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[PATCH] btrace: no replay without history
- From: Markus Metzger <markus dot t dot metzger at intel dot com>
- To: palves at redhat dot com
- Cc: gdb-patches at sourceware dot org
- Date: Mon, 19 May 2014 15:16:21 +0200
- Subject: [PATCH] btrace: no replay without history
- Authentication-results: sourceware.org; auth=none
When using a reverse execution command without execution history, GDB
might end up in a state where replaying has been started but remains
at the current instruction. This state is illegal.
Do not step if there is no execution history to avoid this.
2014-05-19 Markus Metzger <markus.t.metzger@intel.com>
* record-btrace.c (record_btrace_step_thread): Check for empty history.
testsuite/
* gdb.btrace/nohist.exp: New.
---
gdb/record-btrace.c | 4 ++++
gdb/testsuite/gdb.btrace/nohist.exp | 46 +++++++++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+)
create mode 100644 gdb/testsuite/gdb.btrace/nohist.exp
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index bcac165..d768225 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1577,6 +1577,10 @@ record_btrace_step_thread (struct thread_info *tp)
enum btrace_thread_flag flags;
unsigned int steps;
+ /* We can't step without an execution history. */
+ if (btrace_is_empty (tp))
+ return btrace_step_no_history ();
+
btinfo = &tp->btrace;
replay = btinfo->replay;
diff --git a/gdb/testsuite/gdb.btrace/nohist.exp b/gdb/testsuite/gdb.btrace/nohist.exp
new file mode 100644
index 0000000..c0a1a87
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/nohist.exp
@@ -0,0 +1,46 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2014 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/>.
+
+# check for btrace support
+if { [skip_btrace_tests] } { return -1 }
+
+# start inferior
+standard_testfile x86-record_goto.S
+if [prepare_for_testing nohist.exp $testfile $srcfile] {
+ return -1
+}
+
+if ![runto_main] {
+ return -1
+}
+
+proc check_not_replaying {} {
+ gdb_test "info record" [join [list \
+ "Active record target: record-btrace" \
+ "Recorded 0 instructions in 0 functions for \[^\\\r\\\n\]*" \
+ ] "\r\n"]
+}
+
+gdb_test_no_output "record btrace"
+
+check_not_replaying
+
+gdb_test "reverse-continue" "No more reverse-execution history\.\r\n.*"
+
+check_not_replaying
--
1.8.3.1