[RFC v2 38/38] convert to_get_unwinder and to_get_tailcall_unwinder to methods

[Tom Tromey <tromey@redhat.com>]

This converts to_get_unwinder and to_get_tailcall_unwinder to methods
and arranges for them to use the new delegation scheme.

This just lets us avoid having a differing style (neither new-style
nor INHERIT) of delegation in the tree.

2014-02-06  Tom Tromey  <tromey@redhat.com>

	* target.c (target_get_unwinder): Rewrite.
	(target_get_tailcall_unwinder): Rewrite.
	* record-btrace.c (record_btrace_to_get_unwinder): New function.
	(record_btrace_to_get_tailcall_unwinder): New function.
	(init_record_btrace_ops): Update.
	* target.h (struct target_ops) <to_get_unwinder,
	to_get_tailcall_unwinder>: Now function pointers.  Use
	TARGET_DEFAULT_RETURN.
---
 gdb/ChangeLog          | 11 +++++++++++
 gdb/record-btrace.c    | 20 ++++++++++++++++++--
 gdb/target-delegates.c | 32 ++++++++++++++++++++++++++++++++
 gdb/target.c           | 16 ++--------------
 gdb/target.h           | 12 ++++++++----
 5 files changed, 71 insertions(+), 20 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index c4872eb..ab288ef 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1302,6 +1302,22 @@ const struct frame_unwind record_btrace_tailcall_frame_unwind =
   record_btrace_frame_dealloc_cache
 };
 
+/* Implement the to_get_unwinder method.  */
+
+static const struct frame_unwind *
+record_btrace_to_get_unwinder (struct target_ops *self)
+{
+  return &record_btrace_frame_unwind;
+}
+
+/* Implement the to_get_tailcall_unwinder method.  */
+
+static const struct frame_unwind *
+record_btrace_to_get_tailcall_unwinder (struct target_ops *self)
+{
+  return &record_btrace_tailcall_frame_unwind;
+}
+
 /* Indicate that TP should be resumed according to FLAG.  */
 
 static void
@@ -1888,8 +1904,8 @@ init_record_btrace_ops (void)
   ops->to_fetch_registers = record_btrace_fetch_registers;
   ops->to_store_registers = record_btrace_store_registers;
   ops->to_prepare_to_store = record_btrace_prepare_to_store;
-  ops->to_get_unwinder = &record_btrace_frame_unwind;
-  ops->to_get_tailcall_unwinder = &record_btrace_tailcall_frame_unwind;
+  ops->to_get_unwinder = &record_btrace_to_get_unwinder;
+  ops->to_get_tailcall_unwinder = &record_btrace_to_get_tailcall_unwinder;
   ops->to_resume = record_btrace_resume;
   ops->to_wait = record_btrace_wait;
   ops->to_find_new_threads = record_btrace_find_new_threads;
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index d9c68cd..03b0d2a 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -1572,6 +1572,32 @@ tdefault_augmented_libraries_svr4_read (struct target_ops *self)
   return 0;
 }
 
+static const struct frame_unwind *
+delegate_get_unwinder (struct target_ops *self)
+{
+  self = self->beneath;
+  return self->to_get_unwinder (self);
+}
+
+static const struct frame_unwind *
+tdefault_get_unwinder (struct target_ops *self)
+{
+  return NULL;
+}
+
+static const struct frame_unwind *
+delegate_get_tailcall_unwinder (struct target_ops *self)
+{
+  self = self->beneath;
+  return self->to_get_tailcall_unwinder (self);
+}
+
+static const struct frame_unwind *
+tdefault_get_tailcall_unwinder (struct target_ops *self)
+{
+  return NULL;
+}
+
 static CORE_ADDR
 delegate_decr_pc_after_break (struct target_ops *self, struct gdbarch *arg1)
 {
@@ -1844,6 +1870,10 @@ install_delegators (struct target_ops *ops)
     ops->to_call_history_range = delegate_call_history_range;
   if (ops->to_augmented_libraries_svr4_read == NULL)
     ops->to_augmented_libraries_svr4_read = delegate_augmented_libraries_svr4_read;
+  if (ops->to_get_unwinder == NULL)
+    ops->to_get_unwinder = delegate_get_unwinder;
+  if (ops->to_get_tailcall_unwinder == NULL)
+    ops->to_get_tailcall_unwinder = delegate_get_tailcall_unwinder;
   if (ops->to_decr_pc_after_break == NULL)
     ops->to_decr_pc_after_break = delegate_decr_pc_after_break;
 }
@@ -1982,5 +2012,7 @@ install_dummy_methods (struct target_ops *ops)
   ops->to_call_history_from = tdefault_call_history_from;
   ops->to_call_history_range = tdefault_call_history_range;
   ops->to_augmented_libraries_svr4_read = tdefault_augmented_libraries_svr4_read;
+  ops->to_get_unwinder = tdefault_get_unwinder;
+  ops->to_get_tailcall_unwinder = tdefault_get_tailcall_unwinder;
   ops->to_decr_pc_after_break = default_target_decr_pc_after_break;
 }
diff --git a/gdb/target.c b/gdb/target.c
index 72d5a09..d03c4fb 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3761,13 +3761,7 @@ debug_to_prepare_to_store (struct target_ops *self, struct regcache *regcache)
 const struct frame_unwind *
 target_get_unwinder (void)
 {
-  struct target_ops *t;
-
-  for (t = current_target.beneath; t != NULL; t = t->beneath)
-    if (t->to_get_unwinder != NULL)
-      return t->to_get_unwinder;
-
-  return NULL;
+  return current_target.to_get_unwinder (&current_target);
 }
 
 /* See target.h.  */
@@ -3775,13 +3769,7 @@ target_get_unwinder (void)
 const struct frame_unwind *
 target_get_tailcall_unwinder (void)
 {
-  struct target_ops *t;
-
-  for (t = current_target.beneath; t != NULL; t = t->beneath)
-    if (t->to_get_tailcall_unwinder != NULL)
-      return t->to_get_tailcall_unwinder;
-
-  return NULL;
+  return current_target.to_get_tailcall_unwinder (&current_target);
 }
 
 /* Default implementation of to_decr_pc_after_break.  */
diff --git a/gdb/target.h b/gdb/target.h
index c988a01..58519b0 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -1095,10 +1095,14 @@ struct target_ops
     int (*to_augmented_libraries_svr4_read) (struct target_ops *)
       TARGET_DEFAULT_RETURN (0);
 
-    /* Those unwinders are tried before any other arch unwinders.  Use NULL if
-       it is not used.  */
-    const struct frame_unwind *to_get_unwinder;
-    const struct frame_unwind *to_get_tailcall_unwinder;
+    /* Those unwinders are tried before any other arch unwinders.  If
+       SELF doesn't have unwinders, it should delegate to the
+       "beneath" target.  */
+    const struct frame_unwind *(*to_get_unwinder) (struct target_ops *self)
+      TARGET_DEFAULT_RETURN (NULL);
+
+    const struct frame_unwind *(*to_get_tailcall_unwinder) (struct target_ops *self)
+      TARGET_DEFAULT_RETURN (NULL);
 
     /* Return the number of bytes by which the PC needs to be decremented
        after executing a breakpoint instruction.
-- 
1.8.1.4