https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95278
Bug ID: 95278
Summary: attribute nonstring effect on arguments in function
declaration that's not a definition
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
strlen calls in both functions below should be diagnosed because the
declaration with the attribute is likely to be in a header and thus come first,
and it's what determines what calls can be diagnosed. Unfortunately, the more
likely case is not diagnosed.
$ cat z.c && gcc -S -Wall -Wextra z.c
int f (const char *);
int f (const char __attribute__ ((nonstring)) *p)
{
return __builtin_strlen (p); // warning (good)
}
int g (const char __attribute__ ((nonstring))*);
int g (const char *p)
{
return __builtin_strlen (p); // missing warning
}
z.c: In function ‘f’:
z.c:5:10: warning: ‘__builtin_strlen’ argument 1 declared attribute ‘nonstring’
[-Wstringop-overflow=]
5 | return __builtin_strlen (p); // warning (good)
| ^~~~~~~~~~~~~~~~~~~~
z.c:3:48: note: argument ‘p’ declared here
3 | int f (const char __attribute__ ((nonstring)) *p)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
