ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2001-2018 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   flags = s->flags;
 111   if (!bfd_link_relocatable (&link_info))
 112     {
 113       nexts = s;
 114       while ((nexts = bfd_get_next_section_by_name (nexts->owner, nexts))
 115              != NULL)
 116         if (nexts->output_section == NULL
 117             && (nexts->flags & SEC_EXCLUDE) == 0
 118             && ((nexts->flags ^ flags) & (SEC_LOAD | SEC_ALLOC)) == 0
 119             && (nexts->owner->flags & DYNAMIC) == 0
 120             && nexts->owner->usrdata != NULL
 121             && !(((lang_input_statement_type *) nexts->owner->usrdata)
 122                  ->flags.just_syms))
 123           flags = (((flags ^ SEC_READONLY) | (nexts->flags ^ SEC_READONLY))
 124                    ^ SEC_READONLY);
 125     }
 126
 127   /* Check for matching section type flags for sections we care about.
 128      A section without contents can have SEC_LOAD == 0, but we still
 129      want it attached to a sane section so the symbols appear as
 130      expected.  */
 131
 132   if ((flags & (SEC_ALLOC | SEC_READONLY)) != SEC_READONLY)
 133     for (i = 0; i < sizeof (holds) / sizeof (holds[0]); i++)
 134       if ((flags & holds[i].nonzero_flags) != 0)
 135         {
 136           place = &holds[i].orphansave;
 137           if (place->os == NULL)
 138             place->os = lang_output_section_find (place->name);
 139           break;
 140         }
 141
 142   if (place == NULL)
 143     {
 144       /* For other combinations, we have to give up, except we make
 145          sure not to place the orphan section after the
 146          linker-generated register section; that'd make it continue
 147          the reg section and we never want that to happen for orphan
 148          sections.  */
 149       lang_output_section_statement_type *before;
 150       lang_output_section_statement_type *lookup;
 151       static struct orphan_save hold_nonreg =
 152         {
 153           NULL,
 154           SEC_READONLY,
 155           0, 0, 0, 0
 156         };
 157
 158       if (hold_nonreg.os == NULL)
 159         {
 160           before = lang_output_section_find (MMIX_REG_CONTENTS_SECTION_NAME);
 161
 162           /* If we have no such section, all fine; we don't care where
 163              it's placed.  */
 164           if (before == NULL)
 165             return NULL;
 166
 167           /* We have to find the oss before this one, so we can use that as
 168              "after".  */
 169           for (lookup = &lang_output_section_statement.head->output_section_statement;
 170                lookup != NULL && lookup->next != before;
 171                lookup = lookup->next)
 172             ;
 173
 174           hold_nonreg.os = lookup;
 175         }
 176
 177       place = &hold_nonreg;
 178     }
 179
 180   after = place->os;
 181   if (after == NULL)
 182     return NULL;
 183
 184   /* If there's an output section by *this* name, we'll use it, regardless
 185      of actual section flags, in contrast to what's done in elf32.em.  */
 186   os = lang_insert_orphan (s, secname, 0, after, place, NULL, NULL);
 187
 188   return os;
 189 }
 190
 191 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 192    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 193    paper over the bug similarly.  */
 194
 195 static void
 196 mmo_wipe_sec_reloc_flag (bfd *abfd, asection *sec, void *ptr ATTRIBUTE_UNUSED)
 197 {
 198   bfd_set_section_flags (abfd, sec,
 199                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 200 }
 201
 202 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 203
 204 static void
 205 gld${EMULATION_NAME}_after_allocation (void)
 206 {
 207   bfd_map_over_sections (link_info.output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 208   gld${EMULATION_NAME}_map_segments (FALSE);
 209 }
 210 \f
 211 /* To get on-demand global register allocation right, we need to parse the
 212    relocs, like what happens when linking to ELF.  It needs to be done
 213    before all input sections are supposed to be present.  When linking to
 214    ELF, it's done when reading symbols.  When linking to mmo, we do it
 215    when all input files are seen, which is equivalent.  */
 216
 217 static void
 218 mmo_after_open (void)
 219 {
 220   /* When there's a mismatch between the output format and the emulation
 221      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 222      example), we'd count relocs twice because they'd also be counted
 223      along the usual route for ELF-only linking, which would lead to an
 224      internal accounting error.  */
 225   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 226     {
 227       LANG_FOR_EACH_INPUT_STATEMENT (is)
 228         {
 229           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 230               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 231             einfo (_("%X%P: Internal problems scanning %B after opening it"),
 232                    is->the_bfd);
 233         }
 234     }
 235   after_open_default ();
 236 }
 237 EOF
 238
 239 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 240 LDEMUL_AFTER_OPEN=mmo_after_open