[lldb-dap] Add multi-session support with shared debugger instances

lldb/include/lldb/API/SBTarget.h

@@ -44,6 +44,7 @@ class LLDB_API SBTarget {
     eBroadcastBitWatchpointChanged = (1 << 3),
     eBroadcastBitSymbolsLoaded = (1 << 4),
     eBroadcastBitSymbolsChanged = (1 << 5),
+    eBroadcastBitNewTargetCreated = (1 << 6),
   };
 
   // Constructors
@@ -365,6 +366,16 @@ class LLDB_API SBTarget {
   ///     LLDB_INVALID_GLOBALLY_UNIQUE_TARGET_ID if the target is invalid.
   lldb::user_id_t GetGloballyUniqueID() const;
 
+  /// Get the target session name for this target.
+  ///
+  /// The target session name provides a meaningful name for IDEs or tools to
+  /// display to help the user identify the origin and purpose of the target.
+  ///
+  /// \return
+  ///     The target session name for this target, or nullptr if the target is
+  ///     invalid or has no target session name.
+  const char *GetTargetSessionName() const;
+
   SBError SetLabel(const char *label);
 
   /// Architecture opcode byte size width accessor

lldb/include/lldb/Target/Target.h

@@ -537,6 +537,7 @@ class Target : public std::enable_shared_from_this<Target>,
     eBroadcastBitWatchpointChanged = (1 << 3),
     eBroadcastBitSymbolsLoaded = (1 << 4),
     eBroadcastBitSymbolsChanged = (1 << 5),
+    eBroadcastBitNewTargetCreated = (1 << 6),
   };
 
   // These two functions fill out the Broadcaster interface:
@@ -622,6 +623,30 @@ class Target : public std::enable_shared_from_this<Target>,
   ///     requirements.
   llvm::Error SetLabel(llvm::StringRef label);
 
+  /// Get the target session name for this target.
+  ///
+  /// Provides a meaningful name for IDEs or tools to display for dynamically
+  /// created targets. Defaults to "Session {ID}" based on the globally unique
+  /// ID.
+  ///
+  /// \return
+  ///     The target session name for this target.
+  const std::string &GetTargetSessionName() { return m_target_session_name; }
+
+  /// Set the target session name for this target.
+  ///
+  /// This should typically be set along with the event
+  /// eBroadcastBitNewTargetCreated. Useful for scripts or triggers that
+  /// automatically create targets and want to provide meaningful names that
+  /// IDEs or other tools can display to help users identify the origin and
+  /// purpose of each target.
+  ///
+  /// \param[in] target_session_name
+  ///     The target session name to set for this target.
+  void SetTargetSessionName(llvm::StringRef target_session_name) {
+    m_target_session_name = target_session_name.str();
+  }
+
   /// Find a binary on the system and return its Module,
   /// or return an existing Module that is already in the Target.
   ///
@@ -1663,8 +1688,11 @@ class Target : public std::enable_shared_from_this<Target>,
   bool m_is_dummy_target;
   unsigned m_next_persistent_variable_index = 0;
   lldb::user_id_t m_target_unique_id =
-      LLDB_INVALID_GLOBALLY_UNIQUE_TARGET_ID; /// The globally unique ID
+      LLDB_INVALID_GLOBALLY_UNIQUE_TARGET_ID; ///< The globally unique ID
                                               /// assigned to this target
+  std::string m_target_session_name; ///< The target session name for this
+                                     /// target, used to name debugging
+                                     /// sessions in DAP.
   /// An optional \a lldb_private::Trace object containing processor trace
   /// information of this target.
   lldb::TraceSP m_trace_sp;

lldb/packages/Python/lldbsuite/test/tools/lldb-dap/dap_server.py

@@ -785,6 +785,7 @@ def request_attach(
         *,
         program: Optional[str] = None,
         pid: Optional[int] = None,
+        targetId: Optional[int] = None,
         waitFor=False,
         initCommands: Optional[list[str]] = None,
         preRunCommands: Optional[list[str]] = None,
@@ -804,6 +805,8 @@ def request_attach(
             args_dict["pid"] = pid
         if program is not None:
             args_dict["program"] = program
+        if targetId is not None:
+            args_dict["targetId"] = targetId
         if waitFor:
             args_dict["waitFor"] = waitFor
         args_dict["initCommands"] = self.init_commands

lldb/source/API/SBTarget.cpp

@@ -1641,6 +1641,14 @@ lldb::user_id_t SBTarget::GetGloballyUniqueID() const {
   return LLDB_INVALID_GLOBALLY_UNIQUE_TARGET_ID;
 }
 
+const char *SBTarget::GetTargetSessionName() const {
+  LLDB_INSTRUMENT_VA(this);
+
+  if (TargetSP target_sp = GetSP())
+    return ConstString(target_sp->GetTargetSessionName().data()).AsCString();
+  return nullptr;
+}
+
 SBError SBTarget::SetLabel(const char *label) {
   LLDB_INSTRUMENT_VA(this, label);
 

lldb/source/Target/Target.cpp

@@ -186,13 +186,16 @@ Target::Target(Debugger &debugger, const ArchSpec &target_arch,
       m_latest_stop_hook_id(0), m_valid(true), m_suppress_stop_hooks(false),
       m_is_dummy_target(is_dummy_target),
       m_target_unique_id(g_target_unique_id++),
+      m_target_session_name(
+          llvm::formatv("Session {0}", m_target_unique_id).str()),
       m_frame_recognizer_manager_up(
           std::make_unique<StackFrameRecognizerManager>()) {
   SetEventName(eBroadcastBitBreakpointChanged, "breakpoint-changed");
   SetEventName(eBroadcastBitModulesLoaded, "modules-loaded");
   SetEventName(eBroadcastBitModulesUnloaded, "modules-unloaded");
   SetEventName(eBroadcastBitWatchpointChanged, "watchpoint-changed");
   SetEventName(eBroadcastBitSymbolsLoaded, "symbols-loaded");
+  SetEventName(eBroadcastBitNewTargetCreated, "new-target-created");
 
   CheckInWithManager();
 

lldb/test/API/tools/lldb-dap/attach/TestDAP_attach.py

@@ -72,3 +72,14 @@ def test_by_name_waitFor(self):
         self.spawn_thread.start()
         self.attach(program=program, waitFor=True)
         self.continue_and_verify_pid()
+
+    def test_attach_with_invalid_targetId(self):
+        """
+        Test that attaching with an invalid targetId fails with the expected
+        error message.
+        """
+        self.build_and_create_debug_adapter()
+
+        resp = self.attach(targetId=99999, expectFailure=True)
+        self.assertFalse(resp["success"])
+        self.assertIn("Unable to find existing target", resp["body"]["error"]["format"])

lldb/tools/lldb-dap/CMakeLists.txt

@@ -12,6 +12,7 @@ add_lldb_library(lldbDAP
   DAP.cpp
   DAPError.cpp
   DAPLog.cpp
+  DAPSessionManager.cpp
   EventHelper.cpp
   ExceptionBreakpoint.cpp
   FifoFiles.cpp