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Auto merge of #84797 - richkadel:cover-unreachable-statements, r=tmandry

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Report coverage `0` of dead blocks

Fixes: #84018

With `-Z instrument-coverage`, coverage reporting of dead blocks
(for example, blocks dropped because a conditional branch is dropped,
based on const evaluation) is now supported.

If `instrument-coverage` is enabled, `simplify::remove_dead_blocks()`
finds all dropped coverage `Statement`s and adds their `code_region`s as
`Unreachable` coverage `Statement`s to the `START_BLOCK`, so they are
still included in the coverage map.

Check out the resulting changes in the test coverage reports in this PR (in [commit 1](https://github.com/rust-lang/rust/pull/84797/commits/0b0d293c7c46bdadf80e5304a667e34c53c0cf7e)).

r? `@tmandry`
cc: `@wesleywiser`
This commit is contained in:
bors 2021-05-07 10:06:40 +00:00
commit e5f83d24ae
21 changed files with 102 additions and 65 deletions
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1
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.async2.txt
View file

@ -12,6 +12,7 @@
12| 1| if b {
13| 1| println!("non_async_func println in block");
14| 1| }
^0
15| 1|}
16| |
17| |

8
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.conditions.txt
View file

@ -5,6 +5,7 @@
5| 1| if true {
6| 1| countdown = 10;
7| 1| }
^0
8| |
9| | const B: u32 = 100;
10| 1| let x = if countdown > 7 {
@ -24,6 +25,7 @@
24| 1| if true {
25| 1| countdown = 10;
26| 1| }
^0
27| |
28| 1| if countdown > 7 {
29| 1| countdown -= 4;
@ -42,6 +44,7 @@
41| 1| if true {
42| 1| countdown = 10;
43| 1| }
^0
44| |
45| 1| if countdown > 7 {
46| 1| countdown -= 4;
@ -54,13 +57,14 @@
53| | } else {
54| 0| return;
55| | }
56| | } // Note: closing brace shows uncovered (vs. `0` for implicit else) because condition literal
57| | // `true` was const-evaluated. The compiler knows the `if` block will be executed.
56| 0| }
57| |
58| |
59| 1| let mut countdown = 0;
60| 1| if true {
61| 1| countdown = 1;
62| 1| }
^0
63| |
64| 1| let z = if countdown > 7 {
^0

4
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.doctest.txt
View file

@ -9,7 +9,7 @@
8| 1|//! assert_eq!(1, 1);
9| |//! } else {
10| |//! // this is not!
11| |//! assert_eq!(1, 2);
11| 0|//! assert_eq!(1, 2);
12| |//! }
13| 1|//! ```
14| |//!
@ -84,7 +84,7 @@
74| 1| if true {
75| 1| assert_eq!(1, 1);
76| | } else {
77| | assert_eq!(1, 2);
77| 0| assert_eq!(1, 2);
78| | }
79| 1|}
80| |

10
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.drop_trait.txt
View file

@ -19,11 +19,11 @@
19| 1| if true {
20| 1| println!("Exiting with error...");
21| 1| return Err(1);
22| | }
23| |
24| | let _ = Firework { strength: 1000 };
25| |
26| | Ok(())
22| 0| }
23| 0|
24| 0| let _ = Firework { strength: 1000 };
25| 0|
26| 0| Ok(())
27| 1|}
28| |
29| |// Expected program output:

18
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.generics.txt
View file

@ -52,15 +52,15 @@
30| 1| if true {
31| 1| println!("Exiting with error...");
32| 1| return Err(1);
33| | } // The remaining lines below have no coverage because `if true` (with the constant literal
34| | // `true`) is guaranteed to execute the `then` block, which is also guaranteed to `return`.
35| | // Thankfully, in the normal case, conditions are not guaranteed ahead of time, and as shown
36| | // in other tests, the lines below would have coverage (which would show they had `0`
37| | // executions, assuming the condition still evaluated to `true`).
38| |
39| | let _ = Firework { strength: 1000 };
40| |
41| | Ok(())
33| 0| }
34| 0|
35| 0|
36| 0|
37| 0|
38| 0|
39| 0| let _ = Firework { strength: 1000 };
40| 0|
41| 0| Ok(())
42| 1|}
43| |
44| |// Expected program output:

38
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.loops_branches.txt
View file

@ -9,23 +9,23 @@
9| 1| fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
10| 1| if true {
11| 1| if false {
12| | while true {
13| | }
12| 0| while true {
13| 0| }
14| 1| }
15| 1| write!(f, "error")?;
^0
16| | } else {
17| | }
15| 1| write!(f, "cool")?;
^0
16| 0| } else {
17| 0| }
18| |
19| 10| for i in 0..10 {
20| 10| if true {
21| 10| if false {
22| | while true {}
22| 0| while true {}
23| 10| }
24| 10| write!(f, "error")?;
^0
25| | } else {
26| | }
24| 10| write!(f, "cool")?;
^0
25| 0| } else {
26| 0| }
27| | }
28| 1| Ok(())
29| 1| }
@ -36,21 +36,21 @@
34| |impl std::fmt::Display for DisplayTest {
35| 1| fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
36| 1| if false {
37| | } else {
37| 0| } else {
38| 1| if false {
39| | while true {}
39| 0| while true {}
40| 1| }
41| 1| write!(f, "error")?;
^0
41| 1| write!(f, "cool")?;
^0
42| | }
43| 10| for i in 0..10 {
44| 10| if false {
45| | } else {
45| 0| } else {
46| 10| if false {
47| | while true {}
47| 0| while true {}
48| 10| }
49| 10| write!(f, "error")?;
^0
49| 10| write!(f, "cool")?;
^0
50| | }
51| | }
52| 1| Ok(())

2
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.tight_inf_loop.txt
View file

@ -1,6 +1,6 @@
1| 1|fn main() {
2| 1| if false {
3| | loop {}
3| 0| loop {}
4| 1| }
5| 1|}

4
src/test/run-make-fulldeps/coverage/conditions.rs
View file

@ -53,8 +53,8 @@ fn main() {
} else {
return;
}
} // Note: closing brace shows uncovered (vs. `0` for implicit else) because condition literal
// `true` was const-evaluated. The compiler knows the `if` block will be executed.
}
let mut countdown = 0;
if true {

10
src/test/run-make-fulldeps/coverage/generics.rs
View file

@ -30,11 +30,11 @@ fn main() -> Result<(),u8> {
if true {
println!("Exiting with error...");
return Err(1);
} // The remaining lines below have no coverage because `if true` (with the constant literal
// `true`) is guaranteed to execute the `then` block, which is also guaranteed to `return`.
// Thankfully, in the normal case, conditions are not guaranteed ahead of time, and as shown
// in other tests, the lines below would have coverage (which would show they had `0`
// executions, assuming the condition still evaluated to `true`).
}
let _ = Firework { strength: 1000 };

8
src/test/run-make-fulldeps/coverage/loops_branches.rs
View file

@ -12,7 +12,7 @@ impl std::fmt::Debug for DebugTest {
while true {
}
}
write!(f, "error")?;
write!(f, "cool")?;
} else {
}
@ -21,7 +21,7 @@ impl std::fmt::Debug for DebugTest {
if false {
while true {}
}
write!(f, "error")?;
write!(f, "cool")?;
} else {
}
}
@ -38,7 +38,7 @@ impl std::fmt::Display for DisplayTest {
if false {
while true {}
}
write!(f, "error")?;
write!(f, "cool")?;
}
for i in 0..10 {
if false {
@ -46,7 +46,7 @@ impl std::fmt::Display for DisplayTest {
if false {
while true {}
}
write!(f, "error")?;
write!(f, "cool")?;
}
}
Ok(())