xref: /netbsd-src/external/gpl3/binutils/dist/ld/emultempl/mmo.em (revision a24efa7dea9f1f56c3bdb15a927d3516792ace1c)
1# This shell script emits a C file. -*- C -*-
2#   Copyright (C) 2001-2015 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
24fragment <<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
38static void gld${EMULATION_NAME}_after_allocation (void);
39EOF
40
41source_em ${srcdir}/emultempl/elf-generic.em
42source_em ${srcdir}/emultempl/mmix-elfnmmo.em
43
44fragment <<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
50static lang_output_section_statement_type *
51mmo_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
189static void
190mmo_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
198static void
199gld${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
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
211static void
212mmo_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}
231EOF
232
233LDEMUL_PLACE_ORPHAN=mmo_place_orphan
234LDEMUL_AFTER_OPEN=mmo_after_open
235