On Wed, Nov 4, 2020 at 9:53 AM 'Nick Desaulniers' via Clang Built Linux <clang-built-linux@xxxxxxxxxxxxxxxx> 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: Fangrui Song <maskray@xxxxxxxxxx> > Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Makefile | 14 ++++++++------ > lib/Kconfig.debug | 19 +++++++++++++++---- > 2 files changed, 23 insertions(+), 10 deletions(-) > > diff --git a/Makefile b/Makefile > index 75b1a3dcbf30..e23786a4c1c7 100644 > --- a/Makefile > +++ b/Makefile > @@ -826,12 +826,14 @@ else > DEBUG_CFLAGS += -g > endif > > -ifndef LLVM_IAS > -KBUILD_AFLAGS += -Wa,-gdwarf-2 > -endif > - > -ifdef CONFIG_DEBUG_INFO_DWARF4 > -DEBUG_CFLAGS += -gdwarf-4 > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF2) := 2 > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4 > +DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y) > +ifneq ($(dwarf-version-y)$(LLVM_IAS),21) > +# Binutils 2.35+ required for -gdwarf-4+ support. > +dwarf-aflag := $(call as-option,-Wa$(comma)-gdwarf-$(dwarf-version-y)) > +DEBUG_CFLAGS += $(dwarf-aflag) This changes the behavior. For the Dwarf-2 case, Previously, -gdwarf-2 was passed to $(CC), so the debug info was generated by gcc. Now, -Wa,-gdwarf-2 is passed to $(CC). -gdwarf-2 is handled by GNU as. So, the source info points to /tmp/<hash>.s instead of the original .c file. Handling the Dwarf capability is very complicated. Are you still working for v3? > +KBUILD_AFLAGS += $(dwarf-aflag) > endif > > ifdef CONFIG_DEBUG_INFO_REDUCED > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 83a860126897..03c494eefabd 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -256,14 +256,25 @@ config DEBUG_INFO_SPLIT > to know about the .dwo files and include them. > Incompatible with older versions of ccache. > > +choice > + prompt "DWARF version" > + help > + Which version of DWARF debug info to emit. > + > +config DEBUG_INFO_DWARF2 > + bool "Generate DWARF v2 debuginfo" > + help > + Generate DWARF v2 debug info. > + > config DEBUG_INFO_DWARF4 > bool "Generate dwarf4 debuginfo" > depends on $(cc-option,-gdwarf-4) > help > - Generate dwarf4 debug info. This requires recent versions > - of gcc and gdb. It makes the debug information larger. > - But it significantly improves the success of resolving > - variables in gdb on optimized code. > + Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. > + It makes the debug information larger, but it significantly > + improves the success of resolving variables in gdb on optimized code. > + > +endchoice # "DWARF version" > > config DEBUG_INFO_BTF > bool "Generate BTF typeinfo" > -- > 2.29.1.341.ge80a0c044ae-goog > > -- > You received this message because you are subscribed to the Google Groups "Clang Built Linux" group. > To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-linux+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20201104005343.4192504-4-ndesaulniers%40google.com. -- Best Regards Masahiro Yamada
