On Tue, 11 Oct 2022 08:18:08 GMT, Christian Hagedorn <chaged...@openjdk.org> wrote:
>> The DWARF debugging symbols emitted by Clang is different from what GCC is >> emitting. While GCC produces a complete `.debug_aranges` section (which is >> required in the DWARF parser), Clang does not. As a result, the DWARF parser >> cannot find the necessary information to proceed and create the line number >> information: >> >> The `.debug_aranges` section contains address range to compilation unit >> offset mappings. The parsing algorithm can just walk through all these >> entries to find the correct address range that contains the library offset >> of the current pc. This gives us the compilation unit offset into the >> `.debug_info` section from where we can proceed to parse the line number >> information. >> >> Without a complete `.debug_aranges` section, we fail with an assertion that >> we could not find the correct entry. Since >> [JDK-8293402](https://bugs.openjdk.org/browse/JDK-8293402), we will still >> get the complete stack trace at least. Nevertheless, we should still fix >> this assertion failure of course. But that would require a different parsing >> approach. We need to parse the entire `.debug_info` section instead to get >> to the correct compilation unit. This, however, would require a lot more >> work. >> >> I therefore suggest to disable DWARF parsing for Clang for now and file an >> RFE to support Clang in the future with a different parsing approach. I'm >> using the `__clang__` `ifdef` to bail out in `get_source_info()` and disable >> the `gtests`. I've noticed that we are currently running the `gtests` with >> `NOT PRODUCT` which I think is not necessary - the gtests should also work >> fine with product builds. I've corrected this as well but that could also be >> done separately. >> >> Thanks, >> Christian > > Christian Hagedorn has updated the pull request with a new target base due to > a merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains six additional > commits since the last revision: > > - Always read full filename and strip prefix path and only then cut filename > to fit output buffer > - Merge branch 'master' into JDK-8293422 > - Merge branch 'master' into JDK-8293422 > - Review comments from Thomas > - Change old bailout fix to only apply to Clang versions older than 5.0 and > add new fix with -gdwarf-aranges + -gdwarf-4 for Clang 5.0+ > - 8293422: DWARF emitted by Clang cannot be parsed Build changes are approved. ------------- Marked as reviewed by ihse (Reviewer). PR: https://git.openjdk.org/jdk/pull/10287
