[PATCH 6/8] Make reinsert_breakpoint thread specific

[Yao Qi <qiyaoltc at gmail dot com>]

This patch makes reinsert_breakpoint thread specific, which means we
insert and remove reinsert_breakpoint breakpoints for a specific
thread.  This motivation of this change is that I'll use
reinsert_breakpoint for vCont;s on software single step target, so that
GDBserver may insert one reinsert_breakpoint for step-over, and the
other one for vCont;s.  After the operation of one thread is finished,
GDBserver must remove reinsert_breakpoint for that thread only.

On the other hand, reinsert_breakpoint is used for step-over nowadays,
which is an operation to one thread in one go.  In other words,
reinsert_breakpoint is globally thread specific, but in an implicit way.
It is natural to make it explicitly thread specific.

gdb/gdbserver:

2016-05-20  Yao Qi  <yao.qi@linaro.org>

	* mem-break.c (struct reinsert_breakpoint) <id>: New field.
	(set_reinsert_breakpoint): New parameter id.  Callers updated.
	(delete_reinsert_breakpoints): Likewise.
	(has_reinsert_breakpoints): Change parameter to thread.  Callers
	updated.
	(clone_one_breakpoint): Likewise.
---
 gdb/gdbserver/linux-low.c | 16 ++++++++--------
 gdb/gdbserver/mem-break.c | 34 +++++++++++++++++++++++++---------
 gdb/gdbserver/mem-break.h | 13 +++++++------
 3 files changed, 40 insertions(+), 23 deletions(-)

diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 539d787..d5f7097 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -578,11 +578,11 @@ handle_extended_wait (struct lwp_info **orig_event_lwp, int wstat)
 		 to access its memory without stopping all other threads
 		 from other processes.  */
 	      current_thread = child_thr;
-	      delete_reinsert_breakpoints ();
+	      delete_reinsert_breakpoints (ptid);
 	      current_thread = saved_thread;
 
-	      gdb_assert (has_reinsert_breakpoints (parent_proc));
-	      gdb_assert (!has_reinsert_breakpoints (child_proc));
+	      gdb_assert (has_reinsert_breakpoints (event_thr));
+	      gdb_assert (!has_reinsert_breakpoints (child_thr));
 	    }
 
 	  /* Report the event.  */
@@ -4097,7 +4097,7 @@ install_software_single_step_breakpoints (struct lwp_info *lwp)
   next_pcs = (*the_low_target.get_next_pcs) (regcache);
 
   for (i = 0; VEC_iterate (CORE_ADDR, next_pcs, i, pc); ++i)
-    set_reinsert_breakpoint (pc);
+    set_reinsert_breakpoint (pc, current_ptid);
 
   do_cleanups (old_chain);
 }
@@ -4238,7 +4238,7 @@ linux_resume_one_lwp_throw (struct lwp_info *lwp,
       else
 	{
 	  gdb_assert (step == 0);
-	  gdb_assert (has_reinsert_breakpoints (proc));
+	  gdb_assert (has_reinsert_breakpoints (thread));
 	}
     }
 
@@ -4728,8 +4728,8 @@ finish_step_over (struct lwp_info *lwp)
 	 threads but LWP stopped while doing that.  */
       if (!can_hardware_single_step ())
 	{
-	  gdb_assert (has_reinsert_breakpoints (current_process ()));
-	  delete_reinsert_breakpoints ();
+	  gdb_assert (has_reinsert_breakpoints (get_lwp_thread (lwp)));
+	  delete_reinsert_breakpoints (ptid_of_lwp (lwp));
 	}
 
       step_over_bkpt = null_ptid;
@@ -5067,7 +5067,7 @@ proceed_one_lwp (struct inferior_list_entry *entry, void *except)
       else
 	{
 	  /* GDBserver must insert reinsert breakpoint for step-over.  */
-	  gdb_assert (has_reinsert_breakpoints (get_thread_process (thread)));
+	  gdb_assert (has_reinsert_breakpoints (thread));
 	}
     }
 
diff --git a/gdb/gdbserver/mem-break.c b/gdb/gdbserver/mem-break.c
index 4e45c0e..5d699c3 100644
--- a/gdb/gdbserver/mem-break.c
+++ b/gdb/gdbserver/mem-break.c
@@ -211,6 +211,9 @@ struct other_breakpoint
 struct reinsert_breakpoint
 {
   struct breakpoint base;
+
+  /* Thread the reinsert breakpoint belongs to.  */
+  ptid_t id;
 };
 
 /* Return the breakpoint size from its kind.  */
@@ -1476,25 +1479,32 @@ gdb_breakpoint_here (CORE_ADDR where)
 }
 
 void
-set_reinsert_breakpoint (CORE_ADDR stop_at)
+set_reinsert_breakpoint (CORE_ADDR stop_at, ptid_t id)
 {
-  struct breakpoint *bp;
+  struct reinsert_breakpoint *bp;
 
-  bp = set_breakpoint_at_1 (reinsert_breakpoint, stop_at, NULL);
+  gdb_assert (ptid_get_pid (current_ptid) == ptid_get_pid (id));
+
+  bp = (struct reinsert_breakpoint *) set_breakpoint_at_1 (reinsert_breakpoint,
+							   stop_at, NULL);
+  bp->id = id;
 }
 
 void
-delete_reinsert_breakpoints (void)
+delete_reinsert_breakpoints (ptid_t id)
 {
   struct process_info *proc = current_process ();
   struct breakpoint *bp, **bp_link;
 
+  gdb_assert (ptid_get_pid (current_ptid) == ptid_get_pid (id));
+
   bp = proc->breakpoints;
   bp_link = &proc->breakpoints;
 
   while (bp)
     {
-      if (bp->type == reinsert_breakpoint)
+      if (bp->type == reinsert_breakpoint
+	  && ptid_equal (((struct reinsert_breakpoint *) bp)->id, id))
 	{
 	  *bp_link = bp->next;
 	  release_breakpoint (proc, bp);
@@ -1622,8 +1632,9 @@ reinsert_breakpoints_at (CORE_ADDR pc)
 }
 
 int
-has_reinsert_breakpoints (struct process_info *proc)
+has_reinsert_breakpoints (struct thread_info *thread)
 {
+  struct process_info *proc = get_thread_process (thread);
   struct breakpoint *bp, **bp_link;
 
   bp = proc->breakpoints;
@@ -1631,7 +1642,9 @@ has_reinsert_breakpoints (struct process_info *proc)
 
   while (bp)
     {
-      if (bp->type == reinsert_breakpoint)
+      if (bp->type == reinsert_breakpoint
+	  && ptid_equal (((struct reinsert_breakpoint *) bp)->id,
+			 ptid_of (thread)))
 	return 1;
       else
 	{
@@ -2070,7 +2083,7 @@ clone_agent_expr (const struct agent_expr *src_ax)
 /* Deep-copy the contents of one breakpoint to another.  */
 
 static struct breakpoint *
-clone_one_breakpoint (const struct breakpoint *src)
+clone_one_breakpoint (const struct breakpoint *src, ptid_t id)
 {
   struct breakpoint *dest;
   struct raw_breakpoint *dest_raw;
@@ -2131,6 +2144,9 @@ clone_one_breakpoint (const struct breakpoint *src)
 	= XCNEW (struct reinsert_breakpoint);
 
       dest = (struct breakpoint *) reinsert_dest;
+      /* Since reinsert breakpoint is thread specific, don't copy
+	 thread id from SRC, use ID instead.  */
+      reinsert_dest->id = id;
     }
   else
     gdb_assert_not_reached ("unhandled breakpoint type");
@@ -2157,7 +2173,7 @@ clone_all_breakpoints (struct thread_info *child_thread,
 
   for (bp = parent_proc->breakpoints; bp != NULL; bp = bp->next)
     {
-      new_bkpt = clone_one_breakpoint (bp);
+      new_bkpt = clone_one_breakpoint (bp, ptid_of (child_thread));
       APPEND_TO_LIST (new_list, new_bkpt, bkpt_tail);
       APPEND_TO_LIST (new_raw_list, new_bkpt->raw, raw_bkpt_tail);
     }
diff --git a/gdb/gdbserver/mem-break.h b/gdb/gdbserver/mem-break.h
index 757399a..38d5911 100644
--- a/gdb/gdbserver/mem-break.h
+++ b/gdb/gdbserver/mem-break.h
@@ -152,22 +152,23 @@ struct breakpoint *set_breakpoint_at (CORE_ADDR where,
 
 int delete_breakpoint (struct breakpoint *bkpt);
 
-/* Set a reinsert breakpoint at STOP_AT.  */
+/* Set a reinsert breakpoint at STOP_AT for thread represented by
+   ID.  */
 
-void set_reinsert_breakpoint (CORE_ADDR stop_at);
+void set_reinsert_breakpoint (CORE_ADDR stop_at, ptid_t id);
 
-/* Delete all reinsert breakpoints.  */
+/* Delete all reinsert breakpoints of thread represented by ID.  */
 
-void delete_reinsert_breakpoints (void);
+void delete_reinsert_breakpoints (ptid_t id);
 
 /* Reinsert breakpoints at WHERE (and change their status to
    inserted).  */
 
 void reinsert_breakpoints_at (CORE_ADDR where);
 
-/* Process PROC has reinsert breakpoints or not.  */
+/* The THREAD has reinsert breakpoints or not.  */
 
-int has_reinsert_breakpoints (struct process_info *proc);
+int has_reinsert_breakpoints (struct thread_info *thread);
 
 /* Uninsert breakpoints at WHERE (and change their status to
    uninserted).  This still leaves the breakpoints in the table.  */
-- 
1.9.1