[lldb] add support for thread names on Windows (llvm#74731)

This PR adds support for thread names in lldb on Windows.

```
(lldb) thr list
Process 2960 stopped
  thread llvm#53: tid = 0x03a0, 0x00007ff84582db34 ntdll.dll`NtWaitForMultipleObjects + 20
  thread llvm#29: tid = 0x04ec, 0x00007ff845830a14 ntdll.dll`NtWaitForAlertByThreadId + 20, name = 'SPUW.6'
  thread llvm#89: tid = 0x057c, 0x00007ff845830a14 ntdll.dll`NtWaitForAlertByThreadId + 20, name = 'PPU[0x1000019] physics[main]'
  thread #3: tid = 0x0648, 0x00007ff843c2cafe combase.dll`InternalDoATClassCreate + 39518
  thread llvm#93: tid = 0x0688, 0x00007ff845830a14 ntdll.dll`NtWaitForAlertByThreadId + 20, name = 'PPU[0x100501d] uMovie::StreamingThread'
  thread #1: tid = 0x087c, 0x00007ff842e7a104 win32u.dll`NtUserMsgWaitForMultipleObjectsEx + 20
  thread llvm#96: tid = 0x0890, 0x00007ff845830a14 ntdll.dll`NtWaitForAlertByThreadId + 20, name = 'PPU[0x1002020] HLE Video Decoder'
<...>
```

lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.cpp

@@ -7,18 +7,14 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/HostInfo.h"
-#include "lldb/Host/HostNativeThreadBase.h"
-#include "lldb/Host/windows/HostThreadWindows.h"
-#include "lldb/Host/windows/windows.h"
-#include "lldb/Target/RegisterContext.h"
 #include "lldb/Target/Unwind.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
-#include "lldb/Utility/State.h"
 
 #include "ProcessWindows.h"
-#include "ProcessWindowsLog.h"
 #include "TargetThreadWindows.h"
+#include "lldb/Host/windows/HostThreadWindows.h"
+#include <llvm/Support/ConvertUTF.h>
 
 #if defined(__x86_64__) || defined(_M_AMD64)
 #include "x64/RegisterContextWindows_x64.h"
@@ -33,6 +29,9 @@
 using namespace lldb;
 using namespace lldb_private;
 
+using GetThreadDescriptionFunctionPtr = HRESULT
+WINAPI (*)(HANDLE hThread, PWSTR *ppszThreadDescription);
+
 TargetThreadWindows::TargetThreadWindows(ProcessWindows &process,
                                          const HostThread &thread)
     : Thread(process, thread.GetNativeThread().GetThreadId()),
@@ -175,3 +174,29 @@ Status TargetThreadWindows::DoResume() {
 
   return Status();
 }
+
+const char *TargetThreadWindows::GetName() {
+  Log *log = GetLog(LLDBLog::Thread);
+  static GetThreadDescriptionFunctionPtr GetThreadDescription = []() {
+    HMODULE hModule = ::LoadLibraryW(L"Kernel32.dll");
+    return hModule ? reinterpret_cast<GetThreadDescriptionFunctionPtr>(
+                         ::GetProcAddress(hModule, "GetThreadDescription"))
+                   : nullptr;
+  }();
+  LLDB_LOGF(log, "GetProcAddress: %p",
+            reinterpret_cast<void *>(GetThreadDescription));
+  if (!GetThreadDescription)
+    return m_name.c_str();
+  PWSTR pszThreadName;
+  if (SUCCEEDED(GetThreadDescription(
+          m_host_thread.GetNativeThread().GetSystemHandle(), &pszThreadName))) {
+    LLDB_LOGF(log, "GetThreadDescription: %ls", pszThreadName);
+    llvm::convertUTF16ToUTF8String(
+        llvm::ArrayRef(reinterpret_cast<char *>(pszThreadName),
+                       wcslen(pszThreadName) * sizeof(wchar_t)),
+        m_name);
+    ::LocalFree(pszThreadName);
+  }
+
+  return m_name.c_str();
+}

lldb/source/Plugins/Process/Windows/Common/TargetThreadWindows.h

@@ -34,6 +34,7 @@ class TargetThreadWindows : public lldb_private::Thread {
   lldb::RegisterContextSP
   CreateRegisterContextForFrame(StackFrame *frame) override;
   bool CalculateStopInfo() override;
+  const char *GetName() override;
 
   Status DoResume();
 
@@ -42,6 +43,7 @@ class TargetThreadWindows : public lldb_private::Thread {
 private:
   lldb::RegisterContextSP m_thread_reg_ctx_sp;
   HostThread m_host_thread;
+  std::string m_name;
 };
 } // namespace lldb_private
 

lldb/unittests/Thread/CMakeLists.txt

@@ -11,5 +11,7 @@ add_lldb_unittest(ThreadTests
       lldbInterpreter
       lldbBreakpoint
       lldbPluginPlatformLinux
+      lldbPluginPlatformWindows
+      lldbPluginProcessWindowsCommon
   )
 

lldb/unittests/Thread/ThreadTest.cpp

@@ -8,9 +8,20 @@
 
 #include "lldb/Target/Thread.h"
 #include "Plugins/Platform/Linux/PlatformLinux.h"
+#include <thread>
+#ifdef _WIN32
+#include "lldb/Host/windows/HostThreadWindows.h"
+#include "lldb/Host/windows/windows.h"
+
+#include "Plugins/Platform/Windows/PlatformWindows.h"
+#include "Plugins/Process/Windows/Common/LocalDebugDelegate.h"
+#include "Plugins/Process/Windows/Common/ProcessWindows.h"
+#include "Plugins/Process/Windows/Common/TargetThreadWindows.h"
+#endif
 #include "lldb/Core/Debugger.h"
 #include "lldb/Host/FileSystem.h"
 #include "lldb/Host/HostInfo.h"
+#include "lldb/Host/HostThread.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/StopInfo.h"
 #include "lldb/Utility/ArchSpec.h"
@@ -21,14 +32,33 @@ using namespace lldb_private::repro;
 using namespace lldb;
 
 namespace {
+
+#ifdef _WIN32
+using SetThreadDescriptionFunctionPtr = HRESULT
+WINAPI (*)(HANDLE hThread, PCWSTR lpThreadDescription);
+
+static SetThreadDescriptionFunctionPtr SetThreadName;
+#endif
+
 class ThreadTest : public ::testing::Test {
 public:
   void SetUp() override {
     FileSystem::Initialize();
     HostInfo::Initialize();
+#ifdef _WIN32
+    HMODULE hModule = ::LoadLibraryW(L"Kernel32.dll");
+    if (hModule) {
+      SetThreadName = reinterpret_cast<SetThreadDescriptionFunctionPtr>(
+          ::GetProcAddress(hModule, "SetThreadDescription"));
+    }
+    PlatformWindows::Initialize();
+#endif
     platform_linux::PlatformLinux::Initialize();
   }
   void TearDown() override {
+#ifdef _WIN32
+    PlatformWindows::Terminate();
+#endif
     platform_linux::PlatformLinux::Terminate();
     HostInfo::Terminate();
     FileSystem::Terminate();
@@ -88,6 +118,47 @@ TargetSP CreateTarget(DebuggerSP &debugger_sp, ArchSpec &arch) {
   return target_sp;
 }
 
+#ifdef _WIN32
+std::shared_ptr<TargetThreadWindows>
+CreateWindowsThread(const ProcessWindowsSP &process_sp, std::thread &t) {
+  HostThread host_thread((lldb::thread_t)t.native_handle());
+  ThreadSP thread_sp =
+      std::make_shared<TargetThreadWindows>(*process_sp.get(), host_thread);
+  return std::static_pointer_cast<TargetThreadWindows>(thread_sp);
+}
+
+TEST_F(ThreadTest, GetThreadDescription) {
+  if (!SetThreadName)
+    return;
+
+  ArchSpec arch(HostInfo::GetArchitecture());
+  Platform::SetHostPlatform(PlatformWindows::CreateInstance(true, &arch));
+
+  DebuggerSP debugger_sp = Debugger::CreateInstance();
+  ASSERT_TRUE(debugger_sp);
+
+  TargetSP target_sp = CreateTarget(debugger_sp, arch);
+  ASSERT_TRUE(target_sp);
+
+  ListenerSP listener_sp(Listener::MakeListener("dummy"));
+  auto process_sp = std::static_pointer_cast<ProcessWindows>(
+      ProcessWindows::CreateInstance(target_sp, listener_sp, nullptr, false));
+  ASSERT_TRUE(process_sp);
+
+  std::thread t([]() {});
+  auto thread_sp = CreateWindowsThread(process_sp, t);
+  DWORD tid = thread_sp->GetHostThread().GetNativeThread().GetThreadId();
+  HANDLE hThread = ::OpenThread(THREAD_SET_LIMITED_INFORMATION, FALSE, tid);
+  ASSERT_TRUE(hThread);
+
+  SetThreadName(hThread, L"thread name");
+  ::CloseHandle(hThread);
+  ASSERT_STREQ(thread_sp->GetName(), "thread name");
+
+  t.join();
+}
+#endif
+
 TEST_F(ThreadTest, SetStopInfo) {
   ArchSpec arch("powerpc64-pc-linux");