-use crate::utils::{
- fn_has_unsatisfiable_preds, has_drop, is_copy, is_type_diagnostic_item, match_def_path, match_type, paths,
- snippet_opt, span_lint_hir, span_lint_hir_and_then, walk_ptrs_ty_depth,
-};
+use clippy_utils::diagnostics::{span_lint_hir, span_lint_hir_and_then};
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::{has_drop, is_copy, is_type_diagnostic_item, walk_ptrs_ty_depth};
+use clippy_utils::{fn_has_unsatisfiable_preds, match_def_path, paths};
use if_chain::if_chain;
-use rustc_data_structures::{fx::FxHashMap, transitive_relation::TransitiveRelation};
+use rustc_data_structures::fx::FxHashMap;
use rustc_errors::Applicability;
use rustc_hir::intravisit::FnKind;
use rustc_hir::{def_id, Body, FnDecl, HirId};
use rustc_middle::mir::{
self, traversal,
visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor as _},
+ Mutability,
};
-use rustc_middle::ty::{self, fold::TypeVisitor, Ty};
-use rustc_mir::dataflow::BottomValue;
-use rustc_mir::dataflow::{Analysis, AnalysisDomain, GenKill, GenKillAnalysis, ResultsCursor};
+use rustc_middle::ty::{self, visit::TypeVisitor, Ty};
+use rustc_mir_dataflow::{Analysis, AnalysisDomain, CallReturnPlaces, GenKill, GenKillAnalysis, ResultsCursor};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::{BytePos, Span};
-use std::convert::TryFrom;
+use rustc_span::sym;
+use std::ops::ControlFlow;
macro_rules! unwrap_or_continue {
($x:expr) => {
}
declare_clippy_lint! {
- /// **What it does:** Checks for a redundant `clone()` (and its relatives) which clones an owned
+ /// ### What it does
+ /// Checks for a redundant `clone()` (and its relatives) which clones an owned
/// value that is going to be dropped without further use.
///
- /// **Why is this bad?** It is not always possible for the compiler to eliminate useless
+ /// ### Why is this bad?
+ /// It is not always possible for the compiler to eliminate useless
/// allocations and deallocations generated by redundant `clone()`s.
///
- /// **Known problems:**
- ///
+ /// ### Known problems
/// False-negatives: analysis performed by this lint is conservative and limited.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # use std::path::Path;
/// # #[derive(Clone)]
///
/// Path::new("/a/b").join("c").to_path_buf();
/// ```
+ #[clippy::version = "1.32.0"]
pub REDUNDANT_CLONE,
perf,
"`clone()` of an owned value that is going to be dropped immediately"
declare_lint_pass!(RedundantClone => [REDUNDANT_CLONE]);
impl<'tcx> LateLintPass<'tcx> for RedundantClone {
- #[allow(clippy::too_many_lines)]
+ #[expect(clippy::too_many_lines)]
fn check_fn(
&mut self,
cx: &LateContext<'tcx>,
let mir = cx.tcx.optimized_mir(def_id.to_def_id());
+ let possible_origin = {
+ let mut vis = PossibleOriginVisitor::new(mir);
+ vis.visit_body(mir);
+ vis.into_map(cx)
+ };
let maybe_storage_live_result = MaybeStorageLive
- .into_engine(cx.tcx, mir, def_id.to_def_id())
+ .into_engine(cx.tcx, mir)
+ .pass_name("redundant_clone")
.iterate_to_fixpoint()
.into_results_cursor(mir);
let mut possible_borrower = {
- let mut vis = PossibleBorrowerVisitor::new(cx, mir);
- vis.visit_body(&mir);
+ let mut vis = PossibleBorrowerVisitor::new(cx, mir, possible_origin);
+ vis.visit_body(mir);
vis.into_map(cx, maybe_storage_live_result)
};
}
// Give up on loops
- if terminator.successors().any(|s| *s == bb) {
+ if terminator.successors().any(|s| s == bb) {
continue;
}
let from_borrow = match_def_path(cx, fn_def_id, &paths::CLONE_TRAIT_METHOD)
|| match_def_path(cx, fn_def_id, &paths::TO_OWNED_METHOD)
|| (match_def_path(cx, fn_def_id, &paths::TO_STRING_METHOD)
- && is_type_diagnostic_item(cx, arg_ty, sym!(string_type)));
+ && is_type_diagnostic_item(cx, arg_ty, sym::String));
let from_deref = !from_borrow
&& (match_def_path(cx, fn_def_id, &paths::PATH_TO_PATH_BUF)
continue;
}
- // `{ cloned = &arg; clone(move cloned); }` or `{ cloned = &arg; to_path_buf(cloned); }`
+ if let ty::Adt(def, _) = arg_ty.kind() {
+ if def.is_manually_drop() {
+ continue;
+ }
+ }
+
+ // `{ arg = &cloned; clone(move arg); }` or `{ arg = &cloned; to_path_buf(arg); }`
let (cloned, cannot_move_out) = unwrap_or_continue!(find_stmt_assigns_to(cx, mir, arg, from_borrow, bb));
let loc = mir::Location {
// `arg` is a reference as it is `.deref()`ed in the previous block.
// Look into the predecessor block and find out the source of deref.
- let ps = &mir.predecessors()[bb];
+ let ps = &mir.basic_blocks.predecessors()[bb];
if ps.len() != 1 {
continue;
}
if let Some((pred_fn_def_id, pred_arg, pred_arg_ty, res)) =
is_call_with_ref_arg(cx, mir, &pred_terminator.kind);
if res == cloned;
- if match_def_path(cx, pred_fn_def_id, &paths::DEREF_TRAIT_METHOD);
- if match_type(cx, pred_arg_ty, &paths::PATH_BUF)
- || match_type(cx, pred_arg_ty, &paths::OS_STRING);
+ if cx.tcx.is_diagnostic_item(sym::deref_method, pred_fn_def_id);
+ if is_type_diagnostic_item(cx, pred_arg_ty, sym::PathBuf)
+ || is_type_diagnostic_item(cx, pred_arg_ty, sym::OsString);
then {
(pred_arg, res)
} else {
(local, deref_clone_ret)
};
- let is_temp = mir.local_kind(ret_local) == mir::LocalKind::Temp;
-
- // 1. `local` can be moved out if it is not used later.
- // 2. If `ret_local` is a temporary and is neither consumed nor mutated, we can remove this `clone`
- // call anyway.
- let (used, consumed_or_mutated) = traversal::ReversePostorder::new(&mir, bb).skip(1).fold(
- (false, !is_temp),
- |(used, consumed), (tbb, tdata)| {
- // Short-circuit
- if (used && consumed) ||
- // Give up on loops
- tdata.terminator().successors().any(|s| *s == bb)
- {
- return (true, true);
+ let clone_usage = if local == ret_local {
+ CloneUsage {
+ cloned_used: false,
+ cloned_consume_or_mutate_loc: None,
+ clone_consumed_or_mutated: true,
+ }
+ } else {
+ let clone_usage = visit_clone_usage(local, ret_local, mir, bb);
+ if clone_usage.cloned_used && clone_usage.clone_consumed_or_mutated {
+ // cloned value is used, and the clone is modified or moved
+ continue;
+ } else if let Some(loc) = clone_usage.cloned_consume_or_mutate_loc {
+ // cloned value is mutated, and the clone is alive.
+ if possible_borrower.local_is_alive_at(ret_local, loc) {
+ continue;
}
+ }
+ clone_usage
+ };
- let mut vis = LocalUseVisitor {
- used: (local, false),
- consumed_or_mutated: (ret_local, false),
- };
- vis.visit_basic_block_data(tbb, tdata);
- (used || vis.used.1, consumed || vis.consumed_or_mutated.1)
- },
- );
-
- if !used || !consumed_or_mutated {
- let span = terminator.source_info.span;
- let scope = terminator.source_info.scope;
- let node = mir.source_scopes[scope]
- .local_data
- .as_ref()
- .assert_crate_local()
- .lint_root;
-
- if_chain! {
- if let Some(snip) = snippet_opt(cx, span);
- if let Some(dot) = snip.rfind('.');
- then {
- let sugg_span = span.with_lo(
- span.lo() + BytePos(u32::try_from(dot).unwrap())
- );
- let mut app = Applicability::MaybeIncorrect;
-
- let mut call_snip = &snip[dot + 1..];
- // Machine applicable when `call_snip` looks like `foobar()`
- if call_snip.ends_with("()") {
- call_snip = call_snip[..call_snip.len()-2].trim();
- if call_snip.as_bytes().iter().all(|b| b.is_ascii_alphabetic() || *b == b'_') {
- app = Applicability::MachineApplicable;
- }
+ let span = terminator.source_info.span;
+ let scope = terminator.source_info.scope;
+ let node = mir.source_scopes[scope]
+ .local_data
+ .as_ref()
+ .assert_crate_local()
+ .lint_root;
+
+ if_chain! {
+ if let Some(snip) = snippet_opt(cx, span);
+ if let Some(dot) = snip.rfind('.');
+ then {
+ let sugg_span = span.with_lo(
+ span.lo() + BytePos(u32::try_from(dot).unwrap())
+ );
+ let mut app = Applicability::MaybeIncorrect;
+
+ let call_snip = &snip[dot + 1..];
+ // Machine applicable when `call_snip` looks like `foobar()`
+ if let Some(call_snip) = call_snip.strip_suffix("()").map(str::trim) {
+ if call_snip.as_bytes().iter().all(|b| b.is_ascii_alphabetic() || *b == b'_') {
+ app = Applicability::MachineApplicable;
}
+ }
- span_lint_hir_and_then(cx, REDUNDANT_CLONE, node, sugg_span, "redundant clone", |diag| {
- diag.span_suggestion(
- sugg_span,
- "remove this",
- String::new(),
- app,
+ span_lint_hir_and_then(cx, REDUNDANT_CLONE, node, sugg_span, "redundant clone", |diag| {
+ diag.span_suggestion(
+ sugg_span,
+ "remove this",
+ "",
+ app,
+ );
+ if clone_usage.cloned_used {
+ diag.span_note(
+ span,
+ "cloned value is neither consumed nor mutated",
);
- if used {
- diag.span_note(
- span,
- "cloned value is neither consumed nor mutated",
- );
- } else {
- diag.span_note(
- span.with_hi(span.lo() + BytePos(u32::try_from(dot).unwrap())),
- "this value is dropped without further use",
- );
- }
- });
- } else {
- span_lint_hir(cx, REDUNDANT_CLONE, node, span, "redundant clone");
- }
+ } else {
+ diag.span_note(
+ span.with_hi(span.lo() + BytePos(u32::try_from(dot).unwrap())),
+ "this value is dropped without further use",
+ );
+ }
+ });
+ } else {
+ span_lint_hir(cx, REDUNDANT_CLONE, node, span, "redundant clone");
}
}
}
if let mir::TerminatorKind::Call { func, args, destination, .. } = kind;
if args.len() == 1;
if let mir::Operand::Move(mir::Place { local, .. }) = &args[0];
- if let ty::FnDef(def_id, _) = func.ty(&*mir, cx.tcx).kind;
- if let (inner_ty, 1) = walk_ptrs_ty_depth(args[0].ty(&*mir, cx.tcx));
+ if let ty::FnDef(def_id, _) = *func.ty(mir, cx.tcx).kind();
+ if let (inner_ty, 1) = walk_ptrs_ty_depth(args[0].ty(mir, cx.tcx));
if !is_copy(cx, inner_ty);
then {
- Some((def_id, *local, inner_ty, destination.as_ref().map(|(dest, _)| dest)?.as_local()?))
+ Some((def_id, *local, inner_ty, destination.as_local()?))
} else {
None
}
None
})?;
- match (by_ref, &*rvalue) {
+ match (by_ref, rvalue) {
(true, mir::Rvalue::Ref(_, _, place)) | (false, mir::Rvalue::Use(mir::Operand::Copy(place))) => {
- base_local_and_movability(cx, mir, *place)
+ Some(base_local_and_movability(cx, mir, *place))
},
(false, mir::Rvalue::Ref(_, _, place)) => {
if let [mir::ProjectionElem::Deref] = place.as_ref().projection {
- base_local_and_movability(cx, mir, *place)
+ Some(base_local_and_movability(cx, mir, *place))
} else {
None
}
cx: &LateContext<'tcx>,
mir: &mir::Body<'tcx>,
place: mir::Place<'tcx>,
-) -> Option<(mir::Local, CannotMoveOut)> {
+) -> (mir::Local, CannotMoveOut) {
use rustc_middle::mir::PlaceRef;
// Dereference. You cannot move things out from a borrowed value.
&& !is_copy(cx, mir::Place::ty_from(local, projection, &mir.local_decls, cx.tcx).ty);
}
- Some((local, deref || field || slice))
+ (local, deref || field || slice)
}
-struct LocalUseVisitor {
- used: (mir::Local, bool),
- consumed_or_mutated: (mir::Local, bool),
+#[derive(Default)]
+struct CloneUsage {
+ /// Whether the cloned value is used after the clone.
+ cloned_used: bool,
+ /// The first location where the cloned value is consumed or mutated, if any.
+ cloned_consume_or_mutate_loc: Option<mir::Location>,
+ /// Whether the clone value is mutated.
+ clone_consumed_or_mutated: bool,
}
-
-impl<'tcx> mir::visit::Visitor<'tcx> for LocalUseVisitor {
- fn visit_basic_block_data(&mut self, block: mir::BasicBlock, data: &mir::BasicBlockData<'tcx>) {
- let statements = &data.statements;
- for (statement_index, statement) in statements.iter().enumerate() {
- self.visit_statement(statement, mir::Location { block, statement_index });
- }
-
- self.visit_terminator(
- data.terminator(),
- mir::Location {
- block,
- statement_index: statements.len(),
- },
- );
+fn visit_clone_usage(cloned: mir::Local, clone: mir::Local, mir: &mir::Body<'_>, bb: mir::BasicBlock) -> CloneUsage {
+ struct V {
+ cloned: mir::Local,
+ clone: mir::Local,
+ result: CloneUsage,
}
+ impl<'tcx> mir::visit::Visitor<'tcx> for V {
+ fn visit_basic_block_data(&mut self, block: mir::BasicBlock, data: &mir::BasicBlockData<'tcx>) {
+ let statements = &data.statements;
+ for (statement_index, statement) in statements.iter().enumerate() {
+ self.visit_statement(statement, mir::Location { block, statement_index });
+ }
- fn visit_place(&mut self, place: &mir::Place<'tcx>, ctx: PlaceContext, _: mir::Location) {
- let local = place.local;
-
- if local == self.used.0
- && !matches!(ctx, PlaceContext::MutatingUse(MutatingUseContext::Drop) | PlaceContext::NonUse(_))
- {
- self.used.1 = true;
+ self.visit_terminator(
+ data.terminator(),
+ mir::Location {
+ block,
+ statement_index: statements.len(),
+ },
+ );
}
- if local == self.consumed_or_mutated.0 {
- match ctx {
- PlaceContext::NonMutatingUse(NonMutatingUseContext::Move)
- | PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
- self.consumed_or_mutated.1 = true;
- },
- _ => {},
+ fn visit_place(&mut self, place: &mir::Place<'tcx>, ctx: PlaceContext, loc: mir::Location) {
+ let local = place.local;
+
+ if local == self.cloned
+ && !matches!(
+ ctx,
+ PlaceContext::MutatingUse(MutatingUseContext::Drop) | PlaceContext::NonUse(_)
+ )
+ {
+ self.result.cloned_used = true;
+ self.result.cloned_consume_or_mutate_loc = self.result.cloned_consume_or_mutate_loc.or_else(|| {
+ matches!(
+ ctx,
+ PlaceContext::NonMutatingUse(NonMutatingUseContext::Move)
+ | PlaceContext::MutatingUse(MutatingUseContext::Borrow)
+ )
+ .then(|| loc)
+ });
+ } else if local == self.clone {
+ match ctx {
+ PlaceContext::NonMutatingUse(NonMutatingUseContext::Move)
+ | PlaceContext::MutatingUse(MutatingUseContext::Borrow) => {
+ self.result.clone_consumed_or_mutated = true;
+ },
+ _ => {},
+ }
}
}
}
+
+ let init = CloneUsage {
+ cloned_used: false,
+ cloned_consume_or_mutate_loc: None,
+ // Consider non-temporary clones consumed.
+ // TODO: Actually check for mutation of non-temporaries.
+ clone_consumed_or_mutated: mir.local_kind(clone) != mir::LocalKind::Temp,
+ };
+ traversal::ReversePostorder::new(mir, bb)
+ .skip(1)
+ .fold(init, |usage, (tbb, tdata)| {
+ // Short-circuit
+ if (usage.cloned_used && usage.clone_consumed_or_mutated) ||
+ // Give up on loops
+ tdata.terminator().successors().any(|s| s == bb)
+ {
+ return CloneUsage {
+ cloned_used: true,
+ clone_consumed_or_mutated: true,
+ ..usage
+ };
+ }
+
+ let mut v = V {
+ cloned,
+ clone,
+ result: usage,
+ };
+ v.visit_basic_block_data(tbb, tdata);
+ v.result
+ })
}
/// Determines liveness of each local purely based on `StorageLive`/`Dead`.
struct MaybeStorageLive;
impl<'tcx> AnalysisDomain<'tcx> for MaybeStorageLive {
- type Idx = mir::Local;
+ type Domain = BitSet<mir::Local>;
const NAME: &'static str = "maybe_storage_live";
- fn bits_per_block(&self, body: &mir::Body<'tcx>) -> usize {
- body.local_decls.len()
+ fn bottom_value(&self, body: &mir::Body<'tcx>) -> Self::Domain {
+ // bottom = dead
+ BitSet::new_empty(body.local_decls.len())
}
- fn initialize_start_block(&self, body: &mir::Body<'tcx>, state: &mut BitSet<Self::Idx>) {
+ fn initialize_start_block(&self, body: &mir::Body<'tcx>, state: &mut Self::Domain) {
for arg in body.args_iter() {
state.insert(arg);
}
}
impl<'tcx> GenKillAnalysis<'tcx> for MaybeStorageLive {
+ type Idx = mir::Local;
+
fn statement_effect(&self, trans: &mut impl GenKill<Self::Idx>, stmt: &mir::Statement<'tcx>, _: mir::Location) {
match stmt.kind {
mir::StatementKind::StorageLive(l) => trans.gen(l),
fn call_return_effect(
&self,
- _in_out: &mut impl GenKill<Self::Idx>,
+ _trans: &mut impl GenKill<Self::Idx>,
_block: mir::BasicBlock,
- _func: &mir::Operand<'tcx>,
- _args: &[mir::Operand<'tcx>],
- _return_place: mir::Place<'tcx>,
+ _return_places: CallReturnPlaces<'_, 'tcx>,
) {
// Nothing to do when a call returns successfully
}
}
-impl BottomValue for MaybeStorageLive {
- /// bottom = dead
- const BOTTOM_VALUE: bool = false;
-}
-
/// Collects the possible borrowers of each local.
/// For example, `b = &a; c = &a;` will make `b` and (transitively) `c`
/// possible borrowers of `a`.
struct PossibleBorrowerVisitor<'a, 'tcx> {
- possible_borrower: TransitiveRelation<mir::Local>,
+ possible_borrower: TransitiveRelation,
body: &'a mir::Body<'tcx>,
cx: &'a LateContext<'tcx>,
+ possible_origin: FxHashMap<mir::Local, HybridBitSet<mir::Local>>,
}
impl<'a, 'tcx> PossibleBorrowerVisitor<'a, 'tcx> {
- fn new(cx: &'a LateContext<'tcx>, body: &'a mir::Body<'tcx>) -> Self {
+ fn new(
+ cx: &'a LateContext<'tcx>,
+ body: &'a mir::Body<'tcx>,
+ possible_origin: FxHashMap<mir::Local, HybridBitSet<mir::Local>>,
+ ) -> Self {
Self {
possible_borrower: TransitiveRelation::default(),
cx,
body,
+ possible_origin,
}
}
continue;
}
- let borrowers = self.possible_borrower.reachable_from(&row);
+ let mut borrowers = self.possible_borrower.reachable_from(row, self.body.local_decls.len());
+ borrowers.remove(mir::Local::from_usize(0));
if !borrowers.is_empty() {
- let mut bs = HybridBitSet::new_empty(self.body.local_decls.len());
- for &c in borrowers {
- if c != mir::Local::from_usize(0) {
- bs.insert(c);
- }
- }
-
- if !bs.is_empty() {
- map.insert(row, bs);
- }
+ map.insert(row, borrowers);
}
}
self.possible_borrower.add(borrowed.local, lhs);
},
other => {
- if !ContainsRegion.visit_ty(place.ty(&self.body.local_decls, self.cx.tcx).ty) {
+ if ContainsRegion
+ .visit_ty(place.ty(&self.body.local_decls, self.cx.tcx).ty)
+ .is_continue()
+ {
return;
}
rvalue_locals(other, |rhs| {
fn visit_terminator(&mut self, terminator: &mir::Terminator<'_>, _loc: mir::Location) {
if let mir::TerminatorKind::Call {
args,
- destination: Some((mir::Place { local: dest, .. }, _)),
+ destination: mir::Place { local: dest, .. },
..
} = &terminator.kind
{
+ // TODO add doc
// If the call returns something with lifetimes,
// let's conservatively assume the returned value contains lifetime of all the arguments.
// For example, given `let y: Foo<'a> = foo(x)`, `y` is considered to be a possible borrower of `x`.
- if !ContainsRegion.visit_ty(&self.body.local_decls[*dest].ty) {
- return;
- }
+
+ let mut immutable_borrowers = vec![];
+ let mut mutable_borrowers = vec![];
for op in args {
match op {
mir::Operand::Copy(p) | mir::Operand::Move(p) => {
- self.possible_borrower.add(p.local, *dest);
+ if let ty::Ref(_, _, Mutability::Mut) = self.body.local_decls[p.local].ty.kind() {
+ mutable_borrowers.push(p.local);
+ } else {
+ immutable_borrowers.push(p.local);
+ }
},
- _ => (),
+ mir::Operand::Constant(..) => (),
+ }
+ }
+
+ let mut mutable_variables: Vec<mir::Local> = mutable_borrowers
+ .iter()
+ .filter_map(|r| self.possible_origin.get(r))
+ .flat_map(HybridBitSet::iter)
+ .collect();
+
+ if ContainsRegion.visit_ty(self.body.local_decls[*dest].ty).is_break() {
+ mutable_variables.push(*dest);
+ }
+
+ for y in mutable_variables {
+ for x in &immutable_borrowers {
+ self.possible_borrower.add(*x, y);
+ }
+ for x in &mutable_borrowers {
+ self.possible_borrower.add(*x, y);
}
}
}
}
}
+/// Collect possible borrowed for every `&mut` local.
+/// For example, `_1 = &mut _2` generate _1: {_2,...}
+/// Known Problems: not sure all borrowed are tracked
+struct PossibleOriginVisitor<'a, 'tcx> {
+ possible_origin: TransitiveRelation,
+ body: &'a mir::Body<'tcx>,
+}
+
+impl<'a, 'tcx> PossibleOriginVisitor<'a, 'tcx> {
+ fn new(body: &'a mir::Body<'tcx>) -> Self {
+ Self {
+ possible_origin: TransitiveRelation::default(),
+ body,
+ }
+ }
+
+ fn into_map(self, cx: &LateContext<'tcx>) -> FxHashMap<mir::Local, HybridBitSet<mir::Local>> {
+ let mut map = FxHashMap::default();
+ for row in (1..self.body.local_decls.len()).map(mir::Local::from_usize) {
+ if is_copy(cx, self.body.local_decls[row].ty) {
+ continue;
+ }
+
+ let mut borrowers = self.possible_origin.reachable_from(row, self.body.local_decls.len());
+ borrowers.remove(mir::Local::from_usize(0));
+ if !borrowers.is_empty() {
+ map.insert(row, borrowers);
+ }
+ }
+ map
+ }
+}
+
+impl<'a, 'tcx> mir::visit::Visitor<'tcx> for PossibleOriginVisitor<'a, 'tcx> {
+ fn visit_assign(&mut self, place: &mir::Place<'tcx>, rvalue: &mir::Rvalue<'_>, _location: mir::Location) {
+ let lhs = place.local;
+ match rvalue {
+ // Only consider `&mut`, which can modify origin place
+ mir::Rvalue::Ref(_, rustc_middle::mir::BorrowKind::Mut { .. }, borrowed) |
+ // _2: &mut _;
+ // _3 = move _2
+ mir::Rvalue::Use(mir::Operand::Move(borrowed)) |
+ // _3 = move _2 as &mut _;
+ mir::Rvalue::Cast(_, mir::Operand::Move(borrowed), _)
+ => {
+ self.possible_origin.add(lhs, borrowed.local);
+ },
+ _ => {},
+ }
+ }
+}
+
struct ContainsRegion;
impl TypeVisitor<'_> for ContainsRegion {
- fn visit_region(&mut self, _: ty::Region<'_>) -> bool {
- true
+ type BreakTy = ();
+
+ fn visit_region(&mut self, _: ty::Region<'_>) -> ControlFlow<Self::BreakTy> {
+ ControlFlow::BREAK
}
}
let mut visit_op = |op: &mir::Operand<'_>| match op {
mir::Operand::Copy(p) | mir::Operand::Move(p) => visit(p.local),
- _ => (),
+ mir::Operand::Constant(..) => (),
};
match rvalue {
Use(op) | Repeat(op, _) | Cast(_, op, _) | UnaryOp(_, op) => visit_op(op),
Aggregate(_, ops) => ops.iter().for_each(visit_op),
- BinaryOp(_, lhs, rhs) | CheckedBinaryOp(_, lhs, rhs) => {
+ BinaryOp(_, box (lhs, rhs)) | CheckedBinaryOp(_, box (lhs, rhs)) => {
visit_op(lhs);
visit_op(rhs);
},
self.bitset.0 == self.bitset.1
}
+
+ fn local_is_alive_at(&mut self, local: mir::Local, at: mir::Location) -> bool {
+ self.maybe_live.seek_after_primary_effect(at);
+ self.maybe_live.contains(local)
+ }
+}
+
+#[derive(Default)]
+struct TransitiveRelation {
+ relations: FxHashMap<mir::Local, Vec<mir::Local>>,
+}
+impl TransitiveRelation {
+ fn add(&mut self, a: mir::Local, b: mir::Local) {
+ self.relations.entry(a).or_default().push(b);
+ }
+
+ fn reachable_from(&self, a: mir::Local, domain_size: usize) -> HybridBitSet<mir::Local> {
+ let mut seen = HybridBitSet::new_empty(domain_size);
+ let mut stack = vec![a];
+ while let Some(u) = stack.pop() {
+ if let Some(edges) = self.relations.get(&u) {
+ for &v in edges {
+ if seen.insert(v) {
+ stack.push(v);
+ }
+ }
+ }
+ }
+ seen
+ }
}
projects / rust.git / blobdiff