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//! 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::IndexVec;
use rustc_infer::traits::Reveal;
use rustc_middle::mir::interpret::Scalar;
use rustc_middle::mir::visit::{NonUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*;
use rustc_middle::ty::{self, InstanceDef, ParamEnv, Ty, TyCtxt, TypeVisitableExt, Variance};
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};
use rustc_target::spec::abi::Abi;
use crate::util::is_within_packed;
use crate::util::relate_types;
#[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 can_unwind = if mir_phase <= MirPhase::Runtime(RuntimePhase::Initial) {
// In this case `AbortUnwindingCalls` haven't yet been executed.
true
} else if !tcx.def_kind(def_id).is_fn_like() {
true
} else {
let body_ty = tcx.type_of(def_id).skip_binder();
let body_abi = match body_ty.kind() {
ty::FnDef(..) => body_ty.fn_sig(tcx).abi(),
ty::Closure(..) => Abi::RustCall,
ty::Generator(..) => Abi::Rust,
_ => {
span_bug!(body.span, "unexpected body ty: {:?} phase {:?}", body_ty, mir_phase)
}
};
ty::layout::fn_can_unwind(tcx, Some(def_id), body_abi)
};
let mut cfg_checker = CfgChecker {
when: &self.when,
body,
tcx,
mir_phase,
unwind_edge_count: 0,
reachable_blocks: traversal::reachable_as_bitset(body),
storage_liveness,
place_cache: FxHashSet::default(),
value_cache: FxHashSet::default(),
can_unwind,
};
cfg_checker.visit_body(body);
cfg_checker.check_cleanup_control_flow();
// Also run the TypeChecker.
for (location, msg) in validate_types(tcx, self.mir_phase, param_env, body) {
cfg_checker.fail(location, msg);
}
if let MirPhase::Runtime(_) = body.phase {
if let ty::InstanceDef::Item(_) = body.source.instance {
if body.has_free_regions() {
cfg_checker.fail(
Location::START,
format!("Free regions in optimized {} MIR", body.phase.name()),
);
}
}
}
}
}
struct CfgChecker<'a, 'tcx> {
when: &'a str,
body: &'a Body<'tcx>,
tcx: TyCtxt<'tcx>,
mir_phase: MirPhase,
unwind_edge_count: usize,
reachable_blocks: BitSet<BasicBlock>,
storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>,
place_cache: FxHashSet<PlaceRef<'tcx>>,
value_cache: FxHashSet<u128>,
// If `false`, then the MIR must not contain `UnwindAction::Continue` or
// `TerminatorKind::Resume`.
can_unwind: bool,
}
impl<'a, 'tcx> CfgChecker<'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).unwrap();
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, "`UnwindAction::Cleanup` in cleanup block");
}
self.check_edge(location, unwind, EdgeKind::Unwind);
}
UnwindAction::Continue => {
if is_cleanup {
self.fail(location, "`UnwindAction::Continue` in cleanup block");
}
if !self.can_unwind {
self.fail(location, "`UnwindAction::Continue` in no-unwind function");
}
}
UnwindAction::Terminate(UnwindTerminateReason::InCleanup) => {
if !is_cleanup {
self.fail(
location,
"`UnwindAction::Terminate(InCleanup)` in a non-cleanup block",
);
}
}
// These are allowed everywhere.
UnwindAction::Unreachable | UnwindAction::Terminate(UnwindTerminateReason::Abi) => (),
}
}
}
impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'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 {local:?} has no corresponding declaration in `body.local_decls`"),
);
}
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 {local:?}, which has no storage here"));
}
}
}
fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
match &statement.kind {
StatementKind::Assign(box (dest, rvalue)) => {
// 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::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::SetDiscriminant { .. } => {
if self.mir_phase < MirPhase::Runtime(RuntimePhase::Initial) {
self.fail(location, "`SetDiscriminant`is not allowed until deaggregation");
}
}
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 `{kind:?}` is forbidden"));
}
}
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::Intrinsic(_)
| StatementKind::Coverage(_)
| StatementKind::ConstEvalCounter
| StatementKind::PlaceMention(..)
| 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: _ } => {
for (_, target) in targets.iter() {
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 has_duplicates = targets.iter().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 { args, destination, target, unwind, .. } => {
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
// and cannot be packed. Currently this simply checks for duplicate places.
self.place_cache.clear();
self.place_cache.insert(destination.as_ref());
if is_within_packed(self.tcx, &self.body.local_decls, *destination).is_some() {
// This is bad! The callee will expect the memory to be aligned.
self.fail(
location,
format!(
"encountered packed place in `Call` terminator destination: {:?}",
terminator.kind,
),
);
}
let mut has_duplicates = false;
for arg in args {
if let Operand::Move(place) = arg {
has_duplicates |= !self.place_cache.insert(place.as_ref());
if is_within_packed(self.tcx, &self.body.local_decls, *place).is_some() {
// This is bad! The callee will expect the memory to be aligned.
self.fail(
location,
format!(
"encountered `Move` of a packed place in `Call` terminator: {:?}",
terminator.kind,
),
);
}
}
}
if has_duplicates {
self.fail(
location,
format!(
"encountered overlapping memory in `Move` arguments to `Call` terminator: {:?}",
terminator.kind,
),
);
}
}
TerminatorKind::Assert { target, unwind, .. } => {
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::UnwindResume => {
let bb = location.block;
if !self.body.basic_blocks[bb].is_cleanup {
self.fail(location, "Cannot `UnwindResume` from non-cleanup basic block")
}
if !self.can_unwind {
self.fail(location, "Cannot `UnwindResume` in a function that cannot unwind")
}
}
TerminatorKind::UnwindTerminate(_) => {
let bb = location.block;
if !self.body.basic_blocks[bb].is_cleanup {
self.fail(location, "Cannot `UnwindTerminate` 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,
),
);
}
}
}
/// A faster version of the validation pass that only checks those things which may break when
/// instantiating any generic parameters.
pub fn validate_types<'tcx>(
tcx: TyCtxt<'tcx>,
mir_phase: MirPhase,
param_env: ty::ParamEnv<'tcx>,
body: &Body<'tcx>,
) -> Vec<(Location, String)> {
let mut type_checker = TypeChecker { body, tcx, param_env, mir_phase, failures: Vec::new() };
type_checker.visit_body(body);
type_checker.failures
}
struct TypeChecker<'a, 'tcx> {
body: &'a Body<'tcx>,
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
mir_phase: MirPhase,
failures: Vec<(Location, String)>,
}
impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
fn fail(&mut self, location: Location, msg: impl Into<String>) {
self.failures.push((location, msg.into()));
}
/// 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 opaque
// types have been revealed at this point.
if (src, dest).has_opaque_types() {
return true;
}
// After borrowck subtyping should be fully explicit via
// `Subtype` projections.
let variance = if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) {
Variance::Invariant
} else {
Variance::Covariant
};
crate::util::relate_types(self.tcx, self.param_env, variance, src, dest)
}
}
impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
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,
place_ref: PlaceRef<'tcx>,
elem: PlaceElem<'tcx>,
context: PlaceContext,
location: Location,
) {
match elem {
ProjectionElem::OpaqueCast(ty)
if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Initial) =>
{
self.fail(
location,
format!("explicit opaque type cast to `{ty}` after `RevealAll`"),
)
}
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 ({index_ty:?} != usize)"))
}
}
ProjectionElem::Deref
if self.mir_phase >= MirPhase::Runtime(RuntimePhase::PostCleanup) =>
{
let base_ty = place_ref.ty(&self.body.local_decls, self.tcx).ty;
if base_ty.is_box() {
self.fail(
location,
format!("{base_ty:?} dereferenced after ElaborateBoxDerefs"),
)
}
}
ProjectionElem::Field(f, ty) => {
let parent_ty = place_ref.ty(&self.body.local_decls, self.tcx);
let fail_out_of_bounds = |this: &mut Self, location| {
this.fail(location, format!("Out of bounds field {f:?} for {parent_ty:?}"));
};
let check_equal = |this: &mut Self, location, f_ty| {
if !this.mir_assign_valid_types(ty, f_ty) {
this.fail(
location,
format!(
"Field projection `{place_ref:?}.{f:?}` specified type `{ty:?}`, but actual type is `{f_ty:?}`"
)
)
}
};
let kind = match parent_ty.ty.kind() {
&ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => {
self.tcx.type_of(def_id).instantiate(self.tcx, args).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, args) => {
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, args));
}
ty::Closure(_, args) => {
let args = args.as_closure();
let Some(&f_ty) = args.upvar_tys().get(f.as_usize()) else {
fail_out_of_bounds(self, location);
return;
};
check_equal(self, location, f_ty);
}
&ty::Generator(def_id, args, _) => {
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 {local:?} for {parent_ty:?}"),
);
return;
};
ty::EarlyBinder::bind(f_ty.ty).instantiate(self.tcx, args)
} else {
let Some(&f_ty) = args.as_generator().prefix_tys().get(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));
}
}
}
ProjectionElem::Subtype(ty) => {
if !relate_types(
self.tcx,
self.param_env,
Variance::Covariant,
ty,
place_ref.ty(&self.body.local_decls, self.tcx).ty,
) {
self.fail(
location,
format!(
"Failed subtyping {ty:#?} and {:#?}",
place_ref.ty(&self.body.local_decls, self.tcx).ty
),
)
}
}
_ => {}
}
self.super_projection_elem(place_ref, elem, context, location);
}
fn visit_var_debug_info(&mut self, debuginfo: &VarDebugInfo<'tcx>) {
if let Some(box VarDebugInfoFragment { ty, ref projection }) = debuginfo.composite {
if ty.is_union() || ty.is_enum() {
self.fail(
START_BLOCK.start_location(),
format!("invalid type {ty:?} in debuginfo for {:?}", debuginfo.name),
);
}
if projection.is_empty() {
self.fail(
START_BLOCK.start_location(),
format!("invalid empty projection in debuginfo for {:?}", debuginfo.name),
);
}
if projection.iter().any(|p| !matches!(p, PlaceElem::Field(..))) {
self.fail(
START_BLOCK.start_location(),
format!(
"illegal projection {:?} in debuginfo for {:?}",
projection, debuginfo.name
),
);
}
}
match debuginfo.value {
VarDebugInfoContents::Const(_) => {}
VarDebugInfoContents::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),
);
}
}
}
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!("{place:?}, has deref at the wrong 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, $typat:pat) => {
if !matches!(($t).kind(), $typat) {
self.fail(location, format!($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);
if crate::util::binop_right_homogeneous(*op) {
if let Eq | Lt | Le | Ne | Ge | Gt = op {
// The function pointer types can have lifetimes
if !self.mir_assign_valid_types(a, b) {
self.fail(
location,
format!("Cannot {op:?} compare incompatible types {a:?} and {b:?}"),
);
}
} else if a != b {
self.fail(
location,
format!(
"Cannot perform binary op {op:?} on unequal types {a:?} and {b:?}"
),
);
}
}
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 {op:?} compare type {:?}",
ty::Bool
| ty::Char
| ty::Int(..)
| ty::Uint(..)
| ty::Float(..)
| ty::RawPtr(..)
| ty::FnPtr(..)
)
}
}
AddUnchecked | SubUnchecked | MulUnchecked | Shl | ShlUnchecked | Shr
| ShrUnchecked => {
for x in [a, b] {
check_kinds!(
x,
"Cannot {op:?} non-integer type {:?}",
ty::Uint(..) | ty::Int(..)
)
}
}
BitAnd | BitOr | BitXor => {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform bitwise op {op:?} on type {:?}",
ty::Uint(..) | ty::Int(..) | ty::Bool
)
}
}
Add | Sub | Mul | Div | Rem => {
for x in [a, b] {
check_kinds!(
x,
"Cannot perform arithmetic {op:?} on type {:?}",
ty::Uint(..) | ty::Int(..) | ty::Float(..)
)
}
}
}
}
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 {a:?} and {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::PointerCoercion(_) => {}
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 !self
.tcx
.normalize_erasing_regions(self.param_env, op_ty)
.is_sized(self.tcx, self.param_env)
{
self.fail(
location,
format!("Cannot transmute from non-`Sized` type {op_ty:?}"),
);
}
if !self
.tcx
.normalize_erasing_regions(self.param_env, *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::NullaryOp(NullOp::OffsetOf(fields), container) => {
let fail_out_of_bounds = |this: &mut Self, location, field, ty| {
this.fail(location, format!("Out of bounds field {field:?} for {ty:?}"));
};
let mut current_ty = *container;
for field in fields.iter() {
match current_ty.kind() {
ty::Tuple(fields) => {
let Some(&f_ty) = fields.get(field.as_usize()) else {
fail_out_of_bounds(self, location, field, current_ty);
return;
};
current_ty = self.tcx.normalize_erasing_regions(self.param_env, f_ty);
}
ty::Adt(adt_def, args) => {
if adt_def.is_enum() {
self.fail(
location,
format!("Cannot get field offset from enum {current_ty:?}"),
);
return;
}
let Some(field) = adt_def.non_enum_variant().fields.get(field) else {
fail_out_of_bounds(self, location, field, current_ty);
return;
};
let f_ty = field.ty(self.tcx, args);
current_ty = self.tcx.normalize_erasing_regions(self.param_env, f_ty);
}
_ => {
self.fail(
location,
format!("Cannot get field offset from non-adt type {current_ty:?}"),
);
return;
}
}
}
}
Rvalue::Repeat(_, _)
| Rvalue::ThreadLocalRef(_)
| Rvalue::AddressOf(_, _)
| Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, _)
| 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::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 ({op_cnt_ty:?} != usize)"))
}
}
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 `{kind:?}` is forbidden"));
}
}
StatementKind::StorageLive(_)
| StatementKind::StorageDead(_)
| StatementKind::Coverage(_)
| StatementKind::ConstEvalCounter
| StatementKind::PlaceMention(..)
| StatementKind::Nop => {}
}
self.super_statement(statement, location);
}
fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
match &terminator.kind {
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, _) in targets.iter() {
if Scalar::<()>::try_from_uint(value, size).is_none() {
self.fail(
location,
format!("the value {value:#x} is not a proper {switch_ty:?}"),
)
}
}
}
TerminatorKind::Call { func, .. } => {
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 {func_ty} in `Call` terminator"),
),
}
}
TerminatorKind::Assert { cond, .. } => {
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 {cond_ty} in `Assert` terminator"
),
);
}
}
TerminatorKind::Goto { .. }
| TerminatorKind::Drop { .. }
| TerminatorKind::Yield { .. }
| TerminatorKind::FalseEdge { .. }
| TerminatorKind::FalseUnwind { .. }
| TerminatorKind::InlineAsm { .. }
| TerminatorKind::GeneratorDrop
| TerminatorKind::UnwindResume
| TerminatorKind::UnwindTerminate(_)
| TerminatorKind::Return
| TerminatorKind::Unreachable => {}
}
self.super_terminator(terminator, location);
}
}