1 files changed, 744 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/Driver/MSVCToolChain.cpp b/contrib/llvm/tools/clang/lib/Driver/MSVCToolChain.cpp
new file mode 100644
index 0000000..b7e576e
--- /dev/null
+++ b/contrib/llvm/tools/clang/lib/Driver/MSVCToolChain.cpp
@@ -0,0 +1,744 @@
+//===--- ToolChains.cpp - ToolChain Implementations -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ToolChains.h"
+#include "Tools.h"
+#include "clang/Basic/CharInfo.h"
+#include "clang/Basic/Version.h"
+#include "clang/Driver/Compilation.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Driver/DriverDiagnostic.h"
+#include "clang/Driver/Options.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Option/Arg.h"
+#include "llvm/Option/ArgList.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Process.h"
+#include <cstdio>
+
+// Include the necessary headers to interface with the Windows registry and
+// environment.
+#if defined(LLVM_ON_WIN32)
+#define USE_WIN32
+#endif
+
+#ifdef USE_WIN32
+  #define WIN32_LEAN_AND_MEAN
+  #define NOGDI
+  #ifndef NOMINMAX
+    #define NOMINMAX
+  #endif
+  #include <windows.h>
+#endif
+
+using namespace clang::driver;
+using namespace clang::driver::toolchains;
+using namespace clang;
+using namespace llvm::opt;
+
+MSVCToolChain::MSVCToolChain(const Driver &D, const llvm::Triple& Triple,
+                             const ArgList &Args)
+  : ToolChain(D, Triple, Args) {
+  getProgramPaths().push_back(getDriver().getInstalledDir());
+  if (getDriver().getInstalledDir() != getDriver().Dir)
+    getProgramPaths().push_back(getDriver().Dir);
+}
+
+Tool *MSVCToolChain::buildLinker() const {
+  return new tools::visualstudio::Linker(*this);
+}
+
+Tool *MSVCToolChain::buildAssembler() const {
+  if (getTriple().isOSBinFormatMachO())
+    return new tools::darwin::Assembler(*this);
+  getDriver().Diag(clang::diag::err_no_external_assembler);
+  return nullptr;
+}
+
+bool MSVCToolChain::IsIntegratedAssemblerDefault() const {
+  return true;
+}
+
+bool MSVCToolChain::IsUnwindTablesDefault() const {
+  // Emit unwind tables by default on Win64. All non-x86_32 Windows platforms
+  // such as ARM and PPC actually require unwind tables, but LLVM doesn't know
+  // how to generate them yet.
+  return getArch() == llvm::Triple::x86_64;
+}
+
+bool MSVCToolChain::isPICDefault() const {
+  return getArch() == llvm::Triple::x86_64;
+}
+
+bool MSVCToolChain::isPIEDefault() const {
+  return false;
+}
+
+bool MSVCToolChain::isPICDefaultForced() const {
+  return getArch() == llvm::Triple::x86_64;
+}
+
+#ifdef USE_WIN32
+static bool readFullStringValue(HKEY hkey, const char *valueName,
+                                std::string &value) {
+  // FIXME: We should be using the W versions of the registry functions, but
+  // doing so requires UTF8 / UTF16 conversions similar to how we handle command
+  // line arguments.  The UTF8 conversion functions are not exposed publicly
+  // from LLVM though, so in order to do this we will probably need to create
+  // a registry abstraction in LLVMSupport that is Windows only.
+  DWORD result = 0;
+  DWORD valueSize = 0;
+  DWORD type = 0;
+  // First just query for the required size.
+  result = RegQueryValueEx(hkey, valueName, NULL, &type, NULL, &valueSize);
+  if (result != ERROR_SUCCESS || type != REG_SZ)
+    return false;
+  std::vector<BYTE> buffer(valueSize);
+  result = RegQueryValueEx(hkey, valueName, NULL, NULL, &buffer[0], &valueSize);
+  if (result == ERROR_SUCCESS)
+    value.assign(reinterpret_cast<const char *>(buffer.data()));
+  return result;
+}
+#endif
+
+/// \brief Read registry string.
+/// This also supports a means to look for high-versioned keys by use
+/// of a $VERSION placeholder in the key path.
+/// $VERSION in the key path is a placeholder for the version number,
+/// causing the highest value path to be searched for and used.
+/// I.e. "SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
+/// There can be additional characters in the component.  Only the numeric
+/// characters are compared.  This function only searches HKLM.
+static bool getSystemRegistryString(const char *keyPath, const char *valueName,
+                                    std::string &value, std::string *phValue) {
+#ifndef USE_WIN32
+  return false;
+#else
+  HKEY hRootKey = HKEY_LOCAL_MACHINE;
+  HKEY hKey = NULL;
+  long lResult;
+  bool returnValue = false;
+
+  const char *placeHolder = strstr(keyPath, "$VERSION");
+  std::string bestName;
+  // If we have a $VERSION placeholder, do the highest-version search.
+  if (placeHolder) {
+    const char *keyEnd = placeHolder - 1;
+    const char *nextKey = placeHolder;
+    // Find end of previous key.
+    while ((keyEnd > keyPath) && (*keyEnd != '\\'))
+      keyEnd--;
+    // Find end of key containing $VERSION.
+    while (*nextKey && (*nextKey != '\\'))
+      nextKey++;
+    size_t partialKeyLength = keyEnd - keyPath;
+    char partialKey[256];
+    if (partialKeyLength > sizeof(partialKey))
+      partialKeyLength = sizeof(partialKey);
+    strncpy(partialKey, keyPath, partialKeyLength);
+    partialKey[partialKeyLength] = '\0';
+    HKEY hTopKey = NULL;
+    lResult = RegOpenKeyEx(hRootKey, partialKey, 0, KEY_READ | KEY_WOW64_32KEY,
+                           &hTopKey);
+    if (lResult == ERROR_SUCCESS) {
+      char keyName[256];
+      double bestValue = 0.0;
+      DWORD index, size = sizeof(keyName) - 1;
+      for (index = 0; RegEnumKeyEx(hTopKey, index, keyName, &size, NULL,
+          NULL, NULL, NULL) == ERROR_SUCCESS; index++) {
+        const char *sp = keyName;
+        while (*sp && !isDigit(*sp))
+          sp++;
+        if (!*sp)
+          continue;
+        const char *ep = sp + 1;
+        while (*ep && (isDigit(*ep) || (*ep == '.')))
+          ep++;
+        char numBuf[32];
+        strncpy(numBuf, sp, sizeof(numBuf) - 1);
+        numBuf[sizeof(numBuf) - 1] = '\0';
+        double dvalue = strtod(numBuf, NULL);
+        if (dvalue > bestValue) {
+          // Test that InstallDir is indeed there before keeping this index.
+          // Open the chosen key path remainder.
+          bestName = keyName;
+          // Append rest of key.
+          bestName.append(nextKey);
+          lResult = RegOpenKeyEx(hTopKey, bestName.c_str(), 0,
+                                 KEY_READ | KEY_WOW64_32KEY, &hKey);
+          if (lResult == ERROR_SUCCESS) {
+            lResult = readFullStringValue(hKey, valueName, value);
+            if (lResult == ERROR_SUCCESS) {
+              bestValue = dvalue;
+              if (phValue)
+                *phValue = bestName;
+              returnValue = true;
+            }
+            RegCloseKey(hKey);
+          }
+        }
+        size = sizeof(keyName) - 1;
+      }
+      RegCloseKey(hTopKey);
+    }
+  } else {
+    lResult =
+        RegOpenKeyEx(hRootKey, keyPath, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
+    if (lResult == ERROR_SUCCESS) {
+      lResult = readFullStringValue(hKey, valueName, value);
+      if (lResult == ERROR_SUCCESS)
+        returnValue = true;
+      if (phValue)
+        phValue->clear();
+      RegCloseKey(hKey);
+    }
+  }
+  return returnValue;
+#endif // USE_WIN32
+}
+
+// Convert LLVM's ArchType
+// to the corresponding name of Windows SDK libraries subfolder
+static StringRef getWindowsSDKArch(llvm::Triple::ArchType Arch) {
+  switch (Arch) {
+  case llvm::Triple::x86:
+    return "x86";
+  case llvm::Triple::x86_64:
+    return "x64";
+  case llvm::Triple::arm:
+    return "arm";
+  default:
+    return "";
+  }
+}
+
+// Find the most recent version of Universal CRT or Windows 10 SDK.
+// vcvarsqueryregistry.bat from Visual Studio 2015 sorts entries in the include
+// directory by name and uses the last one of the list.
+// So we compare entry names lexicographically to find the greatest one.
+static bool getWindows10SDKVersion(const std::string &SDKPath,
+                                   std::string &SDKVersion) {
+  SDKVersion.clear();
+
+  std::error_code EC;
+  llvm::SmallString<128> IncludePath(SDKPath);
+  llvm::sys::path::append(IncludePath, "Include");
+  for (llvm::sys::fs::directory_iterator DirIt(IncludePath, EC), DirEnd;
+       DirIt != DirEnd && !EC; DirIt.increment(EC)) {
+    if (!llvm::sys::fs::is_directory(DirIt->path()))
+      continue;
+    StringRef CandidateName = llvm::sys::path::filename(DirIt->path());
+    // If WDK is installed, there could be subfolders like "wdf" in the
+    // "Include" directory.
+    // Allow only directories which names start with "10.".
+    if (!CandidateName.startswith("10."))
+      continue;
+    if (CandidateName > SDKVersion)
+      SDKVersion = CandidateName;
+  }
+
+  return !SDKVersion.empty();
+}
+
+/// \brief Get Windows SDK installation directory.
+bool MSVCToolChain::getWindowsSDKDir(std::string &Path, int &Major,
+                                     std::string &WindowsSDKIncludeVersion,
+                                     std::string &WindowsSDKLibVersion) const {
+  std::string RegistrySDKVersion;
+  // Try the Windows registry.
+  if (!getSystemRegistryString(
+          "SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
+          "InstallationFolder", Path, &RegistrySDKVersion))
+    return false;
+  if (Path.empty() || RegistrySDKVersion.empty())
+    return false;
+
+  WindowsSDKIncludeVersion.clear();
+  WindowsSDKLibVersion.clear();
+  Major = 0;
+  std::sscanf(RegistrySDKVersion.c_str(), "v%d.", &Major);
+  if (Major <= 7)
+    return true;
+  if (Major == 8) {
+    // Windows SDK 8.x installs libraries in a folder whose names depend on the
+    // version of the OS you're targeting.  By default choose the newest, which
+    // usually corresponds to the version of the OS you've installed the SDK on.
+    const char *Tests[] = {"winv6.3", "win8", "win7"};
+    for (const char *Test : Tests) {
+      llvm::SmallString<128> TestPath(Path);
+      llvm::sys::path::append(TestPath, "Lib", Test);
+      if (llvm::sys::fs::exists(TestPath.c_str())) {
+        WindowsSDKLibVersion = Test;
+        break;
+      }
+    }
+    return !WindowsSDKLibVersion.empty();
+  }
+  if (Major == 10) {
+    if (!getWindows10SDKVersion(Path, WindowsSDKIncludeVersion))
+      return false;
+    WindowsSDKLibVersion = WindowsSDKIncludeVersion;
+    return true;
+  }
+  // Unsupported SDK version
+  return false;
+}
+
+// Gets the library path required to link against the Windows SDK.
+bool MSVCToolChain::getWindowsSDKLibraryPath(std::string &path) const {
+  std::string sdkPath;
+  int sdkMajor = 0;
+  std::string windowsSDKIncludeVersion;
+  std::string windowsSDKLibVersion;
+
+  path.clear();
+  if (!getWindowsSDKDir(sdkPath, sdkMajor, windowsSDKIncludeVersion,
+                        windowsSDKLibVersion))
+    return false;
+
+  llvm::SmallString<128> libPath(sdkPath);
+  llvm::sys::path::append(libPath, "Lib");
+  if (sdkMajor <= 7) {
+    switch (getArch()) {
+    // In Windows SDK 7.x, x86 libraries are directly in the Lib folder.
+    case llvm::Triple::x86:
+      break;
+    case llvm::Triple::x86_64:
+      llvm::sys::path::append(libPath, "x64");
+      break;
+    case llvm::Triple::arm:
+      // It is not necessary to link against Windows SDK 7.x when targeting ARM.
+      return false;
+    default:
+      return false;
+    }
+  } else {
+    const StringRef archName = getWindowsSDKArch(getArch());
+    if (archName.empty())
+      return false;
+    llvm::sys::path::append(libPath, windowsSDKLibVersion, "um", archName);
+  }
+
+  path = libPath.str();
+  return true;
+}
+
+// Check if the Include path of a specified version of Visual Studio contains
+// specific header files. If not, they are probably shipped with Universal CRT.
+bool clang::driver::toolchains::MSVCToolChain::useUniversalCRT(
+    std::string &VisualStudioDir) const {
+  llvm::SmallString<128> TestPath(VisualStudioDir);
+  llvm::sys::path::append(TestPath, "VC\\include\\stdlib.h");
+
+  return !llvm::sys::fs::exists(TestPath);
+}
+
+bool MSVCToolChain::getUniversalCRTSdkDir(std::string &Path,
+                                          std::string &UCRTVersion) const {
+  // vcvarsqueryregistry.bat for Visual Studio 2015 queries the registry
+  // for the specific key "KitsRoot10". So do we.
+  if (!getSystemRegistryString(
+          "SOFTWARE\\Microsoft\\Windows Kits\\Installed Roots", "KitsRoot10",
+          Path, nullptr))
+    return false;
+
+  return getWindows10SDKVersion(Path, UCRTVersion);
+}
+
+bool MSVCToolChain::getUniversalCRTLibraryPath(std::string &Path) const {
+  std::string UniversalCRTSdkPath;
+  std::string UCRTVersion;
+
+  Path.clear();
+  if (!getUniversalCRTSdkDir(UniversalCRTSdkPath, UCRTVersion))
+    return false;
+
+  StringRef ArchName = getWindowsSDKArch(getArch());
+  if (ArchName.empty())
+    return false;
+
+  llvm::SmallString<128> LibPath(UniversalCRTSdkPath);
+  llvm::sys::path::append(LibPath, "Lib", UCRTVersion, "ucrt", ArchName);
+
+  Path = LibPath.str();
+  return true;
+}
+
+// Get the location to use for Visual Studio binaries.  The location priority
+// is: %VCINSTALLDIR% > %PATH% > newest copy of Visual Studio installed on
+// system (as reported by the registry).
+bool MSVCToolChain::getVisualStudioBinariesFolder(const char *clangProgramPath,
+                                                  std::string &path) const {
+  path.clear();
+
+  SmallString<128> BinDir;
+
+  // First check the environment variables that vsvars32.bat sets.
+  llvm::Optional<std::string> VcInstallDir =
+      llvm::sys::Process::GetEnv("VCINSTALLDIR");
+  if (VcInstallDir.hasValue()) {
+    BinDir = VcInstallDir.getValue();
+    llvm::sys::path::append(BinDir, "bin");
+  } else {
+    // Next walk the PATH, trying to find a cl.exe in the path.  If we find one,
+    // use that.  However, make sure it's not clang's cl.exe.
+    llvm::Optional<std::string> OptPath = llvm::sys::Process::GetEnv("PATH");
+    if (OptPath.hasValue()) {
+      const char EnvPathSeparatorStr[] = {llvm::sys::EnvPathSeparator, '\0'};
+      SmallVector<StringRef, 8> PathSegments;
+      llvm::SplitString(OptPath.getValue(), PathSegments, EnvPathSeparatorStr);
+
+      for (StringRef PathSegment : PathSegments) {
+        if (PathSegment.empty())
+          continue;
+
+        SmallString<128> FilePath(PathSegment);
+        llvm::sys::path::append(FilePath, "cl.exe");
+        if (llvm::sys::fs::can_execute(FilePath.c_str()) &&
+            !llvm::sys::fs::equivalent(FilePath.c_str(), clangProgramPath)) {
+          // If we found it on the PATH, use it exactly as is with no
+          // modifications.
+          path = PathSegment;
+          return true;
+        }
+      }
+    }
+
+    std::string installDir;
+    // With no VCINSTALLDIR and nothing on the PATH, if we can't find it in the
+    // registry then we have no choice but to fail.
+    if (!getVisualStudioInstallDir(installDir))
+      return false;
+
+    // Regardless of what binary we're ultimately trying to find, we make sure
+    // that this is a Visual Studio directory by checking for cl.exe.  We use
+    // cl.exe instead of other binaries like link.exe because programs such as
+    // GnuWin32 also have a utility called link.exe, so cl.exe is the least
+    // ambiguous.
+    BinDir = installDir;
+    llvm::sys::path::append(BinDir, "VC", "bin");
+    SmallString<128> ClPath(BinDir);
+    llvm::sys::path::append(ClPath, "cl.exe");
+
+    if (!llvm::sys::fs::can_execute(ClPath.c_str()))
+      return false;
+  }
+
+  if (BinDir.empty())
+    return false;
+
+  switch (getArch()) {
+  case llvm::Triple::x86:
+    break;
+  case llvm::Triple::x86_64:
+    llvm::sys::path::append(BinDir, "amd64");
+    break;
+  case llvm::Triple::arm:
+    llvm::sys::path::append(BinDir, "arm");
+    break;
+  default:
+    // Whatever this is, Visual Studio doesn't have a toolchain for it.
+    return false;
+  }
+  path = BinDir.str();
+  return true;
+}
+
+// Get Visual Studio installation directory.
+bool MSVCToolChain::getVisualStudioInstallDir(std::string &path) const {
+  // First check the environment variables that vsvars32.bat sets.
+  const char *vcinstalldir = getenv("VCINSTALLDIR");
+  if (vcinstalldir) {
+    path = vcinstalldir;
+    path = path.substr(0, path.find("\\VC"));
+    return true;
+  }
+
+  std::string vsIDEInstallDir;
+  std::string vsExpressIDEInstallDir;
+  // Then try the windows registry.
+  bool hasVCDir =
+      getSystemRegistryString("SOFTWARE\\Microsoft\\VisualStudio\\$VERSION",
+                              "InstallDir", vsIDEInstallDir, nullptr);
+  if (hasVCDir && !vsIDEInstallDir.empty()) {
+    path = vsIDEInstallDir.substr(0, vsIDEInstallDir.find("\\Common7\\IDE"));
+    return true;
+  }
+
+  bool hasVCExpressDir =
+      getSystemRegistryString("SOFTWARE\\Microsoft\\VCExpress\\$VERSION",
+                              "InstallDir", vsExpressIDEInstallDir, nullptr);
+  if (hasVCExpressDir && !vsExpressIDEInstallDir.empty()) {
+    path = vsExpressIDEInstallDir.substr(
+        0, vsIDEInstallDir.find("\\Common7\\IDE"));
+    return true;
+  }
+
+  // Try the environment.
+  const char *vs120comntools = getenv("VS120COMNTOOLS");
+  const char *vs100comntools = getenv("VS100COMNTOOLS");
+  const char *vs90comntools = getenv("VS90COMNTOOLS");
+  const char *vs80comntools = getenv("VS80COMNTOOLS");
+
+  const char *vscomntools = nullptr;
+
+  // Find any version we can
+  if (vs120comntools)
+    vscomntools = vs120comntools;
+  else if (vs100comntools)
+    vscomntools = vs100comntools;
+  else if (vs90comntools)
+    vscomntools = vs90comntools;
+  else if (vs80comntools)
+    vscomntools = vs80comntools;
+
+  if (vscomntools && *vscomntools) {
+    const char *p = strstr(vscomntools, "\\Common7\\Tools");
+    path = p ? std::string(vscomntools, p) : vscomntools;
+    return true;
+  }
+  return false;
+}
+
+void MSVCToolChain::AddSystemIncludeWithSubfolder(
+    const ArgList &DriverArgs, ArgStringList &CC1Args,
+    const std::string &folder, const Twine &subfolder1, const Twine &subfolder2,
+    const Twine &subfolder3) const {
+  llvm::SmallString<128> path(folder);
+  llvm::sys::path::append(path, subfolder1, subfolder2, subfolder3);
+  addSystemInclude(DriverArgs, CC1Args, path);
+}
+
+void MSVCToolChain::AddClangSystemIncludeArgs(const ArgList &DriverArgs,
+                                              ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdinc))
+    return;
+
+  if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
+    AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, getDriver().ResourceDir,
+                                  "include");
+  }
+
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc))
+    return;
+
+  // Honor %INCLUDE%. It should know essential search paths with vcvarsall.bat.
+  if (const char *cl_include_dir = getenv("INCLUDE")) {
+    SmallVector<StringRef, 8> Dirs;
+    StringRef(cl_include_dir)
+        .split(Dirs, ";", /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+    for (StringRef Dir : Dirs)
+      addSystemInclude(DriverArgs, CC1Args, Dir);
+    if (!Dirs.empty())
+      return;
+  }
+
+  std::string VSDir;
+
+  // When built with access to the proper Windows APIs, try to actually find
+  // the correct include paths first.
+  if (getVisualStudioInstallDir(VSDir)) {
+    AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, VSDir, "VC\\include");
+
+    if (useUniversalCRT(VSDir)) {
+      std::string UniversalCRTSdkPath;
+      std::string UCRTVersion;
+      if (getUniversalCRTSdkDir(UniversalCRTSdkPath, UCRTVersion)) {
+        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, UniversalCRTSdkPath,
+                                      "Include", UCRTVersion, "ucrt");
+      }
+    }
+
+    std::string WindowsSDKDir;
+    int major;
+    std::string windowsSDKIncludeVersion;
+    std::string windowsSDKLibVersion;
+    if (getWindowsSDKDir(WindowsSDKDir, major, windowsSDKIncludeVersion,
+                         windowsSDKLibVersion)) {
+      if (major >= 8) {
+        // Note: windowsSDKIncludeVersion is empty for SDKs prior to v10.
+        // Anyway, llvm::sys::path::append is able to manage it.
+        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
+                                      "include", windowsSDKIncludeVersion,
+                                      "shared");
+        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
+                                      "include", windowsSDKIncludeVersion,
+                                      "um");
+        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
+                                      "include", windowsSDKIncludeVersion,
+                                      "winrt");
+      } else {
+        AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
+                                      "include");
+      }
+    } else {
+      addSystemInclude(DriverArgs, CC1Args, VSDir);
+    }
+    return;
+  }
+
+  // As a fallback, select default install paths.
+  // FIXME: Don't guess drives and paths like this on Windows.
+  const StringRef Paths[] = {
+    "C:/Program Files/Microsoft Visual Studio 10.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 9.0/VC/PlatformSDK/Include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/include",
+    "C:/Program Files/Microsoft Visual Studio 8/VC/PlatformSDK/Include"
+  };
+  addSystemIncludes(DriverArgs, CC1Args, Paths);
+}
+
+void MSVCToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                                 ArgStringList &CC1Args) const {
+  // FIXME: There should probably be logic here to find libc++ on Windows.
+}
+
+std::string
+MSVCToolChain::ComputeEffectiveClangTriple(const ArgList &Args,
+                                           types::ID InputType) const {
+  std::string TripleStr =
+      ToolChain::ComputeEffectiveClangTriple(Args, InputType);
+  llvm::Triple Triple(TripleStr);
+  VersionTuple MSVT =
+      tools::visualstudio::getMSVCVersion(/*D=*/nullptr, Triple, Args,
+                                          /*IsWindowsMSVC=*/true);
+  if (MSVT.empty())
+    return TripleStr;
+
+  MSVT = VersionTuple(MSVT.getMajor(), MSVT.getMinor().getValueOr(0),
+                      MSVT.getSubminor().getValueOr(0));
+
+  if (Triple.getEnvironment() == llvm::Triple::MSVC) {
+    StringRef ObjFmt = Triple.getEnvironmentName().split('-').second;
+    if (ObjFmt.empty())
+      Triple.setEnvironmentName((Twine("msvc") + MSVT.getAsString()).str());
+    else
+      Triple.setEnvironmentName(
+          (Twine("msvc") + MSVT.getAsString() + Twine('-') + ObjFmt).str());
+  }
+  return Triple.getTriple();
+}
+
+SanitizerMask MSVCToolChain::getSupportedSanitizers() const {
+  SanitizerMask Res = ToolChain::getSupportedSanitizers();
+  Res |= SanitizerKind::Address;
+  return Res;
+}
+
+llvm::opt::DerivedArgList *
+MSVCToolChain::TranslateArgs(const llvm::opt::DerivedArgList &Args,
+                             const char *BoundArch) const {
+  DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());
+  const OptTable &Opts = getDriver().getOpts();
+
+  // /Oy and /Oy- only has an effect under X86-32.
+  bool SupportsForcingFramePointer = getArch() == llvm::Triple::x86;
+
+  // The -O[12xd] flag actually expands to several flags.  We must desugar the
+  // flags so that options embedded can be negated.  For example, the '-O2' flag
+  // enables '-Oy'.  Expanding '-O2' into its constituent flags allows us to
+  // correctly handle '-O2 -Oy-' where the trailing '-Oy-' disables a single
+  // aspect of '-O2'.
+  //
+  // Note that this expansion logic only applies to the *last* of '[12xd]'.
+
+  // First step is to search for the character we'd like to expand.
+  const char *ExpandChar = nullptr;
+  for (Arg *A : Args) {
+    if (!A->getOption().matches(options::OPT__SLASH_O))
+      continue;
+    StringRef OptStr = A->getValue();
+    for (size_t I = 0, E = OptStr.size(); I != E; ++I) {
+      const char &OptChar = *(OptStr.data() + I);
+      if (OptChar == '1' || OptChar == '2' || OptChar == 'x' || OptChar == 'd')
+        ExpandChar = OptStr.data() + I;
+    }
+  }
+
+  // The -O flag actually takes an amalgam of other options.  For example,
+  // '/Ogyb2' is equivalent to '/Og' '/Oy' '/Ob2'.
+  for (Arg *A : Args) {
+    if (!A->getOption().matches(options::OPT__SLASH_O)) {
+      DAL->append(A);
+      continue;
+    }
+
+    StringRef OptStr = A->getValue();
+    for (size_t I = 0, E = OptStr.size(); I != E; ++I) {
+      const char &OptChar = *(OptStr.data() + I);
+      switch (OptChar) {
+      default:
+        break;
+      case '1':
+      case '2':
+      case 'x':
+      case 'd':
+        if (&OptChar == ExpandChar) {
+          if (OptChar == 'd') {
+            DAL->AddFlagArg(A, Opts.getOption(options::OPT_O0));
+          } else {
+            if (OptChar == '1') {
+              DAL->AddJoinedArg(A, Opts.getOption(options::OPT_O), "s");
+            } else if (OptChar == '2' || OptChar == 'x') {
+              DAL->AddFlagArg(A, Opts.getOption(options::OPT_fbuiltin));
+              DAL->AddJoinedArg(A, Opts.getOption(options::OPT_O), "2");
+            }
+            if (SupportsForcingFramePointer)
+              DAL->AddFlagArg(A,
+                              Opts.getOption(options::OPT_fomit_frame_pointer));
+            if (OptChar == '1' || OptChar == '2')
+              DAL->AddFlagArg(A,
+                              Opts.getOption(options::OPT_ffunction_sections));
+          }
+        }
+        break;
+      case 'b':
+        if (I + 1 != E && isdigit(OptStr[I + 1]))
+          ++I;
+        break;
+      case 'g':
+        break;
+      case 'i':
+        if (I + 1 != E && OptStr[I + 1] == '-') {
+          ++I;
+          DAL->AddFlagArg(A, Opts.getOption(options::OPT_fno_builtin));
+        } else {
+          DAL->AddFlagArg(A, Opts.getOption(options::OPT_fbuiltin));
+        }
+        break;
+      case 's':
+        DAL->AddJoinedArg(A, Opts.getOption(options::OPT_O), "s");
+        break;
+      case 't':
+        DAL->AddJoinedArg(A, Opts.getOption(options::OPT_O), "2");
+        break;
+      case 'y': {
+        bool OmitFramePointer = true;
+        if (I + 1 != E && OptStr[I + 1] == '-') {
+          OmitFramePointer = false;
+          ++I;
+        }
+        if (SupportsForcingFramePointer) {
+          if (OmitFramePointer)
+            DAL->AddFlagArg(A,
+                            Opts.getOption(options::OPT_fomit_frame_pointer));
+          else
+            DAL->AddFlagArg(
+                A, Opts.getOption(options::OPT_fno_omit_frame_pointer));
+        }
+        break;
+      }
+      }
+    }
+  }
+  return DAL;
+}