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|
1| |#![allow(unused_assignments, dead_code)]
2| |
3| |// compile-flags: --edition=2018 -C opt-level=1
4| |
5| 1|async fn c(x: u8) -> u8 {
6| 1| if x == 8 {
7| 1| 1
8| | } else {
9| 0| 0
10| | }
11| 1|}
12| |
13| 0|async fn d() -> u8 { 1 }
14| |
15| 0|async fn e() -> u8 { 1 } // unused function; executor does not block on `g()`
16| |
17| 1|async fn f() -> u8 { 1 }
18| |
19| 0|async fn foo() -> [bool; 10] { [false; 10] } // unused function; executor does not block on `h()`
20| |
21| 1|pub async fn g(x: u8) {
22| 0| match x {
23| 0| y if e().await == y => (),
24| 0| y if f().await == y => (),
25| 0| _ => (),
26| | }
27| 0|}
28| |
29| 1|async fn h(x: usize) { // The function signature is counted when called, but the body is not
30| 0| // executed (not awaited) so the open brace has a `0` count (at least when
31| 0| // displayed with `llvm-cov show` in color-mode).
32| 0| match x {
33| 0| y if foo().await[y] => (),
34| 0| _ => (),
35| | }
36| 0|}
37| |
38| 1|async fn i(x: u8) { // line coverage is 1, but there are 2 regions:
39| 1| // (a) the function signature, counted when the function is called; and
40| 1| // (b) the open brace for the function body, counted once when the body is
41| 1| // executed asynchronously.
42| 1| match x {
43| 1| y if c(x).await == y + 1 => { d().await; }
^0 ^0 ^0 ^0
44| 1| y if f().await == y + 1 => (),
^0 ^0 ^0
45| 1| _ => (),
46| | }
47| 1|}
48| |
49| 1|fn j(x: u8) {
50| 1| // non-async versions of `c()`, `d()`, and `f()` to make it similar to async `i()`.
51| 1| fn c(x: u8) -> u8 {
52| 1| if x == 8 {
53| 1| 1 // This line appears covered, but the 1-character expression span covering the `1`
^0
54| 1| // is not executed. (`llvm-cov show` displays a `^0` below the `1` ). This is because
55| 1| // `fn j()` executes the open brace for the funciton body, followed by the function's
56| 1| // first executable statement, `match x`. Inner function declarations are not
57| 1| // "visible" to the MIR for `j()`, so the code region counts all lines between the
58| 1| // open brace and the first statement as executed, which is, in a sense, true.
59| 1| // `llvm-cov show` overcomes this kind of situation by showing the actual counts
60| 1| // of the enclosed coverages, (that is, the `1` expression was not executed, and
61| 1| // accurately displays a `0`).
62| 1| } else {
63| 1| 0
64| 1| }
65| 1| }
66| 1| fn d() -> u8 { 1 } // inner function is defined in-line, but the function is not executed
^0
67| 1| fn f() -> u8 { 1 }
68| 1| match x {
69| 1| y if c(x) == y + 1 => { d(); }
^0 ^0
70| 1| y if f() == y + 1 => (),
^0 ^0
71| 1| _ => (),
72| | }
73| 1|}
74| |
75| 0|fn k(x: u8) { // unused function
76| 0| match x {
77| 0| 1 => (),
78| 0| 2 => (),
79| 0| _ => (),
80| | }
81| 0|}
82| |
83| 1|fn l(x: u8) {
84| 1| match x {
85| 0| 1 => (),
86| 0| 2 => (),
87| 1| _ => (),
88| | }
89| 1|}
90| |
91| 1|async fn m(x: u8) -> u8 { x - 1 }
^0
92| |
93| 1|fn main() {
94| 1| let _ = g(10);
95| 1| let _ = h(9);
96| 1| let mut future = Box::pin(i(8));
97| 1| j(7);
98| 1| l(6);
99| 1| let _ = m(5);
100| 1| executor::block_on(future.as_mut());
101| 1|}
102| |
103| |mod executor {
104| | use core::{
105| | future::Future,
106| | pin::Pin,
107| | task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
108| | };
109| |
110| 1| pub fn block_on<F: Future>(mut future: F) -> F::Output {
111| 1| let mut future = unsafe { Pin::new_unchecked(&mut future) };
112| 1| use std::hint::unreachable_unchecked;
113| 1| static VTABLE: RawWakerVTable = RawWakerVTable::new(
114| 1| |_| unsafe { unreachable_unchecked() }, // clone
^0
115| 1| |_| unsafe { unreachable_unchecked() }, // wake
^0
116| 1| |_| unsafe { unreachable_unchecked() }, // wake_by_ref
^0
117| 1| |_| (),
118| 1| );
119| 1| let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
120| 1| let mut context = Context::from_waker(&waker);
121| |
122| | loop {
123| 1| if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
124| 1| break val;
125| 0| }
126| | }
127| 1| }
128| |}
|
