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Remove LazyTokenStream
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#58476
Remove LazyTokenStream
.
#58476
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@bors try |
Remove `LazyTokenStream`. `LazyTokenStream` was added in #40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
☀️ Test successful - checks-travis |
I'm sorry for the amount of hacks you had to witness while doing this. |
Waiting on perf, otherwise r=me with nits addressed. |
@rust-timer build 25f58f3 |
Success: Queued 25f58f3 with parent f47ec2a, comparison URL. |
It reminds me of #57486 in which I removed |
Finished benchmarking try commit 25f58f3 |
The comparison URL shows a clear instructions and max-rss win for |
It is currently a method of `Token`, but it only is valid to call if `self` is a `Token::Interpolated`. This commit eliminates the possibility of misuse by changing it to an associated function that takes a `Nonterminal`, which also simplifies the call sites. This requires splitting out a new function, `nonterminal_to_string`.
It's present within `Token::Interpolated` as an optimization, so that if a nonterminal is converted to a `TokenStream` multiple times, the first-computed value is saved and reused. But in practice it's not needed. `interpolated_to_tokenstream()` is a cold function: it's only called a few dozen times while compiling rustc itself, and a few hundred times across the entire `rustc-perf` suite. Furthermore, when it is called, it is almost always the first conversion, so no benefit is gained from it. So this commit removes `LazyTokenStream`, along with the now-unnecessary `Token::interpolated()`. As well as a significant simplification, the removal speeds things up slightly, mostly due to not having to `drop` the `LazyTokenStream` instances.
The current code (expensively) clones the value within an `Rc`. This commit changes things so that the `Rc` itself is (cheaply) cloned instead, avoid some allocations. This requires converting a few `Rc` instances to `Lrc`.
These are probably leftovers from recent `TokenStream` simplifications.
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@petrochenkov: I've pushed two new commits, one to address your review comment, and another very simple clean-up. |
@bors r+ |
📌 Commit 895a794 has been approved by |
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
…etrochenkov Remove `LazyTokenStream`. `LazyTokenStream` was added in rust-lang#40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster. r? @alexcrichton
Rollup of 16 pull requests Successful merges: - #58100 (Transition librustdoc to Rust 2018) - #58122 (RangeInclusive internal iteration performance improvement.) - #58199 (Add better error message for partial move) - #58227 (Updated RELEASES.md for 1.33.0) - #58353 (Check the Self-type of inherent associated constants) - #58453 (SGX target: fix panic = abort) - #58476 (Remove `LazyTokenStream`.) - #58526 (Special suggestion for illegal unicode curly quote pairs) - #58595 (Turn duration consts into associated consts) - #58609 (Allow Self::Module to be mutated.) - #58628 (Optimise vec![false; N] to zero-alloc) - #58643 (Don't generate minification variables if minification disabled) - #58648 (Update tests to account for cross-platform testing and miri.) - #58654 (Do not underflow after resetting unmatched braces count) - #58658 (Add expected/provided byte alignments to validation error message) - #58667 (Reduce Miri-related Code Repetition `like (n << amt) >> amt`) Failed merges: r? @ghost
LazyTokenStream
was added in #40939. Perhaps it was an effective optimization then, but no longer. This PR removes it, making the code both simpler and faster.r? @alexcrichton