That's strange indeed. But we've had problem with certain gcc optimizations before, https://trac.pjsip.org/repos/ticket/23, and just as this one we also don't know what's going on. Can you avoid the problem using a lighter expression than printf? Say, with PJ_UNUSED_ARG(tmp_hdr.name.ptr). Best regards, ?Benny On Thu, Dec 16, 2010 at 5:13 PM, <s.marek at avm.de> wrote: > Hello, > > there's a strange issue with PJSIP 1.8.10 on iOS. XCodes default > optimization level for Release builds is -Os. When compiled this way, > PJSIPs header parser crashes on incoming calls. > When compiling with -O2 or even -O3, everything works fine. XCode uses gcc > 4.2 underneath. > > I've narrowed it down to a loop that copies header-values into a temporary > header-structure in pjsip_dlg_update_remote_cap(). > > ? ? ? ?while (hdr) { > ? ? ? ? ? ? ? ?unsigned j; > ? ? ? ? ? ? ? ?/* Append the header content to temporary header */ > ? ? ? ? ? ? ? ?for(j=0; j<hdr->count && > ?tmp_hdr.count<PJSIP_GENERIC_ARRAY_MAX_COUNT; ++j) > ? ? ? ? ? ? ? ?{ > ? ? ? ? ? ? ? ? ? ? ? ?tmp_hdr.values[tmp_hdr.count++] = hdr->values[j]; > ? ? ? ? ? ? ? ?} > > ? ? ? ? ? ? ? ?/* Get the next header for this capability */ > ? ? ? ? ? ? ? ?hdr = (const pjsip_generic_array_hdr*) > ? ? ? ? ? ? ? ? ? ? ? ?pjsip_msg_find_hdr(msg, htypes[i], hdr->next); > ? ? ? ?} > > Looks good to me. But shortly after that, some pj_strdup (from > pjsip_hdr_clone) tries to copy those strings from tmp_hdr.values and > there's only garbage in tmp_hdr.values. tmp_hdr.count is fine though. > > When I modify the code by adding just a printf below(!!!) the while-loop, > gcc's optimizer is brought back to sanity again and the values are copied > just fine. > > ? ? ? ?while (hdr) { > ? ? ? ? ? ? ? ?unsigned j; > ? ? ? ? ? ? ? ?/* Append the header content to temporary header */ > ? ? ? ? ? ? ? ?for(j=0; j<hdr->count && > ?tmp_hdr.count<PJSIP_GENERIC_ARRAY_MAX_COUNT; ++j) > ? ? ? ? ? ? ? ?{ > ? ? ? ? ? ? ? ? ? ? ? ?tmp_hdr.values[tmp_hdr.count++] = hdr->values[j]; > ? ? ? ? ? ? ? ?} > > ? ? ? ? ? ? ? ?/* Get the next header for this capability */ > ? ? ? ? ? ? ? ?hdr = (const pjsip_generic_array_hdr*) > ? ? ? ? ? ? ? ? ? ? ? ?pjsip_msg_find_hdr(msg, htypes[i], hdr->next); > ? ? ? ?} > ? ? ? ?printf("[tmp_hdr] %s values (%d)\n", tmp_hdr.name.ptr, > tmp_hdr.count); > > An alterative "fix" was to add a printf on some tmp_hdr value inside the > inner for loop. So in the end I think, gcc gets something wrong by > optimizing access to tmp_hdr too much. > > Does anyone know what the real source of the problem might be? What has > Apple done to good old gcc? Or is this even reproducable on a Unix/Linux > platform? Or is it just me? > > Thanks in advance for any comment, > Sebastian. > > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >
