r? @nikomatsakis
Trying to land this first stab, which basically just duplicates the AST. Will file issues for the various things I've got in mind to improve.
this resolves type-variables early in assemble_candidates and
bails out quickly if the self type is an inference variable (which would
fail anyway because of `assemble_candidates_from_projected_tys`).
In both these cases, `assemble_candidates_from_impls` would try to go
over all impls and match them, leading to O(n*m) performance. Fixing this
improves rustc type-checking performance by 10%. As type-checking is only
is 5% of compilation, this doesn't impact bootstrap times, but *does*
improve type-error-detection time which is nice.
Crates that have many dependencies and contain significant amounts of
generic functions could see a bigger perf boost. As a microbenchmark,
the crate generated by
echo '#![feature(rustc_private)]'
echo 'extern crate rustc_driver;'
for i in {1..1000}; do cat << _EOF_
pub fn foo$i<T>() {
let mut v = Vec::new();
let _w = v.clone();
v.push("");
}
_EOF_
done
sees performance improve from 7.2 to 1.4 seconds. I imagine many crates
would fall somewhere in-between.
Running TLS destructors for a MSVC Windows binary requires the linker doesn't
elide the `_tls_used` or `__tls_used` symbols (depending on the architecture).
This is currently achieved via a `#[link_args]` hack but this only works for
dynamically linked binaries because the link arguments aren't propagated to
statically linked binaries.
This commit alters the strategy to instead emit a volatile load from those
symbols so LLVM can't elide it, forcing the reference to the symbol to stay
alive as long as the callback function stays alive (which we've made sure of
with the `#[linkage]` attribute).
Closes#28111
Running TLS destructors for a MSVC Windows binary requires the linker doesn't
elide the `_tls_used` or `__tls_used` symbols (depending on the architecture).
This is currently achieved via a `#[link_args]` hack but this only works for
dynamically linked binaries because the link arguments aren't propagated to
statically linked binaries.
This commit alters the strategy to instead emit a volatile load from those
symbols so LLVM can't elide it, forcing the reference to the symbol to stay
alive as long as the callback function stays alive (which we've made sure of
with the `#[linkage]` attribute).
Closes#28111
This changes a lot of `.to_string()` to `.to_owned()`, removes a few redundant closures, and changes some `match`es to `if let`s.
I'm currently in the process of trying out clippy and acting on its suggestions. I started with compiletest, because we use it to test clippy, too. If this finds positive reception, I may continue refactoring other parts of the rust codebase.
This is a [breaking-change] for syntax extension authors. The fix is to use MultiModifier or MultiDecorator, which have the same functionality but are more flexible. Users of syntax extensions are unaffected.
I believe everything that doesn't take a constant integer up to SSE4.2
should now be correct (I don't have any reason to believe that those
that do take constant integers are wrong; they're just more complicated
and I just haven't tested them in detail).
(Also, takes out two unused code paths from trans.)
I believe everything that doesn't take a constant integer up to SSE4.2
should now be correct (I don't have any reason to believe that those
that do take constant integers are wrong; they're just more complicated
and I just haven't tested them in detail).
This is a [breaking-change] for syntax extension authors. The fix is to use MultiModifier or MultiDecorator, which have the same functionality but are more flexible. Users of syntax extensions are unaffected.
