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1 | // Copyright 2015 The Rust Project Developers. See the COPYRIGHT |
2 | // file at the top-level directory of this distribution and at | |
3 | // http://rust-lang.org/COPYRIGHT. | |
4 | // | |
5 | // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or | |
6 | // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license | |
7 | // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your | |
8 | // option. This file may not be copied, modified, or distributed | |
9 | // except according to those terms. | |
10 | ||
11 | // General test of maybe_uninits state computed by MIR dataflow. | |
12 | ||
476ff2be | 13 | #![feature(core_intrinsics, rustc_attrs)] |
3157f602 XL |
14 | |
15 | use std::intrinsics::rustc_peek; | |
16 | use std::mem::{drop, replace}; | |
17 | ||
18 | struct S(i32); | |
19 | ||
20 | #[rustc_mir_borrowck] | |
21 | #[rustc_mir(rustc_peek_maybe_uninit,stop_after_dataflow)] | |
22 | fn foo(test: bool, x: &mut S, y: S, mut z: S) -> S { | |
23 | let ret; | |
24 | // `ret` starts off uninitialized | |
25 | unsafe { rustc_peek(&ret); } | |
26 | ||
27 | // All function formal parameters start off initialized. | |
28 | ||
29 | unsafe { rustc_peek(&x) }; //~ ERROR rustc_peek: bit not set | |
30 | unsafe { rustc_peek(&y) }; //~ ERROR rustc_peek: bit not set | |
31 | unsafe { rustc_peek(&z) }; //~ ERROR rustc_peek: bit not set | |
32 | ||
33 | ret = if test { | |
34 | ::std::mem::replace(x, y) | |
35 | } else { | |
36 | z = y; | |
37 | z | |
38 | }; | |
39 | ||
40 | // `z` may be uninitialized here. | |
41 | unsafe { rustc_peek(&z); } | |
42 | ||
43 | // `y` is definitely uninitialized here. | |
44 | unsafe { rustc_peek(&y); } | |
45 | ||
46 | // `x` is still (definitely) initialized (replace above is a reborrow). | |
47 | unsafe { rustc_peek(&x); } //~ ERROR rustc_peek: bit not set | |
48 | ||
49 | ::std::mem::drop(x); | |
50 | ||
51 | // `x` is *definitely* uninitialized here | |
52 | unsafe { rustc_peek(&x); } | |
53 | ||
54 | // `ret` is now definitely initialized (via `if` above). | |
55 | unsafe { rustc_peek(&ret); } //~ ERROR rustc_peek: bit not set | |
56 | ||
57 | ret | |
58 | } | |
59 | fn main() { | |
60 | foo(true, &mut S(13), S(14), S(15)); | |
61 | foo(false, &mut S(13), S(14), S(15)); | |
62 | } |