[SystemZ][z/OS] Add new openFileForReadBinary function, and pass IsText parameter to getBufferForFile (#111723)

This patch adds an IsText parameter to the following getBufferForFile,
getBufferForFileImpl. We introduce a new virtual function
openFileForReadBinary which defaults to openFileForRead except in
RealFileSystem which uses the OF_None flag instead of OF_Text.

The default is set to OF_Text instead of OF_None, this change in value
does not affect any other platforms other than z/OS. Setting this
parameter correctly is required to open files on z/OS in the correct
encoding. The IsText parameter is based on the context of where we open
files, for example, in the ASTReader, HeaderMap requires that files
always be opened in binary even though they might be tagged as text.

1 files changed, 8 insertions, 6 deletions

diff --git a/clang/lib/Basic/FileSystemStatCache.cpp b/clang/lib/Basic/FileSystemStatCache.cpp
index 415a4e2..183eea0 100644
--- a/clang/lib/Basic/FileSystemStatCache.cpp
+++ b/clang/lib/Basic/FileSystemStatCache.cpp
@@ -30,11 +30,12 @@ void FileSystemStatCache::anchor() {}
 /// success for directories (not files).  On a successful file lookup, the
 /// implementation can optionally fill in FileDescriptor with a valid
 /// descriptor and the client guarantees that it will close it.
-std::error_code
-FileSystemStatCache::get(StringRef Path, llvm::vfs::Status &Status,
-                         bool isFile, std::unique_ptr<llvm::vfs::File> *F,
-                         FileSystemStatCache *Cache,
-                         llvm::vfs::FileSystem &FS) {
+std::error_code FileSystemStatCache::get(StringRef Path,
+                                         llvm::vfs::Status &Status, bool isFile,
+                                         std::unique_ptr<llvm::vfs::File> *F,
+                                         FileSystemStatCache *Cache,
+                                         llvm::vfs::FileSystem &FS,
+                                         bool IsText) {
   bool isForDir = !isFile;
   std::error_code RetCode;
 
@@ -58,7 +59,8 @@ FileSystemStatCache::get(StringRef Path, llvm::vfs::Status &Status,
     //
     // Because of this, check to see if the file exists with 'open'.  If the
     // open succeeds, use fstat to get the stat info.
-    auto OwnedFile = FS.openFileForRead(Path);
+    auto OwnedFile =
+        IsText ? FS.openFileForRead(Path) : FS.openFileForReadBinary(Path);
 
     if (!OwnedFile) {
       // If the open fails, our "stat" fails.