64 lines
1.8 KiB
Rust
64 lines
1.8 KiB
Rust
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// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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// General test of maybe_uninits state computed by MIR dataflow.
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#![feature(rustc_attrs)]
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#![feature(stmt_expr_attributes)]
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use std::intrinsics::rustc_peek;
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use std::mem::{drop, replace};
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struct S(i32);
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#[rustc_mir_borrowck]
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#[rustc_mir(rustc_peek_maybe_uninit,stop_after_dataflow)]
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fn foo(test: bool, x: &mut S, y: S, mut z: S) -> S {
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let ret;
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// `ret` starts off uninitialized
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unsafe { rustc_peek(&ret); }
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// All function formal parameters start off initialized.
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unsafe { rustc_peek(&x) }; //~ ERROR rustc_peek: bit not set
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unsafe { rustc_peek(&y) }; //~ ERROR rustc_peek: bit not set
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unsafe { rustc_peek(&z) }; //~ ERROR rustc_peek: bit not set
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ret = if test {
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::std::mem::replace(x, y)
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} else {
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z = y;
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z
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};
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// `z` may be uninitialized here.
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unsafe { rustc_peek(&z); }
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// `y` is definitely uninitialized here.
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unsafe { rustc_peek(&y); }
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// `x` is still (definitely) initialized (replace above is a reborrow).
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unsafe { rustc_peek(&x); } //~ ERROR rustc_peek: bit not set
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::std::mem::drop(x);
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// `x` is *definitely* uninitialized here
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unsafe { rustc_peek(&x); }
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// `ret` is now definitely initialized (via `if` above).
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unsafe { rustc_peek(&ret); } //~ ERROR rustc_peek: bit not set
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ret
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}
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fn main() {
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foo(true, &mut S(13), S(14), S(15));
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foo(false, &mut S(13), S(14), S(15));
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}
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