[interpreter] Fix stack trace printers for debugging.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index c81afcc0e744226b626a9ba497af6199aa6ec5ef..d6ac75d3fe16f08faec41afd895e93c5270eaf19 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -1327,9 +1327,17 @@ void Isolate::PrintCurrentStackTrace(FILE* out) {
     HandleScope scope(this);
     // Find code position if recorded in relocation info.
     StandardFrame* frame = it.frame();
-    Code* code = frame->LookupCode();
-    int offset = static_cast<int>(frame->pc() - code->instruction_start());
-    int pos = frame->LookupCode()->SourcePosition(offset);
+    int pos;
+    if (frame->is_java_script() &&

[Michael Starzinger, 2016/04/21 17:05:18]

nit: Just "frame->is_interpreted()" is sufficient. No need to cast.

[Yang, 2016/04/22 05:03:39]

Done.

+        JavaScriptFrame::cast(frame)->is_interpreted()) {
+      InterpretedFrame* iframe = reinterpret_cast<InterpretedFrame*>(frame);
+      pos = iframe->GetBytecodeArray()->SourcePosition(
+          iframe->GetBytecodeOffset());
+    } else {
+      Code* code = frame->LookupCode();
+      int offset = static_cast<int>(frame->pc() - code->instruction_start());
+      pos = frame->LookupCode()->SourcePosition(offset);
+    }
     Handle<Object> pos_obj(Smi::FromInt(pos), this);
     // Fetch function and receiver.
     Handle<JSFunction> fun(frame->function());