4 files changed, 21 insertions, 24 deletions
diff --git a/clang/lib/Basic/FileManager.cpp b/clang/lib/Basic/FileManager.cpp
index c4eae6a..1cb52d5 100644
--- a/clang/lib/Basic/FileManager.cpp
+++ b/clang/lib/Basic/FileManager.cpp
@@ -123,16 +123,16 @@ FileManager::getDirectoryRef(StringRef DirName, bool CacheFailure) {
       DirName != llvm::sys::path::root_path(DirName) &&
       llvm::sys::path::is_separator(DirName.back()))
     DirName = DirName.substr(0, DirName.size()-1);
-#ifdef _WIN32
-  // Fixing a problem with "clang C:test.c" on Windows.
-  // Stat("C:") does not recognize "C:" as a valid directory
-  std::string DirNameStr;
-  if (DirName.size() > 1 && DirName.back() == ':' &&
-      DirName.equals_insensitive(llvm::sys::path::root_name(DirName))) {
-    DirNameStr = DirName.str() + '.';
-    DirName = DirNameStr;
+  if (is_style_windows(llvm::sys::path::Style::native)) {
+    // Fixing a problem with "clang C:test.c" on Windows.
+    // Stat("C:") does not recognize "C:" as a valid directory
+    std::string DirNameStr;
+    if (DirName.size() > 1 && DirName.back() == ':' &&
+        DirName.equals_insensitive(llvm::sys::path::root_name(DirName))) {
+      DirNameStr = DirName.str() + '.';
+      DirName = DirNameStr;
+    }
   }
-#endif
 
   ++NumDirLookups;
 
diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 5b64ca8..2ddb753 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4899,11 +4899,11 @@ const char *Driver::GetNamedOutputPath(Compilation &C, const JobAction &JA,
                                        bool MultipleArchs,
                                        StringRef OffloadingPrefix) const {
   std::string BoundArch = OrigBoundArch.str();
-#if defined(_WIN32)
-  // BoundArch may contains ':', which is invalid in file names on Windows,
-  // therefore replace it with '%'.
-  std::replace(BoundArch.begin(), BoundArch.end(), ':', '@');
-#endif
+  if (is_style_windows(llvm::sys::path::Style::native)) {
+    // BoundArch may contains ':', which is invalid in file names on Windows,
+    // therefore replace it with '%'.
+    std::replace(BoundArch.begin(), BoundArch.end(), ':', '@');
+  }
 
   llvm::PrettyStackTraceString CrashInfo("Computing output path");
   // Output to a user requested destination?
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index df205c3..debaf9e 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -169,10 +169,11 @@ static const DriverSuffix *FindDriverSuffix(StringRef ProgName, size_t &Pos) {
 /// present and lower-casing the string on Windows.
 static std::string normalizeProgramName(llvm::StringRef Argv0) {
   std::string ProgName = std::string(llvm::sys::path::stem(Argv0));
-#ifdef _WIN32
-  // Transform to lowercase for case insensitive file systems.
-  std::transform(ProgName.begin(), ProgName.end(), ProgName.begin(), ::tolower);
-#endif
+  if (is_style_windows(llvm::sys::path::Style::native)) {
+    // Transform to lowercase for case insensitive file systems.
+    std::transform(ProgName.begin(), ProgName.end(), ProgName.begin(),
+                   ::tolower);
+  }
   return ProgName;
 }
 
diff --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index ea14921..1c2439a 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -2012,20 +2012,16 @@ Preprocessor::ImportAction Preprocessor::HandleHeaderIncludeOrImport(
   SourceLocation FilenameLoc = FilenameTok.getLocation();
   StringRef LookupFilename = Filename;
 
-#ifdef _WIN32
-  llvm::sys::path::Style BackslashStyle = llvm::sys::path::Style::windows;
-#else
   // Normalize slashes when compiling with -fms-extensions on non-Windows. This
   // is unnecessary on Windows since the filesystem there handles backslashes.
   SmallString<128> NormalizedPath;
-  llvm::sys::path::Style BackslashStyle = llvm::sys::path::Style::posix;
-  if (LangOpts.MicrosoftExt) {
+  llvm::sys::path::Style BackslashStyle = llvm::sys::path::Style::native;
+  if (is_style_posix(BackslashStyle) && LangOpts.MicrosoftExt) {
     NormalizedPath = Filename.str();
     llvm::sys::path::native(NormalizedPath);
     LookupFilename = NormalizedPath;
     BackslashStyle = llvm::sys::path::Style::windows;
   }
-#endif
 
   Optional<FileEntryRef> File = LookupHeaderIncludeOrImport(
       CurDir, Filename, FilenameLoc, FilenameRange, FilenameTok,