On Wed, Nov 4, 2020 at 9:54 AM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > DWARF v5 is the latest standard of the DWARF debug info format. > > Feature detection of DWARF5 is onerous, especially given that we've > removed $(AS), so we must query $(CC) for DWARF5 assembler directive > support. GNU `as` only recently gained support for specifying > -gdwarf-5. > > The DWARF version of a binary can be validated with: > $ llvm-dwarfdump vmlinux | head -n 5 | grep version > or > $ readelf --debug-dump=info vmlinux 2>/dev/null | grep Version > > DWARF5 wins significantly in terms of size when mixed with compression > (CONFIG_DEBUG_INFO_COMPRESSED). > > 363M vmlinux.clang12.dwarf5.compressed > 434M vmlinux.clang12.dwarf4.compressed > 439M vmlinux.clang12.dwarf2.compressed > 457M vmlinux.clang12.dwarf5 > 536M vmlinux.clang12.dwarf4 > 548M vmlinux.clang12.dwarf2 > > Link: http://www.dwarfstd.org/doc/DWARF5.pdf > Suggested-by: Masahiro Yamada <masahiroy@xxxxxxxxxx> > Suggested-by: Jakub Jelinek <jakub@xxxxxxxxxx> > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > --- > Makefile | 1 + > include/asm-generic/vmlinux.lds.h | 6 +++++- > lib/Kconfig.debug | 8 ++++++++ > scripts/test_dwarf5_support.sh | 9 +++++++++ > 4 files changed, 23 insertions(+), 1 deletion(-) > create mode 100755 scripts/test_dwarf5_support.sh > > diff --git a/Makefile b/Makefile > index e23786a4c1c7..9056bac0ff85 100644 > --- a/Makefile > +++ b/Makefile > @@ -828,6 +828,7 @@ endif > > dwarf-version-$(CONFIG_DEBUG_INFO_DWARF2) := 2 > dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4 > +dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5 > DEBUG_CFLAGS += -gdwarf-$(dwarf-version-y) > ifneq ($(dwarf-version-y)$(LLVM_IAS),21) > # Binutils 2.35+ required for -gdwarf-4+ support. > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index b2b3d81b1535..76ce62c77029 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -829,7 +829,11 @@ > .debug_types 0 : { *(.debug_types) } \ > /* DWARF 5 */ \ > .debug_macro 0 : { *(.debug_macro) } \ > - .debug_addr 0 : { *(.debug_addr) } > + .debug_addr 0 : { *(.debug_addr) } \ > + .debug_line_str 0 : { *(.debug_line_str) } \ > + .debug_loclists 0 : { *(.debug_loclists) } \ > + .debug_rnglists 0 : { *(.debug_rnglists) } \ > + .debug_str_offsets 0 : { *(.debug_str_offsets) } > > /* Stabs debugging sections. */ > #define STABS_DEBUG \ > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 03c494eefabd..c5b54ba51060 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -274,6 +274,14 @@ config DEBUG_INFO_DWARF4 > It makes the debug information larger, but it significantly > improves the success of resolving variables in gdb on optimized code. > > +config DEBUG_INFO_DWARF5 > + bool "Generate DWARF5 debuginfo" The choice menu looks like follows: (X) Generate DWARF v2 debuginfo ( ) Generate dwarf4 debuginfo ( ) Generate DWARF5 debuginfo Upper / Lower case inconsistency. -- Best Regards Masahiro Yamada
