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* [Bug tree-optimization/96826] New: missing warning appending to the result of strdup
@ 2020-08-27 22:06 msebor at gcc dot gnu.org
2020-08-27 22:07 ` [Bug tree-optimization/96826] " msebor at gcc dot gnu.org
0 siblings, 1 reply; 2+ messages in thread
From: msebor at gcc dot gnu.org @ 2020-08-27 22:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96826
Bug ID: 96826
Summary: missing warning appending to the result of strdup
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: msebor at gcc dot gnu.org
Target Milestone: ---
Appending to a string created by strdup is not diagnosed by could be by looking
up the origin of the destination pointer and, if it's used in a call to a
function like strcat, or if it's accessed at an offset derived from strlen of
either the copy or the original (with no subtraction), issuing
-Wstringop-overflow.
$ cat z.c && /build/gcc-master/gcc/xgcc -B /build/gcc-master/gcc -O2 -S -Wall
z.c
void* f0 (const char *s)
{
char *t = __builtin_strdup (s);
__builtin_strcat (t, "xyz"); // missing warning
return t;
}
void* f1 (const char *s)
{
char *t = __builtin_strdup (s);
t += __builtin_strlen (t);
t[0] = 'x';
t[1] = 'y'; // missing warning
t[2] = 'z'; // ditto
return t;
}
void* f2 (const char *s)
{
char *t = __builtin_strdup (s);
t += __builtin_strlen (t);
__builtin_sprintf (t, "%i", 123); // missing warning
return t;
}
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug tree-optimization/96826] missing warning appending to the result of strdup
2020-08-27 22:06 [Bug tree-optimization/96826] New: missing warning appending to the result of strdup msebor at gcc dot gnu.org
@ 2020-08-27 22:07 ` msebor at gcc dot gnu.org
0 siblings, 0 replies; 2+ messages in thread
From: msebor at gcc dot gnu.org @ 2020-08-27 22:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96826
Martin Sebor <msebor at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |83819
Keywords| |diagnostic
Severity|normal |enhancement
--- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> ---
Since it tracks all these calls the strlen pass is probably the most suitable
place to implement the warning.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83819
[Bug 83819] [meta-bug] missing strlen optimizations
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-08-27 22:06 [Bug tree-optimization/96826] New: missing warning appending to the result of strdup msebor at gcc dot gnu.org
2020-08-27 22:07 ` [Bug tree-optimization/96826] " msebor at gcc dot gnu.org
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