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
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
|
#![allow(unused_assignments, dead_code)]
// compile-flags: --edition=2018 -C opt-level=1 # fix in rustc_mir/monomorphize/partitioning/mod.rs
async fn c(x: u8) -> u8 {
if x == 8 {
1
} else {
0
}
}
async fn d() -> u8 { 1 } // should have a coverage count `0` (see below)
async fn e() -> u8 { 1 } // unused function; executor does not block on `g()`
async fn f() -> u8 { 1 }
async fn foo() -> [bool; 10] { [false; 10] } // unused function; executor does not block on `h()`
pub async fn g(x: u8) {
match x {
y if e().await == y => (),
y if f().await == y => (),
_ => (),
}
}
async fn h(x: usize) { // The function signature is counted when called, but the body is not
// executed (not awaited) so the open brace has a `0` count (at least when
// displayed with `llvm-cov show` in color-mode).
match x {
y if foo().await[y] => (),
_ => (),
}
}
async fn i(x: u8) { // line coverage is 1, but there are 2 regions:
// (a) the function signature, counted when the function is called; and
// (b) the open brace for the function body, counted once when the body is
// executed asynchronously.
match x {
y if c(x).await == y + 1 => { d().await; }
y if f().await == y + 1 => (),
_ => (),
}
}
fn j(x: u8) {
// non-async versions of `c()`, `d()`, and `f()` to make it similar to async `i()`.
fn c(x: u8) -> u8 {
if x == 8 {
1 // This line appears covered, but the 1-character expression span covering the `1`
// is not executed. (`llvm-cov show` displays a `^0` below the `1` ). This is because
// `fn j()` executes the open brace for the funciton body, followed by the function's
// first executable statement, `match x`. Inner function declarations are not
// "visible" to the MIR for `j()`, so the code region counts all lines between the
// open brace and the first statement as executed, which is, in a sense, true.
// `llvm-cov show` overcomes this kind of situation by showing the actual counts
// of the enclosed coverages, (that is, the `1` expression was not executed, and
// accurately displays a `0`).
} else {
0
}
}
fn d() -> u8 { 1 }
fn f() -> u8 { 1 }
match x {
y if c(x) == y + 1 => { d(); }
y if f() == y + 1 => (),
_ => (),
}
}
fn k(x: u8) { // unused function
match x {
1 => (),
2 => (),
_ => (),
}
}
fn l(x: u8) {
match x {
1 => (),
2 => (),
_ => (),
}
}
async fn m(x: u8) -> u8 { x - 1 }
fn main() {
let _ = g(10);
let _ = h(9);
let mut future = Box::pin(i(8));
j(7);
l(6);
let _ = m(5);
executor::block_on(future.as_mut());
}
mod executor {
use core::{
future::Future,
pin::Pin,
task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
};
pub fn block_on<F: Future>(mut future: F) -> F::Output {
let mut future = unsafe { Pin::new_unchecked(&mut future) };
static VTABLE: RawWakerVTable = RawWakerVTable::new(
|_| unimplemented!("clone"),
|_| unimplemented!("wake"),
|_| unimplemented!("wake_by_ref"),
|_| (),
);
let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
let mut context = Context::from_waker(&waker);
loop {
if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
break val;
}
}
}
}
// `llvm-cov show` shows no coverage results for the `d()`, even though the
// crate's LLVM IR shows the function exists and has an InstrProf PGO counter,
// and appears to be registered like all other counted functions.
//
// `llvm-cov show --debug` output shows there is at least one `Counter` for this
// line, but counters do not appear in the `Combined regions` section (unlike
// `f()`, which is similar, but does appear in `Combined regions`, and does show
// coverage). The only difference is, `f()` is awaited, but the call to await
// `d()` is not reached. (Note: `d()` will appear in coverage if the test is
// modified to cause it to be awaited.)
|
