| //! Validates the MIR to ensure that invariants are upheld. |
| |
| use rustc_data_structures::fx::{FxHashMap, FxHashSet}; |
| use rustc_index::bit_set::BitSet; |
| use rustc_index::vec::IndexVec; |
| use rustc_infer::traits::Reveal; |
| use rustc_middle::mir::interpret::Scalar; |
| use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor}; |
| use rustc_middle::mir::{ |
| traversal, BasicBlock, BinOp, Body, BorrowKind, CastKind, CopyNonOverlapping, Local, Location, |
| MirPass, MirPhase, NonDivergingIntrinsic, Operand, Place, PlaceElem, PlaceRef, ProjectionElem, |
| RetagKind, RuntimePhase, Rvalue, SourceScope, Statement, StatementKind, Terminator, |
| TerminatorKind, UnOp, UnwindAction, VarDebugInfo, VarDebugInfoContents, START_BLOCK, |
| }; |
| use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitableExt}; |
| use rustc_mir_dataflow::impls::MaybeStorageLive; |
| use rustc_mir_dataflow::storage::always_storage_live_locals; |
| use rustc_mir_dataflow::{Analysis, ResultsCursor}; |
| use rustc_target::abi::{Size, FIRST_VARIANT}; |
| |
| #[derive(Copy, Clone, Debug, PartialEq, Eq)] |
| enum EdgeKind { |
| Unwind, |
| Normal, |
| } |
| |
| pub struct Validator { |
| /// Describes at which point in the pipeline this validation is happening. |
| pub when: String, |
| /// The phase for which we are upholding the dialect. If the given phase forbids a specific |
| /// element, this validator will now emit errors if that specific element is encountered. |
| /// Note that phases that change the dialect cause all *following* phases to check the |
| /// invariants of the new dialect. A phase that changes dialects never checks the new invariants |
| /// itself. |
| pub mir_phase: MirPhase, |
| } |
| |
| impl<'tcx> MirPass<'tcx> for Validator { |
| fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { |
| // FIXME(JakobDegen): These bodies never instantiated in codegend anyway, so it's not |
| // terribly important that they pass the validator. However, I think other passes might |
| // still see them, in which case they might be surprised. It would probably be better if we |
| // didn't put this through the MIR pipeline at all. |
| if matches!(body.source.instance, InstanceDef::Intrinsic(..) | InstanceDef::Virtual(..)) { |
| return; |
| } |
| let def_id = body.source.def_id(); |
| let mir_phase = self.mir_phase; |
| let param_env = match mir_phase.reveal() { |
| Reveal::UserFacing => tcx.param_env(def_id), |
| Reveal::All => tcx.param_env_reveal_all_normalized(def_id), |
| }; |
| |
| let always_live_locals = always_storage_live_locals(body); |
| let storage_liveness = MaybeStorageLive::new(std::borrow::Cow::Owned(always_live_locals)) |
| .into_engine(tcx, body) |
| .iterate_to_fixpoint() |
| .into_results_cursor(body); |
| |
| let mut checker = TypeChecker { |
| when: &self.when, |
| body, |
| tcx, |
| param_env, |
| mir_phase, |
| unwind_edge_count: 0, |
| reachable_blocks: traversal::reachable_as_bitset(body), |
| storage_liveness, |
| place_cache: Vec::new(), |
| value_cache: Vec::new(), |
| }; |
| checker.visit_body(body); |
| checker.check_cleanup_control_flow(); |
| |
| if let MirPhase::Runtime(_) = body.phase { |
| if let ty::InstanceDef::Item(_) = body.source.instance { |
| if body.has_free_regions() { |
| checker.fail( |
| Location::START, |
| format!("Free regions in optimized {} MIR", body.phase.name()), |
| ); |
| } |
| } |
| } |
| } |
| } |
| |
| struct TypeChecker<'a, 'tcx> { |
| when: &'a str, |
| body: &'a Body<'tcx>, |
| tcx: TyCtxt<'tcx>, |
| param_env: ParamEnv<'tcx>, |
| mir_phase: MirPhase, |
| unwind_edge_count: usize, |
| reachable_blocks: BitSet<BasicBlock>, |
| storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>, |
| place_cache: Vec<PlaceRef<'tcx>>, |
| value_cache: Vec<u128>, |
| } |
| |
| impl<'a, 'tcx> TypeChecker<'a, 'tcx> { |
| #[track_caller] |
| fn fail(&self, location: Location, msg: impl AsRef<str>) { |
| let span = self.body.source_info(location).span; |
| // We use `delay_span_bug` as we might see broken MIR when other errors have already |
| // occurred. |
| self.tcx.sess.diagnostic().delay_span_bug( |
| span, |
| &format!( |
| "broken MIR in {:?} ({}) at {:?}:\n{}", |
| self.body.source.instance, |
| self.when, |
| location, |
| msg.as_ref() |
| ), |
| ); |
| } |
| |
| fn check_edge(&mut self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) { |
| if bb == START_BLOCK { |
| self.fail(location, "start block must not have predecessors") |
| } |
| if let Some(bb) = self.body.basic_blocks.get(bb) { |
| let src = self.body.basic_blocks.get(location.block).unwrap(); |
| match (src.is_cleanup, bb.is_cleanup, edge_kind) { |
| // Non-cleanup blocks can jump to non-cleanup blocks along non-unwind edges |
| (false, false, EdgeKind::Normal) |
| // Cleanup blocks can jump to cleanup blocks along non-unwind edges |
| | (true, true, EdgeKind::Normal) => {} |
| // Non-cleanup blocks can jump to cleanup blocks along unwind edges |
| (false, true, EdgeKind::Unwind) => { |
| self.unwind_edge_count += 1; |
| } |
| // All other jumps are invalid |
| _ => { |
| self.fail( |
| location, |
| format!( |
| "{:?} edge to {:?} violates unwind invariants (cleanup {:?} -> {:?})", |
| edge_kind, |
| bb, |
| src.is_cleanup, |
| bb.is_cleanup, |
| ) |
| ) |
| } |
| } |
| } else { |
| self.fail(location, format!("encountered jump to invalid basic block {:?}", bb)) |
| } |
| } |
| |
| fn check_cleanup_control_flow(&self) { |
| if self.unwind_edge_count <= 1 { |
| return; |
| } |
| let doms = self.body.basic_blocks.dominators(); |
| let mut post_contract_node = FxHashMap::default(); |
| // Reusing the allocation across invocations of the closure |
| let mut dom_path = vec![]; |
| let mut get_post_contract_node = |mut bb| { |
| let root = loop { |
| if let Some(root) = post_contract_node.get(&bb) { |
| break *root; |
| } |
| let parent = doms.immediate_dominator(bb); |
| dom_path.push(bb); |
| if !self.body.basic_blocks[parent].is_cleanup { |
| break bb; |
| } |
| bb = parent; |
| }; |
| for bb in dom_path.drain(..) { |
| post_contract_node.insert(bb, root); |
| } |
| root |
| }; |
| |
| let mut parent = IndexVec::from_elem(None, &self.body.basic_blocks); |
| for (bb, bb_data) in self.body.basic_blocks.iter_enumerated() { |
| if !bb_data.is_cleanup || !self.reachable_blocks.contains(bb) { |
| continue; |
| } |
| let bb = get_post_contract_node(bb); |
| for s in bb_data.terminator().successors() { |
| let s = get_post_contract_node(s); |
| if s == bb { |
| continue; |
| } |
| let parent = &mut parent[bb]; |
| match parent { |
| None => { |
| *parent = Some(s); |
| } |
| Some(e) if *e == s => (), |
| Some(e) => self.fail( |
| Location { block: bb, statement_index: 0 }, |
| format!( |
| "Cleanup control flow violation: The blocks dominated by {:?} have edges to both {:?} and {:?}", |
| bb, |
| s, |
| *e |
| ) |
| ), |
| } |
| } |
| } |
| |
| // Check for cycles |
| let mut stack = FxHashSet::default(); |
| for i in 0..parent.len() { |
| let mut bb = BasicBlock::from_usize(i); |
| stack.clear(); |
| stack.insert(bb); |
| loop { |
| let Some(parent)= parent[bb].take() else { |
| break |
| }; |
| let no_cycle = stack.insert(parent); |
| if !no_cycle { |
| self.fail( |
| Location { block: bb, statement_index: 0 }, |
| format!( |
| "Cleanup control flow violation: Cycle involving edge {:?} -> {:?}", |
| bb, parent, |
| ), |
| ); |
| break; |
| } |
| bb = parent; |
| } |
| } |
| } |
| |
| fn check_unwind_edge(&mut self, location: Location, unwind: UnwindAction) { |
| let is_cleanup = self.body.basic_blocks[location.block].is_cleanup; |
| match unwind { |
| UnwindAction::Cleanup(unwind) => { |
| if is_cleanup { |
| self.fail(location, "unwind on cleanup block"); |
| } |
| self.check_edge(location, unwind, EdgeKind::Unwind); |
| } |
| UnwindAction::Continue => { |
| if is_cleanup { |
| self.fail(location, "unwind on cleanup block"); |
| } |
| } |
| UnwindAction::Unreachable | UnwindAction::Terminate => (), |
| } |
| } |
| |
| /// Check if src can be assigned into dest. |
| /// This is not precise, it will accept some incorrect assignments. |
| fn mir_assign_valid_types(&self, src: Ty<'tcx>, dest: Ty<'tcx>) -> bool { |
| // Fast path before we normalize. |
| if src == dest { |
| // Equal types, all is good. |
| return true; |
| } |
| |
| // We sometimes have to use `defining_opaque_types` for subtyping |
| // to succeed here and figuring out how exactly that should work |
| // is annoying. It is harmless enough to just not validate anything |
| // in that case. We still check this after analysis as all opque |
| // types have been revealed at this point. |
| if (src, dest).has_opaque_types() { |
| return true; |
| } |
| |
| crate::util::is_subtype(self.tcx, self.param_env, src, dest) |
| } |
| } |
| |
| impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> { |
| fn visit_local(&mut self, local: Local, context: PlaceContext, location: Location) { |
| if self.body.local_decls.get(local).is_none() { |
| self.fail( |
| location, |
| format!("local {:?} has no corresponding declaration in `body.local_decls`", local), |
| ); |
| } |
| |
| if self.reachable_blocks.contains(location.block) && context.is_use() { |
| // We check that the local is live whenever it is used. Technically, violating this |
| // restriction is only UB and not actually indicative of not well-formed MIR. This means |
| // that an optimization which turns MIR that already has UB into MIR that fails this |
| // check is not necessarily wrong. However, we have no such optimizations at the moment, |
| // and so we include this check anyway to help us catch bugs. If you happen to write an |
| // optimization that might cause this to incorrectly fire, feel free to remove this |
| // check. |
| 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) { |
| // This check is somewhat expensive, so only run it when -Zvalidate-mir is passed. |
| if self.tcx.sess.opts.unstable_opts.validate_mir |
| && self.mir_phase < MirPhase::Runtime(RuntimePhase::Initial) |
| { |
| // `Operand::Copy` is only supposed to be used with `Copy` types. |
| if let Operand::Copy(place) = operand { |
| let ty = place.ty(&self.body.local_decls, self.tcx).ty; |
| |
| if !ty.is_copy_modulo_regions(self.tcx, self.param_env) { |
| self.fail(location, format!("`Operand::Copy` with non-`Copy` type {}", ty)); |
| } |
| } |
| } |
| |
| self.super_operand(operand, location); |
| } |
| |
| fn visit_projection_elem( |
| &mut self, |
| local: Local, |
| proj_base: &[PlaceElem<'tcx>], |
| elem: PlaceElem<'tcx>, |
| context: PlaceContext, |
| location: Location, |
| ) { |
| match elem { |
| ProjectionElem::Index(index) => { |
| let index_ty = self.body.local_decls[index].ty; |
| if index_ty != self.tcx.types.usize { |
| self.fail(location, format!("bad index ({:?} != usize)", index_ty)) |
| } |
| } |
| ProjectionElem::Deref |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::PostCleanup) => |
| { |
| let base_ty = Place::ty_from(local, proj_base, &self.body.local_decls, self.tcx).ty; |
| |
| if base_ty.is_box() { |
| self.fail( |
| location, |
| format!("{:?} dereferenced after ElaborateBoxDerefs", base_ty), |
| ) |
| } |
| } |
| ProjectionElem::Field(f, ty) => { |
| let parent = Place { local, projection: self.tcx.mk_place_elems(proj_base) }; |
| let parent_ty = parent.ty(&self.body.local_decls, self.tcx); |
| let fail_out_of_bounds = |this: &Self, location| { |
| this.fail(location, format!("Out of bounds field {:?} for {:?}", f, parent_ty)); |
| }; |
| let check_equal = |this: &Self, location, f_ty| { |
| if !this.mir_assign_valid_types(ty, f_ty) { |
| this.fail( |
| location, |
| format!( |
| "Field projection `{:?}.{:?}` specified type `{:?}`, but actual type is `{:?}`", |
| parent, f, ty, f_ty |
| ) |
| ) |
| } |
| }; |
| |
| let kind = match parent_ty.ty.kind() { |
| &ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => { |
| self.tcx.type_of(def_id).subst(self.tcx, substs).kind() |
| } |
| kind => kind, |
| }; |
| |
| match kind { |
| ty::Tuple(fields) => { |
| let Some(f_ty) = fields.get(f.as_usize()) else { |
| fail_out_of_bounds(self, location); |
| return; |
| }; |
| check_equal(self, location, *f_ty); |
| } |
| ty::Adt(adt_def, substs) => { |
| let var = parent_ty.variant_index.unwrap_or(FIRST_VARIANT); |
| let Some(field) = adt_def.variant(var).fields.get(f) else { |
| fail_out_of_bounds(self, location); |
| return; |
| }; |
| check_equal(self, location, field.ty(self.tcx, substs)); |
| } |
| ty::Closure(_, substs) => { |
| let substs = substs.as_closure(); |
| let Some(f_ty) = substs.upvar_tys().nth(f.as_usize()) else { |
| fail_out_of_bounds(self, location); |
| return; |
| }; |
| check_equal(self, location, f_ty); |
| } |
| &ty::Generator(def_id, substs, _) => { |
| let f_ty = if let Some(var) = parent_ty.variant_index { |
| let gen_body = if def_id == self.body.source.def_id() { |
| self.body |
| } else { |
| self.tcx.optimized_mir(def_id) |
| }; |
| |
| let Some(layout) = gen_body.generator_layout() else { |
| self.fail(location, format!("No generator layout for {:?}", parent_ty)); |
| return; |
| }; |
| |
| let Some(&local) = layout.variant_fields[var].get(f) else { |
| fail_out_of_bounds(self, location); |
| return; |
| }; |
| |
| let Some(f_ty) = layout.field_tys.get(local) else { |
| self.fail(location, format!("Out of bounds local {:?} for {:?}", local, parent_ty)); |
| return; |
| }; |
| |
| f_ty.ty |
| } else { |
| let Some(f_ty) = substs.as_generator().prefix_tys().nth(f.index()) else { |
| fail_out_of_bounds(self, location); |
| return; |
| }; |
| |
| f_ty |
| }; |
| |
| check_equal(self, location, f_ty); |
| } |
| _ => { |
| self.fail(location, format!("{:?} does not have fields", parent_ty.ty)); |
| } |
| } |
| } |
| _ => {} |
| } |
| self.super_projection_elem(local, proj_base, elem, context, location); |
| } |
| |
| fn visit_var_debug_info(&mut self, debuginfo: &VarDebugInfo<'tcx>) { |
| let check_place = |place: Place<'_>| { |
| if place.projection.iter().any(|p| !p.can_use_in_debuginfo()) { |
| self.fail( |
| START_BLOCK.start_location(), |
| format!("illegal place {:?} in debuginfo for {:?}", place, debuginfo.name), |
| ); |
| } |
| }; |
| match debuginfo.value { |
| VarDebugInfoContents::Const(_) => {} |
| VarDebugInfoContents::Place(place) => check_place(place), |
| VarDebugInfoContents::Composite { ty, ref fragments } => { |
| for f in fragments { |
| check_place(f.contents); |
| if ty.is_union() || ty.is_enum() { |
| self.fail( |
| START_BLOCK.start_location(), |
| format!("invalid type {:?} for composite debuginfo", ty), |
| ); |
| } |
| if f.projection.iter().any(|p| !matches!(p, PlaceElem::Field(..))) { |
| self.fail( |
| START_BLOCK.start_location(), |
| format!( |
| "illegal projection {:?} in debuginfo for {:?}", |
| f.projection, debuginfo.name |
| ), |
| ); |
| } |
| } |
| } |
| } |
| self.super_var_debug_info(debuginfo); |
| } |
| |
| fn visit_place(&mut self, place: &Place<'tcx>, cntxt: PlaceContext, location: Location) { |
| // Set off any `bug!`s in the type computation code |
| let _ = place.ty(&self.body.local_decls, self.tcx); |
| |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) |
| && place.projection.len() > 1 |
| && cntxt != PlaceContext::NonUse(NonUseContext::VarDebugInfo) |
| && place.projection[1..].contains(&ProjectionElem::Deref) |
| { |
| self.fail(location, format!("{:?}, has deref at the wrong place", place)); |
| } |
| |
| self.super_place(place, cntxt, location); |
| } |
| |
| fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) { |
| macro_rules! check_kinds { |
| ($t:expr, $text:literal, $($patterns:tt)*) => { |
| if !matches!(($t).kind(), $($patterns)*) { |
| self.fail(location, format!($text, $t)); |
| } |
| }; |
| } |
| match rvalue { |
| Rvalue::Use(_) | Rvalue::CopyForDeref(_) | Rvalue::Aggregate(..) => {} |
| Rvalue::Ref(_, BorrowKind::Shallow, _) => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`Assign` statement with a `Shallow` borrow should have been removed in runtime MIR", |
| ); |
| } |
| } |
| Rvalue::Ref(..) => {} |
| Rvalue::Len(p) => { |
| let pty = p.ty(&self.body.local_decls, self.tcx).ty; |
| check_kinds!( |
| pty, |
| "Cannot compute length of non-array type {:?}", |
| ty::Array(..) | ty::Slice(..) |
| ); |
| } |
| Rvalue::BinaryOp(op, vals) => { |
| use BinOp::*; |
| let a = vals.0.ty(&self.body.local_decls, self.tcx); |
| let b = vals.1.ty(&self.body.local_decls, self.tcx); |
| match op { |
| Offset => { |
| check_kinds!(a, "Cannot offset non-pointer type {:?}", ty::RawPtr(..)); |
| if b != self.tcx.types.isize && b != self.tcx.types.usize { |
| self.fail(location, format!("Cannot offset by non-isize type {:?}", b)); |
| } |
| } |
| Eq | Lt | Le | Ne | Ge | Gt => { |
| for x in [a, b] { |
| check_kinds!( |
| x, |
| "Cannot compare type {:?}", |
| ty::Bool |
| | ty::Char |
| | ty::Int(..) |
| | ty::Uint(..) |
| | ty::Float(..) |
| | ty::RawPtr(..) |
| | ty::FnPtr(..) |
| ) |
| } |
| // The function pointer types can have lifetimes |
| if !self.mir_assign_valid_types(a, b) { |
| self.fail( |
| location, |
| format!("Cannot compare unequal types {:?} and {:?}", a, b), |
| ); |
| } |
| } |
| Shl | Shr => { |
| for x in [a, b] { |
| check_kinds!( |
| x, |
| "Cannot shift non-integer type {:?}", |
| ty::Uint(..) | ty::Int(..) |
| ) |
| } |
| } |
| BitAnd | BitOr | BitXor => { |
| for x in [a, b] { |
| check_kinds!( |
| x, |
| "Cannot perform bitwise op on type {:?}", |
| ty::Uint(..) | ty::Int(..) | ty::Bool |
| ) |
| } |
| if a != b { |
| self.fail( |
| location, |
| format!( |
| "Cannot perform bitwise op on unequal types {:?} and {:?}", |
| a, b |
| ), |
| ); |
| } |
| } |
| Add | Sub | Mul | Div | Rem => { |
| for x in [a, b] { |
| check_kinds!( |
| x, |
| "Cannot perform arithmetic on type {:?}", |
| ty::Uint(..) | ty::Int(..) | ty::Float(..) |
| ) |
| } |
| if a != b { |
| self.fail( |
| location, |
| format!( |
| "Cannot perform arithmetic on unequal types {:?} and {:?}", |
| a, b |
| ), |
| ); |
| } |
| } |
| } |
| } |
| Rvalue::CheckedBinaryOp(op, vals) => { |
| use BinOp::*; |
| let a = vals.0.ty(&self.body.local_decls, self.tcx); |
| let b = vals.1.ty(&self.body.local_decls, self.tcx); |
| match op { |
| Add | Sub | Mul => { |
| for x in [a, b] { |
| check_kinds!( |
| x, |
| "Cannot perform checked arithmetic on type {:?}", |
| ty::Uint(..) | ty::Int(..) |
| ) |
| } |
| if a != b { |
| self.fail( |
| location, |
| format!( |
| "Cannot perform checked arithmetic on unequal types {:?} and {:?}", |
| a, b |
| ), |
| ); |
| } |
| } |
| _ => self.fail(location, format!("There is no checked version of {:?}", op)), |
| } |
| } |
| Rvalue::UnaryOp(op, operand) => { |
| let a = operand.ty(&self.body.local_decls, self.tcx); |
| match op { |
| UnOp::Neg => { |
| check_kinds!(a, "Cannot negate type {:?}", ty::Int(..) | ty::Float(..)) |
| } |
| UnOp::Not => { |
| check_kinds!( |
| a, |
| "Cannot binary not type {:?}", |
| ty::Int(..) | ty::Uint(..) | ty::Bool |
| ); |
| } |
| } |
| } |
| Rvalue::ShallowInitBox(operand, _) => { |
| let a = operand.ty(&self.body.local_decls, self.tcx); |
| check_kinds!(a, "Cannot shallow init type {:?}", ty::RawPtr(..)); |
| } |
| Rvalue::Cast(kind, operand, target_type) => { |
| let op_ty = operand.ty(self.body, self.tcx); |
| match kind { |
| CastKind::DynStar => { |
| // FIXME(dyn-star): make sure nothing needs to be done here. |
| } |
| // FIXME: Add Checks for these |
| CastKind::PointerFromExposedAddress |
| | CastKind::PointerExposeAddress |
| | CastKind::Pointer(_) => {} |
| CastKind::IntToInt | CastKind::IntToFloat => { |
| let input_valid = op_ty.is_integral() || op_ty.is_char() || op_ty.is_bool(); |
| let target_valid = target_type.is_numeric() || target_type.is_char(); |
| if !input_valid || !target_valid { |
| self.fail( |
| location, |
| format!("Wrong cast kind {kind:?} for the type {op_ty}",), |
| ); |
| } |
| } |
| CastKind::FnPtrToPtr | CastKind::PtrToPtr => { |
| if !(op_ty.is_any_ptr() && target_type.is_unsafe_ptr()) { |
| self.fail(location, "Can't cast {op_ty} into 'Ptr'"); |
| } |
| } |
| CastKind::FloatToFloat | CastKind::FloatToInt => { |
| if !op_ty.is_floating_point() || !target_type.is_numeric() { |
| self.fail( |
| location, |
| format!( |
| "Trying to cast non 'Float' as {kind:?} into {target_type:?}" |
| ), |
| ); |
| } |
| } |
| CastKind::Transmute => { |
| if let MirPhase::Runtime(..) = self.mir_phase { |
| // Unlike `mem::transmute`, a MIR `Transmute` is well-formed |
| // for any two `Sized` types, just potentially UB to run. |
| |
| if !op_ty.is_sized(self.tcx, self.param_env) { |
| self.fail( |
| location, |
| format!("Cannot transmute from non-`Sized` type {op_ty:?}"), |
| ); |
| } |
| if !target_type.is_sized(self.tcx, self.param_env) { |
| self.fail( |
| location, |
| format!("Cannot transmute to non-`Sized` type {target_type:?}"), |
| ); |
| } |
| } else { |
| self.fail( |
| location, |
| format!( |
| "Transmute is not supported in non-runtime phase {:?}.", |
| self.mir_phase |
| ), |
| ); |
| } |
| } |
| } |
| } |
| Rvalue::Repeat(_, _) |
| | Rvalue::ThreadLocalRef(_) |
| | Rvalue::AddressOf(_, _) |
| | Rvalue::NullaryOp(_, _) |
| | Rvalue::Discriminant(_) => {} |
| } |
| self.super_rvalue(rvalue, location); |
| } |
| |
| fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) { |
| match &statement.kind { |
| StatementKind::Assign(box (dest, rvalue)) => { |
| // LHS and RHS of the assignment must have the same type. |
| let left_ty = dest.ty(&self.body.local_decls, self.tcx).ty; |
| let right_ty = rvalue.ty(&self.body.local_decls, self.tcx); |
| if !self.mir_assign_valid_types(right_ty, left_ty) { |
| self.fail( |
| location, |
| format!( |
| "encountered `{:?}` with incompatible types:\n\ |
| left-hand side has type: {}\n\ |
| right-hand side has type: {}", |
| statement.kind, left_ty, right_ty, |
| ), |
| ); |
| } |
| if let Rvalue::CopyForDeref(place) = rvalue { |
| if place.ty(&self.body.local_decls, self.tcx).ty.builtin_deref(true).is_none() { |
| self.fail( |
| location, |
| "`CopyForDeref` should only be used for dereferenceable types", |
| ) |
| } |
| } |
| // FIXME(JakobDegen): Check this for all rvalues, not just this one. |
| if let Rvalue::Use(Operand::Copy(src) | Operand::Move(src)) = rvalue { |
| // The sides of an assignment must not alias. Currently this just checks whether |
| // the places are identical. |
| if dest == src { |
| self.fail( |
| location, |
| "encountered `Assign` statement with overlapping memory", |
| ); |
| } |
| } |
| } |
| StatementKind::PlaceMention(..) => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`PlaceMention` should have been removed after drop lowering phase", |
| ); |
| } |
| } |
| StatementKind::AscribeUserType(..) => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`AscribeUserType` should have been removed after drop lowering phase", |
| ); |
| } |
| } |
| StatementKind::FakeRead(..) => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`FakeRead` should have been removed after drop lowering phase", |
| ); |
| } |
| } |
| StatementKind::Intrinsic(box NonDivergingIntrinsic::Assume(op)) => { |
| let ty = op.ty(&self.body.local_decls, self.tcx); |
| if !ty.is_bool() { |
| self.fail( |
| location, |
| format!("`assume` argument must be `bool`, but got: `{}`", ty), |
| ); |
| } |
| } |
| StatementKind::Intrinsic(box NonDivergingIntrinsic::CopyNonOverlapping( |
| CopyNonOverlapping { src, dst, count }, |
| )) => { |
| let src_ty = src.ty(&self.body.local_decls, self.tcx); |
| let op_src_ty = if let Some(src_deref) = src_ty.builtin_deref(true) { |
| src_deref.ty |
| } else { |
| self.fail( |
| location, |
| format!("Expected src to be ptr in copy_nonoverlapping, got: {}", src_ty), |
| ); |
| return; |
| }; |
| let dst_ty = dst.ty(&self.body.local_decls, self.tcx); |
| let op_dst_ty = if let Some(dst_deref) = dst_ty.builtin_deref(true) { |
| dst_deref.ty |
| } else { |
| self.fail( |
| location, |
| format!("Expected dst to be ptr in copy_nonoverlapping, got: {}", dst_ty), |
| ); |
| return; |
| }; |
| // since CopyNonOverlapping is parametrized by 1 type, |
| // we only need to check that they are equal and not keep an extra parameter. |
| if !self.mir_assign_valid_types(op_src_ty, op_dst_ty) { |
| self.fail(location, format!("bad arg ({:?} != {:?})", op_src_ty, op_dst_ty)); |
| } |
| |
| let op_cnt_ty = count.ty(&self.body.local_decls, self.tcx); |
| if op_cnt_ty != self.tcx.types.usize { |
| self.fail(location, format!("bad arg ({:?} != usize)", op_cnt_ty)) |
| } |
| } |
| StatementKind::SetDiscriminant { place, .. } => { |
| if self.mir_phase < MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail(location, "`SetDiscriminant`is not allowed until deaggregation"); |
| } |
| let pty = place.ty(&self.body.local_decls, self.tcx).ty.kind(); |
| if !matches!(pty, ty::Adt(..) | ty::Generator(..) | ty::Alias(ty::Opaque, ..)) { |
| self.fail( |
| location, |
| format!( |
| "`SetDiscriminant` is only allowed on ADTs and generators, not {:?}", |
| pty |
| ), |
| ); |
| } |
| } |
| StatementKind::Deinit(..) => { |
| if self.mir_phase < MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail(location, "`Deinit`is not allowed until deaggregation"); |
| } |
| } |
| StatementKind::Retag(kind, _) => { |
| // FIXME(JakobDegen) The validator should check that `self.mir_phase < |
| // DropsLowered`. However, this causes ICEs with generation of drop shims, which |
| // seem to fail to set their `MirPhase` correctly. |
| if matches!(kind, RetagKind::Raw | RetagKind::TwoPhase) { |
| self.fail(location, format!("explicit `{:?}` is forbidden", kind)); |
| } |
| } |
| StatementKind::StorageLive(local) => { |
| // We check that the local is not live when entering a `StorageLive` for it. |
| // Technically, violating this restriction is only UB and not actually indicative |
| // of not well-formed MIR. This means that an optimization which turns MIR that |
| // already has UB into MIR that fails this check is not necessarily wrong. However, |
| // we have no such optimizations at the moment, and so we include this check anyway |
| // to help us catch bugs. If you happen to write an optimization that might cause |
| // this to incorrectly fire, feel free to remove this check. |
| if self.reachable_blocks.contains(location.block) { |
| self.storage_liveness.seek_before_primary_effect(location); |
| let locals_with_storage = self.storage_liveness.get(); |
| if locals_with_storage.contains(*local) { |
| self.fail( |
| location, |
| format!("StorageLive({local:?}) which already has storage here"), |
| ); |
| } |
| } |
| } |
| StatementKind::StorageDead(_) |
| | StatementKind::Coverage(_) |
| | StatementKind::ConstEvalCounter |
| | StatementKind::Nop => {} |
| } |
| |
| self.super_statement(statement, location); |
| } |
| |
| fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) { |
| match &terminator.kind { |
| TerminatorKind::Goto { target } => { |
| self.check_edge(location, *target, EdgeKind::Normal); |
| } |
| TerminatorKind::SwitchInt { targets, discr } => { |
| let switch_ty = discr.ty(&self.body.local_decls, self.tcx); |
| |
| let target_width = self.tcx.sess.target.pointer_width; |
| |
| let size = Size::from_bits(match switch_ty.kind() { |
| ty::Uint(uint) => uint.normalize(target_width).bit_width().unwrap(), |
| ty::Int(int) => int.normalize(target_width).bit_width().unwrap(), |
| ty::Char => 32, |
| ty::Bool => 1, |
| other => bug!("unhandled type: {:?}", other), |
| }); |
| |
| for (value, target) in targets.iter() { |
| if Scalar::<()>::try_from_uint(value, size).is_none() { |
| self.fail( |
| location, |
| format!("the value {:#x} is not a proper {:?}", value, switch_ty), |
| ) |
| } |
| |
| self.check_edge(location, target, EdgeKind::Normal); |
| } |
| self.check_edge(location, targets.otherwise(), EdgeKind::Normal); |
| |
| self.value_cache.clear(); |
| self.value_cache.extend(targets.iter().map(|(value, _)| value)); |
| let all_len = self.value_cache.len(); |
| self.value_cache.sort_unstable(); |
| self.value_cache.dedup(); |
| let has_duplicates = all_len != self.value_cache.len(); |
| if has_duplicates { |
| self.fail( |
| location, |
| format!( |
| "duplicated values in `SwitchInt` terminator: {:?}", |
| terminator.kind, |
| ), |
| ); |
| } |
| } |
| TerminatorKind::Drop { target, unwind, .. } => { |
| self.check_edge(location, *target, EdgeKind::Normal); |
| self.check_unwind_edge(location, *unwind); |
| } |
| TerminatorKind::Call { func, args, destination, target, unwind, .. } => { |
| let func_ty = func.ty(&self.body.local_decls, self.tcx); |
| match func_ty.kind() { |
| ty::FnPtr(..) | ty::FnDef(..) => {} |
| _ => self.fail( |
| location, |
| format!("encountered non-callable type {} in `Call` terminator", func_ty), |
| ), |
| } |
| if let Some(target) = target { |
| self.check_edge(location, *target, EdgeKind::Normal); |
| } |
| self.check_unwind_edge(location, *unwind); |
| |
| // The call destination place and Operand::Move place used as an argument might be |
| // passed by a reference to the callee. Consequently they must be non-overlapping. |
| // Currently this simply checks for duplicate places. |
| self.place_cache.clear(); |
| self.place_cache.push(destination.as_ref()); |
| for arg in args { |
| if let Operand::Move(place) = arg { |
| self.place_cache.push(place.as_ref()); |
| } |
| } |
| let all_len = self.place_cache.len(); |
| let mut dedup = FxHashSet::default(); |
| self.place_cache.retain(|p| dedup.insert(*p)); |
| let has_duplicates = all_len != self.place_cache.len(); |
| if has_duplicates { |
| self.fail( |
| location, |
| format!( |
| "encountered overlapping memory in `Call` terminator: {:?}", |
| terminator.kind, |
| ), |
| ); |
| } |
| } |
| TerminatorKind::Assert { cond, target, unwind, .. } => { |
| let cond_ty = cond.ty(&self.body.local_decls, self.tcx); |
| if cond_ty != self.tcx.types.bool { |
| self.fail( |
| location, |
| format!( |
| "encountered non-boolean condition of type {} in `Assert` terminator", |
| cond_ty |
| ), |
| ); |
| } |
| self.check_edge(location, *target, EdgeKind::Normal); |
| self.check_unwind_edge(location, *unwind); |
| } |
| TerminatorKind::Yield { resume, drop, .. } => { |
| if self.body.generator.is_none() { |
| self.fail(location, "`Yield` cannot appear outside generator bodies"); |
| } |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail(location, "`Yield` should have been replaced by generator lowering"); |
| } |
| self.check_edge(location, *resume, EdgeKind::Normal); |
| if let Some(drop) = drop { |
| self.check_edge(location, *drop, EdgeKind::Normal); |
| } |
| } |
| TerminatorKind::FalseEdge { real_target, imaginary_target } => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`FalseEdge` should have been removed after drop elaboration", |
| ); |
| } |
| self.check_edge(location, *real_target, EdgeKind::Normal); |
| self.check_edge(location, *imaginary_target, EdgeKind::Normal); |
| } |
| TerminatorKind::FalseUnwind { real_target, unwind } => { |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`FalseUnwind` should have been removed after drop elaboration", |
| ); |
| } |
| self.check_edge(location, *real_target, EdgeKind::Normal); |
| self.check_unwind_edge(location, *unwind); |
| } |
| TerminatorKind::InlineAsm { destination, unwind, .. } => { |
| if let Some(destination) = destination { |
| self.check_edge(location, *destination, EdgeKind::Normal); |
| } |
| self.check_unwind_edge(location, *unwind); |
| } |
| TerminatorKind::GeneratorDrop => { |
| if self.body.generator.is_none() { |
| self.fail(location, "`GeneratorDrop` cannot appear outside generator bodies"); |
| } |
| if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) { |
| self.fail( |
| location, |
| "`GeneratorDrop` should have been replaced by generator lowering", |
| ); |
| } |
| } |
| TerminatorKind::Resume | TerminatorKind::Terminate => { |
| let bb = location.block; |
| if !self.body.basic_blocks[bb].is_cleanup { |
| self.fail( |
| location, |
| "Cannot `Resume` or `Terminate` from non-cleanup basic block", |
| ) |
| } |
| } |
| TerminatorKind::Return => { |
| let bb = location.block; |
| if self.body.basic_blocks[bb].is_cleanup { |
| self.fail(location, "Cannot `Return` from cleanup basic block") |
| } |
| } |
| TerminatorKind::Unreachable => {} |
| } |
| |
| self.super_terminator(terminator, location); |
| } |
| |
| fn visit_source_scope(&mut self, scope: SourceScope) { |
| if self.body.source_scopes.get(scope).is_none() { |
| self.tcx.sess.diagnostic().delay_span_bug( |
| self.body.span, |
| &format!( |
| "broken MIR in {:?} ({}):\ninvalid source scope {:?}", |
| self.body.source.instance, self.when, scope, |
| ), |
| ); |
| } |
| } |
| } |
