gdb/paread.c

   1 /* Read HP PA/Risc object files for GDB.
   2    Copyright 1991, 1992 Free Software Foundation, Inc.
   3    Written by Fred Fish at Cygnus Support.
   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 2 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, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #include "defs.h"
  22 #include "bfd.h"
  23 #include <time.h> /* For time_t in libbfd.h.  */
  24 #include <sys/types.h> /* For time_t, if not in time.h.  */
  25 #include "libbfd.h"
  26 #include "som.h"
  27 #include <syms.h>
  28 #include "symtab.h"
  29 #include "symfile.h"
  30 #include "objfiles.h"
  31 #include "buildsym.h"
  32 #include "stabsread.h"
  33 #include "gdb-stabs.h"
  34 #include "complaints.h"
  35 #include <string.h>
  36 #include "demangle.h"
  37 #include <sys/file.h>
  38
  39 /* Size of n_value and n_strx fields in a stab symbol.  */
  40 #define BYTES_IN_WORD 4
  41
  42 #include "aout/aout64.h"
  43
  44 /* Various things we might complain about... */
  45
  46 static void
  47 pa_symfile_init PARAMS ((struct objfile *));
  48
  49 static void
  50 pa_new_init PARAMS ((struct objfile *));
  51
  52 static void
  53 read_unwind_info PARAMS ((struct objfile *));
  54
  55 static void
  56 pa_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  57
  58 static void
  59 pa_symfile_finish PARAMS ((struct objfile *));
  60
  61 static void
  62 pa_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *));
  63
  64 static void
  65 free_painfo PARAMS ((PTR));
  66
  67 static struct section_offsets *
  68 pa_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
  69
  70 static void
  71 record_minimal_symbol PARAMS ((char *, CORE_ADDR,
  72                                enum minimal_symbol_type,
  73                                struct objfile *));
  74
  75 static void
  76 record_minimal_symbol (name, address, ms_type, objfile)
  77      char *name;
  78      CORE_ADDR address;
  79      enum minimal_symbol_type ms_type;
  80      struct objfile *objfile;
  81 {
  82   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  83   prim_record_minimal_symbol (name, address, ms_type);
  84 }
  85
  86 /*
  87
  88 LOCAL FUNCTION
  89
  90         pa_symtab_read -- read the symbol table of a PA file
  91
  92 SYNOPSIS
  93
  94         void pa_symtab_read (bfd *abfd, CORE_ADDR addr,
  95                               struct objfile *objfile)
  96
  97 DESCRIPTION
  98
  99         Given an open bfd, a base address to relocate symbols to, and a
 100         flag that specifies whether or not this bfd is for an executable
 101         or not (may be shared library for example), add all the global
 102         function and data symbols to the minimal symbol table.
 103 */
 104
 105 static void
 106 pa_symtab_read (abfd, addr, objfile)
 107      bfd *abfd;
 108      CORE_ADDR addr;
 109      struct objfile *objfile;
 110 {
 111   unsigned int number_of_symbols;
 112   unsigned int i;
 113   int val;
 114   char *stringtab;
 115   struct symbol_dictionary_record *buf, *bufp, *endbufp;
 116   char *symname;
 117   CONST int symsize = sizeof (struct symbol_dictionary_record);
 118
 119   number_of_symbols = bfd_get_symcount (abfd);
 120
 121   buf = alloca (symsize * number_of_symbols);
 122   bfd_seek (abfd, obj_sym_filepos (abfd), L_SET);
 123   val = bfd_read (buf, symsize * number_of_symbols, 1, abfd);
 124   if (val != symsize * number_of_symbols)
 125     error ("Couldn't read symbol dictionary!");
 126
 127   stringtab = alloca (obj_stringtab_size (abfd));
 128   bfd_seek (abfd, obj_str_filepos (abfd), L_SET);
 129   val = bfd_read (stringtab, obj_stringtab_size (abfd), 1, abfd);
 130   if (val != obj_stringtab_size (abfd))
 131     error ("Can't read in HP string table.");
 132
 133   endbufp = buf + number_of_symbols;
 134   for (bufp = buf; bufp < endbufp; ++bufp)
 135     {
 136       enum minimal_symbol_type ms_type;
 137
 138       QUIT;
 139
 140       switch (bufp->symbol_scope)
 141         {
 142         case SS_UNIVERSAL:
 143           switch (bufp->symbol_type)
 144             {
 145             case ST_SYM_EXT:
 146             case ST_ARG_EXT:
 147               continue;
 148
 149             case ST_CODE:
 150             case ST_PRI_PROG:
 151             case ST_SEC_PROG:
 152             case ST_ENTRY:
 153             case ST_MILLICODE:
 154               symname = bufp->name.n_strx + stringtab;
 155               ms_type = mst_text;
 156               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 157               break;
 158             case ST_DATA:
 159               symname = bufp->name.n_strx + stringtab;
 160               ms_type = mst_data;
 161               break;
 162             default:
 163               continue;
 164             }
 165           break;
 166
 167 #if 0
 168           /* SS_GLOBAL and SS_LOCAL are two names for the same thing (!).  */
 169         case SS_GLOBAL:
 170 #endif
 171         case SS_LOCAL:
 172           switch (bufp->symbol_type)
 173             {
 174             case ST_SYM_EXT:
 175             case ST_ARG_EXT:
 176               continue;
 177
 178             case ST_CODE:
 179               symname = bufp->name.n_strx + stringtab;
 180               ms_type = mst_file_text;
 181               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 182
 183             check_strange_names:
 184               /* GAS leaves symbols with the prefixes "LS$", "LBB$",
 185                  and "LBE$" in .o files after assembling.  And thus
 186                  they appear in the final executable.  This can
 187                  cause problems if these special symbols have the
 188                  same value as real symbols.  So ignore them.  Also "LC$".  */
 189               if (*symname == 'L'
 190                   && (symname[2] == '$' || symname[3] == '$'))
 191                 continue;
 192               break;
 193
 194             case ST_PRI_PROG:
 195             case ST_SEC_PROG:
 196             case ST_ENTRY:
 197             case ST_MILLICODE:
 198               symname = bufp->name.n_strx + stringtab;
 199               ms_type = mst_file_text;
 200               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 201               break;
 202
 203             case ST_DATA:
 204               symname = bufp->name.n_strx + stringtab;
 205               ms_type = mst_file_data;
 206               goto check_strange_names;
 207
 208             default:
 209               continue;
 210             }
 211           break;
 212
 213         default:
 214           continue;
 215         }
 216
 217       if (bufp->name.n_strx > obj_stringtab_size (abfd))
 218         error ("Invalid symbol data; bad HP string table offset: %d",
 219                bufp->name.n_strx);
 220
 221       record_minimal_symbol (symname,
 222                              bufp->symbol_value, ms_type,
 223                              objfile);
 224     }
 225
 226   install_minimal_symbols (objfile);
 227 }
 228
 229 /* Read in the backtrace information stored in the `$UNWIND_START$' section of
 230    the object file.  This info is used mainly by find_unwind_entry() to find
 231    out the stack frame size and frame pointer used by procedures.  We put
 232    everything on the psymbol obstack in the objfile so that it automatically
 233    gets freed when the objfile is destroyed.  */
 234
 235 static void
 236 read_unwind_info (objfile)
 237      struct objfile *objfile;
 238 {
 239   asection *unwind_sec;
 240   struct obj_unwind_info *ui;
 241
 242   ui = obstack_alloc (&objfile->psymbol_obstack,
 243                       sizeof (struct obj_unwind_info));
 244
 245   ui->table = NULL;
 246   ui->cache = NULL;
 247   ui->last = -1;
 248
 249   unwind_sec = bfd_get_section_by_name (objfile->obfd,
 250                                         "$UNWIND_START$");
 251   if (unwind_sec)
 252     {
 253       int size;
 254       int i, *ip;
 255
 256       size = bfd_section_size (objfile->obfd, unwind_sec);
 257       ui->table = obstack_alloc (&objfile->psymbol_obstack, size);
 258       ui->last = size / sizeof (struct unwind_table_entry) - 1;
 259
 260       bfd_get_section_contents (objfile->obfd, unwind_sec, ui->table,
 261                                 0, size);
 262
 263       OBJ_UNWIND_INFO (objfile) = ui;
 264     }
 265 }
 266
 267 /* Scan and build partial symbols for a symbol file.
 268    We have been initialized by a call to pa_symfile_init, which
 269    currently does nothing.
 270
 271    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 272    in each section.  This is ignored, as it isn't needed for the PA.
 273
 274    MAINLINE is true if we are reading the main symbol
 275    table (as opposed to a shared lib or dynamically loaded file).
 276
 277    This function only does the minimum work necessary for letting the
 278    user "name" things symbolically; it does not read the entire symtab.
 279    Instead, it reads the external and static symbols and puts them in partial
 280    symbol tables.  When more extensive information is requested of a
 281    file, the corresponding partial symbol table is mutated into a full
 282    fledged symbol table by going back and reading the symbols
 283    for real.
 284
 285    We look for sections with specific names, to tell us what debug
 286    format to look for:  FIXME!!!
 287
 288    pastab_build_psymtabs() handles STABS symbols.
 289
 290    Note that PA files have a "minimal" symbol table, which is vaguely
 291    reminiscent of a COFF symbol table, but has only the minimal information
 292    necessary for linking.  We process this also, and use the information to
 293    build gdb's minimal symbol table.  This gives us some minimal debugging
 294    capability even for files compiled without -g.  */
 295
 296 static void
 297 pa_symfile_read (objfile, section_offsets, mainline)
 298      struct objfile *objfile;
 299      struct section_offsets *section_offsets;
 300      int mainline;
 301 {
 302   bfd *abfd = objfile->obfd;
 303   struct cleanup *back_to;
 304   CORE_ADDR offset;
 305
 306   init_minimal_symbol_collection ();
 307   back_to = make_cleanup (discard_minimal_symbols, 0);
 308
 309   make_cleanup (free_painfo, (PTR) objfile);
 310
 311   /* Process the normal PA symbol table first. */
 312
 313   /* FIXME, should take a section_offsets param, not just an offset.  */
 314
 315   offset = ANOFFSET (section_offsets, 0);
 316   pa_symtab_read (abfd, offset, objfile);
 317
 318   /* Now process debugging information, which is contained in
 319      special PA sections.  */
 320
 321   pastab_build_psymtabs (objfile, section_offsets, mainline);
 322
 323   read_unwind_info(objfile);
 324
 325   do_cleanups (back_to);
 326 }
 327
 328 /* This cleans up the objfile's sym_stab_info pointer, and the chain of
 329    stab_section_info's, that might be dangling from it.  */
 330
 331 static void
 332 free_painfo (objp)
 333      PTR objp;
 334 {
 335   struct objfile *objfile = (struct objfile *)objp;
 336   struct dbx_symfile_info *dbxinfo = (struct dbx_symfile_info *)
 337                                      objfile->sym_stab_info;
 338   struct stab_section_info *ssi, *nssi;
 339
 340   ssi = dbxinfo->stab_section_info;
 341   while (ssi)
 342     {
 343       nssi = ssi->next;
 344       mfree (objfile->md, ssi);
 345       ssi = nssi;
 346     }
 347
 348   dbxinfo->stab_section_info = 0;       /* Just say No mo info about this.  */
 349 }
 350
 351 /* Initialize anything that needs initializing when a completely new symbol
 352    file is specified (not just adding some symbols from another file, e.g. a
 353    shared library).
 354
 355    We reinitialize buildsym, since we may be reading stabs from a PA file.  */
 356
 357 static void
 358 pa_new_init (ignore)
 359      struct objfile *ignore;
 360 {
 361   stabsread_new_init ();
 362   buildsym_new_init ();
 363 }
 364
 365 /* Perform any local cleanups required when we are done with a particular
 366    objfile.  I.E, we are in the process of discarding all symbol information
 367    for an objfile, freeing up all memory held for it, and unlinking the
 368    objfile struct from the global list of known objfiles. */
 369
 370 static void
 371 pa_symfile_finish (objfile)
 372      struct objfile *objfile;
 373 {
 374   if (objfile -> sym_stab_info != NULL)
 375     {
 376       mfree (objfile -> md, objfile -> sym_stab_info);
 377     }
 378 }
 379
 380 /* PA specific initialization routine for reading symbols.
 381
 382    It is passed a pointer to a struct sym_fns which contains, among other
 383    things, the BFD for the file whose symbols are being read, and a slot for
 384    a pointer to "private data" which we can fill with goodies.
 385
 386    This routine is almost a complete ripoff of dbx_symfile_init.  The
 387    common parts of these routines should be extracted and used instead of
 388    duplicating this code.  FIXME. */
 389
 390 static void
 391 pa_symfile_init (objfile)
 392      struct objfile *objfile;
 393 {
 394   int val;
 395   bfd *sym_bfd = objfile->obfd;
 396   char *name = bfd_get_filename (sym_bfd);
 397   asection *stabsect;           /* Section containing symbol table entries */
 398   asection *stringsect;         /* Section containing symbol name strings */
 399
 400   stabsect = bfd_get_section_by_name (sym_bfd, "$GDB_SYMBOLS$");
 401   stringsect = bfd_get_section_by_name (sym_bfd, "$GDB_STRINGS$");
 402
 403   /* Allocate struct to keep track of the symfile */
 404   objfile->sym_stab_info = (PTR)
 405     xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
 406
 407   memset ((PTR) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info));
 408
 409   if (!stabsect)
 410     return;
 411
 412   if (!stringsect)
 413     error ("Found stabs, but not string section");
 414
 415   /* FIXME POKING INSIDE BFD DATA STRUCTURES */
 416 #define STRING_TABLE_OFFSET     (stringsect->filepos)
 417 #define SYMBOL_TABLE_OFFSET     (stabsect->filepos)
 418
 419   /* FIXME POKING INSIDE BFD DATA STRUCTURES */
 420
 421   DBX_SYMFILE_INFO (objfile)->stab_section_info = NULL;
 422   DBX_TEXT_SECT (objfile) = bfd_get_section_by_name (sym_bfd, ".text");
 423   if (!DBX_TEXT_SECT (objfile))
 424     error ("Can't find .text section in symbol file");
 425
 426   /* FIXME: I suspect this should be external_nlist.  The size of host
 427      types like long and bfd_vma should not affect how we read the
 428      file.  */
 429   DBX_SYMBOL_SIZE (objfile) = sizeof (struct internal_nlist);
 430   DBX_SYMCOUNT (objfile) = bfd_section_size (sym_bfd, stabsect)
 431     / DBX_SYMBOL_SIZE (objfile);
 432   DBX_SYMTAB_OFFSET (objfile) = SYMBOL_TABLE_OFFSET;
 433
 434   /* Read the string table and stash it away in the psymbol_obstack.  It is
 435      only needed as long as we need to expand psymbols into full symbols,
 436      so when we blow away the psymbol the string table goes away as well.
 437      Note that gdb used to use the results of attempting to malloc the
 438      string table, based on the size it read, as a form of sanity check
 439      for botched byte swapping, on the theory that a byte swapped string
 440      table size would be so totally bogus that the malloc would fail.  Now
 441      that we put in on the psymbol_obstack, we can't do this since gdb gets
 442      a fatal error (out of virtual memory) if the size is bogus.  We can
 443      however at least check to see if the size is zero or some negative
 444      value. */
 445
 446   DBX_STRINGTAB_SIZE (objfile) = bfd_section_size (sym_bfd, stringsect);
 447
 448   if (DBX_SYMCOUNT (objfile) == 0
 449       || DBX_STRINGTAB_SIZE (objfile) == 0)
 450     return;
 451
 452   if (DBX_STRINGTAB_SIZE (objfile) <= 0
 453       || DBX_STRINGTAB_SIZE (objfile) > bfd_get_size (sym_bfd))
 454     error ("ridiculous string table size (%d bytes).",
 455            DBX_STRINGTAB_SIZE (objfile));
 456
 457   DBX_STRINGTAB (objfile) =
 458     (char *) obstack_alloc (&objfile -> psymbol_obstack,
 459                             DBX_STRINGTAB_SIZE (objfile));
 460
 461   /* Now read in the string table in one big gulp.  */
 462
 463   val = bfd_seek (sym_bfd, STRING_TABLE_OFFSET, L_SET);
 464   if (val < 0)
 465     perror_with_name (name);
 466   val = bfd_read (DBX_STRINGTAB (objfile), DBX_STRINGTAB_SIZE (objfile), 1,
 467                   sym_bfd);
 468   if (val == 0)
 469     error ("End of file reading string table");
 470   else if (val < 0)
 471     /* It's possible bfd_read should be setting bfd_error, and we should be
 472        checking that.  But currently it doesn't set bfd_error.  */
 473     perror_with_name (name);
 474   else if (val != DBX_STRINGTAB_SIZE (objfile))
 475     error ("Short read reading string table");
 476 }
 477
 478 /* PA specific parsing routine for section offsets.
 479
 480    Plain and simple for now.  */
 481
 482 static struct section_offsets *
 483 pa_symfile_offsets (objfile, addr)
 484      struct objfile *objfile;
 485      CORE_ADDR addr;
 486 {
 487   struct section_offsets *section_offsets;
 488   int i;
 489
 490   section_offsets = (struct section_offsets *)
 491     obstack_alloc (&objfile -> psymbol_obstack,
 492                    sizeof (struct section_offsets) +
 493                           sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 494
 495   for (i = 0; i < SECT_OFF_MAX; i++)
 496     ANOFFSET (section_offsets, i) = addr;
 497
 498   return section_offsets;
 499 }
 500 \f
 501 /*  Register that we are able to handle PA object file formats. */
 502
 503 /* This is probably a mistake.  FIXME.  Why can't the HP's use an ordinary
 504    file format name with an -hppa suffix?  */
 505 static struct sym_fns pa_sym_fns =
 506 {
 507   "hppa",               /* sym_name: name or name prefix of BFD target type */
 508   4,                    /* sym_namelen: number of significant sym_name chars */
 509   pa_new_init,          /* sym_new_init: init anything gbl to entire symtab */
 510   pa_symfile_init,      /* sym_init: read initial info, setup for sym_read() */
 511   pa_symfile_read,      /* sym_read: read a symbol file into symtab */
 512   pa_symfile_finish,    /* sym_finish: finished with file, cleanup */
 513   pa_symfile_offsets,   /* sym_offsets:  Translate ext. to int. relocation */
 514   NULL                  /* next: pointer to next struct sym_fns */
 515 };
 516
 517 void
 518 _initialize_paread ()
 519 {
 520   add_symtab_fns (&pa_sym_fns);
 521 }