[PATCH v2 06/12] python: Add clear() to gdb.Record.

[Felix Willgerodt]

This function allows to clear the trace data from python, forcing to
re-decode the trace for successive commands.

gdb/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* py-record-btrace.c (recpy_bt_clear): New function.
	* py-record-btrace.h (recpy_bt_clear): New export.
	* py-record.c (recpy_clear): New function.
	(recpy_record_methods): Add clear().

testsuite/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* gdb.python/py-record-btrace.exp: Add tests for clear().

gdb/doc/ChangeLog:
2021-06-14  Felix Willgerodt  <felix.willgerodt@intel.com>

	* python.texi (gdb.Record): Document clear().
---
 gdb/doc/python.texi                           |  5 +++++
 gdb/python/py-record-btrace.c                 | 13 +++++++++++++
 gdb/python/py-record-btrace.h                 |  3 +++
 gdb/python/py-record.c                        | 16 ++++++++++++++++
 gdb/testsuite/gdb.python/py-record-btrace.exp |  6 +++++-
 5 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 333732f42f2..fa1c69a2283 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -3567,6 +3567,11 @@ A @code{gdb.Record} object has the following methods:
 Move the replay position to the given @var{instruction}.
 @end defun
 
+@defun Record.clear ()
+Clear the trace data of the current recording.  This forces re-decoding of the
+trace for successive commands.
+@end defun
+
 The common @code{gdb.Instruction} class that recording method specific
 instruction objects inherit from, has the following attributes:
 
diff --git a/gdb/python/py-record-btrace.c b/gdb/python/py-record-btrace.c
index 128dd14dd81..97649b206a5 100644
--- a/gdb/python/py-record-btrace.c
+++ b/gdb/python/py-record-btrace.c
@@ -815,6 +815,19 @@ recpy_bt_goto (PyObject *self, PyObject *args)
   Py_RETURN_NONE;
 }
 
+/* Implementation of BtraceRecord.clear (self) -> None.  */
+
+PyObject *
+recpy_bt_clear (PyObject *self, PyObject *args)
+{
+  const recpy_record_object * const record = (recpy_record_object *) self;
+  thread_info *const tinfo = record->thread;
+
+  btrace_clear (tinfo);
+
+  Py_RETURN_NONE;
+}
+
 /* BtraceList methods.  */
 
 static PyMethodDef btpy_list_methods[] =
diff --git a/gdb/python/py-record-btrace.h b/gdb/python/py-record-btrace.h
index 0022704883e..adb03c5eab4 100644
--- a/gdb/python/py-record-btrace.h
+++ b/gdb/python/py-record-btrace.h
@@ -31,6 +31,9 @@ extern PyObject *recpy_bt_format (PyObject *self, void *closure);
 /* Implementation of record.goto (instruction) -> None.  */
 extern PyObject *recpy_bt_goto (PyObject *self, PyObject *value);
 
+/* Implementation of BtraceRecord.clear (self) -> None.  */
+extern PyObject *recpy_bt_clear (PyObject *self, PyObject *args);
+
 /* Implementation of record.instruction_history [list].  */
 extern PyObject *recpy_bt_instruction_history (PyObject *self, void *closure);
 
diff --git a/gdb/python/py-record.c b/gdb/python/py-record.c
index 481cd282ba3..9b46b2452bf 100644
--- a/gdb/python/py-record.c
+++ b/gdb/python/py-record.c
@@ -127,6 +127,19 @@ recpy_goto (PyObject *self, PyObject *value)
   return PyErr_Format (PyExc_NotImplementedError, _("Not implemented."));
 }
 
+/* Implementation of record.clear () -> None.  */
+
+static PyObject *
+recpy_clear (PyObject *self, PyObject *value)
+{
+  const recpy_record_object * const obj = (recpy_record_object *) self;
+
+  if (obj->method == RECORD_METHOD_BTRACE)
+    return recpy_bt_clear (self, value);
+
+  return PyErr_Format (PyExc_NotImplementedError, _("Not implemented."));
+}
+
 /* Implementation of record.replay_position [instruction]  */
 
 static PyObject *
@@ -538,6 +551,9 @@ static PyMethodDef recpy_record_methods[] = {
   { "goto", recpy_goto, METH_VARARGS,
     "goto (instruction|function_call) -> None.\n\
 Rewind to given location."},
+  { "clear", recpy_clear, METH_VARARGS,
+    "clear () -> None.\n\
+Clears the trace."},
   { NULL }
 };
 
diff --git a/gdb/testsuite/gdb.python/py-record-btrace.exp b/gdb/testsuite/gdb.python/py-record-btrace.exp
index bf0fa18720e..7d45d6728a3 100644
--- a/gdb/testsuite/gdb.python/py-record-btrace.exp
+++ b/gdb/testsuite/gdb.python/py-record-btrace.exp
@@ -93,7 +93,11 @@ with_test_prefix "instruction " {
     }
     gdb_test "python print(i.decoded)" ".*"
     gdb_test "python print(i.size)" "$decimal"
-    gdb_test "python print(i.is_speculative)" "False"
+    gdb_test "python print(i.is_speculative)" "False"    
+    gdb_test_no_output "python r.clear()"
+    gdb_test "python insn = r.instruction_history"
+    gdb_test_no_output "python i = insn\[0\]"
+    gdb_test "python print(i.size)" "$decimal"
 }
 
 with_test_prefix "function call" {
-- 
2.25.4

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928