gdb/arch-utils.c

   1 /* Dynamic architecture support for GDB, the GNU debugger.
   2
   3    Copyright 1998, 1999, 2000, 2001, 2002 Free Software Foundation,
   4    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., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24
  25 #if GDB_MULTI_ARCH
  26 #include "arch-utils.h"
  27 #include "gdbcmd.h"
  28 #include "inferior.h"           /* enum CALL_DUMMY_LOCATION et.al. */
  29 #else
  30 /* Just include everything in sight so that the every old definition
  31    of macro is visible. */
  32 #include "gdb_string.h"
  33 #include "symtab.h"
  34 #include "frame.h"
  35 #include "inferior.h"
  36 #include "breakpoint.h"
  37 #include "gdb_wait.h"
  38 #include "gdbcore.h"
  39 #include "gdbcmd.h"
  40 #include "target.h"
  41 #include "annotate.h"
  42 #endif
  43 #include "regcache.h"
  44 #include "gdb_assert.h"
  45
  46 #include "version.h"
  47
  48 #include "floatformat.h"
  49
  50 /* Use the program counter to determine the contents and size
  51    of a breakpoint instruction.  If no target-dependent macro
  52    BREAKPOINT_FROM_PC has been defined to implement this function,
  53    assume that the breakpoint doesn't depend on the PC, and
  54    use the values of the BIG_BREAKPOINT and LITTLE_BREAKPOINT macros.
  55    Return a pointer to a string of bytes that encode a breakpoint
  56    instruction, stores the length of the string to *lenptr,
  57    and optionally adjust the pc to point to the correct memory location
  58    for inserting the breakpoint.  */
  59
  60 const unsigned char *
  61 legacy_breakpoint_from_pc (CORE_ADDR * pcptr, int *lenptr)
  62 {
  63   /* {BIG_,LITTLE_}BREAKPOINT is the sequence of bytes we insert for a
  64      breakpoint.  On some machines, breakpoints are handled by the
  65      target environment and we don't have to worry about them here.  */
  66 #ifdef BIG_BREAKPOINT
  67   if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
  68     {
  69       static unsigned char big_break_insn[] = BIG_BREAKPOINT;
  70       *lenptr = sizeof (big_break_insn);
  71       return big_break_insn;
  72     }
  73 #endif
  74 #ifdef LITTLE_BREAKPOINT
  75   if (TARGET_BYTE_ORDER != BFD_ENDIAN_BIG)
  76     {
  77       static unsigned char little_break_insn[] = LITTLE_BREAKPOINT;
  78       *lenptr = sizeof (little_break_insn);
  79       return little_break_insn;
  80     }
  81 #endif
  82 #ifdef BREAKPOINT
  83   {
  84     static unsigned char break_insn[] = BREAKPOINT;
  85     *lenptr = sizeof (break_insn);
  86     return break_insn;
  87   }
  88 #endif
  89   *lenptr = 0;
  90   return NULL;
  91 }
  92
  93 int
  94 generic_frameless_function_invocation_not (struct frame_info *fi)
  95 {
  96   return 0;
  97 }
  98
  99 int
 100 generic_return_value_on_stack_not (struct type *type)
 101 {
 102   return 0;
 103 }
 104
 105 CORE_ADDR
 106 generic_skip_trampoline_code (CORE_ADDR pc)
 107 {
 108   return 0;
 109 }
 110
 111 int
 112 generic_in_solib_call_trampoline (CORE_ADDR pc, char *name)
 113 {
 114   return 0;
 115 }
 116
 117 int
 118 generic_in_function_epilogue_p (struct gdbarch *gdbarch, CORE_ADDR pc)
 119 {
 120   return 0;
 121 }
 122
 123 char *
 124 legacy_register_name (int i)
 125 {
 126 #ifdef REGISTER_NAMES
 127   static char *names[] = REGISTER_NAMES;
 128   if (i < 0 || i >= (sizeof (names) / sizeof (*names)))
 129     return NULL;
 130   else
 131     return names[i];
 132 #else
 133   internal_error (__FILE__, __LINE__,
 134                   "legacy_register_name: called.");
 135   return NULL;
 136 #endif
 137 }
 138
 139 #if defined (CALL_DUMMY)
 140 LONGEST legacy_call_dummy_words[] = CALL_DUMMY;
 141 #else
 142 LONGEST legacy_call_dummy_words[1];
 143 #endif
 144 int legacy_sizeof_call_dummy_words = sizeof (legacy_call_dummy_words);
 145
 146 void
 147 generic_remote_translate_xfer_address (CORE_ADDR gdb_addr, int gdb_len,
 148                                        CORE_ADDR * rem_addr, int *rem_len)
 149 {
 150   *rem_addr = gdb_addr;
 151   *rem_len = gdb_len;
 152 }
 153
 154 int
 155 generic_prologue_frameless_p (CORE_ADDR ip)
 156 {
 157   return ip == SKIP_PROLOGUE (ip);
 158 }
 159
 160 /* New/multi-arched targets should use the correct gdbarch field
 161    instead of using this global pointer. */
 162 int
 163 legacy_print_insn (bfd_vma vma, disassemble_info *info)
 164 {
 165   return (*tm_print_insn) (vma, info);
 166 }
 167
 168 /* Helper functions for INNER_THAN */
 169
 170 int
 171 core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
 172 {
 173   return (lhs < rhs);
 174 }
 175
 176 int
 177 core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
 178 {
 179   return (lhs > rhs);
 180 }
 181
 182
 183 /* Helper functions for TARGET_{FLOAT,DOUBLE}_FORMAT */
 184
 185 const struct floatformat *
 186 default_float_format (struct gdbarch *gdbarch)
 187 {
 188 #if GDB_MULTI_ARCH
 189   int byte_order = gdbarch_byte_order (gdbarch);
 190 #else
 191   int byte_order = TARGET_BYTE_ORDER;
 192 #endif
 193   switch (byte_order)
 194     {
 195     case BFD_ENDIAN_BIG:
 196       return &floatformat_ieee_single_big;
 197     case BFD_ENDIAN_LITTLE:
 198       return &floatformat_ieee_single_little;
 199     default:
 200       internal_error (__FILE__, __LINE__,
 201                       "default_float_format: bad byte order");
 202     }
 203 }
 204
 205
 206 const struct floatformat *
 207 default_double_format (struct gdbarch *gdbarch)
 208 {
 209 #if GDB_MULTI_ARCH
 210   int byte_order = gdbarch_byte_order (gdbarch);
 211 #else
 212   int byte_order = TARGET_BYTE_ORDER;
 213 #endif
 214   switch (byte_order)
 215     {
 216     case BFD_ENDIAN_BIG:
 217       return &floatformat_ieee_double_big;
 218     case BFD_ENDIAN_LITTLE:
 219       return &floatformat_ieee_double_little;
 220     default:
 221       internal_error (__FILE__, __LINE__,
 222                       "default_double_format: bad byte order");
 223     }
 224 }
 225
 226 void
 227 default_print_float_info (void)
 228 {
 229 #ifdef FLOAT_INFO
 230 #if GDB_MULTI_ARCH > GDB_MULTI_ARCH_PARTIAL
 231 #error "FLOAT_INFO defined in multi-arch"
 232 #endif
 233   FLOAT_INFO;
 234 #else
 235   printf_filtered ("No floating point info available for this processor.\n");
 236 #endif
 237 }
 238
 239 /* Misc helper functions for targets. */
 240
 241 int
 242 frame_num_args_unknown (struct frame_info *fi)
 243 {
 244   return -1;
 245 }
 246
 247
 248 int
 249 generic_register_convertible_not (int num)
 250 {
 251   return 0;
 252 }
 253
 254
 255 /* Under some ABI's that specify the `struct convention' for returning
 256    structures by value, by the time we've returned from the function,
 257    the return value is sitting there in the caller's buffer, but GDB
 258    has no way to find the address of that buffer.
 259
 260    On such architectures, use this function as your
 261    extract_struct_value_address method.  When asked to a struct
 262    returned by value in this fashion, GDB will print a nice error
 263    message, instead of garbage.  */
 264 CORE_ADDR
 265 generic_cannot_extract_struct_value_address (char *dummy)
 266 {
 267   return 0;
 268 }
 269
 270 int
 271 default_register_sim_regno (int num)
 272 {
 273   return num;
 274 }
 275
 276
 277 CORE_ADDR
 278 core_addr_identity (CORE_ADDR addr)
 279 {
 280   return addr;
 281 }
 282
 283 int
 284 no_op_reg_to_regnum (int reg)
 285 {
 286   return reg;
 287 }
 288
 289 /* For use by frame_args_address and frame_locals_address.  */
 290 CORE_ADDR
 291 default_frame_address (struct frame_info *fi)
 292 {
 293   return fi->frame;
 294 }
 295
 296 /* Default prepare_to_procced().  */
 297 int
 298 default_prepare_to_proceed (int select_it)
 299 {
 300   return 0;
 301 }
 302
 303 /* Generic prepare_to_proceed().  This one should be suitable for most
 304    targets that support threads. */
 305 int
 306 generic_prepare_to_proceed (int select_it)
 307 {
 308   ptid_t wait_ptid;
 309   struct target_waitstatus wait_status;
 310
 311   /* Get the last target status returned by target_wait().  */
 312   get_last_target_status (&wait_ptid, &wait_status);
 313
 314   /* Make sure we were stopped either at a breakpoint, or because
 315      of a Ctrl-C.  */
 316   if (wait_status.kind != TARGET_WAITKIND_STOPPED
 317       || (wait_status.value.sig != TARGET_SIGNAL_TRAP &&
 318           wait_status.value.sig != TARGET_SIGNAL_INT))
 319     {
 320       return 0;
 321     }
 322
 323   if (!ptid_equal (wait_ptid, minus_one_ptid)
 324       && !ptid_equal (inferior_ptid, wait_ptid))
 325     {
 326       /* Switched over from WAIT_PID.  */
 327       CORE_ADDR wait_pc = read_pc_pid (wait_ptid);
 328
 329       if (wait_pc != read_pc ())
 330         {
 331           if (select_it)
 332             {
 333               /* Switch back to WAIT_PID thread.  */
 334               inferior_ptid = wait_ptid;
 335
 336               /* FIXME: This stuff came from switch_to_thread() in
 337                  thread.c (which should probably be a public function).  */
 338               flush_cached_frames ();
 339               registers_changed ();
 340               stop_pc = wait_pc;
 341               select_frame (get_current_frame ());
 342             }
 343           /* We return 1 to indicate that there is a breakpoint here,
 344              so we need to step over it before continuing to avoid
 345              hitting it straight away. */
 346           if (breakpoint_here_p (wait_pc))
 347             {
 348               return 1;
 349             }
 350         }
 351     }
 352   return 0;
 353
 354 }
 355
 356 void
 357 init_frame_pc_noop (int fromleaf, struct frame_info *prev)
 358 {
 359   return;
 360 }
 361
 362 void
 363 init_frame_pc_default (int fromleaf, struct frame_info *prev)
 364 {
 365   if (fromleaf)
 366     prev->pc = SAVED_PC_AFTER_CALL (prev->next);
 367   else if (prev->next != NULL)
 368     prev->pc = FRAME_SAVED_PC (prev->next);
 369   else
 370     prev->pc = read_pc ();
 371 }
 372
 373 void
 374 default_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
 375 {
 376   return;
 377 }
 378
 379 void
 380 default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
 381 {
 382   return;
 383 }
 384
 385 int
 386 cannot_register_not (int regnum)
 387 {
 388   return 0;
 389 }
 390
 391 /* Legacy version of target_virtual_frame_pointer().  Assumes that
 392    there is an FP_REGNUM and that it is the same, cooked or raw.  */
 393
 394 void
 395 legacy_virtual_frame_pointer (CORE_ADDR pc,
 396                               int *frame_regnum,
 397                               LONGEST *frame_offset)
 398 {
 399   gdb_assert (FP_REGNUM >= 0);
 400   *frame_regnum = FP_REGNUM;
 401   *frame_offset = 0;
 402 }
 403
 404 /* Assume the world is sane, every register's virtual and real size
 405    is identical.  */
 406
 407 int
 408 generic_register_size (int regnum)
 409 {
 410   gdb_assert (regnum >= 0 && regnum < NUM_REGS + NUM_PSEUDO_REGS);
 411   return TYPE_LENGTH (REGISTER_VIRTUAL_TYPE (regnum));
 412 }
 413
 414 #if !defined (IN_SIGTRAMP)
 415 #if defined (SIGTRAMP_START)
 416 #define IN_SIGTRAMP(pc, name) \
 417        ((pc) >= SIGTRAMP_START(pc)   \
 418         && (pc) < SIGTRAMP_END(pc) \
 419         )
 420 #else
 421 #define IN_SIGTRAMP(pc, name) \
 422        (name && STREQ ("_sigtramp", name))
 423 #endif
 424 #endif
 425 \f
 426 int
 427 legacy_pc_in_sigtramp (CORE_ADDR pc, char *name)
 428 {
 429   return IN_SIGTRAMP(pc, name);
 430 }
 431
 432 \f
 433 /* Functions to manipulate the endianness of the target.  */
 434
 435 /* ``target_byte_order'' is only used when non- multi-arch.
 436    Multi-arch targets obtain the current byte order using the
 437    TARGET_BYTE_ORDER gdbarch method.
 438
 439    The choice of initial value is entirely arbitrary.  During startup,
 440    the function initialize_current_architecture() updates this value
 441    based on default byte-order information extracted from BFD.  */
 442 int target_byte_order = BFD_ENDIAN_BIG;
 443 int target_byte_order_auto = 1;
 444
 445 static const char endian_big[] = "big";
 446 static const char endian_little[] = "little";
 447 static const char endian_auto[] = "auto";
 448 static const char *endian_enum[] =
 449 {
 450   endian_big,
 451   endian_little,
 452   endian_auto,
 453   NULL,
 454 };
 455 static const char *set_endian_string;
 456
 457 /* Called by ``show endian''.  */
 458
 459 static void
 460 show_endian (char *args, int from_tty)
 461 {
 462   if (TARGET_BYTE_ORDER_AUTO)
 463     printf_unfiltered ("The target endianness is set automatically (currently %s endian)\n",
 464                        (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little"));
 465   else
 466     printf_unfiltered ("The target is assumed to be %s endian\n",
 467                        (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little"));
 468 }
 469
 470 static void
 471 set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 472 {
 473   if (set_endian_string == endian_auto)
 474     {
 475       target_byte_order_auto = 1;
 476     }
 477   else if (set_endian_string == endian_little)
 478     {
 479       target_byte_order_auto = 0;
 480       if (GDB_MULTI_ARCH)
 481         {
 482           struct gdbarch_info info;
 483           gdbarch_info_init (&info);
 484           info.byte_order = BFD_ENDIAN_LITTLE;
 485           if (! gdbarch_update_p (info))
 486             {
 487               printf_unfiltered ("Little endian target not supported by GDB\n");
 488             }
 489         }
 490       else
 491         {
 492           target_byte_order = BFD_ENDIAN_LITTLE;
 493         }
 494     }
 495   else if (set_endian_string == endian_big)
 496     {
 497       target_byte_order_auto = 0;
 498       if (GDB_MULTI_ARCH)
 499         {
 500           struct gdbarch_info info;
 501           gdbarch_info_init (&info);
 502           info.byte_order = BFD_ENDIAN_BIG;
 503           if (! gdbarch_update_p (info))
 504             {
 505               printf_unfiltered ("Big endian target not supported by GDB\n");
 506             }
 507         }
 508       else
 509         {
 510           target_byte_order = BFD_ENDIAN_BIG;
 511         }
 512     }
 513   else
 514     internal_error (__FILE__, __LINE__,
 515                     "set_endian: bad value");
 516   show_endian (NULL, from_tty);
 517 }
 518
 519 /* Set the endianness from a BFD.  */
 520
 521 static void
 522 set_endian_from_file (bfd *abfd)
 523 {
 524   int want;
 525   if (GDB_MULTI_ARCH)
 526     internal_error (__FILE__, __LINE__,
 527                     "set_endian_from_file: not for multi-arch");
 528   if (bfd_big_endian (abfd))
 529     want = BFD_ENDIAN_BIG;
 530   else
 531     want = BFD_ENDIAN_LITTLE;
 532   if (TARGET_BYTE_ORDER_AUTO)
 533     target_byte_order = want;
 534   else if (TARGET_BYTE_ORDER != want)
 535     warning ("%s endian file does not match %s endian target.",
 536              want == BFD_ENDIAN_BIG ? "big" : "little",
 537              TARGET_BYTE_ORDER == BFD_ENDIAN_BIG ? "big" : "little");
 538 }
 539
 540
 541 /* Functions to manipulate the architecture of the target */
 542
 543 enum set_arch { set_arch_auto, set_arch_manual };
 544
 545 int target_architecture_auto = 1;
 546
 547 const char *set_architecture_string;
 548
 549 /* Old way of changing the current architecture. */
 550
 551 extern const struct bfd_arch_info bfd_default_arch_struct;
 552 const struct bfd_arch_info *target_architecture = &bfd_default_arch_struct;
 553 int (*target_architecture_hook) (const struct bfd_arch_info *ap);
 554
 555 static int
 556 arch_ok (const struct bfd_arch_info *arch)
 557 {
 558   if (GDB_MULTI_ARCH)
 559     internal_error (__FILE__, __LINE__,
 560                     "arch_ok: not multi-arched");
 561   /* Should be performing the more basic check that the binary is
 562      compatible with GDB. */
 563   /* Check with the target that the architecture is valid. */
 564   return (target_architecture_hook == NULL
 565           || target_architecture_hook (arch));
 566 }
 567
 568 static void
 569 set_arch (const struct bfd_arch_info *arch,
 570           enum set_arch type)
 571 {
 572   if (GDB_MULTI_ARCH)
 573     internal_error (__FILE__, __LINE__,
 574                     "set_arch: not multi-arched");
 575   switch (type)
 576     {
 577     case set_arch_auto:
 578       if (!arch_ok (arch))
 579         warning ("Target may not support %s architecture",
 580                  arch->printable_name);
 581       target_architecture = arch;
 582       break;
 583     case set_arch_manual:
 584       if (!arch_ok (arch))
 585         {
 586           printf_unfiltered ("Target does not support `%s' architecture.\n",
 587                              arch->printable_name);
 588         }
 589       else
 590         {
 591           target_architecture_auto = 0;
 592           target_architecture = arch;
 593         }
 594       break;
 595     }
 596   if (gdbarch_debug)
 597     gdbarch_dump (current_gdbarch, gdb_stdlog);
 598 }
 599
 600 /* Set the architecture from arch/machine (deprecated) */
 601
 602 void
 603 set_architecture_from_arch_mach (enum bfd_architecture arch,
 604                                  unsigned long mach)
 605 {
 606   const struct bfd_arch_info *wanted = bfd_lookup_arch (arch, mach);
 607   if (GDB_MULTI_ARCH)
 608     internal_error (__FILE__, __LINE__,
 609                     "set_architecture_from_arch_mach: not multi-arched");
 610   if (wanted != NULL)
 611     set_arch (wanted, set_arch_manual);
 612   else
 613     internal_error (__FILE__, __LINE__,
 614                     "gdbarch: hardwired architecture/machine not recognized");
 615 }
 616
 617 /* Set the architecture from a BFD (deprecated) */
 618
 619 static void
 620 set_architecture_from_file (bfd *abfd)
 621 {
 622   const struct bfd_arch_info *wanted = bfd_get_arch_info (abfd);
 623   if (GDB_MULTI_ARCH)
 624     internal_error (__FILE__, __LINE__,
 625                     "set_architecture_from_file: not multi-arched");
 626   if (target_architecture_auto)
 627     {
 628       set_arch (wanted, set_arch_auto);
 629     }
 630   else if (wanted != target_architecture)
 631     {
 632       warning ("%s architecture file may be incompatible with %s target.",
 633                wanted->printable_name,
 634                target_architecture->printable_name);
 635     }
 636 }
 637
 638
 639 /* Called if the user enters ``show architecture'' without an
 640    argument. */
 641
 642 static void
 643 show_architecture (char *args, int from_tty)
 644 {
 645   const char *arch;
 646   arch = TARGET_ARCHITECTURE->printable_name;
 647   if (target_architecture_auto)
 648     printf_filtered ("The target architecture is set automatically (currently %s)\n", arch);
 649   else
 650     printf_filtered ("The target architecture is assumed to be %s\n", arch);
 651 }
 652
 653
 654 /* Called if the user enters ``set architecture'' with or without an
 655    argument. */
 656
 657 static void
 658 set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
 659 {
 660   if (strcmp (set_architecture_string, "auto") == 0)
 661     {
 662       target_architecture_auto = 1;
 663     }
 664   else if (GDB_MULTI_ARCH)
 665     {
 666       struct gdbarch_info info;
 667       gdbarch_info_init (&info);
 668       info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
 669       if (info.bfd_arch_info == NULL)
 670         internal_error (__FILE__, __LINE__,
 671                         "set_architecture: bfd_scan_arch failed");
 672       if (gdbarch_update_p (info))
 673         target_architecture_auto = 0;
 674       else
 675         printf_unfiltered ("Architecture `%s' not recognized.\n",
 676                            set_architecture_string);
 677     }
 678   else
 679     {
 680       const struct bfd_arch_info *arch
 681         = bfd_scan_arch (set_architecture_string);
 682       if (arch == NULL)
 683         internal_error (__FILE__, __LINE__,
 684                         "set_architecture: bfd_scan_arch failed");
 685       set_arch (arch, set_arch_manual);
 686     }
 687   show_architecture (NULL, from_tty);
 688 }
 689
 690 /* Set the dynamic target-system-dependent parameters (architecture,
 691    byte-order) using information found in the BFD */
 692
 693 void
 694 set_gdbarch_from_file (bfd *abfd)
 695 {
 696   if (GDB_MULTI_ARCH)
 697     {
 698       struct gdbarch_info info;
 699       gdbarch_info_init (&info);
 700       info.abfd = abfd;
 701       if (! gdbarch_update_p (info))
 702         error ("Architecture of file not recognized.\n");
 703     }
 704   else
 705     {
 706       set_architecture_from_file (abfd);
 707       set_endian_from_file (abfd);
 708     }
 709 }
 710
 711 /* Initialize the current architecture.  Update the ``set
 712    architecture'' command so that it specifies a list of valid
 713    architectures.  */
 714
 715 #ifdef DEFAULT_BFD_ARCH
 716 extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
 717 static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
 718 #else
 719 static const bfd_arch_info_type *default_bfd_arch;
 720 #endif
 721
 722 #ifdef DEFAULT_BFD_VEC
 723 extern const bfd_target DEFAULT_BFD_VEC;
 724 static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
 725 #else
 726 static const bfd_target *default_bfd_vec;
 727 #endif
 728
 729 void
 730 initialize_current_architecture (void)
 731 {
 732   const char **arches = gdbarch_printable_names ();
 733
 734   /* determine a default architecture and byte order. */
 735   struct gdbarch_info info;
 736   gdbarch_info_init (&info);
 737
 738   /* Find a default architecture. */
 739   if (info.bfd_arch_info == NULL
 740       && default_bfd_arch != NULL)
 741     info.bfd_arch_info = default_bfd_arch;
 742   if (info.bfd_arch_info == NULL)
 743     {
 744       /* Choose the architecture by taking the first one
 745          alphabetically. */
 746       const char *chosen = arches[0];
 747       const char **arch;
 748       for (arch = arches; *arch != NULL; arch++)
 749         {
 750           if (strcmp (*arch, chosen) < 0)
 751             chosen = *arch;
 752         }
 753       if (chosen == NULL)
 754         internal_error (__FILE__, __LINE__,
 755                         "initialize_current_architecture: No arch");
 756       info.bfd_arch_info = bfd_scan_arch (chosen);
 757       if (info.bfd_arch_info == NULL)
 758         internal_error (__FILE__, __LINE__,
 759                         "initialize_current_architecture: Arch not found");
 760     }
 761
 762   /* Take several guesses at a byte order.  */
 763   if (info.byte_order == BFD_ENDIAN_UNKNOWN
 764       && default_bfd_vec != NULL)
 765     {
 766       /* Extract BFD's default vector's byte order. */
 767       switch (default_bfd_vec->byteorder)
 768         {
 769         case BFD_ENDIAN_BIG:
 770           info.byte_order = BFD_ENDIAN_BIG;
 771           break;
 772         case BFD_ENDIAN_LITTLE:
 773           info.byte_order = BFD_ENDIAN_LITTLE;
 774           break;
 775         default:
 776           break;
 777         }
 778     }
 779   if (info.byte_order == BFD_ENDIAN_UNKNOWN)
 780     {
 781       /* look for ``*el-*'' in the target name. */
 782       const char *chp;
 783       chp = strchr (target_name, '-');
 784       if (chp != NULL
 785           && chp - 2 >= target_name
 786           && strncmp (chp - 2, "el", 2) == 0)
 787         info.byte_order = BFD_ENDIAN_LITTLE;
 788     }
 789   if (info.byte_order == BFD_ENDIAN_UNKNOWN)
 790     {
 791       /* Wire it to big-endian!!! */
 792       info.byte_order = BFD_ENDIAN_BIG;
 793     }
 794
 795   if (GDB_MULTI_ARCH)
 796     {
 797       if (! gdbarch_update_p (info))
 798         {
 799           internal_error (__FILE__, __LINE__,
 800                           "initialize_current_architecture: Selection of initial architecture failed");
 801         }
 802     }
 803   else
 804     {
 805       /* If the multi-arch logic comes up with a byte-order (from BFD)
 806          use it for the non-multi-arch case.  */
 807       if (info.byte_order != BFD_ENDIAN_UNKNOWN)
 808         target_byte_order = info.byte_order;
 809       initialize_non_multiarch ();
 810     }
 811
 812   /* Create the ``set architecture'' command appending ``auto'' to the
 813      list of architectures. */
 814   {
 815     struct cmd_list_element *c;
 816     /* Append ``auto''. */
 817     int nr;
 818     for (nr = 0; arches[nr] != NULL; nr++);
 819     arches = xrealloc (arches, sizeof (char*) * (nr + 2));
 820     arches[nr + 0] = "auto";
 821     arches[nr + 1] = NULL;
 822     /* FIXME: add_set_enum_cmd() uses an array of ``char *'' instead
 823        of ``const char *''.  We just happen to know that the casts are
 824        safe. */
 825     c = add_set_enum_cmd ("architecture", class_support,
 826                           arches, &set_architecture_string,
 827                           "Set architecture of target.",
 828                           &setlist);
 829     set_cmd_sfunc (c, set_architecture);
 830     add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
 831     /* Don't use set_from_show - need to print both auto/manual and
 832        current setting. */
 833     add_cmd ("architecture", class_support, show_architecture,
 834              "Show the current target architecture", &showlist);
 835   }
 836 }
 837
 838
 839 /* Initialize a gdbarch info to values that will be automatically
 840    overridden.  Note: Originally, this ``struct info'' was initialized
 841    using memset(0).  Unfortunatly, that ran into problems, namely
 842    BFD_ENDIAN_BIG is zero.  An explicit initialization function that
 843    can explicitly set each field to a well defined value is used.  */
 844
 845 void
 846 gdbarch_info_init (struct gdbarch_info *info)
 847 {
 848   memset (info, 0, sizeof (struct gdbarch_info));
 849   info->byte_order = BFD_ENDIAN_UNKNOWN;
 850 }
 851
 852 /* */
 853
 854 extern initialize_file_ftype _initialize_gdbarch_utils;
 855
 856 void
 857 _initialize_gdbarch_utils (void)
 858 {
 859   struct cmd_list_element *c;
 860   c = add_set_enum_cmd ("endian", class_support,
 861                         endian_enum, &set_endian_string,
 862                         "Set endianness of target.",
 863                         &setlist);
 864   set_cmd_sfunc (c, set_endian);
 865   /* Don't use set_from_show - need to print both auto/manual and
 866      current setting. */
 867   add_cmd ("endian", class_support, show_endian,
 868            "Show the current byte-order", &showlist);
 869 }