Building Python-3.14.0a2 with `--enable-bolt` fails with library not found error: `/usr/lib/libbolt_rt_instr.a`

[leon-matthews]

Bug report

Bug description:

I downloaded the source package from Python.org today and encountered an error when enabling BOLT optimisation:

$ sudo apt install llvm-bolt llvm-bolt-dev libbolt-dev
$ ./configure --enable-optimizations --enable-experimental-jit=yes --enable-bolt
...
BOLT-ERROR: library not found: /usr/lib/libbolt_rt_instr.a

The library file in question was installed by libbolt-dev, but into /usr/lib/llvm-19/lib/libbolt_rt_instr.a. Creating a symlink allowed the build to work, beautifully.

$ sudo ln -s /usr/lib/llvm-19/lib/libbolt_rt_instr.a /usr/lib/libbolt_rt_instr.a
$ ./configure --enable-optimizations --enable-experimental-jit=yes --enable-bolt
Success!...

I'm just running Ubuntu 24.10 on an AMD Ryzen 9 7950X3D and have installed LLVM et. al from its default repos.

CPython versions tested on:

3.14

Operating systems tested on:

Linux

[zanieb]

This error looks like it comes from BOLT and (as far as I can tell) we just invoke the BOLT binary. Could you share more logs?

I'm not sure there's an obvious way to resolve this here. I'm surprised the bolt binary would not correctly discovery its own libraries.

Does this reproduce today? My best guess is this was a problem with the system package for llvm-bolt.

[stratakis]

I'm doing some testing myself on the latest Fedora development version and while with the upstream sources I got no issues on my machine running stable Fedora, the rpm build errors out with the same issue.

Starting seeing this lately as I've been testing this config for a bit, so I suspect it could be due to some package update throughout the toolchain, as the bolt version remains the same (19.1.7).

It errors out as BOLT-ERROR: library not found: /usr/lib/libbolt_rt_instr.a but the package structure places this file in /usr/lib64

[stratakis]

This looks as a packaging issue on Fedora side, possibly on Ubuntu as well. Filled a bug: https://bugzilla.redhat.com/show_bug.cgi?id=2344830

[stratakis]

Actually it's an upstream issue. PR: llvm/llvm-project#126698

[zanieb]

Thank you for chasing that down!

[leon-matthews]

Nice work, thank you all very much!