bfd/reloc.c

   1 /* BFD support for handling relocation entries.
   2    Copyright (C) 1990, 1991, 1992, 1993 Free Software Foundation, Inc.
   3    Written by Cygnus Support.
   4
   5 This file is part of BFD, the Binary File Descriptor library.
   6
   7 This program 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 of the License, or
  10 (at your option) any later version.
  11
  12 This program 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 this program; if not, write to the Free Software
  19 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 /*
  22 SECTION
  23         Relocations
  24
  25         BFD maintains relocations in much the same was as it maintains
  26         symbols; they are left alone until required, then read in
  27         en-mass and traslated into an internal form. There is a common
  28         routine <<bfd_perform_relocation>> which acts upon the
  29         canonical form to to the actual fixup.
  30
  31         Note that relocations are maintained on a per section basis,
  32         whilst symbols are maintained on a per BFD basis.
  33
  34         All a back end has to do to fit the BFD interface is to create
  35         as many <<struct reloc_cache_entry>> as there are relocations
  36         in a particular section, and fill in the right bits:
  37
  38 @menu
  39 @* typedef arelent::
  40 @* howto manager::
  41 @end menu
  42
  43 */
  44 #include "bfd.h"
  45 #include "sysdep.h"
  46 #include "libbfd.h"
  47 #include "seclet.h"
  48 /*
  49 DOCDD
  50 INODE
  51         typedef arelent, howto manager, Relocations, Relocations
  52
  53 SUBSECTION
  54         typedef arelent
  55
  56         This is the structure of a relocation entry:
  57
  58 CODE_FRAGMENT
  59 .
  60 .typedef enum bfd_reloc_status
  61 .{
  62 .       {* No errors detected *}
  63 .  bfd_reloc_ok,
  64 .
  65 .       {* The relocation was performed, but there was an overflow. *}
  66 .  bfd_reloc_overflow,
  67 .
  68 .       {* The address to relocate was not within the section supplied. *}
  69 .  bfd_reloc_outofrange,
  70 .
  71 .       {* Used by special functions *}
  72 .  bfd_reloc_continue,
  73 .
  74 .       {* Unused *}
  75 .  bfd_reloc_notsupported,
  76 .
  77 .       {* Unsupported relocation size requested. *}
  78 .  bfd_reloc_other,
  79 .
  80 .       {* The symbol to relocate against was undefined. *}
  81 .  bfd_reloc_undefined,
  82 .
  83 .       {* The relocation was performed, but may not be ok - presently
  84 .          generated only when linking i960 coff files with i960 b.out
  85 .          symbols. *}
  86 .  bfd_reloc_dangerous
  87 . }
  88 . bfd_reloc_status_type;
  89 .
  90 .
  91 .typedef struct reloc_cache_entry
  92 .{
  93 .       {* A pointer into the canonical table of pointers  *}
  94 .  struct symbol_cache_entry **sym_ptr_ptr;
  95 .
  96 .       {* offset in section *}
  97 .  bfd_size_type address;
  98 .
  99 .       {* addend for relocation value *}
 100 .  bfd_vma addend;
 101 .
 102 .       {* Pointer to how to perform the required relocation *}
 103 .  CONST struct reloc_howto_struct *howto;
 104 .
 105 .} arelent;
 106
 107 */
 108
 109 /*
 110 DESCRIPTION
 111
 112         Here is a description of each of the fields within a relent:
 113
 114         o sym_ptr_ptr
 115
 116         The symbol table pointer points to a pointer to the symbol
 117         associated with the relocation request. This would naturally
 118         be the pointer into the table returned by the back end's
 119         get_symtab action. @xref{Symbols}. The symbol is referenced
 120         through a pointer to a pointer so that tools like the linker
 121         can fix up all the symbols of the same name by modifying only
 122         one pointer. The relocation routine looks in the symbol and
 123         uses the base of the section the symbol is attached to and the
 124         value of the symbol as the initial relocation offset. If the
 125         symbol pointer is zero, then the section provided is looked up.
 126
 127         o address
 128
 129         The address field gives the offset in bytes from the base of
 130         the section data which owns the relocation record to the first
 131         byte of relocatable information. The actual data relocated
 132         will be relative to this point - for example, a relocation
 133         type which modifies the bottom two bytes of a four byte word
 134         would not touch the first byte pointed to in a big endian
 135         world.
 136
 137         o addend
 138
 139         The addend is a value provided by the back end to be added (!)
 140         to the relocation offset. Its interpretation is dependent upon
 141         the howto. For example, on the 68k the code:
 142
 143
 144 |        char foo[];
 145 |        main()
 146 |                {
 147 |                return foo[0x12345678];
 148 |                }
 149
 150         Could be compiled into:
 151
 152 |        linkw fp,#-4
 153 |        moveb @@#12345678,d0
 154 |        extbl d0
 155 |        unlk fp
 156 |        rts
 157
 158
 159         This could create a reloc pointing to foo, but leave the
 160         offset in the data (something like)
 161
 162
 163 |RELOCATION RECORDS FOR [.text]:
 164 |offset   type      value
 165 |00000006 32        _foo
 166 |
 167 |00000000 4e56 fffc          ; linkw fp,#-4
 168 |00000004 1039 1234 5678     ; moveb @@#12345678,d0
 169 |0000000a 49c0               ; extbl d0
 170 |0000000c 4e5e               ; unlk fp
 171 |0000000e 4e75               ; rts
 172
 173
 174         Using coff and an 88k, some instructions don't have enough
 175         space in them to represent the full address range, and
 176         pointers have to be loaded in two parts. So you'd get something like:
 177
 178
 179 |        or.u     r13,r0,hi16(_foo+0x12345678)
 180 |        ld.b     r2,r13,lo16(_foo+0x12345678)
 181 |        jmp      r1
 182
 183
 184         This should create two relocs, both pointing to _foo, and with
 185         0x12340000 in their addend field. The data would consist of:
 186
 187
 188 |RELOCATION RECORDS FOR [.text]:
 189 |offset   type      value
 190 |00000002 HVRT16    _foo+0x12340000
 191 |00000006 LVRT16    _foo+0x12340000
 192
 193 |00000000 5da05678           ; or.u r13,r0,0x5678
 194 |00000004 1c4d5678           ; ld.b r2,r13,0x5678
 195 |00000008 f400c001           ; jmp r1
 196
 197
 198         The relocation routine digs out the value from the data, adds
 199         it to the addend to get the original offset and then adds the
 200         value of _foo. Note that all 32 bits have to be kept around
 201         somewhere, to cope with carry from bit 15 to bit 16.
 202
 203         One further example is the sparc and the a.out format. The
 204         sparc has a similar problem to the 88k, in that some
 205         instructions don't have room for an entire offset, but on the
 206         sparc the parts are created odd sized lumps. The designers of
 207         the a.out format chose not to use the data within the section
 208         for storing part of the offset; all the offset is kept within
 209         the reloc. Any thing in the data should be ignored.
 210
 211 |        save %sp,-112,%sp
 212 |        sethi %hi(_foo+0x12345678),%g2
 213 |        ldsb [%g2+%lo(_foo+0x12345678)],%i0
 214 |        ret
 215 |        restore
 216
 217         Both relocs contains a pointer to foo, and the offsets would
 218         contain junk.
 219
 220
 221 |RELOCATION RECORDS FOR [.text]:
 222 |offset   type      value
 223 |00000004 HI22      _foo+0x12345678
 224 |00000008 LO10      _foo+0x12345678
 225
 226 |00000000 9de3bf90     ; save %sp,-112,%sp
 227 |00000004 05000000     ; sethi %hi(_foo+0),%g2
 228 |00000008 f048a000     ; ldsb [%g2+%lo(_foo+0)],%i0
 229 |0000000c 81c7e008     ; ret
 230 |00000010 81e80000     ; restore
 231
 232
 233         o howto
 234
 235         The howto field can be imagined as a
 236         relocation instruction. It is a pointer to a struct which
 237         contains information on what to do with all the other
 238         information in the reloc record and data section. A back end
 239         would normally have a relocation instruction set and turn
 240         relocations into pointers to the correct structure on input -
 241         but it would be possible to create each howto field on demand.
 242
 243 */
 244
 245 /*
 246 SUBSUBSECTION
 247         <<enum complain_overflow>>
 248
 249         Indicates what sort of overflow checking should be done when
 250         performing a relocation.
 251
 252 CODE_FRAGMENT
 253 .
 254 .enum complain_overflow
 255 .{
 256 .       {* Do not complain on overflow. *}
 257 .  complain_overflow_dont,
 258 .
 259 .       {* Complain if the bitfield overflows, whether it is considered
 260 .          as signed or unsigned. *}
 261 .  complain_overflow_bitfield,
 262 .
 263 .       {* Complain if the value overflows when considered as signed
 264 .          number. *}
 265 .  complain_overflow_signed,
 266 .
 267 .       {* Complain if the value overflows when considered as an
 268 .          unsigned number. *}
 269 .  complain_overflow_unsigned
 270 .};
 271
 272 */
 273
 274 /*
 275 SUBSUBSECTION
 276         <<reloc_howto_type>>
 277
 278         The <<reloc_howto_type>> is a structure which contains all the
 279         information that BFD needs to know to tie up a back end's data.
 280
 281 CODE_FRAGMENT
 282 .struct symbol_cache_entry;             {* Forward declaration *}
 283 .
 284 .typedef CONST struct reloc_howto_struct
 285 .{
 286 .       {*  The type field has mainly a documetary use - the back end can
 287 .           to what it wants with it, though the normally the back end's
 288 .           external idea of what a reloc number would be would be stored
 289 .           in this field. For example, the a PC relative word relocation
 290 .           in a coff environment would have the type 023 - because that's
 291 .           what the outside world calls a R_PCRWORD reloc. *}
 292 .  unsigned int type;
 293 .
 294 .       {*  The value the final relocation is shifted right by. This drops
 295 .           unwanted data from the relocation.  *}
 296 .  unsigned int rightshift;
 297 .
 298 .       {*  The size of the item to be relocated - 0, is one byte, 1 is 2
 299 .           bytes, 2 is four bytes.  A negative value indicates that the
 300 .           result is to be subtracted from the data.  *}
 301 .  int size;
 302 .
 303 .       {*  The number of bits in the item to be relocated.  This is used
 304 .           when doing overflow checking.  *}
 305 .  unsigned int bitsize;
 306 .
 307 .       {*  Notes that the relocation is relative to the location in the
 308 .           data section of the addend. The relocation function will
 309 .           subtract from the relocation value the address of the location
 310 .           being relocated. *}
 311 .  boolean pc_relative;
 312 .
 313 .       {*  The bit position of the reloc value in the destination.
 314 .           The relocated value is left shifted by this amount. *}
 315 .  unsigned int bitpos;
 316 .
 317 .       {* What type of overflow error should be checked for when
 318 .          relocating. *}
 319 .  enum complain_overflow complain_on_overflow;
 320 .
 321 .       {* If this field is non null, then the supplied function is
 322 .          called rather than the normal function. This allows really
 323 .          strange relocation methods to be accomodated (e.g., i960 callj
 324 .          instructions). *}
 325 .  bfd_reloc_status_type (*special_function)
 326 .                                   PARAMS ((bfd *abfd,
 327 .                                            arelent *reloc_entry,
 328 .                                            struct symbol_cache_entry *symbol,
 329 .                                            PTR data,
 330 .                                            asection *input_section,
 331 .                                            bfd *output_bfd));
 332 .
 333 .       {* The textual name of the relocation type. *}
 334 .  char *name;
 335 .
 336 .       {* When performing a partial link, some formats must modify the
 337 .          relocations rather than the data - this flag signals this.*}
 338 .  boolean partial_inplace;
 339 .
 340 .       {* The src_mask is used to select what parts of the read in data
 341 .          are to be used in the relocation sum.  E.g., if this was an 8 bit
 342 .          bit of data which we read and relocated, this would be
 343 .          0x000000ff. When we have relocs which have an addend, such as
 344 .          sun4 extended relocs, the value in the offset part of a
 345 .          relocating field is garbage so we never use it. In this case
 346 .          the mask would be 0x00000000. *}
 347 .  bfd_vma src_mask;
 348 .
 349 .       {* The dst_mask is what parts of the instruction are replaced
 350 .          into the instruction. In most cases src_mask == dst_mask,
 351 .          except in the above special case, where dst_mask would be
 352 .          0x000000ff, and src_mask would be 0x00000000.   *}
 353 .  bfd_vma dst_mask;
 354 .
 355 .       {* When some formats create PC relative instructions, they leave
 356 .          the value of the pc of the place being relocated in the offset
 357 .          slot of the instruction, so that a PC relative relocation can
 358 .          be made just by adding in an ordinary offset (e.g., sun3 a.out).
 359 .          Some formats leave the displacement part of an instruction
 360 .          empty (e.g., m88k bcs), this flag signals the fact.*}
 361 .  boolean pcrel_offset;
 362 .
 363 .} reloc_howto_type;
 364
 365 */
 366
 367 /*
 368 FUNCTION
 369         the HOWTO macro
 370
 371 DESCRIPTION
 372         The HOWTO define is horrible and will go away.
 373
 374
 375 .#define HOWTO(C, R,S,B, P, BI, O, SF, NAME, INPLACE, MASKSRC, MASKDST, PC) \
 376 .  {(unsigned)C,R,S,B, P, BI, O,SF,NAME,INPLACE,MASKSRC,MASKDST,PC}
 377
 378 DESCRIPTION
 379         And will be replaced with the totally magic way. But for the
 380         moment, we are compatible, so do it this way..
 381
 382
 383 .#define NEWHOWTO( FUNCTION, NAME,SIZE,REL,IN) HOWTO(0,0,SIZE,0,REL,0,complain_overflow_dont,FUNCTION, NAME,false,0,0,IN)
 384 .
 385 DESCRIPTION
 386         Helper routine to turn a symbol into a relocation value.
 387
 388 .#define HOWTO_PREPARE(relocation, symbol)      \
 389 .  {                                            \
 390 .  if (symbol != (asymbol *)NULL) {             \
 391 .    if (bfd_is_com_section (symbol->section)) { \
 392 .      relocation = 0;                          \
 393 .    }                                          \
 394 .    else {                                     \
 395 .      relocation = symbol->value;              \
 396 .    }                                          \
 397 .  }                                            \
 398 .}
 399
 400 */
 401
 402 /*
 403 TYPEDEF
 404         reloc_chain
 405
 406 DESCRIPTION
 407
 408         How relocs are tied together
 409
 410 .typedef unsigned char bfd_byte;
 411 .
 412 .typedef struct relent_chain {
 413 .  arelent relent;
 414 .  struct   relent_chain *next;
 415 .} arelent_chain;
 416
 417 */
 418
 419
 420
 421 /*
 422 FUNCTION
 423         bfd_perform_relocation
 424
 425 SYNOPSIS
 426         bfd_reloc_status_type
 427                 bfd_perform_relocation
 428                         (bfd * abfd,
 429                         arelent *reloc_entry,
 430                         PTR data,
 431                         asection *input_section,
 432                         bfd *output_bfd);
 433
 434 DESCRIPTION
 435         If an output_bfd is supplied to this function the generated
 436         image will be relocatable, the relocations are copied to the
 437         output file after they have been changed to reflect the new
 438         state of the world. There are two ways of reflecting the
 439         results of partial linkage in an output file; by modifying the
 440         output data in place, and by modifying the relocation record.
 441         Some native formats (e.g., basic a.out and basic coff) have no
 442         way of specifying an addend in the relocation type, so the
 443         addend has to go in the output data.  This is no big deal
 444         since in these formats the output data slot will always be big
 445         enough for the addend. Complex reloc types with addends were
 446         invented to solve just this problem.
 447
 448 */
 449
 450
 451 bfd_reloc_status_type
 452 DEFUN(bfd_perform_relocation,(abfd,
 453                               reloc_entry,
 454                               data,
 455                               input_section,
 456                               output_bfd),
 457       bfd *abfd AND
 458       arelent *reloc_entry AND
 459       PTR data AND
 460       asection *input_section AND
 461       bfd *output_bfd)
 462 {
 463   bfd_vma relocation;
 464   bfd_reloc_status_type flag = bfd_reloc_ok;
 465   bfd_size_type addr = reloc_entry->address ;
 466   bfd_vma output_base = 0;
 467   reloc_howto_type *howto = reloc_entry->howto;
 468   asection *reloc_target_output_section ;
 469
 470   asymbol *symbol;
 471
 472   symbol = *( reloc_entry->sym_ptr_ptr);
 473   if ((symbol->section == &bfd_abs_section)
 474       && output_bfd != (bfd *)NULL)
 475     {
 476       reloc_entry->address += input_section->output_offset;
 477       return bfd_reloc_ok;
 478     }
 479
 480   if ((symbol->section == &bfd_und_section) && output_bfd == (bfd *)NULL)
 481     flag = bfd_reloc_undefined;
 482
 483   /* If there is a function supplied to handle this relocation type,
 484      call it.  It'll return `bfd_reloc_continue' if further processing
 485      can be done.  */
 486   if (howto->special_function)
 487     {
 488       bfd_reloc_status_type cont;
 489       cont = howto->special_function (abfd, reloc_entry, symbol, data,
 490                                       input_section, output_bfd);
 491       if (cont != bfd_reloc_continue)
 492         return cont;
 493     }
 494
 495   /* Is the address of the relocation really within the section?  */
 496   if (reloc_entry->address > input_section->_cooked_size)
 497     return bfd_reloc_outofrange;
 498
 499   /* Work out which section the relocation is targetted at and the
 500      initial relocation command value.  */
 501
 502   /* Get symbol value.  (Common symbols are special.)  */
 503   if (bfd_is_com_section (symbol->section))
 504     relocation = 0;
 505   else
 506     relocation = symbol->value;
 507
 508
 509   reloc_target_output_section = symbol->section->output_section;
 510
 511   /* Convert input-section-relative symbol value to absolute.  */
 512   if (output_bfd && howto->partial_inplace==false)
 513     output_base = 0;
 514   else
 515     output_base = reloc_target_output_section->vma;
 516
 517   relocation += output_base + symbol->section->output_offset;
 518
 519   /* Add in supplied addend.  */
 520   relocation += reloc_entry->addend;
 521
 522   if (howto->pc_relative == true)
 523     {
 524       /* Anything which started out as pc relative should end up that
 525          way too.
 526
 527          There are two ways we can see a pcrel instruction. Sometimes
 528          the pcrel displacement has been partially calculated, it
 529          includes the distance from the start of the section to the
 530          instruction in it (e.g., sun3), and sometimes the field is
 531          totally blank - e.g., m88kbcs.  */
 532
 533       relocation -=
 534         input_section->output_section->vma + input_section->output_offset;
 535
 536       if (howto->pcrel_offset == true)
 537         relocation -= reloc_entry->address;
 538     }
 539
 540   if (output_bfd!= (bfd *)NULL)
 541     {
 542       if ( howto->partial_inplace == false)
 543         {
 544           /* This is a partial relocation, and we want to apply the relocation
 545              to the reloc entry rather than the raw data. Modify the reloc
 546              inplace to reflect what we now know.  */
 547           reloc_entry->addend = relocation;
 548           reloc_entry->address +=  input_section->output_offset;
 549           return flag;
 550         }
 551       else
 552         {
 553           /* This is a partial relocation, but inplace, so modify the
 554              reloc record a bit.
 555
 556              If we've relocated with a symbol with a section, change
 557              into a ref to the section belonging to the symbol.  */
 558
 559           reloc_entry->address += input_section->output_offset;
 560
 561           /* WTF?? */
 562           if (abfd->xvec->flavour == bfd_target_coff_flavour)
 563             {
 564               relocation -= reloc_entry->addend;
 565               reloc_entry->addend = 0;
 566             }
 567           else
 568             {
 569               reloc_entry->addend = relocation;
 570             }
 571         }
 572     }
 573   else
 574     {
 575       reloc_entry->addend = 0;
 576     }
 577
 578
 579   /* FIXME: This overflow checking is incomplete, because the value
 580      might have overflowed before we get here.  For a correct check we
 581      need to compute the value in a size larger than bitsize, but we
 582      can't reasonably do that for a reloc the same size as a host
 583      machine word.  */
 584   switch (howto->complain_on_overflow)
 585     {
 586     case complain_overflow_dont:
 587       break;
 588     case complain_overflow_signed:
 589       {
 590         /* Assumes two's complement.  */
 591         bfd_signed_vma reloc_signed_max = (1 << (howto->bitsize - 1)) - 1;
 592         bfd_signed_vma reloc_signed_min = ~ reloc_signed_max;
 593
 594         if ((bfd_signed_vma) relocation > reloc_signed_max
 595             || (bfd_signed_vma) relocation < reloc_signed_min)
 596           flag = bfd_reloc_overflow;
 597       }
 598       break;
 599     case complain_overflow_unsigned:
 600       {
 601         /* Assumes two's complement.  This expression avoids overflow
 602            if howto->bitsize is the number of bits in bfd_vma.  */
 603         bfd_vma reloc_unsigned_max =
 604           (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
 605
 606         if ((bfd_vma) relocation > reloc_unsigned_max)
 607           flag = bfd_reloc_overflow;
 608       }
 609       break;
 610     case complain_overflow_bitfield:
 611       {
 612         /* Assumes two's complement.  This expression avoids overflow
 613            if howto->bitsize is the number of bits in bfd_vma.  */
 614         bfd_vma reloc_bits = (((1 << (howto->bitsize - 1)) - 1) << 1) | 1;
 615
 616         if (((bfd_vma) relocation &~ reloc_bits) != 0
 617             && ((bfd_vma) relocation &~ reloc_bits) != (-1 &~ reloc_bits))
 618           flag = bfd_reloc_overflow;
 619       }
 620       break;
 621     default:
 622       abort ();
 623     }
 624
 625   /*
 626     Either we are relocating all the way, or we don't want to apply
 627     the relocation to the reloc entry (probably because there isn't
 628     any room in the output format to describe addends to relocs)
 629     */
 630   relocation >>= howto->rightshift;
 631
 632   /* Shift everything up to where it's going to be used */
 633
 634   relocation <<= howto->bitpos;
 635
 636   /* Wait for the day when all have the mask in them */
 637
 638   /* What we do:
 639      i instruction to be left alone
 640      o offset within instruction
 641      r relocation offset to apply
 642      S src mask
 643      D dst mask
 644      N ~dst mask
 645      A part 1
 646      B part 2
 647      R result
 648
 649      Do this:
 650      i i i i i o o o o o        from bfd_get<size>
 651      and           S S S S S    to get the size offset we want
 652      +   r r r r r r r r r r  to get the final value to place
 653      and           D D D D D  to chop to right size
 654      -----------------------
 655      A A A A A
 656      And this:
 657      ...   i i i i i o o o o o  from bfd_get<size>
 658      and   N N N N N            get instruction
 659      -----------------------
 660      ...   B B B B B
 661
 662      And then:
 663      B B B B B
 664      or              A A A A A
 665      -----------------------
 666      R R R R R R R R R R        put into bfd_put<size>
 667      */
 668
 669 #define DOIT(x) \
 670   x = ( (x & ~howto->dst_mask) | (((x & howto->src_mask) +  relocation) & howto->dst_mask))
 671
 672    switch (howto->size)
 673      {
 674      case 0:
 675        {
 676          char x = bfd_get_8(abfd, (char *)data + addr);
 677          DOIT(x);
 678          bfd_put_8(abfd,x, (unsigned char *) data + addr);
 679        }
 680        break;
 681
 682      case 1:
 683        if (relocation)
 684          {
 685            short x = bfd_get_16(abfd, (bfd_byte *)data + addr);
 686            DOIT(x);
 687            bfd_put_16(abfd, x,   (unsigned char *)data + addr);
 688          }
 689        break;
 690      case 2:
 691        if (relocation)
 692          {
 693            long  x = bfd_get_32 (abfd, (bfd_byte *) data + addr);
 694            DOIT (x);
 695            bfd_put_32 (abfd, x, (bfd_byte *)data + addr);
 696          }
 697        break;
 698      case -2:
 699        {
 700          long  x = bfd_get_32(abfd, (bfd_byte *) data + addr);
 701          relocation = -relocation;
 702          DOIT(x);
 703          bfd_put_32(abfd,x,    (bfd_byte *)data + addr);
 704        }
 705        break;
 706
 707      case 3:
 708
 709        /* Do nothing */
 710        break;
 711      default:
 712        return bfd_reloc_other;
 713      }
 714
 715   return flag;
 716 }
 717
 718
 719
 720 /*
 721 DOCDD
 722 INODE
 723         howto manager,  , typedef arelent, Relocations
 724
 725 SECTION
 726         The howto manager
 727
 728         When an application wants to create a relocation, but doesn't
 729         know what the target machine might call it, it can find out by
 730         using this bit of code.
 731
 732 */
 733
 734 /*
 735 TYPEDEF
 736         bfd_reloc_code_type
 737
 738 DESCRIPTION
 739         The insides of a reloc code
 740
 741 CODE_FRAGMENT
 742 .
 743 .typedef enum bfd_reloc_code_real
 744 .
 745 .{
 746 .       {* 64 bits wide, simple reloc *}
 747 .  BFD_RELOC_64,
 748 .       {* 64 bits, PC-relative *}
 749 .  BFD_RELOC_64_PCREL,
 750 .
 751 .       {* 32 bits wide, simple reloc *}
 752 .  BFD_RELOC_32,
 753 .       {* 32 bits, PC-relative *}
 754 .  BFD_RELOC_32_PCREL,
 755 .
 756 .       {* 16 bits wide, simple reloc *}
 757 .  BFD_RELOC_16,
 758 .       {* 16 bits, PC-relative *}
 759 .  BFD_RELOC_16_PCREL,
 760 .
 761 .       {* 8 bits wide, simple *}
 762 .  BFD_RELOC_8,
 763 .       {* 8 bits wide, pc relative *}
 764 .  BFD_RELOC_8_PCREL,
 765 .       {* 8 bits wide, but used to form an address like 0xffnn *}
 766 .  BFD_RELOC_8_FFnn,
 767 .
 768 .       {* The type of reloc used to build a contructor table - at the
 769 .          moment probably a 32 bit wide abs address, but the cpu can
 770 .          choose. *}
 771 .
 772 .  BFD_RELOC_CTOR,
 773 .
 774 .       {* High 22 bits of 32-bit value; simple reloc.  *}
 775 .  BFD_RELOC_HI22,
 776 .       {* Low 10 bits.  *}
 777 .  BFD_RELOC_LO10,
 778 .
 779 .       {* Reloc types used for i960/b.out.  *}
 780 .  BFD_RELOC_24_PCREL,
 781 .  BFD_RELOC_I960_CALLJ,
 782 .
 783 .       {* 32-bit pc-relative, shifted right 2 bits (i.e., 30-bit
 784 .          word displacement, e.g. for SPARC) *}
 785 .  BFD_RELOC_32_PCREL_S2,
 786 .
 787 .  {* now for the sparc/elf codes *}
 788 .  BFD_RELOC_NONE,              {* actually used *}
 789 .  BFD_RELOC_SPARC_WDISP22,
 790 .  BFD_RELOC_SPARC22,
 791 .  BFD_RELOC_SPARC13,
 792 .  BFD_RELOC_SPARC_GOT10,
 793 .  BFD_RELOC_SPARC_GOT13,
 794 .  BFD_RELOC_SPARC_GOT22,
 795 .  BFD_RELOC_SPARC_PC10,
 796 .  BFD_RELOC_SPARC_PC22,
 797 .  BFD_RELOC_SPARC_WPLT30,
 798 .  BFD_RELOC_SPARC_COPY,
 799 .  BFD_RELOC_SPARC_GLOB_DAT,
 800 .  BFD_RELOC_SPARC_JMP_SLOT,
 801 .  BFD_RELOC_SPARC_RELATIVE,
 802 .  BFD_RELOC_SPARC_UA32,
 803 .
 804 .  {* this one is a.out specific? *}
 805 .  BFD_RELOC_SPARC_BASE13,
 806 .  BFD_RELOC_SPARC_BASE22,
 807 .
 808 .  {* start-sanitize-v9 *}
 809 .  BFD_RELOC_SPARC_10,
 810 .  BFD_RELOC_SPARC_11,
 811 .#define  BFD_RELOC_SPARC_64 BFD_RELOC_64
 812 .  BFD_RELOC_SPARC_OLO10,
 813 .  BFD_RELOC_SPARC_HH22,
 814 .  BFD_RELOC_SPARC_HM10,
 815 .  BFD_RELOC_SPARC_LM22,
 816 .  BFD_RELOC_SPARC_PC_HH22,
 817 .  BFD_RELOC_SPARC_PC_HM10,
 818 .  BFD_RELOC_SPARC_PC_LM22,
 819 .  BFD_RELOC_SPARC_WDISP16,
 820 .  BFD_RELOC_SPARC_WDISP19,
 821 .  BFD_RELOC_SPARC_GLOB_JMP,
 822 .  BFD_RELOC_SPARC_LO7,
 823 .  {* end-sanitize-v9 *}
 824 .
 825 .       {* Bits 27..2 of the relocation address shifted right 2 bits;
 826 .         simple reloc otherwise.  *}
 827 .  BFD_RELOC_MIPS_JMP,
 828 .
 829 .       {* signed 16-bit pc-relative, shifted right 2 bits (e.g. for MIPS) *}
 830 .  BFD_RELOC_16_PCREL_S2,
 831 .
 832 .       {* High 16 bits of 32-bit value; simple reloc.  *}
 833 .  BFD_RELOC_HI16,
 834 .       {* High 16 bits of 32-bit value but the low 16 bits will be sign
 835 .          extended and added to form the final result.  If the low 16
 836 .          bits form a negative number, we need to add one to the high value
 837 .          to compensate for the borrow when the low bits are added.  *}
 838 .  BFD_RELOC_HI16_S,
 839 .       {* Low 16 bits.  *}
 840 .  BFD_RELOC_LO16,
 841 .
 842 .       {* 16 bit relocation relative to the global pointer.  *}
 843 .  BFD_RELOC_MIPS_GPREL,
 844 .
 845 .       {* These are, so far, specific to HPPA processors.  I'm not sure that
 846 .          some don't duplicate other reloc types, such as BFD_RELOC_32 and
 847 .          _32_PCREL.  Also, many more were in the list I got that don't
 848 .          fit in well in the model BFD uses, so I've omitted them for now.
 849 .          If we do make this reloc type get used for code that really does
 850 .          implement the funky reloc types, they'll have to be added to this
 851 .          list.   *}
 852 .  BFD_RELOC_HPPA_32,
 853 .  BFD_RELOC_HPPA_11,
 854 .  BFD_RELOC_HPPA_14,
 855 .  BFD_RELOC_HPPA_17,
 856 .  BFD_RELOC_HPPA_L21,
 857 .  BFD_RELOC_HPPA_R11,
 858 .  BFD_RELOC_HPPA_R14,
 859 .  BFD_RELOC_HPPA_R17,
 860 .  BFD_RELOC_HPPA_LS21,
 861 .  BFD_RELOC_HPPA_RS11,
 862 .  BFD_RELOC_HPPA_RS14,
 863 .  BFD_RELOC_HPPA_RS17,
 864 .  BFD_RELOC_HPPA_LD21,
 865 .  BFD_RELOC_HPPA_RD11,
 866 .  BFD_RELOC_HPPA_RD14,
 867 .  BFD_RELOC_HPPA_RD17,
 868 .  BFD_RELOC_HPPA_LR21,
 869 .  BFD_RELOC_HPPA_RR14,
 870 .  BFD_RELOC_HPPA_RR17,
 871 .  BFD_RELOC_HPPA_GOTOFF_11,
 872 .  BFD_RELOC_HPPA_GOTOFF_14,
 873 .  BFD_RELOC_HPPA_GOTOFF_L21,
 874 .  BFD_RELOC_HPPA_GOTOFF_R11,
 875 .  BFD_RELOC_HPPA_GOTOFF_R14,
 876 .  BFD_RELOC_HPPA_GOTOFF_LS21,
 877 .  BFD_RELOC_HPPA_GOTOFF_RS11,
 878 .  BFD_RELOC_HPPA_GOTOFF_RS14,
 879 .  BFD_RELOC_HPPA_GOTOFF_LD21,
 880 .  BFD_RELOC_HPPA_GOTOFF_RD11,
 881 .  BFD_RELOC_HPPA_GOTOFF_RD14,
 882 .  BFD_RELOC_HPPA_GOTOFF_LR21,
 883 .  BFD_RELOC_HPPA_GOTOFF_RR14,
 884 .  BFD_RELOC_HPPA_DLT_32,
 885 .  BFD_RELOC_HPPA_DLT_11,
 886 .  BFD_RELOC_HPPA_DLT_14,
 887 .  BFD_RELOC_HPPA_DLT_L21,
 888 .  BFD_RELOC_HPPA_DLT_R11,
 889 .  BFD_RELOC_HPPA_DLT_R14,
 890 .  BFD_RELOC_HPPA_ABS_CALL_11,
 891 .  BFD_RELOC_HPPA_ABS_CALL_14,
 892 .  BFD_RELOC_HPPA_ABS_CALL_17,
 893 .  BFD_RELOC_HPPA_ABS_CALL_L21,
 894 .  BFD_RELOC_HPPA_ABS_CALL_R11,
 895 .  BFD_RELOC_HPPA_ABS_CALL_R14,
 896 .  BFD_RELOC_HPPA_ABS_CALL_R17,
 897 .  BFD_RELOC_HPPA_ABS_CALL_LS21,
 898 .  BFD_RELOC_HPPA_ABS_CALL_RS11,
 899 .  BFD_RELOC_HPPA_ABS_CALL_RS14,
 900 .  BFD_RELOC_HPPA_ABS_CALL_RS17,
 901 .  BFD_RELOC_HPPA_ABS_CALL_LD21,
 902 .  BFD_RELOC_HPPA_ABS_CALL_RD11,
 903 .  BFD_RELOC_HPPA_ABS_CALL_RD14,
 904 .  BFD_RELOC_HPPA_ABS_CALL_RD17,
 905 .  BFD_RELOC_HPPA_ABS_CALL_LR21,
 906 .  BFD_RELOC_HPPA_ABS_CALL_RR14,
 907 .  BFD_RELOC_HPPA_ABS_CALL_RR17,
 908 .  BFD_RELOC_HPPA_PCREL_CALL_11,
 909 .  BFD_RELOC_HPPA_PCREL_CALL_12,
 910 .  BFD_RELOC_HPPA_PCREL_CALL_14,
 911 .  BFD_RELOC_HPPA_PCREL_CALL_17,
 912 .  BFD_RELOC_HPPA_PCREL_CALL_L21,
 913 .  BFD_RELOC_HPPA_PCREL_CALL_R11,
 914 .  BFD_RELOC_HPPA_PCREL_CALL_R14,
 915 .  BFD_RELOC_HPPA_PCREL_CALL_R17,
 916 .  BFD_RELOC_HPPA_PCREL_CALL_LS21,
 917 .  BFD_RELOC_HPPA_PCREL_CALL_RS11,
 918 .  BFD_RELOC_HPPA_PCREL_CALL_RS14,
 919 .  BFD_RELOC_HPPA_PCREL_CALL_RS17,
 920 .  BFD_RELOC_HPPA_PCREL_CALL_LD21,
 921 .  BFD_RELOC_HPPA_PCREL_CALL_RD11,
 922 .  BFD_RELOC_HPPA_PCREL_CALL_RD14,
 923 .  BFD_RELOC_HPPA_PCREL_CALL_RD17,
 924 .  BFD_RELOC_HPPA_PCREL_CALL_LR21,
 925 .  BFD_RELOC_HPPA_PCREL_CALL_RR14,
 926 .  BFD_RELOC_HPPA_PCREL_CALL_RR17,
 927 .  BFD_RELOC_HPPA_PLABEL_32,
 928 .  BFD_RELOC_HPPA_PLABEL_11,
 929 .  BFD_RELOC_HPPA_PLABEL_14,
 930 .  BFD_RELOC_HPPA_PLABEL_L21,
 931 .  BFD_RELOC_HPPA_PLABEL_R11,
 932 .  BFD_RELOC_HPPA_PLABEL_R14,
 933 .  BFD_RELOC_HPPA_UNWIND_ENTRY,
 934 .  BFD_RELOC_HPPA_UNWIND_ENTRIES,
 935 .
 936 .  {* this must be the highest numeric value *}
 937 .  BFD_RELOC_UNUSED
 938 . } bfd_reloc_code_real_type;
 939 */
 940
 941
 942
 943 /*
 944 SECTION
 945         bfd_reloc_type_lookup
 946
 947 SYNOPSIS
 948         CONST struct reloc_howto_struct *
 949         bfd_reloc_type_lookup (bfd *abfd, bfd_reloc_code_real_type code);
 950
 951 DESCRIPTION
 952         This routine returns a pointer to a howto struct which when
 953         invoked, will perform the supplied relocation on data from the
 954         architecture noted.
 955
 956 */
 957
 958
 959 CONST struct reloc_howto_struct *
 960 DEFUN(bfd_reloc_type_lookup,(abfd, code),
 961       bfd *abfd AND
 962       bfd_reloc_code_real_type code)
 963 {
 964   return BFD_SEND (abfd, reloc_type_lookup, (abfd, code));
 965 }
 966
 967 static reloc_howto_type bfd_howto_32 =
 968  HOWTO(0, 00,2,32,false,0,complain_overflow_bitfield,0,"VRT32", false,0xffffffff,0xffffffff,true);
 969
 970
 971 /*
 972 INTERNAL_FUNCTION
 973         bfd_default_reloc_type_lookup
 974
 975 SYNOPSIS
 976         CONST struct reloc_howto_struct *bfd_default_reloc_type_lookup
 977         (bfd *abfd AND
 978          bfd_reloc_code_real_type  code);
 979
 980 DESCRIPTION
 981         Provides a default relocation lookup routine for any architecture.
 982
 983
 984 */
 985
 986 CONST struct reloc_howto_struct *
 987 DEFUN(bfd_default_reloc_type_lookup, (abfd, code),
 988       bfd *abfd AND
 989       bfd_reloc_code_real_type code)
 990 {
 991   switch (code)
 992     {
 993     case BFD_RELOC_CTOR:
 994       /* The type of reloc used in a ctor, which will be as wide as the
 995          address - so either a 64, 32, or 16 bitter.. */
 996       switch (bfd_get_arch_info (abfd)->bits_per_address) {
 997       case 64:
 998         BFD_FAIL();
 999       case 32:
1000         return &bfd_howto_32;
1001       case 16:
1002         BFD_FAIL();
1003       default:
1004         BFD_FAIL();
1005       }
1006     default:
1007       BFD_FAIL();
1008     }
1009   return (CONST struct reloc_howto_struct *)NULL;
1010 }
1011
1012
1013 /*
1014 INTERNAL_FUNCTION
1015         bfd_generic_relax_section
1016
1017 SYNOPSIS
1018         boolean bfd_generic_relax_section
1019          (bfd *abfd,
1020           asection *section,
1021           asymbol **symbols);
1022
1023 DESCRIPTION
1024         Provides default handling for relaxing for back ends which
1025         don't do relaxing -- i.e., does nothing.
1026 */
1027
1028 boolean
1029 DEFUN(bfd_generic_relax_section,(abfd, section, symbols),
1030       bfd *abfd AND
1031       asection *section AND
1032       asymbol **symbols)
1033 {
1034
1035   return false;
1036
1037 }
1038
1039
1040 /*
1041 INTERNAL_FUNCTION
1042         bfd_generic_get_relocated_section_contents
1043
1044 SYNOPSIS
1045         bfd_byte *
1046            bfd_generic_get_relocated_section_contents (bfd *abfd,
1047              struct bfd_seclet *seclet,
1048              bfd_byte *data,
1049              boolean relocateable);
1050
1051 DESCRIPTION
1052         Provides default handling of relocation effort for back ends
1053         which can't be bothered to do it efficiently.
1054
1055 */
1056
1057 bfd_byte *
1058 DEFUN(bfd_generic_get_relocated_section_contents,(abfd,
1059                                                   seclet,
1060                                                   data,
1061                                                   relocateable),
1062       bfd *abfd AND
1063       struct bfd_seclet *seclet AND
1064       bfd_byte *data AND
1065       boolean relocateable)
1066 {
1067   extern bfd_error_vector_type bfd_error_vector;
1068
1069   /* Get enough memory to hold the stuff */
1070   bfd *input_bfd = seclet->u.indirect.section->owner;
1071   asection *input_section = seclet->u.indirect.section;
1072
1073
1074
1075   size_t reloc_size = bfd_get_reloc_upper_bound(input_bfd, input_section);
1076   arelent **reloc_vector = (arelent **) alloca(reloc_size);
1077
1078   /* read in the section */
1079   bfd_get_section_contents(input_bfd,
1080                            input_section,
1081                            data,
1082                            0,
1083                            input_section->_raw_size);
1084
1085 /* We're not relaxing the section, so just copy the size info */
1086   input_section->_cooked_size = input_section->_raw_size;
1087   input_section->reloc_done = true;
1088
1089
1090   if (bfd_canonicalize_reloc(input_bfd,
1091                              input_section,
1092                              reloc_vector,
1093                              seclet->u.indirect.symbols) )
1094   {
1095     arelent **parent;
1096     for (parent = reloc_vector;  * parent != (arelent *)NULL;
1097          parent++)
1098     {
1099       bfd_reloc_status_type r=
1100        bfd_perform_relocation(input_bfd,
1101                               *parent,
1102                               data,
1103                               input_section,
1104                               relocateable ? abfd : (bfd *) NULL);
1105
1106       if (relocateable)
1107         {
1108           asection *os = input_section->output_section;
1109
1110           /* A partial link, so keep the relocs */
1111           os->orelocation[os->reloc_count] = *parent;
1112           os->reloc_count++;
1113         }
1114
1115       if (r != bfd_reloc_ok)
1116       {
1117         switch (r)
1118         {
1119         case bfd_reloc_undefined:
1120           bfd_error_vector.undefined_symbol(*parent, seclet);
1121           break;
1122         case bfd_reloc_dangerous:
1123           bfd_error_vector.reloc_dangerous(*parent, seclet);
1124           break;
1125         case bfd_reloc_outofrange:
1126         case bfd_reloc_overflow:
1127           bfd_error_vector.reloc_value_truncated(*parent, seclet);
1128           break;
1129         default:
1130           abort();
1131           break;
1132         }
1133
1134       }
1135     }
1136   }
1137
1138
1139   return data;
1140
1141
1142 }