Find misuses of global variables/functions, casted to integers

[pgoodman]

We should be able to identify things like this:

  store i64 and (i64 add (i64 ptrtoint (%seg_400ae0__rodata_type* @seg_400ae0__rodata to i64),
                          i64 32),
                 i64 4294967295),
        i64* %7

And remove the and (..., i64 4294967295), which masks the integer address of seg_400ae0__rodata to be a 32-bit value.

[pgoodman]

So they might not exactly be misuses, but I think we could technically "fix things up." This would be a good command-line toggle-able. For example, it should be permissible in the following example, because the write to edi in both cases is really a write to rdi (as is shown in the bitcode).

And the bitcode looks like:

I think the easiest way to approach this is to iterate over global variables, look at their uses, and see if they show up in a ptrtoint that is then anded to become a 32-bit value, or truncd and zextd.

A motivation for doing this would be to take a static binary and convert it into a PIE.