Make global eval faster by lazily computing its call position.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index a2ff1ecde645e68da95807872fa3f578243df26b..e764c272a4bdc6d5a5b2f0a91a0e7cc57fad03e6 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -6436,8 +6436,9 @@ class Script: public Struct {
   // function from which eval was called.
   DECL_ACCESSORS(eval_from_shared, Object)
 
-  // [eval_from_position]: the source position in the code for the
-  // function from which eval was called.
+  // [eval_from_position]: the source position in the code for the function
+  // from which eval was called, as positive integer. Or the code offset in the
+  // code from which eval was called, as negative integer.
   DECL_INT_ACCESSORS(eval_from_position)
 
   // [shared_function_infos]: weak fixed array containing all shared
@@ -6490,6 +6491,13 @@ class Script: public Struct {
 
   static Handle<Object> GetNameOrSourceURL(Handle<Script> script);
 
+  // Set eval origin for stack trace formatting.
+  static void SetEvalOrigin(Handle<Script> script,
+                            Handle<SharedFunctionInfo> outer,
+                            int eval_position);
+  // Retrieve source position from where eval was called.
+  int GetEvalPosition();
+
   // Init line_ends array with source code positions of line ends.
   static void InitLineEnds(Handle<Script> script);