common: Fix clang compilation

[byo]

Signed-off-by: Bartłomiej Święcki bartlomiej.swiecki@corp.ovh.com

[wjwithagen]

@byo
Code now compiles on FreeBSD/Clang

[liuchang0812]

hi, could we merge it now? I need this patch.

[tchaikov]

could use memcpy() for better performance.

[tchaikov]

@byo on a second thought, we can also leverage std::array for this

diff --git a/src/common/perf_histogram.h b/src/common/perf_histogram.h
index 6d315905db..99274d765d 100644
--- a/src/common/perf_histogram.h
+++ b/src/common/perf_histogram.h
@@ -20,6 +20,7 @@
 #include "include/int_types.h"

 #include <memory>
+#include <array>

 class PerfHistogramCommon {
 public:
@@ -133,7 +134,7 @@ protected:
   std::unique_ptr<atomic64_t[]> m_rawData;

   /// Configuration of axes
-  axis_config_d m_axes_config[DIM];
+  std::array<axis_config_d,DIM> m_axes_config;

   /// Dump histogram counters to a formatter
   void dump_formatted_values(ceph::Formatter *f) const {
@@ -145,8 +146,8 @@ protected:
   /// Get number of all histogram counters
   int64_t get_raw_size() {
     int64_t ret = 1;
-    for (int i = 0; i < DIM; ++i) {
-      ret *= m_axes_config[i].m_buckets;
+    for (const auto &ac : m_axes_config) {
+      ret *= ac.m_buckets;
     }
     return ret;
   }

[byo]

@tchaikov Great idea! I guess that's what std::array was created for. And I'm almost sure that copying such array to another one would be automatically converted to memcpy if the element type is trivially copyable.

Will give it a try in a second.

[tchaikov]

@liuchang0812 it needs an approval and a qa run.

[liuchang0812]

@tchaikov OK

[byo]

@tchaikov Changed as you suggested, looks much better now, also added small unit test to ensure the copy works correctly.

[byo]

jenkins retest this please

[tchaikov]

• http://pulpito.ceph.com/kchai-2017-02-17_10:27:51-rados-wip-kefu-testing---basic-mira/
• http://pulpito.ceph.com/kchai-2017-02-18_07:46:40-rados-wip-kefu-testing---basic-mira/