Viewing file:  Wuse-after-free-2.c (2.5 KB) -rw-r--r--
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/* PR middle-end/104232 - spurious -Wuse-after-free after conditional free
{ dg-do compile }
{ dg-options "-O2 -Wall -fno-tree-loop-distribute-patterns" } */
void free (void*);
void sink (void*);
void nowarn_cond_2 (char *p0, char *q0, int i)
{
char *r = i ? p0 : q0;
free (p0);
/* The use of a PHI operand could be diagnosed using the "maybe" form
of the warning at level 2 but it's not done. If it ever changes
this test and those below will need to be updated. */
sink (r);
}
void nowarn_cond_2_null (char *p0, int i)
{
char *r = i ? p0 : 0;
free (p0);
sink (r);
}
void nowarn_cond_3 (char *p0, char *q0, int i)
{
char *r = i < 0 ? p0 - 1 : 0 < i ? p0 + 1 : q0;
free (p0);
sink (r);
}
void nowarn_cond_3_null (char *p0, int i)
{
char *r = i < 0 ? p0 - 1 : 0 < i ? p0 + 1 : 0;
free (p0);
sink (r);
}
void nowarn_cond_4 (char *p0, char *q0, int i)
{
char *r = i < -1 ? p0 - 2 : i < 0 ? p0 - 1 : 1 < i ? p0 + 1 : q0;
free (p0);
sink (r);
}
int nowarn_cond_loop (char *p)
{
char *q = p;
while (*q)
{
if (*q == 'x')
{
q = "";
break;
}
++q;
}
free (p);
return *q;
}
void warn_cond_2_cst (char *p, int i)
{
/* Same as nowarn_cond_2() above but with R being derived only from
P, which means that any R's use after P has been freed should be
diagnosed. */
char *r = i ? p + 1 : p + 2;
free (p); // { dg-message "call to 'free'" }
sink (r); // { dg-warning "pointer used after 'free'" }
}
void warn_cond_2_var (char *p, int i, int j)
{
char *r = i ? p + i : p + j;
free (p); // { dg-message "call to 'free'" }
sink (r); // { dg-warning "pointer used after 'free'" }
}
void warn_cond_3_var (char *p0, int i, int j)
{
char *r = i < 0 ? p0 - i : 0 < i ? p0 + j : p0 + i + j;
free (p0); // { dg-message "call to 'free'" }
sink (r + 1); // { dg-warning "pointer used after 'free'" }
}
int warn_cond_4 (char *p0, char *q0, int i)
{
char *r = i < -1 ? p0 - 2 : i < 0 ? p0 - 1 : 1 < i ? p0 + 2 : p0 + 1;
free (p0); // { dg-message "call to 'free'" }
return *r; // { dg-warning "pointer used after 'free'" }
}
int warn_cond_loop (char *p)
{
char *q = p;
/* -fno-tree-loop-distribute-patterns ensures this does not get converted
into rawmemchr (making q and p unrelated). */
while (*q)
++q;
free (p); // { dg-message "call to 'free'" }
return *q; // { dg-warning "pointer 'q' used after 'free'" }
}
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