c678acd3a2
Previously, when borrowck failed it would taint all promoteds within the MIR body. An attempt to evaluated the promoteds would subsequently fail with spurious "note: erroneous constant used". For example: ```console ... note: erroneous constant used --> tests/ui/borrowck/tainted-promoteds.rs:7:9 | 7 | a = &0 * &1 * &2 * &3; | ^^ note: erroneous constant used --> tests/ui/borrowck/tainted-promoteds.rs:7:14 | 7 | a = &0 * &1 * &2 * &3; | ^^ note: erroneous constant used --> tests/ui/borrowck/tainted-promoteds.rs:7:19 | 7 | a = &0 * &1 * &2 * &3; | ^^ note: erroneous constant used --> tests/ui/borrowck/tainted-promoteds.rs:7:24 | 7 | a = &0 * &1 * &2 * &3; | ^^ ``` Borrowck failure doesn't indicate that there is anything wrong with promoteds. Leave them untainted.
627 lines
25 KiB
Rust
627 lines
25 KiB
Rust
#![allow(rustc::potential_query_instability)]
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#![feature(box_patterns)]
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#![feature(drain_filter)]
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#![feature(let_chains)]
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#![feature(map_try_insert)]
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#![feature(min_specialization)]
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#![feature(never_type)]
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#![feature(option_get_or_insert_default)]
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#![feature(trusted_step)]
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#![feature(try_blocks)]
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#![feature(yeet_expr)]
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#![feature(if_let_guard)]
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#![recursion_limit = "256"]
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#[macro_use]
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extern crate tracing;
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#[macro_use]
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extern crate rustc_middle;
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use required_consts::RequiredConstsVisitor;
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use rustc_const_eval::util;
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use rustc_data_structures::fx::FxIndexSet;
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use rustc_data_structures::steal::Steal;
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use rustc_hir as hir;
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use rustc_hir::def::DefKind;
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use rustc_hir::def_id::LocalDefId;
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use rustc_hir::intravisit::{self, Visitor};
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use rustc_index::IndexVec;
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use rustc_middle::mir::visit::Visitor as _;
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use rustc_middle::mir::{
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traversal, AnalysisPhase, Body, ClearCrossCrate, ConstQualifs, Constant, LocalDecl, MirPass,
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MirPhase, Operand, Place, ProjectionElem, Promoted, RuntimePhase, Rvalue, SourceInfo,
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Statement, StatementKind, TerminatorKind, START_BLOCK,
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};
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use rustc_middle::ty::query::Providers;
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use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
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use rustc_span::sym;
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use rustc_trait_selection::traits;
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#[macro_use]
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mod pass_manager;
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use pass_manager::{self as pm, Lint, MirLint, WithMinOptLevel};
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mod abort_unwinding_calls;
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mod add_call_guards;
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mod add_moves_for_packed_drops;
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mod add_retag;
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mod check_const_item_mutation;
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mod check_packed_ref;
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pub mod check_unsafety;
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mod remove_place_mention;
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// This pass is public to allow external drivers to perform MIR cleanup
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pub mod cleanup_post_borrowck;
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mod const_debuginfo;
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mod const_goto;
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mod const_prop;
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mod const_prop_lint;
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mod copy_prop;
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mod coverage;
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mod ctfe_limit;
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mod dataflow_const_prop;
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mod dead_store_elimination;
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mod deduce_param_attrs;
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mod deduplicate_blocks;
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mod deref_separator;
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mod dest_prop;
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pub mod dump_mir;
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mod early_otherwise_branch;
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mod elaborate_box_derefs;
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mod elaborate_drops;
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mod ffi_unwind_calls;
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mod function_item_references;
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mod generator;
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mod inline;
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mod instcombine;
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mod large_enums;
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mod lower_intrinsics;
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mod lower_slice_len;
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mod match_branches;
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mod multiple_return_terminators;
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mod normalize_array_len;
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mod nrvo;
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mod remove_noop_landing_pads;
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mod remove_storage_markers;
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mod remove_uninit_drops;
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mod remove_unneeded_drops;
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mod remove_zsts;
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mod required_consts;
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mod reveal_all;
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mod separate_const_switch;
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mod shim;
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mod ssa;
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// This pass is public to allow external drivers to perform MIR cleanup
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mod check_alignment;
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pub mod simplify;
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mod simplify_branches;
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mod simplify_comparison_integral;
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mod sroa;
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mod uninhabited_enum_branching;
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mod unreachable_prop;
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use rustc_const_eval::transform::check_consts::{self, ConstCx};
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use rustc_const_eval::transform::promote_consts;
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use rustc_const_eval::transform::validate;
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use rustc_mir_dataflow::rustc_peek;
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pub fn provide(providers: &mut Providers) {
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check_unsafety::provide(providers);
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coverage::query::provide(providers);
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ffi_unwind_calls::provide(providers);
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shim::provide(providers);
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*providers = Providers {
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mir_keys,
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mir_const,
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mir_const_qualif,
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mir_promoted,
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mir_drops_elaborated_and_const_checked,
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mir_for_ctfe,
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mir_generator_witnesses: generator::mir_generator_witnesses,
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optimized_mir,
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is_mir_available,
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is_ctfe_mir_available: |tcx, did| is_mir_available(tcx, did),
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mir_callgraph_reachable: inline::cycle::mir_callgraph_reachable,
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mir_inliner_callees: inline::cycle::mir_inliner_callees,
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promoted_mir,
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deduced_param_attrs: deduce_param_attrs::deduced_param_attrs,
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..*providers
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};
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}
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fn remap_mir_for_const_eval_select<'tcx>(
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tcx: TyCtxt<'tcx>,
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mut body: Body<'tcx>,
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context: hir::Constness,
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) -> Body<'tcx> {
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for bb in body.basic_blocks.as_mut().iter_mut() {
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let terminator = bb.terminator.as_mut().expect("invalid terminator");
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match terminator.kind {
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TerminatorKind::Call {
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func: Operand::Constant(box Constant { ref literal, .. }),
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ref mut args,
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destination,
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target,
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unwind,
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fn_span,
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..
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} if let ty::FnDef(def_id, _) = *literal.ty().kind()
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&& tcx.item_name(def_id) == sym::const_eval_select
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&& tcx.is_intrinsic(def_id) =>
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{
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let [tupled_args, called_in_const, called_at_rt]: [_; 3] = std::mem::take(args).try_into().unwrap();
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let ty = tupled_args.ty(&body.local_decls, tcx);
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let fields = ty.tuple_fields();
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let num_args = fields.len();
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let func = if context == hir::Constness::Const { called_in_const } else { called_at_rt };
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let (method, place): (fn(Place<'tcx>) -> Operand<'tcx>, Place<'tcx>) = match tupled_args {
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Operand::Constant(_) => {
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// there is no good way of extracting a tuple arg from a constant (const generic stuff)
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// so we just create a temporary and deconstruct that.
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let local = body.local_decls.push(LocalDecl::new(ty, fn_span));
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bb.statements.push(Statement {
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source_info: SourceInfo::outermost(fn_span),
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kind: StatementKind::Assign(Box::new((local.into(), Rvalue::Use(tupled_args.clone())))),
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});
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(Operand::Move, local.into())
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}
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Operand::Move(place) => (Operand::Move, place),
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Operand::Copy(place) => (Operand::Copy, place),
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};
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let place_elems = place.projection;
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let arguments = (0..num_args).map(|x| {
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let mut place_elems = place_elems.to_vec();
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place_elems.push(ProjectionElem::Field(x.into(), fields[x]));
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let projection = tcx.mk_place_elems(&place_elems);
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let place = Place {
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local: place.local,
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projection,
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};
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method(place)
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}).collect();
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terminator.kind = TerminatorKind::Call { func, args: arguments, destination, target, unwind, from_hir_call: false, fn_span };
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}
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_ => {}
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}
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}
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body
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}
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fn is_mir_available(tcx: TyCtxt<'_>, def_id: LocalDefId) -> bool {
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tcx.mir_keys(()).contains(&def_id)
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}
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/// Finds the full set of `DefId`s within the current crate that have
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/// MIR associated with them.
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fn mir_keys(tcx: TyCtxt<'_>, (): ()) -> FxIndexSet<LocalDefId> {
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let mut set = FxIndexSet::default();
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// All body-owners have MIR associated with them.
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set.extend(tcx.hir().body_owners());
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// Additionally, tuple struct/variant constructors have MIR, but
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// they don't have a BodyId, so we need to build them separately.
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struct GatherCtors<'a> {
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set: &'a mut FxIndexSet<LocalDefId>,
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}
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impl<'tcx> Visitor<'tcx> for GatherCtors<'_> {
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fn visit_variant_data(&mut self, v: &'tcx hir::VariantData<'tcx>) {
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if let hir::VariantData::Tuple(_, _, def_id) = *v {
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self.set.insert(def_id);
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}
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intravisit::walk_struct_def(self, v)
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}
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}
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tcx.hir().visit_all_item_likes_in_crate(&mut GatherCtors { set: &mut set });
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set
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}
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fn mir_const_qualif(tcx: TyCtxt<'_>, def: LocalDefId) -> ConstQualifs {
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let const_kind = tcx.hir().body_const_context(def);
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// No need to const-check a non-const `fn`.
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if const_kind.is_none() {
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return Default::default();
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}
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// N.B., this `borrow()` is guaranteed to be valid (i.e., the value
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// cannot yet be stolen), because `mir_promoted()`, which steals
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// from `mir_const()`, forces this query to execute before
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// performing the steal.
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let body = &tcx.mir_const(def).borrow();
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if body.return_ty().references_error() {
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tcx.sess.delay_span_bug(body.span, "mir_const_qualif: MIR had errors");
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return Default::default();
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}
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let ccx = check_consts::ConstCx { body, tcx, const_kind, param_env: tcx.param_env(def) };
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let mut validator = check_consts::check::Checker::new(&ccx);
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validator.check_body();
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// We return the qualifs in the return place for every MIR body, even though it is only used
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// when deciding to promote a reference to a `const` for now.
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validator.qualifs_in_return_place()
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}
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/// Make MIR ready for const evaluation. This is run on all MIR, not just on consts!
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/// FIXME(oli-obk): it's unclear whether we still need this phase (and its corresponding query).
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/// We used to have this for pre-miri MIR based const eval.
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fn mir_const(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> {
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// Unsafety check uses the raw mir, so make sure it is run.
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if !tcx.sess.opts.unstable_opts.thir_unsafeck {
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tcx.ensure_with_value().unsafety_check_result(def);
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}
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// has_ffi_unwind_calls query uses the raw mir, so make sure it is run.
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tcx.ensure_with_value().has_ffi_unwind_calls(def);
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let mut body = tcx.mir_built(def).steal();
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pass_manager::dump_mir_for_phase_change(tcx, &body);
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pm::run_passes(
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tcx,
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&mut body,
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&[
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// MIR-level lints.
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&Lint(check_packed_ref::CheckPackedRef),
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&Lint(check_const_item_mutation::CheckConstItemMutation),
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&Lint(function_item_references::FunctionItemReferences),
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// What we need to do constant evaluation.
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&simplify::SimplifyCfg::Initial,
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&rustc_peek::SanityCheck, // Just a lint
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],
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None,
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);
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tcx.alloc_steal_mir(body)
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}
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/// Compute the main MIR body and the list of MIR bodies of the promoteds.
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fn mir_promoted(
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tcx: TyCtxt<'_>,
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def: LocalDefId,
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) -> (&Steal<Body<'_>>, &Steal<IndexVec<Promoted, Body<'_>>>) {
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// Ensure that we compute the `mir_const_qualif` for constants at
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// this point, before we steal the mir-const result.
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// Also this means promotion can rely on all const checks having been done.
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let const_qualifs = tcx.mir_const_qualif(def);
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let mut body = tcx.mir_const(def).steal();
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if let Some(error_reported) = const_qualifs.tainted_by_errors {
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body.tainted_by_errors = Some(error_reported);
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}
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let mut required_consts = Vec::new();
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let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
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for (bb, bb_data) in traversal::reverse_postorder(&body) {
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required_consts_visitor.visit_basic_block_data(bb, bb_data);
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}
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body.required_consts = required_consts;
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// What we need to run borrowck etc.
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let promote_pass = promote_consts::PromoteTemps::default();
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pm::run_passes(
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tcx,
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&mut body,
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&[&promote_pass, &simplify::SimplifyCfg::PromoteConsts, &coverage::InstrumentCoverage],
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Some(MirPhase::Analysis(AnalysisPhase::Initial)),
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);
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let promoted = promote_pass.promoted_fragments.into_inner();
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(tcx.alloc_steal_mir(body), tcx.alloc_steal_promoted(promoted))
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}
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/// Compute the MIR that is used during CTFE (and thus has no optimizations run on it)
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fn mir_for_ctfe(tcx: TyCtxt<'_>, def_id: LocalDefId) -> &Body<'_> {
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tcx.arena.alloc(inner_mir_for_ctfe(tcx, def_id))
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}
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fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
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// FIXME: don't duplicate this between the optimized_mir/mir_for_ctfe queries
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if tcx.is_constructor(def.to_def_id()) {
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// There's no reason to run all of the MIR passes on constructors when
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// we can just output the MIR we want directly. This also saves const
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// qualification and borrow checking the trouble of special casing
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// constructors.
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return shim::build_adt_ctor(tcx, def.to_def_id());
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}
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let context = tcx
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.hir()
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.body_const_context(def)
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.expect("mir_for_ctfe should not be used for runtime functions");
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let body = tcx.mir_drops_elaborated_and_const_checked(def).borrow().clone();
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let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::Const);
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match context {
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// Do not const prop functions, either they get executed at runtime or exported to metadata,
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// so we run const prop on them, or they don't, in which case we const evaluate some control
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// flow paths of the function and any errors in those paths will get emitted as const eval
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// errors.
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hir::ConstContext::ConstFn => {}
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// Static items always get evaluated, so we can just let const eval see if any erroneous
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// control flow paths get executed.
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hir::ConstContext::Static(_) => {}
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// Associated constants get const prop run so we detect common failure situations in the
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// crate that defined the constant.
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// Technically we want to not run on regular const items, but oli-obk doesn't know how to
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// conveniently detect that at this point without looking at the HIR.
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hir::ConstContext::Const => {
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pm::run_passes(
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tcx,
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&mut body,
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&[&const_prop::ConstProp],
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Some(MirPhase::Runtime(RuntimePhase::Optimized)),
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);
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}
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}
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pm::run_passes(tcx, &mut body, &[&ctfe_limit::CtfeLimit], None);
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body
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}
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/// Obtain just the main MIR (no promoteds) and run some cleanups on it. This also runs
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/// mir borrowck *before* doing so in order to ensure that borrowck can be run and doesn't
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/// end up missing the source MIR due to stealing happening.
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fn mir_drops_elaborated_and_const_checked(tcx: TyCtxt<'_>, def: LocalDefId) -> &Steal<Body<'_>> {
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if tcx.sess.opts.unstable_opts.drop_tracking_mir
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&& let DefKind::Generator = tcx.def_kind(def)
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{
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tcx.ensure_with_value().mir_generator_witnesses(def);
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}
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let mir_borrowck = tcx.mir_borrowck(def);
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let is_fn_like = tcx.def_kind(def).is_fn_like();
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if is_fn_like {
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// Do not compute the mir call graph without said call graph actually being used.
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|
if inline::Inline.is_enabled(&tcx.sess) {
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tcx.ensure_with_value().mir_inliner_callees(ty::InstanceDef::Item(def.to_def_id()));
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}
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}
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let (body, _) = tcx.mir_promoted(def);
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|
let mut body = body.steal();
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|
if let Some(error_reported) = mir_borrowck.tainted_by_errors {
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body.tainted_by_errors = Some(error_reported);
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}
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// Check if it's even possible to satisfy the 'where' clauses
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// for this item.
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//
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// This branch will never be taken for any normal function.
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|
// However, it's possible to `#!feature(trivial_bounds)]` to write
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|
// a function with impossible to satisfy clauses, e.g.:
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// `fn foo() where String: Copy {}`
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|
//
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|
// We don't usually need to worry about this kind of case,
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|
// since we would get a compilation error if the user tried
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// to call it. However, since we optimize even without any
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// calls to the function, we need to make sure that it even
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// makes sense to try to evaluate the body.
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//
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|
// If there are unsatisfiable where clauses, then all bets are
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// off, and we just give up.
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|
//
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|
// We manually filter the predicates, skipping anything that's not
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|
// "global". We are in a potentially generic context
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|
// (e.g. we are evaluating a function without substituting generic
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|
// parameters, so this filtering serves two purposes:
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|
//
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|
// 1. We skip evaluating any predicates that we would
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|
// never be able prove are unsatisfiable (e.g. `<T as Foo>`
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|
// 2. We avoid trying to normalize predicates involving generic
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// parameters (e.g. `<T as Foo>::MyItem`). This can confuse
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// the normalization code (leading to cycle errors), since
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// it's usually never invoked in this way.
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let predicates = tcx
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.predicates_of(body.source.def_id())
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.predicates
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.iter()
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.filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
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|
if traits::impossible_predicates(tcx, traits::elaborate(tcx, predicates).collect()) {
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trace!("found unsatisfiable predicates for {:?}", body.source);
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// Clear the body to only contain a single `unreachable` statement.
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|
let bbs = body.basic_blocks.as_mut();
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|
bbs.raw.truncate(1);
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bbs[START_BLOCK].statements.clear();
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bbs[START_BLOCK].terminator_mut().kind = TerminatorKind::Unreachable;
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body.var_debug_info.clear();
|
|
body.local_decls.raw.truncate(body.arg_count + 1);
|
|
}
|
|
|
|
run_analysis_to_runtime_passes(tcx, &mut body);
|
|
|
|
tcx.alloc_steal_mir(body)
|
|
}
|
|
|
|
fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
|
|
assert!(body.phase == MirPhase::Analysis(AnalysisPhase::Initial));
|
|
let did = body.source.def_id();
|
|
|
|
debug!("analysis_mir_cleanup({:?})", did);
|
|
run_analysis_cleanup_passes(tcx, body);
|
|
assert!(body.phase == MirPhase::Analysis(AnalysisPhase::PostCleanup));
|
|
|
|
// Do a little drop elaboration before const-checking if `const_precise_live_drops` is enabled.
|
|
if check_consts::post_drop_elaboration::checking_enabled(&ConstCx::new(tcx, &body)) {
|
|
pm::run_passes(
|
|
tcx,
|
|
body,
|
|
&[&remove_uninit_drops::RemoveUninitDrops, &simplify::SimplifyCfg::RemoveFalseEdges],
|
|
None,
|
|
);
|
|
check_consts::post_drop_elaboration::check_live_drops(tcx, &body); // FIXME: make this a MIR lint
|
|
}
|
|
|
|
debug!("runtime_mir_lowering({:?})", did);
|
|
run_runtime_lowering_passes(tcx, body);
|
|
assert!(body.phase == MirPhase::Runtime(RuntimePhase::Initial));
|
|
|
|
debug!("runtime_mir_cleanup({:?})", did);
|
|
run_runtime_cleanup_passes(tcx, body);
|
|
assert!(body.phase == MirPhase::Runtime(RuntimePhase::PostCleanup));
|
|
}
|
|
|
|
// FIXME(JakobDegen): Can we make these lists of passes consts?
|
|
|
|
/// After this series of passes, no lifetime analysis based on borrowing can be done.
|
|
fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
|
|
let passes: &[&dyn MirPass<'tcx>] = &[
|
|
&cleanup_post_borrowck::CleanupPostBorrowck,
|
|
&remove_noop_landing_pads::RemoveNoopLandingPads,
|
|
&simplify::SimplifyCfg::EarlyOpt,
|
|
&deref_separator::Derefer,
|
|
];
|
|
|
|
pm::run_passes(tcx, body, passes, Some(MirPhase::Analysis(AnalysisPhase::PostCleanup)));
|
|
}
|
|
|
|
/// Returns the sequence of passes that lowers analysis to runtime MIR.
|
|
fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
|
|
let passes: &[&dyn MirPass<'tcx>] = &[
|
|
// These next passes must be executed together
|
|
&add_call_guards::CriticalCallEdges,
|
|
&elaborate_drops::ElaborateDrops,
|
|
// This will remove extraneous landing pads which are no longer
|
|
// necessary as well as well as forcing any call in a non-unwinding
|
|
// function calling a possibly-unwinding function to abort the process.
|
|
&abort_unwinding_calls::AbortUnwindingCalls,
|
|
// 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.
|
|
&elaborate_box_derefs::ElaborateBoxDerefs,
|
|
&generator::StateTransform,
|
|
&add_retag::AddRetag,
|
|
&Lint(const_prop_lint::ConstProp),
|
|
];
|
|
pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
|
|
}
|
|
|
|
/// Returns the sequence of passes that do the initial cleanup of runtime MIR.
|
|
fn run_runtime_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
|
|
let passes: &[&dyn MirPass<'tcx>] = &[
|
|
&lower_intrinsics::LowerIntrinsics,
|
|
&remove_place_mention::RemovePlaceMention,
|
|
&simplify::SimplifyCfg::ElaborateDrops,
|
|
];
|
|
|
|
pm::run_passes(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::PostCleanup)));
|
|
|
|
// Clear this by anticipation. Optimizations and runtime MIR have no reason to look
|
|
// into this information, which is meant for borrowck diagnostics.
|
|
for decl in &mut body.local_decls {
|
|
decl.local_info = ClearCrossCrate::Clear;
|
|
}
|
|
}
|
|
|
|
fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
|
|
fn o1<T>(x: T) -> WithMinOptLevel<T> {
|
|
WithMinOptLevel(1, x)
|
|
}
|
|
|
|
// The main optimizations that we do on MIR.
|
|
pm::run_passes(
|
|
tcx,
|
|
body,
|
|
&[
|
|
&check_alignment::CheckAlignment,
|
|
&reveal_all::RevealAll, // has to be done before inlining, since inlined code is in RevealAll mode.
|
|
&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
|
|
&unreachable_prop::UnreachablePropagation,
|
|
&uninhabited_enum_branching::UninhabitedEnumBranching,
|
|
&o1(simplify::SimplifyCfg::AfterUninhabitedEnumBranching),
|
|
&inline::Inline,
|
|
&remove_storage_markers::RemoveStorageMarkers,
|
|
&remove_zsts::RemoveZsts,
|
|
&normalize_array_len::NormalizeArrayLen, // has to run after `slice::len` lowering
|
|
&const_goto::ConstGoto,
|
|
&remove_unneeded_drops::RemoveUnneededDrops,
|
|
&sroa::ScalarReplacementOfAggregates,
|
|
&match_branches::MatchBranchSimplification,
|
|
// inst combine is after MatchBranchSimplification to clean up Ne(_1, false)
|
|
&multiple_return_terminators::MultipleReturnTerminators,
|
|
&instcombine::InstCombine,
|
|
&separate_const_switch::SeparateConstSwitch,
|
|
&simplify::SimplifyLocals::BeforeConstProp,
|
|
©_prop::CopyProp,
|
|
&const_prop::ConstProp,
|
|
&dataflow_const_prop::DataflowConstProp,
|
|
//
|
|
// Const-prop runs unconditionally, but doesn't mutate the MIR at mir-opt-level=0.
|
|
&const_debuginfo::ConstDebugInfo,
|
|
&o1(simplify_branches::SimplifyConstCondition::AfterConstProp),
|
|
&early_otherwise_branch::EarlyOtherwiseBranch,
|
|
&simplify_comparison_integral::SimplifyComparisonIntegral,
|
|
&dead_store_elimination::DeadStoreElimination,
|
|
&dest_prop::DestinationPropagation,
|
|
&o1(simplify_branches::SimplifyConstCondition::Final),
|
|
&o1(remove_noop_landing_pads::RemoveNoopLandingPads),
|
|
&o1(simplify::SimplifyCfg::Final),
|
|
&nrvo::RenameReturnPlace,
|
|
&simplify::SimplifyLocals::Final,
|
|
&multiple_return_terminators::MultipleReturnTerminators,
|
|
&deduplicate_blocks::DeduplicateBlocks,
|
|
&large_enums::EnumSizeOpt { discrepancy: 128 },
|
|
// Some cleanup necessary at least for LLVM and potentially other codegen backends.
|
|
&add_call_guards::CriticalCallEdges,
|
|
// Dump the end result for testing and debugging purposes.
|
|
&dump_mir::Marker("PreCodegen"),
|
|
],
|
|
Some(MirPhase::Runtime(RuntimePhase::Optimized)),
|
|
);
|
|
}
|
|
|
|
/// Optimize the MIR and prepare it for codegen.
|
|
fn optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> &Body<'_> {
|
|
tcx.arena.alloc(inner_optimized_mir(tcx, did))
|
|
}
|
|
|
|
fn inner_optimized_mir(tcx: TyCtxt<'_>, did: LocalDefId) -> Body<'_> {
|
|
if tcx.is_constructor(did.to_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, did.to_def_id());
|
|
}
|
|
|
|
match tcx.hir().body_const_context(did) {
|
|
// Run the `mir_for_ctfe` query, which depends on `mir_drops_elaborated_and_const_checked`
|
|
// which we are going to steal below. Thus we need to run `mir_for_ctfe` first, so it
|
|
// computes and caches its result.
|
|
Some(hir::ConstContext::ConstFn) => tcx.ensure_with_value().mir_for_ctfe(did),
|
|
None => {}
|
|
Some(other) => panic!("do not use `optimized_mir` for constants: {:?}", other),
|
|
}
|
|
debug!("about to call mir_drops_elaborated...");
|
|
let body = tcx.mir_drops_elaborated_and_const_checked(did).steal();
|
|
let mut body = remap_mir_for_const_eval_select(tcx, body, hir::Constness::NotConst);
|
|
debug!("body: {:#?}", body);
|
|
run_optimization_passes(tcx, &mut body);
|
|
|
|
body
|
|
}
|
|
|
|
/// Fetch all the promoteds of an item and prepare their MIR bodies to be ready for
|
|
/// constant evaluation once all substitutions become known.
|
|
fn promoted_mir(tcx: TyCtxt<'_>, def: LocalDefId) -> &IndexVec<Promoted, Body<'_>> {
|
|
if tcx.is_constructor(def.to_def_id()) {
|
|
return tcx.arena.alloc(IndexVec::new());
|
|
}
|
|
|
|
tcx.ensure_with_value().mir_borrowck(def);
|
|
let mut promoted = tcx.mir_promoted(def).1.steal();
|
|
|
|
for body in &mut promoted {
|
|
run_analysis_to_runtime_passes(tcx, body);
|
|
}
|
|
|
|
tcx.arena.alloc(promoted)
|
|
}
|