ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
   3 #
   4 # This file is part of GLD, the Gnu Linker.
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19 #
  20
  21 # This file is sourced from elf32.em and mmo.em, used to define
  22 # linker MMIX-specifics common to ELF and MMO.
  23
  24 cat >>e${EMULATION_NAME}.c <<EOF
  25 /* Need to have this define before mmix-elfnmmo, which includes
  26    needrelax.em which uses this name for the before_allocation function,
  27    normally defined in elf32.em.  */
  28 #define gldmmo_before_allocation before_allocation_default
  29 EOF
  30
  31 . ${srcdir}/emultempl/mmix-elfnmmo.em
  32
  33 cat >>e${EMULATION_NAME}.c <<EOF
  34
  35 static bfd_boolean mmo_place_orphan
  36   PARAMS ((lang_input_statement_type *, asection *));
  37 static asection *output_prev_sec_find
  38   PARAMS ((lang_output_section_statement_type *));
  39 static void mmo_finish PARAMS ((void));
  40 static void mmo_wipe_sec_reloc_flag PARAMS ((bfd *, asection *, PTR));
  41 static void mmo_after_open PARAMS ((void));
  42
  43 /* Find the last output section before given output statement.
  44    Used by place_orphan.  */
  45
  46 static asection *
  47 output_prev_sec_find (os)
  48      lang_output_section_statement_type *os;
  49 {
  50   asection *s = (asection *) NULL;
  51   lang_statement_union_type *u;
  52   lang_output_section_statement_type *lookup;
  53
  54   for (u = lang_output_section_statement.head;
  55        u != (lang_statement_union_type *) NULL;
  56        u = lookup->next)
  57     {
  58       lookup = &u->output_section_statement;
  59       if (lookup == os)
  60         break;
  61       if (lookup->bfd_section != NULL
  62           && lookup->bfd_section != bfd_abs_section_ptr
  63           && lookup->bfd_section != bfd_com_section_ptr
  64           && lookup->bfd_section != bfd_und_section_ptr)
  65         s = lookup->bfd_section;
  66     }
  67
  68   if (u == NULL)
  69     return NULL;
  70
  71   return s;
  72 }
  73
  74 struct orphan_save {
  75   lang_output_section_statement_type *os;
  76   asection **section;
  77   lang_statement_union_type **stmt;
  78 };
  79
  80 #define HAVE_SECTION(hold, name) \
  81 (hold.os != NULL || (hold.os = lang_output_section_find (name)) != NULL)
  82
  83 /* Place an orphan section.  We use this to put random SEC_CODE or
  84    SEC_READONLY sections right after MMO_TEXT_SECTION_NAME.  Much borrowed
  85    from elf32.em.  */
  86
  87 static bfd_boolean
  88 mmo_place_orphan (file, s)
  89         lang_input_statement_type *file;
  90         asection *s;
  91 {
  92   static struct orphan_save hold_text;
  93   struct orphan_save *place;
  94   lang_output_section_statement_type *os;
  95   lang_statement_list_type *old;
  96   lang_statement_list_type add;
  97   asection *snew, **pps, *bfd_section;
  98
  99   /* We have nothing to say for anything other than a final link.  */
 100   if (link_info.relocatable
 101       || (bfd_get_section_flags (s->owner, s)
 102           & (SEC_EXCLUDE | SEC_LOAD)) != SEC_LOAD)
 103     return FALSE;
 104
 105   /* Only care for sections we're going to load.  */
 106   os = lang_output_section_find (bfd_get_section_name (s->owner, s));
 107
 108   /* We have an output section by this name.  Place the section inside it
 109      (regardless of whether the linker script lists it as input).  */
 110   if (os != NULL)
 111     {
 112       lang_add_section (&os->children, s, os, file);
 113       return TRUE;
 114     }
 115
 116   /* If this section does not have .text-type section flags or there's no
 117      MMO_TEXT_SECTION_NAME, we don't have anything to say.  */
 118   if ((bfd_get_section_flags (s->owner, s) & (SEC_CODE | SEC_READONLY)) == 0)
 119     return FALSE;
 120
 121   if (hold_text.os == NULL)
 122     hold_text.os = lang_output_section_find (MMO_TEXT_SECTION_NAME);
 123
 124   place = &hold_text;
 125
 126   /* If there's an output section by this name, we'll use it, regardless
 127      of section flags, in contrast to what's done in elf32.em.  */
 128
 129   /* Start building a list of statements for this section.
 130      First save the current statement pointer.  */
 131   old = stat_ptr;
 132
 133   /* Add the output section statements for this orphan to our own private
 134      list, inserting them later into the global statement list.  */
 135   stat_ptr = &add;
 136   lang_list_init (stat_ptr);
 137
 138   os = lang_enter_output_section_statement (bfd_get_section_name (s->owner,
 139                                                                   s),
 140                                             NULL, 0,
 141                                             (bfd_vma) 0,
 142                                             (etree_type *) NULL,
 143                                             (etree_type *) NULL,
 144                                             (etree_type *) NULL);
 145
 146   lang_add_section (&os->children, s, os, file);
 147
 148   lang_leave_output_section_statement
 149     ((bfd_vma) 0, "*default*",
 150      (struct lang_output_section_phdr_list *) NULL, NULL);
 151
 152   /* Restore the global list pointer.  */
 153   stat_ptr = old;
 154
 155   snew = os->bfd_section;
 156   if (snew == NULL)
 157     /* /DISCARD/ section.  */
 158     return TRUE;
 159
 160   /* We need an output section for .text as a root, so if there was none
 161      (might happen with a peculiar linker script such as in "map
 162      addresses", map-address.exp), we grab the output section created
 163      above.  */
 164   if (hold_text.os == NULL)
 165     {
 166       if (os == NULL)
 167         return FALSE;
 168       hold_text.os = os;
 169     }
 170
 171   bfd_section = place->os->bfd_section;
 172   if (place->section == NULL && bfd_section == NULL)
 173     bfd_section = output_prev_sec_find (place->os);
 174
 175   if (place->section != NULL
 176       || (bfd_section != NULL
 177           && bfd_section != snew))
 178     {
 179       /* Shuffle the section to make the output file look neater.  This is
 180          really only cosmetic.  */
 181       if (place->section == NULL)
 182         /* Put orphans after the first section on the list.  */
 183         place->section = &bfd_section->next;
 184
 185       /* Unlink the section.  */
 186       for (pps = &output_bfd->sections; *pps != snew; pps = &(*pps)->next)
 187         ;
 188       bfd_section_list_remove (output_bfd, pps);
 189
 190       /* Now tack it on to the "place->os" section list.  */
 191       bfd_section_list_insert (output_bfd, place->section, snew);
 192     }
 193   place->section = &snew->next; /* Save the end of this list.  */
 194
 195   if (add.head != NULL)
 196     {
 197       /* We try to put the output statements in some sort of reasonable
 198          order here, because they determine the final load addresses of
 199          the orphan sections.  */
 200       if (place->stmt == NULL)
 201         {
 202           /* Put the new statement list right at the head.  */
 203           *add.tail = place->os->header.next;
 204           place->os->header.next = add.head;
 205         }
 206       else
 207         {
 208           /* Put it after the last orphan statement we added.  */
 209           *add.tail = *place->stmt;
 210           *place->stmt = add.head;
 211         }
 212
 213       /* Fix the global list pointer if we happened to tack our new list
 214          at the tail.  */
 215       if (*old->tail == add.head)
 216         old->tail = add.tail;
 217
 218       /* Save the end of this list.  */
 219       place->stmt = add.tail;
 220     }
 221
 222   return TRUE;
 223 }
 224
 225 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 226    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 227    paper over the bug similarly.  */
 228
 229 static void
 230 mmo_wipe_sec_reloc_flag (abfd, sec, ptr)
 231      bfd *abfd;
 232      asection *sec;
 233      PTR ptr ATTRIBUTE_UNUSED;
 234 {
 235   bfd_set_section_flags (abfd, sec,
 236                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 237 }
 238
 239 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 240
 241 static void
 242 mmo_finish ()
 243 {
 244   bfd_map_over_sections (output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 245 }
 246 \f
 247 /* To get on-demand global register allocation right, we need to parse the
 248    relocs, like what happens when linking to ELF.  It needs to be done
 249    before all input sections are supposed to be present.  When linking to
 250    ELF, it's done when reading symbols.  When linking to mmo, we do it
 251    when all input files are seen, which is equivalent.  */
 252
 253 static void
 254 mmo_after_open ()
 255 {
 256   /* When there's a mismatch between the output format and the emulation
 257      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 258      example), we'd count relocs twice because they'd also be counted
 259      along the usual route for ELF-only linking, which would lead to an
 260      internal accounting error.  */
 261   if (bfd_get_flavour (output_bfd) != bfd_target_elf_flavour)
 262     {
 263       LANG_FOR_EACH_INPUT_STATEMENT (is)
 264         {
 265           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 266               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 267             einfo ("%X%P: Internal problems scanning %B after opening it",
 268                    is->the_bfd);
 269         }
 270     }
 271 }
 272 EOF
 273
 274 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 275 LDEMUL_FINISH=mmo_finish
 276 LDEMUL_AFTER_OPEN=mmo_after_open