Add shape_id to RBasic under 32 bit #13341
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jhawthorn force-pushed the shape_id_in_flags_32 branch from 96f185e to 9755585 Compare jhawthorn changed the title 
eregon reviewed May 21, 2025
include/ruby/internal/core/rbasic.h Outdated
| #if RBASIC_SHAPE_ID_FIELD | ||
| RBASIC(obj)->shape_id = 0; | ||
| #endif | ||
| } |
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Since this is added, how about adding RBASIC_FLAGS & RBASIC_SET_FLAGS as in truffleruby/truffleruby#3118 (comment) ?
That would help reduce the amount of direct accesses to that field, and could add extra asserts (e.g. catching some code trying to set the frozen flag directly), etc.
Should RBASIC_SET_FLAGS(obj, 0) reset the shape too?
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Why not, but there's currently too many raw accesses to the flags field, so if we do this I think it should be a standalone PR.
eregon reviewed May 21, 2025
byroot force-pushed the shape_id_in_flags_32 branch 3 times, most recently from 0f06ba1 to d4f6fa4 Compare 
This makes `RBobject` `4B` larger on 32 bit systems but simplifies the implementation a lot. [Feature #21353] Co-authored-by: Jean Boussier <byroot@ruby-lang.org>
byroot force-pushed the shape_id_in_flags_32 branch from d4f6fa4 to 1e552ba Compare casperisfine referenced this pull request Jun 2, 2025
We don't want the default GC to depend on Ruby internals so we can build it as a modular GC.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
casperisfine pushed a commit to Shopify/ruby that referenced this pull request Jun 3, 2025
Followup: ruby#13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
byroot added a commit that referenced this pull request Jun 3, 2025
Followup: #13341 / [Feature #21353] Even thought `shape_id_t` has been make 32bits, we were still limited to use only the lower 16 bits because they had to fit alongside `attr_index_t` inside a `uintptr_t` in inline caches. By enlarging inline caches we can unlock the full 32bits on all platforms, allowing to use these extra bits for tagging.
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[Feature #21353]
This adds a separate VALUE-sized shape_id field for 32-bit platforms. Allowing them to work much more similarly to how shapes always being available on 64-bit.
This does increase the size of objects by 4 bytes on 32 bit platforms, but shape access should be faster, more consistent, of the same size (32 bits) and much simpler.