libcpp/identifiers.c

   1 /* Hash tables for the CPP library.
   2    Copyright (C) 1986-2017 Free Software Foundation, Inc.
   3    Written by Per Bothner, 1994.
   4    Based on CCCP program by Paul Rubin, June 1986
   5    Adapted to ANSI C, Richard Stallman, Jan 1987
   6
   7 This program is free software; you can redistribute it and/or modify it
   8 under the terms of the GNU General Public License as published by the
   9 Free Software Foundation; either version 3, or (at your option) any
  10 later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with this program; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.
  20
  21  In other words, you are welcome to use, share and improve this program.
  22  You are forbidden to forbid anyone else to use, share and improve
  23  what you give them.   Help stamp out software-hoarding!  */
  24
  25 #include "config.h"
  26 #include "system.h"
  27 #include "cpplib.h"
  28 #include "internal.h"
  29
  30 static hashnode alloc_node (cpp_hash_table *);
  31
  32 /* Return an identifier node for hashtable.c.  Used by cpplib except
  33    when integrated with the C front ends.  */
  34 static hashnode
  35 alloc_node (cpp_hash_table *table)
  36 {
  37   cpp_hashnode *node;
  38
  39   node = XOBNEW (&table->pfile->hash_ob, cpp_hashnode);
  40   memset (node, 0, sizeof (cpp_hashnode));
  41   return HT_NODE (node);
  42 }
  43
  44 /* Set up the identifier hash table.  Use TABLE if non-null, otherwise
  45    create our own.  */
  46 void
  47 _cpp_init_hashtable (cpp_reader *pfile, cpp_hash_table *table)
  48 {
  49   struct spec_nodes *s;
  50
  51   if (table == NULL)
  52     {
  53       pfile->our_hashtable = 1;
  54       table = ht_create (13);   /* 8K (=2^13) entries.  */
  55       table->alloc_node = alloc_node;
  56
  57       obstack_specify_allocation (&pfile->hash_ob, 0, 0, xmalloc, free);
  58     }
  59
  60   table->pfile = pfile;
  61   pfile->hash_table = table;
  62
  63   /* Now we can initialize things that use the hash table.  */
  64   _cpp_init_directives (pfile);
  65   _cpp_init_internal_pragmas (pfile);
  66
  67   s = &pfile->spec_nodes;
  68   s->n_defined          = cpp_lookup (pfile, DSC("defined"));
  69   s->n_true             = cpp_lookup (pfile, DSC("true"));
  70   s->n_false            = cpp_lookup (pfile, DSC("false"));
  71   s->n__VA_ARGS__       = cpp_lookup (pfile, DSC("__VA_ARGS__"));
  72   s->n__VA_ARGS__->flags |= NODE_DIAGNOSTIC;
  73   s->n__VA_OPT__        = cpp_lookup (pfile, DSC("__VA_OPT__"));
  74   s->n__VA_OPT__->flags |= NODE_DIAGNOSTIC;
  75   s->n__has_include__   = cpp_lookup (pfile, DSC("__has_include__"));
  76   s->n__has_include_next__ = cpp_lookup (pfile, DSC("__has_include_next__"));
  77 }
  78
  79 /* Tear down the identifier hash table.  */
  80 void
  81 _cpp_destroy_hashtable (cpp_reader *pfile)
  82 {
  83   if (pfile->our_hashtable)
  84     {
  85       ht_destroy (pfile->hash_table);
  86       obstack_free (&pfile->hash_ob, 0);
  87     }
  88 }
  89
  90 /* Returns the hash entry for the STR of length LEN, creating one
  91    if necessary.  */
  92 cpp_hashnode *
  93 cpp_lookup (cpp_reader *pfile, const unsigned char *str, unsigned int len)
  94 {
  95   /* ht_lookup cannot return NULL.  */
  96   return CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_ALLOC));
  97 }
  98
  99 /* Determine whether the str STR, of length LEN, is a defined macro.  */
 100 int
 101 cpp_defined (cpp_reader *pfile, const unsigned char *str, int len)
 102 {
 103   cpp_hashnode *node;
 104
 105   node = CPP_HASHNODE (ht_lookup (pfile->hash_table, str, len, HT_NO_INSERT));
 106
 107   /* If it's of type NT_MACRO, it cannot be poisoned.  */
 108   return node && node->type == NT_MACRO;
 109 }
 110
 111 /* We don't need a proxy since the hash table's identifier comes first
 112    in cpp_hashnode.  However, in case this is ever changed, we have a
 113    static assertion for it.  */
 114 extern char proxy_assertion_broken[offsetof (struct cpp_hashnode, ident) == 0 ? 1 : -1];
 115
 116 /* For all nodes in the hashtable, callback CB with parameters PFILE,
 117    the node, and V.  */
 118 void
 119 cpp_forall_identifiers (cpp_reader *pfile, cpp_cb cb, void *v)
 120 {
 121   ht_forall (pfile->hash_table, (ht_cb) cb, v);
 122 }