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Auto merge of #52115 - Dylan-DPC:feature/nll-liveness-regions, r=nikomatsakis

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only compute liveness for variables whose types include regions

Closes #52034

r? @nikomatsakis
This commit is contained in:
bors 2018-07-21 21:01:17 +00:00
commit 874dec25ed
11 changed files with 304 additions and 359 deletions
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45
src/test/mir-opt/nll/liveness-call-subtlety.rs
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// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags:-Zborrowck=mir
fn can_panic() -> Box<usize> {
Box::new(44)
}
fn main() {
let mut x = Box::new(22);
x = can_panic();
}
// Check that:
// - `_1` is the variable corresponding to `x`
// and
// - `_1` is live when `can_panic` is called (because it may be dropped)
//
// END RUST SOURCE
// START rustc.main.nll.0.mir
// bb0: {
// | Live variables on entry to bb0[0]: []
// StorageLive(_1);
// | Live variables on entry to bb0[1]: []
// _1 = const <std::boxed::Box<T>>::new(const 22usize) -> [return: bb2, unwind: bb1];
// | Live variables on exit from bb0: [_1 (drop)]
// }
// END rustc.main.nll.0.mir
// START rustc.main.nll.0.mir
// bb2: {
// | Live variables on entry to bb2[0]: [_1 (drop)]
// StorageLive(_2);
// | Live variables on entry to bb2[1]: [_1 (drop)]
// _2 = const can_panic() -> [return: bb3, unwind: bb4];
// | Live variables on exit from bb2: [_1 (drop), _2]
// }
// END rustc.main.nll.0.mir

41
src/test/mir-opt/nll/liveness-drop-intra-block.rs
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@ -1,41 +0,0 @@
// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags:-Zborrowck=mir
#![allow(warnings)]
fn use_x(_: usize) -> bool { true }
fn main() {
let mut x = 22;
loop {
// Key point: `x` not live on entry to this basic block.
x = 55;
if use_x(x) { break; }
}
}
// END RUST SOURCE
// START rustc.main.nll.0.mir
// bb3: {
// | Live variables on entry to bb3[0]: []
// _1 = const 55usize;
// | Live variables on entry to bb3[1]: [_1]
// StorageLive(_3);
// | Live variables on entry to bb3[2]: [_1]
// StorageLive(_4);
// | Live variables on entry to bb3[3]: [_1]
// _4 = _1;
// | Live variables on entry to bb3[4]: [_4]
// _3 = const use_x(move _4) -> [return: bb4, unwind: bb1];
// | Live variables on exit from bb3: [_3]
// }
// END rustc.main.nll.0.mir

48
src/test/mir-opt/nll/liveness-interblock.rs
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@ -1,48 +0,0 @@
// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// compile-flags:-Zborrowck=mir
fn cond() -> bool { false }
fn make_live(_: usize) { }
fn make_dead() { }
fn main() {
let x = 5;
if cond() {
make_live(x);
} else {
// x should be dead on entry to this block
make_dead();
}
}
// END RUST SOURCE
// START rustc.main.nll.0.mir
// bb3: {
// | Live variables on entry to bb3[0]: [_1]
// StorageLive(_4);
// | Live variables on entry to bb3[1]: [_1]
// _4 = _1;
// | Live variables on entry to bb3[2]: [_4]
// _3 = const make_live(move _4) -> [return: bb5, unwind: bb1];
// | Live variables on exit from bb3: []
// }
// END rustc.main.nll.0.mir
// START rustc.main.nll.0.mir
// bb4: {
// | Live variables on entry to bb4[0]: []
// _5 = const make_dead() -> [return: bb6, unwind: bb1];
// | Live variables on exit from bb4: []
// }
// END rustc.main.nll.0.mir

58
src/test/mir-opt/nll/region-liveness-basic.rs
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@ -1,58 +0,0 @@
// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Basic test for liveness constraints: the region (`R1`) that appears
// in the type of `p` includes the points after `&v[0]` up to (but not
// including) the call to `use_x`. The `else` branch is not included.
// compile-flags:-Zborrowck=mir -Zverbose
// ^^^^^^^^^ force compiler to dump more region information
#![allow(warnings)]
fn use_x(_: usize) -> bool { true }
fn main() {
let mut v = [1, 2, 3];
let p = &v[0];
if true {
use_x(*p);
} else {
use_x(22);
}
}
// END RUST SOURCE
// START rustc.main.nll.0.mir
// | '_#2r | {bb2[0..=1], bb3[0..=1]}
// | '_#3r | {bb2[1], bb3[0..=1]}
// ...
// let _2: &'_#3r usize;
// END rustc.main.nll.0.mir
// START rustc.main.nll.0.mir
// bb2: {
// | Live variables on entry to bb2[0]: [_1, _3]
// _2 = &'_#2r _1[_3];
// | Live variables on entry to bb2[1]: [_2]
// switchInt(const true) -> [false: bb4, otherwise: bb3];
// | Live variables on exit from bb2: [_2]
// }
// END rustc.main.nll.0.mir
// START rustc.main.nll.0.mir
// bb3: {
// | Live variables on entry to bb3[0]: [_2]
// StorageLive(_7);
// | Live variables on entry to bb3[1]: [_2]
// _7 = (*_2);
// | Live variables on entry to bb3[2]: [_7]
// _6 = const use_x(move _7) -> [return: bb5, unwind: bb1];
// | Live variables on exit from bb3: []
// }
// END rustc.main.nll.0.mir

52
src/test/mir-opt/nll/region-liveness-two-disjoint-uses.rs
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@ -1,52 +0,0 @@
// Copyright 2012-2016 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
// Test for the subregion constraints. In this case, the region R3 on
// `p` includes two disjoint regions of the control-flow graph. The
// borrows in `&v[0]` and `&v[1]` each (in theory) have to outlive R3,
// but only at a particular point, and hence they wind up including
// distinct regions.
//
// FIXME(#43234) -- Well, this used to be true, but we modified NLL
// for the time being to not take location into account.
// compile-flags:-Zborrowck=mir -Zverbose
// ^^^^^^^^^ force compiler to dump more region information
#![allow(warnings)]
fn use_x(_: usize) -> bool { true }
fn main() {
let mut v = [1, 2, 3];
let mut p = &v[0];
if true {
use_x(*p);
} else {
use_x(22);
}
p = &v[1];
use_x(*p);
}
// END RUST SOURCE
// START rustc.main.nll.0.mir
// | '_#2r | {bb2[0..=1], bb3[0..=1], bb8[2..=4]}
// ...
// | '_#4r | {bb2[1], bb3[0..=1], bb8[1..=4]}
// | '_#5r | {bb2[1], bb3[0..=1], bb8[2..=4]}
// ...
// let mut _2: &'_#5r usize;
// ...
// _2 = &'_#2r _1[_3];
// ...
// _2 = &'_#4r (*_10);
// END rustc.main.nll.0.mir