1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! MIR datatypes and passes. See the [rustc guide] for more info.
13 //! [rustc guide]: https://rust-lang-nursery.github.io/rustc-guide/mir/index.html
15 use hir::def::CtorKind;
16 use hir::def_id::DefId;
17 use hir::{self, HirId, InlineAsm};
19 use mir::interpret::{ConstValue, EvalErrorKind, Scalar};
20 use mir::visit::MirVisitable;
21 use rustc_apfloat::ieee::{Double, Single};
22 use rustc_apfloat::Float;
23 use rustc_data_structures::graph::dominators::{dominators, Dominators};
24 use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
25 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
26 use rustc_data_structures::sync::Lrc;
27 use rustc_data_structures::sync::MappedReadGuard;
28 use rustc_serialize as serialize;
29 use smallvec::SmallVec;
31 use std::fmt::{self, Debug, Formatter, Write};
32 use std::ops::{Index, IndexMut};
34 use std::vec::IntoIter;
35 use std::{iter, mem, option, u32};
36 use syntax::ast::{self, Name};
37 use syntax::symbol::InternedString;
38 use syntax_pos::{Span, DUMMY_SP};
39 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
40 use ty::subst::{Subst, Substs};
41 use ty::{self, AdtDef, CanonicalTy, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt};
44 pub use mir::interpret::AssertMessage;
54 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
56 pub trait HasLocalDecls<'tcx> {
57 fn local_decls(&self) -> &LocalDecls<'tcx>;
60 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
61 fn local_decls(&self) -> &LocalDecls<'tcx> {
66 impl<'tcx> HasLocalDecls<'tcx> for Mir<'tcx> {
67 fn local_decls(&self) -> &LocalDecls<'tcx> {
72 /// Lowered representation of a single function.
73 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
74 pub struct Mir<'tcx> {
75 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
76 /// that indexes into this vector.
77 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
79 /// List of source scopes; these are referenced by statements
80 /// and used for debuginfo. Indexed by a `SourceScope`.
81 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
83 /// Crate-local information for each source scope, that can't (and
84 /// needn't) be tracked across crates.
85 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
87 /// Rvalues promoted from this function, such as borrows of constants.
88 /// Each of them is the Mir of a constant with the fn's type parameters
89 /// in scope, but a separate set of locals.
90 pub promoted: IndexVec<Promoted, Mir<'tcx>>,
92 /// Yield type of the function, if it is a generator.
93 pub yield_ty: Option<Ty<'tcx>>,
95 /// Generator drop glue
96 pub generator_drop: Option<Box<Mir<'tcx>>>,
98 /// The layout of a generator. Produced by the state transformation.
99 pub generator_layout: Option<GeneratorLayout<'tcx>>,
101 /// Declarations of locals.
103 /// The first local is the return value pointer, followed by `arg_count`
104 /// locals for the function arguments, followed by any user-declared
105 /// variables and temporaries.
106 pub local_decls: LocalDecls<'tcx>,
108 /// Number of arguments this function takes.
110 /// Starting at local 1, `arg_count` locals will be provided by the caller
111 /// and can be assumed to be initialized.
113 /// If this MIR was built for a constant, this will be 0.
114 pub arg_count: usize,
116 /// Names and capture modes of all the closure upvars, assuming
117 /// the first argument is either the closure or a reference to it.
118 pub upvar_decls: Vec<UpvarDecl>,
120 /// Mark an argument local (which must be a tuple) as getting passed as
121 /// its individual components at the LLVM level.
123 /// This is used for the "rust-call" ABI.
124 pub spread_arg: Option<Local>,
126 /// A span representing this MIR, for error reporting
129 /// A cache for various calculations
133 impl<'tcx> Mir<'tcx> {
135 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
136 source_scopes: IndexVec<SourceScope, SourceScopeData>,
137 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
138 promoted: IndexVec<Promoted, Mir<'tcx>>,
139 yield_ty: Option<Ty<'tcx>>,
140 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
142 upvar_decls: Vec<UpvarDecl>,
145 // We need `arg_count` locals, and one for the return place
147 local_decls.len() >= arg_count + 1,
148 "expected at least {} locals, got {}",
156 source_scope_local_data,
159 generator_drop: None,
160 generator_layout: None,
166 cache: cache::Cache::new(),
171 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
176 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
177 self.cache.invalidate();
178 &mut self.basic_blocks
182 pub fn basic_blocks_and_local_decls_mut(
185 &mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
186 &mut LocalDecls<'tcx>,
188 self.cache.invalidate();
189 (&mut self.basic_blocks, &mut self.local_decls)
193 pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
194 self.cache.predecessors(self)
198 pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
199 MappedReadGuard::map(self.predecessors(), |p| &p[bb])
203 pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
204 let if_zero_locations = if loc.statement_index == 0 {
205 let predecessor_blocks = self.predecessors_for(loc.block);
206 let num_predecessor_blocks = predecessor_blocks.len();
208 (0..num_predecessor_blocks)
209 .map(move |i| predecessor_blocks[i])
210 .map(move |bb| self.terminator_loc(bb)),
216 let if_not_zero_locations = if loc.statement_index == 0 {
221 statement_index: loc.statement_index - 1,
228 .chain(if_not_zero_locations)
232 pub fn dominators(&self) -> Dominators<BasicBlock> {
237 pub fn local_kind(&self, local: Local) -> LocalKind {
238 let index = local.as_usize();
241 self.local_decls[local].mutability == Mutability::Mut,
242 "return place should be mutable"
245 LocalKind::ReturnPointer
246 } else if index < self.arg_count + 1 {
248 } else if self.local_decls[local].name.is_some() {
255 /// Returns an iterator over all temporaries.
257 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
258 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
259 let local = Local::new(index);
260 if self.local_decls[local].is_user_variable.is_some() {
268 /// Returns an iterator over all user-declared locals.
270 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
271 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
272 let local = Local::new(index);
273 if self.local_decls[local].is_user_variable.is_some() {
281 /// Returns an iterator over all user-declared mutable arguments and locals.
283 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
284 (1..self.local_decls.len()).filter_map(move |index| {
285 let local = Local::new(index);
286 let decl = &self.local_decls[local];
287 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
288 && decl.mutability == Mutability::Mut
297 /// Returns an iterator over all function arguments.
299 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
300 let arg_count = self.arg_count;
301 (1..arg_count + 1).map(Local::new)
304 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
305 /// locals that are neither arguments nor the return place).
307 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
308 let arg_count = self.arg_count;
309 let local_count = self.local_decls.len();
310 (arg_count + 1..local_count).map(Local::new)
313 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
314 /// invalidating statement indices in `Location`s.
315 pub fn make_statement_nop(&mut self, location: Location) {
316 let block = &mut self[location.block];
317 debug_assert!(location.statement_index < block.statements.len());
318 block.statements[location.statement_index].make_nop()
321 /// Returns the source info associated with `location`.
322 pub fn source_info(&self, location: Location) -> &SourceInfo {
323 let block = &self[location.block];
324 let stmts = &block.statements;
325 let idx = location.statement_index;
326 if idx < stmts.len() {
327 &stmts[idx].source_info
329 assert_eq!(idx, stmts.len());
330 &block.terminator().source_info
334 /// Check if `sub` is a sub scope of `sup`
335 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
337 match self.source_scopes[sub].parent_scope {
338 None => return false,
345 /// Return the return type, it always return first element from `local_decls` array
346 pub fn return_ty(&self) -> Ty<'tcx> {
347 self.local_decls[RETURN_PLACE].ty
350 /// Get the location of the terminator for the given block
351 pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
354 statement_index: self[bb].statements.len(),
359 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
362 /// Unsafe because of a PushUnsafeBlock
364 /// Unsafe because of an unsafe fn
366 /// Unsafe because of an `unsafe` block
367 ExplicitUnsafe(ast::NodeId),
370 impl_stable_hash_for!(struct Mir<'tcx> {
373 source_scope_local_data,
386 impl<'tcx> Index<BasicBlock> for Mir<'tcx> {
387 type Output = BasicBlockData<'tcx>;
390 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
391 &self.basic_blocks()[index]
395 impl<'tcx> IndexMut<BasicBlock> for Mir<'tcx> {
397 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
398 &mut self.basic_blocks_mut()[index]
402 #[derive(Copy, Clone, Debug)]
403 pub enum ClearCrossCrate<T> {
408 impl<T> ClearCrossCrate<T> {
409 pub fn assert_crate_local(self) -> T {
411 ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
412 ClearCrossCrate::Set(v) => v,
417 impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
418 impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
420 /// Grouped information about the source code origin of a MIR entity.
421 /// Intended to be inspected by diagnostics and debuginfo.
422 /// Most passes can work with it as a whole, within a single function.
423 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
424 pub struct SourceInfo {
425 /// Source span for the AST pertaining to this MIR entity.
428 /// The source scope, keeping track of which bindings can be
429 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
430 pub scope: SourceScope,
433 ///////////////////////////////////////////////////////////////////////////
434 // Mutability and borrow kinds
436 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
437 pub enum Mutability {
442 impl From<Mutability> for hir::Mutability {
443 fn from(m: Mutability) -> Self {
445 Mutability::Mut => hir::MutMutable,
446 Mutability::Not => hir::MutImmutable,
451 #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, RustcEncodable, RustcDecodable)]
452 pub enum BorrowKind {
453 /// Data must be immutable and is aliasable.
456 /// The immediately borrowed place must be immutable, but projections from
457 /// it don't need to be. For example, a shallow borrow of `a.b` doesn't
458 /// conflict with a mutable borrow of `a.b.c`.
460 /// This is used when lowering matches: when matching on a place we want to
461 /// ensure that place have the same value from the start of the match until
462 /// an arm is selected. This prevents this code from compiling:
464 /// let mut x = &Some(0);
467 /// Some(_) if { x = &None; false } => (),
471 /// This can't be a shared borrow because mutably borrowing (*x as Some).0
472 /// should not prevent `if let None = x { ... }`, for example, becase the
473 /// mutating `(*x as Some).0` can't affect the discriminant of `x`.
474 /// We can also report errors with this kind of borrow differently.
477 /// Data must be immutable but not aliasable. This kind of borrow
478 /// cannot currently be expressed by the user and is used only in
479 /// implicit closure bindings. It is needed when the closure is
480 /// borrowing or mutating a mutable referent, e.g.:
482 /// let x: &mut isize = ...;
483 /// let y = || *x += 5;
485 /// If we were to try to translate this closure into a more explicit
486 /// form, we'd encounter an error with the code as written:
488 /// struct Env { x: & &mut isize }
489 /// let x: &mut isize = ...;
490 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
491 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
493 /// This is then illegal because you cannot mutate an `&mut` found
494 /// in an aliasable location. To solve, you'd have to translate with
495 /// an `&mut` borrow:
497 /// struct Env { x: & &mut isize }
498 /// let x: &mut isize = ...;
499 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
500 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
502 /// Now the assignment to `**env.x` is legal, but creating a
503 /// mutable pointer to `x` is not because `x` is not mutable. We
504 /// could fix this by declaring `x` as `let mut x`. This is ok in
505 /// user code, if awkward, but extra weird for closures, since the
506 /// borrow is hidden.
508 /// So we introduce a "unique imm" borrow -- the referent is
509 /// immutable, but not aliasable. This solves the problem. For
510 /// simplicity, we don't give users the way to express this
511 /// borrow, it's just used when translating closures.
514 /// Data is mutable and not aliasable.
516 /// True if this borrow arose from method-call auto-ref
517 /// (i.e. `adjustment::Adjust::Borrow`)
518 allow_two_phase_borrow: bool,
523 pub fn allows_two_phase_borrow(&self) -> bool {
525 BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
526 BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
531 ///////////////////////////////////////////////////////////////////////////
532 // Variables and temps
536 DEBUG_FORMAT = "_{}",
537 const RETURN_PLACE = 0,
541 /// Classifies locals into categories. See `Mir::local_kind`.
542 #[derive(PartialEq, Eq, Debug)]
544 /// User-declared variable binding
546 /// Compiler-introduced temporary
548 /// Function argument
550 /// Location of function's return value
554 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
555 pub struct VarBindingForm<'tcx> {
556 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
557 pub binding_mode: ty::BindingMode,
558 /// If an explicit type was provided for this variable binding,
559 /// this holds the source Span of that type.
561 /// NOTE: If you want to change this to a `HirId`, be wary that
562 /// doing so breaks incremental compilation (as of this writing),
563 /// while a `Span` does not cause our tests to fail.
564 pub opt_ty_info: Option<Span>,
565 /// Place of the RHS of the =, or the subject of the `match` where this
566 /// variable is initialized. None in the case of `let PATTERN;`.
567 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
568 /// (a) the right-hand side isn't evaluated as a place expression.
569 /// (b) it gives a way to separate this case from the remaining cases
571 pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
572 /// Span of the pattern in which this variable was bound.
576 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
577 pub enum BindingForm<'tcx> {
578 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
579 Var(VarBindingForm<'tcx>),
580 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
581 ImplicitSelf(ImplicitSelfKind),
582 /// Reference used in a guard expression to ensure immutability.
586 /// Represents what type of implicit self a function has, if any.
587 #[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
588 pub enum ImplicitSelfKind {
589 /// Represents a `fn x(self);`.
591 /// Represents a `fn x(mut self);`.
593 /// Represents a `fn x(&self);`.
595 /// Represents a `fn x(&mut self);`.
597 /// Represents when a function does not have a self argument or
598 /// when a function has a `self: X` argument.
602 CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
604 impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
611 impl_stable_hash_for!(enum self::ImplicitSelfKind {
619 mod binding_form_impl {
620 use ich::StableHashingContext;
621 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
623 impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
624 fn hash_stable<W: StableHasherResult>(
626 hcx: &mut StableHashingContext<'a>,
627 hasher: &mut StableHasher<W>,
629 use super::BindingForm::*;
630 ::std::mem::discriminant(self).hash_stable(hcx, hasher);
633 Var(binding) => binding.hash_stable(hcx, hasher),
634 ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
643 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
644 /// argument, or the return place.
645 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
646 pub struct LocalDecl<'tcx> {
647 /// `let mut x` vs `let x`.
649 /// Temporaries and the return place are always mutable.
650 pub mutability: Mutability,
652 /// Some(binding_mode) if this corresponds to a user-declared local variable.
654 /// This is solely used for local diagnostics when generating
655 /// warnings/errors when compiling the current crate, and
656 /// therefore it need not be visible across crates. pnkfelix
657 /// currently hypothesized we *need* to wrap this in a
658 /// `ClearCrossCrate` as long as it carries as `HirId`.
659 pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
661 /// True if this is an internal local
663 /// These locals are not based on types in the source code and are only used
664 /// for a few desugarings at the moment.
666 /// The generator transformation will sanity check the locals which are live
667 /// across a suspension point against the type components of the generator
668 /// which type checking knows are live across a suspension point. We need to
669 /// flag drop flags to avoid triggering this check as they are introduced
672 /// Unsafety checking will also ignore dereferences of these locals,
673 /// so they can be used for raw pointers only used in a desugaring.
675 /// This should be sound because the drop flags are fully algebraic, and
676 /// therefore don't affect the OIBIT or outlives properties of the
680 /// Type of this local.
683 /// If the user manually ascribed a type to this variable,
684 /// e.g. via `let x: T`, then we carry that type here. The MIR
685 /// borrow checker needs this information since it can affect
686 /// region inference.
687 pub user_ty: Option<CanonicalTy<'tcx>>,
689 /// Name of the local, used in debuginfo and pretty-printing.
691 /// Note that function arguments can also have this set to `Some(_)`
692 /// to generate better debuginfo.
693 pub name: Option<Name>,
695 /// The *syntactic* (i.e. not visibility) source scope the local is defined
696 /// in. If the local was defined in a let-statement, this
697 /// is *within* the let-statement, rather than outside
700 /// This is needed because the visibility source scope of locals within
701 /// a let-statement is weird.
703 /// The reason is that we want the local to be *within* the let-statement
704 /// for lint purposes, but we want the local to be *after* the let-statement
705 /// for names-in-scope purposes.
707 /// That's it, if we have a let-statement like the one in this
711 /// fn foo(x: &str) {
712 /// #[allow(unused_mut)]
713 /// let mut x: u32 = { // <- one unused mut
714 /// let mut y: u32 = x.parse().unwrap();
721 /// Then, from a lint point of view, the declaration of `x: u32`
722 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
723 /// lint scopes are the same as the AST/HIR nesting.
725 /// However, from a name lookup point of view, the scopes look more like
726 /// as if the let-statements were `match` expressions:
729 /// fn foo(x: &str) {
731 /// match x.parse().unwrap() {
740 /// We care about the name-lookup scopes for debuginfo - if the
741 /// debuginfo instruction pointer is at the call to `x.parse()`, we
742 /// want `x` to refer to `x: &str`, but if it is at the call to
743 /// `drop(x)`, we want it to refer to `x: u32`.
745 /// To allow both uses to work, we need to have more than a single scope
746 /// for a local. We have the `source_info.scope` represent the
747 /// "syntactic" lint scope (with a variable being under its let
748 /// block) while the `visibility_scope` represents the "local variable"
749 /// scope (where the "rest" of a block is under all prior let-statements).
751 /// The end result looks like this:
755 /// │{ argument x: &str }
757 /// │ │{ #[allow(unused_mut)] } // this is actually split into 2 scopes
758 /// │ │ // in practice because I'm lazy.
760 /// │ │← x.source_info.scope
761 /// │ │← `x.parse().unwrap()`
763 /// │ │ │← y.source_info.scope
765 /// │ │ │{ let y: u32 }
767 /// │ │ │← y.visibility_scope
770 /// │ │{ let x: u32 }
771 /// │ │← x.visibility_scope
772 /// │ │← `drop(x)` // this accesses `x: u32`
774 pub source_info: SourceInfo,
776 /// Source scope within which the local is visible (for debuginfo)
777 /// (see `source_info` for more details).
778 pub visibility_scope: SourceScope,
781 impl<'tcx> LocalDecl<'tcx> {
782 /// Returns true only if local is a binding that can itself be
783 /// made mutable via the addition of the `mut` keyword, namely
784 /// something like the occurrences of `x` in:
785 /// - `fn foo(x: Type) { ... }`,
787 /// - or `match ... { C(x) => ... }`
788 pub fn can_be_made_mutable(&self) -> bool {
789 match self.is_user_variable {
790 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
791 binding_mode: ty::BindingMode::BindByValue(_),
797 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)))
804 /// Returns true if local is definitely not a `ref ident` or
805 /// `ref mut ident` binding. (Such bindings cannot be made into
806 /// mutable bindings, but the inverse does not necessarily hold).
807 pub fn is_nonref_binding(&self) -> bool {
808 match self.is_user_variable {
809 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
810 binding_mode: ty::BindingMode::BindByValue(_),
816 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
822 /// Create a new `LocalDecl` for a temporary.
824 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
825 Self::new_local(ty, Mutability::Mut, false, span)
828 /// Create a new immutable `LocalDecl` for a temporary.
830 pub fn new_immutable_temp(ty: Ty<'tcx>, span: Span) -> Self {
831 Self::new_local(ty, Mutability::Not, false, span)
834 /// Create a new `LocalDecl` for a internal temporary.
836 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
837 Self::new_local(ty, Mutability::Mut, true, span)
843 mutability: Mutability,
852 source_info: SourceInfo {
854 scope: OUTERMOST_SOURCE_SCOPE,
856 visibility_scope: OUTERMOST_SOURCE_SCOPE,
858 is_user_variable: None,
862 /// Builds a `LocalDecl` for the return place.
864 /// This must be inserted into the `local_decls` list as the first local.
866 pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
868 mutability: Mutability::Mut,
871 source_info: SourceInfo {
873 scope: OUTERMOST_SOURCE_SCOPE,
875 visibility_scope: OUTERMOST_SOURCE_SCOPE,
877 name: None, // FIXME maybe we do want some name here?
878 is_user_variable: None,
883 /// A closure capture, with its name and mode.
884 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
885 pub struct UpvarDecl {
886 pub debug_name: Name,
888 /// `HirId` of the captured variable
889 pub var_hir_id: ClearCrossCrate<HirId>,
891 /// If true, the capture is behind a reference.
894 pub mutability: Mutability,
897 ///////////////////////////////////////////////////////////////////////////
901 pub struct BasicBlock {
902 DEBUG_FORMAT = "bb{}",
903 const START_BLOCK = 0,
908 pub fn start_location(self) -> Location {
916 ///////////////////////////////////////////////////////////////////////////
917 // BasicBlockData and Terminator
919 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
920 pub struct BasicBlockData<'tcx> {
921 /// List of statements in this block.
922 pub statements: Vec<Statement<'tcx>>,
924 /// Terminator for this block.
926 /// NB. This should generally ONLY be `None` during construction.
927 /// Therefore, you should generally access it via the
928 /// `terminator()` or `terminator_mut()` methods. The only
929 /// exception is that certain passes, such as `simplify_cfg`, swap
930 /// out the terminator temporarily with `None` while they continue
931 /// to recurse over the set of basic blocks.
932 pub terminator: Option<Terminator<'tcx>>,
934 /// If true, this block lies on an unwind path. This is used
935 /// during codegen where distinct kinds of basic blocks may be
936 /// generated (particularly for MSVC cleanup). Unwind blocks must
937 /// only branch to other unwind blocks.
938 pub is_cleanup: bool,
941 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
942 pub struct Terminator<'tcx> {
943 pub source_info: SourceInfo,
944 pub kind: TerminatorKind<'tcx>,
947 #[derive(Clone, RustcEncodable, RustcDecodable)]
948 pub enum TerminatorKind<'tcx> {
949 /// block should have one successor in the graph; we jump there
950 Goto { target: BasicBlock },
952 /// operand evaluates to an integer; jump depending on its value
953 /// to one of the targets, and otherwise fallback to `otherwise`
955 /// discriminant value being tested
956 discr: Operand<'tcx>,
958 /// type of value being tested
961 /// Possible values. The locations to branch to in each case
962 /// are found in the corresponding indices from the `targets` vector.
963 values: Cow<'tcx, [u128]>,
965 /// Possible branch sites. The last element of this vector is used
966 /// for the otherwise branch, so targets.len() == values.len() + 1
968 // This invariant is quite non-obvious and also could be improved.
969 // One way to make this invariant is to have something like this instead:
971 // branches: Vec<(ConstInt, BasicBlock)>,
972 // otherwise: Option<BasicBlock> // exhaustive if None
974 // However we’ve decided to keep this as-is until we figure a case
975 // where some other approach seems to be strictly better than other.
976 targets: Vec<BasicBlock>,
979 /// Indicates that the landing pad is finished and unwinding should
980 /// continue. Emitted by build::scope::diverge_cleanup.
983 /// Indicates that the landing pad is finished and that the process
984 /// should abort. Used to prevent unwinding for foreign items.
987 /// Indicates a normal return. The return place should have
988 /// been filled in by now. This should occur at most once.
991 /// Indicates a terminator that can never be reached.
996 location: Place<'tcx>,
998 unwind: Option<BasicBlock>,
1001 /// Drop the Place and assign the new value over it. This ensures
1002 /// that the assignment to `P` occurs *even if* the destructor for
1003 /// place unwinds. Its semantics are best explained by the
1008 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
1016 /// Drop(P, goto BB1, unwind BB2)
1019 /// // P is now uninitialized
1023 /// // P is now uninitialized -- its dtor panicked
1028 location: Place<'tcx>,
1029 value: Operand<'tcx>,
1031 unwind: Option<BasicBlock>,
1034 /// Block ends with a call of a converging function
1036 /// The function that’s being called
1037 func: Operand<'tcx>,
1038 /// Arguments the function is called with.
1039 /// These are owned by the callee, which is free to modify them.
1040 /// This allows the memory occupied by "by-value" arguments to be
1041 /// reused across function calls without duplicating the contents.
1042 args: Vec<Operand<'tcx>>,
1043 /// Destination for the return value. If some, the call is converging.
1044 destination: Option<(Place<'tcx>, BasicBlock)>,
1045 /// Cleanups to be done if the call unwinds.
1046 cleanup: Option<BasicBlock>,
1047 /// Whether this is from a call in HIR, rather than from an overloaded
1048 /// operator. True for overloaded function call.
1049 from_hir_call: bool,
1052 /// Jump to the target if the condition has the expected value,
1053 /// otherwise panic with a message and a cleanup target.
1055 cond: Operand<'tcx>,
1057 msg: AssertMessage<'tcx>,
1059 cleanup: Option<BasicBlock>,
1064 /// The value to return
1065 value: Operand<'tcx>,
1066 /// Where to resume to
1068 /// Cleanup to be done if the generator is dropped at this suspend point
1069 drop: Option<BasicBlock>,
1072 /// Indicates the end of the dropping of a generator
1075 /// A block where control flow only ever takes one real path, but borrowck
1076 /// needs to be more conservative.
1078 /// The target normal control flow will take
1079 real_target: BasicBlock,
1080 /// The list of blocks control flow could conceptually take, but won't
1082 imaginary_targets: Vec<BasicBlock>,
1084 /// A terminator for blocks that only take one path in reality, but where we
1085 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
1086 /// This can arise in infinite loops with no function calls for example.
1088 /// The target normal control flow will take
1089 real_target: BasicBlock,
1090 /// The imaginary cleanup block link. This particular path will never be taken
1091 /// in practice, but in order to avoid fragility we want to always
1092 /// consider it in borrowck. We don't want to accept programs which
1093 /// pass borrowck only when panic=abort or some assertions are disabled
1094 /// due to release vs. debug mode builds. This needs to be an Option because
1095 /// of the remove_noop_landing_pads and no_landing_pads passes
1096 unwind: Option<BasicBlock>,
1100 pub type Successors<'a> =
1101 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1102 pub type SuccessorsMut<'a> =
1103 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1105 impl<'tcx> Terminator<'tcx> {
1106 pub fn successors(&self) -> Successors<'_> {
1107 self.kind.successors()
1110 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1111 self.kind.successors_mut()
1114 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1118 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1119 self.kind.unwind_mut()
1123 impl<'tcx> TerminatorKind<'tcx> {
1124 pub fn if_<'a, 'gcx>(
1125 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1126 cond: Operand<'tcx>,
1129 ) -> TerminatorKind<'tcx> {
1130 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1131 TerminatorKind::SwitchInt {
1133 switch_ty: tcx.types.bool,
1134 values: From::from(BOOL_SWITCH_FALSE),
1135 targets: vec![f, t],
1139 pub fn successors(&self) -> Successors<'_> {
1140 use self::TerminatorKind::*;
1151 } => None.into_iter().chain(&[]),
1152 Goto { target: ref t }
1155 cleanup: Some(ref t),
1159 destination: Some((_, ref t)),
1186 } => Some(t).into_iter().chain(&[]),
1188 destination: Some((_, ref t)),
1189 cleanup: Some(ref u),
1199 unwind: Some(ref u),
1204 unwind: Some(ref u),
1209 cleanup: Some(ref u),
1214 unwind: Some(ref u),
1215 } => Some(t).into_iter().chain(slice::from_ref(u)),
1216 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1219 ref imaginary_targets,
1220 } => Some(real_target).into_iter().chain(&imaginary_targets[..]),
1224 pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
1225 use self::TerminatorKind::*;
1236 } => None.into_iter().chain(&mut []),
1237 Goto { target: ref mut t }
1240 cleanup: Some(ref mut t),
1244 destination: Some((_, ref mut t)),
1269 real_target: ref mut t,
1271 } => Some(t).into_iter().chain(&mut []),
1273 destination: Some((_, ref mut t)),
1274 cleanup: Some(ref mut u),
1279 drop: Some(ref mut u),
1284 unwind: Some(ref mut u),
1289 unwind: Some(ref mut u),
1294 cleanup: Some(ref mut u),
1298 real_target: ref mut t,
1299 unwind: Some(ref mut u),
1300 } => Some(t).into_iter().chain(slice::from_mut(u)),
1303 } => None.into_iter().chain(&mut targets[..]),
1305 ref mut real_target,
1306 ref mut imaginary_targets,
1307 } => Some(real_target)
1309 .chain(&mut imaginary_targets[..]),
1313 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1315 TerminatorKind::Goto { .. }
1316 | TerminatorKind::Resume
1317 | TerminatorKind::Abort
1318 | TerminatorKind::Return
1319 | TerminatorKind::Unreachable
1320 | TerminatorKind::GeneratorDrop
1321 | TerminatorKind::Yield { .. }
1322 | TerminatorKind::SwitchInt { .. }
1323 | TerminatorKind::FalseEdges { .. } => None,
1324 TerminatorKind::Call {
1325 cleanup: ref unwind,
1328 | TerminatorKind::Assert {
1329 cleanup: ref unwind,
1332 | TerminatorKind::DropAndReplace { ref unwind, .. }
1333 | TerminatorKind::Drop { ref unwind, .. }
1334 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1338 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1340 TerminatorKind::Goto { .. }
1341 | TerminatorKind::Resume
1342 | TerminatorKind::Abort
1343 | TerminatorKind::Return
1344 | TerminatorKind::Unreachable
1345 | TerminatorKind::GeneratorDrop
1346 | TerminatorKind::Yield { .. }
1347 | TerminatorKind::SwitchInt { .. }
1348 | TerminatorKind::FalseEdges { .. } => None,
1349 TerminatorKind::Call {
1350 cleanup: ref mut unwind,
1353 | TerminatorKind::Assert {
1354 cleanup: ref mut unwind,
1357 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1358 | TerminatorKind::Drop { ref mut unwind, .. }
1359 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1364 impl<'tcx> BasicBlockData<'tcx> {
1365 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1373 /// Accessor for terminator.
1375 /// Terminator may not be None after construction of the basic block is complete. This accessor
1376 /// provides a convenience way to reach the terminator.
1377 pub fn terminator(&self) -> &Terminator<'tcx> {
1378 self.terminator.as_ref().expect("invalid terminator state")
1381 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1382 self.terminator.as_mut().expect("invalid terminator state")
1385 pub fn retain_statements<F>(&mut self, mut f: F)
1387 F: FnMut(&mut Statement<'_>) -> bool,
1389 for s in &mut self.statements {
1396 pub fn expand_statements<F, I>(&mut self, mut f: F)
1398 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1399 I: iter::TrustedLen<Item = Statement<'tcx>>,
1401 // Gather all the iterators we'll need to splice in, and their positions.
1402 let mut splices: Vec<(usize, I)> = vec![];
1403 let mut extra_stmts = 0;
1404 for (i, s) in self.statements.iter_mut().enumerate() {
1405 if let Some(mut new_stmts) = f(s) {
1406 if let Some(first) = new_stmts.next() {
1407 // We can already store the first new statement.
1410 // Save the other statements for optimized splicing.
1411 let remaining = new_stmts.size_hint().0;
1413 splices.push((i + 1 + extra_stmts, new_stmts));
1414 extra_stmts += remaining;
1422 // Splice in the new statements, from the end of the block.
1423 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1424 // where a range of elements ("gap") is left uninitialized, with
1425 // splicing adding new elements to the end of that gap and moving
1426 // existing elements from before the gap to the end of the gap.
1427 // For now, this is safe code, emulating a gap but initializing it.
1428 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1429 self.statements.resize(
1432 source_info: SourceInfo {
1434 scope: OUTERMOST_SOURCE_SCOPE,
1436 kind: StatementKind::Nop,
1439 for (splice_start, new_stmts) in splices.into_iter().rev() {
1440 let splice_end = splice_start + new_stmts.size_hint().0;
1441 while gap.end > splice_end {
1444 self.statements.swap(gap.start, gap.end);
1446 self.statements.splice(splice_start..splice_end, new_stmts);
1447 gap.end = splice_start;
1451 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1452 if index < self.statements.len() {
1453 &self.statements[index]
1460 impl<'tcx> Debug for TerminatorKind<'tcx> {
1461 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1462 self.fmt_head(fmt)?;
1463 let successor_count = self.successors().count();
1464 let labels = self.fmt_successor_labels();
1465 assert_eq!(successor_count, labels.len());
1467 match successor_count {
1470 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1473 write!(fmt, " -> [")?;
1474 for (i, target) in self.successors().enumerate() {
1478 write!(fmt, "{}: {:?}", labels[i], target)?;
1486 impl<'tcx> TerminatorKind<'tcx> {
1487 /// Write the "head" part of the terminator; that is, its name and the data it uses to pick the
1488 /// successor basic block, if any. The only information not included is the list of possible
1489 /// successors, which may be rendered differently between the text and the graphviz format.
1490 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1491 use self::TerminatorKind::*;
1493 Goto { .. } => write!(fmt, "goto"),
1495 discr: ref place, ..
1496 } => write!(fmt, "switchInt({:?})", place),
1497 Return => write!(fmt, "return"),
1498 GeneratorDrop => write!(fmt, "generator_drop"),
1499 Resume => write!(fmt, "resume"),
1500 Abort => write!(fmt, "abort"),
1501 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1502 Unreachable => write!(fmt, "unreachable"),
1503 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1508 } => write!(fmt, "replace({:?} <- {:?})", location, value),
1515 if let Some((ref destination, _)) = *destination {
1516 write!(fmt, "{:?} = ", destination)?;
1518 write!(fmt, "{:?}(", func)?;
1519 for (index, arg) in args.iter().enumerate() {
1523 write!(fmt, "{:?}", arg)?;
1533 write!(fmt, "assert(")?;
1537 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1539 FalseEdges { .. } => write!(fmt, "falseEdges"),
1540 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1544 /// Return the list of labels for the edges to the successor basic blocks.
1545 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1546 use self::TerminatorKind::*;
1548 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1549 Goto { .. } => vec!["".into()],
1555 let size = ty::tls::with(|tcx| {
1556 let param_env = ty::ParamEnv::empty();
1557 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1558 tcx.layout_of(param_env.and(switch_ty)).unwrap().size
1563 let mut s = String::new();
1565 val: ConstValue::Scalar(
1568 size: size.bytes() as u8,
1573 fmt_const_val(&mut s, &c).unwrap();
1575 }).chain(iter::once("otherwise".into()))
1579 destination: Some(_),
1582 } => vec!["return".into(), "unwind".into()],
1584 destination: Some(_),
1587 } => vec!["return".into()],
1592 } => vec!["unwind".into()],
1598 Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()],
1599 Yield { drop: None, .. } => vec!["resume".into()],
1600 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1601 vec!["return".into()]
1608 } => vec!["return".into(), "unwind".into()],
1609 Assert { cleanup: None, .. } => vec!["".into()],
1610 Assert { .. } => vec!["success".into(), "unwind".into()],
1612 ref imaginary_targets,
1615 let mut l = vec!["real".into()];
1616 l.resize(imaginary_targets.len() + 1, "imaginary".into());
1621 } => vec!["real".into(), "cleanup".into()],
1622 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1627 ///////////////////////////////////////////////////////////////////////////
1630 #[derive(Clone, RustcEncodable, RustcDecodable)]
1631 pub struct Statement<'tcx> {
1632 pub source_info: SourceInfo,
1633 pub kind: StatementKind<'tcx>,
1636 impl<'tcx> Statement<'tcx> {
1637 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1638 /// invalidating statement indices in `Location`s.
1639 pub fn make_nop(&mut self) {
1640 self.kind = StatementKind::Nop
1643 /// Changes a statement to a nop and returns the original statement.
1644 pub fn replace_nop(&mut self) -> Self {
1646 source_info: self.source_info,
1647 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1652 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1653 pub enum StatementKind<'tcx> {
1654 /// Write the RHS Rvalue to the LHS Place.
1655 Assign(Place<'tcx>, Box<Rvalue<'tcx>>),
1657 /// This represents all the reading that a pattern match may do
1658 /// (e.g. inspecting constants and discriminant values), and the
1659 /// kind of pattern it comes from. This is in order to adapt potential
1660 /// error messages to these specific patterns.
1661 FakeRead(FakeReadCause, Place<'tcx>),
1663 /// Write the discriminant for a variant to the enum Place.
1666 variant_index: usize,
1669 /// Start a live range for the storage of the local.
1672 /// End the current live range for the storage of the local.
1675 /// Execute a piece of inline Assembly.
1677 asm: Box<InlineAsm>,
1678 outputs: Box<[Place<'tcx>]>,
1679 inputs: Box<[Operand<'tcx>]>,
1682 /// Assert the given places to be valid inhabitants of their type. These statements are
1683 /// currently only interpreted by miri and only generated when "-Z mir-emit-validate" is passed.
1684 /// See <https://internals.rust-lang.org/t/types-as-contracts/5562/73> for more details.
1685 Validate(ValidationOp, Vec<ValidationOperand<'tcx, Place<'tcx>>>),
1687 /// Mark one terminating point of a region scope (i.e. static region).
1688 /// (The starting point(s) arise implicitly from borrows.)
1689 EndRegion(region::Scope),
1691 /// Encodes a user's type ascription. These need to be preserved
1692 /// intact so that NLL can respect them. For example:
1696 /// The effect of this annotation is to relate the type `T_y` of the place `y`
1697 /// to the user-given type `T`. The effect depends on the specified variance:
1699 /// - `Covariant` -- requires that `T_y <: T`
1700 /// - `Contravariant` -- requires that `T_y :> T`
1701 /// - `Invariant` -- requires that `T_y == T`
1702 /// - `Bivariant` -- no effect
1703 AscribeUserType(Place<'tcx>, ty::Variance, CanonicalTy<'tcx>),
1705 /// No-op. Useful for deleting instructions without affecting statement indices.
1709 /// The `FakeReadCause` describes the type of pattern why a `FakeRead` statement exists.
1710 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug)]
1711 pub enum FakeReadCause {
1712 /// Inject a fake read of the borrowed input at the start of each arm's
1713 /// pattern testing code.
1715 /// This should ensure that you cannot change the variant for an enum
1716 /// while you are in the midst of matching on it.
1719 /// `let x: !; match x {}` doesn't generate any read of x so we need to
1720 /// generate a read of x to check that it is initialized and safe.
1723 /// Officially, the semantics of
1725 /// `let pattern = <expr>;`
1727 /// is that `<expr>` is evaluated into a temporary and then this temporary is
1728 /// into the pattern.
1730 /// However, if we see the simple pattern `let var = <expr>`, we optimize this to
1731 /// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
1732 /// but in some cases it can affect the borrow checker, as in #53695.
1733 /// Therefore, we insert a "fake read" here to ensure that we get
1734 /// appropriate errors.
1738 /// The `ValidationOp` describes what happens with each of the operands of a
1739 /// `Validate` statement.
1740 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, PartialEq, Eq)]
1741 pub enum ValidationOp {
1742 /// Recursively traverse the place following the type and validate that all type
1743 /// invariants are maintained. Furthermore, acquire exclusive/read-only access to the
1744 /// memory reachable from the place.
1746 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1749 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1750 /// access *until* the given region ends. Then, access will be recovered.
1751 Suspend(region::Scope),
1754 impl Debug for ValidationOp {
1755 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1756 use self::ValidationOp::*;
1758 Acquire => write!(fmt, "Acquire"),
1759 Release => write!(fmt, "Release"),
1760 // (reuse lifetime rendering policy from ppaux.)
1761 Suspend(ref ce) => write!(fmt, "Suspend({})", ty::ReScope(*ce)),
1766 // This is generic so that it can be reused by miri
1767 #[derive(Clone, Hash, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1768 pub struct ValidationOperand<'tcx, T> {
1771 pub re: Option<region::Scope>,
1772 pub mutbl: hir::Mutability,
1775 impl<'tcx, T: Debug> Debug for ValidationOperand<'tcx, T> {
1776 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1777 write!(fmt, "{:?}: {:?}", self.place, self.ty)?;
1778 if let Some(ce) = self.re {
1779 // (reuse lifetime rendering policy from ppaux.)
1780 write!(fmt, "/{}", ty::ReScope(ce))?;
1782 if let hir::MutImmutable = self.mutbl {
1783 write!(fmt, " (imm)")?;
1789 impl<'tcx> Debug for Statement<'tcx> {
1790 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1791 use self::StatementKind::*;
1793 Assign(ref place, ref rv) => write!(fmt, "{:?} = {:?}", place, rv),
1794 FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
1795 // (reuse lifetime rendering policy from ppaux.)
1796 EndRegion(ref ce) => write!(fmt, "EndRegion({})", ty::ReScope(*ce)),
1797 Validate(ref op, ref places) => write!(fmt, "Validate({:?}, {:?})", op, places),
1798 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1799 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1803 } => write!(fmt, "discriminant({:?}) = {:?}", place, variant_index),
1808 } => write!(fmt, "asm!({:?} : {:?} : {:?})", asm, outputs, inputs),
1809 AscribeUserType(ref place, ref variance, ref c_ty) => {
1810 write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
1812 Nop => write!(fmt, "nop"),
1817 ///////////////////////////////////////////////////////////////////////////
1820 /// A path to a value; something that can be evaluated without
1821 /// changing or disturbing program state.
1822 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1823 pub enum Place<'tcx> {
1827 /// static or static mut variable
1828 Static(Box<Static<'tcx>>),
1830 /// Constant code promoted to an injected static
1831 Promoted(Box<(Promoted, Ty<'tcx>)>),
1833 /// projection out of a place (access a field, deref a pointer, etc)
1834 Projection(Box<PlaceProjection<'tcx>>),
1837 /// The def-id of a static, along with its normalized type (which is
1838 /// stored to avoid requiring normalization when reading MIR).
1839 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1840 pub struct Static<'tcx> {
1845 impl_stable_hash_for!(struct Static<'tcx> {
1850 /// The `Projection` data structure defines things of the form `B.x`
1851 /// or `*B` or `B[index]`. Note that it is parameterized because it is
1852 /// shared between `Constant` and `Place`. See the aliases
1853 /// `PlaceProjection` etc below.
1854 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1855 pub struct Projection<'tcx, B, V, T> {
1857 pub elem: ProjectionElem<'tcx, V, T>,
1860 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
1861 pub enum ProjectionElem<'tcx, V, T> {
1866 /// These indices are generated by slice patterns. Easiest to explain
1870 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1871 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1872 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1873 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1876 /// index or -index (in Python terms), depending on from_end
1878 /// thing being indexed must be at least this long
1880 /// counting backwards from end?
1884 /// These indices are generated by slice patterns.
1886 /// slice[from:-to] in Python terms.
1892 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1893 /// this for ADTs with more than one variant. It may be better to
1894 /// just introduce it always, or always for enums.
1895 Downcast(&'tcx AdtDef, usize),
1898 /// Alias for projections as they appear in places, where the base is a place
1899 /// and the index is a local.
1900 pub type PlaceProjection<'tcx> = Projection<'tcx, Place<'tcx>, Local, Ty<'tcx>>;
1902 /// Alias for projections as they appear in places, where the base is a place
1903 /// and the index is a local.
1904 pub type PlaceElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
1908 DEBUG_FORMAT = "field[{}]"
1912 impl<'tcx> Place<'tcx> {
1913 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
1914 self.elem(ProjectionElem::Field(f, ty))
1917 pub fn deref(self) -> Place<'tcx> {
1918 self.elem(ProjectionElem::Deref)
1921 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: usize) -> Place<'tcx> {
1922 self.elem(ProjectionElem::Downcast(adt_def, variant_index))
1925 pub fn index(self, index: Local) -> Place<'tcx> {
1926 self.elem(ProjectionElem::Index(index))
1929 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
1930 Place::Projection(Box::new(PlaceProjection { base: self, elem }))
1933 /// Find the innermost `Local` from this `Place`.
1934 pub fn local(&self) -> Option<Local> {
1936 Place::Local(local) |
1937 Place::Projection(box Projection {
1938 base: Place::Local(local),
1939 elem: ProjectionElem::Deref,
1946 impl<'tcx> Debug for Place<'tcx> {
1947 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
1951 Local(id) => write!(fmt, "{:?}", id),
1952 Static(box self::Static { def_id, ty }) => write!(
1955 ty::tls::with(|tcx| tcx.item_path_str(def_id)),
1958 Promoted(ref promoted) => write!(fmt, "({:?}: {:?})", promoted.0, promoted.1),
1959 Projection(ref data) => match data.elem {
1960 ProjectionElem::Downcast(ref adt_def, index) => {
1961 write!(fmt, "({:?} as {})", data.base, adt_def.variants[index].name)
1963 ProjectionElem::Deref => write!(fmt, "(*{:?})", data.base),
1964 ProjectionElem::Field(field, ty) => {
1965 write!(fmt, "({:?}.{:?}: {:?})", data.base, field.index(), ty)
1967 ProjectionElem::Index(ref index) => write!(fmt, "{:?}[{:?}]", data.base, index),
1968 ProjectionElem::ConstantIndex {
1972 } => write!(fmt, "{:?}[{:?} of {:?}]", data.base, offset, min_length),
1973 ProjectionElem::ConstantIndex {
1977 } => write!(fmt, "{:?}[-{:?} of {:?}]", data.base, offset, min_length),
1978 ProjectionElem::Subslice { from, to } if to == 0 => {
1979 write!(fmt, "{:?}[{:?}:]", data.base, from)
1981 ProjectionElem::Subslice { from, to } if from == 0 => {
1982 write!(fmt, "{:?}[:-{:?}]", data.base, to)
1984 ProjectionElem::Subslice { from, to } => {
1985 write!(fmt, "{:?}[{:?}:-{:?}]", data.base, from, to)
1992 ///////////////////////////////////////////////////////////////////////////
1996 pub struct SourceScope {
1997 DEBUG_FORMAT = "scope[{}]",
1998 const OUTERMOST_SOURCE_SCOPE = 0,
2002 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2003 pub struct SourceScopeData {
2005 pub parent_scope: Option<SourceScope>,
2008 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2009 pub struct SourceScopeLocalData {
2010 /// A NodeId with lint levels equivalent to this scope's lint levels.
2011 pub lint_root: ast::NodeId,
2012 /// The unsafe block that contains this node.
2016 ///////////////////////////////////////////////////////////////////////////
2019 /// These are values that can appear inside an rvalue (or an index
2020 /// place). They are intentionally limited to prevent rvalues from
2021 /// being nested in one another.
2022 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
2023 pub enum Operand<'tcx> {
2024 /// Copy: The value must be available for use afterwards.
2026 /// This implies that the type of the place must be `Copy`; this is true
2027 /// by construction during build, but also checked by the MIR type checker.
2030 /// Move: The value (including old borrows of it) will not be used again.
2032 /// Safe for values of all types (modulo future developments towards `?Move`).
2033 /// Correct usage patterns are enforced by the borrow checker for safe code.
2034 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
2037 /// Synthesizes a constant value.
2038 Constant(Box<Constant<'tcx>>),
2041 impl<'tcx> Debug for Operand<'tcx> {
2042 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2043 use self::Operand::*;
2045 Constant(ref a) => write!(fmt, "{:?}", a),
2046 Copy(ref place) => write!(fmt, "{:?}", place),
2047 Move(ref place) => write!(fmt, "move {:?}", place),
2052 impl<'tcx> Operand<'tcx> {
2053 /// Convenience helper to make a constant that refers to the fn
2054 /// with given def-id and substs. Since this is used to synthesize
2055 /// MIR, assumes `user_ty` is None.
2056 pub fn function_handle<'a>(
2057 tcx: TyCtxt<'a, 'tcx, 'tcx>,
2059 substs: &'tcx Substs<'tcx>,
2062 let ty = tcx.type_of(def_id).subst(tcx, substs);
2063 Operand::Constant(box Constant {
2067 literal: ty::Const::zero_sized(tcx, ty),
2071 pub fn to_copy(&self) -> Self {
2073 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
2074 Operand::Move(ref place) => Operand::Copy(place.clone()),
2079 ///////////////////////////////////////////////////////////////////////////
2082 #[derive(Clone, RustcEncodable, RustcDecodable)]
2083 pub enum Rvalue<'tcx> {
2084 /// x (either a move or copy, depending on type of x)
2088 Repeat(Operand<'tcx>, u64),
2091 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
2093 /// length of a [X] or [X;n] value
2096 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
2098 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2099 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
2101 NullaryOp(NullOp, Ty<'tcx>),
2102 UnaryOp(UnOp, Operand<'tcx>),
2104 /// Read the discriminant of an ADT.
2106 /// Undefined (i.e. no effort is made to make it defined, but there’s no reason why it cannot
2107 /// be defined to return, say, a 0) if ADT is not an enum.
2108 Discriminant(Place<'tcx>),
2110 /// Create an aggregate value, like a tuple or struct. This is
2111 /// only needed because we want to distinguish `dest = Foo { x:
2112 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
2113 /// that `Foo` has a destructor. These rvalues can be optimized
2114 /// away after type-checking and before lowering.
2115 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
2118 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2122 /// Convert unique, zero-sized type for a fn to fn()
2125 /// Convert non capturing closure to fn()
2128 /// Convert safe fn() to unsafe fn()
2131 /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
2132 /// codegen must figure out the details once full monomorphization
2133 /// is known. For example, this could be used to cast from a
2134 /// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<Trait>`
2135 /// (presuming `T: Trait`).
2139 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2140 pub enum AggregateKind<'tcx> {
2141 /// The type is of the element
2145 /// The second field is the variant index. It's equal to 0 for struct
2146 /// and union expressions. The fourth field is
2147 /// active field number and is present only for union expressions
2148 /// -- e.g. for a union expression `SomeUnion { c: .. }`, the
2149 /// active field index would identity the field `c`
2154 Option<CanonicalTy<'tcx>>,
2158 Closure(DefId, ClosureSubsts<'tcx>),
2159 Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
2162 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2164 /// The `+` operator (addition)
2166 /// The `-` operator (subtraction)
2168 /// The `*` operator (multiplication)
2170 /// The `/` operator (division)
2172 /// The `%` operator (modulus)
2174 /// The `^` operator (bitwise xor)
2176 /// The `&` operator (bitwise and)
2178 /// The `|` operator (bitwise or)
2180 /// The `<<` operator (shift left)
2182 /// The `>>` operator (shift right)
2184 /// The `==` operator (equality)
2186 /// The `<` operator (less than)
2188 /// The `<=` operator (less than or equal to)
2190 /// The `!=` operator (not equal to)
2192 /// The `>=` operator (greater than or equal to)
2194 /// The `>` operator (greater than)
2196 /// The `ptr.offset` operator
2201 pub fn is_checkable(self) -> bool {
2204 Add | Sub | Mul | Shl | Shr => true,
2210 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2212 /// Return the size of a value of that type
2214 /// Create a new uninitialized box for a value of that type
2218 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2220 /// The `!` operator for logical inversion
2222 /// The `-` operator for negation
2226 impl<'tcx> Debug for Rvalue<'tcx> {
2227 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2228 use self::Rvalue::*;
2231 Use(ref place) => write!(fmt, "{:?}", place),
2232 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2233 Len(ref a) => write!(fmt, "Len({:?})", a),
2234 Cast(ref kind, ref place, ref ty) => {
2235 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2237 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2238 CheckedBinaryOp(ref op, ref a, ref b) => {
2239 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2241 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2242 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2243 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2244 Ref(region, borrow_kind, ref place) => {
2245 let kind_str = match borrow_kind {
2246 BorrowKind::Shared => "",
2247 BorrowKind::Shallow => "shallow ",
2248 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2251 // When printing regions, add trailing space if necessary.
2252 let region = if ppaux::verbose() || ppaux::identify_regions() {
2253 let mut region = region.to_string();
2254 if region.len() > 0 {
2259 // Do not even print 'static
2262 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2265 Aggregate(ref kind, ref places) => {
2266 fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
2267 let mut tuple_fmt = fmt.debug_tuple("");
2268 for place in places {
2269 tuple_fmt.field(place);
2275 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2277 AggregateKind::Tuple => match places.len() {
2278 0 => write!(fmt, "()"),
2279 1 => write!(fmt, "({:?},)", places[0]),
2280 _ => fmt_tuple(fmt, places),
2283 AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
2284 let variant_def = &adt_def.variants[variant];
2286 ppaux::parameterized(fmt, substs, variant_def.did, &[])?;
2288 match variant_def.ctor_kind {
2289 CtorKind::Const => Ok(()),
2290 CtorKind::Fn => fmt_tuple(fmt, places),
2291 CtorKind::Fictive => {
2292 let mut struct_fmt = fmt.debug_struct("");
2293 for (field, place) in variant_def.fields.iter().zip(places) {
2294 struct_fmt.field(&field.ident.as_str(), place);
2301 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2302 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2303 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2304 format!("[closure@{:?}]", node_id)
2306 format!("[closure@{:?}]", tcx.hir.span(node_id))
2308 let mut struct_fmt = fmt.debug_struct(&name);
2310 tcx.with_freevars(node_id, |freevars| {
2311 for (freevar, place) in freevars.iter().zip(places) {
2312 let var_name = tcx.hir.name(freevar.var_id());
2313 struct_fmt.field(&var_name.as_str(), place);
2319 write!(fmt, "[closure]")
2323 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2324 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2325 let name = format!("[generator@{:?}]", tcx.hir.span(node_id));
2326 let mut struct_fmt = fmt.debug_struct(&name);
2328 tcx.with_freevars(node_id, |freevars| {
2329 for (freevar, place) in freevars.iter().zip(places) {
2330 let var_name = tcx.hir.name(freevar.var_id());
2331 struct_fmt.field(&var_name.as_str(), place);
2333 struct_fmt.field("$state", &places[freevars.len()]);
2334 for i in (freevars.len() + 1)..places.len() {
2336 .field(&format!("${}", i - freevars.len() - 1), &places[i]);
2342 write!(fmt, "[generator]")
2351 ///////////////////////////////////////////////////////////////////////////
2354 /// Two constants are equal if they are the same constant. Note that
2355 /// this does not necessarily mean that they are "==" in Rust -- in
2356 /// particular one must be wary of `NaN`!
2358 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2359 pub struct Constant<'tcx> {
2363 /// Optional user-given type: for something like
2364 /// `collect::<Vec<_>>`, this would be present and would
2365 /// indicate that `Vec<_>` was explicitly specified.
2367 /// Needed for NLL to impose user-given type constraints.
2368 pub user_ty: Option<CanonicalTy<'tcx>>,
2370 pub literal: &'tcx ty::Const<'tcx>,
2374 pub struct Promoted {
2375 DEBUG_FORMAT = "promoted[{}]"
2379 impl<'tcx> Debug for Constant<'tcx> {
2380 fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
2381 write!(fmt, "const ")?;
2382 fmt_const_val(fmt, self.literal)
2386 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
2387 pub fn fmt_const_val(f: &mut impl Write, const_val: &ty::Const<'_>) -> fmt::Result {
2389 let value = const_val.val;
2390 let ty = const_val.ty;
2391 // print some primitives
2392 if let ConstValue::Scalar(Scalar::Bits { bits, .. }) = value {
2394 Bool if bits == 0 => return write!(f, "false"),
2395 Bool if bits == 1 => return write!(f, "true"),
2396 Float(ast::FloatTy::F32) => return write!(f, "{}f32", Single::from_bits(bits)),
2397 Float(ast::FloatTy::F64) => return write!(f, "{}f64", Double::from_bits(bits)),
2398 Uint(ui) => return write!(f, "{:?}{}", bits, ui),
2400 let bit_width = ty::tls::with(|tcx| {
2401 let ty = tcx.lift_to_global(&ty).unwrap();
2402 tcx.layout_of(ty::ParamEnv::empty().and(ty))
2407 let shift = 128 - bit_width;
2408 return write!(f, "{:?}{}", ((bits as i128) << shift) >> shift, i);
2410 Char => return write!(f, "{:?}", ::std::char::from_u32(bits as u32).unwrap()),
2414 // print function definitons
2415 if let FnDef(did, _) = ty.sty {
2416 return write!(f, "{}", item_path_str(did));
2418 // print string literals
2419 if let ConstValue::ScalarPair(ptr, len) = value {
2420 if let Scalar::Ptr(ptr) = ptr {
2421 if let Scalar::Bits { bits: len, .. } = len {
2422 if let Ref(_, &ty::TyS { sty: Str, .. }, _) = ty.sty {
2423 return ty::tls::with(|tcx| {
2424 let alloc = tcx.alloc_map.lock().get(ptr.alloc_id);
2425 if let Some(interpret::AllocType::Memory(alloc)) = alloc {
2426 assert_eq!(len as usize as u128, len);
2428 &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
2429 let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
2430 write!(f, "{:?}", s)
2432 write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len)
2439 // just raw dump everything else
2440 write!(f, "{:?}:{}", value, ty)
2443 fn item_path_str(def_id: DefId) -> String {
2444 ty::tls::with(|tcx| tcx.item_path_str(def_id))
2447 impl<'tcx> graph::DirectedGraph for Mir<'tcx> {
2448 type Node = BasicBlock;
2451 impl<'tcx> graph::WithNumNodes for Mir<'tcx> {
2452 fn num_nodes(&self) -> usize {
2453 self.basic_blocks.len()
2457 impl<'tcx> graph::WithStartNode for Mir<'tcx> {
2458 fn start_node(&self) -> Self::Node {
2463 impl<'tcx> graph::WithPredecessors for Mir<'tcx> {
2464 fn predecessors<'graph>(
2467 ) -> <Self as GraphPredecessors<'graph>>::Iter {
2468 self.predecessors_for(node).clone().into_iter()
2472 impl<'tcx> graph::WithSuccessors for Mir<'tcx> {
2473 fn successors<'graph>(
2476 ) -> <Self as GraphSuccessors<'graph>>::Iter {
2477 self.basic_blocks[node].terminator().successors().cloned()
2481 impl<'a, 'b> graph::GraphPredecessors<'b> for Mir<'a> {
2482 type Item = BasicBlock;
2483 type Iter = IntoIter<BasicBlock>;
2486 impl<'a, 'b> graph::GraphSuccessors<'b> for Mir<'a> {
2487 type Item = BasicBlock;
2488 type Iter = iter::Cloned<Successors<'b>>;
2491 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
2492 pub struct Location {
2493 /// the location is within this block
2494 pub block: BasicBlock,
2496 /// the location is the start of the statement; or, if `statement_index`
2497 /// == num-statements, then the start of the terminator.
2498 pub statement_index: usize,
2501 impl fmt::Debug for Location {
2502 fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
2503 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2508 pub const START: Location = Location {
2513 /// Returns the location immediately after this one within the enclosing block.
2515 /// Note that if this location represents a terminator, then the
2516 /// resulting location would be out of bounds and invalid.
2517 pub fn successor_within_block(&self) -> Location {
2520 statement_index: self.statement_index + 1,
2524 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2525 if self.block == other.block {
2526 self.statement_index <= other.statement_index
2528 dominators.is_dominated_by(other.block, self.block)
2533 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2534 pub enum UnsafetyViolationKind {
2536 /// unsafety is not allowed at all in min const fn
2538 ExternStatic(ast::NodeId),
2539 BorrowPacked(ast::NodeId),
2542 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2543 pub struct UnsafetyViolation {
2544 pub source_info: SourceInfo,
2545 pub description: InternedString,
2546 pub details: InternedString,
2547 pub kind: UnsafetyViolationKind,
2550 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2551 pub struct UnsafetyCheckResult {
2552 /// Violations that are propagated *upwards* from this function
2553 pub violations: Lrc<[UnsafetyViolation]>,
2554 /// unsafe blocks in this function, along with whether they are used. This is
2555 /// used for the "unused_unsafe" lint.
2556 pub unsafe_blocks: Lrc<[(ast::NodeId, bool)]>,
2559 /// The layout of generator state
2560 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2561 pub struct GeneratorLayout<'tcx> {
2562 pub fields: Vec<LocalDecl<'tcx>>,
2565 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2566 pub struct BorrowCheckResult<'gcx> {
2567 pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
2568 pub used_mut_upvars: SmallVec<[Field; 8]>,
2571 /// After we borrow check a closure, we are left with various
2572 /// requirements that we have inferred between the free regions that
2573 /// appear in the closure's signature or on its field types. These
2574 /// requirements are then verified and proved by the closure's
2575 /// creating function. This struct encodes those requirements.
2577 /// The requirements are listed as being between various
2578 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2579 /// vids refer to the free regions that appear in the closure (or
2580 /// generator's) type, in order of appearance. (This numbering is
2581 /// actually defined by the `UniversalRegions` struct in the NLL
2582 /// region checker. See for example
2583 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2584 /// regions in the closure's type "as if" they were erased, so their
2585 /// precise identity is not important, only their position.
2587 /// Example: If type check produces a closure with the closure substs:
2590 /// ClosureSubsts = [
2591 /// i8, // the "closure kind"
2592 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2593 /// &'a String, // some upvar
2597 /// here, there is one unique free region (`'a`) but it appears
2598 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2601 /// ClosureSubsts = [
2602 /// i8, // the "closure kind"
2603 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2604 /// &'2 String, // some upvar
2608 /// Now the code might impose a requirement like `'1: '2`. When an
2609 /// instance of the closure is created, the corresponding free regions
2610 /// can be extracted from its type and constrained to have the given
2611 /// outlives relationship.
2613 /// In some cases, we have to record outlives requirements between
2614 /// types and regions as well. In that case, if those types include
2615 /// any regions, those regions are recorded as `ReClosureBound`
2616 /// instances assigned one of these same indices. Those regions will
2617 /// be substituted away by the creator. We use `ReClosureBound` in
2618 /// that case because the regions must be allocated in the global
2619 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
2620 /// internally within the rest of the NLL code).
2621 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2622 pub struct ClosureRegionRequirements<'gcx> {
2623 /// The number of external regions defined on the closure. In our
2624 /// example above, it would be 3 -- one for `'static`, then `'1`
2625 /// and `'2`. This is just used for a sanity check later on, to
2626 /// make sure that the number of regions we see at the callsite
2628 pub num_external_vids: usize,
2630 /// Requirements between the various free regions defined in
2632 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
2635 /// Indicates an outlives constraint between a type or between two
2636 /// free-regions declared on the closure.
2637 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2638 pub struct ClosureOutlivesRequirement<'tcx> {
2639 // This region or type ...
2640 pub subject: ClosureOutlivesSubject<'tcx>,
2642 // .. must outlive this one.
2643 pub outlived_free_region: ty::RegionVid,
2645 // If not, report an error here.
2646 pub blame_span: Span,
2649 /// The subject of a ClosureOutlivesRequirement -- that is, the thing
2650 /// that must outlive some region.
2651 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2652 pub enum ClosureOutlivesSubject<'tcx> {
2653 /// Subject is a type, typically a type parameter, but could also
2654 /// be a projection. Indicates a requirement like `T: 'a` being
2655 /// passed to the caller, where the type here is `T`.
2657 /// The type here is guaranteed not to contain any free regions at
2661 /// Subject is a free region from the closure. Indicates a requirement
2662 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2663 Region(ty::RegionVid),
2667 * TypeFoldable implementations for MIR types
2670 CloneTypeFoldableAndLiftImpls! {
2678 SourceScopeLocalData,
2681 BraceStructTypeFoldableImpl! {
2682 impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
2685 source_scope_local_data,
2699 BraceStructTypeFoldableImpl! {
2700 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
2705 BraceStructTypeFoldableImpl! {
2706 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
2718 BraceStructTypeFoldableImpl! {
2719 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
2726 BraceStructTypeFoldableImpl! {
2727 impl<'tcx> TypeFoldable<'tcx> for ValidationOperand<'tcx, Place<'tcx>> {
2728 place, ty, re, mutbl
2732 BraceStructTypeFoldableImpl! {
2733 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
2738 EnumTypeFoldableImpl! {
2739 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
2740 (StatementKind::Assign)(a, b),
2741 (StatementKind::FakeRead)(cause, place),
2742 (StatementKind::SetDiscriminant) { place, variant_index },
2743 (StatementKind::StorageLive)(a),
2744 (StatementKind::StorageDead)(a),
2745 (StatementKind::InlineAsm) { asm, outputs, inputs },
2746 (StatementKind::Validate)(a, b),
2747 (StatementKind::EndRegion)(a),
2748 (StatementKind::AscribeUserType)(a, v, b),
2749 (StatementKind::Nop),
2753 EnumTypeFoldableImpl! {
2754 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
2755 (ClearCrossCrate::Clear),
2756 (ClearCrossCrate::Set)(a),
2757 } where T: TypeFoldable<'tcx>
2760 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2761 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2762 use mir::TerminatorKind::*;
2764 let kind = match self.kind {
2765 Goto { target } => Goto { target: target },
2772 discr: discr.fold_with(folder),
2773 switch_ty: switch_ty.fold_with(folder),
2774 values: values.clone(),
2775 targets: targets.clone(),
2782 location: location.fold_with(folder),
2791 } => DropAndReplace {
2792 location: location.fold_with(folder),
2793 value: value.fold_with(folder),
2802 value: value.fold_with(folder),
2813 let dest = destination
2815 .map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2818 func: func.fold_with(folder),
2819 args: args.fold_with(folder),
2832 let msg = if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2833 EvalErrorKind::BoundsCheck {
2834 len: len.fold_with(folder),
2835 index: index.fold_with(folder),
2841 cond: cond.fold_with(folder),
2848 GeneratorDrop => GeneratorDrop,
2852 Unreachable => Unreachable,
2855 ref imaginary_targets,
2858 imaginary_targets: imaginary_targets.clone(),
2869 source_info: self.source_info,
2874 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2875 use mir::TerminatorKind::*;
2882 } => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
2883 Drop { ref location, .. } => location.visit_with(visitor),
2888 } => location.visit_with(visitor) || value.visit_with(visitor),
2889 Yield { ref value, .. } => value.visit_with(visitor),
2896 let dest = if let Some((ref loc, _)) = *destination {
2897 loc.visit_with(visitor)
2901 dest || func.visit_with(visitor) || args.visit_with(visitor)
2904 ref cond, ref msg, ..
2906 if cond.visit_with(visitor) {
2907 if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2908 len.visit_with(visitor) || index.visit_with(visitor)
2923 | FalseUnwind { .. } => false,
2928 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2929 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2931 &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
2936 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2937 if let &Place::Projection(ref p) = self {
2938 p.visit_with(visitor)
2945 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
2946 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2949 Use(ref op) => Use(op.fold_with(folder)),
2950 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
2951 Ref(region, bk, ref place) => {
2952 Ref(region.fold_with(folder), bk, place.fold_with(folder))
2954 Len(ref place) => Len(place.fold_with(folder)),
2955 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
2956 BinaryOp(op, ref rhs, ref lhs) => {
2957 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2959 CheckedBinaryOp(op, ref rhs, ref lhs) => {
2960 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2962 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
2963 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
2964 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
2965 Aggregate(ref kind, ref fields) => {
2966 let kind = box match **kind {
2967 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
2968 AggregateKind::Tuple => AggregateKind::Tuple,
2969 AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
2972 substs.fold_with(folder),
2973 user_ty.fold_with(folder),
2976 AggregateKind::Closure(id, substs) => {
2977 AggregateKind::Closure(id, substs.fold_with(folder))
2979 AggregateKind::Generator(id, substs, movablity) => {
2980 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
2983 Aggregate(kind, fields.fold_with(folder))
2988 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2991 Use(ref op) => op.visit_with(visitor),
2992 Repeat(ref op, _) => op.visit_with(visitor),
2993 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
2994 Len(ref place) => place.visit_with(visitor),
2995 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
2996 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
2997 rhs.visit_with(visitor) || lhs.visit_with(visitor)
2999 UnaryOp(_, ref val) => val.visit_with(visitor),
3000 Discriminant(ref place) => place.visit_with(visitor),
3001 NullaryOp(_, ty) => ty.visit_with(visitor),
3002 Aggregate(ref kind, ref fields) => {
3004 AggregateKind::Array(ty) => ty.visit_with(visitor),
3005 AggregateKind::Tuple => false,
3006 AggregateKind::Adt(_, _, substs, user_ty, _) => {
3007 substs.visit_with(visitor) || user_ty.visit_with(visitor)
3009 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
3010 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
3011 }) || fields.visit_with(visitor)
3017 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
3018 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3020 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
3021 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
3022 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
3026 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3028 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
3029 Operand::Constant(ref c) => c.visit_with(visitor),
3034 impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<'tcx, B, V, T>
3036 B: TypeFoldable<'tcx>,
3037 V: TypeFoldable<'tcx>,
3038 T: TypeFoldable<'tcx>,
3040 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3041 use mir::ProjectionElem::*;
3043 let base = self.base.fold_with(folder);
3044 let elem = match self.elem {
3046 Field(f, ref ty) => Field(f, ty.fold_with(folder)),
3047 Index(ref v) => Index(v.fold_with(folder)),
3048 ref elem => elem.clone(),
3051 Projection { base, elem }
3054 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
3055 use mir::ProjectionElem::*;
3057 self.base.visit_with(visitor) || match self.elem {
3058 Field(_, ref ty) => ty.visit_with(visitor),
3059 Index(ref v) => v.visit_with(visitor),
3065 impl<'tcx> TypeFoldable<'tcx> for Field {
3066 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
3069 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
3074 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
3075 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
3077 span: self.span.clone(),
3078 ty: self.ty.fold_with(folder),
3079 user_ty: self.user_ty.fold_with(folder),
3080 literal: self.literal.fold_with(folder),
3083 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
3084 self.ty.visit_with(visitor) || self.literal.visit_with(visitor)