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vm_getivar: normalize shape_id to ignore frozen state

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Freezing an object changes its `shape_id` This is necessary
so that `setivar` routines can use the `shape_id` as a cache key
and save on checking the frozen status every time.

However for `getivar` routines, this causes needless cache misses.
By clearing that bit we increase hit rate in codepaths that see
both frozen and mutable objects.
This commit is contained in:
Jean Boussier 2025-05-28 09:34:37 +02:00
parent 625d6a9cbb
commit bbd5a5a81d
Notes: git 2025-06-04 05:59:36 +00:00 
Merged: https://github.com/ruby/ruby/pull/13289
2 changed files with 10 additions and 2 deletions
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9
shape.h
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@ -14,6 +14,7 @@ STATIC_ASSERT(shape_id_num_bits, SHAPE_ID_NUM_BITS == sizeof(shape_id_t) * CHAR_
#define SHAPE_ID_OFFSET_MASK (SHAPE_BUFFER_SIZE - 1) #define SHAPE_ID_OFFSET_MASK (SHAPE_BUFFER_SIZE - 1)
#define SHAPE_ID_FLAGS_MASK (shape_id_t)(((1 << (SHAPE_ID_NUM_BITS - SHAPE_ID_OFFSET_NUM_BITS)) - 1) << SHAPE_ID_OFFSET_NUM_BITS) #define SHAPE_ID_FLAGS_MASK (shape_id_t)(((1 << (SHAPE_ID_NUM_BITS - SHAPE_ID_OFFSET_NUM_BITS)) - 1) << SHAPE_ID_OFFSET_NUM_BITS)
#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_READ_ONLY_MASK (~SHAPE_ID_FL_FROZEN)
typedef uint32_t redblack_id_t; typedef uint32_t redblack_id_t;
@ -110,6 +111,14 @@ RBASIC_SHAPE_ID(VALUE obj)
#endif #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;
}
static inline void static inline void
RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id) RBASIC_SET_SHAPE_ID(VALUE obj, shape_id_t shape_id)
{ {

3
vm_insnhelper.c
View File

@ -1215,14 +1215,13 @@ vm_getivar(VALUE obj, ID id, const rb_iseq_t *iseq, IVC ic, const struct rb_call
{ {
#if OPT_IC_FOR_IVAR #if OPT_IC_FOR_IVAR
VALUE val = Qundef; VALUE val = Qundef;
shape_id_t shape_id;
VALUE * ivar_list; VALUE * ivar_list;
if (SPECIAL_CONST_P(obj)) { if (SPECIAL_CONST_P(obj)) {
return default_value; return default_value;
} }
shape_id = RBASIC_SHAPE_ID(obj); shape_id_t shape_id = RBASIC_SHAPE_ID_FOR_READ(obj);
switch (BUILTIN_TYPE(obj)) { switch (BUILTIN_TYPE(obj)) {
case T_OBJECT: case T_OBJECT: