gcc/diagnostic-path.h

   1 /* Paths through the code associated with a diagnostic.
   2    Copyright (C) 2019-2021 Free Software Foundation, Inc.
   3    Contributed by David Malcolm <dmalcolm@redhat.com>
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along 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
  69 class 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
  88 class 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
 102 class 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
 127 class 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
 147 extern void debug (diagnostic_path *path);
 148
 149 #endif /* ! GCC_DIAGNOSTIC_PATH_H */