1 #![allow(rustc::potential_query_instability)]
2 #![feature(box_patterns)]
3 #![feature(drain_filter)]
4 #![feature(let_chains)]
5 #![feature(map_try_insert)]
6 #![feature(min_specialization)]
7 #![feature(never_type)]
9 #![feature(option_get_or_insert_default)]
10 #![feature(trusted_step)]
11 #![feature(try_blocks)]
12 #![feature(yeet_expr)]
13 #![feature(if_let_guard)]
14 #![recursion_limit = "256"]
19 extern crate rustc_middle;
21 use required_consts::RequiredConstsVisitor;
22 use rustc_const_eval::util;
23 use rustc_data_structures::fx::FxIndexSet;
24 use rustc_data_structures::steal::Steal;
26 use rustc_hir::def_id::{DefId, LocalDefId};
27 use rustc_hir::intravisit::{self, Visitor};
28 use rustc_index::vec::IndexVec;
29 use rustc_middle::mir::visit::Visitor as _;
30 use rustc_middle::mir::{
31 traversal, AnalysisPhase, Body, ConstQualifs, Constant, LocalDecl, MirPass, MirPhase, Operand,
32 Place, ProjectionElem, Promoted, RuntimePhase, Rvalue, SourceInfo, Statement, StatementKind,
35 use rustc_middle::ty::query::Providers;
36 use rustc_middle::ty::{self, TyCtxt, TypeVisitable};
42 use pass_manager::{self as pm, Lint, MirLint, WithMinOptLevel};
44 mod abort_unwinding_calls;
46 mod add_moves_for_packed_drops;
48 mod check_const_item_mutation;
50 pub mod check_unsafety;
51 // This pass is public to allow external drivers to perform MIR cleanup
52 pub mod cleanup_post_borrowck;
58 mod dataflow_const_prop;
59 mod dead_store_elimination;
61 mod deduce_param_attrs;
62 mod deduplicate_blocks;
66 mod early_otherwise_branch;
67 mod elaborate_box_derefs;
70 mod function_item_references;
77 mod multiple_return_terminators;
78 mod normalize_array_len;
80 // This pass is public to allow external drivers to perform MIR cleanup
81 pub mod remove_false_edges;
82 mod remove_noop_landing_pads;
83 mod remove_storage_markers;
84 mod remove_uninit_drops;
85 mod remove_unneeded_drops;
89 mod separate_const_switch;
91 // This pass is public to allow external drivers to perform MIR cleanup
93 mod simplify_branches;
94 mod simplify_comparison_integral;
97 mod uninhabited_enum_branching;
100 use rustc_const_eval::transform::check_consts::{self, ConstCx};
101 use rustc_const_eval::transform::promote_consts;
102 use rustc_const_eval::transform::validate;
103 use rustc_mir_dataflow::rustc_peek;
105 pub fn provide(providers: &mut Providers) {
106 check_unsafety::provide(providers);
107 check_packed_ref::provide(providers);
108 coverage::query::provide(providers);
109 ffi_unwind_calls::provide(providers);
110 shim::provide(providers);
111 *providers = Providers {
114 mir_const_qualif: |tcx, def_id| {
115 let def_id = def_id.expect_local();
116 if let Some(def) = ty::WithOptConstParam::try_lookup(def_id, tcx) {
117 tcx.mir_const_qualif_const_arg(def)
119 mir_const_qualif(tcx, ty::WithOptConstParam::unknown(def_id))
122 mir_const_qualif_const_arg: |tcx, (did, param_did)| {
123 mir_const_qualif(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
126 mir_drops_elaborated_and_const_checked,
128 mir_for_ctfe_of_const_arg,
131 is_ctfe_mir_available: |tcx, did| is_mir_available(tcx, did),
132 mir_callgraph_reachable: inline::cycle::mir_callgraph_reachable,
133 mir_inliner_callees: inline::cycle::mir_inliner_callees,
134 promoted_mir: |tcx, def_id| {
135 let def_id = def_id.expect_local();
136 if let Some(def) = ty::WithOptConstParam::try_lookup(def_id, tcx) {
137 tcx.promoted_mir_of_const_arg(def)
139 promoted_mir(tcx, ty::WithOptConstParam::unknown(def_id))
142 promoted_mir_of_const_arg: |tcx, (did, param_did)| {
143 promoted_mir(tcx, ty::WithOptConstParam { did, const_param_did: Some(param_did) })
145 deduced_param_attrs: deduce_param_attrs::deduced_param_attrs,
150 fn remap_mir_for_const_eval_select<'tcx>(
152 mut body: Body<'tcx>,
153 context: hir::Constness,
155 for bb in body.basic_blocks.as_mut().iter_mut() {
156 let terminator = bb.terminator.as_mut().expect("invalid terminator");
157 match terminator.kind {
158 TerminatorKind::Call {
159 func: Operand::Constant(box Constant { ref literal, .. }),
166 } if let ty::FnDef(def_id, _) = *literal.ty().kind()
167 && tcx.item_name(def_id) == sym::const_eval_select
168 && tcx.is_intrinsic(def_id) =>
170 let [tupled_args, called_in_const, called_at_rt]: [_; 3] = std::mem::take(args).try_into().unwrap();
171 let ty = tupled_args.ty(&body.local_decls, tcx);
172 let fields = ty.tuple_fields();
173 let num_args = fields.len();
174 let func = if context == hir::Constness::Const { called_in_const } else { called_at_rt };
175 let (method, place): (fn(Place<'tcx>) -> Operand<'tcx>, Place<'tcx>) = match tupled_args {
176 Operand::Constant(_) => {
177 // there is no good way of extracting a tuple arg from a constant (const generic stuff)
178 // so we just create a temporary and deconstruct that.
179 let local = body.local_decls.push(LocalDecl::new(ty, fn_span));
180 bb.statements.push(Statement {
181 source_info: SourceInfo::outermost(fn_span),
182 kind: StatementKind::Assign(Box::new((local.into(), Rvalue::Use(tupled_args.clone())))),
184 (Operand::Move, local.into())
186 Operand::Move(place) => (Operand::Move, place),
187 Operand::Copy(place) => (Operand::Copy, place),
189 let place_elems = place.projection;
190 let arguments = (0..num_args).map(|x| {
191 let mut place_elems = place_elems.to_vec();
192 place_elems.push(ProjectionElem::Field(x.into(), fields[x]));
193 let projection = tcx.intern_place_elems(&place_elems);
200 terminator.kind = TerminatorKind::Call { func, args: arguments, destination, target, cleanup, from_hir_call: false, fn_span };
208 fn is_mir_available(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
209 let def_id = def_id.expect_local();
210 tcx.mir_keys(()).contains(&def_id)
213 /// Finds the full set of `DefId`s within the current crate that have
214 /// MIR associated with them.
215 fn mir_keys(tcx: TyCtxt<'_>, (): ()) -> FxIndexSet<LocalDefId> {
216 let mut set = FxIndexSet::default();
218 // All body-owners have MIR associated with them.
219 set.extend(tcx.hir().body_owners());
221 // Additionally, tuple struct/variant constructors have MIR, but
222 // they don't have a BodyId, so we need to build them separately.
223 struct GatherCtors<'a> {
224 set: &'a mut FxIndexSet<LocalDefId>,
226 impl<'tcx> Visitor<'tcx> for GatherCtors<'_> {
227 fn visit_variant_data(&mut self, v: &'tcx hir::VariantData<'tcx>) {
228 if let hir::VariantData::Tuple(_, _, def_id) = *v {
229 self.set.insert(def_id);
231 intravisit::walk_struct_def(self, v)
234 tcx.hir().visit_all_item_likes_in_crate(&mut GatherCtors { set: &mut set });
239 fn mir_const_qualif(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> ConstQualifs {
240 let const_kind = tcx.hir().body_const_context(def.did);
242 // No need to const-check a non-const `fn`.
243 if const_kind.is_none() {
244 return Default::default();
247 // N.B., this `borrow()` is guaranteed to be valid (i.e., the value
248 // cannot yet be stolen), because `mir_promoted()`, which steals
249 // from `mir_const(), forces this query to execute before
250 // performing the steal.
251 let body = &tcx.mir_const(def).borrow();
253 if body.return_ty().references_error() {
254 tcx.sess.delay_span_bug(body.span, "mir_const_qualif: MIR had errors");
255 return Default::default();
258 let ccx = check_consts::ConstCx { body, tcx, const_kind, param_env: tcx.param_env(def.did) };
260 let mut validator = check_consts::check::Checker::new(&ccx);
261 validator.check_body();
263 // We return the qualifs in the return place for every MIR body, even though it is only used
264 // when deciding to promote a reference to a `const` for now.
265 validator.qualifs_in_return_place()
268 /// Make MIR ready for const evaluation. This is run on all MIR, not just on consts!
269 /// FIXME(oli-obk): it's unclear whether we still need this phase (and its corresponding query).
270 /// We used to have this for pre-miri MIR based const eval.
273 def: ty::WithOptConstParam<LocalDefId>,
274 ) -> &'tcx Steal<Body<'tcx>> {
275 if let Some(def) = def.try_upgrade(tcx) {
276 return tcx.mir_const(def);
279 // Unsafety check uses the raw mir, so make sure it is run.
280 if !tcx.sess.opts.unstable_opts.thir_unsafeck {
281 if let Some(param_did) = def.const_param_did {
282 tcx.ensure().unsafety_check_result_for_const_arg((def.did, param_did));
284 tcx.ensure().unsafety_check_result(def.did);
288 // has_ffi_unwind_calls query uses the raw mir, so make sure it is run.
289 tcx.ensure().has_ffi_unwind_calls(def.did);
291 let mut body = tcx.mir_built(def).steal();
293 pass_manager::dump_mir_for_phase_change(tcx, &body);
300 &Lint(check_packed_ref::CheckPackedRef),
301 &Lint(check_const_item_mutation::CheckConstItemMutation),
302 &Lint(function_item_references::FunctionItemReferences),
303 // What we need to do constant evaluation.
304 &simplify::SimplifyCfg::new("initial"),
305 &rustc_peek::SanityCheck, // Just a lint
309 tcx.alloc_steal_mir(body)
312 /// Compute the main MIR body and the list of MIR bodies of the promoteds.
313 fn mir_promoted<'tcx>(
315 def: ty::WithOptConstParam<LocalDefId>,
316 ) -> (&'tcx Steal<Body<'tcx>>, &'tcx Steal<IndexVec<Promoted, Body<'tcx>>>) {
317 if let Some(def) = def.try_upgrade(tcx) {
318 return tcx.mir_promoted(def);
321 // Ensure that we compute the `mir_const_qualif` for constants at
322 // this point, before we steal the mir-const result.
323 // Also this means promotion can rely on all const checks having been done.
324 let const_qualifs = tcx.mir_const_qualif_opt_const_arg(def);
325 let mut body = tcx.mir_const(def).steal();
326 if let Some(error_reported) = const_qualifs.tainted_by_errors {
327 body.tainted_by_errors = Some(error_reported);
330 let mut required_consts = Vec::new();
331 let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
332 for (bb, bb_data) in traversal::reverse_postorder(&body) {
333 required_consts_visitor.visit_basic_block_data(bb, bb_data);
335 body.required_consts = required_consts;
337 // What we need to run borrowck etc.
338 let promote_pass = promote_consts::PromoteTemps::default();
344 &simplify::SimplifyCfg::new("promote-consts"),
345 &coverage::InstrumentCoverage,
347 Some(MirPhase::Analysis(AnalysisPhase::Initial)),
350 let promoted = promote_pass.promoted_fragments.into_inner();
351 (tcx.alloc_steal_mir(body), tcx.alloc_steal_promoted(promoted))
354 /// Compute the MIR that is used during CTFE (and thus has no optimizations run on it)
355 fn mir_for_ctfe<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> &'tcx Body<'tcx> {
356 let did = def_id.expect_local();
357 if let Some(def) = ty::WithOptConstParam::try_lookup(did, tcx) {
358 tcx.mir_for_ctfe_of_const_arg(def)
360 tcx.arena.alloc(inner_mir_for_ctfe(tcx, ty::WithOptConstParam::unknown(did)))
364 /// Same as `mir_for_ctfe`, but used to get the MIR of a const generic parameter.
365 /// The docs on `WithOptConstParam` explain this a bit more, but the TLDR is that
366 /// we'd get cycle errors with `mir_for_ctfe`, because typeck would need to typeck
367 /// the const parameter while type checking the main body, which in turn would try
368 /// to type check the main body again.
369 fn mir_for_ctfe_of_const_arg<'tcx>(
371 (did, param_did): (LocalDefId, DefId),
372 ) -> &'tcx Body<'tcx> {
373 tcx.arena.alloc(inner_mir_for_ctfe(
375 ty::WithOptConstParam { did, const_param_did: Some(param_did) },
379 fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_> {
380 // FIXME: don't duplicate this between the optimized_mir/mir_for_ctfe queries
381 if tcx.is_constructor(def.did.to_def_id()) {
382 // There's no reason to run all of the MIR passes on constructors when
383 // we can just output the MIR we want directly. This also saves const
384 // qualification and borrow checking the trouble of special casing
386 return shim::build_adt_ctor(tcx, def.did.to_def_id());
391 .body_const_context(def.did)
392 .expect("mir_for_ctfe should not be used for runtime functions");
394 let body = tcx.mir_drops_elaborated_and_const_checked(def).borrow().clone();
396 let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::Const);
399 // Do not const prop functions, either they get executed at runtime or exported to metadata,
400 // so we run const prop on them, or they don't, in which case we const evaluate some control
401 // flow paths of the function and any errors in those paths will get emitted as const eval
403 hir::ConstContext::ConstFn => {}
404 // Static items always get evaluated, so we can just let const eval see if any erroneous
405 // control flow paths get executed.
406 hir::ConstContext::Static(_) => {}
407 // Associated constants get const prop run so we detect common failure situations in the
408 // crate that defined the constant.
409 // Technically we want to not run on regular const items, but oli-obk doesn't know how to
410 // conveniently detect that at this point without looking at the HIR.
411 hir::ConstContext::Const => {
415 &[&const_prop::ConstProp],
416 Some(MirPhase::Runtime(RuntimePhase::Optimized)),
421 debug_assert!(!body.has_free_regions(), "Free regions in MIR for CTFE");
426 /// Obtain just the main MIR (no promoteds) and run some cleanups on it. This also runs
427 /// mir borrowck *before* doing so in order to ensure that borrowck can be run and doesn't
428 /// end up missing the source MIR due to stealing happening.
429 fn mir_drops_elaborated_and_const_checked<'tcx>(
431 def: ty::WithOptConstParam<LocalDefId>,
432 ) -> &'tcx Steal<Body<'tcx>> {
433 if let Some(def) = def.try_upgrade(tcx) {
434 return tcx.mir_drops_elaborated_and_const_checked(def);
437 let mir_borrowck = tcx.mir_borrowck_opt_const_arg(def);
439 let is_fn_like = tcx.def_kind(def.did).is_fn_like();
441 let did = def.did.to_def_id();
442 let def = ty::WithOptConstParam::unknown(did);
444 // Do not compute the mir call graph without said call graph actually being used.
445 if inline::Inline.is_enabled(&tcx.sess) {
446 let _ = tcx.mir_inliner_callees(ty::InstanceDef::Item(def));
450 let (body, _) = tcx.mir_promoted(def);
451 let mut body = body.steal();
452 if let Some(error_reported) = mir_borrowck.tainted_by_errors {
453 body.tainted_by_errors = Some(error_reported);
456 run_analysis_to_runtime_passes(tcx, &mut body);
458 tcx.alloc_steal_mir(body)
461 fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
462 assert!(body.phase == MirPhase::Analysis(AnalysisPhase::Initial));
463 let did = body.source.def_id();
465 debug!("analysis_mir_cleanup({:?})", did);
466 run_analysis_cleanup_passes(tcx, body);
467 assert!(body.phase == MirPhase::Analysis(AnalysisPhase::PostCleanup));
469 // Do a little drop elaboration before const-checking if `const_precise_live_drops` is enabled.
470 if check_consts::post_drop_elaboration::checking_enabled(&ConstCx::new(tcx, &body)) {
475 &remove_uninit_drops::RemoveUninitDrops,
476 &simplify::SimplifyCfg::new("remove-false-edges"),
480 check_consts::post_drop_elaboration::check_live_drops(tcx, &body); // FIXME: make this a MIR lint
483 debug!("runtime_mir_lowering({:?})", did);
484 run_runtime_lowering_passes(tcx, body);
485 assert!(body.phase == MirPhase::Runtime(RuntimePhase::Initial));
487 debug!("runtime_mir_cleanup({:?})", did);
488 run_runtime_cleanup_passes(tcx, body);
489 assert!(body.phase == MirPhase::Runtime(RuntimePhase::PostCleanup));
492 // FIXME(JakobDegen): Can we make these lists of passes consts?
494 /// After this series of passes, no lifetime analysis based on borrowing can be done.
495 fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
496 let passes: &[&dyn MirPass<'tcx>] = &[
497 &remove_false_edges::RemoveFalseEdges,
498 &simplify_branches::SimplifyConstCondition::new("initial"),
499 &remove_noop_landing_pads::RemoveNoopLandingPads,
500 &cleanup_post_borrowck::CleanupNonCodegenStatements,
501 &simplify::SimplifyCfg::new("early-opt"),
502 &deref_separator::Derefer,
505 pm::run_passes(tcx, body, passes, Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)));
508 /// Returns the sequence of passes that lowers analysis to runtime MIR.
509 fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
510 let passes: &[&dyn MirPass<'tcx>] = &[
511 // These next passes must be executed together
512 &add_call_guards::CriticalCallEdges,
513 &elaborate_drops::ElaborateDrops,
514 // This will remove extraneous landing pads which are no longer
515 // necessary as well as well as forcing any call in a non-unwinding
516 // function calling a possibly-unwinding function to abort the process.
517 &abort_unwinding_calls::AbortUnwindingCalls,
518 // AddMovesForPackedDrops needs to run after drop
520 &add_moves_for_packed_drops::AddMovesForPackedDrops,
521 // `AddRetag` needs to run after `ElaborateDrops`. Otherwise it should run fairly late,
522 // but before optimizations begin.
523 &elaborate_box_derefs::ElaborateBoxDerefs,
524 &generator::StateTransform,
525 &add_retag::AddRetag,
526 // Deaggregator is necessary for const prop. We may want to consider implementing
527 // CTFE support for aggregates.
528 &deaggregator::Deaggregator,
529 &Lint(const_prop_lint::ConstProp),
531 pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
534 /// Returns the sequence of passes that do the initial cleanup of runtime MIR.
535 fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
536 let passes: &[&dyn MirPass<'tcx>] = &[
537 &elaborate_box_derefs::ElaborateBoxDerefs,
538 &lower_intrinsics::LowerIntrinsics,
539 &simplify::SimplifyCfg::new("elaborate-drops"),
542 pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));
545 fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
546 fn o1<T>(x: T) -> WithMinOptLevel<T> {
547 WithMinOptLevel(1, x)
550 // The main optimizations that we do on MIR.
555 &reveal_all::RevealAll, // has to be done before inlining, since inlined code is in RevealAll mode.
556 &lower_slice_len::LowerSliceLenCalls, // has to be done before inlining, otherwise actual call will be almost always inlined. Also simple, so can just do first
557 &normalize_array_len::NormalizeArrayLen, // has to run after `slice::len` lowering
558 &unreachable_prop::UnreachablePropagation,
559 &uninhabited_enum_branching::UninhabitedEnumBranching,
560 &o1(simplify::SimplifyCfg::new("after-uninhabited-enum-branching")),
562 &remove_storage_markers::RemoveStorageMarkers,
563 &remove_zsts::RemoveZsts,
564 &const_goto::ConstGoto,
565 &remove_unneeded_drops::RemoveUnneededDrops,
566 &sroa::ScalarReplacementOfAggregates,
567 &match_branches::MatchBranchSimplification,
568 // inst combine is after MatchBranchSimplification to clean up Ne(_1, false)
569 &multiple_return_terminators::MultipleReturnTerminators,
570 &instcombine::InstCombine,
571 &separate_const_switch::SeparateConstSwitch,
573 // FIXME(#70073): This pass is responsible for both optimization as well as some lints.
574 &const_prop::ConstProp,
575 &dataflow_const_prop::DataflowConstProp,
577 // Const-prop runs unconditionally, but doesn't mutate the MIR at mir-opt-level=0.
578 &const_debuginfo::ConstDebugInfo,
579 &o1(simplify_branches::SimplifyConstCondition::new("after-const-prop")),
580 &early_otherwise_branch::EarlyOtherwiseBranch,
581 &simplify_comparison_integral::SimplifyComparisonIntegral,
582 &simplify_try::SimplifyArmIdentity,
583 &simplify_try::SimplifyBranchSame,
584 &dead_store_elimination::DeadStoreElimination,
585 &dest_prop::DestinationPropagation,
586 &o1(simplify_branches::SimplifyConstCondition::new("final")),
587 &o1(remove_noop_landing_pads::RemoveNoopLandingPads),
588 &o1(simplify::SimplifyCfg::new("final")),
589 &nrvo::RenameReturnPlace,
590 &simplify::SimplifyLocals,
591 &multiple_return_terminators::MultipleReturnTerminators,
592 &deduplicate_blocks::DeduplicateBlocks,
593 // Some cleanup necessary at least for LLVM and potentially other codegen backends.
594 &add_call_guards::CriticalCallEdges,
595 // Dump the end result for testing and debugging purposes.
596 &dump_mir::Marker("PreCodegen"),
598 Some(MirPhase::Runtime(RuntimePhase::Optimized)),
602 /// Optimize the MIR and prepare it for codegen.
603 fn optimized_mir<'tcx>(tcx: TyCtxt<'tcx>, did: DefId) -> &'tcx Body<'tcx> {
604 let did = did.expect_local();
605 assert_eq!(ty::WithOptConstParam::try_lookup(did, tcx), None);
606 tcx.arena.alloc(inner_optimized_mir(tcx, did))
609 fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
610 if tcx.is_constructor(did.to_def_id()) {
611 // There's no reason to run all of the MIR passes on constructors when
612 // we can just output the MIR we want directly. This also saves const
613 // qualification and borrow checking the trouble of special casing
615 return shim::build_adt_ctor(tcx, did.to_def_id());
618 match tcx.hir().body_const_context(did) {
619 // Run the `mir_for_ctfe` query, which depends on `mir_drops_elaborated_and_const_checked`
620 // which we are going to steal below. Thus we need to run `mir_for_ctfe` first, so it
621 // computes and caches its result.
622 Some(hir::ConstContext::ConstFn) => tcx.ensure().mir_for_ctfe(did),
624 Some(other) => panic!("do not use `optimized_mir` for constants: {:?}", other),
626 debug!("about to call mir_drops_elaborated...");
628 tcx.mir_drops_elaborated_and_const_checked(ty::WithOptConstParam::unknown(did)).steal();
629 let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::NotConst);
630 debug!("body: {:#?}", body);
631 run_optimization_passes(tcx, &mut body);
633 debug_assert!(!body.has_free_regions(), "Free regions in optimized MIR");
638 /// Fetch all the promoteds of an item and prepare their MIR bodies to be ready for
639 /// constant evaluation once all substitutions become known.
640 fn promoted_mir<'tcx>(
642 def: ty::WithOptConstParam<LocalDefId>,
643 ) -> &'tcx IndexVec<Promoted, Body<'tcx>> {
644 if tcx.is_constructor(def.did.to_def_id()) {
645 return tcx.arena.alloc(IndexVec::new());
648 let tainted_by_errors = tcx.mir_borrowck_opt_const_arg(def).tainted_by_errors;
649 let mut promoted = tcx.mir_promoted(def).1.steal();
651 for body in &mut promoted {
652 if let Some(error_reported) = tainted_by_errors {
653 body.tainted_by_errors = Some(error_reported);
655 run_analysis_to_runtime_passes(tcx, body);
658 debug_assert!(!promoted.has_free_regions(), "Free regions in promoted MIR");
660 tcx.arena.alloc(promoted)