Strengthen JIT unwind tests

Author: diegorusso

Lib/test/test_frame_pointer_unwind.py

@@ -17,6 +17,9 @@
     raise unittest.SkipTest("test requires subprocess support")
 
 
+STACK_DEPTH = 10
+
+
 def _frame_pointers_expected(machine):
     cflags = " ".join(
         value for value in (
@@ -89,7 +92,7 @@ def build_stack(n, unwinder, warming_up_caller=False):
             result = operator.call(build_stack, n - 1, unwinder, warming_up)
         return result
 
-    stack = build_stack(10, unwinder)
+    stack = build_stack(STACK_DEPTH, unwinder)
     return stack
 
 
@@ -112,9 +115,7 @@ def _classify_stack(stack, jit_enabled):
     return annotated, python_frames, jit_frames, other_frames
 
 
-def _annotate_unwind(unwinder_name="manual_frame_pointer_unwind"):
-    unwinder = getattr(_testinternalcapi, unwinder_name)
-    stack = _build_stack_and_unwind(unwinder)
+def _summarize_unwind(stack, unwinder_name):
     jit_enabled = hasattr(sys, "_jit") and sys._jit.is_enabled()
     jit_backend = _testinternalcapi.get_jit_backend()
     ranges = _testinternalcapi.get_jit_code_ranges() if jit_enabled else []
@@ -127,20 +128,44 @@ def _annotate_unwind(unwinder_name="manual_frame_pointer_unwind"):
     )
     for idx, addr, tag in annotated:
         print(f"#{idx:02d} {addr:#x} -> {tag}")
-    return json.dumps({
+    return {
         "length": len(stack),
         "python_frames": python_frames,
         "jit_frames": jit_frames,
         "other_frames": other_frames,
         "jit_backend": jit_backend,
         "unwinder": unwinder_name,
+    }
+
+
+def _annotate_unwind(unwinder_name="manual_frame_pointer_unwind"):
+    unwinder = getattr(_testinternalcapi, unwinder_name)
+    stack = _build_stack_and_unwind(unwinder)
+    return json.dumps(_summarize_unwind(stack, unwinder_name))
+
+
+def _annotate_unwind_after_executor_free(unwinder_name="gnu_backtrace_unwind"):
+    # The first unwind runs at the bottom of _build_stack_and_unwind(), while
+    # the recursive helper may be executing in JIT code. After it returns, this
+    # helper is back in normal test code; clearing executor caches should remove
+    # the old JIT ranges, so the second unwind must not report stale JIT frames.
+    live = json.loads(_annotate_unwind(unwinder_name))
+
+    sys._clear_internal_caches()
+    _testinternalcapi.clear_executor_deletion_list()
+
+    unwinder = getattr(_testinternalcapi, unwinder_name)
+    after_free = _summarize_unwind(unwinder(), unwinder_name)
+    return json.dumps({
+        "live": live,
+        "after_free": after_free,
     })
 
 
-def _unwind_result(unwinder_name, **env):
+def _run_unwind_helper(helper_name, unwinder_name, **env):
     code = (
-        "from test.test_frame_pointer_unwind import _annotate_unwind; "
-        f"print(_annotate_unwind({unwinder_name!r}));"
+        f"from test.test_frame_pointer_unwind import {helper_name}; "
+        f"print({helper_name}({unwinder_name!r}));"
     )
     run_env = os.environ.copy()
     run_env.update(env)
@@ -168,6 +193,15 @@ def _unwind_result(unwinder_name, **env):
         ) from exc
 
 
+def _unwind_result(unwinder_name, **env):
+    return _run_unwind_helper("_annotate_unwind", unwinder_name, **env)
+
+
+def _unwind_after_executor_free_result(unwinder_name, **env):
+    return _run_unwind_helper(
+        "_annotate_unwind_after_executor_free", unwinder_name, **env)
+
+
 @support.requires_gil_enabled("test requires the GIL enabled")
 @unittest.skipIf(support.is_wasi, "test not supported on WASI")
 class FramePointerUnwindTests(unittest.TestCase):
@@ -204,9 +238,9 @@ def test_manual_unwind_respects_frame_pointers(self):
                 python_frames = result.get("python_frames", 0)
                 jit_backend = result.get("jit_backend")
                 if self.frame_pointers_expected:
-                    self.assertGreater(
+                    self.assertGreaterEqual(
                         python_frames,
-                        0,
+                        STACK_DEPTH,
                         f"expected to find Python frames on {self.machine} with env {env}",
                     )
                     if using_jit:
@@ -269,9 +303,9 @@ def test_gnu_backtrace_unwinds_through_jit_frames(self):
                 jit_frames = result.get("jit_frames", 0)
                 jit_backend = result.get("jit_backend")
 
-                self.assertGreater(
+                self.assertGreaterEqual(
                     python_frames,
-                    0,
+                    STACK_DEPTH,
                     f"expected to find Python frames in GNU backtrace with env {env}",
                 )
                 if using_jit and jit_backend == "jit":
@@ -287,6 +321,39 @@ def test_gnu_backtrace_unwinds_through_jit_frames(self):
                         f"unexpected JIT frames counted in GNU backtrace with env {env}",
                     )
 
+    def test_gnu_backtrace_jit_frames_disappear_after_executor_free(self):
+        if not (hasattr(sys, "_jit") and sys._jit.is_available()):
+            self.skipTest("JIT is not available")
+
+        result = _unwind_after_executor_free_result(
+            "gnu_backtrace_unwind", PYTHON_JIT="1")
+        live = result["live"]
+        if live.get("jit_backend") != "jit":
+            self.skipTest("JIT backend is not active")
+
+        self.assertGreaterEqual(
+            live.get("python_frames", 0),
+            STACK_DEPTH,
+            "expected live GNU backtrace to include recursive Python frames",
+        )
+        self.assertGreater(
+            live.get("jit_frames", 0),
+            0,
+            "expected live GNU backtrace to include JIT frames",
+        )
+
+        after_free = result["after_free"]
+        self.assertGreater(
+            after_free.get("python_frames", 0),
+            0,
+            "expected GNU backtrace after executor free to include Python frames",
+        )
+        self.assertEqual(
+            after_free.get("jit_frames", 0),
+            0,
+            "unexpected JIT frames in GNU backtrace after executor free",
+        )
+
 
 if __name__ == "__main__":
     unittest.main()