llvm/lib/Support/Windows/Program.inc - toolchain/llvm-project - Gitiles

 //===- Win32/Program.cpp - Win32 Program Implementation ------- -*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file provides the Win32 specific implementation of the Program class.
 //
 //===----------------------------------------------------------------------===//

 #include "WindowsSupport.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/Errc.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/WindowsError.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstdio>
 #include <fcntl.h>
 #include <io.h>
 #include <malloc.h>
 #include <numeric>

 //===----------------------------------------------------------------------===//
 //=== WARNING: Implementation here must contain only Win32 specific code
 //===          and must not be UNIX code
 //===----------------------------------------------------------------------===//

 namespace llvm {

 ProcessInfo::ProcessInfo() : Pid(0), Process(0), ReturnCode(0) {}

 ErrorOr<std::string> sys::findProgramByName(StringRef Name,
                                             ArrayRef<StringRef> Paths) {
   assert(!Name.empty() && "Must have a name!");

   if (Name.find_first_of("/\\") != StringRef::npos)
     return std::string(Name);

   const wchar_t *Path = nullptr;
   std::wstring PathStorage;
   if (!Paths.empty()) {
     PathStorage.reserve(Paths.size() * MAX_PATH);
     for (unsigned i = 0; i < Paths.size(); ++i) {
       if (i)
         PathStorage.push_back(L';');
       StringRef P = Paths[i];
       SmallVector<wchar_t, MAX_PATH> TmpPath;
       if (std::error_code EC = windows::UTF8ToUTF16(P, TmpPath))
         return EC;
       PathStorage.append(TmpPath.begin(), TmpPath.end());
     }
     Path = PathStorage.c_str();
   }

   SmallVector<wchar_t, MAX_PATH> U16Name;
   if (std::error_code EC = windows::UTF8ToUTF16(Name, U16Name))
     return EC;

   SmallVector<StringRef, 12> PathExts;
   PathExts.push_back("");
   PathExts.push_back(".exe"); // FIXME: This must be in %PATHEXT%.
   if (const char *PathExtEnv = std::getenv("PATHEXT"))
     SplitString(PathExtEnv, PathExts, ";");

   SmallVector<wchar_t, MAX_PATH> U16Result;
   DWORD Len = MAX_PATH;
   for (StringRef Ext : PathExts) {
     SmallVector<wchar_t, MAX_PATH> U16Ext;
     if (std::error_code EC = windows::UTF8ToUTF16(Ext, U16Ext))
       return EC;

     do {
       U16Result.reserve(Len);
       // Lets attach the extension manually. That is needed for files
       // with a point in name like aaa.bbb. SearchPathW will not add extension
       // from its argument to such files because it thinks they already had one.
       SmallVector<wchar_t, MAX_PATH> U16NameExt;
       if (std::error_code EC =
               windows::UTF8ToUTF16(Twine(Name + Ext).str(), U16NameExt))
         return EC;

       Len = ::SearchPathW(Path, c_str(U16NameExt), nullptr,
                           U16Result.capacity(), U16Result.data(), nullptr);
     } while (Len > U16Result.capacity());

     if (Len != 0)
       break; // Found it.
   }

   if (Len == 0)
     return mapWindowsError(::GetLastError());

   U16Result.set_size(Len);

   SmallVector<char, MAX_PATH> U8Result;
   if (std::error_code EC =
           windows::UTF16ToUTF8(U16Result.data(), U16Result.size(), U8Result))
     return EC;

   return std::string(U8Result.begin(), U8Result.end());
 }

 bool MakeErrMsg(std::string *ErrMsg, const std::string &prefix) {
   if (!ErrMsg)
     return true;
   char *buffer = NULL;
   DWORD LastError = GetLastError();
   DWORD R = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
                                FORMAT_MESSAGE_FROM_SYSTEM |
                                FORMAT_MESSAGE_MAX_WIDTH_MASK,
                            NULL, LastError, 0, (LPSTR)&buffer, 1, NULL);
   if (R)
     *ErrMsg = prefix + ": " + buffer;
   else
     *ErrMsg = prefix + ": Unknown error";
   *ErrMsg += " (0x" + llvm::utohexstr(LastError) + ")";

   LocalFree(buffer);
   return R != 0;
 }

 static HANDLE RedirectIO(Optional<StringRef> Path, int fd,
                          std::string *ErrMsg) {
   HANDLE h;
   if (!Path) {
     if (!DuplicateHandle(GetCurrentProcess(), (HANDLE)_get_osfhandle(fd),
                          GetCurrentProcess(), &h,
                          0, TRUE, DUPLICATE_SAME_ACCESS))
       return INVALID_HANDLE_VALUE;
     return h;
   }

   std::string fname;
   if (Path->empty())
     fname = "NUL";
   else
     fname = *Path;

   SECURITY_ATTRIBUTES sa;
   sa.nLength = sizeof(sa);
   sa.lpSecurityDescriptor = 0;
   sa.bInheritHandle = TRUE;

   SmallVector<wchar_t, 128> fnameUnicode;
   if (Path->empty()) {
     // Don't play long-path tricks on "NUL".
     if (windows::UTF8ToUTF16(fname, fnameUnicode))
       return INVALID_HANDLE_VALUE;
   } else {
     if (path::widenPath(fname, fnameUnicode))
       return INVALID_HANDLE_VALUE;
   }
   h = CreateFileW(fnameUnicode.data(), fd ? GENERIC_WRITE : GENERIC_READ,
                   FILE_SHARE_READ, &sa, fd == 0 ? OPEN_EXISTING : CREATE_ALWAYS,
                   FILE_ATTRIBUTE_NORMAL, NULL);
   if (h == INVALID_HANDLE_VALUE) {
     MakeErrMsg(ErrMsg, fname + ": Can't open file for " +
         (fd ? "input" : "output"));
   }

   return h;
 }

 }

 static bool Execute(ProcessInfo &PI, StringRef Program,
                     ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
                     ArrayRef<Optional<StringRef>> Redirects,
                     unsigned MemoryLimit, std::string *ErrMsg) {
   if (!sys::fs::can_execute(Program)) {
     if (ErrMsg)
       *ErrMsg = "program not executable";
     return false;
   }

   // can_execute may succeed by looking at Program + ".exe". CreateProcessW
   // will implicitly add the .exe if we provide a command line without an
   // executable path, but since we use an explicit executable, we have to add
   // ".exe" ourselves.
   SmallString<64> ProgramStorage;
   if (!sys::fs::exists(Program))
     Program = Twine(Program + ".exe").toStringRef(ProgramStorage);

   // Windows wants a command line, not an array of args, to pass to the new
   // process.  We have to concatenate them all, while quoting the args that
   // have embedded spaces (or are empty).
   std::string Command = flattenWindowsCommandLine(Args);

   // The pointer to the environment block for the new process.
   std::vector<wchar_t> EnvBlock;

   if (Env) {
     // An environment block consists of a null-terminated block of
     // null-terminated strings. Convert the array of environment variables to
     // an environment block by concatenating them.
     for (const auto E : *Env) {
       SmallVector<wchar_t, MAX_PATH> EnvString;
       if (std::error_code ec = windows::UTF8ToUTF16(E, EnvString)) {
         SetLastError(ec.value());
         MakeErrMsg(ErrMsg, "Unable to convert environment variable to UTF-16");
         return false;
       }

       EnvBlock.insert(EnvBlock.end(), EnvString.begin(), EnvString.end());
       EnvBlock.push_back(0);
     }
     EnvBlock.push_back(0);
   }

   // Create a child process.
   STARTUPINFOW si;
   memset(&si, 0, sizeof(si));
   si.cb = sizeof(si);
   si.hStdInput = INVALID_HANDLE_VALUE;
   si.hStdOutput = INVALID_HANDLE_VALUE;
   si.hStdError = INVALID_HANDLE_VALUE;

   if (!Redirects.empty()) {
     si.dwFlags = STARTF_USESTDHANDLES;

     si.hStdInput = RedirectIO(Redirects[0], 0, ErrMsg);
     if (si.hStdInput == INVALID_HANDLE_VALUE) {
       MakeErrMsg(ErrMsg, "can't redirect stdin");
       return false;
     }
     si.hStdOutput = RedirectIO(Redirects[1], 1, ErrMsg);
     if (si.hStdOutput == INVALID_HANDLE_VALUE) {
       CloseHandle(si.hStdInput);
       MakeErrMsg(ErrMsg, "can't redirect stdout");
       return false;
     }
     if (Redirects[1] && Redirects[2] && *Redirects[1] == *Redirects[2]) {
       // If stdout and stderr should go to the same place, redirect stderr
       // to the handle already open for stdout.
       if (!DuplicateHandle(GetCurrentProcess(), si.hStdOutput,
                            GetCurrentProcess(), &si.hStdError,
                            0, TRUE, DUPLICATE_SAME_ACCESS)) {
         CloseHandle(si.hStdInput);
         CloseHandle(si.hStdOutput);
         MakeErrMsg(ErrMsg, "can't dup stderr to stdout");
         return false;
       }
     } else {
       // Just redirect stderr
       si.hStdError = RedirectIO(Redirects[2], 2, ErrMsg);
       if (si.hStdError == INVALID_HANDLE_VALUE) {
         CloseHandle(si.hStdInput);
         CloseHandle(si.hStdOutput);
         MakeErrMsg(ErrMsg, "can't redirect stderr");
         return false;
       }
     }
   }

   PROCESS_INFORMATION pi;
   memset(&pi, 0, sizeof(pi));

   fflush(stdout);
   fflush(stderr);

   SmallVector<wchar_t, MAX_PATH> ProgramUtf16;
   if (std::error_code ec = path::widenPath(Program, ProgramUtf16)) {
     SetLastError(ec.value());
     MakeErrMsg(ErrMsg,
                std::string("Unable to convert application name to UTF-16"));
     return false;
   }

   SmallVector<wchar_t, MAX_PATH> CommandUtf16;
   if (std::error_code ec = windows::UTF8ToUTF16(Command, CommandUtf16)) {
     SetLastError(ec.value());
     MakeErrMsg(ErrMsg,
                std::string("Unable to convert command-line to UTF-16"));
     return false;
   }

   BOOL rc = CreateProcessW(ProgramUtf16.data(), CommandUtf16.data(), 0, 0,
                            TRUE, CREATE_UNICODE_ENVIRONMENT,
                            EnvBlock.empty() ? 0 : EnvBlock.data(), 0, &si,
                            &pi);
   DWORD err = GetLastError();

   // Regardless of whether the process got created or not, we are done with
   // the handles we created for it to inherit.
   CloseHandle(si.hStdInput);
   CloseHandle(si.hStdOutput);
   CloseHandle(si.hStdError);

   // Now return an error if the process didn't get created.
   if (!rc) {
     SetLastError(err);
     MakeErrMsg(ErrMsg, std::string("Couldn't execute program '") +
                Program.str() + "'");
     return false;
   }

   PI.Pid = pi.dwProcessId;
   PI.Process = pi.hProcess;

   // Make sure these get closed no matter what.
   ScopedCommonHandle hThread(pi.hThread);

   // Assign the process to a job if a memory limit is defined.
   ScopedJobHandle hJob;
   if (MemoryLimit != 0) {
     hJob = CreateJobObjectW(0, 0);
     bool success = false;
     if (hJob) {
       JOBOBJECT_EXTENDED_LIMIT_INFORMATION jeli;
       memset(&jeli, 0, sizeof(jeli));
       jeli.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_PROCESS_MEMORY;
       jeli.ProcessMemoryLimit = uintptr_t(MemoryLimit) * 1048576;
       if (SetInformationJobObject(hJob, JobObjectExtendedLimitInformation,
                                   &jeli, sizeof(jeli))) {
         if (AssignProcessToJobObject(hJob, pi.hProcess))
           success = true;
       }
     }
     if (!success) {
       SetLastError(GetLastError());
       MakeErrMsg(ErrMsg, std::string("Unable to set memory limit"));
       TerminateProcess(pi.hProcess, 1);
       WaitForSingleObject(pi.hProcess, INFINITE);
       return false;
     }
   }

   return true;
 }

 static bool argNeedsQuotes(StringRef Arg) {
   if (Arg.empty())
     return true;
   return StringRef::npos != Arg.find_first_of("\t \"&\'()*<>\\`^|\n");
 }

 static std::string quoteSingleArg(StringRef Arg) {
   std::string Result;
   Result.push_back('"');

   while (!Arg.empty()) {
     size_t FirstNonBackslash = Arg.find_first_not_of('\\');
     size_t BackslashCount = FirstNonBackslash;
     if (FirstNonBackslash == StringRef::npos) {
       // The entire remainder of the argument is backslashes.  Escape all of
       // them and just early out.
       BackslashCount = Arg.size();
       Result.append(BackslashCount * 2, '\\');
       break;
     }

     if (Arg[FirstNonBackslash] == '\"') {
       // This is an embedded quote.  Escape all preceding backslashes, then
       // add one additional backslash to escape the quote.
       Result.append(BackslashCount * 2 + 1, '\\');
       Result.push_back('\"');
     } else {
       // This is just a normal character.  Don't escape any of the preceding
       // backslashes, just append them as they are and then append the
       // character.
       Result.append(BackslashCount, '\\');
       Result.push_back(Arg[FirstNonBackslash]);
     }

     // Drop all the backslashes, plus the following character.
     Arg = Arg.drop_front(FirstNonBackslash + 1);
   }

   Result.push_back('"');
   return Result;
 }

 namespace llvm {
 std::string sys::flattenWindowsCommandLine(ArrayRef<StringRef> Args) {
   std::string Command;
   for (StringRef Arg : Args) {
     if (argNeedsQuotes(Arg))
       Command += quoteSingleArg(Arg);
     else
       Command += Arg;

     Command.push_back(' ');
   }

   return Command;
 }

 ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
                       bool WaitUntilChildTerminates, std::string *ErrMsg) {
   assert(PI.Pid && "invalid pid to wait on, process not started?");
   assert((PI.Process && PI.Process != INVALID_HANDLE_VALUE) &&
          "invalid process handle to wait on, process not started?");
   DWORD milliSecondsToWait = 0;
   if (WaitUntilChildTerminates)
     milliSecondsToWait = INFINITE;
   else if (SecondsToWait > 0)
     milliSecondsToWait = SecondsToWait * 1000;

   ProcessInfo WaitResult = PI;
   DWORD WaitStatus = WaitForSingleObject(PI.Process, milliSecondsToWait);
   if (WaitStatus == WAIT_TIMEOUT) {
     if (SecondsToWait) {
       if (!TerminateProcess(PI.Process, 1)) {
         if (ErrMsg)
           MakeErrMsg(ErrMsg, "Failed to terminate timed-out program");

         // -2 indicates a crash or timeout as opposed to failure to execute.
         WaitResult.ReturnCode = -2;
         CloseHandle(PI.Process);
         return WaitResult;
       }
       WaitForSingleObject(PI.Process, INFINITE);
       CloseHandle(PI.Process);
     } else {
       // Non-blocking wait.
       return ProcessInfo();
     }
   }

   // Get its exit status.
   DWORD status;
   BOOL rc = GetExitCodeProcess(PI.Process, &status);
   DWORD err = GetLastError();
   if (err != ERROR_INVALID_HANDLE)
     CloseHandle(PI.Process);

   if (!rc) {
     SetLastError(err);
     if (ErrMsg)
       MakeErrMsg(ErrMsg, "Failed getting status for program");

     // -2 indicates a crash or timeout as opposed to failure to execute.
     WaitResult.ReturnCode = -2;
     return WaitResult;
   }

   if (!status)
     return WaitResult;

   // Pass 10(Warning) and 11(Error) to the callee as negative value.
   if ((status & 0xBFFF0000U) == 0x80000000U)
     WaitResult.ReturnCode = static_cast<int>(status);
   else if (status & 0xFF)
     WaitResult.ReturnCode = status & 0x7FFFFFFF;
   else
     WaitResult.ReturnCode = 1;

   return WaitResult;
 }

 std::error_code sys::ChangeStdinToBinary() {
   int result = _setmode(_fileno(stdin), _O_BINARY);
   if (result == -1)
     return std::error_code(errno, std::generic_category());
   return std::error_code();
 }

 std::error_code sys::ChangeStdoutToBinary() {
   int result = _setmode(_fileno(stdout), _O_BINARY);
   if (result == -1)
     return std::error_code(errno, std::generic_category());
   return std::error_code();
 }

 std::error_code
 llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
                                  WindowsEncodingMethod Encoding) {
   std::error_code EC;
   llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::F_Text);
   if (EC)
     return EC;

   if (Encoding == WEM_UTF8) {
     OS << Contents;
   } else if (Encoding == WEM_CurrentCodePage) {
     SmallVector<wchar_t, 1> ArgsUTF16;
     SmallVector<char, 1> ArgsCurCP;

     if ((EC = windows::UTF8ToUTF16(Contents, ArgsUTF16)))
       return EC;

     if ((EC = windows::UTF16ToCurCP(
              ArgsUTF16.data(), ArgsUTF16.size(), ArgsCurCP)))
       return EC;

     OS.write(ArgsCurCP.data(), ArgsCurCP.size());
   } else if (Encoding == WEM_UTF16) {
     SmallVector<wchar_t, 1> ArgsUTF16;

     if ((EC = windows::UTF8ToUTF16(Contents, ArgsUTF16)))
       return EC;

     // Endianness guessing
     char BOM[2];
     uint16_t src = UNI_UTF16_BYTE_ORDER_MARK_NATIVE;
     memcpy(BOM, &src, 2);
     OS.write(BOM, 2);
     OS.write((char *)ArgsUTF16.data(), ArgsUTF16.size() << 1);
   } else {
     llvm_unreachable("Unknown encoding");
   }

   if (OS.has_error())
     return make_error_code(errc::io_error);

   return EC;
 }

 bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
                                                   ArrayRef<StringRef> Args) {
   // The documented max length of the command line passed to CreateProcess.
   static const size_t MaxCommandStringLength = 32768;
   SmallVector<StringRef, 8> FullArgs;
   FullArgs.push_back(Program);
   FullArgs.append(Args.begin(), Args.end());
   std::string Result = flattenWindowsCommandLine(FullArgs);
   return (Result.size() + 1) <= MaxCommandStringLength;
 }
 }
	//===- Win32/Program.cpp - Win32 Program Implementation ------- -- C++ --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//
	//
	// This file provides the Win32 specific implementation of the Program class.
	//
	//===----------------------------------------------------------------------===//

	#include "WindowsSupport.h"
	#include "llvm/ADT/StringExtras.h"
	#include "llvm/Support/ConvertUTF.h"
	#include "llvm/Support/Errc.h"
	#include "llvm/Support/FileSystem.h"
	#include "llvm/Support/Path.h"
	#include "llvm/Support/WindowsError.h"
	#include "llvm/Support/raw_ostream.h"
	#include <cstdio>
	#include <fcntl.h>
	#include <io.h>
	#include <malloc.h>
	#include <numeric>

	//===----------------------------------------------------------------------===//
	//=== WARNING: Implementation here must contain only Win32 specific code
	//=== and must not be UNIX code
	//===----------------------------------------------------------------------===//

	namespace llvm {

	ProcessInfo::ProcessInfo() : Pid(0), Process(0), ReturnCode(0) {}

	ErrorOr<std::string> sys::findProgramByName(StringRef Name,
	ArrayRef<StringRef> Paths) {
	assert(!Name.empty() && "Must have a name!");

	if (Name.find_first_of("/\\") != StringRef::npos)
	return std::string(Name);

	const wchar_t *Path = nullptr;
	std::wstring PathStorage;
	if (!Paths.empty()) {
	PathStorage.reserve(Paths.size() * MAX_PATH);
	for (unsigned i = 0; i < Paths.size(); ++i) {
	if (i)
	PathStorage.push_back(L';');
	StringRef P = Paths[i];
	SmallVector<wchar_t, MAX_PATH> TmpPath;
	if (std::error_code EC = windows::UTF8ToUTF16(P, TmpPath))
	return EC;
	PathStorage.append(TmpPath.begin(), TmpPath.end());
	}
	Path = PathStorage.c_str();
	}

	SmallVector<wchar_t, MAX_PATH> U16Name;
	if (std::error_code EC = windows::UTF8ToUTF16(Name, U16Name))
	return EC;

	SmallVector<StringRef, 12> PathExts;
	PathExts.push_back("");
	PathExts.push_back(".exe"); // FIXME: This must be in %PATHEXT%.
	if (const char *PathExtEnv = std::getenv("PATHEXT"))
	SplitString(PathExtEnv, PathExts, ";");

	SmallVector<wchar_t, MAX_PATH> U16Result;
	DWORD Len = MAX_PATH;
	for (StringRef Ext : PathExts) {
	SmallVector<wchar_t, MAX_PATH> U16Ext;
	if (std::error_code EC = windows::UTF8ToUTF16(Ext, U16Ext))
	return EC;

	do {
	U16Result.reserve(Len);
	// Lets attach the extension manually. That is needed for files
	// with a point in name like aaa.bbb. SearchPathW will not add extension
	// from its argument to such files because it thinks they already had one.
	SmallVector<wchar_t, MAX_PATH> U16NameExt;
	if (std::error_code EC =
	windows::UTF8ToUTF16(Twine(Name + Ext).str(), U16NameExt))
	return EC;

	Len = ::SearchPathW(Path, c_str(U16NameExt), nullptr,
	U16Result.capacity(), U16Result.data(), nullptr);
	} while (Len > U16Result.capacity());

	if (Len != 0)
	break; // Found it.
	}

	if (Len == 0)
	return mapWindowsError(::GetLastError());

	U16Result.set_size(Len);

	SmallVector<char, MAX_PATH> U8Result;
	if (std::error_code EC =
	windows::UTF16ToUTF8(U16Result.data(), U16Result.size(), U8Result))
	return EC;

	return std::string(U8Result.begin(), U8Result.end());
	}

	bool MakeErrMsg(std::string *ErrMsg, const std::string &prefix) {
	if (!ErrMsg)
	return true;
	char *buffer = NULL;
	DWORD LastError = GetLastError();
	DWORD R = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER \|
	FORMAT_MESSAGE_FROM_SYSTEM \|
	FORMAT_MESSAGE_MAX_WIDTH_MASK,
	NULL, LastError, 0, (LPSTR)&buffer, 1, NULL);
	if (R)
	*ErrMsg = prefix + ": " + buffer;
	else
	*ErrMsg = prefix + ": Unknown error";
	*ErrMsg += " (0x" + llvm::utohexstr(LastError) + ")";

	LocalFree(buffer);
	return R != 0;
	}

	static HANDLE RedirectIO(Optional<StringRef> Path, int fd,
	std::string *ErrMsg) {
	HANDLE h;
	if (!Path) {
	if (!DuplicateHandle(GetCurrentProcess(), (HANDLE)_get_osfhandle(fd),
	GetCurrentProcess(), &h,
	0, TRUE, DUPLICATE_SAME_ACCESS))
	return INVALID_HANDLE_VALUE;
	return h;
	}

	std::string fname;
	if (Path->empty())
	fname = "NUL";
	else
	fname = *Path;

	SECURITY_ATTRIBUTES sa;
	sa.nLength = sizeof(sa);
	sa.lpSecurityDescriptor = 0;
	sa.bInheritHandle = TRUE;

	SmallVector<wchar_t, 128> fnameUnicode;
	if (Path->empty()) {
	// Don't play long-path tricks on "NUL".
	if (windows::UTF8ToUTF16(fname, fnameUnicode))
	return INVALID_HANDLE_VALUE;
	} else {
	if (path::widenPath(fname, fnameUnicode))
	return INVALID_HANDLE_VALUE;
	}
	h = CreateFileW(fnameUnicode.data(), fd ? GENERIC_WRITE : GENERIC_READ,
	FILE_SHARE_READ, &sa, fd == 0 ? OPEN_EXISTING : CREATE_ALWAYS,
	FILE_ATTRIBUTE_NORMAL, NULL);
	if (h == INVALID_HANDLE_VALUE) {
	MakeErrMsg(ErrMsg, fname + ": Can't open file for " +
	(fd ? "input" : "output"));
	}

	return h;
	}

	}

	static bool Execute(ProcessInfo &PI, StringRef Program,
	ArrayRef<StringRef> Args, Optional<ArrayRef<StringRef>> Env,
	ArrayRef<Optional<StringRef>> Redirects,
	unsigned MemoryLimit, std::string *ErrMsg) {
	if (!sys::fs::can_execute(Program)) {
	if (ErrMsg)
	*ErrMsg = "program not executable";
	return false;
	}

	// can_execute may succeed by looking at Program + ".exe". CreateProcessW
	// will implicitly add the .exe if we provide a command line without an
	// executable path, but since we use an explicit executable, we have to add
	// ".exe" ourselves.
	SmallString<64> ProgramStorage;
	if (!sys::fs::exists(Program))
	Program = Twine(Program + ".exe").toStringRef(ProgramStorage);

	// Windows wants a command line, not an array of args, to pass to the new
	// process. We have to concatenate them all, while quoting the args that
	// have embedded spaces (or are empty).
	std::string Command = flattenWindowsCommandLine(Args);

	// The pointer to the environment block for the new process.
	std::vector<wchar_t> EnvBlock;

	if (Env) {
	// An environment block consists of a null-terminated block of
	// null-terminated strings. Convert the array of environment variables to
	// an environment block by concatenating them.
	for (const auto E : *Env) {
	SmallVector<wchar_t, MAX_PATH> EnvString;
	if (std::error_code ec = windows::UTF8ToUTF16(E, EnvString)) {
	SetLastError(ec.value());
	MakeErrMsg(ErrMsg, "Unable to convert environment variable to UTF-16");
	return false;
	}

	EnvBlock.insert(EnvBlock.end(), EnvString.begin(), EnvString.end());
	EnvBlock.push_back(0);
	}
	EnvBlock.push_back(0);
	}

	// Create a child process.
	STARTUPINFOW si;
	memset(&si, 0, sizeof(si));
	si.cb = sizeof(si);
	si.hStdInput = INVALID_HANDLE_VALUE;
	si.hStdOutput = INVALID_HANDLE_VALUE;
	si.hStdError = INVALID_HANDLE_VALUE;

	if (!Redirects.empty()) {
	si.dwFlags = STARTF_USESTDHANDLES;

	si.hStdInput = RedirectIO(Redirects[0], 0, ErrMsg);
	if (si.hStdInput == INVALID_HANDLE_VALUE) {
	MakeErrMsg(ErrMsg, "can't redirect stdin");
	return false;
	}
	si.hStdOutput = RedirectIO(Redirects[1], 1, ErrMsg);
	if (si.hStdOutput == INVALID_HANDLE_VALUE) {
	CloseHandle(si.hStdInput);
	MakeErrMsg(ErrMsg, "can't redirect stdout");
	return false;
	}
	if (Redirects[1] && Redirects[2] && Redirects[1] == Redirects[2]) {
	// If stdout and stderr should go to the same place, redirect stderr
	// to the handle already open for stdout.
	if (!DuplicateHandle(GetCurrentProcess(), si.hStdOutput,
	GetCurrentProcess(), &si.hStdError,
	0, TRUE, DUPLICATE_SAME_ACCESS)) {
	CloseHandle(si.hStdInput);
	CloseHandle(si.hStdOutput);
	MakeErrMsg(ErrMsg, "can't dup stderr to stdout");
	return false;
	}
	} else {
	// Just redirect stderr
	si.hStdError = RedirectIO(Redirects[2], 2, ErrMsg);
	if (si.hStdError == INVALID_HANDLE_VALUE) {
	CloseHandle(si.hStdInput);
	CloseHandle(si.hStdOutput);
	MakeErrMsg(ErrMsg, "can't redirect stderr");
	return false;
	}
	}
	}

	PROCESS_INFORMATION pi;
	memset(&pi, 0, sizeof(pi));

	fflush(stdout);
	fflush(stderr);

	SmallVector<wchar_t, MAX_PATH> ProgramUtf16;
	if (std::error_code ec = path::widenPath(Program, ProgramUtf16)) {
	SetLastError(ec.value());
	MakeErrMsg(ErrMsg,
	std::string("Unable to convert application name to UTF-16"));
	return false;
	}

	SmallVector<wchar_t, MAX_PATH> CommandUtf16;
	if (std::error_code ec = windows::UTF8ToUTF16(Command, CommandUtf16)) {
	SetLastError(ec.value());
	MakeErrMsg(ErrMsg,
	std::string("Unable to convert command-line to UTF-16"));
	return false;
	}

	BOOL rc = CreateProcessW(ProgramUtf16.data(), CommandUtf16.data(), 0, 0,
	TRUE, CREATE_UNICODE_ENVIRONMENT,
	EnvBlock.empty() ? 0 : EnvBlock.data(), 0, &si,
	&pi);
	DWORD err = GetLastError();

	// Regardless of whether the process got created or not, we are done with
	// the handles we created for it to inherit.
	CloseHandle(si.hStdInput);
	CloseHandle(si.hStdOutput);
	CloseHandle(si.hStdError);

	// Now return an error if the process didn't get created.
	if (!rc) {
	SetLastError(err);
	MakeErrMsg(ErrMsg, std::string("Couldn't execute program '") +
	Program.str() + "'");
	return false;
	}

	PI.Pid = pi.dwProcessId;
	PI.Process = pi.hProcess;

	// Make sure these get closed no matter what.
	ScopedCommonHandle hThread(pi.hThread);

	// Assign the process to a job if a memory limit is defined.
	ScopedJobHandle hJob;
	if (MemoryLimit != 0) {
	hJob = CreateJobObjectW(0, 0);
	bool success = false;
	if (hJob) {
	JOBOBJECT_EXTENDED_LIMIT_INFORMATION jeli;
	memset(&jeli, 0, sizeof(jeli));
	jeli.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_PROCESS_MEMORY;
	jeli.ProcessMemoryLimit = uintptr_t(MemoryLimit) * 1048576;
	if (SetInformationJobObject(hJob, JobObjectExtendedLimitInformation,
	&jeli, sizeof(jeli))) {
	if (AssignProcessToJobObject(hJob, pi.hProcess))
	success = true;
	}
	}
	if (!success) {
	SetLastError(GetLastError());
	MakeErrMsg(ErrMsg, std::string("Unable to set memory limit"));
	TerminateProcess(pi.hProcess, 1);
	WaitForSingleObject(pi.hProcess, INFINITE);
	return false;
	}
	}

	return true;
	}

	static bool argNeedsQuotes(StringRef Arg) {
	if (Arg.empty())
	return true;
	return StringRef::npos != Arg.find_first_of("\t \"&\'()*<>\\`^\|\n");
	}

	static std::string quoteSingleArg(StringRef Arg) {
	std::string Result;
	Result.push_back('"');

	while (!Arg.empty()) {
	size_t FirstNonBackslash = Arg.find_first_not_of('\\');
	size_t BackslashCount = FirstNonBackslash;
	if (FirstNonBackslash == StringRef::npos) {
	// The entire remainder of the argument is backslashes. Escape all of
	// them and just early out.
	BackslashCount = Arg.size();
	Result.append(BackslashCount * 2, '\\');
	break;
	}

	if (Arg[FirstNonBackslash] == '\"') {
	// This is an embedded quote. Escape all preceding backslashes, then
	// add one additional backslash to escape the quote.
	Result.append(BackslashCount * 2 + 1, '\\');
	Result.push_back('\"');
	} else {
	// This is just a normal character. Don't escape any of the preceding
	// backslashes, just append them as they are and then append the
	// character.
	Result.append(BackslashCount, '\\');
	Result.push_back(Arg[FirstNonBackslash]);
	}

	// Drop all the backslashes, plus the following character.
	Arg = Arg.drop_front(FirstNonBackslash + 1);
	}

	Result.push_back('"');
	return Result;
	}

	namespace llvm {
	std::string sys::flattenWindowsCommandLine(ArrayRef<StringRef> Args) {
	std::string Command;
	for (StringRef Arg : Args) {
	if (argNeedsQuotes(Arg))
	Command += quoteSingleArg(Arg);
	else
	Command += Arg;

	Command.push_back(' ');
	}

	return Command;
	}

	ProcessInfo sys::Wait(const ProcessInfo &PI, unsigned SecondsToWait,
	bool WaitUntilChildTerminates, std::string *ErrMsg) {
	assert(PI.Pid && "invalid pid to wait on, process not started?");
	assert((PI.Process && PI.Process != INVALID_HANDLE_VALUE) &&
	"invalid process handle to wait on, process not started?");
	DWORD milliSecondsToWait = 0;
	if (WaitUntilChildTerminates)
	milliSecondsToWait = INFINITE;
	else if (SecondsToWait > 0)
	milliSecondsToWait = SecondsToWait * 1000;

	ProcessInfo WaitResult = PI;
	DWORD WaitStatus = WaitForSingleObject(PI.Process, milliSecondsToWait);
	if (WaitStatus == WAIT_TIMEOUT) {
	if (SecondsToWait) {
	if (!TerminateProcess(PI.Process, 1)) {
	if (ErrMsg)
	MakeErrMsg(ErrMsg, "Failed to terminate timed-out program");

	// -2 indicates a crash or timeout as opposed to failure to execute.
	WaitResult.ReturnCode = -2;
	CloseHandle(PI.Process);
	return WaitResult;
	}
	WaitForSingleObject(PI.Process, INFINITE);
	CloseHandle(PI.Process);
	} else {
	// Non-blocking wait.
	return ProcessInfo();
	}
	}

	// Get its exit status.
	DWORD status;
	BOOL rc = GetExitCodeProcess(PI.Process, &status);
	DWORD err = GetLastError();
	if (err != ERROR_INVALID_HANDLE)
	CloseHandle(PI.Process);

	if (!rc) {
	SetLastError(err);
	if (ErrMsg)
	MakeErrMsg(ErrMsg, "Failed getting status for program");

	// -2 indicates a crash or timeout as opposed to failure to execute.
	WaitResult.ReturnCode = -2;
	return WaitResult;
	}

	if (!status)
	return WaitResult;

	// Pass 10(Warning) and 11(Error) to the callee as negative value.
	if ((status & 0xBFFF0000U) == 0x80000000U)
	WaitResult.ReturnCode = static_cast<int>(status);
	else if (status & 0xFF)
	WaitResult.ReturnCode = status & 0x7FFFFFFF;
	else
	WaitResult.ReturnCode = 1;

	return WaitResult;
	}

	std::error_code sys::ChangeStdinToBinary() {
	int result = _setmode(_fileno(stdin), _O_BINARY);
	if (result == -1)
	return std::error_code(errno, std::generic_category());
	return std::error_code();
	}

	std::error_code sys::ChangeStdoutToBinary() {
	int result = _setmode(_fileno(stdout), _O_BINARY);
	if (result == -1)
	return std::error_code(errno, std::generic_category());
	return std::error_code();
	}

	std::error_code
	llvm::sys::writeFileWithEncoding(StringRef FileName, StringRef Contents,
	WindowsEncodingMethod Encoding) {
	std::error_code EC;
	llvm::raw_fd_ostream OS(FileName, EC, llvm::sys::fs::F_Text);
	if (EC)
	return EC;

	if (Encoding == WEM_UTF8) {
	OS << Contents;
	} else if (Encoding == WEM_CurrentCodePage) {
	SmallVector<wchar_t, 1> ArgsUTF16;
	SmallVector<char, 1> ArgsCurCP;

	if ((EC = windows::UTF8ToUTF16(Contents, ArgsUTF16)))
	return EC;

	if ((EC = windows::UTF16ToCurCP(
	ArgsUTF16.data(), ArgsUTF16.size(), ArgsCurCP)))
	return EC;

	OS.write(ArgsCurCP.data(), ArgsCurCP.size());
	} else if (Encoding == WEM_UTF16) {
	SmallVector<wchar_t, 1> ArgsUTF16;

	if ((EC = windows::UTF8ToUTF16(Contents, ArgsUTF16)))
	return EC;

	// Endianness guessing
	char BOM[2];
	uint16_t src = UNI_UTF16_BYTE_ORDER_MARK_NATIVE;
	memcpy(BOM, &src, 2);
	OS.write(BOM, 2);
	OS.write((char *)ArgsUTF16.data(), ArgsUTF16.size() << 1);
	} else {
	llvm_unreachable("Unknown encoding");
	}

	if (OS.has_error())
	return make_error_code(errc::io_error);

	return EC;
	}

	bool llvm::sys::commandLineFitsWithinSystemLimits(StringRef Program,
	ArrayRef<StringRef> Args) {
	// The documented max length of the command line passed to CreateProcess.
	static const size_t MaxCommandStringLength = 32768;
	SmallVector<StringRef, 8> FullArgs;
	FullArgs.push_back(Program);
	FullArgs.append(Args.begin(), Args.end());
	std::string Result = flattenWindowsCommandLine(FullArgs);
	return (Result.size() + 1) <= MaxCommandStringLength;
	}
	}