[lldb][swift] Add test demonstrating how step out fails

Author: felipepiovezan

lldb/test/API/lang/swift/async/stepping/step_out/Makefile

@@ -0,0 +1,3 @@
+SWIFT_SOURCES := main.swift
+SWIFTFLAGS_EXTRAS := -parse-as-library
+include Makefile.rules

lldb/test/API/lang/swift/async/stepping/step_out/TestSteppingOutAsync.py

@@ -0,0 +1,44 @@
+import lldb
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbtest as lldbtest
+import lldbsuite.test.lldbutil as lldbutil
+import re
+
+
+class TestCase(lldbtest.TestBase):
+
+    def check_and_get_frame_names(self, process):
+        frames = process.GetSelectedThread().frames
+        # Expected frames:
+        # ASYNC___0___ <- ASYNC___1___ <- ASYNC___2___ <- ASYNC___3___ <- Main
+        num_frames = 5
+        func_names = [frame.GetFunctionName() for frame in frames[:num_frames]]
+        for idx in range(num_frames - 1):
+            self.assertIn(f"ASYNC___{idx}___", func_names[idx])
+        self.assertIn("Main", func_names[num_frames - 1])
+        return func_names
+
+    def step_out_checks(self, thread, expected_func_names):
+        # Keep stepping out, comparing the top frame's name with the expected name.
+        for expected_func_name in expected_func_names:
+            error = lldb.SBError()
+            thread.StepOut(error)
+            self.assertSuccess(error, "step out failed")
+            stop_reason = thread.GetStopReason()
+            self.assertStopReason(stop_reason, lldb.eStopReasonPlanComplete)
+            self.assertEqual(thread.frames[0].GetFunctionName(), expected_func_name)
+
+    @swiftTest
+    @skipIf(oslist=["windows", "linux"])
+    @skipIf("rdar://133849022")
+    def test(self):
+        """Test `frame variable` in async functions"""
+        self.build()
+
+        source_file = lldb.SBFileSpec("main.swift")
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, "BREAK HERE", source_file
+        )
+
+        func_names = self.check_and_get_frame_names(process)
+        self.step_out_checks(thread, func_names[1:])

lldb/test/API/lang/swift/async/stepping/step_out/main.swift

@@ -0,0 +1,38 @@
+func work() {
+  print("working")
+}
+
+func ASYNC___0___() async -> Int {
+  var myvar = 111;
+  work()
+  myvar += 1; // BREAK HERE
+  return myvar
+}
+
+func ASYNC___1___() async -> Int {
+  var blah = 333
+  work()
+  var result = await ASYNC___0___()
+  work()
+  return result + blah
+}
+
+func ASYNC___2___() async -> Int {
+  work()
+  var result1 = await ASYNC___1___()
+  work()
+  return result1
+}
+
+func ASYNC___3___() async -> Int {
+  var result = await ASYNC___2___()
+  work()
+  return result
+}
+
+@main struct Main {
+  static func main() async {
+    let result = await ASYNC___3___()
+    print(result)
+  }
+}