gdb, btrace: make record-btrace per-inferior

When there is more than one inferior, the "record btrace" command should
only apply to the current inferior.

gdb/ChangeLog:

2020-03-19  Markus Metzger  <markus.t.metzger@intel.com>

	* record-btrace.c (record_btrace_enable_warn): Ignore thread if
	its inferior is not recorded by us.
	(record_btrace_target_open): Replace call to all_non_exited_threads ()
	with call to current_inferior ()->non_exited_threads ().
	(record_btrace_target::stop_recording): Likewise.
	(record_btrace_target::close): Likewise.
	(record_btrace_target::wait): Likewise.
	(record_btrace_target::record_stop_replaying): Likewise.

gdb/testsuite/ChangeLog:

2020-03-19  Markus Metzger  <markus.t.metzger@intel.com>

	* gdb.btrace/multi-inferior.c: New test.
	* gdb.btrace/multi-inferior.exp: New file.

5 files changed, 121 insertions, 5 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 05110002e78..bdec0f39079 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
 2020-04-21  Markus Metzger  <markus.t.metzger@intel.com>
 
+	* record-btrace.c (record_btrace_enable_warn): Ignore thread if
+	its inferior is not recorded by us.
+	(record_btrace_target_open): Replace call to
+	all_non_exited_threads () with call to current_inferior
+	()->non_exited_threads ().
+	(record_btrace_target::stop_recording): Likewise.
+	(record_btrace_target::close): Likewise.
+	(record_btrace_target::wait): Likewise.
+	(record_btrace_target::record_stop_replaying): Likewise.
+
+2020-04-21  Markus Metzger  <markus.t.metzger@intel.com>
+
 	* btrace.c (btrace_enable): Throw an error on double enables and
 	when enabling recording fails.
 	(btrace_disable): Throw an error if the thread is not recorded.
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 9b04d060149..226d56dfe37 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -284,6 +284,11 @@ require_btrace (void)
 static void
 record_btrace_enable_warn (struct thread_info *tp)
 {
+  /* Ignore this thread if its inferior is not recorded by us.  */
+  target_ops *rec = tp->inf->target_at (record_stratum);
+  if (rec != &record_btrace_ops)
+    return;
+
   try
     {
       btrace_enable (tp, &record_btrace_conf);
@@ -387,7 +392,7 @@ record_btrace_target_open (const char *args, int from_tty)
   if (!target_has_execution)
     error (_("The program is not being run."));
 
-  for (thread_info *tp : all_non_exited_threads ())
+  for (thread_info *tp : current_inferior ()->non_exited_threads ())
     if (args == NULL || *args == 0 || number_is_in_list (args, tp->global_num))
       {
 	btrace_enable (tp, &record_btrace_conf);
@@ -409,7 +414,7 @@ record_btrace_target::stop_recording ()
 
   record_btrace_auto_disable ();
 
-  for (thread_info *tp : all_non_exited_threads ())
+  for (thread_info *tp : current_inferior ()->non_exited_threads ())
     if (tp->btrace.target != NULL)
       btrace_disable (tp);
 }
@@ -443,7 +448,7 @@ record_btrace_target::close ()
 
   /* We should have already stopped recording.
      Tear down btrace in case we have not.  */
-  for (thread_info *tp : all_non_exited_threads ())
+  for (thread_info *tp : current_inferior ()->non_exited_threads ())
     btrace_teardown (tp);
 }
 
@@ -2630,7 +2635,7 @@ record_btrace_target::wait (ptid_t ptid, struct target_waitstatus *status,
   /* Stop all other threads. */
   if (!target_is_non_stop_p ())
     {
-      for (thread_info *tp : all_non_exited_threads ())
+      for (thread_info *tp : current_inferior ()->non_exited_threads ())
 	record_btrace_cancel_resume (tp);
     }
 
@@ -2867,7 +2872,7 @@ record_btrace_target::goto_record (ULONGEST insn)
 void
 record_btrace_target::record_stop_replaying ()
 {
-  for (thread_info *tp : all_non_exited_threads ())
+  for (thread_info *tp : current_inferior ()->non_exited_threads ())
     record_btrace_stop_replaying (tp);
 }
 
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 09ad4cd3d23..038df8634b2 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2020-04-21  Markus Metzger  <markus.t.metzger@intel.com>
 
+	* gdb.btrace/multi-inferior.c: New test.
+	* gdb.btrace/multi-inferior.exp: New file.
+
+2020-04-21  Markus Metzger  <markus.t.metzger@intel.com>
+
 	* gdb.btrace/enable-new-thread.c: New test.
 	* gdb.btrace/enable-new-thread.exp: New file.
 
diff --git a/gdb/testsuite/gdb.btrace/multi-inferior.c b/gdb/testsuite/gdb.btrace/multi-inferior.c
new file mode 100644
index 00000000000..9d7b2f1a4c2
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/multi-inferior.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2020 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/>.  */
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.btrace/multi-inferior.exp b/gdb/testsuite/gdb.btrace/multi-inferior.exp
new file mode 100644
index 00000000000..87a99332e03
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/multi-inferior.exp
@@ -0,0 +1,72 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2020 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/>.
+
+# Test that recording is per-inferior.
+#
+# When recording an inferior, threads from other inferiors, both existing
+# and newly created, are not automatically recorded.
+#
+# Each inferior can be recorded separately.
+
+if { [skip_btrace_tests] } {
+    unsupported "target does not support record-btrace"
+    return -1
+}
+
+standard_testfile
+if [prepare_for_testing "failed to prepare" $testfile {} {debug}] {
+    return -1
+}
+
+with_test_prefix "inferior 1" {
+    if ![runto_main] {
+	untested "failed to run to main"
+	return -1
+    }
+}
+
+with_test_prefix "inferior 2" {
+    gdb_test "add-inferior -exec ${binfile}" "Added inferior 2.*"
+    gdb_test "inferior 2" "Switching to inferior 2.*"
+
+    if ![runto_main] {
+	untested "inferior 2: failed to run to main"
+	return -1
+    }
+
+    gdb_test_no_output "record btrace" "record btrace"
+}
+
+with_test_prefix "inferior 1" {
+    gdb_test "inferior 1" "Switching to inferior 1.*"
+
+    gdb_test "info record" "No record target is currently active\\."
+    gdb_test_no_output "record btrace" "record btrace"
+}
+
+with_test_prefix "inferior 3" {
+    gdb_test "add-inferior -exec ${binfile}" "Added inferior 3.*"
+    gdb_test "inferior 3" "Switching to inferior 3.*"
+
+    if ![runto_main] {
+	untested "inferior 3: failed to run to main"
+	return -1
+    }
+
+    gdb_test "info record" "No record target is currently active\\."
+    gdb_test_no_output "record btrace" "record btrace"
+}