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.

gdb/ChangeLog

@@ -1,3 +1,16 @@
+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.
+
 2014-03-06  Yao Qi  <yao@codesourcery.com>
 
 	* target.h (struct target_ops) <to_traceframe_info>: Use

gdb/mi/mi-main.c

@@ -2483,8 +2483,7 @@ mi_cmd_trace_find (char *command, char **argv, int argc)
       return;
     }
 
-  if (current_trace_status ()->running)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
 
   if (strcmp (mode, "frame-number") == 0)
     {

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

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.*"

gdb/tracepoint.c

@@ -2443,6 +2443,15 @@ tfind_1 (enum trace_find_type type, int num,
     }
 }
 
+/* Error on looking at traceframes while trace is running.  */
+
+void
+check_trace_running (struct trace_status *status)
+{
+  if (status->running && status->filename == NULL)
+    error (_("May not look at trace frames while trace is running."));
+}
+
 /* trace_find_command takes a trace frame number n, 
    sends "QTFrame:<n>" to the target, 
    and accepts a reply that may contain several optional pieces
@@ -2463,9 +2472,7 @@ trace_find_command (char *args, int from_tty)
 { /* This should only be called with a numeric argument.  */
   int frameno = -1;
 
-  if (current_trace_status ()->running
-      && current_trace_status ()->filename == NULL)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
   
   if (args == 0 || *args == 0)
     { /* TFIND with no args means find NEXT trace frame.  */
@@ -2515,9 +2522,7 @@ trace_find_pc_command (char *args, int from_tty)
 {
   CORE_ADDR pc;
 
-  if (current_trace_status ()->running
-      && current_trace_status ()->filename == NULL)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
 
   if (args == 0 || *args == 0)
     pc = regcache_read_pc (get_current_regcache ());
@@ -2534,9 +2539,7 @@ trace_find_tracepoint_command (char *args, int from_tty)
   int tdp;
   struct tracepoint *tp;
 
-  if (current_trace_status ()->running
-      && current_trace_status ()->filename == NULL)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
 
   if (args == 0 || *args == 0)
     {
@@ -2574,9 +2577,7 @@ trace_find_line_command (char *args, int from_tty)
   struct symtab_and_line sal;
   struct cleanup *old_chain;
 
-  if (current_trace_status ()->running
-      && current_trace_status ()->filename == NULL)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
 
   if (args == 0 || *args == 0)
     {
@@ -2640,9 +2641,7 @@ trace_find_range_command (char *args, int from_tty)
   static CORE_ADDR start, stop;
   char *tmp;
 
-  if (current_trace_status ()->running
-      && current_trace_status ()->filename == NULL)
-    error (_("May not look at trace frames while trace is running."));
+  check_trace_running (current_trace_status ());
 
   if (args == 0 || *args == 0)
     { /* XXX FIXME: what should default behavior be?  */

gdb/tracepoint.h

@@ -334,6 +334,8 @@ extern void query_if_trace_running (int from_tty);
 extern void disconnect_tracing (void);
 extern void trace_reset_local_state (void);
 
+extern void check_trace_running (struct trace_status *);
+
 extern void start_tracing (char *notes);
 extern void stop_tracing (char *notes);