alt Hacker News> If even 1 instruction or bit is off, that's a fail.
Does this assume having access to the exact version of the compiler use, or can it be done with a different compiler in practice?
And do you care about things like binary layout, or just instruction match? (Does that ever matter in practice?)
Yes, exact version of the original compiler is required.
Generally bit-for-bit equivalence to the original executable is expected. However I think for some cases where the original executable included debug info (eg. PS2 ELFs) then the unused-at-runtime sections need not match.