xref: /freebsd/contrib/llvm-project/llvm/lib/WindowsDriver/MSVCPaths.cpp (revision 5036d9652a5701d00e9e40ea942c278e9f77d33d)
1 //===-- MSVCPaths.cpp - MSVC path-parsing helpers -------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/WindowsDriver/MSVCPaths.h"
10 #include "llvm/ADT/SmallString.h"
11 #include "llvm/ADT/SmallVector.h"
12 #include "llvm/ADT/StringExtras.h"
13 #include "llvm/ADT/StringRef.h"
14 #include "llvm/ADT/Twine.h"
15 #include "llvm/Support/Path.h"
16 #include "llvm/Support/Process.h"
17 #include "llvm/Support/Program.h"
18 #include "llvm/Support/VersionTuple.h"
19 #include "llvm/Support/VirtualFileSystem.h"
20 #include "llvm/TargetParser/Host.h"
21 #include "llvm/TargetParser/Triple.h"
22 #include <optional>
23 #include <string>
24 
25 #ifdef _WIN32
26 #include "llvm/Support/ConvertUTF.h"
27 #endif
28 
29 #ifdef _WIN32
30 #define WIN32_LEAN_AND_MEAN
31 #define NOGDI
32 #ifndef NOMINMAX
33 #define NOMINMAX
34 #endif
35 #include <windows.h>
36 #endif
37 
38 #ifdef _MSC_VER
39 // Don't support SetupApi on MinGW.
40 #define USE_MSVC_SETUP_API
41 
42 // Make sure this comes before MSVCSetupApi.h
43 #include <comdef.h>
44 
45 #include "llvm/Support/COM.h"
46 #ifdef __clang__
47 #pragma clang diagnostic push
48 #pragma clang diagnostic ignored "-Wnon-virtual-dtor"
49 #endif
50 #include "llvm/WindowsDriver/MSVCSetupApi.h"
51 #ifdef __clang__
52 #pragma clang diagnostic pop
53 #endif
54 _COM_SMARTPTR_TYPEDEF(ISetupConfiguration, __uuidof(ISetupConfiguration));
55 _COM_SMARTPTR_TYPEDEF(ISetupConfiguration2, __uuidof(ISetupConfiguration2));
56 _COM_SMARTPTR_TYPEDEF(ISetupHelper, __uuidof(ISetupHelper));
57 _COM_SMARTPTR_TYPEDEF(IEnumSetupInstances, __uuidof(IEnumSetupInstances));
58 _COM_SMARTPTR_TYPEDEF(ISetupInstance, __uuidof(ISetupInstance));
59 _COM_SMARTPTR_TYPEDEF(ISetupInstance2, __uuidof(ISetupInstance2));
60 #endif
61 
62 static std::string
63 getHighestNumericTupleInDirectory(llvm::vfs::FileSystem &VFS,
64                                   llvm::StringRef Directory) {
65   std::string Highest;
66   llvm::VersionTuple HighestTuple;
67 
68   std::error_code EC;
69   for (llvm::vfs::directory_iterator DirIt = VFS.dir_begin(Directory, EC),
70                                      DirEnd;
71        !EC && DirIt != DirEnd; DirIt.increment(EC)) {
72     auto Status = VFS.status(DirIt->path());
73     if (!Status || !Status->isDirectory())
74       continue;
75     llvm::StringRef CandidateName = llvm::sys::path::filename(DirIt->path());
76     llvm::VersionTuple Tuple;
77     if (Tuple.tryParse(CandidateName)) // tryParse() returns true on error.
78       continue;
79     if (Tuple > HighestTuple) {
80       HighestTuple = Tuple;
81       Highest = CandidateName.str();
82     }
83   }
84 
85   return Highest;
86 }
87 
88 static bool getWindows10SDKVersionFromPath(llvm::vfs::FileSystem &VFS,
89                                            const std::string &SDKPath,
90                                            std::string &SDKVersion) {
91   llvm::SmallString<128> IncludePath(SDKPath);
92   llvm::sys::path::append(IncludePath, "Include");
93   SDKVersion = getHighestNumericTupleInDirectory(VFS, IncludePath);
94   return !SDKVersion.empty();
95 }
96 
97 static bool getWindowsSDKDirViaCommandLine(
98     llvm::vfs::FileSystem &VFS, std::optional<llvm::StringRef> WinSdkDir,
99     std::optional<llvm::StringRef> WinSdkVersion,
100     std::optional<llvm::StringRef> WinSysRoot, std::string &Path, int &Major,
101     std::string &Version) {
102   if (WinSdkDir || WinSysRoot) {
103     // Don't validate the input; trust the value supplied by the user.
104     // The motivation is to prevent unnecessary file and registry access.
105     llvm::VersionTuple SDKVersion;
106     if (WinSdkVersion)
107       SDKVersion.tryParse(*WinSdkVersion);
108 
109     if (WinSysRoot) {
110       llvm::SmallString<128> SDKPath(*WinSysRoot);
111       llvm::sys::path::append(SDKPath, "Windows Kits");
112       if (!SDKVersion.empty())
113         llvm::sys::path::append(SDKPath, llvm::Twine(SDKVersion.getMajor()));
114       else
115         llvm::sys::path::append(
116             SDKPath, getHighestNumericTupleInDirectory(VFS, SDKPath));
117       Path = std::string(SDKPath);
118     } else {
119       Path = WinSdkDir->str();
120     }
121 
122     if (!SDKVersion.empty()) {
123       Major = SDKVersion.getMajor();
124       Version = SDKVersion.getAsString();
125     } else if (getWindows10SDKVersionFromPath(VFS, Path, Version)) {
126       Major = 10;
127     }
128     return true;
129   }
130   return false;
131 }
132 
133 #ifdef _WIN32
134 static bool readFullStringValue(HKEY hkey, const char *valueName,
135                                 std::string &value) {
136   std::wstring WideValueName;
137   if (!llvm::ConvertUTF8toWide(valueName, WideValueName))
138     return false;
139 
140   DWORD result = 0;
141   DWORD valueSize = 0;
142   DWORD type = 0;
143   // First just query for the required size.
144   result = RegQueryValueExW(hkey, WideValueName.c_str(), NULL, &type, NULL,
145                             &valueSize);
146   if (result != ERROR_SUCCESS || type != REG_SZ || !valueSize)
147     return false;
148   std::vector<BYTE> buffer(valueSize);
149   result = RegQueryValueExW(hkey, WideValueName.c_str(), NULL, NULL, &buffer[0],
150                             &valueSize);
151   if (result == ERROR_SUCCESS) {
152     std::wstring WideValue(reinterpret_cast<const wchar_t *>(buffer.data()),
153                            valueSize / sizeof(wchar_t));
154     if (valueSize && WideValue.back() == L'\0') {
155       WideValue.pop_back();
156     }
157     // The destination buffer must be empty as an invariant of the conversion
158     // function; but this function is sometimes called in a loop that passes in
159     // the same buffer, however. Simply clear it out so we can overwrite it.
160     value.clear();
161     return llvm::convertWideToUTF8(WideValue, value);
162   }
163   return false;
164 }
165 #endif
166 
167 /// Read registry string.
168 /// This also supports a means to look for high-versioned keys by use
169 /// of a $VERSION placeholder in the key path.
170 /// $VERSION in the key path is a placeholder for the version number,
171 /// causing the highest value path to be searched for and used.
172 /// I.e. "SOFTWARE\\Microsoft\\VisualStudio\\$VERSION".
173 /// There can be additional characters in the component.  Only the numeric
174 /// characters are compared.  This function only searches HKLM.
175 static bool getSystemRegistryString(const char *keyPath, const char *valueName,
176                                     std::string &value, std::string *phValue) {
177 #ifndef _WIN32
178   return false;
179 #else
180   HKEY hRootKey = HKEY_LOCAL_MACHINE;
181   HKEY hKey = NULL;
182   long lResult;
183   bool returnValue = false;
184 
185   const char *placeHolder = strstr(keyPath, "$VERSION");
186   std::string bestName;
187   // If we have a $VERSION placeholder, do the highest-version search.
188   if (placeHolder) {
189     const char *keyEnd = placeHolder - 1;
190     const char *nextKey = placeHolder;
191     // Find end of previous key.
192     while ((keyEnd > keyPath) && (*keyEnd != '\\'))
193       keyEnd--;
194     // Find end of key containing $VERSION.
195     while (*nextKey && (*nextKey != '\\'))
196       nextKey++;
197     size_t partialKeyLength = keyEnd - keyPath;
198     char partialKey[256];
199     if (partialKeyLength >= sizeof(partialKey))
200       partialKeyLength = sizeof(partialKey) - 1;
201     strncpy(partialKey, keyPath, partialKeyLength);
202     partialKey[partialKeyLength] = '\0';
203     HKEY hTopKey = NULL;
204     lResult = RegOpenKeyExA(hRootKey, partialKey, 0, KEY_READ | KEY_WOW64_32KEY,
205                             &hTopKey);
206     if (lResult == ERROR_SUCCESS) {
207       char keyName[256];
208       double bestValue = 0.0;
209       DWORD index, size = sizeof(keyName) - 1;
210       for (index = 0; RegEnumKeyExA(hTopKey, index, keyName, &size, NULL, NULL,
211                                     NULL, NULL) == ERROR_SUCCESS;
212            index++) {
213         const char *sp = keyName;
214         while (*sp && !llvm::isDigit(*sp))
215           sp++;
216         if (!*sp)
217           continue;
218         const char *ep = sp + 1;
219         while (*ep && (llvm::isDigit(*ep) || (*ep == '.')))
220           ep++;
221         char numBuf[32];
222         strncpy(numBuf, sp, sizeof(numBuf) - 1);
223         numBuf[sizeof(numBuf) - 1] = '\0';
224         double dvalue = strtod(numBuf, NULL);
225         if (dvalue > bestValue) {
226           // Test that InstallDir is indeed there before keeping this index.
227           // Open the chosen key path remainder.
228           bestName = keyName;
229           // Append rest of key.
230           bestName.append(nextKey);
231           lResult = RegOpenKeyExA(hTopKey, bestName.c_str(), 0,
232                                   KEY_READ | KEY_WOW64_32KEY, &hKey);
233           if (lResult == ERROR_SUCCESS) {
234             if (readFullStringValue(hKey, valueName, value)) {
235               bestValue = dvalue;
236               if (phValue)
237                 *phValue = bestName;
238               returnValue = true;
239             }
240             RegCloseKey(hKey);
241           }
242         }
243         size = sizeof(keyName) - 1;
244       }
245       RegCloseKey(hTopKey);
246     }
247   } else {
248     lResult =
249         RegOpenKeyExA(hRootKey, keyPath, 0, KEY_READ | KEY_WOW64_32KEY, &hKey);
250     if (lResult == ERROR_SUCCESS) {
251       if (readFullStringValue(hKey, valueName, value))
252         returnValue = true;
253       if (phValue)
254         phValue->clear();
255       RegCloseKey(hKey);
256     }
257   }
258   return returnValue;
259 #endif // _WIN32
260 }
261 
262 namespace llvm {
263 
264 const char *archToWindowsSDKArch(Triple::ArchType Arch) {
265   switch (Arch) {
266   case Triple::ArchType::x86:
267     return "x86";
268   case Triple::ArchType::x86_64:
269     return "x64";
270   case Triple::ArchType::arm:
271   case Triple::ArchType::thumb:
272     return "arm";
273   case Triple::ArchType::aarch64:
274     return "arm64";
275   default:
276     return "";
277   }
278 }
279 
280 const char *archToLegacyVCArch(Triple::ArchType Arch) {
281   switch (Arch) {
282   case Triple::ArchType::x86:
283     // x86 is default in legacy VC toolchains.
284     // e.g. x86 libs are directly in /lib as opposed to /lib/x86.
285     return "";
286   case Triple::ArchType::x86_64:
287     return "amd64";
288   case Triple::ArchType::arm:
289   case Triple::ArchType::thumb:
290     return "arm";
291   case Triple::ArchType::aarch64:
292     return "arm64";
293   default:
294     return "";
295   }
296 }
297 
298 const char *archToDevDivInternalArch(Triple::ArchType Arch) {
299   switch (Arch) {
300   case Triple::ArchType::x86:
301     return "i386";
302   case Triple::ArchType::x86_64:
303     return "amd64";
304   case Triple::ArchType::arm:
305   case Triple::ArchType::thumb:
306     return "arm";
307   case Triple::ArchType::aarch64:
308     return "arm64";
309   default:
310     return "";
311   }
312 }
313 
314 bool appendArchToWindowsSDKLibPath(int SDKMajor, SmallString<128> LibPath,
315                                    Triple::ArchType Arch, std::string &path) {
316   if (SDKMajor >= 8) {
317     sys::path::append(LibPath, archToWindowsSDKArch(Arch));
318   } else {
319     switch (Arch) {
320     // In Windows SDK 7.x, x86 libraries are directly in the Lib folder.
321     case Triple::x86:
322       break;
323     case Triple::x86_64:
324       sys::path::append(LibPath, "x64");
325       break;
326     case Triple::arm:
327     case Triple::thumb:
328       // It is not necessary to link against Windows SDK 7.x when targeting ARM.
329       return false;
330     default:
331       return false;
332     }
333   }
334 
335   path = std::string(LibPath);
336   return true;
337 }
338 
339 std::string getSubDirectoryPath(SubDirectoryType Type, ToolsetLayout VSLayout,
340                                 const std::string &VCToolChainPath,
341                                 Triple::ArchType TargetArch,
342                                 StringRef SubdirParent) {
343   const char *SubdirName;
344   const char *IncludeName;
345   switch (VSLayout) {
346   case ToolsetLayout::OlderVS:
347     SubdirName = archToLegacyVCArch(TargetArch);
348     IncludeName = "include";
349     break;
350   case ToolsetLayout::VS2017OrNewer:
351     SubdirName = archToWindowsSDKArch(TargetArch);
352     IncludeName = "include";
353     break;
354   case ToolsetLayout::DevDivInternal:
355     SubdirName = archToDevDivInternalArch(TargetArch);
356     IncludeName = "inc";
357     break;
358   }
359 
360   SmallString<256> Path(VCToolChainPath);
361   if (!SubdirParent.empty())
362     sys::path::append(Path, SubdirParent);
363 
364   switch (Type) {
365   case SubDirectoryType::Bin:
366     if (VSLayout == ToolsetLayout::VS2017OrNewer) {
367       // MSVC ships with two linkers: a 32-bit x86 and 64-bit x86 linker.
368       // On x86, pick the linker that corresponds to the current process.
369       // On ARM64, pick the 32-bit x86 linker; the 64-bit one doesn't run
370       // on Windows 10.
371       //
372       // FIXME: Consider using IsWow64GuestMachineSupported to figure out
373       // if we can invoke the 64-bit linker. It's generally preferable
374       // because it won't run out of address-space.
375       const bool HostIsX64 =
376           Triple(sys::getProcessTriple()).getArch() == Triple::x86_64;
377       const char *const HostName = HostIsX64 ? "Hostx64" : "Hostx86";
378       sys::path::append(Path, "bin", HostName, SubdirName);
379     } else { // OlderVS or DevDivInternal
380       sys::path::append(Path, "bin", SubdirName);
381     }
382     break;
383   case SubDirectoryType::Include:
384     sys::path::append(Path, IncludeName);
385     break;
386   case SubDirectoryType::Lib:
387     sys::path::append(Path, "lib", SubdirName);
388     break;
389   }
390   return std::string(Path);
391 }
392 
393 bool useUniversalCRT(ToolsetLayout VSLayout, const std::string &VCToolChainPath,
394                      Triple::ArchType TargetArch, vfs::FileSystem &VFS) {
395   SmallString<128> TestPath(getSubDirectoryPath(
396       SubDirectoryType::Include, VSLayout, VCToolChainPath, TargetArch));
397   sys::path::append(TestPath, "stdlib.h");
398   return !VFS.exists(TestPath);
399 }
400 
401 bool getWindowsSDKDir(vfs::FileSystem &VFS, std::optional<StringRef> WinSdkDir,
402                       std::optional<StringRef> WinSdkVersion,
403                       std::optional<StringRef> WinSysRoot, std::string &Path,
404                       int &Major, std::string &WindowsSDKIncludeVersion,
405                       std::string &WindowsSDKLibVersion) {
406   // Trust /winsdkdir and /winsdkversion if present.
407   if (getWindowsSDKDirViaCommandLine(VFS, WinSdkDir, WinSdkVersion, WinSysRoot,
408                                      Path, Major, WindowsSDKIncludeVersion)) {
409     WindowsSDKLibVersion = WindowsSDKIncludeVersion;
410     return true;
411   }
412 
413   // FIXME: Try env vars (%WindowsSdkDir%, %UCRTVersion%) before going to
414   // registry.
415 
416   // Try the Windows registry.
417   std::string RegistrySDKVersion;
418   if (!getSystemRegistryString(
419           "SOFTWARE\\Microsoft\\Microsoft SDKs\\Windows\\$VERSION",
420           "InstallationFolder", Path, &RegistrySDKVersion))
421     return false;
422   if (Path.empty() || RegistrySDKVersion.empty())
423     return false;
424 
425   WindowsSDKIncludeVersion.clear();
426   WindowsSDKLibVersion.clear();
427   Major = 0;
428   std::sscanf(RegistrySDKVersion.c_str(), "v%d.", &Major);
429   if (Major <= 7)
430     return true;
431   if (Major == 8) {
432     // Windows SDK 8.x installs libraries in a folder whose names depend on the
433     // version of the OS you're targeting.  By default choose the newest, which
434     // usually corresponds to the version of the OS you've installed the SDK on.
435     const char *Tests[] = {"winv6.3", "win8", "win7"};
436     for (const char *Test : Tests) {
437       SmallString<128> TestPath(Path);
438       sys::path::append(TestPath, "Lib", Test);
439       if (VFS.exists(TestPath)) {
440         WindowsSDKLibVersion = Test;
441         break;
442       }
443     }
444     return !WindowsSDKLibVersion.empty();
445   }
446   if (Major == 10) {
447     if (!getWindows10SDKVersionFromPath(VFS, Path, WindowsSDKIncludeVersion))
448       return false;
449     WindowsSDKLibVersion = WindowsSDKIncludeVersion;
450     return true;
451   }
452   // Unsupported SDK version
453   return false;
454 }
455 
456 bool getUniversalCRTSdkDir(vfs::FileSystem &VFS,
457                            std::optional<StringRef> WinSdkDir,
458                            std::optional<StringRef> WinSdkVersion,
459                            std::optional<StringRef> WinSysRoot,
460                            std::string &Path, std::string &UCRTVersion) {
461   // If /winsdkdir is passed, use it as location for the UCRT too.
462   // FIXME: Should there be a dedicated /ucrtdir to override /winsdkdir?
463   int Major;
464   if (getWindowsSDKDirViaCommandLine(VFS, WinSdkDir, WinSdkVersion, WinSysRoot,
465                                      Path, Major, UCRTVersion))
466     return true;
467 
468   // FIXME: Try env vars (%UniversalCRTSdkDir%, %UCRTVersion%) before going to
469   // registry.
470 
471   // vcvarsqueryregistry.bat for Visual Studio 2015 queries the registry
472   // for the specific key "KitsRoot10". So do we.
473   if (!getSystemRegistryString(
474           "SOFTWARE\\Microsoft\\Windows Kits\\Installed Roots", "KitsRoot10",
475           Path, nullptr))
476     return false;
477 
478   return getWindows10SDKVersionFromPath(VFS, Path, UCRTVersion);
479 }
480 
481 bool findVCToolChainViaCommandLine(vfs::FileSystem &VFS,
482                                    std::optional<StringRef> VCToolsDir,
483                                    std::optional<StringRef> VCToolsVersion,
484                                    std::optional<StringRef> WinSysRoot,
485                                    std::string &Path, ToolsetLayout &VSLayout) {
486   // Don't validate the input; trust the value supplied by the user.
487   // The primary motivation is to prevent unnecessary file and registry access.
488   if (VCToolsDir || WinSysRoot) {
489     if (WinSysRoot) {
490       SmallString<128> ToolsPath(*WinSysRoot);
491       sys::path::append(ToolsPath, "VC", "Tools", "MSVC");
492       std::string ToolsVersion;
493       if (VCToolsVersion)
494         ToolsVersion = VCToolsVersion->str();
495       else
496         ToolsVersion = getHighestNumericTupleInDirectory(VFS, ToolsPath);
497       sys::path::append(ToolsPath, ToolsVersion);
498       Path = std::string(ToolsPath);
499     } else {
500       Path = VCToolsDir->str();
501     }
502     VSLayout = ToolsetLayout::VS2017OrNewer;
503     return true;
504   }
505   return false;
506 }
507 
508 bool findVCToolChainViaEnvironment(vfs::FileSystem &VFS, std::string &Path,
509                                    ToolsetLayout &VSLayout) {
510   // These variables are typically set by vcvarsall.bat
511   // when launching a developer command prompt.
512   if (std::optional<std::string> VCToolsInstallDir =
513           sys::Process::GetEnv("VCToolsInstallDir")) {
514     // This is only set by newer Visual Studios, and it leads straight to
515     // the toolchain directory.
516     Path = std::move(*VCToolsInstallDir);
517     VSLayout = ToolsetLayout::VS2017OrNewer;
518     return true;
519   }
520   if (std::optional<std::string> VCInstallDir =
521           sys::Process::GetEnv("VCINSTALLDIR")) {
522     // If the previous variable isn't set but this one is, then we've found
523     // an older Visual Studio. This variable is set by newer Visual Studios too,
524     // so this check has to appear second.
525     // In older Visual Studios, the VC directory is the toolchain.
526     Path = std::move(*VCInstallDir);
527     VSLayout = ToolsetLayout::OlderVS;
528     return true;
529   }
530 
531   // We couldn't find any VC environment variables. Let's walk through PATH and
532   // see if it leads us to a VC toolchain bin directory. If it does, pick the
533   // first one that we find.
534   if (std::optional<std::string> PathEnv = sys::Process::GetEnv("PATH")) {
535     SmallVector<StringRef, 8> PathEntries;
536     StringRef(*PathEnv).split(PathEntries, sys::EnvPathSeparator);
537     for (StringRef PathEntry : PathEntries) {
538       if (PathEntry.empty())
539         continue;
540 
541       SmallString<256> ExeTestPath;
542 
543       // If cl.exe doesn't exist, then this definitely isn't a VC toolchain.
544       ExeTestPath = PathEntry;
545       sys::path::append(ExeTestPath, "cl.exe");
546       if (!VFS.exists(ExeTestPath))
547         continue;
548 
549       // cl.exe existing isn't a conclusive test for a VC toolchain; clang also
550       // has a cl.exe. So let's check for link.exe too.
551       ExeTestPath = PathEntry;
552       sys::path::append(ExeTestPath, "link.exe");
553       if (!VFS.exists(ExeTestPath))
554         continue;
555 
556       // whatever/VC/bin --> old toolchain, VC dir is toolchain dir.
557       StringRef TestPath = PathEntry;
558       bool IsBin = sys::path::filename(TestPath).equals_insensitive("bin");
559       if (!IsBin) {
560         // Strip any architecture subdir like "amd64".
561         TestPath = sys::path::parent_path(TestPath);
562         IsBin = sys::path::filename(TestPath).equals_insensitive("bin");
563       }
564       if (IsBin) {
565         StringRef ParentPath = sys::path::parent_path(TestPath);
566         StringRef ParentFilename = sys::path::filename(ParentPath);
567         if (ParentFilename.equals_insensitive("VC")) {
568           Path = std::string(ParentPath);
569           VSLayout = ToolsetLayout::OlderVS;
570           return true;
571         }
572         if (ParentFilename.equals_insensitive("x86ret") ||
573             ParentFilename.equals_insensitive("x86chk") ||
574             ParentFilename.equals_insensitive("amd64ret") ||
575             ParentFilename.equals_insensitive("amd64chk")) {
576           Path = std::string(ParentPath);
577           VSLayout = ToolsetLayout::DevDivInternal;
578           return true;
579         }
580 
581       } else {
582         // This could be a new (>=VS2017) toolchain. If it is, we should find
583         // path components with these prefixes when walking backwards through
584         // the path.
585         // Note: empty strings match anything.
586         StringRef ExpectedPrefixes[] = {"",     "Host",  "bin", "",
587                                         "MSVC", "Tools", "VC"};
588 
589         auto It = sys::path::rbegin(PathEntry);
590         auto End = sys::path::rend(PathEntry);
591         for (StringRef Prefix : ExpectedPrefixes) {
592           if (It == End)
593             goto NotAToolChain;
594           if (!It->starts_with_insensitive(Prefix))
595             goto NotAToolChain;
596           ++It;
597         }
598 
599         // We've found a new toolchain!
600         // Back up 3 times (/bin/Host/arch) to get the root path.
601         StringRef ToolChainPath(PathEntry);
602         for (int i = 0; i < 3; ++i)
603           ToolChainPath = sys::path::parent_path(ToolChainPath);
604 
605         Path = std::string(ToolChainPath);
606         VSLayout = ToolsetLayout::VS2017OrNewer;
607         return true;
608       }
609 
610     NotAToolChain:
611       continue;
612     }
613   }
614   return false;
615 }
616 
617 bool findVCToolChainViaSetupConfig(vfs::FileSystem &VFS,
618                                    std::optional<StringRef> VCToolsVersion,
619                                    std::string &Path, ToolsetLayout &VSLayout) {
620 #if !defined(USE_MSVC_SETUP_API)
621   return false;
622 #else
623   // FIXME: This really should be done once in the top-level program's main
624   // function, as it may have already been initialized with a different
625   // threading model otherwise.
626   sys::InitializeCOMRAII COM(sys::COMThreadingMode::SingleThreaded);
627   HRESULT HR;
628 
629   // _com_ptr_t will throw a _com_error if a COM calls fail.
630   // The LLVM coding standards forbid exception handling, so we'll have to
631   // stop them from being thrown in the first place.
632   // The destructor will put the regular error handler back when we leave
633   // this scope.
634   struct SuppressCOMErrorsRAII {
635     static void __stdcall handler(HRESULT hr, IErrorInfo *perrinfo) {}
636 
637     SuppressCOMErrorsRAII() { _set_com_error_handler(handler); }
638 
639     ~SuppressCOMErrorsRAII() { _set_com_error_handler(_com_raise_error); }
640 
641   } COMErrorSuppressor;
642 
643   ISetupConfigurationPtr Query;
644   HR = Query.CreateInstance(__uuidof(SetupConfiguration));
645   if (FAILED(HR))
646     return false;
647 
648   IEnumSetupInstancesPtr EnumInstances;
649   HR = ISetupConfiguration2Ptr(Query)->EnumAllInstances(&EnumInstances);
650   if (FAILED(HR))
651     return false;
652 
653   ISetupInstancePtr Instance;
654   HR = EnumInstances->Next(1, &Instance, nullptr);
655   if (HR != S_OK)
656     return false;
657 
658   ISetupInstancePtr NewestInstance;
659   std::optional<uint64_t> NewestVersionNum;
660   do {
661     bstr_t VersionString;
662     uint64_t VersionNum;
663     HR = Instance->GetInstallationVersion(VersionString.GetAddress());
664     if (FAILED(HR))
665       continue;
666     HR = ISetupHelperPtr(Query)->ParseVersion(VersionString, &VersionNum);
667     if (FAILED(HR))
668       continue;
669     if (!NewestVersionNum || (VersionNum > NewestVersionNum)) {
670       NewestInstance = Instance;
671       NewestVersionNum = VersionNum;
672     }
673   } while ((HR = EnumInstances->Next(1, &Instance, nullptr)) == S_OK);
674 
675   if (!NewestInstance)
676     return false;
677 
678   bstr_t VCPathWide;
679   HR = NewestInstance->ResolvePath(L"VC", VCPathWide.GetAddress());
680   if (FAILED(HR))
681     return false;
682 
683   std::string VCRootPath;
684   convertWideToUTF8(std::wstring(VCPathWide), VCRootPath);
685 
686   std::string ToolsVersion;
687   if (VCToolsVersion.has_value()) {
688     ToolsVersion = *VCToolsVersion;
689   } else {
690     SmallString<256> ToolsVersionFilePath(VCRootPath);
691     sys::path::append(ToolsVersionFilePath, "Auxiliary", "Build",
692                       "Microsoft.VCToolsVersion.default.txt");
693 
694     auto ToolsVersionFile = MemoryBuffer::getFile(ToolsVersionFilePath);
695     if (!ToolsVersionFile)
696       return false;
697 
698     ToolsVersion = ToolsVersionFile->get()->getBuffer().rtrim();
699   }
700 
701 
702   SmallString<256> ToolchainPath(VCRootPath);
703   sys::path::append(ToolchainPath, "Tools", "MSVC", ToolsVersion);
704   auto Status = VFS.status(ToolchainPath);
705   if (!Status || !Status->isDirectory())
706     return false;
707 
708   Path = std::string(ToolchainPath.str());
709   VSLayout = ToolsetLayout::VS2017OrNewer;
710   return true;
711 #endif
712 }
713 
714 bool findVCToolChainViaRegistry(std::string &Path, ToolsetLayout &VSLayout) {
715   std::string VSInstallPath;
716   if (getSystemRegistryString(R"(SOFTWARE\Microsoft\VisualStudio\$VERSION)",
717                               "InstallDir", VSInstallPath, nullptr) ||
718       getSystemRegistryString(R"(SOFTWARE\Microsoft\VCExpress\$VERSION)",
719                               "InstallDir", VSInstallPath, nullptr)) {
720     if (!VSInstallPath.empty()) {
721       auto pos = VSInstallPath.find(R"(\Common7\IDE)");
722       if (pos == std::string::npos)
723         return false;
724       SmallString<256> VCPath(StringRef(VSInstallPath.c_str(), pos));
725       sys::path::append(VCPath, "VC");
726 
727       Path = std::string(VCPath);
728       VSLayout = ToolsetLayout::OlderVS;
729       return true;
730     }
731   }
732   return false;
733 }
734 
735 } // namespace llvm
736