gdb/arch-utils.c

   1 /* Dynamic architecture support for GDB, the GNU debugger.
   2    Copyright 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22
  23 #if GDB_MULTI_ARCH
  24 #include "gdbcmd.h"
  25 #include "inferior.h"           /* enum CALL_DUMMY_LOCATION et.al. */
  26 #else
  27 /* Just include everything in sight so that the every old definition
  28    of macro is visible. */
  29 #include "gdb_string.h"
  30 #include "symtab.h"
  31 #include "frame.h"
  32 #include "inferior.h"
  33 #include "breakpoint.h"
  34 #include "gdb_wait.h"
  35 #include "gdbcore.h"
  36 #include "gdbcmd.h"
  37 #include "target.h"
  38 #include "annotate.h"
  39 #endif
  40 #include "regcache.h"
  41 #include "gdb_assert.h"
  42
  43 #include "version.h"
  44
  45 #include "floatformat.h"
  46
  47 /* Use the program counter to determine the contents and size
  48    of a breakpoint instruction.  If no target-dependent macro
  49    BREAKPOINT_FROM_PC has been defined to implement this function,
  50    assume that the breakpoint doesn't depend on the PC, and
  51    use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros.
  52    Return a pointer to a string of bytes that encode a breakpoint
  53    instruction, stores the length of the string to *lenptr,
  54    and optionally adjust the pc to point to the correct memory location
  55    for inserting the breakpoint.  */
  56
  57 unsigned char *
  58 legacy_breakpoint_from_pc (CORE_ADDR * pcptr, int *lenptr)
  59 {
  60   /* {BIG_,LITTLE_}BREAKPOINT is the sequence of bytes we insert for a
  61      breakpoint.  On some machines, breakpoints are handled by the
  62      target environment and we don't have to worry about them here.  */
  63 #ifdef BIG_BREAKPOINT
  64   if (TARGET_BYTE_ORDER == BIG_ENDIAN)
  65     {
  66       static unsigned char big_break_insn[] = BIG_BREAKPOINT;
  67       *lenptr = sizeof (big_break_insn);
  68       return big_break_insn;
  69     }
  70 #endif
  71 #ifdef LITTLE_BREAKPOINT
  72   if (TARGET_BYTE_ORDER != BIG_ENDIAN)
  73     {
  74       static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
  75       *lenptr = sizeof (little_break_insn);
  76       return little_break_insn;
  77     }
  78 #endif
  79 #ifdef BREAKPOINT
  80   {
  81     static unsigned char break_insn[] = BREAKPOINT;
  82     *lenptr = sizeof (break_insn);
  83     return break_insn;
  84   }
  85 #endif
  86   *lenptr = 0;
  87   return NULL;
  88 }
  89
  90 int
  91 generic_frameless_function_invocation_not (struct frame_info *fi)
  92 {
  93   return 0;
  94 }
  95
  96 int
  97 generic_return_value_on_stack_not (struct type *type)
  98 {
  99   return 0;
 100 }
 101
 102 CORE_ADDR
 103 generic_skip_trampoline_code (CORE_ADDR pc)
 104 {
 105   return 0;
 106 }
 107
 108 int
 109 generic_in_solib_call_trampoline (CORE_ADDR pc, char *name)
 110 {
 111   return 0;
 112 }
 113
 114 char *
 115 legacy_register_name (int i)
 116 {
 117 #ifdef REGISTER_NAMES
 118   static char *names[] = REGISTER_NAMES;
 119   if (i < 0 || i >= (sizeof (names) / sizeof (*names)))
 120     return NULL;
 121   else
 122     return names[i];
 123 #else
 124   internal_error (__FILE__, __LINE__,
 125                   "legacy_register_name: called.");
 126   return NULL;
 127 #endif
 128 }
 129
 130 #if defined (CALL_DUMMY)
 131 LONGEST legacy_call_dummy_words[] = CALL_DUMMY;
 132 #else
 133 LONGEST legacy_call_dummy_words[1];
 134 #endif
 135 int legacy_sizeof_call_dummy_words = sizeof (legacy_call_dummy_words);
 136
 137 void
 138 generic_remote_translate_xfer_address (CORE_ADDR gdb_addr, int gdb_len,
 139                                        CORE_ADDR * rem_addr, int *rem_len)
 140 {
 141   *rem_addr = gdb_addr;
 142   *rem_len = gdb_len;
 143 }
 144
 145 int
 146 generic_prologue_frameless_p (CORE_ADDR ip)
 147 {
 148 #ifdef SKIP_PROLOGUE_FRAMELESS_P
 149   return ip == SKIP_PROLOGUE_FRAMELESS_P (ip);
 150 #else
 151   return ip == SKIP_PROLOGUE (ip);
 152 #endif
 153 }
 154
 155 /* New/multi-arched targets should use the correct gdbarch field
 156    instead of using this global pointer. */
 157 int
 158 legacy_print_insn (bfd_vma vma, disassemble_info *info)
 159 {
 160   return (*tm_print_insn) (vma, info);
 161 }
 162
 163 /* Helper functions for INNER_THAN */
 164
 165 int
 166 core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
 167 {
 168   return (lhs < rhs);
 169 }
 170
 171 int
 172 core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
 173 {
 174   return (lhs > rhs);
 175 }
 176
 177
 178 /* Helper functions for TARGET_{FLOAT,DOUBLE}_FORMAT */
 179
 180 const struct floatformat *
 181 default_float_format (struct gdbarch *gdbarch)
 182 {
 183 #if GDB_MULTI_ARCH
 184   int byte_order = gdbarch_byte_order (gdbarch);
 185 #else
 186   int byte_order = TARGET_BYTE_ORDER;
 187 #endif
 188   switch (byte_order)
 189     {
 190     case BIG_ENDIAN:
 191       return &floatformat_ieee_single_big;
 192     case LITTLE_ENDIAN:
 193       return &floatformat_ieee_single_little;
 194     default:
 195       internal_error (__FILE__, __LINE__,
 196                       "default_float_format: bad byte order");
 197     }
 198 }
 199
 200
 201 const struct floatformat *
 202 default_double_format (struct gdbarch *gdbarch)
 203 {
 204 #if GDB_MULTI_ARCH
 205   int byte_order = gdbarch_byte_order (gdbarch);
 206 #else
 207   int byte_order = TARGET_BYTE_ORDER;
 208 #endif
 209   switch (byte_order)
 210     {
 211     case BIG_ENDIAN:
 212       return &floatformat_ieee_double_big;
 213     case LITTLE_ENDIAN:
 214       return &floatformat_ieee_double_little;
 215     default:
 216       internal_error (__FILE__, __LINE__,
 217                       "default_double_format: bad byte order");
 218     }
 219 }
 220
 221 /* Misc helper functions for targets. */
 222
 223 int
 224 frame_num_args_unknown (struct frame_info *fi)
 225 {
 226   return -1;
 227 }
 228
 229
 230 int
 231 generic_register_convertible_not (int num)
 232 {
 233   return 0;
 234 }
 235
 236
 237 int
 238 default_register_sim_regno (int num)
 239 {
 240   return num;
 241 }
 242
 243
 244 CORE_ADDR
 245 core_addr_identity (CORE_ADDR addr)
 246 {
 247   return addr;
 248 }
 249
 250 int
 251 no_op_reg_to_regnum (int reg)
 252 {
 253   return reg;
 254 }
 255
 256 /* For use by frame_args_address and frame_locals_address.  */
 257 CORE_ADDR
 258 default_frame_address (struct frame_info *fi)
 259 {
 260   return fi->frame;
 261 }
 262
 263 /* Default prepare_to_procced().  */
 264 int
 265 default_prepare_to_proceed (int select_it)
 266 {
 267   return 0;
 268 }
 269
 270 /* Generic prepare_to_proceed().  This one should be suitable for most
 271    targets that support threads. */
 272 int
 273 generic_prepare_to_proceed (int select_it)
 274 {
 275   ptid_t wait_ptid;
 276   struct target_waitstatus wait_status;
 277
 278   /* Get the last target status returned by target_wait().  */
 279   get_last_target_status (&wait_ptid, &wait_status);
 280
 281   /* Make sure we were stopped either at a breakpoint, or because
 282      of a Ctrl-C.  */
 283   if (wait_status.kind != TARGET_WAITKIND_STOPPED
 284       || (wait_status.value.sig != TARGET_SIGNAL_TRAP &&
 285           wait_status.value.sig != TARGET_SIGNAL_INT))
 286     {
 287       return 0;
 288     }
 289
 290   if (!ptid_equal (wait_ptid, minus_one_ptid)
 291       && !ptid_equal (inferior_ptid, wait_ptid))
 292     {
 293       /* Switched over from WAIT_PID.  */
 294       CORE_ADDR wait_pc = read_pc_pid (wait_ptid);
 295
 296       if (wait_pc != read_pc ())
 297         {
 298           if (select_it)
 299             {
 300               /* Switch back to WAIT_PID thread.  */
 301               inferior_ptid = wait_ptid;
 302
 303               /* FIXME: This stuff came from switch_to_thread() in
 304                  thread.c (which should probably be a public function).  */
 305               flush_cached_frames ();
 306               registers_changed ();
 307               stop_pc = wait_pc;
 308               select_frame (get_current_frame (), 0);
 309             }
 310           /* We return 1 to indicate that there is a breakpoint here,
 311              so we need to step over it before continuing to avoid
 312              hitting it straight away. */
 313           if (breakpoint_here_p (wait_pc))
 314             {
 315               return 1;
 316             }
 317         }
 318     }
 319   return 0;
 320
 321 }
 322
 323 void
 324 init_frame_pc_noop (int fromleaf, struct frame_info *prev)
 325 {
 326   return;
 327 }
 328
 329 void
 330 init_frame_pc_default (int fromleaf, struct frame_info *prev)
 331 {
 332   if (fromleaf)
 333     prev->pc = SAVED_PC_AFTER_CALL (prev->next);
 334   else if (prev->next != NULL)
 335     prev->pc = FRAME_SAVED_PC (prev->next);
 336   else
 337     prev->pc = read_pc ();
 338 }
 339
 340 int
 341 cannot_register_not (int regnum)
 342 {
 343   return 0;
 344 }
 345
 346 /* Legacy version of target_virtual_frame_pointer().  Assumes that
 347    there is an FP_REGNUM and that it is the same, cooked or raw.  */
 348
 349 void
 350 legacy_virtual_frame_pointer (CORE_ADDR pc,
 351                               int *frame_regnum,
 352                               LONGEST *frame_offset)
 353 {
 354   gdb_assert (FP_REGNUM >= 0);
 355   *frame_regnum = FP_REGNUM;
 356   *frame_offset = 0;
 357 }
 358 \f
 359 /* Functions to manipulate the endianness of the target.  */
 360
 361 #ifdef TARGET_BYTE_ORDER_SELECTABLE
 362 /* compat - Catch old targets that expect a selectable byte-order to
 363    default to BIG_ENDIAN */
 364 #ifndef TARGET_BYTE_ORDER_DEFAULT
 365 #define TARGET_BYTE_ORDER_DEFAULT BIG_ENDIAN
 366 #endif
 367 #endif
 368 #if !TARGET_BYTE_ORDER_SELECTABLE_P
 369 #ifndef TARGET_BYTE_ORDER_DEFAULT
 370 /* compat - Catch old non byte-order selectable targets that do not
 371    define TARGET_BYTE_ORDER_DEFAULT and instead expect
 372    TARGET_BYTE_ORDER to be used as the default.  For targets that
 373    defined neither TARGET_BYTE_ORDER nor TARGET_BYTE_ORDER_DEFAULT the
 374    below will get a strange compiler warning. */
 375 #define TARGET_BYTE_ORDER_DEFAULT TARGET_BYTE_ORDER
 376 #endif
 377 #endif
 378 #ifndef TARGET_BYTE_ORDER_DEFAULT
 379 #define TARGET_BYTE_ORDER_DEFAULT BIG_ENDIAN /* arbitrary */
 380 #endif
 381 /* ``target_byte_order'' is only used when non- multi-arch.
 382    Multi-arch targets obtain the current byte order using
 383    TARGET_BYTE_ORDER which is controlled by gdbarch.*. */
 384 int target_byte_order = TARGET_BYTE_ORDER_DEFAULT;
 385 int target_byte_order_auto = 1;
 386
 387 static const char endian_big[] = "big";
 388 static const char endian_little[] = "little";
 389 static const char endian_auto[] = "auto";
 390 static const char *endian_enum[] =
 391 {
 392   endian_big,
 393   endian_little,
 394   endian_auto,
 395   NULL,
 396 };
 397 static const char *set_endian_string;
 398
 399 /* Called by ``show endian''.  */
 400
 401 static void
 402 show_endian (char *args, int from_tty)
 403 {
 404   if (TARGET_BYTE_ORDER_AUTO)
 405     printf_unfiltered ("The target endianness is set automatically (currently %s endian)\n",
 406                        (TARGET_BYTE_ORDER == BIG_ENDIAN ? "big" : "little"));
 407   else
 408     printf_unfiltered ("The target is assumed to be %s endian\n",
 409                        (TARGET_BYTE_ORDER == BIG_ENDIAN ? "big" : "little"));
 410 }
 411
 412 static void
 413 set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 414 {
 415   if (!TARGET_BYTE_ORDER_SELECTABLE_P)
 416     {
 417       printf_unfiltered ("Byte order is not selectable.");
 418     }
 419   else if (set_endian_string == endian_auto)
 420     {
 421       target_byte_order_auto = 1;
 422     }
 423   else if (set_endian_string == endian_little)
 424     {
 425       target_byte_order_auto = 0;
 426       if (GDB_MULTI_ARCH)
 427         {
 428           struct gdbarch_info info;
 429           memset (&info, 0, sizeof info);
 430           info.byte_order = LITTLE_ENDIAN;
 431           if (! gdbarch_update_p (info))
 432             {
 433               printf_unfiltered ("Little endian target not supported by GDB\n");
 434             }
 435         }
 436       else
 437         {
 438           target_byte_order = LITTLE_ENDIAN;
 439         }
 440     }
 441   else if (set_endian_string == endian_big)
 442     {
 443       target_byte_order_auto = 0;
 444       if (GDB_MULTI_ARCH)
 445         {
 446           struct gdbarch_info info;
 447           memset (&info, 0, sizeof info);
 448           info.byte_order = BIG_ENDIAN;
 449           if (! gdbarch_update_p (info))
 450             {
 451               printf_unfiltered ("Big endian target not supported by GDB\n");
 452             }
 453         }
 454       else
 455         {
 456           target_byte_order = BIG_ENDIAN;
 457         }
 458     }
 459   else
 460     internal_error (__FILE__, __LINE__,
 461                     "set_endian: bad value");
 462   show_endian (NULL, from_tty);
 463 }
 464
 465 /* Set the endianness from a BFD.  */
 466
 467 static void
 468 set_endian_from_file (bfd *abfd)
 469 {
 470   if (GDB_MULTI_ARCH)
 471     internal_error (__FILE__, __LINE__,
 472                     "set_endian_from_file: not for multi-arch");
 473   if (TARGET_BYTE_ORDER_SELECTABLE_P)
 474     {
 475       int want;
 476
 477       if (bfd_big_endian (abfd))
 478         want = BIG_ENDIAN;
 479       else
 480         want = LITTLE_ENDIAN;
 481       if (TARGET_BYTE_ORDER_AUTO)
 482         target_byte_order = want;
 483       else if (TARGET_BYTE_ORDER != want)
 484         warning ("%s endian file does not match %s endian target.",
 485                  want == BIG_ENDIAN ? "big" : "little",
 486                  TARGET_BYTE_ORDER == BIG_ENDIAN ? "big" : "little");
 487     }
 488   else
 489     {
 490       if (bfd_big_endian (abfd)
 491           ? TARGET_BYTE_ORDER != BIG_ENDIAN
 492           : TARGET_BYTE_ORDER == BIG_ENDIAN)
 493         warning ("%s endian file does not match %s endian target.",
 494                  bfd_big_endian (abfd) ? "big" : "little",
 495                  TARGET_BYTE_ORDER == BIG_ENDIAN ? "big" : "little");
 496     }
 497 }
 498
 499
 500 /* Functions to manipulate the architecture of the target */
 501
 502 enum set_arch { set_arch_auto, set_arch_manual };
 503
 504 int target_architecture_auto = 1;
 505
 506 const char *set_architecture_string;
 507
 508 /* Old way of changing the current architecture. */
 509
 510 extern const struct bfd_arch_info bfd_default_arch_struct;
 511 const struct bfd_arch_info *target_architecture = &bfd_default_arch_struct;
 512 int (*target_architecture_hook) (const struct bfd_arch_info *ap);
 513
 514 static int
 515 arch_ok (const struct bfd_arch_info *arch)
 516 {
 517   if (GDB_MULTI_ARCH)
 518     internal_error (__FILE__, __LINE__,
 519                     "arch_ok: not multi-arched");
 520   /* Should be performing the more basic check that the binary is
 521      compatible with GDB. */
 522   /* Check with the target that the architecture is valid. */
 523   return (target_architecture_hook == NULL
 524           || target_architecture_hook (arch));
 525 }
 526
 527 static void
 528 set_arch (const struct bfd_arch_info *arch,
 529           enum set_arch type)
 530 {
 531   if (GDB_MULTI_ARCH)
 532     internal_error (__FILE__, __LINE__,
 533                     "set_arch: not multi-arched");
 534   switch (type)
 535     {
 536     case set_arch_auto:
 537       if (!arch_ok (arch))
 538         warning ("Target may not support %s architecture",
 539                  arch->printable_name);
 540       target_architecture = arch;
 541       break;
 542     case set_arch_manual:
 543       if (!arch_ok (arch))
 544         {
 545           printf_unfiltered ("Target does not support `%s' architecture.\n",
 546                              arch->printable_name);
 547         }
 548       else
 549         {
 550           target_architecture_auto = 0;
 551           target_architecture = arch;
 552         }
 553       break;
 554     }
 555   if (gdbarch_debug)
 556     gdbarch_dump (current_gdbarch, gdb_stdlog);
 557 }
 558
 559 /* Set the architecture from arch/machine (deprecated) */
 560
 561 void
 562 set_architecture_from_arch_mach (enum bfd_architecture arch,
 563                                  unsigned long mach)
 564 {
 565   const struct bfd_arch_info *wanted = bfd_lookup_arch (arch, mach);
 566   if (GDB_MULTI_ARCH)
 567     internal_error (__FILE__, __LINE__,
 568                     "set_architecture_from_arch_mach: not multi-arched");
 569   if (wanted != NULL)
 570     set_arch (wanted, set_arch_manual);
 571   else
 572     internal_error (__FILE__, __LINE__,
 573                     "gdbarch: hardwired architecture/machine not recognized");
 574 }
 575
 576 /* Set the architecture from a BFD (deprecated) */
 577
 578 static void
 579 set_architecture_from_file (bfd *abfd)
 580 {
 581   const struct bfd_arch_info *wanted = bfd_get_arch_info (abfd);
 582   if (GDB_MULTI_ARCH)
 583     internal_error (__FILE__, __LINE__,
 584                     "set_architecture_from_file: not multi-arched");
 585   if (target_architecture_auto)
 586     {
 587       set_arch (wanted, set_arch_auto);
 588     }
 589   else if (wanted != target_architecture)
 590     {
 591       warning ("%s architecture file may be incompatible with %s target.",
 592                wanted->printable_name,
 593                target_architecture->printable_name);
 594     }
 595 }
 596
 597
 598 /* Called if the user enters ``show architecture'' without an
 599    argument. */
 600
 601 static void
 602 show_architecture (char *args, int from_tty)
 603 {
 604   const char *arch;
 605   arch = TARGET_ARCHITECTURE->printable_name;
 606   if (target_architecture_auto)
 607     printf_filtered ("The target architecture is set automatically (currently %s)\n", arch);
 608   else
 609     printf_filtered ("The target architecture is assumed to be %s\n", arch);
 610 }
 611
 612
 613 /* Called if the user enters ``set architecture'' with or without an
 614    argument. */
 615
 616 static void
 617 set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
 618 {
 619   if (strcmp (set_architecture_string, "auto") == 0)
 620     {
 621       target_architecture_auto = 1;
 622     }
 623   else if (GDB_MULTI_ARCH)
 624     {
 625       struct gdbarch_info info;
 626       memset (&info, 0, sizeof info);
 627       info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
 628       if (info.bfd_arch_info == NULL)
 629         internal_error (__FILE__, __LINE__,
 630                         "set_architecture: bfd_scan_arch failed");
 631       if (gdbarch_update_p (info))
 632         target_architecture_auto = 0;
 633       else
 634         printf_unfiltered ("Architecture `%s' not recognized.\n",
 635                            set_architecture_string);
 636     }
 637   else
 638     {
 639       const struct bfd_arch_info *arch
 640         = bfd_scan_arch (set_architecture_string);
 641       if (arch == NULL)
 642         internal_error (__FILE__, __LINE__,
 643                         "set_architecture: bfd_scan_arch failed");
 644       set_arch (arch, set_arch_manual);
 645     }
 646   show_architecture (NULL, from_tty);
 647 }
 648
 649 /* Set the dynamic target-system-dependent parameters (architecture,
 650    byte-order) using information found in the BFD */
 651
 652 void
 653 set_gdbarch_from_file (bfd *abfd)
 654 {
 655   if (GDB_MULTI_ARCH)
 656     {
 657       struct gdbarch_info info;
 658       memset (&info, 0, sizeof info);
 659       info.abfd = abfd;
 660       if (! gdbarch_update_p (info))
 661         error ("Architecture of file not recognized.\n");
 662     }
 663   else
 664     {
 665       set_architecture_from_file (abfd);
 666       set_endian_from_file (abfd);
 667     }
 668 }
 669
 670 /* Initialize the current architecture.  Update the ``set
 671    architecture'' command so that it specifies a list of valid
 672    architectures.  */
 673
 674 #ifdef DEFAULT_BFD_ARCH
 675 extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
 676 static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
 677 #else
 678 static const bfd_arch_info_type *default_bfd_arch;
 679 #endif
 680
 681 #ifdef DEFAULT_BFD_VEC
 682 extern const bfd_target DEFAULT_BFD_VEC;
 683 static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
 684 #else
 685 static const bfd_target *default_bfd_vec;
 686 #endif
 687
 688 void
 689 initialize_current_architecture (void)
 690 {
 691   const char **arches = gdbarch_printable_names ();
 692
 693   /* determine a default architecture and byte order. */
 694   struct gdbarch_info info;
 695   memset (&info, 0, sizeof (info));
 696
 697   /* Find a default architecture. */
 698   if (info.bfd_arch_info == NULL
 699       && default_bfd_arch != NULL)
 700     info.bfd_arch_info = default_bfd_arch;
 701   if (info.bfd_arch_info == NULL)
 702     {
 703       /* Choose the architecture by taking the first one
 704          alphabetically. */
 705       const char *chosen = arches[0];
 706       const char **arch;
 707       for (arch = arches; *arch != NULL; arch++)
 708         {
 709           if (strcmp (*arch, chosen) < 0)
 710             chosen = *arch;
 711         }
 712       if (chosen == NULL)
 713         internal_error (__FILE__, __LINE__,
 714                         "initialize_current_architecture: No arch");
 715       info.bfd_arch_info = bfd_scan_arch (chosen);
 716       if (info.bfd_arch_info == NULL)
 717         internal_error (__FILE__, __LINE__,
 718                         "initialize_current_architecture: Arch not found");
 719     }
 720
 721   /* take several guesses at a byte order. */
 722   /* NB: can't use TARGET_BYTE_ORDER_DEFAULT as its definition is
 723      forced above. */
 724   if (info.byte_order == 0
 725       && default_bfd_vec != NULL)
 726     {
 727       /* Extract BFD's default vector's byte order. */
 728       switch (default_bfd_vec->byteorder)
 729         {
 730         case BFD_ENDIAN_BIG:
 731           info.byte_order = BIG_ENDIAN;
 732           break;
 733         case BFD_ENDIAN_LITTLE:
 734           info.byte_order = LITTLE_ENDIAN;
 735           break;
 736         default:
 737           break;
 738         }
 739     }
 740   if (info.byte_order == 0)
 741     {
 742       /* look for ``*el-*'' in the target name. */
 743       const char *chp;
 744       chp = strchr (target_name, '-');
 745       if (chp != NULL
 746           && chp - 2 >= target_name
 747           && strncmp (chp - 2, "el", 2) == 0)
 748         info.byte_order = LITTLE_ENDIAN;
 749     }
 750   if (info.byte_order == 0)
 751     {
 752       /* Wire it to big-endian!!! */
 753       info.byte_order = BIG_ENDIAN;
 754     }
 755
 756   if (GDB_MULTI_ARCH)
 757     {
 758       if (! gdbarch_update_p (info))
 759         {
 760           internal_error (__FILE__, __LINE__,
 761                           "initialize_current_architecture: Selection of initial architecture failed");
 762         }
 763     }
 764   else
 765     initialize_non_multiarch ();
 766
 767   /* Create the ``set architecture'' command appending ``auto'' to the
 768      list of architectures. */
 769   {
 770     struct cmd_list_element *c;
 771     /* Append ``auto''. */
 772     int nr;
 773     for (nr = 0; arches[nr] != NULL; nr++);
 774     arches = xrealloc (arches, sizeof (char*) * (nr + 2));
 775     arches[nr + 0] = "auto";
 776     arches[nr + 1] = NULL;
 777     /* FIXME: add_set_enum_cmd() uses an array of ``char *'' instead
 778        of ``const char *''.  We just happen to know that the casts are
 779        safe. */
 780     c = add_set_enum_cmd ("architecture", class_support,
 781                           arches, &set_architecture_string,
 782                           "Set architecture of target.",
 783                           &setlist);
 784     c->function.sfunc = set_architecture;
 785     add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
 786     /* Don't use set_from_show - need to print both auto/manual and
 787        current setting. */
 788     add_cmd ("architecture", class_support, show_architecture,
 789              "Show the current target architecture", &showlist);
 790   }
 791 }
 792
 793
 794 /* */
 795
 796 extern initialize_file_ftype _initialize_gdbarch_utils;
 797
 798 void
 799 _initialize_gdbarch_utils (void)
 800 {
 801   struct cmd_list_element *c;
 802   c = add_set_enum_cmd ("endian", class_support,
 803                         endian_enum, &set_endian_string,
 804                         "Set endianness of target.",
 805                         &setlist);
 806   c->function.sfunc = set_endian;
 807   /* Don't use set_from_show - need to print both auto/manual and
 808      current setting. */
 809   add_cmd ("endian", class_support, show_endian,
 810            "Show the current byte-order", &showlist);
 811 }