On Thu, 2021-02-04 at 11:18 -0800, Nick Desaulniers wrote:

On Thu, Feb 4, 2021 at 2:41 AM Mark Wielaard [off-list ref] wrote:

quoted

On Fri, Jan 29, 2021 at 04:44:00PM -0800, Nick Desaulniers wrote:

quoted

Modifies CONFIG_DEBUG_INFO_DWARF4 to be a member of a choice which is
the default. Does so in a way that's forward compatible with existing
configs, and makes adding future versions more straightforward.

GCC since ~4.8 has defaulted to this DWARF version implicitly.

And since GCC 11 it defaults to DWARF version 5.

It would be better to set the default to the DWARF version that the
compiler generates. So if the user doesn't select any version then it
should default to just -g (or -gdwarf).

I disagree.

https://lore.kernel.org/lkml/CAKwvOdk0zxewEOaFuqK0aSMz3vKNzDOgmez=-Dae4+bodsSg5w@mail.gmail.com/ (local)
"""
I agree that this patch takes away the compiler vendor's choice as to
what the implicit default choice is for dwarf version for the kernel.
(We, the Linux kernel, do so already for implicit default -std=gnuc*
as well). ...
But I'm
going to suggest we follow the Zen of Python: explicit is better than
implicit.
"""
We have a number of in tree and out of tree DWARF consumers that
aren't ready for DWARF v5.  Kernel developers need a way to disable
DWARF v5 until their dependencies are deployed or more widely
available.

I agree with Jakub. Now that GCC has defaulted to DWARF5 all the tools
have adopted to the new default version. And DWARF5 has been out for
more than 4 years already. It isn't unreasonable to assume that people
using GCC11 will also be using the rest of the toolchain that has moved
on. Which DWARF consumers are you concerned about not being ready for
GCC defaulting to DWARF5 once GCC11 is released?

Thanks,

Mark