[interpreter] Add a safety-net for interpreter entry.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index 89e8078c2035f629adc2d70f5661da363461248f..13ef288555ec3e7d8f9239b23031efa6bdfb482c 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -604,10 +604,8 @@ void Builtins::Generate_JSConstructEntryTrampoline(MacroAssembler* masm) {
 //   o rbp: the caller's frame pointer
 //   o rsp: stack pointer (pointing to return address)
 //
-// The function builds a JS frame.  Please see JavaScriptFrameConstants in
-// frames-x64.h for its layout.
-// TODO(rmcilroy): We will need to include the current bytecode pointer in the
-// frame.
+// The function builds an interpreter frame.  See InterpreterFrameConstants in
+// frames.h for its layout.
 void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // MANUAL indicates that the scope shouldn't actually generate code to set up
@@ -705,6 +703,9 @@ void Builtins::Generate_InterpreterEntryTrampoline(MacroAssembler* masm) {
   // and header removal.
   __ addp(rbx, Immediate(Code::kHeaderSize - kHeapObjectTag));
   __ call(rbx);
+
+  // Even though the first bytecode handler was called, we will never return.
+  __ Abort(kUnexpectedReturnFromBytecodeHandler);
 }