record btrace: add configuration struct

Add a struct to describe the branch trace configuration and use it for
enabling branch tracing.

The user will be able to set configuration fields for each tracing format
to be used for new threads.

The actual configuration that is active for a given thread will be shown
in the "info record" command.

At the moment, the configuration struct only contains a format field
that is set to the only available format.

The format is the only configuration option that can not be set via set
commands.  It is given as argument to the "record btrace" command when
starting recording.

2015-02-09  Markus Metzger  <markus.t.metzger@intel.com>

	* Makefile.in (XMLFILES): Add btrace-conf.dtd.
	* x86-linux-nat.c (x86_linux_enable_btrace): Update parameters.
	(x86_linux_btrace_conf): New.
	(x86_linux_create_target): Initialize to_btrace_conf.
	* nat/linux-btrace.c (linux_enable_btrace): Update parameters.
	Check format.  Split into this and ...
	(linux_enable_bts): ... this.
	(linux_btrace_conf): New.
	(perf_event_skip_record): Renamed into ...
	(perf_event_skip_bts_record): ... this.  Updated users.
	(linux_disable_btrace): Split into this and ...
	(linux_disable_bts): ... this.
	(linux_read_btrace): Check format.
	* nat/linux-btrace.h (linux_enable_btrace): Update parameters.
	(linux_btrace_conf): New.
	(btrace_target_info)<ptid>: Moved.
	(btrace_target_info)<conf>: New.
	(btrace_target_info): Split into this and ...
	(btrace_tinfo_bts): ... this.  Updated users.
	* btrace.c (btrace_enable): Update parameters.
	(btrace_conf, parse_xml_btrace_conf_bts, parse_xml_btrace_conf)
	(btrace_conf_children, btrace_conf_attributes)
	(btrace_conf_elements): New.
	* btrace.h (btrace_enable): Update parameters.
	(btrace_conf, parse_xml_btrace_conf): New.
	* common/btrace-common.h (btrace_config): New.
	* feature/btrace-conf.dtd: New.
	* record-btrace.c (record_btrace_conf): New.
	(record_btrace_cmdlist): New.
	(record_btrace_enable_warn, record_btrace_open): Pass
	&record_btrace_conf.
	(record_btrace_info): Print recording format.
	(cmd_record_btrace_bts_start): New.
	(cmd_record_btrace_start): Call cmd_record_btrace_bts_start.
	(_initialize_record_btrace): Add "record btrace bts" subcommand.
	Add "record bts" alias command.
	* remote.c (remote_state)<btrace_config>: New.
	(remote_btrace_reset, PACKET_qXfer_btrace_conf): New.
	(remote_protocol_features): Add qXfer:btrace-conf:read.
	(remote_open_1): Call remote_btrace_reset.
	(remote_xfer_partial): Handle TARGET_OBJECT_BTRACE_CONF.
	(btrace_target_info)<conf>: New.
	(btrace_sync_conf, btrace_read_config): New.
	(remote_enable_btrace): Update parameters.  Call btrace_sync_conf and
	btrace_read_conf.
	(remote_btrace_conf): New.
	(init_remote_ops): Initialize to_btrace_conf.
	(_initialize_remote): Add qXfer:btrace-conf packet.
	* target.c (target_enable_btrace): Update parameters.
	(target_btrace_conf): New.
	* target.h (target_enable_btrace): Update parameters.
	(target_btrace_conf): New.
	(target_object)<TARGET_OBJECT_BTRACE_CONF>: New.
	(target_ops)<to_enable_btrace>: Update parameters and comment.
	(target_ops)<to_btrace_conf>: New.
	* target-delegates: Regenerate.
	* target-debug.h (target_debug_print_const_struct_btrace_config_p)
	(target_debug_print_const_struct_btrace_target_info_p): New.
	NEWS: Announce new command and new packet.

doc/
	* gdb.texinfo (Process Record and Replay): Describe the "record
	btrace bts" command.
	(General Query Packets): Describe qXfer:btrace-conf:read packet.
	(Branch Trace Configuration Format): New.

gdbserver/
	* linux-low.c (linux_low_enable_btrace): Update parameters.
	(linux_low_btrace_conf): New.
	(linux_target_ops)<to_btrace_conf>: Initialize.
	* server.c (current_btrace_conf): New.
	(handle_btrace_enable): Rename to ...
	(handle_btrace_enable_bts): ... this.  Pass &current_btrace_conf
	to target_enable_btrace.  Update comment.  Update users.
	(handle_qxfer_btrace_conf): New.
    (qxfer_packets): Add btrace-conf entry.
	(handle_query): Report qXfer:btrace-conf:read as supported packet.
	* target.h (target_ops)<enable_btrace>: Update parameters and comment.
	(target_ops)<read_btrace_conf>: New.
	(target_enable_btrace): Update parameters.
	(target_read_btrace_conf): New.

testsuite/
	* gdb.btrace/delta.exp: Update "info record" output.
	* gdb.btrace/enable.exp: Update "info record" output.
	* gdb.btrace/finish.exp: Update "info record" output.
	* gdb.btrace/instruction_history.exp: Update "info record" output.
	* gdb.btrace/next.exp: Update "info record" output.
	* gdb.btrace/nexti.exp: Update "info record" output.
	* gdb.btrace/step.exp: Update "info record" output.
	* gdb.btrace/stepi.exp: Update "info record" output.
	* gdb.btrace/nohist.exp: Update "info record" output.

1 files changed, 83 insertions, 2 deletions

diff --git a/gdb/remote.c b/gdb/remote.c
index 61420ec..0226f3f 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -221,6 +221,8 @@ static int remote_supports_cond_breakpoints (struct target_ops *self);
 
 static int remote_can_run_breakpoint_commands (struct target_ops *self);
 
+static void remote_btrace_reset (void);
+
 /* For "remote".  */
 
 static struct cmd_list_element *remote_cmdlist;
@@ -371,6 +373,9 @@ struct remote_state
 
   /* The state of remote notification.  */
   struct remote_notif_state *notif_state;
+
+  /* The branch trace configuration.  */
+  struct btrace_config btrace_config;
 };
 
 /* Private data that we'll store in (struct thread_info)->private.  */
@@ -1327,6 +1332,9 @@ enum {
   /* Support for qXfer:libraries-svr4:read with a non-empty annex.  */
   PACKET_augmented_libraries_svr4_read_feature,
 
+  /* Support for the qXfer:btrace-conf:read packet.  */
+  PACKET_qXfer_btrace_conf,
+
   PACKET_MAX
 };
 
@@ -4010,7 +4018,9 @@ static const struct protocol_feature remote_protocol_features[] = {
   { "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,
-    PACKET_qXfer_btrace }
+    PACKET_qXfer_btrace },
+  { "qXfer:btrace-conf:read", PACKET_DISABLE, remote_supported_packet,
+    PACKET_qXfer_btrace_conf }
 };
 
 static char *remote_support_xml;
@@ -4358,6 +4368,8 @@ remote_open_1 (const char *name, int from_tty,
       }
   }
 
+  remote_btrace_reset ();
+
   if (target_async_permitted)
     wait_forever_enabled_p = 1;
 }
@@ -8945,6 +8957,11 @@ remote_xfer_partial (struct target_ops *ops, enum target_object object,
 				xfered_len,
         &remote_protocol_packets[PACKET_qXfer_btrace]);
 
+    case TARGET_OBJECT_BTRACE_CONF:
+      return remote_read_qxfer (ops, "btrace-conf", annex, readbuf, offset,
+				len, xfered_len,
+	&remote_protocol_packets[PACKET_qXfer_btrace_conf]);
+
     default:
       return TARGET_XFER_E_IO;
     }
@@ -11319,8 +11336,21 @@ struct btrace_target_info
 {
   /* The ptid of the traced thread.  */
   ptid_t ptid;
+
+  /* The obtained branch trace configuration.  */
+  struct btrace_config conf;
 };
 
+/* Reset our idea of our target's btrace configuration.  */
+
+static void
+remote_btrace_reset (void)
+{
+  struct remote_state *rs = get_remote_state ();
+
+  memset (&rs->btrace_config, 0, sizeof (rs->btrace_config));
+}
+
 /* Check whether the target supports branch tracing.  */
 
 static int
@@ -11343,20 +11373,52 @@ remote_supports_btrace (struct target_ops *self, enum btrace_format format)
   internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
 }
 
+/* Synchronize the configuration with the target.  */
+
+static void
+btrace_sync_conf (const struct btrace_config *conf)
+{
+  /* Nothing to do for now.  */
+}
+
+/* Read the current thread's btrace configuration from the target and
+   store it into CONF.  */
+
+static void
+btrace_read_config (struct btrace_config *conf)
+{
+  char *xml;
+
+  xml = target_read_stralloc (&current_target,
+                              TARGET_OBJECT_BTRACE_CONF, "");
+  if (xml != NULL)
+    {
+      struct cleanup *cleanup;
+
+      cleanup = make_cleanup (xfree, xml);
+      parse_xml_btrace_conf (conf, xml);
+      do_cleanups (cleanup);
+    }
+}
+
 /* Enable branch tracing.  */
 
 static struct btrace_target_info *
-remote_enable_btrace (struct target_ops *self, ptid_t ptid)
+remote_enable_btrace (struct target_ops *self, ptid_t ptid,
+		      const struct btrace_config *conf)
 {
   struct btrace_target_info *tinfo = NULL;
   struct packet_config *packet = &remote_protocol_packets[PACKET_Qbtrace_bts];
   struct remote_state *rs = get_remote_state ();
   char *buf = rs->buf;
   char *endbuf = rs->buf + get_remote_packet_size ();
+  volatile struct gdb_exception err;
 
   if (packet_config_support (packet) != PACKET_ENABLE)
     error (_("Target does not support branch tracing."));
 
+  btrace_sync_conf (conf);
+
   set_general_thread (ptid);
 
   buf += xsnprintf (buf, endbuf - buf, "%s", packet->name);
@@ -11376,6 +11438,14 @@ remote_enable_btrace (struct target_ops *self, ptid_t ptid)
   tinfo = xzalloc (sizeof (*tinfo));
   tinfo->ptid = ptid;
 
+  /* If we fail to read the configuration, we lose some information, but the
+     tracing itself is not impacted.  */
+  TRY_CATCH (err, RETURN_MASK_ERROR)
+    btrace_read_config (&tinfo->conf);
+
+  if (err.message != NULL)
+    warning ("%s", err.message);
+
   return tinfo;
 }
 
@@ -11472,6 +11542,13 @@ remote_read_btrace (struct target_ops *self,
   return BTRACE_ERR_NONE;
 }
 
+static const struct btrace_config *
+remote_btrace_conf (struct target_ops *self,
+		    const struct btrace_target_info *tinfo)
+{
+  return &tinfo->conf;
+}
+
 static int
 remote_augmented_libraries_svr4_read (struct target_ops *self)
 {
@@ -11608,6 +11685,7 @@ Specify the serial device it is connected to\n\
   remote_ops.to_disable_btrace = remote_disable_btrace;
   remote_ops.to_teardown_btrace = remote_teardown_btrace;
   remote_ops.to_read_btrace = remote_read_btrace;
+  remote_ops.to_btrace_conf = remote_btrace_conf;
   remote_ops.to_augmented_libraries_svr4_read =
     remote_augmented_libraries_svr4_read;
 }
@@ -12206,6 +12284,9 @@ Show the maximum size of the address (in bits) in a memory packet."), NULL,
   add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_btrace],
        "qXfer:btrace", "read-btrace", 0);
 
+  add_packet_config_cmd (&remote_protocol_packets[PACKET_qXfer_btrace_conf],
+       "qXfer:btrace-conf", "read-btrace-conf", 0);
+
   /* Assert that we've registered commands for all packet configs.  */
   {
     int i;