bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright 2000 Free Software Foundation, Inc.
   3    Contributed by Axis Communications AB.
   4    Written by Hans-Peter Nilsson.
   5
   6 This file is part of BFD, the Binary File Descriptor library.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 /* See info in the file PORTING for documentation of these macros and
  23    functions.  Beware; some of the information there is outdated.  */
  24
  25 #define N_HEADER_IN_TEXT(x) 0
  26 #define BYTES_IN_WORD 4
  27 #define N_TXTOFF(x) 32
  28 #define ENTRY_CAN_BE_ZERO
  29 #define TEXT_START_ADDR 0
  30
  31 /* Without reading symbols to get the text start symbol, there is no way
  32    to know where the text segment starts in an a.out file.  Defaulting to
  33    anything as constant as TEXT_START_ADDR is bad.  But we can guess from
  34    the entry point, which is usually within the first 64k of the text
  35    segment.  We also assume here that the text segment is 64k-aligned.
  36    FIXME: It is also wrong to assume that data and bss follow immediately
  37    after text, but with those, we don't have any choice besides reading
  38    symbol info, and luckily there's no pressing need for correctness for
  39    those vma:s at this time.  */
  40 #define N_TXTADDR(x) ((x).a_entry & ~0xffff)
  41
  42 /* If you change this to 4, you can not link to an address N*4+2.  */
  43 #define SEGMENT_SIZE 2
  44
  45 /* For some reason, if the a.out file has Z_MAGIC, then
  46    adata(abfd).exec_bytes_size is not used, but rather
  47    adata(abfd).zmagic_disk_block_size, even though the exec_header is
  48    *not* included in the text segment.  A simple workaround is to
  49    #define ZMAGIC_DISK_BLOCK_SIZE, which is used if defined; otherwise
  50    TARGET_PAGE_SIZE is used.  */
  51 #define ZMAGIC_DISK_BLOCK_SIZE N_TXTOFF (0)
  52
  53 /* It seems odd at first to set a page-size this low, but gives greater
  54    freedom in where things can be linked.  The drawback is that you have
  55    to set alignment and padding in linker scripts.  */
  56 #define TARGET_PAGE_SIZE SEGMENT_SIZE
  57 #define TARGETNAME "a.out-cris"
  58
  59 /* N_SHARED_LIB gets this reasonable default as of 1999-07-12, but we
  60    have to work with 2.9.1.  Note that N_SHARED_LIB is used in a
  61    SUN-specific context, not applicable to CRIS.  */
  62 #define N_SHARED_LIB(x) 0
  63
  64 /* The definition here seems not used; just provided as a convention.  */
  65 #define DEFAULT_ARCH bfd_arch_cris
  66
  67 /* ??? Spacing might be essential for the parameters in this macro.
  68    Do Not Change.  */
  69 #define MY(OP) CAT (cris_aout_,OP)
  70 #define NAME(x,y) CAT3(cris_aout,_32_,y)
  71
  72 #include "bfd.h"
  73
  74 /* Version 1 of the header.  */
  75 #define MY_exec_hdr_flags 1
  76
  77 #define MY_write_object_contents MY(write_object_contents)
  78 static boolean MY(write_object_contents) PARAMS ((bfd *));
  79
  80 /* Forward this, so we can use a pointer to it in PARAMS.  */
  81 struct reloc_ext_external;
  82
  83 #define MY_swap_ext_reloc_out MY(swap_ext_reloc_out)
  84 static void MY(swap_ext_reloc_out) PARAMS ((bfd *, arelent *,
  85                                             struct reloc_ext_external *));
  86
  87 #define MY_swap_ext_reloc_in MY(swap_ext_reloc_in)
  88 static void MY(swap_ext_reloc_in) PARAMS ((bfd *, struct
  89                                            reloc_ext_external *,
  90                                            arelent *, asymbol **,
  91                                            bfd_size_type));
  92
  93 #define MY_set_sizes MY(set_sizes)
  94 static boolean MY(set_sizes) PARAMS ((bfd *));
  95
  96 /* To set back reloc_size to ext, we make MY(set_sizes) be called
  97    through this construct.  Note that MY_set_arch_mach is only called
  98    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  99    not call set_sizes.  */
 100
 101 #define MY_set_arch_mach NAME (aout, set_arch_mach)
 102 #define SET_ARCH_MACH(BFD, EXEC) \
 103  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
 104
 105 /* These macros describe the binary layout of the reloc information we
 106    use in a file.  */
 107 #define RELOC_EXT_BITS_EXTERN_LITTLE 0x80
 108 #define RELOC_EXT_BITS_TYPE_LITTLE 3
 109 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 110
 111 #ifndef MY_get_section_contents
 112 #define MY_get_section_contents aout_32_get_section_contents
 113 #endif
 114
 115 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 116
 117 /* Include generic functions (some are overridden above).  */
 118 #include "aout32.c"
 119 #include "aout-target.h"
 120
 121 /* We need our own version to set header flags.  */
 122
 123 static boolean
 124 MY(write_object_contents) (abfd)
 125      bfd *abfd;
 126 {
 127   struct external_exec exec_bytes;
 128   struct internal_exec *execp = exec_hdr (abfd);
 129
 130   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 131      seems unnecessary when inspecting as and ld behavior (not an
 132      exhaustive inspection).  The default write_object_contents
 133      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 134   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 135
 136   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 137      the default definition.  */
 138   if (bfd_get_arch(abfd) == bfd_arch_cris)
 139     N_SET_MACHTYPE(*execp, M_CRIS);
 140
 141   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 142
 143   WRITE_HEADERS (abfd, execp);
 144
 145   return true;
 146 }
 147
 148 /* We need our own for these reasons:
 149    - Assert that a normal 8, 16 or 32 reloc is output.
 150    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 151
 152 static void
 153 MY(swap_ext_reloc_out) (abfd, g, natptr)
 154      bfd *abfd;
 155      arelent *g;
 156      struct reloc_ext_external *natptr;
 157 {
 158   int r_index;
 159   int r_extern;
 160   unsigned int r_type;
 161   unsigned int r_addend;
 162   asymbol *sym = *(g->sym_ptr_ptr);
 163   asection *output_section = sym->section->output_section;
 164
 165   PUT_WORD (abfd, g->address, natptr->r_address);
 166
 167   r_type = (unsigned int) g->howto->type;
 168
 169   r_addend = g->addend;
 170   if ((sym->flags & BSF_SECTION_SYM) != 0)
 171     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 172
 173   /* If this relocation is relative to a symbol then set the
 174      r_index to the symbols index, and the r_extern bit.
 175
 176      Absolute symbols can come in in two ways, either as an offset
 177      from the abs section, or as a symbol which has an abs value.
 178      check for that here.  */
 179
 180   if (bfd_is_abs_section (bfd_get_section (sym)))
 181     {
 182       r_extern = 0;
 183       r_index = N_ABS;
 184     }
 185   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 186     {
 187       if (bfd_is_und_section (bfd_get_section (sym))
 188           /* Remember to check for weak symbols; they count as global.  */
 189           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 190         r_extern = 1;
 191       else
 192         r_extern = 0;
 193       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 194     }
 195   else
 196     {
 197       /* Just an ordinary section.  */
 198       r_extern = 0;
 199       r_index = output_section->target_index;
 200     }
 201
 202   /* The relocation type is the same as the canonical ones, but only
 203      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 204      We may change this later, but assert this for the moment.  */
 205   if (r_type > 2)
 206     {
 207       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 208                              bfd_get_filename (abfd), r_type);
 209
 210       bfd_set_error (bfd_error_wrong_format);
 211     }
 212
 213   /* Now the fun stuff.  */
 214   natptr->r_index[2] = r_index >> 16;
 215   natptr->r_index[1] = r_index >> 8;
 216   natptr->r_index[0] = r_index;
 217   natptr->r_type[0] =
 218      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 219       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 220
 221   PUT_WORD (abfd, r_addend, natptr->r_addend);
 222 }
 223
 224 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 225
 226 static void
 227 MY(swap_ext_reloc_in) (abfd, bytes, cache_ptr, symbols, symcount)
 228      bfd *abfd;
 229      struct reloc_ext_external *bytes;
 230      arelent *cache_ptr;
 231      asymbol **symbols;
 232      bfd_size_type symcount;
 233 {
 234   unsigned int r_index;
 235   int r_extern;
 236   unsigned int r_type;
 237   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 238
 239   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 240
 241   /* Now the fun stuff.  */
 242   r_index =  (bytes->r_index[2] << 16)
 243     | (bytes->r_index[1] << 8)
 244     |  bytes->r_index[0];
 245   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 246   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 247     & RELOC_EXT_BITS_TYPE_LITTLE;
 248
 249   if (r_type > 2)
 250     {
 251       (*_bfd_error_handler) (_("%s: Invalid relocation type imported: %d"),
 252                              bfd_get_filename (abfd), r_type);
 253
 254       bfd_set_error(bfd_error_wrong_format);
 255     }
 256
 257   cache_ptr->howto =  howto_table_ext + r_type;
 258
 259   if (r_extern && r_index > symcount)
 260     {
 261       (*_bfd_error_handler)
 262         (_("%s: Bad relocation record imported: %d"),
 263          bfd_get_filename (abfd), r_index);
 264
 265       bfd_set_error (bfd_error_wrong_format);
 266
 267       /* We continue, so we can catch further errors.  */
 268       r_extern = 0;
 269       r_index = N_ABS;
 270     }
 271
 272   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 273      default.  */
 274   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 275 }
 276
 277 /* We use the same as the default, except that we also set
 278    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 279    NAME (aout, set_arch_mach) in aoutx.  */
 280
 281 static boolean
 282 MY(set_sizes) (abfd)
 283      bfd *abfd;
 284 {
 285   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 286
 287   adata(abfd).page_size = TARGET_PAGE_SIZE;
 288   adata(abfd).segment_size = SEGMENT_SIZE;
 289   adata(abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 290   adata(abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 291
 292   /* ... except for that we have the extended reloc.  The alternative
 293      would be to add a check on bfd_arch_cris in NAME (aout,
 294      set_arch_mach) in aoutx.h, but I don't want to do that since
 295      target-specific things should not be added there.  */
 296
 297   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 298
 299   return true;
 300 }
 301
 302 /*
 303  * Local variables:
 304  * eval: (c-set-style "gnu")
 305  * indent-tabs-mode: t
 306  * End:
 307  */