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* [Bug middle-end/102934] New: missing warning passing address of first member to free()
@ 2021-10-25 17:19 msebor at gcc dot gnu.org
2021-10-25 17:20 ` [Bug middle-end/102934] " msebor at gcc dot gnu.org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: msebor at gcc dot gnu.org @ 2021-10-25 17:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102934
Bug ID: 102934
Summary: missing warning passing address of first member to
free()
Product: gcc
Version: 12.0
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: ---
GCC diagnoses the first invalid call to free() below but fails to diagnose the
second. The problem is due to the warning using Object Size Type 0 (whole
objects) rather than 1 (subobjects) to determine the identity of the object
being freed.
$ cat z.c && gcc -O2 -S -Wall z.c
struct A { int i, a[2]; };
void f (struct A *p)
{
__builtin_free (p->a); // -Wfree-nonheap-object (good)
}
struct B { int a[2], j; };
void g (struct B *p)
{
__builtin_free (p->a); // missing warning
}
z.c: In function ‘f’:
z.c:5:3: warning: ‘__builtin_free’ called on pointer ‘p’ with nonzero offset 4
[-Wfree-nonheap-object]
5 | __builtin_free (p->a); // -Wfree-nonheap-object (good)
| ^~~~~~~~~~~~~~~~~~~~~
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/102934] missing warning passing address of first member to free()
2021-10-25 17:19 [Bug middle-end/102934] New: missing warning passing address of first member to free() msebor at gcc dot gnu.org
@ 2021-10-25 17:20 ` msebor at gcc dot gnu.org
2021-10-26 7:07 ` rguenth at gcc dot gnu.org
2022-01-26 17:19 ` msebor at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: msebor at gcc dot gnu.org @ 2021-10-25 17:20 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102934
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Ever confirmed|0 |1
Assignee|unassigned at gcc dot gnu.org |msebor at gcc dot gnu.org
Keywords| |diagnostic
Last reconfirmed| |2021-10-25
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/102934] missing warning passing address of first member to free()
2021-10-25 17:19 [Bug middle-end/102934] New: missing warning passing address of first member to free() msebor at gcc dot gnu.org
2021-10-25 17:20 ` [Bug middle-end/102934] " msebor at gcc dot gnu.org
@ 2021-10-26 7:07 ` rguenth at gcc dot gnu.org
2022-01-26 17:19 ` msebor at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: rguenth at gcc dot gnu.org @ 2021-10-26 7:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102934
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
But the second is valid? p->a is just an obfuscated way to write p.
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug middle-end/102934] missing warning passing address of first member to free()
2021-10-25 17:19 [Bug middle-end/102934] New: missing warning passing address of first member to free() msebor at gcc dot gnu.org
2021-10-25 17:20 ` [Bug middle-end/102934] " msebor at gcc dot gnu.org
2021-10-26 7:07 ` rguenth at gcc dot gnu.org
@ 2022-01-26 17:19 ` msebor at gcc dot gnu.org
2 siblings, 0 replies; 4+ messages in thread
From: msebor at gcc dot gnu.org @ 2022-01-26 17:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102934
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|msebor at gcc dot gnu.org |unassigned at gcc dot gnu.org
Status|ASSIGNED |NEW
--- Comment #2 from Martin Sebor <msebor at gcc dot gnu.org> ---
I'm not working on this anymore.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-01-26 17:19 UTC | newest]
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2021-10-25 17:19 [Bug middle-end/102934] New: missing warning passing address of first member to free() msebor at gcc dot gnu.org
2021-10-25 17:20 ` [Bug middle-end/102934] " msebor at gcc dot gnu.org
2021-10-26 7:07 ` rguenth at gcc dot gnu.org
2022-01-26 17:19 ` msebor at gcc dot gnu.org
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