[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Martin Sebor changed: What|Removed |Added Known to work||10.1.0 Status|ASSIGNED|RESOLVED Blocks||95507 Resolution|--- |FIXED Target Milestone|--- |10.2 --- Comment #9 from Martin Sebor --- Fixed in GCC 10. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95507 [Bug 95507] [meta-bug] bogus/missing -Wnonnull
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 --- Comment #8 from Martin Sebor --- Author: msebor Date: Wed Oct 2 22:00:42 2019 New Revision: 276491 URL: https://gcc.gnu.org/viewcvs?rev=276491=gcc=rev Log: PR tree-optimization/80936 - bcmp, bcopy, and bzero not declared nonnull gcc/testsuite/ChangeLog: PR tree-optimization/80936 * gcc.dg/Wnonnull-2.c: New test. * gcc.dg/Wnonnull-3.c: New test. * gcc.dg/nonnull-3.c: Expect more warnings. gcc/ChangeLog: PR tree-optimization/80936 * builtins.def (bcmp, bcopy, bzero): Declare nonnull. Added: trunk/gcc/testsuite/gcc.dg/Wnonnull-2.c trunk/gcc/testsuite/gcc.dg/Wnonnull-3.c Modified: trunk/gcc/builtins.def trunk/gcc/testsuite/gcc.dg/nonnull-3.c
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Martin Sebor changed: What|Removed |Added Keywords||patch --- Comment #7 from Martin Sebor --- Patch: https://gcc.gnu.org/ml/gcc-patches/2019-09/msg01620.html
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Martin Sebor changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |msebor at gcc dot gnu.org --- Comment #6 from Martin Sebor --- Testing a patch.
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936
--- Comment #5 from Eric Gallager ---
(In reply to Martin Sebor from comment #4)
> POSIX says this about bcopy:
>
> For maximum portability, it is recommended to replace the function call to
> bcopy() as follows:
>
> #define bcopy(b1,b2,len) (memmove((b2), (b1), (len)), (void) 0)
>
> GCC lowers bcopy calls to memmove (and similarly for other bxxx calls),
> which I think makes it even more important that the non-null attribute be
> applied to their declarations, to detect bugs due to legacy code making the
> assumption that bcopy et al are null-safe (e.g., on a target where they
> really are).
>
> $ cat t.c && gcc -O0 -S -Wall -fdump-tree-lower=/dev/stdout t.c
> void f (void *d, const void *s, __SIZE_TYPE__ n)
> {
> __builtin_bcopy (s, 0, n);
> }
>
> ;; Function f (f, funcdef_no=0, decl_uid=1908, cgraph_uid=1, symbol_order=0)
>
> f (void * d, const void * s, long unsigned int n)
> {
> __builtin_memmove (0B, s, n);
> return;
> }
ok, be sure to update the comment, then, once you add the attribute
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936
Martin Sebor changed:
What|Removed |Added
Status|RESOLVED|NEW
Resolution|INVALID |---
Known to fail||7.3.0, 8.2.0, 9.0
--- Comment #4 from Martin Sebor ---
POSIX says this about bcopy:
For maximum portability, it is recommended to replace the function call to
bcopy() as follows:
#define bcopy(b1,b2,len) (memmove((b2), (b1), (len)), (void) 0)
GCC lowers bcopy calls to memmove (and similarly for other bxxx calls), which I
think makes it even more important that the non-null attribute be applied to
their declarations, to detect bugs due to legacy code making the assumption
that bcopy et al are null-safe (e.g., on a target where they really are).
$ cat t.c && gcc -O0 -S -Wall -fdump-tree-lower=/dev/stdout t.c
void f (void *d, const void *s, __SIZE_TYPE__ n)
{
__builtin_bcopy (s, 0, n);
}
;; Function f (f, funcdef_no=0, decl_uid=1908, cgraph_uid=1, symbol_order=0)
f (void * d, const void * s, long unsigned int n)
{
__builtin_memmove (0B, s, n);
return;
}
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Eric Gallager changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |INVALID --- Comment #3 from Eric Gallager --- (In reply to Eric Gallager from comment #2) > Comment in builtins.def says: > > /* bcmp, bcopy and bzero have traditionally accepted NULL pointers >when the length parameter is zero, so don't apply attribute "nonnull". */ > > svn blame says Kaveh Ghazi wrote that comment; cc-ing him I'm thinking that this comment means that the current behavior is intentional, in which case there's no bug here.
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Eric Gallager changed: What|Removed |Added CC||ghazi at gcc dot gnu.org --- Comment #2 from Eric Gallager --- Comment in builtins.def says: /* bcmp, bcopy and bzero have traditionally accepted NULL pointers when the length parameter is zero, so don't apply attribute "nonnull". */ svn blame says Kaveh Ghazi wrote that comment; cc-ing him
[Bug tree-optimization/80936] bcmp, bcopy, and bzero not declared nonnull
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80936 Eric Gallager changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2017-08-29 CC||egallager at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Eric Gallager --- I get warnings for the bcopy parts: $ /usr/local/bin/gcc -c -O2 -S -Wall -Wextra 80936.c 80936.c: In function ‘zero0’: 80936.c:4:3: warning: argument 1 null where non-null expected [-Wnonnull] __builtin_memset (p, 0, n); // warning, good ^~ 80936.c:4:3: note: in a call to built-in function ‘__builtin_memset’ 80936.c: In function ‘copy0’: 80936.c:16:3: warning: argument 1 null where non-null expected [-Wnonnull] __builtin_memcpy (p, q, n); // warning, good ^~ 80936.c:16:3: note: in a call to built-in function ‘__builtin_memcpy’ 80936.c: In function ‘copy1’: 80936.c:22:3: warning: argument 2 null where non-null expected [-Wnonnull] __builtin_memcpy (p, q, n); // warning, good ^~ 80936.c:22:3: note: in a call to built-in function ‘__builtin_memcpy’ 80936.c: In function ‘copy2’: 80936.c:28:3: warning: argument 1 null where non-null expected [-Wnonnull] __builtin_bcopy (q, p, n); // missing warning ^ 80936.c:28:3: note: in a call to built-in function ‘__builtin_memmove’ 80936.c: In function ‘copy3’: 80936.c:34:3: warning: argument 2 null where non-null expected [-Wnonnull] __builtin_bcopy (q, p, n); // missing warning ^ 80936.c:34:3: note: in a call to built-in function ‘__builtin_memmove’ 80936.c: In function ‘cmp0’: 80936.c:40:10: warning: argument 1 null where non-null expected [-Wnonnull] return __builtin_memcmp (p, q, n); // warning, good ^~ 80936.c:40:10: note: in a call to built-in function ‘__builtin_memcmp’ 80936.c: In function ‘cmp1’: 80936.c:47:10: warning: argument 2 null where non-null expected [-Wnonnull] return __builtin_memcmp (p, q, n); // warning, good ^~ 80936.c:47:10: note: in a call to built-in function ‘__builtin_memcmp’ $ Confirmed for the rest though.
