record-btrace: add (reverse-)stepping support

Provide to_resume and to_wait target methods for the btrace record target
to allow reverse stepping and replay support.

Replay is limited in the sense that only stepping and source correlation
are supported.  We do not record data and thus can not show variables.

Non-stop mode is not working.  Do not allow record-btrace in non-stop mode.

2014-01-16  Markus Metzger  <markus.t.metzger@intel.com>

	* btrace.h (btrace_thread_flag): New.
	(struct btrace_thread_info) <flags>: New.
	* record-btrace.c (record_btrace_resume_thread)
	(record_btrace_find_thread_to_move, btrace_step_no_history)
	(btrace_step_stopped, record_btrace_start_replaying)
	(record_btrace_step_thread, record_btrace_decr_pc_after_break)
	(record_btrace_find_resume_thread): New.
	(record_btrace_resume, record_btrace_wait): Extend.
	(record_btrace_can_execute_reverse): New.
	(record_btrace_open): Fail in non-stop mode.
	(record_btrace_set_replay): Split into this, ...
	(record_btrace_stop_replaying): ... this, ...
	(record_btrace_clear_histories): ... and this.
	(init_record_btrace_ops): Init to_can_execute_reverse.
	* NEWS: Announce it.

testsuite/
	* gdb.btrace/delta.exp: Check reverse stepi.
	* gdb.btrace/tailcall.exp: Update.  Add stepping tests.
	* gdb.btrace/finish.exp: New.
	* gdb.btrace/next.exp: New.
	* gdb.btrace/nexti.exp: New.
	* gdb.btrace/record_goto.c: Add comments.
	* gdb.btrace/step.exp: New.
	* gdb.btrace/stepi.exp: New.
	* gdb.btrace/multi-thread-step.c: New.
	* gdb.btrace/multi-thread-step.exp: New.
	* gdb.btrace/rn-dl-bind.c: New.
	* gdb.btrace/rn-dl-bind.exp: New.
	* gdb.btrace/data.c: New.
	* gdb.btrace/data.exp: New.
	* gdb.btrace/Makefile.in (EXECUTABLES): Add new.

doc/
	* gdb.texinfo: Document limited reverse/replay support
	for target record-btrace.

1 files changed, 52 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.btrace/rn-dl-bind.exp b/gdb/testsuite/gdb.btrace/rn-dl-bind.exp
new file mode 100644
index 0000000..2f2250a
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/rn-dl-bind.exp
@@ -0,0 +1,52 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2013 Free Software Foundation, Inc.
+#
+# Contributed by Intel Corp. <markus.t.metzger@intel.com>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+#
+# Test that we can reverse-next over the dynamic linker's symbol
+# lookup code.
+
+# check for btrace support
+if { [skip_btrace_tests] } { return -1 }
+
+# start inferior
+standard_testfile
+if [prepare_for_testing $testfile.exp $testfile $srcfile {c++ debug}] {
+    return -1
+}
+if ![runto_main] {
+    return -1
+}
+
+# trace the code for the call to test
+gdb_test_no_output "record btrace"
+gdb_test "next" ".*main\.2.*"
+
+# just dump the function-call-history to help debugging
+gdb_test_no_output "set record function-call-history-size 0"
+gdb_test "record function-call-history /cli 1" ".*"
+
+# check that we can reverse-next and next
+gdb_test "reverse-next" ".*main\.1.*"
+gdb_test "next" ".*main\.2.*"
+
+# now go into test and try to reverse-next and next over the library call
+gdb_test "reverse-step" ".*test\.3.*"
+gdb_test "reverse-step" ".*test\.2.*"
+gdb_test "reverse-next" ".*test\.1.*"
+gdb_test "next" ".*test\.2.*"