Collect type information based on stack allocated values for OSR.

src/typing.h

Index: src/typing.h
diff --git a/src/typing.h b/src/typing.h
index a111ae5fd1594d14868ba2db80df27a34e2caf1e..ec9132f161e9bbf808ab99e675bef7258f3ef3f2 100644
--- a/src/typing.h
+++ b/src/typing.h
@@ -58,6 +58,9 @@ class AstTyper: public AstVisitor {
  private:
   explicit AstTyper(CompilationInfo* info);
 
+  Effect ObservedOnStack(Object* value);
+  void ObserveTypesAtOsrEntry(IterationStatement* stmt);
+
   static const int kNoVar = INT_MIN;
   typedef v8::internal::Effects<int, kNoVar> Effects;
   typedef v8::internal::NestedEffects<int, kNoVar> Store;
@@ -82,12 +85,15 @@ class AstTyper: public AstVisitor {
   }
   void ExitEffects() { store_ = store_.Pop(); }
 
+  int parameter_index(int index) { return -index - 2; }
+  int stack_local_index(int index) { return index; }
+
   int variable_index(Variable* var) {
     // Stack locals have the range [0 .. l]
     // Parameters have the range [-1 .. p]
     // We map this to [-p-2 .. -1, 0 .. l]
-    return var->IsStackLocal() ? var->index() :
-           var->IsParameter() ? -var->index() - 2 : kNoVar;
+    return var->IsStackLocal() ? stack_local_index(var->index()) :
+           var->IsParameter() ? parameter_index(var->index()) : kNoVar;
   }
 
   void VisitDeclarations(ZoneList<Declaration*>* declarations);