ld: add support of QNX stack arguments for aarch64nto

QNX is handling the stack argument using a .note section. Generate it
according to ELF argument -zexecstack, -zstack-size and a new NTO
argument --lazy-stack. Another NTO argument --stack mimicking
-zstack-size is added in order to ensure compatibility with previously
made NTO linkers.
This requires a new emultempl nto.em which is applied above the default
${ARCH}elf.em.

ld/ChangeLog:

	* emulparams/aarch64nto.sh: Move to nto.em.
	* emultempl/nto.em: New file.
	* testsuite/ld-aarch64/aarch64-nto.exp: New test.
	* testsuite/ld-aarch64/nto-stack-note-1.d: New test.
	* testsuite/ld-aarch64/nto-stack-note-2.d: New test.
	* testsuite/ld-aarch64/start.s: New test.

ld/emulparams/aarch64nto.sh

@@ -10,7 +10,7 @@ LITTLE_OUTPUT_FORMAT="elf64-littleaarch64"
 NO_REL_RELOCS=yes
 
 TEMPLATE_NAME=elf
-EXTRA_EM_FILE=aarch64elf
+EXTRA_EM_FILE=nto
 
 GENERATE_SHLIB_SCRIPT=yes
 GENERATE_PIE_SCRIPT=yes

ld/emultempl/nto.em

@@ -0,0 +1,163 @@
+# This shell script emits a C file. -*- C -*-
+#   Copyright 2023 Free Software Foundation, Inc.
+#
+# This file is part of GLD, the Gnu Linker.
+#
+# 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 2 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 Neutrino
+# specific routines.
+
+# NTO templates aims to refine the default ${ARCH}elf.em template.
+. "${srcdir}/emultempl/${ARCH}elf.em"
+
+cat >>e${EMULATION_NAME}.c <<EOF
+
+#include "elf/internal.h"
+#include "elf/common.h"
+#include "elf-bfd.h"
+#include "../bfd/libbfd.h"
+
+bool nto_lazy_stack = false;
+struct nto_stack_note
+{
+  unsigned char stacksize[4];
+  unsigned char stackalloc[4];
+  unsigned char execstack[4];
+};
+
+/* Generate the QNT_STACK .note section.  */
+static void
+nto_add_note_section (void) {
+  asection *note_sec;
+  flagword flags;
+  Elf_External_Note *e_note;
+  bfd_size_type size, h_size;
+  struct nto_stack_note *n_note;
+
+  /* Don't create a note if the stack size isn't provided.  */
+  if (link_info.stacksize <= 0)
+    return;
+
+  /* As ${ARCH}elf.em is imported and ${ARCH}_elf_create_output_section_statements
+     is called before this function, stub_file should already be defined.  */
+  if (!stub_file)
+    {
+      einfo (_("%F%P: cannot create .note section in stub BFD.\n"));
+      return;
+    }
+
+  if (nto_lazy_stack && !link_info.stacksize)
+    {
+      einfo (_("%F%P: error: --lazy-stack must follow -zstack-size=<size>\n"));
+      return;
+    }
+
+  flags = (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_HAS_CONTENTS
+	   | SEC_IN_MEMORY | SEC_LINKER_CREATED);
+  note_sec = bfd_make_section_anyway_with_flags (stub_file->the_bfd, ".note", flags);
+  if (! note_sec)
+    {
+      einfo (_("%F%P: failed to create .note section\n"));
+      return;
+    }
+
+  size = offsetof (Elf_External_Note, name[sizeof "QNX"]);
+  size = (size + 3) & -(bfd_size_type) 4;
+  h_size = size;
+  size += sizeof (struct nto_stack_note);
+  note_sec->size = size;
+
+  elf_section_type (note_sec) = SHT_NOTE;
+  note_sec->contents = xmalloc (note_sec->size);
+  e_note = (Elf_External_Note *) note_sec->contents;
+  bfd_h_put_32 (stub_file->the_bfd, sizeof "QNX", &e_note->namesz);
+  bfd_h_put_32 (stub_file->the_bfd, sizeof (struct nto_stack_note), &e_note->descsz);
+  bfd_h_put_32 (stub_file->the_bfd, QNT_STACK, &e_note->type);
+  memcpy (e_note->name, "QNX", sizeof "QNX");
+
+
+  /* Generate .note content.*/
+  n_note = (struct nto_stack_note *) (note_sec->contents + h_size);
+  bfd_h_put_32 (stub_file->the_bfd, link_info.stacksize, &n_note->stacksize);
+
+  if (nto_lazy_stack)
+    bfd_h_put_32 (stub_file->the_bfd, 4096, &n_note->stackalloc);
+  else
+    bfd_h_put_32 (stub_file->the_bfd, link_info.stacksize, &n_note->stackalloc);
+
+  if (link_info.execstack != link_info.noexecstack && link_info.execstack)
+    bfd_h_put_32 (stub_file->the_bfd, 0, &n_note->execstack);
+  else
+    bfd_h_put_32 (stub_file->the_bfd, 1, &n_note->execstack);
+
+}
+
+static void
+nto_create_output_section_statements (void)
+{
+  ${ARCH}_elf_create_output_section_statements ();
+  nto_add_note_section();
+}
+
+EOF
+
+# Define some shell vars to insert bits of code into the standard elf
+# parse_args and list_options functions.
+#
+
+PARSE_AND_LIST_PROLOGUE=${PARSE_AND_LIST_PROLOGUE}'
+enum nto_options
+{
+  OPTION_STACK = 500,
+  OPTION_LAZY_STACK,
+};
+'
+
+PARSE_AND_LIST_LONGOPTS=${PARSE_AND_LIST_LONGOPTS}'
+  { "stack", required_argument, NULL, OPTION_STACK },
+  { "lazy-stack", no_argument, NULL, OPTION_LAZY_STACK },
+'
+
+PARSE_AND_LIST_OPTIONS=${PARSE_AND_LIST_OPTIONS}'
+  fprintf (file, _("\
+  --stack <size>              Set size of the initial stack\n\
+  --lazy-stack		      Set lazy allocation of stack\n\
+"));
+'
+
+PARSE_AND_LIST_ARGS_CASES=${PARSE_AND_LIST_ARGS_CASES}'
+    case OPTION_STACK:
+      {
+        char *end;
+        link_info.stacksize = strtoul (optarg, &end, 0);
+        if (*end || link_info.stacksize < 0)
+          einfo (_("%F%P: invalid stack size `%s'\''\n"), optarg + 11);
+        if (!link_info.stacksize)
+          /* Use -1 for explicit no-stack, because zero means
+             'default'.   */
+          link_info.stacksize = -1;
+        break;
+      }
+    case OPTION_LAZY_STACK:
+      nto_lazy_stack = true;
+      break;
+'
+
+# Put these extra Neutrino routines in ld_${EMULATION_NAME}_emulation
+#
+
+LDEMUL_CREATE_OUTPUT_SECTION_STATEMENTS=nto_create_output_section_statements

ld/testsuite/ld-aarch64/aarch64-nto.exp

@@ -0,0 +1,28 @@
+
+# Expect script for various AARCH64 NTO tests.
+# Copyright (C) 2009-2022 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.
+
+# Exclude non-aarch64-NTO targets.
+if { ![istarget "aarch64*-*-nto*"] } {
+    return
+}
+
+run_dump_test "nto-stack-note-1"
+run_dump_test "nto-stack-note-2"

ld/testsuite/ld-aarch64/nto-stack-note-1.d

@@ -0,0 +1,12 @@
+#name: nto-stack-note-1
+#source: start.s
+#as:
+#ld: -z stack-size=0x10000
+#readelf: -n
+
+Displaying notes found in: .note
+[ 	]+Owner[ 	]+Data size[ 	]+Description
+  QNX                  0x0000000c	QNX stack
+   Stack Size: 0x10000
+   Stack allocated: 10000
+   Executable: no

ld/testsuite/ld-aarch64/nto-stack-note-2.d

@@ -0,0 +1,12 @@
+#name: nto-stack-note-2
+#source: start.s
+#as:
+#ld: -z stack-size=0x10000 --lazy-stack -z execstack
+#readelf: -n
+
+Displaying notes found in: .note
+[ 	]+Owner[ 	]+Data size[ 	]+Description
+  QNX                  0x0000000c	QNX stack
+   Stack Size: 0x10000
+   Stack allocated: 1000
+   Executable: yes

ld/testsuite/ld-aarch64/start.s

@@ -0,0 +1,4 @@
+        .global _start
+        .text
+_start:
+        nop