199 lines
6.2 KiB
Rust
199 lines
6.2 KiB
Rust
use crate as utils;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_hir as hir;
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use rustc_hir::def::Res;
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use rustc_hir::intravisit;
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use rustc_hir::intravisit::{NestedVisitorMap, Visitor};
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use rustc_hir::{Expr, ExprKind, HirId, Path};
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use rustc_infer::infer::TyCtxtInferExt;
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use rustc_lint::LateContext;
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use rustc_middle::hir::map::Map;
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use rustc_middle::ty;
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use rustc_typeck::expr_use_visitor::{ConsumeMode, Delegate, ExprUseVisitor, PlaceBase, PlaceWithHirId};
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/// Returns a set of mutated local variable IDs, or `None` if mutations could not be determined.
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pub fn mutated_variables<'tcx>(expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) -> Option<FxHashSet<HirId>> {
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let mut delegate = MutVarsDelegate {
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used_mutably: FxHashSet::default(),
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skip: false,
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};
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cx.tcx.infer_ctxt().enter(|infcx| {
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ExprUseVisitor::new(
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&mut delegate,
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&infcx,
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expr.hir_id.owner,
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cx.param_env,
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cx.typeck_results(),
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)
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.walk_expr(expr);
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});
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if delegate.skip {
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return None;
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}
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Some(delegate.used_mutably)
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}
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pub fn is_potentially_mutated<'tcx>(variable: &'tcx Path<'_>, expr: &'tcx Expr<'_>, cx: &LateContext<'tcx>) -> bool {
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if let Res::Local(id) = variable.res {
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mutated_variables(expr, cx).map_or(true, |mutated| mutated.contains(&id))
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} else {
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true
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}
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}
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struct MutVarsDelegate {
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used_mutably: FxHashSet<HirId>,
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skip: bool,
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}
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impl<'tcx> MutVarsDelegate {
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#[allow(clippy::similar_names)]
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fn update(&mut self, cat: &PlaceWithHirId<'tcx>) {
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match cat.place.base {
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PlaceBase::Local(id) => {
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self.used_mutably.insert(id);
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},
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PlaceBase::Upvar(_) => {
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//FIXME: This causes false negatives. We can't get the `NodeId` from
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//`Categorization::Upvar(_)`. So we search for any `Upvar`s in the
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//`while`-body, not just the ones in the condition.
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self.skip = true
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},
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_ => {},
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}
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}
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}
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impl<'tcx> Delegate<'tcx> for MutVarsDelegate {
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fn consume(&mut self, _: &PlaceWithHirId<'tcx>, _: HirId, _: ConsumeMode) {}
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fn borrow(&mut self, cmt: &PlaceWithHirId<'tcx>, _: HirId, bk: ty::BorrowKind) {
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if let ty::BorrowKind::MutBorrow = bk {
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self.update(&cmt)
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}
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}
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fn mutate(&mut self, cmt: &PlaceWithHirId<'tcx>, _: HirId) {
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self.update(&cmt)
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}
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}
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pub struct ParamBindingIdCollector {
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binding_hir_ids: Vec<hir::HirId>,
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}
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impl<'tcx> ParamBindingIdCollector {
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fn collect_binding_hir_ids(body: &'tcx hir::Body<'tcx>) -> Vec<hir::HirId> {
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let mut hir_ids: Vec<hir::HirId> = Vec::new();
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for param in body.params.iter() {
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let mut finder = ParamBindingIdCollector {
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binding_hir_ids: Vec::new(),
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};
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finder.visit_param(param);
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for hir_id in &finder.binding_hir_ids {
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hir_ids.push(*hir_id);
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}
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}
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hir_ids
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}
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}
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impl<'tcx> intravisit::Visitor<'tcx> for ParamBindingIdCollector {
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type Map = Map<'tcx>;
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fn visit_pat(&mut self, pat: &'tcx hir::Pat<'tcx>) {
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if let hir::PatKind::Binding(_, hir_id, ..) = pat.kind {
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self.binding_hir_ids.push(hir_id);
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}
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intravisit::walk_pat(self, pat);
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}
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fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
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intravisit::NestedVisitorMap::None
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}
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}
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pub struct BindingUsageFinder<'a, 'tcx> {
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cx: &'a LateContext<'tcx>,
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binding_ids: Vec<hir::HirId>,
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usage_found: bool,
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}
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impl<'a, 'tcx> BindingUsageFinder<'a, 'tcx> {
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pub fn are_params_used(cx: &'a LateContext<'tcx>, body: &'tcx hir::Body<'tcx>) -> bool {
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let mut finder = BindingUsageFinder {
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cx,
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binding_ids: ParamBindingIdCollector::collect_binding_hir_ids(body),
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usage_found: false,
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};
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finder.visit_body(body);
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finder.usage_found
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}
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}
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impl<'a, 'tcx> intravisit::Visitor<'tcx> for BindingUsageFinder<'a, 'tcx> {
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type Map = Map<'tcx>;
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fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
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if !self.usage_found {
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intravisit::walk_expr(self, expr);
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}
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}
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fn visit_path(&mut self, path: &'tcx hir::Path<'tcx>, _: hir::HirId) {
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if let hir::def::Res::Local(id) = path.res {
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if self.binding_ids.contains(&id) {
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self.usage_found = true;
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}
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}
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}
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fn nested_visit_map(&mut self) -> intravisit::NestedVisitorMap<Self::Map> {
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intravisit::NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
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}
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}
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struct ReturnBreakContinueMacroVisitor {
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seen_return_break_continue: bool,
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}
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impl ReturnBreakContinueMacroVisitor {
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fn new() -> ReturnBreakContinueMacroVisitor {
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ReturnBreakContinueMacroVisitor {
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seen_return_break_continue: false,
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}
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}
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}
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impl<'tcx> Visitor<'tcx> for ReturnBreakContinueMacroVisitor {
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type Map = Map<'tcx>;
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::None
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}
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fn visit_expr(&mut self, ex: &'tcx Expr<'tcx>) {
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if self.seen_return_break_continue {
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// No need to look farther if we've already seen one of them
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return;
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}
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match &ex.kind {
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ExprKind::Ret(..) | ExprKind::Break(..) | ExprKind::Continue(..) => {
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self.seen_return_break_continue = true;
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},
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// Something special could be done here to handle while or for loop
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// desugaring, as this will detect a break if there's a while loop
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// or a for loop inside the expression.
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_ => {
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if utils::in_macro(ex.span) {
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self.seen_return_break_continue = true;
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} else {
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rustc_hir::intravisit::walk_expr(self, ex);
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}
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},
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}
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}
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}
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pub fn contains_return_break_continue_macro(expression: &Expr<'_>) -> bool {
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let mut recursive_visitor = ReturnBreakContinueMacroVisitor::new();
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recursive_visitor.visit_expr(expression);
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recursive_visitor.seen_return_break_continue
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}
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