我有一些代码来交换COM vtable中的一个函数指针与汇编代码的NO-OP位。* 它在twinBASIC* 中工作，这是一个独立的JavaScript环境，所以我知道我非常接近，但是在Excel中它崩溃了。
这是minrepro，工程在tB和理论上不是在Excel中.

Class DummyThing
    Sub DoNothing()
    End Sub
End Class

Module VBA
    Private Const MEM_COMMIT As Long = &H1000
    Private Const MEM_RESERVE As Long = &H2000
    Private Const PAGE_EXECUTE_READWRITE  As Long = &H40

    Declare PtrSafe Function VirtualAlloc Lib "kernel32" ( _
            ByVal lpAddress As LongPtr, _
            ByVal dwSize As Long, _
            ByVal flAllocationType As Long, _
            ByVal flProtect As Long) As LongPtr

    Sub Main()
        Dim code(1 To 4) As Byte
        code(1) = CByte(&h48)    
        code(2) = CByte(&h31)
        code(3) = CByte(&hC0) 'xor rax, rax to clear it - this is like setting the hresult to 0
        code(4) = CByte(&hC3) 'ret

        Dim buffer As LongPtr
        buffer = VirtualAlloc(0&, UBound(code) - LBound(code) + 1, MEM_COMMIT Or MEM_RESERVE, PAGE_EXECUTE_READWRITE)

        If buffer = 0 Then
            Debug.Print "VirtualAlloc() failed (Err:" ; Err.LastDllError ; ")."
            Exit Sub
        End If

        CopyMemory ByVal buffer, code(1), UBound(code) - LBound(code) + 1

        Dim base As DummyThing
        Set base = New DummyThing

        Dim vtable As LongPtr
        vtable = MemLongPtr(ObjPtr(base))

        MemLongPtr(vtable + PTR_SIZE * 7) = buffer

        base.DoNothing 'Excel VBA crashes here, tB prints the message below
        Debug.Print vbNewLine ; "Done!"
    End Sub

End Module

内存api来自这里https://github.com/cristianbuse/VBA-MemoryTools/blob/master/src/LibMemory.bas
它是一个超级简单的64位汇编代码，通过交换Sub DoNothing()的vtable并将其替换为指向某些可执行操作码的指针来运行。汇编代码只不过是

48 31 C0          xor    rax, rax                ; Set return value to 0
C3                ret                            ; Return

可能是什么原因导致崩溃--可能是因为MySQL检查了vtable的完整性，并且它指向了预期地址范围内的内存？但我以前在重载vtables时从未遇到过这个问题。