gdb/dwarf2/section.c

   1 /* DWARF 2 low-level section code
   2
   3    Copyright (C) 1994-2020 Free Software Foundation, Inc.
   4
   5    Adapted by Gary Funck (gary@intrepid.com), Intrepid Technology,
   6    Inc.  with support from Florida State University (under contract
   7    with the Ada Joint Program Office), and Silicon Graphics, Inc.
   8    Initial contribution by Brent Benson, Harris Computer Systems, Inc.,
   9    based on Fred Fish's (Cygnus Support) implementation of DWARF 1
  10    support.
  11
  12    This file is part of GDB.
  13
  14    This program is free software; you can redistribute it and/or modify
  15    it under the terms of the GNU General Public License as published by
  16    the Free Software Foundation; either version 3 of the License, or
  17    (at your option) any later version.
  18
  19    This program is distributed in the hope that it will be useful,
  20    but WITHOUT ANY WARRANTY; without even the implied warranty of
  21    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22    GNU General Public License for more details.
  23
  24    You should have received a copy of the GNU General Public License
  25    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  26
  27 #include "defs.h"
  28 #include "dwarf2/section.h"
  29 #include "gdb_bfd.h"
  30 #include "objfiles.h"
  31 #include "complaints.h"
  32
  33 void
  34 dwarf2_section_buffer_overflow_complaint (struct dwarf2_section_info *section)
  35 {
  36   complaint (_("debug info runs off end of %s section"
  37                " [in module %s]"),
  38              section->get_name (),
  39              section->get_file_name ());
  40 }
  41
  42 struct dwarf2_section_info *
  43 dwarf2_section_info::get_containing_section () const
  44 {
  45   gdb_assert (is_virtual);
  46   return s.containing_section;
  47 }
  48
  49 struct bfd *
  50 dwarf2_section_info::get_bfd_owner () const
  51 {
  52   const dwarf2_section_info *section = this;
  53   if (is_virtual)
  54     {
  55       section = get_containing_section ();
  56       gdb_assert (!section->is_virtual);
  57     }
  58   return section->s.section->owner;
  59 }
  60
  61 asection *
  62 dwarf2_section_info::get_bfd_section () const
  63 {
  64   const dwarf2_section_info *section = this;
  65   if (section->is_virtual)
  66     {
  67       section = get_containing_section ();
  68       gdb_assert (!section->is_virtual);
  69     }
  70   return section->s.section;
  71 }
  72
  73 const char *
  74 dwarf2_section_info::get_name () const
  75 {
  76   asection *sectp = get_bfd_section ();
  77
  78   gdb_assert (sectp != NULL);
  79   return bfd_section_name (sectp);
  80 }
  81
  82 const char *
  83 dwarf2_section_info::get_file_name () const
  84 {
  85   bfd *abfd = get_bfd_owner ();
  86
  87   return bfd_get_filename (abfd);
  88 }
  89
  90 int
  91 dwarf2_section_info::get_id () const
  92 {
  93   asection *sectp = get_bfd_section ();
  94
  95   if (sectp == NULL)
  96     return 0;
  97   return sectp->id;
  98 }
  99
 100 int
 101 dwarf2_section_info::get_flags () const
 102 {
 103   asection *sectp = get_bfd_section ();
 104
 105   gdb_assert (sectp != NULL);
 106   return bfd_section_flags (sectp);
 107 }
 108
 109 bool
 110 dwarf2_section_info::empty () const
 111 {
 112   if (is_virtual)
 113     return size == 0;
 114   return s.section == NULL || size == 0;
 115 }
 116
 117 void
 118 dwarf2_section_info::read (struct objfile *objfile)
 119 {
 120   asection *sectp;
 121   bfd *abfd;
 122   gdb_byte *buf, *retbuf;
 123
 124   if (readin)
 125     return;
 126   buffer = NULL;
 127   readin = true;
 128
 129   if (empty ())
 130     return;
 131
 132   sectp = get_bfd_section ();
 133
 134   /* If this is a virtual section we need to read in the real one first.  */
 135   if (is_virtual)
 136     {
 137       struct dwarf2_section_info *containing_section =
 138         get_containing_section ();
 139
 140       gdb_assert (sectp != NULL);
 141       if ((sectp->flags & SEC_RELOC) != 0)
 142         {
 143           error (_("Dwarf Error: DWP format V2 with relocations is not"
 144                    " supported in section %s [in module %s]"),
 145                  get_name (), get_file_name ());
 146         }
 147       containing_section->read (objfile);
 148       /* Other code should have already caught virtual sections that don't
 149          fit.  */
 150       gdb_assert (virtual_offset + size <= containing_section->size);
 151       /* If the real section is empty or there was a problem reading the
 152          section we shouldn't get here.  */
 153       gdb_assert (containing_section->buffer != NULL);
 154       buffer = containing_section->buffer + virtual_offset;
 155       return;
 156     }
 157
 158   /* If the section has relocations, we must read it ourselves.
 159      Otherwise we attach it to the BFD.  */
 160   if ((sectp->flags & SEC_RELOC) == 0)
 161     {
 162       buffer = gdb_bfd_map_section (sectp, &size);
 163       return;
 164     }
 165
 166   buf = (gdb_byte *) obstack_alloc (&objfile->objfile_obstack, size);
 167   buffer = buf;
 168
 169   /* When debugging .o files, we may need to apply relocations; see
 170      http://sourceware.org/ml/gdb-patches/2002-04/msg00136.html .
 171      We never compress sections in .o files, so we only need to
 172      try this when the section is not compressed.  */
 173   retbuf = symfile_relocate_debug_section (objfile, sectp, buf);
 174   if (retbuf != NULL)
 175     {
 176       buffer = retbuf;
 177       return;
 178     }
 179
 180   abfd = get_bfd_owner ();
 181   gdb_assert (abfd != NULL);
 182
 183   if (bfd_seek (abfd, sectp->filepos, SEEK_SET) != 0
 184       || bfd_bread (buf, size, abfd) != size)
 185     {
 186       error (_("Dwarf Error: Can't read DWARF data"
 187                " in section %s [in module %s]"),
 188              bfd_section_name (sectp), bfd_get_filename (abfd));
 189     }
 190 }