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* [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null
@ 2005-01-20  9:52 marcus at jet dot franken dot de
  2005-01-20  9:53 ` [Bug c++/19542] " marcus at jet dot franken dot de
                   ` (9 more replies)
  0 siblings, 10 replies; 11+ messages in thread
From: marcus at jet dot franken dot de @ 2005-01-20  9:52 UTC (permalink / raw)
  To: gcc-bugs

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain, Size: 819 bytes --]

when using __attribute__((__sentinel__)) with the C++ NULL defined 
as __null, a sentinel warning is still triggered. 
 
Attached testcase gives: 
 
g++ -c xx.cc -Wall 
xx.cc: In function ‘void g()’: 
xx.cc:5: warning: missing sentinel in function call

-- 
           Summary: attribute(sentinel) has problems with C++ __null
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: marcus at jet dot franken dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
@ 2005-01-20  9:53 ` marcus at jet dot franken dot de
  2005-01-20 13:11 ` giovannibajo at libero dot it
                   ` (8 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: marcus at jet dot franken dot de @ 2005-01-20  9:53 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From marcus at jet dot franken dot de  2005-01-20 09:52 -------
Created an attachment (id=8003)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=8003&action=view)
xx.cc

testcse, compile with -Wall

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
  2005-01-20  9:53 ` [Bug c++/19542] " marcus at jet dot franken dot de
@ 2005-01-20 13:11 ` giovannibajo at libero dot it
  2005-01-20 13:44 ` marcus at jet dot franken dot de
                   ` (7 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: giovannibajo at libero dot it @ 2005-01-20 13:11 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From giovannibajo at libero dot it  2005-01-20 13:11 -------
__null is 0 of integer type, while attribute sentinel checks for 0 of pointer 
type. Remember this is not the same because it depends on the ABI: on some 
platforms, pushing a 0 of integer type into the stack for a call is different 
from pushing a 0 of pointer type. In fact, using __null for (eg) concat() is 
actually a real bug.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
  2005-01-20  9:53 ` [Bug c++/19542] " marcus at jet dot franken dot de
  2005-01-20 13:11 ` giovannibajo at libero dot it
@ 2005-01-20 13:44 ` marcus at jet dot franken dot de
  2005-01-20 15:00 ` pinskia at gcc dot gnu dot org
                   ` (6 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: marcus at jet dot franken dot de @ 2005-01-20 13:44 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From marcus at jet dot franken dot de  2005-01-20 13:44 -------
well, i am not specifying the NULL, the code actually has "NULL". 
 
However it gets defined by the gcc stdef.h file: 
 
#if defined (_STDDEF_H) || defined (__need_NULL) 
#undef NULL             /* in case <stdio.h> has defined it. */ 
#ifdef __GNUG__ 
#define NULL __null 
#else   /* G++ */ 
#ifndef __cplusplus 
#define NULL ((void *)0) 
#else   /* C++ */ 
#define NULL 0 
#endif  /* C++ */ 
#endif  /* G++ */ 
#endif  /* NULL not defined and <stddef.h> or need NULL.  */ 
#undef  __need_NULL 
 
 
So: 
- is gcc wrong? 
- should the code always use (type*)NULL  in such vararg lists? 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (2 preceding siblings ...)
  2005-01-20 13:44 ` marcus at jet dot franken dot de
@ 2005-01-20 15:00 ` pinskia at gcc dot gnu dot org
  2005-01-20 15:05 ` marcus at jet dot franken dot de
                   ` (5 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-01-20 15:00 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2005-01-20 15:00 -------
C++ is differrent from C.
NULL in C++ is defined special in that it is defined as an int but C is different.  You should always use a 
cast when you passing to a varargs otherwise you might get a problem on 64bit targets and otherwise.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (3 preceding siblings ...)
  2005-01-20 15:00 ` pinskia at gcc dot gnu dot org
@ 2005-01-20 15:05 ` marcus at jet dot franken dot de
  2005-01-20 15:35 ` matz at suse dot de
                   ` (4 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: marcus at jet dot franken dot de @ 2005-01-20 15:05 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From marcus at jet dot franken dot de  2005-01-20 15:05 -------
thanks! 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (4 preceding siblings ...)
  2005-01-20 15:05 ` marcus at jet dot franken dot de
@ 2005-01-20 15:35 ` matz at suse dot de
  2005-05-01  1:13 ` cvs-commit at gcc dot gnu dot org
                   ` (3 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: matz at suse dot de @ 2005-01-20 15:35 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From matz at suse dot de  2005-01-20 15:35 -------
I agree that C++ is special, and that NULL in C++ is only a null pointer 
constant (but not a null pointer).  Hence, yes, strictly speaking a cast 
would be needed even for NULL in va_lists. 
 
But, as a matter of fact, GCC defines __null as an integer node having value 
zero, and type exactly as wide as a pointer would be (i.e. somewhat 
similar to 0L).  So, giving this to a va_list, which expects a pointer 
would work correctly, also on LP64 platforms.  This is the reason for the 
existance of __null (as otherwise we could simply define NULL to "0" and 
still be completely standard conformant).  This suggests that those 
who implemented __null did it because they wanted to enable its use 
in situations where in C a lonely "NULL" is enough. 
 
As a QOI issue it would be better if this warning wouldn't trigger for this 
use.  In our packages it triggers quite often in C++ code, most of them 
being false positives.  That's in difference to C, where most of these 
warnings indeed are problems for LP64 platforms. 
 
I believe (but haven't verified) that the warning could additionally check 
for the node being == null_node, and not warn in this case.  This wouldn't 
make the warning less usefull AFAICS, and for C++ would reduce the number 
of false positives. 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (5 preceding siblings ...)
  2005-01-20 15:35 ` matz at suse dot de
@ 2005-05-01  1:13 ` cvs-commit at gcc dot gnu dot org
  2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
                   ` (2 subsequent siblings)
  9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2005-05-01  1:13 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-05-01 01:13 -------
Subject: Bug 19542

CVSROOT:	/cvs/gcc
Module name:	gcc
Branch: 	gcc-4_0-branch
Changes by:	matz@gcc.gnu.org	2005-05-01 01:13:09

Modified files:
	gcc            : c-common.h c-opts.c c.opt c-common.c ChangeLog 
	gcc/doc        : invoke.texi 
	gcc/cp         : cp-tree.h lex.c ChangeLog 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/warn: sentinel.C 

Log message:
	ChangeLog:
	PR c++/19542
	* c-common.c (c_common_nodes_and_builtins): Create global null_node.
	(warn_strict_null_sentinel): Define.
	(check_function_sentinel): Check for null_node as valid sentinel too.
	* c-common.h (c_tree_index): Added CTI_NULL.
	(null_node) Define global_tree[CTI_NULL].
	(warn_strict_null_sentinel): Declare.
	* c-opts.c: (c_common_handle_option): Handle -Wstrict-null-sentinel.
	* c.opt: (Wstrict-null-sentinel): New C++ option.
	* doc/invoke.texi (C++ Options): Document -Wstrict-null-sentinel.
	
	cp/ChangeLog:
	PR c++/19542
	* cp-tree.h (cp_tree_index): Remove CPTI_NULL, to be defined in C
	common frontend.
	(null_node): Remove.
	* lex.c (cxx_init): Move null_node initialisation to C common frontend.
	
	testsuite/ChangeLog:
	PR c++/19542
	* g++.dg/warn/sentinel.C: New testcase for __null sentinels added.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-common.h.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.277.2.1&r2=1.277.2.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-opts.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.136.2.2&r2=1.136.2.3
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c.opt.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.34.8.3&r2=1.34.8.4
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-common.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.606.2.2&r2=1.606.2.3
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=2.7592.2.207&r2=2.7592.2.208
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/doc/invoke.texi.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.583.2.15&r2=1.583.2.16
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/cp-tree.h.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.1106.2.3&r2=1.1106.2.4
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/lex.c.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.353&r2=1.353.12.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.4648.2.36&r2=1.4648.2.37
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/warn/sentinel.C.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=NONE&r2=1.1.2.1
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&only_with_tag=gcc-4_0-branch&r1=1.5084.2.151&r2=1.5084.2.152



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (7 preceding siblings ...)
  2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
@ 2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
  2005-05-02  4:23 ` cvs-commit at gcc dot gnu dot org
  9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-05-01  3:39 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-01 03:39 -------
Reopening to ..

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |UNCONFIRMED
         Resolution|INVALID                     |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (6 preceding siblings ...)
  2005-05-01  1:13 ` cvs-commit at gcc dot gnu dot org
@ 2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
  2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
  2005-05-02  4:23 ` cvs-commit at gcc dot gnu dot org
  9 siblings, 0 replies; 11+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2005-05-01  3:39 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-01 03:39 -------
To Mark as a dup of bug 18886.

*** This bug has been marked as a duplicate of 18886 ***

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
* [Bug c++/19542] attribute(sentinel) has problems with C++ __null
  2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
                   ` (8 preceding siblings ...)
  2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
@ 2005-05-02  4:23 ` cvs-commit at gcc dot gnu dot org
  9 siblings, 0 replies; 11+ messages in thread
From: cvs-commit at gcc dot gnu dot org @ 2005-05-02  4:23 UTC (permalink / raw)
  To: gcc-bugs


------- Additional Comments From cvs-commit at gcc dot gnu dot org  2005-05-02 04:23 -------
Subject: Bug 19542

CVSROOT:	/cvs/gcc
Module name:	gcc
Changes by:	matz@gcc.gnu.org	2005-05-02 04:22:57

Modified files:
	gcc            : c-common.c c-common.h c-opts.c c.opt ChangeLog 
	gcc/doc        : invoke.texi 
	gcc/cp         : cp-tree.h lex.c ChangeLog 
	gcc/testsuite  : ChangeLog 
Added files:
	gcc/testsuite/g++.dg/warn: sentinel.C 

Log message:
	PR c++/19542
	* c-common.c (c_common_nodes_and_builtins): Create global null_node.
	(warn_strict_null_sentinel): Define.
	(check_function_sentinel): Check for null_node as valid sentinel too.
	* c-common.h (c_tree_index): Added CTI_NULL.
	(null_node) Define global_tree[CTI_NULL].
	(warn_strict_null_sentinel): Declare.
	* c-opts.c: (c_common_handle_option): Handle -Wstrict-null-sentinel.
	* c.opt: (Wstrict-null-sentinel): New C++ option.
	* doc/invoke.texi (C++ Options): Document -Wstrict-null-sentinel.
	
	* cp-tree.h (cp_tree_index): Remove CPTI_NULL, to be defined in C
	common frontend.
	(null_node): Remove.
	* lex.c (cxx_init): Move null_node initialisation to C common frontend.
	
	* g++.dg/warn/sentinel.C: New testcase for __null sentinels added.

Patches:
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-common.c.diff?cvsroot=gcc&r1=1.625&r2=1.626
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-common.h.diff?cvsroot=gcc&r1=1.288&r2=1.289
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c-opts.c.diff?cvsroot=gcc&r1=1.142&r2=1.143
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/c.opt.diff?cvsroot=gcc&r1=1.41&r2=1.42
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/ChangeLog.diff?cvsroot=gcc&r1=2.8553&r2=2.8554
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/doc/invoke.texi.diff?cvsroot=gcc&r1=1.610&r2=1.611
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/cp-tree.h.diff?cvsroot=gcc&r1=1.1131&r2=1.1132
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/lex.c.diff?cvsroot=gcc&r1=1.355&r2=1.356
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/cp/ChangeLog.diff?cvsroot=gcc&r1=1.4724&r2=1.4725
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/g++.dg/warn/sentinel.C.diff?cvsroot=gcc&r1=1.1&r2=1.2
http://gcc.gnu.org/cgi-bin/cvsweb.cgi/gcc/gcc/testsuite/ChangeLog.diff?cvsroot=gcc&r1=1.5423&r2=1.5424



-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19542


^ permalink raw reply	[flat|nested] 11+ messages in thread
end of thread, other threads:[~2005-05-02  4:23 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2005-01-20  9:52 [Bug c++/19542] New: attribute(sentinel) has problems with C++ __null marcus at jet dot franken dot de
2005-01-20  9:53 ` [Bug c++/19542] " marcus at jet dot franken dot de
2005-01-20 13:11 ` giovannibajo at libero dot it
2005-01-20 13:44 ` marcus at jet dot franken dot de
2005-01-20 15:00 ` pinskia at gcc dot gnu dot org
2005-01-20 15:05 ` marcus at jet dot franken dot de
2005-01-20 15:35 ` matz at suse dot de
2005-05-01  1:13 ` cvs-commit at gcc dot gnu dot org
2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
2005-05-01  3:39 ` pinskia at gcc dot gnu dot org
2005-05-02  4:23 ` cvs-commit at gcc dot gnu dot org

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