Replicate heap_index in shape_id flags.

This is preparation to getting rid of `T_OBJECT` transitions.
By first only replicating the information it's easier to ensure
consistency.
This commit is contained in:
Jean Boussier 2025-06-06 09:26:35 +02:00
parent 42cf301254
commit 689ec51146
Notes: git 2025-06-07 16:31:01 +00:00
4 changed files with 47 additions and 16 deletions

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@ -339,17 +339,15 @@ rb_obj_copy_ivar(VALUE dest, VALUE obj)
shape_id_t dest_shape_id = src_shape_id; shape_id_t dest_shape_id = src_shape_id;
shape_id_t initial_shape_id = RBASIC_SHAPE_ID(dest); shape_id_t initial_shape_id = RBASIC_SHAPE_ID(dest);
if (RSHAPE(initial_shape_id)->heap_index != RSHAPE(src_shape_id)->heap_index || !rb_shape_canonical_p(src_shape_id)) { RUBY_ASSERT(RSHAPE(initial_shape_id)->type == SHAPE_T_OBJECT);
RUBY_ASSERT(RSHAPE(initial_shape_id)->type == SHAPE_T_OBJECT);
dest_shape_id = rb_shape_rebuild(initial_shape_id, src_shape_id); dest_shape_id = rb_shape_rebuild(initial_shape_id, src_shape_id);
if (UNLIKELY(rb_shape_too_complex_p(dest_shape_id))) { if (UNLIKELY(rb_shape_too_complex_p(dest_shape_id))) {
st_table *table = rb_st_init_numtable_with_size(src_num_ivs); st_table *table = rb_st_init_numtable_with_size(src_num_ivs);
rb_obj_copy_ivs_to_hash_table(obj, table); rb_obj_copy_ivs_to_hash_table(obj, table);
rb_obj_init_too_complex(dest, table); rb_obj_init_too_complex(dest, table);
return; return;
}
} }
VALUE *src_buf = ROBJECT_FIELDS(obj); VALUE *src_buf = ROBJECT_FIELDS(obj);

19
shape.c
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@ -1092,7 +1092,10 @@ 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 *initial_shape = RSHAPE(initial_shape_id);
rb_shape_t *dest_shape = RSHAPE(dest_shape_id); rb_shape_t *dest_shape = RSHAPE(dest_shape_id);
return shape_id(shape_traverse_from_new_root(initial_shape, dest_shape), dest_shape_id);
// Keep all dest_shape_id flags except for the heap_index.
shape_id_t dest_flags = (dest_shape_id & ~SHAPE_ID_HEAP_INDEX_MASK) | (initial_shape_id & SHAPE_ID_HEAP_INDEX_MASK);
return shape_id(shape_traverse_from_new_root(initial_shape, dest_shape), dest_flags);
} }
// Rebuild a similar shape with the same ivars but starting from // Rebuild a similar shape with the same ivars but starting from
@ -1136,7 +1139,7 @@ rb_shape_rebuild(shape_id_t initial_shape_id, shape_id_t dest_shape_id)
RUBY_ASSERT(!rb_shape_too_complex_p(initial_shape_id)); RUBY_ASSERT(!rb_shape_too_complex_p(initial_shape_id));
RUBY_ASSERT(!rb_shape_too_complex_p(dest_shape_id)); RUBY_ASSERT(!rb_shape_too_complex_p(dest_shape_id));
return raw_shape_id(shape_rebuild(RSHAPE(initial_shape_id), RSHAPE(dest_shape_id))); return shape_id(shape_rebuild(RSHAPE(initial_shape_id), RSHAPE(dest_shape_id)), initial_shape_id);
} }
void void
@ -1238,6 +1241,14 @@ rb_shape_verify_consistency(VALUE obj, shape_id_t shape_id)
} }
} }
// All complex shape are in heap_index=0, it's a limitation
if (!rb_shape_too_complex_p(shape_id)) {
uint8_t flags_heap_index = rb_shape_heap_index(shape_id);
if (flags_heap_index != shape->heap_index) {
rb_bug("shape_id heap_index flags mismatch: flags=%u, transition=%u\n", flags_heap_index, shape->heap_index);
}
}
return true; return true;
} }
#endif #endif
@ -1288,6 +1299,7 @@ shape_id_t_to_rb_cShape(shape_id_t shape_id)
VALUE obj = rb_struct_new(rb_cShape, VALUE obj = rb_struct_new(rb_cShape,
INT2NUM(shape_id), INT2NUM(shape_id),
INT2NUM(shape_id & SHAPE_ID_OFFSET_MASK),
INT2NUM(shape->parent_id), INT2NUM(shape->parent_id),
rb_shape_edge_name(shape), rb_shape_edge_name(shape),
INT2NUM(shape->next_field_index), INT2NUM(shape->next_field_index),
@ -1528,7 +1540,7 @@ Init_default_shapes(void)
for (int i = 0; sizes[i] > 0; i++) { for (int i = 0; sizes[i] > 0; i++) {
rb_shape_t *t_object_shape = rb_shape_alloc_with_parent_id(0, INVALID_SHAPE_ID); rb_shape_t *t_object_shape = rb_shape_alloc_with_parent_id(0, INVALID_SHAPE_ID);
t_object_shape->type = SHAPE_T_OBJECT; t_object_shape->type = SHAPE_T_OBJECT;
t_object_shape->heap_index = i; t_object_shape->heap_index = i + 1;
t_object_shape->capacity = (uint32_t)((sizes[i] - offsetof(struct RObject, as.ary)) / sizeof(VALUE)); 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->edges = rb_managed_id_table_new(256);
t_object_shape->ancestor_index = LEAF; t_object_shape->ancestor_index = LEAF;
@ -1552,6 +1564,7 @@ Init_shape(void)
* :nodoc: */ * :nodoc: */
VALUE rb_cShape = rb_struct_define_under(rb_cRubyVM, "Shape", VALUE rb_cShape = rb_struct_define_under(rb_cRubyVM, "Shape",
"id", "id",
"raw_id",
"parent_id", "parent_id",
"edge_name", "edge_name",
"next_field_index", "next_field_index",

24
shape.h
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@ -16,8 +16,18 @@ STATIC_ASSERT(shape_id_num_bits, SHAPE_ID_NUM_BITS == sizeof(shape_id_t) * CHAR_
#define SHAPE_ID_FL_FROZEN (SHAPE_FL_FROZEN << SHAPE_ID_OFFSET_NUM_BITS) #define SHAPE_ID_FL_FROZEN (SHAPE_FL_FROZEN << SHAPE_ID_OFFSET_NUM_BITS)
#define SHAPE_ID_FL_HAS_OBJECT_ID (SHAPE_FL_HAS_OBJECT_ID << SHAPE_ID_OFFSET_NUM_BITS) #define SHAPE_ID_FL_HAS_OBJECT_ID (SHAPE_FL_HAS_OBJECT_ID << SHAPE_ID_OFFSET_NUM_BITS)
#define SHAPE_ID_FL_TOO_COMPLEX (SHAPE_FL_TOO_COMPLEX << SHAPE_ID_OFFSET_NUM_BITS) #define SHAPE_ID_FL_TOO_COMPLEX (SHAPE_FL_TOO_COMPLEX << SHAPE_ID_OFFSET_NUM_BITS)
#define SHAPE_ID_FL_EMBEDDED (SHAPE_FL_EMBEDDED << SHAPE_ID_OFFSET_NUM_BITS)
#define SHAPE_ID_FL_NON_CANONICAL_MASK (SHAPE_FL_NON_CANONICAL_MASK << SHAPE_ID_OFFSET_NUM_BITS) #define SHAPE_ID_FL_NON_CANONICAL_MASK (SHAPE_FL_NON_CANONICAL_MASK << SHAPE_ID_OFFSET_NUM_BITS)
#define SHAPE_ID_READ_ONLY_MASK (~SHAPE_ID_FL_FROZEN)
#define SHAPE_ID_HEAP_INDEX_BITS 3
#define SHAPE_ID_HEAP_INDEX_OFFSET (SHAPE_ID_NUM_BITS - SHAPE_ID_HEAP_INDEX_BITS)
#define SHAPE_ID_HEAP_INDEX_MAX ((1 << SHAPE_ID_HEAP_INDEX_BITS) - 1)
#define SHAPE_ID_HEAP_INDEX_MASK (SHAPE_ID_HEAP_INDEX_MAX << SHAPE_ID_HEAP_INDEX_OFFSET)
// The interpreter doesn't care about embeded or frozen status when reading ivars.
// So we normalize shape_id by clearing these bits to improve cache hits.
// JITs however might care about it.
#define SHAPE_ID_READ_ONLY_MASK (~(SHAPE_ID_FL_FROZEN | SHAPE_ID_FL_EMBEDDED | SHAPE_ID_HEAP_INDEX_MASK))
typedef uint32_t redblack_id_t; typedef uint32_t redblack_id_t;
@ -72,6 +82,7 @@ enum shape_flags {
SHAPE_FL_FROZEN = 1 << 0, SHAPE_FL_FROZEN = 1 << 0,
SHAPE_FL_HAS_OBJECT_ID = 1 << 1, SHAPE_FL_HAS_OBJECT_ID = 1 << 1,
SHAPE_FL_TOO_COMPLEX = 1 << 2, SHAPE_FL_TOO_COMPLEX = 1 << 2,
SHAPE_FL_EMBEDDED = 1 << 3,
SHAPE_FL_NON_CANONICAL_MASK = SHAPE_FL_FROZEN | SHAPE_FL_HAS_OBJECT_ID, SHAPE_FL_NON_CANONICAL_MASK = SHAPE_FL_FROZEN | SHAPE_FL_HAS_OBJECT_ID,
}; };
@ -189,10 +200,19 @@ rb_shape_canonical_p(shape_id_t shape_id)
return !(shape_id & SHAPE_ID_FL_NON_CANONICAL_MASK); 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 static inline shape_id_t
rb_shape_root(size_t heap_id) rb_shape_root(size_t heap_id)
{ {
return (shape_id_t)(heap_id + FIRST_T_OBJECT_SHAPE_ID); shape_id_t heap_index = (shape_id_t)heap_id;
shape_id_t shape_id = (heap_index + FIRST_T_OBJECT_SHAPE_ID);
return shape_id | ((heap_index + 1) << SHAPE_ID_HEAP_INDEX_OFFSET) | SHAPE_ID_FL_EMBEDDED;
} }
static inline bool static inline bool

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@ -976,7 +976,7 @@ class TestShapes < Test::Unit::TestCase
example.add_foo # makes a transition example.add_foo # makes a transition
add_foo_shape = RubyVM::Shape.of(example) add_foo_shape = RubyVM::Shape.of(example)
assert_equal([:@foo], example.instance_variables) assert_equal([:@foo], example.instance_variables)
assert_equal(initial_shape.id, add_foo_shape.parent.id) assert_equal(initial_shape.raw_id, add_foo_shape.parent.raw_id)
assert_equal(1, add_foo_shape.next_field_index) assert_equal(1, add_foo_shape.next_field_index)
example.remove_foo # makes a transition example.remove_foo # makes a transition
@ -987,7 +987,7 @@ class TestShapes < Test::Unit::TestCase
example.add_bar # makes a transition example.add_bar # makes a transition
bar_shape = RubyVM::Shape.of(example) bar_shape = RubyVM::Shape.of(example)
assert_equal([:@bar], example.instance_variables) assert_equal([:@bar], example.instance_variables)
assert_equal(initial_shape.id, bar_shape.parent_id) assert_equal(initial_shape.raw_id, bar_shape.parent_id)
assert_equal(1, bar_shape.next_field_index) assert_equal(1, bar_shape.next_field_index)
end end