private static void SetupEHState(DarksVMContext ctx, object ex)
{
EHState ehState;
if (ctx.EHStates.Count != 0)
{
ehState = ctx.EHStates[ctx.EHStates.Count - 1];
if (ehState.CurrentFrame != null)
{
if (ehState.CurrentProcess == EHState.EHProcess.Searching)
{
ctx.Registers[DarksVMConstants.REG_R1].U1 = 0;
}
else if (ehState.CurrentProcess == EHState.EHProcess.Unwinding)
{
ehState.ExceptionObj = ex;
}
return;
}
}
ehState = new EHState
{
OldBP = ctx.Registers[DarksVMConstants.REG_BP],
OldSP = ctx.Registers[DarksVMConstants.REG_SP],
ExceptionObj = ex,
CurrentProcess = EHState.EHProcess.Searching,
CurrentFrame = null,
HandlerFrame = null
};
ctx.EHStates.Add(ehState);
}
static void SetupEHState(VMContext ctx, object ex)
{
EHState ehState;
if (ctx.EHStates.Count != 0)
{
ehState = ctx.EHStates[ctx.EHStates.Count - 1];
if (ehState.CurrentFrame != null)
{
if (ehState.CurrentProcess == EHState.EHProcess.Searching)
{
// Return from filter => throw exception, default to 0 by Partition III 3.34
ctx.Registers[Constants.REG_R1].U1 = 0;
}
else if (ehState.CurrentProcess == EHState.EHProcess.Unwinding)
{
// Return from finally => throw exception, replace current exception
// https://stackoverflow.com/questions/2911215/what-happens-if-a-finally-block-throws-an-exception
ehState.ExceptionObj = ex;
}
return;
}
}
ehState = new EHState {
OldBP = ctx.Registers[Constants.REG_BP],
OldSP = ctx.Registers[Constants.REG_SP],
ExceptionObj = ex,
CurrentProcess = EHState.EHProcess.Searching,
CurrentFrame = null,
HandlerFrame = null
};
ctx.EHStates.Add(ehState);
}
private static void HandleEH(DarksVMContext ctx, ref ExecutionState state)
{
EHState ehState = ctx.EHStates[ctx.EHStates.Count - 1];
switch (ehState.CurrentProcess)
{
case EHState.EHProcess.Searching:
{
if (ehState.CurrentFrame != null)
{
// Return from filter
bool filterResult = ctx.Registers[DarksVMConstants.REG_R1].U1 != 0;
if (filterResult)
{
ehState.CurrentProcess = EHState.EHProcess.Unwinding;
ehState.HandlerFrame = ehState.CurrentFrame;
ehState.CurrentFrame = ctx.EHStack.Count;
state = ExecutionState.Next;
goto case EHState.EHProcess.Unwinding;
}
ehState.CurrentFrame--;
}
else
{
ehState.CurrentFrame = ctx.EHStack.Count - 1;
}
Type exType = ehState.ExceptionObj.GetType();
for (; ehState.CurrentFrame >= 0 && ehState.HandlerFrame == null; ehState.CurrentFrame--)
{
EHFrame frame = ctx.EHStack[ehState.CurrentFrame.Value];
if (frame.EHType == DarksVMConstants.EH_FILTER)
{
// Run filter
uint sp = ehState.OldSP.U4;
ctx.Stack.SetTopPosition(++sp);
ctx.Stack[sp] = new DarksVMSlot {
O = ehState.ExceptionObj
};
ctx.Registers[DarksVMConstants.REG_K1].U1 = 0;
ctx.Registers[DarksVMConstants.REG_SP].U4 = sp;
ctx.Registers[DarksVMConstants.REG_BP] = frame.BP;
ctx.Registers[DarksVMConstants.REG_IP].U8 = frame.FilterAddr;
break;
}
if (frame.EHType == DarksVMConstants.EH_CATCH)
{
if (frame.CatchType.IsAssignableFrom(exType))
{
ehState.CurrentProcess = EHState.EHProcess.Unwinding;
ehState.HandlerFrame = ehState.CurrentFrame;
ehState.CurrentFrame = ctx.EHStack.Count;
goto case EHState.EHProcess.Unwinding;
}
}
}
if (ehState.CurrentFrame == -1 && ehState.HandlerFrame == null)
{
ctx.EHStates.RemoveAt(ctx.EHStates.Count - 1);
state = ExecutionState.Rethrow;
if (ctx.EHStates.Count == 0)
{
HandleRethrow(ctx, ehState.ExceptionObj);
}
}
else
{
state = ExecutionState.Next;
}
break;
}
case EHState.EHProcess.Unwinding:
{
ehState.CurrentFrame--;
int i;
for (i = ehState.CurrentFrame.Value; i > ehState.HandlerFrame.Value; i--)
{
EHFrame frame = ctx.EHStack[i];
ctx.EHStack.RemoveAt(i);
if (frame.EHType == DarksVMConstants.EH_FAULT || frame.EHType == DarksVMConstants.EH_FINALLY)
{
// Run finally
SetupFinallyFrame(ctx, frame);
break;
}
}
ehState.CurrentFrame = i;
if (ehState.CurrentFrame == ehState.HandlerFrame)
{
EHFrame frame = ctx.EHStack[ehState.HandlerFrame.Value];
ctx.EHStack.RemoveAt(ehState.HandlerFrame.Value);
// Run handler
frame.SP.U4++;
ctx.Stack.SetTopPosition(frame.SP.U4);
ctx.Stack[frame.SP.U4] = new DarksVMSlot {
O = ehState.ExceptionObj
};
ctx.Registers[DarksVMConstants.REG_K1].U1 = 0;
ctx.Registers[DarksVMConstants.REG_SP] = frame.SP;
ctx.Registers[DarksVMConstants.REG_BP] = frame.BP;
ctx.Registers[DarksVMConstants.REG_IP].U8 = frame.HandlerAddr;
ctx.EHStates.RemoveAt(ctx.EHStates.Count - 1);
}
state = ExecutionState.Next;
break;
}
default:
throw new ExecutionEngineException();
}
}
