Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
/* Dynamic architecture support for GDB, the GNU debugger.

   Copyright (C) 1998-2020 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"

#include "arch-utils.h"
#include "gdbcmd.h"
#include "inferior.h"		/* enum CALL_DUMMY_LOCATION et al.  */
#include "infrun.h"
#include "regcache.h"
#include "sim-regno.h"
#include "gdbcore.h"
#include "osabi.h"
#include "target-descriptions.h"
#include "objfiles.h"
#include "language.h"
#include "symtab.h"

#include "gdbsupport/version.h"

#include "floatformat.h"

#include "dis-asm.h"

int
default_displaced_step_hw_singlestep (struct gdbarch *gdbarch,
				      struct displaced_step_closure *closure)
{
  return !gdbarch_software_single_step_p (gdbarch);
}

CORE_ADDR
displaced_step_at_entry_point (struct gdbarch *gdbarch)
{
  CORE_ADDR addr;
  int bp_len;

  addr = entry_point_address ();

  /* Inferior calls also use the entry point as a breakpoint location.
     We don't want displaced stepping to interfere with those
     breakpoints, so leave space.  */
  gdbarch_breakpoint_from_pc (gdbarch, &addr, &bp_len);
  addr += bp_len * 2;

  return addr;
}

int
legacy_register_sim_regno (struct gdbarch *gdbarch, int regnum)
{
  /* Only makes sense to supply raw registers.  */
  gdb_assert (regnum >= 0 && regnum < gdbarch_num_regs (gdbarch));
  /* NOTE: cagney/2002-05-13: The old code did it this way and it is
     suspected that some GDB/SIM combinations may rely on this
     behaviour.  The default should be one2one_register_sim_regno
     (below).  */
  if (gdbarch_register_name (gdbarch, regnum) != NULL
      && gdbarch_register_name (gdbarch, regnum)[0] != '\0')
    return regnum;
  else
    return LEGACY_SIM_REGNO_IGNORE;
}

CORE_ADDR
generic_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
{
  return 0;
}

CORE_ADDR
generic_skip_solib_resolver (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  return 0;
}

int
generic_in_solib_return_trampoline (struct gdbarch *gdbarch,
				    CORE_ADDR pc, const char *name)
{
  return 0;
}

int
generic_stack_frame_destroyed_p (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  return 0;
}

int
default_code_of_frame_writable (struct gdbarch *gdbarch,
				struct frame_info *frame)
{
  return 1;
}

/* Helper functions for gdbarch_inner_than */

int
core_addr_lessthan (CORE_ADDR lhs, CORE_ADDR rhs)
{
  return (lhs < rhs);
}

int
core_addr_greaterthan (CORE_ADDR lhs, CORE_ADDR rhs)
{
  return (lhs > rhs);
}

/* Misc helper functions for targets.  */

CORE_ADDR
core_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr)
{
  return addr;
}

CORE_ADDR
convert_from_func_ptr_addr_identity (struct gdbarch *gdbarch, CORE_ADDR addr,
				     struct target_ops *targ)
{
  return addr;
}

int
no_op_reg_to_regnum (struct gdbarch *gdbarch, int reg)
{
  return reg;
}

void
default_coff_make_msymbol_special (int val, struct minimal_symbol *msym)
{
  return;
}

/* See arch-utils.h.  */

void
default_make_symbol_special (struct symbol *sym, struct objfile *objfile)
{
  return;
}

/* See arch-utils.h.  */

CORE_ADDR
default_adjust_dwarf2_addr (CORE_ADDR pc)
{
  return pc;
}

/* See arch-utils.h.  */

CORE_ADDR
default_adjust_dwarf2_line (CORE_ADDR addr, int rel)
{
  return addr;
}

/* See arch-utils.h.  */

bool
default_execute_dwarf_cfa_vendor_op (struct gdbarch *gdbarch, gdb_byte op,
				     struct dwarf2_frame_state *fs)
{
  return false;
}

int
cannot_register_not (struct gdbarch *gdbarch, int regnum)
{
  return 0;
}

/* Legacy version of target_virtual_frame_pointer().  Assumes that
   there is an gdbarch_deprecated_fp_regnum and that it is the same,
   cooked or raw.  */

void
legacy_virtual_frame_pointer (struct gdbarch *gdbarch, 
			      CORE_ADDR pc,
			      int *frame_regnum,
			      LONGEST *frame_offset)
{
  /* FIXME: cagney/2002-09-13: This code is used when identifying the
     frame pointer of the current PC.  It is assuming that a single
     register and an offset can determine this.  I think it should
     instead generate a byte code expression as that would work better
     with things like Dwarf2's CFI.  */
  if (gdbarch_deprecated_fp_regnum (gdbarch) >= 0
      && gdbarch_deprecated_fp_regnum (gdbarch)
	   < gdbarch_num_regs (gdbarch))
    *frame_regnum = gdbarch_deprecated_fp_regnum (gdbarch);
  else if (gdbarch_sp_regnum (gdbarch) >= 0
	   && gdbarch_sp_regnum (gdbarch)
	        < gdbarch_num_regs (gdbarch))
    *frame_regnum = gdbarch_sp_regnum (gdbarch);
  else
    /* Should this be an internal error?  I guess so, it is reflecting
       an architectural limitation in the current design.  */
    internal_error (__FILE__, __LINE__, 
		    _("No virtual frame pointer available"));
  *frame_offset = 0;
}

/* Return a floating-point format for a floating-point variable of
   length LEN in bits.  If non-NULL, NAME is the name of its type.
   If no suitable type is found, return NULL.  */

const struct floatformat **
default_floatformat_for_type (struct gdbarch *gdbarch,
			      const char *name, int len)
{
  const struct floatformat **format = NULL;

  if (len == gdbarch_half_bit (gdbarch))
    format = gdbarch_half_format (gdbarch);
  else if (len == gdbarch_float_bit (gdbarch))
    format = gdbarch_float_format (gdbarch);
  else if (len == gdbarch_double_bit (gdbarch))
    format = gdbarch_double_format (gdbarch);
  else if (len == gdbarch_long_double_bit (gdbarch))
    format = gdbarch_long_double_format (gdbarch);
  /* On i386 the 'long double' type takes 96 bits,
     while the real number of used bits is only 80,
     both in processor and in memory.
     The code below accepts the real bit size.  */
  else if (gdbarch_long_double_format (gdbarch) != NULL
	   && len == gdbarch_long_double_format (gdbarch)[0]->totalsize)
    format = gdbarch_long_double_format (gdbarch);

  return format;
}

int
generic_convert_register_p (struct gdbarch *gdbarch, int regnum,
			    struct type *type)
{
  return 0;
}

int
default_stabs_argument_has_addr (struct gdbarch *gdbarch, struct type *type)
{
  return 0;
}

int
generic_instruction_nullified (struct gdbarch *gdbarch,
			       struct regcache *regcache)
{
  return 0;
}

int
default_remote_register_number (struct gdbarch *gdbarch,
				int regno)
{
  return regno;
}

/* See arch-utils.h.  */

int
default_vsyscall_range (struct gdbarch *gdbarch, struct mem_range *range)
{
  return 0;
}


/* Functions to manipulate the endianness of the target.  */

static enum bfd_endian target_byte_order_user = BFD_ENDIAN_UNKNOWN;

static const char endian_big[] = "big";
static const char endian_little[] = "little";
static const char endian_auto[] = "auto";
static const char *const endian_enum[] =
{
  endian_big,
  endian_little,
  endian_auto,
  NULL,
};
static const char *set_endian_string;

enum bfd_endian
selected_byte_order (void)
{
  return target_byte_order_user;
}

/* Called by ``show endian''.  */

static void
show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,
	     const char *value)
{
  if (target_byte_order_user == BFD_ENDIAN_UNKNOWN)
    if (gdbarch_byte_order (get_current_arch ()) == BFD_ENDIAN_BIG)
      fprintf_unfiltered (file, _("The target endianness is set automatically "
				  "(currently big endian).\n"));
    else
      fprintf_unfiltered (file, _("The target endianness is set automatically "
				  "(currently little endian).\n"));
  else
    if (target_byte_order_user == BFD_ENDIAN_BIG)
      fprintf_unfiltered (file,
			  _("The target is set to big endian.\n"));
    else
      fprintf_unfiltered (file,
			  _("The target is set to little endian.\n"));
}

static void
set_endian (const char *ignore_args, int from_tty, struct cmd_list_element *c)
{
  struct gdbarch_info info;

  gdbarch_info_init (&info);

  if (set_endian_string == endian_auto)
    {
      target_byte_order_user = BFD_ENDIAN_UNKNOWN;
      if (! gdbarch_update_p (info))
	internal_error (__FILE__, __LINE__,
			_("set_endian: architecture update failed"));
    }
  else if (set_endian_string == endian_little)
    {
      info.byte_order = BFD_ENDIAN_LITTLE;
      if (! gdbarch_update_p (info))
	printf_unfiltered (_("Little endian target not supported by GDB\n"));
      else
	target_byte_order_user = BFD_ENDIAN_LITTLE;
    }
  else if (set_endian_string == endian_big)
    {
      info.byte_order = BFD_ENDIAN_BIG;
      if (! gdbarch_update_p (info))
	printf_unfiltered (_("Big endian target not supported by GDB\n"));
      else
	target_byte_order_user = BFD_ENDIAN_BIG;
    }
  else
    internal_error (__FILE__, __LINE__,
		    _("set_endian: bad value"));

  show_endian (gdb_stdout, from_tty, NULL, NULL);
}

/* Given SELECTED, a currently selected BFD architecture, and
   TARGET_DESC, the current target description, return what
   architecture to use.

   SELECTED may be NULL, in which case we return the architecture
   associated with TARGET_DESC.  If SELECTED specifies a variant
   of the architecture associated with TARGET_DESC, return the
   more specific of the two.

   If SELECTED is a different architecture, but it is accepted as
   compatible by the target, we can use the target architecture.

   If SELECTED is obviously incompatible, warn the user.  */

static const struct bfd_arch_info *
choose_architecture_for_target (const struct target_desc *target_desc,
				const struct bfd_arch_info *selected)
{
  const struct bfd_arch_info *from_target = tdesc_architecture (target_desc);
  const struct bfd_arch_info *compat1, *compat2;

  if (selected == NULL)
    return from_target;

  if (from_target == NULL)
    return selected;

  /* struct bfd_arch_info objects are singletons: that is, there's
     supposed to be exactly one instance for a given machine.  So you
     can tell whether two are equivalent by comparing pointers.  */
  if (from_target == selected)
    return selected;

  /* BFD's 'A->compatible (A, B)' functions return zero if A and B are
     incompatible.  But if they are compatible, it returns the 'more
     featureful' of the two arches.  That is, if A can run code
     written for B, but B can't run code written for A, then it'll
     return A.

     Some targets (e.g. MIPS as of 2006-12-04) don't fully
     implement this, instead always returning NULL or the first
     argument.  We detect that case by checking both directions.  */

  compat1 = selected->compatible (selected, from_target);
  compat2 = from_target->compatible (from_target, selected);

  if (compat1 == NULL && compat2 == NULL)
    {
      /* BFD considers the architectures incompatible.  Check our
	 target description whether it accepts SELECTED as compatible
	 anyway.  */
      if (tdesc_compatible_p (target_desc, selected))
	return from_target;

      warning (_("Selected architecture %s is not compatible "
		 "with reported target architecture %s"),
	       selected->printable_name, from_target->printable_name);
      return selected;
    }

  if (compat1 == NULL)
    return compat2;
  if (compat2 == NULL)
    return compat1;
  if (compat1 == compat2)
    return compat1;

  /* If the two didn't match, but one of them was a default
     architecture, assume the more specific one is correct.  This
     handles the case where an executable or target description just
     says "mips", but the other knows which MIPS variant.  */
  if (compat1->the_default)
    return compat2;
  if (compat2->the_default)
    return compat1;

  /* We have no idea which one is better.  This is a bug, but not
     a critical problem; warn the user.  */
  warning (_("Selected architecture %s is ambiguous with "
	     "reported target architecture %s"),
	   selected->printable_name, from_target->printable_name);
  return selected;
}

/* Functions to manipulate the architecture of the target.  */

enum set_arch { set_arch_auto, set_arch_manual };

static const struct bfd_arch_info *target_architecture_user;

static const char *set_architecture_string;

const char *
selected_architecture_name (void)
{
  if (target_architecture_user == NULL)
    return NULL;
  else
    return set_architecture_string;
}

/* Called if the user enters ``show architecture'' without an
   argument.  */

static void
show_architecture (struct ui_file *file, int from_tty,
		   struct cmd_list_element *c, const char *value)
{
  if (target_architecture_user == NULL)
    fprintf_filtered (file, _("The target architecture is set to "
			      "\"auto\" (currently \"%s\").\n"),
		      gdbarch_bfd_arch_info (get_current_arch ())->printable_name);
  else
    fprintf_filtered (file, _("The target architecture is set to \"%s\".\n"),
		      set_architecture_string);
}


/* Called if the user enters ``set architecture'' with or without an
   argument.  */

static void
set_architecture (const char *ignore_args,
		  int from_tty, struct cmd_list_element *c)
{
  struct gdbarch_info info;

  gdbarch_info_init (&info);

  if (strcmp (set_architecture_string, "auto") == 0)
    {
      target_architecture_user = NULL;
      if (!gdbarch_update_p (info))
	internal_error (__FILE__, __LINE__,
			_("could not select an architecture automatically"));
    }
  else
    {
      info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
      if (info.bfd_arch_info == NULL)
	internal_error (__FILE__, __LINE__,
			_("set_architecture: bfd_scan_arch failed"));
      if (gdbarch_update_p (info))
	target_architecture_user = info.bfd_arch_info;
      else
	printf_unfiltered (_("Architecture `%s' not recognized.\n"),
			   set_architecture_string);
    }
  show_architecture (gdb_stdout, from_tty, NULL, NULL);
}

/* Try to select a global architecture that matches "info".  Return
   non-zero if the attempt succeeds.  */
int
gdbarch_update_p (struct gdbarch_info info)
{
  struct gdbarch *new_gdbarch;

  /* Check for the current file.  */
  if (info.abfd == NULL)
    info.abfd = exec_bfd;
  if (info.abfd == NULL)
    info.abfd = core_bfd;

  /* Check for the current target description.  */
  if (info.target_desc == NULL)
    info.target_desc = target_current_description ();

  new_gdbarch = gdbarch_find_by_info (info);

  /* If there no architecture by that name, reject the request.  */
  if (new_gdbarch == NULL)
    {
      if (gdbarch_debug)
	fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
			    "Architecture not found\n");
      return 0;
    }

  /* If it is the same old architecture, accept the request (but don't
     swap anything).  */
  if (new_gdbarch == target_gdbarch ())
    {
      if (gdbarch_debug)
	fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
			    "Architecture %s (%s) unchanged\n",
			    host_address_to_string (new_gdbarch),
			    gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
      return 1;
    }

  /* It's a new architecture, swap it in.  */
  if (gdbarch_debug)
    fprintf_unfiltered (gdb_stdlog, "gdbarch_update_p: "
			"New architecture %s (%s) selected\n",
			host_address_to_string (new_gdbarch),
			gdbarch_bfd_arch_info (new_gdbarch)->printable_name);
  set_target_gdbarch (new_gdbarch);

  return 1;
}

/* Return the architecture for ABFD.  If no suitable architecture
   could be find, return NULL.  */

struct gdbarch *
gdbarch_from_bfd (bfd *abfd)
{
  struct gdbarch_info info;
  gdbarch_info_init (&info);

  info.abfd = abfd;
  return gdbarch_find_by_info (info);
}

/* Set the dynamic target-system-dependent parameters (architecture,
   byte-order) using information found in the BFD */

void
set_gdbarch_from_file (bfd *abfd)
{
  struct gdbarch_info info;
  struct gdbarch *gdbarch;

  gdbarch_info_init (&info);
  info.abfd = abfd;
  info.target_desc = target_current_description ();
  gdbarch = gdbarch_find_by_info (info);

  if (gdbarch == NULL)
    error (_("Architecture of file not recognized."));
  set_target_gdbarch (gdbarch);
}

/* Initialize the current architecture.  Update the ``set
   architecture'' command so that it specifies a list of valid
   architectures.  */

#ifdef DEFAULT_BFD_ARCH
extern const bfd_arch_info_type DEFAULT_BFD_ARCH;
static const bfd_arch_info_type *default_bfd_arch = &DEFAULT_BFD_ARCH;
#else
static const bfd_arch_info_type *default_bfd_arch;
#endif

#ifdef DEFAULT_BFD_VEC
extern const bfd_target DEFAULT_BFD_VEC;
static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
#else
static const bfd_target *default_bfd_vec;
#endif

static enum bfd_endian default_byte_order = BFD_ENDIAN_UNKNOWN;

void
initialize_current_architecture (void)
{
  const char **arches = gdbarch_printable_names ();
  struct gdbarch_info info;

  /* determine a default architecture and byte order.  */
  gdbarch_info_init (&info);
  
  /* Find a default architecture.  */
  if (default_bfd_arch == NULL)
    {
      /* Choose the architecture by taking the first one
	 alphabetically.  */
      const char *chosen = arches[0];
      const char **arch;
      for (arch = arches; *arch != NULL; arch++)
	{
	  if (strcmp (*arch, chosen) < 0)
	    chosen = *arch;
	}
      if (chosen == NULL)
	internal_error (__FILE__, __LINE__,
			_("initialize_current_architecture: No arch"));
      default_bfd_arch = bfd_scan_arch (chosen);
      if (default_bfd_arch == NULL)
	internal_error (__FILE__, __LINE__,
			_("initialize_current_architecture: Arch not found"));
    }

  info.bfd_arch_info = default_bfd_arch;

  /* Take several guesses at a byte order.  */
  if (default_byte_order == BFD_ENDIAN_UNKNOWN
      && default_bfd_vec != NULL)
    {
      /* Extract BFD's default vector's byte order.  */
      switch (default_bfd_vec->byteorder)
	{
	case BFD_ENDIAN_BIG:
	  default_byte_order = BFD_ENDIAN_BIG;
	  break;
	case BFD_ENDIAN_LITTLE:
	  default_byte_order = BFD_ENDIAN_LITTLE;
	  break;
	default:
	  break;
	}
    }
  if (default_byte_order == BFD_ENDIAN_UNKNOWN)
    {
      /* look for ``*el-*'' in the target name.  */
      const char *chp;
      chp = strchr (target_name, '-');
      if (chp != NULL
	  && chp - 2 >= target_name
	  && startswith (chp - 2, "el"))
	default_byte_order = BFD_ENDIAN_LITTLE;
    }
  if (default_byte_order == BFD_ENDIAN_UNKNOWN)
    {
      /* Wire it to big-endian!!! */
      default_byte_order = BFD_ENDIAN_BIG;
    }

  info.byte_order = default_byte_order;
  info.byte_order_for_code = info.byte_order;

  if (! gdbarch_update_p (info))
    internal_error (__FILE__, __LINE__,
		    _("initialize_current_architecture: Selection of "
		      "initial architecture failed"));

  /* Create the ``set architecture'' command appending ``auto'' to the
     list of architectures.  */
  {
    /* Append ``auto''.  */
    int nr;
    for (nr = 0; arches[nr] != NULL; nr++);
    arches = XRESIZEVEC (const char *, arches, nr + 2);
    arches[nr + 0] = "auto";
    arches[nr + 1] = NULL;
    add_setshow_enum_cmd ("architecture", class_support,
			  arches, &set_architecture_string, 
			  _("Set architecture of target."),
			  _("Show architecture of target."), NULL,
			  set_architecture, show_architecture,
			  &setlist, &showlist);
    add_alias_cmd ("processor", "architecture", class_support, 1, &setlist);
  }
}


/* Initialize a gdbarch info to values that will be automatically
   overridden.  Note: Originally, this ``struct info'' was initialized
   using memset(0).  Unfortunately, that ran into problems, namely
   BFD_ENDIAN_BIG is zero.  An explicit initialization function that
   can explicitly set each field to a well defined value is used.  */

void
gdbarch_info_init (struct gdbarch_info *info)
{
  memset (info, 0, sizeof (struct gdbarch_info));
  info->byte_order = BFD_ENDIAN_UNKNOWN;
  info->byte_order_for_code = info->byte_order;
}

/* Similar to init, but this time fill in the blanks.  Information is
   obtained from the global "set ..." options and explicitly
   initialized INFO fields.  */

void
gdbarch_info_fill (struct gdbarch_info *info)
{
  /* "(gdb) set architecture ...".  */
  if (info->bfd_arch_info == NULL
      && target_architecture_user)
    info->bfd_arch_info = target_architecture_user;
  /* From the file.  */
  if (info->bfd_arch_info == NULL
      && info->abfd != NULL
      && bfd_get_arch (info->abfd) != bfd_arch_unknown
      && bfd_get_arch (info->abfd) != bfd_arch_obscure)
    info->bfd_arch_info = bfd_get_arch_info (info->abfd);
  /* From the target.  */
  if (info->target_desc != NULL)
    info->bfd_arch_info = choose_architecture_for_target
			   (info->target_desc, info->bfd_arch_info);
  /* From the default.  */
  if (info->bfd_arch_info == NULL)
    info->bfd_arch_info = default_bfd_arch;

  /* "(gdb) set byte-order ...".  */
  if (info->byte_order == BFD_ENDIAN_UNKNOWN
      && target_byte_order_user != BFD_ENDIAN_UNKNOWN)
    info->byte_order = target_byte_order_user;
  /* From the INFO struct.  */
  if (info->byte_order == BFD_ENDIAN_UNKNOWN
      && info->abfd != NULL)
    info->byte_order = (bfd_big_endian (info->abfd) ? BFD_ENDIAN_BIG
			: bfd_little_endian (info->abfd) ? BFD_ENDIAN_LITTLE
			: BFD_ENDIAN_UNKNOWN);
  /* From the default.  */
  if (info->byte_order == BFD_ENDIAN_UNKNOWN)
    info->byte_order = default_byte_order;
  info->byte_order_for_code = info->byte_order;
  /* Wire the default to the last selected byte order.  */
  default_byte_order = info->byte_order;

  /* "(gdb) set osabi ...".  Handled by gdbarch_lookup_osabi.  */
  /* From the manual override, or from file.  */
  if (info->osabi == GDB_OSABI_UNKNOWN)
    info->osabi = gdbarch_lookup_osabi (info->abfd);
  /* From the target.  */

  if (info->osabi == GDB_OSABI_UNKNOWN && info->target_desc != NULL)
    info->osabi = tdesc_osabi (info->target_desc);
  /* From the configured default.  */
#ifdef GDB_OSABI_DEFAULT
  if (info->osabi == GDB_OSABI_UNKNOWN)
    info->osabi = GDB_OSABI_DEFAULT;
#endif
  /* If we still don't know which osabi to pick, pick none.  */
  if (info->osabi == GDB_OSABI_UNKNOWN)
    info->osabi = GDB_OSABI_NONE;

  /* Must have at least filled in the architecture.  */
  gdb_assert (info->bfd_arch_info != NULL);
}

/* Return "current" architecture.  If the target is running, this is
   the architecture of the selected frame.  Otherwise, the "current"
   architecture defaults to the target architecture.

   This function should normally be called solely by the command
   interpreter routines to determine the architecture to execute a
   command in.  */
struct gdbarch *
get_current_arch (void)
{
  if (has_stack_frames ())
    return get_frame_arch (get_selected_frame (NULL));
  else
    return target_gdbarch ();
}

int
default_has_shared_address_space (struct gdbarch *gdbarch)
{
  /* Simply say no.  In most unix-like targets each inferior/process
     has its own address space.  */
  return 0;
}

int
default_fast_tracepoint_valid_at (struct gdbarch *gdbarch, CORE_ADDR addr,
				  std::string *msg)
{
  /* We don't know if maybe the target has some way to do fast
     tracepoints that doesn't need gdbarch, so always say yes.  */
  if (msg)
    msg->clear ();
  return 1;
}

const gdb_byte *
default_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr,
			    int *lenptr)
{
  int kind = gdbarch_breakpoint_kind_from_pc (gdbarch, pcptr);

  return gdbarch_sw_breakpoint_from_kind (gdbarch, kind, lenptr);
}
int
default_breakpoint_kind_from_current_state (struct gdbarch *gdbarch,
					    struct regcache *regcache,
					    CORE_ADDR *pcptr)
{
  return gdbarch_breakpoint_kind_from_pc (gdbarch, pcptr);
}


void
default_gen_return_address (struct gdbarch *gdbarch,
			    struct agent_expr *ax, struct axs_value *value,
			    CORE_ADDR scope)
{
  error (_("This architecture has no method to collect a return address."));
}

int
default_return_in_first_hidden_param_p (struct gdbarch *gdbarch,
					struct type *type)
{
  /* Usually, the return value's address is stored the in the "first hidden"
     parameter if the return value should be passed by reference, as
     specified in ABI.  */
  return !(language_pass_by_reference (type).trivially_copyable);
}

int default_insn_is_call (struct gdbarch *gdbarch, CORE_ADDR addr)
{
  return 0;
}

int default_insn_is_ret (struct gdbarch *gdbarch, CORE_ADDR addr)
{
  return 0;
}

int default_insn_is_jump (struct gdbarch *gdbarch, CORE_ADDR addr)
{
  return 0;
}

/*  See arch-utils.h.  */

bool
default_program_breakpoint_here_p (struct gdbarch *gdbarch,
				   CORE_ADDR address)
{
  int len;
  const gdb_byte *bpoint = gdbarch_breakpoint_from_pc (gdbarch, &address, &len);

  /* Software breakpoints unsupported?  */
  if (bpoint == nullptr)
    return false;

  gdb_byte *target_mem = (gdb_byte *) alloca (len);

  /* Enable the automatic memory restoration from breakpoints while
     we read the memory.  Otherwise we may find temporary breakpoints, ones
     inserted by GDB, and flag them as permanent breakpoints.  */
  scoped_restore restore_memory
    = make_scoped_restore_show_memory_breakpoints (0);

  if (target_read_memory (address, target_mem, len) == 0)
    {
      /* Check if this is a breakpoint instruction for this architecture,
	 including ones used by GDB.  */
      if (memcmp (target_mem, bpoint, len) == 0)
	return true;
    }

  return false;
}

void
default_skip_permanent_breakpoint (struct regcache *regcache)
{
  struct gdbarch *gdbarch = regcache->arch ();
  CORE_ADDR current_pc = regcache_read_pc (regcache);
  int bp_len;

  gdbarch_breakpoint_from_pc (gdbarch, &current_pc, &bp_len);
  current_pc += bp_len;
  regcache_write_pc (regcache, current_pc);
}

CORE_ADDR
default_infcall_mmap (CORE_ADDR size, unsigned prot)
{
  error (_("This target does not support inferior memory allocation by mmap."));
}

void
default_infcall_munmap (CORE_ADDR addr, CORE_ADDR size)
{
  /* Memory reserved by inferior mmap is kept leaked.  */
}

/* -mcmodel=large is used so that no GOT (Global Offset Table) is needed to be
   created in inferior memory by GDB (normally it is set by ld.so).  */

std::string
default_gcc_target_options (struct gdbarch *gdbarch)
{
  return string_printf ("-m%d%s", gdbarch_ptr_bit (gdbarch),
			(gdbarch_ptr_bit (gdbarch) == 64
			 ? " -mcmodel=large" : ""));
}

/* gdbarch gnu_triplet_regexp method.  */

const char *
default_gnu_triplet_regexp (struct gdbarch *gdbarch)
{
  return gdbarch_bfd_arch_info (gdbarch)->arch_name;
}

/* Default method for gdbarch_addressable_memory_unit_size.  By default, a memory byte has
   a size of 1 octet.  */

int
default_addressable_memory_unit_size (struct gdbarch *gdbarch)
{
  return 1;
}

void
default_guess_tracepoint_registers (struct gdbarch *gdbarch,
				    struct regcache *regcache,
				    CORE_ADDR addr)
{
  int pc_regno = gdbarch_pc_regnum (gdbarch);
  gdb_byte *regs;

  /* This guessing code below only works if the PC register isn't
     a pseudo-register.  The value of a pseudo-register isn't stored
     in the (non-readonly) regcache -- instead it's recomputed
     (probably from some other cached raw register) whenever the
     register is read.  In this case, a custom method implementation
     should be used by the architecture.  */
  if (pc_regno < 0 || pc_regno >= gdbarch_num_regs (gdbarch))
    return;

  regs = (gdb_byte *) alloca (register_size (gdbarch, pc_regno));
  store_unsigned_integer (regs, register_size (gdbarch, pc_regno),
			  gdbarch_byte_order (gdbarch), addr);
  regcache->raw_supply (pc_regno, regs);
}

int
default_print_insn (bfd_vma memaddr, disassemble_info *info)
{
  disassembler_ftype disassemble_fn;

  disassemble_fn = disassembler (info->arch, info->endian == BFD_ENDIAN_BIG,
				 info->mach, exec_bfd);

  gdb_assert (disassemble_fn != NULL);
  return (*disassemble_fn) (memaddr, info);
}

/* See arch-utils.h.  */

CORE_ADDR
gdbarch_skip_prologue_noexcept (gdbarch *gdbarch, CORE_ADDR pc) noexcept
{
  CORE_ADDR new_pc = pc;

  try
    {
      new_pc = gdbarch_skip_prologue (gdbarch, pc);
    }
  catch (const gdb_exception &ex)
    {}

  return new_pc;
}

/* See arch-utils.h.  */

bool
default_in_indirect_branch_thunk (gdbarch *gdbarch, CORE_ADDR pc)
{
  return false;
}

/* See arch-utils.h.  */

ULONGEST
default_type_align (struct gdbarch *gdbarch, struct type *type)
{
  return 0;
}

/* See arch-utils.h.  */

std::string
default_get_pc_address_flags (frame_info *frame, CORE_ADDR pc)
{
  return "";
}

/* See arch-utils.h.  */
void
default_read_core_file_mappings (struct gdbarch *gdbarch,
                                 struct bfd *cbfd,
				 gdb::function_view<void (ULONGEST count)>
				   pre_loop_cb,
				 gdb::function_view<void (int num,
				                          ULONGEST start,
							  ULONGEST end,
							  ULONGEST file_ofs,
							  const char *filename,
							  const void *other)>
				   loop_cb)
{
}

void _initialize_gdbarch_utils ();
void
_initialize_gdbarch_utils ()
{
  add_setshow_enum_cmd ("endian", class_support,
			endian_enum, &set_endian_string, 
			_("Set endianness of target."),
			_("Show endianness of target."),
			NULL, set_endian, show_endian,
			&setlist, &showlist);
}