1 // ignore-tidy-filelength
3 //! MIR datatypes and passes. See the [rustc guide] for more info.
5 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
7 use crate::hir::def::{CtorKind, Namespace};
8 use crate::hir::def_id::DefId;
9 use crate::hir::{self, InlineAsm as HirInlineAsm};
10 use crate::mir::interpret::{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, Debug, PartialEq, Eq, PartialOrd, Ord)]
82 /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
83 pub fn phase_index(&self) -> usize {
88 /// The lowered representation of a single function.
89 #[derive(Clone, RustcEncodable, RustcDecodable, Debug, TypeFoldable)]
90 pub struct Body<'tcx> {
91 /// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
92 /// that indexes into this vector.
93 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
95 /// Records how far through the "desugaring and optimization" process this particular
96 /// MIR has traversed. This is particularly useful when inlining, since in that context
97 /// we instantiate the promoted constants and add them to our promoted vector -- but those
98 /// promoted items have already been optimized, whereas ours have not. This field allows
99 /// us to see the difference and forego optimization on the inlined promoted items.
102 /// A list of source scopes; these are referenced by statements
103 /// and used for debuginfo. Indexed by a `SourceScope`.
104 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
106 /// Crate-local information for each source scope, that can't (and
107 /// needn't) be tracked across crates.
108 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
110 /// The yield type of the function, if it is a generator.
111 pub yield_ty: Option<Ty<'tcx>>,
113 /// Generator drop glue.
114 pub generator_drop: Option<Box<Body<'tcx>>>,
116 /// The layout of a generator. Produced by the state transformation.
117 pub generator_layout: Option<GeneratorLayout<'tcx>>,
119 /// Declarations of locals.
121 /// The first local is the return value pointer, followed by `arg_count`
122 /// locals for the function arguments, followed by any user-declared
123 /// variables and temporaries.
124 pub local_decls: LocalDecls<'tcx>,
126 /// User type annotations.
127 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
129 /// The number of arguments this function takes.
131 /// Starting at local 1, `arg_count` locals will be provided by the caller
132 /// and can be assumed to be initialized.
134 /// If this MIR was built for a constant, this will be 0.
135 pub arg_count: usize,
137 /// Mark an argument local (which must be a tuple) as getting passed as
138 /// its individual components at the LLVM level.
140 /// This is used for the "rust-call" ABI.
141 pub spread_arg: Option<Local>,
143 /// Names and capture modes of all the closure upvars, assuming
144 /// the first argument is either the closure or a reference to it.
146 // NOTE(eddyb) This is *strictly* a temporary hack for codegen
147 // debuginfo generation, and will be removed at some point.
148 // Do **NOT** use it for anything else; upvar information should not be
149 // in the MIR, so please rely on local crate HIR or other side-channels.
150 pub __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
152 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
153 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
154 /// this conversion from happening and use short circuiting, we will cause the following code
155 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
157 /// List of places where control flow was destroyed. Used for error reporting.
158 pub control_flow_destroyed: Vec<(Span, String)>,
160 /// A span representing this MIR, for error reporting.
163 /// A cache for various calculations.
167 impl<'tcx> Body<'tcx> {
169 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
170 source_scopes: IndexVec<SourceScope, SourceScopeData>,
171 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
172 yield_ty: Option<Ty<'tcx>>,
173 local_decls: LocalDecls<'tcx>,
174 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
176 __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
178 control_flow_destroyed: Vec<(Span, String)>,
180 // We need `arg_count` locals, and one for the return place.
182 local_decls.len() >= arg_count + 1,
183 "expected at least {} locals, got {}",
189 phase: MirPhase::Build,
192 source_scope_local_data,
194 generator_drop: None,
195 generator_layout: None,
197 user_type_annotations,
199 __upvar_debuginfo_codegen_only_do_not_use,
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].name.is_some() {
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.is_some() {
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.is_some() {
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.is_some() && 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.is_some() || 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_stable_hash_for!(struct Body<'tcx> {
419 source_scope_local_data,
424 user_type_annotations,
426 __upvar_debuginfo_codegen_only_do_not_use,
428 control_flow_destroyed,
433 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
434 type Output = BasicBlockData<'tcx>;
437 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
438 &self.basic_blocks()[index]
442 impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
444 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
445 &mut self.basic_blocks_mut()[index]
449 #[derive(Copy, Clone, Debug, HashStable, TypeFoldable)]
450 pub enum ClearCrossCrate<T> {
455 impl<T> ClearCrossCrate<T> {
456 pub fn assert_crate_local(self) -> T {
458 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
459 ClearCrossCrate::Set(v) => v,
464 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
465 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
467 /// Grouped information about the source code origin of a MIR entity.
468 /// Intended to be inspected by diagnostics and debuginfo.
469 /// Most passes can work with it as a whole, within a single function.
470 // The unoffical Cranelift backend, at least as of #65828, needs `SourceInfo` to implement `Eq` and
471 // `Hash`. Please ping @bjorn3 if removing them.
472 #[derive(Copy, Clone, Debug, Eq, PartialEq, RustcEncodable, RustcDecodable, Hash, HashStable)]
473 pub struct SourceInfo {
474 /// The source span for the AST pertaining to this MIR entity.
477 /// The source scope, keeping track of which bindings can be
478 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
479 pub scope: SourceScope,
482 ///////////////////////////////////////////////////////////////////////////
483 // Mutability and borrow kinds
485 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
486 pub enum Mutability {
491 impl From<Mutability> for hir::Mutability {
492 fn from(m: Mutability) -> Self {
494 Mutability::Mut => hir::Mutability::Mutable,
495 Mutability::Not => hir::Mutability::Immutable,
501 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
503 pub enum BorrowKind {
504 /// Data must be immutable and is aliasable.
507 /// The immediately borrowed place must be immutable, but projections from
508 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
509 /// conflict with a mutable borrow of `a.b.c`.
511 /// This is used when lowering matches: when matching on a place we want to
512 /// ensure that place have the same value from the start of the match until
513 /// an arm is selected. This prevents this code from compiling:
515 /// let mut x = &Some(0);
518 /// Some(_) if { x = &None; false } => (),
522 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
523 /// should not prevent `if let None = x { ... }`, for example, because the
524 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
525 /// We can also report errors with this kind of borrow differently.
528 /// Data must be immutable but not aliasable. This kind of borrow
529 /// cannot currently be expressed by the user and is used only in
530 /// implicit closure bindings. It is needed when the closure is
531 /// borrowing or mutating a mutable referent, e.g.:
533 /// let x: &mut isize = ...;
534 /// let y = || *x += 5;
536 /// If we were to try to translate this closure into a more explicit
537 /// form, we'd encounter an error with the code as written:
539 /// struct Env { x: & &mut isize }
540 /// let x: &mut isize = ...;
541 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
542 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
544 /// This is then illegal because you cannot mutate an `&mut` found
545 /// in an aliasable location. To solve, you'd have to translate with
546 /// an `&mut` borrow:
548 /// struct Env { x: & &mut isize }
549 /// let x: &mut isize = ...;
550 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
551 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
553 /// Now the assignment to `**env.x` is legal, but creating a
554 /// mutable pointer to `x` is not because `x` is not mutable. We
555 /// could fix this by declaring `x` as `let mut x`. This is ok in
556 /// user code, if awkward, but extra weird for closures, since the
557 /// borrow is hidden.
559 /// So we introduce a "unique imm" borrow -- the referent is
560 /// immutable, but not aliasable. This solves the problem. For
561 /// simplicity, we don't give users the way to express this
562 /// borrow, it's just used when translating closures.
565 /// Data is mutable and not aliasable.
567 /// `true` if this borrow arose from method-call auto-ref
568 /// (i.e., `adjustment::Adjust::Borrow`).
569 allow_two_phase_borrow: bool,
574 pub fn allows_two_phase_borrow(&self) -> bool {
576 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
577 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
582 ///////////////////////////////////////////////////////////////////////////
583 // Variables and temps
585 rustc_index::newtype_index! {
588 DEBUG_FORMAT = "_{}",
589 const RETURN_PLACE = 0,
593 impl Atom for Local {
594 fn index(self) -> usize {
599 /// Classifies locals into categories. See `Body::local_kind`.
600 #[derive(PartialEq, Eq, Debug, HashStable)]
602 /// User-declared variable binding.
604 /// Compiler-introduced temporary.
606 /// Function argument.
608 /// Location of function's return value.
612 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
613 pub struct VarBindingForm<'tcx> {
614 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
615 pub binding_mode: ty::BindingMode,
616 /// If an explicit type was provided for this variable binding,
617 /// this holds the source Span of that type.
619 /// NOTE: if you want to change this to a `HirId`, be wary that
620 /// doing so breaks incremental compilation (as of this writing),
621 /// while a `Span` does not cause our tests to fail.
622 pub opt_ty_info: Option<Span>,
623 /// Place of the RHS of the =, or the subject of the `match` where this
624 /// variable is initialized. None in the case of `let PATTERN;`.
625 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
626 /// (a) the right-hand side isn't evaluated as a place expression.
627 /// (b) it gives a way to separate this case from the remaining cases
629 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
630 /// The span of the pattern in which this variable was bound.
634 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
635 pub enum BindingForm<'tcx> {
636 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
637 Var(VarBindingForm<'tcx>),
638 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
639 ImplicitSelf(ImplicitSelfKind),
640 /// Reference used in a guard expression to ensure immutability.
644 /// Represents what type of implicit self a function has, if any.
645 #[derive(Clone, Copy, PartialEq, Debug, RustcEncodable, RustcDecodable)]
646 pub enum ImplicitSelfKind {
647 /// Represents a `fn x(self);`.
649 /// Represents a `fn x(mut self);`.
651 /// Represents a `fn x(&self);`.
653 /// Represents a `fn x(&mut self);`.
655 /// Represents when a function does not have a self argument or
656 /// when a function has a `self: X` argument.
660 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
662 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
669 impl_stable_hash_for!(enum self::ImplicitSelfKind {
677 impl_stable_hash_for!(enum self::MirPhase {
684 mod binding_form_impl {
685 use crate::ich::StableHashingContext;
686 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
688 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
689 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
690 use super::BindingForm::*;
691 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
694 Var(binding) => binding.hash_stable(hcx, hasher),
695 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
702 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
703 /// created during evaluation of expressions in a block tail
704 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
706 /// It is used to improve diagnostics when such temporaries are
707 /// involved in borrow_check errors, e.g., explanations of where the
708 /// temporaries come from, when their destructors are run, and/or how
709 /// one might revise the code to satisfy the borrow checker's rules.
710 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
711 pub struct BlockTailInfo {
712 /// If `true`, then the value resulting from evaluating this tail
713 /// expression is ignored by the block's expression context.
715 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
716 /// but not e.g., `let _x = { ...; tail };`
717 pub tail_result_is_ignored: bool,
720 impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
724 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
725 /// argument, or the return place.
726 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
727 pub struct LocalDecl<'tcx> {
728 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
730 /// Temporaries and the return place are always mutable.
731 pub mutability: Mutability,
733 /// `Some(binding_mode)` if this corresponds to a user-declared local variable.
735 /// This is solely used for local diagnostics when generating
736 /// warnings/errors when compiling the current crate, and
737 /// therefore it need not be visible across crates. pnkfelix
738 /// currently hypothesized we *need* to wrap this in a
739 /// `ClearCrossCrate` as long as it carries as `HirId`.
740 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
742 /// `true` if this is an internal local.
744 /// These locals are not based on types in the source code and are only used
745 /// for a few desugarings at the moment.
747 /// The generator transformation will sanity check the locals which are live
748 /// across a suspension point against the type components of the generator
749 /// which type checking knows are live across a suspension point. We need to
750 /// flag drop flags to avoid triggering this check as they are introduced
753 /// Unsafety checking will also ignore dereferences of these locals,
754 /// so they can be used for raw pointers only used in a desugaring.
756 /// This should be sound because the drop flags are fully algebraic, and
757 /// therefore don't affect the OIBIT or outlives properties of the
761 /// If this local is a temporary and `is_block_tail` is `Some`,
762 /// then it is a temporary created for evaluation of some
763 /// subexpression of some block's tail expression (with no
764 /// intervening statement context).
765 pub is_block_tail: Option<BlockTailInfo>,
767 /// The type of this local.
770 /// If the user manually ascribed a type to this variable,
771 /// e.g., via `let x: T`, then we carry that type here. The MIR
772 /// borrow checker needs this information since it can affect
773 /// region inference.
774 pub user_ty: UserTypeProjections,
776 /// The name of the local, used in debuginfo and pretty-printing.
778 /// Note that function arguments can also have this set to `Some(_)`
779 /// to generate better debuginfo.
780 pub name: Option<Name>,
782 /// The *syntactic* (i.e., not visibility) source scope the local is defined
783 /// in. If the local was defined in a let-statement, this
784 /// is *within* the let-statement, rather than outside
787 /// This is needed because the visibility source scope of locals within
788 /// a let-statement is weird.
790 /// The reason is that we want the local to be *within* the let-statement
791 /// for lint purposes, but we want the local to be *after* the let-statement
792 /// for names-in-scope purposes.
794 /// That's it, if we have a let-statement like the one in this
798 /// fn foo(x: &str) {
799 /// #[allow(unused_mut)]
800 /// let mut x: u32 = { // <- one unused mut
801 /// let mut y: u32 = x.parse().unwrap();
808 /// Then, from a lint point of view, the declaration of `x: u32`
809 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
810 /// lint scopes are the same as the AST/HIR nesting.
812 /// However, from a name lookup point of view, the scopes look more like
813 /// as if the let-statements were `match` expressions:
816 /// fn foo(x: &str) {
818 /// match x.parse().unwrap() {
827 /// We care about the name-lookup scopes for debuginfo - if the
828 /// debuginfo instruction pointer is at the call to `x.parse()`, we
829 /// want `x` to refer to `x: &str`, but if it is at the call to
830 /// `drop(x)`, we want it to refer to `x: u32`.
832 /// To allow both uses to work, we need to have more than a single scope
833 /// for a local. We have the `source_info.scope` represent the
834 /// "syntactic" lint scope (with a variable being under its let
835 /// block) while the `visibility_scope` represents the "local variable"
836 /// scope (where the "rest" of a block is under all prior let-statements).
838 /// The end result looks like this:
842 /// │{ argument x: &str }
844 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
845 /// │ │ // in practice because I'm lazy.
847 /// │ │← x.source_info.scope
848 /// │ │← `x.parse().unwrap()`
850 /// │ │ │← y.source_info.scope
852 /// │ │ │{ let y: u32 }
854 /// │ │ │← y.visibility_scope
857 /// │ │{ let x: u32 }
858 /// │ │← x.visibility_scope
859 /// │ │← `drop(x)` // This accesses `x: u32`.
861 pub source_info: SourceInfo,
863 /// Source scope within which the local is visible (for debuginfo)
864 /// (see `source_info` for more details).
865 pub visibility_scope: SourceScope,
868 impl<'tcx> LocalDecl<'tcx> {
869 /// Returns `true` only if local is a binding that can itself be
870 /// made mutable via the addition of the `mut` keyword, namely
871 /// something like the occurrences of `x` in:
872 /// - `fn foo(x: Type) { ... }`,
874 /// - or `match ... { C(x) => ... }`
875 pub fn can_be_made_mutable(&self) -> bool {
876 match self.is_user_variable {
877 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
878 binding_mode: ty::BindingMode::BindByValue(_),
884 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm))) => true,
890 /// Returns `true` if local is definitely not a `ref ident` or
891 /// `ref mut ident` binding. (Such bindings cannot be made into
892 /// mutable bindings, but the inverse does not necessarily hold).
893 pub fn is_nonref_binding(&self) -> bool {
894 match self.is_user_variable {
895 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
896 binding_mode: ty::BindingMode::BindByValue(_),
902 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
908 /// Returns `true` if this is a reference to a variable bound in a `match`
909 /// expression that is used to access said variable for the guard of the
911 pub fn is_ref_for_guard(&self) -> bool {
912 match self.is_user_variable {
913 Some(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
918 /// Returns `true` is the local is from a compiler desugaring, e.g.,
919 /// `__next` from a `for` loop.
921 pub fn from_compiler_desugaring(&self) -> bool {
922 self.source_info.span.desugaring_kind().is_some()
925 /// Creates a new `LocalDecl` for a temporary.
927 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
928 Self::new_local(ty, Mutability::Mut, false, span)
931 /// Converts `self` into same `LocalDecl` except tagged as immutable.
933 pub fn immutable(mut self) -> Self {
934 self.mutability = Mutability::Not;
938 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
940 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
941 assert!(self.is_block_tail.is_none());
942 self.is_block_tail = Some(info);
946 /// Creates a new `LocalDecl` for a internal temporary.
948 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
949 Self::new_local(ty, Mutability::Mut, true, span)
953 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
957 user_ty: UserTypeProjections::none(),
959 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
960 visibility_scope: OUTERMOST_SOURCE_SCOPE,
962 is_user_variable: None,
967 /// Builds a `LocalDecl` for the return place.
969 /// This must be inserted into the `local_decls` list as the first local.
971 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
973 mutability: Mutability::Mut,
975 user_ty: UserTypeProjections::none(),
976 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
977 visibility_scope: OUTERMOST_SOURCE_SCOPE,
980 name: None, // FIXME maybe we do want some name here?
981 is_user_variable: None,
986 /// A closure capture, with its name and mode.
987 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
988 pub struct UpvarDebuginfo {
989 pub debug_name: Name,
991 /// If true, the capture is behind a reference.
995 ///////////////////////////////////////////////////////////////////////////
998 rustc_index::newtype_index! {
999 pub struct BasicBlock {
1001 DEBUG_FORMAT = "bb{}",
1002 const START_BLOCK = 0,
1007 pub fn start_location(self) -> Location {
1008 Location { block: self, statement_index: 0 }
1012 ///////////////////////////////////////////////////////////////////////////
1013 // BasicBlockData and Terminator
1015 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1016 pub struct BasicBlockData<'tcx> {
1017 /// List of statements in this block.
1018 pub statements: Vec<Statement<'tcx>>,
1020 /// Terminator for this block.
1022 /// N.B., this should generally ONLY be `None` during construction.
1023 /// Therefore, you should generally access it via the
1024 /// `terminator()` or `terminator_mut()` methods. The only
1025 /// exception is that certain passes, such as `simplify_cfg`, swap
1026 /// out the terminator temporarily with `None` while they continue
1027 /// to recurse over the set of basic blocks.
1028 pub terminator: Option<Terminator<'tcx>>,
1030 /// If true, this block lies on an unwind path. This is used
1031 /// during codegen where distinct kinds of basic blocks may be
1032 /// generated (particularly for MSVC cleanup). Unwind blocks must
1033 /// only branch to other unwind blocks.
1034 pub is_cleanup: bool,
1037 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1038 pub struct Terminator<'tcx> {
1039 pub source_info: SourceInfo,
1040 pub kind: TerminatorKind<'tcx>,
1043 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1044 pub enum TerminatorKind<'tcx> {
1045 /// Block should have one successor in the graph; we jump there.
1046 Goto { target: BasicBlock },
1048 /// Operand evaluates to an integer; jump depending on its value
1049 /// to one of the targets, and otherwise fallback to `otherwise`.
1051 /// The discriminant value being tested.
1052 discr: Operand<'tcx>,
1054 /// The type of value being tested.
1055 switch_ty: Ty<'tcx>,
1057 /// Possible values. The locations to branch to in each case
1058 /// are found in the corresponding indices from the `targets` vector.
1059 values: Cow<'tcx, [u128]>,
1061 /// Possible branch sites. The last element of this vector is used
1062 /// for the otherwise branch, so targets.len() == values.len() + 1
1065 // This invariant is quite non-obvious and also could be improved.
1066 // One way to make this invariant is to have something like this instead:
1068 // branches: Vec<(ConstInt, BasicBlock)>,
1069 // otherwise: Option<BasicBlock> // exhaustive if None
1071 // However we’ve decided to keep this as-is until we figure a case
1072 // where some other approach seems to be strictly better than other.
1073 targets: Vec<BasicBlock>,
1076 /// Indicates that the landing pad is finished and unwinding should
1077 /// continue. Emitted by `build::scope::diverge_cleanup`.
1080 /// Indicates that the landing pad is finished and that the process
1081 /// should abort. Used to prevent unwinding for foreign items.
1084 /// Indicates a normal return. The return place should have
1085 /// been filled in by now. This should occur at most once.
1088 /// Indicates a terminator that can never be reached.
1091 /// Drop the `Place`.
1092 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1094 /// Drop the `Place` and assign the new value over it. This ensures
1095 /// that the assignment to `P` occurs *even if* the destructor for
1096 /// place unwinds. Its semantics are best explained by the
1101 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1109 /// Drop(P, goto BB1, unwind BB2)
1112 /// // P is now uninitialized
1116 /// // P is now uninitialized -- its dtor panicked
1121 location: Place<'tcx>,
1122 value: Operand<'tcx>,
1124 unwind: Option<BasicBlock>,
1127 /// Block ends with a call of a converging function.
1129 /// The function that’s being called.
1130 func: Operand<'tcx>,
1131 /// Arguments the function is called with.
1132 /// These are owned by the callee, which is free to modify them.
1133 /// This allows the memory occupied by "by-value" arguments to be
1134 /// reused across function calls without duplicating the contents.
1135 args: Vec<Operand<'tcx>>,
1136 /// Destination for the return value. If some, the call is converging.
1137 destination: Option<(Place<'tcx>, BasicBlock)>,
1138 /// Cleanups to be done if the call unwinds.
1139 cleanup: Option<BasicBlock>,
1140 /// `true` if this is from a call in HIR rather than from an overloaded
1141 /// operator. True for overloaded function call.
1142 from_hir_call: bool,
1145 /// Jump to the target if the condition has the expected value,
1146 /// otherwise panic with a message and a cleanup target.
1148 cond: Operand<'tcx>,
1150 msg: AssertMessage<'tcx>,
1152 cleanup: Option<BasicBlock>,
1155 /// A suspend point.
1157 /// The value to return.
1158 value: Operand<'tcx>,
1159 /// Where to resume to.
1161 /// Cleanup to be done if the generator is dropped at this suspend point.
1162 drop: Option<BasicBlock>,
1165 /// Indicates the end of the dropping of a generator.
1168 /// A block where control flow only ever takes one real path, but borrowck
1169 /// needs to be more conservative.
1171 /// The target normal control flow will take.
1172 real_target: BasicBlock,
1173 /// A block control flow could conceptually jump to, but won't in
1175 imaginary_target: BasicBlock,
1177 /// A terminator for blocks that only take one path in reality, but where we
1178 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1179 /// This can arise in infinite loops with no function calls for example.
1181 /// The target normal control flow will take.
1182 real_target: BasicBlock,
1183 /// The imaginary cleanup block link. This particular path will never be taken
1184 /// in practice, but in order to avoid fragility we want to always
1185 /// consider it in borrowck. We don't want to accept programs which
1186 /// pass borrowck only when `panic=abort` or some assertions are disabled
1187 /// due to release vs. debug mode builds. This needs to be an `Option` because
1188 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1189 unwind: Option<BasicBlock>,
1193 pub type Successors<'a> =
1194 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1195 pub type SuccessorsMut<'a> =
1196 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1198 impl<'tcx> Terminator<'tcx> {
1199 pub fn successors(&self) -> Successors<'_> {
1200 self.kind.successors()
1203 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1204 self.kind.successors_mut()
1207 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1211 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1212 self.kind.unwind_mut()
1216 impl<'tcx> TerminatorKind<'tcx> {
1219 cond: Operand<'tcx>,
1222 ) -> TerminatorKind<'tcx> {
1223 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1224 TerminatorKind::SwitchInt {
1226 switch_ty: tcx.types.bool,
1227 values: From::from(BOOL_SWITCH_FALSE),
1228 targets: vec![f, t],
1232 pub fn successors(&self) -> Successors<'_> {
1233 use self::TerminatorKind::*;
1240 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1241 Goto { target: ref t }
1242 | Call { destination: None, cleanup: Some(ref t), .. }
1243 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1244 | Yield { resume: ref t, drop: None, .. }
1245 | DropAndReplace { target: ref t, unwind: None, .. }
1246 | Drop { target: ref t, unwind: None, .. }
1247 | Assert { target: ref t, cleanup: None, .. }
1248 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1249 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1250 | Yield { resume: ref t, drop: Some(ref u), .. }
1251 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1252 | Drop { target: ref t, unwind: Some(ref u), .. }
1253 | Assert { target: ref t, cleanup: Some(ref u), .. }
1254 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1255 Some(t).into_iter().chain(slice::from_ref(u))
1257 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1258 FalseEdges { ref real_target, ref imaginary_target } => {
1259 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1264 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1265 use self::TerminatorKind::*;
1272 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1273 Goto { target: ref mut t }
1274 | Call { destination: None, cleanup: Some(ref mut t), .. }
1275 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1276 | Yield { resume: ref mut t, drop: None, .. }
1277 | DropAndReplace { target: ref mut t, unwind: None, .. }
1278 | Drop { target: ref mut t, unwind: None, .. }
1279 | Assert { target: ref mut t, cleanup: None, .. }
1280 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1281 Some(t).into_iter().chain(&mut [])
1283 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1284 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1285 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1286 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1287 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1288 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1289 Some(t).into_iter().chain(slice::from_mut(u))
1291 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1292 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1293 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1298 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1300 TerminatorKind::Goto { .. }
1301 | TerminatorKind::Resume
1302 | TerminatorKind::Abort
1303 | TerminatorKind::Return
1304 | TerminatorKind::Unreachable
1305 | TerminatorKind::GeneratorDrop
1306 | TerminatorKind::Yield { .. }
1307 | TerminatorKind::SwitchInt { .. }
1308 | TerminatorKind::FalseEdges { .. } => None,
1309 TerminatorKind::Call { cleanup: ref unwind, .. }
1310 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1311 | TerminatorKind::DropAndReplace { ref unwind, .. }
1312 | TerminatorKind::Drop { ref unwind, .. }
1313 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1317 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1319 TerminatorKind::Goto { .. }
1320 | TerminatorKind::Resume
1321 | TerminatorKind::Abort
1322 | TerminatorKind::Return
1323 | TerminatorKind::Unreachable
1324 | TerminatorKind::GeneratorDrop
1325 | TerminatorKind::Yield { .. }
1326 | TerminatorKind::SwitchInt { .. }
1327 | TerminatorKind::FalseEdges { .. } => None,
1328 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1329 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1330 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1331 | TerminatorKind::Drop { ref mut unwind, .. }
1332 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1337 impl<'tcx> BasicBlockData<'tcx> {
1338 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1339 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1342 /// Accessor for terminator.
1344 /// Terminator may not be None after construction of the basic block is complete. This accessor
1345 /// provides a convenience way to reach the terminator.
1346 pub fn terminator(&self) -> &Terminator<'tcx> {
1347 self.terminator.as_ref().expect("invalid terminator state")
1350 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1351 self.terminator.as_mut().expect("invalid terminator state")
1354 pub fn retain_statements<F>(&mut self, mut f: F)
1356 F: FnMut(&mut Statement<'_>) -> bool,
1358 for s in &mut self.statements {
1365 pub fn expand_statements<F, I>(&mut self, mut f: F)
1367 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1368 I: iter::TrustedLen<Item = Statement<'tcx>>,
1370 // Gather all the iterators we'll need to splice in, and their positions.
1371 let mut splices: Vec<(usize, I)> = vec![];
1372 let mut extra_stmts = 0;
1373 for (i, s) in self.statements.iter_mut().enumerate() {
1374 if let Some(mut new_stmts) = f(s) {
1375 if let Some(first) = new_stmts.next() {
1376 // We can already store the first new statement.
1379 // Save the other statements for optimized splicing.
1380 let remaining = new_stmts.size_hint().0;
1382 splices.push((i + 1 + extra_stmts, new_stmts));
1383 extra_stmts += remaining;
1391 // Splice in the new statements, from the end of the block.
1392 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1393 // where a range of elements ("gap") is left uninitialized, with
1394 // splicing adding new elements to the end of that gap and moving
1395 // existing elements from before the gap to the end of the gap.
1396 // For now, this is safe code, emulating a gap but initializing it.
1397 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1398 self.statements.resize(
1401 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1402 kind: StatementKind::Nop,
1405 for (splice_start, new_stmts) in splices.into_iter().rev() {
1406 let splice_end = splice_start + new_stmts.size_hint().0;
1407 while gap.end > splice_end {
1410 self.statements.swap(gap.start, gap.end);
1412 self.statements.splice(splice_start..splice_end, new_stmts);
1413 gap.end = splice_start;
1417 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1418 if index < self.statements.len() {
1419 &self.statements[index]
1426 impl<'tcx> Debug for TerminatorKind<'tcx> {
1427 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1428 self.fmt_head(fmt)?;
1429 let successor_count = self.successors().count();
1430 let labels = self.fmt_successor_labels();
1431 assert_eq!(successor_count, labels.len());
1433 match successor_count {
1436 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1439 write!(fmt, " -> [")?;
1440 for (i, target) in self.successors().enumerate() {
1444 write!(fmt, "{}: {:?}", labels[i], target)?;
1452 impl<'tcx> TerminatorKind<'tcx> {
1453 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1454 /// successor basic block, if any. The only information not included is the list of possible
1455 /// successors, which may be rendered differently between the text and the graphviz format.
1456 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1457 use self::TerminatorKind::*;
1459 Goto { .. } => write!(fmt, "goto"),
1460 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1461 Return => write!(fmt, "return"),
1462 GeneratorDrop => write!(fmt, "generator_drop"),
1463 Resume => write!(fmt, "resume"),
1464 Abort => write!(fmt, "abort"),
1465 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1466 Unreachable => write!(fmt, "unreachable"),
1467 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1468 DropAndReplace { ref location, ref value, .. } => {
1469 write!(fmt, "replace({:?} <- {:?})", location, value)
1471 Call { ref func, ref args, ref destination, .. } => {
1472 if let Some((ref destination, _)) = *destination {
1473 write!(fmt, "{:?} = ", destination)?;
1475 write!(fmt, "{:?}(", func)?;
1476 for (index, arg) in args.iter().enumerate() {
1480 write!(fmt, "{:?}", arg)?;
1484 Assert { ref cond, expected, ref msg, .. } => {
1485 write!(fmt, "assert(")?;
1489 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1491 FalseEdges { .. } => write!(fmt, "falseEdges"),
1492 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1496 /// Returns the list of labels for the edges to the successor basic blocks.
1497 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1498 use self::TerminatorKind::*;
1500 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1501 Goto { .. } => vec!["".into()],
1502 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1503 let param_env = ty::ParamEnv::empty();
1504 let switch_ty = tcx.lift(&switch_ty).unwrap();
1505 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1509 ty::Const::from_scalar(
1511 Scalar::from_uint(u, size).into(),
1517 .chain(iter::once("otherwise".into()))
1520 Call { destination: Some(_), cleanup: Some(_), .. } => {
1521 vec!["return".into(), "unwind".into()]
1523 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1524 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1525 Call { destination: None, cleanup: None, .. } => vec![],
1526 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1527 Yield { drop: None, .. } => vec!["resume".into()],
1528 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1529 vec!["return".into()]
1531 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1532 vec!["return".into(), "unwind".into()]
1534 Assert { cleanup: None, .. } => vec!["".into()],
1535 Assert { .. } => vec!["success".into(), "unwind".into()],
1536 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1537 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1538 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1543 ///////////////////////////////////////////////////////////////////////////
1546 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1547 pub struct Statement<'tcx> {
1548 pub source_info: SourceInfo,
1549 pub kind: StatementKind<'tcx>,
1552 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1553 #[cfg(target_arch = "x86_64")]
1554 static_assert_size!(Statement<'_>, 32);
1556 impl Statement<'_> {
1557 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1558 /// invalidating statement indices in `Location`s.
1559 pub fn make_nop(&mut self) {
1560 self.kind = StatementKind::Nop
1563 /// Changes a statement to a nop and returns the original statement.
1564 pub fn replace_nop(&mut self) -> Self {
1566 source_info: self.source_info,
1567 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1572 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1573 pub enum StatementKind<'tcx> {
1574 /// Write the RHS Rvalue to the LHS Place.
1575 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1577 /// This represents all the reading that a pattern match may do
1578 /// (e.g., inspecting constants and discriminant values), and the
1579 /// kind of pattern it comes from. This is in order to adapt potential
1580 /// error messages to these specific patterns.
1582 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1583 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1584 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1586 /// Write the discriminant for a variant to the enum Place.
1587 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1589 /// Start a live range for the storage of the local.
1592 /// End the current live range for the storage of the local.
1595 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1596 /// of `StatementKind` low.
1597 InlineAsm(Box<InlineAsm<'tcx>>),
1599 /// Retag references in the given place, ensuring they got fresh tags. This is
1600 /// part of the Stacked Borrows model. These statements are currently only interpreted
1601 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1602 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1603 /// for more details.
1604 Retag(RetagKind, Box<Place<'tcx>>),
1606 /// Encodes a user's type ascription. These need to be preserved
1607 /// intact so that NLL can respect them. For example:
1611 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1612 /// to the user-given type `T`. The effect depends on the specified variance:
1614 /// - `Covariant` -- requires that `T_y <: T`
1615 /// - `Contravariant` -- requires that `T_y :> T`
1616 /// - `Invariant` -- requires that `T_y == T`
1617 /// - `Bivariant` -- no effect
1618 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1620 /// No-op. Useful for deleting instructions without affecting statement indices.
1624 /// Describes what kind of retag is to be performed.
1625 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1626 pub enum RetagKind {
1627 /// The initial retag when entering a function.
1629 /// Retag preparing for a two-phase borrow.
1631 /// Retagging raw pointers.
1633 /// A "normal" retag.
1637 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1638 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
1639 pub enum FakeReadCause {
1640 /// Inject a fake read of the borrowed input at the end of each guards
1643 /// This should ensure that you cannot change the variant for an enum while
1644 /// you are in the midst of matching on it.
1647 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1648 /// generate a read of x to check that it is initialized and safe.
1651 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1652 /// in a match guard to ensure that it's value hasn't change by the time
1653 /// we create the OutsideGuard version.
1656 /// Officially, the semantics of
1658 /// `let pattern = <expr>;`
1660 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1661 /// into the pattern.
1663 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1664 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1665 /// but in some cases it can affect the borrow checker, as in #53695.
1666 /// Therefore, we insert a "fake read" here to ensure that we get
1667 /// appropriate errors.
1670 /// If we have an index expression like
1672 /// (*x)[1][{ x = y; 4}]
1674 /// then the first bounds check is invalidated when we evaluate the second
1675 /// index expression. Thus we create a fake borrow of `x` across the second
1676 /// indexer, which will cause a borrow check error.
1680 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
1681 pub struct InlineAsm<'tcx> {
1682 pub asm: HirInlineAsm,
1683 pub outputs: Box<[Place<'tcx>]>,
1684 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1687 impl Debug for Statement<'_> {
1688 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1689 use self::StatementKind::*;
1691 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1692 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1693 Retag(ref kind, ref place) => write!(
1697 RetagKind::FnEntry => "[fn entry] ",
1698 RetagKind::TwoPhase => "[2phase] ",
1699 RetagKind::Raw => "[raw] ",
1700 RetagKind::Default => "",
1704 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1705 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1706 SetDiscriminant { ref place, variant_index } => {
1707 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1709 InlineAsm(ref asm) => {
1710 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1712 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1713 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1715 Nop => write!(fmt, "nop"),
1720 ///////////////////////////////////////////////////////////////////////////
1723 /// A path to a value; something that can be evaluated without
1724 /// changing or disturbing program state.
1726 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, HashStable,
1728 pub struct Place<'tcx> {
1729 pub base: PlaceBase<'tcx>,
1731 /// projection out of a place (access a field, deref a pointer, etc)
1732 pub projection: &'tcx List<PlaceElem<'tcx>>,
1735 impl<'tcx> rustc_serialize::UseSpecializedDecodable for Place<'tcx> {}
1738 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1740 pub enum PlaceBase<'tcx> {
1744 /// static or static mut variable
1745 Static(Box<Static<'tcx>>),
1748 /// We store the normalized type to avoid requiring normalization when reading MIR
1749 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
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 impl_stable_hash_for!(struct Static<'tcx> {
1777 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1778 #[derive(RustcEncodable, RustcDecodable, HashStable)]
1779 pub enum ProjectionElem<V, T> {
1784 /// These indices are generated by slice patterns. Easiest to explain
1788 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1789 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1790 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1791 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1794 /// index or -index (in Python terms), depending on from_end
1796 /// thing being indexed must be at least this long
1798 /// counting backwards from end?
1802 /// These indices are generated by slice patterns.
1804 /// slice[from:-to] in Python terms.
1810 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1811 /// this for ADTs with more than one variant. It may be better to
1812 /// just introduce it always, or always for enums.
1814 /// The included Symbol is the name of the variant, used for printing MIR.
1815 Downcast(Option<Symbol>, VariantIdx),
1818 impl<V, T> ProjectionElem<V, T> {
1819 /// Returns `true` if the target of this projection may refer to a different region of memory
1821 fn is_indirect(&self) -> bool {
1823 Self::Deref => true,
1827 | Self::ConstantIndex { .. }
1828 | Self::Subslice { .. }
1829 | Self::Downcast(_, _)
1835 /// Alias for projections as they appear in places, where the base is a place
1836 /// and the index is a local.
1837 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1839 impl<'tcx> Copy for PlaceElem<'tcx> { }
1841 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1842 #[cfg(target_arch = "x86_64")]
1843 static_assert_size!(PlaceElem<'_>, 16);
1845 /// Alias for projections as they appear in `UserTypeProjection`, where we
1846 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1847 pub type ProjectionKind = ProjectionElem<(), ()>;
1849 rustc_index::newtype_index! {
1852 DEBUG_FORMAT = "field[{}]"
1856 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1857 pub struct PlaceRef<'a, 'tcx> {
1858 pub base: &'a PlaceBase<'tcx>,
1859 pub projection: &'a [PlaceElem<'tcx>],
1862 impl<'tcx> Place<'tcx> {
1863 // FIXME change this to a const fn by also making List::empty a const fn.
1864 pub fn return_place() -> Place<'tcx> {
1866 base: PlaceBase::Local(RETURN_PLACE),
1867 projection: List::empty(),
1871 /// Returns `true` if this `Place` contains a `Deref` projection.
1873 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1874 /// same region of memory as its base.
1875 pub fn is_indirect(&self) -> bool {
1876 self.projection.iter().any(|elem| elem.is_indirect())
1879 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1880 /// a single deref of a local.
1882 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1883 pub fn local_or_deref_local(&self) -> Option<Local> {
1884 match self.as_ref() {
1886 base: &PlaceBase::Local(local),
1890 base: &PlaceBase::Local(local),
1891 projection: &[ProjectionElem::Deref],
1897 /// If this place represents a local variable like `_X` with no
1898 /// projections, return `Some(_X)`.
1899 pub fn as_local(&self) -> Option<Local> {
1900 self.as_ref().as_local()
1903 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1906 projection: &self.projection,
1911 impl From<Local> for Place<'_> {
1912 fn from(local: Local) -> Self {
1915 projection: List::empty(),
1920 impl From<Local> for PlaceBase<'_> {
1921 fn from(local: Local) -> Self {
1922 PlaceBase::Local(local)
1926 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1927 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1928 /// a single deref of a local.
1930 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1931 pub fn local_or_deref_local(&self) -> Option<Local> {
1934 base: PlaceBase::Local(local),
1938 base: PlaceBase::Local(local),
1939 projection: [ProjectionElem::Deref],
1945 /// If this place represents a local variable like `_X` with no
1946 /// projections, return `Some(_X)`.
1947 pub fn as_local(&self) -> Option<Local> {
1949 PlaceRef { base: PlaceBase::Local(l), projection: [] } => Some(*l),
1955 impl Debug for Place<'_> {
1956 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1957 for elem in self.projection.iter().rev() {
1959 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1960 write!(fmt, "(").unwrap();
1962 ProjectionElem::Deref => {
1963 write!(fmt, "(*").unwrap();
1965 ProjectionElem::Index(_)
1966 | ProjectionElem::ConstantIndex { .. }
1967 | ProjectionElem::Subslice { .. } => {}
1971 write!(fmt, "{:?}", self.base)?;
1973 for elem in self.projection.iter() {
1975 ProjectionElem::Downcast(Some(name), _index) => {
1976 write!(fmt, " as {})", name)?;
1978 ProjectionElem::Downcast(None, index) => {
1979 write!(fmt, " as variant#{:?})", index)?;
1981 ProjectionElem::Deref => {
1984 ProjectionElem::Field(field, ty) => {
1985 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
1987 ProjectionElem::Index(ref index) => {
1988 write!(fmt, "[{:?}]", index)?;
1990 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
1991 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
1993 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
1994 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
1996 ProjectionElem::Subslice { from, to } if *to == 0 => {
1997 write!(fmt, "[{:?}:]", from)?;
1999 ProjectionElem::Subslice { from, to } if *from == 0 => {
2000 write!(fmt, "[:-{:?}]", to)?;
2002 ProjectionElem::Subslice { from, to } => {
2003 write!(fmt, "[{:?}:-{:?}]", from, to)?;
2012 impl Debug for PlaceBase<'_> {
2013 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2015 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
2016 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
2017 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
2019 PlaceBase::Static(box self::Static {
2020 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
2022 write!(fmt, "({:?}: {:?})", promoted, ty)
2028 ///////////////////////////////////////////////////////////////////////////
2031 rustc_index::newtype_index! {
2032 pub struct SourceScope {
2034 DEBUG_FORMAT = "scope[{}]",
2035 const OUTERMOST_SOURCE_SCOPE = 0,
2039 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2040 pub struct SourceScopeData {
2042 pub parent_scope: Option<SourceScope>,
2045 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2046 pub struct SourceScopeLocalData {
2047 /// An `HirId` with lint levels equivalent to this scope's lint levels.
2048 pub lint_root: hir::HirId,
2049 /// The unsafe block that contains this node.
2053 ///////////////////////////////////////////////////////////////////////////
2056 /// These are values that can appear inside an rvalue. They are intentionally
2057 /// limited to prevent rvalues from being nested in one another.
2058 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2059 pub enum Operand<'tcx> {
2060 /// Copy: The value must be available for use afterwards.
2062 /// This implies that the type of the place must be `Copy`; this is true
2063 /// by construction during build, but also checked by the MIR type checker.
2066 /// Move: The value (including old borrows of it) will not be used again.
2068 /// Safe for values of all types (modulo future developments towards `?Move`).
2069 /// Correct usage patterns are enforced by the borrow checker for safe code.
2070 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2073 /// Synthesizes a constant value.
2074 Constant(Box<Constant<'tcx>>),
2077 impl<'tcx> Debug for Operand<'tcx> {
2078 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2079 use self::Operand::*;
2081 Constant(ref a) => write!(fmt, "{:?}", a),
2082 Copy(ref place) => write!(fmt, "{:?}", place),
2083 Move(ref place) => write!(fmt, "move {:?}", place),
2088 impl<'tcx> Operand<'tcx> {
2089 /// Convenience helper to make a constant that refers to the fn
2090 /// with given `DefId` and substs. Since this is used to synthesize
2091 /// MIR, assumes `user_ty` is None.
2092 pub fn function_handle(
2095 substs: SubstsRef<'tcx>,
2098 let ty = tcx.type_of(def_id).subst(tcx, substs);
2099 Operand::Constant(box Constant {
2102 literal: ty::Const::zero_sized(tcx, ty),
2106 pub fn to_copy(&self) -> Self {
2108 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2109 Operand::Move(ref place) => Operand::Copy(place.clone()),
2114 ///////////////////////////////////////////////////////////////////////////
2117 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2118 pub enum Rvalue<'tcx> {
2119 /// x (either a move or copy, depending on type of x)
2123 Repeat(Operand<'tcx>, u64),
2126 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2128 /// length of a [X] or [X;n] value
2131 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2133 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2134 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2136 NullaryOp(NullOp, Ty<'tcx>),
2137 UnaryOp(UnOp, Operand<'tcx>),
2139 /// Read the discriminant of an ADT.
2141 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2142 /// be defined to return, say, a 0) if ADT is not an enum.
2143 Discriminant(Place<'tcx>),
2145 /// Creates an aggregate value, like a tuple or struct. This is
2146 /// only needed because we want to distinguish `dest = Foo { x:
2147 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2148 /// that `Foo` has a destructor. These rvalues can be optimized
2149 /// away after type-checking and before lowering.
2150 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2153 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2156 Pointer(PointerCast),
2159 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2160 pub enum AggregateKind<'tcx> {
2161 /// The type is of the element
2165 /// The second field is the variant index. It's equal to 0 for struct
2166 /// and union expressions. The fourth field is
2167 /// active field number and is present only for union expressions
2168 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2169 /// active field index would identity the field `c`
2170 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2172 Closure(DefId, SubstsRef<'tcx>),
2173 Generator(DefId, SubstsRef<'tcx>, hir::Movability),
2176 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2178 /// The `+` operator (addition)
2180 /// The `-` operator (subtraction)
2182 /// The `*` operator (multiplication)
2184 /// The `/` operator (division)
2186 /// The `%` operator (modulus)
2188 /// The `^` operator (bitwise xor)
2190 /// The `&` operator (bitwise and)
2192 /// The `|` operator (bitwise or)
2194 /// The `<<` operator (shift left)
2196 /// The `>>` operator (shift right)
2198 /// The `==` operator (equality)
2200 /// The `<` operator (less than)
2202 /// The `<=` operator (less than or equal to)
2204 /// The `!=` operator (not equal to)
2206 /// The `>=` operator (greater than or equal to)
2208 /// The `>` operator (greater than)
2210 /// The `ptr.offset` operator
2215 pub fn is_checkable(self) -> bool {
2218 Add | Sub | Mul | Shl | Shr => true,
2224 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2226 /// Returns the size of a value of that type
2228 /// Creates a new uninitialized box for a value of that type
2232 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2234 /// The `!` operator for logical inversion
2236 /// The `-` operator for negation
2240 impl<'tcx> Debug for Rvalue<'tcx> {
2241 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2242 use self::Rvalue::*;
2245 Use(ref place) => write!(fmt, "{:?}", place),
2246 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2247 Len(ref a) => write!(fmt, "Len({:?})", a),
2248 Cast(ref kind, ref place, ref ty) => {
2249 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2251 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2252 CheckedBinaryOp(ref op, ref a, ref b) => {
2253 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2255 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2256 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2257 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2258 Ref(region, borrow_kind, ref place) => {
2259 let kind_str = match borrow_kind {
2260 BorrowKind::Shared => "",
2261 BorrowKind::Shallow => "shallow ",
2262 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2265 // When printing regions, add trailing space if necessary.
2266 let print_region = ty::tls::with(|tcx| {
2267 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2269 let region = if print_region {
2270 let mut region = region.to_string();
2271 if region.len() > 0 {
2276 // Do not even print 'static
2279 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2282 Aggregate(ref kind, ref places) => {
2283 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2284 let mut tuple_fmt = fmt.debug_tuple("");
2285 for place in places {
2286 tuple_fmt.field(place);
2292 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2294 AggregateKind::Tuple => match places.len() {
2295 0 => write!(fmt, "()"),
2296 1 => write!(fmt, "({:?},)", places[0]),
2297 _ => fmt_tuple(fmt, places),
2300 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2301 let variant_def = &adt_def.variants[variant];
2304 ty::tls::with(|tcx| {
2305 let substs = tcx.lift(&substs).expect("could not lift for printing");
2306 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2307 .print_def_path(variant_def.def_id, substs)?;
2311 match variant_def.ctor_kind {
2312 CtorKind::Const => Ok(()),
2313 CtorKind::Fn => fmt_tuple(fmt, places),
2314 CtorKind::Fictive => {
2315 let mut struct_fmt = fmt.debug_struct("");
2316 for (field, place) in variant_def.fields.iter().zip(places) {
2317 struct_fmt.field(&field.ident.as_str(), place);
2324 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2325 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2326 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2327 format!("[closure@{:?}]", hir_id)
2329 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2331 let mut struct_fmt = fmt.debug_struct(&name);
2333 if let Some(upvars) = tcx.upvars(def_id) {
2334 for (&var_id, place) in upvars.keys().zip(places) {
2335 let var_name = tcx.hir().name(var_id);
2336 struct_fmt.field(&var_name.as_str(), place);
2342 write!(fmt, "[closure]")
2346 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2347 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2348 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2349 let mut struct_fmt = fmt.debug_struct(&name);
2351 if let Some(upvars) = tcx.upvars(def_id) {
2352 for (&var_id, place) in upvars.keys().zip(places) {
2353 let var_name = tcx.hir().name(var_id);
2354 struct_fmt.field(&var_name.as_str(), place);
2360 write!(fmt, "[generator]")
2369 ///////////////////////////////////////////////////////////////////////////
2372 /// Two constants are equal if they are the same constant. Note that
2373 /// this does not necessarily mean that they are "==" in Rust -- in
2374 /// particular one must be wary of `NaN`!
2376 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2377 pub struct Constant<'tcx> {
2380 /// Optional user-given type: for something like
2381 /// `collect::<Vec<_>>`, this would be present and would
2382 /// indicate that `Vec<_>` was explicitly specified.
2384 /// Needed for NLL to impose user-given type constraints.
2385 pub user_ty: Option<UserTypeAnnotationIndex>,
2387 pub literal: &'tcx ty::Const<'tcx>,
2390 /// A collection of projections into user types.
2392 /// They are projections because a binding can occur a part of a
2393 /// parent pattern that has been ascribed a type.
2395 /// Its a collection because there can be multiple type ascriptions on
2396 /// the path from the root of the pattern down to the binding itself.
2401 /// struct S<'a>((i32, &'a str), String);
2402 /// let S((_, w): (i32, &'static str), _): S = ...;
2403 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2404 /// // --------------------------------- ^ (2)
2407 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2408 /// ascribed the type `(i32, &'static str)`.
2410 /// The highlights labelled `(2)` show the whole pattern being
2411 /// ascribed the type `S`.
2413 /// In this example, when we descend to `w`, we will have built up the
2414 /// following two projected types:
2416 /// * base: `S`, projection: `(base.0).1`
2417 /// * base: `(i32, &'static str)`, projection: `base.1`
2419 /// The first will lead to the constraint `w: &'1 str` (for some
2420 /// inferred region `'1`). The second will lead to the constraint `w:
2422 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2423 pub struct UserTypeProjections {
2424 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2427 impl<'tcx> UserTypeProjections {
2428 pub fn none() -> Self {
2429 UserTypeProjections { contents: vec![] }
2432 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2433 UserTypeProjections { contents: projs.collect() }
2436 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2437 self.contents.iter()
2440 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2441 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2444 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2445 self.contents.push((user_ty.clone(), span));
2451 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2453 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2457 pub fn index(self) -> Self {
2458 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2461 pub fn subslice(self, from: u32, to: u32) -> Self {
2462 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2465 pub fn deref(self) -> Self {
2466 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2469 pub fn leaf(self, field: Field) -> Self {
2470 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2473 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2474 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2478 /// Encodes the effect of a user-supplied type annotation on the
2479 /// subcomponents of a pattern. The effect is determined by applying the
2480 /// given list of proejctions to some underlying base type. Often,
2481 /// the projection element list `projs` is empty, in which case this
2482 /// directly encodes a type in `base`. But in the case of complex patterns with
2483 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2484 /// in which case the `projs` vector is used.
2488 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2490 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2491 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2492 /// determined by finding the type of the `.0` field from `T`.
2493 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2494 pub struct UserTypeProjection {
2495 pub base: UserTypeAnnotationIndex,
2496 pub projs: Vec<ProjectionKind>,
2499 impl Copy for ProjectionKind {}
2501 impl UserTypeProjection {
2502 pub(crate) fn index(mut self) -> Self {
2503 self.projs.push(ProjectionElem::Index(()));
2507 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2508 self.projs.push(ProjectionElem::Subslice { from, to });
2512 pub(crate) fn deref(mut self) -> Self {
2513 self.projs.push(ProjectionElem::Deref);
2517 pub(crate) fn leaf(mut self, field: Field) -> Self {
2518 self.projs.push(ProjectionElem::Field(field, ()));
2522 pub(crate) fn variant(
2524 adt_def: &'tcx AdtDef,
2525 variant_index: VariantIdx,
2528 self.projs.push(ProjectionElem::Downcast(
2529 Some(adt_def.variants[variant_index].ident.name),
2532 self.projs.push(ProjectionElem::Field(field, ()));
2537 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2539 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2540 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2541 use crate::mir::ProjectionElem::*;
2543 let base = self.base.fold_with(folder);
2544 let projs: Vec<_> = self
2547 .map(|elem| match elem {
2549 Field(f, ()) => Field(f.clone(), ()),
2550 Index(()) => Index(()),
2551 elem => elem.clone(),
2555 UserTypeProjection { base, projs }
2558 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2559 self.base.visit_with(visitor)
2560 // Note: there's nothing in `self.proj` to visit.
2564 rustc_index::newtype_index! {
2565 pub struct Promoted {
2567 DEBUG_FORMAT = "promoted[{}]"
2571 impl<'tcx> Debug for Constant<'tcx> {
2572 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2573 write!(fmt, "{}", self)
2577 impl<'tcx> Display for Constant<'tcx> {
2578 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2579 write!(fmt, "const ")?;
2580 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2581 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2582 // detailed and just not '{pointer}'.
2583 if let ty::RawPtr(_) = self.literal.ty.kind {
2584 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2586 write!(fmt, "{}", self.literal)
2591 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2592 type Node = BasicBlock;
2595 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2596 fn num_nodes(&self) -> usize {
2597 self.basic_blocks.len()
2601 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2602 fn start_node(&self) -> Self::Node {
2607 impl<'tcx> graph::WithPredecessors for Body<'tcx> {
2611 ) -> <Self as GraphPredecessors<'_>>::Iter {
2612 self.predecessors_for(node).clone().into_iter()
2616 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2620 ) -> <Self as GraphSuccessors<'_>>::Iter {
2621 self.basic_blocks[node].terminator().successors().cloned()
2625 impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
2626 type Item = BasicBlock;
2627 type Iter = IntoIter<BasicBlock>;
2630 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2631 type Item = BasicBlock;
2632 type Iter = iter::Cloned<Successors<'b>>;
2635 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2636 pub struct Location {
2637 /// The block that the location is within.
2638 pub block: BasicBlock,
2640 /// The location is the position of the start of the statement; or, if
2641 /// `statement_index` equals the number of statements, then the start of the
2643 pub statement_index: usize,
2646 impl fmt::Debug for Location {
2647 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2648 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2653 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2655 /// Returns the location immediately after this one within the enclosing block.
2657 /// Note that if this location represents a terminator, then the
2658 /// resulting location would be out of bounds and invalid.
2659 pub fn successor_within_block(&self) -> Location {
2660 Location { block: self.block, statement_index: self.statement_index + 1 }
2663 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2664 pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
2665 // If we are in the same block as the other location and are an earlier statement
2666 // then we are a predecessor of `other`.
2667 if self.block == other.block && self.statement_index < other.statement_index {
2671 // If we're in another block, then we want to check that block is a predecessor of `other`.
2672 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).clone();
2673 let mut visited = FxHashSet::default();
2675 while let Some(block) = queue.pop() {
2676 // If we haven't visited this block before, then make sure we visit it's predecessors.
2677 if visited.insert(block) {
2678 queue.append(&mut body.predecessors_for(block).clone());
2683 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2684 // we found that block by looking at the predecessors of `other`).
2685 if self.block == block {
2693 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2694 if self.block == other.block {
2695 self.statement_index <= other.statement_index
2697 dominators.is_dominated_by(other.block, self.block)
2702 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2703 pub enum UnsafetyViolationKind {
2705 /// Permitted both in `const fn`s and regular `fn`s.
2707 BorrowPacked(hir::HirId),
2710 #[derive(Copy, Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2711 pub struct UnsafetyViolation {
2712 pub source_info: SourceInfo,
2713 pub description: Symbol,
2714 pub details: Symbol,
2715 pub kind: UnsafetyViolationKind,
2718 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2719 pub struct UnsafetyCheckResult {
2720 /// Violations that are propagated *upwards* from this function.
2721 pub violations: Lrc<[UnsafetyViolation]>,
2722 /// `unsafe` blocks in this function, along with whether they are used. This is
2723 /// used for the "unused_unsafe" lint.
2724 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2727 rustc_index::newtype_index! {
2728 pub struct GeneratorSavedLocal {
2730 DEBUG_FORMAT = "_{}",
2734 /// The layout of generator state.
2735 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable, TypeFoldable)]
2736 pub struct GeneratorLayout<'tcx> {
2737 /// The type of every local stored inside the generator.
2738 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2740 /// Which of the above fields are in each variant. Note that one field may
2741 /// be stored in multiple variants.
2742 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2744 /// Which saved locals are storage-live at the same time. Locals that do not
2745 /// have conflicts with each other are allowed to overlap in the computed
2747 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2749 /// The names and scopes of all the stored generator locals.
2751 /// N.B., this is *strictly* a temporary hack for codegen
2752 /// debuginfo generation, and will be removed at some point.
2753 /// Do **NOT** use it for anything else, local information should not be
2754 /// in the MIR, please rely on local crate HIR or other side-channels.
2756 // FIXME(tmandry): see above.
2757 pub __local_debuginfo_codegen_only_do_not_use: IndexVec<GeneratorSavedLocal, LocalDecl<'tcx>>,
2760 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2761 pub struct BorrowCheckResult<'tcx> {
2762 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2763 pub used_mut_upvars: SmallVec<[Field; 8]>,
2766 /// The result of the `mir_const_qualif` query.
2768 /// Each field corresponds to an implementer of the `Qualif` trait in
2769 /// `librustc_mir/transform/check_consts/qualifs.rs`. See that file for more information on each
2771 #[derive(Clone, Copy, Debug, Default, RustcEncodable, RustcDecodable, HashStable)]
2772 pub struct ConstQualifs {
2773 pub has_mut_interior: bool,
2774 pub needs_drop: bool,
2777 /// After we borrow check a closure, we are left with various
2778 /// requirements that we have inferred between the free regions that
2779 /// appear in the closure's signature or on its field types. These
2780 /// requirements are then verified and proved by the closure's
2781 /// creating function. This struct encodes those requirements.
2783 /// The requirements are listed as being between various
2784 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2785 /// vids refer to the free regions that appear in the closure (or
2786 /// generator's) type, in order of appearance. (This numbering is
2787 /// actually defined by the `UniversalRegions` struct in the NLL
2788 /// region checker. See for example
2789 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2790 /// regions in the closure's type "as if" they were erased, so their
2791 /// precise identity is not important, only their position.
2793 /// Example: If type check produces a closure with the closure substs:
2796 /// ClosureSubsts = [
2797 /// i8, // the "closure kind"
2798 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2799 /// &'a String, // some upvar
2803 /// here, there is one unique free region (`'a`) but it appears
2804 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2807 /// ClosureSubsts = [
2808 /// i8, // the "closure kind"
2809 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2810 /// &'2 String, // some upvar
2814 /// Now the code might impose a requirement like `'1: '2`. When an
2815 /// instance of the closure is created, the corresponding free regions
2816 /// can be extracted from its type and constrained to have the given
2817 /// outlives relationship.
2819 /// In some cases, we have to record outlives requirements between
2820 /// types and regions as well. In that case, if those types include
2821 /// any regions, those regions are recorded as `ReClosureBound`
2822 /// instances assigned one of these same indices. Those regions will
2823 /// be substituted away by the creator. We use `ReClosureBound` in
2824 /// that case because the regions must be allocated in the global
2825 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2826 /// internally within the rest of the NLL code).
2827 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2828 pub struct ClosureRegionRequirements<'tcx> {
2829 /// The number of external regions defined on the closure. In our
2830 /// example above, it would be 3 -- one for `'static`, then `'1`
2831 /// and `'2`. This is just used for a sanity check later on, to
2832 /// make sure that the number of regions we see at the callsite
2834 pub num_external_vids: usize,
2836 /// Requirements between the various free regions defined in
2838 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2841 /// Indicates an outlives-constraint between a type or between two
2842 /// free regions declared on the closure.
2843 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2844 pub struct ClosureOutlivesRequirement<'tcx> {
2845 // This region or type ...
2846 pub subject: ClosureOutlivesSubject<'tcx>,
2848 // ... must outlive this one.
2849 pub outlived_free_region: ty::RegionVid,
2851 // If not, report an error here ...
2852 pub blame_span: Span,
2854 // ... due to this reason.
2855 pub category: ConstraintCategory,
2858 /// Outlives-constraints can be categorized to determine whether and why they
2859 /// are interesting (for error reporting). Order of variants indicates sort
2860 /// order of the category, thereby influencing diagnostic output.
2862 /// See also [rustc_mir::borrow_check::nll::constraints].
2876 pub enum ConstraintCategory {
2884 /// A constraint that came from checking the body of a closure.
2886 /// We try to get the category that the closure used when reporting this.
2894 /// A "boring" constraint (caused by the given location) is one that
2895 /// the user probably doesn't want to see described in diagnostics,
2896 /// because it is kind of an artifact of the type system setup.
2897 /// Example: `x = Foo { field: y }` technically creates
2898 /// intermediate regions representing the "type of `Foo { field: y
2899 /// }`", and data flows from `y` into those variables, but they
2900 /// are not very interesting. The assignment into `x` on the other
2903 // Boring and applicable everywhere.
2906 /// A constraint that doesn't correspond to anything the user sees.
2910 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2911 /// that must outlive some region.
2912 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2913 pub enum ClosureOutlivesSubject<'tcx> {
2914 /// Subject is a type, typically a type parameter, but could also
2915 /// be a projection. Indicates a requirement like `T: 'a` being
2916 /// passed to the caller, where the type here is `T`.
2918 /// The type here is guaranteed not to contain any free regions at
2922 /// Subject is a free region from the closure. Indicates a requirement
2923 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2924 Region(ty::RegionVid),
2928 * `TypeFoldable` implementations for MIR types
2931 CloneTypeFoldableAndLiftImpls! {
2941 SourceScopeLocalData,
2942 UserTypeAnnotationIndex,
2945 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2946 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2947 use crate::mir::TerminatorKind::*;
2949 let kind = match self.kind {
2950 Goto { target } => Goto { target },
2951 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
2952 discr: discr.fold_with(folder),
2953 switch_ty: switch_ty.fold_with(folder),
2954 values: values.clone(),
2955 targets: targets.clone(),
2957 Drop { ref location, target, unwind } => {
2958 Drop { location: location.fold_with(folder), target, unwind }
2960 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
2961 location: location.fold_with(folder),
2962 value: value.fold_with(folder),
2966 Yield { ref value, resume, drop } => {
2967 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
2969 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
2971 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2974 func: func.fold_with(folder),
2975 args: args.fold_with(folder),
2981 Assert { ref cond, expected, ref msg, target, cleanup } => {
2983 let msg = match msg {
2984 BoundsCheck { ref len, ref index } =>
2986 len: len.fold_with(folder),
2987 index: index.fold_with(folder),
2989 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
2990 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
2993 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
2995 GeneratorDrop => GeneratorDrop,
2999 Unreachable => Unreachable,
3000 FalseEdges { real_target, imaginary_target } => {
3001 FalseEdges { real_target, imaginary_target }
3003 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
3005 Terminator { source_info: self.source_info, kind }
3008 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3009 use crate::mir::TerminatorKind::*;
3012 SwitchInt { ref discr, switch_ty, .. } => {
3013 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
3015 Drop { ref location, .. } => location.visit_with(visitor),
3016 DropAndReplace { ref location, ref value, .. } => {
3017 location.visit_with(visitor) || value.visit_with(visitor)
3019 Yield { ref value, .. } => value.visit_with(visitor),
3020 Call { ref func, ref args, ref destination, .. } => {
3021 let dest = if let Some((ref loc, _)) = *destination {
3022 loc.visit_with(visitor)
3026 dest || func.visit_with(visitor) || args.visit_with(visitor)
3028 Assert { ref cond, ref msg, .. } => {
3029 if cond.visit_with(visitor) {
3032 BoundsCheck { ref len, ref index } =>
3033 len.visit_with(visitor) || index.visit_with(visitor),
3034 Panic { .. } | Overflow(_) | OverflowNeg |
3035 DivisionByZero | RemainderByZero |
3036 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
3050 | FalseUnwind { .. } => false,
3055 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3056 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3058 base: self.base.fold_with(folder),
3059 projection: self.projection.fold_with(folder),
3063 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3064 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3068 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3069 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3071 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3072 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3076 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3078 PlaceBase::Local(local) => local.visit_with(visitor),
3079 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3084 impl<'tcx> TypeFoldable<'tcx> for &'tcx ty::List<PlaceElem<'tcx>> {
3085 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3086 let v = self.iter().map(|t| t.fold_with(folder)).collect::<Vec<_>>();
3087 folder.tcx().intern_place_elems(&v)
3090 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3091 self.iter().any(|t| t.visit_with(visitor))
3095 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3096 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3098 ty: self.ty.fold_with(folder),
3099 kind: self.kind.fold_with(folder),
3100 def_id: self.def_id,
3104 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3105 let Static { ty, kind, def_id: _ } = self;
3107 ty.visit_with(visitor) || kind.visit_with(visitor)
3111 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3112 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3114 StaticKind::Promoted(promoted, substs) =>
3115 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3116 StaticKind::Static => StaticKind::Static
3120 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3122 StaticKind::Promoted(promoted, substs) =>
3123 promoted.visit_with(visitor) || substs.visit_with(visitor),
3124 StaticKind::Static => { false }
3129 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3130 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3131 use crate::mir::Rvalue::*;
3133 Use(ref op) => Use(op.fold_with(folder)),
3134 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3135 Ref(region, bk, ref place) => {
3136 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3138 Len(ref place) => Len(place.fold_with(folder)),
3139 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3140 BinaryOp(op, ref rhs, ref lhs) => {
3141 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3143 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3144 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3146 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3147 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3148 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3149 Aggregate(ref kind, ref fields) => {
3150 let kind = box match **kind {
3151 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3152 AggregateKind::Tuple => AggregateKind::Tuple,
3153 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3156 substs.fold_with(folder),
3157 user_ty.fold_with(folder),
3160 AggregateKind::Closure(id, substs) => {
3161 AggregateKind::Closure(id, substs.fold_with(folder))
3163 AggregateKind::Generator(id, substs, movablity) => {
3164 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3167 Aggregate(kind, fields.fold_with(folder))
3172 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3173 use crate::mir::Rvalue::*;
3175 Use(ref op) => op.visit_with(visitor),
3176 Repeat(ref op, _) => op.visit_with(visitor),
3177 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3178 Len(ref place) => place.visit_with(visitor),
3179 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3180 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3181 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3183 UnaryOp(_, ref val) => val.visit_with(visitor),
3184 Discriminant(ref place) => place.visit_with(visitor),
3185 NullaryOp(_, ty) => ty.visit_with(visitor),
3186 Aggregate(ref kind, ref fields) => {
3188 AggregateKind::Array(ty) => ty.visit_with(visitor),
3189 AggregateKind::Tuple => false,
3190 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3191 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3193 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3194 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3195 }) || fields.visit_with(visitor)
3201 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3202 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3204 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3205 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3206 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3210 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3212 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3213 Operand::Constant(ref c) => c.visit_with(visitor),
3218 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3219 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3220 use crate::mir::ProjectionElem::*;
3224 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3225 Index(v) => Index(v.fold_with(folder)),
3226 elem => elem.clone(),
3230 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3231 use crate::mir::ProjectionElem::*;
3234 Field(_, ty) => ty.visit_with(visitor),
3235 Index(v) => v.visit_with(visitor),
3241 impl<'tcx> TypeFoldable<'tcx> for Field {
3242 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3245 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3250 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3251 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3254 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3259 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3260 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3263 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3268 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3269 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3271 span: self.span.clone(),
3272 user_ty: self.user_ty.fold_with(folder),
3273 literal: self.literal.fold_with(folder),
3276 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3277 self.literal.visit_with(visitor)