bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

Auto merge of #85885 - bjorn3:remove_box_region, r=cjgillot

Browse source 
Don't use a generator for BoxedResolver

The generator is non-trivial and requires unsafe code anyway. Using regular unsafe code without a generator is much easier to follow.

Based on #85810 as it touches rustc_interface too.
This commit is contained in:
bors 2021-06-11 16:11:20 +00:00
commit 0a8629bff6
6 changed files with 91 additions and 215 deletions
Download patch file Download diff file Expand all files Collapse all files

2
compiler/rustc_interface/src/lib.rs
View file

@ -2,8 +2,6 @@
#![feature(box_patterns)]
#![feature(internal_output_capture)]
#![feature(nll)]
#![feature(generator_trait)]
#![feature(generators)]
#![feature(once_cell)]
#![recursion_limit = "256"]

125
compiler/rustc_interface/src/passes.rs
View file

@ -6,10 +6,10 @@ use rustc_ast::mut_visit::MutVisitor;
use rustc_ast::{self as ast, visit};
use rustc_codegen_ssa::back::link::emit_metadata;
use rustc_codegen_ssa::traits::CodegenBackend;
use rustc_data_structures::parallel;
use rustc_data_structures::steal::Steal;
use rustc_data_structures::sync::{par_iter, Lrc, OnceCell, ParallelIterator, WorkerLocal};
use rustc_data_structures::temp_dir::MaybeTempDir;
use rustc_data_structures::{box_region_allow_access, declare_box_region_type, parallel};
use rustc_errors::{ErrorReported, PResult};
use rustc_expand::base::ExtCtxt;
use rustc_hir::def_id::LOCAL_CRATE;
@ -47,7 +47,9 @@ use std::cell::RefCell;
use std::ffi::OsString;
use std::io::{self, BufWriter, Write};
use std::lazy::SyncLazy;
use std::marker::PhantomPinned;
use std::path::PathBuf;
use std::pin::Pin;
use std::rc::Rc;
use std::{env, fs, iter};
@ -85,11 +87,83 @@ fn count_nodes(krate: &ast::Crate) -> usize {
counter.count
}
declare_box_region_type!(
pub BoxedResolver,
for(),
(&mut Resolver<'_>) -> (Result<ast::Crate>, ResolverOutputs)
);
pub use boxed_resolver::BoxedResolver;
mod boxed_resolver {
use super::*;
pub struct BoxedResolver(Pin<Box<BoxedResolverInner>>);
struct BoxedResolverInner {
session: Lrc<Session>,
resolver_arenas: Option<ResolverArenas<'static>>,
resolver: Option<Resolver<'static>>,
_pin: PhantomPinned,
}
// Note: Drop order is important to prevent dangling references. Resolver must be dropped first,
// then resolver_arenas and finally session.
impl Drop for BoxedResolverInner {
fn drop(&mut self) {
self.resolver.take();
self.resolver_arenas.take();
}
}
impl BoxedResolver {
pub(super) fn new<F>(session: Lrc<Session>, make_resolver: F) -> Result<(ast::Crate, Self)>
where
F: for<'a> FnOnce(
&'a Session,
&'a ResolverArenas<'a>,
) -> Result<(ast::Crate, Resolver<'a>)>,
{
let mut boxed_resolver = Box::new(BoxedResolverInner {
session,
resolver_arenas: Some(Resolver::arenas()),
resolver: None,
_pin: PhantomPinned,
});
// SAFETY: `make_resolver` takes a resolver arena with an arbitrary lifetime and
// returns a resolver with the same lifetime as the arena. We ensure that the arena
// outlives the resolver in the drop impl and elsewhere so these transmutes are sound.
unsafe {
let (crate_, resolver) = make_resolver(
std::mem::transmute::<&Session, &Session>(&boxed_resolver.session),
std::mem::transmute::<&ResolverArenas<'_>, &ResolverArenas<'_>>(
boxed_resolver.resolver_arenas.as_ref().unwrap(),
),
)?;
boxed_resolver.resolver = Some(resolver);
Ok((crate_, BoxedResolver(Pin::new_unchecked(boxed_resolver))))
}
}
pub fn access<F: for<'a> FnOnce(&mut Resolver<'a>) -> R, R>(&mut self, f: F) -> R {
// SAFETY: The resolver doesn't need to be pinned.
let mut resolver = unsafe {
self.0.as_mut().map_unchecked_mut(|boxed_resolver| &mut boxed_resolver.resolver)
};
f((&mut *resolver).as_mut().unwrap())
}
pub fn to_resolver_outputs(resolver: Rc<RefCell<BoxedResolver>>) -> ResolverOutputs {
match Rc::try_unwrap(resolver) {
Ok(resolver) => {
let mut resolver = resolver.into_inner();
// SAFETY: The resolver doesn't need to be pinned.
let mut resolver = unsafe {
resolver
.0
.as_mut()
.map_unchecked_mut(|boxed_resolver| &mut boxed_resolver.resolver)
};
resolver.take().unwrap().into_outputs()
}
Err(resolver) => resolver.borrow_mut().access(|resolver| resolver.clone_outputs()),
}
}
}
}
/// Runs the "early phases" of the compiler: initial `cfg` processing, loading compiler plugins,
/// syntax expansion, secondary `cfg` expansion, synthesis of a test
@ -111,41 +185,16 @@ pub fn configure_and_expand(
// its contents but the results of name resolution on those contents. Hopefully we'll push
// this back at some point.
let crate_name = crate_name.to_string();
let (result, resolver) = BoxedResolver::new(static move |mut action| {
let _ = action;
let sess = &*sess;
let resolver_arenas = Resolver::arenas();
let res = configure_and_expand_inner(
BoxedResolver::new(sess, move |sess, resolver_arenas| {
configure_and_expand_inner(
sess,
&lint_store,
krate,
&crate_name,
&resolver_arenas,
&*metadata_loader,
);
let mut resolver = match res {
Err(v) => {
yield BoxedResolver::initial_yield(Err(v));
panic!()
}
Ok((krate, resolver)) => {
action = yield BoxedResolver::initial_yield(Ok(krate));
resolver
}
};
box_region_allow_access!(for(), (&mut Resolver<'_>), (&mut resolver), action);
resolver.into_outputs()
});
result.map(|k| (k, resolver))
}
impl BoxedResolver {
pub fn to_resolver_outputs(resolver: Rc<RefCell<BoxedResolver>>) -> ResolverOutputs {
match Rc::try_unwrap(resolver) {
Ok(resolver) => resolver.into_inner().complete(),
Err(resolver) => resolver.borrow_mut().access(|resolver| resolver.clone_outputs()),
}
}
metadata_loader,
)
})
}
pub fn register_plugins<'a>(
@ -231,11 +280,11 @@ fn pre_expansion_lint(
fn configure_and_expand_inner<'a>(
sess: &'a Session,
lint_store: &'a LintStore,
lint_store: &LintStore,
mut krate: ast::Crate,
crate_name: &str,
resolver_arenas: &'a ResolverArenas<'a>,
metadata_loader: &'a MetadataLoaderDyn,
metadata_loader: Box<MetadataLoaderDyn>,
) -> Result<(ast::Crate, Resolver<'a>)> {
tracing::trace!("configure_and_expand_inner");
pre_expansion_lint(sess, lint_store, &krate, crate_name);