> 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 pull request now contains 10 commits: - Merge branch 'master' into JDK-8293422 - Remove unused local variable - Update algorithm to print char by char, skipping file separators on the fly and only caring about the actual filename (ignore prefix path when reading) - Merge branch 'master' into JDK-8293422 - 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 ------------- Changes: https://git.openjdk.org/jdk/pull/10287/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10287&range=06 Stats: 162 lines in 5 files changed: 113 ins; 31 del; 18 mod Patch: https://git.openjdk.org/jdk/pull/10287.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10287/head:pull/10287 PR: https://git.openjdk.org/jdk/pull/10287
