Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
@@ -17,11 +17,16 @@
 
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
 #include "llvm/BinaryFormat/Wasm.h"
+#include "llvm/CodeGen/MIRYamlMapping.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/MC/MCSymbolWasm.h"
 
 namespace llvm {
 
+namespace yaml {
+struct WebAssemblyFunctionInfo;
+}
+
 /// This class is derived from MachineFunctionInfo and contains private
 /// WebAssembly-specific information for each MachineFunction.
 class WebAssemblyFunctionInfo final : public MachineFunctionInfo {
@@ -54,6 +59,7 @@
 public:
   explicit WebAssemblyFunctionInfo(MachineFunction &MF) : MF(MF) {}
   ~WebAssemblyFunctionInfo() override;
+  void initializeBaseYamlFields(const yaml::WebAssemblyFunctionInfo &YamlMFI);
 
   void addParam(MVT VT) { Params.push_back(VT); }
   const std::vector<MVT> &getParams() const { return Params; }
@@ -135,6 +141,22 @@
 signatureFromMVTs(const SmallVectorImpl<MVT> &Results,
                   const SmallVectorImpl<MVT> &Params);
 
+namespace yaml {
+
+struct WebAssemblyFunctionInfo final : public yaml::MachineFunctionInfo {
+  WebAssemblyFunctionInfo() = default;
+  WebAssemblyFunctionInfo(const llvm::WebAssemblyFunctionInfo &MFI);
+
+  void mappingImpl(yaml::IO &YamlIO) override;
+  ~WebAssemblyFunctionInfo() = default;
+};
+
+template <> struct MappingTraits<WebAssemblyFunctionInfo> {
+  static void mapping(IO &YamlIO, WebAssemblyFunctionInfo &MFI) {}
+};
+
+} // end namespace yaml
+
 } // end namespace llvm
 
 #endif
Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.cpp
@@ -77,3 +77,13 @@
   valTypesFromMVTs(Params, Sig->Params);
   return Sig;
 }
+
+yaml::WebAssemblyFunctionInfo::WebAssemblyFunctionInfo(
+    const llvm::WebAssemblyFunctionInfo &MFI) {}
+
+void yaml::WebAssemblyFunctionInfo::mappingImpl(yaml::IO &YamlIO) {
+  MappingTraits<WebAssemblyFunctionInfo>::mapping(YamlIO, *this);
+}
+
+void WebAssemblyFunctionInfo::initializeBaseYamlFields(
+    const yaml::WebAssemblyFunctionInfo &YamlMFI) {}
Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.h
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.h
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.h
@@ -51,6 +51,14 @@
   TargetTransformInfo getTargetTransformInfo(const Function &F) override;
 
   bool usesPhysRegsForPEI() const override { return false; }
+
+  yaml::MachineFunctionInfo *createDefaultFuncInfoYAML() const override;
+  yaml::MachineFunctionInfo *
+  convertFuncInfoToYAML(const MachineFunction &MF) const override;
+  bool parseMachineFunctionInfo(const yaml::MachineFunctionInfo &,
+                                PerFunctionMIParsingState &PFS,
+                                SMDiagnostic &Error,
+                                SMRange &SourceRange) const override;
 };
 
 } // end namespace llvm
Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -14,8 +14,10 @@
 #include "WebAssemblyTargetMachine.h"
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
 #include "WebAssembly.h"
+#include "WebAssemblyMachineFunctionInfo.h"
 #include "WebAssemblyTargetObjectFile.h"
 #include "WebAssemblyTargetTransformInfo.h"
+#include "llvm/CodeGen/MIRParser/MIParser.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/RegAllocRegistry.h"
@@ -367,3 +369,24 @@
   // Create a mapping from LLVM CodeGen virtual registers to wasm registers.
   addPass(createWebAssemblyRegNumbering());
 }
+
+yaml::MachineFunctionInfo *
+WebAssemblyTargetMachine::createDefaultFuncInfoYAML() const {
+  return new yaml::WebAssemblyFunctionInfo();
+}
+
+yaml::MachineFunctionInfo *WebAssemblyTargetMachine::convertFuncInfoToYAML(
+    const MachineFunction &MF) const {
+  const auto *MFI = MF.getInfo<WebAssemblyFunctionInfo>();
+  return new yaml::WebAssemblyFunctionInfo(*MFI);
+}
+
+bool WebAssemblyTargetMachine::parseMachineFunctionInfo(
+    const yaml::MachineFunctionInfo &MFI, PerFunctionMIParsingState &PFS,
+    SMDiagnostic &Error, SMRange &SourceRange) const {
+  const auto &YamlMFI =
+      reinterpret_cast<const yaml::WebAssemblyFunctionInfo &>(MFI);
+  MachineFunction &MF = PFS.MF;
+  MF.getInfo<WebAssemblyFunctionInfo>()->initializeBaseYamlFields(YamlMFI);
+  return false;
+}
Index: llvm/trunk/test/CodeGen/WebAssembly/function-info.mir
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/function-info.mir
+++ llvm/trunk/test/CodeGen/WebAssembly/function-info.mir
@@ -0,0 +1,11 @@
+# RUN: llc -mtriple=wasm32-unknown-unknown -run-pass wasm-cfg-stackify %s -o - | FileCheck %s
+
+# CHECK-LABEL: function_property_test
+# CHECK: machineFunctionInfo: {}
+name: function_property_test
+liveins:
+  - { reg: '$arguments' }
+body: |
+  bb.0:
+    RETURN_VOID implicit-def dead $arguments
+...