2005-11-09  Andrew Stubbs  <andrew.stubbs@st.com>

	* sh-tdep.c (backtrace_abi_sniffer): New variable.
	(sh_frame_this_id): Do nothing if backtrace_abi_sniffer zero.
	(sh_gdbarch_init): Add set/show abi-sniffer command.
	* frame.c (set_backtrace_cmdlist): Remove static.
	(show_backtrace_cmdlist): Likewise.
	* frame.h (set_backtrace_cmdlist): Add extern declaration.
	(show_backtrace_cmdlist): Likewise.

doc/
	* gdb.texinfo (Super-H): Add 'set/show backtrace abi-sniffer'.

Index: src/gdb/sh-tdep.c
===================================================================
--- src.orig/gdb/sh-tdep.c	2005-11-01 11:43:29.000000000 +0000
+++ src/gdb/sh-tdep.c	2005-11-01 12:26:24.000000000 +0000
@@ -2377,12 +2377,18 @@ sh_frame_prev_register (struct frame_inf
     frame_unwind_register (next_frame, (*realnump), valuep);
 }
 
+static int backtrace_abi_sniffer = 1;
+
 static void
 sh_frame_this_id (struct frame_info *next_frame, void **this_cache,
 		  struct frame_id *this_id)
 {
   struct sh_frame_cache *cache = sh_frame_cache (next_frame, this_cache);
 
+  /* Is this sniffer enabled? */
+  if (!backtrace_abi_sniffer)
+    return;
+
   /* This marks the outermost frame.  */
   if (cache->base == 0)
     return;
@@ -2726,6 +2732,22 @@ sh_gdbarch_init (struct gdbarch_info inf
   frame_unwind_append_sniffer (gdbarch, dwarf2_frame_sniffer);
   frame_unwind_append_sniffer (gdbarch, sh_frame_sniffer);
 
+  add_setshow_boolean_cmd ("abi-sniffer", class_obscure,
+                           &backtrace_abi_sniffer, "\
+Set whether backtraces should use the ABI where there is no debug info.", "\
+Show whether backtraces should use the ABI where there is no debug info.", "\
+Normally there is debug information from which to construct a backtrace\n\
+but sometimes is is not available (e.g. in assembly code). In this case the\n\
+ABI sniffer can attempt to construct a backtrace. It is disabled by default\n\
+because it can cause inconvenient errors. Note that it does not disable the\n\
+Dwarf debug information sniffer.",
+                           NULL, NULL, &set_backtrace_cmdlist,
+                           &show_backtrace_cmdlist);
+
+#ifdef SVR4_SHARED_LIBS
+  set_solib_svr4_fetch_link_map_offsets (gdbarch, svr4_ilp32_fetch_link_map_offsets);
+#endif
+
   return gdbarch;
 }
 
Index: src/gdb/frame.c
===================================================================
--- src.orig/gdb/frame.c	2005-11-01 11:16:55.000000000 +0000
+++ src/gdb/frame.c	2005-11-01 11:43:29.000000000 +0000
@@ -1558,8 +1558,8 @@ frame_sp_unwind (struct frame_info *next
 
 extern initialize_file_ftype _initialize_frame; /* -Wmissing-prototypes */
 
-static struct cmd_list_element *set_backtrace_cmdlist;
-static struct cmd_list_element *show_backtrace_cmdlist;
+struct cmd_list_element *set_backtrace_cmdlist;
+struct cmd_list_element *show_backtrace_cmdlist;
 
 static void
 set_backtrace_cmd (char *args, int from_tty)
Index: src/gdb/frame.h
===================================================================
--- src.orig/gdb/frame.h	2005-11-01 11:16:55.000000000 +0000
+++ src/gdb/frame.h	2005-11-01 11:43:29.000000000 +0000
@@ -660,4 +660,9 @@ extern void deprecated_update_frame_pc_h
 extern void deprecated_update_frame_base_hack (struct frame_info *frame,
 					       CORE_ADDR base);
 
+/* Export 'set backtrace' so that new subcommands may be added elsewhere. */
+
+extern struct cmd_list_element *set_backtrace_cmdlist;
+extern struct cmd_list_element *show_backtrace_cmdlist;
+
 #endif /* !defined (FRAME_H)  */
Index: src/gdb/doc/gdb.texinfo
===================================================================
--- src.orig/gdb/doc/gdb.texinfo	2005-11-01 11:43:29.000000000 +0000
+++ src/gdb/doc/gdb.texinfo	2005-11-01 12:56:00.000000000 +0000
@@ -14790,8 +14790,21 @@ commands:
 @item regs
 @kindex regs@r{, Super-H}
 Show the values of all Super-H registers.
+
+@item set backtrace abi-sniffer
+@kindex set backtrace abi-sniffer
+This command enables or disables the SH ABI-based frame sniffer. This
+`sniffer' attempts to find the frames of a backtrace when there is no
+debug information (specifically CFI) to do the job properly. Sniffing
+frames is problematic so it is often best to switch this @samp{off}. It
+is @samp{on} by default.
+
+@item show backtrace abi-sniffer
+@kindex show backtrace abi-sniffer
+Show whether the abi-sniffer is enabled, or not.
 @end table
 
+
 @node WinCE
 @subsection Windows CE
 @cindex Windows CE