ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2001-2016 Free Software Foundation, Inc.
   3 #
   4 # This file is part of the GNU Binutils.
   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 3 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., 51 Franklin Street - Fifth Floor, Boston,
  19 # MA 02110-1301, USA.
  20 #
  21
  22 # This file is sourced from generic.em.
  23
  24 fragment <<EOF
  25 /* Need to have this macro defined before mmix-elfnmmo, which uses the
  26    name for the before_allocation function, defined in ldemul.c (for
  27    the mmo "emulation") or in elf32.em (for the elf64mmix
  28    "emulation").  */
  29 #define gldmmo_before_allocation before_allocation_default
  30
  31 /* We include this header *not* because we expect to handle ELF here
  32    but because we re-use the map_segments function in elf-generic.em,
  33    a file which is rightly somewhat ELF-centric.  But this is only to
  34    get a weird testcase right; ld-mmix/bpo-22, forcing ELF to be
  35    output from the mmo emulation: -m mmo --oformat elf64-mmix!  */
  36 #include "elf-bfd.h"
  37
  38 static void gld${EMULATION_NAME}_after_allocation (void);
  39 EOF
  40
  41 source_em ${srcdir}/emultempl/elf-generic.em
  42 source_em ${srcdir}/emultempl/mmix-elfnmmo.em
  43
  44 fragment <<EOF
  45
  46 /* Place an orphan section.  We use this to put random SEC_CODE or
  47    SEC_READONLY sections right after MMO_TEXT_SECTION_NAME.  Much borrowed
  48    from elf32.em.  */
  49
  50 static lang_output_section_statement_type *
  51 mmo_place_orphan (asection *s,
  52                   const char *secname,
  53                   int constraint ATTRIBUTE_UNUSED)
  54 {
  55   static struct
  56   {
  57     flagword nonzero_flags;
  58     struct orphan_save orphansave;
  59   } holds[] =
  60       {
  61         {
  62           SEC_CODE | SEC_READONLY,
  63           {
  64             MMO_TEXT_SECTION_NAME,
  65             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE,
  66             0, 0, 0, 0
  67           }
  68         },
  69         {
  70           SEC_LOAD | SEC_DATA,
  71           {
  72             MMO_DATA_SECTION_NAME,
  73             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_DATA,
  74             0, 0, 0, 0
  75           }
  76         },
  77         {
  78           SEC_ALLOC,
  79           {
  80             ".bss",
  81             SEC_ALLOC,
  82             0, 0, 0, 0
  83           }
  84         }
  85       };
  86
  87   struct orphan_save *place = NULL;
  88   lang_output_section_statement_type *after;
  89   lang_output_section_statement_type *os;
  90   size_t i;
  91   flagword flags;
  92   asection *nexts;
  93
  94   /* We have nothing to say for anything other than a final link or
  95      for sections that are excluded.  */
  96   if (bfd_link_relocatable (&link_info)
  97       || (s->flags & SEC_EXCLUDE) != 0)
  98     return NULL;
  99
 100   os = lang_output_section_find (secname);
 101
 102   /* We have an output section by this name.  Place the section inside it
 103      (regardless of whether the linker script lists it as input).  */
 104   if (os != NULL)
 105     {
 106       lang_add_section (&os->children, s, NULL, os);
 107       return os;
 108     }
 109
 110   /* Check for matching section type flags for sections we care about.
 111      A section without contents can have SEC_LOAD == 0, but we still
 112      want it attached to a sane section so the symbols appear as
 113      expected.  */
 114   flags = s->flags;
 115   nexts = s;
 116   while ((nexts = bfd_get_next_section_by_name (nexts->owner, nexts)) != NULL)
 117     if (nexts->output_section == NULL
 118         && (nexts->flags & SEC_EXCLUDE) == 0
 119         && ((nexts->flags ^ flags) & (SEC_LOAD | SEC_ALLOC)) == 0
 120         && (nexts->owner->flags & DYNAMIC) == 0
 121         && nexts->owner->usrdata != NULL
 122         && !(((lang_input_statement_type *) nexts->owner->usrdata)
 123              ->flags.just_syms))
 124       flags = (((flags ^ SEC_READONLY) | (nexts->flags ^ SEC_READONLY))
 125                ^ SEC_READONLY);
 126   if ((flags & (SEC_ALLOC | SEC_READONLY)) != SEC_READONLY)
 127     for (i = 0; i < sizeof (holds) / sizeof (holds[0]); i++)
 128       if ((flags & holds[i].nonzero_flags) != 0)
 129         {
 130           place = &holds[i].orphansave;
 131           if (place->os == NULL)
 132             place->os = lang_output_section_find (place->name);
 133           break;
 134         }
 135
 136   if (place == NULL)
 137     {
 138       /* For other combinations, we have to give up, except we make
 139          sure not to place the orphan section after the
 140          linker-generated register section; that'd make it continue
 141          the reg section and we never want that to happen for orphan
 142          sections.  */
 143       lang_output_section_statement_type *before;
 144       lang_output_section_statement_type *lookup;
 145       static struct orphan_save hold_nonreg =
 146         {
 147           NULL,
 148           SEC_READONLY,
 149           0, 0, 0, 0
 150         };
 151
 152       if (hold_nonreg.os == NULL)
 153         {
 154           before = lang_output_section_find (MMIX_REG_CONTENTS_SECTION_NAME);
 155
 156           /* If we have no such section, all fine; we don't care where
 157              it's placed.  */
 158           if (before == NULL)
 159             return NULL;
 160
 161           /* We have to find the oss before this one, so we can use that as
 162              "after".  */
 163           for (lookup = &lang_output_section_statement.head->output_section_statement;
 164                lookup != NULL && lookup->next != before;
 165                lookup = lookup->next)
 166             ;
 167
 168           hold_nonreg.os = lookup;
 169         }
 170
 171       place = &hold_nonreg;
 172     }
 173
 174   after = place->os;
 175   if (after == NULL)
 176     return NULL;
 177
 178   /* If there's an output section by *this* name, we'll use it, regardless
 179      of actual section flags, in contrast to what's done in elf32.em.  */
 180   os = lang_insert_orphan (s, secname, 0, after, place, NULL, NULL);
 181
 182   return os;
 183 }
 184
 185 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 186    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 187    paper over the bug similarly.  */
 188
 189 static void
 190 mmo_wipe_sec_reloc_flag (bfd *abfd, asection *sec, void *ptr ATTRIBUTE_UNUSED)
 191 {
 192   bfd_set_section_flags (abfd, sec,
 193                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 194 }
 195
 196 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 197
 198 static void
 199 gld${EMULATION_NAME}_after_allocation (void)
 200 {
 201   bfd_map_over_sections (link_info.output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 202   gld${EMULATION_NAME}_map_segments (FALSE);
 203 }
 204 \f
 205 /* To get on-demand global register allocation right, we need to parse the
 206    relocs, like what happens when linking to ELF.  It needs to be done
 207    before all input sections are supposed to be present.  When linking to
 208    ELF, it's done when reading symbols.  When linking to mmo, we do it
 209    when all input files are seen, which is equivalent.  */
 210
 211 static void
 212 mmo_after_open (void)
 213 {
 214   /* When there's a mismatch between the output format and the emulation
 215      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 216      example), we'd count relocs twice because they'd also be counted
 217      along the usual route for ELF-only linking, which would lead to an
 218      internal accounting error.  */
 219   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 220     {
 221       LANG_FOR_EACH_INPUT_STATEMENT (is)
 222         {
 223           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 224               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 225             einfo ("%X%P: Internal problems scanning %B after opening it",
 226                    is->the_bfd);
 227         }
 228     }
 229   after_open_default ();
 230 }
 231 EOF
 232
 233 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 234 LDEMUL_AFTER_OPEN=mmo_after_open