gas/dw2gencfi.c

   1 /* dw2gencfi.c - Support for generating Dwarf2 CFI information.
   2    Copyright 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
   3    Contributed by Michal Ludvig <mludvig@suse.cz>
   4
   5    This file is part of GAS, the GNU Assembler.
   6
   7    GAS is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2, or (at your option)
  10    any later version.
  11
  12    GAS is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GAS; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #include "as.h"
  23 #include "dw2gencfi.h"
  24
  25
  26 /* We re-use DWARF2_LINE_MIN_INSN_LENGTH for the code alignment field
  27    of the CIE.  Default to 1 if not otherwise specified.  */
  28 #ifndef  DWARF2_LINE_MIN_INSN_LENGTH
  29 # define DWARF2_LINE_MIN_INSN_LENGTH 1
  30 #endif
  31
  32 /* If TARGET_USE_CFIPOP is defined, it is required that the target
  33    provide the following definitions.  Otherwise provide them to
  34    allow compilation to continue.  */
  35 #ifndef TARGET_USE_CFIPOP
  36 # ifndef  DWARF2_DEFAULT_RETURN_COLUMN
  37 #  define DWARF2_DEFAULT_RETURN_COLUMN 0
  38 # endif
  39 # ifndef  DWARF2_CIE_DATA_ALIGNMENT
  40 #  define DWARF2_CIE_DATA_ALIGNMENT 1
  41 # endif
  42 #endif
  43
  44 #ifndef EH_FRAME_ALIGNMENT
  45 # define EH_FRAME_ALIGNMENT (bfd_get_arch_size (stdoutput) == 64 ? 3 : 2)
  46 #endif
  47
  48 #ifndef tc_cfi_frame_initial_instructions
  49 # define tc_cfi_frame_initial_instructions() ((void)0)
  50 #endif
  51
  52
  53 struct cfi_insn_data
  54 {
  55   struct cfi_insn_data *next;
  56   int insn;
  57   union {
  58     struct {
  59       unsigned reg;
  60       offsetT offset;
  61     } ri;
  62
  63     struct {
  64       unsigned reg1;
  65       unsigned reg2;
  66     } rr;
  67
  68     unsigned r;
  69     offsetT i;
  70
  71     struct {
  72       symbolS *lab1;
  73       symbolS *lab2;
  74     } ll;
  75
  76     struct cfi_escape_data {
  77       struct cfi_escape_data *next;
  78       expressionS exp;
  79     } *esc;
  80   } u;
  81 };
  82
  83 struct fde_entry
  84 {
  85   struct fde_entry *next;
  86   symbolS *start_address;
  87   symbolS *end_address;
  88   struct cfi_insn_data *data;
  89   struct cfi_insn_data **last;
  90   unsigned int return_column;
  91   unsigned int signal_frame;
  92 };
  93
  94 struct cie_entry
  95 {
  96   struct cie_entry *next;
  97   symbolS *start_address;
  98   unsigned int return_column;
  99   unsigned int signal_frame;
 100   struct cfi_insn_data *first, *last;
 101 };
 102
 103
 104 /* Current open FDE entry.  */
 105 static struct fde_entry *cur_fde_data;
 106 static symbolS *last_address;
 107 static offsetT cur_cfa_offset;
 108
 109 /* List of FDE entries.  */
 110 static struct fde_entry *all_fde_data;
 111 static struct fde_entry **last_fde_data = &all_fde_data;
 112
 113 /* List of CIEs so that they could be reused.  */
 114 static struct cie_entry *cie_root;
 115
 116 /* Stack of old CFI data, for save/restore.  */
 117 struct cfa_save_data
 118 {
 119   struct cfa_save_data *next;
 120   offsetT cfa_offset;
 121 };
 122
 123 static struct cfa_save_data *cfa_save_stack;
 124 \f
 125 /* Construct a new FDE structure and add it to the end of the fde list.  */
 126
 127 static struct fde_entry *
 128 alloc_fde_entry (void)
 129 {
 130   struct fde_entry *fde = xcalloc (1, sizeof (struct fde_entry));
 131
 132   cur_fde_data = fde;
 133   *last_fde_data = fde;
 134   last_fde_data = &fde->next;
 135
 136   fde->last = &fde->data;
 137   fde->return_column = DWARF2_DEFAULT_RETURN_COLUMN;
 138
 139   return fde;
 140 }
 141
 142 /* The following functions are available for a backend to construct its
 143    own unwind information, usually from legacy unwind directives.  */
 144
 145 /* Construct a new INSN structure and add it to the end of the insn list
 146    for the currently active FDE.  */
 147
 148 static struct cfi_insn_data *
 149 alloc_cfi_insn_data (void)
 150 {
 151   struct cfi_insn_data *insn = xcalloc (1, sizeof (struct cfi_insn_data));
 152
 153   *cur_fde_data->last = insn;
 154   cur_fde_data->last = &insn->next;
 155
 156   return insn;
 157 }
 158
 159 /* Construct a new FDE structure that begins at LABEL.  */
 160
 161 void
 162 cfi_new_fde (symbolS *label)
 163 {
 164   struct fde_entry *fde = alloc_fde_entry ();
 165   fde->start_address = label;
 166   last_address = label;
 167 }
 168
 169 /* End the currently open FDE.  */
 170
 171 void
 172 cfi_end_fde (symbolS *label)
 173 {
 174   cur_fde_data->end_address = label;
 175   cur_fde_data = NULL;
 176 }
 177
 178 /* Set the return column for the current FDE.  */
 179
 180 void
 181 cfi_set_return_column (unsigned regno)
 182 {
 183   cur_fde_data->return_column = regno;
 184 }
 185
 186 /* Universal functions to store new instructions.  */
 187
 188 static void
 189 cfi_add_CFA_insn(int insn)
 190 {
 191   struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data ();
 192
 193   insn_ptr->insn = insn;
 194 }
 195
 196 static void
 197 cfi_add_CFA_insn_reg (int insn, unsigned regno)
 198 {
 199   struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data ();
 200
 201   insn_ptr->insn = insn;
 202   insn_ptr->u.r = regno;
 203 }
 204
 205 static void
 206 cfi_add_CFA_insn_offset (int insn, offsetT offset)
 207 {
 208   struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data ();
 209
 210   insn_ptr->insn = insn;
 211   insn_ptr->u.i = offset;
 212 }
 213
 214 static void
 215 cfi_add_CFA_insn_reg_reg (int insn, unsigned reg1, unsigned reg2)
 216 {
 217   struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data ();
 218
 219   insn_ptr->insn = insn;
 220   insn_ptr->u.rr.reg1 = reg1;
 221   insn_ptr->u.rr.reg2 = reg2;
 222 }
 223
 224 static void
 225 cfi_add_CFA_insn_reg_offset (int insn, unsigned regno, offsetT offset)
 226 {
 227   struct cfi_insn_data *insn_ptr = alloc_cfi_insn_data ();
 228
 229   insn_ptr->insn = insn;
 230   insn_ptr->u.ri.reg = regno;
 231   insn_ptr->u.ri.offset = offset;
 232 }
 233
 234 /* Add a CFI insn to advance the PC from the last address to LABEL.  */
 235
 236 void
 237 cfi_add_advance_loc (symbolS *label)
 238 {
 239   struct cfi_insn_data *insn = alloc_cfi_insn_data ();
 240
 241   insn->insn = DW_CFA_advance_loc;
 242   insn->u.ll.lab1 = last_address;
 243   insn->u.ll.lab2 = label;
 244
 245   last_address = label;
 246 }
 247
 248 /* Add a DW_CFA_offset record to the CFI data.  */
 249
 250 void
 251 cfi_add_CFA_offset (unsigned regno, offsetT offset)
 252 {
 253   unsigned int abs_data_align;
 254
 255   cfi_add_CFA_insn_reg_offset (DW_CFA_offset, regno, offset);
 256
 257   abs_data_align = (DWARF2_CIE_DATA_ALIGNMENT < 0
 258                     ? -DWARF2_CIE_DATA_ALIGNMENT : DWARF2_CIE_DATA_ALIGNMENT);
 259   if (offset % abs_data_align)
 260     as_bad (_("register save offset not a multiple of %u"), abs_data_align);
 261 }
 262
 263 /* Add a DW_CFA_def_cfa record to the CFI data.  */
 264
 265 void
 266 cfi_add_CFA_def_cfa (unsigned regno, offsetT offset)
 267 {
 268   cfi_add_CFA_insn_reg_offset (DW_CFA_def_cfa, regno, offset);
 269   cur_cfa_offset = offset;
 270 }
 271
 272 /* Add a DW_CFA_register record to the CFI data.  */
 273
 274 void
 275 cfi_add_CFA_register (unsigned reg1, unsigned reg2)
 276 {
 277   cfi_add_CFA_insn_reg_reg (DW_CFA_register, reg1, reg2);
 278 }
 279
 280 /* Add a DW_CFA_def_cfa_register record to the CFI data.  */
 281
 282 void
 283 cfi_add_CFA_def_cfa_register (unsigned regno)
 284 {
 285   cfi_add_CFA_insn_reg (DW_CFA_def_cfa_register, regno);
 286 }
 287
 288 /* Add a DW_CFA_def_cfa_offset record to the CFI data.  */
 289
 290 void
 291 cfi_add_CFA_def_cfa_offset (offsetT offset)
 292 {
 293   cfi_add_CFA_insn_offset (DW_CFA_def_cfa_offset, offset);
 294   cur_cfa_offset = offset;
 295 }
 296
 297 void
 298 cfi_add_CFA_restore (unsigned regno)
 299 {
 300   cfi_add_CFA_insn_reg (DW_CFA_restore, regno);
 301 }
 302
 303 void
 304 cfi_add_CFA_undefined (unsigned regno)
 305 {
 306   cfi_add_CFA_insn_reg (DW_CFA_undefined, regno);
 307 }
 308
 309 void
 310 cfi_add_CFA_same_value (unsigned regno)
 311 {
 312   cfi_add_CFA_insn_reg (DW_CFA_same_value, regno);
 313 }
 314
 315 void
 316 cfi_add_CFA_remember_state (void)
 317 {
 318   struct cfa_save_data *p;
 319
 320   cfi_add_CFA_insn (DW_CFA_remember_state);
 321
 322   p = xmalloc (sizeof (*p));
 323   p->cfa_offset = cur_cfa_offset;
 324   p->next = cfa_save_stack;
 325   cfa_save_stack = p;
 326 }
 327
 328 void
 329 cfi_add_CFA_restore_state (void)
 330 {
 331   struct cfa_save_data *p;
 332
 333   cfi_add_CFA_insn (DW_CFA_restore_state);
 334
 335   p = cfa_save_stack;
 336   if (p)
 337     {
 338       cur_cfa_offset = p->cfa_offset;
 339       cfa_save_stack = p->next;
 340       free (p);
 341     }
 342   else
 343     as_bad (_("CFI state restore without previous remember"));
 344 }
 345
 346 \f
 347 /* Parse CFI assembler directives.  */
 348
 349 static void dot_cfi (int);
 350 static void dot_cfi_escape (int);
 351 static void dot_cfi_startproc (int);
 352 static void dot_cfi_endproc (int);
 353
 354 /* Fake CFI type; outside the byte range of any real CFI insn.  */
 355 #define CFI_adjust_cfa_offset   0x100
 356 #define CFI_return_column       0x101
 357 #define CFI_rel_offset          0x102
 358 #define CFI_escape              0x103
 359 #define CFI_signal_frame        0x104
 360
 361 const pseudo_typeS cfi_pseudo_table[] =
 362   {
 363     { "cfi_startproc", dot_cfi_startproc, 0 },
 364     { "cfi_endproc", dot_cfi_endproc, 0 },
 365     { "cfi_def_cfa", dot_cfi, DW_CFA_def_cfa },
 366     { "cfi_def_cfa_register", dot_cfi, DW_CFA_def_cfa_register },
 367     { "cfi_def_cfa_offset", dot_cfi, DW_CFA_def_cfa_offset },
 368     { "cfi_adjust_cfa_offset", dot_cfi, CFI_adjust_cfa_offset },
 369     { "cfi_offset", dot_cfi, DW_CFA_offset },
 370     { "cfi_rel_offset", dot_cfi, CFI_rel_offset },
 371     { "cfi_register", dot_cfi, DW_CFA_register },
 372     { "cfi_return_column", dot_cfi, CFI_return_column },
 373     { "cfi_restore", dot_cfi, DW_CFA_restore },
 374     { "cfi_undefined", dot_cfi, DW_CFA_undefined },
 375     { "cfi_same_value", dot_cfi, DW_CFA_same_value },
 376     { "cfi_remember_state", dot_cfi, DW_CFA_remember_state },
 377     { "cfi_restore_state", dot_cfi, DW_CFA_restore_state },
 378     { "cfi_window_save", dot_cfi, DW_CFA_GNU_window_save },
 379     { "cfi_escape", dot_cfi_escape, 0 },
 380     { "cfi_signal_frame", dot_cfi, CFI_signal_frame },
 381     { NULL, NULL, 0 }
 382   };
 383
 384 static void
 385 cfi_parse_separator (void)
 386 {
 387   SKIP_WHITESPACE ();
 388   if (*input_line_pointer == ',')
 389     input_line_pointer++;
 390   else
 391     as_bad (_("missing separator"));
 392 }
 393
 394 static unsigned
 395 cfi_parse_reg (void)
 396 {
 397   int regno;
 398   expressionS exp;
 399
 400 #ifdef tc_regname_to_dw2regnum
 401   SKIP_WHITESPACE ();
 402   if (is_name_beginner (*input_line_pointer)
 403       || (*input_line_pointer == '%'
 404           && is_name_beginner (*++input_line_pointer)))
 405     {
 406       char *name, c;
 407
 408       name = input_line_pointer;
 409       c = get_symbol_end ();
 410
 411       if ((regno = tc_regname_to_dw2regnum (name)) < 0)
 412         {
 413           as_bad (_("bad register expression"));
 414           regno = 0;
 415         }
 416
 417       *input_line_pointer = c;
 418       return regno;
 419     }
 420 #endif
 421
 422   expression_and_evaluate (&exp);
 423   switch (exp.X_op)
 424     {
 425     case O_register:
 426     case O_constant:
 427       regno = exp.X_add_number;
 428       break;
 429
 430     default:
 431       as_bad (_("bad register expression"));
 432       regno = 0;
 433       break;
 434     }
 435
 436   return regno;
 437 }
 438
 439 static offsetT
 440 cfi_parse_const (void)
 441 {
 442   return get_absolute_expression ();
 443 }
 444
 445 static void
 446 dot_cfi (int arg)
 447 {
 448   offsetT offset;
 449   unsigned reg1, reg2;
 450
 451   if (!cur_fde_data)
 452     {
 453       as_bad (_("CFI instruction used without previous .cfi_startproc"));
 454       ignore_rest_of_line ();
 455       return;
 456     }
 457
 458   /* If the last address was not at the current PC, advance to current.  */
 459   if (symbol_get_frag (last_address) != frag_now
 460       || S_GET_VALUE (last_address) != frag_now_fix ())
 461     cfi_add_advance_loc (symbol_temp_new_now ());
 462
 463   switch (arg)
 464     {
 465     case DW_CFA_offset:
 466       reg1 = cfi_parse_reg ();
 467       cfi_parse_separator ();
 468       offset = cfi_parse_const ();
 469       cfi_add_CFA_offset (reg1, offset);
 470       break;
 471
 472     case CFI_rel_offset:
 473       reg1 = cfi_parse_reg ();
 474       cfi_parse_separator ();
 475       offset = cfi_parse_const ();
 476       cfi_add_CFA_offset (reg1, offset - cur_cfa_offset);
 477       break;
 478
 479     case DW_CFA_def_cfa:
 480       reg1 = cfi_parse_reg ();
 481       cfi_parse_separator ();
 482       offset = cfi_parse_const ();
 483       cfi_add_CFA_def_cfa (reg1, offset);
 484       break;
 485
 486     case DW_CFA_register:
 487       reg1 = cfi_parse_reg ();
 488       cfi_parse_separator ();
 489       reg2 = cfi_parse_reg ();
 490       cfi_add_CFA_register (reg1, reg2);
 491       break;
 492
 493     case DW_CFA_def_cfa_register:
 494       reg1 = cfi_parse_reg ();
 495       cfi_add_CFA_def_cfa_register (reg1);
 496       break;
 497
 498     case DW_CFA_def_cfa_offset:
 499       offset = cfi_parse_const ();
 500       cfi_add_CFA_def_cfa_offset (offset);
 501       break;
 502
 503     case CFI_adjust_cfa_offset:
 504       offset = cfi_parse_const ();
 505       cfi_add_CFA_def_cfa_offset (cur_cfa_offset + offset);
 506       break;
 507
 508     case DW_CFA_restore:
 509       for (;;)
 510         {
 511           reg1 = cfi_parse_reg ();
 512           cfi_add_CFA_restore (reg1);
 513           SKIP_WHITESPACE ();
 514           if (*input_line_pointer != ',')
 515             break;
 516           ++input_line_pointer;
 517         }
 518       break;
 519
 520     case DW_CFA_undefined:
 521       for (;;)
 522         {
 523           reg1 = cfi_parse_reg ();
 524           cfi_add_CFA_undefined (reg1);
 525           SKIP_WHITESPACE ();
 526           if (*input_line_pointer != ',')
 527             break;
 528           ++input_line_pointer;
 529         }
 530       break;
 531
 532     case DW_CFA_same_value:
 533       reg1 = cfi_parse_reg ();
 534       cfi_add_CFA_same_value (reg1);
 535       break;
 536
 537     case CFI_return_column:
 538       reg1 = cfi_parse_reg ();
 539       cfi_set_return_column (reg1);
 540       break;
 541
 542     case DW_CFA_remember_state:
 543       cfi_add_CFA_remember_state ();
 544       break;
 545
 546     case DW_CFA_restore_state:
 547       cfi_add_CFA_restore_state ();
 548       break;
 549
 550     case DW_CFA_GNU_window_save:
 551       cfi_add_CFA_insn (DW_CFA_GNU_window_save);
 552       break;
 553
 554     case CFI_signal_frame:
 555       cur_fde_data->signal_frame = 1;
 556       break;
 557
 558     default:
 559       abort ();
 560     }
 561
 562   demand_empty_rest_of_line ();
 563 }
 564
 565 static void
 566 dot_cfi_escape (int ignored ATTRIBUTE_UNUSED)
 567 {
 568   struct cfi_escape_data *head, **tail, *e;
 569   struct cfi_insn_data *insn;
 570
 571   if (!cur_fde_data)
 572     {
 573       as_bad (_("CFI instruction used without previous .cfi_startproc"));
 574       ignore_rest_of_line ();
 575       return;
 576     }
 577
 578   /* If the last address was not at the current PC, advance to current.  */
 579   if (symbol_get_frag (last_address) != frag_now
 580       || S_GET_VALUE (last_address) != frag_now_fix ())
 581     cfi_add_advance_loc (symbol_temp_new_now ());
 582
 583   tail = &head;
 584   do
 585     {
 586       e = xmalloc (sizeof (*e));
 587       do_parse_cons_expression (&e->exp, 1);
 588       *tail = e;
 589       tail = &e->next;
 590     }
 591   while (*input_line_pointer++ == ',');
 592   *tail = NULL;
 593
 594   insn = alloc_cfi_insn_data ();
 595   insn->insn = CFI_escape;
 596   insn->u.esc = head;
 597
 598   --input_line_pointer;
 599   demand_empty_rest_of_line ();
 600 }
 601
 602 static void
 603 dot_cfi_startproc (int ignored ATTRIBUTE_UNUSED)
 604 {
 605   int simple = 0;
 606
 607   if (cur_fde_data)
 608     {
 609       as_bad (_("previous CFI entry not closed (missing .cfi_endproc)"));
 610       ignore_rest_of_line ();
 611       return;
 612     }
 613
 614   cfi_new_fde (symbol_temp_new_now ());
 615
 616   SKIP_WHITESPACE ();
 617   if (is_name_beginner (*input_line_pointer))
 618     {
 619       char *name, c;
 620
 621       name = input_line_pointer;
 622       c = get_symbol_end ();
 623
 624       if (strcmp (name, "simple") == 0)
 625         {
 626           simple = 1;
 627           *input_line_pointer = c;
 628         }
 629       else
 630         input_line_pointer = name;
 631     }
 632   demand_empty_rest_of_line ();
 633
 634   cur_cfa_offset = 0;
 635   if (!simple)
 636     tc_cfi_frame_initial_instructions ();
 637 }
 638
 639 static void
 640 dot_cfi_endproc (int ignored ATTRIBUTE_UNUSED)
 641 {
 642   if (! cur_fde_data)
 643     {
 644       as_bad (_(".cfi_endproc without corresponding .cfi_startproc"));
 645       ignore_rest_of_line ();
 646       return;
 647     }
 648
 649   cfi_end_fde (symbol_temp_new_now ());
 650
 651   demand_empty_rest_of_line ();
 652 }
 653
 654 \f
 655 /* Emit a single byte into the current segment.  */
 656
 657 static inline void
 658 out_one (int byte)
 659 {
 660   FRAG_APPEND_1_CHAR (byte);
 661 }
 662
 663 /* Emit a two-byte word into the current segment.  */
 664
 665 static inline void
 666 out_two (int data)
 667 {
 668   md_number_to_chars (frag_more (2), data, 2);
 669 }
 670
 671 /* Emit a four byte word into the current segment.  */
 672
 673 static inline void
 674 out_four (int data)
 675 {
 676   md_number_to_chars (frag_more (4), data, 4);
 677 }
 678
 679 /* Emit an unsigned "little-endian base 128" number.  */
 680
 681 static void
 682 out_uleb128 (addressT value)
 683 {
 684   output_leb128 (frag_more (sizeof_leb128 (value, 0)), value, 0);
 685 }
 686
 687 /* Emit an unsigned "little-endian base 128" number.  */
 688
 689 static void
 690 out_sleb128 (offsetT value)
 691 {
 692   output_leb128 (frag_more (sizeof_leb128 (value, 1)), value, 1);
 693 }
 694
 695 static void
 696 output_cfi_insn (struct cfi_insn_data *insn)
 697 {
 698   offsetT offset;
 699   unsigned int regno;
 700
 701   switch (insn->insn)
 702     {
 703     case DW_CFA_advance_loc:
 704       {
 705         symbolS *from = insn->u.ll.lab1;
 706         symbolS *to = insn->u.ll.lab2;
 707
 708         if (symbol_get_frag (to) == symbol_get_frag (from))
 709           {
 710             addressT delta = S_GET_VALUE (to) - S_GET_VALUE (from);
 711             addressT scaled = delta / DWARF2_LINE_MIN_INSN_LENGTH;
 712
 713             if (scaled <= 0x3F)
 714               out_one (DW_CFA_advance_loc + scaled);
 715             else if (delta <= 0xFF)
 716               {
 717                 out_one (DW_CFA_advance_loc1);
 718                 out_one (delta);
 719               }
 720             else if (delta <= 0xFFFF)
 721               {
 722                 out_one (DW_CFA_advance_loc2);
 723                 out_two (delta);
 724               }
 725             else
 726               {
 727                 out_one (DW_CFA_advance_loc4);
 728                 out_four (delta);
 729               }
 730           }
 731         else
 732           {
 733             expressionS exp;
 734
 735             exp.X_op = O_subtract;
 736             exp.X_add_symbol = to;
 737             exp.X_op_symbol = from;
 738             exp.X_add_number = 0;
 739
 740             /* The code in ehopt.c expects that one byte of the encoding
 741                is already allocated to the frag.  This comes from the way
 742                that it scans the .eh_frame section looking first for the
 743                .byte DW_CFA_advance_loc4.  */
 744             frag_more (1);
 745
 746             frag_var (rs_cfa, 4, 0, DWARF2_LINE_MIN_INSN_LENGTH << 3,
 747                       make_expr_symbol (&exp), frag_now_fix () - 1,
 748                       (char *) frag_now);
 749           }
 750       }
 751       break;
 752
 753     case DW_CFA_def_cfa:
 754       offset = insn->u.ri.offset;
 755       if (offset < 0)
 756         {
 757           out_one (DW_CFA_def_cfa_sf);
 758           out_uleb128 (insn->u.ri.reg);
 759           out_sleb128 (offset / DWARF2_CIE_DATA_ALIGNMENT);
 760         }
 761       else
 762         {
 763           out_one (DW_CFA_def_cfa);
 764           out_uleb128 (insn->u.ri.reg);
 765           out_uleb128 (offset);
 766         }
 767       break;
 768
 769     case DW_CFA_def_cfa_register:
 770     case DW_CFA_undefined:
 771     case DW_CFA_same_value:
 772       out_one (insn->insn);
 773       out_uleb128 (insn->u.r);
 774       break;
 775
 776     case DW_CFA_def_cfa_offset:
 777       offset = insn->u.i;
 778       if (offset < 0)
 779         {
 780           out_one (DW_CFA_def_cfa_offset_sf);
 781           out_sleb128 (offset / DWARF2_CIE_DATA_ALIGNMENT);
 782         }
 783       else
 784         {
 785           out_one (DW_CFA_def_cfa_offset);
 786           out_uleb128 (offset);
 787         }
 788       break;
 789
 790     case DW_CFA_restore:
 791       regno = insn->u.r;
 792       if (regno <= 0x3F)
 793         {
 794           out_one (DW_CFA_restore + regno);
 795         }
 796       else
 797         {
 798           out_one (DW_CFA_restore_extended);
 799           out_uleb128 (regno);
 800         }
 801       break;
 802
 803     case DW_CFA_offset:
 804       regno = insn->u.ri.reg;
 805       offset = insn->u.ri.offset / DWARF2_CIE_DATA_ALIGNMENT;
 806       if (offset < 0)
 807         {
 808           out_one (DW_CFA_offset_extended_sf);
 809           out_uleb128 (regno);
 810           out_sleb128 (offset);
 811         }
 812       else if (regno <= 0x3F)
 813         {
 814           out_one (DW_CFA_offset + regno);
 815           out_uleb128 (offset);
 816         }
 817       else
 818         {
 819           out_one (DW_CFA_offset_extended);
 820           out_uleb128 (regno);
 821           out_uleb128 (offset);
 822         }
 823       break;
 824
 825     case DW_CFA_register:
 826       out_one (DW_CFA_register);
 827       out_uleb128 (insn->u.rr.reg1);
 828       out_uleb128 (insn->u.rr.reg2);
 829       break;
 830
 831     case DW_CFA_remember_state:
 832     case DW_CFA_restore_state:
 833       out_one (insn->insn);
 834       break;
 835
 836     case DW_CFA_GNU_window_save:
 837       out_one (DW_CFA_GNU_window_save);
 838       break;
 839
 840     case CFI_escape:
 841       {
 842         struct cfi_escape_data *e;
 843         for (e = insn->u.esc; e ; e = e->next)
 844           emit_expr (&e->exp, 1);
 845         break;
 846       }
 847
 848     default:
 849       abort ();
 850     }
 851 }
 852
 853 static void
 854 output_cie (struct cie_entry *cie)
 855 {
 856   symbolS *after_size_address, *end_address;
 857   expressionS exp;
 858   struct cfi_insn_data *i;
 859
 860   cie->start_address = symbol_temp_new_now ();
 861   after_size_address = symbol_temp_make ();
 862   end_address = symbol_temp_make ();
 863
 864   exp.X_op = O_subtract;
 865   exp.X_add_symbol = end_address;
 866   exp.X_op_symbol = after_size_address;
 867   exp.X_add_number = 0;
 868
 869   emit_expr (&exp, 4);                          /* Length.  */
 870   symbol_set_value_now (after_size_address);
 871   out_four (0);                                 /* CIE id.  */
 872   out_one (DW_CIE_VERSION);                     /* Version.  */
 873   out_one ('z');                                /* Augmentation.  */
 874   out_one ('R');
 875   if (cie->signal_frame)
 876     out_one ('S');
 877   out_one (0);
 878   out_uleb128 (DWARF2_LINE_MIN_INSN_LENGTH);    /* Code alignment.  */
 879   out_sleb128 (DWARF2_CIE_DATA_ALIGNMENT);      /* Data alignment.  */
 880   if (DW_CIE_VERSION == 1)                      /* Return column.  */
 881     out_one (cie->return_column);
 882   else
 883     out_uleb128 (cie->return_column);
 884   out_uleb128 (1);                              /* Augmentation size.  */
 885 #if defined DIFF_EXPR_OK || defined tc_cfi_emit_pcrel_expr
 886   out_one (DW_EH_PE_pcrel | DW_EH_PE_sdata4);
 887 #else
 888   out_one (DW_EH_PE_sdata4);
 889 #endif
 890
 891   if (cie->first)
 892     for (i = cie->first; i != cie->last; i = i->next)
 893       output_cfi_insn (i);
 894
 895   frag_align (2, DW_CFA_nop, 0);
 896   symbol_set_value_now (end_address);
 897 }
 898
 899 static void
 900 output_fde (struct fde_entry *fde, struct cie_entry *cie,
 901             struct cfi_insn_data *first, int align)
 902 {
 903   symbolS *after_size_address, *end_address;
 904   expressionS exp;
 905
 906   after_size_address = symbol_temp_make ();
 907   end_address = symbol_temp_make ();
 908
 909   exp.X_op = O_subtract;
 910   exp.X_add_symbol = end_address;
 911   exp.X_op_symbol = after_size_address;
 912   exp.X_add_number = 0;
 913   emit_expr (&exp, 4);                          /* Length.  */
 914   symbol_set_value_now (after_size_address);
 915
 916   exp.X_add_symbol = after_size_address;
 917   exp.X_op_symbol = cie->start_address;
 918   emit_expr (&exp, 4);                          /* CIE offset.  */
 919
 920 #ifdef DIFF_EXPR_OK
 921   exp.X_add_symbol = fde->start_address;
 922   exp.X_op_symbol = symbol_temp_new_now ();
 923   emit_expr (&exp, 4);                          /* Code offset.  */
 924 #else
 925   exp.X_op = O_symbol;
 926   exp.X_add_symbol = fde->start_address;
 927   exp.X_op_symbol = NULL;
 928 #ifdef tc_cfi_emit_pcrel_expr
 929   tc_cfi_emit_pcrel_expr (&exp, 4);             /* Code offset.  */
 930 #else
 931   emit_expr (&exp, 4);                          /* Code offset.  */
 932 #endif
 933   exp.X_op = O_subtract;
 934 #endif
 935
 936   exp.X_add_symbol = fde->end_address;
 937   exp.X_op_symbol = fde->start_address;         /* Code length.  */
 938   emit_expr (&exp, 4);
 939
 940   out_uleb128 (0);                              /* Augmentation size.  */
 941
 942   for (; first; first = first->next)
 943     output_cfi_insn (first);
 944
 945   frag_align (align, DW_CFA_nop, 0);
 946   symbol_set_value_now (end_address);
 947 }
 948
 949 static struct cie_entry *
 950 select_cie_for_fde (struct fde_entry *fde, struct cfi_insn_data **pfirst)
 951 {
 952   struct cfi_insn_data *i, *j;
 953   struct cie_entry *cie;
 954
 955   for (cie = cie_root; cie; cie = cie->next)
 956     {
 957       if (cie->return_column != fde->return_column
 958           || cie->signal_frame != fde->signal_frame)
 959         continue;
 960       for (i = cie->first, j = fde->data;
 961            i != cie->last && j != NULL;
 962            i = i->next, j = j->next)
 963         {
 964           if (i->insn != j->insn)
 965             goto fail;
 966           switch (i->insn)
 967             {
 968             case DW_CFA_advance_loc:
 969             case DW_CFA_remember_state:
 970               /* We reached the first advance/remember in the FDE,
 971                  but did not reach the end of the CIE list.  */
 972               goto fail;
 973
 974             case DW_CFA_offset:
 975             case DW_CFA_def_cfa:
 976               if (i->u.ri.reg != j->u.ri.reg)
 977                 goto fail;
 978               if (i->u.ri.offset != j->u.ri.offset)
 979                 goto fail;
 980               break;
 981
 982             case DW_CFA_register:
 983               if (i->u.rr.reg1 != j->u.rr.reg1)
 984                 goto fail;
 985               if (i->u.rr.reg2 != j->u.rr.reg2)
 986                 goto fail;
 987               break;
 988
 989             case DW_CFA_def_cfa_register:
 990             case DW_CFA_restore:
 991             case DW_CFA_undefined:
 992             case DW_CFA_same_value:
 993               if (i->u.r != j->u.r)
 994                 goto fail;
 995               break;
 996
 997             case DW_CFA_def_cfa_offset:
 998               if (i->u.i != j->u.i)
 999                 goto fail;
1000               break;
1001
1002             case CFI_escape:
1003               /* Don't bother matching these for now.  */
1004               goto fail;
1005
1006             default:
1007               abort ();
1008             }
1009         }
1010
1011       /* Success if we reached the end of the CIE list, and we've either
1012          run out of FDE entries or we've encountered an advance,
1013          remember, or escape.  */
1014       if (i == cie->last
1015           && (!j
1016               || j->insn == DW_CFA_advance_loc
1017               || j->insn == DW_CFA_remember_state
1018               || j->insn == CFI_escape))
1019         {
1020           *pfirst = j;
1021           return cie;
1022         }
1023
1024     fail:;
1025     }
1026
1027   cie = xmalloc (sizeof (struct cie_entry));
1028   cie->next = cie_root;
1029   cie_root = cie;
1030   cie->return_column = fde->return_column;
1031   cie->signal_frame = fde->signal_frame;
1032   cie->first = fde->data;
1033
1034   for (i = cie->first; i ; i = i->next)
1035     if (i->insn == DW_CFA_advance_loc
1036         || i->insn == DW_CFA_remember_state
1037         || i->insn == CFI_escape)
1038       break;
1039
1040   cie->last = i;
1041   *pfirst = i;
1042
1043   output_cie (cie);
1044
1045   return cie;
1046 }
1047
1048 void
1049 cfi_finish (void)
1050 {
1051   segT cfi_seg;
1052   struct fde_entry *fde;
1053   int save_flag_traditional_format;
1054
1055   if (cur_fde_data)
1056     {
1057       as_bad (_("open CFI at the end of file; missing .cfi_endproc directive"));
1058       cur_fde_data->end_address = cur_fde_data->start_address;
1059     }
1060
1061   if (all_fde_data == 0)
1062     return;
1063
1064   /* Open .eh_frame section.  */
1065   cfi_seg = subseg_new (".eh_frame", 0);
1066   bfd_set_section_flags (stdoutput, cfi_seg,
1067                          SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_READONLY);
1068   subseg_set (cfi_seg, 0);
1069   record_alignment (cfi_seg, EH_FRAME_ALIGNMENT);
1070
1071   /* Make sure check_eh_frame doesn't do anything with our output.  */
1072   save_flag_traditional_format = flag_traditional_format;
1073   flag_traditional_format = 1;
1074
1075   for (fde = all_fde_data; fde ; fde = fde->next)
1076     {
1077       struct cfi_insn_data *first;
1078       struct cie_entry *cie;
1079
1080       cie = select_cie_for_fde (fde, &first);
1081       output_fde (fde, cie, first, fde->next == NULL ? EH_FRAME_ALIGNMENT : 2);
1082     }
1083
1084   flag_traditional_format = save_flag_traditional_format;
1085 }