Index: lib/Target/WebAssembly/CMakeLists.txt
===================================================================
--- lib/Target/WebAssembly/CMakeLists.txt
+++ lib/Target/WebAssembly/CMakeLists.txt
@@ -3,6 +3,7 @@
 tablegen(LLVM WebAssemblyGenAsmMatcher.inc -gen-asm-matcher)
 tablegen(LLVM WebAssemblyGenAsmWriter.inc -gen-asm-writer)
 tablegen(LLVM WebAssemblyGenDAGISel.inc -gen-dag-isel)
+tablegen(LLVM WebAssemblyGenDisassemblerTables.inc -gen-disassembler)
 tablegen(LLVM WebAssemblyGenFastISel.inc -gen-fast-isel)
 tablegen(LLVM WebAssemblyGenInstrInfo.inc -gen-instr-info)
 tablegen(LLVM WebAssemblyGenMCCodeEmitter.inc -gen-emitter)
Index: lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
===================================================================
--- lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
+++ lib/Target/WebAssembly/Disassembler/WebAssemblyDisassembler.cpp
@@ -19,16 +19,22 @@
 #include "WebAssembly.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
+#include "llvm/MC/MCFixedLenDisassembler.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/TargetRegistry.h"
+
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm-disassembler"
 
+using DecodeStatus = MCDisassembler::DecodeStatus;
+
+#include "WebAssemblyGenDisassemblerTables.inc"
+
 namespace {
 class WebAssemblyDisassembler final : public MCDisassembler {
   std::unique_ptr<const MCInstrInfo> MCII;
@@ -61,10 +67,23 @@
 }
 
 MCDisassembler::DecodeStatus WebAssemblyDisassembler::getInstruction(
-    MCInst &MI, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t /*Address*/,
+    MCInst &MI, uint64_t &Size, ArrayRef<uint8_t> Bytes, uint64_t Address,
     raw_ostream &OS, raw_ostream &CS) const {
-
-  // TODO: Implement disassembly.
+  CommentStream = &CS;
+  // We want to read at least 1 byte of data.
+  if (Bytes.size() < 1) {
+    Size = 0;
+    return MCDisassembler::Fail;
+  }
+  uint32_t Insn = Bytes[0];
+  Size = 1;  // FIXME
+  // Calling the auto-generated decoder function.
+  DecodeStatus Result =
+      decodeInstruction(DecoderTable8, MI, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
+  }
 
   return MCDisassembler::Fail;
 }
+
Index: lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
===================================================================
--- lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
+++ lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.h
@@ -37,14 +37,18 @@
                  const MCSubtargetInfo &STI) override;
 
   // Used by tblegen code.
-  void printOperand(const MCInst *MI, unsigned OpNo, raw_ostream &O);
+  void printOperand(const MCInst *MI, unsigned OpNo, const MCSubtargetInfo &STI,
+                    raw_ostream &O);
   void printWebAssemblyP2AlignOperand(const MCInst *MI, unsigned OpNo,
+                                      const MCSubtargetInfo &STI,
                                       raw_ostream &O);
   void printWebAssemblySignatureOperand(const MCInst *MI, unsigned OpNo,
+                                        const MCSubtargetInfo &STI,
                                         raw_ostream &O);
 
   // Autogenerated by tblgen.
-  void printInstruction(const MCInst *MI, raw_ostream &O);
+  void printInstruction(const MCInst *MI, const MCSubtargetInfo &STI,
+                        raw_ostream &O);
   static const char *getRegisterName(unsigned RegNo);
 };
 
Index: lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
===================================================================
--- lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
+++ lib/Target/WebAssembly/InstPrinter/WebAssemblyInstPrinter.cpp
@@ -46,9 +46,9 @@
 
 void WebAssemblyInstPrinter::printInst(const MCInst *MI, raw_ostream &OS,
                                        StringRef Annot,
-                                       const MCSubtargetInfo & /*STI*/) {
+                                       const MCSubtargetInfo &STI) {
   // Print the instruction (this uses the AsmStrings from the .td files).
-  printInstruction(MI, OS);
+  printInstruction(MI, STI, OS);
 
   // Print any additional variadic operands.
   const MCInstrDesc &Desc = MII.get(MI->getOpcode());
@@ -61,7 +61,7 @@
           (MI->getOpcode() != WebAssembly::CALL_INDIRECT_VOID ||
            i != Desc.getNumOperands()))
         OS << ", ";
-      printOperand(MI, i, OS);
+      printOperand(MI, i, STI, OS);
     }
 
   // Print any added annotation.
@@ -138,6 +138,7 @@
 }
 
 void WebAssemblyInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,
+                                          const MCSubtargetInfo &/*STI*/,
                                           raw_ostream &O) {
   const MCOperand &Op = MI->getOperand(OpNo);
   if (Op.isReg()) {
@@ -197,6 +198,8 @@
 void
 WebAssemblyInstPrinter::printWebAssemblyP2AlignOperand(const MCInst *MI,
                                                        unsigned OpNo,
+                                                       const MCSubtargetInfo &
+                                                         STI,
                                                        raw_ostream &O) {
   int64_t Imm = MI->getOperand(OpNo).getImm();
   if (Imm == WebAssembly::GetDefaultP2Align(MI->getOpcode()))
@@ -207,6 +210,8 @@
 void
 WebAssemblyInstPrinter::printWebAssemblySignatureOperand(const MCInst *MI,
                                                          unsigned OpNo,
+                                                         const MCSubtargetInfo &
+                                                           STI,
                                                          raw_ostream &O) {
   int64_t Imm = MI->getOperand(OpNo).getImm();
   switch (WebAssembly::ExprType(Imm)) {
Index: lib/Target/WebAssembly/WebAssembly.td
===================================================================
--- lib/Target/WebAssembly/WebAssembly.td
+++ lib/Target/WebAssembly/WebAssembly.td
@@ -82,7 +82,15 @@
   let ShouldEmitMatchRegisterName = 0;
 }
 
+def WebAssemblyAsmWriter : AsmWriter {
+  string AsmWriterClassName  = "InstPrinter";
+  int PassSubtarget = 1;
+  int Variant = 0;
+  bit isMCAsmWriter = 1;
+}
+
 def WebAssembly : Target {
   let InstructionSet = WebAssemblyInstrInfo;
   let AssemblyParsers  = [WebAssemblyAsmParser];
+  let AssemblyWriters = [WebAssemblyAsmWriter];
 }
Index: lib/Target/WebAssembly/WebAssemblyInstrFormats.td
===================================================================
--- lib/Target/WebAssembly/WebAssemblyInstrFormats.td
+++ lib/Target/WebAssembly/WebAssemblyInstrFormats.td
@@ -15,6 +15,8 @@
 // WebAssembly Instruction Format.
 class WebAssemblyInst<bits<32> inst, string asmstr> : Instruction {
   field bits<32> Inst = inst; // Instruction encoding.
+  field bits<32> SoftFail = 0;  // Needed for disassembler?
+  let Size        = 1;  // Needed for disassembler?
   let Namespace   = "WebAssembly";
   let Pattern     = [];
   let AsmString   = asmstr;