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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:03:36 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-17 12:03:36 +0000
commit17d40c6057c88f4c432b0d7bac88e1b84cb7e67f (patch)
tree3f66c4a5918660bb8a758ab6cda5ff8ee4f6cdcd /compiler/rustc_passes/src/liveness.rs
parentAdding upstream version 1.64.0+dfsg1. (diff)
downloadrustc-upstream/1.65.0+dfsg1.tar.xz
rustc-upstream/1.65.0+dfsg1.zip
Adding upstream version 1.65.0+dfsg1.upstream/1.65.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'compiler/rustc_passes/src/liveness.rs')
-rw-r--r--compiler/rustc_passes/src/liveness.rs220
1 files changed, 151 insertions, 69 deletions
diff --git a/compiler/rustc_passes/src/liveness.rs b/compiler/rustc_passes/src/liveness.rs
index 461dd52b9..6a4cd79cd 100644
--- a/compiler/rustc_passes/src/liveness.rs
+++ b/compiler/rustc_passes/src/liveness.rs
@@ -89,16 +89,15 @@ use rustc_data_structures::fx::FxIndexMap;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::def::*;
-use rustc_hir::def_id::LocalDefId;
+use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::{self, Visitor};
use rustc_hir::{Expr, HirId, HirIdMap, HirIdSet};
use rustc_index::vec::IndexVec;
-use rustc_middle::hir::nested_filter;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::{self, DefIdTree, RootVariableMinCaptureList, Ty, TyCtxt};
use rustc_session::lint;
use rustc_span::symbol::{kw, sym, Symbol};
-use rustc_span::Span;
+use rustc_span::{BytePos, Span};
use std::collections::VecDeque;
use std::io;
@@ -139,12 +138,54 @@ fn live_node_kind_to_string(lnk: LiveNodeKind, tcx: TyCtxt<'_>) -> String {
}
}
-fn check_mod_liveness(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
- tcx.hir().visit_item_likes_in_module(module_def_id, &mut IrMaps::new(tcx));
+fn check_liveness(tcx: TyCtxt<'_>, def_id: DefId) {
+ let local_def_id = match def_id.as_local() {
+ None => return,
+ Some(def_id) => def_id,
+ };
+
+ // Don't run unused pass for #[derive()]
+ let parent = tcx.local_parent(local_def_id);
+ if let DefKind::Impl = tcx.def_kind(parent)
+ && tcx.has_attr(parent.to_def_id(), sym::automatically_derived)
+ {
+ return;
+ }
+
+ // Don't run unused pass for #[naked]
+ if tcx.has_attr(def_id, sym::naked) {
+ return;
+ }
+
+ let mut maps = IrMaps::new(tcx);
+ let body_id = tcx.hir().body_owned_by(local_def_id);
+ let hir_id = tcx.hir().body_owner(body_id);
+ let body = tcx.hir().body(body_id);
+
+ if let Some(upvars) = tcx.upvars_mentioned(def_id) {
+ for &var_hir_id in upvars.keys() {
+ let var_name = tcx.hir().name(var_hir_id);
+ maps.add_variable(Upvar(var_hir_id, var_name));
+ }
+ }
+
+ // gather up the various local variables, significant expressions,
+ // and so forth:
+ maps.visit_body(body);
+
+ // compute liveness
+ let mut lsets = Liveness::new(&mut maps, local_def_id);
+ let entry_ln = lsets.compute(&body, hir_id);
+ lsets.log_liveness(entry_ln, body_id.hir_id);
+
+ // check for various error conditions
+ lsets.visit_body(body);
+ lsets.warn_about_unused_upvars(entry_ln);
+ lsets.warn_about_unused_args(body, entry_ln);
}
pub fn provide(providers: &mut Providers) {
- *providers = Providers { check_mod_liveness, ..*providers };
+ *providers = Providers { check_liveness, ..*providers };
}
// ______________________________________________________________________
@@ -188,6 +229,19 @@ enum VarKind {
Upvar(HirId, Symbol),
}
+struct CollectLitsVisitor<'tcx> {
+ lit_exprs: Vec<&'tcx hir::Expr<'tcx>>,
+}
+
+impl<'tcx> Visitor<'tcx> for CollectLitsVisitor<'tcx> {
+ fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
+ if let hir::ExprKind::Lit(_) = expr.kind {
+ self.lit_exprs.push(expr);
+ }
+ intravisit::walk_expr(self, expr);
+ }
+}
+
struct IrMaps<'tcx> {
tcx: TyCtxt<'tcx>,
live_node_map: HirIdMap<LiveNode>,
@@ -316,56 +370,6 @@ impl<'tcx> IrMaps<'tcx> {
}
impl<'tcx> Visitor<'tcx> for IrMaps<'tcx> {
- type NestedFilter = nested_filter::OnlyBodies;
-
- fn nested_visit_map(&mut self) -> Self::Map {
- self.tcx.hir()
- }
-
- fn visit_body(&mut self, body: &'tcx hir::Body<'tcx>) {
- debug!("visit_body {:?}", body.id());
-
- // swap in a new set of IR maps for this body
- let mut maps = IrMaps::new(self.tcx);
- let hir_id = maps.tcx.hir().body_owner(body.id());
- let local_def_id = maps.tcx.hir().local_def_id(hir_id);
- let def_id = local_def_id.to_def_id();
-
- // Don't run unused pass for #[derive()]
- let parent = self.tcx.local_parent(local_def_id);
- if let DefKind::Impl = self.tcx.def_kind(parent)
- && self.tcx.has_attr(parent.to_def_id(), sym::automatically_derived)
- {
- return;
- }
-
- // Don't run unused pass for #[naked]
- if self.tcx.has_attr(def_id, sym::naked) {
- return;
- }
-
- if let Some(upvars) = maps.tcx.upvars_mentioned(def_id) {
- for &var_hir_id in upvars.keys() {
- let var_name = maps.tcx.hir().name(var_hir_id);
- maps.add_variable(Upvar(var_hir_id, var_name));
- }
- }
-
- // gather up the various local variables, significant expressions,
- // and so forth:
- intravisit::walk_body(&mut maps, body);
-
- // compute liveness
- let mut lsets = Liveness::new(&mut maps, local_def_id);
- let entry_ln = lsets.compute(&body, hir_id);
- lsets.log_liveness(entry_ln, body.id().hir_id);
-
- // check for various error conditions
- lsets.visit_body(body);
- lsets.warn_about_unused_upvars(entry_ln);
- lsets.warn_about_unused_args(body, entry_ln);
- }
-
fn visit_local(&mut self, local: &'tcx hir::Local<'tcx>) {
self.add_from_pat(&local.pat);
if local.els.is_some() {
@@ -1035,9 +1039,10 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
self.propagate_through_expr(&f, succ)
}
- hir::ExprKind::MethodCall(.., ref args, _) => {
+ hir::ExprKind::MethodCall(.., receiver, ref args, _) => {
let succ = self.check_is_ty_uninhabited(expr, succ);
- self.propagate_through_exprs(args, succ)
+ let succ = self.propagate_through_exprs(args, succ);
+ self.propagate_through_expr(receiver, succ)
}
hir::ExprKind::Tup(ref exprs) => self.propagate_through_exprs(exprs, succ),
@@ -1342,7 +1347,7 @@ impl<'a, 'tcx> Liveness<'a, 'tcx> {
impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
fn visit_local(&mut self, local: &'tcx hir::Local<'tcx>) {
- self.check_unused_vars_in_pat(&local.pat, None, |spans, hir_id, ln, var| {
+ self.check_unused_vars_in_pat(&local.pat, None, None, |spans, hir_id, ln, var| {
if local.init.is_some() {
self.warn_about_dead_assign(spans, hir_id, ln, var);
}
@@ -1357,7 +1362,7 @@ impl<'a, 'tcx> Visitor<'tcx> for Liveness<'a, 'tcx> {
}
fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
- self.check_unused_vars_in_pat(&arm.pat, None, |_, _, _, _| {});
+ self.check_unused_vars_in_pat(&arm.pat, None, None, |_, _, _, _| {});
intravisit::walk_arm(self, arm);
}
}
@@ -1396,7 +1401,7 @@ fn check_expr<'tcx>(this: &mut Liveness<'_, 'tcx>, expr: &'tcx Expr<'tcx>) {
}
hir::ExprKind::Let(let_expr) => {
- this.check_unused_vars_in_pat(let_expr.pat, None, |_, _, _, _| {});
+ this.check_unused_vars_in_pat(let_expr.pat, None, None, |_, _, _, _| {});
}
// no correctness conditions related to liveness
@@ -1517,13 +1522,18 @@ impl<'tcx> Liveness<'_, 'tcx> {
fn warn_about_unused_args(&self, body: &hir::Body<'_>, entry_ln: LiveNode) {
for p in body.params {
- self.check_unused_vars_in_pat(&p.pat, Some(entry_ln), |spans, hir_id, ln, var| {
- if !self.live_on_entry(ln, var) {
- self.report_unused_assign(hir_id, spans, var, |name| {
- format!("value passed to `{}` is never read", name)
- });
- }
- });
+ self.check_unused_vars_in_pat(
+ &p.pat,
+ Some(entry_ln),
+ Some(body),
+ |spans, hir_id, ln, var| {
+ if !self.live_on_entry(ln, var) {
+ self.report_unused_assign(hir_id, spans, var, |name| {
+ format!("value passed to `{}` is never read", name)
+ });
+ }
+ },
+ );
}
}
@@ -1531,6 +1541,7 @@ impl<'tcx> Liveness<'_, 'tcx> {
&self,
pat: &hir::Pat<'_>,
entry_ln: Option<LiveNode>,
+ opt_body: Option<&hir::Body<'_>>,
on_used_on_entry: impl Fn(Vec<Span>, HirId, LiveNode, Variable),
) {
// In an or-pattern, only consider the variable; any later patterns must have the same
@@ -1549,6 +1560,8 @@ impl<'tcx> Liveness<'_, 'tcx> {
.or_insert_with(|| (ln, var, vec![id_and_sp]));
});
+ let can_remove = matches!(&pat.kind, hir::PatKind::Struct(_, _, true));
+
for (_, (ln, var, hir_ids_and_spans)) in vars {
if self.used_on_entry(ln, var) {
let id = hir_ids_and_spans[0].0;
@@ -1556,16 +1569,20 @@ impl<'tcx> Liveness<'_, 'tcx> {
hir_ids_and_spans.into_iter().map(|(_, _, ident_span)| ident_span).collect();
on_used_on_entry(spans, id, ln, var);
} else {
- self.report_unused(hir_ids_and_spans, ln, var);
+ self.report_unused(hir_ids_and_spans, ln, var, can_remove, pat, opt_body);
}
}
}
+ #[instrument(skip(self), level = "INFO")]
fn report_unused(
&self,
hir_ids_and_spans: Vec<(HirId, Span, Span)>,
ln: LiveNode,
var: Variable,
+ can_remove: bool,
+ pat: &hir::Pat<'_>,
+ opt_body: Option<&hir::Body<'_>>,
) {
let first_hir_id = hir_ids_and_spans[0].0;
@@ -1590,6 +1607,32 @@ impl<'tcx> Liveness<'_, 'tcx> {
.emit();
},
)
+ } else if can_remove {
+ self.ir.tcx.struct_span_lint_hir(
+ lint::builtin::UNUSED_VARIABLES,
+ first_hir_id,
+ hir_ids_and_spans.iter().map(|(_, pat_span, _)| *pat_span).collect::<Vec<_>>(),
+ |lint| {
+ let mut err = lint.build(&format!("unused variable: `{}`", name));
+ err.multipart_suggestion(
+ "try removing the field",
+ hir_ids_and_spans
+ .iter()
+ .map(|(_, pat_span, _)| {
+ let span = self
+ .ir
+ .tcx
+ .sess
+ .source_map()
+ .span_extend_to_next_char(*pat_span, ',', true);
+ (span.with_hi(BytePos(span.hi().0 + 1)), String::new())
+ })
+ .collect(),
+ Applicability::MachineApplicable,
+ );
+ err.emit();
+ },
+ );
} else {
let (shorthands, non_shorthands): (Vec<_>, Vec<_>) =
hir_ids_and_spans.iter().copied().partition(|(hir_id, _, ident_span)| {
@@ -1643,6 +1686,9 @@ impl<'tcx> Liveness<'_, 'tcx> {
.collect::<Vec<_>>(),
|lint| {
let mut err = lint.build(&format!("unused variable: `{}`", name));
+ if self.has_added_lit_match_name_span(&name, opt_body, &mut err) {
+ err.span_label(pat.span, "unused variable");
+ }
err.multipart_suggestion(
"if this is intentional, prefix it with an underscore",
non_shorthands,
@@ -1656,6 +1702,42 @@ impl<'tcx> Liveness<'_, 'tcx> {
}
}
+ fn has_added_lit_match_name_span(
+ &self,
+ name: &str,
+ opt_body: Option<&hir::Body<'_>>,
+ err: &mut rustc_errors::DiagnosticBuilder<'_, ()>,
+ ) -> bool {
+ let mut has_litstring = false;
+ let Some(opt_body) = opt_body else {return false;};
+ let mut visitor = CollectLitsVisitor { lit_exprs: vec![] };
+ intravisit::walk_body(&mut visitor, opt_body);
+ for lit_expr in visitor.lit_exprs {
+ let hir::ExprKind::Lit(litx) = &lit_expr.kind else { continue };
+ let rustc_ast::LitKind::Str(syb, _) = litx.node else{ continue; };
+ let name_str: &str = syb.as_str();
+ let mut name_pa = String::from("{");
+ name_pa.push_str(&name);
+ name_pa.push('}');
+ if name_str.contains(&name_pa) {
+ err.span_label(
+ lit_expr.span,
+ "you might have meant to use string interpolation in this string literal",
+ );
+ err.multipart_suggestion(
+ "string interpolation only works in `format!` invocations",
+ vec![
+ (lit_expr.span.shrink_to_lo(), "format!(".to_string()),
+ (lit_expr.span.shrink_to_hi(), ")".to_string()),
+ ],
+ Applicability::MachineApplicable,
+ );
+ has_litstring = true;
+ }
+ }
+ has_litstring
+ }
+
fn warn_about_dead_assign(&self, spans: Vec<Span>, hir_id: HirId, ln: LiveNode, var: Variable) {
if !self.live_on_exit(ln, var) {
self.report_unused_assign(hir_id, spans, var, |name| {