LCOV - code coverage report
Current view: top level - gcc - spellcheck.h (source / functions) Hit Total Coverage
Test: gcc.info Lines: 38 40 95.0 %
Date: 2020-03-28 11:57:23 Functions: 12 12 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 0 0 -

           Branch data     Line data    Source code
       1                 :            : /* Find near-matches for strings and identifiers.
       2                 :            :    Copyright (C) 2015-2020 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                 :            : #ifndef GCC_SPELLCHECK_H
      21                 :            : #define GCC_SPELLCHECK_H
      22                 :            : 
      23                 :            : typedef unsigned int edit_distance_t;
      24                 :            : const edit_distance_t MAX_EDIT_DISTANCE = UINT_MAX;
      25                 :            : 
      26                 :            : /* spellcheck.c  */
      27                 :            : extern edit_distance_t
      28                 :            : get_edit_distance (const char *s, int len_s,
      29                 :            :                    const char *t, int len_t);
      30                 :            : 
      31                 :            : extern edit_distance_t
      32                 :            : get_edit_distance (const char *s, const char *t);
      33                 :            : 
      34                 :            : extern const char *
      35                 :            : find_closest_string (const char *target,
      36                 :            :                      const auto_vec<const char *> *candidates);
      37                 :            : 
      38                 :            : /* A traits class for describing a string-like type usable by
      39                 :            :    class best_match.
      40                 :            :    Specializations should provide the implementations of the following:
      41                 :            : 
      42                 :            :      static size_t get_length (TYPE);
      43                 :            :      static const char *get_string (TYPE);
      44                 :            : 
      45                 :            :    get_string should return a non-NULL ptr, which does not need to be
      46                 :            :    0-terminated.  */
      47                 :            : 
      48                 :            : template <typename TYPE>
      49                 :            : struct edit_distance_traits {};
      50                 :            : 
      51                 :            : /* Specialization of edit_distance_traits for C-style strings.  */
      52                 :            : 
      53                 :            : template <>
      54                 :            : struct edit_distance_traits<const char *>
      55                 :            : {
      56                 :    2939594 :   static size_t get_length (const char *str)
      57                 :            :   {
      58                 :    2939594 :     gcc_assert (str);
      59                 :    2939594 :     return strlen (str);
      60                 :            :   }
      61                 :            : 
      62                 :     864772 :   static const char *get_string (const char *str)
      63                 :            :   {
      64                 :          0 :     gcc_assert (str);
      65                 :     864772 :     return str;
      66                 :            :   }
      67                 :            : };
      68                 :            : 
      69                 :            : extern edit_distance_t get_edit_distance_cutoff (size_t goal_len,
      70                 :            :                                                  size_t candidate_len);
      71                 :            : 
      72                 :            : /* A type for use when determining the best match against a string,
      73                 :            :    expressed as a template so that we can match against various
      74                 :            :    string-like types (const char *, frontend identifiers, and preprocessor
      75                 :            :    macros).
      76                 :            : 
      77                 :            :    This type accumulates the best possible match against GOAL_TYPE for
      78                 :            :    a sequence of elements of CANDIDATE_TYPE, whilst minimizing the
      79                 :            :    number of calls to get_edit_distance and to
      80                 :            :    edit_distance_traits<T>::get_length.  */
      81                 :            : 
      82                 :            : template <typename GOAL_TYPE, typename CANDIDATE_TYPE>
      83                 :            : class best_match
      84                 :            : {
      85                 :            :  public:
      86                 :            :   typedef GOAL_TYPE goal_t;
      87                 :            :   typedef CANDIDATE_TYPE candidate_t;
      88                 :            :   typedef edit_distance_traits<goal_t> goal_traits;
      89                 :            :   typedef edit_distance_traits<candidate_t> candidate_traits;
      90                 :            : 
      91                 :            :   /* Constructor.  */
      92                 :            : 
      93                 :      11996 :   best_match (GOAL_TYPE goal,
      94                 :            :               edit_distance_t best_distance_so_far = MAX_EDIT_DISTANCE)
      95                 :      11996 :   : m_goal (goal_traits::get_string (goal)),
      96                 :      11996 :     m_goal_len (goal_traits::get_length (goal)),
      97                 :            :     m_best_candidate (NULL),
      98                 :      11996 :     m_best_distance (best_distance_so_far)
      99                 :        416 :   {}
     100                 :            : 
     101                 :            :   /* Compare the edit distance between CANDIDATE and m_goal,
     102                 :            :      and if it's the best so far, record it.  */
     103                 :            : 
     104                 :    5226607 :   void consider (candidate_t candidate)
     105                 :            :   {
     106                 :    5226607 :     size_t candidate_len = candidate_traits::get_length (candidate);
     107                 :            : 
     108                 :            :     /* Calculate a lower bound on the candidate's distance to the goal,
     109                 :            :        based on the difference in lengths; it will require at least
     110                 :            :        this many insertions/deletions.  */
     111                 :    5226607 :     edit_distance_t min_candidate_distance
     112                 :    5226607 :       = abs ((ssize_t)candidate_len - (ssize_t)m_goal_len);
     113                 :            : 
     114                 :            :     /* If the candidate's length is sufficiently different to that
     115                 :            :        of the goal string, then the number of insertions/deletions
     116                 :            :        may be >= the best distance so far.  If so, we can reject
     117                 :            :        the candidate immediately without needing to compute
     118                 :            :        the exact distance, since it won't be an improvement.  */
     119                 :    5226607 :     if (min_candidate_distance >= m_best_distance)
     120                 :            :       return;
     121                 :            : 
     122                 :            :     /* If the candidate will be unable to beat the criterion in
     123                 :            :        get_best_meaningful_candidate, reject it without computing
     124                 :            :        the exact distance.  */
     125                 :    4917894 :     edit_distance_t cutoff = get_cutoff (candidate_len);
     126                 :    2458947 :     if (min_candidate_distance > cutoff)
     127                 :            :       return;
     128                 :            : 
     129                 :            :     /* Otherwise, compute the distance and see if the candidate
     130                 :            :        has beaten the previous best value.  */
     131                 :            :     edit_distance_t dist
     132                 :    1968175 :       = get_edit_distance (m_goal, m_goal_len,
     133                 :            :                            candidate_traits::get_string (candidate),
     134                 :            :                            candidate_len);
     135                 :    1968175 :     if (dist < m_best_distance)
     136                 :            :       {
     137                 :      11704 :         m_best_distance = dist;
     138                 :      11704 :         m_best_candidate = candidate;
     139                 :      11704 :         m_best_candidate_len = candidate_len;
     140                 :            :       }
     141                 :            :   }
     142                 :            : 
     143                 :            :   /* Assuming that BEST_CANDIDATE is known to be better than
     144                 :            :      m_best_candidate, update (without recomputing the edit distance to
     145                 :            :      the goal).  */
     146                 :            : 
     147                 :          6 :   void set_best_so_far (CANDIDATE_TYPE best_candidate,
     148                 :            :                         edit_distance_t best_distance,
     149                 :            :                         size_t best_candidate_len)
     150                 :            :   {
     151                 :          0 :     gcc_assert (best_distance < m_best_distance);
     152                 :          6 :     m_best_candidate = best_candidate;
     153                 :          6 :     m_best_distance = best_distance;
     154                 :          6 :     m_best_candidate_len = best_candidate_len;
     155                 :          6 :   }
     156                 :            : 
     157                 :            :   /* Generate the maximum edit distance for which we consider a suggestion
     158                 :            :      to be meaningful, given a candidate of length CANDIDATE_LEN.  */
     159                 :            : 
     160                 :    2465574 :   edit_distance_t get_cutoff (size_t candidate_len) const
     161                 :            :   {
     162                 :    2458947 :     return ::get_edit_distance_cutoff (m_goal_len, candidate_len);
     163                 :            :   }
     164                 :            : 
     165                 :            :   /* Get the best candidate so far, but applying a filter to ensure
     166                 :            :      that we return NULL if none of the candidates are close to the goal,
     167                 :            :      to avoid offering nonsensical suggestions to the user.  */
     168                 :            : 
     169                 :      11943 :   candidate_t get_best_meaningful_candidate () const
     170                 :            :   {
     171                 :            :     /* If the edit distance is too high, the suggestion is likely to be
     172                 :            :        meaningless.  */
     173                 :      11943 :     if (m_best_candidate)
     174                 :            :       {
     175                 :       6627 :         edit_distance_t cutoff = get_cutoff (m_best_candidate_len);
     176                 :       6627 :         if (m_best_distance > cutoff)
     177                 :            :           return NULL;
     178                 :            :     }
     179                 :            : 
     180                 :            :     /* If the goal string somehow makes it into the candidate list, offering
     181                 :            :        it as a suggestion will be nonsensical e.g.
     182                 :            :          'constexpr' does not name a type; did you mean 'constexpr'?
     183                 :            :        Ultimately such suggestions are due to bugs in constructing the
     184                 :            :        candidate list, but as a band-aid, do not offer suggestions for
     185                 :            :        distance == 0 (where candidate == goal).  */
     186                 :       6441 :     if (m_best_distance == 0)
     187                 :            :       return NULL;
     188                 :            : 
     189                 :       6181 :     return m_best_candidate;
     190                 :            :   }
     191                 :            : 
     192                 :            :   /* Get the closest candidate so far, without applying any filtering.  */
     193                 :            : 
     194                 :        149 :   candidate_t blithely_get_best_candidate () const
     195                 :            :   {
     196                 :            :     return m_best_candidate;
     197                 :            :   }
     198                 :            : 
     199                 :       7151 :   edit_distance_t get_best_distance () const { return m_best_distance; }
     200                 :          6 :   size_t get_best_candidate_length () const { return m_best_candidate_len; }
     201                 :            : 
     202                 :            :  private:
     203                 :            :   const char *m_goal;
     204                 :            :   size_t m_goal_len;
     205                 :            :   candidate_t m_best_candidate;
     206                 :            :   edit_distance_t m_best_distance;
     207                 :            :   size_t m_best_candidate_len;
     208                 :            : };
     209                 :            : 
     210                 :            : #endif  /* GCC_SPELLCHECK_H  */

Generated by: LCOV version 1.0

LCOV profile is generated on x86_64 machine using following configure options: configure --disable-bootstrap --enable-coverage=opt --enable-languages=c,c++,fortran,go,jit,lto --enable-host-shared. GCC test suite is run with the built compiler.