Index: clang-rename/tool/ClangRename.cpp
===================================================================
--- clang-rename/tool/ClangRename.cpp
+++ clang-rename/tool/ClangRename.cpp
@@ -56,6 +56,29 @@
 static int renameAllMain(int argc, const char *argv[]);
 static int helpMain(int argc, const char *argv[]);
 
+/// \brief An oldname -> newname rename.
+struct RenameAllInfo {
+  std::string OldName;
+  std::string NewName;
+};
+
+LLVM_YAML_IS_SEQUENCE_VECTOR(RenameAllInfo)
+
+namespace llvm {
+namespace yaml {
+
+/// \brief Specialized MappingTraits to describe how a RenameAllInfo is /
+/// (de)serialized.
+template <> struct MappingTraits<RenameAllInfo> {
+  static void mapping(IO &IO, RenameAllInfo &Info) {
+    IO.mapRequired("OldName", Info.OldName);
+    IO.mapRequired("NewName", Info.NewName);
+  }
+};
+
+} // end namespace yaml
+} // end namespace llvm
+
 int main(int argc, const char **argv) {
   if (argc > 1) {
     using MainFunction = std::function<int(int, const char *[])>;
@@ -91,7 +114,7 @@
 
   cl::list<std::string> NewNames(
       "new-name", cl::desc("The new name to change the symbol to."),
-      (isRenameAll ? cl::OneOrMore : cl::Required), cl::cat(*Category));
+      (isRenameAll ? cl::ZeroOrMore : cl::Required), cl::cat(*Category));
   cl::list<unsigned> SymbolOffsets(
       "offset",
       cl::desc("Locates the symbol by offset as opposed to <line>:<column>."),
@@ -114,11 +137,37 @@
   cl::opt<std::string> ExportFixes(
       "export-fixes", cl::desc("YAML file to store suggested fixes in."),
       cl::value_desc("filename"), cl::cat(*Category));
+  cl::opt<std::string> Input(
+      "input", cl::desc("YAML file to load oldname-newname pairs from."),
+      cl::Optional, cl::cat(ClangRenameAllCategory));
 
   tooling::CommonOptionsParser OP(argc, argv, *Category, Usage);
 
+  if (!Input.empty()) {
+    // Populate OldNames and NewNames from a YAML file.
+    auto Buffer = llvm::MemoryBuffer::getFile(Input);
+    if (!Buffer) {
+      errs() << "clang-rename: failed to read " << Input << ": "
+             << Buffer.getError().message() << "\n";
+      exit(1);
+    }
+
+    std::vector<RenameAllInfo> Infos;
+    llvm::yaml::Input YAML(Buffer.get()->getBuffer());
+    YAML >> Infos;
+    for (const auto &Info : Infos) {
+      OldNames.push_back(Info.OldName);
+      NewNames.push_back(Info.NewName);
+    }
+  }
+
   // Check the arguments for correctness.
 
+  if (NewNames.empty()) {
+    errs() << "clang-rename: either -new-name or -input is required.\n\n";
+    exit(1);
+  }
+
   // Check if NewNames is a valid identifier in C++17.
   for (const auto &NewName : NewNames) {
     LangOptions Options;
Index: docs/clang-rename.rst
===================================================================
--- docs/clang-rename.rst
+++ docs/clang-rename.rst
@@ -50,6 +50,23 @@
   $ clang-rename rename-all -old-name=foo -new-name=bar test.cpp
 
 
+Alternatively, old name / new name pairs can be put into a YAML file:
+
+.. code-block:: yaml
+
+  ---
+  - OldName:        foo
+    NewName:        bar
+  ...
+
+
+That way you can avoid spelling out all the names as commandline arguments:
+
+.. code-block:: console
+
+  $ clang-rename rename-all -input=test.yaml test.cpp
+
+
 The tool currently supports renaming actions inside a single Translation Unit
 only. It is planned to extend the tool's functionality to support multi-TU
 renaming actions in the future.
@@ -125,6 +142,7 @@
     -extra-arg=<string>        - Additional argument to append to the compiler command line
     -extra-arg-before=<string> - Additional argument to prepend to the compiler command line
     -i                         - Overwrite edited <file>s.
+    -input=<string>            - YAML file to load oldname-newname pairs from.
     -new-name=<string>         - The new name to change the symbol to.
     -offset=<uint>             - Locates the symbol by offset as opposed to <line>:<column>.
     -old-name=<string>         - The fully qualified name of the symbol, if -offset is not used.
Index: test/clang-rename/ClassTestMultiByNameYAML.cpp
===================================================================
--- /dev/null
+++ test/clang-rename/ClassTestMultiByNameYAML.cpp
@@ -0,0 +1,8 @@
+// RUN: cat %s > %t.cpp
+// RUN: clang-rename rename-all -input %s.yaml %t.cpp -i --
+// RUN: sed 's,//.*,,' %t.cpp | FileCheck %s
+class Foo1 { // CHECK: class Bar1
+};
+
+class Foo2 { // CHECK: class Bar2
+};
Index: test/clang-rename/ClassTestMultiByNameYAML.cpp.yaml
===================================================================
--- /dev/null
+++ test/clang-rename/ClassTestMultiByNameYAML.cpp.yaml
@@ -0,0 +1,6 @@
+---
+- OldName:        Foo1
+  NewName:        Bar1
+- OldName:        Foo2
+  NewName:        Bar2
+...