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#![deny(rustc::untranslatable_diagnostic)]
#![deny(rustc::diagnostic_outside_of_impl)]
//! This file provides API for compiler consumers.
use rustc_hir::def_id::LocalDefId;
use rustc_index::{IndexSlice, IndexVec};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir::{Body, Promoted};
use rustc_middle::traits::DefiningAnchor;
use rustc_middle::ty::TyCtxt;
use std::rc::Rc;
use crate::borrow_set::BorrowSet;
pub use super::{
constraints::OutlivesConstraint,
dataflow::{calculate_borrows_out_of_scope_at_location, BorrowIndex, Borrows},
facts::{AllFacts as PoloniusInput, RustcFacts},
location::{LocationTable, RichLocation},
nll::PoloniusOutput,
place_ext::PlaceExt,
places_conflict::{places_conflict, PlaceConflictBias},
region_infer::RegionInferenceContext,
};
/// Options determining the output behavior of [`get_body_with_borrowck_facts`].
///
/// If executing under `-Z polonius` the choice here has no effect, and everything as if
/// [`PoloniusOutputFacts`](ConsumerOptions::PoloniusOutputFacts) had been selected
/// will be retrieved.
#[derive(Debug, Copy, Clone)]
pub enum ConsumerOptions {
/// Retrieve the [`Body`] along with the [`BorrowSet`]
/// and [`RegionInferenceContext`]. If you would like the body only, use
/// [`TyCtxt::mir_promoted`].
///
/// These can be used in conjunction with [`calculate_borrows_out_of_scope_at_location`].
RegionInferenceContext,
/// The recommended option. Retrieves the maximal amount of information
/// without significant slowdowns.
///
/// Implies [`RegionInferenceContext`](ConsumerOptions::RegionInferenceContext),
/// and additionally retrieve the [`LocationTable`] and [`PoloniusInput`] that
/// would be given to Polonius. Critically, this does not run Polonius, which
/// one may want to avoid due to performance issues on large bodies.
PoloniusInputFacts,
/// Implies [`PoloniusInputFacts`](ConsumerOptions::PoloniusInputFacts),
/// and additionally runs Polonius to calculate the [`PoloniusOutput`].
PoloniusOutputFacts,
}
impl ConsumerOptions {
/// Should the Polonius input facts be computed?
pub(crate) fn polonius_input(&self) -> bool {
matches!(self, Self::PoloniusInputFacts | Self::PoloniusOutputFacts)
}
/// Should we run Polonius and collect the output facts?
pub(crate) fn polonius_output(&self) -> bool {
matches!(self, Self::PoloniusOutputFacts)
}
}
/// A `Body` with information computed by the borrow checker. This struct is
/// intended to be consumed by compiler consumers.
///
/// We need to include the MIR body here because the region identifiers must
/// match the ones in the Polonius facts.
pub struct BodyWithBorrowckFacts<'tcx> {
/// A mir body that contains region identifiers.
pub body: Body<'tcx>,
/// The mir bodies of promoteds.
pub promoted: IndexVec<Promoted, Body<'tcx>>,
/// The set of borrows occurring in `body` with data about them.
pub borrow_set: Rc<BorrowSet<'tcx>>,
/// Context generated during borrowck, intended to be passed to
/// [`calculate_borrows_out_of_scope_at_location`].
pub region_inference_context: Rc<RegionInferenceContext<'tcx>>,
/// The table that maps Polonius points to locations in the table.
/// Populated when using [`ConsumerOptions::PoloniusInputFacts`]
/// or [`ConsumerOptions::PoloniusOutputFacts`].
pub location_table: Option<LocationTable>,
/// Polonius input facts.
/// Populated when using [`ConsumerOptions::PoloniusInputFacts`]
/// or [`ConsumerOptions::PoloniusOutputFacts`].
pub input_facts: Option<Box<PoloniusInput>>,
/// Polonius output facts. Populated when using
/// [`ConsumerOptions::PoloniusOutputFacts`].
pub output_facts: Option<Rc<PoloniusOutput>>,
}
/// This function computes borrowck facts for the given body. The [`ConsumerOptions`]
/// determine which facts are returned. This function makes a copy of the body because
/// it needs to regenerate the region identifiers. It should never be invoked during a
/// typical compilation session due to the unnecessary overhead of returning
/// [`BodyWithBorrowckFacts`].
///
/// Note:
/// * This function will panic if the required body was already stolen. This
/// can, for example, happen when requesting a body of a `const` function
/// because they are evaluated during typechecking. The panic can be avoided
/// by overriding the `mir_borrowck` query. You can find a complete example
/// that shows how to do this at `tests/run-make/obtain-borrowck/`.
///
/// * Polonius is highly unstable, so expect regular changes in its signature or other details.
pub fn get_body_with_borrowck_facts(
tcx: TyCtxt<'_>,
def: LocalDefId,
options: ConsumerOptions,
) -> BodyWithBorrowckFacts<'_> {
let (input_body, promoted) = tcx.mir_promoted(def);
let infcx = tcx.infer_ctxt().with_opaque_type_inference(DefiningAnchor::Bind(def)).build();
let input_body: &Body<'_> = &input_body.borrow();
let promoted: &IndexSlice<_, _> = &promoted.borrow();
*super::do_mir_borrowck(&infcx, input_body, promoted, Some(options)).1.unwrap()
}
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