[OpenMP] libomp minor cleanup

Cleanup changes:
- check value read from file;
- remove dead code;
- make unsigned variable to read hexadecimal number to;
- add debug assertion to check ref count.

Differential Revision: https://reviews.llvm.org/D96893

openmp/runtime/src/kmp_affinity.cpp

@@ -2176,6 +2176,10 @@ static int __kmp_affinity_create_cpuinfo_map(AddrUnsPair **address2os,
     // FIXME - this will match "node_<n> <garbage>"
     unsigned level;
     if (KMP_SSCANF(buf, "node_%u id", &level) == 1) {
+      // validate the input fisrt:
+      if (level > (unsigned)__kmp_xproc) { // level is too big
+        level = __kmp_xproc;
+      }
       if (nodeIdIndex + level >= maxIndex) {
         maxIndex = nodeIdIndex + level;
       }
@@ -4346,8 +4350,6 @@ static void __kmp_aux_affinity_initialize(void) {
         depth = __kmp_affinity_create_hwloc_map(&address2os, &msg_id);
         if (depth == 0) {
           KMP_EXIT_AFF_NONE;
-        } else if (depth < 0 && __kmp_affinity_verbose) {
-          KMP_INFORM(AffIgnoringHwloc, "KMP_AFFINITY");
         }
       } else if (__kmp_affinity_verbose) {
         KMP_INFORM(AffIgnoringHwloc, "KMP_AFFINITY");

openmp/runtime/src/kmp_runtime.cpp

@@ -6487,7 +6487,7 @@ void __kmp_register_library_startup(void) {
       file_name = tail;
       if (tail != NULL) {
         long *flag_addr = 0;
-        long flag_val = 0;
+        unsigned long flag_val = 0;
         KMP_SSCANF(flag_addr_str, "%p", RCAST(void **, &flag_addr));
         KMP_SSCANF(flag_val_str, "%lx", &flag_val);
         if (flag_addr != 0 && flag_val != 0 && strcmp(file_name, "") != 0) {

openmp/runtime/src/kmp_taskdeps.h

@@ -23,6 +23,7 @@ static inline void __kmp_node_deref(kmp_info_t *thread, kmp_depnode_t *node) {
     return;
 
   kmp_int32 n = KMP_ATOMIC_DEC(&node->dn.nrefs) - 1;
+  KMP_DEBUG_ASSERT(n >= 0);
   if (n == 0) {
     KMP_ASSERT(node->dn.nrefs == 0);
 #if USE_FAST_MEMORY