blob: 7e44beb18a2e96c8029a5bf61974308ba0fa383f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
|
// Copyright 2015 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.
use rustc::mir::repr::*;
/// Update basic block ids in all terminators using the given replacements,
/// useful e.g. after removal of several basic blocks to update all terminators
/// in a single pass
pub fn update_basic_block_ids(mir: &mut Mir, replacements: &[BasicBlock]) {
for bb in mir.all_basic_blocks() {
for target in mir.basic_block_data_mut(bb).terminator_mut().successors_mut() {
*target = replacements[target.index()];
}
}
}
/// Mass removal of basic blocks to keep the ID-remapping cheap.
pub fn retain_basic_blocks(mir: &mut Mir, keep: &[bool]) {
let num_blocks = mir.basic_blocks.len();
// Check that we have a usage flag for every block
assert_eq!(num_blocks, keep.len());
let first_dead = match keep.iter().position(|&k| !k) {
None => return,
Some(first_dead) => first_dead,
};
// `replacements` maps the old block ids to the new ones
let mut replacements: Vec<_> = (0..num_blocks).map(BasicBlock::new).collect();
let mut dead = 0;
for i in first_dead..num_blocks {
if keep[i] {
replacements[i] = BasicBlock::new(i - dead);
mir.basic_blocks.swap(i, i - dead);
} else {
dead += 1;
}
}
mir.basic_blocks.truncate(num_blocks - dead);
update_basic_block_ids(mir, &replacements);
}
|
