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Add coverage to continue statements

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`continue` statements were missing coverage. This was particularly
noticeable in a match pattern that contained only a `continue`
statement, leaving the branch appear uncounted. This PR addresses the
problem and adds tests to prove it.
This commit is contained in:
Rich Kadel 2021-04-18 02:55:17 -07:00
parent 83ca4b7e60
commit 448e52d97c
5 changed files with 160 additions and 2 deletions
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10
compiler/rustc_mir_build/src/build/scope.rs
View file

@ -618,6 +618,16 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
} else {
assert!(value.is_none(), "`return` and `break` should have a destination");
// `continue` statements generate no MIR statement with the `continue` statement's Span,
// and the `InstrumentCoverage` statement will have no way to generate a coverage
// code region for the `continue` statement, unless we add a dummy `Assign` here:
let mut local_decl = LocalDecl::new(self.tcx.mk_unit(), span);
local_decl = local_decl.immutable();
let temp = self.local_decls.push(local_decl);
let temp_place = Place::from(temp);
self.cfg.push(block, Statement { source_info, kind: StatementKind::StorageLive(temp) });
self.cfg.push_assign_unit(block, source_info, temp_place, self.tcx);
self.cfg.push(block, Statement { source_info, kind: StatementKind::StorageDead(temp) });
}
let region_scope = self.scopes.breakable_scopes[break_index].region_scope;

4
src/test/mir-opt/loop_test.main.SimplifyCfg-promote-consts.after.mir
View file

@ -8,6 +8,7 @@ fn main() -> () {
let mut _4: !; // in scope 0 at $DIR/loop_test.rs:13:5: 16:6
let mut _5: (); // in scope 0 at $DIR/loop_test.rs:6:1: 17:2
let _6: i32; // in scope 0 at $DIR/loop_test.rs:14:13: 14:14
let _7: (); // in scope 0 at $DIR/loop_test.rs:15:9: 15:17
scope 1 {
debug x => _6; // in scope 1 at $DIR/loop_test.rs:14:13: 14:14
}
@ -42,6 +43,9 @@ fn main() -> () {
StorageLive(_6); // scope 0 at $DIR/loop_test.rs:14:13: 14:14
_6 = const 1_i32; // scope 0 at $DIR/loop_test.rs:14:17: 14:18
FakeRead(ForLet(None), _6); // scope 0 at $DIR/loop_test.rs:14:13: 14:14
StorageLive(_7); // scope 1 at $DIR/loop_test.rs:15:9: 15:17
_7 = const (); // scope 1 at $DIR/loop_test.rs:15:9: 15:17
StorageDead(_7); // scope 1 at $DIR/loop_test.rs:15:9: 15:17
StorageDead(_6); // scope 0 at $DIR/loop_test.rs:16:5: 16:6
goto -> bb3; // scope 0 at $DIR/loop_test.rs:1:1: 1:1
}

75
src/test/run-make-fulldeps/coverage-reports/expected_show_coverage.continue.txt Normal file
View file

@ -0,0 +1,75 @@
1| |#![allow(unused_assignments, unused_variables)]
2| |
3| 1|fn main() {
4| 1| let is_true = std::env::args().len() == 1;
5| 1|
6| 1| let mut x = 0;
7| 11| for _ in 0..10 {
^10
8| 10| match is_true {
9| | true => {
10| 10| continue;
11| | }
12| 0| _ => {
13| 0| x = 1;
14| 0| }
15| 0| }
16| 0| x = 3;
17| | }
18| 11| for _ in 0..10 {
^10
19| 10| match is_true {
20| 0| false => {
21| 0| x = 1;
22| 0| }
23| | _ => {
24| 10| continue;
25| | }
26| | }
27| 0| x = 3;
28| | }
29| 11| for _ in 0..10 {
^10
30| 10| match is_true {
31| 10| true => {
32| 10| x = 1;
33| 10| }
34| | _ => {
35| 0| continue;
36| | }
37| | }
38| 10| x = 3;
39| | }
40| 11| for _ in 0..10 {
^10
41| 10| if is_true {
42| 10| continue;
43| 0| }
44| 0| x = 3;
45| | }
46| 11| for _ in 0..10 {
^10
47| 10| match is_true {
48| 0| false => {
49| 0| x = 1;
50| 0| }
51| 10| _ => {
52| 10| let _ = x;
53| 10| }
54| | }
55| 10| x = 3;
56| | }
57| 1| for _ in 0..10 {
58| 1| match is_true {
59| 0| false => {
60| 0| x = 1;
61| 0| }
62| | _ => {
63| 1| break;
64| | }
65| | }
66| 0| x = 3;
67| | }
68| | let _ = x;
69| 1|}

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

@ -19,12 +19,12 @@
18| 2| println!("used_only_from_bin_crate_generic_function with {:?}", arg);
19| 2|}
------------------
| used_crate::used_only_from_bin_crate_generic_function::<&alloc::vec::Vec<i32>>:
| used_crate::used_only_from_bin_crate_generic_function::<&str>:
| 17| 1|pub fn used_only_from_bin_crate_generic_function<T: Debug>(arg: T) {
| 18| 1| println!("used_only_from_bin_crate_generic_function with {:?}", arg);
| 19| 1|}
------------------
| used_crate::used_only_from_bin_crate_generic_function::<&str>:
| used_crate::used_only_from_bin_crate_generic_function::<&alloc::vec::Vec<i32>>:
| 17| 1|pub fn used_only_from_bin_crate_generic_function<T: Debug>(arg: T) {
| 18| 1| println!("used_only_from_bin_crate_generic_function with {:?}", arg);
| 19| 1|}

69
src/test/run-make-fulldeps/coverage/continue.rs Normal file
View file

@ -0,0 +1,69 @@
#![allow(unused_assignments, unused_variables)]
fn main() {
let is_true = std::env::args().len() == 1;
let mut x = 0;
for _ in 0..10 {
match is_true {
true => {
continue;
}
_ => {
x = 1;
}
}
x = 3;
}
for _ in 0..10 {
match is_true {
false => {
x = 1;
}
_ => {
continue;
}
}
x = 3;
}
for _ in 0..10 {
match is_true {
true => {
x = 1;
}
_ => {
continue;
}
}
x = 3;
}
for _ in 0..10 {
if is_true {
continue;
}
x = 3;
}
for _ in 0..10 {
match is_true {
false => {
x = 1;
}
_ => {
let _ = x;
}
}
x = 3;
}
for _ in 0..10 {
match is_true {
false => {
x = 1;
}
_ => {
break;
}
}
x = 3;
}
let _ = x;
}