DWARF v5 is the latest standard of the DWARF debug info format. DWARF5 wins significantly in terms of size when mixed with compression (CONFIG_DEBUG_INFO_COMPRESSED). Link: http://www.dwarfstd.org/doc/DWARF5.pdf Patch 1 is a fixup already sent, but necessary for trying to use LLVM_IAS=1 with ToT LLVM. https://lore.kernel.org/stable/20201103012358.168682-1-maskray@xxxxxxxxxx/ Patches 2 and 3 are cleanups that lay the ground work and aren't DWARF v5 specific. In particular, I would like to see Patch 2 sent to stable so that Android and CrOS can move to LLVM_IAS=1 ASAP. Patch 4 implements Kconfig and Kbuild support for DWARFv5. Changes from the RFC: * split patch in 3 patch series, include Fangrui's patch, too. * prefer `DWARF vX` format, as per Fangrui. * use spaces between assignment in Makefile as per Masahiro. * simplify setting dwarf-version-y as per Masahiro. * indent `prompt` in Kconfig change as per Masahiro. * remove explicit default in Kconfig as per Masahiro. * add comments to test_dwarf5_support.sh. * change echo in test_dwarf5_support.sh as per Masahiro. * remove -u from test_dwarf5_support.sh as per Masahiro. * add a -gdwarf-5 cc-option check to Kconfig as per Jakub. Fangrui Song (1): x86_64: Change .weak to SYM_FUNC_START_WEAK for arch/x86/lib/mem*_64.S Nick Desaulniers (3): Kbuild: do not emit debug info for assembly with LLVM_IAS=1 Kbuild: make DWARF version a choice Kbuild: implement support for DWARF v5 Makefile | 13 +++++++++---- arch/x86/lib/memcpy_64.S | 4 +--- arch/x86/lib/memmove_64.S | 4 +--- arch/x86/lib/memset_64.S | 4 +--- include/asm-generic/vmlinux.lds.h | 6 +++++- lib/Kconfig.debug | 27 +++++++++++++++++++++++---- scripts/test_dwarf5_support.sh | 9 +++++++++ 7 files changed, 49 insertions(+), 18 deletions(-) create mode 100755 scripts/test_dwarf5_support.sh -- 2.29.1.341.ge80a0c044ae-goog
