81 lines
2.7 KiB
Rust
81 lines
2.7 KiB
Rust
//! Validates the MIR to ensure that invariants are upheld.
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use super::{MirPass, MirSource};
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use rustc_middle::mir::visit::Visitor;
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use rustc_middle::{
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mir::{Body, Location, Operand, Rvalue, Statement, StatementKind},
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ty::{ParamEnv, TyCtxt},
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};
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use rustc_span::{def_id::DefId, Span, DUMMY_SP};
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pub struct Validator {
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/// Describes at which point in the pipeline this validation is happening.
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pub when: String,
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}
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impl<'tcx> MirPass<'tcx> for Validator {
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fn run_pass(&self, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>) {
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let def_id = source.def_id();
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let param_env = tcx.param_env(def_id);
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TypeChecker { when: &self.when, def_id, body, tcx, param_env }.visit_body(body);
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}
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}
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struct TypeChecker<'a, 'tcx> {
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when: &'a str,
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def_id: DefId,
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body: &'a Body<'tcx>,
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tcx: TyCtxt<'tcx>,
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param_env: ParamEnv<'tcx>,
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}
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impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
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fn fail(&self, span: Span, msg: impl AsRef<str>) {
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// We use `delay_span_bug` as we might see broken MIR when other errors have already
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// occurred.
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self.tcx.sess.diagnostic().delay_span_bug(
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span,
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&format!("broken MIR in {:?} ({}): {}", self.def_id, self.when, msg.as_ref()),
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);
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
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fn visit_operand(&mut self, operand: &Operand<'tcx>, location: Location) {
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// `Operand::Copy` is only supposed to be used with `Copy` types.
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if let Operand::Copy(place) = operand {
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let ty = place.ty(&self.body.local_decls, self.tcx).ty;
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if !ty.is_copy_modulo_regions(self.tcx, self.param_env, DUMMY_SP) {
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self.fail(
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DUMMY_SP,
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format!("`Operand::Copy` with non-`Copy` type {} at {:?}", ty, location),
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);
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}
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}
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self.super_operand(operand, location);
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}
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fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
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// The sides of an assignment must not alias. Currently this just checks whether the places
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// are identical.
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if let StatementKind::Assign(box (dest, rvalue)) = &statement.kind {
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match rvalue {
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Rvalue::Use(Operand::Copy(src) | Operand::Move(src)) => {
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if dest == src {
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self.fail(
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DUMMY_SP,
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format!(
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"encountered `Assign` statement with overlapping memory at {:?}",
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location
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),
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);
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}
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}
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_ => {}
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}
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}
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}
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}
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