[Lldb-commits] [lldb] [lldb-dap] Stop the process for the threads request (PR #134456)

[Jonas Devlieghere via lldb-commits]

https://github.com/JDevlieghere created https://github.com/llvm/llvm-project/pull/134456

None

>From 621a5f78b72232e3f76dc2c6162bffc8051045ae Mon Sep 17 00:00:00 2001
From: Jonas Devlieghere <jonas at devlieghere.com>
Date: Fri, 4 Apr 2025 15:07:21 -0700
Subject: [PATCH] [lldb-dap] Stop the process for the threads request

---
 .../Handler/ThreadsRequestHandler.cpp         | 24 +++++++++++++++++--
 lldb/tools/lldb-dap/JSONUtils.cpp             |  9 +++++++
 lldb/tools/lldb-dap/JSONUtils.h               | 10 ++++++++
 3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/lldb/tools/lldb-dap/Handler/ThreadsRequestHandler.cpp b/lldb/tools/lldb-dap/Handler/ThreadsRequestHandler.cpp
index 2b857f7f6a02b..61d6fb286e261 100644
--- a/lldb/tools/lldb-dap/Handler/ThreadsRequestHandler.cpp
+++ b/lldb/tools/lldb-dap/Handler/ThreadsRequestHandler.cpp
@@ -10,6 +10,7 @@
 #include "EventHelper.h"
 #include "JSONUtils.h"
 #include "RequestHandler.h"
+#include "lldb/API/SBError.h"
 
 namespace lldb_dap {
 
@@ -54,15 +55,34 @@ void ThreadsRequestHandler::operator()(
   llvm::json::Object response;
   FillResponse(request, response);
 
+  const auto state = process.GetState();
+  const bool stop_and_resume =
+      state != lldb::eStateCrashed && state != lldb::eStateStopped;
+
+  if (stop_and_resume) {
+    lldb::SBError error = dap.WaitForProcessToStop(1);
+    if (error.Fail()) {
+      SetError(response, error);
+      dap.SendJSON(llvm::json::Value(std::move(response)));
+    }
+  }
+
   const uint32_t num_threads = process.GetNumThreads();
   llvm::json::Array threads;
   for (uint32_t thread_idx = 0; thread_idx < num_threads; ++thread_idx) {
     lldb::SBThread thread = process.GetThreadAtIndex(thread_idx);
     threads.emplace_back(CreateThread(thread, dap.thread_format));
   }
-  if (threads.size() == 0) {
-    response["success"] = llvm::json::Value(false);
+
+  if (stop_and_resume) {
+    lldb::SBError error = process.Continue();
+    if (error.Fail()) {
+      SetError(response, error);
+      dap.SendJSON(llvm::json::Value(std::move(response)));
+    }
   }
+
+  response["success"] = llvm::json::Value(threads.size() != 0);
   llvm::json::Object body;
   body.try_emplace("threads", std::move(threads));
   response.try_emplace("body", std::move(body));
diff --git a/lldb/tools/lldb-dap/JSONUtils.cpp b/lldb/tools/lldb-dap/JSONUtils.cpp
index 7660403666150..17b9e343a48fa 100644
--- a/lldb/tools/lldb-dap/JSONUtils.cpp
+++ b/lldb/tools/lldb-dap/JSONUtils.cpp
@@ -268,6 +268,15 @@ void FillResponse(const llvm::json::Object &request,
   response.try_emplace("success", true);
 }
 
+void SetError(llvm::json::Object &response, lldb::SBError error) {
+  assert(error.Fail());
+
+  response["success"] = llvm::json::Value(error.Success());
+  const char *error_cstr = error.GetCString();
+  if (error_cstr && error_cstr[0])
+    EmplaceSafeString(response, "message", std::string(error_cstr));
+}
+
 // "Scope": {
 //   "type": "object",
 //   "description": "A Scope is a named container for variables. Optionally
diff --git a/lldb/tools/lldb-dap/JSONUtils.h b/lldb/tools/lldb-dap/JSONUtils.h
index da91797290ff0..e9cd75e884896 100644
--- a/lldb/tools/lldb-dap/JSONUtils.h
+++ b/lldb/tools/lldb-dap/JSONUtils.h
@@ -12,6 +12,7 @@
 #include "DAPForward.h"
 #include "Protocol/ProtocolTypes.h"
 #include "lldb/API/SBCompileUnit.h"
+#include "lldb/API/SBError.h"
 #include "lldb/API/SBFileSpec.h"
 #include "lldb/API/SBFormat.h"
 #include "lldb/API/SBLineEntry.h"
@@ -197,6 +198,15 @@ GetStringMap(const llvm::json::Object &obj, llvm::StringRef key);
 void FillResponse(const llvm::json::Object &request,
                   llvm::json::Object &response);
 
+/// Set the response to failed and populate the message if there is one.
+///
+/// \param[in,out] response
+///     An llvm::json::Object object that will be populated.
+///
+/// \param[in] error
+///     A LLDB error in the failed state.
+void SetError(llvm::json::Object &response, lldb::SBError error);
+
 /// Converts \a bp to a JSON value and appends the first valid location to the
 /// \a breakpoints array.
 ///