sim/common/sim-options.c

/* Simulator option handling.
   Copyright (C) 1996-2019 Free Software Foundation, Inc.
   Contributed by Cygnus Support.

This file is part of GDB, the GNU debugger.

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, see <http://www.gnu.org/licenses/>.  */

#include "sim-main.h"
#ifdef HAVE_STRING_H
#include <string.h>
#else
#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include <ctype.h>
#include "libiberty.h"
#include "sim-options.h"
#include "sim-io.h"
#include "sim-assert.h"
#include "version.h"

#include "bfd.h"

/* Add a set of options to the simulator.
   TABLE is an array of OPTIONS terminated by a NULL `opt.name' entry.
   This is intended to be called by modules in their `install' handler.  */

SIM_RC
sim_add_option_table (SIM_DESC sd, sim_cpu *cpu, const OPTION *table)
{
  struct option_list *ol = ((struct option_list *)
			    xmalloc (sizeof (struct option_list)));

  /* Note: The list is constructed in the reverse order we're called so
     later calls will override earlier ones (in case that ever happens).
     This is the intended behaviour.  */

  if (cpu)
    {
      ol->next = CPU_OPTIONS (cpu);
      ol->options = table;
      CPU_OPTIONS (cpu) = ol;
    }
  else
    {
      ol->next = STATE_OPTIONS (sd);
      ol->options = table;
      STATE_OPTIONS (sd) = ol;
    }

  return SIM_RC_OK;
}

/* Standard option table.
   Modules may specify additional ones.
   The caller of sim_parse_args may also specify additional options
   by calling sim_add_option_table first.  */

static DECLARE_OPTION_HANDLER (standard_option_handler);

/* FIXME: We shouldn't print in --help output options that aren't usable.
   Some fine tuning will be necessary.  One can either move less general
   options to another table or use a HAVE_FOO macro to ifdef out unavailable
   options.  */

/* ??? One might want to conditionally compile out the entries that
   aren't enabled.  There's a distinction, however, between options a
   simulator can't support and options that haven't been configured in.
   Certainly options a simulator can't support shouldn't appear in the
   output of --help.  Whether the same thing applies to options that haven't
   been configured in or not isn't something I can get worked up over.
   [Note that conditionally compiling them out might simply involve moving
   the option to another table.]
   If you decide to conditionally compile them out as well, delete this
   comment and add a comment saying that that is the rule.  */

typedef enum {
  OPTION_DEBUG_INSN = OPTION_START,
  OPTION_DEBUG_FILE,
  OPTION_DO_COMMAND,
  OPTION_ARCHITECTURE,
  OPTION_TARGET,
  OPTION_ARCHITECTURE_INFO,
  OPTION_ENVIRONMENT,
  OPTION_ALIGNMENT,
  OPTION_VERBOSE,
  OPTION_ENDIAN,
  OPTION_DEBUG,
  OPTION_HELP,
  OPTION_VERSION,
  OPTION_LOAD_LMA,
  OPTION_LOAD_VMA,
  OPTION_SYSROOT
} STANDARD_OPTIONS;

static const OPTION standard_options[] =
{
  { {"verbose", no_argument, NULL, OPTION_VERBOSE},
      'v', NULL, "Verbose output",
      standard_option_handler, NULL },

  { {"endian", required_argument, NULL, OPTION_ENDIAN},
      'E', "big|little", "Set endianness",
      standard_option_handler, NULL },

  /* This option isn't supported unless all choices are supported in keeping
     with the goal of not printing in --help output things the simulator can't
     do [as opposed to things that just haven't been configured in].  */
  { {"environment", required_argument, NULL, OPTION_ENVIRONMENT},
      '\0', "user|virtual|operating", "Set running environment",
      standard_option_handler },

  { {"alignment", required_argument, NULL, OPTION_ALIGNMENT},
      '\0', "strict|nonstrict|forced", "Set memory access alignment",
      standard_option_handler },

  { {"debug", no_argument, NULL, OPTION_DEBUG},
      'D', NULL, "Print debugging messages",
      standard_option_handler },
  { {"debug-insn", no_argument, NULL, OPTION_DEBUG_INSN},
      '\0', NULL, "Print instruction debugging messages",
      standard_option_handler },
  { {"debug-file", required_argument, NULL, OPTION_DEBUG_FILE},
      '\0', "FILE NAME", "Specify debugging output file",
      standard_option_handler },

  { {"do-command", required_argument, NULL, OPTION_DO_COMMAND},
      '\0', "COMMAND", ""/*undocumented*/,
      standard_option_handler },

  { {"help", no_argument, NULL, OPTION_HELP},
      'H', NULL, "Print help information",
      standard_option_handler },
  { {"version", no_argument, NULL, OPTION_VERSION},
      '\0', NULL, "Print version information",
      standard_option_handler },

  { {"architecture", required_argument, NULL, OPTION_ARCHITECTURE},
      '\0', "MACHINE", "Specify the architecture to use",
      standard_option_handler },
  { {"architecture-info", no_argument, NULL, OPTION_ARCHITECTURE_INFO},
      '\0', NULL, "List supported architectures",
      standard_option_handler },
  { {"info-architecture", no_argument, NULL, OPTION_ARCHITECTURE_INFO},
      '\0', NULL, NULL,
      standard_option_handler },

  { {"target", required_argument, NULL, OPTION_TARGET},
      '\0', "BFDNAME", "Specify the object-code format for the object files",
      standard_option_handler },

  { {"load-lma", no_argument, NULL, OPTION_LOAD_LMA},
      '\0', NULL,
    "Use VMA or LMA addresses when loading image (default LMA)",
      standard_option_handler, "load-{lma,vma}" },
  { {"load-vma", no_argument, NULL, OPTION_LOAD_VMA},
      '\0', NULL, "", standard_option_handler,  "" },

  { {"sysroot", required_argument, NULL, OPTION_SYSROOT},
      '\0', "SYSROOT",
    "Root for system calls with absolute file-names and cwd at start",
      standard_option_handler, NULL },

  { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL, NULL }
};

static SIM_RC
standard_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
			 char *arg, int is_command)
{
  int i,n;

  switch ((STANDARD_OPTIONS) opt)
    {
    case OPTION_VERBOSE:
      STATE_VERBOSE_P (sd) = 1;
      break;

    case OPTION_ENDIAN:
      if (strcmp (arg, "big") == 0)
	{
	  if (WITH_TARGET_BYTE_ORDER == BFD_ENDIAN_LITTLE)
	    {
	      sim_io_eprintf (sd, "Simulator compiled for little endian only.\n");
	      return SIM_RC_FAIL;
	    }
	  /* FIXME:wip: Need to set something in STATE_CONFIG.  */
	  current_target_byte_order = BFD_ENDIAN_BIG;
	}
      else if (strcmp (arg, "little") == 0)
	{
	  if (WITH_TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
	    {
	      sim_io_eprintf (sd, "Simulator compiled for big endian only.\n");
	      return SIM_RC_FAIL;
	    }
	  /* FIXME:wip: Need to set something in STATE_CONFIG.  */
	  current_target_byte_order = BFD_ENDIAN_LITTLE;
	}
      else
	{
	  sim_io_eprintf (sd, "Invalid endian specification `%s'\n", arg);
	  return SIM_RC_FAIL;
	}
      break;

    case OPTION_ENVIRONMENT:
      if (strcmp (arg, "user") == 0)
	STATE_ENVIRONMENT (sd) = USER_ENVIRONMENT;
      else if (strcmp (arg, "virtual") == 0)
	STATE_ENVIRONMENT (sd) = VIRTUAL_ENVIRONMENT;
      else if (strcmp (arg, "operating") == 0)
	STATE_ENVIRONMENT (sd) = OPERATING_ENVIRONMENT;
      else
	{
	  sim_io_eprintf (sd, "Invalid environment specification `%s'\n", arg);
	  return SIM_RC_FAIL;
	}
      if (WITH_ENVIRONMENT != ALL_ENVIRONMENT
	  && WITH_ENVIRONMENT != STATE_ENVIRONMENT (sd))
	{
	  const char *type;
	  switch (WITH_ENVIRONMENT)
	    {
	    case USER_ENVIRONMENT: type = "user"; break;
	    case VIRTUAL_ENVIRONMENT: type = "virtual"; break;
	    case OPERATING_ENVIRONMENT: type = "operating"; break;
	    }
	  sim_io_eprintf (sd, "Simulator compiled for the %s environment only.\n",
			  type);
	  return SIM_RC_FAIL;
	}
      break;

    case OPTION_ALIGNMENT:
      if (strcmp (arg, "strict") == 0)
	{
	  if (WITH_ALIGNMENT == 0 || WITH_ALIGNMENT == STRICT_ALIGNMENT)
	    {
	      current_alignment = STRICT_ALIGNMENT;
	      break;
	    }
	}
      else if (strcmp (arg, "nonstrict") == 0)
	{
	  if (WITH_ALIGNMENT == 0 || WITH_ALIGNMENT == NONSTRICT_ALIGNMENT)
	    {
	      current_alignment = NONSTRICT_ALIGNMENT;
	      break;
	    }
	}
      else if (strcmp (arg, "forced") == 0)
	{
	  if (WITH_ALIGNMENT == 0 || WITH_ALIGNMENT == FORCED_ALIGNMENT)
	    {
	      current_alignment = FORCED_ALIGNMENT;
	      break;
	    }
	}
      else
	{
	  sim_io_eprintf (sd, "Invalid alignment specification `%s'\n", arg);
	  return SIM_RC_FAIL;
	}
      switch (WITH_ALIGNMENT)
	{
	case STRICT_ALIGNMENT:
	  sim_io_eprintf (sd, "Simulator compiled for strict alignment only.\n");
	  break;
	case NONSTRICT_ALIGNMENT:
	  sim_io_eprintf (sd, "Simulator compiled for nonstrict alignment only.\n");
	  break;
	case FORCED_ALIGNMENT:
	  sim_io_eprintf (sd, "Simulator compiled for forced alignment only.\n");
	  break;
	}
      return SIM_RC_FAIL;

    case OPTION_DEBUG:
      if (! WITH_DEBUG)
	sim_io_eprintf (sd, "Debugging not compiled in, `-D' ignored\n");
      else
	{
	  for (n = 0; n < MAX_NR_PROCESSORS; ++n)
	    for (i = 0; i < MAX_DEBUG_VALUES; ++i)
	      CPU_DEBUG_FLAGS (STATE_CPU (sd, n))[i] = 1;
	}
      break;

    case OPTION_DEBUG_INSN :
      if (! WITH_DEBUG)
	sim_io_eprintf (sd, "Debugging not compiled in, `--debug-insn' ignored\n");
      else
	{
	  for (n = 0; n < MAX_NR_PROCESSORS; ++n)
	    CPU_DEBUG_FLAGS (STATE_CPU (sd, n))[DEBUG_INSN_IDX] = 1;
	}
      break;

    case OPTION_DEBUG_FILE :
      if (! WITH_DEBUG)
	sim_io_eprintf (sd, "Debugging not compiled in, `--debug-file' ignored\n");
      else
	{
	  FILE *f = fopen (arg, "w");

	  if (f == NULL)
	    {
	      sim_io_eprintf (sd, "Unable to open debug output file `%s'\n", arg);
	      return SIM_RC_FAIL;
	    }
	  for (n = 0; n < MAX_NR_PROCESSORS; ++n)
	    CPU_DEBUG_FILE (STATE_CPU (sd, n)) = f;
	}
      break;

    case OPTION_DO_COMMAND:
      sim_do_command (sd, arg);
      break;

    case OPTION_ARCHITECTURE:
      {
	const struct bfd_arch_info *ap = bfd_scan_arch (arg);
	if (ap == NULL)
	  {
	    sim_io_eprintf (sd, "Architecture `%s' unknown\n", arg);
	    return SIM_RC_FAIL;
	  }
	STATE_ARCHITECTURE (sd) = ap;
	break;
      }

    case OPTION_ARCHITECTURE_INFO:
      {
	const char **list = bfd_arch_list ();
	const char **lp;
	if (list == NULL)
	  abort ();
	sim_io_printf (sd, "Possible architectures:");
	for (lp = list; *lp != NULL; lp++)
	  sim_io_printf (sd, " %s", *lp);
	sim_io_printf (sd, "\n");
	free (list);
	break;
      }

    case OPTION_TARGET:
      {
	STATE_TARGET (sd) = xstrdup (arg);
	break;
      }

    case OPTION_LOAD_LMA:
      {
	STATE_LOAD_AT_LMA_P (sd) = 1;
	break;
      }

    case OPTION_LOAD_VMA:
      {
	STATE_LOAD_AT_LMA_P (sd) = 0;
	break;
      }

    case OPTION_HELP:
      sim_print_help (sd, is_command);
      if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
	exit (0);
      /* FIXME: 'twould be nice to do something similar if gdb.  */
      break;

    case OPTION_VERSION:
      sim_io_printf (sd, "GNU simulator %s%s\n", PKGVERSION, version);
      if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
	exit (0);
      break;

    case OPTION_SYSROOT:
      /* Don't leak memory in the odd event that there's lots of
	 --sysroot=... options.  We treat "" specially since this
	 is the statically initialized value and cannot free it.  */
      if (simulator_sysroot[0] != '\0')
	free (simulator_sysroot);
      if (arg[0] != '\0')
	simulator_sysroot = xstrdup (arg);
      else
	simulator_sysroot = "";
      break;
    }

  return SIM_RC_OK;
}

/* Add the standard option list to the simulator.  */

SIM_RC
standard_install (SIM_DESC sd)
{
  SIM_ASSERT (STATE_MAGIC (sd) == SIM_MAGIC_NUMBER);
  if (sim_add_option_table (sd, NULL, standard_options) != SIM_RC_OK)
    return SIM_RC_FAIL;
  STATE_LOAD_AT_LMA_P (sd) = 1;
  return SIM_RC_OK;
}

/* Return non-zero if arg is a duplicate argument.
   If ARG is NULL, initialize.  */

#define ARG_HASH_SIZE 97
#define ARG_HASH(a) ((256 * (unsigned char) a[0] + (unsigned char) a[1]) % ARG_HASH_SIZE)

static int
dup_arg_p (const char *arg)
{
  int hash;
  static const char **arg_table = NULL;

  if (arg == NULL)
    {
      if (arg_table == NULL)
	arg_table = (const char **) xmalloc (ARG_HASH_SIZE * sizeof (char *));
      memset (arg_table, 0, ARG_HASH_SIZE * sizeof (char *));
      return 0;
    }

  hash = ARG_HASH (arg);
  while (arg_table[hash] != NULL)
    {
      if (strcmp (arg, arg_table[hash]) == 0)
	return 1;
      /* We assume there won't be more than ARG_HASH_SIZE arguments so we
	 don't check if the table is full.  */
      if (++hash == ARG_HASH_SIZE)
	hash = 0;
    }
  arg_table[hash] = arg;
  return 0;
}

/* Called by sim_open to parse the arguments.  */

SIM_RC
sim_parse_args (SIM_DESC sd, char * const *argv)
{
  int c, i, argc, num_opts, save_opterr;
  char *p, *short_options;
  /* The `val' option struct entry is dynamically assigned for options that
     only come in the long form.  ORIG_VAL is used to get the original value
     back.  */
  int *orig_val;
  struct option *lp, *long_options;
  const struct option_list *ol;
  const OPTION *opt;
  OPTION_HANDLER **handlers;
  sim_cpu **opt_cpu;
  SIM_RC result = SIM_RC_OK;

  /* Count the number of arguments.  */
  argc = countargv (argv);

  /* Count the number of options.  */
  num_opts = 0;
  for (ol = STATE_OPTIONS (sd); ol != NULL; ol = ol->next)
    for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
      ++num_opts;
  for (i = 0; i < MAX_NR_PROCESSORS; ++i)
    for (ol = CPU_OPTIONS (STATE_CPU (sd, i)); ol != NULL; ol = ol->next)
      for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
	++num_opts;

  /* Initialize duplicate argument checker.  */
  (void) dup_arg_p (NULL);

  /* Build the option table for getopt.  */

  long_options = NZALLOC (struct option, num_opts + 1);
  lp = long_options;
  short_options = NZALLOC (char, num_opts * 3 + 1);
  p = short_options;
  handlers = NZALLOC (OPTION_HANDLER *, OPTION_START + num_opts);
  orig_val = NZALLOC (int, OPTION_START + num_opts);
  opt_cpu = NZALLOC (sim_cpu *, OPTION_START + num_opts);

  /* Set '+' as first char so argument permutation isn't done.  This
     is done to stop getopt_long returning options that appear after
     the target program.  Such options should be passed unchanged into
     the program image. */
  *p++ = '+';

  for (i = OPTION_START, ol = STATE_OPTIONS (sd); ol != NULL; ol = ol->next)
    for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
      {
	if (dup_arg_p (opt->opt.name))
	  continue;
	if (opt->shortopt != 0)
	  {
	    *p++ = opt->shortopt;
	    if (opt->opt.has_arg == required_argument)
	      *p++ = ':';
	    else if (opt->opt.has_arg == optional_argument)
	      { *p++ = ':'; *p++ = ':'; }
	    handlers[(unsigned char) opt->shortopt] = opt->handler;
	    if (opt->opt.val != 0)
	      orig_val[(unsigned char) opt->shortopt] = opt->opt.val;
	    else
	      orig_val[(unsigned char) opt->shortopt] = opt->shortopt;
	  }
	if (opt->opt.name != NULL)
	  {
	    *lp = opt->opt;
	    /* Dynamically assign `val' numbers for long options. */
	    lp->val = i++;
	    handlers[lp->val] = opt->handler;
	    orig_val[lp->val] = opt->opt.val;
	    opt_cpu[lp->val] = NULL;
	    ++lp;
	  }
      }

  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
    {
      sim_cpu *cpu = STATE_CPU (sd, c);
      for (ol = CPU_OPTIONS (cpu); ol != NULL; ol = ol->next)
	for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
	  {
#if 0 /* Each option is prepended with --<cpuname>- so this greatly cuts down
	 on the need for dup_arg_p checking.  Maybe in the future it'll be
	 needed so this is just commented out, and not deleted.  */
	    if (dup_arg_p (opt->opt.name))
	      continue;
#endif
	    /* Don't allow short versions of cpu specific options for now.  */
	    if (opt->shortopt != 0)
	      {
		sim_io_eprintf (sd, "internal error, short cpu specific option");
		result = SIM_RC_FAIL;
		break;
	      }
	    if (opt->opt.name != NULL)
	      {
		char *name;
		*lp = opt->opt;
		/* Prepend --<cpuname>- to the option.  */
		if (asprintf (&name, "%s-%s", CPU_NAME (cpu), lp->name) < 0)
		  {
		    sim_io_eprintf (sd, "internal error, out of memory");
		    result = SIM_RC_FAIL;
		    break;
		  }
		lp->name = name;
		/* Dynamically assign `val' numbers for long options. */
		lp->val = i++;
		handlers[lp->val] = opt->handler;
		orig_val[lp->val] = opt->opt.val;
		opt_cpu[lp->val] = cpu;
		++lp;
	      }
	  }
    }

  /* Terminate the short and long option lists.  */
  *p = 0;
  lp->name = NULL;

  /* Ensure getopt is initialized.  */
  optind = 0;

  /* Do not lot getopt throw errors for us.  But don't mess with the state for
     any callers higher up by saving/restoring it.  */
  save_opterr = opterr;
  opterr = 0;

  while (1)
    {
      int longind, optc;

      optc = getopt_long (argc, argv, short_options, long_options, &longind);
      if (optc == -1)
	{
	  if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
	    STATE_PROG_ARGV (sd) = dupargv (argv + optind);
	  break;
	}
      if (optc == '?')
	{
	  /* If getopt rejects a short option, optopt is set to the bad char.
	     If it rejects a long option, we have to look at optind.  In the
	     short option case, argv could be multiple short options.  */
	  const char *badopt;
	  char optbuf[3];

	  if (optopt)
	    {
	      sprintf (optbuf, "-%c", optopt);
	      badopt = optbuf;
	    }
	  else
	    badopt = argv[optind - 1];

	  sim_io_eprintf (sd,
			  "%s: unrecognized option '%s'\n"
			  "Use --help for a complete list of options.\n",
			  STATE_MY_NAME (sd), badopt);

	  result = SIM_RC_FAIL;
	  break;
	}

      if ((*handlers[optc]) (sd, opt_cpu[optc], orig_val[optc], optarg, 0/*!is_command*/) == SIM_RC_FAIL)
	{
	  result = SIM_RC_FAIL;
	  break;
	}
    }

  opterr = save_opterr;

  free (long_options);
  free (short_options);
  free (handlers);
  free (opt_cpu);
  free (orig_val);
  return result;
}

/* Utility of sim_print_help to print a list of option tables.  */

static void
print_help (SIM_DESC sd, sim_cpu *cpu, const struct option_list *ol, int is_command)
{
  const OPTION *opt;

  for ( ; ol != NULL; ol = ol->next)
    for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
      {
	const int indent = 30;
	int comma, len;
	const OPTION *o;

	if (dup_arg_p (opt->opt.name))
	  continue;

	if (opt->doc == NULL)
	  continue;

	if (opt->doc_name != NULL && opt->doc_name [0] == '\0')
	  continue;

	sim_io_printf (sd, "  ");

	comma = 0;
	len = 2;

	/* list any short options (aliases) for the current OPT */
	if (!is_command)
	  {
	    o = opt;
	    do
	      {
		if (o->shortopt != '\0')
		  {
		    sim_io_printf (sd, "%s-%c", comma ? ", " : "", o->shortopt);
		    len += (comma ? 2 : 0) + 2;
		    if (o->arg != NULL)
		      {
			if (o->opt.has_arg == optional_argument)
			  {
			    sim_io_printf (sd, "[%s]", o->arg);
			    len += 1 + strlen (o->arg) + 1;
			  }
			else
			  {
			    sim_io_printf (sd, " %s", o->arg);
			    len += 1 + strlen (o->arg);
			  }
		      }
		    comma = 1;
		  }
		++o;
	      }
	    while (OPTION_VALID_P (o) && o->doc == NULL);
	  }

	/* list any long options (aliases) for the current OPT */
	o = opt;
	do
	  {
	    const char *name;
	    const char *cpu_prefix = cpu ? CPU_NAME (cpu) : NULL;
	    if (o->doc_name != NULL)
	      name = o->doc_name;
	    else
	      name = o->opt.name;
	    if (name != NULL)
	      {
		sim_io_printf (sd, "%s%s%s%s%s",
			       comma ? ", " : "",
			       is_command ? "" : "--",
			       cpu ? cpu_prefix : "",
			       cpu ? "-" : "",
			       name);
		len += ((comma ? 2 : 0)
			+ (is_command ? 0 : 2)
			+ strlen (name));
		if (o->arg != NULL)
		  {
		    if (o->opt.has_arg == optional_argument)
		      {
			sim_io_printf (sd, "[=%s]", o->arg);
			len += 2 + strlen (o->arg) + 1;
		      }
		    else
		      {
			sim_io_printf (sd, " %s", o->arg);
			len += 1 + strlen (o->arg);
		      }
		  }
		comma = 1;
	      }
	    ++o;
	  }
	while (OPTION_VALID_P (o) && o->doc == NULL);

	if (len >= indent)
	  {
	    sim_io_printf (sd, "\n%*s", indent, "");
	  }
	else
	  sim_io_printf (sd, "%*s", indent - len, "");

	/* print the description, word wrap long lines */
	{
	  const char *chp = opt->doc;
	  unsigned doc_width = 80 - indent;
	  while (strlen (chp) >= doc_width) /* some slack */
	    {
	      const char *end = chp + doc_width - 1;
	      while (end > chp && !isspace (*end))
		end --;
	      if (end == chp)
		end = chp + doc_width - 1;
	      /* The cast should be ok - its distances between to
                 points in a string.  */
	      sim_io_printf (sd, "%.*s\n%*s", (int) (end - chp), chp, indent,
			     "");
	      chp = end;
	      while (isspace (*chp) && *chp != '\0')
		chp++;
	    }
	  sim_io_printf (sd, "%s\n", chp);
	}
      }
}

/* Print help messages for the options.  */

void
sim_print_help (SIM_DESC sd, int is_command)
{
  if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
    sim_io_printf (sd, "Usage: %s [options] program [program args]\n",
		   STATE_MY_NAME (sd));

  /* Initialize duplicate argument checker.  */
  (void) dup_arg_p (NULL);

  if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
    sim_io_printf (sd, "Options:\n");
  else
    sim_io_printf (sd, "Commands:\n");

  print_help (sd, NULL, STATE_OPTIONS (sd), is_command);
  sim_io_printf (sd, "\n");

  /* Print cpu-specific options.  */
  {
    int i;

    for (i = 0; i < MAX_NR_PROCESSORS; ++i)
      {
	sim_cpu *cpu = STATE_CPU (sd, i);
	if (CPU_OPTIONS (cpu) == NULL)
	  continue;
	sim_io_printf (sd, "CPU %s specific options:\n", CPU_NAME (cpu));
	print_help (sd, cpu, CPU_OPTIONS (cpu), is_command);
	sim_io_printf (sd, "\n");
      }
  }

  sim_io_printf (sd, "Note: Depending on the simulator configuration some %ss\n",
		 STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE ? "option" : "command");
  sim_io_printf (sd, "      may not be applicable\n");

  if (STATE_OPEN_KIND (sd) == SIM_OPEN_STANDALONE)
    {
      sim_io_printf (sd, "\n");
      sim_io_printf (sd, "program args    Arguments to pass to simulated program.\n");
      sim_io_printf (sd, "                Note: Very few simulators support this.\n");
    }
}

/* Utility of sim_args_command to find the closest match for a command.
   Commands that have "-" in them can be specified as separate words.
   e.g. sim memory-region 0x800000,0x4000
   or   sim memory region 0x800000,0x4000
   If CPU is non-null, use its option table list, otherwise use the main one.
   *PARGI is where to start looking in ARGV.  It is updated to point past
   the found option.  */

static const OPTION *
find_match (SIM_DESC sd, sim_cpu *cpu, char *argv[], int *pargi)
{
  const struct option_list *ol;
  const OPTION *opt;
  /* most recent option match */
  const OPTION *matching_opt = NULL;
  int matching_argi = -1;

  if (cpu)
    ol = CPU_OPTIONS (cpu);
  else
    ol = STATE_OPTIONS (sd);

  /* Skip passed elements specified by *PARGI.  */
  argv += *pargi;

  for ( ; ol != NULL; ol = ol->next)
    for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
      {
	int argi = 0;
	const char *name = opt->opt.name;
	if (name == NULL)
	  continue;
	while (argv [argi] != NULL
	       && strncmp (name, argv [argi], strlen (argv [argi])) == 0)
	  {
	    name = &name [strlen (argv[argi])];
	    if (name [0] == '-')
	      {
		/* leading match ...<a-b-c>-d-e-f - continue search */
		name ++; /* skip `-' */
		argi ++;
		continue;
	      }
	    else if (name [0] == '\0')
	      {
		/* exact match ...<a-b-c-d-e-f> - better than before? */
		if (argi > matching_argi)
		  {
		    matching_argi = argi;
		    matching_opt = opt;
		  }
		break;
	      }
	    else
	      break;
	  }
      }

  *pargi = matching_argi;
  return matching_opt;
}

static char **
complete_option_list (char **ret, size_t *cnt, const struct option_list *ol,
		      const char *text, const char *word)
{
  const OPTION *opt = NULL;
  int argi;
  size_t len = strlen (word);

  for ( ; ol != NULL; ol = ol->next)
    for (opt = ol->options; OPTION_VALID_P (opt); ++opt)
      {
	const char *name = opt->opt.name;

	/* A long option to match against?  */
	if (!name)
	  continue;

	/* Does this option actually match?  */
	if (strncmp (name, word, len))
	  continue;

	ret = xrealloc (ret, ++*cnt * sizeof (ret[0]));
	ret[*cnt - 2] = xstrdup (name);
      }

  return ret;
}

/* All leading text is stored in @text, while the current word being
   completed is stored in @word.  Trailing text of @word is not.  */

char **
sim_complete_command (SIM_DESC sd, const char *text, const char *word)
{
  char **ret = NULL;
  size_t cnt = 1;
  sim_cpu *cpu;

  /* Only complete first word for now.  */
  if (text != word)
    return ret;

  cpu = STATE_CPU (sd, 0);
  if (cpu)
    ret = complete_option_list (ret, &cnt, CPU_OPTIONS (cpu), text, word);
  ret = complete_option_list (ret, &cnt, STATE_OPTIONS (sd), text, word);

  if (ret)
    ret[cnt - 1] = NULL;
  return ret;
}

SIM_RC
sim_args_command (SIM_DESC sd, const char *cmd)
{
  /* something to do? */
  if (cmd == NULL)
    return SIM_RC_OK; /* FIXME - perhaps help would be better */

  if (cmd [0] == '-')
    {
      /* user specified -<opt> ... form? */
      char **argv = buildargv (cmd);
      SIM_RC rc = sim_parse_args (sd, argv);
      freeargv (argv);
      return rc;
    }
  else
    {
      char **argv = buildargv (cmd);
      const OPTION *matching_opt = NULL;
      int matching_argi;
      sim_cpu *cpu;

      if (argv [0] == NULL)
	{
	  freeargv (argv);
	  return SIM_RC_OK; /* FIXME - perhaps help would be better */
	}

      /* First check for a cpu selector.  */
      {
	char *cpu_name = xstrdup (argv[0]);
	char *hyphen = strchr (cpu_name, '-');
	if (hyphen)
	  *hyphen = 0;
	cpu = sim_cpu_lookup (sd, cpu_name);
	if (cpu)
	  {
	    /* If <cpuname>-<command>, point argv[0] at <command>.  */
	    if (hyphen)
	      {
		matching_argi = 0;
		argv[0] += hyphen - cpu_name + 1;
	      }
	    else
	      matching_argi = 1;
	    matching_opt = find_match (sd, cpu, argv, &matching_argi);
	    /* If hyphen found restore argv[0].  */
	    if (hyphen)
	      argv[0] -= hyphen - cpu_name + 1;
	  }
	free (cpu_name);
      }

      /* If that failed, try the main table.  */
      if (matching_opt == NULL)
	{
	  matching_argi = 0;
	  matching_opt = find_match (sd, NULL, argv, &matching_argi);
	}

      if (matching_opt != NULL)
	{
	  switch (matching_opt->opt.has_arg)
	    {
	    case no_argument:
	      if (argv [matching_argi + 1] == NULL)
		matching_opt->handler (sd, cpu, matching_opt->opt.val,
				       NULL, 1/*is_command*/);
	      else
		sim_io_eprintf (sd, "Command `%s' takes no arguments\n",
				matching_opt->opt.name);
	      break;
	    case optional_argument:
	      if (argv [matching_argi + 1] == NULL)
		matching_opt->handler (sd, cpu, matching_opt->opt.val,
				       NULL, 1/*is_command*/);
	      else if (argv [matching_argi + 2] == NULL)
		matching_opt->handler (sd, cpu, matching_opt->opt.val,
				       argv [matching_argi + 1], 1/*is_command*/);
	      else
		sim_io_eprintf (sd, "Command `%s' requires no more than one argument\n",
				matching_opt->opt.name);
	      break;
	    case required_argument:
	      if (argv [matching_argi + 1] == NULL)
		sim_io_eprintf (sd, "Command `%s' requires an argument\n",
				matching_opt->opt.name);
	      else if (argv [matching_argi + 2] == NULL)
		matching_opt->handler (sd, cpu, matching_opt->opt.val,
				       argv [matching_argi + 1], 1/*is_command*/);
	      else
		sim_io_eprintf (sd, "Command `%s' requires only one argument\n",
				matching_opt->opt.name);
	    }
	  freeargv (argv);
	  return SIM_RC_OK;
	}

      freeargv (argv);
    }

  /* didn't find anything that remotly matched */
  return SIM_RC_FAIL;
}