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: IndexVec<SourceScope, ClearCrossCrate<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: IndexVec<SourceScope, ClearCrossCrate<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 as_ref(&'a self) -> ClearCrossCrate<&'a T> {
440 ClearCrossCrate::Clear => ClearCrossCrate::Clear,
441 ClearCrossCrate::Set(v) => ClearCrossCrate::Set(v),
445 pub fn assert_crate_local(self) -> T {
447 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
448 ClearCrossCrate::Set(v) => v,
453 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
454 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
456 /// Grouped information about the source code origin of a MIR entity.
457 /// Intended to be inspected by diagnostics and debuginfo.
458 /// Most passes can work with it as a whole, within a single function.
459 // The unofficial Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
460 // `Hash`. Please ping @bjorn3 if removing them.
461 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
462 pub struct SourceInfo {
463 /// The source span for the AST pertaining to this MIR entity.
466 /// The source scope, keeping track of which bindings can be
467 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
468 pub scope: SourceScope,
471 ///////////////////////////////////////////////////////////////////////////
472 // Mutability and borrow kinds
474 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
475 pub enum Mutability {
480 impl From<Mutability> for hir::Mutability {
481 fn from(m: Mutability) -> Self {
483 Mutability::Mut => hir::Mutability::Mutable,
484 Mutability::Not => hir::Mutability::Immutable,
490 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
492 pub enum BorrowKind {
493 /// Data must be immutable and is aliasable.
496 /// The immediately borrowed place must be immutable, but projections from
497 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
498 /// conflict with a mutable borrow of `a.b.c`.
500 /// This is used when lowering matches: when matching on a place we want to
501 /// ensure that place have the same value from the start of the match until
502 /// an arm is selected. This prevents this code from compiling:
504 /// let mut x = &Some(0);
507 /// Some(_) if { x = &None; false } => (),
511 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
512 /// should not prevent `if let None = x { ... }`, for example, because the
513 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
514 /// We can also report errors with this kind of borrow differently.
517 /// Data must be immutable but not aliasable. This kind of borrow
518 /// cannot currently be expressed by the user and is used only in
519 /// implicit closure bindings. It is needed when the closure is
520 /// borrowing or mutating a mutable referent, e.g.:
522 /// let x: &mut isize = ...;
523 /// let y = || *x += 5;
525 /// If we were to try to translate this closure into a more explicit
526 /// form, we'd encounter an error with the code as written:
528 /// struct Env { x: & &mut isize }
529 /// let x: &mut isize = ...;
530 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
531 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
533 /// This is then illegal because you cannot mutate an `&mut` found
534 /// in an aliasable location. To solve, you'd have to translate with
535 /// an `&mut` borrow:
537 /// struct Env { x: & &mut isize }
538 /// let x: &mut isize = ...;
539 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
540 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
542 /// Now the assignment to `**env.x` is legal, but creating a
543 /// mutable pointer to `x` is not because `x` is not mutable. We
544 /// could fix this by declaring `x` as `let mut x`. This is ok in
545 /// user code, if awkward, but extra weird for closures, since the
546 /// borrow is hidden.
548 /// So we introduce a "unique imm" borrow -- the referent is
549 /// immutable, but not aliasable. This solves the problem. For
550 /// simplicity, we don't give users the way to express this
551 /// borrow, it's just used when translating closures.
554 /// Data is mutable and not aliasable.
556 /// `true` if this borrow arose from method-call auto-ref
557 /// (i.e., `adjustment::Adjust::Borrow`).
558 allow_two_phase_borrow: bool,
563 pub fn allows_two_phase_borrow(&self) -> bool {
565 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
566 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
571 ///////////////////////////////////////////////////////////////////////////
572 // Variables and temps
574 rustc_index::newtype_index! {
577 DEBUG_FORMAT = "_{}",
578 const RETURN_PLACE = 0,
582 impl Atom for Local {
583 fn index(self) -> usize {
588 /// Classifies locals into categories. See `Body::local_kind`.
589 #[derive(PartialEq, Eq, Debug, HashStable)]
591 /// User-declared variable binding.
593 /// Compiler-introduced temporary.
595 /// Function argument.
597 /// Location of function's return value.
601 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
602 pub struct VarBindingForm<'tcx> {
603 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
604 pub binding_mode: ty::BindingMode,
605 /// If an explicit type was provided for this variable binding,
606 /// this holds the source Span of that type.
608 /// NOTE: if you want to change this to a `HirId`, be wary that
609 /// doing so breaks incremental compilation (as of this writing),
610 /// while a `Span` does not cause our tests to fail.
611 pub opt_ty_info: Option<Span>,
612 /// Place of the RHS of the =, or the subject of the `match` where this
613 /// variable is initialized. None in the case of `let PATTERN;`.
614 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
615 /// (a) the right-hand side isn't evaluated as a place expression.
616 /// (b) it gives a way to separate this case from the remaining cases
618 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
619 /// The span of the pattern in which this variable was bound.
623 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
624 pub enum BindingForm<'tcx> {
625 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
626 Var(VarBindingForm<'tcx>),
627 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
628 ImplicitSelf(ImplicitSelfKind),
629 /// Reference used in a guard expression to ensure immutability.
633 /// Represents what type of implicit self a function has, if any.
634 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable, HashStable)]
635 pub enum ImplicitSelfKind {
636 /// Represents a `fn x(self);`.
638 /// Represents a `fn x(mut self);`.
640 /// Represents a `fn x(&self);`.
642 /// Represents a `fn x(&mut self);`.
644 /// Represents when a function does not have a self argument or
645 /// when a function has a `self: X` argument.
649 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
651 mod binding_form_impl {
652 use crate::ich::StableHashingContext;
653 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
655 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
656 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
657 use super::BindingForm::*;
658 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
661 Var(binding) => binding.hash_stable(hcx, hasher),
662 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
669 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
670 /// created during evaluation of expressions in a block tail
671 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
673 /// It is used to improve diagnostics when such temporaries are
674 /// involved in borrow_check errors, e.g., explanations of where the
675 /// temporaries come from, when their destructors are run, and/or how
676 /// one might revise the code to satisfy the borrow checker's rules.
677 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
678 pub struct BlockTailInfo {
679 /// If `true`, then the value resulting from evaluating this tail
680 /// expression is ignored by the block's expression context.
682 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
683 /// but not e.g., `let _x = { ...; tail };`
684 pub tail_result_is_ignored: bool,
689 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
690 /// argument, or the return place.
691 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
692 pub struct LocalDecl<'tcx> {
693 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
695 /// Temporaries and the return place are always mutable.
696 pub mutability: Mutability,
698 // FIXME(matthewjasper) Don't store in this in `Body`
699 pub local_info: LocalInfo<'tcx>,
701 /// `true` if this is an internal local.
703 /// These locals are not based on types in the source code and are only used
704 /// for a few desugarings at the moment.
706 /// The generator transformation will sanity check the locals which are live
707 /// across a suspension point against the type components of the generator
708 /// which type checking knows are live across a suspension point. We need to
709 /// flag drop flags to avoid triggering this check as they are introduced
712 /// Unsafety checking will also ignore dereferences of these locals,
713 /// so they can be used for raw pointers only used in a desugaring.
715 /// This should be sound because the drop flags are fully algebraic, and
716 /// therefore don't affect the OIBIT or outlives properties of the
720 /// If this local is a temporary and `is_block_tail` is `Some`,
721 /// then it is a temporary created for evaluation of some
722 /// subexpression of some block's tail expression (with no
723 /// intervening statement context).
724 // FIXME(matthewjasper) Don't store in this in `Body`
725 pub is_block_tail: Option<BlockTailInfo>,
727 /// The type of this local.
730 /// If the user manually ascribed a type to this variable,
731 /// e.g., via `let x: T`, then we carry that type here. The MIR
732 /// borrow checker needs this information since it can affect
733 /// region inference.
734 // FIXME(matthewjasper) Don't store in this in `Body`
735 pub user_ty: UserTypeProjections,
737 /// The *syntactic* (i.e., not visibility) source scope the local is defined
738 /// in. If the local was defined in a let-statement, this
739 /// is *within* the let-statement, rather than outside
742 /// This is needed because the visibility source scope of locals within
743 /// a let-statement is weird.
745 /// The reason is that we want the local to be *within* the let-statement
746 /// for lint purposes, but we want the local to be *after* the let-statement
747 /// for names-in-scope purposes.
749 /// That's it, if we have a let-statement like the one in this
753 /// fn foo(x: &str) {
754 /// #[allow(unused_mut)]
755 /// let mut x: u32 = { // <- one unused mut
756 /// let mut y: u32 = x.parse().unwrap();
763 /// Then, from a lint point of view, the declaration of `x: u32`
764 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
765 /// lint scopes are the same as the AST/HIR nesting.
767 /// However, from a name lookup point of view, the scopes look more like
768 /// as if the let-statements were `match` expressions:
771 /// fn foo(x: &str) {
773 /// match x.parse().unwrap() {
782 /// We care about the name-lookup scopes for debuginfo - if the
783 /// debuginfo instruction pointer is at the call to `x.parse()`, we
784 /// want `x` to refer to `x: &str`, but if it is at the call to
785 /// `drop(x)`, we want it to refer to `x: u32`.
787 /// To allow both uses to work, we need to have more than a single scope
788 /// for a local. We have the `source_info.scope` represent the "syntactic"
789 /// lint scope (with a variable being under its let block) while the
790 /// `var_debug_info.source_info.scope` represents the "local variable"
791 /// scope (where the "rest" of a block is under all prior let-statements).
793 /// The end result looks like this:
797 /// │{ argument x: &str }
799 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
800 /// │ │ // in practice because I'm lazy.
802 /// │ │← x.source_info.scope
803 /// │ │← `x.parse().unwrap()`
805 /// │ │ │← y.source_info.scope
807 /// │ │ │{ let y: u32 }
809 /// │ │ │← y.var_debug_info.source_info.scope
812 /// │ │{ let x: u32 }
813 /// │ │← x.var_debug_info.source_info.scope
814 /// │ │← `drop(x)` // This accesses `x: u32`.
816 pub source_info: SourceInfo,
819 /// Extra information about a local that's used for diagnostics.
820 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
821 pub enum LocalInfo<'tcx> {
822 /// A user-defined local variable or function parameter
824 /// The `BindingForm` is solely used for local diagnostics when generating
825 /// warnings/errors when compiling the current crate, and therefore it need
826 /// not be visible across crates.
827 User(ClearCrossCrate<BindingForm<'tcx>>),
828 /// A temporary created that references the static with the given `DefId`.
829 StaticRef { def_id: DefId, is_thread_local: bool },
830 /// Any other temporary, the return place, or an anonymous function parameter.
834 impl<'tcx> LocalDecl<'tcx> {
835 /// Returns `true` only if local is a binding that can itself be
836 /// made mutable via the addition of the `mut` keyword, namely
837 /// something like the occurrences of `x` in:
838 /// - `fn foo(x: Type) { ... }`,
840 /// - or `match ... { C(x) => ... }`
841 pub fn can_be_made_mutable(&self) -> bool {
842 match self.local_info {
843 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
844 binding_mode: ty::BindingMode::BindByValue(_),
851 ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)),
858 /// Returns `true` if local is definitely not a `ref ident` or
859 /// `ref mut ident` binding. (Such bindings cannot be made into
860 /// mutable bindings, but the inverse does not necessarily hold).
861 pub fn is_nonref_binding(&self) -> bool {
862 match self.local_info {
863 LocalInfo::User(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
864 binding_mode: ty::BindingMode::BindByValue(_),
870 LocalInfo::User(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
876 /// Returns `true` if this variable is a named variable or function
877 /// parameter declared by the user.
879 pub fn is_user_variable(&self) -> bool {
880 match self.local_info {
881 LocalInfo::User(_) => true,
886 /// Returns `true` if this is a reference to a variable bound in a `match`
887 /// expression that is used to access said variable for the guard of the
889 pub fn is_ref_for_guard(&self) -> bool {
890 match self.local_info {
891 LocalInfo::User(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
896 /// Returns `Some` if this is a reference to a static item that is used to
897 /// access that static
898 pub fn is_ref_to_static(&self) -> bool {
899 match self.local_info {
900 LocalInfo::StaticRef { .. } => true,
905 /// Returns `Some` if this is a reference to a static item that is used to
906 /// access that static
907 pub fn is_ref_to_thread_local(&self) -> bool {
908 match self.local_info {
909 LocalInfo::StaticRef { is_thread_local, .. } => is_thread_local,
914 /// Returns `true` is the local is from a compiler desugaring, e.g.,
915 /// `__next` from a `for` loop.
917 pub fn from_compiler_desugaring(&self) -> bool {
918 self.source_info.span.desugaring_kind().is_some()
921 /// Creates a new `LocalDecl` for a temporary.
923 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
924 Self::new_local(ty, Mutability::Mut, false, span)
927 /// Converts `self` into same `LocalDecl` except tagged as immutable.
929 pub fn immutable(mut self) -> Self {
930 self.mutability = Mutability::Not;
934 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
936 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
937 assert!(self.is_block_tail.is_none());
938 self.is_block_tail = Some(info);
942 /// Creates a new `LocalDecl` for a internal temporary.
944 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
945 Self::new_local(ty, Mutability::Mut, true, span)
949 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
953 user_ty: UserTypeProjections::none(),
954 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
956 local_info: LocalInfo::Other,
961 /// Builds a `LocalDecl` for the return place.
963 /// This must be inserted into the `local_decls` list as the first local.
965 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
967 mutability: Mutability::Mut,
969 user_ty: UserTypeProjections::none(),
970 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
973 local_info: LocalInfo::Other,
978 /// Debug information pertaining to a user variable.
979 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
980 pub struct VarDebugInfo<'tcx> {
983 /// Source info of the user variable, including the scope
984 /// within which the variable is visible (to debuginfo)
985 /// (see `LocalDecl`'s `source_info` field for more details).
986 pub source_info: SourceInfo,
988 /// Where the data for this user variable is to be found.
989 /// NOTE(eddyb) There's an unenforced invariant that this `Place` is
990 /// based on a `Local`, not a `Static`, and contains no indexing.
991 pub place: Place<'tcx>,
994 ///////////////////////////////////////////////////////////////////////////
997 rustc_index::newtype_index! {
998 pub struct BasicBlock {
1000 DEBUG_FORMAT = "bb{}",
1001 const START_BLOCK = 0,
1006 pub fn start_location(self) -> Location {
1007 Location { block: self, statement_index: 0 }
1011 ///////////////////////////////////////////////////////////////////////////
1012 // BasicBlockData and Terminator
1014 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1015 pub struct BasicBlockData<'tcx> {
1016 /// List of statements in this block.
1017 pub statements: Vec<Statement<'tcx>>,
1019 /// Terminator for this block.
1021 /// N.B., this should generally ONLY be `None` during construction.
1022 /// Therefore, you should generally access it via the
1023 /// `terminator()` or `terminator_mut()` methods. The only
1024 /// exception is that certain passes, such as `simplify_cfg`, swap
1025 /// out the terminator temporarily with `None` while they continue
1026 /// to recurse over the set of basic blocks.
1027 pub terminator: Option<Terminator<'tcx>>,
1029 /// If true, this block lies on an unwind path. This is used
1030 /// during codegen where distinct kinds of basic blocks may be
1031 /// generated (particularly for MSVC cleanup). Unwind blocks must
1032 /// only branch to other unwind blocks.
1033 pub is_cleanup: bool,
1036 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1037 pub struct Terminator<'tcx> {
1038 pub source_info: SourceInfo,
1039 pub kind: TerminatorKind<'tcx>,
1042 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
1043 pub enum TerminatorKind<'tcx> {
1044 /// Block should have one successor in the graph; we jump there.
1045 Goto { target: BasicBlock },
1047 /// Operand evaluates to an integer; jump depending on its value
1048 /// to one of the targets, and otherwise fallback to `otherwise`.
1050 /// The discriminant value being tested.
1051 discr: Operand<'tcx>,
1053 /// The type of value being tested.
1054 switch_ty: Ty<'tcx>,
1056 /// Possible values. The locations to branch to in each case
1057 /// are found in the corresponding indices from the `targets` vector.
1058 values: Cow<'tcx, [u128]>,
1060 /// Possible branch sites. The last element of this vector is used
1061 /// for the otherwise branch, so targets.len() == values.len() + 1
1064 // This invariant is quite non-obvious and also could be improved.
1065 // One way to make this invariant is to have something like this instead:
1067 // branches: Vec<(ConstInt, BasicBlock)>,
1068 // otherwise: Option<BasicBlock> // exhaustive if None
1070 // However we’ve decided to keep this as-is until we figure a case
1071 // where some other approach seems to be strictly better than other.
1072 targets: Vec<BasicBlock>,
1075 /// Indicates that the landing pad is finished and unwinding should
1076 /// continue. Emitted by `build::scope::diverge_cleanup`.
1079 /// Indicates that the landing pad is finished and that the process
1080 /// should abort. Used to prevent unwinding for foreign items.
1083 /// Indicates a normal return. The return place should have
1084 /// been filled in by now. This should occur at most once.
1087 /// Indicates a terminator that can never be reached.
1090 /// Drop the `Place`.
1091 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1093 /// Drop the `Place` and assign the new value over it. This ensures
1094 /// that the assignment to `P` occurs *even if* the destructor for
1095 /// place unwinds. Its semantics are best explained by the
1100 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1108 /// Drop(P, goto BB1, unwind BB2)
1111 /// // P is now uninitialized
1115 /// // P is now uninitialized -- its dtor panicked
1120 location: Place<'tcx>,
1121 value: Operand<'tcx>,
1123 unwind: Option<BasicBlock>,
1126 /// Block ends with a call of a converging function.
1128 /// The function that’s being called.
1129 func: Operand<'tcx>,
1130 /// Arguments the function is called with.
1131 /// These are owned by the callee, which is free to modify them.
1132 /// This allows the memory occupied by "by-value" arguments to be
1133 /// reused across function calls without duplicating the contents.
1134 args: Vec<Operand<'tcx>>,
1135 /// Destination for the return value. If some, the call is converging.
1136 destination: Option<(Place<'tcx>, BasicBlock)>,
1137 /// Cleanups to be done if the call unwinds.
1138 cleanup: Option<BasicBlock>,
1139 /// `true` if this is from a call in HIR rather than from an overloaded
1140 /// operator. True for overloaded function call.
1141 from_hir_call: bool,
1144 /// Jump to the target if the condition has the expected value,
1145 /// otherwise panic with a message and a cleanup target.
1147 cond: Operand<'tcx>,
1149 msg: AssertMessage<'tcx>,
1151 cleanup: Option<BasicBlock>,
1154 /// A suspend point.
1156 /// The value to return.
1157 value: Operand<'tcx>,
1158 /// Where to resume to.
1160 /// Cleanup to be done if the generator is dropped at this suspend point.
1161 drop: Option<BasicBlock>,
1164 /// Indicates the end of the dropping of a generator.
1167 /// A block where control flow only ever takes one real path, but borrowck
1168 /// needs to be more conservative.
1170 /// The target normal control flow will take.
1171 real_target: BasicBlock,
1172 /// A block control flow could conceptually jump to, but won't in
1174 imaginary_target: BasicBlock,
1176 /// A terminator for blocks that only take one path in reality, but where we
1177 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1178 /// This can arise in infinite loops with no function calls for example.
1180 /// The target normal control flow will take.
1181 real_target: BasicBlock,
1182 /// The imaginary cleanup block link. This particular path will never be taken
1183 /// in practice, but in order to avoid fragility we want to always
1184 /// consider it in borrowck. We don't want to accept programs which
1185 /// pass borrowck only when `panic=abort` or some assertions are disabled
1186 /// due to release vs. debug mode builds. This needs to be an `Option` because
1187 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1188 unwind: Option<BasicBlock>,
1192 pub type Successors<'a> =
1193 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1194 pub type SuccessorsMut<'a> =
1195 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1197 impl<'tcx> Terminator<'tcx> {
1198 pub fn successors(&self) -> Successors<'_> {
1199 self.kind.successors()
1202 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1203 self.kind.successors_mut()
1206 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1210 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1211 self.kind.unwind_mut()
1215 impl<'tcx> TerminatorKind<'tcx> {
1218 cond: Operand<'tcx>,
1221 ) -> TerminatorKind<'tcx> {
1222 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1223 TerminatorKind::SwitchInt {
1225 switch_ty: tcx.types.bool,
1226 values: From::from(BOOL_SWITCH_FALSE),
1227 targets: vec![f, t],
1231 pub fn successors(&self) -> Successors<'_> {
1232 use self::TerminatorKind::*;
1239 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1240 Goto { target: ref t }
1241 | Call { destination: None, cleanup: Some(ref t), .. }
1242 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1243 | Yield { resume: ref t, drop: None, .. }
1244 | DropAndReplace { target: ref t, unwind: None, .. }
1245 | Drop { target: ref t, unwind: None, .. }
1246 | Assert { target: ref t, cleanup: None, .. }
1247 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1248 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1249 | Yield { resume: ref t, drop: Some(ref u), .. }
1250 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1251 | Drop { target: ref t, unwind: Some(ref u), .. }
1252 | Assert { target: ref t, cleanup: Some(ref u), .. }
1253 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1254 Some(t).into_iter().chain(slice::from_ref(u))
1256 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1257 FalseEdges { ref real_target, ref imaginary_target } => {
1258 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1263 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1264 use self::TerminatorKind::*;
1271 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1272 Goto { target: ref mut t }
1273 | Call { destination: None, cleanup: Some(ref mut t), .. }
1274 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1275 | Yield { resume: ref mut t, drop: None, .. }
1276 | DropAndReplace { target: ref mut t, unwind: None, .. }
1277 | Drop { target: ref mut t, unwind: None, .. }
1278 | Assert { target: ref mut t, cleanup: None, .. }
1279 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1280 Some(t).into_iter().chain(&mut [])
1282 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1283 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1284 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1285 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1286 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1287 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1288 Some(t).into_iter().chain(slice::from_mut(u))
1290 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1291 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1292 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1297 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1299 TerminatorKind::Goto { .. }
1300 | TerminatorKind::Resume
1301 | TerminatorKind::Abort
1302 | TerminatorKind::Return
1303 | TerminatorKind::Unreachable
1304 | TerminatorKind::GeneratorDrop
1305 | TerminatorKind::Yield { .. }
1306 | TerminatorKind::SwitchInt { .. }
1307 | TerminatorKind::FalseEdges { .. } => None,
1308 TerminatorKind::Call { cleanup: ref unwind, .. }
1309 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1310 | TerminatorKind::DropAndReplace { ref unwind, .. }
1311 | TerminatorKind::Drop { ref unwind, .. }
1312 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1316 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1318 TerminatorKind::Goto { .. }
1319 | TerminatorKind::Resume
1320 | TerminatorKind::Abort
1321 | TerminatorKind::Return
1322 | TerminatorKind::Unreachable
1323 | TerminatorKind::GeneratorDrop
1324 | TerminatorKind::Yield { .. }
1325 | TerminatorKind::SwitchInt { .. }
1326 | TerminatorKind::FalseEdges { .. } => None,
1327 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1328 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1329 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1330 | TerminatorKind::Drop { ref mut unwind, .. }
1331 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1336 impl<'tcx> BasicBlockData<'tcx> {
1337 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1338 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1341 /// Accessor for terminator.
1343 /// Terminator may not be None after construction of the basic block is complete. This accessor
1344 /// provides a convenience way to reach the terminator.
1345 pub fn terminator(&self) -> &Terminator<'tcx> {
1346 self.terminator.as_ref().expect("invalid terminator state")
1349 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1350 self.terminator.as_mut().expect("invalid terminator state")
1353 pub fn retain_statements<F>(&mut self, mut f: F)
1355 F: FnMut(&mut Statement<'_>) -> bool,
1357 for s in &mut self.statements {
1364 pub fn expand_statements<F, I>(&mut self, mut f: F)
1366 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1367 I: iter::TrustedLen<Item = Statement<'tcx>>,
1369 // Gather all the iterators we'll need to splice in, and their positions.
1370 let mut splices: Vec<(usize, I)> = vec![];
1371 let mut extra_stmts = 0;
1372 for (i, s) in self.statements.iter_mut().enumerate() {
1373 if let Some(mut new_stmts) = f(s) {
1374 if let Some(first) = new_stmts.next() {
1375 // We can already store the first new statement.
1378 // Save the other statements for optimized splicing.
1379 let remaining = new_stmts.size_hint().0;
1381 splices.push((i + 1 + extra_stmts, new_stmts));
1382 extra_stmts += remaining;
1390 // Splice in the new statements, from the end of the block.
1391 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1392 // where a range of elements ("gap") is left uninitialized, with
1393 // splicing adding new elements to the end of that gap and moving
1394 // existing elements from before the gap to the end of the gap.
1395 // For now, this is safe code, emulating a gap but initializing it.
1396 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1397 self.statements.resize(
1400 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1401 kind: StatementKind::Nop,
1404 for (splice_start, new_stmts) in splices.into_iter().rev() {
1405 let splice_end = splice_start + new_stmts.size_hint().0;
1406 while gap.end > splice_end {
1409 self.statements.swap(gap.start, gap.end);
1411 self.statements.splice(splice_start..splice_end, new_stmts);
1412 gap.end = splice_start;
1416 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1417 if index < self.statements.len() {
1418 &self.statements[index]
1425 impl<'tcx> Debug for TerminatorKind<'tcx> {
1426 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1427 self.fmt_head(fmt)?;
1428 let successor_count = self.successors().count();
1429 let labels = self.fmt_successor_labels();
1430 assert_eq!(successor_count, labels.len());
1432 match successor_count {
1435 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1438 write!(fmt, " -> [")?;
1439 for (i, target) in self.successors().enumerate() {
1443 write!(fmt, "{}: {:?}", labels[i], target)?;
1451 impl<'tcx> TerminatorKind<'tcx> {
1452 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1453 /// successor basic block, if any. The only information not included is the list of possible
1454 /// successors, which may be rendered differently between the text and the graphviz format.
1455 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1456 use self::TerminatorKind::*;
1458 Goto { .. } => write!(fmt, "goto"),
1459 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1460 Return => write!(fmt, "return"),
1461 GeneratorDrop => write!(fmt, "generator_drop"),
1462 Resume => write!(fmt, "resume"),
1463 Abort => write!(fmt, "abort"),
1464 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1465 Unreachable => write!(fmt, "unreachable"),
1466 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1467 DropAndReplace { ref location, ref value, .. } => {
1468 write!(fmt, "replace({:?} <- {:?})", location, value)
1470 Call { ref func, ref args, ref destination, .. } => {
1471 if let Some((ref destination, _)) = *destination {
1472 write!(fmt, "{:?} = ", destination)?;
1474 write!(fmt, "{:?}(", func)?;
1475 for (index, arg) in args.iter().enumerate() {
1479 write!(fmt, "{:?}", arg)?;
1483 Assert { ref cond, expected, ref msg, .. } => {
1484 write!(fmt, "assert(")?;
1488 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1490 FalseEdges { .. } => write!(fmt, "falseEdges"),
1491 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1495 /// Returns the list of labels for the edges to the successor basic blocks.
1496 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1497 use self::TerminatorKind::*;
1499 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1500 Goto { .. } => vec!["".into()],
1501 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1502 let param_env = ty::ParamEnv::empty();
1503 let switch_ty = tcx.lift(&switch_ty).unwrap();
1504 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1508 ty::Const::from_scalar(
1510 Scalar::from_uint(u, size).into(),
1516 .chain(iter::once("otherwise".into()))
1519 Call { destination: Some(_), cleanup: Some(_), .. } => {
1520 vec!["return".into(), "unwind".into()]
1522 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1523 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1524 Call { destination: None, cleanup: None, .. } => vec![],
1525 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1526 Yield { drop: None, .. } => vec!["resume".into()],
1527 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1528 vec!["return".into()]
1530 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1531 vec!["return".into(), "unwind".into()]
1533 Assert { cleanup: None, .. } => vec!["".into()],
1534 Assert { .. } => vec!["success".into(), "unwind".into()],
1535 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1536 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1537 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1542 ///////////////////////////////////////////////////////////////////////////
1545 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1546 pub struct Statement<'tcx> {
1547 pub source_info: SourceInfo,
1548 pub kind: StatementKind<'tcx>,
1551 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1552 #[cfg(target_arch = "x86_64")]
1553 static_assert_size!(Statement<'_>, 32);
1555 impl Statement<'_> {
1556 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1557 /// invalidating statement indices in `Location`s.
1558 pub fn make_nop(&mut self) {
1559 self.kind = StatementKind::Nop
1562 /// Changes a statement to a nop and returns the original statement.
1563 pub fn replace_nop(&mut self) -> Self {
1565 source_info: self.source_info,
1566 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1571 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1572 pub enum StatementKind<'tcx> {
1573 /// Write the RHS Rvalue to the LHS Place.
1574 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1576 /// This represents all the reading that a pattern match may do
1577 /// (e.g., inspecting constants and discriminant values), and the
1578 /// kind of pattern it comes from. This is in order to adapt potential
1579 /// error messages to these specific patterns.
1581 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1582 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1583 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1585 /// Write the discriminant for a variant to the enum Place.
1586 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1588 /// Start a live range for the storage of the local.
1591 /// End the current live range for the storage of the local.
1594 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1595 /// of `StatementKind` low.
1596 InlineAsm(Box<InlineAsm<'tcx>>),
1598 /// Retag references in the given place, ensuring they got fresh tags. This is
1599 /// part of the Stacked Borrows model. These statements are currently only interpreted
1600 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1601 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1602 /// for more details.
1603 Retag(RetagKind, Box<Place<'tcx>>),
1605 /// Encodes a user's type ascription. These need to be preserved
1606 /// intact so that NLL can respect them. For example:
1610 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1611 /// to the user-given type `T`. The effect depends on the specified variance:
1613 /// - `Covariant` -- requires that `T_y <: T`
1614 /// - `Contravariant` -- requires that `T_y :> T`
1615 /// - `Invariant` -- requires that `T_y == T`
1616 /// - `Bivariant` -- no effect
1617 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1619 /// No-op. Useful for deleting instructions without affecting statement indices.
1623 /// Describes what kind of retag is to be performed.
1624 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1625 pub enum RetagKind {
1626 /// The initial retag when entering a function.
1628 /// Retag preparing for a two-phase borrow.
1630 /// Retagging raw pointers.
1632 /// A "normal" retag.
1636 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1637 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable, PartialEq)]
1638 pub enum FakeReadCause {
1639 /// Inject a fake read of the borrowed input at the end of each guards
1642 /// This should ensure that you cannot change the variant for an enum while
1643 /// you are in the midst of matching on it.
1646 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1647 /// generate a read of x to check that it is initialized and safe.
1650 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1651 /// in a match guard to ensure that it's value hasn't change by the time
1652 /// we create the OutsideGuard version.
1655 /// Officially, the semantics of
1657 /// `let pattern = <expr>;`
1659 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1660 /// into the pattern.
1662 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1663 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1664 /// but in some cases it can affect the borrow checker, as in #53695.
1665 /// Therefore, we insert a "fake read" here to ensure that we get
1666 /// appropriate errors.
1669 /// If we have an index expression like
1671 /// (*x)[1][{ x = y; 4}]
1673 /// then the first bounds check is invalidated when we evaluate the second
1674 /// index expression. Thus we create a fake borrow of `x` across the second
1675 /// indexer, which will cause a borrow check error.
1679 #[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1680 pub struct InlineAsm<'tcx> {
1681 pub asm: hir::InlineAsmInner,
1682 pub outputs: Box<[Place<'tcx>]>,
1683 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1686 impl Debug for Statement<'_> {
1687 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1688 use self::StatementKind::*;
1690 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1691 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1692 Retag(ref kind, ref place) => write!(
1696 RetagKind::FnEntry => "[fn entry] ",
1697 RetagKind::TwoPhase => "[2phase] ",
1698 RetagKind::Raw => "[raw] ",
1699 RetagKind::Default => "",
1703 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1704 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1705 SetDiscriminant { ref place, variant_index } => {
1706 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1708 InlineAsm(ref asm) => {
1709 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1711 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1712 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1714 Nop => write!(fmt, "nop"),
1719 ///////////////////////////////////////////////////////////////////////////
1722 /// A path to a value; something that can be evaluated without
1723 /// changing or disturbing program state.
1725 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1727 pub struct Place<'tcx> {
1728 pub base: PlaceBase<'tcx>,
1730 /// projection out of a place (access a field, deref a pointer, etc)
1731 pub projection: &'tcx List<PlaceElem<'tcx>>,
1734 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1737 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1739 pub enum PlaceBase<'tcx> {
1743 /// static or static mut variable
1744 Static(Box<Static<'tcx>>),
1747 /// We store the normalized type to avoid requiring normalization when reading MIR
1748 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
1749 RustcEncodable, RustcDecodable, HashStable)]
1750 pub struct Static<'tcx> {
1752 pub kind: StaticKind<'tcx>,
1753 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1754 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1755 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1756 /// into the calling frame.
1761 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1763 pub enum StaticKind<'tcx> {
1764 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1765 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1766 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1767 Promoted(Promoted, SubstsRef<'tcx>),
1771 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1772 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1773 pub enum ProjectionElem<V, T> {
1778 /// These indices are generated by slice patterns. Easiest to explain
1782 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1783 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1784 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1785 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1788 /// index or -index (in Python terms), depending on from_end
1790 /// thing being indexed must be at least this long
1792 /// counting backwards from end?
1796 /// These indices are generated by slice patterns.
1798 /// slice[from:-to] in Python terms.
1804 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1805 /// this for ADTs with more than one variant. It may be better to
1806 /// just introduce it always, or always for enums.
1808 /// The included Symbol is the name of the variant, used for printing MIR.
1809 Downcast(Option<Symbol>, VariantIdx),
1812 impl<V, T> ProjectionElem<V, T> {
1813 /// Returns `true` if the target of this projection may refer to a different region of memory
1815 fn is_indirect(&self) -> bool {
1817 Self::Deref => true,
1821 | Self::ConstantIndex { .. }
1822 | Self::Subslice { .. }
1823 | Self::Downcast(_, _)
1829 /// Alias for projections as they appear in places, where the base is a place
1830 /// and the index is a local.
1831 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1833 impl<'tcx> Copy for PlaceElem<'tcx> { }
1835 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1836 #[cfg(target_arch = "x86_64")]
1837 static_assert_size!(PlaceElem<'_>, 16);
1839 /// Alias for projections as they appear in `UserTypeProjection`, where we
1840 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1841 pub type ProjectionKind = ProjectionElem<(), ()>;
1843 rustc_index::newtype_index! {
1846 DEBUG_FORMAT = "field[{}]"
1850 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1851 pub struct PlaceRef<'a, 'tcx> {
1852 pub base: &'a PlaceBase<'tcx>,
1853 pub projection: &'a [PlaceElem<'tcx>],
1856 impl<'tcx> Place<'tcx> {
1857 // FIXME change this to a const fn by also making List::empty a const fn.
1858 pub fn return_place() -> Place<'tcx> {
1860 base: PlaceBase::Local(RETURN_PLACE),
1861 projection: List::empty(),
1865 /// Returns `true` if this `Place` contains a `Deref` projection.
1867 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1868 /// same region of memory as its base.
1869 pub fn is_indirect(&self) -> bool {
1870 self.projection.iter().any(|elem| elem.is_indirect())
1873 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1874 /// a single deref of a local.
1876 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1877 pub fn local_or_deref_local(&self) -> Option<Local> {
1878 match self.as_ref() {
1880 base: &PlaceBase::Local(local),
1884 base: &PlaceBase::Local(local),
1885 projection: &[ProjectionElem::Deref],
1891 /// If this place represents a local variable like `_X` with no
1892 /// projections, return `Some(_X)`.
1893 pub fn as_local(&self) -> Option<Local> {
1894 self.as_ref().as_local()
1897 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1900 projection: &self.projection,
1905 impl From<Local> for Place<'_> {
1906 fn from(local: Local) -> Self {
1909 projection: List::empty(),
1914 impl From<Local> for PlaceBase<'_> {
1915 fn from(local: Local) -> Self {
1916 PlaceBase::Local(local)
1920 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1921 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1922 /// a single deref of a local.
1924 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1925 pub fn local_or_deref_local(&self) -> Option<Local> {
1928 base: PlaceBase::Local(local),
1932 base: PlaceBase::Local(local),
1933 projection: [ProjectionElem::Deref],
1939 /// If this place represents a local variable like `_X` with no
1940 /// projections, return `Some(_X)`.
1941 pub fn as_local(&self) -> Option<Local> {
1943 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1949 impl Debug for Place<'_> {
1950 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1951 for elem in self.projection.iter().rev() {
1953 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1954 write!(fmt, "(").unwrap();
1956 ProjectionElem::Deref => {
1957 write!(fmt, "(*").unwrap();
1959 ProjectionElem::Index(_)
1960 | ProjectionElem::ConstantIndex { .. }
1961 | ProjectionElem::Subslice { .. } => {}
1965 write!(fmt, "{:?}", self.base)?;
1967 for elem in self.projection.iter() {
1969 ProjectionElem::Downcast(Some(name), _index) => {
1970 write!(fmt, " as {})", name)?;
1972 ProjectionElem::Downcast(None, index) => {
1973 write!(fmt, " as variant#{:?})", index)?;
1975 ProjectionElem::Deref => {
1978 ProjectionElem::Field(field, ty) => {
1979 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1981 ProjectionElem::Index(ref index) => {
1982 write!(fmt, "[{:?}]", index)?;
1984 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1985 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1987 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1988 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1990 ProjectionElem::Subslice { from, to } if *to == 0 => {
1991 write!(fmt, "[{:?}:]", from)?;
1993 ProjectionElem::Subslice { from, to } if *from == 0 => {
1994 write!(fmt, "[:-{:?}]", to)?;
1996 ProjectionElem::Subslice { from, to } => {
1997 write!(fmt, "[{:?}:-{:?}]", from, to)?;
2006 impl Debug for PlaceBase<'_> {
2007 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2009 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
2010 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
2011 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
2013 PlaceBase::Static(box self::Static {
2014 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
2016 write!(fmt, "({:?}: {:?})", promoted, ty)
2022 ///////////////////////////////////////////////////////////////////////////
2025 rustc_index::newtype_index! {
2026 pub struct SourceScope {
2028 DEBUG_FORMAT = "scope[{}]",
2029 const OUTERMOST_SOURCE_SCOPE = 0,
2033 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2034 pub struct SourceScopeData {
2036 pub parent_scope: Option<SourceScope>,
2039 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2040 pub struct SourceScopeLocalData {
2041 /// An `HirId` with lint levels equivalent to this scope's lint levels.
2042 pub lint_root: hir::HirId,
2043 /// The unsafe block that contains this node.
2047 ///////////////////////////////////////////////////////////////////////////
2050 /// These are values that can appear inside an rvalue. They are intentionally
2051 /// limited to prevent rvalues from being nested in one another.
2052 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2053 pub enum Operand<'tcx> {
2054 /// Copy: The value must be available for use afterwards.
2056 /// This implies that the type of the place must be `Copy`; this is true
2057 /// by construction during build, but also checked by the MIR type checker.
2060 /// Move: The value (including old borrows of it) will not be used again.
2062 /// Safe for values of all types (modulo future developments towards `?Move`).
2063 /// Correct usage patterns are enforced by the borrow checker for safe code.
2064 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2067 /// Synthesizes a constant value.
2068 Constant(Box<Constant<'tcx>>),
2071 impl<'tcx> Debug for Operand<'tcx> {
2072 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2073 use self::Operand::*;
2075 Constant(ref a) => write!(fmt, "{:?}", a),
2076 Copy(ref place) => write!(fmt, "{:?}", place),
2077 Move(ref place) => write!(fmt, "move {:?}", place),
2082 impl<'tcx> Operand<'tcx> {
2083 /// Convenience helper to make a constant that refers to the fn
2084 /// with given `DefId` and substs. Since this is used to synthesize
2085 /// MIR, assumes `user_ty` is None.
2086 pub fn function_handle(
2089 substs: SubstsRef<'tcx>,
2092 let ty = tcx.type_of(def_id).subst(tcx, substs);
2093 Operand::Constant(box Constant {
2096 literal: ty::Const::zero_sized(tcx, ty),
2100 pub fn to_copy(&self) -> Self {
2102 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2103 Operand::Move(ref place) => Operand::Copy(place.clone()),
2108 ///////////////////////////////////////////////////////////////////////////
2111 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2112 pub enum Rvalue<'tcx> {
2113 /// x (either a move or copy, depending on type of x)
2117 Repeat(Operand<'tcx>, u64),
2120 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2122 /// length of a [X] or [X;n] value
2125 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2127 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2128 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2130 NullaryOp(NullOp, Ty<'tcx>),
2131 UnaryOp(UnOp, Operand<'tcx>),
2133 /// Read the discriminant of an ADT.
2135 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2136 /// be defined to return, say, a 0) if ADT is not an enum.
2137 Discriminant(Place<'tcx>),
2139 /// Creates an aggregate value, like a tuple or struct. This is
2140 /// only needed because we want to distinguish `dest = Foo { x:
2141 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2142 /// that `Foo` has a destructor. These rvalues can be optimized
2143 /// away after type-checking and before lowering.
2144 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2147 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2150 Pointer(PointerCast),
2153 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2154 pub enum AggregateKind<'tcx> {
2155 /// The type is of the element
2159 /// The second field is the variant index. It's equal to 0 for struct
2160 /// and union expressions. The fourth field is
2161 /// active field number and is present only for union expressions
2162 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2163 /// active field index would identity the field `c`
2164 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2166 Closure(DefId, SubstsRef<'tcx>),
2167 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2170 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2172 /// The `+` operator (addition)
2174 /// The `-` operator (subtraction)
2176 /// The `*` operator (multiplication)
2178 /// The `/` operator (division)
2180 /// The `%` operator (modulus)
2182 /// The `^` operator (bitwise xor)
2184 /// The `&` operator (bitwise and)
2186 /// The `|` operator (bitwise or)
2188 /// The `<<` operator (shift left)
2190 /// The `>>` operator (shift right)
2192 /// The `==` operator (equality)
2194 /// The `<` operator (less than)
2196 /// The `<=` operator (less than or equal to)
2198 /// The `!=` operator (not equal to)
2200 /// The `>=` operator (greater than or equal to)
2202 /// The `>` operator (greater than)
2204 /// The `ptr.offset` operator
2209 pub fn is_checkable(self) -> bool {
2212 Add | Sub | Mul | Shl | Shr => true,
2218 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2220 /// Returns the size of a value of that type
2222 /// Creates a new uninitialized box for a value of that type
2226 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2228 /// The `!` operator for logical inversion
2230 /// The `-` operator for negation
2234 impl<'tcx> Debug for Rvalue<'tcx> {
2235 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2236 use self::Rvalue::*;
2239 Use(ref place) => write!(fmt, "{:?}", place),
2240 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2241 Len(ref a) => write!(fmt, "Len({:?})", a),
2242 Cast(ref kind, ref place, ref ty) => {
2243 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2245 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2246 CheckedBinaryOp(ref op, ref a, ref b) => {
2247 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2249 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2250 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2251 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2252 Ref(region, borrow_kind, ref place) => {
2253 let kind_str = match borrow_kind {
2254 BorrowKind::Shared => "",
2255 BorrowKind::Shallow => "shallow ",
2256 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2259 // When printing regions, add trailing space if necessary.
2260 let print_region = ty::tls::with(|tcx| {
2261 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2263 let region = if print_region {
2264 let mut region = region.to_string();
2265 if region.len() > 0 {
2270 // Do not even print 'static
2273 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2276 Aggregate(ref kind, ref places) => {
2277 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2278 let mut tuple_fmt = fmt.debug_tuple("");
2279 for place in places {
2280 tuple_fmt.field(place);
2286 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2288 AggregateKind::Tuple => match places.len() {
2289 0 => write!(fmt, "()"),
2290 1 => write!(fmt, "({:?},)", places[0]),
2291 _ => fmt_tuple(fmt, places),
2294 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2295 let variant_def = &adt_def.variants[variant];
2298 ty::tls::with(|tcx| {
2299 let substs = tcx.lift(&substs).expect("could not lift for printing");
2300 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2301 .print_def_path(variant_def.def_id, substs)?;
2305 match variant_def.ctor_kind {
2306 CtorKind::Const => Ok(()),
2307 CtorKind::Fn => fmt_tuple(fmt, places),
2308 CtorKind::Fictive => {
2309 let mut struct_fmt = fmt.debug_struct("");
2310 for (field, place) in variant_def.fields.iter().zip(places) {
2311 struct_fmt.field(&field.ident.as_str(), place);
2318 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2319 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2320 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2321 format!("[closure@{:?}]", hir_id)
2323 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2325 let mut struct_fmt = fmt.debug_struct(&name);
2327 if let Some(upvars) = tcx.upvars(def_id) {
2328 for (&var_id, place) in upvars.keys().zip(places) {
2329 let var_name = tcx.hir().name(var_id);
2330 struct_fmt.field(&var_name.as_str(), place);
2336 write!(fmt, "[closure]")
2340 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2341 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2342 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2343 let mut struct_fmt = fmt.debug_struct(&name);
2345 if let Some(upvars) = tcx.upvars(def_id) {
2346 for (&var_id, place) in upvars.keys().zip(places) {
2347 let var_name = tcx.hir().name(var_id);
2348 struct_fmt.field(&var_name.as_str(), place);
2354 write!(fmt, "[generator]")
2363 ///////////////////////////////////////////////////////////////////////////
2366 /// Two constants are equal if they are the same constant. Note that
2367 /// this does not necessarily mean that they are "==" in Rust -- in
2368 /// particular one must be wary of `NaN`!
2370 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2371 pub struct Constant<'tcx> {
2374 /// Optional user-given type: for something like
2375 /// `collect::<Vec<_>>`, this would be present and would
2376 /// indicate that `Vec<_>` was explicitly specified.
2378 /// Needed for NLL to impose user-given type constraints.
2379 pub user_ty: Option<UserTypeAnnotationIndex>,
2381 pub literal: &'tcx ty::Const<'tcx>,
2384 impl Constant<'tcx> {
2385 pub fn check_static_ptr(&self, tcx: TyCtxt<'_>) -> Option<DefId> {
2386 match self.literal.val.try_to_scalar() {
2387 Some(Scalar::Ptr(ptr)) => match tcx.alloc_map.lock().get(ptr.alloc_id) {
2388 Some(GlobalAlloc::Static(def_id)) => Some(def_id),
2391 tcx.sess.delay_span_bug(
2392 DUMMY_SP, "MIR cannot contain dangling const pointers",
2402 /// A collection of projections into user types.
2404 /// They are projections because a binding can occur a part of a
2405 /// parent pattern that has been ascribed a type.
2407 /// Its a collection because there can be multiple type ascriptions on
2408 /// the path from the root of the pattern down to the binding itself.
2413 /// struct S<'a>((i32, &'a str), String);
2414 /// let S((_, w): (i32, &'static str), _): S = ...;
2415 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2416 /// // --------------------------------- ^ (2)
2419 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2420 /// ascribed the type `(i32, &'static str)`.
2422 /// The highlights labelled `(2)` show the whole pattern being
2423 /// ascribed the type `S`.
2425 /// In this example, when we descend to `w`, we will have built up the
2426 /// following two projected types:
2428 /// * base: `S`, projection: `(base.0).1`
2429 /// * base: `(i32, &'static str)`, projection: `base.1`
2431 /// The first will lead to the constraint `w: &'1 str` (for some
2432 /// inferred region `'1`). The second will lead to the constraint `w:
2434 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2435 pub struct UserTypeProjections {
2436 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2439 impl<'tcx> UserTypeProjections {
2440 pub fn none() -> Self {
2441 UserTypeProjections { contents: vec![] }
2444 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2445 UserTypeProjections { contents: projs.collect() }
2448 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2449 self.contents.iter()
2452 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2453 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2456 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2457 self.contents.push((user_ty.clone(), span));
2463 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2465 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2469 pub fn index(self) -> Self {
2470 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2473 pub fn subslice(self, from: u32, to: u32) -> Self {
2474 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2477 pub fn deref(self) -> Self {
2478 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2481 pub fn leaf(self, field: Field) -> Self {
2482 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2485 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2486 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2490 /// Encodes the effect of a user-supplied type annotation on the
2491 /// subcomponents of a pattern. The effect is determined by applying the
2492 /// given list of proejctions to some underlying base type. Often,
2493 /// the projection element list `projs` is empty, in which case this
2494 /// directly encodes a type in `base`. But in the case of complex patterns with
2495 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2496 /// in which case the `projs` vector is used.
2500 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2502 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2503 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2504 /// determined by finding the type of the `.0` field from `T`.
2505 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, PartialEq)]
2506 pub struct UserTypeProjection {
2507 pub base: UserTypeAnnotationIndex,
2508 pub projs: Vec<ProjectionKind>,
2511 impl Copy for ProjectionKind {}
2513 impl UserTypeProjection {
2514 pub(crate) fn index(mut self) -> Self {
2515 self.projs.push(ProjectionElem::Index(()));
2519 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2520 self.projs.push(ProjectionElem::Subslice { from, to });
2524 pub(crate) fn deref(mut self) -> Self {
2525 self.projs.push(ProjectionElem::Deref);
2529 pub(crate) fn leaf(mut self, field: Field) -> Self {
2530 self.projs.push(ProjectionElem::Field(field, ()));
2534 pub(crate) fn variant(
2536 adt_def: &'tcx AdtDef,
2537 variant_index: VariantIdx,
2540 self.projs.push(ProjectionElem::Downcast(
2541 Some(adt_def.variants[variant_index].ident.name),
2544 self.projs.push(ProjectionElem::Field(field, ()));
2549 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2551 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2552 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2553 use crate::mir::ProjectionElem::*;
2555 let base = self.base.fold_with(folder);
2556 let projs: Vec<_> = self
2559 .map(|elem| match elem {
2561 Field(f, ()) => Field(f.clone(), ()),
2562 Index(()) => Index(()),
2563 elem => elem.clone(),
2567 UserTypeProjection { base, projs }
2570 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2571 self.base.visit_with(visitor)
2572 // Note: there's nothing in `self.proj` to visit.
2576 rustc_index::newtype_index! {
2577 pub struct Promoted {
2579 DEBUG_FORMAT = "promoted[{}]"
2583 impl<'tcx> Debug for Constant<'tcx> {
2584 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2585 write!(fmt, "{}", self)
2589 impl<'tcx> Display for Constant<'tcx> {
2590 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2591 write!(fmt, "const ")?;
2592 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2593 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2594 // detailed and just not '{pointer}'.
2595 if let ty::RawPtr(_) = self.literal.ty.kind {
2596 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2598 write!(fmt, "{}", self.literal)
2603 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2604 type Node = BasicBlock;
2607 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2608 fn num_nodes(&self) -> usize {
2609 self.basic_blocks.len()
2613 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2614 fn start_node(&self) -> Self::Node {
2619 impl<'tcx> graph::WithPredecessors for Body<'tcx> {
2623 ) -> <Self as GraphPredecessors<'_>>::Iter {
2624 self.predecessors_for(node).clone().into_iter()
2628 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2632 ) -> <Self as GraphSuccessors<'_>>::Iter {
2633 self.basic_blocks[node].terminator().successors().cloned()
2637 impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
2638 type Item = BasicBlock;
2639 type Iter = IntoIter<BasicBlock>;
2642 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2643 type Item = BasicBlock;
2644 type Iter = iter::Cloned<Successors<'b>>;
2647 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2648 pub struct Location {
2649 /// The block that the location is within.
2650 pub block: BasicBlock,
2652 /// The location is the position of the start of the statement; or, if
2653 /// `statement_index` equals the number of statements, then the start of the
2655 pub statement_index: usize,
2658 impl fmt::Debug for Location {
2659 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2660 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2665 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2667 /// Returns the location immediately after this one within the enclosing block.
2669 /// Note that if this location represents a terminator, then the
2670 /// resulting location would be out of bounds and invalid.
2671 pub fn successor_within_block(&self) -> Location {
2672 Location { block: self.block, statement_index: self.statement_index + 1 }
2675 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2676 pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
2677 // If we are in the same block as the other location and are an earlier statement
2678 // then we are a predecessor of `other`.
2679 if self.block == other.block && self.statement_index < other.statement_index {
2683 // If we're in another block, then we want to check that block is a predecessor of `other`.
2684 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).clone();
2685 let mut visited = FxHashSet::default();
2687 while let Some(block) = queue.pop() {
2688 // If we haven't visited this block before, then make sure we visit it's predecessors.
2689 if visited.insert(block) {
2690 queue.append(&mut body.predecessors_for(block).clone());
2695 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2696 // we found that block by looking at the predecessors of `other`).
2697 if self.block == block {
2705 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2706 if self.block == other.block {
2707 self.statement_index <= other.statement_index
2709 dominators.is_dominated_by(other.block, self.block)
2714 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2715 pub enum UnsafetyViolationKind {
2717 /// Permitted both in `const fn`s and regular `fn`s.
2719 BorrowPacked(hir::HirId),
2722 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2723 pub struct UnsafetyViolation {
2724 pub source_info: SourceInfo,
2725 pub description: Symbol,
2726 pub details: Symbol,
2727 pub kind: UnsafetyViolationKind,
2730 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2731 pub struct UnsafetyCheckResult {
2732 /// Violations that are propagated *upwards* from this function.
2733 pub violations: Lrc<[UnsafetyViolation]>,
2734 /// `unsafe` blocks in this function, along with whether they are used. This is
2735 /// used for the "unused_unsafe" lint.
2736 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2739 rustc_index::newtype_index! {
2740 pub struct GeneratorSavedLocal {
2742 DEBUG_FORMAT = "_{}",
2746 /// The layout of generator state.
2747 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2748 pub struct GeneratorLayout<'tcx> {
2749 /// The type of every local stored inside the generator.
2750 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2752 /// Which of the above fields are in each variant. Note that one field may
2753 /// be stored in multiple variants.
2754 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2756 /// Which saved locals are storage-live at the same time. Locals that do not
2757 /// have conflicts with each other are allowed to overlap in the computed
2759 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2762 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2763 pub struct BorrowCheckResult<'tcx> {
2764 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2765 pub used_mut_upvars: SmallVec<[Field; 8]>,
2768 /// The result of the `mir_const_qualif` query.
2770 /// Each field corresponds to an implementer of the `Qualif` trait in
2771 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2773 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2774 pub struct ConstQualifs {
2775 pub has_mut_interior: bool,
2776 pub needs_drop: bool,
2779 /// After we borrow check a closure, we are left with various
2780 /// requirements that we have inferred between the free regions that
2781 /// appear in the closure's signature or on its field types. These
2782 /// requirements are then verified and proved by the closure's
2783 /// creating function. This struct encodes those requirements.
2785 /// The requirements are listed as being between various
2786 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2787 /// vids refer to the free regions that appear in the closure (or
2788 /// generator's) type, in order of appearance. (This numbering is
2789 /// actually defined by the `UniversalRegions` struct in the NLL
2790 /// region checker. See for example
2791 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2792 /// regions in the closure's type "as if" they were erased, so their
2793 /// precise identity is not important, only their position.
2795 /// Example: If type check produces a closure with the closure substs:
2798 /// ClosureSubsts = [
2799 /// i8, // the "closure kind"
2800 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2801 /// &'a String, // some upvar
2805 /// here, there is one unique free region (`'a`) but it appears
2806 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2809 /// ClosureSubsts = [
2810 /// i8, // the "closure kind"
2811 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2812 /// &'2 String, // some upvar
2816 /// Now the code might impose a requirement like `'1: '2`. When an
2817 /// instance of the closure is created, the corresponding free regions
2818 /// can be extracted from its type and constrained to have the given
2819 /// outlives relationship.
2821 /// In some cases, we have to record outlives requirements between
2822 /// types and regions as well. In that case, if those types include
2823 /// any regions, those regions are recorded as `ReClosureBound`
2824 /// instances assigned one of these same indices. Those regions will
2825 /// be substituted away by the creator. We use `ReClosureBound` in
2826 /// that case because the regions must be allocated in the global
2827 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2828 /// internally within the rest of the NLL code).
2829 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2830 pub struct ClosureRegionRequirements<'tcx> {
2831 /// The number of external regions defined on the closure. In our
2832 /// example above, it would be 3 -- one for `'static`, then `'1`
2833 /// and `'2`. This is just used for a sanity check later on, to
2834 /// make sure that the number of regions we see at the callsite
2836 pub num_external_vids: usize,
2838 /// Requirements between the various free regions defined in
2840 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2843 /// Indicates an outlives-constraint between a type or between two
2844 /// free regions declared on the closure.
2845 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2846 pub struct ClosureOutlivesRequirement<'tcx> {
2847 // This region or type ...
2848 pub subject: ClosureOutlivesSubject<'tcx>,
2850 // ... must outlive this one.
2851 pub outlived_free_region: ty::RegionVid,
2853 // If not, report an error here ...
2854 pub blame_span: Span,
2856 // ... due to this reason.
2857 pub category: ConstraintCategory,
2860 /// Outlives-constraints can be categorized to determine whether and why they
2861 /// are interesting (for error reporting). Order of variants indicates sort
2862 /// order of the category, thereby influencing diagnostic output.
2864 /// See also [rustc_mir::borrow_check::nll::constraints].
2878 pub enum ConstraintCategory {
2886 /// A constraint that came from checking the body of a closure.
2888 /// We try to get the category that the closure used when reporting this.
2896 /// A "boring" constraint (caused by the given location) is one that
2897 /// the user probably doesn't want to see described in diagnostics,
2898 /// because it is kind of an artifact of the type system setup.
2899 /// Example: `x = Foo { field: y }` technically creates
2900 /// intermediate regions representing the "type of `Foo { field: y
2901 /// }`", and data flows from `y` into those variables, but they
2902 /// are not very interesting. The assignment into `x` on the other
2905 // Boring and applicable everywhere.
2908 /// A constraint that doesn't correspond to anything the user sees.
2912 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2913 /// that must outlive some region.
2914 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2915 pub enum ClosureOutlivesSubject<'tcx> {
2916 /// Subject is a type, typically a type parameter, but could also
2917 /// be a projection. Indicates a requirement like `T: 'a` being
2918 /// passed to the caller, where the type here is `T`.
2920 /// The type here is guaranteed not to contain any free regions at
2924 /// Subject is a free region from the closure. Indicates a requirement
2925 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2926 Region(ty::RegionVid),
2930 * `TypeFoldable` implementations for MIR types
2933 CloneTypeFoldableAndLiftImpls! {
2942 SourceScopeLocalData,
2943 UserTypeAnnotationIndex,
2946 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2947 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2948 use crate::mir::TerminatorKind::*;
2950 let kind = match self.kind {
2951 Goto { target } => Goto { target },
2952 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2953 discr: discr.fold_with(folder),
2954 switch_ty: switch_ty.fold_with(folder),
2955 values: values.clone(),
2956 targets: targets.clone(),
2958 Drop { ref location, target, unwind } => {
2959 Drop { location: location.fold_with(folder), target, unwind }
2961 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2962 location: location.fold_with(folder),
2963 value: value.fold_with(folder),
2967 Yield { ref value, resume, drop } => {
2968 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2970 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2972 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2975 func: func.fold_with(folder),
2976 args: args.fold_with(folder),
2982 Assert { ref cond, expected, ref msg, target, cleanup } => {
2984 let msg = match msg {
2985 BoundsCheck { ref len, ref index } =>
2987 len: len.fold_with(folder),
2988 index: index.fold_with(folder),
2990 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2991 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
2994 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2996 GeneratorDrop => GeneratorDrop,
3000 Unreachable => Unreachable,
3001 FalseEdges { real_target, imaginary_target } => {
3002 FalseEdges { real_target, imaginary_target }
3004 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
3006 Terminator { source_info: self.source_info, kind }
3009 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3010 use crate::mir::TerminatorKind::*;
3013 SwitchInt { ref discr, switch_ty, .. } => {
3014 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
3016 Drop { ref location, .. } => location.visit_with(visitor),
3017 DropAndReplace { ref location, ref value, .. } => {
3018 location.visit_with(visitor) || value.visit_with(visitor)
3020 Yield { ref value, .. } => value.visit_with(visitor),
3021 Call { ref func, ref args, ref destination, .. } => {
3022 let dest = if let Some((ref loc, _)) = *destination {
3023 loc.visit_with(visitor)
3027 dest || func.visit_with(visitor) || args.visit_with(visitor)
3029 Assert { ref cond, ref msg, .. } => {
3030 if cond.visit_with(visitor) {
3033 BoundsCheck { ref len, ref index } =>
3034 len.visit_with(visitor) || index.visit_with(visitor),
3035 Panic { .. } | Overflow(_) | OverflowNeg |
3036 DivisionByZero | RemainderByZero |
3037 ResumedAfterReturn(_) | ResumedAfterPanic(_) =>
3051 | FalseUnwind { .. } => false,
3056 impl<'tcx> TypeFoldable<'tcx> for GeneratorKind {
3057 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3061 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3066 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3067 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3069 base: self.base.fold_with(folder),
3070 projection: self.projection.fold_with(folder),
3074 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3075 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3079 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3080 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3082 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3083 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3087 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3089 PlaceBase::Local(local) => local.visit_with(visitor),
3090 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3095 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3096 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3097 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3098 folder.tcx().intern_place_elems(&v)
3101 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3102 self.iter().any(|t| t.visit_with(visitor))
3106 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3107 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3109 ty: self.ty.fold_with(folder),
3110 kind: self.kind.fold_with(folder),
3111 def_id: self.def_id,
3115 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3116 let Static { ty, kind, def_id: _ } = self;
3118 ty.visit_with(visitor) || kind.visit_with(visitor)
3122 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3123 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3125 StaticKind::Promoted(promoted, substs) =>
3126 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3127 StaticKind::Static => StaticKind::Static
3131 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3133 StaticKind::Promoted(promoted, substs) =>
3134 promoted.visit_with(visitor) || substs.visit_with(visitor),
3135 StaticKind::Static => { false }
3140 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3141 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3142 use crate::mir::Rvalue::*;
3144 Use(ref op) => Use(op.fold_with(folder)),
3145 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3146 Ref(region, bk, ref place) => {
3147 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3149 Len(ref place) => Len(place.fold_with(folder)),
3150 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3151 BinaryOp(op, ref rhs, ref lhs) => {
3152 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3154 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3155 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3157 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3158 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3159 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3160 Aggregate(ref kind, ref fields) => {
3161 let kind = box match **kind {
3162 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3163 AggregateKind::Tuple => AggregateKind::Tuple,
3164 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3167 substs.fold_with(folder),
3168 user_ty.fold_with(folder),
3171 AggregateKind::Closure(id, substs) => {
3172 AggregateKind::Closure(id, substs.fold_with(folder))
3174 AggregateKind::Generator(id, substs, movablity) => {
3175 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3178 Aggregate(kind, fields.fold_with(folder))
3183 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3184 use crate::mir::Rvalue::*;
3186 Use(ref op) => op.visit_with(visitor),
3187 Repeat(ref op, _) => op.visit_with(visitor),
3188 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3189 Len(ref place) => place.visit_with(visitor),
3190 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3191 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3192 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3194 UnaryOp(_, ref val) => val.visit_with(visitor),
3195 Discriminant(ref place) => place.visit_with(visitor),
3196 NullaryOp(_, ty) => ty.visit_with(visitor),
3197 Aggregate(ref kind, ref fields) => {
3199 AggregateKind::Array(ty) => ty.visit_with(visitor),
3200 AggregateKind::Tuple => false,
3201 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3202 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3204 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3205 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3206 }) || fields.visit_with(visitor)
3212 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3213 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3215 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3216 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3217 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3221 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3223 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3224 Operand::Constant(ref c) => c.visit_with(visitor),
3229 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3230 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3231 use crate::mir::ProjectionElem::*;
3235 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3236 Index(v) => Index(v.fold_with(folder)),
3237 elem => elem.clone(),
3241 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3242 use crate::mir::ProjectionElem::*;
3245 Field(_, ty) => ty.visit_with(visitor),
3246 Index(v) => v.visit_with(visitor),
3252 impl<'tcx> TypeFoldable<'tcx> for Field {
3253 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3256 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3261 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3262 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3265 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3270 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3271 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3274 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3279 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3280 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3282 span: self.span.clone(),
3283 user_ty: self.user_ty.fold_with(folder),
3284 literal: self.literal.fold_with(folder),
3287 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3288 self.literal.visit_with(visitor)