[PATCH v3 1/4] dbghelp: Avoid using inline assembly in do_x86cpuid().

[Gabriel Ivăncescu]

On Mon, Nov 26, 2018 at 9:00 PM Zebediah Figura <z.figura12 at gmail.com> wrote:
>
> "Easier to maintain" may be subjective; I personally find the constraint
> mnemonics harder to read. In any case I doubt that performance should be
> a concern here.
>
> The first such patch I sent was 0c216b8ca, it was motivated by clang
> generating references to %esp despite the use of stack instructions (and
> despite -fno-omit-frame-pointer). Alexandre prescribed avoiding inline
> assembly for all but the most simple functions, IIRC because constraints
> are generally trickier to get right.
>

I see, thanks for the explanation. By easier to maintain, I was
thinking more along the lines of: less code to sift through, easier to
change (no hardcoded offsets), not having to take into account calling
conventions, etc.

But I'm probably biased here due to my experience with inline assembly
and a little bit of GCC's internals, so asm operands and constraints
are sort of second nature to me and I find them very straightforward
(I just think of the asm statements as a black box, with inputs and
outputs). But that's most likely not the case for most people, so I
didn't realize it, and I thought there were other reasons.  (well,
except for x87 reg constraints, those are hard to understand by
anyone)