Messages in this thread | | | From | James Hilliard <> | Date | Thu, 9 Jun 2022 17:46:13 -0600 | Subject | Re: [PATCH 1/1] libbpf: replace typeof with __typeof__ for -std=c17 compatibility |
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On Thu, Jun 9, 2022 at 12:11 PM Andrii Nakryiko <andrii.nakryiko@gmail.com> wrote: > > On Wed, Jun 8, 2022 at 11:28 PM James Hilliard > <james.hilliard1@gmail.com> wrote: > > > > Fixes errors like: > > error: expected specifier-qualifier-list before 'typeof' > > 14 | #define __type(name, val) typeof(val) *name > > | ^~~~~~ > > ../src/core/bpf/socket_bind/socket-bind.bpf.c:25:9: note: in expansion of macro '__type' > > 25 | __type(key, __u32); > > | ^~~~~~ > > > > Signed-off-by: James Hilliard <james.hilliard1@gmail.com> > > --- > > If you follow DPDK link you gave me ([0]), you'll see that they ended up doing > > #ifndef typeof > #define typeof __typeof__ > #endif > > It's way more localized. Let's do that.
Won't that potentially leak the redefinition into external code including the header file?
I don't see a redefinition of typeof like that used elsewhere in the kernel.
However I do see __typeof__ used in many headers already so that approach seems to follow normal conventions and seems less risky.
FYI using -std=gnu17 instead of -std=c17 works around this issue with bpf-gcc at least so this issue isn't really a blocker like the SEC macro issue, I had just accidentally mixed the two issues up due to accidentally not clearing out some header files when testing, they seem to be entirely separate.
> > But also I tried to build libbpf-bootstrap with -std=c17 and > immediately ran into issue with asm, so we need to do the same with > asm -> __asm__. Can you please update your patch and fix both issues?
Are you hitting that with clang/llvm or bpf-gcc? It doesn't appear that the libbpf-bootstrap build system is set up to build with bpf-gcc yet.
> > [0] https://patches.dpdk.org/project/dpdk/patch/2601191342CEEE43887BDE71AB977258213F3012@irsmsx105.ger.corp.intel.com/ > [1] https://github.com/libbpf/libbpf-bootstrap > > > > tools/lib/bpf/bpf_core_read.h | 16 ++++++++-------- > > tools/lib/bpf/bpf_helpers.h | 4 ++-- > > tools/lib/bpf/bpf_tracing.h | 24 ++++++++++++------------ > > tools/lib/bpf/btf.h | 4 ++-- > > tools/lib/bpf/libbpf_internal.h | 6 +++--- > > tools/lib/bpf/usdt.bpf.h | 6 +++--- > > tools/lib/bpf/xsk.h | 12 ++++++------ > > 7 files changed, 36 insertions(+), 36 deletions(-) > > > > [...]
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