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| author | Paul Eggert <eggert@cs.ucla.edu> | 2015-01-07 23:02:01 -0800 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2015-01-07 23:02:27 -0800 |
| commit | f6a27d26dccdcc121bebc96fbf41f656fbf13138 (patch) | |
| tree | 344d746bc2738cbf6a19bc378236b3a6810febc2 /src | |
| parent | 9f654763f2223ce9f3317b44a3d1a8ac2c8bb832 (diff) | |
| download | emacs-f6a27d26dccdcc121bebc96fbf41f656fbf13138.tar.gz | |
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.
Diffstat (limited to 'src')
| -rw-r--r-- | src/ChangeLog | 7 | ||||
| -rw-r--r-- | src/lisp.h | 5 |
2 files changed, 10 insertions, 2 deletions
diff --git a/src/ChangeLog b/src/ChangeLog index eae16c27b75..817483be1fb 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 1f18b5e0775..b9263f88c11 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 */ |