diff options
Diffstat (limited to 'shape.h')
| -rw-r--r-- | shape.h | 625 |
1 files changed, 625 insertions, 0 deletions
diff --git a/shape.h b/shape.h new file mode 100644 index 0000000000..61fadca5ba --- /dev/null +++ b/shape.h @@ -0,0 +1,625 @@ +#ifndef RUBY_SHAPE_H +#define RUBY_SHAPE_H + +#include "internal/gc.h" +#include "internal/struct.h" + +typedef uint8_t attr_index_t; +typedef uint32_t shape_id_t; +#define SHAPE_ID_NUM_BITS 32 +#define SHAPE_ID_OFFSET_NUM_BITS 19 + +STATIC_ASSERT(shape_id_num_bits, SHAPE_ID_NUM_BITS == sizeof(shape_id_t) * CHAR_BIT); + +#define SHAPE_BUFFER_SIZE (1 << SHAPE_ID_OFFSET_NUM_BITS) +#define SHAPE_ID_OFFSET_MASK (SHAPE_BUFFER_SIZE - 1) + +#define SHAPE_ID_HEAP_INDEX_BITS 4 +#define SHAPE_ID_HEAP_INDEX_MAX (((attr_index_t)1 << SHAPE_ID_HEAP_INDEX_BITS) - 1) + +#define SHAPE_ID_HEAP_INDEX_OFFSET SHAPE_ID_OFFSET_NUM_BITS +#define SHAPE_ID_FL_USHIFT (SHAPE_ID_OFFSET_NUM_BITS + SHAPE_ID_HEAP_INDEX_BITS) + +// shape_id_t bits: +// 0-18 SHAPE_ID_OFFSET_MASK +// index in rb_shape_tree.shape_list. Allow to access `rb_shape_t *`. +// This is the part that describe how fields are laid out in memory. +// 19-22 SHAPE_ID_HEAP_INDEX_MASK +// index in rb_shape_tree.capacities. Allow to access slot size. +// Currently always 0 except for T_OBJECT. +// 23 SHAPE_ID_FL_FROZEN +// Whether the object is frozen or not. +// 24 SHAPE_ID_FL_HAS_OBJECT_ID +// Whether the object has an `SHAPE_OBJ_ID` transition. +// 25 SHAPE_ID_FL_COMPLEX +// The object is backed by a `st_table`. + +enum shape_id_fl_type { +#define RBIMPL_SHAPE_ID_FL(n) (1<<(SHAPE_ID_FL_USHIFT+n)) + + SHAPE_ID_HEAP_INDEX_MASK = ((1 << SHAPE_ID_HEAP_INDEX_BITS) - 1) << SHAPE_ID_HEAP_INDEX_OFFSET, + + SHAPE_ID_FL_COMPLEX = RBIMPL_SHAPE_ID_FL(0), + SHAPE_ID_FL_FROZEN = RBIMPL_SHAPE_ID_FL(1), + SHAPE_ID_FL_HAS_OBJECT_ID = RBIMPL_SHAPE_ID_FL(2), + + SHAPE_ID_FL_NON_CANONICAL_MASK = SHAPE_ID_FL_FROZEN | SHAPE_ID_FL_HAS_OBJECT_ID, + SHAPE_ID_FLAGS_MASK = SHAPE_ID_HEAP_INDEX_MASK | SHAPE_ID_FL_NON_CANONICAL_MASK | SHAPE_ID_FL_COMPLEX, + +#undef RBIMPL_SHAPE_ID_FL +}; + +// This mask allows to check if a shape_id contains any ivar. +// It relies on ROOT_SHAPE_WITH_OBJ_ID==1. +enum shape_id_mask { + SHAPE_ID_HAS_IVAR_MASK = SHAPE_ID_FL_COMPLEX | (SHAPE_ID_OFFSET_MASK - 1), +}; + +// The interpreter doesn't care about frozen status, slot size or object id when reading ivars. +// So we normalize shape_id by clearing these bits to improve cache hits. +// JITs however might care about some of it. +#define SHAPE_ID_READ_ONLY_MASK (~(SHAPE_ID_FL_FROZEN | SHAPE_ID_HEAP_INDEX_MASK | SHAPE_ID_FL_HAS_OBJECT_ID)) +// For write it's the same idea, but here we do care about frozen status. +#define SHAPE_ID_WRITE_MASK (~(SHAPE_ID_HEAP_INDEX_MASK | SHAPE_ID_FL_HAS_OBJECT_ID)) + +typedef uint32_t redblack_id_t; + +#define SHAPE_FLAG_SHIFT ((SIZEOF_VALUE * CHAR_BIT) - SHAPE_ID_NUM_BITS) +#define SHAPE_FLAG_MASK (((VALUE)-1) >> SHAPE_ID_NUM_BITS) + +#define SHAPE_MAX_VARIATIONS 8 + +#define INVALID_SHAPE_ID (SHAPE_BUFFER_SIZE - 1) +#define ATTR_INDEX_NOT_SET ((attr_index_t)-1) + +#define ROOT_SHAPE_ID 0x0 +#define ROOT_SHAPE_WITH_OBJ_ID 0x1 +#define ROOT_COMPLEX_SHAPE_ID (ROOT_SHAPE_ID | SHAPE_ID_FL_COMPLEX) +#define ROOT_COMPLEX_WITH_OBJ_ID (ROOT_SHAPE_WITH_OBJ_ID | SHAPE_ID_FL_COMPLEX | SHAPE_ID_FL_HAS_OBJECT_ID) + +enum shape_type { + SHAPE_ROOT, + SHAPE_IVAR, + SHAPE_OBJ_ID, +}; + +struct rb_shape { + VALUE edges; // id_table from ID (ivar) to next shape + ID edge_name; // ID (ivar) for transition from parent to rb_shape + redblack_id_t ancestor_index; + shape_id_t parent_offset; + attr_index_t next_field_index; // Fields are either ivars or internal properties like `object_id` + attr_index_t capacity; // Total capacity of the object with this shape + enum shape_type type : 8; +}; + +typedef struct rb_shape rb_shape_t; + +enum shape_flags { + SHAPE_FL_FROZEN = 1 << 0, + SHAPE_FL_HAS_OBJECT_ID = 1 << 1, + SHAPE_FL_COMPLEX = 1 << 2, + + SHAPE_FL_NON_CANONICAL_MASK = SHAPE_FL_FROZEN | SHAPE_FL_HAS_OBJECT_ID, +}; + +typedef struct { + rb_shape_t *shape_list; + attr_index_t max_capacity; + attr_index_t heaps_count; + attr_index_t capacities[SHAPE_ID_HEAP_INDEX_MAX]; +} rb_shape_tree_t; + +RUBY_SYMBOL_EXPORT_BEGIN +RUBY_EXTERN rb_shape_tree_t rb_shape_tree; +RUBY_SYMBOL_EXPORT_END + +size_t rb_shapes_cache_size(void); +size_t rb_shapes_count(void); + +static inline shape_id_t +RBASIC_SHAPE_ID(VALUE obj) +{ + RUBY_ASSERT(!RB_SPECIAL_CONST_P(obj)); + RUBY_ASSERT(!RB_TYPE_P(obj, T_IMEMO) || IMEMO_TYPE_P(obj, imemo_fields)); +#if RBASIC_SHAPE_ID_FIELD + return (shape_id_t)((RBASIC(obj)->shape_id)); +#else + return (shape_id_t)((RBASIC(obj)->flags) >> SHAPE_FLAG_SHIFT); +#endif +} + +// Same as RBASIC_SHAPE_ID but with flags that have no impact +// on reads removed. e.g. Remove FL_FROZEN. +static inline shape_id_t +RBASIC_SHAPE_ID_FOR_READ(VALUE obj) +{ + return RBASIC_SHAPE_ID(obj) & SHAPE_ID_READ_ONLY_MASK; +} + +#if RUBY_DEBUG +bool rb_shape_verify_consistency(VALUE obj, shape_id_t shape_id); +#endif + +static inline void +RBASIC_SET_SHAPE_ID_NO_CHECKS(VALUE obj, shape_id_t shape_id) +{ +#if RBASIC_SHAPE_ID_FIELD + RBASIC(obj)->shape_id = (VALUE)shape_id; +#else + // Object shapes are occupying top bits + RBASIC(obj)->flags &= SHAPE_FLAG_MASK; + RBASIC(obj)->flags |= ((VALUE)(shape_id) << SHAPE_FLAG_SHIFT); +#endif +} + +static inline void +RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id) +{ + RUBY_ASSERT(!RB_SPECIAL_CONST_P(obj)); + RUBY_ASSERT(!RB_TYPE_P(obj, T_IMEMO) || IMEMO_TYPE_P(obj, imemo_fields)); + + RBASIC_SET_SHAPE_ID_NO_CHECKS(obj, shape_id); + + RUBY_ASSERT(rb_shape_verify_consistency(obj, shape_id)); +} + +static inline shape_id_t +RSHAPE_FLAGS(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_FLAGS_MASK; +} + +static inline shape_id_t +RSHAPE_OFFSET(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_OFFSET_MASK; +} + +static inline rb_shape_t * +RSHAPE(shape_id_t shape_id) +{ + shape_id_t offset = RSHAPE_OFFSET(shape_id); + RUBY_ASSERT(offset != INVALID_SHAPE_ID); + return &rb_shape_tree.shape_list[offset]; +} + +int32_t rb_shape_id_offset(void); + +RUBY_FUNC_EXPORTED shape_id_t rb_obj_shape_id(VALUE obj); +shape_id_t rb_shape_get_next_iv_shape(shape_id_t shape_id, ID id); +bool rb_shape_get_iv_index(shape_id_t shape_id, ID id, attr_index_t *value); +bool rb_shape_get_iv_index_with_hint(shape_id_t shape_id, ID id, attr_index_t *value, shape_id_t *shape_id_hint); +bool rb_shape_find_ivar(shape_id_t shape_id, ID id, shape_id_t *ivar_shape); + +typedef int rb_shape_foreach_transition_callback(shape_id_t shape_id, void *data); +bool rb_shape_foreach_field(shape_id_t shape_id, rb_shape_foreach_transition_callback func, void *data); + +shape_id_t rb_shape_transition_add_ivar_no_warnings(shape_id_t shape_id, ID id, VALUE klass); + +shape_id_t rb_shape_object_id(shape_id_t original_shape_id); +shape_id_t rb_shape_rebuild(shape_id_t initial_shape_id, shape_id_t dest_shape_id); +void rb_shape_copy_fields(VALUE dest, VALUE *dest_buf, shape_id_t dest_shape_id, VALUE *src_buf, shape_id_t src_shape_id); +void rb_shape_copy_complex_ivars(VALUE dest, VALUE obj, shape_id_t src_shape_id, st_table *fields_table); + +static inline bool +rb_shape_frozen_p(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_FL_FROZEN; +} + +static inline bool +rb_shape_complex_p(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_FL_COMPLEX; +} + +static inline bool +rb_obj_shape_complex_p(VALUE obj) +{ + return !RB_SPECIAL_CONST_P(obj) && rb_shape_complex_p(RBASIC_SHAPE_ID(obj)); +} + +static inline bool +rb_shape_has_object_id(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_FL_HAS_OBJECT_ID; +} + +static inline bool +rb_shape_canonical_p(shape_id_t shape_id) +{ + return !(shape_id & SHAPE_ID_FL_NON_CANONICAL_MASK); +} + +static inline uint8_t +rb_shape_heap_index(shape_id_t shape_id) +{ + return (uint8_t)((shape_id & SHAPE_ID_HEAP_INDEX_MASK) >> SHAPE_ID_HEAP_INDEX_OFFSET); +} + +static inline shape_id_t +rb_shape_root(size_t heap_id) +{ + shape_id_t heap_index = (shape_id_t)(heap_id + 1); + shape_id_t heap_flags = heap_index << SHAPE_ID_HEAP_INDEX_OFFSET; + + RUBY_ASSERT((heap_flags & SHAPE_ID_HEAP_INDEX_MASK) == heap_flags); + RUBY_ASSERT(rb_shape_heap_index(heap_flags) == heap_index); + + return ROOT_SHAPE_ID | heap_flags; +} + +static inline shape_id_t +RSHAPE_PARENT_OFFSET(shape_id_t shape_id) +{ + return RSHAPE(shape_id)->parent_offset; +} + +static inline bool +RSHAPE_DIRECT_CHILD_P(shape_id_t parent_offset, shape_id_t child_id) +{ + return RSHAPE_PARENT_OFFSET(child_id) == RSHAPE_OFFSET(parent_offset); +} + +static inline enum shape_type +RSHAPE_TYPE(shape_id_t shape_id) +{ + return RSHAPE(shape_id)->type; +} + +static inline bool +RSHAPE_TYPE_P(shape_id_t shape_id, enum shape_type type) +{ + return RSHAPE_TYPE(shape_id) == type; +} + +static inline attr_index_t +RSHAPE_EMBEDDED_CAPACITY(shape_id_t shape_id) +{ + uint8_t heap_index = rb_shape_heap_index(shape_id); + if (heap_index) { + return rb_shape_tree.capacities[heap_index - 1]; + } + return 0; +} + +static inline attr_index_t +RSHAPE_CAPACITY(shape_id_t shape_id) +{ + attr_index_t embedded_capacity = RSHAPE_EMBEDDED_CAPACITY(shape_id); + + if (embedded_capacity > RSHAPE(shape_id)->capacity) { + return embedded_capacity; + } + else { + return RSHAPE(shape_id)->capacity; + } +} + +static inline attr_index_t +RSHAPE_LEN(shape_id_t shape_id) +{ + return RSHAPE(shape_id)->next_field_index; +} + +static inline attr_index_t +RSHAPE_INDEX(shape_id_t shape_id) +{ + RUBY_ASSERT(RSHAPE_LEN(shape_id) > 0); + return RSHAPE_LEN(shape_id) - 1; +} + +static inline ID +RSHAPE_EDGE_NAME(shape_id_t shape_id) +{ + return RSHAPE(shape_id)->edge_name; +} + +static inline uint32_t +ROBJECT_FIELDS_CAPACITY(VALUE obj) +{ + RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT); + // Asking for capacity doesn't make sense when the object is using + // a hash table for storing instance variables + RUBY_ASSERT(!rb_obj_shape_complex_p(obj)); + return RSHAPE_CAPACITY(RBASIC_SHAPE_ID(obj)); +} + +static inline st_table * +ROBJECT_FIELDS_HASH(VALUE obj) +{ + RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT); + RUBY_ASSERT(rb_obj_shape_complex_p(obj)); + RUBY_ASSERT(FL_TEST_RAW(obj, ROBJECT_HEAP)); + + return ROBJECT(obj)->as.hash; +} + +static inline void +ROBJECT_SET_FIELDS_HASH(VALUE obj, st_table *tbl) +{ + RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT); + RUBY_ASSERT(rb_obj_shape_complex_p(obj)); + RUBY_ASSERT(FL_TEST_RAW(obj, ROBJECT_HEAP)); + + ROBJECT(obj)->as.hash = tbl; +} + +static inline uint32_t +ROBJECT_FIELDS_COUNT_COMPLEX(VALUE obj) +{ + return (uint32_t)rb_st_table_size(ROBJECT_FIELDS_HASH(obj)); +} + +static inline uint32_t +ROBJECT_FIELDS_COUNT_NOT_COMPLEX(VALUE obj) +{ + RBIMPL_ASSERT_TYPE(obj, RUBY_T_OBJECT); + RUBY_ASSERT(!rb_obj_shape_complex_p(obj)); + return RSHAPE(RBASIC_SHAPE_ID(obj))->next_field_index; +} + +static inline uint32_t +ROBJECT_FIELDS_COUNT(VALUE obj) +{ + if (rb_obj_shape_complex_p(obj)) { + return ROBJECT_FIELDS_COUNT_COMPLEX(obj); + } + else { + return ROBJECT_FIELDS_COUNT_NOT_COMPLEX(obj); + } +} + +static inline uint32_t +RBASIC_FIELDS_COUNT(VALUE obj) +{ + return RSHAPE(RBASIC_SHAPE_ID(obj))->next_field_index; +} + +static inline bool +rb_obj_shape_has_id(VALUE obj) +{ + return rb_shape_has_object_id(RBASIC_SHAPE_ID(obj)); +} + +static inline bool +rb_shape_has_ivars(shape_id_t shape_id) +{ + return shape_id & SHAPE_ID_HAS_IVAR_MASK; +} + +static inline bool +rb_obj_shape_has_ivars(VALUE obj) +{ + return rb_shape_has_ivars(RBASIC_SHAPE_ID(obj)); +} + +static inline bool +rb_shape_has_fields(shape_id_t shape_id) +{ + return shape_id & (SHAPE_ID_OFFSET_MASK | SHAPE_ID_FL_COMPLEX); +} + +static inline bool +rb_obj_shape_has_fields(VALUE obj) +{ + return rb_shape_has_fields(RBASIC_SHAPE_ID(obj)); +} + +static inline bool +rb_obj_gen_fields_p(VALUE obj) +{ + switch (TYPE(obj)) { + case T_NONE: + case T_OBJECT: + case T_CLASS: + case T_MODULE: + case T_IMEMO: + return false; + default: + break; + } + return rb_obj_shape_has_fields(obj); +} + +static inline bool +rb_obj_using_gen_fields_table_p(VALUE obj) +{ + switch (BUILTIN_TYPE(obj)) { + case T_DATA: + return false; + + case T_STRUCT: + if (!FL_TEST_RAW(obj, RSTRUCT_GEN_FIELDS)) return false; + break; + + default: + break; + } + + return rb_obj_gen_fields_p(obj); +} + +static inline shape_id_t +rb_shape_transition_frozen(shape_id_t shape_id) +{ + return shape_id | SHAPE_ID_FL_FROZEN; +} + +static inline shape_id_t +rb_shape_transition_complex(shape_id_t shape_id) +{ + shape_id_t next_shape_id = ROOT_COMPLEX_SHAPE_ID; + + if (rb_shape_has_object_id(shape_id)) { + next_shape_id = ROOT_COMPLEX_WITH_OBJ_ID; + } + + uint8_t heap_index = rb_shape_heap_index(shape_id); + if (heap_index) { + next_shape_id |= rb_shape_root(heap_index - 1); + } + + RUBY_ASSERT(rb_shape_has_object_id(shape_id) == rb_shape_has_object_id(next_shape_id)); + + return next_shape_id; +} + +static inline shape_id_t +rb_shape_transition_offset(shape_id_t shape_id, shape_id_t offset) +{ + offset = RSHAPE_OFFSET(offset); + RUBY_ASSERT(RSHAPE_OFFSET(shape_id) == offset || RSHAPE_DIRECT_CHILD_P(shape_id, offset)); + return RSHAPE_FLAGS(shape_id) | offset; +} + +static inline shape_id_t +rb_shape_transition_heap(shape_id_t shape_id, size_t heap_index) +{ + return (shape_id & (~SHAPE_ID_HEAP_INDEX_MASK)) | rb_shape_root(heap_index); +} + +shape_id_t rb_shape_transition_object_id(shape_id_t shape_id); + +static inline shape_id_t +rb_obj_shape_transition_frozen(VALUE obj) +{ + RUBY_ASSERT(RB_OBJ_FROZEN(obj)); + return rb_shape_transition_frozen(RBASIC_SHAPE_ID(obj)); +} + +static inline shape_id_t +rb_obj_shape_transition_complex(VALUE obj) +{ + return rb_shape_transition_complex(RBASIC_SHAPE_ID(obj)); +} + +static inline shape_id_t +rb_obj_shape_transition_heap(VALUE obj, size_t heap_index) +{ + return rb_shape_transition_heap(RBASIC_SHAPE_ID(obj), heap_index); +} + +static inline shape_id_t +rb_obj_shape_transition_object_id(VALUE obj) +{ + return rb_shape_transition_object_id(RBASIC_SHAPE_ID(obj)); +} + +shape_id_t rb_obj_shape_transition_remove_ivar(VALUE obj, ID id, shape_id_t *removed_shape_id); +shape_id_t rb_obj_shape_transition_add_ivar(VALUE obj, ID id); + +// For ext/objspace +RUBY_SYMBOL_EXPORT_BEGIN +typedef void each_shape_callback(shape_id_t shape_id, void *data); +void rb_shape_each_shape_id(each_shape_callback callback, void *data); +size_t rb_shape_memsize(shape_id_t shape); +size_t rb_shape_edges_count(shape_id_t shape_id); +size_t rb_shape_depth(shape_id_t shape_id); +RUBY_SYMBOL_EXPORT_END + +// Inline cache helpers + +typedef struct { + attr_index_t index; + shape_id_t shape_offset; +} rb_getivar_cache; + +union rb_getivar_cache { + uint64_t pack; + rb_getivar_cache unpack; +}; +STATIC_ASSERT(rb_getivar_cache_size, sizeof(union rb_getivar_cache) <= sizeof(uint64_t)); + +#define IVAR_CACHE_INIT ((uint64_t)-1) +#define ATTR_INDEX_T_NUM_BITS (sizeof(attr_index_t) * CHAR_BIT) + +static inline rb_getivar_cache +rb_getivar_cache_unpack(uint64_t packed) +{ + union rb_getivar_cache cache = { + .pack = packed, + }; + + // Because caches may initialized with all bits set (IVAR_CACHE_INIT), and `shape_offset` if 32bits, + // we need to remove any potential extra bits set in the "padding". + cache.unpack.shape_offset &= SHAPE_ID_OFFSET_MASK; + return cache.unpack; +} + +static inline uint64_t +rb_getivar_cache_pack(shape_id_t shape_offset, attr_index_t index) +{ + RUBY_ASSERT(shape_offset == RSHAPE_OFFSET(shape_offset)); + RUBY_ASSERT(shape_offset != INVALID_SHAPE_ID); + + union rb_getivar_cache cache = { + .unpack = { + .shape_offset = shape_offset, + .index = index, + }, + }; + return cache.pack; +} + +typedef struct { + attr_index_t index; + shape_id_t source_shape_offset; + shape_id_t dest_shape_offset; +} rb_setivar_cache; + +static inline rb_setivar_cache +rb_setivar_cache_unpack(uint64_t packed) +{ + rb_setivar_cache cache = { + .index = (attr_index_t)packed, + .source_shape_offset = RSHAPE_OFFSET((shape_id_t)(packed >> ATTR_INDEX_T_NUM_BITS)), + .dest_shape_offset = RSHAPE_OFFSET((shape_id_t)(packed >> (ATTR_INDEX_T_NUM_BITS + SHAPE_ID_OFFSET_NUM_BITS))), + }; + return cache; +} + +static inline uint64_t +rb_setivar_cache_pack(shape_id_t shape_offset, shape_id_t dest_shape_offset, attr_index_t index) +{ + RUBY_ASSERT(shape_offset == RSHAPE_OFFSET(shape_offset)); + RUBY_ASSERT(dest_shape_offset == RSHAPE_OFFSET(dest_shape_offset)); + RUBY_ASSERT(shape_offset == dest_shape_offset || RSHAPE_DIRECT_CHILD_P(shape_offset, dest_shape_offset)); + + uint64_t packed_cache = (uint64_t)dest_shape_offset << (ATTR_INDEX_T_NUM_BITS + SHAPE_ID_OFFSET_NUM_BITS); + packed_cache |= (uint64_t)shape_offset << ATTR_INDEX_T_NUM_BITS; + packed_cache |= (uint64_t)index; + return packed_cache; +} + + +ALWAYS_INLINE(static shape_id_t rb_setivar_cache_revalidate(shape_id_t shape_id, rb_setivar_cache cache)); +static shape_id_t +rb_setivar_cache_revalidate(shape_id_t shape_id, rb_setivar_cache cache) +{ + RUBY_ASSERT(shape_id != INVALID_SHAPE_ID); + RUBY_ASSERT(cache.dest_shape_offset == INVALID_SHAPE_ID || cache.dest_shape_offset == RSHAPE_OFFSET(cache.dest_shape_offset)); + + shape_id_t normalized_shape_id = shape_id & SHAPE_ID_WRITE_MASK; + if (UNLIKELY(normalized_shape_id != cache.source_shape_offset)) { + return INVALID_SHAPE_ID; + } + + if (UNLIKELY(cache.index >= RSHAPE_CAPACITY(shape_id))) { + // That's still a hit in term of layout, but the object will need to be resized, + // so unfortunately we'll have to go through the slow path regardless... + return INVALID_SHAPE_ID; + } + + // Cache hit case + RUBY_ASSERT(cache.source_shape_offset == cache.dest_shape_offset || RSHAPE_DIRECT_CHILD_P(shape_id, cache.dest_shape_offset)); + RUBY_ASSERT(cache.index < RSHAPE_CAPACITY(shape_id)); + RUBY_ASSERT(!rb_shape_frozen_p(shape_id)); + RUBY_ASSERT(!rb_shape_complex_p(shape_id)); + + // We use the cached offset, but combined with the current shape flags. + return rb_shape_transition_offset(shape_id, cache.dest_shape_offset); +} + +#endif |