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 use graphviz
::IntoCow
;
12 use middle
::const_val
::ConstVal
;
13 use rustc_const_math
::{ConstUsize, ConstInt, ConstMathErr}
;
14 use rustc_data_structures
::indexed_vec
::{IndexVec, Idx}
;
15 use rustc_data_structures
::control_flow_graph
::dominators
::{Dominators, dominators}
;
16 use rustc_data_structures
::control_flow_graph
::{GraphPredecessors, GraphSuccessors}
;
17 use rustc_data_structures
::control_flow_graph
::ControlFlowGraph
;
18 use hir
::def_id
::DefId
;
19 use ty
::subst
::Substs
;
20 use ty
::{self, AdtDef, ClosureSubsts, Region, Ty}
;
22 use rustc_back
::slice
;
25 use std
::borrow
::{Cow}
;
27 use std
::fmt
::{self, Debug, Formatter, Write}
;
29 use std
::ops
::{Index, IndexMut}
;
30 use std
::vec
::IntoIter
;
31 use syntax
::ast
::{self, Name}
;
34 use super::cache
::Cache
;
36 macro_rules
! newtype_index
{
37 ($name
:ident
, $debug_name
:expr
) => (
38 #[derive(Copy, Clone, PartialEq, Eq, Hash, PartialOrd, Ord,
39 RustcEncodable
, RustcDecodable
)]
40 pub struct $
name(u32);
43 fn new(value
: usize) -> Self {
44 assert
!(value
< (u32::MAX
) as usize);
47 fn index(self) -> usize {
52 impl Debug
for $name
{
53 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
54 write
!(fmt
, "{}{}", $debug_name
, self.0)
60 /// Lowered representation of a single function.
61 #[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
62 pub struct Mir
<'tcx
> {
63 /// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
64 /// that indexes into this vector.
65 basic_blocks
: IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>>,
67 /// List of visibility (lexical) scopes; these are referenced by statements
68 /// and used (eventually) for debuginfo. Indexed by a `VisibilityScope`.
69 pub visibility_scopes
: IndexVec
<VisibilityScope
, VisibilityScopeData
>,
71 /// Rvalues promoted from this function, such as borrows of constants.
72 /// Each of them is the Mir of a constant with the fn's type parameters
73 /// in scope, but no vars or args and a separate set of temps.
74 pub promoted
: IndexVec
<Promoted
, Mir
<'tcx
>>,
76 /// Return type of the function.
77 pub return_ty
: Ty
<'tcx
>,
79 /// Variables: these are stack slots corresponding to user variables. They may be
80 /// assigned many times.
81 pub var_decls
: IndexVec
<Var
, VarDecl
<'tcx
>>,
83 /// Args: these are stack slots corresponding to the input arguments.
84 pub arg_decls
: IndexVec
<Arg
, ArgDecl
<'tcx
>>,
86 /// Temp declarations: stack slots that for temporaries created by
87 /// the compiler. These are assigned once, but they are not SSA
88 /// values in that it is possible to borrow them and mutate them
89 /// through the resulting reference.
90 pub temp_decls
: IndexVec
<Temp
, TempDecl
<'tcx
>>,
92 /// Names and capture modes of all the closure upvars, assuming
93 /// the first argument is either the closure or a reference to it.
94 pub upvar_decls
: Vec
<UpvarDecl
>,
96 /// A span representing this MIR, for error reporting
99 /// A cache for various calculations
103 /// where execution begins
104 pub const START_BLOCK
: BasicBlock
= BasicBlock(0);
106 impl<'tcx
> Mir
<'tcx
> {
107 pub fn new(basic_blocks
: IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>>,
108 visibility_scopes
: IndexVec
<VisibilityScope
, VisibilityScopeData
>,
109 promoted
: IndexVec
<Promoted
, Mir
<'tcx
>>,
111 var_decls
: IndexVec
<Var
, VarDecl
<'tcx
>>,
112 arg_decls
: IndexVec
<Arg
, ArgDecl
<'tcx
>>,
113 temp_decls
: IndexVec
<Temp
, TempDecl
<'tcx
>>,
114 upvar_decls
: Vec
<UpvarDecl
>,
118 basic_blocks
: basic_blocks
,
119 visibility_scopes
: visibility_scopes
,
121 return_ty
: return_ty
,
122 var_decls
: var_decls
,
123 arg_decls
: arg_decls
,
124 temp_decls
: temp_decls
,
125 upvar_decls
: upvar_decls
,
132 pub fn basic_blocks(&self) -> &IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>> {
137 pub fn basic_blocks_mut(&mut self) -> &mut IndexVec
<BasicBlock
, BasicBlockData
<'tcx
>> {
138 self.cache
.invalidate();
139 &mut self.basic_blocks
143 pub fn predecessors(&self) -> Ref
<IndexVec
<BasicBlock
, Vec
<BasicBlock
>>> {
144 self.cache
.predecessors(self)
148 pub fn predecessors_for(&self, bb
: BasicBlock
) -> Ref
<Vec
<BasicBlock
>> {
149 Ref
::map(self.predecessors(), |p
| &p
[bb
])
153 pub fn dominators(&self) -> Dominators
<BasicBlock
> {
157 /// Maps locals (Arg's, Var's, Temp's and ReturnPointer, in that order)
158 /// to their index in the whole list of locals. This is useful if you
159 /// want to treat all locals the same instead of repeating yourself.
160 pub fn local_index(&self, lvalue
: &Lvalue
<'tcx
>) -> Option
<Local
> {
161 let idx
= match *lvalue
{
162 Lvalue
::Arg(arg
) => arg
.index(),
163 Lvalue
::Var(var
) => {
164 self.arg_decls
.len() +
167 Lvalue
::Temp(temp
) => {
168 self.arg_decls
.len() +
169 self.var_decls
.len() +
172 Lvalue
::ReturnPointer
=> {
173 self.arg_decls
.len() +
174 self.var_decls
.len() +
175 self.temp_decls
.len()
178 Lvalue
::Projection(_
) => return None
180 Some(Local
::new(idx
))
183 /// Counts the number of locals, such that local_index
184 /// will always return an index smaller than this count.
185 pub fn count_locals(&self) -> usize {
186 self.arg_decls
.len() +
187 self.var_decls
.len() +
188 self.temp_decls
.len() + 1
191 pub fn format_local(&self, local
: Local
) -> String
{
192 let mut index
= local
.index();
193 index
= match index
.checked_sub(self.arg_decls
.len()) {
194 None
=> return format
!("{:?}", Arg
::new(index
)),
195 Some(index
) => index
,
197 index
= match index
.checked_sub(self.var_decls
.len()) {
198 None
=> return format
!("{:?}", Var
::new(index
)),
199 Some(index
) => index
,
201 index
= match index
.checked_sub(self.temp_decls
.len()) {
202 None
=> return format
!("{:?}", Temp
::new(index
)),
203 Some(index
) => index
,
205 debug_assert
!(index
== 0);
206 return "ReturnPointer".to_string()
209 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
210 /// invalidating statement indices in `Location`s.
211 pub fn make_statement_nop(&mut self, location
: Location
) {
212 let block
= &mut self[location
.block
];
213 debug_assert
!(location
.statement_index
< block
.statements
.len());
214 block
.statements
[location
.statement_index
].make_nop()
218 impl<'tcx
> Index
<BasicBlock
> for Mir
<'tcx
> {
219 type Output
= BasicBlockData
<'tcx
>;
222 fn index(&self, index
: BasicBlock
) -> &BasicBlockData
<'tcx
> {
223 &self.basic_blocks()[index
]
227 impl<'tcx
> IndexMut
<BasicBlock
> for Mir
<'tcx
> {
229 fn index_mut(&mut self, index
: BasicBlock
) -> &mut BasicBlockData
<'tcx
> {
230 &mut self.basic_blocks_mut()[index
]
234 /// Grouped information about the source code origin of a MIR entity.
235 /// Intended to be inspected by diagnostics and debuginfo.
236 /// Most passes can work with it as a whole, within a single function.
237 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
238 pub struct SourceInfo
{
239 /// Source span for the AST pertaining to this MIR entity.
242 /// The lexical visibility scope, i.e. which bindings can be seen.
243 pub scope
: VisibilityScope
246 ///////////////////////////////////////////////////////////////////////////
247 // Mutability and borrow kinds
249 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
250 pub enum Mutability
{
255 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
256 pub enum BorrowKind
{
257 /// Data must be immutable and is aliasable.
260 /// Data must be immutable but not aliasable. This kind of borrow
261 /// cannot currently be expressed by the user and is used only in
262 /// implicit closure bindings. It is needed when you the closure
263 /// is borrowing or mutating a mutable referent, e.g.:
265 /// let x: &mut isize = ...;
266 /// let y = || *x += 5;
268 /// If we were to try to translate this closure into a more explicit
269 /// form, we'd encounter an error with the code as written:
271 /// struct Env { x: & &mut isize }
272 /// let x: &mut isize = ...;
273 /// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
274 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
276 /// This is then illegal because you cannot mutate a `&mut` found
277 /// in an aliasable location. To solve, you'd have to translate with
278 /// an `&mut` borrow:
280 /// struct Env { x: & &mut isize }
281 /// let x: &mut isize = ...;
282 /// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
283 /// fn fn_ptr(env: &mut Env) { **env.x += 5; }
285 /// Now the assignment to `**env.x` is legal, but creating a
286 /// mutable pointer to `x` is not because `x` is not mutable. We
287 /// could fix this by declaring `x` as `let mut x`. This is ok in
288 /// user code, if awkward, but extra weird for closures, since the
289 /// borrow is hidden.
291 /// So we introduce a "unique imm" borrow -- the referent is
292 /// immutable, but not aliasable. This solves the problem. For
293 /// simplicity, we don't give users the way to express this
294 /// borrow, it's just used when translating closures.
297 /// Data is mutable and not aliasable.
301 ///////////////////////////////////////////////////////////////////////////
302 // Variables and temps
304 /// A "variable" is a binding declared by the user as part of the fn
305 /// decl, a let, etc.
306 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
307 pub struct VarDecl
<'tcx
> {
308 /// `let mut x` vs `let x`
309 pub mutability
: Mutability
,
311 /// name that user gave the variable; not that, internally,
312 /// mir references variables by index
315 /// type inferred for this variable (`let x: ty = ...`)
318 /// source information (span, scope, etc.) for the declaration
319 pub source_info
: SourceInfo
,
322 /// A "temp" is a temporary that we place on the stack. They are
323 /// anonymous, always mutable, and have only a type.
324 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
325 pub struct TempDecl
<'tcx
> {
329 /// A "arg" is one of the function's formal arguments. These are
330 /// anonymous and distinct from the bindings that the user declares.
332 /// For example, in this function:
335 /// fn foo((x, y): (i32, u32)) { ... }
338 /// there is only one argument, of type `(i32, u32)`, but two bindings
340 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
341 pub struct ArgDecl
<'tcx
> {
344 /// If true, this argument is a tuple after monomorphization,
345 /// and has to be collected from multiple actual arguments.
348 /// Either keywords::Invalid or the name of a single-binding
349 /// pattern associated with this argument. Useful for debuginfo.
353 /// A closure capture, with its name and mode.
354 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
355 pub struct UpvarDecl
{
356 pub debug_name
: Name
,
358 /// If true, the capture is behind a reference.
362 ///////////////////////////////////////////////////////////////////////////
365 newtype_index
!(BasicBlock
, "bb");
367 ///////////////////////////////////////////////////////////////////////////
368 // BasicBlockData and Terminator
370 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
371 pub struct BasicBlockData
<'tcx
> {
372 /// List of statements in this block.
373 pub statements
: Vec
<Statement
<'tcx
>>,
375 /// Terminator for this block.
377 /// NB. This should generally ONLY be `None` during construction.
378 /// Therefore, you should generally access it via the
379 /// `terminator()` or `terminator_mut()` methods. The only
380 /// exception is that certain passes, such as `simplify_cfg`, swap
381 /// out the terminator temporarily with `None` while they continue
382 /// to recurse over the set of basic blocks.
383 pub terminator
: Option
<Terminator
<'tcx
>>,
385 /// If true, this block lies on an unwind path. This is used
386 /// during trans where distinct kinds of basic blocks may be
387 /// generated (particularly for MSVC cleanup). Unwind blocks must
388 /// only branch to other unwind blocks.
389 pub is_cleanup
: bool
,
392 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
393 pub struct Terminator
<'tcx
> {
394 pub source_info
: SourceInfo
,
395 pub kind
: TerminatorKind
<'tcx
>
398 #[derive(Clone, RustcEncodable, RustcDecodable)]
399 pub enum TerminatorKind
<'tcx
> {
400 /// block should have one successor in the graph; we jump there
405 /// jump to branch 0 if this lvalue evaluates to true
408 targets
: (BasicBlock
, BasicBlock
),
411 /// lvalue evaluates to some enum; jump depending on the branch
414 adt_def
: AdtDef
<'tcx
>,
415 targets
: Vec
<BasicBlock
>,
418 /// operand evaluates to an integer; jump depending on its value
419 /// to one of the targets, and otherwise fallback to `otherwise`
421 /// discriminant value being tested
424 /// type of value being tested
427 /// Possible values. The locations to branch to in each case
428 /// are found in the corresponding indices from the `targets` vector.
429 values
: Vec
<ConstVal
>,
431 /// Possible branch sites. The length of this vector should be
432 /// equal to the length of the `values` vector plus 1 -- the
433 /// extra item is the block to branch to if none of the values
435 targets
: Vec
<BasicBlock
>,
438 /// Indicates that the landing pad is finished and unwinding should
439 /// continue. Emitted by build::scope::diverge_cleanup.
442 /// Indicates a normal return. The ReturnPointer lvalue should
443 /// have been filled in by now. This should occur at most once.
446 /// Indicates a terminator that can never be reached.
451 location
: Lvalue
<'tcx
>,
453 unwind
: Option
<BasicBlock
>
456 /// Drop the Lvalue and assign the new value over it
458 location
: Lvalue
<'tcx
>,
459 value
: Operand
<'tcx
>,
461 unwind
: Option
<BasicBlock
>,
464 /// Block ends with a call of a converging function
466 /// The function that’s being called
468 /// Arguments the function is called with
469 args
: Vec
<Operand
<'tcx
>>,
470 /// Destination for the return value. If some, the call is converging.
471 destination
: Option
<(Lvalue
<'tcx
>, BasicBlock
)>,
472 /// Cleanups to be done if the call unwinds.
473 cleanup
: Option
<BasicBlock
>
476 /// Jump to the target if the condition has the expected value,
477 /// otherwise panic with a message and a cleanup target.
481 msg
: AssertMessage
<'tcx
>,
483 cleanup
: Option
<BasicBlock
>
487 impl<'tcx
> Terminator
<'tcx
> {
488 pub fn successors(&self) -> Cow
<[BasicBlock
]> {
489 self.kind
.successors()
492 pub fn successors_mut(&mut self) -> Vec
<&mut BasicBlock
> {
493 self.kind
.successors_mut()
497 impl<'tcx
> TerminatorKind
<'tcx
> {
498 pub fn successors(&self) -> Cow
<[BasicBlock
]> {
499 use self::TerminatorKind
::*;
501 Goto { target: ref b }
=> slice
::ref_slice(b
).into_cow(),
502 If { targets: (b1, b2), .. }
=> vec
![b1
, b2
].into_cow(),
503 Switch { targets: ref b, .. }
=> b
[..].into_cow(),
504 SwitchInt { targets: ref b, .. }
=> b
[..].into_cow(),
505 Resume
=> (&[]).into_cow(),
506 Return
=> (&[]).into_cow(),
507 Unreachable
=> (&[]).into_cow(),
508 Call { destination: Some((_, t)), cleanup: Some(c), .. }
=> vec
![t
, c
].into_cow(),
509 Call { destination: Some((_, ref t)), cleanup: None, .. }
=>
510 slice
::ref_slice(t
).into_cow(),
511 Call { destination: None, cleanup: Some(ref c), .. }
=> slice
::ref_slice(c
).into_cow(),
512 Call { destination: None, cleanup: None, .. }
=> (&[]).into_cow(),
513 DropAndReplace { target, unwind: Some(unwind), .. }
|
514 Drop { target, unwind: Some(unwind), .. }
=> {
515 vec
![target
, unwind
].into_cow()
517 DropAndReplace { ref target, unwind: None, .. }
|
518 Drop { ref target, unwind: None, .. }
=> {
519 slice
::ref_slice(target
).into_cow()
521 Assert { target, cleanup: Some(unwind), .. }
=> vec
![target
, unwind
].into_cow(),
522 Assert { ref target, .. }
=> slice
::ref_slice(target
).into_cow(),
526 // FIXME: no mootable cow. I’m honestly not sure what a “cow” between `&mut [BasicBlock]` and
527 // `Vec<&mut BasicBlock>` would look like in the first place.
528 pub fn successors_mut(&mut self) -> Vec
<&mut BasicBlock
> {
529 use self::TerminatorKind
::*;
531 Goto { target: ref mut b }
=> vec
![b
],
532 If { targets: (ref mut b1, ref mut b2), .. }
=> vec
![b1
, b2
],
533 Switch { targets: ref mut b, .. }
=> b
.iter_mut().collect(),
534 SwitchInt { targets: ref mut b, .. }
=> b
.iter_mut().collect(),
535 Resume
=> Vec
::new(),
536 Return
=> Vec
::new(),
537 Unreachable
=> Vec
::new(),
538 Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut c), .. }
=> vec
![t
, c
],
539 Call { destination: Some((_, ref mut t)), cleanup: None, .. }
=> vec
![t
],
540 Call { destination: None, cleanup: Some(ref mut c), .. }
=> vec
![c
],
541 Call { destination: None, cleanup: None, .. }
=> vec
![],
542 DropAndReplace { ref mut target, unwind: Some(ref mut unwind), .. }
|
543 Drop { ref mut target, unwind: Some(ref mut unwind), .. }
=> vec
![target
, unwind
],
544 DropAndReplace { ref mut target, unwind: None, .. }
|
545 Drop { ref mut target, unwind: None, .. }
=> {
548 Assert { ref mut target, cleanup: Some(ref mut unwind), .. }
=> vec
![target
, unwind
],
549 Assert { ref mut target, .. }
=> vec
![target
]
554 impl<'tcx
> BasicBlockData
<'tcx
> {
555 pub fn new(terminator
: Option
<Terminator
<'tcx
>>) -> BasicBlockData
<'tcx
> {
558 terminator
: terminator
,
563 /// Accessor for terminator.
565 /// Terminator may not be None after construction of the basic block is complete. This accessor
566 /// provides a convenience way to reach the terminator.
567 pub fn terminator(&self) -> &Terminator
<'tcx
> {
568 self.terminator
.as_ref().expect("invalid terminator state")
571 pub fn terminator_mut(&mut self) -> &mut Terminator
<'tcx
> {
572 self.terminator
.as_mut().expect("invalid terminator state")
576 impl<'tcx
> Debug
for TerminatorKind
<'tcx
> {
577 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
579 let successors
= self.successors();
580 let labels
= self.fmt_successor_labels();
581 assert_eq
!(successors
.len(), labels
.len());
583 match successors
.len() {
586 1 => write
!(fmt
, " -> {:?}", successors
[0]),
589 write
!(fmt
, " -> [")?
;
590 for (i
, target
) in successors
.iter().enumerate() {
594 write
!(fmt
, "{}: {:?}", labels
[i
], target
)?
;
603 impl<'tcx
> TerminatorKind
<'tcx
> {
604 /// Write the "head" part of the terminator; that is, its name and the data it uses to pick the
605 /// successor basic block, if any. The only information not inlcuded is the list of possible
606 /// successors, which may be rendered differently between the text and the graphviz format.
607 pub fn fmt_head
<W
: Write
>(&self, fmt
: &mut W
) -> fmt
::Result
{
608 use self::TerminatorKind
::*;
610 Goto { .. }
=> write
!(fmt
, "goto"),
611 If { cond: ref lv, .. }
=> write
!(fmt
, "if({:?})", lv
),
612 Switch { discr: ref lv, .. }
=> write
!(fmt
, "switch({:?})", lv
),
613 SwitchInt { discr: ref lv, .. }
=> write
!(fmt
, "switchInt({:?})", lv
),
614 Return
=> write
!(fmt
, "return"),
615 Resume
=> write
!(fmt
, "resume"),
616 Unreachable
=> write
!(fmt
, "unreachable"),
617 Drop { ref location, .. }
=> write
!(fmt
, "drop({:?})", location
),
618 DropAndReplace { ref location, ref value, .. }
=>
619 write
!(fmt
, "replace({:?} <- {:?})", location
, value
),
620 Call { ref func, ref args, ref destination, .. }
=> {
621 if let Some((ref destination
, _
)) = *destination
{
622 write
!(fmt
, "{:?} = ", destination
)?
;
624 write
!(fmt
, "{:?}(", func
)?
;
625 for (index
, arg
) in args
.iter().enumerate() {
629 write
!(fmt
, "{:?}", arg
)?
;
633 Assert { ref cond, expected, ref msg, .. }
=> {
634 write
!(fmt
, "assert(")?
;
638 write
!(fmt
, "{:?}, ", cond
)?
;
641 AssertMessage
::BoundsCheck { ref len, ref index }
=> {
642 write
!(fmt
, "{:?}, {:?}, {:?}",
643 "index out of bounds: the len is {} but the index is {}",
646 AssertMessage
::Math(ref err
) => {
647 write
!(fmt
, "{:?}", err
.description())?
;
656 /// Return the list of labels for the edges to the successor basic blocks.
657 pub fn fmt_successor_labels(&self) -> Vec
<Cow
<'
static, str>> {
658 use self::TerminatorKind
::*;
660 Return
| Resume
| Unreachable
=> vec
![],
661 Goto { .. }
=> vec
!["".into()],
662 If { .. }
=> vec
!["true".into(), "false".into()],
663 Switch { ref adt_def, .. }
=> {
666 .map(|variant
| variant
.name
.to_string().into())
669 SwitchInt { ref values, .. }
=> {
672 let mut buf
= String
::new();
673 fmt_const_val(&mut buf
, const_val
).unwrap();
676 .chain(iter
::once(String
::from("otherwise").into()))
679 Call { destination: Some(_), cleanup: Some(_), .. }
=>
680 vec
!["return".into_cow(), "unwind".into_cow()],
681 Call { destination: Some(_), cleanup: None, .. }
=> vec
!["return".into_cow()],
682 Call { destination: None, cleanup: Some(_), .. }
=> vec
!["unwind".into_cow()],
683 Call { destination: None, cleanup: None, .. }
=> vec
![],
684 DropAndReplace { unwind: None, .. }
|
685 Drop { unwind: None, .. }
=> vec
!["return".into_cow()],
686 DropAndReplace { unwind: Some(_), .. }
|
687 Drop { unwind: Some(_), .. }
=> {
688 vec
!["return".into_cow(), "unwind".into_cow()]
690 Assert { cleanup: None, .. }
=> vec
!["".into()],
692 vec
!["success".into_cow(), "unwind".into_cow()]
697 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
698 pub enum AssertMessage
<'tcx
> {
706 ///////////////////////////////////////////////////////////////////////////
709 #[derive(Clone, RustcEncodable, RustcDecodable)]
710 pub struct Statement
<'tcx
> {
711 pub source_info
: SourceInfo
,
712 pub kind
: StatementKind
<'tcx
>,
715 impl<'tcx
> Statement
<'tcx
> {
716 /// Changes a statement to a nop. This is both faster than deleting instructions and avoids
717 /// invalidating statement indices in `Location`s.
718 pub fn make_nop(&mut self) {
719 self.kind
= StatementKind
::Nop
723 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
724 pub enum StatementKind
<'tcx
> {
725 /// Write the RHS Rvalue to the LHS Lvalue.
726 Assign(Lvalue
<'tcx
>, Rvalue
<'tcx
>),
728 /// Write the discriminant for a variant to the enum Lvalue.
729 SetDiscriminant { lvalue: Lvalue<'tcx>, variant_index: usize }
,
731 /// Start a live range for the storage of the local.
732 StorageLive(Lvalue
<'tcx
>),
734 /// End the current live range for the storage of the local.
735 StorageDead(Lvalue
<'tcx
>),
737 /// No-op. Useful for deleting instructions without affecting statement indices.
741 impl<'tcx
> Debug
for Statement
<'tcx
> {
742 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
743 use self::StatementKind
::*;
745 Assign(ref lv
, ref rv
) => write
!(fmt
, "{:?} = {:?}", lv
, rv
),
746 StorageLive(ref lv
) => write
!(fmt
, "StorageLive({:?})", lv
),
747 StorageDead(ref lv
) => write
!(fmt
, "StorageDead({:?})", lv
),
748 SetDiscriminant{lvalue: ref lv, variant_index: index}
=> {
749 write
!(fmt
, "discriminant({:?}) = {:?}", lv
, index
)
751 Nop
=> write
!(fmt
, "nop"),
756 ///////////////////////////////////////////////////////////////////////////
759 newtype_index
!(Var
, "var");
760 newtype_index
!(Temp
, "tmp");
761 newtype_index
!(Arg
, "arg");
762 newtype_index
!(Local
, "local");
764 /// A path to a value; something that can be evaluated without
765 /// changing or disturbing program state.
766 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
767 pub enum Lvalue
<'tcx
> {
768 /// local variable declared by the user
771 /// temporary introduced during lowering into MIR
774 /// formal parameter of the function; note that these are NOT the
775 /// bindings that the user declares, which are vars
778 /// static or static mut variable
781 /// the return pointer of the fn
784 /// projection out of an lvalue (access a field, deref a pointer, etc)
785 Projection(Box
<LvalueProjection
<'tcx
>>),
788 /// The `Projection` data structure defines things of the form `B.x`
789 /// or `*B` or `B[index]`. Note that it is parameterized because it is
790 /// shared between `Constant` and `Lvalue`. See the aliases
791 /// `LvalueProjection` etc below.
792 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
793 pub struct Projection
<'tcx
, B
, V
> {
795 pub elem
: ProjectionElem
<'tcx
, V
>,
798 #[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
799 pub enum ProjectionElem
<'tcx
, V
> {
801 Field(Field
, Ty
<'tcx
>),
804 /// These indices are generated by slice patterns. Easiest to explain
808 /// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
809 /// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
810 /// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
811 /// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
814 /// index or -index (in Python terms), depending on from_end
816 /// thing being indexed must be at least this long
818 /// counting backwards from end?
822 /// These indices are generated by slice patterns.
824 /// slice[from:-to] in Python terms.
830 /// "Downcast" to a variant of an ADT. Currently, we only introduce
831 /// this for ADTs with more than one variant. It may be better to
832 /// just introduce it always, or always for enums.
833 Downcast(AdtDef
<'tcx
>, usize),
836 /// Alias for projections as they appear in lvalues, where the base is an lvalue
837 /// and the index is an operand.
838 pub type LvalueProjection
<'tcx
> = Projection
<'tcx
, Lvalue
<'tcx
>, Operand
<'tcx
>>;
840 /// Alias for projections as they appear in lvalues, where the base is an lvalue
841 /// and the index is an operand.
842 pub type LvalueElem
<'tcx
> = ProjectionElem
<'tcx
, Operand
<'tcx
>>;
844 newtype_index
!(Field
, "field");
846 impl<'tcx
> Lvalue
<'tcx
> {
847 pub fn field(self, f
: Field
, ty
: Ty
<'tcx
>) -> Lvalue
<'tcx
> {
848 self.elem(ProjectionElem
::Field(f
, ty
))
851 pub fn deref(self) -> Lvalue
<'tcx
> {
852 self.elem(ProjectionElem
::Deref
)
855 pub fn index(self, index
: Operand
<'tcx
>) -> Lvalue
<'tcx
> {
856 self.elem(ProjectionElem
::Index(index
))
859 pub fn elem(self, elem
: LvalueElem
<'tcx
>) -> Lvalue
<'tcx
> {
860 Lvalue
::Projection(Box
::new(LvalueProjection
{
866 pub fn from_local(mir
: &Mir
<'tcx
>, local
: Local
) -> Lvalue
<'tcx
> {
867 let mut index
= local
.index();
868 index
= match index
.checked_sub(mir
.arg_decls
.len()) {
869 None
=> return Lvalue
::Arg(Arg(index
as u32)),
870 Some(index
) => index
,
872 index
= match index
.checked_sub(mir
.var_decls
.len()) {
873 None
=> return Lvalue
::Var(Var(index
as u32)),
874 Some(index
) => index
,
876 index
= match index
.checked_sub(mir
.temp_decls
.len()) {
877 None
=> return Lvalue
::Temp(Temp(index
as u32)),
878 Some(index
) => index
,
880 debug_assert
!(index
== 0);
881 Lvalue
::ReturnPointer
885 impl<'tcx
> Debug
for Lvalue
<'tcx
> {
886 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
890 Var(id
) => write
!(fmt
, "{:?}", id
),
891 Arg(id
) => write
!(fmt
, "{:?}", id
),
892 Temp(id
) => write
!(fmt
, "{:?}", id
),
894 write
!(fmt
, "{}", ty
::tls
::with(|tcx
| tcx
.item_path_str(def_id
))),
896 write
!(fmt
, "return"),
897 Projection(ref data
) =>
899 ProjectionElem
::Downcast(ref adt_def
, index
) =>
900 write
!(fmt
, "({:?} as {})", data
.base
, adt_def
.variants
[index
].name
),
901 ProjectionElem
::Deref
=>
902 write
!(fmt
, "(*{:?})", data
.base
),
903 ProjectionElem
::Field(field
, ty
) =>
904 write
!(fmt
, "({:?}.{:?}: {:?})", data
.base
, field
.index(), ty
),
905 ProjectionElem
::Index(ref index
) =>
906 write
!(fmt
, "{:?}[{:?}]", data
.base
, index
),
907 ProjectionElem
::ConstantIndex { offset, min_length, from_end: false }
=>
908 write
!(fmt
, "{:?}[{:?} of {:?}]", data
.base
, offset
, min_length
),
909 ProjectionElem
::ConstantIndex { offset, min_length, from_end: true }
=>
910 write
!(fmt
, "{:?}[-{:?} of {:?}]", data
.base
, offset
, min_length
),
911 ProjectionElem
::Subslice { from, to }
if to
== 0 =>
912 write
!(fmt
, "{:?}[{:?}:", data
.base
, from
),
913 ProjectionElem
::Subslice { from, to }
if from
== 0 =>
914 write
!(fmt
, "{:?}[:-{:?}]", data
.base
, to
),
915 ProjectionElem
::Subslice { from, to }
=>
916 write
!(fmt
, "{:?}[{:?}:-{:?}]", data
.base
,
924 ///////////////////////////////////////////////////////////////////////////
927 newtype_index
!(VisibilityScope
, "scope");
928 pub const ARGUMENT_VISIBILITY_SCOPE
: VisibilityScope
= VisibilityScope(0);
930 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
931 pub struct VisibilityScopeData
{
933 pub parent_scope
: Option
<VisibilityScope
>,
936 ///////////////////////////////////////////////////////////////////////////
939 /// These are values that can appear inside an rvalue (or an index
940 /// lvalue). They are intentionally limited to prevent rvalues from
941 /// being nested in one another.
942 #[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
943 pub enum Operand
<'tcx
> {
944 Consume(Lvalue
<'tcx
>),
945 Constant(Constant
<'tcx
>),
948 impl<'tcx
> Debug
for Operand
<'tcx
> {
949 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
950 use self::Operand
::*;
952 Constant(ref a
) => write
!(fmt
, "{:?}", a
),
953 Consume(ref lv
) => write
!(fmt
, "{:?}", lv
),
958 ///////////////////////////////////////////////////////////////////////////
961 #[derive(Clone, RustcEncodable, RustcDecodable)]
962 pub enum Rvalue
<'tcx
> {
963 /// x (either a move or copy, depending on type of x)
967 Repeat(Operand
<'tcx
>, TypedConstVal
<'tcx
>),
970 Ref(&'tcx Region
, BorrowKind
, Lvalue
<'tcx
>),
972 /// length of a [X] or [X;n] value
975 Cast(CastKind
, Operand
<'tcx
>, Ty
<'tcx
>),
977 BinaryOp(BinOp
, Operand
<'tcx
>, Operand
<'tcx
>),
978 CheckedBinaryOp(BinOp
, Operand
<'tcx
>, Operand
<'tcx
>),
980 UnaryOp(UnOp
, Operand
<'tcx
>),
982 /// Creates an *uninitialized* Box
985 /// Create an aggregate value, like a tuple or struct. This is
986 /// only needed because we want to distinguish `dest = Foo { x:
987 /// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
988 /// that `Foo` has a destructor. These rvalues can be optimized
989 /// away after type-checking and before lowering.
990 Aggregate(AggregateKind
<'tcx
>, Vec
<Operand
<'tcx
>>),
994 outputs
: Vec
<Lvalue
<'tcx
>>,
995 inputs
: Vec
<Operand
<'tcx
>>
999 #[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1003 /// Convert unique, zero-sized type for a fn to fn()
1006 /// Convert safe fn() to unsafe fn()
1009 /// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
1010 /// trans must figure out the details once full monomorphization
1011 /// is known. For example, this could be used to cast from a
1012 /// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<Trait>`
1013 /// (presuming `T: Trait`).
1017 #[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1018 pub enum AggregateKind
<'tcx
> {
1021 /// The second field is variant number (discriminant), it's equal to 0
1022 /// for struct and union expressions. The fourth field is active field
1023 /// number and is present only for union expressions.
1024 Adt(AdtDef
<'tcx
>, usize, &'tcx Substs
<'tcx
>, Option
<usize>),
1025 Closure(DefId
, ClosureSubsts
<'tcx
>),
1028 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1030 /// The `+` operator (addition)
1032 /// The `-` operator (subtraction)
1034 /// The `*` operator (multiplication)
1036 /// The `/` operator (division)
1038 /// The `%` operator (modulus)
1040 /// The `^` operator (bitwise xor)
1042 /// The `&` operator (bitwise and)
1044 /// The `|` operator (bitwise or)
1046 /// The `<<` operator (shift left)
1048 /// The `>>` operator (shift right)
1050 /// The `==` operator (equality)
1052 /// The `<` operator (less than)
1054 /// The `<=` operator (less than or equal to)
1056 /// The `!=` operator (not equal to)
1058 /// The `>=` operator (greater than or equal to)
1060 /// The `>` operator (greater than)
1065 pub fn is_checkable(self) -> bool
{
1068 Add
| Sub
| Mul
| Shl
| Shr
=> true,
1074 #[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
1076 /// The `!` operator for logical inversion
1078 /// The `-` operator for negation
1082 impl<'tcx
> Debug
for Rvalue
<'tcx
> {
1083 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1084 use self::Rvalue
::*;
1087 Use(ref lvalue
) => write
!(fmt
, "{:?}", lvalue
),
1088 Repeat(ref a
, ref b
) => write
!(fmt
, "[{:?}; {:?}]", a
, b
),
1089 Len(ref a
) => write
!(fmt
, "Len({:?})", a
),
1090 Cast(ref kind
, ref lv
, ref ty
) => write
!(fmt
, "{:?} as {:?} ({:?})", lv
, ty
, kind
),
1091 BinaryOp(ref op
, ref a
, ref b
) => write
!(fmt
, "{:?}({:?}, {:?})", op
, a
, b
),
1092 CheckedBinaryOp(ref op
, ref a
, ref b
) => {
1093 write
!(fmt
, "Checked{:?}({:?}, {:?})", op
, a
, b
)
1095 UnaryOp(ref op
, ref a
) => write
!(fmt
, "{:?}({:?})", op
, a
),
1096 Box(ref t
) => write
!(fmt
, "Box({:?})", t
),
1097 InlineAsm { ref asm, ref outputs, ref inputs }
=> {
1098 write
!(fmt
, "asm!({:?} : {:?} : {:?})", asm
, outputs
, inputs
)
1101 Ref(_
, borrow_kind
, ref lv
) => {
1102 let kind_str
= match borrow_kind
{
1103 BorrowKind
::Shared
=> "",
1104 BorrowKind
::Mut
| BorrowKind
::Unique
=> "mut ",
1106 write
!(fmt
, "&{}{:?}", kind_str
, lv
)
1109 Aggregate(ref kind
, ref lvs
) => {
1110 use self::AggregateKind
::*;
1112 fn fmt_tuple(fmt
: &mut Formatter
, lvs
: &[Operand
]) -> fmt
::Result
{
1113 let mut tuple_fmt
= fmt
.debug_tuple("");
1115 tuple_fmt
.field(lv
);
1121 Vec
=> write
!(fmt
, "{:?}", lvs
),
1125 0 => write
!(fmt
, "()"),
1126 1 => write
!(fmt
, "({:?},)", lvs
[0]),
1127 _
=> fmt_tuple(fmt
, lvs
),
1131 Adt(adt_def
, variant
, substs
, _
) => {
1132 let variant_def
= &adt_def
.variants
[variant
];
1134 ppaux
::parameterized(fmt
, substs
, variant_def
.did
, &[])?
;
1136 match variant_def
.kind
{
1137 ty
::VariantKind
::Unit
=> Ok(()),
1138 ty
::VariantKind
::Tuple
=> fmt_tuple(fmt
, lvs
),
1139 ty
::VariantKind
::Struct
=> {
1140 let mut struct_fmt
= fmt
.debug_struct("");
1141 for (field
, lv
) in variant_def
.fields
.iter().zip(lvs
) {
1142 struct_fmt
.field(&field
.name
.as_str(), lv
);
1149 Closure(def_id
, _
) => ty
::tls
::with(|tcx
| {
1150 if let Some(node_id
) = tcx
.map
.as_local_node_id(def_id
) {
1151 let name
= format
!("[closure@{:?}]", tcx
.map
.span(node_id
));
1152 let mut struct_fmt
= fmt
.debug_struct(&name
);
1154 tcx
.with_freevars(node_id
, |freevars
| {
1155 for (freevar
, lv
) in freevars
.iter().zip(lvs
) {
1156 let def_id
= freevar
.def
.def_id();
1157 let var_id
= tcx
.map
.as_local_node_id(def_id
).unwrap();
1158 let var_name
= tcx
.local_var_name_str(var_id
);
1159 struct_fmt
.field(&var_name
, lv
);
1165 write
!(fmt
, "[closure]")
1174 ///////////////////////////////////////////////////////////////////////////
1177 /// Two constants are equal if they are the same constant. Note that
1178 /// this does not necessarily mean that they are "==" in Rust -- in
1179 /// particular one must be wary of `NaN`!
1181 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1182 pub struct Constant
<'tcx
> {
1185 pub literal
: Literal
<'tcx
>,
1188 #[derive(Clone, RustcEncodable, RustcDecodable)]
1189 pub struct TypedConstVal
<'tcx
> {
1192 pub value
: ConstUsize
,
1195 impl<'tcx
> Debug
for TypedConstVal
<'tcx
> {
1196 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1197 write
!(fmt
, "const {}", ConstInt
::Usize(self.value
))
1201 newtype_index
!(Promoted
, "promoted");
1203 #[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
1204 pub enum Literal
<'tcx
> {
1207 substs
: &'tcx Substs
<'tcx
>,
1213 // Index into the `promoted` vector of `Mir`.
1218 impl<'tcx
> Debug
for Constant
<'tcx
> {
1219 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1220 write
!(fmt
, "{:?}", self.literal
)
1224 impl<'tcx
> Debug
for Literal
<'tcx
> {
1225 fn fmt(&self, fmt
: &mut Formatter
) -> fmt
::Result
{
1226 use self::Literal
::*;
1228 Item { def_id, substs }
=> {
1229 ppaux
::parameterized(fmt
, substs
, def_id
, &[])
1231 Value { ref value }
=> {
1232 write
!(fmt
, "const ")?
;
1233 fmt_const_val(fmt
, value
)
1235 Promoted { index }
=> {
1236 write
!(fmt
, "{:?}", index
)
1242 /// Write a `ConstVal` in a way closer to the original source code than the `Debug` output.
1243 fn fmt_const_val
<W
: Write
>(fmt
: &mut W
, const_val
: &ConstVal
) -> fmt
::Result
{
1244 use middle
::const_val
::ConstVal
::*;
1246 Float(f
) => write
!(fmt
, "{:?}", f
),
1247 Integral(n
) => write
!(fmt
, "{}", n
),
1248 Str(ref s
) => write
!(fmt
, "{:?}", s
),
1249 ByteStr(ref bytes
) => {
1250 let escaped
: String
= bytes
1252 .flat_map(|&ch
| ascii
::escape_default(ch
).map(|c
| c
as char))
1254 write
!(fmt
, "b\"{}\"", escaped
)
1256 Bool(b
) => write
!(fmt
, "{:?}", b
),
1257 Function(def_id
) => write
!(fmt
, "{}", item_path_str(def_id
)),
1258 Struct(node_id
) | Tuple(node_id
) | Array(node_id
, _
) | Repeat(node_id
, _
) =>
1259 write
!(fmt
, "{}", node_to_string(node_id
)),
1260 Char(c
) => write
!(fmt
, "{:?}", c
),
1265 fn node_to_string(node_id
: ast
::NodeId
) -> String
{
1266 ty
::tls
::with(|tcx
| tcx
.map
.node_to_user_string(node_id
))
1269 fn item_path_str(def_id
: DefId
) -> String
{
1270 ty
::tls
::with(|tcx
| tcx
.item_path_str(def_id
))
1273 impl<'tcx
> ControlFlowGraph
for Mir
<'tcx
> {
1275 type Node
= BasicBlock
;
1277 fn num_nodes(&self) -> usize { self.basic_blocks.len() }
1279 fn start_node(&self) -> Self::Node { START_BLOCK }
1281 fn predecessors
<'graph
>(&'graph
self, node
: Self::Node
)
1282 -> <Self as GraphPredecessors
<'graph
>>::Iter
1284 self.predecessors_for(node
).clone().into_iter()
1286 fn successors
<'graph
>(&'graph
self, node
: Self::Node
)
1287 -> <Self as GraphSuccessors
<'graph
>>::Iter
1289 self.basic_blocks
[node
].terminator().successors().into_owned().into_iter()
1293 impl<'a
, 'b
> GraphPredecessors
<'b
> for Mir
<'a
> {
1294 type Item
= BasicBlock
;
1295 type Iter
= IntoIter
<BasicBlock
>;
1298 impl<'a
, 'b
> GraphSuccessors
<'b
> for Mir
<'a
> {
1299 type Item
= BasicBlock
;
1300 type Iter
= IntoIter
<BasicBlock
>;
1303 #[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
1304 pub struct Location
{
1305 /// the location is within this block
1306 pub block
: BasicBlock
,
1308 /// the location is the start of the this statement; or, if `statement_index`
1309 /// == num-statements, then the start of the terminator.
1310 pub statement_index
: usize,
1313 impl fmt
::Debug
for Location
{
1314 fn fmt(&self, fmt
: &mut fmt
::Formatter
) -> fmt
::Result
{
1315 write
!(fmt
, "{:?}[{}]", self.block
, self.statement_index
)
1320 pub fn dominates(&self, other
: &Location
, dominators
: &Dominators
<BasicBlock
>) -> bool
{
1321 if self.block
== other
.block
{
1322 self.statement_index
<= other
.statement_index
1324 dominators
.is_dominated_by(other
.block
, self.block
)