gas/dwarf2dbg.c

   1 /* dwarf2dbg.c - DWARF2 debug support
   2    Copyright (C) 1999, 2000 Free Software Foundation, Inc.
   3    Contributed by David Mosberger-Tang <davidm@hpl.hp.com>
   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, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 /* Logical line numbers can be controlled by the compiler via the
  23    following two directives:
  24
  25         .file FILENO "file.c"
  26         .loc  FILENO LINENO [COLUMN]
  27
  28    FILENO is the filenumber.  */
  29
  30 #include "ansidecl.h"
  31
  32 #include "as.h"
  33 #include "dwarf2dbg.h"
  34 #include "subsegs.h"
  35
  36 #include "elf/dwarf2.h"
  37
  38 /* Since we can't generate the prolog until the body is complete, we
  39    use three different subsegments for .debug_line: one holding the
  40    prolog, one for the directory and filename info, and one for the
  41    body ("statement program").  */
  42 #define DL_PROLOG       0
  43 #define DL_FILES        1
  44 #define DL_BODY         2
  45
  46 /* First special line opcde - leave room for the standard opcodes.
  47    Note: If you want to change this, you'll have to update the
  48    "standard_opcode_lengths" table that is emitted below in
  49    dwarf2_finish().  */
  50 #define DWARF2_LINE_OPCODE_BASE         10
  51
  52 #ifndef DWARF2_LINE_BASE
  53   /* Minimum line offset in a special line info. opcode.  This value
  54      was chosen to give a reasonable range of values.  */
  55 # define DWARF2_LINE_BASE               -5
  56 #endif
  57
  58 /* Range of line offsets in a special line info. opcode.  */
  59 #ifndef DWARF2_LINE_RANGE
  60 # define DWARF2_LINE_RANGE              14
  61 #endif
  62
  63 #ifndef DWARF2_LINE_MIN_INSN_LENGTH
  64   /* Define the architecture-dependent minimum instruction length (in
  65      bytes).  This value should be rather too small than too big.  */
  66 # define DWARF2_LINE_MIN_INSN_LENGTH    4
  67 #endif
  68
  69 /* Flag that indicates the initial value of the is_stmt_start flag.
  70    In the present implementation, we do not mark any lines as
  71    the beginning of a source statement, because that information
  72    is not made available by the GCC front-end.  */
  73 #define DWARF2_LINE_DEFAULT_IS_STMT     1
  74
  75 /* Flag that indicates the initial value of the is_stmt_start flag.
  76    In the present implementation, we do not mark any lines as
  77    the beginning of a source statement, because that information
  78    is not made available by the GCC front-end.  */
  79 #define DWARF2_LINE_DEFAULT_IS_STMT     1
  80
  81 /* Given a special op, return the line skip amount.  */
  82 #define SPECIAL_LINE(op) \
  83         (((op) - DWARF2_LINE_OPCODE_BASE)%DWARF2_LINE_RANGE + DWARF2_LINE_BASE)
  84
  85 /* Given a special op, return the address skip amount (in units of
  86    DWARF2_LINE_MIN_INSN_LENGTH.  */
  87 #define SPECIAL_ADDR(op) (((op) - DWARF2_LINE_OPCODE_BASE)/DWARF2_LINE_RANGE)
  88
  89 /* The maximum address skip amount that can be encoded with a special op.  */
  90 #define MAX_SPECIAL_ADDR_DELTA          SPECIAL_ADDR(255)
  91
  92 #define INITIAL_STATE                                           \
  93   /* Initialize as per DWARF2.0 standard.  */                   \
  94   0,                                    /* address */           \
  95   1,                                    /* file */              \
  96   1,                                    /* line */              \
  97   0,                                    /* column */            \
  98   DWARF2_LINE_DEFAULT_IS_STMT,          /* is_stmt */           \
  99   0,                                    /* basic_block */       \
 100   1                                     /* empty_sequence */
 101
 102 static struct
 103   {
 104     /* state machine state as per DWARF2 manual: */
 105     struct dwarf2_sm
 106       {
 107         addressT addr;
 108         unsigned int filenum;
 109         unsigned int line;
 110         unsigned int column;
 111         unsigned int
 112           is_stmt : 1,
 113           basic_block : 1,
 114           empty_sequence : 1;           /* current code sequence has no DWARF2 directives? */
 115       }
 116     sm;
 117
 118     unsigned int
 119       any_dwarf2_directives : 1;        /* did we emit any DWARF2 line debug directives? */
 120
 121     fragS * frag;       /* frag that "addr" is relative to */
 122     segT text_seg;      /* text segment "addr" is relative to */
 123     subsegT text_subseg;
 124     segT line_seg;      /* ".debug_line" segment */
 125     int last_filename;  /* index of last filename that was used */
 126     int num_filenames;  /* index of last filename in use */
 127     int filename_len;   /* length of the filename array */
 128     struct
 129       {
 130         int dir;        /* valid after gen_dir_list() only */
 131         char *name; /* full path before gen_dir_list(), filename afterwards */
 132       }
 133     *file;
 134
 135     struct dwarf2_line_info current;    /* current source info: */
 136
 137     /* counters for statistical purposes: */
 138     unsigned int num_line_entries;
 139     unsigned int opcode_hist[256];      /* histogram of opcode frequencies */
 140   }
 141 ls =
 142   {
 143     {
 144       INITIAL_STATE
 145     },
 146     0,
 147     0,
 148     0,
 149     0,
 150     0,
 151     0,
 152     0,
 153     0,
 154     NULL,
 155     { NULL, 0, 0, 0, 0 },
 156     0,
 157     {
 158       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 159       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 160       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 161       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 162       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 163       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 164       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 165       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 166       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 167       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 168       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 169       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 170       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 171       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 172       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 173       0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 174     }
 175   };
 176
 177
 178 /* Function prototypes: */
 179 static void out_uleb128 PARAMS ((addressT));
 180 static void out_sleb128 PARAMS ((offsetT));
 181 static void gen_addr_line PARAMS ((int, addressT));
 182 static void reset_state_machine PARAMS ((void));
 183 static void out_set_addr PARAMS ((addressT));
 184 static void out_end_sequence PARAMS ((void));
 185 static int get_filenum PARAMS ((int, char *));
 186 static void gen_dir_list PARAMS ((void));
 187 static void gen_file_list PARAMS ((void));
 188 static void print_stats PARAMS ((unsigned long));
 189
 190
 191 #define out_byte(byte)  FRAG_APPEND_1_CHAR(byte)
 192 #define out_opcode(opc) (out_byte ((opc)), ++ls.opcode_hist[(opc) & 0xff])
 193
 194 /* Output an unsigned "little-endian base 128" number.  */
 195 static void
 196 out_uleb128 (value)
 197      addressT value;
 198 {
 199   unsigned char byte, more = 0x80;
 200
 201   do
 202     {
 203       byte = value & 0x7f;
 204       value >>= 7;
 205       if (value == 0)
 206         more = 0;
 207       out_byte (more | byte);
 208     }
 209   while (more);
 210 }
 211
 212 /* Output a signed "little-endian base 128" number.  */
 213 static void
 214 out_sleb128 (value)
 215      offsetT value;
 216 {
 217   unsigned char byte, more = 0x80;
 218
 219   do
 220     {
 221       byte = value & 0x7f;
 222       value >>= 7;
 223       if (((value == 0) && ((byte & 0x40) == 0))
 224           || ((value == -1) && ((byte & 0x40) != 0)))
 225         more = 0;
 226       out_byte (more | byte);
 227     }
 228   while (more);
 229 }
 230
 231 /* Encode a pair of line and address skips as efficiently as possible.
 232    Note that the line skip is signed, whereas the address skip is
 233    unsigned.  */
 234 static void
 235 gen_addr_line (line_delta, addr_delta)
 236      int line_delta;
 237      addressT addr_delta;
 238 {
 239   unsigned int tmp, opcode;
 240
 241   tmp = line_delta - DWARF2_LINE_BASE;
 242
 243   if (tmp >= DWARF2_LINE_RANGE)
 244     {
 245       out_opcode (DW_LNS_advance_line);
 246       out_sleb128 (line_delta);
 247       tmp = 0 - DWARF2_LINE_BASE;
 248       line_delta = 0;
 249     }
 250
 251   tmp += DWARF2_LINE_OPCODE_BASE;
 252
 253   /* try using a special opcode: */
 254   opcode = tmp + addr_delta*DWARF2_LINE_RANGE;
 255   if (opcode <= 255)
 256     {
 257       out_opcode (opcode);
 258       return;
 259     }
 260
 261   /* try using DW_LNS_const_add_pc followed by special op: */
 262   opcode = tmp + (addr_delta - MAX_SPECIAL_ADDR_DELTA)*DWARF2_LINE_RANGE;
 263   if (opcode <= 255)
 264     {
 265       out_opcode (DW_LNS_const_add_pc);
 266       out_opcode (opcode);
 267       return;
 268     }
 269
 270   out_opcode (DW_LNS_advance_pc);
 271   out_uleb128 (addr_delta);
 272
 273   if (line_delta)
 274     out_opcode (tmp);           /* output line-delta */
 275   else
 276     out_opcode (DW_LNS_copy);   /* append new row with current info */
 277 }
 278
 279 static void
 280 reset_state_machine ()
 281 {
 282   static const struct dwarf2_sm initial_state = { INITIAL_STATE };
 283
 284   ls.sm = initial_state;
 285 }
 286
 287 /* Set an absolute address (may results in a relocation entry): */
 288 static void
 289 out_set_addr (addr)
 290      addressT addr;
 291 {
 292   subsegT saved_subseg;
 293   segT saved_seg;
 294   expressionS expr;
 295   symbolS *sym;
 296   int bytes_per_address;
 297
 298   saved_seg = now_seg;
 299   saved_subseg = now_subseg;
 300
 301   subseg_set (ls.text_seg, ls.text_subseg);
 302   sym = symbol_new (".L0\001", now_seg, addr, frag_now);
 303
 304   subseg_set (saved_seg, saved_subseg);
 305
 306 #ifdef BFD_ASSEMBLER
 307   bytes_per_address = bfd_arch_bits_per_address (stdoutput) / 8;
 308 #else
 309   /* FIXME.  */
 310   bytes_per_address = 4;
 311 #endif
 312
 313   out_opcode (DW_LNS_extended_op);
 314   out_uleb128 (bytes_per_address + 1);
 315
 316   out_opcode (DW_LNE_set_address);
 317   expr.X_op = O_symbol;
 318   expr.X_add_symbol = sym;
 319   expr.X_add_number = 0;
 320   emit_expr (&expr, bytes_per_address);
 321 }
 322
 323 /* Emit DW_LNS_end_sequence and reset state machine.  Does not
 324    preserve the current segment/sub-segment!  */
 325 static void
 326 out_end_sequence ()
 327 {
 328   addressT addr, delta;
 329   fragS *text_frag;
 330
 331   if (ls.text_seg)
 332     {
 333       subseg_set (ls.text_seg, ls.text_subseg);
 334 #ifdef md_current_text_addr
 335       addr = md_current_text_addr ();
 336 #else
 337       addr = frag_now_fix ();
 338 #endif
 339       text_frag = frag_now;
 340       subseg_set (ls.line_seg, DL_BODY);
 341       if (text_frag != ls.frag)
 342         {
 343           out_set_addr (addr);
 344           ls.sm.addr = addr;
 345           ls.frag = text_frag;
 346         }
 347       else
 348         {
 349           delta = (addr - ls.sm.addr) / DWARF2_LINE_MIN_INSN_LENGTH;
 350           if (delta > 0)
 351             {
 352               /* Advance address without updating the line-debug
 353                  matrix---the end_sequence entry is used only to tell
 354                  the debugger the end of the sequence.*/
 355               out_opcode (DW_LNS_advance_pc);
 356               out_uleb128 (delta);
 357             }
 358         }
 359     }
 360   else
 361     subseg_set (ls.line_seg, DL_BODY);
 362
 363   out_opcode (DW_LNS_extended_op);
 364   out_uleb128 (1);
 365   out_byte (DW_LNE_end_sequence);
 366
 367   reset_state_machine ();
 368 }
 369
 370 /* Look up a filenumber either by filename or by filenumber.  If both
 371    a filenumber and a filename are specified, lookup by filename takes
 372    precedence.  If the filename cannot be found, it is added to the
 373    filetable and the filenumber for the new entry is returned.  */
 374 static int
 375 get_filenum (filenum, file)
 376      int filenum;
 377      char *file;
 378 {
 379   int i, last = filenum - 1;
 380   char char0 = file[0];
 381
 382   /* If filenum is out of range of the filename table, then try using the
 383      table entry returned from the previous call.  */
 384   if (last >= ls.num_filenames || last < 0)
 385     last = ls.last_filename;
 386
 387   /* Do a quick check against the specified or previously used filenum.  */
 388   if (ls.num_filenames > 0 && ls.file[last].name[0] == char0
 389       && strcmp (ls.file[last].name + 1, file + 1) == 0)
 390     return last + 1;
 391
 392   /* no match, fall back to simple linear scan: */
 393   for (i = 0; i < ls.num_filenames; ++i)
 394     {
 395       if (ls.file[i].name[0] == char0
 396           && strcmp (ls.file[i].name + 1, file + 1) == 0)
 397         {
 398           ls.last_filename = i;
 399           return i + 1;
 400         }
 401     }
 402
 403   /* no match: enter new filename */
 404   if (ls.num_filenames >= ls.filename_len)
 405     {
 406       ls.filename_len += 13;
 407       ls.file = xrealloc (ls.file, ls.filename_len * sizeof (ls.file[0]));
 408     }
 409   ls.file[ls.num_filenames].dir = 0;
 410   ls.file[ls.num_filenames].name = file;
 411   ls.last_filename = ls.num_filenames;
 412   return ++ls.num_filenames;
 413 }
 414
 415 /* Emit an entry in the line number table if the address or line has changed.
 416    ADDR is relative to the current frag in the text section.  */
 417
 418 void
 419 dwarf2_gen_line_info (addr, l)
 420      addressT addr;
 421      struct dwarf2_line_info *l;
 422 {
 423   unsigned int filenum = l->filenum;
 424   unsigned int any_output = 0;
 425   subsegT saved_subseg;
 426   segT saved_seg;
 427   fragS *saved_frag;
 428
 429   if (flag_debug)
 430     fprintf (stderr, "line: addr %lx file `%s' line %u col %u flags %x\n",
 431              (unsigned long) addr, l->filename, l->line, l->column, l->flags);
 432
 433   if (filenum > 0 && !l->filename)
 434     {
 435       if (filenum >= (unsigned int) ls.num_filenames)
 436         {
 437           as_warn ("Encountered bad file number in line number debug info!");
 438           return;
 439         }
 440     }
 441   else if (l->filename)
 442     filenum = get_filenum (filenum, l->filename);
 443   else
 444     return;     /* no filename, no filnum => no play */
 445
 446   /* Must save these before the subseg_new call, as that call will change
 447      them.  */
 448   saved_seg = now_seg;
 449   saved_subseg = now_subseg;
 450   saved_frag = frag_now;
 451
 452   if (!ls.line_seg)
 453     {
 454 #ifdef BFD_ASSEMBLER
 455       symbolS *secsym;
 456 #endif
 457
 458       ls.line_seg = subseg_new (".debug_line", 0);
 459
 460 #ifdef BFD_ASSEMBLER
 461       bfd_set_section_flags (stdoutput, ls.line_seg, SEC_READONLY);
 462
 463       /* We're going to need this symbol.  */
 464       secsym = symbol_find (".debug_line");
 465       if (secsym != NULL)
 466         symbol_set_bfdsym (secsym, ls.line_seg->symbol);
 467       else
 468         symbol_table_insert (section_symbol (ls.line_seg));
 469 #endif
 470     }
 471
 472   subseg_set (ls.line_seg, DL_BODY);
 473
 474   if (ls.text_seg != saved_seg || ls.text_subseg != saved_subseg)
 475     {
 476       if (!ls.sm.empty_sequence)
 477         {
 478           out_end_sequence ();          /* terminate previous sequence */
 479           ls.sm.empty_sequence = 1;
 480         }
 481       any_output = 1;
 482       ls.text_seg = saved_seg;
 483       ls.text_subseg = saved_subseg;
 484       out_set_addr (addr);
 485       ls.sm.addr = addr;
 486       ls.frag = saved_frag;
 487     }
 488
 489   if (ls.sm.filenum != filenum)
 490     {
 491       any_output = 1;
 492       out_opcode (DW_LNS_set_file);
 493       out_uleb128 (filenum);
 494       ls.sm.filenum = filenum;
 495     }
 496
 497   if (ls.sm.column != l->column)
 498     {
 499       any_output = 1;
 500       out_opcode (DW_LNS_set_column);
 501       out_uleb128 (l->column);
 502       ls.sm.column = l->column;
 503     }
 504
 505   if (((l->flags & DWARF2_FLAG_BEGIN_STMT) != 0) != ls.sm.is_stmt)
 506     {
 507       any_output = 1;
 508       out_opcode (DW_LNS_negate_stmt);
 509     }
 510
 511   if (l->flags & DWARF2_FLAG_BEGIN_BLOCK)
 512     {
 513       any_output = 1;
 514       out_opcode (DW_LNS_set_basic_block);
 515     }
 516
 517   if (ls.sm.line != l->line)
 518     {
 519       any_output = 1;
 520       if (saved_frag != ls.frag)
 521         {
 522           /* If a new frag got allocated (for whatever reason), then
 523              deal with it by generating a reference symbol.  Note: no
 524              end_sequence needs to be generated because the address did
 525              not really decrease (only the reference point changed).  */
 526           out_set_addr (addr);
 527           ls.sm.addr = addr;
 528           ls.frag = saved_frag;
 529         }
 530       gen_addr_line (l->line - ls.sm.line,
 531                      (addr - ls.sm.addr) / DWARF2_LINE_MIN_INSN_LENGTH);
 532       ls.sm.basic_block = 0;
 533       ls.sm.line = l->line;
 534       ls.sm.addr = addr;
 535     }
 536
 537   subseg_set (saved_seg, saved_subseg);
 538
 539   ls.num_line_entries += any_output;
 540   if (any_output)
 541     ls.sm.empty_sequence = 0;
 542 }
 543
 544 static void
 545 gen_dir_list ()
 546 {
 547   char *str, *slash, *dir_list, *dp, *cp;
 548   int i, j, num_dirs;
 549
 550   dir_list = frag_more (0);
 551   num_dirs = 0;
 552
 553   for (i = 0; i < ls.num_filenames; ++i)
 554     {
 555       str = ls.file[i].name;
 556       slash = strrchr (str, '/');
 557       if (slash)
 558         {
 559           *slash = '\0';
 560           for (j = 0, dp = dir_list; j < num_dirs; ++j)
 561             {
 562               if (strcmp (str, dp) == 0)
 563                 {
 564                   ls.file[i].dir = j + 1;
 565                   break;
 566                 }
 567               dp += strlen (dp);
 568             }
 569           if (j >= num_dirs)
 570             {
 571               /* didn't find this directory: append it to the list */
 572               size_t size = strlen (str) + 1;
 573               cp = frag_more (size);
 574               memcpy (cp, str, size);
 575               ls.file[i].dir = ++num_dirs;
 576             }
 577           *slash = '/';
 578           ls.file[i].name = slash + 1;
 579         }
 580     }
 581   out_byte ('\0');      /* terminate directory list */
 582 }
 583
 584 static void
 585 gen_file_list ()
 586 {
 587   size_t size;
 588   char *cp;
 589   int i;
 590
 591   for (i = 0; i < ls.num_filenames; ++i)
 592     {
 593       size = strlen (ls.file[i].name) + 1;
 594       cp = frag_more (size);
 595       memcpy (cp, ls.file[i].name, size);
 596
 597       out_uleb128 (ls.file[i].dir);     /* directory number */
 598       out_uleb128 (0);                  /* last modification timestamp */
 599       out_uleb128 (0);                  /* filesize */
 600     }
 601   out_byte (0);         /* terminate filename list */
 602 }
 603
 604 static void
 605 print_stats (total_size)
 606      unsigned long total_size;
 607 {
 608   static const char *opc_name[] =
 609     {
 610       "extended", "copy", "advance_pc", "advance_line", "set_file",
 611       "set_column", "negate_stmt", "set_basic_block", "const_add_pc",
 612       "fixed_advance_pc"
 613     };
 614   size_t i;
 615   int j;
 616
 617   fprintf (stderr, "Average size: %g bytes/line\n",
 618            total_size / (double) ls.num_line_entries);
 619
 620   fprintf (stderr, "\nStandard opcode histogram:\n");
 621
 622   for (i = 0; i < sizeof (opc_name)/sizeof (opc_name[0]); ++i)
 623     {
 624       fprintf (stderr, "%s", opc_name[i]);
 625       for (j = strlen (opc_name[i]); j < 16; ++j)
 626         fprintf (stderr, " ");
 627       fprintf (stderr, ": %u\n", ls.opcode_hist[i]);
 628     }
 629
 630   fprintf (stderr, "\nSpecial opcodes:\naddr\t\t\t\tline skip\n");
 631
 632   fprintf (stderr, "skip: ");
 633   for (j = DWARF2_LINE_BASE; j < DWARF2_LINE_BASE + DWARF2_LINE_RANGE; ++j)
 634     fprintf (stderr, "%3d", j);
 635   fprintf (stderr, "\n-----");
 636
 637   for (; i < 256; ++i)
 638     {
 639       j = SPECIAL_LINE (i);
 640       if (j == DWARF2_LINE_BASE)
 641         fprintf (stderr, "\n%4u: ",
 642                  ((unsigned int)
 643                   DWARF2_LINE_MIN_INSN_LENGTH * SPECIAL_ADDR (i)));
 644       fprintf (stderr, " %2u", ls.opcode_hist[i]);
 645     }
 646   fprintf (stderr, "\n");
 647 }
 648
 649 void
 650 dwarf2_finish ()
 651 {
 652   addressT body_size, total_size, prolog_size;
 653   subsegT saved_subseg;
 654   segT saved_seg;
 655   char *cp;
 656
 657   if (!ls.line_seg)
 658     /* no .debug_line segment, no work to do... */
 659     return;
 660
 661   saved_seg = now_seg;
 662   saved_subseg = now_subseg;
 663
 664   if (!ls.sm.empty_sequence)
 665     out_end_sequence ();
 666   total_size = body_size = frag_now_fix ();
 667
 668   /* now generate the directory and file lists: */
 669   subseg_set (ls.line_seg, DL_FILES);
 670   gen_dir_list ();
 671   gen_file_list ();
 672   total_size += frag_now_fix ();
 673
 674   /* and now the header ("statement program prolog", in DWARF2 lingo...) */
 675   subseg_set (ls.line_seg, DL_PROLOG);
 676
 677   cp = frag_more (15 + DWARF2_LINE_OPCODE_BASE - 1);
 678
 679   total_size += frag_now_fix ();
 680   prolog_size = total_size - body_size - 10;
 681
 682 # define STUFF(val,size)        md_number_to_chars (cp, val, size); cp += size;
 683   STUFF (total_size - 4, 4);    /* length */
 684   STUFF (2, 2);                 /* version */
 685   STUFF (prolog_size, 4);       /* prologue_length */
 686   STUFF (DWARF2_LINE_MIN_INSN_LENGTH, 1);
 687   STUFF (DWARF2_LINE_DEFAULT_IS_STMT, 1);
 688   STUFF (DWARF2_LINE_BASE, 1);
 689   STUFF (DWARF2_LINE_RANGE, 1);
 690   STUFF (DWARF2_LINE_OPCODE_BASE, 1);
 691
 692   /* standard_opcode_lengths: */
 693   STUFF (0, 1);                 /* DW_LNS_copy */
 694   STUFF (1, 1);                 /* DW_LNS_advance_pc */
 695   STUFF (1, 1);                 /* DW_LNS_advance_line */
 696   STUFF (1, 1);                 /* DW_LNS_set_file */
 697   STUFF (1, 1);                 /* DW_LNS_set_column */
 698   STUFF (0, 1);                 /* DW_LNS_negate_stmt */
 699   STUFF (0, 1);                 /* DW_LNS_set_basic_block */
 700   STUFF (0, 1);                 /* DW_LNS_const_add_pc */
 701   STUFF (1, 1);                 /* DW_LNS_fixed_advance_pc */
 702
 703   subseg_set (saved_seg, saved_subseg);
 704
 705   if (flag_debug)
 706     print_stats (total_size);
 707 }
 708
 709 void
 710 dwarf2_directive_file (dummy)
 711      int dummy ATTRIBUTE_UNUSED;
 712 {
 713   int len;
 714
 715   /* Continue to accept a bare string and pass it off.  */
 716   SKIP_WHITESPACE ();
 717   if (*input_line_pointer == '"')
 718     {
 719       s_app_file (0);
 720       return;
 721     }
 722
 723   ls.any_dwarf2_directives = 1;
 724
 725   if (debug_type == DEBUG_NONE)
 726     /* Automatically turn on DWARF2 debug info unless something else
 727        has been selected.  */
 728     debug_type = DEBUG_DWARF2;
 729
 730   ls.current.filenum = get_absolute_expression ();
 731   ls.current.filename = demand_copy_C_string (&len);
 732
 733   demand_empty_rest_of_line ();
 734 }
 735
 736 void
 737 dwarf2_directive_loc (dummy)
 738      int dummy ATTRIBUTE_UNUSED;
 739 {
 740   ls.any_dwarf2_directives = 1;
 741
 742   ls.current.filenum = get_absolute_expression ();
 743   SKIP_WHITESPACE ();
 744   ls.current.line = get_absolute_expression ();
 745   SKIP_WHITESPACE ();
 746   ls.current.column = get_absolute_expression ();
 747   demand_empty_rest_of_line ();
 748
 749   ls.current.flags = DWARF2_FLAG_BEGIN_STMT;
 750
 751 #ifndef NO_LISTING
 752   if (listing)
 753     listing_source_line (ls.current.line);
 754 #endif
 755 }
 756
 757 void
 758 dwarf2_where (line)
 759      struct dwarf2_line_info *line;
 760 {
 761   if (ls.any_dwarf2_directives)
 762     *line = ls.current;
 763   else
 764     {
 765       as_where (&line->filename, &line->line);
 766       line->filenum = 0;
 767       line->column = 0;
 768       line->flags = DWARF2_FLAG_BEGIN_STMT;
 769     }
 770 }