Auto merge of #67901 - matthewjasper:split-mir-build, r=nagisa

Split MIR building into its own crate

This moves `rustc_mir::{build, hair, lints}` to `rustc_mir_build`.
The new crate only has a `provide` function as it's public API.

Based on #67898

cc @Centril @rust-lang/compiler
r? @oli-obk

Author: bors

Cargo.lock

@@ -3633,6 +3633,7 @@ dependencies = [
  "rustc_lint",
  "rustc_metadata",
  "rustc_mir",
+ "rustc_mir_build",
  "rustc_parse",
  "rustc_passes",
  "rustc_plugin_impl",
@@ -3722,7 +3723,6 @@ dependencies = [
 name = "rustc_mir"
 version = "0.0.0"
 dependencies = [
- "arena",
  "either",
  "graphviz",
  "itertools 0.8.0",
@@ -3745,6 +3745,28 @@ dependencies = [
  "syntax",
 ]
 
+[[package]]
+name = "rustc_mir_build"
+version = "0.0.0"
+dependencies = [
+ "arena",
+ "itertools 0.8.0",
+ "log",
+ "rustc",
+ "rustc_apfloat",
+ "rustc_data_structures",
+ "rustc_error_codes",
+ "rustc_errors",
+ "rustc_hir",
+ "rustc_index",
+ "rustc_macros",
+ "rustc_span",
+ "rustc_target",
+ "serialize",
+ "smallvec 1.0.0",
+ "syntax",
+]
+
 [[package]]
 name = "rustc_parse"
 version = "0.0.0"

src/librustc/mir/mod.rs

@@ -1,5 +1,3 @@
-// ignore-tidy-filelength
-
 //! MIR datatypes and passes. See the [rustc guide] for more info.
 //!
 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
@@ -23,14 +21,12 @@ use polonius_engine::Atom;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::graph::dominators::Dominators;
 use rustc_data_structures::graph::{self, GraphSuccessors};
-use rustc_data_structures::sync::Lrc;
 use rustc_index::bit_set::BitMatrix;
 use rustc_index::vec::{Idx, IndexVec};
 use rustc_macros::HashStable;
 use rustc_serialize::{Decodable, Encodable};
 use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
-use smallvec::SmallVec;
 use std::borrow::Cow;
 use std::fmt::{self, Debug, Display, Formatter, Write};
 use std::ops::Index;
@@ -39,13 +35,15 @@ use std::{iter, mem, option, u32};
 pub use syntax::ast::Mutability;
 use syntax::ast::Name;
 
-pub use crate::mir::cache::{BodyAndCache, ReadOnlyBodyAndCache};
-pub use crate::mir::interpret::AssertMessage;
+pub use self::cache::{BodyAndCache, ReadOnlyBodyAndCache};
+pub use self::interpret::AssertMessage;
+pub use self::query::*;
 pub use crate::read_only;
 
 mod cache;
 pub mod interpret;
 pub mod mono;
+mod query;
 pub mod tcx;
 pub mod traversal;
 pub mod visit;
@@ -2581,221 +2579,6 @@ impl Location {
     }
 }
 
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
-pub enum UnsafetyViolationKind {
-    General,
-    /// Permitted both in `const fn`s and regular `fn`s.
-    GeneralAndConstFn,
-    BorrowPacked(hir::HirId),
-}
-
-#[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
-pub struct UnsafetyViolation {
-    pub source_info: SourceInfo,
-    pub description: Symbol,
-    pub details: Symbol,
-    pub kind: UnsafetyViolationKind,
-}
-
-#[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
-pub struct UnsafetyCheckResult {
-    /// Violations that are propagated *upwards* from this function.
-    pub violations: Lrc<[UnsafetyViolation]>,
-    /// `unsafe` blocks in this function, along with whether they are used. This is
-    /// used for the "unused_unsafe" lint.
-    pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
-}
-
-rustc_index::newtype_index! {
-    pub struct GeneratorSavedLocal {
-        derive [HashStable]
-        DEBUG_FORMAT = "_{}",
-    }
-}
-
-/// The layout of generator state.
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
-pub struct GeneratorLayout<'tcx> {
-    /// The type of every local stored inside the generator.
-    pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
-
-    /// Which of the above fields are in each variant. Note that one field may
-    /// be stored in multiple variants.
-    pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
-
-    /// Which saved locals are storage-live at the same time. Locals that do not
-    /// have conflicts with each other are allowed to overlap in the computed
-    /// layout.
-    pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
-}
-
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct BorrowCheckResult<'tcx> {
-    pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
-    pub used_mut_upvars: SmallVec<[Field; 8]>,
-}
-
-/// The result of the `mir_const_qualif` query.
-///
-/// Each field corresponds to an implementer of the `Qualif` trait in
-/// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
-/// `Qualif`.
-#[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
-pub struct ConstQualifs {
-    pub has_mut_interior: bool,
-    pub needs_drop: bool,
-}
-
-/// After we borrow check a closure, we are left with various
-/// requirements that we have inferred between the free regions that
-/// appear in the closure's signature or on its field types. These
-/// requirements are then verified and proved by the closure's
-/// creating function. This struct encodes those requirements.
-///
-/// The requirements are listed as being between various
-/// `RegionVid`. The 0th region refers to `'static`; subsequent region
-/// vids refer to the free regions that appear in the closure (or
-/// generator's) type, in order of appearance. (This numbering is
-/// actually defined by the `UniversalRegions` struct in the NLL
-/// region checker. See for example
-/// `UniversalRegions::closure_mapping`.) Note that we treat the free
-/// regions in the closure's type "as if" they were erased, so their
-/// precise identity is not important, only their position.
-///
-/// Example: If type check produces a closure with the closure substs:
-///
-/// ```text
-/// ClosureSubsts = [
-///     i8,                                  // the "closure kind"
-///     for<'x> fn(&'a &'x u32) -> &'x u32,  // the "closure signature"
-///     &'a String,                          // some upvar
-/// ]
-/// ```
-///
-/// here, there is one unique free region (`'a`) but it appears
-/// twice. We would "renumber" each occurrence to a unique vid, as follows:
-///
-/// ```text
-/// ClosureSubsts = [
-///     i8,                                  // the "closure kind"
-///     for<'x> fn(&'1 &'x u32) -> &'x u32,  // the "closure signature"
-///     &'2 String,                          // some upvar
-/// ]
-/// ```
-///
-/// Now the code might impose a requirement like `'1: '2`. When an
-/// instance of the closure is created, the corresponding free regions
-/// can be extracted from its type and constrained to have the given
-/// outlives relationship.
-///
-/// In some cases, we have to record outlives requirements between
-/// types and regions as well. In that case, if those types include
-/// any regions, those regions are recorded as `ReClosureBound`
-/// instances assigned one of these same indices. Those regions will
-/// be substituted away by the creator. We use `ReClosureBound` in
-/// that case because the regions must be allocated in the global
-/// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
-/// internally within the rest of the NLL code).
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct ClosureRegionRequirements<'tcx> {
-    /// The number of external regions defined on the closure. In our
-    /// example above, it would be 3 -- one for `'static`, then `'1`
-    /// and `'2`. This is just used for a sanity check later on, to
-    /// make sure that the number of regions we see at the callsite
-    /// matches.
-    pub num_external_vids: usize,
-
-    /// Requirements between the various free regions defined in
-    /// indices.
-    pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
-}
-
-/// Indicates an outlives-constraint between a type or between two
-/// free regions declared on the closure.
-#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub struct ClosureOutlivesRequirement<'tcx> {
-    // This region or type ...
-    pub subject: ClosureOutlivesSubject<'tcx>,
-
-    // ... must outlive this one.
-    pub outlived_free_region: ty::RegionVid,
-
-    // If not, report an error here ...
-    pub blame_span: Span,
-
-    // ... due to this reason.
-    pub category: ConstraintCategory,
-}
-
-/// Outlives-constraints can be categorized to determine whether and why they
-/// are interesting (for error reporting). Order of variants indicates sort
-/// order of the category, thereby influencing diagnostic output.
-///
-/// See also [rustc_mir::borrow_check::nll::constraints].
-#[derive(
-    Copy,
-    Clone,
-    Debug,
-    Eq,
-    PartialEq,
-    PartialOrd,
-    Ord,
-    Hash,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
-pub enum ConstraintCategory {
-    Return,
-    Yield,
-    UseAsConst,
-    UseAsStatic,
-    TypeAnnotation,
-    Cast,
-
-    /// A constraint that came from checking the body of a closure.
-    ///
-    /// We try to get the category that the closure used when reporting this.
-    ClosureBounds,
-    CallArgument,
-    CopyBound,
-    SizedBound,
-    Assignment,
-    OpaqueType,
-
-    /// A "boring" constraint (caused by the given location) is one that
-    /// the user probably doesn't want to see described in diagnostics,
-    /// because it is kind of an artifact of the type system setup.
-    /// Example: `x = Foo { field: y }` technically creates
-    /// intermediate regions representing the "type of `Foo { field: y
-    /// }`", and data flows from `y` into those variables, but they
-    /// are not very interesting. The assignment into `x` on the other
-    /// hand might be.
-    Boring,
-    // Boring and applicable everywhere.
-    BoringNoLocation,
-
-    /// A constraint that doesn't correspond to anything the user sees.
-    Internal,
-}
-
-/// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
-/// that must outlive some region.
-#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
-pub enum ClosureOutlivesSubject<'tcx> {
-    /// Subject is a type, typically a type parameter, but could also
-    /// be a projection. Indicates a requirement like `T: 'a` being
-    /// passed to the caller, where the type here is `T`.
-    ///
-    /// The type here is guaranteed not to contain any free regions at
-    /// present.
-    Ty(Ty<'tcx>),
-
-    /// Subject is a free region from the closure. Indicates a requirement
-    /// like `'a: 'b` being passed to the caller; the region here is `'a`.
-    Region(ty::RegionVid),
-}
-
 /*
  * `TypeFoldable` implementations for MIR types
 */