1 // ignore-tidy-filelength
3 //! MIR datatypes and passes. See the [rustc guide] for more info.
5 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
7 use crate::hir::def::{CtorKind, Namespace};
8 use crate::hir::def_id::DefId;
9 use crate::hir::{self, GeneratorKind};
10 use crate::mir::interpret::{GlobalAlloc, PanicInfo, Scalar};
11 use crate::mir::visit::MirVisitable;
12 use crate::ty::adjustment::PointerCast;
13 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
14 use crate::ty::layout::VariantIdx;
15 use crate::ty::print::{FmtPrinter, Printer};
16 use crate::ty::subst::{Subst, SubstsRef};
18 self, AdtDef, CanonicalUserTypeAnnotations, List, Region, Ty, TyCtxt, UserTypeAnnotationIndex,
21 use polonius_engine::Atom;
22 use rustc_index::bit_set::BitMatrix;
23 use rustc_data_structures::fx::FxHashSet;
24 use rustc_data_structures::graph::dominators::Dominators;
25 use rustc_data_structures::graph::{self, GraphSuccessors};
26 use rustc_index::vec::{Idx, IndexVec};
27 use rustc_data_structures::sync::Lrc;
28 use rustc_macros::HashStable;
29 use rustc_serialize::{Encodable, Decodable};
30 use smallvec::SmallVec;
32 use std::fmt::{self, Debug, Display, Formatter, Write};
35 use std::{iter, mem, option, u32};
36 use syntax::ast::Name;
37 use syntax::symbol::Symbol;
38 use syntax_pos::{Span, DUMMY_SP};
40 pub use crate::mir::interpret::AssertMessage;
41 // FIXME(nashenas88) Cache only exported for use in librustc_mir/transform/check_unsafety.rs
42 pub use crate::mir::cache::{BodyCache, Cache, ReadOnlyBodyCache};
43 pub use crate::read_only;
53 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
55 pub trait HasLocalDecls<'tcx> {
56 fn local_decls(&self) -> &LocalDecls<'tcx>;
59 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
60 fn local_decls(&self) -> &LocalDecls<'tcx> {
65 impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
66 fn local_decls(&self) -> &LocalDecls<'tcx> {
71 /// The various "big phases" that MIR goes through.
73 /// Warning: ordering of variants is significant.
74 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, HashStable,
75 Debug, PartialEq, Eq, PartialOrd, Ord)]
84 /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
85 pub fn phase_index(&self) -> usize {
90 /// The lowered representation of a single function.
91 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable, TypeFoldable)]
92 pub struct Body<'tcx> {
93 /// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
94 /// that indexes into this vector.
95 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
97 /// Records how far through the "desugaring and optimization" process this particular
98 /// MIR has traversed. This is particularly useful when inlining, since in that context
99 /// we instantiate the promoted constants and add them to our promoted vector -- but those
100 /// promoted items have already been optimized, whereas ours have not. This field allows
101 /// us to see the difference and forego optimization on the inlined promoted items.
104 /// A list of source scopes; these are referenced by statements
105 /// and used for debuginfo. Indexed by a `SourceScope`.
106 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
108 /// The yield type of the function, if it is a generator.
109 pub yield_ty: Option<Ty<'tcx>>,
111 /// Generator drop glue.
112 pub generator_drop: Option<Box<BodyCache<'tcx>>>,
114 /// The layout of a generator. Produced by the state transformation.
115 pub generator_layout: Option<GeneratorLayout<'tcx>>,
117 /// If this is a generator then record the type of source expression that caused this generator
119 pub generator_kind: Option<GeneratorKind>,
121 /// Declarations of locals.
123 /// The first local is the return value pointer, followed by `arg_count`
124 /// locals for the function arguments, followed by any user-declared
125 /// variables and temporaries.
126 pub local_decls: LocalDecls<'tcx>,
128 /// User type annotations.
129 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
131 /// The number of arguments this function takes.
133 /// Starting at local 1, `arg_count` locals will be provided by the caller
134 /// and can be assumed to be initialized.
136 /// If this MIR was built for a constant, this will be 0.
137 pub arg_count: usize,
139 /// Mark an argument local (which must be a tuple) as getting passed as
140 /// its individual components at the LLVM level.
142 /// This is used for the "rust-call" ABI.
143 pub spread_arg: Option<Local>,
145 /// Debug information pertaining to user variables, including captures.
146 pub var_debug_info: Vec<VarDebugInfo<'tcx>>,
148 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
149 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
150 /// this conversion from happening and use short circuiting, we will cause the following code
151 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
153 /// List of places where control flow was destroyed. Used for error reporting.
154 pub control_flow_destroyed: Vec<(Span, String)>,
156 /// A span representing this MIR, for error reporting.
160 impl<'tcx> Body<'tcx> {
162 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
163 source_scopes: IndexVec<SourceScope, SourceScopeData>,
164 local_decls: LocalDecls<'tcx>,
165 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
167 var_debug_info: Vec<VarDebugInfo<'tcx>>,
169 control_flow_destroyed: Vec<(Span, String)>,
170 generator_kind : Option<GeneratorKind>,
172 // We need `arg_count` locals, and one for the return place.
174 local_decls.len() >= arg_count + 1,
175 "expected at least {} locals, got {}",
181 phase: MirPhase::Build,
185 generator_drop: None,
186 generator_layout: None,
189 user_type_annotations,
194 control_flow_destroyed,
199 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
203 /// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
205 pub fn is_cfg_cyclic(&self) -> bool {
206 graph::is_cyclic(self)
210 pub fn local_kind(&self, local: Local) -> LocalKind {
211 let index = local.as_usize();
214 self.local_decls[local].mutability == Mutability::Mut,
215 "return place should be mutable"
218 LocalKind::ReturnPointer
219 } else if index < self.arg_count + 1 {
221 } else if self.local_decls[local].is_user_variable() {
228 /// Returns an iterator over all temporaries.
230 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
231 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
232 let local = Local::new(index);
233 if self.local_decls[local].is_user_variable() {
241 /// Returns an iterator over all user-declared locals.
243 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
244 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
245 let local = Local::new(index);
246 if self.local_decls[local].is_user_variable() {
254 /// Returns an iterator over all user-declared mutable locals.
256 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
257 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
258 let local = Local::new(index);
259 let decl = &self.local_decls[local];
260 if decl.is_user_variable() && decl.mutability == Mutability::Mut {
268 /// Returns an iterator over all user-declared mutable arguments and locals.
270 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
271 (1..self.local_decls.len()).filter_map(move |index| {
272 let local = Local::new(index);
273 let decl = &self.local_decls[local];
274 if (decl.is_user_variable() || index < self.arg_count + 1)
275 && decl.mutability == Mutability::Mut
284 /// Returns an iterator over all function arguments.
286 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
287 let arg_count = self.arg_count;
288 (1..=arg_count).map(Local::new)
291 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
292 /// locals that are neither arguments nor the return place).
294 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
295 let arg_count = self.arg_count;
296 let local_count = self.local_decls.len();
297 (arg_count + 1..local_count).map(Local::new)
300 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
301 /// invalidating statement indices in `Location`s.
302 pub fn make_statement_nop(&mut self, location: Location) {
303 let block = &mut self.basic_blocks[location.block];
304 debug_assert!(location.statement_index < block.statements.len());
305 block.statements[location.statement_index].make_nop()
308 /// Returns the source info associated with `location`.
309 pub fn source_info(&self, location: Location) -> &SourceInfo {
310 let block = &self[location.block];
311 let stmts = &block.statements;
312 let idx = location.statement_index;
313 if idx < stmts.len() {
314 &stmts[idx].source_info
316 assert_eq!(idx, stmts.len());
317 &block.terminator().source_info
321 /// Checks if `sub` is a sub scope of `sup`
322 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
324 match self.source_scopes[sub].parent_scope {
325 None => return false,
332 /// Returns the return type; it always return first element from `local_decls` array.
333 pub fn return_ty(&self) -> Ty<'tcx> {
334 self.local_decls[RETURN_PLACE].ty
337 /// Gets the location of the terminator for the given block.
338 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
339 Location { block: bb, statement_index: self[bb].statements.len() }
343 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
346 /// Unsafe because of a PushUnsafeBlock
348 /// Unsafe because of an unsafe fn
350 /// Unsafe because of an `unsafe` block
351 ExplicitUnsafe(hir::HirId),
354 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
355 type Output = BasicBlockData<'tcx>;
358 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
359 &self.basic_blocks()[index]
363 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
364 pub enum ClearCrossCrate<T> {
369 impl<T> ClearCrossCrate<T> {
370 pub fn as_ref(&'a self) -> ClearCrossCrate<&'a T> {
372 ClearCrossCrate::Clear => ClearCrossCrate::Clear,
373 ClearCrossCrate::Set(v) => ClearCrossCrate::Set(v),
377 pub fn assert_crate_local(self) -> T {
379 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
380 ClearCrossCrate::Set(v) => v,
385 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
386 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
388 /// Grouped information about the source code origin of a MIR entity.
389 /// Intended to be inspected by diagnostics and debuginfo.
390 /// Most passes can work with it as a whole, within a single function.
391 // The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
392 // `Hash`. Please ping @bjorn3 if removing them.
393 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
394 pub struct SourceInfo {
395 /// The source span for the AST pertaining to this MIR entity.
398 /// The source scope, keeping track of which bindings can be
399 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
400 pub scope: SourceScope,
403 ///////////////////////////////////////////////////////////////////////////
404 // Mutability and borrow kinds
406 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
407 pub enum Mutability {
412 impl From<Mutability> for hir::Mutability {
413 fn from(m: Mutability) -> Self {
415 Mutability::Mut => hir::Mutability::Mutable,
416 Mutability::Not => hir::Mutability::Immutable,
422 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
424 pub enum BorrowKind {
425 /// Data must be immutable and is aliasable.
428 /// The immediately borrowed place must be immutable, but projections from
429 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
430 /// conflict with a mutable borrow of `a.b.c`.
432 /// This is used when lowering matches: when matching on a place we want to
433 /// ensure that place have the same value from the start of the match until
434 /// an arm is selected. This prevents this code from compiling:
436 /// let mut x = &Some(0);
439 /// Some(_) if { x = &None; false } => (),
443 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
444 /// should not prevent `if let None = x { ... }`, for example, because the
445 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
446 /// We can also report errors with this kind of borrow differently.
449 /// Data must be immutable but not aliasable. This kind of borrow
450 /// cannot currently be expressed by the user and is used only in
451 /// implicit closure bindings. It is needed when the closure is
452 /// borrowing or mutating a mutable referent, e.g.:
454 /// let x: &mut isize = ...;
455 /// let y = || *x += 5;
457 /// If we were to try to translate this closure into a more explicit
458 /// form, we'd encounter an error with the code as written:
460 /// struct Env { x: & &mut isize }
461 /// let x: &mut isize = ...;
462 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
463 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
465 /// This is then illegal because you cannot mutate an `&mut` found
466 /// in an aliasable location. To solve, you'd have to translate with
467 /// an `&mut` borrow:
469 /// struct Env { x: & &mut isize }
470 /// let x: &mut isize = ...;
471 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
472 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
474 /// Now the assignment to `**env.x` is legal, but creating a
475 /// mutable pointer to `x` is not because `x` is not mutable. We
476 /// could fix this by declaring `x` as `let mut x`. This is ok in
477 /// user code, if awkward, but extra weird for closures, since the
478 /// borrow is hidden.
480 /// So we introduce a "unique imm" borrow -- the referent is
481 /// immutable, but not aliasable. This solves the problem. For
482 /// simplicity, we don't give users the way to express this
483 /// borrow, it's just used when translating closures.
486 /// Data is mutable and not aliasable.
488 /// `true` if this borrow arose from method-call auto-ref
489 /// (i.e., `adjustment::Adjust::Borrow`).
490 allow_two_phase_borrow: bool,
495 pub fn allows_two_phase_borrow(&self) -> bool {
497 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
498 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
503 ///////////////////////////////////////////////////////////////////////////
504 // Variables and temps
506 rustc_index::newtype_index! {
509 DEBUG_FORMAT = "_{}",
510 const RETURN_PLACE = 0,
514 impl Atom for Local {
515 fn index(self) -> usize {
520 /// Classifies locals into categories. See `Body::local_kind`.
521 #[derive(PartialEq, Eq, Debug, HashStable)]
523 /// User-declared variable binding.
525 /// Compiler-introduced temporary.
527 /// Function argument.
529 /// Location of function's return value.
533 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
534 pub struct VarBindingForm<'tcx> {
535 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
536 pub binding_mode: ty::BindingMode,
537 /// If an explicit type was provided for this variable binding,
538 /// this holds the source Span of that type.
540 /// NOTE: if you want to change this to a `HirId`, be wary that
541 /// doing so breaks incremental compilation (as of this writing),
542 /// while a `Span` does not cause our tests to fail.
543 pub opt_ty_info: Option<Span>,
544 /// Place of the RHS of the =, or the subject of the `match` where this
545 /// variable is initialized. None in the case of `let PATTERN;`.
546 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
547 /// (a) the right-hand side isn't evaluated as a place expression.
548 /// (b) it gives a way to separate this case from the remaining cases
550 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
551 /// The span of the pattern in which this variable was bound.
555 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
556 pub enum BindingForm<'tcx> {
557 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
558 Var(VarBindingForm<'tcx>),
559 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
560 ImplicitSelf(ImplicitSelfKind),
561 /// Reference used in a guard expression to ensure immutability.
565 /// Represents what type of implicit self a function has, if any.
566 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
567 pub enum ImplicitSelfKind {
568 /// Represents a `fn x(self);`.
570 /// Represents a `fn x(mut self);`.
572 /// Represents a `fn x(&self);`.
574 /// Represents a `fn x(&mut self);`.
576 /// Represents when a function does not have a self argument or
577 /// when a function has a `self: X` argument.
581 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
583 mod binding_form_impl {
584 use crate::ich::StableHashingContext;
585 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
587 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
588 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
589 use super::BindingForm::*;
590 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
593 Var(binding) => binding.hash_stable(hcx, hasher),
594 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
601 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
602 /// created during evaluation of expressions in a block tail
603 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
605 /// It is used to improve diagnostics when such temporaries are
606 /// involved in borrow_check errors, e.g., explanations of where the
607 /// temporaries come from, when their destructors are run, and/or how
608 /// one might revise the code to satisfy the borrow checker's rules.
609 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
610 pub struct BlockTailInfo {
611 /// If `true`, then the value resulting from evaluating this tail
612 /// expression is ignored by the block's expression context.
614 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
615 /// but not e.g., `let _x = { ...; tail };`
616 pub tail_result_is_ignored: bool,
621 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
622 /// argument, or the return place.
623 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
624 pub struct LocalDecl<'tcx> {
625 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
627 /// Temporaries and the return place are always mutable.
628 pub mutability: Mutability,
630 // FIXME(matthewjasper) Don't store in this in `Body`
631 pub local_info: LocalInfo<'tcx>,
633 /// `true` if this is an internal local.
635 /// These locals are not based on types in the source code and are only used
636 /// for a few desugarings at the moment.
638 /// The generator transformation will sanity check the locals which are live
639 /// across a suspension point against the type components of the generator
640 /// which type checking knows are live across a suspension point. We need to
641 /// flag drop flags to avoid triggering this check as they are introduced
644 /// Unsafety checking will also ignore dereferences of these locals,
645 /// so they can be used for raw pointers only used in a desugaring.
647 /// This should be sound because the drop flags are fully algebraic, and
648 /// therefore don't affect the OIBIT or outlives properties of the
652 /// If this local is a temporary and `is_block_tail` is `Some`,
653 /// then it is a temporary created for evaluation of some
654 /// subexpression of some block's tail expression (with no
655 /// intervening statement context).
656 // FIXME(matthewjasper) Don't store in this in `Body`
657 pub is_block_tail: Option<BlockTailInfo>,
659 /// The type of this local.
662 /// If the user manually ascribed a type to this variable,
663 /// e.g., via `let x: T`, then we carry that type here. The MIR
664 /// borrow checker needs this information since it can affect
665 /// region inference.
666 // FIXME(matthewjasper) Don't store in this in `Body`
667 pub user_ty: UserTypeProjections,
669 /// The *syntactic* (i.e., not visibility) source scope the local is defined
670 /// in. If the local was defined in a let-statement, this
671 /// is *within* the let-statement, rather than outside
674 /// This is needed because the visibility source scope of locals within
675 /// a let-statement is weird.
677 /// The reason is that we want the local to be *within* the let-statement
678 /// for lint purposes, but we want the local to be *after* the let-statement
679 /// for names-in-scope purposes.
681 /// That's it, if we have a let-statement like the one in this
685 /// fn foo(x: &str) {
686 /// #[allow(unused_mut)]
687 /// let mut x: u32 = { // <- one unused mut
688 /// let mut y: u32 = x.parse().unwrap();
695 /// Then, from a lint point of view, the declaration of `x: u32`
696 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
697 /// lint scopes are the same as the AST/HIR nesting.
699 /// However, from a name lookup point of view, the scopes look more like
700 /// as if the let-statements were `match` expressions:
703 /// fn foo(x: &str) {
705 /// match x.parse().unwrap() {
714 /// We care about the name-lookup scopes for debuginfo - if the
715 /// debuginfo instruction pointer is at the call to `x.parse()`, we
716 /// want `x` to refer to `x: &str`, but if it is at the call to
717 /// `drop(x)`, we want it to refer to `x: u32`.
719 /// To allow both uses to work, we need to have more than a single scope
720 /// for a local. We have the `source_info.scope` represent the "syntactic"
721 /// lint scope (with a variable being under its let block) while the
722 /// `var_debug_info.source_info.scope` represents the "local variable"
723 /// scope (where the "rest" of a block is under all prior let-statements).
725 /// The end result looks like this:
729 /// │{ argument x: &str }
731 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
732 /// │ │ // in practice because I'm lazy.
734 /// │ │← x.source_info.scope
735 /// │ │← `x.parse().unwrap()`
737 /// │ │ │← y.source_info.scope
739 /// │ │ │{ let y: u32 }
741 /// │ │ │← y.var_debug_info.source_info.scope
744 /// │ │{ let x: u32 }
745 /// │ │← x.var_debug_info.source_info.scope
746 /// │ │← `drop(x)` // This accesses `x: u32`.
748 pub source_info: SourceInfo,
751 /// Extra information about a local that's used for diagnostics.
752 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
753 pub enum LocalInfo<'tcx> {
754 /// A user-defined local variable or function parameter
756 /// The `BindingForm` is solely used for local diagnostics when generating
757 /// warnings/errors when compiling the current crate, and therefore it need
758 /// not be visible across crates.
759 User(ClearCrossCrate<BindingForm<'tcx>>),
760 /// A temporary created that references the static with the given `DefId`.
761 StaticRef { def_id: DefId, is_thread_local: bool },
762 /// Any other temporary, the return place, or an anonymous function parameter.
766 impl<'tcx> LocalDecl<'tcx> {
767 /// Returns `true` only if local is a binding that can itself be
768 /// made mutable via the addition of the `mut` keyword, namely
769 /// something like the occurrences of `x` in:
770 /// - `fn foo(x: Type) { ... }`,
772 /// - or `match ... { C(x) => ... }`
773 pub fn can_be_made_mutable(&self) -> bool {
774 match self.local_info {
775 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
776 binding_mode: ty::BindingMode::BindByValue(_),
783 ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)),
790 /// Returns `true` if local is definitely not a `ref ident` or
791 /// `ref mut ident` binding. (Such bindings cannot be made into
792 /// mutable bindings, but the inverse does not necessarily hold).
793 pub fn is_nonref_binding(&self) -> bool {
794 match self.local_info {
795 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
796 binding_mode: ty::BindingMode::BindByValue(_),
802 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
808 /// Returns `true` if this variable is a named variable or function
809 /// parameter declared by the user.
811 pub fn is_user_variable(&self) -> bool {
812 match self.local_info {
813 LocalInfo::User(_) => true,
818 /// Returns `true` if this is a reference to a variable bound in a `match`
819 /// expression that is used to access said variable for the guard of the
821 pub fn is_ref_for_guard(&self) -> bool {
822 match self.local_info {
823 LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
828 /// Returns `Some` if this is a reference to a static item that is used to
829 /// access that static
830 pub fn is_ref_to_static(&self) -> bool {
831 match self.local_info {
832 LocalInfo::StaticRef { .. } => true,
837 /// Returns `Some` if this is a reference to a static item that is used to
838 /// access that static
839 pub fn is_ref_to_thread_local(&self) -> bool {
840 match self.local_info {
841 LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
846 /// Returns `true` is the local is from a compiler desugaring, e.g.,
847 /// `__next` from a `for` loop.
849 pub fn from_compiler_desugaring(&self) -> bool {
850 self.source_info.span.desugaring_kind().is_some()
853 /// Creates a new `LocalDecl` for a temporary.
855 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
856 Self::new_local(ty, Mutability::Mut, false, span)
859 /// Converts `self` into same `LocalDecl` except tagged as immutable.
861 pub fn immutable(mut self) -> Self {
862 self.mutability = Mutability::Not;
866 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
868 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
869 assert!(self.is_block_tail.is_none());
870 self.is_block_tail = Some(info);
874 /// Creates a new `LocalDecl` for a internal temporary.
876 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
877 Self::new_local(ty, Mutability::Mut, true, span)
881 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
885 user_ty: UserTypeProjections::none(),
886 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
888 local_info: LocalInfo::Other,
893 /// Builds a `LocalDecl` for the return place.
895 /// This must be inserted into the `local_decls` list as the first local.
897 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
899 mutability: Mutability::Mut,
901 user_ty: UserTypeProjections::none(),
902 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
905 local_info: LocalInfo::Other,
910 /// Debug information pertaining to a user variable.
911 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
912 pub struct VarDebugInfo<'tcx> {
915 /// Source info of the user variable, including the scope
916 /// within which the variable is visible (to debuginfo)
917 /// (see `LocalDecl`'s `source_info` field for more details).
918 pub source_info: SourceInfo,
920 /// Where the data for this user variable is to be found.
921 /// NOTE(eddyb) There's an unenforced invariant that this `Place` is
922 /// based on a `Local`, not a `Static`, and contains no indexing.
923 pub place: Place<'tcx>,
926 ///////////////////////////////////////////////////////////////////////////
929 rustc_index::newtype_index! {
930 pub struct BasicBlock {
932 DEBUG_FORMAT = "bb{}",
933 const START_BLOCK = 0,
938 pub fn start_location(self) -> Location {
939 Location { block: self, statement_index: 0 }
943 ///////////////////////////////////////////////////////////////////////////
944 // BasicBlockData and Terminator
946 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
947 pub struct BasicBlockData<'tcx> {
948 /// List of statements in this block.
949 pub statements: Vec<Statement<'tcx>>,
951 /// Terminator for this block.
953 /// N.B., this should generally ONLY be `None` during construction.
954 /// Therefore, you should generally access it via the
955 /// `terminator()` or `terminator_mut()` methods. The only
956 /// exception is that certain passes, such as `simplify_cfg`, swap
957 /// out the terminator temporarily with `None` while they continue
958 /// to recurse over the set of basic blocks.
959 pub terminator: Option<Terminator<'tcx>>,
961 /// If true, this block lies on an unwind path. This is used
962 /// during codegen where distinct kinds of basic blocks may be
963 /// generated (particularly for MSVC cleanup). Unwind blocks must
964 /// only branch to other unwind blocks.
965 pub is_cleanup: bool,
968 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
969 pub struct Terminator<'tcx> {
970 pub source_info: SourceInfo,
971 pub kind: TerminatorKind<'tcx>,
974 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
975 pub enum TerminatorKind<'tcx> {
976 /// Block should have one successor in the graph; we jump there.
977 Goto { target: BasicBlock },
979 /// Operand evaluates to an integer; jump depending on its value
980 /// to one of the targets, and otherwise fallback to `otherwise`.
982 /// The discriminant value being tested.
983 discr: Operand<'tcx>,
985 /// The type of value being tested.
988 /// Possible values. The locations to branch to in each case
989 /// are found in the corresponding indices from the `targets` vector.
990 values: Cow<'tcx, [u128]>,
992 /// Possible branch sites. The last element of this vector is used
993 /// for the otherwise branch, so targets.len() == values.len() + 1
996 // This invariant is quite non-obvious and also could be improved.
997 // One way to make this invariant is to have something like this instead:
999 // branches: Vec<(ConstInt, BasicBlock)>,
1000 // otherwise: Option<BasicBlock> // exhaustive if None
1002 // However we’ve decided to keep this as-is until we figure a case
1003 // where some other approach seems to be strictly better than other.
1004 targets: Vec<BasicBlock>,
1007 /// Indicates that the landing pad is finished and unwinding should
1008 /// continue. Emitted by `build::scope::diverge_cleanup`.
1011 /// Indicates that the landing pad is finished and that the process
1012 /// should abort. Used to prevent unwinding for foreign items.
1015 /// Indicates a normal return. The return place should have
1016 /// been filled in by now. This should occur at most once.
1019 /// Indicates a terminator that can never be reached.
1022 /// Drop the `Place`.
1023 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1025 /// Drop the `Place` and assign the new value over it. This ensures
1026 /// that the assignment to `P` occurs *even if* the destructor for
1027 /// place unwinds. Its semantics are best explained by the
1032 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1040 /// Drop(P, goto BB1, unwind BB2)
1043 /// // P is now uninitialized
1047 /// // P is now uninitialized -- its dtor panicked
1052 location: Place<'tcx>,
1053 value: Operand<'tcx>,
1055 unwind: Option<BasicBlock>,
1058 /// Block ends with a call of a converging function.
1060 /// The function that’s being called.
1061 func: Operand<'tcx>,
1062 /// Arguments the function is called with.
1063 /// These are owned by the callee, which is free to modify them.
1064 /// This allows the memory occupied by "by-value" arguments to be
1065 /// reused across function calls without duplicating the contents.
1066 args: Vec<Operand<'tcx>>,
1067 /// Destination for the return value. If some, the call is converging.
1068 destination: Option<(Place<'tcx>, BasicBlock)>,
1069 /// Cleanups to be done if the call unwinds.
1070 cleanup: Option<BasicBlock>,
1071 /// `true` if this is from a call in HIR rather than from an overloaded
1072 /// operator. True for overloaded function call.
1073 from_hir_call: bool,
1076 /// Jump to the target if the condition has the expected value,
1077 /// otherwise panic with a message and a cleanup target.
1079 cond: Operand<'tcx>,
1081 msg: AssertMessage<'tcx>,
1083 cleanup: Option<BasicBlock>,
1086 /// A suspend point.
1088 /// The value to return.
1089 value: Operand<'tcx>,
1090 /// Where to resume to.
1092 /// Cleanup to be done if the generator is dropped at this suspend point.
1093 drop: Option<BasicBlock>,
1096 /// Indicates the end of the dropping of a generator.
1099 /// A block where control flow only ever takes one real path, but borrowck
1100 /// needs to be more conservative.
1102 /// The target normal control flow will take.
1103 real_target: BasicBlock,
1104 /// A block control flow could conceptually jump to, but won't in
1106 imaginary_target: BasicBlock,
1108 /// A terminator for blocks that only take one path in reality, but where we
1109 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1110 /// This can arise in infinite loops with no function calls for example.
1112 /// The target normal control flow will take.
1113 real_target: BasicBlock,
1114 /// The imaginary cleanup block link. This particular path will never be taken
1115 /// in practice, but in order to avoid fragility we want to always
1116 /// consider it in borrowck. We don't want to accept programs which
1117 /// pass borrowck only when `panic=abort` or some assertions are disabled
1118 /// due to release vs. debug mode builds. This needs to be an `Option` because
1119 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1120 unwind: Option<BasicBlock>,
1124 pub type Successors<'a> =
1125 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1126 pub type SuccessorsMut<'a> =
1127 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1129 impl<'tcx> Terminator<'tcx> {
1130 pub fn successors(&self) -> Successors<'_> {
1131 self.kind.successors()
1134 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1135 self.kind.successors_mut()
1138 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1142 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1143 self.kind.unwind_mut()
1147 impl<'tcx> TerminatorKind<'tcx> {
1150 cond: Operand<'tcx>,
1153 ) -> TerminatorKind<'tcx> {
1154 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1155 TerminatorKind::SwitchInt {
1157 switch_ty: tcx.types.bool,
1158 values: From::from(BOOL_SWITCH_FALSE),
1159 targets: vec![f, t],
1163 pub fn successors(&self) -> Successors<'_> {
1164 use self::TerminatorKind::*;
1171 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1172 Goto { target: ref t }
1173 | Call { destination: None, cleanup: Some(ref t), .. }
1174 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1175 | Yield { resume: ref t, drop: None, .. }
1176 | DropAndReplace { target: ref t, unwind: None, .. }
1177 | Drop { target: ref t, unwind: None, .. }
1178 | Assert { target: ref t, cleanup: None, .. }
1179 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1180 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1181 | Yield { resume: ref t, drop: Some(ref u), .. }
1182 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1183 | Drop { target: ref t, unwind: Some(ref u), .. }
1184 | Assert { target: ref t, cleanup: Some(ref u), .. }
1185 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1186 Some(t).into_iter().chain(slice::from_ref(u))
1188 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1189 FalseEdges { ref real_target, ref imaginary_target } => {
1190 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1195 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1196 use self::TerminatorKind::*;
1203 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1204 Goto { target: ref mut t }
1205 | Call { destination: None, cleanup: Some(ref mut t), .. }
1206 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1207 | Yield { resume: ref mut t, drop: None, .. }
1208 | DropAndReplace { target: ref mut t, unwind: None, .. }
1209 | Drop { target: ref mut t, unwind: None, .. }
1210 | Assert { target: ref mut t, cleanup: None, .. }
1211 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1212 Some(t).into_iter().chain(&mut [])
1214 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1215 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1216 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1217 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1218 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1219 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1220 Some(t).into_iter().chain(slice::from_mut(u))
1222 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1223 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1224 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1229 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1231 TerminatorKind::Goto { .. }
1232 | TerminatorKind::Resume
1233 | TerminatorKind::Abort
1234 | TerminatorKind::Return
1235 | TerminatorKind::Unreachable
1236 | TerminatorKind::GeneratorDrop
1237 | TerminatorKind::Yield { .. }
1238 | TerminatorKind::SwitchInt { .. }
1239 | TerminatorKind::FalseEdges { .. } => None,
1240 TerminatorKind::Call { cleanup: ref unwind, .. }
1241 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1242 | TerminatorKind::DropAndReplace { ref unwind, .. }
1243 | TerminatorKind::Drop { ref unwind, .. }
1244 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1248 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1250 TerminatorKind::Goto { .. }
1251 | TerminatorKind::Resume
1252 | TerminatorKind::Abort
1253 | TerminatorKind::Return
1254 | TerminatorKind::Unreachable
1255 | TerminatorKind::GeneratorDrop
1256 | TerminatorKind::Yield { .. }
1257 | TerminatorKind::SwitchInt { .. }
1258 | TerminatorKind::FalseEdges { .. } => None,
1259 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1260 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1261 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1262 | TerminatorKind::Drop { ref mut unwind, .. }
1263 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1268 impl<'tcx> BasicBlockData<'tcx> {
1269 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1270 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1273 /// Accessor for terminator.
1275 /// Terminator may not be None after construction of the basic block is complete. This accessor
1276 /// provides a convenience way to reach the terminator.
1277 pub fn terminator(&self) -> &Terminator<'tcx> {
1278 self.terminator.as_ref().expect("invalid terminator state")
1281 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1282 self.terminator.as_mut().expect("invalid terminator state")
1285 pub fn retain_statements<F>(&mut self, mut f: F)
1287 F: FnMut(&mut Statement<'_>) -> bool,
1289 for s in &mut self.statements {
1296 pub fn expand_statements<F, I>(&mut self, mut f: F)
1298 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1299 I: iter::TrustedLen<Item = Statement<'tcx>>,
1301 // Gather all the iterators we'll need to splice in, and their positions.
1302 let mut splices: Vec<(usize, I)> = vec![];
1303 let mut extra_stmts = 0;
1304 for (i, s) in self.statements.iter_mut().enumerate() {
1305 if let Some(mut new_stmts) = f(s) {
1306 if let Some(first) = new_stmts.next() {
1307 // We can already store the first new statement.
1310 // Save the other statements for optimized splicing.
1311 let remaining = new_stmts.size_hint().0;
1313 splices.push((i + 1 + extra_stmts, new_stmts));
1314 extra_stmts += remaining;
1322 // Splice in the new statements, from the end of the block.
1323 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1324 // where a range of elements ("gap") is left uninitialized, with
1325 // splicing adding new elements to the end of that gap and moving
1326 // existing elements from before the gap to the end of the gap.
1327 // For now, this is safe code, emulating a gap but initializing it.
1328 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1329 self.statements.resize(
1332 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1333 kind: StatementKind::Nop,
1336 for (splice_start, new_stmts) in splices.into_iter().rev() {
1337 let splice_end = splice_start + new_stmts.size_hint().0;
1338 while gap.end > splice_end {
1341 self.statements.swap(gap.start, gap.end);
1343 self.statements.splice(splice_start..splice_end, new_stmts);
1344 gap.end = splice_start;
1348 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1349 if index < self.statements.len() {
1350 &self.statements[index]
1357 impl<'tcx> Debug for TerminatorKind<'tcx> {
1358 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1359 self.fmt_head(fmt)?;
1360 let successor_count = self.successors().count();
1361 let labels = self.fmt_successor_labels();
1362 assert_eq!(successor_count, labels.len());
1364 match successor_count {
1367 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1370 write!(fmt, " -> [")?;
1371 for (i, target) in self.successors().enumerate() {
1375 write!(fmt, "{}: {:?}", labels[i], target)?;
1383 impl<'tcx> TerminatorKind<'tcx> {
1384 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1385 /// successor basic block, if any. The only information not included is the list of possible
1386 /// successors, which may be rendered differently between the text and the graphviz format.
1387 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1388 use self::TerminatorKind::*;
1390 Goto { .. } => write!(fmt, "goto"),
1391 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1392 Return => write!(fmt, "return"),
1393 GeneratorDrop => write!(fmt, "generator_drop"),
1394 Resume => write!(fmt, "resume"),
1395 Abort => write!(fmt, "abort"),
1396 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1397 Unreachable => write!(fmt, "unreachable"),
1398 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1399 DropAndReplace { ref location, ref value, .. } => {
1400 write!(fmt, "replace({:?} <- {:?})", location, value)
1402 Call { ref func, ref args, ref destination, .. } => {
1403 if let Some((ref destination, _)) = *destination {
1404 write!(fmt, "{:?} = ", destination)?;
1406 write!(fmt, "{:?}(", func)?;
1407 for (index, arg) in args.iter().enumerate() {
1411 write!(fmt, "{:?}", arg)?;
1415 Assert { ref cond, expected, ref msg, .. } => {
1416 write!(fmt, "assert(")?;
1420 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1422 FalseEdges { .. } => write!(fmt, "falseEdges"),
1423 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1427 /// Returns the list of labels for the edges to the successor basic blocks.
1428 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1429 use self::TerminatorKind::*;
1431 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1432 Goto { .. } => vec!["".into()],
1433 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1434 let param_env = ty::ParamEnv::empty();
1435 let switch_ty = tcx.lift(&switch_ty).unwrap();
1436 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1440 ty::Const::from_scalar(
1442 Scalar::from_uint(u, size).into(),
1448 .chain(iter::once("otherwise".into()))
1451 Call { destination: Some(_), cleanup: Some(_), .. } => {
1452 vec!["return".into(), "unwind".into()]
1454 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1455 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1456 Call { destination: None, cleanup: None, .. } => vec![],
1457 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1458 Yield { drop: None, .. } => vec!["resume".into()],
1459 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1460 vec!["return".into()]
1462 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1463 vec!["return".into(), "unwind".into()]
1465 Assert { cleanup: None, .. } => vec!["".into()],
1466 Assert { .. } => vec!["success".into(), "unwind".into()],
1467 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1468 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1469 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1474 ///////////////////////////////////////////////////////////////////////////
1477 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1478 pub struct Statement<'tcx> {
1479 pub source_info: SourceInfo,
1480 pub kind: StatementKind<'tcx>,
1483 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1484 #[cfg(target_arch = "x86_64")]
1485 static_assert_size!(Statement<'_>, 32);
1487 impl Statement<'_> {
1488 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1489 /// invalidating statement indices in `Location`s.
1490 pub fn make_nop(&mut self) {
1491 self.kind = StatementKind::Nop
1494 /// Changes a statement to a nop and returns the original statement.
1495 pub fn replace_nop(&mut self) -> Self {
1497 source_info: self.source_info,
1498 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1503 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1504 pub enum StatementKind<'tcx> {
1505 /// Write the RHS Rvalue to the LHS Place.
1506 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1508 /// This represents all the reading that a pattern match may do
1509 /// (e.g., inspecting constants and discriminant values), and the
1510 /// kind of pattern it comes from. This is in order to adapt potential
1511 /// error messages to these specific patterns.
1513 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1514 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1515 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1517 /// Write the discriminant for a variant to the enum Place.
1518 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1520 /// Start a live range for the storage of the local.
1523 /// End the current live range for the storage of the local.
1526 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1527 /// of `StatementKind` low.
1528 InlineAsm(Box<InlineAsm<'tcx>>),
1530 /// Retag references in the given place, ensuring they got fresh tags. This is
1531 /// part of the Stacked Borrows model. These statements are currently only interpreted
1532 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1533 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1534 /// for more details.
1535 Retag(RetagKind, Box<Place<'tcx>>),
1537 /// Encodes a user's type ascription. These need to be preserved
1538 /// intact so that NLL can respect them. For example:
1542 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1543 /// to the user-given type `T`. The effect depends on the specified variance:
1545 /// - `Covariant` -- requires that `T_y <: T`
1546 /// - `Contravariant` -- requires that `T_y :> T`
1547 /// - `Invariant` -- requires that `T_y == T`
1548 /// - `Bivariant` -- no effect
1549 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1551 /// No-op. Useful for deleting instructions without affecting statement indices.
1555 /// Describes what kind of retag is to be performed.
1556 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1557 pub enum RetagKind {
1558 /// The initial retag when entering a function.
1560 /// Retag preparing for a two-phase borrow.
1562 /// Retagging raw pointers.
1564 /// A "normal" retag.
1568 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1569 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable, PartialEq)]
1570 pub enum FakeReadCause {
1571 /// Inject a fake read of the borrowed input at the end of each guards
1574 /// This should ensure that you cannot change the variant for an enum while
1575 /// you are in the midst of matching on it.
1578 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1579 /// generate a read of x to check that it is initialized and safe.
1582 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1583 /// in a match guard to ensure that it's value hasn't change by the time
1584 /// we create the OutsideGuard version.
1587 /// Officially, the semantics of
1589 /// `let pattern = <expr>;`
1591 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1592 /// into the pattern.
1594 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1595 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1596 /// but in some cases it can affect the borrow checker, as in #53695.
1597 /// Therefore, we insert a "fake read" here to ensure that we get
1598 /// appropriate errors.
1601 /// If we have an index expression like
1603 /// (*x)[1][{ x = y; 4}]
1605 /// then the first bounds check is invalidated when we evaluate the second
1606 /// index expression. Thus we create a fake borrow of `x` across the second
1607 /// indexer, which will cause a borrow check error.
1611 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1612 pub struct InlineAsm<'tcx> {
1613 pub asm: hir::InlineAsmInner,
1614 pub outputs: Box<[Place<'tcx>]>,
1615 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1618 impl Debug for Statement<'_> {
1619 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1620 use self::StatementKind::*;
1622 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1623 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1624 Retag(ref kind, ref place) => write!(
1628 RetagKind::FnEntry => "[fn entry] ",
1629 RetagKind::TwoPhase => "[2phase] ",
1630 RetagKind::Raw => "[raw] ",
1631 RetagKind::Default => "",
1635 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1636 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1637 SetDiscriminant { ref place, variant_index } => {
1638 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1640 InlineAsm(ref asm) => {
1641 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1643 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1644 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1646 Nop => write!(fmt, "nop"),
1651 ///////////////////////////////////////////////////////////////////////////
1654 /// A path to a value; something that can be evaluated without
1655 /// changing or disturbing program state.
1657 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1659 pub struct Place<'tcx> {
1660 pub base: PlaceBase<'tcx>,
1662 /// projection out of a place (access a field, deref a pointer, etc)
1663 pub projection: &'tcx List<PlaceElem<'tcx>>,
1666 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1669 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1671 pub enum PlaceBase<'tcx> {
1675 /// static or static mut variable
1676 Static(Box<Static<'tcx>>),
1679 /// We store the normalized type to avoid requiring normalization when reading MIR
1680 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
1681 RustcEncodable, RustcDecodable, HashStable)]
1682 pub struct Static<'tcx> {
1684 pub kind: StaticKind<'tcx>,
1685 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1686 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1687 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1688 /// into the calling frame.
1693 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1695 pub enum StaticKind<'tcx> {
1696 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1697 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1698 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1699 Promoted(Promoted, SubstsRef<'tcx>),
1703 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1704 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1705 pub enum ProjectionElem<V, T> {
1710 /// These indices are generated by slice patterns. Easiest to explain
1714 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1715 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1716 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1717 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1720 /// index or -index (in Python terms), depending on from_end
1722 /// thing being indexed must be at least this long
1724 /// counting backwards from end?
1728 /// These indices are generated by slice patterns.
1730 /// slice[from:-to] in Python terms.
1736 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1737 /// this for ADTs with more than one variant. It may be better to
1738 /// just introduce it always, or always for enums.
1740 /// The included Symbol is the name of the variant, used for printing MIR.
1741 Downcast(Option<Symbol>, VariantIdx),
1744 impl<V, T> ProjectionElem<V, T> {
1745 /// Returns `true` if the target of this projection may refer to a different region of memory
1747 fn is_indirect(&self) -> bool {
1749 Self::Deref => true,
1753 | Self::ConstantIndex { .. }
1754 | Self::Subslice { .. }
1755 | Self::Downcast(_, _)
1761 /// Alias for projections as they appear in places, where the base is a place
1762 /// and the index is a local.
1763 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1765 impl<'tcx> Copy for PlaceElem<'tcx> { }
1767 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1768 #[cfg(target_arch = "x86_64")]
1769 static_assert_size!(PlaceElem<'_>, 16);
1771 /// Alias for projections as they appear in `UserTypeProjection`, where we
1772 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1773 pub type ProjectionKind = ProjectionElem<(), ()>;
1775 rustc_index::newtype_index! {
1778 DEBUG_FORMAT = "field[{}]"
1782 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1783 pub struct PlaceRef<'a, 'tcx> {
1784 pub base: &'a PlaceBase<'tcx>,
1785 pub projection: &'a [PlaceElem<'tcx>],
1788 impl<'tcx> Place<'tcx> {
1789 // FIXME change this to a const fn by also making List::empty a const fn.
1790 pub fn return_place() -> Place<'tcx> {
1792 base: PlaceBase::Local(RETURN_PLACE),
1793 projection: List::empty(),
1797 /// Returns `true` if this `Place` contains a `Deref` projection.
1799 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1800 /// same region of memory as its base.
1801 pub fn is_indirect(&self) -> bool {
1802 self.projection.iter().any(|elem| elem.is_indirect())
1805 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1806 /// a single deref of a local.
1808 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1809 pub fn local_or_deref_local(&self) -> Option<Local> {
1810 match self.as_ref() {
1812 base: &PlaceBase::Local(local),
1816 base: &PlaceBase::Local(local),
1817 projection: &[ProjectionElem::Deref],
1823 /// If this place represents a local variable like `_X` with no
1824 /// projections, return `Some(_X)`.
1825 pub fn as_local(&self) -> Option<Local> {
1826 self.as_ref().as_local()
1829 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1832 projection: &self.projection,
1837 impl From<Local> for Place<'_> {
1838 fn from(local: Local) -> Self {
1841 projection: List::empty(),
1846 impl From<Local> for PlaceBase<'_> {
1847 fn from(local: Local) -> Self {
1848 PlaceBase::Local(local)
1852 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1853 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1854 /// a single deref of a local.
1856 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1857 pub fn local_or_deref_local(&self) -> Option<Local> {
1860 base: PlaceBase::Local(local),
1864 base: PlaceBase::Local(local),
1865 projection: [ProjectionElem::Deref],
1871 /// If this place represents a local variable like `_X` with no
1872 /// projections, return `Some(_X)`.
1873 pub fn as_local(&self) -> Option<Local> {
1875 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1881 impl Debug for Place<'_> {
1882 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1883 for elem in self.projection.iter().rev() {
1885 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1886 write!(fmt, "(").unwrap();
1888 ProjectionElem::Deref => {
1889 write!(fmt, "(*").unwrap();
1891 ProjectionElem::Index(_)
1892 | ProjectionElem::ConstantIndex { .. }
1893 | ProjectionElem::Subslice { .. } => {}
1897 write!(fmt, "{:?}", self.base)?;
1899 for elem in self.projection.iter() {
1901 ProjectionElem::Downcast(Some(name), _index) => {
1902 write!(fmt, " as {})", name)?;
1904 ProjectionElem::Downcast(None, index) => {
1905 write!(fmt, " as variant#{:?})", index)?;
1907 ProjectionElem::Deref => {
1910 ProjectionElem::Field(field, ty) => {
1911 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1913 ProjectionElem::Index(ref index) => {
1914 write!(fmt, "[{:?}]", index)?;
1916 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1917 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1919 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1920 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1922 ProjectionElem::Subslice { from, to } if *to == 0 => {
1923 write!(fmt, "[{:?}:]", from)?;
1925 ProjectionElem::Subslice { from, to } if *from == 0 => {
1926 write!(fmt, "[:-{:?}]", to)?;
1928 ProjectionElem::Subslice { from, to } => {
1929 write!(fmt, "[{:?}:-{:?}]", from, to)?;
1938 impl Debug for PlaceBase<'_> {
1939 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1941 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
1942 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
1943 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
1945 PlaceBase::Static(box self::Static {
1946 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
1948 write!(fmt, "({:?}: {:?})", promoted, ty)
1954 ///////////////////////////////////////////////////////////////////////////
1957 rustc_index::newtype_index! {
1958 pub struct SourceScope {
1960 DEBUG_FORMAT = "scope[{}]",
1961 const OUTERMOST_SOURCE_SCOPE = 0,
1965 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1966 pub struct SourceScopeData {
1968 pub parent_scope: Option<SourceScope>,
1970 /// Crate-local information for this source scope, that can't (and
1971 /// needn't) be tracked across crates.
1972 pub local_data: ClearCrossCrate<SourceScopeLocalData>,
1975 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1976 pub struct SourceScopeLocalData {
1977 /// An `HirId` with lint levels equivalent to this scope's lint levels.
1978 pub lint_root: hir::HirId,
1979 /// The unsafe block that contains this node.
1983 ///////////////////////////////////////////////////////////////////////////
1986 /// These are values that can appear inside an rvalue. They are intentionally
1987 /// limited to prevent rvalues from being nested in one another.
1988 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
1989 pub enum Operand<'tcx> {
1990 /// Copy: The value must be available for use afterwards.
1992 /// This implies that the type of the place must be `Copy`; this is true
1993 /// by construction during build, but also checked by the MIR type checker.
1996 /// Move: The value (including old borrows of it) will not be used again.
1998 /// Safe for values of all types (modulo future developments towards `?Move`).
1999 /// Correct usage patterns are enforced by the borrow checker for safe code.
2000 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2003 /// Synthesizes a constant value.
2004 Constant(Box<Constant<'tcx>>),
2007 impl<'tcx> Debug for Operand<'tcx> {
2008 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2009 use self::Operand::*;
2011 Constant(ref a) => write!(fmt, "{:?}", a),
2012 Copy(ref place) => write!(fmt, "{:?}", place),
2013 Move(ref place) => write!(fmt, "move {:?}", place),
2018 impl<'tcx> Operand<'tcx> {
2019 /// Convenience helper to make a constant that refers to the fn
2020 /// with given `DefId` and substs. Since this is used to synthesize
2021 /// MIR, assumes `user_ty` is None.
2022 pub fn function_handle(
2025 substs: SubstsRef<'tcx>,
2028 let ty = tcx.type_of(def_id).subst(tcx, substs);
2029 Operand::Constant(box Constant {
2032 literal: ty::Const::zero_sized(tcx, ty),
2036 pub fn to_copy(&self) -> Self {
2038 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2039 Operand::Move(ref place) => Operand::Copy(place.clone()),
2044 ///////////////////////////////////////////////////////////////////////////
2047 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2048 pub enum Rvalue<'tcx> {
2049 /// x (either a move or copy, depending on type of x)
2053 Repeat(Operand<'tcx>, u64),
2056 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2058 /// length of a [X] or [X;n] value
2061 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2063 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2064 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2066 NullaryOp(NullOp, Ty<'tcx>),
2067 UnaryOp(UnOp, Operand<'tcx>),
2069 /// Read the discriminant of an ADT.
2071 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2072 /// be defined to return, say, a 0) if ADT is not an enum.
2073 Discriminant(Place<'tcx>),
2075 /// Creates an aggregate value, like a tuple or struct. This is
2076 /// only needed because we want to distinguish `dest = Foo { x:
2077 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2078 /// that `Foo` has a destructor. These rvalues can be optimized
2079 /// away after type-checking and before lowering.
2080 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2083 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2086 Pointer(PointerCast),
2089 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2090 pub enum AggregateKind<'tcx> {
2091 /// The type is of the element
2095 /// The second field is the variant index. It's equal to 0 for struct
2096 /// and union expressions. The fourth field is
2097 /// active field number and is present only for union expressions
2098 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2099 /// active field index would identity the field `c`
2100 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2102 Closure(DefId, SubstsRef<'tcx>),
2103 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2106 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2108 /// The `+` operator (addition)
2110 /// The `-` operator (subtraction)
2112 /// The `*` operator (multiplication)
2114 /// The `/` operator (division)
2116 /// The `%` operator (modulus)
2118 /// The `^` operator (bitwise xor)
2120 /// The `&` operator (bitwise and)
2122 /// The `|` operator (bitwise or)
2124 /// The `<<` operator (shift left)
2126 /// The `>>` operator (shift right)
2128 /// The `==` operator (equality)
2130 /// The `<` operator (less than)
2132 /// The `<=` operator (less than or equal to)
2134 /// The `!=` operator (not equal to)
2136 /// The `>=` operator (greater than or equal to)
2138 /// The `>` operator (greater than)
2140 /// The `ptr.offset` operator
2145 pub fn is_checkable(self) -> bool {
2148 Add | Sub | Mul | Shl | Shr => true,
2154 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2156 /// Returns the size of a value of that type
2158 /// Creates a new uninitialized box for a value of that type
2162 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2164 /// The `!` operator for logical inversion
2166 /// The `-` operator for negation
2170 impl<'tcx> Debug for Rvalue<'tcx> {
2171 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2172 use self::Rvalue::*;
2175 Use(ref place) => write!(fmt, "{:?}", place),
2176 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2177 Len(ref a) => write!(fmt, "Len({:?})", a),
2178 Cast(ref kind, ref place, ref ty) => {
2179 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2181 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2182 CheckedBinaryOp(ref op, ref a, ref b) => {
2183 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2185 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2186 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2187 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2188 Ref(region, borrow_kind, ref place) => {
2189 let kind_str = match borrow_kind {
2190 BorrowKind::Shared => "",
2191 BorrowKind::Shallow => "shallow ",
2192 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2195 // When printing regions, add trailing space if necessary.
2196 let print_region = ty::tls::with(|tcx| {
2197 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2199 let region = if print_region {
2200 let mut region = region.to_string();
2201 if region.len() > 0 {
2206 // Do not even print 'static
2209 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2212 Aggregate(ref kind, ref places) => {
2213 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2214 let mut tuple_fmt = fmt.debug_tuple("");
2215 for place in places {
2216 tuple_fmt.field(place);
2222 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2224 AggregateKind::Tuple => match places.len() {
2225 0 => write!(fmt, "()"),
2226 1 => write!(fmt, "({:?},)", places[0]),
2227 _ => fmt_tuple(fmt, places),
2230 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2231 let variant_def = &adt_def.variants[variant];
2234 ty::tls::with(|tcx| {
2235 let substs = tcx.lift(&substs).expect("could not lift for printing");
2236 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2237 .print_def_path(variant_def.def_id, substs)?;
2241 match variant_def.ctor_kind {
2242 CtorKind::Const => Ok(()),
2243 CtorKind::Fn => fmt_tuple(fmt, places),
2244 CtorKind::Fictive => {
2245 let mut struct_fmt = fmt.debug_struct("");
2246 for (field, place) in variant_def.fields.iter().zip(places) {
2247 struct_fmt.field(&field.ident.as_str(), place);
2254 AggregateKind::Closure(def_id, substs) => ty::tls::with(|tcx| {
2255 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2256 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2257 let substs = tcx.lift(&substs).unwrap();
2260 tcx.def_path_str_with_substs(def_id, substs),
2263 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2265 let mut struct_fmt = fmt.debug_struct(&name);
2267 if let Some(upvars) = tcx.upvars(def_id) {
2268 for (&var_id, place) in upvars.keys().zip(places) {
2269 let var_name = tcx.hir().name(var_id);
2270 struct_fmt.field(&var_name.as_str(), place);
2276 write!(fmt, "[closure]")
2280 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2281 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2282 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2283 let mut struct_fmt = fmt.debug_struct(&name);
2285 if let Some(upvars) = tcx.upvars(def_id) {
2286 for (&var_id, place) in upvars.keys().zip(places) {
2287 let var_name = tcx.hir().name(var_id);
2288 struct_fmt.field(&var_name.as_str(), place);
2294 write!(fmt, "[generator]")
2303 ///////////////////////////////////////////////////////////////////////////
2306 /// Two constants are equal if they are the same constant. Note that
2307 /// this does not necessarily mean that they are "==" in Rust -- in
2308 /// particular one must be wary of `NaN`!
2310 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2311 pub struct Constant<'tcx> {
2314 /// Optional user-given type: for something like
2315 /// `collect::<Vec<_>>`, this would be present and would
2316 /// indicate that `Vec<_>` was explicitly specified.
2318 /// Needed for NLL to impose user-given type constraints.
2319 pub user_ty: Option<UserTypeAnnotationIndex>,
2321 pub literal: &'tcx ty::Const<'tcx>,
2324 impl Constant<'tcx> {
2325 pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
2326 match self.literal.val.try_to_scalar() {
2327 Some(Scalar::Ptr(ptr)) => match tcx.alloc_map.lock().get(ptr.alloc_id) {
2328 Some(GlobalAlloc::Static(def_id)) => Some(def_id),
2331 tcx.sess.delay_span_bug(
2332 DUMMY_SP, "MIR cannot contain dangling const pointers",
2342 /// A collection of projections into user types.
2344 /// They are projections because a binding can occur a part of a
2345 /// parent pattern that has been ascribed a type.
2347 /// Its a collection because there can be multiple type ascriptions on
2348 /// the path from the root of the pattern down to the binding itself.
2353 /// struct S<'a>((i32, &'a str), String);
2354 /// let S((_, w): (i32, &'static str), _): S = ...;
2355 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2356 /// // --------------------------------- ^ (2)
2359 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2360 /// ascribed the type `(i32, &'static str)`.
2362 /// The highlights labelled `(2)` show the whole pattern being
2363 /// ascribed the type `S`.
2365 /// In this example, when we descend to `w`, we will have built up the
2366 /// following two projected types:
2368 /// * base: `S`, projection: `(base.0).1`
2369 /// * base: `(i32, &'static str)`, projection: `base.1`
2371 /// The first will lead to the constraint `w: &'1 str` (for some
2372 /// inferred region `'1`). The second will lead to the constraint `w:
2374 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2375 pub struct UserTypeProjections {
2376 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2379 impl<'tcx> UserTypeProjections {
2380 pub fn none() -> Self {
2381 UserTypeProjections { contents: vec![] }
2384 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2385 UserTypeProjections { contents: projs.collect() }
2388 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2389 self.contents.iter()
2392 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2393 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2396 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2397 self.contents.push((user_ty.clone(), span));
2403 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2405 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2409 pub fn index(self) -> Self {
2410 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2413 pub fn subslice(self, from: u32, to: u32) -> Self {
2414 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2417 pub fn deref(self) -> Self {
2418 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2421 pub fn leaf(self, field: Field) -> Self {
2422 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2425 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2426 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2430 /// Encodes the effect of a user-supplied type annotation on the
2431 /// subcomponents of a pattern. The effect is determined by applying the
2432 /// given list of proejctions to some underlying base type. Often,
2433 /// the projection element list `projs` is empty, in which case this
2434 /// directly encodes a type in `base`. But in the case of complex patterns with
2435 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2436 /// in which case the `projs` vector is used.
2440 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2442 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2443 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2444 /// determined by finding the type of the `.0` field from `T`.
2445 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2446 pub struct UserTypeProjection {
2447 pub base: UserTypeAnnotationIndex,
2448 pub projs: Vec<ProjectionKind>,
2451 impl Copy for ProjectionKind {}
2453 impl UserTypeProjection {
2454 pub(crate) fn index(mut self) -> Self {
2455 self.projs.push(ProjectionElem::Index(()));
2459 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2460 self.projs.push(ProjectionElem::Subslice { from, to });
2464 pub(crate) fn deref(mut self) -> Self {
2465 self.projs.push(ProjectionElem::Deref);
2469 pub(crate) fn leaf(mut self, field: Field) -> Self {
2470 self.projs.push(ProjectionElem::Field(field, ()));
2474 pub(crate) fn variant(
2476 adt_def: &'tcx AdtDef,
2477 variant_index: VariantIdx,
2480 self.projs.push(ProjectionElem::Downcast(
2481 Some(adt_def.variants[variant_index].ident.name),
2484 self.projs.push(ProjectionElem::Field(field, ()));
2489 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2491 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2492 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2493 use crate::mir::ProjectionElem::*;
2495 let base = self.base.fold_with(folder);
2496 let projs: Vec<_> = self
2499 .map(|elem| match elem {
2501 Field(f, ()) => Field(f.clone(), ()),
2502 Index(()) => Index(()),
2503 elem => elem.clone(),
2507 UserTypeProjection { base, projs }
2510 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2511 self.base.visit_with(visitor)
2512 // Note: there's nothing in `self.proj` to visit.
2516 rustc_index::newtype_index! {
2517 pub struct Promoted {
2519 DEBUG_FORMAT = "promoted[{}]"
2523 impl<'tcx> Debug for Constant<'tcx> {
2524 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2525 write!(fmt, "{}", self)
2529 impl<'tcx> Display for Constant<'tcx> {
2530 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2531 write!(fmt, "const ")?;
2532 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2533 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2534 // detailed and just not '{pointer}'.
2535 if let ty::RawPtr(_) = self.literal.ty.kind {
2536 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2538 write!(fmt, "{}", self.literal)
2543 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2544 type Node = BasicBlock;
2547 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2548 fn num_nodes(&self) -> usize {
2549 self.basic_blocks.len()
2553 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2554 fn start_node(&self) -> Self::Node {
2559 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2563 ) -> <Self as GraphSuccessors<'_>>::Iter {
2564 self.basic_blocks[node].terminator().successors().cloned()
2568 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2569 type Item = BasicBlock;
2570 type Iter = iter::Cloned<Successors<'b>>;
2573 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2574 pub struct Location {
2575 /// The block that the location is within.
2576 pub block: BasicBlock,
2578 /// The location is the position of the start of the statement; or, if
2579 /// `statement_index` equals the number of statements, then the start of the
2581 pub statement_index: usize,
2584 impl fmt::Debug for Location {
2585 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2586 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2591 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2593 /// Returns the location immediately after this one within the enclosing block.
2595 /// Note that if this location represents a terminator, then the
2596 /// resulting location would be out of bounds and invalid.
2597 pub fn successor_within_block(&self) -> Location {
2598 Location { block: self.block, statement_index: self.statement_index + 1 }
2601 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2602 pub fn is_predecessor_of<'tcx>(
2605 body: ReadOnlyBodyCache<'_, 'tcx>
2607 // If we are in the same block as the other location and are an earlier statement
2608 // then we are a predecessor of `other`.
2609 if self.block == other.block && self.statement_index < other.statement_index {
2613 // If we're in another block, then we want to check that block is a predecessor of `other`.
2614 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).to_vec();
2615 let mut visited = FxHashSet::default();
2617 while let Some(block) = queue.pop() {
2618 // If we haven't visited this block before, then make sure we visit it's predecessors.
2619 if visited.insert(block) {
2620 queue.extend(body.predecessors_for(block).iter().cloned());
2625 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2626 // we found that block by looking at the predecessors of `other`).
2627 if self.block == block {
2635 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2636 if self.block == other.block {
2637 self.statement_index <= other.statement_index
2639 dominators.is_dominated_by(other.block, self.block)
2644 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2645 pub enum UnsafetyViolationKind {
2647 /// Permitted both in `const fn`s and regular `fn`s.
2649 BorrowPacked(hir::HirId),
2652 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2653 pub struct UnsafetyViolation {
2654 pub source_info: SourceInfo,
2655 pub description: Symbol,
2656 pub details: Symbol,
2657 pub kind: UnsafetyViolationKind,
2660 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2661 pub struct UnsafetyCheckResult {
2662 /// Violations that are propagated *upwards* from this function.
2663 pub violations: Lrc<[UnsafetyViolation]>,
2664 /// `unsafe` blocks in this function, along with whether they are used. This is
2665 /// used for the "unused_unsafe" lint.
2666 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2669 rustc_index::newtype_index! {
2670 pub struct GeneratorSavedLocal {
2672 DEBUG_FORMAT = "_{}",
2676 /// The layout of generator state.
2677 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2678 pub struct GeneratorLayout<'tcx> {
2679 /// The type of every local stored inside the generator.
2680 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2682 /// Which of the above fields are in each variant. Note that one field may
2683 /// be stored in multiple variants.
2684 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2686 /// Which saved locals are storage-live at the same time. Locals that do not
2687 /// have conflicts with each other are allowed to overlap in the computed
2689 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2692 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2693 pub struct BorrowCheckResult<'tcx> {
2694 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2695 pub used_mut_upvars: SmallVec<[Field; 8]>,
2698 /// The result of the `mir_const_qualif` query.
2700 /// Each field corresponds to an implementer of the `Qualif` trait in
2701 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2703 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2704 pub struct ConstQualifs {
2705 pub has_mut_interior: bool,
2706 pub needs_drop: bool,
2709 /// After we borrow check a closure, we are left with various
2710 /// requirements that we have inferred between the free regions that
2711 /// appear in the closure's signature or on its field types. These
2712 /// requirements are then verified and proved by the closure's
2713 /// creating function. This struct encodes those requirements.
2715 /// The requirements are listed as being between various
2716 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2717 /// vids refer to the free regions that appear in the closure (or
2718 /// generator's) type, in order of appearance. (This numbering is
2719 /// actually defined by the `UniversalRegions` struct in the NLL
2720 /// region checker. See for example
2721 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2722 /// regions in the closure's type "as if" they were erased, so their
2723 /// precise identity is not important, only their position.
2725 /// Example: If type check produces a closure with the closure substs:
2728 /// ClosureSubsts = [
2729 /// i8, // the "closure kind"
2730 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2731 /// &'a String, // some upvar
2735 /// here, there is one unique free region (`'a`) but it appears
2736 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2739 /// ClosureSubsts = [
2740 /// i8, // the "closure kind"
2741 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2742 /// &'2 String, // some upvar
2746 /// Now the code might impose a requirement like `'1: '2`. When an
2747 /// instance of the closure is created, the corresponding free regions
2748 /// can be extracted from its type and constrained to have the given
2749 /// outlives relationship.
2751 /// In some cases, we have to record outlives requirements between
2752 /// types and regions as well. In that case, if those types include
2753 /// any regions, those regions are recorded as `ReClosureBound`
2754 /// instances assigned one of these same indices. Those regions will
2755 /// be substituted away by the creator. We use `ReClosureBound` in
2756 /// that case because the regions must be allocated in the global
2757 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2758 /// internally within the rest of the NLL code).
2759 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2760 pub struct ClosureRegionRequirements<'tcx> {
2761 /// The number of external regions defined on the closure. In our
2762 /// example above, it would be 3 -- one for `'static`, then `'1`
2763 /// and `'2`. This is just used for a sanity check later on, to
2764 /// make sure that the number of regions we see at the callsite
2766 pub num_external_vids: usize,
2768 /// Requirements between the various free regions defined in
2770 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2773 /// Indicates an outlives-constraint between a type or between two
2774 /// free regions declared on the closure.
2775 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2776 pub struct ClosureOutlivesRequirement<'tcx> {
2777 // This region or type ...
2778 pub subject: ClosureOutlivesSubject<'tcx>,
2780 // ... must outlive this one.
2781 pub outlived_free_region: ty::RegionVid,
2783 // If not, report an error here ...
2784 pub blame_span: Span,
2786 // ... due to this reason.
2787 pub category: ConstraintCategory,
2790 /// Outlives-constraints can be categorized to determine whether and why they
2791 /// are interesting (for error reporting). Order of variants indicates sort
2792 /// order of the category, thereby influencing diagnostic output.
2794 /// See also [rustc_mir::borrow_check::nll::constraints].
2808 pub enum ConstraintCategory {
2816 /// A constraint that came from checking the body of a closure.
2818 /// We try to get the category that the closure used when reporting this.
2826 /// A "boring" constraint (caused by the given location) is one that
2827 /// the user probably doesn't want to see described in diagnostics,
2828 /// because it is kind of an artifact of the type system setup.
2829 /// Example: `x = Foo { field: y }` technically creates
2830 /// intermediate regions representing the "type of `Foo { field: y
2831 /// }`", and data flows from `y` into those variables, but they
2832 /// are not very interesting. The assignment into `x` on the other
2835 // Boring and applicable everywhere.
2838 /// A constraint that doesn't correspond to anything the user sees.
2842 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2843 /// that must outlive some region.
2844 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2845 pub enum ClosureOutlivesSubject<'tcx> {
2846 /// Subject is a type, typically a type parameter, but could also
2847 /// be a projection. Indicates a requirement like `T: 'a` being
2848 /// passed to the caller, where the type here is `T`.
2850 /// The type here is guaranteed not to contain any free regions at
2854 /// Subject is a free region from the closure. Indicates a requirement
2855 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2856 Region(ty::RegionVid),
2860 * `TypeFoldable` implementations for MIR types
2863 CloneTypeFoldableAndLiftImpls! {
2872 SourceScopeLocalData,
2873 UserTypeAnnotationIndex,
2876 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2877 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2878 use crate::mir::TerminatorKind::*;
2880 let kind = match self.kind {
2881 Goto { target } => Goto { target },
2882 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2883 discr: discr.fold_with(folder),
2884 switch_ty: switch_ty.fold_with(folder),
2885 values: values.clone(),
2886 targets: targets.clone(),
2888 Drop { ref location, target, unwind } => {
2889 Drop { location: location.fold_with(folder), target, unwind }
2891 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2892 location: location.fold_with(folder),
2893 value: value.fold_with(folder),
2897 Yield { ref value, resume, drop } => {
2898 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2900 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2902 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2905 func: func.fold_with(folder),
2906 args: args.fold_with(folder),
2912 Assert { ref cond, expected, ref msg, target, cleanup } => {
2914 let msg = match msg {
2915 BoundsCheck { ref len, ref index } =>
2917 len: len.fold_with(folder),
2918 index: index.fold_with(folder),
2920 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2921 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2924 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2926 GeneratorDrop => GeneratorDrop,
2930 Unreachable => Unreachable,
2931 FalseEdges { real_target, imaginary_target } => {
2932 FalseEdges { real_target, imaginary_target }
2934 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
2936 Terminator { source_info: self.source_info, kind }
2939 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2940 use crate::mir::TerminatorKind::*;
2943 SwitchInt { ref discr, switch_ty, .. } => {
2944 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
2946 Drop { ref location, .. } => location.visit_with(visitor),
2947 DropAndReplace { ref location, ref value, .. } => {
2948 location.visit_with(visitor) || value.visit_with(visitor)
2950 Yield { ref value, .. } => value.visit_with(visitor),
2951 Call { ref func, ref args, ref destination, .. } => {
2952 let dest = if let Some((ref loc, _)) = *destination {
2953 loc.visit_with(visitor)
2957 dest || func.visit_with(visitor) || args.visit_with(visitor)
2959 Assert { ref cond, ref msg, .. } => {
2960 if cond.visit_with(visitor) {
2963 BoundsCheck { ref len, ref index } =>
2964 len.visit_with(visitor) || index.visit_with(visitor),
2965 Panic { .. } | Overflow(_) | OverflowNeg |
2966 DivisionByZero | RemainderByZero |
2967 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2981 | FalseUnwind { .. } => false,
2986 impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
2987 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
2991 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
2996 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2997 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2999 base: self.base.fold_with(folder),
3000 projection: self.projection.fold_with(folder),
3004 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3005 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3009 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3010 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3012 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3013 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3017 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3019 PlaceBase::Local(local) => local.visit_with(visitor),
3020 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3025 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3026 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3027 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3028 folder.tcx().intern_place_elems(&v)
3031 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3032 self.iter().any(|t| t.visit_with(visitor))
3036 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3037 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3039 ty: self.ty.fold_with(folder),
3040 kind: self.kind.fold_with(folder),
3041 def_id: self.def_id,
3045 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3046 let Static { ty, kind, def_id: _ } = self;
3048 ty.visit_with(visitor) || kind.visit_with(visitor)
3052 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3053 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3055 StaticKind::Promoted(promoted, substs) =>
3056 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3057 StaticKind::Static => StaticKind::Static
3061 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3063 StaticKind::Promoted(promoted, substs) =>
3064 promoted.visit_with(visitor) || substs.visit_with(visitor),
3065 StaticKind::Static => { false }
3070 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3071 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3072 use crate::mir::Rvalue::*;
3074 Use(ref op) => Use(op.fold_with(folder)),
3075 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3076 Ref(region, bk, ref place) => {
3077 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3079 Len(ref place) => Len(place.fold_with(folder)),
3080 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3081 BinaryOp(op, ref rhs, ref lhs) => {
3082 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3084 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3085 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3087 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3088 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3089 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3090 Aggregate(ref kind, ref fields) => {
3091 let kind = box match **kind {
3092 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3093 AggregateKind::Tuple => AggregateKind::Tuple,
3094 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3097 substs.fold_with(folder),
3098 user_ty.fold_with(folder),
3101 AggregateKind::Closure(id, substs) => {
3102 AggregateKind::Closure(id, substs.fold_with(folder))
3104 AggregateKind::Generator(id, substs, movablity) => {
3105 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3108 Aggregate(kind, fields.fold_with(folder))
3113 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3114 use crate::mir::Rvalue::*;
3116 Use(ref op) => op.visit_with(visitor),
3117 Repeat(ref op, _) => op.visit_with(visitor),
3118 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3119 Len(ref place) => place.visit_with(visitor),
3120 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3121 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3122 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3124 UnaryOp(_, ref val) => val.visit_with(visitor),
3125 Discriminant(ref place) => place.visit_with(visitor),
3126 NullaryOp(_, ty) => ty.visit_with(visitor),
3127 Aggregate(ref kind, ref fields) => {
3129 AggregateKind::Array(ty) => ty.visit_with(visitor),
3130 AggregateKind::Tuple => false,
3131 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3132 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3134 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3135 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3136 }) || fields.visit_with(visitor)
3142 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3143 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3145 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3146 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3147 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3151 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3153 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3154 Operand::Constant(ref c) => c.visit_with(visitor),
3159 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3160 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3161 use crate::mir::ProjectionElem::*;
3165 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3166 Index(v) => Index(v.fold_with(folder)),
3167 elem => elem.clone(),
3171 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3172 use crate::mir::ProjectionElem::*;
3175 Field(_, ty) => ty.visit_with(visitor),
3176 Index(v) => v.visit_with(visitor),
3182 impl<'tcx> TypeFoldable<'tcx> for Field {
3183 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3186 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3191 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3192 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3195 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3200 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3201 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3204 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3209 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3210 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3212 span: self.span.clone(),
3213 user_ty: self.user_ty.fold_with(folder),
3214 literal: self.literal.fold_with(folder),
3217 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3218 self.literal.visit_with(visitor)