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Avoid superfluous take/drop for temp values passes as arguments

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This commit is contained in:
Marijn Haverbeke 2011-07-08 11:02:26 +02:00
parent b41fd61045
commit faec0d7799
1 changed files with 16 additions and 8 deletions
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24
src/comp/middle/trans.rs
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@ -5694,12 +5694,23 @@ fn trans_arg_expr(&@block_ctxt cx, &ty::arg arg, TypeRef lldestty0,
auto dst = alloc_ty(bcx, e_ty);
val = dst.val;
bcx = move_val_if_temp(dst.bcx, INIT, val, lv, e_ty).bcx;
} else {
if (lv.is_mem) { val = load_if_immediate(bcx, val, e_ty); }
// FIXME for non-is-mem lvals, we should be able to just drop the
// cleanup. However, this currently leads to a memory-corrupting
// stage2/rustc . Find out why.
} else if (lv.is_mem) {
val = load_if_immediate(bcx, val, e_ty);
bcx = copy_ty(bcx, val, e_ty).bcx;
} else {
// Eliding take/drop for appending of external vectors currently
// corrupts memory. I can't figure out why, and external vectors
// are on the way out anyway, so this simply turns off the
// optimization for that case.
auto is_ext_vec_plus = alt (e.node) {
case (ast::expr_binary(_, _, _)) {
ty::type_is_sequence(ccx.tcx, e_ty) &&
!ty::sequence_is_interior(ccx.tcx, e_ty)
}
case (_) { false }
};
if (is_ext_vec_plus) { bcx = copy_ty(bcx, val, e_ty).bcx; }
else { revoke_clean(bcx, val); }
}
} else if (type_is_immediate(ccx, e_ty) && !lv.is_mem) {
val = do_spill(bcx, val);
@ -6368,11 +6379,8 @@ fn with_out_method(fn(&out_method) -> result work, @block_ctxt cx,
auto reg_val = load_if_immediate(cx, target, t);
ret drop_ty(cx, reg_val, t);
}
auto cleanup = bind drop_hoisted_ty(_, res_alloca.val, tp);
find_scope_cx(cx).cleanups += ~[clean_temp(res_alloca.val, cleanup)];
auto done = work(save_in(res_alloca.val));
auto loaded = load_if_immediate(done.bcx, res_alloca.val, tp);
revoke_clean(cx, res_alloca.val);
add_clean_temp(cx, loaded, tp);
ret rslt(done.bcx, loaded);;
}