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3509 lines
134 KiB
Rust
3509 lines
134 KiB
Rust
//! MIR datatypes and passes. See the [rustc dev guide] for more info.
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//!
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//! [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/mir/index.html
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use crate::mir::coverage::{CodeRegion, CoverageKind};
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use crate::mir::interpret::{ConstAllocation, ConstValue, GlobalAlloc, Scalar};
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use crate::mir::visit::MirVisitable;
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use crate::ty::adjustment::PointerCast;
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use crate::ty::codec::{TyDecoder, TyEncoder};
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use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeVisitor};
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use crate::ty::print::{FmtPrinter, Printer};
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use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
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use crate::ty::{self, List, Ty, TyCtxt};
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use crate::ty::{AdtDef, InstanceDef, Region, ScalarInt, UserTypeAnnotationIndex};
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use rustc_errors::ErrorGuaranteed;
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use rustc_hir::def::{CtorKind, Namespace};
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use rustc_hir::def_id::{DefId, LocalDefId, CRATE_DEF_ID};
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use rustc_hir::{self, GeneratorKind};
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use rustc_hir::{self as hir, HirId};
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use rustc_session::Session;
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use rustc_target::abi::{Size, VariantIdx};
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use polonius_engine::Atom;
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pub use rustc_ast::Mutability;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_data_structures::graph::dominators::{dominators, Dominators};
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use rustc_data_structures::graph::{self, GraphSuccessors};
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use rustc_index::bit_set::BitMatrix;
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use rustc_index::vec::{Idx, IndexVec};
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use rustc_serialize::{Decodable, Encodable};
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use rustc_span::symbol::Symbol;
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use rustc_span::{Span, DUMMY_SP};
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use rustc_target::asm::InlineAsmRegOrRegClass;
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use either::Either;
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use std::borrow::Cow;
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use std::convert::TryInto;
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use std::fmt::{self, Debug, Display, Formatter, Write};
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use std::ops::{ControlFlow, Index, IndexMut};
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use std::slice;
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use std::{iter, mem, option};
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use self::graph_cyclic_cache::GraphIsCyclicCache;
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use self::predecessors::{PredecessorCache, Predecessors};
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pub use self::query::*;
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use self::switch_sources::{SwitchSourceCache, SwitchSources};
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pub mod coverage;
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mod generic_graph;
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pub mod generic_graphviz;
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mod graph_cyclic_cache;
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pub mod graphviz;
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pub mod interpret;
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pub mod mono;
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pub mod patch;
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mod predecessors;
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pub mod pretty;
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mod query;
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pub mod spanview;
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mod switch_sources;
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pub mod tcx;
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pub mod terminator;
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pub use terminator::*;
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pub mod traversal;
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mod type_foldable;
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pub mod visit;
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pub use self::generic_graph::graphviz_safe_def_name;
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pub use self::graphviz::write_mir_graphviz;
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pub use self::pretty::{
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create_dump_file, display_allocation, dump_enabled, dump_mir, write_mir_pretty, PassWhere,
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};
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/// Types for locals
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pub type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
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pub trait HasLocalDecls<'tcx> {
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fn local_decls(&self) -> &LocalDecls<'tcx>;
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}
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impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
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#[inline]
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fn local_decls(&self) -> &LocalDecls<'tcx> {
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self
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}
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}
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impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
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#[inline]
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fn local_decls(&self) -> &LocalDecls<'tcx> {
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&self.local_decls
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}
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}
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/// A streamlined trait that you can implement to create a pass; the
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/// pass will be named after the type, and it will consist of a main
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/// loop that goes over each available MIR and applies `run_pass`.
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pub trait MirPass<'tcx> {
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fn name(&self) -> Cow<'_, str> {
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let name = std::any::type_name::<Self>();
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if let Some(tail) = name.rfind(':') {
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Cow::from(&name[tail + 1..])
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} else {
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Cow::from(name)
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}
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}
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/// Returns `true` if this pass is enabled with the current combination of compiler flags.
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fn is_enabled(&self, _sess: &Session) -> bool {
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true
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}
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fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>);
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/// If this pass causes the MIR to enter a new phase, return that phase.
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fn phase_change(&self) -> Option<MirPhase> {
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None
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}
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fn is_mir_dump_enabled(&self) -> bool {
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true
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}
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}
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/// The various "big phases" that MIR goes through.
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///
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/// These phases all describe dialects of MIR. Since all MIR uses the same datastructures, the
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/// dialects forbid certain variants or values in certain phases. The sections below summarize the
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/// changes, but do not document them thoroughly. The full documentation is found in the appropriate
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/// documentation for the thing the change is affecting.
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///
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/// Warning: ordering of variants is significant.
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#[derive(Copy, Clone, TyEncodable, TyDecodable, Debug, PartialEq, Eq, PartialOrd, Ord)]
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#[derive(HashStable)]
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pub enum MirPhase {
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/// The dialect of MIR used during all phases before `DropsLowered` is the same. This is also
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/// the MIR that analysis such as borrowck uses.
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///
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/// One important thing to remember about the behavior of this section of MIR is that drop terminators
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/// (including drop and replace) are *conditional*. The elaborate drops pass will then replace each
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/// instance of a drop terminator with a nop, an unconditional drop, or a drop conditioned on a drop
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/// flag. Of course, this means that it is important that the drop elaboration can accurately recognize
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/// when things are initialized and when things are de-initialized. That means any code running on this
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/// version of MIR must be sure to produce output that drop elaboration can reason about. See the
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/// section on the drop terminatorss for more details.
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Built = 0,
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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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Const = 1,
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/// This phase checks the MIR for promotable elements and takes them out of the main MIR body
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/// by creating a new MIR body per promoted element. After this phase (and thus the termination
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/// of the `mir_promoted` query), these promoted elements are available in the `promoted_mir`
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/// query.
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ConstsPromoted = 2,
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/// Beginning with this phase, the following variants are disallowed:
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/// * [`TerminatorKind::DropAndReplace`](terminator::TerminatorKind::DropAndReplace)
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/// * [`TerminatorKind::FalseUnwind`](terminator::TerminatorKind::FalseUnwind)
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/// * [`TerminatorKind::FalseEdge`](terminator::TerminatorKind::FalseEdge)
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/// * [`StatementKind::FakeRead`]
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/// * [`StatementKind::AscribeUserType`]
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/// * [`Rvalue::Ref`] with `BorrowKind::Shallow`
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///
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/// And the following variant is allowed:
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/// * [`StatementKind::Retag`]
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///
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/// Furthermore, `Drop` now uses explicit drop flags visible in the MIR and reaching a `Drop`
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/// terminator means that the auto-generated drop glue will be invoked.
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DropsLowered = 3,
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/// Beginning with this phase, the following variant is disallowed:
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/// * [`Rvalue::Aggregate`] for any `AggregateKind` except `Array`
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///
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/// And the following variant is allowed:
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/// * [`StatementKind::SetDiscriminant`]
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Deaggregated = 4,
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/// Before this phase, generators are in the "source code" form, featuring `yield` statements
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/// and such. With this phase change, they are transformed into a proper state machine. Running
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/// optimizations before this change can be potentially dangerous because the source code is to
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/// some extent a "lie." In particular, `yield` terminators effectively make the value of all
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/// locals visible to the caller. This means that dead store elimination before them, or code
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/// motion across them, is not correct in general. This is also exasperated by type checking
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/// having pre-computed a list of the types that it thinks are ok to be live across a yield
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/// point - this is necessary to decide eg whether autotraits are implemented. Introducing new
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/// types across a yield point will lead to ICEs becaues of this.
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///
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/// Beginning with this phase, the following variants are disallowed:
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/// * [`TerminatorKind::Yield`](terminator::TerminatorKind::Yield)
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/// * [`TerminatorKind::GeneratorDrop](terminator::TerminatorKind::GeneratorDrop)
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GeneratorsLowered = 5,
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Optimized = 6,
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}
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impl MirPhase {
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/// Gets the index of the current MirPhase within the set of all `MirPhase`s.
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pub fn phase_index(&self) -> usize {
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*self as usize
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}
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}
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/// Where a specific `mir::Body` comes from.
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#[derive(Copy, Clone, Debug, PartialEq, Eq)]
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#[derive(HashStable, TyEncodable, TyDecodable, TypeFoldable)]
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pub struct MirSource<'tcx> {
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pub instance: InstanceDef<'tcx>,
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/// If `Some`, this is a promoted rvalue within the parent function.
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pub promoted: Option<Promoted>,
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}
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impl<'tcx> MirSource<'tcx> {
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pub fn item(def_id: DefId) -> Self {
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MirSource {
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instance: InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)),
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promoted: None,
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}
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}
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pub fn from_instance(instance: InstanceDef<'tcx>) -> Self {
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MirSource { instance, promoted: None }
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}
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pub fn with_opt_param(self) -> ty::WithOptConstParam<DefId> {
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self.instance.with_opt_param()
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}
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#[inline]
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pub fn def_id(&self) -> DefId {
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self.instance.def_id()
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}
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}
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#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable)]
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pub struct GeneratorInfo<'tcx> {
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/// The yield type of the function, if it is a generator.
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pub yield_ty: Option<Ty<'tcx>>,
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/// Generator drop glue.
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pub generator_drop: Option<Body<'tcx>>,
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/// The layout of a generator. Produced by the state transformation.
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pub generator_layout: Option<GeneratorLayout<'tcx>>,
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/// If this is a generator then record the type of source expression that caused this generator
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/// to be created.
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pub generator_kind: GeneratorKind,
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}
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/// The lowered representation of a single function.
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#[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable)]
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pub struct Body<'tcx> {
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/// A list of basic blocks. References to basic block use a newtyped index type [`BasicBlock`]
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/// that indexes into this vector.
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basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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/// Records how far through the "desugaring and optimization" process this particular
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/// MIR has traversed. This is particularly useful when inlining, since in that context
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/// we instantiate the promoted constants and add them to our promoted vector -- but those
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/// promoted items have already been optimized, whereas ours have not. This field allows
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/// us to see the difference and forego optimization on the inlined promoted items.
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pub phase: MirPhase,
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pub source: MirSource<'tcx>,
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/// A list of source scopes; these are referenced by statements
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/// and used for debuginfo. Indexed by a `SourceScope`.
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pub source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
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pub generator: Option<Box<GeneratorInfo<'tcx>>>,
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/// Declarations of locals.
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///
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/// The first local is the return value pointer, followed by `arg_count`
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/// locals for the function arguments, followed by any user-declared
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/// variables and temporaries.
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pub local_decls: LocalDecls<'tcx>,
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/// User type annotations.
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pub user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
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/// The number of arguments this function takes.
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///
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/// Starting at local 1, `arg_count` locals will be provided by the caller
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/// and can be assumed to be initialized.
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///
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/// If this MIR was built for a constant, this will be 0.
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pub arg_count: usize,
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/// Mark an argument local (which must be a tuple) as getting passed as
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/// its individual components at the LLVM level.
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///
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/// This is used for the "rust-call" ABI.
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pub spread_arg: Option<Local>,
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/// Debug information pertaining to user variables, including captures.
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pub var_debug_info: Vec<VarDebugInfo<'tcx>>,
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/// A span representing this MIR, for error reporting.
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pub span: Span,
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/// Constants that are required to evaluate successfully for this MIR to be well-formed.
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/// We hold in this field all the constants we are not able to evaluate yet.
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pub required_consts: Vec<Constant<'tcx>>,
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/// Does this body use generic parameters. This is used for the `ConstEvaluatable` check.
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///
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/// Note that this does not actually mean that this body is not computable right now.
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/// The repeat count in the following example is polymorphic, but can still be evaluated
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/// without knowing anything about the type parameter `T`.
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///
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/// ```rust
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/// fn test<T>() {
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/// let _ = [0; std::mem::size_of::<*mut T>()];
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/// }
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/// ```
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///
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/// **WARNING**: Do not change this flags after the MIR was originally created, even if an optimization
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/// removed the last mention of all generic params. We do not want to rely on optimizations and
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/// potentially allow things like `[u8; std::mem::size_of::<T>() * 0]` due to this.
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pub is_polymorphic: bool,
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predecessor_cache: PredecessorCache,
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switch_source_cache: SwitchSourceCache,
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is_cyclic: GraphIsCyclicCache,
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pub tainted_by_errors: Option<ErrorGuaranteed>,
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}
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impl<'tcx> Body<'tcx> {
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pub fn new(
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source: MirSource<'tcx>,
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basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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source_scopes: IndexVec<SourceScope, SourceScopeData<'tcx>>,
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local_decls: LocalDecls<'tcx>,
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user_type_annotations: ty::CanonicalUserTypeAnnotations<'tcx>,
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arg_count: usize,
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var_debug_info: Vec<VarDebugInfo<'tcx>>,
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span: Span,
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generator_kind: Option<GeneratorKind>,
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tainted_by_errors: Option<ErrorGuaranteed>,
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) -> Self {
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// We need `arg_count` locals, and one for the return place.
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assert!(
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local_decls.len() > arg_count,
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"expected at least {} locals, got {}",
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arg_count + 1,
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local_decls.len()
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);
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let mut body = Body {
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phase: MirPhase::Built,
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source,
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basic_blocks,
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source_scopes,
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generator: generator_kind.map(|generator_kind| {
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Box::new(GeneratorInfo {
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yield_ty: None,
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generator_drop: None,
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generator_layout: None,
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generator_kind,
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})
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}),
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local_decls,
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user_type_annotations,
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arg_count,
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spread_arg: None,
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var_debug_info,
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span,
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required_consts: Vec::new(),
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is_polymorphic: false,
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predecessor_cache: PredecessorCache::new(),
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switch_source_cache: SwitchSourceCache::new(),
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is_cyclic: GraphIsCyclicCache::new(),
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tainted_by_errors,
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};
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body.is_polymorphic = body.has_param_types_or_consts();
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body
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}
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/// Returns a partially initialized MIR body containing only a list of basic blocks.
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///
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/// The returned MIR contains no `LocalDecl`s (even for the return place) or source scopes. It
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/// is only useful for testing but cannot be `#[cfg(test)]` because it is used in a different
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/// crate.
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pub fn new_cfg_only(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>) -> Self {
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let mut body = Body {
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phase: MirPhase::Built,
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source: MirSource::item(CRATE_DEF_ID.to_def_id()),
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basic_blocks,
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source_scopes: IndexVec::new(),
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generator: None,
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local_decls: IndexVec::new(),
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user_type_annotations: IndexVec::new(),
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arg_count: 0,
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spread_arg: None,
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span: DUMMY_SP,
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required_consts: Vec::new(),
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var_debug_info: Vec::new(),
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is_polymorphic: false,
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predecessor_cache: PredecessorCache::new(),
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switch_source_cache: SwitchSourceCache::new(),
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is_cyclic: GraphIsCyclicCache::new(),
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tainted_by_errors: None,
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};
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body.is_polymorphic = body.has_param_types_or_consts();
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body
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}
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#[inline]
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pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
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&self.basic_blocks
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}
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#[inline]
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pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
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// Because the user could mutate basic block terminators via this reference, we need to
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// invalidate the caches.
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//
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// FIXME: Use a finer-grained API for this, so only transformations that alter terminators
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// invalidate the caches.
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self.predecessor_cache.invalidate();
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self.switch_source_cache.invalidate();
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self.is_cyclic.invalidate();
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&mut self.basic_blocks
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}
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#[inline]
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pub fn basic_blocks_and_local_decls_mut(
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&mut self,
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) -> (&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>, &mut LocalDecls<'tcx>) {
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self.predecessor_cache.invalidate();
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self.switch_source_cache.invalidate();
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self.is_cyclic.invalidate();
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(&mut self.basic_blocks, &mut self.local_decls)
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}
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#[inline]
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pub fn basic_blocks_local_decls_mut_and_var_debug_info(
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&mut self,
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) -> (
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&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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&mut LocalDecls<'tcx>,
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&mut Vec<VarDebugInfo<'tcx>>,
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) {
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self.predecessor_cache.invalidate();
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self.switch_source_cache.invalidate();
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self.is_cyclic.invalidate();
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(&mut self.basic_blocks, &mut self.local_decls, &mut self.var_debug_info)
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}
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/// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
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/// `START_BLOCK`.
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pub fn is_cfg_cyclic(&self) -> bool {
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self.is_cyclic.is_cyclic(self)
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}
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#[inline]
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pub fn local_kind(&self, local: Local) -> LocalKind {
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let index = local.as_usize();
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if index == 0 {
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debug_assert!(
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self.local_decls[local].mutability == Mutability::Mut,
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"return place should be mutable"
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);
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|
|
|
LocalKind::ReturnPointer
|
|
} else if index < self.arg_count + 1 {
|
|
LocalKind::Arg
|
|
} else if self.local_decls[local].is_user_variable() {
|
|
LocalKind::Var
|
|
} else {
|
|
LocalKind::Temp
|
|
}
|
|
}
|
|
|
|
/// Returns an iterator over all user-declared mutable locals.
|
|
#[inline]
|
|
pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
|
|
(self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
|
|
let local = Local::new(index);
|
|
let decl = &self.local_decls[local];
|
|
if decl.is_user_variable() && decl.mutability == Mutability::Mut {
|
|
Some(local)
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
}
|
|
|
|
/// Returns an iterator over all user-declared mutable arguments and locals.
|
|
#[inline]
|
|
pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
|
|
(1..self.local_decls.len()).filter_map(move |index| {
|
|
let local = Local::new(index);
|
|
let decl = &self.local_decls[local];
|
|
if (decl.is_user_variable() || index < self.arg_count + 1)
|
|
&& decl.mutability == Mutability::Mut
|
|
{
|
|
Some(local)
|
|
} else {
|
|
None
|
|
}
|
|
})
|
|
}
|
|
|
|
/// Returns an iterator over all function arguments.
|
|
#[inline]
|
|
pub fn args_iter(&self) -> impl Iterator<Item = Local> + ExactSizeIterator {
|
|
(1..self.arg_count + 1).map(Local::new)
|
|
}
|
|
|
|
/// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
|
|
/// locals that are neither arguments nor the return place).
|
|
#[inline]
|
|
pub fn vars_and_temps_iter(
|
|
&self,
|
|
) -> impl DoubleEndedIterator<Item = Local> + ExactSizeIterator {
|
|
(self.arg_count + 1..self.local_decls.len()).map(Local::new)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn drain_vars_and_temps<'a>(&'a mut self) -> impl Iterator<Item = LocalDecl<'tcx>> + 'a {
|
|
self.local_decls.drain(self.arg_count + 1..)
|
|
}
|
|
|
|
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
|
|
/// invalidating statement indices in `Location`s.
|
|
pub fn make_statement_nop(&mut self, location: Location) {
|
|
let block = &mut self.basic_blocks[location.block];
|
|
debug_assert!(location.statement_index < block.statements.len());
|
|
block.statements[location.statement_index].make_nop()
|
|
}
|
|
|
|
/// Returns the source info associated with `location`.
|
|
pub fn source_info(&self, location: Location) -> &SourceInfo {
|
|
let block = &self[location.block];
|
|
let stmts = &block.statements;
|
|
let idx = location.statement_index;
|
|
if idx < stmts.len() {
|
|
&stmts[idx].source_info
|
|
} else {
|
|
assert_eq!(idx, stmts.len());
|
|
&block.terminator().source_info
|
|
}
|
|
}
|
|
|
|
/// Returns the return type; it always return first element from `local_decls` array.
|
|
#[inline]
|
|
pub fn return_ty(&self) -> Ty<'tcx> {
|
|
self.local_decls[RETURN_PLACE].ty
|
|
}
|
|
|
|
/// Gets the location of the terminator for the given block.
|
|
#[inline]
|
|
pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
|
|
Location { block: bb, statement_index: self[bb].statements.len() }
|
|
}
|
|
|
|
pub fn stmt_at(&self, location: Location) -> Either<&Statement<'tcx>, &Terminator<'tcx>> {
|
|
let Location { block, statement_index } = location;
|
|
let block_data = &self.basic_blocks[block];
|
|
block_data
|
|
.statements
|
|
.get(statement_index)
|
|
.map(Either::Left)
|
|
.unwrap_or_else(|| Either::Right(block_data.terminator()))
|
|
}
|
|
|
|
#[inline]
|
|
pub fn predecessors(&self) -> &Predecessors {
|
|
self.predecessor_cache.compute(&self.basic_blocks)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn switch_sources(&self) -> &SwitchSources {
|
|
self.switch_source_cache.compute(&self.basic_blocks)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn dominators(&self) -> Dominators<BasicBlock> {
|
|
dominators(self)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn yield_ty(&self) -> Option<Ty<'tcx>> {
|
|
self.generator.as_ref().and_then(|generator| generator.yield_ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn generator_layout(&self) -> Option<&GeneratorLayout<'tcx>> {
|
|
self.generator.as_ref().and_then(|generator| generator.generator_layout.as_ref())
|
|
}
|
|
|
|
#[inline]
|
|
pub fn generator_drop(&self) -> Option<&Body<'tcx>> {
|
|
self.generator.as_ref().and_then(|generator| generator.generator_drop.as_ref())
|
|
}
|
|
|
|
#[inline]
|
|
pub fn generator_kind(&self) -> Option<GeneratorKind> {
|
|
self.generator.as_ref().map(|generator| generator.generator_kind)
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, PartialEq, Eq, Debug, TyEncodable, TyDecodable, HashStable)]
|
|
pub enum Safety {
|
|
Safe,
|
|
/// Unsafe because of compiler-generated unsafe code, like `await` desugaring
|
|
BuiltinUnsafe,
|
|
/// Unsafe because of an unsafe fn
|
|
FnUnsafe,
|
|
/// Unsafe because of an `unsafe` block
|
|
ExplicitUnsafe(hir::HirId),
|
|
}
|
|
|
|
impl<'tcx> Index<BasicBlock> for Body<'tcx> {
|
|
type Output = BasicBlockData<'tcx>;
|
|
|
|
#[inline]
|
|
fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
|
|
&self.basic_blocks()[index]
|
|
}
|
|
}
|
|
|
|
impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
|
|
#[inline]
|
|
fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
|
|
&mut self.basic_blocks_mut()[index]
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
|
|
pub enum ClearCrossCrate<T> {
|
|
Clear,
|
|
Set(T),
|
|
}
|
|
|
|
impl<T> ClearCrossCrate<T> {
|
|
pub fn as_ref(&self) -> ClearCrossCrate<&T> {
|
|
match self {
|
|
ClearCrossCrate::Clear => ClearCrossCrate::Clear,
|
|
ClearCrossCrate::Set(v) => ClearCrossCrate::Set(v),
|
|
}
|
|
}
|
|
|
|
pub fn assert_crate_local(self) -> T {
|
|
match self {
|
|
ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
|
|
ClearCrossCrate::Set(v) => v,
|
|
}
|
|
}
|
|
}
|
|
|
|
const TAG_CLEAR_CROSS_CRATE_CLEAR: u8 = 0;
|
|
const TAG_CLEAR_CROSS_CRATE_SET: u8 = 1;
|
|
|
|
impl<'tcx, E: TyEncoder<'tcx>, T: Encodable<E>> Encodable<E> for ClearCrossCrate<T> {
|
|
#[inline]
|
|
fn encode(&self, e: &mut E) -> Result<(), E::Error> {
|
|
if E::CLEAR_CROSS_CRATE {
|
|
return Ok(());
|
|
}
|
|
|
|
match *self {
|
|
ClearCrossCrate::Clear => TAG_CLEAR_CROSS_CRATE_CLEAR.encode(e),
|
|
ClearCrossCrate::Set(ref val) => {
|
|
TAG_CLEAR_CROSS_CRATE_SET.encode(e)?;
|
|
val.encode(e)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
impl<'tcx, D: TyDecoder<'tcx>, T: Decodable<D>> Decodable<D> for ClearCrossCrate<T> {
|
|
#[inline]
|
|
fn decode(d: &mut D) -> ClearCrossCrate<T> {
|
|
if D::CLEAR_CROSS_CRATE {
|
|
return ClearCrossCrate::Clear;
|
|
}
|
|
|
|
let discr = u8::decode(d);
|
|
|
|
match discr {
|
|
TAG_CLEAR_CROSS_CRATE_CLEAR => ClearCrossCrate::Clear,
|
|
TAG_CLEAR_CROSS_CRATE_SET => {
|
|
let val = T::decode(d);
|
|
ClearCrossCrate::Set(val)
|
|
}
|
|
tag => panic!("Invalid tag for ClearCrossCrate: {:?}", tag),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Grouped information about the source code origin of a MIR entity.
|
|
/// Intended to be inspected by diagnostics and debuginfo.
|
|
/// Most passes can work with it as a whole, within a single function.
|
|
// The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
|
|
// `Hash`. Please ping @bjorn3 if removing them.
|
|
#[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub struct SourceInfo {
|
|
/// The source span for the AST pertaining to this MIR entity.
|
|
pub span: Span,
|
|
|
|
/// The source scope, keeping track of which bindings can be
|
|
/// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
|
|
pub scope: SourceScope,
|
|
}
|
|
|
|
impl SourceInfo {
|
|
#[inline]
|
|
pub fn outermost(span: Span) -> Self {
|
|
SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE }
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Borrow kinds
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, TyEncodable, TyDecodable)]
|
|
#[derive(Hash, HashStable)]
|
|
pub enum BorrowKind {
|
|
/// Data must be immutable and is aliasable.
|
|
Shared,
|
|
|
|
/// The immediately borrowed place must be immutable, but projections from
|
|
/// it don't need to be. For example, a shallow borrow of `a.b` doesn't
|
|
/// conflict with a mutable borrow of `a.b.c`.
|
|
///
|
|
/// This is used when lowering matches: when matching on a place we want to
|
|
/// ensure that place have the same value from the start of the match until
|
|
/// an arm is selected. This prevents this code from compiling:
|
|
///
|
|
/// let mut x = &Some(0);
|
|
/// match *x {
|
|
/// None => (),
|
|
/// Some(_) if { x = &None; false } => (),
|
|
/// Some(_) => (),
|
|
/// }
|
|
///
|
|
/// This can't be a shared borrow because mutably borrowing (*x as Some).0
|
|
/// should not prevent `if let None = x { ... }`, for example, because the
|
|
/// mutating `(*x as Some).0` can't affect the discriminant of `x`.
|
|
/// We can also report errors with this kind of borrow differently.
|
|
Shallow,
|
|
|
|
/// Data must be immutable but not aliasable. This kind of borrow
|
|
/// cannot currently be expressed by the user and is used only in
|
|
/// implicit closure bindings. It is needed when the closure is
|
|
/// borrowing or mutating a mutable referent, e.g.:
|
|
///
|
|
/// let x: &mut isize = ...;
|
|
/// let y = || *x += 5;
|
|
///
|
|
/// If we were to try to translate this closure into a more explicit
|
|
/// form, we'd encounter an error with the code as written:
|
|
///
|
|
/// struct Env { x: & &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// This is then illegal because you cannot mutate an `&mut` found
|
|
/// in an aliasable location. To solve, you'd have to translate with
|
|
/// an `&mut` borrow:
|
|
///
|
|
/// struct Env { x: &mut &mut isize }
|
|
/// let x: &mut isize = ...;
|
|
/// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
|
|
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
|
///
|
|
/// Now the assignment to `**env.x` is legal, but creating a
|
|
/// mutable pointer to `x` is not because `x` is not mutable. We
|
|
/// could fix this by declaring `x` as `let mut x`. This is ok in
|
|
/// user code, if awkward, but extra weird for closures, since the
|
|
/// borrow is hidden.
|
|
///
|
|
/// So we introduce a "unique imm" borrow -- the referent is
|
|
/// immutable, but not aliasable. This solves the problem. For
|
|
/// simplicity, we don't give users the way to express this
|
|
/// borrow, it's just used when translating closures.
|
|
Unique,
|
|
|
|
/// Data is mutable and not aliasable.
|
|
Mut {
|
|
/// `true` if this borrow arose from method-call auto-ref
|
|
/// (i.e., `adjustment::Adjust::Borrow`).
|
|
allow_two_phase_borrow: bool,
|
|
},
|
|
}
|
|
|
|
impl BorrowKind {
|
|
pub fn allows_two_phase_borrow(&self) -> bool {
|
|
match *self {
|
|
BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
|
|
BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
|
|
}
|
|
}
|
|
|
|
pub fn describe_mutability(&self) -> String {
|
|
match *self {
|
|
BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => {
|
|
"immutable".to_string()
|
|
}
|
|
BorrowKind::Mut { .. } => "mutable".to_string(),
|
|
}
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Variables and temps
|
|
|
|
rustc_index::newtype_index! {
|
|
pub struct Local {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "_{}",
|
|
const RETURN_PLACE = 0,
|
|
}
|
|
}
|
|
|
|
impl Atom for Local {
|
|
fn index(self) -> usize {
|
|
Idx::index(self)
|
|
}
|
|
}
|
|
|
|
/// Classifies locals into categories. See `Body::local_kind`.
|
|
#[derive(Clone, Copy, PartialEq, Eq, Debug, HashStable)]
|
|
pub enum LocalKind {
|
|
/// User-declared variable binding.
|
|
Var,
|
|
/// Compiler-introduced temporary.
|
|
Temp,
|
|
/// Function argument.
|
|
Arg,
|
|
/// Location of function's return value.
|
|
ReturnPointer,
|
|
}
|
|
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
|
|
pub struct VarBindingForm<'tcx> {
|
|
/// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
|
|
pub binding_mode: ty::BindingMode,
|
|
/// If an explicit type was provided for this variable binding,
|
|
/// this holds the source Span of that type.
|
|
///
|
|
/// NOTE: if you want to change this to a `HirId`, be wary that
|
|
/// doing so breaks incremental compilation (as of this writing),
|
|
/// while a `Span` does not cause our tests to fail.
|
|
pub opt_ty_info: Option<Span>,
|
|
/// Place of the RHS of the =, or the subject of the `match` where this
|
|
/// variable is initialized. None in the case of `let PATTERN;`.
|
|
/// Some((None, ..)) in the case of and `let [mut] x = ...` because
|
|
/// (a) the right-hand side isn't evaluated as a place expression.
|
|
/// (b) it gives a way to separate this case from the remaining cases
|
|
/// for diagnostics.
|
|
pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
|
|
/// The span of the pattern in which this variable was bound.
|
|
pub pat_span: Span,
|
|
}
|
|
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable)]
|
|
pub enum BindingForm<'tcx> {
|
|
/// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
|
|
Var(VarBindingForm<'tcx>),
|
|
/// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
|
|
ImplicitSelf(ImplicitSelfKind),
|
|
/// Reference used in a guard expression to ensure immutability.
|
|
RefForGuard,
|
|
}
|
|
|
|
/// Represents what type of implicit self a function has, if any.
|
|
#[derive(Clone, Copy, PartialEq, Debug, TyEncodable, TyDecodable, HashStable)]
|
|
pub enum ImplicitSelfKind {
|
|
/// Represents a `fn x(self);`.
|
|
Imm,
|
|
/// Represents a `fn x(mut self);`.
|
|
Mut,
|
|
/// Represents a `fn x(&self);`.
|
|
ImmRef,
|
|
/// Represents a `fn x(&mut self);`.
|
|
MutRef,
|
|
/// Represents when a function does not have a self argument or
|
|
/// when a function has a `self: X` argument.
|
|
None,
|
|
}
|
|
|
|
TrivialTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
|
|
|
|
mod binding_form_impl {
|
|
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
|
|
use rustc_query_system::ich::StableHashingContext;
|
|
|
|
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
|
|
fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
|
|
use super::BindingForm::*;
|
|
std::mem::discriminant(self).hash_stable(hcx, hasher);
|
|
|
|
match self {
|
|
Var(binding) => binding.hash_stable(hcx, hasher),
|
|
ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
|
|
RefForGuard => (),
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
|
|
/// created during evaluation of expressions in a block tail
|
|
/// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
|
|
///
|
|
/// It is used to improve diagnostics when such temporaries are
|
|
/// involved in borrow_check errors, e.g., explanations of where the
|
|
/// temporaries come from, when their destructors are run, and/or how
|
|
/// one might revise the code to satisfy the borrow checker's rules.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
|
|
pub struct BlockTailInfo {
|
|
/// If `true`, then the value resulting from evaluating this tail
|
|
/// expression is ignored by the block's expression context.
|
|
///
|
|
/// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
|
|
/// but not e.g., `let _x = { ...; tail };`
|
|
pub tail_result_is_ignored: bool,
|
|
|
|
/// `Span` of the tail expression.
|
|
pub span: Span,
|
|
}
|
|
|
|
/// A MIR local.
|
|
///
|
|
/// This can be a binding declared by the user, a temporary inserted by the compiler, a function
|
|
/// argument, or the return place.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct LocalDecl<'tcx> {
|
|
/// Whether this is a mutable binding (i.e., `let x` or `let mut x`).
|
|
///
|
|
/// Temporaries and the return place are always mutable.
|
|
pub mutability: Mutability,
|
|
|
|
// FIXME(matthewjasper) Don't store in this in `Body`
|
|
pub local_info: Option<Box<LocalInfo<'tcx>>>,
|
|
|
|
/// `true` if this is an internal local.
|
|
///
|
|
/// These locals are not based on types in the source code and are only used
|
|
/// for a few desugarings at the moment.
|
|
///
|
|
/// The generator transformation will sanity check the locals which are live
|
|
/// across a suspension point against the type components of the generator
|
|
/// which type checking knows are live across a suspension point. We need to
|
|
/// flag drop flags to avoid triggering this check as they are introduced
|
|
/// outside of type inference.
|
|
///
|
|
/// This should be sound because the drop flags are fully algebraic, and
|
|
/// therefore don't affect the auto-trait or outlives properties of the
|
|
/// generator.
|
|
pub internal: bool,
|
|
|
|
/// If this local is a temporary and `is_block_tail` is `Some`,
|
|
/// then it is a temporary created for evaluation of some
|
|
/// subexpression of some block's tail expression (with no
|
|
/// intervening statement context).
|
|
// FIXME(matthewjasper) Don't store in this in `Body`
|
|
pub is_block_tail: Option<BlockTailInfo>,
|
|
|
|
/// The type of this local.
|
|
pub ty: Ty<'tcx>,
|
|
|
|
/// If the user manually ascribed a type to this variable,
|
|
/// e.g., via `let x: T`, then we carry that type here. The MIR
|
|
/// borrow checker needs this information since it can affect
|
|
/// region inference.
|
|
// FIXME(matthewjasper) Don't store in this in `Body`
|
|
pub user_ty: Option<Box<UserTypeProjections>>,
|
|
|
|
/// The *syntactic* (i.e., not visibility) source scope the local is defined
|
|
/// in. If the local was defined in a let-statement, this
|
|
/// is *within* the let-statement, rather than outside
|
|
/// of it.
|
|
///
|
|
/// This is needed because the visibility source scope of locals within
|
|
/// a let-statement is weird.
|
|
///
|
|
/// The reason is that we want the local to be *within* the let-statement
|
|
/// for lint purposes, but we want the local to be *after* the let-statement
|
|
/// for names-in-scope purposes.
|
|
///
|
|
/// That's it, if we have a let-statement like the one in this
|
|
/// function:
|
|
///
|
|
/// ```
|
|
/// fn foo(x: &str) {
|
|
/// #[allow(unused_mut)]
|
|
/// let mut x: u32 = { // <- one unused mut
|
|
/// let mut y: u32 = x.parse().unwrap();
|
|
/// y + 2
|
|
/// };
|
|
/// drop(x);
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// Then, from a lint point of view, the declaration of `x: u32`
|
|
/// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
|
|
/// lint scopes are the same as the AST/HIR nesting.
|
|
///
|
|
/// However, from a name lookup point of view, the scopes look more like
|
|
/// as if the let-statements were `match` expressions:
|
|
///
|
|
/// ```
|
|
/// fn foo(x: &str) {
|
|
/// match {
|
|
/// match x.parse().unwrap() {
|
|
/// y => y + 2
|
|
/// }
|
|
/// } {
|
|
/// x => drop(x)
|
|
/// };
|
|
/// }
|
|
/// ```
|
|
///
|
|
/// We care about the name-lookup scopes for debuginfo - if the
|
|
/// debuginfo instruction pointer is at the call to `x.parse()`, we
|
|
/// want `x` to refer to `x: &str`, but if it is at the call to
|
|
/// `drop(x)`, we want it to refer to `x: u32`.
|
|
///
|
|
/// To allow both uses to work, we need to have more than a single scope
|
|
/// for a local. We have the `source_info.scope` represent the "syntactic"
|
|
/// lint scope (with a variable being under its let block) while the
|
|
/// `var_debug_info.source_info.scope` represents the "local variable"
|
|
/// scope (where the "rest" of a block is under all prior let-statements).
|
|
///
|
|
/// The end result looks like this:
|
|
///
|
|
/// ```text
|
|
/// ROOT SCOPE
|
|
/// │{ argument x: &str }
|
|
/// │
|
|
/// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
|
|
/// │ │ // in practice because I'm lazy.
|
|
/// │ │
|
|
/// │ │← x.source_info.scope
|
|
/// │ │← `x.parse().unwrap()`
|
|
/// │ │
|
|
/// │ │ │← y.source_info.scope
|
|
/// │ │
|
|
/// │ │ │{ let y: u32 }
|
|
/// │ │ │
|
|
/// │ │ │← y.var_debug_info.source_info.scope
|
|
/// │ │ │← `y + 2`
|
|
/// │
|
|
/// │ │{ let x: u32 }
|
|
/// │ │← x.var_debug_info.source_info.scope
|
|
/// │ │← `drop(x)` // This accesses `x: u32`.
|
|
/// ```
|
|
pub source_info: SourceInfo,
|
|
}
|
|
|
|
// `LocalDecl` is used a lot. Make sure it doesn't unintentionally get bigger.
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(LocalDecl<'_>, 56);
|
|
|
|
/// Extra information about a some locals that's used for diagnostics and for
|
|
/// classifying variables into local variables, statics, etc, which is needed e.g.
|
|
/// for unsafety checking.
|
|
///
|
|
/// Not used for non-StaticRef temporaries, the return place, or anonymous
|
|
/// function parameters.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub enum LocalInfo<'tcx> {
|
|
/// A user-defined local variable or function parameter
|
|
///
|
|
/// The `BindingForm` is solely used for local diagnostics when generating
|
|
/// warnings/errors when compiling the current crate, and therefore it need
|
|
/// not be visible across crates.
|
|
User(ClearCrossCrate<BindingForm<'tcx>>),
|
|
/// A temporary created that references the static with the given `DefId`.
|
|
StaticRef { def_id: DefId, is_thread_local: bool },
|
|
/// A temporary created that references the const with the given `DefId`
|
|
ConstRef { def_id: DefId },
|
|
/// A temporary created during the creation of an aggregate
|
|
/// (e.g. a temporary for `foo` in `MyStruct { my_field: foo }`)
|
|
AggregateTemp,
|
|
}
|
|
|
|
impl<'tcx> LocalDecl<'tcx> {
|
|
/// Returns `true` only if local is a binding that can itself be
|
|
/// made mutable via the addition of the `mut` keyword, namely
|
|
/// something like the occurrences of `x` in:
|
|
/// - `fn foo(x: Type) { ... }`,
|
|
/// - `let x = ...`,
|
|
/// - or `match ... { C(x) => ... }`
|
|
pub fn can_be_made_mutable(&self) -> bool {
|
|
matches!(
|
|
self.local_info,
|
|
Some(box LocalInfo::User(ClearCrossCrate::Set(
|
|
BindingForm::Var(VarBindingForm {
|
|
binding_mode: ty::BindingMode::BindByValue(_),
|
|
opt_ty_info: _,
|
|
opt_match_place: _,
|
|
pat_span: _,
|
|
}) | BindingForm::ImplicitSelf(ImplicitSelfKind::Imm),
|
|
)))
|
|
)
|
|
}
|
|
|
|
/// Returns `true` if local is definitely not a `ref ident` or
|
|
/// `ref mut ident` binding. (Such bindings cannot be made into
|
|
/// mutable bindings, but the inverse does not necessarily hold).
|
|
pub fn is_nonref_binding(&self) -> bool {
|
|
matches!(
|
|
self.local_info,
|
|
Some(box LocalInfo::User(ClearCrossCrate::Set(
|
|
BindingForm::Var(VarBindingForm {
|
|
binding_mode: ty::BindingMode::BindByValue(_),
|
|
opt_ty_info: _,
|
|
opt_match_place: _,
|
|
pat_span: _,
|
|
}) | BindingForm::ImplicitSelf(_),
|
|
)))
|
|
)
|
|
}
|
|
|
|
/// Returns `true` if this variable is a named variable or function
|
|
/// parameter declared by the user.
|
|
#[inline]
|
|
pub fn is_user_variable(&self) -> bool {
|
|
matches!(self.local_info, Some(box LocalInfo::User(_)))
|
|
}
|
|
|
|
/// Returns `true` if this is a reference to a variable bound in a `match`
|
|
/// expression that is used to access said variable for the guard of the
|
|
/// match arm.
|
|
pub fn is_ref_for_guard(&self) -> bool {
|
|
matches!(
|
|
self.local_info,
|
|
Some(box LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)))
|
|
)
|
|
}
|
|
|
|
/// Returns `Some` if this is a reference to a static item that is used to
|
|
/// access that static.
|
|
pub fn is_ref_to_static(&self) -> bool {
|
|
matches!(self.local_info, Some(box LocalInfo::StaticRef { .. }))
|
|
}
|
|
|
|
/// Returns `Some` if this is a reference to a thread-local static item that is used to
|
|
/// access that static.
|
|
pub fn is_ref_to_thread_local(&self) -> bool {
|
|
match self.local_info {
|
|
Some(box LocalInfo::StaticRef { is_thread_local, .. }) => is_thread_local,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// Returns `true` is the local is from a compiler desugaring, e.g.,
|
|
/// `__next` from a `for` loop.
|
|
#[inline]
|
|
pub fn from_compiler_desugaring(&self) -> bool {
|
|
self.source_info.span.desugaring_kind().is_some()
|
|
}
|
|
|
|
/// Creates a new `LocalDecl` for a temporary: mutable, non-internal.
|
|
#[inline]
|
|
pub fn new(ty: Ty<'tcx>, span: Span) -> Self {
|
|
Self::with_source_info(ty, SourceInfo::outermost(span))
|
|
}
|
|
|
|
/// Like `LocalDecl::new`, but takes a `SourceInfo` instead of a `Span`.
|
|
#[inline]
|
|
pub fn with_source_info(ty: Ty<'tcx>, source_info: SourceInfo) -> Self {
|
|
LocalDecl {
|
|
mutability: Mutability::Mut,
|
|
local_info: None,
|
|
internal: false,
|
|
is_block_tail: None,
|
|
ty,
|
|
user_ty: None,
|
|
source_info,
|
|
}
|
|
}
|
|
|
|
/// Converts `self` into same `LocalDecl` except tagged as internal.
|
|
#[inline]
|
|
pub fn internal(mut self) -> Self {
|
|
self.internal = true;
|
|
self
|
|
}
|
|
|
|
/// Converts `self` into same `LocalDecl` except tagged as immutable.
|
|
#[inline]
|
|
pub fn immutable(mut self) -> Self {
|
|
self.mutability = Mutability::Not;
|
|
self
|
|
}
|
|
|
|
/// Converts `self` into same `LocalDecl` except tagged as internal temporary.
|
|
#[inline]
|
|
pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
|
|
assert!(self.is_block_tail.is_none());
|
|
self.is_block_tail = Some(info);
|
|
self
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub enum VarDebugInfoContents<'tcx> {
|
|
/// NOTE(eddyb) There's an unenforced invariant that this `Place` is
|
|
/// based on a `Local`, not a `Static`, and contains no indexing.
|
|
Place(Place<'tcx>),
|
|
Const(Constant<'tcx>),
|
|
}
|
|
|
|
impl<'tcx> Debug for VarDebugInfoContents<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
match self {
|
|
VarDebugInfoContents::Const(c) => write!(fmt, "{}", c),
|
|
VarDebugInfoContents::Place(p) => write!(fmt, "{:?}", p),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Debug information pertaining to a user variable.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct VarDebugInfo<'tcx> {
|
|
pub name: Symbol,
|
|
|
|
/// Source info of the user variable, including the scope
|
|
/// within which the variable is visible (to debuginfo)
|
|
/// (see `LocalDecl`'s `source_info` field for more details).
|
|
pub source_info: SourceInfo,
|
|
|
|
/// Where the data for this user variable is to be found.
|
|
pub value: VarDebugInfoContents<'tcx>,
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// BasicBlock
|
|
|
|
rustc_index::newtype_index! {
|
|
/// A node in the MIR [control-flow graph][CFG].
|
|
///
|
|
/// There are no branches (e.g., `if`s, function calls, etc.) within a basic block, which makes
|
|
/// it easier to do [data-flow analyses] and optimizations. Instead, branches are represented
|
|
/// as an edge in a graph between basic blocks.
|
|
///
|
|
/// Basic blocks consist of a series of [statements][Statement], ending with a
|
|
/// [terminator][Terminator]. Basic blocks can have multiple predecessors and successors,
|
|
/// however there is a MIR pass ([`CriticalCallEdges`]) that removes *critical edges*, which
|
|
/// are edges that go from a multi-successor node to a multi-predecessor node. This pass is
|
|
/// needed because some analyses require that there are no critical edges in the CFG.
|
|
///
|
|
/// Note that this type is just an index into [`Body.basic_blocks`](Body::basic_blocks);
|
|
/// the actual data that a basic block holds is in [`BasicBlockData`].
|
|
///
|
|
/// Read more about basic blocks in the [rustc-dev-guide][guide-mir].
|
|
///
|
|
/// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
|
|
/// [data-flow analyses]:
|
|
/// https://rustc-dev-guide.rust-lang.org/appendix/background.html#what-is-a-dataflow-analysis
|
|
/// [`CriticalCallEdges`]: ../../rustc_const_eval/transform/add_call_guards/enum.AddCallGuards.html#variant.CriticalCallEdges
|
|
/// [guide-mir]: https://rustc-dev-guide.rust-lang.org/mir/
|
|
pub struct BasicBlock {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "bb{}",
|
|
const START_BLOCK = 0,
|
|
}
|
|
}
|
|
|
|
impl BasicBlock {
|
|
pub fn start_location(self) -> Location {
|
|
Location { block: self, statement_index: 0 }
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// BasicBlockData and Terminator
|
|
|
|
/// See [`BasicBlock`] for documentation on what basic blocks are at a high level.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct BasicBlockData<'tcx> {
|
|
/// List of statements in this block.
|
|
pub statements: Vec<Statement<'tcx>>,
|
|
|
|
/// Terminator for this block.
|
|
///
|
|
/// N.B., this should generally ONLY be `None` during construction.
|
|
/// Therefore, you should generally access it via the
|
|
/// `terminator()` or `terminator_mut()` methods. The only
|
|
/// exception is that certain passes, such as `simplify_cfg`, swap
|
|
/// out the terminator temporarily with `None` while they continue
|
|
/// to recurse over the set of basic blocks.
|
|
pub terminator: Option<Terminator<'tcx>>,
|
|
|
|
/// If true, this block lies on an unwind path. This is used
|
|
/// during codegen where distinct kinds of basic blocks may be
|
|
/// generated (particularly for MSVC cleanup). Unwind blocks must
|
|
/// only branch to other unwind blocks.
|
|
pub is_cleanup: bool,
|
|
}
|
|
|
|
/// Information about an assertion failure.
|
|
#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, PartialOrd)]
|
|
pub enum AssertKind<O> {
|
|
BoundsCheck { len: O, index: O },
|
|
Overflow(BinOp, O, O),
|
|
OverflowNeg(O),
|
|
DivisionByZero(O),
|
|
RemainderByZero(O),
|
|
ResumedAfterReturn(GeneratorKind),
|
|
ResumedAfterPanic(GeneratorKind),
|
|
}
|
|
|
|
#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
|
|
pub enum InlineAsmOperand<'tcx> {
|
|
In {
|
|
reg: InlineAsmRegOrRegClass,
|
|
value: Operand<'tcx>,
|
|
},
|
|
Out {
|
|
reg: InlineAsmRegOrRegClass,
|
|
late: bool,
|
|
place: Option<Place<'tcx>>,
|
|
},
|
|
InOut {
|
|
reg: InlineAsmRegOrRegClass,
|
|
late: bool,
|
|
in_value: Operand<'tcx>,
|
|
out_place: Option<Place<'tcx>>,
|
|
},
|
|
Const {
|
|
value: Box<Constant<'tcx>>,
|
|
},
|
|
SymFn {
|
|
value: Box<Constant<'tcx>>,
|
|
},
|
|
SymStatic {
|
|
def_id: DefId,
|
|
},
|
|
}
|
|
|
|
/// Type for MIR `Assert` terminator error messages.
|
|
pub type AssertMessage<'tcx> = AssertKind<Operand<'tcx>>;
|
|
|
|
// FIXME: Change `Successors` to `impl Iterator<Item = BasicBlock>`.
|
|
#[allow(rustc::pass_by_value)]
|
|
pub type Successors<'a> =
|
|
iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
|
|
pub type SuccessorsMut<'a> =
|
|
iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
|
|
|
|
impl<'tcx> BasicBlockData<'tcx> {
|
|
pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
|
|
BasicBlockData { statements: vec![], terminator, is_cleanup: false }
|
|
}
|
|
|
|
/// Accessor for terminator.
|
|
///
|
|
/// Terminator may not be None after construction of the basic block is complete. This accessor
|
|
/// provides a convenience way to reach the terminator.
|
|
#[inline]
|
|
pub fn terminator(&self) -> &Terminator<'tcx> {
|
|
self.terminator.as_ref().expect("invalid terminator state")
|
|
}
|
|
|
|
#[inline]
|
|
pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
|
|
self.terminator.as_mut().expect("invalid terminator state")
|
|
}
|
|
|
|
pub fn retain_statements<F>(&mut self, mut f: F)
|
|
where
|
|
F: FnMut(&mut Statement<'_>) -> bool,
|
|
{
|
|
for s in &mut self.statements {
|
|
if !f(s) {
|
|
s.make_nop();
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn expand_statements<F, I>(&mut self, mut f: F)
|
|
where
|
|
F: FnMut(&mut Statement<'tcx>) -> Option<I>,
|
|
I: iter::TrustedLen<Item = Statement<'tcx>>,
|
|
{
|
|
// Gather all the iterators we'll need to splice in, and their positions.
|
|
let mut splices: Vec<(usize, I)> = vec![];
|
|
let mut extra_stmts = 0;
|
|
for (i, s) in self.statements.iter_mut().enumerate() {
|
|
if let Some(mut new_stmts) = f(s) {
|
|
if let Some(first) = new_stmts.next() {
|
|
// We can already store the first new statement.
|
|
*s = first;
|
|
|
|
// Save the other statements for optimized splicing.
|
|
let remaining = new_stmts.size_hint().0;
|
|
if remaining > 0 {
|
|
splices.push((i + 1 + extra_stmts, new_stmts));
|
|
extra_stmts += remaining;
|
|
}
|
|
} else {
|
|
s.make_nop();
|
|
}
|
|
}
|
|
}
|
|
|
|
// Splice in the new statements, from the end of the block.
|
|
// FIXME(eddyb) This could be more efficient with a "gap buffer"
|
|
// where a range of elements ("gap") is left uninitialized, with
|
|
// splicing adding new elements to the end of that gap and moving
|
|
// existing elements from before the gap to the end of the gap.
|
|
// For now, this is safe code, emulating a gap but initializing it.
|
|
let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
|
|
self.statements.resize(
|
|
gap.end,
|
|
Statement { source_info: SourceInfo::outermost(DUMMY_SP), kind: StatementKind::Nop },
|
|
);
|
|
for (splice_start, new_stmts) in splices.into_iter().rev() {
|
|
let splice_end = splice_start + new_stmts.size_hint().0;
|
|
while gap.end > splice_end {
|
|
gap.start -= 1;
|
|
gap.end -= 1;
|
|
self.statements.swap(gap.start, gap.end);
|
|
}
|
|
self.statements.splice(splice_start..splice_end, new_stmts);
|
|
gap.end = splice_start;
|
|
}
|
|
}
|
|
|
|
pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
|
|
if index < self.statements.len() { &self.statements[index] } else { &self.terminator }
|
|
}
|
|
}
|
|
|
|
impl<O> AssertKind<O> {
|
|
/// Getting a description does not require `O` to be printable, and does not
|
|
/// require allocation.
|
|
/// The caller is expected to handle `BoundsCheck` separately.
|
|
pub fn description(&self) -> &'static str {
|
|
use AssertKind::*;
|
|
match self {
|
|
Overflow(BinOp::Add, _, _) => "attempt to add with overflow",
|
|
Overflow(BinOp::Sub, _, _) => "attempt to subtract with overflow",
|
|
Overflow(BinOp::Mul, _, _) => "attempt to multiply with overflow",
|
|
Overflow(BinOp::Div, _, _) => "attempt to divide with overflow",
|
|
Overflow(BinOp::Rem, _, _) => "attempt to calculate the remainder with overflow",
|
|
OverflowNeg(_) => "attempt to negate with overflow",
|
|
Overflow(BinOp::Shr, _, _) => "attempt to shift right with overflow",
|
|
Overflow(BinOp::Shl, _, _) => "attempt to shift left with overflow",
|
|
Overflow(op, _, _) => bug!("{:?} cannot overflow", op),
|
|
DivisionByZero(_) => "attempt to divide by zero",
|
|
RemainderByZero(_) => "attempt to calculate the remainder with a divisor of zero",
|
|
ResumedAfterReturn(GeneratorKind::Gen) => "generator resumed after completion",
|
|
ResumedAfterReturn(GeneratorKind::Async(_)) => "`async fn` resumed after completion",
|
|
ResumedAfterPanic(GeneratorKind::Gen) => "generator resumed after panicking",
|
|
ResumedAfterPanic(GeneratorKind::Async(_)) => "`async fn` resumed after panicking",
|
|
BoundsCheck { .. } => bug!("Unexpected AssertKind"),
|
|
}
|
|
}
|
|
|
|
/// Format the message arguments for the `assert(cond, msg..)` terminator in MIR printing.
|
|
pub fn fmt_assert_args<W: Write>(&self, f: &mut W) -> fmt::Result
|
|
where
|
|
O: Debug,
|
|
{
|
|
use AssertKind::*;
|
|
match self {
|
|
BoundsCheck { ref len, ref index } => write!(
|
|
f,
|
|
"\"index out of bounds: the length is {{}} but the index is {{}}\", {:?}, {:?}",
|
|
len, index
|
|
),
|
|
|
|
OverflowNeg(op) => {
|
|
write!(f, "\"attempt to negate `{{}}`, which would overflow\", {:?}", op)
|
|
}
|
|
DivisionByZero(op) => write!(f, "\"attempt to divide `{{}}` by zero\", {:?}", op),
|
|
RemainderByZero(op) => write!(
|
|
f,
|
|
"\"attempt to calculate the remainder of `{{}}` with a divisor of zero\", {:?}",
|
|
op
|
|
),
|
|
Overflow(BinOp::Add, l, r) => write!(
|
|
f,
|
|
"\"attempt to compute `{{}} + {{}}`, which would overflow\", {:?}, {:?}",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Sub, l, r) => write!(
|
|
f,
|
|
"\"attempt to compute `{{}} - {{}}`, which would overflow\", {:?}, {:?}",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Mul, l, r) => write!(
|
|
f,
|
|
"\"attempt to compute `{{}} * {{}}`, which would overflow\", {:?}, {:?}",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Div, l, r) => write!(
|
|
f,
|
|
"\"attempt to compute `{{}} / {{}}`, which would overflow\", {:?}, {:?}",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Rem, l, r) => write!(
|
|
f,
|
|
"\"attempt to compute the remainder of `{{}} % {{}}`, which would overflow\", {:?}, {:?}",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Shr, _, r) => {
|
|
write!(f, "\"attempt to shift right by `{{}}`, which would overflow\", {:?}", r)
|
|
}
|
|
Overflow(BinOp::Shl, _, r) => {
|
|
write!(f, "\"attempt to shift left by `{{}}`, which would overflow\", {:?}", r)
|
|
}
|
|
_ => write!(f, "\"{}\"", self.description()),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<O: fmt::Debug> fmt::Debug for AssertKind<O> {
|
|
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
use AssertKind::*;
|
|
match self {
|
|
BoundsCheck { ref len, ref index } => write!(
|
|
f,
|
|
"index out of bounds: the length is {:?} but the index is {:?}",
|
|
len, index
|
|
),
|
|
OverflowNeg(op) => write!(f, "attempt to negate `{:#?}`, which would overflow", op),
|
|
DivisionByZero(op) => write!(f, "attempt to divide `{:#?}` by zero", op),
|
|
RemainderByZero(op) => write!(
|
|
f,
|
|
"attempt to calculate the remainder of `{:#?}` with a divisor of zero",
|
|
op
|
|
),
|
|
Overflow(BinOp::Add, l, r) => {
|
|
write!(f, "attempt to compute `{:#?} + {:#?}`, which would overflow", l, r)
|
|
}
|
|
Overflow(BinOp::Sub, l, r) => {
|
|
write!(f, "attempt to compute `{:#?} - {:#?}`, which would overflow", l, r)
|
|
}
|
|
Overflow(BinOp::Mul, l, r) => {
|
|
write!(f, "attempt to compute `{:#?} * {:#?}`, which would overflow", l, r)
|
|
}
|
|
Overflow(BinOp::Div, l, r) => {
|
|
write!(f, "attempt to compute `{:#?} / {:#?}`, which would overflow", l, r)
|
|
}
|
|
Overflow(BinOp::Rem, l, r) => write!(
|
|
f,
|
|
"attempt to compute the remainder of `{:#?} % {:#?}`, which would overflow",
|
|
l, r
|
|
),
|
|
Overflow(BinOp::Shr, _, r) => {
|
|
write!(f, "attempt to shift right by `{:#?}`, which would overflow", r)
|
|
}
|
|
Overflow(BinOp::Shl, _, r) => {
|
|
write!(f, "attempt to shift left by `{:#?}`, which would overflow", r)
|
|
}
|
|
_ => write!(f, "{}", self.description()),
|
|
}
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Statements
|
|
|
|
#[derive(Clone, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct Statement<'tcx> {
|
|
pub source_info: SourceInfo,
|
|
pub kind: StatementKind<'tcx>,
|
|
}
|
|
|
|
// `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(Statement<'_>, 32);
|
|
|
|
impl Statement<'_> {
|
|
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
|
|
/// invalidating statement indices in `Location`s.
|
|
pub fn make_nop(&mut self) {
|
|
self.kind = StatementKind::Nop
|
|
}
|
|
|
|
/// Changes a statement to a nop and returns the original statement.
|
|
#[must_use = "If you don't need the statement, use `make_nop` instead"]
|
|
pub fn replace_nop(&mut self) -> Self {
|
|
Statement {
|
|
source_info: self.source_info,
|
|
kind: mem::replace(&mut self.kind, StatementKind::Nop),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// The various kinds of statements that can appear in MIR.
|
|
///
|
|
/// Not all of these are allowed at every [`MirPhase`]. Check the documentation there to see which
|
|
/// ones you do not have to worry about. The MIR validator will generally enforce such restrictions,
|
|
/// causing an ICE if they are violated.
|
|
#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
|
|
pub enum StatementKind<'tcx> {
|
|
/// Assign statements roughly correspond to an assignment in Rust proper (`x = ...`) except
|
|
/// without the possibility of dropping the previous value (that must be done separately, if at
|
|
/// all). The *exact* way this works is undecided. It probably does something like evaluating
|
|
/// the LHS to a place and the RHS to a value, and then storing the value to the place. Various
|
|
/// parts of this may do type specific things that are more complicated than simply copying
|
|
/// bytes.
|
|
///
|
|
/// **Needs clarification**: The implication of the above idea would be that assignment implies
|
|
/// that the resulting value is initialized. I believe we could commit to this separately from
|
|
/// committing to whatever part of the memory model we would need to decide on to make the above
|
|
/// paragragh precise. Do we want to?
|
|
///
|
|
/// Assignments in which the types of the place and rvalue differ are not well-formed.
|
|
///
|
|
/// **Needs clarification**: Do we ever want to worry about non-free (in the body) lifetimes for
|
|
/// the typing requirement in post drop-elaboration MIR? I think probably not - I'm not sure we
|
|
/// could meaningfully require this anyway. How about free lifetimes? Is ignoring this
|
|
/// interesting for optimizations? Do we want to allow such optimizations?
|
|
///
|
|
/// **Needs clarification**: We currently require that the LHS place not overlap with any place
|
|
/// read as part of computation of the RHS for some rvalues (generally those not producing
|
|
/// primitives). This requirement is under discussion in [#68364]. As a part of this discussion,
|
|
/// it is also unclear in what order the components are evaluated.
|
|
///
|
|
/// [#68364]: https://github.com/rust-lang/rust/issues/68364
|
|
///
|
|
/// See [`Rvalue`] documentation for details on each of those.
|
|
Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
|
|
|
|
/// This represents all the reading that a pattern match may do (e.g., inspecting constants and
|
|
/// discriminant values), and the kind of pattern it comes from. This is in order to adapt
|
|
/// potential error messages to these specific patterns.
|
|
///
|
|
/// Note that this also is emitted for regular `let` bindings to ensure that locals that are
|
|
/// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
|
|
///
|
|
/// When executed at runtime this is a nop.
|
|
///
|
|
/// Disallowed after drop elaboration.
|
|
FakeRead(Box<(FakeReadCause, Place<'tcx>)>),
|
|
|
|
/// Write the discriminant for a variant to the enum Place.
|
|
///
|
|
/// This is permitted for both generators and ADTs. This does not necessarily write to the
|
|
/// entire place; instead, it writes to the minimum set of bytes as required by the layout for
|
|
/// the type.
|
|
SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
|
|
|
|
/// Deinitializes the place.
|
|
///
|
|
/// This writes `uninit` bytes to the entire place.
|
|
Deinit(Box<Place<'tcx>>),
|
|
|
|
/// `StorageLive` and `StorageDead` statements mark the live range of a local.
|
|
///
|
|
/// Using a local before a `StorageLive` or after a `StorageDead` is not well-formed. These
|
|
/// statements are not required. If the entire MIR body contains no `StorageLive`/`StorageDead`
|
|
/// statements for a particular local, the local is always considered live.
|
|
///
|
|
/// More precisely, the MIR validator currently does a `MaybeStorageLiveLocals` analysis to
|
|
/// check validity of each use of a local. I believe this is equivalent to requiring for every
|
|
/// use of a local, there exist at least one path from the root to that use that contains a
|
|
/// `StorageLive` more recently than a `StorageDead`.
|
|
///
|
|
/// **Needs clarification**: Is it permitted to have two `StorageLive`s without an intervening
|
|
/// `StorageDead`? Two `StorageDead`s without an intervening `StorageLive`? LLVM says poison,
|
|
/// yes. If the answer to any of these is "no," is breaking that rule UB or is it an error to
|
|
/// have a path in the CFG that might do this?
|
|
StorageLive(Local),
|
|
|
|
/// See `StorageLive` above.
|
|
StorageDead(Local),
|
|
|
|
/// Retag references in the given place, ensuring they got fresh tags.
|
|
///
|
|
/// This is part of the Stacked Borrows model. These statements are currently only interpreted
|
|
/// by miri and only generated when `-Z mir-emit-retag` is passed. See
|
|
/// <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/> for
|
|
/// more details.
|
|
///
|
|
/// For code that is not specific to stacked borrows, you should consider retags to read
|
|
/// and modify the place in an opaque way.
|
|
Retag(RetagKind, Box<Place<'tcx>>),
|
|
|
|
/// Encodes a user's type ascription. These need to be preserved
|
|
/// intact so that NLL can respect them. For example:
|
|
///
|
|
/// let a: T = y;
|
|
///
|
|
/// The effect of this annotation is to relate the type `T_y` of the place `y`
|
|
/// to the user-given type `T`. The effect depends on the specified variance:
|
|
///
|
|
/// - `Covariant` -- requires that `T_y <: T`
|
|
/// - `Contravariant` -- requires that `T_y :> T`
|
|
/// - `Invariant` -- requires that `T_y == T`
|
|
/// - `Bivariant` -- no effect
|
|
///
|
|
/// When executed at runtime this is a nop.
|
|
///
|
|
/// Disallowed after drop elaboration.
|
|
AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
|
|
|
|
/// Marks the start of a "coverage region", injected with '-Cinstrument-coverage'. A
|
|
/// `Coverage` statement carries metadata about the coverage region, used to inject a coverage
|
|
/// map into the binary. If `Coverage::kind` is a `Counter`, the statement also generates
|
|
/// executable code, to increment a counter variable at runtime, each time the code region is
|
|
/// executed.
|
|
Coverage(Box<Coverage>),
|
|
|
|
/// Denotes a call to the intrinsic function `copy_nonoverlapping`.
|
|
///
|
|
/// First, all three operands are evaluated. `src` and `dest` must each be a reference, pointer,
|
|
/// or `Box` pointing to the same type `T`. `count` must evaluate to a `usize`. Then, `src` and
|
|
/// `dest` are dereferenced, and `count * size_of::<T>()` bytes beginning with the first byte of
|
|
/// the `src` place are copied to the continguous range of bytes beginning with the first byte
|
|
/// of `dest`.
|
|
///
|
|
/// **Needs clarification**: In what order are operands computed and dereferenced? It should
|
|
/// probably match the order for assignment, but that is also undecided.
|
|
///
|
|
/// **Needs clarification**: Is this typed or not, ie is there a typed load and store involved?
|
|
/// I vaguely remember Ralf saying somewhere that he thought it should not be.
|
|
CopyNonOverlapping(Box<CopyNonOverlapping<'tcx>>),
|
|
|
|
/// No-op. Useful for deleting instructions without affecting statement indices.
|
|
Nop,
|
|
}
|
|
|
|
impl<'tcx> StatementKind<'tcx> {
|
|
pub fn as_assign_mut(&mut self) -> Option<&mut (Place<'tcx>, Rvalue<'tcx>)> {
|
|
match self {
|
|
StatementKind::Assign(x) => Some(x),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub fn as_assign(&self) -> Option<&(Place<'tcx>, Rvalue<'tcx>)> {
|
|
match self {
|
|
StatementKind::Assign(x) => Some(x),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Describes what kind of retag is to be performed.
|
|
#[derive(Copy, Clone, TyEncodable, TyDecodable, Debug, PartialEq, Eq, Hash, HashStable)]
|
|
pub enum RetagKind {
|
|
/// The initial retag when entering a function.
|
|
FnEntry,
|
|
/// Retag preparing for a two-phase borrow.
|
|
TwoPhase,
|
|
/// Retagging raw pointers.
|
|
Raw,
|
|
/// A "normal" retag.
|
|
Default,
|
|
}
|
|
|
|
/// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
|
|
#[derive(Copy, Clone, TyEncodable, TyDecodable, Debug, Hash, HashStable, PartialEq)]
|
|
pub enum FakeReadCause {
|
|
/// Inject a fake read of the borrowed input at the end of each guards
|
|
/// code.
|
|
///
|
|
/// This should ensure that you cannot change the variant for an enum while
|
|
/// you are in the midst of matching on it.
|
|
ForMatchGuard,
|
|
|
|
/// `let x: !; match x {}` doesn't generate any read of x so we need to
|
|
/// generate a read of x to check that it is initialized and safe.
|
|
///
|
|
/// If a closure pattern matches a Place starting with an Upvar, then we introduce a
|
|
/// FakeRead for that Place outside the closure, in such a case this option would be
|
|
/// Some(closure_def_id).
|
|
/// Otherwise, the value of the optional DefId will be None.
|
|
ForMatchedPlace(Option<DefId>),
|
|
|
|
/// A fake read of the RefWithinGuard version of a bind-by-value variable
|
|
/// in a match guard to ensure that its value hasn't change by the time
|
|
/// we create the OutsideGuard version.
|
|
ForGuardBinding,
|
|
|
|
/// Officially, the semantics of
|
|
///
|
|
/// `let pattern = <expr>;`
|
|
///
|
|
/// is that `<expr>` is evaluated into a temporary and then this temporary is
|
|
/// into the pattern.
|
|
///
|
|
/// However, if we see the simple pattern `let var = <expr>`, we optimize this to
|
|
/// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
|
|
/// but in some cases it can affect the borrow checker, as in #53695.
|
|
/// Therefore, we insert a "fake read" here to ensure that we get
|
|
/// appropriate errors.
|
|
///
|
|
/// If a closure pattern matches a Place starting with an Upvar, then we introduce a
|
|
/// FakeRead for that Place outside the closure, in such a case this option would be
|
|
/// Some(closure_def_id).
|
|
/// Otherwise, the value of the optional DefId will be None.
|
|
ForLet(Option<DefId>),
|
|
|
|
/// If we have an index expression like
|
|
///
|
|
/// (*x)[1][{ x = y; 4}]
|
|
///
|
|
/// then the first bounds check is invalidated when we evaluate the second
|
|
/// index expression. Thus we create a fake borrow of `x` across the second
|
|
/// indexer, which will cause a borrow check error.
|
|
ForIndex,
|
|
}
|
|
|
|
impl Debug for Statement<'_> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
use self::StatementKind::*;
|
|
match self.kind {
|
|
Assign(box (ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
|
|
FakeRead(box (ref cause, ref place)) => {
|
|
write!(fmt, "FakeRead({:?}, {:?})", cause, place)
|
|
}
|
|
Retag(ref kind, ref place) => write!(
|
|
fmt,
|
|
"Retag({}{:?})",
|
|
match kind {
|
|
RetagKind::FnEntry => "[fn entry] ",
|
|
RetagKind::TwoPhase => "[2phase] ",
|
|
RetagKind::Raw => "[raw] ",
|
|
RetagKind::Default => "",
|
|
},
|
|
place,
|
|
),
|
|
StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
|
|
StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
|
|
SetDiscriminant { ref place, variant_index } => {
|
|
write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
|
|
}
|
|
Deinit(ref place) => write!(fmt, "Deinit({:?})", place),
|
|
AscribeUserType(box (ref place, ref c_ty), ref variance) => {
|
|
write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
|
|
}
|
|
Coverage(box self::Coverage { ref kind, code_region: Some(ref rgn) }) => {
|
|
write!(fmt, "Coverage::{:?} for {:?}", kind, rgn)
|
|
}
|
|
Coverage(box ref coverage) => write!(fmt, "Coverage::{:?}", coverage.kind),
|
|
CopyNonOverlapping(box crate::mir::CopyNonOverlapping {
|
|
ref src,
|
|
ref dst,
|
|
ref count,
|
|
}) => {
|
|
write!(fmt, "copy_nonoverlapping(src={:?}, dst={:?}, count={:?})", src, dst, count)
|
|
}
|
|
Nop => write!(fmt, "nop"),
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
|
|
pub struct Coverage {
|
|
pub kind: CoverageKind,
|
|
pub code_region: Option<CodeRegion>,
|
|
}
|
|
|
|
#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
|
|
pub struct CopyNonOverlapping<'tcx> {
|
|
pub src: Operand<'tcx>,
|
|
pub dst: Operand<'tcx>,
|
|
/// Number of elements to copy from src to dest, not bytes.
|
|
pub count: Operand<'tcx>,
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Places
|
|
|
|
/// Places roughly correspond to a "location in memory." Places in MIR are the same mathematical
|
|
/// object as places in Rust. This of course means that what exactly they are is undecided and part
|
|
/// of the Rust memory model. However, they will likely contain at least the following pieces of
|
|
/// information in some form:
|
|
///
|
|
/// 1. The address in memory that the place refers to.
|
|
/// 2. The provenance with which the place is being accessed.
|
|
/// 3. The type of the place and an optional variant index. See [`PlaceTy`][tcx::PlaceTy].
|
|
/// 4. Optionally, some metadata. This exists if and only if the type of the place is not `Sized`.
|
|
///
|
|
/// We'll give a description below of how all pieces of the place except for the provenance are
|
|
/// calculated. We cannot give a description of the provenance, because that is part of the
|
|
/// undecided aliasing model - we only include it here at all to acknowledge its existence.
|
|
///
|
|
/// Each local naturally corresponds to the place `Place { local, projection: [] }`. This place has
|
|
/// the address of the local's allocation and the type of the local.
|
|
///
|
|
/// **Needs clarification:** Unsized locals seem to present a bit of an issue. Their allocation
|
|
/// can't actually be created on `StorageLive`, because it's unclear how big to make the allocation.
|
|
/// Furthermore, MIR produces assignments to unsized locals, although that is not permitted under
|
|
/// `#![feature(unsized_locals)]` in Rust. Besides just putting "unsized locals are special and
|
|
/// different" in a bunch of places, I (JakobDegen) don't know how to incorporate this behavior into
|
|
/// the current MIR semantics in a clean way - possibly this needs some design work first.
|
|
///
|
|
/// For places that are not locals, ie they have a non-empty list of projections, we define the
|
|
/// values as a function of the parent place, that is the place with its last [`ProjectionElem`]
|
|
/// stripped. The way this is computed of course depends on the kind of that last projection
|
|
/// element:
|
|
///
|
|
/// - [`Downcast`](ProjectionElem::Downcast): This projection sets the place's variant index to the
|
|
/// given one, and makes no other changes. A `Downcast` projection on a place with its variant
|
|
/// index already set is not well-formed.
|
|
/// - [`Field`](ProjectionElem::Field): `Field` projections take their parent place and create a
|
|
/// place referring to one of the fields of the type. The resulting address is the parent
|
|
/// address, plus the offset of the field. The type becomes the type of the field. If the parent
|
|
/// was unsized and so had metadata associated with it, then the metadata is retained if the
|
|
/// field is unsized and thrown out if it is sized.
|
|
///
|
|
/// These projections are only legal for tuples, ADTs, closures, and generators. If the ADT or
|
|
/// generator has more than one variant, the parent place's variant index must be set, indicating
|
|
/// which variant is being used. If it has just one variant, the variant index may or may not be
|
|
/// included - the single possible variant is inferred if it is not included.
|
|
/// - [`ConstantIndex`](ProjectionElem::ConstantIndex): Computes an offset in units of `T` into the
|
|
/// place as described in the documentation for the `ProjectionElem`. The resulting address is
|
|
/// the parent's address plus that offset, and the type is `T`. This is only legal if the parent
|
|
/// place has type `[T; N]` or `[T]` (*not* `&[T]`). Since such a `T` is always sized, any
|
|
/// resulting metadata is thrown out.
|
|
/// - [`Subslice`](ProjectionElem::Subslice): This projection calculates an offset and a new
|
|
/// address in a similar manner as `ConstantIndex`. It is also only legal on `[T; N]` and `[T]`.
|
|
/// However, this yields a `Place` of type `[T]`, and additionally sets the metadata to be the
|
|
/// length of the subslice.
|
|
/// - [`Index`](ProjectionElem::Index): Like `ConstantIndex`, only legal on `[T; N]` or `[T]`.
|
|
/// However, `Index` additionally takes a local from which the value of the index is computed at
|
|
/// runtime. Computing the value of the index involves interpreting the `Local` as a
|
|
/// `Place { local, projection: [] }`, and then computing its value as if done via
|
|
/// [`Operand::Copy`]. The array/slice is then indexed with the resulting value. The local must
|
|
/// have type `usize`.
|
|
/// - [`Deref`](ProjectionElem::Deref): Derefs are the last type of projection, and the most
|
|
/// complicated. They are only legal on parent places that are references, pointers, or `Box`. A
|
|
/// `Deref` projection begins by loading a value from the parent place, as if by
|
|
/// [`Operand::Copy`]. It then dereferences the resulting pointer, creating a place of the
|
|
/// pointee's type. The resulting address is the address that was stored in the pointer. If the
|
|
/// pointee type is unsized, the pointer additionally stored the value of the metadata.
|
|
///
|
|
/// Computing a place may cause UB. One possibility is that the pointer used for a `Deref` may not
|
|
/// be suitably aligned. Another possibility is that the place is not in bounds, meaning it does not
|
|
/// point to an actual allocation.
|
|
///
|
|
/// However, if this is actually UB and when the UB kicks in is undecided. This is being discussed
|
|
/// in [UCG#319]. The options include that every place must obey those rules, that only some places
|
|
/// must obey them, or that places impose no rules of their own.
|
|
///
|
|
/// [UCG#319]: https://github.com/rust-lang/unsafe-code-guidelines/issues/319
|
|
///
|
|
/// Rust currently requires that every place obey those two rules. This is checked by MIRI and taken
|
|
/// advantage of by codegen (via `gep inbounds`). That is possibly subject to change.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, HashStable)]
|
|
pub struct Place<'tcx> {
|
|
pub local: Local,
|
|
|
|
/// projection out of a place (access a field, deref a pointer, etc)
|
|
pub projection: &'tcx List<PlaceElem<'tcx>>,
|
|
}
|
|
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(Place<'_>, 16);
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
#[derive(TyEncodable, TyDecodable, HashStable)]
|
|
pub enum ProjectionElem<V, T> {
|
|
Deref,
|
|
Field(Field, T),
|
|
/// Index into a slice/array.
|
|
///
|
|
/// Note that this does not also dereference, and so it does not exactly correspond to slice
|
|
/// indexing in Rust. In other words, in the below Rust code:
|
|
///
|
|
/// ```rust
|
|
/// let x = &[1, 2, 3, 4];
|
|
/// let i = 2;
|
|
/// x[i];
|
|
/// ```
|
|
///
|
|
/// The `x[i]` is turned into a `Deref` followed by an `Index`, not just an `Index`. The same
|
|
/// thing is true of the `ConstantIndex` and `Subslice` projections below.
|
|
Index(V),
|
|
|
|
/// These indices are generated by slice patterns. Easiest to explain
|
|
/// by example:
|
|
///
|
|
/// ```
|
|
/// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
|
|
/// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
|
|
/// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
|
|
/// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
|
|
/// ```
|
|
ConstantIndex {
|
|
/// index or -index (in Python terms), depending on from_end
|
|
offset: u64,
|
|
/// The thing being indexed must be at least this long. For arrays this
|
|
/// is always the exact length.
|
|
min_length: u64,
|
|
/// Counting backwards from end? This is always false when indexing an
|
|
/// array.
|
|
from_end: bool,
|
|
},
|
|
|
|
/// These indices are generated by slice patterns.
|
|
///
|
|
/// If `from_end` is true `slice[from..slice.len() - to]`.
|
|
/// Otherwise `array[from..to]`.
|
|
Subslice {
|
|
from: u64,
|
|
to: u64,
|
|
/// Whether `to` counts from the start or end of the array/slice.
|
|
/// For `PlaceElem`s this is `true` if and only if the base is a slice.
|
|
/// For `ProjectionKind`, this can also be `true` for arrays.
|
|
from_end: bool,
|
|
},
|
|
|
|
/// "Downcast" to a variant of an ADT. Currently, we only introduce
|
|
/// this for ADTs with more than one variant. It may be better to
|
|
/// just introduce it always, or always for enums.
|
|
///
|
|
/// The included Symbol is the name of the variant, used for printing MIR.
|
|
Downcast(Option<Symbol>, VariantIdx),
|
|
}
|
|
|
|
impl<V, T> ProjectionElem<V, T> {
|
|
/// Returns `true` if the target of this projection may refer to a different region of memory
|
|
/// than the base.
|
|
fn is_indirect(&self) -> bool {
|
|
match self {
|
|
Self::Deref => true,
|
|
|
|
Self::Field(_, _)
|
|
| Self::Index(_)
|
|
| Self::ConstantIndex { .. }
|
|
| Self::Subslice { .. }
|
|
| Self::Downcast(_, _) => false,
|
|
}
|
|
}
|
|
|
|
/// Returns `true` if this is a `Downcast` projection with the given `VariantIdx`.
|
|
pub fn is_downcast_to(&self, v: VariantIdx) -> bool {
|
|
matches!(*self, Self::Downcast(_, x) if x == v)
|
|
}
|
|
|
|
/// Returns `true` if this is a `Field` projection with the given index.
|
|
pub fn is_field_to(&self, f: Field) -> bool {
|
|
matches!(*self, Self::Field(x, _) if x == f)
|
|
}
|
|
}
|
|
|
|
/// Alias for projections as they appear in places, where the base is a place
|
|
/// and the index is a local.
|
|
pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
|
|
|
|
// This type is fairly frequently used, so we shouldn't unintentionally increase
|
|
// its size.
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(PlaceElem<'_>, 24);
|
|
|
|
/// Alias for projections as they appear in `UserTypeProjection`, where we
|
|
/// need neither the `V` parameter for `Index` nor the `T` for `Field`.
|
|
pub type ProjectionKind = ProjectionElem<(), ()>;
|
|
|
|
rustc_index::newtype_index! {
|
|
/// A [newtype'd][wrapper] index type in the MIR [control-flow graph][CFG]
|
|
///
|
|
/// A field (e.g., `f` in `_1.f`) is one variant of [`ProjectionElem`]. Conceptually,
|
|
/// rustc can identify that a field projection refers to either two different regions of memory
|
|
/// or the same one between the base and the 'projection element'.
|
|
/// Read more about projections in the [rustc-dev-guide][mir-datatypes]
|
|
///
|
|
/// [wrapper]: https://rustc-dev-guide.rust-lang.org/appendix/glossary.html#newtype
|
|
/// [CFG]: https://rustc-dev-guide.rust-lang.org/appendix/background.html#cfg
|
|
/// [mir-datatypes]: https://rustc-dev-guide.rust-lang.org/mir/index.html#mir-data-types
|
|
pub struct Field {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "field[{}]"
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
|
|
pub struct PlaceRef<'tcx> {
|
|
pub local: Local,
|
|
pub projection: &'tcx [PlaceElem<'tcx>],
|
|
}
|
|
|
|
impl<'tcx> Place<'tcx> {
|
|
// FIXME change this to a const fn by also making List::empty a const fn.
|
|
pub fn return_place() -> Place<'tcx> {
|
|
Place { local: RETURN_PLACE, projection: List::empty() }
|
|
}
|
|
|
|
/// Returns `true` if this `Place` contains a `Deref` projection.
|
|
///
|
|
/// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
|
|
/// same region of memory as its base.
|
|
pub fn is_indirect(&self) -> bool {
|
|
self.projection.iter().any(|elem| elem.is_indirect())
|
|
}
|
|
|
|
/// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
|
|
/// a single deref of a local.
|
|
#[inline(always)]
|
|
pub fn local_or_deref_local(&self) -> Option<Local> {
|
|
self.as_ref().local_or_deref_local()
|
|
}
|
|
|
|
/// If this place represents a local variable like `_X` with no
|
|
/// projections, return `Some(_X)`.
|
|
#[inline(always)]
|
|
pub fn as_local(&self) -> Option<Local> {
|
|
self.as_ref().as_local()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn as_ref(&self) -> PlaceRef<'tcx> {
|
|
PlaceRef { local: self.local, projection: &self.projection }
|
|
}
|
|
|
|
/// Iterate over the projections in evaluation order, i.e., the first element is the base with
|
|
/// its projection and then subsequently more projections are added.
|
|
/// As a concrete example, given the place a.b.c, this would yield:
|
|
/// - (a, .b)
|
|
/// - (a.b, .c)
|
|
///
|
|
/// Given a place without projections, the iterator is empty.
|
|
#[inline]
|
|
pub fn iter_projections(
|
|
self,
|
|
) -> impl Iterator<Item = (PlaceRef<'tcx>, PlaceElem<'tcx>)> + DoubleEndedIterator {
|
|
self.projection.iter().enumerate().map(move |(i, proj)| {
|
|
let base = PlaceRef { local: self.local, projection: &self.projection[..i] };
|
|
(base, proj)
|
|
})
|
|
}
|
|
|
|
/// Generates a new place by appending `more_projections` to the existing ones
|
|
/// and interning the result.
|
|
pub fn project_deeper(self, more_projections: &[PlaceElem<'tcx>], tcx: TyCtxt<'tcx>) -> Self {
|
|
if more_projections.is_empty() {
|
|
return self;
|
|
}
|
|
|
|
let mut v: Vec<PlaceElem<'tcx>>;
|
|
|
|
let new_projections = if self.projection.is_empty() {
|
|
more_projections
|
|
} else {
|
|
v = Vec::with_capacity(self.projection.len() + more_projections.len());
|
|
v.extend(self.projection);
|
|
v.extend(more_projections);
|
|
&v
|
|
};
|
|
|
|
Place { local: self.local, projection: tcx.intern_place_elems(new_projections) }
|
|
}
|
|
}
|
|
|
|
impl From<Local> for Place<'_> {
|
|
fn from(local: Local) -> Self {
|
|
Place { local, projection: List::empty() }
|
|
}
|
|
}
|
|
|
|
impl<'tcx> PlaceRef<'tcx> {
|
|
/// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
|
|
/// a single deref of a local.
|
|
pub fn local_or_deref_local(&self) -> Option<Local> {
|
|
match *self {
|
|
PlaceRef { local, projection: [] }
|
|
| PlaceRef { local, projection: [ProjectionElem::Deref] } => Some(local),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// If this place represents a local variable like `_X` with no
|
|
/// projections, return `Some(_X)`.
|
|
#[inline]
|
|
pub fn as_local(&self) -> Option<Local> {
|
|
match *self {
|
|
PlaceRef { local, projection: [] } => Some(local),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn last_projection(&self) -> Option<(PlaceRef<'tcx>, PlaceElem<'tcx>)> {
|
|
if let &[ref proj_base @ .., elem] = self.projection {
|
|
Some((PlaceRef { local: self.local, projection: proj_base }, elem))
|
|
} else {
|
|
None
|
|
}
|
|
}
|
|
}
|
|
|
|
impl Debug for Place<'_> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
for elem in self.projection.iter().rev() {
|
|
match elem {
|
|
ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
|
|
write!(fmt, "(").unwrap();
|
|
}
|
|
ProjectionElem::Deref => {
|
|
write!(fmt, "(*").unwrap();
|
|
}
|
|
ProjectionElem::Index(_)
|
|
| ProjectionElem::ConstantIndex { .. }
|
|
| ProjectionElem::Subslice { .. } => {}
|
|
}
|
|
}
|
|
|
|
write!(fmt, "{:?}", self.local)?;
|
|
|
|
for elem in self.projection.iter() {
|
|
match elem {
|
|
ProjectionElem::Downcast(Some(name), _index) => {
|
|
write!(fmt, " as {})", name)?;
|
|
}
|
|
ProjectionElem::Downcast(None, index) => {
|
|
write!(fmt, " as variant#{:?})", index)?;
|
|
}
|
|
ProjectionElem::Deref => {
|
|
write!(fmt, ")")?;
|
|
}
|
|
ProjectionElem::Field(field, ty) => {
|
|
write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
|
|
}
|
|
ProjectionElem::Index(ref index) => {
|
|
write!(fmt, "[{:?}]", index)?;
|
|
}
|
|
ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
|
|
write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
|
|
}
|
|
ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
|
|
write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
|
|
}
|
|
ProjectionElem::Subslice { from, to, from_end: true } if to == 0 => {
|
|
write!(fmt, "[{:?}:]", from)?;
|
|
}
|
|
ProjectionElem::Subslice { from, to, from_end: true } if from == 0 => {
|
|
write!(fmt, "[:-{:?}]", to)?;
|
|
}
|
|
ProjectionElem::Subslice { from, to, from_end: true } => {
|
|
write!(fmt, "[{:?}:-{:?}]", from, to)?;
|
|
}
|
|
ProjectionElem::Subslice { from, to, from_end: false } => {
|
|
write!(fmt, "[{:?}..{:?}]", from, to)?;
|
|
}
|
|
}
|
|
}
|
|
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Scopes
|
|
|
|
rustc_index::newtype_index! {
|
|
pub struct SourceScope {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "scope[{}]",
|
|
const OUTERMOST_SOURCE_SCOPE = 0,
|
|
}
|
|
}
|
|
|
|
impl SourceScope {
|
|
/// Finds the original HirId this MIR item came from.
|
|
/// This is necessary after MIR optimizations, as otherwise we get a HirId
|
|
/// from the function that was inlined instead of the function call site.
|
|
pub fn lint_root<'tcx>(
|
|
self,
|
|
source_scopes: &IndexVec<SourceScope, SourceScopeData<'tcx>>,
|
|
) -> Option<HirId> {
|
|
let mut data = &source_scopes[self];
|
|
// FIXME(oli-obk): we should be able to just walk the `inlined_parent_scope`, but it
|
|
// does not work as I thought it would. Needs more investigation and documentation.
|
|
while data.inlined.is_some() {
|
|
trace!(?data);
|
|
data = &source_scopes[data.parent_scope.unwrap()];
|
|
}
|
|
trace!(?data);
|
|
match &data.local_data {
|
|
ClearCrossCrate::Set(data) => Some(data.lint_root),
|
|
ClearCrossCrate::Clear => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct SourceScopeData<'tcx> {
|
|
pub span: Span,
|
|
pub parent_scope: Option<SourceScope>,
|
|
|
|
/// Whether this scope is the root of a scope tree of another body,
|
|
/// inlined into this body by the MIR inliner.
|
|
/// `ty::Instance` is the callee, and the `Span` is the call site.
|
|
pub inlined: Option<(ty::Instance<'tcx>, Span)>,
|
|
|
|
/// Nearest (transitive) parent scope (if any) which is inlined.
|
|
/// This is an optimization over walking up `parent_scope`
|
|
/// until a scope with `inlined: Some(...)` is found.
|
|
pub inlined_parent_scope: Option<SourceScope>,
|
|
|
|
/// Crate-local information for this source scope, that can't (and
|
|
/// needn't) be tracked across crates.
|
|
pub local_data: ClearCrossCrate<SourceScopeLocalData>,
|
|
}
|
|
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable)]
|
|
pub struct SourceScopeLocalData {
|
|
/// An `HirId` with lint levels equivalent to this scope's lint levels.
|
|
pub lint_root: hir::HirId,
|
|
/// The unsafe block that contains this node.
|
|
pub safety: Safety,
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
// Operands
|
|
|
|
/// An operand in MIR represents a "value" in Rust, the definition of which is undecided and part of
|
|
/// the memory model. One proposal for a definition of values can be found [on UCG][value-def].
|
|
///
|
|
/// [value-def]: https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/value-domain.md
|
|
///
|
|
/// The most common way to create values is via loading a place. Loading a place is an operation
|
|
/// which reads the memory of the place and converts it to a value. This is a fundamentally *typed*
|
|
/// operation. The nature of the value produced depends on the type of the conversion. Furthermore,
|
|
/// there may be other effects: if the type has a validity constraint loading the place might be UB
|
|
/// if the validity constraint is not met.
|
|
///
|
|
/// **Needs clarification:** Ralf proposes that loading a place not have side-effects.
|
|
/// This is what is implemented in miri today. Are these the semantics we want for MIR? Is this
|
|
/// something we can even decide without knowing more about Rust's memory model?
|
|
///
|
|
/// **Needs clarifiation:** Is loading a place that has its variant index set well-formed? Miri
|
|
/// currently implements it, but it seems like this may be something to check against in the
|
|
/// validator.
|
|
#[derive(Clone, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum Operand<'tcx> {
|
|
/// Creates a value by loading the given place. The type of the place must be `Copy`
|
|
Copy(Place<'tcx>),
|
|
|
|
/// Creates a value by performing loading the place, just like the `Copy` operand.
|
|
///
|
|
/// This *may* additionally overwrite the place with `uninit` bytes, depending on how we decide
|
|
/// in [UCG#188]. You should not emit MIR that may attempt a subsequent second load of this
|
|
/// place without first re-initializing it.
|
|
///
|
|
/// [UCG#188]: https://github.com/rust-lang/unsafe-code-guidelines/issues/188
|
|
Move(Place<'tcx>),
|
|
|
|
/// Constants are already semantically values, and remain unchanged.
|
|
Constant(Box<Constant<'tcx>>),
|
|
}
|
|
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(Operand<'_>, 24);
|
|
|
|
impl<'tcx> Debug for Operand<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
use self::Operand::*;
|
|
match *self {
|
|
Constant(ref a) => write!(fmt, "{:?}", a),
|
|
Copy(ref place) => write!(fmt, "{:?}", place),
|
|
Move(ref place) => write!(fmt, "move {:?}", place),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Operand<'tcx> {
|
|
/// Convenience helper to make a constant that refers to the fn
|
|
/// with given `DefId` and substs. Since this is used to synthesize
|
|
/// MIR, assumes `user_ty` is None.
|
|
pub fn function_handle(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: DefId,
|
|
substs: SubstsRef<'tcx>,
|
|
span: Span,
|
|
) -> Self {
|
|
let ty = tcx.type_of(def_id).subst(tcx, substs);
|
|
Operand::Constant(Box::new(Constant {
|
|
span,
|
|
user_ty: None,
|
|
literal: ConstantKind::Ty(ty::Const::zero_sized(tcx, ty)),
|
|
}))
|
|
}
|
|
|
|
pub fn is_move(&self) -> bool {
|
|
matches!(self, Operand::Move(..))
|
|
}
|
|
|
|
/// Convenience helper to make a literal-like constant from a given scalar value.
|
|
/// Since this is used to synthesize MIR, assumes `user_ty` is None.
|
|
pub fn const_from_scalar(
|
|
tcx: TyCtxt<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
val: Scalar,
|
|
span: Span,
|
|
) -> Operand<'tcx> {
|
|
debug_assert!({
|
|
let param_env_and_ty = ty::ParamEnv::empty().and(ty);
|
|
let type_size = tcx
|
|
.layout_of(param_env_and_ty)
|
|
.unwrap_or_else(|e| panic!("could not compute layout for {:?}: {:?}", ty, e))
|
|
.size;
|
|
let scalar_size = match val {
|
|
Scalar::Int(int) => int.size(),
|
|
_ => panic!("Invalid scalar type {:?}", val),
|
|
};
|
|
scalar_size == type_size
|
|
});
|
|
Operand::Constant(Box::new(Constant {
|
|
span,
|
|
user_ty: None,
|
|
literal: ConstantKind::Val(ConstValue::Scalar(val), ty),
|
|
}))
|
|
}
|
|
|
|
pub fn to_copy(&self) -> Self {
|
|
match *self {
|
|
Operand::Copy(_) | Operand::Constant(_) => self.clone(),
|
|
Operand::Move(place) => Operand::Copy(place),
|
|
}
|
|
}
|
|
|
|
/// Returns the `Place` that is the target of this `Operand`, or `None` if this `Operand` is a
|
|
/// constant.
|
|
pub fn place(&self) -> Option<Place<'tcx>> {
|
|
match self {
|
|
Operand::Copy(place) | Operand::Move(place) => Some(*place),
|
|
Operand::Constant(_) => None,
|
|
}
|
|
}
|
|
|
|
/// Returns the `Constant` that is the target of this `Operand`, or `None` if this `Operand` is a
|
|
/// place.
|
|
pub fn constant(&self) -> Option<&Constant<'tcx>> {
|
|
match self {
|
|
Operand::Constant(x) => Some(&**x),
|
|
Operand::Copy(_) | Operand::Move(_) => None,
|
|
}
|
|
}
|
|
|
|
/// Gets the `ty::FnDef` from an operand if it's a constant function item.
|
|
///
|
|
/// While this is unlikely in general, it's the normal case of what you'll
|
|
/// find as the `func` in a [`TerminatorKind::Call`].
|
|
pub fn const_fn_def(&self) -> Option<(DefId, SubstsRef<'tcx>)> {
|
|
let const_ty = self.constant()?.literal.ty();
|
|
if let ty::FnDef(def_id, substs) = *const_ty.kind() { Some((def_id, substs)) } else { None }
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// Rvalues
|
|
|
|
#[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq)]
|
|
/// The various kinds of rvalues that can appear in MIR.
|
|
///
|
|
/// Not all of these are allowed at every [`MirPhase`] - when this is the case, it's stated below.
|
|
///
|
|
/// Computing any rvalue begins by evaluating the places and operands in some order (**Needs
|
|
/// clarification**: Which order?). These are then used to produce a "value" - the same kind of
|
|
/// value that an [`Operand`] produces.
|
|
pub enum Rvalue<'tcx> {
|
|
/// Yields the operand unchanged
|
|
Use(Operand<'tcx>),
|
|
|
|
/// Creates an array where each element is the value of the operand.
|
|
///
|
|
/// This is the cause of a bug in the case where the repetition count is zero because the value
|
|
/// is not dropped, see [#74836].
|
|
///
|
|
/// Corresponds to source code like `[x; 32]`.
|
|
///
|
|
/// [#74836]: https://github.com/rust-lang/rust/issues/74836
|
|
Repeat(Operand<'tcx>, ty::Const<'tcx>),
|
|
|
|
/// Creates a reference of the indicated kind to the place.
|
|
///
|
|
/// There is not much to document here, because besides the obvious parts the semantics of this
|
|
/// are essentially entirely a part of the aliasing model. There are many UCG issues discussing
|
|
/// exactly what the behavior of this operation should be.
|
|
///
|
|
/// `Shallow` borrows are disallowed after drop lowering.
|
|
Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
|
|
|
|
/// Creates a pointer/reference to the given thread local.
|
|
///
|
|
/// The yielded type is a `*mut T` if the static is mutable, otherwise if the static is extern a
|
|
/// `*const T`, and if neither of those apply a `&T`.
|
|
///
|
|
/// **Note:** This is a runtime operation that actually executes code and is in this sense more
|
|
/// like a function call. Also, eliminating dead stores of this rvalue causes `fn main() {}` to
|
|
/// SIGILL for some reason that I (JakobDegen) never got a chance to look into.
|
|
///
|
|
/// **Needs clarification**: Are there weird additional semantics here related to the runtime
|
|
/// nature of this operation?
|
|
ThreadLocalRef(DefId),
|
|
|
|
/// Creates a pointer with the indicated mutability to the place.
|
|
///
|
|
/// This is generated by pointer casts like `&v as *const _` or raw address of expressions like
|
|
/// `&raw v` or `addr_of!(v)`.
|
|
///
|
|
/// Like with references, the semantics of this operation are heavily dependent on the aliasing
|
|
/// model.
|
|
AddressOf(Mutability, Place<'tcx>),
|
|
|
|
/// Yields the length of the place, as a `usize`.
|
|
///
|
|
/// If the type of the place is an array, this is the array length. For slices (`[T]`, not
|
|
/// `&[T]`) this accesses the place's metadata to determine the length. This rvalue is
|
|
/// ill-formed for places of other types.
|
|
Len(Place<'tcx>),
|
|
|
|
/// Performs essentially all of the casts that can be performed via `as`.
|
|
///
|
|
/// This allows for casts from/to a variety of types.
|
|
///
|
|
/// **FIXME**: Document exactly which `CastKind`s allow which types of casts. Figure out why
|
|
/// `ArrayToPointer` and `MutToConstPointer` are special.
|
|
Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
|
|
|
|
/// * `Offset` has the same semantics as [`offset`](pointer::offset), except that the second
|
|
/// parameter may be a `usize` as well.
|
|
/// * The comparison operations accept `bool`s, `char`s, signed or unsigned integers, floats,
|
|
/// raw pointers, or function pointers and return a `bool`. The types of the operands must be
|
|
/// matching, up to the usual caveat of the lifetimes in function pointers.
|
|
/// * Left and right shift operations accept signed or unsigned integers not necessarily of the
|
|
/// same type and return a value of the same type as their LHS. Like in Rust, the RHS is
|
|
/// truncated as needed.
|
|
/// * The `Bit*` operations accept signed integers, unsigned integers, or bools with matching
|
|
/// types and return a value of that type.
|
|
/// * The remaining operations accept signed integers, unsigned integers, or floats with
|
|
/// matching types and return a value of that type.
|
|
BinaryOp(BinOp, Box<(Operand<'tcx>, Operand<'tcx>)>),
|
|
|
|
/// Same as `BinaryOp`, but yields `(T, bool)` instead of `T`. In addition to performing the
|
|
/// same computation as the matching `BinaryOp`, checks if the infinite precison result would be
|
|
/// unequal to the actual result and sets the `bool` if this is the case.
|
|
///
|
|
/// This only supports addition, subtraction, multiplication, and shift operations on integers.
|
|
CheckedBinaryOp(BinOp, Box<(Operand<'tcx>, Operand<'tcx>)>),
|
|
|
|
/// Computes a value as described by the operation.
|
|
NullaryOp(NullOp, Ty<'tcx>),
|
|
|
|
/// Exactly like `BinaryOp`, but less operands.
|
|
///
|
|
/// Also does two's-complement arithmetic. Negation requires a signed integer or a float;
|
|
/// bitwise not requires a signed integer, unsigned integer, or bool. Both operation kinds
|
|
/// return a value with the same type as their operand.
|
|
UnaryOp(UnOp, Operand<'tcx>),
|
|
|
|
/// Computes the discriminant of the place, returning it as an integer of type
|
|
/// [`discriminant_ty`].
|
|
///
|
|
/// The validity requirements for the underlying value are undecided for this rvalue, see
|
|
/// [#91095]. Note too that the value of the discriminant is not the same thing as the
|
|
/// variant index; use [`discriminant_for_variant`] to convert.
|
|
///
|
|
/// For types defined in the source code as enums, this is well behaved. This is also well
|
|
/// formed for other types, but yields no particular value - there is no reason it couldn't be
|
|
/// defined to yield eg zero though.
|
|
///
|
|
/// [`discriminant_ty`]: crate::ty::Ty::discriminant_ty
|
|
/// [#91095]: https://github.com/rust-lang/rust/issues/91095
|
|
/// [`discriminant_for_variant`]: crate::ty::Ty::discriminant_for_variant
|
|
Discriminant(Place<'tcx>),
|
|
|
|
/// Creates an aggregate value, like a tuple or struct.
|
|
///
|
|
/// This is needed because dataflow analysis needs to distinguish
|
|
/// `dest = Foo { x: ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case that `Foo`
|
|
/// has a destructor.
|
|
///
|
|
/// Disallowed after deaggregation for all aggregate kinds except `Array` and `Generator`. After
|
|
/// generator lowering, `Generator` aggregate kinds are disallowed too.
|
|
Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
|
|
|
|
/// Transmutes a `*mut u8` into shallow-initialized `Box<T>`.
|
|
///
|
|
/// This is different from a normal transmute because dataflow analysis will treat the box as
|
|
/// initialized but its content as uninitialized. Like other pointer casts, this in general
|
|
/// affects alias analysis.
|
|
///
|
|
/// Disallowed after drop elaboration.
|
|
ShallowInitBox(Operand<'tcx>, Ty<'tcx>),
|
|
}
|
|
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(Rvalue<'_>, 40);
|
|
|
|
#[derive(Clone, Copy, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum CastKind {
|
|
Misc,
|
|
Pointer(PointerCast),
|
|
}
|
|
|
|
#[derive(Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum AggregateKind<'tcx> {
|
|
/// The type is of the element
|
|
Array(Ty<'tcx>),
|
|
Tuple,
|
|
|
|
/// The second field is the variant index. It's equal to 0 for struct
|
|
/// and union expressions. The fourth field is
|
|
/// active field number and is present only for union expressions
|
|
/// -- e.g., for a union expression `SomeUnion { c: .. }`, the
|
|
/// active field index would identity the field `c`
|
|
Adt(DefId, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
|
|
|
|
Closure(DefId, SubstsRef<'tcx>),
|
|
Generator(DefId, SubstsRef<'tcx>, hir::Movability),
|
|
}
|
|
|
|
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
|
|
static_assert_size!(AggregateKind<'_>, 48);
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, PartialOrd, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum BinOp {
|
|
/// The `+` operator (addition)
|
|
Add,
|
|
/// The `-` operator (subtraction)
|
|
Sub,
|
|
/// The `*` operator (multiplication)
|
|
Mul,
|
|
/// The `/` operator (division)
|
|
///
|
|
/// Division by zero is UB, because the compiler should have inserted checks
|
|
/// prior to this.
|
|
Div,
|
|
/// The `%` operator (modulus)
|
|
///
|
|
/// Using zero as the modulus (second operand) is UB, because the compiler
|
|
/// should have inserted checks prior to this.
|
|
Rem,
|
|
/// The `^` operator (bitwise xor)
|
|
BitXor,
|
|
/// The `&` operator (bitwise and)
|
|
BitAnd,
|
|
/// The `|` operator (bitwise or)
|
|
BitOr,
|
|
/// The `<<` operator (shift left)
|
|
///
|
|
/// The offset is truncated to the size of the first operand before shifting.
|
|
Shl,
|
|
/// The `>>` operator (shift right)
|
|
///
|
|
/// The offset is truncated to the size of the first operand before shifting.
|
|
Shr,
|
|
/// The `==` operator (equality)
|
|
Eq,
|
|
/// The `<` operator (less than)
|
|
Lt,
|
|
/// The `<=` operator (less than or equal to)
|
|
Le,
|
|
/// The `!=` operator (not equal to)
|
|
Ne,
|
|
/// The `>=` operator (greater than or equal to)
|
|
Ge,
|
|
/// The `>` operator (greater than)
|
|
Gt,
|
|
/// The `ptr.offset` operator
|
|
Offset,
|
|
}
|
|
|
|
impl BinOp {
|
|
pub fn is_checkable(self) -> bool {
|
|
use self::BinOp::*;
|
|
matches!(self, Add | Sub | Mul | Shl | Shr)
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum NullOp {
|
|
/// Returns the size of a value of that type
|
|
SizeOf,
|
|
/// Returns the minimum alignment of a type
|
|
AlignOf,
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub enum UnOp {
|
|
/// The `!` operator for logical inversion
|
|
Not,
|
|
/// The `-` operator for negation
|
|
Neg,
|
|
}
|
|
|
|
impl<'tcx> Debug for Rvalue<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
use self::Rvalue::*;
|
|
|
|
match *self {
|
|
Use(ref place) => write!(fmt, "{:?}", place),
|
|
Repeat(ref a, b) => {
|
|
write!(fmt, "[{:?}; ", a)?;
|
|
pretty_print_const(b, fmt, false)?;
|
|
write!(fmt, "]")
|
|
}
|
|
Len(ref a) => write!(fmt, "Len({:?})", a),
|
|
Cast(ref kind, ref place, ref ty) => {
|
|
write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
|
|
}
|
|
BinaryOp(ref op, box (ref a, ref b)) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
|
|
CheckedBinaryOp(ref op, box (ref a, ref b)) => {
|
|
write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
|
|
}
|
|
UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
|
|
Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
|
|
NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
|
|
ThreadLocalRef(did) => ty::tls::with(|tcx| {
|
|
let muta = tcx.static_mutability(did).unwrap().prefix_str();
|
|
write!(fmt, "&/*tls*/ {}{}", muta, tcx.def_path_str(did))
|
|
}),
|
|
Ref(region, borrow_kind, ref place) => {
|
|
let kind_str = match borrow_kind {
|
|
BorrowKind::Shared => "",
|
|
BorrowKind::Shallow => "shallow ",
|
|
BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
|
|
};
|
|
|
|
// When printing regions, add trailing space if necessary.
|
|
let print_region = ty::tls::with(|tcx| {
|
|
tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
|
|
});
|
|
let region = if print_region {
|
|
let mut region = region.to_string();
|
|
if !region.is_empty() {
|
|
region.push(' ');
|
|
}
|
|
region
|
|
} else {
|
|
// Do not even print 'static
|
|
String::new()
|
|
};
|
|
write!(fmt, "&{}{}{:?}", region, kind_str, place)
|
|
}
|
|
|
|
AddressOf(mutability, ref place) => {
|
|
let kind_str = match mutability {
|
|
Mutability::Mut => "mut",
|
|
Mutability::Not => "const",
|
|
};
|
|
|
|
write!(fmt, "&raw {} {:?}", kind_str, place)
|
|
}
|
|
|
|
Aggregate(ref kind, ref places) => {
|
|
let fmt_tuple = |fmt: &mut Formatter<'_>, name: &str| {
|
|
let mut tuple_fmt = fmt.debug_tuple(name);
|
|
for place in places {
|
|
tuple_fmt.field(place);
|
|
}
|
|
tuple_fmt.finish()
|
|
};
|
|
|
|
match **kind {
|
|
AggregateKind::Array(_) => write!(fmt, "{:?}", places),
|
|
|
|
AggregateKind::Tuple => {
|
|
if places.is_empty() {
|
|
write!(fmt, "()")
|
|
} else {
|
|
fmt_tuple(fmt, "")
|
|
}
|
|
}
|
|
|
|
AggregateKind::Adt(adt_did, variant, substs, _user_ty, _) => {
|
|
ty::tls::with(|tcx| {
|
|
let variant_def = &tcx.adt_def(adt_did).variant(variant);
|
|
let substs = tcx.lift(substs).expect("could not lift for printing");
|
|
let name = FmtPrinter::new(tcx, Namespace::ValueNS)
|
|
.print_def_path(variant_def.def_id, substs)?
|
|
.into_buffer();
|
|
|
|
match variant_def.ctor_kind {
|
|
CtorKind::Const => fmt.write_str(&name),
|
|
CtorKind::Fn => fmt_tuple(fmt, &name),
|
|
CtorKind::Fictive => {
|
|
let mut struct_fmt = fmt.debug_struct(&name);
|
|
for (field, place) in iter::zip(&variant_def.fields, places) {
|
|
struct_fmt.field(field.name.as_str(), place);
|
|
}
|
|
struct_fmt.finish()
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
AggregateKind::Closure(def_id, substs) => ty::tls::with(|tcx| {
|
|
if let Some(def_id) = def_id.as_local() {
|
|
let name = if tcx.sess.opts.debugging_opts.span_free_formats {
|
|
let substs = tcx.lift(substs).unwrap();
|
|
format!(
|
|
"[closure@{}]",
|
|
tcx.def_path_str_with_substs(def_id.to_def_id(), substs),
|
|
)
|
|
} else {
|
|
let span = tcx.def_span(def_id);
|
|
format!(
|
|
"[closure@{}]",
|
|
tcx.sess.source_map().span_to_diagnostic_string(span)
|
|
)
|
|
};
|
|
let mut struct_fmt = fmt.debug_struct(&name);
|
|
|
|
// FIXME(project-rfc-2229#48): This should be a list of capture names/places
|
|
if let Some(upvars) = tcx.upvars_mentioned(def_id) {
|
|
for (&var_id, place) in iter::zip(upvars.keys(), places) {
|
|
let var_name = tcx.hir().name(var_id);
|
|
struct_fmt.field(var_name.as_str(), place);
|
|
}
|
|
}
|
|
|
|
struct_fmt.finish()
|
|
} else {
|
|
write!(fmt, "[closure]")
|
|
}
|
|
}),
|
|
|
|
AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
|
|
if let Some(def_id) = def_id.as_local() {
|
|
let name = format!("[generator@{:?}]", tcx.def_span(def_id));
|
|
let mut struct_fmt = fmt.debug_struct(&name);
|
|
|
|
// FIXME(project-rfc-2229#48): This should be a list of capture names/places
|
|
if let Some(upvars) = tcx.upvars_mentioned(def_id) {
|
|
for (&var_id, place) in iter::zip(upvars.keys(), places) {
|
|
let var_name = tcx.hir().name(var_id);
|
|
struct_fmt.field(var_name.as_str(), place);
|
|
}
|
|
}
|
|
|
|
struct_fmt.finish()
|
|
} else {
|
|
write!(fmt, "[generator]")
|
|
}
|
|
}),
|
|
}
|
|
}
|
|
|
|
ShallowInitBox(ref place, ref ty) => {
|
|
write!(fmt, "ShallowInitBox({:?}, {:?})", place, ty)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
///////////////////////////////////////////////////////////////////////////
|
|
/// Constants
|
|
///
|
|
/// Two constants are equal if they are the same constant. Note that
|
|
/// this does not necessarily mean that they are `==` in Rust. In
|
|
/// particular, one must be wary of `NaN`!
|
|
|
|
#[derive(Clone, Copy, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)]
|
|
pub struct Constant<'tcx> {
|
|
pub span: Span,
|
|
|
|
/// Optional user-given type: for something like
|
|
/// `collect::<Vec<_>>`, this would be present and would
|
|
/// indicate that `Vec<_>` was explicitly specified.
|
|
///
|
|
/// Needed for NLL to impose user-given type constraints.
|
|
pub user_ty: Option<UserTypeAnnotationIndex>,
|
|
|
|
pub literal: ConstantKind<'tcx>,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable, Debug)]
|
|
#[derive(Lift)]
|
|
pub enum ConstantKind<'tcx> {
|
|
/// This constant came from the type system
|
|
Ty(ty::Const<'tcx>),
|
|
/// This constant cannot go back into the type system, as it represents
|
|
/// something the type system cannot handle (e.g. pointers).
|
|
Val(interpret::ConstValue<'tcx>, Ty<'tcx>),
|
|
}
|
|
|
|
impl<'tcx> Constant<'tcx> {
|
|
pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
|
|
match self.literal.try_to_scalar() {
|
|
Some(Scalar::Ptr(ptr, _size)) => match tcx.global_alloc(ptr.provenance) {
|
|
GlobalAlloc::Static(def_id) => {
|
|
assert!(!tcx.is_thread_local_static(def_id));
|
|
Some(def_id)
|
|
}
|
|
_ => None,
|
|
},
|
|
_ => None,
|
|
}
|
|
}
|
|
#[inline]
|
|
pub fn ty(&self) -> Ty<'tcx> {
|
|
self.literal.ty()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> From<ty::Const<'tcx>> for ConstantKind<'tcx> {
|
|
#[inline]
|
|
fn from(ct: ty::Const<'tcx>) -> Self {
|
|
match ct.val() {
|
|
ty::ConstKind::Value(cv) => {
|
|
// FIXME Once valtrees are introduced we need to convert those
|
|
// into `ConstValue` instances here
|
|
Self::Val(cv, ct.ty())
|
|
}
|
|
_ => Self::Ty(ct),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> ConstantKind<'tcx> {
|
|
/// Returns `None` if the constant is not trivially safe for use in the type system.
|
|
pub fn const_for_ty(&self) -> Option<ty::Const<'tcx>> {
|
|
match self {
|
|
ConstantKind::Ty(c) => Some(*c),
|
|
ConstantKind::Val(..) => None,
|
|
}
|
|
}
|
|
|
|
pub fn ty(&self) -> Ty<'tcx> {
|
|
match self {
|
|
ConstantKind::Ty(c) => c.ty(),
|
|
ConstantKind::Val(_, ty) => *ty,
|
|
}
|
|
}
|
|
|
|
pub fn try_val(&self) -> Option<ConstValue<'tcx>> {
|
|
match self {
|
|
ConstantKind::Ty(c) => match c.val() {
|
|
ty::ConstKind::Value(v) => Some(v),
|
|
_ => None,
|
|
},
|
|
ConstantKind::Val(v, _) => Some(*v),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_to_value(self) -> Option<interpret::ConstValue<'tcx>> {
|
|
match self {
|
|
ConstantKind::Ty(c) => c.val().try_to_value(),
|
|
ConstantKind::Val(val, _) => Some(val),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_to_scalar(self) -> Option<Scalar> {
|
|
self.try_to_value()?.try_to_scalar()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_to_scalar_int(self) -> Option<ScalarInt> {
|
|
Some(self.try_to_value()?.try_to_scalar()?.assert_int())
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_to_bits(self, size: Size) -> Option<u128> {
|
|
self.try_to_scalar_int()?.to_bits(size).ok()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_to_bool(self) -> Option<bool> {
|
|
self.try_to_scalar_int()?.try_into().ok()
|
|
}
|
|
|
|
#[inline]
|
|
pub fn eval(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Self {
|
|
match self {
|
|
Self::Ty(c) => {
|
|
// FIXME Need to use a different evaluation function that directly returns a `ConstValue`
|
|
// if evaluation succeeds and does not create a ValTree first
|
|
if let Some(val) = c.val().try_eval(tcx, param_env) {
|
|
match val {
|
|
Ok(val) => Self::Val(val, c.ty()),
|
|
Err(_) => Self::Ty(tcx.const_error(self.ty())),
|
|
}
|
|
} else {
|
|
self
|
|
}
|
|
}
|
|
Self::Val(_, _) => self,
|
|
}
|
|
}
|
|
|
|
/// Panics if the value cannot be evaluated or doesn't contain a valid integer of the given type.
|
|
#[inline]
|
|
pub fn eval_bits(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> u128 {
|
|
self.try_eval_bits(tcx, param_env, ty)
|
|
.unwrap_or_else(|| bug!("expected bits of {:#?}, got {:#?}", ty, self))
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_eval_bits(
|
|
&self,
|
|
tcx: TyCtxt<'tcx>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> Option<u128> {
|
|
match self {
|
|
Self::Ty(ct) => ct.try_eval_bits(tcx, param_env, ty),
|
|
Self::Val(val, t) => {
|
|
assert_eq!(*t, ty);
|
|
let size =
|
|
tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size;
|
|
val.try_to_bits(size)
|
|
}
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_eval_bool(&self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Option<bool> {
|
|
match self {
|
|
Self::Ty(ct) => ct.try_eval_bool(tcx, param_env),
|
|
Self::Val(val, _) => val.try_to_bool(),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn try_eval_usize(&self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Option<u64> {
|
|
match self {
|
|
Self::Ty(ct) => ct.try_eval_usize(tcx, param_env),
|
|
Self::Val(val, _) => val.try_to_machine_usize(tcx),
|
|
}
|
|
}
|
|
|
|
pub fn from_bits(
|
|
tcx: TyCtxt<'tcx>,
|
|
bits: u128,
|
|
param_env_ty: ty::ParamEnvAnd<'tcx, Ty<'tcx>>,
|
|
) -> Self {
|
|
let size = tcx
|
|
.layout_of(param_env_ty)
|
|
.unwrap_or_else(|e| {
|
|
bug!("could not compute layout for {:?}: {:?}", param_env_ty.value, e)
|
|
})
|
|
.size;
|
|
let cv = ConstValue::Scalar(Scalar::from_uint(bits, size));
|
|
|
|
Self::Val(cv, param_env_ty.value)
|
|
}
|
|
|
|
pub fn from_bool(tcx: TyCtxt<'tcx>, v: bool) -> Self {
|
|
let cv = ConstValue::from_bool(v);
|
|
Self::Val(cv, tcx.types.bool)
|
|
}
|
|
|
|
pub fn zero_sized(ty: Ty<'tcx>) -> Self {
|
|
let cv = ConstValue::Scalar(Scalar::ZST);
|
|
Self::Val(cv, ty)
|
|
}
|
|
|
|
pub fn from_usize(tcx: TyCtxt<'tcx>, n: u64) -> Self {
|
|
let ty = tcx.types.usize;
|
|
Self::from_bits(tcx, n as u128, ty::ParamEnv::empty().and(ty))
|
|
}
|
|
|
|
/// Literals are converted to `ConstantKindVal`, const generic parameters are eagerly
|
|
/// converted to a constant, everything else becomes `Unevaluated`.
|
|
pub fn from_anon_const(
|
|
tcx: TyCtxt<'tcx>,
|
|
def_id: LocalDefId,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
) -> Self {
|
|
Self::from_opt_const_arg_anon_const(tcx, ty::WithOptConstParam::unknown(def_id), param_env)
|
|
}
|
|
|
|
#[instrument(skip(tcx), level = "debug")]
|
|
fn from_opt_const_arg_anon_const(
|
|
tcx: TyCtxt<'tcx>,
|
|
def: ty::WithOptConstParam<LocalDefId>,
|
|
param_env: ty::ParamEnv<'tcx>,
|
|
) -> Self {
|
|
let body_id = match tcx.hir().get_by_def_id(def.did) {
|
|
hir::Node::AnonConst(ac) => ac.body,
|
|
_ => span_bug!(
|
|
tcx.def_span(def.did.to_def_id()),
|
|
"from_anon_const can only process anonymous constants"
|
|
),
|
|
};
|
|
|
|
let expr = &tcx.hir().body(body_id).value;
|
|
debug!(?expr);
|
|
|
|
// Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments
|
|
// currently have to be wrapped in curly brackets, so it's necessary to special-case.
|
|
let expr = match &expr.kind {
|
|
hir::ExprKind::Block(block, _) if block.stmts.is_empty() && block.expr.is_some() => {
|
|
block.expr.as_ref().unwrap()
|
|
}
|
|
_ => expr,
|
|
};
|
|
|
|
let ty = tcx.type_of(def.def_id_for_type_of());
|
|
|
|
// FIXME(const_generics): We currently have to special case parameters because `min_const_generics`
|
|
// does not provide the parents generics to anonymous constants. We still allow generic const
|
|
// parameters by themselves however, e.g. `N`. These constants would cause an ICE if we were to
|
|
// ever try to substitute the generic parameters in their bodies.
|
|
//
|
|
// While this doesn't happen as these constants are always used as `ty::ConstKind::Param`, it does
|
|
// cause issues if we were to remove that special-case and try to evaluate the constant instead.
|
|
use hir::{def::DefKind::ConstParam, def::Res, ExprKind, Path, QPath};
|
|
match expr.kind {
|
|
ExprKind::Path(QPath::Resolved(_, &Path { res: Res::Def(ConstParam, def_id), .. })) => {
|
|
// Find the name and index of the const parameter by indexing the generics of
|
|
// the parent item and construct a `ParamConst`.
|
|
let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
|
|
let item_id = tcx.hir().get_parent_node(hir_id);
|
|
let item_def_id = tcx.hir().local_def_id(item_id);
|
|
let generics = tcx.generics_of(item_def_id.to_def_id());
|
|
let index = generics.param_def_id_to_index[&def_id];
|
|
let name = tcx.hir().name(hir_id);
|
|
let ty_const = tcx.mk_const(ty::ConstS {
|
|
val: ty::ConstKind::Param(ty::ParamConst::new(index, name)),
|
|
ty,
|
|
});
|
|
|
|
return Self::Ty(ty_const);
|
|
}
|
|
_ => {}
|
|
}
|
|
|
|
let hir_id = tcx.hir().local_def_id_to_hir_id(def.did);
|
|
let parent_substs = if let Some(parent_hir_id) = tcx.hir().find_parent_node(hir_id) {
|
|
if let Some(parent_did) = tcx.hir().opt_local_def_id(parent_hir_id) {
|
|
InternalSubsts::identity_for_item(tcx, parent_did.to_def_id())
|
|
} else {
|
|
tcx.mk_substs(Vec::<GenericArg<'tcx>>::new().into_iter())
|
|
}
|
|
} else {
|
|
tcx.mk_substs(Vec::<GenericArg<'tcx>>::new().into_iter())
|
|
};
|
|
debug!(?parent_substs);
|
|
|
|
let did = def.did.to_def_id();
|
|
let child_substs = InternalSubsts::identity_for_item(tcx, did);
|
|
let substs = tcx.mk_substs(parent_substs.into_iter().chain(child_substs.into_iter()));
|
|
debug!(?substs);
|
|
|
|
let hir_id = tcx.hir().local_def_id_to_hir_id(def.did);
|
|
let span = tcx.hir().span(hir_id);
|
|
let uneval = ty::Unevaluated::new(def.to_global(), substs);
|
|
debug!(?span, ?param_env);
|
|
|
|
match tcx.const_eval_resolve(param_env, uneval, Some(span)) {
|
|
Ok(val) => Self::Val(val, ty),
|
|
Err(_) => {
|
|
// Error was handled in `const_eval_resolve`. Here we just create a
|
|
// new unevaluated const and error hard later in codegen
|
|
let ty_const = tcx.mk_const(ty::ConstS {
|
|
val: ty::ConstKind::Unevaluated(ty::Unevaluated {
|
|
def: def.to_global(),
|
|
substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
|
|
promoted: None,
|
|
}),
|
|
ty,
|
|
});
|
|
|
|
Self::Ty(ty_const)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A collection of projections into user types.
|
|
///
|
|
/// They are projections because a binding can occur a part of a
|
|
/// parent pattern that has been ascribed a type.
|
|
///
|
|
/// Its a collection because there can be multiple type ascriptions on
|
|
/// the path from the root of the pattern down to the binding itself.
|
|
///
|
|
/// An example:
|
|
///
|
|
/// ```rust
|
|
/// struct S<'a>((i32, &'a str), String);
|
|
/// let S((_, w): (i32, &'static str), _): S = ...;
|
|
/// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
|
|
/// // --------------------------------- ^ (2)
|
|
/// ```
|
|
///
|
|
/// The highlights labelled `(1)` show the subpattern `(_, w)` being
|
|
/// ascribed the type `(i32, &'static str)`.
|
|
///
|
|
/// The highlights labelled `(2)` show the whole pattern being
|
|
/// ascribed the type `S`.
|
|
///
|
|
/// In this example, when we descend to `w`, we will have built up the
|
|
/// following two projected types:
|
|
///
|
|
/// * base: `S`, projection: `(base.0).1`
|
|
/// * base: `(i32, &'static str)`, projection: `base.1`
|
|
///
|
|
/// The first will lead to the constraint `w: &'1 str` (for some
|
|
/// inferred region `'1`). The second will lead to the constraint `w:
|
|
/// &'static str`.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
|
|
pub struct UserTypeProjections {
|
|
pub contents: Vec<(UserTypeProjection, Span)>,
|
|
}
|
|
|
|
impl<'tcx> UserTypeProjections {
|
|
pub fn none() -> Self {
|
|
UserTypeProjections { contents: vec![] }
|
|
}
|
|
|
|
pub fn is_empty(&self) -> bool {
|
|
self.contents.is_empty()
|
|
}
|
|
|
|
pub fn projections_and_spans(
|
|
&self,
|
|
) -> impl Iterator<Item = &(UserTypeProjection, Span)> + ExactSizeIterator {
|
|
self.contents.iter()
|
|
}
|
|
|
|
pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> + ExactSizeIterator {
|
|
self.contents.iter().map(|&(ref user_type, _span)| user_type)
|
|
}
|
|
|
|
pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
|
|
self.contents.push((user_ty.clone(), span));
|
|
self
|
|
}
|
|
|
|
fn map_projections(
|
|
mut self,
|
|
mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
|
|
) -> Self {
|
|
self.contents = self.contents.into_iter().map(|(proj, span)| (f(proj), span)).collect();
|
|
self
|
|
}
|
|
|
|
pub fn index(self) -> Self {
|
|
self.map_projections(|pat_ty_proj| pat_ty_proj.index())
|
|
}
|
|
|
|
pub fn subslice(self, from: u64, to: u64) -> Self {
|
|
self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
|
|
}
|
|
|
|
pub fn deref(self) -> Self {
|
|
self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
|
|
}
|
|
|
|
pub fn leaf(self, field: Field) -> Self {
|
|
self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
|
|
}
|
|
|
|
pub fn variant(self, adt_def: AdtDef<'tcx>, variant_index: VariantIdx, field: Field) -> Self {
|
|
self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
|
|
}
|
|
}
|
|
|
|
/// Encodes the effect of a user-supplied type annotation on the
|
|
/// subcomponents of a pattern. The effect is determined by applying the
|
|
/// given list of projections to some underlying base type. Often,
|
|
/// the projection element list `projs` is empty, in which case this
|
|
/// directly encodes a type in `base`. But in the case of complex patterns with
|
|
/// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
|
|
/// in which case the `projs` vector is used.
|
|
///
|
|
/// Examples:
|
|
///
|
|
/// * `let x: T = ...` -- here, the `projs` vector is empty.
|
|
///
|
|
/// * `let (x, _): T = ...` -- here, the `projs` vector would contain
|
|
/// `field[0]` (aka `.0`), indicating that the type of `s` is
|
|
/// determined by finding the type of the `.0` field from `T`.
|
|
#[derive(Clone, Debug, TyEncodable, TyDecodable, Hash, HashStable, PartialEq)]
|
|
pub struct UserTypeProjection {
|
|
pub base: UserTypeAnnotationIndex,
|
|
pub projs: Vec<ProjectionKind>,
|
|
}
|
|
|
|
impl Copy for ProjectionKind {}
|
|
|
|
impl UserTypeProjection {
|
|
pub(crate) fn index(mut self) -> Self {
|
|
self.projs.push(ProjectionElem::Index(()));
|
|
self
|
|
}
|
|
|
|
pub(crate) fn subslice(mut self, from: u64, to: u64) -> Self {
|
|
self.projs.push(ProjectionElem::Subslice { from, to, from_end: true });
|
|
self
|
|
}
|
|
|
|
pub(crate) fn deref(mut self) -> Self {
|
|
self.projs.push(ProjectionElem::Deref);
|
|
self
|
|
}
|
|
|
|
pub(crate) fn leaf(mut self, field: Field) -> Self {
|
|
self.projs.push(ProjectionElem::Field(field, ()));
|
|
self
|
|
}
|
|
|
|
pub(crate) fn variant(
|
|
mut self,
|
|
adt_def: AdtDef<'_>,
|
|
variant_index: VariantIdx,
|
|
field: Field,
|
|
) -> Self {
|
|
self.projs.push(ProjectionElem::Downcast(
|
|
Some(adt_def.variant(variant_index).name),
|
|
variant_index,
|
|
));
|
|
self.projs.push(ProjectionElem::Field(field, ()));
|
|
self
|
|
}
|
|
}
|
|
|
|
TrivialTypeFoldableAndLiftImpls! { ProjectionKind, }
|
|
|
|
impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
|
|
fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
|
|
self,
|
|
folder: &mut F,
|
|
) -> Result<Self, F::Error> {
|
|
Ok(UserTypeProjection {
|
|
base: self.base.try_fold_with(folder)?,
|
|
projs: self.projs.try_fold_with(folder)?,
|
|
})
|
|
}
|
|
|
|
fn super_visit_with<Vs: TypeVisitor<'tcx>>(
|
|
&self,
|
|
visitor: &mut Vs,
|
|
) -> ControlFlow<Vs::BreakTy> {
|
|
self.base.visit_with(visitor)
|
|
// Note: there's nothing in `self.proj` to visit.
|
|
}
|
|
}
|
|
|
|
rustc_index::newtype_index! {
|
|
pub struct Promoted {
|
|
derive [HashStable]
|
|
DEBUG_FORMAT = "promoted[{}]"
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Debug for Constant<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
write!(fmt, "{}", self)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Display for Constant<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
match self.ty().kind() {
|
|
ty::FnDef(..) => {}
|
|
_ => write!(fmt, "const ")?,
|
|
}
|
|
Display::fmt(&self.literal, fmt)
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Display for ConstantKind<'tcx> {
|
|
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
|
match *self {
|
|
ConstantKind::Ty(c) => pretty_print_const(c, fmt, true),
|
|
ConstantKind::Val(val, ty) => pretty_print_const_value(val, ty, fmt, true),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn pretty_print_const<'tcx>(
|
|
c: ty::Const<'tcx>,
|
|
fmt: &mut Formatter<'_>,
|
|
print_types: bool,
|
|
) -> fmt::Result {
|
|
use crate::ty::print::PrettyPrinter;
|
|
ty::tls::with(|tcx| {
|
|
let literal = tcx.lift(c).unwrap();
|
|
let mut cx = FmtPrinter::new(tcx, Namespace::ValueNS);
|
|
cx.print_alloc_ids = true;
|
|
let cx = cx.pretty_print_const(literal, print_types)?;
|
|
fmt.write_str(&cx.into_buffer())?;
|
|
Ok(())
|
|
})
|
|
}
|
|
|
|
fn pretty_print_const_value<'tcx>(
|
|
val: interpret::ConstValue<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
fmt: &mut Formatter<'_>,
|
|
print_types: bool,
|
|
) -> fmt::Result {
|
|
use crate::ty::print::PrettyPrinter;
|
|
ty::tls::with(|tcx| {
|
|
let val = tcx.lift(val).unwrap();
|
|
let ty = tcx.lift(ty).unwrap();
|
|
let mut cx = FmtPrinter::new(tcx, Namespace::ValueNS);
|
|
cx.print_alloc_ids = true;
|
|
let cx = cx.pretty_print_const_value(val, ty, print_types)?;
|
|
fmt.write_str(&cx.into_buffer())?;
|
|
Ok(())
|
|
})
|
|
}
|
|
|
|
impl<'tcx> graph::DirectedGraph for Body<'tcx> {
|
|
type Node = BasicBlock;
|
|
}
|
|
|
|
impl<'tcx> graph::WithNumNodes for Body<'tcx> {
|
|
#[inline]
|
|
fn num_nodes(&self) -> usize {
|
|
self.basic_blocks.len()
|
|
}
|
|
}
|
|
|
|
impl<'tcx> graph::WithStartNode for Body<'tcx> {
|
|
#[inline]
|
|
fn start_node(&self) -> Self::Node {
|
|
START_BLOCK
|
|
}
|
|
}
|
|
|
|
impl<'tcx> graph::WithSuccessors for Body<'tcx> {
|
|
#[inline]
|
|
fn successors(&self, node: Self::Node) -> <Self as GraphSuccessors<'_>>::Iter {
|
|
self.basic_blocks[node].terminator().successors().cloned()
|
|
}
|
|
}
|
|
|
|
impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
|
|
type Item = BasicBlock;
|
|
type Iter = iter::Cloned<Successors<'b>>;
|
|
}
|
|
|
|
impl<'tcx, 'graph> graph::GraphPredecessors<'graph> for Body<'tcx> {
|
|
type Item = BasicBlock;
|
|
type Iter = std::iter::Copied<std::slice::Iter<'graph, BasicBlock>>;
|
|
}
|
|
|
|
impl<'tcx> graph::WithPredecessors for Body<'tcx> {
|
|
#[inline]
|
|
fn predecessors(&self, node: Self::Node) -> <Self as graph::GraphPredecessors<'_>>::Iter {
|
|
self.predecessors()[node].iter().copied()
|
|
}
|
|
}
|
|
|
|
/// `Location` represents the position of the start of the statement; or, if
|
|
/// `statement_index` equals the number of statements, then the start of the
|
|
/// terminator.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
|
|
pub struct Location {
|
|
/// The block that the location is within.
|
|
pub block: BasicBlock,
|
|
|
|
pub statement_index: usize,
|
|
}
|
|
|
|
impl fmt::Debug for Location {
|
|
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
|
write!(fmt, "{:?}[{}]", self.block, self.statement_index)
|
|
}
|
|
}
|
|
|
|
impl Location {
|
|
pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
|
|
|
|
/// Returns the location immediately after this one within the enclosing block.
|
|
///
|
|
/// Note that if this location represents a terminator, then the
|
|
/// resulting location would be out of bounds and invalid.
|
|
pub fn successor_within_block(&self) -> Location {
|
|
Location { block: self.block, statement_index: self.statement_index + 1 }
|
|
}
|
|
|
|
/// Returns `true` if `other` is earlier in the control flow graph than `self`.
|
|
pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
|
|
// If we are in the same block as the other location and are an earlier statement
|
|
// then we are a predecessor of `other`.
|
|
if self.block == other.block && self.statement_index < other.statement_index {
|
|
return true;
|
|
}
|
|
|
|
let predecessors = body.predecessors();
|
|
|
|
// If we're in another block, then we want to check that block is a predecessor of `other`.
|
|
let mut queue: Vec<BasicBlock> = predecessors[other.block].to_vec();
|
|
let mut visited = FxHashSet::default();
|
|
|
|
while let Some(block) = queue.pop() {
|
|
// If we haven't visited this block before, then make sure we visit its predecessors.
|
|
if visited.insert(block) {
|
|
queue.extend(predecessors[block].iter().cloned());
|
|
} else {
|
|
continue;
|
|
}
|
|
|
|
// If we found the block that `self` is in, then we are a predecessor of `other` (since
|
|
// we found that block by looking at the predecessors of `other`).
|
|
if self.block == block {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
false
|
|
}
|
|
|
|
pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
|
|
if self.block == other.block {
|
|
self.statement_index <= other.statement_index
|
|
} else {
|
|
dominators.is_dominated_by(other.block, self.block)
|
|
}
|
|
}
|
|
}
|