gas/config/obj-coff-seh.c

   1 /* seh pdata/xdata coff object file format
   2    Copyright (C) 2009-2019 Free Software Foundation, Inc.
   3
   4    This file is part of GAS.
   5
   6    GAS 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 3, or (at your option)
   9    any later version.
  10
  11    GAS 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 GAS; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20
  21 #include "obj-coff-seh.h"
  22
  23
  24 /* Private segment collection list.  */
  25 struct seh_seg_list {
  26   segT seg;
  27   int subseg;
  28   char *seg_name;
  29 };
  30
  31 /* Local data.  */
  32 static seh_context *seh_ctx_cur = NULL;
  33
  34 static struct hash_control *seh_hash;
  35
  36 static struct seh_seg_list *x_segcur = NULL;
  37 static struct seh_seg_list *p_segcur = NULL;
  38
  39 static void write_function_xdata (seh_context *);
  40 static void write_function_pdata (seh_context *);
  41
  42 \f
  43 /* Build based on segment the derived .pdata/.xdata
  44    segment name containing origin segment's postfix name part.  */
  45 static char *
  46 get_pxdata_name (segT seg, const char *base_name)
  47 {
  48   const char *name,*dollar, *dot;
  49   char *sname;
  50
  51   name = bfd_get_section_name (stdoutput, seg);
  52
  53   dollar = strchr (name, '$');
  54   dot = strchr (name + 1, '.');
  55
  56   if (!dollar && !dot)
  57     name = "";
  58   else if (!dollar)
  59     name = dot;
  60   else if (!dot)
  61     name = dollar;
  62   else if (dot < dollar)
  63     name = dot;
  64   else
  65     name = dollar;
  66
  67   sname = concat (base_name, name, NULL);
  68
  69   return sname;
  70 }
  71
  72 /* Allocate a seh_seg_list structure.  */
  73 static struct seh_seg_list *
  74 alloc_pxdata_item (segT seg, int subseg, char *name)
  75 {
  76   struct seh_seg_list *r;
  77
  78   r = (struct seh_seg_list *)
  79     xmalloc (sizeof (struct seh_seg_list) + strlen (name));
  80   r->seg = seg;
  81   r->subseg = subseg;
  82   r->seg_name = name;
  83   return r;
  84 }
  85
  86 /* Generate pdata/xdata segment with same linkonce properties
  87    of based segment.  */
  88 static segT
  89 make_pxdata_seg (segT cseg, char *name)
  90 {
  91   segT save_seg = now_seg;
  92   int save_subseg = now_subseg;
  93   segT r;
  94   flagword flags;
  95
  96   r = subseg_new (name, 0);
  97   /* Check if code segment is marked as linked once.  */
  98   flags = bfd_get_section_flags (stdoutput, cseg)
  99     & (SEC_LINK_ONCE | SEC_LINK_DUPLICATES_DISCARD
 100        | SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE
 101        | SEC_LINK_DUPLICATES_SAME_CONTENTS);
 102
 103   /* Add standard section flags.  */
 104   flags |= SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_DATA;
 105
 106   /* Apply possibly linked once flags to new generated segment, too.  */
 107   if (!bfd_set_section_flags (stdoutput, r, flags))
 108     as_bad (_("bfd_set_section_flags: %s"),
 109             bfd_errmsg (bfd_get_error ()));
 110
 111   /* Restore to previous segment.  */
 112   subseg_set (save_seg, save_subseg);
 113   return r;
 114 }
 115
 116 static void
 117 seh_hash_insert (const char *name, struct seh_seg_list *item)
 118 {
 119   const char *error_string;
 120
 121   if ((error_string = hash_jam (seh_hash, name, (char *) item)))
 122     as_fatal (_("Inserting \"%s\" into structure table failed: %s"),
 123               name, error_string);
 124 }
 125
 126 static struct seh_seg_list *
 127 seh_hash_find (char *name)
 128 {
 129   return (struct seh_seg_list *) hash_find (seh_hash, name);
 130 }
 131
 132 static struct seh_seg_list *
 133 seh_hash_find_or_make (segT cseg, const char *base_name)
 134 {
 135   struct seh_seg_list *item;
 136   char *name;
 137
 138   /* Initialize seh_hash once.  */
 139   if (!seh_hash)
 140     seh_hash = hash_new ();
 141
 142   name = get_pxdata_name (cseg, base_name);
 143
 144   item = seh_hash_find (name);
 145   if (!item)
 146     {
 147       item = alloc_pxdata_item (make_pxdata_seg (cseg, name), 0, name);
 148
 149       seh_hash_insert (item->seg_name, item);
 150     }
 151   else
 152     free (name);
 153
 154   return item;
 155 }
 156
 157 /* Check if current segment has same name.  */
 158 static int
 159 seh_validate_seg (const char *directive)
 160 {
 161   const char *cseg_name, *nseg_name;
 162   if (seh_ctx_cur->code_seg == now_seg)
 163     return 1;
 164   cseg_name = bfd_get_section_name (stdoutput, seh_ctx_cur->code_seg);
 165   nseg_name = bfd_get_section_name (stdoutput, now_seg);
 166   as_bad (_("%s used in segment '%s' instead of expected '%s'"),
 167           directive, nseg_name, cseg_name);
 168   ignore_rest_of_line ();
 169   return 0;
 170 }
 171
 172 /* Switch back to the code section, whatever that may be.  */
 173 static void
 174 obj_coff_seh_code (int ignored ATTRIBUTE_UNUSED)
 175 {
 176   subseg_set (seh_ctx_cur->code_seg, 0);
 177 }
 178
 179 static void
 180 switch_xdata (int subseg, segT code_seg)
 181 {
 182   x_segcur = seh_hash_find_or_make (code_seg, ".xdata");
 183
 184   subseg_set (x_segcur->seg, subseg);
 185 }
 186
 187 static void
 188 switch_pdata (segT code_seg)
 189 {
 190   p_segcur = seh_hash_find_or_make (code_seg, ".pdata");
 191
 192   subseg_set (p_segcur->seg, p_segcur->subseg);
 193 }
 194 \f
 195 /* Parsing routines.  */
 196
 197 /* Return the style of SEH unwind info to generate.  */
 198
 199 static seh_kind
 200 seh_get_target_kind (void)
 201 {
 202   if (!stdoutput)
 203     return seh_kind_unknown;
 204   switch (bfd_get_arch (stdoutput))
 205     {
 206     case bfd_arch_arm:
 207     case bfd_arch_powerpc:
 208     case bfd_arch_sh:
 209       return seh_kind_arm;
 210     case bfd_arch_i386:
 211       switch (bfd_get_mach (stdoutput))
 212         {
 213         case bfd_mach_x86_64:
 214         case bfd_mach_x86_64_intel_syntax:
 215           return seh_kind_x64;
 216         default:
 217           break;
 218         }
 219       /* FALL THROUGH.  */
 220     case bfd_arch_mips:
 221       return seh_kind_mips;
 222     case bfd_arch_ia64:
 223       /* Should return seh_kind_x64.  But not implemented yet.  */
 224       return seh_kind_unknown;
 225     default:
 226       break;
 227     }
 228   return seh_kind_unknown;
 229 }
 230
 231 /* Verify that we're in the context of a seh_proc.  */
 232
 233 static int
 234 verify_context (const char *directive)
 235 {
 236   if (seh_ctx_cur == NULL)
 237     {
 238       as_bad (_("%s used outside of .seh_proc block"), directive);
 239       ignore_rest_of_line ();
 240       return 0;
 241     }
 242   return 1;
 243 }
 244
 245 /* Similar, except we also verify the appropriate target.  */
 246
 247 static int
 248 verify_context_and_target (const char *directive, seh_kind target)
 249 {
 250   if (seh_get_target_kind () != target)
 251     {
 252       as_warn (_("%s ignored for this target"), directive);
 253       ignore_rest_of_line ();
 254       return 0;
 255     }
 256   return verify_context (directive);
 257 }
 258
 259 /* Skip whitespace and a comma.  Error if the comma is not seen.  */
 260
 261 static int
 262 skip_whitespace_and_comma (int required)
 263 {
 264   SKIP_WHITESPACE ();
 265   if (*input_line_pointer == ',')
 266     {
 267       input_line_pointer++;
 268       SKIP_WHITESPACE ();
 269       return 1;
 270     }
 271   else if (required)
 272     {
 273       as_bad (_("missing separator"));
 274       ignore_rest_of_line ();
 275     }
 276   else
 277     demand_empty_rest_of_line ();
 278   return 0;
 279 }
 280
 281 /* Mark current context to use 32-bit instruction (arm).  */
 282
 283 static void
 284 obj_coff_seh_32 (int what)
 285 {
 286   if (!verify_context_and_target ((what ? ".seh_32" : ".seh_no32"),
 287                                   seh_kind_arm))
 288     return;
 289
 290   seh_ctx_cur->use_instruction_32 = (what ? 1 : 0);
 291   demand_empty_rest_of_line ();
 292 }
 293
 294 /* Set for current context the handler and optional data (arm).  */
 295
 296 static void
 297 obj_coff_seh_eh (int what ATTRIBUTE_UNUSED)
 298 {
 299   if (!verify_context_and_target (".seh_eh", seh_kind_arm))
 300     return;
 301
 302   /* Write block to .text if exception handler is set.  */
 303   seh_ctx_cur->handler_written = 1;
 304   emit_expr (&seh_ctx_cur->handler, 4);
 305   emit_expr (&seh_ctx_cur->handler_data, 4);
 306
 307   demand_empty_rest_of_line ();
 308 }
 309
 310 /* Set for current context the default handler (x64).  */
 311
 312 static void
 313 obj_coff_seh_handler (int what ATTRIBUTE_UNUSED)
 314 {
 315   char *symbol_name;
 316   char name_end;
 317
 318   if (!verify_context (".seh_handler"))
 319     return;
 320
 321   if (*input_line_pointer == 0 || *input_line_pointer == '\n')
 322     {
 323       as_bad (_(".seh_handler requires a handler"));
 324       demand_empty_rest_of_line ();
 325       return;
 326     }
 327
 328   SKIP_WHITESPACE ();
 329
 330   if (*input_line_pointer == '@')
 331     {
 332       name_end = get_symbol_name (&symbol_name);
 333
 334       seh_ctx_cur->handler.X_op = O_constant;
 335       seh_ctx_cur->handler.X_add_number = 0;
 336
 337       if (strcasecmp (symbol_name, "@0") == 0
 338           || strcasecmp (symbol_name, "@null") == 0)
 339         ;
 340       else if (strcasecmp (symbol_name, "@1") == 0)
 341         seh_ctx_cur->handler.X_add_number = 1;
 342       else
 343         as_bad (_("unknown constant value '%s' for handler"), symbol_name);
 344
 345       (void) restore_line_pointer (name_end);
 346     }
 347   else
 348     expression (&seh_ctx_cur->handler);
 349
 350   seh_ctx_cur->handler_data.X_op = O_constant;
 351   seh_ctx_cur->handler_data.X_add_number = 0;
 352   seh_ctx_cur->handler_flags = 0;
 353
 354   if (!skip_whitespace_and_comma (0))
 355     return;
 356
 357   if (seh_get_target_kind () == seh_kind_x64)
 358     {
 359       do
 360         {
 361           name_end = get_symbol_name (&symbol_name);
 362
 363           if (strcasecmp (symbol_name, "@unwind") == 0)
 364             seh_ctx_cur->handler_flags |= UNW_FLAG_UHANDLER;
 365           else if (strcasecmp (symbol_name, "@except") == 0)
 366             seh_ctx_cur->handler_flags |= UNW_FLAG_EHANDLER;
 367           else
 368             as_bad (_(".seh_handler constant '%s' unknown"), symbol_name);
 369
 370           (void) restore_line_pointer (name_end);
 371         }
 372       while (skip_whitespace_and_comma (0));
 373     }
 374   else
 375     {
 376       expression (&seh_ctx_cur->handler_data);
 377       demand_empty_rest_of_line ();
 378
 379       if (seh_ctx_cur->handler_written)
 380         as_warn (_(".seh_handler after .seh_eh is ignored"));
 381     }
 382 }
 383
 384 /* Switch to subsection for handler data for exception region (x64).  */
 385
 386 static void
 387 obj_coff_seh_handlerdata (int what ATTRIBUTE_UNUSED)
 388 {
 389   if (!verify_context_and_target (".seh_handlerdata", seh_kind_x64))
 390     return;
 391   demand_empty_rest_of_line ();
 392
 393   switch_xdata (seh_ctx_cur->subsection + 1, seh_ctx_cur->code_seg);
 394 }
 395
 396 /* Mark end of current context.  */
 397
 398 static void
 399 do_seh_endproc (void)
 400 {
 401   seh_ctx_cur->end_addr = symbol_temp_new_now ();
 402
 403   write_function_xdata (seh_ctx_cur);
 404   write_function_pdata (seh_ctx_cur);
 405   seh_ctx_cur = NULL;
 406 }
 407
 408 static void
 409 obj_coff_seh_endproc (int what ATTRIBUTE_UNUSED)
 410 {
 411   demand_empty_rest_of_line ();
 412   if (seh_ctx_cur == NULL)
 413     {
 414       as_bad (_(".seh_endproc used without .seh_proc"));
 415       return;
 416     }
 417   seh_validate_seg (".seh_endproc");
 418   do_seh_endproc ();
 419 }
 420
 421 /* Mark begin of new context.  */
 422
 423 static void
 424 obj_coff_seh_proc (int what ATTRIBUTE_UNUSED)
 425 {
 426   char *symbol_name;
 427   char name_end;
 428
 429   if (seh_ctx_cur != NULL)
 430     {
 431       as_bad (_("previous SEH entry not closed (missing .seh_endproc)"));
 432       do_seh_endproc ();
 433     }
 434
 435   if (*input_line_pointer == 0 || *input_line_pointer == '\n')
 436     {
 437       as_bad (_(".seh_proc requires function label name"));
 438       demand_empty_rest_of_line ();
 439       return;
 440     }
 441
 442   seh_ctx_cur = XCNEW (seh_context);
 443
 444   seh_ctx_cur->code_seg = now_seg;
 445
 446   if (seh_get_target_kind () == seh_kind_x64)
 447     {
 448       x_segcur = seh_hash_find_or_make (seh_ctx_cur->code_seg, ".xdata");
 449       seh_ctx_cur->subsection = x_segcur->subseg;
 450       x_segcur->subseg += 2;
 451     }
 452
 453   SKIP_WHITESPACE ();
 454
 455   name_end = get_symbol_name (&symbol_name);
 456   seh_ctx_cur->func_name = xstrdup (symbol_name);
 457   (void) restore_line_pointer (name_end);
 458
 459   demand_empty_rest_of_line ();
 460
 461   seh_ctx_cur->start_addr = symbol_temp_new_now ();
 462 }
 463
 464 /* Mark end of prologue for current context.  */
 465
 466 static void
 467 obj_coff_seh_endprologue (int what ATTRIBUTE_UNUSED)
 468 {
 469   if (!verify_context (".seh_endprologue")
 470       || !seh_validate_seg (".seh_endprologue"))
 471     return;
 472   demand_empty_rest_of_line ();
 473
 474   if (seh_ctx_cur->endprologue_addr != NULL)
 475     as_warn (_("duplicate .seh_endprologue in .seh_proc block"));
 476   else
 477     seh_ctx_cur->endprologue_addr = symbol_temp_new_now ();
 478 }
 479
 480 /* End-of-file hook.  */
 481
 482 void
 483 obj_coff_seh_do_final (void)
 484 {
 485   if (seh_ctx_cur != NULL)
 486     as_bad (_("open SEH entry at end of file (missing .seh_endproc)"));
 487 }
 488
 489 /* Enter a prologue element into current context (x64).  */
 490
 491 static void
 492 seh_x64_make_prologue_element (int code, int info, offsetT off)
 493 {
 494   seh_prologue_element *n;
 495
 496   if (seh_ctx_cur == NULL)
 497     return;
 498   if (seh_ctx_cur->elems_count == seh_ctx_cur->elems_max)
 499     {
 500       seh_ctx_cur->elems_max += 8;
 501       seh_ctx_cur->elems = XRESIZEVEC (seh_prologue_element,
 502                                        seh_ctx_cur->elems,
 503                                        seh_ctx_cur->elems_max);
 504     }
 505
 506   n = &seh_ctx_cur->elems[seh_ctx_cur->elems_count++];
 507   n->code = code;
 508   n->info = info;
 509   n->off = off;
 510   n->pc_addr = symbol_temp_new_now ();
 511 }
 512
 513 /* Helper to read a register name from input stream (x64).  */
 514
 515 static int
 516 seh_x64_read_reg (const char *directive, int kind)
 517 {
 518   static const char * const int_regs[16] =
 519     { "rax", "rcx", "rdx", "rbx", "rsp", "rbp","rsi","rdi",
 520       "r8","r9","r10","r11","r12","r13","r14","r15" };
 521   static const char * const xmm_regs[16] =
 522     { "xmm0", "xmm1", "xmm2", "xmm3", "xmm4", "xmm5", "xmm6", "xmm7",
 523       "xmm8", "xmm9", "xmm10","xmm11","xmm12","xmm13","xmm14","xmm15" };
 524
 525   const char * const *regs = NULL;
 526   char name_end;
 527   char *symbol_name = NULL;
 528   int i;
 529
 530   switch (kind)
 531     {
 532     case 0:
 533     case 1:
 534       regs = int_regs;
 535       break;
 536     case 2:
 537       regs = xmm_regs;
 538       break;
 539     default:
 540       abort ();
 541     }
 542
 543   SKIP_WHITESPACE ();
 544   if (*input_line_pointer == '%')
 545     ++input_line_pointer;
 546   name_end = get_symbol_name (& symbol_name);
 547
 548   for (i = 0; i < 16; i++)
 549     if (! strcasecmp (regs[i], symbol_name))
 550       break;
 551
 552   (void) restore_line_pointer (name_end);
 553
 554   /* Error if register not found, or EAX used as a frame pointer.  */
 555   if (i == 16 || (kind == 0 && i == 0))
 556     {
 557       as_bad (_("invalid register for %s"), directive);
 558       return -1;
 559     }
 560
 561   return i;
 562 }
 563
 564 /* Add a register push-unwind token to the current context.  */
 565
 566 static void
 567 obj_coff_seh_pushreg (int what ATTRIBUTE_UNUSED)
 568 {
 569   int reg;
 570
 571   if (!verify_context_and_target (".seh_pushreg", seh_kind_x64)
 572       || !seh_validate_seg (".seh_pushreg"))
 573     return;
 574
 575   reg = seh_x64_read_reg (".seh_pushreg", 1);
 576   demand_empty_rest_of_line ();
 577
 578   if (reg < 0)
 579     return;
 580
 581   seh_x64_make_prologue_element (UWOP_PUSH_NONVOL, reg, 0);
 582 }
 583
 584 /* Add a register frame-unwind token to the current context.  */
 585
 586 static void
 587 obj_coff_seh_pushframe (int what ATTRIBUTE_UNUSED)
 588 {
 589   if (!verify_context_and_target (".seh_pushframe", seh_kind_x64)
 590       || !seh_validate_seg (".seh_pushframe"))
 591     return;
 592   demand_empty_rest_of_line ();
 593
 594   seh_x64_make_prologue_element (UWOP_PUSH_MACHFRAME, 0, 0);
 595 }
 596
 597 /* Add a register save-unwind token to current context.  */
 598
 599 static void
 600 obj_coff_seh_save (int what)
 601 {
 602   const char *directive = (what == 1 ? ".seh_savereg" : ".seh_savexmm");
 603   int code, reg, scale;
 604   offsetT off;
 605
 606   if (!verify_context_and_target (directive, seh_kind_x64)
 607       || !seh_validate_seg (directive))
 608     return;
 609
 610   reg = seh_x64_read_reg (directive, what);
 611
 612   if (!skip_whitespace_and_comma (1))
 613     return;
 614
 615   off = get_absolute_expression ();
 616   demand_empty_rest_of_line ();
 617
 618   if (reg < 0)
 619     return;
 620   if (off < 0)
 621     {
 622       as_bad (_("%s offset is negative"), directive);
 623       return;
 624     }
 625
 626   scale = (what == 1 ? 8 : 16);
 627
 628   if ((off & (scale - 1)) == 0 && off <= (offsetT) (0xffff * scale))
 629     {
 630       code = (what == 1 ? UWOP_SAVE_NONVOL : UWOP_SAVE_XMM128);
 631       off /= scale;
 632     }
 633   else if (off < (offsetT) 0xffffffff)
 634     code = (what == 1 ? UWOP_SAVE_NONVOL_FAR : UWOP_SAVE_XMM128_FAR);
 635   else
 636     {
 637       as_bad (_("%s offset out of range"), directive);
 638       return;
 639     }
 640
 641   seh_x64_make_prologue_element (code, reg, off);
 642 }
 643
 644 /* Add a stack-allocation token to current context.  */
 645
 646 static void
 647 obj_coff_seh_stackalloc (int what ATTRIBUTE_UNUSED)
 648 {
 649   offsetT off;
 650   int code, info;
 651
 652   if (!verify_context_and_target (".seh_stackalloc", seh_kind_x64)
 653       || !seh_validate_seg (".seh_stackalloc"))
 654     return;
 655
 656   off = get_absolute_expression ();
 657   demand_empty_rest_of_line ();
 658
 659   if (off == 0)
 660     return;
 661   if (off < 0)
 662     {
 663       as_bad (_(".seh_stackalloc offset is negative"));
 664       return;
 665     }
 666
 667   if ((off & 7) == 0 && off <= 128)
 668     code = UWOP_ALLOC_SMALL, info = (off - 8) >> 3, off = 0;
 669   else if ((off & 7) == 0 && off <= (offsetT) (0xffff * 8))
 670     code = UWOP_ALLOC_LARGE, info = 0, off >>= 3;
 671   else if (off <= (offsetT) 0xffffffff)
 672     code = UWOP_ALLOC_LARGE, info = 1;
 673   else
 674     {
 675       as_bad (_(".seh_stackalloc offset out of range"));
 676       return;
 677     }
 678
 679   seh_x64_make_prologue_element (code, info, off);
 680 }
 681
 682 /* Add a frame-pointer token to current context.  */
 683
 684 static void
 685 obj_coff_seh_setframe (int what ATTRIBUTE_UNUSED)
 686 {
 687   offsetT off;
 688   int reg;
 689
 690   if (!verify_context_and_target (".seh_setframe", seh_kind_x64)
 691       || !seh_validate_seg (".seh_setframe"))
 692     return;
 693
 694   reg = seh_x64_read_reg (".seh_setframe", 0);
 695
 696   if (!skip_whitespace_and_comma (1))
 697     return;
 698
 699   off = get_absolute_expression ();
 700   demand_empty_rest_of_line ();
 701
 702   if (reg < 0)
 703     return;
 704   if (off < 0)
 705     as_bad (_(".seh_setframe offset is negative"));
 706   else if (off > 240)
 707     as_bad (_(".seh_setframe offset out of range"));
 708   else if (off & 15)
 709     as_bad (_(".seh_setframe offset not a multiple of 16"));
 710   else if (seh_ctx_cur->framereg != 0)
 711     as_bad (_("duplicate .seh_setframe in current .seh_proc"));
 712   else
 713     {
 714       seh_ctx_cur->framereg = reg;
 715       seh_ctx_cur->frameoff = off;
 716       seh_x64_make_prologue_element (UWOP_SET_FPREG, 0, 0);
 717     }
 718 }
 719 \f
 720 /* Data writing routines.  */
 721
 722 /* Output raw integers in 1, 2, or 4 bytes.  */
 723
 724 static inline void
 725 out_one (int byte)
 726 {
 727   FRAG_APPEND_1_CHAR (byte);
 728 }
 729
 730 static inline void
 731 out_two (int data)
 732 {
 733   md_number_to_chars (frag_more (2), data, 2);
 734 }
 735
 736 static inline void
 737 out_four (int data)
 738 {
 739   md_number_to_chars (frag_more (4), data, 4);
 740 }
 741
 742 /* Write out prologue data for x64.  */
 743
 744 static void
 745 seh_x64_write_prologue_data (const seh_context *c)
 746 {
 747   int i;
 748
 749   /* We have to store in reverse order.  */
 750   for (i = c->elems_count - 1; i >= 0; --i)
 751     {
 752       const seh_prologue_element *e = c->elems + i;
 753       expressionS exp;
 754
 755       /* First comes byte offset in code.  */
 756       exp.X_op = O_subtract;
 757       exp.X_add_symbol = e->pc_addr;
 758       exp.X_op_symbol = c->start_addr;
 759       exp.X_add_number = 0;
 760       emit_expr (&exp, 1);
 761
 762       /* Second comes code+info packed into a byte.  */
 763       out_one ((e->info << 4) | e->code);
 764
 765       switch (e->code)
 766         {
 767         case UWOP_PUSH_NONVOL:
 768         case UWOP_ALLOC_SMALL:
 769         case UWOP_SET_FPREG:
 770         case UWOP_PUSH_MACHFRAME:
 771           /* These have no extra data.  */
 772           break;
 773
 774         case UWOP_ALLOC_LARGE:
 775           if (e->info)
 776             {
 777         case UWOP_SAVE_NONVOL_FAR:
 778         case UWOP_SAVE_XMM128_FAR:
 779               /* An unscaled 4 byte offset.  */
 780               out_four (e->off);
 781               break;
 782             }
 783           /* FALLTHRU */
 784
 785         case UWOP_SAVE_NONVOL:
 786         case UWOP_SAVE_XMM128:
 787           /* A scaled 2 byte offset.  */
 788           out_two (e->off);
 789           break;
 790
 791         default:
 792           abort ();
 793         }
 794     }
 795 }
 796
 797 static int
 798 seh_x64_size_prologue_data (const seh_context *c)
 799 {
 800   int i, ret = 0;
 801
 802   for (i = c->elems_count - 1; i >= 0; --i)
 803     switch (c->elems[i].code)
 804       {
 805       case UWOP_PUSH_NONVOL:
 806       case UWOP_ALLOC_SMALL:
 807       case UWOP_SET_FPREG:
 808       case UWOP_PUSH_MACHFRAME:
 809         ret += 1;
 810         break;
 811
 812       case UWOP_SAVE_NONVOL:
 813       case UWOP_SAVE_XMM128:
 814         ret += 2;
 815         break;
 816
 817       case UWOP_SAVE_NONVOL_FAR:
 818       case UWOP_SAVE_XMM128_FAR:
 819         ret += 3;
 820         break;
 821
 822       case UWOP_ALLOC_LARGE:
 823         ret += (c->elems[i].info ? 3 : 2);
 824         break;
 825
 826       default:
 827         abort ();
 828       }
 829
 830   return ret;
 831 }
 832
 833 /* Write out the xdata information for one function (x64).  */
 834
 835 static void
 836 seh_x64_write_function_xdata (seh_context *c)
 837 {
 838   int flags, count_unwind_codes;
 839   expressionS exp;
 840
 841   /* Set 4-byte alignment.  */
 842   frag_align (2, 0, 0);
 843
 844   c->xdata_addr = symbol_temp_new_now ();
 845   flags = c->handler_flags;
 846   count_unwind_codes = seh_x64_size_prologue_data (c);
 847
 848   /* ubyte:3 version, ubyte:5 flags.  */
 849   out_one ((flags << 3) | 1);
 850
 851   /* Size of prologue.  */
 852   if (c->endprologue_addr)
 853     {
 854       exp.X_op = O_subtract;
 855       exp.X_add_symbol = c->endprologue_addr;
 856       exp.X_op_symbol = c->start_addr;
 857       exp.X_add_number = 0;
 858       emit_expr (&exp, 1);
 859     }
 860   else
 861     out_one (0);
 862
 863   /* Number of slots (i.e. shorts) in the unwind codes array.  */
 864   if (count_unwind_codes > 255)
 865     as_fatal (_("too much unwind data in this .seh_proc"));
 866   out_one (count_unwind_codes);
 867
 868   /* ubyte:4 frame-reg, ubyte:4 frame-reg-offset.  */
 869   /* Note that frameoff is already a multiple of 16, and therefore
 870      the offset is already both scaled and shifted into place.  */
 871   out_one (c->frameoff | c->framereg);
 872
 873   seh_x64_write_prologue_data (c);
 874
 875   /* We need to align prologue data.  */
 876   if (count_unwind_codes & 1)
 877     out_two (0);
 878
 879   if (flags & (UNW_FLAG_EHANDLER | UNW_FLAG_UHANDLER))
 880     {
 881       /* Force the use of segment-relative relocations instead of absolute
 882          valued expressions.  Don't adjust for constants (e.g. NULL).  */
 883       if (c->handler.X_op == O_symbol)
 884         c->handler.X_op = O_symbol_rva;
 885       emit_expr (&c->handler, 4);
 886     }
 887
 888   /* Handler data will be tacked in here by subsections.  */
 889 }
 890
 891 /* Write out xdata for one function.  */
 892
 893 static void
 894 write_function_xdata (seh_context *c)
 895 {
 896   segT save_seg = now_seg;
 897   int save_subseg = now_subseg;
 898
 899   /* MIPS, SH, ARM don't have xdata.  */
 900   if (seh_get_target_kind () != seh_kind_x64)
 901     return;
 902
 903   switch_xdata (c->subsection, c->code_seg);
 904
 905   seh_x64_write_function_xdata (c);
 906
 907   subseg_set (save_seg, save_subseg);
 908 }
 909
 910 /* Write pdata section data for one function (arm).  */
 911
 912 static void
 913 seh_arm_write_function_pdata (seh_context *c)
 914 {
 915   expressionS exp;
 916   unsigned int prol_len = 0, func_len = 0;
 917   unsigned int val;
 918
 919   /* Start address of the function.  */
 920   exp.X_op = O_symbol;
 921   exp.X_add_symbol = c->start_addr;
 922   exp.X_add_number = 0;
 923   emit_expr (&exp, 4);
 924
 925   exp.X_op = O_subtract;
 926   exp.X_add_symbol = c->end_addr;
 927   exp.X_op_symbol = c->start_addr;
 928   exp.X_add_number = 0;
 929   if (resolve_expression (&exp) && exp.X_op == O_constant)
 930     func_len = exp.X_add_number;
 931   else
 932     as_bad (_(".seh_endproc in a different section from .seh_proc"));
 933
 934   if (c->endprologue_addr)
 935     {
 936       exp.X_op = O_subtract;
 937       exp.X_add_symbol = c->endprologue_addr;
 938       exp.X_op_symbol = c->start_addr;
 939       exp.X_add_number = 0;
 940
 941       if (resolve_expression (&exp) && exp.X_op == O_constant)
 942         prol_len = exp.X_add_number;
 943       else
 944         as_bad (_(".seh_endprologue in a different section from .seh_proc"));
 945     }
 946
 947   /* Both function and prologue are in units of instructions.  */
 948   func_len >>= (c->use_instruction_32 ? 2 : 1);
 949   prol_len >>= (c->use_instruction_32 ? 2 : 1);
 950
 951   /* Assemble the second word of the pdata.  */
 952   val  = prol_len & 0xff;
 953   val |= (func_len & 0x3fffff) << 8;
 954   if (c->use_instruction_32)
 955     val |= 0x40000000U;
 956   if (c->handler_written)
 957     val |= 0x80000000U;
 958   out_four (val);
 959 }
 960
 961 /* Write out pdata for one function.  */
 962
 963 static void
 964 write_function_pdata (seh_context *c)
 965 {
 966   expressionS exp;
 967   segT save_seg = now_seg;
 968   int save_subseg = now_subseg;
 969   memset (&exp, 0, sizeof (expressionS));
 970   switch_pdata (c->code_seg);
 971
 972   switch (seh_get_target_kind ())
 973     {
 974     case seh_kind_x64:
 975       exp.X_op = O_symbol_rva;
 976       exp.X_add_number = 0;
 977
 978       exp.X_add_symbol = c->start_addr;
 979       emit_expr (&exp, 4);
 980       exp.X_op = O_symbol_rva;
 981       exp.X_add_number = 0;
 982       exp.X_add_symbol = c->end_addr;
 983       emit_expr (&exp, 4);
 984       exp.X_op = O_symbol_rva;
 985       exp.X_add_number = 0;
 986       exp.X_add_symbol = c->xdata_addr;
 987       emit_expr (&exp, 4);
 988       break;
 989
 990     case seh_kind_mips:
 991       exp.X_op = O_symbol;
 992       exp.X_add_number = 0;
 993
 994       exp.X_add_symbol = c->start_addr;
 995       emit_expr (&exp, 4);
 996       exp.X_add_symbol = c->end_addr;
 997       emit_expr (&exp, 4);
 998
 999       emit_expr (&c->handler, 4);
1000       emit_expr (&c->handler_data, 4);
1001
1002       exp.X_add_symbol = (c->endprologue_addr
1003                           ? c->endprologue_addr
1004                           : c->start_addr);
1005       emit_expr (&exp, 4);
1006       break;
1007
1008     case seh_kind_arm:
1009       seh_arm_write_function_pdata (c);
1010       break;
1011
1012     default:
1013       abort ();
1014     }
1015
1016   subseg_set (save_seg, save_subseg);
1017 }