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* [Bug middle-end/94208] New: missing warning on passing unterminated local array to string functions
@ 2020-03-17 22:21 msebor at gcc dot gnu.org
2024-04-07 5:25 ` [Bug middle-end/94208] " pinskia at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: msebor at gcc dot gnu.org @ 2020-03-17 22:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94208
Bug ID: 94208
Summary: missing warning on passing unterminated local array to
string functions
Product: gcc
Version: 10.0
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 10 diagnoses only one out of the three invalid uses of the unterminated
array below. The strlen pass "knows" the number of non-zero characters in each
of the local arrays and it also knows it's equal to the size of the array so it
has all it needs to diagnose the calls.
The problem is the same with other string functions (e.g., strlen or sprintf)
so a complete fix should extend the warning to all of them.
$ cat t.c && gcc -O2 -S -Wall -Wextra -Wpedantic
-fdump-tree-optimized=/dev/stdout t.c
const char a[4] = { '1', '2', '3', '4' };
void f0 (char *d)
{
__builtin_strcpy (d, a); // warning (good)
}
void f1 (char *d)
{
const char a[4] = { '1', '2', '3', '4' };
__builtin_strcpy (d, a); // missing warning
}
void f2 (char *d)
{
__builtin_strcpy (d, (char[4]){ '1', '2', '3', '4' }); // missing warning
}
t.c: In function ‘f0’:
t.c:5:3: warning: ‘strcpy’ argument missing terminating nul
[-Wstringop-overflow=]
5 | __builtin_strcpy (d, a); // warning (good)
| ^~~~~~~~~~~~~~~~~~~~~~~
t.c:1:12: note: referenced argument declared here
1 | const char a[4] = { '1', '2', '3', '4' };
| ^
;; Function f0 (f0, funcdef_no=0, decl_uid=1931, cgraph_uid=1, symbol_order=1)
f0 (char * d)
{
<bb 2> [local count: 1073741824]:
__builtin_strcpy (d_2(D), &a); [tail call]
return;
}
;; Function f1 (f1, funcdef_no=1, decl_uid=1934, cgraph_uid=2, symbol_order=2)
f1 (char * d)
{
const char a[4];
<bb 2> [local count: 1073741824]:
a = "1234";
__builtin_strcpy (d_3(D), &a);
a ={v} {CLOBBER};
return;
}
;; Function f2 (f2, funcdef_no=2, decl_uid=1938, cgraph_uid=3, symbol_order=3)
f2 (char * d)
{
char D.1940[4];
<bb 2> [local count: 1073741824]:
MEM <unsigned int> [(char *)&D.1940] = 875770417;
__builtin_strcpy (d_6(D), &D.1940);
D.1940 ={v} {CLOBBER};
return;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug middle-end/94208] missing warning on passing unterminated local array to string functions
2020-03-17 22:21 [Bug middle-end/94208] New: missing warning on passing unterminated local array to string functions msebor at gcc dot gnu.org
@ 2024-04-07 5:25 ` pinskia at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: pinskia at gcc dot gnu.org @ 2024-04-07 5:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94208
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2024-04-07
Status|UNCONFIRMED |NEW
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-03-17 22:21 [Bug middle-end/94208] New: missing warning on passing unterminated local array to string functions msebor at gcc dot gnu.org
2024-04-07 5:25 ` [Bug middle-end/94208] " pinskia at gcc dot gnu.org
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