Place all non-default GC API behind USE_SHARED_GC

So that it doesn't get included in the generated binaries for builds
that don't support loading shared GC modules

Co-Authored-By: Peter Zhu <[email protected]>

12 files changed, 294 insertions, 9491 deletions

diff --git a/gc.c b/gc.c
index efd19cce71..b2afd55705 100644
--- a/gc.c
+++ b/gc.c
@@ -178,10 +178,67 @@ rb_gc_vm_barrier(void)
     rb_vm_barrier();
 }
 
+#if USE_SHARED_GC
+void *
+rb_gc_get_ractor_newobj_cache(void)
+{
+    return GET_RACTOR()->newobj_cache;
+}
+
+void
+rb_gc_initialize_vm_context(struct rb_gc_vm_context *context)
+{
+    rb_native_mutex_initialize(&context->lock);
+    context->ec = GET_EC();
+}
+
+void
+rb_gc_worker_thread_set_vm_context(struct rb_gc_vm_context *context)
+{
+    rb_native_mutex_lock(&context->lock);
+
+    GC_ASSERT(rb_current_execution_context(false) == NULL);
+
+#ifdef RB_THREAD_LOCAL_SPECIFIER
+# ifdef __APPLE__
+    rb_current_ec_set(context->ec);
+# else
+    ruby_current_ec = context->ec;
+# endif
+#else
+    native_tls_set(ruby_current_ec_key, context->ec);
+#endif
+}
+
+void
+rb_gc_worker_thread_unset_vm_context(struct rb_gc_vm_context *context)
+{
+    rb_native_mutex_unlock(&context->lock);
+
+    GC_ASSERT(rb_current_execution_context(true) == context->ec);
+
+#ifdef RB_THREAD_LOCAL_SPECIFIER
+# ifdef __APPLE__
+    rb_current_ec_set(NULL);
+# else
+    ruby_current_ec = NULL;
+# endif
+#else
+    native_tls_set(ruby_current_ec_key, NULL);
+#endif
+}
+#endif
+
+bool
+rb_gc_event_hook_required_p(rb_event_flag_t event)
+{
+    return ruby_vm_event_flags & event;
+}
+
 void
 rb_gc_event_hook(VALUE obj, rb_event_flag_t event)
 {
-    if (LIKELY(!(ruby_vm_event_flags & event))) return;
+    if (LIKELY(!rb_gc_event_hook_required_p(event))) return;
 
     rb_execution_context_t *ec = GET_EC();
     if (!ec->cfp) return;
@@ -195,6 +252,7 @@ rb_gc_get_objspace(void)
     return GET_VM()->gc.objspace;
 }
 
+
 void
 rb_gc_ractor_newobj_cache_foreach(void (*func)(void *cache, void *data), void *data)
 {
@@ -1167,11 +1225,6 @@ rb_gc_obj_free(void *objspace, VALUE obj)
         break;
     }
 
-    if (FL_TEST(obj, FL_EXIVAR)) {
-        rb_free_generic_ivar((VALUE)obj);
-        FL_UNSET(obj, FL_EXIVAR);
-    }
-
     switch (BUILTIN_TYPE(obj)) {
       case T_OBJECT:
         if (rb_shape_obj_too_complex(obj)) {
@@ -1355,10 +1408,7 @@ rb_gc_obj_free(void *objspace, VALUE obj)
         break;
 
       case T_SYMBOL:
-        {
-            rb_gc_free_dsymbol(obj);
-            RB_DEBUG_COUNTER_INC(obj_symbol);
-        }
+        RB_DEBUG_COUNTER_INC(obj_symbol);
         break;
 
       case T_IMEMO:
@@ -2361,10 +2411,16 @@ rb_mark_locations(void *begin, void *end)
     rb_stack_range_tmp[1] = end;
 }
 
+void
+rb_gc_save_machine_context(void)
+{
+    // no-op
+}
+
 # if defined(__EMSCRIPTEN__)
 
 static void
-mark_current_machine_context(rb_execution_context_t *ec)
+mark_current_machine_context(const rb_execution_context_t *ec)
 {
     emscripten_scan_stack(rb_mark_locations);
     each_location_ptr(rb_stack_range_tmp[0], rb_stack_range_tmp[1], gc_mark_maybe_each_location, NULL);
@@ -2375,7 +2431,7 @@ mark_current_machine_context(rb_execution_context_t *ec)
 # else // use Asyncify version
 
 static void
-mark_current_machine_context(rb_execution_context_t *ec)
+mark_current_machine_context(const rb_execution_context_t *ec)
 {
     VALUE *stack_start, *stack_end;
     SET_STACK_END;
@@ -2390,35 +2446,19 @@ mark_current_machine_context(rb_execution_context_t *ec)
 
 #else // !defined(__wasm__)
 
-static void
-mark_current_machine_context(rb_execution_context_t *ec)
+void
+rb_gc_save_machine_context(void)
 {
-    union {
-        rb_jmp_buf j;
-        VALUE v[sizeof(rb_jmp_buf) / (sizeof(VALUE))];
-    } save_regs_gc_mark;
-    VALUE *stack_start, *stack_end;
-
-    FLUSH_REGISTER_WINDOWS;
-    memset(&save_regs_gc_mark, 0, sizeof(save_regs_gc_mark));
-    /* This assumes that all registers are saved into the jmp_buf (and stack) */
-    rb_setjmp(save_regs_gc_mark.j);
+    rb_thread_t *thread = GET_THREAD();
 
-    /* SET_STACK_END must be called in this function because
-     * the stack frame of this function may contain
-     * callee save registers and they should be marked. */
-    SET_STACK_END;
-    GET_STACK_BOUNDS(stack_start, stack_end, 1);
+    RB_VM_SAVE_MACHINE_CONTEXT(thread);
+}
 
-    void *data =
-#ifdef RUBY_ASAN_ENABLED
-        ec;
-#else
-        NULL;
-#endif
 
-    each_location(save_regs_gc_mark.v, numberof(save_regs_gc_mark.v), gc_mark_machine_stack_location_maybe, data);
-    each_location_ptr(stack_start, stack_end, gc_mark_machine_stack_location_maybe, data);
+static void
+mark_current_machine_context(const rb_execution_context_t *ec)
+{
+    rb_gc_mark_machine_context(ec);
 }
 #endif
 
@@ -2526,9 +2566,6 @@ rb_gc_mark_roots(void *objspace, const char **categoryp)
     rb_vm_mark(vm);
     if (vm->self) gc_mark_internal(vm->self);
 
-    MARK_CHECKPOINT("machine_context");
-    mark_current_machine_context(ec);
-
     MARK_CHECKPOINT("end_proc");
     rb_mark_end_proc();
 
@@ -2544,7 +2581,11 @@ rb_gc_mark_roots(void *objspace, const char **categoryp)
     }
 #endif
 
+    MARK_CHECKPOINT("machine_context");
+    mark_current_machine_context(ec);
+
     MARK_CHECKPOINT("finish");
+
 #undef MARK_CHECKPOINT
 }
 
@@ -2832,13 +2873,14 @@ const char *
 rb_gc_active_gc_name(void)
 {
     const char *gc_name = rb_gc_impl_active_gc_name();
+
     const size_t len = strlen(gc_name);
     if (len > RB_GC_MAX_NAME_LEN) {
         rb_bug("GC should have a name no more than %d chars long. Currently: %zu (%s)",
                RB_GC_MAX_NAME_LEN, len, gc_name);
     }
-    return gc_name;
 
+    return gc_name;
 }
 
 // TODO: rearchitect this function to work for a generic GC
@@ -2851,9 +2893,9 @@ rb_obj_gc_flags(VALUE obj, ID* flags, size_t max)
 /* GC */
 
 void *
-rb_gc_ractor_cache_alloc(void)
+rb_gc_ractor_cache_alloc(rb_ractor_t *ractor)
 {
-    return rb_gc_impl_ractor_cache_alloc(rb_gc_get_objspace());
+    return rb_gc_impl_ractor_cache_alloc(rb_gc_get_objspace(), ractor);
 }
 
 void
@@ -3246,6 +3288,142 @@ update_superclasses(void *objspace, VALUE obj)
 extern rb_symbols_t ruby_global_symbols;
 #define global_symbols ruby_global_symbols
 
+#if USE_SHARED_GC
+struct global_vm_table_foreach_data {
+    vm_table_foreach_callback_func callback;
+    vm_table_update_callback_func update_callback;
+    void *data;
+};
+
+static int
+vm_weak_table_foreach_key(st_data_t key, st_data_t value, st_data_t data, int error)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    return iter_data->callback((VALUE)key, iter_data->data);
+}
+
+static int
+vm_weak_table_foreach_update_key(st_data_t *key, st_data_t *value, st_data_t data, int existing)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    return iter_data->update_callback((VALUE *)key, iter_data->data);
+}
+
+static int
+vm_weak_table_str_sym_foreach(st_data_t key, st_data_t value, st_data_t data, int error)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    if (STATIC_SYM_P(value)) {
+        return ST_CONTINUE;
+    }
+    else {
+        return iter_data->callback((VALUE)value, iter_data->data);
+    }
+}
+
+static int
+vm_weak_table_foreach_update_value(st_data_t *key, st_data_t *value, st_data_t data, int existing)
+{
+    struct global_vm_table_foreach_data *iter_data = (struct global_vm_table_foreach_data *)data;
+
+    return iter_data->update_callback((VALUE *)value, iter_data->data);
+}
+
+static int
+vm_weak_table_gen_ivar_foreach(st_data_t key, st_data_t value, st_data_t data, int error)
+{
+    int retval = vm_weak_table_foreach_key(key, value, data, error);
+    if (retval == ST_DELETE) {
+        FL_UNSET((VALUE)key, FL_EXIVAR);
+    }
+    return retval;
+}
+
+static int
+vm_weak_table_frozen_strings_foreach(st_data_t key, st_data_t value, st_data_t data, int error)
+{
+    GC_ASSERT(RB_TYPE_P((VALUE)key, T_STRING));
+
+    int retval = vm_weak_table_foreach_key(key, value, data, error);
+    if (retval == ST_DELETE) {
+        FL_UNSET((VALUE)key, RSTRING_FSTR);
+    }
+    return retval;
+}
+
+struct st_table *rb_generic_ivtbl_get(void);
+
+void
+rb_gc_vm_weak_table_foreach(vm_table_foreach_callback_func callback,
+                            vm_table_update_callback_func update_callback,
+                            void *data,
+                            enum rb_gc_vm_weak_tables table)
+{
+    rb_vm_t *vm = GET_VM();
+
+    struct global_vm_table_foreach_data foreach_data = {
+        .callback = callback,
+        .update_callback = update_callback,
+        .data = data
+    };
+
+    switch (table) {
+      case RB_GC_VM_CI_TABLE: {
+        st_foreach_with_replace(
+            vm->ci_table,
+            vm_weak_table_foreach_key,
+            vm_weak_table_foreach_update_key,
+            (st_data_t)&foreach_data
+        );
+        break;
+      }
+      case RB_GC_VM_OVERLOADED_CME_TABLE: {
+        st_foreach_with_replace(
+            vm->overloaded_cme_table,
+            vm_weak_table_foreach_key,
+            vm_weak_table_foreach_update_key,
+            (st_data_t)&foreach_data
+        );
+        break;
+      }
+      case RB_GC_VM_GLOBAL_SYMBOLS_TABLE: {
+        st_foreach_with_replace(
+            global_symbols.str_sym,
+            vm_weak_table_str_sym_foreach,
+            vm_weak_table_foreach_update_value,
+            (st_data_t)&foreach_data
+        );
+        break;
+      }
+      case RB_GC_VM_GENERIC_IV_TABLE: {
+        st_table *generic_iv_tbl = rb_generic_ivtbl_get();
+        st_foreach_with_replace(
+            generic_iv_tbl,
+            vm_weak_table_gen_ivar_foreach,
+            vm_weak_table_foreach_update_key,
+            (st_data_t)&foreach_data
+        );
+        break;
+      }
+      case RB_GC_VM_FROZEN_STRINGS_TABLE: {
+        st_table *frozen_strings = GET_VM()->frozen_strings;
+        st_foreach_with_replace(
+            frozen_strings,
+            vm_weak_table_frozen_strings_foreach,
+            vm_weak_table_foreach_update_key,
+            (st_data_t)&foreach_data
+        );
+        break;
+      }
+      default:
+        rb_bug("rb_gc_vm_weak_table_foreach: unknown table %d", table);
+    }
+}
+#endif
+
 void
 rb_gc_update_vm_references(void *objspace)
 {
@@ -3727,7 +3905,8 @@ rb_objspace_reachable_objects_from_root(void (func)(const char *category, VALUE,
     };
 
     vm->gc.mark_func_data = &mfd;
-    rb_gc_mark_roots(rb_gc_get_objspace(), &data.category);
+    rb_gc_save_machine_context();
+    rb_gc_mark_roots(vm->gc.objspace, &data.category);
     vm->gc.mark_func_data = prev_mfd;
 }
 
@@ -4473,6 +4652,18 @@ rb_obj_info_dump_loc(VALUE obj, const char *file, int line, const char *func)
     fprintf(stderr, "<OBJ_INFO:%s@%s:%d> %s\n", func, file, line, rb_raw_obj_info(buff, 0x100, obj));
 }
 
+void
+rb_gc_before_fork(void)
+{
+    rb_gc_impl_before_fork(rb_gc_get_objspace());
+}
+
+void
+rb_gc_after_fork(rb_pid_t pid)
+{
+    rb_gc_impl_after_fork(rb_gc_get_objspace(), pid);
+}
+
 /*
  * Document-module: ObjectSpace
  *
diff --git a/gc/default.c b/gc/default.c
deleted file mode 100644
index 89fad35a46..0000000000
--- a/gc/default.c
+++ /dev/null
@@ -1,9431 +0,0 @@
-#include "ruby/internal/config.h"
-
-#include <signal.h>
-
-#ifndef _WIN32
-# include <sys/mman.h>
-# include <unistd.h>
-# ifdef HAVE_SYS_PRCTL_H
-#  include <sys/prctl.h>
-# endif
-#endif
-
-#if !defined(PAGE_SIZE) && defined(HAVE_SYS_USER_H)
-/* LIST_HEAD conflicts with sys/queue.h on macOS */
-# include <sys/user.h>
-#endif
-
-#include "internal/hash.h"
-
-#include "ruby/ruby.h"
-#include "ruby/atomic.h"
-#include "ruby/debug.h"
-#include "ruby/thread.h"
-#include "ruby/util.h"
-#include "ruby/vm.h"
-#include "ruby/internal/encoding/string.h"
-#include "ccan/list/list.h"
-#include "darray.h"
-#include "gc/gc.h"
-#include "gc/gc_impl.h"
-
-#ifndef BUILDING_SHARED_GC
-# include "probes.h"
-#endif
-
-#include "debug_counter.h"
-#include "internal/sanitizers.h"
-
-/* MALLOC_HEADERS_BEGIN */
-#ifndef HAVE_MALLOC_USABLE_SIZE
-# ifdef _WIN32
-#  define HAVE_MALLOC_USABLE_SIZE
-#  define malloc_usable_size(a) _msize(a)
-# elif defined HAVE_MALLOC_SIZE
-#  define HAVE_MALLOC_USABLE_SIZE
-#  define malloc_usable_size(a) malloc_size(a)
-# endif
-#endif
-
-#ifdef HAVE_MALLOC_USABLE_SIZE
-# ifdef RUBY_ALTERNATIVE_MALLOC_HEADER
-/* Alternative malloc header is included in ruby/missing.h */
-# elif defined(HAVE_MALLOC_H)
-#  include <malloc.h>
-# elif defined(HAVE_MALLOC_NP_H)
-#  include <malloc_np.h>
-# elif defined(HAVE_MALLOC_MALLOC_H)
-#  include <malloc/malloc.h>
-# endif
-#endif
-
-#ifdef HAVE_MALLOC_TRIM
-# include <malloc.h>
-
-# ifdef __EMSCRIPTEN__
-/* malloc_trim is defined in emscripten/emmalloc.h on emscripten. */
-#  include <emscripten/emmalloc.h>
-# endif
-#endif
-
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-# include <mach/task.h>
-# include <mach/mach_init.h>
-# include <mach/mach_port.h>
-#endif
-
-#ifndef VM_CHECK_MODE
-# define VM_CHECK_MODE RUBY_DEBUG
-#endif
-
-// From ractor_core.h
-#ifndef RACTOR_CHECK_MODE
-# define RACTOR_CHECK_MODE (VM_CHECK_MODE || RUBY_DEBUG) && (SIZEOF_UINT64_T == SIZEOF_VALUE)
-#endif
-
-#ifndef RUBY_DEBUG_LOG
-# define RUBY_DEBUG_LOG(...)
-#endif
-
-#ifndef GC_HEAP_INIT_SLOTS
-#define GC_HEAP_INIT_SLOTS 10000
-#endif
-#ifndef GC_HEAP_FREE_SLOTS
-#define GC_HEAP_FREE_SLOTS  4096
-#endif
-#ifndef GC_HEAP_GROWTH_FACTOR
-#define GC_HEAP_GROWTH_FACTOR 1.8
-#endif
-#ifndef GC_HEAP_GROWTH_MAX_SLOTS
-#define GC_HEAP_GROWTH_MAX_SLOTS 0 /* 0 is disable */
-#endif
-#ifndef GC_HEAP_REMEMBERED_WB_UNPROTECTED_OBJECTS_LIMIT_RATIO
-# define GC_HEAP_REMEMBERED_WB_UNPROTECTED_OBJECTS_LIMIT_RATIO 0.01
-#endif
-#ifndef GC_HEAP_OLDOBJECT_LIMIT_FACTOR
-#define GC_HEAP_OLDOBJECT_LIMIT_FACTOR 2.0
-#endif
-
-#ifndef GC_HEAP_FREE_SLOTS_MIN_RATIO
-#define GC_HEAP_FREE_SLOTS_MIN_RATIO  0.20
-#endif
-#ifndef GC_HEAP_FREE_SLOTS_GOAL_RATIO
-#define GC_HEAP_FREE_SLOTS_GOAL_RATIO 0.40
-#endif
-#ifndef GC_HEAP_FREE_SLOTS_MAX_RATIO
-#define GC_HEAP_FREE_SLOTS_MAX_RATIO  0.65
-#endif
-
-#ifndef GC_MALLOC_LIMIT_MIN
-#define GC_MALLOC_LIMIT_MIN (16 * 1024 * 1024 /* 16MB */)
-#endif
-#ifndef GC_MALLOC_LIMIT_MAX
-#define GC_MALLOC_LIMIT_MAX (32 * 1024 * 1024 /* 32MB */)
-#endif
-#ifndef GC_MALLOC_LIMIT_GROWTH_FACTOR
-#define GC_MALLOC_LIMIT_GROWTH_FACTOR 1.4
-#endif
-
-#ifndef GC_OLDMALLOC_LIMIT_MIN
-#define GC_OLDMALLOC_LIMIT_MIN (16 * 1024 * 1024 /* 16MB */)
-#endif
-#ifndef GC_OLDMALLOC_LIMIT_GROWTH_FACTOR
-#define GC_OLDMALLOC_LIMIT_GROWTH_FACTOR 1.2
-#endif
-#ifndef GC_OLDMALLOC_LIMIT_MAX
-#define GC_OLDMALLOC_LIMIT_MAX (128 * 1024 * 1024 /* 128MB */)
-#endif
-
-#ifndef GC_CAN_COMPILE_COMPACTION
-#if defined(__wasi__) /* WebAssembly doesn't support signals */
-# define GC_CAN_COMPILE_COMPACTION 0
-#else
-# define GC_CAN_COMPILE_COMPACTION 1
-#endif
-#endif
-
-#ifndef PRINT_ENTER_EXIT_TICK
-# define PRINT_ENTER_EXIT_TICK 0
-#endif
-#ifndef PRINT_ROOT_TICKS
-#define PRINT_ROOT_TICKS 0
-#endif
-
-#define USE_TICK_T                 (PRINT_ENTER_EXIT_TICK || PRINT_ROOT_TICKS)
-
-#ifndef HEAP_COUNT
-# define HEAP_COUNT 5
-#endif
-
-typedef struct ractor_newobj_heap_cache {
-    struct free_slot *freelist;
-    struct heap_page *using_page;
-} rb_ractor_newobj_heap_cache_t;
-
-typedef struct ractor_newobj_cache {
-    size_t incremental_mark_step_allocated_slots;
-    rb_ractor_newobj_heap_cache_t heap_caches[HEAP_COUNT];
-} rb_ractor_newobj_cache_t;
-
-typedef struct {
-    size_t heap_init_slots[HEAP_COUNT];
-    size_t heap_free_slots;
-    double growth_factor;
-    size_t growth_max_slots;
-
-    double heap_free_slots_min_ratio;
-    double heap_free_slots_goal_ratio;
-    double heap_free_slots_max_ratio;
-    double uncollectible_wb_unprotected_objects_limit_ratio;
-    double oldobject_limit_factor;
-
-    size_t malloc_limit_min;
-    size_t malloc_limit_max;
-    double malloc_limit_growth_factor;
-
-    size_t oldmalloc_limit_min;
-    size_t oldmalloc_limit_max;
-    double oldmalloc_limit_growth_factor;
-} ruby_gc_params_t;
-
-static ruby_gc_params_t gc_params = {
-    { GC_HEAP_INIT_SLOTS },
-    GC_HEAP_FREE_SLOTS,
-    GC_HEAP_GROWTH_FACTOR,
-    GC_HEAP_GROWTH_MAX_SLOTS,
-
-    GC_HEAP_FREE_SLOTS_MIN_RATIO,
-    GC_HEAP_FREE_SLOTS_GOAL_RATIO,
-    GC_HEAP_FREE_SLOTS_MAX_RATIO,
-    GC_HEAP_REMEMBERED_WB_UNPROTECTED_OBJECTS_LIMIT_RATIO,
-    GC_HEAP_OLDOBJECT_LIMIT_FACTOR,
-
-    GC_MALLOC_LIMIT_MIN,
-    GC_MALLOC_LIMIT_MAX,
-    GC_MALLOC_LIMIT_GROWTH_FACTOR,
-
-    GC_OLDMALLOC_LIMIT_MIN,
-    GC_OLDMALLOC_LIMIT_MAX,
-    GC_OLDMALLOC_LIMIT_GROWTH_FACTOR,
-};
-
-/* GC_DEBUG:
- *  enable to embed GC debugging information.
- */
-#ifndef GC_DEBUG
-#define GC_DEBUG 0
-#endif
-
-/* RGENGC_DEBUG:
- * 1: basic information
- * 2: remember set operation
- * 3: mark
- * 4:
- * 5: sweep
- */
-#ifndef RGENGC_DEBUG
-#ifdef RUBY_DEVEL
-#define RGENGC_DEBUG       -1
-#else
-#define RGENGC_DEBUG       0
-#endif
-#endif
-#if RGENGC_DEBUG < 0 && !defined(_MSC_VER)
-# define RGENGC_DEBUG_ENABLED(level) (-(RGENGC_DEBUG) >= (level) && ruby_rgengc_debug >= (level))
-#elif defined(HAVE_VA_ARGS_MACRO)
-# define RGENGC_DEBUG_ENABLED(level) ((RGENGC_DEBUG) >= (level))
-#else
-# define RGENGC_DEBUG_ENABLED(level) 0
-#endif
-int ruby_rgengc_debug;
-
-/* RGENGC_PROFILE
- * 0: disable RGenGC profiling
- * 1: enable profiling for basic information
- * 2: enable profiling for each types
- */
-#ifndef RGENGC_PROFILE
-# define RGENGC_PROFILE     0
-#endif
-
-/* RGENGC_ESTIMATE_OLDMALLOC
- * Enable/disable to estimate increase size of malloc'ed size by old objects.
- * If estimation exceeds threshold, then will invoke full GC.
- * 0: disable estimation.
- * 1: enable estimation.
- */
-#ifndef RGENGC_ESTIMATE_OLDMALLOC
-# define RGENGC_ESTIMATE_OLDMALLOC 1
-#endif
-
-#ifndef GC_PROFILE_MORE_DETAIL
-# define GC_PROFILE_MORE_DETAIL 0
-#endif
-#ifndef GC_PROFILE_DETAIL_MEMORY
-# define GC_PROFILE_DETAIL_MEMORY 0
-#endif
-#ifndef GC_ENABLE_LAZY_SWEEP
-# define GC_ENABLE_LAZY_SWEEP   1
-#endif
-#ifndef CALC_EXACT_MALLOC_SIZE
-# define CALC_EXACT_MALLOC_SIZE 0
-#endif
-#if defined(HAVE_MALLOC_USABLE_SIZE) || CALC_EXACT_MALLOC_SIZE > 0
-# ifndef MALLOC_ALLOCATED_SIZE
-#  define MALLOC_ALLOCATED_SIZE 0
-# endif
-#else
-# define MALLOC_ALLOCATED_SIZE 0
-#endif
-#ifndef MALLOC_ALLOCATED_SIZE_CHECK
-# define MALLOC_ALLOCATED_SIZE_CHECK 0
-#endif
-
-#ifndef GC_DEBUG_STRESS_TO_CLASS
-# define GC_DEBUG_STRESS_TO_CLASS RUBY_DEBUG
-#endif
-
-typedef enum {
-    GPR_FLAG_NONE               = 0x000,
-    /* major reason */
-    GPR_FLAG_MAJOR_BY_NOFREE    = 0x001,
-    GPR_FLAG_MAJOR_BY_OLDGEN    = 0x002,
-    GPR_FLAG_MAJOR_BY_SHADY     = 0x004,
-    GPR_FLAG_MAJOR_BY_FORCE     = 0x008,
-#if RGENGC_ESTIMATE_OLDMALLOC
-    GPR_FLAG_MAJOR_BY_OLDMALLOC = 0x020,
-#endif
-    GPR_FLAG_MAJOR_MASK         = 0x0ff,
-
-    /* gc reason */
-    GPR_FLAG_NEWOBJ             = 0x100,
-    GPR_FLAG_MALLOC             = 0x200,
-    GPR_FLAG_METHOD             = 0x400,
-    GPR_FLAG_CAPI               = 0x800,
-    GPR_FLAG_STRESS            = 0x1000,
-
-    /* others */
-    GPR_FLAG_IMMEDIATE_SWEEP   = 0x2000,
-    GPR_FLAG_HAVE_FINALIZE     = 0x4000,
-    GPR_FLAG_IMMEDIATE_MARK    = 0x8000,
-    GPR_FLAG_FULL_MARK        = 0x10000,
-    GPR_FLAG_COMPACT          = 0x20000,
-
-    GPR_DEFAULT_REASON =
-        (GPR_FLAG_FULL_MARK | GPR_FLAG_IMMEDIATE_MARK |
-         GPR_FLAG_IMMEDIATE_SWEEP | GPR_FLAG_CAPI),
-} gc_profile_record_flag;
-
-typedef struct gc_profile_record {
-    unsigned int flags;
-
-    double gc_time;
-    double gc_invoke_time;
-
-    size_t heap_total_objects;
-    size_t heap_use_size;
-    size_t heap_total_size;
-    size_t moved_objects;
-
-#if GC_PROFILE_MORE_DETAIL
-    double gc_mark_time;
-    double gc_sweep_time;
-
-    size_t heap_use_pages;
-    size_t heap_live_objects;
-    size_t heap_free_objects;
-
-    size_t allocate_increase;
-    size_t allocate_limit;
-
-    double prepare_time;
-    size_t removing_objects;
-    size_t empty_objects;
-#if GC_PROFILE_DETAIL_MEMORY
-    long maxrss;
-    long minflt;
-    long majflt;
-#endif
-#endif
-#if MALLOC_ALLOCATED_SIZE
-    size_t allocated_size;
-#endif
-
-#if RGENGC_PROFILE > 0
-    size_t old_objects;
-    size_t remembered_normal_objects;
-    size_t remembered_shady_objects;
-#endif
-} gc_profile_record;
-
-struct RMoved {
-    VALUE flags;
-    VALUE dummy;
-    VALUE destination;
-    uint32_t original_shape_id;
-};
-
-#define RMOVED(obj) ((struct RMoved *)(obj))
-
-typedef uintptr_t bits_t;
-enum {
-    BITS_SIZE = sizeof(bits_t),
-    BITS_BITLENGTH = ( BITS_SIZE * CHAR_BIT )
-};
-
-struct heap_page_header {
-    struct heap_page *page;
-};
-
-struct heap_page_body {
-    struct heap_page_header header;
-    /* char gap[];      */
-    /* RVALUE values[]; */
-};
-
-#define STACK_CHUNK_SIZE 500
-
-typedef struct stack_chunk {
-    VALUE data[STACK_CHUNK_SIZE];
-    struct stack_chunk *next;
-} stack_chunk_t;
-
-typedef struct mark_stack {
-    stack_chunk_t *chunk;
-    stack_chunk_t *cache;
-    int index;
-    int limit;
-    size_t cache_size;
-    size_t unused_cache_size;
-} mark_stack_t;
-
-typedef int (*gc_compact_compare_func)(const void *l, const void *r, void *d);
-
-typedef struct rb_heap_struct {
-    short slot_size;
-
-    /* Basic statistics */
-    size_t total_allocated_pages;
-    size_t force_major_gc_count;
-    size_t force_incremental_marking_finish_count;
-    size_t total_allocated_objects;
-    size_t total_freed_objects;
-    size_t final_slots_count;
-
-    /* Sweeping statistics */
-    size_t freed_slots;
-    size_t empty_slots;
-
-    struct heap_page *free_pages;
-    struct ccan_list_head pages;
-    struct heap_page *sweeping_page; /* iterator for .pages */
-    struct heap_page *compact_cursor;
-    uintptr_t compact_cursor_index;
-    struct heap_page *pooled_pages;
-    size_t total_pages;      /* total page count in a heap */
-    size_t total_slots;      /* total slot count (about total_pages * HEAP_PAGE_OBJ_LIMIT) */
-
-} rb_heap_t;
-
-enum {
-    gc_stress_no_major,
-    gc_stress_no_immediate_sweep,
-    gc_stress_full_mark_after_malloc,
-    gc_stress_max
-};
-
-enum gc_mode {
-    gc_mode_none,
-    gc_mode_marking,
-    gc_mode_sweeping,
-    gc_mode_compacting,
-};
-
-typedef struct rb_objspace {
-    struct {
-        size_t limit;
-        size_t increase;
-#if MALLOC_ALLOCATED_SIZE
-        size_t allocated_size;
-        size_t allocations;
-#endif
-    } malloc_params;
-
-    struct rb_gc_config {
-        bool full_mark;
-    } gc_config;
-
-    struct {
-        unsigned int mode : 2;
-        unsigned int immediate_sweep : 1;
-        unsigned int dont_gc : 1;
-        unsigned int dont_incremental : 1;
-        unsigned int during_gc : 1;
-        unsigned int during_compacting : 1;
-        unsigned int during_reference_updating : 1;
-        unsigned int gc_stressful: 1;
-        unsigned int has_newobj_hook: 1;
-        unsigned int during_minor_gc : 1;
-        unsigned int during_incremental_marking : 1;
-        unsigned int measure_gc : 1;
-    } flags;
-
-    rb_event_flag_t hook_events;
-    unsigned long long next_object_id;
-
-    rb_heap_t heaps[HEAP_COUNT];
-    size_t empty_pages_count;
-    struct heap_page *empty_pages;
-
-    struct {
-        rb_atomic_t finalizing;
-    } atomic_flags;
-
-    mark_stack_t mark_stack;
-    size_t marked_slots;
-
-    struct {
-        rb_darray(struct heap_page *) sorted;
-
-        size_t allocated_pages;
-        size_t freed_pages;
-        uintptr_t range[2];
-        size_t freeable_pages;
-
-        size_t allocatable_slots;
-
-        /* final */
-        VALUE deferred_final;
-    } heap_pages;
-
-    st_table *finalizer_table;
-
-    struct {
-        int run;
-        unsigned int latest_gc_info;
-        gc_profile_record *records;
-        gc_profile_record *current_record;
-        size_t next_index;
-        size_t size;
-
-#if GC_PROFILE_MORE_DETAIL
-        double prepare_time;
-#endif
-        double invoke_time;
-
-        size_t minor_gc_count;
-        size_t major_gc_count;
-        size_t compact_count;
-        size_t read_barrier_faults;
-#if RGENGC_PROFILE > 0
-        size_t total_generated_normal_object_count;
-        size_t total_generated_shady_object_count;
-        size_t total_shade_operation_count;
-        size_t total_promoted_count;
-        size_t total_remembered_normal_object_count;
-        size_t total_remembered_shady_object_count;
-
-#if RGENGC_PROFILE >= 2
-        size_t generated_normal_object_count_types[RUBY_T_MASK];
-        size_t generated_shady_object_count_types[RUBY_T_MASK];
-        size_t shade_operation_count_types[RUBY_T_MASK];
-        size_t promoted_types[RUBY_T_MASK];
-        size_t remembered_normal_object_count_types[RUBY_T_MASK];
-        size_t remembered_shady_object_count_types[RUBY_T_MASK];
-#endif
-#endif /* RGENGC_PROFILE */
-
-        /* temporary profiling space */
-        double gc_sweep_start_time;
-        size_t total_allocated_objects_at_gc_start;
-        size_t heap_used_at_gc_start;
-
-        /* basic statistics */
-        size_t count;
-        unsigned long long marking_time_ns;
-        struct timespec marking_start_time;
-        unsigned long long sweeping_time_ns;
-        struct timespec sweeping_start_time;
-
-        /* Weak references */
-        size_t weak_references_count;
-        size_t retained_weak_references_count;
-    } profile;
-
-    VALUE gc_stress_mode;
-
-    struct {
-        VALUE parent_object;
-        int need_major_gc;
-        size_t last_major_gc;
-        size_t uncollectible_wb_unprotected_objects;
-        size_t uncollectible_wb_unprotected_objects_limit;
-        size_t old_objects;
-        size_t old_objects_limit;
-
-#if RGENGC_ESTIMATE_OLDMALLOC
-        size_t oldmalloc_increase;
-        size_t oldmalloc_increase_limit;
-#endif
-
-#if RGENGC_CHECK_MODE >= 2
-        struct st_table *allrefs_table;
-        size_t error_count;
-#endif
-    } rgengc;
-
-    struct {
-        size_t considered_count_table[T_MASK];
-        size_t moved_count_table[T_MASK];
-        size_t moved_up_count_table[T_MASK];
-        size_t moved_down_count_table[T_MASK];
-        size_t total_moved;
-
-        /* This function will be used, if set, to sort the heap prior to compaction */
-        gc_compact_compare_func compare_func;
-    } rcompactor;
-
-    struct {
-        size_t pooled_slots;
-        size_t step_slots;
-    } rincgc;
-
-    st_table *id_to_obj_tbl;
-    st_table *obj_to_id_tbl;
-
-#if GC_DEBUG_STRESS_TO_CLASS
-    VALUE stress_to_class;
-#endif
-
-    rb_darray(VALUE *) weak_references;
-    rb_postponed_job_handle_t finalize_deferred_pjob;
-
-    unsigned long live_ractor_cache_count;
-} rb_objspace_t;
-
-#ifndef HEAP_PAGE_ALIGN_LOG
-/* default tiny heap size: 64KiB */
-#define HEAP_PAGE_ALIGN_LOG 16
-#endif
-
-#if RACTOR_CHECK_MODE || GC_DEBUG
-struct rvalue_overhead {
-# if RACTOR_CHECK_MODE
-    uint32_t _ractor_belonging_id;
-# endif
-# if GC_DEBUG
-    const char *file;
-    int line;
-# endif
-};
-
-// Make sure that RVALUE_OVERHEAD aligns to sizeof(VALUE)
-# define RVALUE_OVERHEAD (sizeof(struct { \
-    union { \
-        struct rvalue_overhead overhead; \
-        VALUE value; \
-    }; \
-}))
-size_t rb_gc_impl_obj_slot_size(VALUE obj);
-# define GET_RVALUE_OVERHEAD(obj) ((struct rvalue_overhead *)((uintptr_t)obj + rb_gc_impl_obj_slot_size(obj)))
-#else
-# define RVALUE_OVERHEAD 0
-#endif
-
-#define BASE_SLOT_SIZE (sizeof(struct RBasic) + sizeof(VALUE[RBIMPL_RVALUE_EMBED_LEN_MAX]) + RVALUE_OVERHEAD)
-
-#ifndef MAX
-# define MAX(a, b) (((a) > (b)) ? (a) : (b))
-#endif
-#ifndef MIN
-# define MIN(a, b) (((a) < (b)) ? (a) : (b))
-#endif
-#define roomof(x, y) (((x) + (y) - 1) / (y))
-#define CEILDIV(i, mod) roomof(i, mod)
-enum {
-    HEAP_PAGE_ALIGN = (1UL << HEAP_PAGE_ALIGN_LOG),
-    HEAP_PAGE_ALIGN_MASK = (~(~0UL << HEAP_PAGE_ALIGN_LOG)),
-    HEAP_PAGE_SIZE = HEAP_PAGE_ALIGN,
-    HEAP_PAGE_OBJ_LIMIT = (unsigned int)((HEAP_PAGE_SIZE - sizeof(struct heap_page_header)) / BASE_SLOT_SIZE),
-    HEAP_PAGE_BITMAP_LIMIT = CEILDIV(CEILDIV(HEAP_PAGE_SIZE, BASE_SLOT_SIZE), BITS_BITLENGTH),
-    HEAP_PAGE_BITMAP_SIZE = (BITS_SIZE * HEAP_PAGE_BITMAP_LIMIT),
-};
-#define HEAP_PAGE_ALIGN (1 << HEAP_PAGE_ALIGN_LOG)
-#define HEAP_PAGE_SIZE HEAP_PAGE_ALIGN
-
-#if !defined(INCREMENTAL_MARK_STEP_ALLOCATIONS)
-# define INCREMENTAL_MARK_STEP_ALLOCATIONS 500
-#endif
-
-#undef INIT_HEAP_PAGE_ALLOC_USE_MMAP
-/* Must define either HEAP_PAGE_ALLOC_USE_MMAP or
- * INIT_HEAP_PAGE_ALLOC_USE_MMAP. */
-
-#ifndef HAVE_MMAP
-/* We can't use mmap of course, if it is not available. */
-static const bool HEAP_PAGE_ALLOC_USE_MMAP = false;
-
-#elif defined(__wasm__)
-/* wasmtime does not have proper support for mmap.
- * See https://github.com/bytecodealliance/wasmtime/blob/main/docs/WASI-rationale.md#why-no-mmap-and-friends
- */
-static const bool HEAP_PAGE_ALLOC_USE_MMAP = false;
-
-#elif HAVE_CONST_PAGE_SIZE
-/* If we have the PAGE_SIZE and it is a constant, then we can directly use it. */
-static const bool HEAP_PAGE_ALLOC_USE_MMAP = (PAGE_SIZE <= HEAP_PAGE_SIZE);
-
-#elif defined(PAGE_MAX_SIZE) && (PAGE_MAX_SIZE <= HEAP_PAGE_SIZE)
-/* If we can use the maximum page size. */
-static const bool HEAP_PAGE_ALLOC_USE_MMAP = true;
-
-#elif defined(PAGE_SIZE)
-/* If the PAGE_SIZE macro can be used dynamically. */
-# define INIT_HEAP_PAGE_ALLOC_USE_MMAP (PAGE_SIZE <= HEAP_PAGE_SIZE)
-
-#elif defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
-/* If we can use sysconf to determine the page size. */
-# define INIT_HEAP_PAGE_ALLOC_USE_MMAP (sysconf(_SC_PAGE_SIZE) <= HEAP_PAGE_SIZE)
-
-#else
-/* Otherwise we can't determine the system page size, so don't use mmap. */
-static const bool HEAP_PAGE_ALLOC_USE_MMAP = false;
-#endif
-
-#ifdef INIT_HEAP_PAGE_ALLOC_USE_MMAP
-/* We can determine the system page size at runtime. */
-# define HEAP_PAGE_ALLOC_USE_MMAP (heap_page_alloc_use_mmap != false)
-
-static bool heap_page_alloc_use_mmap;
-#endif
-
-#define RVALUE_AGE_BIT_COUNT 2
-#define RVALUE_AGE_BIT_MASK (((bits_t)1 << RVALUE_AGE_BIT_COUNT) - 1)
-#define RVALUE_OLD_AGE   3
-
-struct free_slot {
-    VALUE flags;		/* always 0 for freed obj */
-    struct free_slot *next;
-};
-
-struct heap_page {
-    unsigned short slot_size;
-    unsigned short total_slots;
-    unsigned short free_slots;
-    unsigned short final_slots;
-    unsigned short pinned_slots;
-    struct {
-        unsigned int before_sweep : 1;
-        unsigned int has_remembered_objects : 1;
-        unsigned int has_uncollectible_wb_unprotected_objects : 1;
-    } flags;
-
-    rb_heap_t *heap;
-
-    struct heap_page *free_next;
-    struct heap_page_body *body;
-    uintptr_t start;
-    struct free_slot *freelist;
-    struct ccan_list_node page_node;
-
-    bits_t wb_unprotected_bits[HEAP_PAGE_BITMAP_LIMIT];
-    /* the following three bitmaps are cleared at the beginning of full GC */
-    bits_t mark_bits[HEAP_PAGE_BITMAP_LIMIT];
-    bits_t uncollectible_bits[HEAP_PAGE_BITMAP_LIMIT];
-    bits_t marking_bits[HEAP_PAGE_BITMAP_LIMIT];
-
-    bits_t remembered_bits[HEAP_PAGE_BITMAP_LIMIT];
-
-    /* If set, the object is not movable */
-    bits_t pinned_bits[HEAP_PAGE_BITMAP_LIMIT];
-    bits_t age_bits[HEAP_PAGE_BITMAP_LIMIT * RVALUE_AGE_BIT_COUNT];
-};
-
-/*
- * When asan is enabled, this will prohibit writing to the freelist until it is unlocked
- */
-static void
-asan_lock_freelist(struct heap_page *page)
-{
-    asan_poison_memory_region(&page->freelist, sizeof(struct free_list *));
-}
-
-/*
- * When asan is enabled, this will enable the ability to write to the freelist
- */
-static void
-asan_unlock_freelist(struct heap_page *page)
-{
-    asan_unpoison_memory_region(&page->freelist, sizeof(struct free_list *), false);
-}
-
-static inline bool
-heap_page_in_global_empty_pages_pool(rb_objspace_t *objspace, struct heap_page *page)
-{
-    if (page->total_slots == 0) {
-        GC_ASSERT(page->start == 0);
-        GC_ASSERT(page->slot_size == 0);
-        GC_ASSERT(page->heap == NULL);
-        GC_ASSERT(page->free_slots == 0);
-        asan_unpoisoning_memory_region(&page->freelist, sizeof(&page->freelist)) {
-            GC_ASSERT(page->freelist == NULL);
-        }
-
-        return true;
-    }
-    else {
-        GC_ASSERT(page->start != 0);
-        GC_ASSERT(page->slot_size != 0);
-        GC_ASSERT(page->heap != NULL);
-
-        return false;
-    }
-}
-
-#define GET_PAGE_BODY(x)   ((struct heap_page_body *)((bits_t)(x) & ~(HEAP_PAGE_ALIGN_MASK)))
-#define GET_PAGE_HEADER(x) (&GET_PAGE_BODY(x)->header)
-#define GET_HEAP_PAGE(x)   (GET_PAGE_HEADER(x)->page)
-
-#define NUM_IN_PAGE(p)   (((bits_t)(p) & HEAP_PAGE_ALIGN_MASK) / BASE_SLOT_SIZE)
-#define BITMAP_INDEX(p)  (NUM_IN_PAGE(p) / BITS_BITLENGTH )
-#define BITMAP_OFFSET(p) (NUM_IN_PAGE(p) & (BITS_BITLENGTH-1))
-#define BITMAP_BIT(p)    ((bits_t)1 << BITMAP_OFFSET(p))
-
-/* Bitmap Operations */
-#define MARKED_IN_BITMAP(bits, p)    ((bits)[BITMAP_INDEX(p)] & BITMAP_BIT(p))
-#define MARK_IN_BITMAP(bits, p)      ((bits)[BITMAP_INDEX(p)] = (bits)[BITMAP_INDEX(p)] | BITMAP_BIT(p))
-#define CLEAR_IN_BITMAP(bits, p)     ((bits)[BITMAP_INDEX(p)] = (bits)[BITMAP_INDEX(p)] & ~BITMAP_BIT(p))
-
-/* getting bitmap */
-#define GET_HEAP_MARK_BITS(x)           (&GET_HEAP_PAGE(x)->mark_bits[0])
-#define GET_HEAP_PINNED_BITS(x)         (&GET_HEAP_PAGE(x)->pinned_bits[0])
-#define GET_HEAP_UNCOLLECTIBLE_BITS(x)  (&GET_HEAP_PAGE(x)->uncollectible_bits[0])
-#define GET_HEAP_WB_UNPROTECTED_BITS(x) (&GET_HEAP_PAGE(x)->wb_unprotected_bits[0])
-#define GET_HEAP_MARKING_BITS(x)        (&GET_HEAP_PAGE(x)->marking_bits[0])
-
-#define GC_SWEEP_PAGES_FREEABLE_PER_STEP 3
-
-#define RVALUE_AGE_BITMAP_INDEX(n)  (NUM_IN_PAGE(n) / (BITS_BITLENGTH / RVALUE_AGE_BIT_COUNT))
-#define RVALUE_AGE_BITMAP_OFFSET(n) ((NUM_IN_PAGE(n) % (BITS_BITLENGTH / RVALUE_AGE_BIT_COUNT)) * RVALUE_AGE_BIT_COUNT)
-
-static int
-RVALUE_AGE_GET(VALUE obj)
-{
-    bits_t *age_bits = GET_HEAP_PAGE(obj)->age_bits;
-    return (int)(age_bits[RVALUE_AGE_BITMAP_INDEX(obj)] >> RVALUE_AGE_BITMAP_OFFSET(obj)) & RVALUE_AGE_BIT_MASK;
-}
-
-static void
-RVALUE_AGE_SET(VALUE obj, int age)
-{
-    RUBY_ASSERT(age <= RVALUE_OLD_AGE);
-    bits_t *age_bits = GET_HEAP_PAGE(obj)->age_bits;
-    // clear the bits
-    age_bits[RVALUE_AGE_BITMAP_INDEX(obj)] &= ~(RVALUE_AGE_BIT_MASK << (RVALUE_AGE_BITMAP_OFFSET(obj)));
-    // shift the correct value in
-    age_bits[RVALUE_AGE_BITMAP_INDEX(obj)] |= ((bits_t)age << RVALUE_AGE_BITMAP_OFFSET(obj));
-    if (age == RVALUE_OLD_AGE) {
-        RB_FL_SET_RAW(obj, RUBY_FL_PROMOTED);
-    }
-    else {
-        RB_FL_UNSET_RAW(obj, RUBY_FL_PROMOTED);
-    }
-}
-
-#define malloc_limit		objspace->malloc_params.limit
-#define malloc_increase 	objspace->malloc_params.increase
-#define malloc_allocated_size 	objspace->malloc_params.allocated_size
-#define heap_pages_lomem	objspace->heap_pages.range[0]
-#define heap_pages_himem	objspace->heap_pages.range[1]
-#define heap_pages_freeable_pages	objspace->heap_pages.freeable_pages
-#define heap_pages_deferred_final	objspace->heap_pages.deferred_final
-#define heaps              objspace->heaps
-#define during_gc		objspace->flags.during_gc
-#define finalizing		objspace->atomic_flags.finalizing
-#define finalizer_table 	objspace->finalizer_table
-#define ruby_gc_stressful	objspace->flags.gc_stressful
-#define ruby_gc_stress_mode     objspace->gc_stress_mode
-#if GC_DEBUG_STRESS_TO_CLASS
-#define stress_to_class         objspace->stress_to_class
-#define set_stress_to_class(c)  (stress_to_class = (c))
-#else
-#define stress_to_class         (objspace, 0)
-#define set_stress_to_class(c)  (objspace, (c))
-#endif
-
-#if 0
-#define dont_gc_on()          (fprintf(stderr, "dont_gc_on@%s:%d\n",      __FILE__, __LINE__), objspace->flags.dont_gc = 1)
-#define dont_gc_off()         (fprintf(stderr, "dont_gc_off@%s:%d\n",     __FILE__, __LINE__), objspace->flags.dont_gc = 0)
-#define dont_gc_set(b)        (fprintf(stderr, "dont_gc_set(%d)@%s:%d\n", __FILE__, __LINE__), objspace->flags.dont_gc = (int)(b))
-#define dont_gc_val()         (objspace->flags.dont_gc)
-#else
-#define dont_gc_on()          (objspace->flags.dont_gc = 1)
-#define dont_gc_off()         (objspace->flags.dont_gc = 0)
-#define dont_gc_set(b)        (objspace->flags.dont_gc = (int)(b))
-#define dont_gc_val()         (objspace->flags.dont_gc)
-#endif
-
-#define gc_config_full_mark_set(b) (objspace->gc_config.full_mark = (int)(b))
-#define gc_config_full_mark_val    (objspace->gc_config.full_mark)
-
-#ifndef DURING_GC_COULD_MALLOC_REGION_START
-# define DURING_GC_COULD_MALLOC_REGION_START() \
-    assert(rb_during_gc()); \
-    bool _prev_enabled = rb_gc_impl_gc_enabled_p(objspace); \
-    rb_gc_impl_gc_disable(objspace, false)
-#endif
-
-#ifndef DURING_GC_COULD_MALLOC_REGION_END
-# define DURING_GC_COULD_MALLOC_REGION_END() \
-    if (_prev_enabled) rb_gc_impl_gc_enable(objspace)
-#endif
-
-static inline enum gc_mode
-gc_mode_verify(enum gc_mode mode)
-{
-#if RGENGC_CHECK_MODE > 0
-    switch (mode) {
-      case gc_mode_none:
-      case gc_mode_marking:
-      case gc_mode_sweeping:
-      case gc_mode_compacting:
-        break;
-      default:
-        rb_bug("gc_mode_verify: unreachable (%d)", (int)mode);
-    }
-#endif
-    return mode;
-}
-
-static inline bool
-has_sweeping_pages(rb_objspace_t *objspace)
-{
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        if ((&heaps[i])->sweeping_page) {
-            return TRUE;
-        }
-    }
-    return FALSE;
-}
-
-static inline size_t
-heap_eden_total_pages(rb_objspace_t *objspace)
-{
-    size_t count = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        count += (&heaps[i])->total_pages;
-    }
-    return count;
-}
-
-static inline size_t
-total_allocated_objects(rb_objspace_t *objspace)
-{
-    size_t count = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        count += heap->total_allocated_objects;
-    }
-    return count;
-}
-
-static inline size_t
-total_freed_objects(rb_objspace_t *objspace)
-{
-    size_t count = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        count += heap->total_freed_objects;
-    }
-    return count;
-}
-
-static inline size_t
-total_final_slots_count(rb_objspace_t *objspace)
-{
-    size_t count = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        count += heap->final_slots_count;
-    }
-    return count;
-}
-
-#define gc_mode(objspace)                gc_mode_verify((enum gc_mode)(objspace)->flags.mode)
-#define gc_mode_set(objspace, m)         ((objspace)->flags.mode = (unsigned int)gc_mode_verify(m))
-#define gc_needs_major_flags objspace->rgengc.need_major_gc
-
-#define is_marking(objspace)             (gc_mode(objspace) == gc_mode_marking)
-#define is_sweeping(objspace)            (gc_mode(objspace) == gc_mode_sweeping)
-#define is_full_marking(objspace)        ((objspace)->flags.during_minor_gc == FALSE)
-#define is_incremental_marking(objspace) ((objspace)->flags.during_incremental_marking != FALSE)
-#define will_be_incremental_marking(objspace) ((objspace)->rgengc.need_major_gc != GPR_FLAG_NONE)
-#define GC_INCREMENTAL_SWEEP_SLOT_COUNT 2048
-#define GC_INCREMENTAL_SWEEP_POOL_SLOT_COUNT 1024
-#define is_lazy_sweeping(objspace)           (GC_ENABLE_LAZY_SWEEP && has_sweeping_pages(objspace))
-
-#if SIZEOF_LONG == SIZEOF_VOIDP
-# define obj_id_to_ref(objid) ((objid) ^ FIXNUM_FLAG) /* unset FIXNUM_FLAG */
-#elif SIZEOF_LONG_LONG == SIZEOF_VOIDP
-# define obj_id_to_ref(objid) (FIXNUM_P(objid) ? \
-   ((objid) ^ FIXNUM_FLAG) : (NUM2PTR(objid) << 1))
-#else
-# error not supported
-#endif
-
-struct RZombie {
-    struct RBasic basic;
-    VALUE next;
-    void (*dfree)(void *);
-    void *data;
-};
-
-#define RZOMBIE(o) ((struct RZombie *)(o))
-
-int ruby_disable_gc = 0;
-int ruby_enable_autocompact = 0;
-#if RGENGC_CHECK_MODE
-gc_compact_compare_func ruby_autocompact_compare_func;
-#endif
-
-static void init_mark_stack(mark_stack_t *stack);
-static int garbage_collect(rb_objspace_t *, unsigned int reason);
-
-static int  gc_start(rb_objspace_t *objspace, unsigned int reason);
-static void gc_rest(rb_objspace_t *objspace);
-
-enum gc_enter_event {
-    gc_enter_event_start,
-    gc_enter_event_continue,
-    gc_enter_event_rest,
-    gc_enter_event_finalizer,
-};
-
-static inline void gc_enter(rb_objspace_t *objspace, enum gc_enter_event event, unsigned int *lock_lev);
-static inline void gc_exit(rb_objspace_t *objspace, enum gc_enter_event event, unsigned int *lock_lev);
-static void gc_marking_enter(rb_objspace_t *objspace);
-static void gc_marking_exit(rb_objspace_t *objspace);
-static void gc_sweeping_enter(rb_objspace_t *objspace);
-static void gc_sweeping_exit(rb_objspace_t *objspace);
-static bool gc_marks_continue(rb_objspace_t *objspace, rb_heap_t *heap);
-
-static void gc_sweep(rb_objspace_t *objspace);
-static void gc_sweep_finish_heap(rb_objspace_t *objspace, rb_heap_t *heap);
-static void gc_sweep_continue(rb_objspace_t *objspace, rb_heap_t *heap);
-
-static inline void gc_mark(rb_objspace_t *objspace, VALUE ptr);
-static inline void gc_pin(rb_objspace_t *objspace, VALUE ptr);
-static inline void gc_mark_and_pin(rb_objspace_t *objspace, VALUE ptr);
-
-static int gc_mark_stacked_objects_incremental(rb_objspace_t *, size_t count);
-NO_SANITIZE("memory", static inline bool is_pointer_to_heap(rb_objspace_t *objspace, const void *ptr));
-
-static void gc_verify_internal_consistency(void *objspace_ptr);
-
-static double getrusage_time(void);
-static inline void gc_prof_setup_new_record(rb_objspace_t *objspace, unsigned int reason);
-static inline void gc_prof_timer_start(rb_objspace_t *);
-static inline void gc_prof_timer_stop(rb_objspace_t *);
-static inline void gc_prof_mark_timer_start(rb_objspace_t *);
-static inline void gc_prof_mark_timer_stop(rb_objspace_t *);
-static inline void gc_prof_sweep_timer_start(rb_objspace_t *);
-static inline void gc_prof_sweep_timer_stop(rb_objspace_t *);
-static inline void gc_prof_set_malloc_info(rb_objspace_t *);
-static inline void gc_prof_set_heap_info(rb_objspace_t *);
-
-#define gc_prof_record(objspace) (objspace)->profile.current_record
-#define gc_prof_enabled(objspace) ((objspace)->profile.run && (objspace)->profile.current_record)
-
-#ifdef HAVE_VA_ARGS_MACRO
-# define gc_report(level, objspace, ...) \
-    if (!RGENGC_DEBUG_ENABLED(level)) {} else gc_report_body(level, objspace, __VA_ARGS__)
-#else
-# define gc_report if (!RGENGC_DEBUG_ENABLED(0)) {} else gc_report_body
-#endif
-PRINTF_ARGS(static void gc_report_body(int level, rb_objspace_t *objspace, const char *fmt, ...), 3, 4);
-
-static void gc_finalize_deferred(void *dmy);
-
-#if USE_TICK_T
-
-/* the following code is only for internal tuning. */
-
-/* Source code to use RDTSC is quoted and modified from
- * https://www.mcs.anl.gov/~kazutomo/rdtsc.html
- * written by Kazutomo Yoshii <[email protected]>
- */
-
-#if defined(__GNUC__) && defined(__i386__)
-typedef unsigned long long tick_t;
-#define PRItick "llu"
-static inline tick_t
-tick(void)
-{
-    unsigned long long int x;
-    __asm__ __volatile__ ("rdtsc" : "=A" (x));
-    return x;
-}
-
-#elif defined(__GNUC__) && defined(__x86_64__)
-typedef unsigned long long tick_t;
-#define PRItick "llu"
-
-static __inline__ tick_t
-tick(void)
-{
-    unsigned long hi, lo;
-    __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
-    return ((unsigned long long)lo)|( ((unsigned long long)hi)<<32);
-}
-
-#elif defined(__powerpc64__) && (GCC_VERSION_SINCE(4,8,0) || defined(__clang__))
-typedef unsigned long long tick_t;
-#define PRItick "llu"
-
-static __inline__ tick_t
-tick(void)
-{
-    unsigned long long val = __builtin_ppc_get_timebase();
-    return val;
-}
-
-/* Implementation for macOS PPC by @nobu
- * See: https://github.com/ruby/ruby/pull/5975#discussion_r890045558
- */
-#elif defined(__POWERPC__) && defined(__APPLE__)
-typedef unsigned long long tick_t;
-#define PRItick "llu"
-
-static __inline__ tick_t
-tick(void)
-{
-    unsigned long int upper, lower, tmp;
-    # define mftbu(r) __asm__ volatile("mftbu   %0" : "=r"(r))
-    # define mftb(r)  __asm__ volatile("mftb    %0" : "=r"(r))
-        do {
-            mftbu(upper);
-            mftb(lower);
-            mftbu(tmp);
-        } while (tmp != upper);
-    return ((tick_t)upper << 32) | lower;
-}
-
-#elif defined(__aarch64__) &&  defined(__GNUC__)
-typedef unsigned long tick_t;
-#define PRItick "lu"
-
-static __inline__ tick_t
-tick(void)
-{
-    unsigned long val;
-    __asm__ __volatile__ ("mrs %0, cntvct_el0" : "=r" (val));
-    return val;
-}
-
-
-#elif defined(_WIN32) && defined(_MSC_VER)
-#include <intrin.h>
-typedef unsigned __int64 tick_t;
-#define PRItick "llu"
-
-static inline tick_t
-tick(void)
-{
-    return __rdtsc();
-}
-
-#else /* use clock */
-typedef clock_t tick_t;
-#define PRItick "llu"
-
-static inline tick_t
-tick(void)
-{
-    return clock();
-}
-#endif /* TSC */
-#else /* USE_TICK_T */
-#define MEASURE_LINE(expr) expr
-#endif /* USE_TICK_T */
-
-static inline VALUE check_rvalue_consistency(rb_objspace_t *objspace, const VALUE obj);
-
-#define RVALUE_MARKED_BITMAP(obj)         MARKED_IN_BITMAP(GET_HEAP_MARK_BITS(obj), (obj))
-#define RVALUE_WB_UNPROTECTED_BITMAP(obj) MARKED_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(obj), (obj))
-#define RVALUE_MARKING_BITMAP(obj)        MARKED_IN_BITMAP(GET_HEAP_MARKING_BITS(obj), (obj))
-#define RVALUE_UNCOLLECTIBLE_BITMAP(obj)  MARKED_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(obj), (obj))
-#define RVALUE_PINNED_BITMAP(obj)         MARKED_IN_BITMAP(GET_HEAP_PINNED_BITS(obj), (obj))
-
-static inline int
-RVALUE_MARKED(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return RVALUE_MARKED_BITMAP(obj) != 0;
-}
-
-static inline int
-RVALUE_PINNED(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return RVALUE_PINNED_BITMAP(obj) != 0;
-}
-
-static inline int
-RVALUE_WB_UNPROTECTED(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return RVALUE_WB_UNPROTECTED_BITMAP(obj) != 0;
-}
-
-static inline int
-RVALUE_MARKING(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return RVALUE_MARKING_BITMAP(obj) != 0;
-}
-
-static inline int
-RVALUE_REMEMBERED(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return MARKED_IN_BITMAP(GET_HEAP_PAGE(obj)->remembered_bits, obj) != 0;
-}
-
-static inline int
-RVALUE_UNCOLLECTIBLE(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    return RVALUE_UNCOLLECTIBLE_BITMAP(obj) != 0;
-}
-
-#define RVALUE_PAGE_WB_UNPROTECTED(page, obj) MARKED_IN_BITMAP((page)->wb_unprotected_bits, (obj))
-#define RVALUE_PAGE_UNCOLLECTIBLE(page, obj)  MARKED_IN_BITMAP((page)->uncollectible_bits, (obj))
-#define RVALUE_PAGE_MARKING(page, obj)        MARKED_IN_BITMAP((page)->marking_bits, (obj))
-
-static int rgengc_remember(rb_objspace_t *objspace, VALUE obj);
-static void rgengc_mark_and_rememberset_clear(rb_objspace_t *objspace, rb_heap_t *heap);
-static void rgengc_rememberset_mark(rb_objspace_t *objspace, rb_heap_t *heap);
-
-static int
-check_rvalue_consistency_force(rb_objspace_t *objspace, const VALUE obj, int terminate)
-{
-    int err = 0;
-
-    int lev = rb_gc_vm_lock_no_barrier();
-    {
-        if (SPECIAL_CONST_P(obj)) {
-            fprintf(stderr, "check_rvalue_consistency: %p is a special const.\n", (void *)obj);
-            err++;
-        }
-        else if (!is_pointer_to_heap(objspace, (void *)obj)) {
-            struct heap_page *empty_page = objspace->empty_pages;
-            while (empty_page) {
-                if ((uintptr_t)empty_page->body <= (uintptr_t)obj &&
-                        (uintptr_t)obj < (uintptr_t)empty_page->body + HEAP_PAGE_SIZE) {
-                    GC_ASSERT(heap_page_in_global_empty_pages_pool(objspace, empty_page));
-                    fprintf(stderr, "check_rvalue_consistency: %p is in an empty page (%p).\n",
-                            (void *)obj, (void *)empty_page);
-                    err++;
-                    goto skip;
-                }
-            }
-            fprintf(stderr, "check_rvalue_consistency: %p is not a Ruby object.\n", (void *)obj);
-            err++;
-          skip:
-            ;
-        }
-        else {
-            const int wb_unprotected_bit = RVALUE_WB_UNPROTECTED_BITMAP(obj) != 0;
-            const int uncollectible_bit = RVALUE_UNCOLLECTIBLE_BITMAP(obj) != 0;
-            const int mark_bit = RVALUE_MARKED_BITMAP(obj) != 0;
-            const int marking_bit = RVALUE_MARKING_BITMAP(obj) != 0;
-            const int remembered_bit = MARKED_IN_BITMAP(GET_HEAP_PAGE(obj)->remembered_bits, obj) != 0;
-            const int age = RVALUE_AGE_GET((VALUE)obj);
-
-            if (heap_page_in_global_empty_pages_pool(objspace, GET_HEAP_PAGE(obj))) {
-                fprintf(stderr, "check_rvalue_consistency: %s is in tomb page.\n", rb_obj_info(obj));
-                err++;
-            }
-            if (BUILTIN_TYPE(obj) == T_NONE) {
-                fprintf(stderr, "check_rvalue_consistency: %s is T_NONE.\n", rb_obj_info(obj));
-                err++;
-            }
-            if (BUILTIN_TYPE(obj) == T_ZOMBIE) {
-                fprintf(stderr, "check_rvalue_consistency: %s is T_ZOMBIE.\n", rb_obj_info(obj));
-                err++;
-            }
-
-            if (BUILTIN_TYPE(obj) != T_DATA) {
-                rb_obj_memsize_of((VALUE)obj);
-            }
-
-            /* check generation
-             *
-             * OLD == age == 3 && old-bitmap && mark-bit (except incremental marking)
-             */
-            if (age > 0 && wb_unprotected_bit) {
-                fprintf(stderr, "check_rvalue_consistency: %s is not WB protected, but age is %d > 0.\n", rb_obj_info(obj), age);
-                err++;
-            }
-
-            if (!is_marking(objspace) && uncollectible_bit && !mark_bit) {
-                fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but is not marked while !gc.\n", rb_obj_info(obj));
-                err++;
-            }
-
-            if (!is_full_marking(objspace)) {
-                if (uncollectible_bit && age != RVALUE_OLD_AGE && !wb_unprotected_bit) {
-                    fprintf(stderr, "check_rvalue_consistency: %s is uncollectible, but not old (age: %d) and not WB unprotected.\n",
-                            rb_obj_info(obj), age);
-                    err++;
-                }
-                if (remembered_bit && age != RVALUE_OLD_AGE) {
-                    fprintf(stderr, "check_rvalue_consistency: %s is remembered, but not old (age: %d).\n",
-                            rb_obj_info(obj), age);
-                    err++;
-                }
-            }
-
-            /*
-             * check coloring
-             *
-             *               marking:false marking:true
-             * marked:false  white         *invalid*
-             * marked:true   black         grey
-             */
-            if (is_incremental_marking(objspace) && marking_bit) {
-                if (!is_marking(objspace) && !mark_bit) {
-                    fprintf(stderr, "check_rvalue_consistency: %s is marking, but not marked.\n", rb_obj_info(obj));
-                    err++;
-                }
-            }
-        }
-    }
-    rb_gc_vm_unlock_no_barrier(lev);
-
-    if (err > 0 && terminate) {
-        rb_bug("check_rvalue_consistency_force: there is %d errors.", err);
-    }
-    return err;
-}
-
-#if RGENGC_CHECK_MODE == 0
-static inline VALUE
-check_rvalue_consistency(rb_objspace_t *objspace, const VALUE obj)
-{
-    return obj;
-}
-#else
-static VALUE
-check_rvalue_consistency(rb_objspace_t *objspace, const VALUE obj)
-{
-    check_rvalue_consistency_force(objspace, obj, TRUE);
-    return obj;
-}
-#endif
-
-static inline bool
-gc_object_moved_p(rb_objspace_t *objspace, VALUE obj)
-{
-    if (RB_SPECIAL_CONST_P(obj)) {
-        return FALSE;
-    }
-    else {
-        int ret;
-        asan_unpoisoning_object(obj) {
-            ret = BUILTIN_TYPE(obj) == T_MOVED;
-        }
-        return ret;
-    }
-}
-
-static inline int
-RVALUE_OLD_P(rb_objspace_t *objspace, VALUE obj)
-{
-    GC_ASSERT(!RB_SPECIAL_CONST_P(obj));
-    check_rvalue_consistency(objspace, obj);
-    // Because this will only ever be called on GC controlled objects,
-    // we can use the faster _RAW function here
-    return RB_OBJ_PROMOTED_RAW(obj);
-}
-
-static inline void
-RVALUE_PAGE_OLD_UNCOLLECTIBLE_SET(rb_objspace_t *objspace, struct heap_page *page, VALUE obj)
-{
-    MARK_IN_BITMAP(&page->uncollectible_bits[0], obj);
-    objspace->rgengc.old_objects++;
-
-#if RGENGC_PROFILE >= 2
-    objspace->profile.total_promoted_count++;
-    objspace->profile.promoted_types[BUILTIN_TYPE(obj)]++;
-#endif
-}
-
-static inline void
-RVALUE_OLD_UNCOLLECTIBLE_SET(rb_objspace_t *objspace, VALUE obj)
-{
-    RB_DEBUG_COUNTER_INC(obj_promote);
-    RVALUE_PAGE_OLD_UNCOLLECTIBLE_SET(objspace, GET_HEAP_PAGE(obj), obj);
-}
-
-/* set age to age+1 */
-static inline void
-RVALUE_AGE_INC(rb_objspace_t *objspace, VALUE obj)
-{
-    int age = RVALUE_AGE_GET((VALUE)obj);
-
-    if (RGENGC_CHECK_MODE && age == RVALUE_OLD_AGE) {
-        rb_bug("RVALUE_AGE_INC: can not increment age of OLD object %s.", rb_obj_info(obj));
-    }
-
-    age++;
-    RVALUE_AGE_SET(obj, age);
-
-    if (age == RVALUE_OLD_AGE) {
-        RVALUE_OLD_UNCOLLECTIBLE_SET(objspace, obj);
-    }
-
-    check_rvalue_consistency(objspace, obj);
-}
-
-static inline void
-RVALUE_AGE_SET_CANDIDATE(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    GC_ASSERT(!RVALUE_OLD_P(objspace, obj));
-    RVALUE_AGE_SET(obj, RVALUE_OLD_AGE - 1);
-    check_rvalue_consistency(objspace, obj);
-}
-
-static inline void
-RVALUE_AGE_RESET(VALUE obj)
-{
-    RVALUE_AGE_SET(obj, 0);
-}
-
-static inline void
-RVALUE_DEMOTE(rb_objspace_t *objspace, VALUE obj)
-{
-    check_rvalue_consistency(objspace, obj);
-    GC_ASSERT(RVALUE_OLD_P(objspace, obj));
-
-    if (!is_incremental_marking(objspace) && RVALUE_REMEMBERED(objspace, obj)) {
-        CLEAR_IN_BITMAP(GET_HEAP_PAGE(obj)->remembered_bits, obj);
-    }
-
-    CLEAR_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(obj), obj);
-    RVALUE_AGE_RESET(obj);
-
-    if (RVALUE_MARKED(objspace, obj)) {
-        objspace->rgengc.old_objects--;
-    }
-
-    check_rvalue_consistency(objspace, obj);
-}
-
-static inline int
-RVALUE_BLACK_P(rb_objspace_t *objspace, VALUE obj)
-{
-    return RVALUE_MARKED(objspace, obj) && !RVALUE_MARKING(objspace, obj);
-}
-
-static inline int
-RVALUE_WHITE_P(rb_objspace_t *objspace, VALUE obj)
-{
-    return !RVALUE_MARKED(objspace, obj);
-}
-
-bool
-rb_gc_impl_gc_enabled_p(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    return !dont_gc_val();
-}
-
-void
-rb_gc_impl_gc_enable(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    dont_gc_off();
-}
-
-void
-rb_gc_impl_gc_disable(void *objspace_ptr, bool finish_current_gc)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (finish_current_gc) {
-        gc_rest(objspace);
-    }
-
-    dont_gc_on();
-}
-
-/*
-  --------------------------- ObjectSpace -----------------------------
-*/
-
-static inline void *
-calloc1(size_t n)
-{
-    return calloc(1, n);
-}
-
-void
-rb_gc_impl_set_event_hook(void *objspace_ptr, const rb_event_flag_t event)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    objspace->hook_events = event & RUBY_INTERNAL_EVENT_OBJSPACE_MASK;
-    objspace->flags.has_newobj_hook = !!(objspace->hook_events & RUBY_INTERNAL_EVENT_NEWOBJ);
-}
-
-unsigned long long
-rb_gc_impl_get_total_time(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    unsigned long long marking_time = objspace->profile.marking_time_ns;
-    unsigned long long sweeping_time = objspace->profile.sweeping_time_ns;
-
-    return marking_time + sweeping_time;
-}
-
-void
-rb_gc_impl_set_measure_total_time(void *objspace_ptr, VALUE flag)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    objspace->flags.measure_gc = RTEST(flag) ? TRUE : FALSE;
-}
-
-bool
-rb_gc_impl_get_measure_total_time(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    return objspace->flags.measure_gc;
-}
-
-static size_t
-minimum_slots_for_heap(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    size_t heap_idx = heap - heaps;
-    return gc_params.heap_init_slots[heap_idx];
-}
-
-static int
-object_id_cmp(st_data_t x, st_data_t y)
-{
-    if (RB_TYPE_P(x, T_BIGNUM)) {
-        return !rb_big_eql(x, y);
-    }
-    else {
-        return x != y;
-    }
-}
-
-static st_index_t
-object_id_hash(st_data_t n)
-{
-    return FIX2LONG(rb_hash((VALUE)n));
-}
-
-#define OBJ_ID_INCREMENT (RUBY_IMMEDIATE_MASK + 1)
-#define OBJ_ID_INITIAL (OBJ_ID_INCREMENT)
-
-static const struct st_hash_type object_id_hash_type = {
-    object_id_cmp,
-    object_id_hash,
-};
-
-/* garbage objects will be collected soon. */
-bool
-rb_gc_impl_garbage_object_p(void *objspace_ptr, VALUE ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    bool dead = false;
-
-    asan_unpoisoning_object(ptr) {
-        switch (BUILTIN_TYPE(ptr)) {
-          case T_NONE:
-          case T_MOVED:
-          case T_ZOMBIE:
-            dead = true;
-            break;
-          default:
-            break;
-        }
-    }
-
-    if (dead) return true;
-    return is_lazy_sweeping(objspace) && GET_HEAP_PAGE(ptr)->flags.before_sweep &&
-        !RVALUE_MARKED(objspace, ptr);
-}
-
-VALUE
-rb_gc_impl_object_id_to_ref(void *objspace_ptr, VALUE object_id)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    VALUE obj;
-    if (st_lookup(objspace->id_to_obj_tbl, object_id, &obj) &&
-            !rb_gc_impl_garbage_object_p(objspace, obj)) {
-        return obj;
-    }
-
-    if (rb_funcall(object_id, rb_intern(">="), 1, ULL2NUM(objspace->next_object_id))) {
-        rb_raise(rb_eRangeError, "%+"PRIsVALUE" is not id value", rb_funcall(object_id, rb_intern("to_s"), 1, INT2FIX(10)));
-    }
-    else {
-        rb_raise(rb_eRangeError, "%+"PRIsVALUE" is recycled object", rb_funcall(object_id, rb_intern("to_s"), 1, INT2FIX(10)));
-    }
-}
-
-VALUE
-rb_gc_impl_object_id(void *objspace_ptr, VALUE obj)
-{
-    VALUE id;
-    rb_objspace_t *objspace = objspace_ptr;
-
-    unsigned int lev = rb_gc_vm_lock();
-    if (FL_TEST(obj, FL_SEEN_OBJ_ID)) {
-        st_data_t val;
-        if (st_lookup(objspace->obj_to_id_tbl, (st_data_t)obj, &val)) {
-            id = (VALUE)val;
-        }
-        else {
-            rb_bug("rb_gc_impl_object_id: FL_SEEN_OBJ_ID flag set but not found in table");
-        }
-    }
-    else {
-        GC_ASSERT(!st_lookup(objspace->obj_to_id_tbl, (st_data_t)obj, NULL));
-
-        id = ULL2NUM(objspace->next_object_id);
-        objspace->next_object_id += OBJ_ID_INCREMENT;
-
-        st_insert(objspace->obj_to_id_tbl, (st_data_t)obj, (st_data_t)id);
-        st_insert(objspace->id_to_obj_tbl, (st_data_t)id, (st_data_t)obj);
-        FL_SET(obj, FL_SEEN_OBJ_ID);
-    }
-    rb_gc_vm_unlock(lev);
-
-    return id;
-}
-
-static void free_stack_chunks(mark_stack_t *);
-static void mark_stack_free_cache(mark_stack_t *);
-static void heap_page_free(rb_objspace_t *objspace, struct heap_page *page);
-
-static inline void
-heap_page_add_freeobj(rb_objspace_t *objspace, struct heap_page *page, VALUE obj)
-{
-    asan_unpoison_object(obj, false);
-
-    asan_unlock_freelist(page);
-
-    struct free_slot *slot = (struct free_slot *)obj;
-    slot->flags = 0;
-    slot->next = page->freelist;
-    page->freelist = slot;
-    asan_lock_freelist(page);
-
-    RVALUE_AGE_RESET(obj);
-
-    if (RGENGC_CHECK_MODE &&
-        /* obj should belong to page */
-        !(page->start <= (uintptr_t)obj &&
-          (uintptr_t)obj   <  ((uintptr_t)page->start + (page->total_slots * page->slot_size)) &&
-          obj % BASE_SLOT_SIZE == 0)) {
-        rb_bug("heap_page_add_freeobj: %p is not rvalue.", (void *)obj);
-    }
-
-    asan_poison_object(obj);
-    gc_report(3, objspace, "heap_page_add_freeobj: add %p to freelist\n", (void *)obj);
-}
-
-static void
-heap_allocatable_slots_expand(rb_objspace_t *objspace,
-        rb_heap_t *heap, size_t free_slots, size_t total_slots)
-{
-    double goal_ratio = gc_params.heap_free_slots_goal_ratio;
-    size_t target_total_slots;
-
-    if (goal_ratio == 0.0) {
-        target_total_slots = (size_t)(total_slots * gc_params.growth_factor);
-    }
-    else if (total_slots == 0) {
-        target_total_slots = minimum_slots_for_heap(objspace, heap);
-    }
-    else {
-        /* Find `f' where free_slots = f * total_slots * goal_ratio
-         * => f = (total_slots - free_slots) / ((1 - goal_ratio) * total_slots)
-         */
-        double f = (double)(total_slots - free_slots) / ((1 - goal_ratio) * total_slots);
-
-        if (f > gc_params.growth_factor) f = gc_params.growth_factor;
-        if (f < 1.0) f = 1.1;
-
-        target_total_slots = (size_t)(f * total_slots);
-
-        if (0) {
-            fprintf(stderr,
-                    "free_slots(%8"PRIuSIZE")/total_slots(%8"PRIuSIZE")=%1.2f,"
-                    " G(%1.2f), f(%1.2f),"
-                    " total_slots(%8"PRIuSIZE") => target_total_slots(%8"PRIuSIZE")\n",
-                    free_slots, total_slots, free_slots/(double)total_slots,
-                    goal_ratio, f, total_slots, target_total_slots);
-        }
-    }
-
-    if (gc_params.growth_max_slots > 0) {
-        size_t max_total_slots = (size_t)(total_slots + gc_params.growth_max_slots);
-        if (target_total_slots > max_total_slots) target_total_slots = max_total_slots;
-    }
-
-    size_t extend_slot_count = target_total_slots - total_slots;
-    /* Extend by at least 1 page. */
-    if (extend_slot_count == 0) extend_slot_count = 1;
-
-    objspace->heap_pages.allocatable_slots += extend_slot_count;
-}
-
-static inline void
-heap_add_freepage(rb_heap_t *heap, struct heap_page *page)
-{
-    asan_unlock_freelist(page);
-    GC_ASSERT(page->free_slots != 0);
-    GC_ASSERT(page->freelist != NULL);
-
-    page->free_next = heap->free_pages;
-    heap->free_pages = page;
-
-    RUBY_DEBUG_LOG("page:%p freelist:%p", (void *)page, (void *)page->freelist);
-
-    asan_lock_freelist(page);
-}
-
-static inline void
-heap_add_poolpage(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
-{
-    asan_unlock_freelist(page);
-    GC_ASSERT(page->free_slots != 0);
-    GC_ASSERT(page->freelist != NULL);
-
-    page->free_next = heap->pooled_pages;
-    heap->pooled_pages = page;
-    objspace->rincgc.pooled_slots += page->free_slots;
-
-    asan_lock_freelist(page);
-}
-
-static void
-heap_unlink_page(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
-{
-    ccan_list_del(&page->page_node);
-    heap->total_pages--;
-    heap->total_slots -= page->total_slots;
-}
-
-static void
-gc_aligned_free(void *ptr, size_t size)
-{
-#if defined __MINGW32__
-    __mingw_aligned_free(ptr);
-#elif defined _WIN32
-    _aligned_free(ptr);
-#elif defined(HAVE_POSIX_MEMALIGN) || defined(HAVE_MEMALIGN)
-    free(ptr);
-#else
-    free(((void**)ptr)[-1]);
-#endif
-}
-
-static void
-heap_page_body_free(struct heap_page_body *page_body)
-{
-    GC_ASSERT((uintptr_t)page_body % HEAP_PAGE_ALIGN == 0);
-
-    if (HEAP_PAGE_ALLOC_USE_MMAP) {
-#ifdef HAVE_MMAP
-        GC_ASSERT(HEAP_PAGE_SIZE % sysconf(_SC_PAGE_SIZE) == 0);
-        if (munmap(page_body, HEAP_PAGE_SIZE)) {
-            rb_bug("heap_page_body_free: munmap failed");
-        }
-#endif
-    }
-    else {
-        gc_aligned_free(page_body, HEAP_PAGE_SIZE);
-    }
-}
-
-static void
-heap_page_free(rb_objspace_t *objspace, struct heap_page *page)
-{
-    objspace->heap_pages.freed_pages++;
-    heap_page_body_free(page->body);
-    free(page);
-}
-
-static void
-heap_pages_free_unused_pages(rb_objspace_t *objspace)
-{
-    size_t pages_to_keep_count =
-        // Get number of pages estimated for the smallest size pool
-        CEILDIV(objspace->heap_pages.allocatable_slots, HEAP_PAGE_OBJ_LIMIT) *
-            // Estimate the average slot size multiple
-            (1 << (HEAP_COUNT / 2));
-
-    if (objspace->empty_pages != NULL && objspace->empty_pages_count > pages_to_keep_count) {
-        GC_ASSERT(objspace->empty_pages_count > 0);
-        objspace->empty_pages = NULL;
-        objspace->empty_pages_count = 0;
-
-        size_t i, j;
-        for (i = j = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-            struct heap_page *page = rb_darray_get(objspace->heap_pages.sorted, i);
-
-            if (heap_page_in_global_empty_pages_pool(objspace, page) && pages_to_keep_count == 0) {
-                heap_page_free(objspace, page);
-            }
-            else {
-                if (heap_page_in_global_empty_pages_pool(objspace, page) && pages_to_keep_count > 0) {
-                    page->free_next = objspace->empty_pages;
-                    objspace->empty_pages = page;
-                    objspace->empty_pages_count++;
-                    pages_to_keep_count--;
-                }
-
-                if (i != j) {
-                    rb_darray_set(objspace->heap_pages.sorted, j, page);
-                }
-                j++;
-            }
-        }
-
-        rb_darray_pop(objspace->heap_pages.sorted, i - j);
-        GC_ASSERT(rb_darray_size(objspace->heap_pages.sorted) == j);
-
-        struct heap_page *hipage = rb_darray_get(objspace->heap_pages.sorted, rb_darray_size(objspace->heap_pages.sorted) - 1);
-        uintptr_t himem = (uintptr_t)hipage->body + HEAP_PAGE_SIZE;
-        GC_ASSERT(himem <= heap_pages_himem);
-        heap_pages_himem = himem;
-
-        struct heap_page *lopage = rb_darray_get(objspace->heap_pages.sorted, 0);
-        uintptr_t lomem = (uintptr_t)lopage->body + sizeof(struct heap_page_header);
-        GC_ASSERT(lomem >= heap_pages_lomem);
-        heap_pages_lomem = lomem;
-    }
-}
-
-static void *
-gc_aligned_malloc(size_t alignment, size_t size)
-{
-    /* alignment must be a power of 2 */
-    GC_ASSERT(((alignment - 1) & alignment) == 0);
-    GC_ASSERT(alignment % sizeof(void*) == 0);
-
-    void *res;
-
-#if defined __MINGW32__
-    res = __mingw_aligned_malloc(size, alignment);
-#elif defined _WIN32
-    void *_aligned_malloc(size_t, size_t);
-    res = _aligned_malloc(size, alignment);
-#elif defined(HAVE_POSIX_MEMALIGN)
-    if (posix_memalign(&res, alignment, size) != 0) {
-        return NULL;
-    }
-#elif defined(HAVE_MEMALIGN)
-    res = memalign(alignment, size);
-#else
-    char* aligned;
-    res = malloc(alignment + size + sizeof(void*));
-    aligned = (char*)res + alignment + sizeof(void*);
-    aligned -= ((VALUE)aligned & (alignment - 1));
-    ((void**)aligned)[-1] = res;
-    res = (void*)aligned;
-#endif
-
-    GC_ASSERT((uintptr_t)res % alignment == 0);
-
-    return res;
-}
-
-static struct heap_page_body *
-heap_page_body_allocate(void)
-{
-    struct heap_page_body *page_body;
-
-    if (HEAP_PAGE_ALLOC_USE_MMAP) {
-#ifdef HAVE_MMAP
-        GC_ASSERT(HEAP_PAGE_ALIGN % sysconf(_SC_PAGE_SIZE) == 0);
-
-        size_t mmap_size = HEAP_PAGE_ALIGN + HEAP_PAGE_SIZE;
-        char *ptr = mmap(NULL, mmap_size,
-                         PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-        if (ptr == MAP_FAILED) {
-            return NULL;
-        }
-
-        // If we are building `default.c` as part of the ruby executable, we
-        // may just call `ruby_annotate_mmap`.  But if we are building
-        // `default.c` as a shared library, we will not have access to private
-        // symbols, and we have to either call prctl directly or make our own
-        // wrapper.
-#if defined(HAVE_SYS_PRCTL_H) && defined(PR_SET_VMA) && defined(PR_SET_VMA_ANON_NAME)
-        prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, mmap_size, "Ruby:GC:default:heap_page_body_allocate");
-        errno = 0;
-#endif
-
-        char *aligned = ptr + HEAP_PAGE_ALIGN;
-        aligned -= ((VALUE)aligned & (HEAP_PAGE_ALIGN - 1));
-        GC_ASSERT(aligned > ptr);
-        GC_ASSERT(aligned <= ptr + HEAP_PAGE_ALIGN);
-
-        size_t start_out_of_range_size = aligned - ptr;
-        GC_ASSERT(start_out_of_range_size % sysconf(_SC_PAGE_SIZE) == 0);
-        if (start_out_of_range_size > 0) {
-            if (munmap(ptr, start_out_of_range_size)) {
-                rb_bug("heap_page_body_allocate: munmap failed for start");
-            }
-        }
-
-        size_t end_out_of_range_size = HEAP_PAGE_ALIGN - start_out_of_range_size;
-        GC_ASSERT(end_out_of_range_size % sysconf(_SC_PAGE_SIZE) == 0);
-        if (end_out_of_range_size > 0) {
-            if (munmap(aligned + HEAP_PAGE_SIZE, end_out_of_range_size)) {
-                rb_bug("heap_page_body_allocate: munmap failed for end");
-            }
-        }
-
-        page_body = (struct heap_page_body *)aligned;
-#endif
-    }
-    else {
-        page_body = gc_aligned_malloc(HEAP_PAGE_ALIGN, HEAP_PAGE_SIZE);
-    }
-
-    GC_ASSERT((uintptr_t)page_body % HEAP_PAGE_ALIGN == 0);
-
-    return page_body;
-}
-
-static struct heap_page *
-heap_page_resurrect(rb_objspace_t *objspace)
-{
-    struct heap_page *page = NULL;
-    if (objspace->empty_pages != NULL) {
-        GC_ASSERT(objspace->empty_pages_count > 0);
-        objspace->empty_pages_count--;
-        page = objspace->empty_pages;
-        objspace->empty_pages = page->free_next;
-    }
-
-    return page;
-}
-
-static struct heap_page *
-heap_page_allocate(rb_objspace_t *objspace)
-{
-    struct heap_page_body *page_body = heap_page_body_allocate();
-    if (page_body == 0) {
-        rb_memerror();
-    }
-
-    struct heap_page *page = calloc1(sizeof(struct heap_page));
-    if (page == 0) {
-        heap_page_body_free(page_body);
-        rb_memerror();
-    }
-
-    uintptr_t start = (uintptr_t)page_body + sizeof(struct heap_page_header);
-    uintptr_t end = (uintptr_t)page_body + HEAP_PAGE_SIZE;
-
-    size_t lo = 0;
-    size_t hi = rb_darray_size(objspace->heap_pages.sorted);
-    while (lo < hi) {
-        struct heap_page *mid_page;
-
-        size_t mid = (lo + hi) / 2;
-        mid_page = rb_darray_get(objspace->heap_pages.sorted, mid);
-        if ((uintptr_t)mid_page->start < start) {
-            lo = mid + 1;
-        }
-        else if ((uintptr_t)mid_page->start > start) {
-            hi = mid;
-        }
-        else {
-            rb_bug("same heap page is allocated: %p at %"PRIuVALUE, (void *)page_body, (VALUE)mid);
-        }
-    }
-
-    rb_darray_insert(&objspace->heap_pages.sorted, hi, page);
-
-    if (heap_pages_lomem == 0 || heap_pages_lomem > start) heap_pages_lomem = start;
-    if (heap_pages_himem < end) heap_pages_himem = end;
-
-    page->body = page_body;
-    page_body->header.page = page;
-
-    objspace->heap_pages.allocated_pages++;
-
-    return page;
-}
-
-static void
-heap_add_page(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
-{
-    /* Adding to eden heap during incremental sweeping is forbidden */
-    GC_ASSERT(!heap->sweeping_page);
-    GC_ASSERT(heap_page_in_global_empty_pages_pool(objspace, page));
-
-    /* adjust obj_limit (object number available in this page) */
-    uintptr_t start = (uintptr_t)page->body + sizeof(struct heap_page_header);
-    if (start % BASE_SLOT_SIZE != 0) {
-        int delta = BASE_SLOT_SIZE - (start % BASE_SLOT_SIZE);
-        start = start + delta;
-        GC_ASSERT(NUM_IN_PAGE(start) == 0 || NUM_IN_PAGE(start) == 1);
-
-        /* Find a num in page that is evenly divisible by `stride`.
-         * This is to ensure that objects are aligned with bit planes.
-         * In other words, ensure there are an even number of objects
-         * per bit plane. */
-        if (NUM_IN_PAGE(start) == 1) {
-            start += heap->slot_size - BASE_SLOT_SIZE;
-        }
-
-        GC_ASSERT(NUM_IN_PAGE(start) * BASE_SLOT_SIZE % heap->slot_size == 0);
-    }
-
-    int slot_count = (int)((HEAP_PAGE_SIZE - (start - (uintptr_t)page->body))/heap->slot_size);
-
-    page->start = start;
-    page->total_slots = slot_count;
-    page->slot_size = heap->slot_size;
-    page->heap = heap;
-
-    asan_unlock_freelist(page);
-    page->freelist = NULL;
-    asan_unpoison_memory_region(page->body, HEAP_PAGE_SIZE, false);
-    for (VALUE p = (VALUE)start; p < start + (slot_count * heap->slot_size); p += heap->slot_size) {
-        heap_page_add_freeobj(objspace, page, p);
-    }
-    asan_lock_freelist(page);
-
-    page->free_slots = slot_count;
-
-    heap->total_allocated_pages++;
-
-    ccan_list_add_tail(&heap->pages, &page->page_node);
-    heap->total_pages++;
-    heap->total_slots += page->total_slots;
-}
-
-static int
-heap_page_allocate_and_initialize(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    if (objspace->heap_pages.allocatable_slots > 0) {
-        gc_report(1, objspace, "heap_page_allocate_and_initialize: rb_darray_size(objspace->heap_pages.sorted): %"PRIdSIZE", "
-                  "allocatable_slots: %"PRIdSIZE", heap->total_pages: %"PRIdSIZE"\n",
-                  rb_darray_size(objspace->heap_pages.sorted), objspace->heap_pages.allocatable_slots, heap->total_pages);
-
-        struct heap_page *page = heap_page_resurrect(objspace);
-        if (page == NULL) {
-            page = heap_page_allocate(objspace);
-        }
-        heap_add_page(objspace, heap, page);
-        heap_add_freepage(heap, page);
-
-        if (objspace->heap_pages.allocatable_slots > (size_t)page->total_slots) {
-            objspace->heap_pages.allocatable_slots -= page->total_slots;
-        }
-        else {
-            objspace->heap_pages.allocatable_slots = 0;
-        }
-
-        return true;
-    }
-
-    return false;
-}
-
-static void
-heap_page_allocate_and_initialize_force(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    size_t prev_allocatable_slots = objspace->heap_pages.allocatable_slots;
-    // Set allocatable slots to 1 to force a page to be created.
-    objspace->heap_pages.allocatable_slots = 1;
-    heap_page_allocate_and_initialize(objspace, heap);
-    GC_ASSERT(heap->free_pages != NULL);
-    objspace->heap_pages.allocatable_slots = prev_allocatable_slots;
-}
-
-static void
-gc_continue(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    unsigned int lock_lev;
-    gc_enter(objspace, gc_enter_event_continue, &lock_lev);
-
-    /* Continue marking if in incremental marking. */
-    if (is_incremental_marking(objspace)) {
-        if (gc_marks_continue(objspace, heap)) {
-            gc_sweep(objspace);
-        }
-    }
-
-    /* Continue sweeping if in lazy sweeping or the previous incremental
-     * marking finished and did not yield a free page. */
-    if (heap->free_pages == NULL && is_lazy_sweeping(objspace)) {
-        gc_sweep_continue(objspace, heap);
-    }
-
-    gc_exit(objspace, gc_enter_event_continue, &lock_lev);
-}
-
-static void
-heap_prepare(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    GC_ASSERT(heap->free_pages == NULL);
-
-    if (heap->total_slots < gc_params.heap_init_slots[heap - heaps] &&
-            heap->sweeping_page == NULL) {
-        heap_page_allocate_and_initialize_force(objspace, heap);
-        GC_ASSERT(heap->free_pages != NULL);
-        return;
-    }
-
-    /* Continue incremental marking or lazy sweeping, if in any of those steps. */
-    gc_continue(objspace, heap);
-
-    if (heap->free_pages == NULL) {
-        heap_page_allocate_and_initialize(objspace, heap);
-    }
-
-    /* If we still don't have a free page and not allowed to create a new page,
-     * we should start a new GC cycle. */
-    if (heap->free_pages == NULL) {
-        if (gc_start(objspace, GPR_FLAG_NEWOBJ) == FALSE) {
-            rb_memerror();
-        }
-        else {
-            if (objspace->heap_pages.allocatable_slots == 0 && !gc_config_full_mark_val) {
-                heap_allocatable_slots_expand(objspace, heap,
-                        heap->freed_slots + heap->empty_slots,
-                        heap->total_slots);
-                GC_ASSERT(objspace->heap_pages.allocatable_slots > 0);
-            }
-            /* Do steps of incremental marking or lazy sweeping if the GC run permits. */
-            gc_continue(objspace, heap);
-
-            /* If we're not incremental marking (e.g. a minor GC) or finished
-             * sweeping and still don't have a free page, then
-             * gc_sweep_finish_heap should allow us to create a new page. */
-            if (heap->free_pages == NULL && !heap_page_allocate_and_initialize(objspace, heap)) {
-                if (gc_needs_major_flags == GPR_FLAG_NONE) {
-                    rb_bug("cannot create a new page after GC");
-                }
-                else { // Major GC is required, which will allow us to create new page
-                    if (gc_start(objspace, GPR_FLAG_NEWOBJ) == FALSE) {
-                        rb_memerror();
-                    }
-                    else {
-                        /* Do steps of incremental marking or lazy sweeping. */
-                        gc_continue(objspace, heap);
-
-                        if (heap->free_pages == NULL &&
-                                !heap_page_allocate_and_initialize(objspace, heap)) {
-                            rb_bug("cannot create a new page after major GC");
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    GC_ASSERT(heap->free_pages != NULL);
-}
-
-static inline VALUE
-newobj_fill(VALUE obj, VALUE v1, VALUE v2, VALUE v3)
-{
-    VALUE *p = (VALUE *)obj;
-    p[2] = v1;
-    p[3] = v2;
-    p[4] = v3;
-    return obj;
-}
-
-#if GC_DEBUG
-static inline const char*
-rb_gc_impl_source_location_cstr(int *ptr)
-{
-    /* We could directly refer `rb_source_location_cstr()` before, but not any
-     * longer.  We have to heavy lift using our debugging API. */
-    if (! ptr) {
-        return NULL;
-    }
-    else if (! (*ptr = rb_sourceline())) {
-        return NULL;
-    }
-    else {
-        return rb_sourcefile();
-    }
-}
-#endif
-
-static inline VALUE
-newobj_init(VALUE klass, VALUE flags, int wb_protected, rb_objspace_t *objspace, VALUE obj)
-{
-#if !__has_feature(memory_sanitizer)
-    GC_ASSERT(BUILTIN_TYPE(obj) == T_NONE);
-    GC_ASSERT((flags & FL_WB_PROTECTED) == 0);
-#endif
-    RBASIC(obj)->flags = flags;
-    *((VALUE *)&RBASIC(obj)->klass) = klass;
-
-    int t = flags & RUBY_T_MASK;
-    if (t == T_CLASS || t == T_MODULE || t == T_ICLASS) {
-        RVALUE_AGE_SET_CANDIDATE(objspace, obj);
-    }
-
-#if RACTOR_CHECK_MODE
-    void rb_ractor_setup_belonging(VALUE obj);
-    rb_ractor_setup_belonging(obj);
-#endif
-
-#if RGENGC_CHECK_MODE
-    newobj_fill(obj, 0, 0, 0);
-
-    int lev = rb_gc_vm_lock_no_barrier();
-    {
-        check_rvalue_consistency(objspace, obj);
-
-        GC_ASSERT(RVALUE_MARKED(objspace, obj) == FALSE);
-        GC_ASSERT(RVALUE_MARKING(objspace, obj) == FALSE);
-        GC_ASSERT(RVALUE_OLD_P(objspace, obj) == FALSE);
-        GC_ASSERT(RVALUE_WB_UNPROTECTED(objspace, obj) == FALSE);
-
-        if (RVALUE_REMEMBERED(objspace, obj)) rb_bug("newobj: %s is remembered.", rb_obj_info(obj));
-    }
-    rb_gc_vm_unlock_no_barrier(lev);
-#endif
-
-    if (RB_UNLIKELY(wb_protected == FALSE)) {
-        MARK_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(obj), obj);
-    }
-
-#if RGENGC_PROFILE
-    if (wb_protected) {
-        objspace->profile.total_generated_normal_object_count++;
-#if RGENGC_PROFILE >= 2
-        objspace->profile.generated_normal_object_count_types[BUILTIN_TYPE(obj)]++;
-#endif
-    }
-    else {
-        objspace->profile.total_generated_shady_object_count++;
-#if RGENGC_PROFILE >= 2
-        objspace->profile.generated_shady_object_count_types[BUILTIN_TYPE(obj)]++;
-#endif
-    }
-#endif
-
-#if GC_DEBUG
-    GET_RVALUE_OVERHEAD(obj)->file = rb_gc_impl_source_location_cstr(&GET_RVALUE_OVERHEAD(obj)->line);
-    GC_ASSERT(!SPECIAL_CONST_P(obj)); /* check alignment */
-#endif
-
-    gc_report(5, objspace, "newobj: %s\n", rb_obj_info(obj));
-
-    RUBY_DEBUG_LOG("obj:%p (%s)", (void *)obj, rb_obj_info(obj));
-    return obj;
-}
-
-size_t
-rb_gc_impl_obj_slot_size(VALUE obj)
-{
-    return GET_HEAP_PAGE(obj)->slot_size - RVALUE_OVERHEAD;
-}
-
-static inline size_t
-heap_slot_size(unsigned char pool_id)
-{
-    GC_ASSERT(pool_id < HEAP_COUNT);
-
-    size_t slot_size = (1 << pool_id) * BASE_SLOT_SIZE;
-
-#if RGENGC_CHECK_MODE
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    GC_ASSERT(heaps[pool_id].slot_size == (short)slot_size);
-#endif
-
-    slot_size -= RVALUE_OVERHEAD;
-
-    return slot_size;
-}
-
-bool
-rb_gc_impl_size_allocatable_p(size_t size)
-{
-    return size <= heap_slot_size(HEAP_COUNT - 1);
-}
-
-static inline VALUE
-ractor_cache_allocate_slot(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache,
-                           size_t heap_idx)
-{
-    rb_ractor_newobj_heap_cache_t *heap_cache = &cache->heap_caches[heap_idx];
-    struct free_slot *p = heap_cache->freelist;
-
-    if (RB_UNLIKELY(is_incremental_marking(objspace))) {
-        // Not allowed to allocate without running an incremental marking step
-        if (cache->incremental_mark_step_allocated_slots >= INCREMENTAL_MARK_STEP_ALLOCATIONS) {
-            return Qfalse;
-        }
-
-        if (p) {
-            cache->incremental_mark_step_allocated_slots++;
-        }
-    }
-
-    if (RB_LIKELY(p)) {
-        VALUE obj = (VALUE)p;
-        MAYBE_UNUSED(const size_t) stride = heap_slot_size(heap_idx);
-        heap_cache->freelist = p->next;
-        asan_unpoison_memory_region(p, stride, true);
-#if RGENGC_CHECK_MODE
-        GC_ASSERT(rb_gc_impl_obj_slot_size(obj) == stride);
-        // zero clear
-        MEMZERO((char *)obj, char, stride);
-#endif
-        return obj;
-    }
-    else {
-        return Qfalse;
-    }
-}
-
-static struct heap_page *
-heap_next_free_page(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    struct heap_page *page;
-
-    if (heap->free_pages == NULL) {
-        heap_prepare(objspace, heap);
-    }
-
-    page = heap->free_pages;
-    heap->free_pages = page->free_next;
-
-    GC_ASSERT(page->free_slots != 0);
-
-    asan_unlock_freelist(page);
-
-    return page;
-}
-
-static inline void
-ractor_cache_set_page(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx,
-                      struct heap_page *page)
-{
-    gc_report(3, objspace, "ractor_set_cache: Using page %p\n", (void *)page->body);
-
-    rb_ractor_newobj_heap_cache_t *heap_cache = &cache->heap_caches[heap_idx];
-
-    GC_ASSERT(heap_cache->freelist == NULL);
-    GC_ASSERT(page->free_slots != 0);
-    GC_ASSERT(page->freelist != NULL);
-
-    heap_cache->using_page = page;
-    heap_cache->freelist = page->freelist;
-    page->free_slots = 0;
-    page->freelist = NULL;
-
-    asan_unpoison_object((VALUE)heap_cache->freelist, false);
-    GC_ASSERT(RB_TYPE_P((VALUE)heap_cache->freelist, T_NONE));
-    asan_poison_object((VALUE)heap_cache->freelist);
-}
-
-static inline size_t
-heap_idx_for_size(size_t size)
-{
-    size += RVALUE_OVERHEAD;
-
-    size_t slot_count = CEILDIV(size, BASE_SLOT_SIZE);
-
-    /* heap_idx is ceil(log2(slot_count)) */
-    size_t heap_idx = 64 - nlz_int64(slot_count - 1);
-
-    if (heap_idx >= HEAP_COUNT) {
-        rb_bug("heap_idx_for_size: allocation size too large "
-               "(size=%"PRIuSIZE"u, heap_idx=%"PRIuSIZE"u)", size, heap_idx);
-    }
-
-#if RGENGC_CHECK_MODE
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    GC_ASSERT(size <= (size_t)heaps[heap_idx].slot_size);
-    if (heap_idx > 0) GC_ASSERT(size > (size_t)heaps[heap_idx - 1].slot_size);
-#endif
-
-    return heap_idx;
-}
-
-size_t
-rb_gc_impl_heap_id_for_size(void *objspace_ptr, size_t size)
-{
-    return heap_idx_for_size(size);
-}
-
-
-static size_t heap_sizes[HEAP_COUNT + 1] = { 0 };
-
-size_t *
-rb_gc_impl_heap_sizes(void *objspace_ptr)
-{
-    if (heap_sizes[0] == 0) {
-        for (unsigned char i = 0; i < HEAP_COUNT; i++) {
-            heap_sizes[i] = heap_slot_size(i);
-        }
-    }
-
-    return heap_sizes;
-}
-
-NOINLINE(static VALUE newobj_cache_miss(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx, bool vm_locked));
-
-static VALUE
-newobj_cache_miss(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx, bool vm_locked)
-{
-    rb_heap_t *heap = &heaps[heap_idx];
-    VALUE obj = Qfalse;
-
-    unsigned int lev = 0;
-    bool unlock_vm = false;
-
-    if (!vm_locked) {
-        lev = rb_gc_cr_lock();
-        vm_locked = true;
-        unlock_vm = true;
-    }
-
-    {
-        if (is_incremental_marking(objspace)) {
-            gc_continue(objspace, heap);
-            cache->incremental_mark_step_allocated_slots = 0;
-
-            // Retry allocation after resetting incremental_mark_step_allocated_slots
-            obj = ractor_cache_allocate_slot(objspace, cache, heap_idx);
-        }
-
-        if (obj == Qfalse) {
-            // Get next free page (possibly running GC)
-            struct heap_page *page = heap_next_free_page(objspace, heap);
-            ractor_cache_set_page(objspace, cache, heap_idx, page);
-
-            // Retry allocation after moving to new page
-            obj = ractor_cache_allocate_slot(objspace, cache, heap_idx);
-        }
-    }
-
-    if (unlock_vm) {
-        rb_gc_cr_unlock(lev);
-    }
-
-    if (RB_UNLIKELY(obj == Qfalse)) {
-        rb_memerror();
-    }
-    return obj;
-}
-
-static VALUE
-newobj_alloc(rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx, bool vm_locked)
-{
-    VALUE obj = ractor_cache_allocate_slot(objspace, cache, heap_idx);
-
-    if (RB_UNLIKELY(obj == Qfalse)) {
-        obj = newobj_cache_miss(objspace, cache, heap_idx, vm_locked);
-    }
-
-    rb_heap_t *heap = &heaps[heap_idx];
-    heap->total_allocated_objects++;
-    GC_ASSERT(rb_gc_multi_ractor_p() ||
-        heap->total_slots >=
-            (heap->total_allocated_objects - heap->total_freed_objects - heap->final_slots_count));
-
-    return obj;
-}
-
-ALWAYS_INLINE(static VALUE newobj_slowpath(VALUE klass, VALUE flags, rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, int wb_protected, size_t heap_idx));
-
-static inline VALUE
-newobj_slowpath(VALUE klass, VALUE flags, rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, int wb_protected, size_t heap_idx)
-{
-    VALUE obj;
-    unsigned int lev;
-
-    lev = rb_gc_cr_lock();
-    {
-        if (RB_UNLIKELY(during_gc || ruby_gc_stressful)) {
-            if (during_gc) {
-                dont_gc_on();
-                during_gc = 0;
-                rb_bug("object allocation during garbage collection phase");
-            }
-
-            if (ruby_gc_stressful) {
-                if (!garbage_collect(objspace, GPR_FLAG_NEWOBJ)) {
-                    rb_memerror();
-                }
-            }
-        }
-
-        obj = newobj_alloc(objspace, cache, heap_idx, true);
-        newobj_init(klass, flags, wb_protected, objspace, obj);
-    }
-    rb_gc_cr_unlock(lev);
-
-    return obj;
-}
-
-NOINLINE(static VALUE newobj_slowpath_wb_protected(VALUE klass, VALUE flags,
-                                                   rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx));
-NOINLINE(static VALUE newobj_slowpath_wb_unprotected(VALUE klass, VALUE flags,
-                                                     rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx));
-
-static VALUE
-newobj_slowpath_wb_protected(VALUE klass, VALUE flags, rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx)
-{
-    return newobj_slowpath(klass, flags, objspace, cache, TRUE, heap_idx);
-}
-
-static VALUE
-newobj_slowpath_wb_unprotected(VALUE klass, VALUE flags, rb_objspace_t *objspace, rb_ractor_newobj_cache_t *cache, size_t heap_idx)
-{
-    return newobj_slowpath(klass, flags, objspace, cache, FALSE, heap_idx);
-}
-
-VALUE
-rb_gc_impl_new_obj(void *objspace_ptr, void *cache_ptr, VALUE klass, VALUE flags, VALUE v1, VALUE v2, VALUE v3, bool wb_protected, size_t alloc_size)
-{
-    VALUE obj;
-    rb_objspace_t *objspace = objspace_ptr;
-
-    RB_DEBUG_COUNTER_INC(obj_newobj);
-    (void)RB_DEBUG_COUNTER_INC_IF(obj_newobj_wb_unprotected, !wb_protected);
-
-    if (RB_UNLIKELY(stress_to_class)) {
-        long cnt = RARRAY_LEN(stress_to_class);
-        for (long i = 0; i < cnt; i++) {
-            if (klass == RARRAY_AREF(stress_to_class, i)) rb_memerror();
-        }
-    }
-
-    size_t heap_idx = heap_idx_for_size(alloc_size);
-
-    rb_ractor_newobj_cache_t *cache = (rb_ractor_newobj_cache_t *)cache_ptr;
-
-    if (!RB_UNLIKELY(during_gc || ruby_gc_stressful) &&
-            wb_protected) {
-        obj = newobj_alloc(objspace, cache, heap_idx, false);
-        newobj_init(klass, flags, wb_protected, objspace, obj);
-    }
-    else {
-        RB_DEBUG_COUNTER_INC(obj_newobj_slowpath);
-
-        obj = wb_protected ?
-          newobj_slowpath_wb_protected(klass, flags, objspace, cache, heap_idx) :
-          newobj_slowpath_wb_unprotected(klass, flags, objspace, cache, heap_idx);
-    }
-
-    return newobj_fill(obj, v1, v2, v3);
-}
-
-static int
-ptr_in_page_body_p(const void *ptr, const void *memb)
-{
-    struct heap_page *page = *(struct heap_page **)memb;
-    uintptr_t p_body = (uintptr_t)page->body;
-
-    if ((uintptr_t)ptr >= p_body) {
-        return (uintptr_t)ptr < (p_body + HEAP_PAGE_SIZE) ? 0 : 1;
-    }
-    else {
-        return -1;
-    }
-}
-
-PUREFUNC(static inline struct heap_page *heap_page_for_ptr(rb_objspace_t *objspace, uintptr_t ptr);)
-static inline struct heap_page *
-heap_page_for_ptr(rb_objspace_t *objspace, uintptr_t ptr)
-{
-    struct heap_page **res;
-
-    if (ptr < (uintptr_t)heap_pages_lomem ||
-            ptr > (uintptr_t)heap_pages_himem) {
-        return NULL;
-    }
-
-    res = bsearch((void *)ptr, rb_darray_ref(objspace->heap_pages.sorted, 0),
-                  rb_darray_size(objspace->heap_pages.sorted), sizeof(struct heap_page *),
-                  ptr_in_page_body_p);
-
-    if (res) {
-        return *res;
-    }
-    else {
-        return NULL;
-    }
-}
-
-PUREFUNC(static inline bool is_pointer_to_heap(rb_objspace_t *objspace, const void *ptr);)
-static inline bool
-is_pointer_to_heap(rb_objspace_t *objspace, const void *ptr)
-{
-    register uintptr_t p = (uintptr_t)ptr;
-    register struct heap_page *page;
-
-    RB_DEBUG_COUNTER_INC(gc_isptr_trial);
-
-    if (p < heap_pages_lomem || p > heap_pages_himem) return FALSE;
-    RB_DEBUG_COUNTER_INC(gc_isptr_range);
-
-    if (p % BASE_SLOT_SIZE != 0) return FALSE;
-    RB_DEBUG_COUNTER_INC(gc_isptr_align);
-
-    page = heap_page_for_ptr(objspace, (uintptr_t)ptr);
-    if (page) {
-        RB_DEBUG_COUNTER_INC(gc_isptr_maybe);
-        if (heap_page_in_global_empty_pages_pool(objspace, page)) {
-            return FALSE;
-        }
-        else {
-            if (p < page->start) return FALSE;
-            if (p >= page->start + (page->total_slots * page->slot_size)) return FALSE;
-            if ((NUM_IN_PAGE(p) * BASE_SLOT_SIZE) % page->slot_size != 0) return FALSE;
-
-            return TRUE;
-        }
-    }
-    return FALSE;
-}
-
-bool
-rb_gc_impl_pointer_to_heap_p(void *objspace_ptr, const void *ptr)
-{
-    return is_pointer_to_heap(objspace_ptr, ptr);
-}
-
-#define ZOMBIE_OBJ_KEPT_FLAGS (FL_SEEN_OBJ_ID | FL_FINALIZE)
-
-void
-rb_gc_impl_make_zombie(void *objspace_ptr, VALUE obj, void (*dfree)(void *), void *data)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    struct RZombie *zombie = RZOMBIE(obj);
-    zombie->basic.flags = T_ZOMBIE | (zombie->basic.flags & ZOMBIE_OBJ_KEPT_FLAGS);
-    zombie->dfree = dfree;
-    zombie->data = data;
-    VALUE prev, next = heap_pages_deferred_final;
-    do {
-        zombie->next = prev = next;
-        next = RUBY_ATOMIC_VALUE_CAS(heap_pages_deferred_final, prev, obj);
-    } while (next != prev);
-
-    struct heap_page *page = GET_HEAP_PAGE(obj);
-    page->final_slots++;
-    page->heap->final_slots_count++;
-}
-
-static void
-obj_free_object_id(rb_objspace_t *objspace, VALUE obj)
-{
-    st_data_t o = (st_data_t)obj, id;
-
-    GC_ASSERT(BUILTIN_TYPE(obj) == T_NONE || FL_TEST(obj, FL_SEEN_OBJ_ID));
-    FL_UNSET(obj, FL_SEEN_OBJ_ID);
-
-    if (st_delete(objspace->obj_to_id_tbl, &o, &id)) {
-        GC_ASSERT(id);
-        st_delete(objspace->id_to_obj_tbl, &id, NULL);
-    }
-    else {
-        rb_bug("Object ID seen, but not in mapping table: %s", rb_obj_info(obj));
-    }
-}
-
-typedef int each_obj_callback(void *, void *, size_t, void *);
-typedef int each_page_callback(struct heap_page *, void *);
-
-struct each_obj_data {
-    rb_objspace_t *objspace;
-    bool reenable_incremental;
-
-    each_obj_callback *each_obj_callback;
-    each_page_callback *each_page_callback;
-    void *data;
-
-    struct heap_page **pages[HEAP_COUNT];
-    size_t pages_counts[HEAP_COUNT];
-};
-
-static VALUE
-objspace_each_objects_ensure(VALUE arg)
-{
-    struct each_obj_data *data = (struct each_obj_data *)arg;
-    rb_objspace_t *objspace = data->objspace;
-
-    /* Reenable incremental GC */
-    if (data->reenable_incremental) {
-        objspace->flags.dont_incremental = FALSE;
-    }
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        struct heap_page **pages = data->pages[i];
-        free(pages);
-    }
-
-    return Qnil;
-}
-
-static VALUE
-objspace_each_objects_try(VALUE arg)
-{
-    struct each_obj_data *data = (struct each_obj_data *)arg;
-    rb_objspace_t *objspace = data->objspace;
-
-    /* Copy pages from all heaps to their respective buffers. */
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        size_t size = heap->total_pages * sizeof(struct heap_page *);
-
-        struct heap_page **pages = malloc(size);
-        if (!pages) rb_memerror();
-
-        /* Set up pages buffer by iterating over all pages in the current eden
-         * heap. This will be a snapshot of the state of the heap before we
-         * call the callback over each page that exists in this buffer. Thus it
-         * is safe for the callback to allocate objects without possibly entering
-         * an infinite loop. */
-        struct heap_page *page = 0;
-        size_t pages_count = 0;
-        ccan_list_for_each(&heap->pages, page, page_node) {
-            pages[pages_count] = page;
-            pages_count++;
-        }
-        data->pages[i] = pages;
-        data->pages_counts[i] = pages_count;
-        GC_ASSERT(pages_count == heap->total_pages);
-    }
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        size_t pages_count = data->pages_counts[i];
-        struct heap_page **pages = data->pages[i];
-
-        struct heap_page *page = ccan_list_top(&heap->pages, struct heap_page, page_node);
-        for (size_t i = 0; i < pages_count; i++) {
-            /* If we have reached the end of the linked list then there are no
-             * more pages, so break. */
-            if (page == NULL) break;
-
-            /* If this page does not match the one in the buffer, then move to
-             * the next page in the buffer. */
-            if (pages[i] != page) continue;
-
-            uintptr_t pstart = (uintptr_t)page->start;
-            uintptr_t pend = pstart + (page->total_slots * heap->slot_size);
-
-            if (data->each_obj_callback &&
-                (*data->each_obj_callback)((void *)pstart, (void *)pend, heap->slot_size, data->data)) {
-                break;
-            }
-            if (data->each_page_callback &&
-                (*data->each_page_callback)(page, data->data)) {
-                break;
-            }
-
-            page = ccan_list_next(&heap->pages, page, page_node);
-        }
-    }
-
-    return Qnil;
-}
-
-static void
-objspace_each_exec(bool protected, struct each_obj_data *each_obj_data)
-{
-    /* Disable incremental GC */
-    rb_objspace_t *objspace = each_obj_data->objspace;
-    bool reenable_incremental = FALSE;
-    if (protected) {
-        reenable_incremental = !objspace->flags.dont_incremental;
-
-        gc_rest(objspace);
-        objspace->flags.dont_incremental = TRUE;
-    }
-
-    each_obj_data->reenable_incremental = reenable_incremental;
-    memset(&each_obj_data->pages, 0, sizeof(each_obj_data->pages));
-    memset(&each_obj_data->pages_counts, 0, sizeof(each_obj_data->pages_counts));
-    rb_ensure(objspace_each_objects_try, (VALUE)each_obj_data,
-              objspace_each_objects_ensure, (VALUE)each_obj_data);
-}
-
-static void
-objspace_each_objects(rb_objspace_t *objspace, each_obj_callback *callback, void *data, bool protected)
-{
-    struct each_obj_data each_obj_data = {
-        .objspace = objspace,
-        .each_obj_callback = callback,
-        .each_page_callback = NULL,
-        .data = data,
-    };
-    objspace_each_exec(protected, &each_obj_data);
-}
-
-void
-rb_gc_impl_each_objects(void *objspace_ptr, each_obj_callback *callback, void *data)
-{
-    objspace_each_objects(objspace_ptr, callback, data, TRUE);
-}
-
-#if GC_CAN_COMPILE_COMPACTION
-static void
-objspace_each_pages(rb_objspace_t *objspace, each_page_callback *callback, void *data, bool protected)
-{
-    struct each_obj_data each_obj_data = {
-        .objspace = objspace,
-        .each_obj_callback = NULL,
-        .each_page_callback = callback,
-        .data = data,
-    };
-    objspace_each_exec(protected, &each_obj_data);
-}
-#endif
-
-VALUE
-rb_gc_impl_define_finalizer(void *objspace_ptr, VALUE obj, VALUE block)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    VALUE table;
-    st_data_t data;
-
-    GC_ASSERT(!OBJ_FROZEN(obj));
-
-    RBASIC(obj)->flags |= FL_FINALIZE;
-
-    if (st_lookup(finalizer_table, obj, &data)) {
-        table = (VALUE)data;
-
-        /* avoid duplicate block, table is usually small */
-        {
-            long len = RARRAY_LEN(table);
-            long i;
-
-            for (i = 0; i < len; i++) {
-                VALUE recv = RARRAY_AREF(table, i);
-                if (rb_equal(recv, block)) {
-                    return recv;
-                }
-            }
-        }
-
-        rb_ary_push(table, block);
-    }
-    else {
-        table = rb_ary_new3(1, block);
-        rb_obj_hide(table);
-        st_add_direct(finalizer_table, obj, table);
-    }
-
-    return block;
-}
-
-void
-rb_gc_impl_undefine_finalizer(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    GC_ASSERT(!OBJ_FROZEN(obj));
-
-    st_data_t data = obj;
-    st_delete(finalizer_table, &data, 0);
-    FL_UNSET(obj, FL_FINALIZE);
-}
-
-void
-rb_gc_impl_copy_finalizer(void *objspace_ptr, VALUE dest, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    VALUE table;
-    st_data_t data;
-
-    if (!FL_TEST(obj, FL_FINALIZE)) return;
-
-    if (RB_LIKELY(st_lookup(finalizer_table, obj, &data))) {
-        table = (VALUE)data;
-        st_insert(finalizer_table, dest, table);
-        FL_SET(dest, FL_FINALIZE);
-    }
-    else {
-        rb_bug("rb_gc_copy_finalizer: FL_FINALIZE set but not found in finalizer_table: %s", rb_obj_info(obj));
-    }
-}
-
-static VALUE
-get_object_id_in_finalizer(rb_objspace_t *objspace, VALUE obj)
-{
-    if (FL_TEST(obj, FL_SEEN_OBJ_ID)) {
-        return rb_gc_impl_object_id(objspace, obj);
-    }
-    else {
-        VALUE id = ULL2NUM(objspace->next_object_id);
-        objspace->next_object_id += OBJ_ID_INCREMENT;
-        return id;
-    }
-}
-
-static VALUE
-get_final(long i, void *data)
-{
-    VALUE table = (VALUE)data;
-
-    return RARRAY_AREF(table, i);
-}
-
-static void
-run_final(rb_objspace_t *objspace, VALUE zombie)
-{
-    if (RZOMBIE(zombie)->dfree) {
-        RZOMBIE(zombie)->dfree(RZOMBIE(zombie)->data);
-    }
-
-    st_data_t key = (st_data_t)zombie;
-    if (FL_TEST_RAW(zombie, FL_FINALIZE)) {
-        FL_UNSET(zombie, FL_FINALIZE);
-        st_data_t table;
-        if (st_delete(finalizer_table, &key, &table)) {
-            rb_gc_run_obj_finalizer(get_object_id_in_finalizer(objspace, zombie), RARRAY_LEN(table), get_final, (void *)table);
-        }
-        else {
-            rb_bug("FL_FINALIZE flag is set, but finalizers are not found");
-        }
-    }
-    else {
-        GC_ASSERT(!st_lookup(finalizer_table, key, NULL));
-    }
-}
-
-static void
-finalize_list(rb_objspace_t *objspace, VALUE zombie)
-{
-    while (zombie) {
-        VALUE next_zombie;
-        struct heap_page *page;
-        asan_unpoison_object(zombie, false);
-        next_zombie = RZOMBIE(zombie)->next;
-        page = GET_HEAP_PAGE(zombie);
-
-        run_final(objspace, zombie);
-
-        int lev = rb_gc_vm_lock();
-        {
-            GC_ASSERT(BUILTIN_TYPE(zombie) == T_ZOMBIE);
-            if (FL_TEST(zombie, FL_SEEN_OBJ_ID)) {
-                obj_free_object_id(objspace, zombie);
-            }
-
-            GC_ASSERT(page->heap->final_slots_count > 0);
-            GC_ASSERT(page->final_slots > 0);
-
-            page->heap->final_slots_count--;
-            page->final_slots--;
-            page->free_slots++;
-            heap_page_add_freeobj(objspace, page, zombie);
-            page->heap->total_freed_objects++;
-        }
-        rb_gc_vm_unlock(lev);
-
-        zombie = next_zombie;
-    }
-}
-
-static void
-finalize_deferred_heap_pages(rb_objspace_t *objspace)
-{
-    VALUE zombie;
-    while ((zombie = RUBY_ATOMIC_VALUE_EXCHANGE(heap_pages_deferred_final, 0)) != 0) {
-        finalize_list(objspace, zombie);
-    }
-}
-
-static void
-finalize_deferred(rb_objspace_t *objspace)
-{
-    rb_gc_set_pending_interrupt();
-    finalize_deferred_heap_pages(objspace);
-    rb_gc_unset_pending_interrupt();
-}
-
-static void
-gc_finalize_deferred(void *dmy)
-{
-    rb_objspace_t *objspace = dmy;
-    if (RUBY_ATOMIC_EXCHANGE(finalizing, 1)) return;
-
-    finalize_deferred(objspace);
-    RUBY_ATOMIC_SET(finalizing, 0);
-}
-
-static void
-gc_finalize_deferred_register(rb_objspace_t *objspace)
-{
-    /* will enqueue a call to gc_finalize_deferred */
-    rb_postponed_job_trigger(objspace->finalize_deferred_pjob);
-}
-
-static int pop_mark_stack(mark_stack_t *stack, VALUE *data);
-
-static void
-gc_abort(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (is_incremental_marking(objspace)) {
-        /* Remove all objects from the mark stack. */
-        VALUE obj;
-        while (pop_mark_stack(&objspace->mark_stack, &obj));
-
-        objspace->flags.during_incremental_marking = FALSE;
-    }
-
-    if (is_lazy_sweeping(objspace)) {
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rb_heap_t *heap = &heaps[i];
-
-            heap->sweeping_page = NULL;
-            struct heap_page *page = NULL;
-
-            ccan_list_for_each(&heap->pages, page, page_node) {
-                page->flags.before_sweep = false;
-            }
-        }
-    }
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        rgengc_mark_and_rememberset_clear(objspace, heap);
-    }
-
-    gc_mode_set(objspace, gc_mode_none);
-}
-
-void
-rb_gc_impl_shutdown_free_objects(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    for (size_t i = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-        struct heap_page *page = rb_darray_get(objspace->heap_pages.sorted, i);
-        short stride = page->slot_size;
-
-        uintptr_t p = (uintptr_t)page->start;
-        uintptr_t pend = p + page->total_slots * stride;
-        for (; p < pend; p += stride) {
-            VALUE vp = (VALUE)p;
-            asan_unpoisoning_object(vp) {
-                if (RB_BUILTIN_TYPE(vp) != T_NONE) {
-                    if (rb_gc_obj_free(objspace, vp)) {
-                        RBASIC(vp)->flags = 0;
-                    }
-                }
-            }
-        }
-    }
-}
-
-static int
-rb_gc_impl_shutdown_call_finalizer_i(st_data_t key, st_data_t val, st_data_t data)
-{
-    rb_objspace_t *objspace = (rb_objspace_t *)data;
-    VALUE obj = (VALUE)key;
-    VALUE table = (VALUE)val;
-
-    GC_ASSERT(RB_FL_TEST(obj, FL_FINALIZE));
-    GC_ASSERT(RB_BUILTIN_TYPE(val) == T_ARRAY);
-
-    rb_gc_run_obj_finalizer(rb_gc_impl_object_id(objspace, obj), RARRAY_LEN(table), get_final, (void *)table);
-
-    FL_UNSET(obj, FL_FINALIZE);
-
-    return ST_DELETE;
-}
-
-void
-rb_gc_impl_shutdown_call_finalizer(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-
-    /* prohibit incremental GC */
-    objspace->flags.dont_incremental = 1;
-
-    if (RUBY_ATOMIC_EXCHANGE(finalizing, 1)) {
-        /* Abort incremental marking and lazy sweeping to speed up shutdown. */
-        gc_abort(objspace);
-        dont_gc_on();
-        return;
-    }
-
-    while (finalizer_table->num_entries) {
-        st_foreach(finalizer_table, rb_gc_impl_shutdown_call_finalizer_i, (st_data_t)objspace);
-    }
-
-    /* run finalizers */
-    finalize_deferred(objspace);
-    GC_ASSERT(heap_pages_deferred_final == 0);
-
-    /* Abort incremental marking and lazy sweeping to speed up shutdown. */
-    gc_abort(objspace);
-
-    /* prohibit GC because force T_DATA finalizers can break an object graph consistency */
-    dont_gc_on();
-
-    /* running data/file finalizers are part of garbage collection */
-    unsigned int lock_lev;
-    gc_enter(objspace, gc_enter_event_finalizer, &lock_lev);
-
-    /* run data/file object's finalizers */
-    for (size_t i = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-        struct heap_page *page = rb_darray_get(objspace->heap_pages.sorted, i);
-        short stride = page->slot_size;
-
-        uintptr_t p = (uintptr_t)page->start;
-        uintptr_t pend = p + page->total_slots * stride;
-        for (; p < pend; p += stride) {
-            VALUE vp = (VALUE)p;
-            asan_unpoisoning_object(vp) {
-                if (rb_gc_shutdown_call_finalizer_p(vp)) {
-                    if (rb_gc_obj_free(objspace, vp)) {
-                        RBASIC(vp)->flags = 0;
-                    }
-                }
-            }
-        }
-    }
-
-    gc_exit(objspace, gc_enter_event_finalizer, &lock_lev);
-
-    finalize_deferred_heap_pages(objspace);
-
-    st_free_table(finalizer_table);
-    finalizer_table = 0;
-    RUBY_ATOMIC_SET(finalizing, 0);
-}
-
-void
-rb_gc_impl_each_object(void *objspace_ptr, void (*func)(VALUE obj, void *data), void *data)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    for (size_t i = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-        struct heap_page *page = rb_darray_get(objspace->heap_pages.sorted, i);
-        short stride = page->slot_size;
-
-        uintptr_t p = (uintptr_t)page->start;
-        uintptr_t pend = p + page->total_slots * stride;
-        for (; p < pend; p += stride) {
-            VALUE obj = (VALUE)p;
-
-            asan_unpoisoning_object(obj) {
-                func(obj, data);
-            }
-        }
-    }
-}
-
-/*
-  ------------------------ Garbage Collection ------------------------
-*/
-
-/* Sweeping */
-
-static size_t
-objspace_available_slots(rb_objspace_t *objspace)
-{
-    size_t total_slots = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        total_slots += heap->total_slots;
-    }
-    return total_slots;
-}
-
-static size_t
-objspace_live_slots(rb_objspace_t *objspace)
-{
-    return total_allocated_objects(objspace) - total_freed_objects(objspace) - total_final_slots_count(objspace);
-}
-
-static size_t
-objspace_free_slots(rb_objspace_t *objspace)
-{
-    return objspace_available_slots(objspace) - objspace_live_slots(objspace) - total_final_slots_count(objspace);
-}
-
-static void
-gc_setup_mark_bits(struct heap_page *page)
-{
-    /* copy oldgen bitmap to mark bitmap */
-    memcpy(&page->mark_bits[0], &page->uncollectible_bits[0], HEAP_PAGE_BITMAP_SIZE);
-}
-
-static int gc_is_moveable_obj(rb_objspace_t *objspace, VALUE obj);
-static VALUE gc_move(rb_objspace_t *objspace, VALUE scan, VALUE free, size_t src_slot_size, size_t slot_size);
-
-#if defined(_WIN32)
-enum {HEAP_PAGE_LOCK = PAGE_NOACCESS, HEAP_PAGE_UNLOCK = PAGE_READWRITE};
-
-static BOOL
-protect_page_body(struct heap_page_body *body, DWORD protect)
-{
-    DWORD old_protect;
-    return VirtualProtect(body, HEAP_PAGE_SIZE, protect, &old_protect) != 0;
-}
-#else
-enum {HEAP_PAGE_LOCK = PROT_NONE, HEAP_PAGE_UNLOCK = PROT_READ | PROT_WRITE};
-#define protect_page_body(body, protect) !mprotect((body), HEAP_PAGE_SIZE, (protect))
-#endif
-
-static void
-lock_page_body(rb_objspace_t *objspace, struct heap_page_body *body)
-{
-    if (!protect_page_body(body, HEAP_PAGE_LOCK)) {
-        rb_bug("Couldn't protect page %p, errno: %s", (void *)body, strerror(errno));
-    }
-    else {
-        gc_report(5, objspace, "Protecting page in move %p\n", (void *)body);
-    }
-}
-
-static void
-unlock_page_body(rb_objspace_t *objspace, struct heap_page_body *body)
-{
-    if (!protect_page_body(body, HEAP_PAGE_UNLOCK)) {
-        rb_bug("Couldn't unprotect page %p, errno: %s", (void *)body, strerror(errno));
-    }
-    else {
-        gc_report(5, objspace, "Unprotecting page in move %p\n", (void *)body);
-    }
-}
-
-static bool
-try_move(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *free_page, VALUE src)
-{
-    GC_ASSERT(gc_is_moveable_obj(objspace, src));
-
-    struct heap_page *src_page = GET_HEAP_PAGE(src);
-    if (!free_page) {
-        return false;
-    }
-
-    /* We should return true if either src is successfully moved, or src is
-     * unmoveable. A false return will cause the sweeping cursor to be
-     * incremented to the next page, and src will attempt to move again */
-    GC_ASSERT(RVALUE_MARKED(objspace, src));
-
-    asan_unlock_freelist(free_page);
-    VALUE dest = (VALUE)free_page->freelist;
-    asan_lock_freelist(free_page);
-    asan_unpoison_object(dest, false);
-    if (!dest) {
-        /* if we can't get something from the freelist then the page must be
-         * full */
-        return false;
-    }
-    asan_unlock_freelist(free_page);
-    free_page->freelist = ((struct free_slot *)dest)->next;
-    asan_lock_freelist(free_page);
-
-    GC_ASSERT(RB_BUILTIN_TYPE(dest) == T_NONE);
-
-    if (src_page->slot_size > free_page->slot_size) {
-        objspace->rcompactor.moved_down_count_table[BUILTIN_TYPE(src)]++;
-    }
-    else if (free_page->slot_size > src_page->slot_size) {
-        objspace->rcompactor.moved_up_count_table[BUILTIN_TYPE(src)]++;
-    }
-    objspace->rcompactor.moved_count_table[BUILTIN_TYPE(src)]++;
-    objspace->rcompactor.total_moved++;
-
-    gc_move(objspace, src, dest, src_page->slot_size, free_page->slot_size);
-    gc_pin(objspace, src);
-    free_page->free_slots--;
-
-    return true;
-}
-
-static void
-gc_unprotect_pages(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    struct heap_page *cursor = heap->compact_cursor;
-
-    while (cursor) {
-        unlock_page_body(objspace, cursor->body);
-        cursor = ccan_list_next(&heap->pages, cursor, page_node);
-    }
-}
-
-static void gc_update_references(rb_objspace_t *objspace);
-#if GC_CAN_COMPILE_COMPACTION
-static void invalidate_moved_page(rb_objspace_t *objspace, struct heap_page *page);
-#endif
-
-#if defined(__MINGW32__) || defined(_WIN32)
-# define GC_COMPACTION_SUPPORTED 1
-#else
-/* If not MinGW, Windows, or does not have mmap, we cannot use mprotect for
- * the read barrier, so we must disable compaction. */
-# define GC_COMPACTION_SUPPORTED (GC_CAN_COMPILE_COMPACTION && HEAP_PAGE_ALLOC_USE_MMAP)
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-static void
-read_barrier_handler(uintptr_t original_address)
-{
-    VALUE obj;
-    rb_objspace_t *objspace = (rb_objspace_t *)rb_gc_get_objspace();
-
-    /* Calculate address aligned to slots. */
-    uintptr_t address = original_address - (original_address % BASE_SLOT_SIZE);
-
-    obj = (VALUE)address;
-
-    struct heap_page_body *page_body = GET_PAGE_BODY(obj);
-
-    /* If the page_body is NULL, then mprotect cannot handle it and will crash
-     * with "Cannot allocate memory". */
-    if (page_body == NULL) {
-        rb_bug("read_barrier_handler: segmentation fault at %p", (void *)original_address);
-    }
-
-    int lev = rb_gc_vm_lock();
-    {
-        unlock_page_body(objspace, page_body);
-
-        objspace->profile.read_barrier_faults++;
-
-        invalidate_moved_page(objspace, GET_HEAP_PAGE(obj));
-    }
-    rb_gc_vm_unlock(lev);
-}
-#endif
-
-#if !GC_CAN_COMPILE_COMPACTION
-static void
-uninstall_handlers(void)
-{
-    /* no-op */
-}
-
-static void
-install_handlers(void)
-{
-    /* no-op */
-}
-#elif defined(_WIN32)
-static LPTOP_LEVEL_EXCEPTION_FILTER old_handler;
-typedef void (*signal_handler)(int);
-static signal_handler old_sigsegv_handler;
-
-static LONG WINAPI
-read_barrier_signal(EXCEPTION_POINTERS *info)
-{
-    /* EXCEPTION_ACCESS_VIOLATION is what's raised by access to protected pages */
-    if (info->ExceptionRecord->ExceptionCode == EXCEPTION_ACCESS_VIOLATION) {
-        /* > The second array element specifies the virtual address of the inaccessible data.
-         * https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-exception_record
-         *
-         * Use this address to invalidate the page */
-        read_barrier_handler((uintptr_t)info->ExceptionRecord->ExceptionInformation[1]);
-        return EXCEPTION_CONTINUE_EXECUTION;
-    }
-    else {
-        return EXCEPTION_CONTINUE_SEARCH;
-    }
-}
-
-static void
-uninstall_handlers(void)
-{
-    signal(SIGSEGV, old_sigsegv_handler);
-    SetUnhandledExceptionFilter(old_handler);
-}
-
-static void
-install_handlers(void)
-{
-    /* Remove SEGV handler so that the Unhandled Exception Filter handles it */
-    old_sigsegv_handler = signal(SIGSEGV, NULL);
-    /* Unhandled Exception Filter has access to the violation address similar
-     * to si_addr from sigaction */
-    old_handler = SetUnhandledExceptionFilter(read_barrier_signal);
-}
-#else
-static struct sigaction old_sigbus_handler;
-static struct sigaction old_sigsegv_handler;
-
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-static exception_mask_t old_exception_masks[32];
-static mach_port_t old_exception_ports[32];
-static exception_behavior_t old_exception_behaviors[32];
-static thread_state_flavor_t old_exception_flavors[32];
-static mach_msg_type_number_t old_exception_count;
-
-static void
-disable_mach_bad_access_exc(void)
-{
-    old_exception_count = sizeof(old_exception_masks) / sizeof(old_exception_masks[0]);
-    task_swap_exception_ports(
-        mach_task_self(), EXC_MASK_BAD_ACCESS,
-        MACH_PORT_NULL, EXCEPTION_DEFAULT, 0,
-        old_exception_masks, &old_exception_count,
-        old_exception_ports, old_exception_behaviors, old_exception_flavors
-    );
-}
-
-static void
-restore_mach_bad_access_exc(void)
-{
-    for (mach_msg_type_number_t i = 0; i < old_exception_count; i++) {
-        task_set_exception_ports(
-            mach_task_self(),
-            old_exception_masks[i], old_exception_ports[i],
-            old_exception_behaviors[i], old_exception_flavors[i]
-        );
-    }
-}
-#endif
-
-static void
-read_barrier_signal(int sig, siginfo_t *info, void *data)
-{
-    // setup SEGV/BUS handlers for errors
-    struct sigaction prev_sigbus, prev_sigsegv;
-    sigaction(SIGBUS, &old_sigbus_handler, &prev_sigbus);
-    sigaction(SIGSEGV, &old_sigsegv_handler, &prev_sigsegv);
-
-    // enable SIGBUS/SEGV
-    sigset_t set, prev_set;
-    sigemptyset(&set);
-    sigaddset(&set, SIGBUS);
-    sigaddset(&set, SIGSEGV);
-    sigprocmask(SIG_UNBLOCK, &set, &prev_set);
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-    disable_mach_bad_access_exc();
-#endif
-    // run handler
-    read_barrier_handler((uintptr_t)info->si_addr);
-
-    // reset SEGV/BUS handlers
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-    restore_mach_bad_access_exc();
-#endif
-    sigaction(SIGBUS, &prev_sigbus, NULL);
-    sigaction(SIGSEGV, &prev_sigsegv, NULL);
-    sigprocmask(SIG_SETMASK, &prev_set, NULL);
-}
-
-static void
-uninstall_handlers(void)
-{
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-    restore_mach_bad_access_exc();
-#endif
-    sigaction(SIGBUS, &old_sigbus_handler, NULL);
-    sigaction(SIGSEGV, &old_sigsegv_handler, NULL);
-}
-
-static void
-install_handlers(void)
-{
-    struct sigaction action;
-    memset(&action, 0, sizeof(struct sigaction));
-    sigemptyset(&action.sa_mask);
-    action.sa_sigaction = read_barrier_signal;
-    action.sa_flags = SA_SIGINFO | SA_ONSTACK;
-
-    sigaction(SIGBUS, &action, &old_sigbus_handler);
-    sigaction(SIGSEGV, &action, &old_sigsegv_handler);
-#ifdef HAVE_MACH_TASK_EXCEPTION_PORTS
-    disable_mach_bad_access_exc();
-#endif
-}
-#endif
-
-static void
-gc_compact_finish(rb_objspace_t *objspace)
-{
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        gc_unprotect_pages(objspace, heap);
-    }
-
-    uninstall_handlers();
-
-    gc_update_references(objspace);
-    objspace->profile.compact_count++;
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        heap->compact_cursor = NULL;
-        heap->free_pages = NULL;
-        heap->compact_cursor_index = 0;
-    }
-
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->moved_objects = objspace->rcompactor.total_moved - record->moved_objects;
-    }
-    objspace->flags.during_compacting = FALSE;
-}
-
-struct gc_sweep_context {
-    struct heap_page *page;
-    int final_slots;
-    int freed_slots;
-    int empty_slots;
-};
-
-static inline void
-gc_sweep_plane(rb_objspace_t *objspace, rb_heap_t *heap, uintptr_t p, bits_t bitset, struct gc_sweep_context *ctx)
-{
-    struct heap_page *sweep_page = ctx->page;
-    short slot_size = sweep_page->slot_size;
-    short slot_bits = slot_size / BASE_SLOT_SIZE;
-    GC_ASSERT(slot_bits > 0);
-
-    do {
-        VALUE vp = (VALUE)p;
-        GC_ASSERT(vp % BASE_SLOT_SIZE == 0);
-
-        asan_unpoison_object(vp, false);
-        if (bitset & 1) {
-            switch (BUILTIN_TYPE(vp)) {
-              default: /* majority case */
-                gc_report(2, objspace, "page_sweep: free %p\n", (void *)p);
-#if RGENGC_CHECK_MODE
-                if (!is_full_marking(objspace)) {
-                    if (RVALUE_OLD_P(objspace, vp)) rb_bug("page_sweep: %p - old while minor GC.", (void *)p);
-                    if (RVALUE_REMEMBERED(objspace, vp)) rb_bug("page_sweep: %p - remembered.", (void *)p);
-                }
-#endif
-
-                if (RVALUE_WB_UNPROTECTED(objspace, vp)) CLEAR_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(vp), vp);
-
-#if RGENGC_CHECK_MODE
-#define CHECK(x) if (x(objspace, vp) != FALSE) rb_bug("obj_free: " #x "(%s) != FALSE", rb_obj_info(vp))
-                CHECK(RVALUE_WB_UNPROTECTED);
-                CHECK(RVALUE_MARKED);
-                CHECK(RVALUE_MARKING);
-                CHECK(RVALUE_UNCOLLECTIBLE);
-#undef CHECK
-#endif
-
-                rb_gc_event_hook(vp, RUBY_INTERNAL_EVENT_FREEOBJ);
-
-                bool has_object_id = FL_TEST(vp, FL_SEEN_OBJ_ID);
-                if (rb_gc_obj_free(objspace, vp)) {
-                    if (has_object_id) {
-                        obj_free_object_id(objspace, vp);
-                    }
-                    // always add free slots back to the swept pages freelist,
-                    // so that if we're compacting, we can re-use the slots
-                    (void)VALGRIND_MAKE_MEM_UNDEFINED((void*)p, BASE_SLOT_SIZE);
-                    heap_page_add_freeobj(objspace, sweep_page, vp);
-                    gc_report(3, objspace, "page_sweep: %s is added to freelist\n", rb_obj_info(vp));
-                    ctx->freed_slots++;
-                }
-                else {
-                    ctx->final_slots++;
-                }
-                break;
-
-              case T_MOVED:
-                if (objspace->flags.during_compacting) {
-                    /* The sweep cursor shouldn't have made it to any
-                     * T_MOVED slots while the compact flag is enabled.
-                     * The sweep cursor and compact cursor move in
-                     * opposite directions, and when they meet references will
-                     * get updated and "during_compacting" should get disabled */
-                    rb_bug("T_MOVED shouldn't be seen until compaction is finished");
-                }
-                gc_report(3, objspace, "page_sweep: %s is added to freelist\n", rb_obj_info(vp));
-                ctx->empty_slots++;
-                heap_page_add_freeobj(objspace, sweep_page, vp);
-                break;
-              case T_ZOMBIE:
-                /* already counted */
-                break;
-              case T_NONE:
-                ctx->empty_slots++; /* already freed */
-                break;
-            }
-        }
-        p += slot_size;
-        bitset >>= slot_bits;
-    } while (bitset);
-}
-
-static inline void
-gc_sweep_page(rb_objspace_t *objspace, rb_heap_t *heap, struct gc_sweep_context *ctx)
-{
-    struct heap_page *sweep_page = ctx->page;
-    GC_ASSERT(sweep_page->heap == heap);
-
-    uintptr_t p;
-    bits_t *bits, bitset;
-
-    gc_report(2, objspace, "page_sweep: start.\n");
-
-#if RGENGC_CHECK_MODE
-    if (!objspace->flags.immediate_sweep) {
-        GC_ASSERT(sweep_page->flags.before_sweep == TRUE);
-    }
-#endif
-    sweep_page->flags.before_sweep = FALSE;
-    sweep_page->free_slots = 0;
-
-    p = (uintptr_t)sweep_page->start;
-    bits = sweep_page->mark_bits;
-
-    int page_rvalue_count = sweep_page->total_slots * (sweep_page->slot_size / BASE_SLOT_SIZE);
-    int out_of_range_bits = (NUM_IN_PAGE(p) + page_rvalue_count) % BITS_BITLENGTH;
-    if (out_of_range_bits != 0) { // sizeof(RVALUE) == 64
-        bits[BITMAP_INDEX(p) + page_rvalue_count / BITS_BITLENGTH] |= ~(((bits_t)1 << out_of_range_bits) - 1);
-    }
-
-    /* The last bitmap plane may not be used if the last plane does not
-     * have enough space for the slot_size. In that case, the last plane must
-     * be skipped since none of the bits will be set. */
-    int bitmap_plane_count = CEILDIV(NUM_IN_PAGE(p) + page_rvalue_count, BITS_BITLENGTH);
-    GC_ASSERT(bitmap_plane_count == HEAP_PAGE_BITMAP_LIMIT - 1 ||
-                  bitmap_plane_count == HEAP_PAGE_BITMAP_LIMIT);
-
-    // Skip out of range slots at the head of the page
-    bitset = ~bits[0];
-    bitset >>= NUM_IN_PAGE(p);
-    if (bitset) {
-        gc_sweep_plane(objspace, heap, p, bitset, ctx);
-    }
-    p += (BITS_BITLENGTH - NUM_IN_PAGE(p)) * BASE_SLOT_SIZE;
-
-    for (int i = 1; i < bitmap_plane_count; i++) {
-        bitset = ~bits[i];
-        if (bitset) {
-            gc_sweep_plane(objspace, heap, p, bitset, ctx);
-        }
-        p += BITS_BITLENGTH * BASE_SLOT_SIZE;
-    }
-
-    if (!heap->compact_cursor) {
-        gc_setup_mark_bits(sweep_page);
-    }
-
-#if GC_PROFILE_MORE_DETAIL
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->removing_objects += ctx->final_slots + ctx->freed_slots;
-        record->empty_objects += ctx->empty_slots;
-    }
-#endif
-    if (0) fprintf(stderr, "gc_sweep_page(%"PRIdSIZE"): total_slots: %d, freed_slots: %d, empty_slots: %d, final_slots: %d\n",
-                   rb_gc_count(),
-                   sweep_page->total_slots,
-                   ctx->freed_slots, ctx->empty_slots, ctx->final_slots);
-
-    sweep_page->free_slots += ctx->freed_slots + ctx->empty_slots;
-    sweep_page->heap->total_freed_objects += ctx->freed_slots;
-
-    if (heap_pages_deferred_final && !finalizing) {
-        gc_finalize_deferred_register(objspace);
-    }
-
-#if RGENGC_CHECK_MODE
-    short freelist_len = 0;
-    asan_unlock_freelist(sweep_page);
-    struct free_slot *ptr = sweep_page->freelist;
-    while (ptr) {
-        freelist_len++;
-        ptr = ptr->next;
-    }
-    asan_lock_freelist(sweep_page);
-    if (freelist_len != sweep_page->free_slots) {
-        rb_bug("inconsistent freelist length: expected %d but was %d", sweep_page->free_slots, freelist_len);
-    }
-#endif
-
-    gc_report(2, objspace, "page_sweep: end.\n");
-}
-
-static const char *
-gc_mode_name(enum gc_mode mode)
-{
-    switch (mode) {
-      case gc_mode_none: return "none";
-      case gc_mode_marking: return "marking";
-      case gc_mode_sweeping: return "sweeping";
-      case gc_mode_compacting: return "compacting";
-      default: rb_bug("gc_mode_name: unknown mode: %d", (int)mode);
-    }
-}
-
-static void
-gc_mode_transition(rb_objspace_t *objspace, enum gc_mode mode)
-{
-#if RGENGC_CHECK_MODE
-    enum gc_mode prev_mode = gc_mode(objspace);
-    switch (prev_mode) {
-      case gc_mode_none:     GC_ASSERT(mode == gc_mode_marking); break;
-      case gc_mode_marking:  GC_ASSERT(mode == gc_mode_sweeping); break;
-      case gc_mode_sweeping: GC_ASSERT(mode == gc_mode_none || mode == gc_mode_compacting); break;
-      case gc_mode_compacting: GC_ASSERT(mode == gc_mode_none); break;
-    }
-#endif
-    if (0) fprintf(stderr, "gc_mode_transition: %s->%s\n", gc_mode_name(gc_mode(objspace)), gc_mode_name(mode));
-    gc_mode_set(objspace, mode);
-}
-
-static void
-heap_page_freelist_append(struct heap_page *page, struct free_slot *freelist)
-{
-    if (freelist) {
-        asan_unlock_freelist(page);
-        if (page->freelist) {
-            struct free_slot *p = page->freelist;
-            asan_unpoison_object((VALUE)p, false);
-            while (p->next) {
-                struct free_slot *prev = p;
-                p = p->next;
-                asan_poison_object((VALUE)prev);
-                asan_unpoison_object((VALUE)p, false);
-            }
-            p->next = freelist;
-            asan_poison_object((VALUE)p);
-        }
-        else {
-            page->freelist = freelist;
-        }
-        asan_lock_freelist(page);
-    }
-}
-
-static void
-gc_sweep_start_heap(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    heap->sweeping_page = ccan_list_top(&heap->pages, struct heap_page, page_node);
-    heap->free_pages = NULL;
-    heap->pooled_pages = NULL;
-    if (!objspace->flags.immediate_sweep) {
-        struct heap_page *page = NULL;
-
-        ccan_list_for_each(&heap->pages, page, page_node) {
-            page->flags.before_sweep = TRUE;
-        }
-    }
-}
-
-#if defined(__GNUC__) && __GNUC__ == 4 && __GNUC_MINOR__ == 4
-__attribute__((noinline))
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-static void gc_sort_heap_by_compare_func(rb_objspace_t *objspace, gc_compact_compare_func compare_func);
-static int compare_pinned_slots(const void *left, const void *right, void *d);
-#endif
-
-static void
-gc_ractor_newobj_cache_clear(void *c, void *data)
-{
-    rb_ractor_newobj_cache_t *newobj_cache = c;
-
-    newobj_cache->incremental_mark_step_allocated_slots = 0;
-
-    for (size_t heap_idx = 0; heap_idx < HEAP_COUNT; heap_idx++) {
-        rb_ractor_newobj_heap_cache_t *cache = &newobj_cache->heap_caches[heap_idx];
-
-        struct heap_page *page = cache->using_page;
-        struct free_slot *freelist = cache->freelist;
-        RUBY_DEBUG_LOG("ractor using_page:%p freelist:%p", (void *)page, (void *)freelist);
-
-        heap_page_freelist_append(page, freelist);
-
-        cache->using_page = NULL;
-        cache->freelist = NULL;
-    }
-}
-
-static void
-gc_sweep_start(rb_objspace_t *objspace)
-{
-    gc_mode_transition(objspace, gc_mode_sweeping);
-    objspace->rincgc.pooled_slots = 0;
-    objspace->heap_pages.allocatable_slots = 0;
-
-#if GC_CAN_COMPILE_COMPACTION
-    if (objspace->flags.during_compacting) {
-        gc_sort_heap_by_compare_func(
-            objspace,
-            objspace->rcompactor.compare_func ? objspace->rcompactor.compare_func : compare_pinned_slots
-        );
-    }
-#endif
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        gc_sweep_start_heap(objspace, heap);
-
-        /* We should call gc_sweep_finish_heap for size pools with no pages. */
-        if (heap->sweeping_page == NULL) {
-            GC_ASSERT(heap->total_pages == 0);
-            GC_ASSERT(heap->total_slots == 0);
-            gc_sweep_finish_heap(objspace, heap);
-        }
-    }
-
-    rb_gc_ractor_newobj_cache_foreach(gc_ractor_newobj_cache_clear, NULL);
-}
-
-static void
-gc_sweep_finish_heap(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    size_t total_slots = heap->total_slots;
-    size_t swept_slots = heap->freed_slots + heap->empty_slots;
-
-    size_t init_slots = gc_params.heap_init_slots[heap - heaps];
-    size_t min_free_slots = (size_t)(MAX(total_slots, init_slots) * gc_params.heap_free_slots_min_ratio);
-
-    if (swept_slots < min_free_slots &&
-            /* The heap is a growth heap if it freed more slots than had empty slots. */
-            (heap->empty_slots == 0 || heap->freed_slots > heap->empty_slots)) {
-        /* If we don't have enough slots and we have pages on the tomb heap, move
-        * pages from the tomb heap to the eden heap. This may prevent page
-        * creation thrashing (frequently allocating and deallocting pages) and
-        * GC thrashing (running GC more frequently than required). */
-        struct heap_page *resurrected_page;
-        while (swept_slots < min_free_slots &&
-                (resurrected_page = heap_page_resurrect(objspace))) {
-            heap_add_page(objspace, heap, resurrected_page);
-            heap_add_freepage(heap, resurrected_page);
-
-            swept_slots += resurrected_page->free_slots;
-        }
-
-        if (swept_slots < min_free_slots) {
-            /* Grow this heap if we are in a major GC or if we haven't run at least
-            * RVALUE_OLD_AGE minor GC since the last major GC. */
-            if (is_full_marking(objspace) ||
-                    objspace->profile.count - objspace->rgengc.last_major_gc < RVALUE_OLD_AGE) {
-                heap_allocatable_slots_expand(objspace, heap, swept_slots, heap->total_slots);
-            }
-            else {
-                gc_needs_major_flags |= GPR_FLAG_MAJOR_BY_NOFREE;
-                heap->force_major_gc_count++;
-            }
-        }
-    }
-}
-
-static void
-gc_sweep_finish(rb_objspace_t *objspace)
-{
-    gc_report(1, objspace, "gc_sweep_finish\n");
-
-    gc_prof_set_heap_info(objspace);
-    heap_pages_free_unused_pages(objspace);
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-
-        heap->freed_slots = 0;
-        heap->empty_slots = 0;
-
-        if (!will_be_incremental_marking(objspace)) {
-            struct heap_page *end_page = heap->free_pages;
-            if (end_page) {
-                while (end_page->free_next) end_page = end_page->free_next;
-                end_page->free_next = heap->pooled_pages;
-            }
-            else {
-                heap->free_pages = heap->pooled_pages;
-            }
-            heap->pooled_pages = NULL;
-            objspace->rincgc.pooled_slots = 0;
-        }
-    }
-
-    rb_gc_event_hook(0, RUBY_INTERNAL_EVENT_GC_END_SWEEP);
-    gc_mode_transition(objspace, gc_mode_none);
-
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-}
-
-static int
-gc_sweep_step(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    struct heap_page *sweep_page = heap->sweeping_page;
-    int unlink_limit = GC_SWEEP_PAGES_FREEABLE_PER_STEP;
-    int swept_slots = 0;
-    int pooled_slots = 0;
-
-    if (sweep_page == NULL) return FALSE;
-
-#if GC_ENABLE_LAZY_SWEEP
-    gc_prof_sweep_timer_start(objspace);
-#endif
-
-    do {
-        RUBY_DEBUG_LOG("sweep_page:%p", (void *)sweep_page);
-
-        struct gc_sweep_context ctx = {
-            .page = sweep_page,
-            .final_slots = 0,
-            .freed_slots = 0,
-            .empty_slots = 0,
-        };
-        gc_sweep_page(objspace, heap, &ctx);
-        int free_slots = ctx.freed_slots + ctx.empty_slots;
-
-        heap->sweeping_page = ccan_list_next(&heap->pages, sweep_page, page_node);
-
-        if (free_slots == sweep_page->total_slots &&
-                heap_pages_freeable_pages > 0 &&
-                unlink_limit > 0) {
-            heap_pages_freeable_pages--;
-            unlink_limit--;
-            /* There are no living objects, so move this page to the global empty pages. */
-            heap_unlink_page(objspace, heap, sweep_page);
-
-            sweep_page->start = 0;
-            sweep_page->total_slots = 0;
-            sweep_page->slot_size = 0;
-            sweep_page->heap = NULL;
-            sweep_page->free_slots = 0;
-
-            asan_unlock_freelist(sweep_page);
-            sweep_page->freelist = NULL;
-            asan_lock_freelist(sweep_page);
-
-            asan_poison_memory_region(sweep_page->body, HEAP_PAGE_SIZE);
-
-            objspace->empty_pages_count++;
-            sweep_page->free_next = objspace->empty_pages;
-            objspace->empty_pages = sweep_page;
-        }
-        else if (free_slots > 0) {
-            heap->freed_slots += ctx.freed_slots;
-            heap->empty_slots += ctx.empty_slots;
-
-            if (pooled_slots < GC_INCREMENTAL_SWEEP_POOL_SLOT_COUNT) {
-                heap_add_poolpage(objspace, heap, sweep_page);
-                pooled_slots += free_slots;
-            }
-            else {
-                heap_add_freepage(heap, sweep_page);
-                swept_slots += free_slots;
-                if (swept_slots > GC_INCREMENTAL_SWEEP_SLOT_COUNT) {
-                    break;
-                }
-            }
-        }
-        else {
-            sweep_page->free_next = NULL;
-        }
-    } while ((sweep_page = heap->sweeping_page));
-
-    if (!heap->sweeping_page) {
-        gc_sweep_finish_heap(objspace, heap);
-
-        if (!has_sweeping_pages(objspace)) {
-            gc_sweep_finish(objspace);
-        }
-    }
-
-#if GC_ENABLE_LAZY_SWEEP
-    gc_prof_sweep_timer_stop(objspace);
-#endif
-
-    return heap->free_pages != NULL;
-}
-
-static void
-gc_sweep_rest(rb_objspace_t *objspace)
-{
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-
-        while (heap->sweeping_page) {
-            gc_sweep_step(objspace, heap);
-        }
-    }
-}
-
-static void
-gc_sweep_continue(rb_objspace_t *objspace, rb_heap_t *sweep_heap)
-{
-    GC_ASSERT(dont_gc_val() == FALSE || objspace->profile.latest_gc_info & GPR_FLAG_METHOD);
-    if (!GC_ENABLE_LAZY_SWEEP) return;
-
-    gc_sweeping_enter(objspace);
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        if (!gc_sweep_step(objspace, heap)) {
-            /* sweep_heap requires a free slot but sweeping did not yield any
-             * and we cannot allocate a new page. */
-            if (heap == sweep_heap && objspace->heap_pages.allocatable_slots == 0) {
-                /* Not allowed to create a new page so finish sweeping. */
-                gc_sweep_rest(objspace);
-                break;
-            }
-        }
-    }
-
-    gc_sweeping_exit(objspace);
-}
-
-VALUE
-rb_gc_impl_location(void *objspace_ptr, VALUE value)
-{
-    VALUE destination;
-
-    if (!SPECIAL_CONST_P(value)) {
-        asan_unpoisoning_object(value) {
-            if (BUILTIN_TYPE(value) == T_MOVED) {
-                destination = (VALUE)RMOVED(value)->destination;
-                GC_ASSERT(BUILTIN_TYPE(destination) != T_NONE);
-            }
-            else {
-                destination = value;
-            }
-        }
-    }
-    else {
-        destination = value;
-    }
-
-    return destination;
-}
-
-#if GC_CAN_COMPILE_COMPACTION
-static void
-invalidate_moved_plane(rb_objspace_t *objspace, struct heap_page *page, uintptr_t p, bits_t bitset)
-{
-    if (bitset) {
-        do {
-            if (bitset & 1) {
-                VALUE forwarding_object = (VALUE)p;
-                VALUE object;
-
-                if (BUILTIN_TYPE(forwarding_object) == T_MOVED) {
-                    GC_ASSERT(RVALUE_PINNED(objspace, forwarding_object));
-                    GC_ASSERT(!RVALUE_MARKED(objspace, forwarding_object));
-
-                    CLEAR_IN_BITMAP(GET_HEAP_PINNED_BITS(forwarding_object), forwarding_object);
-
-                    object = rb_gc_impl_location(objspace, forwarding_object);
-
-                    uint32_t original_shape_id = 0;
-                    if (RB_TYPE_P(object, T_OBJECT)) {
-                        original_shape_id = RMOVED(forwarding_object)->original_shape_id;
-                    }
-
-                    gc_move(objspace, object, forwarding_object, GET_HEAP_PAGE(object)->slot_size, page->slot_size);
-                    /* forwarding_object is now our actual object, and "object"
-                     * is the free slot for the original page */
-
-                    if (original_shape_id) {
-                        rb_gc_set_shape(forwarding_object, original_shape_id);
-                    }
-
-                    struct heap_page *orig_page = GET_HEAP_PAGE(object);
-                    orig_page->free_slots++;
-                    heap_page_add_freeobj(objspace, orig_page, object);
-
-                    GC_ASSERT(RVALUE_MARKED(objspace, forwarding_object));
-                    GC_ASSERT(BUILTIN_TYPE(forwarding_object) != T_MOVED);
-                    GC_ASSERT(BUILTIN_TYPE(forwarding_object) != T_NONE);
-                }
-            }
-            p += BASE_SLOT_SIZE;
-            bitset >>= 1;
-        } while (bitset);
-    }
-}
-
-static void
-invalidate_moved_page(rb_objspace_t *objspace, struct heap_page *page)
-{
-    int i;
-    bits_t *mark_bits, *pin_bits;
-    bits_t bitset;
-
-    mark_bits = page->mark_bits;
-    pin_bits = page->pinned_bits;
-
-    uintptr_t p = page->start;
-
-    // Skip out of range slots at the head of the page
-    bitset = pin_bits[0] & ~mark_bits[0];
-    bitset >>= NUM_IN_PAGE(p);
-    invalidate_moved_plane(objspace, page, p, bitset);
-    p += (BITS_BITLENGTH - NUM_IN_PAGE(p)) * BASE_SLOT_SIZE;
-
-    for (i=1; i < HEAP_PAGE_BITMAP_LIMIT; i++) {
-        /* Moved objects are pinned but never marked. We reuse the pin bits
-         * to indicate there is a moved object in this slot. */
-        bitset = pin_bits[i] & ~mark_bits[i];
-
-        invalidate_moved_plane(objspace, page, p, bitset);
-        p += BITS_BITLENGTH * BASE_SLOT_SIZE;
-    }
-}
-#endif
-
-static void
-gc_compact_start(rb_objspace_t *objspace)
-{
-    struct heap_page *page = NULL;
-    gc_mode_transition(objspace, gc_mode_compacting);
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        ccan_list_for_each(&heap->pages, page, page_node) {
-            page->flags.before_sweep = TRUE;
-        }
-
-        heap->compact_cursor = ccan_list_tail(&heap->pages, struct heap_page, page_node);
-        heap->compact_cursor_index = 0;
-    }
-
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->moved_objects = objspace->rcompactor.total_moved;
-    }
-
-    memset(objspace->rcompactor.considered_count_table, 0, T_MASK * sizeof(size_t));
-    memset(objspace->rcompactor.moved_count_table, 0, T_MASK * sizeof(size_t));
-    memset(objspace->rcompactor.moved_up_count_table, 0, T_MASK * sizeof(size_t));
-    memset(objspace->rcompactor.moved_down_count_table, 0, T_MASK * sizeof(size_t));
-
-    /* Set up read barrier for pages containing MOVED objects */
-    install_handlers();
-}
-
-static void gc_sweep_compact(rb_objspace_t *objspace);
-
-static void
-gc_sweep(rb_objspace_t *objspace)
-{
-    gc_sweeping_enter(objspace);
-
-    const unsigned int immediate_sweep = objspace->flags.immediate_sweep;
-
-    gc_report(1, objspace, "gc_sweep: immediate: %d\n", immediate_sweep);
-
-    gc_sweep_start(objspace);
-    if (objspace->flags.during_compacting) {
-        gc_sweep_compact(objspace);
-    }
-
-    if (immediate_sweep) {
-#if !GC_ENABLE_LAZY_SWEEP
-        gc_prof_sweep_timer_start(objspace);
-#endif
-        gc_sweep_rest(objspace);
-#if !GC_ENABLE_LAZY_SWEEP
-        gc_prof_sweep_timer_stop(objspace);
-#endif
-    }
-    else {
-
-        /* Sweep every size pool. */
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rb_heap_t *heap = &heaps[i];
-            gc_sweep_step(objspace, heap);
-        }
-    }
-
-    gc_sweeping_exit(objspace);
-}
-
-/* Marking - Marking stack */
-
-static stack_chunk_t *
-stack_chunk_alloc(void)
-{
-    stack_chunk_t *res;
-
-    res = malloc(sizeof(stack_chunk_t));
-    if (!res)
-        rb_memerror();
-
-    return res;
-}
-
-static inline int
-is_mark_stack_empty(mark_stack_t *stack)
-{
-    return stack->chunk == NULL;
-}
-
-static size_t
-mark_stack_size(mark_stack_t *stack)
-{
-    size_t size = stack->index;
-    stack_chunk_t *chunk = stack->chunk ? stack->chunk->next : NULL;
-
-    while (chunk) {
-        size += stack->limit;
-        chunk = chunk->next;
-    }
-    return size;
-}
-
-static void
-add_stack_chunk_cache(mark_stack_t *stack, stack_chunk_t *chunk)
-{
-    chunk->next = stack->cache;
-    stack->cache = chunk;
-    stack->cache_size++;
-}
-
-static void
-shrink_stack_chunk_cache(mark_stack_t *stack)
-{
-    stack_chunk_t *chunk;
-
-    if (stack->unused_cache_size > (stack->cache_size/2)) {
-        chunk = stack->cache;
-        stack->cache = stack->cache->next;
-        stack->cache_size--;
-        free(chunk);
-    }
-    stack->unused_cache_size = stack->cache_size;
-}
-
-static void
-push_mark_stack_chunk(mark_stack_t *stack)
-{
-    stack_chunk_t *next;
-
-    GC_ASSERT(stack->index == stack->limit);
-
-    if (stack->cache_size > 0) {
-        next = stack->cache;
-        stack->cache = stack->cache->next;
-        stack->cache_size--;
-        if (stack->unused_cache_size > stack->cache_size)
-            stack->unused_cache_size = stack->cache_size;
-    }
-    else {
-        next = stack_chunk_alloc();
-    }
-    next->next = stack->chunk;
-    stack->chunk = next;
-    stack->index = 0;
-}
-
-static void
-pop_mark_stack_chunk(mark_stack_t *stack)
-{
-    stack_chunk_t *prev;
-
-    prev = stack->chunk->next;
-    GC_ASSERT(stack->index == 0);
-    add_stack_chunk_cache(stack, stack->chunk);
-    stack->chunk = prev;
-    stack->index = stack->limit;
-}
-
-static void
-mark_stack_chunk_list_free(stack_chunk_t *chunk)
-{
-    stack_chunk_t *next = NULL;
-
-    while (chunk != NULL) {
-        next = chunk->next;
-        free(chunk);
-        chunk = next;
-    }
-}
-
-static void
-free_stack_chunks(mark_stack_t *stack)
-{
-    mark_stack_chunk_list_free(stack->chunk);
-}
-
-static void
-mark_stack_free_cache(mark_stack_t *stack)
-{
-    mark_stack_chunk_list_free(stack->cache);
-    stack->cache_size = 0;
-    stack->unused_cache_size = 0;
-}
-
-static void
-push_mark_stack(mark_stack_t *stack, VALUE obj)
-{
-    switch (BUILTIN_TYPE(obj)) {
-      case T_OBJECT:
-      case T_CLASS:
-      case T_MODULE:
-      case T_FLOAT:
-      case T_STRING:
-      case T_REGEXP:
-      case T_ARRAY:
-      case T_HASH:
-      case T_STRUCT:
-      case T_BIGNUM:
-      case T_FILE:
-      case T_DATA:
-      case T_MATCH:
-      case T_COMPLEX:
-      case T_RATIONAL:
-      case T_TRUE:
-      case T_FALSE:
-      case T_SYMBOL:
-      case T_IMEMO:
-      case T_ICLASS:
-        if (stack->index == stack->limit) {
-            push_mark_stack_chunk(stack);
-        }
-        stack->chunk->data[stack->index++] = obj;
-        return;
-
-      case T_NONE:
-      case T_NIL:
-      case T_FIXNUM:
-      case T_MOVED:
-      case T_ZOMBIE:
-      case T_UNDEF:
-      case T_MASK:
-        rb_bug("push_mark_stack() called for broken object");
-        break;
-
-      case T_NODE:
-        rb_bug("push_mark_stack: unexpected T_NODE object");
-        break;
-    }
-
-    rb_bug("rb_gc_mark(): unknown data type 0x%x(%p) %s",
-            BUILTIN_TYPE(obj), (void *)obj,
-            is_pointer_to_heap((rb_objspace_t *)rb_gc_get_objspace(), (void *)obj) ? "corrupted object" : "non object");
-}
-
-static int
-pop_mark_stack(mark_stack_t *stack, VALUE *data)
-{
-    if (is_mark_stack_empty(stack)) {
-        return FALSE;
-    }
-    if (stack->index == 1) {
-        *data = stack->chunk->data[--stack->index];
-        pop_mark_stack_chunk(stack);
-    }
-    else {
-        *data = stack->chunk->data[--stack->index];
-    }
-    return TRUE;
-}
-
-static void
-init_mark_stack(mark_stack_t *stack)
-{
-    int i;
-
-    MEMZERO(stack, mark_stack_t, 1);
-    stack->index = stack->limit = STACK_CHUNK_SIZE;
-
-    for (i=0; i < 4; i++) {
-        add_stack_chunk_cache(stack, stack_chunk_alloc());
-    }
-    stack->unused_cache_size = stack->cache_size;
-}
-
-/* Marking */
-
-static void
-rgengc_check_relation(rb_objspace_t *objspace, VALUE obj)
-{
-    const VALUE old_parent = objspace->rgengc.parent_object;
-
-    if (old_parent) { /* parent object is old */
-        if (RVALUE_WB_UNPROTECTED(objspace, obj) || !RVALUE_OLD_P(objspace, obj)) {
-            rgengc_remember(objspace, old_parent);
-        }
-    }
-
-    GC_ASSERT(old_parent == objspace->rgengc.parent_object);
-}
-
-static inline int
-gc_mark_set(rb_objspace_t *objspace, VALUE obj)
-{
-    if (RVALUE_MARKED(objspace, obj)) return 0;
-    MARK_IN_BITMAP(GET_HEAP_MARK_BITS(obj), obj);
-    return 1;
-}
-
-static void
-gc_aging(rb_objspace_t *objspace, VALUE obj)
-{
-    /* Disable aging if Major GC's are disabled. This will prevent longish lived
-     * objects filling up the heap at the expense of marking many more objects.
-     *
-     * We should always pre-warm our process when disabling majors, by running
-     * GC manually several times so that most objects likely to become oldgen
-     * are already oldgen.
-     */
-    if(!gc_config_full_mark_val)
-        return;
-
-    struct heap_page *page = GET_HEAP_PAGE(obj);
-
-    GC_ASSERT(RVALUE_MARKING(objspace, obj) == FALSE);
-    check_rvalue_consistency(objspace, obj);
-
-    if (!RVALUE_PAGE_WB_UNPROTECTED(page, obj)) {
-        if (!RVALUE_OLD_P(objspace, obj)) {
-            gc_report(3, objspace, "gc_aging: YOUNG: %s\n", rb_obj_info(obj));
-            RVALUE_AGE_INC(objspace, obj);
-        }
-        else if (is_full_marking(objspace)) {
-            GC_ASSERT(RVALUE_PAGE_UNCOLLECTIBLE(page, obj) == FALSE);
-            RVALUE_PAGE_OLD_UNCOLLECTIBLE_SET(objspace, page, obj);
-        }
-    }
-    check_rvalue_consistency(objspace, obj);
-
-    objspace->marked_slots++;
-}
-
-static void
-gc_grey(rb_objspace_t *objspace, VALUE obj)
-{
-#if RGENGC_CHECK_MODE
-    if (RVALUE_MARKED(objspace, obj) == FALSE) rb_bug("gc_grey: %s is not marked.", rb_obj_info(obj));
-    if (RVALUE_MARKING(objspace, obj) == TRUE) rb_bug("gc_grey: %s is marking/remembered.", rb_obj_info(obj));
-#endif
-
-    if (is_incremental_marking(objspace)) {
-        MARK_IN_BITMAP(GET_HEAP_MARKING_BITS(obj), obj);
-    }
-
-    push_mark_stack(&objspace->mark_stack, obj);
-}
-
-static void
-gc_mark(rb_objspace_t *objspace, VALUE obj)
-{
-    GC_ASSERT(during_gc);
-
-    rgengc_check_relation(objspace, obj);
-    if (!gc_mark_set(objspace, obj)) return; /* already marked */
-
-    if (0) { // for debug GC marking miss
-        if (objspace->rgengc.parent_object) {
-            RUBY_DEBUG_LOG("%p (%s) parent:%p (%s)",
-                            (void *)obj, obj_type_name(obj),
-                            (void *)objspace->rgengc.parent_object, obj_type_name(objspace->rgengc.parent_object));
-        }
-        else {
-            RUBY_DEBUG_LOG("%p (%s)", (void *)obj, obj_type_name(obj));
-        }
-    }
-
-    if (RB_UNLIKELY(RB_TYPE_P(obj, T_NONE))) {
-        rb_obj_info_dump(obj);
-        rb_bug("try to mark T_NONE object"); /* check here will help debugging */
-    }
-
-    gc_aging(objspace, obj);
-    gc_grey(objspace, obj);
-}
-
-static inline void
-gc_pin(rb_objspace_t *objspace, VALUE obj)
-{
-    GC_ASSERT(!SPECIAL_CONST_P(obj));
-    if (RB_UNLIKELY(objspace->flags.during_compacting)) {
-        if (RB_LIKELY(during_gc)) {
-            if (!RVALUE_PINNED(objspace, obj)) {
-                GC_ASSERT(GET_HEAP_PAGE(obj)->pinned_slots <= GET_HEAP_PAGE(obj)->total_slots);
-                GET_HEAP_PAGE(obj)->pinned_slots++;
-                MARK_IN_BITMAP(GET_HEAP_PINNED_BITS(obj), obj);
-            }
-        }
-    }
-}
-
-static inline void
-gc_mark_and_pin(rb_objspace_t *objspace, VALUE obj)
-{
-    gc_pin(objspace, obj);
-    gc_mark(objspace, obj);
-}
-
-void
-rb_gc_impl_mark_and_move(void *objspace_ptr, VALUE *ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (RB_UNLIKELY(objspace->flags.during_reference_updating)) {
-        GC_ASSERT(objspace->flags.during_compacting);
-        GC_ASSERT(during_gc);
-
-        *ptr = rb_gc_impl_location(objspace, *ptr);
-    }
-    else {
-        gc_mark(objspace, *ptr);
-    }
-}
-
-void
-rb_gc_impl_mark(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    gc_mark(objspace, obj);
-}
-
-void
-rb_gc_impl_mark_and_pin(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    gc_mark_and_pin(objspace, obj);
-}
-
-void
-rb_gc_impl_mark_maybe(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    (void)VALGRIND_MAKE_MEM_DEFINED(&obj, sizeof(obj));
-
-    if (is_pointer_to_heap(objspace, (void *)obj)) {
-        asan_unpoisoning_object(obj) {
-            /* Garbage can live on the stack, so do not mark or pin */
-            switch (BUILTIN_TYPE(obj)) {
-            case T_ZOMBIE:
-            case T_NONE:
-                break;
-            default:
-                gc_mark_and_pin(objspace, obj);
-                break;
-            }
-        }
-    }
-}
-
-void
-rb_gc_impl_mark_weak(void *objspace_ptr, VALUE *ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    GC_ASSERT(objspace->rgengc.parent_object == 0 || FL_TEST(objspace->rgengc.parent_object, FL_WB_PROTECTED));
-
-    VALUE obj = *ptr;
-
-    if (RB_UNLIKELY(RB_TYPE_P(obj, T_NONE))) {
-        rb_obj_info_dump(obj);
-        rb_bug("try to mark T_NONE object");
-    }
-
-    /* If we are in a minor GC and the other object is old, then obj should
-     * already be marked and cannot be reclaimed in this GC cycle so we don't
-     * need to add it to the weak references list. */
-    if (!is_full_marking(objspace) && RVALUE_OLD_P(objspace, obj)) {
-        GC_ASSERT(RVALUE_MARKED(objspace, obj));
-        GC_ASSERT(!objspace->flags.during_compacting);
-
-        return;
-    }
-
-    rgengc_check_relation(objspace, obj);
-
-    DURING_GC_COULD_MALLOC_REGION_START();
-    {
-        rb_darray_append(&objspace->weak_references, ptr);
-    }
-    DURING_GC_COULD_MALLOC_REGION_END();
-
-    objspace->profile.weak_references_count++;
-}
-
-void
-rb_gc_impl_remove_weak(void *objspace_ptr, VALUE parent_obj, VALUE *ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    /* If we're not incremental marking, then the state of the objects can't
-     * change so we don't need to do anything. */
-    if (!is_incremental_marking(objspace)) return;
-    /* If parent_obj has not been marked, then ptr has not yet been marked
-     * weak, so we don't need to do anything. */
-    if (!RVALUE_MARKED(objspace, parent_obj)) return;
-
-    VALUE **ptr_ptr;
-    rb_darray_foreach(objspace->weak_references, i, ptr_ptr) {
-        if (*ptr_ptr == ptr) {
-            *ptr_ptr = NULL;
-            break;
-        }
-    }
-}
-
-static int
-pin_value(st_data_t key, st_data_t value, st_data_t data)
-{
-    rb_gc_impl_mark_and_pin((void *)data, (VALUE)value);
-
-    return ST_CONTINUE;
-}
-
-static void
-mark_roots(rb_objspace_t *objspace, const char **categoryp)
-{
-#define MARK_CHECKPOINT(category) do { \
-    if (categoryp) *categoryp = category; \
-} while (0)
-
-    MARK_CHECKPOINT("objspace");
-    objspace->rgengc.parent_object = Qfalse;
-
-    if (finalizer_table != NULL) {
-        st_foreach(finalizer_table, pin_value, (st_data_t)objspace);
-    }
-
-    st_foreach(objspace->obj_to_id_tbl, gc_mark_tbl_no_pin_i, (st_data_t)objspace);
-
-    if (stress_to_class) rb_gc_mark(stress_to_class);
-
-    rb_gc_mark_roots(objspace, categoryp);
-}
-
-static inline void
-gc_mark_set_parent(rb_objspace_t *objspace, VALUE obj)
-{
-    if (RVALUE_OLD_P(objspace, obj)) {
-        objspace->rgengc.parent_object = obj;
-    }
-    else {
-        objspace->rgengc.parent_object = Qfalse;
-    }
-}
-
-static void
-gc_mark_children(rb_objspace_t *objspace, VALUE obj)
-{
-    gc_mark_set_parent(objspace, obj);
-    rb_gc_mark_children(objspace, obj);
-}
-
-/**
- * incremental: 0 -> not incremental (do all)
- * incremental: n -> mark at most `n' objects
- */
-static inline int
-gc_mark_stacked_objects(rb_objspace_t *objspace, int incremental, size_t count)
-{
-    mark_stack_t *mstack = &objspace->mark_stack;
-    VALUE obj;
-    size_t marked_slots_at_the_beginning = objspace->marked_slots;
-    size_t popped_count = 0;
-
-    while (pop_mark_stack(mstack, &obj)) {
-        if (obj == Qundef) continue; /* skip */
-
-        if (RGENGC_CHECK_MODE && !RVALUE_MARKED(objspace, obj)) {
-            rb_bug("gc_mark_stacked_objects: %s is not marked.", rb_obj_info(obj));
-        }
-        gc_mark_children(objspace, obj);
-
-        if (incremental) {
-            if (RGENGC_CHECK_MODE && !RVALUE_MARKING(objspace, obj)) {
-                rb_bug("gc_mark_stacked_objects: incremental, but marking bit is 0");
-            }
-            CLEAR_IN_BITMAP(GET_HEAP_MARKING_BITS(obj), obj);
-            popped_count++;
-
-            if (popped_count + (objspace->marked_slots - marked_slots_at_the_beginning) > count) {
-                break;
-            }
-        }
-        else {
-            /* just ignore marking bits */
-        }
-    }
-
-    if (RGENGC_CHECK_MODE >= 3) gc_verify_internal_consistency(objspace);
-
-    if (is_mark_stack_empty(mstack)) {
-        shrink_stack_chunk_cache(mstack);
-        return TRUE;
-    }
-    else {
-        return FALSE;
-    }
-}
-
-static int
-gc_mark_stacked_objects_incremental(rb_objspace_t *objspace, size_t count)
-{
-    return gc_mark_stacked_objects(objspace, TRUE, count);
-}
-
-static int
-gc_mark_stacked_objects_all(rb_objspace_t *objspace)
-{
-    return gc_mark_stacked_objects(objspace, FALSE, 0);
-}
-
-#if RGENGC_CHECK_MODE >= 4
-
-#define MAKE_ROOTSIG(obj) (((VALUE)(obj) << 1) | 0x01)
-#define IS_ROOTSIG(obj)   ((VALUE)(obj) & 0x01)
-#define GET_ROOTSIG(obj)  ((const char *)((VALUE)(obj) >> 1))
-
-struct reflist {
-    VALUE *list;
-    int pos;
-    int size;
-};
-
-static struct reflist *
-reflist_create(VALUE obj)
-{
-    struct reflist *refs = xmalloc(sizeof(struct reflist));
-    refs->size = 1;
-    refs->list = ALLOC_N(VALUE, refs->size);
-    refs->list[0] = obj;
-    refs->pos = 1;
-    return refs;
-}
-
-static void
-reflist_destruct(struct reflist *refs)
-{
-    xfree(refs->list);
-    xfree(refs);
-}
-
-static void
-reflist_add(struct reflist *refs, VALUE obj)
-{
-    if (refs->pos == refs->size) {
-        refs->size *= 2;
-        SIZED_REALLOC_N(refs->list, VALUE, refs->size, refs->size/2);
-    }
-
-    refs->list[refs->pos++] = obj;
-}
-
-static void
-reflist_dump(struct reflist *refs)
-{
-    int i;
-    for (i=0; i<refs->pos; i++) {
-        VALUE obj = refs->list[i];
-        if (IS_ROOTSIG(obj)) { /* root */
-            fprintf(stderr, "<root@%s>", GET_ROOTSIG(obj));
-        }
-        else {
-            fprintf(stderr, "<%s>", rb_obj_info(obj));
-        }
-        if (i+1 < refs->pos) fprintf(stderr, ", ");
-    }
-}
-
-static int
-reflist_referred_from_machine_context(struct reflist *refs)
-{
-    int i;
-    for (i=0; i<refs->pos; i++) {
-        VALUE obj = refs->list[i];
-        if (IS_ROOTSIG(obj) && strcmp(GET_ROOTSIG(obj), "machine_context") == 0) return 1;
-    }
-    return 0;
-}
-
-struct allrefs {
-    rb_objspace_t *objspace;
-    /* a -> obj1
-     * b -> obj1
-     * c -> obj1
-     * c -> obj2
-     * d -> obj3
-     * #=> {obj1 => [a, b, c], obj2 => [c, d]}
-     */
-    struct st_table *references;
-    const char *category;
-    VALUE root_obj;
-    mark_stack_t mark_stack;
-};
-
-static int
-allrefs_add(struct allrefs *data, VALUE obj)
-{
-    struct reflist *refs;
-    st_data_t r;
-
-    if (st_lookup(data->references, obj, &r)) {
-        refs = (struct reflist *)r;
-        reflist_add(refs, data->root_obj);
-        return 0;
-    }
-    else {
-        refs = reflist_create(data->root_obj);
-        st_insert(data->references, obj, (st_data_t)refs);
-        return 1;
-    }
-}
-
-static void
-allrefs_i(VALUE obj, void *ptr)
-{
-    struct allrefs *data = (struct allrefs *)ptr;
-
-    if (allrefs_add(data, obj)) {
-        push_mark_stack(&data->mark_stack, obj);
-    }
-}
-
-static void
-allrefs_roots_i(VALUE obj, void *ptr)
-{
-    struct allrefs *data = (struct allrefs *)ptr;
-    if (strlen(data->category) == 0) rb_bug("!!!");
-    data->root_obj = MAKE_ROOTSIG(data->category);
-
-    if (allrefs_add(data, obj)) {
-        push_mark_stack(&data->mark_stack, obj);
-    }
-}
-#define PUSH_MARK_FUNC_DATA(v) do { \
-    struct gc_mark_func_data_struct *prev_mark_func_data = GET_VM()->gc.mark_func_data; \
-    GET_VM()->gc.mark_func_data = (v);
-
-#define POP_MARK_FUNC_DATA() GET_VM()->gc.mark_func_data = prev_mark_func_data;} while (0)
-
-static st_table *
-objspace_allrefs(rb_objspace_t *objspace)
-{
-    struct allrefs data;
-    struct gc_mark_func_data_struct mfd;
-    VALUE obj;
-    int prev_dont_gc = dont_gc_val();
-    dont_gc_on();
-
-    data.objspace = objspace;
-    data.references = st_init_numtable();
-    init_mark_stack(&data.mark_stack);
-
-    mfd.mark_func = allrefs_roots_i;
-    mfd.data = &data;
-
-    /* traverse root objects */
-    PUSH_MARK_FUNC_DATA(&mfd);
-    GET_VM()->gc.mark_func_data = &mfd;
-    mark_roots(objspace, &data.category);
-    POP_MARK_FUNC_DATA();
-
-    /* traverse rest objects reachable from root objects */
-    while (pop_mark_stack(&data.mark_stack, &obj)) {
-        rb_objspace_reachable_objects_from(data.root_obj = obj, allrefs_i, &data);
-    }
-    free_stack_chunks(&data.mark_stack);
-
-    dont_gc_set(prev_dont_gc);
-    return data.references;
-}
-
-static int
-objspace_allrefs_destruct_i(st_data_t key, st_data_t value, st_data_t ptr)
-{
-    struct reflist *refs = (struct reflist *)value;
-    reflist_destruct(refs);
-    return ST_CONTINUE;
-}
-
-static void
-objspace_allrefs_destruct(struct st_table *refs)
-{
-    st_foreach(refs, objspace_allrefs_destruct_i, 0);
-    st_free_table(refs);
-}
-
-#if RGENGC_CHECK_MODE >= 5
-static int
-allrefs_dump_i(st_data_t k, st_data_t v, st_data_t ptr)
-{
-    VALUE obj = (VALUE)k;
-    struct reflist *refs = (struct reflist *)v;
-    fprintf(stderr, "[allrefs_dump_i] %s <- ", rb_obj_info(obj));
-    reflist_dump(refs);
-    fprintf(stderr, "\n");
-    return ST_CONTINUE;
-}
-
-static void
-allrefs_dump(rb_objspace_t *objspace)
-{
-    VALUE size = objspace->rgengc.allrefs_table->num_entries;
-    fprintf(stderr, "[all refs] (size: %"PRIuVALUE")\n", size);
-    st_foreach(objspace->rgengc.allrefs_table, allrefs_dump_i, 0);
-}
-#endif
-
-static int
-gc_check_after_marks_i(st_data_t k, st_data_t v, st_data_t ptr)
-{
-    VALUE obj = k;
-    struct reflist *refs = (struct reflist *)v;
-    rb_objspace_t *objspace = (rb_objspace_t *)ptr;
-
-    /* object should be marked or oldgen */
-    if (!RVALUE_MARKED(objspace, obj)) {
-        fprintf(stderr, "gc_check_after_marks_i: %s is not marked and not oldgen.\n", rb_obj_info(obj));
-        fprintf(stderr, "gc_check_after_marks_i: %p is referred from ", (void *)obj);
-        reflist_dump(refs);
-
-        if (reflist_referred_from_machine_context(refs)) {
-            fprintf(stderr, " (marked from machine stack).\n");
-            /* marked from machine context can be false positive */
-        }
-        else {
-            objspace->rgengc.error_count++;
-            fprintf(stderr, "\n");
-        }
-    }
-    return ST_CONTINUE;
-}
-
-static void
-gc_marks_check(rb_objspace_t *objspace, st_foreach_callback_func *checker_func, const char *checker_name)
-{
-    size_t saved_malloc_increase = objspace->malloc_params.increase;
-#if RGENGC_ESTIMATE_OLDMALLOC
-    size_t saved_oldmalloc_increase = objspace->rgengc.oldmalloc_increase;
-#endif
-    VALUE already_disabled = rb_objspace_gc_disable(objspace);
-
-    objspace->rgengc.allrefs_table = objspace_allrefs(objspace);
-
-    if (checker_func) {
-        st_foreach(objspace->rgengc.allrefs_table, checker_func, (st_data_t)objspace);
-    }
-
-    if (objspace->rgengc.error_count > 0) {
-#if RGENGC_CHECK_MODE >= 5
-        allrefs_dump(objspace);
-#endif
-        if (checker_name) rb_bug("%s: GC has problem.", checker_name);
-    }
-
-    objspace_allrefs_destruct(objspace->rgengc.allrefs_table);
-    objspace->rgengc.allrefs_table = 0;
-
-    if (already_disabled == Qfalse) rb_objspace_gc_enable(objspace);
-    objspace->malloc_params.increase = saved_malloc_increase;
-#if RGENGC_ESTIMATE_OLDMALLOC
-    objspace->rgengc.oldmalloc_increase = saved_oldmalloc_increase;
-#endif
-}
-#endif /* RGENGC_CHECK_MODE >= 4 */
-
-struct verify_internal_consistency_struct {
-    rb_objspace_t *objspace;
-    int err_count;
-    size_t live_object_count;
-    size_t zombie_object_count;
-
-    VALUE parent;
-    size_t old_object_count;
-    size_t remembered_shady_count;
-};
-
-static void
-check_generation_i(const VALUE child, void *ptr)
-{
-    struct verify_internal_consistency_struct *data = (struct verify_internal_consistency_struct *)ptr;
-    const VALUE parent = data->parent;
-
-    if (RGENGC_CHECK_MODE) GC_ASSERT(RVALUE_OLD_P(data->objspace, parent));
-
-    if (!RVALUE_OLD_P(data->objspace, child)) {
-        if (!RVALUE_REMEMBERED(data->objspace, parent) &&
-            !RVALUE_REMEMBERED(data->objspace, child) &&
-            !RVALUE_UNCOLLECTIBLE(data->objspace, child)) {
-            fprintf(stderr, "verify_internal_consistency_reachable_i: WB miss (O->Y) %s -> %s\n", rb_obj_info(parent), rb_obj_info(child));
-            data->err_count++;
-        }
-    }
-}
-
-static void
-check_color_i(const VALUE child, void *ptr)
-{
-    struct verify_internal_consistency_struct *data = (struct verify_internal_consistency_struct *)ptr;
-    const VALUE parent = data->parent;
-
-    if (!RVALUE_WB_UNPROTECTED(data->objspace, parent) && RVALUE_WHITE_P(data->objspace, child)) {
-        fprintf(stderr, "verify_internal_consistency_reachable_i: WB miss (B->W) - %s -> %s\n",
-                rb_obj_info(parent), rb_obj_info(child));
-        data->err_count++;
-    }
-}
-
-static void
-check_children_i(const VALUE child, void *ptr)
-{
-    struct verify_internal_consistency_struct *data = (struct verify_internal_consistency_struct *)ptr;
-    if (check_rvalue_consistency_force(data->objspace, child, FALSE) != 0) {
-        fprintf(stderr, "check_children_i: %s has error (referenced from %s)",
-                rb_obj_info(child), rb_obj_info(data->parent));
-
-        data->err_count++;
-    }
-}
-
-static int
-verify_internal_consistency_i(void *page_start, void *page_end, size_t stride,
-                              struct verify_internal_consistency_struct *data)
-{
-    VALUE obj;
-    rb_objspace_t *objspace = data->objspace;
-
-    for (obj = (VALUE)page_start; obj != (VALUE)page_end; obj += stride) {
-        asan_unpoisoning_object(obj) {
-            if (!rb_gc_impl_garbage_object_p(objspace, obj)) {
-                /* count objects */
-                data->live_object_count++;
-                data->parent = obj;
-
-                /* Normally, we don't expect T_MOVED objects to be in the heap.
-                * But they can stay alive on the stack, */
-                if (!gc_object_moved_p(objspace, obj)) {
-                    /* moved slots don't have children */
-                    rb_objspace_reachable_objects_from(obj, check_children_i, (void *)data);
-                }
-
-                /* check health of children */
-                if (RVALUE_OLD_P(objspace, obj)) data->old_object_count++;
-                if (RVALUE_WB_UNPROTECTED(objspace, obj) && RVALUE_UNCOLLECTIBLE(objspace, obj)) data->remembered_shady_count++;
-
-                if (!is_marking(objspace) && RVALUE_OLD_P(objspace, obj)) {
-                    /* reachable objects from an oldgen object should be old or (young with remember) */
-                    data->parent = obj;
-                    rb_objspace_reachable_objects_from(obj, check_generation_i, (void *)data);
-                }
-
-                if (is_incremental_marking(objspace)) {
-                    if (RVALUE_BLACK_P(objspace, obj)) {
-                        /* reachable objects from black objects should be black or grey objects */
-                        data->parent = obj;
-                        rb_objspace_reachable_objects_from(obj, check_color_i, (void *)data);
-                    }
-                }
-            }
-            else {
-                if (BUILTIN_TYPE(obj) == T_ZOMBIE) {
-                    data->zombie_object_count++;
-
-                    if ((RBASIC(obj)->flags & ~ZOMBIE_OBJ_KEPT_FLAGS) != T_ZOMBIE) {
-                        fprintf(stderr, "verify_internal_consistency_i: T_ZOMBIE has extra flags set: %s\n",
-                                rb_obj_info(obj));
-                        data->err_count++;
-                    }
-
-                    if (!!FL_TEST(obj, FL_FINALIZE) != !!st_is_member(finalizer_table, obj)) {
-                        fprintf(stderr, "verify_internal_consistency_i: FL_FINALIZE %s but %s finalizer_table: %s\n",
-                                FL_TEST(obj, FL_FINALIZE) ? "set" : "not set", st_is_member(finalizer_table, obj) ? "in" : "not in",
-                                rb_obj_info(obj));
-                        data->err_count++;
-                    }
-                }
-            }
-        }
-    }
-
-    return 0;
-}
-
-static int
-gc_verify_heap_page(rb_objspace_t *objspace, struct heap_page *page, VALUE obj)
-{
-    unsigned int has_remembered_shady = FALSE;
-    unsigned int has_remembered_old = FALSE;
-    int remembered_old_objects = 0;
-    int free_objects = 0;
-    int zombie_objects = 0;
-
-    short slot_size = page->slot_size;
-    uintptr_t start = (uintptr_t)page->start;
-    uintptr_t end = start + page->total_slots * slot_size;
-
-    for (uintptr_t ptr = start; ptr < end; ptr += slot_size) {
-        VALUE val = (VALUE)ptr;
-        asan_unpoisoning_object(val) {
-            enum ruby_value_type type = BUILTIN_TYPE(val);
-
-            if (type == T_NONE) free_objects++;
-            if (type == T_ZOMBIE) zombie_objects++;
-            if (RVALUE_PAGE_UNCOLLECTIBLE(page, val) && RVALUE_PAGE_WB_UNPROTECTED(page, val)) {
-                has_remembered_shady = TRUE;
-            }
-            if (RVALUE_PAGE_MARKING(page, val)) {
-                has_remembered_old = TRUE;
-                remembered_old_objects++;
-            }
-        }
-    }
-
-    if (!is_incremental_marking(objspace) &&
-        page->flags.has_remembered_objects == FALSE && has_remembered_old == TRUE) {
-
-        for (uintptr_t ptr = start; ptr < end; ptr += slot_size) {
-            VALUE val = (VALUE)ptr;
-            if (RVALUE_PAGE_MARKING(page, val)) {
-                fprintf(stderr, "marking -> %s\n", rb_obj_info(val));
-            }
-        }
-        rb_bug("page %p's has_remembered_objects should be false, but there are remembered old objects (%d). %s",
-               (void *)page, remembered_old_objects, obj ? rb_obj_info(obj) : "");
-    }
-
-    if (page->flags.has_uncollectible_wb_unprotected_objects == FALSE && has_remembered_shady == TRUE) {
-        rb_bug("page %p's has_remembered_shady should be false, but there are remembered shady objects. %s",
-               (void *)page, obj ? rb_obj_info(obj) : "");
-    }
-
-    if (0) {
-        /* free_slots may not equal to free_objects */
-        if (page->free_slots != free_objects) {
-            rb_bug("page %p's free_slots should be %d, but %d", (void *)page, page->free_slots, free_objects);
-        }
-    }
-    if (page->final_slots != zombie_objects) {
-        rb_bug("page %p's final_slots should be %d, but %d", (void *)page, page->final_slots, zombie_objects);
-    }
-
-    return remembered_old_objects;
-}
-
-static int
-gc_verify_heap_pages_(rb_objspace_t *objspace, struct ccan_list_head *head)
-{
-    int remembered_old_objects = 0;
-    struct heap_page *page = 0;
-
-    ccan_list_for_each(head, page, page_node) {
-        asan_unlock_freelist(page);
-        struct free_slot *p = page->freelist;
-        while (p) {
-            VALUE vp = (VALUE)p;
-            VALUE prev = vp;
-            asan_unpoison_object(vp, false);
-            if (BUILTIN_TYPE(vp) != T_NONE) {
-                fprintf(stderr, "freelist slot expected to be T_NONE but was: %s\n", rb_obj_info(vp));
-            }
-            p = p->next;
-            asan_poison_object(prev);
-        }
-        asan_lock_freelist(page);
-
-        if (page->flags.has_remembered_objects == FALSE) {
-            remembered_old_objects += gc_verify_heap_page(objspace, page, Qfalse);
-        }
-    }
-
-    return remembered_old_objects;
-}
-
-static int
-gc_verify_heap_pages(rb_objspace_t *objspace)
-{
-    int remembered_old_objects = 0;
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        remembered_old_objects += gc_verify_heap_pages_(objspace, &((&heaps[i])->pages));
-    }
-    return remembered_old_objects;
-}
-
-static void
-gc_verify_internal_consistency_(rb_objspace_t *objspace)
-{
-    struct verify_internal_consistency_struct data = {0};
-
-    data.objspace = objspace;
-    gc_report(5, objspace, "gc_verify_internal_consistency: start\n");
-
-    /* check relations */
-    for (size_t i = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-        struct heap_page *page = rb_darray_get(objspace->heap_pages.sorted, i);
-        short slot_size = page->slot_size;
-
-        uintptr_t start = (uintptr_t)page->start;
-        uintptr_t end = start + page->total_slots * slot_size;
-
-        verify_internal_consistency_i((void *)start, (void *)end, slot_size, &data);
-    }
-
-    if (data.err_count != 0) {
-#if RGENGC_CHECK_MODE >= 5
-        objspace->rgengc.error_count = data.err_count;
-        gc_marks_check(objspace, NULL, NULL);
-        allrefs_dump(objspace);
-#endif
-        rb_bug("gc_verify_internal_consistency: found internal inconsistency.");
-    }
-
-    /* check heap_page status */
-    gc_verify_heap_pages(objspace);
-
-    /* check counters */
-
-    if (!is_lazy_sweeping(objspace) &&
-            !finalizing &&
-            !rb_gc_multi_ractor_p()) {
-        if (objspace_live_slots(objspace) != data.live_object_count) {
-            fprintf(stderr, "heap_pages_final_slots: %"PRIdSIZE", total_freed_objects: %"PRIdSIZE"\n",
-                    total_final_slots_count(objspace), total_freed_objects(objspace));
-            rb_bug("inconsistent live slot number: expect %"PRIuSIZE", but %"PRIuSIZE".",
-                   objspace_live_slots(objspace), data.live_object_count);
-        }
-    }
-
-    if (!is_marking(objspace)) {
-        if (objspace->rgengc.old_objects != data.old_object_count) {
-            rb_bug("inconsistent old slot number: expect %"PRIuSIZE", but %"PRIuSIZE".",
-                   objspace->rgengc.old_objects, data.old_object_count);
-        }
-        if (objspace->rgengc.uncollectible_wb_unprotected_objects != data.remembered_shady_count) {
-            rb_bug("inconsistent number of wb unprotected objects: expect %"PRIuSIZE", but %"PRIuSIZE".",
-                   objspace->rgengc.uncollectible_wb_unprotected_objects, data.remembered_shady_count);
-        }
-    }
-
-    if (!finalizing) {
-        size_t list_count = 0;
-
-        {
-            VALUE z = heap_pages_deferred_final;
-            while (z) {
-                list_count++;
-                z = RZOMBIE(z)->next;
-            }
-        }
-
-        if (total_final_slots_count(objspace) != data.zombie_object_count ||
-            total_final_slots_count(objspace) != list_count) {
-
-            rb_bug("inconsistent finalizing object count:\n"
-                    "  expect %"PRIuSIZE"\n"
-                    "  but    %"PRIuSIZE" zombies\n"
-                    "  heap_pages_deferred_final list has %"PRIuSIZE" items.",
-                    total_final_slots_count(objspace),
-                    data.zombie_object_count,
-                    list_count);
-        }
-    }
-
-    gc_report(5, objspace, "gc_verify_internal_consistency: OK\n");
-}
-
-static void
-gc_verify_internal_consistency(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    unsigned int lev = rb_gc_vm_lock();
-    {
-        rb_gc_vm_barrier(); // stop other ractors
-
-        unsigned int prev_during_gc = during_gc;
-        during_gc = FALSE; // stop gc here
-        {
-            gc_verify_internal_consistency_(objspace);
-        }
-        during_gc = prev_during_gc;
-    }
-    rb_gc_vm_unlock(lev);
-}
-
-static void
-heap_move_pooled_pages_to_free_pages(rb_heap_t *heap)
-{
-    if (heap->pooled_pages) {
-        if (heap->free_pages) {
-            struct heap_page *free_pages_tail = heap->free_pages;
-            while (free_pages_tail->free_next) {
-                free_pages_tail = free_pages_tail->free_next;
-            }
-            free_pages_tail->free_next = heap->pooled_pages;
-        }
-        else {
-            heap->free_pages = heap->pooled_pages;
-        }
-
-        heap->pooled_pages = NULL;
-    }
-}
-
-static int
-gc_remember_unprotected(rb_objspace_t *objspace, VALUE obj)
-{
-    struct heap_page *page = GET_HEAP_PAGE(obj);
-    bits_t *uncollectible_bits = &page->uncollectible_bits[0];
-
-    if (!MARKED_IN_BITMAP(uncollectible_bits, obj)) {
-        page->flags.has_uncollectible_wb_unprotected_objects = TRUE;
-        MARK_IN_BITMAP(uncollectible_bits, obj);
-        objspace->rgengc.uncollectible_wb_unprotected_objects++;
-
-#if RGENGC_PROFILE > 0
-        objspace->profile.total_remembered_shady_object_count++;
-#if RGENGC_PROFILE >= 2
-        objspace->profile.remembered_shady_object_count_types[BUILTIN_TYPE(obj)]++;
-#endif
-#endif
-        return TRUE;
-    }
-    else {
-        return FALSE;
-    }
-}
-
-static inline void
-gc_marks_wb_unprotected_objects_plane(rb_objspace_t *objspace, uintptr_t p, bits_t bits)
-{
-    if (bits) {
-        do {
-            if (bits & 1) {
-                gc_report(2, objspace, "gc_marks_wb_unprotected_objects: marked shady: %s\n", rb_obj_info((VALUE)p));
-                GC_ASSERT(RVALUE_WB_UNPROTECTED(objspace, (VALUE)p));
-                GC_ASSERT(RVALUE_MARKED(objspace, (VALUE)p));
-                gc_mark_children(objspace, (VALUE)p);
-            }
-            p += BASE_SLOT_SIZE;
-            bits >>= 1;
-        } while (bits);
-    }
-}
-
-static void
-gc_marks_wb_unprotected_objects(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    struct heap_page *page = 0;
-
-    ccan_list_for_each(&heap->pages, page, page_node) {
-        bits_t *mark_bits = page->mark_bits;
-        bits_t *wbun_bits = page->wb_unprotected_bits;
-        uintptr_t p = page->start;
-        size_t j;
-
-        bits_t bits = mark_bits[0] & wbun_bits[0];
-        bits >>= NUM_IN_PAGE(p);
-        gc_marks_wb_unprotected_objects_plane(objspace, p, bits);
-        p += (BITS_BITLENGTH - NUM_IN_PAGE(p)) * BASE_SLOT_SIZE;
-
-        for (j=1; j<HEAP_PAGE_BITMAP_LIMIT; j++) {
-            bits_t bits = mark_bits[j] & wbun_bits[j];
-
-            gc_marks_wb_unprotected_objects_plane(objspace, p, bits);
-            p += BITS_BITLENGTH * BASE_SLOT_SIZE;
-        }
-    }
-
-    gc_mark_stacked_objects_all(objspace);
-}
-
-static void
-gc_update_weak_references(rb_objspace_t *objspace)
-{
-    size_t retained_weak_references_count = 0;
-    VALUE **ptr_ptr;
-    rb_darray_foreach(objspace->weak_references, i, ptr_ptr) {
-        if (!*ptr_ptr) continue;
-
-        VALUE obj = **ptr_ptr;
-
-        if (RB_SPECIAL_CONST_P(obj)) continue;
-
-        if (!RVALUE_MARKED(objspace, obj)) {
-            **ptr_ptr = Qundef;
-        }
-        else {
-            retained_weak_references_count++;
-        }
-    }
-
-    objspace->profile.retained_weak_references_count = retained_weak_references_count;
-
-    rb_darray_clear(objspace->weak_references);
-    DURING_GC_COULD_MALLOC_REGION_START();
-    {
-        rb_darray_resize_capa(&objspace->weak_references, retained_weak_references_count);
-    }
-    DURING_GC_COULD_MALLOC_REGION_END();
-}
-
-static void
-gc_marks_finish(rb_objspace_t *objspace)
-{
-    /* finish incremental GC */
-    if (is_incremental_marking(objspace)) {
-        if (RGENGC_CHECK_MODE && is_mark_stack_empty(&objspace->mark_stack) == 0) {
-            rb_bug("gc_marks_finish: mark stack is not empty (%"PRIdSIZE").",
-                   mark_stack_size(&objspace->mark_stack));
-        }
-
-        mark_roots(objspace, NULL);
-        while (gc_mark_stacked_objects_incremental(objspace, INT_MAX) == false);
-
-#if RGENGC_CHECK_MODE >= 2
-        if (gc_verify_heap_pages(objspace) != 0) {
-            rb_bug("gc_marks_finish (incremental): there are remembered old objects.");
-        }
-#endif
-
-        objspace->flags.during_incremental_marking = FALSE;
-        /* check children of all marked wb-unprotected objects */
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            gc_marks_wb_unprotected_objects(objspace, &heaps[i]);
-        }
-    }
-
-    gc_update_weak_references(objspace);
-
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-
-#if RGENGC_CHECK_MODE >= 4
-    during_gc = FALSE;
-    gc_marks_check(objspace, gc_check_after_marks_i, "after_marks");
-    during_gc = TRUE;
-#endif
-
-    {
-        const unsigned long r_mul = objspace->live_ractor_cache_count > 8 ? 8 : objspace->live_ractor_cache_count; // upto 8
-
-        size_t total_slots = objspace_available_slots(objspace);
-        size_t sweep_slots = total_slots - objspace->marked_slots; /* will be swept slots */
-        size_t max_free_slots = (size_t)(total_slots * gc_params.heap_free_slots_max_ratio);
-        size_t min_free_slots = (size_t)(total_slots * gc_params.heap_free_slots_min_ratio);
-        if (min_free_slots < gc_params.heap_free_slots * r_mul) {
-            min_free_slots = gc_params.heap_free_slots * r_mul;
-        }
-
-        int full_marking = is_full_marking(objspace);
-
-        GC_ASSERT(objspace_available_slots(objspace) >= objspace->marked_slots);
-
-        /* Setup freeable slots. */
-        size_t total_init_slots = 0;
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            total_init_slots += gc_params.heap_init_slots[i] * r_mul;
-        }
-
-        if (max_free_slots < total_init_slots) {
-            max_free_slots = total_init_slots;
-        }
-
-        if (sweep_slots > max_free_slots) {
-            heap_pages_freeable_pages = (sweep_slots - max_free_slots) / HEAP_PAGE_OBJ_LIMIT;
-        }
-        else {
-            heap_pages_freeable_pages = 0;
-        }
-
-        if (objspace->heap_pages.allocatable_slots == 0 && sweep_slots < min_free_slots) {
-            if (!full_marking) {
-                if (objspace->profile.count - objspace->rgengc.last_major_gc < RVALUE_OLD_AGE) {
-                    full_marking = TRUE;
-                }
-                else {
-                    gc_report(1, objspace, "gc_marks_finish: next is full GC!!)\n");
-                    gc_needs_major_flags |= GPR_FLAG_MAJOR_BY_NOFREE;
-                }
-            }
-        }
-
-        if (full_marking) {
-            /* See the comment about RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR */
-            const double r = gc_params.oldobject_limit_factor;
-            objspace->rgengc.uncollectible_wb_unprotected_objects_limit = MAX(
-                (size_t)(objspace->rgengc.uncollectible_wb_unprotected_objects * r),
-                (size_t)(objspace->rgengc.old_objects * gc_params.uncollectible_wb_unprotected_objects_limit_ratio)
-            );
-            objspace->rgengc.old_objects_limit = (size_t)(objspace->rgengc.old_objects * r);
-        }
-
-        if (objspace->rgengc.uncollectible_wb_unprotected_objects > objspace->rgengc.uncollectible_wb_unprotected_objects_limit) {
-            gc_needs_major_flags |= GPR_FLAG_MAJOR_BY_SHADY;
-        }
-        if (objspace->rgengc.old_objects > objspace->rgengc.old_objects_limit) {
-            gc_needs_major_flags |= GPR_FLAG_MAJOR_BY_OLDGEN;
-        }
-
-        gc_report(1, objspace, "gc_marks_finish (marks %"PRIdSIZE" objects, "
-                  "old %"PRIdSIZE" objects, total %"PRIdSIZE" slots, "
-                  "sweep %"PRIdSIZE" slots, allocatable %"PRIdSIZE" slots, next GC: %s)\n",
-                  objspace->marked_slots, objspace->rgengc.old_objects, objspace_available_slots(objspace), sweep_slots, objspace->heap_pages.allocatable_slots,
-                  gc_needs_major_flags ? "major" : "minor");
-    }
-
-    // TODO: refactor so we don't need to call this
-    rb_ractor_finish_marking();
-
-    rb_gc_event_hook(0, RUBY_INTERNAL_EVENT_GC_END_MARK);
-}
-
-static bool
-gc_compact_heap_cursors_met_p(rb_heap_t *heap)
-{
-    return heap->sweeping_page == heap->compact_cursor;
-}
-
-
-static rb_heap_t *
-gc_compact_destination_pool(rb_objspace_t *objspace, rb_heap_t *src_pool, VALUE obj)
-{
-    size_t obj_size = rb_gc_obj_optimal_size(obj);
-    if (obj_size == 0) {
-        return src_pool;
-    }
-
-    size_t idx = 0;
-    if (rb_gc_impl_size_allocatable_p(obj_size)) {
-        idx = heap_idx_for_size(obj_size);
-    }
-
-    return &heaps[idx];
-}
-
-static bool
-gc_compact_move(rb_objspace_t *objspace, rb_heap_t *heap, VALUE src)
-{
-    GC_ASSERT(BUILTIN_TYPE(src) != T_MOVED);
-    GC_ASSERT(gc_is_moveable_obj(objspace, src));
-
-    rb_heap_t *dest_pool = gc_compact_destination_pool(objspace, heap, src);
-    uint32_t orig_shape = 0;
-    uint32_t new_shape = 0;
-
-    if (gc_compact_heap_cursors_met_p(dest_pool)) {
-        return dest_pool != heap;
-    }
-
-    if (RB_TYPE_P(src, T_OBJECT)) {
-        orig_shape = rb_gc_get_shape(src);
-
-        if (dest_pool != heap) {
-            new_shape = rb_gc_rebuild_shape(src, dest_pool - heaps);
-
-            if (new_shape == 0) {
-                dest_pool = heap;
-            }
-        }
-    }
-
-    while (!try_move(objspace, dest_pool, dest_pool->free_pages, src)) {
-        struct gc_sweep_context ctx = {
-            .page = dest_pool->sweeping_page,
-            .final_slots = 0,
-            .freed_slots = 0,
-            .empty_slots = 0,
-        };
-
-        /* The page of src could be partially compacted, so it may contain
-         * T_MOVED. Sweeping a page may read objects on this page, so we
-         * need to lock the page. */
-        lock_page_body(objspace, GET_PAGE_BODY(src));
-        gc_sweep_page(objspace, dest_pool, &ctx);
-        unlock_page_body(objspace, GET_PAGE_BODY(src));
-
-        if (dest_pool->sweeping_page->free_slots > 0) {
-            heap_add_freepage(dest_pool, dest_pool->sweeping_page);
-        }
-
-        dest_pool->sweeping_page = ccan_list_next(&dest_pool->pages, dest_pool->sweeping_page, page_node);
-        if (gc_compact_heap_cursors_met_p(dest_pool)) {
-            return dest_pool != heap;
-        }
-    }
-
-    if (orig_shape != 0) {
-        if (new_shape != 0) {
-            VALUE dest = rb_gc_impl_location(objspace, src);
-            rb_gc_set_shape(dest, new_shape);
-        }
-        RMOVED(src)->original_shape_id = orig_shape;
-    }
-
-    return true;
-}
-
-static bool
-gc_compact_plane(rb_objspace_t *objspace, rb_heap_t *heap, uintptr_t p, bits_t bitset, struct heap_page *page)
-{
-    short slot_size = page->slot_size;
-    short slot_bits = slot_size / BASE_SLOT_SIZE;
-    GC_ASSERT(slot_bits > 0);
-
-    do {
-        VALUE vp = (VALUE)p;
-        GC_ASSERT(vp % BASE_SLOT_SIZE == 0);
-
-        if (bitset & 1) {
-            objspace->rcompactor.considered_count_table[BUILTIN_TYPE(vp)]++;
-
-            if (gc_is_moveable_obj(objspace, vp)) {
-                if (!gc_compact_move(objspace, heap, vp)) {
-                    //the cursors met. bubble up
-                    return false;
-                }
-            }
-        }
-        p += slot_size;
-        bitset >>= slot_bits;
-    } while (bitset);
-
-    return true;
-}
-
-// Iterate up all the objects in page, moving them to where they want to go
-static bool
-gc_compact_page(rb_objspace_t *objspace, rb_heap_t *heap, struct heap_page *page)
-{
-    GC_ASSERT(page == heap->compact_cursor);
-
-    bits_t *mark_bits, *pin_bits;
-    bits_t bitset;
-    uintptr_t p = page->start;
-
-    mark_bits = page->mark_bits;
-    pin_bits = page->pinned_bits;
-
-    // objects that can be moved are marked and not pinned
-    bitset = (mark_bits[0] & ~pin_bits[0]);
-    bitset >>= NUM_IN_PAGE(p);
-    if (bitset) {
-        if (!gc_compact_plane(objspace, heap, (uintptr_t)p, bitset, page))
-            return false;
-    }
-    p += (BITS_BITLENGTH - NUM_IN_PAGE(p)) * BASE_SLOT_SIZE;
-
-    for (int j = 1; j < HEAP_PAGE_BITMAP_LIMIT; j++) {
-        bitset = (mark_bits[j] & ~pin_bits[j]);
-        if (bitset) {
-            if (!gc_compact_plane(objspace, heap, (uintptr_t)p, bitset, page))
-                return false;
-        }
-        p += BITS_BITLENGTH * BASE_SLOT_SIZE;
-    }
-
-    return true;
-}
-
-static bool
-gc_compact_all_compacted_p(rb_objspace_t *objspace)
-{
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-
-        if (heap->total_pages > 0 &&
-                !gc_compact_heap_cursors_met_p(heap)) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-static void
-gc_sweep_compact(rb_objspace_t *objspace)
-{
-    gc_compact_start(objspace);
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-
-    while (!gc_compact_all_compacted_p(objspace)) {
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rb_heap_t *heap = &heaps[i];
-
-            if (gc_compact_heap_cursors_met_p(heap)) {
-                continue;
-            }
-
-            struct heap_page *start_page = heap->compact_cursor;
-
-            if (!gc_compact_page(objspace, heap, start_page)) {
-                lock_page_body(objspace, start_page->body);
-
-                continue;
-            }
-
-            // If we get here, we've finished moving all objects on the compact_cursor page
-            // So we can lock it and move the cursor on to the next one.
-            lock_page_body(objspace, start_page->body);
-            heap->compact_cursor = ccan_list_prev(&heap->pages, heap->compact_cursor, page_node);
-        }
-    }
-
-    gc_compact_finish(objspace);
-
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-}
-
-static void
-gc_marks_rest(rb_objspace_t *objspace)
-{
-    gc_report(1, objspace, "gc_marks_rest\n");
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        (&heaps[i])->pooled_pages = NULL;
-    }
-
-    if (is_incremental_marking(objspace)) {
-        while (gc_mark_stacked_objects_incremental(objspace, INT_MAX) == FALSE);
-    }
-    else {
-        gc_mark_stacked_objects_all(objspace);
-    }
-
-    gc_marks_finish(objspace);
-}
-
-static bool
-gc_marks_step(rb_objspace_t *objspace, size_t slots)
-{
-    bool marking_finished = false;
-
-    GC_ASSERT(is_marking(objspace));
-    if (gc_mark_stacked_objects_incremental(objspace, slots)) {
-        gc_marks_finish(objspace);
-
-        marking_finished = true;
-    }
-
-    return marking_finished;
-}
-
-static bool
-gc_marks_continue(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    GC_ASSERT(dont_gc_val() == FALSE || objspace->profile.latest_gc_info & GPR_FLAG_METHOD);
-    bool marking_finished = true;
-
-    gc_marking_enter(objspace);
-
-    if (heap->free_pages) {
-        gc_report(2, objspace, "gc_marks_continue: has pooled pages");
-
-        marking_finished = gc_marks_step(objspace, objspace->rincgc.step_slots);
-    }
-    else {
-        gc_report(2, objspace, "gc_marks_continue: no more pooled pages (stack depth: %"PRIdSIZE").\n",
-                  mark_stack_size(&objspace->mark_stack));
-        heap->force_incremental_marking_finish_count++;
-        gc_marks_rest(objspace);
-    }
-
-    gc_marking_exit(objspace);
-
-    return marking_finished;
-}
-
-static void
-gc_marks_start(rb_objspace_t *objspace, int full_mark)
-{
-    /* start marking */
-    gc_report(1, objspace, "gc_marks_start: (%s)\n", full_mark ? "full" : "minor");
-    gc_mode_transition(objspace, gc_mode_marking);
-
-    if (full_mark) {
-        size_t incremental_marking_steps = (objspace->rincgc.pooled_slots / INCREMENTAL_MARK_STEP_ALLOCATIONS) + 1;
-        objspace->rincgc.step_slots = (objspace->marked_slots * 2) / incremental_marking_steps;
-
-        if (0) fprintf(stderr, "objspace->marked_slots: %"PRIdSIZE", "
-                       "objspace->rincgc.pooled_page_num: %"PRIdSIZE", "
-                       "objspace->rincgc.step_slots: %"PRIdSIZE", \n",
-                       objspace->marked_slots, objspace->rincgc.pooled_slots, objspace->rincgc.step_slots);
-        objspace->flags.during_minor_gc = FALSE;
-        if (ruby_enable_autocompact) {
-            objspace->flags.during_compacting |= TRUE;
-        }
-        objspace->profile.major_gc_count++;
-        objspace->rgengc.uncollectible_wb_unprotected_objects = 0;
-        objspace->rgengc.old_objects = 0;
-        objspace->rgengc.last_major_gc = objspace->profile.count;
-        objspace->marked_slots = 0;
-
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rb_heap_t *heap = &heaps[i];
-            rgengc_mark_and_rememberset_clear(objspace, heap);
-            heap_move_pooled_pages_to_free_pages(heap);
-
-            if (objspace->flags.during_compacting) {
-                struct heap_page *page = NULL;
-
-                ccan_list_for_each(&heap->pages, page, page_node) {
-                    page->pinned_slots = 0;
-                }
-            }
-        }
-    }
-    else {
-        objspace->flags.during_minor_gc = TRUE;
-        objspace->marked_slots =
-          objspace->rgengc.old_objects + objspace->rgengc.uncollectible_wb_unprotected_objects; /* uncollectible objects are marked already */
-        objspace->profile.minor_gc_count++;
-
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rgengc_rememberset_mark(objspace, &heaps[i]);
-        }
-    }
-
-    mark_roots(objspace, NULL);
-
-    gc_report(1, objspace, "gc_marks_start: (%s) end, stack in %"PRIdSIZE"\n",
-              full_mark ? "full" : "minor", mark_stack_size(&objspace->mark_stack));
-}
-
-static bool
-gc_marks(rb_objspace_t *objspace, int full_mark)
-{
-    gc_prof_mark_timer_start(objspace);
-    gc_marking_enter(objspace);
-
-    bool marking_finished = false;
-
-    /* setup marking */
-
-    gc_marks_start(objspace, full_mark);
-    if (!is_incremental_marking(objspace)) {
-        gc_marks_rest(objspace);
-        marking_finished = true;
-    }
-
-#if RGENGC_PROFILE > 0
-    if (gc_prof_record(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->old_objects = objspace->rgengc.old_objects;
-    }
-#endif
-
-    gc_marking_exit(objspace);
-    gc_prof_mark_timer_stop(objspace);
-
-    return marking_finished;
-}
-
-/* RGENGC */
-
-static void
-gc_report_body(int level, rb_objspace_t *objspace, const char *fmt, ...)
-{
-    if (level <= RGENGC_DEBUG) {
-        char buf[1024];
-        FILE *out = stderr;
-        va_list args;
-        const char *status = " ";
-
-        if (during_gc) {
-            status = is_full_marking(objspace) ? "+" : "-";
-        }
-        else {
-            if (is_lazy_sweeping(objspace)) {
-                status = "S";
-            }
-            if (is_incremental_marking(objspace)) {
-                status = "M";
-            }
-        }
-
-        va_start(args, fmt);
-        vsnprintf(buf, 1024, fmt, args);
-        va_end(args);
-
-        fprintf(out, "%s|", status);
-        fputs(buf, out);
-    }
-}
-
-/* bit operations */
-
-static int
-rgengc_remembersetbits_set(rb_objspace_t *objspace, VALUE obj)
-{
-    struct heap_page *page = GET_HEAP_PAGE(obj);
-    bits_t *bits = &page->remembered_bits[0];
-
-    if (MARKED_IN_BITMAP(bits, obj)) {
-        return FALSE;
-    }
-    else {
-        page->flags.has_remembered_objects = TRUE;
-        MARK_IN_BITMAP(bits, obj);
-        return TRUE;
-    }
-}
-
-/* wb, etc */
-
-/* return FALSE if already remembered */
-static int
-rgengc_remember(rb_objspace_t *objspace, VALUE obj)
-{
-    gc_report(6, objspace, "rgengc_remember: %s %s\n", rb_obj_info(obj),
-              RVALUE_REMEMBERED(objspace, obj) ? "was already remembered" : "is remembered now");
-
-    check_rvalue_consistency(objspace, obj);
-
-    if (RGENGC_CHECK_MODE) {
-        if (RVALUE_WB_UNPROTECTED(objspace, obj)) rb_bug("rgengc_remember: %s is not wb protected.", rb_obj_info(obj));
-    }
-
-#if RGENGC_PROFILE > 0
-    if (!RVALUE_REMEMBERED(objspace, obj)) {
-        if (RVALUE_WB_UNPROTECTED(objspace, obj) == 0) {
-            objspace->profile.total_remembered_normal_object_count++;
-#if RGENGC_PROFILE >= 2
-            objspace->profile.remembered_normal_object_count_types[BUILTIN_TYPE(obj)]++;
-#endif
-        }
-    }
-#endif /* RGENGC_PROFILE > 0 */
-
-    return rgengc_remembersetbits_set(objspace, obj);
-}
-
-#ifndef PROFILE_REMEMBERSET_MARK
-#define PROFILE_REMEMBERSET_MARK 0
-#endif
-
-static inline void
-rgengc_rememberset_mark_plane(rb_objspace_t *objspace, uintptr_t p, bits_t bitset)
-{
-    if (bitset) {
-        do {
-            if (bitset & 1) {
-                VALUE obj = (VALUE)p;
-                gc_report(2, objspace, "rgengc_rememberset_mark: mark %s\n", rb_obj_info(obj));
-                GC_ASSERT(RVALUE_UNCOLLECTIBLE(objspace, obj));
-                GC_ASSERT(RVALUE_OLD_P(objspace, obj) || RVALUE_WB_UNPROTECTED(objspace, obj));
-
-                gc_mark_children(objspace, obj);
-            }
-            p += BASE_SLOT_SIZE;
-            bitset >>= 1;
-        } while (bitset);
-    }
-}
-
-static void
-rgengc_rememberset_mark(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    size_t j;
-    struct heap_page *page = 0;
-#if PROFILE_REMEMBERSET_MARK
-    int has_old = 0, has_shady = 0, has_both = 0, skip = 0;
-#endif
-    gc_report(1, objspace, "rgengc_rememberset_mark: start\n");
-
-    ccan_list_for_each(&heap->pages, page, page_node) {
-        if (page->flags.has_remembered_objects | page->flags.has_uncollectible_wb_unprotected_objects) {
-            uintptr_t p = page->start;
-            bits_t bitset, bits[HEAP_PAGE_BITMAP_LIMIT];
-            bits_t *remembered_bits = page->remembered_bits;
-            bits_t *uncollectible_bits = page->uncollectible_bits;
-            bits_t *wb_unprotected_bits = page->wb_unprotected_bits;
-#if PROFILE_REMEMBERSET_MARK
-            if (page->flags.has_remembered_objects && page->flags.has_uncollectible_wb_unprotected_objects) has_both++;
-            else if (page->flags.has_remembered_objects) has_old++;
-            else if (page->flags.has_uncollectible_wb_unprotected_objects) has_shady++;
-#endif
-            for (j=0; j<HEAP_PAGE_BITMAP_LIMIT; j++) {
-                bits[j] = remembered_bits[j] | (uncollectible_bits[j] & wb_unprotected_bits[j]);
-                remembered_bits[j] = 0;
-            }
-            page->flags.has_remembered_objects = FALSE;
-
-            bitset = bits[0];
-            bitset >>= NUM_IN_PAGE(p);
-            rgengc_rememberset_mark_plane(objspace, p, bitset);
-            p += (BITS_BITLENGTH - NUM_IN_PAGE(p)) * BASE_SLOT_SIZE;
-
-            for (j=1; j < HEAP_PAGE_BITMAP_LIMIT; j++) {
-                bitset = bits[j];
-                rgengc_rememberset_mark_plane(objspace, p, bitset);
-                p += BITS_BITLENGTH * BASE_SLOT_SIZE;
-            }
-        }
-#if PROFILE_REMEMBERSET_MARK
-        else {
-            skip++;
-        }
-#endif
-    }
-
-#if PROFILE_REMEMBERSET_MARK
-    fprintf(stderr, "%d\t%d\t%d\t%d\n", has_both, has_old, has_shady, skip);
-#endif
-    gc_report(1, objspace, "rgengc_rememberset_mark: finished\n");
-}
-
-static void
-rgengc_mark_and_rememberset_clear(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    struct heap_page *page = 0;
-
-    ccan_list_for_each(&heap->pages, page, page_node) {
-        memset(&page->mark_bits[0],       0, HEAP_PAGE_BITMAP_SIZE);
-        memset(&page->uncollectible_bits[0], 0, HEAP_PAGE_BITMAP_SIZE);
-        memset(&page->marking_bits[0],    0, HEAP_PAGE_BITMAP_SIZE);
-        memset(&page->remembered_bits[0], 0, HEAP_PAGE_BITMAP_SIZE);
-        memset(&page->pinned_bits[0],     0, HEAP_PAGE_BITMAP_SIZE);
-        page->flags.has_uncollectible_wb_unprotected_objects = FALSE;
-        page->flags.has_remembered_objects = FALSE;
-    }
-}
-
-/* RGENGC: APIs */
-
-NOINLINE(static void gc_writebarrier_generational(VALUE a, VALUE b, rb_objspace_t *objspace));
-
-static void
-gc_writebarrier_generational(VALUE a, VALUE b, rb_objspace_t *objspace)
-{
-    if (RGENGC_CHECK_MODE) {
-        if (!RVALUE_OLD_P(objspace, a)) rb_bug("gc_writebarrier_generational: %s is not an old object.", rb_obj_info(a));
-        if ( RVALUE_OLD_P(objspace, b)) rb_bug("gc_writebarrier_generational: %s is an old object.", rb_obj_info(b));
-        if (is_incremental_marking(objspace)) rb_bug("gc_writebarrier_generational: called while incremental marking: %s -> %s", rb_obj_info(a), rb_obj_info(b));
-    }
-
-    /* mark `a' and remember (default behavior) */
-    if (!RVALUE_REMEMBERED(objspace, a)) {
-        int lev = rb_gc_vm_lock_no_barrier();
-        {
-            rgengc_remember(objspace, a);
-        }
-        rb_gc_vm_unlock_no_barrier(lev);
-
-        gc_report(1, objspace, "gc_writebarrier_generational: %s (remembered) -> %s\n", rb_obj_info(a), rb_obj_info(b));
-    }
-
-    check_rvalue_consistency(objspace, a);
-    check_rvalue_consistency(objspace, b);
-}
-
-static void
-gc_mark_from(rb_objspace_t *objspace, VALUE obj, VALUE parent)
-{
-    gc_mark_set_parent(objspace, parent);
-    rgengc_check_relation(objspace, obj);
-    if (gc_mark_set(objspace, obj) == FALSE) return;
-    gc_aging(objspace, obj);
-    gc_grey(objspace, obj);
-}
-
-NOINLINE(static void gc_writebarrier_incremental(VALUE a, VALUE b, rb_objspace_t *objspace));
-
-static void
-gc_writebarrier_incremental(VALUE a, VALUE b, rb_objspace_t *objspace)
-{
-    gc_report(2, objspace, "gc_writebarrier_incremental: [LG] %p -> %s\n", (void *)a, rb_obj_info(b));
-
-    if (RVALUE_BLACK_P(objspace, a)) {
-        if (RVALUE_WHITE_P(objspace, b)) {
-            if (!RVALUE_WB_UNPROTECTED(objspace, a)) {
-                gc_report(2, objspace, "gc_writebarrier_incremental: [IN] %p -> %s\n", (void *)a, rb_obj_info(b));
-                gc_mark_from(objspace, b, a);
-            }
-        }
-        else if (RVALUE_OLD_P(objspace, a) && !RVALUE_OLD_P(objspace, b)) {
-            rgengc_remember(objspace, a);
-        }
-
-        if (RB_UNLIKELY(objspace->flags.during_compacting)) {
-            MARK_IN_BITMAP(GET_HEAP_PINNED_BITS(b), b);
-        }
-    }
-}
-
-void
-rb_gc_impl_writebarrier(void *objspace_ptr, VALUE a, VALUE b)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (RGENGC_CHECK_MODE) {
-        if (SPECIAL_CONST_P(a)) rb_bug("rb_gc_writebarrier: a is special const: %"PRIxVALUE, a);
-        if (SPECIAL_CONST_P(b)) rb_bug("rb_gc_writebarrier: b is special const: %"PRIxVALUE, b);
-    }
-
-    GC_ASSERT(RB_BUILTIN_TYPE(a) != T_NONE);
-    GC_ASSERT(RB_BUILTIN_TYPE(a) != T_MOVED);
-    GC_ASSERT(RB_BUILTIN_TYPE(a) != T_ZOMBIE);
-    GC_ASSERT(RB_BUILTIN_TYPE(b) != T_NONE);
-    GC_ASSERT(RB_BUILTIN_TYPE(b) != T_MOVED);
-    GC_ASSERT(RB_BUILTIN_TYPE(b) != T_ZOMBIE);
-
-  retry:
-    if (!is_incremental_marking(objspace)) {
-        if (!RVALUE_OLD_P(objspace, a) || RVALUE_OLD_P(objspace, b)) {
-            // do nothing
-        }
-        else {
-            gc_writebarrier_generational(a, b, objspace);
-        }
-    }
-    else {
-        bool retry = false;
-        /* slow path */
-        int lev = rb_gc_vm_lock_no_barrier();
-        {
-            if (is_incremental_marking(objspace)) {
-                gc_writebarrier_incremental(a, b, objspace);
-            }
-            else {
-                retry = true;
-            }
-        }
-        rb_gc_vm_unlock_no_barrier(lev);
-
-        if (retry) goto retry;
-    }
-    return;
-}
-
-void
-rb_gc_impl_writebarrier_unprotect(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (RVALUE_WB_UNPROTECTED(objspace, obj)) {
-        return;
-    }
-    else {
-        gc_report(2, objspace, "rb_gc_writebarrier_unprotect: %s %s\n", rb_obj_info(obj),
-                  RVALUE_REMEMBERED(objspace, obj) ? " (already remembered)" : "");
-
-        unsigned int lev = rb_gc_vm_lock_no_barrier();
-        {
-            if (RVALUE_OLD_P(objspace, obj)) {
-                gc_report(1, objspace, "rb_gc_writebarrier_unprotect: %s\n", rb_obj_info(obj));
-                RVALUE_DEMOTE(objspace, obj);
-                gc_mark_set(objspace, obj);
-                gc_remember_unprotected(objspace, obj);
-
-#if RGENGC_PROFILE
-                objspace->profile.total_shade_operation_count++;
-#if RGENGC_PROFILE >= 2
-                objspace->profile.shade_operation_count_types[BUILTIN_TYPE(obj)]++;
-#endif /* RGENGC_PROFILE >= 2 */
-#endif /* RGENGC_PROFILE */
-            }
-            else {
-                RVALUE_AGE_RESET(obj);
-            }
-
-            RB_DEBUG_COUNTER_INC(obj_wb_unprotect);
-            MARK_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(obj), obj);
-        }
-        rb_gc_vm_unlock_no_barrier(lev);
-    }
-}
-
-void
-rb_gc_impl_copy_attributes(void *objspace_ptr, VALUE dest, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (RVALUE_WB_UNPROTECTED(objspace, obj)) {
-        rb_gc_impl_writebarrier_unprotect(objspace, dest);
-    }
-    rb_gc_impl_copy_finalizer(objspace, dest, obj);
-}
-
-const char *
-rb_gc_impl_active_gc_name(void)
-{
-    return "default";
-}
-
-void
-rb_gc_impl_writebarrier_remember(void *objspace_ptr, VALUE obj)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    gc_report(1, objspace, "rb_gc_writebarrier_remember: %s\n", rb_obj_info(obj));
-
-    if (is_incremental_marking(objspace)) {
-        if (RVALUE_BLACK_P(objspace, obj)) {
-            gc_grey(objspace, obj);
-        }
-    }
-    else {
-        if (RVALUE_OLD_P(objspace, obj)) {
-            rgengc_remember(objspace, obj);
-        }
-    }
-}
-
-// TODO: rearchitect this function to work for a generic GC
-size_t
-rb_gc_impl_obj_flags(void *objspace_ptr, VALUE obj, ID* flags, size_t max)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    size_t n = 0;
-    static ID ID_marked;
-    static ID ID_wb_protected, ID_old, ID_marking, ID_uncollectible, ID_pinned;
-
-    if (!ID_marked) {
-#define I(s) ID_##s = rb_intern(#s);
-        I(marked);
-        I(wb_protected);
-        I(old);
-        I(marking);
-        I(uncollectible);
-        I(pinned);
-#undef I
-    }
-
-    if (RVALUE_WB_UNPROTECTED(objspace, obj) == 0 && n < max)                   flags[n++] = ID_wb_protected;
-    if (RVALUE_OLD_P(objspace, obj) && n < max)                                 flags[n++] = ID_old;
-    if (RVALUE_UNCOLLECTIBLE(objspace, obj) && n < max)                         flags[n++] = ID_uncollectible;
-    if (RVALUE_MARKING(objspace, obj) && n < max) flags[n++] = ID_marking;
-    if (RVALUE_MARKED(objspace, obj) && n < max)    flags[n++] = ID_marked;
-    if (RVALUE_PINNED(objspace, obj) && n < max)  flags[n++] = ID_pinned;
-    return n;
-}
-
-void *
-rb_gc_impl_ractor_cache_alloc(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    objspace->live_ractor_cache_count++;
-
-    return calloc1(sizeof(rb_ractor_newobj_cache_t));
-}
-
-void
-rb_gc_impl_ractor_cache_free(void *objspace_ptr, void *cache)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    objspace->live_ractor_cache_count--;
-
-    gc_ractor_newobj_cache_clear(cache, NULL);
-    free(cache);
-}
-
-static void
-heap_ready_to_gc(rb_objspace_t *objspace, rb_heap_t *heap)
-{
-    if (!heap->free_pages) {
-        if (!heap_page_allocate_and_initialize(objspace, heap)) {
-            objspace->heap_pages.allocatable_slots = 1;
-            heap_page_allocate_and_initialize(objspace, heap);
-        }
-    }
-}
-
-static int
-ready_to_gc(rb_objspace_t *objspace)
-{
-    if (dont_gc_val() || during_gc || ruby_disable_gc) {
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            rb_heap_t *heap = &heaps[i];
-            heap_ready_to_gc(objspace, heap);
-        }
-        return FALSE;
-    }
-    else {
-        return TRUE;
-    }
-}
-
-static void
-gc_reset_malloc_info(rb_objspace_t *objspace, bool full_mark)
-{
-    gc_prof_set_malloc_info(objspace);
-    {
-        size_t inc = RUBY_ATOMIC_SIZE_EXCHANGE(malloc_increase, 0);
-        size_t old_limit = malloc_limit;
-
-        if (inc > malloc_limit) {
-            malloc_limit = (size_t)(inc * gc_params.malloc_limit_growth_factor);
-            if (malloc_limit > gc_params.malloc_limit_max) {
-                malloc_limit = gc_params.malloc_limit_max;
-            }
-        }
-        else {
-            malloc_limit = (size_t)(malloc_limit * 0.98); /* magic number */
-            if (malloc_limit < gc_params.malloc_limit_min) {
-                malloc_limit = gc_params.malloc_limit_min;
-            }
-        }
-
-        if (0) {
-            if (old_limit != malloc_limit) {
-                fprintf(stderr, "[%"PRIuSIZE"] malloc_limit: %"PRIuSIZE" -> %"PRIuSIZE"\n",
-                        rb_gc_count(), old_limit, malloc_limit);
-            }
-            else {
-                fprintf(stderr, "[%"PRIuSIZE"] malloc_limit: not changed (%"PRIuSIZE")\n",
-                        rb_gc_count(), malloc_limit);
-            }
-        }
-    }
-
-    /* reset oldmalloc info */
-#if RGENGC_ESTIMATE_OLDMALLOC
-    if (!full_mark) {
-        if (objspace->rgengc.oldmalloc_increase > objspace->rgengc.oldmalloc_increase_limit) {
-            gc_needs_major_flags |= GPR_FLAG_MAJOR_BY_OLDMALLOC;
-            objspace->rgengc.oldmalloc_increase_limit =
-              (size_t)(objspace->rgengc.oldmalloc_increase_limit * gc_params.oldmalloc_limit_growth_factor);
-
-            if (objspace->rgengc.oldmalloc_increase_limit > gc_params.oldmalloc_limit_max) {
-                objspace->rgengc.oldmalloc_increase_limit = gc_params.oldmalloc_limit_max;
-            }
-        }
-
-        if (0) fprintf(stderr, "%"PRIdSIZE"\t%d\t%"PRIuSIZE"\t%"PRIuSIZE"\t%"PRIdSIZE"\n",
-                       rb_gc_count(),
-                       gc_needs_major_flags,
-                       objspace->rgengc.oldmalloc_increase,
-                       objspace->rgengc.oldmalloc_increase_limit,
-                       gc_params.oldmalloc_limit_max);
-    }
-    else {
-        /* major GC */
-        objspace->rgengc.oldmalloc_increase = 0;
-
-        if ((objspace->profile.latest_gc_info & GPR_FLAG_MAJOR_BY_OLDMALLOC) == 0) {
-            objspace->rgengc.oldmalloc_increase_limit =
-              (size_t)(objspace->rgengc.oldmalloc_increase_limit / ((gc_params.oldmalloc_limit_growth_factor - 1)/10 + 1));
-            if (objspace->rgengc.oldmalloc_increase_limit < gc_params.oldmalloc_limit_min) {
-                objspace->rgengc.oldmalloc_increase_limit = gc_params.oldmalloc_limit_min;
-            }
-        }
-    }
-#endif
-}
-
-static int
-garbage_collect(rb_objspace_t *objspace, unsigned int reason)
-{
-    int ret;
-
-    int lev = rb_gc_vm_lock();
-    {
-#if GC_PROFILE_MORE_DETAIL
-        objspace->profile.prepare_time = getrusage_time();
-#endif
-
-        gc_rest(objspace);
-
-#if GC_PROFILE_MORE_DETAIL
-        objspace->profile.prepare_time = getrusage_time() - objspace->profile.prepare_time;
-#endif
-
-        ret = gc_start(objspace, reason);
-    }
-    rb_gc_vm_unlock(lev);
-
-    return ret;
-}
-
-static int
-gc_start(rb_objspace_t *objspace, unsigned int reason)
-{
-    unsigned int do_full_mark = !!(reason & GPR_FLAG_FULL_MARK);
-
-    /* reason may be clobbered, later, so keep set immediate_sweep here */
-    objspace->flags.immediate_sweep = !!(reason & GPR_FLAG_IMMEDIATE_SWEEP);
-
-    if (!rb_darray_size(objspace->heap_pages.sorted)) return TRUE; /* heap is not ready */
-    if (!(reason & GPR_FLAG_METHOD) && !ready_to_gc(objspace)) return TRUE; /* GC is not allowed */
-
-    GC_ASSERT(gc_mode(objspace) == gc_mode_none);
-    GC_ASSERT(!is_lazy_sweeping(objspace));
-    GC_ASSERT(!is_incremental_marking(objspace));
-
-    unsigned int lock_lev;
-    gc_enter(objspace, gc_enter_event_start, &lock_lev);
-
-#if RGENGC_CHECK_MODE >= 2
-    gc_verify_internal_consistency(objspace);
-#endif
-
-    if (ruby_gc_stressful) {
-        int flag = FIXNUM_P(ruby_gc_stress_mode) ? FIX2INT(ruby_gc_stress_mode) : 0;
-
-        if ((flag & (1 << gc_stress_no_major)) == 0) {
-            do_full_mark = TRUE;
-        }
-
-        objspace->flags.immediate_sweep = !(flag & (1<<gc_stress_no_immediate_sweep));
-    }
-
-    if (gc_needs_major_flags) {
-        reason |= gc_needs_major_flags;
-        do_full_mark = TRUE;
-    }
-
-    /* if major gc has been disabled, never do a full mark */
-    if (!gc_config_full_mark_val) {
-        do_full_mark = FALSE;
-    }
-    gc_needs_major_flags = GPR_FLAG_NONE;
-
-    if (do_full_mark && (reason & GPR_FLAG_MAJOR_MASK) == 0) {
-        reason |= GPR_FLAG_MAJOR_BY_FORCE; /* GC by CAPI, METHOD, and so on. */
-    }
-
-    if (objspace->flags.dont_incremental ||
-            reason & GPR_FLAG_IMMEDIATE_MARK ||
-            ruby_gc_stressful) {
-        objspace->flags.during_incremental_marking = FALSE;
-    }
-    else {
-        objspace->flags.during_incremental_marking = do_full_mark;
-    }
-
-    /* Explicitly enable compaction (GC.compact) */
-    if (do_full_mark && ruby_enable_autocompact) {
-        objspace->flags.during_compacting = TRUE;
-#if RGENGC_CHECK_MODE
-        objspace->rcompactor.compare_func = ruby_autocompact_compare_func;
-#endif
-    }
-    else {
-        objspace->flags.during_compacting = !!(reason & GPR_FLAG_COMPACT);
-    }
-
-    if (!GC_ENABLE_LAZY_SWEEP || objspace->flags.dont_incremental) {
-        objspace->flags.immediate_sweep = TRUE;
-    }
-
-    if (objspace->flags.immediate_sweep) reason |= GPR_FLAG_IMMEDIATE_SWEEP;
-
-    gc_report(1, objspace, "gc_start(reason: %x) => %u, %d, %d\n",
-              reason,
-              do_full_mark, !is_incremental_marking(objspace), objspace->flags.immediate_sweep);
-
-#if USE_DEBUG_COUNTER
-    RB_DEBUG_COUNTER_INC(gc_count);
-
-    if (reason & GPR_FLAG_MAJOR_MASK) {
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_major_nofree, reason & GPR_FLAG_MAJOR_BY_NOFREE);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_major_oldgen, reason & GPR_FLAG_MAJOR_BY_OLDGEN);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_major_shady,  reason & GPR_FLAG_MAJOR_BY_SHADY);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_major_force,  reason & GPR_FLAG_MAJOR_BY_FORCE);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_major_oldmalloc, reason & GPR_FLAG_MAJOR_BY_OLDMALLOC);
-#endif
-    }
-    else {
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_minor_newobj, reason & GPR_FLAG_NEWOBJ);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_minor_malloc, reason & GPR_FLAG_MALLOC);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_minor_method, reason & GPR_FLAG_METHOD);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_minor_capi,   reason & GPR_FLAG_CAPI);
-        (void)RB_DEBUG_COUNTER_INC_IF(gc_minor_stress, reason & GPR_FLAG_STRESS);
-    }
-#endif
-
-    objspace->profile.count++;
-    objspace->profile.latest_gc_info = reason;
-    objspace->profile.total_allocated_objects_at_gc_start = total_allocated_objects(objspace);
-    objspace->profile.heap_used_at_gc_start = rb_darray_size(objspace->heap_pages.sorted);
-    objspace->profile.weak_references_count = 0;
-    objspace->profile.retained_weak_references_count = 0;
-    gc_prof_setup_new_record(objspace, reason);
-    gc_reset_malloc_info(objspace, do_full_mark);
-
-    rb_gc_event_hook(0, RUBY_INTERNAL_EVENT_GC_START);
-
-    GC_ASSERT(during_gc);
-
-    gc_prof_timer_start(objspace);
-    {
-        if (gc_marks(objspace, do_full_mark)) {
-            gc_sweep(objspace);
-        }
-    }
-    gc_prof_timer_stop(objspace);
-
-    gc_exit(objspace, gc_enter_event_start, &lock_lev);
-    return TRUE;
-}
-
-static void
-gc_rest(rb_objspace_t *objspace)
-{
-    if (is_incremental_marking(objspace) || is_lazy_sweeping(objspace)) {
-        unsigned int lock_lev;
-        gc_enter(objspace, gc_enter_event_rest, &lock_lev);
-
-        if (RGENGC_CHECK_MODE >= 2) gc_verify_internal_consistency(objspace);
-
-        if (is_incremental_marking(objspace)) {
-            gc_marking_enter(objspace);
-            gc_marks_rest(objspace);
-            gc_marking_exit(objspace);
-
-            gc_sweep(objspace);
-        }
-
-        if (is_lazy_sweeping(objspace)) {
-            gc_sweeping_enter(objspace);
-            gc_sweep_rest(objspace);
-            gc_sweeping_exit(objspace);
-        }
-
-        gc_exit(objspace, gc_enter_event_rest, &lock_lev);
-    }
-}
-
-struct objspace_and_reason {
-    rb_objspace_t *objspace;
-    unsigned int reason;
-};
-
-static void
-gc_current_status_fill(rb_objspace_t *objspace, char *buff)
-{
-    int i = 0;
-    if (is_marking(objspace)) {
-        buff[i++] = 'M';
-        if (is_full_marking(objspace))        buff[i++] = 'F';
-        if (is_incremental_marking(objspace)) buff[i++] = 'I';
-    }
-    else if (is_sweeping(objspace)) {
-        buff[i++] = 'S';
-        if (is_lazy_sweeping(objspace))      buff[i++] = 'L';
-    }
-    else {
-        buff[i++] = 'N';
-    }
-    buff[i] = '\0';
-}
-
-static const char *
-gc_current_status(rb_objspace_t *objspace)
-{
-    static char buff[0x10];
-    gc_current_status_fill(objspace, buff);
-    return buff;
-}
-
-#if PRINT_ENTER_EXIT_TICK
-
-static tick_t last_exit_tick;
-static tick_t enter_tick;
-static int enter_count = 0;
-static char last_gc_status[0x10];
-
-static inline void
-gc_record(rb_objspace_t *objspace, int direction, const char *event)
-{
-    if (direction == 0) { /* enter */
-        enter_count++;
-        enter_tick = tick();
-        gc_current_status_fill(objspace, last_gc_status);
-    }
-    else { /* exit */
-        tick_t exit_tick = tick();
-        char current_gc_status[0x10];
-        gc_current_status_fill(objspace, current_gc_status);
-#if 1
-        /* [last mutator time] [gc time] [event] */
-        fprintf(stderr, "%"PRItick"\t%"PRItick"\t%s\t[%s->%s|%c]\n",
-                enter_tick - last_exit_tick,
-                exit_tick - enter_tick,
-                event,
-                last_gc_status, current_gc_status,
-                (objspace->profile.latest_gc_info & GPR_FLAG_MAJOR_MASK) ? '+' : '-');
-        last_exit_tick = exit_tick;
-#else
-        /* [enter_tick] [gc time] [event] */
-        fprintf(stderr, "%"PRItick"\t%"PRItick"\t%s\t[%s->%s|%c]\n",
-                enter_tick,
-                exit_tick - enter_tick,
-                event,
-                last_gc_status, current_gc_status,
-                (objspace->profile.latest_gc_info & GPR_FLAG_MAJOR_MASK) ? '+' : '-');
-#endif
-    }
-}
-#else /* PRINT_ENTER_EXIT_TICK */
-static inline void
-gc_record(rb_objspace_t *objspace, int direction, const char *event)
-{
-    /* null */
-}
-#endif /* PRINT_ENTER_EXIT_TICK */
-
-static const char *
-gc_enter_event_cstr(enum gc_enter_event event)
-{
-    switch (event) {
-      case gc_enter_event_start: return "start";
-      case gc_enter_event_continue: return "continue";
-      case gc_enter_event_rest: return "rest";
-      case gc_enter_event_finalizer: return "finalizer";
-    }
-    return NULL;
-}
-
-static void
-gc_enter_count(enum gc_enter_event event)
-{
-    switch (event) {
-      case gc_enter_event_start:          RB_DEBUG_COUNTER_INC(gc_enter_start); break;
-      case gc_enter_event_continue:       RB_DEBUG_COUNTER_INC(gc_enter_continue); break;
-      case gc_enter_event_rest:           RB_DEBUG_COUNTER_INC(gc_enter_rest); break;
-      case gc_enter_event_finalizer:      RB_DEBUG_COUNTER_INC(gc_enter_finalizer); break;
-    }
-}
-
-static bool current_process_time(struct timespec *ts);
-
-static void
-gc_clock_start(struct timespec *ts)
-{
-    if (!current_process_time(ts)) {
-        ts->tv_sec = 0;
-        ts->tv_nsec = 0;
-    }
-}
-
-static unsigned long long
-gc_clock_end(struct timespec *ts)
-{
-    struct timespec end_time;
-
-    if ((ts->tv_sec > 0 || ts->tv_nsec > 0) &&
-            current_process_time(&end_time) &&
-            end_time.tv_sec >= ts->tv_sec) {
-        return (unsigned long long)(end_time.tv_sec - ts->tv_sec) * (1000 * 1000 * 1000) +
-                    (end_time.tv_nsec - ts->tv_nsec);
-    }
-
-    return 0;
-}
-
-static inline void
-gc_enter(rb_objspace_t *objspace, enum gc_enter_event event, unsigned int *lock_lev)
-{
-    *lock_lev = rb_gc_vm_lock();
-
-    switch (event) {
-      case gc_enter_event_rest:
-        if (!is_marking(objspace)) break;
-        // fall through
-      case gc_enter_event_start:
-      case gc_enter_event_continue:
-        // stop other ractors
-        rb_gc_vm_barrier();
-        break;
-      default:
-        break;
-    }
-
-    gc_enter_count(event);
-    if (RB_UNLIKELY(during_gc != 0)) rb_bug("during_gc != 0");
-    if (RGENGC_CHECK_MODE >= 3) gc_verify_internal_consistency(objspace);
-
-    during_gc = TRUE;
-    RUBY_DEBUG_LOG("%s (%s)",gc_enter_event_cstr(event), gc_current_status(objspace));
-    gc_report(1, objspace, "gc_enter: %s [%s]\n", gc_enter_event_cstr(event), gc_current_status(objspace));
-    gc_record(objspace, 0, gc_enter_event_cstr(event));
-
-    rb_gc_event_hook(0, RUBY_INTERNAL_EVENT_GC_ENTER);
-}
-
-static inline void
-gc_exit(rb_objspace_t *objspace, enum gc_enter_event event, unsigned int *lock_lev)
-{
-    GC_ASSERT(during_gc != 0);
-
-    rb_gc_event_hook(0, RUBY_INTERNAL_EVENT_GC_EXIT);
-
-    gc_record(objspace, 1, gc_enter_event_cstr(event));
-    RUBY_DEBUG_LOG("%s (%s)", gc_enter_event_cstr(event), gc_current_status(objspace));
-    gc_report(1, objspace, "gc_exit: %s [%s]\n", gc_enter_event_cstr(event), gc_current_status(objspace));
-    during_gc = FALSE;
-
-    rb_gc_vm_unlock(*lock_lev);
-}
-
-#ifndef MEASURE_GC
-#define MEASURE_GC (objspace->flags.measure_gc)
-#endif
-
-static void
-gc_marking_enter(rb_objspace_t *objspace)
-{
-    GC_ASSERT(during_gc != 0);
-
-    if (MEASURE_GC) {
-        gc_clock_start(&objspace->profile.marking_start_time);
-    }
-}
-
-static void
-gc_marking_exit(rb_objspace_t *objspace)
-{
-    GC_ASSERT(during_gc != 0);
-
-    if (MEASURE_GC) {
-        objspace->profile.marking_time_ns += gc_clock_end(&objspace->profile.marking_start_time);
-    }
-}
-
-static void
-gc_sweeping_enter(rb_objspace_t *objspace)
-{
-    GC_ASSERT(during_gc != 0);
-
-    if (MEASURE_GC) {
-        gc_clock_start(&objspace->profile.sweeping_start_time);
-    }
-}
-
-static void
-gc_sweeping_exit(rb_objspace_t *objspace)
-{
-    GC_ASSERT(during_gc != 0);
-
-    if (MEASURE_GC) {
-        objspace->profile.sweeping_time_ns += gc_clock_end(&objspace->profile.sweeping_start_time);
-    }
-}
-
-static void *
-gc_with_gvl(void *ptr)
-{
-    struct objspace_and_reason *oar = (struct objspace_and_reason *)ptr;
-    return (void *)(VALUE)garbage_collect(oar->objspace, oar->reason);
-}
-
-int ruby_thread_has_gvl_p(void);
-
-static int
-garbage_collect_with_gvl(rb_objspace_t *objspace, unsigned int reason)
-{
-    if (dont_gc_val()) return TRUE;
-    if (ruby_thread_has_gvl_p()) {
-        return garbage_collect(objspace, reason);
-    }
-    else {
-        if (ruby_native_thread_p()) {
-            struct objspace_and_reason oar;
-            oar.objspace = objspace;
-            oar.reason = reason;
-            return (int)(VALUE)rb_thread_call_with_gvl(gc_with_gvl, (void *)&oar);
-        }
-        else {
-            /* no ruby thread */
-            fprintf(stderr, "[FATAL] failed to allocate memory\n");
-            exit(EXIT_FAILURE);
-        }
-    }
-}
-
-static int
-gc_set_candidate_object_i(void *vstart, void *vend, size_t stride, void *data)
-{
-    rb_objspace_t *objspace = (rb_objspace_t *)data;
-
-    VALUE v = (VALUE)vstart;
-    for (; v != (VALUE)vend; v += stride) {
-        asan_unpoisoning_object(v) {
-            switch (BUILTIN_TYPE(v)) {
-              case T_NONE:
-              case T_ZOMBIE:
-                break;
-              default:
-                rb_gc_prepare_heap_process_object(v);
-                if (!RVALUE_OLD_P(objspace, v) && !RVALUE_WB_UNPROTECTED(objspace, v)) {
-                    RVALUE_AGE_SET_CANDIDATE(objspace, v);
-                }
-            }
-        }
-    }
-
-    return 0;
-}
-
-void
-rb_gc_impl_start(void *objspace_ptr, bool full_mark, bool immediate_mark, bool immediate_sweep, bool compact)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    unsigned int reason = (GPR_FLAG_FULL_MARK |
-                           GPR_FLAG_IMMEDIATE_MARK |
-                           GPR_FLAG_IMMEDIATE_SWEEP |
-                           GPR_FLAG_METHOD);
-
-    int full_marking_p = gc_config_full_mark_val;
-    gc_config_full_mark_set(TRUE);
-
-    /* For now, compact implies full mark / sweep, so ignore other flags */
-    if (compact) {
-        GC_ASSERT(GC_COMPACTION_SUPPORTED);
-
-        reason |= GPR_FLAG_COMPACT;
-    }
-    else {
-        if (!full_mark)       reason &= ~GPR_FLAG_FULL_MARK;
-        if (!immediate_mark)  reason &= ~GPR_FLAG_IMMEDIATE_MARK;
-        if (!immediate_sweep) reason &= ~GPR_FLAG_IMMEDIATE_SWEEP;
-    }
-
-    garbage_collect(objspace, reason);
-    gc_finalize_deferred(objspace);
-
-    gc_config_full_mark_set(full_marking_p);
-}
-
-void
-rb_gc_impl_prepare_heap(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    size_t orig_total_slots = objspace_available_slots(objspace);
-    size_t orig_allocatable_slots = objspace->heap_pages.allocatable_slots;
-
-    rb_gc_impl_each_objects(objspace, gc_set_candidate_object_i, objspace_ptr);
-
-    double orig_max_free_slots = gc_params.heap_free_slots_max_ratio;
-    /* Ensure that all empty pages are moved onto empty_pages. */
-    gc_params.heap_free_slots_max_ratio = 0.0;
-    rb_gc_impl_start(objspace, true, true, true, true);
-    gc_params.heap_free_slots_max_ratio = orig_max_free_slots;
-
-    objspace->heap_pages.allocatable_slots = 0;
-    heap_pages_free_unused_pages(objspace_ptr);
-    GC_ASSERT(objspace->empty_pages_count == 0);
-    objspace->heap_pages.allocatable_slots = orig_allocatable_slots;
-
-    size_t total_slots = objspace_available_slots(objspace);
-    if (orig_total_slots > total_slots) {
-        objspace->heap_pages.allocatable_slots += orig_total_slots - total_slots;
-    }
-
-#if defined(HAVE_MALLOC_TRIM) && !defined(RUBY_ALTERNATIVE_MALLOC_HEADER)
-    malloc_trim(0);
-#endif
-}
-
-static int
-gc_is_moveable_obj(rb_objspace_t *objspace, VALUE obj)
-{
-    GC_ASSERT(!SPECIAL_CONST_P(obj));
-
-    switch (BUILTIN_TYPE(obj)) {
-      case T_NONE:
-      case T_MOVED:
-      case T_ZOMBIE:
-        return FALSE;
-      case T_SYMBOL:
-        // TODO: restore original behavior
-        // if (RSYMBOL(obj)->id & ~ID_SCOPE_MASK) {
-        //     return FALSE;
-        // }
-        return false;
-        /* fall through */
-      case T_STRING:
-      case T_OBJECT:
-      case T_FLOAT:
-      case T_IMEMO:
-      case T_ARRAY:
-      case T_BIGNUM:
-      case T_ICLASS:
-      case T_MODULE:
-      case T_REGEXP:
-      case T_DATA:
-      case T_MATCH:
-      case T_STRUCT:
-      case T_HASH:
-      case T_FILE:
-      case T_COMPLEX:
-      case T_RATIONAL:
-      case T_NODE:
-      case T_CLASS:
-        if (FL_TEST(obj, FL_FINALIZE)) {
-            /* The finalizer table is a numtable. It looks up objects by address.
-             * We can't mark the keys in the finalizer table because that would
-             * prevent the objects from being collected.  This check prevents
-             * objects that are keys in the finalizer table from being moved
-             * without directly pinning them. */
-            GC_ASSERT(st_is_member(finalizer_table, obj));
-
-            return FALSE;
-        }
-        GC_ASSERT(RVALUE_MARKED(objspace, obj));
-        GC_ASSERT(!RVALUE_PINNED(objspace, obj));
-
-        return TRUE;
-
-      default:
-        rb_bug("gc_is_moveable_obj: unreachable (%d)", (int)BUILTIN_TYPE(obj));
-        break;
-    }
-
-    return FALSE;
-}
-
-void rb_mv_generic_ivar(VALUE src, VALUE dst);
-
-static VALUE
-gc_move(rb_objspace_t *objspace, VALUE src, VALUE dest, size_t src_slot_size, size_t slot_size)
-{
-    int marked;
-    int wb_unprotected;
-    int uncollectible;
-    int age;
-
-    gc_report(4, objspace, "Moving object: %p -> %p\n", (void *)src, (void *)dest);
-
-    GC_ASSERT(BUILTIN_TYPE(src) != T_NONE);
-    GC_ASSERT(!MARKED_IN_BITMAP(GET_HEAP_MARK_BITS(dest), dest));
-
-    GC_ASSERT(!RVALUE_MARKING(objspace, src));
-
-    /* Save off bits for current object. */
-    marked = RVALUE_MARKED(objspace, src);
-    wb_unprotected = RVALUE_WB_UNPROTECTED(objspace, src);
-    uncollectible = RVALUE_UNCOLLECTIBLE(objspace, src);
-    bool remembered = RVALUE_REMEMBERED(objspace, src);
-    age = RVALUE_AGE_GET(src);
-
-    /* Clear bits for eventual T_MOVED */
-    CLEAR_IN_BITMAP(GET_HEAP_MARK_BITS(src), src);
-    CLEAR_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(src), src);
-    CLEAR_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(src), src);
-    CLEAR_IN_BITMAP(GET_HEAP_PAGE(src)->remembered_bits, src);
-
-    if (FL_TEST(src, FL_EXIVAR)) {
-        /* Resizing the st table could cause a malloc */
-        DURING_GC_COULD_MALLOC_REGION_START();
-        {
-            rb_mv_generic_ivar(src, dest);
-        }
-        DURING_GC_COULD_MALLOC_REGION_END();
-    }
-
-    if (FL_TEST(src, FL_SEEN_OBJ_ID)) {
-        /* If the source object's object_id has been seen, we need to update
-         * the object to object id mapping. */
-        st_data_t srcid = (st_data_t)src, id;
-
-        gc_report(4, objspace, "Moving object with seen id: %p -> %p\n", (void *)src, (void *)dest);
-        /* Resizing the st table could cause a malloc */
-        DURING_GC_COULD_MALLOC_REGION_START();
-        {
-            if (!st_delete(objspace->obj_to_id_tbl, &srcid, &id)) {
-                rb_bug("gc_move: object ID seen, but not in mapping table: %s", rb_obj_info((VALUE)src));
-            }
-
-            st_insert(objspace->obj_to_id_tbl, (st_data_t)dest, id);
-        }
-        DURING_GC_COULD_MALLOC_REGION_END();
-    }
-    else {
-        GC_ASSERT(!st_lookup(objspace->obj_to_id_tbl, (st_data_t)src, NULL));
-    }
-
-    /* Move the object */
-    memcpy((void *)dest, (void *)src, MIN(src_slot_size, slot_size));
-
-    if (RVALUE_OVERHEAD > 0) {
-        void *dest_overhead = (void *)(((uintptr_t)dest) + slot_size - RVALUE_OVERHEAD);
-        void *src_overhead = (void *)(((uintptr_t)src) + src_slot_size - RVALUE_OVERHEAD);
-
-        memcpy(dest_overhead, src_overhead, RVALUE_OVERHEAD);
-    }
-
-    memset((void *)src, 0, src_slot_size);
-    RVALUE_AGE_RESET(src);
-
-    /* Set bits for object in new location */
-    if (remembered) {
-        MARK_IN_BITMAP(GET_HEAP_PAGE(dest)->remembered_bits, dest);
-    }
-    else {
-        CLEAR_IN_BITMAP(GET_HEAP_PAGE(dest)->remembered_bits, dest);
-    }
-
-    if (marked) {
-        MARK_IN_BITMAP(GET_HEAP_MARK_BITS(dest), dest);
-    }
-    else {
-        CLEAR_IN_BITMAP(GET_HEAP_MARK_BITS(dest), dest);
-    }
-
-    if (wb_unprotected) {
-        MARK_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(dest), dest);
-    }
-    else {
-        CLEAR_IN_BITMAP(GET_HEAP_WB_UNPROTECTED_BITS(dest), dest);
-    }
-
-    if (uncollectible) {
-        MARK_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(dest), dest);
-    }
-    else {
-        CLEAR_IN_BITMAP(GET_HEAP_UNCOLLECTIBLE_BITS(dest), dest);
-    }
-
-    RVALUE_AGE_SET(dest, age);
-    /* Assign forwarding address */
-    RMOVED(src)->flags = T_MOVED;
-    RMOVED(src)->dummy = Qundef;
-    RMOVED(src)->destination = dest;
-    GC_ASSERT(BUILTIN_TYPE(dest) != T_NONE);
-
-    GET_HEAP_PAGE(src)->heap->total_freed_objects++;
-    GET_HEAP_PAGE(dest)->heap->total_allocated_objects++;
-
-    return src;
-}
-
-#if GC_CAN_COMPILE_COMPACTION
-static int
-compare_pinned_slots(const void *left, const void *right, void *dummy)
-{
-    struct heap_page *left_page;
-    struct heap_page *right_page;
-
-    left_page = *(struct heap_page * const *)left;
-    right_page = *(struct heap_page * const *)right;
-
-    return left_page->pinned_slots - right_page->pinned_slots;
-}
-
-static int
-compare_free_slots(const void *left, const void *right, void *dummy)
-{
-    struct heap_page *left_page;
-    struct heap_page *right_page;
-
-    left_page = *(struct heap_page * const *)left;
-    right_page = *(struct heap_page * const *)right;
-
-    return left_page->free_slots - right_page->free_slots;
-}
-
-static void
-gc_sort_heap_by_compare_func(rb_objspace_t *objspace, gc_compact_compare_func compare_func)
-{
-    for (int j = 0; j < HEAP_COUNT; j++) {
-        rb_heap_t *heap = &heaps[j];
-
-        size_t total_pages = heap->total_pages;
-        size_t size = rb_size_mul_or_raise(total_pages, sizeof(struct heap_page *), rb_eRuntimeError);
-        struct heap_page *page = 0, **page_list = malloc(size);
-        size_t i = 0;
-
-        heap->free_pages = NULL;
-        ccan_list_for_each(&heap->pages, page, page_node) {
-            page_list[i++] = page;
-            GC_ASSERT(page);
-        }
-
-        GC_ASSERT((size_t)i == total_pages);
-
-        /* Sort the heap so "filled pages" are first. `heap_add_page` adds to the
-         * head of the list, so empty pages will end up at the start of the heap */
-        ruby_qsort(page_list, total_pages, sizeof(struct heap_page *), compare_func, NULL);
-
-        /* Reset the eden heap */
-        ccan_list_head_init(&heap->pages);
-
-        for (i = 0; i < total_pages; i++) {
-            ccan_list_add(&heap->pages, &page_list[i]->page_node);
-            if (page_list[i]->free_slots != 0) {
-                heap_add_freepage(heap, page_list[i]);
-            }
-        }
-
-        free(page_list);
-    }
-}
-#endif
-
-bool
-rb_gc_impl_object_moved_p(void *objspace_ptr, VALUE obj)
-{
-    return gc_object_moved_p(objspace_ptr, obj);
-}
-
-static int
-gc_ref_update(void *vstart, void *vend, size_t stride, rb_objspace_t *objspace, struct heap_page *page)
-{
-    VALUE v = (VALUE)vstart;
-
-    page->flags.has_uncollectible_wb_unprotected_objects = FALSE;
-    page->flags.has_remembered_objects = FALSE;
-
-    /* For each object on the page */
-    for (; v != (VALUE)vend; v += stride) {
-        asan_unpoisoning_object(v) {
-            switch (BUILTIN_TYPE(v)) {
-              case T_NONE:
-              case T_MOVED:
-              case T_ZOMBIE:
-                break;
-              default:
-                if (RVALUE_WB_UNPROTECTED(objspace, v)) {
-                    page->flags.has_uncollectible_wb_unprotected_objects = TRUE;
-                }
-                if (RVALUE_REMEMBERED(objspace, v)) {
-                    page->flags.has_remembered_objects = TRUE;
-                }
-                if (page->flags.before_sweep) {
-                    if (RVALUE_MARKED(objspace, v)) {
-                        rb_gc_update_object_references(objspace, v);
-                    }
-                }
-                else {
-                    rb_gc_update_object_references(objspace, v);
-                }
-            }
-        }
-    }
-
-    return 0;
-}
-
-static void
-gc_update_references(rb_objspace_t *objspace)
-{
-    objspace->flags.during_reference_updating = true;
-
-    struct heap_page *page = NULL;
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        bool should_set_mark_bits = TRUE;
-        rb_heap_t *heap = &heaps[i];
-
-        ccan_list_for_each(&heap->pages, page, page_node) {
-            uintptr_t start = (uintptr_t)page->start;
-            uintptr_t end = start + (page->total_slots * heap->slot_size);
-
-            gc_ref_update((void *)start, (void *)end, heap->slot_size, objspace, page);
-            if (page == heap->sweeping_page) {
-                should_set_mark_bits = FALSE;
-            }
-            if (should_set_mark_bits) {
-                gc_setup_mark_bits(page);
-            }
-        }
-    }
-    gc_ref_update_table_values_only(objspace->obj_to_id_tbl);
-    gc_update_table_refs(objspace->id_to_obj_tbl);
-    gc_update_table_refs(finalizer_table);
-
-    rb_gc_update_vm_references((void *)objspace);
-
-    objspace->flags.during_reference_updating = false;
-}
-
-#if GC_CAN_COMPILE_COMPACTION
-static void
-root_obj_check_moved_i(const char *category, VALUE obj, void *data)
-{
-    rb_objspace_t *objspace = data;
-
-    if (gc_object_moved_p(objspace, obj)) {
-        rb_bug("ROOT %s points to MOVED: %p -> %s", category, (void *)obj, rb_obj_info(rb_gc_impl_location(objspace, obj)));
-    }
-}
-
-static void
-reachable_object_check_moved_i(VALUE ref, void *data)
-{
-    VALUE parent = (VALUE)data;
-    if (gc_object_moved_p(rb_gc_get_objspace(), ref)) {
-        rb_bug("Object %s points to MOVED: %p -> %s", rb_obj_info(parent), (void *)ref, rb_obj_info(rb_gc_impl_location(rb_gc_get_objspace(), ref)));
-    }
-}
-
-static int
-heap_check_moved_i(void *vstart, void *vend, size_t stride, void *data)
-{
-    rb_objspace_t *objspace = data;
-
-    VALUE v = (VALUE)vstart;
-    for (; v != (VALUE)vend; v += stride) {
-        if (gc_object_moved_p(objspace, v)) {
-            /* Moved object still on the heap, something may have a reference. */
-        }
-        else {
-            asan_unpoisoning_object(v) {
-                switch (BUILTIN_TYPE(v)) {
-                  case T_NONE:
-                  case T_ZOMBIE:
-                    break;
-                  default:
-                    if (!rb_gc_impl_garbage_object_p(objspace, v)) {
-                        rb_objspace_reachable_objects_from(v, reachable_object_check_moved_i, (void *)v);
-                    }
-                }
-            }
-        }
-    }
-
-    return 0;
-}
-#endif
-
-bool
-rb_gc_impl_during_gc_p(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    return during_gc;
-}
-
-#if RGENGC_PROFILE >= 2
-
-static const char*
-type_name(int type, VALUE obj)
-{
-    switch ((enum ruby_value_type)type) {
-      case RUBY_T_NONE:     return "T_NONE";
-      case RUBY_T_OBJECT:   return "T_OBJECT";
-      case RUBY_T_CLASS:    return "T_CLASS";
-      case RUBY_T_MODULE:   return "T_MODULE";
-      case RUBY_T_FLOAT:    return "T_FLOAT";
-      case RUBY_T_STRING:   return "T_STRING";
-      case RUBY_T_REGEXP:   return "T_REGEXP";
-      case RUBY_T_ARRAY:    return "T_ARRAY";
-      case RUBY_T_HASH:     return "T_HASH";
-      case RUBY_T_STRUCT:   return "T_STRUCT";
-      case RUBY_T_BIGNUM:   return "T_BIGNUM";
-      case RUBY_T_FILE:     return "T_FILE";
-      case RUBY_T_DATA:     return "T_DATA";
-      case RUBY_T_MATCH:    return "T_MATCH";
-      case RUBY_T_COMPLEX:  return "T_COMPLEX";
-      case RUBY_T_RATIONAL: return "T_RATIONAL";
-      case RUBY_T_NIL:      return "T_NIL";
-      case RUBY_T_TRUE:     return "T_TRUE";
-      case RUBY_T_FALSE:    return "T_FALSE";
-      case RUBY_T_SYMBOL:   return "T_SYMBOL";
-      case RUBY_T_FIXNUM:   return "T_FIXNUM";
-      case RUBY_T_UNDEF:    return "T_UNDEF";
-      case RUBY_T_IMEMO:    return "T_IMEMO";
-      case RUBY_T_NODE:     return "T_NODE";
-      case RUBY_T_ICLASS:   return "T_ICLASS";
-      case RUBY_T_ZOMBIE:   return "T_ZOMBIE";
-      case RUBY_T_MOVED:    return "T_MOVED";
-      default:              return "unknown";
-    }
-}
-
-static void
-gc_count_add_each_types(VALUE hash, const char *name, const size_t *types)
-{
-    VALUE result = rb_hash_new_with_size(T_MASK);
-    int i;
-    for (i=0; i<T_MASK; i++) {
-        const char *type = type_name(i, 0);
-        rb_hash_aset(result, ID2SYM(rb_intern(type)), SIZET2NUM(types[i]));
-    }
-    rb_hash_aset(hash, ID2SYM(rb_intern(name)), result);
-}
-#endif
-
-size_t
-rb_gc_impl_gc_count(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    return objspace->profile.count;
-}
-
-static VALUE
-gc_info_decode(rb_objspace_t *objspace, const VALUE hash_or_key, const unsigned int orig_flags)
-{
-    static VALUE sym_major_by = Qnil, sym_gc_by, sym_immediate_sweep, sym_have_finalizer, sym_state, sym_need_major_by;
-    static VALUE sym_nofree, sym_oldgen, sym_shady, sym_force, sym_stress;
-#if RGENGC_ESTIMATE_OLDMALLOC
-    static VALUE sym_oldmalloc;
-#endif
-    static VALUE sym_newobj, sym_malloc, sym_method, sym_capi;
-    static VALUE sym_none, sym_marking, sym_sweeping;
-    static VALUE sym_weak_references_count, sym_retained_weak_references_count;
-    VALUE hash = Qnil, key = Qnil;
-    VALUE major_by, need_major_by;
-    unsigned int flags = orig_flags ? orig_flags : objspace->profile.latest_gc_info;
-
-    if (SYMBOL_P(hash_or_key)) {
-        key = hash_or_key;
-    }
-    else if (RB_TYPE_P(hash_or_key, T_HASH)) {
-        hash = hash_or_key;
-    }
-    else {
-        rb_bug("gc_info_decode: non-hash or symbol given");
-    }
-
-    if (NIL_P(sym_major_by)) {
-#define S(s) sym_##s = ID2SYM(rb_intern_const(#s))
-        S(major_by);
-        S(gc_by);
-        S(immediate_sweep);
-        S(have_finalizer);
-        S(state);
-        S(need_major_by);
-
-        S(stress);
-        S(nofree);
-        S(oldgen);
-        S(shady);
-        S(force);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        S(oldmalloc);
-#endif
-        S(newobj);
-        S(malloc);
-        S(method);
-        S(capi);
-
-        S(none);
-        S(marking);
-        S(sweeping);
-
-        S(weak_references_count);
-        S(retained_weak_references_count);
-#undef S
-    }
-
-#define SET(name, attr) \
-    if (key == sym_##name) \
-        return (attr); \
-    else if (hash != Qnil) \
-        rb_hash_aset(hash, sym_##name, (attr));
-
-    major_by =
-      (flags & GPR_FLAG_MAJOR_BY_NOFREE) ? sym_nofree :
-      (flags & GPR_FLAG_MAJOR_BY_OLDGEN) ? sym_oldgen :
-      (flags & GPR_FLAG_MAJOR_BY_SHADY)  ? sym_shady :
-      (flags & GPR_FLAG_MAJOR_BY_FORCE)  ? sym_force :
-#if RGENGC_ESTIMATE_OLDMALLOC
-      (flags & GPR_FLAG_MAJOR_BY_OLDMALLOC) ? sym_oldmalloc :
-#endif
-      Qnil;
-    SET(major_by, major_by);
-
-    if (orig_flags == 0) { /* set need_major_by only if flags not set explicitly */
-        unsigned int need_major_flags = gc_needs_major_flags;
-        need_major_by =
-            (need_major_flags & GPR_FLAG_MAJOR_BY_NOFREE) ? sym_nofree :
-            (need_major_flags & GPR_FLAG_MAJOR_BY_OLDGEN) ? sym_oldgen :
-            (need_major_flags & GPR_FLAG_MAJOR_BY_SHADY)  ? sym_shady :
-            (need_major_flags & GPR_FLAG_MAJOR_BY_FORCE)  ? sym_force :
-#if RGENGC_ESTIMATE_OLDMALLOC
-            (need_major_flags & GPR_FLAG_MAJOR_BY_OLDMALLOC) ? sym_oldmalloc :
-#endif
-            Qnil;
-        SET(need_major_by, need_major_by);
-    }
-
-    SET(gc_by,
-        (flags & GPR_FLAG_NEWOBJ) ? sym_newobj :
-        (flags & GPR_FLAG_MALLOC) ? sym_malloc :
-        (flags & GPR_FLAG_METHOD) ? sym_method :
-        (flags & GPR_FLAG_CAPI)   ? sym_capi :
-        (flags & GPR_FLAG_STRESS) ? sym_stress :
-        Qnil
-    );
-
-    SET(have_finalizer, (flags & GPR_FLAG_HAVE_FINALIZE) ? Qtrue : Qfalse);
-    SET(immediate_sweep, (flags & GPR_FLAG_IMMEDIATE_SWEEP) ? Qtrue : Qfalse);
-
-    if (orig_flags == 0) {
-        SET(state, gc_mode(objspace) == gc_mode_none ? sym_none :
-                   gc_mode(objspace) == gc_mode_marking ? sym_marking : sym_sweeping);
-    }
-
-    SET(weak_references_count, LONG2FIX(objspace->profile.weak_references_count));
-    SET(retained_weak_references_count, LONG2FIX(objspace->profile.retained_weak_references_count));
-#undef SET
-
-    if (!NIL_P(key)) {
-        // Matched key should return above
-        return Qundef;
-    }
-
-    return hash;
-}
-
-VALUE
-rb_gc_impl_latest_gc_info(void *objspace_ptr, VALUE key)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    return gc_info_decode(objspace, key, 0);
-}
-
-
-enum gc_stat_sym {
-    gc_stat_sym_count,
-    gc_stat_sym_time,
-    gc_stat_sym_marking_time,
-    gc_stat_sym_sweeping_time,
-    gc_stat_sym_heap_allocated_pages,
-    gc_stat_sym_heap_empty_pages,
-    gc_stat_sym_heap_allocatable_slots,
-    gc_stat_sym_heap_available_slots,
-    gc_stat_sym_heap_live_slots,
-    gc_stat_sym_heap_free_slots,
-    gc_stat_sym_heap_final_slots,
-    gc_stat_sym_heap_marked_slots,
-    gc_stat_sym_heap_eden_pages,
-    gc_stat_sym_total_allocated_pages,
-    gc_stat_sym_total_freed_pages,
-    gc_stat_sym_total_allocated_objects,
-    gc_stat_sym_total_freed_objects,
-    gc_stat_sym_malloc_increase_bytes,
-    gc_stat_sym_malloc_increase_bytes_limit,
-    gc_stat_sym_minor_gc_count,
-    gc_stat_sym_major_gc_count,
-    gc_stat_sym_compact_count,
-    gc_stat_sym_read_barrier_faults,
-    gc_stat_sym_total_moved_objects,
-    gc_stat_sym_remembered_wb_unprotected_objects,
-    gc_stat_sym_remembered_wb_unprotected_objects_limit,
-    gc_stat_sym_old_objects,
-    gc_stat_sym_old_objects_limit,
-#if RGENGC_ESTIMATE_OLDMALLOC
-    gc_stat_sym_oldmalloc_increase_bytes,
-    gc_stat_sym_oldmalloc_increase_bytes_limit,
-#endif
-    gc_stat_sym_weak_references_count,
-#if RGENGC_PROFILE
-    gc_stat_sym_total_generated_normal_object_count,
-    gc_stat_sym_total_generated_shady_object_count,
-    gc_stat_sym_total_shade_operation_count,
-    gc_stat_sym_total_promoted_count,
-    gc_stat_sym_total_remembered_normal_object_count,
-    gc_stat_sym_total_remembered_shady_object_count,
-#endif
-    gc_stat_sym_last
-};
-
-static VALUE gc_stat_symbols[gc_stat_sym_last];
-
-static void
-setup_gc_stat_symbols(void)
-{
-    if (gc_stat_symbols[0] == 0) {
-#define S(s) gc_stat_symbols[gc_stat_sym_##s] = ID2SYM(rb_intern_const(#s))
-        S(count);
-        S(time);
-        S(marking_time),
-        S(sweeping_time),
-        S(heap_allocated_pages);
-        S(heap_empty_pages);
-        S(heap_allocatable_slots);
-        S(heap_available_slots);
-        S(heap_live_slots);
-        S(heap_free_slots);
-        S(heap_final_slots);
-        S(heap_marked_slots);
-        S(heap_eden_pages);
-        S(total_allocated_pages);
-        S(total_freed_pages);
-        S(total_allocated_objects);
-        S(total_freed_objects);
-        S(malloc_increase_bytes);
-        S(malloc_increase_bytes_limit);
-        S(minor_gc_count);
-        S(major_gc_count);
-        S(compact_count);
-        S(read_barrier_faults);
-        S(total_moved_objects);
-        S(remembered_wb_unprotected_objects);
-        S(remembered_wb_unprotected_objects_limit);
-        S(old_objects);
-        S(old_objects_limit);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        S(oldmalloc_increase_bytes);
-        S(oldmalloc_increase_bytes_limit);
-#endif
-        S(weak_references_count);
-#if RGENGC_PROFILE
-        S(total_generated_normal_object_count);
-        S(total_generated_shady_object_count);
-        S(total_shade_operation_count);
-        S(total_promoted_count);
-        S(total_remembered_normal_object_count);
-        S(total_remembered_shady_object_count);
-#endif /* RGENGC_PROFILE */
-#undef S
-    }
-}
-
-static uint64_t
-ns_to_ms(uint64_t ns)
-{
-    return ns / (1000 * 1000);
-}
-
-VALUE
-rb_gc_impl_stat(void *objspace_ptr, VALUE hash_or_sym)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    VALUE hash = Qnil, key = Qnil;
-
-    setup_gc_stat_symbols();
-
-    if (RB_TYPE_P(hash_or_sym, T_HASH)) {
-        hash = hash_or_sym;
-    }
-    else if (SYMBOL_P(hash_or_sym)) {
-        key = hash_or_sym;
-    }
-    else {
-        rb_bug("non-hash or symbol given");
-    }
-
-#define SET(name, attr) \
-    if (key == gc_stat_symbols[gc_stat_sym_##name]) \
-        return SIZET2NUM(attr); \
-    else if (hash != Qnil) \
-        rb_hash_aset(hash, gc_stat_symbols[gc_stat_sym_##name], SIZET2NUM(attr));
-
-    SET(count, objspace->profile.count);
-    SET(time, (size_t)ns_to_ms(objspace->profile.marking_time_ns + objspace->profile.sweeping_time_ns)); // TODO: UINT64T2NUM
-    SET(marking_time, (size_t)ns_to_ms(objspace->profile.marking_time_ns));
-    SET(sweeping_time, (size_t)ns_to_ms(objspace->profile.sweeping_time_ns));
-
-    /* implementation dependent counters */
-    SET(heap_allocated_pages, rb_darray_size(objspace->heap_pages.sorted));
-    SET(heap_empty_pages, objspace->empty_pages_count)
-    SET(heap_allocatable_slots, objspace->heap_pages.allocatable_slots);
-    SET(heap_available_slots, objspace_available_slots(objspace));
-    SET(heap_live_slots, objspace_live_slots(objspace));
-    SET(heap_free_slots, objspace_free_slots(objspace));
-    SET(heap_final_slots, total_final_slots_count(objspace));
-    SET(heap_marked_slots, objspace->marked_slots);
-    SET(heap_eden_pages, heap_eden_total_pages(objspace));
-    SET(total_allocated_pages, objspace->heap_pages.allocated_pages);
-    SET(total_freed_pages, objspace->heap_pages.freed_pages);
-    SET(total_allocated_objects, total_allocated_objects(objspace));
-    SET(total_freed_objects, total_freed_objects(objspace));
-    SET(malloc_increase_bytes, malloc_increase);
-    SET(malloc_increase_bytes_limit, malloc_limit);
-    SET(minor_gc_count, objspace->profile.minor_gc_count);
-    SET(major_gc_count, objspace->profile.major_gc_count);
-    SET(compact_count, objspace->profile.compact_count);
-    SET(read_barrier_faults, objspace->profile.read_barrier_faults);
-    SET(total_moved_objects, objspace->rcompactor.total_moved);
-    SET(remembered_wb_unprotected_objects, objspace->rgengc.uncollectible_wb_unprotected_objects);
-    SET(remembered_wb_unprotected_objects_limit, objspace->rgengc.uncollectible_wb_unprotected_objects_limit);
-    SET(old_objects, objspace->rgengc.old_objects);
-    SET(old_objects_limit, objspace->rgengc.old_objects_limit);
-#if RGENGC_ESTIMATE_OLDMALLOC
-    SET(oldmalloc_increase_bytes, objspace->rgengc.oldmalloc_increase);
-    SET(oldmalloc_increase_bytes_limit, objspace->rgengc.oldmalloc_increase_limit);
-#endif
-
-#if RGENGC_PROFILE
-    SET(total_generated_normal_object_count, objspace->profile.total_generated_normal_object_count);
-    SET(total_generated_shady_object_count, objspace->profile.total_generated_shady_object_count);
-    SET(total_shade_operation_count, objspace->profile.total_shade_operation_count);
-    SET(total_promoted_count, objspace->profile.total_promoted_count);
-    SET(total_remembered_normal_object_count, objspace->profile.total_remembered_normal_object_count);
-    SET(total_remembered_shady_object_count, objspace->profile.total_remembered_shady_object_count);
-#endif /* RGENGC_PROFILE */
-#undef SET
-
-    if (!NIL_P(key)) {
-        // Matched key should return above
-        return Qundef;
-    }
-
-#if defined(RGENGC_PROFILE) && RGENGC_PROFILE >= 2
-    if (hash != Qnil) {
-        gc_count_add_each_types(hash, "generated_normal_object_count_types", objspace->profile.generated_normal_object_count_types);
-        gc_count_add_each_types(hash, "generated_shady_object_count_types", objspace->profile.generated_shady_object_count_types);
-        gc_count_add_each_types(hash, "shade_operation_count_types", objspace->profile.shade_operation_count_types);
-        gc_count_add_each_types(hash, "promoted_types", objspace->profile.promoted_types);
-        gc_count_add_each_types(hash, "remembered_normal_object_count_types", objspace->profile.remembered_normal_object_count_types);
-        gc_count_add_each_types(hash, "remembered_shady_object_count_types", objspace->profile.remembered_shady_object_count_types);
-    }
-#endif
-
-    return hash;
-}
-
-enum gc_stat_heap_sym {
-    gc_stat_heap_sym_slot_size,
-    gc_stat_heap_sym_heap_eden_pages,
-    gc_stat_heap_sym_heap_eden_slots,
-    gc_stat_heap_sym_total_allocated_pages,
-    gc_stat_heap_sym_force_major_gc_count,
-    gc_stat_heap_sym_force_incremental_marking_finish_count,
-    gc_stat_heap_sym_total_allocated_objects,
-    gc_stat_heap_sym_total_freed_objects,
-    gc_stat_heap_sym_last
-};
-
-static VALUE gc_stat_heap_symbols[gc_stat_heap_sym_last];
-
-static void
-setup_gc_stat_heap_symbols(void)
-{
-    if (gc_stat_heap_symbols[0] == 0) {
-#define S(s) gc_stat_heap_symbols[gc_stat_heap_sym_##s] = ID2SYM(rb_intern_const(#s))
-        S(slot_size);
-        S(heap_eden_pages);
-        S(heap_eden_slots);
-        S(total_allocated_pages);
-        S(force_major_gc_count);
-        S(force_incremental_marking_finish_count);
-        S(total_allocated_objects);
-        S(total_freed_objects);
-#undef S
-    }
-}
-
-static VALUE
-stat_one_heap(rb_heap_t *heap, VALUE hash, VALUE key)
-{
-#define SET(name, attr) \
-    if (key == gc_stat_heap_symbols[gc_stat_heap_sym_##name]) \
-        return SIZET2NUM(attr); \
-    else if (hash != Qnil) \
-        rb_hash_aset(hash, gc_stat_heap_symbols[gc_stat_heap_sym_##name], SIZET2NUM(attr));
-
-    SET(slot_size, heap->slot_size);
-    SET(heap_eden_pages, heap->total_pages);
-    SET(heap_eden_slots, heap->total_slots);
-    SET(total_allocated_pages, heap->total_allocated_pages);
-    SET(force_major_gc_count, heap->force_major_gc_count);
-    SET(force_incremental_marking_finish_count, heap->force_incremental_marking_finish_count);
-    SET(total_allocated_objects, heap->total_allocated_objects);
-    SET(total_freed_objects, heap->total_freed_objects);
-#undef SET
-
-    if (!NIL_P(key)) {
-        // Matched key should return above
-        return Qundef;
-    }
-
-    return hash;
-}
-
-VALUE
-rb_gc_impl_stat_heap(void *objspace_ptr, VALUE heap_name, VALUE hash_or_sym)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    setup_gc_stat_heap_symbols();
-
-    if (NIL_P(heap_name)) {
-        if (!RB_TYPE_P(hash_or_sym, T_HASH)) {
-            rb_bug("non-hash given");
-        }
-
-        for (int i = 0; i < HEAP_COUNT; i++) {
-            VALUE hash = rb_hash_aref(hash_or_sym, INT2FIX(i));
-            if (NIL_P(hash)) {
-                hash = rb_hash_new();
-                rb_hash_aset(hash_or_sym, INT2FIX(i), hash);
-            }
-
-            stat_one_heap(&heaps[i], hash, Qnil);
-        }
-    }
-    else if (FIXNUM_P(heap_name)) {
-        int heap_idx = FIX2INT(heap_name);
-
-        if (heap_idx < 0 || heap_idx >= HEAP_COUNT) {
-            rb_raise(rb_eArgError, "size pool index out of range");
-        }
-
-        if (SYMBOL_P(hash_or_sym)) {
-            return stat_one_heap(&heaps[heap_idx], Qnil, hash_or_sym);
-        }
-        else if (RB_TYPE_P(hash_or_sym, T_HASH)) {
-            return stat_one_heap(&heaps[heap_idx], hash_or_sym, Qnil);
-        }
-        else {
-            rb_bug("non-hash or symbol given");
-        }
-    }
-    else {
-        rb_bug("heap_name must be nil or an Integer");
-    }
-
-    return hash_or_sym;
-}
-
-/* I could include internal.h for this, but doing so undefines some Array macros
- * necessary for initialising objects, and I don't want to include all the array
- * headers to get them back
- * TODO: Investigate why RARRAY_AREF gets undefined in internal.h
- */
-#ifndef RBOOL
-#define RBOOL(v) (v ? Qtrue : Qfalse)
-#endif
-
-VALUE
-rb_gc_impl_config_get(void *objspace_ptr)
-{
-#define sym(name) ID2SYM(rb_intern_const(name))
-    rb_objspace_t *objspace = objspace_ptr;
-    VALUE hash = rb_hash_new();
-
-    rb_hash_aset(hash, sym("rgengc_allow_full_mark"), RBOOL(gc_config_full_mark_val));
-
-    return hash;
-}
-
-static int
-gc_config_set_key(st_data_t key, st_data_t value, st_data_t data)
-{
-    rb_objspace_t *objspace = (rb_objspace_t *)data;
-    if (rb_sym2id(key) == rb_intern("rgengc_allow_full_mark")) {
-        gc_rest(objspace);
-        gc_config_full_mark_set(RTEST(value));
-    }
-    return ST_CONTINUE;
-}
-
-void
-rb_gc_impl_config_set(void *objspace_ptr, VALUE hash)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (!RB_TYPE_P(hash, T_HASH)) {
-        rb_raise(rb_eArgError, "expected keyword arguments");
-    }
-
-    rb_hash_stlike_foreach(hash, gc_config_set_key, (st_data_t)objspace);
-}
-
-VALUE
-rb_gc_impl_stress_get(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    return ruby_gc_stress_mode;
-}
-
-void
-rb_gc_impl_stress_set(void *objspace_ptr, VALUE flag)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    objspace->flags.gc_stressful = RTEST(flag);
-    objspace->gc_stress_mode = flag;
-}
-
-static int
-get_envparam_size(const char *name, size_t *default_value, size_t lower_bound)
-{
-    const char *ptr = getenv(name);
-    ssize_t val;
-
-    if (ptr != NULL && *ptr) {
-        size_t unit = 0;
-        char *end;
-#if SIZEOF_SIZE_T == SIZEOF_LONG_LONG
-        val = strtoll(ptr, &end, 0);
-#else
-        val = strtol(ptr, &end, 0);
-#endif
-        switch (*end) {
-          case 'k': case 'K':
-            unit = 1024;
-            ++end;
-            break;
-          case 'm': case 'M':
-            unit = 1024*1024;
-            ++end;
-            break;
-          case 'g': case 'G':
-            unit = 1024*1024*1024;
-            ++end;
-            break;
-        }
-        while (*end && isspace((unsigned char)*end)) end++;
-        if (*end) {
-            if (RTEST(ruby_verbose)) fprintf(stderr, "invalid string for %s: %s\n", name, ptr);
-            return 0;
-        }
-        if (unit > 0) {
-            if (val < -(ssize_t)(SIZE_MAX / 2 / unit) || (ssize_t)(SIZE_MAX / 2 / unit) < val) {
-                if (RTEST(ruby_verbose)) fprintf(stderr, "%s=%s is ignored because it overflows\n", name, ptr);
-                return 0;
-            }
-            val *= unit;
-        }
-        if (val > 0 && (size_t)val > lower_bound) {
-            if (RTEST(ruby_verbose)) {
-                fprintf(stderr, "%s=%"PRIdSIZE" (default value: %"PRIuSIZE")\n", name, val, *default_value);
-            }
-            *default_value = (size_t)val;
-            return 1;
-        }
-        else {
-            if (RTEST(ruby_verbose)) {
-                fprintf(stderr, "%s=%"PRIdSIZE" (default value: %"PRIuSIZE") is ignored because it must be greater than %"PRIuSIZE".\n",
-                        name, val, *default_value, lower_bound);
-            }
-            return 0;
-        }
-    }
-    return 0;
-}
-
-static int
-get_envparam_double(const char *name, double *default_value, double lower_bound, double upper_bound, int accept_zero)
-{
-    const char *ptr = getenv(name);
-    double val;
-
-    if (ptr != NULL && *ptr) {
-        char *end;
-        val = strtod(ptr, &end);
-        if (!*ptr || *end) {
-            if (RTEST(ruby_verbose)) fprintf(stderr, "invalid string for %s: %s\n", name, ptr);
-            return 0;
-        }
-
-        if (accept_zero && val == 0.0) {
-            goto accept;
-        }
-        else if (val <= lower_bound) {
-            if (RTEST(ruby_verbose)) {
-                fprintf(stderr, "%s=%f (default value: %f) is ignored because it must be greater than %f.\n",
-                        name, val, *default_value, lower_bound);
-            }
-        }
-        else if (upper_bound != 0.0 && /* ignore upper_bound if it is 0.0 */
-                 val > upper_bound) {
-            if (RTEST(ruby_verbose)) {
-                fprintf(stderr, "%s=%f (default value: %f) is ignored because it must be lower than %f.\n",
-                        name, val, *default_value, upper_bound);
-            }
-        }
-        else {
-            goto accept;
-        }
-    }
-    return 0;
-
-  accept:
-    if (RTEST(ruby_verbose)) fprintf(stderr, "%s=%f (default value: %f)\n", name, val, *default_value);
-    *default_value = val;
-    return 1;
-}
-
-/*
- * GC tuning environment variables
- *
- * * RUBY_GC_HEAP_FREE_SLOTS
- *   - Prepare at least this amount of slots after GC.
- *   - Allocate slots if there are not enough slots.
- * * RUBY_GC_HEAP_GROWTH_FACTOR (new from 2.1)
- *   - Allocate slots by this factor.
- *   - (next slots number) = (current slots number) * (this factor)
- * * RUBY_GC_HEAP_GROWTH_MAX_SLOTS (new from 2.1)
- *   - Allocation rate is limited to this number of slots.
- * * RUBY_GC_HEAP_FREE_SLOTS_MIN_RATIO (new from 2.4)
- *   - Allocate additional pages when the number of free slots is
- *     lower than the value (total_slots * (this ratio)).
- * * RUBY_GC_HEAP_FREE_SLOTS_GOAL_RATIO (new from 2.4)
- *   - Allocate slots to satisfy this formula:
- *       free_slots = total_slots * goal_ratio
- *   - In other words, prepare (total_slots * goal_ratio) free slots.
- *   - if this value is 0.0, then use RUBY_GC_HEAP_GROWTH_FACTOR directly.
- * * RUBY_GC_HEAP_FREE_SLOTS_MAX_RATIO (new from 2.4)
- *   - Allow to free pages when the number of free slots is
- *     greater than the value (total_slots * (this ratio)).
- * * RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR (new from 2.1.1)
- *   - Do full GC when the number of old objects is more than R * N
- *     where R is this factor and
- *           N is the number of old objects just after last full GC.
- *
- *  * obsolete
- *    * RUBY_FREE_MIN       -> RUBY_GC_HEAP_FREE_SLOTS (from 2.1)
- *    * RUBY_HEAP_MIN_SLOTS -> RUBY_GC_HEAP_INIT_SLOTS (from 2.1)
- *
- * * RUBY_GC_MALLOC_LIMIT
- * * RUBY_GC_MALLOC_LIMIT_MAX (new from 2.1)
- * * RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR (new from 2.1)
- *
- * * RUBY_GC_OLDMALLOC_LIMIT (new from 2.1)
- * * RUBY_GC_OLDMALLOC_LIMIT_MAX (new from 2.1)
- * * RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR (new from 2.1)
- */
-
-void
-rb_gc_impl_set_params(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    /* RUBY_GC_HEAP_FREE_SLOTS */
-    if (get_envparam_size("RUBY_GC_HEAP_FREE_SLOTS", &gc_params.heap_free_slots, 0)) {
-        /* ok */
-    }
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        char env_key[sizeof("RUBY_GC_HEAP_" "_INIT_SLOTS") + DECIMAL_SIZE_OF_BITS(sizeof(int) * CHAR_BIT)];
-        snprintf(env_key, sizeof(env_key), "RUBY_GC_HEAP_%d_INIT_SLOTS", i);
-
-        get_envparam_size(env_key, &gc_params.heap_init_slots[i], 0);
-    }
-
-    get_envparam_double("RUBY_GC_HEAP_GROWTH_FACTOR", &gc_params.growth_factor, 1.0, 0.0, FALSE);
-    get_envparam_size  ("RUBY_GC_HEAP_GROWTH_MAX_SLOTS", &gc_params.growth_max_slots, 0);
-    get_envparam_double("RUBY_GC_HEAP_FREE_SLOTS_MIN_RATIO", &gc_params.heap_free_slots_min_ratio,
-                        0.0, 1.0, FALSE);
-    get_envparam_double("RUBY_GC_HEAP_FREE_SLOTS_MAX_RATIO", &gc_params.heap_free_slots_max_ratio,
-                        gc_params.heap_free_slots_min_ratio, 1.0, FALSE);
-    get_envparam_double("RUBY_GC_HEAP_FREE_SLOTS_GOAL_RATIO", &gc_params.heap_free_slots_goal_ratio,
-                        gc_params.heap_free_slots_min_ratio, gc_params.heap_free_slots_max_ratio, TRUE);
-    get_envparam_double("RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR", &gc_params.oldobject_limit_factor, 0.0, 0.0, TRUE);
-    get_envparam_double("RUBY_GC_HEAP_REMEMBERED_WB_UNPROTECTED_OBJECTS_LIMIT_RATIO", &gc_params.uncollectible_wb_unprotected_objects_limit_ratio, 0.0, 0.0, TRUE);
-
-    if (get_envparam_size("RUBY_GC_MALLOC_LIMIT", &gc_params.malloc_limit_min, 0)) {
-        malloc_limit = gc_params.malloc_limit_min;
-    }
-    get_envparam_size  ("RUBY_GC_MALLOC_LIMIT_MAX", &gc_params.malloc_limit_max, 0);
-    if (!gc_params.malloc_limit_max) { /* ignore max-check if 0 */
-        gc_params.malloc_limit_max = SIZE_MAX;
-    }
-    get_envparam_double("RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR", &gc_params.malloc_limit_growth_factor, 1.0, 0.0, FALSE);
-
-#if RGENGC_ESTIMATE_OLDMALLOC
-    if (get_envparam_size("RUBY_GC_OLDMALLOC_LIMIT", &gc_params.oldmalloc_limit_min, 0)) {
-        objspace->rgengc.oldmalloc_increase_limit = gc_params.oldmalloc_limit_min;
-    }
-    get_envparam_size  ("RUBY_GC_OLDMALLOC_LIMIT_MAX", &gc_params.oldmalloc_limit_max, 0);
-    get_envparam_double("RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR", &gc_params.oldmalloc_limit_growth_factor, 1.0, 0.0, FALSE);
-#endif
-}
-
-static inline size_t
-objspace_malloc_size(rb_objspace_t *objspace, void *ptr, size_t hint)
-{
-#ifdef HAVE_MALLOC_USABLE_SIZE
-    return malloc_usable_size(ptr);
-#else
-    return hint;
-#endif
-}
-
-enum memop_type {
-    MEMOP_TYPE_MALLOC  = 0,
-    MEMOP_TYPE_FREE,
-    MEMOP_TYPE_REALLOC
-};
-
-static inline void
-atomic_sub_nounderflow(size_t *var, size_t sub)
-{
-    if (sub == 0) return;
-
-    while (1) {
-        size_t val = *var;
-        if (val < sub) sub = val;
-        if (RUBY_ATOMIC_SIZE_CAS(*var, val, val-sub) == val) break;
-    }
-}
-
-#define gc_stress_full_mark_after_malloc_p() \
-    (FIXNUM_P(ruby_gc_stress_mode) && (FIX2LONG(ruby_gc_stress_mode) & (1<<gc_stress_full_mark_after_malloc)))
-
-static void
-objspace_malloc_gc_stress(rb_objspace_t *objspace)
-{
-    if (ruby_gc_stressful && ruby_native_thread_p()) {
-        unsigned int reason = (GPR_FLAG_IMMEDIATE_MARK | GPR_FLAG_IMMEDIATE_SWEEP |
-                               GPR_FLAG_STRESS | GPR_FLAG_MALLOC);
-
-        if (gc_stress_full_mark_after_malloc_p()) {
-            reason |= GPR_FLAG_FULL_MARK;
-        }
-        garbage_collect_with_gvl(objspace, reason);
-    }
-}
-
-static inline bool
-objspace_malloc_increase_report(rb_objspace_t *objspace, void *mem, size_t new_size, size_t old_size, enum memop_type type)
-{
-    if (0) fprintf(stderr, "increase - ptr: %p, type: %s, new_size: %"PRIdSIZE", old_size: %"PRIdSIZE"\n",
-                   mem,
-                   type == MEMOP_TYPE_MALLOC  ? "malloc" :
-                   type == MEMOP_TYPE_FREE    ? "free  " :
-                   type == MEMOP_TYPE_REALLOC ? "realloc": "error",
-                   new_size, old_size);
-    return false;
-}
-
-static bool
-objspace_malloc_increase_body(rb_objspace_t *objspace, void *mem, size_t new_size, size_t old_size, enum memop_type type)
-{
-    if (new_size > old_size) {
-        RUBY_ATOMIC_SIZE_ADD(malloc_increase, new_size - old_size);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        RUBY_ATOMIC_SIZE_ADD(objspace->rgengc.oldmalloc_increase, new_size - old_size);
-#endif
-    }
-    else {
-        atomic_sub_nounderflow(&malloc_increase, old_size - new_size);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        atomic_sub_nounderflow(&objspace->rgengc.oldmalloc_increase, old_size - new_size);
-#endif
-    }
-
-    if (type == MEMOP_TYPE_MALLOC) {
-      retry:
-        if (malloc_increase > malloc_limit && ruby_native_thread_p() && !dont_gc_val()) {
-            if (ruby_thread_has_gvl_p() && is_lazy_sweeping(objspace)) {
-                gc_rest(objspace); /* gc_rest can reduce malloc_increase */
-                goto retry;
-            }
-            garbage_collect_with_gvl(objspace, GPR_FLAG_MALLOC);
-        }
-    }
-
-#if MALLOC_ALLOCATED_SIZE
-    if (new_size >= old_size) {
-        RUBY_ATOMIC_SIZE_ADD(objspace->malloc_params.allocated_size, new_size - old_size);
-    }
-    else {
-        size_t dec_size = old_size - new_size;
-        size_t allocated_size = objspace->malloc_params.allocated_size;
-
-#if MALLOC_ALLOCATED_SIZE_CHECK
-        if (allocated_size < dec_size) {
-            rb_bug("objspace_malloc_increase: underflow malloc_params.allocated_size.");
-        }
-#endif
-        atomic_sub_nounderflow(&objspace->malloc_params.allocated_size, dec_size);
-    }
-
-    switch (type) {
-      case MEMOP_TYPE_MALLOC:
-        RUBY_ATOMIC_SIZE_INC(objspace->malloc_params.allocations);
-        break;
-      case MEMOP_TYPE_FREE:
-        {
-            size_t allocations = objspace->malloc_params.allocations;
-            if (allocations > 0) {
-                atomic_sub_nounderflow(&objspace->malloc_params.allocations, 1);
-            }
-#if MALLOC_ALLOCATED_SIZE_CHECK
-            else {
-                GC_ASSERT(objspace->malloc_params.allocations > 0);
-            }
-#endif
-        }
-        break;
-      case MEMOP_TYPE_REALLOC: /* ignore */ break;
-    }
-#endif
-    return true;
-}
-
-#define objspace_malloc_increase(...) \
-    for (bool malloc_increase_done = objspace_malloc_increase_report(__VA_ARGS__); \
-         !malloc_increase_done; \
-         malloc_increase_done = objspace_malloc_increase_body(__VA_ARGS__))
-
-struct malloc_obj_info { /* 4 words */
-    size_t size;
-};
-
-static inline size_t
-objspace_malloc_prepare(rb_objspace_t *objspace, size_t size)
-{
-    if (size == 0) size = 1;
-
-#if CALC_EXACT_MALLOC_SIZE
-    size += sizeof(struct malloc_obj_info);
-#endif
-
-    return size;
-}
-
-static bool
-malloc_during_gc_p(rb_objspace_t *objspace)
-{
-    /* malloc is not allowed during GC when we're not using multiple ractors
-     * (since ractors can run while another thread is sweeping) and when we
-     * have the GVL (since if we don't have the GVL, we'll try to acquire the
-     * GVL which will block and ensure the other thread finishes GC). */
-    return during_gc && !dont_gc_val() && !rb_gc_multi_ractor_p() && ruby_thread_has_gvl_p();
-}
-
-static inline void *
-objspace_malloc_fixup(rb_objspace_t *objspace, void *mem, size_t size)
-{
-    size = objspace_malloc_size(objspace, mem, size);
-    objspace_malloc_increase(objspace, mem, size, 0, MEMOP_TYPE_MALLOC) {}
-
-#if CALC_EXACT_MALLOC_SIZE
-    {
-        struct malloc_obj_info *info = mem;
-        info->size = size;
-        mem = info + 1;
-    }
-#endif
-
-    return mem;
-}
-
-#if defined(__GNUC__) && RUBY_DEBUG
-#define RB_BUG_INSTEAD_OF_RB_MEMERROR 1
-#endif
-
-#ifndef RB_BUG_INSTEAD_OF_RB_MEMERROR
-# define RB_BUG_INSTEAD_OF_RB_MEMERROR 0
-#endif
-
-#define GC_MEMERROR(...) \
-    ((RB_BUG_INSTEAD_OF_RB_MEMERROR+0) ? rb_bug("" __VA_ARGS__) : rb_memerror())
-
-#define TRY_WITH_GC(siz, expr) do {                          \
-        const gc_profile_record_flag gpr =                   \
-            GPR_FLAG_FULL_MARK           |                   \
-            GPR_FLAG_IMMEDIATE_MARK      |                   \
-            GPR_FLAG_IMMEDIATE_SWEEP     |                   \
-            GPR_FLAG_MALLOC;                                 \
-        objspace_malloc_gc_stress(objspace);                 \
-                                                             \
-        if (RB_LIKELY((expr))) {                                \
-            /* Success on 1st try */                         \
-        }                                                    \
-        else if (!garbage_collect_with_gvl(objspace, gpr)) { \
-            /* @shyouhei thinks this doesn't happen */       \
-            GC_MEMERROR("TRY_WITH_GC: could not GC");        \
-        }                                                    \
-        else if ((expr)) {                                   \
-            /* Success on 2nd try */                         \
-        }                                                    \
-        else {                                               \
-            GC_MEMERROR("TRY_WITH_GC: could not allocate:"   \
-                        "%"PRIdSIZE" bytes for %s",          \
-                        siz, # expr);                        \
-        }                                                    \
-    } while (0)
-
-static void
-check_malloc_not_in_gc(rb_objspace_t *objspace, const char *msg)
-{
-    if (RB_UNLIKELY(malloc_during_gc_p(objspace))) {
-        dont_gc_on();
-        during_gc = false;
-        rb_bug("Cannot %s during GC", msg);
-    }
-}
-
-void
-rb_gc_impl_free(void *objspace_ptr, void *ptr, size_t old_size)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (!ptr) {
-        /*
-         * ISO/IEC 9899 says "If ptr is a null pointer, no action occurs" since
-         * its first version.  We would better follow.
-         */
-        return;
-    }
-#if CALC_EXACT_MALLOC_SIZE
-    struct malloc_obj_info *info = (struct malloc_obj_info *)ptr - 1;
-    ptr = info;
-    old_size = info->size;
-#endif
-    old_size = objspace_malloc_size(objspace, ptr, old_size);
-
-    objspace_malloc_increase(objspace, ptr, 0, old_size, MEMOP_TYPE_FREE) {
-        free(ptr);
-        ptr = NULL;
-        RB_DEBUG_COUNTER_INC(heap_xfree);
-    }
-}
-
-void *
-rb_gc_impl_malloc(void *objspace_ptr, size_t size)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-    check_malloc_not_in_gc(objspace, "malloc");
-
-    void *mem;
-
-    size = objspace_malloc_prepare(objspace, size);
-    TRY_WITH_GC(size, mem = malloc(size));
-    RB_DEBUG_COUNTER_INC(heap_xmalloc);
-    return objspace_malloc_fixup(objspace, mem, size);
-}
-
-void *
-rb_gc_impl_calloc(void *objspace_ptr, size_t size)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (RB_UNLIKELY(malloc_during_gc_p(objspace))) {
-        rb_warn("calloc during GC detected, this could cause crashes if it triggers another GC");
-#if RGENGC_CHECK_MODE || RUBY_DEBUG
-        rb_bug("Cannot calloc during GC");
-#endif
-    }
-
-    void *mem;
-
-    size = objspace_malloc_prepare(objspace, size);
-    TRY_WITH_GC(size, mem = calloc1(size));
-    return objspace_malloc_fixup(objspace, mem, size);
-}
-
-void *
-rb_gc_impl_realloc(void *objspace_ptr, void *ptr, size_t new_size, size_t old_size)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    check_malloc_not_in_gc(objspace, "realloc");
-
-    void *mem;
-
-    if (!ptr) return rb_gc_impl_malloc(objspace, new_size);
-
-    /*
-     * The behavior of realloc(ptr, 0) is implementation defined.
-     * Therefore we don't use realloc(ptr, 0) for portability reason.
-     * see http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_400.htm
-     */
-    if (new_size == 0) {
-        if ((mem = rb_gc_impl_malloc(objspace, 0)) != NULL) {
-            /*
-             * - OpenBSD's malloc(3) man page says that when 0 is passed, it
-             *   returns a non-NULL pointer to an access-protected memory page.
-             *   The returned pointer cannot be read / written at all, but
-             *   still be a valid argument of free().
-             *
-             *   https://man.openbsd.org/malloc.3
-             *
-             * - Linux's malloc(3) man page says that it _might_ perhaps return
-             *   a non-NULL pointer when its argument is 0.  That return value
-             *   is safe (and is expected) to be passed to free().
-             *
-             *   https://man7.org/linux/man-pages/man3/malloc.3.html
-             *
-             * - As I read the implementation jemalloc's malloc() returns fully
-             *   normal 16 bytes memory region when its argument is 0.
-             *
-             * - As I read the implementation musl libc's malloc() returns
-             *   fully normal 32 bytes memory region when its argument is 0.
-             *
-             * - Other malloc implementations can also return non-NULL.
-             */
-            rb_gc_impl_free(objspace, ptr, old_size);
-            return mem;
-        }
-        else {
-            /*
-             * It is dangerous to return NULL here, because that could lead to
-             * RCE.  Fallback to 1 byte instead of zero.
-             *
-             * https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-11932
-             */
-            new_size = 1;
-        }
-    }
-
-#if CALC_EXACT_MALLOC_SIZE
-    {
-        struct malloc_obj_info *info = (struct malloc_obj_info *)ptr - 1;
-        new_size += sizeof(struct malloc_obj_info);
-        ptr = info;
-        old_size = info->size;
-    }
-#endif
-
-    old_size = objspace_malloc_size(objspace, ptr, old_size);
-    TRY_WITH_GC(new_size, mem = RB_GNUC_EXTENSION_BLOCK(realloc(ptr, new_size)));
-    new_size = objspace_malloc_size(objspace, mem, new_size);
-
-#if CALC_EXACT_MALLOC_SIZE
-    {
-        struct malloc_obj_info *info = mem;
-        info->size = new_size;
-        mem = info + 1;
-    }
-#endif
-
-    objspace_malloc_increase(objspace, mem, new_size, old_size, MEMOP_TYPE_REALLOC);
-
-    RB_DEBUG_COUNTER_INC(heap_xrealloc);
-    return mem;
-}
-
-void
-rb_gc_impl_adjust_memory_usage(void *objspace_ptr, ssize_t diff)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (diff > 0) {
-        objspace_malloc_increase(objspace, 0, diff, 0, MEMOP_TYPE_REALLOC);
-    }
-    else if (diff < 0) {
-        objspace_malloc_increase(objspace, 0, 0, -diff, MEMOP_TYPE_REALLOC);
-    }
-}
-
-// TODO: move GC profiler stuff back into gc.c
-/*
-  ------------------------------ GC profiler ------------------------------
-*/
-
-#define GC_PROFILE_RECORD_DEFAULT_SIZE 100
-
-static bool
-current_process_time(struct timespec *ts)
-{
-#if defined(HAVE_CLOCK_GETTIME) && defined(CLOCK_PROCESS_CPUTIME_ID)
-    {
-        static int try_clock_gettime = 1;
-        if (try_clock_gettime && clock_gettime(CLOCK_PROCESS_CPUTIME_ID, ts) == 0) {
-            return true;
-        }
-        else {
-            try_clock_gettime = 0;
-        }
-    }
-#endif
-
-#ifdef RUSAGE_SELF
-    {
-        struct rusage usage;
-        struct timeval time;
-        if (getrusage(RUSAGE_SELF, &usage) == 0) {
-            time = usage.ru_utime;
-            ts->tv_sec = time.tv_sec;
-            ts->tv_nsec = (int32_t)time.tv_usec * 1000;
-            return true;
-        }
-    }
-#endif
-
-#ifdef _WIN32
-    {
-        FILETIME creation_time, exit_time, kernel_time, user_time;
-        ULARGE_INTEGER ui;
-
-        if (GetProcessTimes(GetCurrentProcess(),
-                            &creation_time, &exit_time, &kernel_time, &user_time) != 0) {
-            memcpy(&ui, &user_time, sizeof(FILETIME));
-#define PER100NSEC (uint64_t)(1000 * 1000 * 10)
-            ts->tv_nsec = (long)(ui.QuadPart % PER100NSEC);
-            ts->tv_sec  = (time_t)(ui.QuadPart / PER100NSEC);
-            return true;
-        }
-    }
-#endif
-
-    return false;
-}
-
-static double
-getrusage_time(void)
-{
-    struct timespec ts;
-    if (current_process_time(&ts)) {
-        return ts.tv_sec + ts.tv_nsec * 1e-9;
-    }
-    else {
-        return 0.0;
-    }
-}
-
-
-static inline void
-gc_prof_setup_new_record(rb_objspace_t *objspace, unsigned int reason)
-{
-    if (objspace->profile.run) {
-        size_t index = objspace->profile.next_index;
-        gc_profile_record *record;
-
-        /* create new record */
-        objspace->profile.next_index++;
-
-        if (!objspace->profile.records) {
-            objspace->profile.size = GC_PROFILE_RECORD_DEFAULT_SIZE;
-            objspace->profile.records = malloc(xmalloc2_size(sizeof(gc_profile_record), objspace->profile.size));
-        }
-        if (index >= objspace->profile.size) {
-            void *ptr;
-            objspace->profile.size += 1000;
-            ptr = realloc(objspace->profile.records, xmalloc2_size(sizeof(gc_profile_record), objspace->profile.size));
-            if (!ptr) rb_memerror();
-            objspace->profile.records = ptr;
-        }
-        if (!objspace->profile.records) {
-            rb_bug("gc_profile malloc or realloc miss");
-        }
-        record = objspace->profile.current_record = &objspace->profile.records[objspace->profile.next_index - 1];
-        MEMZERO(record, gc_profile_record, 1);
-
-        /* setup before-GC parameter */
-        record->flags = reason | (ruby_gc_stressful ? GPR_FLAG_STRESS : 0);
-#if MALLOC_ALLOCATED_SIZE
-        record->allocated_size = malloc_allocated_size;
-#endif
-#if GC_PROFILE_MORE_DETAIL && GC_PROFILE_DETAIL_MEMORY
-#ifdef RUSAGE_SELF
-        {
-            struct rusage usage;
-            if (getrusage(RUSAGE_SELF, &usage) == 0) {
-                record->maxrss = usage.ru_maxrss;
-                record->minflt = usage.ru_minflt;
-                record->majflt = usage.ru_majflt;
-            }
-        }
-#endif
-#endif
-    }
-}
-
-static inline void
-gc_prof_timer_start(rb_objspace_t *objspace)
-{
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-#if GC_PROFILE_MORE_DETAIL
-        record->prepare_time = objspace->profile.prepare_time;
-#endif
-        record->gc_time = 0;
-        record->gc_invoke_time = getrusage_time();
-    }
-}
-
-static double
-elapsed_time_from(double time)
-{
-    double now = getrusage_time();
-    if (now > time) {
-        return now - time;
-    }
-    else {
-        return 0;
-    }
-}
-
-static inline void
-gc_prof_timer_stop(rb_objspace_t *objspace)
-{
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->gc_time = elapsed_time_from(record->gc_invoke_time);
-        record->gc_invoke_time -= objspace->profile.invoke_time;
-    }
-}
-
-#ifdef BUILDING_SHARED_GC
-# define RUBY_DTRACE_GC_HOOK(name)
-#else
-# define RUBY_DTRACE_GC_HOOK(name) \
-    do {if (RUBY_DTRACE_GC_##name##_ENABLED()) RUBY_DTRACE_GC_##name();} while (0)
-#endif
-
-static inline void
-gc_prof_mark_timer_start(rb_objspace_t *objspace)
-{
-    RUBY_DTRACE_GC_HOOK(MARK_BEGIN);
-#if GC_PROFILE_MORE_DETAIL
-    if (gc_prof_enabled(objspace)) {
-        gc_prof_record(objspace)->gc_mark_time = getrusage_time();
-    }
-#endif
-}
-
-static inline void
-gc_prof_mark_timer_stop(rb_objspace_t *objspace)
-{
-    RUBY_DTRACE_GC_HOOK(MARK_END);
-#if GC_PROFILE_MORE_DETAIL
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->gc_mark_time = elapsed_time_from(record->gc_mark_time);
-    }
-#endif
-}
-
-static inline void
-gc_prof_sweep_timer_start(rb_objspace_t *objspace)
-{
-    RUBY_DTRACE_GC_HOOK(SWEEP_BEGIN);
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-
-        if (record->gc_time > 0 || GC_PROFILE_MORE_DETAIL) {
-            objspace->profile.gc_sweep_start_time = getrusage_time();
-        }
-    }
-}
-
-static inline void
-gc_prof_sweep_timer_stop(rb_objspace_t *objspace)
-{
-    RUBY_DTRACE_GC_HOOK(SWEEP_END);
-
-    if (gc_prof_enabled(objspace)) {
-        double sweep_time;
-        gc_profile_record *record = gc_prof_record(objspace);
-
-        if (record->gc_time > 0) {
-            sweep_time = elapsed_time_from(objspace->profile.gc_sweep_start_time);
-            /* need to accumulate GC time for lazy sweep after gc() */
-            record->gc_time += sweep_time;
-        }
-        else if (GC_PROFILE_MORE_DETAIL) {
-            sweep_time = elapsed_time_from(objspace->profile.gc_sweep_start_time);
-        }
-
-#if GC_PROFILE_MORE_DETAIL
-        record->gc_sweep_time += sweep_time;
-        if (heap_pages_deferred_final) record->flags |= GPR_FLAG_HAVE_FINALIZE;
-#endif
-        if (heap_pages_deferred_final) objspace->profile.latest_gc_info |= GPR_FLAG_HAVE_FINALIZE;
-    }
-}
-
-static inline void
-gc_prof_set_malloc_info(rb_objspace_t *objspace)
-{
-#if GC_PROFILE_MORE_DETAIL
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        record->allocate_increase = malloc_increase;
-        record->allocate_limit = malloc_limit;
-    }
-#endif
-}
-
-static inline void
-gc_prof_set_heap_info(rb_objspace_t *objspace)
-{
-    if (gc_prof_enabled(objspace)) {
-        gc_profile_record *record = gc_prof_record(objspace);
-        size_t live = objspace->profile.total_allocated_objects_at_gc_start - total_freed_objects(objspace);
-        size_t total = objspace->profile.heap_used_at_gc_start * HEAP_PAGE_OBJ_LIMIT;
-
-#if GC_PROFILE_MORE_DETAIL
-        record->heap_use_pages = objspace->profile.heap_used_at_gc_start;
-        record->heap_live_objects = live;
-        record->heap_free_objects = total - live;
-#endif
-
-        record->heap_total_objects = total;
-        record->heap_use_size = live * BASE_SLOT_SIZE;
-        record->heap_total_size = total * BASE_SLOT_SIZE;
-    }
-}
-
-/*
- *  call-seq:
- *    GC::Profiler.clear          -> nil
- *
- *  Clears the \GC profiler data.
- *
- */
-
-static VALUE
-gc_profile_clear(VALUE _)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    void *p = objspace->profile.records;
-    objspace->profile.records = NULL;
-    objspace->profile.size = 0;
-    objspace->profile.next_index = 0;
-    objspace->profile.current_record = 0;
-    free(p);
-    return Qnil;
-}
-
-/*
- *  call-seq:
- *     GC::Profiler.raw_data	-> [Hash, ...]
- *
- *  Returns an Array of individual raw profile data Hashes ordered
- *  from earliest to latest by +:GC_INVOKE_TIME+.
- *
- *  For example:
- *
- *    [
- *	{
- *	   :GC_TIME=>1.3000000000000858e-05,
- *	   :GC_INVOKE_TIME=>0.010634999999999999,
- *	   :HEAP_USE_SIZE=>289640,
- *	   :HEAP_TOTAL_SIZE=>588960,
- *	   :HEAP_TOTAL_OBJECTS=>14724,
- *	   :GC_IS_MARKED=>false
- *	},
- *      # ...
- *    ]
- *
- *  The keys mean:
- *
- *  +:GC_TIME+::
- *	Time elapsed in seconds for this GC run
- *  +:GC_INVOKE_TIME+::
- *	Time elapsed in seconds from startup to when the GC was invoked
- *  +:HEAP_USE_SIZE+::
- *	Total bytes of heap used
- *  +:HEAP_TOTAL_SIZE+::
- *	Total size of heap in bytes
- *  +:HEAP_TOTAL_OBJECTS+::
- *	Total number of objects
- *  +:GC_IS_MARKED+::
- *	Returns +true+ if the GC is in mark phase
- *
- *  If ruby was built with +GC_PROFILE_MORE_DETAIL+, you will also have access
- *  to the following hash keys:
- *
- *  +:GC_MARK_TIME+::
- *  +:GC_SWEEP_TIME+::
- *  +:ALLOCATE_INCREASE+::
- *  +:ALLOCATE_LIMIT+::
- *  +:HEAP_USE_PAGES+::
- *  +:HEAP_LIVE_OBJECTS+::
- *  +:HEAP_FREE_OBJECTS+::
- *  +:HAVE_FINALIZE+::
- *
- */
-
-static VALUE
-gc_profile_record_get(VALUE _)
-{
-    VALUE prof;
-    VALUE gc_profile = rb_ary_new();
-    size_t i;
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-
-    if (!objspace->profile.run) {
-        return Qnil;
-    }
-
-    for (i =0; i < objspace->profile.next_index; i++) {
-        gc_profile_record *record = &objspace->profile.records[i];
-
-        prof = rb_hash_new();
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_FLAGS")), gc_info_decode(objspace, rb_hash_new(), record->flags));
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_TIME")), DBL2NUM(record->gc_time));
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_INVOKE_TIME")), DBL2NUM(record->gc_invoke_time));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_USE_SIZE")), SIZET2NUM(record->heap_use_size));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_TOTAL_SIZE")), SIZET2NUM(record->heap_total_size));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_TOTAL_OBJECTS")), SIZET2NUM(record->heap_total_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("MOVED_OBJECTS")), SIZET2NUM(record->moved_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_IS_MARKED")), Qtrue);
-#if GC_PROFILE_MORE_DETAIL
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_MARK_TIME")), DBL2NUM(record->gc_mark_time));
-        rb_hash_aset(prof, ID2SYM(rb_intern("GC_SWEEP_TIME")), DBL2NUM(record->gc_sweep_time));
-        rb_hash_aset(prof, ID2SYM(rb_intern("ALLOCATE_INCREASE")), SIZET2NUM(record->allocate_increase));
-        rb_hash_aset(prof, ID2SYM(rb_intern("ALLOCATE_LIMIT")), SIZET2NUM(record->allocate_limit));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_USE_PAGES")), SIZET2NUM(record->heap_use_pages));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_LIVE_OBJECTS")), SIZET2NUM(record->heap_live_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("HEAP_FREE_OBJECTS")), SIZET2NUM(record->heap_free_objects));
-
-        rb_hash_aset(prof, ID2SYM(rb_intern("REMOVING_OBJECTS")), SIZET2NUM(record->removing_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("EMPTY_OBJECTS")), SIZET2NUM(record->empty_objects));
-
-        rb_hash_aset(prof, ID2SYM(rb_intern("HAVE_FINALIZE")), (record->flags & GPR_FLAG_HAVE_FINALIZE) ? Qtrue : Qfalse);
-#endif
-
-#if RGENGC_PROFILE > 0
-        rb_hash_aset(prof, ID2SYM(rb_intern("OLD_OBJECTS")), SIZET2NUM(record->old_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("REMEMBERED_NORMAL_OBJECTS")), SIZET2NUM(record->remembered_normal_objects));
-        rb_hash_aset(prof, ID2SYM(rb_intern("REMEMBERED_SHADY_OBJECTS")), SIZET2NUM(record->remembered_shady_objects));
-#endif
-        rb_ary_push(gc_profile, prof);
-    }
-
-    return gc_profile;
-}
-
-#if GC_PROFILE_MORE_DETAIL
-#define MAJOR_REASON_MAX 0x10
-
-static char *
-gc_profile_dump_major_reason(unsigned int flags, char *buff)
-{
-    unsigned int reason = flags & GPR_FLAG_MAJOR_MASK;
-    int i = 0;
-
-    if (reason == GPR_FLAG_NONE) {
-        buff[0] = '-';
-        buff[1] = 0;
-    }
-    else {
-#define C(x, s) \
-  if (reason & GPR_FLAG_MAJOR_BY_##x) { \
-      buff[i++] = #x[0]; \
-      if (i >= MAJOR_REASON_MAX) rb_bug("gc_profile_dump_major_reason: overflow"); \
-      buff[i] = 0; \
-  }
-        C(NOFREE, N);
-        C(OLDGEN, O);
-        C(SHADY,  S);
-#if RGENGC_ESTIMATE_OLDMALLOC
-        C(OLDMALLOC, M);
-#endif
-#undef C
-    }
-    return buff;
-}
-#endif
-
-
-
-static void
-gc_profile_dump_on(VALUE out, VALUE (*append)(VALUE, VALUE))
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    size_t count = objspace->profile.next_index;
-#ifdef MAJOR_REASON_MAX
-    char reason_str[MAJOR_REASON_MAX];
-#endif
-
-    if (objspace->profile.run && count /* > 1 */) {
-        size_t i;
-        const gc_profile_record *record;
-
-        append(out, rb_sprintf("GC %"PRIuSIZE" invokes.\n", objspace->profile.count));
-        append(out, rb_str_new_cstr("Index    Invoke Time(sec)       Use Size(byte)     Total Size(byte)         Total Object                    GC Time(ms)\n"));
-
-        for (i = 0; i < count; i++) {
-            record = &objspace->profile.records[i];
-            append(out, rb_sprintf("%5"PRIuSIZE" %19.3f %20"PRIuSIZE" %20"PRIuSIZE" %20"PRIuSIZE" %30.20f\n",
-                                   i+1, record->gc_invoke_time, record->heap_use_size,
-                                   record->heap_total_size, record->heap_total_objects, record->gc_time*1000));
-        }
-
-#if GC_PROFILE_MORE_DETAIL
-        const char *str = "\n\n" \
-                                    "More detail.\n" \
-                                    "Prepare Time = Previously GC's rest sweep time\n"
-                                    "Index Flags          Allocate Inc.  Allocate Limit"
-#if CALC_EXACT_MALLOC_SIZE
-                                    "  Allocated Size"
-#endif
-                                    "  Use Page     Mark Time(ms)    Sweep Time(ms)  Prepare Time(ms)  LivingObj    FreeObj RemovedObj   EmptyObj"
-#if RGENGC_PROFILE
-                                    " OldgenObj RemNormObj RemShadObj"
-#endif
-#if GC_PROFILE_DETAIL_MEMORY
-                                    " MaxRSS(KB) MinorFLT MajorFLT"
-#endif
-                                    "\n";
-        append(out, rb_str_new_cstr(str));
-
-        for (i = 0; i < count; i++) {
-            record = &objspace->profile.records[i];
-            append(out, rb_sprintf("%5"PRIuSIZE" %4s/%c/%6s%c %13"PRIuSIZE" %15"PRIuSIZE
-#if CALC_EXACT_MALLOC_SIZE
-                                   " %15"PRIuSIZE
-#endif
-                                   " %9"PRIuSIZE" %17.12f %17.12f %17.12f %10"PRIuSIZE" %10"PRIuSIZE" %10"PRIuSIZE" %10"PRIuSIZE
-#if RGENGC_PROFILE
-                                   "%10"PRIuSIZE" %10"PRIuSIZE" %10"PRIuSIZE
-#endif
-#if GC_PROFILE_DETAIL_MEMORY
-                                   "%11ld %8ld %8ld"
-#endif
-
-                                   "\n",
-                                   i+1,
-                                   gc_profile_dump_major_reason(record->flags, reason_str),
-                                   (record->flags & GPR_FLAG_HAVE_FINALIZE) ? 'F' : '.',
-                                   (record->flags & GPR_FLAG_NEWOBJ) ? "NEWOBJ" :
-                                   (record->flags & GPR_FLAG_MALLOC) ? "MALLOC" :
-                                   (record->flags & GPR_FLAG_METHOD) ? "METHOD" :
-                                   (record->flags & GPR_FLAG_CAPI)   ? "CAPI__" : "??????",
-                                   (record->flags & GPR_FLAG_STRESS) ? '!' : ' ',
-                                   record->allocate_increase, record->allocate_limit,
-#if CALC_EXACT_MALLOC_SIZE
-                                   record->allocated_size,
-#endif
-                                   record->heap_use_pages,
-                                   record->gc_mark_time*1000,
-                                   record->gc_sweep_time*1000,
-                                   record->prepare_time*1000,
-
-                                   record->heap_live_objects,
-                                   record->heap_free_objects,
-                                   record->removing_objects,
-                                   record->empty_objects
-#if RGENGC_PROFILE
-                                   ,
-                                   record->old_objects,
-                                   record->remembered_normal_objects,
-                                   record->remembered_shady_objects
-#endif
-#if GC_PROFILE_DETAIL_MEMORY
-                                   ,
-                                   record->maxrss / 1024,
-                                   record->minflt,
-                                   record->majflt
-#endif
-
-                       ));
-        }
-#endif
-    }
-}
-
-/*
- *  call-seq:
- *     GC::Profiler.result  -> String
- *
- *  Returns a profile data report such as:
- *
- *    GC 1 invokes.
- *    Index    Invoke Time(sec)       Use Size(byte)     Total Size(byte)         Total Object                    GC time(ms)
- *        1               0.012               159240               212940                10647         0.00000000000001530000
- */
-
-static VALUE
-gc_profile_result(VALUE _)
-{
-    VALUE str = rb_str_buf_new(0);
-    gc_profile_dump_on(str, rb_str_buf_append);
-    return str;
-}
-
-/*
- *  call-seq:
- *     GC::Profiler.report
- *     GC::Profiler.report(io)
- *
- *  Writes the GC::Profiler.result to <tt>$stdout</tt> or the given IO object.
- *
- */
-
-static VALUE
-gc_profile_report(int argc, VALUE *argv, VALUE self)
-{
-    VALUE out;
-
-    out = (!rb_check_arity(argc, 0, 1) ? rb_stdout : argv[0]);
-    gc_profile_dump_on(out, rb_io_write);
-
-    return Qnil;
-}
-
-/*
- *  call-seq:
- *     GC::Profiler.total_time	-> float
- *
- *  The total time used for garbage collection in seconds
- */
-
-static VALUE
-gc_profile_total_time(VALUE self)
-{
-    double time = 0;
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-
-    if (objspace->profile.run && objspace->profile.next_index > 0) {
-        size_t i;
-        size_t count = objspace->profile.next_index;
-
-        for (i = 0; i < count; i++) {
-            time += objspace->profile.records[i].gc_time;
-        }
-    }
-    return DBL2NUM(time);
-}
-
-/*
- *  call-seq:
- *    GC::Profiler.enabled?	-> true or false
- *
- *  The current status of \GC profile mode.
- */
-
-static VALUE
-gc_profile_enable_get(VALUE self)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    return objspace->profile.run ? Qtrue : Qfalse;
-}
-
-/*
- *  call-seq:
- *    GC::Profiler.enable	-> nil
- *
- *  Starts the \GC profiler.
- *
- */
-
-static VALUE
-gc_profile_enable(VALUE _)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    objspace->profile.run = TRUE;
-    objspace->profile.current_record = 0;
-    return Qnil;
-}
-
-/*
- *  call-seq:
- *    GC::Profiler.disable	-> nil
- *
- *  Stops the \GC profiler.
- *
- */
-
-static VALUE
-gc_profile_disable(VALUE _)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-
-    objspace->profile.run = FALSE;
-    objspace->profile.current_record = 0;
-    return Qnil;
-}
-
-/*
- *  call-seq:
- *     GC.verify_internal_consistency                  -> nil
- *
- *  Verify internal consistency.
- *
- *  This method is implementation specific.
- *  Now this method checks generational consistency
- *  if RGenGC is supported.
- */
-static VALUE
-gc_verify_internal_consistency_m(VALUE dummy)
-{
-    gc_verify_internal_consistency(rb_gc_get_objspace());
-    return Qnil;
-}
-
-#if GC_CAN_COMPILE_COMPACTION
-/*
- *  call-seq:
- *     GC.auto_compact = flag
- *
- *  Updates automatic compaction mode.
- *
- *  When enabled, the compactor will execute on every major collection.
- *
- *  Enabling compaction will degrade performance on major collections.
- */
-static VALUE
-gc_set_auto_compact(VALUE _, VALUE v)
-{
-    GC_ASSERT(GC_COMPACTION_SUPPORTED);
-
-    ruby_enable_autocompact = RTEST(v);
-
-#if RGENGC_CHECK_MODE
-    ruby_autocompact_compare_func = NULL;
-
-    if (SYMBOL_P(v)) {
-        ID id = RB_SYM2ID(v);
-        if (id == rb_intern("empty")) {
-            ruby_autocompact_compare_func = compare_free_slots;
-        }
-    }
-#endif
-
-    return v;
-}
-#else
-#  define gc_set_auto_compact rb_f_notimplement
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-/*
- *  call-seq:
- *     GC.auto_compact    -> true or false
- *
- *  Returns whether or not automatic compaction has been enabled.
- */
-static VALUE
-gc_get_auto_compact(VALUE _)
-{
-    return ruby_enable_autocompact ? Qtrue : Qfalse;
-}
-#else
-#  define gc_get_auto_compact rb_f_notimplement
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-/*
- *  call-seq:
- *     GC.latest_compact_info -> hash
- *
- * Returns information about object moved in the most recent \GC compaction.
- *
- * The returned +hash+ contains the following keys:
- *
- * [considered]
- *   Hash containing the type of the object as the key and the number of
- *   objects of that type that were considered for movement.
- * [moved]
- *   Hash containing the type of the object as the key and the number of
- *   objects of that type that were actually moved.
- * [moved_up]
- *   Hash containing the type of the object as the key and the number of
- *   objects of that type that were increased in size.
- * [moved_down]
- *   Hash containing the type of the object as the key and the number of
- *   objects of that type that were decreased in size.
- *
- * Some objects can't be moved (due to pinning) so these numbers can be used to
- * calculate compaction efficiency.
- */
-static VALUE
-gc_compact_stats(VALUE self)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    VALUE h = rb_hash_new();
-    VALUE considered = rb_hash_new();
-    VALUE moved = rb_hash_new();
-    VALUE moved_up = rb_hash_new();
-    VALUE moved_down = rb_hash_new();
-
-    for (size_t i = 0; i < T_MASK; i++) {
-        if (objspace->rcompactor.considered_count_table[i]) {
-            rb_hash_aset(considered, type_sym(i), SIZET2NUM(objspace->rcompactor.considered_count_table[i]));
-        }
-
-        if (objspace->rcompactor.moved_count_table[i]) {
-            rb_hash_aset(moved, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_count_table[i]));
-        }
-
-        if (objspace->rcompactor.moved_up_count_table[i]) {
-            rb_hash_aset(moved_up, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_up_count_table[i]));
-        }
-
-        if (objspace->rcompactor.moved_down_count_table[i]) {
-            rb_hash_aset(moved_down, type_sym(i), SIZET2NUM(objspace->rcompactor.moved_down_count_table[i]));
-        }
-    }
-
-    rb_hash_aset(h, ID2SYM(rb_intern("considered")), considered);
-    rb_hash_aset(h, ID2SYM(rb_intern("moved")), moved);
-    rb_hash_aset(h, ID2SYM(rb_intern("moved_up")), moved_up);
-    rb_hash_aset(h, ID2SYM(rb_intern("moved_down")), moved_down);
-
-    return h;
-}
-#else
-#  define gc_compact_stats rb_f_notimplement
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-/*
- *  call-seq:
- *     GC.compact -> hash
- *
- * This function compacts objects together in Ruby's heap. It eliminates
- * unused space (or fragmentation) in the heap by moving objects in to that
- * unused space.
- *
- * The returned +hash+ contains statistics about the objects that were moved;
- * see GC.latest_compact_info.
- *
- * This method is only expected to work on CRuby.
- *
- * To test whether \GC compaction is supported, use the idiom:
- *
- *   GC.respond_to?(:compact)
- */
-static VALUE
-gc_compact(VALUE self)
-{
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-    int full_marking_p = gc_config_full_mark_val;
-    gc_config_full_mark_set(TRUE);
-
-    /* Run GC with compaction enabled */
-    rb_gc_impl_start(rb_gc_get_objspace(), true, true, true, true);
-    gc_config_full_mark_set(full_marking_p);
-
-    return gc_compact_stats(self);
-}
-#else
-#  define gc_compact rb_f_notimplement
-#endif
-
-#if GC_CAN_COMPILE_COMPACTION
-struct desired_compaction_pages_i_data {
-    rb_objspace_t *objspace;
-    size_t required_slots[HEAP_COUNT];
-};
-
-static int
-desired_compaction_pages_i(struct heap_page *page, void *data)
-{
-    struct desired_compaction_pages_i_data *tdata = data;
-    rb_objspace_t *objspace = tdata->objspace;
-    VALUE vstart = (VALUE)page->start;
-    VALUE vend = vstart + (VALUE)(page->total_slots * page->heap->slot_size);
-
-
-    for (VALUE v = vstart; v != vend; v += page->heap->slot_size) {
-        asan_unpoisoning_object(v) {
-            /* skip T_NONEs; they won't be moved */
-            if (BUILTIN_TYPE(v) != T_NONE) {
-                rb_heap_t *dest_pool = gc_compact_destination_pool(objspace, page->heap, v);
-                size_t dest_pool_idx = dest_pool - heaps;
-                tdata->required_slots[dest_pool_idx]++;
-            }
-        }
-    }
-
-    return 0;
-}
-
-/* call-seq:
- *    GC.verify_compaction_references(toward: nil, double_heap: false) -> hash
- *
- * Verify compaction reference consistency.
- *
- * This method is implementation specific.  During compaction, objects that
- * were moved are replaced with T_MOVED objects.  No object should have a
- * reference to a T_MOVED object after compaction.
- *
- * This function expands the heap to ensure room to move all objects,
- * compacts the heap to make sure everything moves, updates all references,
- * then performs a full \GC.  If any object contains a reference to a T_MOVED
- * object, that object should be pushed on the mark stack, and will
- * make a SEGV.
- */
-static VALUE
-gc_verify_compaction_references(int argc, VALUE* argv, VALUE self)
-{
-    static ID keywords[3] = {0};
-    if (!keywords[0]) {
-        keywords[0] = rb_intern("toward");
-        keywords[1] = rb_intern("double_heap");
-        keywords[2] = rb_intern("expand_heap");
-    }
-
-    VALUE options;
-    rb_scan_args_kw(rb_keyword_given_p(), argc, argv, ":", &options);
-
-    VALUE arguments[3] = { Qnil, Qfalse, Qfalse };
-    int kwarg_count = rb_get_kwargs(options, keywords, 0, 3, arguments);
-    bool toward_empty = kwarg_count > 0 && SYMBOL_P(arguments[0]) && SYM2ID(arguments[0]) == rb_intern("empty");
-    bool expand_heap = (kwarg_count > 1 && RTEST(arguments[1])) || (kwarg_count > 2 && RTEST(arguments[2]));
-
-    rb_objspace_t *objspace = rb_gc_get_objspace();
-
-    /* Clear the heap. */
-    rb_gc_impl_start(objspace, true, true, true, false);
-
-    unsigned int lev = rb_gc_vm_lock();
-    {
-        gc_rest(objspace);
-
-        /* if both double_heap and expand_heap are set, expand_heap takes precedence */
-        if (expand_heap) {
-            struct desired_compaction_pages_i_data desired_compaction = {
-                .objspace = objspace,
-                .required_slots = {0},
-            };
-            /* Work out how many objects want to be in each size pool, taking account of moves */
-            objspace_each_pages(objspace, desired_compaction_pages_i, &desired_compaction, TRUE);
-
-            /* Find out which pool has the most pages */
-            size_t max_existing_pages = 0;
-            for (int i = 0; i < HEAP_COUNT; i++) {
-                rb_heap_t *heap = &heaps[i];
-                max_existing_pages = MAX(max_existing_pages, heap->total_pages);
-            }
-
-            /* Add pages to each size pool so that compaction is guaranteed to move every object */
-            for (int i = 0; i < HEAP_COUNT; i++) {
-                rb_heap_t *heap = &heaps[i];
-
-                size_t pages_to_add = 0;
-                /*
-                 * Step 1: Make sure every pool has the same number of pages, by adding empty pages
-                 * to smaller pools. This is required to make sure the compact cursor can advance
-                 * through all of the pools in `gc_sweep_compact` without hitting the "sweep &
-                 * compact cursors met" condition on some pools before fully compacting others
-                 */
-                pages_to_add += max_existing_pages - heap->total_pages;
-                /*
-                 * Step 2: Now add additional free pages to each size pool sufficient to hold all objects
-                 * that want to be in that size pool, whether moved into it or moved within it
-                 */
-                objspace->heap_pages.allocatable_slots = desired_compaction.required_slots[i];
-                while (objspace->heap_pages.allocatable_slots > 0) {
-                    heap_page_allocate_and_initialize(objspace, heap);
-                }
-                /*
-                 * Step 3: Add two more pages so that the compact & sweep cursors will meet _after_ all objects
-                 * have been moved, and not on the last iteration of the `gc_sweep_compact` loop
-                 */
-                pages_to_add += 2;
-
-                for (; pages_to_add > 0; pages_to_add--) {
-                    heap_page_allocate_and_initialize_force(objspace, heap);
-                }
-            }
-        }
-
-        if (toward_empty) {
-            objspace->rcompactor.compare_func = compare_free_slots;
-        }
-    }
-    rb_gc_vm_unlock(lev);
-
-    rb_gc_impl_start(rb_gc_get_objspace(), true, true, true, true);
-
-    rb_objspace_reachable_objects_from_root(root_obj_check_moved_i, objspace);
-    objspace_each_objects(objspace, heap_check_moved_i, objspace, TRUE);
-
-    objspace->rcompactor.compare_func = NULL;
-
-    return gc_compact_stats(self);
-}
-#else
-# define gc_verify_compaction_references rb_f_notimplement
-#endif
-
-void
-rb_gc_impl_objspace_free(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    if (is_lazy_sweeping(objspace))
-        rb_bug("lazy sweeping underway when freeing object space");
-
-    free(objspace->profile.records);
-    objspace->profile.records = NULL;
-
-    for (size_t i = 0; i < rb_darray_size(objspace->heap_pages.sorted); i++) {
-        heap_page_free(objspace, rb_darray_get(objspace->heap_pages.sorted, i));
-    }
-    rb_darray_free(objspace->heap_pages.sorted);
-    heap_pages_lomem = 0;
-    heap_pages_himem = 0;
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-        heap->total_pages = 0;
-        heap->total_slots = 0;
-    }
-
-    st_free_table(objspace->id_to_obj_tbl);
-    st_free_table(objspace->obj_to_id_tbl);
-
-    free_stack_chunks(&objspace->mark_stack);
-    mark_stack_free_cache(&objspace->mark_stack);
-
-    rb_darray_free(objspace->weak_references);
-
-    free(objspace);
-}
-
-#if MALLOC_ALLOCATED_SIZE
-/*
- *  call-seq:
- *     GC.malloc_allocated_size -> Integer
- *
- *  Returns the size of memory allocated by malloc().
- *
- *  Only available if ruby was built with +CALC_EXACT_MALLOC_SIZE+.
- */
-
-static VALUE
-gc_malloc_allocated_size(VALUE self)
-{
-    return UINT2NUM(rb_objspace.malloc_params.allocated_size);
-}
-
-/*
- *  call-seq:
- *     GC.malloc_allocations -> Integer
- *
- *  Returns the number of malloc() allocations.
- *
- *  Only available if ruby was built with +CALC_EXACT_MALLOC_SIZE+.
- */
-
-static VALUE
-gc_malloc_allocations(VALUE self)
-{
-    return UINT2NUM(rb_objspace.malloc_params.allocations);
-}
-#endif
-
-void *
-rb_gc_impl_objspace_alloc(void)
-{
-    rb_objspace_t *objspace = calloc1(sizeof(rb_objspace_t));
-
-    return objspace;
-}
-
-void
-rb_gc_impl_objspace_init(void *objspace_ptr)
-{
-    rb_objspace_t *objspace = objspace_ptr;
-
-    gc_config_full_mark_set(TRUE);
-
-    objspace->flags.measure_gc = true;
-    malloc_limit = gc_params.malloc_limit_min;
-    objspace->finalize_deferred_pjob = rb_postponed_job_preregister(0, gc_finalize_deferred, objspace);
-    if (objspace->finalize_deferred_pjob == POSTPONED_JOB_HANDLE_INVALID) {
-        rb_bug("Could not preregister postponed job for GC");
-    }
-
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        rb_heap_t *heap = &heaps[i];
-
-        heap->slot_size = (1 << i) * BASE_SLOT_SIZE;
-
-        ccan_list_head_init(&heap->pages);
-    }
-
-    rb_darray_make(&objspace->heap_pages.sorted, 0);
-    rb_darray_make(&objspace->weak_references, 0);
-
-    // TODO: debug why on Windows Ruby crashes on boot when GC is on.
-#ifdef _WIN32
-    dont_gc_on();
-#endif
-
-#if defined(INIT_HEAP_PAGE_ALLOC_USE_MMAP)
-    /* Need to determine if we can use mmap at runtime. */
-    heap_page_alloc_use_mmap = INIT_HEAP_PAGE_ALLOC_USE_MMAP;
-#endif
-    objspace->next_object_id = OBJ_ID_INITIAL;
-    objspace->id_to_obj_tbl = st_init_table(&object_id_hash_type);
-    objspace->obj_to_id_tbl = st_init_numtable();
-#if RGENGC_ESTIMATE_OLDMALLOC
-    objspace->rgengc.oldmalloc_increase_limit = gc_params.oldmalloc_limit_min;
-#endif
-    /* Set size pools allocatable pages. */
-    for (int i = 0; i < HEAP_COUNT; i++) {
-        /* Set the default value of heap_init_slots. */
-        gc_params.heap_init_slots[i] = GC_HEAP_INIT_SLOTS;
-    }
-
-    init_mark_stack(&objspace->mark_stack);
-
-    objspace->profile.invoke_time = getrusage_time();
-    finalizer_table = st_init_numtable();
-}
-
-void
-rb_gc_impl_init(void)
-{
-    VALUE gc_constants = rb_hash_new();
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("DEBUG")), GC_DEBUG ? Qtrue : Qfalse);
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("BASE_SLOT_SIZE")), SIZET2NUM(BASE_SLOT_SIZE - RVALUE_OVERHEAD));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("RVALUE_OVERHEAD")), SIZET2NUM(RVALUE_OVERHEAD));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("HEAP_PAGE_OBJ_LIMIT")), SIZET2NUM(HEAP_PAGE_OBJ_LIMIT));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("HEAP_PAGE_BITMAP_SIZE")), SIZET2NUM(HEAP_PAGE_BITMAP_SIZE));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("HEAP_PAGE_SIZE")), SIZET2NUM(HEAP_PAGE_SIZE));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("HEAP_COUNT")), LONG2FIX(HEAP_COUNT));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("RVARGC_MAX_ALLOCATE_SIZE")), LONG2FIX(heap_slot_size(HEAP_COUNT - 1)));
-    rb_hash_aset(gc_constants, ID2SYM(rb_intern("RVALUE_OLD_AGE")), LONG2FIX(RVALUE_OLD_AGE));
-    if (RB_BUG_INSTEAD_OF_RB_MEMERROR+0) {
-        rb_hash_aset(gc_constants, ID2SYM(rb_intern("RB_BUG_INSTEAD_OF_RB_MEMERROR")), Qtrue);
-    }
-    OBJ_FREEZE(gc_constants);
-    /* Internal constants in the garbage collector. */
-    rb_define_const(rb_mGC, "INTERNAL_CONSTANTS", gc_constants);
-
-    if (GC_COMPACTION_SUPPORTED) {
-        rb_define_singleton_method(rb_mGC, "compact", gc_compact, 0);
-        rb_define_singleton_method(rb_mGC, "auto_compact", gc_get_auto_compact, 0);
-        rb_define_singleton_method(rb_mGC, "auto_compact=", gc_set_auto_compact, 1);
-        rb_define_singleton_method(rb_mGC, "latest_compact_info", gc_compact_stats, 0);
-        rb_define_singleton_method(rb_mGC, "verify_compaction_references", gc_verify_compaction_references, -1);
-    }
-    else {
-        rb_define_singleton_method(rb_mGC, "compact", rb_f_notimplement, 0);
-        rb_define_singleton_method(rb_mGC, "auto_compact", rb_f_notimplement, 0);
-        rb_define_singleton_method(rb_mGC, "auto_compact=", rb_f_notimplement, 1);
-        rb_define_singleton_method(rb_mGC, "latest_compact_info", rb_f_notimplement, 0);
-        rb_define_singleton_method(rb_mGC, "verify_compaction_references", rb_f_notimplement, -1);
-    }
-
-    /* internal methods */
-    rb_define_singleton_method(rb_mGC, "verify_internal_consistency", gc_verify_internal_consistency_m, 0);
-
-#if MALLOC_ALLOCATED_SIZE
-    rb_define_singleton_method(rb_mGC, "malloc_allocated_size", gc_malloc_allocated_size, 0);
-    rb_define_singleton_method(rb_mGC, "malloc_allocations", gc_malloc_allocations, 0);
-#endif
-
-    VALUE rb_mProfiler = rb_define_module_under(rb_mGC, "Profiler");
-    rb_define_singleton_method(rb_mProfiler, "enabled?", gc_profile_enable_get, 0);
-    rb_define_singleton_method(rb_mProfiler, "enable", gc_profile_enable, 0);
-    rb_define_singleton_method(rb_mProfiler, "raw_data", gc_profile_record_get, 0);
-    rb_define_singleton_method(rb_mProfiler, "disable", gc_profile_disable, 0);
-    rb_define_singleton_method(rb_mProfiler, "clear", gc_profile_clear, 0);
-    rb_define_singleton_method(rb_mProfiler, "result", gc_profile_result, 0);
-    rb_define_singleton_method(rb_mProfiler, "report", gc_profile_report, -1);
-    rb_define_singleton_method(rb_mProfiler, "total_time", gc_profile_total_time, 0);
-
-    {
-        VALUE opts;
-        /* \GC build options */
-        rb_define_const(rb_mGC, "OPTS", opts = rb_ary_new());
-#define OPT(o) if (o) rb_ary_push(opts, rb_interned_str(#o, sizeof(#o) - 1))
-        OPT(GC_DEBUG);
-        OPT(USE_RGENGC);
-        OPT(RGENGC_DEBUG);
-        OPT(RGENGC_CHECK_MODE);
-        OPT(RGENGC_PROFILE);
-        OPT(RGENGC_ESTIMATE_OLDMALLOC);
-        OPT(GC_PROFILE_MORE_DETAIL);
-        OPT(GC_ENABLE_LAZY_SWEEP);
-        OPT(CALC_EXACT_MALLOC_SIZE);
-        OPT(MALLOC_ALLOCATED_SIZE);
-        OPT(MALLOC_ALLOCATED_SIZE_CHECK);
-        OPT(GC_PROFILE_DETAIL_MEMORY);
-        OPT(GC_COMPACTION_SUPPORTED);
-#undef OPT
-        OBJ_FREEZE(opts);
-    }
-}
diff --git a/gc/gc.h b/gc/gc.h
index 592435bc9d..0ed2f7bab3 100644
--- a/gc/gc.h
+++ b/gc/gc.h
@@ -11,6 +11,29 @@
  */
 #include "ruby/ruby.h"
 
+#if USE_SHARED_GC
+#include "ruby/thread_native.h"
+
+struct rb_gc_vm_context {
+    rb_nativethread_lock_t lock;
+
+    struct rb_execution_context_struct *ec;
+};
+
+typedef int (*vm_table_foreach_callback_func)(VALUE value, void *data);
+typedef int (*vm_table_update_callback_func)(VALUE *value, void *data);
+
+
+enum rb_gc_vm_weak_tables {
+    RB_GC_VM_CI_TABLE,
+    RB_GC_VM_OVERLOADED_CME_TABLE,
+    RB_GC_VM_GLOBAL_SYMBOLS_TABLE,
+    RB_GC_VM_GENERIC_IV_TABLE,
+    RB_GC_VM_FROZEN_STRINGS_TABLE,
+    RB_GC_VM_WEAK_TABLE_COUNT
+};
+#endif
+
 RUBY_SYMBOL_EXPORT_BEGIN
 unsigned int rb_gc_vm_lock(void);
 void rb_gc_vm_unlock(unsigned int lev);
@@ -31,6 +54,7 @@ void rb_gc_set_pending_interrupt(void);
 void rb_gc_unset_pending_interrupt(void);
 void rb_gc_obj_free_vm_weak_references(VALUE obj);
 bool rb_gc_obj_free(void *objspace, VALUE obj);
+void rb_gc_save_machine_context(void);
 void rb_gc_mark_roots(void *objspace, const char **categoryp);
 void rb_gc_ractor_newobj_cache_foreach(void (*func)(void *cache, void *data), void *data);
 bool rb_gc_multi_ractor_p(void);
@@ -44,6 +68,16 @@ void rb_gc_set_shape(VALUE obj, uint32_t shape_id);
 uint32_t rb_gc_rebuild_shape(VALUE obj, size_t heap_id);
 size_t rb_obj_memsize_of(VALUE obj);
 void rb_gc_prepare_heap_process_object(VALUE obj);
+bool ruby_free_at_exit_p(void);
+
+#if USE_SHARED_GC
+bool rb_gc_event_hook_required_p(rb_event_flag_t event);
+void *rb_gc_get_ractor_newobj_cache(void);
+void rb_gc_initialize_vm_context(struct rb_gc_vm_context *context);
+void rb_gc_worker_thread_set_vm_context(struct rb_gc_vm_context *context);
+void rb_gc_worker_thread_unset_vm_context(struct rb_gc_vm_context *context);
+void rb_gc_vm_weak_table_foreach(vm_table_foreach_callback_func callback, vm_table_update_callback_func update_callback, void *data, enum rb_gc_vm_weak_tables table);
+#endif
 RUBY_SYMBOL_EXPORT_END
 
 void rb_ractor_finish_marking(void);
diff --git a/gc/gc_impl.h b/gc/gc_impl.h
index 14416d217c..4c2fec978e 100644
--- a/gc/gc_impl.h
+++ b/gc/gc_impl.h
@@ -83,6 +83,9 @@ GC_IMPL_FN void rb_gc_impl_shutdown_call_finalizer(void *objspace_ptr);
 // Object ID
 GC_IMPL_FN VALUE rb_gc_impl_object_id(void *objspace_ptr, VALUE obj);
 GC_IMPL_FN VALUE rb_gc_impl_object_id_to_ref(void *objspace_ptr, VALUE object_id);
+// Forking
+GC_IMPL_FN void rb_gc_impl_before_fork(void *objspace_ptr);
+GC_IMPL_FN void rb_gc_impl_after_fork(void *objspace_ptr, rb_pid_t pid);
 // Statistics
 GC_IMPL_FN void rb_gc_impl_set_measure_total_time(void *objspace_ptr, VALUE flag);
 GC_IMPL_FN bool rb_gc_impl_get_measure_total_time(void *objspace_ptr);
diff --git a/imemo.c b/imemo.c
index ac094eb931..49b925413b 100644
--- a/imemo.c
+++ b/imemo.c
@@ -532,7 +532,6 @@ rb_imemo_free(VALUE obj)
       case imemo_callinfo:{
         const struct rb_callinfo *ci = ((const struct rb_callinfo *)obj);
 
-        rb_vm_ci_free(ci);
         if (ci->kwarg) {
             ((struct rb_callinfo_kwarg *)ci->kwarg)->references--;
             if (ci->kwarg->references == 0) xfree((void *)ci->kwarg);
diff --git a/internal/gc.h b/internal/gc.h
index 2280564049..4af5bc9861 100644
--- a/internal/gc.h
+++ b/internal/gc.h
@@ -197,7 +197,7 @@ static inline void *ruby_sized_xrealloc_inlined(void *ptr, size_t new_size, size
 static inline void *ruby_sized_xrealloc2_inlined(void *ptr, size_t new_count, size_t elemsiz, size_t old_count) RUBY_ATTR_RETURNS_NONNULL RUBY_ATTR_ALLOC_SIZE((2, 3));
 static inline void ruby_sized_xfree_inlined(void *ptr, size_t size);
 
-void *rb_gc_ractor_cache_alloc(void);
+void *rb_gc_ractor_cache_alloc(rb_ractor_t *ractor);
 void rb_gc_ractor_cache_free(void *cache);
 
 bool rb_gc_size_allocatable_p(size_t size);
@@ -213,6 +213,9 @@ void rb_gc_ref_update_table_values_only(st_table *tbl);
 
 void rb_gc_initial_stress_set(VALUE flag);
 
+void rb_gc_before_fork(void);
+void rb_gc_after_fork(rb_pid_t pid);
+
 #define rb_gc_mark_and_move_ptr(ptr) do { \
     VALUE _obj = (VALUE)*(ptr); \
     rb_gc_mark_and_move(&_obj); \
diff --git a/method.h b/method.h
index fdc7c263d1..030c3cc3d1 100644
--- a/method.h
+++ b/method.h
@@ -237,6 +237,7 @@ st_index_t rb_hash_method_entry(st_index_t hash, const rb_method_entry_t *me);
 
 VALUE rb_method_entry_location(const rb_method_entry_t *me);
 
+void rb_free_method_entry_vm_weak_references(const rb_method_entry_t *me);
 void rb_free_method_entry(const rb_method_entry_t *me);
 
 const rb_method_entry_t *rb_method_entry_clone(const rb_method_entry_t *me);
diff --git a/process.c b/process.c
index ef4757ab23..ad81c2d80f 100644
--- a/process.c
+++ b/process.c
@@ -1676,12 +1676,15 @@ after_exec(void)
 static void
 before_fork_ruby(void)
 {
+    rb_gc_before_fork();
     before_exec();
 }
 
 static void
 after_fork_ruby(rb_pid_t pid)
 {
+    rb_gc_after_fork(pid);
+
     if (pid == 0) {
         // child
         clear_pid_cache();
diff --git a/ractor.c b/ractor.c
index 785a965598..76d697a96f 100644
--- a/ractor.c
+++ b/ractor.c
@@ -1940,7 +1940,7 @@ vm_insert_ractor0(rb_vm_t *vm, rb_ractor_t *r, bool single_ractor_mode)
         VM_ASSERT(r == ruby_single_main_ractor);
     }
     else {
-        r->newobj_cache = rb_gc_ractor_cache_alloc();
+        r->newobj_cache = rb_gc_ractor_cache_alloc(r);
     }
 }
 
@@ -2041,7 +2041,7 @@ rb_ractor_main_alloc(void)
     r->loc = Qnil;
     r->name = Qnil;
     r->pub.self = Qnil;
-    r->newobj_cache = rb_gc_ractor_cache_alloc();
+    r->newobj_cache = rb_gc_ractor_cache_alloc(r);
     ruby_single_main_ractor = r;
 
     return r;
diff --git a/string.c b/string.c
index d20bcbde95..0fd1c59a90 100644
--- a/string.c
+++ b/string.c
@@ -1676,17 +1676,6 @@ rb_str_tmp_new(long len)
 void
 rb_str_free(VALUE str)
 {
-    if (FL_TEST(str, RSTRING_FSTR)) {
-        st_data_t fstr = (st_data_t)str;
-
-        RB_VM_LOCK_ENTER();
-        {
-            st_delete(rb_vm_fstring_table(), &fstr, NULL);
-            RB_DEBUG_COUNTER_INC(obj_str_fstr);
-        }
-        RB_VM_LOCK_LEAVE();
-    }
-
     if (STR_EMBED_P(str)) {
         RB_DEBUG_COUNTER_INC(obj_str_embed);
     }
diff --git a/variable.c b/variable.c
index bc255b6b5f..e7d2e35f7e 100644
--- a/variable.c
+++ b/variable.c
@@ -1065,6 +1065,12 @@ generic_ivtbl_no_ractor_check(VALUE obj)
     return generic_ivtbl(obj, 0, false);
 }
 
+struct st_table *
+rb_generic_ivtbl_get(void)
+{
+    return generic_iv_tbl_;
+}
+
 int
 rb_gen_ivtbl_get(VALUE obj, ID id, struct gen_ivtbl **ivtbl)
 {
diff --git a/vm_method.c b/vm_method.c
index e52015b9ac..9ab035b978 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -541,11 +541,16 @@ rb_method_definition_release(rb_method_definition_t *def)
 static void delete_overloaded_cme(const rb_callable_method_entry_t *cme);
 
 void
-rb_free_method_entry(const rb_method_entry_t *me)
+rb_free_method_entry_vm_weak_references(const rb_method_entry_t *me)
 {
     if (me->def && me->def->iseq_overload) {
         delete_overloaded_cme((const rb_callable_method_entry_t *)me);
     }
+}
+
+void
+rb_free_method_entry(const rb_method_entry_t *me)
+{
     rb_method_definition_release(me->def);
 }