[PATCH v3 1/4] perf tool: Change fields type in perf_record_time_conv

From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
	Steve MacLean <Steve.MacLean@Microsoft.com>,
	Yonatan Goldschmidt <yonatan.goldschmidt@granulate.io>,
	Kan Liang <kan.liang@linux.intel.com>,
	linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v3 1/4] perf tool: Change fields type in perf_record_time_conv
Date: Wed, 28 Apr 2021 20:09:12 +0800	[thread overview]
Message-ID: <20210428120915.7123-2-leo.yan@linaro.org> (raw)
In-Reply-To: <20210428120915.7123-1-leo.yan@linaro.org>

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 perf_record_time_conv to
__u8 type, and pads extra bytes for 8-byte alignment; this can give
reliable structure size.

Suggested-by: Adrian Hunter <adrian.hunter@intel.com>
Fixes: d110162cafc8 ("perf tsc: Support cap_user_time_short for event TIME_CONV")
Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 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

