Remove context switching in favour of accessing thread_info fields

	directly.

	* infrun.c (stepping_over_breakpoint, step_resume_breakpoint):
	Delete.
	(struct thread_stepping_state): Delete.
	(gtss, tss): Delete.
	(follow_inferior_reset_breakpoints, follow_exec)
	(resume, clear_proceed_status): Adjust.
	(prev_pc): Delete.
	(proceed, start_remote, init_wait_for_inferior): Adjust.
	(struct execution_control_state): Add event_thread member.
	(delete_step_resume_breakpoint_callback)
	(delete_step_thread_step_resume_breakpoint)
	(delete_step_thread_step_resume_breakpoint_cleanup)
	(delete_step_thread_step_resume_breakpoint): New.
	(wait_for_inferior, init_execution_control_state): Use
	delete_step_thread_step_resume_breakpoint_cleanup.
	(wait_for_inferior): Set the event_thread.
	(fetch_inferior_event): Ditto.  Delete the step-resume breakpoint
	with delete_step_thread_step_resume_breakpoint.
	(init_thread_stepping_state): Change parameter type to
	thread_info.  Adjust.
	(context_switch): Don't context switch prev_pc,
	stepping_over_breakpoint, step_resume_breakpoint,
	step_range_start, step_range_end, step_frame_id,
	tss->stepping_over_breakpoint,
	tss->stepping_through_solib_after_catch,
	tss->stepping_through_solib_catchpoints, tss->current_line, or
	tss->current_symtab.
	(adjust_pc_after_break, handle_inferior_event)
	(currently_stepping, step_into_function)
	(insert_step_resume_breakpoint_at_sal)
	(insert_longjmp_resume_breakpoint, keep_going): Adjust.
	(clear_stepping_state): New.
	(normal_stop): Adjust.
	(save_inferior_status, restore_inferior_status): Adjust.

	* gdbthread.h (struct thread_info): Comments describing the
	members moved here.  Add step_after_step_resume_breakpoint.
	(delete_step_resume_breakpoint): Add thread_info argument.
	(save_infrun_state, load_infrun_state): Remove prev_pc,
	trap_expected, step_resume_breakpoint, step_range_start,
	step_range_end, step_frame_id, another_trap,
	stepping_through_solib_after_catch,
	stepping_through_solib_catchpoints, current_line and
	current_symtab function arguments.
	(inferior_thread): Declare.

	* thread.c (inferior_thread): New.
	(delete_step_resume_breakpoint): Add a thread_info parameter and
	rewrite.
	(load_infrun_state, save_infrun_state): Remove prev_pc,
	trap_expected, step_resume_breakpoint, step_range_start,
	step_range_end, step_frame_id, stepping_over_breakpoint,
	stepping_through_solib_after_catch,
	stepping_through_solib_catchpoints, current_line and
	current_symtab args.  Remove code referencing them.

	* infcmd.c (step_range_start, step_range_end, step_frame_id):
	Delete.
	(step_1, step_once, until_next_command): Adjust.

	* inferior.h (step_range_start, step_range_end, step_frame_id):
	Delete.

	* linux-nat.c (linux_child_follow_fork): If following the child,
	move the step state to it.  Adjust.
	* inf-ptrace.c (inf_ptrace_follow_fork): Ditto.
	* inf-ttrace.c (inf_ttrace_follow_fork): Ditto.

1 files changed, 31 insertions, 4 deletions

diff --git a/gdb/inf-ptrace.c b/gdb/inf-ptrace.c
index 6899be0..301d59d 100644
--- a/gdb/inf-ptrace.c
+++ b/gdb/inf-ptrace.c
@@ -46,6 +46,7 @@ inf_ptrace_follow_fork (struct target_ops *ops, int follow_child)
 {
   pid_t pid, fpid;
   ptrace_state_t pe;
+  struct thread_info *last_tp = NULL;
 
   /* FIXME: kettenis/20050720: This stuff should really be passed as
      an argument by our caller.  */
@@ -57,6 +58,7 @@ inf_ptrace_follow_fork (struct target_ops *ops, int follow_child)
     gdb_assert (status.kind == TARGET_WAITKIND_FORKED);
 
     pid = ptid_get_pid (ptid);
+    last_tp = find_thread_pid (ptid);
   }
 
   if (ptrace (PT_GET_PROCESS_STATE, pid,
@@ -68,14 +70,39 @@ inf_ptrace_follow_fork (struct target_ops *ops, int follow_child)
 
   if (follow_child)
     {
-      inferior_ptid = pid_to_ptid (fpid);
-      detach_breakpoints (pid);
+      /* Copy user stepping state to the new inferior thread.  */
+      struct breakpoint *step_resume_breakpoint = last_tp->step_resume_breakpoint;
+      CORE_ADDR step_range_start = last_tp->step_range_start;
+      CORE_ADDR step_range_end = last_tp->step_range_end;
+      struct frame_id step_frame_id = last_tp->step_frame_id;
 
-      /* Reset breakpoints in the child as appropriate.  */
-      follow_inferior_reset_breakpoints ();
+      struct thread_info *tp;
+
+      /* Otherwise, deleting the parent would get rid of this
+	 breakpoint.  */
+      last_tp->step_resume_breakpoint = NULL;
+
+      /* Before detaching from the parent, remove all breakpoints from
+	 it.  */
+      detach_breakpoints (pid);
 
       if (ptrace (PT_DETACH, pid, (PTRACE_TYPE_ARG3)1, 0) == -1)
 	perror_with_name (("ptrace"));
+
+      /* Delete the parent.  */
+      delete_thread_silent (last_tp->ptid);
+
+      /* Add the child.  */
+      inferior_ptid = pid_to_ptid (fpid);
+      tp = add_thread_silent (inferior_ptid);
+
+      tp->step_resume_breakpoint = step_resume_breakpoint;
+      tp->step_range_start = step_range_start;
+      tp->step_range_end = step_range_end;
+      tp->step_frame_id = step_frame_id;
+
+      /* Reset breakpoints in the child as appropriate.  */
+      follow_inferior_reset_breakpoints ();
     }
   else
     {