Hojun-Cho
ab0976571b
Mirror of 548547a in the wwstage cgen.
cgexpr learns N_SLICE: `base[lo:hi]` leaves (AX=ptr, BX=len, CX=cap)
so callers (return, arg push, reassignment, let init for fn-returning-
slice / slice-ident) share one triple ABI. Without this, the existing
let-init that just forwards (AX,BX,CX) to the slot was silently storing
junk on a base[lo:hi] rhs.
cgassign gains a slice branch parallel to str: for a local slice ident
lhs, store all three halves to off+0/+8/+16; for a slice global, stash
CX into DI before LEAQ-ing the symbol address into CX (CX is both the
incoming cap and the LEAQ scratch), then store AX/BX/DI at +0/+8/+16.
N_IDENT slice-local triple load was already in place from the earlier
selfhost port; only the cgexpr and cgassign halves needed adding.
Byte-identical to C w6c on the corpus — make test 26/26, 994_w6c_ww
passes on 10 inputs, 990_selfhost + 995_self_rebuild reach fixed point.