[type profile] Collect return types.

src/ast/ast.h

Index: src/ast/ast.h
diff --git a/src/ast/ast.h b/src/ast/ast.h
index 2d9833aee1eb2b8f7aa3b8e3de1acf2fb2967720..de603f8ad3fe2b6199f43e3beca6131cf99d0106 100644
--- a/src/ast/ast.h
+++ b/src/ast/ast.h
@@ -904,6 +904,15 @@ class ReturnStatement final : public JumpStatement {
   Type type() const { return TypeField::decode(bit_field_); }
   bool is_async_return() const { return type() == kAsyncReturn; }
 
+  FeedbackSlot TypeProfileSlot() const {
+    DCHECK(HasTypeProfileSlot());
+    return type_profile_slot_;
+  }
+
+  void SetTypeProfileSlot(FeedbackSlot slot) { type_profile_slot_ = slot; }
+
+  bool HasTypeProfileSlot() const { return !type_profile_slot_.IsInvalid(); }
+
  private:
   friend class AstNodeFactory;
 
@@ -912,6 +921,8 @@ class ReturnStatement final : public JumpStatement {
     bit_field_ |= TypeField::encode(type);
   }
 
+  FeedbackSlot type_profile_slot_;
+
   Expression* expression_;
 
   class TypeField