libbpf: add bpf_core_type_matches() helper macro

This patch finalizes support for the proposed type match relation in libbpf by
adding bpf_core_type_matches() macro which emits TYPE_MATCH relocation.

Clang support for this relocation was added in [0].

  [0] https://reviews.llvm.org/D126838

Signed-off-by: Daniel Müller <deso@posteo.net>¬
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>¬
Link: https://lore.kernel.org/bpf/20220628160127.607834-7-deso@posteo.net¬
This commit is contained in:
Andrii Nakryiko 2022-07-05 20:56:48 -07:00
parent ec6209c8d4
commit b8a195dc29

View file

@ -184,6 +184,16 @@ enum bpf_enum_value_kind {
#define bpf_core_type_exists(type) \
__builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_EXISTS)
/*
* Convenience macro to check that provided named type
* (struct/union/enum/typedef) "matches" that in a target kernel.
* Returns:
* 1, if the type matches in the target kernel's BTF;
* 0, if the type does not match any in the target kernel
*/
#define bpf_core_type_matches(type) \
__builtin_preserve_type_info(*(typeof(type) *)0, BPF_TYPE_MATCHES)
/*
* Convenience macro to get the byte size of a provided named type
* (struct/union/enum/typedef) in a target kernel.