ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright (C) 2001-2022 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 elf.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 use the map_segments function.  But this is only to
  33    get a weird testcase right; ld-mmix/bpo-22, forcing ELF to be
  34    output from the mmo emulation: -m mmo --oformat elf64-mmix!  */
  35 #include "ldelfgen.h"
  36
  37 static void gld${EMULATION_NAME}_after_allocation (void);
  38 EOF
  39
  40 source_em ${srcdir}/emultempl/elf-generic.em
  41 source_em ${srcdir}/emultempl/mmix-elfnmmo.em
  42
  43 fragment <<EOF
  44
  45 /* Place an orphan section.  We use this to put random SEC_CODE or
  46    SEC_READONLY sections right after MMO_TEXT_SECTION_NAME.  Much borrowed
  47    from elf.em.  */
  48
  49 static lang_output_section_statement_type *
  50 mmo_place_orphan (asection *s,
  51                   const char *secname,
  52                   int constraint ATTRIBUTE_UNUSED)
  53 {
  54   static struct
  55   {
  56     flagword nonzero_flags;
  57     struct orphan_save orphansave;
  58   } holds[] =
  59       {
  60         {
  61           SEC_CODE | SEC_READONLY,
  62           {
  63             MMO_TEXT_SECTION_NAME,
  64             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE,
  65             0, 0, 0, 0
  66           }
  67         },
  68         {
  69           SEC_LOAD | SEC_DATA,
  70           {
  71             MMO_DATA_SECTION_NAME,
  72             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_DATA,
  73             0, 0, 0, 0
  74           }
  75         },
  76         {
  77           SEC_ALLOC,
  78           {
  79             ".bss",
  80             SEC_ALLOC,
  81             0, 0, 0, 0
  82           }
  83         }
  84       };
  85
  86   struct orphan_save *place = NULL;
  87   lang_output_section_statement_type *after;
  88   lang_output_section_statement_type *os;
  89   size_t i;
  90   flagword flags;
  91   asection *nexts;
  92
  93   /* We have nothing to say for anything other than a final link or
  94      for sections that are excluded.  */
  95   if (bfd_link_relocatable (&link_info)
  96       || (s->flags & SEC_EXCLUDE) != 0)
  97     return NULL;
  98
  99   os = lang_output_section_find (secname);
 100
 101   /* We have an output section by this name.  Place the section inside it
 102      (regardless of whether the linker script lists it as input).  */
 103   if (os != NULL)
 104     {
 105       lang_add_section (&os->children, s, NULL, NULL, os);
 106       return os;
 107     }
 108
 109   flags = s->flags;
 110   if (!bfd_link_relocatable (&link_info))
 111     {
 112       nexts = s;
 113       while ((nexts = bfd_get_next_section_by_name (nexts->owner, nexts))
 114              != NULL)
 115         if (nexts->output_section == NULL
 116             && (nexts->flags & SEC_EXCLUDE) == 0
 117             && ((nexts->flags ^ flags) & (SEC_LOAD | SEC_ALLOC)) == 0
 118             && (nexts->owner->flags & DYNAMIC) == 0
 119             && !bfd_input_just_syms (nexts->owner))
 120           flags = (((flags ^ SEC_READONLY) | (nexts->flags ^ SEC_READONLY))
 121                    ^ SEC_READONLY);
 122     }
 123
 124   /* Check for matching section type flags for sections we care about.
 125      A section without contents can have SEC_LOAD == 0, but we still
 126      want it attached to a sane section so the symbols appear as
 127      expected.  */
 128
 129   if ((flags & (SEC_ALLOC | SEC_READONLY)) != SEC_READONLY)
 130     for (i = 0; i < sizeof (holds) / sizeof (holds[0]); i++)
 131       if ((flags & holds[i].nonzero_flags) != 0)
 132         {
 133           place = &holds[i].orphansave;
 134           if (place->os == NULL)
 135             place->os = lang_output_section_find (place->name);
 136           break;
 137         }
 138
 139   if (place == NULL)
 140     {
 141       /* For other combinations, we have to give up, except we make
 142          sure not to place the orphan section after the
 143          linker-generated register section; that'd make it continue
 144          the reg section and we never want that to happen for orphan
 145          sections.  */
 146       lang_output_section_statement_type *before;
 147       lang_output_section_statement_type *lookup;
 148       static struct orphan_save hold_nonreg =
 149         {
 150           NULL,
 151           SEC_READONLY,
 152           0, 0, 0, 0
 153         };
 154
 155       if (hold_nonreg.os == NULL)
 156         {
 157           before = lang_output_section_find (MMIX_REG_CONTENTS_SECTION_NAME);
 158
 159           /* If we have no such section, all fine; we don't care where
 160              it's placed.  */
 161           if (before == NULL)
 162             return NULL;
 163
 164           /* We have to find the oss before this one, so we can use that as
 165              "after".  */
 166           for (lookup = (void *) lang_os_list.head;
 167                lookup != NULL && lookup->next != before;
 168                lookup = lookup->next)
 169             ;
 170
 171           hold_nonreg.os = lookup;
 172         }
 173
 174       place = &hold_nonreg;
 175     }
 176
 177   after = place->os;
 178   if (after == NULL)
 179     return NULL;
 180
 181   /* If there's an output section by *this* name, we'll use it, regardless
 182      of actual section flags, in contrast to what's done in elf.em.  */
 183   os = lang_insert_orphan (s, secname, 0, after, place, NULL, NULL);
 184
 185   return os;
 186 }
 187
 188 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 189    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 190    paper over the bug similarly.  */
 191
 192 static void
 193 mmo_wipe_sec_reloc_flag (bfd *abfd ATTRIBUTE_UNUSED, asection *sec,
 194                          void *ptr ATTRIBUTE_UNUSED)
 195 {
 196   bfd_set_section_flags (sec, bfd_section_flags (sec) & ~SEC_RELOC);
 197 }
 198
 199 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 200
 201 static void
 202 gld${EMULATION_NAME}_after_allocation (void)
 203 {
 204   bfd_map_over_sections (link_info.output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 205   ldelf_map_segments (false);
 206 }
 207 \f
 208 /* To get on-demand global register allocation right, we need to parse the
 209    relocs, like what happens when linking to ELF.  It needs to be done
 210    before all input sections are supposed to be present.  When linking to
 211    ELF, it's done when reading symbols.  When linking to mmo, we do it
 212    when all input files are seen, which is equivalent.  */
 213
 214 static void
 215 mmo_after_open (void)
 216 {
 217   /* When there's a mismatch between the output format and the emulation
 218      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 219      example), we'd count relocs twice because they'd also be counted
 220      along the usual route for ELF-only linking, which would lead to an
 221      internal accounting error.  */
 222   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 223     {
 224       LANG_FOR_EACH_INPUT_STATEMENT (is)
 225         {
 226           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 227               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 228             einfo (_("%X%P: internal problems scanning %pB after opening it"),
 229                    is->the_bfd);
 230         }
 231     }
 232   after_open_default ();
 233 }
 234 EOF
 235
 236 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 237 LDEMUL_AFTER_OPEN=mmo_after_open