perf test: Replace brstack test workload

So that it can get rid of requirement of a compiler. Also rename the
symbols to match with the perf test workload.

Signed-off-by: Namhyung Kim <[e-mail]>
Tested-by: James Clark <[e-mail]>
Acked-by: German Gomez <[e-mail]>
Cc: Adrian Hunter <[e-mail]>
Cc: Athira Jajeev <[e-mail]>
Cc: Ian Rogers <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Zhengjun Xing <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/tests/shell/test_brstack.sh

···
 # SPDX-License-Identifier: GPL-2.0
 # German Gomez <[e-mail]>, 2022
 
-# we need a C compiler to build the test programs
-# so bail if none is found
-if ! [ -x "$(command -v cc)" ]; then
-	echo "failed: no compiler, install gcc"
-	exit 2
-fi
-
 # skip the test if the hardware doesn't support branch stack sampling
 # and if the architecture doesn't support filter types: any,save_type,u
 if ! perf record -o- --no-buildid --branch-filter any,save_type,u -- true > /dev/null 2>&1 ; then
···
 fi
 
 TMPDIR=$(mktemp -d /tmp/__perf_test.program.XXXXX)
+TESTPROG="perf test -w brstack"
 
 cleanup() {
 	rm -rf $TMPDIR
···
 
 trap cleanup exit term int
 
-gen_test_program() {
-	# generate test program
-	cat << EOF > $1
-#define BENCH_RUNS 999999
-int cnt;
-void bar(void) {
-}			/* return */
-void foo(void) {
-	bar();		/* call */
-}			/* return */
-void bench(void) {
-  void (*foo_ind)(void) = foo;
-  if ((cnt++) % 3)	/* branch (cond) */
-    foo();		/* call */
-  bar();		/* call */
-  foo_ind();		/* call (ind) */
-}
-int main(void)
-{
-  int cnt = 0;
-  while (1) {
-    if ((cnt++) > BENCH_RUNS)
-      break;
-    bench();		/* call */
-  }			/* branch (uncond) */
-  return 0;
-}
-EOF
-}
-
 test_user_branches() {
 	echo "Testing user branch stack sampling"
 
-	gen_test_program "$TEMPDIR/program.c"
-	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
-
-	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
+	perf record -o $TMPDIR/perf.data --branch-filter any,save_type,u -- ${TESTPROG} > /dev/null 2>&1
 	perf script -i $TMPDIR/perf.data --fields brstacksym | xargs -n1 > $TMPDIR/perf.script
 
 	# example of branch entries:
-	# 	foo+0x14/bar+0x40/P/-/-/0/CALL
+	# 	brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL
 
 	set -x
-	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/IND_CALL$"	$TMPDIR/perf.script
-	egrep -m1 "^foo\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
-	egrep -m1 "^bench\+[^ ]*/foo\+[^ ]*/CALL$"	$TMPDIR/perf.script
-	egrep -m1 "^bench\+[^ ]*/bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
-	egrep -m1 "^bar\+[^ ]*/foo\+[^ ]*/RET$"		$TMPDIR/perf.script
-	egrep -m1 "^foo\+[^ ]*/bench\+[^ ]*/RET$"	$TMPDIR/perf.script
-	egrep -m1 "^bench\+[^ ]*/bench\+[^ ]*/COND$"	$TMPDIR/perf.script
-	egrep -m1 "^main\+[^ ]*/main\+[^ ]*/UNCOND$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET$"		$TMPDIR/perf.script
+	egrep -m1 "^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND$"	$TMPDIR/perf.script
+	egrep -m1 "^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND$"		$TMPDIR/perf.script
 	set +x
 
 	# some branch types are still not being tested:
···
 
 	echo "Testing branch stack filtering permutation ($filter,$expect)"
 
-	gen_test_program "$TEMPDIR/program.c"
-	cc -fno-inline -g "$TEMPDIR/program.c" -o $TMPDIR/a.out
-
-	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- $TMPDIR/a.out > /dev/null 2>&1
+	perf record -o $TMPDIR/perf.data --branch-filter $filter,save_type,u -- ${TESTPROG} > /dev/null 2>&1
 	perf script -i $TMPDIR/perf.data --fields brstack | xargs -n1 > $TMPDIR/perf.script
 
 	# fail if we find any branch type that doesn't match any of the expected ones