bfd/aout-cris.c

   1 /* BFD backend for CRIS a.out binaries.
   2    Copyright 2000, 2001, 2002, 2003, 2004, 2005 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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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  Beware; some of the information there is outdated.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 N_TXTOFF(x)         32
  27 #define ENTRY_CAN_BE_ZERO
  28 #define TEXT_START_ADDR     0
  29
  30 /* Without reading symbols to get the text start symbol, there is no way
  31    to know where the text segment starts in an a.out file.  Defaulting to
  32    anything as constant as TEXT_START_ADDR is bad.  But we can guess from
  33    the entry point, which is usually within the first 64k of the text
  34    segment.  We also assume here that the text segment is 64k-aligned.
  35    FIXME: It is also wrong to assume that data and bss follow immediately
  36    after text, but with those, we don't have any choice besides reading
  37    symbol info, and luckily there's no pressing need for correctness for
  38    those vma:s at this time.  */
  39 #define N_TXTADDR(x) ((x).a_entry & ~(bfd_vma) 0xffff)
  40
  41 /* If you change this to 4, you can not link to an address N*4+2.  */
  42 #define SEGMENT_SIZE 2
  43
  44 /* For some reason, if the a.out file has Z_MAGIC, then
  45    adata(abfd).exec_bytes_size is not used, but rather
  46    adata(abfd).zmagic_disk_block_size, even though the exec_header is
  47    *not* included in the text segment.  A simple workaround is to
  48    #define ZMAGIC_DISK_BLOCK_SIZE, which is used if defined; otherwise
  49    TARGET_PAGE_SIZE is used.  */
  50 #define ZMAGIC_DISK_BLOCK_SIZE     N_TXTOFF (0)
  51
  52 /* It seems odd at first to set a page-size this low, but gives greater
  53    freedom in where things can be linked.  The drawback is that you have
  54    to set alignment and padding in linker scripts.  */
  55 #define TARGET_PAGE_SIZE SEGMENT_SIZE
  56 #define TARGETNAME "a.out-cris"
  57
  58 /* N_SHARED_LIB gets this reasonable default as of 1999-07-12, but we
  59    have to work with 2.9.1.  Note that N_SHARED_LIB is used in a
  60    SUN-specific context, not applicable to CRIS.  */
  61 #define N_SHARED_LIB(x) 0
  62
  63 /* The definition here seems not used; just provided as a convention.  */
  64 #define DEFAULT_ARCH bfd_arch_cris
  65
  66 /* Do not "beautify" the CONCAT* macro args.  Traditional C will not
  67    remove whitespace added here, and thus will fail to concatenate
  68    the tokens.  */
  69 #define MY(OP) CONCAT2 (cris_aout_,OP)
  70 #define NAME(x, y) CONCAT3 (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 bfd_boolean MY (write_object_contents) (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) (bfd *, arelent *, struct reloc_ext_external *);
  85
  86 #define MY_swap_ext_reloc_in MY (swap_ext_reloc_in)
  87 static void MY (swap_ext_reloc_in) (bfd *, struct reloc_ext_external *,
  88                                     arelent *, asymbol **, bfd_size_type);
  89
  90 #define MY_set_sizes MY (set_sizes)
  91 static bfd_boolean MY (set_sizes) (bfd *);
  92
  93 /* To set back reloc_size to ext, we make MY (set_sizes) be called
  94    through this construct.  Note that MY_set_arch_mach is only called
  95    through SET_ARCH_MACH.  The default bfd_default_set_arch_mach will
  96    not call set_sizes.  */
  97
  98 #define MY_set_arch_mach NAME (aout, set_arch_mach)
  99 #define SET_ARCH_MACH(BFD, EXEC) \
 100  MY_set_arch_mach (BFD, DEFAULT_ARCH, N_MACHTYPE (EXEC))
 101
 102 /* These macros describe the binary layout of the reloc information we
 103    use in a file.  */
 104 #define RELOC_EXT_BITS_EXTERN_LITTLE  0x80
 105 #define RELOC_EXT_BITS_TYPE_LITTLE    3
 106 #define RELOC_EXT_BITS_TYPE_SH_LITTLE 0
 107
 108 #ifndef MY_get_section_contents
 109 #define MY_get_section_contents aout_32_get_section_contents
 110 #endif
 111
 112 #define MACHTYPE_OK(mtype) ((mtype) == M_CRIS)
 113
 114 /* Include generic functions (some are overridden above).  */
 115 #include "aout32.c"
 116 #include "aout-target.h"
 117
 118 /* We need our own version to set header flags.  */
 119
 120 static bfd_boolean
 121 MY (write_object_contents) (bfd *abfd)
 122 {
 123   struct external_exec exec_bytes;
 124   struct internal_exec *execp = exec_hdr (abfd);
 125
 126   /* We set the reloc type to RELOC_EXT_SIZE, although setting it at all
 127      seems unnecessary when inspecting as and ld behavior (not an
 128      exhaustive inspection).  The default write_object_contents
 129      definition sets RELOC_EXT_SIZE, so we follow suite and set it too.  */
 130   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 131
 132   /* Setting N_SET_MACHTYPE and using N_SET_FLAGS is not performed by
 133      the default definition.  */
 134   if (bfd_get_arch (abfd) == bfd_arch_cris)
 135     N_SET_MACHTYPE (*execp, M_CRIS);
 136
 137   N_SET_FLAGS (*execp, aout_backend_info (abfd)->exec_hdr_flags);
 138
 139   WRITE_HEADERS (abfd, execp);
 140
 141   return TRUE;
 142 }
 143
 144 /* We need our own for these reasons:
 145    - Assert that a normal 8, 16 or 32 reloc is output.
 146    - Fix what seems to be a weak-bug (perhaps there for valid reasons).  */
 147
 148 static void
 149 MY (swap_ext_reloc_out) (bfd *abfd,
 150                          arelent *g,
 151                          struct reloc_ext_external *natptr)
 152 {
 153   int r_index;
 154   int r_extern;
 155   unsigned int r_type;
 156   bfd_vma r_addend;
 157   asymbol *sym = *(g->sym_ptr_ptr);
 158   asection *output_section = sym->section->output_section;
 159
 160   PUT_WORD (abfd, g->address, natptr->r_address);
 161
 162   r_type = (unsigned int) g->howto->type;
 163
 164   r_addend = g->addend;
 165   if ((sym->flags & BSF_SECTION_SYM) != 0)
 166     r_addend += (*(g->sym_ptr_ptr))->section->output_section->vma;
 167
 168   /* If this relocation is relative to a symbol then set the
 169      r_index to the symbols index, and the r_extern bit.
 170
 171      Absolute symbols can come in in two ways, either as an offset
 172      from the abs section, or as a symbol which has an abs value.
 173      check for that here.  */
 174
 175   if (bfd_is_abs_section (bfd_get_section (sym)))
 176     {
 177       r_extern = 0;
 178       r_index = N_ABS;
 179     }
 180   else if ((sym->flags & BSF_SECTION_SYM) == 0)
 181     {
 182       if (bfd_is_und_section (bfd_get_section (sym))
 183           /* Remember to check for weak symbols; they count as global.  */
 184           || (sym->flags & (BSF_GLOBAL | BSF_WEAK)) != 0)
 185         r_extern = 1;
 186       else
 187         r_extern = 0;
 188       r_index = (*(g->sym_ptr_ptr))->KEEPIT;
 189     }
 190   else
 191     {
 192       /* Just an ordinary section.  */
 193       r_extern = 0;
 194       r_index = output_section->target_index;
 195     }
 196
 197   /* The relocation type is the same as the canonical ones, but only
 198      the first 3 are used: RELOC_8, RELOC_16, RELOC_32.
 199      We may change this later, but assert this for the moment.  */
 200   if (r_type > 2)
 201     {
 202       (*_bfd_error_handler) (_("%s: Invalid relocation type exported: %d"),
 203                              bfd_get_filename (abfd), r_type);
 204
 205       bfd_set_error (bfd_error_wrong_format);
 206     }
 207
 208   /* Now the fun stuff.  */
 209   natptr->r_index[2] = r_index >> 16;
 210   natptr->r_index[1] = r_index >> 8;
 211   natptr->r_index[0] = r_index;
 212   natptr->r_type[0] =
 213      (r_extern ? RELOC_EXT_BITS_EXTERN_LITTLE : 0)
 214       | (r_type << RELOC_EXT_BITS_TYPE_SH_LITTLE);
 215
 216   PUT_WORD (abfd, r_addend, natptr->r_addend);
 217 }
 218
 219 /* We need our own to assert that a normal 8, 16 or 32 reloc is input.  */
 220
 221 static void
 222 MY (swap_ext_reloc_in) (bfd *abfd,
 223                         struct reloc_ext_external *bytes,
 224                         arelent *cache_ptr,
 225                         asymbol **symbols,
 226                         bfd_size_type symcount)
 227 {
 228   unsigned int r_index;
 229   int r_extern;
 230   unsigned int r_type;
 231   struct aoutdata *su = &(abfd->tdata.aout_data->a);
 232
 233   cache_ptr->address = (GET_SWORD (abfd, bytes->r_address));
 234
 235   /* Now the fun stuff.  */
 236   r_index =  (bytes->r_index[2] << 16)
 237     | (bytes->r_index[1] << 8)
 238     |  bytes->r_index[0];
 239   r_extern = (0 != (bytes->r_type[0] & RELOC_EXT_BITS_EXTERN_LITTLE));
 240   r_type = ((bytes->r_type[0]) >> RELOC_EXT_BITS_TYPE_SH_LITTLE)
 241     & RELOC_EXT_BITS_TYPE_LITTLE;
 242
 243   if (r_type > 2)
 244     {
 245       (*_bfd_error_handler) (_("%B: Invalid relocation type imported: %d"),
 246                              abfd, r_type);
 247
 248       bfd_set_error (bfd_error_wrong_format);
 249     }
 250
 251   cache_ptr->howto =  howto_table_ext + r_type;
 252
 253   if (r_extern && r_index > symcount)
 254     {
 255       (*_bfd_error_handler)
 256         (_("%B: Bad relocation record imported: %d"), abfd, r_index);
 257
 258       bfd_set_error (bfd_error_wrong_format);
 259
 260       /* We continue, so we can catch further errors.  */
 261       r_extern = 0;
 262       r_index = N_ABS;
 263     }
 264
 265   /* Magically uses r_extern, symbols etc.  Ugly, but it's what's in the
 266      default.  */
 267   MOVE_ADDRESS (GET_SWORD (abfd, bytes->r_addend));
 268 }
 269
 270 /* We use the same as the default, except that we also set
 271    "obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;", to avoid changing
 272    NAME (aout, set_arch_mach) in aoutx.  */
 273
 274 static bfd_boolean
 275 MY (set_sizes) (bfd *abfd)
 276 {
 277   /* Just as the default in aout-target.h (with some #ifdefs folded)...  */
 278
 279   adata (abfd).page_size = TARGET_PAGE_SIZE;
 280   adata (abfd).segment_size = SEGMENT_SIZE;
 281   adata (abfd).zmagic_disk_block_size = ZMAGIC_DISK_BLOCK_SIZE;
 282   adata (abfd).exec_bytes_size = EXEC_BYTES_SIZE;
 283
 284   /* ... except for that we have the extended reloc.  The alternative
 285      would be to add a check on bfd_arch_cris in NAME (aout,
 286      set_arch_mach) in aoutx.h, but I don't want to do that since
 287      target-specific things should not be added there.  */
 288
 289   obj_reloc_entry_size (abfd) = RELOC_EXT_SIZE;
 290
 291   return TRUE;
 292 }