Commits on Oct 2, 2023

1. Make TypedArena::alloc_from_iter like `DroplessArena::alloc_from_it… …

   …er`.
   
   `TypedArena` and `DroplessArena` both have an `alloc_from_impl` function, but
   they are implemented in completely different ways.
   
   - `TypedArena` uses the `IterExt` trait, which by default (a) collects the
     iterator's elements into a temporary `SmallVec`, (b) allocates memory, and
     (c) bulk-copies (and consumes) the elements into the arena memory. There are
     also specializations for `array::IntoIter`/`Vec`/`SmallVec` that
     avoid copying into a temporary `SmallVec`.
   
   - `DroplessArena` has two ways of doing it:
     - For known-sized iterators, it allocates memory and then copies items
       in one at a time.
    -  Otherwise, it works much like the default case for `TypedArena`, collecting
       into a temporary `SmallVec` and then bulk-copying.
   
   Performance-wise, they are very similar. `DroplessArena` is a little
   more general, because it automatically works with any known-sized
   iterator type, while `TypedArena`'s approach requires specialization on
   a per-type basis.
   
   This commit removes `IterExt` and moves
   `DroplessArena::{write,alloc}_from_iter` so they can be used from
   `TypedArena`. This reduces the amount of code in this file.

   

   nnethercote committed Oct 2, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for 56a99fa
   • Browse repository at this point

   Copy the full SHA

   56a99fa View commit details

   Browse the repository at this point in the history

2. Move TypedArena declaration next to its impls.

   

   nnethercote committed Oct 2, 2023
   Configuration menu

   • View commit details
   • Copy full SHA for 2c40e82
   • Browse repository at this point

   Copy the full SHA

   2c40e82 View commit details

   Browse the repository at this point in the history