diff options
Diffstat (limited to 'src/cmd/5g/cgen.c')
| -rw-r--r-- | src/cmd/5g/cgen.c | 67 |
1 files changed, 40 insertions, 27 deletions
diff --git a/src/cmd/5g/cgen.c b/src/cmd/5g/cgen.c index 9e35f9566..1620f410a 100644 --- a/src/cmd/5g/cgen.c +++ b/src/cmd/5g/cgen.c @@ -679,6 +679,21 @@ agen(Node *n, Node *res) case ODOT: agen(nl, res); + // explicit check for nil if struct is large enough + // that we might derive too big a pointer. If the left node + // was ODOT we have already done the nil check. + if(nl->op != ODOT) + if(nl->type->width >= unmappedzero) { + regalloc(&n1, types[tptr], N); + gmove(res, &n1); + regalloc(&n2, types[TUINT8], &n1); + n1.op = OINDREG; + n1.type = types[TUINT8]; + n1.xoffset = 0; + gmove(&n1, &n2); + regfree(&n1); + regfree(&n2); + } if(n->xoffset != 0) { nodconst(&n1, types[TINT32], n->xoffset); regalloc(&n2, n1.type, N); @@ -694,20 +709,20 @@ agen(Node *n, Node *res) case ODOTPTR: cgen(nl, res); + // explicit check for nil if struct is large enough + // that we might derive too big a pointer. + if(nl->type->type->width >= unmappedzero) { + regalloc(&n1, types[tptr], N); + gmove(res, &n1); + regalloc(&n2, types[TUINT8], &n1); + n1.op = OINDREG; + n1.type = types[TUINT8]; + n1.xoffset = 0; + gmove(&n1, &n2); + regfree(&n1); + regfree(&n2); + } if(n->xoffset != 0) { - // explicit check for nil if struct is large enough - // that we might derive too big a pointer. - if(nl->type->type->width >= unmappedzero) { - regalloc(&n1, types[tptr], N); - gmove(res, &n1); - regalloc(&n2, types[TUINT8], &n1); - n1.op = OINDREG; - n1.type = types[TUINT8]; - n1.xoffset = 0; - gmove(&n1, &n2); - regfree(&n1); - regfree(&n2); - } nodconst(&n1, types[TINT32], n->xoffset); regalloc(&n2, n1.type, N); regalloc(&n3, types[tptr], N); @@ -777,20 +792,18 @@ igen(Node *n, Node *a, Node *res) regalloc(a, types[tptr], res); cgen(n->left, a); } - if(n->xoffset != 0) { - // explicit check for nil if struct is large enough - // that we might derive too big a pointer. - if(n->left->type->type->width >= unmappedzero) { - regalloc(&n1, types[tptr], N); - gmove(a, &n1); - regalloc(&n2, types[TUINT8], &n1); - n1.op = OINDREG; - n1.type = types[TUINT8]; - n1.xoffset = 0; - gmove(&n1, &n2); - regfree(&n1); - regfree(&n2); - } + // explicit check for nil if struct is large enough + // that we might derive too big a pointer. + if(n->left->type->type->width >= unmappedzero) { + regalloc(&n1, types[tptr], N); + gmove(a, &n1); + regalloc(&n2, types[TUINT8], &n1); + n1.op = OINDREG; + n1.type = types[TUINT8]; + n1.xoffset = 0; + gmove(&n1, &n2); + regfree(&n1); + regfree(&n2); } a->op = OINDREG; a->xoffset = n->xoffset; |