use rustc_ast::MetaItem;
use rustc_hir::def_id::DefId;
use rustc_index::bit_set::BitSet;
use rustc_middle::mir::{self, Body, Local, Location, MirPass};
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_span::symbol::{sym, Symbol};
use rustc_span::Span;
use tracing::{debug, info};
use crate::errors::{
PeekArgumentNotALocal, PeekArgumentUntracked, PeekBitNotSet, PeekMustBeNotTemporary,
PeekMustBePlaceOrRefPlace, StopAfterDataFlowEndedCompilation,
};
use crate::framework::BitSetExt;
use crate::impls::{
DefinitelyInitializedPlaces, MaybeInitializedPlaces, MaybeLiveLocals, MaybeUninitializedPlaces,
};
use crate::move_paths::{HasMoveData, LookupResult, MoveData, MovePathIndex};
use crate::{Analysis, JoinSemiLattice, ResultsCursor};
pub struct SanityCheck;
fn has_rustc_mir_with(tcx: TyCtxt<'_>, def_id: DefId, name: Symbol) -> Option<MetaItem> {
for attr in tcx.get_attrs(def_id, sym::rustc_mir) {
let items = attr.meta_item_list();
for item in items.iter().flat_map(|l| l.iter()) {
match item.meta_item() {
Some(mi) if mi.has_name(name) => return Some(mi.clone()),
_ => continue,
}
}
}
None
}
impl<'tcx> MirPass<'tcx> for SanityCheck {
fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
let def_id = body.source.def_id();
if !tcx.has_attr(def_id, sym::rustc_mir) {
debug!("skipping rustc_peek::SanityCheck on {}", tcx.def_path_str(def_id));
return;
} else {
debug!("running rustc_peek::SanityCheck on {}", tcx.def_path_str(def_id));
}
let param_env = tcx.param_env(def_id);
let move_data = MoveData::gather_moves(body, tcx, param_env, |_| true);
if has_rustc_mir_with(tcx, def_id, sym::rustc_peek_maybe_init).is_some() {
let flow_inits = MaybeInitializedPlaces::new(tcx, body, &move_data)
.into_engine(tcx, body)
.iterate_to_fixpoint();
sanity_check_via_rustc_peek(tcx, flow_inits.into_results_cursor(body));
}
if has_rustc_mir_with(tcx, def_id, sym::rustc_peek_maybe_uninit).is_some() {
let flow_uninits = MaybeUninitializedPlaces::new(tcx, body, &move_data)
.into_engine(tcx, body)
.iterate_to_fixpoint();
sanity_check_via_rustc_peek(tcx, flow_uninits.into_results_cursor(body));
}
if has_rustc_mir_with(tcx, def_id, sym::rustc_peek_definite_init).is_some() {
let flow_def_inits = DefinitelyInitializedPlaces::new(body, &move_data)
.into_engine(tcx, body)
.iterate_to_fixpoint();
sanity_check_via_rustc_peek(tcx, flow_def_inits.into_results_cursor(body));
}
if has_rustc_mir_with(tcx, def_id, sym::rustc_peek_liveness).is_some() {
let flow_liveness = MaybeLiveLocals.into_engine(tcx, body).iterate_to_fixpoint();
sanity_check_via_rustc_peek(tcx, flow_liveness.into_results_cursor(body));
}
if has_rustc_mir_with(tcx, def_id, sym::stop_after_dataflow).is_some() {
tcx.dcx().emit_fatal(StopAfterDataFlowEndedCompilation);
}
}
}
fn sanity_check_via_rustc_peek<'tcx, A>(tcx: TyCtxt<'tcx>, mut cursor: ResultsCursor<'_, 'tcx, A>)
where
A: RustcPeekAt<'tcx>,
{
let def_id = cursor.body().source.def_id();
debug!("sanity_check_via_rustc_peek def_id: {:?}", def_id);
let peek_calls = cursor.body().basic_blocks.iter_enumerated().filter_map(|(bb, block_data)| {
PeekCall::from_terminator(tcx, block_data.terminator()).map(|call| (bb, block_data, call))
});
for (bb, block_data, call) in peek_calls {
let (statement_index, peek_rval) = block_data
.statements
.iter()
.enumerate()
.find_map(|(i, stmt)| value_assigned_to_local(stmt, call.arg).map(|rval| (i, rval)))
.expect(
"call to rustc_peek should be preceded by \
assignment to temporary holding its argument",
);
match (call.kind, peek_rval) {
(PeekCallKind::ByRef, mir::Rvalue::Ref(_, _, place))
| (
PeekCallKind::ByVal,
mir::Rvalue::Use(mir::Operand::Move(place) | mir::Operand::Copy(place)),
) => {
let loc = Location { block: bb, statement_index };
cursor.seek_before_primary_effect(loc);
let state = cursor.get();
let analysis = cursor.analysis();
analysis.peek_at(tcx, *place, state, call);
}
_ => {
tcx.dcx().emit_err(PeekMustBePlaceOrRefPlace { span: call.span });
}
}
}
}
fn value_assigned_to_local<'a, 'tcx>(
stmt: &'a mir::Statement<'tcx>,
local: Local,
) -> Option<&'a mir::Rvalue<'tcx>> {
if let mir::StatementKind::Assign(box (place, rvalue)) = &stmt.kind {
if let Some(l) = place.as_local() {
if local == l {
return Some(&*rvalue);
}
}
}
None
}
#[derive(Clone, Copy, Debug)]
enum PeekCallKind {
ByVal,
ByRef,
}
impl PeekCallKind {
fn from_arg_ty(arg: Ty<'_>) -> Self {
match arg.kind() {
ty::Ref(_, _, _) => PeekCallKind::ByRef,
_ => PeekCallKind::ByVal,
}
}
}
#[derive(Clone, Copy, Debug)]
struct PeekCall {
arg: Local,
kind: PeekCallKind,
span: Span,
}
impl PeekCall {
fn from_terminator<'tcx>(
tcx: TyCtxt<'tcx>,
terminator: &mir::Terminator<'tcx>,
) -> Option<Self> {
use mir::Operand;
let span = terminator.source_info.span;
if let mir::TerminatorKind::Call { func: Operand::Constant(func), args, .. } =
&terminator.kind
{
if let ty::FnDef(def_id, fn_args) = *func.const_.ty().kind() {
if tcx.intrinsic(def_id)?.name != sym::rustc_peek {
return None;
}
assert_eq!(fn_args.len(), 1);
let kind = PeekCallKind::from_arg_ty(fn_args.type_at(0));
let arg = match &args[0].node {
Operand::Copy(place) | Operand::Move(place) => {
if let Some(local) = place.as_local() {
local
} else {
tcx.dcx().emit_err(PeekMustBeNotTemporary { span });
return None;
}
}
_ => {
tcx.dcx().emit_err(PeekMustBeNotTemporary { span });
return None;
}
};
return Some(PeekCall { arg, kind, span });
}
}
None
}
}
trait RustcPeekAt<'tcx>: Analysis<'tcx> {
fn peek_at(
&self,
tcx: TyCtxt<'tcx>,
place: mir::Place<'tcx>,
flow_state: &Self::Domain,
call: PeekCall,
);
}
impl<'tcx, A, D> RustcPeekAt<'tcx> for A
where
A: Analysis<'tcx, Domain = D> + HasMoveData<'tcx>,
D: JoinSemiLattice + Clone + BitSetExt<MovePathIndex>,
{
fn peek_at(
&self,
tcx: TyCtxt<'tcx>,
place: mir::Place<'tcx>,
flow_state: &Self::Domain,
call: PeekCall,
) {
match self.move_data().rev_lookup.find(place.as_ref()) {
LookupResult::Exact(peek_mpi) => {
let bit_state = flow_state.contains(peek_mpi);
debug!("rustc_peek({:?} = &{:?}) bit_state: {}", call.arg, place, bit_state);
if !bit_state {
tcx.dcx().emit_err(PeekBitNotSet { span: call.span });
}
}
LookupResult::Parent(..) => {
tcx.dcx().emit_err(PeekArgumentUntracked { span: call.span });
}
}
}
}
impl<'tcx> RustcPeekAt<'tcx> for MaybeLiveLocals {
fn peek_at(
&self,
tcx: TyCtxt<'tcx>,
place: mir::Place<'tcx>,
flow_state: &BitSet<Local>,
call: PeekCall,
) {
info!(?place, "peek_at");
let Some(local) = place.as_local() else {
tcx.dcx().emit_err(PeekArgumentNotALocal { span: call.span });
return;
};
if !flow_state.contains(local) {
tcx.dcx().emit_err(PeekBitNotSet { span: call.span });
}
}
}