target: add to_record_will_replay target method

Add a new target method to_record_will_replay to query if there is a record
target that will replay at least one thread matching the argument PTID if it
were executed in the argument execution direction.

gdb/
	* record-btrace.c ((record_btrace_will_replay): New.
	(init_record_btrace_ops): Initialize to_record_will_replay.
	* record-full.c ((record_full_will_replay): New.
	(init_record_full_ops): Initialize to_record_will_replay.
	* target-delegates.c: Regenerated.
	* target.c (target_record_will_replay): New.
	* target.h (struct target_ops) <to_record_will_replay>: New.
	(target_record_will_replay): New.

Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>

6 files changed, 85 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 24ae06a..a2bd843 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,16 @@
 2015-09-18  Markus Metzger  <markus.t.metzger@intel.com>
 
+	* record-btrace.c ((record_btrace_will_replay): New.
+	(init_record_btrace_ops): Initialize to_record_will_replay.
+	* record-full.c ((record_full_will_replay): New.
+	(init_record_full_ops): Initialize to_record_will_replay.
+	* target-delegates.c: Regenerated.
+	* target.c (target_record_will_replay): New.
+	* target.h (struct target_ops) <to_record_will_replay>: New.
+	(target_record_will_replay): New.
+
+2015-09-18  Markus Metzger  <markus.t.metzger@intel.com>
+
 	* record-btrace.c (record_btrace_resume): Call
 	target_record_stop_replaying.
 	(record_btrace_stop_replaying_all): New.
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index e0b79a8..df15d77 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1147,6 +1147,14 @@ record_btrace_is_replaying (struct target_ops *self, ptid_t ptid)
   return 0;
 }
 
+/* The to_record_will_replay method of target record-btrace.  */
+
+static int
+record_btrace_will_replay (struct target_ops *self, ptid_t ptid, int dir)
+{
+  return dir == EXEC_REVERSE || record_btrace_is_replaying (self, ptid);
+}
+
 /* The to_xfer_partial method of target record-btrace.  */
 
 static enum target_xfer_status
@@ -2657,6 +2665,7 @@ init_record_btrace_ops (void)
   ops->to_call_history_from = record_btrace_call_history_from;
   ops->to_call_history_range = record_btrace_call_history_range;
   ops->to_record_is_replaying = record_btrace_is_replaying;
+  ops->to_record_will_replay = record_btrace_will_replay;
   ops->to_record_stop_replaying = record_btrace_stop_replaying_all;
   ops->to_xfer_partial = record_btrace_xfer_partial;
   ops->to_remove_breakpoint = record_btrace_remove_breakpoint;
diff --git a/gdb/record-full.c b/gdb/record-full.c
index 35b3841..cb05437 100644
--- a/gdb/record-full.c
+++ b/gdb/record-full.c
@@ -1845,6 +1845,18 @@ record_full_is_replaying (struct target_ops *self, ptid_t ptid)
   return RECORD_FULL_IS_REPLAY;
 }
 
+/* The "to_record_will_replay" target method.  */
+
+static int
+record_full_will_replay (struct target_ops *self, ptid_t ptid, int dir)
+{
+  /* We can currently only record when executing forwards.  Should we be able
+     to record when executing backwards on targets that support reverse
+     execution, this needs to be changed.  */
+
+  return RECORD_FULL_IS_REPLAY || dir == EXEC_REVERSE;
+}
+
 /* Go to a specific entry.  */
 
 static void
@@ -1965,6 +1977,7 @@ init_record_full_ops (void)
   record_full_ops.to_save_record = record_full_save;
   record_full_ops.to_delete_record = record_full_delete;
   record_full_ops.to_record_is_replaying = record_full_is_replaying;
+  record_full_ops.to_record_will_replay = record_full_will_replay;
   record_full_ops.to_record_stop_replaying = record_full_stop_replaying;
   record_full_ops.to_goto_record_begin = record_full_goto_begin;
   record_full_ops.to_goto_record_end = record_full_goto_end;
@@ -2212,6 +2225,7 @@ init_record_full_core_ops (void)
   record_full_core_ops.to_info_record = record_full_info;
   record_full_core_ops.to_delete_record = record_full_delete;
   record_full_core_ops.to_record_is_replaying = record_full_is_replaying;
+  record_full_core_ops.to_record_will_replay = record_full_will_replay;
   record_full_core_ops.to_goto_record_begin = record_full_goto_begin;
   record_full_core_ops.to_goto_record_end = record_full_goto_end;
   record_full_core_ops.to_goto_record = record_full_goto;
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index a07c8c9..a7271fa 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -3630,6 +3630,37 @@ debug_record_is_replaying (struct target_ops *self, ptid_t arg1)
   return result;
 }
 
+static int
+delegate_record_will_replay (struct target_ops *self, ptid_t arg1, int arg2)
+{
+  self = self->beneath;
+  return self->to_record_will_replay (self, arg1, arg2);
+}
+
+static int
+tdefault_record_will_replay (struct target_ops *self, ptid_t arg1, int arg2)
+{
+  return 0;
+}
+
+static int
+debug_record_will_replay (struct target_ops *self, ptid_t arg1, int arg2)
+{
+  int result;
+  fprintf_unfiltered (gdb_stdlog, "-> %s->to_record_will_replay (...)\n", debug_target.to_shortname);
+  result = debug_target.to_record_will_replay (&debug_target, arg1, arg2);
+  fprintf_unfiltered (gdb_stdlog, "<- %s->to_record_will_replay (", debug_target.to_shortname);
+  target_debug_print_struct_target_ops_p (&debug_target);
+  fputs_unfiltered (", ", gdb_stdlog);
+  target_debug_print_ptid_t (arg1);
+  fputs_unfiltered (", ", gdb_stdlog);
+  target_debug_print_int (arg2);
+  fputs_unfiltered (") = ", gdb_stdlog);
+  target_debug_print_int (result);
+  fputs_unfiltered ("\n", gdb_stdlog);
+  return result;
+}
+
 static void
 delegate_record_stop_replaying (struct target_ops *self)
 {
@@ -4289,6 +4320,8 @@ install_delegators (struct target_ops *ops)
     ops->to_delete_record = delegate_delete_record;
   if (ops->to_record_is_replaying == NULL)
     ops->to_record_is_replaying = delegate_record_is_replaying;
+  if (ops->to_record_will_replay == NULL)
+    ops->to_record_will_replay = delegate_record_will_replay;
   if (ops->to_record_stop_replaying == NULL)
     ops->to_record_stop_replaying = delegate_record_stop_replaying;
   if (ops->to_goto_record_begin == NULL)
@@ -4458,6 +4491,7 @@ install_dummy_methods (struct target_ops *ops)
   ops->to_save_record = tdefault_save_record;
   ops->to_delete_record = tdefault_delete_record;
   ops->to_record_is_replaying = tdefault_record_is_replaying;
+  ops->to_record_will_replay = tdefault_record_will_replay;
   ops->to_record_stop_replaying = tdefault_record_stop_replaying;
   ops->to_goto_record_begin = tdefault_goto_record_begin;
   ops->to_goto_record_end = tdefault_goto_record_end;
@@ -4612,6 +4646,7 @@ init_debug_target (struct target_ops *ops)
   ops->to_save_record = debug_save_record;
   ops->to_delete_record = debug_delete_record;
   ops->to_record_is_replaying = debug_record_is_replaying;
+  ops->to_record_will_replay = debug_record_will_replay;
   ops->to_record_stop_replaying = debug_record_stop_replaying;
   ops->to_goto_record_begin = debug_goto_record_begin;
   ops->to_goto_record_end = debug_goto_record_end;
diff --git a/gdb/target.c b/gdb/target.c
index f73067c..8df862b 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3663,6 +3663,14 @@ target_record_is_replaying (ptid_t ptid)
 
 /* See target.h.  */
 
+int
+target_record_will_replay (ptid_t ptid, int dir)
+{
+  return current_target.to_record_will_replay (&current_target, ptid, dir);
+}
+
+/* See target.h.  */
+
 void
 target_record_stop_replaying (void)
 {
diff --git a/gdb/target.h b/gdb/target.h
index 169785d..2b2db45 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1157,6 +1157,11 @@ struct target_ops
     int (*to_record_is_replaying) (struct target_ops *, ptid_t ptid)
       TARGET_DEFAULT_RETURN (0);
 
+    /* Query if the record target will replay PTID if it were resumed in
+       execution direction DIR.  */
+    int (*to_record_will_replay) (struct target_ops *, ptid_t ptid, int dir)
+      TARGET_DEFAULT_RETURN (0);
+
     /* Stop replaying.  */
     void (*to_record_stop_replaying) (struct target_ops *)
       TARGET_DEFAULT_IGNORE ();
@@ -2446,6 +2451,9 @@ extern void target_delete_record (void);
 /* See to_record_is_replaying in struct target_ops.  */
 extern int target_record_is_replaying (ptid_t ptid);
 
+/* See to_record_will_replay in struct target_ops.  */
+extern int target_record_will_replay (ptid_t ptid, int dir);
+
 /* See to_record_stop_replaying in struct target_ops.  */
 extern void target_record_stop_replaying (void);