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Auto merge of #89572 - Manishearth:rollup-obz5ycp, r=Manishearth
Rollup of 10 pull requests Successful merges: - #88706 (Normalize associated type projections when checking return type of main) - #88828 (Use `libc::sigaction()` instead of `sys::signal()` to prevent a deadlock) - #88871 (Fix suggestion for nested struct patterns) - #89317 (Move generic error message to separate branches) - #89351 (for signed wrapping remainder, do not compare lhs with MIN) - #89442 (Add check for duplicated doc aliases) - #89502 (Fix Lower/UpperExp formatting for integers and precision zero) - #89523 (Make `proc_macro_derive_resolution_fallback` a future-breakage lint) - #89532 (Document behavior of `MaybeLiveLocals` regarding enums and field-senstivity) - #89546 (Make an initial guess for metadata size to reduce buffer resizes) Failed merges: r? `@ghost` `@rustbot` modify labels: rollup
2 parents 25ec827 + 5f8b161 commit 98a5a98

27 files changed

+455
-80
lines changed

‎compiler/rustc_lint_defs/src/builtin.rs

+1
Original file line numberDiff line numberDiff line change
@@ -1960,6 +1960,7 @@ declare_lint! {
19601960
"detects proc macro derives using inaccessible names from parent modules",
19611961
@future_incompatible = FutureIncompatibleInfo {
19621962
reference: "issue #83583 <https://github.com/rust-lang/rust/issues/83583>",
1963+
reason: FutureIncompatibilityReason::FutureReleaseErrorReportNow,
19631964
};
19641965
}
19651966

‎compiler/rustc_metadata/src/locator.rs

+3-1
Original file line numberDiff line numberDiff line change
@@ -740,7 +740,9 @@ fn get_metadata_section(
740740
// Header is okay -> inflate the actual metadata
741741
let compressed_bytes = &buf[header_len..];
742742
debug!("inflating {} bytes of compressed metadata", compressed_bytes.len());
743-
let mut inflated = Vec::new();
743+
// Assume the decompressed data will be at least the size of the compressed data, so we
744+
// don't have to grow the buffer as much.
745+
let mut inflated = Vec::with_capacity(compressed_bytes.len());
744746
match FrameDecoder::new(compressed_bytes).read_to_end(&mut inflated) {
745747
Ok(_) => rustc_erase_owner!(OwningRef::new(inflated).map_owner_box()),
746748
Err(_) => {

‎compiler/rustc_mir_dataflow/src/impls/liveness.rs

+31
Original file line numberDiff line numberDiff line change
@@ -11,6 +11,37 @@ use crate::{AnalysisDomain, Backward, GenKill, GenKillAnalysis};
1111
/// exist. See [this `mir-dataflow` test][flow-test] for an example. You almost never want to use
1212
/// this analysis without also looking at the results of [`MaybeBorrowedLocals`].
1313
///
14+
/// ## Field-(in)sensitivity
15+
///
16+
/// As the name suggests, this analysis is field insensitive. If a projection of a variable `x` is
17+
/// assigned to (e.g. `x.0 = 42`), it does not "define" `x` as far as liveness is concerned. In fact,
18+
/// such an assignment is currently marked as a "use" of `x` in an attempt to be maximally
19+
/// conservative.
20+
///
21+
/// ## Enums and `SetDiscriminant`
22+
///
23+
/// Assigning a literal value to an `enum` (e.g. `Option<i32>`), does not result in a simple
24+
/// assignment of the form `_1 = /*...*/` in the MIR. For example, the following assignment to `x`:
25+
///
26+
/// ```
27+
/// x = Some(4);
28+
/// ```
29+
///
30+
/// compiles to this MIR
31+
///
32+
/// ```
33+
/// ((_1 as Some).0: i32) = const 4_i32;
34+
/// discriminant(_1) = 1;
35+
/// ```
36+
///
37+
/// However, `MaybeLiveLocals` **does** mark `x` (`_1`) as "killed" after a statement like this.
38+
/// That's because it treats the `SetDiscriminant` operation as a definition of `x`, even though
39+
/// the writes that actually initialized the locals happened earlier.
40+
///
41+
/// This makes `MaybeLiveLocals` unsuitable for certain classes of optimization normally associated
42+
/// with a live variables analysis, notably dead-store elimination. It's a dirty hack, but it works
43+
/// okay for the generator state transform (currently the main consumuer of this analysis).
44+
///
1445
/// [`MaybeBorrowedLocals`]: super::MaybeBorrowedLocals
1546
/// [flow-test]: https://github.com/rust-lang/rust/blob/a08c47310c7d49cbdc5d7afb38408ba519967ecd/src/test/ui/mir-dataflow/liveness-ptr.rs
1647
/// [liveness]: https://en.wikipedia.org/wiki/Live_variable_analysis

‎compiler/rustc_passes/src/check_attr.rs

+36-6
Original file line numberDiff line numberDiff line change
@@ -9,7 +9,7 @@ use rustc_middle::ty::query::Providers;
99
use rustc_middle::ty::TyCtxt;
1010

1111
use rustc_ast::{ast, AttrStyle, Attribute, Lit, LitKind, NestedMetaItem};
12-
use rustc_data_structures::stable_set::FxHashSet;
12+
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
1313
use rustc_errors::{pluralize, struct_span_err, Applicability};
1414
use rustc_feature::{AttributeType, BUILTIN_ATTRIBUTE_MAP};
1515
use rustc_hir as hir;
@@ -66,6 +66,7 @@ impl CheckAttrVisitor<'tcx> {
6666
target: Target,
6767
item: Option<ItemLike<'_>>,
6868
) {
69+
let mut doc_aliases = FxHashMap::default();
6970
let mut is_valid = true;
7071
let mut specified_inline = None;
7172
let mut seen = FxHashSet::default();
@@ -79,7 +80,13 @@ impl CheckAttrVisitor<'tcx> {
7980
sym::track_caller => {
8081
self.check_track_caller(hir_id, &attr.span, attrs, span, target)
8182
}
82-
sym::doc => self.check_doc_attrs(attr, hir_id, target, &mut specified_inline),
83+
sym::doc => self.check_doc_attrs(
84+
attr,
85+
hir_id,
86+
target,
87+
&mut specified_inline,
88+
&mut doc_aliases,
89+
),
8390
sym::no_link => self.check_no_link(hir_id, &attr, span, target),
8491
sym::export_name => self.check_export_name(hir_id, &attr, span, target),
8592
sym::rustc_layout_scalar_valid_range_start
@@ -512,6 +519,7 @@ impl CheckAttrVisitor<'tcx> {
512519
hir_id: HirId,
513520
target: Target,
514521
is_list: bool,
522+
aliases: &mut FxHashMap<String, Span>,
515523
) -> bool {
516524
let tcx = self.tcx;
517525
let err_fn = move |span: Span, msg: &str| {
@@ -582,17 +590,38 @@ impl CheckAttrVisitor<'tcx> {
582590
if &*item_name.as_str() == doc_alias {
583591
return err_fn(meta.span(), "is the same as the item's name");
584592
}
593+
let span = meta.span();
594+
if let Err(entry) = aliases.try_insert(doc_alias.to_owned(), span) {
595+
self.tcx.struct_span_lint_hir(UNUSED_ATTRIBUTES, hir_id, span, |lint| {
596+
lint.build("doc alias is duplicated")
597+
.span_label(*entry.entry.get(), "first defined here")
598+
.emit();
599+
});
600+
}
585601
true
586602
}
587603

588-
fn check_doc_alias(&self, meta: &NestedMetaItem, hir_id: HirId, target: Target) -> bool {
604+
fn check_doc_alias(
605+
&self,
606+
meta: &NestedMetaItem,
607+
hir_id: HirId,
608+
target: Target,
609+
aliases: &mut FxHashMap<String, Span>,
610+
) -> bool {
589611
if let Some(values) = meta.meta_item_list() {
590612
let mut errors = 0;
591613
for v in values {
592614
match v.literal() {
593615
Some(l) => match l.kind {
594616
LitKind::Str(s, _) => {
595-
if !self.check_doc_alias_value(v, &s.as_str(), hir_id, target, true) {
617+
if !self.check_doc_alias_value(
618+
v,
619+
&s.as_str(),
620+
hir_id,
621+
target,
622+
true,
623+
aliases,
624+
) {
596625
errors += 1;
597626
}
598627
}
@@ -621,7 +650,7 @@ impl CheckAttrVisitor<'tcx> {
621650
}
622651
errors == 0
623652
} else if let Some(doc_alias) = meta.value_str().map(|s| s.to_string()) {
624-
self.check_doc_alias_value(meta, &doc_alias, hir_id, target, false)
653+
self.check_doc_alias_value(meta, &doc_alias, hir_id, target, false, aliases)
625654
} else {
626655
self.tcx
627656
.sess
@@ -858,6 +887,7 @@ impl CheckAttrVisitor<'tcx> {
858887
hir_id: HirId,
859888
target: Target,
860889
specified_inline: &mut Option<(bool, Span)>,
890+
aliases: &mut FxHashMap<String, Span>,
861891
) -> bool {
862892
let mut is_valid = true;
863893

@@ -867,7 +897,7 @@ impl CheckAttrVisitor<'tcx> {
867897
match i_meta.name_or_empty() {
868898
sym::alias
869899
if !self.check_attr_not_crate_level(&meta, hir_id, "alias")
870-
|| !self.check_doc_alias(&meta, hir_id, target) =>
900+
|| !self.check_doc_alias(&meta, hir_id, target, aliases) =>
871901
{
872902
is_valid = false
873903
}

‎compiler/rustc_passes/src/lib.rs

+2-1
Original file line numberDiff line numberDiff line change
@@ -9,8 +9,9 @@
99
#![feature(in_band_lifetimes)]
1010
#![feature(format_args_capture)]
1111
#![feature(iter_zip)]
12-
#![feature(nll)]
12+
#![feature(map_try_insert)]
1313
#![feature(min_specialization)]
14+
#![feature(nll)]
1415
#![feature(try_blocks)]
1516
#![recursion_limit = "256"]
1617

‎compiler/rustc_passes/src/liveness.rs

+15-8
Original file line numberDiff line numberDiff line change
@@ -265,21 +265,24 @@ impl IrMaps<'tcx> {
265265
self.capture_info_map.insert(hir_id, Rc::new(cs));
266266
}
267267

268-
fn add_from_pat(&mut self, pat: &hir::Pat<'tcx>) {
268+
fn collect_shorthand_field_ids(&self, pat: &hir::Pat<'tcx>) -> HirIdSet {
269269
// For struct patterns, take note of which fields used shorthand
270270
// (`x` rather than `x: x`).
271271
let mut shorthand_field_ids = HirIdSet::default();
272272
let mut pats = VecDeque::new();
273273
pats.push_back(pat);
274+
274275
while let Some(pat) = pats.pop_front() {
275276
use rustc_hir::PatKind::*;
276277
match &pat.kind {
277278
Binding(.., inner_pat) => {
278279
pats.extend(inner_pat.iter());
279280
}
280281
Struct(_, fields, _) => {
281-
let ids = fields.iter().filter(|f| f.is_shorthand).map(|f| f.pat.hir_id);
282-
shorthand_field_ids.extend(ids);
282+
let (short, not_short): (Vec<&_>, Vec<&_>) =
283+
fields.iter().partition(|f| f.is_shorthand);
284+
shorthand_field_ids.extend(short.iter().map(|f| f.pat.hir_id));
285+
pats.extend(not_short.iter().map(|f| f.pat));
283286
}
284287
Ref(inner_pat, _) | Box(inner_pat) => {
285288
pats.push_back(inner_pat);
@@ -296,6 +299,12 @@ impl IrMaps<'tcx> {
296299
}
297300
}
298301

302+
return shorthand_field_ids;
303+
}
304+
305+
fn add_from_pat(&mut self, pat: &hir::Pat<'tcx>) {
306+
let shorthand_field_ids = self.collect_shorthand_field_ids(pat);
307+
299308
pat.each_binding(|_, hir_id, _, ident| {
300309
self.add_live_node_for_node(hir_id, VarDefNode(ident.span, hir_id));
301310
self.add_variable(Local(LocalInfo {
@@ -373,15 +382,13 @@ impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
373382
}
374383

375384
fn visit_param(&mut self, param: &'tcx hir::Param<'tcx>) {
385+
let shorthand_field_ids = self.collect_shorthand_field_ids(param.pat);
376386
param.pat.each_binding(|_bm, hir_id, _x, ident| {
377387
let var = match param.pat.kind {
378-
rustc_hir::PatKind::Struct(_, fields, _) => Local(LocalInfo {
388+
rustc_hir::PatKind::Struct(..) => Local(LocalInfo {
379389
id: hir_id,
380390
name: ident.name,
381-
is_shorthand: fields
382-
.iter()
383-
.find(|f| f.ident == ident)
384-
.map_or(false, |f| f.is_shorthand),
391+
is_shorthand: shorthand_field_ids.contains(&hir_id),
385392
}),
386393
_ => Param(hir_id, ident.name),
387394
};

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