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 graphviz
::IntoCow
;
16 use hir
::def
::CtorKind
;
17 use hir
::def_id
::DefId
;
18 use hir
::{self, HirId, InlineAsm}
;
20 use mir
::interpret
::{EvalErrorKind, Scalar, Value}
;
21 use mir
::visit
::MirVisitable
;
22 use rustc_apfloat
::ieee
::{Double, Single}
;
23 use rustc_apfloat
::Float
;
24 use rustc_data_structures
::graph
::dominators
::{dominators, Dominators}
;
25 use rustc_data_structures
::graph
::{self, GraphPredecessors, GraphSuccessors}
;
26 use rustc_data_structures
::indexed_vec
::{Idx, IndexVec}
;
27 use rustc_data_structures
::small_vec
::SmallVec
;
28 use rustc_data_structures
::sync
::Lrc
;
29 use rustc_data_structures
::sync
::ReadGuard
;
30 use rustc_serialize
as serialize
;
32 use std
::fmt
::{self, Debug, Formatter, Write}
;
33 use std
::ops
::{Index, IndexMut}
;
35 use std
::vec
::IntoIter
;
36 use std
::{iter, mem, option, u32}
;
37 use syntax
::ast
::{self, Name}
;
38 use syntax
::symbol
::InternedString
;
39 use syntax_pos
::{Span, DUMMY_SP}
;
40 use ty
::fold
::{TypeFoldable, TypeFolder, TypeVisitor}
;
41 use ty
::subst
::{Subst, Substs}
;
42 use ty
::{self, AdtDef, CanonicalTy, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt}
;
45 pub use mir
::interpret
::AssertMessage
;
55 type LocalDecls
<'tcx
> = IndexVec
<Local
, LocalDecl
<'tcx
>>;
57 pub trait HasLocalDecls
<'tcx
> {
58 fn local_decls(&self) -> &LocalDecls
<'tcx
>;
61 impl<'tcx
> HasLocalDecls
<'tcx
> for LocalDecls
<'tcx
> {
62 fn local_decls(&self) -> &LocalDecls
<'tcx
> {
67 impl<'tcx
> HasLocalDecls
<'tcx
> for Mir
<'tcx
> {
68 fn local_decls(&self) -> &LocalDecls
<'tcx
> {
73 /// Lowered representation of a single function.
74 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
75 pub struct Mir
<'tcx
> {
76 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
77 /// that indexes into this vector.
78 basic_blocks
: IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>>,
80 /// List of source scopes; these are referenced by statements
81 /// and used for debuginfo. Indexed by a `SourceScope`.
82 pub source_scopes
: IndexVec
<SourceScope
, SourceScopeData
>,
84 /// Crate-local information for each source scope, that can't (and
85 /// needn't) be tracked across crates.
86 pub source_scope_local_data
: ClearCrossCrate
<IndexVec
<SourceScope
, SourceScopeLocalData
>>,
88 /// Rvalues promoted from this function, such as borrows of constants.
89 /// Each of them is the Mir of a constant with the fn's type parameters
90 /// in scope, but a separate set of locals.
91 pub promoted
: IndexVec
<Promoted
, Mir
<'tcx
>>,
93 /// Yield type of the function, if it is a generator.
94 pub yield_ty
: Option
<Ty
<'tcx
>>,
96 /// Generator drop glue
97 pub generator_drop
: Option
<Box
<Mir
<'tcx
>>>,
99 /// The layout of a generator. Produced by the state transformation.
100 pub generator_layout
: Option
<GeneratorLayout
<'tcx
>>,
102 /// Declarations of locals.
104 /// The first local is the return value pointer, followed by `arg_count`
105 /// locals for the function arguments, followed by any user-declared
106 /// variables and temporaries.
107 pub local_decls
: LocalDecls
<'tcx
>,
109 /// Number of arguments this function takes.
111 /// Starting at local 1, `arg_count` locals will be provided by the caller
112 /// and can be assumed to be initialized.
114 /// If this MIR was built for a constant, this will be 0.
115 pub arg_count
: usize,
117 /// Names and capture modes of all the closure upvars, assuming
118 /// the first argument is either the closure or a reference to it.
119 pub upvar_decls
: Vec
<UpvarDecl
>,
121 /// Mark an argument local (which must be a tuple) as getting passed as
122 /// its individual components at the LLVM level.
124 /// This is used for the "rust-call" ABI.
125 pub spread_arg
: Option
<Local
>,
127 /// A span representing this MIR, for error reporting
130 /// A cache for various calculations
134 /// where execution begins
135 pub const START_BLOCK
: BasicBlock
= BasicBlock(0);
137 impl<'tcx
> Mir
<'tcx
> {
139 basic_blocks
: IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>>,
140 source_scopes
: IndexVec
<SourceScope
, SourceScopeData
>,
141 source_scope_local_data
: ClearCrossCrate
<IndexVec
<SourceScope
, SourceScopeLocalData
>>,
142 promoted
: IndexVec
<Promoted
, Mir
<'tcx
>>,
143 yield_ty
: Option
<Ty
<'tcx
>>,
144 local_decls
: IndexVec
<Local
, LocalDecl
<'tcx
>>,
146 upvar_decls
: Vec
<UpvarDecl
>,
149 // We need `arg_count` locals, and one for the return place
151 local_decls
.len() >= arg_count
+ 1,
152 "expected at least {} locals, got {}",
160 source_scope_local_data
,
163 generator_drop
: None
,
164 generator_layout
: None
,
170 cache
: cache
::Cache
::new(),
175 pub fn basic_blocks(&self) -> &IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>> {
180 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>> {
181 self.cache
.invalidate();
182 &mut self.basic_blocks
186 pub fn basic_blocks_and_local_decls_mut(
189 &mut IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>>,
190 &mut LocalDecls
<'tcx
>,
192 self.cache
.invalidate();
193 (&mut self.basic_blocks
, &mut self.local_decls
)
197 pub fn predecessors(&self) -> ReadGuard
<IndexVec
<BasicBlock
, Vec
<BasicBlock
>>> {
198 self.cache
.predecessors(self)
202 pub fn predecessors_for(&self, bb
: BasicBlock
) -> ReadGuard
<Vec
<BasicBlock
>> {
203 ReadGuard
::map(self.predecessors(), |p
| &p
[bb
])
207 pub fn dominators(&self) -> Dominators
<BasicBlock
> {
212 pub fn local_kind(&self, local
: Local
) -> LocalKind
{
213 let index
= local
.0 as usize;
216 self.local_decls
[local
].mutability
== Mutability
::Mut
,
217 "return place should be mutable"
220 LocalKind
::ReturnPointer
221 } else if index
< self.arg_count
+ 1 {
223 } else if self.local_decls
[local
].name
.is_some() {
227 self.local_decls
[local
].mutability
== Mutability
::Mut
,
228 "temp should be mutable"
235 /// Returns an iterator over all temporaries.
237 pub fn temps_iter
<'a
>(&'a
self) -> impl Iterator
<Item
= Local
> + 'a
{
238 (self.arg_count
+ 1..self.local_decls
.len()).filter_map(move |index
| {
239 let local
= Local
::new(index
);
240 if self.local_decls
[local
].is_user_variable
.is_some() {
248 /// Returns an iterator over all user-declared locals.
250 pub fn vars_iter
<'a
>(&'a
self) -> impl Iterator
<Item
= Local
> + 'a
{
251 (self.arg_count
+ 1..self.local_decls
.len()).filter_map(move |index
| {
252 let local
= Local
::new(index
);
253 if self.local_decls
[local
].is_user_variable
.is_some() {
261 /// Returns an iterator over all user-declared mutable arguments and locals.
263 pub fn mut_vars_and_args_iter
<'a
>(&'a
self) -> impl Iterator
<Item
= Local
> + 'a
{
264 (1..self.local_decls
.len()).filter_map(move |index
| {
265 let local
= Local
::new(index
);
266 let decl
= &self.local_decls
[local
];
267 if (decl
.is_user_variable
.is_some() || index
< self.arg_count
+ 1)
268 && decl
.mutability
== Mutability
::Mut
277 /// Returns an iterator over all function arguments.
279 pub fn args_iter(&self) -> impl Iterator
<Item
= Local
> {
280 let arg_count
= self.arg_count
;
281 (1..arg_count
+ 1).map(Local
::new
)
284 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
285 /// locals that are neither arguments nor the return place).
287 pub fn vars_and_temps_iter(&self) -> impl Iterator
<Item
= Local
> {
288 let arg_count
= self.arg_count
;
289 let local_count
= self.local_decls
.len();
290 (arg_count
+ 1..local_count
).map(Local
::new
)
293 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
294 /// invalidating statement indices in `Location`s.
295 pub fn make_statement_nop(&mut self, location
: Location
) {
296 let block
= &mut self[location
.block
];
297 debug_assert
!(location
.statement_index
< block
.statements
.len());
298 block
.statements
[location
.statement_index
].make_nop()
301 /// Returns the source info associated with `location`.
302 pub fn source_info(&self, location
: Location
) -> &SourceInfo
{
303 let block
= &self[location
.block
];
304 let stmts
= &block
.statements
;
305 let idx
= location
.statement_index
;
306 if idx
< stmts
.len() {
307 &stmts
[idx
].source_info
309 assert
!(idx
== stmts
.len());
310 &block
.terminator().source_info
314 /// Check if `sub` is a sub scope of `sup`
315 pub fn is_sub_scope(&self, mut sub
: SourceScope
, sup
: SourceScope
) -> bool
{
320 match self.source_scopes
[sub
].parent_scope
{
321 None
=> return false,
327 /// Return the return type, it always return first element from `local_decls` array
328 pub fn return_ty(&self) -> Ty
<'tcx
> {
329 self.local_decls
[RETURN_PLACE
].ty
333 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
336 /// Unsafe because of a PushUnsafeBlock
338 /// Unsafe because of an unsafe fn
340 /// Unsafe because of an `unsafe` block
341 ExplicitUnsafe(ast
::NodeId
),
344 impl_stable_hash_for
!(struct Mir
<'tcx
> {
347 source_scope_local_data
,
360 impl<'tcx
> Index
<BasicBlock
> for Mir
<'tcx
> {
361 type Output
= BasicBlockData
<'tcx
>;
364 fn index(&self, index
: BasicBlock
) -> &BasicBlockData
<'tcx
> {
365 &self.basic_blocks()[index
]
369 impl<'tcx
> IndexMut
<BasicBlock
> for Mir
<'tcx
> {
371 fn index_mut(&mut self, index
: BasicBlock
) -> &mut BasicBlockData
<'tcx
> {
372 &mut self.basic_blocks_mut()[index
]
376 #[derive(Copy, Clone, Debug)]
377 pub enum ClearCrossCrate
<T
> {
382 impl<T
> ClearCrossCrate
<T
> {
383 pub fn assert_crate_local(self) -> T
{
385 ClearCrossCrate
::Clear
=> bug
!("unwrapping cross-crate data"),
386 ClearCrossCrate
::Set(v
) => v
,
391 impl<T
: serialize
::Encodable
> serialize
::UseSpecializedEncodable
for ClearCrossCrate
<T
> {}
392 impl<T
: serialize
::Decodable
> serialize
::UseSpecializedDecodable
for ClearCrossCrate
<T
> {}
394 /// Grouped information about the source code origin of a MIR entity.
395 /// Intended to be inspected by diagnostics and debuginfo.
396 /// Most passes can work with it as a whole, within a single function.
397 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
398 pub struct SourceInfo
{
399 /// Source span for the AST pertaining to this MIR entity.
402 /// The source scope, keeping track of which bindings can be
403 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
404 pub scope
: SourceScope
,
407 ///////////////////////////////////////////////////////////////////////////
408 // Mutability and borrow kinds
410 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
411 pub enum Mutability
{
416 impl From
<Mutability
> for hir
::Mutability
{
417 fn from(m
: Mutability
) -> Self {
419 Mutability
::Mut
=> hir
::MutMutable
,
420 Mutability
::Not
=> hir
::MutImmutable
,
425 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
426 pub enum BorrowKind
{
427 /// Data must be immutable and is aliasable.
430 /// Data must be immutable but not aliasable. This kind of borrow
431 /// cannot currently be expressed by the user and is used only in
432 /// implicit closure bindings. It is needed when you the closure
433 /// is borrowing or mutating a mutable referent, e.g.:
435 /// let x: &mut isize = ...;
436 /// let y = || *x += 5;
438 /// If we were to try to translate this closure into a more explicit
439 /// form, we'd encounter an error with the code as written:
441 /// struct Env { x: & &mut isize }
442 /// let x: &mut isize = ...;
443 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
444 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
446 /// This is then illegal because you cannot mutate a `&mut` found
447 /// in an aliasable location. To solve, you'd have to translate with
448 /// an `&mut` borrow:
450 /// struct Env { x: & &mut isize }
451 /// let x: &mut isize = ...;
452 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
453 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
455 /// Now the assignment to `**env.x` is legal, but creating a
456 /// mutable pointer to `x` is not because `x` is not mutable. We
457 /// could fix this by declaring `x` as `let mut x`. This is ok in
458 /// user code, if awkward, but extra weird for closures, since the
459 /// borrow is hidden.
461 /// So we introduce a "unique imm" borrow -- the referent is
462 /// immutable, but not aliasable. This solves the problem. For
463 /// simplicity, we don't give users the way to express this
464 /// borrow, it's just used when translating closures.
467 /// Data is mutable and not aliasable.
469 /// True if this borrow arose from method-call auto-ref
470 /// (i.e. `adjustment::Adjust::Borrow`)
471 allow_two_phase_borrow
: bool
,
476 pub fn allows_two_phase_borrow(&self) -> bool
{
478 BorrowKind
::Shared
| BorrowKind
::Unique
=> false,
480 allow_two_phase_borrow
,
481 } => allow_two_phase_borrow
,
486 ///////////////////////////////////////////////////////////////////////////
487 // Variables and temps
491 DEBUG_FORMAT
= "_{}",
492 const RETURN_PLACE
= 0,
495 /// Classifies locals into categories. See `Mir::local_kind`.
496 #[derive(PartialEq, Eq, Debug)]
498 /// User-declared variable binding
500 /// Compiler-introduced temporary
502 /// Function argument
504 /// Location of function's return value
508 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
509 pub struct VarBindingForm
<'tcx
> {
510 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
511 pub binding_mode
: ty
::BindingMode
,
512 /// If an explicit type was provided for this variable binding,
513 /// this holds the source Span of that type.
515 /// NOTE: If you want to change this to a `HirId`, be wary that
516 /// doing so breaks incremental compilation (as of this writing),
517 /// while a `Span` does not cause our tests to fail.
518 pub opt_ty_info
: Option
<Span
>,
519 /// Place of the RHS of the =, or the subject of the `match` where this
520 /// variable is initialized. None in the case of `let PATTERN;`.
521 /// Some((None, ..)) in the case of and `let [mut] x = ...` because
522 /// (a) the right-hand side isn't evaluated as a place expression.
523 /// (b) it gives a way to separate this case from the remaining cases
525 pub opt_match_place
: Option
<(Option
<Place
<'tcx
>>, Span
)>,
528 #[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
529 pub enum BindingForm
<'tcx
> {
530 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
531 Var(VarBindingForm
<'tcx
>),
532 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
534 /// Reference used in a guard expression to ensure immutability.
538 CloneTypeFoldableAndLiftImpls
! { BindingForm<'tcx>, }
540 impl_stable_hash_for
!(struct self::VarBindingForm
<'tcx
> {
546 mod binding_form_impl
{
547 use rustc_data_structures
::stable_hasher
::{HashStable, StableHasher, StableHasherResult}
;
548 use ich
::StableHashingContext
;
550 impl<'a
, 'tcx
> HashStable
<StableHashingContext
<'a
>> for super::BindingForm
<'tcx
> {
551 fn hash_stable
<W
: StableHasherResult
>(&self,
552 hcx
: &mut StableHashingContext
<'a
>,
553 hasher
: &mut StableHasher
<W
>) {
554 use super::BindingForm
::*;
555 ::std
::mem
::discriminant(self).hash_stable(hcx
, hasher
);
558 Var(binding
) => binding
.hash_stable(hcx
, hasher
),
568 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
569 /// argument, or the return place.
570 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
571 pub struct LocalDecl
<'tcx
> {
572 /// `let mut x` vs `let x`.
574 /// Temporaries and the return place are always mutable.
575 pub mutability
: Mutability
,
577 /// Some(binding_mode) if this corresponds to a user-declared local variable.
579 /// This is solely used for local diagnostics when generating
580 /// warnings/errors when compiling the current crate, and
581 /// therefore it need not be visible across crates. pnkfelix
582 /// currently hypothesized we *need* to wrap this in a
583 /// `ClearCrossCrate` as long as it carries as `HirId`.
584 pub is_user_variable
: Option
<ClearCrossCrate
<BindingForm
<'tcx
>>>,
586 /// True if this is an internal local
588 /// These locals are not based on types in the source code and are only used
589 /// for a few desugarings at the moment.
591 /// The generator transformation will sanity check the locals which are live
592 /// across a suspension point against the type components of the generator
593 /// which type checking knows are live across a suspension point. We need to
594 /// flag drop flags to avoid triggering this check as they are introduced
597 /// Unsafety checking will also ignore dereferences of these locals,
598 /// so they can be used for raw pointers only used in a desugaring.
600 /// This should be sound because the drop flags are fully algebraic, and
601 /// therefore don't affect the OIBIT or outlives properties of the
605 /// Type of this local.
608 /// Name of the local, used in debuginfo and pretty-printing.
610 /// Note that function arguments can also have this set to `Some(_)`
611 /// to generate better debuginfo.
612 pub name
: Option
<Name
>,
614 /// The *syntactic* (i.e. not visibility) source scope the local is defined
615 /// in. If the local was defined in a let-statement, this
616 /// is *within* the let-statement, rather than outside
619 /// This is needed because the visibility source scope of locals within
620 /// a let-statement is weird.
622 /// The reason is that we want the local to be *within* the let-statement
623 /// for lint purposes, but we want the local to be *after* the let-statement
624 /// for names-in-scope purposes.
626 /// That's it, if we have a let-statement like the one in this
630 /// fn foo(x: &str) {
631 /// #[allow(unused_mut)]
632 /// let mut x: u32 = { // <- one unused mut
633 /// let mut y: u32 = x.parse().unwrap();
640 /// Then, from a lint point of view, the declaration of `x: u32`
641 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
642 /// lint scopes are the same as the AST/HIR nesting.
644 /// However, from a name lookup point of view, the scopes look more like
645 /// as if the let-statements were `match` expressions:
648 /// fn foo(x: &str) {
650 /// match x.parse().unwrap() {
659 /// We care about the name-lookup scopes for debuginfo - if the
660 /// debuginfo instruction pointer is at the call to `x.parse()`, we
661 /// want `x` to refer to `x: &str`, but if it is at the call to
662 /// `drop(x)`, we want it to refer to `x: u32`.
664 /// To allow both uses to work, we need to have more than a single scope
665 /// for a local. We have the `source_info.scope` represent the
666 /// "syntactic" lint scope (with a variable being under its let
667 /// block) while the `visibility_scope` represents the "local variable"
668 /// scope (where the "rest" of a block is under all prior let-statements).
670 /// The end result looks like this:
674 /// │{ argument x: &str }
676 /// │ │{ #[allow(unused_mut] } // this is actually split into 2 scopes
677 /// │ │ // in practice because I'm lazy.
679 /// │ │← x.source_info.scope
680 /// │ │← `x.parse().unwrap()`
682 /// │ │ │← y.source_info.scope
684 /// │ │ │{ let y: u32 }
686 /// │ │ │← y.visibility_scope
689 /// │ │{ let x: u32 }
690 /// │ │← x.visibility_scope
691 /// │ │← `drop(x)` // this accesses `x: u32`
693 pub source_info
: SourceInfo
,
695 /// Source scope within which the local is visible (for debuginfo)
696 /// (see `source_info` for more details).
697 pub visibility_scope
: SourceScope
,
700 impl<'tcx
> LocalDecl
<'tcx
> {
701 /// Returns true only if local is a binding that can itself be
702 /// made mutable via the addition of the `mut` keyword, namely
703 /// something like the occurrences of `x` in:
704 /// - `fn foo(x: Type) { ... }`,
706 /// - or `match ... { C(x) => ... }`
707 pub fn can_be_made_mutable(&self) -> bool
{
708 match self.is_user_variable
{
709 Some(ClearCrossCrate
::Set(BindingForm
::Var(VarBindingForm
{
710 binding_mode
: ty
::BindingMode
::BindByValue(_
),
715 // FIXME: might be able to thread the distinction between
716 // `self`/`mut self`/`&self`/`&mut self` into the
717 // `BindingForm::ImplicitSelf` variant, (and then return
718 // true here for solely the first case).
723 /// Returns true if local is definitely not a `ref ident` or
724 /// `ref mut ident` binding. (Such bindings cannot be made into
725 /// mutable bindings, but the inverse does not necessarily hold).
726 pub fn is_nonref_binding(&self) -> bool
{
727 match self.is_user_variable
{
728 Some(ClearCrossCrate
::Set(BindingForm
::Var(VarBindingForm
{
729 binding_mode
: ty
::BindingMode
::BindByValue(_
),
734 Some(ClearCrossCrate
::Set(BindingForm
::ImplicitSelf
)) => true,
740 /// Create a new `LocalDecl` for a temporary.
742 pub fn new_temp(ty
: Ty
<'tcx
>, span
: Span
) -> Self {
744 mutability
: Mutability
::Mut
,
747 source_info
: SourceInfo
{
749 scope
: OUTERMOST_SOURCE_SCOPE
,
751 visibility_scope
: OUTERMOST_SOURCE_SCOPE
,
753 is_user_variable
: None
,
757 /// Create a new `LocalDecl` for a internal temporary.
759 pub fn new_internal(ty
: Ty
<'tcx
>, span
: Span
) -> Self {
761 mutability
: Mutability
::Mut
,
764 source_info
: SourceInfo
{
766 scope
: OUTERMOST_SOURCE_SCOPE
,
768 visibility_scope
: OUTERMOST_SOURCE_SCOPE
,
770 is_user_variable
: None
,
774 /// Builds a `LocalDecl` for the return place.
776 /// This must be inserted into the `local_decls` list as the first local.
778 pub fn new_return_place(return_ty
: Ty
, span
: Span
) -> LocalDecl
{
780 mutability
: Mutability
::Mut
,
782 source_info
: SourceInfo
{
784 scope
: OUTERMOST_SOURCE_SCOPE
,
786 visibility_scope
: OUTERMOST_SOURCE_SCOPE
,
788 name
: None
, // FIXME maybe we do want some name here?
789 is_user_variable
: None
,
794 /// A closure capture, with its name and mode.
795 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
796 pub struct UpvarDecl
{
797 pub debug_name
: Name
,
799 /// `HirId` of the captured variable
800 pub var_hir_id
: ClearCrossCrate
<HirId
>,
802 /// If true, the capture is behind a reference.
805 pub mutability
: Mutability
,
808 ///////////////////////////////////////////////////////////////////////////
811 newtype_index
!(BasicBlock { DEBUG_FORMAT = "bb{}
" });
814 pub fn start_location(self) -> Location {
822 ///////////////////////////////////////////////////////////////////////////
823 // BasicBlockData and Terminator
825 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
826 pub struct BasicBlockData<'tcx> {
827 /// List of statements in this block.
828 pub statements: Vec<Statement<'tcx>>,
830 /// Terminator for this block.
832 /// NB. This should generally ONLY be `None` during construction.
833 /// Therefore, you should generally access it via the
834 /// `terminator()` or `terminator_mut()` methods. The only
835 /// exception is that certain passes, such as `simplify_cfg`, swap
836 /// out the terminator temporarily with `None` while they continue
837 /// to recurse over the set of basic blocks.
838 pub terminator: Option<Terminator<'tcx>>,
840 /// If true, this block lies on an unwind path. This is used
841 /// during codegen where distinct kinds of basic blocks may be
842 /// generated (particularly for MSVC cleanup). Unwind blocks must
843 /// only branch to other unwind blocks.
844 pub is_cleanup: bool,
847 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
848 pub struct Terminator<'tcx> {
849 pub source_info: SourceInfo,
850 pub kind: TerminatorKind<'tcx>,
853 #[derive(Clone, RustcEncodable, RustcDecodable)]
854 pub enum TerminatorKind<'tcx> {
855 /// block should have one successor in the graph; we jump there
856 Goto { target: BasicBlock },
858 /// operand evaluates to an integer; jump depending on its value
859 /// to one of the targets, and otherwise fallback to `otherwise`
861 /// discriminant value being tested
862 discr: Operand<'tcx>,
864 /// type of value being tested
867 /// Possible values. The locations to branch to in each case
868 /// are found in the corresponding indices from the `targets` vector.
869 values: Cow<'tcx, [u128]>,
871 /// Possible branch sites. The last element of this vector is used
872 /// for the otherwise branch, so targets.len() == values.len() + 1
874 // This invariant is quite non-obvious and also could be improved.
875 // One way to make this invariant is to have something like this instead:
877 // branches: Vec<(ConstInt, BasicBlock)>,
878 // otherwise: Option<BasicBlock> // exhaustive if None
880 // However we’ve decided to keep this as-is until we figure a case
881 // where some other approach seems to be strictly better than other.
882 targets: Vec<BasicBlock>,
885 /// Indicates that the landing pad is finished and unwinding should
886 /// continue. Emitted by build::scope::diverge_cleanup.
889 /// Indicates that the landing pad is finished and that the process
890 /// should abort. Used to prevent unwinding for foreign items.
893 /// Indicates a normal return. The return place should have
894 /// been filled in by now. This should occur at most once.
897 /// Indicates a terminator that can never be reached.
902 location: Place<'tcx>,
904 unwind: Option<BasicBlock>,
907 /// Drop the Place and assign the new value over it. This ensures
908 /// that the assignment to `P` occurs *even if* the destructor for
909 /// place unwinds. Its semantics are best explained by by the
914 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
922 /// Drop(P, goto BB1, unwind BB2)
925 /// // P is now unitialized
929 /// // P is now unitialized -- its dtor panicked
934 location: Place<'tcx>,
935 value: Operand<'tcx>,
937 unwind: Option<BasicBlock>,
940 /// Block ends with a call of a converging function
942 /// The function that’s being called
944 /// Arguments the function is called with.
945 /// These are owned by the callee, which is free to modify them.
946 /// This allows the memory occupied by "by
-value
" arguments to be
947 /// reused across function calls without duplicating the contents.
948 args: Vec<Operand<'tcx>>,
949 /// Destination for the return value. If some, the call is converging.
950 destination: Option<(Place<'tcx>, BasicBlock)>,
951 /// Cleanups to be done if the call unwinds.
952 cleanup: Option<BasicBlock>,
955 /// Jump to the target if the condition has the expected value,
956 /// otherwise panic with a message and a cleanup target.
960 msg: AssertMessage<'tcx>,
962 cleanup: Option<BasicBlock>,
967 /// The value to return
968 value: Operand<'tcx>,
969 /// Where to resume to
971 /// Cleanup to be done if the generator is dropped at this suspend point
972 drop: Option<BasicBlock>,
975 /// Indicates the end of the dropping of a generator
978 /// A block where control flow only ever takes one real path, but borrowck
979 /// needs to be more conservative.
981 /// The target normal control flow will take
982 real_target: BasicBlock,
983 /// The list of blocks control flow could conceptually take, but won't
985 imaginary_targets: Vec<BasicBlock>,
987 /// A terminator for blocks that only take one path in reality, but where we
988 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
989 /// This can arise in infinite loops with no function calls for example.
991 /// The target normal control flow will take
992 real_target: BasicBlock,
993 /// The imaginary cleanup block link. This particular path will never be taken
994 /// in practice, but in order to avoid fragility we want to always
995 /// consider it in borrowck. We don't want to accept programs which
996 /// pass borrowck only when panic=abort or some assertions are disabled
997 /// due to release vs. debug mode builds. This needs to be an Option because
998 /// of the remove_noop_landing_pads and no_landing_pads passes
999 unwind: Option<BasicBlock>,
1003 pub type Successors<'a> =
1004 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
1005 pub type SuccessorsMut<'a> =
1006 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
1008 impl<'tcx> Terminator<'tcx> {
1009 pub fn successors(&self) -> Successors {
1010 self.kind.successors()
1013 pub fn successors_mut(&mut self) -> SuccessorsMut {
1014 self.kind.successors_mut()
1017 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1021 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1022 self.kind.unwind_mut()
1026 impl<'tcx> TerminatorKind<'tcx> {
1027 pub fn if_<'a, 'gcx>(
1028 tcx: TyCtxt<'a, 'gcx, 'tcx>,
1029 cond: Operand<'tcx>,
1032 ) -> TerminatorKind<'tcx> {
1033 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
1034 TerminatorKind::SwitchInt {
1036 switch_ty: tcx.types.bool,
1037 values: From::from(BOOL_SWITCH_FALSE),
1038 targets: vec![f, t],
1042 pub fn successors(&self) -> Successors {
1043 use self::TerminatorKind::*;
1054 } => None.into_iter().chain(&[]),
1055 Goto { target: ref t }
1058 cleanup: Some(ref t),
1062 destination: Some((_, ref t)),
1089 } => Some(t).into_iter().chain(&[]),
1091 destination: Some((_, ref t)),
1092 cleanup: Some(ref u),
1102 unwind: Some(ref u),
1107 unwind: Some(ref u),
1112 cleanup: Some(ref u),
1117 unwind: Some(ref u),
1118 } => Some(t).into_iter().chain(slice::from_ref(u)),
1119 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1122 ref imaginary_targets,
1123 } => Some(real_target).into_iter().chain(&imaginary_targets[..]),
1127 pub fn successors_mut(&mut self) -> SuccessorsMut {
1128 use self::TerminatorKind::*;
1139 } => None.into_iter().chain(&mut []),
1140 Goto { target: ref mut t }
1143 cleanup: Some(ref mut t),
1147 destination: Some((_, ref mut t)),
1172 real_target: ref mut t,
1174 } => Some(t).into_iter().chain(&mut []),
1176 destination: Some((_, ref mut t)),
1177 cleanup: Some(ref mut u),
1182 drop: Some(ref mut u),
1187 unwind: Some(ref mut u),
1192 unwind: Some(ref mut u),
1197 cleanup: Some(ref mut u),
1201 real_target: ref mut t,
1202 unwind: Some(ref mut u),
1203 } => Some(t).into_iter().chain(slice::from_mut(u)),
1206 } => None.into_iter().chain(&mut targets[..]),
1208 ref mut real_target,
1209 ref mut imaginary_targets,
1210 } => Some(real_target)
1212 .chain(&mut imaginary_targets[..]),
1216 pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
1218 TerminatorKind::Goto { .. }
1219 | TerminatorKind::Resume
1220 | TerminatorKind::Abort
1221 | TerminatorKind::Return
1222 | TerminatorKind::Unreachable
1223 | TerminatorKind::GeneratorDrop
1224 | TerminatorKind::Yield { .. }
1225 | TerminatorKind::SwitchInt { .. }
1226 | TerminatorKind::FalseEdges { .. } => None,
1227 TerminatorKind::Call {
1228 cleanup: ref unwind,
1231 | TerminatorKind::Assert {
1232 cleanup: ref unwind,
1235 | TerminatorKind::DropAndReplace { ref unwind, .. }
1236 | TerminatorKind::Drop { ref unwind, .. }
1237 | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind),
1241 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1243 TerminatorKind::Goto { .. }
1244 | TerminatorKind::Resume
1245 | TerminatorKind::Abort
1246 | TerminatorKind::Return
1247 | TerminatorKind::Unreachable
1248 | TerminatorKind::GeneratorDrop
1249 | TerminatorKind::Yield { .. }
1250 | TerminatorKind::SwitchInt { .. }
1251 | TerminatorKind::FalseEdges { .. } => None,
1252 TerminatorKind::Call {
1253 cleanup: ref mut unwind,
1256 | TerminatorKind::Assert {
1257 cleanup: ref mut unwind,
1260 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1261 | TerminatorKind::Drop { ref mut unwind, .. }
1262 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1267 impl<'tcx> BasicBlockData<'tcx> {
1268 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1276 /// Accessor for terminator.
1278 /// Terminator may not be None after construction of the basic block is complete. This accessor
1279 /// provides a convenience way to reach the terminator.
1280 pub fn terminator(&self) -> &Terminator<'tcx> {
1281 self.terminator.as_ref().expect("invalid terminator state
")
1284 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1285 self.terminator.as_mut().expect("invalid terminator state
")
1288 pub fn retain_statements<F>(&mut self, mut f: F)
1290 F: FnMut(&mut Statement) -> bool,
1292 for s in &mut self.statements {
1299 pub fn expand_statements<F, I>(&mut self, mut f: F)
1301 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1302 I: iter::TrustedLen<Item = Statement<'tcx>>,
1304 // Gather all the iterators we'll need to splice in, and their positions.
1305 let mut splices: Vec<(usize, I)> = vec![];
1306 let mut extra_stmts = 0;
1307 for (i, s) in self.statements.iter_mut().enumerate() {
1308 if let Some(mut new_stmts) = f(s) {
1309 if let Some(first) = new_stmts.next() {
1310 // We can already store the first new statement.
1313 // Save the other statements for optimized splicing.
1314 let remaining = new_stmts.size_hint().0;
1316 splices.push((i + 1 + extra_stmts, new_stmts));
1317 extra_stmts += remaining;
1325 // Splice in the new statements, from the end of the block.
1326 // FIXME(eddyb) This could be more efficient with a "gap buffer
"
1327 // where a range of elements ("gap
") is left uninitialized, with
1328 // splicing adding new elements to the end of that gap and moving
1329 // existing elements from before the gap to the end of the gap.
1330 // For now, this is safe code, emulating a gap but initializing it.
1331 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1332 self.statements.resize(
1335 source_info: SourceInfo {
1337 scope: OUTERMOST_SOURCE_SCOPE,
1339 kind: StatementKind::Nop,
1342 for (splice_start, new_stmts) in splices.into_iter().rev() {
1343 let splice_end = splice_start + new_stmts.size_hint().0;
1344 while gap.end > splice_end {
1347 self.statements.swap(gap.start, gap.end);
1349 self.statements.splice(splice_start..splice_end, new_stmts);
1350 gap.end = splice_start;
1354 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1355 if index < self.statements.len() {
1356 &self.statements[index]
1363 impl<'tcx> Debug for TerminatorKind<'tcx> {
1364 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1365 self.fmt_head(fmt)?;
1366 let successor_count = self.successors().count();
1367 let labels = self.fmt_successor_labels();
1368 assert_eq!(successor_count, labels.len());
1370 match successor_count {
1373 1 => write!(fmt, " -> {:?}
", self.successors().nth(0).unwrap()),
1376 write!(fmt, " -> [")?;
1377 for (i, target) in self.successors().enumerate() {
1381 write!(fmt, "{}
: {:?}
", labels[i], target)?;
1389 impl<'tcx> TerminatorKind<'tcx> {
1390 /// Write the "head
" part of the terminator; that is, its name and the data it uses to pick the
1391 /// successor basic block, if any. The only information not included is the list of possible
1392 /// successors, which may be rendered differently between the text and the graphviz format.
1393 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1394 use self::TerminatorKind::*;
1396 Goto { .. } => write!(fmt, "goto
"),
1398 discr: ref place, ..
1399 } => write!(fmt, "switchInt({:?}
)", place),
1400 Return => write!(fmt, "return"),
1401 GeneratorDrop => write!(fmt, "generator_drop
"),
1402 Resume => write!(fmt, "resume
"),
1403 Abort => write!(fmt, "abort
"),
1404 Yield { ref value, .. } => write!(fmt, "_1
= suspend({:?}
)", value),
1405 Unreachable => write!(fmt, "unreachable
"),
1406 Drop { ref location, .. } => write!(fmt, "drop({:?}
)", location),
1411 } => write!(fmt, "replace({:?}
<- {:?}
)", location, value),
1418 if let Some((ref destination, _)) = *destination {
1419 write!(fmt, "{:?}
= ", destination)?;
1421 write!(fmt, "{:?}
(", func)?;
1422 for (index, arg) in args.iter().enumerate() {
1426 write!(fmt, "{:?}
", arg)?;
1436 write!(fmt, "assert(")?;
1440 write!(fmt, "{:?}
, \"{:?}
\")", cond, msg)
1442 FalseEdges { .. } => write!(fmt, "falseEdges
"),
1443 FalseUnwind { .. } => write!(fmt, "falseUnwind
"),
1447 /// Return the list of labels for the edges to the successor basic blocks.
1448 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1449 use self::TerminatorKind::*;
1451 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1452 Goto { .. } => vec!["".into()],
1458 let size = ty::tls::with(|tcx| {
1459 let param_env = ty::ParamEnv::empty();
1460 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1461 tcx.layout_of(param_env.and(switch_ty)).unwrap().size
1466 let mut s = String::new();
1468 Value::Scalar(Scalar::Bits {
1470 defined: size.bits() as u8,
1477 .chain(iter::once(String::from("otherwise
").into()))
1481 destination: Some(_),
1484 } => vec!["return".into_cow(), "unwind
".into_cow()],
1486 destination: Some(_),
1489 } => vec!["return".into_cow()],
1494 } => vec!["unwind
".into_cow()],
1500 Yield { drop: Some(_), .. } => vec!["resume
".into_cow(), "drop
".into_cow()],
1501 Yield { drop: None, .. } => vec!["resume
".into_cow()],
1502 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1503 vec!["return".into_cow()]
1510 } => vec!["return".into_cow(), "unwind
".into_cow()],
1511 Assert { cleanup: None, .. } => vec!["".into()],
1512 Assert { .. } => vec!["success
".into_cow(), "unwind
".into_cow()],
1514 ref imaginary_targets,
1517 let mut l = vec!["real
".into()];
1518 l.resize(imaginary_targets.len() + 1, "imaginary
".into());
1523 } => vec!["real
".into(), "cleanup
".into()],
1524 FalseUnwind { unwind: None, .. } => vec!["real
".into()],
1529 ///////////////////////////////////////////////////////////////////////////
1532 #[derive(Clone, RustcEncodable, RustcDecodable)]
1533 pub struct Statement<'tcx> {
1534 pub source_info: SourceInfo,
1535 pub kind: StatementKind<'tcx>,
1538 impl<'tcx> Statement<'tcx> {
1539 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1540 /// invalidating statement indices in `Location`s.
1541 pub fn make_nop(&mut self) {
1542 self.kind = StatementKind::Nop
1545 /// Changes a statement to a nop and returns the original statement.
1546 pub fn replace_nop(&mut self) -> Self {
1548 source_info: self.source_info,
1549 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1554 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1555 pub enum StatementKind<'tcx> {
1556 /// Write the RHS Rvalue to the LHS Place.
1557 Assign(Place<'tcx>, Rvalue<'tcx>),
1559 /// This represents all the reading that a pattern match may do
1560 /// (e.g. inspecting constants and discriminant values).
1561 ReadForMatch(Place<'tcx>),
1563 /// Write the discriminant for a variant to the enum Place.
1566 variant_index: usize,
1569 /// Start a live range for the storage of the local.
1572 /// End the current live range for the storage of the local.
1575 /// Execute a piece of inline Assembly.
1577 asm: Box<InlineAsm>,
1578 outputs: Vec<Place<'tcx>>,
1579 inputs: Vec<Operand<'tcx>>,
1582 /// Assert the given places to be valid inhabitants of their type. These statements are
1583 /// currently only interpreted by miri and only generated when "-Z mir
-emit
-validate
" is passed.
1584 /// See <https://internals.rust-lang.org/t/types-as-contracts/5562/73> for more details.
1585 Validate(ValidationOp, Vec<ValidationOperand<'tcx, Place<'tcx>>>),
1587 /// Mark one terminating point of a region scope (i.e. static region).
1588 /// (The starting point(s) arise implicitly from borrows.)
1589 EndRegion(region::Scope),
1591 /// Encodes a user's type assertion. These need to be preserved intact so that NLL can respect
1592 /// them. For example:
1594 /// let (a, b): (T, U) = y;
1596 /// Here we would insert a `UserAssertTy<(T, U)>(y)` instruction to check that the type of `y`
1597 /// is the right thing.
1599 /// `CanonicalTy` is used to capture "inference variables
" from the user's types. For example:
1601 /// let x: Vec<_> = ...;
1602 /// let y: &u32 = ...;
1604 /// would result in `Vec<?0>` and `&'?0 u32` respectively (where `?0` is a canonicalized
1606 UserAssertTy(CanonicalTy<'tcx>, Local),
1608 /// No-op. Useful for deleting instructions without affecting statement indices.
1612 /// The `ValidationOp` describes what happens with each of the operands of a
1613 /// `Validate` statement.
1614 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, PartialEq, Eq)]
1615 pub enum ValidationOp {
1616 /// Recursively traverse the place following the type and validate that all type
1617 /// invariants are maintained. Furthermore, acquire exclusive/read-only access to the
1618 /// memory reachable from the place.
1620 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1623 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1624 /// access *until* the given region ends. Then, access will be recovered.
1625 Suspend(region::Scope),
1628 impl Debug for ValidationOp {
1629 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1630 use self::ValidationOp::*;
1632 Acquire => write!(fmt, "Acquire
"),
1633 Release => write!(fmt, "Release
"),
1634 // (reuse lifetime rendering policy from ppaux.)
1635 Suspend(ref ce) => write!(fmt, "Suspend({}
)", ty::ReScope(*ce)),
1640 // This is generic so that it can be reused by miri
1641 #[derive(Clone, Hash, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1642 pub struct ValidationOperand<'tcx, T> {
1645 pub re: Option<region::Scope>,
1646 pub mutbl: hir::Mutability,
1649 impl<'tcx, T: Debug> Debug for ValidationOperand<'tcx, T> {
1650 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1651 write!(fmt, "{:?}
: {:?}
", self.place, self.ty)?;
1652 if let Some(ce) = self.re {
1653 // (reuse lifetime rendering policy from ppaux.)
1654 write!(fmt, "/{}
", ty::ReScope(ce))?;
1656 if let hir::MutImmutable = self.mutbl {
1657 write!(fmt, " (imm
)")?;
1663 impl<'tcx> Debug for Statement<'tcx> {
1664 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1665 use self::StatementKind::*;
1667 Assign(ref place, ref rv) => write!(fmt, "{:?}
= {:?}
", place, rv),
1668 ReadForMatch(ref place) => write!(fmt, "ReadForMatch({:?}
)", place),
1669 // (reuse lifetime rendering policy from ppaux.)
1670 EndRegion(ref ce) => write!(fmt, "EndRegion({}
)", ty::ReScope(*ce)),
1671 Validate(ref op, ref places) => write!(fmt, "Validate({:?}
, {:?}
)", op, places),
1672 StorageLive(ref place) => write!(fmt, "StorageLive({:?}
)", place),
1673 StorageDead(ref place) => write!(fmt, "StorageDead({:?}
)", place),
1677 } => write!(fmt, "discriminant({:?}
) = {:?}
", place, variant_index),
1682 } => write!(fmt, "asm
!({:?}
: {:?}
: {:?}
)", asm, outputs, inputs),
1683 UserAssertTy(ref c_ty, ref local) => {
1684 write!(fmt, "UserAssertTy({:?}
, {:?}
)", c_ty, local)
1686 Nop => write!(fmt, "nop
"),
1691 ///////////////////////////////////////////////////////////////////////////
1694 /// A path to a value; something that can be evaluated without
1695 /// changing or disturbing program state.
1696 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1697 pub enum Place<'tcx> {
1701 /// static or static mut variable
1702 Static(Box<Static<'tcx>>),
1704 /// Constant code promoted to an injected static
1705 Promoted(Box<(Promoted, Ty<'tcx>)>),
1707 /// projection out of a place (access a field, deref a pointer, etc)
1708 Projection(Box<PlaceProjection<'tcx>>),
1711 /// The def-id of a static, along with its normalized type (which is
1712 /// stored to avoid requiring normalization when reading MIR).
1713 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1714 pub struct Static<'tcx> {
1719 impl_stable_hash_for!(struct Static<'tcx> {
1724 /// The `Projection` data structure defines things of the form `B.x`
1725 /// or `*B` or `B[index]`. Note that it is parameterized because it is
1726 /// shared between `Constant` and `Place`. See the aliases
1727 /// `PlaceProjection` etc below.
1728 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1729 pub struct Projection<'tcx, B, V, T> {
1731 pub elem: ProjectionElem<'tcx, V, T>,
1734 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1735 pub enum ProjectionElem<'tcx, V, T> {
1740 /// These indices are generated by slice patterns. Easiest to explain
1744 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1745 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1746 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1747 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1750 /// index or -index (in Python terms), depending on from_end
1752 /// thing being indexed must be at least this long
1754 /// counting backwards from end?
1758 /// These indices are generated by slice patterns.
1760 /// slice[from:-to] in Python terms.
1766 /// "Downcast
" to a variant of an ADT. Currently, we only introduce
1767 /// this for ADTs with more than one variant. It may be better to
1768 /// just introduce it always, or always for enums.
1769 Downcast(&'tcx AdtDef, usize),
1772 /// Alias for projections as they appear in places, where the base is a place
1773 /// and the index is a local.
1774 pub type PlaceProjection<'tcx> = Projection<'tcx, Place<'tcx>, Local, Ty<'tcx>>;
1776 /// Alias for projections as they appear in places, where the base is a place
1777 /// and the index is a local.
1778 pub type PlaceElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
1780 newtype_index!(Field { DEBUG_FORMAT = "field[{}]" });
1782 impl<'tcx
> Place
<'tcx
> {
1783 pub fn field(self, f
: Field
, ty
: Ty
<'tcx
>) -> Place
<'tcx
> {
1784 self.elem(ProjectionElem
::Field(f
, ty
))
1787 pub fn deref(self) -> Place
<'tcx
> {
1788 self.elem(ProjectionElem
::Deref
)
1791 pub fn downcast(self, adt_def
: &'tcx AdtDef
, variant_index
: usize) -> Place
<'tcx
> {
1792 self.elem(ProjectionElem
::Downcast(adt_def
, variant_index
))
1795 pub fn index(self, index
: Local
) -> Place
<'tcx
> {
1796 self.elem(ProjectionElem
::Index(index
))
1799 pub fn elem(self, elem
: PlaceElem
<'tcx
>) -> Place
<'tcx
> {
1800 Place
::Projection(Box
::new(PlaceProjection { base: self, elem }
))
1804 impl<'tcx
> Debug
for Place
<'tcx
> {
1805 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1809 Local(id
) => write
!(fmt
, "{:?}", id
),
1810 Static(box self::Static { def_id, ty }
) => write
!(
1813 ty
::tls
::with(|tcx
| tcx
.item_path_str(def_id
)),
1816 Promoted(ref promoted
) => write
!(fmt
, "({:?}: {:?})", promoted
.0, promoted
.1),
1817 Projection(ref data
) => match data
.elem
{
1818 ProjectionElem
::Downcast(ref adt_def
, index
) => {
1819 write
!(fmt
, "({:?} as {})", data
.base
, adt_def
.variants
[index
].name
)
1821 ProjectionElem
::Deref
=> write
!(fmt
, "(*{:?})", data
.base
),
1822 ProjectionElem
::Field(field
, ty
) => {
1823 write
!(fmt
, "({:?}.{:?}: {:?})", data
.base
, field
.index(), ty
)
1825 ProjectionElem
::Index(ref index
) => write
!(fmt
, "{:?}[{:?}]", data
.base
, index
),
1826 ProjectionElem
::ConstantIndex
{
1830 } => write
!(fmt
, "{:?}[{:?} of {:?}]", data
.base
, offset
, min_length
),
1831 ProjectionElem
::ConstantIndex
{
1835 } => write
!(fmt
, "{:?}[-{:?} of {:?}]", data
.base
, offset
, min_length
),
1836 ProjectionElem
::Subslice { from, to }
if to
== 0 => {
1837 write
!(fmt
, "{:?}[{:?}:]", data
.base
, from
)
1839 ProjectionElem
::Subslice { from, to }
if from
== 0 => {
1840 write
!(fmt
, "{:?}[:-{:?}]", data
.base
, to
)
1842 ProjectionElem
::Subslice { from, to }
=> {
1843 write
!(fmt
, "{:?}[{:?}:-{:?}]", data
.base
, from
, to
)
1850 ///////////////////////////////////////////////////////////////////////////
1853 newtype_index
!(SourceScope
1855 DEBUG_FORMAT
= "scope[{}]",
1856 const OUTERMOST_SOURCE_SCOPE
= 0,
1859 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1860 pub struct SourceScopeData
{
1862 pub parent_scope
: Option
<SourceScope
>,
1865 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1866 pub struct SourceScopeLocalData
{
1867 /// A NodeId with lint levels equivalent to this scope's lint levels.
1868 pub lint_root
: ast
::NodeId
,
1869 /// The unsafe block that contains this node.
1873 ///////////////////////////////////////////////////////////////////////////
1876 /// These are values that can appear inside an rvalue (or an index
1877 /// place). They are intentionally limited to prevent rvalues from
1878 /// being nested in one another.
1879 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
1880 pub enum Operand
<'tcx
> {
1881 /// Copy: The value must be available for use afterwards.
1883 /// This implies that the type of the place must be `Copy`; this is true
1884 /// by construction during build, but also checked by the MIR type checker.
1886 /// Move: The value (including old borrows of it) will not be used again.
1888 /// Safe for values of all types (modulo future developments towards `?Move`).
1889 /// Correct usage patterns are enforced by the borrow checker for safe code.
1890 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
1892 Constant(Box
<Constant
<'tcx
>>),
1895 impl<'tcx
> Debug
for Operand
<'tcx
> {
1896 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1897 use self::Operand
::*;
1899 Constant(ref a
) => write
!(fmt
, "{:?}", a
),
1900 Copy(ref place
) => write
!(fmt
, "{:?}", place
),
1901 Move(ref place
) => write
!(fmt
, "move {:?}", place
),
1906 impl<'tcx
> Operand
<'tcx
> {
1907 pub fn function_handle
<'a
>(
1908 tcx
: TyCtxt
<'a
, 'tcx
, 'tcx
>,
1910 substs
: &'tcx Substs
<'tcx
>,
1913 let ty
= tcx
.type_of(def_id
).subst(tcx
, substs
);
1914 Operand
::Constant(box Constant
{
1917 literal
: ty
::Const
::zero_sized(tcx
, ty
),
1921 pub fn to_copy(&self) -> Self {
1923 Operand
::Copy(_
) | Operand
::Constant(_
) => self.clone(),
1924 Operand
::Move(ref place
) => Operand
::Copy(place
.clone()),
1929 ///////////////////////////////////////////////////////////////////////////
1932 #[derive(Clone, RustcEncodable, RustcDecodable)]
1933 pub enum Rvalue
<'tcx
> {
1934 /// x (either a move or copy, depending on type of x)
1938 Repeat(Operand
<'tcx
>, u64),
1941 Ref(Region
<'tcx
>, BorrowKind
, Place
<'tcx
>),
1943 /// length of a [X] or [X;n] value
1946 Cast(CastKind
, Operand
<'tcx
>, Ty
<'tcx
>),
1948 BinaryOp(BinOp
, Operand
<'tcx
>, Operand
<'tcx
>),
1949 CheckedBinaryOp(BinOp
, Operand
<'tcx
>, Operand
<'tcx
>),
1951 NullaryOp(NullOp
, Ty
<'tcx
>),
1952 UnaryOp(UnOp
, Operand
<'tcx
>),
1954 /// Read the discriminant of an ADT.
1956 /// Undefined (i.e. no effort is made to make it defined, but there’s no reason why it cannot
1957 /// be defined to return, say, a 0) if ADT is not an enum.
1958 Discriminant(Place
<'tcx
>),
1960 /// Create an aggregate value, like a tuple or struct. This is
1961 /// only needed because we want to distinguish `dest = Foo { x:
1962 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
1963 /// that `Foo` has a destructor. These rvalues can be optimized
1964 /// away after type-checking and before lowering.
1965 Aggregate(Box
<AggregateKind
<'tcx
>>, Vec
<Operand
<'tcx
>>),
1968 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1972 /// Convert unique, zero-sized type for a fn to fn()
1975 /// Convert non capturing closure to fn()
1978 /// Convert safe fn() to unsafe fn()
1981 /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
1982 /// codegen must figure out the details once full monomorphization
1983 /// is known. For example, this could be used to cast from a
1984 /// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<Trait>`
1985 /// (presuming `T: Trait`).
1989 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1990 pub enum AggregateKind
<'tcx
> {
1991 /// The type is of the element
1995 /// The second field is the variant index. It's equal to 0 for struct
1996 /// and union expressions. The fourth field is
1997 /// active field number and is present only for union expressions
1998 /// -- e.g. for a union expression `SomeUnion { c: .. }`, the
1999 /// active field index would identity the field `c`
2000 Adt(&'tcx AdtDef
, usize, &'tcx Substs
<'tcx
>, Option
<usize>),
2002 Closure(DefId
, ClosureSubsts
<'tcx
>),
2003 Generator(DefId
, GeneratorSubsts
<'tcx
>, hir
::GeneratorMovability
),
2006 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2008 /// The `+` operator (addition)
2010 /// The `-` operator (subtraction)
2012 /// The `*` operator (multiplication)
2014 /// The `/` operator (division)
2016 /// The `%` operator (modulus)
2018 /// The `^` operator (bitwise xor)
2020 /// The `&` operator (bitwise and)
2022 /// The `|` operator (bitwise or)
2024 /// The `<<` operator (shift left)
2026 /// The `>>` operator (shift right)
2028 /// The `==` operator (equality)
2030 /// The `<` operator (less than)
2032 /// The `<=` operator (less than or equal to)
2034 /// The `!=` operator (not equal to)
2036 /// The `>=` operator (greater than or equal to)
2038 /// The `>` operator (greater than)
2040 /// The `ptr.offset` operator
2045 pub fn is_checkable(self) -> bool
{
2048 Add
| Sub
| Mul
| Shl
| Shr
=> true,
2054 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2056 /// Return the size of a value of that type
2058 /// Create a new uninitialized box for a value of that type
2062 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
2064 /// The `!` operator for logical inversion
2066 /// The `-` operator for negation
2070 impl<'tcx
> Debug
for Rvalue
<'tcx
> {
2071 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
2072 use self::Rvalue
::*;
2075 Use(ref place
) => write
!(fmt
, "{:?}", place
),
2076 Repeat(ref a
, ref b
) => write
!(fmt
, "[{:?}; {:?}]", a
, b
),
2077 Len(ref a
) => write
!(fmt
, "Len({:?})", a
),
2078 Cast(ref kind
, ref place
, ref ty
) => {
2079 write
!(fmt
, "{:?} as {:?} ({:?})", place
, ty
, kind
)
2081 BinaryOp(ref op
, ref a
, ref b
) => write
!(fmt
, "{:?}({:?}, {:?})", op
, a
, b
),
2082 CheckedBinaryOp(ref op
, ref a
, ref b
) => {
2083 write
!(fmt
, "Checked{:?}({:?}, {:?})", op
, a
, b
)
2085 UnaryOp(ref op
, ref a
) => write
!(fmt
, "{:?}({:?})", op
, a
),
2086 Discriminant(ref place
) => write
!(fmt
, "discriminant({:?})", place
),
2087 NullaryOp(ref op
, ref t
) => write
!(fmt
, "{:?}({:?})", op
, t
),
2088 Ref(region
, borrow_kind
, ref place
) => {
2089 let kind_str
= match borrow_kind
{
2090 BorrowKind
::Shared
=> "",
2091 BorrowKind
::Mut { .. }
| BorrowKind
::Unique
=> "mut ",
2094 // When printing regions, add trailing space if necessary.
2095 let region
= if ppaux
::verbose() || ppaux
::identify_regions() {
2096 let mut region
= region
.to_string();
2097 if region
.len() > 0 {
2102 // Do not even print 'static
2105 write
!(fmt
, "&{}{}{:?}", region
, kind_str
, place
)
2108 Aggregate(ref kind
, ref places
) => {
2109 fn fmt_tuple(fmt
: &mut Formatter
, places
: &[Operand
]) -> fmt
::Result
{
2110 let mut tuple_fmt
= fmt
.debug_tuple("");
2111 for place
in places
{
2112 tuple_fmt
.field(place
);
2118 AggregateKind
::Array(_
) => write
!(fmt
, "{:?}", places
),
2120 AggregateKind
::Tuple
=> match places
.len() {
2121 0 => write
!(fmt
, "()"),
2122 1 => write
!(fmt
, "({:?},)", places
[0]),
2123 _
=> fmt_tuple(fmt
, places
),
2126 AggregateKind
::Adt(adt_def
, variant
, substs
, _
) => {
2127 let variant_def
= &adt_def
.variants
[variant
];
2129 ppaux
::parameterized(fmt
, substs
, variant_def
.did
, &[])?
;
2131 match variant_def
.ctor_kind
{
2132 CtorKind
::Const
=> Ok(()),
2133 CtorKind
::Fn
=> fmt_tuple(fmt
, places
),
2134 CtorKind
::Fictive
=> {
2135 let mut struct_fmt
= fmt
.debug_struct("");
2136 for (field
, place
) in variant_def
.fields
.iter().zip(places
) {
2137 struct_fmt
.field(&field
.ident
.as_str(), place
);
2144 AggregateKind
::Closure(def_id
, _
) => ty
::tls
::with(|tcx
| {
2145 if let Some(node_id
) = tcx
.hir
.as_local_node_id(def_id
) {
2146 let name
= if tcx
.sess
.opts
.debugging_opts
.span_free_formats
{
2147 format
!("[closure@{:?}]", node_id
)
2149 format
!("[closure@{:?}]", tcx
.hir
.span(node_id
))
2151 let mut struct_fmt
= fmt
.debug_struct(&name
);
2153 tcx
.with_freevars(node_id
, |freevars
| {
2154 for (freevar
, place
) in freevars
.iter().zip(places
) {
2155 let var_name
= tcx
.hir
.name(freevar
.var_id());
2156 struct_fmt
.field(&var_name
.as_str(), place
);
2162 write
!(fmt
, "[closure]")
2166 AggregateKind
::Generator(def_id
, _
, _
) => ty
::tls
::with(|tcx
| {
2167 if let Some(node_id
) = tcx
.hir
.as_local_node_id(def_id
) {
2168 let name
= format
!("[generator@{:?}]", tcx
.hir
.span(node_id
));
2169 let mut struct_fmt
= fmt
.debug_struct(&name
);
2171 tcx
.with_freevars(node_id
, |freevars
| {
2172 for (freevar
, place
) in freevars
.iter().zip(places
) {
2173 let var_name
= tcx
.hir
.name(freevar
.var_id());
2174 struct_fmt
.field(&var_name
.as_str(), place
);
2176 struct_fmt
.field("$state", &places
[freevars
.len()]);
2177 for i
in (freevars
.len() + 1)..places
.len() {
2179 .field(&format
!("${}", i
- freevars
.len() - 1), &places
[i
]);
2185 write
!(fmt
, "[generator]")
2194 ///////////////////////////////////////////////////////////////////////////
2197 /// Two constants are equal if they are the same constant. Note that
2198 /// this does not necessarily mean that they are "==" in Rust -- in
2199 /// particular one must be wary of `NaN`!
2201 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2202 pub struct Constant
<'tcx
> {
2205 pub literal
: &'tcx ty
::Const
<'tcx
>,
2208 newtype_index
!(Promoted { DEBUG_FORMAT = "promoted[{}
]" });
2210 impl<'tcx> Debug for Constant<'tcx> {
2211 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
2212 write!(fmt, "const ")?;
2213 fmt_const_val(fmt, self.literal)
2217 /// Write a `ConstValue` in a way closer to the original source code than the `Debug` output.
2218 pub fn fmt_const_val<W: Write>(fmt: &mut W, const_val: &ty::Const) -> fmt::Result {
2219 if let Some(value) = const_val.to_byval_value() {
2220 print_miri_value(value, const_val.ty, fmt)
2222 write!(fmt, "{:?}
:{}
", const_val.val, const_val.ty)
2226 pub fn print_miri_value<W: Write>(value: Value, ty: Ty, f: &mut W) -> fmt::Result {
2227 use ty::TypeVariants::*;
2228 match (value, &ty.sty) {
2229 (Value::Scalar(Scalar::Bits { bits: 0, .. }), &TyBool) => write!(f, "false"),
2230 (Value::Scalar(Scalar::Bits { bits: 1, .. }), &TyBool) => write!(f, "true"),
2231 (Value::Scalar(Scalar::Bits { bits, .. }), &TyFloat(ast::FloatTy::F32)) => {
2232 write!(f, "{}
f32", Single::from_bits(bits))
2234 (Value::Scalar(Scalar::Bits { bits, .. }), &TyFloat(ast::FloatTy::F64)) => {
2235 write!(f, "{}
f64", Double::from_bits(bits))
2237 (Value::Scalar(Scalar::Bits { bits, .. }), &TyUint(ui)) => write!(f, "{:?}{}
", bits, ui),
2238 (Value::Scalar(Scalar::Bits { bits, .. }), &TyInt(i)) => {
2239 let bit_width = ty::tls::with(|tcx| {
2240 let ty = tcx.lift_to_global(&ty).unwrap();
2241 tcx.layout_of(ty::ParamEnv::empty().and(ty))
2246 let shift = 128 - bit_width;
2247 write!(f, "{:?}{}
", ((bits as i128) << shift) >> shift, i)
2249 (Value::Scalar(Scalar::Bits { bits, .. }), &TyChar) => {
2250 write!(f, "{:?}
", ::std::char::from_u32(bits as u32).unwrap())
2252 (_, &TyFnDef(did, _)) => write!(f, "{}
", item_path_str(did)),
2254 Value::ScalarPair(Scalar::Ptr(ptr), Scalar::Bits { bits: len, .. }),
2255 &TyRef(_, &ty::TyS { sty: TyStr, .. }, _),
2256 ) => ty::tls::with(|tcx| match tcx.alloc_map.lock().get(ptr.alloc_id) {
2257 Some(interpret::AllocType::Memory(alloc)) => {
2258 assert_eq!(len as usize as u128, len);
2259 let slice = &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
2260 let s = ::std::str::from_utf8(slice).expect("non utf8
str from miri
");
2261 write!(f, "{:?}
", s)
2263 _ => write!(f, "pointer to erroneous constant {:?}
, {:?}
", ptr, len),
2265 _ => write!(f, "{:?}
:{}
", value, ty),
2269 fn item_path_str(def_id: DefId) -> String {
2270 ty::tls::with(|tcx| tcx.item_path_str(def_id))
2273 impl<'tcx> graph::DirectedGraph for Mir<'tcx> {
2274 type Node = BasicBlock;
2277 impl<'tcx> graph::WithNumNodes for Mir<'tcx> {
2278 fn num_nodes(&self) -> usize {
2279 self.basic_blocks.len()
2283 impl<'tcx> graph::WithStartNode for Mir<'tcx> {
2284 fn start_node(&self) -> Self::Node {
2289 impl<'tcx> graph::WithPredecessors for Mir<'tcx> {
2290 fn predecessors<'graph>(
2293 ) -> <Self as GraphPredecessors<'graph>>::Iter {
2294 self.predecessors_for(node).clone().into_iter()
2298 impl<'tcx> graph::WithSuccessors for Mir<'tcx> {
2299 fn successors<'graph>(
2302 ) -> <Self as GraphSuccessors<'graph>>::Iter {
2303 self.basic_blocks[node].terminator().successors().cloned()
2307 impl<'a, 'b> graph::GraphPredecessors<'b> for Mir<'a> {
2308 type Item = BasicBlock;
2309 type Iter = IntoIter<BasicBlock>;
2312 impl<'a, 'b> graph::GraphSuccessors<'b> for Mir<'a> {
2313 type Item = BasicBlock;
2314 type Iter = iter::Cloned<Successors<'b>>;
2317 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
2318 pub struct Location {
2319 /// the location is within this block
2320 pub block: BasicBlock,
2322 /// the location is the start of the statement; or, if `statement_index`
2323 /// == num-statements, then the start of the terminator.
2324 pub statement_index: usize,
2327 impl fmt::Debug for Location {
2328 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2329 write!(fmt, "{:?}
[{}
]", self.block, self.statement_index)
2334 pub const START: Location = Location {
2339 /// Returns the location immediately after this one within the enclosing block.
2341 /// Note that if this location represents a terminator, then the
2342 /// resulting location would be out of bounds and invalid.
2343 pub fn successor_within_block(&self) -> Location {
2346 statement_index: self.statement_index + 1,
2350 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2351 if self.block == other.block {
2352 self.statement_index <= other.statement_index
2354 dominators.is_dominated_by(other.block, self.block)
2359 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2360 pub enum UnsafetyViolationKind {
2362 ExternStatic(ast::NodeId),
2363 BorrowPacked(ast::NodeId),
2366 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2367 pub struct UnsafetyViolation {
2368 pub source_info: SourceInfo,
2369 pub description: InternedString,
2370 pub details: InternedString,
2371 pub kind: UnsafetyViolationKind,
2374 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2375 pub struct UnsafetyCheckResult {
2376 /// Violations that are propagated *upwards* from this function
2377 pub violations: Lrc<[UnsafetyViolation]>,
2378 /// unsafe blocks in this function, along with whether they are used. This is
2379 /// used for the "unused_unsafe
" lint.
2380 pub unsafe_blocks: Lrc<[(ast::NodeId, bool)]>,
2383 /// The layout of generator state
2384 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2385 pub struct GeneratorLayout<'tcx> {
2386 pub fields: Vec<LocalDecl<'tcx>>,
2389 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2390 pub struct BorrowCheckResult<'gcx> {
2391 pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
2392 pub used_mut_upvars: SmallVec<[Field; 8]>,
2395 /// After we borrow check a closure, we are left with various
2396 /// requirements that we have inferred between the free regions that
2397 /// appear in the closure's signature or on its field types. These
2398 /// requirements are then verified and proved by the closure's
2399 /// creating function. This struct encodes those requirements.
2401 /// The requirements are listed as being between various
2402 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2403 /// vids refer to the free regions that appear in the closure (or
2404 /// generator's) type, in order of appearance. (This numbering is
2405 /// actually defined by the `UniversalRegions` struct in the NLL
2406 /// region checker. See for example
2407 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2408 /// regions in the closure's type "as if" they were erased, so their
2409 /// precise identity is not important, only their position.
2411 /// Example: If type check produces a closure with the closure substs:
2414 /// ClosureSubsts = [
2415 /// i8, // the "closure kind
"
2416 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature
"
2417 /// &'a String, // some upvar
2421 /// here, there is one unique free region (`'a`) but it appears
2422 /// twice. We would "renumber
" each occurrence to a unique vid, as follows:
2425 /// ClosureSubsts = [
2426 /// i8, // the "closure kind
"
2427 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature
"
2428 /// &'2 String, // some upvar
2432 /// Now the code might impose a requirement like `'1: '2`. When an
2433 /// instance of the closure is created, the corresponding free regions
2434 /// can be extracted from its type and constrained to have the given
2435 /// outlives relationship.
2437 /// In some cases, we have to record outlives requirements between
2438 /// types and regions as well. In that case, if those types include
2439 /// any regions, those regions are recorded as `ReClosureBound`
2440 /// instances assigned one of these same indices. Those regions will
2441 /// be substituted away by the creator. We use `ReClosureBound` in
2442 /// that case because the regions must be allocated in the global
2443 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
2444 /// internally within the rest of the NLL code).
2445 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2446 pub struct ClosureRegionRequirements<'gcx> {
2447 /// The number of external regions defined on the closure. In our
2448 /// example above, it would be 3 -- one for `'static`, then `'1`
2449 /// and `'2`. This is just used for a sanity check later on, to
2450 /// make sure that the number of regions we see at the callsite
2452 pub num_external_vids: usize,
2454 /// Requirements between the various free regions defined in
2456 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
2459 /// Indicates an outlives constraint between a type or between two
2460 /// free-regions declared on the closure.
2461 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2462 pub struct ClosureOutlivesRequirement<'tcx> {
2463 // This region or type ...
2464 pub subject: ClosureOutlivesSubject<'tcx>,
2466 // .. must outlive this one.
2467 pub outlived_free_region: ty::RegionVid,
2469 // If not, report an error here.
2470 pub blame_span: Span,
2473 /// The subject of a ClosureOutlivesRequirement -- that is, the thing
2474 /// that must outlive some region.
2475 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2476 pub enum ClosureOutlivesSubject<'tcx> {
2477 /// Subject is a type, typically a type parameter, but could also
2478 /// be a projection. Indicates a requirement like `T: 'a` being
2479 /// passed to the caller, where the type here is `T`.
2481 /// The type here is guaranteed not to contain any free regions at
2485 /// Subject is a free region from the closure. Indicates a requirement
2486 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2487 Region(ty::RegionVid),
2491 * TypeFoldable implementations for MIR types
2494 CloneTypeFoldableAndLiftImpls! {
2501 SourceScopeLocalData,
2504 BraceStructTypeFoldableImpl! {
2505 impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
2508 source_scope_local_data,
2522 BraceStructTypeFoldableImpl! {
2523 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
2528 BraceStructTypeFoldableImpl! {
2529 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
2540 BraceStructTypeFoldableImpl! {
2541 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
2548 BraceStructTypeFoldableImpl! {
2549 impl<'tcx> TypeFoldable<'tcx> for ValidationOperand<'tcx, Place<'tcx>> {
2550 place, ty, re, mutbl
2554 BraceStructTypeFoldableImpl! {
2555 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
2560 EnumTypeFoldableImpl! {
2561 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
2562 (StatementKind::Assign)(a, b),
2563 (StatementKind::ReadForMatch)(place),
2564 (StatementKind::SetDiscriminant) { place, variant_index },
2565 (StatementKind::StorageLive)(a),
2566 (StatementKind::StorageDead)(a),
2567 (StatementKind::InlineAsm) { asm, outputs, inputs },
2568 (StatementKind::Validate)(a, b),
2569 (StatementKind::EndRegion)(a),
2570 (StatementKind::UserAssertTy)(a, b),
2571 (StatementKind::Nop),
2575 EnumTypeFoldableImpl! {
2576 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
2577 (ClearCrossCrate::Clear),
2578 (ClearCrossCrate::Set)(a),
2579 } where T: TypeFoldable<'tcx>
2582 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2583 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2584 use mir::TerminatorKind::*;
2586 let kind = match self.kind {
2587 Goto { target } => Goto { target: target },
2594 discr: discr.fold_with(folder),
2595 switch_ty: switch_ty.fold_with(folder),
2596 values: values.clone(),
2597 targets: targets.clone(),
2604 location: location.fold_with(folder),
2613 } => DropAndReplace {
2614 location: location.fold_with(folder),
2615 value: value.fold_with(folder),
2624 value: value.fold_with(folder),
2634 let dest = destination
2636 .map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2639 func: func.fold_with(folder),
2640 args: args.fold_with(folder),
2652 let msg = if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2653 EvalErrorKind::BoundsCheck {
2654 len: len.fold_with(folder),
2655 index: index.fold_with(folder),
2661 cond: cond.fold_with(folder),
2668 GeneratorDrop => GeneratorDrop,
2672 Unreachable => Unreachable,
2675 ref imaginary_targets,
2678 imaginary_targets: imaginary_targets.clone(),
2689 source_info: self.source_info,
2694 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2695 use mir::TerminatorKind::*;
2702 } => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
2703 Drop { ref location, .. } => location.visit_with(visitor),
2708 } => location.visit_with(visitor) || value.visit_with(visitor),
2709 Yield { ref value, .. } => value.visit_with(visitor),
2716 let dest = if let Some((ref loc, _)) = *destination {
2717 loc.visit_with(visitor)
2721 dest || func.visit_with(visitor) || args.visit_with(visitor)
2724 ref cond, ref msg, ..
2726 if cond.visit_with(visitor) {
2727 if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2728 len.visit_with(visitor) || index.visit_with(visitor)
2743 | FalseUnwind { .. } => false,
2748 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2749 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2751 &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
2756 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2757 if let &Place::Projection(ref p) = self {
2758 p.visit_with(visitor)
2765 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
2766 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2769 Use(ref op) => Use(op.fold_with(folder)),
2770 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
2771 Ref(region, bk, ref place) => {
2772 Ref(region.fold_with(folder), bk, place.fold_with(folder))
2774 Len(ref place) => Len(place.fold_with(folder)),
2775 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
2776 BinaryOp(op, ref rhs, ref lhs) => {
2777 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2779 CheckedBinaryOp(op, ref rhs, ref lhs) => {
2780 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2782 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
2783 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
2784 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
2785 Aggregate(ref kind, ref fields) => {
2786 let kind = box match **kind {
2787 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
2788 AggregateKind::Tuple => AggregateKind::Tuple,
2789 AggregateKind::Adt(def, v, substs, n) => {
2790 AggregateKind::Adt(def, v, substs.fold_with(folder), n)
2792 AggregateKind::Closure(id, substs) => {
2793 AggregateKind::Closure(id, substs.fold_with(folder))
2795 AggregateKind::Generator(id, substs, movablity) => {
2796 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
2799 Aggregate(kind, fields.fold_with(folder))
2804 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2807 Use(ref op) => op.visit_with(visitor),
2808 Repeat(ref op, _) => op.visit_with(visitor),
2809 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
2810 Len(ref place) => place.visit_with(visitor),
2811 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
2812 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
2813 rhs.visit_with(visitor) || lhs.visit_with(visitor)
2815 UnaryOp(_, ref val) => val.visit_with(visitor),
2816 Discriminant(ref place) => place.visit_with(visitor),
2817 NullaryOp(_, ty) => ty.visit_with(visitor),
2818 Aggregate(ref kind, ref fields) => {
2820 AggregateKind::Array(ty) => ty.visit_with(visitor),
2821 AggregateKind::Tuple => false,
2822 AggregateKind::Adt(_, _, substs, _) => substs.visit_with(visitor),
2823 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
2824 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
2825 }) || fields.visit_with(visitor)
2831 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
2832 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2834 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
2835 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
2836 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
2840 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2842 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
2843 Operand::Constant(ref c) => c.visit_with(visitor),
2848 impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<'tcx, B, V, T>
2850 B: TypeFoldable<'tcx>,
2851 V: TypeFoldable<'tcx>,
2852 T: TypeFoldable<'tcx>,
2854 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2855 use mir::ProjectionElem::*;
2857 let base = self.base.fold_with(folder);
2858 let elem = match self.elem {
2860 Field(f, ref ty) => Field(f, ty.fold_with(folder)),
2861 Index(ref v) => Index(v.fold_with(folder)),
2862 ref elem => elem.clone(),
2865 Projection { base, elem }
2868 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2869 use mir::ProjectionElem::*;
2871 self.base.visit_with(visitor) || match self.elem {
2872 Field(_, ref ty) => ty.visit_with(visitor),
2873 Index(ref v) => v.visit_with(visitor),
2879 impl<'tcx> TypeFoldable<'tcx> for Field {
2880 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
2883 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
2888 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
2889 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2891 span: self.span.clone(),
2892 ty: self.ty.fold_with(folder),
2893 literal: self.literal.fold_with(folder),
2896 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2897 self.ty.visit_with(visitor) || self.literal.visit_with(visitor)