mirror of
https://github.com/ruby/ruby.git
synced 2025-08-23 21:14:23 +02:00
ef95e5ba3d
ZJIT uses the interpreter to take type profiles of what objects pass through the code. It stores a compressed record of the history per opcode for the opcodes we select. Before this change, we re-used the HIR Type data-structure, a shallow type lattice, to store historical type information. This was quick for bringup but is quite lossy as profiles go: we get one bit per built-in type seen, and if we see a non-built-in type in addition, we end up with BasicObject. Not very helpful. Additionally, it does not give us any notion of cardinality: how many of each type did we see? This change brings with it a much more interesting slice of type history: a histogram. A Distribution holds a record of the top-N (where N is fixed at Ruby compile-time) `(Class, ShapeId)` pairs and their counts. It also holds an *other* count in case we see more than N pairs. Using this distribution, we can make more informed decisions about when we should use type information. We can determine if we are strictly monomorphic, very nearly monomorphic, or something else. Maybe the call-site is polymorphic, so we should have a polymorphic inline cache. Exciting stuff. I also plumb this new distribution into the HIR part of the compilation pipeline. |
||
|---|---|---|
| .. | ||
| src | ||
| Cargo.lock | ||
| Cargo.toml | ||