perf debug: Move dump_stack() and sighandler_dump_stack() to debug.h

Two more out of util.h.

Link: http://lkml.kernel.org/n/tip-polkuxm1cpr06lbgue5pyqum@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/debug.c b/tools/perf/util/debug.c
index 6e1d7e1..9eaf86f 100644
--- a/tools/perf/util/debug.c
+++ b/tools/perf/util/debug.c
@@ -8,7 +8,9 @@
 #include <stdio.h>
 #include <api/debug.h>
 #include <linux/time64.h>
-
+#ifdef HAVE_BACKTRACE_SUPPORT
+#include <execinfo.h>
+#endif
 #include "cache.h"
 #include "color.h"
 #include "event.h"
@@ -248,3 +250,31 @@ void perf_debug_setup(void)
 {
 	libapi_set_print(pr_warning_wrapper, pr_warning_wrapper, pr_debug_wrapper);
 }
+
+/* Obtain a backtrace and print it to stdout. */
+#ifdef HAVE_BACKTRACE_SUPPORT
+void dump_stack(void)
+{
+	void *array[16];
+	size_t size = backtrace(array, ARRAY_SIZE(array));
+	char **strings = backtrace_symbols(array, size);
+	size_t i;
+
+	printf("Obtained %zd stack frames.\n", size);
+
+	for (i = 0; i < size; i++)
+		printf("%s\n", strings[i]);
+
+	free(strings);
+}
+#else
+void dump_stack(void) {}
+#endif
+
+void sighandler_dump_stack(int sig)
+{
+	psignal(sig, "perf");
+	dump_stack();
+	signal(sig, SIG_DFL);
+	raise(sig);
+}