[lldb-dap] Send an Invalidated event on thread stack change. (#163976)

When the user send `thread return <expr>` command this changes the stack
length but the UI does not update.
Send stack invalidated event to the client to update the stack.

10 files changed, 119 insertions, 11 deletions

diff --git a/lldb/test/API/tools/lldb-dap/invalidated-event/Makefile b/lldb/test/API/tools/lldb-dap/invalidated-event/Makefile
new file mode 100644
index 000000000000..99998b20bcb0
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/invalidated-event/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/tools/lldb-dap/invalidated-event/TestDAP_invalidatedEvent.py b/lldb/test/API/tools/lldb-dap/invalidated-event/TestDAP_invalidatedEvent.py
new file mode 100644
index 000000000000..8ba56b0bb27c
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/invalidated-event/TestDAP_invalidatedEvent.py
@@ -0,0 +1,55 @@
+"""
+Test lldb-dap recieves invalidated-events when the area such as
+stack, variables, threads has changes but the client does not
+know about it.
+"""
+
+import lldbdap_testcase
+from lldbsuite.test.lldbtest import line_number
+from dap_server import Event
+
+
+class TestDAP_invalidatedEvent(lldbdap_testcase.DAPTestCaseBase):
+    def verify_top_frame_name(self, frame_name: str):
+        all_frames = self.get_stackFrames()
+        self.assertGreaterEqual(len(all_frames), 1, "Expected at least one frame.")
+        top_frame_name = all_frames[0]["name"]
+        self.assertRegex(top_frame_name, f"{frame_name}.*")
+
+    def test_invalidated_stack_area_event(self):
+        """
+        Test an invalidated event for the stack area.
+        The event is sent when the command `thread return <expr>` is sent by the user.
+        """
+        other_source = "other.h"
+        return_bp_line = line_number(other_source, "// thread return breakpoint")
+
+        program = self.getBuildArtifact("a.out")
+        self.build_and_launch(program)
+        self.set_source_breakpoints(other_source, [return_bp_line])
+        self.continue_to_next_stop()
+
+        self.verify_top_frame_name("add")
+        thread_id = self.dap_server.get_thread_id()
+        self.assertIsNotNone(thread_id, "Exepected a thread id.")
+
+        # run thread return
+        thread_command = "thread return 20"
+        eval_resp = self.dap_server.request_evaluate(thread_command, context="repl")
+        self.assertTrue(eval_resp["success"], f"Failed to evaluate `{thread_command}`.")
+
+        # wait for the invalidated stack event.
+        stack_event = self.dap_server.wait_for_event(["invalidated"])
+        self.assertIsNotNone(stack_event, "Expected an invalidated event.")
+        event_body: Event = stack_event["body"]
+        self.assertIn("stacks", event_body["areas"])
+        self.assertIn("threadId", event_body.keys())
+        self.assertEqual(
+            thread_id,
+            event_body["threadId"],
+            f"Expected the event from thread {thread_id}.",
+        )
+
+        # confirm we are back at the main frame.
+        self.verify_top_frame_name("main")
+        self.continue_to_exit()
diff --git a/lldb/test/API/tools/lldb-dap/invalidated-event/main.cpp b/lldb/test/API/tools/lldb-dap/invalidated-event/main.cpp
new file mode 100644
index 000000000000..c82f9532b751
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/invalidated-event/main.cpp
@@ -0,0 +1,9 @@
+#include "other.h"
+
+int main() {
+  int first = 5;
+  int second = 10;
+  const int result = add(first, second);
+
+  return 0;
+}
diff --git a/lldb/test/API/tools/lldb-dap/invalidated-event/other.h b/lldb/test/API/tools/lldb-dap/invalidated-event/other.h
new file mode 100644
index 000000000000..856db446d7b5
--- /dev/null
+++ b/lldb/test/API/tools/lldb-dap/invalidated-event/other.h
@@ -0,0 +1,10 @@
+#ifndef OTHER_H
+#define OTHER_H
+
+int add(int a, int b) {
+  int first = a;
+  int second = b; // thread return breakpoint
+  int result = first + second;
+  return result;
+}
+#endif // OTHER_H
diff --git a/lldb/tools/lldb-dap/DAP.cpp b/lldb/tools/lldb-dap/DAP.cpp
index f76656e98ca0..61226cceb6db 100644
--- a/lldb/tools/lldb-dap/DAP.cpp
+++ b/lldb/tools/lldb-dap/DAP.cpp
@@ -1368,6 +1368,12 @@ void DAP::EventThread() {
   broadcaster.AddListener(listener, eBroadcastBitStopEventThread);
   debugger.GetBroadcaster().AddListener(
       listener, lldb::eBroadcastBitError | lldb::eBroadcastBitWarning);
+
+  // listen for thread events.
+  listener.StartListeningForEventClass(
+      debugger, lldb::SBThread::GetBroadcasterClassName(),
+      lldb::SBThread::eBroadcastBitStackChanged);
+
   bool done = false;
   while (!done) {
     if (listener.WaitForEvent(1, event)) {
@@ -1503,6 +1509,9 @@ void DAP::EventThread() {
             SendJSON(llvm::json::Value(std::move(bp_event)));
           }
         }
+
+      } else if (lldb::SBThread::EventIsThreadEvent(event)) {
+        HandleThreadEvent(event);
       } else if (event_mask & lldb::eBroadcastBitError ||
                  event_mask & lldb::eBroadcastBitWarning) {
         lldb::SBStructuredData data =
@@ -1522,6 +1531,16 @@ void DAP::EventThread() {
   }
 }
 
+void DAP::HandleThreadEvent(const lldb::SBEvent &event) {
+  uint32_t event_type = event.GetType();
+
+  if (event_type & lldb::SBThread::eBroadcastBitStackChanged) {
+    const lldb::SBThread evt_thread = lldb::SBThread::GetThreadFromEvent(event);
+    SendInvalidatedEvent(*this, {InvalidatedEventBody::eAreaStacks},
+                         evt_thread.GetThreadID());
+  }
+}
+
 std::vector<protocol::Breakpoint> DAP::SetSourceBreakpoints(
     const protocol::Source &source,
     const std::optional<std::vector<protocol::SourceBreakpoint>> &breakpoints) {
diff --git a/lldb/tools/lldb-dap/DAP.h b/lldb/tools/lldb-dap/DAP.h
index a90ddf59671e..bf2c3f146a39 100644
--- a/lldb/tools/lldb-dap/DAP.h
+++ b/lldb/tools/lldb-dap/DAP.h
@@ -460,6 +460,7 @@ private:
   /// Event threads.
   /// @{
   void EventThread();
+  void HandleThreadEvent(const lldb::SBEvent &event);
   void ProgressEventThread();
 
   std::thread event_thread;
diff --git a/lldb/tools/lldb-dap/EventHelper.cpp b/lldb/tools/lldb-dap/EventHelper.cpp
index 2b9ed229405a..3042d3293b48 100644
--- a/lldb/tools/lldb-dap/EventHelper.cpp
+++ b/lldb/tools/lldb-dap/EventHelper.cpp
@@ -276,11 +276,16 @@ void SendProcessExitedEvent(DAP &dap, lldb::SBProcess &process) {
 }
 
 void SendInvalidatedEvent(
-    DAP &dap, llvm::ArrayRef<protocol::InvalidatedEventBody::Area> areas) {
+    DAP &dap, llvm::ArrayRef<protocol::InvalidatedEventBody::Area> areas,
+    lldb::tid_t tid) {
   if (!dap.clientFeatures.contains(protocol::eClientFeatureInvalidatedEvent))
     return;
   protocol::InvalidatedEventBody body;
   body.areas = areas;
+
+  if (tid != LLDB_INVALID_THREAD_ID)
+    body.threadId = tid;
+
   dap.Send(protocol::Event{"invalidated", std::move(body)});
 }
 
diff --git a/lldb/tools/lldb-dap/EventHelper.h b/lldb/tools/lldb-dap/EventHelper.h
index 48eb5af6bd0b..be783d032a5a 100644
--- a/lldb/tools/lldb-dap/EventHelper.h
+++ b/lldb/tools/lldb-dap/EventHelper.h
@@ -11,6 +11,8 @@
 
 #include "DAPForward.h"
 #include "Protocol/ProtocolEvents.h"
+#include "lldb/lldb-defines.h"
+#include "lldb/lldb-types.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Support/Error.h"
 
@@ -35,7 +37,8 @@ void SendContinuedEvent(DAP &dap);
 void SendProcessExitedEvent(DAP &dap, lldb::SBProcess &process);
 
 void SendInvalidatedEvent(
-    DAP &dap, llvm::ArrayRef<protocol::InvalidatedEventBody::Area> areas);
+    DAP &dap, llvm::ArrayRef<protocol::InvalidatedEventBody::Area> areas,
+    lldb::tid_t tid = LLDB_INVALID_THREAD_ID);
 
 void SendMemoryEvent(DAP &dap, lldb::SBValue variable);
 
diff --git a/lldb/tools/lldb-dap/Protocol/ProtocolEvents.cpp b/lldb/tools/lldb-dap/Protocol/ProtocolEvents.cpp
index b896eca817be..df6be06637a1 100644
--- a/lldb/tools/lldb-dap/Protocol/ProtocolEvents.cpp
+++ b/lldb/tools/lldb-dap/Protocol/ProtocolEvents.cpp
@@ -51,7 +51,7 @@ llvm::json::Value toJSON(const InvalidatedEventBody::Area &IEBA) {
 llvm::json::Value toJSON(const InvalidatedEventBody &IEB) {
   json::Object Result{{"areas", IEB.areas}};
   if (IEB.threadId)
-    Result.insert({"threadID", IEB.threadId});
+    Result.insert({"threadId", IEB.threadId});
   if (IEB.stackFrameId)
     Result.insert({"stackFrameId", IEB.stackFrameId});
   return Result;
diff --git a/lldb/unittests/DAP/ProtocolTypesTest.cpp b/lldb/unittests/DAP/ProtocolTypesTest.cpp
index a5ae856a185b..8170abdd25bc 100644
--- a/lldb/unittests/DAP/ProtocolTypesTest.cpp
+++ b/lldb/unittests/DAP/ProtocolTypesTest.cpp
@@ -1079,14 +1079,17 @@ TEST(ProtocolTypesTest, InvalidatedEventBody) {
   body.areas = {InvalidatedEventBody::eAreaStacks,
                 InvalidatedEventBody::eAreaThreads};
   body.stackFrameId = 1;
-  StringRef json = R"({
-  "areas": [
-    "stacks",
-    "threads"
-  ],
-  "stackFrameId": 1
-})";
-  EXPECT_EQ(json, pp(body));
+  body.threadId = 20;
+  Expected<json::Value> expected = json::parse(R"({
+    "areas": [
+      "stacks",
+      "threads"
+    ],
+    "stackFrameId": 1,
+    "threadId": 20
+    })");
+  ASSERT_THAT_EXPECTED(expected, llvm::Succeeded());
+  EXPECT_EQ(pp(*expected), pp(body));
 }
 
 TEST(ProtocolTypesTest, MemoryEventBody) {