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 pub use crate::mir::cache::{BodyCache, ReadOnlyBodyCache};
42 pub use crate::read_only;
52 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
54 pub trait HasLocalDecls<'tcx> {
55 fn local_decls(&self) -> &LocalDecls<'tcx>;
58 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
59 fn local_decls(&self) -> &LocalDecls<'tcx> {
64 impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
65 fn local_decls(&self) -> &LocalDecls<'tcx> {
70 /// The various "big phases" that MIR goes through.
72 /// Warning: ordering of variants is significant.
73 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, HashStable,
74 Debug, PartialEq, Eq, PartialOrd, Ord)]
83 /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
84 pub fn phase_index(&self) -> usize {
89 /// The lowered representation of a single function.
90 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable, TypeFoldable)]
91 pub struct Body<'tcx> {
92 /// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
93 /// that indexes into this vector.
94 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
96 /// Records how far through the "desugaring and optimization" process this particular
97 /// MIR has traversed. This is particularly useful when inlining, since in that context
98 /// we instantiate the promoted constants and add them to our promoted vector -- but those
99 /// promoted items have already been optimized, whereas ours have not. This field allows
100 /// us to see the difference and forego optimization on the inlined promoted items.
103 /// A list of source scopes; these are referenced by statements
104 /// and used for debuginfo. Indexed by a `SourceScope`.
105 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
107 /// The yield type of the function, if it is a generator.
108 pub yield_ty: Option<Ty<'tcx>>,
110 /// Generator drop glue.
111 pub generator_drop: Option<Box<BodyCache<'tcx>>>,
113 /// The layout of a generator. Produced by the state transformation.
114 pub generator_layout: Option<GeneratorLayout<'tcx>>,
116 /// If this is a generator then record the type of source expression that caused this generator
118 pub generator_kind: Option<GeneratorKind>,
120 /// Declarations of locals.
122 /// The first local is the return value pointer, followed by `arg_count`
123 /// locals for the function arguments, followed by any user-declared
124 /// variables and temporaries.
125 pub local_decls: LocalDecls<'tcx>,
127 /// User type annotations.
128 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
130 /// The number of arguments this function takes.
132 /// Starting at local 1, `arg_count` locals will be provided by the caller
133 /// and can be assumed to be initialized.
135 /// If this MIR was built for a constant, this will be 0.
136 pub arg_count: usize,
138 /// Mark an argument local (which must be a tuple) as getting passed as
139 /// its individual components at the LLVM level.
141 /// This is used for the "rust-call" ABI.
142 pub spread_arg: Option<Local>,
144 /// Debug information pertaining to user variables, including captures.
145 pub var_debug_info: Vec<VarDebugInfo<'tcx>>,
147 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
148 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
149 /// this conversion from happening and use short circuiting, we will cause the following code
150 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
152 /// List of places where control flow was destroyed. Used for error reporting.
153 pub control_flow_destroyed: Vec<(Span, String)>,
155 /// A span representing this MIR, for error reporting.
159 impl<'tcx> Body<'tcx> {
161 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
162 source_scopes: IndexVec<SourceScope, SourceScopeData>,
163 local_decls: LocalDecls<'tcx>,
164 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
166 var_debug_info: Vec<VarDebugInfo<'tcx>>,
168 control_flow_destroyed: Vec<(Span, String)>,
169 generator_kind : Option<GeneratorKind>,
171 // We need `arg_count` locals, and one for the return place.
173 local_decls.len() >= arg_count + 1,
174 "expected at least {} locals, got {}",
180 phase: MirPhase::Build,
184 generator_drop: None,
185 generator_layout: None,
188 user_type_annotations,
193 control_flow_destroyed,
198 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
202 /// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
204 pub fn is_cfg_cyclic(&self) -> bool {
205 graph::is_cyclic(self)
209 pub fn local_kind(&self, local: Local) -> LocalKind {
210 let index = local.as_usize();
213 self.local_decls[local].mutability == Mutability::Mut,
214 "return place should be mutable"
217 LocalKind::ReturnPointer
218 } else if index < self.arg_count + 1 {
220 } else if self.local_decls[local].is_user_variable() {
227 /// Returns an iterator over all temporaries.
229 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
230 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
231 let local = Local::new(index);
232 if self.local_decls[local].is_user_variable() {
240 /// Returns an iterator over all user-declared locals.
242 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
243 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
244 let local = Local::new(index);
245 self.local_decls[local].is_user_variable().then_some(local)
249 /// Returns an iterator over all user-declared mutable locals.
251 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
252 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
253 let local = Local::new(index);
254 let decl = &self.local_decls[local];
255 if decl.is_user_variable() && decl.mutability == Mutability::Mut {
263 /// Returns an iterator over all user-declared mutable arguments and locals.
265 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
266 (1..self.local_decls.len()).filter_map(move |index| {
267 let local = Local::new(index);
268 let decl = &self.local_decls[local];
269 if (decl.is_user_variable() || index < self.arg_count + 1)
270 && decl.mutability == Mutability::Mut
279 /// Returns an iterator over all function arguments.
281 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
282 let arg_count = self.arg_count;
283 (1..=arg_count).map(Local::new)
286 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
287 /// locals that are neither arguments nor the return place).
289 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
290 let arg_count = self.arg_count;
291 let local_count = self.local_decls.len();
292 (arg_count + 1..local_count).map(Local::new)
295 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
296 /// invalidating statement indices in `Location`s.
297 pub fn make_statement_nop(&mut self, location: Location) {
298 let block = &mut self.basic_blocks[location.block];
299 debug_assert!(location.statement_index < block.statements.len());
300 block.statements[location.statement_index].make_nop()
303 /// Returns the source info associated with `location`.
304 pub fn source_info(&self, location: Location) -> &SourceInfo {
305 let block = &self[location.block];
306 let stmts = &block.statements;
307 let idx = location.statement_index;
308 if idx < stmts.len() {
309 &stmts[idx].source_info
311 assert_eq!(idx, stmts.len());
312 &block.terminator().source_info
316 /// Checks if `sub` is a sub scope of `sup`
317 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
319 match self.source_scopes[sub].parent_scope {
320 None => return false,
327 /// Returns the return type; it always return first element from `local_decls` array.
328 pub fn return_ty(&self) -> Ty<'tcx> {
329 self.local_decls[RETURN_PLACE].ty
332 /// Gets the location of the terminator for the given block.
333 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
334 Location { block: bb, statement_index: self[bb].statements.len() }
338 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
341 /// Unsafe because of a PushUnsafeBlock
343 /// Unsafe because of an unsafe fn
345 /// Unsafe because of an `unsafe` block
346 ExplicitUnsafe(hir::HirId),
349 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
350 type Output = BasicBlockData<'tcx>;
353 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
354 &self.basic_blocks()[index]
358 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
359 pub enum ClearCrossCrate<T> {
364 impl<T> ClearCrossCrate<T> {
365 pub fn as_ref(&'a self) -> ClearCrossCrate<&'a T> {
367 ClearCrossCrate::Clear => ClearCrossCrate::Clear,
368 ClearCrossCrate::Set(v) => ClearCrossCrate::Set(v),
372 pub fn assert_crate_local(self) -> T {
374 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
375 ClearCrossCrate::Set(v) => v,
380 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
381 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
383 /// Grouped information about the source code origin of a MIR entity.
384 /// Intended to be inspected by diagnostics and debuginfo.
385 /// Most passes can work with it as a whole, within a single function.
386 // The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
387 // `Hash`. Please ping @bjorn3 if removing them.
388 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
389 pub struct SourceInfo {
390 /// The source span for the AST pertaining to this MIR entity.
393 /// The source scope, keeping track of which bindings can be
394 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
395 pub scope: SourceScope,
398 ///////////////////////////////////////////////////////////////////////////
399 // Mutability and borrow kinds
401 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
402 pub enum Mutability {
407 impl From<Mutability> for hir::Mutability {
408 fn from(m: Mutability) -> Self {
410 Mutability::Mut => hir::Mutability::Mutable,
411 Mutability::Not => hir::Mutability::Immutable,
417 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
419 pub enum BorrowKind {
420 /// Data must be immutable and is aliasable.
423 /// The immediately borrowed place must be immutable, but projections from
424 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
425 /// conflict with a mutable borrow of `a.b.c`.
427 /// This is used when lowering matches: when matching on a place we want to
428 /// ensure that place have the same value from the start of the match until
429 /// an arm is selected. This prevents this code from compiling:
431 /// let mut x = &Some(0);
434 /// Some(_) if { x = &None; false } => (),
438 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
439 /// should not prevent `if let None = x { ... }`, for example, because the
440 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
441 /// We can also report errors with this kind of borrow differently.
444 /// Data must be immutable but not aliasable. This kind of borrow
445 /// cannot currently be expressed by the user and is used only in
446 /// implicit closure bindings. It is needed when the closure is
447 /// borrowing or mutating a mutable referent, e.g.:
449 /// let x: &mut isize = ...;
450 /// let y = || *x += 5;
452 /// If we were to try to translate this closure into a more explicit
453 /// form, we'd encounter an error with the code as written:
455 /// struct Env { x: & &mut isize }
456 /// let x: &mut isize = ...;
457 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
458 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
460 /// This is then illegal because you cannot mutate an `&mut` found
461 /// in an aliasable location. To solve, you'd have to translate with
462 /// an `&mut` borrow:
464 /// struct Env { x: & &mut isize }
465 /// let x: &mut isize = ...;
466 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
467 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
469 /// Now the assignment to `**env.x` is legal, but creating a
470 /// mutable pointer to `x` is not because `x` is not mutable. We
471 /// could fix this by declaring `x` as `let mut x`. This is ok in
472 /// user code, if awkward, but extra weird for closures, since the
473 /// borrow is hidden.
475 /// So we introduce a "unique imm" borrow -- the referent is
476 /// immutable, but not aliasable. This solves the problem. For
477 /// simplicity, we don't give users the way to express this
478 /// borrow, it's just used when translating closures.
481 /// Data is mutable and not aliasable.
483 /// `true` if this borrow arose from method-call auto-ref
484 /// (i.e., `adjustment::Adjust::Borrow`).
485 allow_two_phase_borrow: bool,
490 pub fn allows_two_phase_borrow(&self) -> bool {
492 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
493 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
498 ///////////////////////////////////////////////////////////////////////////
499 // Variables and temps
501 rustc_index::newtype_index! {
504 DEBUG_FORMAT = "_{}",
505 const RETURN_PLACE = 0,
509 impl Atom for Local {
510 fn index(self) -> usize {
515 /// Classifies locals into categories. See `Body::local_kind`.
516 #[derive(PartialEq, Eq, Debug, HashStable)]
518 /// User-declared variable binding.
520 /// Compiler-introduced temporary.
522 /// Function argument.
524 /// Location of function's return value.
528 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
529 pub struct VarBindingForm<'tcx> {
530 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
531 pub binding_mode: ty::BindingMode,
532 /// If an explicit type was provided for this variable binding,
533 /// this holds the source Span of that type.
535 /// NOTE: if you want to change this to a `HirId`, be wary that
536 /// doing so breaks incremental compilation (as of this writing),
537 /// while a `Span` does not cause our tests to fail.
538 pub opt_ty_info: Option<Span>,
539 /// Place of the RHS of the =, or the subject of the `match` where this
540 /// variable is initialized. None in the case of `let PATTERN;`.
541 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
542 /// (a) the right-hand side isn't evaluated as a place expression.
543 /// (b) it gives a way to separate this case from the remaining cases
545 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
546 /// The span of the pattern in which this variable was bound.
550 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
551 pub enum BindingForm<'tcx> {
552 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
553 Var(VarBindingForm<'tcx>),
554 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
555 ImplicitSelf(ImplicitSelfKind),
556 /// Reference used in a guard expression to ensure immutability.
560 /// Represents what type of implicit self a function has, if any.
561 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
562 pub enum ImplicitSelfKind {
563 /// Represents a `fn x(self);`.
565 /// Represents a `fn x(mut self);`.
567 /// Represents a `fn x(&self);`.
569 /// Represents a `fn x(&mut self);`.
571 /// Represents when a function does not have a self argument or
572 /// when a function has a `self: X` argument.
576 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
578 mod binding_form_impl {
579 use crate::ich::StableHashingContext;
580 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
582 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
583 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
584 use super::BindingForm::*;
585 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
588 Var(binding) => binding.hash_stable(hcx, hasher),
589 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
596 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
597 /// created during evaluation of expressions in a block tail
598 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
600 /// It is used to improve diagnostics when such temporaries are
601 /// involved in borrow_check errors, e.g., explanations of where the
602 /// temporaries come from, when their destructors are run, and/or how
603 /// one might revise the code to satisfy the borrow checker's rules.
604 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
605 pub struct BlockTailInfo {
606 /// If `true`, then the value resulting from evaluating this tail
607 /// expression is ignored by the block's expression context.
609 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
610 /// but not e.g., `let _x = { ...; tail };`
611 pub tail_result_is_ignored: bool,
616 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
617 /// argument, or the return place.
618 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
619 pub struct LocalDecl<'tcx> {
620 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
622 /// Temporaries and the return place are always mutable.
623 pub mutability: Mutability,
625 // FIXME(matthewjasper) Don't store in this in `Body`
626 pub local_info: LocalInfo<'tcx>,
628 /// `true` if this is an internal local.
630 /// These locals are not based on types in the source code and are only used
631 /// for a few desugarings at the moment.
633 /// The generator transformation will sanity check the locals which are live
634 /// across a suspension point against the type components of the generator
635 /// which type checking knows are live across a suspension point. We need to
636 /// flag drop flags to avoid triggering this check as they are introduced
639 /// Unsafety checking will also ignore dereferences of these locals,
640 /// so they can be used for raw pointers only used in a desugaring.
642 /// This should be sound because the drop flags are fully algebraic, and
643 /// therefore don't affect the OIBIT or outlives properties of the
647 /// If this local is a temporary and `is_block_tail` is `Some`,
648 /// then it is a temporary created for evaluation of some
649 /// subexpression of some block's tail expression (with no
650 /// intervening statement context).
651 // FIXME(matthewjasper) Don't store in this in `Body`
652 pub is_block_tail: Option<BlockTailInfo>,
654 /// The type of this local.
657 /// If the user manually ascribed a type to this variable,
658 /// e.g., via `let x: T`, then we carry that type here. The MIR
659 /// borrow checker needs this information since it can affect
660 /// region inference.
661 // FIXME(matthewjasper) Don't store in this in `Body`
662 pub user_ty: UserTypeProjections,
664 /// The *syntactic* (i.e., not visibility) source scope the local is defined
665 /// in. If the local was defined in a let-statement, this
666 /// is *within* the let-statement, rather than outside
669 /// This is needed because the visibility source scope of locals within
670 /// a let-statement is weird.
672 /// The reason is that we want the local to be *within* the let-statement
673 /// for lint purposes, but we want the local to be *after* the let-statement
674 /// for names-in-scope purposes.
676 /// That's it, if we have a let-statement like the one in this
680 /// fn foo(x: &str) {
681 /// #[allow(unused_mut)]
682 /// let mut x: u32 = { // <- one unused mut
683 /// let mut y: u32 = x.parse().unwrap();
690 /// Then, from a lint point of view, the declaration of `x: u32`
691 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
692 /// lint scopes are the same as the AST/HIR nesting.
694 /// However, from a name lookup point of view, the scopes look more like
695 /// as if the let-statements were `match` expressions:
698 /// fn foo(x: &str) {
700 /// match x.parse().unwrap() {
709 /// We care about the name-lookup scopes for debuginfo - if the
710 /// debuginfo instruction pointer is at the call to `x.parse()`, we
711 /// want `x` to refer to `x: &str`, but if it is at the call to
712 /// `drop(x)`, we want it to refer to `x: u32`.
714 /// To allow both uses to work, we need to have more than a single scope
715 /// for a local. We have the `source_info.scope` represent the "syntactic"
716 /// lint scope (with a variable being under its let block) while the
717 /// `var_debug_info.source_info.scope` represents the "local variable"
718 /// scope (where the "rest" of a block is under all prior let-statements).
720 /// The end result looks like this:
724 /// │{ argument x: &str }
726 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
727 /// │ │ // in practice because I'm lazy.
729 /// │ │← x.source_info.scope
730 /// │ │← `x.parse().unwrap()`
732 /// │ │ │← y.source_info.scope
734 /// │ │ │{ let y: u32 }
736 /// │ │ │← y.var_debug_info.source_info.scope
739 /// │ │{ let x: u32 }
740 /// │ │← x.var_debug_info.source_info.scope
741 /// │ │← `drop(x)` // This accesses `x: u32`.
743 pub source_info: SourceInfo,
746 /// Extra information about a local that's used for diagnostics.
747 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
748 pub enum LocalInfo<'tcx> {
749 /// A user-defined local variable or function parameter
751 /// The `BindingForm` is solely used for local diagnostics when generating
752 /// warnings/errors when compiling the current crate, and therefore it need
753 /// not be visible across crates.
754 User(ClearCrossCrate<BindingForm<'tcx>>),
755 /// A temporary created that references the static with the given `DefId`.
756 StaticRef { def_id: DefId, is_thread_local: bool },
757 /// Any other temporary, the return place, or an anonymous function parameter.
761 impl<'tcx> LocalDecl<'tcx> {
762 /// Returns `true` only if local is a binding that can itself be
763 /// made mutable via the addition of the `mut` keyword, namely
764 /// something like the occurrences of `x` in:
765 /// - `fn foo(x: Type) { ... }`,
767 /// - or `match ... { C(x) => ... }`
768 pub fn can_be_made_mutable(&self) -> bool {
769 match self.local_info {
770 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
771 binding_mode: ty::BindingMode::BindByValue(_),
778 ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)),
785 /// Returns `true` if local is definitely not a `ref ident` or
786 /// `ref mut ident` binding. (Such bindings cannot be made into
787 /// mutable bindings, but the inverse does not necessarily hold).
788 pub fn is_nonref_binding(&self) -> bool {
789 match self.local_info {
790 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
791 binding_mode: ty::BindingMode::BindByValue(_),
797 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
803 /// Returns `true` if this variable is a named variable or function
804 /// parameter declared by the user.
806 pub fn is_user_variable(&self) -> bool {
807 match self.local_info {
808 LocalInfo::User(_) => true,
813 /// Returns `true` if this is a reference to a variable bound in a `match`
814 /// expression that is used to access said variable for the guard of the
816 pub fn is_ref_for_guard(&self) -> bool {
817 match self.local_info {
818 LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
823 /// Returns `Some` if this is a reference to a static item that is used to
824 /// access that static
825 pub fn is_ref_to_static(&self) -> bool {
826 match self.local_info {
827 LocalInfo::StaticRef { .. } => true,
832 /// Returns `Some` if this is a reference to a static item that is used to
833 /// access that static
834 pub fn is_ref_to_thread_local(&self) -> bool {
835 match self.local_info {
836 LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
841 /// Returns `true` is the local is from a compiler desugaring, e.g.,
842 /// `__next` from a `for` loop.
844 pub fn from_compiler_desugaring(&self) -> bool {
845 self.source_info.span.desugaring_kind().is_some()
848 /// Creates a new `LocalDecl` for a temporary.
850 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
851 Self::new_local(ty, Mutability::Mut, false, span)
854 /// Converts `self` into same `LocalDecl` except tagged as immutable.
856 pub fn immutable(mut self) -> Self {
857 self.mutability = Mutability::Not;
861 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
863 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
864 assert!(self.is_block_tail.is_none());
865 self.is_block_tail = Some(info);
869 /// Creates a new `LocalDecl` for a internal temporary.
871 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
872 Self::new_local(ty, Mutability::Mut, true, span)
876 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
880 user_ty: UserTypeProjections::none(),
881 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
883 local_info: LocalInfo::Other,
888 /// Builds a `LocalDecl` for the return place.
890 /// This must be inserted into the `local_decls` list as the first local.
892 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
894 mutability: Mutability::Mut,
896 user_ty: UserTypeProjections::none(),
897 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
900 local_info: LocalInfo::Other,
905 /// Debug information pertaining to a user variable.
906 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
907 pub struct VarDebugInfo<'tcx> {
910 /// Source info of the user variable, including the scope
911 /// within which the variable is visible (to debuginfo)
912 /// (see `LocalDecl`'s `source_info` field for more details).
913 pub source_info: SourceInfo,
915 /// Where the data for this user variable is to be found.
916 /// NOTE(eddyb) There's an unenforced invariant that this `Place` is
917 /// based on a `Local`, not a `Static`, and contains no indexing.
918 pub place: Place<'tcx>,
921 ///////////////////////////////////////////////////////////////////////////
924 rustc_index::newtype_index! {
925 pub struct BasicBlock {
927 DEBUG_FORMAT = "bb{}",
928 const START_BLOCK = 0,
933 pub fn start_location(self) -> Location {
934 Location { block: self, statement_index: 0 }
938 ///////////////////////////////////////////////////////////////////////////
939 // BasicBlockData and Terminator
941 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
942 pub struct BasicBlockData<'tcx> {
943 /// List of statements in this block.
944 pub statements: Vec<Statement<'tcx>>,
946 /// Terminator for this block.
948 /// N.B., this should generally ONLY be `None` during construction.
949 /// Therefore, you should generally access it via the
950 /// `terminator()` or `terminator_mut()` methods. The only
951 /// exception is that certain passes, such as `simplify_cfg`, swap
952 /// out the terminator temporarily with `None` while they continue
953 /// to recurse over the set of basic blocks.
954 pub terminator: Option<Terminator<'tcx>>,
956 /// If true, this block lies on an unwind path. This is used
957 /// during codegen where distinct kinds of basic blocks may be
958 /// generated (particularly for MSVC cleanup). Unwind blocks must
959 /// only branch to other unwind blocks.
960 pub is_cleanup: bool,
963 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
964 pub struct Terminator<'tcx> {
965 pub source_info: SourceInfo,
966 pub kind: TerminatorKind<'tcx>,
969 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
970 pub enum TerminatorKind<'tcx> {
971 /// Block should have one successor in the graph; we jump there.
972 Goto { target: BasicBlock },
974 /// Operand evaluates to an integer; jump depending on its value
975 /// to one of the targets, and otherwise fallback to `otherwise`.
977 /// The discriminant value being tested.
978 discr: Operand<'tcx>,
980 /// The type of value being tested.
983 /// Possible values. The locations to branch to in each case
984 /// are found in the corresponding indices from the `targets` vector.
985 values: Cow<'tcx, [u128]>,
987 /// Possible branch sites. The last element of this vector is used
988 /// for the otherwise branch, so targets.len() == values.len() + 1
991 // This invariant is quite non-obvious and also could be improved.
992 // One way to make this invariant is to have something like this instead:
994 // branches: Vec<(ConstInt, BasicBlock)>,
995 // otherwise: Option<BasicBlock> // exhaustive if None
997 // However we’ve decided to keep this as-is until we figure a case
998 // where some other approach seems to be strictly better than other.
999 targets: Vec<BasicBlock>,
1002 /// Indicates that the landing pad is finished and unwinding should
1003 /// continue. Emitted by `build::scope::diverge_cleanup`.
1006 /// Indicates that the landing pad is finished and that the process
1007 /// should abort. Used to prevent unwinding for foreign items.
1010 /// Indicates a normal return. The return place should have
1011 /// been filled in by now. This should occur at most once.
1014 /// Indicates a terminator that can never be reached.
1017 /// Drop the `Place`.
1018 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1020 /// Drop the `Place` and assign the new value over it. This ensures
1021 /// that the assignment to `P` occurs *even if* the destructor for
1022 /// place unwinds. Its semantics are best explained by the
1027 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1035 /// Drop(P, goto BB1, unwind BB2)
1038 /// // P is now uninitialized
1042 /// // P is now uninitialized -- its dtor panicked
1047 location: Place<'tcx>,
1048 value: Operand<'tcx>,
1050 unwind: Option<BasicBlock>,
1053 /// Block ends with a call of a converging function.
1055 /// The function that’s being called.
1056 func: Operand<'tcx>,
1057 /// Arguments the function is called with.
1058 /// These are owned by the callee, which is free to modify them.
1059 /// This allows the memory occupied by "by-value" arguments to be
1060 /// reused across function calls without duplicating the contents.
1061 args: Vec<Operand<'tcx>>,
1062 /// Destination for the return value. If some, the call is converging.
1063 destination: Option<(Place<'tcx>, BasicBlock)>,
1064 /// Cleanups to be done if the call unwinds.
1065 cleanup: Option<BasicBlock>,
1066 /// `true` if this is from a call in HIR rather than from an overloaded
1067 /// operator. True for overloaded function call.
1068 from_hir_call: bool,
1071 /// Jump to the target if the condition has the expected value,
1072 /// otherwise panic with a message and a cleanup target.
1074 cond: Operand<'tcx>,
1076 msg: AssertMessage<'tcx>,
1078 cleanup: Option<BasicBlock>,
1081 /// A suspend point.
1083 /// The value to return.
1084 value: Operand<'tcx>,
1085 /// Where to resume to.
1087 /// Cleanup to be done if the generator is dropped at this suspend point.
1088 drop: Option<BasicBlock>,
1091 /// Indicates the end of the dropping of a generator.
1094 /// A block where control flow only ever takes one real path, but borrowck
1095 /// needs to be more conservative.
1097 /// The target normal control flow will take.
1098 real_target: BasicBlock,
1099 /// A block control flow could conceptually jump to, but won't in
1101 imaginary_target: BasicBlock,
1103 /// A terminator for blocks that only take one path in reality, but where we
1104 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1105 /// This can arise in infinite loops with no function calls for example.
1107 /// The target normal control flow will take.
1108 real_target: BasicBlock,
1109 /// The imaginary cleanup block link. This particular path will never be taken
1110 /// in practice, but in order to avoid fragility we want to always
1111 /// consider it in borrowck. We don't want to accept programs which
1112 /// pass borrowck only when `panic=abort` or some assertions are disabled
1113 /// due to release vs. debug mode builds. This needs to be an `Option` because
1114 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1115 unwind: Option<BasicBlock>,
1119 pub type Successors<'a> =
1120 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1121 pub type SuccessorsMut<'a> =
1122 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1124 impl<'tcx> Terminator<'tcx> {
1125 pub fn successors(&self) -> Successors<'_> {
1126 self.kind.successors()
1129 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1130 self.kind.successors_mut()
1133 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1137 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1138 self.kind.unwind_mut()
1142 impl<'tcx> TerminatorKind<'tcx> {
1145 cond: Operand<'tcx>,
1148 ) -> TerminatorKind<'tcx> {
1149 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1150 TerminatorKind::SwitchInt {
1152 switch_ty: tcx.types.bool,
1153 values: From::from(BOOL_SWITCH_FALSE),
1154 targets: vec![f, t],
1158 pub fn successors(&self) -> Successors<'_> {
1159 use self::TerminatorKind::*;
1166 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1167 Goto { target: ref t }
1168 | Call { destination: None, cleanup: Some(ref t), .. }
1169 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1170 | Yield { resume: ref t, drop: None, .. }
1171 | DropAndReplace { target: ref t, unwind: None, .. }
1172 | Drop { target: ref t, unwind: None, .. }
1173 | Assert { target: ref t, cleanup: None, .. }
1174 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1175 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1176 | Yield { resume: ref t, drop: Some(ref u), .. }
1177 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1178 | Drop { target: ref t, unwind: Some(ref u), .. }
1179 | Assert { target: ref t, cleanup: Some(ref u), .. }
1180 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1181 Some(t).into_iter().chain(slice::from_ref(u))
1183 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1184 FalseEdges { ref real_target, ref imaginary_target } => {
1185 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1190 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1191 use self::TerminatorKind::*;
1198 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1199 Goto { target: ref mut t }
1200 | Call { destination: None, cleanup: Some(ref mut t), .. }
1201 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1202 | Yield { resume: ref mut t, drop: None, .. }
1203 | DropAndReplace { target: ref mut t, unwind: None, .. }
1204 | Drop { target: ref mut t, unwind: None, .. }
1205 | Assert { target: ref mut t, cleanup: None, .. }
1206 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1207 Some(t).into_iter().chain(&mut [])
1209 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1210 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1211 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1212 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1213 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1214 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1215 Some(t).into_iter().chain(slice::from_mut(u))
1217 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1218 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1219 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1224 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1226 TerminatorKind::Goto { .. }
1227 | TerminatorKind::Resume
1228 | TerminatorKind::Abort
1229 | TerminatorKind::Return
1230 | TerminatorKind::Unreachable
1231 | TerminatorKind::GeneratorDrop
1232 | TerminatorKind::Yield { .. }
1233 | TerminatorKind::SwitchInt { .. }
1234 | TerminatorKind::FalseEdges { .. } => None,
1235 TerminatorKind::Call { cleanup: ref unwind, .. }
1236 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1237 | TerminatorKind::DropAndReplace { ref unwind, .. }
1238 | TerminatorKind::Drop { ref unwind, .. }
1239 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1243 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1245 TerminatorKind::Goto { .. }
1246 | TerminatorKind::Resume
1247 | TerminatorKind::Abort
1248 | TerminatorKind::Return
1249 | TerminatorKind::Unreachable
1250 | TerminatorKind::GeneratorDrop
1251 | TerminatorKind::Yield { .. }
1252 | TerminatorKind::SwitchInt { .. }
1253 | TerminatorKind::FalseEdges { .. } => None,
1254 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1255 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1256 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1257 | TerminatorKind::Drop { ref mut unwind, .. }
1258 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1263 impl<'tcx> BasicBlockData<'tcx> {
1264 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1265 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1268 /// Accessor for terminator.
1270 /// Terminator may not be None after construction of the basic block is complete. This accessor
1271 /// provides a convenience way to reach the terminator.
1272 pub fn terminator(&self) -> &Terminator<'tcx> {
1273 self.terminator.as_ref().expect("invalid terminator state")
1276 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1277 self.terminator.as_mut().expect("invalid terminator state")
1280 pub fn retain_statements<F>(&mut self, mut f: F)
1282 F: FnMut(&mut Statement<'_>) -> bool,
1284 for s in &mut self.statements {
1291 pub fn expand_statements<F, I>(&mut self, mut f: F)
1293 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1294 I: iter::TrustedLen<Item = Statement<'tcx>>,
1296 // Gather all the iterators we'll need to splice in, and their positions.
1297 let mut splices: Vec<(usize, I)> = vec![];
1298 let mut extra_stmts = 0;
1299 for (i, s) in self.statements.iter_mut().enumerate() {
1300 if let Some(mut new_stmts) = f(s) {
1301 if let Some(first) = new_stmts.next() {
1302 // We can already store the first new statement.
1305 // Save the other statements for optimized splicing.
1306 let remaining = new_stmts.size_hint().0;
1308 splices.push((i + 1 + extra_stmts, new_stmts));
1309 extra_stmts += remaining;
1317 // Splice in the new statements, from the end of the block.
1318 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1319 // where a range of elements ("gap") is left uninitialized, with
1320 // splicing adding new elements to the end of that gap and moving
1321 // existing elements from before the gap to the end of the gap.
1322 // For now, this is safe code, emulating a gap but initializing it.
1323 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1324 self.statements.resize(
1327 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1328 kind: StatementKind::Nop,
1331 for (splice_start, new_stmts) in splices.into_iter().rev() {
1332 let splice_end = splice_start + new_stmts.size_hint().0;
1333 while gap.end > splice_end {
1336 self.statements.swap(gap.start, gap.end);
1338 self.statements.splice(splice_start..splice_end, new_stmts);
1339 gap.end = splice_start;
1343 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1344 if index < self.statements.len() {
1345 &self.statements[index]
1352 impl<'tcx> Debug for TerminatorKind<'tcx> {
1353 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1354 self.fmt_head(fmt)?;
1355 let successor_count = self.successors().count();
1356 let labels = self.fmt_successor_labels();
1357 assert_eq!(successor_count, labels.len());
1359 match successor_count {
1362 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1365 write!(fmt, " -> [")?;
1366 for (i, target) in self.successors().enumerate() {
1370 write!(fmt, "{}: {:?}", labels[i], target)?;
1378 impl<'tcx> TerminatorKind<'tcx> {
1379 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1380 /// successor basic block, if any. The only information not included is the list of possible
1381 /// successors, which may be rendered differently between the text and the graphviz format.
1382 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1383 use self::TerminatorKind::*;
1385 Goto { .. } => write!(fmt, "goto"),
1386 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1387 Return => write!(fmt, "return"),
1388 GeneratorDrop => write!(fmt, "generator_drop"),
1389 Resume => write!(fmt, "resume"),
1390 Abort => write!(fmt, "abort"),
1391 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1392 Unreachable => write!(fmt, "unreachable"),
1393 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1394 DropAndReplace { ref location, ref value, .. } => {
1395 write!(fmt, "replace({:?} <- {:?})", location, value)
1397 Call { ref func, ref args, ref destination, .. } => {
1398 if let Some((ref destination, _)) = *destination {
1399 write!(fmt, "{:?} = ", destination)?;
1401 write!(fmt, "{:?}(", func)?;
1402 for (index, arg) in args.iter().enumerate() {
1406 write!(fmt, "{:?}", arg)?;
1410 Assert { ref cond, expected, ref msg, .. } => {
1411 write!(fmt, "assert(")?;
1415 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1417 FalseEdges { .. } => write!(fmt, "falseEdges"),
1418 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1422 /// Returns the list of labels for the edges to the successor basic blocks.
1423 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1424 use self::TerminatorKind::*;
1426 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1427 Goto { .. } => vec!["".into()],
1428 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1429 let param_env = ty::ParamEnv::empty();
1430 let switch_ty = tcx.lift(&switch_ty).unwrap();
1431 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1435 ty::Const::from_scalar(
1437 Scalar::from_uint(u, size).into(),
1443 .chain(iter::once("otherwise".into()))
1446 Call { destination: Some(_), cleanup: Some(_), .. } => {
1447 vec!["return".into(), "unwind".into()]
1449 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1450 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1451 Call { destination: None, cleanup: None, .. } => vec![],
1452 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1453 Yield { drop: None, .. } => vec!["resume".into()],
1454 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1455 vec!["return".into()]
1457 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1458 vec!["return".into(), "unwind".into()]
1460 Assert { cleanup: None, .. } => vec!["".into()],
1461 Assert { .. } => vec!["success".into(), "unwind".into()],
1462 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1463 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1464 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1469 ///////////////////////////////////////////////////////////////////////////
1472 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1473 pub struct Statement<'tcx> {
1474 pub source_info: SourceInfo,
1475 pub kind: StatementKind<'tcx>,
1478 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1479 #[cfg(target_arch = "x86_64")]
1480 static_assert_size!(Statement<'_>, 32);
1482 impl Statement<'_> {
1483 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1484 /// invalidating statement indices in `Location`s.
1485 pub fn make_nop(&mut self) {
1486 self.kind = StatementKind::Nop
1489 /// Changes a statement to a nop and returns the original statement.
1490 pub fn replace_nop(&mut self) -> Self {
1492 source_info: self.source_info,
1493 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1498 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1499 pub enum StatementKind<'tcx> {
1500 /// Write the RHS Rvalue to the LHS Place.
1501 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1503 /// This represents all the reading that a pattern match may do
1504 /// (e.g., inspecting constants and discriminant values), and the
1505 /// kind of pattern it comes from. This is in order to adapt potential
1506 /// error messages to these specific patterns.
1508 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1509 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1510 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1512 /// Write the discriminant for a variant to the enum Place.
1513 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1515 /// Start a live range for the storage of the local.
1518 /// End the current live range for the storage of the local.
1521 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1522 /// of `StatementKind` low.
1523 InlineAsm(Box<InlineAsm<'tcx>>),
1525 /// Retag references in the given place, ensuring they got fresh tags. This is
1526 /// part of the Stacked Borrows model. These statements are currently only interpreted
1527 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1528 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1529 /// for more details.
1530 Retag(RetagKind, Box<Place<'tcx>>),
1532 /// Encodes a user's type ascription. These need to be preserved
1533 /// intact so that NLL can respect them. For example:
1537 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1538 /// to the user-given type `T`. The effect depends on the specified variance:
1540 /// - `Covariant` -- requires that `T_y <: T`
1541 /// - `Contravariant` -- requires that `T_y :> T`
1542 /// - `Invariant` -- requires that `T_y == T`
1543 /// - `Bivariant` -- no effect
1544 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1546 /// No-op. Useful for deleting instructions without affecting statement indices.
1550 /// Describes what kind of retag is to be performed.
1551 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1552 pub enum RetagKind {
1553 /// The initial retag when entering a function.
1555 /// Retag preparing for a two-phase borrow.
1557 /// Retagging raw pointers.
1559 /// A "normal" retag.
1563 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1564 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable, PartialEq)]
1565 pub enum FakeReadCause {
1566 /// Inject a fake read of the borrowed input at the end of each guards
1569 /// This should ensure that you cannot change the variant for an enum while
1570 /// you are in the midst of matching on it.
1573 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1574 /// generate a read of x to check that it is initialized and safe.
1577 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1578 /// in a match guard to ensure that it's value hasn't change by the time
1579 /// we create the OutsideGuard version.
1582 /// Officially, the semantics of
1584 /// `let pattern = <expr>;`
1586 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1587 /// into the pattern.
1589 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1590 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1591 /// but in some cases it can affect the borrow checker, as in #53695.
1592 /// Therefore, we insert a "fake read" here to ensure that we get
1593 /// appropriate errors.
1596 /// If we have an index expression like
1598 /// (*x)[1][{ x = y; 4}]
1600 /// then the first bounds check is invalidated when we evaluate the second
1601 /// index expression. Thus we create a fake borrow of `x` across the second
1602 /// indexer, which will cause a borrow check error.
1606 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1607 pub struct InlineAsm<'tcx> {
1608 pub asm: hir::InlineAsmInner,
1609 pub outputs: Box<[Place<'tcx>]>,
1610 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1613 impl Debug for Statement<'_> {
1614 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1615 use self::StatementKind::*;
1617 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1618 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1619 Retag(ref kind, ref place) => write!(
1623 RetagKind::FnEntry => "[fn entry] ",
1624 RetagKind::TwoPhase => "[2phase] ",
1625 RetagKind::Raw => "[raw] ",
1626 RetagKind::Default => "",
1630 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1631 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1632 SetDiscriminant { ref place, variant_index } => {
1633 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1635 InlineAsm(ref asm) => {
1636 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1638 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1639 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1641 Nop => write!(fmt, "nop"),
1646 ///////////////////////////////////////////////////////////////////////////
1649 /// A path to a value; something that can be evaluated without
1650 /// changing or disturbing program state.
1652 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1654 pub struct Place<'tcx> {
1655 pub base: PlaceBase<'tcx>,
1657 /// projection out of a place (access a field, deref a pointer, etc)
1658 pub projection: &'tcx List<PlaceElem<'tcx>>,
1661 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1664 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1666 pub enum PlaceBase<'tcx> {
1670 /// static or static mut variable
1671 Static(Box<Static<'tcx>>),
1674 /// We store the normalized type to avoid requiring normalization when reading MIR
1675 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
1676 RustcEncodable, RustcDecodable, HashStable)]
1677 pub struct Static<'tcx> {
1679 pub kind: StaticKind<'tcx>,
1680 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1681 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1682 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1683 /// into the calling frame.
1688 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1690 pub enum StaticKind<'tcx> {
1691 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1692 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1693 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1694 Promoted(Promoted, SubstsRef<'tcx>),
1698 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1699 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1700 pub enum ProjectionElem<V, T> {
1705 /// These indices are generated by slice patterns. Easiest to explain
1709 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1710 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1711 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1712 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1715 /// index or -index (in Python terms), depending on from_end
1717 /// thing being indexed must be at least this long
1719 /// counting backwards from end?
1723 /// These indices are generated by slice patterns.
1725 /// slice[from:-to] in Python terms.
1731 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1732 /// this for ADTs with more than one variant. It may be better to
1733 /// just introduce it always, or always for enums.
1735 /// The included Symbol is the name of the variant, used for printing MIR.
1736 Downcast(Option<Symbol>, VariantIdx),
1739 impl<V, T> ProjectionElem<V, T> {
1740 /// Returns `true` if the target of this projection may refer to a different region of memory
1742 fn is_indirect(&self) -> bool {
1744 Self::Deref => true,
1748 | Self::ConstantIndex { .. }
1749 | Self::Subslice { .. }
1750 | Self::Downcast(_, _)
1756 /// Alias for projections as they appear in places, where the base is a place
1757 /// and the index is a local.
1758 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1760 impl<'tcx> Copy for PlaceElem<'tcx> { }
1762 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1763 #[cfg(target_arch = "x86_64")]
1764 static_assert_size!(PlaceElem<'_>, 16);
1766 /// Alias for projections as they appear in `UserTypeProjection`, where we
1767 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1768 pub type ProjectionKind = ProjectionElem<(), ()>;
1770 rustc_index::newtype_index! {
1773 DEBUG_FORMAT = "field[{}]"
1777 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1778 pub struct PlaceRef<'a, 'tcx> {
1779 pub base: &'a PlaceBase<'tcx>,
1780 pub projection: &'a [PlaceElem<'tcx>],
1783 impl<'tcx> Place<'tcx> {
1784 // FIXME change this to a const fn by also making List::empty a const fn.
1785 pub fn return_place() -> Place<'tcx> {
1787 base: PlaceBase::Local(RETURN_PLACE),
1788 projection: List::empty(),
1792 /// Returns `true` if this `Place` contains a `Deref` projection.
1794 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1795 /// same region of memory as its base.
1796 pub fn is_indirect(&self) -> bool {
1797 self.projection.iter().any(|elem| elem.is_indirect())
1800 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1801 /// a single deref of a local.
1803 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1804 pub fn local_or_deref_local(&self) -> Option<Local> {
1805 match self.as_ref() {
1807 base: &PlaceBase::Local(local),
1811 base: &PlaceBase::Local(local),
1812 projection: &[ProjectionElem::Deref],
1818 /// If this place represents a local variable like `_X` with no
1819 /// projections, return `Some(_X)`.
1820 pub fn as_local(&self) -> Option<Local> {
1821 self.as_ref().as_local()
1824 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1827 projection: &self.projection,
1832 impl From<Local> for Place<'_> {
1833 fn from(local: Local) -> Self {
1836 projection: List::empty(),
1841 impl From<Local> for PlaceBase<'_> {
1842 fn from(local: Local) -> Self {
1843 PlaceBase::Local(local)
1847 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1848 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1849 /// a single deref of a local.
1851 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1852 pub fn local_or_deref_local(&self) -> Option<Local> {
1855 base: PlaceBase::Local(local),
1859 base: PlaceBase::Local(local),
1860 projection: [ProjectionElem::Deref],
1866 /// If this place represents a local variable like `_X` with no
1867 /// projections, return `Some(_X)`.
1868 pub fn as_local(&self) -> Option<Local> {
1870 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1876 impl Debug for Place<'_> {
1877 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1878 for elem in self.projection.iter().rev() {
1880 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1881 write!(fmt, "(").unwrap();
1883 ProjectionElem::Deref => {
1884 write!(fmt, "(*").unwrap();
1886 ProjectionElem::Index(_)
1887 | ProjectionElem::ConstantIndex { .. }
1888 | ProjectionElem::Subslice { .. } => {}
1892 write!(fmt, "{:?}", self.base)?;
1894 for elem in self.projection.iter() {
1896 ProjectionElem::Downcast(Some(name), _index) => {
1897 write!(fmt, " as {})", name)?;
1899 ProjectionElem::Downcast(None, index) => {
1900 write!(fmt, " as variant#{:?})", index)?;
1902 ProjectionElem::Deref => {
1905 ProjectionElem::Field(field, ty) => {
1906 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1908 ProjectionElem::Index(ref index) => {
1909 write!(fmt, "[{:?}]", index)?;
1911 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1912 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1914 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1915 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1917 ProjectionElem::Subslice { from, to } if *to == 0 => {
1918 write!(fmt, "[{:?}:]", from)?;
1920 ProjectionElem::Subslice { from, to } if *from == 0 => {
1921 write!(fmt, "[:-{:?}]", to)?;
1923 ProjectionElem::Subslice { from, to } => {
1924 write!(fmt, "[{:?}:-{:?}]", from, to)?;
1933 impl Debug for PlaceBase<'_> {
1934 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1936 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
1937 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
1938 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
1940 PlaceBase::Static(box self::Static {
1941 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
1943 write!(fmt, "({:?}: {:?})", promoted, ty)
1949 ///////////////////////////////////////////////////////////////////////////
1952 rustc_index::newtype_index! {
1953 pub struct SourceScope {
1955 DEBUG_FORMAT = "scope[{}]",
1956 const OUTERMOST_SOURCE_SCOPE = 0,
1960 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1961 pub struct SourceScopeData {
1963 pub parent_scope: Option<SourceScope>,
1965 /// Crate-local information for this source scope, that can't (and
1966 /// needn't) be tracked across crates.
1967 pub local_data: ClearCrossCrate<SourceScopeLocalData>,
1970 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1971 pub struct SourceScopeLocalData {
1972 /// An `HirId` with lint levels equivalent to this scope's lint levels.
1973 pub lint_root: hir::HirId,
1974 /// The unsafe block that contains this node.
1978 ///////////////////////////////////////////////////////////////////////////
1981 /// These are values that can appear inside an rvalue. They are intentionally
1982 /// limited to prevent rvalues from being nested in one another.
1983 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
1984 pub enum Operand<'tcx> {
1985 /// Copy: The value must be available for use afterwards.
1987 /// This implies that the type of the place must be `Copy`; this is true
1988 /// by construction during build, but also checked by the MIR type checker.
1991 /// Move: The value (including old borrows of it) will not be used again.
1993 /// Safe for values of all types (modulo future developments towards `?Move`).
1994 /// Correct usage patterns are enforced by the borrow checker for safe code.
1995 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
1998 /// Synthesizes a constant value.
1999 Constant(Box<Constant<'tcx>>),
2002 impl<'tcx> Debug for Operand<'tcx> {
2003 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2004 use self::Operand::*;
2006 Constant(ref a) => write!(fmt, "{:?}", a),
2007 Copy(ref place) => write!(fmt, "{:?}", place),
2008 Move(ref place) => write!(fmt, "move {:?}", place),
2013 impl<'tcx> Operand<'tcx> {
2014 /// Convenience helper to make a constant that refers to the fn
2015 /// with given `DefId` and substs. Since this is used to synthesize
2016 /// MIR, assumes `user_ty` is None.
2017 pub fn function_handle(
2020 substs: SubstsRef<'tcx>,
2023 let ty = tcx.type_of(def_id).subst(tcx, substs);
2024 Operand::Constant(box Constant {
2027 literal: ty::Const::zero_sized(tcx, ty),
2031 pub fn to_copy(&self) -> Self {
2033 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2034 Operand::Move(ref place) => Operand::Copy(place.clone()),
2039 ///////////////////////////////////////////////////////////////////////////
2042 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2043 pub enum Rvalue<'tcx> {
2044 /// x (either a move or copy, depending on type of x)
2048 Repeat(Operand<'tcx>, u64),
2051 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2053 /// length of a [X] or [X;n] value
2056 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2058 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2059 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2061 NullaryOp(NullOp, Ty<'tcx>),
2062 UnaryOp(UnOp, Operand<'tcx>),
2064 /// Read the discriminant of an ADT.
2066 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2067 /// be defined to return, say, a 0) if ADT is not an enum.
2068 Discriminant(Place<'tcx>),
2070 /// Creates an aggregate value, like a tuple or struct. This is
2071 /// only needed because we want to distinguish `dest = Foo { x:
2072 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2073 /// that `Foo` has a destructor. These rvalues can be optimized
2074 /// away after type-checking and before lowering.
2075 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2078 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2081 Pointer(PointerCast),
2084 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2085 pub enum AggregateKind<'tcx> {
2086 /// The type is of the element
2090 /// The second field is the variant index. It's equal to 0 for struct
2091 /// and union expressions. The fourth field is
2092 /// active field number and is present only for union expressions
2093 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2094 /// active field index would identity the field `c`
2095 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2097 Closure(DefId, SubstsRef<'tcx>),
2098 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2101 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2103 /// The `+` operator (addition)
2105 /// The `-` operator (subtraction)
2107 /// The `*` operator (multiplication)
2109 /// The `/` operator (division)
2111 /// The `%` operator (modulus)
2113 /// The `^` operator (bitwise xor)
2115 /// The `&` operator (bitwise and)
2117 /// The `|` operator (bitwise or)
2119 /// The `<<` operator (shift left)
2121 /// The `>>` operator (shift right)
2123 /// The `==` operator (equality)
2125 /// The `<` operator (less than)
2127 /// The `<=` operator (less than or equal to)
2129 /// The `!=` operator (not equal to)
2131 /// The `>=` operator (greater than or equal to)
2133 /// The `>` operator (greater than)
2135 /// The `ptr.offset` operator
2140 pub fn is_checkable(self) -> bool {
2143 Add | Sub | Mul | Shl | Shr => true,
2149 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2151 /// Returns the size of a value of that type
2153 /// Creates a new uninitialized box for a value of that type
2157 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2159 /// The `!` operator for logical inversion
2161 /// The `-` operator for negation
2165 impl<'tcx> Debug for Rvalue<'tcx> {
2166 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2167 use self::Rvalue::*;
2170 Use(ref place) => write!(fmt, "{:?}", place),
2171 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2172 Len(ref a) => write!(fmt, "Len({:?})", a),
2173 Cast(ref kind, ref place, ref ty) => {
2174 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2176 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2177 CheckedBinaryOp(ref op, ref a, ref b) => {
2178 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2180 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2181 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2182 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2183 Ref(region, borrow_kind, ref place) => {
2184 let kind_str = match borrow_kind {
2185 BorrowKind::Shared => "",
2186 BorrowKind::Shallow => "shallow ",
2187 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2190 // When printing regions, add trailing space if necessary.
2191 let print_region = ty::tls::with(|tcx| {
2192 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2194 let region = if print_region {
2195 let mut region = region.to_string();
2196 if region.len() > 0 {
2201 // Do not even print 'static
2204 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2207 Aggregate(ref kind, ref places) => {
2208 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2209 let mut tuple_fmt = fmt.debug_tuple("");
2210 for place in places {
2211 tuple_fmt.field(place);
2217 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2219 AggregateKind::Tuple => match places.len() {
2220 0 => write!(fmt, "()"),
2221 1 => write!(fmt, "({:?},)", places[0]),
2222 _ => fmt_tuple(fmt, places),
2225 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2226 let variant_def = &adt_def.variants[variant];
2229 ty::tls::with(|tcx| {
2230 let substs = tcx.lift(&substs).expect("could not lift for printing");
2231 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2232 .print_def_path(variant_def.def_id, substs)?;
2236 match variant_def.ctor_kind {
2237 CtorKind::Const => Ok(()),
2238 CtorKind::Fn => fmt_tuple(fmt, places),
2239 CtorKind::Fictive => {
2240 let mut struct_fmt = fmt.debug_struct("");
2241 for (field, place) in variant_def.fields.iter().zip(places) {
2242 struct_fmt.field(&field.ident.as_str(), place);
2249 AggregateKind::Closure(def_id, substs) => ty::tls::with(|tcx| {
2250 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2251 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2252 let substs = tcx.lift(&substs).unwrap();
2255 tcx.def_path_str_with_substs(def_id, substs),
2258 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2260 let mut struct_fmt = fmt.debug_struct(&name);
2262 if let Some(upvars) = tcx.upvars(def_id) {
2263 for (&var_id, place) in upvars.keys().zip(places) {
2264 let var_name = tcx.hir().name(var_id);
2265 struct_fmt.field(&var_name.as_str(), place);
2271 write!(fmt, "[closure]")
2275 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2276 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2277 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2278 let mut struct_fmt = fmt.debug_struct(&name);
2280 if let Some(upvars) = tcx.upvars(def_id) {
2281 for (&var_id, place) in upvars.keys().zip(places) {
2282 let var_name = tcx.hir().name(var_id);
2283 struct_fmt.field(&var_name.as_str(), place);
2289 write!(fmt, "[generator]")
2298 ///////////////////////////////////////////////////////////////////////////
2301 /// Two constants are equal if they are the same constant. Note that
2302 /// this does not necessarily mean that they are "==" in Rust -- in
2303 /// particular one must be wary of `NaN`!
2305 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2306 pub struct Constant<'tcx> {
2309 /// Optional user-given type: for something like
2310 /// `collect::<Vec<_>>`, this would be present and would
2311 /// indicate that `Vec<_>` was explicitly specified.
2313 /// Needed for NLL to impose user-given type constraints.
2314 pub user_ty: Option<UserTypeAnnotationIndex>,
2316 pub literal: &'tcx ty::Const<'tcx>,
2319 impl Constant<'tcx> {
2320 pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
2321 match self.literal.val.try_to_scalar() {
2322 Some(Scalar::Ptr(ptr)) => match tcx.alloc_map.lock().get(ptr.alloc_id) {
2323 Some(GlobalAlloc::Static(def_id)) => Some(def_id),
2326 tcx.sess.delay_span_bug(
2327 DUMMY_SP, "MIR cannot contain dangling const pointers",
2337 /// A collection of projections into user types.
2339 /// They are projections because a binding can occur a part of a
2340 /// parent pattern that has been ascribed a type.
2342 /// Its a collection because there can be multiple type ascriptions on
2343 /// the path from the root of the pattern down to the binding itself.
2348 /// struct S<'a>((i32, &'a str), String);
2349 /// let S((_, w): (i32, &'static str), _): S = ...;
2350 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2351 /// // --------------------------------- ^ (2)
2354 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2355 /// ascribed the type `(i32, &'static str)`.
2357 /// The highlights labelled `(2)` show the whole pattern being
2358 /// ascribed the type `S`.
2360 /// In this example, when we descend to `w`, we will have built up the
2361 /// following two projected types:
2363 /// * base: `S`, projection: `(base.0).1`
2364 /// * base: `(i32, &'static str)`, projection: `base.1`
2366 /// The first will lead to the constraint `w: &'1 str` (for some
2367 /// inferred region `'1`). The second will lead to the constraint `w:
2369 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2370 pub struct UserTypeProjections {
2371 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2374 impl<'tcx> UserTypeProjections {
2375 pub fn none() -> Self {
2376 UserTypeProjections { contents: vec![] }
2379 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2380 UserTypeProjections { contents: projs.collect() }
2383 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2384 self.contents.iter()
2387 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2388 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2391 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2392 self.contents.push((user_ty.clone(), span));
2398 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2400 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2404 pub fn index(self) -> Self {
2405 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2408 pub fn subslice(self, from: u32, to: u32) -> Self {
2409 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2412 pub fn deref(self) -> Self {
2413 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2416 pub fn leaf(self, field: Field) -> Self {
2417 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2420 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2421 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2425 /// Encodes the effect of a user-supplied type annotation on the
2426 /// subcomponents of a pattern. The effect is determined by applying the
2427 /// given list of proejctions to some underlying base type. Often,
2428 /// the projection element list `projs` is empty, in which case this
2429 /// directly encodes a type in `base`. But in the case of complex patterns with
2430 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2431 /// in which case the `projs` vector is used.
2435 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2437 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2438 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2439 /// determined by finding the type of the `.0` field from `T`.
2440 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2441 pub struct UserTypeProjection {
2442 pub base: UserTypeAnnotationIndex,
2443 pub projs: Vec<ProjectionKind>,
2446 impl Copy for ProjectionKind {}
2448 impl UserTypeProjection {
2449 pub(crate) fn index(mut self) -> Self {
2450 self.projs.push(ProjectionElem::Index(()));
2454 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2455 self.projs.push(ProjectionElem::Subslice { from, to });
2459 pub(crate) fn deref(mut self) -> Self {
2460 self.projs.push(ProjectionElem::Deref);
2464 pub(crate) fn leaf(mut self, field: Field) -> Self {
2465 self.projs.push(ProjectionElem::Field(field, ()));
2469 pub(crate) fn variant(
2471 adt_def: &'tcx AdtDef,
2472 variant_index: VariantIdx,
2475 self.projs.push(ProjectionElem::Downcast(
2476 Some(adt_def.variants[variant_index].ident.name),
2479 self.projs.push(ProjectionElem::Field(field, ()));
2484 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2486 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2487 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2488 use crate::mir::ProjectionElem::*;
2490 let base = self.base.fold_with(folder);
2491 let projs: Vec<_> = self
2494 .map(|elem| match elem {
2496 Field(f, ()) => Field(f.clone(), ()),
2497 Index(()) => Index(()),
2498 elem => elem.clone(),
2502 UserTypeProjection { base, projs }
2505 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2506 self.base.visit_with(visitor)
2507 // Note: there's nothing in `self.proj` to visit.
2511 rustc_index::newtype_index! {
2512 pub struct Promoted {
2514 DEBUG_FORMAT = "promoted[{}]"
2518 impl<'tcx> Debug for Constant<'tcx> {
2519 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2520 write!(fmt, "{}", self)
2524 impl<'tcx> Display for Constant<'tcx> {
2525 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2526 write!(fmt, "const ")?;
2527 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2528 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2529 // detailed and just not '{pointer}'.
2530 if let ty::RawPtr(_) = self.literal.ty.kind {
2531 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2533 write!(fmt, "{}", self.literal)
2538 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2539 type Node = BasicBlock;
2542 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2543 fn num_nodes(&self) -> usize {
2544 self.basic_blocks.len()
2548 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2549 fn start_node(&self) -> Self::Node {
2554 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2558 ) -> <Self as GraphSuccessors<'_>>::Iter {
2559 self.basic_blocks[node].terminator().successors().cloned()
2563 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2564 type Item = BasicBlock;
2565 type Iter = iter::Cloned<Successors<'b>>;
2568 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2569 pub struct Location {
2570 /// The block that the location is within.
2571 pub block: BasicBlock,
2573 /// The location is the position of the start of the statement; or, if
2574 /// `statement_index` equals the number of statements, then the start of the
2576 pub statement_index: usize,
2579 impl fmt::Debug for Location {
2580 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2581 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2586 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2588 /// Returns the location immediately after this one within the enclosing block.
2590 /// Note that if this location represents a terminator, then the
2591 /// resulting location would be out of bounds and invalid.
2592 pub fn successor_within_block(&self) -> Location {
2593 Location { block: self.block, statement_index: self.statement_index + 1 }
2596 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2597 pub fn is_predecessor_of<'tcx>(
2600 body: ReadOnlyBodyCache<'_, 'tcx>
2602 // If we are in the same block as the other location and are an earlier statement
2603 // then we are a predecessor of `other`.
2604 if self.block == other.block && self.statement_index < other.statement_index {
2608 // If we're in another block, then we want to check that block is a predecessor of `other`.
2609 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).to_vec();
2610 let mut visited = FxHashSet::default();
2612 while let Some(block) = queue.pop() {
2613 // If we haven't visited this block before, then make sure we visit it's predecessors.
2614 if visited.insert(block) {
2615 queue.extend(body.predecessors_for(block).iter().cloned());
2620 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2621 // we found that block by looking at the predecessors of `other`).
2622 if self.block == block {
2630 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2631 if self.block == other.block {
2632 self.statement_index <= other.statement_index
2634 dominators.is_dominated_by(other.block, self.block)
2639 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2640 pub enum UnsafetyViolationKind {
2642 /// Permitted both in `const fn`s and regular `fn`s.
2644 BorrowPacked(hir::HirId),
2647 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2648 pub struct UnsafetyViolation {
2649 pub source_info: SourceInfo,
2650 pub description: Symbol,
2651 pub details: Symbol,
2652 pub kind: UnsafetyViolationKind,
2655 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2656 pub struct UnsafetyCheckResult {
2657 /// Violations that are propagated *upwards* from this function.
2658 pub violations: Lrc<[UnsafetyViolation]>,
2659 /// `unsafe` blocks in this function, along with whether they are used. This is
2660 /// used for the "unused_unsafe" lint.
2661 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2664 rustc_index::newtype_index! {
2665 pub struct GeneratorSavedLocal {
2667 DEBUG_FORMAT = "_{}",
2671 /// The layout of generator state.
2672 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2673 pub struct GeneratorLayout<'tcx> {
2674 /// The type of every local stored inside the generator.
2675 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2677 /// Which of the above fields are in each variant. Note that one field may
2678 /// be stored in multiple variants.
2679 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2681 /// Which saved locals are storage-live at the same time. Locals that do not
2682 /// have conflicts with each other are allowed to overlap in the computed
2684 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2687 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2688 pub struct BorrowCheckResult<'tcx> {
2689 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2690 pub used_mut_upvars: SmallVec<[Field; 8]>,
2693 /// The result of the `mir_const_qualif` query.
2695 /// Each field corresponds to an implementer of the `Qualif` trait in
2696 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2698 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2699 pub struct ConstQualifs {
2700 pub has_mut_interior: bool,
2701 pub needs_drop: bool,
2704 /// After we borrow check a closure, we are left with various
2705 /// requirements that we have inferred between the free regions that
2706 /// appear in the closure's signature or on its field types. These
2707 /// requirements are then verified and proved by the closure's
2708 /// creating function. This struct encodes those requirements.
2710 /// The requirements are listed as being between various
2711 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2712 /// vids refer to the free regions that appear in the closure (or
2713 /// generator's) type, in order of appearance. (This numbering is
2714 /// actually defined by the `UniversalRegions` struct in the NLL
2715 /// region checker. See for example
2716 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2717 /// regions in the closure's type "as if" they were erased, so their
2718 /// precise identity is not important, only their position.
2720 /// Example: If type check produces a closure with the closure substs:
2723 /// ClosureSubsts = [
2724 /// i8, // the "closure kind"
2725 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2726 /// &'a String, // some upvar
2730 /// here, there is one unique free region (`'a`) but it appears
2731 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2734 /// ClosureSubsts = [
2735 /// i8, // the "closure kind"
2736 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2737 /// &'2 String, // some upvar
2741 /// Now the code might impose a requirement like `'1: '2`. When an
2742 /// instance of the closure is created, the corresponding free regions
2743 /// can be extracted from its type and constrained to have the given
2744 /// outlives relationship.
2746 /// In some cases, we have to record outlives requirements between
2747 /// types and regions as well. In that case, if those types include
2748 /// any regions, those regions are recorded as `ReClosureBound`
2749 /// instances assigned one of these same indices. Those regions will
2750 /// be substituted away by the creator. We use `ReClosureBound` in
2751 /// that case because the regions must be allocated in the global
2752 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2753 /// internally within the rest of the NLL code).
2754 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2755 pub struct ClosureRegionRequirements<'tcx> {
2756 /// The number of external regions defined on the closure. In our
2757 /// example above, it would be 3 -- one for `'static`, then `'1`
2758 /// and `'2`. This is just used for a sanity check later on, to
2759 /// make sure that the number of regions we see at the callsite
2761 pub num_external_vids: usize,
2763 /// Requirements between the various free regions defined in
2765 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2768 /// Indicates an outlives-constraint between a type or between two
2769 /// free regions declared on the closure.
2770 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2771 pub struct ClosureOutlivesRequirement<'tcx> {
2772 // This region or type ...
2773 pub subject: ClosureOutlivesSubject<'tcx>,
2775 // ... must outlive this one.
2776 pub outlived_free_region: ty::RegionVid,
2778 // If not, report an error here ...
2779 pub blame_span: Span,
2781 // ... due to this reason.
2782 pub category: ConstraintCategory,
2785 /// Outlives-constraints can be categorized to determine whether and why they
2786 /// are interesting (for error reporting). Order of variants indicates sort
2787 /// order of the category, thereby influencing diagnostic output.
2789 /// See also [rustc_mir::borrow_check::nll::constraints].
2803 pub enum ConstraintCategory {
2811 /// A constraint that came from checking the body of a closure.
2813 /// We try to get the category that the closure used when reporting this.
2821 /// A "boring" constraint (caused by the given location) is one that
2822 /// the user probably doesn't want to see described in diagnostics,
2823 /// because it is kind of an artifact of the type system setup.
2824 /// Example: `x = Foo { field: y }` technically creates
2825 /// intermediate regions representing the "type of `Foo { field: y
2826 /// }`", and data flows from `y` into those variables, but they
2827 /// are not very interesting. The assignment into `x` on the other
2830 // Boring and applicable everywhere.
2833 /// A constraint that doesn't correspond to anything the user sees.
2837 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2838 /// that must outlive some region.
2839 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2840 pub enum ClosureOutlivesSubject<'tcx> {
2841 /// Subject is a type, typically a type parameter, but could also
2842 /// be a projection. Indicates a requirement like `T: 'a` being
2843 /// passed to the caller, where the type here is `T`.
2845 /// The type here is guaranteed not to contain any free regions at
2849 /// Subject is a free region from the closure. Indicates a requirement
2850 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2851 Region(ty::RegionVid),
2855 * `TypeFoldable` implementations for MIR types
2858 CloneTypeFoldableAndLiftImpls! {
2867 SourceScopeLocalData,
2868 UserTypeAnnotationIndex,
2871 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2872 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2873 use crate::mir::TerminatorKind::*;
2875 let kind = match self.kind {
2876 Goto { target } => Goto { target },
2877 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2878 discr: discr.fold_with(folder),
2879 switch_ty: switch_ty.fold_with(folder),
2880 values: values.clone(),
2881 targets: targets.clone(),
2883 Drop { ref location, target, unwind } => {
2884 Drop { location: location.fold_with(folder), target, unwind }
2886 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2887 location: location.fold_with(folder),
2888 value: value.fold_with(folder),
2892 Yield { ref value, resume, drop } => {
2893 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2895 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2897 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2900 func: func.fold_with(folder),
2901 args: args.fold_with(folder),
2907 Assert { ref cond, expected, ref msg, target, cleanup } => {
2909 let msg = match msg {
2910 BoundsCheck { ref len, ref index } =>
2912 len: len.fold_with(folder),
2913 index: index.fold_with(folder),
2915 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2916 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2919 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2921 GeneratorDrop => GeneratorDrop,
2925 Unreachable => Unreachable,
2926 FalseEdges { real_target, imaginary_target } => {
2927 FalseEdges { real_target, imaginary_target }
2929 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
2931 Terminator { source_info: self.source_info, kind }
2934 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2935 use crate::mir::TerminatorKind::*;
2938 SwitchInt { ref discr, switch_ty, .. } => {
2939 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
2941 Drop { ref location, .. } => location.visit_with(visitor),
2942 DropAndReplace { ref location, ref value, .. } => {
2943 location.visit_with(visitor) || value.visit_with(visitor)
2945 Yield { ref value, .. } => value.visit_with(visitor),
2946 Call { ref func, ref args, ref destination, .. } => {
2947 let dest = if let Some((ref loc, _)) = *destination {
2948 loc.visit_with(visitor)
2952 dest || func.visit_with(visitor) || args.visit_with(visitor)
2954 Assert { ref cond, ref msg, .. } => {
2955 if cond.visit_with(visitor) {
2958 BoundsCheck { ref len, ref index } =>
2959 len.visit_with(visitor) || index.visit_with(visitor),
2960 Panic { .. } | Overflow(_) | OverflowNeg |
2961 DivisionByZero | RemainderByZero |
2962 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2976 | FalseUnwind { .. } => false,
2981 impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
2982 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
2986 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
2991 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2992 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2994 base: self.base.fold_with(folder),
2995 projection: self.projection.fold_with(folder),
2999 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3000 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3004 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3005 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3007 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3008 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3012 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3014 PlaceBase::Local(local) => local.visit_with(visitor),
3015 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3020 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3021 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3022 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3023 folder.tcx().intern_place_elems(&v)
3026 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3027 self.iter().any(|t| t.visit_with(visitor))
3031 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3032 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3034 ty: self.ty.fold_with(folder),
3035 kind: self.kind.fold_with(folder),
3036 def_id: self.def_id,
3040 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3041 let Static { ty, kind, def_id: _ } = self;
3043 ty.visit_with(visitor) || kind.visit_with(visitor)
3047 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3048 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3050 StaticKind::Promoted(promoted, substs) =>
3051 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3052 StaticKind::Static => StaticKind::Static
3056 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3058 StaticKind::Promoted(promoted, substs) =>
3059 promoted.visit_with(visitor) || substs.visit_with(visitor),
3060 StaticKind::Static => { false }
3065 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3066 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3067 use crate::mir::Rvalue::*;
3069 Use(ref op) => Use(op.fold_with(folder)),
3070 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3071 Ref(region, bk, ref place) => {
3072 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3074 Len(ref place) => Len(place.fold_with(folder)),
3075 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3076 BinaryOp(op, ref rhs, ref lhs) => {
3077 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3079 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3080 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3082 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3083 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3084 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3085 Aggregate(ref kind, ref fields) => {
3086 let kind = box match **kind {
3087 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3088 AggregateKind::Tuple => AggregateKind::Tuple,
3089 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3092 substs.fold_with(folder),
3093 user_ty.fold_with(folder),
3096 AggregateKind::Closure(id, substs) => {
3097 AggregateKind::Closure(id, substs.fold_with(folder))
3099 AggregateKind::Generator(id, substs, movablity) => {
3100 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3103 Aggregate(kind, fields.fold_with(folder))
3108 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3109 use crate::mir::Rvalue::*;
3111 Use(ref op) => op.visit_with(visitor),
3112 Repeat(ref op, _) => op.visit_with(visitor),
3113 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3114 Len(ref place) => place.visit_with(visitor),
3115 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3116 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3117 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3119 UnaryOp(_, ref val) => val.visit_with(visitor),
3120 Discriminant(ref place) => place.visit_with(visitor),
3121 NullaryOp(_, ty) => ty.visit_with(visitor),
3122 Aggregate(ref kind, ref fields) => {
3124 AggregateKind::Array(ty) => ty.visit_with(visitor),
3125 AggregateKind::Tuple => false,
3126 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3127 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3129 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3130 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3131 }) || fields.visit_with(visitor)
3137 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3138 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3140 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3141 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3142 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3146 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3148 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3149 Operand::Constant(ref c) => c.visit_with(visitor),
3154 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3155 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3156 use crate::mir::ProjectionElem::*;
3160 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3161 Index(v) => Index(v.fold_with(folder)),
3162 elem => elem.clone(),
3166 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3167 use crate::mir::ProjectionElem::*;
3170 Field(_, ty) => ty.visit_with(visitor),
3171 Index(v) => v.visit_with(visitor),
3177 impl<'tcx> TypeFoldable<'tcx> for Field {
3178 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3181 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3186 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3187 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3190 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3195 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3196 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3199 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3204 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3205 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3207 span: self.span.clone(),
3208 user_ty: self.user_ty.fold_with(folder),
3209 literal: self.literal.fold_with(folder),
3212 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3213 self.literal.visit_with(visitor)