perf tools: Compile scriptlets to BPF objects when passing '.c' to --event

This patch provides infrastructure for passing source files to --event
directly using:

 # perf record --event bpf-file.c command

This patch does following works:

 1) Allow passing '.c' file to '--event'. parse_events_load_bpf() is
    expanded to allow caller tell it whether the passed file is source
    file or object.

 2) llvm__compile_bpf() is called to compile the '.c' file, the result
    is saved into memory. Use bpf_object__open_buffer() to load the
    in-memory object.

Introduces a bpf-script-example.c so we can manually test it:

 # perf record --clang-opt "-DLINUX_VERSION_CODE=0x40200" --event ./bpf-script-example.c sleep 1

Note that '--clang-opt' must put before '--event'.

Futher patches will merge it into a testcase so can be tested automatically.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kaixu Xia <xiakaixu@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1444826502-49291-10-git-send-email-wangnan0@huawei.com
Signed-off-by: He Kuang <hekuang@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index cee8c61..bee6058 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -626,11 +626,12 @@ errout:
 
 int parse_events_load_bpf(struct parse_events_evlist *data,
 			  struct list_head *list,
-			  char *bpf_file_name)
+			  char *bpf_file_name,
+			  bool source)
 {
 	struct bpf_object *obj;
 
-	obj = bpf__prepare_load(bpf_file_name);
+	obj = bpf__prepare_load(bpf_file_name, source);
 	if (IS_ERR(obj) || !obj) {
 		char errbuf[BUFSIZ];
 		int err;