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   snew = os->bfd_section;
 156   bfd_section = place->os->bfd_section;
 157   if (place->section == NULL && bfd_section == NULL)
 158     bfd_section = output_prev_sec_find (place->os);
 159
 160   if (place->section != NULL
 161       || (bfd_section != NULL
 162           && bfd_section != snew))
 163     {
 164       /* Shuffle the section to make the output file look neater.  This is
 165          really only cosmetic.  */
 166       if (place->section == NULL)
 167         /* Put orphans after the first section on the list.  */
 168         place->section = &bfd_section->next;
 169
 170       /* Unlink the section.  */
 171       for (pps = &output_bfd->sections; *pps != snew; pps = &(*pps)->next)
 172         ;
 173       bfd_section_list_remove (output_bfd, pps);
 174
 175       /* Now tack it on to the "place->os" section list.  */
 176       bfd_section_list_insert (output_bfd, place->section, snew);
 177     }
 178   place->section = &snew->next; /* Save the end of this list.  */
 179
 180   if (add.head != NULL)
 181     {
 182       /* We try to put the output statements in some sort of reasonable
 183          order here, because they determine the final load addresses of
 184          the orphan sections.  */
 185       if (place->stmt == NULL)
 186         {
 187           /* Put the new statement list right at the head.  */
 188           *add.tail = place->os->header.next;
 189           place->os->header.next = add.head;
 190         }
 191       else
 192         {
 193           /* Put it after the last orphan statement we added.  */
 194           *add.tail = *place->stmt;
 195           *place->stmt = add.head;
 196         }
 197
 198       /* Fix the global list pointer if we happened to tack our new list
 199          at the tail.  */
 200       if (*old->tail == add.head)
 201         old->tail = add.tail;
 202
 203       /* Save the end of this list.  */
 204       place->stmt = add.tail;
 205     }
 206
 207   return true;
 208 }
 209
 210 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 211    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 212    paper over the bug similarly.  */
 213
 214 static void
 215 mmo_wipe_sec_reloc_flag (abfd, sec, ptr)
 216      bfd *abfd;
 217      asection *sec;
 218      PTR ptr ATTRIBUTE_UNUSED;
 219 {
 220   bfd_set_section_flags (abfd, sec,
 221                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 222 }
 223
 224 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 225
 226 static void
 227 mmo_finish ()
 228 {
 229   bfd_map_over_sections (output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 230 }
 231 \f
 232 /* To get on-demand global register allocation right, we need to parse the
 233    relocs, like what happens when linking to ELF.  It needs to be done
 234    before all input sections are supposed to be present.  When linking to
 235    ELF, it's done when reading symbols.  When linking to mmo, we do it
 236    when all input files are seen, which is equivalent.  */
 237
 238 static void
 239 mmo_after_open ()
 240 {
 241   /* When there's a mismatch between the output format and the emulation
 242      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 243      example), we'd count relocs twice because they'd also be counted
 244      along the usual route for ELF-only linking, which would lead to an
 245      internal accounting error.  */
 246   if (bfd_get_flavour (output_bfd) != bfd_target_elf_flavour)
 247     {
 248       LANG_FOR_EACH_INPUT_STATEMENT (is)
 249         {
 250           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 251               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 252             einfo ("%X%P: Internal problems scanning %B after opening it",
 253                    is->the_bfd);
 254         }
 255     }
 256 }
 257 EOF
 258
 259 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 260 LDEMUL_FINISH=mmo_finish
 261 LDEMUL_AFTER_OPEN=mmo_after_open