示例#1
0
// Remove unreferenced symbols from the symbol table
// This is done late during GC.
void SymbolTable::unlink() {
  int removed = 0;
  int total = 0;
  size_t memory_total = 0;
  for (int i = 0; i < the_table()->table_size(); ++i) {
    HashtableEntry<Symbol*, mtSymbol>** p = the_table()->bucket_addr(i);
    HashtableEntry<Symbol*, mtSymbol>* entry = the_table()->bucket(i);
    while (entry != NULL) {
      // Shared entries are normally at the end of the bucket and if we run into
      // a shared entry, then there is nothing more to remove. However, if we
      // have rehashed the table, then the shared entries are no longer at the
      // end of the bucket.
      if (entry->is_shared() && !use_alternate_hashcode()) {
        break;
      }
      Symbol* s = entry->literal();
      memory_total += s->object_size();
      total++;
      assert(s != NULL, "just checking");
      // If reference count is zero, remove.
      if (s->refcount() == 0) {
        assert(!entry->is_shared(), "shared entries should be kept live");
        delete s;
        removed++;
        *p = entry->next();
        the_table()->free_entry(entry);
      } else {
        p = entry->next_addr();
      }
      // get next entry
      entry = (HashtableEntry<Symbol*, mtSymbol>*)HashtableEntry<Symbol*, mtSymbol>::make_ptr(*p);
    }
  }
  symbols_removed += removed;
  symbols_counted += total;
  // Exclude printing for normal PrintGCDetails because people parse
  // this output.
  if (PrintGCDetails && Verbose && WizardMode) {
    gclog_or_tty->print(" [Symbols=%d size=" SIZE_FORMAT "K] ", total,
                        (memory_total*HeapWordSize)/1024);
  }
}