gcc/hash-set.h

   1 /* A type-safe hash set.
   2    Copyright (C) 2014-2023 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         {
  62           new (e) Key (k);
  63           // Catch attempts to insert e.g. a NULL pointer.
  64           gcc_checking_assert (!Traits::is_empty (*e)
  65                                && !Traits::is_deleted (*e));
  66         }
  67
  68       return existed;
  69     }
  70
  71   /* if the passed in key is in the map return its value otherwise NULL.  */
  72
  73   bool contains (const Key &k)
  74     {
  75       if (Lazy)
  76         return (m_table.find_slot_with_hash (k, Traits::hash (k), NO_INSERT)
  77                 != NULL);
  78       Key &e = m_table.find_with_hash (k, Traits::hash (k));
  79       return !Traits::is_empty (e);
  80     }
  81
  82   void remove (const Key &k)
  83     {
  84       m_table.remove_elt_with_hash (k, Traits::hash (k));
  85     }
  86
  87   /* Call the call back on each pair of key and value with the passed in
  88      arg.  */
  89
  90   template<typename Arg, bool (*f)(const typename Traits::value_type &, Arg)>
  91   void traverse (Arg a) const
  92     {
  93       for (typename hash_table<Traits, Lazy>::iterator iter = m_table.begin ();
  94            iter != m_table.end (); ++iter)
  95         f (*iter, a);
  96     }
  97
  98   /* Return the number of elements in the set.  */
  99
 100   size_t elements () const { return m_table.elements (); }
 101
 102   /* Clear the hash table.  */
 103
 104   void empty () { m_table.empty (); }
 105
 106   /* Return true when there are no elements in this hash set.  */
 107   bool is_empty () const { return m_table.is_empty (); }
 108
 109   class iterator
 110   {
 111   public:
 112     explicit iterator (const typename hash_table<Traits,
 113                                                  Lazy>::iterator &iter) :
 114       m_iter (iter) {}
 115
 116     iterator &operator++ ()
 117       {
 118         ++m_iter;
 119         return *this;
 120       }
 121
 122     Key
 123     operator* ()
 124       {
 125         return *m_iter;
 126       }
 127
 128     bool
 129     operator != (const iterator &other) const
 130       {
 131         return m_iter != other.m_iter;
 132       }
 133
 134   private:
 135     typename hash_table<Traits, Lazy>::iterator m_iter;
 136   };
 137
 138   /* Standard iterator retrieval methods.  */
 139
 140   iterator begin () const { return iterator (m_table.begin ()); }
 141   iterator end () const { return iterator (m_table.end ()); }
 142
 143
 144 private:
 145
 146   template<typename T, typename U>
 147   friend void gt_ggc_mx (hash_set<T, false, U> *);
 148   template<typename T, typename U>
 149   friend void gt_pch_nx (hash_set<T, false, U> *);
 150   template<typename T, typename U>
 151   friend void gt_pch_nx (hash_set<T, false, U> *, gt_pointer_operator, void *);
 152
 153   hash_table<Traits, Lazy> m_table;
 154 };
 155
 156 /* Generic hash_set<TYPE> debug helper.
 157
 158    This needs to be instantiated for each hash_set<TYPE> used throughout
 159    the compiler like this:
 160
 161     DEFINE_DEBUG_HASH_SET (TYPE)
 162
 163    The reason we have a debug_helper() is because GDB can't
 164    disambiguate a plain call to debug(some_hash), and it must be called
 165    like debug<TYPE>(some_hash).  */
 166 template<typename T>
 167 void
 168 debug_helper (hash_set<T> &ref)
 169 {
 170   for (typename hash_set<T>::iterator it = ref.begin ();
 171        it != ref.end (); ++it)
 172     {
 173       debug_slim (*it);
 174       fputc ('\n', stderr);
 175     }
 176 }
 177
 178 #define DEFINE_DEBUG_HASH_SET(T) \
 179   template void debug_helper (hash_set<T> &);           \
 180   DEBUG_FUNCTION void                                   \
 181   debug (hash_set<T> &ref)                              \
 182   {                                                     \
 183     debug_helper <T> (ref);                             \
 184   }                                                     \
 185   DEBUG_FUNCTION void                                   \
 186   debug (hash_set<T> *ptr)                              \
 187   {                                                     \
 188     if (ptr)                                            \
 189       debug (*ptr);                                     \
 190     else                                                \
 191       fprintf (stderr, "<nil>\n");                      \
 192   }
 193
 194 /* ggc marking routines.  */
 195
 196 template<typename K, typename H>
 197 inline void
 198 gt_ggc_mx (hash_set<K, false, H> *h)
 199 {
 200   gt_ggc_mx (&h->m_table);
 201 }
 202
 203 template<typename K, typename H>
 204 inline void
 205 gt_pch_nx (hash_set<K, false, H> *h)
 206 {
 207   gt_pch_nx (&h->m_table);
 208 }
 209
 210 template<typename K, typename H>
 211 inline void
 212 gt_pch_nx (hash_set<K, false, H> *h, gt_pointer_operator op, void *cookie)
 213 {
 214   op (&h->m_table.m_entries, NULL, cookie);
 215 }
 216
 217 #endif