1 // ignore-tidy-filelength
3 //! MIR datatypes and passes. See the [rustc guide] for more info.
5 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
7 use crate::hir::def::{CtorKind, Namespace};
8 use crate::hir::def_id::DefId;
9 use crate::hir::{self, GeneratorKind};
10 use crate::mir::interpret::{GlobalAlloc, PanicInfo, Scalar};
11 use crate::mir::visit::MirVisitable;
12 use crate::ty::adjustment::PointerCast;
13 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
14 use crate::ty::layout::VariantIdx;
15 use crate::ty::print::{FmtPrinter, Printer};
16 use crate::ty::subst::{Subst, SubstsRef};
18 self, AdtDef, CanonicalUserTypeAnnotations, List, Region, Ty, TyCtxt, UserTypeAnnotationIndex,
21 use polonius_engine::Atom;
22 use rustc_index::bit_set::BitMatrix;
23 use rustc_data_structures::fx::FxHashSet;
24 use rustc_data_structures::graph::dominators::{dominators, Dominators};
25 use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
26 use rustc_index::vec::{Idx, IndexVec};
27 use rustc_data_structures::sync::Lrc;
28 use rustc_data_structures::sync::MappedReadGuard;
29 use rustc_macros::HashStable;
30 use rustc_serialize::{Encodable, Decodable};
31 use smallvec::SmallVec;
33 use std::fmt::{self, Debug, Display, Formatter, Write};
34 use std::ops::{Index, IndexMut};
36 use std::vec::IntoIter;
37 use std::{iter, mem, option, u32};
38 use syntax::ast::Name;
39 use syntax::symbol::Symbol;
40 use syntax_pos::{Span, DUMMY_SP};
42 pub use crate::mir::interpret::AssertMessage;
52 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
54 pub trait HasLocalDecls<'tcx> {
55 fn local_decls(&self) -> &LocalDecls<'tcx>;
58 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
59 fn local_decls(&self) -> &LocalDecls<'tcx> {
64 impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
65 fn local_decls(&self) -> &LocalDecls<'tcx> {
70 /// The various "big phases" that MIR goes through.
72 /// Warning: ordering of variants is significant.
73 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, HashStable,
74 Debug, PartialEq, Eq, PartialOrd, Ord)]
83 /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
84 pub fn phase_index(&self) -> usize {
89 /// The lowered representation of a single function.
90 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, HashStable, TypeFoldable)]
91 pub struct Body<'tcx> {
92 /// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
93 /// that indexes into this vector.
94 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
96 /// Records how far through the "desugaring and optimization" process this particular
97 /// MIR has traversed. This is particularly useful when inlining, since in that context
98 /// we instantiate the promoted constants and add them to our promoted vector -- but those
99 /// promoted items have already been optimized, whereas ours have not. This field allows
100 /// us to see the difference and forego optimization on the inlined promoted items.
103 /// A list of source scopes; these are referenced by statements
104 /// and used for debuginfo. Indexed by a `SourceScope`.
105 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
107 /// 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 /// If this is a generator then record the type of source expression that caused this generator
122 pub generator_kind: Option<GeneratorKind>,
124 /// Declarations of locals.
126 /// The first local is the return value pointer, followed by `arg_count`
127 /// locals for the function arguments, followed by any user-declared
128 /// variables and temporaries.
129 pub local_decls: LocalDecls<'tcx>,
131 /// User type annotations.
132 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
134 /// The number of arguments this function takes.
136 /// Starting at local 1, `arg_count` locals will be provided by the caller
137 /// and can be assumed to be initialized.
139 /// If this MIR was built for a constant, this will be 0.
140 pub arg_count: usize,
142 /// Mark an argument local (which must be a tuple) as getting passed as
143 /// its individual components at the LLVM level.
145 /// This is used for the "rust-call" ABI.
146 pub spread_arg: Option<Local>,
148 /// Debug information pertaining to user variables, including captures.
149 pub var_debug_info: Vec<VarDebugInfo<'tcx>>,
151 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
152 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
153 /// this conversion from happening and use short circuiting, we will cause the following code
154 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
156 /// List of places where control flow was destroyed. Used for error reporting.
157 pub control_flow_destroyed: Vec<(Span, String)>,
159 /// A span representing this MIR, for error reporting.
162 /// A cache for various calculations.
166 impl<'tcx> Body<'tcx> {
168 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
169 source_scopes: IndexVec<SourceScope, SourceScopeData>,
170 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
171 local_decls: LocalDecls<'tcx>,
172 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
174 var_debug_info: Vec<VarDebugInfo<'tcx>>,
176 control_flow_destroyed: Vec<(Span, String)>,
177 generator_kind : Option<GeneratorKind>,
179 // We need `arg_count` locals, and one for the return place.
181 local_decls.len() >= arg_count + 1,
182 "expected at least {} locals, got {}",
188 phase: MirPhase::Build,
191 source_scope_local_data,
193 generator_drop: None,
194 generator_layout: None,
197 user_type_annotations,
202 cache: cache::Cache::new(),
203 control_flow_destroyed,
208 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
213 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
214 self.cache.invalidate();
215 &mut self.basic_blocks
219 pub fn basic_blocks_and_local_decls_mut(
221 ) -> (&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>, &mut LocalDecls<'tcx>) {
222 self.cache.invalidate();
223 (&mut self.basic_blocks, &mut self.local_decls)
227 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
228 self.cache.predecessors(self)
232 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
233 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
237 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
238 let if_zero_locations = if loc.statement_index == 0 {
239 let predecessor_blocks = self.predecessors_for(loc.block);
240 let num_predecessor_blocks = predecessor_blocks.len();
242 (0..num_predecessor_blocks)
243 .map(move |i| predecessor_blocks[i])
244 .map(move |bb| self.terminator_loc(bb)),
250 let if_not_zero_locations = if loc.statement_index == 0 {
253 Some(Location { block: loc.block, statement_index: loc.statement_index - 1 })
256 if_zero_locations.into_iter().flatten().chain(if_not_zero_locations)
260 pub fn dominators(&self) -> Dominators<BasicBlock> {
264 /// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
266 pub fn is_cfg_cyclic(&self) -> bool {
267 graph::is_cyclic(self)
271 pub fn local_kind(&self, local: Local) -> LocalKind {
272 let index = local.as_usize();
275 self.local_decls[local].mutability == Mutability::Mut,
276 "return place should be mutable"
279 LocalKind::ReturnPointer
280 } else if index < self.arg_count + 1 {
282 } else if self.local_decls[local].is_user_variable() {
289 /// Returns an iterator over all temporaries.
291 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
292 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
293 let local = Local::new(index);
294 if self.local_decls[local].is_user_variable() {
302 /// Returns an iterator over all user-declared locals.
304 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
305 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
306 let local = Local::new(index);
307 if self.local_decls[local].is_user_variable() {
315 /// Returns an iterator over all user-declared mutable locals.
317 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
318 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
319 let local = Local::new(index);
320 let decl = &self.local_decls[local];
321 if decl.is_user_variable() && decl.mutability == Mutability::Mut {
329 /// Returns an iterator over all user-declared mutable arguments and locals.
331 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
332 (1..self.local_decls.len()).filter_map(move |index| {
333 let local = Local::new(index);
334 let decl = &self.local_decls[local];
335 if (decl.is_user_variable() || index < self.arg_count + 1)
336 && decl.mutability == Mutability::Mut
345 /// Returns an iterator over all function arguments.
347 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
348 let arg_count = self.arg_count;
349 (1..=arg_count).map(Local::new)
352 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
353 /// locals that are neither arguments nor the return place).
355 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
356 let arg_count = self.arg_count;
357 let local_count = self.local_decls.len();
358 (arg_count + 1..local_count).map(Local::new)
361 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
362 /// invalidating statement indices in `Location`s.
363 pub fn make_statement_nop(&mut self, location: Location) {
364 let block = &mut self[location.block];
365 debug_assert!(location.statement_index < block.statements.len());
366 block.statements[location.statement_index].make_nop()
369 /// Returns the source info associated with `location`.
370 pub fn source_info(&self, location: Location) -> &SourceInfo {
371 let block = &self[location.block];
372 let stmts = &block.statements;
373 let idx = location.statement_index;
374 if idx < stmts.len() {
375 &stmts[idx].source_info
377 assert_eq!(idx, stmts.len());
378 &block.terminator().source_info
382 /// Checks if `sub` is a sub scope of `sup`
383 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
385 match self.source_scopes[sub].parent_scope {
386 None => return false,
393 /// Returns the return type; it always return first element from `local_decls` array.
394 pub fn return_ty(&self) -> Ty<'tcx> {
395 self.local_decls[RETURN_PLACE].ty
398 /// Gets the location of the terminator for the given block.
399 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
400 Location { block: bb, statement_index: self[bb].statements.len() }
404 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
407 /// Unsafe because of a PushUnsafeBlock
409 /// Unsafe because of an unsafe fn
411 /// Unsafe because of an `unsafe` block
412 ExplicitUnsafe(hir::HirId),
415 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
416 type Output = BasicBlockData<'tcx>;
419 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
420 &self.basic_blocks()[index]
424 impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
426 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
427 &mut self.basic_blocks_mut()[index]
431 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
432 pub enum ClearCrossCrate<T> {
437 impl<T> ClearCrossCrate<T> {
438 pub fn assert_crate_local(self) -> T {
440 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
441 ClearCrossCrate::Set(v) => v,
446 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
447 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
449 /// Grouped information about the source code origin of a MIR entity.
450 /// Intended to be inspected by diagnostics and debuginfo.
451 /// Most passes can work with it as a whole, within a single function.
452 // The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
453 // `Hash`. Please ping @bjorn3 if removing them.
454 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
455 pub struct SourceInfo {
456 /// The source span for the AST pertaining to this MIR entity.
459 /// The source scope, keeping track of which bindings can be
460 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
461 pub scope: SourceScope,
464 ///////////////////////////////////////////////////////////////////////////
465 // Mutability and borrow kinds
467 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
468 pub enum Mutability {
473 impl From<Mutability> for hir::Mutability {
474 fn from(m: Mutability) -> Self {
476 Mutability::Mut => hir::Mutability::Mutable,
477 Mutability::Not => hir::Mutability::Immutable,
483 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
485 pub enum BorrowKind {
486 /// Data must be immutable and is aliasable.
489 /// The immediately borrowed place must be immutable, but projections from
490 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
491 /// conflict with a mutable borrow of `a.b.c`.
493 /// This is used when lowering matches: when matching on a place we want to
494 /// ensure that place have the same value from the start of the match until
495 /// an arm is selected. This prevents this code from compiling:
497 /// let mut x = &Some(0);
500 /// Some(_) if { x = &None; false } => (),
504 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
505 /// should not prevent `if let None = x { ... }`, for example, because the
506 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
507 /// We can also report errors with this kind of borrow differently.
510 /// Data must be immutable but not aliasable. This kind of borrow
511 /// cannot currently be expressed by the user and is used only in
512 /// implicit closure bindings. It is needed when the closure is
513 /// borrowing or mutating a mutable referent, e.g.:
515 /// let x: &mut isize = ...;
516 /// let y = || *x += 5;
518 /// If we were to try to translate this closure into a more explicit
519 /// form, we'd encounter an error with the code as written:
521 /// struct Env { x: & &mut isize }
522 /// let x: &mut isize = ...;
523 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
524 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
526 /// This is then illegal because you cannot mutate an `&mut` found
527 /// in an aliasable location. To solve, you'd have to translate with
528 /// an `&mut` borrow:
530 /// struct Env { x: & &mut isize }
531 /// let x: &mut isize = ...;
532 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
533 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
535 /// Now the assignment to `**env.x` is legal, but creating a
536 /// mutable pointer to `x` is not because `x` is not mutable. We
537 /// could fix this by declaring `x` as `let mut x`. This is ok in
538 /// user code, if awkward, but extra weird for closures, since the
539 /// borrow is hidden.
541 /// So we introduce a "unique imm" borrow -- the referent is
542 /// immutable, but not aliasable. This solves the problem. For
543 /// simplicity, we don't give users the way to express this
544 /// borrow, it's just used when translating closures.
547 /// Data is mutable and not aliasable.
549 /// `true` if this borrow arose from method-call auto-ref
550 /// (i.e., `adjustment::Adjust::Borrow`).
551 allow_two_phase_borrow: bool,
556 pub fn allows_two_phase_borrow(&self) -> bool {
558 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
559 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
564 ///////////////////////////////////////////////////////////////////////////
565 // Variables and temps
567 rustc_index::newtype_index! {
570 DEBUG_FORMAT = "_{}",
571 const RETURN_PLACE = 0,
575 impl Atom for Local {
576 fn index(self) -> usize {
581 /// Classifies locals into categories. See `Body::local_kind`.
582 #[derive(PartialEq, Eq, Debug, HashStable)]
584 /// User-declared variable binding.
586 /// Compiler-introduced temporary.
588 /// Function argument.
590 /// Location of function's return value.
594 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
595 pub struct VarBindingForm<'tcx> {
596 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
597 pub binding_mode: ty::BindingMode,
598 /// If an explicit type was provided for this variable binding,
599 /// this holds the source Span of that type.
601 /// NOTE: if you want to change this to a `HirId`, be wary that
602 /// doing so breaks incremental compilation (as of this writing),
603 /// while a `Span` does not cause our tests to fail.
604 pub opt_ty_info: Option<Span>,
605 /// Place of the RHS of the =, or the subject of the `match` where this
606 /// variable is initialized. None in the case of `let PATTERN;`.
607 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
608 /// (a) the right-hand side isn't evaluated as a place expression.
609 /// (b) it gives a way to separate this case from the remaining cases
611 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
612 /// The span of the pattern in which this variable was bound.
616 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
617 pub enum BindingForm<'tcx> {
618 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
619 Var(VarBindingForm<'tcx>),
620 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
621 ImplicitSelf(ImplicitSelfKind),
622 /// Reference used in a guard expression to ensure immutability.
626 /// Represents what type of implicit self a function has, if any.
627 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
628 pub enum ImplicitSelfKind {
629 /// Represents a `fn x(self);`.
631 /// Represents a `fn x(mut self);`.
633 /// Represents a `fn x(&self);`.
635 /// Represents a `fn x(&mut self);`.
637 /// Represents when a function does not have a self argument or
638 /// when a function has a `self: X` argument.
642 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
644 mod binding_form_impl {
645 use crate::ich::StableHashingContext;
646 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
648 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
649 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
650 use super::BindingForm::*;
651 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
654 Var(binding) => binding.hash_stable(hcx, hasher),
655 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
662 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
663 /// created during evaluation of expressions in a block tail
664 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
666 /// It is used to improve diagnostics when such temporaries are
667 /// involved in borrow_check errors, e.g., explanations of where the
668 /// temporaries come from, when their destructors are run, and/or how
669 /// one might revise the code to satisfy the borrow checker's rules.
670 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
671 pub struct BlockTailInfo {
672 /// If `true`, then the value resulting from evaluating this tail
673 /// expression is ignored by the block's expression context.
675 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
676 /// but not e.g., `let _x = { ...; tail };`
677 pub tail_result_is_ignored: bool,
682 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
683 /// argument, or the return place.
684 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
685 pub struct LocalDecl<'tcx> {
686 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
688 /// Temporaries and the return place are always mutable.
689 pub mutability: Mutability,
691 // FIXME(matthewjasper) Don't store in this in `Body`
692 pub local_info: LocalInfo<'tcx>,
694 /// `true` if this is an internal local.
696 /// These locals are not based on types in the source code and are only used
697 /// for a few desugarings at the moment.
699 /// The generator transformation will sanity check the locals which are live
700 /// across a suspension point against the type components of the generator
701 /// which type checking knows are live across a suspension point. We need to
702 /// flag drop flags to avoid triggering this check as they are introduced
705 /// Unsafety checking will also ignore dereferences of these locals,
706 /// so they can be used for raw pointers only used in a desugaring.
708 /// This should be sound because the drop flags are fully algebraic, and
709 /// therefore don't affect the OIBIT or outlives properties of the
713 /// If this local is a temporary and `is_block_tail` is `Some`,
714 /// then it is a temporary created for evaluation of some
715 /// subexpression of some block's tail expression (with no
716 /// intervening statement context).
717 // FIXME(matthewjasper) Don't store in this in `Body`
718 pub is_block_tail: Option<BlockTailInfo>,
720 /// The type of this local.
723 /// If the user manually ascribed a type to this variable,
724 /// e.g., via `let x: T`, then we carry that type here. The MIR
725 /// borrow checker needs this information since it can affect
726 /// region inference.
727 // FIXME(matthewjasper) Don't store in this in `Body`
728 pub user_ty: UserTypeProjections,
730 /// The *syntactic* (i.e., not visibility) source scope the local is defined
731 /// in. If the local was defined in a let-statement, this
732 /// is *within* the let-statement, rather than outside
735 /// This is needed because the visibility source scope of locals within
736 /// a let-statement is weird.
738 /// The reason is that we want the local to be *within* the let-statement
739 /// for lint purposes, but we want the local to be *after* the let-statement
740 /// for names-in-scope purposes.
742 /// That's it, if we have a let-statement like the one in this
746 /// fn foo(x: &str) {
747 /// #[allow(unused_mut)]
748 /// let mut x: u32 = { // <- one unused mut
749 /// let mut y: u32 = x.parse().unwrap();
756 /// Then, from a lint point of view, the declaration of `x: u32`
757 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
758 /// lint scopes are the same as the AST/HIR nesting.
760 /// However, from a name lookup point of view, the scopes look more like
761 /// as if the let-statements were `match` expressions:
764 /// fn foo(x: &str) {
766 /// match x.parse().unwrap() {
775 /// We care about the name-lookup scopes for debuginfo - if the
776 /// debuginfo instruction pointer is at the call to `x.parse()`, we
777 /// want `x` to refer to `x: &str`, but if it is at the call to
778 /// `drop(x)`, we want it to refer to `x: u32`.
780 /// To allow both uses to work, we need to have more than a single scope
781 /// for a local. We have the `source_info.scope` represent the "syntactic"
782 /// lint scope (with a variable being under its let block) while the
783 /// `var_debug_info.source_info.scope` represents the "local variable"
784 /// scope (where the "rest" of a block is under all prior let-statements).
786 /// The end result looks like this:
790 /// │{ argument x: &str }
792 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
793 /// │ │ // in practice because I'm lazy.
795 /// │ │← x.source_info.scope
796 /// │ │← `x.parse().unwrap()`
798 /// │ │ │← y.source_info.scope
800 /// │ │ │{ let y: u32 }
802 /// │ │ │← y.var_debug_info.source_info.scope
805 /// │ │{ let x: u32 }
806 /// │ │← x.var_debug_info.source_info.scope
807 /// │ │← `drop(x)` // This accesses `x: u32`.
809 pub source_info: SourceInfo,
812 /// Extra information about a local that's used for diagnostics.
813 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
814 pub enum LocalInfo<'tcx> {
815 /// A user-defined local variable or function parameter
817 /// The `BindingForm` is solely used for local diagnostics when generating
818 /// warnings/errors when compiling the current crate, and therefore it need
819 /// not be visible across crates.
820 User(ClearCrossCrate<BindingForm<'tcx>>),
821 /// A temporary created that references the static with the given `DefId`.
822 StaticRef { def_id: DefId, is_thread_local: bool },
823 /// Any other temporary, the return place, or an anonymous function parameter.
827 impl<'tcx> LocalDecl<'tcx> {
828 /// Returns `true` only if local is a binding that can itself be
829 /// made mutable via the addition of the `mut` keyword, namely
830 /// something like the occurrences of `x` in:
831 /// - `fn foo(x: Type) { ... }`,
833 /// - or `match ... { C(x) => ... }`
834 pub fn can_be_made_mutable(&self) -> bool {
835 match self.local_info {
836 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
837 binding_mode: ty::BindingMode::BindByValue(_),
844 ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)),
851 /// Returns `true` if local is definitely not a `ref ident` or
852 /// `ref mut ident` binding. (Such bindings cannot be made into
853 /// mutable bindings, but the inverse does not necessarily hold).
854 pub fn is_nonref_binding(&self) -> bool {
855 match self.local_info {
856 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
857 binding_mode: ty::BindingMode::BindByValue(_),
863 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
869 /// Returns `true` if this variable is a named variable or function
870 /// parameter declared by the user.
872 pub fn is_user_variable(&self) -> bool {
873 match self.local_info {
874 LocalInfo::User(_) => true,
879 /// Returns `true` if this is a reference to a variable bound in a `match`
880 /// expression that is used to access said variable for the guard of the
882 pub fn is_ref_for_guard(&self) -> bool {
883 match self.local_info {
884 LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
889 /// Returns `Some` if this is a reference to a static item that is used to
890 /// access that static
891 pub fn is_ref_to_static(&self) -> bool {
892 match self.local_info {
893 LocalInfo::StaticRef { .. } => true,
898 /// Returns `Some` if this is a reference to a static item that is used to
899 /// access that static
900 pub fn is_ref_to_thread_local(&self) -> bool {
901 match self.local_info {
902 LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
907 /// Returns `true` is the local is from a compiler desugaring, e.g.,
908 /// `__next` from a `for` loop.
910 pub fn from_compiler_desugaring(&self) -> bool {
911 self.source_info.span.desugaring_kind().is_some()
914 /// Creates a new `LocalDecl` for a temporary.
916 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
917 Self::new_local(ty, Mutability::Mut, false, span)
920 /// Converts `self` into same `LocalDecl` except tagged as immutable.
922 pub fn immutable(mut self) -> Self {
923 self.mutability = Mutability::Not;
927 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
929 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
930 assert!(self.is_block_tail.is_none());
931 self.is_block_tail = Some(info);
935 /// Creates a new `LocalDecl` for a internal temporary.
937 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
938 Self::new_local(ty, Mutability::Mut, true, span)
942 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
946 user_ty: UserTypeProjections::none(),
947 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
949 local_info: LocalInfo::Other,
954 /// Builds a `LocalDecl` for the return place.
956 /// This must be inserted into the `local_decls` list as the first local.
958 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
960 mutability: Mutability::Mut,
962 user_ty: UserTypeProjections::none(),
963 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
966 local_info: LocalInfo::Other,
971 /// Debug information pertaining to a user variable.
972 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
973 pub struct VarDebugInfo<'tcx> {
976 /// Source info of the user variable, including the scope
977 /// within which the variable is visible (to debuginfo)
978 /// (see `LocalDecl`'s `source_info` field for more details).
979 pub source_info: SourceInfo,
981 /// Where the data for this user variable is to be found.
982 /// NOTE(eddyb) There's an unenforced invariant that this `Place` is
983 /// based on a `Local`, not a `Static`, and contains no indexing.
984 pub place: Place<'tcx>,
987 ///////////////////////////////////////////////////////////////////////////
990 rustc_index::newtype_index! {
991 pub struct BasicBlock {
993 DEBUG_FORMAT = "bb{}",
994 const START_BLOCK = 0,
999 pub fn start_location(self) -> Location {
1000 Location { block: self, statement_index: 0 }
1004 ///////////////////////////////////////////////////////////////////////////
1005 // BasicBlockData and Terminator
1007 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1008 pub struct BasicBlockData<'tcx> {
1009 /// List of statements in this block.
1010 pub statements: Vec<Statement<'tcx>>,
1012 /// Terminator for this block.
1014 /// N.B., this should generally ONLY be `None` during construction.
1015 /// Therefore, you should generally access it via the
1016 /// `terminator()` or `terminator_mut()` methods. The only
1017 /// exception is that certain passes, such as `simplify_cfg`, swap
1018 /// out the terminator temporarily with `None` while they continue
1019 /// to recurse over the set of basic blocks.
1020 pub terminator: Option<Terminator<'tcx>>,
1022 /// If true, this block lies on an unwind path. This is used
1023 /// during codegen where distinct kinds of basic blocks may be
1024 /// generated (particularly for MSVC cleanup). Unwind blocks must
1025 /// only branch to other unwind blocks.
1026 pub is_cleanup: bool,
1029 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1030 pub struct Terminator<'tcx> {
1031 pub source_info: SourceInfo,
1032 pub kind: TerminatorKind<'tcx>,
1035 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
1036 pub enum TerminatorKind<'tcx> {
1037 /// Block should have one successor in the graph; we jump there.
1038 Goto { target: BasicBlock },
1040 /// Operand evaluates to an integer; jump depending on its value
1041 /// to one of the targets, and otherwise fallback to `otherwise`.
1043 /// The discriminant value being tested.
1044 discr: Operand<'tcx>,
1046 /// The type of value being tested.
1047 switch_ty: Ty<'tcx>,
1049 /// Possible values. The locations to branch to in each case
1050 /// are found in the corresponding indices from the `targets` vector.
1051 values: Cow<'tcx, [u128]>,
1053 /// Possible branch sites. The last element of this vector is used
1054 /// for the otherwise branch, so targets.len() == values.len() + 1
1057 // This invariant is quite non-obvious and also could be improved.
1058 // One way to make this invariant is to have something like this instead:
1060 // branches: Vec<(ConstInt, BasicBlock)>,
1061 // otherwise: Option<BasicBlock> // exhaustive if None
1063 // However we’ve decided to keep this as-is until we figure a case
1064 // where some other approach seems to be strictly better than other.
1065 targets: Vec<BasicBlock>,
1068 /// Indicates that the landing pad is finished and unwinding should
1069 /// continue. Emitted by `build::scope::diverge_cleanup`.
1072 /// Indicates that the landing pad is finished and that the process
1073 /// should abort. Used to prevent unwinding for foreign items.
1076 /// Indicates a normal return. The return place should have
1077 /// been filled in by now. This should occur at most once.
1080 /// Indicates a terminator that can never be reached.
1083 /// Drop the `Place`.
1084 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1086 /// Drop the `Place` and assign the new value over it. This ensures
1087 /// that the assignment to `P` occurs *even if* the destructor for
1088 /// place unwinds. Its semantics are best explained by the
1093 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1101 /// Drop(P, goto BB1, unwind BB2)
1104 /// // P is now uninitialized
1108 /// // P is now uninitialized -- its dtor panicked
1113 location: Place<'tcx>,
1114 value: Operand<'tcx>,
1116 unwind: Option<BasicBlock>,
1119 /// Block ends with a call of a converging function.
1121 /// The function that’s being called.
1122 func: Operand<'tcx>,
1123 /// Arguments the function is called with.
1124 /// These are owned by the callee, which is free to modify them.
1125 /// This allows the memory occupied by "by-value" arguments to be
1126 /// reused across function calls without duplicating the contents.
1127 args: Vec<Operand<'tcx>>,
1128 /// Destination for the return value. If some, the call is converging.
1129 destination: Option<(Place<'tcx>, BasicBlock)>,
1130 /// Cleanups to be done if the call unwinds.
1131 cleanup: Option<BasicBlock>,
1132 /// `true` if this is from a call in HIR rather than from an overloaded
1133 /// operator. True for overloaded function call.
1134 from_hir_call: bool,
1137 /// Jump to the target if the condition has the expected value,
1138 /// otherwise panic with a message and a cleanup target.
1140 cond: Operand<'tcx>,
1142 msg: AssertMessage<'tcx>,
1144 cleanup: Option<BasicBlock>,
1147 /// A suspend point.
1149 /// The value to return.
1150 value: Operand<'tcx>,
1151 /// Where to resume to.
1153 /// Cleanup to be done if the generator is dropped at this suspend point.
1154 drop: Option<BasicBlock>,
1157 /// Indicates the end of the dropping of a generator.
1160 /// A block where control flow only ever takes one real path, but borrowck
1161 /// needs to be more conservative.
1163 /// The target normal control flow will take.
1164 real_target: BasicBlock,
1165 /// A block control flow could conceptually jump to, but won't in
1167 imaginary_target: BasicBlock,
1169 /// A terminator for blocks that only take one path in reality, but where we
1170 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1171 /// This can arise in infinite loops with no function calls for example.
1173 /// The target normal control flow will take.
1174 real_target: BasicBlock,
1175 /// The imaginary cleanup block link. This particular path will never be taken
1176 /// in practice, but in order to avoid fragility we want to always
1177 /// consider it in borrowck. We don't want to accept programs which
1178 /// pass borrowck only when `panic=abort` or some assertions are disabled
1179 /// due to release vs. debug mode builds. This needs to be an `Option` because
1180 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1181 unwind: Option<BasicBlock>,
1185 pub type Successors<'a> =
1186 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1187 pub type SuccessorsMut<'a> =
1188 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1190 impl<'tcx> Terminator<'tcx> {
1191 pub fn successors(&self) -> Successors<'_> {
1192 self.kind.successors()
1195 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1196 self.kind.successors_mut()
1199 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1203 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1204 self.kind.unwind_mut()
1208 impl<'tcx> TerminatorKind<'tcx> {
1211 cond: Operand<'tcx>,
1214 ) -> TerminatorKind<'tcx> {
1215 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1216 TerminatorKind::SwitchInt {
1218 switch_ty: tcx.types.bool,
1219 values: From::from(BOOL_SWITCH_FALSE),
1220 targets: vec![f, t],
1224 pub fn successors(&self) -> Successors<'_> {
1225 use self::TerminatorKind::*;
1232 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1233 Goto { target: ref t }
1234 | Call { destination: None, cleanup: Some(ref t), .. }
1235 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1236 | Yield { resume: ref t, drop: None, .. }
1237 | DropAndReplace { target: ref t, unwind: None, .. }
1238 | Drop { target: ref t, unwind: None, .. }
1239 | Assert { target: ref t, cleanup: None, .. }
1240 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1241 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1242 | Yield { resume: ref t, drop: Some(ref u), .. }
1243 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1244 | Drop { target: ref t, unwind: Some(ref u), .. }
1245 | Assert { target: ref t, cleanup: Some(ref u), .. }
1246 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1247 Some(t).into_iter().chain(slice::from_ref(u))
1249 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1250 FalseEdges { ref real_target, ref imaginary_target } => {
1251 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1256 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1257 use self::TerminatorKind::*;
1264 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1265 Goto { target: ref mut t }
1266 | Call { destination: None, cleanup: Some(ref mut t), .. }
1267 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1268 | Yield { resume: ref mut t, drop: None, .. }
1269 | DropAndReplace { target: ref mut t, unwind: None, .. }
1270 | Drop { target: ref mut t, unwind: None, .. }
1271 | Assert { target: ref mut t, cleanup: None, .. }
1272 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1273 Some(t).into_iter().chain(&mut [])
1275 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1276 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1277 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1278 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1279 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1280 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1281 Some(t).into_iter().chain(slice::from_mut(u))
1283 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1284 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1285 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1290 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1292 TerminatorKind::Goto { .. }
1293 | TerminatorKind::Resume
1294 | TerminatorKind::Abort
1295 | TerminatorKind::Return
1296 | TerminatorKind::Unreachable
1297 | TerminatorKind::GeneratorDrop
1298 | TerminatorKind::Yield { .. }
1299 | TerminatorKind::SwitchInt { .. }
1300 | TerminatorKind::FalseEdges { .. } => None,
1301 TerminatorKind::Call { cleanup: ref unwind, .. }
1302 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1303 | TerminatorKind::DropAndReplace { ref unwind, .. }
1304 | TerminatorKind::Drop { ref unwind, .. }
1305 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1309 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1311 TerminatorKind::Goto { .. }
1312 | TerminatorKind::Resume
1313 | TerminatorKind::Abort
1314 | TerminatorKind::Return
1315 | TerminatorKind::Unreachable
1316 | TerminatorKind::GeneratorDrop
1317 | TerminatorKind::Yield { .. }
1318 | TerminatorKind::SwitchInt { .. }
1319 | TerminatorKind::FalseEdges { .. } => None,
1320 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1321 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1322 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1323 | TerminatorKind::Drop { ref mut unwind, .. }
1324 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1329 impl<'tcx> BasicBlockData<'tcx> {
1330 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1331 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1334 /// Accessor for terminator.
1336 /// Terminator may not be None after construction of the basic block is complete. This accessor
1337 /// provides a convenience way to reach the terminator.
1338 pub fn terminator(&self) -> &Terminator<'tcx> {
1339 self.terminator.as_ref().expect("invalid terminator state")
1342 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1343 self.terminator.as_mut().expect("invalid terminator state")
1346 pub fn retain_statements<F>(&mut self, mut f: F)
1348 F: FnMut(&mut Statement<'_>) -> bool,
1350 for s in &mut self.statements {
1357 pub fn expand_statements<F, I>(&mut self, mut f: F)
1359 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1360 I: iter::TrustedLen<Item = Statement<'tcx>>,
1362 // Gather all the iterators we'll need to splice in, and their positions.
1363 let mut splices: Vec<(usize, I)> = vec![];
1364 let mut extra_stmts = 0;
1365 for (i, s) in self.statements.iter_mut().enumerate() {
1366 if let Some(mut new_stmts) = f(s) {
1367 if let Some(first) = new_stmts.next() {
1368 // We can already store the first new statement.
1371 // Save the other statements for optimized splicing.
1372 let remaining = new_stmts.size_hint().0;
1374 splices.push((i + 1 + extra_stmts, new_stmts));
1375 extra_stmts += remaining;
1383 // Splice in the new statements, from the end of the block.
1384 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1385 // where a range of elements ("gap") is left uninitialized, with
1386 // splicing adding new elements to the end of that gap and moving
1387 // existing elements from before the gap to the end of the gap.
1388 // For now, this is safe code, emulating a gap but initializing it.
1389 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1390 self.statements.resize(
1393 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1394 kind: StatementKind::Nop,
1397 for (splice_start, new_stmts) in splices.into_iter().rev() {
1398 let splice_end = splice_start + new_stmts.size_hint().0;
1399 while gap.end > splice_end {
1402 self.statements.swap(gap.start, gap.end);
1404 self.statements.splice(splice_start..splice_end, new_stmts);
1405 gap.end = splice_start;
1409 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1410 if index < self.statements.len() {
1411 &self.statements[index]
1418 impl<'tcx> Debug for TerminatorKind<'tcx> {
1419 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1420 self.fmt_head(fmt)?;
1421 let successor_count = self.successors().count();
1422 let labels = self.fmt_successor_labels();
1423 assert_eq!(successor_count, labels.len());
1425 match successor_count {
1428 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1431 write!(fmt, " -> [")?;
1432 for (i, target) in self.successors().enumerate() {
1436 write!(fmt, "{}: {:?}", labels[i], target)?;
1444 impl<'tcx> TerminatorKind<'tcx> {
1445 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1446 /// successor basic block, if any. The only information not included is the list of possible
1447 /// successors, which may be rendered differently between the text and the graphviz format.
1448 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1449 use self::TerminatorKind::*;
1451 Goto { .. } => write!(fmt, "goto"),
1452 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1453 Return => write!(fmt, "return"),
1454 GeneratorDrop => write!(fmt, "generator_drop"),
1455 Resume => write!(fmt, "resume"),
1456 Abort => write!(fmt, "abort"),
1457 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1458 Unreachable => write!(fmt, "unreachable"),
1459 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1460 DropAndReplace { ref location, ref value, .. } => {
1461 write!(fmt, "replace({:?} <- {:?})", location, value)
1463 Call { ref func, ref args, ref destination, .. } => {
1464 if let Some((ref destination, _)) = *destination {
1465 write!(fmt, "{:?} = ", destination)?;
1467 write!(fmt, "{:?}(", func)?;
1468 for (index, arg) in args.iter().enumerate() {
1472 write!(fmt, "{:?}", arg)?;
1476 Assert { ref cond, expected, ref msg, .. } => {
1477 write!(fmt, "assert(")?;
1481 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1483 FalseEdges { .. } => write!(fmt, "falseEdges"),
1484 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1488 /// Returns the list of labels for the edges to the successor basic blocks.
1489 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1490 use self::TerminatorKind::*;
1492 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1493 Goto { .. } => vec!["".into()],
1494 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1495 let param_env = ty::ParamEnv::empty();
1496 let switch_ty = tcx.lift(&switch_ty).unwrap();
1497 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1501 ty::Const::from_scalar(
1503 Scalar::from_uint(u, size).into(),
1509 .chain(iter::once("otherwise".into()))
1512 Call { destination: Some(_), cleanup: Some(_), .. } => {
1513 vec!["return".into(), "unwind".into()]
1515 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1516 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1517 Call { destination: None, cleanup: None, .. } => vec![],
1518 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1519 Yield { drop: None, .. } => vec!["resume".into()],
1520 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1521 vec!["return".into()]
1523 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1524 vec!["return".into(), "unwind".into()]
1526 Assert { cleanup: None, .. } => vec!["".into()],
1527 Assert { .. } => vec!["success".into(), "unwind".into()],
1528 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1529 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1530 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1535 ///////////////////////////////////////////////////////////////////////////
1538 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1539 pub struct Statement<'tcx> {
1540 pub source_info: SourceInfo,
1541 pub kind: StatementKind<'tcx>,
1544 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1545 #[cfg(target_arch = "x86_64")]
1546 static_assert_size!(Statement<'_>, 32);
1548 impl Statement<'_> {
1549 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1550 /// invalidating statement indices in `Location`s.
1551 pub fn make_nop(&mut self) {
1552 self.kind = StatementKind::Nop
1555 /// Changes a statement to a nop and returns the original statement.
1556 pub fn replace_nop(&mut self) -> Self {
1558 source_info: self.source_info,
1559 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1564 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1565 pub enum StatementKind<'tcx> {
1566 /// Write the RHS Rvalue to the LHS Place.
1567 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1569 /// This represents all the reading that a pattern match may do
1570 /// (e.g., inspecting constants and discriminant values), and the
1571 /// kind of pattern it comes from. This is in order to adapt potential
1572 /// error messages to these specific patterns.
1574 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1575 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1576 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1578 /// Write the discriminant for a variant to the enum Place.
1579 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1581 /// Start a live range for the storage of the local.
1584 /// End the current live range for the storage of the local.
1587 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1588 /// of `StatementKind` low.
1589 InlineAsm(Box<InlineAsm<'tcx>>),
1591 /// Retag references in the given place, ensuring they got fresh tags. This is
1592 /// part of the Stacked Borrows model. These statements are currently only interpreted
1593 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1594 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1595 /// for more details.
1596 Retag(RetagKind, Box<Place<'tcx>>),
1598 /// Encodes a user's type ascription. These need to be preserved
1599 /// intact so that NLL can respect them. For example:
1603 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1604 /// to the user-given type `T`. The effect depends on the specified variance:
1606 /// - `Covariant` -- requires that `T_y <: T`
1607 /// - `Contravariant` -- requires that `T_y :> T`
1608 /// - `Invariant` -- requires that `T_y == T`
1609 /// - `Bivariant` -- no effect
1610 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1612 /// No-op. Useful for deleting instructions without affecting statement indices.
1616 /// Describes what kind of retag is to be performed.
1617 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1618 pub enum RetagKind {
1619 /// The initial retag when entering a function.
1621 /// Retag preparing for a two-phase borrow.
1623 /// Retagging raw pointers.
1625 /// A "normal" retag.
1629 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1630 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable, PartialEq)]
1631 pub enum FakeReadCause {
1632 /// Inject a fake read of the borrowed input at the end of each guards
1635 /// This should ensure that you cannot change the variant for an enum while
1636 /// you are in the midst of matching on it.
1639 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1640 /// generate a read of x to check that it is initialized and safe.
1643 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1644 /// in a match guard to ensure that it's value hasn't change by the time
1645 /// we create the OutsideGuard version.
1648 /// Officially, the semantics of
1650 /// `let pattern = <expr>;`
1652 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1653 /// into the pattern.
1655 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1656 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1657 /// but in some cases it can affect the borrow checker, as in #53695.
1658 /// Therefore, we insert a "fake read" here to ensure that we get
1659 /// appropriate errors.
1662 /// If we have an index expression like
1664 /// (*x)[1][{ x = y; 4}]
1666 /// then the first bounds check is invalidated when we evaluate the second
1667 /// index expression. Thus we create a fake borrow of `x` across the second
1668 /// indexer, which will cause a borrow check error.
1672 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1673 pub struct InlineAsm<'tcx> {
1674 pub asm: hir::InlineAsmInner,
1675 pub outputs: Box<[Place<'tcx>]>,
1676 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1679 impl Debug for Statement<'_> {
1680 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1681 use self::StatementKind::*;
1683 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1684 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1685 Retag(ref kind, ref place) => write!(
1689 RetagKind::FnEntry => "[fn entry] ",
1690 RetagKind::TwoPhase => "[2phase] ",
1691 RetagKind::Raw => "[raw] ",
1692 RetagKind::Default => "",
1696 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1697 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1698 SetDiscriminant { ref place, variant_index } => {
1699 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1701 InlineAsm(ref asm) => {
1702 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1704 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1705 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1707 Nop => write!(fmt, "nop"),
1712 ///////////////////////////////////////////////////////////////////////////
1715 /// A path to a value; something that can be evaluated without
1716 /// changing or disturbing program state.
1718 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1720 pub struct Place<'tcx> {
1721 pub base: PlaceBase<'tcx>,
1723 /// projection out of a place (access a field, deref a pointer, etc)
1724 pub projection: &'tcx List<PlaceElem<'tcx>>,
1727 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1730 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1732 pub enum PlaceBase<'tcx> {
1736 /// static or static mut variable
1737 Static(Box<Static<'tcx>>),
1740 /// We store the normalized type to avoid requiring normalization when reading MIR
1741 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
1742 RustcEncodable, RustcDecodable, HashStable)]
1743 pub struct Static<'tcx> {
1745 pub kind: StaticKind<'tcx>,
1746 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1747 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1748 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1749 /// into the calling frame.
1754 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1756 pub enum StaticKind<'tcx> {
1757 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1758 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1759 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1760 Promoted(Promoted, SubstsRef<'tcx>),
1764 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1765 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1766 pub enum ProjectionElem<V, T> {
1771 /// These indices are generated by slice patterns. Easiest to explain
1775 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1776 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1777 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1778 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1781 /// index or -index (in Python terms), depending on from_end
1783 /// thing being indexed must be at least this long
1785 /// counting backwards from end?
1789 /// These indices are generated by slice patterns.
1791 /// slice[from:-to] in Python terms.
1797 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1798 /// this for ADTs with more than one variant. It may be better to
1799 /// just introduce it always, or always for enums.
1801 /// The included Symbol is the name of the variant, used for printing MIR.
1802 Downcast(Option<Symbol>, VariantIdx),
1805 impl<V, T> ProjectionElem<V, T> {
1806 /// Returns `true` if the target of this projection may refer to a different region of memory
1808 fn is_indirect(&self) -> bool {
1810 Self::Deref => true,
1814 | Self::ConstantIndex { .. }
1815 | Self::Subslice { .. }
1816 | Self::Downcast(_, _)
1822 /// Alias for projections as they appear in places, where the base is a place
1823 /// and the index is a local.
1824 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1826 impl<'tcx> Copy for PlaceElem<'tcx> { }
1828 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1829 #[cfg(target_arch = "x86_64")]
1830 static_assert_size!(PlaceElem<'_>, 16);
1832 /// Alias for projections as they appear in `UserTypeProjection`, where we
1833 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1834 pub type ProjectionKind = ProjectionElem<(), ()>;
1836 rustc_index::newtype_index! {
1839 DEBUG_FORMAT = "field[{}]"
1843 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1844 pub struct PlaceRef<'a, 'tcx> {
1845 pub base: &'a PlaceBase<'tcx>,
1846 pub projection: &'a [PlaceElem<'tcx>],
1849 impl<'tcx> Place<'tcx> {
1850 // FIXME change this to a const fn by also making List::empty a const fn.
1851 pub fn return_place() -> Place<'tcx> {
1853 base: PlaceBase::Local(RETURN_PLACE),
1854 projection: List::empty(),
1858 /// Returns `true` if this `Place` contains a `Deref` projection.
1860 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1861 /// same region of memory as its base.
1862 pub fn is_indirect(&self) -> bool {
1863 self.projection.iter().any(|elem| elem.is_indirect())
1866 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1867 /// a single deref of a local.
1869 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1870 pub fn local_or_deref_local(&self) -> Option<Local> {
1871 match self.as_ref() {
1873 base: &PlaceBase::Local(local),
1877 base: &PlaceBase::Local(local),
1878 projection: &[ProjectionElem::Deref],
1884 /// If this place represents a local variable like `_X` with no
1885 /// projections, return `Some(_X)`.
1886 pub fn as_local(&self) -> Option<Local> {
1887 self.as_ref().as_local()
1890 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1893 projection: &self.projection,
1898 impl From<Local> for Place<'_> {
1899 fn from(local: Local) -> Self {
1902 projection: List::empty(),
1907 impl From<Local> for PlaceBase<'_> {
1908 fn from(local: Local) -> Self {
1909 PlaceBase::Local(local)
1913 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1914 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1915 /// a single deref of a local.
1917 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1918 pub fn local_or_deref_local(&self) -> Option<Local> {
1921 base: PlaceBase::Local(local),
1925 base: PlaceBase::Local(local),
1926 projection: [ProjectionElem::Deref],
1932 /// If this place represents a local variable like `_X` with no
1933 /// projections, return `Some(_X)`.
1934 pub fn as_local(&self) -> Option<Local> {
1936 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1942 impl Debug for Place<'_> {
1943 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1944 for elem in self.projection.iter().rev() {
1946 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1947 write!(fmt, "(").unwrap();
1949 ProjectionElem::Deref => {
1950 write!(fmt, "(*").unwrap();
1952 ProjectionElem::Index(_)
1953 | ProjectionElem::ConstantIndex { .. }
1954 | ProjectionElem::Subslice { .. } => {}
1958 write!(fmt, "{:?}", self.base)?;
1960 for elem in self.projection.iter() {
1962 ProjectionElem::Downcast(Some(name), _index) => {
1963 write!(fmt, " as {})", name)?;
1965 ProjectionElem::Downcast(None, index) => {
1966 write!(fmt, " as variant#{:?})", index)?;
1968 ProjectionElem::Deref => {
1971 ProjectionElem::Field(field, ty) => {
1972 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1974 ProjectionElem::Index(ref index) => {
1975 write!(fmt, "[{:?}]", index)?;
1977 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1978 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1980 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1981 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1983 ProjectionElem::Subslice { from, to } if *to == 0 => {
1984 write!(fmt, "[{:?}:]", from)?;
1986 ProjectionElem::Subslice { from, to } if *from == 0 => {
1987 write!(fmt, "[:-{:?}]", to)?;
1989 ProjectionElem::Subslice { from, to } => {
1990 write!(fmt, "[{:?}:-{:?}]", from, to)?;
1999 impl Debug for PlaceBase<'_> {
2000 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2002 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
2003 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
2004 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
2006 PlaceBase::Static(box self::Static {
2007 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
2009 write!(fmt, "({:?}: {:?})", promoted, ty)
2015 ///////////////////////////////////////////////////////////////////////////
2018 rustc_index::newtype_index! {
2019 pub struct SourceScope {
2021 DEBUG_FORMAT = "scope[{}]",
2022 const OUTERMOST_SOURCE_SCOPE = 0,
2026 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2027 pub struct SourceScopeData {
2029 pub parent_scope: Option<SourceScope>,
2032 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2033 pub struct SourceScopeLocalData {
2034 /// An `HirId` with lint levels equivalent to this scope's lint levels.
2035 pub lint_root: hir::HirId,
2036 /// The unsafe block that contains this node.
2040 ///////////////////////////////////////////////////////////////////////////
2043 /// These are values that can appear inside an rvalue. They are intentionally
2044 /// limited to prevent rvalues from being nested in one another.
2045 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2046 pub enum Operand<'tcx> {
2047 /// Copy: The value must be available for use afterwards.
2049 /// This implies that the type of the place must be `Copy`; this is true
2050 /// by construction during build, but also checked by the MIR type checker.
2053 /// Move: The value (including old borrows of it) will not be used again.
2055 /// Safe for values of all types (modulo future developments towards `?Move`).
2056 /// Correct usage patterns are enforced by the borrow checker for safe code.
2057 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2060 /// Synthesizes a constant value.
2061 Constant(Box<Constant<'tcx>>),
2064 impl<'tcx> Debug for Operand<'tcx> {
2065 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2066 use self::Operand::*;
2068 Constant(ref a) => write!(fmt, "{:?}", a),
2069 Copy(ref place) => write!(fmt, "{:?}", place),
2070 Move(ref place) => write!(fmt, "move {:?}", place),
2075 impl<'tcx> Operand<'tcx> {
2076 /// Convenience helper to make a constant that refers to the fn
2077 /// with given `DefId` and substs. Since this is used to synthesize
2078 /// MIR, assumes `user_ty` is None.
2079 pub fn function_handle(
2082 substs: SubstsRef<'tcx>,
2085 let ty = tcx.type_of(def_id).subst(tcx, substs);
2086 Operand::Constant(box Constant {
2089 literal: ty::Const::zero_sized(tcx, ty),
2093 pub fn to_copy(&self) -> Self {
2095 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2096 Operand::Move(ref place) => Operand::Copy(place.clone()),
2101 ///////////////////////////////////////////////////////////////////////////
2104 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2105 pub enum Rvalue<'tcx> {
2106 /// x (either a move or copy, depending on type of x)
2110 Repeat(Operand<'tcx>, u64),
2113 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2115 /// length of a [X] or [X;n] value
2118 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2120 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2121 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2123 NullaryOp(NullOp, Ty<'tcx>),
2124 UnaryOp(UnOp, Operand<'tcx>),
2126 /// Read the discriminant of an ADT.
2128 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2129 /// be defined to return, say, a 0) if ADT is not an enum.
2130 Discriminant(Place<'tcx>),
2132 /// Creates an aggregate value, like a tuple or struct. This is
2133 /// only needed because we want to distinguish `dest = Foo { x:
2134 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2135 /// that `Foo` has a destructor. These rvalues can be optimized
2136 /// away after type-checking and before lowering.
2137 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2140 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2143 Pointer(PointerCast),
2146 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2147 pub enum AggregateKind<'tcx> {
2148 /// The type is of the element
2152 /// The second field is the variant index. It's equal to 0 for struct
2153 /// and union expressions. The fourth field is
2154 /// active field number and is present only for union expressions
2155 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2156 /// active field index would identity the field `c`
2157 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2159 Closure(DefId, SubstsRef<'tcx>),
2160 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2163 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2165 /// The `+` operator (addition)
2167 /// The `-` operator (subtraction)
2169 /// The `*` operator (multiplication)
2171 /// The `/` operator (division)
2173 /// The `%` operator (modulus)
2175 /// The `^` operator (bitwise xor)
2177 /// The `&` operator (bitwise and)
2179 /// The `|` operator (bitwise or)
2181 /// The `<<` operator (shift left)
2183 /// The `>>` operator (shift right)
2185 /// The `==` operator (equality)
2187 /// The `<` operator (less than)
2189 /// The `<=` operator (less than or equal to)
2191 /// The `!=` operator (not equal to)
2193 /// The `>=` operator (greater than or equal to)
2195 /// The `>` operator (greater than)
2197 /// The `ptr.offset` operator
2202 pub fn is_checkable(self) -> bool {
2205 Add | Sub | Mul | Shl | Shr => true,
2211 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2213 /// Returns the size of a value of that type
2215 /// Creates a new uninitialized box for a value of that type
2219 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2221 /// The `!` operator for logical inversion
2223 /// The `-` operator for negation
2227 impl<'tcx> Debug for Rvalue<'tcx> {
2228 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2229 use self::Rvalue::*;
2232 Use(ref place) => write!(fmt, "{:?}", place),
2233 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2234 Len(ref a) => write!(fmt, "Len({:?})", a),
2235 Cast(ref kind, ref place, ref ty) => {
2236 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2238 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2239 CheckedBinaryOp(ref op, ref a, ref b) => {
2240 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2242 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2243 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2244 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2245 Ref(region, borrow_kind, ref place) => {
2246 let kind_str = match borrow_kind {
2247 BorrowKind::Shared => "",
2248 BorrowKind::Shallow => "shallow ",
2249 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2252 // When printing regions, add trailing space if necessary.
2253 let print_region = ty::tls::with(|tcx| {
2254 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2256 let region = if print_region {
2257 let mut region = region.to_string();
2258 if region.len() > 0 {
2263 // Do not even print 'static
2266 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2269 Aggregate(ref kind, ref places) => {
2270 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2271 let mut tuple_fmt = fmt.debug_tuple("");
2272 for place in places {
2273 tuple_fmt.field(place);
2279 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2281 AggregateKind::Tuple => match places.len() {
2282 0 => write!(fmt, "()"),
2283 1 => write!(fmt, "({:?},)", places[0]),
2284 _ => fmt_tuple(fmt, places),
2287 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2288 let variant_def = &adt_def.variants[variant];
2291 ty::tls::with(|tcx| {
2292 let substs = tcx.lift(&substs).expect("could not lift for printing");
2293 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2294 .print_def_path(variant_def.def_id, substs)?;
2298 match variant_def.ctor_kind {
2299 CtorKind::Const => Ok(()),
2300 CtorKind::Fn => fmt_tuple(fmt, places),
2301 CtorKind::Fictive => {
2302 let mut struct_fmt = fmt.debug_struct("");
2303 for (field, place) in variant_def.fields.iter().zip(places) {
2304 struct_fmt.field(&field.ident.as_str(), place);
2311 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2312 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2313 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2314 format!("[closure@{:?}]", hir_id)
2316 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2318 let mut struct_fmt = fmt.debug_struct(&name);
2320 if let Some(upvars) = tcx.upvars(def_id) {
2321 for (&var_id, place) in upvars.keys().zip(places) {
2322 let var_name = tcx.hir().name(var_id);
2323 struct_fmt.field(&var_name.as_str(), place);
2329 write!(fmt, "[closure]")
2333 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2334 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2335 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2336 let mut struct_fmt = fmt.debug_struct(&name);
2338 if let Some(upvars) = tcx.upvars(def_id) {
2339 for (&var_id, place) in upvars.keys().zip(places) {
2340 let var_name = tcx.hir().name(var_id);
2341 struct_fmt.field(&var_name.as_str(), place);
2347 write!(fmt, "[generator]")
2356 ///////////////////////////////////////////////////////////////////////////
2359 /// Two constants are equal if they are the same constant. Note that
2360 /// this does not necessarily mean that they are "==" in Rust -- in
2361 /// particular one must be wary of `NaN`!
2363 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2364 pub struct Constant<'tcx> {
2367 /// Optional user-given type: for something like
2368 /// `collect::<Vec<_>>`, this would be present and would
2369 /// indicate that `Vec<_>` was explicitly specified.
2371 /// Needed for NLL to impose user-given type constraints.
2372 pub user_ty: Option<UserTypeAnnotationIndex>,
2374 pub literal: &'tcx ty::Const<'tcx>,
2377 impl Constant<'tcx> {
2378 pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
2379 match self.literal.val.try_to_scalar() {
2380 Some(Scalar::Ptr(ptr)) => match tcx.alloc_map.lock().get(ptr.alloc_id) {
2381 Some(GlobalAlloc::Static(def_id)) => Some(def_id),
2384 tcx.sess.delay_span_bug(
2385 DUMMY_SP, "MIR cannot contain dangling const pointers",
2395 /// A collection of projections into user types.
2397 /// They are projections because a binding can occur a part of a
2398 /// parent pattern that has been ascribed a type.
2400 /// Its a collection because there can be multiple type ascriptions on
2401 /// the path from the root of the pattern down to the binding itself.
2406 /// struct S<'a>((i32, &'a str), String);
2407 /// let S((_, w): (i32, &'static str), _): S = ...;
2408 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2409 /// // --------------------------------- ^ (2)
2412 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2413 /// ascribed the type `(i32, &'static str)`.
2415 /// The highlights labelled `(2)` show the whole pattern being
2416 /// ascribed the type `S`.
2418 /// In this example, when we descend to `w`, we will have built up the
2419 /// following two projected types:
2421 /// * base: `S`, projection: `(base.0).1`
2422 /// * base: `(i32, &'static str)`, projection: `base.1`
2424 /// The first will lead to the constraint `w: &'1 str` (for some
2425 /// inferred region `'1`). The second will lead to the constraint `w:
2427 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2428 pub struct UserTypeProjections {
2429 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2432 impl<'tcx> UserTypeProjections {
2433 pub fn none() -> Self {
2434 UserTypeProjections { contents: vec![] }
2437 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2438 UserTypeProjections { contents: projs.collect() }
2441 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2442 self.contents.iter()
2445 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2446 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2449 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2450 self.contents.push((user_ty.clone(), span));
2456 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2458 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2462 pub fn index(self) -> Self {
2463 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2466 pub fn subslice(self, from: u32, to: u32) -> Self {
2467 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2470 pub fn deref(self) -> Self {
2471 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2474 pub fn leaf(self, field: Field) -> Self {
2475 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2478 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2479 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2483 /// Encodes the effect of a user-supplied type annotation on the
2484 /// subcomponents of a pattern. The effect is determined by applying the
2485 /// given list of proejctions to some underlying base type. Often,
2486 /// the projection element list `projs` is empty, in which case this
2487 /// directly encodes a type in `base`. But in the case of complex patterns with
2488 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2489 /// in which case the `projs` vector is used.
2493 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2495 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2496 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2497 /// determined by finding the type of the `.0` field from `T`.
2498 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2499 pub struct UserTypeProjection {
2500 pub base: UserTypeAnnotationIndex,
2501 pub projs: Vec<ProjectionKind>,
2504 impl Copy for ProjectionKind {}
2506 impl UserTypeProjection {
2507 pub(crate) fn index(mut self) -> Self {
2508 self.projs.push(ProjectionElem::Index(()));
2512 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2513 self.projs.push(ProjectionElem::Subslice { from, to });
2517 pub(crate) fn deref(mut self) -> Self {
2518 self.projs.push(ProjectionElem::Deref);
2522 pub(crate) fn leaf(mut self, field: Field) -> Self {
2523 self.projs.push(ProjectionElem::Field(field, ()));
2527 pub(crate) fn variant(
2529 adt_def: &'tcx AdtDef,
2530 variant_index: VariantIdx,
2533 self.projs.push(ProjectionElem::Downcast(
2534 Some(adt_def.variants[variant_index].ident.name),
2537 self.projs.push(ProjectionElem::Field(field, ()));
2542 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2544 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2545 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2546 use crate::mir::ProjectionElem::*;
2548 let base = self.base.fold_with(folder);
2549 let projs: Vec<_> = self
2552 .map(|elem| match elem {
2554 Field(f, ()) => Field(f.clone(), ()),
2555 Index(()) => Index(()),
2556 elem => elem.clone(),
2560 UserTypeProjection { base, projs }
2563 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2564 self.base.visit_with(visitor)
2565 // Note: there's nothing in `self.proj` to visit.
2569 rustc_index::newtype_index! {
2570 pub struct Promoted {
2572 DEBUG_FORMAT = "promoted[{}]"
2576 impl<'tcx> Debug for Constant<'tcx> {
2577 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2578 write!(fmt, "{}", self)
2582 impl<'tcx> Display for Constant<'tcx> {
2583 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2584 write!(fmt, "const ")?;
2585 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2586 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2587 // detailed and just not '{pointer}'.
2588 if let ty::RawPtr(_) = self.literal.ty.kind {
2589 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2591 write!(fmt, "{}", self.literal)
2596 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2597 type Node = BasicBlock;
2600 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2601 fn num_nodes(&self) -> usize {
2602 self.basic_blocks.len()
2606 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2607 fn start_node(&self) -> Self::Node {
2612 impl<'tcx> graph::WithPredecessors for Body<'tcx> {
2616 ) -> <Self as GraphPredecessors<'_>>::Iter {
2617 self.predecessors_for(node).clone().into_iter()
2621 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2625 ) -> <Self as GraphSuccessors<'_>>::Iter {
2626 self.basic_blocks[node].terminator().successors().cloned()
2630 impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
2631 type Item = BasicBlock;
2632 type Iter = IntoIter<BasicBlock>;
2635 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2636 type Item = BasicBlock;
2637 type Iter = iter::Cloned<Successors<'b>>;
2640 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2641 pub struct Location {
2642 /// The block that the location is within.
2643 pub block: BasicBlock,
2645 /// The location is the position of the start of the statement; or, if
2646 /// `statement_index` equals the number of statements, then the start of the
2648 pub statement_index: usize,
2651 impl fmt::Debug for Location {
2652 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2653 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2658 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2660 /// Returns the location immediately after this one within the enclosing block.
2662 /// Note that if this location represents a terminator, then the
2663 /// resulting location would be out of bounds and invalid.
2664 pub fn successor_within_block(&self) -> Location {
2665 Location { block: self.block, statement_index: self.statement_index + 1 }
2668 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2669 pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
2670 // If we are in the same block as the other location and are an earlier statement
2671 // then we are a predecessor of `other`.
2672 if self.block == other.block && self.statement_index < other.statement_index {
2676 // If we're in another block, then we want to check that block is a predecessor of `other`.
2677 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).clone();
2678 let mut visited = FxHashSet::default();
2680 while let Some(block) = queue.pop() {
2681 // If we haven't visited this block before, then make sure we visit it's predecessors.
2682 if visited.insert(block) {
2683 queue.append(&mut body.predecessors_for(block).clone());
2688 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2689 // we found that block by looking at the predecessors of `other`).
2690 if self.block == block {
2698 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2699 if self.block == other.block {
2700 self.statement_index <= other.statement_index
2702 dominators.is_dominated_by(other.block, self.block)
2707 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2708 pub enum UnsafetyViolationKind {
2710 /// Permitted both in `const fn`s and regular `fn`s.
2712 BorrowPacked(hir::HirId),
2715 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2716 pub struct UnsafetyViolation {
2717 pub source_info: SourceInfo,
2718 pub description: Symbol,
2719 pub details: Symbol,
2720 pub kind: UnsafetyViolationKind,
2723 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2724 pub struct UnsafetyCheckResult {
2725 /// Violations that are propagated *upwards* from this function.
2726 pub violations: Lrc<[UnsafetyViolation]>,
2727 /// `unsafe` blocks in this function, along with whether they are used. This is
2728 /// used for the "unused_unsafe" lint.
2729 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2732 rustc_index::newtype_index! {
2733 pub struct GeneratorSavedLocal {
2735 DEBUG_FORMAT = "_{}",
2739 /// The layout of generator state.
2740 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2741 pub struct GeneratorLayout<'tcx> {
2742 /// The type of every local stored inside the generator.
2743 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2745 /// Which of the above fields are in each variant. Note that one field may
2746 /// be stored in multiple variants.
2747 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2749 /// Which saved locals are storage-live at the same time. Locals that do not
2750 /// have conflicts with each other are allowed to overlap in the computed
2752 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2755 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2756 pub struct BorrowCheckResult<'tcx> {
2757 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2758 pub used_mut_upvars: SmallVec<[Field; 8]>,
2761 /// The result of the `mir_const_qualif` query.
2763 /// Each field corresponds to an implementer of the `Qualif` trait in
2764 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2766 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2767 pub struct ConstQualifs {
2768 pub has_mut_interior: bool,
2769 pub needs_drop: bool,
2772 /// After we borrow check a closure, we are left with various
2773 /// requirements that we have inferred between the free regions that
2774 /// appear in the closure's signature or on its field types. These
2775 /// requirements are then verified and proved by the closure's
2776 /// creating function. This struct encodes those requirements.
2778 /// The requirements are listed as being between various
2779 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2780 /// vids refer to the free regions that appear in the closure (or
2781 /// generator's) type, in order of appearance. (This numbering is
2782 /// actually defined by the `UniversalRegions` struct in the NLL
2783 /// region checker. See for example
2784 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2785 /// regions in the closure's type "as if" they were erased, so their
2786 /// precise identity is not important, only their position.
2788 /// Example: If type check produces a closure with the closure substs:
2791 /// ClosureSubsts = [
2792 /// i8, // the "closure kind"
2793 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2794 /// &'a String, // some upvar
2798 /// here, there is one unique free region (`'a`) but it appears
2799 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2802 /// ClosureSubsts = [
2803 /// i8, // the "closure kind"
2804 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2805 /// &'2 String, // some upvar
2809 /// Now the code might impose a requirement like `'1: '2`. When an
2810 /// instance of the closure is created, the corresponding free regions
2811 /// can be extracted from its type and constrained to have the given
2812 /// outlives relationship.
2814 /// In some cases, we have to record outlives requirements between
2815 /// types and regions as well. In that case, if those types include
2816 /// any regions, those regions are recorded as `ReClosureBound`
2817 /// instances assigned one of these same indices. Those regions will
2818 /// be substituted away by the creator. We use `ReClosureBound` in
2819 /// that case because the regions must be allocated in the global
2820 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2821 /// internally within the rest of the NLL code).
2822 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2823 pub struct ClosureRegionRequirements<'tcx> {
2824 /// The number of external regions defined on the closure. In our
2825 /// example above, it would be 3 -- one for `'static`, then `'1`
2826 /// and `'2`. This is just used for a sanity check later on, to
2827 /// make sure that the number of regions we see at the callsite
2829 pub num_external_vids: usize,
2831 /// Requirements between the various free regions defined in
2833 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2836 /// Indicates an outlives-constraint between a type or between two
2837 /// free regions declared on the closure.
2838 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2839 pub struct ClosureOutlivesRequirement<'tcx> {
2840 // This region or type ...
2841 pub subject: ClosureOutlivesSubject<'tcx>,
2843 // ... must outlive this one.
2844 pub outlived_free_region: ty::RegionVid,
2846 // If not, report an error here ...
2847 pub blame_span: Span,
2849 // ... due to this reason.
2850 pub category: ConstraintCategory,
2853 /// Outlives-constraints can be categorized to determine whether and why they
2854 /// are interesting (for error reporting). Order of variants indicates sort
2855 /// order of the category, thereby influencing diagnostic output.
2857 /// See also [rustc_mir::borrow_check::nll::constraints].
2871 pub enum ConstraintCategory {
2879 /// A constraint that came from checking the body of a closure.
2881 /// We try to get the category that the closure used when reporting this.
2889 /// A "boring" constraint (caused by the given location) is one that
2890 /// the user probably doesn't want to see described in diagnostics,
2891 /// because it is kind of an artifact of the type system setup.
2892 /// Example: `x = Foo { field: y }` technically creates
2893 /// intermediate regions representing the "type of `Foo { field: y
2894 /// }`", and data flows from `y` into those variables, but they
2895 /// are not very interesting. The assignment into `x` on the other
2898 // Boring and applicable everywhere.
2901 /// A constraint that doesn't correspond to anything the user sees.
2905 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2906 /// that must outlive some region.
2907 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2908 pub enum ClosureOutlivesSubject<'tcx> {
2909 /// Subject is a type, typically a type parameter, but could also
2910 /// be a projection. Indicates a requirement like `T: 'a` being
2911 /// passed to the caller, where the type here is `T`.
2913 /// The type here is guaranteed not to contain any free regions at
2917 /// Subject is a free region from the closure. Indicates a requirement
2918 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2919 Region(ty::RegionVid),
2923 * `TypeFoldable` implementations for MIR types
2926 CloneTypeFoldableAndLiftImpls! {
2935 SourceScopeLocalData,
2936 UserTypeAnnotationIndex,
2939 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2940 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2941 use crate::mir::TerminatorKind::*;
2943 let kind = match self.kind {
2944 Goto { target } => Goto { target },
2945 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2946 discr: discr.fold_with(folder),
2947 switch_ty: switch_ty.fold_with(folder),
2948 values: values.clone(),
2949 targets: targets.clone(),
2951 Drop { ref location, target, unwind } => {
2952 Drop { location: location.fold_with(folder), target, unwind }
2954 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2955 location: location.fold_with(folder),
2956 value: value.fold_with(folder),
2960 Yield { ref value, resume, drop } => {
2961 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2963 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2965 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2968 func: func.fold_with(folder),
2969 args: args.fold_with(folder),
2975 Assert { ref cond, expected, ref msg, target, cleanup } => {
2977 let msg = match msg {
2978 BoundsCheck { ref len, ref index } =>
2980 len: len.fold_with(folder),
2981 index: index.fold_with(folder),
2983 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2984 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2987 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2989 GeneratorDrop => GeneratorDrop,
2993 Unreachable => Unreachable,
2994 FalseEdges { real_target, imaginary_target } => {
2995 FalseEdges { real_target, imaginary_target }
2997 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
2999 Terminator { source_info: self.source_info, kind }
3002 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3003 use crate::mir::TerminatorKind::*;
3006 SwitchInt { ref discr, switch_ty, .. } => {
3007 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
3009 Drop { ref location, .. } => location.visit_with(visitor),
3010 DropAndReplace { ref location, ref value, .. } => {
3011 location.visit_with(visitor) || value.visit_with(visitor)
3013 Yield { ref value, .. } => value.visit_with(visitor),
3014 Call { ref func, ref args, ref destination, .. } => {
3015 let dest = if let Some((ref loc, _)) = *destination {
3016 loc.visit_with(visitor)
3020 dest || func.visit_with(visitor) || args.visit_with(visitor)
3022 Assert { ref cond, ref msg, .. } => {
3023 if cond.visit_with(visitor) {
3026 BoundsCheck { ref len, ref index } =>
3027 len.visit_with(visitor) || index.visit_with(visitor),
3028 Panic { .. } | Overflow(_) | OverflowNeg |
3029 DivisionByZero | RemainderByZero |
3030 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
3044 | FalseUnwind { .. } => false,
3049 impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
3050 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3054 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3059 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3060 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3062 base: self.base.fold_with(folder),
3063 projection: self.projection.fold_with(folder),
3067 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3068 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3072 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3073 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3075 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3076 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3080 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3082 PlaceBase::Local(local) => local.visit_with(visitor),
3083 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3088 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3089 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3090 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3091 folder.tcx().intern_place_elems(&v)
3094 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3095 self.iter().any(|t| t.visit_with(visitor))
3099 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3100 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3102 ty: self.ty.fold_with(folder),
3103 kind: self.kind.fold_with(folder),
3104 def_id: self.def_id,
3108 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3109 let Static { ty, kind, def_id: _ } = self;
3111 ty.visit_with(visitor) || kind.visit_with(visitor)
3115 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3116 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3118 StaticKind::Promoted(promoted, substs) =>
3119 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3120 StaticKind::Static => StaticKind::Static
3124 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3126 StaticKind::Promoted(promoted, substs) =>
3127 promoted.visit_with(visitor) || substs.visit_with(visitor),
3128 StaticKind::Static => { false }
3133 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3134 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3135 use crate::mir::Rvalue::*;
3137 Use(ref op) => Use(op.fold_with(folder)),
3138 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3139 Ref(region, bk, ref place) => {
3140 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3142 Len(ref place) => Len(place.fold_with(folder)),
3143 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3144 BinaryOp(op, ref rhs, ref lhs) => {
3145 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3147 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3148 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3150 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3151 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3152 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3153 Aggregate(ref kind, ref fields) => {
3154 let kind = box match **kind {
3155 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3156 AggregateKind::Tuple => AggregateKind::Tuple,
3157 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3160 substs.fold_with(folder),
3161 user_ty.fold_with(folder),
3164 AggregateKind::Closure(id, substs) => {
3165 AggregateKind::Closure(id, substs.fold_with(folder))
3167 AggregateKind::Generator(id, substs, movablity) => {
3168 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3171 Aggregate(kind, fields.fold_with(folder))
3176 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3177 use crate::mir::Rvalue::*;
3179 Use(ref op) => op.visit_with(visitor),
3180 Repeat(ref op, _) => op.visit_with(visitor),
3181 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3182 Len(ref place) => place.visit_with(visitor),
3183 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3184 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3185 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3187 UnaryOp(_, ref val) => val.visit_with(visitor),
3188 Discriminant(ref place) => place.visit_with(visitor),
3189 NullaryOp(_, ty) => ty.visit_with(visitor),
3190 Aggregate(ref kind, ref fields) => {
3192 AggregateKind::Array(ty) => ty.visit_with(visitor),
3193 AggregateKind::Tuple => false,
3194 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3195 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3197 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3198 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3199 }) || fields.visit_with(visitor)
3205 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3206 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3208 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3209 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3210 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3214 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3216 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3217 Operand::Constant(ref c) => c.visit_with(visitor),
3222 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3223 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3224 use crate::mir::ProjectionElem::*;
3228 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3229 Index(v) => Index(v.fold_with(folder)),
3230 elem => elem.clone(),
3234 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3235 use crate::mir::ProjectionElem::*;
3238 Field(_, ty) => ty.visit_with(visitor),
3239 Index(v) => v.visit_with(visitor),
3245 impl<'tcx> TypeFoldable<'tcx> for Field {
3246 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3249 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3254 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3255 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3258 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3263 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3264 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3267 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3272 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3273 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3275 span: self.span.clone(),
3276 user_ty: self.user_ty.fold_with(folder),
3277 literal: self.literal.fold_with(folder),
3280 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3281 self.literal.visit_with(visitor)