On Sun, Jan 14, 2018 at 12:03:42AM +0200, Karim Eshapa wrote: > Use pointers to structure as arguments to function instead of coping > structures and less stack size. Also transfer TNUM(_v, _m) to > tnum.h file to be used in differnet files for creating anonymous structures > statically. > > Signed-off-by: Karim Eshapa <karim.esh...@gmail.com> ... > +/* Statically tnum constant */ > +#define TNUM(_v, _m) (struct tnum){.value = _v, .mask = _m} > /* Represent a known constant as a tnum. */ > struct tnum tnum_const(u64 value); > /* A completely unknown value */ > @@ -26,7 +28,7 @@ struct tnum tnum_lshift(struct tnum a, u8 shift); > /* Shift a tnum right (by a fixed shift) */ > struct tnum tnum_rshift(struct tnum a, u8 shift); > /* Add two tnums, return @a + @b */ > -struct tnum tnum_add(struct tnum a, struct tnum b); > +void tnum_add(struct tnum *res, struct tnum *a, struct tnum *b); ... > - reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off)); > + tnum_add(®_off, ®->var_off, &TNUM(ip_align + reg->off + off, 0)); > if (!tnum_is_aligned(reg_off, size)) { > char tn_buf[48]; > > @@ -1023,8 +1023,7 @@ static int check_generic_ptr_alignment(struct > bpf_verifier_env *env, > /* Byte size accesses are always allowed. */ > if (!strict || size == 1) > return 0; > - > - reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off)); > + tnum_add(®_off, ®->var_off, &TNUM(reg->off + off, 0)); ... > - dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off); > + tnum_add(&dst_reg->var_off, &ptr_reg->var_off, > + &off_reg->var_off);
I think that looks much worse and error prone. Is it gnu or intel style of argumnets ? where is src or dest ? Can the same pointer be used as src and as dst ? etc, etc I don't think it saves stack either. I'd rather leave things as-is.