Convert NT paths to DOSPath when resolving Symlinks

GetFinalPathNameByHandleW returns NTPaths (\\?\ Paths) which is an issue
as they don't match the paths stored in the internal dictionaries which
are DOS paths.

Author: gmittert

tools/SourceKit/lib/SwiftLang/SwiftLangSupport.cpp

@@ -911,36 +911,10 @@ void SwiftLangSupport::printMemberDeclDescription(const swift::ValueDecl *VD,
 
 std::string SwiftLangSupport::resolvePathSymlinks(StringRef FilePath) {
   std::string InputPath = FilePath;
-#if !defined(_WIN32)
-  char full_path[MAXPATHLEN];
-  if (const char *path = realpath(InputPath.c_str(), full_path))
-    return path;
-
-  return InputPath;
-#else
-  wchar_t full_path[MAX_PATH] = {0};
-  llvm::SmallVector<llvm::UTF16, 50> utf16Path;
-  llvm::convertUTF8ToUTF16String(InputPath.c_str(), utf16Path);
-
-  HANDLE fileHandle = CreateFileW(
-      (LPCWSTR)utf16Path.data(), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr,
-      OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr);
-
-  if (fileHandle == INVALID_HANDLE_VALUE)
+  llvm::SmallString<256> output;
+  if (llvm::sys::fs::real_path(InputPath, output))
     return InputPath;
-
-  DWORD numChars = GetFinalPathNameByHandleW(fileHandle, full_path, MAX_PATH,
-                                            FILE_NAME_NORMALIZED);
-  CloseHandle(fileHandle);
-  std::string utf8Path;
-  if (numChars > 0 && numChars <= MAX_PATH) {
-    llvm::ArrayRef<char> pathRef((const char *)full_path,
-                                 (const char *)(full_path + numChars));
-    return llvm::convertUTF16ToUTF8String(pathRef, utf8Path) ? utf8Path
-                                                             : InputPath;
-  }
-  return InputPath;
-#endif
+  return output.str();
 }
 
 void SwiftLangSupport::getStatistics(StatisticsReceiver receiver) {

tools/SourceKit/tools/sourcekitd-test/sourcekitd-test.cpp

@@ -49,35 +49,6 @@ using namespace sourcekitd_test;
 #if defined(_WIN32)
 namespace {
 int STDOUT_FILENO = _fileno(stdout);
-const constexpr size_t MAXPATHLEN = MAX_PATH + 1;
-char *realpath(const char *path, char *resolved_path) {
-  wchar_t full_path[MAXPATHLEN] = {0};
-  llvm::SmallVector<llvm::UTF16, 50> utf16Path;
-  llvm::convertUTF8ToUTF16String(path, utf16Path);
-
-  HANDLE fileHandle = CreateFileW(
-      (LPCWSTR)utf16Path.data(), 0, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr,
-      OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, nullptr);
-
-  if (fileHandle == INVALID_HANDLE_VALUE)
-    return nullptr;
-  DWORD success = GetFinalPathNameByHandleW(fileHandle, full_path, MAX_PATH,
-                                            FILE_NAME_NORMALIZED);
-  CloseHandle(fileHandle);
-  if (!success) return nullptr;
-
-  std::string utf8Path;
-  llvm::ArrayRef<char> pathRef((const char *)full_path,
-                               (const char *)(full_path + MAX_PATH));
-  if (!llvm::convertUTF16ToUTF8String(pathRef, utf8Path))
-    return nullptr;
-
-  if (!resolved_path) {
-    resolved_path = static_cast<char *>(malloc(utf8Path.length() + 1));
-  }
-  std::copy(std::begin(utf8Path), std::end(utf8Path), resolved_path);
-  return resolved_path;
-}
 }
 #endif
 
@@ -1445,9 +1416,9 @@ static void printCursorInfo(sourcekitd_variant_t Info, StringRef FilenameIn,
   }
 
   std::string Filename = FilenameIn;
-  char full_path[MAXPATHLEN];
-  if (const char *path = realpath(Filename.c_str(), full_path))
-    Filename = path;
+  llvm::SmallString<256> output;
+  if (!llvm::sys::fs::real_path(Filename, output))
+    Filename = output.str();
 
   const char *Kind = sourcekitd_uid_get_string_ptr(KindUID);
   const char *USR = sourcekitd_variant_dictionary_get_string(Info, KeyUSR);
@@ -1617,9 +1588,9 @@ static void printRangeInfo(sourcekitd_variant_t Info, StringRef FilenameIn,
   }
 
   std::string Filename = FilenameIn;
-  char full_path[MAXPATHLEN];
-  if (const char *path = realpath(Filename.c_str(), full_path))
-    Filename = path;
+  llvm::SmallString<256> output;
+  if (llvm::sys::fs::real_path(Filename, output))
+    Filename = output.str();
 
   sourcekitd_variant_t OffsetObj =
     sourcekitd_variant_dictionary_get_value(Info, KeyOffset);