https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97495
Bug ID: 97495
Summary: -Wstringop-overflow where -Warray-bounds would be more
appropriate
Product: gcc
Version: 11.0
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: ---
-Wstringop-overflow is documented to "Warn for calls to string manipulation
functions such as memcpy and strcpy that are determined to overflow the
destination buffer" but in GCC 11 it's issued even for user-defined functions
that don't manipulate strings. GCC should issue -Warray-bounds for those
instead. In addition, mentioning array indices rather than byte counts might
make the warnings easier to interpret.
$ cat z.c && gcc -O2 -S -Wall z.c
void f (int[static 4]);
void g (void)
{
int a[2];
f (a);
}
z.c: In function ‘g’:
z.c:6:3: warning: ‘f’ accessing 16 bytes in a region of size 8
[-Wstringop-overflow=]
6 | f (a);
| ^~~~~
z.c:6:3: note: referencing argument 1 of type ‘int *’
z.c:1:6: note: in a call to function ‘f’
1 | void f (int[static 4]);
| ^
Clang issues -Warray-bounds as expected:
z.c:6:3: warning: array argument is too small; contains 2 elements, callee
requires at least 4 [-Warray-bounds]
f (a);
^ ~
z.c:1:12: note: callee declares array parameter as static here
void f (int[static 4]);
^~~~~~~~~~
1 warning generated.
