gas/cgen.c

   1 /* GAS interface for targets using CGEN: Cpu tools GENerator.
   2    Copyright 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
   3    Free Software Foundation, Inc.
   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 Software
  19    Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #include <setjmp.h>
  22 #include "ansidecl.h"
  23 #include "libiberty.h"
  24 #include "bfd.h"
  25 #include "symcat.h"
  26 #include "cgen-desc.h"
  27 #include "as.h"
  28 #include "subsegs.h"
  29 #include "cgen.h"
  30 #include "dwarf2dbg.h"
  31
  32 static void queue_fixup PARAMS ((int, int, expressionS *));
  33
  34 /* Opcode table descriptor, must be set by md_begin.  */
  35
  36 CGEN_CPU_DESC gas_cgen_cpu_desc;
  37
  38 /* Callback to insert a register into the symbol table.
  39    A target may choose to let GAS parse the registers.
  40    ??? Not currently used.  */
  41
  42 void
  43 cgen_asm_record_register (name, number)
  44      char *name;
  45      int number;
  46 {
  47   /* Use symbol_create here instead of symbol_new so we don't try to
  48      output registers into the object file's symbol table.  */
  49   symbol_table_insert (symbol_create (name, reg_section,
  50                                       number, &zero_address_frag));
  51 }
  52
  53 /* We need to keep a list of fixups.  We can't simply generate them as
  54    we go, because that would require us to first create the frag, and
  55    that would screw up references to ``.''.
  56
  57    This is used by cpu's with simple operands.  It keeps knowledge of what
  58    an `expressionS' is and what a `fixup' is out of CGEN which for the time
  59    being is preferable.
  60
  61    OPINDEX is the index in the operand table.
  62    OPINFO is something the caller chooses to help in reloc determination.  */
  63
  64 struct fixup
  65 {
  66   int opindex;
  67   int opinfo;
  68   expressionS exp;
  69 };
  70
  71 static struct fixup fixups[GAS_CGEN_MAX_FIXUPS];
  72 static int num_fixups;
  73
  74 /* Prepare to parse an instruction.
  75    ??? May wish to make this static and delete calls in md_assemble.  */
  76
  77 void
  78 gas_cgen_init_parse ()
  79 {
  80   num_fixups = 0;
  81 }
  82
  83 /* Queue a fixup.  */
  84
  85 static void
  86 queue_fixup (opindex, opinfo, expP)
  87      int           opindex;
  88      int           opinfo;
  89      expressionS * expP;
  90 {
  91   /* We need to generate a fixup for this expression.  */
  92   if (num_fixups >= GAS_CGEN_MAX_FIXUPS)
  93     as_fatal (_("too many fixups"));
  94   fixups[num_fixups].exp     = *expP;
  95   fixups[num_fixups].opindex = opindex;
  96   fixups[num_fixups].opinfo  = opinfo;
  97   ++ num_fixups;
  98 }
  99
 100 /* The following functions allow fixup chains to be stored, retrieved,
 101    and swapped.  They are a generalization of a pre-existing scheme
 102    for storing, restoring and swapping fixup chains that was used by
 103    the m32r port.  The functionality is essentially the same, only
 104    instead of only being able to store a single fixup chain, an entire
 105    array of fixup chains can be stored.  It is the user's responsibility
 106    to keep track of how many fixup chains have been stored and which
 107    elements of the array they are in.
 108
 109    The algorithms used are the same as in the old scheme.  Other than the
 110    "array-ness" of the whole thing, the functionality is identical to the
 111    old scheme.
 112
 113    gas_cgen_initialize_saved_fixups_array():
 114       Sets num_fixups_in_chain to 0 for each element. Call this from
 115       md_begin() if you plan to use these functions and you want the
 116       fixup count in each element to be set to 0 initially.  This is
 117       not necessary, but it's included just in case.  It performs
 118       the same function for each element in the array of fixup chains
 119       that gas_init_parse() performs for the current fixups.
 120
 121    gas_cgen_save_fixups (element):
 122       element - element number of the array you wish to store the fixups
 123                 to.  No mechanism is built in for tracking what element
 124                 was last stored to.
 125
 126    gas_cgen_restore_fixups (element):
 127       element - element number of the array you wish to restore the fixups
 128                 from.
 129
 130    gas_cgen_swap_fixups(int element):
 131        element - swap the current fixups with those in this element number.
 132 */
 133
 134 struct saved_fixups
 135 {
 136   struct fixup fixup_chain[GAS_CGEN_MAX_FIXUPS];
 137   int num_fixups_in_chain;
 138 };
 139
 140 static struct saved_fixups stored_fixups[MAX_SAVED_FIXUP_CHAINS];
 141
 142 void
 143 gas_cgen_initialize_saved_fixups_array ()
 144 {
 145   int i = 0;
 146
 147   while (i < MAX_SAVED_FIXUP_CHAINS)
 148     stored_fixups[i++].num_fixups_in_chain = 0;
 149 }
 150
 151 void
 152 gas_cgen_save_fixups (i)
 153      int i;
 154 {
 155   if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
 156     {
 157       as_fatal ("index into stored_fixups[] out of bounds");
 158       return;
 159     }
 160
 161   stored_fixups[i].num_fixups_in_chain = num_fixups;
 162   memcpy (stored_fixups[i].fixup_chain, fixups,
 163           sizeof (fixups[0]) * num_fixups);
 164   num_fixups = 0;
 165 }
 166
 167 void
 168 gas_cgen_restore_fixups (i)
 169      int i;
 170 {
 171   if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
 172     {
 173       as_fatal ("index into stored_fixups[] out of bounds");
 174       return;
 175     }
 176
 177   num_fixups = stored_fixups[i].num_fixups_in_chain;
 178   memcpy (fixups, stored_fixups[i].fixup_chain,
 179           (sizeof (stored_fixups[i].fixup_chain[0])) * num_fixups);
 180   stored_fixups[i].num_fixups_in_chain = 0;
 181 }
 182
 183 void
 184 gas_cgen_swap_fixups (i)
 185      int i;
 186 {
 187   if (i < 0 || i >= MAX_SAVED_FIXUP_CHAINS)
 188     {
 189       as_fatal ("index into stored_fixups[] out of bounds");
 190       return;
 191     }
 192
 193   if (num_fixups == 0)
 194     gas_cgen_restore_fixups (i);
 195
 196   else if (stored_fixups[i].num_fixups_in_chain == 0)
 197     gas_cgen_save_fixups (i);
 198
 199   else
 200     {
 201       int tmp;
 202       struct fixup tmp_fixup;
 203
 204       tmp = stored_fixups[i].num_fixups_in_chain;
 205       stored_fixups[i].num_fixups_in_chain = num_fixups;
 206       num_fixups = tmp;
 207
 208       for (tmp = GAS_CGEN_MAX_FIXUPS; tmp--;)
 209         {
 210           tmp_fixup = stored_fixups[i].fixup_chain [tmp];
 211           stored_fixups[i].fixup_chain[tmp] = fixups [tmp];
 212           fixups [tmp] = tmp_fixup;
 213         }
 214     }
 215 }
 216
 217 /* Default routine to record a fixup.
 218    This is a cover function to fix_new.
 219    It exists because we record INSN with the fixup.
 220
 221    FRAG and WHERE are their respective arguments to fix_new_exp.
 222    LENGTH is in bits.
 223    OPINFO is something the caller chooses to help in reloc determination.
 224
 225    At this point we do not use a bfd_reloc_code_real_type for
 226    operands residing in the insn, but instead just use the
 227    operand index.  This lets us easily handle fixups for any
 228    operand type.  We pick a BFD reloc type in md_apply_fix3.  */
 229
 230 fixS *
 231 gas_cgen_record_fixup (frag, where, insn, length, operand, opinfo, symbol, offset)
 232      fragS *              frag;
 233      int                  where;
 234      const CGEN_INSN *    insn;
 235      int                  length;
 236      const CGEN_OPERAND * operand;
 237      int                  opinfo;
 238      symbolS *            symbol;
 239      offsetT              offset;
 240 {
 241   fixS *fixP;
 242
 243   /* It may seem strange to use operand->attrs and not insn->attrs here,
 244      but it is the operand that has a pc relative relocation.  */
 245   fixP = fix_new (frag, where, length / 8, symbol, offset,
 246                   CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
 247                   (bfd_reloc_code_real_type)
 248                     ((int) BFD_RELOC_UNUSED
 249                      + (int) operand->type));
 250   fixP->fx_cgen.insn = insn;
 251   fixP->fx_cgen.opinfo = opinfo;
 252
 253   return fixP;
 254 }
 255
 256 /* Default routine to record a fixup given an expression.
 257    This is a cover function to fix_new_exp.
 258    It exists because we record INSN with the fixup.
 259
 260    FRAG and WHERE are their respective arguments to fix_new_exp.
 261    LENGTH is in bits.
 262    OPINFO is something the caller chooses to help in reloc determination.
 263
 264    At this point we do not use a bfd_reloc_code_real_type for
 265    operands residing in the insn, but instead just use the
 266    operand index.  This lets us easily handle fixups for any
 267    operand type.  We pick a BFD reloc type in md_apply_fix3.  */
 268
 269 fixS *
 270 gas_cgen_record_fixup_exp (frag, where, insn, length, operand, opinfo, exp)
 271      fragS *              frag;
 272      int                  where;
 273      const CGEN_INSN *    insn;
 274      int                  length;
 275      const CGEN_OPERAND * operand;
 276      int                  opinfo;
 277      expressionS *        exp;
 278 {
 279   fixS *fixP;
 280
 281   /* It may seem strange to use operand->attrs and not insn->attrs here,
 282      but it is the operand that has a pc relative relocation.  */
 283   fixP = fix_new_exp (frag, where, length / 8, exp,
 284                       CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_PCREL_ADDR),
 285                       (bfd_reloc_code_real_type)
 286                         ((int) BFD_RELOC_UNUSED
 287                          + (int) operand->type));
 288   fixP->fx_cgen.insn = insn;
 289   fixP->fx_cgen.opinfo = opinfo;
 290
 291   return fixP;
 292 }
 293
 294 /* Used for communication between the next two procedures.  */
 295 static jmp_buf expr_jmp_buf;
 296 static int expr_jmp_buf_p;
 297
 298 /* Callback for cgen interface.  Parse the expression at *STRP.
 299    The result is an error message or NULL for success (in which case
 300    *STRP is advanced past the parsed text).
 301    WANT is an indication of what the caller is looking for.
 302    If WANT == CGEN_ASM_PARSE_INIT the caller is beginning to try to match
 303    a table entry with the insn, reset the queued fixups counter.
 304    An enum cgen_parse_operand_result is stored in RESULTP.
 305    OPINDEX is the operand's table entry index.
 306    OPINFO is something the caller chooses to help in reloc determination.
 307    The resulting value is stored in VALUEP.  */
 308
 309 const char *
 310 gas_cgen_parse_operand (cd, want, strP, opindex, opinfo, resultP, valueP)
 311      CGEN_CPU_DESC cd ATTRIBUTE_UNUSED;
 312      enum cgen_parse_operand_type want;
 313      const char **strP;
 314      int opindex;
 315      int opinfo;
 316      enum cgen_parse_operand_result *resultP;
 317      bfd_vma *valueP;
 318 {
 319 #ifdef __STDC__
 320   /* These are volatile to survive the setjmp.  */
 321   char * volatile hold;
 322   enum cgen_parse_operand_result * volatile resultP_1;
 323 #else
 324   static char *hold;
 325   static enum cgen_parse_operand_result *resultP_1;
 326 #endif
 327   const char *errmsg;
 328   expressionS exp;
 329
 330   if (want == CGEN_PARSE_OPERAND_INIT)
 331     {
 332       gas_cgen_init_parse ();
 333       return NULL;
 334     }
 335
 336   resultP_1 = resultP;
 337   hold = input_line_pointer;
 338   input_line_pointer = (char *) *strP;
 339
 340   /* We rely on md_operand to longjmp back to us.
 341      This is done via gas_cgen_md_operand.  */
 342   if (setjmp (expr_jmp_buf) != 0)
 343     {
 344       expr_jmp_buf_p = 0;
 345       input_line_pointer = (char *) hold;
 346       *resultP_1 = CGEN_PARSE_OPERAND_RESULT_ERROR;
 347       return _("illegal operand");
 348     }
 349
 350   expr_jmp_buf_p = 1;
 351   expression (&exp);
 352   expr_jmp_buf_p = 0;
 353   errmsg = NULL;
 354
 355   *strP = input_line_pointer;
 356   input_line_pointer = hold;
 357
 358   /* FIXME: Need to check `want'.  */
 359
 360   switch (exp.X_op)
 361     {
 362     case O_illegal:
 363       errmsg = _("illegal operand");
 364       *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
 365       break;
 366     case O_absent:
 367       errmsg = _("missing operand");
 368       *resultP = CGEN_PARSE_OPERAND_RESULT_ERROR;
 369       break;
 370     case O_constant:
 371       *valueP = exp.X_add_number;
 372       *resultP = CGEN_PARSE_OPERAND_RESULT_NUMBER;
 373       break;
 374     case O_register:
 375       *valueP = exp.X_add_number;
 376       *resultP = CGEN_PARSE_OPERAND_RESULT_REGISTER;
 377       break;
 378     default:
 379       queue_fixup (opindex, opinfo, &exp);
 380       *valueP = 0;
 381       *resultP = CGEN_PARSE_OPERAND_RESULT_QUEUED;
 382       break;
 383     }
 384
 385   return errmsg;
 386 }
 387
 388 /* md_operand handler to catch unrecognized expressions and halt the
 389    parsing process so the next entry can be tried.
 390
 391    ??? This could be done differently by adding code to `expression'.  */
 392
 393 void
 394 gas_cgen_md_operand (expressionP)
 395      expressionS *expressionP ATTRIBUTE_UNUSED;
 396 {
 397   /* Don't longjmp if we're not called from within cgen_parse_operand().  */
 398   if (expr_jmp_buf_p)
 399     longjmp (expr_jmp_buf, 1);
 400 }
 401
 402 /* Finish assembling instruction INSN.
 403    BUF contains what we've built up so far.
 404    LENGTH is the size of the insn in bits.
 405    RELAX_P is non-zero if relaxable insns should be emitted as such.
 406    Otherwise they're emitted in non-relaxable forms.
 407    The "result" is stored in RESULT if non-NULL.  */
 408
 409 void
 410 gas_cgen_finish_insn (insn, buf, length, relax_p, result)
 411      const CGEN_INSN *insn;
 412      CGEN_INSN_BYTES_PTR buf;
 413      unsigned int length;
 414      int relax_p;
 415      finished_insnS *result;
 416 {
 417   int i;
 418   int relax_operand;
 419   char *f;
 420   unsigned int byte_len = length / 8;
 421
 422   /* ??? Target foo issues various warnings here, so one might want to provide
 423      a hook here.  However, our caller is defined in tc-foo.c so there
 424      shouldn't be a need for a hook.  */
 425
 426   /* Write out the instruction.
 427      It is important to fetch enough space in one call to `frag_more'.
 428      We use (f - frag_now->fr_literal) to compute where we are and we
 429      don't want frag_now to change between calls.
 430
 431      Relaxable instructions: We need to ensure we allocate enough
 432      space for the largest insn.  */
 433
 434   if (CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAX))
 435     /* These currently shouldn't get here.  */
 436     abort ();
 437
 438   /* Is there a relaxable insn with the relaxable operand needing a fixup?  */
 439
 440   relax_operand = -1;
 441   if (relax_p && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE))
 442     {
 443       /* Scan the fixups for the operand affected by relaxing
 444          (i.e. the branch address).  */
 445
 446       for (i = 0; i < num_fixups; ++i)
 447         {
 448           if (CGEN_OPERAND_ATTR_VALUE (cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex),
 449                                        CGEN_OPERAND_RELAX))
 450             {
 451               relax_operand = i;
 452               break;
 453             }
 454         }
 455     }
 456
 457   if (relax_operand != -1)
 458     {
 459       int max_len;
 460       fragS *old_frag;
 461       expressionS *exp;
 462       symbolS *sym;
 463       offsetT off;
 464
 465 #ifdef TC_CGEN_MAX_RELAX
 466       max_len = TC_CGEN_MAX_RELAX (insn, byte_len);
 467 #else
 468       max_len = CGEN_MAX_INSN_SIZE;
 469 #endif
 470       /* Ensure variable part and fixed part are in same fragment.  */
 471       /* FIXME: Having to do this seems like a hack.  */
 472       frag_grow (max_len);
 473
 474       /* Allocate space for the fixed part.  */
 475       f = frag_more (byte_len);
 476
 477       /* Create a relaxable fragment for this instruction.  */
 478       old_frag = frag_now;
 479
 480       exp = &fixups[relax_operand].exp;
 481       sym = exp->X_add_symbol;
 482       off = exp->X_add_number;
 483       if (exp->X_op != O_constant && exp->X_op != O_symbol)
 484         {
 485           /* Handle complex expressions.  */
 486           sym = make_expr_symbol (exp);
 487           off = 0;
 488         }
 489
 490       frag_var (rs_machine_dependent,
 491                 max_len - byte_len /* max chars */,
 492                 0 /* variable part already allocated */,
 493                 /* FIXME: When we machine generate the relax table,
 494                    machine generate a macro to compute subtype.  */
 495                 1 /* subtype */,
 496                 sym,
 497                 off,
 498                 f);
 499
 500       /* Record the operand number with the fragment so md_convert_frag
 501          can use gas_cgen_md_record_fixup to record the appropriate reloc.  */
 502       old_frag->fr_cgen.insn    = insn;
 503       old_frag->fr_cgen.opindex = fixups[relax_operand].opindex;
 504       old_frag->fr_cgen.opinfo  = fixups[relax_operand].opinfo;
 505       if (result)
 506         result->frag = old_frag;
 507     }
 508   else
 509     {
 510       f = frag_more (byte_len);
 511       if (result)
 512         result->frag = frag_now;
 513     }
 514
 515   /* If we're recording insns as numbers (rather than a string of bytes),
 516      target byte order handling is deferred until now.  */
 517 #if CGEN_INT_INSN_P
 518   cgen_put_insn_value (gas_cgen_cpu_desc, f, length, *buf);
 519 #else
 520   memcpy (f, buf, byte_len);
 521 #endif
 522
 523   /* Emit DWARF2 debugging information.  */
 524   dwarf2_emit_insn (byte_len);
 525
 526   /* Create any fixups.  */
 527   for (i = 0; i < num_fixups; ++i)
 528     {
 529       fixS *fixP;
 530       const CGEN_OPERAND *operand =
 531         cgen_operand_lookup_by_num (gas_cgen_cpu_desc, fixups[i].opindex);
 532
 533       /* Don't create fixups for these.  That's done during relaxation.
 534          We don't need to test for CGEN_INSN_RELAX as they can't get here
 535          (see above).  */
 536       if (relax_p
 537           && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXABLE)
 538           && CGEN_OPERAND_ATTR_VALUE (operand, CGEN_OPERAND_RELAX))
 539         continue;
 540
 541 #ifndef md_cgen_record_fixup_exp
 542 #define md_cgen_record_fixup_exp gas_cgen_record_fixup_exp
 543 #endif
 544
 545       fixP = md_cgen_record_fixup_exp (frag_now, f - frag_now->fr_literal,
 546                                        insn, length, operand,
 547                                        fixups[i].opinfo,
 548                                        &fixups[i].exp);
 549       if (result)
 550         result->fixups[i] = fixP;
 551     }
 552
 553   if (result)
 554     {
 555       result->num_fixups = num_fixups;
 556       result->addr = f;
 557     }
 558 }
 559
 560 /* Apply a fixup to the object code.  This is called for all the
 561    fixups we generated by the call to fix_new_exp, above.  In the call
 562    above we used a reloc code which was the largest legal reloc code
 563    plus the operand index.  Here we undo that to recover the operand
 564    index.  At this point all symbol values should be fully resolved,
 565    and we attempt to completely resolve the reloc.  If we can not do
 566    that, we determine the correct reloc code and put it back in the fixup.  */
 567
 568 /* FIXME: This function handles some of the fixups and bfd_install_relocation
 569    handles the rest.  bfd_install_relocation (or some other bfd function)
 570    should handle them all.  */
 571
 572 void
 573 gas_cgen_md_apply_fix3 (fixP, valP, seg)
 574      fixS *   fixP;
 575      valueT * valP;
 576      segT     seg ATTRIBUTE_UNUSED;
 577 {
 578   char *where = fixP->fx_frag->fr_literal + fixP->fx_where;
 579   valueT value = * valP;
 580   /* Canonical name, since used a lot.  */
 581   CGEN_CPU_DESC cd = gas_cgen_cpu_desc;
 582
 583   if (fixP->fx_addsy == (symbolS *) NULL)
 584     fixP->fx_done = 1;
 585
 586   /* We don't actually support subtracting a symbol.  */
 587   if (fixP->fx_subsy != (symbolS *) NULL)
 588     as_bad_where (fixP->fx_file, fixP->fx_line, _("expression too complex"));
 589
 590   if ((int) fixP->fx_r_type >= (int) BFD_RELOC_UNUSED)
 591     {
 592       int opindex = (int) fixP->fx_r_type - (int) BFD_RELOC_UNUSED;
 593       const CGEN_OPERAND *operand = cgen_operand_lookup_by_num (cd, opindex);
 594       const char *errmsg;
 595       bfd_reloc_code_real_type reloc_type;
 596       CGEN_FIELDS *fields = alloca (CGEN_CPU_SIZEOF_FIELDS (cd));
 597       const CGEN_INSN *insn = fixP->fx_cgen.insn;
 598
 599       /* If the reloc has been fully resolved finish the operand here.  */
 600       /* FIXME: This duplicates the capabilities of code in BFD.  */
 601       if (fixP->fx_done
 602           /* FIXME: If partial_inplace isn't set bfd_install_relocation won't
 603              finish the job.  Testing for pcrel is a temporary hack.  */
 604           || fixP->fx_pcrel)
 605         {
 606           CGEN_CPU_SET_FIELDS_BITSIZE (cd) (fields, CGEN_INSN_BITSIZE (insn));
 607           CGEN_CPU_SET_VMA_OPERAND (cd) (cd, opindex, fields, (bfd_vma) value);
 608
 609 #if CGEN_INT_INSN_P
 610           {
 611             CGEN_INSN_INT insn_value =
 612               cgen_get_insn_value (cd, where, CGEN_INSN_BITSIZE (insn));
 613
 614             /* ??? 0 is passed for `pc'.  */
 615             errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields,
 616                                                    &insn_value, (bfd_vma) 0);
 617             cgen_put_insn_value (cd, where, CGEN_INSN_BITSIZE (insn),
 618                                  insn_value);
 619           }
 620 #else
 621           /* ??? 0 is passed for `pc'.  */
 622           errmsg = CGEN_CPU_INSERT_OPERAND (cd) (cd, opindex, fields, where,
 623                                                  (bfd_vma) 0);
 624 #endif
 625           if (errmsg)
 626             as_bad_where (fixP->fx_file, fixP->fx_line, "%s", errmsg);
 627         }
 628
 629       if (fixP->fx_done)
 630         return;
 631
 632       /* The operand isn't fully resolved.  Determine a BFD reloc value
 633          based on the operand information and leave it to
 634          bfd_install_relocation.  Note that this doesn't work when
 635          partial_inplace == false.  */
 636
 637       reloc_type = md_cgen_lookup_reloc (insn, operand, fixP);
 638
 639       if (reloc_type != BFD_RELOC_NONE)
 640         fixP->fx_r_type = reloc_type;
 641       else
 642         {
 643           as_bad_where (fixP->fx_file, fixP->fx_line,
 644                         _("unresolved expression that must be resolved"));
 645           fixP->fx_done = 1;
 646           return;
 647         }
 648     }
 649   else if (fixP->fx_done)
 650     {
 651       /* We're finished with this fixup.  Install it because
 652          bfd_install_relocation won't be called to do it.  */
 653       switch (fixP->fx_r_type)
 654         {
 655         case BFD_RELOC_8:
 656           md_number_to_chars (where, value, 1);
 657           break;
 658         case BFD_RELOC_16:
 659           md_number_to_chars (where, value, 2);
 660           break;
 661         case BFD_RELOC_32:
 662           md_number_to_chars (where, value, 4);
 663           break;
 664         case BFD_RELOC_64:
 665           md_number_to_chars (where, value, 8);
 666           break;
 667         default:
 668           as_bad_where (fixP->fx_file, fixP->fx_line,
 669                         _("internal error: can't install fix for reloc type %d (`%s')"),
 670                         fixP->fx_r_type, bfd_get_reloc_code_name (fixP->fx_r_type));
 671           break;
 672         }
 673     }
 674   /* else
 675      bfd_install_relocation will be called to finish things up.  */
 676
 677   /* Tuck `value' away for use by tc_gen_reloc.
 678      See the comment describing fx_addnumber in write.h.
 679      This field is misnamed (or misused :-).  */
 680   fixP->fx_addnumber = value;
 681 }
 682
 683 /* Translate internal representation of relocation info to BFD target format.
 684
 685    FIXME: To what extent can we get all relevant targets to use this?  */
 686
 687 arelent *
 688 gas_cgen_tc_gen_reloc (section, fixP)
 689      asection * section ATTRIBUTE_UNUSED;
 690      fixS *     fixP;
 691 {
 692   arelent *reloc;
 693
 694   reloc = (arelent *) xmalloc (sizeof (arelent));
 695
 696   reloc->howto = bfd_reloc_type_lookup (stdoutput, fixP->fx_r_type);
 697   if (reloc->howto == (reloc_howto_type *) NULL)
 698     {
 699       as_bad_where (fixP->fx_file, fixP->fx_line,
 700                     _("relocation is not supported"));
 701       return NULL;
 702     }
 703
 704   assert (!fixP->fx_pcrel == !reloc->howto->pc_relative);
 705
 706   reloc->sym_ptr_ptr = (asymbol **) xmalloc (sizeof (asymbol *));
 707   *reloc->sym_ptr_ptr = symbol_get_bfdsym (fixP->fx_addsy);
 708
 709   /* Use fx_offset for these cases.  */
 710   if (fixP->fx_r_type == BFD_RELOC_VTABLE_ENTRY
 711       || fixP->fx_r_type == BFD_RELOC_VTABLE_INHERIT)
 712     reloc->addend = fixP->fx_offset;
 713   else
 714     reloc->addend = fixP->fx_addnumber;
 715
 716   reloc->address = fixP->fx_frag->fr_address + fixP->fx_where;
 717   return reloc;
 718 }
 719
 720 /* Perform any cgen specific initialisation.
 721    Called after gas_cgen_cpu_desc has been created.  */
 722
 723 void
 724 gas_cgen_begin ()
 725 {
 726   if (flag_signed_overflow_ok)
 727     cgen_set_signed_overflow_ok (gas_cgen_cpu_desc);
 728   else
 729     cgen_clear_signed_overflow_ok (gas_cgen_cpu_desc);
 730 }