1/* Paths through the code associated with a diagnostic.
2   Copyright (C) 2019-2022 Free Software Foundation, Inc.
3   Contributed by David Malcolm <dmalcolm@redhat.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING3.  If not see
19<http://www.gnu.org/licenses/>.  */
20
21#ifndef GCC_DIAGNOSTIC_PATH_H
22#define GCC_DIAGNOSTIC_PATH_H
23
24#include "diagnostic.h" /* for ATTRIBUTE_GCC_DIAG.  */
25#include "diagnostic-event-id.h"
26
27/* A diagnostic_path is an optional additional piece of metadata associated
28   with a diagnostic (via its rich_location).
29
30   It describes a sequence of events predicted by the compiler that
31   lead to the problem occurring, with their locations in the user's source,
32   and text descriptions.
33
34   For example, the following error has a 3-event path:
35
36     test.c: In function 'demo':
37     test.c:29:5: error: passing NULL as argument 1 to 'PyList_Append' which
38       requires a non-NULL parameter
39        29 |     PyList_Append(list, item);
40           |     ^~~~~~~~~~~~~~~~~~~~~~~~~
41       'demo': events 1-3
42          |
43          |   25 |   list = PyList_New(0);
44          |      |          ^~~~~~~~~~~~~
45          |      |          |
46          |      |          (1) when 'PyList_New' fails, returning NULL
47          |   26 |
48          |   27 |   for (i = 0; i < count; i++) {
49          |      |   ~~~
50          |      |   |
51          |      |   (2) when 'i < count'
52          |   28 |     item = PyLong_FromLong(random());
53          |   29 |     PyList_Append(list, item);
54          |      |     ~~~~~~~~~~~~~~~~~~~~~~~~~
55          |      |     |
56          |      |     (3) when calling 'PyList_Append', passing NULL from (1) as argument 1
57          |
58
59    The diagnostic-printing code has consolidated the path into a single
60    run of events, since all the events are near each other and within the same
61    function; more complicated examples (such as interprocedural paths)
62    might be printed as multiple runs of events.  */
63
64/* Abstract base classes, describing events within a path, and the paths
65   themselves.  */
66
67/* One event within a diagnostic_path.  */
68
69class diagnostic_event
70{
71 public:
72  virtual ~diagnostic_event () {}
73
74  virtual location_t get_location () const = 0;
75
76  virtual tree get_fndecl () const = 0;
77
78  /* Stack depth, so that consumers can visualizes the interprocedural
79     calls, returns, and frame nesting.  */
80  virtual int get_stack_depth () const = 0;
81
82  /* Get a localized (and possibly colorized) description of this event.  */
83  virtual label_text get_desc (bool can_colorize) const = 0;
84};
85
86/* Abstract base class for getting at a sequence of events.  */
87
88class diagnostic_path
89{
90 public:
91  virtual ~diagnostic_path () {}
92  virtual unsigned num_events () const = 0;
93  virtual const diagnostic_event & get_event (int idx) const = 0;
94
95  bool interprocedural_p () const;
96};
97
98/* Concrete subclasses.  */
99
100/* A simple implementation of diagnostic_event.  */
101
102class simple_diagnostic_event : public diagnostic_event
103{
104 public:
105  simple_diagnostic_event (location_t loc, tree fndecl, int depth,
106			   const char *desc);
107  ~simple_diagnostic_event ();
108
109  location_t get_location () const FINAL OVERRIDE { return m_loc; }
110  tree get_fndecl () const FINAL OVERRIDE { return m_fndecl; }
111  int get_stack_depth () const FINAL OVERRIDE { return m_depth; }
112  label_text get_desc (bool) const FINAL OVERRIDE
113  {
114    return label_text::borrow (m_desc);
115  }
116
117 private:
118  location_t m_loc;
119  tree m_fndecl;
120  int m_depth;
121  char *m_desc; // has been i18n-ed and formatted
122};
123
124/* A simple implementation of diagnostic_path, as a vector of
125   simple_diagnostic_event instances.  */
126
127class simple_diagnostic_path : public diagnostic_path
128{
129 public:
130  simple_diagnostic_path (pretty_printer *event_pp)
131  : m_event_pp (event_pp) {}
132
133  unsigned num_events () const FINAL OVERRIDE;
134  const diagnostic_event & get_event (int idx) const FINAL OVERRIDE;
135
136  diagnostic_event_id_t add_event (location_t loc, tree fndecl, int depth,
137				   const char *fmt, ...)
138    ATTRIBUTE_GCC_DIAG(5,6);
139
140 private:
141  auto_delete_vec<simple_diagnostic_event> m_events;
142
143  /* (for use by add_event).  */
144  pretty_printer *m_event_pp;
145};
146
147extern void debug (diagnostic_path *path);
148
149#endif /* ! GCC_DIAGNOSTIC_PATH_H */
150