Make single-step breakpoints be per-thread

This patch finally makes each thread have its own set of single-step
breakpoints.  This paves the way to have multiple threads software
single-stepping, though this patch doesn't flip that switch on yet.
That'll be done on a subsequent patch.

gdb/
2014-10-15  Pedro Alves  <palves@redhat.com>

	* breakpoint.c (single_step_breakpoints): Delete global.
	(insert_single_step_breakpoint): Adjust to store the breakpoint
	pointer in the current thread.
	(single_step_breakpoints_inserted, remove_single_step_breakpoints)
	(cancel_single_step_breakpoints): Delete functions.
	(breakpoint_has_location_inserted_here): Make extern.
	(single_step_breakpoint_inserted_here_p): Adjust to walk the
	breakpoint list.
	* breakpoint.h (breakpoint_has_location_inserted_here): New
	declaration.
	(single_step_breakpoints_inserted, remove_single_step_breakpoints)
	(cancel_single_step_breakpoints): Remove declarations.
	* gdbthread.h (struct thread_control_state)
	<single_step_breakpoints>: New field.
	(delete_single_step_breakpoints)
	(thread_has_single_step_breakpoints_set)
	(thread_has_single_step_breakpoint_here): New declarations.
	* infrun.c (follow_exec): Also clear the single-step breakpoints.
	(singlestep_breakpoints_inserted_p, singlestep_ptid)
	(singlestep_pc): Delete globals.
	(infrun_thread_ptid_changed): Remove references to removed
	globals.
	(resume_cleanups): Delete the current thread's single-step
	breakpoints.
	(maybe_software_singlestep): Remove references to removed globals.
	(resume): Adjust to use thread_has_single_step_breakpoints_set and
	delete_single_step_breakpoints.
	(init_wait_for_inferior): Remove references to removed globals.
	(delete_thread_infrun_breakpoints): Delete the thread's
	single-step breakpoints too.
	(delete_just_stopped_threads_infrun_breakpoints): Don't delete
	single-step breakpoints here.
	(delete_stopped_threads_single_step_breakpoints): New function.
	(adjust_pc_after_break): Adjust to use
	thread_has_single_step_breakpoints_set.
	(handle_inferior_event): Remove references to removed globals.
	Use delete_stopped_threads_single_step_breakpoints.
	(handle_signal_stop): Adjust to per-thread single-step
	breakpoints.  Swap test order to do cheaper tests first.
	(switch_back_to_stepped_thread): Extend debug output.  Remove
	references to removed globals.
	* record-full.c (record_full_wait_1): Adjust to per-thread
	single-step breakpoints.
	* thread.c (delete_single_step_breakpoints)
	(thread_has_single_step_breakpoints_set)
	(thread_has_single_step_breakpoint_here): New functions.
	(clear_thread_inferior_resources): Also delete the thread's
	single-step breakpoints.

1 files changed, 20 insertions, 0 deletions

diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index 36ad5a7..178fd4a 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -52,6 +52,13 @@ struct thread_control_state
   /* Exception-resume breakpoint.  */
   struct breakpoint *exception_resume_breakpoint;
 
+  /* Breakpoints used for software single stepping.  Plural, because
+     it may have multiple locations.  E.g., if stepping over a
+     conditional branch instruction we can't decode the condition for,
+     we'll need to put a breakpoint at the branch destination, and
+     another at the instruction after the branch.  */
+  struct breakpoint *single_step_breakpoints;
+
   /* Range to single step within.
 
      If this is nonzero, respond to a single-step signal by continuing
@@ -285,6 +292,19 @@ extern void delete_step_resume_breakpoint (struct thread_info *);
 /* Delete an exception_resume_breakpoint from the thread database.  */
 extern void delete_exception_resume_breakpoint (struct thread_info *);
 
+/* Delete the single-step breakpoints of thread TP, if any.  */
+extern void delete_single_step_breakpoints (struct thread_info *tp);
+
+/* Check if the thread has software single stepping breakpoints
+   set.  */
+extern int thread_has_single_step_breakpoints_set (struct thread_info *tp);
+
+/* Check whether the thread has software single stepping breakpoints
+   set at PC.  */
+extern int thread_has_single_step_breakpoint_here (struct thread_info *tp,
+						   struct address_space *aspace,
+						   CORE_ADDR addr);
+
 /* Translate the integer thread id (GDB's homegrown id, not the system's)
    into a "pid" (which may be overloaded with extra thread information).  */
 extern ptid_t thread_id_to_pid (int);