void checkUnload()

in rts/CheckUnload.c [277:363]
67 lines of code
11 McCabe index (conditional complexity)

void checkUnload (StgClosure *static_objects)
{
  uint32_t g, n;
  HashTable *addrs;
  StgClosure* p;
  const StgInfoTable *info;
  ObjectCode *oc, *prev, *next;
  gen_workspace *ws;
  StgClosure* link;

  if (unloaded_objects == NULL) return;

  ACQUIRE_LOCK(&linker_unloaded_mutex);

  // Mark every unloadable object as unreferenced initially
  for (oc = unloaded_objects; oc; oc = oc->next) {
      IF_DEBUG(linker, debugBelch("Checking whether to unload %" PATH_FMT "\n",
                                  oc->fileName));
      oc->referenced = false;
  }

  addrs = allocHashTable();

  for (p = static_objects; p != END_OF_STATIC_OBJECT_LIST; p = link) {
      p = UNTAG_STATIC_LIST_PTR(p);
      checkAddress(addrs, p);
      info = get_itbl(p);
      link = *STATIC_LINK(info, p);
  }

  // CAFs on revertible_caf_list are not on static_objects
  for (p = (StgClosure*)revertible_caf_list;
       p != END_OF_CAF_LIST;
       p = ((StgIndStatic *)p)->static_link) {
      p = UNTAG_STATIC_LIST_PTR(p);
      checkAddress(addrs, p);
  }

  for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
      searchHeapBlocks (addrs, generations[g].blocks);
      searchHeapBlocks (addrs, generations[g].large_objects);

      for (n = 0; n < n_capabilities; n++) {
          ws = &gc_threads[n]->gens[g];
          searchHeapBlocks(addrs, ws->todo_bd);
          searchHeapBlocks(addrs, ws->part_list);
          searchHeapBlocks(addrs, ws->scavd_list);
      }
  }

#if defined(PROFILING)
  /* Traverse the cost centre tree, calling checkAddress on each CCS/CC */
  searchCostCentres(addrs, CCS_MAIN);

  /* Also check each cost centre in the CC_LIST */
  CostCentre *cc;
  for (cc = CC_LIST; cc != NULL; cc = cc->link) {
      checkAddress(addrs, cc);
  }
#endif /* PROFILING */

  // Look through the unloadable objects, and any object that is still
  // marked as unreferenced can be physically unloaded, because we
  // have no references to it.
  prev = NULL;
  for (oc = unloaded_objects; oc; oc = next) {
      next = oc->next;
      if (oc->referenced == 0) {
          if (prev == NULL) {
              unloaded_objects = oc->next;
          } else {
              prev->next = oc->next;
          }
          IF_DEBUG(linker, debugBelch("Unloading object file %" PATH_FMT "\n",
                                      oc->fileName));
          freeObjectCode(oc);
      } else {
          IF_DEBUG(linker, debugBelch("Object file still in use: %"
                                      PATH_FMT "\n", oc->fileName));
          prev = oc;
      }
  }

  freeHashTable(addrs, NULL);

  RELEASE_LOCK(&linker_unloaded_mutex);
}