perf expr: Allow a double if expression

Some TMA metrics have double if expressions like:

  ( CPU_CLK_UNHALTED.THREAD / 2 ) * ( 1 + CPU_CLK_UNHALTED.ONE_THREAD_ACTIVE / CPU_CLK_UNHALTED.REF_XCLK ) ) if #core_wide < 1 else ( CPU_CLK_UNHALTED.THREAD_ANY / 2 ) if #SMT_on else CPU_CLK_UNHALTED.THREAD

This currently fails to parse as the left hand side if expression needs
to be in parentheses. By allowing the if expression to have a right hand
side that is an if expression we can parse the expression above, with
left to right evaluation order that matches languages like Python.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Ahmad Yasin <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Caleb Biggers <[email protected]>
Cc: Florian Fischer <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Kajol Jain <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Kshipra Bopardikar <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Miaoqian Lin <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Perry Taylor <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Samantha Alt <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Richter <[email protected]>
Cc: Xing Zhengjun <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 4 insertions, 0 deletions

diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
index 8bd719766814..6512f5e22045 100644
--- a/tools/perf/tests/expr.c
+++ b/tools/perf/tests/expr.c
@@ -95,6 +95,10 @@ static int test__expr(struct test_suite *t __maybe_unused, int subtest __maybe_u
 	ret |= test(ctx, "min(1,2) + 1", 2);
 	ret |= test(ctx, "max(1,2) + 1", 3);
 	ret |= test(ctx, "1+1 if 3*4 else 0", 2);
+	ret |= test(ctx, "100 if 1 else 200 if 1 else 300", 100);
+	ret |= test(ctx, "100 if 0 else 200 if 1 else 300", 200);
+	ret |= test(ctx, "100 if 1 else 200 if 0 else 300", 100);
+	ret |= test(ctx, "100 if 0 else 200 if 0 else 300", 300);
 	ret |= test(ctx, "1.1 + 2.1", 3.2);
 	ret |= test(ctx, ".1 + 2.", 2.1);
 	ret |= test(ctx, "d_ratio(1, 2)", 0.5);