bfd/cf-m68klynx.c

   1 /* BFD back-end for Motorola M68K COFF LynxOS files.
   2    Copyright 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 #define TARGET_SYM      m68klynx_coff_vec
  22 #define TARGET_NAME     "coff-m68k-lynx"
  23
  24 #define LYNXOS
  25
  26 #define COFF_LONG_FILENAMES
  27
  28 #define _bfd_m68kcoff_howto_table _bfd_m68klynx_howto_table
  29 #define _bfd_m68kcoff_rtype2howto _bfd_m68klynx_rtype2howto
  30 #define _bfd_m68kcoff_howto2rtype _bfd_m68klynx_howto2rtype
  31
  32 #define LYNX_SPECIAL_FN _bfd_m68klynx_special_fn
  33
  34 #include "bfd.h"
  35 #include "sysdep.h"
  36
  37 static bfd_reloc_status_type _bfd_m68klynx_special_fn PARAMS ((bfd *abfd,
  38                                                       arelent *reloc_entry,
  39                                                       asymbol *symbol,
  40                                                       PTR data,
  41                                                       asection *input_section,
  42                                                       bfd *output_bfd,
  43                                                       char **error_message));
  44
  45 /* For some reason when using m68k COFF the value stored in the .text
  46    section for a reference to a common symbol is the value itself plus
  47    any desired offset.  (taken from work done by Ian Taylor, Cygnus Support,
  48    for I386 COFF).  */
  49
  50 /* If we are producing relocateable output, we need to do some
  51    adjustments to the object file that are not done by the
  52    bfd_perform_relocation function.  This function is called by every
  53    reloc type to make any required adjustments.  */
  54
  55 static bfd_reloc_status_type
  56 _bfd_m68klynx_special_fn (abfd, reloc_entry, symbol, data, input_section, output_bfd,
  57                           error_message)
  58      bfd *abfd;
  59      arelent *reloc_entry;
  60      asymbol *symbol;
  61      PTR data;
  62      asection *input_section;
  63      bfd *output_bfd;
  64      char **error_message;
  65 {
  66   symvalue diff;
  67
  68   if (output_bfd == (bfd *) NULL)
  69     return bfd_reloc_continue;
  70
  71   if (bfd_is_com_section (symbol->section))
  72     {
  73       /* We are relocating a common symbol.  The current value in the
  74          object file is ORIG + OFFSET, where ORIG is the value of the
  75          common symbol as seen by the object file when it was compiled
  76          (this may be zero if the symbol was undefined) and OFFSET is
  77          the offset into the common symbol (normally zero, but may be
  78          non-zero when referring to a field in a common structure).
  79          ORIG is the negative of reloc_entry->addend, which is set by
  80          the CALC_ADDEND macro below.  We want to replace the value in
  81          the object file with NEW + OFFSET, where NEW is the value of
  82          the common symbol which we are going to put in the final
  83          object file.  NEW is symbol->value.  */
  84       diff = symbol->value + reloc_entry->addend;
  85     }
  86   else
  87     {
  88       /* For some reason bfd_perform_relocation always effectively
  89          ignores the addend for a COFF target when producing
  90          relocateable output.  This seems to be always wrong for 386
  91          COFF, so we handle the addend here instead.  */
  92       diff = reloc_entry->addend;
  93     }
  94
  95 #define DOIT(x) \
  96   x = ((x & ~howto->dst_mask) | (((x & howto->src_mask) + diff) & howto->dst_mask))
  97
  98   if (diff != 0)
  99     {
 100       const reloc_howto_type *howto = reloc_entry->howto;
 101       unsigned char *addr = (unsigned char *) data + reloc_entry->address;
 102
 103       switch (howto->size)
 104         {
 105         case 0:
 106           {
 107             char x = bfd_get_8 (abfd, addr);
 108             DOIT (x);
 109             bfd_put_8 (abfd, x, addr);
 110           }
 111           break;
 112
 113         case 1:
 114           {
 115             short x = bfd_get_16 (abfd, addr);
 116             DOIT (x);
 117             bfd_put_16 (abfd, x, addr);
 118           }
 119           break;
 120
 121         case 2:
 122           {
 123             long x = bfd_get_32 (abfd, addr);
 124             DOIT (x);
 125             bfd_put_32 (abfd, x, addr);
 126           }
 127           break;
 128
 129         default:
 130           abort ();
 131         }
 132     }
 133
 134   /* Now let bfd_perform_relocation finish everything up.  */
 135   return bfd_reloc_continue;
 136 }
 137 /* Compute the addend of a reloc.  If the reloc is to a common symbol,
 138    the object file contains the value of the common symbol.  By the
 139    time this is called, the linker may be using a different symbol
 140    from a different object file with a different value.  Therefore, we
 141    hack wildly to locate the original symbol from this file so that we
 142    can make the correct adjustment.  This macro sets coffsym to the
 143    symbol from the original file, and uses it to set the addend value
 144    correctly.  If this is not a common symbol, the usual addend
 145    calculation is done, except that an additional tweak is needed for
 146    PC relative relocs.
 147    FIXME: This macro refers to symbols and asect; these are from the
 148    calling function, not the macro arguments.  */
 149
 150 #define CALC_ADDEND(abfd, ptr, reloc, cache_ptr)                \
 151   {                                                             \
 152     coff_symbol_type *coffsym = (coff_symbol_type *) NULL;      \
 153     if (ptr && bfd_asymbol_bfd (ptr) != abfd)                   \
 154       coffsym = (obj_symbols (abfd)                             \
 155                  + (cache_ptr->sym_ptr_ptr - symbols));         \
 156     else if (ptr)                                               \
 157       coffsym = coff_symbol_from (abfd, ptr);                   \
 158     if (coffsym != (coff_symbol_type *) NULL                    \
 159         && coffsym->native->u.syment.n_scnum == 0)              \
 160       cache_ptr->addend = - coffsym->native->u.syment.n_value;  \
 161     else if (ptr && bfd_asymbol_bfd (ptr) == abfd               \
 162              && ptr->section != (asection *) NULL)              \
 163       cache_ptr->addend = - (ptr->section->vma + ptr->value);   \
 164     else                                                        \
 165       cache_ptr->addend = 0;                                    \
 166     if (ptr && (reloc.r_type == R_PCRBYTE                       \
 167                 || reloc.r_type == R_PCRWORD                    \
 168                 || reloc.r_type == R_PCRLONG))                  \
 169       cache_ptr->addend += asect->vma;                          \
 170   }
 171
 172
 173 #include "coff-m68k.c"