Date: Sun, 22 Oct 1995 16:27:01 +1000 From: Bruce Evans <bde@zeta.org.au> To: pst@shockwave.com, swallace@ece.uci.edu Cc: CVS-commiters@freefall.freebsd.org, bde@freefall.freebsd.org, cvs-sys@freefall.freebsd.org, hackers@freebsd.org Subject: Re: SYSCALL IDEAS [Was: cvs commit: src/sys/kern sysv_msg.c sysv_sem.c sysv_shm.c] Message-ID: <199510220627.QAA22831@godzilla.zeta.org.au>
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>While I realize this is a bit against the philosophy that some of the
>team members hold, which is that we should not rely on gcc-type
>functionality, I'd actually prefer to see things like SCARG and
>prototype-glue done as static inlines where appropriate.
4.4lite already uses `static inline' extensively for vnode ops. I'd
still like everything to work on non-gcc compilers. When `static' is
defined to nothing, `static inline' should at most waste a lot of space
and a little time...
>The reason
>being is that with a static inline, as you can enforce type checking
>with:
> static inline struct rntype *
> rt2rn (struct rttype *rt)
> {
> return (rntype *) rt;
> }
>as opposed to
> #define RT2RN(x) ((rntype *) (x))
..or waste a lot of time if a lot of little functions like that aren't
inlined :-).
I would call that defeating type checking. You'll only get a warning if
x has an incompatible type, not for the bogus cast. For syscall args I
want something more like:
static inline struct rntype *
rt2rn (struct rttype *rt)
{
/*
* Machine generated code to do the conversion.
* Do not edit.
*/
#ifdef rt2rn_type_pun_works
return (rntype *) rt;
#else
struct rntype rn = somealloc(sizeof *rn);
rn->rn_foo = rt->rt_foo;
rn->rn_bar = rt->rt_bar;
return rn;
#endif
}
>* every time you use the register tag, your're strongly encouraging
> gcc to reserve a register for use by that variable. gcc, unlike pcc,
> already understands when it should and shouldn't use registers and
> can do this far better than we can, so it's a bad idea to hamstring
I don't think use of `register' makes any difference for gcc for variables
that can go in registers (i.e., auto variables whose address isn't taken).
Bruce
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