Add enum definition for Clang's __builtin_preserve_field_info() second argument (info_kind). Currently only byte offset and existence are supported. Corresponding Clang changes introducing this built-in can be found at [0] [0] https://reviews.llvm.org/D67980 Signed-off-by: Andrii Nakryiko <andriin@xxxxxx> --- tools/lib/bpf/bpf_core_read.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/tools/lib/bpf/bpf_core_read.h b/tools/lib/bpf/bpf_core_read.h index 4daf04c25493..5a5cc88621a9 100644 --- a/tools/lib/bpf/bpf_core_read.h +++ b/tools/lib/bpf/bpf_core_read.h @@ -2,6 +2,18 @@ #ifndef __BPF_CORE_READ_H__ #define __BPF_CORE_READ_H__ +/* enum bpf_field_info_kind is passed as a second argument into + * __builtin_preserve_field_info() built-in to get a specific aspect of + * a field, captured as a first argument. __builtin_preserve_field_info(field, + * info_kind) returns __u32 integer and produces BTF field relocation, which + * is understood and processed by libbpf during BPF object loading. See + * selftests/bpf for examples. + */ +enum bpf_field_info_kind { + BPF_FI_BYTE_OFFSET = 0, /* field byte offset */ + BPF_FI_EXISTS = 2, /* whether field exists in target kernel */ +}; + /* * bpf_core_read() abstracts away bpf_probe_read() call and captures offset * relocation for source address using __builtin_preserve_access_index() -- 2.17.1
