btrace: maintenance commands

Add maintenance commands that help debugging the btrace record target.
The following new commands are added:

maint info btrace
  Print information about branch tracing internals.

maint btrace packet-history
  Print the raw branch tracing data.

maint btrace clear-packet-history
  Discard the stored raw branch tracing data.

maint btrace clear
  Discard all branch tracing data.  It will be fetched and processed
  anew by the next "record" command.

maint set|show btrace pt skip-pad
  Set and show whether PAD packets are skipped when computing the
  packet history.

gdb/
	* btrace.c: Include gdbcmd.h, cli/cli-utils.h, and ctype.h.
	(maint_btrace_cmdlist, maint_btrace_set_cmdlist)
	(maint_btrace_show_cmdlist, maint_btrace_pt_set_cmdlist)
	(maint_btrace_pt_show_cmdlist, maint_btrace_pt_skip_pad)
	(btrace_maint_clear): New.
	(btrace_fetch, btrace_clear): Call btrace_maint_clear.
	(pt_print_packet, btrace_maint_decode_pt)
	(btrace_maint_update_pt_packets, btrace_maint_update_packets)
	(btrace_maint_print_packets, get_uint, get_context_size, no_chunk)
	(maint_btrace_packet_history_cmd)
	(maint_btrace_clear_packet_history_cmd, maint_btrace_clear_cmd)
	(maint_btrace_cmd, maint_btrace_set_cmd, maint_btrace_show_cmd)
	(maint_btrace_pt_set_cmd, maint_btrace_pt_show_cmd)
	(maint_info_btrace_cmd, _initialize_btrace): New.
	* btrace.h (btrace_pt_packet, btrace_pt_packet_s)
	(btrace_maint_packet_history, btrace_maint_info): New.
	(btrace_thread_info) <maint>: New.
	* NEWS: Announce it.

doc/
	* gdb.texinfo (Maintenance Commands): Document "maint btrace"
	commands.

2 files changed, 65 insertions, 0 deletions

diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog
index 6d898f3..18d9039 100644
--- a/gdb/doc/ChangeLog
+++ b/gdb/doc/ChangeLog
@@ -1,5 +1,10 @@
 2015-07-02  Markus Metzger  <markus.t.metzger@intel.com>
 
+        * gdb.texinfo (Maintenance Commands): Document "maint btrace"
+	commands.
+
+2015-07-02  Markus Metzger  <markus.t.metzger@intel.com>
+
 	* gdb.texinfo (Process Record and Replay): Spell out that variables
 	and registers are not available during btrace replay.
 	Describe the new "record btrace pt" command.
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a19ee6d..812917b 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -33980,6 +33980,66 @@ Shared library events.
 This prints information about each @code{bfd} object that is known to
 @value{GDBN}.  @xref{Top, , BFD, bfd, The Binary File Descriptor Library}.
 
+@kindex maint info btrace
+@item maint info btrace
+Pint information about raw branch tracing data.
+
+@kindex maint btrace packet-history
+@item maint btrace packet-history
+Print the raw branch trace packets that are used to compute the
+execution history for the @samp{record btrace} command.  Both the
+information and the format in which it is printed depend on the btrace
+recording format.
+
+@table @code
+@item bts
+For the BTS recording format, print a list of blocks of sequential
+code.  For each block, the following information is printed:
+
+@table @asis
+@item Block number
+Newer blocks have higher numbers.  The oldest block has number zero.
+@item Lowest @samp{PC}
+@item Highest @samp{PC}
+@end table
+
+@item pt
+For the Intel(R) Processor Trace recording format, print a list of
+Intel(R) Processor Trace packets.  For each packet, the following
+information is printed:
+
+@table @asis
+@item Packet number
+Newer packets have higher numbers.  The oldest packet has number zero.
+@item Trace offset
+The packet's offset in the trace stream.
+@item Packet opcode and payload
+@end table
+@end table
+
+@kindex maint btrace clear-packet-history
+@item maint btrace clear-packet-history
+Discards the cached packet history printed by the @samp{maint btrace
+packet-history} command.  The history will be computed again when
+needed.
+
+@kindex maint btrace clear
+@item maint btrace clear
+Discard the branch trace data.  The data will be fetched anew and the
+branch trace will be recomputed when needed.
+
+This implicitly truncates the branch trace to a single branch trace
+buffer.  When updating branch trace incrementally, the branch trace
+available to @value{GDBN} may be bigger than a single branch trace
+buffer.
+
+@kindex maint set btrace pt skip-pad
+@item maint set btrace pt skip-pad
+@kindex maint show btrace pt skip-pad
+@item maint show btrace pt skip-pad
+Control whether @value{GDBN} will skip PAD packets when computing the
+packet history.
+
 @kindex set displaced-stepping
 @kindex show displaced-stepping
 @cindex displaced stepping support