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* [binutils-gdb] gdb, btrace: forward fetch_registers for unknown threads
@ 2020-04-21 13:56 Markus Metzger
0 siblings, 0 replies; only message in thread
From: Markus Metzger @ 2020-04-21 13:56 UTC (permalink / raw)
To: gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=1a476b6d68f338e6daa0345501c0cf0fe97dd8f3
commit 1a476b6d68f338e6daa0345501c0cf0fe97dd8f3
Author: Markus Metzger <markus.t.metzger@intel.com>
Date: Wed Mar 18 10:53:41 2020 +0100
gdb, btrace: forward fetch_registers for unknown threads
In the record-btrace target, while replaying, we can only provide the PC
register. The btrace state is stored in the thread_info. So, when trying
to determine whether we are currently replaying, GDB calls
find_thread_ptid() to obtain the thread_info. It also asserts that we do
have a thread_info.
For new threads, libthread-db may fetch registers before the thread is
known to GDB. In this case, find_thread_ptid() returns nullptr and the
assertion fails.
Forward the fetch_registers request to the target beneath in that case.
gdb/ChangeLog:
2020-03-19 Markus Metzger <markus.t.metzger@intel.com>
* record-btrace.c (record_btrace_target::fetch_registers): Forward
request if we do not have a thread_info.
gdb/testsuite/ChangeLog:
2020-03-19 Markus Metzger <markus.t.metzger@intel.com>
* gdb.btrace/enable-new-thread.c: New test.
* gdb.btrace/enable-new-thread.exp: New file.
Diff:
---
gdb/ChangeLog | 5 +++
gdb/record-btrace.c | 11 +++--
gdb/testsuite/ChangeLog | 5 +++
gdb/testsuite/gdb.btrace/enable-new-thread.c | 36 ++++++++++++++++
gdb/testsuite/gdb.btrace/enable-new-thread.exp | 57 ++++++++++++++++++++++++++
5 files changed, 111 insertions(+), 3 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 0e80cdb2d16..c761d498b7f 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-21 Markus Metzger <markus.t.metzger@intel.com>
+
+ * record-btrace.c (record_btrace_target::fetch_registers): Forward
+ request if we do not have a thread_info.
+
2020-04-21 Tom de Vries <tdevries@suse.de>
PR gdb/25471
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index fe2ab8ad9a9..9b04d060149 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -1532,11 +1532,16 @@ record_btrace_target::remove_breakpoint (struct gdbarch *gdbarch,
void
record_btrace_target::fetch_registers (struct regcache *regcache, int regno)
{
+ btrace_insn_iterator *replay = nullptr;
+
+ /* Thread-db may ask for a thread's registers before GDB knows about the
+ thread. We forward the request to the target beneath in this
+ case. */
thread_info *tp = find_thread_ptid (regcache->target (), regcache->ptid ());
- gdb_assert (tp != NULL);
+ if (tp != nullptr)
+ replay = tp->btrace.replay;
- btrace_insn_iterator *replay = tp->btrace.replay;
- if (replay != NULL && !record_btrace_generating_corefile)
+ if (replay != nullptr && !record_btrace_generating_corefile)
{
const struct btrace_insn *insn;
struct gdbarch *gdbarch;
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index f72256730f3..09ad4cd3d23 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+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.
+
2020-04-21 Tom de Vries <tdevries@suse.de>
PR gdb/25471
diff --git a/gdb/testsuite/gdb.btrace/enable-new-thread.c b/gdb/testsuite/gdb.btrace/enable-new-thread.c
new file mode 100644
index 00000000000..d4dc240e314
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/enable-new-thread.c
@@ -0,0 +1,36 @@
+/* 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/>. */
+
+#include <pthread.h>
+#include <unistd.h>
+
+static void *
+test (void *arg)
+{
+ return arg; /* bp.1 */
+}
+
+int
+main (void)
+{
+ pthread_t th;
+
+ pthread_create (&th, NULL, test, NULL);
+ pthread_join (th, NULL);
+
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.btrace/enable-new-thread.exp b/gdb/testsuite/gdb.btrace/enable-new-thread.exp
new file mode 100644
index 00000000000..e8b17ad0ba2
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/enable-new-thread.exp
@@ -0,0 +1,57 @@
+# 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 new threads of recorded inferiors also get recorded.
+
+if { [skip_btrace_tests] } {
+ unsupported "target does not support record-btrace"
+ return -1
+}
+
+standard_testfile
+if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug pthreads}] {
+ return -1
+}
+
+if ![runto_main] {
+ untested "failed to run to main"
+ return -1
+}
+
+# Record the main thread. Recording will automatically be enabled for the
+# other thread.
+gdb_test "record btrace"
+
+gdb_breakpoint [gdb_get_line_number "bp.1" $srcfile]
+gdb_continue_to_breakpoint "cont to bp.1" ".*/\\* bp\.1 \\*/.*"
+
+proc check_thread_recorded { num } {
+ global decimal
+
+ with_test_prefix "thread $num" {
+ gdb_test "thread $num" "Switching to thread $num.*"
+
+ gdb_test "info record" [multi_line \
+ "Active record target: record-btrace" \
+ ".*" \
+ "Recorded $decimal instructions in $decimal functions \[^\\\r\\\n\]*" \
+ ]
+ }
+}
+
+check_thread_recorded 1
+check_thread_recorded 2
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