| Issue |
52786
|
| Summary |
[-Wuninitialized, -Wsometimes-uninitialized] false positive on nested calls that will never return
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
stargateaudio
|
Test case:
```
#include <stdio.h>
#include <stdlib.h>
void custom_abort(){
printf("Called custom_abort");
exit(1);
}
int main(int argc, char**argv){
int some_value;
custom_abort();
// This code is unreachable
printf("some_value: %i\n", some_value);
return 0;
}
```
Output:
```
$ clang -Wall test.c
test.c:12:32: warning: variable 'some_value' is uninitialized when used here [-Wuninitialized]
printf("some_value: %i\n", some_value);
^~~~~~~~~~
test.c:10:19: note: initialize the variable 'some_value' to silence this warning
int some_value;
^
= 0
1 warning generated.
```
Of course, that test case is greatly oversimplified, the more important use-case is when we conditionally abort the program instead of initializing (-Wsometimes-uninitialized). Note that the warning is not generated if `abort` or `exit` is called directly in the `main` function instead of `custom_abort();`. If the nested call to `abort()`, `exit()`, etc... is conditional, additional analysis may be required to determine if the arguments being passed to the function will result in the call returning or not.
```
$ clang -v
clang version 13.0.0 (Fedora 13.0.0-3.fc35)
Target: x86_64-redhat-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/11
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-redhat-linux/11
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
```
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