gcc/hash-set.h

   1 /* A type-safe hash set.
   2    Copyright (C) 2014-2020 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #ifndef hash_set_h
  22 #define hash_set_h
  23
  24 /* Class hash_set is a hash-value based container for objects of
  25    KeyId type.
  26    KeyId may be a non-trivial (non-POD) type provided a suitabe Traits
  27    class.  Default Traits specializations are provided for basic types
  28    such as integers, pointers, and std::pair.  Inserted elements are
  29    value-initialized either to zero for POD types or by invoking their
  30    default ctor.  Removed elements are destroyed by invoking their dtor.
  31    On hash_set destruction all elements are removed.  Objects of
  32    hash_set type are copy-constructible but not assignable.  */
  33
  34 template<typename KeyId, bool Lazy = false,
  35          typename Traits = default_hash_traits<KeyId> >
  36 class hash_set
  37 {
  38 public:
  39   typedef typename Traits::value_type Key;
  40   explicit hash_set (size_t n = 13, bool ggc = false CXX_MEM_STAT_INFO)
  41     : m_table (n, ggc, true, GATHER_STATISTICS, HASH_SET_ORIGIN PASS_MEM_STAT) {}
  42
  43   /* Create a hash_set in gc memory with space for at least n elements.  */
  44
  45   static hash_set *
  46   create_ggc (size_t n)
  47     {
  48       hash_set *set = ggc_alloc<hash_set> ();
  49       new (set) hash_set (n, true);
  50       return set;
  51     }
  52
  53   /* If key k isn't already in the map add it to the map, and
  54      return false.  Otherwise return true.  */
  55
  56   bool add (const Key &k)
  57     {
  58       Key *e = m_table.find_slot_with_hash (k, Traits::hash (k), INSERT);
  59       bool existed = !Traits::is_empty (*e);
  60       if (!existed)
  61         new (e) Key (k);
  62
  63       return existed;
  64     }
  65
  66   /* if the passed in key is in the map return its value otherwise NULL.  */
  67
  68   bool contains (const Key &k)
  69     {
  70       if (Lazy)
  71         return (m_table.find_slot_with_hash (k, Traits::hash (k), NO_INSERT)
  72                 != NULL);
  73       Key &e = m_table.find_with_hash (k, Traits::hash (k));
  74       return !Traits::is_empty (e);
  75     }
  76
  77   void remove (const Key &k)
  78     {
  79       m_table.remove_elt_with_hash (k, Traits::hash (k));
  80     }
  81
  82   /* Call the call back on each pair of key and value with the passed in
  83      arg.  */
  84
  85   template<typename Arg, bool (*f)(const typename Traits::value_type &, Arg)>
  86   void traverse (Arg a) const
  87     {
  88       for (typename hash_table<Traits, Lazy>::iterator iter = m_table.begin ();
  89            iter != m_table.end (); ++iter)
  90         f (*iter, a);
  91     }
  92
  93   /* Return the number of elements in the set.  */
  94
  95   size_t elements () const { return m_table.elements (); }
  96
  97   /* Clear the hash table.  */
  98
  99   void empty () { m_table.empty (); }
 100
 101   /* Return true when there are no elements in this hash set.  */
 102   bool is_empty () const { return m_table.is_empty (); }
 103
 104   class iterator
 105   {
 106   public:
 107     explicit iterator (const typename hash_table<Traits,
 108                                                  Lazy>::iterator &iter) :
 109       m_iter (iter) {}
 110
 111     iterator &operator++ ()
 112       {
 113         ++m_iter;
 114         return *this;
 115       }
 116
 117     Key
 118     operator* ()
 119       {
 120         return *m_iter;
 121       }
 122
 123     bool
 124     operator != (const iterator &other) const
 125       {
 126         return m_iter != other.m_iter;
 127       }
 128
 129   private:
 130     typename hash_table<Traits, Lazy>::iterator m_iter;
 131   };
 132
 133   /* Standard iterator retrieval methods.  */
 134
 135   iterator begin () const { return iterator (m_table.begin ()); }
 136   iterator end () const { return iterator (m_table.end ()); }
 137
 138
 139 private:
 140
 141   template<typename T, typename U>
 142   friend void gt_ggc_mx (hash_set<T, false, U> *);
 143   template<typename T, typename U>
 144   friend void gt_pch_nx (hash_set<T, false, U> *);
 145   template<typename T, typename U>
 146   friend void gt_pch_nx (hash_set<T, false, U> *, gt_pointer_operator, void *);
 147
 148   hash_table<Traits, Lazy> m_table;
 149 };
 150
 151 /* Generic hash_set<TYPE> debug helper.
 152
 153    This needs to be instantiated for each hash_set<TYPE> used throughout
 154    the compiler like this:
 155
 156     DEFINE_DEBUG_HASH_SET (TYPE)
 157
 158    The reason we have a debug_helper() is because GDB can't
 159    disambiguate a plain call to debug(some_hash), and it must be called
 160    like debug<TYPE>(some_hash).  */
 161 template<typename T>
 162 void
 163 debug_helper (hash_set<T> &ref)
 164 {
 165   for (typename hash_set<T>::iterator it = ref.begin ();
 166        it != ref.end (); ++it)
 167     {
 168       debug_slim (*it);
 169       fputc ('\n', stderr);
 170     }
 171 }
 172
 173 #define DEFINE_DEBUG_HASH_SET(T) \
 174   template void debug_helper (hash_set<T> &);           \
 175   DEBUG_FUNCTION void                                   \
 176   debug (hash_set<T> &ref)                              \
 177   {                                                     \
 178     debug_helper <T> (ref);                             \
 179   }                                                     \
 180   DEBUG_FUNCTION void                                   \
 181   debug (hash_set<T> *ptr)                              \
 182   {                                                     \
 183     if (ptr)                                            \
 184       debug (*ptr);                                     \
 185     else                                                \
 186       fprintf (stderr, "<nil>\n");                      \
 187   }
 188
 189 /* ggc marking routines.  */
 190
 191 template<typename K, typename H>
 192 static inline void
 193 gt_ggc_mx (hash_set<K, false, H> *h)
 194 {
 195   gt_ggc_mx (&h->m_table);
 196 }
 197
 198 template<typename K, typename H>
 199 static inline void
 200 gt_pch_nx (hash_set<K, false, H> *h)
 201 {
 202   gt_pch_nx (&h->m_table);
 203 }
 204
 205 template<typename K, typename H>
 206 static inline void
 207 gt_pch_nx (hash_set<K, false, H> *h, gt_pointer_operator op, void *cookie)
 208 {
 209   op (&h->m_table.m_entries, cookie);
 210 }
 211
 212 #endif