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., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, 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 } 332