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 if self.local_decls[local].is_user_variable() {
253 /// Returns an iterator over all user-declared mutable locals.
255 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
256 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
257 let local = Local::new(index);
258 let decl = &self.local_decls[local];
259 if decl.is_user_variable() && decl.mutability == Mutability::Mut {
267 /// Returns an iterator over all user-declared mutable arguments and locals.
269 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
270 (1..self.local_decls.len()).filter_map(move |index| {
271 let local = Local::new(index);
272 let decl = &self.local_decls[local];
273 if (decl.is_user_variable() || index < self.arg_count + 1)
274 && decl.mutability == Mutability::Mut
283 /// Returns an iterator over all function arguments.
285 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
286 let arg_count = self.arg_count;
287 (1..=arg_count).map(Local::new)
290 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
291 /// locals that are neither arguments nor the return place).
293 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
294 let arg_count = self.arg_count;
295 let local_count = self.local_decls.len();
296 (arg_count + 1..local_count).map(Local::new)
299 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
300 /// invalidating statement indices in `Location`s.
301 pub fn make_statement_nop(&mut self, location: Location) {
302 let block = &mut self.basic_blocks[location.block];
303 debug_assert!(location.statement_index < block.statements.len());
304 block.statements[location.statement_index].make_nop()
307 /// Returns the source info associated with `location`.
308 pub fn source_info(&self, location: Location) -> &SourceInfo {
309 let block = &self[location.block];
310 let stmts = &block.statements;
311 let idx = location.statement_index;
312 if idx < stmts.len() {
313 &stmts[idx].source_info
315 assert_eq!(idx, stmts.len());
316 &block.terminator().source_info
320 /// Checks if `sub` is a sub scope of `sup`
321 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
323 match self.source_scopes[sub].parent_scope {
324 None => return false,
331 /// Returns the return type; it always return first element from `local_decls` array.
332 pub fn return_ty(&self) -> Ty<'tcx> {
333 self.local_decls[RETURN_PLACE].ty
336 /// Gets the location of the terminator for the given block.
337 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
338 Location { block: bb, statement_index: self[bb].statements.len() }
342 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
345 /// Unsafe because of a PushUnsafeBlock
347 /// Unsafe because of an unsafe fn
349 /// Unsafe because of an `unsafe` block
350 ExplicitUnsafe(hir::HirId),
353 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
354 type Output = BasicBlockData<'tcx>;
357 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
358 &self.basic_blocks()[index]
362 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
363 pub enum ClearCrossCrate<T> {
368 impl<T> ClearCrossCrate<T> {
369 pub fn as_ref(&'a self) -> ClearCrossCrate<&'a T> {
371 ClearCrossCrate::Clear => ClearCrossCrate::Clear,
372 ClearCrossCrate::Set(v) => ClearCrossCrate::Set(v),
376 pub fn assert_crate_local(self) -> T {
378 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
379 ClearCrossCrate::Set(v) => v,
384 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
385 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
387 /// Grouped information about the source code origin of a MIR entity.
388 /// Intended to be inspected by diagnostics and debuginfo.
389 /// Most passes can work with it as a whole, within a single function.
390 // The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
391 // `Hash`. Please ping @bjorn3 if removing them.
392 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
393 pub struct SourceInfo {
394 /// The source span for the AST pertaining to this MIR entity.
397 /// The source scope, keeping track of which bindings can be
398 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
399 pub scope: SourceScope,
402 ///////////////////////////////////////////////////////////////////////////
403 // Mutability and borrow kinds
405 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
406 pub enum Mutability {
411 impl From<Mutability> for hir::Mutability {
412 fn from(m: Mutability) -> Self {
414 Mutability::Mut => hir::Mutability::Mutable,
415 Mutability::Not => hir::Mutability::Immutable,
421 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
423 pub enum BorrowKind {
424 /// Data must be immutable and is aliasable.
427 /// The immediately borrowed place must be immutable, but projections from
428 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
429 /// conflict with a mutable borrow of `a.b.c`.
431 /// This is used when lowering matches: when matching on a place we want to
432 /// ensure that place have the same value from the start of the match until
433 /// an arm is selected. This prevents this code from compiling:
435 /// let mut x = &Some(0);
438 /// Some(_) if { x = &None; false } => (),
442 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
443 /// should not prevent `if let None = x { ... }`, for example, because the
444 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
445 /// We can also report errors with this kind of borrow differently.
448 /// Data must be immutable but not aliasable. This kind of borrow
449 /// cannot currently be expressed by the user and is used only in
450 /// implicit closure bindings. It is needed when the closure is
451 /// borrowing or mutating a mutable referent, e.g.:
453 /// let x: &mut isize = ...;
454 /// let y = || *x += 5;
456 /// If we were to try to translate this closure into a more explicit
457 /// form, we'd encounter an error with the code as written:
459 /// struct Env { x: & &mut isize }
460 /// let x: &mut isize = ...;
461 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
462 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
464 /// This is then illegal because you cannot mutate an `&mut` found
465 /// in an aliasable location. To solve, you'd have to translate with
466 /// an `&mut` borrow:
468 /// struct Env { x: & &mut isize }
469 /// let x: &mut isize = ...;
470 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
471 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
473 /// Now the assignment to `**env.x` is legal, but creating a
474 /// mutable pointer to `x` is not because `x` is not mutable. We
475 /// could fix this by declaring `x` as `let mut x`. This is ok in
476 /// user code, if awkward, but extra weird for closures, since the
477 /// borrow is hidden.
479 /// So we introduce a "unique imm" borrow -- the referent is
480 /// immutable, but not aliasable. This solves the problem. For
481 /// simplicity, we don't give users the way to express this
482 /// borrow, it's just used when translating closures.
485 /// Data is mutable and not aliasable.
487 /// `true` if this borrow arose from method-call auto-ref
488 /// (i.e., `adjustment::Adjust::Borrow`).
489 allow_two_phase_borrow: bool,
494 pub fn allows_two_phase_borrow(&self) -> bool {
496 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
497 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
502 ///////////////////////////////////////////////////////////////////////////
503 // Variables and temps
505 rustc_index::newtype_index! {
508 DEBUG_FORMAT = "_{}",
509 const RETURN_PLACE = 0,
513 impl Atom for Local {
514 fn index(self) -> usize {
519 /// Classifies locals into categories. See `Body::local_kind`.
520 #[derive(PartialEq, Eq, Debug, HashStable)]
522 /// User-declared variable binding.
524 /// Compiler-introduced temporary.
526 /// Function argument.
528 /// Location of function's return value.
532 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
533 pub struct VarBindingForm<'tcx> {
534 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
535 pub binding_mode: ty::BindingMode,
536 /// If an explicit type was provided for this variable binding,
537 /// this holds the source Span of that type.
539 /// NOTE: if you want to change this to a `HirId`, be wary that
540 /// doing so breaks incremental compilation (as of this writing),
541 /// while a `Span` does not cause our tests to fail.
542 pub opt_ty_info: Option<Span>,
543 /// Place of the RHS of the =, or the subject of the `match` where this
544 /// variable is initialized. None in the case of `let PATTERN;`.
545 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
546 /// (a) the right-hand side isn't evaluated as a place expression.
547 /// (b) it gives a way to separate this case from the remaining cases
549 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
550 /// The span of the pattern in which this variable was bound.
554 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
555 pub enum BindingForm<'tcx> {
556 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
557 Var(VarBindingForm<'tcx>),
558 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
559 ImplicitSelf(ImplicitSelfKind),
560 /// Reference used in a guard expression to ensure immutability.
564 /// Represents what type of implicit self a function has, if any.
565 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
566 pub enum ImplicitSelfKind {
567 /// Represents a `fn x(self);`.
569 /// Represents a `fn x(mut self);`.
571 /// Represents a `fn x(&self);`.
573 /// Represents a `fn x(&mut self);`.
575 /// Represents when a function does not have a self argument or
576 /// when a function has a `self: X` argument.
580 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
582 mod binding_form_impl {
583 use crate::ich::StableHashingContext;
584 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
586 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
587 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
588 use super::BindingForm::*;
589 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
592 Var(binding) => binding.hash_stable(hcx, hasher),
593 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
600 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
601 /// created during evaluation of expressions in a block tail
602 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
604 /// It is used to improve diagnostics when such temporaries are
605 /// involved in borrow_check errors, e.g., explanations of where the
606 /// temporaries come from, when their destructors are run, and/or how
607 /// one might revise the code to satisfy the borrow checker's rules.
608 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
609 pub struct BlockTailInfo {
610 /// If `true`, then the value resulting from evaluating this tail
611 /// expression is ignored by the block's expression context.
613 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
614 /// but not e.g., `let _x = { ...; tail };`
615 pub tail_result_is_ignored: bool,
620 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
621 /// argument, or the return place.
622 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
623 pub struct LocalDecl<'tcx> {
624 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
626 /// Temporaries and the return place are always mutable.
627 pub mutability: Mutability,
629 // FIXME(matthewjasper) Don't store in this in `Body`
630 pub local_info: LocalInfo<'tcx>,
632 /// `true` if this is an internal local.
634 /// These locals are not based on types in the source code and are only used
635 /// for a few desugarings at the moment.
637 /// The generator transformation will sanity check the locals which are live
638 /// across a suspension point against the type components of the generator
639 /// which type checking knows are live across a suspension point. We need to
640 /// flag drop flags to avoid triggering this check as they are introduced
643 /// Unsafety checking will also ignore dereferences of these locals,
644 /// so they can be used for raw pointers only used in a desugaring.
646 /// This should be sound because the drop flags are fully algebraic, and
647 /// therefore don't affect the OIBIT or outlives properties of the
651 /// If this local is a temporary and `is_block_tail` is `Some`,
652 /// then it is a temporary created for evaluation of some
653 /// subexpression of some block's tail expression (with no
654 /// intervening statement context).
655 // FIXME(matthewjasper) Don't store in this in `Body`
656 pub is_block_tail: Option<BlockTailInfo>,
658 /// The type of this local.
661 /// If the user manually ascribed a type to this variable,
662 /// e.g., via `let x: T`, then we carry that type here. The MIR
663 /// borrow checker needs this information since it can affect
664 /// region inference.
665 // FIXME(matthewjasper) Don't store in this in `Body`
666 pub user_ty: UserTypeProjections,
668 /// The *syntactic* (i.e., not visibility) source scope the local is defined
669 /// in. If the local was defined in a let-statement, this
670 /// is *within* the let-statement, rather than outside
673 /// This is needed because the visibility source scope of locals within
674 /// a let-statement is weird.
676 /// The reason is that we want the local to be *within* the let-statement
677 /// for lint purposes, but we want the local to be *after* the let-statement
678 /// for names-in-scope purposes.
680 /// That's it, if we have a let-statement like the one in this
684 /// fn foo(x: &str) {
685 /// #[allow(unused_mut)]
686 /// let mut x: u32 = { // <- one unused mut
687 /// let mut y: u32 = x.parse().unwrap();
694 /// Then, from a lint point of view, the declaration of `x: u32`
695 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
696 /// lint scopes are the same as the AST/HIR nesting.
698 /// However, from a name lookup point of view, the scopes look more like
699 /// as if the let-statements were `match` expressions:
702 /// fn foo(x: &str) {
704 /// match x.parse().unwrap() {
713 /// We care about the name-lookup scopes for debuginfo - if the
714 /// debuginfo instruction pointer is at the call to `x.parse()`, we
715 /// want `x` to refer to `x: &str`, but if it is at the call to
716 /// `drop(x)`, we want it to refer to `x: u32`.
718 /// To allow both uses to work, we need to have more than a single scope
719 /// for a local. We have the `source_info.scope` represent the "syntactic"
720 /// lint scope (with a variable being under its let block) while the
721 /// `var_debug_info.source_info.scope` represents the "local variable"
722 /// scope (where the "rest" of a block is under all prior let-statements).
724 /// The end result looks like this:
728 /// │{ argument x: &str }
730 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
731 /// │ │ // in practice because I'm lazy.
733 /// │ │← x.source_info.scope
734 /// │ │← `x.parse().unwrap()`
736 /// │ │ │← y.source_info.scope
738 /// │ │ │{ let y: u32 }
740 /// │ │ │← y.var_debug_info.source_info.scope
743 /// │ │{ let x: u32 }
744 /// │ │← x.var_debug_info.source_info.scope
745 /// │ │← `drop(x)` // This accesses `x: u32`.
747 pub source_info: SourceInfo,
750 /// Extra information about a local that's used for diagnostics.
751 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
752 pub enum LocalInfo<'tcx> {
753 /// A user-defined local variable or function parameter
755 /// The `BindingForm` is solely used for local diagnostics when generating
756 /// warnings/errors when compiling the current crate, and therefore it need
757 /// not be visible across crates.
758 User(ClearCrossCrate<BindingForm<'tcx>>),
759 /// A temporary created that references the static with the given `DefId`.
760 StaticRef { def_id: DefId, is_thread_local: bool },
761 /// Any other temporary, the return place, or an anonymous function parameter.
765 impl<'tcx> LocalDecl<'tcx> {
766 /// Returns `true` only if local is a binding that can itself be
767 /// made mutable via the addition of the `mut` keyword, namely
768 /// something like the occurrences of `x` in:
769 /// - `fn foo(x: Type) { ... }`,
771 /// - or `match ... { C(x) => ... }`
772 pub fn can_be_made_mutable(&self) -> bool {
773 match self.local_info {
774 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
775 binding_mode: ty::BindingMode::BindByValue(_),
782 ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)),
789 /// Returns `true` if local is definitely not a `ref ident` or
790 /// `ref mut ident` binding. (Such bindings cannot be made into
791 /// mutable bindings, but the inverse does not necessarily hold).
792 pub fn is_nonref_binding(&self) -> bool {
793 match self.local_info {
794 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
795 binding_mode: ty::BindingMode::BindByValue(_),
801 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
807 /// Returns `true` if this variable is a named variable or function
808 /// parameter declared by the user.
810 pub fn is_user_variable(&self) -> bool {
811 match self.local_info {
812 LocalInfo::User(_) => true,
817 /// Returns `true` if this is a reference to a variable bound in a `match`
818 /// expression that is used to access said variable for the guard of the
820 pub fn is_ref_for_guard(&self) -> bool {
821 match self.local_info {
822 LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
827 /// Returns `Some` if this is a reference to a static item that is used to
828 /// access that static
829 pub fn is_ref_to_static(&self) -> bool {
830 match self.local_info {
831 LocalInfo::StaticRef { .. } => true,
836 /// Returns `Some` if this is a reference to a static item that is used to
837 /// access that static
838 pub fn is_ref_to_thread_local(&self) -> bool {
839 match self.local_info {
840 LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
845 /// Returns `true` is the local is from a compiler desugaring, e.g.,
846 /// `__next` from a `for` loop.
848 pub fn from_compiler_desugaring(&self) -> bool {
849 self.source_info.span.desugaring_kind().is_some()
852 /// Creates a new `LocalDecl` for a temporary.
854 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
855 Self::new_local(ty, Mutability::Mut, false, span)
858 /// Converts `self` into same `LocalDecl` except tagged as immutable.
860 pub fn immutable(mut self) -> Self {
861 self.mutability = Mutability::Not;
865 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
867 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
868 assert!(self.is_block_tail.is_none());
869 self.is_block_tail = Some(info);
873 /// Creates a new `LocalDecl` for a internal temporary.
875 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
876 Self::new_local(ty, Mutability::Mut, true, span)
880 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
884 user_ty: UserTypeProjections::none(),
885 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
887 local_info: LocalInfo::Other,
892 /// Builds a `LocalDecl` for the return place.
894 /// This must be inserted into the `local_decls` list as the first local.
896 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
898 mutability: Mutability::Mut,
900 user_ty: UserTypeProjections::none(),
901 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
904 local_info: LocalInfo::Other,
909 /// Debug information pertaining to a user variable.
910 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
911 pub struct VarDebugInfo<'tcx> {
914 /// Source info of the user variable, including the scope
915 /// within which the variable is visible (to debuginfo)
916 /// (see `LocalDecl`'s `source_info` field for more details).
917 pub source_info: SourceInfo,
919 /// Where the data for this user variable is to be found.
920 /// NOTE(eddyb) There's an unenforced invariant that this `Place` is
921 /// based on a `Local`, not a `Static`, and contains no indexing.
922 pub place: Place<'tcx>,
925 ///////////////////////////////////////////////////////////////////////////
928 rustc_index::newtype_index! {
929 pub struct BasicBlock {
931 DEBUG_FORMAT = "bb{}",
932 const START_BLOCK = 0,
937 pub fn start_location(self) -> Location {
938 Location { block: self, statement_index: 0 }
942 ///////////////////////////////////////////////////////////////////////////
943 // BasicBlockData and Terminator
945 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
946 pub struct BasicBlockData<'tcx> {
947 /// List of statements in this block.
948 pub statements: Vec<Statement<'tcx>>,
950 /// Terminator for this block.
952 /// N.B., this should generally ONLY be `None` during construction.
953 /// Therefore, you should generally access it via the
954 /// `terminator()` or `terminator_mut()` methods. The only
955 /// exception is that certain passes, such as `simplify_cfg`, swap
956 /// out the terminator temporarily with `None` while they continue
957 /// to recurse over the set of basic blocks.
958 pub terminator: Option<Terminator<'tcx>>,
960 /// If true, this block lies on an unwind path. This is used
961 /// during codegen where distinct kinds of basic blocks may be
962 /// generated (particularly for MSVC cleanup). Unwind blocks must
963 /// only branch to other unwind blocks.
964 pub is_cleanup: bool,
967 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
968 pub struct Terminator<'tcx> {
969 pub source_info: SourceInfo,
970 pub kind: TerminatorKind<'tcx>,
973 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
974 pub enum TerminatorKind<'tcx> {
975 /// Block should have one successor in the graph; we jump there.
976 Goto { target: BasicBlock },
978 /// Operand evaluates to an integer; jump depending on its value
979 /// to one of the targets, and otherwise fallback to `otherwise`.
981 /// The discriminant value being tested.
982 discr: Operand<'tcx>,
984 /// The type of value being tested.
987 /// Possible values. The locations to branch to in each case
988 /// are found in the corresponding indices from the `targets` vector.
989 values: Cow<'tcx, [u128]>,
991 /// Possible branch sites. The last element of this vector is used
992 /// for the otherwise branch, so targets.len() == values.len() + 1
995 // This invariant is quite non-obvious and also could be improved.
996 // One way to make this invariant is to have something like this instead:
998 // branches: Vec<(ConstInt, BasicBlock)>,
999 // otherwise: Option<BasicBlock> // exhaustive if None
1001 // However we’ve decided to keep this as-is until we figure a case
1002 // where some other approach seems to be strictly better than other.
1003 targets: Vec<BasicBlock>,
1006 /// Indicates that the landing pad is finished and unwinding should
1007 /// continue. Emitted by `build::scope::diverge_cleanup`.
1010 /// Indicates that the landing pad is finished and that the process
1011 /// should abort. Used to prevent unwinding for foreign items.
1014 /// Indicates a normal return. The return place should have
1015 /// been filled in by now. This should occur at most once.
1018 /// Indicates a terminator that can never be reached.
1021 /// Drop the `Place`.
1022 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1024 /// Drop the `Place` and assign the new value over it. This ensures
1025 /// that the assignment to `P` occurs *even if* the destructor for
1026 /// place unwinds. Its semantics are best explained by the
1031 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1039 /// Drop(P, goto BB1, unwind BB2)
1042 /// // P is now uninitialized
1046 /// // P is now uninitialized -- its dtor panicked
1051 location: Place<'tcx>,
1052 value: Operand<'tcx>,
1054 unwind: Option<BasicBlock>,
1057 /// Block ends with a call of a converging function.
1059 /// The function that’s being called.
1060 func: Operand<'tcx>,
1061 /// Arguments the function is called with.
1062 /// These are owned by the callee, which is free to modify them.
1063 /// This allows the memory occupied by "by-value" arguments to be
1064 /// reused across function calls without duplicating the contents.
1065 args: Vec<Operand<'tcx>>,
1066 /// Destination for the return value. If some, the call is converging.
1067 destination: Option<(Place<'tcx>, BasicBlock)>,
1068 /// Cleanups to be done if the call unwinds.
1069 cleanup: Option<BasicBlock>,
1070 /// `true` if this is from a call in HIR rather than from an overloaded
1071 /// operator. True for overloaded function call.
1072 from_hir_call: bool,
1075 /// Jump to the target if the condition has the expected value,
1076 /// otherwise panic with a message and a cleanup target.
1078 cond: Operand<'tcx>,
1080 msg: AssertMessage<'tcx>,
1082 cleanup: Option<BasicBlock>,
1085 /// A suspend point.
1087 /// The value to return.
1088 value: Operand<'tcx>,
1089 /// Where to resume to.
1091 /// Cleanup to be done if the generator is dropped at this suspend point.
1092 drop: Option<BasicBlock>,
1095 /// Indicates the end of the dropping of a generator.
1098 /// A block where control flow only ever takes one real path, but borrowck
1099 /// needs to be more conservative.
1101 /// The target normal control flow will take.
1102 real_target: BasicBlock,
1103 /// A block control flow could conceptually jump to, but won't in
1105 imaginary_target: BasicBlock,
1107 /// A terminator for blocks that only take one path in reality, but where we
1108 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1109 /// This can arise in infinite loops with no function calls for example.
1111 /// The target normal control flow will take.
1112 real_target: BasicBlock,
1113 /// The imaginary cleanup block link. This particular path will never be taken
1114 /// in practice, but in order to avoid fragility we want to always
1115 /// consider it in borrowck. We don't want to accept programs which
1116 /// pass borrowck only when `panic=abort` or some assertions are disabled
1117 /// due to release vs. debug mode builds. This needs to be an `Option` because
1118 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1119 unwind: Option<BasicBlock>,
1123 pub type Successors<'a> =
1124 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1125 pub type SuccessorsMut<'a> =
1126 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1128 impl<'tcx> Terminator<'tcx> {
1129 pub fn successors(&self) -> Successors<'_> {
1130 self.kind.successors()
1133 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1134 self.kind.successors_mut()
1137 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1141 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1142 self.kind.unwind_mut()
1146 impl<'tcx> TerminatorKind<'tcx> {
1149 cond: Operand<'tcx>,
1152 ) -> TerminatorKind<'tcx> {
1153 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1154 TerminatorKind::SwitchInt {
1156 switch_ty: tcx.types.bool,
1157 values: From::from(BOOL_SWITCH_FALSE),
1158 targets: vec![f, t],
1162 pub fn successors(&self) -> Successors<'_> {
1163 use self::TerminatorKind::*;
1170 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1171 Goto { target: ref t }
1172 | Call { destination: None, cleanup: Some(ref t), .. }
1173 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1174 | Yield { resume: ref t, drop: None, .. }
1175 | DropAndReplace { target: ref t, unwind: None, .. }
1176 | Drop { target: ref t, unwind: None, .. }
1177 | Assert { target: ref t, cleanup: None, .. }
1178 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1179 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1180 | Yield { resume: ref t, drop: Some(ref u), .. }
1181 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1182 | Drop { target: ref t, unwind: Some(ref u), .. }
1183 | Assert { target: ref t, cleanup: Some(ref u), .. }
1184 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1185 Some(t).into_iter().chain(slice::from_ref(u))
1187 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1188 FalseEdges { ref real_target, ref imaginary_target } => {
1189 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1194 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1195 use self::TerminatorKind::*;
1202 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1203 Goto { target: ref mut t }
1204 | Call { destination: None, cleanup: Some(ref mut t), .. }
1205 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1206 | Yield { resume: ref mut t, drop: None, .. }
1207 | DropAndReplace { target: ref mut t, unwind: None, .. }
1208 | Drop { target: ref mut t, unwind: None, .. }
1209 | Assert { target: ref mut t, cleanup: None, .. }
1210 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1211 Some(t).into_iter().chain(&mut [])
1213 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1214 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1215 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1216 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1217 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1218 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1219 Some(t).into_iter().chain(slice::from_mut(u))
1221 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1222 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1223 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1228 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1230 TerminatorKind::Goto { .. }
1231 | TerminatorKind::Resume
1232 | TerminatorKind::Abort
1233 | TerminatorKind::Return
1234 | TerminatorKind::Unreachable
1235 | TerminatorKind::GeneratorDrop
1236 | TerminatorKind::Yield { .. }
1237 | TerminatorKind::SwitchInt { .. }
1238 | TerminatorKind::FalseEdges { .. } => None,
1239 TerminatorKind::Call { cleanup: ref unwind, .. }
1240 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1241 | TerminatorKind::DropAndReplace { ref unwind, .. }
1242 | TerminatorKind::Drop { ref unwind, .. }
1243 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1247 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1249 TerminatorKind::Goto { .. }
1250 | TerminatorKind::Resume
1251 | TerminatorKind::Abort
1252 | TerminatorKind::Return
1253 | TerminatorKind::Unreachable
1254 | TerminatorKind::GeneratorDrop
1255 | TerminatorKind::Yield { .. }
1256 | TerminatorKind::SwitchInt { .. }
1257 | TerminatorKind::FalseEdges { .. } => None,
1258 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1259 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1260 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1261 | TerminatorKind::Drop { ref mut unwind, .. }
1262 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1267 impl<'tcx> BasicBlockData<'tcx> {
1268 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1269 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1272 /// Accessor for terminator.
1274 /// Terminator may not be None after construction of the basic block is complete. This accessor
1275 /// provides a convenience way to reach the terminator.
1276 pub fn terminator(&self) -> &Terminator<'tcx> {
1277 self.terminator.as_ref().expect("invalid terminator state")
1280 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1281 self.terminator.as_mut().expect("invalid terminator state")
1284 pub fn retain_statements<F>(&mut self, mut f: F)
1286 F: FnMut(&mut Statement<'_>) -> bool,
1288 for s in &mut self.statements {
1295 pub fn expand_statements<F, I>(&mut self, mut f: F)
1297 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1298 I: iter::TrustedLen<Item = Statement<'tcx>>,
1300 // Gather all the iterators we'll need to splice in, and their positions.
1301 let mut splices: Vec<(usize, I)> = vec![];
1302 let mut extra_stmts = 0;
1303 for (i, s) in self.statements.iter_mut().enumerate() {
1304 if let Some(mut new_stmts) = f(s) {
1305 if let Some(first) = new_stmts.next() {
1306 // We can already store the first new statement.
1309 // Save the other statements for optimized splicing.
1310 let remaining = new_stmts.size_hint().0;
1312 splices.push((i + 1 + extra_stmts, new_stmts));
1313 extra_stmts += remaining;
1321 // Splice in the new statements, from the end of the block.
1322 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1323 // where a range of elements ("gap") is left uninitialized, with
1324 // splicing adding new elements to the end of that gap and moving
1325 // existing elements from before the gap to the end of the gap.
1326 // For now, this is safe code, emulating a gap but initializing it.
1327 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1328 self.statements.resize(
1331 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1332 kind: StatementKind::Nop,
1335 for (splice_start, new_stmts) in splices.into_iter().rev() {
1336 let splice_end = splice_start + new_stmts.size_hint().0;
1337 while gap.end > splice_end {
1340 self.statements.swap(gap.start, gap.end);
1342 self.statements.splice(splice_start..splice_end, new_stmts);
1343 gap.end = splice_start;
1347 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1348 if index < self.statements.len() {
1349 &self.statements[index]
1356 impl<'tcx> Debug for TerminatorKind<'tcx> {
1357 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1358 self.fmt_head(fmt)?;
1359 let successor_count = self.successors().count();
1360 let labels = self.fmt_successor_labels();
1361 assert_eq!(successor_count, labels.len());
1363 match successor_count {
1366 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1369 write!(fmt, " -> [")?;
1370 for (i, target) in self.successors().enumerate() {
1374 write!(fmt, "{}: {:?}", labels[i], target)?;
1382 impl<'tcx> TerminatorKind<'tcx> {
1383 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1384 /// successor basic block, if any. The only information not included is the list of possible
1385 /// successors, which may be rendered differently between the text and the graphviz format.
1386 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1387 use self::TerminatorKind::*;
1389 Goto { .. } => write!(fmt, "goto"),
1390 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1391 Return => write!(fmt, "return"),
1392 GeneratorDrop => write!(fmt, "generator_drop"),
1393 Resume => write!(fmt, "resume"),
1394 Abort => write!(fmt, "abort"),
1395 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1396 Unreachable => write!(fmt, "unreachable"),
1397 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1398 DropAndReplace { ref location, ref value, .. } => {
1399 write!(fmt, "replace({:?} <- {:?})", location, value)
1401 Call { ref func, ref args, ref destination, .. } => {
1402 if let Some((ref destination, _)) = *destination {
1403 write!(fmt, "{:?} = ", destination)?;
1405 write!(fmt, "{:?}(", func)?;
1406 for (index, arg) in args.iter().enumerate() {
1410 write!(fmt, "{:?}", arg)?;
1414 Assert { ref cond, expected, ref msg, .. } => {
1415 write!(fmt, "assert(")?;
1419 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1421 FalseEdges { .. } => write!(fmt, "falseEdges"),
1422 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1426 /// Returns the list of labels for the edges to the successor basic blocks.
1427 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1428 use self::TerminatorKind::*;
1430 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1431 Goto { .. } => vec!["".into()],
1432 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1433 let param_env = ty::ParamEnv::empty();
1434 let switch_ty = tcx.lift(&switch_ty).unwrap();
1435 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1439 ty::Const::from_scalar(
1441 Scalar::from_uint(u, size).into(),
1447 .chain(iter::once("otherwise".into()))
1450 Call { destination: Some(_), cleanup: Some(_), .. } => {
1451 vec!["return".into(), "unwind".into()]
1453 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1454 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1455 Call { destination: None, cleanup: None, .. } => vec![],
1456 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1457 Yield { drop: None, .. } => vec!["resume".into()],
1458 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1459 vec!["return".into()]
1461 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1462 vec!["return".into(), "unwind".into()]
1464 Assert { cleanup: None, .. } => vec!["".into()],
1465 Assert { .. } => vec!["success".into(), "unwind".into()],
1466 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1467 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1468 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1473 ///////////////////////////////////////////////////////////////////////////
1476 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1477 pub struct Statement<'tcx> {
1478 pub source_info: SourceInfo,
1479 pub kind: StatementKind<'tcx>,
1482 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1483 #[cfg(target_arch = "x86_64")]
1484 static_assert_size!(Statement<'_>, 32);
1486 impl Statement<'_> {
1487 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1488 /// invalidating statement indices in `Location`s.
1489 pub fn make_nop(&mut self) {
1490 self.kind = StatementKind::Nop
1493 /// Changes a statement to a nop and returns the original statement.
1494 pub fn replace_nop(&mut self) -> Self {
1496 source_info: self.source_info,
1497 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1502 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1503 pub enum StatementKind<'tcx> {
1504 /// Write the RHS Rvalue to the LHS Place.
1505 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1507 /// This represents all the reading that a pattern match may do
1508 /// (e.g., inspecting constants and discriminant values), and the
1509 /// kind of pattern it comes from. This is in order to adapt potential
1510 /// error messages to these specific patterns.
1512 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1513 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1514 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1516 /// Write the discriminant for a variant to the enum Place.
1517 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1519 /// Start a live range for the storage of the local.
1522 /// End the current live range for the storage of the local.
1525 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1526 /// of `StatementKind` low.
1527 InlineAsm(Box<InlineAsm<'tcx>>),
1529 /// Retag references in the given place, ensuring they got fresh tags. This is
1530 /// part of the Stacked Borrows model. These statements are currently only interpreted
1531 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1532 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1533 /// for more details.
1534 Retag(RetagKind, Box<Place<'tcx>>),
1536 /// Encodes a user's type ascription. These need to be preserved
1537 /// intact so that NLL can respect them. For example:
1541 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1542 /// to the user-given type `T`. The effect depends on the specified variance:
1544 /// - `Covariant` -- requires that `T_y <: T`
1545 /// - `Contravariant` -- requires that `T_y :> T`
1546 /// - `Invariant` -- requires that `T_y == T`
1547 /// - `Bivariant` -- no effect
1548 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1550 /// No-op. Useful for deleting instructions without affecting statement indices.
1554 /// Describes what kind of retag is to be performed.
1555 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1556 pub enum RetagKind {
1557 /// The initial retag when entering a function.
1559 /// Retag preparing for a two-phase borrow.
1561 /// Retagging raw pointers.
1563 /// A "normal" retag.
1567 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1568 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable, PartialEq)]
1569 pub enum FakeReadCause {
1570 /// Inject a fake read of the borrowed input at the end of each guards
1573 /// This should ensure that you cannot change the variant for an enum while
1574 /// you are in the midst of matching on it.
1577 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1578 /// generate a read of x to check that it is initialized and safe.
1581 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1582 /// in a match guard to ensure that it's value hasn't change by the time
1583 /// we create the OutsideGuard version.
1586 /// Officially, the semantics of
1588 /// `let pattern = <expr>;`
1590 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1591 /// into the pattern.
1593 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1594 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1595 /// but in some cases it can affect the borrow checker, as in #53695.
1596 /// Therefore, we insert a "fake read" here to ensure that we get
1597 /// appropriate errors.
1600 /// If we have an index expression like
1602 /// (*x)[1][{ x = y; 4}]
1604 /// then the first bounds check is invalidated when we evaluate the second
1605 /// index expression. Thus we create a fake borrow of `x` across the second
1606 /// indexer, which will cause a borrow check error.
1610 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1611 pub struct InlineAsm<'tcx> {
1612 pub asm: hir::InlineAsmInner,
1613 pub outputs: Box<[Place<'tcx>]>,
1614 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1617 impl Debug for Statement<'_> {
1618 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1619 use self::StatementKind::*;
1621 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1622 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1623 Retag(ref kind, ref place) => write!(
1627 RetagKind::FnEntry => "[fn entry] ",
1628 RetagKind::TwoPhase => "[2phase] ",
1629 RetagKind::Raw => "[raw] ",
1630 RetagKind::Default => "",
1634 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1635 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1636 SetDiscriminant { ref place, variant_index } => {
1637 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1639 InlineAsm(ref asm) => {
1640 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1642 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1643 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1645 Nop => write!(fmt, "nop"),
1650 ///////////////////////////////////////////////////////////////////////////
1653 /// A path to a value; something that can be evaluated without
1654 /// changing or disturbing program state.
1656 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1658 pub struct Place<'tcx> {
1659 pub base: PlaceBase<'tcx>,
1661 /// projection out of a place (access a field, deref a pointer, etc)
1662 pub projection: &'tcx List<PlaceElem<'tcx>>,
1665 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1668 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1670 pub enum PlaceBase<'tcx> {
1674 /// static or static mut variable
1675 Static(Box<Static<'tcx>>),
1678 /// We store the normalized type to avoid requiring normalization when reading MIR
1679 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
1680 RustcEncodable, RustcDecodable, HashStable)]
1681 pub struct Static<'tcx> {
1683 pub kind: StaticKind<'tcx>,
1684 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1685 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1686 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1687 /// into the calling frame.
1692 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1694 pub enum StaticKind<'tcx> {
1695 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1696 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1697 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1698 Promoted(Promoted, SubstsRef<'tcx>),
1702 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1703 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1704 pub enum ProjectionElem<V, T> {
1709 /// These indices are generated by slice patterns. Easiest to explain
1713 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1714 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1715 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1716 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1719 /// index or -index (in Python terms), depending on from_end
1721 /// thing being indexed must be at least this long
1723 /// counting backwards from end?
1727 /// These indices are generated by slice patterns.
1729 /// slice[from:-to] in Python terms.
1735 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1736 /// this for ADTs with more than one variant. It may be better to
1737 /// just introduce it always, or always for enums.
1739 /// The included Symbol is the name of the variant, used for printing MIR.
1740 Downcast(Option<Symbol>, VariantIdx),
1743 impl<V, T> ProjectionElem<V, T> {
1744 /// Returns `true` if the target of this projection may refer to a different region of memory
1746 fn is_indirect(&self) -> bool {
1748 Self::Deref => true,
1752 | Self::ConstantIndex { .. }
1753 | Self::Subslice { .. }
1754 | Self::Downcast(_, _)
1760 /// Alias for projections as they appear in places, where the base is a place
1761 /// and the index is a local.
1762 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1764 impl<'tcx> Copy for PlaceElem<'tcx> { }
1766 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1767 #[cfg(target_arch = "x86_64")]
1768 static_assert_size!(PlaceElem<'_>, 16);
1770 /// Alias for projections as they appear in `UserTypeProjection`, where we
1771 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1772 pub type ProjectionKind = ProjectionElem<(), ()>;
1774 rustc_index::newtype_index! {
1777 DEBUG_FORMAT = "field[{}]"
1781 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1782 pub struct PlaceRef<'a, 'tcx> {
1783 pub base: &'a PlaceBase<'tcx>,
1784 pub projection: &'a [PlaceElem<'tcx>],
1787 impl<'tcx> Place<'tcx> {
1788 // FIXME change this to a const fn by also making List::empty a const fn.
1789 pub fn return_place() -> Place<'tcx> {
1791 base: PlaceBase::Local(RETURN_PLACE),
1792 projection: List::empty(),
1796 /// Returns `true` if this `Place` contains a `Deref` projection.
1798 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1799 /// same region of memory as its base.
1800 pub fn is_indirect(&self) -> bool {
1801 self.projection.iter().any(|elem| elem.is_indirect())
1804 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1805 /// a single deref of a local.
1807 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1808 pub fn local_or_deref_local(&self) -> Option<Local> {
1809 match self.as_ref() {
1811 base: &PlaceBase::Local(local),
1815 base: &PlaceBase::Local(local),
1816 projection: &[ProjectionElem::Deref],
1822 /// If this place represents a local variable like `_X` with no
1823 /// projections, return `Some(_X)`.
1824 pub fn as_local(&self) -> Option<Local> {
1825 self.as_ref().as_local()
1828 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1831 projection: &self.projection,
1836 impl From<Local> for Place<'_> {
1837 fn from(local: Local) -> Self {
1840 projection: List::empty(),
1845 impl From<Local> for PlaceBase<'_> {
1846 fn from(local: Local) -> Self {
1847 PlaceBase::Local(local)
1851 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1852 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1853 /// a single deref of a local.
1855 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1856 pub fn local_or_deref_local(&self) -> Option<Local> {
1859 base: PlaceBase::Local(local),
1863 base: PlaceBase::Local(local),
1864 projection: [ProjectionElem::Deref],
1870 /// If this place represents a local variable like `_X` with no
1871 /// projections, return `Some(_X)`.
1872 pub fn as_local(&self) -> Option<Local> {
1874 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1880 impl Debug for Place<'_> {
1881 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1882 for elem in self.projection.iter().rev() {
1884 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1885 write!(fmt, "(").unwrap();
1887 ProjectionElem::Deref => {
1888 write!(fmt, "(*").unwrap();
1890 ProjectionElem::Index(_)
1891 | ProjectionElem::ConstantIndex { .. }
1892 | ProjectionElem::Subslice { .. } => {}
1896 write!(fmt, "{:?}", self.base)?;
1898 for elem in self.projection.iter() {
1900 ProjectionElem::Downcast(Some(name), _index) => {
1901 write!(fmt, " as {})", name)?;
1903 ProjectionElem::Downcast(None, index) => {
1904 write!(fmt, " as variant#{:?})", index)?;
1906 ProjectionElem::Deref => {
1909 ProjectionElem::Field(field, ty) => {
1910 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1912 ProjectionElem::Index(ref index) => {
1913 write!(fmt, "[{:?}]", index)?;
1915 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1916 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1918 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1919 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1921 ProjectionElem::Subslice { from, to } if *to == 0 => {
1922 write!(fmt, "[{:?}:]", from)?;
1924 ProjectionElem::Subslice { from, to } if *from == 0 => {
1925 write!(fmt, "[:-{:?}]", to)?;
1927 ProjectionElem::Subslice { from, to } => {
1928 write!(fmt, "[{:?}:-{:?}]", from, to)?;
1937 impl Debug for PlaceBase<'_> {
1938 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1940 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
1941 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
1942 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
1944 PlaceBase::Static(box self::Static {
1945 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
1947 write!(fmt, "({:?}: {:?})", promoted, ty)
1953 ///////////////////////////////////////////////////////////////////////////
1956 rustc_index::newtype_index! {
1957 pub struct SourceScope {
1959 DEBUG_FORMAT = "scope[{}]",
1960 const OUTERMOST_SOURCE_SCOPE = 0,
1964 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1965 pub struct SourceScopeData {
1967 pub parent_scope: Option<SourceScope>,
1969 /// Crate-local information for this source scope, that can't (and
1970 /// needn't) be tracked across crates.
1971 pub local_data: ClearCrossCrate<SourceScopeLocalData>,
1974 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1975 pub struct SourceScopeLocalData {
1976 /// An `HirId` with lint levels equivalent to this scope's lint levels.
1977 pub lint_root: hir::HirId,
1978 /// The unsafe block that contains this node.
1982 ///////////////////////////////////////////////////////////////////////////
1985 /// These are values that can appear inside an rvalue. They are intentionally
1986 /// limited to prevent rvalues from being nested in one another.
1987 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
1988 pub enum Operand<'tcx> {
1989 /// Copy: The value must be available for use afterwards.
1991 /// This implies that the type of the place must be `Copy`; this is true
1992 /// by construction during build, but also checked by the MIR type checker.
1995 /// Move: The value (including old borrows of it) will not be used again.
1997 /// Safe for values of all types (modulo future developments towards `?Move`).
1998 /// Correct usage patterns are enforced by the borrow checker for safe code.
1999 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2002 /// Synthesizes a constant value.
2003 Constant(Box<Constant<'tcx>>),
2006 impl<'tcx> Debug for Operand<'tcx> {
2007 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2008 use self::Operand::*;
2010 Constant(ref a) => write!(fmt, "{:?}", a),
2011 Copy(ref place) => write!(fmt, "{:?}", place),
2012 Move(ref place) => write!(fmt, "move {:?}", place),
2017 impl<'tcx> Operand<'tcx> {
2018 /// Convenience helper to make a constant that refers to the fn
2019 /// with given `DefId` and substs. Since this is used to synthesize
2020 /// MIR, assumes `user_ty` is None.
2021 pub fn function_handle(
2024 substs: SubstsRef<'tcx>,
2027 let ty = tcx.type_of(def_id).subst(tcx, substs);
2028 Operand::Constant(box Constant {
2031 literal: ty::Const::zero_sized(tcx, ty),
2035 pub fn to_copy(&self) -> Self {
2037 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2038 Operand::Move(ref place) => Operand::Copy(place.clone()),
2043 ///////////////////////////////////////////////////////////////////////////
2046 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2047 pub enum Rvalue<'tcx> {
2048 /// x (either a move or copy, depending on type of x)
2052 Repeat(Operand<'tcx>, u64),
2055 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2057 /// length of a [X] or [X;n] value
2060 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2062 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2063 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2065 NullaryOp(NullOp, Ty<'tcx>),
2066 UnaryOp(UnOp, Operand<'tcx>),
2068 /// Read the discriminant of an ADT.
2070 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2071 /// be defined to return, say, a 0) if ADT is not an enum.
2072 Discriminant(Place<'tcx>),
2074 /// Creates an aggregate value, like a tuple or struct. This is
2075 /// only needed because we want to distinguish `dest = Foo { x:
2076 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2077 /// that `Foo` has a destructor. These rvalues can be optimized
2078 /// away after type-checking and before lowering.
2079 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2082 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2085 Pointer(PointerCast),
2088 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2089 pub enum AggregateKind<'tcx> {
2090 /// The type is of the element
2094 /// The second field is the variant index. It's equal to 0 for struct
2095 /// and union expressions. The fourth field is
2096 /// active field number and is present only for union expressions
2097 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2098 /// active field index would identity the field `c`
2099 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2101 Closure(DefId, SubstsRef<'tcx>),
2102 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2105 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2107 /// The `+` operator (addition)
2109 /// The `-` operator (subtraction)
2111 /// The `*` operator (multiplication)
2113 /// The `/` operator (division)
2115 /// The `%` operator (modulus)
2117 /// The `^` operator (bitwise xor)
2119 /// The `&` operator (bitwise and)
2121 /// The `|` operator (bitwise or)
2123 /// The `<<` operator (shift left)
2125 /// The `>>` operator (shift right)
2127 /// The `==` operator (equality)
2129 /// The `<` operator (less than)
2131 /// The `<=` operator (less than or equal to)
2133 /// The `!=` operator (not equal to)
2135 /// The `>=` operator (greater than or equal to)
2137 /// The `>` operator (greater than)
2139 /// The `ptr.offset` operator
2144 pub fn is_checkable(self) -> bool {
2147 Add | Sub | Mul | Shl | Shr => true,
2153 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2155 /// Returns the size of a value of that type
2157 /// Creates a new uninitialized box for a value of that type
2161 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2163 /// The `!` operator for logical inversion
2165 /// The `-` operator for negation
2169 impl<'tcx> Debug for Rvalue<'tcx> {
2170 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2171 use self::Rvalue::*;
2174 Use(ref place) => write!(fmt, "{:?}", place),
2175 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2176 Len(ref a) => write!(fmt, "Len({:?})", a),
2177 Cast(ref kind, ref place, ref ty) => {
2178 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2180 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2181 CheckedBinaryOp(ref op, ref a, ref b) => {
2182 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2184 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2185 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2186 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2187 Ref(region, borrow_kind, ref place) => {
2188 let kind_str = match borrow_kind {
2189 BorrowKind::Shared => "",
2190 BorrowKind::Shallow => "shallow ",
2191 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2194 // When printing regions, add trailing space if necessary.
2195 let print_region = ty::tls::with(|tcx| {
2196 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2198 let region = if print_region {
2199 let mut region = region.to_string();
2200 if region.len() > 0 {
2205 // Do not even print 'static
2208 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2211 Aggregate(ref kind, ref places) => {
2212 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2213 let mut tuple_fmt = fmt.debug_tuple("");
2214 for place in places {
2215 tuple_fmt.field(place);
2221 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2223 AggregateKind::Tuple => match places.len() {
2224 0 => write!(fmt, "()"),
2225 1 => write!(fmt, "({:?},)", places[0]),
2226 _ => fmt_tuple(fmt, places),
2229 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2230 let variant_def = &adt_def.variants[variant];
2233 ty::tls::with(|tcx| {
2234 let substs = tcx.lift(&substs).expect("could not lift for printing");
2235 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2236 .print_def_path(variant_def.def_id, substs)?;
2240 match variant_def.ctor_kind {
2241 CtorKind::Const => Ok(()),
2242 CtorKind::Fn => fmt_tuple(fmt, places),
2243 CtorKind::Fictive => {
2244 let mut struct_fmt = fmt.debug_struct("");
2245 for (field, place) in variant_def.fields.iter().zip(places) {
2246 struct_fmt.field(&field.ident.as_str(), place);
2253 AggregateKind::Closure(def_id, substs) => ty::tls::with(|tcx| {
2254 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2255 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2256 let substs = tcx.lift(&substs).unwrap();
2259 tcx.def_path_str_with_substs(def_id, substs),
2262 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2264 let mut struct_fmt = fmt.debug_struct(&name);
2266 if let Some(upvars) = tcx.upvars(def_id) {
2267 for (&var_id, place) in upvars.keys().zip(places) {
2268 let var_name = tcx.hir().name(var_id);
2269 struct_fmt.field(&var_name.as_str(), place);
2275 write!(fmt, "[closure]")
2279 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2280 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2281 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2282 let mut struct_fmt = fmt.debug_struct(&name);
2284 if let Some(upvars) = tcx.upvars(def_id) {
2285 for (&var_id, place) in upvars.keys().zip(places) {
2286 let var_name = tcx.hir().name(var_id);
2287 struct_fmt.field(&var_name.as_str(), place);
2293 write!(fmt, "[generator]")
2302 ///////////////////////////////////////////////////////////////////////////
2305 /// Two constants are equal if they are the same constant. Note that
2306 /// this does not necessarily mean that they are "==" in Rust -- in
2307 /// particular one must be wary of `NaN`!
2309 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2310 pub struct Constant<'tcx> {
2313 /// Optional user-given type: for something like
2314 /// `collect::<Vec<_>>`, this would be present and would
2315 /// indicate that `Vec<_>` was explicitly specified.
2317 /// Needed for NLL to impose user-given type constraints.
2318 pub user_ty: Option<UserTypeAnnotationIndex>,
2320 pub literal: &'tcx ty::Const<'tcx>,
2323 impl Constant<'tcx> {
2324 pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
2325 match self.literal.val.try_to_scalar() {
2326 Some(Scalar::Ptr(ptr)) => match tcx.alloc_map.lock().get(ptr.alloc_id) {
2327 Some(GlobalAlloc::Static(def_id)) => Some(def_id),
2330 tcx.sess.delay_span_bug(
2331 DUMMY_SP, "MIR cannot contain dangling const pointers",
2341 /// A collection of projections into user types.
2343 /// They are projections because a binding can occur a part of a
2344 /// parent pattern that has been ascribed a type.
2346 /// Its a collection because there can be multiple type ascriptions on
2347 /// the path from the root of the pattern down to the binding itself.
2352 /// struct S<'a>((i32, &'a str), String);
2353 /// let S((_, w): (i32, &'static str), _): S = ...;
2354 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2355 /// // --------------------------------- ^ (2)
2358 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2359 /// ascribed the type `(i32, &'static str)`.
2361 /// The highlights labelled `(2)` show the whole pattern being
2362 /// ascribed the type `S`.
2364 /// In this example, when we descend to `w`, we will have built up the
2365 /// following two projected types:
2367 /// * base: `S`, projection: `(base.0).1`
2368 /// * base: `(i32, &'static str)`, projection: `base.1`
2370 /// The first will lead to the constraint `w: &'1 str` (for some
2371 /// inferred region `'1`). The second will lead to the constraint `w:
2373 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2374 pub struct UserTypeProjections {
2375 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2378 impl<'tcx> UserTypeProjections {
2379 pub fn none() -> Self {
2380 UserTypeProjections { contents: vec![] }
2383 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2384 UserTypeProjections { contents: projs.collect() }
2387 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2388 self.contents.iter()
2391 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2392 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2395 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2396 self.contents.push((user_ty.clone(), span));
2402 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2404 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2408 pub fn index(self) -> Self {
2409 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2412 pub fn subslice(self, from: u32, to: u32) -> Self {
2413 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2416 pub fn deref(self) -> Self {
2417 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2420 pub fn leaf(self, field: Field) -> Self {
2421 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2424 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2425 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2429 /// Encodes the effect of a user-supplied type annotation on the
2430 /// subcomponents of a pattern. The effect is determined by applying the
2431 /// given list of proejctions to some underlying base type. Often,
2432 /// the projection element list `projs` is empty, in which case this
2433 /// directly encodes a type in `base`. But in the case of complex patterns with
2434 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2435 /// in which case the `projs` vector is used.
2439 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2441 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2442 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2443 /// determined by finding the type of the `.0` field from `T`.
2444 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2445 pub struct UserTypeProjection {
2446 pub base: UserTypeAnnotationIndex,
2447 pub projs: Vec<ProjectionKind>,
2450 impl Copy for ProjectionKind {}
2452 impl UserTypeProjection {
2453 pub(crate) fn index(mut self) -> Self {
2454 self.projs.push(ProjectionElem::Index(()));
2458 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2459 self.projs.push(ProjectionElem::Subslice { from, to });
2463 pub(crate) fn deref(mut self) -> Self {
2464 self.projs.push(ProjectionElem::Deref);
2468 pub(crate) fn leaf(mut self, field: Field) -> Self {
2469 self.projs.push(ProjectionElem::Field(field, ()));
2473 pub(crate) fn variant(
2475 adt_def: &'tcx AdtDef,
2476 variant_index: VariantIdx,
2479 self.projs.push(ProjectionElem::Downcast(
2480 Some(adt_def.variants[variant_index].ident.name),
2483 self.projs.push(ProjectionElem::Field(field, ()));
2488 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2490 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2491 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2492 use crate::mir::ProjectionElem::*;
2494 let base = self.base.fold_with(folder);
2495 let projs: Vec<_> = self
2498 .map(|elem| match elem {
2500 Field(f, ()) => Field(f.clone(), ()),
2501 Index(()) => Index(()),
2502 elem => elem.clone(),
2506 UserTypeProjection { base, projs }
2509 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2510 self.base.visit_with(visitor)
2511 // Note: there's nothing in `self.proj` to visit.
2515 rustc_index::newtype_index! {
2516 pub struct Promoted {
2518 DEBUG_FORMAT = "promoted[{}]"
2522 impl<'tcx> Debug for Constant<'tcx> {
2523 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2524 write!(fmt, "{}", self)
2528 impl<'tcx> Display for Constant<'tcx> {
2529 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2530 write!(fmt, "const ")?;
2531 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2532 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2533 // detailed and just not '{pointer}'.
2534 if let ty::RawPtr(_) = self.literal.ty.kind {
2535 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2537 write!(fmt, "{}", self.literal)
2542 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2543 type Node = BasicBlock;
2546 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2547 fn num_nodes(&self) -> usize {
2548 self.basic_blocks.len()
2552 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2553 fn start_node(&self) -> Self::Node {
2558 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2562 ) -> <Self as GraphSuccessors<'_>>::Iter {
2563 self.basic_blocks[node].terminator().successors().cloned()
2567 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2568 type Item = BasicBlock;
2569 type Iter = iter::Cloned<Successors<'b>>;
2572 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2573 pub struct Location {
2574 /// The block that the location is within.
2575 pub block: BasicBlock,
2577 /// The location is the position of the start of the statement; or, if
2578 /// `statement_index` equals the number of statements, then the start of the
2580 pub statement_index: usize,
2583 impl fmt::Debug for Location {
2584 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2585 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2590 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2592 /// Returns the location immediately after this one within the enclosing block.
2594 /// Note that if this location represents a terminator, then the
2595 /// resulting location would be out of bounds and invalid.
2596 pub fn successor_within_block(&self) -> Location {
2597 Location { block: self.block, statement_index: self.statement_index + 1 }
2600 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2601 pub fn is_predecessor_of<'tcx>(
2604 body: ReadOnlyBodyCache<'_, 'tcx>
2606 // If we are in the same block as the other location and are an earlier statement
2607 // then we are a predecessor of `other`.
2608 if self.block == other.block && self.statement_index < other.statement_index {
2612 // If we're in another block, then we want to check that block is a predecessor of `other`.
2613 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).to_vec();
2614 let mut visited = FxHashSet::default();
2616 while let Some(block) = queue.pop() {
2617 // If we haven't visited this block before, then make sure we visit it's predecessors.
2618 if visited.insert(block) {
2619 queue.extend(body.predecessors_for(block).iter().cloned());
2624 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2625 // we found that block by looking at the predecessors of `other`).
2626 if self.block == block {
2634 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2635 if self.block == other.block {
2636 self.statement_index <= other.statement_index
2638 dominators.is_dominated_by(other.block, self.block)
2643 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2644 pub enum UnsafetyViolationKind {
2646 /// Permitted both in `const fn`s and regular `fn`s.
2648 BorrowPacked(hir::HirId),
2651 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2652 pub struct UnsafetyViolation {
2653 pub source_info: SourceInfo,
2654 pub description: Symbol,
2655 pub details: Symbol,
2656 pub kind: UnsafetyViolationKind,
2659 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2660 pub struct UnsafetyCheckResult {
2661 /// Violations that are propagated *upwards* from this function.
2662 pub violations: Lrc<[UnsafetyViolation]>,
2663 /// `unsafe` blocks in this function, along with whether they are used. This is
2664 /// used for the "unused_unsafe" lint.
2665 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2668 rustc_index::newtype_index! {
2669 pub struct GeneratorSavedLocal {
2671 DEBUG_FORMAT = "_{}",
2675 /// The layout of generator state.
2676 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2677 pub struct GeneratorLayout<'tcx> {
2678 /// The type of every local stored inside the generator.
2679 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2681 /// Which of the above fields are in each variant. Note that one field may
2682 /// be stored in multiple variants.
2683 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2685 /// Which saved locals are storage-live at the same time. Locals that do not
2686 /// have conflicts with each other are allowed to overlap in the computed
2688 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2691 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2692 pub struct BorrowCheckResult<'tcx> {
2693 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2694 pub used_mut_upvars: SmallVec<[Field; 8]>,
2697 /// The result of the `mir_const_qualif` query.
2699 /// Each field corresponds to an implementer of the `Qualif` trait in
2700 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2702 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2703 pub struct ConstQualifs {
2704 pub has_mut_interior: bool,
2705 pub needs_drop: bool,
2708 /// After we borrow check a closure, we are left with various
2709 /// requirements that we have inferred between the free regions that
2710 /// appear in the closure's signature or on its field types. These
2711 /// requirements are then verified and proved by the closure's
2712 /// creating function. This struct encodes those requirements.
2714 /// The requirements are listed as being between various
2715 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2716 /// vids refer to the free regions that appear in the closure (or
2717 /// generator's) type, in order of appearance. (This numbering is
2718 /// actually defined by the `UniversalRegions` struct in the NLL
2719 /// region checker. See for example
2720 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2721 /// regions in the closure's type "as if" they were erased, so their
2722 /// precise identity is not important, only their position.
2724 /// Example: If type check produces a closure with the closure substs:
2727 /// ClosureSubsts = [
2728 /// i8, // the "closure kind"
2729 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2730 /// &'a String, // some upvar
2734 /// here, there is one unique free region (`'a`) but it appears
2735 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2738 /// ClosureSubsts = [
2739 /// i8, // the "closure kind"
2740 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2741 /// &'2 String, // some upvar
2745 /// Now the code might impose a requirement like `'1: '2`. When an
2746 /// instance of the closure is created, the corresponding free regions
2747 /// can be extracted from its type and constrained to have the given
2748 /// outlives relationship.
2750 /// In some cases, we have to record outlives requirements between
2751 /// types and regions as well. In that case, if those types include
2752 /// any regions, those regions are recorded as `ReClosureBound`
2753 /// instances assigned one of these same indices. Those regions will
2754 /// be substituted away by the creator. We use `ReClosureBound` in
2755 /// that case because the regions must be allocated in the global
2756 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2757 /// internally within the rest of the NLL code).
2758 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2759 pub struct ClosureRegionRequirements<'tcx> {
2760 /// The number of external regions defined on the closure. In our
2761 /// example above, it would be 3 -- one for `'static`, then `'1`
2762 /// and `'2`. This is just used for a sanity check later on, to
2763 /// make sure that the number of regions we see at the callsite
2765 pub num_external_vids: usize,
2767 /// Requirements between the various free regions defined in
2769 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2772 /// Indicates an outlives-constraint between a type or between two
2773 /// free regions declared on the closure.
2774 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2775 pub struct ClosureOutlivesRequirement<'tcx> {
2776 // This region or type ...
2777 pub subject: ClosureOutlivesSubject<'tcx>,
2779 // ... must outlive this one.
2780 pub outlived_free_region: ty::RegionVid,
2782 // If not, report an error here ...
2783 pub blame_span: Span,
2785 // ... due to this reason.
2786 pub category: ConstraintCategory,
2789 /// Outlives-constraints can be categorized to determine whether and why they
2790 /// are interesting (for error reporting). Order of variants indicates sort
2791 /// order of the category, thereby influencing diagnostic output.
2793 /// See also [rustc_mir::borrow_check::nll::constraints].
2807 pub enum ConstraintCategory {
2815 /// A constraint that came from checking the body of a closure.
2817 /// We try to get the category that the closure used when reporting this.
2825 /// A "boring" constraint (caused by the given location) is one that
2826 /// the user probably doesn't want to see described in diagnostics,
2827 /// because it is kind of an artifact of the type system setup.
2828 /// Example: `x = Foo { field: y }` technically creates
2829 /// intermediate regions representing the "type of `Foo { field: y
2830 /// }`", and data flows from `y` into those variables, but they
2831 /// are not very interesting. The assignment into `x` on the other
2834 // Boring and applicable everywhere.
2837 /// A constraint that doesn't correspond to anything the user sees.
2841 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2842 /// that must outlive some region.
2843 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2844 pub enum ClosureOutlivesSubject<'tcx> {
2845 /// Subject is a type, typically a type parameter, but could also
2846 /// be a projection. Indicates a requirement like `T: 'a` being
2847 /// passed to the caller, where the type here is `T`.
2849 /// The type here is guaranteed not to contain any free regions at
2853 /// Subject is a free region from the closure. Indicates a requirement
2854 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2855 Region(ty::RegionVid),
2859 * `TypeFoldable` implementations for MIR types
2862 CloneTypeFoldableAndLiftImpls! {
2871 SourceScopeLocalData,
2872 UserTypeAnnotationIndex,
2875 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2876 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2877 use crate::mir::TerminatorKind::*;
2879 let kind = match self.kind {
2880 Goto { target } => Goto { target },
2881 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2882 discr: discr.fold_with(folder),
2883 switch_ty: switch_ty.fold_with(folder),
2884 values: values.clone(),
2885 targets: targets.clone(),
2887 Drop { ref location, target, unwind } => {
2888 Drop { location: location.fold_with(folder), target, unwind }
2890 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2891 location: location.fold_with(folder),
2892 value: value.fold_with(folder),
2896 Yield { ref value, resume, drop } => {
2897 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2899 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2901 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2904 func: func.fold_with(folder),
2905 args: args.fold_with(folder),
2911 Assert { ref cond, expected, ref msg, target, cleanup } => {
2913 let msg = match msg {
2914 BoundsCheck { ref len, ref index } =>
2916 len: len.fold_with(folder),
2917 index: index.fold_with(folder),
2919 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2920 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2923 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2925 GeneratorDrop => GeneratorDrop,
2929 Unreachable => Unreachable,
2930 FalseEdges { real_target, imaginary_target } => {
2931 FalseEdges { real_target, imaginary_target }
2933 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
2935 Terminator { source_info: self.source_info, kind }
2938 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2939 use crate::mir::TerminatorKind::*;
2942 SwitchInt { ref discr, switch_ty, .. } => {
2943 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
2945 Drop { ref location, .. } => location.visit_with(visitor),
2946 DropAndReplace { ref location, ref value, .. } => {
2947 location.visit_with(visitor) || value.visit_with(visitor)
2949 Yield { ref value, .. } => value.visit_with(visitor),
2950 Call { ref func, ref args, ref destination, .. } => {
2951 let dest = if let Some((ref loc, _)) = *destination {
2952 loc.visit_with(visitor)
2956 dest || func.visit_with(visitor) || args.visit_with(visitor)
2958 Assert { ref cond, ref msg, .. } => {
2959 if cond.visit_with(visitor) {
2962 BoundsCheck { ref len, ref index } =>
2963 len.visit_with(visitor) || index.visit_with(visitor),
2964 Panic { .. } | Overflow(_) | OverflowNeg |
2965 DivisionByZero | RemainderByZero |
2966 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2980 | FalseUnwind { .. } => false,
2985 impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
2986 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
2990 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
2995 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2996 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2998 base: self.base.fold_with(folder),
2999 projection: self.projection.fold_with(folder),
3003 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3004 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3008 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3009 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3011 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3012 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3016 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3018 PlaceBase::Local(local) => local.visit_with(visitor),
3019 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3024 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3025 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3026 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3027 folder.tcx().intern_place_elems(&v)
3030 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3031 self.iter().any(|t| t.visit_with(visitor))
3035 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3036 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3038 ty: self.ty.fold_with(folder),
3039 kind: self.kind.fold_with(folder),
3040 def_id: self.def_id,
3044 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3045 let Static { ty, kind, def_id: _ } = self;
3047 ty.visit_with(visitor) || kind.visit_with(visitor)
3051 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3052 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3054 StaticKind::Promoted(promoted, substs) =>
3055 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3056 StaticKind::Static => StaticKind::Static
3060 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3062 StaticKind::Promoted(promoted, substs) =>
3063 promoted.visit_with(visitor) || substs.visit_with(visitor),
3064 StaticKind::Static => { false }
3069 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3070 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3071 use crate::mir::Rvalue::*;
3073 Use(ref op) => Use(op.fold_with(folder)),
3074 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3075 Ref(region, bk, ref place) => {
3076 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3078 Len(ref place) => Len(place.fold_with(folder)),
3079 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3080 BinaryOp(op, ref rhs, ref lhs) => {
3081 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3083 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3084 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3086 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3087 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3088 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3089 Aggregate(ref kind, ref fields) => {
3090 let kind = box match **kind {
3091 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3092 AggregateKind::Tuple => AggregateKind::Tuple,
3093 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3096 substs.fold_with(folder),
3097 user_ty.fold_with(folder),
3100 AggregateKind::Closure(id, substs) => {
3101 AggregateKind::Closure(id, substs.fold_with(folder))
3103 AggregateKind::Generator(id, substs, movablity) => {
3104 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3107 Aggregate(kind, fields.fold_with(folder))
3112 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3113 use crate::mir::Rvalue::*;
3115 Use(ref op) => op.visit_with(visitor),
3116 Repeat(ref op, _) => op.visit_with(visitor),
3117 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3118 Len(ref place) => place.visit_with(visitor),
3119 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3120 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3121 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3123 UnaryOp(_, ref val) => val.visit_with(visitor),
3124 Discriminant(ref place) => place.visit_with(visitor),
3125 NullaryOp(_, ty) => ty.visit_with(visitor),
3126 Aggregate(ref kind, ref fields) => {
3128 AggregateKind::Array(ty) => ty.visit_with(visitor),
3129 AggregateKind::Tuple => false,
3130 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3131 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3133 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3134 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3135 }) || fields.visit_with(visitor)
3141 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3142 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3144 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3145 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3146 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3150 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3152 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3153 Operand::Constant(ref c) => c.visit_with(visitor),
3158 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3159 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3160 use crate::mir::ProjectionElem::*;
3164 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3165 Index(v) => Index(v.fold_with(folder)),
3166 elem => elem.clone(),
3170 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3171 use crate::mir::ProjectionElem::*;
3174 Field(_, ty) => ty.visit_with(visitor),
3175 Index(v) => v.visit_with(visitor),
3181 impl<'tcx> TypeFoldable<'tcx> for Field {
3182 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3185 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3190 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3191 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3194 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3199 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3200 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3203 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3208 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3209 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3211 span: self.span.clone(),
3212 user_ty: self.user_ty.fold_with(folder),
3213 literal: self.literal.fold_with(folder),
3216 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3217 self.literal.visit_with(visitor)