diff --git a/llvm/test/tools/llvm-orderfile/help.test b/llvm/test/tools/llvm-orderfile/help.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-orderfile/help.test
@@ -0,0 +1,3 @@
+RUN: llvm-orderfile --help 2>&1 | FileCheck %s
+CHECK: Generic Options:
+CHECK: llvm-orderfile Options:
diff --git a/llvm/test/tools/llvm-orderfile/mapping.data b/llvm/test/tools/llvm-orderfile/mapping.data
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-orderfile/mapping.data
@@ -0,0 +1,6 @@
+MD5 b84cbfeff0d303b4 too
+MD5 786da535fe6cbd2 zoo
+MD5 db956436e78dd5fa main
+MD5 b84cbfeff0d303b4 too
+MD5 786da535fe6cbd2 zoo
+MD5 db956436e78dd5fa main
diff --git a/llvm/test/tools/llvm-orderfile/order.data b/llvm/test/tools/llvm-orderfile/order.data
new file mode 100644
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000
GIT binary patch
literal 0
Hc$@<O00001

literal 0
Hc$@<O00001

diff --git a/llvm/test/tools/llvm-orderfile/read.test b/llvm/test/tools/llvm-orderfile/read.test
new file mode 100644
--- /dev/null
+++ b/llvm/test/tools/llvm-orderfile/read.test
@@ -0,0 +1,4 @@
+RUN: llvm-orderfile %S/order.data %S/mapping.data 2>&1 | FileCheck %s
+CHECK: main
+CHECK-NEXT: zoo
+CHECK-NEXT: too
diff --git a/llvm/tools/llvm-orderfile/CMakeLists.txt b/llvm/tools/llvm-orderfile/CMakeLists.txt
new file mode 100644
--- /dev/null
+++ b/llvm/tools/llvm-orderfile/CMakeLists.txt
@@ -0,0 +1,7 @@
+set(LLVM_LINK_COMPONENTS
+  Support
+  )
+
+add_llvm_tool(llvm-orderfile
+  llvm-orderfile.cpp
+  )
diff --git a/llvm/tools/llvm-orderfile/llvm-orderfile.cpp b/llvm/tools/llvm-orderfile/llvm-orderfile.cpp
new file mode 100644
--- /dev/null
+++ b/llvm/tools/llvm-orderfile/llvm-orderfile.cpp
@@ -0,0 +1,116 @@
+//===- llvm-cat.cpp - LLVM module concatenation utility -------------------===//
+//
+// 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 program is for testing features that rely on multi-module bitcode files.
+// It takes a list of input modules and uses them to create a multi-module
+// bitcode file.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cstring>
+
+using namespace llvm;
+
+cl::OptionCategory OrderfileCategory("llvm-orderfile Options");
+
+static cl::opt<std::string> OutputFilename("o",
+                                           cl::desc("Output filename"),
+                                           cl::value_desc("filename"),
+                                           cl::cat(OrderfileCategory));
+
+static cl::opt<std::string> BinaryOrderFile(cl::Positional,
+                                            cl::desc("<order file>"),
+                                            cl::cat(OrderfileCategory));
+
+static cl::opt<std::string> MappingFile(cl::Positional,
+                                        cl::desc("<mapping file>"),
+                                        cl::cat(OrderfileCategory));
+
+static cl::opt<bool> Verbose("v", cl::desc("verbose output"),
+                                  cl::cat(OrderfileCategory));
+
+
+static void DumpOrderFile(MemoryBuffer& BO, DenseMap<uint64_t, StringRef> const& Mapping, raw_ostream & OS)
+{
+  StringRef BinaryOrder = BO.getBuffer();
+  constexpr size_t BinaryOrderElementSize = 8;
+  for(size_t i = 0; i < BinaryOrder.size(); i += BinaryOrderElementSize) {
+    uint64_t Elt;
+    StringRef HexElt = BinaryOrder.substr(i, BinaryOrderElementSize);
+    std::memcpy(&Elt, HexElt.data(), sizeof(Elt));
+    auto Where = Mapping.find(Elt);
+    if (Where != Mapping.end())
+      OS << Where->second << "\n";
+    else if (Verbose && Elt) {
+      llvm::errs() << "no mapping found for entry ";
+      llvm::errs().write_hex(Elt);
+      llvm::errs() << "\n";
+    }
+  }
+}
+
+
+int main(int argc, char **argv) {
+  cl::HideUnrelatedOptions(OrderfileCategory);
+  cl::ParseCommandLineOptions(argc, argv, "Orderfile manipulation");
+
+  ExitOnError ExitOnErr("llvm-orderfile: ");
+
+  std::unique_ptr<MemoryBuffer> MF = ExitOnErr(
+      errorOrToExpected(MemoryBuffer::getFileOrSTDIN(MappingFile)));
+
+  StringRef MappingStream(MF->getBuffer());
+  SmallVector<StringRef> MappingLines;
+  MappingStream.split(MappingLines, /*Separator=*/'\n', /*MaxSplit=*/-1, /*KeepEmpty=*/false);
+
+  DenseMap<uint64_t, StringRef> Mapping;
+  SmallVector<StringRef> Tokens;
+  for(unsigned LineIndex = 0; LineIndex < MappingLines.size(); ++LineIndex) {
+    StringRef Line = MappingLines[LineIndex];
+    Line.split(Tokens, /*Separator=*/' ');
+    if (Tokens.size() != 3) {
+      llvm::errs() << MappingFile << ':' << (1 + LineIndex) << ": has invalid format\n";
+      llvm::errs() << "when parsing: " << Line << "\n";
+      return 1;
+    }
+    uint64_t Val;
+    Tokens[1].getAsInteger(16, Val);
+    Mapping[Val] = Tokens[2];
+    Tokens.clear();
+  }
+
+  if(Verbose)
+    llvm::errs() << "Found " << Mapping.size() << " mappings.\n";
+
+  std::unique_ptr<MemoryBuffer> BO = ExitOnErr(
+      errorOrToExpected(MemoryBuffer::getFile(BinaryOrderFile)));
+
+  if (OutputFilename.empty()) {
+    DumpOrderFile(*BO, Mapping, llvm::outs());
+  }
+  else {
+    std::error_code EC;
+    raw_fd_ostream OS(OutputFilename, EC, sys::fs::OpenFlags::OF_None);
+    if (EC) {
+      errs() << argv[0] << ": cannot open " << OutputFilename << " for writing: "
+             << EC.message();
+      return 1;
+    }
+    DumpOrderFile(*BO, Mapping, OS);
+  }
+
+
+  return 0;
+}