AST,Basic: update support for process execution on Windows

Implement process launching on Windows to support macros.  Prefer to use
the LLVM types wherever possible.  The pipes are converted into file
descriptors as the types are internal to the process.  This allows us to
have similar paths on both sides and avoid having to drag in `Windows.h`
for the definition of `HANDLE`.  This is the core missing functionality
for Windows to support macros.

include/swift/AST/PluginRegistry.h

@@ -52,14 +52,13 @@ class LoadedExecutablePlugin {
 
   /// Represents the current process of the executable plugin.
   struct PluginProcess {
-    const llvm::sys::procid_t pid;
-    const int inputFileDescriptor;
-    const int outputFileDescriptor;
+    const llvm::sys::ProcessInfo process;
+    const int input;
+    const int output;
     bool isStale = false;
 
-    PluginProcess(llvm::sys::procid_t pid, int inputFileDescriptor,
-                  int outputFileDescriptor);
-
+    PluginProcess(llvm::sys::ProcessInfo process, int input, int output)
+        : process(process), input(input), output(output) {}
     ~PluginProcess();
 
     ssize_t write(const void *buf, size_t nbyte) const;
@@ -138,7 +137,8 @@ public:
     llvm::erase_value(onReconnect, fn);
   }
 
-  llvm::sys::procid_t getPid() { return Process->pid; }
+  llvm::sys::procid_t getPid() { return Process->process.Pid; }
+  llvm::sys::process_t getProcess() { return Process->process.Process; }
 
   NullTerminatedStringRef getExecutablePath() {
     return {ExecutablePath.c_str(), ExecutablePath.size()};

include/swift/Basic/Program.h

@@ -40,14 +40,12 @@ int ExecuteInPlace(const char *Program, const char **args,
                    const char **env = nullptr);
 
 struct ChildProcessInfo {
-  llvm::sys::procid_t Pid;
-  int WriteFileDescriptor;
-  int ReadFileDescriptor;
+  llvm::sys::ProcessInfo ProcessInfo;
+  int Write;
+  int Read;
 
-  ChildProcessInfo(llvm::sys::procid_t Pid, int WriteFileDescriptor,
-                   int ReadFileDescriptor)
-      : Pid(Pid), WriteFileDescriptor(WriteFileDescriptor),
-        ReadFileDescriptor(ReadFileDescriptor) {}
+  ChildProcessInfo(llvm::sys::ProcessInfo ProcessInfo, int Write, int Read)
+      : ProcessInfo(ProcessInfo), Write(Write), Read(Read) {}
 };
 
 /// This function executes the program using the argument provided.

lib/AST/PluginLoader.cpp

@@ -41,8 +41,13 @@ PluginRegistry *PluginLoader::getRegistry() {
 static StringRef pluginModuleNameStringFromPath(StringRef path) {
   // Plugin library must be named 'lib${module name}(.dylib|.so|.dll)'.
   // FIXME: Shared library prefix might be different between platforms.
+#if defined(_WIN32)
+  constexpr StringRef libPrefix{};
+  constexpr StringRef libSuffix = ".dll";
+#else
   constexpr StringRef libPrefix = "lib";
   constexpr StringRef libSuffix = LTDL_SHLIB_EXT;
+#endif
 
   StringRef filename = llvm::sys::path::filename(path);
   if (filename.starts_with(libPrefix) && filename.ends_with(libSuffix)) {

lib/AST/PluginRegistry.cpp

@@ -75,7 +75,9 @@ void *LoadedLibraryPlugin::getAddressOfSymbol(const char *symbolName) {
   auto &cached = resolvedSymbols[symbolName];
   if (cached)
     return cached;
-#if !defined(_WIN32)
+#if defined(_WIN32)
+  cached = GetProcAddress(static_cast<HMODULE>(handle), symbolName);
+#else
   cached = dlsym(handle, symbolName);
 #endif
   return cached;
@@ -153,9 +155,8 @@ llvm::Error LoadedExecutablePlugin::spawnIfNeeded() {
     return llvm::errorCodeToError(childInfo.getError());
   }
 
-  Process = std::make_unique<PluginProcess>(childInfo->Pid,
-                                            childInfo->ReadFileDescriptor,
-                                            childInfo->WriteFileDescriptor);
+  Process = std::make_unique<PluginProcess>(childInfo->ProcessInfo,
+                                            childInfo->Read, childInfo->Write);
 
   // Call "on reconnect" callbacks.
   for (auto *callback : onReconnect) {
@@ -165,15 +166,15 @@ llvm::Error LoadedExecutablePlugin::spawnIfNeeded() {
   return llvm::Error::success();
 }
 
-LoadedExecutablePlugin::PluginProcess::PluginProcess(llvm::sys::procid_t pid,
-                                                     int inputFileDescriptor,
-                                                     int outputFileDescriptor)
-    : pid(pid), inputFileDescriptor(inputFileDescriptor),
-      outputFileDescriptor(outputFileDescriptor) {}
-
 LoadedExecutablePlugin::PluginProcess::~PluginProcess() {
-  close(inputFileDescriptor);
-  close(outputFileDescriptor);
+#if defined(_WIN32)
+  _close(input);
+  _close(output);
+  CloseHandle(process.Process);
+#else
+  close(input);
+  close(output);
+#endif
 }
 
 LoadedExecutablePlugin::~LoadedExecutablePlugin() {
@@ -184,6 +185,17 @@ LoadedExecutablePlugin::~LoadedExecutablePlugin() {
 
 ssize_t LoadedExecutablePlugin::PluginProcess::read(void *buf,
                                                     size_t nbyte) const {
+#if defined(_WIN32)
+  size_t nread = 0;
+  while (nread < nbyte) {
+    int n = _read(input, static_cast<char*>(buf) + nread,
+                  std::min(static_cast<size_t>(UINT32_MAX), nbyte - nread));
+    if (n <= 0)
+      break;
+    nread += n;
+  }
+  return nread;
+#else
   ssize_t bytesToRead = nbyte;
   void *ptr = buf;
 
@@ -206,10 +218,22 @@ ssize_t LoadedExecutablePlugin::PluginProcess::read(void *buf,
   }
 
   return nbyte - bytesToRead;
+#endif
 }
 
 ssize_t LoadedExecutablePlugin::PluginProcess::write(const void *buf,
                                                      size_t nbyte) const {
+#if defined(_WIN32)
+  size_t nwritten = 0;
+  while (nwritten < nbyte) {
+    int n = _write(output, static_cast<const char *>(buf) + nwritten,
+                   std::min(static_cast<size_t>(UINT32_MAX), nbyte - nwritten));
+    if (n <= 0)
+      break;
+    nwritten += n;
+  }
+  return nwritten;
+#else
   ssize_t bytesToWrite = nbyte;
   const void *ptr = buf;
 
@@ -231,13 +255,14 @@ ssize_t LoadedExecutablePlugin::PluginProcess::write(const void *buf,
     bytesToWrite -= writtenSize;
   }
   return nbyte - bytesToWrite;
+#endif
 }
 
 llvm::Error LoadedExecutablePlugin::sendMessage(llvm::StringRef message) const {
   ssize_t writtenSize = 0;
 
   if (dumpMessaging) {
-    llvm::dbgs() << "->(plugin:" << Process->pid << ") " << message << "\n";
+    llvm::dbgs() << "->(plugin:" << Process->process.Pid << ") " << message << '\n';
   }
 
   const char *data = message.data();
@@ -297,7 +322,7 @@ llvm::Expected<std::string> LoadedExecutablePlugin::waitForNextMessage() const {
   }
 
   if (dumpMessaging) {
-    llvm::dbgs() << "<-(plugin:" << Process->pid << ") " << message << "\n";
+    llvm::dbgs() << "<-(plugin:" << Process->process.Pid << ") " << message << "\n";
   }
 
   return message;

lib/Basic/Program.cpp

@@ -18,7 +18,11 @@
 #include "llvm/Config/config.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Program.h"
+#if defined(_WIN32)
+#include "llvm/Support/Windows/WindowsSupport.h"
+#endif
 
+#include <memory>
 #include <system_error>
 
 #if HAVE_POSIX_SPAWN
@@ -29,6 +33,12 @@
 #include <unistd.h>
 #endif
 
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+#include <io.h>
+#endif
+
 using namespace swift;
 
 int swift::ExecuteInPlace(const char *Program, const char **args,
@@ -178,6 +188,97 @@ swift::ExecuteWithPipe(llvm::StringRef program,
   return ChildProcessInfo(pid, p1.write, p2.read);
 }
 
+#elif defined(_WIN32)
+
+llvm::ErrorOr<swift::ChildProcessInfo>
+swift::ExecuteWithPipe(llvm::StringRef program,
+                       llvm::ArrayRef<llvm::StringRef> args,
+                       llvm::Optional<llvm::ArrayRef<llvm::StringRef>> env) {
+  using unique_handle = std::unique_ptr<void, decltype(&CloseHandle)>;
+  enum { PI_READ, PI_WRITE };
+
+  unique_handle input[2] = {
+    {INVALID_HANDLE_VALUE, CloseHandle},
+    {INVALID_HANDLE_VALUE, CloseHandle},
+  };
+  unique_handle output[2] = {
+    {INVALID_HANDLE_VALUE, CloseHandle},
+    {INVALID_HANDLE_VALUE, CloseHandle},
+  };
+  unique_handle error{INVALID_HANDLE_VALUE, CloseHandle};
+  HANDLE hRead = INVALID_HANDLE_VALUE, hWrite = INVALID_HANDLE_VALUE;
+  SECURITY_ATTRIBUTES saAttrs{sizeof(SECURITY_ATTRIBUTES), NULL, TRUE};
+
+  if (!CreatePipe(&hRead, &hWrite, &saAttrs, 0))
+    return std::error_code(GetLastError(), std::system_category());
+  output[PI_READ].reset(hRead);
+  output[PI_WRITE].reset(hWrite);
+
+  if (!SetHandleInformation(output[PI_READ].get(), HANDLE_FLAG_INHERIT, FALSE))
+    return std::error_code(GetLastError(), std::system_category());
+
+  if (!CreatePipe(&hRead, &hWrite, &saAttrs, 0))
+    return std::error_code(GetLastError(), std::system_category());
+  input[PI_READ].reset(hRead);
+  input[PI_WRITE].reset(hWrite);
+
+  if (!SetHandleInformation(input[PI_WRITE].get(), HANDLE_FLAG_INHERIT, FALSE))
+    return std::error_code(GetLastError(), std::system_category());
+
+  if (!DuplicateHandle(GetCurrentProcess(), GetStdHandle(STD_ERROR_HANDLE),
+                       GetCurrentProcess(), &hWrite, DUPLICATE_SAME_ACCESS,
+                       TRUE, DUPLICATE_SAME_ACCESS))
+    return std::error_code(GetLastError(), std::system_category());
+  error.reset(hWrite);
+
+  STARTUPINFO si = {0};
+  si.cb = sizeof(si);
+  si.hStdInput = input[PI_READ].get();
+  si.hStdOutput = output[PI_WRITE].get();
+  si.hStdError = error.get();
+  si.dwFlags = STARTF_USESTDHANDLES;
+
+  llvm::SmallVector<wchar_t, MAX_PATH> executable;
+  if (std::error_code ec = llvm::sys::windows::widenPath(program, executable))
+    return ec;
+
+  std::vector<StringRef> components;
+  components.push_back(program);
+  components.assign(args.begin(), args.end());
+  llvm::ErrorOr<std::wstring> commandline =
+      llvm::sys::flattenWindowsCommandLine(components);
+  if (!commandline)
+    return commandline.getError();
+
+  std::vector<wchar_t> command(commandline->size() + 1, 0);
+  std::copy(commandline->begin(), commandline->end(), command.begin());
+
+  PROCESS_INFORMATION pi = {0};
+  if (!CreateProcessW(executable.data(),
+                      command.data(), nullptr, nullptr, TRUE, 0, nullptr,
+                      nullptr, &si, &pi))
+    return std::error_code(GetLastError(), std::system_category());
+
+  unique_handle hThread{pi.hThread, CloseHandle};
+  unique_handle hProcess{pi.hProcess, CloseHandle};
+
+  int ifd = _open_osfhandle(reinterpret_cast<intptr_t>(input[PI_WRITE].get()), 0);
+  if (ifd < 0)
+    return std::error_code(errno, std::system_category());
+  input[PI_WRITE].release();
+
+  int ofd = _open_osfhandle(reinterpret_cast<intptr_t>(output[PI_READ].get()), 0);
+  if (ofd < 0) {
+    _close(ifd);
+    return std::error_code(errno, std::system_category());
+  }
+  output[PI_READ].release();
+
+  llvm::sys::ProcessInfo proc;
+  proc.Process = pi.hProcess;
+  return ChildProcessInfo(proc, ifd, ofd);
+}
+
 #else // HAVE_UNISTD_H
 
 llvm::ErrorOr<swift::ChildProcessInfo>