Re: [PATCH v2 00/19] Implement DWARF modversions

[Sami Tolvanen]

Hi Jon,

On Thu, Aug 22, 2024 at 9:43 AM Jonathan Corbet <corbet@xxxxxxx> wrote:
>
> Sami Tolvanen <samitolvanen@xxxxxxxxxx> writes:
>
> > The first 16 patches of this series add a small tool for computing
> > symbol versions from DWARF, called gendwarfksyms. When passed a
> > list of exported symbols and an object file, the tool generates
> > an expanded type string for each symbol, and computes symbol CRCs
> > similarly to genksyms.
>
> Potentially silly question but: how similarly?  Specifically, do the two
> tools generate the same CRCs for the same symbols?  It seems that might
> be important for users transitioning to the new DWARF world order.

Reconstructing the source-based type strings genksyms uses from DWARF
wouldn't really be feasible, so the CRCs will be different. The
similar part is just that we build a human-readable string from the
debugging information and compute a CRC from it. If anyone is
interested in switching to gendwarfksyms, they'll have to rebuild all
their modules too.

Sami