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  1. /* rddbg.c -- Read debugging information into a generic form.
  2.    Copyright 1995, 1996, 1997, 2000, 2002, 2003, 2005, 2007, 2008,
  3.    2010  Free Software Foundation, Inc.
  4.    Written by Ian Lance Taylor <ian@cygnus.com>.
  5.  
  6.    This file is part of GNU Binutils.
  7.  
  8.    This program is free software; you can redistribute it and/or modify
  9.    it under the terms of the GNU General Public License as published by
  10.    the Free Software Foundation; either version 3 of the License, or
  11.    (at your option) any later version.
  12.  
  13.    This program is distributed in the hope that it will be useful,
  14.    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16.    GNU General Public License for more details.
  17.  
  18.    You should have received a copy of the GNU General Public License
  19.    along with this program; if not, write to the Free Software
  20.    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  21.    02110-1301, USA.  */
  22.  
  23.  
  24. /* This file reads debugging information into a generic form.  This
  25.    file knows how to dig the debugging information out of an object
  26.    file.  */
  27.  
  28. #include "sysdep.h"
  29. #include "bfd.h"
  30. #include "libiberty.h"
  31. #include "bucomm.h"
  32. #include "debug.h"
  33. #include "budbg.h"
  34.  
  35. static bfd_boolean read_section_stabs_debugging_info
  36.   (bfd *, asymbol **, long, void *, bfd_boolean *);
  37. static bfd_boolean read_symbol_stabs_debugging_info
  38.   (bfd *, asymbol **, long, void *, bfd_boolean *);
  39. static bfd_boolean read_ieee_debugging_info (bfd *, void *, bfd_boolean *);
  40. static void save_stab (int, int, bfd_vma, const char *);
  41. static void stab_context (void);
  42. static void free_saved_stabs (void);
  43.  
  44. /* Read debugging information from a BFD.  Returns a generic debugging
  45.    pointer.  */
  46.  
  47. void *
  48. read_debugging_info (bfd *abfd, asymbol **syms, long symcount, bfd_boolean no_messages)
  49. {
  50.   void *dhandle;
  51.   bfd_boolean found;
  52.  
  53.   dhandle = debug_init ();
  54.   if (dhandle == NULL)
  55.     return NULL;
  56.  
  57.   if (! read_section_stabs_debugging_info (abfd, syms, symcount, dhandle,
  58.                                            &found))
  59.     return NULL;
  60.  
  61.   if (bfd_get_flavour (abfd) == bfd_target_aout_flavour)
  62.     {
  63.       if (! read_symbol_stabs_debugging_info (abfd, syms, symcount, dhandle,
  64.                                               &found))
  65.         return NULL;
  66.     }
  67.  
  68.   if (bfd_get_flavour (abfd) == bfd_target_ieee_flavour)
  69.     {
  70.       if (! read_ieee_debugging_info (abfd, dhandle, &found))
  71.         return NULL;
  72.     }
  73.  
  74.   /* Try reading the COFF symbols if we didn't find any stabs in COFF
  75.      sections.  */
  76.   if (! found
  77.       && bfd_get_flavour (abfd) == bfd_target_coff_flavour
  78.       && symcount > 0)
  79.     {
  80.       if (! parse_coff (abfd, syms, symcount, dhandle))
  81.         return NULL;
  82.       found = TRUE;
  83.     }
  84.  
  85.   if (! found)
  86.     {
  87.       if (! no_messages)
  88.         non_fatal (_("%s: no recognized debugging information"),
  89.                    bfd_get_filename (abfd));
  90.       return NULL;
  91.     }
  92.  
  93.   return dhandle;
  94. }
  95.  
  96. /* Read stabs in sections debugging information from a BFD.  */
  97.  
  98. static bfd_boolean
  99. read_section_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
  100.                                    void *dhandle, bfd_boolean *pfound)
  101. {
  102.   static struct
  103.     {
  104.       const char *secname;
  105.       const char *strsecname;
  106.     }
  107.   names[] =
  108.     {
  109.       { ".stab", ".stabstr" },
  110.       { "LC_SYMTAB.stabs", "LC_SYMTAB.stabstr" },
  111.       { "$GDB_SYMBOLS$", "$GDB_STRINGS$" }
  112.     };
  113.   unsigned int i;
  114.   void *shandle;
  115.  
  116.   *pfound = FALSE;
  117.   shandle = NULL;
  118.  
  119.   for (i = 0; i < sizeof names / sizeof names[0]; i++)
  120.     {
  121.       asection *sec, *strsec;
  122.  
  123.       sec = bfd_get_section_by_name (abfd, names[i].secname);
  124.       strsec = bfd_get_section_by_name (abfd, names[i].strsecname);
  125.       if (sec != NULL && strsec != NULL)
  126.         {
  127.           bfd_size_type stabsize, strsize;
  128.           bfd_byte *stabs, *strings;
  129.           bfd_byte *stab;
  130.           bfd_size_type stroff, next_stroff;
  131.  
  132.           stabsize = bfd_section_size (abfd, sec);
  133.           stabs = (bfd_byte *) xmalloc (stabsize);
  134.           if (! bfd_get_section_contents (abfd, sec, stabs, 0, stabsize))
  135.             {
  136.               fprintf (stderr, "%s: %s: %s\n",
  137.                        bfd_get_filename (abfd), names[i].secname,
  138.                        bfd_errmsg (bfd_get_error ()));
  139.               return FALSE;
  140.             }
  141.  
  142.           strsize = bfd_section_size (abfd, strsec);
  143.           strings = (bfd_byte *) xmalloc (strsize);
  144.           if (! bfd_get_section_contents (abfd, strsec, strings, 0, strsize))
  145.             {
  146.               fprintf (stderr, "%s: %s: %s\n",
  147.                        bfd_get_filename (abfd), names[i].strsecname,
  148.                        bfd_errmsg (bfd_get_error ()));
  149.               return FALSE;
  150.             }
  151.  
  152.           if (shandle == NULL)
  153.             {
  154.               shandle = start_stab (dhandle, abfd, TRUE, syms, symcount);
  155.               if (shandle == NULL)
  156.                 return FALSE;
  157.             }
  158.  
  159.           *pfound = TRUE;
  160.  
  161.           stroff = 0;
  162.           next_stroff = 0;
  163.           for (stab = stabs; stab < stabs + stabsize; stab += 12)
  164.             {
  165.               unsigned int strx;
  166.               int type;
  167.               int other ATTRIBUTE_UNUSED;
  168.               int desc;
  169.               bfd_vma value;
  170.  
  171.               /* This code presumes 32 bit values.  */
  172.  
  173.               strx = bfd_get_32 (abfd, stab);
  174.               type = bfd_get_8 (abfd, stab + 4);
  175.               other = bfd_get_8 (abfd, stab + 5);
  176.               desc = bfd_get_16 (abfd, stab + 6);
  177.               value = bfd_get_32 (abfd, stab + 8);
  178.  
  179.               if (type == 0)
  180.                 {
  181.                   /* Special type 0 stabs indicate the offset to the
  182.                      next string table.  */
  183.                   stroff = next_stroff;
  184.                   next_stroff += value;
  185.                 }
  186.               else
  187.                 {
  188.                   char *f, *s;
  189.  
  190.                   f = NULL;
  191.  
  192.                   if (stroff + strx > strsize)
  193.                     {
  194.                       fprintf (stderr, "%s: %s: stab entry %ld is corrupt, strx = 0x%x, type = %d\n",
  195.                                bfd_get_filename (abfd), names[i].secname,
  196.                                (long) (stab - stabs) / 12, strx, type);
  197.                       continue;
  198.                     }
  199.  
  200.                   s = (char *) strings + stroff + strx;
  201.  
  202.                   while (s[strlen (s) - 1] == '\\'
  203.                          && stab + 12 < stabs + stabsize)
  204.                     {
  205.                       char *p;
  206.  
  207.                       stab += 12;
  208.                       p = s + strlen (s) - 1;
  209.                       *p = '\0';
  210.                       s = concat (s,
  211.                                   ((char *) strings
  212.                                    + stroff
  213.                                    + bfd_get_32 (abfd, stab)),
  214.                                   (const char *) NULL);
  215.  
  216.                       /* We have to restore the backslash, because, if
  217.                          the linker is hashing stabs strings, we may
  218.                          see the same string more than once.  */
  219.                       *p = '\\';
  220.  
  221.                       if (f != NULL)
  222.                         free (f);
  223.                       f = s;
  224.                     }
  225.  
  226.                   save_stab (type, desc, value, s);
  227.  
  228.                   if (! parse_stab (dhandle, shandle, type, desc, value, s))
  229.                     {
  230.                       stab_context ();
  231.                       free_saved_stabs ();
  232.                       return FALSE;
  233.                     }
  234.  
  235.                   /* Don't free f, since I think the stabs code
  236.                      expects strings to hang around.  This should be
  237.                      straightened out.  FIXME.  */
  238.                 }
  239.             }
  240.  
  241.           free_saved_stabs ();
  242.           free (stabs);
  243.  
  244.           /* Don't free strings, since I think the stabs code expects
  245.              the strings to hang around.  This should be straightened
  246.              out.  FIXME.  */
  247.         }
  248.     }
  249.  
  250.   if (shandle != NULL)
  251.     {
  252.       if (! finish_stab (dhandle, shandle))
  253.         return FALSE;
  254.     }
  255.  
  256.   return TRUE;
  257. }
  258.  
  259. /* Read stabs in the symbol table.  */
  260.  
  261. static bfd_boolean
  262. read_symbol_stabs_debugging_info (bfd *abfd, asymbol **syms, long symcount,
  263.                                   void *dhandle, bfd_boolean *pfound)
  264. {
  265.   void *shandle;
  266.   asymbol **ps, **symend;
  267.  
  268.   shandle = NULL;
  269.   symend = syms + symcount;
  270.   for (ps = syms; ps < symend; ps++)
  271.     {
  272.       symbol_info i;
  273.  
  274.       bfd_get_symbol_info (abfd, *ps, &i);
  275.  
  276.       if (i.type == '-')
  277.         {
  278.           const char *s;
  279.           char *f;
  280.  
  281.           if (shandle == NULL)
  282.             {
  283.               shandle = start_stab (dhandle, abfd, FALSE, syms, symcount);
  284.               if (shandle == NULL)
  285.                 return FALSE;
  286.             }
  287.  
  288.           *pfound = TRUE;
  289.  
  290.           s = i.name;
  291.           f = NULL;
  292.           while (s[strlen (s) - 1] == '\\'
  293.                  && ps + 1 < symend)
  294.             {
  295.               char *sc, *n;
  296.  
  297.               ++ps;
  298.               sc = xstrdup (s);
  299.               sc[strlen (sc) - 1] = '\0';
  300.               n = concat (sc, bfd_asymbol_name (*ps), (const char *) NULL);
  301.               free (sc);
  302.               if (f != NULL)
  303.                 free (f);
  304.               f = n;
  305.               s = n;
  306.             }
  307.  
  308.           save_stab (i.stab_type, i.stab_desc, i.value, s);
  309.  
  310.           if (! parse_stab (dhandle, shandle, i.stab_type, i.stab_desc,
  311.                             i.value, s))
  312.             {
  313.               stab_context ();
  314.               free_saved_stabs ();
  315.               return FALSE;
  316.             }
  317.  
  318.           /* Don't free f, since I think the stabs code expects
  319.              strings to hang around.  This should be straightened out.
  320.              FIXME.  */
  321.         }
  322.     }
  323.  
  324.   free_saved_stabs ();
  325.  
  326.   if (shandle != NULL)
  327.     {
  328.       if (! finish_stab (dhandle, shandle))
  329.         return FALSE;
  330.     }
  331.  
  332.   return TRUE;
  333. }
  334.  
  335. /* Read IEEE debugging information.  */
  336.  
  337. static bfd_boolean
  338. read_ieee_debugging_info (bfd *abfd, void *dhandle, bfd_boolean *pfound)
  339. {
  340.   asection *dsec;
  341.   bfd_size_type size;
  342.   bfd_byte *contents;
  343.  
  344.   /* The BFD backend puts the debugging information into a section
  345.      named .debug.  */
  346.  
  347.   dsec = bfd_get_section_by_name (abfd, ".debug");
  348.   if (dsec == NULL)
  349.     return TRUE;
  350.  
  351.   size = bfd_section_size (abfd, dsec);
  352.   contents = (bfd_byte *) xmalloc (size);
  353.   if (! bfd_get_section_contents (abfd, dsec, contents, 0, size))
  354.     return FALSE;
  355.  
  356.   if (! parse_ieee (dhandle, abfd, contents, size))
  357.     return FALSE;
  358.  
  359.   free (contents);
  360.  
  361.   *pfound = TRUE;
  362.  
  363.   return TRUE;
  364. }
  366. /* Record stabs strings, so that we can give some context for errors.  */
  367.  
  368. #define SAVE_STABS_COUNT (16)
  369.  
  370. struct saved_stab
  371. {
  372.   int type;
  373.   int desc;
  374.   bfd_vma value;
  375.   char *string;
  376. };
  377.  
  378. static struct saved_stab saved_stabs[SAVE_STABS_COUNT];
  379. static int saved_stabs_index;
  380.  
  381. /* Save a stabs string.  */
  382.  
  383. static void
  384. save_stab (int type, int desc, bfd_vma value, const char *string)
  385. {
  386.   if (saved_stabs[saved_stabs_index].string != NULL)
  387.     free (saved_stabs[saved_stabs_index].string);
  388.   saved_stabs[saved_stabs_index].type = type;
  389.   saved_stabs[saved_stabs_index].desc = desc;
  390.   saved_stabs[saved_stabs_index].value = value;
  391.   saved_stabs[saved_stabs_index].string = xstrdup (string);
  392.   saved_stabs_index = (saved_stabs_index + 1) % SAVE_STABS_COUNT;
  393. }
  394.  
  395. /* Provide context for an error.  */
  396.  
  397. static void
  398. stab_context (void)
  399. {
  400.   int i;
  401.  
  402.   fprintf (stderr, _("Last stabs entries before error:\n"));
  403.   fprintf (stderr, "n_type n_desc n_value  string\n");
  404.  
  405.   i = saved_stabs_index;
  406.   do
  407.     {
  408.       struct saved_stab *stabp;
  409.  
  410.       stabp = saved_stabs + i;
  411.       if (stabp->string != NULL)
  412.         {
  413.           const char *s;
  414.  
  415.           s = bfd_get_stab_name (stabp->type);
  416.           if (s != NULL)
  417.             fprintf (stderr, "%-6s", s);
  418.           else if (stabp->type == 0)
  419.             fprintf (stderr, "HdrSym");
  420.           else
  421.             fprintf (stderr, "%-6d", stabp->type);
  422.           fprintf (stderr, " %-6d ", stabp->desc);
  423.           fprintf_vma (stderr, stabp->value);
  424.           if (stabp->type != 0)
  425.             fprintf (stderr, " %s", stabp->string);
  426.           fprintf (stderr, "\n");
  427.         }
  428.       i = (i + 1) % SAVE_STABS_COUNT;
  429.     }
  430.   while (i != saved_stabs_index);
  431. }
  432.  
  433. /* Free the saved stab strings.  */
  434.  
  435. static void
  436. free_saved_stabs (void)
  437. {
  438.   int i;
  439.  
  440.   for (i = 0; i < SAVE_STABS_COUNT; i++)
  441.     {
  442.       if (saved_stabs[i].string != NULL)
  443.         {
  444.           free (saved_stabs[i].string);
  445.           saved_stabs[i].string = NULL;
  446.         }
  447.     }
  448.  
  449.   saved_stabs_index = 0;
  450. }
  451.