[PATCH v2 1/4] perf tool: Change fields type in cap_user_time_short

From: Leo Yan
Date: Wed Apr 28 2021 - 08:00:09 EST


C standard claims "An object declared as type _Bool is large enough to
store the values 0 and 1", bool type size can be 1 byte or larger than
1 byte. Thus it's uncertian for bool type size with different
compilers.

This patch changes the bool type in structure cap_user_time_short to
__u8 type, and pads extra bytes for 8-byte alignment; this can give
reliable structure size.

Suggested-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Fixes: d110162cafc8 ("perf tsc: Support cap_user_time_short for event TIME_CONV")
Signed-off-by: Leo Yan <leo.yan@xxxxxxxxxx>
---
tools/lib/perf/include/perf/event.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/lib/perf/include/perf/event.h b/tools/lib/perf/include/perf/event.h
index d82054225fcc..48583e441d9b 100644
--- a/tools/lib/perf/include/perf/event.h
+++ b/tools/lib/perf/include/perf/event.h
@@ -346,8 +346,9 @@ struct perf_record_time_conv {
__u64 time_zero;
__u64 time_cycles;
__u64 time_mask;
- bool cap_user_time_zero;
- bool cap_user_time_short;
+ __u8 cap_user_time_zero;
+ __u8 cap_user_time_short;
+ __u8 reserved[6]; /* For alignment */
};

struct perf_record_header_feature {
--
2.25.1