X-Git-Url: http://git.efficios.com/?a=blobdiff_plain;ds=sidebyside;f=gdb%2Fremote-sim.c;h=fd1bc66642389a4879171af8eeee30a5df7cbaec;hb=2d7cc5c7973b6d1bdd9205288863bedadeaf8b41;hp=4eae65aeca33e1cc2b46411ff811085237cb32fb;hpb=7d85a9c0e3639345cb6d19c139ccb9da5095fc76;p=deliverable%2Fbinutils-gdb.git

diff --git a/gdb/remote-sim.c b/gdb/remote-sim.c
index 4eae65aeca..fd1bc66642 100644
--- a/gdb/remote-sim.c
+++ b/gdb/remote-sim.c
@@ -1,7 +1,6 @@
 /* Generic remote debugging interface for simulators.
 
-   Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002,
-   2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+   Copyright (C) 1993-2017 Free Software Foundation, Inc.
 
    Contributed by Cygnus Support.
    Steve Chamberlain (sac@cygnus.com).
@@ -22,14 +21,14 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "gdb_bfd.h"
 #include "inferior.h"
+#include "infrun.h"
 #include "value.h"
-#include "gdb_string.h"
 #include <ctype.h>
 #include <fcntl.h>
 #include <signal.h>
 #include <setjmp.h>
-#include <errno.h>
 #include "terminal.h"
 #include "target.h"
 #include "gdbcore.h"
@@ -37,7 +36,6 @@
 #include "gdb/remote-sim.h"
 #include "command.h"
 #include "regcache.h"
-#include "gdb_assert.h"
 #include "sim-regno.h"
 #include "arch-utils.h"
 #include "readline/readline.h"
@@ -47,8 +45,6 @@
 
 extern void _initialize_remote_sim (void);
 
-static void dump_mem (char *buf, int len);
-
 static void init_callbacks (void);
 
 static void end_callbacks (void);
@@ -63,32 +59,36 @@ static void gdb_os_flush_stderr (host_callback *);
 
 static int gdb_os_poll_quit (host_callback *);
 
-/* printf_filtered is depreciated */
+/* printf_filtered is depreciated.  */
 static void gdb_os_printf_filtered (host_callback *, const char *, ...);
 
 static void gdb_os_vprintf_filtered (host_callback *, const char *, va_list);
 
 static void gdb_os_evprintf_filtered (host_callback *, const char *, va_list);
 
-static void gdb_os_error (host_callback *, const char *, ...) ATTR_NORETURN;
+static void gdb_os_error (host_callback *, const char *, ...)
+     ATTRIBUTE_NORETURN;
 
 static void gdbsim_kill (struct target_ops *);
 
-static void gdbsim_load (char *prog, int fromtty);
+static void gdbsim_load (struct target_ops *self, const char *prog,
+			 int fromtty);
 
-static void gdbsim_open (char *args, int from_tty);
+static void gdbsim_open (const char *args, int from_tty);
 
-static void gdbsim_close (int quitting);
+static void gdbsim_close (struct target_ops *self);
 
-static void gdbsim_detach (struct target_ops *ops, char *args, int from_tty);
+static void gdbsim_detach (struct target_ops *ops, const char *args,
+			   int from_tty);
 
-static void gdbsim_prepare_to_store (struct regcache *regcache);
+static void gdbsim_prepare_to_store (struct target_ops *self,
+				     struct regcache *regcache);
 
 static void gdbsim_files_info (struct target_ops *target);
 
 static void gdbsim_mourn_inferior (struct target_ops *target);
 
-static void gdbsim_stop (ptid_t ptid);
+static void gdbsim_interrupt (struct target_ops *self, ptid_t ptid);
 
 void simulator_command (char *args, int from_tty);
 
@@ -100,47 +100,201 @@ void simulator_command (char *args, int from_tty);
 /* Forward data declarations */
 extern struct target_ops gdbsim_ops;
 
-static int program_loaded = 0;
+static const struct inferior_data *sim_inferior_data_key;
 
-/* We must keep track of whether the simulator has been opened or not because
-   GDB can call a target's close routine twice, but sim_close doesn't allow
-   this.  We also need to record the result of sim_open so we can pass it
-   back to the other sim_foo routines.  */
-static SIM_DESC gdbsim_desc = 0;
+/* Simulator-specific, per-inferior state.  */
+struct sim_inferior_data {
+  /* Flag which indicates whether or not the program has been loaded.  */
+  int program_loaded;
 
-/* This is the ptid we use while we're connected to the simulator.
-   Its value is arbitrary, as the simulator target don't have a notion
-   or processes or threads, but we need something non-null to place in
-   inferior_ptid.  */
-static ptid_t remote_sim_ptid;
+  /* Simulator descriptor for this inferior.  */
+  SIM_DESC gdbsim_desc;
 
-static void
-dump_mem (char *buf, int len)
+  /* This is the ptid we use for this particular simulator instance.  Its
+     value is somewhat arbitrary, as the simulator target don't have a
+     notion of tasks or threads, but we need something non-null to place
+     in inferior_ptid.  For simulators which permit multiple instances,
+     we also need a unique identifier to use for each inferior.  */
+  ptid_t remote_sim_ptid;
+
+  /* Signal with which to resume.  */
+  enum gdb_signal resume_siggnal;
+
+  /* Flag which indicates whether resume should step or not.  */
+  int resume_step;
+};
+
+/* Flag indicating the "open" status of this module.  It's set to 1
+   in gdbsim_open() and 0 in gdbsim_close().  */
+static int gdbsim_is_open = 0;
+
+/* Value of the next pid to allocate for an inferior.  As indicated
+   elsewhere, its initial value is somewhat arbitrary; it's critical
+   though that it's not zero or negative.  */
+static int next_pid;
+#define INITIAL_PID 42000
+
+/* Argument list to pass to sim_open().  It is allocated in gdbsim_open()
+   and deallocated in gdbsim_close().  The lifetime needs to extend beyond
+   the call to gdbsim_open() due to the fact that other sim instances other
+   than the first will be allocated after the gdbsim_open() call.  */
+static char **sim_argv = NULL;
+
+/* OS-level callback functions for write, flush, etc.  */
+static host_callback gdb_callback;
+static int callbacks_initialized = 0;
+
+/* Callback for iterate_over_inferiors.  It checks to see if the sim
+   descriptor passed via ARG is the same as that for the inferior
+   designated by INF.  Return true if so; false otherwise.  */
+
+static int
+check_for_duplicate_sim_descriptor (struct inferior *inf, void *arg)
+{
+  struct sim_inferior_data *sim_data;
+  SIM_DESC new_sim_desc = (SIM_DESC) arg;
+
+  sim_data = ((struct sim_inferior_data *)
+	      inferior_data (inf, sim_inferior_data_key));
+
+  return (sim_data != NULL && sim_data->gdbsim_desc == new_sim_desc);
+}
+
+/* Flags indicating whether or not a sim instance is needed.  One of these
+   flags should be passed to get_sim_inferior_data().  */
+
+enum {SIM_INSTANCE_NOT_NEEDED = 0, SIM_INSTANCE_NEEDED = 1};
+
+/* Obtain pointer to per-inferior simulator data, allocating it if necessary.
+   Attempt to open the sim if SIM_INSTANCE_NEEDED is true.  */
+
+static struct sim_inferior_data *
+get_sim_inferior_data (struct inferior *inf, int sim_instance_needed)
 {
-  if (len <= 8)
+  SIM_DESC sim_desc = NULL;
+  struct sim_inferior_data *sim_data
+    = (struct sim_inferior_data *) inferior_data (inf, sim_inferior_data_key);
+
+  /* Try to allocate a new sim instance, if needed.  We do this ahead of
+     a potential allocation of a sim_inferior_data struct in order to
+     avoid needlessly allocating that struct in the event that the sim
+     instance allocation fails.  */
+  if (sim_instance_needed == SIM_INSTANCE_NEEDED
+      && (sim_data == NULL || sim_data->gdbsim_desc == NULL))
     {
-      if (len == 8 || len == 4)
+      struct inferior *idup;
+      sim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, sim_argv);
+      if (sim_desc == NULL)
+	error (_("Unable to create simulator instance for inferior %d."),
+	       inf->num);
+
+      idup = iterate_over_inferiors (check_for_duplicate_sim_descriptor,
+				     sim_desc);
+      if (idup != NULL)
 	{
-	  long l[2];
-	  memcpy (l, buf, len);
-	  printf_filtered ("\t0x%lx", l[0]);
-	  if (len == 8)
-	    printf_filtered (" 0x%lx", l[1]);
-	  printf_filtered ("\n");
+	  /* We don't close the descriptor due to the fact that it's
+	     shared with some other inferior.  If we were to close it,
+	     that might needlessly muck up the other inferior.  Of
+	     course, it's possible that the damage has already been
+	     done...  Note that it *will* ultimately be closed during
+	     cleanup of the other inferior.  */
+	  sim_desc = NULL;
+	  error (
+ _("Inferior %d and inferior %d would have identical simulator state.\n"
+   "(This simulator does not support the running of more than one inferior.)"),
+		 inf->num, idup->num);
 	}
-      else
+    }
+
+  if (sim_data == NULL)
+    {
+      sim_data = XCNEW(struct sim_inferior_data);
+      set_inferior_data (inf, sim_inferior_data_key, sim_data);
+
+      /* Allocate a ptid for this inferior.  */
+      sim_data->remote_sim_ptid = ptid_build (next_pid, 0, next_pid);
+      next_pid++;
+
+      /* Initialize the other instance variables.  */
+      sim_data->program_loaded = 0;
+      sim_data->gdbsim_desc = sim_desc;
+      sim_data->resume_siggnal = GDB_SIGNAL_0;
+      sim_data->resume_step = 0;
+    }
+  else if (sim_desc)
+    {
+      /* This handles the case where sim_data was allocated prior to
+	 needing a sim instance.  */
+      sim_data->gdbsim_desc = sim_desc;
+    }
+
+
+  return sim_data;
+}
+
+/* Return pointer to per-inferior simulator data using PTID to find the
+   inferior in question.  Return NULL when no inferior is found or
+   when ptid has a zero or negative pid component.  */
+
+static struct sim_inferior_data *
+get_sim_inferior_data_by_ptid (ptid_t ptid, int sim_instance_needed)
+{
+  struct inferior *inf;
+  int pid = ptid_get_pid (ptid);
+
+  if (pid <= 0)
+    return NULL;
+
+  inf = find_inferior_pid (pid);
+
+  if (inf)
+    return get_sim_inferior_data (inf, sim_instance_needed);
+  else
+    return NULL;
+}
+
+/* Free the per-inferior simulator data.  */
+
+static void
+sim_inferior_data_cleanup (struct inferior *inf, void *data)
+{
+  struct sim_inferior_data *sim_data = (struct sim_inferior_data *) data;
+
+  if (sim_data != NULL)
+    {
+      if (sim_data->gdbsim_desc)
 	{
-	  int i;
-	  printf_filtered ("\t");
-	  for (i = 0; i < len; i++)
-	    printf_filtered ("0x%x ", buf[i]);
-	  printf_filtered ("\n");
+	  sim_close (sim_data->gdbsim_desc, 0);
+	  sim_data->gdbsim_desc = NULL;
 	}
+      xfree (sim_data);
     }
 }
 
-static host_callback gdb_callback;
-static int callbacks_initialized = 0;
+static void
+dump_mem (const gdb_byte *buf, int len)
+{
+  fputs_unfiltered ("\t", gdb_stdlog);
+
+  if (len == 8 || len == 4)
+    {
+      uint32_t l[2];
+
+      memcpy (l, buf, len);
+      fprintf_unfiltered (gdb_stdlog, "0x%08x", l[0]);
+      if (len == 8)
+	fprintf_unfiltered (gdb_stdlog, " 0x%08x", l[1]);
+    }
+  else
+    {
+      int i;
+
+      for (i = 0; i < len; i++)
+	fprintf_unfiltered (gdb_stdlog, "0x%02x ", buf[i]);
+    }
+
+  fputs_unfiltered ("\n", gdb_stdlog);
+}
 
 /* Initialize gdb_callback.  */
 
@@ -228,10 +382,9 @@ static void
 gdb_os_printf_filtered (host_callback * p, const char *format,...)
 {
   va_list args;
-  va_start (args, format);
 
+  va_start (args, format);
   vfprintf_filtered (gdb_stdout, format, args);
-
   va_end (args);
 }
 
@@ -257,6 +410,7 @@ static void
 gdb_os_error (host_callback * p, const char *format, ...)
 {
   va_list args;
+
   va_start (args, format);
   verror (format, args);
   va_end (args);
@@ -275,6 +429,10 @@ gdbsim_fetch_register (struct target_ops *ops,
 		       struct regcache *regcache, int regno)
 {
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct inferior *inf = find_inferior_ptid (regcache_get_ptid (regcache));
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (inf, SIM_INSTANCE_NEEDED);
+
   if (regno == -1)
     {
       for (regno = 0; regno < gdbarch_num_regs (gdbarch); regno++)
@@ -289,22 +447,24 @@ gdbsim_fetch_register (struct target_ops *ops,
     case SIM_REGNO_DOES_NOT_EXIST:
       {
 	/* For moment treat a `does not exist' register the same way
-           as an ``unavailable'' register.  */
-	char buf[MAX_REGISTER_SIZE];
+	   as an ``unavailable'' register.  */
+	gdb_byte buf[MAX_REGISTER_SIZE];
 	int nr_bytes;
+
 	memset (buf, 0, MAX_REGISTER_SIZE);
 	regcache_raw_supply (regcache, regno, buf);
 	break;
       }
-      
+
     default:
       {
 	static int warn_user = 1;
-	char buf[MAX_REGISTER_SIZE];
+	gdb_byte buf[MAX_REGISTER_SIZE];
 	int nr_bytes;
+
 	gdb_assert (regno >= 0 && regno < gdbarch_num_regs (gdbarch));
 	memset (buf, 0, MAX_REGISTER_SIZE);
-	nr_bytes = sim_fetch_register (gdbsim_desc,
+	nr_bytes = sim_fetch_register (sim_data->gdbsim_desc,
 				       gdbarch_register_sim_regno
 					 (gdbarch, regno),
 				       buf,
@@ -313,7 +473,8 @@ gdbsim_fetch_register (struct target_ops *ops,
 	    && nr_bytes != register_size (gdbarch, regno) && warn_user)
 	  {
 	    fprintf_unfiltered (gdb_stderr,
-				"Size of register %s (%d/%d) incorrect (%d instead of %d))",
+				"Size of register %s (%d/%d) "
+				"incorrect (%d instead of %d))",
 				gdbarch_register_name (gdbarch, regno),
 				regno,
 				gdbarch_register_sim_regno
@@ -329,7 +490,8 @@ gdbsim_fetch_register (struct target_ops *ops,
 	regcache_raw_supply (regcache, regno, buf);
 	if (remote_debug)
 	  {
-	    printf_filtered ("gdbsim_fetch_register: %d", regno);
+	    fprintf_unfiltered (gdb_stdlog,
+				"gdbsim_fetch_register: %d", regno);
 	    /* FIXME: We could print something more intelligible.  */
 	    dump_mem (buf, register_size (gdbarch, regno));
 	  }
@@ -344,6 +506,10 @@ gdbsim_store_register (struct target_ops *ops,
 		       struct regcache *regcache, int regno)
 {
   struct gdbarch *gdbarch = get_regcache_arch (regcache);
+  struct inferior *inf = find_inferior_ptid (regcache_get_ptid (regcache));
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (inf, SIM_INSTANCE_NEEDED);
+
   if (regno == -1)
     {
       for (regno = 0; regno < gdbarch_num_regs (gdbarch); regno++)
@@ -352,22 +518,27 @@ gdbsim_store_register (struct target_ops *ops,
     }
   else if (gdbarch_register_sim_regno (gdbarch, regno) >= 0)
     {
-      char tmp[MAX_REGISTER_SIZE];
+      gdb_byte tmp[MAX_REGISTER_SIZE];
       int nr_bytes;
+
       regcache_cooked_read (regcache, regno, tmp);
-      nr_bytes = sim_store_register (gdbsim_desc,
+      nr_bytes = sim_store_register (sim_data->gdbsim_desc,
 				     gdbarch_register_sim_regno
 				       (gdbarch, regno),
 				     tmp, register_size (gdbarch, regno));
       if (nr_bytes > 0 && nr_bytes != register_size (gdbarch, regno))
 	internal_error (__FILE__, __LINE__,
 			_("Register size different to expected"));
-      /* FIXME: cagney/2002-05-27: Should check `nr_bytes == 0'
-	 indicating that GDB and the SIM have different ideas about
-	 which registers are fetchable.  */
+      if (nr_bytes < 0)
+	internal_error (__FILE__, __LINE__,
+			_("Register %d not updated"), regno);
+      if (nr_bytes == 0)
+	warning (_("Register %s not updated"),
+		 gdbarch_register_name (gdbarch, regno));
+
       if (remote_debug)
 	{
-	  printf_filtered ("gdbsim_store_register: %d", regno);
+	  fprintf_unfiltered (gdb_stdlog, "gdbsim_store_register: %d", regno);
 	  /* FIXME: We could print something more intelligible.  */
 	  dump_mem (tmp, register_size (gdbarch, regno));
 	}
@@ -381,11 +552,11 @@ static void
 gdbsim_kill (struct target_ops *ops)
 {
   if (remote_debug)
-    printf_filtered ("gdbsim_kill\n");
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_kill\n");
 
   /* There is no need to `kill' running simulator - the simulator is
      not running.  Mourning it is enough.  */
-  target_mourn_inferior ();
+  target_mourn_inferior (inferior_ptid);
 }
 
 /* Load an executable file into the target process.  This is expected to
@@ -393,10 +564,12 @@ gdbsim_kill (struct target_ops *ops)
    GDB's symbol tables to match.  */
 
 static void
-gdbsim_load (char *args, int fromtty)
+gdbsim_load (struct target_ops *self, const char *args, int fromtty)
 {
   char **argv;
-  char *prog;
+  const char *prog;
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NEEDED);
 
   if (args == NULL)
       error_no_arg (_("program to load"));
@@ -410,18 +583,18 @@ gdbsim_load (char *args, int fromtty)
     error (_("GDB sim does not yet support a load offset."));
 
   if (remote_debug)
-    printf_filtered ("gdbsim_load: prog \"%s\"\n", prog);
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_load: prog \"%s\"\n", prog);
 
   /* FIXME: We will print two messages on error.
      Need error to either not print anything if passed NULL or need
      another routine that doesn't take any arguments.  */
-  if (sim_load (gdbsim_desc, prog, NULL, fromtty) == SIM_RC_FAIL)
+  if (sim_load (sim_data->gdbsim_desc, prog, NULL, fromtty) == SIM_RC_FAIL)
     error (_("unable to load program"));
 
   /* FIXME: If a load command should reset the targets registers then
-     a call to sim_create_inferior() should go here. */
+     a call to sim_create_inferior() should go here.  */
 
-  program_loaded = 1;
+  sim_data->program_loaded = 1;
 }
 
 
@@ -434,30 +607,34 @@ gdbsim_load (char *args, int fromtty)
    user types "run" after having attached.  */
 
 static void
-gdbsim_create_inferior (struct target_ops *target, char *exec_file, char *args,
-			char **env, int from_tty)
+gdbsim_create_inferior (struct target_ops *target, const char *exec_file,
+			const std::string &allargs, char **env, int from_tty)
 {
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NEEDED);
   int len;
   char *arg_buf, **argv;
+  const char *args = allargs.c_str ();
 
   if (exec_file == 0 || exec_bfd == 0)
     warning (_("No executable file specified."));
-  if (!program_loaded)
+  if (!sim_data->program_loaded)
     warning (_("No program loaded."));
 
   if (remote_debug)
-    printf_filtered ("gdbsim_create_inferior: exec_file \"%s\", args \"%s\"\n",
-		     (exec_file ? exec_file : "(NULL)"),
-		     args);
+    fprintf_unfiltered (gdb_stdlog,
+			"gdbsim_create_inferior: exec_file \"%s\", args \"%s\"\n",
+			(exec_file ? exec_file : "(NULL)"),
+			args);
 
-  if (ptid_equal (inferior_ptid, remote_sim_ptid))
+  if (ptid_equal (inferior_ptid, sim_data->remote_sim_ptid))
     gdbsim_kill (target);
   remove_breakpoints ();
   init_wait_for_inferior ();
 
   if (exec_file != NULL)
     {
-      len = strlen (exec_file) + 1 + strlen (args) + 1 + /*slop */ 10;
+      len = strlen (exec_file) + 1 + allargs.size () + 1 + /*slop */ 10;
       arg_buf = (char *) alloca (len);
       arg_buf[0] = '\0';
       strcat (arg_buf, exec_file);
@@ -468,51 +645,66 @@ gdbsim_create_inferior (struct target_ops *target, char *exec_file, char *args,
     }
   else
     argv = NULL;
-  sim_create_inferior (gdbsim_desc, exec_bfd, argv, env);
 
-  inferior_ptid = remote_sim_ptid;
-  add_inferior_silent (ptid_get_pid (inferior_ptid));
+  if (!have_inferiors ())
+    init_thread_list ();
+
+  if (sim_create_inferior (sim_data->gdbsim_desc, exec_bfd, argv, env)
+      != SIM_RC_OK)
+    error (_("Unable to create sim inferior."));
+
+  inferior_ptid = sim_data->remote_sim_ptid;
+  inferior_appeared (current_inferior (), ptid_get_pid (inferior_ptid));
   add_thread_silent (inferior_ptid);
 
-  target_mark_running (&gdbsim_ops);
-  insert_breakpoints ();	/* Needed to get correct instruction in cache */
+  insert_breakpoints ();	/* Needed to get correct instruction
+				   in cache.  */
 
-  clear_proceed_status ();
+  clear_proceed_status (0);
 }
 
 /* The open routine takes the rest of the parameters from the command,
    and (if successful) pushes a new target onto the stack.
    Targets should supply this routine, if only to provide an error message.  */
-/* Called when selecting the simulator. EG: (gdb) target sim name.  */
+/* Called when selecting the simulator.  E.g. (gdb) target sim name.  */
 
 static void
-gdbsim_open (char *args, int from_tty)
+gdbsim_open (const char *args, int from_tty)
 {
   int len;
   char *arg_buf;
-  char **argv;
+  struct sim_inferior_data *sim_data;
+  const char *sysroot;
+  SIM_DESC gdbsim_desc;
+
+  sysroot = gdb_sysroot;
+  if (is_target_filename (sysroot))
+    sysroot += strlen (TARGET_SYSROOT_PREFIX);
 
   if (remote_debug)
-    printf_filtered ("gdbsim_open: args \"%s\"\n", args ? args : "(null)");
-
-  /* Remove current simulator if one exists.  Only do this if the simulator
-     has been opened because sim_close requires it.
-     This is important because the call to push_target below will cause
-     sim_close to be called if the simulator is already open, but push_target
-     is called after sim_open!  We can't move the call to push_target before
-     the call to sim_open because sim_open may invoke `error'.  */
-  if (gdbsim_desc != NULL)
+    fprintf_unfiltered (gdb_stdlog,
+			"gdbsim_open: args \"%s\"\n", args ? args : "(null)");
+
+  /* Ensure that the sim target is not on the target stack.  This is
+     necessary, because if it is on the target stack, the call to
+     push_target below will invoke sim_close(), thus freeing various
+     state (including a sim instance) that we allocate prior to
+     invoking push_target().  We want to delay the push_target()
+     operation until after we complete those operations which could
+     error out.  */
+  if (gdbsim_is_open)
     unpush_target (&gdbsim_ops);
 
   len = (7 + 1			/* gdbsim */
 	 + strlen (" -E little")
 	 + strlen (" --architecture=xxxxxxxxxx")
+	 + strlen (" --sysroot=") + strlen (sysroot) +
 	 + (args ? strlen (args) : 0)
 	 + 50) /* slack */ ;
   arg_buf = (char *) alloca (len);
   strcpy (arg_buf, "gdbsim");	/* 7 */
   /* Specify the byte order for the target when it is explicitly
-     specified by the user (not auto detected). */
+     specified by the user (not auto detected).  */
   switch (selected_byte_order ())
     {
     case BFD_ENDIAN_BIG:
@@ -531,20 +723,36 @@ gdbsim_open (char *args, int from_tty)
       strcat (arg_buf, " --architecture=");
       strcat (arg_buf, selected_architecture_name ());
     }
+  /* Pass along gdb's concept of the sysroot.  */
+  strcat (arg_buf, " --sysroot=");
+  strcat (arg_buf, sysroot);
   /* finally, any explicit args */
   if (args)
     {
       strcat (arg_buf, " ");	/* 1 */
       strcat (arg_buf, args);
     }
-  argv = gdb_buildargv (arg_buf);
-  make_cleanup_freeargv (argv);
+  sim_argv = gdb_buildargv (arg_buf);
 
   init_callbacks ();
-  gdbsim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, argv);
+  gdbsim_desc = sim_open (SIM_OPEN_DEBUG, &gdb_callback, exec_bfd, sim_argv);
 
   if (gdbsim_desc == 0)
-    error (_("unable to create simulator instance"));
+    {
+      freeargv (sim_argv);
+      sim_argv = NULL;
+      error (_("unable to create simulator instance"));
+    }
+
+  /* Reset the pid numberings for this batch of sim instances.  */
+  next_pid = INITIAL_PID;
+
+  /* Allocate the inferior data, but do not allocate a sim instance
+     since we've already just done that.  */
+  sim_data = get_sim_inferior_data (current_inferior (),
+				    SIM_INSTANCE_NOT_NEEDED);
+
+  sim_data->gdbsim_desc = gdbsim_desc;
 
   push_target (&gdbsim_ops);
   printf_filtered ("Connected to the simulator.\n");
@@ -552,36 +760,62 @@ gdbsim_open (char *args, int from_tty)
   /* There's nothing running after "target sim" or "load"; not until
      "run".  */
   inferior_ptid = null_ptid;
-  target_mark_exited (&gdbsim_ops);
+
+  gdbsim_is_open = 1;
 }
 
-/* Does whatever cleanup is required for a target that we are no longer
-   going to be calling.  Argument says whether we are quitting gdb and
-   should not get hung in case of errors, or whether we want a clean
-   termination even if it takes a while.  This routine is automatically
-   always called just before a routine is popped off the target stack.
-   Closing file descriptors and freeing memory are typical things it should
-   do.  */
-/* Close out all files and local state before this target loses control. */
+/* Callback for iterate_over_inferiors.  Called (indirectly) by
+   gdbsim_close().  */
+
+static int
+gdbsim_close_inferior (struct inferior *inf, void *arg)
+{
+  struct sim_inferior_data *sim_data
+    = (struct sim_inferior_data *) inferior_data (inf, sim_inferior_data_key);
+  if (sim_data != NULL)
+    {
+      ptid_t ptid = sim_data->remote_sim_ptid;
+
+      sim_inferior_data_cleanup (inf, sim_data);
+      set_inferior_data (inf, sim_inferior_data_key, NULL);
+
+      /* Having a ptid allocated and stored in remote_sim_ptid does
+	 not mean that a corresponding inferior was ever created.
+	 Thus we need to verify the existence of an inferior using the
+	 pid in question before setting inferior_ptid via
+	 switch_to_thread() or mourning the inferior.  */
+      if (find_inferior_ptid (ptid) != NULL)
+	{
+	  switch_to_thread (ptid);
+	  generic_mourn_inferior ();
+	}
+    }
+
+  return 0;
+}
+
+/* Close out all files and local state before this target loses control.  */
 
 static void
-gdbsim_close (int quitting)
+gdbsim_close (struct target_ops *self)
 {
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED);
+
   if (remote_debug)
-    printf_filtered ("gdbsim_close: quitting %d\n", quitting);
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_close\n");
 
-  program_loaded = 0;
+  iterate_over_inferiors (gdbsim_close_inferior, NULL);
 
-  if (gdbsim_desc != NULL)
+  if (sim_argv != NULL)
     {
-      sim_close (gdbsim_desc, quitting);
-      gdbsim_desc = NULL;
+      freeargv (sim_argv);
+      sim_argv = NULL;
     }
 
   end_callbacks ();
-  generic_mourn_inferior ();
-  delete_thread_silent (remote_sim_ptid);
-  delete_inferior_silent (ptid_get_pid (remote_sim_ptid));
+
+  gdbsim_is_open = 0;
 }
 
 /* Takes a program previously attached to and detaches it.
@@ -594,12 +828,12 @@ gdbsim_close (int quitting)
    Use this when you want to detach and do something else with your gdb.  */
 
 static void
-gdbsim_detach (struct target_ops *ops, char *args, int from_tty)
+gdbsim_detach (struct target_ops *ops, const char *args, int from_tty)
 {
   if (remote_debug)
-    printf_filtered ("gdbsim_detach: args \"%s\"\n", args);
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_detach: args \"%s\"\n", args);
 
-  pop_target ();		/* calls gdbsim_close to do the real work */
+  unpush_target (ops);		/* calls gdbsim_close to do the real work */
   if (from_tty)
     printf_filtered ("Ending simulator %s debugging\n", target_shortname);
 }
@@ -608,38 +842,109 @@ gdbsim_detach (struct target_ops *ops, char *args, int from_tty)
    or to run free; SIGGNAL is the signal value (e.g. SIGINT) to be given
    to the target, or zero for no signal.  */
 
-static enum target_signal resume_siggnal;
-static int resume_step;
+struct resume_data
+{
+  enum gdb_signal siggnal;
+  int step;
+};
+
+static int
+gdbsim_resume_inferior (struct inferior *inf, void *arg)
+{
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (inf, SIM_INSTANCE_NOT_NEEDED);
+  struct resume_data *rd = (struct resume_data *) arg;
+
+  if (sim_data)
+    {
+      sim_data->resume_siggnal = rd->siggnal;
+      sim_data->resume_step = rd->step;
+
+      if (remote_debug)
+	fprintf_unfiltered (gdb_stdlog,
+			    _("gdbsim_resume: pid %d, step %d, signal %d\n"),
+			    inf->pid, rd->step, rd->siggnal);
+    }
+
+  /* When called from iterate_over_inferiors, a zero return causes the
+     iteration process to proceed until there are no more inferiors to
+     consider.  */
+  return 0;
+}
 
 static void
 gdbsim_resume (struct target_ops *ops,
-	       ptid_t ptid, int step, enum target_signal siggnal)
+	       ptid_t ptid, int step, enum gdb_signal siggnal)
 {
-  if (!ptid_equal (inferior_ptid, remote_sim_ptid))
+  struct resume_data rd;
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data_by_ptid (ptid, SIM_INSTANCE_NOT_NEEDED);
+
+  rd.siggnal = siggnal;
+  rd.step = step;
+
+  /* We don't access any sim_data members within this function.
+     What's of interest is whether or not the call to
+     get_sim_inferior_data_by_ptid(), above, is able to obtain a
+     non-NULL pointer.  If it managed to obtain a non-NULL pointer, we
+     know we have a single inferior to consider.  If it's NULL, we
+     either have multiple inferiors to resume or an error condition.  */
+
+  if (sim_data)
+    gdbsim_resume_inferior (find_inferior_ptid (ptid), &rd);
+  else if (ptid_equal (ptid, minus_one_ptid))
+    iterate_over_inferiors (gdbsim_resume_inferior, &rd);
+  else
     error (_("The program is not being run."));
-
-  if (remote_debug)
-    printf_filtered ("gdbsim_resume: step %d, signal %d\n", step, siggnal);
-
-  resume_siggnal = siggnal;
-  resume_step = step;
 }
 
-/* Notify the simulator of an asynchronous request to stop.
+/* Notify the simulator of an asynchronous request to interrupt.
 
-   The simulator shall ensure that the stop request is eventually
+   The simulator shall ensure that the interrupt request is eventually
    delivered to the simulator.  If the call is made while the
-   simulator is not running then the stop request is processed when
+   simulator is not running then the interrupt request is processed when
    the simulator is next resumed.
 
-   For simulators that do not support this operation, just abort */
+   For simulators that do not support this operation, just abort.  */
+
+static int
+gdbsim_interrupt_inferior (struct inferior *inf, void *arg)
+{
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (inf, SIM_INSTANCE_NEEDED);
+
+  if (sim_data)
+    {
+      if (!sim_stop (sim_data->gdbsim_desc))
+	{
+	  quit ();
+	}
+    }
+
+  /* When called from iterate_over_inferiors, a zero return causes the
+     iteration process to proceed until there are no more inferiors to
+     consider.  */
+  return 0;
+}
 
 static void
-gdbsim_stop (ptid_t ptid)
+gdbsim_interrupt (struct target_ops *self, ptid_t ptid)
 {
-  if (!sim_stop (gdbsim_desc))
+  struct sim_inferior_data *sim_data;
+
+  if (ptid_equal (ptid, minus_one_ptid))
+    {
+      iterate_over_inferiors (gdbsim_interrupt_inferior, NULL);
+    }
+  else
     {
-      quit ();
+      struct inferior *inf = find_inferior_ptid (ptid);
+
+      if (inf == NULL)
+	error (_("Can't stop pid %d.  No inferior found."),
+	       ptid_get_pid (ptid));
+
+      gdbsim_interrupt_inferior (inf, NULL);
     }
 }
 
@@ -652,38 +957,47 @@ gdb_os_poll_quit (host_callback *p)
   if (deprecated_ui_loop_hook != NULL)
     deprecated_ui_loop_hook (0);
 
-  if (quit_flag)		/* gdb's idea of quit */
-    {
-      quit_flag = 0;		/* we've stolen it */
-      return 1;
-    }
-  else if (immediate_quit)
-    {
-      return 1;
-    }
+  if (check_quit_flag ())	/* gdb's idea of quit */
+    return 1;
   return 0;
 }
 
 /* Wait for inferior process to do something.  Return pid of child,
    or -1 in case of error; store status through argument pointer STATUS,
-   just as `wait' would. */
+   just as `wait' would.  */
 
 static void
 gdbsim_cntrl_c (int signo)
 {
-  gdbsim_stop (remote_sim_ptid);
+  gdbsim_interrupt (NULL, minus_one_ptid);
 }
 
 static ptid_t
 gdbsim_wait (struct target_ops *ops,
-	     ptid_t ptid, struct target_waitstatus *status)
+	     ptid_t ptid, struct target_waitstatus *status, int options)
 {
-  static RETSIGTYPE (*prev_sigint) ();
+  struct sim_inferior_data *sim_data;
+  static sighandler_t prev_sigint;
   int sigrc = 0;
   enum sim_stop reason = sim_running;
 
+  /* This target isn't able to (yet) resume more than one inferior at a time.
+     When ptid is minus_one_ptid, just use the current inferior.  If we're
+     given an explicit pid, we'll try to find it and use that instead.  */
+  if (ptid_equal (ptid, minus_one_ptid))
+    sim_data = get_sim_inferior_data (current_inferior (),
+				      SIM_INSTANCE_NEEDED);
+  else
+    {
+      sim_data = get_sim_inferior_data_by_ptid (ptid, SIM_INSTANCE_NEEDED);
+      if (sim_data == NULL)
+	error (_("Unable to wait for pid %d.  Inferior not found."),
+	       ptid_get_pid (ptid));
+      inferior_ptid = ptid;
+    }
+
   if (remote_debug)
-    printf_filtered ("gdbsim_wait\n");
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_wait\n");
 
 #if defined (HAVE_SIGACTION) && defined (SA_RESTART)
   {
@@ -697,11 +1011,13 @@ gdbsim_wait (struct target_ops *ops,
 #else
   prev_sigint = signal (SIGINT, gdbsim_cntrl_c);
 #endif
-  sim_resume (gdbsim_desc, resume_step, resume_siggnal);
+  sim_resume (sim_data->gdbsim_desc, sim_data->resume_step,
+	      sim_data->resume_siggnal);
+
   signal (SIGINT, prev_sigint);
-  resume_step = 0;
+  sim_data->resume_step = 0;
 
-  sim_stop_reason (gdbsim_desc, &reason, &sigrc);
+  sim_stop_reason (sim_data->gdbsim_desc, &reason, &sigrc);
 
   switch (reason)
     {
@@ -712,24 +1028,24 @@ gdbsim_wait (struct target_ops *ops,
     case sim_stopped:
       switch (sigrc)
 	{
-	case TARGET_SIGNAL_ABRT:
+	case GDB_SIGNAL_ABRT:
 	  quit ();
 	  break;
-	case TARGET_SIGNAL_INT:
-	case TARGET_SIGNAL_TRAP:
+	case GDB_SIGNAL_INT:
+	case GDB_SIGNAL_TRAP:
 	default:
 	  status->kind = TARGET_WAITKIND_STOPPED;
-	  status->value.sig = sigrc;
+	  status->value.sig = (enum gdb_signal) sigrc;
 	  break;
 	}
       break;
     case sim_signalled:
       status->kind = TARGET_WAITKIND_SIGNALLED;
-      status->value.sig = sigrc;
+      status->value.sig = (enum gdb_signal) sigrc;
       break;
     case sim_running:
     case sim_polling:
-      /* FIXME: Is this correct? */
+      /* FIXME: Is this correct?  */
       break;
     }
 
@@ -743,71 +1059,109 @@ gdbsim_wait (struct target_ops *ops,
    debugged.  */
 
 static void
-gdbsim_prepare_to_store (struct regcache *regcache)
+gdbsim_prepare_to_store (struct target_ops *self, struct regcache *regcache)
 {
-  /* Do nothing, since we can store individual regs */
+  /* Do nothing, since we can store individual regs.  */
 }
 
-/* Transfer LEN bytes between GDB address MYADDR and target address
-   MEMADDR.  If WRITE is non-zero, transfer them to the target,
-   otherwise transfer them from the target.  TARGET is unused.
+/* Helper for gdbsim_xfer_partial that handles memory transfers.
+   Arguments are like target_xfer_partial.  */
 
-   Returns the number of bytes transferred. */
+static enum target_xfer_status
+gdbsim_xfer_memory (struct target_ops *target,
+		    gdb_byte *readbuf, const gdb_byte *writebuf,
+		    ULONGEST memaddr, ULONGEST len, ULONGEST *xfered_len)
+{
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED);
+  int l;
 
-static int
-gdbsim_xfer_inferior_memory (CORE_ADDR memaddr, gdb_byte *myaddr, int len,
-			     int write, struct mem_attrib *attrib,
-			     struct target_ops *target)
-{
-  /* If no program is running yet, then ignore the simulator for
-     memory.  Pass the request down to the next target, hopefully
-     an exec file.  */
-  if (!target_has_execution)
-    return 0;
+  /* If this target doesn't have memory yet, return 0 causing the
+     request to be passed to a lower target, hopefully an exec
+     file.  */
+  if (!target->to_has_memory (target))
+    return TARGET_XFER_EOF;
 
-  if (!program_loaded)
+  if (!sim_data->program_loaded)
     error (_("No program loaded."));
 
+  /* Note that we obtained the sim_data pointer above using
+     SIM_INSTANCE_NOT_NEEDED.  We do this so that we don't needlessly
+     allocate a sim instance prior to loading a program.   If we
+     get to this point in the code though, gdbsim_desc should be
+     non-NULL.  (Note that a sim instance is needed in order to load
+     the program...)  */
+  gdb_assert (sim_data->gdbsim_desc != NULL);
+
   if (remote_debug)
+    fprintf_unfiltered (gdb_stdlog,
+			"gdbsim_xfer_memory: readbuf %s, writebuf %s, "
+			"memaddr %s, len %s\n",
+			host_address_to_string (readbuf),
+			host_address_to_string (writebuf),
+			paddress (target_gdbarch (), memaddr),
+			pulongest (len));
+
+  if (writebuf)
     {
-      /* FIXME: Send to something other than STDOUT? */
-      printf_filtered ("gdbsim_xfer_inferior_memory: myaddr 0x");
-      gdb_print_host_address (myaddr, gdb_stdout);
-      printf_filtered (", memaddr 0x%s, len %d, write %d\n",
-		       paddr_nz (memaddr), len, write);
-      if (remote_debug && write)
-	dump_mem (myaddr, len);
+      if (remote_debug && len > 0)
+	dump_mem (writebuf, len);
+      l = sim_write (sim_data->gdbsim_desc, memaddr, writebuf, len);
     }
-
-  if (write)
+  else
     {
-      len = sim_write (gdbsim_desc, memaddr, myaddr, len);
+      l = sim_read (sim_data->gdbsim_desc, memaddr, readbuf, len);
+      if (remote_debug && len > 0)
+	dump_mem (readbuf, len);
+    }
+  if (l > 0)
+    {
+      *xfered_len = (ULONGEST) l;
+      return TARGET_XFER_OK;
     }
+  else if (l == 0)
+    return TARGET_XFER_EOF;
   else
+    return TARGET_XFER_E_IO;
+}
+
+/* Target to_xfer_partial implementation.  */
+
+static enum target_xfer_status
+gdbsim_xfer_partial (struct target_ops *ops, enum target_object object,
+		     const char *annex, gdb_byte *readbuf,
+		     const gdb_byte *writebuf, ULONGEST offset, ULONGEST len,
+		     ULONGEST *xfered_len)
+{
+  switch (object)
     {
-      len = sim_read (gdbsim_desc, memaddr, myaddr, len);
-      if (remote_debug && len > 0)
-	dump_mem (myaddr, len);
+    case TARGET_OBJECT_MEMORY:
+      return gdbsim_xfer_memory (ops, readbuf, writebuf, offset, len,
+				 xfered_len);
+
+    default:
+      return TARGET_XFER_E_IO;
     }
-  return len;
 }
 
 static void
 gdbsim_files_info (struct target_ops *target)
 {
-  char *file = "nothing";
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NEEDED);
+  const char *file = "nothing";
 
   if (exec_bfd)
     file = bfd_get_filename (exec_bfd);
 
   if (remote_debug)
-    printf_filtered ("gdbsim_files_info: file \"%s\"\n", file);
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_files_info: file \"%s\"\n", file);
 
   if (exec_bfd)
     {
-      printf_filtered ("\tAttached to %s running program %s\n",
-		       target_shortname, file);
-      sim_info (gdbsim_desc, 0);
+      fprintf_unfiltered (gdb_stdlog, "\tAttached to %s running program %s\n",
+			  target_shortname, file);
+      sim_info (sim_data->gdbsim_desc, 0);
     }
 }
 
@@ -816,13 +1170,15 @@ gdbsim_files_info (struct target_ops *target)
 static void
 gdbsim_mourn_inferior (struct target_ops *target)
 {
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED);
+
   if (remote_debug)
-    printf_filtered ("gdbsim_mourn_inferior:\n");
+    fprintf_unfiltered (gdb_stdlog, "gdbsim_mourn_inferior:\n");
 
   remove_breakpoints ();
-  target_mark_exited (target);
   generic_mourn_inferior ();
-  delete_thread_silent (remote_sim_ptid);
+  delete_thread_silent (sim_data->remote_sim_ptid);
 }
 
 /* Pass the command argument through to the simulator verbatim.  The
@@ -831,35 +1187,81 @@ gdbsim_mourn_inferior (struct target_ops *target)
 void
 simulator_command (char *args, int from_tty)
 {
-  if (gdbsim_desc == NULL)
+  struct sim_inferior_data *sim_data;
+
+  /* We use inferior_data() instead of get_sim_inferior_data() here in
+     order to avoid attaching a sim_inferior_data struct to an
+     inferior unnecessarily.  The reason we take such care here is due
+     to the fact that this function, simulator_command(), may be called
+     even when the sim target is not active.  If we were to use
+     get_sim_inferior_data() here, it is possible that this call would
+     be made either prior to gdbsim_open() or after gdbsim_close(),
+     thus allocating memory that would not be garbage collected until
+     the ultimate destruction of the associated inferior.  */
+
+  sim_data  = ((struct sim_inferior_data *)
+	       inferior_data (current_inferior (), sim_inferior_data_key));
+  if (sim_data == NULL || sim_data->gdbsim_desc == NULL)
     {
 
       /* PREVIOUSLY: The user may give a command before the simulator
-         is opened. [...] (??? assuming of course one wishes to
-         continue to allow commands to be sent to unopened simulators,
-         which isn't entirely unreasonable). */
+	 is opened. [...] (??? assuming of course one wishes to
+	 continue to allow commands to be sent to unopened simulators,
+	 which isn't entirely unreasonable).  */
 
       /* The simulator is a builtin abstraction of a remote target.
-         Consistent with that model, access to the simulator, via sim
-         commands, is restricted to the period when the channel to the
-         simulator is open. */
+	 Consistent with that model, access to the simulator, via sim
+	 commands, is restricted to the period when the channel to the
+	 simulator is open.  */
 
       error (_("Not connected to the simulator target"));
     }
 
-  sim_do_command (gdbsim_desc, args);
+  sim_do_command (sim_data->gdbsim_desc, args);
 
   /* Invalidate the register cache, in case the simulator command does
-     something funny. */
+     something funny.  */
   registers_changed ();
 }
 
+static VEC (char_ptr) *
+sim_command_completer (struct cmd_list_element *ignore, const char *text,
+		       const char *word)
+{
+  struct sim_inferior_data *sim_data;
+  char **tmp;
+  int i;
+  VEC (char_ptr) *result = NULL;
+
+  sim_data = ((struct sim_inferior_data *)
+	      inferior_data (current_inferior (), sim_inferior_data_key));
+  if (sim_data == NULL || sim_data->gdbsim_desc == NULL)
+    return NULL;
+
+  tmp = sim_complete_command (sim_data->gdbsim_desc, text, word);
+  if (tmp == NULL)
+    return NULL;
+
+  /* Transform the array into a VEC, and then free the array.  */
+  for (i = 0; tmp[i] != NULL; i++)
+    VEC_safe_push (char_ptr, result, tmp[i]);
+  xfree (tmp);
+
+  return result;
+}
+
 /* Check to see if a thread is still alive.  */
 
 static int
 gdbsim_thread_alive (struct target_ops *ops, ptid_t ptid)
 {
-  if (ptid_equal (ptid, remote_sim_ptid))
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data_by_ptid (ptid, SIM_INSTANCE_NOT_NEEDED);
+
+  if (sim_data == NULL)
+    return 0;
+
+  if (ptid_equal (ptid, sim_data->remote_sim_ptid))
     /* The simulators' task is always alive.  */
     return 1;
 
@@ -869,21 +1271,39 @@ gdbsim_thread_alive (struct target_ops *ops, ptid_t ptid)
 /* Convert a thread ID to a string.  Returns the string in a static
    buffer.  */
 
-static char *
+static const char *
 gdbsim_pid_to_str (struct target_ops *ops, ptid_t ptid)
 {
-  static char buf[64];
+  return normal_pid_to_str (ptid);
+}
 
-  if (ptid_equal (remote_sim_ptid, ptid))
-    {
-      xsnprintf (buf, sizeof buf, "Thread <main>");
-      return buf;
-    }
+/* Simulator memory may be accessed after the program has been loaded.  */
 
-  return normal_pid_to_str (ptid);
+static int
+gdbsim_has_all_memory (struct target_ops *ops)
+{
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED);
+
+  if (!sim_data->program_loaded)
+    return 0;
+
+  return 1;
 }
 
-/* Define the target subroutine names */
+static int
+gdbsim_has_memory (struct target_ops *ops)
+{
+  struct sim_inferior_data *sim_data
+    = get_sim_inferior_data (current_inferior (), SIM_INSTANCE_NOT_NEEDED);
+
+  if (!sim_data->program_loaded)
+    return 0;
+
+  return 1;
+}
+
+/* Define the target subroutine names.  */
 
 struct target_ops gdbsim_ops;
 
@@ -901,7 +1321,7 @@ init_gdbsim_ops (void)
   gdbsim_ops.to_fetch_registers = gdbsim_fetch_register;
   gdbsim_ops.to_store_registers = gdbsim_store_register;
   gdbsim_ops.to_prepare_to_store = gdbsim_prepare_to_store;
-  gdbsim_ops.deprecated_xfer_memory = gdbsim_xfer_inferior_memory;
+  gdbsim_ops.to_xfer_partial = gdbsim_xfer_partial;
   gdbsim_ops.to_files_info = gdbsim_files_info;
   gdbsim_ops.to_insert_breakpoint = memory_insert_breakpoint;
   gdbsim_ops.to_remove_breakpoint = memory_remove_breakpoint;
@@ -909,28 +1329,30 @@ init_gdbsim_ops (void)
   gdbsim_ops.to_load = gdbsim_load;
   gdbsim_ops.to_create_inferior = gdbsim_create_inferior;
   gdbsim_ops.to_mourn_inferior = gdbsim_mourn_inferior;
-  gdbsim_ops.to_stop = gdbsim_stop;
+  gdbsim_ops.to_interrupt = gdbsim_interrupt;
   gdbsim_ops.to_thread_alive = gdbsim_thread_alive;
   gdbsim_ops.to_pid_to_str = gdbsim_pid_to_str;
   gdbsim_ops.to_stratum = process_stratum;
-  gdbsim_ops.to_has_all_memory = 1;
-  gdbsim_ops.to_has_memory = 1;
-  gdbsim_ops.to_has_stack = 1;
-  gdbsim_ops.to_has_registers = 1;
-  gdbsim_ops.to_has_execution = 1;
+  gdbsim_ops.to_has_all_memory = gdbsim_has_all_memory;
+  gdbsim_ops.to_has_memory = gdbsim_has_memory;
+  gdbsim_ops.to_has_stack = default_child_has_stack;
+  gdbsim_ops.to_has_registers = default_child_has_registers;
+  gdbsim_ops.to_has_execution = default_child_has_execution;
   gdbsim_ops.to_magic = OPS_MAGIC;
 }
 
 void
 _initialize_remote_sim (void)
 {
+  struct cmd_list_element *c;
+
   init_gdbsim_ops ();
   add_target (&gdbsim_ops);
 
-  add_com ("sim", class_obscure, simulator_command,
-	   _("Send a command to the simulator."));
+  c = add_com ("sim", class_obscure, simulator_command,
+	       _("Send a command to the simulator."));
+  set_cmd_completer (c, sim_command_completer);
 
-  /* Yes, 42000 is arbitrary.  The only sense out of it, is that it
-     isn't 0.  */
-  remote_sim_ptid = ptid_build (42000, 0, 42000);
+  sim_inferior_data_key
+    = register_inferior_data_with_cleanup (NULL, sim_inferior_data_cleanup);
 }