[wasm] Differentiate unnamed and empty names

src/js/messages.js

Index: src/js/messages.js
diff --git a/src/js/messages.js b/src/js/messages.js
index 2ff2dd052baaad0256d9a71d6a82c0d811548a66..28e7e426cb9c192d0328d366bfbed0a1237eae3f 100644
--- a/src/js/messages.js
+++ b/src/js/messages.js
@@ -633,7 +633,6 @@ function CallSiteGetFunctionName() {
   if (HAS_PRIVATE(this, callSiteWasmObjectSymbol)) {
     var wasm = GET_PRIVATE(this, callSiteWasmObjectSymbol);
     var func_index = GET_PRIVATE(this, callSiteWasmFunctionIndexSymbol);
-    if (IS_UNDEFINED(wasm)) return "<WASM>";
     return %WasmGetFunctionName(wasm, func_index);
   }
   return %CallSiteGetFunctionNameRT(this);
@@ -679,6 +678,8 @@ function CallSiteToString() {
     var funName = this.getFunctionName();
     var funcIndex = GET_PRIVATE(this, callSiteWasmFunctionIndexSymbol);
     var pos = this.getPosition();
+    if (IS_NULL_OR_UNDEFINED(funName))
+      funName = "<WASM UNNAMED>";

[titzer, 2016/05/12 09:05:51]

Should probably also add the position here.

[Clemens Hammacher, 2016/05/12 09:45:57]

It's still added in the line below, there is no return here.

[titzer, 2016/05/12 09:54:35]

Acknowledged.

     return funName + " (<WASM>:" + funcIndex + ":" + pos + ")";

[titzer, 2016/05/12 09:05:51]

bikeshed: for this line: 
" (<WASM>[" + funcIndex +"]+" + pos + ")"

[Clemens Hammacher, 2016/05/12 09:45:57]

Would you prefer this format for all wasm frames? For the simple stack traces,
we currently also output "<WASM>:funcIndex:pos".

[titzer, 2016/05/12 09:54:35]

yes

   }