ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2001, 2002 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 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 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.relocateable
 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   /* We need an output section for .text as a root, so if there was none
 156      (might happen with a peculiar linker script such as in "map
 157      addresses", map-address.exp), we grab the output section created
 158      above.  */
 159   if (hold_text.os == NULL)
 160     {
 161       if (os == NULL)
 162         return false;
 163       hold_text.os = os;
 164     }
 165
 166   snew = os->bfd_section;
 167   bfd_section = place->os->bfd_section;
 168   if (place->section == NULL && bfd_section == NULL)
 169     bfd_section = output_prev_sec_find (place->os);
 170
 171   if (place->section != NULL
 172       || (bfd_section != NULL
 173           && bfd_section != snew))
 174     {
 175       /* Shuffle the section to make the output file look neater.  This is
 176          really only cosmetic.  */
 177       if (place->section == NULL)
 178         /* Put orphans after the first section on the list.  */
 179         place->section = &bfd_section->next;
 180
 181       /* Unlink the section.  */
 182       for (pps = &output_bfd->sections; *pps != snew; pps = &(*pps)->next)
 183         ;
 184       bfd_section_list_remove (output_bfd, pps);
 185
 186       /* Now tack it on to the "place->os" section list.  */
 187       bfd_section_list_insert (output_bfd, place->section, snew);
 188     }
 189   place->section = &snew->next; /* Save the end of this list.  */
 190
 191   if (add.head != NULL)
 192     {
 193       /* We try to put the output statements in some sort of reasonable
 194          order here, because they determine the final load addresses of
 195          the orphan sections.  */
 196       if (place->stmt == NULL)
 197         {
 198           /* Put the new statement list right at the head.  */
 199           *add.tail = place->os->header.next;
 200           place->os->header.next = add.head;
 201         }
 202       else
 203         {
 204           /* Put it after the last orphan statement we added.  */
 205           *add.tail = *place->stmt;
 206           *place->stmt = add.head;
 207         }
 208
 209       /* Fix the global list pointer if we happened to tack our new list
 210          at the tail.  */
 211       if (*old->tail == add.head)
 212         old->tail = add.tail;
 213
 214       /* Save the end of this list.  */
 215       place->stmt = add.tail;
 216     }
 217
 218   return true;
 219 }
 220
 221 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 222    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 223    paper over the bug similarly.  */
 224
 225 static void
 226 mmo_wipe_sec_reloc_flag (abfd, sec, ptr)
 227      bfd *abfd;
 228      asection *sec;
 229      PTR ptr ATTRIBUTE_UNUSED;
 230 {
 231   bfd_set_section_flags (abfd, sec,
 232                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 233 }
 234
 235 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 236
 237 static void
 238 mmo_finish ()
 239 {
 240   bfd_map_over_sections (output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 241 }
 242 \f
 243 /* To get on-demand global register allocation right, we need to parse the
 244    relocs, like what happens when linking to ELF.  It needs to be done
 245    before all input sections are supposed to be present.  When linking to
 246    ELF, it's done when reading symbols.  When linking to mmo, we do it
 247    when all input files are seen, which is equivalent.  */
 248
 249 static void
 250 mmo_after_open ()
 251 {
 252   /* When there's a mismatch between the output format and the emulation
 253      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 254      example), we'd count relocs twice because they'd also be counted
 255      along the usual route for ELF-only linking, which would lead to an
 256      internal accounting error.  */
 257   if (bfd_get_flavour (output_bfd) != bfd_target_elf_flavour)
 258     {
 259       LANG_FOR_EACH_INPUT_STATEMENT (is)
 260         {
 261           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 262               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 263             einfo ("%X%P: Internal problems scanning %B after opening it",
 264                    is->the_bfd);
 265         }
 266     }
 267 }
 268 EOF
 269
 270 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 271 LDEMUL_FINISH=mmo_finish
 272 LDEMUL_AFTER_OPEN=mmo_after_open