diff --git a/compiler/rustc_mir/src/transform/validate.rs b/compiler/rustc_mir/src/transform/validate.rs index d3ca14abdcab2..d1a91ae4fc33a 100644 --- a/compiler/rustc_mir/src/transform/validate.rs +++ b/compiler/rustc_mir/src/transform/validate.rs @@ -1,7 +1,12 @@ //! Validates the MIR to ensure that invariants are upheld. +use crate::{ + dataflow::impls::MaybeStorageLive, dataflow::Analysis, dataflow::ResultsCursor, + util::storage::AlwaysLiveLocals, +}; + use super::{MirPass, MirSource}; -use rustc_middle::mir::visit::Visitor; +use rustc_middle::mir::{visit::PlaceContext, visit::Visitor, Local}; use rustc_middle::{ mir::{ AggregateKind, BasicBlock, Body, BorrowKind, Location, MirPhase, Operand, Rvalue, @@ -33,9 +38,18 @@ pub struct Validator { impl<'tcx> MirPass<'tcx> for Validator { fn run_pass(&self, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>) { - let param_env = tcx.param_env(source.def_id()); + let def_id = source.def_id(); + let param_env = tcx.param_env(def_id); let mir_phase = self.mir_phase; - TypeChecker { when: &self.when, source, body, tcx, param_env, mir_phase }.visit_body(body); + + let always_live_locals = AlwaysLiveLocals::new(body); + let storage_liveness = MaybeStorageLive::new(always_live_locals) + .into_engine(tcx, body, def_id) + .iterate_to_fixpoint() + .into_results_cursor(body); + + TypeChecker { when: &self.when, source, body, tcx, param_env, mir_phase, storage_liveness } + .visit_body(body); } } @@ -138,6 +152,7 @@ struct TypeChecker<'a, 'tcx> { tcx: TyCtxt<'tcx>, param_env: ParamEnv<'tcx>, mir_phase: MirPhase, + storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive>, } impl<'a, 'tcx> TypeChecker<'a, 'tcx> { @@ -210,6 +225,17 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> { } impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { + fn visit_local(&mut self, local: &Local, context: PlaceContext, location: Location) { + if context.is_use() { + // Uses of locals must occur while the local's storage is allocated. + self.storage_liveness.seek_after_primary_effect(location); + let locals_with_storage = self.storage_liveness.get(); + if !locals_with_storage.contains(*local) { + self.fail(location, format!("use of local {:?}, which has no storage here", local)); + } + } + } + fn visit_operand(&mut self, operand: &Operand<'tcx>, location: Location) { // `Operand::Copy` is only supposed to be used with `Copy` types. if let Operand::Copy(place) = operand {