<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/92108>92108</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            ubsan complains on rpcgen-generated code, gcc's one silent
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          stsp
      </td>
    </tr>
</table>

<pre>
    It appears, clang's ubsan complains on
an rpcgen-generated code, while gcc's
ubsan is silent.
The code roughly looks like this (reduced test-case):
```
#include <stddef.h>

struct svc_req;

static int
_a_1 (char * *argp, void *result, struct svc_req *rqstp)
{
        return 0;
}

int main()
{
        int (*local)(char *, void *, struct svc_req *);
        local = (int (*) (char *, void *,  struct svc_req *))_a_1;
        return local(NULL, NULL, NULL);
}
```

Now do this:
```
$ gcc -Wall -fsanitize=undefined tst.c 
$ ./a.out
$ clang -Wall -fsanitize=undefined tst.c 
$ ./a.out
tst.c:15:9: runtime error: call to function _a_1 through pointer to incorrect function type 'int (*)(char *, void *, struct svc_req *)'
tst.c: note: _a_1 defined here
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior tst.c:15:9
```

As can be seen, only clang complained.
I don't know if it is a real UB or a false-positive.
But as gcc keeps silence, I assume this is
a false-positive.
There is no way to "just fix" the code, as it
is generated by rpcgen.
</pre>
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