Viewing file:  Wstringop-overflow-39.c (3.06 KB) -rw-r--r--
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/* PR middle-end/95667 - unintended warning for memset writing across multiple
members
{ dg-do compile }
{ dg-options "-O2 -Wall" }
{ dg-require-effective-target alloca } */
extern void sink (void*);
struct S1 { char a[3], b[5]; };
void warn_strcpy_s1 (void)
{
struct S1 *p = __builtin_malloc (sizeof *p);
char s[] = "1234567";
__builtin_strcpy (p->a, s); // { dg-warning "\\\[-Wstringop-overflow" }
sink (p);
}
void nowarn_memset_s1 (void)
{
struct S1 *p = __builtin_malloc (sizeof *p);
__builtin_memset (p->a, 0, 8); // { dg-bogus "\\\[-Wstringop-overflow" }
sink (p);
}
struct S2 { char a[2], b[2][2], c[3]; };
void nowarn_memset_s2 (void)
{
struct S2 *p = __builtin_malloc (sizeof *p);
__builtin_memset (p->a, 0, sizeof *p);
sink (p);
__builtin_memset (p->b, 0, 7);
sink (p);
__builtin_memset (&p->b[0], 0, 7);
sink (p);
__builtin_memset (&p->b[1], 0, 5);
sink (p);
__builtin_memset (&p->b[0][0], 0, 7);
sink (p);
__builtin_memset (&p->b[0][1], 0, 6);
sink (p);
__builtin_memset (&p->b[1][0], 0, 5);
sink (p);
__builtin_memset (&p->b[1][1], 0, 4);
sink (p);
}
void warn_memset_s2 (void)
{
const unsigned n = sizeof (struct S2);
struct S2 *p = __builtin_malloc (n);
/* These should trigger -Wstringop-overflow rather than -Warray-bounds
but the main purpose of the test is to verify the absence of warnings
above so the exact warning for these overflwing calls isn't important
here. */
__builtin_memset (p->a, 0, n + 1); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
__builtin_memset (p->b, 0, 8); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
__builtin_memset (&p->b[0], 0, 8); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
__builtin_memset (&p->b[0][0], 0, 8); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
__builtin_memset (&p->b[1], 0, 6); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
__builtin_memset (&p->b[0][1], 0, 7); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (p);
}
void nowarn_vl_struct (unsigned n)
{
if (n < 3 || 5 < n)
n = 3;
struct V { char a[3], b[n], c[7]; } v;
__builtin_memset (v.a, 0, 15);
sink (&v);
__builtin_memset (v.b, 0, 12);
sink (&v);
__builtin_memset (v.c, 0, 7);
sink (&v);
__builtin_memset (v.a, 0, 16); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (&v);
__builtin_memset (v.b, 0, 13); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" }
sink (&v);
/* The &V.C argument is represented as a variable offset from
the beginning of the allocated object and there's no good
way to figure out from its variable offset that it's base
is the C member:
s.1_12 = __builtin_alloca_with_align (prephitmp_24, 8);
_9 = s.1_12 + prephitmp_27;
__builtin_memset (_9, 0, 2);
*/
__builtin_memset (v.c, 0, 8); // { dg-warning "\\\[-Warray-bounds|-Wstringop-overflow" "pr?????" { xfail *-*-* } }
sink (&v);
}
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