Author: Nerixyz Date: 2026-05-11T12:49:01+02:00 New Revision: c1056d17e1208d5bd96cb7eb1f4a369f559625ac
URL: https://github.com/llvm/llvm-project/commit/c1056d17e1208d5bd96cb7eb1f4a369f559625ac DIFF: https://github.com/llvm/llvm-project/commit/c1056d17e1208d5bd96cb7eb1f4a369f559625ac.diff LOG: [lldb][Windows] Use WaitForDebugEventEx if available (#196817) This makes use of [`WaitForDebugEventEx`](https://learn.microsoft.com/en-us/windows/win32/api/debugapi/nf-debugapi-waitfordebugeventex) over `WaitForDebugEvent` if available (Windows 10+). The two functions are identical except for the handling of `OutputDebugStringW`. The `-Ex` version forwards the string as Unicode whereas the other version forwards ASCII strings. Since we don't handle these outputs yet, it shouldn't make any difference. Split from #196395. Added: Modified: lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp Removed: ################################################################################ diff --git a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp index 6359a63dfef91..8c35a2b9262cc 100644 --- a/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/DebuggerThread.cpp @@ -25,6 +25,7 @@ #include "Plugins/Process/Windows/Common/ProcessWindowsLog.h" +#include "lldb/Utility/LLDBLog.h" #include "llvm/ADT/STLExtras.h" #include "llvm/Support/ConvertUTF.h" #include "llvm/Support/Threading.h" @@ -40,9 +41,45 @@ using namespace lldb; using namespace lldb_private; +typedef BOOL WINAPI WaitForDebugEventFn(LPDEBUG_EVENT, DWORD); +static WaitForDebugEventFn *g_wait_for_debug_event = nullptr; + +static WaitForDebugEventFn *GetWaitForDebugEventEx() { + HMODULE h_kernel32 = LoadLibraryW(L"kernel32.dll"); + if (!h_kernel32) { + llvm::Error err = llvm::errorCodeToError( + std::error_code(GetLastError(), std::system_category())); + LLDB_LOG_ERROR(GetLog(LLDBLog::Host), std::move(err), + "Could not load kernel32: {0}"); + return nullptr; + } + + return reinterpret_cast<WaitForDebugEventFn *>( + GetProcAddress(h_kernel32, "WaitForDebugEventEx")); +} + +/// WaitForDebugEventEx is only available on Windows 10+. This lazily checks if +/// the function is available and falls back to WaitForDebugEvent if +/// unavailable. The -Ex version ensures correct forwarding of +/// OutputDebugStringW events. +static void InitializeWaitForDebugEvent() { + if (g_wait_for_debug_event) + return; + + g_wait_for_debug_event = GetWaitForDebugEventEx(); + if (!g_wait_for_debug_event) { + LLDB_LOG( + GetLog(LLDBLog::Host), + "WaitForDebugEventEx unavailable, using WaitForDebugEvent instead. " + "Unicode strings from OutputDebugStringW might show incorrectly."); + g_wait_for_debug_event = &WaitForDebugEvent; + } +} + DebuggerThread::DebuggerThread(DebugDelegateSP debug_delegate) : m_debug_delegate(debug_delegate), m_pid_to_detach(0), m_is_shutting_down(false) { + InitializeWaitForDebugEvent(); m_debugging_ended_event = ::CreateEvent(nullptr, TRUE, FALSE, nullptr); } @@ -236,7 +273,7 @@ void DebuggerThread::DebugLoop() { LLDB_LOG_VERBOSE(log, "Entering WaitForDebugEvent loop"); while (should_debug) { LLDB_LOG_VERBOSE(log, "Calling WaitForDebugEvent"); - BOOL wait_result = WaitForDebugEvent(&dbe, INFINITE); + BOOL wait_result = g_wait_for_debug_event(&dbe, INFINITE); if (wait_result) { DWORD continue_status = DBG_CONTINUE; bool shutting_down = m_is_shutting_down; @@ -314,7 +351,7 @@ void DebuggerThread::DebugLoop() { // target threads are running at this time, there is possibility to // have some breakpoint exception between last WaitForDebugEvent and // DebugActiveProcessStop but ignore for now. - while (WaitForDebugEvent(&dbe, 0)) { + while (g_wait_for_debug_event(&dbe, 0)) { continue_status = DBG_CONTINUE; if (dbe.dwDebugEventCode == EXCEPTION_DEBUG_EVENT && !(dbe.u.Exception.ExceptionRecord.ExceptionCode == _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
