| use crate::{shim, util}; |
| use required_consts::RequiredConstsVisitor; |
| use rustc_data_structures::fx::FxHashSet; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LOCAL_CRATE}; |
| use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor}; |
| use rustc_index::vec::IndexVec; |
| use rustc_middle::mir::visit::Visitor as _; |
| use rustc_middle::mir::{traversal, Body, ConstQualifs, MirPhase, Promoted}; |
| use rustc_middle::ty::query::Providers; |
| use rustc_middle::ty::steal::Steal; |
| use rustc_middle::ty::{InstanceDef, TyCtxt, TypeFoldable}; |
| use rustc_span::{Span, Symbol}; |
| use std::borrow::Cow; |
| |
| pub mod add_call_guards; |
| pub mod add_moves_for_packed_drops; |
| pub mod add_retag; |
| pub mod check_consts; |
| pub mod check_packed_ref; |
| pub mod check_unsafety; |
| pub mod cleanup_post_borrowck; |
| pub mod const_prop; |
| pub mod copy_prop; |
| pub mod deaggregator; |
| pub mod dump_mir; |
| pub mod elaborate_drops; |
| pub mod generator; |
| pub mod inline; |
| pub mod instcombine; |
| pub mod instrument_coverage; |
| pub mod no_landing_pads; |
| pub mod nrvo; |
| pub mod promote_consts; |
| pub mod qualify_min_const_fn; |
| pub mod remove_noop_landing_pads; |
| pub mod required_consts; |
| pub mod rustc_peek; |
| pub mod simplify; |
| pub mod simplify_branches; |
| pub mod simplify_try; |
| pub mod uninhabited_enum_branching; |
| pub mod unreachable_prop; |
| pub mod validate; |
| |
| pub(crate) fn provide(providers: &mut Providers) { |
| self::check_unsafety::provide(providers); |
| *providers = Providers { |
| mir_keys, |
| mir_const, |
| mir_const_qualif, |
| mir_validated, |
| mir_drops_elaborated_and_const_checked, |
| optimized_mir, |
| is_mir_available, |
| promoted_mir, |
| ..*providers |
| }; |
| instrument_coverage::provide(providers); |
| } |
| |
| fn is_mir_available(tcx: TyCtxt<'_>, def_id: DefId) -> bool { |
| tcx.mir_keys(def_id.krate).contains(&def_id.expect_local()) |
| } |
| |
| /// Finds the full set of `DefId`s within the current crate that have |
| /// MIR associated with them. |
| fn mir_keys(tcx: TyCtxt<'_>, krate: CrateNum) -> FxHashSet<LocalDefId> { |
| assert_eq!(krate, LOCAL_CRATE); |
| |
| let mut set = FxHashSet::default(); |
| |
| // All body-owners have MIR associated with them. |
| set.extend(tcx.body_owners()); |
| |
| // Additionally, tuple struct/variant constructors have MIR, but |
| // they don't have a BodyId, so we need to build them separately. |
| struct GatherCtors<'a, 'tcx> { |
| tcx: TyCtxt<'tcx>, |
| set: &'a mut FxHashSet<LocalDefId>, |
| } |
| impl<'a, 'tcx> Visitor<'tcx> for GatherCtors<'a, 'tcx> { |
| fn visit_variant_data( |
| &mut self, |
| v: &'tcx hir::VariantData<'tcx>, |
| _: Symbol, |
| _: &'tcx hir::Generics<'tcx>, |
| _: hir::HirId, |
| _: Span, |
| ) { |
| if let hir::VariantData::Tuple(_, hir_id) = *v { |
| self.set.insert(self.tcx.hir().local_def_id(hir_id)); |
| } |
| intravisit::walk_struct_def(self, v) |
| } |
| type Map = intravisit::ErasedMap<'tcx>; |
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { |
| NestedVisitorMap::None |
| } |
| } |
| tcx.hir() |
| .krate() |
| .visit_all_item_likes(&mut GatherCtors { tcx, set: &mut set }.as_deep_visitor()); |
| |
| set |
| } |
| |
| /// Where a specific `mir::Body` comes from. |
| #[derive(Debug, Copy, Clone)] |
| pub struct MirSource<'tcx> { |
| pub instance: InstanceDef<'tcx>, |
| |
| /// If `Some`, this is a promoted rvalue within the parent function. |
| pub promoted: Option<Promoted>, |
| } |
| |
| impl<'tcx> MirSource<'tcx> { |
| pub fn item(def_id: DefId) -> Self { |
| MirSource { instance: InstanceDef::Item(def_id), promoted: None } |
| } |
| |
| #[inline] |
| pub fn def_id(&self) -> DefId { |
| self.instance.def_id() |
| } |
| } |
| |
| /// Generates a default name for the pass based on the name of the |
| /// type `T`. |
| pub fn default_name<T: ?Sized>() -> Cow<'static, str> { |
| let name = ::std::any::type_name::<T>(); |
| if let Some(tail) = name.rfind(':') { Cow::from(&name[tail + 1..]) } else { Cow::from(name) } |
| } |
| |
| /// A streamlined trait that you can implement to create a pass; the |
| /// pass will be named after the type, and it will consist of a main |
| /// loop that goes over each available MIR and applies `run_pass`. |
| pub trait MirPass<'tcx> { |
| fn name(&self) -> Cow<'_, str> { |
| default_name::<Self>() |
| } |
| |
| fn run_pass(&self, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>); |
| } |
| |
| pub fn run_passes( |
| tcx: TyCtxt<'tcx>, |
| body: &mut Body<'tcx>, |
| instance: InstanceDef<'tcx>, |
| promoted: Option<Promoted>, |
| mir_phase: MirPhase, |
| passes: &[&[&dyn MirPass<'tcx>]], |
| ) { |
| let phase_index = mir_phase.phase_index(); |
| let source = MirSource { instance, promoted }; |
| let validate = tcx.sess.opts.debugging_opts.validate_mir; |
| |
| if body.phase >= mir_phase { |
| return; |
| } |
| |
| if validate { |
| validate::Validator { when: format!("input to phase {:?}", mir_phase) } |
| .run_pass(tcx, source, body); |
| } |
| |
| let mut index = 0; |
| let mut run_pass = |pass: &dyn MirPass<'tcx>| { |
| let run_hooks = |body: &_, index, is_after| { |
| dump_mir::on_mir_pass( |
| tcx, |
| &format_args!("{:03}-{:03}", phase_index, index), |
| &pass.name(), |
| source, |
| body, |
| is_after, |
| ); |
| }; |
| run_hooks(body, index, false); |
| pass.run_pass(tcx, source, body); |
| run_hooks(body, index, true); |
| |
| if validate { |
| validate::Validator { when: format!("after {} in phase {:?}", pass.name(), mir_phase) } |
| .run_pass(tcx, source, body); |
| } |
| |
| index += 1; |
| }; |
| |
| for pass_group in passes { |
| for pass in *pass_group { |
| run_pass(*pass); |
| } |
| } |
| |
| body.phase = mir_phase; |
| |
| if mir_phase == MirPhase::Optimized { |
| validate::Validator { when: format!("end of phase {:?}", mir_phase) } |
| .run_pass(tcx, source, body); |
| } |
| } |
| |
| fn mir_const_qualif(tcx: TyCtxt<'_>, def_id: DefId) -> ConstQualifs { |
| let def_id = def_id.expect_local(); |
| let const_kind = tcx.hir().body_const_context(def_id); |
| |
| // No need to const-check a non-const `fn`. |
| if const_kind.is_none() { |
| return Default::default(); |
| } |
| |
| // N.B., this `borrow()` is guaranteed to be valid (i.e., the value |
| // cannot yet be stolen), because `mir_validated()`, which steals |
| // from `mir_const(), forces this query to execute before |
| // performing the steal. |
| let body = &tcx.mir_const(def_id.to_def_id()).borrow(); |
| |
| if body.return_ty().references_error() { |
| tcx.sess.delay_span_bug(body.span, "mir_const_qualif: MIR had errors"); |
| return Default::default(); |
| } |
| |
| let ccx = |
| check_consts::ConstCx { body, tcx, def_id, const_kind, param_env: tcx.param_env(def_id) }; |
| |
| let mut validator = check_consts::validation::Validator::new(&ccx); |
| validator.check_body(); |
| |
| // We return the qualifs in the return place for every MIR body, even though it is only used |
| // when deciding to promote a reference to a `const` for now. |
| validator.qualifs_in_return_place() |
| } |
| |
| /// Make MIR ready for const evaluation. This is run on all MIR, not just on consts! |
| fn mir_const(tcx: TyCtxt<'_>, def_id: DefId) -> Steal<Body<'_>> { |
| let def_id = def_id.expect_local(); |
| |
| // Unsafety check uses the raw mir, so make sure it is run. |
| let _ = tcx.unsafety_check_result(def_id); |
| |
| let mut body = tcx.mir_built(def_id).steal(); |
| |
| util::dump_mir(tcx, None, "mir_map", &0, MirSource::item(def_id.to_def_id()), &body, |_, _| { |
| Ok(()) |
| }); |
| |
| run_passes( |
| tcx, |
| &mut body, |
| InstanceDef::Item(def_id.to_def_id()), |
| None, |
| MirPhase::Const, |
| &[&[ |
| // MIR-level lints. |
| &check_packed_ref::CheckPackedRef, |
| // What we need to do constant evaluation. |
| &simplify::SimplifyCfg::new("initial"), |
| &rustc_peek::SanityCheck, |
| ]], |
| ); |
| tcx.alloc_steal_mir(body) |
| } |
| |
| fn mir_validated( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| ) -> (Steal<Body<'tcx>>, Steal<IndexVec<Promoted, Body<'tcx>>>) { |
| // Ensure that we compute the `mir_const_qualif` for constants at |
| // this point, before we steal the mir-const result. |
| let _ = tcx.mir_const_qualif(def_id.to_def_id()); |
| |
| let mut body = tcx.mir_const(def_id.to_def_id()).steal(); |
| |
| let mut required_consts = Vec::new(); |
| let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts); |
| for (bb, bb_data) in traversal::reverse_postorder(&body) { |
| required_consts_visitor.visit_basic_block_data(bb, bb_data); |
| } |
| body.required_consts = required_consts; |
| |
| let promote_pass = promote_consts::PromoteTemps::default(); |
| run_passes( |
| tcx, |
| &mut body, |
| InstanceDef::Item(def_id.to_def_id()), |
| None, |
| MirPhase::Validated, |
| &[&[ |
| // What we need to run borrowck etc. |
| &promote_pass, |
| &simplify::SimplifyCfg::new("qualify-consts"), |
| // If the `instrument-coverage` option is enabled, analyze the CFG, identify each |
| // conditional branch, construct a coverage map to be passed to LLVM, and inject counters |
| // where needed. |
| &instrument_coverage::InstrumentCoverage, |
| ]], |
| ); |
| |
| let promoted = promote_pass.promoted_fragments.into_inner(); |
| (tcx.alloc_steal_mir(body), tcx.alloc_steal_promoted(promoted)) |
| } |
| |
| fn mir_drops_elaborated_and_const_checked<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| def_id: LocalDefId, |
| ) -> Steal<Body<'tcx>> { |
| // (Mir-)Borrowck uses `mir_validated`, so we have to force it to |
| // execute before we can steal. |
| tcx.ensure().mir_borrowck(def_id); |
| |
| let (body, _) = tcx.mir_validated(def_id); |
| let mut body = body.steal(); |
| |
| run_post_borrowck_cleanup_passes(tcx, &mut body, def_id, None); |
| check_consts::post_drop_elaboration::check_live_drops(tcx, def_id, &body); |
| tcx.alloc_steal_mir(body) |
| } |
| |
| /// After this series of passes, no lifetime analysis based on borrowing can be done. |
| fn run_post_borrowck_cleanup_passes<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| body: &mut Body<'tcx>, |
| def_id: LocalDefId, |
| promoted: Option<Promoted>, |
| ) { |
| debug!("post_borrowck_cleanup({:?})", def_id); |
| |
| let post_borrowck_cleanup: &[&dyn MirPass<'tcx>] = &[ |
| // Remove all things only needed by analysis |
| &no_landing_pads::NoLandingPads::new(tcx), |
| &simplify_branches::SimplifyBranches::new("initial"), |
| &remove_noop_landing_pads::RemoveNoopLandingPads, |
| &cleanup_post_borrowck::CleanupNonCodegenStatements, |
| &simplify::SimplifyCfg::new("early-opt"), |
| // These next passes must be executed together |
| &add_call_guards::CriticalCallEdges, |
| &elaborate_drops::ElaborateDrops, |
| &no_landing_pads::NoLandingPads::new(tcx), |
| // AddMovesForPackedDrops needs to run after drop |
| // elaboration. |
| &add_moves_for_packed_drops::AddMovesForPackedDrops, |
| // `AddRetag` needs to run after `ElaborateDrops`. Otherwise it should run fairly late, |
| // but before optimizations begin. |
| &add_retag::AddRetag, |
| &simplify::SimplifyCfg::new("elaborate-drops"), |
| ]; |
| |
| run_passes( |
| tcx, |
| body, |
| InstanceDef::Item(def_id.to_def_id()), |
| promoted, |
| MirPhase::DropElab, |
| &[post_borrowck_cleanup], |
| ); |
| } |
| |
| fn run_optimization_passes<'tcx>( |
| tcx: TyCtxt<'tcx>, |
| body: &mut Body<'tcx>, |
| def_id: LocalDefId, |
| promoted: Option<Promoted>, |
| ) { |
| let optimizations: &[&dyn MirPass<'tcx>] = &[ |
| &unreachable_prop::UnreachablePropagation, |
| &uninhabited_enum_branching::UninhabitedEnumBranching, |
| &simplify::SimplifyCfg::new("after-uninhabited-enum-branching"), |
| &inline::Inline, |
| // Lowering generator control-flow and variables has to happen before we do anything else |
| // to them. We do this inside the "optimizations" block so that it can benefit from |
| // optimizations that run before, that might be harder to do on the state machine than MIR |
| // with async primitives. |
| &generator::StateTransform, |
| &instcombine::InstCombine, |
| &const_prop::ConstProp, |
| &simplify_branches::SimplifyBranches::new("after-const-prop"), |
| // Run deaggregation here because: |
| // 1. Some codegen backends require it |
| // 2. It creates additional possibilities for some MIR optimizations to trigger |
| // FIXME(#70073): Why is this done here and not in `post_borrowck_cleanup`? |
| &deaggregator::Deaggregator, |
| &simplify_try::SimplifyArmIdentity, |
| &simplify_try::SimplifyBranchSame, |
| ©_prop::CopyPropagation, |
| &simplify_branches::SimplifyBranches::new("after-copy-prop"), |
| &remove_noop_landing_pads::RemoveNoopLandingPads, |
| &simplify::SimplifyCfg::new("after-remove-noop-landing-pads"), |
| &simplify::SimplifyCfg::new("final"), |
| &nrvo::RenameReturnPlace, |
| &simplify::SimplifyLocals, |
| ]; |
| |
| let no_optimizations: &[&dyn MirPass<'tcx>] = &[ |
| // Even if we don't do optimizations, we still have to lower generators for codegen. |
| &generator::StateTransform, |
| // FIXME(#70073): This pass is responsible for both optimization as well as some lints. |
| &const_prop::ConstProp, |
| // Even if we don't do optimizations, still run deaggregation because some backends assume |
| // that deaggregation always occurs. |
| &deaggregator::Deaggregator, |
| ]; |
| |
| let pre_codegen_cleanup: &[&dyn MirPass<'tcx>] = &[ |
| &add_call_guards::CriticalCallEdges, |
| // Dump the end result for testing and debugging purposes. |
| &dump_mir::Marker("PreCodegen"), |
| ]; |
| |
| let mir_opt_level = tcx.sess.opts.debugging_opts.mir_opt_level; |
| |
| #[rustfmt::skip] |
| run_passes( |
| tcx, |
| body, |
| InstanceDef::Item(def_id.to_def_id()), |
| promoted, |
| MirPhase::Optimized, |
| &[ |
| if mir_opt_level > 0 { optimizations } else { no_optimizations }, |
| pre_codegen_cleanup, |
| ], |
| ); |
| } |
| |
| fn optimized_mir(tcx: TyCtxt<'_>, def_id: DefId) -> Body<'_> { |
| if tcx.is_constructor(def_id) { |
| // There's no reason to run all of the MIR passes on constructors when |
| // we can just output the MIR we want directly. This also saves const |
| // qualification and borrow checking the trouble of special casing |
| // constructors. |
| return shim::build_adt_ctor(tcx, def_id); |
| } |
| |
| let def_id = def_id.expect_local(); |
| |
| let mut body = tcx.mir_drops_elaborated_and_const_checked(def_id).steal(); |
| run_optimization_passes(tcx, &mut body, def_id, None); |
| |
| debug_assert!(!body.has_free_regions(), "Free regions in optimized MIR"); |
| |
| body |
| } |
| |
| fn promoted_mir(tcx: TyCtxt<'_>, def_id: DefId) -> IndexVec<Promoted, Body<'_>> { |
| if tcx.is_constructor(def_id) { |
| return IndexVec::new(); |
| } |
| |
| let def_id = def_id.expect_local(); |
| |
| tcx.ensure().mir_borrowck(def_id); |
| let (_, promoted) = tcx.mir_validated(def_id); |
| let mut promoted = promoted.steal(); |
| |
| for (p, mut body) in promoted.iter_enumerated_mut() { |
| run_post_borrowck_cleanup_passes(tcx, &mut body, def_id, Some(p)); |
| run_optimization_passes(tcx, &mut body, def_id, Some(p)); |
| } |
| |
| debug_assert!(!promoted.has_free_regions(), "Free regions in promoted MIR"); |
| |
| promoted |
| } |
