On Thu, Aug 7, 2025 at 7:42 AM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote: > > This is no substitute for link-time BTF deduplication of course, but > it does provide a simple way to see the BTF that gcc generates for vmlinux. > > The idea is that we can explore differences in BTF generation across > the various combinations > > 1. debug info source: DWARF; dedup done via pahole (traditional) > 2. debug info source: compiler-generated BTF; dedup done via pahole (above) > 3. debug info source: compiler-generated BTF; dedup done via linker (TBD) > > Handling 3 - linker-based dedup - will require BTF archives so that is the > next step we need to explore. Overall, the patch set makes sense and we need to make this step in pahole, but before we start any discussion about 3 and BTF archives the 1 and 2 above need to reach parity. Not just being close enough, but an exact equivalence. But, frankly, gcc support for btf_decl_tags is much much higher priority than any of this. We're tired of adding hacks through the bpf subsystem, because gcc cannot do decl_tags. Here are the hacks that will be removed: 1. BTF_TYPE_SAFE* 2. raw_tp_null_args[] 3. KF_ARENA_ARG and probably other cases.
