Fixes for the magic number used in PDP11 AOUT binaries.

	PR ld/25677
include	* aout/aout64.h (N_DATADDR): Add IMAGIC case.

bfd	* pdp11.c: Add implementation of --imagic option.
	(adjust_o_magic): Fix objcopy --extract-symbol test.
	* libaout.h (enum aout_magic): Add i_magic.

ld	* emulparams/pdp11.sh (SCRIPT_NAME): Change to pdp11.
	(EXTRA_EM_FILE): New, add emulation file pdp11.
	* scripttempl/pdp11.sc: New, derived from aout.sc without
	irrelevant input sections.
	* emultempl/pdp11.em (_add_options, _handle_option)
	(_list_options): New. Add options -z, --imagic for pdp11-aout.
	(_before_parse): Make --omagic be default instead of --nmagic.
	(_get_script): Modify special-case linker script for --imagic.
	* lexsup.c (parse_args): Explictly set config.text_read_only for -n.
	* ld.texi (Options): Add documentation of PDP11-specific options.
	(Options): Fix unrelated typo to --no-compact-branches.
	* gen-doc.texi: @set PDP11.
	* testsuite/ld-pdp11/pdp11.exp: New, start pdp11 testing.
	* testsuite/ld-pdp11/sections.s: New, source for options tests.
	* testsuite/ld-pdp11/imagic.d: New, test --imagic format.
	* testsuite/ld-pdp11/imagicz.d: New, test -z (imagic) format.
	* testsuite/ld-pdp11/nmagic.d: New, test --nmagic format.
	* testsuite/ld-pdp11/omagic.d: New, test --omagic format.

1 files changed, 132 insertions, 0 deletions

diff --git a/ld/emultempl/pdp11.em b/ld/emultempl/pdp11.em
new file mode 100644
index 0000000..d18a420
--- /dev/null
+++ b/ld/emultempl/pdp11.em
@@ -0,0 +1,132 @@
+# This shell script emits a C file. -*- C -*-
+#   Copyright (C) 2006-2020 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.
+
+fragment <<EOF
+
+/* --- \begin{pdp11.em} */
+#include "getopt.h"
+
+static void
+gld${EMULATION_NAME}_before_parse (void)
+{
+  ldfile_set_output_arch ("`echo ${ARCH}`", bfd_arch_unknown);
+  /* for PDP11 Unix compatibility, default to --omagic */
+  config.magic_demand_paged = FALSE;
+  config.text_read_only = FALSE;
+}
+
+/* PDP11 specific options.  */
+#define OPTION_IMAGIC 301
+
+static void
+gld${EMULATION_NAME}_add_options
+  (int ns ATTRIBUTE_UNUSED,
+   char **shortopts,
+   int nl,
+   struct option **longopts,
+   int nrl ATTRIBUTE_UNUSED,
+   struct option **really_longopts ATTRIBUTE_UNUSED)
+{
+  static const char xtra_short[] = "z";
+  static const struct option xtra_long[] =
+  {
+    {"imagic", no_argument, NULL, OPTION_IMAGIC},
+    {NULL, no_argument, NULL, 0}
+  };
+
+  *shortopts = (char *) xrealloc (*shortopts, ns + sizeof (xtra_short));
+  memcpy (*shortopts + ns, &xtra_short, sizeof (xtra_short));
+  *longopts
+    = xrealloc (*longopts, nl * sizeof (struct option) + sizeof (xtra_long));
+  memcpy (*longopts + nl, &xtra_long, sizeof (xtra_long));
+}
+
+static void
+gld${EMULATION_NAME}_list_options (FILE *file)
+{
+  fprintf (file, _("  -N, --omagic   Do not make text readonly, do not page align data (default)\n"));
+  fprintf (file, _("  -n, --nmagic   Make text readonly, align data to next page\n"));
+  fprintf (file, _("  -z, --imagic   Make text readonly, separate instruction and data spaces\n"));
+  fprintf (file, _("  --no-omagic    Equivalent to --nmagic\n"));
+}
+
+static bfd_boolean
+gld${EMULATION_NAME}_handle_option (int optc)
+{
+  switch (optc)
+    {
+    default:
+      return FALSE;
+
+    case 'z':
+    case OPTION_IMAGIC:
+      link_info.separate_code = 1;
+      /* The --imagic format causes the .text and .data sections to occupy the
+	 same memory addresses in separate spaces, so don't check overlap. */
+      command_line.check_section_addresses = 0;
+      break;
+    }
+
+  return TRUE;
+}
+
+/* We need a special case to prepare an additional linker script for option
+ * --imagic where the .data section starts at address 0 rather than directly
+ * following the .text section or being aligned to the next page after the
+ * .text section. */
+static char *
+gld${EMULATION_NAME}_get_script (int *isfile)
+EOF
+# Scripts compiled in.
+# sed commands to quote an ld script as a C string.
+sc="-f stringify.sed"
+
+fragment <<EOF
+{
+  *isfile = 0;
+
+  if (bfd_link_relocatable (&link_info) && config.build_constructors)
+    return
+EOF
+sed $sc ldscripts/${EMULATION_NAME}.xu			>> e${EMULATION_NAME}.c
+echo '  ; else if (bfd_link_relocatable (&link_info)) return' >> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xr			>> e${EMULATION_NAME}.c
+echo '  ; else if (link_info.separate_code) return'	>> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xn | \
+  sed -e "s/ALIGN($TARGET_PAGE_SIZE)/0/"		>> e${EMULATION_NAME}.c
+echo '  ; else if (!config.text_read_only) return'	>> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xbn			>> e${EMULATION_NAME}.c
+echo '  ; else if (!config.magic_demand_paged) return'	>> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.xn			>> e${EMULATION_NAME}.c
+echo '  ; else return'					>> e${EMULATION_NAME}.c
+sed $sc ldscripts/${EMULATION_NAME}.x			>> e${EMULATION_NAME}.c
+echo '; }'						>> e${EMULATION_NAME}.c
+
+fragment <<EOF
+
+/* --- \end{pdp11.em} */
+
+EOF
+
+LDEMUL_BEFORE_PARSE=gld"$EMULATION_NAME"_before_parse
+LDEMUL_ADD_OPTIONS=gld"$EMULATION_NAME"_add_options
+LDEMUL_HANDLE_OPTION=gld"$EMULATION_NAME"_handle_option
+LDEMUL_LIST_OPTIONS=gld"$EMULATION_NAME"_list_options
+LDEMUL_GET_SCRIPT=gld"$EMULATION_NAME"_get_script