Index: include/llvm/ObjectYAML/WasmYAML.h
===================================================================
--- include/llvm/ObjectYAML/WasmYAML.h
+++ include/llvm/ObjectYAML/WasmYAML.h
@@ -108,6 +108,7 @@
 
 struct Section {
   Section(SectionType SecType) : Type(SecType) {}
+  virtual ~Section();
 
   SectionType Type;
   std::vector<Relocation> Relocations;
Index: lib/ObjectYAML/WasmYAML.cpp
===================================================================
--- lib/ObjectYAML/WasmYAML.cpp
+++ lib/ObjectYAML/WasmYAML.cpp
@@ -17,6 +17,15 @@
 #include "llvm/Support/MipsABIFlags.h"
 
 namespace llvm {
+
+namespace WasmYAML {
+
+// Declared here rather than in the header to comply with:
+// http://llvm.org/docs/CodingStandards.html#provide-a-virtual-method-anchor-for-classes-in-headers
+Section::~Section() {}
+
+} // end namespace WasmYAML
+
 namespace yaml {
 
 void MappingTraits<WasmYAML::FileHeader>::mapping(