Re: objtool warning "uses BP as a scratch register" with clang-9

From: Ilie Halip
Date: Tue Aug 27 2019 - 11:00:12 EST

> > $ clang-9 -c crc32.i -O2 ; objtool check crc32.o
> > crc32.o: warning: objtool: fn1 uses BP as a scratch register

Yes, I see it too.

> Do you still see this warning with -fno-omit-frame-pointer (assuming
> clang has that option)?

Using this makes the warning go away. Running objtool with --no-fp
also gets rid of it.