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 "libhppa.h"
  28 #include <syms.h>
  29 #include "symtab.h"
  30 #include "symfile.h"
  31 #include "objfiles.h"
  32 #include "buildsym.h"
  33 #include "stabsread.h"
  34 #include "gdb-stabs.h"
  35 #include "complaints.h"
  36 #include <string.h>
  37 #include "demangle.h"
  38 #include <sys/file.h>
  39
  40 /* Size of n_value and n_strx fields in a stab symbol.  */
  41 #define BYTES_IN_WORD 4
  42
  43 #include "aout/aout64.h"
  44
  45 /* Various things we might complain about... */
  46
  47 static void
  48 pa_symfile_init PARAMS ((struct objfile *));
  49
  50 static void
  51 pa_new_init PARAMS ((struct objfile *));
  52
  53 static void
  54 read_unwind_info PARAMS ((struct objfile *));
  55
  56 static void
  57 pa_symfile_read PARAMS ((struct objfile *, struct section_offsets *, int));
  58
  59 static void
  60 pa_symfile_finish PARAMS ((struct objfile *));
  61
  62 static void
  63 pa_symtab_read PARAMS ((bfd *,  CORE_ADDR, struct objfile *));
  64
  65 static void
  66 free_painfo PARAMS ((PTR));
  67
  68 static struct section_offsets *
  69 pa_symfile_offsets PARAMS ((struct objfile *, CORE_ADDR));
  70
  71 static void
  72 record_minimal_symbol PARAMS ((char *, CORE_ADDR,
  73                                enum minimal_symbol_type,
  74                                struct objfile *));
  75
  76 static void
  77 record_minimal_symbol (name, address, ms_type, objfile)
  78      char *name;
  79      CORE_ADDR address;
  80      enum minimal_symbol_type ms_type;
  81      struct objfile *objfile;
  82 {
  83   name = obsavestring (name, strlen (name), &objfile -> symbol_obstack);
  84   prim_record_minimal_symbol (name, address, ms_type);
  85 }
  86
  87 /*
  88
  89 LOCAL FUNCTION
  90
  91         pa_symtab_read -- read the symbol table of a PA file
  92
  93 SYNOPSIS
  94
  95         void pa_symtab_read (bfd *abfd, CORE_ADDR addr,
  96                               struct objfile *objfile)
  97
  98 DESCRIPTION
  99
 100         Given an open bfd, a base address to relocate symbols to, and a
 101         flag that specifies whether or not this bfd is for an executable
 102         or not (may be shared library for example), add all the global
 103         function and data symbols to the minimal symbol table.
 104 */
 105
 106 static void
 107 pa_symtab_read (abfd, addr, objfile)
 108      bfd *abfd;
 109      CORE_ADDR addr;
 110      struct objfile *objfile;
 111 {
 112   unsigned int number_of_symbols;
 113   unsigned int i;
 114   int val;
 115   char *stringtab;
 116   struct symbol_dictionary_record *buf, *bufp, *endbufp;
 117   char *symname;
 118   CONST int symsize = sizeof (struct symbol_dictionary_record);
 119
 120   number_of_symbols = bfd_get_symcount (abfd);
 121
 122   buf = alloca (symsize * number_of_symbols);
 123   bfd_seek (abfd, obj_som_sym_filepos (abfd), L_SET);
 124   val = bfd_read (buf, symsize * number_of_symbols, 1, abfd);
 125   if (val != symsize * number_of_symbols)
 126     error ("Couldn't read symbol dictionary!");
 127
 128   stringtab = alloca (obj_som_stringtab_size (abfd));
 129   bfd_seek (abfd, obj_som_str_filepos (abfd), L_SET);
 130   val = bfd_read (stringtab, obj_som_stringtab_size (abfd), 1, abfd);
 131   if (val != obj_som_stringtab_size (abfd))
 132     error ("Can't read in HP string table.");
 133
 134   endbufp = buf + number_of_symbols;
 135   for (bufp = buf; bufp < endbufp; ++bufp)
 136     {
 137       enum minimal_symbol_type ms_type;
 138
 139       QUIT;
 140
 141       switch (bufp->symbol_scope)
 142         {
 143         case SS_UNIVERSAL:
 144           switch (bufp->symbol_type)
 145             {
 146             case ST_SYM_EXT:
 147             case ST_ARG_EXT:
 148               continue;
 149
 150             case ST_CODE:
 151             case ST_PRI_PROG:
 152             case ST_SEC_PROG:
 153             case ST_ENTRY:
 154             case ST_MILLICODE:
 155               symname = bufp->name.n_strx + stringtab;
 156               ms_type = mst_text;
 157               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 158               break;
 159             case ST_DATA:
 160               symname = bufp->name.n_strx + stringtab;
 161               ms_type = mst_data;
 162               break;
 163             default:
 164               continue;
 165             }
 166           break;
 167
 168 #if 0
 169           /* SS_GLOBAL and SS_LOCAL are two names for the same thing (!).  */
 170         case SS_GLOBAL:
 171 #endif
 172         case SS_LOCAL:
 173           switch (bufp->symbol_type)
 174             {
 175             case ST_SYM_EXT:
 176             case ST_ARG_EXT:
 177               continue;
 178
 179             case ST_CODE:
 180               symname = bufp->name.n_strx + stringtab;
 181               ms_type = mst_file_text;
 182               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 183
 184             check_strange_names:
 185               /* GAS leaves symbols with the prefixes "LS$", "LBB$",
 186                  and "LBE$" in .o files after assembling.  And thus
 187                  they appear in the final executable.  This can
 188                  cause problems if these special symbols have the
 189                  same value as real symbols.  So ignore them.  Also "LC$".  */
 190               if (*symname == 'L'
 191                   && (symname[2] == '$' || symname[3] == '$'))
 192                 continue;
 193               break;
 194
 195             case ST_PRI_PROG:
 196             case ST_SEC_PROG:
 197             case ST_ENTRY:
 198             case ST_MILLICODE:
 199               symname = bufp->name.n_strx + stringtab;
 200               ms_type = mst_file_text;
 201               bufp->symbol_value &= ~0x3; /* clear out permission bits */
 202               break;
 203
 204             case ST_DATA:
 205               symname = bufp->name.n_strx + stringtab;
 206               ms_type = mst_file_data;
 207               goto check_strange_names;
 208
 209             default:
 210               continue;
 211             }
 212           break;
 213
 214         default:
 215           continue;
 216         }
 217
 218       if (bufp->name.n_strx > obj_som_stringtab_size (abfd))
 219         error ("Invalid symbol data; bad HP string table offset: %d",
 220                bufp->name.n_strx);
 221
 222       record_minimal_symbol (symname,
 223                              bufp->symbol_value, ms_type,
 224                              objfile);
 225     }
 226
 227   install_minimal_symbols (objfile);
 228 }
 229
 230 /* Read in the backtrace information stored in the `$UNWIND_START$' section of
 231    the object file.  This info is used mainly by find_unwind_entry() to find
 232    out the stack frame size and frame pointer used by procedures.  We put
 233    everything on the psymbol obstack in the objfile so that it automatically
 234    gets freed when the objfile is destroyed.  */
 235
 236 static void
 237 read_unwind_info (objfile)
 238      struct objfile *objfile;
 239 {
 240   asection *unwind_sec;
 241   struct obj_unwind_info *ui;
 242
 243   ui = obstack_alloc (&objfile->psymbol_obstack,
 244                       sizeof (struct obj_unwind_info));
 245
 246   ui->table = NULL;
 247   ui->cache = NULL;
 248   ui->last = -1;
 249
 250   unwind_sec = bfd_get_section_by_name (objfile->obfd,
 251                                         "$UNWIND_START$");
 252   if (unwind_sec)
 253     {
 254       int size;
 255       int i, *ip;
 256
 257       size = bfd_section_size (objfile->obfd, unwind_sec);
 258       ui->table = obstack_alloc (&objfile->psymbol_obstack, size);
 259       ui->last = size / sizeof (struct unwind_table_entry) - 1;
 260
 261       bfd_get_section_contents (objfile->obfd, unwind_sec, ui->table,
 262                                 0, size);
 263
 264       OBJ_UNWIND_INFO (objfile) = ui;
 265     }
 266 }
 267
 268 /* Scan and build partial symbols for a symbol file.
 269    We have been initialized by a call to pa_symfile_init, which
 270    currently does nothing.
 271
 272    SECTION_OFFSETS is a set of offsets to apply to relocate the symbols
 273    in each section.  This is ignored, as it isn't needed for the PA.
 274
 275    MAINLINE is true if we are reading the main symbol
 276    table (as opposed to a shared lib or dynamically loaded file).
 277
 278    This function only does the minimum work necessary for letting the
 279    user "name" things symbolically; it does not read the entire symtab.
 280    Instead, it reads the external and static symbols and puts them in partial
 281    symbol tables.  When more extensive information is requested of a
 282    file, the corresponding partial symbol table is mutated into a full
 283    fledged symbol table by going back and reading the symbols
 284    for real.
 285
 286    We look for sections with specific names, to tell us what debug
 287    format to look for:  FIXME!!!
 288
 289    pastab_build_psymtabs() handles STABS symbols.
 290
 291    Note that PA files have a "minimal" symbol table, which is vaguely
 292    reminiscent of a COFF symbol table, but has only the minimal information
 293    necessary for linking.  We process this also, and use the information to
 294    build gdb's minimal symbol table.  This gives us some minimal debugging
 295    capability even for files compiled without -g.  */
 296
 297 static void
 298 pa_symfile_read (objfile, section_offsets, mainline)
 299      struct objfile *objfile;
 300      struct section_offsets *section_offsets;
 301      int mainline;
 302 {
 303   bfd *abfd = objfile->obfd;
 304   struct cleanup *back_to;
 305   CORE_ADDR offset;
 306
 307   init_minimal_symbol_collection ();
 308   back_to = make_cleanup (discard_minimal_symbols, 0);
 309
 310   make_cleanup (free_painfo, (PTR) objfile);
 311
 312   /* Process the normal PA symbol table first. */
 313
 314   /* FIXME, should take a section_offsets param, not just an offset.  */
 315
 316   offset = ANOFFSET (section_offsets, 0);
 317   pa_symtab_read (abfd, offset, objfile);
 318
 319   /* Now process debugging information, which is contained in
 320      special PA sections.  */
 321
 322   pastab_build_psymtabs (objfile, section_offsets, mainline);
 323
 324   read_unwind_info(objfile);
 325
 326   do_cleanups (back_to);
 327 }
 328
 329 /* This cleans up the objfile's sym_stab_info pointer, and the chain of
 330    stab_section_info's, that might be dangling from it.  */
 331
 332 static void
 333 free_painfo (objp)
 334      PTR objp;
 335 {
 336   struct objfile *objfile = (struct objfile *)objp;
 337   struct dbx_symfile_info *dbxinfo = (struct dbx_symfile_info *)
 338                                      objfile->sym_stab_info;
 339   struct stab_section_info *ssi, *nssi;
 340
 341   ssi = dbxinfo->stab_section_info;
 342   while (ssi)
 343     {
 344       nssi = ssi->next;
 345       mfree (objfile->md, ssi);
 346       ssi = nssi;
 347     }
 348
 349   dbxinfo->stab_section_info = 0;       /* Just say No mo info about this.  */
 350 }
 351
 352 /* Initialize anything that needs initializing when a completely new symbol
 353    file is specified (not just adding some symbols from another file, e.g. a
 354    shared library).
 355
 356    We reinitialize buildsym, since we may be reading stabs from a PA file.  */
 357
 358 static void
 359 pa_new_init (ignore)
 360      struct objfile *ignore;
 361 {
 362   stabsread_new_init ();
 363   buildsym_new_init ();
 364 }
 365
 366 /* Perform any local cleanups required when we are done with a particular
 367    objfile.  I.E, we are in the process of discarding all symbol information
 368    for an objfile, freeing up all memory held for it, and unlinking the
 369    objfile struct from the global list of known objfiles. */
 370
 371 static void
 372 pa_symfile_finish (objfile)
 373      struct objfile *objfile;
 374 {
 375   if (objfile -> sym_stab_info != NULL)
 376     {
 377       mfree (objfile -> md, objfile -> sym_stab_info);
 378     }
 379 }
 380
 381 /* PA specific initialization routine for reading symbols.
 382
 383    It is passed a pointer to a struct sym_fns which contains, among other
 384    things, the BFD for the file whose symbols are being read, and a slot for
 385    a pointer to "private data" which we can fill with goodies.
 386
 387    This routine is almost a complete ripoff of dbx_symfile_init.  The
 388    common parts of these routines should be extracted and used instead of
 389    duplicating this code.  FIXME. */
 390
 391 static void
 392 pa_symfile_init (objfile)
 393      struct objfile *objfile;
 394 {
 395   int val;
 396   bfd *sym_bfd = objfile->obfd;
 397   char *name = bfd_get_filename (sym_bfd);
 398   asection *stabsect;           /* Section containing symbol table entries */
 399   asection *stringsect;         /* Section containing symbol name strings */
 400
 401   stabsect = bfd_get_section_by_name (sym_bfd, "$GDB_SYMBOLS$");
 402   stringsect = bfd_get_section_by_name (sym_bfd, "$GDB_STRINGS$");
 403
 404   /* Allocate struct to keep track of the symfile */
 405   objfile->sym_stab_info = (PTR)
 406     xmmalloc (objfile -> md, sizeof (struct dbx_symfile_info));
 407
 408   memset ((PTR) objfile->sym_stab_info, 0, sizeof (struct dbx_symfile_info));
 409
 410   if (!stabsect)
 411     return;
 412
 413   if (!stringsect)
 414     error ("Found stabs, but not string section");
 415
 416   /* FIXME POKING INSIDE BFD DATA STRUCTURES */
 417 #define STRING_TABLE_OFFSET     (stringsect->filepos)
 418 #define SYMBOL_TABLE_OFFSET     (stabsect->filepos)
 419
 420   /* FIXME POKING INSIDE BFD DATA STRUCTURES */
 421
 422   DBX_SYMFILE_INFO (objfile)->stab_section_info = NULL;
 423   DBX_TEXT_SECT (objfile) = bfd_get_section_by_name (sym_bfd, ".text");
 424   if (!DBX_TEXT_SECT (objfile))
 425     error ("Can't find .text section in symbol file");
 426
 427   /* FIXME: I suspect this should be external_nlist.  The size of host
 428      types like long and bfd_vma should not affect how we read the
 429      file.  */
 430   DBX_SYMBOL_SIZE (objfile) = sizeof (struct internal_nlist);
 431   DBX_SYMCOUNT (objfile) = bfd_section_size (sym_bfd, stabsect)
 432     / DBX_SYMBOL_SIZE (objfile);
 433   DBX_SYMTAB_OFFSET (objfile) = SYMBOL_TABLE_OFFSET;
 434
 435   /* Read the string table and stash it away in the psymbol_obstack.  It is
 436      only needed as long as we need to expand psymbols into full symbols,
 437      so when we blow away the psymbol the string table goes away as well.
 438      Note that gdb used to use the results of attempting to malloc the
 439      string table, based on the size it read, as a form of sanity check
 440      for botched byte swapping, on the theory that a byte swapped string
 441      table size would be so totally bogus that the malloc would fail.  Now
 442      that we put in on the psymbol_obstack, we can't do this since gdb gets
 443      a fatal error (out of virtual memory) if the size is bogus.  We can
 444      however at least check to see if the size is zero or some negative
 445      value. */
 446
 447   DBX_STRINGTAB_SIZE (objfile) = bfd_section_size (sym_bfd, stringsect);
 448
 449   if (DBX_SYMCOUNT (objfile) == 0
 450       || DBX_STRINGTAB_SIZE (objfile) == 0)
 451     return;
 452
 453   if (DBX_STRINGTAB_SIZE (objfile) <= 0
 454       || DBX_STRINGTAB_SIZE (objfile) > bfd_get_size (sym_bfd))
 455     error ("ridiculous string table size (%d bytes).",
 456            DBX_STRINGTAB_SIZE (objfile));
 457
 458   DBX_STRINGTAB (objfile) =
 459     (char *) obstack_alloc (&objfile -> psymbol_obstack,
 460                             DBX_STRINGTAB_SIZE (objfile));
 461
 462   /* Now read in the string table in one big gulp.  */
 463
 464   val = bfd_seek (sym_bfd, STRING_TABLE_OFFSET, L_SET);
 465   if (val < 0)
 466     perror_with_name (name);
 467   val = bfd_read (DBX_STRINGTAB (objfile), DBX_STRINGTAB_SIZE (objfile), 1,
 468                   sym_bfd);
 469   if (val == 0)
 470     error ("End of file reading string table");
 471   else if (val < 0)
 472     /* It's possible bfd_read should be setting bfd_error, and we should be
 473        checking that.  But currently it doesn't set bfd_error.  */
 474     perror_with_name (name);
 475   else if (val != DBX_STRINGTAB_SIZE (objfile))
 476     error ("Short read reading string table");
 477 }
 478
 479 /* PA specific parsing routine for section offsets.
 480
 481    Plain and simple for now.  */
 482
 483 static struct section_offsets *
 484 pa_symfile_offsets (objfile, addr)
 485      struct objfile *objfile;
 486      CORE_ADDR addr;
 487 {
 488   struct section_offsets *section_offsets;
 489   int i;
 490
 491   objfile->num_sections = SECT_OFF_MAX;
 492   section_offsets = (struct section_offsets *)
 493     obstack_alloc (&objfile -> psymbol_obstack,
 494                    sizeof (struct section_offsets)
 495                    + sizeof (section_offsets->offsets) * (SECT_OFF_MAX-1));
 496
 497   for (i = 0; i < SECT_OFF_MAX; i++)
 498     ANOFFSET (section_offsets, i) = addr;
 499
 500   return section_offsets;
 501 }
 502 \f
 503 /* Register that we are able to handle SOM object file formats (does this
 504    work for hp300, or just PA?  I suspect the latter).  */
 505
 506 static struct sym_fns pa_sym_fns =
 507 {
 508   "som",                /* sym_name: name or name prefix of BFD target type */
 509   3,                    /* sym_namelen: number of significant sym_name chars */
 510   pa_new_init,          /* sym_new_init: init anything gbl to entire symtab */
 511   pa_symfile_init,      /* sym_init: read initial info, setup for sym_read() */
 512   pa_symfile_read,      /* sym_read: read a symbol file into symtab */
 513   pa_symfile_finish,    /* sym_finish: finished with file, cleanup */
 514   pa_symfile_offsets,   /* sym_offsets:  Translate ext. to int. relocation */
 515   NULL                  /* next: pointer to next struct sym_fns */
 516 };
 517
 518 void
 519 _initialize_paread ()
 520 {
 521   add_symtab_fns (&pa_sym_fns);
 522 }