Store information about builtins in descriptors

src/builtins/builtins.h

Index: src/builtins/builtins.h
diff --git a/src/builtins/builtins.h b/src/builtins/builtins.h
index 10d6f21705b3c99e1f8e039d0cd5722d08192449..0be09e429ef1fd4d159837e230524986371436c7 100644
--- a/src/builtins/builtins.h
+++ b/src/builtins/builtins.h
@@ -569,13 +569,29 @@ class Builtins {
 #define DEF_ENUM(Name, ...) k##Name,
     BUILTIN_LIST_ALL(DEF_ENUM)
 #undef DEF_ENUM
-        builtin_count
+        BUILTIN_COUNT
   };
 
 #define DECLARE_BUILTIN_ACCESSOR(Name, ...) Handle<Code> Name();
   BUILTIN_LIST_ALL(DECLARE_BUILTIN_ACCESSOR)
 #undef DECLARE_BUILTIN_ACCESSOR
 
+  enum Kind { CPP, API, TFJ, TFS, ASM, ASH, DBG };
+
+  struct Descriptor {
+    Name id;
+    Kind kind;
+
+    // For CPP and API functions, this is the C++ entry point.
+    Address entry;
+
+    // Note: These are always Code objects, but to conform with
+    // IterateBuiltins(), we use an Object* here.
+    Object* code;
+
+    const char* debug_name;
+  };
+
   // Convenience wrappers.
   Handle<Code> CallFunction(
       ConvertReceiverMode = ConvertReceiverMode::kAny,
@@ -593,11 +609,11 @@ class Builtins {
   Code* builtin(Name name) {
     // Code::cast cannot be used here since we access builtins
     // during the marking phase of mark sweep. See IC::Clear.
-    return reinterpret_cast<Code*>(builtins_[name]);
+    return reinterpret_cast<Code*>(builtins_[name].code);
   }
 
   Address builtin_address(Name name) {
-    return reinterpret_cast<Address>(&builtins_[name]);
+    return reinterpret_cast<Address>(&builtins_[name].code);
   }
 
   const char* name(int index);
@@ -651,10 +667,7 @@ class Builtins {
 #undef DECLARE_ASM
 #undef DECLARE_TF
 
-  // Note: These are always Code objects, but to conform with
-  // IterateBuiltins() above which assumes Object**'s for the callback
-  // function f, we use an Object* array here.
-  Object* builtins_[builtin_count];
+  Descriptor builtins_[BUILTIN_COUNT];
   bool initialized_;
 
   friend class Isolate;