Nibble Stew: How much effort would it take to convert OpenSSL's Perl source code generators to Python?

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2021-07-30 07:30:18

There is an ongoing discussion to write Meson build definitions to OpenSSL so it can be added to the WrapDB and built transparently as a subproject. One major issue is that OpenSSL generates a lot of assembly during build time with Perl. Having a Perl dependency would be bad, but shipping pregenerated source files would also be bad. Having "some pregenerated asm" that comes from "somewhere" would understandably be bad in a crypto library.

The obvious third option would be to convert the generator script from Perl to Python. This is not the first time this has been proposed and the counterargument has always been that said conversion would take an unreasonable amount of effort and could never be done. Since nobody has tried to do the conversion we don't really know whether that claim is accurate or not. I converted the x86_64 AES asm generator to see how much work it would actually take. The code is here.

The asm generator has two different levels of generators. First a Perl script generates asm in a specific format and after that a second Perl script converts it to a different asm type if needed (Nasm, At&T, Intel etc). The first script can be found here and the second one is here. In this test only the first script was converted.