* corelow.c (core_open): Assume there was no upper layer left

behind from a previous inferior.
	* target.c (pop_all_targets): Rename to ...
	(pop_all_targets_above): ... this.  Add a target stratum
	parameter.  Use it instead of hardcoding the dummy_stratum.
	(pop_all_targets): New, defer to pop_all_targets_above.
	(target_preopen): Use pop_all_targets_above.
	* target.h (pop_all_targets_above): Declare.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2008-08-18  Pedro Alves  <pedro@codesourcery.com>
+
+	* corelow.c (core_open): Assume there was no upper layer left
+	behind from a previous inferior.
+	* target.c (pop_all_targets): Rename to ...
+	(pop_all_targets_above): ... this.  Add a target stratum
+	parameter.  Use it instead of hardcoding the dummy_stratum.
+	(pop_all_targets): New, defer to pop_all_targets_above.
+	(target_preopen): Use pop_all_targets_above.
+	* target.h (pop_all_targets_above): Declare.
+
 2008-08-18  Pedro Alves  <pedro@codesourcery.com>
 
 	* gdbthread.h (thread_change_ptid): Declare.

gdb/corelow.c

@@ -258,7 +258,6 @@ core_open (char *filename, int from_tty)
   struct cleanup *old_chain;
   char *temp;
   bfd *temp_bfd;
-  int ontop;
   int scratch_chan;
   int flags;
 
@@ -341,7 +340,7 @@ core_open (char *filename, int from_tty)
   if (!exec_bfd)
     set_gdbarch_from_file (core_bfd);
 
-  ontop = !push_target (&core_ops);
+  push_target (&core_ops);
   discard_cleanups (old_chain);
 
   /* This is done first, before anything has a chance to query the
@@ -368,21 +367,12 @@ core_open (char *filename, int from_tty)
   bfd_map_over_sections (core_bfd, add_to_thread_list,
 			 bfd_get_section_by_name (core_bfd, ".reg"));
 
-  if (ontop)
-    {
-      /* Fetch all registers from core file.  */
-      target_fetch_registers (get_current_regcache (), -1);
+  /* Fetch all registers from core file.  */
+  target_fetch_registers (get_current_regcache (), -1);
 
-      /* Now, set up the frame cache, and print the top of stack.  */
-      reinit_frame_cache ();
-      print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
-    }
-  else
-    {
-      warning (
-		"you won't be able to access this core file until you terminate\n\
-your %s; do ``info files''", target_longname);
-    }
+  /* Now, set up the frame cache, and print the top of stack.  */
+  reinit_frame_cache ();
+  print_stack_frame (get_selected_frame (NULL), 1, SRC_AND_LOC);
 }
 
 static void

gdb/target.c

@@ -822,9 +822,9 @@ pop_target (void)
 }
 
 void
-pop_all_targets (int quitting)
+pop_all_targets_above (enum strata above_stratum, int quitting)
 {
-  while ((int) (current_target.to_stratum) > (int) dummy_stratum)
+  while ((int) (current_target.to_stratum) > (int) above_stratum)
     {
       target_close (&current_target, quitting);
       if (!unpush_target (target_stack))
@@ -839,6 +839,12 @@ pop_all_targets (int quitting)
     }
 }
 
+void
+pop_all_targets (int quitting)
+{
+  pop_all_targets_above (dummy_stratum, quitting);
+}
+
 /* Using the objfile specified in OBJFILE, find the address for the
    current thread's thread-local storage with offset OFFSET.  */
 CORE_ADDR
@@ -1778,9 +1784,9 @@ target_preopen (int from_tty)
 
   /* Calling target_kill may remove the target from the stack.  But if
      it doesn't (which seems like a win for UDI), remove it now.  */
-
-  if (target_has_execution)
-    pop_target ();
+  /* Leave the exec target, though.  The user may be switching from a
+     live process to a core of the same program.  */
+  pop_all_targets_above (file_stratum, 0);
 
   target_pre_inferior (from_tty);
 }

gdb/target.h

@@ -1179,6 +1179,10 @@ extern void pop_target (void);
    while).  */
 extern void pop_all_targets (int quitting);
 
+/* Like pop_all_targets, but pops only targets whose stratum is
+   strictly above ABOVE_STRATUM.  */
+extern void pop_all_targets_above (enum strata above_stratum, int quitting);
+
 extern CORE_ADDR target_translate_tls_address (struct objfile *objfile,
 					       CORE_ADDR offset);