[OpenMP] Fixed a bug when displaying affinity

[tianshilei1992]

Summary

Currently the affinity format string has initial value. When users set
the format via OMP_AFFINITY_FORMAT, it will overwrite the format string. However,
when copying the format, the tailing null is missing. As a result, if the user
format string is shorter than default value, the remaining part in the default
value still makes effort. This bug is not exposed because the test case doesn't
check the end of a string. It only checks whether given output "contains" the
check string.

[tianshilei1992]

Rebased the patch to fix the two failed cases...

[AndreyChurbanov]

LGTM

Thanks

openmp/runtime/src/kmp_safe_c_api.h

 
 #endif // KMP_OS_WINDOWS
 
 // Offer truncated version of strncpy
 static inline void __kmp_strncpy_truncate(char *buffer, size_t buf_size,
                                           char const *src, size_t src_size) {
   if (src_size >= buf_size) {
     src_size = buf_size - 1;
-    KMP_STRNCPY_S(buffer, buf_size, src, src_size);
-    buffer[buf_size - 1] = '\0';
-  } else {
-    KMP_STRNCPY_S(buffer, buf_size, src, src_size);
   }
+  KMP_STRNCPY_S(buffer, buf_size, src, src_size);
+  buffer[src_size] = '\0';
 }
 
 #endif // KMP_SAFE_C_API_H

openmp/runtime/test/affinity/format/simple_env.c

 // RUN: %libomp-compile
 // RUN: env OMP_DISPLAY_AFFINITY=true OMP_AFFINITY_FORMAT='TESTER-ENV: tl:%L tn:%n nt:%N' OMP_NUM_THREADS=8 %libomp-run | %python %S/check.py -c 'CHECK-8' %s
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <omp.h>
 
 int main(int argc, char** argv) {
   #pragma omp parallel
   { }
   #pragma omp parallel
   { }
   return 0;
 }
 
-// CHECK-8: num_threads=8 TESTER-ENV: tl:1 tn:[0-7] nt:8
+// CHECK-8: num_threads=8 TESTER-ENV: tl:1 tn:[0-7] nt:8$