[SystemZ][z/OS] Add new openFileForReadBinary function, and pass IsText parameter to getBufferForFile

clang/include/clang/Basic/FileManager.h

@@ -290,23 +290,28 @@ class FileManager : public RefCountedBase<FileManager> {
 
   /// Open the specified file as a MemoryBuffer, returning a new
   /// MemoryBuffer if successful, otherwise returning null.
+  /// The IsText parameter controls whether the file should be opened as a text
+  /// or binary file, and should be set to false if the file contents should be
+  /// treated as binary.
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
   getBufferForFile(FileEntryRef Entry, bool isVolatile = false,
                    bool RequiresNullTerminator = true,
-                   std::optional<int64_t> MaybeLimit = std::nullopt);
+                   std::optional<int64_t> MaybeLimit = std::nullopt,
+                   bool IsText = true);
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
   getBufferForFile(StringRef Filename, bool isVolatile = false,
                    bool RequiresNullTerminator = true,
-                   std::optional<int64_t> MaybeLimit = std::nullopt) const {
+                   std::optional<int64_t> MaybeLimit = std::nullopt,
+                   bool IsText = true) const {
     return getBufferForFileImpl(Filename,
                                 /*FileSize=*/MaybeLimit.value_or(-1),
-                                isVolatile, RequiresNullTerminator);
+                                isVolatile, RequiresNullTerminator, IsText);
   }
 
 private:
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
   getBufferForFileImpl(StringRef Filename, int64_t FileSize, bool isVolatile,
-                       bool RequiresNullTerminator) const;
+                       bool RequiresNullTerminator, bool IsText) const;
 
   DirectoryEntry *&getRealDirEntry(const llvm::vfs::Status &Status);
 

clang/lib/Basic/FileManager.cpp

@@ -531,7 +531,7 @@ void FileManager::fillRealPathName(FileEntry *UFE, llvm::StringRef FileName) {
 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
 FileManager::getBufferForFile(FileEntryRef FE, bool isVolatile,
                               bool RequiresNullTerminator,
-                              std::optional<int64_t> MaybeLimit) {
+                              std::optional<int64_t> MaybeLimit, bool IsText) {
   const FileEntry *Entry = &FE.getFileEntry();
   // If the content is living on the file entry, return a reference to it.
   if (Entry->Content)
@@ -558,21 +558,21 @@ FileManager::getBufferForFile(FileEntryRef FE, bool isVolatile,
 
   // Otherwise, open the file.
   return getBufferForFileImpl(Filename, FileSize, isVolatile,
-                              RequiresNullTerminator);
+                              RequiresNullTerminator, IsText);
 }
 
 llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
 FileManager::getBufferForFileImpl(StringRef Filename, int64_t FileSize,
-                                  bool isVolatile,
-                                  bool RequiresNullTerminator) const {
+                                  bool isVolatile, bool RequiresNullTerminator,
+                                  bool IsText) const {
   if (FileSystemOpts.WorkingDir.empty())
     return FS->getBufferForFile(Filename, FileSize, RequiresNullTerminator,
-                                isVolatile);
+                                isVolatile, IsText);
 
   SmallString<128> FilePath(Filename);
   FixupRelativePath(FilePath);
   return FS->getBufferForFile(FilePath, FileSize, RequiresNullTerminator,
-                              isVolatile);
+                              isVolatile, IsText);
 }
 
 /// getStatValue - Get the 'stat' information for the specified path,

clang/lib/Lex/HeaderMap.cpp

@@ -54,7 +54,10 @@ std::unique_ptr<HeaderMap> HeaderMap::Create(FileEntryRef FE, FileManager &FM) {
   unsigned FileSize = FE.getSize();
   if (FileSize <= sizeof(HMapHeader)) return nullptr;
 
-  auto FileBuffer = FM.getBufferForFile(FE);
+  auto FileBuffer =
+      FM.getBufferForFile(FE, /*IsVolatile=*/false,
+                          /*RequiresNullTerminator=*/true,
+                          /*MaybeList=*/std::nullopt, /*IsText=*/false);
   if (!FileBuffer || !*FileBuffer)
     return nullptr;
   bool NeedsByteSwap;

clang/lib/Serialization/ASTReader.cpp

@@ -5333,7 +5333,9 @@ std::string ASTReader::getOriginalSourceFile(
     const PCHContainerReader &PCHContainerRdr, DiagnosticsEngine &Diags) {
   // Open the AST file.
   auto Buffer = FileMgr.getBufferForFile(ASTFileName, /*IsVolatile=*/false,
-                                         /*RequiresNullTerminator=*/false);
+                                         /*RequiresNullTerminator=*/false,
+                                         /*MaybeLimit=*/std::nullopt,
+                                         /*IsText=*/false);
   if (!Buffer) {
     Diags.Report(diag::err_fe_unable_to_read_pch_file)
         << ASTFileName << Buffer.getError().message();

llvm/include/llvm/Support/VirtualFileSystem.h

@@ -271,15 +271,28 @@ class FileSystem : public llvm::ThreadSafeRefCountedBase<FileSystem>,
   /// Get the status of the entry at \p Path, if one exists.
   virtual llvm::ErrorOr<Status> status(const Twine &Path) = 0;
 
-  /// Get a \p File object for the file at \p Path, if one exists.
+  /// Get a \p File object for the text file at \p Path, if one exists.
   virtual llvm::ErrorOr<std::unique_ptr<File>>
   openFileForRead(const Twine &Path) = 0;
 
+  /// Get a \p File object for the binary file at \p Path, if one exists.
+  /// Some non-ascii based file systems perform encoding conversions
+  /// when reading as a text file, and this function should be used if
+  /// a file's bytes should be read as-is. On most filesystems, this
+  /// is the same behaviour as openFileForRead.
+  virtual llvm::ErrorOr<std::unique_ptr<File>>
+  openFileForReadBinary(const Twine &Path) {
+    return openFileForRead(Path);
+  }
+
   /// This is a convenience method that opens a file, gets its content and then
   /// closes the file.
+  /// The IsText parameter is used to distinguish whether the file should be
+  /// opened as a binary or text file.
   llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
   getBufferForFile(const Twine &Name, int64_t FileSize = -1,
-                   bool RequiresNullTerminator = true, bool IsVolatile = false);
+                   bool RequiresNullTerminator = true, bool IsVolatile = false,
+                   bool IsText = true);
 
   /// Get a directory_iterator for \p Dir.
   /// \note The 'end' iterator is directory_iterator().

llvm/lib/Support/VirtualFileSystem.cpp

@@ -117,8 +117,9 @@ FileSystem::~FileSystem() = default;
 
 ErrorOr<std::unique_ptr<MemoryBuffer>>
 FileSystem::getBufferForFile(const llvm::Twine &Name, int64_t FileSize,
-                             bool RequiresNullTerminator, bool IsVolatile) {
-  auto F = openFileForRead(Name);
+                             bool RequiresNullTerminator, bool IsVolatile,
+                             bool IsText) {
+  auto F = IsText ? openFileForRead(Name) : openFileForReadBinary(Name);
   if (!F)
     return F.getError();
 
@@ -279,6 +280,8 @@ class RealFileSystem : public FileSystem {
 
   ErrorOr<Status> status(const Twine &Path) override;
   ErrorOr<std::unique_ptr<File>> openFileForRead(const Twine &Path) override;
+  ErrorOr<std::unique_ptr<File>>
+  openFileForReadBinary(const Twine &Path) override;
   directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
 
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
@@ -302,6 +305,17 @@ class RealFileSystem : public FileSystem {
     return Storage;
   }
 
+  ErrorOr<std::unique_ptr<File>>
+  openFileForReadWithFlags(const Twine &Name, sys::fs::OpenFlags Flags) {
+    SmallString<256> RealName, Storage;
+    Expected<file_t> FDOrErr = sys::fs::openNativeFileForRead(
+        adjustPath(Name, Storage), Flags, &RealName);
+    if (!FDOrErr)
+      return errorToErrorCode(FDOrErr.takeError());
+    return std::unique_ptr<File>(
+        new RealFile(*FDOrErr, Name.str(), RealName.str()));
+  }
+
   struct WorkingDirectory {
     // The current working directory, without symlinks resolved. (echo $PWD).
     SmallString<128> Specified;
@@ -324,13 +338,12 @@ ErrorOr<Status> RealFileSystem::status(const Twine &Path) {
 
 ErrorOr<std::unique_ptr<File>>
 RealFileSystem::openFileForRead(const Twine &Name) {
-  SmallString<256> RealName, Storage;
-  Expected<file_t> FDOrErr = sys::fs::openNativeFileForRead(
-      adjustPath(Name, Storage), sys::fs::OF_None, &RealName);
-  if (!FDOrErr)
-    return errorToErrorCode(FDOrErr.takeError());
-  return std::unique_ptr<File>(
-      new RealFile(*FDOrErr, Name.str(), RealName.str()));
+  return openFileForReadWithFlags(Name, sys::fs::OF_Text);
+}
+
+ErrorOr<std::unique_ptr<File>>
+RealFileSystem::openFileForReadBinary(const Twine &Name) {
+  return openFileForReadWithFlags(Name, sys::fs::OF_None);
 }
 
 llvm::ErrorOr<std::string> RealFileSystem::getCurrentWorkingDirectory() const {