[Bug 1997161] Re: libunwind-dev has wrong LTO data

[Matthias Klose]

The real issue is, that the .a files in the libunwind-dev package are
not stripped, and therefore the LTO information is kept in these files.
This is done by intent in the packaging. Trying to figure why ...

In the meantime the least invasive thing to do is to just rebuild with
GCC 11.4.

** Also affects: libunwind (Ubuntu Jammy)
   Importance: Undecided
       Status: New

** Also affects: llvm-toolchain-14 (Ubuntu Jammy)
   Importance: Undecided
       Status: New

** No longer affects: llvm-toolchain-14 (Ubuntu Jammy)

** Changed in: llvm-toolchain-14 (Ubuntu)
       Status: New => Invalid

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Title:
  libunwind-dev has wrong LTO data

Status in libunwind package in Ubuntu:
  Confirmed
Status in llvm-toolchain-14 package in Ubuntu:
  Invalid
Status in libunwind source package in Jammy:
  New

Bug description:
  When linking libunwind into my program I get the following message:

  lto1: fatal error: bytecode stream in file '/usr/lib/gcc/x86_64-linux-
  gnu/11/../../../x86_64-linux-gnu/libunwind-x86_64.a' generated with
  LTO version 11.2 instead of the expected 11.3

  LTO stands for link time optimization.

  My guess is that libunwind-x86_64.a in Ubuntu repositories was
  compiled with earlier gcc 11.2, but the gcc version on this new
  installation of 22.04 is 11.3.

  I am not certain whether the right fix is to recompile with newer
  compiler version, or to make the library without turning on link time
  optimization options. libunwind is used for debugging, so there is no
  obvious benefit in enabling link time optimization for this library.

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