perf script: Initialize callchain_param.record_mode

Milian Wolff reported non functional DWARF unwind under perf script. The
reason is that perf script does not properly configure
callchain_param.record_mode, which is needed by unwind code.

Stealing the code from report and leaving the place for more
initialization code in a hope we could merge it with
report__setup_sample_type one day.

Reported-by: Milian Wolff <mail@milianw.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Milian Wolff <milian.wolff@kdab.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20150813071724.GA21322@krava.brq.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-script.c

@@ -1561,6 +1561,22 @@ static int have_cmd(int argc, const char **argv)
 	return 0;
 }
 
+static void script__setup_sample_type(struct perf_script *script)
+{
+	struct perf_session *session = script->session;
+	u64 sample_type = perf_evlist__combined_sample_type(session->evlist);
+
+	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;
+		else if (sample_type & PERF_SAMPLE_BRANCH_STACK)
+			callchain_param.record_mode = CALLCHAIN_LBR;
+		else
+			callchain_param.record_mode = CALLCHAIN_FP;
+	}
+}
+
 int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	bool show_full_info = false;
@@ -1849,6 +1865,7 @@ int cmd_script(int argc, const char **argv, const char *prefix __maybe_unused)
 		goto out_delete;
 
 	script.session = session;
+	script__setup_sample_type(&script);
 
 	session->itrace_synth_opts = &itrace_synth_opts;