Get rid of frozen shapes.

Instead `shape_id_t` higher bits contain flags, and the first one tells whether the shape is frozen. This has multiple benefits: - Can check if a shape is frozen with a single bit check instead of dereferencing a pointer. - Guarantees it is always possible to transition to frozen. - This allow reclaiming `FL_FREEZE` (not done yet). The downside is you have to be careful to preserve these flags when transitioning.
author: Jean Boussier <[email protected]> 2025-05-27 15:53:45 +0200
committer: Jean Boussier <[email protected]> 2025-06-04 07:59:20 +0200
commit: 625d6a9cbb0ed617b28115e4e3cb063e52481635 ()
tree: 610cfd170759de7e0b65369dfe4e3421a2f699bf /shape.c
parent: 6b7e3395a4ab69f5eaefb983243a8e4cad7f8abf (diff)
1 files changed, 66 insertions, 109 deletions
@@ -20,17 +20,7 @@
 #define SHAPE_DEBUG (VM_CHECK_MODE > 0)
 #endif
-#if SIZEOF_SHAPE_T == 4
-#if RUBY_DEBUG
-#define SHAPE_BUFFER_SIZE 0x8000
-#else
-#define SHAPE_BUFFER_SIZE 0x80000
-#endif
-#else
-#define SHAPE_BUFFER_SIZE 0x8000
-#endif
-
-#define ROOT_TOO_COMPLEX_SHAPE_ID 0x2
 #define REDBLACK_CACHE_SIZE (SHAPE_BUFFER_SIZE * 32)
@@ -53,14 +43,6 @@ ID ruby_internal_object_id; // extern
 #define BLACK 0x0
 #define RED 0x1
-enum shape_flags {
- SHAPE_FL_FROZEN = 1 << 0,
- SHAPE_FL_HAS_OBJECT_ID = 1 << 1,
- SHAPE_FL_TOO_COMPLEX = 1 << 2,
-
- SHAPE_FL_NON_CANONICAL_MASK = SHAPE_FL_FROZEN | SHAPE_FL_HAS_OBJECT_ID,
-};
-
 static redblack_node_t *
 redblack_left(redblack_node_t *node)
 {
@@ -373,7 +355,7 @@ static const rb_data_type_t shape_tree_type = {
 */
 static inline shape_id_t
-rb_shape_id(rb_shape_t *shape)
 {
 if (shape == NULL) {
 return INVALID_SHAPE_ID;
@@ -381,6 +363,24 @@ rb_shape_id(rb_shape_t *shape)
 return (shape_id_t)(shape - GET_SHAPE_TREE()->shape_list);
 }
 static inline bool
 shape_too_complex_p(rb_shape_t *shape)
 {
@@ -402,9 +402,10 @@ rb_shape_each_shape_id(each_shape_callback callback, void *data)
 RUBY_FUNC_EXPORTED rb_shape_t *
 rb_shape_lookup(shape_id_t shape_id)
 {
- RUBY_ASSERT(shape_id != INVALID_SHAPE_ID);
- return &GET_SHAPE_TREE()->shape_list[shape_id];
 }
 RUBY_FUNC_EXPORTED shape_id_t
@@ -466,7 +467,7 @@ rb_shape_alloc_with_parent_id(ID edge_name, shape_id_t parent_id)
 static rb_shape_t *
 rb_shape_alloc(ID edge_name, rb_shape_t *parent, enum shape_type type)
 {
- rb_shape_t *shape = rb_shape_alloc_with_parent_id(edge_name, rb_shape_id(parent));
 shape->type = (uint8_t)type;
 shape->flags = parent->flags;
 shape->heap_index = parent->heap_index;
@@ -530,10 +531,6 @@ rb_shape_alloc_new_child(ID id, rb_shape_t *shape, enum shape_type shape_type)
 redblack_cache_ancestors(new_shape);
 }
 break;
- case SHAPE_FROZEN:
- new_shape->next_field_index = shape->next_field_index;
- new_shape->flags |= SHAPE_FL_FROZEN;
- break;
 case SHAPE_OBJ_TOO_COMPLEX:
 case SHAPE_ROOT:
 case SHAPE_T_OBJECT:
@@ -626,8 +623,8 @@ retry:
 static rb_shape_t *
 get_next_shape_internal(rb_shape_t *shape, ID id, enum shape_type shape_type, bool *variation_created, bool new_variations_allowed)
 {
- // There should never be outgoing edges from "too complex", except for SHAPE_FROZEN and SHAPE_OBJ_ID
- RUBY_ASSERT(!shape_too_complex_p(shape) || shape_type == SHAPE_FROZEN || shape_type == SHAPE_OBJ_ID);
 if (rb_multi_ractor_p()) {
 return get_next_shape_internal_atomic(shape, id, shape_type, variation_created, new_variations_allowed);
@@ -692,12 +689,6 @@ get_next_shape_internal(rb_shape_t *shape, ID id, enum shape_type shape_type, bo
 return res;
 }
-static inline bool
-shape_frozen_p(rb_shape_t *shape)
-{
- return SHAPE_FL_FROZEN & shape->flags;
-}
-
 static rb_shape_t *
 remove_shape_recursive(rb_shape_t *shape, ID id, rb_shape_t **removed_shape)
 {
@@ -749,12 +740,13 @@ rb_shape_transition_remove_ivar(VALUE obj, ID id, shape_id_t *removed_shape_id)
 rb_shape_t *shape = RSHAPE(shape_id);
 RUBY_ASSERT(!shape_too_complex_p(shape));
 rb_shape_t *removed_shape = NULL;
 rb_shape_t *new_shape = remove_shape_recursive(shape, id, &removed_shape);
 if (new_shape) {
- *removed_shape_id = rb_shape_id(removed_shape);
- return rb_shape_id(new_shape);
 }
 return shape_id;
 }
@@ -765,22 +757,7 @@ rb_shape_transition_frozen(VALUE obj)
 RUBY_ASSERT(RB_OBJ_FROZEN(obj));
 shape_id_t shape_id = rb_obj_shape_id(obj);
- if (shape_id == ROOT_SHAPE_ID) {
- return SPECIAL_CONST_SHAPE_ID;
- }
-
- rb_shape_t *shape = RSHAPE(shape_id);
- RUBY_ASSERT(shape);
-
- if (shape_frozen_p(shape)) {
- return shape_id;
- }
-
- bool dont_care;
- rb_shape_t *next_shape = get_next_shape_internal(shape, id_frozen, SHAPE_FROZEN, &dont_care, true);
-
- RUBY_ASSERT(next_shape);
- return rb_shape_id(next_shape);
 }
 static rb_shape_t *
@@ -788,11 +765,6 @@ shape_transition_too_complex(rb_shape_t *original_shape)
 {
 rb_shape_t *next_shape = RSHAPE(ROOT_TOO_COMPLEX_SHAPE_ID);
- if (original_shape->flags & SHAPE_FL_FROZEN) {
- bool dont_care;
- next_shape = get_next_shape_internal(next_shape, id_frozen, SHAPE_FROZEN, &dont_care, false);
- }
-
 if (original_shape->flags & SHAPE_FL_HAS_OBJECT_ID) {
 bool dont_care;
 next_shape = get_next_shape_internal(next_shape, ruby_internal_object_id, SHAPE_OBJ_ID, &dont_care, false);
@@ -804,8 +776,8 @@ shape_transition_too_complex(rb_shape_t *original_shape)
 shape_id_t
 rb_shape_transition_complex(VALUE obj)
 {
- rb_shape_t *original_shape = obj_shape(obj);
- return rb_shape_id(shape_transition_too_complex(original_shape));
 }
 static inline bool
@@ -823,7 +795,9 @@ rb_shape_has_object_id(shape_id_t shape_id)
 shape_id_t
 rb_shape_transition_object_id(VALUE obj)
 {
- rb_shape_t* shape = obj_shape(obj);
 RUBY_ASSERT(shape);
 if (shape->flags & SHAPE_FL_HAS_OBJECT_ID) {
@@ -836,7 +810,7 @@ rb_shape_transition_object_id(VALUE obj)
 shape = get_next_shape_internal(shape, ruby_internal_object_id, SHAPE_OBJ_ID, &dont_care, true);
 }
 RUBY_ASSERT(shape);
- return rb_shape_id(shape);
 }
 /*
@@ -856,7 +830,7 @@ rb_shape_get_next_iv_shape(shape_id_t shape_id, ID id)
 {
 rb_shape_t *shape = RSHAPE(shape_id);
 rb_shape_t *next_shape = shape_get_next_iv_shape(shape, id);
- return rb_shape_id(next_shape);
 }
 static bool
@@ -877,7 +851,6 @@ shape_get_iv_index(rb_shape_t *shape, ID id, attr_index_t *value)
 return false;
 case SHAPE_OBJ_TOO_COMPLEX:
 case SHAPE_OBJ_ID:
- case SHAPE_FROZEN:
 rb_bug("Ivar should not exist on transition");
 }
 }
@@ -945,13 +918,17 @@ shape_get_next(rb_shape_t *shape, VALUE obj, ID id, bool emit_warnings)
 shape_id_t
 rb_shape_transition_add_ivar(VALUE obj, ID id)
 {
- return rb_shape_id(shape_get_next(obj_shape(obj), obj, id, true));
 }
 shape_id_t
 rb_shape_transition_add_ivar_no_warnings(VALUE obj, ID id)
 {
- return rb_shape_id(shape_get_next(obj_shape(obj), obj, id, false));
 }
 // Same as rb_shape_get_iv_index, but uses a provided valid shape id and index
@@ -987,13 +964,13 @@ rb_shape_get_iv_index_with_hint(shape_id_t shape_id, ID id, attr_index_t *value,
 if (shape_hint == shape) {
 // We've found a common ancestor so use the index hint
 *value = index_hint;
- *shape_id_hint = rb_shape_id(shape);
 return true;
 }
 if (shape->edge_name == id) {
 // We found the matching id before a common ancestor
 *value = shape->next_field_index - 1;
- *shape_id_hint = rb_shape_id(shape);
 return true;
 }
@@ -1080,7 +1057,6 @@ shape_traverse_from_new_root(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
 switch ((enum shape_type)dest_shape->type) {
 case SHAPE_IVAR:
 case SHAPE_OBJ_ID:
- case SHAPE_FROZEN:
 if (!next_shape->edges) {
 return NULL;
 }
@@ -1120,17 +1096,17 @@ rb_shape_traverse_from_new_root(shape_id_t initial_shape_id, shape_id_t dest_sha
 {
 rb_shape_t *initial_shape = RSHAPE(initial_shape_id);
 rb_shape_t *dest_shape = RSHAPE(dest_shape_id);
- return rb_shape_id(shape_traverse_from_new_root(initial_shape, dest_shape));
 }
 // Rebuild a similar shape with the same ivars but starting from
 // a different SHAPE_T_OBJECT, and don't cary over non-canonical transitions
-// such as SHAPE_FROZEN or SHAPE_OBJ_ID.
 rb_shape_t *
 rb_shape_rebuild_shape(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
 {
- RUBY_ASSERT(rb_shape_id(initial_shape) != ROOT_TOO_COMPLEX_SHAPE_ID);
- RUBY_ASSERT(rb_shape_id(dest_shape) != ROOT_TOO_COMPLEX_SHAPE_ID);
 rb_shape_t *midway_shape;
@@ -1138,7 +1114,7 @@ rb_shape_rebuild_shape(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
 if (dest_shape->type != initial_shape->type) {
 midway_shape = rb_shape_rebuild_shape(initial_shape, RSHAPE(dest_shape->parent_id));
- if (UNLIKELY(rb_shape_id(midway_shape) == ROOT_TOO_COMPLEX_SHAPE_ID)) {
 return midway_shape;
 }
 }
@@ -1152,7 +1128,6 @@ rb_shape_rebuild_shape(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
 break;
 case SHAPE_OBJ_ID:
 case SHAPE_ROOT:
- case SHAPE_FROZEN:
 case SHAPE_T_OBJECT:
 break;
 case SHAPE_OBJ_TOO_COMPLEX:
@@ -1166,7 +1141,7 @@ rb_shape_rebuild_shape(rb_shape_t *initial_shape, rb_shape_t *dest_shape)
 shape_id_t
 rb_shape_rebuild(shape_id_t initial_shape_id, shape_id_t dest_shape_id)
 {
- return rb_shape_id(rb_shape_rebuild_shape(RSHAPE(initial_shape_id), RSHAPE(dest_shape_id)));
 }
 void
@@ -1266,8 +1241,7 @@ static VALUE
 shape_frozen(VALUE self)
 {
 shape_id_t shape_id = NUM2INT(rb_struct_getmember(self, rb_intern("id")));
- rb_shape_t *shape = RSHAPE(shape_id);
- return RBOOL(shape_frozen_p(shape));
 }
 static VALUE
@@ -1290,12 +1264,13 @@ parse_key(ID key)
 static VALUE rb_shape_edge_name(rb_shape_t *shape);
 static VALUE
-rb_shape_t_to_rb_cShape(rb_shape_t *shape)
 {
 VALUE rb_cShape = rb_const_get(rb_cRubyVM, rb_intern("Shape"));
 VALUE obj = rb_struct_new(rb_cShape,
- INT2NUM(rb_shape_id(shape)),
 INT2NUM(shape->parent_id),
 rb_shape_edge_name(shape),
 INT2NUM(shape->next_field_index),
@@ -1309,7 +1284,7 @@ rb_shape_t_to_rb_cShape(rb_shape_t *shape)
 static enum rb_id_table_iterator_result
 rb_edges_to_hash(ID key, VALUE value, void *ref)
 {
- rb_hash_aset(*(VALUE *)ref, parse_key(key), rb_shape_t_to_rb_cShape((rb_shape_t *)value));
 return ID_TABLE_CONTINUE;
 }
@@ -1360,7 +1335,7 @@ rb_shape_parent(VALUE self)
 rb_shape_t *shape;
 shape = RSHAPE(NUM2INT(rb_struct_getmember(self, rb_intern("id"))));
 if (shape->parent_id != INVALID_SHAPE_ID) {
- return rb_shape_t_to_rb_cShape(RSHAPE(shape->parent_id));
 }
 else {
 return Qnil;
@@ -1370,13 +1345,13 @@ rb_shape_parent(VALUE self)
 static VALUE
 rb_shape_debug_shape(VALUE self, VALUE obj)
 {
- return rb_shape_t_to_rb_cShape(obj_shape(obj));
 }
 static VALUE
 rb_shape_root_shape(VALUE self)
 {
- return rb_shape_t_to_rb_cShape(rb_shape_get_root_shape());
 }
 static VALUE
@@ -1420,10 +1395,8 @@ shape_to_h(rb_shape_t *shape)
 {
 VALUE rb_shape = rb_hash_new();
- rb_hash_aset(rb_shape, ID2SYM(rb_intern("id")), INT2NUM(rb_shape_id(shape)));
- VALUE shape_edges = shape->edges;
- rb_hash_aset(rb_shape, ID2SYM(rb_intern("edges")), edges(shape_edges));
- RB_GC_GUARD(shape_edges);
 if (shape == rb_shape_get_root_shape()) {
 rb_hash_aset(rb_shape, ID2SYM(rb_intern("parent_id")), INT2NUM(ROOT_SHAPE_ID));
@@ -1449,7 +1422,7 @@ rb_shape_find_by_id(VALUE mod, VALUE id)
 if (shape_id >= GET_SHAPE_TREE()->next_shape_id) {
 rb_raise(rb_eArgError, "Shape ID %d is out of bounds\n", shape_id);
 }
- return rb_shape_t_to_rb_cShape(RSHAPE(shape_id));
 }
 #endif
@@ -1511,24 +1484,14 @@ Init_default_shapes(void)
 root->type = SHAPE_ROOT;
 root->heap_index = 0;
 GET_SHAPE_TREE()->root_shape = root;
- RUBY_ASSERT(rb_shape_id(GET_SHAPE_TREE()->root_shape) == ROOT_SHAPE_ID);
 bool dont_care;
- // Special const shape
-#if RUBY_DEBUG
- rb_shape_t *special_const_shape =
-#endif
- get_next_shape_internal(root, id_frozen, SHAPE_FROZEN, &dont_care, true);
- RUBY_ASSERT(rb_shape_id(special_const_shape) == SPECIAL_CONST_SHAPE_ID);
- RUBY_ASSERT(SPECIAL_CONST_SHAPE_ID == (GET_SHAPE_TREE()->next_shape_id - 1));
- RUBY_ASSERT(shape_frozen_p(special_const_shape));
-
 rb_shape_t *too_complex_shape = rb_shape_alloc_with_parent_id(0, ROOT_SHAPE_ID);
 too_complex_shape->type = SHAPE_OBJ_TOO_COMPLEX;
 too_complex_shape->flags |= SHAPE_FL_TOO_COMPLEX;
 too_complex_shape->heap_index = 0;
- RUBY_ASSERT(ROOT_TOO_COMPLEX_SHAPE_ID == (GET_SHAPE_TREE()->next_shape_id - 1));
- RUBY_ASSERT(rb_shape_id(too_complex_shape) == ROOT_TOO_COMPLEX_SHAPE_ID);
 // Make shapes for T_OBJECT
 size_t *sizes = rb_gc_heap_sizes();
@@ -1539,17 +1502,12 @@ Init_default_shapes(void)
 t_object_shape->capacity = (uint32_t)((sizes[i] - offsetof(struct RObject, as.ary)) / sizeof(VALUE));
 t_object_shape->edges = rb_managed_id_table_new(256);
 t_object_shape->ancestor_index = LEAF;
- RUBY_ASSERT(rb_shape_id(t_object_shape) == rb_shape_root(i));
 }
 // Prebuild TOO_COMPLEX variations so that they already exist if we ever need them after we
 // ran out of shapes.
- rb_shape_t *shape;
- shape = get_next_shape_internal(too_complex_shape, id_frozen, SHAPE_FROZEN, &dont_care, true);
- get_next_shape_internal(shape, ruby_internal_object_id, SHAPE_OBJ_ID, &dont_care, true);
-
- shape = get_next_shape_internal(too_complex_shape, ruby_internal_object_id, SHAPE_OBJ_ID, &dont_care, true);
- get_next_shape_internal(shape, id_frozen, SHAPE_FROZEN, &dont_care, true);
 }
 void
@@ -1584,7 +1542,6 @@ Init_shape(void)
 rb_define_const(rb_cShape, "SHAPE_ROOT", INT2NUM(SHAPE_ROOT));
 rb_define_const(rb_cShape, "SHAPE_IVAR", INT2NUM(SHAPE_IVAR));
 rb_define_const(rb_cShape, "SHAPE_T_OBJECT", INT2NUM(SHAPE_T_OBJECT));
- rb_define_const(rb_cShape, "SHAPE_FROZEN", INT2NUM(SHAPE_FROZEN));
 rb_define_const(rb_cShape, "SHAPE_ID_NUM_BITS", INT2NUM(SHAPE_ID_NUM_BITS));
 rb_define_const(rb_cShape, "SHAPE_FLAG_SHIFT", INT2NUM(SHAPE_FLAG_SHIFT));
 rb_define_const(rb_cShape, "SPECIAL_CONST_SHAPE_ID", INT2NUM(SPECIAL_CONST_SHAPE_ID));
author	Jean Boussier <[email protected]>	2025-05-27 15:53:45 +0200
committer	Jean Boussier <[email protected]>	2025-06-04 07:59:20 +0200
commit	625d6a9cbb0ed617b28115e4e3cb063e52481635 ()
tree	610cfd170759de7e0b65369dfe4e3421a2f699bf /shape.c
parent	6b7e3395a4ab69f5eaefb983243a8e4cad7f8abf (diff)