Teach Scopes whether they will end up being lazily compiled or not

src/ast/scopes.h

Index: src/ast/scopes.h
diff --git a/src/ast/scopes.h b/src/ast/scopes.h
index ec946142e8d3c17637ff615efcc7fbee959cb8f8..45e8346d5c6a983ec1f504d61fc33d08fe315a5b 100644
--- a/src/ast/scopes.h
+++ b/src/ast/scopes.h
@@ -418,6 +418,13 @@ class Scope: public ZoneObject {
   bool is_debug_evaluate_scope() const { return is_debug_evaluate_scope_; }
 
   bool is_lazily_parsed() const { return is_lazily_parsed_; }
+  bool should_compile_lazily() const {
+    return is_lazily_parsed_ || should_compile_lazily_;
+  }
+
+  // Marks this scope and all inner scopes (except for inner function scopes)
+  // as lazy.

[marja, 2016/10/06 11:53:06]

Why "except for inner function scopes"?

If we compile a function lazily, don't we always compile its inner functions
lazily too?

(Also, in the comment, it's not clear what "lazy" means, I think we should be
clear with the terminology... it can mean either "lazily parsed" or "lazily
compiled" or "something that was previously lazily parsed" or "something we
happen to reparse for some other reason".)

[jochen (gone - plz use gerrit), 2016/10/06 15:05:04]

yeah, but not the other way round... if we compile it eagerly, we don't
necessarily compile inner functions lazily (but all inner scopes of the current
function)

+  void SetShouldCompileLazily(bool is_lazy);
 
  protected:
   explicit Scope(Zone* zone);
@@ -447,7 +454,7 @@ class Scope: public ZoneObject {
     DCHECK(!already_resolved_);
     // A lazily parsed scope doesn't contain enough information to create a
     // ScopeInfo from it.
-    if (is_lazily_parsed_) return false;
+    if (should_compile_lazily()) return false;
     // The debugger expects all functions to have scope infos.
     // TODO(jochen|yangguo): Remove this requirement.
     if (is_function_scope()) return true;
@@ -523,6 +530,7 @@ class Scope: public ZoneObject {
   bool is_declaration_scope_ : 1;
 
   bool is_lazily_parsed_ : 1;
+  bool should_compile_lazily_ : 1;
 
   // Create a non-local variable with a given name.
   // These variables are looked up dynamically at runtime.