On Fri, Jan 15, 2021 at 10:06 PM Nick Desaulniers <ndesaulniers@xxxxxxxxxx> wrote: > > 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 cleanup from Masahiro and isn't DWARF v5 specific. > Patch 2 is a cleanup that lays the ground work and isn't DWARF > v5 specific. > Patch 3 implements Kconfig and Kbuild support for DWARFv5. > > Changes from v4: > * drop set -e from script as per Nathan. > * add dependency on !CONFIG_DEBUG_INFO_BTF for DWARF v5 as per Sedat. > * Move LLVM_IAS=1 complexity from patch 2 to patch 3 as per Arvind and > Masahiro. Sorry it took me a few tries to understand the point (I > might still not), but it looks much cleaner this way. Sorry Nathan, I > did not carry forward your previous reviews as a result, but I would > appreciate if you could look again. > * Add Nathan's reviewed by tag to patch 1. > * Reword commit message for patch 3 to mention LLVM_IAS=1 and -gdwarf-5 > binutils addition later, and BTF issue. > * I still happen to see a pahole related error spew for the combination > of: > * LLVM=1 > * LLVM_IAS=1 > * CONFIG_DEBUG_INFO_DWARF4 > * CONFIG_DEBUG_INFO_BTF > Though they're non-fatal to the build. I'm not sure yet why removing > any one of the above prevents the warning spew. Maybe we'll need a v6. > En plus, I encountered breakage with GCC v10.2.1 and LLVM=1 and CONFIG_DEBUG_INFO_DWARF4. So might be good to add a "depends on !DEBUG_INFO_BTF" in this combination. I had some other small nits commented in the single patches. As requested in your previous patch-series, feel free to add my: Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> - Sedat - > Changes from v3: > > Changes as per Arvind: > * only add -Wa,-gdwarf-5 for (LLVM=1|CC=clang)+LLVM_IAS=0 builds. > * add -gdwarf-5 to Kconfig shell script. > * only run Kconfig shell script for Clang. > > Apologies to Sedat and Nathan; I appreciate previous testing/review, but > I did no carry forward your Tested-by and Reviewed-by tags, as the > patches have changed too much IMO. > > Changes from v2: > * Drop two of the earlier patches that have been accepted already. > * Add measurements with GCC 10.2 to commit message. > * Update help text as per Arvind with help from Caroline. > * Improve case/wording between DWARF Versions as per Masahiro. > > 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. > > *** BLURB HERE *** > > Masahiro Yamada (1): > Remove $(cc-option,-gdwarf-4) dependency from CONFIG_DEBUG_INFO_DWARF4 > > Nick Desaulniers (2): > Kbuild: make DWARF version a choice > Kbuild: implement support for DWARF v5 > > Makefile | 13 +++++++--- > include/asm-generic/vmlinux.lds.h | 6 ++++- > lib/Kconfig.debug | 42 +++++++++++++++++++++++++------ > scripts/test_dwarf5_support.sh | 8 ++++++ > 4 files changed, 57 insertions(+), 12 deletions(-) > create mode 100755 scripts/test_dwarf5_support.sh > > -- > 2.30.0.284.gd98b1dd5eaa7-goog >
