On Thu, Feb 4, 2021 at 7:23 AM Masahiro Yamada <masahiroy@xxxxxxxxxx> wrote: > > On Sat, Jan 30, 2021 at 10:52 AM Nathan Chancellor <nathan@xxxxxxxxxx> wrote: > > > > On Fri, Jan 29, 2021 at 04:44:00PM -0800, Nick Desaulniers wrote: > > > 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. > > > > > > Suggested-by: Arvind Sankar <nivedita@xxxxxxxxxxxx> > > > Suggested-by: Fangrui Song <maskray@xxxxxxxxxx> > > > Suggested-by: Nathan Chancellor <nathan@xxxxxxxxxx> > > > Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> > > > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > > > > One comment below: > > > > Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx> > > > > > --- > > > Makefile | 5 ++--- > > > lib/Kconfig.debug | 16 +++++++++++----- > > > 2 files changed, 13 insertions(+), 8 deletions(-) > > > > > > diff --git a/Makefile b/Makefile > > > index 95ab9856f357..d2b4980807e0 100644 > > > --- a/Makefile > > > +++ b/Makefile > > > @@ -830,9 +830,8 @@ ifneq ($(LLVM_IAS),1) > > > KBUILD_AFLAGS += -Wa,-gdwarf-2 > > > > It is probably worth a comment somewhere that assembly files will still > > have DWARF v2. > > I agree. > Please noting the reason will be helpful. > > Could you summarize Jakub's comment in short? > https://patchwork.kernel.org/project/linux-kbuild/patch/20201022012106.1875129-1-ndesaulniers@xxxxxxxxxx/#23727667 > > > > > > > One more question. > > > Can we remove -g option like follows? > > > ifdef CONFIG_DEBUG_INFO_SPLIT > DEBUG_CFLAGS += -gsplit-dwarf > -else > -DEBUG_CFLAGS += -g > endif > > > > > > In the current mainline code, > -g is the only debug option > if CONFIG_DEBUG_INFO_DWARF4 is disabled. > > > The GCC manual says: > https://gcc.gnu.org/onlinedocs/gcc-10.2.0/gcc/Debugging-Options.html#Debugging-Options > > > -g > > Produce debugging information in the operating system’s > native format (stabs, COFF, XCOFF, or DWARF). > GDB can work with this debugging information. > > > Of course, we expect the -g option will produce > the debug info in the DWARF format. > > > > > > With this patch set applied, it is very explicit. > > Only the format type, but also the version. I mean: Not only the format type, but also the version is explicit. > The compiler will be given either > -gdwarf-4 or -gdwarf-5, > making the -g option redundant, I think. > > > > > > -- Best Regards Masahiro Yamada
