1 files changed, 16 insertions, 50 deletions

diff --git a/include/ruby/internal/core/robject.h b/include/ruby/internal/core/robject.h
index b1c2e1b0a9..99f6470ac1 100644
--- a/include/ruby/internal/core/robject.h
+++ b/include/ruby/internal/core/robject.h
@@ -42,10 +42,10 @@
  */
 #define ROBJECT(obj)          RBIMPL_CAST((struct RObject *)(obj))
 /** @cond INTERNAL_MACRO */
-#define ROBJECT_EMBED_LEN_MAX ROBJECT_EMBED_LEN_MAX
-#define ROBJECT_EMBED         ROBJECT_EMBED
-#define ROBJECT_IV_CAPACITY   ROBJECT_IV_CAPACITY
-#define ROBJECT_IVPTR         ROBJECT_IVPTR
+#define ROBJECT_EMBED_LEN_MAX       ROBJECT_EMBED_LEN_MAX
+#define ROBJECT_HEAP                ROBJECT_HEAP
+#define ROBJECT_FIELDS_CAPACITY     ROBJECT_FIELDS_CAPACITY
+#define ROBJECT_FIELDS              ROBJECT_FIELDS
 /** @endcond */
 
 /**
@@ -55,10 +55,12 @@
  */
 enum ruby_robject_flags {
     /**
-     * This flag has  something to do with memory footprint.   If the object is
-     * "small"  enough, ruby  tries to  be creative  to abuse  padding bits  of
-     * struct ::RObject for storing instance variables.  This flag denotes that
-     * situation.
+     * This flag marks that the object's instance variables are stored in an
+     * external heap buffer.
+     * Normally, instance variable references are stored inside the object slot,
+     * but if it overflow, Ruby may have to allocate a separate buffer and spills
+     * the instance variables there.
+     * This flag denotes that situation.
      *
      * @warning  This  bit has  to be  considered read-only.   Setting/clearing
      *           this  bit without  corresponding fix  up must  cause immediate
@@ -71,20 +73,9 @@ enum ruby_robject_flags {
      * 3rd parties must  not be aware that  there even is more than  one way to
      * store instance variables.  Might better be hidden.
      */
-    ROBJECT_EMBED = RUBY_FL_USER1
+    ROBJECT_HEAP = RUBY_FL_USER4
 };
 
-#if !USE_RVARGC
-/**
- * This is an enum because GDB wants it (rather than a macro).  People need not
- * bother.
- */
-enum ruby_robject_consts {
-    /** Max possible number of instance variables that can be embedded. */
-    ROBJECT_EMBED_LEN_MAX = RBIMPL_EMBED_LEN_MAX_OF(VALUE)
-};
-#endif
-
 struct st_table;
 
 /**
@@ -105,20 +96,9 @@ struct RObject {
          */
         struct {
             /** Pointer to a C array that holds instance variables. */
-            VALUE *ivptr;
-
-            /**
-             * This  is a  table that  holds  instance variable  name to  index
-             * mapping.  Used when accessing instance variables using names.
-             *
-             * @internal
-             *
-             * This is a shortcut for `RCLASS_IV_INDEX_TBL(rb_obj_class(obj))`.
-             */
-            struct rb_id_table *iv_index_tbl;
+            VALUE *fields;
         } heap;
 
-#if USE_RVARGC
         /* Embedded instance variables. When an object is small enough, it
          * uses this area to store the instance variables.
          *
@@ -128,23 +108,9 @@ struct RObject {
          *   2. Zero length arrays are not supported by all compilers
          */
         VALUE ary[1];
-#else
-        /**
-        * Embedded instance  variables.  When  an object  is small  enough, it
-        * uses this area to store the instance variables.
-        */
-        VALUE ary[ROBJECT_EMBED_LEN_MAX];
-#endif
     } as;
 };
 
-/* Offsets for YJIT */
-#ifndef __cplusplus
-static const int32_t ROBJECT_OFFSET_AS_HEAP_IVPTR = offsetof(struct RObject, as.heap.ivptr);
-static const int32_t ROBJECT_OFFSET_AS_HEAP_IV_INDEX_TBL = offsetof(struct RObject, as.heap.iv_index_tbl);
-static const int32_t ROBJECT_OFFSET_AS_ARY = offsetof(struct RObject, as.ary);
-#endif
-
 RBIMPL_ATTR_PURE_UNLESS_DEBUG()
 RBIMPL_ATTR_ARTIFICIAL()
 /**
@@ -159,17 +125,17 @@ RBIMPL_ATTR_ARTIFICIAL()
  * @shyouhei finds no reason for this to be visible from extension libraries.
  */
 static inline VALUE *
-ROBJECT_IVPTR(VALUE obj)
+ROBJECT_FIELDS(VALUE obj)
 {
     RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
 
     struct RObject *const ptr = ROBJECT(obj);
 
-    if (RB_FL_ANY_RAW(obj, ROBJECT_EMBED)) {
-        return ptr->as.ary;
+    if (RB_UNLIKELY(RB_FL_ANY_RAW(obj, ROBJECT_HEAP))) {
+        return ptr->as.heap.fields;
     }
     else {
-        return ptr->as.heap.ivptr;
+        return ptr->as.ary;
     }
 }