gdb/arch-utils.c

   1 /* Dynamic architecture support for GDB, the GNU debugger.
   2
   3    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   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 2 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,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24
  25 #include "arch-utils.h"
  26 #include "buildsym.h"
  27 #include "gdbcmd.h"
  28 #include "inferior.h"           /* enum CALL_DUMMY_LOCATION et.al. */
  29 #include "gdb_string.h"
  30 #include "regcache.h"
  31 #include "gdb_assert.h"
  32 #include "sim-regno.h"
  33 #include "gdbcore.h"
  34 #include "osabi.h"
  35 #include "target-descriptions.h"
  36
  37 #include "version.h"
  38
  39 #include "floatformat.h"
  40
  41 /* Implementation of extract return value that grubs around in the
  42    register cache.  */
  43 void
  44 legacy_extract_return_value (struct type *type, struct regcache *regcache,
  45                              gdb_byte *valbuf)
  46 {
  47   gdb_byte *registers = deprecated_grub_regcache_for_registers (regcache);
  48   gdb_byte *buf = valbuf;
  49   DEPRECATED_EXTRACT_RETURN_VALUE (type, registers, buf); /* OK */
  50 }
  51
  52 /* Implementation of store return value that grubs the register cache.
  53    Takes a local copy of the buffer to avoid const problems.  */
  54 void
  55 legacy_store_return_value (struct type *type, struct regcache *regcache,
  56                            const gdb_byte *buf)
  57 {
  58   gdb_byte *b = alloca (TYPE_LENGTH (type));
  59   gdb_assert (regcache == current_regcache);
  60   memcpy (b, buf, TYPE_LENGTH (type));
  61   DEPRECATED_STORE_RETURN_VALUE (type, b);
  62 }
  63
  64 int
  65 always_use_struct_convention (int gcc_p, struct type *value_type)
  66 {
  67   return 1;
  68 }
  69
  70 enum return_value_convention
  71 legacy_return_value (struct gdbarch *gdbarch, struct type *valtype,
  72                      struct regcache *regcache, gdb_byte *readbuf,
  73                      const gdb_byte *writebuf)
  74 {
  75   /* NOTE: cagney/2004-06-13: The gcc_p parameter to
  76      USE_STRUCT_CONVENTION isn't used.  */
  77   int struct_return = ((TYPE_CODE (valtype) == TYPE_CODE_STRUCT
  78                         || TYPE_CODE (valtype) == TYPE_CODE_UNION
  79                         || TYPE_CODE (valtype) == TYPE_CODE_ARRAY)
  80                        && DEPRECATED_USE_STRUCT_CONVENTION (0, valtype));
  81
  82   if (writebuf != NULL)
  83     {
  84       gdb_assert (!struct_return);
  85       /* NOTE: cagney/2004-06-13: See stack.c:return_command.  Old
  86          architectures don't expect STORE_RETURN_VALUE to handle small
  87          structures.  Should not be called with such types.  */
  88       gdb_assert (TYPE_CODE (valtype) != TYPE_CODE_STRUCT
  89                   && TYPE_CODE (valtype) != TYPE_CODE_UNION);
  90       STORE_RETURN_VALUE (valtype, regcache, writebuf);
  91     }
  92
  93   if (readbuf != NULL)
  94     {
  95       gdb_assert (!struct_return);
  96       EXTRACT_RETURN_VALUE (valtype, regcache, readbuf);
  97     }
  98
  99   if (struct_return)
 100     return RETURN_VALUE_STRUCT_CONVENTION;
 101   else
 102     return RETURN_VALUE_REGISTER_CONVENTION;
 103 }
 104
 105 int
 106 legacy_register_sim_regno (int regnum)
 107 {
 108   /* Only makes sense to supply raw registers.  */
 109   gdb_assert (regnum >= 0 && regnum < NUM_REGS);
 110   /* NOTE: cagney/2002-05-13: The old code did it this way and it is
 111      suspected that some GDB/SIM combinations may rely on this
 112      behavour.  The default should be one2one_register_sim_regno
 113      (below).  */
 114   if (REGISTER_NAME (regnum) != NULL
 115       && REGISTER_NAME (regnum)[0] != '\0')
 116     return regnum;
 117   else
 118     return LEGACY_SIM_REGNO_IGNORE;
 119 }
 120
 121 CORE_ADDR
 122 generic_skip_trampoline_code (CORE_ADDR pc)
 123 {
 124   return 0;
 125 }
 126
 127 CORE_ADDR
 128 generic_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
 129 {
 130   return 0;
 131 }
 132
 133 int
 134 generic_in_solib_return_trampoline (CORE_ADDR pc, char *name)
 135 {
 136   return 0;
 137 }
 138
 139 int
 140 generic_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 141 {
 142   return 0;
 143 }
 144
 145 void
 146 generic_remote_translate_xfer_address (struct gdbarch *gdbarch,
 147                                        struct regcache *regcache,
 148                                        CORE_ADDR gdb_addr, int gdb_len,
 149                                        CORE_ADDR * rem_addr, int *rem_len)
 150 {
 151   *rem_addr = gdb_addr;
 152   *rem_len = gdb_len;
 153 }
 154
 155 /* Helper functions for INNER_THAN */
 156
 157 int
 158 core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
 159 {
 160   return (lhs < rhs);
 161 }
 162
 163 int
 164 core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
 165 {
 166   return (lhs > rhs);
 167 }
 168
 169
 170 /* Helper functions for TARGET_{FLOAT,DOUBLE}_FORMAT */
 171
 172 const struct floatformat *
 173 default_float_format (struct gdbarch *gdbarch)
 174 {
 175   int byte_order = gdbarch_byte_order (gdbarch);
 176   switch (byte_order)
 177     {
 178     case BFD_ENDIAN_BIG:
 179       return &floatformat_ieee_single_big;
 180     case BFD_ENDIAN_LITTLE:
 181       return &floatformat_ieee_single_little;
 182     default:
 183       internal_error (__FILE__, __LINE__,
 184                       _("default_float_format: bad byte order"));
 185     }
 186 }
 187
 188
 189 const struct floatformat *
 190 default_double_format (struct gdbarch *gdbarch)
 191 {
 192   int byte_order = gdbarch_byte_order (gdbarch);
 193   switch (byte_order)
 194     {
 195     case BFD_ENDIAN_BIG:
 196       return &floatformat_ieee_double_big;
 197     case BFD_ENDIAN_LITTLE:
 198       return &floatformat_ieee_double_little;
 199     default:
 200       internal_error (__FILE__, __LINE__,
 201                       _("default_double_format: bad byte order"));
 202     }
 203 }
 204
 205 /* Misc helper functions for targets. */
 206
 207 CORE_ADDR
 208 core_addr_identity (CORE_ADDR addr)
 209 {
 210   return addr;
 211 }
 212
 213 CORE_ADDR
 214 convert_from_func_ptr_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr,
 215                                      struct target_ops *targ)
 216 {
 217   return addr;
 218 }
 219
 220 int
 221 no_op_reg_to_regnum (int reg)
 222 {
 223   return reg;
 224 }
 225
 226 void
 227 default_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
 228 {
 229   return;
 230 }
 231
 232 void
 233 default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
 234 {
 235   return;
 236 }
 237
 238 int
 239 cannot_register_not (int regnum)
 240 {
 241   return 0;
 242 }
 243
 244 /* Legacy version of target_virtual_frame_pointer().  Assumes that
 245    there is an DEPRECATED_FP_REGNUM and that it is the same, cooked or
 246    raw.  */
 247
 248 void
 249 legacy_virtual_frame_pointer (CORE_ADDR pc,
 250                               int *frame_regnum,
 251                               LONGEST *frame_offset)
 252 {
 253   /* FIXME: cagney/2002-09-13: This code is used when identifying the
 254      frame pointer of the current PC.  It is assuming that a single
 255      register and an offset can determine this.  I think it should
 256      instead generate a byte code expression as that would work better
 257      with things like Dwarf2's CFI.  */
 258   if (DEPRECATED_FP_REGNUM >= 0 && DEPRECATED_FP_REGNUM < NUM_REGS)
 259     *frame_regnum = DEPRECATED_FP_REGNUM;
 260   else if (SP_REGNUM >= 0 && SP_REGNUM < NUM_REGS)
 261     *frame_regnum = SP_REGNUM;
 262   else
 263     /* Should this be an internal error?  I guess so, it is reflecting
 264        an architectural limitation in the current design.  */
 265     internal_error (__FILE__, __LINE__, _("No virtual frame pointer available"));
 266   *frame_offset = 0;
 267 }
 268
 269 /* Assume the world is sane, every register's virtual and real size
 270    is identical.  */
 271
 272 int
 273 generic_register_size (int regnum)
 274 {
 275   gdb_assert (regnum >= 0 && regnum < NUM_REGS + NUM_PSEUDO_REGS);
 276   return TYPE_LENGTH (gdbarch_register_type (current_gdbarch, regnum));
 277 }
 278
 279 /* Assume all registers are adjacent.  */
 280
 281 int
 282 generic_register_byte (int regnum)
 283 {
 284   int byte;
 285   int i;
 286   gdb_assert (regnum >= 0 && regnum < NUM_REGS + NUM_PSEUDO_REGS);
 287   byte = 0;
 288   for (i = 0; i < regnum; i++)
 289     {
 290       byte += generic_register_size (i);
 291     }
 292   return byte;
 293 }
 294
 295 \f
 296 int
 297 legacy_pc_in_sigtramp (CORE_ADDR pc, char *name)
 298 {
 299 #if defined (DEPRECATED_IN_SIGTRAMP)
 300   return DEPRECATED_IN_SIGTRAMP (pc, name);
 301 #else
 302   return name && strcmp ("_sigtramp", name) == 0;
 303 #endif
 304 }
 305
 306 int
 307 generic_convert_register_p (int regnum, struct type *type)
 308 {
 309   return 0;
 310 }
 311
 312 int
 313 default_stabs_argument_has_addr (struct gdbarch *gdbarch, struct type *type)
 314 {
 315   if (DEPRECATED_REG_STRUCT_HAS_ADDR_P ()
 316       && DEPRECATED_REG_STRUCT_HAS_ADDR (processing_gcc_compilation, type))
 317     {
 318       CHECK_TYPEDEF (type);
 319
 320       return (TYPE_CODE (type) == TYPE_CODE_STRUCT
 321               || TYPE_CODE (type) == TYPE_CODE_UNION
 322               || TYPE_CODE (type) == TYPE_CODE_SET
 323               || TYPE_CODE (type) == TYPE_CODE_BITSTRING);
 324     }
 325
 326   return 0;
 327 }
 328
 329 int
 330 generic_instruction_nullified (struct gdbarch *gdbarch,
 331                                struct regcache *regcache)
 332 {
 333   return 0;
 334 }
 335
 336 \f
 337 /* Functions to manipulate the endianness of the target.  */
 338
 339 static int target_byte_order_user = BFD_ENDIAN_UNKNOWN;
 340
 341 static const char endian_big[] = "big";
 342 static const char endian_little[] = "little";
 343 static const char endian_auto[] = "auto";
 344 static const char *endian_enum[] =
 345 {
 346   endian_big,
 347   endian_little,
 348   endian_auto,
 349   NULL,
 350 };
 351 static const char *set_endian_string;
 352
 353 /* Called by ``show endian''.  */
 354
 355 static void
 356 show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 357              const char *value)
 358 {
 359   if (target_byte_order_user != BFD_ENDIAN_UNKNOWN)
 360     if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
 361       fprintf_unfiltered (file, _("The target endianness is set automatically "
 362                                   "(currently big endian)\n"));
 363     else
 364       fprintf_unfiltered (file, _("The target endianness is set automatically "
 365                            "(currently little endian)\n"));
 366   else
 367     if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
 368       fprintf_unfiltered (file,
 369                           _("The target is assumed to be big endian\n"));
 370     else
 371       fprintf_unfiltered (file,
 372                           _("The target is assumed to be little endian\n"));
 373 }
 374
 375 static void
 376 set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 377 {
 378   struct gdbarch_info info;
 379
 380   gdbarch_info_init (&info);
 381
 382   if (set_endian_string == endian_auto)
 383     {
 384       target_byte_order_user = BFD_ENDIAN_UNKNOWN;
 385       if (! gdbarch_update_p (info))
 386         internal_error (__FILE__, __LINE__,
 387                         _("set_endian: architecture update failed"));
 388     }
 389   else if (set_endian_string == endian_little)
 390     {
 391       info.byte_order = BFD_ENDIAN_LITTLE;
 392       if (! gdbarch_update_p (info))
 393         printf_unfiltered (_("Little endian target not supported by GDB\n"));
 394       else
 395         target_byte_order_user = BFD_ENDIAN_LITTLE;
 396     }
 397   else if (set_endian_string == endian_big)
 398     {
 399       info.byte_order = BFD_ENDIAN_BIG;
 400       if (! gdbarch_update_p (info))
 401         printf_unfiltered (_("Big endian target not supported by GDB\n"));
 402       else
 403         target_byte_order_user = BFD_ENDIAN_BIG;
 404     }
 405   else
 406     internal_error (__FILE__, __LINE__,
 407                     _("set_endian: bad value"));
 408
 409   show_endian (gdb_stdout, from_tty, NULL, NULL);
 410 }
 411
 412 /* Given SELECTED, a currently selected BFD architecture, and
 413    FROM_TARGET, a BFD architecture reported by the target description,
 414    return what architecture to use.  Either may be NULL; if both are
 415    specified, we use the more specific.  If the two are obviously
 416    incompatible, warn the user.  */
 417
 418 static const struct bfd_arch_info *
 419 choose_architecture_for_target (const struct bfd_arch_info *selected,
 420                                 const struct bfd_arch_info *from_target)
 421 {
 422   const struct bfd_arch_info *compat1, *compat2;
 423
 424   if (selected == NULL)
 425     return from_target;
 426
 427   if (from_target == NULL)
 428     return selected;
 429
 430   /* struct bfd_arch_info objects are singletons: that is, there's
 431      supposed to be exactly one instance for a given machine.  So you
 432      can tell whether two are equivalent by comparing pointers.  */
 433   if (from_target == selected)
 434     return selected;
 435
 436   /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
 437      incompatible.  But if they are compatible, it returns the 'more
 438      featureful' of the two arches.  That is, if A can run code
 439      written for B, but B can't run code written for A, then it'll
 440      return A.
 441
 442      Some targets (e.g. MIPS as of 2006-12-04) don't fully
 443      implement this, instead always returning NULL or the first
 444      argument.  We detect that case by checking both directions.  */
 445
 446   compat1 = selected->compatible (selected, from_target);
 447   compat2 = from_target->compatible (from_target, selected);
 448
 449   if (compat1 == NULL && compat2 == NULL)
 450     {
 451       warning (_("Selected architecture %s is not compatible "
 452                  "with reported target architecture %s"),
 453                selected->printable_name, from_target->printable_name);
 454       return selected;
 455     }
 456
 457   if (compat1 == NULL)
 458     return compat2;
 459   if (compat2 == NULL)
 460     return compat1;
 461   if (compat1 == compat2)
 462     return compat1;
 463
 464   /* If the two didn't match, but one of them was a default architecture,
 465      assume the more specific one is correct.  This handles the case
 466      where an executable or target description just says "mips", but
 467      the other knows which MIPS variant.  */
 468   if (compat1->the_default)
 469     return compat2;
 470   if (compat2->the_default)
 471     return compat1;
 472
 473   /* We have no idea which one is better.  This is a bug, but not
 474      a critical problem; warn the user.  */
 475   warning (_("Selected architecture %s is ambiguous with "
 476              "reported target architecture %s"),
 477            selected->printable_name, from_target->printable_name);
 478   return selected;
 479 }
 480
 481 /* Functions to manipulate the architecture of the target */
 482
 483 enum set_arch { set_arch_auto, set_arch_manual };
 484
 485 static const struct bfd_arch_info *target_architecture_user;
 486
 487 static const char *set_architecture_string;
 488
 489 const char *
 490 selected_architecture_name (void)
 491 {
 492   if (target_architecture_user == NULL)
 493     return NULL;
 494   else
 495     return set_architecture_string;
 496 }
 497
 498 /* Called if the user enters ``show architecture'' without an
 499    argument. */
 500
 501 static void
 502 show_architecture (struct ui_file *file, int from_tty,
 503                    struct cmd_list_element *c, const char *value)
 504 {
 505   const char *arch;
 506   arch = TARGET_ARCHITECTURE->printable_name;
 507   if (target_architecture_user == NULL)
 508     fprintf_filtered (file, _("\
 509 The target architecture is set automatically (currently %s)\n"), arch);
 510   else
 511     fprintf_filtered (file, _("\
 512 The target architecture is assumed to be %s\n"), arch);
 513 }
 514
 515
 516 /* Called if the user enters ``set architecture'' with or without an
 517    argument. */
 518
 519 static void
 520 set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
 521 {
 522   struct gdbarch_info info;
 523
 524   gdbarch_info_init (&info);
 525
 526   if (strcmp (set_architecture_string, "auto") == 0)
 527     {
 528       target_architecture_user = NULL;
 529       if (!gdbarch_update_p (info))
 530         internal_error (__FILE__, __LINE__,
 531                         _("could not select an architecture automatically"));
 532     }
 533   else
 534     {
 535       info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
 536       if (info.bfd_arch_info == NULL)
 537         internal_error (__FILE__, __LINE__,
 538                         _("set_architecture: bfd_scan_arch failed"));
 539       if (gdbarch_update_p (info))
 540         target_architecture_user = info.bfd_arch_info;
 541       else
 542         printf_unfiltered (_("Architecture `%s' not recognized.\n"),
 543                            set_architecture_string);
 544     }
 545   show_architecture (gdb_stdout, from_tty, NULL, NULL);
 546 }
 547
 548 /* Try to select a global architecture that matches "info".  Return
 549    non-zero if the attempt succeds.  */
 550 int
 551 gdbarch_update_p (struct gdbarch_info info)
 552 {
 553   struct gdbarch *new_gdbarch = gdbarch_find_by_info (info);
 554
 555   /* If there no architecture by that name, reject the request.  */
 556   if (new_gdbarch == NULL)
 557     {
 558       if (gdbarch_debug)
 559         fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 560                             "Architecture not found\n");
 561       return 0;
 562     }
 563
 564   /* If it is the same old architecture, accept the request (but don't
 565      swap anything).  */
 566   if (new_gdbarch == current_gdbarch)
 567     {
 568       if (gdbarch_debug)
 569         fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 570                             "Architecture 0x%08lx (%s) unchanged\n",
 571                             (long) new_gdbarch,
 572                             gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
 573       return 1;
 574     }
 575
 576   /* It's a new architecture, swap it in.  */
 577   if (gdbarch_debug)
 578     fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
 579                         "New architecture 0x%08lx (%s) selected\n",
 580                         (long) new_gdbarch,
 581                         gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
 582   deprecated_current_gdbarch_select_hack (new_gdbarch);
 583
 584   return 1;
 585 }
 586
 587 /* Return the architecture for ABFD.  If no suitable architecture
 588    could be find, return NULL.  */
 589
 590 struct gdbarch *
 591 gdbarch_from_bfd (bfd *abfd)
 592 {
 593   struct gdbarch *old_gdbarch = current_gdbarch;
 594   struct gdbarch *new_gdbarch;
 595   struct gdbarch_info info;
 596
 597   /* If we call gdbarch_find_by_info without filling in info.abfd,
 598      then it will use the global exec_bfd.  That's fine if we don't
 599      have one of those either.  And that's the only time we should
 600      reach here with a NULL ABFD argument - when we are discarding
 601      the executable.  */
 602   gdb_assert (abfd != NULL || exec_bfd == NULL);
 603
 604   gdbarch_info_init (&info);
 605   info.abfd = abfd;
 606   return gdbarch_find_by_info (info);
 607 }
 608
 609 /* Set the dynamic target-system-dependent parameters (architecture,
 610    byte-order) using information found in the BFD */
 611
 612 void
 613 set_gdbarch_from_file (bfd *abfd)
 614 {
 615   struct gdbarch *gdbarch;
 616
 617   gdbarch = gdbarch_from_bfd (abfd);
 618   if (gdbarch == NULL)
 619     error (_("Architecture of file not recognized."));
 620   deprecated_current_gdbarch_select_hack (gdbarch);
 621 }
 622
 623 /* Initialize the current architecture.  Update the ``set
 624    architecture'' command so that it specifies a list of valid
 625    architectures.  */
 626
 627 #ifdef DEFAULT_BFD_ARCH
 628 extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
 629 static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
 630 #else
 631 static const bfd_arch_info_type *default_bfd_arch;
 632 #endif
 633
 634 #ifdef DEFAULT_BFD_VEC
 635 extern const bfd_target DEFAULT_BFD_VEC;
 636 static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
 637 #else
 638 static const bfd_target *default_bfd_vec;
 639 #endif
 640
 641 static int default_byte_order = BFD_ENDIAN_UNKNOWN;
 642
 643 void
 644 initialize_current_architecture (void)
 645 {
 646   const char **arches = gdbarch_printable_names ();
 647
 648   /* determine a default architecture and byte order. */
 649   struct gdbarch_info info;
 650   gdbarch_info_init (&info);
 651
 652   /* Find a default architecture. */
 653   if (default_bfd_arch == NULL)
 654     {
 655       /* Choose the architecture by taking the first one
 656          alphabetically. */
 657       const char *chosen = arches[0];
 658       const char **arch;
 659       for (arch = arches; *arch != NULL; arch++)
 660         {
 661           if (strcmp (*arch, chosen) < 0)
 662             chosen = *arch;
 663         }
 664       if (chosen == NULL)
 665         internal_error (__FILE__, __LINE__,
 666                         _("initialize_current_architecture: No arch"));
 667       default_bfd_arch = bfd_scan_arch (chosen);
 668       if (default_bfd_arch == NULL)
 669         internal_error (__FILE__, __LINE__,
 670                         _("initialize_current_architecture: Arch not found"));
 671     }
 672
 673   info.bfd_arch_info = default_bfd_arch;
 674
 675   /* Take several guesses at a byte order.  */
 676   if (default_byte_order == BFD_ENDIAN_UNKNOWN
 677       && default_bfd_vec != NULL)
 678     {
 679       /* Extract BFD's default vector's byte order. */
 680       switch (default_bfd_vec->byteorder)
 681         {
 682         case BFD_ENDIAN_BIG:
 683           default_byte_order = BFD_ENDIAN_BIG;
 684           break;
 685         case BFD_ENDIAN_LITTLE:
 686           default_byte_order = BFD_ENDIAN_LITTLE;
 687           break;
 688         default:
 689           break;
 690         }
 691     }
 692   if (default_byte_order == BFD_ENDIAN_UNKNOWN)
 693     {
 694       /* look for ``*el-*'' in the target name. */
 695       const char *chp;
 696       chp = strchr (target_name, '-');
 697       if (chp != NULL
 698           && chp - 2 >= target_name
 699           && strncmp (chp - 2, "el", 2) == 0)
 700         default_byte_order = BFD_ENDIAN_LITTLE;
 701     }
 702   if (default_byte_order == BFD_ENDIAN_UNKNOWN)
 703     {
 704       /* Wire it to big-endian!!! */
 705       default_byte_order = BFD_ENDIAN_BIG;
 706     }
 707
 708   info.byte_order = default_byte_order;
 709
 710   if (! gdbarch_update_p (info))
 711     internal_error (__FILE__, __LINE__,
 712                     _("initialize_current_architecture: Selection of "
 713                       "initial architecture failed"));
 714
 715   /* Create the ``set architecture'' command appending ``auto'' to the
 716      list of architectures. */
 717   {
 718     struct cmd_list_element *c;
 719     /* Append ``auto''. */
 720     int nr;
 721     for (nr = 0; arches[nr] != NULL; nr++);
 722     arches = xrealloc (arches, sizeof (char*) * (nr + 2));
 723     arches[nr + 0] = "auto";
 724     arches[nr + 1] = NULL;
 725     add_setshow_enum_cmd ("architecture", class_support,
 726                           arches, &set_architecture_string, _("\
 727 Set architecture of target."), _("\
 728 Show architecture of target."), NULL,
 729                           set_architecture, show_architecture,
 730                           &setlist, &showlist);
 731     add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
 732   }
 733 }
 734
 735
 736 /* Initialize a gdbarch info to values that will be automatically
 737    overridden.  Note: Originally, this ``struct info'' was initialized
 738    using memset(0).  Unfortunately, that ran into problems, namely
 739    BFD_ENDIAN_BIG is zero.  An explicit initialization function that
 740    can explicitly set each field to a well defined value is used.  */
 741
 742 void
 743 gdbarch_info_init (struct gdbarch_info *info)
 744 {
 745   memset (info, 0, sizeof (struct gdbarch_info));
 746   info->byte_order = BFD_ENDIAN_UNKNOWN;
 747   info->osabi = GDB_OSABI_UNINITIALIZED;
 748 }
 749
 750 /* Similar to init, but this time fill in the blanks.  Information is
 751    obtained from the global "set ..." options and explicitly
 752    initialized INFO fields.  */
 753
 754 void
 755 gdbarch_info_fill (struct gdbarch_info *info)
 756 {
 757   /* Check for the current file.  */
 758   if (info->abfd == NULL)
 759     info->abfd = exec_bfd;
 760
 761   /* Check for the current target description.  */
 762   if (info->target_desc == NULL)
 763     info->target_desc = target_current_description ();
 764
 765   /* "(gdb) set architecture ...".  */
 766   if (info->bfd_arch_info == NULL
 767       && target_architecture_user)
 768     info->bfd_arch_info = target_architecture_user;
 769   /* From the file.  */
 770   if (info->bfd_arch_info == NULL
 771       && info->abfd != NULL
 772       && bfd_get_arch (info->abfd) != bfd_arch_unknown
 773       && bfd_get_arch (info->abfd) != bfd_arch_obscure)
 774     info->bfd_arch_info = bfd_get_arch_info (info->abfd);
 775   /* From the target.  */
 776   if (info->target_desc != NULL)
 777     info->bfd_arch_info = choose_architecture_for_target
 778       (info->bfd_arch_info, tdesc_architecture (info->target_desc));
 779   /* From the default.  */
 780   if (info->bfd_arch_info == NULL)
 781     info->bfd_arch_info = default_bfd_arch;
 782
 783   /* "(gdb) set byte-order ...".  */
 784   if (info->byte_order == BFD_ENDIAN_UNKNOWN
 785       && target_byte_order_user != BFD_ENDIAN_UNKNOWN)
 786     info->byte_order = target_byte_order_user;
 787   /* From the INFO struct.  */
 788   if (info->byte_order == BFD_ENDIAN_UNKNOWN
 789       && info->abfd != NULL)
 790     info->byte_order = (bfd_big_endian (info->abfd) ? BFD_ENDIAN_BIG
 791                         : bfd_little_endian (info->abfd) ? BFD_ENDIAN_LITTLE
 792                         : BFD_ENDIAN_UNKNOWN);
 793   /* From the default.  */
 794   if (info->byte_order == BFD_ENDIAN_UNKNOWN)
 795     info->byte_order = default_byte_order;
 796
 797   /* "(gdb) set osabi ...".  Handled by gdbarch_lookup_osabi.  */
 798   if (info->osabi == GDB_OSABI_UNINITIALIZED)
 799     info->osabi = gdbarch_lookup_osabi (info->abfd);
 800
 801   /* Must have at least filled in the architecture.  */
 802   gdb_assert (info->bfd_arch_info != NULL);
 803 }
 804
 805 /* */
 806
 807 extern initialize_file_ftype _initialize_gdbarch_utils; /* -Wmissing-prototypes */
 808
 809 void
 810 _initialize_gdbarch_utils (void)
 811 {
 812   struct cmd_list_element *c;
 813   add_setshow_enum_cmd ("endian", class_support,
 814                         endian_enum, &set_endian_string, _("\
 815 Set endianness of target."), _("\
 816 Show endianness of target."), NULL,
 817                         set_endian, show_endian,
 818                         &setlist, &showlist);
 819 }