1 /* Support for offering suggestions for handling unrecognized names.
2    Copyright (C) 2016-2018 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_NAME_HINT_H
21 #define GCC_NAME_HINT_H
22 
23 /* This header uses gnu::unique_ptr, but unique-ptr.h can't be directly
24    included due to issues with macros.  Hence it must be included from
25    system.h by defining INCLUDE_UNIQUE_PTR in any source file using it.  */
26 
27 #ifndef GNU_UNIQUE_PTR_H
28 # error "You must define INCLUDE_UNIQUE_PTR before including system.h to use name-hint.h"
29 #endif
30 
31 enum lookup_name_fuzzy_kind {
32   /* Names of types.  */
33   FUZZY_LOOKUP_TYPENAME,
34 
35   /* Names of function decls.  */
36   FUZZY_LOOKUP_FUNCTION_NAME,
37 
38   /* Any name.  */
39   FUZZY_LOOKUP_NAME
40 };
41 
42 /* A deferred_diagnostic is a wrapper around optional extra diagnostics
43    that we may want to bundle into a name_hint.
44 
45    The diagnostic is emitted by the subclass destructor, which should
46    check that is_suppressed_p () is not true.  */
47 
48 class deferred_diagnostic
49 {
50  public:
51   virtual ~deferred_diagnostic () {}
52 
53   location_t get_location () const { return m_loc; }
54 
55   /* Call this if the corresponding warning was not emitted,
56      in which case we should also not emit the deferred_diagnostic.  */
57   void suppress ()
58   {
59     m_suppress = true;
60   }
61 
62   bool is_suppressed_p () const { return m_suppress; }
63 
64  protected:
65   deferred_diagnostic (location_t loc)
66   : m_loc (loc), m_suppress (false) {}
67 
68  private:
69   location_t m_loc;
70   bool m_suppress;
71 };
72 
73 /* A name_hint is an optional string suggestion, along with an
74    optional deferred_diagnostic.
75    For example:
76 
77        error: unknown foo named 'bar'
78 
79    if the SUGGESTION is "baz", then one might print:
80 
81        error: unknown foo named 'bar'; did you mean 'baz'?
82 
83    and the deferred_diagnostic allows for additional (optional)
84    diagnostics e.g.:
85 
86        note: did you check behind the couch?
87 
88    The deferred_diagnostic is emitted by its destructor, when the
89    name_hint goes out of scope.  */
90 
91 class name_hint
92 {
93 public:
94   name_hint () : m_suggestion (NULL), m_deferred () {}
95 
96   name_hint (const char *suggestion, deferred_diagnostic *deferred)
97   : m_suggestion (suggestion), m_deferred (deferred)
98   {
99   }
100 
101   const char *suggestion () const { return m_suggestion; }
102   operator bool () const { return m_suggestion != NULL; }
103 
104   /* Call this on a name_hint if the corresponding warning was not emitted,
105      in which case we should also not emit the deferred_diagnostic.  */
106 
107   void suppress ()
108   {
109     if (m_deferred)
110       m_deferred->suppress ();
111   }
112 
113 private:
114   const char *m_suggestion;
115   gnu::unique_ptr<deferred_diagnostic> m_deferred;
116 };
117 
118 extern name_hint lookup_name_fuzzy (tree, enum lookup_name_fuzzy_kind,
119 				    location_t);
120 
121 #endif /* ! GCC_NAME_HINT_H */
122