1 files changed, 144 insertions, 0 deletions
diff --git a/src/vm/arm/exceparm.cpp b/src/vm/arm/exceparm.cpp
new file mode 100644
index 0000000000..6852adcc33
--- /dev/null
+++ b/src/vm/arm/exceparm.cpp
@@ -0,0 +1,144 @@
+// 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.
+//
+// File: ExcepArm.cpp
+
+#include "common.h"
+#include "asmconstants.h"
+#include "virtualcallstub.h"
+
+PTR_CONTEXT GetCONTEXTFromRedirectedStubStackFrame(T_DISPATCHER_CONTEXT * pDispatcherContext)
+{
+    LIMITED_METHOD_DAC_CONTRACT;
+
+    UINT_PTR stackSlot = pDispatcherContext->EstablisherFrame + REDIRECTSTUB_SP_OFFSET_CONTEXT;
+    PTR_PTR_CONTEXT ppContext = dac_cast<PTR_PTR_CONTEXT>((TADDR)stackSlot);
+    return *ppContext;
+}
+
+PTR_CONTEXT GetCONTEXTFromRedirectedStubStackFrame(T_CONTEXT * pContext)
+{
+    LIMITED_METHOD_DAC_CONTRACT;
+
+    UINT_PTR stackSlot = pContext->Sp + REDIRECTSTUB_SP_OFFSET_CONTEXT;
+    PTR_PTR_CONTEXT ppContext = dac_cast<PTR_PTR_CONTEXT>((TADDR)stackSlot);
+    return *ppContext;
+}
+
+#if !defined(DACCESS_COMPILE)
+
+// The next two functions help retrieve data kept relative to FaultingExceptionFrame that is setup
+// for handling async exceptions (e.g. AV, NullRef, ThreadAbort, etc).
+// 
+// FEF (and related data) is available relative to R4 - the thing to be kept in mind is that the 
+// DispatcherContext->ContextRecord:
+// 
+// 1) represents the caller context in the first pass.
+// 2) represents the current context in the second pass.
+// 
+// Since R4 is a non-volatile register, this works for us since we setup the value of R4
+// in the redirection helpers (e.g. NakedThrowHelper or RedirectForThreadAbort) but do not
+// change it in their respective callee functions (e.g. NakedThrowHelper2 or RedirectForThreadAbort2)
+// that have the personality routines associated with them (which perform the collided unwind and also
+// invoke the two functions below).
+// 
+// Thus, when our personality routine gets called in either passes, DC->ContextRecord->R4 will 
+// have the same value.
+
+// Returns the pointer to the FEF
+FaultingExceptionFrame *GetFrameFromRedirectedStubStackFrame (T_DISPATCHER_CONTEXT *pDispatcherContext)
+{
+    LIMITED_METHOD_CONTRACT;
+
+    return (FaultingExceptionFrame*)((TADDR)pDispatcherContext->ContextRecord->R4);
+}
+
+//Return TRUE if pContext->Pc is in VirtualStub
+BOOL IsIPinVirtualStub(PCODE f_IP)
+{
+    LIMITED_METHOD_CONTRACT;
+
+    Thread * pThread = GetThread();
+
+    // We may not have a managed thread object. Example is an AV on the helper thread.
+    // (perhaps during StubManager::IsStub)
+    if (pThread == NULL)
+    {
+        return FALSE;
+    }
+
+    VirtualCallStubManager::StubKind sk;
+    VirtualCallStubManager::FindStubManager(f_IP, &sk);
+
+    if (sk == VirtualCallStubManager::SK_DISPATCH)
+    {
+        return TRUE;
+    }
+    else if (sk == VirtualCallStubManager::SK_RESOLVE)
+    {
+        return TRUE;
+    }
+
+    else {
+        return FALSE;
+    }
+}
+
+
+// Returns TRUE if caller should resume execution.
+BOOL
+AdjustContextForVirtualStub(
+        EXCEPTION_RECORD *pExceptionRecord,
+        CONTEXT *pContext)
+{
+    LIMITED_METHOD_CONTRACT;
+
+    Thread * pThread = GetThread();
+
+    // We may not have a managed thread object. Example is an AV on the helper thread.
+    // (perhaps during StubManager::IsStub)
+    if (pThread == NULL)
+    {
+        return FALSE;
+    }
+
+    PCODE f_IP = GetIP(pContext);
+    TADDR pInstr = PCODEToPINSTR(f_IP);
+
+    VirtualCallStubManager::StubKind sk;
+    VirtualCallStubManager::FindStubManager(f_IP, &sk);
+
+    if (sk == VirtualCallStubManager::SK_DISPATCH)
+    {
+        if (*PTR_WORD(pInstr) != DISPATCH_STUB_FIRST_WORD)
+        {
+            _ASSERTE(!"AV in DispatchStub at unknown instruction");
+            return FALSE;
+        }
+    }
+    else
+    if (sk == VirtualCallStubManager::SK_RESOLVE)
+    {
+        if (*PTR_WORD(pInstr) != RESOLVE_STUB_FIRST_WORD)
+        {
+            _ASSERTE(!"AV in ResolveStub at unknown instruction");
+            return FALSE;
+        }
+    }
+    else
+    {
+        return FALSE;
+    }
+
+    PCODE callsite = GetAdjustedCallAddress(GetLR(pContext)); 
+
+    // Lr must already have been saved before calling so it should not be necessary to restore Lr
+
+    pExceptionRecord->ExceptionAddress = (PVOID)callsite;
+    SetIP(pContext, callsite);
+
+    return TRUE;
+}
+#endif // !DACCESS_COMPILE
+