1# This shell script emits a C file. -*- C -*-
2#   Copyright (C) 2013-2024 Free Software Foundation, Inc.
3#
4# This file is part of 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 elf.em, and defines extra Nios II ELF
23# specific routines. Taken from metagelf.em.
24#
25fragment <<EOF
26
27#include "ldctor.h"
28#include "elf32-nios2.h"
29
30
31/* Fake input file for stubs.  */
32static lang_input_statement_type *stub_file;
33
34/* Whether we need to call nios2_layout_sections_again.  */
35static int need_laying_out = 0;
36
37
38/* This is called before the input files are opened.  We create a new
39   fake input file to hold the stub sections.  */
40
41static void
42nios2elf_create_output_section_statements (void)
43{
44  extern const bfd_target nios2_elf32_le_vec, nios2_elf32_be_vec;
45
46  if (link_info.output_bfd->xvec != &nios2_elf32_le_vec
47      && link_info.output_bfd->xvec != &nios2_elf32_be_vec)
48    return;
49
50  /* If --no-relax was not explicitly specified by the user, enable
51     relaxation.  If it's not enabled (either explicitly or by default),
52     we're done, as we won't need to create any stubs.  */
53  if (!bfd_link_relocatable (&link_info) && RELAXATION_DISABLED_BY_DEFAULT)
54    ENABLE_RELAXATION;
55  if (!RELAXATION_ENABLED)
56    return;
57
58  stub_file = lang_add_input_file ("linker stubs",
59                                           lang_input_file_is_fake_enum,
60                                           NULL);
61  stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
62  if (stub_file->the_bfd == NULL
63      || ! bfd_set_arch_mach (stub_file->the_bfd,
64                                    bfd_get_arch (link_info.output_bfd),
65                                    bfd_get_mach (link_info.output_bfd)))
66    {
67      einfo (_("%F%P: can not create BFD: %E\n"));
68      return;
69    }
70
71  stub_file->the_bfd->flags |= BFD_LINKER_CREATED;
72  ldlang_add_file (stub_file);
73}
74
75
76struct hook_stub_info
77{
78  lang_statement_list_type add;
79  asection *input_section;
80};
81
82/* Traverse the linker tree to find the spot where the stub goes.  */
83
84static bool
85hook_in_stub (struct hook_stub_info *info, lang_statement_union_type **lp,
86                bool afterp)
87{
88  lang_statement_union_type *l;
89  bool ret;
90
91  for (; (l = *lp) != NULL; lp = &l->header.next)
92    {
93      switch (l->header.type)
94          {
95          case lang_constructors_statement_enum:
96            ret = hook_in_stub (info, &constructor_list.head, afterp);
97            if (ret)
98              return ret;
99            break;
100
101          case lang_output_section_statement_enum:
102            ret = hook_in_stub (info,
103                                    &l->output_section_statement.children.head,
104                                    afterp);
105            if (ret)
106              return ret;
107            break;
108
109          case lang_wild_statement_enum:
110            ret = hook_in_stub (info, &l->wild_statement.children.head, afterp);
111            if (ret)
112              return ret;
113            break;
114
115          case lang_group_statement_enum:
116            ret = hook_in_stub (info, &l->group_statement.children.head, afterp);
117            if (ret)
118              return ret;
119            break;
120
121          case lang_input_section_enum:
122            if (l->input_section.section == info->input_section)
123              {
124                /* We've found our section.  Insert the stub immediately
125                     before or after its associated input section.  */
126                if (afterp)
127                    {
128                      *(info->add.tail) = l->header.next;
129                      l->header.next = info->add.head;
130                    }
131                else
132                    {
133                      *lp = info->add.head;
134                      *(info->add.tail) = l;
135                    }
136                return true;
137              }
138            break;
139
140          case lang_data_statement_enum:
141          case lang_reloc_statement_enum:
142          case lang_object_symbols_statement_enum:
143          case lang_output_statement_enum:
144          case lang_target_statement_enum:
145          case lang_input_statement_enum:
146          case lang_assignment_statement_enum:
147          case lang_padding_statement_enum:
148          case lang_address_statement_enum:
149          case lang_fill_statement_enum:
150            break;
151
152          default:
153            FAIL ();
154            break;
155          }
156    }
157  return false;
158}
159
160/* Call-back for elf32_nios2_size_stubs.  */
161
162/* Create a new stub section, and arrange for it to be linked
163   immediately before or after INPUT_SECTION, according to AFTERP.  */
164
165static asection *
166nios2elf_add_stub_section (const char *stub_sec_name, asection *input_section,
167                                 bool afterp)
168{
169  asection *stub_sec;
170  flagword flags;
171  asection *output_section;
172  const char *secname;
173  lang_output_section_statement_type *os;
174  struct hook_stub_info info;
175
176  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
177             | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
178  stub_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
179                                                             stub_sec_name, flags);
180  if (stub_sec == NULL)
181    goto err_ret;
182
183  output_section = input_section->output_section;
184  secname = bfd_section_name (output_section);
185  os = lang_output_section_find (secname);
186
187  info.input_section = input_section;
188  lang_list_init (&info.add);
189  lang_add_section (&info.add, stub_sec, NULL, NULL, os);
190
191  if (info.add.head == NULL)
192    goto err_ret;
193
194  if (hook_in_stub (&info, &os->children.head, afterp))
195    return stub_sec;
196
197 err_ret:
198  einfo (_("%X%P: can not make stub section: %E\n"));
199  return NULL;
200}
201
202
203/* Another call-back for elf32_nios2_size_stubs.  */
204
205static void
206nios2elf_layout_sections_again (void)
207{
208  /* If we have changed sizes of the stub sections, then we need
209     to recalculate all the section offsets.  This may mean we need to
210     add even more stubs.  */
211  ldelf_map_segments (true);
212  need_laying_out = -1;
213}
214
215
216static void
217build_section_lists (lang_statement_union_type *statement)
218{
219  if (statement->header.type == lang_input_section_enum)
220    {
221      asection *i = statement->input_section.section;
222
223      if (i->sec_info_type != SEC_INFO_TYPE_JUST_SYMS
224            && (i->flags & SEC_EXCLUDE) == 0
225            && i->output_section != NULL
226            && i->output_section->owner == link_info.output_bfd)
227          {
228            nios2_elf32_next_input_section (&link_info, i);
229          }
230    }
231}
232
233
234/* For Nios II we use this opportunity to build linker stubs.  */
235
236static void
237gld${EMULATION_NAME}_after_allocation (void)
238{
239  int ret;
240
241  /* bfd_elf_discard_info just plays with data and debugging sections,
242     ie. doesn't affect code size, so we can delay resizing the
243     sections.  It's likely we'll resize everything in the process of
244     adding stubs.  */
245  ret = bfd_elf_discard_info (link_info.output_bfd, &link_info);
246  if (ret < 0)
247    {
248      einfo (_("%X%P: .eh_frame/.stab edit: %E\n"));
249      return;
250    }
251  else if (ret > 0)
252    need_laying_out = 1;
253
254  /* If generating a relocatable output file, then we don't
255     have to examine the relocs.  */
256  if (stub_file != NULL
257      && !bfd_link_relocatable (&link_info)
258      && RELAXATION_ENABLED)
259    {
260      ret = nios2_elf32_setup_section_lists (link_info.output_bfd, &link_info);
261      if (ret != 0)
262          {
263            if (ret < 0)
264              {
265                einfo (_("%X%P: can not size stub section: %E\n"));
266                return;
267              }
268
269            lang_for_each_statement (build_section_lists);
270
271            /* Call into the BFD backend to do the real work.  */
272            if (! nios2_elf32_size_stubs (link_info.output_bfd,
273                                                  stub_file->the_bfd,
274                                                  &link_info,
275                                                  &nios2elf_add_stub_section,
276                                                  &nios2elf_layout_sections_again))
277              {
278                einfo (_("%X%P: can not size stub section: %E\n"));
279                return;
280              }
281          }
282    }
283
284  if (need_laying_out != -1)
285    ldelf_map_segments (need_laying_out);
286
287  if (!bfd_link_relocatable (&link_info) && RELAXATION_ENABLED)
288    {
289      /* Now build the linker stubs.  */
290      if (stub_file != NULL && stub_file->the_bfd->sections != NULL)
291          {
292            if (! nios2_elf32_build_stubs (&link_info))
293              einfo (_("%X%P: can not build stubs: %E\n"));
294          }
295    }
296}
297
298EOF
299
300
301# Put these extra nios2elf routines in ld_${EMULATION_NAME}_emulation
302#
303LDEMUL_AFTER_ALLOCATION=gld${EMULATION_NAME}_after_allocation
304LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=nios2elf_create_output_section_statements
305