gcc/bc-emit.c

   1 /* Output bytecodes for GNU C-compiler.
   2    Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC 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 2, or (at your option)
   9 any later version.
  10
  11 GNU CC 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 GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include "config.h"
  23 #ifdef __STDC__
  24 #include <stdarg.h>
  25 #else
  26 #include <varargs.h>
  27 #endif
  28 #include "machmode.h"
  29 #include "rtl.h"
  30 #include "real.h"
  31 #include "obstack.h"
  32 #include "bytecode.h"
  33 #ifdef __GNUC__
  34 #include "bytetypes.h"
  35 #endif
  36 #include "bc-emit.h"
  37 #include "bc-opcode.h"
  38 #include "bc-typecd.h"
  39 #include "bi-run.h"
  40
  41 #include <stdio.h>
  42
  43 extern char *xmalloc (), *xrealloc ();
  44 extern void free ();
  45
  46 extern struct obstack *rtl_obstack;
  47
  48 /* Indexed by mode class, gives the narrowest mode for each class.  */
  49
  50 extern enum machine_mode class_narrowest_mode[(int) MAX_MODE_CLASS];
  51
  52 /* Commonly used modes.  */
  53 /* Mode whose width is BITS_PER_UNIT */
  54 extern enum machine_mode byte_mode;
  55
  56 /* Mode whose width is BITS_PER_WORD */
  57 extern enum machine_mode word_mode;
  58
  59 /* Vector indexed by opcode giving info about the args for each opcode. */
  60 static struct arityvec arityvec[] = {
  61 #include "bc-arity.h"
  62 };
  63
  64 /* How to print a symbol name for the assembler.  */
  65 static void
  66 prsym (file, s)
  67      FILE *file;
  68      char *s;
  69 {
  70   if (*s == '*')
  71     fprintf (file, "%s", s + 1);
  72   else
  73
  74 #ifdef NAMES_HAVE_UNDERSCORES
  75     fprintf (file, "_%s", s);
  76 #else
  77     fprintf (file, "%s", s);
  78 #endif
  79
  80 }
  81
  82 /* Maintain a bucket hash table for symbol names. */
  83
  84 #define HASH_BITS 32
  85 #define HASH_SIZE 509
  86
  87 static struct bc_sym *hashtab[HASH_SIZE];
  88
  89 static unsigned int
  90 hash (name)
  91      char *name;
  92 {
  93   unsigned int hash = 0;
  94
  95   while (*name)
  96     {
  97       hash = hash << 3 | hash >> HASH_BITS - 3;
  98       hash += *name++;
  99     }
 100
 101   return hash % HASH_SIZE;
 102 }
 103
 104
 105 /* Look up the named symbol, creating it if it doesn't exist. */
 106 struct bc_sym *
 107 sym_lookup (name)
 108      char *name;
 109 {
 110   int i;
 111   struct bc_sym *s;
 112
 113   i = hash (name);
 114   for (s = hashtab[i]; s; s = s->next)
 115     if (!strcmp (s->name, name))
 116       return s;
 117
 118   s = (struct bc_sym *) xmalloc (sizeof (struct bc_sym));
 119   s->name = xmalloc (strlen (name) + 1);
 120   strcpy (s->name, name);
 121   s->defined = s->global = s->common = 0;
 122   s->val = 0;
 123   s->next = hashtab[i];
 124   hashtab[i] = s;
 125   return s;
 126 }
 127
 128
 129 /* Write out .globl and common symbols to the named file.  */
 130 static void
 131 bc_sym_write (file)
 132      FILE *file;
 133 {
 134   int i;
 135   struct bc_sym *s;
 136
 137   for (i = 0; i < HASH_SIZE; ++i)
 138     for (s = hashtab[i]; s; s = s->next)
 139       {
 140         if (s->global)
 141           {
 142             fprintf (file, "\n\t.globl ");
 143             prsym (file, s->name);
 144             putc ('\n', file);
 145             if (s->common)
 146               {
 147                 fprintf (file, "\n\t.comm ");
 148                 prsym (file, s->name);
 149                 fprintf (file, ", %lu\n", s->val);
 150               }
 151           }
 152         else if (s->common)
 153           {
 154             fprintf (file, "\n\t.lcomm ");
 155             prsym (file, s->name);
 156             fprintf (file, ", %lu\n", s->val);
 157           }
 158       }
 159 }
 160
 161 \f
 162
 163
 164 /* Create and initialize a new segment. */
 165 static struct bc_seg *
 166 seg_create ()
 167 {
 168   struct bc_seg *result;
 169
 170   result = (struct bc_seg *) xmalloc (sizeof (struct bc_seg));
 171   result->alloc = 256;
 172   result->data = xmalloc (result->alloc);
 173   result->size = 0;
 174   result->syms = 0;
 175   result->relocs = 0;
 176   return result;
 177 }
 178
 179
 180 /* Advance the segment index to the next alignment boundary. */
 181 static void
 182 seg_align (seg, log)
 183      struct bc_seg *seg;
 184      int log;
 185 {
 186   unsigned int oldsize = seg->size;
 187
 188   seg->size = seg->size + (1 << log) - 1 & ~((1 << log) - 1);
 189   if (seg->size > seg->alloc)
 190     {
 191       while (seg->size > seg->alloc)
 192         seg->alloc *= 2;
 193       seg->data = xrealloc (seg->data, seg->alloc);
 194     }
 195   bzero (seg->data + oldsize, seg->size - oldsize);
 196 }
 197
 198
 199 /* Append the given data to the given segment. */
 200 static void
 201 seg_data (seg, data, size)
 202      struct bc_seg *seg;
 203      char *data;
 204      unsigned int size;
 205 {
 206   if (seg->size + size > seg->alloc)
 207     {
 208       while (seg->size + size > seg->alloc)
 209         seg->alloc *= 2;
 210       seg->data = xrealloc (seg->data, seg->alloc);
 211     }
 212
 213   bcopy (data, seg->data + seg->size, size);
 214   seg->size += size;
 215 }
 216
 217
 218 /* Append a zero-filled skip to the given segment.  */
 219 static void
 220 seg_skip (seg, size)
 221      struct bc_seg *seg;
 222      unsigned int size;
 223 {
 224   if (seg->size + size > seg->alloc)
 225     {
 226       while (seg->size + size > seg->alloc)
 227         seg->alloc *= 2;
 228       seg->data = xrealloc (seg->data, seg->alloc);
 229     }
 230
 231   memset (seg->data + seg->size, 0, size);
 232   seg->size += size;
 233 }
 234
 235
 236 /* Define the given name as the current offset in the given segment.  It
 237    is an error if the name is already defined.  Return 0 or 1 indicating
 238    failure or success respectively. */
 239 static int
 240 seg_defsym (seg, name)
 241      struct bc_seg *seg;
 242      char *name;
 243 {
 244   struct bc_sym *sym;
 245   struct bc_segsym *segsym;
 246
 247   sym = sym_lookup (name);
 248   if (sym->defined)
 249     return 0;
 250
 251   sym->defined = 1;
 252   sym->val = seg->size;
 253   segsym = (struct bc_segsym *) xmalloc (sizeof (struct bc_segsym));
 254   segsym->sym = sym;
 255   segsym->next = seg->syms;
 256   seg->syms = segsym;
 257   return 1;
 258 }
 259
 260
 261 /* Generate in seg's data a reference to the given sym, adjusted by
 262    the given offset. */
 263 static void
 264 seg_refsym (seg, name, offset)
 265      struct bc_seg *seg;
 266      char *name;
 267      int offset;
 268 {
 269   struct bc_sym *sym;
 270   struct bc_segreloc *segreloc;
 271
 272   sym = sym_lookup (name);
 273   segreloc = (struct bc_segreloc *) xmalloc (sizeof (struct bc_segreloc));
 274   segreloc->offset = seg->size;
 275   segreloc->sym = sym;
 276   segreloc->next = seg->relocs;
 277   seg->relocs = segreloc;
 278   seg_data (seg, (char *) &offset, sizeof offset);
 279 }
 280
 281
 282 /* Concatenate the contents of given segments into the first argument. */
 283 static void
 284 seg_concat (result, seg)
 285      struct bc_seg *result, *seg;
 286 {
 287   unsigned int fix;
 288   struct bc_segsym *segsym;
 289   struct bc_segreloc *segreloc;
 290
 291   seg_align (result, MACHINE_SEG_ALIGN);
 292   fix = result->size;
 293   seg_data (result, seg->data, seg->size);
 294   free (seg->data);
 295
 296   /* Go through the symbols and relocs of SEG, adjusting their offsets
 297      for their new location in RESULT. */
 298   if (seg->syms)
 299     {
 300       segsym = seg->syms;
 301       do
 302         segsym->sym->val += fix;
 303       while (segsym->next && (segsym = segsym->next));
 304       segsym->next = result->syms;
 305       result->syms = seg->syms;
 306     }
 307   if (seg->relocs)
 308     {
 309       segreloc = seg->relocs;
 310       do
 311         segreloc->offset += fix;
 312       while (segreloc->next && (segreloc = segreloc->next));
 313       segreloc->next = result->relocs;
 314       result->relocs = seg->relocs;
 315     }
 316
 317   free ((char *) seg);
 318 }
 319
 320 /* Write a segment to a file.  */
 321 static void
 322 bc_seg_write (seg, file)
 323      struct bc_seg *seg;
 324      FILE *file;
 325 {
 326   struct bc_segsym *segsym, *nsegsym, *psegsym;
 327   struct bc_segreloc *segreloc, *nsegreloc, *psegreloc;
 328   int i, offset, flag;
 329
 330   /* Reverse the list of symbols.  */
 331   for (psegsym = 0, segsym = seg->syms; segsym; segsym = nsegsym)
 332     {
 333       nsegsym = segsym->next;
 334       segsym->next = psegsym;
 335       psegsym = segsym;
 336     }
 337   seg->syms = psegsym;
 338
 339   /* Reverse the list of relocs.  */
 340   for (psegreloc = 0, segreloc = seg->relocs; segreloc; segreloc = nsegreloc)
 341     {
 342       nsegreloc = segreloc->next;
 343       segreloc->next = psegreloc;
 344       psegreloc = segreloc;
 345     }
 346   seg->relocs = psegreloc;
 347
 348   /* Output each byte of the segment.  */
 349   for (i = 0, segsym = seg->syms, segreloc = seg->relocs; i < seg->size; ++i)
 350     {
 351       while (segsym && segsym->sym->val == i)
 352         {
 353           if (i % 8 != 0)
 354             putc ('\n', file);
 355
 356           BC_WRITE_SEGSYM (segsym, file);
 357           segsym = segsym->next;
 358           flag = 1;
 359         }
 360       if (segreloc && segreloc->offset == i)
 361         {
 362           if (i % 8 != 0)
 363             putc ('\n', file);
 364
 365           bcopy (seg->data + i, (char *) &offset, sizeof (int));
 366           i += sizeof (int) - 1;
 367
 368           BC_WRITE_RELOC_ENTRY (segreloc, file, offset);
 369           segreloc = segreloc->next;
 370           flag = 1;
 371         }
 372       else
 373         {
 374           if (i % 8 == 0 || flag)
 375             BC_START_BYTECODE_LINE (file);
 376
 377           BC_WRITE_BYTECODE (i % 8 == 0 || flag ? ' ' : ',',
 378                              seg->data[i] & 0xFF,
 379                              file);
 380           flag = 0;
 381           if (i % 8 == 7)
 382             putc ('\n', file);
 383         }
 384     }
 385
 386   /* Paranoia check--we should have visited all syms and relocs during
 387      the output pass.  */
 388
 389   if (segsym || segreloc)
 390     abort ();
 391 }
 392
 393 \f
 394
 395 /* Text and data segments of the object file in making. */
 396 static struct bc_seg *bc_text_seg;
 397 static struct bc_seg *bc_data_seg;
 398
 399 /* Called before anything else in this module. */
 400 void
 401 bc_initialize ()
 402 {
 403   int min_class_size[(int) MAX_MODE_CLASS];
 404   enum machine_mode mode;
 405   int i;
 406
 407   bc_init_mode_to_code_map ();
 408
 409   bc_text_seg = seg_create ();
 410   bc_data_seg = seg_create ();
 411
 412   dconst0 = REAL_VALUE_ATOF ("0", DFmode);
 413   dconst1 = REAL_VALUE_ATOF ("1", DFmode);
 414   dconst2 = REAL_VALUE_ATOF ("2", DFmode);
 415   dconstm1 = REAL_VALUE_ATOF ("-1", DFmode);
 416
 417   /* Find the narrowest mode for each class and compute the word and byte
 418      modes.  */
 419
 420   for (i = 0; i < (int) MAX_MODE_CLASS; i++)
 421     min_class_size[i] = 1000;
 422
 423   for (mode = VOIDmode; (int) mode < (int) MAX_MACHINE_MODE;
 424        mode = (enum machine_mode) ((int) mode + 1))
 425     {
 426       if (GET_MODE_SIZE (mode) < min_class_size[(int) GET_MODE_CLASS (mode)])
 427         {
 428           class_narrowest_mode[(int) GET_MODE_CLASS (mode)] = mode;
 429           min_class_size[(int) GET_MODE_CLASS (mode)] = GET_MODE_SIZE (mode);
 430         }
 431       if (GET_MODE_CLASS (mode) == MODE_INT
 432           && GET_MODE_BITSIZE (mode) == BITS_PER_UNIT)
 433         byte_mode = mode;
 434
 435       if (GET_MODE_CLASS (mode) == MODE_INT
 436           && GET_MODE_BITSIZE (mode) == BITS_PER_WORD)
 437         word_mode = mode;
 438     }
 439 }
 440
 441
 442 /* External addresses referenced in a function.  Rather than trying to
 443    work relocatable address directly into bytecoded functions (which would
 444    require us to provide hairy location info and possibly obey alignment
 445    rules imposed by the architecture) we build an auxiliary table of
 446    pointer constants, and encode just offsets into this table into the
 447    actual bytecode. */
 448 static struct bc_seg *ptrconsts;
 449
 450 /* Trampoline code for the function entry.  */
 451 struct bc_seg *trampoline;
 452
 453 /* Actual byte code of the function. */
 454 struct bc_seg *bytecode;
 455
 456 /* List of labels defined in the function. */
 457 struct bc_label *labels;
 458
 459 /* List of label references in the function. */
 460 struct bc_labelref *labelrefs;
 461
 462
 463 /* Add symbol to pointer table.  Return offset into table where
 464    pointer was stored.  The offset usually goes into the bytecode
 465    stream as a constP literal. */
 466 int
 467 bc_define_pointer (p)
 468      char *p;
 469 {
 470   int offset = ptrconsts->size;
 471
 472   seg_refsym (ptrconsts, p, 0);
 473   return offset;
 474 }
 475
 476
 477 /* Begin a bytecoded function.  */
 478 int
 479 bc_begin_function (name)
 480     char *name;
 481 {
 482   ptrconsts = seg_create ();
 483   trampoline = seg_create ();
 484   bytecode = seg_create ();
 485   return seg_defsym (trampoline, name);
 486 }
 487
 488
 489 /* Force alignment in inline bytecode.  */
 490 void
 491 bc_align_bytecode (align)
 492     int align;
 493 {
 494   seg_align (bytecode, align);
 495 }
 496
 497
 498 /* Emit data inline into bytecode.  */
 499 void
 500 bc_emit_bytecode_const (data, size)
 501      char *data;
 502      unsigned int size;
 503 {
 504   if (bytecode)
 505     seg_data (bytecode, data, size);
 506 }
 507
 508
 509 /* Create a new "bytecode label", to have its value defined later.
 510    Bytecode labels have nothing to do with the object file symbol table,
 511    and are purely local to a given bytecoded function. */
 512 struct bc_label *
 513 bc_get_bytecode_label ()
 514 {
 515   struct bc_label *result;
 516
 517   result = (struct bc_label *) xmalloc (sizeof (struct bc_label));
 518   result->defined = 0;
 519   result->next = labels;
 520   result->uid = 0;
 521   labels = result;
 522   return result;
 523 }
 524
 525
 526 /* Define the given label with the current location counter. */
 527 int
 528 bc_emit_bytecode_labeldef (label)
 529      struct bc_label *label;
 530 {
 531   extern int bc_new_uid ();
 532
 533   if (!label || label->defined)
 534     return 0;
 535
 536   label->offset = bytecode->size;
 537   label->defined = 1;
 538   label->uid = bc_new_uid ();
 539
 540 #ifdef DEBUG_PRINT_CODE
 541   fprintf (stderr, "$%lx:\n", label);
 542 #endif
 543
 544   return 1;
 545 }
 546
 547
 548 /* Generate a location-relative reference to the given bytecode label.
 549    It need not be defined yet; label references will be backpatched later. */
 550 void
 551 bc_emit_bytecode_labelref (label)
 552      struct bc_label *label;
 553 {
 554   struct bc_labelref *labelref;
 555   static int zero;
 556
 557   labelref = (struct bc_labelref *) xmalloc (sizeof (struct bc_labelref));
 558   labelref->label = label;
 559   labelref->offset = bytecode->size;
 560   labelref->next = labelrefs;
 561   labelrefs = labelref;
 562
 563 #ifdef DEBUG_PRINT_CODE
 564   fprintf (stderr, " $%lx", label);
 565 #endif
 566
 567   seg_data (bytecode, (char *) &zero, sizeof zero);
 568 }
 569
 570
 571 /* Emit a reference to an external address; generate the reference in the
 572    ptrconst area, and emit an offset in the bytecode. */
 573 void
 574 bc_emit_code_labelref (name, offset)
 575      char *name;
 576      int offset;
 577 {
 578   int ptroff;
 579
 580   ptroff = ptrconsts->size / sizeof (char *);
 581   seg_data (bytecode, (char *) &ptroff, sizeof ptroff);
 582   seg_refsym (ptrconsts, name, offset);
 583
 584 #ifdef DEBUG_PRINT_CODE
 585   fprintf (stderr, " [external <%x> %s]", ptroff, name);
 586 #endif
 587 }
 588
 589
 590 /* Backpatch label references in the byte code, and concatenate the bytecode
 591    and pointer constant segments to the cumulative text for the object file.
 592    Return a label name for the pointer constants region.  */
 593 char *
 594 bc_end_function ()
 595 {
 596   int addr;
 597   struct bc_label *label, *next;
 598   struct bc_labelref *ref, *nextref;
 599   char ptrconsts_label[20];
 600   static int nlab;
 601
 602   /* Backpatch bytecode label references. */
 603   for (ref = labelrefs; ref; ref = ref->next)
 604     if (ref->label->defined)
 605       {
 606         addr = ref->label->offset;
 607         bcopy ((char *) &addr, bytecode->data + ref->offset, sizeof addr);
 608       }
 609
 610   /* Free the chains of labelrefs and labeldefs. */
 611   for (ref = labelrefs; ref; ref = nextref)
 612     {
 613       nextref = ref->next;
 614       free ((char *) ref);
 615     }
 616
 617   for (label = labels; label; label = next)
 618     {
 619       next = label->next;
 620       free ((char *) label);
 621     }
 622
 623   seg_concat (trampoline, bytecode);
 624   seg_align (trampoline, MACHINE_SEG_ALIGN);
 625   sprintf (ptrconsts_label, "*LP%d", nlab++);
 626   seg_defsym (trampoline, ptrconsts_label);
 627   seg_concat (trampoline, ptrconsts);
 628   seg_concat (bc_text_seg, trampoline);
 629
 630   labels = 0;
 631   labelrefs = 0;
 632   trampoline = 0;
 633   bytecode = 0;
 634   ptrconsts = 0;
 635
 636   return sym_lookup (ptrconsts_label)->name;
 637 }
 638
 639 /* Force alignment in const data. */
 640 void
 641 bc_align_const (align)
 642      int align;
 643 {
 644   seg_align (bc_text_seg, align);
 645 }
 646
 647 /* Emit const data. */
 648 void
 649 bc_emit_const (data, size)
 650      char *data;
 651      unsigned int size;
 652 {
 653   seg_data (bc_text_seg, data, size);
 654 }
 655
 656 /* Emit a zero-filled constant skip. */
 657 void
 658 bc_emit_const_skip (size)
 659      unsigned int size;
 660 {
 661   seg_skip (bc_text_seg, size);
 662 }
 663
 664 /* Emit a label definition in const data. */
 665 int
 666 bc_emit_const_labeldef (name)
 667      char *name;
 668 {
 669   return seg_defsym (bc_text_seg, name);
 670 }
 671
 672 /* Emit a label reference in const data. */
 673 void
 674 bc_emit_const_labelref (name, offset)
 675      char *name;
 676      int offset;
 677 {
 678   seg_refsym (bc_text_seg, name, offset);
 679 }
 680
 681 /* Force alignment in data. */
 682 void
 683 bc_align_data (align)
 684      int align;
 685 {
 686   seg_align (bc_data_seg, align);
 687 }
 688
 689 /* Emit data. */
 690 void
 691 bc_emit_data (data, size)
 692      char *data;
 693      unsigned int size;
 694 {
 695   seg_data (bc_data_seg, data, size);
 696 }
 697
 698 /* Emit a zero-filled data skip.  */
 699 void
 700 bc_emit_data_skip (size)
 701      unsigned int size;
 702 {
 703   seg_skip (bc_data_seg, size);
 704 }
 705
 706 /* Emit label definition in data. */
 707 int
 708 bc_emit_data_labeldef (name)
 709      char *name;
 710 {
 711   return seg_defsym (bc_data_seg, name);
 712 }
 713
 714 /* Emit label reference in data. */
 715 void
 716 bc_emit_data_labelref (name, offset)
 717      char *name;
 718      int offset;
 719 {
 720   seg_refsym (bc_data_seg, name, offset);
 721 }
 722
 723 /* Emit a common block of the given name and size.  Note that
 724    when the .o file is actually written non-global "common"
 725    blocks will have to be turned into space in the data section.  */
 726 int
 727 bc_emit_common (name, size)
 728      char *name;
 729      unsigned int size;
 730 {
 731   struct bc_sym *sym;
 732
 733   sym = sym_lookup (name);
 734   if (sym->defined)
 735     return 0;
 736
 737   sym->defined = 1;
 738   sym->common = 1;
 739   sym->val = size;
 740   return 1;
 741 }
 742
 743 /* Globalize the given label. */
 744 void
 745 bc_globalize_label (name)
 746      char *name;
 747 {
 748   struct bc_sym *sym;
 749
 750   sym = sym_lookup (name);
 751   sym->global = 1;
 752 }
 753
 754 static enum { in_text, in_data } section = in_text;
 755
 756 void
 757 bc_text ()
 758 {
 759   section = in_text;
 760 }
 761
 762 void
 763 bc_data ()
 764 {
 765   section = in_data;
 766 }
 767
 768 void
 769 bc_align (align)
 770      int align;
 771 {
 772   if (section == in_text)
 773     bc_align_const (align);
 774   else
 775     bc_align_data (align);
 776 }
 777
 778 void
 779 bc_emit (data, size)
 780      char *data;
 781      unsigned int size;
 782 {
 783   if (section == in_text)
 784     bc_emit_const (data, size);
 785   else
 786     bc_emit_data (data, size);
 787 }
 788
 789 void
 790 bc_emit_skip (size)
 791      unsigned int size;
 792 {
 793   if (section == in_text)
 794     bc_emit_const_skip (size);
 795   else
 796     bc_emit_data_skip (size);
 797 }
 798
 799 int
 800 bc_emit_labeldef (name)
 801      char *name;
 802 {
 803   if (section == in_text)
 804     return bc_emit_const_labeldef (name);
 805   else
 806     return bc_emit_data_labeldef (name);
 807 }
 808
 809 void
 810 bc_emit_labelref (name, offset)
 811      char *name;
 812      int offset;
 813 {
 814   if (section == in_text)
 815     bc_emit_const_labelref (name, offset);
 816   else
 817     bc_emit_data_labelref (name, offset);
 818 }
 819
 820 void
 821 bc_write_file (file)
 822      FILE *file;
 823 {
 824   BC_WRITE_FILE (file);
 825 }
 826
 827
 828 /* Allocate a new bytecode rtx.
 829    If you supply a null BC_LABEL, we generate one.  */
 830
 831 rtx
 832 bc_gen_rtx (label, offset, bc_label)
 833      char *label;
 834      int offset;
 835      struct bc_label *bc_label;
 836 {
 837   rtx r;
 838
 839   if (bc_label == 0)
 840     bc_label = (struct bc_label *) xmalloc (sizeof (struct bc_label));
 841
 842   r = gen_rtx (CODE_LABEL, VOIDmode, label, bc_label);
 843   bc_label->offset = offset;
 844
 845   return r;
 846 }
 847
 848
 849 /* Print bytecode rtx */
 850 void
 851 bc_print_rtl (fp, r)
 852      FILE *fp;
 853      rtx r;
 854 {
 855 #if 0 /* This needs to get fixed to really work again.  */
 856   /* BC_WRITE_RTL has a definition
 857      that doesn't even make sense for this use.  */
 858   BC_WRITE_RTL (r, fp);
 859 #endif
 860 }
 861
 862
 863 /* Emit a bytecode, keeping a running tally of the stack depth.  */
 864 void
 865 bc_emit_bytecode (bytecode)
 866      enum bytecode_opcode bytecode;
 867 {
 868   char byte;
 869   static int prev_lineno = -1;
 870
 871   byte = (char) bytecode;
 872
 873 #ifdef BCDEBUG_PRINT_CODE
 874   if (lineno != prev_lineno)
 875     {
 876       fprintf (stderr, "<line %d>\n", lineno);
 877       prev_lineno = lineno;
 878     }
 879
 880   fputs (opcode_name[(unsigned int) bytecode], stderr);
 881 #endif
 882
 883   /* Due to errors we are often requested to output bytecodes that
 884      will cause an interpreter stack undeflow when executed.  Instead of
 885      dumping core on such occasions, we omit the bytecode.  Erroneous code
 886      should not be executed, regardless.  This makes life much easier, since
 887      we don't have to deceive ourselves about the known stack depth. */
 888
 889   bc_emit_bytecode_const (&byte, 1);
 890
 891   if ((stack_depth -= arityvec[(int) bytecode].ninputs) >= 0)
 892     {
 893       if ((stack_depth += arityvec[(int) bytecode].noutputs) > max_stack_depth)
 894         max_stack_depth = stack_depth;
 895     }
 896
 897 #ifdef VALIDATE_STACK_FOR_BC
 898   VALIDATE_STACK_FOR_BC ();
 899 #endif
 900 }
 901
 902
 903 #ifdef BCDEBUG_PRINT_CODE
 904 #define PRLIT(TYPE, PTR)  fprintf (stderr, " [%x]", *(TYPE *) PTR)
 905 #else
 906 #define PRLIT(X,Y)
 907 #endif
 908
 909 /* Emit a complete bytecode instruction, expecting the correct number
 910    of literal values in the call.  First argument is the instruction, the
 911    remaining arguments are literals of size HOST_WIDE_INT or smaller. */
 912 void
 913 bc_emit_instruction VPROTO((enum bytecode_opcode opcode, ...))
 914 {
 915 #ifndef __STDC__
 916   enum bytecode_opcode opcode;
 917 #endif
 918   va_list arguments;
 919   int nliteral, instruction;
 920
 921   VA_START (arguments, opcode);
 922
 923 #ifndef __STDC__
 924   opcode = va_arg (arguments, enum bytecode_opcode);
 925 #endif
 926
 927   /* Emit instruction bytecode */
 928   bc_emit_bytecode (opcode);
 929   instruction = (int) opcode;
 930
 931   /* Loop literals and emit as bytecode constants */
 932   for (nliteral = 0; nliteral < arityvec[instruction].nliterals; nliteral++)
 933     {
 934       switch (arityvec[instruction].literals[nliteral])
 935         {
 936 /* This conditional is a kludge, but it's necessary
 937    because TYPE might be long long.  */
 938 #ifdef __GNUC__
 939           /* Expand definitions into case statements */
 940 #define DEFTYPECODE(CODE, NAME, MODE, TYPE)                             \
 941         case CODE:                                                      \
 942           {                                                             \
 943             TYPE temp = va_arg (arguments, TYPE);                       \
 944             bc_emit_bytecode_const ((void *) &temp, sizeof temp);       \
 945             PRLIT (TYPE, &temp); }                                      \
 946           break;
 947
 948 #include "bc-typecd.def"
 949
 950 #undef DEFTYPECODE
 951 #endif /* __GNUC__ */
 952
 953         default:
 954           abort ();
 955         }
 956     }
 957
 958 #ifdef BCDEBUG_PRINT_CODE
 959   fputc ('\n', stderr);
 960 #endif
 961 }
 962 \f
 963 /* Emit the machine-code interface trampoline at the beginning of a byte
 964    coded function.  The argument is a label name of the interpreter
 965    bytecode callinfo structure; the return value is a label name for
 966    the beginning of the actual bytecode.  */
 967 char *
 968 bc_emit_trampoline (callinfo)
 969      char *callinfo;
 970 {
 971   char mylab[20];
 972   static int n;
 973
 974   sprintf (mylab, "*LB%d", n++);
 975
 976   BC_EMIT_TRAMPOLINE (trampoline, callinfo);
 977
 978   seg_defsym (bytecode, mylab);
 979   return sym_lookup (mylab)->name;
 980 }
 981
 982
 983 /* Simple strdup */
 984 char *
 985 bc_xstrdup (str)
 986      char *str;
 987 {
 988   char *tmp = xmalloc (strlen (str) + 1);
 989
 990   strcpy (tmp, str);
 991   return tmp;
 992 }