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, InlineAsm as HirInlineAsm};
10 use crate::mir::interpret::{ConstValue, 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, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
19 UserTypeAnnotationIndex,
22 use polonius_engine::Atom;
23 use rustc_data_structures::bit_set::BitMatrix;
24 use rustc_data_structures::fx::FxHashSet;
25 use rustc_data_structures::graph::dominators::{dominators, Dominators};
26 use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
27 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
28 use rustc_data_structures::sync::Lrc;
29 use rustc_data_structures::sync::MappedReadGuard;
30 use rustc_macros::HashStable;
31 use rustc_serialize::{Encodable, Decodable};
32 use smallvec::SmallVec;
34 use std::fmt::{self, Debug, Display, Formatter, Write};
35 use std::ops::{Index, IndexMut};
37 use std::vec::IntoIter;
38 use std::{iter, mem, option, u32};
39 use syntax::ast::Name;
40 use syntax::symbol::{InternedString, Symbol};
41 use syntax_pos::{Span, DUMMY_SP};
43 pub use crate::mir::interpret::AssertMessage;
53 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
55 pub trait HasLocalDecls<'tcx> {
56 fn local_decls(&self) -> &LocalDecls<'tcx>;
59 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
60 fn local_decls(&self) -> &LocalDecls<'tcx> {
65 impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
66 fn local_decls(&self) -> &LocalDecls<'tcx> {
71 /// The various "big phases" that MIR goes through.
73 /// Warning: ordering of variants is significant.
74 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, 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)]
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 /// Crate-local information for each source scope, that can't (and
108 /// needn't) be tracked across crates.
109 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
111 /// The yield type of the function, if it is a generator.
112 pub yield_ty: Option<Ty<'tcx>>,
114 /// Generator drop glue.
115 pub generator_drop: Option<Box<Body<'tcx>>>,
117 /// The layout of a generator. Produced by the state transformation.
118 pub generator_layout: Option<GeneratorLayout<'tcx>>,
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 /// Names and capture modes of all the closure upvars, assuming
145 /// the first argument is either the closure or a reference to it.
147 // NOTE(eddyb) This is *strictly* a temporary hack for codegen
148 // debuginfo generation, and will be removed at some point.
149 // Do **NOT** use it for anything else; upvar information should not be
150 // in the MIR, so please rely on local crate HIR or other side-channels.
151 pub __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
153 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
154 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
155 /// this conversion from happening and use short circuiting, we will cause the following code
156 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
158 /// List of places where control flow was destroyed. Used for error reporting.
159 pub control_flow_destroyed: Vec<(Span, String)>,
161 /// A span representing this MIR, for error reporting.
164 /// A cache for various calculations.
168 impl<'tcx> Body<'tcx> {
170 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
171 source_scopes: IndexVec<SourceScope, SourceScopeData>,
172 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
173 yield_ty: Option<Ty<'tcx>>,
174 local_decls: LocalDecls<'tcx>,
175 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
177 __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
179 control_flow_destroyed: Vec<(Span, String)>,
181 // We need `arg_count` locals, and one for the return place.
183 local_decls.len() >= arg_count + 1,
184 "expected at least {} locals, got {}",
190 phase: MirPhase::Build,
193 source_scope_local_data,
195 generator_drop: None,
196 generator_layout: None,
198 user_type_annotations,
200 __upvar_debuginfo_codegen_only_do_not_use,
203 cache: cache::Cache::new(),
204 control_flow_destroyed,
209 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
214 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
215 self.cache.invalidate();
216 &mut self.basic_blocks
220 pub fn basic_blocks_and_local_decls_mut(
222 ) -> (&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>, &mut LocalDecls<'tcx>) {
223 self.cache.invalidate();
224 (&mut self.basic_blocks, &mut self.local_decls)
228 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
229 self.cache.predecessors(self)
233 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
234 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
238 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
239 let if_zero_locations = if loc.statement_index == 0 {
240 let predecessor_blocks = self.predecessors_for(loc.block);
241 let num_predecessor_blocks = predecessor_blocks.len();
243 (0..num_predecessor_blocks)
244 .map(move |i| predecessor_blocks[i])
245 .map(move |bb| self.terminator_loc(bb)),
251 let if_not_zero_locations = if loc.statement_index == 0 {
254 Some(Location { block: loc.block, statement_index: loc.statement_index - 1 })
257 if_zero_locations.into_iter().flatten().chain(if_not_zero_locations)
261 pub fn dominators(&self) -> Dominators<BasicBlock> {
266 pub fn local_kind(&self, local: Local) -> LocalKind {
267 let index = local.as_usize();
270 self.local_decls[local].mutability == Mutability::Mut,
271 "return place should be mutable"
274 LocalKind::ReturnPointer
275 } else if index < self.arg_count + 1 {
277 } else if self.local_decls[local].name.is_some() {
284 /// Returns an iterator over all temporaries.
286 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
287 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
288 let local = Local::new(index);
289 if self.local_decls[local].is_user_variable.is_some() {
297 /// Returns an iterator over all user-declared locals.
299 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
300 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
301 let local = Local::new(index);
302 if self.local_decls[local].is_user_variable.is_some() {
310 /// Returns an iterator over all user-declared mutable locals.
312 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
313 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
314 let local = Local::new(index);
315 let decl = &self.local_decls[local];
316 if decl.is_user_variable.is_some() && decl.mutability == Mutability::Mut {
324 /// Returns an iterator over all user-declared mutable arguments and locals.
326 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
327 (1..self.local_decls.len()).filter_map(move |index| {
328 let local = Local::new(index);
329 let decl = &self.local_decls[local];
330 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
331 && decl.mutability == Mutability::Mut
340 /// Returns an iterator over all function arguments.
342 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
343 let arg_count = self.arg_count;
344 (1..=arg_count).map(Local::new)
347 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
348 /// locals that are neither arguments nor the return place).
350 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
351 let arg_count = self.arg_count;
352 let local_count = self.local_decls.len();
353 (arg_count + 1..local_count).map(Local::new)
356 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
357 /// invalidating statement indices in `Location`s.
358 pub fn make_statement_nop(&mut self, location: Location) {
359 let block = &mut self[location.block];
360 debug_assert!(location.statement_index < block.statements.len());
361 block.statements[location.statement_index].make_nop()
364 /// Returns the source info associated with `location`.
365 pub fn source_info(&self, location: Location) -> &SourceInfo {
366 let block = &self[location.block];
367 let stmts = &block.statements;
368 let idx = location.statement_index;
369 if idx < stmts.len() {
370 &stmts[idx].source_info
372 assert_eq!(idx, stmts.len());
373 &block.terminator().source_info
377 /// Checks if `sub` is a sub scope of `sup`
378 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
380 match self.source_scopes[sub].parent_scope {
381 None => return false,
388 /// Returns the return type; it always return first element from `local_decls` array.
389 pub fn return_ty(&self) -> Ty<'tcx> {
390 self.local_decls[RETURN_PLACE].ty
393 /// Gets the location of the terminator for the given block.
394 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
395 Location { block: bb, statement_index: self[bb].statements.len() }
399 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
402 /// Unsafe because of a PushUnsafeBlock
404 /// Unsafe because of an unsafe fn
406 /// Unsafe because of an `unsafe` block
407 ExplicitUnsafe(hir::HirId),
410 impl_stable_hash_for!(struct Body<'tcx> {
414 source_scope_local_data,
419 user_type_annotations,
421 __upvar_debuginfo_codegen_only_do_not_use,
423 control_flow_destroyed,
428 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
429 type Output = BasicBlockData<'tcx>;
432 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
433 &self.basic_blocks()[index]
437 impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
439 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
440 &mut self.basic_blocks_mut()[index]
444 #[derive(Copy, Clone, Debug, HashStable)]
445 pub enum ClearCrossCrate<T> {
450 impl<T> ClearCrossCrate<T> {
451 pub fn assert_crate_local(self) -> T {
453 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
454 ClearCrossCrate::Set(v) => v,
459 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
460 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
462 /// Grouped information about the source code origin of a MIR entity.
463 /// Intended to be inspected by diagnostics and debuginfo.
464 /// Most passes can work with it as a whole, within a single function.
465 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, HashStable)]
466 pub struct SourceInfo {
467 /// The source span for the AST pertaining to this MIR entity.
470 /// The source scope, keeping track of which bindings can be
471 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
472 pub scope: SourceScope,
475 ///////////////////////////////////////////////////////////////////////////
476 // Mutability and borrow kinds
478 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
479 pub enum Mutability {
484 impl From<Mutability> for hir::Mutability {
485 fn from(m: Mutability) -> Self {
487 Mutability::Mut => hir::MutMutable,
488 Mutability::Not => hir::MutImmutable,
494 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
496 pub enum BorrowKind {
497 /// Data must be immutable and is aliasable.
500 /// The immediately borrowed place must be immutable, but projections from
501 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
502 /// conflict with a mutable borrow of `a.b.c`.
504 /// This is used when lowering matches: when matching on a place we want to
505 /// ensure that place have the same value from the start of the match until
506 /// an arm is selected. This prevents this code from compiling:
508 /// let mut x = &Some(0);
511 /// Some(_) if { x = &None; false } => (),
515 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
516 /// should not prevent `if let None = x { ... }`, for example, because the
517 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
518 /// We can also report errors with this kind of borrow differently.
521 /// Data must be immutable but not aliasable. This kind of borrow
522 /// cannot currently be expressed by the user and is used only in
523 /// implicit closure bindings. It is needed when the closure is
524 /// borrowing or mutating a mutable referent, e.g.:
526 /// let x: &mut isize = ...;
527 /// let y = || *x += 5;
529 /// If we were to try to translate this closure into a more explicit
530 /// form, we'd encounter an error with the code as written:
532 /// struct Env { x: & &mut isize }
533 /// let x: &mut isize = ...;
534 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
535 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
537 /// This is then illegal because you cannot mutate an `&mut` found
538 /// in an aliasable location. To solve, you'd have to translate with
539 /// an `&mut` borrow:
541 /// struct Env { x: & &mut isize }
542 /// let x: &mut isize = ...;
543 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
544 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
546 /// Now the assignment to `**env.x` is legal, but creating a
547 /// mutable pointer to `x` is not because `x` is not mutable. We
548 /// could fix this by declaring `x` as `let mut x`. This is ok in
549 /// user code, if awkward, but extra weird for closures, since the
550 /// borrow is hidden.
552 /// So we introduce a "unique imm" borrow -- the referent is
553 /// immutable, but not aliasable. This solves the problem. For
554 /// simplicity, we don't give users the way to express this
555 /// borrow, it's just used when translating closures.
558 /// Data is mutable and not aliasable.
560 /// `true` if this borrow arose from method-call auto-ref
561 /// (i.e., `adjustment::Adjust::Borrow`).
562 allow_two_phase_borrow: bool,
567 pub fn allows_two_phase_borrow(&self) -> bool {
569 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
570 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
575 ///////////////////////////////////////////////////////////////////////////
576 // Variables and temps
581 DEBUG_FORMAT = "_{}",
582 const RETURN_PLACE = 0,
586 impl Atom for Local {
587 fn index(self) -> usize {
592 /// Classifies locals into categories. See `Body::local_kind`.
593 #[derive(PartialEq, Eq, Debug, HashStable)]
595 /// User-declared variable binding.
597 /// Compiler-introduced temporary.
599 /// Function argument.
601 /// Location of function's return value.
605 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
606 pub struct VarBindingForm<'tcx> {
607 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
608 pub binding_mode: ty::BindingMode,
609 /// If an explicit type was provided for this variable binding,
610 /// this holds the source Span of that type.
612 /// NOTE: if you want to change this to a `HirId`, be wary that
613 /// doing so breaks incremental compilation (as of this writing),
614 /// while a `Span` does not cause our tests to fail.
615 pub opt_ty_info: Option<Span>,
616 /// Place of the RHS of the =, or the subject of the `match` where this
617 /// variable is initialized. None in the case of `let PATTERN;`.
618 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
619 /// (a) the right-hand side isn't evaluated as a place expression.
620 /// (b) it gives a way to separate this case from the remaining cases
622 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
623 /// The span of the pattern in which this variable was bound.
627 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
628 pub enum BindingForm<'tcx> {
629 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
630 Var(VarBindingForm<'tcx>),
631 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
632 ImplicitSelf(ImplicitSelfKind),
633 /// Reference used in a guard expression to ensure immutability.
637 /// Represents what type of implicit self a function has, if any.
638 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
639 pub enum ImplicitSelfKind {
640 /// Represents a `fn x(self);`.
642 /// Represents a `fn x(mut self);`.
644 /// Represents a `fn x(&self);`.
646 /// Represents a `fn x(&mut self);`.
648 /// Represents when a function does not have a self argument or
649 /// when a function has a `self: X` argument.
653 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
655 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
662 impl_stable_hash_for!(enum self::ImplicitSelfKind {
670 impl_stable_hash_for!(enum self::MirPhase {
677 mod binding_form_impl {
678 use crate::ich::StableHashingContext;
679 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
681 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
682 fn hash_stable<W: StableHasherResult>(
684 hcx: &mut StableHashingContext<'a>,
685 hasher: &mut StableHasher<W>,
687 use super::BindingForm::*;
688 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
691 Var(binding) => binding.hash_stable(hcx, hasher),
692 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
699 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
700 /// created during evaluation of expressions in a block tail
701 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
703 /// It is used to improve diagnostics when such temporaries are
704 /// involved in borrow_check errors, e.g., explanations of where the
705 /// temporaries come from, when their destructors are run, and/or how
706 /// one might revise the code to satisfy the borrow checker's rules.
707 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
708 pub struct BlockTailInfo {
709 /// If `true`, then the value resulting from evaluating this tail
710 /// expression is ignored by the block's expression context.
712 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
713 /// but not e.g., `let _x = { ...; tail };`
714 pub tail_result_is_ignored: bool,
717 impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
721 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
722 /// argument, or the return place.
723 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
724 pub struct LocalDecl<'tcx> {
725 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
727 /// Temporaries and the return place are always mutable.
728 pub mutability: Mutability,
730 /// `Some(binding_mode)` if this corresponds to a user-declared local variable.
732 /// This is solely used for local diagnostics when generating
733 /// warnings/errors when compiling the current crate, and
734 /// therefore it need not be visible across crates. pnkfelix
735 /// currently hypothesized we *need* to wrap this in a
736 /// `ClearCrossCrate` as long as it carries as `HirId`.
737 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
739 /// `true` if this is an internal local.
741 /// These locals are not based on types in the source code and are only used
742 /// for a few desugarings at the moment.
744 /// The generator transformation will sanity check the locals which are live
745 /// across a suspension point against the type components of the generator
746 /// which type checking knows are live across a suspension point. We need to
747 /// flag drop flags to avoid triggering this check as they are introduced
750 /// Unsafety checking will also ignore dereferences of these locals,
751 /// so they can be used for raw pointers only used in a desugaring.
753 /// This should be sound because the drop flags are fully algebraic, and
754 /// therefore don't affect the OIBIT or outlives properties of the
758 /// If this local is a temporary and `is_block_tail` is `Some`,
759 /// then it is a temporary created for evaluation of some
760 /// subexpression of some block's tail expression (with no
761 /// intervening statement context).
762 pub is_block_tail: Option<BlockTailInfo>,
764 /// The type of this local.
767 /// If the user manually ascribed a type to this variable,
768 /// e.g., via `let x: T`, then we carry that type here. The MIR
769 /// borrow checker needs this information since it can affect
770 /// region inference.
771 pub user_ty: UserTypeProjections,
773 /// The name of the local, used in debuginfo and pretty-printing.
775 /// Note that function arguments can also have this set to `Some(_)`
776 /// to generate better debuginfo.
777 pub name: Option<Name>,
779 /// The *syntactic* (i.e., not visibility) source scope the local is defined
780 /// in. If the local was defined in a let-statement, this
781 /// is *within* the let-statement, rather than outside
784 /// This is needed because the visibility source scope of locals within
785 /// a let-statement is weird.
787 /// The reason is that we want the local to be *within* the let-statement
788 /// for lint purposes, but we want the local to be *after* the let-statement
789 /// for names-in-scope purposes.
791 /// That's it, if we have a let-statement like the one in this
795 /// fn foo(x: &str) {
796 /// #[allow(unused_mut)]
797 /// let mut x: u32 = { // <- one unused mut
798 /// let mut y: u32 = x.parse().unwrap();
805 /// Then, from a lint point of view, the declaration of `x: u32`
806 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
807 /// lint scopes are the same as the AST/HIR nesting.
809 /// However, from a name lookup point of view, the scopes look more like
810 /// as if the let-statements were `match` expressions:
813 /// fn foo(x: &str) {
815 /// match x.parse().unwrap() {
824 /// We care about the name-lookup scopes for debuginfo - if the
825 /// debuginfo instruction pointer is at the call to `x.parse()`, we
826 /// want `x` to refer to `x: &str`, but if it is at the call to
827 /// `drop(x)`, we want it to refer to `x: u32`.
829 /// To allow both uses to work, we need to have more than a single scope
830 /// for a local. We have the `source_info.scope` represent the
831 /// "syntactic" lint scope (with a variable being under its let
832 /// block) while the `visibility_scope` represents the "local variable"
833 /// scope (where the "rest" of a block is under all prior let-statements).
835 /// The end result looks like this:
839 /// │{ argument x: &str }
841 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
842 /// │ │ // in practice because I'm lazy.
844 /// │ │← x.source_info.scope
845 /// │ │← `x.parse().unwrap()`
847 /// │ │ │← y.source_info.scope
849 /// │ │ │{ let y: u32 }
851 /// │ │ │← y.visibility_scope
854 /// │ │{ let x: u32 }
855 /// │ │← x.visibility_scope
856 /// │ │← `drop(x)` // This accesses `x: u32`.
858 pub source_info: SourceInfo,
860 /// Source scope within which the local is visible (for debuginfo)
861 /// (see `source_info` for more details).
862 pub visibility_scope: SourceScope,
865 impl<'tcx> LocalDecl<'tcx> {
866 /// Returns `true` only if local is a binding that can itself be
867 /// made mutable via the addition of the `mut` keyword, namely
868 /// something like the occurrences of `x` in:
869 /// - `fn foo(x: Type) { ... }`,
871 /// - or `match ... { C(x) => ... }`
872 pub fn can_be_made_mutable(&self) -> bool {
873 match self.is_user_variable {
874 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
875 binding_mode: ty::BindingMode::BindByValue(_),
881 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm))) => true,
887 /// Returns `true` if local is definitely not a `ref ident` or
888 /// `ref mut ident` binding. (Such bindings cannot be made into
889 /// mutable bindings, but the inverse does not necessarily hold).
890 pub fn is_nonref_binding(&self) -> bool {
891 match self.is_user_variable {
892 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
893 binding_mode: ty::BindingMode::BindByValue(_),
899 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
905 /// Returns `true` if this is a reference to a variable bound in a `match`
906 /// expression that is used to access said variable for the guard of the
908 pub fn is_ref_for_guard(&self) -> bool {
909 match self.is_user_variable {
910 Some(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
915 /// Returns `true` is the local is from a compiler desugaring, e.g.,
916 /// `__next` from a `for` loop.
918 pub fn from_compiler_desugaring(&self) -> bool {
919 self.source_info.span.desugaring_kind().is_some()
922 /// Creates a new `LocalDecl` for a temporary.
924 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
925 Self::new_local(ty, Mutability::Mut, false, span)
928 /// Converts `self` into same `LocalDecl` except tagged as immutable.
930 pub fn immutable(mut self) -> Self {
931 self.mutability = Mutability::Not;
935 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
937 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
938 assert!(self.is_block_tail.is_none());
939 self.is_block_tail = Some(info);
943 /// Creates a new `LocalDecl` for a internal temporary.
945 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
946 Self::new_local(ty, Mutability::Mut, true, span)
950 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
954 user_ty: UserTypeProjections::none(),
956 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
957 visibility_scope: OUTERMOST_SOURCE_SCOPE,
959 is_user_variable: None,
964 /// Builds a `LocalDecl` for the return place.
966 /// This must be inserted into the `local_decls` list as the first local.
968 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
970 mutability: Mutability::Mut,
972 user_ty: UserTypeProjections::none(),
973 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
974 visibility_scope: OUTERMOST_SOURCE_SCOPE,
977 name: None, // FIXME maybe we do want some name here?
978 is_user_variable: None,
983 /// A closure capture, with its name and mode.
984 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
985 pub struct UpvarDebuginfo {
986 pub debug_name: Name,
988 /// If true, the capture is behind a reference.
992 ///////////////////////////////////////////////////////////////////////////
996 pub struct BasicBlock {
998 DEBUG_FORMAT = "bb{}",
999 const START_BLOCK = 0,
1004 pub fn start_location(self) -> Location {
1005 Location { block: self, statement_index: 0 }
1009 ///////////////////////////////////////////////////////////////////////////
1010 // BasicBlockData and Terminator
1012 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1013 pub struct BasicBlockData<'tcx> {
1014 /// List of statements in this block.
1015 pub statements: Vec<Statement<'tcx>>,
1017 /// Terminator for this block.
1019 /// N.B., this should generally ONLY be `None` during construction.
1020 /// Therefore, you should generally access it via the
1021 /// `terminator()` or `terminator_mut()` methods. The only
1022 /// exception is that certain passes, such as `simplify_cfg`, swap
1023 /// out the terminator temporarily with `None` while they continue
1024 /// to recurse over the set of basic blocks.
1025 pub terminator: Option<Terminator<'tcx>>,
1027 /// If true, this block lies on an unwind path. This is used
1028 /// during codegen where distinct kinds of basic blocks may be
1029 /// generated (particularly for MSVC cleanup). Unwind blocks must
1030 /// only branch to other unwind blocks.
1031 pub is_cleanup: bool,
1034 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1035 pub struct Terminator<'tcx> {
1036 pub source_info: SourceInfo,
1037 pub kind: TerminatorKind<'tcx>,
1040 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1041 pub enum TerminatorKind<'tcx> {
1042 /// Block should have one successor in the graph; we jump there.
1043 Goto { target: BasicBlock },
1045 /// Operand evaluates to an integer; jump depending on its value
1046 /// to one of the targets, and otherwise fallback to `otherwise`.
1048 /// The discriminant value being tested.
1049 discr: Operand<'tcx>,
1051 /// The type of value being tested.
1052 switch_ty: Ty<'tcx>,
1054 /// Possible values. The locations to branch to in each case
1055 /// are found in the corresponding indices from the `targets` vector.
1056 values: Cow<'tcx, [u128]>,
1058 /// Possible branch sites. The last element of this vector is used
1059 /// for the otherwise branch, so targets.len() == values.len() + 1
1062 // This invariant is quite non-obvious and also could be improved.
1063 // One way to make this invariant is to have something like this instead:
1065 // branches: Vec<(ConstInt, BasicBlock)>,
1066 // otherwise: Option<BasicBlock> // exhaustive if None
1068 // However we’ve decided to keep this as-is until we figure a case
1069 // where some other approach seems to be strictly better than other.
1070 targets: Vec<BasicBlock>,
1073 /// Indicates that the landing pad is finished and unwinding should
1074 /// continue. Emitted by `build::scope::diverge_cleanup`.
1077 /// Indicates that the landing pad is finished and that the process
1078 /// should abort. Used to prevent unwinding for foreign items.
1081 /// Indicates a normal return. The return place should have
1082 /// been filled in by now. This should occur at most once.
1085 /// Indicates a terminator that can never be reached.
1088 /// Drop the `Place`.
1089 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1091 /// Drop the `Place` and assign the new value over it. This ensures
1092 /// that the assignment to `P` occurs *even if* the destructor for
1093 /// place unwinds. Its semantics are best explained by the
1098 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1106 /// Drop(P, goto BB1, unwind BB2)
1109 /// // P is now uninitialized
1113 /// // P is now uninitialized -- its dtor panicked
1118 location: Place<'tcx>,
1119 value: Operand<'tcx>,
1121 unwind: Option<BasicBlock>,
1124 /// Block ends with a call of a converging function.
1126 /// The function that’s being called.
1127 func: Operand<'tcx>,
1128 /// Arguments the function is called with.
1129 /// These are owned by the callee, which is free to modify them.
1130 /// This allows the memory occupied by "by-value" arguments to be
1131 /// reused across function calls without duplicating the contents.
1132 args: Vec<Operand<'tcx>>,
1133 /// Destination for the return value. If some, the call is converging.
1134 destination: Option<(Place<'tcx>, BasicBlock)>,
1135 /// Cleanups to be done if the call unwinds.
1136 cleanup: Option<BasicBlock>,
1137 /// `true` if this is from a call in HIR rather than from an overloaded
1138 /// operator. True for overloaded function call.
1139 from_hir_call: bool,
1142 /// Jump to the target if the condition has the expected value,
1143 /// otherwise panic with a message and a cleanup target.
1145 cond: Operand<'tcx>,
1147 msg: AssertMessage<'tcx>,
1149 cleanup: Option<BasicBlock>,
1152 /// A suspend point.
1154 /// The value to return.
1155 value: Operand<'tcx>,
1156 /// Where to resume to.
1158 /// Cleanup to be done if the generator is dropped at this suspend point.
1159 drop: Option<BasicBlock>,
1162 /// Indicates the end of the dropping of a generator.
1165 /// A block where control flow only ever takes one real path, but borrowck
1166 /// needs to be more conservative.
1168 /// The target normal control flow will take.
1169 real_target: BasicBlock,
1170 /// A block control flow could conceptually jump to, but won't in
1172 imaginary_target: BasicBlock,
1174 /// A terminator for blocks that only take one path in reality, but where we
1175 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1176 /// This can arise in infinite loops with no function calls for example.
1178 /// The target normal control flow will take.
1179 real_target: BasicBlock,
1180 /// The imaginary cleanup block link. This particular path will never be taken
1181 /// in practice, but in order to avoid fragility we want to always
1182 /// consider it in borrowck. We don't want to accept programs which
1183 /// pass borrowck only when `panic=abort` or some assertions are disabled
1184 /// due to release vs. debug mode builds. This needs to be an `Option` because
1185 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1186 unwind: Option<BasicBlock>,
1190 pub type Successors<'a> =
1191 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1192 pub type SuccessorsMut<'a> =
1193 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1195 impl<'tcx> Terminator<'tcx> {
1196 pub fn successors(&self) -> Successors<'_> {
1197 self.kind.successors()
1200 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1201 self.kind.successors_mut()
1204 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1208 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1209 self.kind.unwind_mut()
1213 impl<'tcx> TerminatorKind<'tcx> {
1216 cond: Operand<'tcx>,
1219 ) -> TerminatorKind<'tcx> {
1220 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1221 TerminatorKind::SwitchInt {
1223 switch_ty: tcx.types.bool,
1224 values: From::from(BOOL_SWITCH_FALSE),
1225 targets: vec![f, t],
1229 pub fn successors(&self) -> Successors<'_> {
1230 use self::TerminatorKind::*;
1237 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1238 Goto { target: ref t }
1239 | Call { destination: None, cleanup: Some(ref t), .. }
1240 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1241 | Yield { resume: ref t, drop: None, .. }
1242 | DropAndReplace { target: ref t, unwind: None, .. }
1243 | Drop { target: ref t, unwind: None, .. }
1244 | Assert { target: ref t, cleanup: None, .. }
1245 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1246 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1247 | Yield { resume: ref t, drop: Some(ref u), .. }
1248 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1249 | Drop { target: ref t, unwind: Some(ref u), .. }
1250 | Assert { target: ref t, cleanup: Some(ref u), .. }
1251 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1252 Some(t).into_iter().chain(slice::from_ref(u))
1254 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1255 FalseEdges { ref real_target, ref imaginary_target } => {
1256 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1261 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1262 use self::TerminatorKind::*;
1269 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1270 Goto { target: ref mut t }
1271 | Call { destination: None, cleanup: Some(ref mut t), .. }
1272 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1273 | Yield { resume: ref mut t, drop: None, .. }
1274 | DropAndReplace { target: ref mut t, unwind: None, .. }
1275 | Drop { target: ref mut t, unwind: None, .. }
1276 | Assert { target: ref mut t, cleanup: None, .. }
1277 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1278 Some(t).into_iter().chain(&mut [])
1280 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1281 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1282 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1283 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1284 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1285 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1286 Some(t).into_iter().chain(slice::from_mut(u))
1288 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1289 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1290 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1295 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1297 TerminatorKind::Goto { .. }
1298 | TerminatorKind::Resume
1299 | TerminatorKind::Abort
1300 | TerminatorKind::Return
1301 | TerminatorKind::Unreachable
1302 | TerminatorKind::GeneratorDrop
1303 | TerminatorKind::Yield { .. }
1304 | TerminatorKind::SwitchInt { .. }
1305 | TerminatorKind::FalseEdges { .. } => None,
1306 TerminatorKind::Call { cleanup: ref unwind, .. }
1307 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1308 | TerminatorKind::DropAndReplace { ref unwind, .. }
1309 | TerminatorKind::Drop { ref unwind, .. }
1310 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1314 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1316 TerminatorKind::Goto { .. }
1317 | TerminatorKind::Resume
1318 | TerminatorKind::Abort
1319 | TerminatorKind::Return
1320 | TerminatorKind::Unreachable
1321 | TerminatorKind::GeneratorDrop
1322 | TerminatorKind::Yield { .. }
1323 | TerminatorKind::SwitchInt { .. }
1324 | TerminatorKind::FalseEdges { .. } => None,
1325 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1326 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1327 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1328 | TerminatorKind::Drop { ref mut unwind, .. }
1329 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1334 impl<'tcx> BasicBlockData<'tcx> {
1335 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1336 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1339 /// Accessor for terminator.
1341 /// Terminator may not be None after construction of the basic block is complete. This accessor
1342 /// provides a convenience way to reach the terminator.
1343 pub fn terminator(&self) -> &Terminator<'tcx> {
1344 self.terminator.as_ref().expect("invalid terminator state")
1347 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1348 self.terminator.as_mut().expect("invalid terminator state")
1351 pub fn retain_statements<F>(&mut self, mut f: F)
1353 F: FnMut(&mut Statement<'_>) -> bool,
1355 for s in &mut self.statements {
1362 pub fn expand_statements<F, I>(&mut self, mut f: F)
1364 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1365 I: iter::TrustedLen<Item = Statement<'tcx>>,
1367 // Gather all the iterators we'll need to splice in, and their positions.
1368 let mut splices: Vec<(usize, I)> = vec![];
1369 let mut extra_stmts = 0;
1370 for (i, s) in self.statements.iter_mut().enumerate() {
1371 if let Some(mut new_stmts) = f(s) {
1372 if let Some(first) = new_stmts.next() {
1373 // We can already store the first new statement.
1376 // Save the other statements for optimized splicing.
1377 let remaining = new_stmts.size_hint().0;
1379 splices.push((i + 1 + extra_stmts, new_stmts));
1380 extra_stmts += remaining;
1388 // Splice in the new statements, from the end of the block.
1389 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1390 // where a range of elements ("gap") is left uninitialized, with
1391 // splicing adding new elements to the end of that gap and moving
1392 // existing elements from before the gap to the end of the gap.
1393 // For now, this is safe code, emulating a gap but initializing it.
1394 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1395 self.statements.resize(
1398 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1399 kind: StatementKind::Nop,
1402 for (splice_start, new_stmts) in splices.into_iter().rev() {
1403 let splice_end = splice_start + new_stmts.size_hint().0;
1404 while gap.end > splice_end {
1407 self.statements.swap(gap.start, gap.end);
1409 self.statements.splice(splice_start..splice_end, new_stmts);
1410 gap.end = splice_start;
1414 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1415 if index < self.statements.len() {
1416 &self.statements[index]
1423 impl<'tcx> Debug for TerminatorKind<'tcx> {
1424 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1425 self.fmt_head(fmt)?;
1426 let successor_count = self.successors().count();
1427 let labels = self.fmt_successor_labels();
1428 assert_eq!(successor_count, labels.len());
1430 match successor_count {
1433 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1436 write!(fmt, " -> [")?;
1437 for (i, target) in self.successors().enumerate() {
1441 write!(fmt, "{}: {:?}", labels[i], target)?;
1449 impl<'tcx> TerminatorKind<'tcx> {
1450 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1451 /// successor basic block, if any. The only information not included is the list of possible
1452 /// successors, which may be rendered differently between the text and the graphviz format.
1453 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1454 use self::TerminatorKind::*;
1456 Goto { .. } => write!(fmt, "goto"),
1457 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1458 Return => write!(fmt, "return"),
1459 GeneratorDrop => write!(fmt, "generator_drop"),
1460 Resume => write!(fmt, "resume"),
1461 Abort => write!(fmt, "abort"),
1462 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1463 Unreachable => write!(fmt, "unreachable"),
1464 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1465 DropAndReplace { ref location, ref value, .. } => {
1466 write!(fmt, "replace({:?} <- {:?})", location, value)
1468 Call { ref func, ref args, ref destination, .. } => {
1469 if let Some((ref destination, _)) = *destination {
1470 write!(fmt, "{:?} = ", destination)?;
1472 write!(fmt, "{:?}(", func)?;
1473 for (index, arg) in args.iter().enumerate() {
1477 write!(fmt, "{:?}", arg)?;
1481 Assert { ref cond, expected, ref msg, .. } => {
1482 write!(fmt, "assert(")?;
1486 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1488 FalseEdges { .. } => write!(fmt, "falseEdges"),
1489 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1493 /// Returns the list of labels for the edges to the successor basic blocks.
1494 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1495 use self::TerminatorKind::*;
1497 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1498 Goto { .. } => vec!["".into()],
1499 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1500 let param_env = ty::ParamEnv::empty();
1501 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1502 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1506 tcx.mk_const(ty::Const {
1507 val: ConstValue::Scalar(Scalar::from_uint(u, size).into()),
1513 .chain(iter::once("otherwise".into()))
1516 Call { destination: Some(_), cleanup: Some(_), .. } => {
1517 vec!["return".into(), "unwind".into()]
1519 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1520 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1521 Call { destination: None, cleanup: None, .. } => vec![],
1522 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1523 Yield { drop: None, .. } => vec!["resume".into()],
1524 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1525 vec!["return".into()]
1527 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1528 vec!["return".into(), "unwind".into()]
1530 Assert { cleanup: None, .. } => vec!["".into()],
1531 Assert { .. } => vec!["success".into(), "unwind".into()],
1532 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1533 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1534 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1539 ///////////////////////////////////////////////////////////////////////////
1542 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1543 pub struct Statement<'tcx> {
1544 pub source_info: SourceInfo,
1545 pub kind: StatementKind<'tcx>,
1548 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1549 #[cfg(target_arch = "x86_64")]
1550 static_assert_size!(Statement<'_>, 32);
1552 impl Statement<'_> {
1553 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1554 /// invalidating statement indices in `Location`s.
1555 pub fn make_nop(&mut self) {
1556 self.kind = StatementKind::Nop
1559 /// Changes a statement to a nop and returns the original statement.
1560 pub fn replace_nop(&mut self) -> Self {
1562 source_info: self.source_info,
1563 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1568 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1569 pub enum StatementKind<'tcx> {
1570 /// Write the RHS Rvalue to the LHS Place.
1571 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1573 /// This represents all the reading that a pattern match may do
1574 /// (e.g., inspecting constants and discriminant values), and the
1575 /// kind of pattern it comes from. This is in order to adapt potential
1576 /// error messages to these specific patterns.
1578 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1579 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1580 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1582 /// Write the discriminant for a variant to the enum Place.
1583 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1585 /// Start a live range for the storage of the local.
1588 /// End the current live range for the storage of the local.
1591 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1592 /// of `StatementKind` low.
1593 InlineAsm(Box<InlineAsm<'tcx>>),
1595 /// Retag references in the given place, ensuring they got fresh tags. This is
1596 /// part of the Stacked Borrows model. These statements are currently only interpreted
1597 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1598 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1599 /// for more details.
1600 Retag(RetagKind, Box<Place<'tcx>>),
1602 /// Encodes a user's type ascription. These need to be preserved
1603 /// intact so that NLL can respect them. For example:
1607 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1608 /// to the user-given type `T`. The effect depends on the specified variance:
1610 /// - `Covariant` -- requires that `T_y <: T`
1611 /// - `Contravariant` -- requires that `T_y :> T`
1612 /// - `Invariant` -- requires that `T_y == T`
1613 /// - `Bivariant` -- no effect
1614 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1616 /// No-op. Useful for deleting instructions without affecting statement indices.
1620 /// Describes what kind of retag is to be performed.
1621 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1622 pub enum RetagKind {
1623 /// The initial retag when entering a function.
1625 /// Retag preparing for a two-phase borrow.
1627 /// Retagging raw pointers.
1629 /// A "normal" retag.
1633 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1634 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
1635 pub enum FakeReadCause {
1636 /// Inject a fake read of the borrowed input at the end of each guards
1639 /// This should ensure that you cannot change the variant for an enum while
1640 /// you are in the midst of matching on it.
1643 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1644 /// generate a read of x to check that it is initialized and safe.
1647 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1648 /// in a match guard to ensure that it's value hasn't change by the time
1649 /// we create the OutsideGuard version.
1652 /// Officially, the semantics of
1654 /// `let pattern = <expr>;`
1656 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1657 /// into the pattern.
1659 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1660 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1661 /// but in some cases it can affect the borrow checker, as in #53695.
1662 /// Therefore, we insert a "fake read" here to ensure that we get
1663 /// appropriate errors.
1667 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1668 pub struct InlineAsm<'tcx> {
1669 pub asm: HirInlineAsm,
1670 pub outputs: Box<[Place<'tcx>]>,
1671 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1674 impl Debug for Statement<'_> {
1675 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1676 use self::StatementKind::*;
1678 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1679 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1680 Retag(ref kind, ref place) => write!(
1684 RetagKind::FnEntry => "[fn entry] ",
1685 RetagKind::TwoPhase => "[2phase] ",
1686 RetagKind::Raw => "[raw] ",
1687 RetagKind::Default => "",
1691 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1692 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1693 SetDiscriminant { ref place, variant_index } => {
1694 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1696 InlineAsm(ref asm) => {
1697 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1699 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1700 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1702 Nop => write!(fmt, "nop"),
1707 ///////////////////////////////////////////////////////////////////////////
1710 /// A path to a value; something that can be evaluated without
1711 /// changing or disturbing program state.
1713 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1715 pub struct Place<'tcx> {
1716 pub base: PlaceBase<'tcx>,
1718 /// projection out of a place (access a field, deref a pointer, etc)
1719 pub projection: Box<[PlaceElem<'tcx>]>,
1723 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1725 pub enum PlaceBase<'tcx> {
1729 /// static or static mut variable
1730 Static(Box<Static<'tcx>>),
1733 /// We store the normalized type to avoid requiring normalization when reading MIR
1734 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1735 pub struct Static<'tcx> {
1737 pub kind: StaticKind<'tcx>,
1738 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1739 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1740 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1741 /// into the calling frame.
1746 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1748 pub enum StaticKind<'tcx> {
1749 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1750 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1751 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1752 Promoted(Promoted, SubstsRef<'tcx>),
1756 impl_stable_hash_for!(struct Static<'tcx> {
1763 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1765 pub enum ProjectionElem<V, T> {
1770 /// These indices are generated by slice patterns. Easiest to explain
1774 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1775 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1776 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1777 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1780 /// index or -index (in Python terms), depending on from_end
1782 /// thing being indexed must be at least this long
1784 /// counting backwards from end?
1788 /// These indices are generated by slice patterns.
1790 /// slice[from:-to] in Python terms.
1796 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1797 /// this for ADTs with more than one variant. It may be better to
1798 /// just introduce it always, or always for enums.
1800 /// The included Symbol is the name of the variant, used for printing MIR.
1801 Downcast(Option<Symbol>, VariantIdx),
1804 impl<V, T> ProjectionElem<V, T> {
1805 /// Returns `true` if the target of this projection may refer to a different region of memory
1807 fn is_indirect(&self) -> bool {
1809 Self::Deref => true,
1813 | Self::ConstantIndex { .. }
1814 | Self::Subslice { .. }
1815 | Self::Downcast(_, _)
1821 /// Alias for projections as they appear in places, where the base is a place
1822 /// and the index is a local.
1823 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1825 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1826 #[cfg(target_arch = "x86_64")]
1827 static_assert_size!(PlaceElem<'_>, 16);
1829 /// Alias for projections as they appear in `UserTypeProjection`, where we
1830 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1831 pub type ProjectionKind = ProjectionElem<(), ()>;
1836 DEBUG_FORMAT = "field[{}]"
1840 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1841 pub struct PlaceRef<'a, 'tcx> {
1842 pub base: &'a PlaceBase<'tcx>,
1843 pub projection: &'a [PlaceElem<'tcx>],
1846 impl<'tcx> Place<'tcx> {
1847 // FIXME change this back to a const when projection is a shared slice.
1849 // pub const RETURN_PLACE: Place<'tcx> = Place {
1850 // base: PlaceBase::Local(RETURN_PLACE),
1853 pub fn return_place() -> Place<'tcx> {
1855 base: PlaceBase::Local(RETURN_PLACE),
1856 projection: Box::new([]),
1860 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
1861 self.elem(ProjectionElem::Field(f, ty))
1864 pub fn deref(self) -> Place<'tcx> {
1865 self.elem(ProjectionElem::Deref)
1868 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
1869 self.elem(ProjectionElem::Downcast(
1870 Some(adt_def.variants[variant_index].ident.name),
1875 pub fn downcast_unnamed(self, variant_index: VariantIdx) -> Place<'tcx> {
1876 self.elem(ProjectionElem::Downcast(None, variant_index))
1879 pub fn index(self, index: Local) -> Place<'tcx> {
1880 self.elem(ProjectionElem::Index(index))
1883 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
1884 // FIXME(spastorino): revisit this again once projection is not a Box<[T]> anymore
1885 let mut projection = self.projection.into_vec();
1886 projection.push(elem);
1890 projection: projection.into_boxed_slice(),
1894 /// Returns `true` if this `Place` contains a `Deref` projection.
1896 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1897 /// same region of memory as its base.
1898 pub fn is_indirect(&self) -> bool {
1899 self.projection.iter().any(|elem| elem.is_indirect())
1902 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1903 /// a single deref of a local.
1905 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1906 pub fn local_or_deref_local(&self) -> Option<Local> {
1909 base: PlaceBase::Local(local),
1913 base: PlaceBase::Local(local),
1914 projection: box [ProjectionElem::Deref],
1920 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1923 projection: &self.projection,
1928 impl From<Local> for Place<'_> {
1929 fn from(local: Local) -> Self {
1932 projection: Box::new([]),
1937 impl From<Local> for PlaceBase<'_> {
1938 fn from(local: Local) -> Self {
1939 PlaceBase::Local(local)
1943 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1944 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1945 /// a single deref of a local.
1947 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1948 pub fn local_or_deref_local(&self) -> Option<Local> {
1951 base: PlaceBase::Local(local),
1955 base: PlaceBase::Local(local),
1956 projection: [ProjectionElem::Deref],
1963 impl Debug for Place<'_> {
1964 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1965 for elem in self.projection.iter().rev() {
1967 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1968 write!(fmt, "(").unwrap();
1970 ProjectionElem::Deref => {
1971 write!(fmt, "(*").unwrap();
1973 ProjectionElem::Index(_)
1974 | ProjectionElem::ConstantIndex { .. }
1975 | ProjectionElem::Subslice { .. } => {}
1979 write!(fmt, "{:?}", self.base)?;
1981 for elem in self.projection.iter() {
1983 ProjectionElem::Downcast(Some(name), _index) => {
1984 write!(fmt, " as {})", name)?;
1986 ProjectionElem::Downcast(None, index) => {
1987 write!(fmt, " as variant#{:?})", index)?;
1989 ProjectionElem::Deref => {
1992 ProjectionElem::Field(field, ty) => {
1993 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1995 ProjectionElem::Index(ref index) => {
1996 write!(fmt, "[{:?}]", index)?;
1998 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1999 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
2001 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
2002 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
2004 ProjectionElem::Subslice { from, to } if *to == 0 => {
2005 write!(fmt, "[{:?}:]", from)?;
2007 ProjectionElem::Subslice { from, to } if *from == 0 => {
2008 write!(fmt, "[:-{:?}]", to)?;
2010 ProjectionElem::Subslice { from, to } => {
2011 write!(fmt, "[{:?}:-{:?}]", from, to)?;
2020 impl Debug for PlaceBase<'_> {
2021 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2023 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
2024 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
2025 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
2027 PlaceBase::Static(box self::Static {
2028 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
2030 write!(fmt, "({:?}: {:?})", promoted, ty)
2036 ///////////////////////////////////////////////////////////////////////////
2040 pub struct SourceScope {
2042 DEBUG_FORMAT = "scope[{}]",
2043 const OUTERMOST_SOURCE_SCOPE = 0,
2047 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2048 pub struct SourceScopeData {
2050 pub parent_scope: Option<SourceScope>,
2053 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2054 pub struct SourceScopeLocalData {
2055 /// An `HirId` with lint levels equivalent to this scope's lint levels.
2056 pub lint_root: hir::HirId,
2057 /// The unsafe block that contains this node.
2061 ///////////////////////////////////////////////////////////////////////////
2064 /// These are values that can appear inside an rvalue. They are intentionally
2065 /// limited to prevent rvalues from being nested in one another.
2066 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2067 pub enum Operand<'tcx> {
2068 /// Copy: The value must be available for use afterwards.
2070 /// This implies that the type of the place must be `Copy`; this is true
2071 /// by construction during build, but also checked by the MIR type checker.
2074 /// Move: The value (including old borrows of it) will not be used again.
2076 /// Safe for values of all types (modulo future developments towards `?Move`).
2077 /// Correct usage patterns are enforced by the borrow checker for safe code.
2078 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2081 /// Synthesizes a constant value.
2082 Constant(Box<Constant<'tcx>>),
2085 impl<'tcx> Debug for Operand<'tcx> {
2086 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2087 use self::Operand::*;
2089 Constant(ref a) => write!(fmt, "{:?}", a),
2090 Copy(ref place) => write!(fmt, "{:?}", place),
2091 Move(ref place) => write!(fmt, "move {:?}", place),
2096 impl<'tcx> Operand<'tcx> {
2097 /// Convenience helper to make a constant that refers to the fn
2098 /// with given `DefId` and substs. Since this is used to synthesize
2099 /// MIR, assumes `user_ty` is None.
2100 pub fn function_handle(
2103 substs: SubstsRef<'tcx>,
2106 let ty = tcx.type_of(def_id).subst(tcx, substs);
2107 Operand::Constant(box Constant {
2110 literal: ty::Const::zero_sized(tcx, ty),
2114 pub fn to_copy(&self) -> Self {
2116 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2117 Operand::Move(ref place) => Operand::Copy(place.clone()),
2122 ///////////////////////////////////////////////////////////////////////////
2125 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2126 pub enum Rvalue<'tcx> {
2127 /// x (either a move or copy, depending on type of x)
2131 Repeat(Operand<'tcx>, u64),
2134 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2136 /// length of a [X] or [X;n] value
2139 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2141 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2142 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2144 NullaryOp(NullOp, Ty<'tcx>),
2145 UnaryOp(UnOp, Operand<'tcx>),
2147 /// Read the discriminant of an ADT.
2149 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2150 /// be defined to return, say, a 0) if ADT is not an enum.
2151 Discriminant(Place<'tcx>),
2153 /// Creates an aggregate value, like a tuple or struct. This is
2154 /// only needed because we want to distinguish `dest = Foo { x:
2155 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2156 /// that `Foo` has a destructor. These rvalues can be optimized
2157 /// away after type-checking and before lowering.
2158 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2161 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2164 Pointer(PointerCast),
2167 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2168 pub enum AggregateKind<'tcx> {
2169 /// The type is of the element
2173 /// The second field is the variant index. It's equal to 0 for struct
2174 /// and union expressions. The fourth field is
2175 /// active field number and is present only for union expressions
2176 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2177 /// active field index would identity the field `c`
2178 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2180 Closure(DefId, ClosureSubsts<'tcx>),
2181 Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
2184 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2186 /// The `+` operator (addition)
2188 /// The `-` operator (subtraction)
2190 /// The `*` operator (multiplication)
2192 /// The `/` operator (division)
2194 /// The `%` operator (modulus)
2196 /// The `^` operator (bitwise xor)
2198 /// The `&` operator (bitwise and)
2200 /// The `|` operator (bitwise or)
2202 /// The `<<` operator (shift left)
2204 /// The `>>` operator (shift right)
2206 /// The `==` operator (equality)
2208 /// The `<` operator (less than)
2210 /// The `<=` operator (less than or equal to)
2212 /// The `!=` operator (not equal to)
2214 /// The `>=` operator (greater than or equal to)
2216 /// The `>` operator (greater than)
2218 /// The `ptr.offset` operator
2223 pub fn is_checkable(self) -> bool {
2226 Add | Sub | Mul | Shl | Shr => true,
2232 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2234 /// Returns the size of a value of that type
2236 /// Creates a new uninitialized box for a value of that type
2240 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2242 /// The `!` operator for logical inversion
2244 /// The `-` operator for negation
2248 impl<'tcx> Debug for Rvalue<'tcx> {
2249 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2250 use self::Rvalue::*;
2253 Use(ref place) => write!(fmt, "{:?}", place),
2254 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2255 Len(ref a) => write!(fmt, "Len({:?})", a),
2256 Cast(ref kind, ref place, ref ty) => {
2257 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2259 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2260 CheckedBinaryOp(ref op, ref a, ref b) => {
2261 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2263 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2264 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2265 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2266 Ref(region, borrow_kind, ref place) => {
2267 let kind_str = match borrow_kind {
2268 BorrowKind::Shared => "",
2269 BorrowKind::Shallow => "shallow ",
2270 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2273 // When printing regions, add trailing space if necessary.
2274 let print_region = ty::tls::with(|tcx| {
2275 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2277 let region = if print_region {
2278 let mut region = region.to_string();
2279 if region.len() > 0 {
2284 // Do not even print 'static
2287 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2290 Aggregate(ref kind, ref places) => {
2291 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2292 let mut tuple_fmt = fmt.debug_tuple("");
2293 for place in places {
2294 tuple_fmt.field(place);
2300 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2302 AggregateKind::Tuple => match places.len() {
2303 0 => write!(fmt, "()"),
2304 1 => write!(fmt, "({:?},)", places[0]),
2305 _ => fmt_tuple(fmt, places),
2308 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2309 let variant_def = &adt_def.variants[variant];
2312 ty::tls::with(|tcx| {
2313 let substs = tcx.lift(&substs).expect("could not lift for printing");
2314 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2315 .print_def_path(variant_def.def_id, substs)?;
2319 match variant_def.ctor_kind {
2320 CtorKind::Const => Ok(()),
2321 CtorKind::Fn => fmt_tuple(fmt, places),
2322 CtorKind::Fictive => {
2323 let mut struct_fmt = fmt.debug_struct("");
2324 for (field, place) in variant_def.fields.iter().zip(places) {
2325 struct_fmt.field(&field.ident.as_str(), place);
2332 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2333 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2334 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2335 format!("[closure@{:?}]", hir_id)
2337 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2339 let mut struct_fmt = fmt.debug_struct(&name);
2341 if let Some(upvars) = tcx.upvars(def_id) {
2342 for (&var_id, place) in upvars.keys().zip(places) {
2343 let var_name = tcx.hir().name(var_id);
2344 struct_fmt.field(&var_name.as_str(), place);
2350 write!(fmt, "[closure]")
2354 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2355 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2356 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2357 let mut struct_fmt = fmt.debug_struct(&name);
2359 if let Some(upvars) = tcx.upvars(def_id) {
2360 for (&var_id, place) in upvars.keys().zip(places) {
2361 let var_name = tcx.hir().name(var_id);
2362 struct_fmt.field(&var_name.as_str(), place);
2368 write!(fmt, "[generator]")
2377 ///////////////////////////////////////////////////////////////////////////
2380 /// Two constants are equal if they are the same constant. Note that
2381 /// this does not necessarily mean that they are "==" in Rust -- in
2382 /// particular one must be wary of `NaN`!
2384 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2385 pub struct Constant<'tcx> {
2388 /// Optional user-given type: for something like
2389 /// `collect::<Vec<_>>`, this would be present and would
2390 /// indicate that `Vec<_>` was explicitly specified.
2392 /// Needed for NLL to impose user-given type constraints.
2393 pub user_ty: Option<UserTypeAnnotationIndex>,
2395 pub literal: &'tcx ty::Const<'tcx>,
2398 /// A collection of projections into user types.
2400 /// They are projections because a binding can occur a part of a
2401 /// parent pattern that has been ascribed a type.
2403 /// Its a collection because there can be multiple type ascriptions on
2404 /// the path from the root of the pattern down to the binding itself.
2409 /// struct S<'a>((i32, &'a str), String);
2410 /// let S((_, w): (i32, &'static str), _): S = ...;
2411 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2412 /// // --------------------------------- ^ (2)
2415 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2416 /// ascribed the type `(i32, &'static str)`.
2418 /// The highlights labelled `(2)` show the whole pattern being
2419 /// ascribed the type `S`.
2421 /// In this example, when we descend to `w`, we will have built up the
2422 /// following two projected types:
2424 /// * base: `S`, projection: `(base.0).1`
2425 /// * base: `(i32, &'static str)`, projection: `base.1`
2427 /// The first will lead to the constraint `w: &'1 str` (for some
2428 /// inferred region `'1`). The second will lead to the constraint `w:
2430 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2431 pub struct UserTypeProjections {
2432 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2435 BraceStructTypeFoldableImpl! {
2436 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjections {
2441 impl<'tcx> UserTypeProjections {
2442 pub fn none() -> Self {
2443 UserTypeProjections { contents: vec![] }
2446 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2447 UserTypeProjections { contents: projs.collect() }
2450 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2451 self.contents.iter()
2454 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2455 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2458 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2459 self.contents.push((user_ty.clone(), span));
2465 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2467 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2471 pub fn index(self) -> Self {
2472 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2475 pub fn subslice(self, from: u32, to: u32) -> Self {
2476 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2479 pub fn deref(self) -> Self {
2480 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2483 pub fn leaf(self, field: Field) -> Self {
2484 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2487 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2488 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2492 /// Encodes the effect of a user-supplied type annotation on the
2493 /// subcomponents of a pattern. The effect is determined by applying the
2494 /// given list of proejctions to some underlying base type. Often,
2495 /// the projection element list `projs` is empty, in which case this
2496 /// directly encodes a type in `base`. But in the case of complex patterns with
2497 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2498 /// in which case the `projs` vector is used.
2502 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2504 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2505 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2506 /// determined by finding the type of the `.0` field from `T`.
2507 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2508 pub struct UserTypeProjection {
2509 pub base: UserTypeAnnotationIndex,
2510 pub projs: Vec<ProjectionKind>,
2513 impl Copy for ProjectionKind {}
2515 impl UserTypeProjection {
2516 pub(crate) fn index(mut self) -> Self {
2517 self.projs.push(ProjectionElem::Index(()));
2521 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2522 self.projs.push(ProjectionElem::Subslice { from, to });
2526 pub(crate) fn deref(mut self) -> Self {
2527 self.projs.push(ProjectionElem::Deref);
2531 pub(crate) fn leaf(mut self, field: Field) -> Self {
2532 self.projs.push(ProjectionElem::Field(field, ()));
2536 pub(crate) fn variant(
2538 adt_def: &'tcx AdtDef,
2539 variant_index: VariantIdx,
2542 self.projs.push(ProjectionElem::Downcast(
2543 Some(adt_def.variants[variant_index].ident.name),
2546 self.projs.push(ProjectionElem::Field(field, ()));
2551 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2553 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2554 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2555 use crate::mir::ProjectionElem::*;
2557 let base = self.base.fold_with(folder);
2558 let projs: Vec<_> = self
2561 .map(|elem| match elem {
2563 Field(f, ()) => Field(f.clone(), ()),
2564 Index(()) => Index(()),
2565 elem => elem.clone(),
2569 UserTypeProjection { base, projs }
2572 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2573 self.base.visit_with(visitor)
2574 // Note: there's nothing in `self.proj` to visit.
2579 pub struct Promoted {
2581 DEBUG_FORMAT = "promoted[{}]"
2585 impl<'tcx> Debug for Constant<'tcx> {
2586 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2587 write!(fmt, "{}", self)
2591 impl<'tcx> Display for Constant<'tcx> {
2592 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2593 write!(fmt, "const ")?;
2594 write!(fmt, "{}", self.literal)
2598 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2599 type Node = BasicBlock;
2602 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2603 fn num_nodes(&self) -> usize {
2604 self.basic_blocks.len()
2608 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2609 fn start_node(&self) -> Self::Node {
2614 impl<'tcx> graph::WithPredecessors for Body<'tcx> {
2618 ) -> <Self as GraphPredecessors<'_>>::Iter {
2619 self.predecessors_for(node).clone().into_iter()
2623 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2627 ) -> <Self as GraphSuccessors<'_>>::Iter {
2628 self.basic_blocks[node].terminator().successors().cloned()
2632 impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
2633 type Item = BasicBlock;
2634 type Iter = IntoIter<BasicBlock>;
2637 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2638 type Item = BasicBlock;
2639 type Iter = iter::Cloned<Successors<'b>>;
2642 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2643 pub struct Location {
2644 /// The block that the location is within.
2645 pub block: BasicBlock,
2647 /// The location is the position of the start of the statement; or, if
2648 /// `statement_index` equals the number of statements, then the start of the
2650 pub statement_index: usize,
2653 impl fmt::Debug for Location {
2654 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2655 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2660 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2662 /// Returns the location immediately after this one within the enclosing block.
2664 /// Note that if this location represents a terminator, then the
2665 /// resulting location would be out of bounds and invalid.
2666 pub fn successor_within_block(&self) -> Location {
2667 Location { block: self.block, statement_index: self.statement_index + 1 }
2670 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2671 pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
2672 // If we are in the same block as the other location and are an earlier statement
2673 // then we are a predecessor of `other`.
2674 if self.block == other.block && self.statement_index < other.statement_index {
2678 // If we're in another block, then we want to check that block is a predecessor of `other`.
2679 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).clone();
2680 let mut visited = FxHashSet::default();
2682 while let Some(block) = queue.pop() {
2683 // If we haven't visited this block before, then make sure we visit it's predecessors.
2684 if visited.insert(block) {
2685 queue.append(&mut body.predecessors_for(block).clone());
2690 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2691 // we found that block by looking at the predecessors of `other`).
2692 if self.block == block {
2700 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2701 if self.block == other.block {
2702 self.statement_index <= other.statement_index
2704 dominators.is_dominated_by(other.block, self.block)
2709 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2710 pub enum UnsafetyViolationKind {
2712 /// Permitted both in `const fn`s and regular `fn`s.
2714 ExternStatic(hir::HirId),
2715 BorrowPacked(hir::HirId),
2718 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2719 pub struct UnsafetyViolation {
2720 pub source_info: SourceInfo,
2721 pub description: InternedString,
2722 pub details: InternedString,
2723 pub kind: UnsafetyViolationKind,
2726 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2727 pub struct UnsafetyCheckResult {
2728 /// Violations that are propagated *upwards* from this function.
2729 pub violations: Lrc<[UnsafetyViolation]>,
2730 /// `unsafe` blocks in this function, along with whether they are used. This is
2731 /// used for the "unused_unsafe" lint.
2732 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2736 pub struct GeneratorSavedLocal {
2738 DEBUG_FORMAT = "_{}",
2742 /// The layout of generator state.
2743 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2744 pub struct GeneratorLayout<'tcx> {
2745 /// The type of every local stored inside the generator.
2746 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2748 /// Which of the above fields are in each variant. Note that one field may
2749 /// be stored in multiple variants.
2750 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2752 /// Which saved locals are storage-live at the same time. Locals that do not
2753 /// have conflicts with each other are allowed to overlap in the computed
2755 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2757 /// The names and scopes of all the stored generator locals.
2759 /// N.B., this is *strictly* a temporary hack for codegen
2760 /// debuginfo generation, and will be removed at some point.
2761 /// Do **NOT** use it for anything else, local information should not be
2762 /// in the MIR, please rely on local crate HIR or other side-channels.
2764 // FIXME(tmandry): see above.
2765 pub __local_debuginfo_codegen_only_do_not_use: IndexVec<GeneratorSavedLocal, LocalDecl<'tcx>>,
2768 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2769 pub struct BorrowCheckResult<'tcx> {
2770 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2771 pub used_mut_upvars: SmallVec<[Field; 8]>,
2774 /// After we borrow check a closure, we are left with various
2775 /// requirements that we have inferred between the free regions that
2776 /// appear in the closure's signature or on its field types. These
2777 /// requirements are then verified and proved by the closure's
2778 /// creating function. This struct encodes those requirements.
2780 /// The requirements are listed as being between various
2781 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2782 /// vids refer to the free regions that appear in the closure (or
2783 /// generator's) type, in order of appearance. (This numbering is
2784 /// actually defined by the `UniversalRegions` struct in the NLL
2785 /// region checker. See for example
2786 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2787 /// regions in the closure's type "as if" they were erased, so their
2788 /// precise identity is not important, only their position.
2790 /// Example: If type check produces a closure with the closure substs:
2793 /// ClosureSubsts = [
2794 /// i8, // the "closure kind"
2795 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2796 /// &'a String, // some upvar
2800 /// here, there is one unique free region (`'a`) but it appears
2801 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2804 /// ClosureSubsts = [
2805 /// i8, // the "closure kind"
2806 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2807 /// &'2 String, // some upvar
2811 /// Now the code might impose a requirement like `'1: '2`. When an
2812 /// instance of the closure is created, the corresponding free regions
2813 /// can be extracted from its type and constrained to have the given
2814 /// outlives relationship.
2816 /// In some cases, we have to record outlives requirements between
2817 /// types and regions as well. In that case, if those types include
2818 /// any regions, those regions are recorded as `ReClosureBound`
2819 /// instances assigned one of these same indices. Those regions will
2820 /// be substituted away by the creator. We use `ReClosureBound` in
2821 /// that case because the regions must be allocated in the global
2822 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2823 /// internally within the rest of the NLL code).
2824 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2825 pub struct ClosureRegionRequirements<'tcx> {
2826 /// The number of external regions defined on the closure. In our
2827 /// example above, it would be 3 -- one for `'static`, then `'1`
2828 /// and `'2`. This is just used for a sanity check later on, to
2829 /// make sure that the number of regions we see at the callsite
2831 pub num_external_vids: usize,
2833 /// Requirements between the various free regions defined in
2835 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2838 /// Indicates an outlives-constraint between a type or between two
2839 /// free regions declared on the closure.
2840 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2841 pub struct ClosureOutlivesRequirement<'tcx> {
2842 // This region or type ...
2843 pub subject: ClosureOutlivesSubject<'tcx>,
2845 // ... must outlive this one.
2846 pub outlived_free_region: ty::RegionVid,
2848 // If not, report an error here ...
2849 pub blame_span: Span,
2851 // ... due to this reason.
2852 pub category: ConstraintCategory,
2855 /// Outlives-constraints can be categorized to determine whether and why they
2856 /// are interesting (for error reporting). Order of variants indicates sort
2857 /// order of the category, thereby influencing diagnostic output.
2859 /// See also [rustc_mir::borrow_check::nll::constraints].
2873 pub enum ConstraintCategory {
2881 /// A constraint that came from checking the body of a closure.
2883 /// We try to get the category that the closure used when reporting this.
2891 /// A "boring" constraint (caused by the given location) is one that
2892 /// the user probably doesn't want to see described in diagnostics,
2893 /// because it is kind of an artifact of the type system setup.
2894 /// Example: `x = Foo { field: y }` technically creates
2895 /// intermediate regions representing the "type of `Foo { field: y
2896 /// }`", and data flows from `y` into those variables, but they
2897 /// are not very interesting. The assignment into `x` on the other
2900 // Boring and applicable everywhere.
2903 /// A constraint that doesn't correspond to anything the user sees.
2907 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2908 /// that must outlive some region.
2909 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2910 pub enum ClosureOutlivesSubject<'tcx> {
2911 /// Subject is a type, typically a type parameter, but could also
2912 /// be a projection. Indicates a requirement like `T: 'a` being
2913 /// passed to the caller, where the type here is `T`.
2915 /// The type here is guaranteed not to contain any free regions at
2919 /// Subject is a free region from the closure. Indicates a requirement
2920 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2921 Region(ty::RegionVid),
2925 * `TypeFoldable` implementations for MIR types
2928 CloneTypeFoldableAndLiftImpls! {
2938 SourceScopeLocalData,
2939 UserTypeAnnotationIndex,
2942 BraceStructTypeFoldableImpl! {
2943 impl<'tcx> TypeFoldable<'tcx> for Body<'tcx> {
2947 source_scope_local_data,
2952 user_type_annotations,
2954 __upvar_debuginfo_codegen_only_do_not_use,
2956 control_flow_destroyed,
2962 BraceStructTypeFoldableImpl! {
2963 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
2967 __local_debuginfo_codegen_only_do_not_use,
2971 BraceStructTypeFoldableImpl! {
2972 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
2985 BraceStructTypeFoldableImpl! {
2986 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
2993 BraceStructTypeFoldableImpl! {
2994 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
2999 EnumTypeFoldableImpl! {
3000 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
3001 (StatementKind::Assign)(a),
3002 (StatementKind::FakeRead)(cause, place),
3003 (StatementKind::SetDiscriminant) { place, variant_index },
3004 (StatementKind::StorageLive)(a),
3005 (StatementKind::StorageDead)(a),
3006 (StatementKind::InlineAsm)(a),
3007 (StatementKind::Retag)(kind, place),
3008 (StatementKind::AscribeUserType)(a, v),
3009 (StatementKind::Nop),
3013 BraceStructTypeFoldableImpl! {
3014 impl<'tcx> TypeFoldable<'tcx> for InlineAsm<'tcx> {
3021 EnumTypeFoldableImpl! {
3022 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
3023 (ClearCrossCrate::Clear),
3024 (ClearCrossCrate::Set)(a),
3025 } where T: TypeFoldable<'tcx>
3028 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
3029 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3030 use crate::mir::TerminatorKind::*;
3032 let kind = match self.kind {
3033 Goto { target } => Goto { target },
3034 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
3035 discr: discr.fold_with(folder),
3036 switch_ty: switch_ty.fold_with(folder),
3037 values: values.clone(),
3038 targets: targets.clone(),
3040 Drop { ref location, target, unwind } => {
3041 Drop { location: location.fold_with(folder), target, unwind }
3043 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
3044 location: location.fold_with(folder),
3045 value: value.fold_with(folder),
3049 Yield { ref value, resume, drop } => {
3050 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
3052 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
3054 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
3057 func: func.fold_with(folder),
3058 args: args.fold_with(folder),
3064 Assert { ref cond, expected, ref msg, target, cleanup } => {
3066 let msg = match msg {
3067 BoundsCheck { ref len, ref index } =>
3069 len: len.fold_with(folder),
3070 index: index.fold_with(folder),
3072 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
3073 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
3076 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
3078 GeneratorDrop => GeneratorDrop,
3082 Unreachable => Unreachable,
3083 FalseEdges { real_target, imaginary_target } => {
3084 FalseEdges { real_target, imaginary_target }
3086 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
3088 Terminator { source_info: self.source_info, kind }
3091 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3092 use crate::mir::TerminatorKind::*;
3095 SwitchInt { ref discr, switch_ty, .. } => {
3096 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
3098 Drop { ref location, .. } => location.visit_with(visitor),
3099 DropAndReplace { ref location, ref value, .. } => {
3100 location.visit_with(visitor) || value.visit_with(visitor)
3102 Yield { ref value, .. } => value.visit_with(visitor),
3103 Call { ref func, ref args, ref destination, .. } => {
3104 let dest = if let Some((ref loc, _)) = *destination {
3105 loc.visit_with(visitor)
3109 dest || func.visit_with(visitor) || args.visit_with(visitor)
3111 Assert { ref cond, ref msg, .. } => {
3112 if cond.visit_with(visitor) {
3115 BoundsCheck { ref len, ref index } =>
3116 len.visit_with(visitor) || index.visit_with(visitor),
3117 Panic { .. } | Overflow(_) | OverflowNeg |
3118 DivisionByZero | RemainderByZero |
3119 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
3133 | FalseUnwind { .. } => false,
3138 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3139 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3141 base: self.base.fold_with(folder),
3142 projection: self.projection.fold_with(folder),
3146 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3147 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3151 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3152 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3154 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3155 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3159 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3161 PlaceBase::Local(local) => local.visit_with(visitor),
3162 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3167 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3168 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3170 ty: self.ty.fold_with(folder),
3171 kind: self.kind.fold_with(folder),
3172 def_id: self.def_id,
3176 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3177 let Static { ty, kind, def_id: _ } = self;
3179 ty.visit_with(visitor) || kind.visit_with(visitor)
3183 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3184 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3186 StaticKind::Promoted(promoted, substs) =>
3187 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3188 StaticKind::Static => StaticKind::Static
3192 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3194 StaticKind::Promoted(promoted, substs) =>
3195 promoted.visit_with(visitor) || substs.visit_with(visitor),
3196 StaticKind::Static => { false }
3201 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3202 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3203 use crate::mir::Rvalue::*;
3205 Use(ref op) => Use(op.fold_with(folder)),
3206 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3207 Ref(region, bk, ref place) => {
3208 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3210 Len(ref place) => Len(place.fold_with(folder)),
3211 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3212 BinaryOp(op, ref rhs, ref lhs) => {
3213 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3215 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3216 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3218 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3219 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3220 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3221 Aggregate(ref kind, ref fields) => {
3222 let kind = box match **kind {
3223 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3224 AggregateKind::Tuple => AggregateKind::Tuple,
3225 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3228 substs.fold_with(folder),
3229 user_ty.fold_with(folder),
3232 AggregateKind::Closure(id, substs) => {
3233 AggregateKind::Closure(id, substs.fold_with(folder))
3235 AggregateKind::Generator(id, substs, movablity) => {
3236 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3239 Aggregate(kind, fields.fold_with(folder))
3244 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3245 use crate::mir::Rvalue::*;
3247 Use(ref op) => op.visit_with(visitor),
3248 Repeat(ref op, _) => op.visit_with(visitor),
3249 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3250 Len(ref place) => place.visit_with(visitor),
3251 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3252 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3253 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3255 UnaryOp(_, ref val) => val.visit_with(visitor),
3256 Discriminant(ref place) => place.visit_with(visitor),
3257 NullaryOp(_, ty) => ty.visit_with(visitor),
3258 Aggregate(ref kind, ref fields) => {
3260 AggregateKind::Array(ty) => ty.visit_with(visitor),
3261 AggregateKind::Tuple => false,
3262 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3263 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3265 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3266 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3267 }) || fields.visit_with(visitor)
3273 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3274 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3276 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3277 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3278 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3282 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3284 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3285 Operand::Constant(ref c) => c.visit_with(visitor),
3290 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3291 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3292 use crate::mir::ProjectionElem::*;
3296 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3297 Index(v) => Index(v.fold_with(folder)),
3298 elem => elem.clone(),
3302 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3303 use crate::mir::ProjectionElem::*;
3306 Field(_, ty) => ty.visit_with(visitor),
3307 Index(v) => v.visit_with(visitor),
3313 impl<'tcx> TypeFoldable<'tcx> for Field {
3314 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3317 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3322 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3323 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3326 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3331 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3332 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3335 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3340 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3341 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3343 span: self.span.clone(),
3344 user_ty: self.user_ty.fold_with(folder),
3345 literal: self.literal.fold_with(folder),
3348 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3349 self.literal.visit_with(visitor)