* 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 ^ permalink raw reply related [flat|nested] 5+ messages in thread
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[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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