https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81437
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|--- |11.0
Blocks|88443 |97048
Status|NEW |RESOLVED
Known to fail|10.0 |10.2.0
Known to work| |11.0
Resolution|--- |FIXED
Assignee|unassigned at gcc dot gnu.org |msebor at gcc dot
gnu.org
Summary|missing -Wstringop-overflow |missing -Wstringop-overread
|reading past the end of a |reading past the end of a
|string |string
--- Comment #5 from Martin Sebor <msebor at gcc dot gnu.org> ---
GCC 11 diagnoses all instances of the problem with the new -Wstringop-overead
warning, both in the test case in comment #0 as well in comment #4:
$ gcc -O2 -S pr81437.c
pr81437.c: In function ‘f’:
pr81437.c:5:3: warning: ‘__builtin_memcpy’ reading between 1 and 4294967295
bytes from a region of size 0 [-Wstringop-overread]
5 | __builtin_memcpy (d, a + 4, n); // warning (ok)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pr81437.c:3:14: note: at offset 4 into source object ‘a’
3 | const char a[] = "123";
| ^
pr81437.c: In function ‘g’:
pr81437.c:12:3: warning: ‘__builtin_memcpy’ reading 1 byte from a region of
size 0 [-Wstringop-overread]
12 | __builtin_memcpy (d, a + 4, n); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
pr81437.c:10:14: note: at offset 4 into source object ‘a’
10 | const char a[] = "123";
| ^
pr81437.c: In function ‘h’:
pr81437.c:18:3: warning: ‘__builtin_strcpy’ reading 1 or more bytes from a
region of size 0 [-Wstringop-overread]
18 | __builtin_strcpy (d, a + 4); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
pr81437.c:17:14: note: at offset 4 into source object ‘a’
17 | const char a[] = "123";
| ^
pr81437.c: In function ‘fx’:
pr81437.c:26:10: warning: ‘__builtin_strcmp’ reading between 1 and 4 bytes from
a region of size 0 [-Wstringop-overread]
26 | return __builtin_strcmp (a, &a[4]); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
pr81437.c:22:6: note: at offset 4 into source object ‘a’
22 | char a[4];
| ^
pr81437.c: In function ‘gx’:
pr81437.c:31:10: warning: ‘__builtin_puts’ reading between 1 and 4 bytes from a
region of size 0 [-Wstringop-overread]
31 | return __builtin_puts (&a[4]); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~
pr81437.c:22:6: note: at offset 4 into source object ‘a’
22 | char a[4];
| ^
pr81437.c: In function ‘fc4’:
pr81437.c:26:10: warning: ‘__builtin_strcmp’ reading between 1 and 4 bytes from
a region of size 0 [-Wstringop-overread]
26 | return __builtin_strcmp (a, &a[4]); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
pr81437.c:22:6: note: at offset 4 into source object ‘a’
22 | char a[4];
| ^
pr81437.c: In function ‘gc4’:
pr81437.c:31:10: warning: ‘__builtin_puts’ reading between 1 and 4 bytes from a
region of size 0 [-Wstringop-overread]
31 | return __builtin_puts (&a[4]); // missing warning
| ^~~~~~~~~~~~~~~~~~~~~~
pr81437.c:22:6: note: at offset 4 into source object ‘a’
22 | char a[4];
| ^
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88443
[Bug 88443] [meta-bug] bogus/missing -Wstringop-overflow warnings
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97048
[Bug 97048] [meta-bug] bogus/missing -Wstringop-overread warnings
