* Re: [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
[not found] ` <E1Y8CBN-0005MY-1J@vcs.savannah.gnu.org>
@ 2015-01-07 21:57 ` Herbert J. Skuhra
2015-01-08 2:10 ` Paul Eggert
2015-01-08 5:23 ` YAMAMOTO Mitsuharu
0 siblings, 2 replies; 5+ messages in thread
From: Herbert J. Skuhra @ 2015-01-07 21:57 UTC (permalink / raw
To: emacs-devel, Paul Eggert
Hi,
after this commit I can no longer build Emacs on Mac OS X (10.10.2):
Loading /Users/herbert/source/emacs/lisp/help.el (source)...
Loading /Users/herbert/source/emacs/lisp/jka-cmpr-hook.el (source)...
Loading /Users/herbert/source/emacs/lisp/epa-hook.el (source)...
Loading /Users/herbert/source/emacs/lisp/international/mule-cmds.el
(source)...
Loading /Users/herbert/source/emacs/lisp/case-table.el (source)...
Loading /Users/herbert/source/emacs/lisp/international/characters.el
(source)...
make[2]: *** [bootstrap-emacs] Illegal instruction: 4
make[1]: *** [src] Error 2
make: *** [bootstrap] Error 2
Building with Homebrew also fails.
58f2d6e does compile.
Sorry, if this a known issue!
--
Herbert
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
2015-01-07 21:57 ` [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil Herbert J. Skuhra
@ 2015-01-08 2:10 ` Paul Eggert
2015-01-08 2:29 ` Perry E. Metzger
2015-01-08 5:23 ` YAMAMOTO Mitsuharu
1 sibling, 1 reply; 5+ messages in thread
From: Paul Eggert @ 2015-01-08 2:10 UTC (permalink / raw
To: Herbert J. Skuhra, emacs-devel; +Cc: Perry E. Metzger
Herbert J. Skuhra wrote:
> Loading /Users/herbert/source/emacs/lisp/international/characters.el
> (source)...
> make[2]: *** [bootstrap-emacs] Illegal instruction: 4
Thanks, I reproduced the problem on FreeBSD 9 x86. Could you please try it with
the latest master (commit ad5ac01471b6795a5168b5e6fb7230adb08f3217)? That fixed
the problem for me.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
2015-01-08 2:10 ` Paul Eggert
@ 2015-01-08 2:29 ` Perry E. Metzger
0 siblings, 0 replies; 5+ messages in thread
From: Perry E. Metzger @ 2015-01-08 2:29 UTC (permalink / raw
To: Paul Eggert; +Cc: Herbert J. Skuhra, emacs-devel
On Wed, 07 Jan 2015 18:10:49 -0800 Paul Eggert <eggert@cs.ucla.edu>
wrote:
> Herbert J. Skuhra wrote:
>
> > Loading /Users/herbert/source/emacs/lisp/international/characters.el
> > (source)...
> > make[2]: *** [bootstrap-emacs] Illegal instruction: 4
>
> Thanks, I reproduced the problem on FreeBSD 9 x86. Could you
> please try it with the latest master (commit
> ad5ac01471b6795a5168b5e6fb7230adb08f3217)? That fixed the problem
> for me.
>
Build still fails for me on ad5ac01471b6795a5168b5e6fb7230adb08f3217
Loading /Users/perry/src/emacs/emacs/lisp/case-table.el (source)...
Loading /Users/perry/src/emacs/emacs/lisp/international/characters.el
(source)... make[1]: *** [bootstrap-emacs] Illegal instruction: 4
(core dumped) make: *** [src] Error 2
--
Perry E. Metzger perry@piermont.com
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
2015-01-07 21:57 ` [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil Herbert J. Skuhra
2015-01-08 2:10 ` Paul Eggert
@ 2015-01-08 5:23 ` YAMAMOTO Mitsuharu
2015-01-08 7:05 ` Paul Eggert
1 sibling, 1 reply; 5+ messages in thread
From: YAMAMOTO Mitsuharu @ 2015-01-08 5:23 UTC (permalink / raw
To: Herbert J. Skuhra; +Cc: Paul Eggert, emacs-devel
>>>>> On Wed, 7 Jan 2015 22:57:59 +0100, "Herbert J. Skuhra" <herbert@oslo.ath.cx> said:
> Hi,
> after this commit I can no longer build Emacs on Mac OS X (10.10.2):
> Loading /Users/herbert/source/emacs/lisp/help.el (source)...
> Loading /Users/herbert/source/emacs/lisp/jka-cmpr-hook.el (source)...
> Loading /Users/herbert/source/emacs/lisp/epa-hook.el (source)...
> Loading /Users/herbert/source/emacs/lisp/international/mule-cmds.el
> (source)...
> Loading /Users/herbert/source/emacs/lisp/case-table.el (source)...
> Loading /Users/herbert/source/emacs/lisp/international/characters.el
> (source)...
> make[2]: *** [bootstrap-emacs] Illegal instruction: 4
> make[1]: *** [src] Error 2
> make: *** [bootstrap] Error 2
> Building with Homebrew also fails.
> 58f2d6e does compile.
In src/lisp.h, we have:
# define lisp_h_XUNTAG(a, type) XUNTAGBASE (a, type, 0)
# define lisp_h_XUNTAGBASE(a, type, base) \
((void *) ((char *) (base) - (type) + (intptr_t) XLI (a)))
With the above macros, XUNTAG (a, type) is expanded to:
((void *) ((char *) (0) - (type) + (intptr_t) XLI (a)))
It is relative to the NULL pointer and clang seems to treat its
dereference as an undefined behavior. Reverting the definition of
lisp_h_XUNTAG to the previous version works for me.
# define lisp_h_XUNTAG(a, type) ((void *) (XLI (a) - (type)))
YAMAMOTO Mitsuharu
mituharu@math.s.chiba-u.ac.jp
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil
2015-01-08 5:23 ` YAMAMOTO Mitsuharu
@ 2015-01-08 7:05 ` Paul Eggert
0 siblings, 0 replies; 5+ messages in thread
From: Paul Eggert @ 2015-01-08 7:05 UTC (permalink / raw
To: YAMAMOTO Mitsuharu, Herbert J. Skuhra; +Cc: emacs-devel
[-- Attachment #1: Type: text/plain, Size: 492 bytes --]
YAMAMOTO Mitsuharu wrote:
> With the above macros, XUNTAG (a, type) is expanded to:
>
> ((void *) ((char *) (0) - (type) + (intptr_t) XLI (a)))
>
> It is relative to the NULL pointer and clang seems to treat its
> dereference as an undefined behavior.
Thanks for diagnosing that. This is arguably a bug in clang, but it's easy
enough to work around as you suggest. I reproduced the problem with Fedora 21
x86-64 (clang 3.5.0) and installed the attached patch, which fixed it for me.
[-- Attachment #2: 0001-Port-Qnil-0-XUNTAG-to-clang.patch --]
[-- Type: text/x-patch, Size: 2082 bytes --]
From 8d025fa15493be4079d05629e9ca8b7ae325fc58 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 7 Jan 2015 23:02:01 -0800
Subject: [PATCH] Port Qnil==0 XUNTAG to clang
clang has undefined behavior if the program subtracts an integer
from (char *) 0. Problem reported by YAMAMOTO Mitsuharu in:
http://lists.gnu.org/archive/html/emacs-devel/2015-01/msg00132.html
* lisp.h (lisp_h_XUNTAG) [USE_LSB_TAG]:
(XUNTAG) [!USE_LSB_TAG]: Port to clang 3.5.0.
---
src/ChangeLog | 7 +++++++
src/lisp.h | 5 +++--
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index eae16c2..817483b 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,12 @@
2015-01-08 Paul Eggert <eggert@cs.ucla.edu>
+ Port Qnil==0 XUNTAG to clang
+ clang has undefined behavior if the program subtracts an integer
+ from (char *) 0. Problem reported by YAMAMOTO Mitsuharu in:
+ http://lists.gnu.org/archive/html/emacs-devel/2015-01/msg00132.html
+ * lisp.h (lisp_h_XUNTAG) [USE_LSB_TAG]:
+ (XUNTAG) [!USE_LSB_TAG]: Port to clang 3.5.0.
+
Port GFileMonitor * hack to Qnil==0 platforms
Reported by Glenn Morris in: http://bugs.gnu.org/15880#112
* gfilenotify.c (monitor_to_lisp, lisp_to_monitor): New functions.
diff --git a/src/lisp.h b/src/lisp.h
index 1f18b5e..b9263f8 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -368,7 +368,7 @@ error !;
# define lisp_h_XFASTINT(a) XINT (a)
# define lisp_h_XINT(a) (XLI (a) >> INTTYPEBITS)
# define lisp_h_XTYPE(a) ((enum Lisp_Type) (XLI (a) & ~VALMASK))
-# define lisp_h_XUNTAG(a, type) XUNTAGBASE (a, type, 0)
+# define lisp_h_XUNTAG(a, type) ((void *) (intptr_t) (XLI (a) - (type)))
# define lisp_h_XUNTAGBASE(a, type, base) \
((void *) ((char *) (base) - (type) + (intptr_t) XLI (a)))
#endif
@@ -905,7 +905,8 @@ XUNTAGBASE (Lisp_Object a, int type, void *base)
INLINE void *
XUNTAG (Lisp_Object a, int type)
{
- return XUNTAGBASE (a, type, 0);
+ intptr_t i = USE_LSB_TAG ? XLI (a) - type : XLI (a) & VALMASK;
+ return (void *) i;
}
#endif /* ! USE_LSB_TAG */
--
2.1.0
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[not found] <20150105181510.19723.18782@vcs.savannah.gnu.org>
[not found] ` <E1Y8CBN-0005MY-1J@vcs.savannah.gnu.org>
2015-01-07 21:57 ` [Emacs-diffs] master bc78ff2 2/2: Use 0 for Qnil Herbert J. Skuhra
2015-01-08 2:10 ` Paul Eggert
2015-01-08 2:29 ` Perry E. Metzger
2015-01-08 5:23 ` YAMAMOTO Mitsuharu
2015-01-08 7:05 ` Paul Eggert
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