| 1 | /* 8 and 16 bit COFF relocation functions, for BFD. |
| 2 | Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 2000, 2001, |
| 3 | 2002, 2003, 2004 Free Software Foundation, Inc. |
| 4 | Written by Cygnus Support. |
| 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 | /* Most of this hacked by Steve Chamberlain <sac@cygnus.com>. */ |
| 23 | |
| 24 | /* These routines are used by coff-h8300 and coff-z8k to do |
| 25 | relocation. |
| 26 | |
| 27 | FIXME: This code should be rewritten to support the new COFF |
| 28 | linker. Basically, they need to deal with COFF relocs rather than |
| 29 | BFD generic relocs. They should store the relocs in some location |
| 30 | where coff_link_input_bfd can find them (and coff_link_input_bfd |
| 31 | should be changed to use this location rather than rereading the |
| 32 | file) (unless info->keep_memory is FALSE, in which case they should |
| 33 | free up the relocs after dealing with them). */ |
| 34 | |
| 35 | #include "bfd.h" |
| 36 | #include "sysdep.h" |
| 37 | #include "libbfd.h" |
| 38 | #include "bfdlink.h" |
| 39 | #include "genlink.h" |
| 40 | #include "coff/internal.h" |
| 41 | #include "libcoff.h" |
| 42 | |
| 43 | bfd_vma |
| 44 | bfd_coff_reloc16_get_value (reloc, link_info, input_section) |
| 45 | arelent *reloc; |
| 46 | struct bfd_link_info *link_info; |
| 47 | asection *input_section; |
| 48 | { |
| 49 | bfd_vma value; |
| 50 | asymbol *symbol = *(reloc->sym_ptr_ptr); |
| 51 | /* A symbol holds a pointer to a section, and an offset from the |
| 52 | base of the section. To relocate, we find where the section will |
| 53 | live in the output and add that in. */ |
| 54 | |
| 55 | if (bfd_is_und_section (symbol->section) |
| 56 | || bfd_is_com_section (symbol->section)) |
| 57 | { |
| 58 | struct bfd_link_hash_entry *h; |
| 59 | |
| 60 | /* The symbol is undefined in this BFD. Look it up in the |
| 61 | global linker hash table. FIXME: This should be changed when |
| 62 | we convert this stuff to use a specific final_link function |
| 63 | and change the interface to bfd_relax_section to not require |
| 64 | the generic symbols. */ |
| 65 | h = bfd_wrapped_link_hash_lookup (input_section->owner, link_info, |
| 66 | bfd_asymbol_name (symbol), |
| 67 | FALSE, FALSE, TRUE); |
| 68 | if (h != (struct bfd_link_hash_entry *) NULL |
| 69 | && (h->type == bfd_link_hash_defined |
| 70 | || h->type == bfd_link_hash_defweak)) |
| 71 | value = (h->u.def.value |
| 72 | + h->u.def.section->output_section->vma |
| 73 | + h->u.def.section->output_offset); |
| 74 | else if (h != (struct bfd_link_hash_entry *) NULL |
| 75 | && h->type == bfd_link_hash_common) |
| 76 | value = h->u.c.size; |
| 77 | else |
| 78 | { |
| 79 | if (!((*link_info->callbacks->undefined_symbol) |
| 80 | (link_info, bfd_asymbol_name (symbol), |
| 81 | input_section->owner, input_section, reloc->address, |
| 82 | TRUE))) |
| 83 | abort (); |
| 84 | value = 0; |
| 85 | } |
| 86 | } |
| 87 | else |
| 88 | { |
| 89 | value = symbol->value |
| 90 | + symbol->section->output_offset |
| 91 | + symbol->section->output_section->vma; |
| 92 | } |
| 93 | |
| 94 | /* Add the value contained in the relocation. */ |
| 95 | value += reloc->addend; |
| 96 | |
| 97 | return value; |
| 98 | } |
| 99 | |
| 100 | void |
| 101 | bfd_perform_slip (abfd, slip, input_section, value) |
| 102 | bfd *abfd; |
| 103 | unsigned int slip; |
| 104 | asection *input_section; |
| 105 | bfd_vma value; |
| 106 | { |
| 107 | asymbol **s; |
| 108 | |
| 109 | s = _bfd_generic_link_get_symbols (abfd); |
| 110 | BFD_ASSERT (s != (asymbol **) NULL); |
| 111 | |
| 112 | /* Find all symbols past this point, and make them know |
| 113 | what's happened. */ |
| 114 | while (*s) |
| 115 | { |
| 116 | asymbol *p = *s; |
| 117 | if (p->section == input_section) |
| 118 | { |
| 119 | /* This was pointing into this section, so mangle it. */ |
| 120 | if (p->value > value) |
| 121 | { |
| 122 | p->value -= slip; |
| 123 | if (p->udata.p != NULL) |
| 124 | { |
| 125 | struct generic_link_hash_entry *h; |
| 126 | |
| 127 | h = (struct generic_link_hash_entry *) p->udata.p; |
| 128 | BFD_ASSERT (h->root.type == bfd_link_hash_defined |
| 129 | || h->root.type == bfd_link_hash_defweak); |
| 130 | h->root.u.def.value -= slip; |
| 131 | BFD_ASSERT (h->root.u.def.value == p->value); |
| 132 | } |
| 133 | } |
| 134 | } |
| 135 | s++; |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | bfd_boolean |
| 140 | bfd_coff_reloc16_relax_section (abfd, input_section, link_info, again) |
| 141 | bfd *abfd; |
| 142 | asection *input_section; |
| 143 | struct bfd_link_info *link_info; |
| 144 | bfd_boolean *again; |
| 145 | { |
| 146 | /* Get enough memory to hold the stuff. */ |
| 147 | bfd *input_bfd = input_section->owner; |
| 148 | unsigned *shrinks; |
| 149 | unsigned shrink = 0; |
| 150 | long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section); |
| 151 | arelent **reloc_vector = NULL; |
| 152 | long reloc_count; |
| 153 | |
| 154 | /* We only do global relaxation once. It is not safe to do it multiple |
| 155 | times (see discussion of the "shrinks" array below). */ |
| 156 | *again = FALSE; |
| 157 | |
| 158 | if (reloc_size < 0) |
| 159 | return FALSE; |
| 160 | |
| 161 | reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size); |
| 162 | if (!reloc_vector && reloc_size > 0) |
| 163 | return FALSE; |
| 164 | |
| 165 | /* Get the relocs and think about them. */ |
| 166 | reloc_count = |
| 167 | bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector, |
| 168 | _bfd_generic_link_get_symbols (input_bfd)); |
| 169 | if (reloc_count < 0) |
| 170 | { |
| 171 | free (reloc_vector); |
| 172 | return FALSE; |
| 173 | } |
| 174 | |
| 175 | /* The reloc16.c and related relaxing code is very simple, the price |
| 176 | for that simplicity is we can only call this function once for |
| 177 | each section. |
| 178 | |
| 179 | So, to get the best results within that limitation, we do multiple |
| 180 | relaxing passes over each section here. That involves keeping track |
| 181 | of the "shrink" at each reloc in the section. This allows us to |
| 182 | accurately determine the relative location of two relocs within |
| 183 | this section. |
| 184 | |
| 185 | In theory, if we kept the "shrinks" array for each section for the |
| 186 | entire link, we could use the generic relaxing code in the linker |
| 187 | and get better results, particularly for jsr->bsr and 24->16 bit |
| 188 | memory reference relaxations. */ |
| 189 | |
| 190 | if (reloc_count > 0) |
| 191 | { |
| 192 | int another_pass = 0; |
| 193 | bfd_size_type amt; |
| 194 | |
| 195 | /* Allocate and initialize the shrinks array for this section. |
| 196 | The last element is used as an accumulator of shrinks. */ |
| 197 | amt = reloc_count + 1; |
| 198 | amt *= sizeof (unsigned); |
| 199 | shrinks = (unsigned *) bfd_zmalloc (amt); |
| 200 | |
| 201 | /* Loop until nothing changes in this section. */ |
| 202 | do |
| 203 | { |
| 204 | arelent **parent; |
| 205 | unsigned int i; |
| 206 | long j; |
| 207 | |
| 208 | another_pass = 0; |
| 209 | |
| 210 | for (i = 0, parent = reloc_vector; *parent; parent++, i++) |
| 211 | { |
| 212 | /* Let the target/machine dependent code examine each reloc |
| 213 | in this section and attempt to shrink it. */ |
| 214 | shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent, |
| 215 | shrinks[i], link_info); |
| 216 | |
| 217 | /* If it shrunk, note it in the shrinks array and set up for |
| 218 | another pass. */ |
| 219 | if (shrink != shrinks[i]) |
| 220 | { |
| 221 | another_pass = 1; |
| 222 | for (j = i + 1; j <= reloc_count; j++) |
| 223 | shrinks[j] += shrink - shrinks[i]; |
| 224 | } |
| 225 | } |
| 226 | } |
| 227 | while (another_pass); |
| 228 | |
| 229 | shrink = shrinks[reloc_count]; |
| 230 | free ((char *) shrinks); |
| 231 | } |
| 232 | |
| 233 | input_section->rawsize = input_section->size; |
| 234 | input_section->size -= shrink; |
| 235 | free ((char *) reloc_vector); |
| 236 | return TRUE; |
| 237 | } |
| 238 | |
| 239 | bfd_byte * |
| 240 | bfd_coff_reloc16_get_relocated_section_contents (in_abfd, |
| 241 | link_info, |
| 242 | link_order, |
| 243 | data, |
| 244 | relocatable, |
| 245 | symbols) |
| 246 | bfd *in_abfd; |
| 247 | struct bfd_link_info *link_info; |
| 248 | struct bfd_link_order *link_order; |
| 249 | bfd_byte *data; |
| 250 | bfd_boolean relocatable; |
| 251 | asymbol **symbols; |
| 252 | { |
| 253 | /* Get enough memory to hold the stuff. */ |
| 254 | bfd *input_bfd = link_order->u.indirect.section->owner; |
| 255 | asection *input_section = link_order->u.indirect.section; |
| 256 | long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section); |
| 257 | arelent **reloc_vector; |
| 258 | long reloc_count; |
| 259 | bfd_size_type sz; |
| 260 | |
| 261 | if (reloc_size < 0) |
| 262 | return NULL; |
| 263 | |
| 264 | /* If producing relocatable output, don't bother to relax. */ |
| 265 | if (relocatable) |
| 266 | return bfd_generic_get_relocated_section_contents (in_abfd, link_info, |
| 267 | link_order, |
| 268 | data, relocatable, |
| 269 | symbols); |
| 270 | |
| 271 | /* Read in the section. */ |
| 272 | sz = input_section->rawsize ? input_section->rawsize : input_section->size; |
| 273 | if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz)) |
| 274 | return NULL; |
| 275 | |
| 276 | reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size); |
| 277 | if (!reloc_vector && reloc_size != 0) |
| 278 | return NULL; |
| 279 | |
| 280 | reloc_count = bfd_canonicalize_reloc (input_bfd, |
| 281 | input_section, |
| 282 | reloc_vector, |
| 283 | symbols); |
| 284 | if (reloc_count < 0) |
| 285 | { |
| 286 | free (reloc_vector); |
| 287 | return NULL; |
| 288 | } |
| 289 | |
| 290 | if (reloc_count > 0) |
| 291 | { |
| 292 | arelent **parent = reloc_vector; |
| 293 | arelent *reloc; |
| 294 | unsigned int dst_address = 0; |
| 295 | unsigned int src_address = 0; |
| 296 | unsigned int run; |
| 297 | unsigned int idx; |
| 298 | |
| 299 | /* Find how long a run we can do. */ |
| 300 | while (dst_address < link_order->size) |
| 301 | { |
| 302 | reloc = *parent; |
| 303 | if (reloc) |
| 304 | { |
| 305 | /* Note that the relaxing didn't tie up the addresses in the |
| 306 | relocation, so we use the original address to work out the |
| 307 | run of non-relocated data. */ |
| 308 | run = reloc->address - src_address; |
| 309 | parent++; |
| 310 | } |
| 311 | else |
| 312 | { |
| 313 | run = link_order->size - dst_address; |
| 314 | } |
| 315 | |
| 316 | /* Copy the bytes. */ |
| 317 | for (idx = 0; idx < run; idx++) |
| 318 | data[dst_address++] = data[src_address++]; |
| 319 | |
| 320 | /* Now do the relocation. */ |
| 321 | if (reloc) |
| 322 | { |
| 323 | bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order, |
| 324 | reloc, data, &src_address, |
| 325 | &dst_address); |
| 326 | } |
| 327 | } |
| 328 | } |
| 329 | free ((char *) reloc_vector); |
| 330 | return data; |
| 331 | } |