[PATCH v4 2/9] btrace: add format argument to supports_btrace

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

Add a format argument to the various supports_btrace functions to check
for support of a specific btrace format.  This is to prepare for a new
format.

Removed two redundant calls.  The check will be made in the subsequent
btrace_enable call.

2015-02-05  Markus Metzger <markus.t.metzger@intel.com>

	* btrace.c (btrace_enable): Pass BTRACE_FORMAT_BTS.
	* record-btrace.c (record_btrace_open): Remove call to
	target_supports_btrace.
	* remote.c (remote_supports_btrace): Update parameters.
	* target.c (target_supports_btrace): Update parameters.
	* target.h (to_supports_btrace, target_supports_btrace): Update
	parameters.
	* target-delegates.c: Regenerate.
	* target-debug.h (target_debug_print_enum_btrace_format): New.
	* nat/linux-btrace.c
	(kernel_supports_btrace): Rename into ...
	(kernel_supports_bts): ... this.  Update users.  Update warning text.
	(intel_supports_btrace): Rename into ...
	(intel_supports_bts): ... this.  Update users.
	(cpu_supports_btrace): Rename into ...
	(cpu_supports_bts): ... this.  Update users.
	(linux_supports_btrace): Update parameters.  Split into this and ...
	(linux_supports_bts): ... this.
	* nat/linux-btrace.h (linux_supports_btrace): Update parameters.

gdbserver/
	* server.c (handle_btrace_general_set): Remove call to
	target_supports_btrace.
	(supported_btrace_packets): New.
	(handle_query): Call supported_btrace_packets.
	* target.h: include btrace-common.h.
	(btrace_target_info): Removed.
	(supports_btrace, target_supports_btrace): Update parameters.
---
 gdb/btrace.c           |  2 +-
 gdb/gdbserver/server.c | 27 +++++++++++++-----------
 gdb/gdbserver/target.h |  8 +++----
 gdb/nat/linux-btrace.c | 57 ++++++++++++++++++++++++++++++++------------------
 gdb/nat/linux-btrace.h |  2 +-
 gdb/record-btrace.c    |  3 ---
 gdb/remote.c           | 15 +++++++++----
 gdb/target-debug.h     |  2 ++
 gdb/target-delegates.c | 12 ++++++-----
 gdb/target.c           |  8 +++++++
 gdb/target.h           |  5 ++---
 11 files changed, 88 insertions(+), 53 deletions(-)

diff --git a/gdb/btrace.c b/gdb/btrace.c
index 3b20981..4e32bdc 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -731,7 +731,7 @@ btrace_enable (struct thread_info *tp)
   if (tp->btrace.target != NULL)
     return;
 
-  if (!target_supports_btrace ())
+  if (!target_supports_btrace (BTRACE_FORMAT_BTS))
     error (_("Target does not support branch tracing."));
 
   DEBUG ("enable thread %d (%s)", tp->num, target_pid_to_str (tp->ptid));
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index 0e72cf1..1756a1f 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -426,12 +426,6 @@ handle_btrace_general_set (char *own_buf)
 
   op = own_buf + strlen ("Qbtrace:");
 
-  if (!target_supports_btrace ())
-    {
-      strcpy (own_buf, "E.Target does not support branch tracing.");
-      return -1;
-    }
-
   if (ptid_equal (general_thread, null_ptid)
       || ptid_equal (general_thread, minus_one_ptid))
     {
@@ -1692,6 +1686,20 @@ crc32 (CORE_ADDR base, int len, unsigned int crc)
   return (unsigned long long) crc;
 }
 
+/* Add supported btrace packets to BUF.  */
+
+static void
+supported_btrace_packets (char *buf)
+{
+  if (target_supports_btrace (BTRACE_FORMAT_BTS))
+    strcat (buf, ";Qbtrace:bts+");
+  else
+    return;
+
+  strcat (buf, ";Qbtrace:off+");
+  strcat (buf, ";qXfer:btrace:read+");
+}
+
 /* Handle all of the extended 'q' packets.  */
 
 void
@@ -1923,12 +1931,7 @@ handle_query (char *own_buf, int packet_len, int *new_packet_len_p)
       if (target_supports_agent ())
 	strcat (own_buf, ";QAgent+");
 
-      if (target_supports_btrace ())
-	{
-	  strcat (own_buf, ";Qbtrace:bts+");
-	  strcat (own_buf, ";Qbtrace:off+");
-	  strcat (own_buf, ";qXfer:btrace:read+");
-	}
+      supported_btrace_packets (own_buf);
 
       return;
     }
diff --git a/gdb/gdbserver/target.h b/gdb/gdbserver/target.h
index bbb0567..ed57886 100644
--- a/gdb/gdbserver/target.h
+++ b/gdb/gdbserver/target.h
@@ -26,9 +26,9 @@
 #include "target/wait.h"
 #include "target/waitstatus.h"
 #include "mem-break.h"
+#include "btrace-common.h"
 
 struct emit_ops;
-struct btrace_target_info;
 struct buffer;
 struct process_info;
 
@@ -355,7 +355,7 @@ struct target_ops
   int (*supports_agent) (void);
 
   /* Check whether the target supports branch tracing.  */
-  int (*supports_btrace) (struct target_ops *);
+  int (*supports_btrace) (struct target_ops *, enum btrace_format);
 
   /* Enable branch tracing for @ptid and allocate a branch trace target
      information struct for reading and for disabling branch trace.  */
@@ -489,9 +489,9 @@ int kill_inferior (int);
   (the_target->supports_agent ? \
    (*the_target->supports_agent) () : 0)
 
-#define target_supports_btrace()			\
+#define target_supports_btrace(format)			\
   (the_target->supports_btrace				\
-   ? (*the_target->supports_btrace) (the_target) : 0)
+   ? (*the_target->supports_btrace) (the_target, format) : 0)
 
 #define target_enable_btrace(ptid) \
   (*the_target->enable_btrace) (ptid)
diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index 6cec5d0..08eb49b 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -248,10 +248,10 @@ perf_event_read_bts (struct btrace_target_info* tinfo, const uint8_t *begin,
   return btrace;
 }
 
-/* Check whether the kernel supports branch tracing.  */
+/* Check whether the kernel supports BTS.  */
 
 static int
-kernel_supports_btrace (void)
+kernel_supports_bts (void)
 {
   struct perf_event_attr attr;
   pid_t child, pid;
@@ -262,14 +262,14 @@ kernel_supports_btrace (void)
   switch (child)
     {
     case -1:
-      warning (_("test branch tracing: cannot fork: %s."), strerror (errno));
+      warning (_("test bts: cannot fork: %s."), strerror (errno));
       return 0;
 
     case 0:
       status = ptrace (PTRACE_TRACEME, 0, NULL, NULL);
       if (status != 0)
 	{
-	  warning (_("test branch tracing: cannot PTRACE_TRACEME: %s."),
+	  warning (_("test bts: cannot PTRACE_TRACEME: %s."),
 		   strerror (errno));
 	  _exit (1);
 	}
@@ -277,7 +277,7 @@ kernel_supports_btrace (void)
       status = raise (SIGTRAP);
       if (status != 0)
 	{
-	  warning (_("test branch tracing: cannot raise SIGTRAP: %s."),
+	  warning (_("test bts: cannot raise SIGTRAP: %s."),
 		   strerror (errno));
 	  _exit (1);
 	}
@@ -288,14 +288,14 @@ kernel_supports_btrace (void)
       pid = waitpid (child, &status, 0);
       if (pid != child)
 	{
-	  warning (_("test branch tracing: bad pid %ld, error: %s."),
+	  warning (_("test bts: bad pid %ld, error: %s."),
 		   (long) pid, strerror (errno));
 	  return 0;
 	}
 
       if (!WIFSTOPPED (status))
 	{
-	  warning (_("test branch tracing: expected stop. status: %d."),
+	  warning (_("test bts: expected stop. status: %d."),
 		   status);
 	  return 0;
 	}
@@ -320,10 +320,10 @@ kernel_supports_btrace (void)
       pid = waitpid (child, &status, 0);
       if (pid != child)
 	{
-	  warning (_("test branch tracing: bad pid %ld, error: %s."),
+	  warning (_("test bts: bad pid %ld, error: %s."),
 		   (long) pid, strerror (errno));
 	  if (!WIFSIGNALED (status))
-	    warning (_("test branch tracing: expected killed. status: %d."),
+	    warning (_("test bts: expected killed. status: %d."),
 		     status);
 	}
 
@@ -331,10 +331,10 @@ kernel_supports_btrace (void)
     }
 }
 
-/* Check whether an Intel cpu supports branch tracing.  */
+/* Check whether an Intel cpu supports BTS.  */
 
 static int
-intel_supports_btrace (void)
+intel_supports_bts (void)
 {
   unsigned int cpuid, model, family;
 
@@ -372,10 +372,10 @@ intel_supports_btrace (void)
   return 1;
 }
 
-/* Check whether the cpu supports branch tracing.  */
+/* Check whether the cpu supports BTS.  */
 
 static int
-cpu_supports_btrace (void)
+cpu_supports_bts (void)
 {
   unsigned int ebx, ecx, edx;
 
@@ -384,24 +384,24 @@ cpu_supports_btrace (void)
 
   if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
       && edx == signature_INTEL_edx)
-    return intel_supports_btrace ();
+    return intel_supports_bts ();
 
   /* Don't know about others.  Let's assume they do.  */
   return 1;
 }
 
-/* See linux-btrace.h.  */
+/* Check whether the linux target supports BTS.  */
 
-int
-linux_supports_btrace (struct target_ops *ops)
+static int
+linux_supports_bts (void)
 {
   static int cached;
 
   if (cached == 0)
     {
-      if (!kernel_supports_btrace ())
+      if (!kernel_supports_bts ())
 	cached = -1;
-      else if (!cpu_supports_btrace ())
+      else if (!cpu_supports_bts ())
 	cached = -1;
       else
 	cached = 1;
@@ -412,6 +412,23 @@ linux_supports_btrace (struct target_ops *ops)
 
 /* See linux-btrace.h.  */
 
+int
+linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
+{
+  switch (format)
+    {
+    case BTRACE_FORMAT_NONE:
+      return 0;
+
+    case BTRACE_FORMAT_BTS:
+      return linux_supports_bts ();
+    }
+
+  internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
+}
+
+/* See linux-btrace.h.  */
+
 struct btrace_target_info *
 linux_enable_btrace (ptid_t ptid)
 {
@@ -602,7 +619,7 @@ linux_read_btrace (struct btrace_data *btrace,
 /* See linux-btrace.h.  */
 
 int
-linux_supports_btrace (struct target_ops *ops)
+linux_supports_btrace (struct target_ops *ops, enum btrace_format format)
 {
   return 0;
 }
diff --git a/gdb/nat/linux-btrace.h b/gdb/nat/linux-btrace.h
index 1b11aba..24e06e8 100644
--- a/gdb/nat/linux-btrace.h
+++ b/gdb/nat/linux-btrace.h
@@ -61,7 +61,7 @@ struct btrace_target_info
 };
 
 /* See to_supports_btrace in target.h.  */
-extern int linux_supports_btrace (struct target_ops *);
+extern int linux_supports_btrace (struct target_ops *, enum btrace_format);
 
 /* See to_enable_btrace in target.h.  */
 extern struct btrace_target_info *linux_enable_btrace (ptid_t ptid);
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 7af549f..99c6684 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -199,9 +199,6 @@ record_btrace_open (const char *args, int from_tty)
   if (!target_has_execution)
     error (_("The program is not being run."));
 
-  if (!target_supports_btrace ())
-    error (_("Target does not support branch tracing."));
-
   if (non_stop)
     error (_("Record btrace can't debug inferior in non-stop mode."));
 
diff --git a/gdb/remote.c b/gdb/remote.c
index e7557d7..61420ec 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -11324,16 +11324,23 @@ struct btrace_target_info
 /* Check whether the target supports branch tracing.  */
 
 static int
-remote_supports_btrace (struct target_ops *self)
+remote_supports_btrace (struct target_ops *self, enum btrace_format format)
 {
   if (packet_support (PACKET_Qbtrace_off) != PACKET_ENABLE)
     return 0;
-  if (packet_support (PACKET_Qbtrace_bts) != PACKET_ENABLE)
-    return 0;
   if (packet_support (PACKET_qXfer_btrace) != PACKET_ENABLE)
     return 0;
 
-  return 1;
+  switch (format)
+    {
+      case BTRACE_FORMAT_NONE:
+	return 0;
+
+      case BTRACE_FORMAT_BTS:
+	return (packet_support (PACKET_Qbtrace_bts) == PACKET_ENABLE);
+    }
+
+  internal_error (__FILE__, __LINE__, _("Unknown branch trace format"));
 }
 
 /* Enable branch tracing.  */
diff --git a/gdb/target-debug.h b/gdb/target-debug.h
index 8a32810..61cc3a5 100644
--- a/gdb/target-debug.h
+++ b/gdb/target-debug.h
@@ -146,6 +146,8 @@
   target_debug_do_print (host_address_to_string (X))
 #define target_debug_print_struct_btrace_data_p(X)	\
   target_debug_do_print (host_address_to_string (X))
+#define target_debug_print_enum_btrace_format(X)	\
+  target_debug_do_print (plongest (X))
 
 static void
 target_debug_print_struct_target_waitstatus_p (struct target_waitstatus *status)
diff --git a/gdb/target-delegates.c b/gdb/target-delegates.c
index 00956ba..9cdb31e 100644
--- a/gdb/target-delegates.c
+++ b/gdb/target-delegates.c
@@ -3085,26 +3085,28 @@ debug_can_use_agent (struct target_ops *self)
 }
 
 static int
-delegate_supports_btrace (struct target_ops *self)
+delegate_supports_btrace (struct target_ops *self, enum btrace_format arg1)
 {
   self = self->beneath;
-  return self->to_supports_btrace (self);
+  return self->to_supports_btrace (self, arg1);
 }
 
 static int
-tdefault_supports_btrace (struct target_ops *self)
+tdefault_supports_btrace (struct target_ops *self, enum btrace_format arg1)
 {
   return 0;
 }
 
 static int
-debug_supports_btrace (struct target_ops *self)
+debug_supports_btrace (struct target_ops *self, enum btrace_format arg1)
 {
   int result;
   fprintf_unfiltered (gdb_stdlog, "-> %s->to_supports_btrace (...)\n", debug_target.to_shortname);
-  result = debug_target.to_supports_btrace (&debug_target);
+  result = debug_target.to_supports_btrace (&debug_target, arg1);
   fprintf_unfiltered (gdb_stdlog, "<- %s->to_supports_btrace (", debug_target.to_shortname);
   target_debug_print_struct_target_ops_p (&debug_target);
+  fputs_unfiltered (", ", gdb_stdlog);
+  target_debug_print_enum_btrace_format (arg1);
   fputs_unfiltered (") = ", gdb_stdlog);
   target_debug_print_int (result);
   fputs_unfiltered ("\n", gdb_stdlog);
diff --git a/gdb/target.c b/gdb/target.c
index 763ddcb..d2f0050 100644
--- a/gdb/target.c
+++ b/gdb/target.c
@@ -3389,6 +3389,14 @@ target_ranged_break_num_registers (void)
 
 /* See target.h.  */
 
+int
+target_supports_btrace (enum btrace_format format)
+{
+  return current_target.to_supports_btrace (&current_target, format);
+}
+
+/* See target.h.  */
+
 struct btrace_target_info *
 target_enable_btrace (ptid_t ptid)
 {
diff --git a/gdb/target.h b/gdb/target.h
index 36fa3c6..803ef28 100644
--- a/gdb/target.h
+++ b/gdb/target.h
@@ -999,7 +999,7 @@ struct target_ops
       TARGET_DEFAULT_RETURN (0);
 
     /* Check whether the target supports branch tracing.  */
-    int (*to_supports_btrace) (struct target_ops *)
+    int (*to_supports_btrace) (struct target_ops *, enum btrace_format)
       TARGET_DEFAULT_RETURN (0);
 
     /* Enable branch tracing for PTID and allocate a branch trace target
@@ -2215,8 +2215,7 @@ extern void update_target_permissions (void);
 /* Imported from machine dependent code.  */
 
 /* See to_supports_btrace in struct target_ops.  */
-#define target_supports_btrace() \
-  (current_target.to_supports_btrace (&current_target))
+extern int target_supports_btrace (enum btrace_format);
 
 /* See to_enable_btrace in struct target_ops.  */
 extern struct btrace_target_info *target_enable_btrace (ptid_t ptid);
-- 
1.8.3.1