https://github.com/charles-zablit updated https://github.com/llvm/llvm-project/pull/175812
>From dc27faa0750f8a9a77dc4a0edd387da61ef15d29 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 13 Jan 2026 18:54:43 +0000 Subject: [PATCH 01/15] [lldb][windows] prevent IOHandlerProcessSTDIOWindows from consuming non text inputs --- .../Process/Windows/Common/ProcessWindows.cpp | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 226cc147aadae..e135628d9009b 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -984,6 +984,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { HANDLE hInterrupt = (HANDLE)_get_osfhandle(m_pipe.GetReadFileDescriptor()); HANDLE waitHandles[2] = {hStdin, hInterrupt}; + DWORD consoleMode; + bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; + while (true) { { std::lock_guard<std::mutex> guard(m_mutex); @@ -996,6 +999,20 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { case WAIT_FAILED: goto exit_loop; case WAIT_OBJECT_0: { + if (isConsole) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + // We only care about text input. Ignore all non text input events and + // let other IOHandlers handle them. + if (inputRecord.EventType != KEY_EVENT || + !inputRecord.Event.KeyEvent.bKeyDown || + inputRecord.Event.KeyEvent.uChar.AsciiChar == 0) + break; + } + char ch = 0; DWORD read = 0; if (!ReadFile(hStdin, &ch, 1, &read, nullptr) || read != 1) >From 319724127263f589eedded0c9acbd9ccbd6c63f8 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 13:50:09 +0000 Subject: [PATCH 02/15] consume non text input --- .../Process/Windows/Common/ProcessWindows.cpp | 28 +++++++++++-------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index e135628d9009b..71dbb3d964804 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1000,17 +1000,23 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { goto exit_loop; case WAIT_OBJECT_0: { if (isConsole) { - INPUT_RECORD inputRecord; - DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) - goto exit_loop; - // We only care about text input. Ignore all non text input events and - // let other IOHandlers handle them. - if (inputRecord.EventType != KEY_EVENT || - !inputRecord.Event.KeyEvent.bKeyDown || - inputRecord.Event.KeyEvent.uChar.AsciiChar == 0) - break; + while (true) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + + // We only care about text input. Consume all non text input events before letting ReadFile handle text input. + if (inputRecord.EventType == KEY_EVENT && + inputRecord.Event.KeyEvent.bKeyDown && + inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) + break; + + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead) || + numRead == 0) + goto exit_loop; + } } char ch = 0; >From 01d9cebd8c3ab18553ecf71c86bb85fbb7bf78dd Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 13:57:50 +0000 Subject: [PATCH 03/15] fix formatting --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 71dbb3d964804..0cdb51cc5a086 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1007,7 +1007,8 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { numRead == 0) goto exit_loop; - // We only care about text input. Consume all non text input events before letting ReadFile handle text input. + // We only care about text input. Consume all non text input events + // before letting ReadFile handle text input. if (inputRecord.EventType == KEY_EVENT && inputRecord.Event.KeyEvent.bKeyDown && inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) >From 071b55b80df6d0976b58cd384db56e39dd6d8171 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 15:50:09 +0000 Subject: [PATCH 04/15] fix control flow --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 0cdb51cc5a086..0d68240c2749d 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1003,8 +1003,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { while (true) { INPUT_RECORD inputRecord; DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; // We only care about text input. Consume all non text input events >From 33cb556acde1c6710cf7a2b421c2aa2ac7110d61 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Mon, 19 Jan 2026 17:32:34 +0000 Subject: [PATCH 05/15] fix control flow --- .../Plugins/Process/Windows/Common/ProcessWindows.cpp | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 0d68240c2749d..a4b46e65617eb 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -988,6 +988,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; while (true) { + read_loop:; { std::lock_guard<std::mutex> guard(m_mutex); if (GetIsDone()) @@ -1006,6 +1007,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; + if (numRead == 0) + goto read_loop; + // We only care about text input. Consume all non text input events // before letting ReadFile handle text input. if (inputRecord.EventType == KEY_EVENT && @@ -1013,8 +1017,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) break; - if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead) || - numRead == 0) + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; } } @@ -1048,7 +1051,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { } exit_loop:; - SetIsRunning(false); + SetIsRunning(false); } void Cancel() override { >From 84959c70fa48e4172e9d1574540e73ecc493de82 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 11:15:27 +0000 Subject: [PATCH 06/15] add comment --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index a4b46e65617eb..940c953089166 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1007,6 +1007,8 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) goto exit_loop; + // If the pipe is empty, go back to waiting on + // WaitForMultipleObjects rather than ReadFile. if (numRead == 0) goto read_loop; @@ -1051,7 +1053,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { } exit_loop:; - SetIsRunning(false); + SetIsRunning(false); } void Cancel() override { >From 91e75a5b6c7ec1d6c639ebaf29ec58504257517a Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 14:33:32 +0000 Subject: [PATCH 07/15] remove secondary pipe --- .../Process/Windows/Common/ProcessWindows.cpp | 109 ++++++++++-------- 1 file changed, 58 insertions(+), 51 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 940c953089166..d16e84b6d307c 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -959,7 +959,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { m_process(process), m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false), m_write_file(conpty_input) { - m_pipe.CreateNew(); + m_interrupt_event = INVALID_HANDLE_VALUE; } ~IOHandlerProcessSTDIOWindows() override = default; @@ -970,9 +970,36 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { m_is_running = running; } + /// Peek the console for input. If it has any, drain the pipe until text input + /// is found or the pipe is empty. + /// + /// \param[in, out] hStdin + /// The handle to the standard input's pipe. + /// + /// \return + /// true if the pipe has text input. + llvm::Expected<bool> ConsoleHasTextInput(HANDLE hStdin) { + while (true) { + INPUT_RECORD inputRecord; + DWORD numRead = 0; + if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) + return llvm::createStringError("Failed to peek standard input."); + + if (numRead == 0) + return false; + + if (inputRecord.EventType == KEY_EVENT && + inputRecord.Event.KeyEvent.bKeyDown && + inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) + return true; + + if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) + return llvm::createStringError("Failed to read standard input."); + } + } + void Run() override { - if (!m_read_file.IsValid() || m_write_file == INVALID_HANDLE_VALUE || - !m_pipe.CanRead() || !m_pipe.CanWrite()) { + if (!m_read_file.IsValid() || m_write_file == INVALID_HANDLE_VALUE) { SetIsDone(true); return; } @@ -980,15 +1007,13 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { SetIsDone(false); SetIsRunning(true); - HANDLE hStdin = (HANDLE)_get_osfhandle(m_read_file.GetDescriptor()); - HANDLE hInterrupt = (HANDLE)_get_osfhandle(m_pipe.GetReadFileDescriptor()); - HANDLE waitHandles[2] = {hStdin, hInterrupt}; + HANDLE hStdin = m_read_file.GetWaitableHandle(); + HANDLE waitHandles[2] = {hStdin, m_interrupt_event}; DWORD consoleMode; bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; while (true) { - read_loop:; { std::lock_guard<std::mutex> guard(m_mutex); if (GetIsDone()) @@ -1001,27 +1026,13 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { goto exit_loop; case WAIT_OBJECT_0: { if (isConsole) { - while (true) { - INPUT_RECORD inputRecord; - DWORD numRead = 0; - if (!PeekConsoleInput(hStdin, &inputRecord, 1, &numRead)) - goto exit_loop; - - // If the pipe is empty, go back to waiting on - // WaitForMultipleObjects rather than ReadFile. - if (numRead == 0) - goto read_loop; - - // We only care about text input. Consume all non text input events - // before letting ReadFile handle text input. - if (inputRecord.EventType == KEY_EVENT && - inputRecord.Event.KeyEvent.bKeyDown && - inputRecord.Event.KeyEvent.uChar.AsciiChar != 0) - break; - - if (!ReadConsoleInput(hStdin, &inputRecord, 1, &numRead)) - goto exit_loop; - } + auto hasInputOrErr = ConsoleHasTextInput(hStdin); + if (hasInputOrErr.takeError()) + goto exit_loop; + + // If no text input is ready, go back to waiting. + if (!*hasInputOrErr) + continue; } char ch = 0; @@ -1035,14 +1046,10 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { break; } case WAIT_OBJECT_0 + 1: { - char ch = 0; - DWORD read = 0; - if (!ReadFile(hInterrupt, &ch, 1, &read, nullptr) || read != 1) + ControlOp op = m_pending_op.exchange(eControlOpNone); + if (op == eControlOpQuit) goto exit_loop; - - if (ch == eControlOpQuit) - goto exit_loop; - if (ch == eControlOpInterrupt && + if (op == eControlOpInterrupt && StateIsRunningState(m_process->GetState())) m_process->SendAsyncInterrupt(); break; @@ -1060,18 +1067,16 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { std::lock_guard<std::mutex> guard(m_mutex); SetIsDone(true); if (m_is_running) { - char ch = eControlOpQuit; - if (llvm::Error err = m_pipe.Write(&ch, 1).takeError()) { - LLDB_LOG_ERROR(GetLog(LLDBLog::Process), std::move(err), - "Pipe write failed: {0}"); - } + m_pending_op.store(eControlOpQuit); + ::SetEvent(m_interrupt_event); } } bool Interrupt() override { if (m_active) { - char ch = eControlOpInterrupt; - return !errorToBool(m_pipe.Write(&ch, 1).takeError()); + m_pending_op.store(eControlOpInterrupt); + ::SetEvent(m_interrupt_event); + return true; } if (StateIsRunningState(m_process->GetState())) { m_process->SendAsyncInterrupt(); @@ -1083,19 +1088,21 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { void GotEOF() override {} private: - Process *m_process; - NativeFile m_read_file; // Read from this file (usually actual STDIN for LLDB - HANDLE m_write_file = - INVALID_HANDLE_VALUE; // Write to this file (usually the primary pty for - // getting io to debuggee) - Pipe m_pipe; - std::mutex m_mutex; - bool m_is_running = false; - enum ControlOp : char { eControlOpQuit = 'q', eControlOpInterrupt = 'i', + eControlOpNone = 0, }; + + Process *m_process; + /// Read from this file (usually actual STDIN for LLDB) + NativeFile m_read_file; + /// Write to this file (usually the primary pty for getting io to debuggee) + HANDLE m_write_file = INVALID_HANDLE_VALUE; + HANDLE m_interrupt_event = INVALID_HANDLE_VALUE; + std::atomic<ControlOp> m_pending_op{eControlOpNone}; + std::mutex m_mutex; + bool m_is_running = false; }; void ProcessWindows::SetPseudoConsoleHandle( >From 9ddd179d5c6193e666071d3c0faa1b800b925533 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Tue, 20 Jan 2026 14:49:09 +0000 Subject: [PATCH 08/15] edit signature --- .../Plugins/Process/Windows/Common/ProcessWindows.cpp | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index d16e84b6d307c..21909fb1b3eba 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -958,9 +958,7 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { IOHandler::Type::ProcessIO), m_process(process), m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false), - m_write_file(conpty_input) { - m_interrupt_event = INVALID_HANDLE_VALUE; - } + m_write_file(conpty_input), m_interrupt_event(INVALID_HANDLE_VALUE) {} ~IOHandlerProcessSTDIOWindows() override = default; @@ -973,12 +971,12 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { /// Peek the console for input. If it has any, drain the pipe until text input /// is found or the pipe is empty. /// - /// \param[in, out] hStdin + /// \param hStdin /// The handle to the standard input's pipe. /// /// \return /// true if the pipe has text input. - llvm::Expected<bool> ConsoleHasTextInput(HANDLE hStdin) { + llvm::Expected<bool> ConsoleHasTextInput(const HANDLE hStdin) { while (true) { INPUT_RECORD inputRecord; DWORD numRead = 0; >From 7fbc30bae0d4a0951b89bf07d93ed715ac35b78e Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Wed, 21 Jan 2026 15:49:16 +0000 Subject: [PATCH 09/15] fix stdin --- .../Host/windows/ProcessLauncherWindows.cpp | 7 ++--- .../Process/Windows/Common/ProcessWindows.cpp | 29 ++++++++++++++++--- 2 files changed, 28 insertions(+), 8 deletions(-) diff --git a/lldb/source/Host/windows/ProcessLauncherWindows.cpp b/lldb/source/Host/windows/ProcessLauncherWindows.cpp index 76feceadf46f3..a8b27e6a30528 100644 --- a/lldb/source/Host/windows/ProcessLauncherWindows.cpp +++ b/lldb/source/Host/windows/ProcessLauncherWindows.cpp @@ -116,9 +116,8 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info, startupinfoex.StartupInfo.dwFlags |= STARTF_USESTDHANDLES; HPCON hPC = launch_info.GetPTY().GetPseudoTerminalHandle(); - bool use_pty = hPC != INVALID_HANDLE_VALUE && - launch_info.GetNumFileActions() == 0 && - launch_info.GetFlags().Test(lldb::eLaunchFlagLaunchInTTY); + bool use_pty = + hPC != INVALID_HANDLE_VALUE && launch_info.GetNumFileActions() == 0; HANDLE stdin_handle = GetStdioHandle(launch_info, STDIN_FILENO); HANDLE stdout_handle = GetStdioHandle(launch_info, STDOUT_FILENO); @@ -199,7 +198,7 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info, BOOL result = ::CreateProcessW( wexecutable.c_str(), pwcommandLine, NULL, NULL, - /*bInheritHandles=*/!inherited_handles.empty(), flags, environment.data(), + /*bInheritHandles=*/TRUE, flags, environment.data(), wworkingDirectory.size() == 0 ? NULL : wworkingDirectory.c_str(), reinterpret_cast<STARTUPINFOW *>(&startupinfoex), &pi); diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 21909fb1b3eba..e72ef1da4b620 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -958,9 +958,15 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { IOHandler::Type::ProcessIO), m_process(process), m_read_file(GetInputFD(), File::eOpenOptionReadOnly, false), - m_write_file(conpty_input), m_interrupt_event(INVALID_HANDLE_VALUE) {} - - ~IOHandlerProcessSTDIOWindows() override = default; + m_write_file(conpty_input), + m_interrupt_event( + CreateEvent(/*lpEventAttributes=*/NULL, /*bManualReset=*/FALSE, + /*bInitialState=*/FALSE, /*lpName=*/NULL)) {} + + ~IOHandlerProcessSTDIOWindows() override { + if (m_interrupt_event != INVALID_HANDLE_VALUE) + ::CloseHandle(m_interrupt_event); + } void SetIsRunning(bool running) { std::lock_guard<std::mutex> guard(m_mutex); @@ -977,6 +983,14 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { /// \return /// true if the pipe has text input. llvm::Expected<bool> ConsoleHasTextInput(const HANDLE hStdin) { + // Check if there are already characters buffered. Pressing enter counts as + // 2 characters '\r\n' and only one of them is a keyDown event. + DWORD bytesAvailable = 0; + if (PeekNamedPipe(hStdin, NULL, 0, NULL, &bytesAvailable, NULL)) { + if (bytesAvailable > 0) + return true; + } + while (true) { INPUT_RECORD inputRecord; DWORD numRead = 0; @@ -1010,6 +1024,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { DWORD consoleMode; bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; + DWORD oldConsoleMode = consoleMode; + SetConsoleMode(hStdin, + consoleMode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT); while (true) { { @@ -1025,8 +1042,10 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { case WAIT_OBJECT_0: { if (isConsole) { auto hasInputOrErr = ConsoleHasTextInput(hStdin); - if (hasInputOrErr.takeError()) + if (!hasInputOrErr) { + llvm::consumeError(hasInputOrErr.takeError()); goto exit_loop; + } // If no text input is ready, go back to waiting. if (!*hasInputOrErr) @@ -1059,6 +1078,8 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { exit_loop:; SetIsRunning(false); + SetIsDone(true); + SetConsoleMode(hStdin, oldConsoleMode); } void Cancel() override { >From ad5d8e4214d6d584ee87e7f9382e53eab4190ea0 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Thu, 22 Jan 2026 16:33:01 +0000 Subject: [PATCH 10/15] drain conpty escape sequences --- .../include/lldb/Host/windows/PseudoConsole.h | 10 ++++ lldb/source/Host/windows/PseudoConsole.cpp | 50 +++++++++++++++++++ 2 files changed, 60 insertions(+) diff --git a/lldb/include/lldb/Host/windows/PseudoConsole.h b/lldb/include/lldb/Host/windows/PseudoConsole.h index 039783985c025..7a9829e23a097 100644 --- a/lldb/include/lldb/Host/windows/PseudoConsole.h +++ b/lldb/include/lldb/Host/windows/PseudoConsole.h @@ -61,6 +61,16 @@ class PseudoConsole { /// invalid. HANDLE GetSTDINHandle() const { return m_conpty_input; }; + /// Drains initialization sequences from the ConPTY output pipe. + /// + /// When a process first attaches to a ConPTY, Windows emits VT100/ANSI escape + /// sequences (ESC[2J for clear screen, ESC[H for cursor home and more) as + /// part of the PseudoConsole initialization. To prevent these sequences from + /// appearing in the debugger output (and flushing lldb's shell for instance) + /// we launch a short-lived dummy process that triggers the initialization, + /// then drain all output before launching the actual debuggee. + llvm::Error DrainInitSequences(); + protected: HANDLE m_conpty_handle = ((HANDLE)(long long)-1); HANDLE m_conpty_output = ((HANDLE)(long long)-1); diff --git a/lldb/source/Host/windows/PseudoConsole.cpp b/lldb/source/Host/windows/PseudoConsole.cpp index b3314fd58bbb8..b10e702a915a2 100644 --- a/lldb/source/Host/windows/PseudoConsole.cpp +++ b/lldb/source/Host/windows/PseudoConsole.cpp @@ -11,6 +11,7 @@ #include <mutex> #include "lldb/Host/windows/PipeWindows.h" +#include "lldb/Host/windows/ProcessLauncherWindows.h" #include "lldb/Host/windows/windows.h" #include "lldb/Utility/LLDBLog.h" @@ -118,6 +119,9 @@ llvm::Error PseudoConsole::OpenPseudoConsole() { m_conpty_output = hOutputRead; m_conpty_input = hInputWrite; + if (auto err = DrainInitSequences()) + return err; + return llvm::Error::success(); } @@ -133,3 +137,49 @@ void PseudoConsole::Close() { m_conpty_input = INVALID_HANDLE_VALUE; m_conpty_output = INVALID_HANDLE_VALUE; } + +llvm::Error PseudoConsole::DrainInitSequences() { + STARTUPINFOEXW startupinfoex = {}; + startupinfoex.StartupInfo.cb = sizeof(STARTUPINFOEXW); + startupinfoex.StartupInfo.dwFlags |= STARTF_USESTDHANDLES; + + auto attributelist_or_err = ProcThreadAttributeList::Create(startupinfoex); + if (!attributelist_or_err) + return llvm::errorCodeToError(attributelist_or_err.getError()); + + PROCESS_INFORMATION pi = {}; + wchar_t cmdline[] = L"echo foo"; + + if (!CreateProcessW(/*lpApplicationName=*/NULL, cmdline, + /*lpProcessAttributes=*/NULL, /*lpThreadAttributes=*/NULL, + /*bInheritHandles=*/TRUE, + /*dwCreationFlags=*/EXTENDED_STARTUPINFO_PRESENT | + CREATE_UNICODE_ENVIRONMENT, + /*lpEnvironment=*/NULL, /*lpCurrentDirectory=*/NULL, + /*lpStartupInfo=*/ + reinterpret_cast<STARTUPINFOW *>(&startupinfoex), + /*lpProcessInformation=*/&pi)) + return llvm::errorCodeToError( + std::error_code(GetLastError(), std::system_category())); + + char buf[4096]; + OVERLAPPED ov = {}; + ov.hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); + + DWORD read; + ReadFile(m_conpty_output, buf, sizeof(buf), &read, &ov); + + WaitForSingleObject(pi.hProcess, INFINITE); + + if (GetOverlappedResult(m_conpty_output, &ov, &read, FALSE) && read > 0) { + ResetEvent(ov.hEvent); + ReadFile(m_conpty_output, buf, sizeof(buf), &read, &ov); + } + + CancelIo(m_conpty_output); + CloseHandle(ov.hEvent); + CloseHandle(pi.hProcess); + CloseHandle(pi.hThread); + + return llvm::Error::success(); +} \ No newline at end of file >From 37b6bc3603ade31d299522623f6568293c63bf84 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Thu, 22 Jan 2026 16:33:22 +0000 Subject: [PATCH 11/15] fix tests --- lldb/test/Shell/Settings/TestFrameFormatColor.test | 2 +- lldb/test/Shell/Settings/TestFrameFormatNoColor.test | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/lldb/test/Shell/Settings/TestFrameFormatColor.test b/lldb/test/Shell/Settings/TestFrameFormatColor.test index 970d7238e7512..f30dafadf5919 100644 --- a/lldb/test/Shell/Settings/TestFrameFormatColor.test +++ b/lldb/test/Shell/Settings/TestFrameFormatColor.test @@ -9,4 +9,4 @@ c q # Check the ASCII escape code -# CHECK: +# CHECK: {{\[[0-9;]+m}} diff --git a/lldb/test/Shell/Settings/TestFrameFormatNoColor.test b/lldb/test/Shell/Settings/TestFrameFormatNoColor.test index 2bcdb8e82bd9d..37906311c4f69 100644 --- a/lldb/test/Shell/Settings/TestFrameFormatNoColor.test +++ b/lldb/test/Shell/Settings/TestFrameFormatNoColor.test @@ -9,4 +9,4 @@ c q # Check the ASCII escape code -# CHECK-NOT: +# CHECK-NOT: {{\[[0-9;]+m}} >From 01a9e36dd61a6cbbe275268eab587b39e5fbba19 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Thu, 22 Jan 2026 16:37:44 +0000 Subject: [PATCH 12/15] add comment --- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index e72ef1da4b620..7a9aea38876b6 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1024,6 +1024,10 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { DWORD consoleMode; bool isConsole = GetConsoleMode(hStdin, &consoleMode) != 0; + // With ENABLE_LINE_INPUT, ReadFile returns only when a carriage return is + // read. This will block lldb in ReadFile until the user hits enter. Save + // the previous console mode to restore it later and remove + // ENABLE_LINE_INPUT. DWORD oldConsoleMode = consoleMode; SetConsoleMode(hStdin, consoleMode & ~ENABLE_LINE_INPUT & ~ENABLE_ECHO_INPUT); >From ad5794a0e6257f83dd63981db214bd52c04bf584 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Thu, 22 Jan 2026 17:54:35 +0000 Subject: [PATCH 13/15] setup pseudoconsole --- .../lldb/Host/windows/ProcessLauncherWindows.h | 9 ++++++++- .../Host/windows/ProcessLauncherWindows.cpp | 17 +++++++++++++---- lldb/source/Host/windows/PseudoConsole.cpp | 5 ++++- 3 files changed, 25 insertions(+), 6 deletions(-) diff --git a/lldb/include/lldb/Host/windows/ProcessLauncherWindows.h b/lldb/include/lldb/Host/windows/ProcessLauncherWindows.h index b835885dd47c6..7f99a46447966 100644 --- a/lldb/include/lldb/Host/windows/ProcessLauncherWindows.h +++ b/lldb/include/lldb/Host/windows/ProcessLauncherWindows.h @@ -11,7 +11,7 @@ #include "lldb/Host/ProcessLauncher.h" #include "lldb/Host/windows/windows.h" -#include "llvm/Support/ErrorOr.h" +#include "llvm/Support/Error.h" namespace lldb_private { @@ -38,6 +38,13 @@ class ProcThreadAttributeList { static llvm::ErrorOr<ProcThreadAttributeList> Create(STARTUPINFOEXW &startupinfoex); + /// Setup the PseudoConsole handle in the underlying + /// LPPROC_THREAD_ATTRIBUTE_LIST. + /// + /// \param hPC + /// The handle to the PseudoConsole. + llvm::Error SetupPseudoConsole(HPCON hPC); + ~ProcThreadAttributeList() { if (lpAttributeList) { DeleteProcThreadAttributeList(lpAttributeList); diff --git a/lldb/source/Host/windows/ProcessLauncherWindows.cpp b/lldb/source/Host/windows/ProcessLauncherWindows.cpp index a8b27e6a30528..907f0fc86bd89 100644 --- a/lldb/source/Host/windows/ProcessLauncherWindows.cpp +++ b/lldb/source/Host/windows/ProcessLauncherWindows.cpp @@ -106,6 +106,15 @@ ProcThreadAttributeList::Create(STARTUPINFOEXW &startupinfoex) { return ProcThreadAttributeList(startupinfoex.lpAttributeList); } +llvm::Error ProcThreadAttributeList::SetupPseudoConsole(HPCON hPC) { + BOOL ok = UpdateProcThreadAttribute(lpAttributeList, 0, + PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE, hPC, + sizeof(hPC), NULL, NULL); + if (!ok) + return llvm::errorCodeToError(llvm::mapWindowsError(GetLastError())); + return llvm::Error::success(); +} + HostProcess ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info, Status &error) { @@ -136,15 +145,15 @@ ProcessLauncherWindows::LaunchProcess(const ProcessLaunchInfo &launch_info, error = attributelist_or_err.getError(); return HostProcess(); } + ProcThreadAttributeList attributelist = std::move(*attributelist_or_err); + llvm::scope_exit delete_attributelist( [&] { DeleteProcThreadAttributeList(startupinfoex.lpAttributeList); }); std::vector<HANDLE> inherited_handles; if (use_pty) { - if (!UpdateProcThreadAttribute(startupinfoex.lpAttributeList, 0, - PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE, hPC, - sizeof(hPC), NULL, NULL)) { - error = Status(::GetLastError(), eErrorTypeWin32); + if (auto err = attributelist.SetupPseudoConsole(hPC)) { + error = Status::FromError(std::move(err)); return HostProcess(); } } else { diff --git a/lldb/source/Host/windows/PseudoConsole.cpp b/lldb/source/Host/windows/PseudoConsole.cpp index b10e702a915a2..516015f7eab10 100644 --- a/lldb/source/Host/windows/PseudoConsole.cpp +++ b/lldb/source/Host/windows/PseudoConsole.cpp @@ -146,9 +146,12 @@ llvm::Error PseudoConsole::DrainInitSequences() { auto attributelist_or_err = ProcThreadAttributeList::Create(startupinfoex); if (!attributelist_or_err) return llvm::errorCodeToError(attributelist_or_err.getError()); + ProcThreadAttributeList attributelist = std::move(*attributelist_or_err); + if (auto error = attributelist.SetupPseudoConsole(m_conpty_handle)) + return error; PROCESS_INFORMATION pi = {}; - wchar_t cmdline[] = L"echo foo"; + wchar_t cmdline[] = L"cmd.exe /c 'echo foo && exit'"; if (!CreateProcessW(/*lpApplicationName=*/NULL, cmdline, /*lpProcessAttributes=*/NULL, /*lpThreadAttributes=*/NULL, >From fcb68b5222471a4518b7fac946fdaab0180d1e00 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Thu, 22 Jan 2026 19:43:10 +0000 Subject: [PATCH 14/15] use COMSPEC --- lldb/source/Host/windows/PseudoConsole.cpp | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/lldb/source/Host/windows/PseudoConsole.cpp b/lldb/source/Host/windows/PseudoConsole.cpp index 516015f7eab10..793e39114e53b 100644 --- a/lldb/source/Host/windows/PseudoConsole.cpp +++ b/lldb/source/Host/windows/PseudoConsole.cpp @@ -119,8 +119,10 @@ llvm::Error PseudoConsole::OpenPseudoConsole() { m_conpty_output = hOutputRead; m_conpty_input = hInputWrite; - if (auto err = DrainInitSequences()) - return err; + if (auto error = DrainInitSequences()) { + Log *log = GetLog(LLDBLog::Host); + LLDB_LOG(log, "error: {0}", error); + } return llvm::Error::success(); } @@ -151,9 +153,19 @@ llvm::Error PseudoConsole::DrainInitSequences() { return error; PROCESS_INFORMATION pi = {}; - wchar_t cmdline[] = L"cmd.exe /c 'echo foo && exit'"; - if (!CreateProcessW(/*lpApplicationName=*/NULL, cmdline, + wchar_t comspec[MAX_PATH]; + DWORD comspecLen = GetEnvironmentVariableW(L"COMSPEC", comspec, MAX_PATH); + if (comspecLen == 0 || comspecLen >= MAX_PATH) + return llvm::createStringError( + std::error_code(GetLastError(), std::system_category()), + "Failed to get the 'COMSPEC' environment variable"); + + std::wstring cmdline_str = std::wstring(comspec) + L" /c 'echo foo && exit'"; + std::vector<wchar_t> cmdline(cmdline_str.begin(), cmdline_str.end()); + cmdline.push_back(L'\0'); + + if (!CreateProcessW(/*lpApplicationName=*/comspec, cmdline.data(), /*lpProcessAttributes=*/NULL, /*lpThreadAttributes=*/NULL, /*bInheritHandles=*/TRUE, /*dwCreationFlags=*/EXTENDED_STARTUPINFO_PRESENT | @@ -185,4 +197,4 @@ llvm::Error PseudoConsole::DrainInitSequences() { CloseHandle(pi.hThread); return llvm::Error::success(); -} \ No newline at end of file +} >From db68e85c82ecfe525d3764f2a9746bba66339f08 Mon Sep 17 00:00:00 2001 From: Charles Zablit <[email protected]> Date: Fri, 23 Jan 2026 12:27:01 +0000 Subject: [PATCH 15/15] switch to using LLDB_LOG_ERROR --- lldb/source/Host/windows/PseudoConsole.cpp | 3 ++- lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp | 4 +++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/lldb/source/Host/windows/PseudoConsole.cpp b/lldb/source/Host/windows/PseudoConsole.cpp index 793e39114e53b..413c8a3328445 100644 --- a/lldb/source/Host/windows/PseudoConsole.cpp +++ b/lldb/source/Host/windows/PseudoConsole.cpp @@ -121,7 +121,8 @@ llvm::Error PseudoConsole::OpenPseudoConsole() { if (auto error = DrainInitSequences()) { Log *log = GetLog(LLDBLog::Host); - LLDB_LOG(log, "error: {0}", error); + LLDB_LOG_ERROR(log, std::move(error), + "failed to finalize ConPTY's setup: {0}"); } return llvm::Error::success(); diff --git a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp index 7a9aea38876b6..373729c952071 100644 --- a/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp +++ b/lldb/source/Plugins/Process/Windows/Common/ProcessWindows.cpp @@ -1047,7 +1047,9 @@ class IOHandlerProcessSTDIOWindows : public IOHandler { if (isConsole) { auto hasInputOrErr = ConsoleHasTextInput(hStdin); if (!hasInputOrErr) { - llvm::consumeError(hasInputOrErr.takeError()); + Log *log = GetLog(WindowsLog::Process); + LLDB_LOG_ERROR(log, hasInputOrErr.takeError(), + "failed to process debuggee's IO: {0}"); goto exit_loop; } _______________________________________________ lldb-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
