perf callchain: Setup callchain properly in pipe mode

Callchains are automatically initialized by checking on event's
sample_type. For pipe mode we need to put this check into attr event
code.

Moving the callchains setup code into callchain_param_setup function and
calling it from attr event process code.

This enables pipe output having callchains, like:

  # perf record -g -e 'raw_syscalls:sys_enter' true | perf script
  # perf record -g -e 'raw_syscalls:sys_enter' true | perf report

Committer notes:

We still need the next patch for the above output to work.

Reported-by: Paul Khuong <pvk@pvk.ca>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lore.kernel.org/lkml/20200507095024.2789147-5-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 818aa4e..2775b75 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -1599,3 +1599,17 @@ void callchain_cursor_reset(struct callchain_cursor *cursor)
 	for (node = cursor->first; node != NULL; node = node->next)
 		map__zput(node->ms.map);
 }
+
+void callchain_param_setup(u64 sample_type)
+{
+	if (symbol_conf.use_callchain || symbol_conf.cumulate_callchain) {
+		if ((sample_type & PERF_SAMPLE_REGS_USER) &&
+		    (sample_type & PERF_SAMPLE_STACK_USER)) {
+			callchain_param.record_mode = CALLCHAIN_DWARF;
+			dwarf_callchain_users = true;
+		} else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+			callchain_param.record_mode = CALLCHAIN_LBR;
+		else
+			callchain_param.record_mode = CALLCHAIN_FP;
+	}
+}