[PATCH v20 15/21] perf python: Expose brstack in sample event

[Ian Rogers]

Implement pyrf_branch_entry and pyrf_branch_stack for lazy
iteration over branch stack entries.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/python.c | 198 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index db7f4a8ebcd1..05691a513184 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -22,6 +22,7 @@
 #include "debug.h"
 #include "dso.h"
 #include "event.h"
+#include "branch.h"
 #include "evlist.h"
 #include "evsel.h"
 #include "expr.h"
@@ -89,6 +90,8 @@ struct pyrf_event {
 	bool al_resolved;
 	/** @callchain: Resolved callchain, eagerly computed if requested. */
 	PyObject *callchain;
+	/** @brstack: Resolved branch stack, eagerly computed if requested. */
+	PyObject *brstack;
 	/** @event: The underlying perf_event that may be in a file or ring buffer. */
 	union perf_event event;
 };
@@ -127,6 +130,7 @@ static void pyrf_event__delete(struct pyrf_event *pevent)
 	if (pevent->al_resolved)
 		addr_location__exit(&pevent->al);
 	Py_XDECREF(pevent->callchain);
+	Py_XDECREF(pevent->brstack);
 	perf_sample__exit(&pevent->sample);
 	Py_TYPE(pevent)->tp_free((PyObject *)pevent);
 }
@@ -997,6 +1001,154 @@ static PyObject *pyrf_sample_event__get_callchain(PyObject *self, void *closure
 	return pevent->callchain;
 }
 
+struct pyrf_branch_entry {
+	PyObject_HEAD
+	u64 from;
+	u64 to;
+	struct branch_flags flags;
+};
+
+static void pyrf_branch_entry__delete(struct pyrf_branch_entry *pentry)
+{
+	Py_TYPE(pentry)->tp_free((PyObject *)pentry);
+}
+
+static PyObject *pyrf_branch_entry__get_from(struct pyrf_branch_entry *pentry,
+					     void *closure __maybe_unused)
+{
+	return PyLong_FromUnsignedLongLong(pentry->from);
+}
+
+static PyObject *pyrf_branch_entry__get_to(struct pyrf_branch_entry *pentry,
+					   void *closure __maybe_unused)
+{
+	return PyLong_FromUnsignedLongLong(pentry->to);
+}
+
+static PyObject *pyrf_branch_entry__get_mispred(struct pyrf_branch_entry *pentry,
+						void *closure __maybe_unused)
+{
+	return PyBool_FromLong(pentry->flags.mispred);
+}
+
+static PyObject *pyrf_branch_entry__get_predicted(struct pyrf_branch_entry *pentry,
+						  void *closure __maybe_unused)
+{
+	return PyBool_FromLong(pentry->flags.predicted);
+}
+
+static PyObject *pyrf_branch_entry__get_in_tx(struct pyrf_branch_entry *pentry,
+					      void *closure __maybe_unused)
+{
+	return PyBool_FromLong(pentry->flags.in_tx);
+}
+
+static PyObject *pyrf_branch_entry__get_abort(struct pyrf_branch_entry *pentry,
+					      void *closure __maybe_unused)
+{
+	return PyBool_FromLong(pentry->flags.abort);
+}
+
+static PyObject *pyrf_branch_entry__get_cycles(struct pyrf_branch_entry *pentry,
+					       void *closure __maybe_unused)
+{
+	return PyLong_FromUnsignedLongLong(pentry->flags.cycles);
+}
+
+static PyObject *pyrf_branch_entry__get_type(struct pyrf_branch_entry *pentry,
+					     void *closure __maybe_unused)
+{
+	return PyLong_FromUnsignedLongLong((unsigned long long)pentry->flags.type);
+}
+
+static PyGetSetDef pyrf_branch_entry__getset[] = {
+	{ .name = "from_ip",      .get = (getter)pyrf_branch_entry__get_from, },
+	{ .name = "to_ip",        .get = (getter)pyrf_branch_entry__get_to, },
+	{ .name = "mispred",   .get = (getter)pyrf_branch_entry__get_mispred, },
+	{ .name = "predicted", .get = (getter)pyrf_branch_entry__get_predicted, },
+	{ .name = "in_tx",     .get = (getter)pyrf_branch_entry__get_in_tx, },
+	{ .name = "abort",     .get = (getter)pyrf_branch_entry__get_abort, },
+	{ .name = "cycles",    .get = (getter)pyrf_branch_entry__get_cycles, },
+	{ .name = "type",      .get = (getter)pyrf_branch_entry__get_type, },
+	{ .name = NULL, },
+};
+
+static PyTypeObject pyrf_branch_entry__type = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name	= "perf.branch_entry",
+	.tp_basicsize	= sizeof(struct pyrf_branch_entry),
+	.tp_dealloc	= (destructor)pyrf_branch_entry__delete,
+	.tp_flags	= Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+	.tp_doc		= "perf branch entry object.",
+	.tp_getset	= pyrf_branch_entry__getset,
+};
+
+struct pyrf_branch_stack {
+	PyObject_HEAD
+	struct branch_entry *entries;
+	u64 nr;
+};
+
+static void pyrf_branch_stack__delete(struct pyrf_branch_stack *pstack)
+{
+	free(pstack->entries);
+	Py_TYPE(pstack)->tp_free((PyObject *)pstack);
+}
+
+static Py_ssize_t pyrf_branch_stack__length(PyObject *obj)
+{
+	struct pyrf_branch_stack *pstack = (void *)obj;
+
+	return pstack->nr;
+}
+
+static PyObject *pyrf_branch_stack__item(PyObject *obj, Py_ssize_t i)
+{
+	struct pyrf_branch_stack *pstack = (void *)obj;
+	struct pyrf_branch_entry *pentry;
+
+	if (i < 0 || i >= (Py_ssize_t)pstack->nr) {
+		PyErr_SetString(PyExc_IndexError, "Index out of range");
+		return NULL;
+	}
+
+	pentry = PyObject_New(struct pyrf_branch_entry, &pyrf_branch_entry__type);
+	if (!pentry)
+		return NULL;
+
+	pentry->from = pstack->entries[i].from;
+	pentry->to = pstack->entries[i].to;
+	pentry->flags = pstack->entries[i].flags;
+
+	return (PyObject *)pentry;
+}
+
+static PySequenceMethods pyrf_branch_stack__sequence_methods = {
+	.sq_length = pyrf_branch_stack__length,
+	.sq_item   = pyrf_branch_stack__item,
+};
+
+static PyTypeObject pyrf_branch_stack__type = {
+	PyVarObject_HEAD_INIT(NULL, 0)
+	.tp_name	= "perf.branch_stack",
+	.tp_basicsize	= sizeof(struct pyrf_branch_stack),
+	.tp_dealloc	= (destructor)pyrf_branch_stack__delete,
+	.tp_flags	= Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE,
+	.tp_doc		= "perf branch stack object.",
+	.tp_as_sequence	= &pyrf_branch_stack__sequence_methods,
+};
+
+static PyObject *pyrf_sample_event__get_brstack(PyObject *self, void *closure __maybe_unused)
+{
+	struct pyrf_event *pevent = (void *)self;
+
+	if (!pevent->brstack)
+		Py_RETURN_NONE;
+
+	Py_INCREF(pevent->brstack);
+	return pevent->brstack;
+}
+
 static PyObject*
 pyrf_sample_event__getattro(struct pyrf_event *pevent, PyObject *attr_name)
 {
@@ -1017,6 +1169,12 @@ static PyGetSetDef pyrf_sample_event__getset[] = {
 		.set = NULL,
 		.doc = "event callchain.",
 	},
+	{
+		.name = "brstack",
+		.get = pyrf_sample_event__get_brstack,
+		.set = NULL,
+		.doc = "event branch stack.",
+	},
 	{
 		.name = "raw_buf",
 		.get = (getter)pyrf_sample_event__get_raw_buf,
@@ -1198,6 +1356,12 @@ static int pyrf_event__setup_types(void)
 	err = PyType_Ready(&pyrf_callchain__type);
 	if (err < 0)
 		goto out;
+	err = PyType_Ready(&pyrf_branch_entry__type);
+	if (err < 0)
+		goto out;
+	err = PyType_Ready(&pyrf_branch_stack__type);
+	if (err < 0)
+		goto out;
 out:
 	return err;
 }
@@ -1264,6 +1428,7 @@ static PyObject *pyrf_event__new(const union perf_event *event, struct evsel *ev
 
 	perf_sample__init(&pevent->sample, /*all=*/true);
 	pevent->callchain = NULL;
+	pevent->brstack = NULL;
 	pevent->al_resolved = false;
 	addr_location__init(&pevent->al);
 
@@ -1325,6 +1490,27 @@ static PyObject *pyrf_event__new(const union perf_event *event, struct evsel *ev
 			addr_location__exit(&al);
 		}
 	}
+	if (sample->branch_stack) {
+		struct branch_stack *bs = sample->branch_stack;
+		struct branch_entry *entries = perf_sample__branch_entries(sample);
+		struct pyrf_branch_stack *pstack;
+
+		pstack = PyObject_New(struct pyrf_branch_stack, &pyrf_branch_stack__type);
+		if (!pstack) {
+			Py_DECREF(pevent);
+			return NULL;
+		}
+		pstack->nr = bs->nr;
+		pstack->entries = calloc(bs->nr, sizeof(struct branch_entry));
+		if (!pstack->entries) {
+			Py_DECREF(pstack);
+			Py_DECREF(pevent);
+			return PyErr_NoMemory();
+		}
+		memcpy(pstack->entries, entries,
+		       bs->nr * sizeof(struct branch_entry));
+		pevent->brstack = (PyObject *)pstack;
+	}
 	return (PyObject *)pevent;
 }
 
@@ -3912,6 +4098,18 @@ PyMODINIT_FUNC PyInit_perf(void)
 	Py_INCREF(&pyrf_session__type);
 	PyModule_AddObject(module, "session", (PyObject *)&pyrf_session__type);
 
+	Py_INCREF(&pyrf_branch_entry__type);
+	if (PyModule_AddObject(module, "branch_entry", (PyObject *)&pyrf_branch_entry__type) < 0) {
+		Py_DECREF(&pyrf_branch_entry__type);
+		goto error;
+	}
+
+	Py_INCREF(&pyrf_branch_stack__type);
+	if (PyModule_AddObject(module, "branch_stack", (PyObject *)&pyrf_branch_stack__type) < 0) {
+		Py_DECREF(&pyrf_branch_stack__type);
+		goto error;
+	}
+
 	dict = PyModule_GetDict(module);
 	if (dict == NULL)
 		goto error;
-- 
2.54.0.1136.gdb2ca164c4-goog