Instructing decompiler on function register clobbers?

[sad-dev]

I find that many functions e.g. constructors tend to preserve some registers, which the compiler gleefully takes advantage of. The typical outcome is variables like extraout_ECX in the decompiler output of the caller of such a function. Inlining (when applicable, which isn't always the case) leads to bloat in the size of the decompiler output

I have a very hacky workaround involving adding bogus calling conventions (an example for x86 windows at sad-dev@d6f6bbb ), but surely this can't be the only way? I also do not see a way to specify inputs as IN/OUT/INOUT, even by hacking the cspec, so any suggestions are most welcome

My guess is that any sane solution would involve extending the schema to store function prototype related overrides e.g. preserved registers, OUT directives, etc. I can probably implement this for a POC pull request, but don't know enough about the decompiler to say how much would need to be changed to take advantage of this new information.