lkml.org 
[lkml]   [2021]   [Jan]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH v6 1/2] Kbuild: make DWARF version a choice
On Fri, Jan 29, 2021 at 12:17 PM Jakub Jelinek <jakub@redhat.com> wrote:
>
> On Fri, Jan 29, 2021 at 11:43:17AM -0800, Nick Desaulniers wrote:
> > Modifies CONFIG_DEBUG_INFO_DWARF4 to be a member of a choice. Adds an
> > explicit CONFIG_DEBUG_INFO_DWARF2, which is the default. Does so in a
> > way that's forward compatible with existing configs, and makes adding
> > future versions more straightforward.
> >
> > Suggested-by: Arvind Sankar <nivedita@alum.mit.edu>
> > Suggested-by: Fangrui Song <maskray@google.com>
> > Suggested-by: Nathan Chancellor <nathan@kernel.org>
> > Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > ---
> > Makefile | 6 +++---
> > lib/Kconfig.debug | 21 ++++++++++++++++-----
> > 2 files changed, 19 insertions(+), 8 deletions(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 95ab9856f357..20141cd9319e 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -830,9 +830,9 @@ ifneq ($(LLVM_IAS),1)
> > KBUILD_AFLAGS += -Wa,-gdwarf-2
> > endif
> >
> > -ifdef CONFIG_DEBUG_INFO_DWARF4
> > -DEBUG_CFLAGS += -gdwarf-4
> > -endif
> > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF2) := 2
> > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
> > +DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y)
>
> Why do you make DWARF2 the default? That seems a big step back from what
> the Makefile used to do before, where it defaulted to whatever DWARF version
> the compiler defaulted to?
> E.g. GCC 4.8 up to 10 defaults to -gdwarf-4 and GCC 11 will default to
> -gdwarf-5.
> DWARF2 is more than 27 years old standard, DWARF3 15 years old,
> DWARF4 over 10 years old and DWARF5 almost 4 years old...
> It is true that some tools aren't DWARF5 ready at this point, but with GCC
> defaulting to that it will change quickly, but at least DWARF4 support has
> been around for years.

I agree with you; I also do not want to change the existing defaults
in this series. That is a separate issue to address.

--
Thanks,
~Nick Desaulniers

\
 
 \ /
  Last update: 2021-01-29 21:21    [W:2.119 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site