diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/transform/promote_consts.rs | 94 |
1 files changed, 52 insertions, 42 deletions
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs index 1052d588fad..f88538f61ec 100644 --- a/compiler/rustc_const_eval/src/transform/promote_consts.rs +++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs @@ -60,9 +60,9 @@ impl<'tcx> MirPass<'tcx> for PromoteTemps<'tcx> { let mut rpo = traversal::reverse_postorder(body); let ccx = ConstCx::new(tcx, body); - let (temps, all_candidates) = collect_temps_and_candidates(&ccx, &mut rpo); + let (mut temps, all_candidates) = collect_temps_and_candidates(&ccx, &mut rpo); - let promotable_candidates = validate_candidates(&ccx, &temps, &all_candidates); + let promotable_candidates = validate_candidates(&ccx, &mut temps, &all_candidates); let promoted = promote_candidates(body, tcx, temps, promotable_candidates); self.promoted_fragments.set(promoted); @@ -77,7 +77,7 @@ pub enum TempState { /// One direct assignment and any number of direct uses. /// A borrow of this temp is promotable if the assigned /// value is qualified as constant. - Defined { location: Location, uses: usize }, + Defined { location: Location, uses: usize, valid: Result<(), ()> }, /// Any other combination of assignments/uses. Unpromotable, /// This temp was part of an rvalue which got extracted @@ -133,7 +133,7 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> { match context { PlaceContext::MutatingUse(MutatingUseContext::Store) | PlaceContext::MutatingUse(MutatingUseContext::Call) => { - *temp = TempState::Defined { location, uses: 0 }; + *temp = TempState::Defined { location, uses: 0, valid: Err(()) }; return; } _ => { /* mark as unpromotable below */ } @@ -188,7 +188,7 @@ pub fn collect_temps_and_candidates<'tcx>( /// This wraps an `Item`, and has access to all fields of that `Item` via `Deref` coercion. struct Validator<'a, 'tcx> { ccx: &'a ConstCx<'a, 'tcx>, - temps: &'a IndexVec<Local, TempState>, + temps: &'a mut IndexVec<Local, TempState>, } impl<'a, 'tcx> std::ops::Deref for Validator<'a, 'tcx> { @@ -202,7 +202,7 @@ impl<'a, 'tcx> std::ops::Deref for Validator<'a, 'tcx> { struct Unpromotable; impl<'tcx> Validator<'_, 'tcx> { - fn validate_candidate(&self, candidate: Candidate) -> Result<(), Unpromotable> { + fn validate_candidate(&mut self, candidate: Candidate) -> Result<(), Unpromotable> { let loc = candidate.location; let statement = &self.body[loc.block].statements[loc.statement_index]; match &statement.kind { @@ -234,7 +234,7 @@ impl<'tcx> Validator<'_, 'tcx> { } // FIXME(eddyb) maybe cache this? - fn qualif_local<Q: qualifs::Qualif>(&self, local: Local) -> bool { + fn qualif_local<Q: qualifs::Qualif>(&mut self, local: Local) -> bool { if let TempState::Defined { location: loc, .. } = self.temps[local] { let num_stmts = self.body[loc.block].statements.len(); @@ -272,40 +272,50 @@ impl<'tcx> Validator<'_, 'tcx> { } } - // FIXME(eddyb) maybe cache this? - fn validate_local(&self, local: Local) -> Result<(), Unpromotable> { - if let TempState::Defined { location: loc, .. } = self.temps[local] { - let block = &self.body[loc.block]; - let num_stmts = block.statements.len(); - - if loc.statement_index < num_stmts { - let statement = &block.statements[loc.statement_index]; - match &statement.kind { - StatementKind::Assign(box (_, rhs)) => self.validate_rvalue(rhs), - _ => { - span_bug!( - statement.source_info.span, - "{:?} is not an assignment", - statement - ); - } - } - } else { - let terminator = block.terminator(); - match &terminator.kind { - TerminatorKind::Call { func, args, .. } => self.validate_call(func, args), - TerminatorKind::Yield { .. } => Err(Unpromotable), - kind => { - span_bug!(terminator.source_info.span, "{:?} not promotable", kind); + fn validate_local(&mut self, local: Local) -> Result<(), Unpromotable> { + if let TempState::Defined { location: loc, uses, valid } = self.temps[local] { + valid.or_else(|_| { + let ok = { + let block = &self.body[loc.block]; + let num_stmts = block.statements.len(); + + if loc.statement_index < num_stmts { + let statement = &block.statements[loc.statement_index]; + match &statement.kind { + StatementKind::Assign(box (_, rhs)) => self.validate_rvalue(rhs), + _ => { + span_bug!( + statement.source_info.span, + "{:?} is not an assignment", + statement + ); + } + } + } else { + let terminator = block.terminator(); + match &terminator.kind { + TerminatorKind::Call { func, args, .. } => { + self.validate_call(func, args) + } + TerminatorKind::Yield { .. } => Err(Unpromotable), + kind => { + span_bug!(terminator.source_info.span, "{:?} not promotable", kind); + } + } } - } - } + }; + self.temps[local] = match ok { + Ok(()) => TempState::Defined { location: loc, uses, valid: Ok(()) }, + Err(_) => TempState::Unpromotable, + }; + ok + }) } else { Err(Unpromotable) } } - fn validate_place(&self, place: PlaceRef<'tcx>) -> Result<(), Unpromotable> { + fn validate_place(&mut self, place: PlaceRef<'tcx>) -> Result<(), Unpromotable> { match place.last_projection() { None => self.validate_local(place.local), Some((place_base, elem)) => { @@ -417,7 +427,7 @@ impl<'tcx> Validator<'_, 'tcx> { } } - fn validate_operand(&self, operand: &Operand<'tcx>) -> Result<(), Unpromotable> { + fn validate_operand(&mut self, operand: &Operand<'tcx>) -> Result<(), Unpromotable> { match operand { Operand::Copy(place) | Operand::Move(place) => self.validate_place(place.as_ref()), @@ -447,7 +457,7 @@ impl<'tcx> Validator<'_, 'tcx> { } } - fn validate_ref(&self, kind: BorrowKind, place: &Place<'tcx>) -> Result<(), Unpromotable> { + fn validate_ref(&mut self, kind: BorrowKind, place: &Place<'tcx>) -> Result<(), Unpromotable> { match kind { // Reject these borrow types just to be safe. // FIXME(RalfJung): could we allow them? Should we? No point in it until we have a usecase. @@ -480,7 +490,7 @@ impl<'tcx> Validator<'_, 'tcx> { Ok(()) } - fn validate_rvalue(&self, rvalue: &Rvalue<'tcx>) -> Result<(), Unpromotable> { + fn validate_rvalue(&mut self, rvalue: &Rvalue<'tcx>) -> Result<(), Unpromotable> { match rvalue { Rvalue::Use(operand) | Rvalue::Repeat(operand, _) => { self.validate_operand(operand)?; @@ -623,7 +633,7 @@ impl<'tcx> Validator<'_, 'tcx> { } fn validate_call( - &self, + &mut self, callee: &Operand<'tcx>, args: &[Operand<'tcx>], ) -> Result<(), Unpromotable> { @@ -665,10 +675,10 @@ impl<'tcx> Validator<'_, 'tcx> { // FIXME(eddyb) remove the differences for promotability in `static`, `const`, `const fn`. pub fn validate_candidates( ccx: &ConstCx<'_, '_>, - temps: &IndexVec<Local, TempState>, + temps: &mut IndexVec<Local, TempState>, candidates: &[Candidate], ) -> Vec<Candidate> { - let validator = Validator { ccx, temps }; + let mut validator = Validator { ccx, temps }; candidates .iter() @@ -720,7 +730,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> { fn promote_temp(&mut self, temp: Local) -> Local { let old_keep_original = self.keep_original; let loc = match self.temps[temp] { - TempState::Defined { location, uses } if uses > 0 => { + TempState::Defined { location, uses, .. } if uses > 0 => { if uses > 1 { self.keep_original = true; } |