bjoernager/rust
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rustc_interface: Add a new query pre_configure

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It partially expands crate attributes before the main expansion pass (without modifying the crate), and the produced preliminary crate attribute list is used for querying a few attributes that are required very early.

Crate-level cfg attributes are then expanded normally during the main expansion pass, like attributes on any other nodes.
This commit is contained in:
Vadim Petrochenkov 2023-03-14 16:53:04 +04:00
parent f26da39e04
commit aca1b1e0b3
12 changed files with 108 additions and 84 deletions
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40
compiler/rustc_expand/src/config.rs
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@ -24,7 +24,6 @@ use rustc_session::Session;
use rustc_span::edition::{Edition, ALL_EDITIONS};
use rustc_span::symbol::{sym, Symbol};
use rustc_span::{Span, DUMMY_SP};
use thin_vec::ThinVec;
/// A folder that strips out items that do not belong in the current configuration.
pub struct StripUnconfigured<'a> {
@ -37,7 +36,7 @@ pub struct StripUnconfigured<'a> {
pub lint_node_id: NodeId,
}
fn get_features(sess: &Session, krate_attrs: &[ast::Attribute]) -> Features {
pub fn features(sess: &Session, krate_attrs: &[Attribute]) -> Features {
fn feature_removed(sess: &Session, span: Span, reason: Option<&str>) {
sess.emit_err(FeatureRemoved {
span,
@ -191,33 +190,16 @@ fn get_features(sess: &Session, krate_attrs: &[ast::Attribute]) -> Features {
features
}
/// `cfg_attr`-process the crate's attributes and compute the crate's features.
pub fn features(sess: &Session, krate: &mut ast::Crate, lint_node_id: NodeId) -> Features {
let mut strip_unconfigured =
StripUnconfigured { sess, features: None, config_tokens: false, lint_node_id };
let mut unconfigured_attrs = krate.attrs.clone();
let diag = &sess.parse_sess.span_diagnostic;
let err_count = diag.err_count();
krate.attrs.flat_map_in_place(|attr| strip_unconfigured.process_cfg_attr(&attr));
if !strip_unconfigured.in_cfg(&krate.attrs) {
// The entire crate is unconfigured.
krate.attrs = ast::AttrVec::new();
krate.items = ThinVec::new();
Features::default()
} else {
let features = get_features(sess, &krate.attrs);
if err_count == diag.err_count() {
// Avoid reconfiguring malformed `cfg_attr`s.
strip_unconfigured.features = Some(&features);
// Run configuration again, this time with features available
// so that we can perform feature-gating.
unconfigured_attrs.flat_map_in_place(|attr| strip_unconfigured.process_cfg_attr(&attr));
strip_unconfigured.in_cfg(&unconfigured_attrs);
}
features
}
pub fn pre_configure_attrs(sess: &Session, attrs: &[Attribute]) -> ast::AttrVec {
let strip_unconfigured = StripUnconfigured {
sess,
features: None,
config_tokens: false,
lint_node_id: ast::CRATE_NODE_ID,
};
let attrs: ast::AttrVec =
attrs.iter().flat_map(|attr| strip_unconfigured.process_cfg_attr(attr)).collect();
if strip_unconfigured.in_cfg(&attrs) { attrs } else { ast::AttrVec::new() }
}
#[macro_export]