1 // ignore-tidy-filelength
3 //! MIR datatypes and passes. See the [rustc guide] for more info.
5 //! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
7 use crate::hir::def::{CtorKind, Namespace};
8 use crate::hir::def_id::DefId;
9 use crate::hir::{self, InlineAsm as HirInlineAsm};
10 use crate::mir::interpret::{ConstValue, PanicInfo, Scalar};
11 use crate::mir::visit::MirVisitable;
12 use crate::ty::adjustment::PointerCast;
13 use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
14 use crate::ty::layout::VariantIdx;
15 use crate::ty::print::{FmtPrinter, Printer};
16 use crate::ty::subst::{Subst, SubstsRef};
18 self, AdtDef, CanonicalUserTypeAnnotations, Region, Ty, TyCtxt,
19 UserTypeAnnotationIndex,
22 use polonius_engine::Atom;
23 use rustc_index::bit_set::BitMatrix;
24 use rustc_data_structures::fx::FxHashSet;
25 use rustc_data_structures::graph::dominators::{dominators, Dominators};
26 use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
27 use rustc_index::vec::{Idx, IndexVec};
28 use rustc_data_structures::sync::Lrc;
29 use rustc_data_structures::sync::MappedReadGuard;
30 use rustc_macros::HashStable;
31 use rustc_serialize::{Encodable, Decodable};
32 use smallvec::SmallVec;
34 use std::fmt::{self, Debug, Display, Formatter, Write};
35 use std::ops::{Index, IndexMut};
37 use std::vec::IntoIter;
38 use std::{iter, mem, option, u32};
39 use syntax::ast::Name;
40 use syntax::symbol::{InternedString, Symbol};
41 use syntax_pos::{Span, DUMMY_SP};
43 pub use crate::mir::interpret::AssertMessage;
53 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
55 pub trait HasLocalDecls<'tcx> {
56 fn local_decls(&self) -> &LocalDecls<'tcx>;
59 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
60 fn local_decls(&self) -> &LocalDecls<'tcx> {
65 impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
66 fn local_decls(&self) -> &LocalDecls<'tcx> {
71 /// The various "big phases" that MIR goes through.
73 /// Warning: ordering of variants is significant.
74 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, PartialOrd, Ord)]
83 /// Gets the index of the current MirPhase within the set of all `MirPhase`s.
84 pub fn phase_index(&self) -> usize {
89 /// The lowered representation of a single function.
90 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
91 pub struct Body<'tcx> {
92 /// A list of basic blocks. References to basic block use a newtyped index type `BasicBlock`
93 /// that indexes into this vector.
94 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
96 /// Records how far through the "desugaring and optimization" process this particular
97 /// MIR has traversed. This is particularly useful when inlining, since in that context
98 /// we instantiate the promoted constants and add them to our promoted vector -- but those
99 /// promoted items have already been optimized, whereas ours have not. This field allows
100 /// us to see the difference and forego optimization on the inlined promoted items.
103 /// A list of source scopes; these are referenced by statements
104 /// and used for debuginfo. Indexed by a `SourceScope`.
105 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
107 /// Crate-local information for each source scope, that can't (and
108 /// needn't) be tracked across crates.
109 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
111 /// The yield type of the function, if it is a generator.
112 pub yield_ty: Option<Ty<'tcx>>,
114 /// Generator drop glue.
115 pub generator_drop: Option<Box<Body<'tcx>>>,
117 /// The layout of a generator. Produced by the state transformation.
118 pub generator_layout: Option<GeneratorLayout<'tcx>>,
120 /// Declarations of locals.
122 /// The first local is the return value pointer, followed by `arg_count`
123 /// locals for the function arguments, followed by any user-declared
124 /// variables and temporaries.
125 pub local_decls: LocalDecls<'tcx>,
127 /// User type annotations.
128 pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
130 /// The number of arguments this function takes.
132 /// Starting at local 1, `arg_count` locals will be provided by the caller
133 /// and can be assumed to be initialized.
135 /// If this MIR was built for a constant, this will be 0.
136 pub arg_count: usize,
138 /// Mark an argument local (which must be a tuple) as getting passed as
139 /// its individual components at the LLVM level.
141 /// This is used for the "rust-call" ABI.
142 pub spread_arg: Option<Local>,
144 /// Names and capture modes of all the closure upvars, assuming
145 /// the first argument is either the closure or a reference to it.
147 // NOTE(eddyb) This is *strictly* a temporary hack for codegen
148 // debuginfo generation, and will be removed at some point.
149 // Do **NOT** use it for anything else; upvar information should not be
150 // in the MIR, so please rely on local crate HIR or other side-channels.
151 pub __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
153 /// Mark this MIR of a const context other than const functions as having converted a `&&` or
154 /// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
155 /// this conversion from happening and use short circuiting, we will cause the following code
156 /// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
158 /// List of places where control flow was destroyed. Used for error reporting.
159 pub control_flow_destroyed: Vec<(Span, String)>,
161 /// A span representing this MIR, for error reporting.
164 /// A cache for various calculations.
168 impl<'tcx> Body<'tcx> {
170 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
171 source_scopes: IndexVec<SourceScope, SourceScopeData>,
172 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
173 yield_ty: Option<Ty<'tcx>>,
174 local_decls: LocalDecls<'tcx>,
175 user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
177 __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
179 control_flow_destroyed: Vec<(Span, String)>,
181 // We need `arg_count` locals, and one for the return place.
183 local_decls.len() >= arg_count + 1,
184 "expected at least {} locals, got {}",
190 phase: MirPhase::Build,
193 source_scope_local_data,
195 generator_drop: None,
196 generator_layout: None,
198 user_type_annotations,
200 __upvar_debuginfo_codegen_only_do_not_use,
203 cache: cache::Cache::new(),
204 control_flow_destroyed,
209 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
214 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
215 self.cache.invalidate();
216 &mut self.basic_blocks
220 pub fn basic_blocks_and_local_decls_mut(
222 ) -> (&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>, &mut LocalDecls<'tcx>) {
223 self.cache.invalidate();
224 (&mut self.basic_blocks, &mut self.local_decls)
228 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
229 self.cache.predecessors(self)
233 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
234 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
238 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
239 let if_zero_locations = if loc.statement_index == 0 {
240 let predecessor_blocks = self.predecessors_for(loc.block);
241 let num_predecessor_blocks = predecessor_blocks.len();
243 (0..num_predecessor_blocks)
244 .map(move |i| predecessor_blocks[i])
245 .map(move |bb| self.terminator_loc(bb)),
251 let if_not_zero_locations = if loc.statement_index == 0 {
254 Some(Location { block: loc.block, statement_index: loc.statement_index - 1 })
257 if_zero_locations.into_iter().flatten().chain(if_not_zero_locations)
261 pub fn dominators(&self) -> Dominators<BasicBlock> {
265 /// Returns `true` if a cycle exists in the control-flow graph that is reachable from the
267 pub fn is_cfg_cyclic(&self) -> bool {
268 graph::is_cyclic(self)
272 pub fn local_kind(&self, local: Local) -> LocalKind {
273 let index = local.as_usize();
276 self.local_decls[local].mutability == Mutability::Mut,
277 "return place should be mutable"
280 LocalKind::ReturnPointer
281 } else if index < self.arg_count + 1 {
283 } else if self.local_decls[local].name.is_some() {
290 /// Returns an iterator over all temporaries.
292 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
293 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
294 let local = Local::new(index);
295 if self.local_decls[local].is_user_variable.is_some() {
303 /// Returns an iterator over all user-declared locals.
305 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
306 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
307 let local = Local::new(index);
308 if self.local_decls[local].is_user_variable.is_some() {
316 /// Returns an iterator over all user-declared mutable locals.
318 pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
319 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
320 let local = Local::new(index);
321 let decl = &self.local_decls[local];
322 if decl.is_user_variable.is_some() && decl.mutability == Mutability::Mut {
330 /// Returns an iterator over all user-declared mutable arguments and locals.
332 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
333 (1..self.local_decls.len()).filter_map(move |index| {
334 let local = Local::new(index);
335 let decl = &self.local_decls[local];
336 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
337 && decl.mutability == Mutability::Mut
346 /// Returns an iterator over all function arguments.
348 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
349 let arg_count = self.arg_count;
350 (1..=arg_count).map(Local::new)
353 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
354 /// locals that are neither arguments nor the return place).
356 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
357 let arg_count = self.arg_count;
358 let local_count = self.local_decls.len();
359 (arg_count + 1..local_count).map(Local::new)
362 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
363 /// invalidating statement indices in `Location`s.
364 pub fn make_statement_nop(&mut self, location: Location) {
365 let block = &mut self[location.block];
366 debug_assert!(location.statement_index < block.statements.len());
367 block.statements[location.statement_index].make_nop()
370 /// Returns the source info associated with `location`.
371 pub fn source_info(&self, location: Location) -> &SourceInfo {
372 let block = &self[location.block];
373 let stmts = &block.statements;
374 let idx = location.statement_index;
375 if idx < stmts.len() {
376 &stmts[idx].source_info
378 assert_eq!(idx, stmts.len());
379 &block.terminator().source_info
383 /// Checks if `sub` is a sub scope of `sup`
384 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
386 match self.source_scopes[sub].parent_scope {
387 None => return false,
394 /// Returns the return type; it always return first element from `local_decls` array.
395 pub fn return_ty(&self) -> Ty<'tcx> {
396 self.local_decls[RETURN_PLACE].ty
399 /// Gets the location of the terminator for the given block.
400 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
401 Location { block: bb, statement_index: self[bb].statements.len() }
405 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
408 /// Unsafe because of a PushUnsafeBlock
410 /// Unsafe because of an unsafe fn
412 /// Unsafe because of an `unsafe` block
413 ExplicitUnsafe(hir::HirId),
416 impl_stable_hash_for!(struct Body<'tcx> {
420 source_scope_local_data,
425 user_type_annotations,
427 __upvar_debuginfo_codegen_only_do_not_use,
429 control_flow_destroyed,
434 impl<'tcx> Index<BasicBlock> for Body<'tcx> {
435 type Output = BasicBlockData<'tcx>;
438 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
439 &self.basic_blocks()[index]
443 impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
445 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
446 &mut self.basic_blocks_mut()[index]
450 #[derive(Copy, Clone, Debug, HashStable)]
451 pub enum ClearCrossCrate<T> {
456 impl<T> ClearCrossCrate<T> {
457 pub fn assert_crate_local(self) -> T {
459 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
460 ClearCrossCrate::Set(v) => v,
465 impl<T: Encodable> rustc_serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
466 impl<T: Decodable> rustc_serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
468 /// Grouped information about the source code origin of a MIR entity.
469 /// Intended to be inspected by diagnostics and debuginfo.
470 /// Most passes can work with it as a whole, within a single function.
471 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, HashStable)]
472 pub struct SourceInfo {
473 /// The source span for the AST pertaining to this MIR entity.
476 /// The source scope, keeping track of which bindings can be
477 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
478 pub scope: SourceScope,
481 ///////////////////////////////////////////////////////////////////////////
482 // Mutability and borrow kinds
484 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
485 pub enum Mutability {
490 impl From<Mutability> for hir::Mutability {
491 fn from(m: Mutability) -> Self {
493 Mutability::Mut => hir::MutMutable,
494 Mutability::Not => hir::MutImmutable,
500 Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable, HashStable,
502 pub enum BorrowKind {
503 /// Data must be immutable and is aliasable.
506 /// The immediately borrowed place must be immutable, but projections from
507 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
508 /// conflict with a mutable borrow of `a.b.c`.
510 /// This is used when lowering matches: when matching on a place we want to
511 /// ensure that place have the same value from the start of the match until
512 /// an arm is selected. This prevents this code from compiling:
514 /// let mut x = &Some(0);
517 /// Some(_) if { x = &None; false } => (),
521 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
522 /// should not prevent `if let None = x { ... }`, for example, because the
523 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
524 /// We can also report errors with this kind of borrow differently.
527 /// Data must be immutable but not aliasable. This kind of borrow
528 /// cannot currently be expressed by the user and is used only in
529 /// implicit closure bindings. It is needed when the closure is
530 /// borrowing or mutating a mutable referent, e.g.:
532 /// let x: &mut isize = ...;
533 /// let y = || *x += 5;
535 /// If we were to try to translate this closure into a more explicit
536 /// form, we'd encounter an error with the code as written:
538 /// struct Env { x: & &mut isize }
539 /// let x: &mut isize = ...;
540 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
541 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
543 /// This is then illegal because you cannot mutate an `&mut` found
544 /// in an aliasable location. To solve, you'd have to translate with
545 /// an `&mut` borrow:
547 /// struct Env { x: & &mut isize }
548 /// let x: &mut isize = ...;
549 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
550 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
552 /// Now the assignment to `**env.x` is legal, but creating a
553 /// mutable pointer to `x` is not because `x` is not mutable. We
554 /// could fix this by declaring `x` as `let mut x`. This is ok in
555 /// user code, if awkward, but extra weird for closures, since the
556 /// borrow is hidden.
558 /// So we introduce a "unique imm" borrow -- the referent is
559 /// immutable, but not aliasable. This solves the problem. For
560 /// simplicity, we don't give users the way to express this
561 /// borrow, it's just used when translating closures.
564 /// Data is mutable and not aliasable.
566 /// `true` if this borrow arose from method-call auto-ref
567 /// (i.e., `adjustment::Adjust::Borrow`).
568 allow_two_phase_borrow: bool,
573 pub fn allows_two_phase_borrow(&self) -> bool {
575 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
576 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
581 ///////////////////////////////////////////////////////////////////////////
582 // Variables and temps
584 rustc_index::newtype_index! {
587 DEBUG_FORMAT = "_{}",
588 const RETURN_PLACE = 0,
592 impl Atom for Local {
593 fn index(self) -> usize {
598 /// Classifies locals into categories. See `Body::local_kind`.
599 #[derive(PartialEq, Eq, Debug, HashStable)]
601 /// User-declared variable binding.
603 /// Compiler-introduced temporary.
605 /// Function argument.
607 /// Location of function's return value.
611 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
612 pub struct VarBindingForm<'tcx> {
613 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
614 pub binding_mode: ty::BindingMode,
615 /// If an explicit type was provided for this variable binding,
616 /// this holds the source Span of that type.
618 /// NOTE: if you want to change this to a `HirId`, be wary that
619 /// doing so breaks incremental compilation (as of this writing),
620 /// while a `Span` does not cause our tests to fail.
621 pub opt_ty_info: Option<Span>,
622 /// Place of the RHS of the =, or the subject of the `match` where this
623 /// variable is initialized. None in the case of `let PATTERN;`.
624 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
625 /// (a) the right-hand side isn't evaluated as a place expression.
626 /// (b) it gives a way to separate this case from the remaining cases
628 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
629 /// The span of the pattern in which this variable was bound.
633 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
634 pub enum BindingForm<'tcx> {
635 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
636 Var(VarBindingForm<'tcx>),
637 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
638 ImplicitSelf(ImplicitSelfKind),
639 /// Reference used in a guard expression to ensure immutability.
643 /// Represents what type of implicit self a function has, if any.
644 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
645 pub enum ImplicitSelfKind {
646 /// Represents a `fn x(self);`.
648 /// Represents a `fn x(mut self);`.
650 /// Represents a `fn x(&self);`.
652 /// Represents a `fn x(&mut self);`.
654 /// Represents when a function does not have a self argument or
655 /// when a function has a `self: X` argument.
659 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
661 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
668 impl_stable_hash_for!(enum self::ImplicitSelfKind {
676 impl_stable_hash_for!(enum self::MirPhase {
683 mod binding_form_impl {
684 use crate::ich::StableHashingContext;
685 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
687 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
688 fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
689 use super::BindingForm::*;
690 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
693 Var(binding) => binding.hash_stable(hcx, hasher),
694 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
701 /// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
702 /// created during evaluation of expressions in a block tail
703 /// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
705 /// It is used to improve diagnostics when such temporaries are
706 /// involved in borrow_check errors, e.g., explanations of where the
707 /// temporaries come from, when their destructors are run, and/or how
708 /// one might revise the code to satisfy the borrow checker's rules.
709 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
710 pub struct BlockTailInfo {
711 /// If `true`, then the value resulting from evaluating this tail
712 /// expression is ignored by the block's expression context.
714 /// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
715 /// but not e.g., `let _x = { ...; tail };`
716 pub tail_result_is_ignored: bool,
719 impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
723 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
724 /// argument, or the return place.
725 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
726 pub struct LocalDecl<'tcx> {
727 /// Whether this is a mutable minding (i.e., `let x` or `let mut x`).
729 /// Temporaries and the return place are always mutable.
730 pub mutability: Mutability,
732 /// `Some(binding_mode)` if this corresponds to a user-declared local variable.
734 /// This is solely used for local diagnostics when generating
735 /// warnings/errors when compiling the current crate, and
736 /// therefore it need not be visible across crates. pnkfelix
737 /// currently hypothesized we *need* to wrap this in a
738 /// `ClearCrossCrate` as long as it carries as `HirId`.
739 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
741 /// `true` if this is an internal local.
743 /// These locals are not based on types in the source code and are only used
744 /// for a few desugarings at the moment.
746 /// The generator transformation will sanity check the locals which are live
747 /// across a suspension point against the type components of the generator
748 /// which type checking knows are live across a suspension point. We need to
749 /// flag drop flags to avoid triggering this check as they are introduced
752 /// Unsafety checking will also ignore dereferences of these locals,
753 /// so they can be used for raw pointers only used in a desugaring.
755 /// This should be sound because the drop flags are fully algebraic, and
756 /// therefore don't affect the OIBIT or outlives properties of the
760 /// If this local is a temporary and `is_block_tail` is `Some`,
761 /// then it is a temporary created for evaluation of some
762 /// subexpression of some block's tail expression (with no
763 /// intervening statement context).
764 pub is_block_tail: Option<BlockTailInfo>,
766 /// The type of this local.
769 /// If the user manually ascribed a type to this variable,
770 /// e.g., via `let x: T`, then we carry that type here. The MIR
771 /// borrow checker needs this information since it can affect
772 /// region inference.
773 pub user_ty: UserTypeProjections,
775 /// The name of the local, used in debuginfo and pretty-printing.
777 /// Note that function arguments can also have this set to `Some(_)`
778 /// to generate better debuginfo.
779 pub name: Option<Name>,
781 /// The *syntactic* (i.e., not visibility) source scope the local is defined
782 /// in. If the local was defined in a let-statement, this
783 /// is *within* the let-statement, rather than outside
786 /// This is needed because the visibility source scope of locals within
787 /// a let-statement is weird.
789 /// The reason is that we want the local to be *within* the let-statement
790 /// for lint purposes, but we want the local to be *after* the let-statement
791 /// for names-in-scope purposes.
793 /// That's it, if we have a let-statement like the one in this
797 /// fn foo(x: &str) {
798 /// #[allow(unused_mut)]
799 /// let mut x: u32 = { // <- one unused mut
800 /// let mut y: u32 = x.parse().unwrap();
807 /// Then, from a lint point of view, the declaration of `x: u32`
808 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
809 /// lint scopes are the same as the AST/HIR nesting.
811 /// However, from a name lookup point of view, the scopes look more like
812 /// as if the let-statements were `match` expressions:
815 /// fn foo(x: &str) {
817 /// match x.parse().unwrap() {
826 /// We care about the name-lookup scopes for debuginfo - if the
827 /// debuginfo instruction pointer is at the call to `x.parse()`, we
828 /// want `x` to refer to `x: &str`, but if it is at the call to
829 /// `drop(x)`, we want it to refer to `x: u32`.
831 /// To allow both uses to work, we need to have more than a single scope
832 /// for a local. We have the `source_info.scope` represent the
833 /// "syntactic" lint scope (with a variable being under its let
834 /// block) while the `visibility_scope` represents the "local variable"
835 /// scope (where the "rest" of a block is under all prior let-statements).
837 /// The end result looks like this:
841 /// │{ argument x: &str }
843 /// │ │{ #[allow(unused_mut)] } // This is actually split into 2 scopes
844 /// │ │ // in practice because I'm lazy.
846 /// │ │← x.source_info.scope
847 /// │ │← `x.parse().unwrap()`
849 /// │ │ │← y.source_info.scope
851 /// │ │ │{ let y: u32 }
853 /// │ │ │← y.visibility_scope
856 /// │ │{ let x: u32 }
857 /// │ │← x.visibility_scope
858 /// │ │← `drop(x)` // This accesses `x: u32`.
860 pub source_info: SourceInfo,
862 /// Source scope within which the local is visible (for debuginfo)
863 /// (see `source_info` for more details).
864 pub visibility_scope: SourceScope,
867 impl<'tcx> LocalDecl<'tcx> {
868 /// Returns `true` only if local is a binding that can itself be
869 /// made mutable via the addition of the `mut` keyword, namely
870 /// something like the occurrences of `x` in:
871 /// - `fn foo(x: Type) { ... }`,
873 /// - or `match ... { C(x) => ... }`
874 pub fn can_be_made_mutable(&self) -> bool {
875 match self.is_user_variable {
876 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
877 binding_mode: ty::BindingMode::BindByValue(_),
883 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm))) => true,
889 /// Returns `true` if local is definitely not a `ref ident` or
890 /// `ref mut ident` binding. (Such bindings cannot be made into
891 /// mutable bindings, but the inverse does not necessarily hold).
892 pub fn is_nonref_binding(&self) -> bool {
893 match self.is_user_variable {
894 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
895 binding_mode: ty::BindingMode::BindByValue(_),
901 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
907 /// Returns `true` if this is a reference to a variable bound in a `match`
908 /// expression that is used to access said variable for the guard of the
910 pub fn is_ref_for_guard(&self) -> bool {
911 match self.is_user_variable {
912 Some(ClearCrossCrate::Set(BindingForm::RefForGuard)) => true,
917 /// Returns `true` is the local is from a compiler desugaring, e.g.,
918 /// `__next` from a `for` loop.
920 pub fn from_compiler_desugaring(&self) -> bool {
921 self.source_info.span.desugaring_kind().is_some()
924 /// Creates a new `LocalDecl` for a temporary.
926 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
927 Self::new_local(ty, Mutability::Mut, false, span)
930 /// Converts `self` into same `LocalDecl` except tagged as immutable.
932 pub fn immutable(mut self) -> Self {
933 self.mutability = Mutability::Not;
937 /// Converts `self` into same `LocalDecl` except tagged as internal temporary.
939 pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
940 assert!(self.is_block_tail.is_none());
941 self.is_block_tail = Some(info);
945 /// Creates a new `LocalDecl` for a internal temporary.
947 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
948 Self::new_local(ty, Mutability::Mut, true, span)
952 fn new_local(ty: Ty<'tcx>, mutability: Mutability, internal: bool, span: Span) -> Self {
956 user_ty: UserTypeProjections::none(),
958 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
959 visibility_scope: OUTERMOST_SOURCE_SCOPE,
961 is_user_variable: None,
966 /// Builds a `LocalDecl` for the return place.
968 /// This must be inserted into the `local_decls` list as the first local.
970 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
972 mutability: Mutability::Mut,
974 user_ty: UserTypeProjections::none(),
975 source_info: SourceInfo { span, scope: OUTERMOST_SOURCE_SCOPE },
976 visibility_scope: OUTERMOST_SOURCE_SCOPE,
979 name: None, // FIXME maybe we do want some name here?
980 is_user_variable: None,
985 /// A closure capture, with its name and mode.
986 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
987 pub struct UpvarDebuginfo {
988 pub debug_name: Name,
990 /// If true, the capture is behind a reference.
994 ///////////////////////////////////////////////////////////////////////////
997 rustc_index::newtype_index! {
998 pub struct BasicBlock {
1000 DEBUG_FORMAT = "bb{}",
1001 const START_BLOCK = 0,
1006 pub fn start_location(self) -> Location {
1007 Location { block: self, statement_index: 0 }
1011 ///////////////////////////////////////////////////////////////////////////
1012 // BasicBlockData and Terminator
1014 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1015 pub struct BasicBlockData<'tcx> {
1016 /// List of statements in this block.
1017 pub statements: Vec<Statement<'tcx>>,
1019 /// Terminator for this block.
1021 /// N.B., this should generally ONLY be `None` during construction.
1022 /// Therefore, you should generally access it via the
1023 /// `terminator()` or `terminator_mut()` methods. The only
1024 /// exception is that certain passes, such as `simplify_cfg`, swap
1025 /// out the terminator temporarily with `None` while they continue
1026 /// to recurse over the set of basic blocks.
1027 pub terminator: Option<Terminator<'tcx>>,
1029 /// If true, this block lies on an unwind path. This is used
1030 /// during codegen where distinct kinds of basic blocks may be
1031 /// generated (particularly for MSVC cleanup). Unwind blocks must
1032 /// only branch to other unwind blocks.
1033 pub is_cleanup: bool,
1036 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1037 pub struct Terminator<'tcx> {
1038 pub source_info: SourceInfo,
1039 pub kind: TerminatorKind<'tcx>,
1042 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1043 pub enum TerminatorKind<'tcx> {
1044 /// Block should have one successor in the graph; we jump there.
1045 Goto { target: BasicBlock },
1047 /// Operand evaluates to an integer; jump depending on its value
1048 /// to one of the targets, and otherwise fallback to `otherwise`.
1050 /// The discriminant value being tested.
1051 discr: Operand<'tcx>,
1053 /// The type of value being tested.
1054 switch_ty: Ty<'tcx>,
1056 /// Possible values. The locations to branch to in each case
1057 /// are found in the corresponding indices from the `targets` vector.
1058 values: Cow<'tcx, [u128]>,
1060 /// Possible branch sites. The last element of this vector is used
1061 /// for the otherwise branch, so targets.len() == values.len() + 1
1064 // This invariant is quite non-obvious and also could be improved.
1065 // One way to make this invariant is to have something like this instead:
1067 // branches: Vec<(ConstInt, BasicBlock)>,
1068 // otherwise: Option<BasicBlock> // exhaustive if None
1070 // However we’ve decided to keep this as-is until we figure a case
1071 // where some other approach seems to be strictly better than other.
1072 targets: Vec<BasicBlock>,
1075 /// Indicates that the landing pad is finished and unwinding should
1076 /// continue. Emitted by `build::scope::diverge_cleanup`.
1079 /// Indicates that the landing pad is finished and that the process
1080 /// should abort. Used to prevent unwinding for foreign items.
1083 /// Indicates a normal return. The return place should have
1084 /// been filled in by now. This should occur at most once.
1087 /// Indicates a terminator that can never be reached.
1090 /// Drop the `Place`.
1091 Drop { location: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> },
1093 /// Drop the `Place` and assign the new value over it. This ensures
1094 /// that the assignment to `P` occurs *even if* the destructor for
1095 /// place unwinds. Its semantics are best explained by the
1100 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1108 /// Drop(P, goto BB1, unwind BB2)
1111 /// // P is now uninitialized
1115 /// // P is now uninitialized -- its dtor panicked
1120 location: Place<'tcx>,
1121 value: Operand<'tcx>,
1123 unwind: Option<BasicBlock>,
1126 /// Block ends with a call of a converging function.
1128 /// The function that’s being called.
1129 func: Operand<'tcx>,
1130 /// Arguments the function is called with.
1131 /// These are owned by the callee, which is free to modify them.
1132 /// This allows the memory occupied by "by-value" arguments to be
1133 /// reused across function calls without duplicating the contents.
1134 args: Vec<Operand<'tcx>>,
1135 /// Destination for the return value. If some, the call is converging.
1136 destination: Option<(Place<'tcx>, BasicBlock)>,
1137 /// Cleanups to be done if the call unwinds.
1138 cleanup: Option<BasicBlock>,
1139 /// `true` if this is from a call in HIR rather than from an overloaded
1140 /// operator. True for overloaded function call.
1141 from_hir_call: bool,
1144 /// Jump to the target if the condition has the expected value,
1145 /// otherwise panic with a message and a cleanup target.
1147 cond: Operand<'tcx>,
1149 msg: AssertMessage<'tcx>,
1151 cleanup: Option<BasicBlock>,
1154 /// A suspend point.
1156 /// The value to return.
1157 value: Operand<'tcx>,
1158 /// Where to resume to.
1160 /// Cleanup to be done if the generator is dropped at this suspend point.
1161 drop: Option<BasicBlock>,
1164 /// Indicates the end of the dropping of a generator.
1167 /// A block where control flow only ever takes one real path, but borrowck
1168 /// needs to be more conservative.
1170 /// The target normal control flow will take.
1171 real_target: BasicBlock,
1172 /// A block control flow could conceptually jump to, but won't in
1174 imaginary_target: BasicBlock,
1176 /// A terminator for blocks that only take one path in reality, but where we
1177 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1178 /// This can arise in infinite loops with no function calls for example.
1180 /// The target normal control flow will take.
1181 real_target: BasicBlock,
1182 /// The imaginary cleanup block link. This particular path will never be taken
1183 /// in practice, but in order to avoid fragility we want to always
1184 /// consider it in borrowck. We don't want to accept programs which
1185 /// pass borrowck only when `panic=abort` or some assertions are disabled
1186 /// due to release vs. debug mode builds. This needs to be an `Option` because
1187 /// of the `remove_noop_landing_pads` and `no_landing_pads` passes.
1188 unwind: Option<BasicBlock>,
1192 pub type Successors<'a> =
1193 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1194 pub type SuccessorsMut<'a> =
1195 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1197 impl<'tcx> Terminator<'tcx> {
1198 pub fn successors(&self) -> Successors<'_> {
1199 self.kind.successors()
1202 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1203 self.kind.successors_mut()
1206 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1210 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1211 self.kind.unwind_mut()
1215 impl<'tcx> TerminatorKind<'tcx> {
1218 cond: Operand<'tcx>,
1221 ) -> TerminatorKind<'tcx> {
1222 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1223 TerminatorKind::SwitchInt {
1225 switch_ty: tcx.types.bool,
1226 values: From::from(BOOL_SWITCH_FALSE),
1227 targets: vec![f, t],
1231 pub fn successors(&self) -> Successors<'_> {
1232 use self::TerminatorKind::*;
1239 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&[]),
1240 Goto { target: ref t }
1241 | Call { destination: None, cleanup: Some(ref t), .. }
1242 | Call { destination: Some((_, ref t)), cleanup: None, .. }
1243 | Yield { resume: ref t, drop: None, .. }
1244 | DropAndReplace { target: ref t, unwind: None, .. }
1245 | Drop { target: ref t, unwind: None, .. }
1246 | Assert { target: ref t, cleanup: None, .. }
1247 | FalseUnwind { real_target: ref t, unwind: None } => Some(t).into_iter().chain(&[]),
1248 Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. }
1249 | Yield { resume: ref t, drop: Some(ref u), .. }
1250 | DropAndReplace { target: ref t, unwind: Some(ref u), .. }
1251 | Drop { target: ref t, unwind: Some(ref u), .. }
1252 | Assert { target: ref t, cleanup: Some(ref u), .. }
1253 | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => {
1254 Some(t).into_iter().chain(slice::from_ref(u))
1256 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1257 FalseEdges { ref real_target, ref imaginary_target } => {
1258 Some(real_target).into_iter().chain(slice::from_ref(imaginary_target))
1263 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1264 use self::TerminatorKind::*;
1271 | Call { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []),
1272 Goto { target: ref mut t }
1273 | Call { destination: None, cleanup: Some(ref mut t), .. }
1274 | Call { destination: Some((_, ref mut t)), cleanup: None, .. }
1275 | Yield { resume: ref mut t, drop: None, .. }
1276 | DropAndReplace { target: ref mut t, unwind: None, .. }
1277 | Drop { target: ref mut t, unwind: None, .. }
1278 | Assert { target: ref mut t, cleanup: None, .. }
1279 | FalseUnwind { real_target: ref mut t, unwind: None } => {
1280 Some(t).into_iter().chain(&mut [])
1282 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. }
1283 | Yield { resume: ref mut t, drop: Some(ref mut u), .. }
1284 | DropAndReplace { target: ref mut t, unwind: Some(ref mut u), .. }
1285 | Drop { target: ref mut t, unwind: Some(ref mut u), .. }
1286 | Assert { target: ref mut t, cleanup: Some(ref mut u), .. }
1287 | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } => {
1288 Some(t).into_iter().chain(slice::from_mut(u))
1290 SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]),
1291 FalseEdges { ref mut real_target, ref mut imaginary_target } => {
1292 Some(real_target).into_iter().chain(slice::from_mut(imaginary_target))
1297 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1299 TerminatorKind::Goto { .. }
1300 | TerminatorKind::Resume
1301 | TerminatorKind::Abort
1302 | TerminatorKind::Return
1303 | TerminatorKind::Unreachable
1304 | TerminatorKind::GeneratorDrop
1305 | TerminatorKind::Yield { .. }
1306 | TerminatorKind::SwitchInt { .. }
1307 | TerminatorKind::FalseEdges { .. } => None,
1308 TerminatorKind::Call { cleanup: ref unwind, .. }
1309 | TerminatorKind::Assert { cleanup: ref unwind, .. }
1310 | TerminatorKind::DropAndReplace { ref unwind, .. }
1311 | TerminatorKind::Drop { ref unwind, .. }
1312 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1316 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1318 TerminatorKind::Goto { .. }
1319 | TerminatorKind::Resume
1320 | TerminatorKind::Abort
1321 | TerminatorKind::Return
1322 | TerminatorKind::Unreachable
1323 | TerminatorKind::GeneratorDrop
1324 | TerminatorKind::Yield { .. }
1325 | TerminatorKind::SwitchInt { .. }
1326 | TerminatorKind::FalseEdges { .. } => None,
1327 TerminatorKind::Call { cleanup: ref mut unwind, .. }
1328 | TerminatorKind::Assert { cleanup: ref mut unwind, .. }
1329 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1330 | TerminatorKind::Drop { ref mut unwind, .. }
1331 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1336 impl<'tcx> BasicBlockData<'tcx> {
1337 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1338 BasicBlockData { statements: vec![], terminator, is_cleanup: false }
1341 /// Accessor for terminator.
1343 /// Terminator may not be None after construction of the basic block is complete. This accessor
1344 /// provides a convenience way to reach the terminator.
1345 pub fn terminator(&self) -> &Terminator<'tcx> {
1346 self.terminator.as_ref().expect("invalid terminator state")
1349 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1350 self.terminator.as_mut().expect("invalid terminator state")
1353 pub fn retain_statements<F>(&mut self, mut f: F)
1355 F: FnMut(&mut Statement<'_>) -> bool,
1357 for s in &mut self.statements {
1364 pub fn expand_statements<F, I>(&mut self, mut f: F)
1366 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1367 I: iter::TrustedLen<Item = Statement<'tcx>>,
1369 // Gather all the iterators we'll need to splice in, and their positions.
1370 let mut splices: Vec<(usize, I)> = vec![];
1371 let mut extra_stmts = 0;
1372 for (i, s) in self.statements.iter_mut().enumerate() {
1373 if let Some(mut new_stmts) = f(s) {
1374 if let Some(first) = new_stmts.next() {
1375 // We can already store the first new statement.
1378 // Save the other statements for optimized splicing.
1379 let remaining = new_stmts.size_hint().0;
1381 splices.push((i + 1 + extra_stmts, new_stmts));
1382 extra_stmts += remaining;
1390 // Splice in the new statements, from the end of the block.
1391 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1392 // where a range of elements ("gap") is left uninitialized, with
1393 // splicing adding new elements to the end of that gap and moving
1394 // existing elements from before the gap to the end of the gap.
1395 // For now, this is safe code, emulating a gap but initializing it.
1396 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1397 self.statements.resize(
1400 source_info: SourceInfo { span: DUMMY_SP, scope: OUTERMOST_SOURCE_SCOPE },
1401 kind: StatementKind::Nop,
1404 for (splice_start, new_stmts) in splices.into_iter().rev() {
1405 let splice_end = splice_start + new_stmts.size_hint().0;
1406 while gap.end > splice_end {
1409 self.statements.swap(gap.start, gap.end);
1411 self.statements.splice(splice_start..splice_end, new_stmts);
1412 gap.end = splice_start;
1416 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1417 if index < self.statements.len() {
1418 &self.statements[index]
1425 impl<'tcx> Debug for TerminatorKind<'tcx> {
1426 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1427 self.fmt_head(fmt)?;
1428 let successor_count = self.successors().count();
1429 let labels = self.fmt_successor_labels();
1430 assert_eq!(successor_count, labels.len());
1432 match successor_count {
1435 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1438 write!(fmt, " -> [")?;
1439 for (i, target) in self.successors().enumerate() {
1443 write!(fmt, "{}: {:?}", labels[i], target)?;
1451 impl<'tcx> TerminatorKind<'tcx> {
1452 /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the
1453 /// successor basic block, if any. The only information not included is the list of possible
1454 /// successors, which may be rendered differently between the text and the graphviz format.
1455 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1456 use self::TerminatorKind::*;
1458 Goto { .. } => write!(fmt, "goto"),
1459 SwitchInt { discr: ref place, .. } => write!(fmt, "switchInt({:?})", place),
1460 Return => write!(fmt, "return"),
1461 GeneratorDrop => write!(fmt, "generator_drop"),
1462 Resume => write!(fmt, "resume"),
1463 Abort => write!(fmt, "abort"),
1464 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1465 Unreachable => write!(fmt, "unreachable"),
1466 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1467 DropAndReplace { ref location, ref value, .. } => {
1468 write!(fmt, "replace({:?} <- {:?})", location, value)
1470 Call { ref func, ref args, ref destination, .. } => {
1471 if let Some((ref destination, _)) = *destination {
1472 write!(fmt, "{:?} = ", destination)?;
1474 write!(fmt, "{:?}(", func)?;
1475 for (index, arg) in args.iter().enumerate() {
1479 write!(fmt, "{:?}", arg)?;
1483 Assert { ref cond, expected, ref msg, .. } => {
1484 write!(fmt, "assert(")?;
1488 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1490 FalseEdges { .. } => write!(fmt, "falseEdges"),
1491 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1495 /// Returns the list of labels for the edges to the successor basic blocks.
1496 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1497 use self::TerminatorKind::*;
1499 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1500 Goto { .. } => vec!["".into()],
1501 SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| {
1502 let param_env = ty::ParamEnv::empty();
1503 let switch_ty = tcx.lift(&switch_ty).unwrap();
1504 let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
1508 tcx.mk_const(ty::Const {
1509 val: ConstValue::Scalar(Scalar::from_uint(u, size).into()),
1515 .chain(iter::once("otherwise".into()))
1518 Call { destination: Some(_), cleanup: Some(_), .. } => {
1519 vec!["return".into(), "unwind".into()]
1521 Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()],
1522 Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()],
1523 Call { destination: None, cleanup: None, .. } => vec![],
1524 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1525 Yield { drop: None, .. } => vec!["resume".into()],
1526 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1527 vec!["return".into()]
1529 DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => {
1530 vec!["return".into(), "unwind".into()]
1532 Assert { cleanup: None, .. } => vec!["".into()],
1533 Assert { .. } => vec!["success".into(), "unwind".into()],
1534 FalseEdges { .. } => vec!["real".into(), "imaginary".into()],
1535 FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()],
1536 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1541 ///////////////////////////////////////////////////////////////////////////
1544 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
1545 pub struct Statement<'tcx> {
1546 pub source_info: SourceInfo,
1547 pub kind: StatementKind<'tcx>,
1550 // `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
1551 #[cfg(target_arch = "x86_64")]
1552 static_assert_size!(Statement<'_>, 32);
1554 impl Statement<'_> {
1555 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1556 /// invalidating statement indices in `Location`s.
1557 pub fn make_nop(&mut self) {
1558 self.kind = StatementKind::Nop
1561 /// Changes a statement to a nop and returns the original statement.
1562 pub fn replace_nop(&mut self) -> Self {
1564 source_info: self.source_info,
1565 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1570 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1571 pub enum StatementKind<'tcx> {
1572 /// Write the RHS Rvalue to the LHS Place.
1573 Assign(Box<(Place<'tcx>, Rvalue<'tcx>)>),
1575 /// This represents all the reading that a pattern match may do
1576 /// (e.g., inspecting constants and discriminant values), and the
1577 /// kind of pattern it comes from. This is in order to adapt potential
1578 /// error messages to these specific patterns.
1580 /// Note that this also is emitted for regular `let` bindings to ensure that locals that are
1581 /// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
1582 FakeRead(FakeReadCause, Box<Place<'tcx>>),
1584 /// Write the discriminant for a variant to the enum Place.
1585 SetDiscriminant { place: Box<Place<'tcx>>, variant_index: VariantIdx },
1587 /// Start a live range for the storage of the local.
1590 /// End the current live range for the storage of the local.
1593 /// Executes a piece of inline Assembly. Stored in a Box to keep the size
1594 /// of `StatementKind` low.
1595 InlineAsm(Box<InlineAsm<'tcx>>),
1597 /// Retag references in the given place, ensuring they got fresh tags. This is
1598 /// part of the Stacked Borrows model. These statements are currently only interpreted
1599 /// by miri and only generated when "-Z mir-emit-retag" is passed.
1600 /// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
1601 /// for more details.
1602 Retag(RetagKind, Box<Place<'tcx>>),
1604 /// Encodes a user's type ascription. These need to be preserved
1605 /// intact so that NLL can respect them. For example:
1609 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1610 /// to the user-given type `T`. The effect depends on the specified variance:
1612 /// - `Covariant` -- requires that `T_y <: T`
1613 /// - `Contravariant` -- requires that `T_y :> T`
1614 /// - `Invariant` -- requires that `T_y == T`
1615 /// - `Bivariant` -- no effect
1616 AscribeUserType(Box<(Place<'tcx>, UserTypeProjection)>, ty::Variance),
1618 /// No-op. Useful for deleting instructions without affecting statement indices.
1622 /// Describes what kind of retag is to be performed.
1623 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
1624 pub enum RetagKind {
1625 /// The initial retag when entering a function.
1627 /// Retag preparing for a two-phase borrow.
1629 /// Retagging raw pointers.
1631 /// A "normal" retag.
1635 /// The `FakeReadCause` describes the type of pattern why a FakeRead statement exists.
1636 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
1637 pub enum FakeReadCause {
1638 /// Inject a fake read of the borrowed input at the end of each guards
1641 /// This should ensure that you cannot change the variant for an enum while
1642 /// you are in the midst of matching on it.
1645 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1646 /// generate a read of x to check that it is initialized and safe.
1649 /// A fake read of the RefWithinGuard version of a bind-by-value variable
1650 /// in a match guard to ensure that it's value hasn't change by the time
1651 /// we create the OutsideGuard version.
1654 /// Officially, the semantics of
1656 /// `let pattern = <expr>;`
1658 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1659 /// into the pattern.
1661 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1662 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1663 /// but in some cases it can affect the borrow checker, as in #53695.
1664 /// Therefore, we insert a "fake read" here to ensure that we get
1665 /// appropriate errors.
1669 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
1670 pub struct InlineAsm<'tcx> {
1671 pub asm: HirInlineAsm,
1672 pub outputs: Box<[Place<'tcx>]>,
1673 pub inputs: Box<[(Span, Operand<'tcx>)]>,
1676 impl Debug for Statement<'_> {
1677 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1678 use self::StatementKind::*;
1680 Assign(box(ref place, ref rv)) => write!(fmt, "{:?} = {:?}", place, rv),
1681 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1682 Retag(ref kind, ref place) => write!(
1686 RetagKind::FnEntry => "[fn entry] ",
1687 RetagKind::TwoPhase => "[2phase] ",
1688 RetagKind::Raw => "[raw] ",
1689 RetagKind::Default => "",
1693 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1694 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1695 SetDiscriminant { ref place, variant_index } => {
1696 write!(fmt, "discriminant({:?}) = {:?}", place, variant_index)
1698 InlineAsm(ref asm) => {
1699 write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs)
1701 AscribeUserType(box(ref place, ref c_ty), ref variance) => {
1702 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1704 Nop => write!(fmt, "nop"),
1709 ///////////////////////////////////////////////////////////////////////////
1712 /// A path to a value; something that can be evaluated without
1713 /// changing or disturbing program state.
1715 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1717 pub struct Place<'tcx> {
1718 pub base: PlaceBase<'tcx>,
1720 /// projection out of a place (access a field, deref a pointer, etc)
1721 pub projection: Box<[PlaceElem<'tcx>]>,
1725 Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1727 pub enum PlaceBase<'tcx> {
1731 /// static or static mut variable
1732 Static(Box<Static<'tcx>>),
1735 /// We store the normalized type to avoid requiring normalization when reading MIR
1736 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1737 pub struct Static<'tcx> {
1739 pub kind: StaticKind<'tcx>,
1740 /// The `DefId` of the item this static was declared in. For promoted values, usually, this is
1741 /// the same as the `DefId` of the `mir::Body` containing the `Place` this promoted appears in.
1742 /// However, after inlining, that might no longer be the case as inlined `Place`s are copied
1743 /// into the calling frame.
1748 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable,
1750 pub enum StaticKind<'tcx> {
1751 /// Promoted references consist of an id (`Promoted`) and the substs necessary to monomorphize
1752 /// it. Usually, these substs are just the identity substs for the item. However, the inliner
1753 /// will adjust these substs when it inlines a function based on the substs at the callsite.
1754 Promoted(Promoted, SubstsRef<'tcx>),
1758 impl_stable_hash_for!(struct Static<'tcx> {
1765 Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable,
1767 pub enum ProjectionElem<V, T> {
1772 /// These indices are generated by slice patterns. Easiest to explain
1776 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1777 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1778 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1779 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1782 /// index or -index (in Python terms), depending on from_end
1784 /// thing being indexed must be at least this long
1786 /// counting backwards from end?
1790 /// These indices are generated by slice patterns.
1792 /// slice[from:-to] in Python terms.
1798 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1799 /// this for ADTs with more than one variant. It may be better to
1800 /// just introduce it always, or always for enums.
1802 /// The included Symbol is the name of the variant, used for printing MIR.
1803 Downcast(Option<Symbol>, VariantIdx),
1806 impl<V, T> ProjectionElem<V, T> {
1807 /// Returns `true` if the target of this projection may refer to a different region of memory
1809 fn is_indirect(&self) -> bool {
1811 Self::Deref => true,
1815 | Self::ConstantIndex { .. }
1816 | Self::Subslice { .. }
1817 | Self::Downcast(_, _)
1823 /// Alias for projections as they appear in places, where the base is a place
1824 /// and the index is a local.
1825 pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
1827 impl<'tcx> Copy for PlaceElem<'tcx> { }
1829 // At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
1830 #[cfg(target_arch = "x86_64")]
1831 static_assert_size!(PlaceElem<'_>, 16);
1833 /// Alias for projections as they appear in `UserTypeProjection`, where we
1834 /// need neither the `V` parameter for `Index` nor the `T` for `Field`.
1835 pub type ProjectionKind = ProjectionElem<(), ()>;
1837 rustc_index::newtype_index! {
1840 DEBUG_FORMAT = "field[{}]"
1844 #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
1845 pub struct PlaceRef<'a, 'tcx> {
1846 pub base: &'a PlaceBase<'tcx>,
1847 pub projection: &'a [PlaceElem<'tcx>],
1850 impl<'tcx> Place<'tcx> {
1851 // FIXME change this back to a const when projection is a shared slice.
1853 // pub const RETURN_PLACE: Place<'tcx> = Place {
1854 // base: PlaceBase::Local(RETURN_PLACE),
1857 pub fn return_place() -> Place<'tcx> {
1859 base: PlaceBase::Local(RETURN_PLACE),
1860 projection: Box::new([]),
1864 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
1865 self.elem(ProjectionElem::Field(f, ty))
1868 pub fn deref(self) -> Place<'tcx> {
1869 self.elem(ProjectionElem::Deref)
1872 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
1873 self.elem(ProjectionElem::Downcast(
1874 Some(adt_def.variants[variant_index].ident.name),
1879 pub fn downcast_unnamed(self, variant_index: VariantIdx) -> Place<'tcx> {
1880 self.elem(ProjectionElem::Downcast(None, variant_index))
1883 pub fn index(self, index: Local) -> Place<'tcx> {
1884 self.elem(ProjectionElem::Index(index))
1887 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
1888 // FIXME(spastorino): revisit this again once projection is not a Box<[T]> anymore
1889 let mut projection = self.projection.into_vec();
1890 projection.push(elem);
1894 projection: projection.into_boxed_slice(),
1898 /// Returns `true` if this `Place` contains a `Deref` projection.
1900 /// If `Place::is_indirect` returns false, the caller knows that the `Place` refers to the
1901 /// same region of memory as its base.
1902 pub fn is_indirect(&self) -> bool {
1903 self.projection.iter().any(|elem| elem.is_indirect())
1906 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1907 /// a single deref of a local.
1909 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1910 pub fn local_or_deref_local(&self) -> Option<Local> {
1913 base: PlaceBase::Local(local),
1917 base: PlaceBase::Local(local),
1918 projection: box [ProjectionElem::Deref],
1924 /// If this place represents a local variable like `_X` with no
1925 /// projections, return `Some(_X)`.
1926 pub fn as_local(&self) -> Option<Local> {
1928 Place { projection: box [], base: PlaceBase::Local(l) } => Some(*l),
1933 pub fn as_ref(&self) -> PlaceRef<'_, 'tcx> {
1936 projection: &self.projection,
1941 impl From<Local> for Place<'_> {
1942 fn from(local: Local) -> Self {
1945 projection: Box::new([]),
1950 impl From<Local> for PlaceBase<'_> {
1951 fn from(local: Local) -> Self {
1952 PlaceBase::Local(local)
1956 impl<'a, 'tcx> PlaceRef<'a, 'tcx> {
1957 /// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
1958 /// a single deref of a local.
1960 // FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
1961 pub fn local_or_deref_local(&self) -> Option<Local> {
1964 base: PlaceBase::Local(local),
1968 base: PlaceBase::Local(local),
1969 projection: [ProjectionElem::Deref],
1976 impl Debug for Place<'_> {
1977 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1978 for elem in self.projection.iter().rev() {
1980 ProjectionElem::Downcast(_, _) | ProjectionElem::Field(_, _) => {
1981 write!(fmt, "(").unwrap();
1983 ProjectionElem::Deref => {
1984 write!(fmt, "(*").unwrap();
1986 ProjectionElem::Index(_)
1987 | ProjectionElem::ConstantIndex { .. }
1988 | ProjectionElem::Subslice { .. } => {}
1992 write!(fmt, "{:?}", self.base)?;
1994 for elem in self.projection.iter() {
1996 ProjectionElem::Downcast(Some(name), _index) => {
1997 write!(fmt, " as {})", name)?;
1999 ProjectionElem::Downcast(None, index) => {
2000 write!(fmt, " as variant#{:?})", index)?;
2002 ProjectionElem::Deref => {
2005 ProjectionElem::Field(field, ty) => {
2006 write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
2008 ProjectionElem::Index(ref index) => {
2009 write!(fmt, "[{:?}]", index)?;
2011 ProjectionElem::ConstantIndex { offset, min_length, from_end: false } => {
2012 write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
2014 ProjectionElem::ConstantIndex { offset, min_length, from_end: true } => {
2015 write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
2017 ProjectionElem::Subslice { from, to } if *to == 0 => {
2018 write!(fmt, "[{:?}:]", from)?;
2020 ProjectionElem::Subslice { from, to } if *from == 0 => {
2021 write!(fmt, "[:-{:?}]", to)?;
2023 ProjectionElem::Subslice { from, to } => {
2024 write!(fmt, "[{:?}:-{:?}]", from, to)?;
2033 impl Debug for PlaceBase<'_> {
2034 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2036 PlaceBase::Local(id) => write!(fmt, "{:?}", id),
2037 PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static, def_id }) => {
2038 write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.def_path_str(def_id)), ty)
2040 PlaceBase::Static(box self::Static {
2041 ty, kind: StaticKind::Promoted(promoted, _), def_id: _
2043 write!(fmt, "({:?}: {:?})", promoted, ty)
2049 ///////////////////////////////////////////////////////////////////////////
2052 rustc_index::newtype_index! {
2053 pub struct SourceScope {
2055 DEBUG_FORMAT = "scope[{}]",
2056 const OUTERMOST_SOURCE_SCOPE = 0,
2060 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2061 pub struct SourceScopeData {
2063 pub parent_scope: Option<SourceScope>,
2066 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2067 pub struct SourceScopeLocalData {
2068 /// An `HirId` with lint levels equivalent to this scope's lint levels.
2069 pub lint_root: hir::HirId,
2070 /// The unsafe block that contains this node.
2074 ///////////////////////////////////////////////////////////////////////////
2077 /// These are values that can appear inside an rvalue. They are intentionally
2078 /// limited to prevent rvalues from being nested in one another.
2079 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
2080 pub enum Operand<'tcx> {
2081 /// Copy: The value must be available for use afterwards.
2083 /// This implies that the type of the place must be `Copy`; this is true
2084 /// by construction during build, but also checked by the MIR type checker.
2087 /// Move: The value (including old borrows of it) will not be used again.
2089 /// Safe for values of all types (modulo future developments towards `?Move`).
2090 /// Correct usage patterns are enforced by the borrow checker for safe code.
2091 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2094 /// Synthesizes a constant value.
2095 Constant(Box<Constant<'tcx>>),
2098 impl<'tcx> Debug for Operand<'tcx> {
2099 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2100 use self::Operand::*;
2102 Constant(ref a) => write!(fmt, "{:?}", a),
2103 Copy(ref place) => write!(fmt, "{:?}", place),
2104 Move(ref place) => write!(fmt, "move {:?}", place),
2109 impl<'tcx> Operand<'tcx> {
2110 /// Convenience helper to make a constant that refers to the fn
2111 /// with given `DefId` and substs. Since this is used to synthesize
2112 /// MIR, assumes `user_ty` is None.
2113 pub fn function_handle(
2116 substs: SubstsRef<'tcx>,
2119 let ty = tcx.type_of(def_id).subst(tcx, substs);
2120 Operand::Constant(box Constant {
2123 literal: ty::Const::zero_sized(tcx, ty),
2127 pub fn to_copy(&self) -> Self {
2129 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2130 Operand::Move(ref place) => Operand::Copy(place.clone()),
2135 ///////////////////////////////////////////////////////////////////////////
2138 #[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
2139 pub enum Rvalue<'tcx> {
2140 /// x (either a move or copy, depending on type of x)
2144 Repeat(Operand<'tcx>, u64),
2147 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2149 /// length of a [X] or [X;n] value
2152 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2154 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2155 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2157 NullaryOp(NullOp, Ty<'tcx>),
2158 UnaryOp(UnOp, Operand<'tcx>),
2160 /// Read the discriminant of an ADT.
2162 /// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
2163 /// be defined to return, say, a 0) if ADT is not an enum.
2164 Discriminant(Place<'tcx>),
2166 /// Creates an aggregate value, like a tuple or struct. This is
2167 /// only needed because we want to distinguish `dest = Foo { x:
2168 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2169 /// that `Foo` has a destructor. These rvalues can be optimized
2170 /// away after type-checking and before lowering.
2171 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2174 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2177 Pointer(PointerCast),
2180 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2181 pub enum AggregateKind<'tcx> {
2182 /// The type is of the element
2186 /// The second field is the variant index. It's equal to 0 for struct
2187 /// and union expressions. The fourth field is
2188 /// active field number and is present only for union expressions
2189 /// -- e.g., for a union expression `SomeUnion { c: .. }`, the
2190 /// active field index would identity the field `c`
2191 Adt(&'tcx AdtDef, VariantIdx, SubstsRef<'tcx>, Option<UserTypeAnnotationIndex>, Option<usize>),
2193 Closure(DefId, SubstsRef<'tcx>),
2194 Generator(DefId, SubstsRef<'tcx>, hir::GeneratorMovability),
2197 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2199 /// The `+` operator (addition)
2201 /// The `-` operator (subtraction)
2203 /// The `*` operator (multiplication)
2205 /// The `/` operator (division)
2207 /// The `%` operator (modulus)
2209 /// The `^` operator (bitwise xor)
2211 /// The `&` operator (bitwise and)
2213 /// The `|` operator (bitwise or)
2215 /// The `<<` operator (shift left)
2217 /// The `>>` operator (shift right)
2219 /// The `==` operator (equality)
2221 /// The `<` operator (less than)
2223 /// The `<=` operator (less than or equal to)
2225 /// The `!=` operator (not equal to)
2227 /// The `>=` operator (greater than or equal to)
2229 /// The `>` operator (greater than)
2231 /// The `ptr.offset` operator
2236 pub fn is_checkable(self) -> bool {
2239 Add | Sub | Mul | Shl | Shr => true,
2245 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2247 /// Returns the size of a value of that type
2249 /// Creates a new uninitialized box for a value of that type
2253 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
2255 /// The `!` operator for logical inversion
2257 /// The `-` operator for negation
2261 impl<'tcx> Debug for Rvalue<'tcx> {
2262 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2263 use self::Rvalue::*;
2266 Use(ref place) => write!(fmt, "{:?}", place),
2267 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2268 Len(ref a) => write!(fmt, "Len({:?})", a),
2269 Cast(ref kind, ref place, ref ty) => {
2270 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2272 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2273 CheckedBinaryOp(ref op, ref a, ref b) => {
2274 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2276 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2277 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2278 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2279 Ref(region, borrow_kind, ref place) => {
2280 let kind_str = match borrow_kind {
2281 BorrowKind::Shared => "",
2282 BorrowKind::Shallow => "shallow ",
2283 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2286 // When printing regions, add trailing space if necessary.
2287 let print_region = ty::tls::with(|tcx| {
2288 tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
2290 let region = if print_region {
2291 let mut region = region.to_string();
2292 if region.len() > 0 {
2297 // Do not even print 'static
2300 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2303 Aggregate(ref kind, ref places) => {
2304 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2305 let mut tuple_fmt = fmt.debug_tuple("");
2306 for place in places {
2307 tuple_fmt.field(place);
2313 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2315 AggregateKind::Tuple => match places.len() {
2316 0 => write!(fmt, "()"),
2317 1 => write!(fmt, "({:?},)", places[0]),
2318 _ => fmt_tuple(fmt, places),
2321 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2322 let variant_def = &adt_def.variants[variant];
2325 ty::tls::with(|tcx| {
2326 let substs = tcx.lift(&substs).expect("could not lift for printing");
2327 FmtPrinter::new(tcx, f, Namespace::ValueNS)
2328 .print_def_path(variant_def.def_id, substs)?;
2332 match variant_def.ctor_kind {
2333 CtorKind::Const => Ok(()),
2334 CtorKind::Fn => fmt_tuple(fmt, places),
2335 CtorKind::Fictive => {
2336 let mut struct_fmt = fmt.debug_struct("");
2337 for (field, place) in variant_def.fields.iter().zip(places) {
2338 struct_fmt.field(&field.ident.as_str(), place);
2345 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2346 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2347 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2348 format!("[closure@{:?}]", hir_id)
2350 format!("[closure@{:?}]", tcx.hir().span(hir_id))
2352 let mut struct_fmt = fmt.debug_struct(&name);
2354 if let Some(upvars) = tcx.upvars(def_id) {
2355 for (&var_id, place) in upvars.keys().zip(places) {
2356 let var_name = tcx.hir().name(var_id);
2357 struct_fmt.field(&var_name.as_str(), place);
2363 write!(fmt, "[closure]")
2367 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2368 if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
2369 let name = format!("[generator@{:?}]", tcx.hir().span(hir_id));
2370 let mut struct_fmt = fmt.debug_struct(&name);
2372 if let Some(upvars) = tcx.upvars(def_id) {
2373 for (&var_id, place) in upvars.keys().zip(places) {
2374 let var_name = tcx.hir().name(var_id);
2375 struct_fmt.field(&var_name.as_str(), place);
2381 write!(fmt, "[generator]")
2390 ///////////////////////////////////////////////////////////////////////////
2393 /// Two constants are equal if they are the same constant. Note that
2394 /// this does not necessarily mean that they are "==" in Rust -- in
2395 /// particular one must be wary of `NaN`!
2397 #[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2398 pub struct Constant<'tcx> {
2401 /// Optional user-given type: for something like
2402 /// `collect::<Vec<_>>`, this would be present and would
2403 /// indicate that `Vec<_>` was explicitly specified.
2405 /// Needed for NLL to impose user-given type constraints.
2406 pub user_ty: Option<UserTypeAnnotationIndex>,
2408 pub literal: &'tcx ty::Const<'tcx>,
2411 /// A collection of projections into user types.
2413 /// They are projections because a binding can occur a part of a
2414 /// parent pattern that has been ascribed a type.
2416 /// Its a collection because there can be multiple type ascriptions on
2417 /// the path from the root of the pattern down to the binding itself.
2422 /// struct S<'a>((i32, &'a str), String);
2423 /// let S((_, w): (i32, &'static str), _): S = ...;
2424 /// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
2425 /// // --------------------------------- ^ (2)
2428 /// The highlights labelled `(1)` show the subpattern `(_, w)` being
2429 /// ascribed the type `(i32, &'static str)`.
2431 /// The highlights labelled `(2)` show the whole pattern being
2432 /// ascribed the type `S`.
2434 /// In this example, when we descend to `w`, we will have built up the
2435 /// following two projected types:
2437 /// * base: `S`, projection: `(base.0).1`
2438 /// * base: `(i32, &'static str)`, projection: `base.1`
2440 /// The first will lead to the constraint `w: &'1 str` (for some
2441 /// inferred region `'1`). The second will lead to the constraint `w:
2443 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2444 pub struct UserTypeProjections {
2445 pub(crate) contents: Vec<(UserTypeProjection, Span)>,
2448 BraceStructTypeFoldableImpl! {
2449 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjections {
2454 impl<'tcx> UserTypeProjections {
2455 pub fn none() -> Self {
2456 UserTypeProjections { contents: vec![] }
2459 pub fn from_projections(projs: impl Iterator<Item = (UserTypeProjection, Span)>) -> Self {
2460 UserTypeProjections { contents: projs.collect() }
2463 pub fn projections_and_spans(&self) -> impl Iterator<Item = &(UserTypeProjection, Span)> {
2464 self.contents.iter()
2467 pub fn projections(&self) -> impl Iterator<Item = &UserTypeProjection> {
2468 self.contents.iter().map(|&(ref user_type, _span)| user_type)
2471 pub fn push_projection(mut self, user_ty: &UserTypeProjection, span: Span) -> Self {
2472 self.contents.push((user_ty.clone(), span));
2478 mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection,
2480 self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
2484 pub fn index(self) -> Self {
2485 self.map_projections(|pat_ty_proj| pat_ty_proj.index())
2488 pub fn subslice(self, from: u32, to: u32) -> Self {
2489 self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
2492 pub fn deref(self) -> Self {
2493 self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
2496 pub fn leaf(self, field: Field) -> Self {
2497 self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
2500 pub fn variant(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx, field: Field) -> Self {
2501 self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
2505 /// Encodes the effect of a user-supplied type annotation on the
2506 /// subcomponents of a pattern. The effect is determined by applying the
2507 /// given list of proejctions to some underlying base type. Often,
2508 /// the projection element list `projs` is empty, in which case this
2509 /// directly encodes a type in `base`. But in the case of complex patterns with
2510 /// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
2511 /// in which case the `projs` vector is used.
2515 /// * `let x: T = ...` -- here, the `projs` vector is empty.
2517 /// * `let (x, _): T = ...` -- here, the `projs` vector would contain
2518 /// `field[0]` (aka `.0`), indicating that the type of `s` is
2519 /// determined by finding the type of the `.0` field from `T`.
2520 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2521 pub struct UserTypeProjection {
2522 pub base: UserTypeAnnotationIndex,
2523 pub projs: Vec<ProjectionKind>,
2526 impl Copy for ProjectionKind {}
2528 impl UserTypeProjection {
2529 pub(crate) fn index(mut self) -> Self {
2530 self.projs.push(ProjectionElem::Index(()));
2534 pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
2535 self.projs.push(ProjectionElem::Subslice { from, to });
2539 pub(crate) fn deref(mut self) -> Self {
2540 self.projs.push(ProjectionElem::Deref);
2544 pub(crate) fn leaf(mut self, field: Field) -> Self {
2545 self.projs.push(ProjectionElem::Field(field, ()));
2549 pub(crate) fn variant(
2551 adt_def: &'tcx AdtDef,
2552 variant_index: VariantIdx,
2555 self.projs.push(ProjectionElem::Downcast(
2556 Some(adt_def.variants[variant_index].ident.name),
2559 self.projs.push(ProjectionElem::Field(field, ()));
2564 CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
2566 impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
2567 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
2568 use crate::mir::ProjectionElem::*;
2570 let base = self.base.fold_with(folder);
2571 let projs: Vec<_> = self
2574 .map(|elem| match elem {
2576 Field(f, ()) => Field(f.clone(), ()),
2577 Index(()) => Index(()),
2578 elem => elem.clone(),
2582 UserTypeProjection { base, projs }
2585 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2586 self.base.visit_with(visitor)
2587 // Note: there's nothing in `self.proj` to visit.
2591 rustc_index::newtype_index! {
2592 pub struct Promoted {
2594 DEBUG_FORMAT = "promoted[{}]"
2598 impl<'tcx> Debug for Constant<'tcx> {
2599 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2600 write!(fmt, "{}", self)
2604 impl<'tcx> Display for Constant<'tcx> {
2605 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2606 write!(fmt, "const ")?;
2607 // FIXME make the default pretty printing of raw pointers more detailed. Here we output the
2608 // debug representation of raw pointers, so that the raw pointers in the mir dump output are
2609 // detailed and just not '{pointer}'.
2610 if let ty::RawPtr(_) = self.literal.ty.kind {
2611 write!(fmt, "{:?} : {}", self.literal.val, self.literal.ty)
2613 write!(fmt, "{}", self.literal)
2618 impl<'tcx> graph::DirectedGraph for Body<'tcx> {
2619 type Node = BasicBlock;
2622 impl<'tcx> graph::WithNumNodes for Body<'tcx> {
2623 fn num_nodes(&self) -> usize {
2624 self.basic_blocks.len()
2628 impl<'tcx> graph::WithStartNode for Body<'tcx> {
2629 fn start_node(&self) -> Self::Node {
2634 impl<'tcx> graph::WithPredecessors for Body<'tcx> {
2638 ) -> <Self as GraphPredecessors<'_>>::Iter {
2639 self.predecessors_for(node).clone().into_iter()
2643 impl<'tcx> graph::WithSuccessors for Body<'tcx> {
2647 ) -> <Self as GraphSuccessors<'_>>::Iter {
2648 self.basic_blocks[node].terminator().successors().cloned()
2652 impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
2653 type Item = BasicBlock;
2654 type Iter = IntoIter<BasicBlock>;
2657 impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
2658 type Item = BasicBlock;
2659 type Iter = iter::Cloned<Successors<'b>>;
2662 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
2663 pub struct Location {
2664 /// The block that the location is within.
2665 pub block: BasicBlock,
2667 /// The location is the position of the start of the statement; or, if
2668 /// `statement_index` equals the number of statements, then the start of the
2670 pub statement_index: usize,
2673 impl fmt::Debug for Location {
2674 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2675 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2680 pub const START: Location = Location { block: START_BLOCK, statement_index: 0 };
2682 /// Returns the location immediately after this one within the enclosing block.
2684 /// Note that if this location represents a terminator, then the
2685 /// resulting location would be out of bounds and invalid.
2686 pub fn successor_within_block(&self) -> Location {
2687 Location { block: self.block, statement_index: self.statement_index + 1 }
2690 /// Returns `true` if `other` is earlier in the control flow graph than `self`.
2691 pub fn is_predecessor_of<'tcx>(&self, other: Location, body: &Body<'tcx>) -> bool {
2692 // If we are in the same block as the other location and are an earlier statement
2693 // then we are a predecessor of `other`.
2694 if self.block == other.block && self.statement_index < other.statement_index {
2698 // If we're in another block, then we want to check that block is a predecessor of `other`.
2699 let mut queue: Vec<BasicBlock> = body.predecessors_for(other.block).clone();
2700 let mut visited = FxHashSet::default();
2702 while let Some(block) = queue.pop() {
2703 // If we haven't visited this block before, then make sure we visit it's predecessors.
2704 if visited.insert(block) {
2705 queue.append(&mut body.predecessors_for(block).clone());
2710 // If we found the block that `self` is in, then we are a predecessor of `other` (since
2711 // we found that block by looking at the predecessors of `other`).
2712 if self.block == block {
2720 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2721 if self.block == other.block {
2722 self.statement_index <= other.statement_index
2724 dominators.is_dominated_by(other.block, self.block)
2729 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2730 pub enum UnsafetyViolationKind {
2732 /// Permitted both in `const fn`s and regular `fn`s.
2734 ExternStatic(hir::HirId),
2735 BorrowPacked(hir::HirId),
2738 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2739 pub struct UnsafetyViolation {
2740 pub source_info: SourceInfo,
2741 pub description: InternedString,
2742 pub details: InternedString,
2743 pub kind: UnsafetyViolationKind,
2746 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
2747 pub struct UnsafetyCheckResult {
2748 /// Violations that are propagated *upwards* from this function.
2749 pub violations: Lrc<[UnsafetyViolation]>,
2750 /// `unsafe` blocks in this function, along with whether they are used. This is
2751 /// used for the "unused_unsafe" lint.
2752 pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
2755 rustc_index::newtype_index! {
2756 pub struct GeneratorSavedLocal {
2758 DEBUG_FORMAT = "_{}",
2762 /// The layout of generator state.
2763 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2764 pub struct GeneratorLayout<'tcx> {
2765 /// The type of every local stored inside the generator.
2766 pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
2768 /// Which of the above fields are in each variant. Note that one field may
2769 /// be stored in multiple variants.
2770 pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
2772 /// Which saved locals are storage-live at the same time. Locals that do not
2773 /// have conflicts with each other are allowed to overlap in the computed
2775 pub storage_conflicts: BitMatrix<GeneratorSavedLocal, GeneratorSavedLocal>,
2777 /// The names and scopes of all the stored generator locals.
2779 /// N.B., this is *strictly* a temporary hack for codegen
2780 /// debuginfo generation, and will be removed at some point.
2781 /// Do **NOT** use it for anything else, local information should not be
2782 /// in the MIR, please rely on local crate HIR or other side-channels.
2784 // FIXME(tmandry): see above.
2785 pub __local_debuginfo_codegen_only_do_not_use: IndexVec<GeneratorSavedLocal, LocalDecl<'tcx>>,
2788 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2789 pub struct BorrowCheckResult<'tcx> {
2790 pub closure_requirements: Option<ClosureRegionRequirements<'tcx>>,
2791 pub used_mut_upvars: SmallVec<[Field; 8]>,
2794 /// After we borrow check a closure, we are left with various
2795 /// requirements that we have inferred between the free regions that
2796 /// appear in the closure's signature or on its field types. These
2797 /// requirements are then verified and proved by the closure's
2798 /// creating function. This struct encodes those requirements.
2800 /// The requirements are listed as being between various
2801 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2802 /// vids refer to the free regions that appear in the closure (or
2803 /// generator's) type, in order of appearance. (This numbering is
2804 /// actually defined by the `UniversalRegions` struct in the NLL
2805 /// region checker. See for example
2806 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2807 /// regions in the closure's type "as if" they were erased, so their
2808 /// precise identity is not important, only their position.
2810 /// Example: If type check produces a closure with the closure substs:
2813 /// ClosureSubsts = [
2814 /// i8, // the "closure kind"
2815 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2816 /// &'a String, // some upvar
2820 /// here, there is one unique free region (`'a`) but it appears
2821 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2824 /// ClosureSubsts = [
2825 /// i8, // the "closure kind"
2826 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2827 /// &'2 String, // some upvar
2831 /// Now the code might impose a requirement like `'1: '2`. When an
2832 /// instance of the closure is created, the corresponding free regions
2833 /// can be extracted from its type and constrained to have the given
2834 /// outlives relationship.
2836 /// In some cases, we have to record outlives requirements between
2837 /// types and regions as well. In that case, if those types include
2838 /// any regions, those regions are recorded as `ReClosureBound`
2839 /// instances assigned one of these same indices. Those regions will
2840 /// be substituted away by the creator. We use `ReClosureBound` in
2841 /// that case because the regions must be allocated in the global
2842 /// `TyCtxt`, and hence we cannot use `ReVar` (which is what we use
2843 /// internally within the rest of the NLL code).
2844 #[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2845 pub struct ClosureRegionRequirements<'tcx> {
2846 /// The number of external regions defined on the closure. In our
2847 /// example above, it would be 3 -- one for `'static`, then `'1`
2848 /// and `'2`. This is just used for a sanity check later on, to
2849 /// make sure that the number of regions we see at the callsite
2851 pub num_external_vids: usize,
2853 /// Requirements between the various free regions defined in
2855 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'tcx>>,
2858 /// Indicates an outlives-constraint between a type or between two
2859 /// free regions declared on the closure.
2860 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2861 pub struct ClosureOutlivesRequirement<'tcx> {
2862 // This region or type ...
2863 pub subject: ClosureOutlivesSubject<'tcx>,
2865 // ... must outlive this one.
2866 pub outlived_free_region: ty::RegionVid,
2868 // If not, report an error here ...
2869 pub blame_span: Span,
2871 // ... due to this reason.
2872 pub category: ConstraintCategory,
2875 /// Outlives-constraints can be categorized to determine whether and why they
2876 /// are interesting (for error reporting). Order of variants indicates sort
2877 /// order of the category, thereby influencing diagnostic output.
2879 /// See also [rustc_mir::borrow_check::nll::constraints].
2893 pub enum ConstraintCategory {
2901 /// A constraint that came from checking the body of a closure.
2903 /// We try to get the category that the closure used when reporting this.
2911 /// A "boring" constraint (caused by the given location) is one that
2912 /// the user probably doesn't want to see described in diagnostics,
2913 /// because it is kind of an artifact of the type system setup.
2914 /// Example: `x = Foo { field: y }` technically creates
2915 /// intermediate regions representing the "type of `Foo { field: y
2916 /// }`", and data flows from `y` into those variables, but they
2917 /// are not very interesting. The assignment into `x` on the other
2920 // Boring and applicable everywhere.
2923 /// A constraint that doesn't correspond to anything the user sees.
2927 /// The subject of a `ClosureOutlivesRequirement` -- that is, the thing
2928 /// that must outlive some region.
2929 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
2930 pub enum ClosureOutlivesSubject<'tcx> {
2931 /// Subject is a type, typically a type parameter, but could also
2932 /// be a projection. Indicates a requirement like `T: 'a` being
2933 /// passed to the caller, where the type here is `T`.
2935 /// The type here is guaranteed not to contain any free regions at
2939 /// Subject is a free region from the closure. Indicates a requirement
2940 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2941 Region(ty::RegionVid),
2945 * `TypeFoldable` implementations for MIR types
2948 CloneTypeFoldableAndLiftImpls! {
2958 SourceScopeLocalData,
2959 UserTypeAnnotationIndex,
2962 BraceStructTypeFoldableImpl! {
2963 impl<'tcx> TypeFoldable<'tcx> for Body<'tcx> {
2967 source_scope_local_data,
2972 user_type_annotations,
2974 __upvar_debuginfo_codegen_only_do_not_use,
2976 control_flow_destroyed,
2982 BraceStructTypeFoldableImpl! {
2983 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
2987 __local_debuginfo_codegen_only_do_not_use,
2991 BraceStructTypeFoldableImpl! {
2992 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
3005 BraceStructTypeFoldableImpl! {
3006 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
3013 BraceStructTypeFoldableImpl! {
3014 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
3019 EnumTypeFoldableImpl! {
3020 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
3021 (StatementKind::Assign)(a),
3022 (StatementKind::FakeRead)(cause, place),
3023 (StatementKind::SetDiscriminant) { place, variant_index },
3024 (StatementKind::StorageLive)(a),
3025 (StatementKind::StorageDead)(a),
3026 (StatementKind::InlineAsm)(a),
3027 (StatementKind::Retag)(kind, place),
3028 (StatementKind::AscribeUserType)(a, v),
3029 (StatementKind::Nop),
3033 BraceStructTypeFoldableImpl! {
3034 impl<'tcx> TypeFoldable<'tcx> for InlineAsm<'tcx> {
3041 EnumTypeFoldableImpl! {
3042 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
3043 (ClearCrossCrate::Clear),
3044 (ClearCrossCrate::Set)(a),
3045 } where T: TypeFoldable<'tcx>
3048 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
3049 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3050 use crate::mir::TerminatorKind::*;
3052 let kind = match self.kind {
3053 Goto { target } => Goto { target },
3054 SwitchInt { ref discr, switch_ty, ref values, ref targets } => SwitchInt {
3055 discr: discr.fold_with(folder),
3056 switch_ty: switch_ty.fold_with(folder),
3057 values: values.clone(),
3058 targets: targets.clone(),
3060 Drop { ref location, target, unwind } => {
3061 Drop { location: location.fold_with(folder), target, unwind }
3063 DropAndReplace { ref location, ref value, target, unwind } => DropAndReplace {
3064 location: location.fold_with(folder),
3065 value: value.fold_with(folder),
3069 Yield { ref value, resume, drop } => {
3070 Yield { value: value.fold_with(folder), resume: resume, drop: drop }
3072 Call { ref func, ref args, ref destination, cleanup, from_hir_call } => {
3074 destination.as_ref().map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
3077 func: func.fold_with(folder),
3078 args: args.fold_with(folder),
3084 Assert { ref cond, expected, ref msg, target, cleanup } => {
3086 let msg = match msg {
3087 BoundsCheck { ref len, ref index } =>
3089 len: len.fold_with(folder),
3090 index: index.fold_with(folder),
3092 Panic { .. } | Overflow(_) | OverflowNeg | DivisionByZero | RemainderByZero |
3093 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
3096 Assert { cond: cond.fold_with(folder), expected, msg, target, cleanup }
3098 GeneratorDrop => GeneratorDrop,
3102 Unreachable => Unreachable,
3103 FalseEdges { real_target, imaginary_target } => {
3104 FalseEdges { real_target, imaginary_target }
3106 FalseUnwind { real_target, unwind } => FalseUnwind { real_target, unwind },
3108 Terminator { source_info: self.source_info, kind }
3111 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3112 use crate::mir::TerminatorKind::*;
3115 SwitchInt { ref discr, switch_ty, .. } => {
3116 discr.visit_with(visitor) || switch_ty.visit_with(visitor)
3118 Drop { ref location, .. } => location.visit_with(visitor),
3119 DropAndReplace { ref location, ref value, .. } => {
3120 location.visit_with(visitor) || value.visit_with(visitor)
3122 Yield { ref value, .. } => value.visit_with(visitor),
3123 Call { ref func, ref args, ref destination, .. } => {
3124 let dest = if let Some((ref loc, _)) = *destination {
3125 loc.visit_with(visitor)
3129 dest || func.visit_with(visitor) || args.visit_with(visitor)
3131 Assert { ref cond, ref msg, .. } => {
3132 if cond.visit_with(visitor) {
3135 BoundsCheck { ref len, ref index } =>
3136 len.visit_with(visitor) || index.visit_with(visitor),
3137 Panic { .. } | Overflow(_) | OverflowNeg |
3138 DivisionByZero | RemainderByZero |
3139 GeneratorResumedAfterReturn | GeneratorResumedAfterPanic =>
3153 | FalseUnwind { .. } => false,
3158 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
3159 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3161 base: self.base.fold_with(folder),
3162 projection: self.projection.fold_with(folder),
3166 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3167 self.base.visit_with(visitor) || self.projection.visit_with(visitor)
3171 impl<'tcx> TypeFoldable<'tcx> for PlaceBase<'tcx> {
3172 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3174 PlaceBase::Local(local) => PlaceBase::Local(local.fold_with(folder)),
3175 PlaceBase::Static(static_) => PlaceBase::Static(static_.fold_with(folder)),
3179 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3181 PlaceBase::Local(local) => local.visit_with(visitor),
3182 PlaceBase::Static(static_) => (**static_).visit_with(visitor),
3187 impl<'tcx> TypeFoldable<'tcx> for Static<'tcx> {
3188 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3190 ty: self.ty.fold_with(folder),
3191 kind: self.kind.fold_with(folder),
3192 def_id: self.def_id,
3196 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3197 let Static { ty, kind, def_id: _ } = self;
3199 ty.visit_with(visitor) || kind.visit_with(visitor)
3203 impl<'tcx> TypeFoldable<'tcx> for StaticKind<'tcx> {
3204 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3206 StaticKind::Promoted(promoted, substs) =>
3207 StaticKind::Promoted(promoted.fold_with(folder), substs.fold_with(folder)),
3208 StaticKind::Static => StaticKind::Static
3212 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3214 StaticKind::Promoted(promoted, substs) =>
3215 promoted.visit_with(visitor) || substs.visit_with(visitor),
3216 StaticKind::Static => { false }
3221 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
3222 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3223 use crate::mir::Rvalue::*;
3225 Use(ref op) => Use(op.fold_with(folder)),
3226 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
3227 Ref(region, bk, ref place) => {
3228 Ref(region.fold_with(folder), bk, place.fold_with(folder))
3230 Len(ref place) => Len(place.fold_with(folder)),
3231 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
3232 BinaryOp(op, ref rhs, ref lhs) => {
3233 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3235 CheckedBinaryOp(op, ref rhs, ref lhs) => {
3236 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
3238 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
3239 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
3240 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
3241 Aggregate(ref kind, ref fields) => {
3242 let kind = box match **kind {
3243 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
3244 AggregateKind::Tuple => AggregateKind::Tuple,
3245 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
3248 substs.fold_with(folder),
3249 user_ty.fold_with(folder),
3252 AggregateKind::Closure(id, substs) => {
3253 AggregateKind::Closure(id, substs.fold_with(folder))
3255 AggregateKind::Generator(id, substs, movablity) => {
3256 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
3259 Aggregate(kind, fields.fold_with(folder))
3264 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3265 use crate::mir::Rvalue::*;
3267 Use(ref op) => op.visit_with(visitor),
3268 Repeat(ref op, _) => op.visit_with(visitor),
3269 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
3270 Len(ref place) => place.visit_with(visitor),
3271 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
3272 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
3273 rhs.visit_with(visitor) || lhs.visit_with(visitor)
3275 UnaryOp(_, ref val) => val.visit_with(visitor),
3276 Discriminant(ref place) => place.visit_with(visitor),
3277 NullaryOp(_, ty) => ty.visit_with(visitor),
3278 Aggregate(ref kind, ref fields) => {
3280 AggregateKind::Array(ty) => ty.visit_with(visitor),
3281 AggregateKind::Tuple => false,
3282 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3283 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3285 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3286 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3287 }) || fields.visit_with(visitor)
3293 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3294 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3296 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3297 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3298 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3302 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3304 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3305 Operand::Constant(ref c) => c.visit_with(visitor),
3310 impl<'tcx> TypeFoldable<'tcx> for PlaceElem<'tcx> {
3311 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3312 use crate::mir::ProjectionElem::*;
3316 Field(f, ty) => Field(*f, ty.fold_with(folder)),
3317 Index(v) => Index(v.fold_with(folder)),
3318 elem => elem.clone(),
3322 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3323 use crate::mir::ProjectionElem::*;
3326 Field(_, ty) => ty.visit_with(visitor),
3327 Index(v) => v.visit_with(visitor),
3333 impl<'tcx> TypeFoldable<'tcx> for Field {
3334 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3337 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3342 impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
3343 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3346 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3351 impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
3352 fn super_fold_with<F: TypeFolder<'tcx>>(&self, _: &mut F) -> Self {
3355 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3360 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3361 fn super_fold_with<F: TypeFolder<'tcx>>(&self, folder: &mut F) -> Self {
3363 span: self.span.clone(),
3364 user_ty: self.user_ty.fold_with(folder),
3365 literal: self.literal.fold_with(folder),
3368 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3369 self.literal.visit_with(visitor)