1 files changed, 39 insertions, 2 deletions
diff --git a/llvm/lib/Support/InitLLVM.cpp b/llvm/lib/Support/InitLLVM.cpp
index 2b7173b28940..7f475f42f3cb 100644
--- a/llvm/lib/Support/InitLLVM.cpp
+++ b/llvm/lib/Support/InitLLVM.cpp
@@ -8,6 +8,8 @@
 
 #include "llvm/Support/InitLLVM.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/AutoConvert.h"
+#include "llvm/Support/Error.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PrettyStackTrace.h"
@@ -15,15 +17,31 @@
 #include "llvm/Support/SwapByteOrder.h"
 
 #ifdef _WIN32
-#include "llvm/Support/Error.h"
 #include "llvm/Support/Windows/WindowsSupport.h"
 #endif
 
+#ifdef __MVS__
+#include <unistd.h>
+
+void CleanupStdHandles(void *Cookie) {
+  llvm::raw_ostream *Outs = &llvm::outs(), *Errs = &llvm::errs();
+  Outs->flush();
+  Errs->flush();
+  llvm::restoreStdHandleAutoConversion(STDIN_FILENO);
+  llvm::restoreStdHandleAutoConversion(STDOUT_FILENO);
+  llvm::restoreStdHandleAutoConversion(STDERR_FILENO);
+}
+#endif
+
 using namespace llvm;
 using namespace llvm::sys;
 
 InitLLVM::InitLLVM(int &Argc, const char **&Argv,
                    bool InstallPipeSignalExitHandler) {
+#ifdef __MVS__
+  // Bring stdin/stdout/stderr into a known state.
+  sys::AddSignalHandler(CleanupStdHandles, nullptr);
+#endif
   if (InstallPipeSignalExitHandler)
     // The pipe signal handler must be installed before any other handlers are
     // registered. This is because the Unix \ref RegisterHandlers function does
@@ -37,6 +55,20 @@ InitLLVM::InitLLVM(int &Argc, const char **&Argv,
   sys::PrintStackTraceOnErrorSignal(Argv[0]);
   install_out_of_memory_new_handler();
 
+#ifdef __MVS__
+
+  // We use UTF-8 as the internal character encoding. On z/OS, all external
+  // output is encoded in EBCDIC. In order to be able to read all
+  // error messages, we turn conversion to EBCDIC on for stderr fd.
+  std::string Banner = std::string(Argv[0]) + ": ";
+  ExitOnError ExitOnErr(Banner);
+
+  // If turning on conversion for stderr fails then the error message
+  // may be garbled. There is no solution to this problem.
+  ExitOnErr(errorCodeToError(llvm::enableAutoConversion(STDERR_FILENO)));
+  ExitOnErr(errorCodeToError(llvm::enableAutoConversion(STDOUT_FILENO)));
+#endif
+
 #ifdef _WIN32
   // We use UTF-8 as the internal character encoding. On Windows,
   // arguments passed to main() may not be encoded in UTF-8. In order
@@ -61,4 +93,9 @@ InitLLVM::InitLLVM(int &Argc, const char **&Argv,
 #endif
 }
 
-InitLLVM::~InitLLVM() { llvm_shutdown(); }
+InitLLVM::~InitLLVM() {
+#ifdef __MVS__
+  CleanupStdHandles(nullptr);
+#endif
+  llvm_shutdown();
+}