1/* Source locations within string literals.
2   Copyright (C) 2016-2020 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3.  If not see
18<http://www.gnu.org/licenses/>.  */
19
20#ifndef GCC_SUBSTRING_LOCATIONS_H
21#define GCC_SUBSTRING_LOCATIONS_H
22
23/* The substring_loc class encapsulates information on the source location
24   of a range of characters within a STRING_CST.
25
26   If needed by a diagnostic, the actual location_t of the substring_loc
27   can be calculated by calling its get_location method.  This calls a
28   langhook, since this is inherently frontend-specific.  For the C family
29   of frontends, it calls back into libcpp to reparse the strings.  This
30   gets the location information "on demand", rather than storing the
31   location information in the initial lex for every string.  Thus the
32   substring_loc can also be thought of as a deferred call into libcpp,
33   to allow the non-trivial work of reparsing the string to be delayed
34   until we actually need it (to emit a diagnostic for a particular range
35   of characters).
36
37   substring_loc::get_location returns NULL if it succeeds, or an
38   error message if it fails.  Error messages are intended for GCC
39   developers (to help debugging) rather than for end-users.
40
41   The easiest way to use a substring_loc is via the format_warning_* APIs,
42   which gracefully handle failure of substring_loc::get_location by using
43   the location of the string as a whole if substring-information is
44   unavailable.  */
45
46class substring_loc
47{
48 public:
49  /* Constructor.  FMT_STRING_LOC is the location of the string as
50     a whole.  STRING_TYPE is the type of the string.  It should be an
51     ARRAY_TYPE of INTEGER_TYPE, or a POINTER_TYPE to such an ARRAY_TYPE.
52     CARET_IDX, START_IDX, and END_IDX are offsets from the start
53     of the string data.  */
54  substring_loc (location_t fmt_string_loc, tree string_type,
55		 int caret_idx, int start_idx, int end_idx)
56  : m_fmt_string_loc (fmt_string_loc), m_string_type (string_type),
57    m_caret_idx (caret_idx), m_start_idx (start_idx), m_end_idx (end_idx) {}
58
59  void set_caret_index (int caret_idx) { m_caret_idx = caret_idx; }
60
61  const char *get_location (location_t *out_loc) const;
62
63  location_t get_fmt_string_loc () const { return m_fmt_string_loc; }
64  tree get_string_type () const { return m_string_type; }
65  int get_caret_idx () const { return m_caret_idx; }
66  int get_start_idx () const { return m_start_idx; }
67  int get_end_idx () const { return m_end_idx; }
68
69 private:
70  location_t m_fmt_string_loc;
71  tree m_string_type;
72  int m_caret_idx;
73  int m_start_idx;
74  int m_end_idx;
75};
76
77/* A bundle of state for emitting a diagnostic relating to a format string.  */
78
79class format_string_diagnostic_t
80{
81 public:
82  format_string_diagnostic_t (const substring_loc &fmt_loc,
83			      const range_label *fmt_label,
84			      location_t param_loc,
85			      const range_label *param_label,
86			      const char *corrected_substring);
87
88  /* Functions for emitting a warning about a format string.  */
89
90  bool emit_warning_va (int opt, const char *gmsgid, va_list *ap) const
91    ATTRIBUTE_GCC_DIAG (3, 0);
92
93  bool emit_warning_n_va (int opt, unsigned HOST_WIDE_INT n,
94			  const char *singular_gmsgid,
95			  const char *plural_gmsgid, va_list *ap) const
96  ATTRIBUTE_GCC_DIAG (4, 0) ATTRIBUTE_GCC_DIAG (5, 0);
97
98  bool emit_warning (int opt, const char *gmsgid, ...) const
99    ATTRIBUTE_GCC_DIAG (3, 4);
100
101  bool emit_warning_n (int opt, unsigned HOST_WIDE_INT n,
102		       const char *singular_gmsgid,
103		       const char *plural_gmsgid, ...) const
104  ATTRIBUTE_GCC_DIAG (4, 6) ATTRIBUTE_GCC_DIAG (5, 6);
105
106 private:
107  const substring_loc &m_fmt_loc;
108  const range_label *m_fmt_label;
109  location_t m_param_loc;
110  const range_label *m_param_label;
111  const char *m_corrected_substring;
112};
113
114
115/* Implementation detail, for use when implementing
116   LANG_HOOKS_GET_SUBSTRING_LOCATION.  */
117
118extern const char *get_location_within_string (cpp_reader *pfile,
119					       string_concat_db *concats,
120					       location_t strloc,
121					       enum cpp_ttype type,
122					       int caret_idx,
123					       int start_idx, int end_idx,
124					       location_t *out_loc);
125
126#endif /* ! GCC_SUBSTRING_LOCATIONS_H */
127