sentinel: fix sentinel to proc_name conversion

converting an opal_process_name_t means the loss of one bit,
it was decided to restrict the local job id to 15 bits, so the
useful information of an opal_process_name_t can fit in 63 bits.

Author: ggouaillardet

ompi/proc/proc.h

@@ -369,15 +369,42 @@ static inline bool ompi_proc_is_sentinel (ompi_proc_t *proc)
     return (intptr_t) proc & 0x1;
 }
 
+/*
+ * we assume an ompi_proc_t is at least aligned on two bytes,
+ * so if the LSB of a pointer to an ompi_proc_t is 1, we have to handle
+ * this pointer as a sentinel instead of a pointer.
+ * a sentinel can be seen as a 64 bits array with the following format :
+ * - bit  0     : 1
+ * - bits 1-15  : local jobid
+ * - bits 16-31 : job family
+ * - bits 32-63 : vpid
+ */
 static inline uintptr_t ompi_proc_name_to_sentinel (opal_process_name_t name)
 {
-  return (*((uintptr_t *) &name) << 1) | 0x1;
+    uintptr_t tmp, sentinel = 0x1;
+    /* local jobid must fit in 15 bits */
+    assert(! (ORTE_LOCAL_JOBID(name.jobid) & 0x8000));
+    tmp = (uintptr_t)ORTE_LOCAL_JOBID(name.jobid);
+    sentinel |= ((tmp << 1) & 0xfffe);
+    tmp = (uintptr_t)ORTE_JOB_FAMILY(name.jobid);
+    sentinel |= ((tmp << 16) & 0xffff0000);
+    tmp = (uintptr_t)name.vpid;
+    sentinel |= ((tmp << 32) & 0xffffffff00000000);
+    return sentinel;
 }
 
 static inline opal_process_name_t ompi_proc_sentinel_to_name (uintptr_t sentinel)
 {
-  sentinel >>= 1;
-  return *((opal_process_name_t *) &sentinel);
+  opal_process_name_t name;
+  uint16_t local, family;
+  uint32_t vpid;
+  assert(sentinel & 0x1);
+  local = (sentinel >> 1) & 0x7fff;
+  family = (sentinel >> 16) & 0xffff;
+  vpid = (sentinel >> 32) & 0xffffffff;
+  name.jobid = ORTE_CONSTRUCT_JOBID(family,local);
+  name.vpid = vpid;
+  return name;
 }
 
 END_C_DECLS

orte/util/name_fns.h

@@ -97,6 +97,9 @@ ORTE_DECLSPEC char *orte_pretty_print_timing(int64_t secs, int64_t usecs);
 #define ORTE_CONSTRUCT_LOCAL_JOBID(local, job) \
     ( ((local) & 0xffff0000) | ((job) & 0x0000ffff) )
 
+#define ORTE_CONSTRUCT_JOBID(family, local) \
+    ORTE_CONSTRUCT_LOCAL_JOBID(ORTE_CONSTRUCT_JOB_FAMILY(family), local)
+
 /* a macro for identifying that a proc is a daemon */
 #define ORTE_JOBID_IS_DAEMON(n)  \
     !((n) & 0x0000ffff)