1# This shell script emits a C file. -*- C -*-
2#   Copyright (C) 2006-2016 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 elf32.em, and defines extra avr-elf specific
23# routines.  It is used to generate the trampolines for the avr6 family
24# of devices where one needs to address the issue that it is not possible
25# to reach the whole program memory by using 16 bit pointers.
26
27fragment <<EOF
28
29#include "elf32-avr.h"
30#include "ldctor.h"
31#include "elf/avr.h"
32
33/* The fake file and it's corresponding section meant to hold
34   the linker stubs if needed.  */
35
36static lang_input_statement_type *stub_file;
37static asection *avr_stub_section;
38
39/* Variables set by the command-line parameters and transfered
40   to the bfd without use of global shared variables.  */
41
42static bfd_boolean avr_no_stubs = FALSE;
43static bfd_boolean avr_debug_relax = FALSE;
44static bfd_boolean avr_debug_stubs = FALSE;
45static bfd_boolean avr_replace_call_ret_sequences = TRUE;
46static bfd_vma avr_pc_wrap_around = 0x10000000;
47
48/* Transfers information to the bfd frontend.  */
49
50static void
51avr_elf_set_global_bfd_parameters (void)
52{
53  elf32_avr_setup_params (& link_info,
54                          stub_file->the_bfd,
55                          avr_stub_section,
56                          avr_no_stubs,
57                          avr_debug_stubs,
58                          avr_debug_relax,
59                          avr_pc_wrap_around,
60                          avr_replace_call_ret_sequences);
61}
62
63
64/* Makes a conservative estimate of the trampoline section size that could
65   be corrected later on.  */
66
67static void
68avr_elf_${EMULATION_NAME}_before_allocation (void)
69{
70  int ret;
71
72  gld${EMULATION_NAME}_before_allocation ();
73
74  /* We only need stubs for avr6, avrxmega6, and avrxmega7. */
75  if (strcmp ("${EMULATION_NAME}","avr6")
76      && strcmp ("${EMULATION_NAME}","avrxmega6")
77      && strcmp ("${EMULATION_NAME}","avrxmega7") )
78    avr_no_stubs = TRUE;
79
80  avr_elf_set_global_bfd_parameters ();
81
82  /* If generating a relocatable output file, then
83     we don't  have to generate the trampolines.  */
84  if (bfd_link_relocatable (&link_info))
85    avr_no_stubs = TRUE;
86
87  if (avr_no_stubs)
88    return;
89
90  ret = elf32_avr_setup_section_lists (link_info.output_bfd, &link_info);
91
92  if (ret < 0)
93    einfo ("%X%P: can not setup the input section list: %E\n");
94
95  if (ret <= 0)
96    return;
97
98  /* Call into the BFD backend to do the real "stub"-work.  */
99  if (! elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
100    einfo ("%X%P: can not size stub section: %E\n");
101}
102
103/* This is called before the input files are opened.  We create a new
104   fake input file to hold the stub section and generate the section itself.  */
105
106static void
107avr_elf_create_output_section_statements (void)
108{
109  flagword flags;
110
111  stub_file = lang_add_input_file ("linker stubs",
112                                   lang_input_file_is_fake_enum,
113                                   NULL);
114
115  stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
116  if (stub_file->the_bfd == NULL
117      || !bfd_set_arch_mach (stub_file->the_bfd,
118                             bfd_get_arch (link_info.output_bfd),
119                             bfd_get_mach (link_info.output_bfd)))
120    {
121      einfo ("%X%P: can not create stub BFD %E\n");
122      return;
123    }
124
125  /* Now we add the stub section.  */
126
127  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
128           | SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
129  avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
130							 ".trampolines",
131							 flags);
132  if (avr_stub_section == NULL)
133    goto err_ret;
134
135  avr_stub_section->alignment_power = 1;
136
137  ldlang_add_file (stub_file);
138
139  return;
140
141  err_ret:
142   einfo ("%X%P: can not make stub section: %E\n");
143   return;
144}
145
146/* Re-calculates the size of the stubs so that we won't waste space.  */
147
148static void
149avr_elf_after_allocation (void)
150{
151  if (!avr_no_stubs && ! RELAXATION_ENABLED)
152    {
153      /* If relaxing, elf32_avr_size_stubs will be called from
154	 elf32_avr_relax_section.  */
155      if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, TRUE))
156	einfo ("%X%P: can not size stub section: %E\n");
157    }
158
159  gld${EMULATION_NAME}_after_allocation ();
160
161  /* Now build the linker stubs.  */
162  if (!avr_no_stubs)
163    {
164      if (!elf32_avr_build_stubs (&link_info))
165	einfo ("%X%P: can not build stubs: %E\n");
166    }
167}
168
169static void
170avr_elf_before_parse (void)
171{
172  /* Don't create a demand-paged executable, since this feature isn't
173     meaningful in AVR. */
174  config.magic_demand_paged = FALSE;
175
176  gld${EMULATION_NAME}_before_parse ();
177}
178
179static void
180avr_finish (void)
181{
182  bfd *abfd;
183  bfd_boolean avr_link_relax;
184
185  if (bfd_link_relocatable (&link_info))
186    {
187      avr_link_relax = TRUE;
188      for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
189        {
190          /* Don't let the linker stubs prevent the final object being
191             marked as link-relax ready.  */
192          if ((elf_elfheader (abfd)->e_flags
193               & EF_AVR_LINKRELAX_PREPARED) == 0
194              && abfd != stub_file->the_bfd)
195            {
196              avr_link_relax = FALSE;
197              break;
198            }
199        }
200    }
201  else
202    {
203      avr_link_relax = RELAXATION_ENABLED;
204    }
205
206  abfd = link_info.output_bfd;
207  if (avr_link_relax)
208    elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED;
209  else
210    elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED;
211
212  finish_default ();
213}
214EOF
215
216
217PARSE_AND_LIST_PROLOGUE='
218
219#define OPTION_NO_CALL_RET_REPLACEMENT 301
220#define OPTION_PMEM_WRAP_AROUND        302
221#define OPTION_NO_STUBS                303
222#define OPTION_DEBUG_STUBS             304
223#define OPTION_DEBUG_RELAX             305
224'
225
226PARSE_AND_LIST_LONGOPTS='
227  { "no-call-ret-replacement", no_argument,
228     NULL, OPTION_NO_CALL_RET_REPLACEMENT},
229  { "pmem-wrap-around", required_argument,
230    NULL, OPTION_PMEM_WRAP_AROUND},
231  { "no-stubs", no_argument,
232    NULL, OPTION_NO_STUBS},
233  { "debug-stubs", no_argument,
234    NULL, OPTION_DEBUG_STUBS},
235  { "debug-relax", no_argument,
236    NULL, OPTION_DEBUG_RELAX},
237'
238
239PARSE_AND_LIST_OPTIONS='
240  fprintf (file, _("  --pmem-wrap-around=<val>    "
241		   "Make the linker relaxation machine assume that a\n"
242		   "                              "
243		   "  program counter wrap-around occures at address\n"
244		   "                              "
245		   "  <val>.  Supported values: 8k, 16k, 32k and 64k.\n"));
246  fprintf (file, _("  --no-call-ret-replacement   "
247		   "The relaxation machine normally will\n"
248		   "                              "
249		   "  substitute two immediately following call/ret\n"
250		   "                              "
251		   "  instructions by a single jump instruction.\n"
252		   "                              "
253		   "  This option disables this optimization.\n"));
254  fprintf (file, _("  --no-stubs                  "
255		   "If the linker detects to attempt to access\n"
256		   "                              "
257		   "  an instruction beyond 128k by a reloc that\n"
258		   "                              "
259		   "  is limited to 128k max, it inserts a jump\n"
260		   "                              "
261		   "  stub. You can de-active this with this switch.\n"));
262  fprintf (file, _("  --debug-stubs               "
263		   "Used for debugging avr-ld.\n"));
264  fprintf (file, _("  --debug-relax               "
265		   "Used for debugging avr-ld.\n"));
266'
267
268PARSE_AND_LIST_ARGS_CASES='
269
270    case OPTION_PMEM_WRAP_AROUND:
271      {
272        /* This variable is defined in the bfd library.  */
273        if ((!strcmp (optarg,"32k"))      || (!strcmp (optarg,"32K")))
274          avr_pc_wrap_around = 32768;
275        else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K")))
276          avr_pc_wrap_around = 8192;
277        else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
278          avr_pc_wrap_around = 16384;
279        else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
280          avr_pc_wrap_around = 0x10000;
281        else
282          return FALSE;
283      }
284      break;
285
286    case OPTION_DEBUG_STUBS:
287      avr_debug_stubs = TRUE;
288      break;
289
290    case OPTION_DEBUG_RELAX:
291      avr_debug_relax = TRUE;
292      break;
293
294    case OPTION_NO_STUBS:
295      avr_no_stubs = TRUE;
296      break;
297
298    case OPTION_NO_CALL_RET_REPLACEMENT:
299      {
300        /* This variable is defined in the bfd library.  */
301        avr_replace_call_ret_sequences = FALSE;
302      }
303      break;
304'
305
306#
307# Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
308#
309LDEMUL_BEFORE_PARSE=avr_elf_before_parse
310LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
311LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
312LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements
313LDEMUL_FINISH=avr_finish
314