Re: ICU / NSDateFormatter crash

[Riccardo Mottola]

Hi,

David Chisnall wrote:
> This is quite surprising.  On FreeBSD, this function should be provided by 
> libcxxrt, not libsupc++.  Please file a bug report with the FreeBSD gcc 
> maintainer - it looks as if you’ve somehow ended up with a program linking both 
> libc++ from base and libstdc++ from ports, and the libstdc++ from ports is 
> incorrectly using its own internal libsupc++ instead of the system-provided 
> libcxxrt (which I wrote, so can help debugging a bit better).
>
> That said, this function should not crash.  It should only do so if the object 
> that is being passed to it is invalid.  Is  0x2e904a80 a valid address of an 
> icu::UObject?

how can I know?

> The crash calling a null function pointer looks a bit suspicious, because the 
> only function pointers invoked by this function should be from the typeinfo 
> object’s vtable, and should never be null.  There was an ABI break for the 
> layout of typeinfo vtables from gcc a while ago and I don’t remember which one 
> FreeBSD ended up with, but if you’re linking both libcxxrt and libsupc++ then 
> you may end up with this.

that's unfortunate. It took me a while to respond, because I notived a 
minor update in the GCC 5 package and updated to it (I do through 
compilation on my own using portupgrade). I also updated other things.

#0  0x00000000 in ?? ()
#1  0x29c0ad42 in __cxxabiv1::__dynamic_cast (src_ptr=0x2e904a80,
    src_type=0x2973c618 <typeinfo for icu::UObject>,
    dst_type=0x2973d8b8 <typeinfo for icu::UnicodeString>, src2dst=0)
    at 
/usr/ports/lang/gcc5/work/gcc-5.4.0/libstdc++-v3/libsupc++/dyncast.cc:72
#2  0x2942d51d in icu::Calendar::makeInstance(icu::Locale const&, 
UErrorCode&)
    () from /usr/local/lib/libicui18n.so.58
#3  0x2942d3ba in 
icu::LocaleCacheKey<icu::SharedCalendar>::createObject(void const*, 
UErrorCode&) const () from /usr/local/lib/libicui18n.so.58
#4  0x296d190f in icu::UnifiedCache::_get(icu::CacheKeyBase const&, 
icu::SharedObject const*&, void const*, UErrorCode&) const ()
   from /usr/local/lib/libicuuc.so.58
#5  0x29438906 in void 
icu::UnifiedCache::get<icu::SharedCalendar>(icu::CacheKey<icu::SharedCalendar> 
const&, void const*, icu::SharedCalendar const*&, UErrorCode&) const () 
from /usr/local/lib/libicui18n.so.58
#6  0x29437d78 in void 
icu::UnifiedCache::getByLocale<icu::SharedCalendar>(icu::Locale const&, 
icu::SharedCalendar const*&, UErrorCode&) ()
   from /usr/local/lib/libicui18n.so.58
#7  0x2942e90d in icu::Calendar::createInstance(icu::TimeZone*, 
icu::Locale const&, UErrorCode&) () from /usr/local/lib/libicui18n.so.58
#8  0x293ec0f1 in 
icu::SimpleDateFormat::construct(icu::DateFormat::EStyle, 
icu::DateFormat::EStyle, icu::Locale const&, UErrorCode&) ()
   from /usr/local/lib/libicui18n.so.58


Thre crash is still in place and it is still using libsupc++

Do you want more information of the stacktrace or should I just file a 
bug right away?
This is a box running 10.3 and gcc5 is still "standard gcc from ports" 
as far as I know. I did try gcc6 a couple of months ago but it was non 
functional to compile gnustep... it was a mess, while gcc5 just worked 
fine (.except this issue, which I did not have a couple of months ago, 
but I don't know exactly what broke it)

It could be April 1 commit by gerald :)

Riccardo