Revert this until we can figure out WB issues or remove shapes from GC

Revert "* expand tabs. [ci skip]"

This reverts commit 830b5b5c351c5c6efa5ad461ae4ec5085e5f0275.

Revert "This commit implements the Object Shapes technique in CRuby."

This reverts commit 9ddfd2ca004d1952be79cf1b84c52c79a55978f4.

4 files changed, 27 insertions, 12 deletions

diff --git a/internal/class.h b/internal/class.h
index 36635d6eaa..ae680564a6 100644
--- a/internal/class.h
+++ b/internal/class.h
@@ -14,7 +14,6 @@
 #include "ruby/internal/stdbool.h"     /* for bool */
 #include "ruby/intern.h"        /* for rb_alloc_func_t */
 #include "ruby/ruby.h"          /* for struct RBasic */
-#include "shape.h"
 
 #ifdef RCLASS_SUPER
 # undef RCLASS_SUPER
@@ -27,9 +26,9 @@ struct rb_subclass_entry {
 };
 
 struct rb_iv_index_tbl_entry {
-    uint32_t idx;
-    shape_id_t source_shape_id;
-    shape_id_t dest_shape_id;
+    uint32_t index;
+    rb_serial_t class_serial;
+    VALUE class_value;
 };
 
 struct rb_cvar_class_tbl_entry {
@@ -39,6 +38,7 @@ struct rb_cvar_class_tbl_entry {
 };
 
 struct rb_classext_struct {
+    struct st_table *iv_index_tbl; // ID -> struct rb_iv_index_tbl_entry
     struct st_table *iv_tbl;
 #if SIZEOF_SERIAL_T == SIZEOF_VALUE /* otherwise m_tbl is in struct RClass */
     struct rb_id_table *m_tbl;
@@ -64,8 +64,6 @@ struct rb_classext_struct {
     const VALUE refined_class;
     rb_alloc_func_t allocator;
     const VALUE includer;
-    uint32_t max_iv_count;
-    uint16_t shape_id;
 };
 
 struct RClass {
@@ -104,6 +102,7 @@ typedef struct rb_classext_struct rb_classext_t;
 #define RCLASS_CALLABLE_M_TBL(c) (RCLASS_EXT(c)->callable_m_tbl)
 #define RCLASS_CC_TBL(c) (RCLASS_EXT(c)->cc_tbl)
 #define RCLASS_CVC_TBL(c) (RCLASS_EXT(c)->cvc_tbl)
+#define RCLASS_IV_INDEX_TBL(c) (RCLASS_EXT(c)->iv_index_tbl)
 #define RCLASS_ORIGIN(c) (RCLASS_EXT(c)->origin_)
 #define RCLASS_REFINED_CLASS(c) (RCLASS_EXT(c)->refined_class)
 #if SIZEOF_SERIAL_T == SIZEOF_VALUE
diff --git a/internal/imemo.h b/internal/imemo.h
index 20bfff8d7c..91b524e0a6 100644
--- a/internal/imemo.h
+++ b/internal/imemo.h
@@ -45,7 +45,6 @@ enum imemo_type {
     imemo_callinfo       = 11,
     imemo_callcache      = 12,
     imemo_constcache     = 13,
-    imemo_shape          = 14,
 };
 
 /* CREF (Class REFerence) is defined in method.h */
diff --git a/internal/object.h b/internal/object.h
index 7b54e13dd2..88f3a44bc6 100644
--- a/internal/object.h
+++ b/internal/object.h
@@ -9,6 +9,11 @@
  * @brief      Internal header for Object.
  */
 #include "ruby/ruby.h"          /* for VALUE */
+#include "internal/class.h"     /* for RCLASS_IV_INDEX_TBL */
+
+#ifdef ROBJECT_IV_INDEX_TBL
+# undef ROBJECT_IV_INDEX_TBL
+#endif
 
 /* object.c */
 VALUE rb_class_search_ancestor(VALUE klass, VALUE super);
@@ -21,6 +26,7 @@ int rb_bool_expected(VALUE, const char *, int raise);
 static inline void RBASIC_CLEAR_CLASS(VALUE obj);
 static inline void RBASIC_SET_CLASS_RAW(VALUE obj, VALUE klass);
 static inline void RBASIC_SET_CLASS(VALUE obj, VALUE klass);
+static inline struct st_table *ROBJECT_IV_INDEX_TBL_inline(VALUE obj);
 
 RUBY_SYMBOL_EXPORT_BEGIN
 /* object.c (export) */
@@ -58,4 +64,20 @@ RBASIC_SET_CLASS(VALUE obj, VALUE klass)
     RBASIC_SET_CLASS_RAW(obj, klass);
     RB_OBJ_WRITTEN(obj, oldv, klass);
 }
+
+RBIMPL_ATTR_PURE()
+static inline struct st_table *
+ROBJECT_IV_INDEX_TBL_inline(VALUE obj)
+{
+    if (RB_FL_ANY_RAW(obj, ROBJECT_EMBED)) {
+        VALUE klass = rb_obj_class(obj);
+        return RCLASS_IV_INDEX_TBL(klass);
+    }
+    else {
+        const struct RObject *const ptr = ROBJECT(obj);
+        return ptr->as.heap.iv_index_tbl;
+    }
+}
+#define ROBJECT_IV_INDEX_TBL ROBJECT_IV_INDEX_TBL_inline
+
 #endif /* INTERNAL_OBJECT_H */
diff --git a/internal/variable.h b/internal/variable.h
index 47037a3392..1a19e8964b 100644
--- a/internal/variable.h
+++ b/internal/variable.h
@@ -37,9 +37,6 @@ static inline void ROBJ_TRANSIENT_SET(VALUE obj);
 static inline void ROBJ_TRANSIENT_UNSET(VALUE obj);
 uint32_t rb_obj_ensure_iv_index_mapping(VALUE obj, ID id);
 
-struct gen_ivtbl;
-int rb_gen_ivtbl_get(VALUE obj, ID id, struct gen_ivtbl **ivtbl);
-
 RUBY_SYMBOL_EXPORT_BEGIN
 /* variable.c (export) */
 void rb_mark_generic_ivar(VALUE);
@@ -55,8 +52,6 @@ VALUE rb_gvar_set(ID, VALUE);
 VALUE rb_gvar_defined(ID);
 void rb_const_warn_if_deprecated(const rb_const_entry_t *, VALUE, ID);
 void rb_init_iv_list(VALUE obj);
-void rb_ensure_iv_list_size(VALUE obj, uint32_t len, uint32_t newsize);
-struct gen_ivtbl * rb_ensure_generic_iv_list_size(VALUE obj, uint32_t newsize);
 MJIT_SYMBOL_EXPORT_END
 
 static inline bool