Re: [tz] [C/C++ PATCH] Implement -Wshift-negative-value (PR c/65179)
On 05/08/2015 09:59 AM, Joseph Myers wrote:
Paul, although glibc's copy of parts of tzcode is a bit out of date, it looks like the currenthttps://github.com/eggert/tz.git still has the problematic code in private.h, relying on left-shifting -1 which has undefined behavior in C99/C11 (implementation-defined in C90, as per DR#081). Thanks for reporting that. I installed the attached patch into the experimental tz version on github <https://github.com/eggert/tz>, with the intent that this fix propagate into the next tz release and thus into glibc etc.
On Fri, 2015-05-08 at 14:54 -0700, Paul Eggert wrote:
On 05/08/2015 09:59 AM, Joseph Myers wrote:
Paul, although glibc's copy of parts of tzcode is a bit out of date, it looks like the currenthttps://github.com/eggert/tz.git still has the problematic code in private.h, relying on left-shifting -1 which has undefined behavior in C99/C11 (implementation-defined in C90, as per DR#081). Thanks for reporting that. I installed the attached patch into the experimental tz version on github <https://github.com/eggert/tz>, with the intent that this fix propagate into the next tz release and thus into glibc etc.
FYI: I put this into my glibc sources (the private.h, zdump.c, and zic.c parts, glibc doesn't have localtime.c in the timezone directory and the one in the time directory doesn't look like it matches what was patched). And my GCC/glibc toolchain now builds. I didn't run the glibc testsuite but I ran the GCC testsuite using this patch and everything looked fine. Steve Ellcey sellcey@imgtec.com
On May 11, 3:18pm, sellcey@imgtec.com (Steve Ellcey) wrote: -- Subject: Re: [tz] [C/C++ PATCH] Implement -Wshift-negative-value (PR c/651 | FYI: I put this into my glibc sources (the private.h, zdump.c, and zic.c | parts, glibc doesn't have localtime.c in the timezone directory and the | one in the time directory doesn't look like it matches what was | patched). And my GCC/glibc toolchain now builds. I didn't run the | glibc testsuite but I ran the GCC testsuite using this patch and | everything looked fine. If you want it to work exactly like glibc as a drop in replacement, you need to copy the NO_ERROR_IN_DST_GAP code from: http://nxr.netbsd.org/xref/src/lib/libc/time/localtime.c christos
participants (3)
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christos＠zoulas.com -
Paul Eggert -
Steve Ellcey