Hi Quentin, Thanks for your work. On 2022-09-06 14:36:06 +0100, Quentin Monnet wrote: > To disassemble instructions for JIT-ed programs, bpftool has relied on the > libbfd library. This has been problematic in the past: libbfd's interface > is not meant to be stable and has changed several times, hence the > detection of the two related features from the Makefile > (disassembler-four-args and disassembler-init-styled). When it comes to > shipping bpftool, this has also caused issues with several distribution > maintainers unwilling to support the feature (for example, Debian's page > for binutils-dev, libbfd's package, says: "Note that building Debian > packages which depend on the shared libbfd is Not Allowed."). > > This patchset adds support for LLVM as the primary library for > disassembling instructions for JIT-ed programs. > > We keep libbfd as a fallback. One reason for this is that currently it > works well, we have all we need in terms of features detection in the > Makefile, so it provides a fallback for disassembling JIT-ed programs if > libbfd is installed but LLVM is not. The other reason is that libbfd > supports nfp instruction for Netronome's SmartNICs and can be used to > disassemble offloaded programs, something that LLVM cannot do (Niklas > confirmed that the feature is still in use). However, if libbfd's interface > breaks again in the future, we might reconsider keeping support for it. I have tested the fallback method for NFP and it works as expected and one can dump the offloaded program. I know there is discussion about the output format of the LLVM path, but for the whole series from a NFP point of view, Tested-by: Niklas Söderlund <niklas.soderlund@xxxxxxxxxxxx> > > Quentin Monnet (7): > bpftool: Define _GNU_SOURCE only once > bpftool: Remove asserts from JIT disassembler > bpftool: Split FEATURE_TESTS/FEATURE_DISPLAY definitions in Makefile > bpftool: Group libbfd defs in Makefile, only pass them if we use > libbfd > bpftool: Refactor disassembler for JIT-ed programs > bpftool: Add LLVM as default library for disassembling JIT-ed programs > bpftool: Add llvm feature to "bpftool version" > > .../bpftool/Documentation/common_options.rst | 8 +- > tools/bpf/bpftool/Makefile | 65 +++-- > tools/bpf/bpftool/common.c | 2 + > tools/bpf/bpftool/iter.c | 2 + > tools/bpf/bpftool/jit_disasm.c | 244 ++++++++++++++---- > tools/bpf/bpftool/main.c | 10 + > tools/bpf/bpftool/main.h | 29 ++- > tools/bpf/bpftool/map.c | 1 - > tools/bpf/bpftool/net.c | 2 + > tools/bpf/bpftool/perf.c | 2 + > tools/bpf/bpftool/prog.c | 17 +- > tools/bpf/bpftool/xlated_dumper.c | 2 + > 12 files changed, 291 insertions(+), 93 deletions(-) > > -- > 2.34.1 > -- Kind Regards, Niklas Söderlund
