gcc/spellcheck-tree.c

   1 /* Find near-matches for identifiers.
   2    Copyright (C) 2015-2017 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 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "tree.h"
  25 #include "cpplib.h"
  26 #include "spellcheck-tree.h"
  27 #include "selftest.h"
  28 #include "stringpool.h"
  29
  30 /* Calculate Levenshtein distance between two identifiers.  */
  31
  32 edit_distance_t
  33 levenshtein_distance (tree ident_s, tree ident_t)
  34 {
  35   gcc_assert (TREE_CODE (ident_s) == IDENTIFIER_NODE);
  36   gcc_assert (TREE_CODE (ident_t) == IDENTIFIER_NODE);
  37
  38   return levenshtein_distance (IDENTIFIER_POINTER (ident_s),
  39                                IDENTIFIER_LENGTH (ident_s),
  40                                IDENTIFIER_POINTER (ident_t),
  41                                IDENTIFIER_LENGTH (ident_t));
  42 }
  43
  44 /* Given TARGET, an identifier, and CANDIDATES, a vec of identifiers,
  45    determine which element within CANDIDATES has the lowest edit
  46    distance to TARGET.  If there are multiple elements with the
  47    same minimal distance, the first in the vector wins.
  48
  49    If more than half of the letters were misspelled, the suggestion is
  50    likely to be meaningless, so return NULL_TREE for this case.  */
  51
  52 tree
  53 find_closest_identifier (tree target, const auto_vec<tree> *candidates)
  54 {
  55   gcc_assert (TREE_CODE (target) == IDENTIFIER_NODE);
  56
  57   best_match<tree, tree> bm (target);
  58   int i;
  59   tree identifier;
  60   FOR_EACH_VEC_ELT (*candidates, i, identifier)
  61     {
  62       gcc_assert (TREE_CODE (identifier) == IDENTIFIER_NODE);
  63       bm.consider (identifier);
  64     }
  65
  66   return bm.get_best_meaningful_candidate ();
  67 }
  68
  69 /* A callback for cpp_forall_identifiers, for use by best_macro_match's ctor.
  70    Process HASHNODE and update the best_macro_match instance pointed to be
  71    USER_DATA.  */
  72
  73 static int
  74 find_closest_macro_cpp_cb (cpp_reader *, cpp_hashnode *hashnode,
  75                            void *user_data)
  76 {
  77   if (hashnode->type != NT_MACRO)
  78     return 1;
  79
  80   best_macro_match *bmm = (best_macro_match *)user_data;
  81   bmm->consider (hashnode);
  82
  83   /* Keep iterating.  */
  84   return 1;
  85 }
  86
  87 /* Constructor for best_macro_match.
  88    Use find_closest_macro_cpp_cb to find the closest matching macro to
  89    NAME within distance < best_distance_so_far. */
  90
  91 best_macro_match::best_macro_match (tree goal,
  92                                     edit_distance_t best_distance_so_far,
  93                                     cpp_reader *reader)
  94 : best_match <goal_t, candidate_t> (goal, best_distance_so_far)
  95 {
  96   cpp_forall_identifiers (reader, find_closest_macro_cpp_cb, this);
  97 }
  98
  99 #if CHECKING_P
 100
 101 namespace selftest {
 102
 103 /* Selftests.  */
 104
 105 /* Verify that find_closest_identifier is sane.  */
 106
 107 static void
 108 test_find_closest_identifier ()
 109 {
 110   auto_vec<tree> candidates;
 111
 112   /* Verify that it can handle an empty vec.  */
 113   ASSERT_EQ (NULL, find_closest_identifier (get_identifier (""), &candidates));
 114
 115   /* Verify that it works sanely for non-empty vecs.  */
 116   tree apple = get_identifier ("apple");
 117   tree banana = get_identifier ("banana");
 118   tree cherry = get_identifier ("cherry");
 119   candidates.safe_push (apple);
 120   candidates.safe_push (banana);
 121   candidates.safe_push (cherry);
 122
 123   ASSERT_EQ (apple, find_closest_identifier (get_identifier ("app"),
 124                                              &candidates));
 125   ASSERT_EQ (banana, find_closest_identifier (get_identifier ("banyan"),
 126                                               &candidates));;
 127   ASSERT_EQ (cherry, find_closest_identifier (get_identifier ("berry"),
 128                                               &candidates));
 129   ASSERT_EQ (NULL,
 130              find_closest_identifier (get_identifier ("not like the others"),
 131                                       &candidates));
 132 }
 133
 134 /* Run all of the selftests within this file.  */
 135
 136 void
 137 spellcheck_tree_c_tests ()
 138 {
 139   test_find_closest_identifier ();
 140 }
 141
 142 } // namespace selftest
 143
 144 #endif /* #if CHECKING_P */