ld/emultempl/mmo.em

   1 # This shell script emits a C file. -*- C -*-
   2 #   Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   3 #   Free Software Foundation, Inc.
   4 #
   5 # This file is part of the GNU Binutils.
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License as published by
   9 # the Free Software Foundation; either version 3 of the License, or
  10 # (at your option) any later version.
  11 #
  12 # This program is distributed in the hope that it will be useful,
  13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 # GNU General Public License for more details.
  16 #
  17 # You should have received a copy of the GNU General Public License
  18 # along with this program; if not, write to the Free Software
  19 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
  20 # MA 02110-1301, USA.
  21 #
  22
  23 # This file is sourced from generic.em.
  24
  25 fragment <<EOF
  26 /* Need to have this macro defined before mmix-elfnmmo, which uses the
  27    name for the before_allocation function, defined in ldemul.c (for
  28    the mmo "emulation") or in elf32.em (for the elf64mmix
  29    "emulation").  */
  30 #define gldmmo_before_allocation before_allocation_default
  31
  32 /* We include this header *not* because we expect to handle ELF here
  33    but because we re-use the map_segments function in elf-generic.em,
  34    a file which is rightly somewhat ELF-centric.  But this is only to
  35    get a weird testcase right; ld-mmix/bpo-22, forcing ELF to be
  36    output from the mmo emulation: -m mmo --oformat elf64-mmix!  */
  37 #include "elf-bfd.h"
  38
  39 static void gld${EMULATION_NAME}_after_allocation (void);
  40 EOF
  41
  42 source_em ${srcdir}/emultempl/elf-generic.em
  43 source_em ${srcdir}/emultempl/mmix-elfnmmo.em
  44
  45 fragment <<EOF
  46
  47 /* Place an orphan section.  We use this to put random SEC_CODE or
  48    SEC_READONLY sections right after MMO_TEXT_SECTION_NAME.  Much borrowed
  49    from elf32.em.  */
  50
  51 static lang_output_section_statement_type *
  52 mmo_place_orphan (asection *s,
  53                   const char *secname,
  54                   int constraint ATTRIBUTE_UNUSED)
  55 {
  56   static struct
  57   {
  58     flagword nonzero_flags;
  59     struct orphan_save orphansave;
  60   } holds[] =
  61       {
  62         {
  63           SEC_CODE | SEC_READONLY,
  64           {
  65             MMO_TEXT_SECTION_NAME,
  66             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE,
  67             0, 0, 0, 0
  68           }
  69         },
  70         {
  71           SEC_LOAD | SEC_DATA,
  72           {
  73             MMO_DATA_SECTION_NAME,
  74             SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_DATA,
  75             0, 0, 0, 0
  76           }
  77         },
  78         {
  79           SEC_ALLOC,
  80           {
  81             ".bss",
  82             SEC_ALLOC,
  83             0, 0, 0, 0
  84           }
  85         }
  86       };
  87
  88   struct orphan_save *place = NULL;
  89   lang_output_section_statement_type *after;
  90   lang_output_section_statement_type *os;
  91   size_t i;
  92
  93   /* We have nothing to say for anything other than a final link or
  94      for sections that are excluded.  */
  95   if (link_info.relocatable
  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, os);
 106       return os;
 107     }
 108
 109   /* Check for matching section type flags for sections we care about.
 110      A section without contents can have SEC_LOAD == 0, but we still
 111      want it attached to a sane section so the symbols appear as
 112      expected.  */
 113   if ((s->flags & (SEC_ALLOC | SEC_READONLY)) != SEC_READONLY)
 114     for (i = 0; i < sizeof (holds) / sizeof (holds[0]); i++)
 115       if ((s->flags & holds[i].nonzero_flags) != 0)
 116         {
 117           place = &holds[i].orphansave;
 118           if (place->os == NULL)
 119             place->os = lang_output_section_find (place->name);
 120           break;
 121         }
 122
 123   if (place == NULL)
 124     {
 125       /* For other combinations, we have to give up, except we make
 126          sure not to place the orphan section after the
 127          linker-generated register section; that'd make it continue
 128          the reg section and we never want that to happen for orphan
 129          sections.  */
 130       lang_output_section_statement_type *before;
 131       lang_output_section_statement_type *lookup;
 132       static struct orphan_save hold_nonreg =
 133         {
 134           NULL,
 135           SEC_READONLY,
 136           0, 0, 0, 0
 137         };
 138
 139       if (hold_nonreg.os == NULL)
 140         {
 141           before = lang_output_section_find (MMIX_REG_CONTENTS_SECTION_NAME);
 142
 143           /* If we have no such section, all fine; we don't care where
 144              it's placed.  */
 145           if (before == NULL)
 146             return NULL;
 147
 148           /* We have to find the oss before this one, so we can use that as
 149              "after".  */
 150           for (lookup = &lang_output_section_statement.head->output_section_statement;
 151                lookup != NULL && lookup->next != before;
 152                lookup = lookup->next)
 153             ;
 154
 155           hold_nonreg.os = lookup;
 156         }
 157
 158       place = &hold_nonreg;
 159     }
 160
 161   after = place->os;
 162   if (after == NULL)
 163     return NULL;
 164
 165   /* If there's an output section by *this* name, we'll use it, regardless
 166      of actual section flags, in contrast to what's done in elf32.em.  */
 167   os = lang_insert_orphan (s, secname, 0, after, place, NULL, NULL);
 168
 169   return os;
 170 }
 171
 172 /* Remove the spurious settings of SEC_RELOC that make it to the output at
 173    link time.  We are as confused as elflink.h:elf_bfd_final_link, and
 174    paper over the bug similarly.  */
 175
 176 static void
 177 mmo_wipe_sec_reloc_flag (bfd *abfd, asection *sec, void *ptr ATTRIBUTE_UNUSED)
 178 {
 179   bfd_set_section_flags (abfd, sec,
 180                          bfd_get_section_flags (abfd, sec) & ~SEC_RELOC);
 181 }
 182
 183 /* Iterate with bfd_map_over_sections over mmo_wipe_sec_reloc_flag... */
 184
 185 static void
 186 gld${EMULATION_NAME}_after_allocation (void)
 187 {
 188   bfd_map_over_sections (link_info.output_bfd, mmo_wipe_sec_reloc_flag, NULL);
 189   gld${EMULATION_NAME}_map_segments (FALSE);
 190 }
 191 \f
 192 /* To get on-demand global register allocation right, we need to parse the
 193    relocs, like what happens when linking to ELF.  It needs to be done
 194    before all input sections are supposed to be present.  When linking to
 195    ELF, it's done when reading symbols.  When linking to mmo, we do it
 196    when all input files are seen, which is equivalent.  */
 197
 198 static void
 199 mmo_after_open (void)
 200 {
 201   /* When there's a mismatch between the output format and the emulation
 202      (using weird combinations like "-m mmo --oformat elf64-mmix" for
 203      example), we'd count relocs twice because they'd also be counted
 204      along the usual route for ELF-only linking, which would lead to an
 205      internal accounting error.  */
 206   if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
 207     {
 208       LANG_FOR_EACH_INPUT_STATEMENT (is)
 209         {
 210           if (bfd_get_flavour (is->the_bfd) == bfd_target_elf_flavour
 211               && !_bfd_mmix_check_all_relocs (is->the_bfd, &link_info))
 212             einfo ("%X%P: Internal problems scanning %B after opening it",
 213                    is->the_bfd);
 214         }
 215     }
 216   after_open_default ();
 217 }
 218 EOF
 219
 220 LDEMUL_PLACE_ORPHAN=mmo_place_orphan
 221 LDEMUL_AFTER_OPEN=mmo_after_open