1 files changed, 11 insertions, 46 deletions

diff --git a/include/ruby/internal/core/robject.h b/include/ruby/internal/core/robject.h
index f2028063a6..c2bcae6306 100644
--- a/include/ruby/internal/core/robject.h
+++ b/include/ruby/internal/core/robject.h
@@ -37,16 +37,15 @@
 /**
  * Convenient casting macro.
  *
- * @param   obj  An object, which is in fact an ::RRegexp.
- * @return  The passed object casted to ::RRegexp.
+ * @param   obj  An object, which is in fact an ::RObject.
+ * @return  The passed object casted to ::RObject.
  */
 #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_NUMIV         ROBJECT_NUMIV
+#define ROBJECT_IV_CAPACITY   ROBJECT_IV_CAPACITY
 #define ROBJECT_IVPTR         ROBJECT_IVPTR
-#define ROBJECT_IV_INDEX_TBL  ROBJECT_IV_INDEX_TBL
 /** @endcond */
 
 /**
@@ -75,15 +74,6 @@ enum ruby_robject_flags {
     ROBJECT_EMBED = RUBY_FL_USER1
 };
 
-/**
- * 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)
-};
-
 struct st_table;
 
 /**
@@ -103,13 +93,6 @@ struct RObject {
          * this pattern.
          */
         struct {
-
-            /**
-             * Number of instance variables.  This is per object; objects might
-             * differ in this field even if they have the identical classes.
-             */
-            uint32_t numiv;
-
             /** Pointer to a C array that holds instance variables. */
             VALUE *ivptr;
 
@@ -121,42 +104,24 @@ struct RObject {
              *
              * This is a shortcut for `RCLASS_IV_INDEX_TBL(rb_obj_class(obj))`.
              */
-            struct st_table *iv_index_tbl;
+            struct rb_id_table *iv_index_tbl;
         } heap;
 
-        /**
-         * Embedded instance  variables.  When  an object  is small  enough, it
+        /* Embedded instance variables. When an object is small enough, it
          * uses this area to store the instance variables.
+         *
+         * This is a length 1 array because:
+         *   1. GCC has a bug that does not optimize C flexible array members
+         *      (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102452)
+         *   2. Zero length arrays are not supported by all compilers
          */
-        VALUE ary[ROBJECT_EMBED_LEN_MAX];
+        VALUE ary[1];
     } as;
 };
 
 RBIMPL_ATTR_PURE_UNLESS_DEBUG()
 RBIMPL_ATTR_ARTIFICIAL()
 /**
- * Queries the number of instance variables.
- *
- * @param[in]  obj  Object in question.
- * @return     Its number of instance variables.
- * @pre        `obj` must be an instance of ::RObject.
- */
-static inline uint32_t
-ROBJECT_NUMIV(VALUE obj)
-{
-    RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT);
-
-    if (RB_FL_ANY_RAW(obj, ROBJECT_EMBED)) {
-        return ROBJECT_EMBED_LEN_MAX;
-    }
-    else {
-        return ROBJECT(obj)->as.heap.numiv;
-    }
-}
-
-RBIMPL_ATTR_PURE_UNLESS_DEBUG()
-RBIMPL_ATTR_ARTIFICIAL()
-/**
  * Queries the instance variables.
  *
  * @param[in]  obj  Object in question.