Fix PR16508

This patch fixes PR16508, which is about MI "-trace-find frame-number 0"
behaves differently from CLI "tfind 0".  In CLI, we check both
status->running and status->filename, but in MI, we only check
status->running, which looks wrong to me.  This patch moves the code
of checking to a new function check_trace_running, and use it in
both CLI and MI.

This patch also adds a test case pr16508.exp, which fails without this
fix, and passes with the fix applied.

  FAIL: gdb.trace/pr16508.exp: interpreter-exec mi "-trace-find frame-number 0"

gdb:

2014-03-06  Yao Qi  <yao@codesourcery.com>

	PR breakpoints/16508
	* tracepoint.c (check_trace_running): New function.
	(trace_find_command): Move code to check_trace_running and
	call check_trace_running.
	(trace_find_pc_command): Likewise.
	(trace_find_tracepoint_command): Likewise.
	(trace_find_line_command): Likewise.
	(trace_find_range_command): Likewise.
	* tracepoint.h (check_trace_running): Likewise.
	* mi/mi-main.c (mi_cmd_trace_find): Call check_trace_running.

gdb/testsuite:

2014-03-06  Yao Qi  <yao@codesourcery.com>

	* gdb.trace/pr16508.exp: New file.

2 files changed, 67 insertions, 0 deletions

diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 65b4f95..a078554 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2014-03-06  Yao Qi  <yao@codesourcery.com>
+
+	* gdb.trace/pr16508.exp: New file.
+
 2014-03-05  Pedro Alves  <palves@redhat.com>
 
 	PR gdb/16575
diff --git a/gdb/testsuite/gdb.trace/pr16508.exp b/gdb/testsuite/gdb.trace/pr16508.exp
new file mode 100644
index 0000000..ff01b40
--- /dev/null
+++ b/gdb/testsuite/gdb.trace/pr16508.exp
@@ -0,0 +1,63 @@
+# Copyright 2014 Free Software Foundation, Inc.
+# 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/>.
+
+load_lib "trace-support.exp"
+
+standard_testfile read-memory.c
+set executable $testfile
+
+if [prepare_for_testing "failed to prepare for trace tests" \
+	$executable $srcfile [list debug]] {
+    return -1
+}
+
+if ![runto_main] {
+    fail "Can't run to main to check for trace support"
+    return -1
+}
+
+if ![gdb_target_supports_trace] {
+    unsupported "target does not support trace"
+    return -1
+}
+
+gdb_test "trace start" ".*"
+gdb_breakpoint "end"
+
+gdb_test_no_output "tstart"
+
+gdb_test "continue" ".*Breakpoint \[0-9\]+, end .*"
+
+set tracefile [standard_output_file ${testfile}]
+
+# Save trace frames to tfile.
+gdb_test "tsave ${tracefile}.tf" \
+    "Trace data saved to file '${tracefile}.tf'.*" \
+    "save tfile trace file"
+
+# Change target to tfile.
+set test "change to tfile target"
+gdb_test_multiple "target tfile ${tracefile}.tf" "$test" {
+    -re "A program is being debugged already.  Kill it. .y or n. " {
+	send_gdb "y\n"
+	exp_continue
+    }
+    -re "$gdb_prompt $" {
+	pass "$test"
+    }
+}
+
+gdb_test "tfind 0" "Found trace frame 0, tracepoint .*"
+
+gdb_test "interpreter-exec mi \"-trace-find frame-number 0\"" "done.*"