1 files changed, 75 insertions, 0 deletions
diff --git a/llvm/lib/Support/Errno.cpp b/llvm/lib/Support/Errno.cpp
new file mode 100644
index 000000000000..d18231c6ebf5
--- /dev/null
+++ b/llvm/lib/Support/Errno.cpp
@@ -0,0 +1,75 @@
+//===- Errno.cpp - errno support --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the errno wrappers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Errno.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/raw_ostream.h"
+#include <string.h>
+
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+namespace llvm {
+namespace sys {
+
+#if HAVE_ERRNO_H
+std::string StrError() {
+  return StrError(errno);
+}
+#endif  // HAVE_ERRNO_H
+
+std::string StrError(int errnum) {
+  std::string str;
+  if (errnum == 0)
+    return str;
+#if defined(HAVE_STRERROR_R) || HAVE_DECL_STRERROR_S
+  const int MaxErrStrLen = 2000;
+  char buffer[MaxErrStrLen];
+  buffer[0] = '\0';
+#endif
+
+#ifdef HAVE_STRERROR_R
+  // strerror_r is thread-safe.
+#if defined(__GLIBC__) && defined(_GNU_SOURCE)
+  // glibc defines its own incompatible version of strerror_r
+  // which may not use the buffer supplied.
+  str = strerror_r(errnum, buffer, MaxErrStrLen - 1);
+#else
+  strerror_r(errnum, buffer, MaxErrStrLen - 1);
+  str = buffer;
+#endif
+#elif HAVE_DECL_STRERROR_S // "Windows Secure API"
+  strerror_s(buffer, MaxErrStrLen - 1, errnum);
+  str = buffer;
+#elif defined(HAVE_STRERROR)
+  // Copy the thread un-safe result of strerror into
+  // the buffer as fast as possible to minimize impact
+  // of collision of strerror in multiple threads.
+  str = strerror(errnum);
+#else
+  // Strange that this system doesn't even have strerror
+  // but, oh well, just use a generic message
+  raw_string_ostream stream(str);
+  stream << "Error #" << errnum;
+  stream.flush();
+#endif
+  return str;
+}
+
+}  // namespace sys
+}  // namespace llvm