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-rw-r--r--tools/perf/tests/dwarf-unwind.c36
1 files changed, 34 insertions, 2 deletions
diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
index ab28cca2cb97..0bf06bec68c7 100644
--- a/tools/perf/tests/dwarf-unwind.c
+++ b/tools/perf/tests/dwarf-unwind.c
@@ -11,6 +11,9 @@
#include "thread.h"
#include "callchain.h"
+/* For bsearch. We try to unwind functions in shared object. */
+#include <stdlib.h>
+
static int mmap_handler(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample __maybe_unused,
@@ -28,7 +31,7 @@ static int init_live_machine(struct machine *machine)
mmap_handler, machine, true);
}
-#define MAX_STACK 6
+#define MAX_STACK 8
static int unwind_entry(struct unwind_entry *entry, void *arg)
{
@@ -37,6 +40,8 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
static const char *funcs[MAX_STACK] = {
"test__arch_unwind_sample",
"unwind_thread",
+ "compare",
+ "bsearch",
"krava_3",
"krava_2",
"krava_1",
@@ -88,10 +93,37 @@ static int unwind_thread(struct thread *thread)
return err;
}
+static int global_unwind_retval = -INT_MAX;
+
+__attribute__ ((noinline))
+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)
+ global_unwind_retval = unwind_thread(thread);
+
+ return p1 - p2;
+}
+
__attribute__ ((noinline))
static int krava_3(struct thread *thread)
{
- return unwind_thread(thread);
+ struct thread *array[2] = {thread, thread};
+ void *fp = &bsearch;
+ /*
+ * make _bsearch a volatile function pointer to
+ * prevent potential optimization, which may expand
+ * bsearch and call compare directly from this function,
+ * instead of libc shared object.
+ */
+ void *(*volatile _bsearch)(void *, void *, size_t,
+ size_t, int (*)(void *, void *));
+
+ _bsearch = fp;
+ _bsearch(array, &thread, 2, sizeof(struct thread **), compare);
+ return global_unwind_retval;
}
__attribute__ ((noinline))
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