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
/* seh pdata/xdata coff object file format
   Copyright (C) 2009-2020 Free Software Foundation, Inc.

   This file is part of GAS.

   GAS 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, or (at your option)
   any later version.

   GAS 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 GAS; see the file COPYING.  If not, write to the Free
   Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
   02110-1301, USA.  */

#include "obj-coff-seh.h"


/* Private segment collection list.  */
struct seh_seg_list {
  segT seg;
  int subseg;
  char *seg_name;
};

/* Local data.  */
static seh_context *seh_ctx_cur = NULL;

static htab_t seh_hash;

static struct seh_seg_list *x_segcur = NULL;
static struct seh_seg_list *p_segcur = NULL;

static void write_function_xdata (seh_context *);
static void write_function_pdata (seh_context *);


/* Build based on segment the derived .pdata/.xdata
   segment name containing origin segment's postfix name part.  */
static char *
get_pxdata_name (segT seg, const char *base_name)
{
  const char *name,*dollar, *dot;
  char *sname;

  name = bfd_section_name (seg);

  dollar = strchr (name, '$');
  dot = strchr (name + 1, '.');

  if (!dollar && !dot)
    name = "";
  else if (!dollar)
    name = dot;
  else if (!dot)
    name = dollar;
  else if (dot < dollar)
    name = dot;
  else
    name = dollar;

  sname = concat (base_name, name, NULL);

  return sname;
}

/* Allocate a seh_seg_list structure.  */
static struct seh_seg_list *
alloc_pxdata_item (segT seg, int subseg, char *name)
{
  struct seh_seg_list *r;

  r = (struct seh_seg_list *)
    xmalloc (sizeof (struct seh_seg_list) + strlen (name));
  r->seg = seg;
  r->subseg = subseg;
  r->seg_name = name;
  return r;
}

/* Generate pdata/xdata segment with same linkonce properties
   of based segment.  */
static segT
make_pxdata_seg (segT cseg, char *name)
{
  segT save_seg = now_seg;
  int save_subseg = now_subseg;
  segT r;
  flagword flags;

  r = subseg_new (name, 0);
  /* Check if code segment is marked as linked once.  */
  flags = (bfd_section_flags (cseg)
	   & (SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
	      | SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE
	      | SEC_LINK_DUPLICATES_SAME_CONTENTS));

  /* Add standard section flags.  */
  flags |= SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_DATA;

  /* Apply possibly linked once flags to new generated segment, too.  */
  if (!bfd_set_section_flags (r, flags))
    as_bad (_("bfd_set_section_flags: %s"),
	    bfd_errmsg (bfd_get_error ()));

  /* Restore to previous segment.  */
  subseg_set (save_seg, save_subseg);
  return r;
}

static void
seh_hash_insert (const char *name, struct seh_seg_list *item)
{
  str_hash_insert (seh_hash, name, item, 1);
}

static struct seh_seg_list *
seh_hash_find (char *name)
{
  return (struct seh_seg_list *) str_hash_find (seh_hash, name);
}

static struct seh_seg_list *
seh_hash_find_or_make (segT cseg, const char *base_name)
{
  struct seh_seg_list *item;
  char *name;

  /* Initialize seh_hash once.  */
  if (!seh_hash)
    seh_hash = str_htab_create ();

  name = get_pxdata_name (cseg, base_name);

  item = seh_hash_find (name);
  if (!item)
    {
      item = alloc_pxdata_item (make_pxdata_seg (cseg, name), 0, name);

      seh_hash_insert (item->seg_name, item);
    }
  else
    free (name);

  return item;
}

/* Check if current segment has same name.  */
static int
seh_validate_seg (const char *directive)
{
  const char *cseg_name, *nseg_name;
  if (seh_ctx_cur->code_seg == now_seg)
    return 1;
  cseg_name = bfd_section_name (seh_ctx_cur->code_seg);
  nseg_name = bfd_section_name (now_seg);
  as_bad (_("%s used in segment '%s' instead of expected '%s'"),
  	  directive, nseg_name, cseg_name);
  ignore_rest_of_line ();
  return 0;
}

/* Switch back to the code section, whatever that may be.  */
static void
obj_coff_seh_code (int ignored ATTRIBUTE_UNUSED)
{
  subseg_set (seh_ctx_cur->code_seg, 0);
}

static void
switch_xdata (int subseg, segT code_seg)
{
  x_segcur = seh_hash_find_or_make (code_seg, ".xdata");

  subseg_set (x_segcur->seg, subseg);
}

static void
switch_pdata (segT code_seg)
{
  p_segcur = seh_hash_find_or_make (code_seg, ".pdata");

  subseg_set (p_segcur->seg, p_segcur->subseg);
}

/* Parsing routines.  */

/* Return the style of SEH unwind info to generate.  */

static seh_kind
seh_get_target_kind (void)
{
  if (!stdoutput)
    return seh_kind_unknown;
  switch (bfd_get_arch (stdoutput))
    {
    case bfd_arch_arm:
    case bfd_arch_powerpc:
    case bfd_arch_sh:
      return seh_kind_arm;
    case bfd_arch_i386:
      switch (bfd_get_mach (stdoutput))
	{
	case bfd_mach_x86_64:
	case bfd_mach_x86_64_intel_syntax:
	  return seh_kind_x64;
	default:
	  break;
	}
      /* FALL THROUGH.  */
    case bfd_arch_mips:
      return seh_kind_mips;
    case bfd_arch_ia64:
      /* Should return seh_kind_x64.  But not implemented yet.  */
      return seh_kind_unknown;
    default:
      break;
    }
  return seh_kind_unknown;
}

/* Verify that we're in the context of a seh_proc.  */

static int
verify_context (const char *directive)
{
  if (seh_ctx_cur == NULL)
    {
      as_bad (_("%s used outside of .seh_proc block"), directive);
      ignore_rest_of_line ();
      return 0;
    }
  return 1;
}

/* Similar, except we also verify the appropriate target.  */

static int
verify_context_and_target (const char *directive, seh_kind target)
{
  if (seh_get_target_kind () != target)
    {
      as_warn (_("%s ignored for this target"), directive);
      ignore_rest_of_line ();
      return 0;
    }
  return verify_context (directive);
}

/* Skip whitespace and a comma.  Error if the comma is not seen.  */

static int
skip_whitespace_and_comma (int required)
{
  SKIP_WHITESPACE ();
  if (*input_line_pointer == ',')
    {
      input_line_pointer++;
      SKIP_WHITESPACE ();
      return 1;
    }
  else if (required)
    {
      as_bad (_("missing separator"));
      ignore_rest_of_line ();
    }
  else
    demand_empty_rest_of_line ();
  return 0;
}

/* Mark current context to use 32-bit instruction (arm).  */

static void
obj_coff_seh_32 (int what)
{
  if (!verify_context_and_target ((what ? ".seh_32" : ".seh_no32"),
				  seh_kind_arm))
    return;

  seh_ctx_cur->use_instruction_32 = (what ? 1 : 0);
  demand_empty_rest_of_line ();
}

/* Set for current context the handler and optional data (arm).  */

static void
obj_coff_seh_eh (int what ATTRIBUTE_UNUSED)
{
  if (!verify_context_and_target (".seh_eh", seh_kind_arm))
    return;

  /* Write block to .text if exception handler is set.  */
  seh_ctx_cur->handler_written = 1;
  emit_expr (&seh_ctx_cur->handler, 4);
  emit_expr (&seh_ctx_cur->handler_data, 4);

  demand_empty_rest_of_line ();
}

/* Set for current context the default handler (x64).  */

static void
obj_coff_seh_handler (int what ATTRIBUTE_UNUSED)
{
  char *symbol_name;
  char name_end;

  if (!verify_context (".seh_handler"))
    return;

  if (*input_line_pointer == 0 || *input_line_pointer == '\n')
    {
      as_bad (_(".seh_handler requires a handler"));
      demand_empty_rest_of_line ();
      return;
    }

  SKIP_WHITESPACE ();

  if (*input_line_pointer == '@')
    {
      name_end = get_symbol_name (&symbol_name);

      seh_ctx_cur->handler.X_op = O_constant;
      seh_ctx_cur->handler.X_add_number = 0;

      if (strcasecmp (symbol_name, "@0") == 0
	  || strcasecmp (symbol_name, "@null") == 0)
	;
      else if (strcasecmp (symbol_name, "@1") == 0)
	seh_ctx_cur->handler.X_add_number = 1;
      else
	as_bad (_("unknown constant value '%s' for handler"), symbol_name);

      (void) restore_line_pointer (name_end);
    }
  else
    expression (&seh_ctx_cur->handler);

  seh_ctx_cur->handler_data.X_op = O_constant;
  seh_ctx_cur->handler_data.X_add_number = 0;
  seh_ctx_cur->handler_flags = 0;

  if (!skip_whitespace_and_comma (0))
    return;

  if (seh_get_target_kind () == seh_kind_x64)
    {
      do
	{
	  name_end = get_symbol_name (&symbol_name);

	  if (strcasecmp (symbol_name, "@unwind") == 0)
	    seh_ctx_cur->handler_flags |= UNW_FLAG_UHANDLER;
	  else if (strcasecmp (symbol_name, "@except") == 0)
	    seh_ctx_cur->handler_flags |= UNW_FLAG_EHANDLER;
	  else
	    as_bad (_(".seh_handler constant '%s' unknown"), symbol_name);

	  (void) restore_line_pointer (name_end);
	}
      while (skip_whitespace_and_comma (0));
    }
  else
    {
      expression (&seh_ctx_cur->handler_data);
      demand_empty_rest_of_line ();

      if (seh_ctx_cur->handler_written)
	as_warn (_(".seh_handler after .seh_eh is ignored"));
    }
}

/* Switch to subsection for handler data for exception region (x64).  */

static void
obj_coff_seh_handlerdata (int what ATTRIBUTE_UNUSED)
{
  if (!verify_context_and_target (".seh_handlerdata", seh_kind_x64))
    return;
  demand_empty_rest_of_line ();

  switch_xdata (seh_ctx_cur->subsection + 1, seh_ctx_cur->code_seg);
}

/* Mark end of current context.  */

static void
do_seh_endproc (void)
{
  seh_ctx_cur->end_addr = symbol_temp_new_now ();

  write_function_xdata (seh_ctx_cur);
  write_function_pdata (seh_ctx_cur);
  seh_ctx_cur = NULL;
}

static void
obj_coff_seh_endproc (int what ATTRIBUTE_UNUSED)
{
  demand_empty_rest_of_line ();
  if (seh_ctx_cur == NULL)
    {
      as_bad (_(".seh_endproc used without .seh_proc"));
      return;
    }
  seh_validate_seg (".seh_endproc");
  do_seh_endproc ();
}

/* Mark begin of new context.  */

static void
obj_coff_seh_proc (int what ATTRIBUTE_UNUSED)
{
  char *symbol_name;
  char name_end;

  if (seh_ctx_cur != NULL)
    {
      as_bad (_("previous SEH entry not closed (missing .seh_endproc)"));
      do_seh_endproc ();
    }

  if (*input_line_pointer == 0 || *input_line_pointer == '\n')
    {
      as_bad (_(".seh_proc requires function label name"));
      demand_empty_rest_of_line ();
      return;
    }

  seh_ctx_cur = XCNEW (seh_context);

  seh_ctx_cur->code_seg = now_seg;

  if (seh_get_target_kind () == seh_kind_x64)
    {
      x_segcur = seh_hash_find_or_make (seh_ctx_cur->code_seg, ".xdata");
      seh_ctx_cur->subsection = x_segcur->subseg;
      x_segcur->subseg += 2;
    }

  SKIP_WHITESPACE ();

  name_end = get_symbol_name (&symbol_name);
  seh_ctx_cur->func_name = xstrdup (symbol_name);
  (void) restore_line_pointer (name_end);

  demand_empty_rest_of_line ();

  seh_ctx_cur->start_addr = symbol_temp_new_now ();
}

/* Mark end of prologue for current context.  */

static void
obj_coff_seh_endprologue (int what ATTRIBUTE_UNUSED)
{
  if (!verify_context (".seh_endprologue")
      || !seh_validate_seg (".seh_endprologue"))
    return;
  demand_empty_rest_of_line ();

  if (seh_ctx_cur->endprologue_addr != NULL)
    as_warn (_("duplicate .seh_endprologue in .seh_proc block"));
  else
    seh_ctx_cur->endprologue_addr = symbol_temp_new_now ();
}

/* End-of-file hook.  */

void
obj_coff_seh_do_final (void)
{
  if (seh_ctx_cur != NULL)
    as_bad (_("open SEH entry at end of file (missing .seh_endproc)"));
}

/* Enter a prologue element into current context (x64).  */

static void
seh_x64_make_prologue_element (int code, int info, offsetT off)
{
  seh_prologue_element *n;

  if (seh_ctx_cur == NULL)
    return;
  if (seh_ctx_cur->elems_count == seh_ctx_cur->elems_max)
    {
      seh_ctx_cur->elems_max += 8;
      seh_ctx_cur->elems = XRESIZEVEC (seh_prologue_element,
				       seh_ctx_cur->elems,
				       seh_ctx_cur->elems_max);
    }

  n = &seh_ctx_cur->elems[seh_ctx_cur->elems_count++];
  n->code = code;
  n->info = info;
  n->off = off;
  n->pc_addr = symbol_temp_new_now ();
}

/* Helper to read a register name from input stream (x64).  */

static int
seh_x64_read_reg (const char *directive, int kind)
{
  static const char * const int_regs[16] =
    { "rax", "rcx", "rdx", "rbx", "rsp", "rbp","rsi","rdi",
      "r8","r9","r10","r11","r12","r13","r14","r15" };
  static const char * const xmm_regs[16] =
    { "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7",
      "xmm8", "xmm9", "xmm10","xmm11","xmm12","xmm13","xmm14","xmm15" };

  const char * const *regs = NULL;
  char name_end;
  char *symbol_name = NULL;
  int i;

  switch (kind)
    {
    case 0:
    case 1:
      regs = int_regs;
      break;
    case 2:
      regs = xmm_regs;
      break;
    default:
      abort ();
    }

  SKIP_WHITESPACE ();
  if (*input_line_pointer == '%')
    ++input_line_pointer;
  name_end = get_symbol_name (& symbol_name);

  for (i = 0; i < 16; i++)
    if (! strcasecmp (regs[i], symbol_name))
      break;

  (void) restore_line_pointer (name_end);

  /* Error if register not found, or EAX used as a frame pointer.  */
  if (i == 16 || (kind == 0 && i == 0))
    {
      as_bad (_("invalid register for %s"), directive);
      return -1;
    }

  return i;
}

/* Add a register push-unwind token to the current context.  */

static void
obj_coff_seh_pushreg (int what ATTRIBUTE_UNUSED)
{
  int reg;

  if (!verify_context_and_target (".seh_pushreg", seh_kind_x64)
      || !seh_validate_seg (".seh_pushreg"))
    return;

  reg = seh_x64_read_reg (".seh_pushreg", 1);
  demand_empty_rest_of_line ();

  if (reg < 0)
    return;

  seh_x64_make_prologue_element (UWOP_PUSH_NONVOL, reg, 0);
}

/* Add a register frame-unwind token to the current context.  */

static void
obj_coff_seh_pushframe (int what ATTRIBUTE_UNUSED)
{
  if (!verify_context_and_target (".seh_pushframe", seh_kind_x64)
      || !seh_validate_seg (".seh_pushframe"))
    return;
  demand_empty_rest_of_line ();

  seh_x64_make_prologue_element (UWOP_PUSH_MACHFRAME, 0, 0);
}

/* Add a register save-unwind token to current context.  */

static void
obj_coff_seh_save (int what)
{
  const char *directive = (what == 1 ? ".seh_savereg" : ".seh_savexmm");
  int code, reg, scale;
  offsetT off;

  if (!verify_context_and_target (directive, seh_kind_x64)
      || !seh_validate_seg (directive))
    return;

  reg = seh_x64_read_reg (directive, what);

  if (!skip_whitespace_and_comma (1))
    return;

  off = get_absolute_expression ();
  demand_empty_rest_of_line ();

  if (reg < 0)
    return;
  if (off < 0)
    {
      as_bad (_("%s offset is negative"), directive);
      return;
    }

  scale = (what == 1 ? 8 : 16);

  if ((off & (scale - 1)) == 0 && off <= (offsetT) (0xffff * scale))
    {
      code = (what == 1 ? UWOP_SAVE_NONVOL : UWOP_SAVE_XMM128);
      off /= scale;
    }
  else if (off < (offsetT) 0xffffffff)
    code = (what == 1 ? UWOP_SAVE_NONVOL_FAR : UWOP_SAVE_XMM128_FAR);
  else
    {
      as_bad (_("%s offset out of range"), directive);
      return;
    }

  seh_x64_make_prologue_element (code, reg, off);
}

/* Add a stack-allocation token to current context.  */

static void
obj_coff_seh_stackalloc (int what ATTRIBUTE_UNUSED)
{
  offsetT off;
  int code, info;

  if (!verify_context_and_target (".seh_stackalloc", seh_kind_x64)
      || !seh_validate_seg (".seh_stackalloc"))
    return;

  off = get_absolute_expression ();
  demand_empty_rest_of_line ();

  if (off == 0)
    return;
  if (off < 0)
    {
      as_bad (_(".seh_stackalloc offset is negative"));
      return;
    }

  if ((off & 7) == 0 && off <= 128)
    code = UWOP_ALLOC_SMALL, info = (off - 8) >> 3, off = 0;
  else if ((off & 7) == 0 && off <= (offsetT) (0xffff * 8))
    code = UWOP_ALLOC_LARGE, info = 0, off >>= 3;
  else if (off <= (offsetT) 0xffffffff)
    code = UWOP_ALLOC_LARGE, info = 1;
  else
    {
      as_bad (_(".seh_stackalloc offset out of range"));
      return;
    }

  seh_x64_make_prologue_element (code, info, off);
}

/* Add a frame-pointer token to current context.  */

static void
obj_coff_seh_setframe (int what ATTRIBUTE_UNUSED)
{
  offsetT off;
  int reg;

  if (!verify_context_and_target (".seh_setframe", seh_kind_x64)
      || !seh_validate_seg (".seh_setframe"))
    return;

  reg = seh_x64_read_reg (".seh_setframe", 0);

  if (!skip_whitespace_and_comma (1))
    return;

  off = get_absolute_expression ();
  demand_empty_rest_of_line ();

  if (reg < 0)
    return;
  if (off < 0)
    as_bad (_(".seh_setframe offset is negative"));
  else if (off > 240)
    as_bad (_(".seh_setframe offset out of range"));
  else if (off & 15)
    as_bad (_(".seh_setframe offset not a multiple of 16"));
  else if (seh_ctx_cur->framereg != 0)
    as_bad (_("duplicate .seh_setframe in current .seh_proc"));
  else
    {
      seh_ctx_cur->framereg = reg;
      seh_ctx_cur->frameoff = off;
      seh_x64_make_prologue_element (UWOP_SET_FPREG, 0, 0);
    }
}

/* Data writing routines.  */

/* Output raw integers in 1, 2, or 4 bytes.  */

static inline void
out_one (int byte)
{
  FRAG_APPEND_1_CHAR (byte);
}

static inline void
out_two (int data)
{
  md_number_to_chars (frag_more (2), data, 2);
}

static inline void
out_four (int data)
{
  md_number_to_chars (frag_more (4), data, 4);
}

/* Write out prologue data for x64.  */

static void
seh_x64_write_prologue_data (const seh_context *c)
{
  int i;

  /* We have to store in reverse order.  */
  for (i = c->elems_count - 1; i >= 0; --i)
    {
      const seh_prologue_element *e = c->elems + i;
      expressionS exp;

      /* First comes byte offset in code.  */
      exp.X_op = O_subtract;
      exp.X_add_symbol = e->pc_addr;
      exp.X_op_symbol = c->start_addr;
      exp.X_add_number = 0;
      emit_expr (&exp, 1);

      /* Second comes code+info packed into a byte.  */
      out_one ((e->info << 4) | e->code);

      switch (e->code)
	{
	case UWOP_PUSH_NONVOL:
	case UWOP_ALLOC_SMALL:
	case UWOP_SET_FPREG:
	case UWOP_PUSH_MACHFRAME:
	  /* These have no extra data.  */
	  break;

	case UWOP_ALLOC_LARGE:
	  if (e->info)
	    {
	case UWOP_SAVE_NONVOL_FAR:
	case UWOP_SAVE_XMM128_FAR:
	      /* An unscaled 4 byte offset.  */
	      out_four (e->off);
	      break;
	    }
	  /* FALLTHRU */

	case UWOP_SAVE_NONVOL:
	case UWOP_SAVE_XMM128:
	  /* A scaled 2 byte offset.  */
	  out_two (e->off);
	  break;

	default:
	  abort ();
	}
    }
}

static int
seh_x64_size_prologue_data (const seh_context *c)
{
  int i, ret = 0;

  for (i = c->elems_count - 1; i >= 0; --i)
    switch (c->elems[i].code)
      {
      case UWOP_PUSH_NONVOL:
      case UWOP_ALLOC_SMALL:
      case UWOP_SET_FPREG:
      case UWOP_PUSH_MACHFRAME:
	ret += 1;
	break;

      case UWOP_SAVE_NONVOL:
      case UWOP_SAVE_XMM128:
	ret += 2;
	break;

      case UWOP_SAVE_NONVOL_FAR:
      case UWOP_SAVE_XMM128_FAR:
	ret += 3;
	break;

      case UWOP_ALLOC_LARGE:
	ret += (c->elems[i].info ? 3 : 2);
	break;

      default:
	abort ();
      }

  return ret;
}

/* Write out the xdata information for one function (x64).  */

static void
seh_x64_write_function_xdata (seh_context *c)
{
  int flags, count_unwind_codes;
  expressionS exp;

  /* Set 4-byte alignment.  */
  frag_align (2, 0, 0);

  c->xdata_addr = symbol_temp_new_now ();
  flags = c->handler_flags;
  count_unwind_codes = seh_x64_size_prologue_data (c);

  /* ubyte:3 version, ubyte:5 flags.  */
  out_one ((flags << 3) | 1);

  /* Size of prologue.  */
  if (c->endprologue_addr)
    {
      exp.X_op = O_subtract;
      exp.X_add_symbol = c->endprologue_addr;
      exp.X_op_symbol = c->start_addr;
      exp.X_add_number = 0;
      emit_expr (&exp, 1);
    }
  else
    out_one (0);

  /* Number of slots (i.e. shorts) in the unwind codes array.  */
  if (count_unwind_codes > 255)
    as_fatal (_("too much unwind data in this .seh_proc"));
  out_one (count_unwind_codes);

  /* ubyte:4 frame-reg, ubyte:4 frame-reg-offset.  */
  /* Note that frameoff is already a multiple of 16, and therefore
     the offset is already both scaled and shifted into place.  */
  out_one (c->frameoff | c->framereg);

  seh_x64_write_prologue_data (c);

  /* We need to align prologue data.  */
  if (count_unwind_codes & 1)
    out_two (0);

  if (flags & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER))
    {
      /* Force the use of segment-relative relocations instead of absolute
         valued expressions.  Don't adjust for constants (e.g. NULL).  */
      if (c->handler.X_op == O_symbol)
        c->handler.X_op = O_symbol_rva;
      emit_expr (&c->handler, 4);
    }

  /* Handler data will be tacked in here by subsections.  */
}

/* Write out xdata for one function.  */

static void
write_function_xdata (seh_context *c)
{
  segT save_seg = now_seg;
  int save_subseg = now_subseg;

  /* MIPS, SH, ARM don't have xdata.  */
  if (seh_get_target_kind () != seh_kind_x64)
    return;

  switch_xdata (c->subsection, c->code_seg);

  seh_x64_write_function_xdata (c);

  subseg_set (save_seg, save_subseg);
}

/* Write pdata section data for one function (arm).  */

static void
seh_arm_write_function_pdata (seh_context *c)
{
  expressionS exp;
  unsigned int prol_len = 0, func_len = 0;
  unsigned int val;

  /* Start address of the function.  */
  exp.X_op = O_symbol;
  exp.X_add_symbol = c->start_addr;
  exp.X_add_number = 0;
  emit_expr (&exp, 4);

  exp.X_op = O_subtract;
  exp.X_add_symbol = c->end_addr;
  exp.X_op_symbol = c->start_addr;
  exp.X_add_number = 0;
  if (resolve_expression (&exp) && exp.X_op == O_constant)
    func_len = exp.X_add_number;
  else
    as_bad (_(".seh_endproc in a different section from .seh_proc"));

  if (c->endprologue_addr)
    {
      exp.X_op = O_subtract;
      exp.X_add_symbol = c->endprologue_addr;
      exp.X_op_symbol = c->start_addr;
      exp.X_add_number = 0;

      if (resolve_expression (&exp) && exp.X_op == O_constant)
	prol_len = exp.X_add_number;
      else
	as_bad (_(".seh_endprologue in a different section from .seh_proc"));
    }

  /* Both function and prologue are in units of instructions.  */
  func_len >>= (c->use_instruction_32 ? 2 : 1);
  prol_len >>= (c->use_instruction_32 ? 2 : 1);

  /* Assemble the second word of the pdata.  */
  val  = prol_len & 0xff;
  val |= (func_len & 0x3fffff) << 8;
  if (c->use_instruction_32)
    val |= 0x40000000U;
  if (c->handler_written)
    val |= 0x80000000U;
  out_four (val);
}

/* Write out pdata for one function.  */

static void
write_function_pdata (seh_context *c)
{
  expressionS exp;
  segT save_seg = now_seg;
  int save_subseg = now_subseg;
  memset (&exp, 0, sizeof (expressionS));
  switch_pdata (c->code_seg);

  switch (seh_get_target_kind ())
    {
    case seh_kind_x64:
      exp.X_op = O_symbol_rva;
      exp.X_add_number = 0;

      exp.X_add_symbol = c->start_addr;
      emit_expr (&exp, 4);
      exp.X_op = O_symbol_rva;
      exp.X_add_number = 0;
      exp.X_add_symbol = c->end_addr;
      emit_expr (&exp, 4);
      exp.X_op = O_symbol_rva;
      exp.X_add_number = 0;
      exp.X_add_symbol = c->xdata_addr;
      emit_expr (&exp, 4);
      break;

    case seh_kind_mips:
      exp.X_op = O_symbol;
      exp.X_add_number = 0;

      exp.X_add_symbol = c->start_addr;
      emit_expr (&exp, 4);
      exp.X_add_symbol = c->end_addr;
      emit_expr (&exp, 4);

      emit_expr (&c->handler, 4);
      emit_expr (&c->handler_data, 4);

      exp.X_add_symbol = (c->endprologue_addr
			  ? c->endprologue_addr
			  : c->start_addr);
      emit_expr (&exp, 4);
      break;

    case seh_kind_arm:
      seh_arm_write_function_pdata (c);
      break;

    default:
      abort ();
    }

  subseg_set (save_seg, save_subseg);
}