Don't share id_map and deref_id_map
#82424
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...and remove `Rc`s for the moved fields. The only shared one that I didn't move was `cache`; see the doc-comment I added to `cache` for details.
It doesn't look like it's shared across threads, so it doesn't need to be thread-safe. Of course, since we're using Rust, we'll get an error if we try to share it across threads, so this should be safe :)
It's cloned a lot, so we don't want it to grow in size unexpectedly.
The size is architecture-dependent.
All the tests passed, so it doesn't seem they need to be shared. Plus they should be item/page-specific. I'm not sure why they were shared before. I think the reason `id_map` worked as a shared value before is that it is cleared before rendering each item (in `render_item`). And then I'm guessing `deref_id_map` worked because it's a hashmap keyed by `DefId`, so there was no overlap (though I'm guessing we could have had issues in the future). Note that `id_map` currently still has to be cleared because otherwise child items would inherit the `id_map` of their parent. I'm hoping to figure out a way to stop cloning `Context`, but until then we have to reset `id_map`.
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Only the last commit is new (the others will disappear once #82356 is merged and I rebase). |
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Feb 23, 2021
src/librustdoc/html/render/mod.rs
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| /// The map used to ensure all generated 'id=' attributes are unique. | ||
| id_map: RefCell<IdMap>, | ||
| /// Tracks section IDs for `Deref` targets so they match in both the main | ||
| /// body and the sidebar. | ||
| deref_id_map: RefCell<FxHashMap<DefId, String>>, |
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I wasn't able to get rid of the RefCells here because the fields are used all over the place.
src/librustdoc/html/render/mod.rs
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| rustc_data_structures::static_assert_size!(Context<'_>, 72); | ||
| rustc_data_structures::static_assert_size!(Context<'_>, 152); |
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Big size increase! Should I box the fields to reduce the size?
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Instead of using this new PR, should I just add this commit to #82356? It would reduce the churn of moving the fields back and forth. |
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Okay, will do. |
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Cherry-picked into #82356. Closing this PR now. |
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All the tests passed, so it doesn't seem they need to be shared.
Plus they should be item/page-specific.
I'm not sure why they were shared before. I think the reason
id_mapworked as a shared value before is that it is cleared before rendering
each item (in
render_item). And then I'm guessingderef_id_mapworked because it's a hashmap keyed by
DefId, so there was no overlap(though I'm guessing we could have had issues in the future).
Note that
id_mapcurrently still has to be cleared because otherwisechild items would inherit the
id_mapof their parent. I'm hoping tofigure out a way to stop cloning
Context, but until then we have toreset
id_map.Builds on top of #82356 (otherwise we'd have merge conflicts), so this is
blocked on that PR.