[llvm-dev] How to handle DWARF Missing due to function elimination?

[chuanqi.xcq via llvm-dev]

  Hi,

Although it looks like the same problem within the link (I met this within ThinLTO and bug 48790 met in LTO), it can't help after I revert  e08f205f. (You mentioned 93592b726c7 but I believe it shouldn't be true).
I met this in a complex production code. I would try to give an minimal repro if possible.

Thanks,
Chuanqi


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From:David Blaikie <dblaikie at gmail.com>
Send Time:2021年5月28日(星期五) 02:01
To:Jeremy Morse <jeremy.morse.llvm at gmail.com>
Cc:chuanqi.xcq <yedeng.yd at linux.alibaba.com>; llvm-dev at lists.llvm.org <llvm-dev at lists.llvm.org>; aprantl <aprantl at apple.com>
Subject:Re: How to handle DWARF Missing due to function elimination?

Yeah - would be good to know what the examples are - generally that is not expected (even with linker GC or other cases of symbol removal) & so is most likely something to be fixed in LLVM - but yeah, if the debugger is actually /crashing/ that's also not good, and it shouldn't do that (but lesser problem, because it also shouldn't encounter debug info like this, generally).
On Thu, May 27, 2021 at 4:47 AM Jeremy Morse <jeremy.morse.llvm at gmail.com> wrote:
Hi Chuanqi,

 On Thu, May 27, 2021 at 12:11 PM chuanqi.xcq
 <yedeng.yd at linux.alibaba.com> wrote:
 > The gdb would blame when it finds 0x0123456 doesn't refer to any functions in dwarf format.

 This is really interesting -- if you run "llvm-dwarfdump -verify" on
 the output file, does it too complain about an invalid DIE reference?

 There's a known issue with very complicated LTO builds that causes
 something similar:

https://bugs.llvm.org/show_bug.cgi?id=48790

 Reverting 93592b726c7 locally will tell you whether it's that or not.

 --
 Thanks,
 Jeremy

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