[OpenMP] change shm name to include UID, call unregister_lib on SIGTERM

[terdner]

Summary

With the change to using shared memory, there were a few problems that need to be fixed.

1. The previous filename that was used for SHM only used process id. Given that process is

usually based on 16bit number, this was causing some conflicts on machines. Thus we add
UID to the name to prevent this.

2. It appears under some conditions (SIGTERM, etc) the shared memory files were not getting

cleaned up. Added a call to clean up the shm files under those conditions.

[terdner]

windows doesn't have gituid call so leave windows env variable alone.

[AndreyChurbanov]

LGTM

openmp/runtime/src/kmp.h

 extern void __kmp_internal_end_library(int gtid);
 extern void __kmp_internal_end_thread(int gtid);
 extern void __kmp_internal_end_atexit(void);
 extern void __kmp_internal_end_dtor(void);
 extern void __kmp_internal_end_dest(void *);
 
 extern int __kmp_register_root(int initial_thread);
 extern void __kmp_unregister_root(int gtid);
+extern void __kmp_unregister_library(void); // called by __kmp_internal_end()
 
 extern int __kmp_ignore_mppbeg(void);
 extern int __kmp_ignore_mppend(void);
 
 extern int __kmp_enter_single(int gtid, ident_t *id_ref, int push_ws);
 extern void __kmp_exit_single(int gtid);
 
 extern void __kmp_parallel_deo(int *gtid_ref, int *cid_ref, ident_t *loc_ref);

openmp/runtime/src/kmp_runtime.cpp

 #ifdef USE_LOAD_BALANCE
 static int __kmp_load_balance_nproc(kmp_root_t *root, int set_nproc);
 #endif
 
 static int __kmp_expand_threads(int nNeed);
 #if KMP_OS_WINDOWS
 static int __kmp_unregister_root_other_thread(int gtid);
 #endif
-static void __kmp_unregister_library(void); // called by __kmp_internal_end()
 static void __kmp_reap_thread(kmp_info_t *thread, int is_root);
 kmp_info_t *__kmp_thread_pool_insert_pt = NULL;
 
 /* Calculate the identifier of the current thread */
 /* fast (and somewhat portable) way to get unique identifier of executing
    thread. Returns KMP_GTID_DNE if we haven't been assigned a gtid. */
 int __kmp_get_global_thread_id() {
   int i;

 static char *__kmp_registration_str = NULL;
 // Value to be saved in env var __KMP_REGISTERED_LIB_<pid>.
 
 static inline char *__kmp_reg_status_name() {
   /* On RHEL 3u5 if linked statically, getpid() returns different values in
      each thread. If registration and unregistration go in different threads
      (omp_misc_other_root_exit.cpp test case), the name of registered_lib_env
      env var can not be found, because the name will contain different pid. */
+#if KMP_OS_UNIX && KMP_DYNAMIC_LIB // shared memory is with dynamic library
+  return __kmp_str_format("__KMP_REGISTERED_LIB_%d_%d", (int)getpid(),
+                          (int)getuid());
+#else
   return __kmp_str_format("__KMP_REGISTERED_LIB_%d", (int)getpid());
+#endif
 } // __kmp_reg_status_get
 
 void __kmp_register_library_startup(void) {
 
   char *name = __kmp_reg_status_name(); // Name of the environment variable.
   int done = 0;
   union {
     double dtime;

openmp/runtime/src/z_Linux_util.cpp

#endif
     case SIGSEGV:
 #ifdef SIGSYS
     case SIGSYS:
 #endif
     case SIGTERM:
       if (__kmp_debug_buf) {
         __kmp_dump_debug_buffer();
       }
+      __kmp_unregister_library(); // cleanup shared memory
       KMP_MB(); // Flush all pending memory write invalidates.
       TCW_4(__kmp_global.g.g_abort, signo);
       KMP_MB(); // Flush all pending memory write invalidates.
       TCW_4(__kmp_global.g.g_done, TRUE);
       KMP_MB(); // Flush all pending memory write invalidates.
       break;
     default:
 #ifdef KMP_DEBUG