Date: Sat, 20 Jun 2015 03:23:03 +1000 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Dimitry Andric <dim@freebsd.org> Cc: Pedro Giffuni <pfg@freebsd.org>, David Chisnall <theraven@freebsd.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r268137 - head/sys/sys Message-ID: <20150620023835.N2562@besplex.bde.org> In-Reply-To: <D58BE060-870A-4D5E-AE46-D915D9CD6A0C@FreeBSD.org> References: <201407020845.s628jRG5031824@svn.freebsd.org> <5BE3492F-86A0-4CE3-A27C-8DB5EB662C64@FreeBSD.org> <55842F16.5040608@FreeBSD.org> <D58BE060-870A-4D5E-AE46-D915D9CD6A0C@FreeBSD.org>
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On Fri, 19 Jun 2015, Dimitry Andric wrote:
> On 19 Jun 2015, at 17:02, Pedro Giffuni <pfg@freebsd.org> wrote:
>>
>>> On 19/06/2015 05:16 a.m., David Chisnall wrote:
>>>> I only just caught this (having seen the fallout from NetBSD doing the=
same thing in a shipping release and the pain that it=E2=80=99s caused):
>>>>
>>>> __weak is a reserved keyword in Objective-C, please pick another name =
for this. This in cdefs.h makes it impossible to include any FreeBSD stand=
ard headers in Objective-C programs (of which we have a couple of hundred i=
n ports) if they use any of the modern Objective-C language modes.
> ...
>> Closely related to this, we are redefining _Noreturn, which is a reserve=
d keyword in C11.
>
> No, sys/cdefs.h has:
>
> 254 /*
> 255 * Keywords added in C11.
> 256 */
> 257
> 258 #if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L || de=
fined(lint)
> [...]
> 284 #if defined(__cplusplus) && __cplusplus >=3D 201103L
> 285 #define _Noreturn [[noreturn]]
> 286 #else
> 287 #define _Noreturn __dead2
> 288 #endif
> [...]
> 320 #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
>
> So the whole block redefining all the _Xxx identifiers is skipped for
> C11 and higher.
I probably pointed this out incorrectly to Pedro.
All uses of _Noreturn are still broken, and also ugly. __dead2 is the
gcc-2 compatible version of the gcc-1 compatible macro __dead. It is
syntactically different from __dead and _Noreturn. It must be placed
after the function parameter list instead of in the function type
declarator because old versions of gcc only accept attributes there.
__dead and presumably _Noreturn must be placed in the function type
declarator. This is incompatible, and also uglier.
> E.g.:
>
> $ cpp -std=3Dc99
> #include <sys/cdefs.h>
> _Noreturn void foo(void);
> ^D
> # 1 "<stdin>"
> # 1 "<built-in>" 1
> # 1 "<built-in>" 3
> # 306 "<built-in>" 3
> # 1 "<command line>" 1
> # 1 "<built-in>" 2
> # 1 "<stdin>" 2
> # 1 "/usr/include/sys/cdefs.h" 1 3 4
> # 2 "<stdin>" 2
> __attribute__((__noreturn__)) void foo(void);
Syntax error with older versions of gcc that cdefs.h is supposed to support=
=2E
Thee versions that don't support attributes in the declarator also don't
support c99, so the order can be anything with them, but this doesn't
simplify fixing the problem -- you still need massive ifdefs or ugly
declarations.
> $ cpp -std=3Dc11
> #include <sys/cdefs.h>
> _Noreturn void foo(void);
> ^D
> # 1 "<stdin>"
> # 1 "<built-in>" 1
> # 1 "<built-in>" 3
> # 306 "<built-in>" 3
> # 1 "<command line>" 1
> # 1 "<built-in>" 2
> # 1 "<stdin>" 2
> # 1 "/usr/include/sys/cdefs.h" 1 3 4
> # 2 "<stdin>" 2
> _Noreturn void foo(void);
Correct version with ugly declarations:
__dead void
=09foo(void) __dead2;
where:
1. __dead is the gcc-1 compatible macro restored to handle the different
spelling in C11. Direct spellings should not be used, since they cause
namespace bugs like the current ones for __weak.
2. __dead2 is the gcc-2 compatible macro. It also works for later gcc's
and clang, perhaps even in C11.
3. __dead is defined as follows:
a. for gcc-1, either leave it undefined (to keep its current behaviour
of breaking any use of it), or define as its gcc-1 value again.
b. for C11, define it as _Noreturn
c. otherwise, define it as empty
4. __dead2 is defined the same as now. Hopefully it is just redundant of
__dead is defined as _Noreturn for C11.
5. the style of the above is taken from 4.4BSD-Lite2, which still has __dea=
d
and still defines it as __volatile and still has almost no support for
gcc-2. From Lite2 stdlib.h:
__dead void
=09 abort __P((void));
=2E...
__dead void
=09 exit __P((int));
Putting __dead first messes up the formatting by requiring an extra line
to keep the function names lined up.
When I cleaned this up in FreeBSD, the first stage was to add __dead2 while
keeping __dead in 1994, the second stage was to remove __dead from
everywhere in the source tree except cdefs.h in 1996, and the "final" stage
was to remove the definition of __dead from cdefs.h in 1998. The current
breakage shows that this was not even the final stage.
Bruce
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From: "Simon J. Gerraty" <sjg@FreeBSD.org>
Date: Fri, 19 Jun 2015 17:35:00 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
svn-src-head@freebsd.org
Subject: svn commit: r284601 - head/sys/dev/filemon
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Author: sjg
Date: Fri Jun 19 17:34:59 2015
New Revision: 284601
URL: https://svnweb.freebsd.org/changeset/base/284601
Log:
sx_sunlock for sx_slock
Modified:
head/sys/dev/filemon/filemon_wrapper.c
Modified: head/sys/dev/filemon/filemon_wrapper.c
==============================================================================
--- head/sys/dev/filemon/filemon_wrapper.c Fri Jun 19 17:19:20 2015 (r284600)
+++ head/sys/dev/filemon/filemon_wrapper.c Fri Jun 19 17:34:59 2015 (r284601)
@@ -90,13 +90,13 @@ filemon_pid_check(struct proc *p)
while (p != initproc) {
TAILQ_FOREACH(filemon, &filemons_inuse, link) {
if (p->p_pid == filemon->pid) {
- sx_xunlock(&proctree_lock);
+ sx_sunlock(&proctree_lock);
return (filemon);
}
}
p = proc_realparent(p);
}
- sx_xunlock(&proctree_lock);
+ sx_sunlock(&proctree_lock);
return (NULL);
}
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