ HRESULT ClrDataAccess::GetCCWData(CLRDATA_ADDRESS ccw, struct DacpCCWData *ccwDa
     ccwData->isAggregated = pCCW->GetSimpleWrapper()->IsAggregated();
 
     if (pCCW->GetObjectHandle() != NULL)
-        ccwData->managedObject = PTR_CDADDR(::HndFetchHandle(pCCW->GetObjectHandle()));
+        ccwData->managedObject = PTR_CDADDR(ObjectFromHandle(pCCW->GetObjectHandle()));
 
     // count the number of COM vtables
     ccwData->interfaceCount = 0;
diff --git a/src/gc/gc.h b/src/gc/gc.h
index 52252b8be3..4e722c4304 100644
--- a/src/gc/gc.h
+++ b/src/gc/gc.h
@@ -249,11 +249,13 @@ void TouchPages(void * pStart, size_t cb);
 void updateGCShadow(Object** ptr, Object* val);
 #endif
 
+#ifndef DACCESS_COMPILE
 // The single GC heap instance, shared with the VM.
 extern IGCHeapInternal* g_theGCHeap;
 
 // The single GC handle manager instance, shared with the VM.
 extern IGCHandleManager* g_theGCHandleManager;
+#endif // DACCESS_COMPILE
 
 #ifndef DACCESS_COMPILE
 inline bool IsGCInProgress(bool bConsiderGCStart = false)
diff --git a/src/gc/gccommon.cpp b/src/gc/gccommon.cpp
index 3e45eb60d5..92c0e7b7b5 100644
--- a/src/gc/gccommon.cpp
+++ b/src/gc/gccommon.cpp
@@ -124,6 +124,8 @@ namespace SVR
     extern void PopulateDacVars(GcDacVars* dacVars);
 }
 
+extern void PopulateHandleTableDacVars(GcDacVars* dacVars);
+
 //------------------------------------------------------------------
 // Externally-facing GC symbols, used to initialize the GC
 // -----------------------------------------------------------------
@@ -203,6 +205,7 @@ InitializeGarbageCollector(
     WKS::PopulateDacVars(gcDacVars);
 #endif
 
+    PopulateHandleTableDacVars(gcDacVars);
     if (heap == nullptr)
     {
         return false;
diff --git a/src/gc/gcinterface.dac.h b/src/gc/gcinterface.dac.h
index 647101fa1f..93698c05a9 100644
--- a/src/gc/gcinterface.dac.h
+++ b/src/gc/gcinterface.dac.h
@@ -11,12 +11,14 @@
 //      GC-internal type's fields, while still maintaining the same layout.
 // This interface is strictly versioned, see gcinterface.dacvars.def for more information.
 
-#define NUM_GC_DATA_POINTS             9
-#define MAX_COMPACT_REASONS_COUNT      11
-#define MAX_EXPAND_MECHANISMS_COUNT    6
-#define MAX_GC_MECHANISM_BITS_COUNT    2
-#define MAX_GLOBAL_GC_MECHANISMS_COUNT 6
-#define NUMBERGENERATIONS              4
+#define NUM_GC_DATA_POINTS              9
+#define MAX_COMPACT_REASONS_COUNT       11
+#define MAX_EXPAND_MECHANISMS_COUNT     6
+#define MAX_GC_MECHANISM_BITS_COUNT     2
+#define MAX_GLOBAL_GC_MECHANISMS_COUNT  6
+#define NUMBERGENERATIONS               4
+#define INITIAL_HANDLE_TABLE_ARRAY_SIZE 10
+#define HANDLE_MAX_INTERNAL_TYPES       12
 
 // Analogue for the GC heap_segment class, containing information regarding a single
 // heap segment.
@@ -49,6 +51,32 @@ public:
     uint8_t** m_FillPointers[NUMBERGENERATIONS + ExtraSegCount];
 };
 
+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 {
+public:
+    DPTR(DPTR(dac_handle_table)) pTable;
+    uint32_t HandleTableIndex;
+};
+
+class dac_handle_table_map {
+public:
+    DPTR(DPTR(dac_handle_table_bucket)) pBuckets;
+    DPTR(dac_handle_table_map) pNext;
+    uint32_t dwMaxIndex;
+};
+
 // Possible values of the current_c_gc_state dacvar, indicating the state of
 // a background GC.
 enum c_gc_state
@@ -132,6 +160,23 @@ public:
 };
 
 
+// The DAC links against six symbols that build as part of the VM DACCESS_COMPILE
+// build. These symbols are considered to be GC-private functions, but the DAC needs
+// to use them in order to perform some handle-related functions. These six functions
+// are adorned by this macro to make clear that their implementations must be versioned
+// alongside the rest of this file.
+//
+// Practically, this macro ensures that the target symbols aren't mangled, since the
+// DAC calls them with a signature slightly different than the one used when they
+// were defined.
+#define GC_DAC_VISIBLE
+
+#ifdef DACCESS_COMPILE
+#define GC_DAC_VISIBLE_NO_MANGLE extern "C"
+#else
+#define GC_DAC_VISIBLE_NO_MANGLE
+#endif // DACCESS_COMPILE
+
 // The actual structure containing the DAC variables. When DACCESS_COMPILE is not
 // defined (i.e. the normal runtime build), this structure contains pointers to the
 // GC's global DAC variabels. When DACCESS_COMPILE is defined (i.e. the DAC build),
@@ -142,9 +187,7 @@ struct GcDacVars {
   uint8_t minor_version_number;
   size_t generation_size;
 #ifdef DACCESS_COMPILE
- #define GC_DAC_VAR(type, name) DPTR(type) name;
- // ArrayDPTR doesn't allow decaying arrays to pointers, which
- // avoids some accidental errors.
+ #define GC_DAC_VAR(type, name)       DPTR(type) name;
  #define GC_DAC_PTR_VAR(type, name)   DPTR(type*) name;
  #define GC_DAC_ARRAY_VAR(type, name) DPTR(type) name;
 #else
diff --git a/src/gc/gcinterface.dacvars.def b/src/gc/gcinterface.dacvars.def
index b788079dcb..89cb01206f 100644
--- a/src/gc/gcinterface.dacvars.def
+++ b/src/gc/gcinterface.dacvars.def
@@ -60,6 +60,7 @@ GC_DAC_ARRAY_VAR  (size_t,                interesting_data_per_heap)
 GC_DAC_ARRAY_VAR  (size_t,                compact_reasons_per_heap)
 GC_DAC_ARRAY_VAR  (size_t,                expand_mechanisms_per_heap)
 GC_DAC_ARRAY_VAR  (size_t,                interesting_mechanism_bits_per_heap)
+GC_DAC_VAR        (dac_handle_table_map,  handle_table_map)
 
 #undef GC_DAC_VAR
 #undef GC_DAC_ARRAY_VAR
diff --git a/src/gc/handletable.cpp b/src/gc/handletable.cpp
index 8c6c835200..4942f017ac 100644
--- a/src/gc/handletable.cpp
+++ b/src/gc/handletable.cpp
@@ -263,6 +263,7 @@ ADIndex HndGetHandleTableADIndex(HHANDLETABLE hTable)
  *
  * Retrieves the AppDomain index associated with a handle table at creation
  */
+GC_DAC_VISIBLE
 ADIndex HndGetHandleADIndex(OBJECTHANDLE handle)
 {
     WRAPPER_NO_CONTRACT;
@@ -570,6 +571,7 @@ uintptr_t HndCompareExchangeHandleExtraInfo(OBJECTHANDLE handle, uint32_t uType,
  * Retrieves owner data from handle.
  *
  */
+GC_DAC_VISIBLE
 uintptr_t HndGetHandleExtraInfo(OBJECTHANDLE handle)
 {
     WRAPPER_NO_CONTRACT;
@@ -659,6 +661,7 @@ void HndLogSetEvent(OBJECTHANDLE handle, _UNCHECKED_OBJECTREF value)
 #endif
 }
 
+#ifndef DACCESS_COMPILE
 /*
  * HndWriteBarrier
  *
@@ -733,6 +736,7 @@ void HndWriteBarrier(OBJECTHANDLE handle, OBJECTREF objref)
         }
     }
 }
+#endif // DACCESS_COMPILE
 
 /*
  * HndEnumHandles
@@ -743,6 +747,7 @@ void HndWriteBarrier(OBJECTHANDLE handle, OBJECTREF objref)
  * needs to enumerate all roots in the handle table.
  *
  */
+GC_DAC_VISIBLE_NO_MANGLE
 void HndEnumHandles(HHANDLETABLE hTable, const uint32_t *puType, uint32_t uTypeCount,
                     HANDLESCANPROC pfnEnum, uintptr_t lParam1, uintptr_t lParam2, bool fAsync)
 {
@@ -803,6 +808,7 @@ void HndEnumHandles(HHANDLETABLE hTable, const uint32_t *puType, uint32_t uTypeC
  * as it scans.
  *
  */
+GC_DAC_VISIBLE_NO_MANGLE
 void HndScanHandlesForGC(HHANDLETABLE hTable, HANDLESCANPROC scanProc, uintptr_t param1, uintptr_t param2,
                          const uint32_t *types, uint32_t typeCount, uint32_t condemned, uint32_t maxgen, uint32_t flags)
 {
diff --git a/src/gc/handletable.h b/src/gc/handletable.h
index a952ad799f..70959edf3b 100644
--- a/src/gc/handletable.h
+++ b/src/gc/handletable.h
@@ -63,6 +63,8 @@ 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
@@ -81,6 +83,7 @@ void            HndSetHandleExtraInfo(OBJECTHANDLE handle, uint32_t uType, uintp
 uintptr_t          HndCompareExchangeHandleExtraInfo(OBJECTHANDLE handle, uint32_t uType, uintptr_t lOldExtraInfo, uintptr_t lNewExtraInfo);
 #endif // !DACCESS_COMPILE
 
+GC_DAC_VISIBLE
 uintptr_t          HndGetHandleExtraInfo(OBJECTHANDLE handle);
 
 /*
@@ -101,6 +104,7 @@ void            HndLogSetEvent(OBJECTHANDLE handle, _UNCHECKED_OBJECTREF value);
 /*
  * NON-GC handle enumeration
  */
+GC_DAC_VISIBLE_NO_MANGLE
 void HndEnumHandles(HHANDLETABLE hTable, const uint32_t *puType, uint32_t uTypeCount,
                     HANDLESCANPROC pfnEnum, uintptr_t lParam1, uintptr_t lParam2, bool fAsync);
 
@@ -112,7 +116,7 @@ void HndEnumHandles(HHANDLETABLE hTable, const uint32_t *puType, uint32_t uTypeC
 #define HNDGCF_ASYNC        (0x00000002)    // drop the table lock while scanning
 #define HNDGCF_EXTRAINFO    (0x00000004)    // iterate per-handle data while scanning
 
-
+GC_DAC_VISIBLE_NO_MANGLE
 void            HndScanHandlesForGC(HHANDLETABLE hTable,
                                     HANDLESCANPROC scanProc,
                                     uintptr_t param1,
@@ -168,7 +172,9 @@ BOOL HndFirstAssignHandle(OBJECTHANDLE handle, OBJECTREF objref);
  *       on the VM side.
  *
  */
-FORCEINLINE OBJECTREF HndFetchHandle(OBJECTHANDLE handle)
+GC_DAC_VISIBLE
+FORCEINLINE
+OBJECTREF HndFetchHandle(OBJECTHANDLE handle)
 {
     WRAPPER_NO_CONTRACT;
 
diff --git a/src/gc/handletablepriv.h b/src/gc/handletablepriv.h
index cda1cb08aa..f33a547a23 100644
--- a/src/gc/handletablepriv.h
+++ b/src/gc/handletablepriv.h
@@ -56,9 +56,6 @@
 #define HANDLE_HANDLES_PER_BLOCK    (64)        // segment suballocation granularity
 #define HANDLE_OPTIMIZE_FOR_64_HANDLE_BLOCKS    // flag for certain optimizations
 
-// maximum number of internally supported handle types
-#define HANDLE_MAX_INTERNAL_TYPES   (12)                             // should be a multiple of 4
-
 // number of types allowed for public callers
 #define HANDLE_MAX_PUBLIC_TYPES     (HANDLE_MAX_INTERNAL_TYPES - 1) // reserve one internal type
 
@@ -513,6 +510,11 @@ struct HandleTable
     uint32_t rgTypeFlags[HANDLE_MAX_INTERNAL_TYPES];
 
     /*
+     * per-table AppDomain info
+     */
+    ADIndex uADIndex;
+
+    /*
      * lock for this table
      */
     CrstStatic Lock;
@@ -544,11 +546,6 @@ struct HandleTable
     uint32_t uTableIndex;
 
     /*
-     * per-table AppDomain info
-     */
-    ADIndex uADIndex;
-
-    /*
      * one-level per-type 'quick' handle cache
      */
     OBJECTHANDLE rgQuickCache[HANDLE_MAX_INTERNAL_TYPES];   // interlocked ops used here
diff --git a/src/gc/objecthandle.cpp b/src/gc/objecthandle.cpp
index d7c5d39de5..657050398b 100644
--- a/src/gc/objecthandle.cpp
+++ b/src/gc/objecthandle.cpp
@@ -28,7 +28,7 @@
 #include "nativeoverlapped.h"
 #endif // FEATURE_REDHAWK
 
-GVAL_IMPL(HandleTableMap, g_HandleTableMap);
+HandleTableMap g_HandleTableMap;
 
 // Array of contexts used while scanning dependent handles for promotion. There are as many contexts as GC
 // heaps and they're allocated by Ref_Initialize and initialized during each GC by GcDhInitialScan.
@@ -1894,9 +1894,24 @@ bool HandleTableBucket::Contains(OBJECTHANDLE handle)
 
 #endif // !DACCESS_COMPILE
 
+GC_DAC_VISIBLE
 OBJECTREF GetDependentHandleSecondary(OBJECTHANDLE handle)
 { 
     WRAPPER_NO_CONTRACT;
 
     return UNCHECKED_OBJECTREF_TO_OBJECTREF((_UNCHECKED_OBJECTREF)HndGetHandleExtraInfo(handle));
 }
+
+void PopulateHandleTableDacVars(GcDacVars* gcDacVars)
+{
+    static_assert(offsetof(HandleTableMap, pBuckets) == offsetof(dac_handle_table_map, pBuckets), "handle table map DAC layout mismatch");
+    static_assert(offsetof(HandleTableMap, pNext) == offsetof(dac_handle_table_map, pNext), "handle table map DAC layout mismatch");
+    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);
+#endif // DACCESS_COMPILE
+}
diff --git a/src/gc/objecthandle.h b/src/gc/objecthandle.h
index 6b8bcb70ed..4ed7f2d1a4 100644
--- a/src/gc/objecthandle.h
+++ b/src/gc/objecthandle.h
@@ -32,9 +32,7 @@ struct HandleTableMap
     uint32_t                    dwMaxIndex;
 };
 
-GVAL_DECL(HandleTableMap, g_HandleTableMap);
-
-#define INITIAL_HANDLE_TABLE_ARRAY_SIZE 10
+extern HandleTableMap g_HandleTableMap;
 
 // struct containing g_SystemInfo.dwNumberOfProcessors HHANDLETABLEs and current table index
 // instead of just single HHANDLETABLE for on-fly balancing while adding handles on multiproc machines
@@ -61,6 +59,7 @@ struct HandleTableBucket
                                     (flag == VHT_STRONG)     || \
                                     (flag == VHT_PINNED))
 
+GC_DAC_VISIBLE
 OBJECTREF GetDependentHandleSecondary(OBJECTHANDLE handle);
 
 #ifndef DACCESS_COMPILE
diff --git a/src/inc/dacvars.h b/src/inc/dacvars.h
index 9fe2382d86..affed8af82 100644
--- a/src/inc/dacvars.h
+++ b/src/inc/dacvars.h
@@ -242,7 +242,6 @@ DEFINE_DACVAR(ULONG, SIZE_T, dac__g_runtimeVirtualSize, ::g_runtimeVirtualSize)
 
 DEFINE_DACVAR(ULONG, SyncBlockCache *, SyncBlockCache__s_pSyncBlockCache, SyncBlockCache::s_pSyncBlockCache)
 
-DEFINE_DACVAR(ULONG, HandleTableMap, dac__g_HandleTableMap, ::g_HandleTableMap)
 DEFINE_DACVAR(ULONG, UNKNOWN_POINTER_TYPE, dac__g_pStressLog, ::g_pStressLog)
 
 DEFINE_DACVAR(ULONG, SIZE_T, dac__s_gsCookie, ::s_gsCookie)
diff --git a/src/vm/CMakeLists.txt b/src/vm/CMakeLists.txt
index 8bb2292816..c2cb52e3bd 100644
--- a/src/vm/CMakeLists.txt
+++ b/src/vm/CMakeLists.txt
@@ -124,16 +124,10 @@ set(VM_SOURCES_DAC_AND_WKS_COMMON
 )
 
 set( GC_SOURCES_DAC_AND_WKS_COMMON
-  ../gc/gcconfig.cpp
-  ../gc/gccommon.cpp
-  ../gc/gcscan.cpp
-  ../gc/gcsvr.cpp
-  ../gc/gcwks.cpp
   ../gc/handletable.cpp
   ../gc/handletablecore.cpp
   ../gc/handletablescan.cpp
-  ../gc/objecthandle.cpp
-  ../gc/softwarewritewatch.cpp)
+  ../gc/objecthandle.cpp)
 
 if(FEATURE_READYTORUN)
     list(APPEND VM_SOURCES_DAC_AND_WKS_COMMON
@@ -270,9 +264,15 @@ set(VM_SOURCES_WKS
 
 set(GC_SOURCES_WKS
     ${GC_SOURCES_DAC_AND_WKS_COMMON}
+    ../gc/gcconfig.cpp
+    ../gc/gccommon.cpp
+    ../gc/gcscan.cpp
+    ../gc/gcsvr.cpp
+    ../gc/gcwks.cpp
     ../gc/gchandletable.cpp
     ../gc/gceesvr.cpp
     ../gc/gceewks.cpp
+    ../gc/softwarewritewatch.cpp
     ../gc/handletablecache.cpp)
 
 if(FEATURE_EVENT_TRACE)
diff --git a/src/vm/gchandleutilities.h b/src/vm/gchandleutilities.h
index 762a37b524..08d27141e5 100644
--- a/src/vm/gchandleutilities.h
+++ b/src/vm/gchandleutilities.h
@@ -40,12 +40,13 @@ inline OBJECTREF ObjectFromHandle(OBJECTHANDLE handle)
 {
     _ASSERTE(handle);
 
-#ifdef _DEBUG_IMPL
+#if defined(_DEBUG_IMPL) && !defined(DACCESS_COMPILE)
+    // not allowed to dispatch virtually on a IGCHandleManager when compiling for DAC
     DWORD context = (DWORD)GCHandleUtilities::GetGCHandleManager()->GetHandleContext(handle);
     OBJECTREF objRef = ObjectToOBJECTREF(*(Object**)handle);
 
     ValidateObjectAndAppDomain(objRef, ADIndex(context));
-#endif // _DEBUG_IMPL
+#endif // defined(_DEBUG_IMPL) && !defined(DACCESS_COMPILE)
 
     // Wrap the raw OBJECTREF and return it
     return UNCHECKED_OBJECTREF_TO_OBJECTREF(*PTR_UNCHECKED_OBJECTREF(handle));