On Sun, 22 May 2022 05:00:21 GMT, Kim Barrett <kbarr...@openjdk.org> wrote:
>> I guess GCC cannot understand `assert(dest != NULL` immediately preceding it. >> >> >> In file included from >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceIdLoadBarrier.inline.hpp:33, >> from >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp:30, >> from >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/support/jfrJdkJfrEvent.cpp:30: >> In function 'void set_form(jbyte, jbyte*) [with jbyte (* op)(jbyte, jbyte) = >> traceid_or]', >> inlined from 'void set(jbyte, jbyte*)' at >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceIdBits.inline.hpp:129:23, >> inlined from 'static void JfrTraceIdBits::store(jbyte, const T*) [with T >> = Klass]' at >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceIdBits.inline.hpp:135:6, >> inlined from 'static void JfrTraceId::tag_as_jdk_jfr_event(const >> Klass*)' at >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/recorder/checkpoint/types/traceid/jfrTraceId.inline.hpp:106:3, >> inlined from 'static void JdkJfrEvent::tag_as(const Klass*)' at >> /home/ysuenaga/github-forked/jdk/src/hotspot/share/jfr/support/jfrJdkJfrEvent.cpp:176:35: > > I don't think this warning has anything to do with that NULL check. But I'm > still not understanding what it is warning about. The "region of size 0" part > of the warning message seems important, but I'm not (yet?) seeing how it could > be coming up with that. The code involved here is pretty contorted... It might be GCC bug... https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578 This issue is for integer literal, but [Comment 29](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578#c29) mentions address calculation (e.g. `NULL + offset`) - it is similar the problem in jfrTraceIdBits.inline.hp because `dest` comes from `low_addr()` (`addr + low_offset`). ------------- PR: https://git.openjdk.java.net/jdk/pull/8646
