perf test: Add callchain order setup for DWARF unwinder test

Adding callchain order setup for DWARF unwinder test. The test now runs
unwinder for both callee and caller orders.

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 <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1447772739-18471-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/dwarf-unwind.c

@@ -51,6 +51,12 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
 		"krava_1",
 		"test__dwarf_unwind"
 	};
+	/*
+	 * The funcs[MAX_STACK] array index, based on the
+	 * callchain order setup.
+	 */
+	int idx = callchain_param.order == ORDER_CALLER ?
+		  MAX_STACK - *cnt - 1 : *cnt;
 
 	if (*cnt >= MAX_STACK) {
 		pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
@@ -63,8 +69,10 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
 		return -1;
 	}
 
-	pr_debug("got: %s 0x%" PRIx64 "\n", symbol, entry->ip);
-	return strcmp((const char *) symbol, funcs[(*cnt)++]);
+	(*cnt)++;
+	pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n",
+		 symbol, entry->ip, funcs[idx]);
+	return strcmp((const char *) symbol, funcs[idx]);
 }
 
 __attribute__ ((noinline))
@@ -105,8 +113,16 @@ static int compare(void *p1, void *p2)
 	/* Any possible value should be 'thread' */
 	struct thread *thread = *(struct thread **)p1;
 
-	if (global_unwind_retval == -INT_MAX)
+	if (global_unwind_retval == -INT_MAX) {
+		/* Call unwinder twice for both callchain orders. */
+		callchain_param.order = ORDER_CALLER;
+
 		global_unwind_retval = unwind_thread(thread);
+		if (!global_unwind_retval) {
+			callchain_param.order = ORDER_CALLEE;
+			global_unwind_retval = unwind_thread(thread);
+		}
+	}
 
 	return p1 - p2;
 }