# This shell script emits a C file. -*- C -*-

# This shell script emits a C file. -*- C -*-
# Copyright (C) 2006-2025 Free Software Foundation, Inc.
#
# This file is part of the GNU Binutils.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
# MA 02110-1301, USA.

# This file is sourced from elf.em, and defines extra avr-elf specific
# routines. It is used to generate the trampolines for the avr6 family
# of devices where one needs to address the issue that it is not possible
# to reach the whole program memory by using 16 bit pointers.

fragment <<EOF

#include "elf32-avr.h"
#include "ldctor.h"
#include "elf/avr.h"

/* The fake file and it's corresponding section meant to hold
the linker stubs if needed. */

static lang_input_statement_type *stub_file;
static asection *avr_stub_section;

/* Variables set by the command-line parameters and transferred
to the bfd without use of global shared variables. */

static bool avr_no_stubs = false;
static bool avr_debug_relax = false;
static bool avr_debug_stubs = false;
static bool avr_replace_call_ret_sequences = true;
static bfd_vma avr_pc_wrap_around = 0x10000000;

/* Transfers information to the bfd frontend. */

static void
avr_elf_set_global_bfd_parameters (void)
{
elf32_avr_setup_params (& link_info,
stub_file->the_bfd,
avr_stub_section,
avr_no_stubs,
avr_debug_stubs,
avr_debug_relax,
avr_pc_wrap_around,
avr_replace_call_ret_sequences);
}

/* Makes a conservative estimate of the trampoline section size that could
be corrected later on. */

static void
avr_elf_${EMULATION_NAME}_before_allocation (void)
{
int ret;

gld${EMULATION_NAME}_before_allocation ();

if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
{
avr_no_stubs = true;
return;
}

/* We only need stubs for avr6, avrxmega6, and avrxmega7. */
if (strcmp ("${EMULATION_NAME}", "avr6") != 0
&& strcmp ("${EMULATION_NAME}", "avrxmega6") != 0
&& strcmp ("${EMULATION_NAME}", "avrxmega7") != 0)
avr_no_stubs = true;

avr_elf_set_global_bfd_parameters ();

/* If generating a relocatable output file, then
we don't have to generate the trampolines. */
if (bfd_link_relocatable (&link_info))
avr_no_stubs = true;

if (avr_no_stubs)
return;

ret = elf32_avr_setup_section_lists (link_info.output_bfd, &link_info);

if (ret < 0)
einfo (_("%X%P: can not setup the input section list: %E\n"));

if (ret <= 0)
return;

/* Call into the BFD backend to do the real "stub"-work. */
if (! elf32_avr_size_stubs (link_info.output_bfd, &link_info, true))
einfo (_("%X%P: can not size stub section: %E\n"));
}

/* This is called before the input files are opened. We create a new
fake input file to hold the stub section and generate the section itself. */

static void
avr_elf_create_output_section_statements (void)
{
flagword flags;

if (bfd_get_flavour (link_info.output_bfd) != bfd_target_elf_flavour)
{
fatal (_("%P: error: cannot change output format "
"whilst linking %s binaries\n"), "AVR");
return;
}

stub_file = lang_add_input_file ("linker stubs",
lang_input_file_is_fake_enum,
NULL);

stub_file->the_bfd = bfd_create ("linker stubs", link_info.output_bfd);
if (stub_file->the_bfd == NULL
|| !bfd_set_arch_mach (stub_file->the_bfd,
bfd_get_arch (link_info.output_bfd),
bfd_get_mach (link_info.output_bfd)))
{
einfo (_("%X%P: can not create stub BFD: %E\n"));
return;
}
stub_file->the_bfd->flags |= BFD_LINKER_CREATED;

/* Now we add the stub section. */

flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE
| SEC_HAS_CONTENTS | SEC_RELOC | SEC_IN_MEMORY | SEC_KEEP);
avr_stub_section = bfd_make_section_anyway_with_flags (stub_file->the_bfd,
".trampolines",
flags);
if (avr_stub_section == NULL)
goto err_ret;

avr_stub_section->alignment_power = 1;

ldlang_add_file (stub_file);

return;

err_ret:
einfo (_("%X%P: can not make stub section: %E\n"));
return;
}

/* Re-calculates the size of the stubs so that we won't waste space. */

static void
avr_elf_after_allocation (void)
{
if (!avr_no_stubs && ! RELAXATION_ENABLED)
{
/* If relaxing, elf32_avr_size_stubs will be called from
elf32_avr_relax_section. */
if (!elf32_avr_size_stubs (link_info.output_bfd, &link_info, true))
einfo (_("%X%P: can not size stub section: %E\n"));
}

gld${EMULATION_NAME}_after_allocation ();

/* Now build the linker stubs. */
if (!avr_no_stubs)
{
if (!elf32_avr_build_stubs (&link_info))
einfo (_("%X%P: can not build stubs: %E\n"));
}
}

static void
avr_elf_before_parse (void)
{
/* Don't create a demand-paged executable, since this feature isn't
meaningful in AVR. */
config.magic_demand_paged = false;

gld${EMULATION_NAME}_before_parse ();
}

static void
avr_finish (void)
{
bfd *abfd;
bool avr_link_relax;

if (bfd_link_relocatable (&link_info))
{
avr_link_relax = true;
for (abfd = link_info.input_bfds; abfd != NULL; abfd = abfd->link.next)
{
/* Don't let the linker stubs prevent the final object being
marked as link-relax ready. */
if ((elf_elfheader (abfd)->e_flags
& EF_AVR_LINKRELAX_PREPARED) == 0
&& abfd != stub_file->the_bfd)
{
avr_link_relax = false;
break;
}
}
}
else
{
avr_link_relax = RELAXATION_ENABLED;
}

abfd = link_info.output_bfd;

if (bfd_get_flavour (link_info.output_bfd) == bfd_target_elf_flavour)
{
if (avr_link_relax)
elf_elfheader (abfd)->e_flags |= EF_AVR_LINKRELAX_PREPARED;
else
elf_elfheader (abfd)->e_flags &= ~EF_AVR_LINKRELAX_PREPARED;
}

ldelf_finish ();
}
EOF

PARSE_AND_LIST_LONGOPTS='
{ "no-call-ret-replacement", no_argument,
NULL, OPTION_NO_CALL_RET_REPLACEMENT},
{ "pmem-wrap-around", required_argument,
NULL, OPTION_PMEM_WRAP_AROUND},
{ "no-stubs", no_argument,
NULL, OPTION_NO_STUBS},
{ "debug-stubs", no_argument,
NULL, OPTION_DEBUG_STUBS},
{ "debug-relax", no_argument,
NULL, OPTION_DEBUG_RELAX},
'

PARSE_AND_LIST_OPTIONS='
fprintf (file, _(" --pmem-wrap-around=<val> "
"Make the linker relaxation machine assume that a\n"
" "
" program counter wrap-around occurs at address\n"
" "
" <val>. Supported values: 8k, 16k, 32k and 64k.\n"));
fprintf (file, _(" --no-call-ret-replacement "
"The relaxation machine normally will\n"
" "
" substitute two immediately following call/ret\n"
" "
" instructions by a single jump instruction.\n"
" "
" This option disables this optimization.\n"));
fprintf (file, _(" --no-stubs "
"If the linker detects to attempt to access\n"
" "
" an instruction beyond 128k by a reloc that\n"
" "
" is limited to 128k max, it inserts a jump\n"
" "
" stub. You can de-active this with this switch.\n"));
fprintf (file, _(" --debug-stubs "
"Used for debugging avr-ld.\n"));
fprintf (file, _(" --debug-relax "
"Used for debugging avr-ld.\n"));
'

PARSE_AND_LIST_ARGS_CASES='

case OPTION_PMEM_WRAP_AROUND:
{
/* This variable is defined in the bfd library. */
if ((!strcmp (optarg,"32k")) || (!strcmp (optarg,"32K")))
avr_pc_wrap_around = 32768;
else if ((!strcmp (optarg,"8k")) || (!strcmp (optarg,"8K")))
avr_pc_wrap_around = 8192;
else if ((!strcmp (optarg,"16k")) || (!strcmp (optarg,"16K")))
avr_pc_wrap_around = 16384;
else if ((!strcmp (optarg,"64k")) || (!strcmp (optarg,"64K")))
avr_pc_wrap_around = 0x10000;
else
return false;
}
break;

case OPTION_DEBUG_STUBS:
avr_debug_stubs = true;
break;

case OPTION_DEBUG_RELAX:
avr_debug_relax = true;
break;

case OPTION_NO_STUBS:
avr_no_stubs = true;
break;

case OPTION_NO_CALL_RET_REPLACEMENT:
{
/* This variable is defined in the bfd library. */
avr_replace_call_ret_sequences = false;
}
break;
'

#
# Put these extra avr-elf routines in ld_${EMULATION_NAME}_emulation
#
LDEMUL_BEFORE_PARSE=avr_elf_before_parse
LDEMUL_BEFORE_ALLOCATION=avr_elf_${EMULATION_NAME}_before_allocation
LDEMUL_AFTER_ALLOCATION=avr_elf_after_allocation
LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=avr_elf_create_output_section_statements
LDEMUL_FINISH=avr_finish