linux/tools/build/feature/test-libbpf-strings.c
Blake Jones 1d0654b7fd perf build: detect support for libbpf's emit_strings option
This creates a config option that detects libbpf's ability to display
character arrays as strings, which was just added to the BPF tree
(https://git.kernel.org/bpf/bpf-next/c/87c9c79a02b4).

To test this change, I built perf (from later in this patch set) with:

 - static libbpf (default, using source from kernel tree)
 - dynamic libbpf (LIBBPF_DYNAMIC=1 LIBBPF_INCLUDE=/usr/local/include)

For both the static and dynamic versions, I used headers with and without
the ".emit_strings" option.

I verified that of the four resulting binaries, the two with
".emit_strings" would successfully record BPF_METADATA events, and the two
without wouldn't.  All four binaries would successfully display
BPF_METADATA events, because the relevant bit of libbpf code is only used
during "perf record".

Signed-off-by: Blake Jones <blakejones@google.com>
Link: https://lore.kernel.org/r/20250612194939.162730-2-blakejones@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-06-20 14:48:14 -07:00

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C

// SPDX-License-Identifier: GPL-2.0
#include <bpf/btf.h>
int main(void)
{
struct btf_dump_type_data_opts opts;
opts.emit_strings = 0;
return opts.emit_strings;
}