ld/emultempl/elf32.em

   1 # This shell script emits a C file. -*- C -*-
   2 # It does some substitutions.
   3 cat >e${EMULATION_NAME}.c <<EOF
   4 /* This file is is generated by a shell script.  DO NOT EDIT! */
   5
   6 /* 32 bit ELF emulation code for ${EMULATION_NAME}
   7    Copyright (C) 1991, 1993, 1994, 1995 Free Software Foundation, Inc.
   8    Written by Steve Chamberlain <sac@cygnus.com>
   9    ELF support by Ian Lance Taylor <ian@cygnus.com>
  10
  11 This file is part of GLD, the Gnu Linker.
  12
  13 This program is free software; you can redistribute it and/or modify
  14 it under the terms of the GNU General Public License as published by
  15 the Free Software Foundation; either version 2 of the License, or
  16 (at your option) any later version.
  17
  18 This program is distributed in the hope that it will be useful,
  19 but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 GNU General Public License for more details.
  22
  23 You should have received a copy of the GNU General Public License
  24 along with this program; if not, write to the Free Software
  25 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
  26
  27 #define TARGET_IS_${EMULATION_NAME}
  28
  29 #include "bfd.h"
  30 #include "sysdep.h"
  31
  32 #include <ctype.h>
  33
  34 #include "bfdlink.h"
  35
  36 #include "ld.h"
  37 #include "config.h"
  38 #include "ldmain.h"
  39 #include "ldemul.h"
  40 #include "ldfile.h"
  41 #include "ldmisc.h"
  42 #include "ldexp.h"
  43 #include "ldlang.h"
  44 #include "ldgram.h"
  45
  46 static void gld${EMULATION_NAME}_before_parse PARAMS ((void));
  47 static boolean gld${EMULATION_NAME}_open_dynamic_archive
  48   PARAMS ((const char *, lang_input_statement_type *));
  49 static void gld${EMULATION_NAME}_before_allocation PARAMS ((void));
  50 static void gld${EMULATION_NAME}_find_statement_assignment
  51   PARAMS ((lang_statement_union_type *));
  52 static void gld${EMULATION_NAME}_find_exp_assignment PARAMS ((etree_type *));
  53 static boolean gld${EMULATION_NAME}_place_orphan
  54   PARAMS ((lang_input_statement_type *, asection *));
  55 static void gld${EMULATION_NAME}_place_section
  56   PARAMS ((lang_statement_union_type *));
  57 static char *gld${EMULATION_NAME}_get_script PARAMS ((int *isfile));
  58
  59 static void
  60 gld${EMULATION_NAME}_before_parse()
  61 {
  62   ldfile_output_architecture = bfd_arch_${ARCH};
  63   config.dynamic_link = ${DYNAMIC_LINK-true};
  64 }
  65
  66 /* Try to open a dynamic archive.  This is where we know that ELF
  67    dynamic libraries have an extension of .so.  */
  68
  69 static boolean
  70 gld${EMULATION_NAME}_open_dynamic_archive (arch, entry)
  71      const char *arch;
  72      lang_input_statement_type *entry;
  73 {
  74   const char *filename;
  75
  76   filename = entry->filename;
  77
  78   if (! ldfile_open_file_search (arch, entry, "lib", ".so"))
  79     return false;
  80
  81   /* We have found a dynamic object to include in the link.  The ELF
  82      backend linker will create a DT_NEEDED entry in the .dynamic
  83      section naming this file.  If this file includes a DT_SONAME
  84      entry, it will be used.  Otherwise, the ELF linker will just use
  85      the name of the file.  For an archive found by searching, like
  86      this one, the DT_NEEDED entry should consist of just the name of
  87      the file, without the path information used to find it.  Note
  88      that we only need to do this if we have a dynamic object; an
  89      archive will never be referenced by a DT_NEEDED entry.
  90
  91      FIXME: This approach--using bfd_elf_set_dt_needed_name--is not
  92      very pretty.  I haven't been able to think of anything that is
  93      pretty, though.  */
  94   if (bfd_check_format (entry->the_bfd, bfd_object)
  95       && (entry->the_bfd->flags & DYNAMIC) != 0)
  96     {
  97       char *needed_name;
  98
  99       ASSERT (entry->is_archive && entry->search_dirs_flag);
 100       needed_name = (char *) xmalloc (strlen (filename)
 101                                       + strlen (arch)
 102                                       + sizeof "lib.so");
 103       sprintf (needed_name, "lib%s%s.so", filename, arch);
 104       bfd_elf_set_dt_needed_name (entry->the_bfd, needed_name);
 105     }
 106
 107   return true;
 108 }
 109
 110 /* This is called after the sections have been attached to output
 111    sections, but before any sizes or addresses have been set.  */
 112
 113 static void
 114 gld${EMULATION_NAME}_before_allocation ()
 115 {
 116   asection *sinterp;
 117   lang_input_statement_type *is;
 118
 119   /* If we are going to make any variable assignments, we need to let
 120      the ELF backend know about them in case the variables are
 121      referred to by dynamic objects.  */
 122   lang_for_each_statement (gld${EMULATION_NAME}_find_statement_assignment);
 123
 124   /* Let the ELF backend work out the sizes of any sections required
 125      by dynamic linking.  */
 126   if (! bfd_elf32_size_dynamic_sections (output_bfd,
 127                                          command_line.soname,
 128                                          command_line.rpath,
 129                                          command_line.export_dynamic,
 130                                          &link_info,
 131                                          &sinterp))
 132     einfo ("%P%F: failed to set dynamic section sizes: %E\n");
 133
 134   /* Let the user override the dynamic linker we are using.  */
 135   if (command_line.interpreter != NULL
 136       && sinterp != NULL)
 137     {
 138       sinterp->contents = (bfd_byte *) command_line.interpreter;
 139       sinterp->_raw_size = strlen (command_line.interpreter) + 1;
 140     }
 141
 142   /* Look for any sections named .gnu.warning.  As a GNU extensions,
 143      we treat such sections as containing warning messages.  We print
 144      out the warning message, and then zero out the section size so
 145      that it does not get copied into the output file.  */
 146
 147   {
 148     LANG_FOR_EACH_INPUT_STATEMENT (is)
 149       {
 150         asection *s;
 151         bfd_size_type sz;
 152         char *msg;
 153         boolean ret;
 154
 155         if (is->just_syms_flag)
 156           continue;
 157
 158         s = bfd_get_section_by_name (is->the_bfd, ".gnu.warning");
 159         if (s == NULL)
 160           continue;
 161
 162         sz = bfd_section_size (is->the_bfd, s);
 163         msg = xmalloc ((size_t) sz + 1);
 164         if (! bfd_get_section_contents (is->the_bfd, s, msg, (file_ptr) 0, sz))
 165           einfo ("%F%B: Can't read contents of section .gnu.warning: %E\n",
 166                  is->the_bfd);
 167         msg[sz] = '\0';
 168         ret = link_info.callbacks->warning (&link_info, msg);
 169         ASSERT (ret);
 170         free (msg);
 171
 172         /* Clobber the section size, so that we don't waste copying the
 173            warning into the output file.  */
 174         s->_raw_size = 0;
 175       }
 176   }
 177 }
 178
 179 /* This is called by the before_allocation routine via
 180    lang_for_each_statement.  It locates any assignment statements, and
 181    tells the ELF backend about them, in case they are assignments to
 182    symbols which are referred to by dynamic objects.  */
 183
 184 static void
 185 gld${EMULATION_NAME}_find_statement_assignment (s)
 186      lang_statement_union_type *s;
 187 {
 188   if (s->header.type == lang_assignment_statement_enum)
 189     gld${EMULATION_NAME}_find_exp_assignment (s->assignment_statement.exp);
 190 }
 191
 192 /* Look through an expression for an assignment statement.  */
 193
 194 static void
 195 gld${EMULATION_NAME}_find_exp_assignment (exp)
 196      etree_type *exp;
 197 {
 198   switch (exp->type.node_class)
 199     {
 200     case etree_assign:
 201       if (strcmp (exp->assign.dst, ".") != 0)
 202         {
 203           if (! bfd_elf32_record_link_assignment (output_bfd, &link_info,
 204                                                   exp->assign.dst))
 205             einfo ("%P%F: failed to record assignment to %s: %E\n",
 206                    exp->assign.dst);
 207         }
 208       gld${EMULATION_NAME}_find_exp_assignment (exp->assign.src);
 209       break;
 210
 211     case etree_binary:
 212       gld${EMULATION_NAME}_find_exp_assignment (exp->binary.lhs);
 213       gld${EMULATION_NAME}_find_exp_assignment (exp->binary.rhs);
 214       break;
 215
 216     case etree_trinary:
 217       gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.lhs);
 218       gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.lhs);
 219       gld${EMULATION_NAME}_find_exp_assignment (exp->trinary.rhs);
 220       break;
 221
 222     case etree_unary:
 223       gld${EMULATION_NAME}_find_exp_assignment (exp->unary.child);
 224       break;
 225
 226     default:
 227       break;
 228     }
 229 }
 230
 231 /* Place an orphan section.  We use this to put random SHF_ALLOC
 232    sections in the right segment.  */
 233
 234 static asection *hold_section;
 235 static lang_output_section_statement_type *hold_use;
 236 static lang_output_section_statement_type *hold_text;
 237 static lang_output_section_statement_type *hold_data;
 238 static lang_output_section_statement_type *hold_bss;
 239
 240 /*ARGSUSED*/
 241 static boolean
 242 gld${EMULATION_NAME}_place_orphan (file, s)
 243      lang_input_statement_type *file;
 244      asection *s;
 245 {
 246   lang_output_section_statement_type *place;
 247   asection *snew, **pps;
 248   lang_statement_list_type *old;
 249   lang_statement_list_type add;
 250   etree_type *address;
 251   const char *secname, *ps;
 252   lang_output_section_statement_type *os;
 253
 254   if ((s->flags & SEC_ALLOC) == 0)
 255     return false;
 256
 257   /* Look through the script to see where to place this section.  */
 258   hold_section = s;
 259   hold_use = NULL;
 260   lang_for_each_statement (gld${EMULATION_NAME}_place_section);
 261
 262   if (hold_use != NULL)
 263     {
 264       /* We have already placed a section with this name.  */
 265       wild_doit (&hold_use->children, s, hold_use, file);
 266       return true;
 267     }
 268
 269   /* Decide which segment the section should go in based on the
 270      section flags.  */
 271   place = NULL;
 272   if ((s->flags & SEC_HAS_CONTENTS) == 0
 273       && hold_bss != NULL)
 274     place = hold_bss;
 275   else if ((s->flags & SEC_READONLY) == 0
 276            && hold_data != NULL)
 277     place = hold_data;
 278   else if ((s->flags & SEC_READONLY) != 0
 279            && hold_text != NULL)
 280     place = hold_text;
 281   if (place == NULL)
 282     return false;
 283
 284   secname = bfd_get_section_name (s->owner, s);
 285
 286   /* When generating an object which is to be dynamically linked, we
 287      do not support orphaned reloc sections.  This is because all the
 288      reloc sections must be contiguous in order to generate correct
 289      DT_REL entries.  When this case arises, you can just add the
 290      appropriate reloc sections to the linker script.  Note that the
 291      .rel.plt section must always be the last reloc section.  FIXME:
 292      This should simply be handled correctly here.  */
 293   ASSERT (strncmp (secname, ".rel", 4) != 0
 294           || bfd_get_section_by_name (output_bfd, ".dynamic") == NULL);
 295
 296   /* Create the section in the output file, and put it in the right
 297      place.  This shuffling to make the output file look neater, and
 298      also means that the BFD backend does not have to sort the
 299      sections in order by address.  */
 300   snew = bfd_make_section (output_bfd, secname);
 301   if (snew == NULL)
 302       einfo ("%P%F: output format %s cannot represent section called %s\n",
 303              output_bfd->xvec->name, secname);
 304   for (pps = &output_bfd->sections; *pps != snew; pps = &(*pps)->next)
 305     ;
 306   *pps = snew->next;
 307   snew->next = place->bfd_section->next;
 308   place->bfd_section->next = snew;
 309
 310   /* Start building a list of statements for this section.  */
 311   old = stat_ptr;
 312   stat_ptr = &add;
 313   lang_list_init (stat_ptr);
 314
 315   /* If the name of the section is representable in C, then create
 316      symbols to mark the start and the end of the section.  */
 317   for (ps = secname; *ps != '\0'; ps++)
 318     if (! isalnum (*ps) && *ps != '_')
 319       break;
 320   if (*ps == '\0' && config.build_constructors)
 321     {
 322       char *symname;
 323
 324       symname = (char *) xmalloc (ps - secname + sizeof "__start_");
 325       sprintf (symname, "__start_%s", secname);
 326       lang_add_assignment (exp_assop ('=', symname,
 327                                       exp_nameop (NAME, ".")));
 328     }
 329
 330   if (! link_info.relocateable)
 331     address = NULL;
 332   else
 333     address = exp_intop ((bfd_vma) 0);
 334
 335   lang_enter_output_section_statement (secname, address, 0,
 336                                        (bfd_vma) 0,
 337                                        (etree_type *) NULL,
 338                                        (etree_type *) NULL,
 339                                        (etree_type *) NULL);
 340
 341   os = lang_output_section_statement_lookup (secname);
 342   wild_doit (&os->children, s, os, file);
 343
 344   lang_leave_output_section_statement ((bfd_vma) 0, "*default*");
 345   stat_ptr = &add;
 346
 347   if (*ps == '\0' && config.build_constructors)
 348     {
 349       char *symname;
 350
 351       symname = (char *) xmalloc (ps - secname + sizeof "__stop_");
 352       sprintf (symname, "__stop_%s", secname);
 353       lang_add_assignment (exp_assop ('=', symname,
 354                                       exp_nameop (NAME, ".")));
 355     }
 356
 357   /* Now stick the new statement list right after PLACE.  */
 358   *add.tail = place->header.next;
 359   place->header.next = add.head;
 360
 361   stat_ptr = old;
 362
 363   return true;
 364 }
 365
 366 static void
 367 gld${EMULATION_NAME}_place_section (s)
 368      lang_statement_union_type *s;
 369 {
 370   lang_output_section_statement_type *os;
 371
 372   if (s->header.type != lang_output_section_statement_enum)
 373     return;
 374
 375   os = &s->output_section_statement;
 376
 377   if (strcmp (os->name, hold_section->name) == 0)
 378     hold_use = os;
 379
 380   if (strcmp (os->name, ".text") == 0)
 381     hold_text = os;
 382   else if (strcmp (os->name, ".data") == 0)
 383     hold_data = os;
 384   else if (strcmp (os->name, ".bss") == 0)
 385     hold_bss = os;
 386 }
 387
 388 static char *
 389 gld${EMULATION_NAME}_get_script(isfile)
 390      int *isfile;
 391 EOF
 392
 393 if test -n "$COMPILE_IN"
 394 then
 395 # Scripts compiled in.
 396
 397 # sed commands to quote an ld script as a C string.
 398 sc='s/["\\]/\\&/g
 399 s/$/\\n\\/
 400 1s/^/"/
 401 $s/$/n"/
 402 '
 403
 404 cat >>e${EMULATION_NAME}.c <<EOF
 405 {
 406   *isfile = 0;
 407
 408   if (link_info.relocateable == true && config.build_constructors == true)
 409     return `sed "$sc" ldscripts/${EMULATION_NAME}.xu`;
 410   else if (link_info.relocateable == true)
 411     return `sed "$sc" ldscripts/${EMULATION_NAME}.xr`;
 412   else if (!config.text_read_only)
 413     return `sed "$sc" ldscripts/${EMULATION_NAME}.xbn`;
 414   else if (!config.magic_demand_paged)
 415     return `sed "$sc" ldscripts/${EMULATION_NAME}.xn`;
 416   else if (link_info.shared)
 417     return `sed "$sc" ldscripts/${EMULATION_NAME}.xs`;
 418   else
 419     return `sed "$sc" ldscripts/${EMULATION_NAME}.x`;
 420 }
 421 EOF
 422
 423 else
 424 # Scripts read from the filesystem.
 425
 426 cat >>e${EMULATION_NAME}.c <<EOF
 427 {
 428   *isfile = 1;
 429
 430   if (link_info.relocateable == true && config.build_constructors == true)
 431     return "ldscripts/${EMULATION_NAME}.xu";
 432   else if (link_info.relocateable == true)
 433     return "ldscripts/${EMULATION_NAME}.xr";
 434   else if (!config.text_read_only)
 435     return "ldscripts/${EMULATION_NAME}.xbn";
 436   else if (!config.magic_demand_paged)
 437     return "ldscripts/${EMULATION_NAME}.xn";
 438   else if (link_info.shared)
 439     return "ldscripts/${EMULATION_NAME}.xs";
 440   else
 441     return "ldscripts/${EMULATION_NAME}.x";
 442 }
 443 EOF
 444
 445 fi
 446
 447 cat >>e${EMULATION_NAME}.c <<EOF
 448
 449 struct ld_emulation_xfer_struct ld_${EMULATION_NAME}_emulation =
 450 {
 451   gld${EMULATION_NAME}_before_parse,
 452   syslib_default,
 453   hll_default,
 454   after_parse_default,
 455   after_open_default,
 456   after_allocation_default,
 457   set_output_arch_default,
 458   ldemul_default_target,
 459   gld${EMULATION_NAME}_before_allocation,
 460   gld${EMULATION_NAME}_get_script,
 461   "${EMULATION_NAME}",
 462   "${OUTPUT_FORMAT}",
 463   NULL,
 464   NULL,
 465   gld${EMULATION_NAME}_open_dynamic_archive,
 466   gld${EMULATION_NAME}_place_orphan
 467 };
 468 EOF