Index: lib/MC/MCParser/AsmParser.cpp
===================================================================
--- lib/MC/MCParser/AsmParser.cpp
+++ lib/MC/MCParser/AsmParser.cpp
@@ -699,7 +699,11 @@
     PlatformParser.reset(createELFAsmParser());
     break;
   case MCObjectFileInfo::IsWasm:
-    llvm_unreachable("Wasm parsing not supported yet");
+    // TODO: WASM will need its own MCAsmParserExtension implementation, but
+    // for now we can re-use the ELF one, since the directives can be the
+    // same for now, and this makes the -triple=wasm32-unknown-unknown-wasm
+    // path work.
+    PlatformParser.reset(createELFAsmParser());
     break;
   }
 
@@ -1313,7 +1317,7 @@
 /// the End argument will be filled with the last location pointed to the '>'
 /// character.
 
-/// There is a gap between the AltMacro's documentation and the single quote implementation. 
+/// There is a gap between the AltMacro's documentation and the single quote implementation.
 /// GCC does not fully support this feature and so we will not support it.
 /// TODO: Adding single quote as a string.
 bool AsmParser::isAltmacroString(SMLoc &StrLoc, SMLoc &EndLoc) {
@@ -2224,7 +2228,7 @@
 }
 
 // Parse and erase curly braces marking block start/end
-bool 
+bool
 AsmParser::parseCurlyBlockScope(SmallVectorImpl<AsmRewrite> &AsmStrRewrites) {
   // Identify curly brace marking block start/end
   if (Lexer.isNot(AsmToken::LCurly) && Lexer.isNot(AsmToken::RCurly))
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
@@ -61,10 +61,62 @@
 }
 
 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 exactly 4 bytes of data.
+  if (Bytes.size() < 4) {
+    Size = 0;
+    return MCDisassembler::Fail;
+  }
+
+  // Encoded as a small-endian 32-bit word in the stream.
+  uint32_t Insn =
+      (Bytes[3] << 24) | (Bytes[2] << 16) | (Bytes[1] << 8) | (Bytes[0] << 0);
+
+  // Calling the auto-generated decoder function.
+  DecodeStatus Result =
+      decodeInstruction(DecoderTableWebAssembly32, MI, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
+  }
+
+  struct DecodeTable {
+    const uint8_t *P;
+    bool DecodePred;
+  };
+
+  const DecodeTable Tables[] = {
+      {DecoderTableVFP32, false},      {DecoderTableVFPV832, false},
+      {DecoderTableNEONData32, true},  {DecoderTableNEONLoadStore32, true},
+      {DecoderTableNEONDup32, true},   {DecoderTablev8NEON32, false},
+      {DecoderTablev8Crypto32, false},
+  };
+
+  for (auto Table : Tables) {
+    Result = decodeInstruction(Table.P, MI, Insn, Address, this, STI);
+    if (Result != MCDisassembler::Fail) {
+      Size = 4;
+      // Add a fake predicate operand, because we share these instruction
+      // definitions with Thumb2 where these instructions are predicable.
+      if (Table.DecodePred && !DecodePredicateOperand(MI, 0xE, Address, this))
+        return MCDisassembler::Fail;
+      return Result;
+    }
+  }
+
+  Result =
+      decodeInstruction(DecoderTableCoProc32, MI, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return checkDecodedInstruction(MI, Size, Address, OS, CS, Insn, Result);
+  }
+
+  Size = 4;
   return MCDisassembler::Fail;
 }
+
+#include "WebAssemblyGenDisassemblerTables.inc"
Index: test/MC/WebAssembly/basic-assembly.s
===================================================================
--- test/MC/WebAssembly/basic-assembly.s
+++ test/MC/WebAssembly/basic-assembly.s
@@ -1,4 +1,5 @@
 # RUN: llvm-mc -triple=wasm32-unknown-unknown-elf < %s | FileCheck %s
+# RUN: llvm-mc -triple=wasm32-unknown-unknown-wasm < %s | FileCheck %s
 
     .text
     .type    test0,@function