Use out-of-proc libunwind to unwind native stack from DAC

Implementation of PAL_VirtualUnwindOutOfProc that uses ptrace libunwind
to be able to unwind native stack in debugee. This allows to get valid managed
stack for threads that passed HelperMethodFrames.

13 files changed, 517 insertions, 99 deletions

diff --git a/src/debug/daccess/dacfn.cpp b/src/debug/daccess/dacfn.cpp
index 1ad5b20ab0..5bec3b4ca1 100644
--- a/src/debug/daccess/dacfn.cpp
+++ b/src/debug/daccess/dacfn.cpp
@@ -218,6 +218,25 @@ DacWriteAll(TADDR addr, PVOID buffer, ULONG32 size, bool throwEx)
     return S_OK;
 }
 
+HRESULT 
+DacGetPid(DWORD *pid)
+{
+    if (!g_dacImpl)
+    {
+        DacError(E_UNEXPECTED);
+        UNREACHABLE();
+    }
+
+    ReleaseHolder<ICorDebugDataTarget4> dt;
+    HRESULT hr = g_dacImpl->m_pTarget->QueryInterface(IID_ICorDebugDataTarget4, (void **)&dt);
+    if (SUCCEEDED(hr))
+    {
+        hr = dt->GetPid(pid);
+    }
+
+    return hr;
+}
+
 // DacAllocVirtual - Allocate memory from the target process
 // Note: this is only available to clients supporting the legacy
 // ICLRDataTarget2 interface.  It's currently used by SOS for notification tables.
diff --git a/src/debug/di/shimdatatarget.cpp b/src/debug/di/shimdatatarget.cpp
index 59f56e798e..d7bfbdc11d 100644
--- a/src/debug/di/shimdatatarget.cpp
+++ b/src/debug/di/shimdatatarget.cpp
@@ -36,6 +36,10 @@ HRESULT STDMETHODCALLTYPE ShimDataTarget::QueryInterface(
     {
         *pInterface = static_cast<ICorDebugMutableDataTarget *>(this);
     }
+    else if (InterfaceId == IID_ICorDebugDataTarget4)
+    {
+        *pInterface = static_cast<ICorDebugDataTarget4 *>(this);
+    }
     else
     {
         *pInterface = NULL;
@@ -71,9 +75,15 @@ ULONG STDMETHODCALLTYPE ShimDataTarget::Release()
 //
 // Return Value: 
 //     The OS PID of the process this data target is representing.
-DWORD ShimDataTarget::GetPid()
+HRESULT STDMETHODCALLTYPE ShimDataTarget::GetPid(DWORD *pdwProcessId)
 {
-    return m_processId;
+    if (pdwProcessId == NULL)  
+    {
+        return E_INVALIDARG;
+    }
+
+    *pdwProcessId = m_processId;
+    return S_OK;
 }
 
 //---------------------------------------------------------------------------------------
diff --git a/src/debug/di/shimdatatarget.h b/src/debug/di/shimdatatarget.h
index 1fabad4778..9e3502bb48 100644
--- a/src/debug/di/shimdatatarget.h
+++ b/src/debug/di/shimdatatarget.h
@@ -21,7 +21,7 @@ typedef HRESULT (*FPContinueStatusChanged)(void * pUserData, DWORD dwThreadId, C
 //---------------------------------------------------------------------------------------
 // Data target for a live process. This is used by Shim. 
 // 
-class ShimDataTarget : public ICorDebugMutableDataTarget
+class ShimDataTarget : public ICorDebugMutableDataTarget, ICorDebugDataTarget4
 {
 public:
     virtual ~ShimDataTarget() {}
@@ -36,9 +36,6 @@ public:
     // is unavailable because it's running
     void SetError(HRESULT hr);
 
-    // Get the OS Process ID that this DataTarget is for.
-    DWORD GetPid();
-
     //
     // IUnknown.
     //
@@ -85,6 +82,13 @@ public:
 
     // @dbgtodo - add Native Patch Table support
 
+    //
+    // ICorDebugDataTarget4
+    //    
+
+    // Get the OS Process ID that this DataTarget is for.
+    virtual HRESULT STDMETHODCALLTYPE GetPid(DWORD *pdwProcessId); 
+
 protected:
     // Pid of the target process.
     DWORD m_processId;
diff --git a/src/debug/di/shimprocess.cpp b/src/debug/di/shimprocess.cpp
index 6e0350b8eb..e4b511abec 100644
--- a/src/debug/di/shimprocess.cpp
+++ b/src/debug/di/shimprocess.cpp
@@ -133,7 +133,9 @@ void ShimProcess::SetProcess(ICorDebugProcess * pProcess)
     if (pProcess != NULL)
     {
         // Verify that DataTarget + new process have the same pid?
-        _ASSERTE(m_pProcess->GetPid() == m_pLiveDataTarget->GetPid());
+        DWORD pid = 0;
+        _ASSERTE(SUCCEEDED(m_pLiveDataTarget->GetPid(&pid)));
+        _ASSERTE(m_pProcess->GetPid() == pid);
     }
 }
 
@@ -738,7 +740,11 @@ HRESULT ShimProcess::HandleWin32DebugEvent(const DEBUG_EVENT * pEvent)
             // This assert could be our only warning of various catastrophic failures in the left-side.
             if (!dwFirstChance && (pRecord->ExceptionCode == STATUS_BREAKPOINT) && !m_fIsInteropDebugging)
             {            
-                DWORD pid = (m_pLiveDataTarget == NULL) ? 0 : m_pLiveDataTarget->GetPid();
+                DWORD pid = 0;
+                if (m_pLiveDataTarget != NULL) 
+                {
+                    m_pLiveDataTarget->GetPid(&pid);
+                }
                 CONSISTENCY_CHECK_MSGF(false, 
                     ("Unhandled breakpoint exception in debuggee (pid=%d (0x%x)) on thread %d(0x%x)\n"
                     "This may mean there was an assert in the debuggee on that thread.\n"
@@ -1742,7 +1748,11 @@ void ShimProcess::PreDispatchEvent(bool fRealCreateProcessEvent /*= false*/)
 CORDB_ADDRESS ShimProcess::GetCLRInstanceBaseAddress()
 {
     CORDB_ADDRESS baseAddress = CORDB_ADDRESS(NULL);
-    DWORD dwPid = m_pLiveDataTarget->GetPid();
+    DWORD dwPid = 0;
+    if (FAILED(m_pLiveDataTarget->GetPid(&dwPid)))
+    {
+        return baseAddress;
+    }
 #if defined(FEATURE_CORESYSTEM)
     // Debugger attaching to CoreCLR via CoreCLRCreateCordbObject should have already specified CLR module address.
     // Code that help to find it now lives in dbgshim.
diff --git a/src/inc/cordebug.idl b/src/inc/cordebug.idl
index 3ba81c32af..f5f975bf26 100644
--- a/src/inc/cordebug.idl
+++ b/src/inc/cordebug.idl
@@ -811,6 +811,24 @@ interface ICorDebugDataTarget3 : IUnknown
 };
 
 /*
+ * Data target that knows how to obtain debugee's process id. 
+ * Debugee is not necessarily a living process at that time or on the same machine.
+ */
+[
+    object,
+    uuid(E799DC06-E099-4713-BDD9-906D3CC02CF2),
+    local,
+    pointer_default(unique)
+]
+interface ICorDebugDataTarget4 : IUnknown
+{
+    /*
+    * gives back a process id
+    */
+    HRESULT GetPid([out] DWORD *pdwProcessId);
+};
+
+/*
  * Mutable extension to the data target.  This version of ICorDebugDataTarget 
  * can be implemented by targets that wish to support modification of the target 
  * process (such as for live invasive debugging).
@@ -879,6 +897,7 @@ interface ICorDebugMutableDataTarget : ICorDebugDataTarget
 
 };
 
+
 /*
  * Interface used by the data access services layer to locate metadata 
  * of assemblies in a target. 
diff --git a/src/inc/daccess.h b/src/inc/daccess.h
index 704a1ea425..241c25ea21 100644
--- a/src/inc/daccess.h
+++ b/src/inc/daccess.h
@@ -663,6 +663,7 @@ HRESULT DacFreeVirtual(TADDR mem, ULONG32 size, ULONG32 typeFlags,
 PVOID   DacInstantiateTypeByAddress(TADDR addr, ULONG32 size, bool throwEx);
 PVOID   DacInstantiateTypeByAddressNoReport(TADDR addr, ULONG32 size, bool throwEx);
 PVOID   DacInstantiateClassByVTable(TADDR addr, ULONG32 minSize, bool throwEx);
+HRESULT DacGetPid(DWORD *pid);
 
 // Copy a null-terminated ascii or unicode string from the target to the host.
 // Note that most of the work here is to find the null terminator.  If you know the exact length,
diff --git a/src/pal/inc/pal.h b/src/pal/inc/pal.h
index 43fc0694f5..4ed5e9267e 100644
--- a/src/pal/inc/pal.h
+++ b/src/pal/inc/pal.h
@@ -3442,6 +3442,15 @@ size_t
 PALAPI
 PAL_GetLogicalProcessorCacheSizeFromOS();
 
+typedef BOOL (*ReadMemoryWordCallback)(SIZE_T address, SIZE_T *value);
+
+PALIMPORT BOOL PALAPI PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextPointers);
+
+PALIMPORT BOOL PALAPI PAL_VirtualUnwindOutOfProc(CONTEXT *context, 
+                                                 KNONVOLATILE_CONTEXT_POINTERS *contextPointers, 
+                                                 DWORD pid, 
+                                                 ReadMemoryWordCallback readMemCallback);
+
 #define GetLogicalProcessorCacheSizeFromOS PAL_GetLogicalProcessorCacheSizeFromOS
 
 #ifdef PLATFORM_UNIX
diff --git a/src/pal/inc/rt/palrt.h b/src/pal/inc/rt/palrt.h
index 7f3cdbdc14..2d67e108b3 100644
--- a/src/pal/inc/rt/palrt.h
+++ b/src/pal/inc/rt/palrt.h
@@ -1710,8 +1710,6 @@ typedef LONG (WINAPI *PTOP_LEVEL_EXCEPTION_FILTER)(
     );
 typedef PTOP_LEVEL_EXCEPTION_FILTER LPTOP_LEVEL_EXCEPTION_FILTER;
 
-BOOL PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextPointers);
-
 /******************* ntdef ************************************/
 
 #ifndef ANYSIZE_ARRAY
diff --git a/src/pal/prebuilt/idl/cordebug_i.c b/src/pal/prebuilt/idl/cordebug_i.c
index 2b8b1f5c02..8a947ccf49 100644
--- a/src/pal/prebuilt/idl/cordebug_i.c
+++ b/src/pal/prebuilt/idl/cordebug_i.c
@@ -98,6 +98,9 @@ MIDL_DEFINE_GUID(IID, IID_ICorDebugLoadedModule,0x817F343A,0x6630,0x4578,0x96,0x
 MIDL_DEFINE_GUID(IID, IID_ICorDebugDataTarget3,0xD05E60C3,0x848C,0x4E7D,0x89,0x4E,0x62,0x33,0x20,0xFF,0x6A,0xFA);
 
 
+MIDL_DEFINE_GUID(IID, IID_ICorDebugDataTarget4,0xE799DC06,0xE099,0x4713,0xBD,0xD9,0x90,0x6D,0x3C,0xC0,0x2C,0xF2);
+
+
 MIDL_DEFINE_GUID(IID, IID_ICorDebugMutableDataTarget,0xA1B8A756,0x3CB6,0x4CCB,0x97,0x9F,0x3D,0xF9,0x99,0x67,0x3A,0x59);
 
 
diff --git a/src/pal/prebuilt/inc/cordebug.h b/src/pal/prebuilt/inc/cordebug.h
index db8bf6d24d..153d3901ee 100644
--- a/src/pal/prebuilt/inc/cordebug.h
+++ b/src/pal/prebuilt/inc/cordebug.h
@@ -122,6 +122,13 @@ typedef interface ICorDebugDataTarget3 ICorDebugDataTarget3;
 #endif 	/* __ICorDebugDataTarget3_FWD_DEFINED__ */
 
 
+#ifndef __ICorDebugDataTarget4_FWD_DEFINED__
+#define __ICorDebugDataTarget4_FWD_DEFINED__
+typedef interface ICorDebugDataTarget4 ICorDebugDataTarget4;
+
+#endif 	/* __ICorDebugDataTarget4_FWD_DEFINED__ */
+
+
 #ifndef __ICorDebugMutableDataTarget_FWD_DEFINED__
 #define __ICorDebugMutableDataTarget_FWD_DEFINED__
 typedef interface ICorDebugMutableDataTarget ICorDebugMutableDataTarget;
@@ -2831,6 +2838,86 @@ EXTERN_C const IID IID_ICorDebugDataTarget3;
 #endif 	/* __ICorDebugDataTarget3_INTERFACE_DEFINED__ */
 
 
+#ifndef __ICorDebugDataTarget4_INTERFACE_DEFINED__
+#define __ICorDebugDataTarget4_INTERFACE_DEFINED__
+
+/* interface ICorDebugDataTarget4 */
+/* [unique][local][uuid][object] */ 
+
+
+EXTERN_C const IID IID_ICorDebugDataTarget4;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+    
+    MIDL_INTERFACE("E799DC06-E099-4713-BDD9-906D3CC02CF2")
+    ICorDebugDataTarget4 : public IUnknown
+    {
+    public:
+        virtual HRESULT STDMETHODCALLTYPE GetPid( 
+            /* [out] */ DWORD *pdwProcessId) = 0;
+        
+    };
+    
+    
+#else 	/* C style interface */
+
+    typedef struct ICorDebugDataTarget4Vtbl
+    {
+        BEGIN_INTERFACE
+        
+        HRESULT ( STDMETHODCALLTYPE *QueryInterface )( 
+            ICorDebugDataTarget4 * This,
+            /* [in] */ REFIID riid,
+            /* [annotation][iid_is][out] */ 
+            _COM_Outptr_  void **ppvObject);
+        
+        ULONG ( STDMETHODCALLTYPE *AddRef )( 
+            ICorDebugDataTarget4 * This);
+        
+        ULONG ( STDMETHODCALLTYPE *Release )( 
+            ICorDebugDataTarget4 * This);
+        
+        HRESULT ( STDMETHODCALLTYPE *GetPid )( 
+            ICorDebugDataTarget4 * This,
+            /* [out] */ DWORD *pdwProcessId);
+        
+        END_INTERFACE
+    } ICorDebugDataTarget4Vtbl;
+
+    interface ICorDebugDataTarget4
+    {
+        CONST_VTBL struct ICorDebugDataTarget4Vtbl *lpVtbl;
+    };
+
+    
+
+#ifdef COBJMACROS
+
+
+#define ICorDebugDataTarget4_QueryInterface(This,riid,ppvObject)	\
+    ( (This)->lpVtbl -> QueryInterface(This,riid,ppvObject) ) 
+
+#define ICorDebugDataTarget4_AddRef(This)	\
+    ( (This)->lpVtbl -> AddRef(This) ) 
+
+#define ICorDebugDataTarget4_Release(This)	\
+    ( (This)->lpVtbl -> Release(This) ) 
+
+
+#define ICorDebugDataTarget4_GetPid(This,pdwProcessId)	\
+    ( (This)->lpVtbl -> GetPid(This,pdwProcessId) ) 
+
+#endif /* COBJMACROS */
+
+
+#endif 	/* C style interface */
+
+
+
+
+#endif 	/* __ICorDebugDataTarget4_INTERFACE_DEFINED__ */
+
+
 #ifndef __ICorDebugMutableDataTarget_INTERFACE_DEFINED__
 #define __ICorDebugMutableDataTarget_INTERFACE_DEFINED__
 
@@ -3063,15 +3150,15 @@ EXTERN_C const IID IID_ICorDebugMetaDataLocator;
 #endif 	/* __ICorDebugMetaDataLocator_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0014 */
+/* interface __MIDL_itf_cordebug_0000_0015 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0014_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0014_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0015_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0015_v0_0_s_ifspec;
 
 #ifndef __ICorDebugManagedCallback_INTERFACE_DEFINED__
 #define __ICorDebugManagedCallback_INTERFACE_DEFINED__
@@ -3525,15 +3612,15 @@ EXTERN_C const IID IID_ICorDebugManagedCallback;
 #endif 	/* __ICorDebugManagedCallback_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0015 */
+/* interface __MIDL_itf_cordebug_0000_0016 */
 /* [local] */ 
 
 #pragma warning(pop)
 #pragma warning(push)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0015_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0015_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0016_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0016_v0_0_s_ifspec;
 
 #ifndef __ICorDebugManagedCallback3_INTERFACE_DEFINED__
 #define __ICorDebugManagedCallback3_INTERFACE_DEFINED__
@@ -3617,14 +3704,14 @@ EXTERN_C const IID IID_ICorDebugManagedCallback3;
 #endif 	/* __ICorDebugManagedCallback3_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0016 */
+/* interface __MIDL_itf_cordebug_0000_0017 */
 /* [local] */ 
 
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0016_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0016_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0017_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0017_v0_0_s_ifspec;
 
 #ifndef __ICorDebugManagedCallback2_INTERFACE_DEFINED__
 #define __ICorDebugManagedCallback2_INTERFACE_DEFINED__
@@ -3839,14 +3926,14 @@ EXTERN_C const IID IID_ICorDebugManagedCallback2;
 #endif 	/* __ICorDebugManagedCallback2_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0017 */
+/* interface __MIDL_itf_cordebug_0000_0018 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0017_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0017_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0018_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0018_v0_0_s_ifspec;
 
 #ifndef __ICorDebugUnmanagedCallback_INTERFACE_DEFINED__
 #define __ICorDebugUnmanagedCallback_INTERFACE_DEFINED__
@@ -3930,7 +4017,7 @@ EXTERN_C const IID IID_ICorDebugUnmanagedCallback;
 #endif 	/* __ICorDebugUnmanagedCallback_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0018 */
+/* interface __MIDL_itf_cordebug_0000_0019 */
 /* [local] */ 
 
 typedef 
@@ -3950,8 +4037,8 @@ enum CorDebugHandleType
 #pragma warning(disable:28718) 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0018_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0018_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0019_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0019_v0_0_s_ifspec;
 
 #ifndef __ICorDebug_INTERFACE_DEFINED__
 #define __ICorDebug_INTERFACE_DEFINED__
@@ -4139,14 +4226,14 @@ EXTERN_C const IID IID_ICorDebug;
 #endif 	/* __ICorDebug_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0019 */
+/* interface __MIDL_itf_cordebug_0000_0020 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0019_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0019_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0020_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0020_v0_0_s_ifspec;
 
 #ifndef __ICorDebugRemoteTarget_INTERFACE_DEFINED__
 #define __ICorDebugRemoteTarget_INTERFACE_DEFINED__
@@ -4358,7 +4445,7 @@ EXTERN_C const IID IID_ICorDebugRemote;
 #endif 	/* __ICorDebugRemote_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0021 */
+/* interface __MIDL_itf_cordebug_0000_0022 */
 /* [local] */ 
 
 typedef struct _COR_VERSION
@@ -4371,8 +4458,8 @@ typedef struct _COR_VERSION
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0021_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0021_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0022_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0022_v0_0_s_ifspec;
 
 #ifndef __ICorDebug2_INTERFACE_DEFINED__
 #define __ICorDebug2_INTERFACE_DEFINED__
@@ -4534,7 +4621,7 @@ EXTERN_C const IID IID_ICorDebug2;
 #endif 	/* __ICorDebug2_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0022 */
+/* interface __MIDL_itf_cordebug_0000_0023 */
 /* [local] */ 
 
 typedef 
@@ -4546,8 +4633,8 @@ enum CorDebugThreadState
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0022_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0022_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0023_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0023_v0_0_s_ifspec;
 
 #ifndef __ICorDebugController_INTERFACE_DEFINED__
 #define __ICorDebugController_INTERFACE_DEFINED__
@@ -4729,15 +4816,15 @@ EXTERN_C const IID IID_ICorDebugController;
 #endif 	/* __ICorDebugController_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0023 */
+/* interface __MIDL_itf_cordebug_0000_0024 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0023_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0023_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0024_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0024_v0_0_s_ifspec;
 
 #ifndef __ICorDebugAppDomain_INTERFACE_DEFINED__
 #define __ICorDebugAppDomain_INTERFACE_DEFINED__
@@ -4989,14 +5076,14 @@ EXTERN_C const IID IID_ICorDebugAppDomain;
 #endif 	/* __ICorDebugAppDomain_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0024 */
+/* interface __MIDL_itf_cordebug_0000_0025 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0024_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0024_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0025_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0025_v0_0_s_ifspec;
 
 #ifndef __ICorDebugAppDomain2_INTERFACE_DEFINED__
 #define __ICorDebugAppDomain2_INTERFACE_DEFINED__
@@ -5494,15 +5581,15 @@ EXTERN_C const IID IID_ICorDebugAppDomain4;
 #endif 	/* __ICorDebugAppDomain4_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0028 */
+/* interface __MIDL_itf_cordebug_0000_0029 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0028_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0028_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0029_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0029_v0_0_s_ifspec;
 
 #ifndef __ICorDebugAssembly_INTERFACE_DEFINED__
 #define __ICorDebugAssembly_INTERFACE_DEFINED__
@@ -5632,14 +5719,14 @@ EXTERN_C const IID IID_ICorDebugAssembly;
 #endif 	/* __ICorDebugAssembly_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0029 */
+/* interface __MIDL_itf_cordebug_0000_0030 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0029_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0029_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0030_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0030_v0_0_s_ifspec;
 
 #ifndef __ICorDebugAssembly2_INTERFACE_DEFINED__
 #define __ICorDebugAssembly2_INTERFACE_DEFINED__
@@ -5811,7 +5898,7 @@ EXTERN_C const IID IID_ICorDebugAssembly3;
 #endif 	/* __ICorDebugAssembly3_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0031 */
+/* interface __MIDL_itf_cordebug_0000_0032 */
 /* [local] */ 
 
 #ifndef _DEF_COR_TYPEID_
@@ -5832,8 +5919,8 @@ typedef struct _COR_HEAPOBJECT
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0031_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0031_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0032_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0032_v0_0_s_ifspec;
 
 #ifndef __ICorDebugHeapEnum_INTERFACE_DEFINED__
 #define __ICorDebugHeapEnum_INTERFACE_DEFINED__
@@ -5947,7 +6034,7 @@ EXTERN_C const IID IID_ICorDebugHeapEnum;
 #endif 	/* __ICorDebugHeapEnum_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0032 */
+/* interface __MIDL_itf_cordebug_0000_0033 */
 /* [local] */ 
 
 typedef 
@@ -5985,8 +6072,8 @@ typedef struct _COR_HEAPINFO
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0032_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0032_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0033_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0033_v0_0_s_ifspec;
 
 #ifndef __ICorDebugHeapSegmentEnum_INTERFACE_DEFINED__
 #define __ICorDebugHeapSegmentEnum_INTERFACE_DEFINED__
@@ -6100,7 +6187,7 @@ EXTERN_C const IID IID_ICorDebugHeapSegmentEnum;
 #endif 	/* __ICorDebugHeapSegmentEnum_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0033 */
+/* interface __MIDL_itf_cordebug_0000_0034 */
 /* [local] */ 
 
 typedef 
@@ -6136,8 +6223,8 @@ typedef struct COR_GC_REFERENCE
 #endif // _DEF_COR_GC_REFERENCE_
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0033_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0033_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0034_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0034_v0_0_s_ifspec;
 
 #ifndef __ICorDebugGCReferenceEnum_INTERFACE_DEFINED__
 #define __ICorDebugGCReferenceEnum_INTERFACE_DEFINED__
@@ -6251,7 +6338,7 @@ EXTERN_C const IID IID_ICorDebugGCReferenceEnum;
 #endif 	/* __ICorDebugGCReferenceEnum_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0034 */
+/* interface __MIDL_itf_cordebug_0000_0035 */
 /* [local] */ 
 
 #ifndef _DEF_COR_ARRAY_LAYOUT_
@@ -6296,8 +6383,8 @@ typedef struct COR_FIELD
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0034_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0034_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0035_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0035_v0_0_s_ifspec;
 
 #ifndef __ICorDebugProcess_INTERFACE_DEFINED__
 #define __ICorDebugProcess_INTERFACE_DEFINED__
@@ -6647,14 +6734,14 @@ EXTERN_C const IID IID_ICorDebugProcess;
 #endif 	/* __ICorDebugProcess_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0035 */
+/* interface __MIDL_itf_cordebug_0000_0036 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0035_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0035_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0036_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0036_v0_0_s_ifspec;
 
 #ifndef __ICorDebugProcess2_INTERFACE_DEFINED__
 #define __ICorDebugProcess2_INTERFACE_DEFINED__
@@ -7098,7 +7185,7 @@ EXTERN_C const IID IID_ICorDebugProcess5;
 #endif 	/* __ICorDebugProcess5_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0038 */
+/* interface __MIDL_itf_cordebug_0000_0039 */
 /* [local] */ 
 
 typedef 
@@ -7134,8 +7221,8 @@ enum CorDebugStateChange
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0038_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0038_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0039_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0039_v0_0_s_ifspec;
 
 #ifndef __ICorDebugDebugEvent_INTERFACE_DEFINED__
 #define __ICorDebugDebugEvent_INTERFACE_DEFINED__
@@ -7227,7 +7314,7 @@ EXTERN_C const IID IID_ICorDebugDebugEvent;
 #endif 	/* __ICorDebugDebugEvent_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0039 */
+/* interface __MIDL_itf_cordebug_0000_0040 */
 /* [local] */ 
 
 typedef 
@@ -7249,8 +7336,8 @@ enum CorDebugCodeInvokePurpose
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0039_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0039_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0040_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0040_v0_0_s_ifspec;
 
 #ifndef __ICorDebugProcess6_INTERFACE_DEFINED__
 #define __ICorDebugProcess6_INTERFACE_DEFINED__
@@ -7398,7 +7485,7 @@ EXTERN_C const IID IID_ICorDebugProcess6;
 #endif 	/* __ICorDebugProcess6_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0040 */
+/* interface __MIDL_itf_cordebug_0000_0041 */
 /* [local] */ 
 
 typedef 
@@ -7410,8 +7497,8 @@ enum WriteableMetadataUpdateMode
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0040_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0040_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0041_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0041_v0_0_s_ifspec;
 
 #ifndef __ICorDebugProcess7_INTERFACE_DEFINED__
 #define __ICorDebugProcess7_INTERFACE_DEFINED__
@@ -10493,7 +10580,7 @@ EXTERN_C const IID IID_ICorDebugILFrame3;
 #endif 	/* __ICorDebugILFrame3_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0064 */
+/* interface __MIDL_itf_cordebug_0000_0065 */
 /* [local] */ 
 
 typedef 
@@ -10505,8 +10592,8 @@ enum ILCodeKind
 
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0064_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0064_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0065_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0065_v0_0_s_ifspec;
 
 #ifndef __ICorDebugILFrame4_INTERFACE_DEFINED__
 #define __ICorDebugILFrame4_INTERFACE_DEFINED__
@@ -10870,15 +10957,15 @@ EXTERN_C const IID IID_ICorDebugNativeFrame;
 #endif 	/* __ICorDebugNativeFrame_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0066 */
+/* interface __MIDL_itf_cordebug_0000_0067 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0066_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0066_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0067_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0067_v0_0_s_ifspec;
 
 #ifndef __ICorDebugNativeFrame2_INTERFACE_DEFINED__
 #define __ICorDebugNativeFrame2_INTERFACE_DEFINED__
@@ -11448,14 +11535,14 @@ EXTERN_C const IID IID_ICorDebugModule;
 #endif 	/* __ICorDebugModule_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0070 */
+/* interface __MIDL_itf_cordebug_0000_0071 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0070_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0070_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0071_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0071_v0_0_s_ifspec;
 
 #ifndef __ICorDebugModule2_INTERFACE_DEFINED__
 #define __ICorDebugModule2_INTERFACE_DEFINED__
@@ -14252,15 +14339,15 @@ EXTERN_C const IID IID_ICorDebugBoxValue;
 #endif 	/* __ICorDebugBoxValue_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0094 */
+/* interface __MIDL_itf_cordebug_0000_0095 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0094_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0094_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0095_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0095_v0_0_s_ifspec;
 
 #ifndef __ICorDebugStringValue_INTERFACE_DEFINED__
 #define __ICorDebugStringValue_INTERFACE_DEFINED__
@@ -14400,14 +14487,14 @@ EXTERN_C const IID IID_ICorDebugStringValue;
 #endif 	/* __ICorDebugStringValue_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0095 */
+/* interface __MIDL_itf_cordebug_0000_0096 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0095_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0095_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0096_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0096_v0_0_s_ifspec;
 
 #ifndef __ICorDebugArrayValue_INTERFACE_DEFINED__
 #define __ICorDebugArrayValue_INTERFACE_DEFINED__
@@ -16840,15 +16927,15 @@ EXTERN_C const IID IID_ICorDebugBlockingObjectEnum;
 #endif 	/* __ICorDebugBlockingObjectEnum_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0116 */
+/* interface __MIDL_itf_cordebug_0000_0117 */
 /* [local] */ 
 
 #pragma warning(push)
 #pragma warning(disable:28718)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0116_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0116_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0117_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0117_v0_0_s_ifspec;
 
 #ifndef __ICorDebugMDA_INTERFACE_DEFINED__
 #define __ICorDebugMDA_INTERFACE_DEFINED__
@@ -16988,7 +17075,7 @@ EXTERN_C const IID IID_ICorDebugMDA;
 #endif 	/* __ICorDebugMDA_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0117 */
+/* interface __MIDL_itf_cordebug_0000_0118 */
 /* [local] */ 
 
 #pragma warning(pop)
@@ -16996,8 +17083,8 @@ EXTERN_C const IID IID_ICorDebugMDA;
 #pragma warning(disable:28718)	
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0117_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0117_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0118_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0118_v0_0_s_ifspec;
 
 #ifndef __ICorDebugEditAndContinueErrorInfo_INTERFACE_DEFINED__
 #define __ICorDebugEditAndContinueErrorInfo_INTERFACE_DEFINED__
@@ -17113,14 +17200,14 @@ EXTERN_C const IID IID_ICorDebugEditAndContinueErrorInfo;
 #endif 	/* __ICorDebugEditAndContinueErrorInfo_INTERFACE_DEFINED__ */
 
 
-/* interface __MIDL_itf_cordebug_0000_0118 */
+/* interface __MIDL_itf_cordebug_0000_0119 */
 /* [local] */ 
 
 #pragma warning(pop)
 
 
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0118_v0_0_c_ifspec;
-extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0118_v0_0_s_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0119_v0_0_c_ifspec;
+extern RPC_IF_HANDLE __MIDL_itf_cordebug_0000_0119_v0_0_s_ifspec;
 
 #ifndef __ICorDebugEditAndContinueSnapshot_INTERFACE_DEFINED__
 #define __ICorDebugEditAndContinueSnapshot_INTERFACE_DEFINED__
diff --git a/src/pal/src/CMakeLists.txt b/src/pal/src/CMakeLists.txt
index ce364b3c64..c814e10aac 100644
--- a/src/pal/src/CMakeLists.txt
+++ b/src/pal/src/CMakeLists.txt
@@ -207,6 +207,13 @@ if(CMAKE_SYSTEM_NAME STREQUAL Linux)
   if(PAL_CMAKE_PLATFORM_ARCH_ARM)
     target_link_libraries(coreclrpal
       gcc_s
+      unwind-arm
+    )
+  endif()
+
+  if(PAL_CMAKE_PLATFORM_ARCH_AMD64)
+    target_link_libraries(coreclrpal
+      unwind-x86_64
     )
   endif()
     
@@ -215,6 +222,8 @@ if(CMAKE_SYSTEM_NAME STREQUAL Linux)
     rt
     dl
     unwind
+    unwind-ptrace
+    unwind-generic
   )
 endif(CMAKE_SYSTEM_NAME STREQUAL Linux)
 
diff --git a/src/pal/src/exception/seh-unwind.cpp b/src/pal/src/exception/seh-unwind.cpp
index 465c459dda..cf899f7f7f 100644
--- a/src/pal/src/exception/seh-unwind.cpp
+++ b/src/pal/src/exception/seh-unwind.cpp
@@ -26,12 +26,20 @@ Abstract:
 #endif // !FEATURE_PAL_SXS
 
 #include "pal/context.h"
+#include "pal.h"
 #include <dlfcn.h>
 #include <exception>
+    
 #if HAVE_LIBUNWIND_H
+#ifndef __LINUX__
 #define UNW_LOCAL_ONLY
+#endif // !__LINUX__       
 #include <libunwind.h>
-#endif
+#ifdef __LINUX__
+#include <libunwind-ptrace.h>
+#endif // __LINUX__    
+#endif // HAVE_LIBUNWIND_H
+
 
 //----------------------------------------------------------------------
 // Virtual Unwinding
@@ -226,6 +234,7 @@ BOOL PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextP
     int st;
     unw_context_t unwContext;
     unw_cursor_t cursor;
+
 #if defined(__APPLE__) || defined(__FreeBSD__) || defined(_ARM64_)
     DWORD64 curPc;
 #endif
@@ -251,7 +260,6 @@ BOOL PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextP
         return FALSE;
     }
 #endif
-
     st = unw_init_local(&cursor, &unwContext);
     if (st < 0)
     {
@@ -308,13 +316,230 @@ BOOL PAL_VirtualUnwind(CONTEXT *context, KNONVOLATILE_CONTEXT_POINTERS *contextP
     {
         GetContextPointers(&cursor, &unwContext, contextPointers);
     }
-
     return TRUE;
 }
+
 #else
 #error don't know how to unwind on this platform
 #endif
 
+
+#ifdef __LINUX__
+
+
+static struct LibunwindCallbacksInfoType
+{
+     CONTEXT *Context;
+     ReadMemoryWordCallback readMemCallback;
+} LibunwindCallbacksInfo;
+
+static int get_dyn_info_list_addr(unw_addr_space_t as, unw_word_t *dilap, void *arg)
+{
+    return -UNW_ENOINFO;
+}
+
+static int access_mem(unw_addr_space_t as, unw_word_t addr, unw_word_t *valp, int write, void *arg)
+{
+    if (write)
+    {
+        ASSERT("Memory write must never be called by libunwind during stackwalk");
+        return -UNW_EINVAL;
+    }
+
+    // access_mem sometimes gets called by _UPT_find_proc_info, in such cases arg has a pointer to libunwind internal data
+    // returned by _UPT_create. It makes it impossible to use arg for passing readMemCallback. That's why we have to use global variable.
+    if (LibunwindCallbacksInfo.readMemCallback((SIZE_T)addr, (SIZE_T *)valp))
+    {
+        return UNW_ESUCCESS;
+    }
+    else 
+    {
+        return -UNW_EUNSPEC;
+    }
+}
+
+static int access_reg(unw_addr_space_t as, unw_regnum_t regnum, unw_word_t *valp, int write, void *arg)
+{
+    if (write)
+    {
+        ASSERT("Register write must never be called by libunwind during stackwalk");
+        return -UNW_EREADONLYREG;
+    }
+
+    CONTEXT *winContext = LibunwindCallbacksInfo.Context;
+
+    switch (regnum) 
+    {
+#if defined(_AMD64_)
+        case UNW_REG_IP:       *valp = (unw_word_t) winContext->Rip; break;
+        case UNW_REG_SP:       *valp = (unw_word_t) winContext->Rsp; break;
+        case UNW_X86_64_RBP:   *valp = (unw_word_t) winContext->Rbp; break;
+        case UNW_X86_64_RBX:   *valp = (unw_word_t) winContext->Rbx; break;
+        case UNW_X86_64_R12:   *valp = (unw_word_t) winContext->R12; break;
+        case UNW_X86_64_R13:   *valp = (unw_word_t) winContext->R13; break;
+        case UNW_X86_64_R14:   *valp = (unw_word_t) winContext->R14; break;
+        case UNW_X86_64_R15:   *valp = (unw_word_t) winContext->R15; break;
+#elif defined(_ARM_)
+        case UNW_ARM_R13:      *valp = (unw_word_t) winContext->Sp; break;
+        case UNW_ARM_R14:      *valp = (unw_word_t) winContext->Lr; break;
+        case UNW_ARM_R15:      *valp = (unw_word_t) winContext->Pc; break;
+        case UNW_ARM_R4:       *valp = (unw_word_t) winContext->R4; break;
+        case UNW_ARM_R5:       *valp = (unw_word_t) winContext->R5; break;
+        case UNW_ARM_R6:       *valp = (unw_word_t) winContext->R6; break;
+        case UNW_ARM_R7:       *valp = (unw_word_t) winContext->R7; break;
+        case UNW_ARM_R8:       *valp = (unw_word_t) winContext->R8; break;
+        case UNW_ARM_R9:       *valp = (unw_word_t) winContext->R9; break;
+        case UNW_ARM_R10:      *valp = (unw_word_t) winContext->R10; break;
+        case UNW_ARM_R11:      *valp = (unw_word_t) winContext->R11; break;
+#elif defined(_ARM64_)
+        case UNW_REG_IP:       *valp = (unw_word_t) winContext->Pc; break;
+        case UNW_REG_SP:       *valp = (unw_word_t) winContext->Sp; break;
+        case UNW_AARCH64_X29:  *valp = (unw_word_t) winContext->Fp; break;
+        case UNW_AARCH64_X30:  *valp = (unw_word_t) winContext->Lr; break;
+        case UNW_AARCH64_X19:  *valp = (unw_word_t) winContext->X19; break;
+        case UNW_AARCH64_X20:  *valp = (unw_word_t) winContext->X20; break;
+        case UNW_AARCH64_X21:  *valp = (unw_word_t) winContext->X21; break;
+        case UNW_AARCH64_X22:  *valp = (unw_word_t) winContext->X22; break;
+        case UNW_AARCH64_X23:  *valp = (unw_word_t) winContext->X23; break;
+        case UNW_AARCH64_X24:  *valp = (unw_word_t) winContext->X24; break;
+        case UNW_AARCH64_X25:  *valp = (unw_word_t) winContext->X25; break;
+        case UNW_AARCH64_X26:  *valp = (unw_word_t) winContext->X26; break;
+        case UNW_AARCH64_X27:  *valp = (unw_word_t) winContext->X27; break;
+        case UNW_AARCH64_X28:  *valp = (unw_word_t) winContext->X28; break;
+#else
+#error unsupported architecture
+#endif
+        default:
+            ASSERT("Attempt to read an unknown register.");
+            return -UNW_EBADREG;
+    }
+    return UNW_ESUCCESS;
+}
+
+static int access_fpreg(unw_addr_space_t as, unw_regnum_t regnum, unw_fpreg_t *fpvalp, int write, void *arg)
+{
+    ASSERT("Not supposed to be ever called");
+    return -UNW_EINVAL;
+}
+
+static int resume(unw_addr_space_t as, unw_cursor_t *cp, void *arg)
+{
+    ASSERT("Not supposed to be ever called");
+    return -UNW_EINVAL;
+}
+
+static int get_proc_name(unw_addr_space_t as, unw_word_t addr, char *bufp, size_t buf_len, unw_word_t *offp, void *arg)
+{
+    ASSERT("Not supposed to be ever called");
+    return -UNW_EINVAL;  
+}
+
+static unw_accessors_t unwind_accessors =
+{
+    .find_proc_info = _UPT_find_proc_info,
+    .put_unwind_info = _UPT_put_unwind_info,
+    .get_dyn_info_list_addr = get_dyn_info_list_addr,
+    .access_mem = access_mem,
+    .access_reg = access_reg,
+    .access_fpreg = access_fpreg,
+    .resume = resume,
+    .get_proc_name = get_proc_name
+};
+
+BOOL PAL_VirtualUnwindOutOfProc(CONTEXT *context, 
+                                KNONVOLATILE_CONTEXT_POINTERS *contextPointers, 
+                                DWORD pid, 
+                                ReadMemoryWordCallback readMemCallback)
+{
+    // This function can be executed only by one thread at a time. 
+    // The reason for this is that we need to pass context and read mem function to libunwind callbacks
+    // but "arg" is already used by the pointer returned from _UPT_create(). 
+    // So we resort to using global variables and a lock.
+    struct Lock 
+    {
+        CRITICAL_SECTION cs;
+        Lock()
+        {        
+            // ctor of a static variable is a thread-safe way to initialize critical section exactly once (clang,gcc)
+            InitializeCriticalSection(&cs);
+        }
+    };
+    struct LockHolder
+    {
+        CRITICAL_SECTION *cs;
+        LockHolder(CRITICAL_SECTION *cs)
+        {
+            this->cs = cs;
+            EnterCriticalSection(cs);
+        }
+
+        ~LockHolder()
+        {
+            LeaveCriticalSection(cs);
+            cs = NULL;
+        }
+    };    
+    static Lock lock;
+    LockHolder lockHolder(&lock.cs);
+
+    int st;
+    unw_context_t unwContext;
+    unw_cursor_t cursor;
+    unw_addr_space_t addrSpace = 0;
+    void *libunwindUptPtr = NULL;
+    BOOL result = FALSE;
+
+    LibunwindCallbacksInfo.Context = context;
+    LibunwindCallbacksInfo.readMemCallback = readMemCallback;
+    WinContextToUnwindContext(context, &unwContext);
+    addrSpace = unw_create_addr_space(&unwind_accessors, 0);
+    libunwindUptPtr = _UPT_create(pid);
+    st = unw_init_remote(&cursor, addrSpace, libunwindUptPtr);
+    if (st < 0)
+    {
+        result = FALSE;
+        goto Exit;
+    }
+
+    st = unw_step(&cursor);
+    if (st < 0)
+    {
+        result = FALSE;
+        goto Exit;
+    }
+
+    UnwindContextToWinContext(&cursor, context);
+
+    if (contextPointers != NULL)
+    {
+        GetContextPointers(&cursor, &unwContext, contextPointers);
+    }
+    result = TRUE;
+
+Exit:
+    if (libunwindUptPtr != nullptr) 
+    {
+        _UPT_destroy(libunwindUptPtr);
+    }
+    if (addrSpace != 0) 
+    {
+        unw_destroy_addr_space(addrSpace);
+    }    
+    return result;
+}
+#else // __LINUX__
+
+BOOL PAL_VirtualUnwindOutOfProc(CONTEXT *context, 
+                                KNONVOLATILE_CONTEXT_POINTERS *contextPointers, 
+                                DWORD pid, 
+                                ReadMemoryWordCallback readMemCallback)
+{
+    //UNIXTODO: Implement for Mac flavor of libunwind
+    return FALSE;
+}
+
+#endif // !__LINUX__
+
 /*++
 Function:
     RtlpRaiseException
diff --git a/src/vm/amd64/gmsamd64.cpp b/src/vm/amd64/gmsamd64.cpp
index 197e8fde24..49f45c96e5 100644
--- a/src/vm/amd64/gmsamd64.cpp
+++ b/src/vm/amd64/gmsamd64.cpp
@@ -10,7 +10,13 @@
 #include "common.h"
 #include "gmscpu.h"
 
-
+#if defined(DACCESS_COMPILE)
+static BOOL DacReadAllAdapter(SIZE_T address, SIZE_T *value)
+{
+    HRESULT hr = DacReadAll((TADDR)address, (PVOID)value, sizeof(*value), false);
+    return SUCCEEDED(hr);
+}
+#endif //DACCESS_COMPILE
 
 void LazyMachState::unwindLazyState(LazyMachState* baseState,
                                     MachState* unwoundState,
@@ -56,7 +62,25 @@ void LazyMachState::unwindLazyState(LazyMachState* baseState,
 #ifndef FEATURE_PAL
         pvControlPc = Thread::VirtualUnwindCallFrame(&ctx, &nonVolRegPtrs);
 #else // !FEATURE_PAL
+        
+#if defined(DACCESS_COMPILE)
+        DWORD pid;
+        HRESULT hr = DacGetPid(&pid);
+        if (SUCCEEDED(hr))
+        {
+            if (!PAL_VirtualUnwindOutOfProc(&ctx, &nonVolRegPtrs, pid, DacReadAllAdapter))
+            {
+                DacError(E_FAIL);   
+            }
+        } 
+        else 
+        {
+            DacError(hr);
+        }
+#else
         PAL_VirtualUnwind(&ctx, &nonVolRegPtrs);
+#endif  // DACCESS_COMPILE    
+
         pvControlPc = GetIP(&ctx);
 #endif // !FEATURE_PAL