diff options
Diffstat (limited to 'src/cmd/gc/gen.c')
| -rw-r--r-- | src/cmd/gc/gen.c | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/src/cmd/gc/gen.c b/src/cmd/gc/gen.c index 5012e4a52d..9806600277 100644 --- a/src/cmd/gc/gen.c +++ b/src/cmd/gc/gen.c @@ -734,6 +734,66 @@ ret: ; } + +/* + * generate: + * res = s[lo, hi]; + * n->left is s + * n->list is (cap(s)-lo(TUINT32), hi-lo(TUINT32)[, lo*width(TUINTPTR)]) + * caller (cgen) guarantees res is an addable ONAME. + * + */ +void +cgen_slice(Node *n, Node *res) +{ + Node src, dst, *cap, *len, *offs, *add; + +// print("cgen_slice: %N = %+N\n", res, n); + + cap = n->list->n; + len = n->list->next->n; + offs = N; + if(n->list->next->next) + offs = n->list->next->next->n; + + // dst.len = hi [ - lo ] + dst = *res; + dst.xoffset += Array_nel; + dst.type = types[TUINT32]; + cgen(len, &dst); + + if(n->op != OSLICESTR) { + // dst.cap = cap [ - lo ] + dst = *res; + dst.xoffset += Array_cap; + dst.type = types[TUINT32]; + cgen(cap, &dst); + } + + // dst.array = src.array [ + lo *width ] + dst = *res; + dst.xoffset += Array_array; + dst.type = types[TUINTPTR]; + + if(n->op == OSLICEARR) { + if(!isptr[n->left->type->etype]) + fatal("slicearr is supposed to work on pointer: %+N\n", n); + checkref(n->left); + } + + src = *n->left; + src.xoffset += Array_array; + src.type = types[TUINTPTR]; + + if(offs == N) { + cgen(&src, &dst); + } else { + add = nod(OADD, &src, offs); + typecheck(&add, Erv); + cgen(add, &dst); + } +} + /* * gather series of offsets * >=0 is direct addressed field |