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, 2007 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 3 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, 21 MA 02110-1301, USA. */ 22 23 24 /* Most of this hacked by Steve Chamberlain <sac@cygnus.com>. */ 25 26 /* These routines are used by coff-h8300 and coff-z8k to do 27 relocation. 28 29 FIXME: This code should be rewritten to support the new COFF 30 linker. Basically, they need to deal with COFF relocs rather than 31 BFD generic relocs. They should store the relocs in some location 32 where coff_link_input_bfd can find them (and coff_link_input_bfd 33 should be changed to use this location rather than rereading the 34 file) (unless info->keep_memory is FALSE, in which case they should 35 free up the relocs after dealing with them). */ 36 37 #include "sysdep.h" 38 #include "bfd.h" 39 #include "libbfd.h" 40 #include "bfdlink.h" 41 #include "genlink.h" 42 #include "coff/internal.h" 43 #include "libcoff.h" 44 45 bfd_vma 46 bfd_coff_reloc16_get_value (reloc, link_info, input_section) 47 arelent *reloc; 48 struct bfd_link_info *link_info; 49 asection *input_section; 50 { 51 bfd_vma value; 52 asymbol *symbol = *(reloc->sym_ptr_ptr); 53 /* A symbol holds a pointer to a section, and an offset from the 54 base of the section. To relocate, we find where the section will 55 live in the output and add that in. */ 56 57 if (bfd_is_und_section (symbol->section) 58 || bfd_is_com_section (symbol->section)) 59 { 60 struct bfd_link_hash_entry *h; 61 62 /* The symbol is undefined in this BFD. Look it up in the 63 global linker hash table. FIXME: This should be changed when 64 we convert this stuff to use a specific final_link function 65 and change the interface to bfd_relax_section to not require 66 the generic symbols. */ 67 h = bfd_wrapped_link_hash_lookup (input_section->owner, link_info, 68 bfd_asymbol_name (symbol), 69 FALSE, FALSE, TRUE); 70 if (h != (struct bfd_link_hash_entry *) NULL 71 && (h->type == bfd_link_hash_defined 72 || h->type == bfd_link_hash_defweak)) 73 value = (h->u.def.value 74 + h->u.def.section->output_section->vma 75 + h->u.def.section->output_offset); 76 else if (h != (struct bfd_link_hash_entry *) NULL 77 && h->type == bfd_link_hash_common) 78 value = h->u.c.size; 79 else if (h != (struct bfd_link_hash_entry *) NULL 80 && h->type == bfd_link_hash_undefweak) 81 /* This is a GNU extension. */ 82 value = 0; 83 else 84 { 85 if (!((*link_info->callbacks->undefined_symbol) 86 (link_info, bfd_asymbol_name (symbol), 87 input_section->owner, input_section, reloc->address, 88 TRUE))) 89 abort (); 90 value = 0; 91 } 92 } 93 else 94 { 95 value = symbol->value 96 + symbol->section->output_offset 97 + symbol->section->output_section->vma; 98 } 99 100 /* Add the value contained in the relocation. */ 101 value += reloc->addend; 102 103 return value; 104 } 105 106 void 107 bfd_perform_slip (abfd, slip, input_section, value) 108 bfd *abfd; 109 unsigned int slip; 110 asection *input_section; 111 bfd_vma value; 112 { 113 asymbol **s; 114 115 s = _bfd_generic_link_get_symbols (abfd); 116 BFD_ASSERT (s != (asymbol **) NULL); 117 118 /* Find all symbols past this point, and make them know 119 what's happened. */ 120 while (*s) 121 { 122 asymbol *p = *s; 123 if (p->section == input_section) 124 { 125 /* This was pointing into this section, so mangle it. */ 126 if (p->value > value) 127 { 128 p->value -= slip; 129 if (p->udata.p != NULL) 130 { 131 struct generic_link_hash_entry *h; 132 133 h = (struct generic_link_hash_entry *) p->udata.p; 134 BFD_ASSERT (h->root.type == bfd_link_hash_defined 135 || h->root.type == bfd_link_hash_defweak); 136 h->root.u.def.value -= slip; 137 BFD_ASSERT (h->root.u.def.value == p->value); 138 } 139 } 140 } 141 s++; 142 } 143 } 144 145 bfd_boolean 146 bfd_coff_reloc16_relax_section (abfd, input_section, link_info, again) 147 bfd *abfd; 148 asection *input_section; 149 struct bfd_link_info *link_info; 150 bfd_boolean *again; 151 { 152 /* Get enough memory to hold the stuff. */ 153 bfd *input_bfd = input_section->owner; 154 unsigned *shrinks; 155 unsigned shrink = 0; 156 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section); 157 arelent **reloc_vector = NULL; 158 long reloc_count; 159 160 /* We only do global relaxation once. It is not safe to do it multiple 161 times (see discussion of the "shrinks" array below). */ 162 *again = FALSE; 163 164 if (reloc_size < 0) 165 return FALSE; 166 167 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size); 168 if (!reloc_vector && reloc_size > 0) 169 return FALSE; 170 171 /* Get the relocs and think about them. */ 172 reloc_count = 173 bfd_canonicalize_reloc (input_bfd, input_section, reloc_vector, 174 _bfd_generic_link_get_symbols (input_bfd)); 175 if (reloc_count < 0) 176 { 177 free (reloc_vector); 178 return FALSE; 179 } 180 181 /* The reloc16.c and related relaxing code is very simple, the price 182 for that simplicity is we can only call this function once for 183 each section. 184 185 So, to get the best results within that limitation, we do multiple 186 relaxing passes over each section here. That involves keeping track 187 of the "shrink" at each reloc in the section. This allows us to 188 accurately determine the relative location of two relocs within 189 this section. 190 191 In theory, if we kept the "shrinks" array for each section for the 192 entire link, we could use the generic relaxing code in the linker 193 and get better results, particularly for jsr->bsr and 24->16 bit 194 memory reference relaxations. */ 195 196 if (reloc_count > 0) 197 { 198 int another_pass = 0; 199 bfd_size_type amt; 200 201 /* Allocate and initialize the shrinks array for this section. 202 The last element is used as an accumulator of shrinks. */ 203 amt = reloc_count + 1; 204 amt *= sizeof (unsigned); 205 shrinks = (unsigned *) bfd_zmalloc (amt); 206 207 /* Loop until nothing changes in this section. */ 208 do 209 { 210 arelent **parent; 211 unsigned int i; 212 long j; 213 214 another_pass = 0; 215 216 for (i = 0, parent = reloc_vector; *parent; parent++, i++) 217 { 218 /* Let the target/machine dependent code examine each reloc 219 in this section and attempt to shrink it. */ 220 shrink = bfd_coff_reloc16_estimate (abfd, input_section, *parent, 221 shrinks[i], link_info); 222 223 /* If it shrunk, note it in the shrinks array and set up for 224 another pass. */ 225 if (shrink != shrinks[i]) 226 { 227 another_pass = 1; 228 for (j = i + 1; j <= reloc_count; j++) 229 shrinks[j] += shrink - shrinks[i]; 230 } 231 } 232 } 233 while (another_pass); 234 235 shrink = shrinks[reloc_count]; 236 free ((char *) shrinks); 237 } 238 239 input_section->rawsize = input_section->size; 240 input_section->size -= shrink; 241 free ((char *) reloc_vector); 242 return TRUE; 243 } 244 245 bfd_byte * 246 bfd_coff_reloc16_get_relocated_section_contents (in_abfd, 247 link_info, 248 link_order, 249 data, 250 relocatable, 251 symbols) 252 bfd *in_abfd; 253 struct bfd_link_info *link_info; 254 struct bfd_link_order *link_order; 255 bfd_byte *data; 256 bfd_boolean relocatable; 257 asymbol **symbols; 258 { 259 /* Get enough memory to hold the stuff. */ 260 bfd *input_bfd = link_order->u.indirect.section->owner; 261 asection *input_section = link_order->u.indirect.section; 262 long reloc_size = bfd_get_reloc_upper_bound (input_bfd, input_section); 263 arelent **reloc_vector; 264 long reloc_count; 265 bfd_size_type sz; 266 267 if (reloc_size < 0) 268 return NULL; 269 270 /* If producing relocatable output, don't bother to relax. */ 271 if (relocatable) 272 return bfd_generic_get_relocated_section_contents (in_abfd, link_info, 273 link_order, 274 data, relocatable, 275 symbols); 276 277 /* Read in the section. */ 278 sz = input_section->rawsize ? input_section->rawsize : input_section->size; 279 if (!bfd_get_section_contents (input_bfd, input_section, data, 0, sz)) 280 return NULL; 281 282 reloc_vector = (arelent **) bfd_malloc ((bfd_size_type) reloc_size); 283 if (!reloc_vector && reloc_size != 0) 284 return NULL; 285 286 reloc_count = bfd_canonicalize_reloc (input_bfd, 287 input_section, 288 reloc_vector, 289 symbols); 290 if (reloc_count < 0) 291 { 292 free (reloc_vector); 293 return NULL; 294 } 295 296 if (reloc_count > 0) 297 { 298 arelent **parent = reloc_vector; 299 arelent *reloc; 300 unsigned int dst_address = 0; 301 unsigned int src_address = 0; 302 unsigned int run; 303 unsigned int idx; 304 305 /* Find how long a run we can do. */ 306 while (dst_address < link_order->size) 307 { 308 reloc = *parent; 309 if (reloc) 310 { 311 /* Note that the relaxing didn't tie up the addresses in the 312 relocation, so we use the original address to work out the 313 run of non-relocated data. */ 314 run = reloc->address - src_address; 315 parent++; 316 } 317 else 318 { 319 run = link_order->size - dst_address; 320 } 321 322 /* Copy the bytes. */ 323 for (idx = 0; idx < run; idx++) 324 data[dst_address++] = data[src_address++]; 325 326 /* Now do the relocation. */ 327 if (reloc) 328 { 329 bfd_coff_reloc16_extra_cases (input_bfd, link_info, link_order, 330 reloc, data, &src_address, 331 &dst_address); 332 } 333 } 334 } 335 free ((char *) reloc_vector); 336 return data; 337 } 338