btrace: add struct btrace_data

Add a structure to hold the branch trace data and an enum to describe
the format of that data.  So far, only BTS is supported.  Also added
a NONE format to indicate that no branch trace data is available.

This will make it easier to support different branch trace formats in
the future.

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

	* Makefile.in (SFILES): Add common/btrace-common.c.
	(COMMON_OBS): Add common/btrace-common.o.
	(btrace-common.o): Add build rules.
	* btrace.c (parse_xml_btrace): Update parameters.
	(parse_xml_btrace_block): Set format field.
	(btrace_add_pc, btrace_fetch): Use struct btrace_data.
	(do_btrace_data_cleanup, make_cleanup_btrace_data): New.
	(btrace_compute_ftrace): Split into this and...
	(btrace_compute_ftrace_bts): ...this.
	(btrace_stitch_trace): Split into this and...
	(btrace_stitch_bts): ...this.
	* btrace.h (parse_xml_btrace): Update parameters.
	(make_cleanup_btrace_data): New.
	* common/btrace-common.c: New.
	* common/btrace-common.h: Include common-defs.h.
	(btrace_block_s): Update comment.
	(btrace_format): New.
	(btrace_format_string): New.
	(btrace_data_bts): New.
	(btrace_data): New.
	(btrace_data_init, btrace_data_fini, btrace_data_empty): New.
	* remote.c (remote_read_btrace): Update parameters.
	* target.c (target_read_btrace): Update parameters.
	* target.h (target_read_btrace): Update parameters.
	(target_ops)<to_read_btrace>: Update parameters.
	* x86-linux-nat.c (x86_linux_read_btrace): Update parameters.
	* target-delegates.c: Regenerate.
	* target-debug (target_debug_print_struct_btrace_data_p): New.
	* nat/linux-btrace.c (linux_read_btrace): Split into this and...
	(linux_read_bts): ...this.
	* nat/linux-btrace.h (linux_read_btrace): Update parameters.

gdbserver/
	* Makefile.in (SFILES): Add common/btrace-common.c.
	(OBS): Add common/btrace-common.o.
	(btrace-common.o): Add build rules.
	* linux-low: Include btrace-common.h.
	(linux_low_read_btrace): Use struct btrace_data.  Call
	btrace_data_init and btrace_data_fini.

gdb/nat/linux-btrace.c

@@ -495,12 +495,13 @@ linux_btrace_has_changed (struct btrace_target_info *tinfo)
   return header->data_head != tinfo->data_head;
 }
 
-/* See linux-btrace.h.  */
+/* Read branch trace data in BTS format for the thread given by TINFO into
+   BTRACE using the TYPE reading method.  */
 
-enum btrace_error
-linux_read_btrace (VEC (btrace_block_s) **btrace,
-		   struct btrace_target_info *tinfo,
-		   enum btrace_read_type type)
+static enum btrace_error
+linux_read_bts (struct btrace_data_bts *btrace,
+		struct btrace_target_info *tinfo,
+		enum btrace_read_type type)
 {
   volatile struct perf_event_mmap_page *header;
   const uint8_t *begin, *end, *start;
@@ -522,7 +523,7 @@ linux_read_btrace (VEC (btrace_block_s) **btrace,
       data_head = header->data_head;
 
       /* Delete any leftover trace from the previous iteration.  */
-      VEC_free (btrace_block_s, *btrace);
+      VEC_free (btrace_block_s, btrace->blocks);
 
       if (type == BTRACE_READ_DELTA)
 	{
@@ -559,7 +560,7 @@ linux_read_btrace (VEC (btrace_block_s) **btrace,
       else
 	end = perf_event_buffer_end (tinfo);
 
-      *btrace = perf_event_read_bts (tinfo, begin, end, start, size);
+      btrace->blocks = perf_event_read_bts (tinfo, begin, end, start, size);
 
       /* The stopping thread notifies its ptracer before it is scheduled out.
 	 On multi-core systems, the debugger might therefore run while the
@@ -575,12 +576,27 @@ linux_read_btrace (VEC (btrace_block_s) **btrace,
   /* Prune the incomplete last block (i.e. the first one of inferior execution)
      if we're not doing a delta read.  There is no way of filling in its zeroed
      BEGIN element.  */
-  if (!VEC_empty (btrace_block_s, *btrace) && type != BTRACE_READ_DELTA)
-    VEC_pop (btrace_block_s, *btrace);
+  if (!VEC_empty (btrace_block_s, btrace->blocks)
+      && type != BTRACE_READ_DELTA)
+    VEC_pop (btrace_block_s, btrace->blocks);
 
   return BTRACE_ERR_NONE;
 }
 
+/* See linux-btrace.h.  */
+
+enum btrace_error
+linux_read_btrace (struct btrace_data *btrace,
+		   struct btrace_target_info *tinfo,
+		   enum btrace_read_type type)
+{
+  /* We read btrace in BTS format.  */
+  btrace->format = BTRACE_FORMAT_BTS;
+  btrace->variant.bts.blocks = NULL;
+
+  return linux_read_bts (&btrace->variant.bts, tinfo, type);
+}
+
 #else /* !HAVE_LINUX_PERF_EVENT_H */
 
 /* See linux-btrace.h.  */
@@ -610,7 +626,7 @@ linux_disable_btrace (struct btrace_target_info *tinfo)
 /* See linux-btrace.h.  */
 
 enum btrace_error
-linux_read_btrace (VEC (btrace_block_s) **btrace,
+linux_read_btrace (struct btrace_data *btrace,
 		   struct btrace_target_info *tinfo,
 		   enum btrace_read_type type)
 {

gdb/nat/linux-btrace.h

@@ -70,7 +70,7 @@ extern struct btrace_target_info *linux_enable_btrace (ptid_t ptid);
 extern enum btrace_error linux_disable_btrace (struct btrace_target_info *ti);
 
 /* See to_read_btrace in target.h.  */
-extern enum btrace_error linux_read_btrace (VEC (btrace_block_s) **btrace,
+extern enum btrace_error linux_read_btrace (struct btrace_data *btrace,
 					    struct btrace_target_info *btinfo,
 					    enum btrace_read_type type);