perf evlist: Decode perf_event_attr->branch_sample_type

While trying to use --call-graph lbr in 'perf trace', since we only are
interested in the callchain for userspace, up to the callchain, I found
that 'perf evlist' is not decoding the branch_sample_type field, fix it.

Before:

  # perf record --call-graph lbr usleep 1
  # perf evlist -v
  cycles:ppp: size: 112, { sample_period, sample_freq }: 4000,
  sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|BRANCH_STACK,
  disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1,
  precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1,
  comm_exec: 1, branch_sample_type: 51201
                ^^^^^^^^^^^^^^^^^^^^^^^^^

After:

  # perf evlist -v
  cycles:ppp: size: 112, { sample_period, sample_freq }: 4000,
  sample_type: IP|TID|TIME|CALLCHAIN|CPU|PERIOD|BRANCH_STACK,
  disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, task: 1,
  precise_ip: 3, sample_id_all: 1, exclude_guest: 1, mmap2: 1,
  comm_exec: 1, branch_sample_type: USER|CALL_STACK|NO_FLAGS|NO_CYCLES
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Milian Wolff <milian.wolff@kdab.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-hozai7974u0ulgx13k96fcaw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -1231,6 +1231,21 @@ static void __p_sample_type(char *buf, size_t size, u64 value)
 	__p_bits(buf, size, value, bits);
 }
 
+static void __p_branch_sample_type(char *buf, size_t size, u64 value)
+{
+#define bit_name(n) { PERF_SAMPLE_BRANCH_##n, #n }
+	struct bit_names bits[] = {
+		bit_name(USER), bit_name(KERNEL), bit_name(HV), bit_name(ANY),
+		bit_name(ANY_CALL), bit_name(ANY_RETURN), bit_name(IND_CALL),
+		bit_name(ABORT_TX), bit_name(IN_TX), bit_name(NO_TX),
+		bit_name(COND), bit_name(CALL_STACK), bit_name(IND_JUMP),
+		bit_name(CALL), bit_name(NO_FLAGS), bit_name(NO_CYCLES),
+		{ .name = NULL, }
+	};
+#undef bit_name
+	__p_bits(buf, size, value, bits);
+}
+
 static void __p_read_format(char *buf, size_t size, u64 value)
 {
 #define bit_name(n) { PERF_FORMAT_##n, #n }
@@ -1249,6 +1264,7 @@ static void __p_read_format(char *buf, size_t size, u64 value)
 #define p_unsigned(val)		snprintf(buf, BUF_SIZE, "%"PRIu64, (uint64_t)(val))
 #define p_signed(val)		snprintf(buf, BUF_SIZE, "%"PRId64, (int64_t)(val))
 #define p_sample_type(val)	__p_sample_type(buf, BUF_SIZE, val)
+#define p_branch_sample_type(val) __p_branch_sample_type(buf, BUF_SIZE, val)
 #define p_read_format(val)	__p_read_format(buf, BUF_SIZE, val)
 
 #define PRINT_ATTRn(_n, _f, _p)				\
@@ -1305,7 +1321,7 @@ int perf_event_attr__fprintf(FILE *fp, struct perf_event_attr *attr,
 	PRINT_ATTRf(bp_type, p_unsigned);
 	PRINT_ATTRn("{ bp_addr, config1 }", bp_addr, p_hex);
 	PRINT_ATTRn("{ bp_len, config2 }", bp_len, p_hex);
-	PRINT_ATTRf(branch_sample_type, p_unsigned);
+	PRINT_ATTRf(branch_sample_type, p_branch_sample_type);
 	PRINT_ATTRf(sample_regs_user, p_hex);
 	PRINT_ATTRf(sample_stack_user, p_unsigned);
 	PRINT_ATTRf(clockid, p_signed);