| Issue |
124296
|
| Summary |
[coverage] __noreturn__ attribute leads to incorrect coverage report
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
justincady
|
The `__noreturn__` attribute appears to invalidate coverage of the following line, whereas `_Noreturn` demonstrates correct behavior.
```c
// coverage.c
#include <stdio.h>
__attribute__ ((__noreturn__)) void foo(void) { while (1); }
_Noreturn void bar(void) { while (1); }
int main(int argc, char **argv) {
int rc = ({ if (argc > 3) foo(); 0; });
printf("coverage after foo is missing\n");
int rc2 = ({ if (argc > 3) bar(); 0; });
printf("coverage after bar is present\n");
return rc + rc2;
}
```
```bash
# build.sh
/usr/bin/clang --version | /bin/grep "clang version"
/usr/bin/clang -fprofile-instr-generate -fcoverage-mapping coverage.c -o coverage
./coverage
/usr/bin/llvm-profdata merge -sparse default.profraw -o default.profdata
/usr/bin/llvm-cov show ./coverage -instr-profile=""
```
Running the script:
```
$ ./build.sh
clang version 19.1.1 (Red Hat, Inc. 19.1.1-5.el10)
coverage after foo is missing
coverage after bar is present
1| |#include <stdio.h>
2| |
3| 0|__attribute__ ((__noreturn__)) void foo(void) { while (1); }
4| 0|_Noreturn void bar(void) { while (1); }
5| |
6| 1|int main(int argc, char **argv) {
7| 1| int rc = ({ if (argc > 3) foo(); 0; });
8| 0| printf("coverage after foo is missing\n");
9| |
10| 1| int rc2 = ({ if (argc > 3) bar(); 0; });
11| 1| printf("coverage after bar is present\n");
12| 1| return rc + rc2;
13| 1|}
$
```
- Line 8 is reported as uncovered, though it prints as expected. (incorrect behavior)
- Line 11 is reported as covered, and prints as expected. (correct behavior)
This seems like a bug connected to `__noreturn__`. FWIW I also tested this in C++ and observed the same results.
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