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ruby--ruby/internal/class.h
Jemma Issroff 9ddfd2ca00 This commit implements the Object Shapes technique in CRuby.
Object Shapes is used for accessing instance variables and representing the
"frozenness" of objects.  Object instances have a "shape" and the shape
represents some attributes of the object (currently which instance variables are
set and the "frozenness").  Shapes form a tree data structure, and when a new
instance variable is set on an object, that object "transitions" to a new shape
in the shape tree.  Each shape has an ID that is used for caching. The shape
structure is independent of class, so objects of different types can have the
same shape.

For example:

```ruby
class Foo
  def initialize
    # Starts with shape id 0
    @a = 1 # transitions to shape id 1
    @b = 1 # transitions to shape id 2
  end
end

class Bar
  def initialize
    # Starts with shape id 0
    @a = 1 # transitions to shape id 1
    @b = 1 # transitions to shape id 2
  end
end

foo = Foo.new # `foo` has shape id 2
bar = Bar.new # `bar` has shape id 2
```

Both `foo` and `bar` instances have the same shape because they both set
instance variables of the same name in the same order.

This technique can help to improve inline cache hits as well as generate more
efficient machine code in JIT compilers.

This commit also adds some methods for debugging shapes on objects.  See
`RubyVM::Shape` for more details.

For more context on Object Shapes, see [Feature: #18776]

Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
Co-Authored-By: Eileen M. Uchitelle <eileencodes@gmail.com>
Co-Authored-By: John Hawthorn <john@hawthorn.email>
2022-09-26 09:21:30 -07:00

213 lines
7 KiB
C

#ifndef INTERNAL_CLASS_H /*-*-C-*-vi:se ft=c:*/
#define INTERNAL_CLASS_H
/**
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @brief Internal header for Class.
*/
#include "id_table.h" /* for struct rb_id_table */
#include "internal/gc.h" /* for RB_OBJ_WRITE */
#include "internal/serial.h" /* for rb_serial_t */
#include "ruby/internal/stdbool.h" /* for bool */
#include "ruby/intern.h" /* for rb_alloc_func_t */
#include "ruby/ruby.h" /* for struct RBasic */
#include "shape.h"
#ifdef RCLASS_SUPER
# undef RCLASS_SUPER
#endif
struct rb_subclass_entry {
VALUE klass;
struct rb_subclass_entry *next;
struct rb_subclass_entry *prev;
};
struct rb_iv_index_tbl_entry {
uint32_t idx;
shape_id_t source_shape_id;
shape_id_t dest_shape_id;
};
struct rb_cvar_class_tbl_entry {
uint32_t index;
rb_serial_t global_cvar_state;
VALUE class_value;
};
struct rb_classext_struct {
struct st_table *iv_tbl;
#if SIZEOF_SERIAL_T == SIZEOF_VALUE /* otherwise m_tbl is in struct RClass */
struct rb_id_table *m_tbl;
#endif
struct rb_id_table *const_tbl;
struct rb_id_table *callable_m_tbl;
struct rb_id_table *cc_tbl; /* ID -> [[ci, cc1], cc2, ...] */
struct rb_id_table *cvc_tbl;
size_t superclass_depth;
VALUE *superclasses;
struct rb_subclass_entry *subclasses;
struct rb_subclass_entry *subclass_entry;
/**
* In the case that this is an `ICLASS`, `module_subclasses` points to the link
* in the module's `subclasses` list that indicates that the klass has been
* included. Hopefully that makes sense.
*/
struct rb_subclass_entry *module_subclass_entry;
#if SIZEOF_SERIAL_T != SIZEOF_VALUE && !USE_RVARGC /* otherwise class_serial is in struct RClass */
rb_serial_t class_serial;
#endif
const VALUE origin_;
const VALUE refined_class;
rb_alloc_func_t allocator;
const VALUE includer;
uint32_t max_iv_count;
uint16_t shape_id;
};
struct RClass {
struct RBasic basic;
VALUE super;
#if !USE_RVARGC
struct rb_classext_struct *ptr;
#endif
#if SIZEOF_SERIAL_T == SIZEOF_VALUE
/* Class serial is as wide as VALUE. Place it here. */
rb_serial_t class_serial;
#else
/* Class serial does not fit into struct RClass. Place m_tbl instead. */
struct rb_id_table *m_tbl;
# if USE_RVARGC
rb_serial_t *class_serial_ptr;
# endif
#endif
};
typedef struct rb_subclass_entry rb_subclass_entry_t;
typedef struct rb_classext_struct rb_classext_t;
#if USE_RVARGC
# define RCLASS_EXT(c) ((rb_classext_t *)((char *)(c) + sizeof(struct RClass)))
#else
# define RCLASS_EXT(c) (RCLASS(c)->ptr)
#endif
#define RCLASS_IV_TBL(c) (RCLASS_EXT(c)->iv_tbl)
#define RCLASS_CONST_TBL(c) (RCLASS_EXT(c)->const_tbl)
#if SIZEOF_SERIAL_T == SIZEOF_VALUE
# define RCLASS_M_TBL(c) (RCLASS_EXT(c)->m_tbl)
#else
# define RCLASS_M_TBL(c) (RCLASS(c)->m_tbl)
#endif
#define RCLASS_CALLABLE_M_TBL(c) (RCLASS_EXT(c)->callable_m_tbl)
#define RCLASS_CC_TBL(c) (RCLASS_EXT(c)->cc_tbl)
#define RCLASS_CVC_TBL(c) (RCLASS_EXT(c)->cvc_tbl)
#define RCLASS_ORIGIN(c) (RCLASS_EXT(c)->origin_)
#define RCLASS_REFINED_CLASS(c) (RCLASS_EXT(c)->refined_class)
#if SIZEOF_SERIAL_T == SIZEOF_VALUE
# define RCLASS_SERIAL(c) (RCLASS(c)->class_serial)
#else
# if USE_RVARGC
# define RCLASS_SERIAL(c) (*RCLASS(c)->class_serial_ptr)
# else
# define RCLASS_SERIAL(c) (RCLASS_EXT(c)->class_serial)
# endif
#endif
#define RCLASS_INCLUDER(c) (RCLASS_EXT(c)->includer)
#define RCLASS_SUBCLASS_ENTRY(c) (RCLASS_EXT(c)->subclass_entry)
#define RCLASS_MODULE_SUBCLASS_ENTRY(c) (RCLASS_EXT(c)->module_subclass_entry)
#define RCLASS_ALLOCATOR(c) (RCLASS_EXT(c)->allocator)
#define RCLASS_SUBCLASSES(c) (RCLASS_EXT(c)->subclasses)
#define RCLASS_SUPERCLASS_DEPTH(c) (RCLASS_EXT(c)->superclass_depth)
#define RCLASS_SUPERCLASSES(c) (RCLASS_EXT(c)->superclasses)
#define RICLASS_IS_ORIGIN FL_USER0
#define RCLASS_CLONED FL_USER1
#define RCLASS_SUPERCLASSES_INCLUDE_SELF FL_USER2
#define RICLASS_ORIGIN_SHARED_MTBL FL_USER3
/* class.c */
void rb_class_subclass_add(VALUE super, VALUE klass);
void rb_class_remove_from_super_subclasses(VALUE);
void rb_class_update_superclasses(VALUE);
size_t rb_class_superclasses_memsize(VALUE);
void rb_class_remove_subclass_head(VALUE);
int rb_singleton_class_internal_p(VALUE sklass);
VALUE rb_class_boot(VALUE);
VALUE rb_class_s_alloc(VALUE klass);
VALUE rb_module_s_alloc(VALUE klass);
void rb_module_set_initialized(VALUE module);
void rb_module_check_initializable(VALUE module);
VALUE rb_make_metaclass(VALUE, VALUE);
VALUE rb_include_class_new(VALUE, VALUE);
void rb_class_foreach_subclass(VALUE klass, void (*f)(VALUE, VALUE), VALUE);
void rb_class_detach_subclasses(VALUE);
void rb_class_detach_module_subclasses(VALUE);
void rb_class_remove_from_module_subclasses(VALUE);
VALUE rb_obj_methods(int argc, const VALUE *argv, VALUE obj);
VALUE rb_obj_protected_methods(int argc, const VALUE *argv, VALUE obj);
VALUE rb_obj_private_methods(int argc, const VALUE *argv, VALUE obj);
VALUE rb_obj_public_methods(int argc, const VALUE *argv, VALUE obj);
VALUE rb_class_undefined_instance_methods(VALUE mod);
VALUE rb_special_singleton_class(VALUE);
VALUE rb_singleton_class_clone_and_attach(VALUE obj, VALUE attach);
VALUE rb_singleton_class_get(VALUE obj);
void rb_undef_methods_from(VALUE klass, VALUE super);
static inline void RCLASS_SET_ORIGIN(VALUE klass, VALUE origin);
static inline void RICLASS_SET_ORIGIN_SHARED_MTBL(VALUE iclass);
static inline VALUE RCLASS_SUPER(VALUE klass);
static inline VALUE RCLASS_SET_SUPER(VALUE klass, VALUE super);
static inline void RCLASS_SET_INCLUDER(VALUE iclass, VALUE klass);
MJIT_SYMBOL_EXPORT_BEGIN
VALUE rb_class_inherited(VALUE, VALUE);
VALUE rb_keyword_error_new(const char *, VALUE);
MJIT_SYMBOL_EXPORT_END
static inline void
RCLASS_SET_ORIGIN(VALUE klass, VALUE origin)
{
RB_OBJ_WRITE(klass, &RCLASS_ORIGIN(klass), origin);
if (klass != origin) FL_SET(origin, RICLASS_IS_ORIGIN);
}
static inline void
RICLASS_SET_ORIGIN_SHARED_MTBL(VALUE iclass)
{
FL_SET(iclass, RICLASS_ORIGIN_SHARED_MTBL);
}
static inline bool
RICLASS_OWNS_M_TBL_P(VALUE iclass)
{
return FL_TEST_RAW(iclass, RICLASS_IS_ORIGIN | RICLASS_ORIGIN_SHARED_MTBL) == RICLASS_IS_ORIGIN;
}
static inline void
RCLASS_SET_INCLUDER(VALUE iclass, VALUE klass)
{
RB_OBJ_WRITE(iclass, &RCLASS_INCLUDER(iclass), klass);
}
static inline VALUE
RCLASS_SUPER(VALUE klass)
{
return RCLASS(klass)->super;
}
static inline VALUE
RCLASS_SET_SUPER(VALUE klass, VALUE super)
{
if (super) {
rb_class_remove_from_super_subclasses(klass);
rb_class_subclass_add(super, klass);
}
RB_OBJ_WRITE(klass, &RCLASS(klass)->super, super);
rb_class_update_superclasses(klass);
return super;
}
#endif /* INTERNAL_CLASS_H */