gdb/dwarf2/die.h

   1 /* DWARF DIEs
   2
   3    Copyright (C) 2003-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef GDB_DWARF2_DIE_H
  21 #define GDB_DWARF2_DIE_H
  22
  23 #include "complaints.h"
  24 #include "dwarf2/attribute.h"
  25
  26 /* This data structure holds a complete die structure.  */
  27 struct die_info
  28 {
  29   /* Allocate a new die_info on OBSTACK.  NUM_ATTRS is the number of
  30      attributes that are needed.  */
  31   static die_info *allocate (struct obstack *obstack, int num_attrs);
  32
  33   /* Dump this DIE and any children to MAX_LEVEL.  They are written to
  34      gdb_stdlog.  Note this is called from the pdie user command in
  35      gdb-gdb.gdb.  */
  36   void dump (int max_level);
  37
  38   /* Shallowly dump this DIE to gdb_stderr.  */
  39   void error_dump ();
  40
  41   /* Return the named attribute or NULL if not there, but do not
  42      follow DW_AT_specification, etc.  */
  43   struct attribute *attr (dwarf_attribute name)
  44   {
  45     for (unsigned i = 0; i < num_attrs; ++i)
  46       if (attrs[i].name == name)
  47         return &attrs[i];
  48     return NULL;
  49   }
  50
  51   /* Return the address base of the compile unit, which, if exists, is
  52      stored either at the attribute DW_AT_GNU_addr_base, or
  53      DW_AT_addr_base.  */
  54   std::optional<ULONGEST> addr_base ()
  55   {
  56     for (unsigned i = 0; i < num_attrs; ++i)
  57       if (attrs[i].name == DW_AT_addr_base
  58            || attrs[i].name == DW_AT_GNU_addr_base)
  59         {
  60           if (attrs[i].form_is_unsigned ())
  61             {
  62               /* If both exist, just use the first one.  */
  63               return attrs[i].as_unsigned ();
  64             }
  65           complaint (_("address base attribute (offset %s) as wrong form"),
  66                      sect_offset_str (sect_off));
  67         }
  68     return std::optional<ULONGEST> ();
  69   }
  70
  71   /* Return the base address of the compile unit into the .debug_ranges section,
  72      which, if exists, is stored in the DW_AT_GNU_ranges_base attribute.  This
  73      value is only relevant in pre-DWARF 5 split-unit scenarios.  */
  74   ULONGEST gnu_ranges_base ()
  75   {
  76     for (unsigned i = 0; i < num_attrs; ++i)
  77       if (attrs[i].name == DW_AT_GNU_ranges_base)
  78         {
  79           if (attrs[i].form_is_unsigned ())
  80             return attrs[i].as_unsigned ();
  81
  82           complaint (_("ranges base attribute (offset %s) has wrong form"),
  83                      sect_offset_str (sect_off));
  84         }
  85
  86     return 0;
  87   }
  88
  89   /* Return the rnglists base of the compile unit, which, if exists, is stored
  90      in the DW_AT_rnglists_base attribute.  */
  91   ULONGEST rnglists_base ()
  92   {
  93     for (unsigned i = 0; i < num_attrs; ++i)
  94       if (attrs[i].name == DW_AT_rnglists_base)
  95         {
  96           if (attrs[i].form_is_unsigned ())
  97             return attrs[i].as_unsigned ();
  98
  99           complaint (_("rnglists base attribute (offset %s) has wrong form"),
 100                      sect_offset_str (sect_off));
 101         }
 102
 103     return 0;
 104   }
 105
 106   /* DWARF-2 tag for this DIE.  */
 107   ENUM_BITFIELD(dwarf_tag) tag : 16;
 108
 109   /* Number of attributes */
 110   unsigned char num_attrs;
 111
 112   /* True if we're presently building the full type name for the
 113      type derived from this DIE.  */
 114   unsigned char building_fullname : 1;
 115
 116   /* True if this die is in process.  PR 16581.  */
 117   unsigned char in_process : 1;
 118
 119   /* True if this DIE has children.  */
 120   unsigned char has_children : 1;
 121
 122   /* Abbrev number */
 123   unsigned int abbrev;
 124
 125   /* Offset in .debug_info or .debug_types section.  */
 126   sect_offset sect_off;
 127
 128   /* The dies in a compilation unit form an n-ary tree.  PARENT
 129      points to this die's parent; CHILD points to the first child of
 130      this node; and all the children of a given node are chained
 131      together via their SIBLING fields.  */
 132   struct die_info *child;       /* Its first child, if any.  */
 133   struct die_info *sibling;     /* Its next sibling, if any.  */
 134   struct die_info *parent;      /* Its parent, if any.  */
 135
 136   /* An array of attributes, with NUM_ATTRS elements.  There may be
 137      zero, but it's not common and zero-sized arrays are not
 138      sufficiently portable C.  */
 139   struct attribute attrs[1];
 140 };
 141
 142 /* Key hash type to store die_info objects in gdb::unordered_set, identified by
 143    their section offsets.  */
 144
 145 struct die_info_hash_sect_off final
 146 {
 147   using is_transparent = void;
 148
 149   std::size_t operator() (const die_info *die) const noexcept
 150   { return (*this) (die->sect_off); }
 151
 152   std::size_t operator() (sect_offset offset) const noexcept
 153   { return std::hash<sect_offset> () (offset); }
 154 };
 155
 156 /* Key equal type to store die_info objects in gdb::unordered_set, identified by
 157    their section offsets.  */
 158
 159 struct die_info_eq_sect_off final
 160 {
 161   using is_transparent = void;
 162
 163   bool operator() (const die_info *a, const die_info *b) const noexcept
 164   { return (*this) (a->sect_off, b); }
 165
 166   bool operator() (sect_offset offset, const die_info *die) const noexcept
 167   { return offset == die->sect_off; }
 168 };
 169
 170 #endif /* GDB_DWARF2_DIE_H */