Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp
@@ -90,11 +90,13 @@
   }
   for (const auto &G : M.globals()) {
     if (!G.hasInitializer() && G.hasExternalLinkage()) {
-      uint16_t Size = M.getDataLayout().getTypeAllocSize(G.getValueType());
-      if (TM.getTargetTriple().isOSBinFormatELF())
-        getTargetStreamer()->emitGlobalImport(G.getGlobalIdentifier());
-      OutStreamer->emitELFSize(getSymbol(&G),
-                               MCConstantExpr::create(Size, OutContext));
+      if (G.getValueType()->isSized()) {
+        uint16_t Size = M.getDataLayout().getTypeAllocSize(G.getValueType());
+        if (TM.getTargetTriple().isOSBinFormatELF())
+          getTargetStreamer()->emitGlobalImport(G.getGlobalIdentifier());
+        OutStreamer->emitELFSize(getSymbol(&G),
+                                 MCConstantExpr::create(Size, OutContext));
+      }
     }
   }
 }
Index: llvm/trunk/test/CodeGen/WebAssembly/global.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/global.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/global.ll
@@ -213,3 +213,10 @@
 ; CHECK-NEXT: .size       pointer_to_array, 4
 @array = internal constant [8 x i8] zeroinitializer, align 1
 @pointer_to_array = constant i8* getelementptr inbounds ([8 x i8], [8 x i8]* @array, i32 0, i32 4), align 4
+
+; Handle external objects with opaque type.
+%struct.ASTRUCT = type opaque
+@g_struct = external global %struct.ASTRUCT, align 1
+define i32 @address_of_opaque()  {
+  ret i32 ptrtoint (%struct.ASTRUCT* @g_struct to i32)
+}