Update clang-cl driver for MSVC 2017

[zturner]

Summary

This patch is originally based on D28365, but the clang ToolChain code has been significantly refactored since then, so rebasing that patch on top of tip was difficult / impossible. In any case, I got all of the changes integrated over here, with one notable difference: The header file containing all of the GUIDs and interface definitions is checked directly into the repository. This way it "just works", and we don't have to worry about if the required header file is present, and more importantly, copies of clang built with VS 2015 can run on a machine with VS 2017 installed and still properly detect the VS 2017 install. This would not be possible otherwise. I've added dberlin as a reviewer for the portion of this CL that involves checking in the header file.

[rnk]

lgtm

[• dberlin]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

There is no project root, you should paste the LICENSE.txt into the header directly.
Also, generally, i would segregate this into a third_party directory, as keeping code like this directly in the rest of the project makes it a lot messier

[zturner]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

Is a third_party directory directly in this folder ok, or should it be some kind of top level third_party directory?

[• dberlin]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

Normal practice for our open source projects (ie not llvm) would be top-level, because otherwise they tend to be hard to notice.
Again, unsure what llvm wants the policy to be here.

[majnemer]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

LLVM, in typical practice, does not segregate small amounts of third party code.

For example:
https://github.com/llvm-mirror/llvm/blob/a93bc6c25340329e49407f5fc231ca870f5c61e3/include/llvm/Support/MD5.h
https://github.com/llvm-mirror/llvm/blob/a93bc6c25340329e49407f5fc231ca870f5c61e3/include/llvm/Support/SHA1.h#L9
https://github.com/llvm-mirror/llvm/blob/a93bc6c25340329e49407f5fc231ca870f5c61e3/include/llvm/Support/xxhash.h

[• dberlin]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

FWIW, this is likely a remarkably bad idea :)
But i'll email the foundation folks and see what they think.

[zturner]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

Given that there's already precedent for doing de-segregating (is that the right word here?) small pieces of 3rd party code, is it ok for this to go in as-is (after pasting the LICENSE.txt into the header) and then after the foundation reaches a decision, we come back and address it all at once?

[• dberlin]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

I'm not going to approve it, since i think making the problem worse is also a really bad idea, but if someone else does, and you commit it, i'm not going to take offense.

[zturner]

clang/lib/Driver/ToolChains/MSVCSetupApi.h

3

How about this then? For now, I will assume that if _MSC_VER >= 1910 (i.e. you are building with VS 2017), then you also have the Microsoft header, and I will include the Microsoft header and this codepath will work. Otherwise, you get the old codepath (meaning that if you build clang with MSVC <2017, then you also cannot use the built clang to achieve compatibility with MSVC 2017 even if you copy it to a machine that has MSVC 2017 installed.)

Once you hear back and reach a decision, we can get this header checked in and enable clang-cl bootstrapped with MSVC 2015 to be compatible with MSVC >= 2017.

[hamzasood]

I don't think any Visual Studio versions ship with the header, it needs to be installed via Nuget

[zturner]

In D30758#700673, @hamzasood wrote:

I don't think any Visual Studio versions ship with the header, it needs to be installed via Nuget

Yea I realized that when I removed the header locally and tried to find the one to include. That's a bummer.

clang/include/clang/Basic/DiagnosticDriverKinds.td

 
 def warn_drv_ps4_sdk_dir : Warning<
   "environment variable SCE_ORBIS_SDK_DIR is set, but points to invalid or nonexistent directory '%0'">,
   InGroup<InvalidOrNonExistentDirectory>;
 
 def err_drv_unsupported_linker : Error<"unsupported value '%0' for -linker option">;
 def err_drv_defsym_invalid_format : Error<"defsym must be of the form: sym=value: %0">;
 def err_drv_defsym_invalid_symval : Error<"Value is not an integer: %0">;
+def warn_drv_msvc_not_found : Warning<
+  "unable to find a Visual Studio installation; "
+  "try running Clang from a developer command prompt">,
+  InGroup<InvalidOrNonExistentDirectory>;
 }

clang/lib/Driver/ToolChains/MSVC.h

TranslateArgs(const llvm::opt::DerivedArgList &Args, StringRef BoundArch,
                 Action::OffloadKind DeviceOffloadKind) const override;
 
   bool IsIntegratedAssemblerDefault() const override;
   bool IsUnwindTablesDefault() const override;
   bool isPICDefault() const override;
   bool isPIEDefault() const override;
   bool isPICDefaultForced() const override;
 
+  enum class SubDirectoryType {
+    Bin,
+    Include,
+    Lib,
+  };
+  std::string getSubDirectoryPath(SubDirectoryType Type,
+                                  llvm::Triple::ArchType TargetArch) const;
+
+  // Convenience overload.
+  // Uses the current target arch.
+  std::string getSubDirectoryPath(SubDirectoryType Type) const {
+    return getSubDirectoryPath(Type, getArch());
+  }
+
+  bool getIsVS2017OrNewer() const { return IsVS2017OrNewer; }
+
   void
   AddClangSystemIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                             llvm::opt::ArgStringList &CC1Args) const override;
   void AddClangCXXStdlibIncludeArgs(
       const llvm::opt::ArgList &DriverArgs,
       llvm::opt::ArgStringList &CC1Args) const override;
 
   void AddCudaIncludeArgs(const llvm::opt::ArgList &DriverArgs,
                           llvm::opt::ArgStringList &CC1Args) const override;
 
-  bool getWindowsSDKDir(std::string &path, int &major,
-                        std::string &windowsSDKIncludeVersion,
-                        std::string &windowsSDKLibVersion) const;
   bool getWindowsSDKLibraryPath(std::string &path) const;
   /// \brief Check if Universal CRT should be used if available
-  bool useUniversalCRT(std::string &visualStudioDir) const;
-  bool getUniversalCRTSdkDir(std::string &path, std::string &ucrtVersion) const;
   bool getUniversalCRTLibraryPath(std::string &path) const;
-  bool getVisualStudioInstallDir(std::string &path) const;
-  bool getVisualStudioBinariesFolder(const char *clangProgramPath,
-                                     std::string &path) const;
+  bool useUniversalCRT() const;
   VersionTuple
   computeMSVCVersion(const Driver *D,
                      const llvm::opt::ArgList &Args) const override;
 
   std::string ComputeEffectiveClangTriple(const llvm::opt::ArgList &Args,
                                           types::ID InputType) const override;
   SanitizerMask getSupportedSanitizers() const override;
 
   void printVerboseInfo(raw_ostream &OS) const override;
 
 protected:
   void AddSystemIncludeWithSubfolder(const llvm::opt::ArgList &DriverArgs,
                                      llvm::opt::ArgStringList &CC1Args,
                                      const std::string &folder,
                                      const Twine &subfolder1,
                                      const Twine &subfolder2 = "",
                                      const Twine &subfolder3 = "") const;
 
   Tool *buildLinker() const override;
   Tool *buildAssembler() const override;
 private:
-  VersionTuple getMSVCVersionFromTriple() const;
-  VersionTuple getMSVCVersionFromExe() const;
-
+  std::string VCToolChainPath;
+  bool IsVS2017OrNewer;
   CudaInstallationDetector CudaInstallation;
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_MSVC_H

clang/lib/Driver/ToolChains/MSVC.cpp

 //===--- 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 "Darwin.h"
 #include "MSVC.h"
 #include "CommonArgs.h"
+#include "Darwin.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 "clang/Driver/SanitizerArgs.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Option/Arg.h"
 #include "llvm/Option/ArgList.h"
 #include "llvm/Support/ConvertUTF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/Path.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>
+
+// Make sure this comes before MSVCSetupApi.h
+#include <comdef.h>
+
+#include "MSVCSetupApi.h"
+#include "llvm/Support/COM.h"
+_COM_SMARTPTR_TYPEDEF(ISetupConfiguration, __uuidof(ISetupConfiguration));
+_COM_SMARTPTR_TYPEDEF(ISetupConfiguration2, __uuidof(ISetupConfiguration2));
+_COM_SMARTPTR_TYPEDEF(ISetupHelper, __uuidof(ISetupHelper));
+_COM_SMARTPTR_TYPEDEF(IEnumSetupInstances, __uuidof(IEnumSetupInstances));
+_COM_SMARTPTR_TYPEDEF(ISetupInstance, __uuidof(ISetupInstance));
+_COM_SMARTPTR_TYPEDEF(ISetupInstance2, __uuidof(ISetupInstance2));
 #endif
 
 using namespace clang::driver;
 using namespace clang::driver::toolchains;
 using namespace clang::driver::tools;
 using namespace clang;
 using namespace llvm::opt;
 
+// Defined below.
+// Forward declare this so there aren't too many things above the constructor.
+static bool getSystemRegistryString(const char *keyPath, const char *valueName,
+                                    std::string &value, std::string *phValue);
+
+// Check various environment variables to try and find a toolchain.
+static bool findVCToolChainViaEnvironment(std::string &Path,
+                                          bool &IsVS2017OrNewer) {
+  // These variables are typically set by vcvarsall.bat
+  // when launching a developer command prompt.
+  if (llvm::Optional<std::string> VCToolsInstallDir =
+          llvm::sys::Process::GetEnv("VCToolsInstallDir")) {
+    // This is only set by newer Visual Studios, and it leads straight to
+    // the toolchain directory.
+    Path = std::move(*VCToolsInstallDir);
+    IsVS2017OrNewer = true;
+    return true;
+  }
+  if (llvm::Optional<std::string> VCInstallDir =
+          llvm::sys::Process::GetEnv("VCINSTALLDIR")) {
+    // If the previous variable isn't set but this one is, then we've found
+    // an older Visual Studio. This variable is set by newer Visual Studios too,
+    // so this check has to appear second.
+    // In older Visual Studios, the VC directory is the toolchain.
+    Path = std::move(*VCInstallDir);
+    IsVS2017OrNewer = false;
+    return true;
+  }
+
+  // We couldn't find any VC environment variables. Let's walk through PATH and
+  // see if it leads us to a VC toolchain bin directory. If it does, pick the
+  // first one that we find.
+  if (llvm::Optional<std::string> PathEnv =
+          llvm::sys::Process::GetEnv("PATH")) {
+    llvm::SmallVector<llvm::StringRef, 8> PathEntries;
+    llvm::StringRef(*PathEnv).split(PathEntries, llvm::sys::EnvPathSeparator);
+    for (llvm::StringRef PathEntry : PathEntries) {
+      if (PathEntry.empty())
+        continue;
+
+      llvm::SmallString<256> ExeTestPath;
+
+      // If cl.exe doesn't exist, then this definitely isn't a VC toolchain.
+      ExeTestPath = PathEntry;
+      llvm::sys::path::append(ExeTestPath, "cl.exe");
+      if (!llvm::sys::fs::exists(ExeTestPath))
+        continue;
+
+      // cl.exe existing isn't a conclusive test for a VC toolchain; clang also
+      // has a cl.exe. So let's check for link.exe too.
+      ExeTestPath = PathEntry;
+      llvm::sys::path::append(ExeTestPath, "link.exe");
+      if (!llvm::sys::fs::exists(ExeTestPath))
+        continue;
+
+      // whatever/VC/bin --> old toolchain, VC dir is toolchain dir.
+      if (llvm::sys::path::filename(PathEntry) == "bin") {
+        llvm::StringRef ParentPath = llvm::sys::path::parent_path(PathEntry);
+        if (llvm::sys::path::filename(ParentPath) == "VC") {
+          Path = ParentPath;
+          IsVS2017OrNewer = false;
+          return true;
+        }
+
+      } else {
+        // This could be a new (>=VS2017) toolchain. If it is, we should find
+        // path components with these prefixes when walking backwards through
+        // the path.
+        // Note: empty strings match anything.
+        llvm::StringRef ExpectedPrefixes[] = {"",     "Host",  "bin", "",
+                                              "MSVC", "Tools", "VC"};
+
+        auto It = llvm::sys::path::rbegin(PathEntry);
+        auto End = llvm::sys::path::rend(PathEntry);
+        for (llvm::StringRef Prefix : ExpectedPrefixes) {
+          if (It == End)
+            goto NotAToolChain;
+          if (!It->startswith(Prefix))
+            goto NotAToolChain;
+          ++It;
+        }
+
+        // We've found a new toolchain!
+        // Back up 3 times (/bin/Host/arch) to get the root path.
+        llvm::StringRef ToolChainPath(PathEntry);
+        for (int i = 0; i < 3; ++i)
+          ToolChainPath = llvm::sys::path::parent_path(ToolChainPath);
+
+        Path = ToolChainPath;
+        IsVS2017OrNewer = true;
+        return true;
+      }
+
+    NotAToolChain:
+      continue;
+    }
+  }
+  return false;
+}
+
+// Query the Setup Config server for installs, then pick the newest version
+// and find its default VC toolchain.
+// This is the preferred way to discover new Visual Studios, as they're no
+// longer listed in the registry.
+static bool findVCToolChainViaSetupConfig(std::string &Path,
+                                          bool &IsVS2017OrNewer) {
+#if !defined(USE_WIN32)
+  return false;
+#else
+  // FIXME: This really should be done once in the top-level program's main
+  // function, as it may have already been initialized with a different
+  // threading model otherwise.
+  llvm::sys::InitializeCOMRAII COM(llvm::sys::COMThreadingMode::SingleThreaded);
+  HRESULT HR;
+
+  // _com_ptr_t will throw a _com_error if a COM calls fail.
+  // The LLVM coding standards forbid exception handling, so we'll have to
+  // stop them from being thrown in the first place.
+  // The destructor will put the regular error handler back when we leave
+  // this scope.
+  struct SuppressCOMErrorsRAII {
+    static void __stdcall handler(HRESULT hr, IErrorInfo *perrinfo) {}
+
+    SuppressCOMErrorsRAII() { _set_com_error_handler(handler); }
+
+    ~SuppressCOMErrorsRAII() { _set_com_error_handler(_com_raise_error); }
+
+  } COMErrorSuppressor;
+
+  ISetupConfigurationPtr Query;
+  HR = Query.CreateInstance(__uuidof(SetupConfiguration));
+  if (FAILED(HR))
+    return false;
+
+  IEnumSetupInstancesPtr EnumInstances;
+  HR = ISetupConfiguration2Ptr(Query)->EnumAllInstances(&EnumInstances);
+  if (FAILED(HR))
+    return false;
+
+  ISetupInstancePtr Instance;
+  HR = EnumInstances->Next(1, &Instance, nullptr);
+  if (HR != S_OK)
+    return false;
+
+  ISetupInstancePtr NewestInstance;
+  Optional<uint64_t> NewestVersionNum;
+  do {
+    bstr_t VersionString;
+    uint64_t VersionNum;
+    HR = Instance->GetInstallationVersion(VersionString.GetAddress());
+    if (FAILED(HR))
+      continue;
+    HR = ISetupHelperPtr(Query)->ParseVersion(VersionString, &VersionNum);
+    if (FAILED(HR))
+      continue;
+    if (!NewestVersionNum || (VersionNum > NewestVersionNum)) {
+      NewestInstance = Instance;
+      NewestVersionNum = VersionNum;
+    }
+  } while ((HR = EnumInstances->Next(1, &Instance, nullptr)) == S_OK);
+
+  if (!NewestInstance)
+    return false;
+
+  bstr_t VCPathWide;
+  HR = NewestInstance->ResolvePath(L"VC", VCPathWide.GetAddress());
+  if (FAILED(HR))
+    return false;
+
+  std::string VCRootPath;
+  llvm::convertWideToUTF8(std::wstring(VCPathWide), VCRootPath);
+
+  llvm::SmallString<256> ToolsVersionFilePath(VCRootPath);
+  llvm::sys::path::append(ToolsVersionFilePath, "Auxiliary", "Build",
+                          "Microsoft.VCToolsVersion.default.txt");
+
+  auto ToolsVersionFile = llvm::MemoryBuffer::getFile(ToolsVersionFilePath);
+  if (!ToolsVersionFile)
+    return false;
+
+  llvm::SmallString<256> ToolchainPath(VCRootPath);
+  llvm::sys::path::append(ToolchainPath, "Tools", "MSVC",
+                          ToolsVersionFile->get()->getBuffer().rtrim());
+  if (!llvm::sys::fs::is_directory(ToolchainPath))
+    return false;
+
+  Path = ToolchainPath.str();
+  IsVS2017OrNewer = true;
+  return true;
+#endif
+}
+
+// Look in the registry for Visual Studio installs, and use that to get
+// a toolchain path. VS2017 and newer don't get added to the registry.
+// So if we find something here, we know that it's an older version.
+static bool findVCToolChainViaRegistry(std::string &Path,
+                                       bool &IsVS2017OrNewer) {
+  std::string VSInstallPath;
+  if (getSystemRegistryString(R"(SOFTWARE\Microsoft\VisualStudio\$VERSION)",
+                              "InstallDir", VSInstallPath, nullptr) ||
+      getSystemRegistryString(R"(SOFTWARE\Microsoft\VCExpress\$VERSION)",
+                              "InstallDir", VSInstallPath, nullptr)) {
+    if (!VSInstallPath.empty()) {
+      llvm::SmallString<256> VCPath(llvm::StringRef(
+          VSInstallPath.c_str(), VSInstallPath.find(R"(\Common7\IDE)")));
+      llvm::sys::path::append(VCPath, "VC");
+
+      Path = VCPath.str();
+      IsVS2017OrNewer = false;
+      return true;
+    }
+  }
+  return false;
+}
+
 // Try to find Exe from a Visual Studio distribution.  This first tries to find
 // an installed copy of Visual Studio and, failing that, looks in the PATH,
 // making sure that whatever executable that's found is not a same-named exe
 // from clang itself to prevent clang from falling back to itself.
 static std::string FindVisualStudioExecutable(const ToolChain &TC,
-                                              const char *Exe,
-                                              const char *ClangProgramPath) {
+                                              const char *Exe) {
   const auto &MSVC = static_cast<const toolchains::MSVCToolChain &>(TC);
-  std::string visualStudioBinDir;
-  if (MSVC.getVisualStudioBinariesFolder(ClangProgramPath,
-                                         visualStudioBinDir)) {
-    SmallString<128> FilePath(visualStudioBinDir);
-    llvm::sys::path::append(FilePath, Exe);
-    if (llvm::sys::fs::can_execute(FilePath.c_str()))
-      return FilePath.str();
-  }
-
-  return Exe;
+  SmallString<128> FilePath(MSVC.getSubDirectoryPath(
+      toolchains::MSVCToolChain::SubDirectoryType::Bin));
+  return llvm::sys::fs::can_execute(FilePath) ? FilePath.str() : Exe;
 }
 
 void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
                                         const InputInfo &Output,
                                         const InputInfoList &Inputs,
                                         const ArgList &Args,
                                         const char *LinkingOutput) const {
   ArgStringList CmdArgs;
-  const ToolChain &TC = getToolChain();
+
+  auto &TC = static_cast<const toolchains::MSVCToolChain &>(getToolChain());
 
   assert((Output.isFilename() || Output.isNothing()) && "invalid output");
   if (Output.isFilename())
     CmdArgs.push_back(
         Args.MakeArgString(std::string("-out:") + Output.getFilename()));
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles) &&
       !C.getDriver().IsCLMode())
     CmdArgs.push_back("-defaultlib:libcmt");
 
   if (!llvm::sys::Process::GetEnv("LIB")) {
     // If the VC environment hasn't been configured (perhaps because the user
     // did not run vcvarsall), try to build a consistent link environment.  If
     // the environment variable is set however, assume the user knows what
     // they're doing.
-    std::string VisualStudioDir;
-    const auto &MSVC = static_cast<const toolchains::MSVCToolChain &>(TC);
-    if (MSVC.getVisualStudioInstallDir(VisualStudioDir)) {
-      SmallString<128> LibDir(VisualStudioDir);
-      llvm::sys::path::append(LibDir, "VC", "lib");
-      switch (MSVC.getArch()) {
-      case llvm::Triple::x86:
-        // x86 just puts the libraries directly in lib
-        break;
-      case llvm::Triple::x86_64:
-        llvm::sys::path::append(LibDir, "amd64");
-        break;
-      case llvm::Triple::arm:
-        llvm::sys::path::append(LibDir, "arm");
-        break;
-      default:
-        break;
-      }
-      CmdArgs.push_back(
-          Args.MakeArgString(std::string("-libpath:") + LibDir.c_str()));
+    CmdArgs.push_back(Args.MakeArgString(
+        Twine("-libpath:") +
+        TC.getSubDirectoryPath(
+            toolchains::MSVCToolChain::SubDirectoryType::Lib)));
 
-      if (MSVC.useUniversalCRT(VisualStudioDir)) {
-        std::string UniversalCRTLibPath;
-        if (MSVC.getUniversalCRTLibraryPath(UniversalCRTLibPath))
-          CmdArgs.push_back(Args.MakeArgString(std::string("-libpath:") +
-                                               UniversalCRTLibPath));
-      }
+    if (TC.useUniversalCRT()) {
+      if (TC.getUniversalCRTLibraryPath(UniversalCRTLibPath))
+        CmdArgs.push_back(
+            Args.MakeArgString(Twine("-libpath:") + UniversalCRTLibPath));
     }
 
     std::string WindowsSdkLibPath;
-    if (MSVC.getWindowsSDKLibraryPath(WindowsSdkLibPath))
+    if (TC.getWindowsSDKLibraryPath(WindowsSdkLibPath))
       CmdArgs.push_back(
           Args.MakeArgString(std::string("-libpath:") + WindowsSdkLibPath));
   }
 
   if (!C.getDriver().IsCLMode() && Args.hasArg(options::OPT_L))
     for (const auto &LibPath : Args.getAllArgValues(options::OPT_L))
       CmdArgs.push_back(Args.MakeArgString("-libpath:" + LibPath));
 
void visualstudio::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   StringRef Linker = Args.getLastArgValue(options::OPT_fuse_ld_EQ, "link");
   if (Linker.equals_lower("lld"))
     Linker = "lld-link";
 
   if (Linker.equals_lower("link")) {
     // If we're using the MSVC linker, it's not sufficient to just use link
     // from the program PATH, because other environments like GnuWin32 install
     // their own link.exe which may come first.
-    linkPath = FindVisualStudioExecutable(TC, "link.exe",
-                                          C.getDriver().getClangProgramPath());
+    linkPath = FindVisualStudioExecutable(TC, "link.exe");
   } else {
     linkPath = Linker;
     llvm::sys::path::replace_extension(linkPath, "exe");
     linkPath = TC.GetProgramPath(linkPath.c_str());
   }
 
   const char *Exec = Args.MakeArgString(linkPath);
   C.addCommand(llvm::make_unique<Command>(JA, *this, Exec, CmdArgs, Inputs));
else
     II.getInputArg().renderAsInput(Args, CmdArgs);
 
   // Output filename.
   assert(Output.getType() == types::TY_Object);
   const char *Fo =
       Args.MakeArgString(std::string("/Fo") + Output.getFilename());
   CmdArgs.push_back(Fo);
 
-  const Driver &D = getToolChain().getDriver();
-  std::string Exec = FindVisualStudioExecutable(getToolChain(), "cl.exe",
-                                                D.getClangProgramPath());
+  std::string Exec = FindVisualStudioExecutable(getToolChain(), "cl.exe");
   return llvm::make_unique<Command>(JA, *this, Args.MakeArgString(Exec),
                                     CmdArgs, Inputs);
 }
 
 MSVCToolChain::MSVCToolChain(const Driver &D, const llvm::Triple &Triple,
                              const ArgList &Args)
     : ToolChain(D, Triple, Args), CudaInstallation(D, Triple, Args) {
   getProgramPaths().push_back(getDriver().getInstalledDir());
   if (getDriver().getInstalledDir() != getDriver().Dir)
     getProgramPaths().push_back(getDriver().Dir);
+
+  // Check the environment first, since that's probably the user telling us
+  // what they want to use.
+  // Failing that, just try to find the newest Visual Studio version we can
+  // and use its default VC toolchain.
+  findVCToolChainViaEnvironment(VCToolChainPath, IsVS2017OrNewer) ||
+      findVCToolChainViaSetupConfig(VCToolChainPath, IsVS2017OrNewer) ||
+      findVCToolChainViaRegistry(VCToolChainPath, IsVS2017OrNewer);
 }
 
 Tool *MSVCToolChain::buildLinker() const {
+  if (VCToolChainPath.empty())
+    getDriver().Diag(clang::diag::warn_drv_msvc_not_found);
   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;
void MSVCToolChain::AddCudaIncludeArgs(const ArgList &DriverArgs,
                                        ArgStringList &CC1Args) const {
   CudaInstallation.AddCudaIncludeArgs(DriverArgs, CC1Args);
 }
 
 void MSVCToolChain::printVerboseInfo(raw_ostream &OS) const {
   CudaInstallation.print(OS);
 }
 
+// Windows SDKs and VC Toolchains group their contents into subdirectories based
+// on the target architecture. This function converts an llvm::Triple::ArchType
+// to the corresponding subdirectory name.
+static const char *llvmArchToWindowsSDKArch(llvm::Triple::ArchType Arch) {
+  using ArchType = llvm::Triple::ArchType;
+  switch (Arch) {
+  case ArchType::x86:
+    return "x86";
+  case ArchType::x86_64:
+    return "x64";
+  case ArchType::arm:
+    return "arm";
+  default:
+    return "";
+  }
+}
+
+// Similar to the above function, but for Visual Studios before VS2017.
+static const char *llvmArchToLegacyVCArch(llvm::Triple::ArchType Arch) {
+  using ArchType = llvm::Triple::ArchType;
+  switch (Arch) {
+  case ArchType::x86:
+    // x86 is default in legacy VC toolchains.
+    // e.g. x86 libs are directly in /lib as opposed to /lib/x86.
+    return "";
+  case ArchType::x86_64:
+    return "amd64";
+  case ArchType::arm:
+    return "arm";
+  default:
+    return "";
+  }
+}
+
+// Get the path to a specific subdirectory in the current toolchain for
+// a given target architecture.
+// VS2017 changed the VC toolchain layout, so this should be used instead
+// of hardcoding paths.
+std::string
+MSVCToolChain::getSubDirectoryPath(SubDirectoryType Type,
+                                   llvm::Triple::ArchType TargetArch) const {
+  llvm::SmallString<256> Path(VCToolChainPath);
+  switch (Type) {
+  case SubDirectoryType::Bin:
+    if (IsVS2017OrNewer) {
+      bool HostIsX64 =
+          llvm::Triple(llvm::sys::getProcessTriple()).isArch64Bit();
+      llvm::sys::path::append(Path, "bin", (HostIsX64 ? "HostX64" : "HostX86"),
+                              llvmArchToWindowsSDKArch(TargetArch));
+
+    } else {
+      llvm::sys::path::append(Path, "bin", llvmArchToLegacyVCArch(TargetArch));
+    }
+    break;
+  case SubDirectoryType::Include:
+    llvm::sys::path::append(Path, "include");
+    break;
+  case SubDirectoryType::Lib:
+    llvm::sys::path::append(
+        Path, "lib", IsVS2017OrNewer ? llvmArchToWindowsSDKArch(TargetArch)
+                                     : llvmArchToLegacyVCArch(TargetArch));
+    break;
+  }
+  return Path.str();
+}
+
 #ifdef USE_WIN32
 static bool readFullStringValue(HKEY hkey, const char *valueName,
                                 std::string &value) {
   std::wstring WideValueName;
   if (!llvm::ConvertUTF8toWide(valueName, WideValueName))
     return false;
 
   DWORD result = 0;
if (lResult == ERROR_SUCCESS) {
         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,
+static bool getWindows10SDKVersionFromPath(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 {
+static bool getWindowsSDKDir(std::string &Path, int &Major,
+                             std::string &WindowsSDKLibVersion) {
   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;
for (const char *Test : Tests) {
       if (llvm::sys::fs::exists(TestPath.c_str())) {
         WindowsSDKLibVersion = Test;
         break;
       }
     }
     return !WindowsSDKLibVersion.empty();
   }
   if (Major == 10) {
-    if (!getWindows10SDKVersion(Path, WindowsSDKIncludeVersion))
+    if (!getWindows10SDKVersionFromPath(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) {
+  if (sdkMajor >= 8) {
+    llvm::sys::path::append(libPath, windowsSDKLibVersion, "um",
+                            llvmArchToWindowsSDKArch(getArch()));
+  } else {
     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");
-
+bool MSVCToolChain::useUniversalCRT() const {
+  llvm::SmallString<128> TestPath(
+      getSubDirectoryPath(SubDirectoryType::Include));
+  llvm::sys::path::append(TestPath, "stdlib.h");
   return !llvm::sys::fs::exists(TestPath);
 }
 
-bool MSVCToolChain::getUniversalCRTSdkDir(std::string &Path,
-                                          std::string &UCRTVersion) const {
+static bool getUniversalCRTSdkDir(std::string &Path, std::string &UCRTVersion) {
   // 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);
+  return getWindows10SDKVersionFromPath(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());
+  StringRef ArchName = llvmArchToWindowsSDKArch(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");
-        // Checking if cl.exe exists is a small optimization over calling
-        // can_execute, which really only checks for existence but will also do
-        // extra checks for cl.exe.exe.  These add up when walking a long path.
-        if (llvm::sys::fs::exists(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;
-}
-
-VersionTuple MSVCToolChain::getMSVCVersionFromTriple() const {
+static VersionTuple getMSVCVersionFromTriple(const llvm::Triple &Triple) {
   unsigned Major, Minor, Micro;
-  getTriple().getEnvironmentVersion(Major, Minor, Micro);
+  Triple.getEnvironmentVersion(Major, Minor, Micro);
   if (Major || Minor || Micro)
     return VersionTuple(Major, Minor, Micro);
   return VersionTuple();
 }
 
-VersionTuple MSVCToolChain::getMSVCVersionFromExe() const {
+static VersionTuple getMSVCVersionFromExe(const std::string &BinDir) {
   VersionTuple Version;
 #ifdef USE_WIN32
-  std::string BinPath;
-  if (!getVisualStudioBinariesFolder("", BinPath))
-    return Version;
-  SmallString<128> ClExe(BinPath);
+  SmallString<128> ClExe(BinDir);
   llvm::sys::path::append(ClExe, "cl.exe");
 
   std::wstring ClExeWide;
   if (!llvm::ConvertUTF8toWide(ClExe.c_str(), ClExeWide))
     return Version;
 
   const DWORD VersionSize = ::GetFileVersionInfoSizeW(ClExeWide.c_str(),
                                                       nullptr);
#ifdef USE_WIN32
   const unsigned Minor = (FileInfo->dwFileVersionMS      ) & 0xFFFF;
   const unsigned Micro = (FileInfo->dwFileVersionLS >> 16) & 0xFFFF;
 
   Version = VersionTuple(Major, Minor, Micro);
 #endif
   return Version;
 }
 
-// Get Visual Studio installation directory.
-bool MSVCToolChain::getVisualStudioInstallDir(std::string &path) const {
-  // First check the environment variables that vsvars32.bat sets.
-  if (llvm::Optional<std::string> VcInstallDir =
-          llvm::sys::Process::GetEnv("VCINSTALLDIR")) {
-    path = std::move(*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.
-  std::string vcomntools;
-  if (llvm::Optional<std::string> vs120comntools =
-          llvm::sys::Process::GetEnv("VS120COMNTOOLS"))
-    vcomntools = std::move(*vs120comntools);
-  else if (llvm::Optional<std::string> vs100comntools =
-               llvm::sys::Process::GetEnv("VS100COMNTOOLS"))
-    vcomntools = std::move(*vs100comntools);
-  else if (llvm::Optional<std::string> vs90comntools =
-               llvm::sys::Process::GetEnv("VS90COMNTOOLS"))
-    vcomntools = std::move(*vs90comntools);
-  else if (llvm::Optional<std::string> vs80comntools =
-               llvm::sys::Process::GetEnv("VS80COMNTOOLS"))
-    vcomntools = std::move(*vs80comntools);
-
-  // Find any version we can.
-  if (!vcomntools.empty()) {
-    size_t p = vcomntools.find("\\Common7\\Tools");
-    if (p != std::string::npos)
-      vcomntools.resize(p);
-    path = std::move(vcomntools);
-    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);
 }
if (llvm::Optional<std::string> cl_include_dir =
     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 (!VCToolChainPath.empty()) {
+    addSystemInclude(DriverArgs, CC1Args,
+                     getSubDirectoryPath(SubDirectoryType::Include));
 
-    if (useUniversalCRT(VSDir)) {
+    if (useUniversalCRT()) {
       std::string UniversalCRTSdkPath;
       std::string UCRTVersion;
       if (getUniversalCRTSdkDir(UniversalCRTSdkPath, UCRTVersion)) {
         AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, UniversalCRTSdkPath,
                                       "Include", UCRTVersion, "ucrt");
       }
     }
 
if (getWindowsSDKDir(WindowsSDKDir, major, windowsSDKIncludeVersion,
                                       "um");
         AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
                                       "include", windowsSDKIncludeVersion,
                                       "winrt");
       } else {
         AddSystemIncludeWithSubfolder(DriverArgs, CC1Args, WindowsSDKDir,
                                       "include");
       }
-    } else {
-      addSystemInclude(DriverArgs, CC1Args, VSDir);
     }
+
     return;
   }
 
 #if defined(LLVM_ON_WIN32)
   // 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",
void MSVCToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                                  ArgStringList &CC1Args) const {
   // FIXME: There should probably be logic here to find libc++ on Windows.
 }
 
 VersionTuple MSVCToolChain::computeMSVCVersion(const Driver *D,
                                                const ArgList &Args) const {
   bool IsWindowsMSVC = getTriple().isWindowsMSVCEnvironment();
   VersionTuple MSVT = ToolChain::computeMSVCVersion(D, Args);
-  if (MSVT.empty()) MSVT = getMSVCVersionFromTriple();
-  if (MSVT.empty() && IsWindowsMSVC) MSVT = getMSVCVersionFromExe();
+  if (MSVT.empty())
+    MSVT = getMSVCVersionFromTriple(getTriple());
+  if (MSVT.empty() && IsWindowsMSVC)
+    MSVT = getMSVCVersionFromExe(getSubDirectoryPath(SubDirectoryType::Bin));
   if (MSVT.empty() &&
       Args.hasFlag(options::OPT_fms_extensions, options::OPT_fno_ms_extensions,
                    IsWindowsMSVC)) {
     // -fms-compatibility-version=18.00 is default.
     // FIXME: Consider bumping this to 19 (MSVC2015) soon.
     MSVT = VersionTuple(18);
   }
   return MSVT;

clang/lib/Driver/ToolChains/MSVCSetupApi.h

+// <copyright file="Program.cpp" company="Microsoft Corporation">
+// Copyright (C) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT license. See LICENSE.txt in the project root for
+// license information.
+// </copyright>
+
+#pragma once
+
+// Constants
+//
+#ifndef E_NOTFOUND
+#define E_NOTFOUND HRESULT_FROM_WIN32(ERROR_NOT_FOUND)
+#endif
+
+#ifndef E_FILENOTFOUND
+#define E_FILENOTFOUND HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND)
+#endif
+
+// Enumerations
+//
+/// <summary>
+/// The state of an instance.
+/// </summary>
+enum InstanceState : unsigned {
+  /// <summary>
+  /// The instance state has not been determined.
+  /// </summary>
+  eNone = 0,
+
+  /// <summary>
+  /// The instance installation path exists.
+  /// </summary>
+  eLocal = 1,
+
+  /// <summary>
+  /// A product is registered to the instance.
+  /// </summary>
+  eRegistered = 2,
+
+  /// <summary>
+  /// No reboot is required for the instance.
+  /// </summary>
+  eNoRebootRequired = 4,
+
+  /// <summary>
+  /// The instance represents a complete install.
+  /// </summary>
+  eComplete = MAXUINT,
+};
+
+// Forward interface declarations
+//
+#ifndef __ISetupInstance_FWD_DEFINED__
+#define __ISetupInstance_FWD_DEFINED__
+typedef struct ISetupInstance ISetupInstance;
+#endif
+
+#ifndef __ISetupInstance2_FWD_DEFINED__
+#define __ISetupInstance2_FWD_DEFINED__
+typedef struct ISetupInstance2 ISetupInstance2;
+#endif
+
+#ifndef __IEnumSetupInstances_FWD_DEFINED__
+#define __IEnumSetupInstances_FWD_DEFINED__
+typedef struct IEnumSetupInstances IEnumSetupInstances;
+#endif
+
+#ifndef __ISetupConfiguration_FWD_DEFINED__
+#define __ISetupConfiguration_FWD_DEFINED__
+typedef struct ISetupConfiguration ISetupConfiguration;
+#endif
+
+#ifndef __ISetupConfiguration2_FWD_DEFINED__
+#define __ISetupConfiguration2_FWD_DEFINED__
+typedef struct ISetupConfiguration2 ISetupConfiguration2;
+#endif
+
+#ifndef __ISetupPackageReference_FWD_DEFINED__
+#define __ISetupPackageReference_FWD_DEFINED__
+typedef struct ISetupPackageReference ISetupPackageReference;
+#endif
+
+#ifndef __ISetupHelper_FWD_DEFINED__
+#define __ISetupHelper_FWD_DEFINED__
+typedef struct ISetupHelper ISetupHelper;
+#endif
+
+// Forward class declarations
+//
+#ifndef __SetupConfiguration_FWD_DEFINED__
+#define __SetupConfiguration_FWD_DEFINED__
+
+#ifdef __cplusplus
+typedef class SetupConfiguration SetupConfiguration;
+#endif
+
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// Interface definitions
+//
+EXTERN_C const IID IID_ISetupInstance;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// Information about an instance of a product.
+/// </summary>
+struct DECLSPEC_UUID("B41463C3-8866-43B5-BC33-2B0676F7F42E")
+    DECLSPEC_NOVTABLE ISetupInstance : public IUnknown {
+  /// <summary>
+  /// Gets the instance identifier (should match the name of the parent instance
+  /// directory).
+  /// </summary>
+  /// <param name="pbstrInstanceId">The instance identifier.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist.</returns>
+  STDMETHOD(GetInstanceId)(_Out_ BSTR *pbstrInstanceId) = 0;
+
+  /// <summary>
+  /// Gets the local date and time when the installation was originally
+  /// installed.
+  /// </summary>
+  /// <param name="pInstallDate">The local date and time when the installation
+  /// was originally installed.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetInstallDate)(_Out_ LPFILETIME pInstallDate) = 0;
+
+  /// <summary>
+  /// Gets the unique name of the installation, often indicating the branch and
+  /// other information used for telemetry.
+  /// </summary>
+  /// <param name="pbstrInstallationName">The unique name of the installation,
+  /// often indicating the branch and other information used for
+  /// telemetry.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetInstallationName)(_Out_ BSTR *pbstrInstallationName) = 0;
+
+  /// <summary>
+  /// Gets the path to the installation root of the product.
+  /// </summary>
+  /// <param name="pbstrInstallationPath">The path to the installation root of
+  /// the product.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetInstallationPath)(_Out_ BSTR *pbstrInstallationPath) = 0;
+
+  /// <summary>
+  /// Gets the version of the product installed in this instance.
+  /// </summary>
+  /// <param name="pbstrInstallationVersion">The version of the product
+  /// installed in this instance.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetInstallationVersion)(_Out_ BSTR *pbstrInstallationVersion) = 0;
+
+  /// <summary>
+  /// Gets the display name (title) of the product installed in this instance.
+  /// </summary>
+  /// <param name="lcid">The LCID for the display name.</param>
+  /// <param name="pbstrDisplayName">The display name (title) of the product
+  /// installed in this instance.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetDisplayName)(_In_ LCID lcid, _Out_ BSTR *pbstrDisplayName) = 0;
+
+  /// <summary>
+  /// Gets the description of the product installed in this instance.
+  /// </summary>
+  /// <param name="lcid">The LCID for the description.</param>
+  /// <param name="pbstrDescription">The description of the product installed in
+  /// this instance.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(GetDescription)(_In_ LCID lcid, _Out_ BSTR *pbstrDescription) = 0;
+
+  /// <summary>
+  /// Resolves the optional relative path to the root path of the instance.
+  /// </summary>
+  /// <param name="pwszRelativePath">A relative path within the instance to
+  /// resolve, or NULL to get the root path.</param>
+  /// <param name="pbstrAbsolutePath">The full path to the optional relative
+  /// path within the instance. If the relative path is NULL, the root path will
+  /// always terminate in a backslash.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// property is not defined.</returns>
+  STDMETHOD(ResolvePath)
+  (_In_opt_z_ LPCOLESTR pwszRelativePath, _Out_ BSTR *pbstrAbsolutePath) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_ISetupInstance2;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// Information about an instance of a product.
+/// </summary>
+struct DECLSPEC_UUID("89143C9A-05AF-49B0-B717-72E218A2185C")
+    DECLSPEC_NOVTABLE ISetupInstance2 : public ISetupInstance {
+  /// <summary>
+  /// Gets the state of the instance.
+  /// </summary>
+  /// <param name="pState">The state of the instance.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist.</returns>
+  STDMETHOD(GetState)(_Out_ InstanceState *pState) = 0;
+
+  /// <summary>
+  /// Gets an array of package references registered to the instance.
+  /// </summary>
+  /// <param name="ppsaPackages">Pointer to an array of <see
+  /// cref="ISetupPackageReference"/>.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// packages property is not defined.</returns>
+  STDMETHOD(GetPackages)(_Out_ LPSAFEARRAY *ppsaPackages) = 0;
+
+  /// <summary>
+  /// Gets a pointer to the <see cref="ISetupPackageReference"/> that represents
+  /// the registered product.
+  /// </summary>
+  /// <param name="ppPackage">Pointer to an instance of <see
+  /// cref="ISetupPackageReference"/>. This may be NULL if <see
+  /// cref="GetState"/> does not return <see cref="eComplete"/>.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist and E_NOTFOUND if the
+  /// packages property is not defined.</returns>
+  STDMETHOD(GetProduct)
+  (_Outptr_result_maybenull_ ISetupPackageReference **ppPackage) = 0;
+
+  /// <summary>
+  /// Gets the relative path to the product application, if available.
+  /// </summary>
+  /// <param name="pbstrProductPath">The relative path to the product
+  /// application, if available.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_FILENOTFOUND if the instance state does not exist.</returns>
+  STDMETHOD(GetProductPath)
+  (_Outptr_result_maybenull_ BSTR *pbstrProductPath) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_IEnumSetupInstances;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// A enumerator of installed <see cref="ISetupInstance"/> objects.
+/// </summary>
+struct DECLSPEC_UUID("6380BCFF-41D3-4B2E-8B2E-BF8A6810C848")
+    DECLSPEC_NOVTABLE IEnumSetupInstances : public IUnknown {
+  /// <summary>
+  /// Retrieves the next set of product instances in the enumeration sequence.
+  /// </summary>
+  /// <param name="celt">The number of product instances to retrieve.</param>
+  /// <param name="rgelt">A pointer to an array of <see
+  /// cref="ISetupInstance"/>.</param>
+  /// <param name="pceltFetched">A pointer to the number of product instances
+  /// retrieved. If celt is 1 this parameter may be NULL.</param>
+  /// <returns>S_OK if the number of elements were fetched, S_FALSE if nothing
+  /// was fetched (at end of enumeration), E_INVALIDARG if celt is greater than
+  /// 1 and pceltFetched is NULL, or E_OUTOFMEMORY if an <see
+  /// cref="ISetupInstance"/> could not be allocated.</returns>
+  STDMETHOD(Next)
+  (_In_ ULONG celt, _Out_writes_to_(celt, *pceltFetched) ISetupInstance **rgelt,
+   _Out_opt_ _Deref_out_range_(0, celt) ULONG *pceltFetched) = 0;
+
+  /// <summary>
+  /// Skips the next set of product instances in the enumeration sequence.
+  /// </summary>
+  /// <param name="celt">The number of product instances to skip.</param>
+  /// <returns>S_OK if the number of elements could be skipped; otherwise,
+  /// S_FALSE;</returns>
+  STDMETHOD(Skip)(_In_ ULONG celt) = 0;
+
+  /// <summary>
+  /// Resets the enumeration sequence to the beginning.
+  /// </summary>
+  /// <returns>Always returns S_OK;</returns>
+  STDMETHOD(Reset)(void) = 0;
+
+  /// <summary>
+  /// Creates a new enumeration object in the same state as the current
+  /// enumeration object: the new object points to the same place in the
+  /// enumeration sequence.
+  /// </summary>
+  /// <param name="ppenum">A pointer to a pointer to a new <see
+  /// cref="IEnumSetupInstances"/> interface. If the method fails, this
+  /// parameter is undefined.</param>
+  /// <returns>S_OK if a clone was returned; otherwise, E_OUTOFMEMORY.</returns>
+  STDMETHOD(Clone)(_Deref_out_opt_ IEnumSetupInstances **ppenum) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_ISetupConfiguration;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// Gets information about product instances set up on the machine.
+/// </summary>
+struct DECLSPEC_UUID("42843719-DB4C-46C2-8E7C-64F1816EFD5B")
+    DECLSPEC_NOVTABLE ISetupConfiguration : public IUnknown {
+  /// <summary>
+  /// Enumerates all completed product instances installed.
+  /// </summary>
+  /// <param name="ppEnumInstances">An enumeration of completed, installed
+  /// product instances.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(EnumInstances)(_Out_ IEnumSetupInstances **ppEnumInstances) = 0;
+
+  /// <summary>
+  /// Gets the instance for the current process path.
+  /// </summary>
+  /// <param name="ppInstance">The instance for the current process
+  /// path.</param>
+  /// <returns>The instance for the current process path, or E_NOTFOUND if not
+  /// found.</returns>
+  STDMETHOD(GetInstanceForCurrentProcess)
+  (_Out_ ISetupInstance **ppInstance) = 0;
+
+  /// <summary>
+  /// Gets the instance for the given path.
+  /// </summary>
+  /// <param name="ppInstance">The instance for the given path.</param>
+  /// <returns>The instance for the given path, or E_NOTFOUND if not
+  /// found.</returns>
+  STDMETHOD(GetInstanceForPath)
+  (_In_z_ LPCWSTR wzPath, _Out_ ISetupInstance **ppInstance) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_ISetupConfiguration2;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// Gets information about product instances.
+/// </summary>
+struct DECLSPEC_UUID("26AAB78C-4A60-49D6-AF3B-3C35BC93365D")
+    DECLSPEC_NOVTABLE ISetupConfiguration2 : public ISetupConfiguration {
+  /// <summary>
+  /// Enumerates all product instances.
+  /// </summary>
+  /// <param name="ppEnumInstances">An enumeration of all product
+  /// instances.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(EnumAllInstances)(_Out_ IEnumSetupInstances **ppEnumInstances) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_ISetupPackageReference;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// A reference to a package.
+/// </summary>
+struct DECLSPEC_UUID("da8d8a16-b2b6-4487-a2f1-594ccccd6bf5")
+    DECLSPEC_NOVTABLE ISetupPackageReference : public IUnknown {
+  /// <summary>
+  /// Gets the general package identifier.
+  /// </summary>
+  /// <param name="pbstrId">The general package identifier.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetId)(_Out_ BSTR *pbstrId) = 0;
+
+  /// <summary>
+  /// Gets the version of the package.
+  /// </summary>
+  /// <param name="pbstrVersion">The version of the package.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetVersion)(_Out_ BSTR *pbstrVersion) = 0;
+
+  /// <summary>
+  /// Gets the target process architecture of the package.
+  /// </summary>
+  /// <param name="pbstrChip">The target process architecture of the
+  /// package.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetChip)(_Out_ BSTR *pbstrChip) = 0;
+
+  /// <summary>
+  /// Gets the language and optional region identifier.
+  /// </summary>
+  /// <param name="pbstrLanguage">The language and optional region
+  /// identifier.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetLanguage)(_Out_ BSTR *pbstrLanguage) = 0;
+
+  /// <summary>
+  /// Gets the build branch of the package.
+  /// </summary>
+  /// <param name="pbstrBranch">The build branch of the package.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetBranch)(_Out_ BSTR *pbstrBranch) = 0;
+
+  /// <summary>
+  /// Gets the type of the package.
+  /// </summary>
+  /// <param name="pbstrType">The type of the package.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(GetType)(_Out_ BSTR *pbstrType) = 0;
+
+  /// <summary>
+  /// Gets the unique identifier consisting of all defined tokens.
+  /// </summary>
+  /// <param name="pbstrUniqueId">The unique identifier consisting of all
+  /// defined tokens.</param>
+  /// <returns>Standard HRESULT indicating success or failure, including
+  /// E_UNEXPECTED if no Id was defined (required).</returns>
+  STDMETHOD(GetUniqueId)(_Out_ BSTR *pbstrUniqueId) = 0;
+};
+#endif
+
+EXTERN_C const IID IID_ISetupHelper;
+
+#if defined(__cplusplus) && !defined(CINTERFACE)
+/// <summary>
+/// Helper functions.
+/// </summary>
+/// <remarks>
+/// You can query for this interface from the <see cref="SetupConfiguration"/>
+/// class.
+/// </remarks>
+struct DECLSPEC_UUID("42b21b78-6192-463e-87bf-d577838f1d5c")
+    DECLSPEC_NOVTABLE ISetupHelper : public IUnknown {
+  /// <summary>
+  /// Parses a dotted quad version string into a 64-bit unsigned integer.
+  /// </summary>
+  /// <param name="pwszVersion">The dotted quad version string to parse, e.g.
+  /// 1.2.3.4.</param>
+  /// <param name="pullVersion">A 64-bit unsigned integer representing the
+  /// version. You can compare this to other versions.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(ParseVersion)
+  (_In_ LPCOLESTR pwszVersion, _Out_ PULONGLONG pullVersion) = 0;
+
+  /// <summary>
+  /// Parses a dotted quad version string into a 64-bit unsigned integer.
+  /// </summary>
+  /// <param name="pwszVersionRange">The string containing 1 or 2 dotted quad
+  /// version strings to parse, e.g. [1.0,) that means 1.0.0.0 or newer.</param>
+  /// <param name="pullMinVersion">A 64-bit unsigned integer representing the
+  /// minimum version, which may be 0. You can compare this to other
+  /// versions.</param>
+  /// <param name="pullMaxVersion">A 64-bit unsigned integer representing the
+  /// maximum version, which may be MAXULONGLONG. You can compare this to other
+  /// versions.</param>
+  /// <returns>Standard HRESULT indicating success or failure.</returns>
+  STDMETHOD(ParseVersionRange)
+  (_In_ LPCOLESTR pwszVersionRange, _Out_ PULONGLONG pullMinVersion,
+   _Out_ PULONGLONG pullMaxVersion) = 0;
+};
+#endif
+
+// Class declarations
+//
+EXTERN_C const CLSID CLSID_SetupConfiguration;
+
+#ifdef __cplusplus
+/// <summary>
+/// This class implements <see cref="ISetupConfiguration"/>, <see
+/// cref="ISetupConfiguration2"/>, and <see cref="ISetupHelper"/>.
+/// </summary>
+class DECLSPEC_UUID("177F0C4A-1CD3-4DE7-A32C-71DBBB9FA36D") SetupConfiguration;
+#endif
+
+// Function declarations
+//
+/// <summary>
+/// Gets an <see cref="ISetupConfiguration"/> that provides information about
+/// product instances installed on the machine.
+/// </summary>
+/// <param name="ppConfiguration">The <see cref="ISetupConfiguration"/> that
+/// provides information about product instances installed on the
+/// machine.</param>
+/// <param name="pReserved">Reserved for future use.</param>
+/// <returns>Standard HRESULT indicating success or failure.</returns>
+STDMETHODIMP GetSetupConfiguration(_Out_ ISetupConfiguration **ppConfiguration,
+                                   _Reserved_ LPVOID pReserved);
+
+#ifdef __cplusplus
+}
+#endif

clang/test/Driver/cl-link-at-file.c

 // PR17239 - The /link option, when inside a response file, should only extend
 // until the end of the response file (and not the entire command line)
 
 // Note: %s must be preceded by -- or bound to another option, otherwise it may
 // be interpreted as a command-line option, e.g. on Mac where %s is commonly
 // under /Users.
 
 // RUN: echo /link bar.lib baz.lib > %t.args
 // RUN: touch %t.obj
 // RUN: %clang_cl -### @%t.args -- %t.obj 2>&1 | FileCheck %s -check-prefix=ARGS
 // If the "/link" option captures all remaining args beyond its response file,
 // it will also capture "--" and our input argument. In this case, Clang will
 // be clueless and will emit "argument unused" warnings. If PR17239 is properly
 // fixed, this should not happen because the "/link" option is restricted to
 // consume only remaining args in its response file.
-// ARGS-NOT: warning
 // ARGS-NOT: argument unused during compilation
 // Identify the linker command
 // ARGS: link.exe