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.html
15 use graphviz::IntoCow;
16 use hir::def::CtorKind;
17 use hir::def_id::DefId;
18 use hir::{self, 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::control_flow_graph::dominators::{dominators, Dominators};
25 use rustc_data_structures::control_flow_graph::ControlFlowGraph;
26 use rustc_data_structures::control_flow_graph::{GraphPredecessors, GraphSuccessors};
27 use rustc_data_structures::indexed_vec::{Idx, IndexVec};
28 use rustc_data_structures::small_vec::SmallVec;
29 use rustc_data_structures::sync::Lrc;
30 use rustc_data_structures::sync::ReadGuard;
31 use rustc_serialize as serialize;
33 use std::fmt::{self, Debug, Formatter, Write};
34 use std::ops::{Index, IndexMut};
36 use std::vec::IntoIter;
37 use std::{iter, mem, option, u32};
38 use syntax::ast::{self, Name};
39 use syntax::symbol::InternedString;
40 use syntax_pos::{Span, DUMMY_SP};
41 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
42 use ty::subst::{Subst, Substs};
43 use ty::{self, AdtDef, CanonicalTy, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt};
46 pub use mir::interpret::AssertMessage;
56 type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
58 pub trait HasLocalDecls<'tcx> {
59 fn local_decls(&self) -> &LocalDecls<'tcx>;
62 impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
63 fn local_decls(&self) -> &LocalDecls<'tcx> {
68 impl<'tcx> HasLocalDecls<'tcx> for Mir<'tcx> {
69 fn local_decls(&self) -> &LocalDecls<'tcx> {
74 /// Lowered representation of a single function.
75 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
76 pub struct Mir<'tcx> {
77 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
78 /// that indexes into this vector.
79 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
81 /// List of source scopes; these are referenced by statements
82 /// and used for debuginfo. Indexed by a `SourceScope`.
83 pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
85 /// Crate-local information for each source scope, that can't (and
86 /// needn't) be tracked across crates.
87 pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
89 /// Rvalues promoted from this function, such as borrows of constants.
90 /// Each of them is the Mir of a constant with the fn's type parameters
91 /// in scope, but a separate set of locals.
92 pub promoted: IndexVec<Promoted, Mir<'tcx>>,
94 /// Yield type of the function, if it is a generator.
95 pub yield_ty: Option<Ty<'tcx>>,
97 /// Generator drop glue
98 pub generator_drop: Option<Box<Mir<'tcx>>>,
100 /// The layout of a generator. Produced by the state transformation.
101 pub generator_layout: Option<GeneratorLayout<'tcx>>,
103 /// Declarations of locals.
105 /// The first local is the return value pointer, followed by `arg_count`
106 /// locals for the function arguments, followed by any user-declared
107 /// variables and temporaries.
108 pub local_decls: LocalDecls<'tcx>,
110 /// Number of arguments this function takes.
112 /// Starting at local 1, `arg_count` locals will be provided by the caller
113 /// and can be assumed to be initialized.
115 /// If this MIR was built for a constant, this will be 0.
116 pub arg_count: usize,
118 /// Names and capture modes of all the closure upvars, assuming
119 /// the first argument is either the closure or a reference to it.
120 pub upvar_decls: Vec<UpvarDecl>,
122 /// Mark an argument local (which must be a tuple) as getting passed as
123 /// its individual components at the LLVM level.
125 /// This is used for the "rust-call" ABI.
126 pub spread_arg: Option<Local>,
128 /// A span representing this MIR, for error reporting
131 /// A cache for various calculations
135 /// where execution begins
136 pub const START_BLOCK: BasicBlock = BasicBlock(0);
138 impl<'tcx> Mir<'tcx> {
140 basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
141 source_scopes: IndexVec<SourceScope, SourceScopeData>,
142 source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
143 promoted: IndexVec<Promoted, Mir<'tcx>>,
144 yield_ty: Option<Ty<'tcx>>,
145 local_decls: IndexVec<Local, LocalDecl<'tcx>>,
147 upvar_decls: Vec<UpvarDecl>,
150 // We need `arg_count` locals, and one for the return place
152 local_decls.len() >= arg_count + 1,
153 "expected at least {} locals, got {}",
161 source_scope_local_data,
164 generator_drop: None,
165 generator_layout: None,
171 cache: cache::Cache::new(),
176 pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
181 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
182 self.cache.invalidate();
183 &mut self.basic_blocks
187 pub fn basic_blocks_and_local_decls_mut(
190 &mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
191 &mut LocalDecls<'tcx>,
193 self.cache.invalidate();
194 (&mut self.basic_blocks, &mut self.local_decls)
198 pub fn predecessors(&self) -> ReadGuard<IndexVec<BasicBlock, Vec<BasicBlock>>> {
199 self.cache.predecessors(self)
203 pub fn predecessors_for(&self, bb: BasicBlock) -> ReadGuard<Vec<BasicBlock>> {
204 ReadGuard::map(self.predecessors(), |p| &p[bb])
208 pub fn dominators(&self) -> Dominators<BasicBlock> {
213 pub fn local_kind(&self, local: Local) -> LocalKind {
214 let index = local.0 as usize;
217 self.local_decls[local].mutability == Mutability::Mut,
218 "return place should be mutable"
221 LocalKind::ReturnPointer
222 } else if index < self.arg_count + 1 {
224 } else if self.local_decls[local].name.is_some() {
228 self.local_decls[local].mutability == Mutability::Mut,
229 "temp should be mutable"
236 /// Returns an iterator over all temporaries.
238 pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
239 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
240 let local = Local::new(index);
241 if self.local_decls[local].is_user_variable.is_some() {
249 /// Returns an iterator over all user-declared locals.
251 pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
252 (self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
253 let local = Local::new(index);
254 if self.local_decls[local].is_user_variable.is_some() {
262 /// Returns an iterator over all user-declared mutable arguments and locals.
264 pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
265 (1..self.local_decls.len()).filter_map(move |index| {
266 let local = Local::new(index);
267 let decl = &self.local_decls[local];
268 if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
269 && decl.mutability == Mutability::Mut
278 /// Returns an iterator over all function arguments.
280 pub fn args_iter(&self) -> impl Iterator<Item = Local> {
281 let arg_count = self.arg_count;
282 (1..arg_count + 1).map(Local::new)
285 /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
286 /// locals that are neither arguments nor the return place).
288 pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
289 let arg_count = self.arg_count;
290 let local_count = self.local_decls.len();
291 (arg_count + 1..local_count).map(Local::new)
294 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
295 /// invalidating statement indices in `Location`s.
296 pub fn make_statement_nop(&mut self, location: Location) {
297 let block = &mut self[location.block];
298 debug_assert!(location.statement_index < block.statements.len());
299 block.statements[location.statement_index].make_nop()
302 /// Returns the source info associated with `location`.
303 pub fn source_info(&self, location: Location) -> &SourceInfo {
304 let block = &self[location.block];
305 let stmts = &block.statements;
306 let idx = location.statement_index;
307 if idx < stmts.len() {
308 &stmts[idx].source_info
310 assert!(idx == stmts.len());
311 &block.terminator().source_info
315 /// Check if `sub` is a sub scope of `sup`
316 pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
321 match self.source_scopes[sub].parent_scope {
322 None => return false,
328 /// Return the return type, it always return first element from `local_decls` array
329 pub fn return_ty(&self) -> Ty<'tcx> {
330 self.local_decls[RETURN_PLACE].ty
334 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
337 /// Unsafe because of a PushUnsafeBlock
339 /// Unsafe because of an unsafe fn
341 /// Unsafe because of an `unsafe` block
342 ExplicitUnsafe(ast::NodeId),
345 impl_stable_hash_for!(struct Mir<'tcx> {
348 source_scope_local_data,
361 impl<'tcx> Index<BasicBlock> for Mir<'tcx> {
362 type Output = BasicBlockData<'tcx>;
365 fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
366 &self.basic_blocks()[index]
370 impl<'tcx> IndexMut<BasicBlock> for Mir<'tcx> {
372 fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
373 &mut self.basic_blocks_mut()[index]
377 #[derive(Copy, Clone, Debug)]
378 pub enum ClearCrossCrate<T> {
383 impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
384 impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
386 /// Grouped information about the source code origin of a MIR entity.
387 /// Intended to be inspected by diagnostics and debuginfo.
388 /// Most passes can work with it as a whole, within a single function.
389 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash)]
390 pub struct SourceInfo {
391 /// Source span for the AST pertaining to this MIR entity.
394 /// The source scope, keeping track of which bindings can be
395 /// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
396 pub scope: SourceScope,
399 ///////////////////////////////////////////////////////////////////////////
400 // Mutability and borrow kinds
402 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
403 pub enum Mutability {
408 impl From<Mutability> for hir::Mutability {
409 fn from(m: Mutability) -> Self {
411 Mutability::Mut => hir::MutMutable,
412 Mutability::Not => hir::MutImmutable,
417 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
418 pub enum BorrowKind {
419 /// Data must be immutable and is aliasable.
422 /// Data must be immutable but not aliasable. This kind of borrow
423 /// cannot currently be expressed by the user and is used only in
424 /// implicit closure bindings. It is needed when you the closure
425 /// is borrowing or mutating a mutable referent, e.g.:
427 /// let x: &mut isize = ...;
428 /// let y = || *x += 5;
430 /// If we were to try to translate this closure into a more explicit
431 /// form, we'd encounter an error with the code as written:
433 /// struct Env { x: & &mut isize }
434 /// let x: &mut isize = ...;
435 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
436 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
438 /// This is then illegal because you cannot mutate a `&mut` found
439 /// in an aliasable location. To solve, you'd have to translate with
440 /// an `&mut` borrow:
442 /// struct Env { x: & &mut isize }
443 /// let x: &mut isize = ...;
444 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
445 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
447 /// Now the assignment to `**env.x` is legal, but creating a
448 /// mutable pointer to `x` is not because `x` is not mutable. We
449 /// could fix this by declaring `x` as `let mut x`. This is ok in
450 /// user code, if awkward, but extra weird for closures, since the
451 /// borrow is hidden.
453 /// So we introduce a "unique imm" borrow -- the referent is
454 /// immutable, but not aliasable. This solves the problem. For
455 /// simplicity, we don't give users the way to express this
456 /// borrow, it's just used when translating closures.
459 /// Data is mutable and not aliasable.
461 /// True if this borrow arose from method-call auto-ref
462 /// (i.e. `adjustment::Adjust::Borrow`)
463 allow_two_phase_borrow: bool,
468 pub fn allows_two_phase_borrow(&self) -> bool {
470 BorrowKind::Shared | BorrowKind::Unique => false,
472 allow_two_phase_borrow,
473 } => allow_two_phase_borrow,
478 ///////////////////////////////////////////////////////////////////////////
479 // Variables and temps
483 DEBUG_FORMAT = "_{}",
484 const RETURN_PLACE = 0,
487 /// Classifies locals into categories. See `Mir::local_kind`.
488 #[derive(PartialEq, Eq, Debug)]
490 /// User-declared variable binding
492 /// Compiler-introduced temporary
494 /// Function argument
496 /// Location of function's return value
500 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
501 pub struct VarBindingForm {
502 /// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
503 pub binding_mode: ty::BindingMode,
504 /// If an explicit type was provided for this variable binding,
505 /// this holds the source Span of that type.
507 /// NOTE: If you want to change this to a `HirId`, be wary that
508 /// doing so breaks incremental compilation (as of this writing),
509 /// while a `Span` does not cause our tests to fail.
510 pub opt_ty_info: Option<Span>,
513 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
514 pub enum BindingForm {
515 /// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
517 /// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
521 CloneTypeFoldableAndLiftImpls! { BindingForm, }
523 impl_stable_hash_for!(struct self::VarBindingForm { binding_mode, opt_ty_info });
525 impl_stable_hash_for!(enum self::BindingForm { Var(binding), ImplicitSelf, });
529 /// This can be a binding declared by the user, a temporary inserted by the compiler, a function
530 /// argument, or the return place.
531 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
532 pub struct LocalDecl<'tcx> {
533 /// `let mut x` vs `let x`.
535 /// Temporaries and the return place are always mutable.
536 pub mutability: Mutability,
538 /// Some(binding_mode) if this corresponds to a user-declared local variable.
540 /// This is solely used for local diagnostics when generating
541 /// warnings/errors when compiling the current crate, and
542 /// therefore it need not be visible across crates. pnkfelix
543 /// currently hypothesized we *need* to wrap this in a
544 /// `ClearCrossCrate` as long as it carries as `HirId`.
545 pub is_user_variable: Option<ClearCrossCrate<BindingForm>>,
547 /// True if this is an internal local
549 /// These locals are not based on types in the source code and are only used
550 /// for a few desugarings at the moment.
552 /// The generator transformation will sanity check the locals which are live
553 /// across a suspension point against the type components of the generator
554 /// which type checking knows are live across a suspension point. We need to
555 /// flag drop flags to avoid triggering this check as they are introduced
558 /// Unsafety checking will also ignore dereferences of these locals,
559 /// so they can be used for raw pointers only used in a desugaring.
561 /// This should be sound because the drop flags are fully algebraic, and
562 /// therefore don't affect the OIBIT or outlives properties of the
566 /// Type of this local.
569 /// Name of the local, used in debuginfo and pretty-printing.
571 /// Note that function arguments can also have this set to `Some(_)`
572 /// to generate better debuginfo.
573 pub name: Option<Name>,
575 /// The *syntactic* (i.e. not visibility) source scope the local is defined
576 /// in. If the local was defined in a let-statement, this
577 /// is *within* the let-statement, rather than outside
580 /// This is needed because the visibility source scope of locals within
581 /// a let-statement is weird.
583 /// The reason is that we want the local to be *within* the let-statement
584 /// for lint purposes, but we want the local to be *after* the let-statement
585 /// for names-in-scope purposes.
587 /// That's it, if we have a let-statement like the one in this
591 /// fn foo(x: &str) {
592 /// #[allow(unused_mut)]
593 /// let mut x: u32 = { // <- one unused mut
594 /// let mut y: u32 = x.parse().unwrap();
601 /// Then, from a lint point of view, the declaration of `x: u32`
602 /// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
603 /// lint scopes are the same as the AST/HIR nesting.
605 /// However, from a name lookup point of view, the scopes look more like
606 /// as if the let-statements were `match` expressions:
609 /// fn foo(x: &str) {
611 /// match x.parse().unwrap() {
620 /// We care about the name-lookup scopes for debuginfo - if the
621 /// debuginfo instruction pointer is at the call to `x.parse()`, we
622 /// want `x` to refer to `x: &str`, but if it is at the call to
623 /// `drop(x)`, we want it to refer to `x: u32`.
625 /// To allow both uses to work, we need to have more than a single scope
626 /// for a local. We have the `source_info.scope` represent the
627 /// "syntactic" lint scope (with a variable being under its let
628 /// block) while the `visibility_scope` represents the "local variable"
629 /// scope (where the "rest" of a block is under all prior let-statements).
631 /// The end result looks like this:
635 /// │{ argument x: &str }
637 /// │ │{ #[allow(unused_mut] } // this is actually split into 2 scopes
638 /// │ │ // in practice because I'm lazy.
640 /// │ │← x.source_info.scope
641 /// │ │← `x.parse().unwrap()`
643 /// │ │ │← y.source_info.scope
645 /// │ │ │{ let y: u32 }
647 /// │ │ │← y.visibility_scope
650 /// │ │{ let x: u32 }
651 /// │ │← x.visibility_scope
652 /// │ │← `drop(x)` // this accesses `x: u32`
654 pub source_info: SourceInfo,
656 /// Source scope within which the local is visible (for debuginfo)
657 /// (see `source_info` for more details).
658 pub visibility_scope: SourceScope,
661 impl<'tcx> LocalDecl<'tcx> {
662 /// Returns true only if local is a binding that can itself be
663 /// made mutable via the addition of the `mut` keyword, namely
664 /// something like the occurrences of `x` in:
665 /// - `fn foo(x: Type) { ... }`,
667 /// - or `match ... { C(x) => ... }`
668 pub fn can_be_made_mutable(&self) -> bool {
669 match self.is_user_variable {
670 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
671 binding_mode: ty::BindingMode::BindByValue(_),
675 // FIXME: might be able to thread the distinction between
676 // `self`/`mut self`/`&self`/`&mut self` into the
677 // `BindingForm::ImplicitSelf` variant, (and then return
678 // true here for solely the first case).
683 /// Returns true if local is definitely not a `ref ident` or
684 /// `ref mut ident` binding. (Such bindings cannot be made into
685 /// mutable bindings, but the inverse does not necessarily hold).
686 pub fn is_nonref_binding(&self) -> bool {
687 match self.is_user_variable {
688 Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
689 binding_mode: ty::BindingMode::BindByValue(_),
693 Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf)) => true,
699 /// Create a new `LocalDecl` for a temporary.
701 pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
703 mutability: Mutability::Mut,
706 source_info: SourceInfo {
708 scope: OUTERMOST_SOURCE_SCOPE,
710 visibility_scope: OUTERMOST_SOURCE_SCOPE,
712 is_user_variable: None,
716 /// Create a new `LocalDecl` for a internal temporary.
718 pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
720 mutability: Mutability::Mut,
723 source_info: SourceInfo {
725 scope: OUTERMOST_SOURCE_SCOPE,
727 visibility_scope: OUTERMOST_SOURCE_SCOPE,
729 is_user_variable: None,
733 /// Builds a `LocalDecl` for the return place.
735 /// This must be inserted into the `local_decls` list as the first local.
737 pub fn new_return_place(return_ty: Ty, span: Span) -> LocalDecl {
739 mutability: Mutability::Mut,
741 source_info: SourceInfo {
743 scope: OUTERMOST_SOURCE_SCOPE,
745 visibility_scope: OUTERMOST_SOURCE_SCOPE,
747 name: None, // FIXME maybe we do want some name here?
748 is_user_variable: None,
753 /// A closure capture, with its name and mode.
754 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
755 pub struct UpvarDecl {
756 pub debug_name: Name,
758 /// If true, the capture is behind a reference.
761 pub mutability: Mutability,
764 ///////////////////////////////////////////////////////////////////////////
767 newtype_index!(BasicBlock { DEBUG_FORMAT = "bb{}" });
770 pub fn start_location(self) -> Location {
778 ///////////////////////////////////////////////////////////////////////////
779 // BasicBlockData and Terminator
781 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
782 pub struct BasicBlockData<'tcx> {
783 /// List of statements in this block.
784 pub statements: Vec<Statement<'tcx>>,
786 /// Terminator for this block.
788 /// NB. This should generally ONLY be `None` during construction.
789 /// Therefore, you should generally access it via the
790 /// `terminator()` or `terminator_mut()` methods. The only
791 /// exception is that certain passes, such as `simplify_cfg`, swap
792 /// out the terminator temporarily with `None` while they continue
793 /// to recurse over the set of basic blocks.
794 pub terminator: Option<Terminator<'tcx>>,
796 /// If true, this block lies on an unwind path. This is used
797 /// during codegen where distinct kinds of basic blocks may be
798 /// generated (particularly for MSVC cleanup). Unwind blocks must
799 /// only branch to other unwind blocks.
800 pub is_cleanup: bool,
803 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
804 pub struct Terminator<'tcx> {
805 pub source_info: SourceInfo,
806 pub kind: TerminatorKind<'tcx>,
809 #[derive(Clone, RustcEncodable, RustcDecodable)]
810 pub enum TerminatorKind<'tcx> {
811 /// block should have one successor in the graph; we jump there
812 Goto { target: BasicBlock },
814 /// operand evaluates to an integer; jump depending on its value
815 /// to one of the targets, and otherwise fallback to `otherwise`
817 /// discriminant value being tested
818 discr: Operand<'tcx>,
820 /// type of value being tested
823 /// Possible values. The locations to branch to in each case
824 /// are found in the corresponding indices from the `targets` vector.
825 values: Cow<'tcx, [u128]>,
827 /// Possible branch sites. The last element of this vector is used
828 /// for the otherwise branch, so targets.len() == values.len() + 1
830 // This invariant is quite non-obvious and also could be improved.
831 // One way to make this invariant is to have something like this instead:
833 // branches: Vec<(ConstInt, BasicBlock)>,
834 // otherwise: Option<BasicBlock> // exhaustive if None
836 // However we’ve decided to keep this as-is until we figure a case
837 // where some other approach seems to be strictly better than other.
838 targets: Vec<BasicBlock>,
841 /// Indicates that the landing pad is finished and unwinding should
842 /// continue. Emitted by build::scope::diverge_cleanup.
845 /// Indicates that the landing pad is finished and that the process
846 /// should abort. Used to prevent unwinding for foreign items.
849 /// Indicates a normal return. The return place should have
850 /// been filled in by now. This should occur at most once.
853 /// Indicates a terminator that can never be reached.
858 location: Place<'tcx>,
860 unwind: Option<BasicBlock>,
863 /// Drop the Place and assign the new value over it. This ensures
864 /// that the assignment to `P` occurs *even if* the destructor for
865 /// place unwinds. Its semantics are best explained by by the
870 /// DropAndReplace(P <- V, goto BB1, unwind BB2)
878 /// Drop(P, goto BB1, unwind BB2)
881 /// // P is now unitialized
885 /// // P is now unitialized -- its dtor panicked
890 location: Place<'tcx>,
891 value: Operand<'tcx>,
893 unwind: Option<BasicBlock>,
896 /// Block ends with a call of a converging function
898 /// The function that’s being called
900 /// Arguments the function is called with.
901 /// These are owned by the callee, which is free to modify them.
902 /// This allows the memory occupied by "by-value" arguments to be
903 /// reused across function calls without duplicating the contents.
904 args: Vec<Operand<'tcx>>,
905 /// Destination for the return value. If some, the call is converging.
906 destination: Option<(Place<'tcx>, BasicBlock)>,
907 /// Cleanups to be done if the call unwinds.
908 cleanup: Option<BasicBlock>,
911 /// Jump to the target if the condition has the expected value,
912 /// otherwise panic with a message and a cleanup target.
916 msg: AssertMessage<'tcx>,
918 cleanup: Option<BasicBlock>,
923 /// The value to return
924 value: Operand<'tcx>,
925 /// Where to resume to
927 /// Cleanup to be done if the generator is dropped at this suspend point
928 drop: Option<BasicBlock>,
931 /// Indicates the end of the dropping of a generator
934 /// A block where control flow only ever takes one real path, but borrowck
935 /// needs to be more conservative.
937 /// The target normal control flow will take
938 real_target: BasicBlock,
939 /// The list of blocks control flow could conceptually take, but won't
941 imaginary_targets: Vec<BasicBlock>,
943 /// A terminator for blocks that only take one path in reality, but where we
944 /// reserve the right to unwind in borrowck, even if it won't happen in practice.
945 /// This can arise in infinite loops with no function calls for example.
947 /// The target normal control flow will take
948 real_target: BasicBlock,
949 /// The imaginary cleanup block link. This particular path will never be taken
950 /// in practice, but in order to avoid fragility we want to always
951 /// consider it in borrowck. We don't want to accept programs which
952 /// pass borrowck only when panic=abort or some assertions are disabled
953 /// due to release vs. debug mode builds. This needs to be an Option because
954 /// of the remove_noop_landing_pads and no_landing_pads passes
955 unwind: Option<BasicBlock>,
959 pub type Successors<'a> =
960 iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
961 pub type SuccessorsMut<'a> =
962 iter::Chain<option::IntoIter<&'a mut BasicBlock>, slice::IterMut<'a, BasicBlock>>;
964 impl<'tcx> Terminator<'tcx> {
965 pub fn successors(&self) -> Successors {
966 self.kind.successors()
969 pub fn successors_mut(&mut self) -> SuccessorsMut {
970 self.kind.successors_mut()
973 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
974 self.kind.unwind_mut()
978 impl<'tcx> TerminatorKind<'tcx> {
979 pub fn if_<'a, 'gcx>(
980 tcx: TyCtxt<'a, 'gcx, 'tcx>,
984 ) -> TerminatorKind<'tcx> {
985 static BOOL_SWITCH_FALSE: &'static [u128] = &[0];
986 TerminatorKind::SwitchInt {
988 switch_ty: tcx.types.bool,
989 values: From::from(BOOL_SWITCH_FALSE),
994 pub fn successors(&self) -> Successors {
995 use self::TerminatorKind::*;
1006 } => None.into_iter().chain(&[]),
1007 Goto { target: ref t }
1010 cleanup: Some(ref t),
1014 destination: Some((_, ref t)),
1041 } => Some(t).into_iter().chain(&[]),
1043 destination: Some((_, ref t)),
1044 cleanup: Some(ref u),
1054 unwind: Some(ref u),
1059 unwind: Some(ref u),
1064 cleanup: Some(ref u),
1069 unwind: Some(ref u),
1070 } => Some(t).into_iter().chain(slice::from_ref(u)),
1071 SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]),
1074 ref imaginary_targets,
1075 } => Some(real_target).into_iter().chain(&imaginary_targets[..]),
1079 pub fn successors_mut(&mut self) -> SuccessorsMut {
1080 use self::TerminatorKind::*;
1091 } => None.into_iter().chain(&mut []),
1092 Goto { target: ref mut t }
1095 cleanup: Some(ref mut t),
1099 destination: Some((_, ref mut t)),
1124 real_target: ref mut t,
1126 } => Some(t).into_iter().chain(&mut []),
1128 destination: Some((_, ref mut t)),
1129 cleanup: Some(ref mut u),
1134 drop: Some(ref mut u),
1139 unwind: Some(ref mut u),
1144 unwind: Some(ref mut u),
1149 cleanup: Some(ref mut u),
1153 real_target: ref mut t,
1154 unwind: Some(ref mut u),
1155 } => Some(t).into_iter().chain(slice::from_mut(u)),
1158 } => None.into_iter().chain(&mut targets[..]),
1160 ref mut real_target,
1161 ref mut imaginary_targets,
1162 } => Some(real_target)
1164 .chain(&mut imaginary_targets[..]),
1168 pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
1170 TerminatorKind::Goto { .. }
1171 | TerminatorKind::Resume
1172 | TerminatorKind::Abort
1173 | TerminatorKind::Return
1174 | TerminatorKind::Unreachable
1175 | TerminatorKind::GeneratorDrop
1176 | TerminatorKind::Yield { .. }
1177 | TerminatorKind::SwitchInt { .. }
1178 | TerminatorKind::FalseEdges { .. } => None,
1179 TerminatorKind::Call {
1180 cleanup: ref mut unwind,
1183 | TerminatorKind::Assert {
1184 cleanup: ref mut unwind,
1187 | TerminatorKind::DropAndReplace { ref mut unwind, .. }
1188 | TerminatorKind::Drop { ref mut unwind, .. }
1189 | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind),
1194 impl<'tcx> BasicBlockData<'tcx> {
1195 pub fn new(terminator: Option<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
1203 /// Accessor for terminator.
1205 /// Terminator may not be None after construction of the basic block is complete. This accessor
1206 /// provides a convenience way to reach the terminator.
1207 pub fn terminator(&self) -> &Terminator<'tcx> {
1208 self.terminator.as_ref().expect("invalid terminator state")
1211 pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
1212 self.terminator.as_mut().expect("invalid terminator state")
1215 pub fn retain_statements<F>(&mut self, mut f: F)
1217 F: FnMut(&mut Statement) -> bool,
1219 for s in &mut self.statements {
1226 pub fn expand_statements<F, I>(&mut self, mut f: F)
1228 F: FnMut(&mut Statement<'tcx>) -> Option<I>,
1229 I: iter::TrustedLen<Item = Statement<'tcx>>,
1231 // Gather all the iterators we'll need to splice in, and their positions.
1232 let mut splices: Vec<(usize, I)> = vec![];
1233 let mut extra_stmts = 0;
1234 for (i, s) in self.statements.iter_mut().enumerate() {
1235 if let Some(mut new_stmts) = f(s) {
1236 if let Some(first) = new_stmts.next() {
1237 // We can already store the first new statement.
1240 // Save the other statements for optimized splicing.
1241 let remaining = new_stmts.size_hint().0;
1243 splices.push((i + 1 + extra_stmts, new_stmts));
1244 extra_stmts += remaining;
1252 // Splice in the new statements, from the end of the block.
1253 // FIXME(eddyb) This could be more efficient with a "gap buffer"
1254 // where a range of elements ("gap") is left uninitialized, with
1255 // splicing adding new elements to the end of that gap and moving
1256 // existing elements from before the gap to the end of the gap.
1257 // For now, this is safe code, emulating a gap but initializing it.
1258 let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
1259 self.statements.resize(
1262 source_info: SourceInfo {
1264 scope: OUTERMOST_SOURCE_SCOPE,
1266 kind: StatementKind::Nop,
1269 for (splice_start, new_stmts) in splices.into_iter().rev() {
1270 let splice_end = splice_start + new_stmts.size_hint().0;
1271 while gap.end > splice_end {
1274 self.statements.swap(gap.start, gap.end);
1276 self.statements.splice(splice_start..splice_end, new_stmts);
1277 gap.end = splice_start;
1281 pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
1282 if index < self.statements.len() {
1283 &self.statements[index]
1290 impl<'tcx> Debug for TerminatorKind<'tcx> {
1291 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1292 self.fmt_head(fmt)?;
1293 let successor_count = self.successors().count();
1294 let labels = self.fmt_successor_labels();
1295 assert_eq!(successor_count, labels.len());
1297 match successor_count {
1300 1 => write!(fmt, " -> {:?}", self.successors().nth(0).unwrap()),
1303 write!(fmt, " -> [")?;
1304 for (i, target) in self.successors().enumerate() {
1308 write!(fmt, "{}: {:?}", labels[i], target)?;
1316 impl<'tcx> TerminatorKind<'tcx> {
1317 /// Write the "head" part of the terminator; that is, its name and the data it uses to pick the
1318 /// successor basic block, if any. The only information not included is the list of possible
1319 /// successors, which may be rendered differently between the text and the graphviz format.
1320 pub fn fmt_head<W: Write>(&self, fmt: &mut W) -> fmt::Result {
1321 use self::TerminatorKind::*;
1323 Goto { .. } => write!(fmt, "goto"),
1325 discr: ref place, ..
1326 } => write!(fmt, "switchInt({:?})", place),
1327 Return => write!(fmt, "return"),
1328 GeneratorDrop => write!(fmt, "generator_drop"),
1329 Resume => write!(fmt, "resume"),
1330 Abort => write!(fmt, "abort"),
1331 Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
1332 Unreachable => write!(fmt, "unreachable"),
1333 Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
1338 } => write!(fmt, "replace({:?} <- {:?})", location, value),
1345 if let Some((ref destination, _)) = *destination {
1346 write!(fmt, "{:?} = ", destination)?;
1348 write!(fmt, "{:?}(", func)?;
1349 for (index, arg) in args.iter().enumerate() {
1353 write!(fmt, "{:?}", arg)?;
1363 write!(fmt, "assert(")?;
1367 write!(fmt, "{:?}, \"{:?}\")", cond, msg)
1369 FalseEdges { .. } => write!(fmt, "falseEdges"),
1370 FalseUnwind { .. } => write!(fmt, "falseUnwind"),
1374 /// Return the list of labels for the edges to the successor basic blocks.
1375 pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
1376 use self::TerminatorKind::*;
1378 Return | Resume | Abort | Unreachable | GeneratorDrop => vec![],
1379 Goto { .. } => vec!["".into()],
1385 let size = ty::tls::with(|tcx| {
1386 let param_env = ty::ParamEnv::empty();
1387 let switch_ty = tcx.lift_to_global(&switch_ty).unwrap();
1388 tcx.layout_of(param_env.and(switch_ty)).unwrap().size
1393 let mut s = String::new();
1395 Value::Scalar(Scalar::Bits {
1397 defined: size.bits() as u8,
1404 .chain(iter::once(String::from("otherwise").into()))
1408 destination: Some(_),
1411 } => vec!["return".into_cow(), "unwind".into_cow()],
1413 destination: Some(_),
1416 } => vec!["return".into_cow()],
1421 } => vec!["unwind".into_cow()],
1427 Yield { drop: Some(_), .. } => vec!["resume".into_cow(), "drop".into_cow()],
1428 Yield { drop: None, .. } => vec!["resume".into_cow()],
1429 DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => {
1430 vec!["return".into_cow()]
1437 } => vec!["return".into_cow(), "unwind".into_cow()],
1438 Assert { cleanup: None, .. } => vec!["".into()],
1439 Assert { .. } => vec!["success".into_cow(), "unwind".into_cow()],
1441 ref imaginary_targets,
1444 let mut l = vec!["real".into()];
1445 l.resize(imaginary_targets.len() + 1, "imaginary".into());
1450 } => vec!["real".into(), "cleanup".into()],
1451 FalseUnwind { unwind: None, .. } => vec!["real".into()],
1456 ///////////////////////////////////////////////////////////////////////////
1459 #[derive(Clone, RustcEncodable, RustcDecodable)]
1460 pub struct Statement<'tcx> {
1461 pub source_info: SourceInfo,
1462 pub kind: StatementKind<'tcx>,
1465 impl<'tcx> Statement<'tcx> {
1466 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
1467 /// invalidating statement indices in `Location`s.
1468 pub fn make_nop(&mut self) {
1469 self.kind = StatementKind::Nop
1472 /// Changes a statement to a nop and returns the original statement.
1473 pub fn replace_nop(&mut self) -> Self {
1475 source_info: self.source_info,
1476 kind: mem::replace(&mut self.kind, StatementKind::Nop),
1481 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1482 pub enum StatementKind<'tcx> {
1483 /// Write the RHS Rvalue to the LHS Place.
1484 Assign(Place<'tcx>, Rvalue<'tcx>),
1486 /// This represents all the reading that a pattern match may do
1487 /// (e.g. inspecting constants and discriminant values).
1488 ReadForMatch(Place<'tcx>),
1490 /// Write the discriminant for a variant to the enum Place.
1493 variant_index: usize,
1496 /// Start a live range for the storage of the local.
1499 /// End the current live range for the storage of the local.
1502 /// Execute a piece of inline Assembly.
1504 asm: Box<InlineAsm>,
1505 outputs: Vec<Place<'tcx>>,
1506 inputs: Vec<Operand<'tcx>>,
1509 /// Assert the given places to be valid inhabitants of their type. These statements are
1510 /// currently only interpreted by miri and only generated when "-Z mir-emit-validate" is passed.
1511 /// See <https://internals.rust-lang.org/t/types-as-contracts/5562/73> for more details.
1512 Validate(ValidationOp, Vec<ValidationOperand<'tcx, Place<'tcx>>>),
1514 /// Mark one terminating point of a region scope (i.e. static region).
1515 /// (The starting point(s) arise implicitly from borrows.)
1516 EndRegion(region::Scope),
1518 /// Encodes a user's type assertion. These need to be preserved intact so that NLL can respect
1519 /// them. For example:
1521 /// let (a, b): (T, U) = y;
1523 /// Here we would insert a `UserAssertTy<(T, U)>(y)` instruction to check that the type of `y`
1524 /// is the right thing.
1526 /// `CanonicalTy` is used to capture "inference variables" from the user's types. For example:
1528 /// let x: Vec<_> = ...;
1529 /// let y: &u32 = ...;
1531 /// would result in `Vec<?0>` and `&'?0 u32` respectively (where `?0` is a canonicalized
1533 UserAssertTy(CanonicalTy<'tcx>, Local),
1535 /// No-op. Useful for deleting instructions without affecting statement indices.
1539 /// The `ValidationOp` describes what happens with each of the operands of a
1540 /// `Validate` statement.
1541 #[derive(Copy, Clone, RustcEncodable, RustcDecodable, PartialEq, Eq)]
1542 pub enum ValidationOp {
1543 /// Recursively traverse the place following the type and validate that all type
1544 /// invariants are maintained. Furthermore, acquire exclusive/read-only access to the
1545 /// memory reachable from the place.
1547 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1550 /// Recursive traverse the *mutable* part of the type and relinquish all exclusive
1551 /// access *until* the given region ends. Then, access will be recovered.
1552 Suspend(region::Scope),
1555 impl Debug for ValidationOp {
1556 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1557 use self::ValidationOp::*;
1559 Acquire => write!(fmt, "Acquire"),
1560 Release => write!(fmt, "Release"),
1561 // (reuse lifetime rendering policy from ppaux.)
1562 Suspend(ref ce) => write!(fmt, "Suspend({})", ty::ReScope(*ce)),
1567 // This is generic so that it can be reused by miri
1568 #[derive(Clone, RustcEncodable, RustcDecodable)]
1569 pub struct ValidationOperand<'tcx, T> {
1572 pub re: Option<region::Scope>,
1573 pub mutbl: hir::Mutability,
1576 impl<'tcx, T: Debug> Debug for ValidationOperand<'tcx, T> {
1577 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1578 write!(fmt, "{:?}: {:?}", self.place, self.ty)?;
1579 if let Some(ce) = self.re {
1580 // (reuse lifetime rendering policy from ppaux.)
1581 write!(fmt, "/{}", ty::ReScope(ce))?;
1583 if let hir::MutImmutable = self.mutbl {
1584 write!(fmt, " (imm)")?;
1590 impl<'tcx> Debug for Statement<'tcx> {
1591 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1592 use self::StatementKind::*;
1594 Assign(ref place, ref rv) => write!(fmt, "{:?} = {:?}", place, rv),
1595 ReadForMatch(ref place) => write!(fmt, "ReadForMatch({:?})", place),
1596 // (reuse lifetime rendering policy from ppaux.)
1597 EndRegion(ref ce) => write!(fmt, "EndRegion({})", ty::ReScope(*ce)),
1598 Validate(ref op, ref places) => write!(fmt, "Validate({:?}, {:?})", op, places),
1599 StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
1600 StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
1604 } => write!(fmt, "discriminant({:?}) = {:?}", place, variant_index),
1609 } => write!(fmt, "asm!({:?} : {:?} : {:?})", asm, outputs, inputs),
1610 UserAssertTy(ref c_ty, ref local) => {
1611 write!(fmt, "UserAssertTy({:?}, {:?})", c_ty, local)
1613 Nop => write!(fmt, "nop"),
1618 ///////////////////////////////////////////////////////////////////////////
1621 /// A path to a value; something that can be evaluated without
1622 /// changing or disturbing program state.
1623 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1624 pub enum Place<'tcx> {
1628 /// static or static mut variable
1629 Static(Box<Static<'tcx>>),
1631 /// projection out of a place (access a field, deref a pointer, etc)
1632 Projection(Box<PlaceProjection<'tcx>>),
1635 /// The def-id of a static, along with its normalized type (which is
1636 /// stored to avoid requiring normalization when reading MIR).
1637 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1638 pub struct Static<'tcx> {
1643 impl_stable_hash_for!(struct Static<'tcx> {
1648 /// The `Projection` data structure defines things of the form `B.x`
1649 /// or `*B` or `B[index]`. Note that it is parameterized because it is
1650 /// shared between `Constant` and `Place`. See the aliases
1651 /// `PlaceProjection` etc below.
1652 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1653 pub struct Projection<'tcx, B, V, T> {
1655 pub elem: ProjectionElem<'tcx, V, T>,
1658 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1659 pub enum ProjectionElem<'tcx, V, T> {
1664 /// These indices are generated by slice patterns. Easiest to explain
1668 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
1669 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
1670 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
1671 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
1674 /// index or -index (in Python terms), depending on from_end
1676 /// thing being indexed must be at least this long
1678 /// counting backwards from end?
1682 /// These indices are generated by slice patterns.
1684 /// slice[from:-to] in Python terms.
1690 /// "Downcast" to a variant of an ADT. Currently, we only introduce
1691 /// this for ADTs with more than one variant. It may be better to
1692 /// just introduce it always, or always for enums.
1693 Downcast(&'tcx AdtDef, usize),
1696 /// Alias for projections as they appear in places, where the base is a place
1697 /// and the index is a local.
1698 pub type PlaceProjection<'tcx> = Projection<'tcx, Place<'tcx>, Local, Ty<'tcx>>;
1700 /// Alias for projections as they appear in places, where the base is a place
1701 /// and the index is a local.
1702 pub type PlaceElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
1704 newtype_index!(Field { DEBUG_FORMAT = "field[{}]" });
1706 impl<'tcx> Place<'tcx> {
1707 pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
1708 self.elem(ProjectionElem::Field(f, ty))
1711 pub fn deref(self) -> Place<'tcx> {
1712 self.elem(ProjectionElem::Deref)
1715 pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: usize) -> Place<'tcx> {
1716 self.elem(ProjectionElem::Downcast(adt_def, variant_index))
1719 pub fn index(self, index: Local) -> Place<'tcx> {
1720 self.elem(ProjectionElem::Index(index))
1723 pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
1724 Place::Projection(Box::new(PlaceProjection { base: self, elem }))
1728 impl<'tcx> Debug for Place<'tcx> {
1729 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1733 Local(id) => write!(fmt, "{:?}", id),
1734 Static(box self::Static { def_id, ty }) => write!(
1737 ty::tls::with(|tcx| tcx.item_path_str(def_id)),
1740 Projection(ref data) => match data.elem {
1741 ProjectionElem::Downcast(ref adt_def, index) => {
1742 write!(fmt, "({:?} as {})", data.base, adt_def.variants[index].name)
1744 ProjectionElem::Deref => write!(fmt, "(*{:?})", data.base),
1745 ProjectionElem::Field(field, ty) => {
1746 write!(fmt, "({:?}.{:?}: {:?})", data.base, field.index(), ty)
1748 ProjectionElem::Index(ref index) => write!(fmt, "{:?}[{:?}]", data.base, index),
1749 ProjectionElem::ConstantIndex {
1753 } => write!(fmt, "{:?}[{:?} of {:?}]", data.base, offset, min_length),
1754 ProjectionElem::ConstantIndex {
1758 } => write!(fmt, "{:?}[-{:?} of {:?}]", data.base, offset, min_length),
1759 ProjectionElem::Subslice { from, to } if to == 0 => {
1760 write!(fmt, "{:?}[{:?}:]", data.base, from)
1762 ProjectionElem::Subslice { from, to } if from == 0 => {
1763 write!(fmt, "{:?}[:-{:?}]", data.base, to)
1765 ProjectionElem::Subslice { from, to } => {
1766 write!(fmt, "{:?}[{:?}:-{:?}]", data.base, from, to)
1773 ///////////////////////////////////////////////////////////////////////////
1776 newtype_index!(SourceScope
1778 DEBUG_FORMAT = "scope[{}]",
1779 const OUTERMOST_SOURCE_SCOPE = 0,
1782 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1783 pub struct SourceScopeData {
1785 pub parent_scope: Option<SourceScope>,
1788 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
1789 pub struct SourceScopeLocalData {
1790 /// A NodeId with lint levels equivalent to this scope's lint levels.
1791 pub lint_root: ast::NodeId,
1792 /// The unsafe block that contains this node.
1796 ///////////////////////////////////////////////////////////////////////////
1799 /// These are values that can appear inside an rvalue (or an index
1800 /// place). They are intentionally limited to prevent rvalues from
1801 /// being nested in one another.
1802 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
1803 pub enum Operand<'tcx> {
1804 /// Copy: The value must be available for use afterwards.
1806 /// This implies that the type of the place must be `Copy`; this is true
1807 /// by construction during build, but also checked by the MIR type checker.
1809 /// Move: The value (including old borrows of it) will not be used again.
1811 /// Safe for values of all types (modulo future developments towards `?Move`).
1812 /// Correct usage patterns are enforced by the borrow checker for safe code.
1813 /// `Copy` may be converted to `Move` to enable "last-use" optimizations.
1815 Constant(Box<Constant<'tcx>>),
1818 impl<'tcx> Debug for Operand<'tcx> {
1819 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1820 use self::Operand::*;
1822 Constant(ref a) => write!(fmt, "{:?}", a),
1823 Copy(ref place) => write!(fmt, "{:?}", place),
1824 Move(ref place) => write!(fmt, "move {:?}", place),
1829 impl<'tcx> Operand<'tcx> {
1830 pub fn function_handle<'a>(
1831 tcx: TyCtxt<'a, 'tcx, 'tcx>,
1833 substs: &'tcx Substs<'tcx>,
1836 let ty = tcx.type_of(def_id).subst(tcx, substs);
1837 Operand::Constant(box Constant {
1840 literal: Literal::Value {
1841 value: ty::Const::zero_sized(tcx, ty),
1846 pub fn to_copy(&self) -> Self {
1848 Operand::Copy(_) | Operand::Constant(_) => self.clone(),
1849 Operand::Move(ref place) => Operand::Copy(place.clone()),
1854 ///////////////////////////////////////////////////////////////////////////
1857 #[derive(Clone, RustcEncodable, RustcDecodable)]
1858 pub enum Rvalue<'tcx> {
1859 /// x (either a move or copy, depending on type of x)
1863 Repeat(Operand<'tcx>, u64),
1866 Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
1868 /// length of a [X] or [X;n] value
1871 Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
1873 BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
1874 CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
1876 NullaryOp(NullOp, Ty<'tcx>),
1877 UnaryOp(UnOp, Operand<'tcx>),
1879 /// Read the discriminant of an ADT.
1881 /// Undefined (i.e. no effort is made to make it defined, but there’s no reason why it cannot
1882 /// be defined to return, say, a 0) if ADT is not an enum.
1883 Discriminant(Place<'tcx>),
1885 /// Create an aggregate value, like a tuple or struct. This is
1886 /// only needed because we want to distinguish `dest = Foo { x:
1887 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
1888 /// that `Foo` has a destructor. These rvalues can be optimized
1889 /// away after type-checking and before lowering.
1890 Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
1893 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1897 /// Convert unique, zero-sized type for a fn to fn()
1900 /// Convert non capturing closure to fn()
1903 /// Convert safe fn() to unsafe fn()
1906 /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
1907 /// codegen must figure out the details once full monomorphization
1908 /// is known. For example, this could be used to cast from a
1909 /// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<Trait>`
1910 /// (presuming `T: Trait`).
1914 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1915 pub enum AggregateKind<'tcx> {
1916 /// The type is of the element
1920 /// The second field is the variant index. It's equal to 0 for struct
1921 /// and union expressions. The fourth field is
1922 /// active field number and is present only for union expressions
1923 /// -- e.g. for a union expression `SomeUnion { c: .. }`, the
1924 /// active field index would identity the field `c`
1925 Adt(&'tcx AdtDef, usize, &'tcx Substs<'tcx>, Option<usize>),
1927 Closure(DefId, ClosureSubsts<'tcx>),
1928 Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
1931 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1933 /// The `+` operator (addition)
1935 /// The `-` operator (subtraction)
1937 /// The `*` operator (multiplication)
1939 /// The `/` operator (division)
1941 /// The `%` operator (modulus)
1943 /// The `^` operator (bitwise xor)
1945 /// The `&` operator (bitwise and)
1947 /// The `|` operator (bitwise or)
1949 /// The `<<` operator (shift left)
1951 /// The `>>` operator (shift right)
1953 /// The `==` operator (equality)
1955 /// The `<` operator (less than)
1957 /// The `<=` operator (less than or equal to)
1959 /// The `!=` operator (not equal to)
1961 /// The `>=` operator (greater than or equal to)
1963 /// The `>` operator (greater than)
1965 /// The `ptr.offset` operator
1970 pub fn is_checkable(self) -> bool {
1973 Add | Sub | Mul | Shl | Shr => true,
1979 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1981 /// Return the size of a value of that type
1983 /// Create a new uninitialized box for a value of that type
1987 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1989 /// The `!` operator for logical inversion
1991 /// The `-` operator for negation
1995 impl<'tcx> Debug for Rvalue<'tcx> {
1996 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
1997 use self::Rvalue::*;
2000 Use(ref place) => write!(fmt, "{:?}", place),
2001 Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
2002 Len(ref a) => write!(fmt, "Len({:?})", a),
2003 Cast(ref kind, ref place, ref ty) => {
2004 write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
2006 BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
2007 CheckedBinaryOp(ref op, ref a, ref b) => {
2008 write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
2010 UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
2011 Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
2012 NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
2013 Ref(region, borrow_kind, ref place) => {
2014 let kind_str = match borrow_kind {
2015 BorrowKind::Shared => "",
2016 BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
2019 // When printing regions, add trailing space if necessary.
2020 let region = if ppaux::verbose() || ppaux::identify_regions() {
2021 let mut region = format!("{}", region);
2022 if region.len() > 0 {
2027 // Do not even print 'static
2030 write!(fmt, "&{}{}{:?}", region, kind_str, place)
2033 Aggregate(ref kind, ref places) => {
2034 fn fmt_tuple(fmt: &mut Formatter, places: &[Operand]) -> fmt::Result {
2035 let mut tuple_fmt = fmt.debug_tuple("");
2036 for place in places {
2037 tuple_fmt.field(place);
2043 AggregateKind::Array(_) => write!(fmt, "{:?}", places),
2045 AggregateKind::Tuple => match places.len() {
2046 0 => write!(fmt, "()"),
2047 1 => write!(fmt, "({:?},)", places[0]),
2048 _ => fmt_tuple(fmt, places),
2051 AggregateKind::Adt(adt_def, variant, substs, _) => {
2052 let variant_def = &adt_def.variants[variant];
2054 ppaux::parameterized(fmt, substs, variant_def.did, &[])?;
2056 match variant_def.ctor_kind {
2057 CtorKind::Const => Ok(()),
2058 CtorKind::Fn => fmt_tuple(fmt, places),
2059 CtorKind::Fictive => {
2060 let mut struct_fmt = fmt.debug_struct("");
2061 for (field, place) in variant_def.fields.iter().zip(places) {
2062 struct_fmt.field(&field.ident.as_str(), place);
2069 AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
2070 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2071 let name = if tcx.sess.opts.debugging_opts.span_free_formats {
2072 format!("[closure@{:?}]", node_id)
2074 format!("[closure@{:?}]", tcx.hir.span(node_id))
2076 let mut struct_fmt = fmt.debug_struct(&name);
2078 tcx.with_freevars(node_id, |freevars| {
2079 for (freevar, place) in freevars.iter().zip(places) {
2080 let var_name = tcx.hir.name(freevar.var_id());
2081 struct_fmt.field(&var_name.as_str(), place);
2087 write!(fmt, "[closure]")
2091 AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
2092 if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
2093 let name = format!("[generator@{:?}]", tcx.hir.span(node_id));
2094 let mut struct_fmt = fmt.debug_struct(&name);
2096 tcx.with_freevars(node_id, |freevars| {
2097 for (freevar, place) in freevars.iter().zip(places) {
2098 let var_name = tcx.hir.name(freevar.var_id());
2099 struct_fmt.field(&var_name.as_str(), place);
2101 struct_fmt.field("$state", &places[freevars.len()]);
2102 for i in (freevars.len() + 1)..places.len() {
2104 .field(&format!("${}", i - freevars.len() - 1), &places[i]);
2110 write!(fmt, "[generator]")
2119 ///////////////////////////////////////////////////////////////////////////
2122 /// Two constants are equal if they are the same constant. Note that
2123 /// this does not necessarily mean that they are "==" in Rust -- in
2124 /// particular one must be wary of `NaN`!
2126 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2127 pub struct Constant<'tcx> {
2130 pub literal: Literal<'tcx>,
2133 newtype_index!(Promoted { DEBUG_FORMAT = "promoted[{}]" });
2135 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2136 pub enum Literal<'tcx> {
2138 value: &'tcx ty::Const<'tcx>,
2141 // Index into the `promoted` vector of `Mir`.
2146 impl<'tcx> Debug for Constant<'tcx> {
2147 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
2148 write!(fmt, "{:?}", self.literal)
2152 impl<'tcx> Debug for Literal<'tcx> {
2153 fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
2154 use self::Literal::*;
2156 Value { value } => {
2157 write!(fmt, "const ")?;
2158 fmt_const_val(fmt, value)
2160 Promoted { index } => write!(fmt, "{:?}", index),
2165 /// Write a `ConstVal` in a way closer to the original source code than the `Debug` output.
2166 pub fn fmt_const_val<W: Write>(fmt: &mut W, const_val: &ty::Const) -> fmt::Result {
2167 use middle::const_val::ConstVal;
2168 match const_val.val {
2169 ConstVal::Unevaluated(..) => write!(fmt, "{:?}", const_val),
2170 ConstVal::Value(val) => {
2171 if let Some(value) = val.to_byval_value() {
2172 print_miri_value(value, const_val.ty, fmt)
2174 write!(fmt, "{:?}:{}", val, const_val.ty)
2180 pub fn print_miri_value<W: Write>(value: Value, ty: Ty, f: &mut W) -> fmt::Result {
2181 use ty::TypeVariants::*;
2182 match (value, &ty.sty) {
2183 (Value::Scalar(Scalar::Bits { bits: 0, .. }), &TyBool) => write!(f, "false"),
2184 (Value::Scalar(Scalar::Bits { bits: 1, .. }), &TyBool) => write!(f, "true"),
2185 (Value::Scalar(Scalar::Bits { bits, .. }), &TyFloat(ast::FloatTy::F32)) => {
2186 write!(f, "{}f32", Single::from_bits(bits))
2188 (Value::Scalar(Scalar::Bits { bits, .. }), &TyFloat(ast::FloatTy::F64)) => {
2189 write!(f, "{}f64", Double::from_bits(bits))
2191 (Value::Scalar(Scalar::Bits { bits, .. }), &TyUint(ui)) => write!(f, "{:?}{}", bits, ui),
2192 (Value::Scalar(Scalar::Bits { bits, .. }), &TyInt(i)) => {
2193 let bit_width = ty::tls::with(|tcx| {
2194 let ty = tcx.lift_to_global(&ty).unwrap();
2195 tcx.layout_of(ty::ParamEnv::empty().and(ty))
2200 let shift = 128 - bit_width;
2201 write!(f, "{:?}{}", ((bits as i128) << shift) >> shift, i)
2203 (Value::Scalar(Scalar::Bits { bits, .. }), &TyChar) => {
2204 write!(f, "{:?}", ::std::char::from_u32(bits as u32).unwrap())
2206 (_, &TyFnDef(did, _)) => write!(f, "{}", item_path_str(did)),
2208 Value::ScalarPair(Scalar::Ptr(ptr), Scalar::Bits { bits: len, .. }),
2209 &TyRef(_, &ty::TyS { sty: TyStr, .. }, _),
2210 ) => ty::tls::with(|tcx| match tcx.alloc_map.lock().get(ptr.alloc_id) {
2211 Some(interpret::AllocType::Memory(alloc)) => {
2212 assert_eq!(len as usize as u128, len);
2213 let slice = &alloc.bytes[(ptr.offset.bytes() as usize)..][..(len as usize)];
2214 let s = ::std::str::from_utf8(slice).expect("non utf8 str from miri");
2215 write!(f, "{:?}", s)
2217 _ => write!(f, "pointer to erroneous constant {:?}, {:?}", ptr, len),
2219 _ => write!(f, "{:?}:{}", value, ty),
2223 fn item_path_str(def_id: DefId) -> String {
2224 ty::tls::with(|tcx| tcx.item_path_str(def_id))
2227 impl<'tcx> ControlFlowGraph for Mir<'tcx> {
2228 type Node = BasicBlock;
2230 fn num_nodes(&self) -> usize {
2231 self.basic_blocks.len()
2234 fn start_node(&self) -> Self::Node {
2238 fn predecessors<'graph>(
2241 ) -> <Self as GraphPredecessors<'graph>>::Iter {
2242 self.predecessors_for(node).clone().into_iter()
2244 fn successors<'graph>(
2247 ) -> <Self as GraphSuccessors<'graph>>::Iter {
2248 self.basic_blocks[node].terminator().successors().cloned()
2252 impl<'a, 'b> GraphPredecessors<'b> for Mir<'a> {
2253 type Item = BasicBlock;
2254 type Iter = IntoIter<BasicBlock>;
2257 impl<'a, 'b> GraphSuccessors<'b> for Mir<'a> {
2258 type Item = BasicBlock;
2259 type Iter = iter::Cloned<Successors<'b>>;
2262 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
2263 pub struct Location {
2264 /// the location is within this block
2265 pub block: BasicBlock,
2267 /// the location is the start of the statement; or, if `statement_index`
2268 /// == num-statements, then the start of the terminator.
2269 pub statement_index: usize,
2272 impl fmt::Debug for Location {
2273 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2274 write!(fmt, "{:?}[{}]", self.block, self.statement_index)
2279 pub const START: Location = Location {
2284 /// Returns the location immediately after this one within the enclosing block.
2286 /// Note that if this location represents a terminator, then the
2287 /// resulting location would be out of bounds and invalid.
2288 pub fn successor_within_block(&self) -> Location {
2291 statement_index: self.statement_index + 1,
2295 pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
2296 if self.block == other.block {
2297 self.statement_index <= other.statement_index
2299 dominators.is_dominated_by(other.block, self.block)
2304 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2305 pub enum UnsafetyViolationKind {
2307 ExternStatic(ast::NodeId),
2308 BorrowPacked(ast::NodeId),
2311 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2312 pub struct UnsafetyViolation {
2313 pub source_info: SourceInfo,
2314 pub description: InternedString,
2315 pub kind: UnsafetyViolationKind,
2318 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
2319 pub struct UnsafetyCheckResult {
2320 /// Violations that are propagated *upwards* from this function
2321 pub violations: Lrc<[UnsafetyViolation]>,
2322 /// unsafe blocks in this function, along with whether they are used. This is
2323 /// used for the "unused_unsafe" lint.
2324 pub unsafe_blocks: Lrc<[(ast::NodeId, bool)]>,
2327 /// The layout of generator state
2328 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2329 pub struct GeneratorLayout<'tcx> {
2330 pub fields: Vec<LocalDecl<'tcx>>,
2333 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2334 pub struct BorrowCheckResult<'gcx> {
2335 pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
2336 pub used_mut_upvars: SmallVec<[Field; 8]>,
2339 /// After we borrow check a closure, we are left with various
2340 /// requirements that we have inferred between the free regions that
2341 /// appear in the closure's signature or on its field types. These
2342 /// requirements are then verified and proved by the closure's
2343 /// creating function. This struct encodes those requirements.
2345 /// The requirements are listed as being between various
2346 /// `RegionVid`. The 0th region refers to `'static`; subsequent region
2347 /// vids refer to the free regions that appear in the closure (or
2348 /// generator's) type, in order of appearance. (This numbering is
2349 /// actually defined by the `UniversalRegions` struct in the NLL
2350 /// region checker. See for example
2351 /// `UniversalRegions::closure_mapping`.) Note that we treat the free
2352 /// regions in the closure's type "as if" they were erased, so their
2353 /// precise identity is not important, only their position.
2355 /// Example: If type check produces a closure with the closure substs:
2358 /// ClosureSubsts = [
2359 /// i8, // the "closure kind"
2360 /// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
2361 /// &'a String, // some upvar
2365 /// here, there is one unique free region (`'a`) but it appears
2366 /// twice. We would "renumber" each occurrence to a unique vid, as follows:
2369 /// ClosureSubsts = [
2370 /// i8, // the "closure kind"
2371 /// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
2372 /// &'2 String, // some upvar
2376 /// Now the code might impose a requirement like `'1: '2`. When an
2377 /// instance of the closure is created, the corresponding free regions
2378 /// can be extracted from its type and constrained to have the given
2379 /// outlives relationship.
2381 /// In some cases, we have to record outlives requirements between
2382 /// types and regions as well. In that case, if those types include
2383 /// any regions, those regions are recorded as `ReClosureBound`
2384 /// instances assigned one of these same indices. Those regions will
2385 /// be substituted away by the creator. We use `ReClosureBound` in
2386 /// that case because the regions must be allocated in the global
2387 /// TyCtxt, and hence we cannot use `ReVar` (which is what we use
2388 /// internally within the rest of the NLL code).
2389 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
2390 pub struct ClosureRegionRequirements<'gcx> {
2391 /// The number of external regions defined on the closure. In our
2392 /// example above, it would be 3 -- one for `'static`, then `'1`
2393 /// and `'2`. This is just used for a sanity check later on, to
2394 /// make sure that the number of regions we see at the callsite
2396 pub num_external_vids: usize,
2398 /// Requirements between the various free regions defined in
2400 pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
2403 /// Indicates an outlives constraint between a type or between two
2404 /// free-regions declared on the closure.
2405 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2406 pub struct ClosureOutlivesRequirement<'tcx> {
2407 // This region or type ...
2408 pub subject: ClosureOutlivesSubject<'tcx>,
2410 // .. must outlive this one.
2411 pub outlived_free_region: ty::RegionVid,
2413 // If not, report an error here.
2414 pub blame_span: Span,
2417 /// The subject of a ClosureOutlivesRequirement -- that is, the thing
2418 /// that must outlive some region.
2419 #[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
2420 pub enum ClosureOutlivesSubject<'tcx> {
2421 /// Subject is a type, typically a type parameter, but could also
2422 /// be a projection. Indicates a requirement like `T: 'a` being
2423 /// passed to the caller, where the type here is `T`.
2425 /// The type here is guaranteed not to contain any free regions at
2429 /// Subject is a free region from the closure. Indicates a requirement
2430 /// like `'a: 'b` being passed to the caller; the region here is `'a`.
2431 Region(ty::RegionVid),
2435 * TypeFoldable implementations for MIR types
2438 CloneTypeFoldableAndLiftImpls! {
2445 SourceScopeLocalData,
2448 BraceStructTypeFoldableImpl! {
2449 impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
2452 source_scope_local_data,
2466 BraceStructTypeFoldableImpl! {
2467 impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
2472 BraceStructTypeFoldableImpl! {
2473 impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
2484 BraceStructTypeFoldableImpl! {
2485 impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
2492 BraceStructTypeFoldableImpl! {
2493 impl<'tcx> TypeFoldable<'tcx> for ValidationOperand<'tcx, Place<'tcx>> {
2494 place, ty, re, mutbl
2498 BraceStructTypeFoldableImpl! {
2499 impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
2504 EnumTypeFoldableImpl! {
2505 impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
2506 (StatementKind::Assign)(a, b),
2507 (StatementKind::ReadForMatch)(place),
2508 (StatementKind::SetDiscriminant) { place, variant_index },
2509 (StatementKind::StorageLive)(a),
2510 (StatementKind::StorageDead)(a),
2511 (StatementKind::InlineAsm) { asm, outputs, inputs },
2512 (StatementKind::Validate)(a, b),
2513 (StatementKind::EndRegion)(a),
2514 (StatementKind::UserAssertTy)(a, b),
2515 (StatementKind::Nop),
2519 EnumTypeFoldableImpl! {
2520 impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
2521 (ClearCrossCrate::Clear),
2522 (ClearCrossCrate::Set)(a),
2523 } where T: TypeFoldable<'tcx>
2526 impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
2527 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2528 use mir::TerminatorKind::*;
2530 let kind = match self.kind {
2531 Goto { target } => Goto { target: target },
2538 discr: discr.fold_with(folder),
2539 switch_ty: switch_ty.fold_with(folder),
2540 values: values.clone(),
2541 targets: targets.clone(),
2548 location: location.fold_with(folder),
2557 } => DropAndReplace {
2558 location: location.fold_with(folder),
2559 value: value.fold_with(folder),
2568 value: value.fold_with(folder),
2578 let dest = destination
2580 .map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
2583 func: func.fold_with(folder),
2584 args: args.fold_with(folder),
2596 let msg = if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2597 EvalErrorKind::BoundsCheck {
2598 len: len.fold_with(folder),
2599 index: index.fold_with(folder),
2605 cond: cond.fold_with(folder),
2612 GeneratorDrop => GeneratorDrop,
2616 Unreachable => Unreachable,
2619 ref imaginary_targets,
2622 imaginary_targets: imaginary_targets.clone(),
2633 source_info: self.source_info,
2638 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2639 use mir::TerminatorKind::*;
2646 } => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
2647 Drop { ref location, .. } => location.visit_with(visitor),
2652 } => location.visit_with(visitor) || value.visit_with(visitor),
2653 Yield { ref value, .. } => value.visit_with(visitor),
2660 let dest = if let Some((ref loc, _)) = *destination {
2661 loc.visit_with(visitor)
2665 dest || func.visit_with(visitor) || args.visit_with(visitor)
2668 ref cond, ref msg, ..
2670 if cond.visit_with(visitor) {
2671 if let EvalErrorKind::BoundsCheck { ref len, ref index } = *msg {
2672 len.visit_with(visitor) || index.visit_with(visitor)
2687 | FalseUnwind { .. } => false,
2692 impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
2693 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2695 &Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
2700 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2701 if let &Place::Projection(ref p) = self {
2702 p.visit_with(visitor)
2709 impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
2710 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2713 Use(ref op) => Use(op.fold_with(folder)),
2714 Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
2715 Ref(region, bk, ref place) => {
2716 Ref(region.fold_with(folder), bk, place.fold_with(folder))
2718 Len(ref place) => Len(place.fold_with(folder)),
2719 Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
2720 BinaryOp(op, ref rhs, ref lhs) => {
2721 BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2723 CheckedBinaryOp(op, ref rhs, ref lhs) => {
2724 CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
2726 UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
2727 Discriminant(ref place) => Discriminant(place.fold_with(folder)),
2728 NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
2729 Aggregate(ref kind, ref fields) => {
2730 let kind = box match **kind {
2731 AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
2732 AggregateKind::Tuple => AggregateKind::Tuple,
2733 AggregateKind::Adt(def, v, substs, n) => {
2734 AggregateKind::Adt(def, v, substs.fold_with(folder), n)
2736 AggregateKind::Closure(id, substs) => {
2737 AggregateKind::Closure(id, substs.fold_with(folder))
2739 AggregateKind::Generator(id, substs, movablity) => {
2740 AggregateKind::Generator(id, substs.fold_with(folder), movablity)
2743 Aggregate(kind, fields.fold_with(folder))
2748 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2751 Use(ref op) => op.visit_with(visitor),
2752 Repeat(ref op, _) => op.visit_with(visitor),
2753 Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
2754 Len(ref place) => place.visit_with(visitor),
2755 Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
2756 BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
2757 rhs.visit_with(visitor) || lhs.visit_with(visitor)
2759 UnaryOp(_, ref val) => val.visit_with(visitor),
2760 Discriminant(ref place) => place.visit_with(visitor),
2761 NullaryOp(_, ty) => ty.visit_with(visitor),
2762 Aggregate(ref kind, ref fields) => {
2764 AggregateKind::Array(ty) => ty.visit_with(visitor),
2765 AggregateKind::Tuple => false,
2766 AggregateKind::Adt(_, _, substs, _) => substs.visit_with(visitor),
2767 AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
2768 AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
2769 }) || fields.visit_with(visitor)
2775 impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
2776 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2778 Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
2779 Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
2780 Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
2784 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2786 Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
2787 Operand::Constant(ref c) => c.visit_with(visitor),
2792 impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<'tcx, B, V, T>
2794 B: TypeFoldable<'tcx>,
2795 V: TypeFoldable<'tcx>,
2796 T: TypeFoldable<'tcx>,
2798 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2799 use mir::ProjectionElem::*;
2801 let base = self.base.fold_with(folder);
2802 let elem = match self.elem {
2804 Field(f, ref ty) => Field(f, ty.fold_with(folder)),
2805 Index(ref v) => Index(v.fold_with(folder)),
2806 ref elem => elem.clone(),
2809 Projection { base, elem }
2812 fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
2813 use mir::ProjectionElem::*;
2815 self.base.visit_with(visitor) || match self.elem {
2816 Field(_, ref ty) => ty.visit_with(visitor),
2817 Index(ref v) => v.visit_with(visitor),
2823 impl<'tcx> TypeFoldable<'tcx> for Field {
2824 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
2827 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
2832 impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
2833 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2835 span: self.span.clone(),
2836 ty: self.ty.fold_with(folder),
2837 literal: self.literal.fold_with(folder),
2840 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2841 self.ty.visit_with(visitor) || self.literal.visit_with(visitor)
2845 impl<'tcx> TypeFoldable<'tcx> for Literal<'tcx> {
2846 fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
2848 Literal::Value { value } => Literal::Value {
2849 value: value.fold_with(folder),
2851 Literal::Promoted { index } => Literal::Promoted { index },
2854 fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
2856 Literal::Value { value } => value.visit_with(visitor),
2857 Literal::Promoted { .. } => false,