diff --git a/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp b/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp
index 55346f71c6f..5a54b3a24c8 100644
--- a/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp
+++ b/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCAsmInfo.cpp
@@ -23,13 +23,20 @@ using namespace llvm;
 WebAssemblyMCAsmInfo::~WebAssemblyMCAsmInfo() {}
 
 WebAssemblyMCAsmInfo::WebAssemblyMCAsmInfo(const Triple &T) {
-  PointerSize = CalleeSaveStackSlotSize = T.isArch64Bit();
+  PointerSize = CalleeSaveStackSlotSize = T.isArch64Bit() ? 8 : 4;
 
   // TODO: What should MaxInstLength be?
 
+  // WebAssembly's text format uses s-expressions to represent its AST,
+  // LISP-style comments are therefore suitable.
+  CommentString = ";";
+
   PrivateGlobalPrefix = "";
   PrivateLabelPrefix = "";
 
+  InlineAsmStart = ";APP\n";
+  InlineAsmEnd = ";NO_APP\n";
+
   UseDataRegionDirectives = true;
 
   Data8bitsDirective = "\t.int8\t";