gdb/

* arch-utils.c (target_byte_order_user): Renamed from
	target_byte_order.
	(target_byte_order_auto, selected_byte_order): Removed.
	(show_endian): Check target_byte_order_user.
	(set_endian): Always update the architecture.  Set
	target_byte_order_user after success.
	(target_architecture_auto): Removed.
	(target_architecture_user): New.
	(selected_architecture_name, show_architecture): Check it.
	(set_architecture): Set target_architecture_user after success.
	(gdbarch_from_bfd): Check the argument.
	(default_byte_order): New.
	(initialize_current_architecture): Set the global default
	architecture and endianness.
	(gdbarch_info_fill): Remove GDBARCH argument.  Do not check the
	previous architecture.  Use exec_bfd, global selected architecture
	and endianness, and global defaults.
	* arch-utils.h (selected_byte_order): Remove prototype.
	(gdbarch_info_fill): Update.
	* exec.c (exec_file_attach): Update the architecture after removing
	the current file.
	* gdbarch.sh: Update comments.
	(find_arch_by_info): Remove OLD_GDBARCH argument.  Update call to
	gdbarch_info_fill.
	(gdbarch_find_by_info): Update call to find_arch_by_info.
	* gdbarch.h, gdbarch.c: Regenerated.
	* remote-sim.c (gdbsim_open): Use TARGET_BYTE_ORDER.
gdb/doc/
	* gdbint.texinfo (Target Architecture Definition): Add new
	Initializing a New Architecture section.

gdb/ChangeLog

@@ -1,3 +1,33 @@
+2006-11-10  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* arch-utils.c (target_byte_order_user): Renamed from
+	target_byte_order.
+	(target_byte_order_auto, selected_byte_order): Removed.
+	(show_endian): Check target_byte_order_user.
+	(set_endian): Always update the architecture.  Set
+	target_byte_order_user after success.
+	(target_architecture_auto): Removed.
+	(target_architecture_user): New.
+	(selected_architecture_name, show_architecture): Check it.
+	(set_architecture): Set target_architecture_user after success.
+	(gdbarch_from_bfd): Check the argument.
+	(default_byte_order): New.
+	(initialize_current_architecture): Set the global default
+	architecture and endianness.
+	(gdbarch_info_fill): Remove GDBARCH argument.  Do not check the
+	previous architecture.  Use exec_bfd, global selected architecture
+	and endianness, and global defaults.
+	* arch-utils.h (selected_byte_order): Remove prototype.
+	(gdbarch_info_fill): Update.
+	* exec.c (exec_file_attach): Update the architecture after removing
+	the current file.
+	* gdbarch.sh: Update comments.
+	(find_arch_by_info): Remove OLD_GDBARCH argument.  Update call to
+	gdbarch_info_fill.
+	(gdbarch_find_by_info): Update call to find_arch_by_info.
+	* gdbarch.h, gdbarch.c: Regenerated.
+	* remote-sim.c (gdbsim_open): Use TARGET_BYTE_ORDER.
+
 2006-11-09  Joel Brobecker  <brobecker@adacore.com>
 
 	* sparc-tdep.c (sparc_fetch_instruction): Read instruction

gdb/arch-utils.c

@@ -335,24 +335,7 @@ generic_instruction_nullified (struct gdbarch *gdbarch,
 
 /* Functions to manipulate the endianness of the target.  */
 
-/* ``target_byte_order'' is only used when non- multi-arch.
-   Multi-arch targets obtain the current byte order using the
-   TARGET_BYTE_ORDER gdbarch method.
-
-   The choice of initial value is entirely arbitrary.  During startup,
-   the function initialize_current_architecture() updates this value
-   based on default byte-order information extracted from BFD.  */
-static int target_byte_order = BFD_ENDIAN_BIG;
-static int target_byte_order_auto = 1;
-
-enum bfd_endian
-selected_byte_order (void)
-{
-  if (target_byte_order_auto)
-    return BFD_ENDIAN_UNKNOWN;
-  else
-    return target_byte_order;
-}
+static int target_byte_order_user = BFD_ENDIAN_UNKNOWN;
 
 static const char endian_big[] = "big";
 static const char endian_little[] = "little";
@@ -372,7 +355,7 @@ static void
 show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 	     const char *value)
 {
-  if (target_byte_order_auto)
+  if (target_byte_order_user != BFD_ENDIAN_UNKNOWN)
     if (TARGET_BYTE_ORDER == BFD_ENDIAN_BIG)
       fprintf_unfiltered (file, _("The target endianness is set automatically "
 				  "(currently big endian)\n"));
@@ -391,31 +374,37 @@ show_endian (struct ui_file *file, int from_tty, struct cmd_list_element *c,
 static void
 set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 {
+  struct gdbarch_info info;
+
+  gdbarch_info_init (&info);
+
   if (set_endian_string == endian_auto)
     {
-      target_byte_order_auto = 1;
+      target_byte_order_user = BFD_ENDIAN_UNKNOWN;
+      if (! gdbarch_update_p (info))
+	internal_error (__FILE__, __LINE__,
+			_("set_endian: architecture update failed"));
     }
   else if (set_endian_string == endian_little)
     {
-      struct gdbarch_info info;
-      target_byte_order_auto = 0;
-      gdbarch_info_init (&info);
       info.byte_order = BFD_ENDIAN_LITTLE;
       if (! gdbarch_update_p (info))
 	printf_unfiltered (_("Little endian target not supported by GDB\n"));
+      else
+	target_byte_order_user = BFD_ENDIAN_LITTLE;
     }
   else if (set_endian_string == endian_big)
     {
-      struct gdbarch_info info;
-      target_byte_order_auto = 0;
-      gdbarch_info_init (&info);
       info.byte_order = BFD_ENDIAN_BIG;
       if (! gdbarch_update_p (info))
 	printf_unfiltered (_("Big endian target not supported by GDB\n"));
+      else
+	target_byte_order_user = BFD_ENDIAN_BIG;
     }
   else
     internal_error (__FILE__, __LINE__,
 		    _("set_endian: bad value"));
+
   show_endian (gdb_stdout, from_tty, NULL, NULL);
 }
 
@@ -423,14 +412,14 @@ set_endian (char *ignore_args, int from_tty, struct cmd_list_element *c)
 
 enum set_arch { set_arch_auto, set_arch_manual };
 
-static int target_architecture_auto = 1;
+static const struct bfd_arch_info *target_architecture_user;
 
 static const char *set_architecture_string;
 
 const char *
 selected_architecture_name (void)
 {
-  if (target_architecture_auto)
+  if (target_architecture_user == NULL)
     return NULL;
   else
     return set_architecture_string;
@@ -445,7 +434,7 @@ show_architecture (struct ui_file *file, int from_tty,
 {
   const char *arch;
   arch = TARGET_ARCHITECTURE->printable_name;
-  if (target_architecture_auto)
+  if (target_architecture_user == NULL)
     fprintf_filtered (file, _("\
 The target architecture is set automatically (currently %s)\n"), arch);
   else
@@ -460,20 +449,25 @@ The target architecture is assumed to be %s\n"), arch);
 static void
 set_architecture (char *ignore_args, int from_tty, struct cmd_list_element *c)
 {
+  struct gdbarch_info info;
+
+  gdbarch_info_init (&info);
+
   if (strcmp (set_architecture_string, "auto") == 0)
     {
-      target_architecture_auto = 1;
+      target_architecture_user = NULL;
+      if (!gdbarch_update_p (info))
+	internal_error (__FILE__, __LINE__,
+			_("could not select an architecture automatically"));
     }
   else
     {
-      struct gdbarch_info info;
-      gdbarch_info_init (&info);
       info.bfd_arch_info = bfd_scan_arch (set_architecture_string);
       if (info.bfd_arch_info == NULL)
 	internal_error (__FILE__, __LINE__,
 			_("set_architecture: bfd_scan_arch failed"));
       if (gdbarch_update_p (info))
-	target_architecture_auto = 0;
+	target_architecture_user = info.bfd_arch_info;
       else
 	printf_unfiltered (_("Architecture `%s' not recognized.\n"),
 			   set_architecture_string);
@@ -530,6 +524,13 @@ gdbarch_from_bfd (bfd *abfd)
   struct gdbarch *new_gdbarch;
   struct gdbarch_info info;
 
+  /* If we call gdbarch_find_by_info without filling in info.abfd,
+     then it will use the global exec_bfd.  That's fine if we don't
+     have one of those either.  And that's the only time we should
+     reach here with a NULL ABFD argument - when we are discarding
+     the executable.  */
+  gdb_assert (abfd != NULL || exec_bfd == NULL);
+
   gdbarch_info_init (&info);
   info.abfd = abfd;
   return gdbarch_find_by_info (info);
@@ -567,6 +568,8 @@ static const bfd_target *default_bfd_vec = &DEFAULT_BFD_VEC;
 static const bfd_target *default_bfd_vec;
 #endif
 
+static int default_byte_order = BFD_ENDIAN_UNKNOWN;
+
 void
 initialize_current_architecture (void)
 {
@@ -577,10 +580,7 @@ initialize_current_architecture (void)
   gdbarch_info_init (&info);
   
   /* Find a default architecture. */
-  if (info.bfd_arch_info == NULL
-      && default_bfd_arch != NULL)
-    info.bfd_arch_info = default_bfd_arch;
-  if (info.bfd_arch_info == NULL)
+  if (default_bfd_arch == NULL)
     {
       /* Choose the architecture by taking the first one
 	 alphabetically. */
@@ -594,30 +594,32 @@ initialize_current_architecture (void)
       if (chosen == NULL)
 	internal_error (__FILE__, __LINE__,
 			_("initialize_current_architecture: No arch"));
-      info.bfd_arch_info = bfd_scan_arch (chosen);
-      if (info.bfd_arch_info == NULL)
+      default_bfd_arch = bfd_scan_arch (chosen);
+      if (default_bfd_arch == NULL)
 	internal_error (__FILE__, __LINE__,
 			_("initialize_current_architecture: Arch not found"));
     }
 
+  info.bfd_arch_info = default_bfd_arch;
+
   /* Take several guesses at a byte order.  */
-  if (info.byte_order == BFD_ENDIAN_UNKNOWN
+  if (default_byte_order == BFD_ENDIAN_UNKNOWN
       && default_bfd_vec != NULL)
     {
       /* Extract BFD's default vector's byte order. */
       switch (default_bfd_vec->byteorder)
 	{
 	case BFD_ENDIAN_BIG:
-	  info.byte_order = BFD_ENDIAN_BIG;
+	  default_byte_order = BFD_ENDIAN_BIG;
 	  break;
 	case BFD_ENDIAN_LITTLE:
-	  info.byte_order = BFD_ENDIAN_LITTLE;
+	  default_byte_order = BFD_ENDIAN_LITTLE;
 	  break;
 	default:
 	  break;
 	}
     }
-  if (info.byte_order == BFD_ENDIAN_UNKNOWN)
+  if (default_byte_order == BFD_ENDIAN_UNKNOWN)
     {
       /* look for ``*el-*'' in the target name. */
       const char *chp;
@@ -625,14 +627,16 @@ initialize_current_architecture (void)
       if (chp != NULL
 	  && chp - 2 >= target_name
 	  && strncmp (chp - 2, "el", 2) == 0)
-	info.byte_order = BFD_ENDIAN_LITTLE;
+	default_byte_order = BFD_ENDIAN_LITTLE;
     }
-  if (info.byte_order == BFD_ENDIAN_UNKNOWN)
+  if (default_byte_order == BFD_ENDIAN_UNKNOWN)
     {
       /* Wire it to big-endian!!! */
-      info.byte_order = BFD_ENDIAN_BIG;
+      default_byte_order = BFD_ENDIAN_BIG;
     }
 
+  info.byte_order = default_byte_order;
+
   if (! gdbarch_update_p (info))
     internal_error (__FILE__, __LINE__,
 		    _("initialize_current_architecture: Selection of "
@@ -674,48 +678,46 @@ gdbarch_info_init (struct gdbarch_info *info)
 }
 
 /* Similar to init, but this time fill in the blanks.  Information is
-   obtained from the specified architecture, global "set ..." options,
-   and explicitly initialized INFO fields.  */
+   obtained from the global "set ..." options and explicitly
+   initialized INFO fields.  */
 
 void
-gdbarch_info_fill (struct gdbarch *gdbarch, struct gdbarch_info *info)
+gdbarch_info_fill (struct gdbarch_info *info)
 {
+  /* Check for the current file.  */
+  if (info->abfd == NULL)
+    info->abfd = exec_bfd;
+
   /* "(gdb) set architecture ...".  */
   if (info->bfd_arch_info == NULL
-      && !target_architecture_auto
-      && gdbarch != NULL)
-    info->bfd_arch_info = gdbarch_bfd_arch_info (gdbarch);
+      && target_architecture_user)
+    info->bfd_arch_info = target_architecture_user;
   if (info->bfd_arch_info == NULL
       && info->abfd != NULL
       && bfd_get_arch (info->abfd) != bfd_arch_unknown
       && bfd_get_arch (info->abfd) != bfd_arch_obscure)
     info->bfd_arch_info = bfd_get_arch_info (info->abfd);
-  if (info->bfd_arch_info == NULL
-      && gdbarch != NULL)
-    info->bfd_arch_info = gdbarch_bfd_arch_info (gdbarch);
+  /* From the default.  */
+  if (info->bfd_arch_info == NULL)
+    info->bfd_arch_info = default_bfd_arch;
 
   /* "(gdb) set byte-order ...".  */
   if (info->byte_order == BFD_ENDIAN_UNKNOWN
-      && !target_byte_order_auto
-      && gdbarch != NULL)
-    info->byte_order = gdbarch_byte_order (gdbarch);
+      && target_byte_order_user != BFD_ENDIAN_UNKNOWN)
+    info->byte_order = target_byte_order_user;
   /* From the INFO struct.  */
   if (info->byte_order == BFD_ENDIAN_UNKNOWN
       && info->abfd != NULL)
     info->byte_order = (bfd_big_endian (info->abfd) ? BFD_ENDIAN_BIG
-		       : bfd_little_endian (info->abfd) ? BFD_ENDIAN_LITTLE
-		       : BFD_ENDIAN_UNKNOWN);
-  /* From the current target.  */
-  if (info->byte_order == BFD_ENDIAN_UNKNOWN
-      && gdbarch != NULL)
-    info->byte_order = gdbarch_byte_order (gdbarch);
+			: bfd_little_endian (info->abfd) ? BFD_ENDIAN_LITTLE
+			: BFD_ENDIAN_UNKNOWN);
+  /* From the default.  */
+  if (info->byte_order == BFD_ENDIAN_UNKNOWN)
+    info->byte_order = default_byte_order;
 
   /* "(gdb) set osabi ...".  Handled by gdbarch_lookup_osabi.  */
   if (info->osabi == GDB_OSABI_UNINITIALIZED)
     info->osabi = gdbarch_lookup_osabi (info->abfd);
-  if (info->osabi == GDB_OSABI_UNINITIALIZED
-      && gdbarch != NULL)
-    info->osabi = gdbarch_osabi (gdbarch);
 
   /* Must have at least filled in the architecture.  */
   gdb_assert (info->bfd_arch_info != NULL);

gdb/arch-utils.h

@@ -126,10 +126,6 @@ extern int generic_instruction_nullified (struct gdbarch *gdbarch,
 
 extern int legacy_register_sim_regno (int regnum);
 
-/* Return the selected byte order, or BFD_ENDIAN_UNKNOWN if no byte
-   order was explicitly selected.  */
-extern enum bfd_endian selected_byte_order (void);
-
 /* Return the selected architecture's name, or NULL if no architecture
    was explicitly selected.  */
 extern const char *selected_architecture_name (void);
@@ -141,10 +137,9 @@ extern const char *selected_architecture_name (void);
 extern void gdbarch_info_init (struct gdbarch_info *info);
 
 /* Similar to init, but this time fill in the blanks.  Information is
-   obtained from the specified architecture, global "set ..." options,
-   and explicitly initialized INFO fields.  */
-extern void gdbarch_info_fill (struct gdbarch *gdbarch,
-			       struct gdbarch_info *info);
+   obtained from the global "set ..." options and explicitly
+   initialized INFO fields.  */
+extern void gdbarch_info_fill (struct gdbarch_info *info);
 
 /* Return the architecture for ABFD.  If no suitable architecture
    could be find, return NULL.  */

gdb/doc/ChangeLog

@@ -1,3 +1,8 @@
+2006-11-10  Daniel Jacobowitz  <dan@codesourcery.com>
+
+	* gdbint.texinfo (Target Architecture Definition): Add new
+	Initializing a New Architecture section.
+
 2006-10-31  David Taylor  <dtaylor@emc.com>
 
 	* stabs.texinfo (Macro define and undefine): New node describing

gdb/doc/gdbint.texinfo

@@ -2722,6 +2722,41 @@ architecture, a warning will be issued and the debugging session will continue
 with the defaults already established for @var{gdbarch}.
 @end deftypefun
 
+@section Initializing a New Architecture
+
+Each @code{gdbarch} is associated with a single @sc{bfd} architecture,
+via a @code{bfd_arch_@var{arch}} constant.  The @code{gdbarch} is
+registered by a call to @code{register_gdbarch_init}, usually from
+the file's @code{_initialize_@var{filename}} routine, which will
+be automatically called during @value{GDBN} startup.  The arguments
+are a @sc{bfd} architecture constant and an initialization function.
+
+The initialization function has this type:
+
+@smallexample
+static struct gdbarch *
+@var{arch}_gdbarch_init (struct gdbarch_info @var{info},
+                         struct gdbarch_list *@var{arches})
+@end smallexample
+
+The @var{info} argument contains parameters used to select the correct
+architecture, and @var{arches} is a list of architectures which
+have already been created with the same @code{bfd_arch_@var{arch}}
+value.
+
+The initialization function should first make sure that @var{info}
+is acceptable, and return @code{NULL} if it is not.  Then, it should
+search through @var{arches} for an exact match to @var{info}, and
+return one if found.  Lastly, if no exact match was found, it should
+create a new architecture based on @var{info} and return it.
+
+Only information in @var{info} should be used to choose the new
+architecture.  Historically, @var{info} could be sparse, and
+defaults would be collected from the first element on @var{arches}.
+However, @value{GDBN} now fills in @var{info} more thoroughly,
+so new @code{gdbarch} initialization functions should not take
+defaults from @var{arches}.
+
 @section Registers and Memory
 
 @value{GDBN}'s model of the target machine is rather simple.

gdb/exec.c

@@ -188,6 +188,8 @@ exec_file_attach (char *filename, int from_tty)
     {
       if (from_tty)
         printf_unfiltered (_("No executable file now.\n"));
+
+      set_gdbarch_from_file (NULL);
     }
   else
     {

gdb/gdbarch.c

@@ -3987,7 +3987,7 @@ gdbarch_list_lookup_by_info (struct gdbarch_list *arches,
    that there is no current architecture.  */
 
 static struct gdbarch *
-find_arch_by_info (struct gdbarch *old_gdbarch, struct gdbarch_info info)
+find_arch_by_info (struct gdbarch_info info)
 {
   struct gdbarch *new_gdbarch;
   struct gdbarch_registration *rego;
@@ -3997,9 +3997,9 @@ find_arch_by_info (struct gdbarch *old_gdbarch, struct gdbarch_info info)
   gdb_assert (current_gdbarch == NULL);
 
   /* Fill in missing parts of the INFO struct using a number of
-     sources: "set ..."; INFOabfd supplied; and the existing
-     architecture.  */
-  gdbarch_info_fill (old_gdbarch, &info);
+     sources: "set ..."; INFOabfd supplied; and the global
+     defaults.  */
+  gdbarch_info_fill (&info);
 
   /* Must have found some sort of architecture. */
   gdb_assert (info.bfd_arch_info != NULL);
@@ -4130,7 +4130,7 @@ gdbarch_find_by_info (struct gdbarch_info info)
   struct gdbarch *old_gdbarch = current_gdbarch_swap_out_hack ();
 
   /* Find the specified architecture.  */
-  struct gdbarch *new_gdbarch = find_arch_by_info (old_gdbarch, info);
+  struct gdbarch *new_gdbarch = find_arch_by_info (info);
 
   /* Restore the existing architecture.  */
   gdb_assert (current_gdbarch == NULL);

gdb/gdbarch.h

@@ -1420,8 +1420,7 @@ extern struct gdbarch_tdep *gdbarch_tdep (struct gdbarch *gdbarch);
    ``struct gdbarch'' for this architecture.
 
    The INFO parameter is, as far as possible, be pre-initialized with
-   information obtained from INFO.ABFD or the previously selected
-   architecture.
+   information obtained from INFO.ABFD or the global defaults.
 
    The ARCHES parameter is a linked list (sorted most recently used)
    of all the previously created architures for this architecture

gdb/gdbarch.sh

@@ -943,8 +943,7 @@ extern struct gdbarch_tdep *gdbarch_tdep (struct gdbarch *gdbarch);
    \`\`struct gdbarch'' for this architecture.
 
    The INFO parameter is, as far as possible, be pre-initialized with
-   information obtained from INFO.ABFD or the previously selected
-   architecture.
+   information obtained from INFO.ABFD or the global defaults.
 
    The ARCHES parameter is a linked list (sorted most recently used)
    of all the previously created architures for this architecture
@@ -2050,7 +2049,7 @@ gdbarch_list_lookup_by_info (struct gdbarch_list *arches,
    that there is no current architecture.  */
 
 static struct gdbarch *
-find_arch_by_info (struct gdbarch *old_gdbarch, struct gdbarch_info info)
+find_arch_by_info (struct gdbarch_info info)
 {
   struct gdbarch *new_gdbarch;
   struct gdbarch_registration *rego;
@@ -2060,9 +2059,9 @@ find_arch_by_info (struct gdbarch *old_gdbarch, struct gdbarch_info info)
   gdb_assert (current_gdbarch == NULL);
 
   /* Fill in missing parts of the INFO struct using a number of
-     sources: "set ..."; INFOabfd supplied; and the existing
-     architecture.  */
-  gdbarch_info_fill (old_gdbarch, &info);
+     sources: "set ..."; INFOabfd supplied; and the global
+     defaults.  */
+  gdbarch_info_fill (&info);
 
   /* Must have found some sort of architecture. */
   gdb_assert (info.bfd_arch_info != NULL);
@@ -2193,7 +2192,7 @@ gdbarch_find_by_info (struct gdbarch_info info)
   struct gdbarch *old_gdbarch = current_gdbarch_swap_out_hack ();
 
   /* Find the specified architecture.  */
-  struct gdbarch *new_gdbarch = find_arch_by_info (old_gdbarch, info);
+  struct gdbarch *new_gdbarch = find_arch_by_info (info);
 
   /* Restore the existing architecture.  */
   gdb_assert (current_gdbarch == NULL);

gdb/remote-sim.c

@@ -506,7 +506,7 @@ gdbsim_open (char *args, int from_tty)
   strcpy (arg_buf, "gdbsim");	/* 7 */
   /* Specify the byte order for the target when it is both selectable
      and explicitly specified by the user (not auto detected). */
-  switch (selected_byte_order ())
+  switch (TARGET_BYTE_ORDER)
     {
     case BFD_ENDIAN_BIG:
       strcat (arg_buf, " -E big");