Index: include/llvm/ExecutionEngine/ObjectMemoryBuffer.h
===================================================================
--- include/llvm/ExecutionEngine/ObjectMemoryBuffer.h
+++ include/llvm/ExecutionEngine/ObjectMemoryBuffer.h
@@ -56,6 +56,8 @@
 private:
   SmallVector<char, 0> SV;
   std::string BufferName;
+  // FIXME: both ThinLTOCodeGenerator.cpp and MCJIT.cpp use this class.
+  void anchor() override{};
 };
 
 } // namespace llvm
Index: include/llvm/ExecutionEngine/RTDyldMemoryManager.h
===================================================================
--- include/llvm/ExecutionEngine/RTDyldMemoryManager.h
+++ include/llvm/ExecutionEngine/RTDyldMemoryManager.h
@@ -47,6 +47,9 @@
   /// newly loaded object.
   virtual void notifyObjectLoaded(ExecutionEngine *EE,
                                   const object::ObjectFile &) {}
+
+private:
+  void anchor() override;
 };
 
 // RuntimeDyld clients often want to handle the memory management of
@@ -142,6 +145,9 @@
   };
   typedef std::vector<EHFrame> EHFrameInfos;
   EHFrameInfos EHFrames;
+
+private:
+  void anchor() override;
 };
 
 // Create wrappers for C Binding types (see CBindingWrapping.h).
Index: include/llvm/ExecutionEngine/SectionMemoryManager.h
===================================================================
--- include/llvm/ExecutionEngine/SectionMemoryManager.h
+++ include/llvm/ExecutionEngine/SectionMemoryManager.h
@@ -182,6 +182,8 @@
   std::error_code applyMemoryGroupPermissions(MemoryGroup &MemGroup,
                                               unsigned Permissions);
 
+  void anchor() override;
+
   MemoryGroup CodeMem;
   MemoryGroup RWDataMem;
   MemoryGroup RODataMem;
Index: include/llvm/Support/MemoryBuffer.h
===================================================================
--- include/llvm/Support/MemoryBuffer.h
+++ include/llvm/Support/MemoryBuffer.h
@@ -148,6 +148,9 @@
   virtual BufferKind getBufferKind() const = 0;
 
   MemoryBufferRef getMemBufferRef() const;
+
+private:
+  virtual void anchor();
 };
 
 /// This class is an extension of MemoryBuffer, which allows copy-on-write
Index: include/llvm/Support/raw_ostream.h
===================================================================
--- include/llvm/Support/raw_ostream.h
+++ include/llvm/Support/raw_ostream.h
@@ -329,6 +329,8 @@
   /// Copy data into the buffer. Size must not be greater than the number of
   /// unused bytes in the buffer.
   void copy_to_buffer(const char *Ptr, size_t Size);
+
+  virtual void anchor();
 };
 
 /// An abstract base class for streams implementations that also support a
@@ -336,6 +338,7 @@
 /// but needs to patch in a header that needs to know the output size.
 class raw_pwrite_stream : public raw_ostream {
   virtual void pwrite_impl(const char *Ptr, size_t Size, uint64_t Offset) = 0;
+  void anchor() override;
 
 public:
   explicit raw_pwrite_stream(bool Unbuffered = false)
@@ -383,6 +386,8 @@
   /// Set the flag indicating that an output error has been encountered.
   void error_detected(std::error_code EC) { this->EC = EC; }
 
+  void anchor() override;
+
 public:
   /// Open the specified file for writing. If an error occurs, information
   /// about the error is put into EC, and the stream should be immediately
Index: lib/ExecutionEngine/MCJIT/MCJIT.h
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.h
+++ lib/ExecutionEngine/MCJIT/MCJIT.h
@@ -42,6 +42,7 @@
 private:
   MCJIT &ParentEngine;
   std::shared_ptr<LegacyJITSymbolResolver> ClientResolver;
+  void anchor() override;
 };
 
 // About Module states: added->loaded->finalized.
Index: lib/ExecutionEngine/MCJIT/MCJIT.cpp
===================================================================
--- lib/ExecutionEngine/MCJIT/MCJIT.cpp
+++ lib/ExecutionEngine/MCJIT/MCJIT.cpp
@@ -665,3 +665,5 @@
     return nullptr;
   return ClientResolver->findSymbol(Name);
 }
+
+void LinkingSymbolResolver::anchor() {}
Index: lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
===================================================================
--- lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
+++ lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
@@ -298,4 +298,6 @@
   return (void*)Addr;
 }
 
+void RTDyldMemoryManager::anchor() {}
+void MCJITMemoryManager::anchor() {}
 } // namespace llvm
Index: lib/ExecutionEngine/SectionMemoryManager.cpp
===================================================================
--- lib/ExecutionEngine/SectionMemoryManager.cpp
+++ lib/ExecutionEngine/SectionMemoryManager.cpp
@@ -232,6 +232,8 @@
 
 SectionMemoryManager::MemoryMapper::~MemoryMapper() {}
 
+void SectionMemoryManager::anchor() {}
+
 namespace {
 // Trivial implementation of SectionMemoryManager::MemoryMapper that just calls
 // into sys::Memory.
Index: lib/Support/MemoryBuffer.cpp
===================================================================
--- lib/Support/MemoryBuffer.cpp
+++ lib/Support/MemoryBuffer.cpp
@@ -531,3 +531,5 @@
   StringRef Identifier = getBufferIdentifier();
   return MemoryBufferRef(Data, Identifier);
 }
+
+void MemoryBuffer::anchor() {}
Index: lib/Support/raw_ostream.cpp
===================================================================
--- lib/Support/raw_ostream.cpp
+++ lib/Support/raw_ostream.cpp
@@ -474,6 +474,8 @@
   return *this;
 }
 
+void raw_ostream::anchor() {}
+
 //===----------------------------------------------------------------------===//
 //  Formatted Output
 //===----------------------------------------------------------------------===//
@@ -727,6 +729,8 @@
   return sys::Process::FileDescriptorHasColors(FD);
 }
 
+void raw_fd_ostream::anchor() {}
+
 //===----------------------------------------------------------------------===//
 //  outs(), errs(), nulls()
 //===----------------------------------------------------------------------===//
@@ -804,3 +808,5 @@
 
 void raw_null_ostream::pwrite_impl(const char *Ptr, size_t Size,
                                    uint64_t Offset) {}
+
+void raw_pwrite_stream::anchor() {}