A64: Implement LOsrEntry and LUnknownOSRValue

src/a64/lithium-a64.h

Index: src/a64/lithium-a64.h
diff --git a/src/a64/lithium-a64.h b/src/a64/lithium-a64.h
index d040f95a352f2ed80fbb278ba8a12b18c78a5ae5..dae8e40160dab574c9b78426fa5278f8648a5d8e 100644
--- a/src/a64/lithium-a64.h
+++ b/src/a64/lithium-a64.h
@@ -191,6 +191,7 @@ class LCodeGen;
   V(Typeof)                                     \
   V(TypeofIsAndBranch)                          \
   V(Uint32ToDouble)                             \
+  V(UnknownOSRValue)                            \
   V(ValueOf)                                    \
   V(CheckMapValue)                              \
   V(LoadFieldByIndex)                           \
@@ -320,6 +321,13 @@ class LTemplateInstruction: public LInstruction {
 };
 
 
+class LUnknownOSRValue: public LTemplateInstruction<1, 0, 0> {
+ public:
+  virtual bool HasInterestingComment(LCodeGen* gen) const { return false; }
+  DECLARE_CONCRETE_INSTRUCTION(UnknownOSRValue, "unknown-osr-value")
+};
+
+
 template<int I, int T>
 class LControlInstruction: public LTemplateInstruction<0, I, T> {
  public: