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Properly guard resource values against double-drop

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Ths involved adding an extra field to their representation, so that there is
something to check for zero.
This commit is contained in:
Marijn Haverbeke 2011-06-28 16:14:01 +02:00
parent ecc080ed0b
commit be748fc215
1 changed files with 51 additions and 18 deletions
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69
src/comp/middle/trans.rs
View file

@ -884,7 +884,7 @@ fn type_of_inner(&@crate_ctxt cx, &span sp, &ty::t t) -> TypeRef {
llty = abs_pair;
}
case (ty::ty_res(_, ?sub)) {
ret type_of_inner(cx, sp, sub);
ret T_struct([T_i32(), type_of_inner(cx, sp, sub)]);
}
case (ty::ty_var(_)) {
cx.tcx.sess.span_fatal(sp, "trans::type_of called on ty_var");
@ -1227,7 +1227,10 @@ fn simplify_type(&@crate_ctxt ccx, &ty::t typ) -> ty::t {
ty::mk_imm_box(ccx.tcx,
ty::mk_nil(ccx.tcx))]);
}
case (ty::ty_res(_, ?sub)) { ret simplify_type(ccx, sub);}
case (ty::ty_res(_, ?sub)) {
ret ty::mk_imm_tup(ccx.tcx, [ty::mk_int(ccx.tcx),
simplify_type(ccx, sub)]);
}
case (_) { ret typ; }
}
}
@ -2068,7 +2071,6 @@ fn maybe_free_ivec_heap_part(&@block_ctxt cx, ValueRef v0, ty::t unit_ty) ->
fn make_drop_glue(&@block_ctxt cx, ValueRef v0, &ty::t t) {
// NB: v0 is an *alias* of type t here, not a direct value.
auto ccx = cx.fcx.lcx.ccx;
auto rs = alt (ty::struct(ccx.tcx, t)) {
case (ty::ty_str) { decr_refcnt_maybe_free(cx, v0, v0, t) }
@ -2094,16 +2096,15 @@ fn make_drop_glue(&@block_ctxt cx, ValueRef v0, &ty::t t) {
decr_refcnt_maybe_free(cx, box_cell, v0, t)
}
case (ty::ty_res(?did, ?inner)) {
auto dtor = alt (ccx.ast_map.get(did._1)) {
(alt (ccx.ast_map.get(did._1)) {
case (ast_map::node_item(?i)) {
alt (i.node) {
case (ast::item_res(?dtor, _, _, _)) { dtor }
case (ast::item_res(?dtor, _, _, _)) {
drop_res(cx, v0, inner, dtor)
}
}
}
};
cx.fcx.llargs.insert(dtor.decl.inputs.(0).id, v0);
auto rs = trans_block(cx, dtor.body, return);
drop_ty(rs.bcx, v0, inner)
})
}
case (ty::ty_fn(_, _, _, _, _)) {
auto box_cell =
@ -2120,6 +2121,30 @@ fn make_drop_glue(&@block_ctxt cx, ValueRef v0, &ty::t t) {
rs.bcx.build.RetVoid();
}
fn drop_res(@block_ctxt cx, ValueRef rs, ty::t inner_t, &ast::_fn dtor)
-> result {
auto ccx = cx.fcx.lcx.ccx;
auto tup_ty = ty::mk_imm_tup(ccx.tcx, [ty::mk_int(ccx.tcx), inner_t]);
auto drop_cx = new_sub_block_ctxt(cx, "drop res");
auto next_cx = new_sub_block_ctxt(cx, "next");
auto drop_flag = GEP_tup_like(cx, tup_ty, rs, [0, 0]);
cx = drop_flag.bcx;
auto null_test = cx.build.IsNull(cx.build.Load(drop_flag.val));
cx.build.CondBr(null_test, next_cx.llbb, drop_cx.llbb);
cx = drop_cx;
auto val = GEP_tup_like(cx, tup_ty, rs, [0, 1]);
cx = val.bcx;
cx.fcx.llargs.insert(dtor.decl.inputs.(0).id, val.val);
cx = trans_block(cx, dtor.body, return).bcx;
cx = drop_ty(cx, val.val, inner_t).bcx;
cx.build.Store(C_int(0), drop_flag.val);
cx.build.Br(next_cx.llbb);
ret rslt(next_cx, C_nil());
}
fn decr_refcnt_maybe_free(&@block_ctxt cx, ValueRef box_ptr_alias,
ValueRef full_alias, &ty::t t) -> result {
auto load_rc_cx = new_sub_block_ctxt(cx, "load rc");
@ -2573,8 +2598,12 @@ fn iter_structural_ty_full(&@block_ctxt cx, ValueRef av, ValueRef bv,
}
}
case (ty::ty_res(_, ?inner)) {
f(r.bcx, load_if_immediate(r.bcx, av, inner),
load_if_immediate(r.bcx, bv, inner), inner);
r = GEP_tup_like(r.bcx, t, av, [0, 1]);
auto llfld_a = r.val;
r = GEP_tup_like(r.bcx, t, bv, [0, 1]);
auto llfld_b = r.val;
f(r.bcx, load_if_immediate(r.bcx, llfld_a, inner),
load_if_immediate(r.bcx, llfld_b, inner), inner);
}
case (ty::ty_tag(?tid, ?tps)) {
auto variants = ty::tag_variants(cx.fcx.lcx.ccx.tcx, tid);
@ -7691,17 +7720,21 @@ fn trans_res(@local_ctxt cx, &span sp, &ast::_fn f, ast::node_id ctor_id,
&vec[ast::ty_param] ty_params) {
auto llctor_decl = cx.ccx.item_ids.get(ctor_id);
auto fcx = new_fn_ctxt(cx, sp, llctor_decl);
auto ret_ty = ty::ret_ty_of_fn(cx.ccx.tcx, ctor_id);
auto ret_t = ty::ret_ty_of_fn(cx.ccx.tcx, ctor_id);
create_llargs_for_fn_args(fcx, ast::proto_fn, none[ty_self_pair],
ret_ty, f.decl.inputs, ty_params);
ret_t, f.decl.inputs, ty_params);
auto bcx = new_top_block_ctxt(fcx);
auto lltop = bcx.llbb;
auto self_ty = ty::ret_ty_of_fn(cx.ccx.tcx, ctor_id);
auto llself_ty = type_of(cx.ccx, sp, self_ty);
auto arg_ty = arg_tys_of_fn(cx.ccx, ctor_id).(0).ty;
auto arg_t = arg_tys_of_fn(cx.ccx, ctor_id).(0).ty;
auto tup_t = ty::mk_imm_tup(cx.ccx.tcx, [ty::mk_int(cx.ccx.tcx), arg_t]);
auto arg = load_if_immediate
(bcx, fcx.llargs.get(f.decl.inputs.(0).id), arg_ty);
bcx = copy_val(bcx, INIT, fcx.llretptr, arg, arg_ty).bcx;
(bcx, fcx.llargs.get(f.decl.inputs.(0).id), arg_t);
auto dst = GEP_tup_like(bcx, tup_t, fcx.llretptr, [0, 1]);
bcx = dst.bcx;
bcx = copy_val(bcx, INIT, dst.val, arg, arg_t).bcx;
auto flag = GEP_tup_like(bcx, tup_t, fcx.llretptr, [0, 0]);
bcx = flag.bcx;
bcx.build.Store(C_int(1), flag.val);
bcx.build.RetVoid();
finish_fn(fcx, lltop);
}