Index: include/llvm/Support/Compression.h
===================================================================
--- include/llvm/Support/Compression.h
+++ include/llvm/Support/Compression.h
@@ -52,6 +52,8 @@
 
 uint32_t crc32(StringRef Buffer);
 
+StringRef toString(Status Stat);
+
 }  // End of namespace zlib
 
 } // End of namespace llvm
Index: lib/Support/Compression.cpp
===================================================================
--- lib/Support/Compression.cpp
+++ lib/Support/Compression.cpp
@@ -87,6 +87,25 @@
   return ::crc32(0, (const Bytef *)Buffer.data(), Buffer.size());
 }
 
+StringRef zlib::toString(zlib::Status Stat) {
+  switch (Stat) {
+  case zlib::StatusOK:
+    return "";
+  case zlib::StatusUnsupported:
+    return "zlib is unavailable";
+  case zlib::StatusOutOfMemory:
+    return "there was not enough memory";
+  case zlib::StatusBufferTooShort:
+    return "there was not enough room in the output buffer";
+  case zlib::StatusInvalidArg:
+    return "invalid input parameter";
+  case zlib::StatusInvalidData:
+    return "data was corrupted or incomplete";
+  default:
+    llvm_unreachable("zlib status unknown");
+  }
+}
+
 #else
 bool zlib::isAvailable() { return false; }
 zlib::Status zlib::compress(StringRef InputBuffer,
@@ -106,5 +125,8 @@
 uint32_t zlib::crc32(StringRef Buffer) {
   llvm_unreachable("zlib::crc32 is unavailable");
 }
+StringRef zlib::toString(zlib::Status Stat) {
+  llvm_unreachable("zlib::toString is unavailable");
+}
 #endif