[SystemZ][z/OS] Propagate IsText parameter to open text files as text (#107906)

This patch adds an IsText parameter to the following functions
openFileForRead, getBufferForFile, getBufferForFileImpl and determines
whether a file is text by querying the file tag on z/OS. 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.

1 files changed, 12 insertions, 2 deletions

diff --git a/clang/lib/Basic/SourceManager.cpp b/clang/lib/Basic/SourceManager.cpp
index 65a8a72..fe3aff7 100644
--- a/clang/lib/Basic/SourceManager.cpp
+++ b/clang/lib/Basic/SourceManager.cpp
@@ -121,8 +121,18 @@ ContentCache::getBufferOrNone(DiagnosticsEngine &Diag, FileManager &FM,
   // Start with the assumption that the buffer is invalid to simplify early
   // return paths.
   IsBufferInvalid = true;
-
-  auto BufferOrError = FM.getBufferForFile(*ContentsEntry, IsFileVolatile);
+  bool IsText = false;
+
+#ifdef __MVS__
+  // If the file is tagged with a text ccsid, it may require autoconversion.
+  llvm::ErrorOr<bool> IsFileText =
+      llvm::iszOSTextFile(ContentsEntry->getName().data());
+  if (IsFileText)
+    IsText = *IsFileText;
+#endif
+
+  auto BufferOrError = FM.getBufferForFile(
+      *ContentsEntry, IsFileVolatile, /*RequiresNullTerminator=*/true, IsText);
 
   // If we were unable to open the file, then we are in an inconsistent
   // situation where the content cache referenced a file which no longer