Re: [RFC] perf trace: Fix compilation error for make NO_LIBBPF=1 DEBUG=1

From: Arnaldo Carvalho de Melo
Date: Mon May 18 2020 - 10:19:23 EST


Em Mon, May 18, 2020 at 04:10:27PM +0200, Jiri Olsa escreveu:
> I haven't tested if this breaks some perf trace functionality,
> hence RFC ;-)

Thanks for the patch, looks ok, applying, please let me know if you need
to do something else with it.

- Arnaldo

> The perf compilation fails for NO_LIBBPF=1 DEBUG=1 with:
>
> $ make NO_LIBBPF=1 DEBUG=1
> BUILD: Doing 'make -j8' parallel build
> CC builtin-trace.o
> LD perf-in.o
> LINK perf
> /usr/bin/ld: perf-in.o: in function `trace__find_bpf_map_by_name':
> /home/jolsa/kernel/linux-perf/tools/perf/builtin-trace.c:4608: undefined reference to `bpf_object__find_map_by_name'
> collect2: error: ld returned 1 exit status
> make[2]: *** [Makefile.perf:631: perf] Error 1
> make[1]: *** [Makefile.perf:225: sub-make] Error 2
> make: *** [Makefile:70: all] Error 2
>
> Moving trace__find_bpf_map_by_name calls under HAVE_LIBBPF_SUPPORT
> ifdef and add make test for this.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/perf/builtin-trace.c | 54 ++++++++++++++++++++++++--------------
> tools/perf/tests/make | 1 +
> 2 files changed, 35 insertions(+), 20 deletions(-)
>
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index 56bcf1ab19f8..61bafca1018a 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -3174,6 +3174,26 @@ static int trace__set_ev_qualifier_tp_filter(struct trace *trace)
> }
>
> #ifdef HAVE_LIBBPF_SUPPORT
> +static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace, const char *name)
> +{
> + if (trace->bpf_obj == NULL)
> + return NULL;
> +
> + return bpf_object__find_map_by_name(trace->bpf_obj, name);
> +}
> +
> +static void trace__set_bpf_map_filtered_pids(struct trace *trace)
> +{
> + trace->filter_pids.map = trace__find_bpf_map_by_name(trace, "pids_filtered");
> +}
> +
> +static void trace__set_bpf_map_syscalls(struct trace *trace)
> +{
> + trace->syscalls.map = trace__find_bpf_map_by_name(trace, "syscalls");
> + trace->syscalls.prog_array.sys_enter = trace__find_bpf_map_by_name(trace, "syscalls_sys_enter");
> + trace->syscalls.prog_array.sys_exit = trace__find_bpf_map_by_name(trace, "syscalls_sys_exit");
> +}
> +
> static struct bpf_program *trace__find_bpf_program_by_title(struct trace *trace, const char *name)
> {
> if (trace->bpf_obj == NULL)
> @@ -3512,6 +3532,20 @@ static void trace__delete_augmented_syscalls(struct trace *trace)
> trace->bpf_obj = NULL;
> }
> #else // HAVE_LIBBPF_SUPPORT
> +static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace __maybe_unused,
> + const char *name __maybe_unused)
> +{
> + return NULL;
> +}
> +
> +static void trace__set_bpf_map_filtered_pids(struct trace *trace __maybe_unused)
> +{
> +}
> +
> +static void trace__set_bpf_map_syscalls(struct trace *trace __maybe_unused)
> +{
> +}
> +
> static int trace__set_ev_qualifier_bpf_filter(struct trace *trace __maybe_unused)
> {
> return 0;
> @@ -4600,26 +4634,6 @@ static int trace__parse_cgroups(const struct option *opt, const char *str, int u
> return 0;
> }
>
> -static struct bpf_map *trace__find_bpf_map_by_name(struct trace *trace, const char *name)
> -{
> - if (trace->bpf_obj == NULL)
> - return NULL;
> -
> - return bpf_object__find_map_by_name(trace->bpf_obj, name);
> -}
> -
> -static void trace__set_bpf_map_filtered_pids(struct trace *trace)
> -{
> - trace->filter_pids.map = trace__find_bpf_map_by_name(trace, "pids_filtered");
> -}
> -
> -static void trace__set_bpf_map_syscalls(struct trace *trace)
> -{
> - trace->syscalls.map = trace__find_bpf_map_by_name(trace, "syscalls");
> - trace->syscalls.prog_array.sys_enter = trace__find_bpf_map_by_name(trace, "syscalls_sys_enter");
> - trace->syscalls.prog_array.sys_exit = trace__find_bpf_map_by_name(trace, "syscalls_sys_exit");
> -}
> -
> static int trace__config(const char *var, const char *value, void *arg)
> {
> struct trace *trace = arg;
> diff --git a/tools/perf/tests/make b/tools/perf/tests/make
> index 5d0c3a9c47a1..c3c59def9f87 100644
> --- a/tools/perf/tests/make
> +++ b/tools/perf/tests/make
> @@ -84,6 +84,7 @@ make_no_libaudit := NO_LIBAUDIT=1
> make_no_libbionic := NO_LIBBIONIC=1
> make_no_auxtrace := NO_AUXTRACE=1
> make_no_libbpf := NO_LIBBPF=1
> +make_no_libbpf_DEBUG := NO_LIBBPF=1 DEBUG=1
> make_no_libcrypto := NO_LIBCRYPTO=1
> make_with_babeltrace:= LIBBABELTRACE=1
> make_no_sdt := NO_SDT=1
> --
> 2.25.4
>

--

- Arnaldo