[lldb-dap] Send an Invalidated event on thread stack change.

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

Author: da-viper

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) {

lldb/tools/lldb-dap/DAP.h

@@ -460,6 +460,7 @@ struct DAP final : public DAPTransport::MessageHandler {
   /// Event threads.
   /// @{
   void EventThread();
+  void HandleThreadEvent(const lldb::SBEvent &event);
   void ProgressEventThread();
 
   std::thread event_thread;

lldb/tools/lldb-dap/EventHelper.cpp

@@ -15,6 +15,7 @@
 #include "Protocol/ProtocolRequests.h"
 #include "Protocol/ProtocolTypes.h"
 #include "lldb/API/SBFileSpec.h"
+#include "lldb/lldb-defines.h"
 #include "llvm/Support/Error.h"
 #include <utility>
 
@@ -276,11 +277,16 @@ 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)});
 }
 

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);
 

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;