Reverting r62775, this should fix i686 builds

We need to mark default values for kwarg methods.  This also fixes
Bootsnap.  IBF iseq loading needed to mark iseqs as "having markable
objects".

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62851 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

7 files changed, 189 insertions, 73 deletions

diff --git a/compile.c b/compile.c
index 71f60b9b1b..68d4bf549a 100644
--- a/compile.c
+++ b/compile.c
@@ -563,15 +563,6 @@ APPEND_ELEM(ISEQ_ARG_DECLARE LINK_ANCHOR *const anchor, LINK_ELEMENT *before, LI
 #endif
 
 static int
-iseq_add_mark_object(const rb_iseq_t *iseq, VALUE v)
-{
-    if (!SPECIAL_CONST_P(v)) {
-	rb_iseq_add_mark_object(iseq, v);
-    }
-    return COMPILE_OK;
-}
-
-static int
 iseq_add_mark_object_compile_time(const rb_iseq_t *iseq, VALUE v)
 {
     if (!SPECIAL_CONST_P(v)) {
@@ -749,6 +740,7 @@ rb_iseq_translate_threaded_code(rb_iseq_t *iseq)
 	encoded[i] = (VALUE)table[insn];
 	i += len;
     }
+    FL_SET(iseq, ISEQ_TRANSLATED);
 #endif
     return COMPILE_OK;
 }
@@ -1235,7 +1227,7 @@ new_child_iseq(rb_iseq_t *iseq, const NODE *const node,
 				    rb_iseq_path(iseq), rb_iseq_realpath(iseq),
 				    INT2FIX(line_no), parent, type, ISEQ_COMPILE_DATA(iseq)->option);
     debugs("[new_child_iseq]< ---------------------------------------\n");
-    iseq_add_mark_object(iseq, (VALUE)ret_iseq);
+    iseq_add_mark_object_compile_time(iseq, (VALUE)ret_iseq);
     return ret_iseq;
 }
 
@@ -1250,7 +1242,7 @@ new_child_iseq_ifunc(rb_iseq_t *iseq, const struct vm_ifunc *ifunc,
 				 rb_iseq_path(iseq), rb_iseq_realpath(iseq),
 				 INT2FIX(line_no), parent, type, ISEQ_COMPILE_DATA(iseq)->option);
     debugs("[new_child_iseq_ifunc]< ---------------------------------------\n");
-    iseq_add_mark_object(iseq, (VALUE)ret_iseq);
+    iseq_add_mark_object_compile_time(iseq, (VALUE)ret_iseq);
     return ret_iseq;
 }
 
@@ -1566,7 +1558,7 @@ iseq_set_arguments_keywords(rb_iseq_t *iseq, LINK_ANCHOR *const optargs,
 	    switch (nd_type(val_node)) {
 	      case NODE_LIT:
 		dv = val_node->nd_lit;
-		iseq_add_mark_object(iseq, dv);
+		iseq_add_mark_object_compile_time(iseq, dv);
 		break;
 	      case NODE_NIL:
 		dv = Qnil;
@@ -2096,6 +2088,7 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 			    rb_hash_rehash(map);
 			    freeze_hide_obj(map);
 			    generated_iseq[code_index + 1 + j] = map;
+			    FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
 			    break;
 			}
 		      case TS_LINDEX:
@@ -2106,6 +2099,9 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 			{
 			    VALUE v = operands[j];
 			    generated_iseq[code_index + 1 + j] = v;
+			    if (!SPECIAL_CONST_P(v)) {
+				FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
+			    }
 			    break;
 			}
 		      case TS_VALUE:	/* VALUE */
@@ -2113,7 +2109,9 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 			    VALUE v = operands[j];
 			    generated_iseq[code_index + 1 + j] = v;
 			    /* to mark ruby object */
-			    iseq_add_mark_object(iseq, v);
+			    if (!SPECIAL_CONST_P(v)) {
+				FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
+			    }
 			    break;
 			}
 		      case TS_IC: /* inline cache */
@@ -2126,6 +2124,17 @@ iseq_set_sequence(rb_iseq_t *iseq, LINK_ANCHOR *const anchor)
 			    generated_iseq[code_index + 1 + j] = (VALUE)ic;
 			    break;
 			}
+		      case TS_ISE: /* inline storage entry */
+			{
+			    unsigned int ic_index = FIX2UINT(operands[j]);
+			    IC ic = (IC)&iseq->body->is_entries[ic_index];
+			    if (UNLIKELY(ic_index >= iseq->body->is_size)) {
+				rb_bug("iseq_set_sequence: ic_index overflow: index: %d, size: %d", ic_index, iseq->body->is_size);
+			    }
+			    generated_iseq[code_index + 1 + j] = (VALUE)ic;
+			    FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
+			    break;
+			}
 		      case TS_CALLINFO: /* call info */
 			{
 			    struct rb_call_info *base_ci = (struct rb_call_info *)operands[j];
@@ -2278,11 +2287,6 @@ iseq_set_exception_table(rb_iseq_t *iseq)
 	    entry->end = label_get_position((LABEL *)(ptr[2] & ~1));
 	    entry->iseq = (rb_iseq_t *)ptr[3];
 
-	    /* register iseq as mark object */
-	    if (entry->iseq != 0) {
-		iseq_add_mark_object(iseq, (VALUE)entry->iseq);
-	    }
-
 	    /* stack depth */
 	    if (ptr[4]) {
 		LABEL *lobj = (LABEL *)(ptr[4] & ~1);
@@ -4897,7 +4901,7 @@ compile_case(rb_iseq_t *iseq, LINK_ANCHOR *const ret, const NODE *const orig_nod
     }
 
     if (only_special_literals) {
-	iseq_add_mark_object(iseq, literals);
+	iseq_add_mark_object_compile_time(iseq, literals);
 
 	ADD_INSN(ret, nd_line(orig_node), dup);
 	ADD_INSN2(ret, nd_line(orig_node), opt_case_dispatch, literals, elselabel);
@@ -7374,6 +7378,7 @@ insn_data_to_s_detail(INSN *iobj)
 		    break;
 		}
 	      case TS_IC:	/* inline cache */
+	      case TS_ISE:	/* inline storage entry */
 		rb_str_catf(str, "<ic:%d>", FIX2INT(OPERAND_AT(iobj, j)));
 		break;
 	      case TS_CALLINFO: /* call info */
@@ -7613,7 +7618,6 @@ iseq_build_load_iseq(const rb_iseq_t *iseq, VALUE op)
     }
 
     loaded_iseq = rb_iseqw_to_iseq(iseqw);
-    iseq_add_mark_object(iseq, (VALUE)loaded_iseq);
     return loaded_iseq;
 }
 
@@ -7744,7 +7748,6 @@ iseq_build_from_ary_body(rb_iseq_t *iseq, LINK_ANCHOR *const anchor,
 			break;
 		      case TS_VALUE:
 			argv[j] = op;
-			iseq_add_mark_object(iseq, op);
 			break;
 		      case TS_ISEQ:
 			{
@@ -7761,6 +7764,7 @@ iseq_build_from_ary_body(rb_iseq_t *iseq, LINK_ANCHOR *const anchor,
 			argv[j] = (VALUE)rb_global_entry(SYM2ID(op));
 			break;
 		      case TS_IC:
+		      case TS_ISE:
 			argv[j] = op;
 			if (NUM2UINT(op) >= iseq->body->is_size) {
 			    iseq->body->is_size = NUM2INT(op) + 1;
@@ -7791,7 +7795,6 @@ iseq_build_from_ary_body(rb_iseq_t *iseq, LINK_ANCHOR *const anchor,
 			    }
 			    RB_GC_GUARD(op);
 			    argv[j] = map;
-			    rb_iseq_add_mark_object(iseq, map);
 			}
 			break;
 		      case TS_FUNCPTR:
@@ -8395,6 +8398,7 @@ ibf_dump_code(struct ibf_dump *dump, const rb_iseq_t *iseq)
 		code[code_index] = (VALUE)ibf_dump_iseq(dump, (const rb_iseq_t *)op);
 		break;
 	      case TS_IC:
+	      case TS_ISE:
 		{
 		    unsigned int i;
 		    for (i=0; i<iseq->body->is_size; i++) {
@@ -8455,11 +8459,15 @@ ibf_load_code(const struct ibf_load *load, const rb_iseq_t *iseq, const struct r
 	      case TS_CDHASH:
 	      case TS_VALUE:
 		code[code_index] = ibf_load_object(load, op);
+		FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
 		break;
 	      case TS_ISEQ:
 		code[code_index] = (VALUE)ibf_load_iseq(load, (const rb_iseq_t *)op);
+		FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
 		break;
 	      case TS_IC:
+		FL_SET(iseq, ISEQ_MARKABLE_ISEQ);
+	      case TS_ISE:
 		code[code_index] = (VALUE)&is_entries[(int)op];
 		break;
 	      case TS_CALLINFO:
@@ -8760,7 +8768,8 @@ ibf_dump_iseq_each(struct ibf_dump *dump, const rb_iseq_t *iseq)
     dump_body.is_entries =           NULL;
     dump_body.ci_entries =           ibf_dump_ci_entries(dump, iseq);
     dump_body.cc_entries =           NULL;
-    dump_body.mark_ary =             ISEQ_FLIP_CNT(iseq);
+    dump_body.variable.coverage      = Qnil;
+    dump_body.variable.original_iseq = Qnil;
 
     return ibf_dump_write(dump, &dump_body, sizeof(dump_body));
 }
@@ -8792,7 +8801,9 @@ ibf_load_iseq_each(const struct ibf_load *load, rb_iseq_t *iseq, ibf_offset_t of
     load_body->ci_kw_size = body->ci_kw_size;
     load_body->insns_info.size = body->insns_info.size;
 
-    RB_OBJ_WRITE(iseq, &load_body->mark_ary, iseq_mark_ary_create((int)body->mark_ary));
+    ISEQ_COVERAGE_SET(iseq, Qnil);
+    ISEQ_ORIGINAL_ISEQ_CLEAR(iseq);
+    iseq->body->variable.flip_count = body->variable.flip_count;
 
     {
 	VALUE realpath = Qnil, path = ibf_load_object(load, body->location.pathobj);
@@ -9433,7 +9444,6 @@ ibf_load_object(const struct ibf_load *load, VALUE object_index)
 
 	    rb_ary_store(load->obj_list, (long)object_index, obj);
 	}
-	iseq_add_mark_object(load->iseq, obj);
 	return obj;
     }
 }
@@ -9655,9 +9665,6 @@ ibf_load_iseq(const struct ibf_load *load, const rb_iseq_t *index_iseq)
 	    fprintf(stderr, "ibf_load_iseq: iseq=%p loaded %p\n",
 		    iseq, load->iseq);
 #endif
-	    if (load->iseq) {
-		iseq_add_mark_object(load->iseq, (VALUE)iseq);
-	    }
 	    return iseq;
 	}
     }
diff --git a/insns.def b/insns.def
index 73f2495ea9..da54e0a4b1 100644
--- a/insns.def
+++ b/insns.def
@@ -972,11 +972,11 @@ setinlinecache
 /* run iseq only once */
 DEFINE_INSN
 once
-(ISEQ iseq, IC ic)
+(ISEQ iseq, ISE ise)
 ()
 (VALUE val)
 {
-    val = vm_once_dispatch(ec, iseq, ic);
+    val = vm_once_dispatch(ec, iseq, ise);
 }
 
 /* case dispatcher, jump by table if possible */
diff --git a/iseq.c b/iseq.c
index 72e713bd52..d893f8154a 100644
--- a/iseq.c
+++ b/iseq.c
@@ -115,6 +115,100 @@ rb_iseq_free(const rb_iseq_t *iseq)
     RUBY_FREE_LEAVE("iseq");
 }
 
+#if OPT_DIRECT_THREADED_CODE || OPT_CALL_THREADED_CODE
+static VALUE
+rb_vm_insn_addr2insn2(const void *addr)
+{
+    VALUE insn;
+    const void * const *table = rb_vm_get_insns_address_table();
+
+    for (insn = 0; insn < VM_INSTRUCTION_SIZE; insn++) {
+	if (table[insn] == addr) {
+	    return insn;
+	}
+    }
+    rb_bug("rb_vm_insn_addr2insn: invalid insn address: %p", addr);
+}
+#endif
+
+static VALUE
+rb_vm_insn_null_translator(const void *addr)
+{
+    return (VALUE)addr;
+}
+
+typedef void iseq_value_itr_t(void *ctx, VALUE obj);
+typedef VALUE rb_vm_insns_translator_t(const void *addr);
+
+static int
+iseq_extract_values(const VALUE *code, size_t pos, iseq_value_itr_t * func, void *data, rb_vm_insns_translator_t * translator)
+{
+    VALUE insn = translator((void *)code[pos]);
+    int len = insn_len(insn);
+    int op_no;
+    const char *types = insn_op_types(insn);
+
+    for (op_no = 0; types[op_no]; op_no++) {
+	char type = types[op_no];
+	switch (type) {
+	    case TS_CDHASH:
+	    case TS_ISEQ:
+	    case TS_VALUE:
+		{
+		    VALUE op = code[pos + op_no + 1];
+		    if (!SPECIAL_CONST_P(op)) {
+			func(data, op);
+		    }
+		    break;
+		}
+	    case TS_ISE:
+		{
+		    union iseq_inline_storage_entry *const is = (union iseq_inline_storage_entry *)code[pos + op_no + 1];
+		    if (is->once.value) {
+			func(data, is->once.value);
+		    }
+		    break;
+		}
+	    default:
+		break;
+	}
+    }
+
+    return len;
+}
+
+static void
+rb_iseq_each_value(const rb_iseq_t *iseq, iseq_value_itr_t * func, void *data)
+{
+    unsigned int size;
+    const VALUE *code;
+    size_t n;
+    rb_vm_insns_translator_t * translator;
+
+    size = iseq->body->iseq_size;
+    code = iseq->body->iseq_encoded;
+
+#if OPT_DIRECT_THREADED_CODE || OPT_CALL_THREADED_CODE
+    if (FL_TEST(iseq, ISEQ_TRANSLATED)) {
+	translator = rb_vm_insn_addr2insn2;
+    } else {
+	translator = rb_vm_insn_null_translator;
+    }
+#else
+    translator = rb_vm_insn_null_translator;
+#endif
+
+    for (n = 0; n < size;) {
+	n += iseq_extract_values(code, n, func, data, translator);
+    }
+}
+
+static void
+each_insn_value(void *ctx, VALUE obj)
+{
+    rb_gc_mark(obj);
+}
+
 void
 rb_iseq_mark(const rb_iseq_t *iseq)
 {
@@ -123,13 +217,44 @@ rb_iseq_mark(const rb_iseq_t *iseq)
     if (iseq->body) {
 	const struct rb_iseq_constant_body *body = iseq->body;
 
-	RUBY_MARK_UNLESS_NULL(body->mark_ary);
+	if(FL_TEST(iseq, ISEQ_MARKABLE_ISEQ)) {
+	    rb_iseq_each_value(iseq, each_insn_value, NULL);
+	}
+
+	rb_gc_mark(body->variable.coverage);
+	rb_gc_mark(body->variable.original_iseq);
 	rb_gc_mark(body->location.label);
 	rb_gc_mark(body->location.base_label);
 	rb_gc_mark(body->location.pathobj);
 	RUBY_MARK_UNLESS_NULL((VALUE)body->parent_iseq);
+
+	if (body->param.flags.has_kw && ISEQ_COMPILE_DATA(iseq) == NULL) {
+	    int i, j;
+
+	    i = body->param.keyword->required_num;
+
+	    for (j = 0; i < body->param.keyword->num; i++, j++) {
+		VALUE obj = body->param.keyword->default_values[j];
+		if (obj != Qundef) {
+		    rb_gc_mark(obj);
+		}
+	    }
+	}
+
+	if (body->catch_table) {
+	    const struct iseq_catch_table *table = body->catch_table;
+	    unsigned int i;
+	    for(i = 0; i < table->size; i++) {
+		const struct iseq_catch_table_entry *entry;
+		entry = &table->entries[i];
+		if (entry->iseq) {
+		    rb_gc_mark((VALUE)entry->iseq);
+		}
+	    }
+	}
     }
 
+
     if (FL_TEST(iseq, ISEQ_NOT_LOADED_YET)) {
 	rb_gc_mark(iseq->aux.loader.obj);
     }
@@ -299,13 +424,6 @@ set_relation(rb_iseq_t *iseq, const rb_iseq_t *piseq)
     }
 }
 
-void
-rb_iseq_add_mark_object(const rb_iseq_t *iseq, VALUE obj)
-{
-    /* TODO: check dedup */
-    rb_ary_push(ISEQ_MARK_ARY(iseq), obj);
-}
-
 static VALUE
 prepare_iseq_build(rb_iseq_t *iseq,
 		   VALUE name, VALUE path, VALUE realpath, VALUE first_lineno, const rb_code_location_t *code_location,
@@ -326,7 +444,9 @@ prepare_iseq_build(rb_iseq_t *iseq,
     if (iseq != iseq->body->local_iseq) {
 	RB_OBJ_WRITE(iseq, &iseq->body->location.base_label, iseq->body->local_iseq->body->location.label);
     }
-    RB_OBJ_WRITE(iseq, &iseq->body->mark_ary, iseq_mark_ary_create(0));
+    ISEQ_COVERAGE_SET(iseq, Qnil);
+    ISEQ_ORIGINAL_ISEQ_CLEAR(iseq);
+    iseq->body->variable.flip_count = 0;
 
     ISEQ_COMPILE_DATA_ALLOC(iseq);
     RB_OBJ_WRITE(iseq, &ISEQ_COMPILE_DATA(iseq)->err_info, err_info);
@@ -1618,6 +1738,7 @@ rb_insn_operand_intern(const rb_iseq_t *iseq,
 	break;
 
       case TS_IC:
+      case TS_ISE:
 	ret = rb_sprintf("<is:%"PRIdPTRDIFF">", (union iseq_inline_storage_entry *)op - iseq->body->is_entries);
 	break;
 
@@ -2363,6 +2484,7 @@ iseq_data_to_ary(const rb_iseq_t *iseq)
 		}
 		break;
 	      case TS_IC:
+	      case TS_ISE:
 		{
 		    union iseq_inline_storage_entry *is = (union iseq_inline_storage_entry *)*seq;
 		    rb_ary_push(ary, INT2FIX(is - iseq->body->is_entries));
diff --git a/iseq.h b/iseq.h
index 0c316e2cb2..0a0edd9b7a 100644
--- a/iseq.h
+++ b/iseq.h
@@ -28,44 +28,25 @@ rb_call_info_kw_arg_bytes(int keyword_len)
     return sizeof(struct rb_call_info_kw_arg) + sizeof(VALUE) * (keyword_len - 1);
 }
 
-enum iseq_mark_ary_index {
-    ISEQ_MARK_ARY_COVERAGE,
-    ISEQ_MARK_ARY_FLIP_CNT,
-    ISEQ_MARK_ARY_ORIGINAL_ISEQ,
-    ISEQ_MARK_ARY_INITIAL_SIZE
-};
-
-static inline VALUE
-iseq_mark_ary_create(int flip_cnt)
-{
-    VALUE ary = rb_ary_tmp_new(ISEQ_MARK_ARY_INITIAL_SIZE);
-    rb_ary_push(ary, Qnil);              /* ISEQ_MARK_ARY_COVERAGE */
-    rb_ary_push(ary, INT2FIX(flip_cnt)); /* ISEQ_MARK_ARY_FLIP_CNT */
-    rb_ary_push(ary, Qnil);              /* ISEQ_MARK_ARY_ORIGINAL_ISEQ */
-    return ary;
-}
-
-#define ISEQ_MARK_ARY(iseq)           (iseq)->body->mark_ary
-
-#define ISEQ_COVERAGE(iseq)           RARRAY_AREF(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_COVERAGE)
-#define ISEQ_COVERAGE_SET(iseq, cov)  RARRAY_ASET(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_COVERAGE, cov)
+#define ISEQ_COVERAGE(iseq)           iseq->body->variable.coverage
+#define ISEQ_COVERAGE_SET(iseq, cov)  RB_OBJ_WRITE(iseq, &iseq->body->variable.coverage, cov)
 #define ISEQ_LINE_COVERAGE(iseq)      RARRAY_AREF(ISEQ_COVERAGE(iseq), COVERAGE_INDEX_LINES)
 #define ISEQ_BRANCH_COVERAGE(iseq)    RARRAY_AREF(ISEQ_COVERAGE(iseq), COVERAGE_INDEX_BRANCHES)
 
-#define ISEQ_FLIP_CNT(iseq) FIX2INT(RARRAY_AREF(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_FLIP_CNT))
+#define ISEQ_FLIP_CNT(iseq) (iseq)->body->variable.flip_count
 
-static inline int
+static inline rb_snum_t
 ISEQ_FLIP_CNT_INCREMENT(const rb_iseq_t *iseq)
 {
-    int cnt = ISEQ_FLIP_CNT(iseq);
-    RARRAY_ASET(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_FLIP_CNT, INT2FIX(cnt+1));
+    rb_snum_t cnt = iseq->body->variable.flip_count;
+    iseq->body->variable.flip_count += 1;
     return cnt;
 }
 
 static inline VALUE *
 ISEQ_ORIGINAL_ISEQ(const rb_iseq_t *iseq)
 {
-    VALUE str = RARRAY_AREF(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_ORIGINAL_ISEQ);
+    VALUE str = iseq->body->variable.original_iseq;
     if (RTEST(str)) return (VALUE *)RSTRING_PTR(str);
     return NULL;
 }
@@ -73,14 +54,14 @@ ISEQ_ORIGINAL_ISEQ(const rb_iseq_t *iseq)
 static inline void
 ISEQ_ORIGINAL_ISEQ_CLEAR(const rb_iseq_t *iseq)
 {
-    RARRAY_ASET(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_ORIGINAL_ISEQ, Qnil);
+    RB_OBJ_WRITE(iseq, &iseq->body->variable.original_iseq, Qnil);
 }
 
 static inline VALUE *
 ISEQ_ORIGINAL_ISEQ_ALLOC(const rb_iseq_t *iseq, long size)
 {
     VALUE str = rb_str_tmp_new(size * sizeof(VALUE));
-    RARRAY_ASET(ISEQ_MARK_ARY(iseq), ISEQ_MARK_ARY_ORIGINAL_ISEQ, str);
+    RB_OBJ_WRITE(iseq, &iseq->body->variable.original_iseq, str);
     return (VALUE *)RSTRING_PTR(str);
 }
 
@@ -94,6 +75,8 @@ ISEQ_ORIGINAL_ISEQ_ALLOC(const rb_iseq_t *iseq, long size)
 
 #define ISEQ_NOT_LOADED_YET   IMEMO_FL_USER1
 #define ISEQ_USE_COMPILE_DATA IMEMO_FL_USER2
+#define ISEQ_TRANSLATED       IMEMO_FL_USER3
+#define ISEQ_MARKABLE_ISEQ    IMEMO_FL_USER4
 
 struct iseq_compile_data {
     /* GC is needed */
@@ -173,7 +156,6 @@ void rb_iseq_build_from_ary(rb_iseq_t *iseq, VALUE misc,
 			    VALUE exception, VALUE body);
 
 /* iseq.c */
-void rb_iseq_add_mark_object(const rb_iseq_t *iseq, VALUE obj);
 VALUE rb_iseq_load(VALUE data, VALUE parent, VALUE opt);
 VALUE rb_iseq_parameters(const rb_iseq_t *iseq, int is_proc);
 struct st_table *ruby_insn_make_insn_table(void);
diff --git a/tool/ruby_vm/models/typemap.rb b/tool/ruby_vm/models/typemap.rb
index d818ce9878..7c5c872d7c 100644
--- a/tool/ruby_vm/models/typemap.rb
+++ b/tool/ruby_vm/models/typemap.rb
@@ -18,6 +18,7 @@ RubyVM::Typemap = {
   "GENTRY"         => %w[G TS_GENTRY],
   "IC"             => %w[K TS_IC],
   "ID"             => %w[I TS_ID],
+  "ISE"            => %w[T TS_ISE],
   "ISEQ"           => %w[S TS_ISEQ],
   "OFFSET"         => %w[O TS_OFFSET],
   "VALUE"          => %w[V TS_VALUE],
diff --git a/vm_core.h b/vm_core.h
index 4e7eaed199..9b8aede35c 100644
--- a/vm_core.h
+++ b/vm_core.h
@@ -411,7 +411,11 @@ struct rb_iseq_constant_body {
 				      */
     struct rb_call_cache *cc_entries; /* size is ci_size = ci_kw_size */
 
-    VALUE mark_ary;     /* Array: includes operands which should be GC marked */
+    struct {
+      rb_snum_t flip_count;
+      VALUE coverage;
+      VALUE original_iseq;
+    } variable;
 
     unsigned int local_table_size;
     unsigned int is_size;
@@ -1010,6 +1014,7 @@ enum vm_svar_index {
 
 /* inline cache */
 typedef struct iseq_inline_cache_entry *IC;
+typedef union iseq_inline_storage_entry *ISE;
 typedef struct rb_call_info *CALL_INFO;
 typedef struct rb_call_cache *CALL_CACHE;
 
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 0bab81e906..0f365db3f5 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -3282,11 +3282,10 @@ vm_ic_update(IC ic, VALUE val, const VALUE *reg_ep)
 }
 
 static VALUE
-vm_once_dispatch(rb_execution_context_t *ec, ISEQ iseq, IC ic)
+vm_once_dispatch(rb_execution_context_t *ec, ISEQ iseq, ISE is)
 {
     rb_thread_t *th = rb_ec_thread_ptr(ec);
     rb_thread_t *const RUNNING_THREAD_ONCE_DONE = (rb_thread_t *)(0x1);
-    union iseq_inline_storage_entry *const is = (union iseq_inline_storage_entry *)ic;
 
   again:
     if (is->once.running_thread == RUNNING_THREAD_ONCE_DONE) {
@@ -3295,10 +3294,10 @@ vm_once_dispatch(rb_execution_context_t *ec, ISEQ iseq, IC ic)
     else if (is->once.running_thread == NULL) {
 	VALUE val;
 	is->once.running_thread = th;
-	val = is->once.value = rb_ensure(vm_once_exec, (VALUE)iseq, vm_once_clear, (VALUE)is);
+	val = rb_ensure(vm_once_exec, (VALUE)iseq, vm_once_clear, (VALUE)is);
+	RB_OBJ_WRITE(ec->cfp->iseq, &is->once.value, val);
 	/* is->once.running_thread is cleared by vm_once_clear() */
 	is->once.running_thread = RUNNING_THREAD_ONCE_DONE; /* success */
-	rb_iseq_add_mark_object(ec->cfp->iseq, val);
 	return val;
     }
     else if (is->once.running_thread == th) {