Add branch trace information to struct thread_info.

Add functions to enable, disable, clear, and fetch a thread's branch trace.

gdb/
	* target.h: Include btrace.h.
	(struct target_ops) <to_supports_btrace, to_enable_btrace,
	to_disable_btrace, to_teardown_btrace, to_read_btrace>: New.
	* target.c (target_supports_btrace): New function.
	(target_enable_btrace): New function.
	(target_disable_btrace): New function.
	(target_teardown_btrace): New function.
	(target_read_btrace): New function.
	* btrace.h: New file.
	* btrace.c: New file.
	* Makefile.in: Add btrace.c.
	* gdbthread.h: Include btrace.h.
	(struct thread_info): Add btrace field.
	* thread.c: Include btrace.h.
	(clear_thread_inferior_resources): Call target_teardown_btrace.
	* common/btrace-common.h: New file.

1 files changed, 73 insertions, 0 deletions

diff --git a/gdb/target.c b/gdb/target.c
index 0b4f39d45c4..524caec7122 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -4153,6 +4153,79 @@ target_ranged_break_num_registers (void)
   return -1;
 }
 
+/* See target.h.  */
+
+int
+target_supports_btrace (void)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_supports_btrace != NULL)
+      return t->to_supports_btrace ();
+
+  return 0;
+}
+
+/* See target.h.  */
+
+struct btrace_target_info *
+target_enable_btrace (ptid_t ptid)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_enable_btrace != NULL)
+      return t->to_enable_btrace (ptid);
+
+  tcomplain ();
+  return NULL;
+}
+
+/* See target.h.  */
+
+void
+target_disable_btrace (struct btrace_target_info *btinfo)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_disable_btrace != NULL)
+      return t->to_disable_btrace (btinfo);
+
+  tcomplain ();
+}
+
+/* See target.h.  */
+
+void
+target_teardown_btrace (struct btrace_target_info *btinfo)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_teardown_btrace != NULL)
+      return t->to_teardown_btrace (btinfo);
+
+  tcomplain ();
+}
+
+/* See target.h.  */
+
+VEC (btrace_block_s) *
+target_read_btrace (struct btrace_target_info *btinfo,
+		    enum btrace_read_type type)
+{
+  struct target_ops *t;
+
+  for (t = current_target.beneath; t != NULL; t = t->beneath)
+    if (t->to_read_btrace != NULL)
+      return t->to_read_btrace (btinfo, type);
+
+  tcomplain ();
+  return NULL;
+}
+
 static void
 debug_to_prepare_to_store (struct regcache *regcache)
 {