Hello All,

I am trying to add two methods in de4dot.blocks.cflow.InstructionEmulator.

private void Emulate_Stelem_I4(Instruction instr)
{
    Value value = this.valueStack.Pop();
    bool flag = value.IsInt32();
    if (flag)
    {
        Int32Value int32Value = (Int32Value)this.valueStack.Pop();
        List<Value> list = this.valueStack.Pop();
        list[int32Value.Value] = (Int32Value)value;
    }
    else
    {
        this.valueStack.Pop();
        this.valueStack.Pop();
    }

 

private void Emulate_Ldelem_I4(Instruction instr)
{
    Int32Value int32Value = (Int32Value)this.valueStack.Pop();
    List<Value> list = this.valueStack.Pop();
    Value value = list[int32Value.Value];
    bool flag = value.IsInt32();
    if (flag)
    {
        this.valueStack.Push(list[int32Value.Value]);
    }
    else
    {
        this.valueStack.Push(Int32Value.CreateUnknown());
    }
}

Ref: https://github.com/mobile46/de4dot/blob/master/de4dot.blocks/cflow/InstructionEmulator.cs

I am getting the following error

Unhandled Exception: System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index
   at System.ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument argument, ExceptionResource resource)
   at System.Collections.Generic.List`1.get_Item(Int32 index)
   at de4dot.blocks.cflow.InstructionEmulator.Emulate_Ldelem_I4(Instruction instr)
   at de4dot.blocks.cflow.InstructionEmulator.Emulate(Instruction instr)

What am I doing wrong? What is the correct way to do it?

 

Thank you

Edited March 27, 20241 yr by extonoxt

the issue is that

>ThrowArgumentOutOfRangeException

is unhappy that for example you have a list  with 3 elements [1,2,3]

but for some reason you want to access a element with index 5

as you have just 3 elements in your list you are beating by this kind of exception

 

Value value = list[int32Value.Value];      <<  here is hits the exception

3 hours ago, jackyjask said:

Value value = list[int32Value.Value];      <<  here is hits the exception

Thank you jackyjask,

I solved it by using GetValue of the same class