[PATCH 2/3] perf tests: Don't tail call optimize in unwind test

From: Ian Rogers
Date: Sat May 30 2020 - 04:20:47 EST


The tail call optimization can unexpectedly make the stack smaller and
cause the test to fail.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/tests/dwarf-unwind.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
index 779ce280a0e9..2a0dac81f44c 100644
--- a/tools/perf/tests/dwarf-unwind.c
+++ b/tools/perf/tests/dwarf-unwind.c
@@ -94,7 +94,7 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
return strcmp((const char *) symbol, funcs[idx]);
}

-noinline int test_dwarf_unwind__thread(struct thread *thread)
+__no_tail_call noinline int test_dwarf_unwind__thread(struct thread *thread)
{
struct perf_sample sample;
unsigned long cnt = 0;
@@ -125,7 +125,7 @@ noinline int test_dwarf_unwind__thread(struct thread *thread)

static int global_unwind_retval = -INT_MAX;

-noinline int test_dwarf_unwind__compare(void *p1, void *p2)
+__no_tail_call noinline int test_dwarf_unwind__compare(void *p1, void *p2)
{
/* Any possible value should be 'thread' */
struct thread *thread = *(struct thread **)p1;
@@ -144,7 +144,7 @@ noinline int test_dwarf_unwind__compare(void *p1, void *p2)
return p1 - p2;
}

-noinline int test_dwarf_unwind__krava_3(struct thread *thread)
+__no_tail_call noinline int test_dwarf_unwind__krava_3(struct thread *thread)
{
struct thread *array[2] = {thread, thread};
void *fp = &bsearch;
@@ -163,12 +163,12 @@ noinline int test_dwarf_unwind__krava_3(struct thread *thread)
return global_unwind_retval;
}

-noinline int test_dwarf_unwind__krava_2(struct thread *thread)
+__no_tail_call noinline int test_dwarf_unwind__krava_2(struct thread *thread)
{
return test_dwarf_unwind__krava_3(thread);
}

-noinline int test_dwarf_unwind__krava_1(struct thread *thread)
+__no_tail_call noinline int test_dwarf_unwind__krava_1(struct thread *thread)
{
return test_dwarf_unwind__krava_2(thread);
}
--
2.27.0.rc2.251.g90737beb825-goog