[patch v9 23/23] btrace, remote: drop qbtrace packet

[Markus Metzger <markus dot t dot metzger at intel dot com>]

Use the qXfer:btrace:read packet's annex to encode a trace read method:

  all ... read all trace
  new ... read all trace if the trace has changed

This obsoletes the need for the qbtrace packet.

CC: Pedro Alves <palves@redhat.com>
CC: Jan Kratochvil <jan.kratochvil@redhat.com>
CC: Eli Zaretskii <eliz@gnu.org>

2013-03-04  Markus Metzger  <markus.t.metzger@intel.com>

	* target.h (target_ops) <to_read_btrace>: Add type parameter.
	(target_ops) <to_btrace_has_changed>: Remove.
	(target_btrace_has_changed): Remove.
	(target_read_btrace): Add type parameter.
	* target.c (target_read_btrace): Add type parameter.
	(target_btrace_has_changed): Remove.
	* remote.c (PACKET_qbtrace): Remove.
	(remote_protocol_features): Remove qbtrace.
	(remote_supports_btrace): Remove check for qbtrace.
	(remote_btrace_has_changed): Remove.
	(remote_read_btrace): Consider read type.
	(init_remote_ops): Remove to_disable_btrace.
	(_initialize_remote): Remove qbtrace.
	* i386-linux-nat.c (_initialize_i386_linux_nat): Remove
	initialization of to_btrace_has_changed.
	* common/linux-btrace.h (linux_read_btrace): Add type parameter.
	(linux_btrace_has_changed): Removed.
	* common/linux-btrace.c (linux_btrace_has_changed): Moved.
	Changed to static.
	(linux_read_btrace): Consider read type.
	* common/btrace-common.h (btrace_read_type): New enum.
	* btrace.c (btrace_fetch): Only update branch trace if it
	changed.
	* amd64-linux-nat.c (_initialize_amd64_linux_nat): Remove
	initialization of to_btrace_has_changed.

gdbserver/

	* target.h (target_ops): Remove btrace_has_changed. Add type
	parameter to read_btrace. Update target_ macros.
	* server.c: Include btrace-common.h.
	(handle_qxfer_btrace): Consider read type in annex.
	(handle_btrace_query): Removed.
	(handle_query): Remove qbtrace from qSupported. Remove call to
	handle_btrace_query.
	* linux-low.c (linux_low_read_btrace): Consider read type.
	(linux_target_ops): Remove linux_btrace_has_changed.

doc/

	* gdb.texinfo (Remote Configuration): Remove qbtrace.
	Describe annex of Qbtrace.


---
 gdb/amd64-linux-nat.c      |    1 -
 gdb/btrace.c               |    6 ++-
 gdb/common/btrace-common.h |   11 +++++++
 gdb/common/linux-btrace.c  |   37 ++++++++++------------
 gdb/common/linux-btrace.h  |    6 +--
 gdb/doc/gdb.texinfo        |   32 ++++++--------------
 gdb/gdbserver/linux-low.c  |    6 ++--
 gdb/gdbserver/server.c     |   56 +++++++++--------------------------
 gdb/gdbserver/target.h     |   14 +++-----
 gdb/i386-linux-nat.c       |    1 -
 gdb/remote.c               |   70 ++++++++++---------------------------------
 gdb/target.c               |   19 ++----------
 gdb/target.h               |   12 ++-----
 13 files changed, 90 insertions(+), 181 deletions(-)

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index c82edda..6f13fca 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -1196,7 +1196,6 @@ _initialize_amd64_linux_nat (void)
   t->to_supports_btrace = linux_supports_btrace;
   t->to_enable_btrace = amd64_linux_enable_btrace;
   t->to_disable_btrace = amd64_linux_disable_btrace;
-  t->to_btrace_has_changed = linux_btrace_has_changed;
   t->to_read_btrace = linux_read_btrace;
 
   /* Register the target.  */
diff --git a/gdb/btrace.c b/gdb/btrace.c
index 406508d..2fe6bf5 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -413,6 +413,7 @@ void
 btrace_fetch (struct thread_info *tp)
 {
   struct btrace_thread_info *btinfo;
+  VEC (btrace_block_s) *btrace;
 
   DEBUG ("fetch thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
 
@@ -420,12 +421,13 @@ btrace_fetch (struct thread_info *tp)
   if (btinfo->target == NULL)
     return;
 
-  if (!target_btrace_has_changed (btinfo->target))
+  btrace = target_read_btrace (btinfo->target, btrace_read_new);
+  if (VEC_empty (btrace_block_s, btrace))
     return;
 
   btrace_clear (tp);
 
-  btinfo->btrace = target_read_btrace (btinfo->target);
+  btinfo->btrace = btrace;
   btinfo->itrace = compute_itrace (btinfo->btrace);
   btinfo->ftrace = compute_ftrace (btinfo->itrace);
 
diff --git a/gdb/common/btrace-common.h b/gdb/common/btrace-common.h
index 90372ba..eab6c74 100644
--- a/gdb/common/btrace-common.h
+++ b/gdb/common/btrace-common.h
@@ -59,4 +59,15 @@ DEF_VEC_O (btrace_block_s);
 /* Target specific branch trace information.  */
 struct btrace_target_info;
 
+/* Enumeration of btrace read types.  */
+
+enum btrace_read_type
+{
+  /* Send all available trace.  */
+  btrace_read_all,
+
+  /* Send all available trace, if it changed.  */
+  btrace_read_new
+};
+
 #endif /* BTRACE_COMMON_H */
diff --git a/gdb/common/linux-btrace.c b/gdb/common/linux-btrace.c
index 238d7ba..08a34dd 100644
--- a/gdb/common/linux-btrace.c
+++ b/gdb/common/linux-btrace.c
@@ -448,16 +448,6 @@ linux_supports_btrace (void)
 
 /* See linux-btrace.h.  */
 
-int
-linux_btrace_has_changed (struct btrace_target_info *tinfo)
-{
-  volatile struct perf_event_mmap_page *header = perf_event_header (tinfo);
-
-  return header->data_head != tinfo->data_head;
-}
-
-/* See linux-btrace.h.  */
-
 struct btrace_target_info *
 linux_enable_btrace (ptid_t ptid)
 {
@@ -526,10 +516,21 @@ linux_disable_btrace (struct btrace_target_info *tinfo)
   return 0;
 }
 
+/* Check whether the branch trace has changed.  */
+
+static int
+linux_btrace_has_changed (struct btrace_target_info *tinfo)
+{
+  volatile struct perf_event_mmap_page *header = perf_event_header (tinfo);
+
+  return header->data_head != tinfo->data_head;
+}
+
 /* See linux-btrace.h.  */
 
 VEC (btrace_block_s) *
-linux_read_btrace (struct btrace_target_info *tinfo)
+linux_read_btrace (struct btrace_target_info *tinfo,
+		   enum btrace_read_type type)
 {
   VEC (btrace_block_s) *btrace = NULL;
   volatile struct perf_event_mmap_page *header;
@@ -537,6 +538,9 @@ linux_read_btrace (struct btrace_target_info *tinfo)
   unsigned long data_head, retries = 5;
   size_t buffer_size;
 
+  if (type == btrace_read_new && !linux_btrace_has_changed (tinfo))
+    return NULL;
+
   header = perf_event_header (tinfo);
   buffer_size = perf_event_buffer_size (tinfo);
 
@@ -589,14 +593,6 @@ linux_supports_btrace (void)
 
 /* See linux-btrace.h.  */
 
-int
-linux_btrace_has_changed (struct btrace_target_info *tinfo)
-{
-  return 0;
-}
-
-/* See linux-btrace.h.  */
-
 struct btrace_target_info *
 linux_enable_btrace (ptid_t ptid)
 {
@@ -614,7 +610,8 @@ linux_disable_btrace (struct btrace_target_info *tinfo)
 /* See linux-btrace.h.  */
 
 VEC (btrace_block_s) *
-linux_read_btrace (struct btrace_target_info *tinfo)
+linux_read_btrace (struct btrace_target_info *tinfo,
+		   enum btrace_read_type type)
 {
   return NULL;
 }
diff --git a/gdb/common/linux-btrace.h b/gdb/common/linux-btrace.h
index b382e49..df4a4ae 100644
--- a/gdb/common/linux-btrace.h
+++ b/gdb/common/linux-btrace.h
@@ -70,10 +70,8 @@ extern struct btrace_target_info *linux_enable_btrace (ptid_t ptid);
 /* Disable branch tracing and deallocate @tinfo.  */
 extern int linux_disable_btrace (struct btrace_target_info *tinfo);
 
-/* Check whether there is new trace data available.  */
-extern int linux_btrace_has_changed (struct btrace_target_info *);
-
 /* Read branch trace data.  */
-extern VEC (btrace_block_s) *linux_read_btrace (struct btrace_target_info *);
+extern VEC (btrace_block_s) *linux_read_btrace (struct btrace_target_info *,
+						enum btrace_read_type);
 
 #endif /* LINUX_BTRACE_H */
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a3ebcd2..e8c2b34 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -37393,11 +37393,6 @@ These are the currently defined stub features and their properties:
 @tab @samp{-}
 @tab No
 
-@item @samp{qbtrace}
-@tab No
-@tab @samp{-}
-@tab Yes
-
 @item @samp{qXfer:auxv:read}
 @tab No
 @tab @samp{-}
@@ -37711,9 +37706,6 @@ See @ref{Bytecode Descriptions} for details about the bytecode.
 The remote stub supports running a breakpoint's command list itself,
 rather than reporting the hit to @value{GDBN}.
 
-@item qbtrace
-The remote stub understands the @samp{qbtrace} packet.
-
 @item Qbtrace:off
 The remote stub understands the @samp{Qbtrace:off} packet.
 
@@ -37843,7 +37835,16 @@ by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
 
 Return a description of the current branch trace.
 @xref{Branch Trace Format}.  The annex part of the generic @samp{qXfer}
-packet is empty.
+packet may have one of the following values:
+
+@table @code
+@item all
+Returns all available branch trace.
+
+@item new
+Returns all available branch trace if the branch trace changed since
+the last read request.
+@end table
 
 This packet is not probed by default; the remote stub must request it
 by supplying an appropriate @samp{qSupported} response (@pxref{qSupported}).
@@ -38084,19 +38085,6 @@ The remote server created a new process.
 A badly formed request or an error was encountered.
 @end table
 
-@item qbtrace
-Return whether new branch trace data is available for the current thread.
-
-Reply:
-@table @samp
-@item yes
-New branch trace data is available.
-@item no
-No new branch trace data is available.
-@item E.errtext
-A badly formed request or an error was encountered.
-@end table
-
 @item Qbtrace:bts
 Enable branch tracing for the current thread using bts tracing.
 
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index c4507c8..0131de6 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -5838,13 +5838,14 @@ linux_low_enable_btrace (ptid_t ptid)
 /* Read branch trace data as btrace xml document.  */
 
 static void
-linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer)
+linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer,
+		       int type)
 {
   VEC (btrace_block_s) *btrace;
   struct btrace_block *block;
   int i;
 
-  btrace = linux_read_btrace (tinfo);
+  btrace = linux_read_btrace (tinfo, type);
 
   buffer_grow_str (buffer, "<!DOCTYPE btrace SYSTEM \"btrace.dtd\">\n");
   buffer_grow_str (buffer, "<btrace version=\"1.0\">\n");
@@ -5927,7 +5928,6 @@ static struct target_ops linux_target_ops = {
   linux_supports_btrace,
   linux_low_enable_btrace,
   linux_disable_btrace,
-  linux_btrace_has_changed,
   linux_low_read_btrace,
 #else
   NULL,
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 00cac8e..6c8bff4 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -28,6 +28,7 @@
 #include <signal.h>
 #endif
 #include "gdb_wait.h"
+#include "btrace-common.h"
 
 /* The thread set with an `Hc' packet.  `Hc' is deprecated in favor of
    `vCont'.  Note the multi-process extensions made `vCont' a
@@ -1345,11 +1346,12 @@ handle_qxfer_btrace (const char *annex,
 {
   static struct buffer cache;
   struct thread_info *thread;
+  int type;
 
   if (the_target->read_btrace == NULL || writebuf != NULL)
     return -2;
 
-  if (!target_running () || annex[0] != '\0')
+  if (!target_running ())
     return -1;
 
   if (ptid_equal (general_thread, null_ptid)
@@ -1372,11 +1374,21 @@ handle_qxfer_btrace (const char *annex,
       return -1;
     }
 
+  if (strcmp (annex, "all") == 0)
+    type = btrace_read_all;
+  else if (strcmp (annex, "new") == 0)
+    type = btrace_read_new;
+  else
+    {
+      strcpy (own_buf, "E.Bad annex.");
+      return -1;
+    }
+
   if (offset == 0)
     {
       buffer_free (&cache);
 
-      target_read_btrace (thread->btrace, &cache);
+      target_read_btrace (thread->btrace, &cache, type);
     }
   else if (offset > cache.used_size)
     {
@@ -1560,42 +1572,6 @@ crc32 (CORE_ADDR base, int len, unsigned int crc)
   return (unsigned long long) crc;
 }
 
-/* Handle the "qbtrace" packet.  */
-
-static int
-handle_btrace_query (char *own_buf)
-{
-  if (strncmp ("qbtrace", own_buf, strlen ("qbtrace")) == 0)
-    {
-      struct thread_info *thread;
-
-      if (ptid_equal (general_thread, null_ptid)
-	  || ptid_equal (general_thread, minus_one_ptid))
-	{
-	  strcpy (own_buf, "E.Must select a single thread.");
-	  return -1;
-	}
-
-      thread = find_thread_ptid (general_thread);
-      if (thread == NULL)
-	{
-	  strcpy (own_buf, "E.No such thread.");
-	  return -1;
-	}
-
-      if (thread->btrace == NULL)
-	{
-	  strcpy (own_buf, "E.Btrace not enabled.");
-	  return -1;
-	}
-
-      strcpy (own_buf,
-	      (target_btrace_has_changed (thread->btrace) ? "yes" : "no"));
-      return 1;
-    }
-  return 0;
-}
-
 /* Handle all of the extended 'q' packets.  */
 
 void
@@ -1827,7 +1803,6 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
 
       if (target_supports_btrace ())
 	{
-	  strcat (own_buf, ";qbtrace+");
 	  strcat (own_buf, ";Qbtrace:bts+");
 	  strcat (own_buf, ";Qbtrace:off+");
 	  strcat (own_buf, ";qXfer:btrace:read+");
@@ -2023,9 +1998,6 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
   if (target_supports_tracepoints () && handle_tracepoint_query (own_buf))
     return;
 
-  if (handle_btrace_query (own_buf))
-    return;
-
   /* Otherwise we didn't know what packet it was.  Say we didn't
      understand it.  */
   own_buf[0] = 0;
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index a597911..f257459 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -410,11 +410,10 @@ struct target_ops
   /* Disable branch tracing.  */
   int (*disable_btrace) (struct btrace_target_info *tinfo);
 
-  /* Check whether branch trace changed on the target.  */
-  int (*btrace_has_changed) (struct btrace_target_info *);
+  /* Read branch trace data into buffer.  We use an int to specify the type
+     to break a cyclic dependency.  */
+  void (*read_btrace) (struct btrace_target_info *, struct buffer *, int type);
 
-  /* Read branch trace data into buffer.  */
-  void (*read_btrace) (struct btrace_target_info *, struct buffer *);
 };
 
 extern struct target_ops *the_target;
@@ -547,11 +546,8 @@ int kill_inferior (int);
 #define target_disable_btrace(tinfo) \
   (*the_target->disable_btrace) (tinfo)
 
-#define target_btrace_has_changed(tinfo) \
-  (*the_target->btrace_has_changed) (tinfo)
-
-#define target_read_btrace(tinfo, buffer) \
-  (*the_target->read_btrace) (tinfo, buffer)
+#define target_read_btrace(tinfo, buffer, type)	\
+  (*the_target->read_btrace) (tinfo, buffer, type)
 
 /* Start non-stop mode, returns 0 on success, -1 on failure.   */
 
diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c
index d439133..715c6d4 100644
--- a/gdb/i386-linux-nat.c
+++ b/gdb/i386-linux-nat.c
@@ -1118,7 +1118,6 @@ _initialize_i386_linux_nat (void)
   t->to_supports_btrace = linux_supports_btrace;
   t->to_enable_btrace = i386_linux_enable_btrace;
   t->to_disable_btrace = i386_linux_disable_btrace;
-  t->to_btrace_has_changed = linux_btrace_has_changed;
   t->to_read_btrace = linux_read_btrace;
 
   /* Register the target.  */
diff --git a/gdb/remote.c b/gdb/remote.c
index 2365713..f76846a 100755
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -1285,7 +1285,6 @@ enum {
   PACKET_qXfer_fdpic,
   PACKET_QDisableRandomization,
   PACKET_QAgent,
-  PACKET_qbtrace,
   PACKET_Qbtrace_off,
   PACKET_Qbtrace_bts,
   PACKET_qXfer_btrace,
@@ -4000,7 +3999,6 @@ static struct protocol_feature remote_protocol_features[] = {
   { "QAgent", PACKET_DISABLE, remote_supported_packet, PACKET_QAgent},
   { "tracenz", PACKET_DISABLE,
     remote_string_tracing_feature, -1 },
-  { "qbtrace", PACKET_DISABLE, remote_supported_packet, PACKET_qbtrace },
   { "Qbtrace:off", PACKET_DISABLE, remote_supported_packet, PACKET_Qbtrace_off },
   { "Qbtrace:bts", PACKET_DISABLE, remote_supported_packet, PACKET_Qbtrace_bts },
   { "qXfer:btrace:read", PACKET_DISABLE, remote_supported_packet,
@@ -11140,8 +11138,6 @@ struct btrace_target_info
 static int
 remote_supports_btrace (void)
 {
-  if (remote_protocol_packets[PACKET_qbtrace].support != PACKET_ENABLE)
-    return 0;
   if (remote_protocol_packets[PACKET_Qbtrace_off].support != PACKET_ENABLE)
     return 0;
   if (remote_protocol_packets[PACKET_Qbtrace_bts].support != PACKET_ENABLE)
@@ -11208,57 +11204,16 @@ remote_disable_btrace (struct btrace_target_info *tinfo)
   xfree (tinfo);
 }
 
-/* Check whether branch trace data has changed.  */
-
-static int
-remote_btrace_has_changed (struct btrace_target_info *tinfo)
-{
-  struct packet_config *packet = &remote_protocol_packets[PACKET_qbtrace];
-  struct remote_state *rs = get_remote_state ();
-  char *buf = rs->buf;
-  char *endbuf = rs->buf + get_remote_packet_size ();
-
-  if (packet->support != PACKET_ENABLE)
-    error (_("Target does not support branch tracing."));
-
-  set_general_thread (tinfo->ptid);
-
-  buf += xsnprintf (buf, endbuf - buf, "%s", packet->name);
-  putpkt (rs->buf);
-  getpkt (&rs->buf, &rs->buf_size, 0);
-
-  switch (packet_ok (rs->buf, packet))
-    {
-    case PACKET_OK:
-      break;
-
-    case PACKET_UNKNOWN:
-      return 0;
-
-    case PACKET_ERROR:
-      error (_("Failed to check for branch trace data for %s: %s."),
-             target_pid_to_str (tinfo->ptid), rs->buf);
-    }
-
-  if (strcmp (rs->buf, "yes") == 0)
-    return 1;
-
-  if (strcmp (rs->buf, "no") == 0)
-    return 0;
-
-  error (_("Bad remote reply: %s."), rs->buf);
-
-  return 0;
-}
-
 /* Read the branch trace.  */
 
 static VEC (btrace_block_s) *
-remote_read_btrace (struct btrace_target_info *tinfo)
+remote_read_btrace (struct btrace_target_info *tinfo,
+		    enum btrace_read_type type)
 {
   struct packet_config *packet = &remote_protocol_packets[PACKET_qXfer_btrace];
   struct remote_state *rs = get_remote_state ();
   VEC (btrace_block_s) *btrace = NULL;
+  const char *annex;
   char *xml;
 
   if (packet->support != PACKET_ENABLE)
@@ -11268,8 +11223,21 @@ remote_read_btrace (struct btrace_target_info *tinfo)
   error (_("Cannot process branch tracing result. XML parsing not supported."));
 #endif
 
+  switch (type)
+    {
+    case btrace_read_all:
+      annex = "all";
+      break;
+    case btrace_read_new:
+      annex = "new";
+      break;
+    default:
+      annex = NULL;
+      break;
+    }
+
   xml = target_read_stralloc (&current_target,
-                              TARGET_OBJECT_BTRACE, NULL);
+                              TARGET_OBJECT_BTRACE, annex);
   if (xml != NULL)
     {
       struct cleanup *cleanup = make_cleanup (xfree, xml);
@@ -11400,7 +11368,6 @@ Specify the serial device it is connected to\n\
   remote_ops.to_supports_btrace = remote_supports_btrace;
   remote_ops.to_enable_btrace = remote_enable_btrace;
   remote_ops.to_disable_btrace = remote_disable_btrace;
-  remote_ops.to_btrace_has_changed = remote_btrace_has_changed;
   remote_ops.to_read_btrace = remote_read_btrace;
 }
 
@@ -11926,9 +11893,6 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
   add_packet_config_cmd (&remote_protocol_packets[PACKET_QAgent],
 			 "QAgent", "agent", 0);
 
-  add_packet_config_cmd (&remote_protocol_packets[PACKET_qbtrace],
-       "qbtrace", "query-btrace", 0);
-
   add_packet_config_cmd (&remote_protocol_packets[PACKET_Qbtrace_off],
        "Qbtrace:off", "disable-btrace", 0);
 
diff --git a/gdb/target.c b/gdb/target.c
index a788a67..778b6b9 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -4203,28 +4203,15 @@ target_disable_btrace (struct btrace_target_info *btinfo)
 }
 
 /* See target.h.  */
-int
-target_btrace_has_changed (struct btrace_target_info *btinfo)
-{
-  struct target_ops *t;
-
-  for (t = current_target.beneath; t != NULL; t = t->beneath)
-    if (t->to_btrace_has_changed != NULL)
-      return t->to_btrace_has_changed (btinfo);
-
-  tcomplain ();
-  return 0;
-}
-
-/* See target.h.  */
 VEC (btrace_block_s) *
-target_read_btrace (struct btrace_target_info *btinfo)
+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);
+      return t->to_read_btrace (btinfo, type);
 
   tcomplain ();
   return NULL;
diff --git a/gdb/target.h b/gdb/target.h
index a3fd892..88c13cc 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -870,11 +870,9 @@ struct target_ops
     /* Disable branch tracing and deallocate @tinfo.  */
     void (*to_disable_btrace) (struct btrace_target_info *tinfo);
 
-    /* Check whether branch trace changed on the target.  */
-    int (*to_btrace_has_changed) (struct btrace_target_info *);
-
     /* Read branch trace data.  */
-    VEC (btrace_block_s) *(*to_read_btrace) (struct btrace_target_info *);
+    VEC (btrace_block_s) *(*to_read_btrace) (struct btrace_target_info *,
+					     enum btrace_read_type);
 
     /* Print information about the recording.  */
     void (*to_info_record) (void);
@@ -1973,12 +1971,10 @@ extern struct btrace_target_info *target_enable_btrace (ptid_t ptid);
 /* Disable branch tracing. Deallocates @btinfo.  */
 extern void target_disable_btrace (struct btrace_target_info *btinfo);
 
-/* Check whether there is no branch tracing data available.  */
-extern int target_btrace_has_changed (struct btrace_target_info *btinfo);
-
 /* Read branch tracing data.
    Returns a vector of branch trace blocks with the latest entry at index 0.  */
-extern VEC (btrace_block_s) *target_read_btrace (struct btrace_target_info *);
+extern VEC (btrace_block_s) *target_read_btrace (struct btrace_target_info *,
+						 enum btrace_read_type);
 
 /* See to_info_record in struct target_ops.  */
 extern void target_info_record (void);
-- 
1.7.1