Index: include/clang/Frontend/ASTConsumers.h
===================================================================
--- include/clang/Frontend/ASTConsumers.h
+++ include/clang/Frontend/ASTConsumers.h
@@ -40,6 +40,13 @@
                                              bool DumpDecls, bool Deserialize,
                                              bool DumpLookups);
 
+// AST dumper: dumps the raw AST in human-readable form to the given output
+// stream.
+std::unique_ptr<ASTConsumer> CreateASTDumper(std::unique_ptr<raw_ostream> OS,
+                                             StringRef FilterString,
+                                             bool DumpDecls, bool Deserialize,
+                                             bool DumpLookups);
+
 // AST Decl node lister: prints qualified names of all filterable AST Decl
 // nodes.
 std::unique_ptr<ASTConsumer> CreateASTDeclNodeLister();
Index: lib/Frontend/ASTConsumers.cpp
===================================================================
--- lib/Frontend/ASTConsumers.cpp
+++ lib/Frontend/ASTConsumers.cpp
@@ -142,8 +142,18 @@
                                                     bool DumpDecls,
                                                     bool Deserialize,
                                                     bool DumpLookups) {
+  return CreateASTDumper(nullptr, FilterString,
+                         DumpDecls, Deserialize, DumpLookups);
+}
+
+std::unique_ptr<ASTConsumer>
+clang::CreateASTDumper(std::unique_ptr<raw_ostream> Out,
+                       StringRef FilterString,
+                       bool DumpDecls,
+                       bool Deserialize,
+                       bool DumpLookups) {
   assert((DumpDecls || Deserialize || DumpLookups) && "nothing to dump");
-  return llvm::make_unique<ASTPrinter>(nullptr,
+  return llvm::make_unique<ASTPrinter>(std::move(Out),
                                        Deserialize ? ASTPrinter::DumpFull :
                                        DumpDecls ? ASTPrinter::Dump :
                                        ASTPrinter::None,