5 use rustc_data_structures
::stable_hasher
::{HashStable, StableHasher}
;
6 use rustc_hir
::{self as hir, def_id::DefId, definitions::DefPathData}
;
7 use rustc_index
::vec
::IndexVec
;
8 use rustc_macros
::HashStable
;
9 use rustc_middle
::ich
::StableHashingContext
;
10 use rustc_middle
::mir
;
11 use rustc_middle
::ty
::layout
::{self, TyAndLayout}
;
12 use rustc_middle
::ty
::{
13 self, query
::TyCtxtAt
, subst
::SubstsRef
, ParamEnv
, Ty
, TyCtxt
, TypeFoldable
,
15 use rustc_session
::Limit
;
16 use rustc_span
::{Pos, Span}
;
17 use rustc_target
::abi
::{Align, HasDataLayout, LayoutOf, Size, TargetDataLayout}
;
20 AllocId
, GlobalId
, Immediate
, InterpResult
, MPlaceTy
, Machine
, MemPlace
, MemPlaceMeta
, Memory
,
21 MemoryKind
, Operand
, Place
, PlaceTy
, Pointer
, Provenance
, Scalar
, ScalarMaybeUninit
,
24 use crate::transform
::validate
::equal_up_to_regions
;
25 use crate::util
::storage
::AlwaysLiveLocals
;
27 pub struct InterpCx
<'mir
, 'tcx
, M
: Machine
<'mir
, 'tcx
>> {
28 /// Stores the `Machine` instance.
30 /// Note: the stack is provided by the machine.
33 /// The results of the type checker, from rustc.
34 /// The span in this is the "root" of the evaluation, i.e., the const
35 /// we are evaluating (if this is CTFE).
36 pub tcx
: TyCtxtAt
<'tcx
>,
38 /// Bounds in scope for polymorphic evaluations.
39 pub(crate) param_env
: ty
::ParamEnv
<'tcx
>,
41 /// The virtual memory system.
42 pub memory
: Memory
<'mir
, 'tcx
, M
>,
44 /// The recursion limit (cached from `tcx.recursion_limit(())`)
45 pub recursion_limit
: Limit
,
48 // The Phantomdata exists to prevent this type from being `Send`. If it were sent across a thread
49 // boundary and dropped in the other thread, it would exit the span in the other thread.
50 struct SpanGuard(tracing
::Span
, std
::marker
::PhantomData
<*const u8>);
53 /// By default a `SpanGuard` does nothing.
55 Self(tracing
::Span
::none(), std
::marker
::PhantomData
)
58 /// If a span is entered, we exit the previous span (if any, normally none) and enter the
59 /// new span. This is mainly so we don't have to use `Option` for the `tracing_span` field of
60 /// `Frame` by creating a dummy span to being with and then entering it once the frame has
62 fn enter(&mut self, span
: tracing
::Span
) {
63 // This executes the destructor on the previous instance of `SpanGuard`, ensuring that
64 // we never enter or exit more spans than vice versa. Unless you `mem::leak`, then we
65 // can't protect the tracing stack, but that'll just lead to weird logging, no actual
67 *self = Self(span
, std
::marker
::PhantomData
);
68 self.0.with_subscriber(|(id
, dispatch
)| {
74 impl Drop
for SpanGuard
{
76 self.0.with_subscriber(|(id
, dispatch
)| {
83 pub struct Frame
<'mir
, 'tcx
, Tag
: Provenance
= AllocId
, Extra
= ()> {
84 ////////////////////////////////////////////////////////////////////////////////
85 // Function and callsite information
86 ////////////////////////////////////////////////////////////////////////////////
87 /// The MIR for the function called on this frame.
88 pub body
: &'mir mir
::Body
<'tcx
>,
90 /// The def_id and substs of the current function.
91 pub instance
: ty
::Instance
<'tcx
>,
93 /// Extra data for the machine.
96 ////////////////////////////////////////////////////////////////////////////////
97 // Return place and locals
98 ////////////////////////////////////////////////////////////////////////////////
99 /// Work to perform when returning from this function.
100 pub return_to_block
: StackPopCleanup
,
102 /// The location where the result of the current stack frame should be written to,
103 /// and its layout in the caller.
104 pub return_place
: Option
<PlaceTy
<'tcx
, Tag
>>,
106 /// The list of locals for this stack frame, stored in order as
107 /// `[return_ptr, arguments..., variables..., temporaries...]`.
108 /// The locals are stored as `Option<Value>`s.
109 /// `None` represents a local that is currently dead, while a live local
110 /// can either directly contain `Scalar` or refer to some part of an `Allocation`.
111 pub locals
: IndexVec
<mir
::Local
, LocalState
<'tcx
, Tag
>>,
113 /// The span of the `tracing` crate is stored here.
114 /// When the guard is dropped, the span is exited. This gives us
115 /// a full stack trace on all tracing statements.
116 tracing_span
: SpanGuard
,
118 ////////////////////////////////////////////////////////////////////////////////
119 // Current position within the function
120 ////////////////////////////////////////////////////////////////////////////////
121 /// If this is `Err`, we are not currently executing any particular statement in
122 /// this frame (can happen e.g. during frame initialization, and during unwinding on
123 /// frames without cleanup code).
124 /// We basically abuse `Result` as `Either`.
125 pub(super) loc
: Result
<mir
::Location
, Span
>,
128 /// What we store about a frame in an interpreter backtrace.
130 pub struct FrameInfo
<'tcx
> {
131 pub instance
: ty
::Instance
<'tcx
>,
133 pub lint_root
: Option
<hir
::HirId
>,
136 /// Unwind information.
137 #[derive(Clone, Copy, Eq, PartialEq, Debug, HashStable)]
138 pub enum StackPopUnwind
{
139 /// The cleanup block.
140 Cleanup(mir
::BasicBlock
),
141 /// No cleanup needs to be done.
143 /// Unwinding is not allowed (UB).
147 #[derive(Clone, Copy, Eq, PartialEq, Debug, HashStable)] // Miri debug-prints these
148 pub enum StackPopCleanup
{
149 /// Jump to the next block in the caller, or cause UB if None (that's a function
150 /// that may never return). Also store layout of return place so
151 /// we can validate it at that layout.
152 /// `ret` stores the block we jump to on a normal return, while `unwind`
153 /// stores the block used for cleanup during unwinding.
154 Goto { ret: Option<mir::BasicBlock>, unwind: StackPopUnwind }
,
155 /// Just do nothing: Used by Main and for the `box_alloc` hook in miri.
156 /// `cleanup` says whether locals are deallocated. Static computation
157 /// wants them leaked to intern what they need (and just throw away
158 /// the entire `ecx` when it is done).
159 None { cleanup: bool }
,
162 /// State of a local variable including a memoized layout
163 #[derive(Clone, PartialEq, Eq, HashStable)]
164 pub struct LocalState
<'tcx
, Tag
: Provenance
= AllocId
> {
165 pub value
: LocalValue
<Tag
>,
166 /// Don't modify if `Some`, this is only used to prevent computing the layout twice
167 #[stable_hasher(ignore)]
168 pub layout
: Cell
<Option
<TyAndLayout
<'tcx
>>>,
171 /// Current value of a local variable
172 #[derive(Copy, Clone, PartialEq, Eq, HashStable, Debug)] // Miri debug-prints these
173 pub enum LocalValue
<Tag
: Provenance
= AllocId
> {
174 /// This local is not currently alive, and cannot be used at all.
176 /// This local is alive but not yet initialized. It can be written to
177 /// but not read from or its address taken. Locals get initialized on
178 /// first write because for unsized locals, we do not know their size
181 /// A normal, live local.
182 /// Mostly for convenience, we re-use the `Operand` type here.
183 /// This is an optimization over just always having a pointer here;
184 /// we can thus avoid doing an allocation when the local just stores
185 /// immediate values *and* never has its address taken.
189 impl<'tcx
, Tag
: Provenance
+ '
static> LocalState
<'tcx
, Tag
> {
190 /// Read the local's value or error if the local is not yet live or not live anymore.
192 /// Note: This may only be invoked from the `Machine::access_local` hook and not from
193 /// anywhere else. You may be invalidating machine invariants if you do!
194 pub fn access(&self) -> InterpResult
<'tcx
, Operand
<Tag
>> {
196 LocalValue
::Dead
=> throw_ub
!(DeadLocal
),
197 LocalValue
::Uninitialized
=> {
198 bug
!("The type checker should prevent reading from a never-written local")
200 LocalValue
::Live(val
) => Ok(val
),
204 /// Overwrite the local. If the local can be overwritten in place, return a reference
205 /// to do so; otherwise return the `MemPlace` to consult instead.
207 /// Note: This may only be invoked from the `Machine::access_local_mut` hook and not from
208 /// anywhere else. You may be invalidating machine invariants if you do!
211 ) -> InterpResult
<'tcx
, Result
<&mut LocalValue
<Tag
>, MemPlace
<Tag
>>> {
213 LocalValue
::Dead
=> throw_ub
!(DeadLocal
),
214 LocalValue
::Live(Operand
::Indirect(mplace
)) => Ok(Err(mplace
)),
216 local @
(LocalValue
::Live(Operand
::Immediate(_
)) | LocalValue
::Uninitialized
) => {
223 impl<'mir
, 'tcx
, Tag
: Provenance
> Frame
<'mir
, 'tcx
, Tag
> {
224 pub fn with_extra
<Extra
>(self, extra
: Extra
) -> Frame
<'mir
, 'tcx
, Tag
, Extra
> {
227 instance
: self.instance
,
228 return_to_block
: self.return_to_block
,
229 return_place
: self.return_place
,
233 tracing_span
: self.tracing_span
,
238 impl<'mir
, 'tcx
, Tag
: Provenance
, Extra
> Frame
<'mir
, 'tcx
, Tag
, Extra
> {
239 /// Get the current location within the Frame.
241 /// If this is `Err`, we are not currently executing any particular statement in
242 /// this frame (can happen e.g. during frame initialization, and during unwinding on
243 /// frames without cleanup code).
244 /// We basically abuse `Result` as `Either`.
247 pub fn current_loc(&self) -> Result
<mir
::Location
, Span
> {
251 /// Return the `SourceInfo` of the current instruction.
252 pub fn current_source_info(&self) -> Option
<&mir
::SourceInfo
> {
253 self.loc
.ok().map(|loc
| self.body
.source_info(loc
))
256 pub fn current_span(&self) -> Span
{
258 Ok(loc
) => self.body
.source_info(loc
).span
,
264 impl<'tcx
> fmt
::Display
for FrameInfo
<'tcx
> {
265 fn fmt(&self, f
: &mut fmt
::Formatter
<'_
>) -> fmt
::Result
{
266 ty
::tls
::with(|tcx
| {
267 if tcx
.def_key(self.instance
.def_id()).disambiguated_data
.data
268 == DefPathData
::ClosureExpr
270 write
!(f
, "inside closure")?
;
272 write
!(f
, "inside `{}`", self.instance
)?
;
274 if !self.span
.is_dummy() {
275 let sm
= tcx
.sess
.source_map();
276 let lo
= sm
.lookup_char_pos(self.span
.lo());
280 sm
.filename_for_diagnostics(&lo
.file
.name
),
282 lo
.col
.to_usize() + 1
290 impl<'mir
, 'tcx
, M
: Machine
<'mir
, 'tcx
>> HasDataLayout
for InterpCx
<'mir
, 'tcx
, M
> {
292 fn data_layout(&self) -> &TargetDataLayout
{
293 &self.tcx
.data_layout
297 impl<'mir
, 'tcx
, M
> layout
::HasTyCtxt
<'tcx
> for InterpCx
<'mir
, 'tcx
, M
>
299 M
: Machine
<'mir
, 'tcx
>,
302 fn tcx(&self) -> TyCtxt
<'tcx
> {
307 impl<'mir
, 'tcx
, M
> layout
::HasParamEnv
<'tcx
> for InterpCx
<'mir
, 'tcx
, M
>
309 M
: Machine
<'mir
, 'tcx
>,
311 fn param_env(&self) -> ty
::ParamEnv
<'tcx
> {
316 impl<'mir
, 'tcx
: 'mir
, M
: Machine
<'mir
, 'tcx
>> LayoutOf
<'tcx
> for InterpCx
<'mir
, 'tcx
, M
> {
318 type TyAndLayout
= InterpResult
<'tcx
, TyAndLayout
<'tcx
>>;
321 fn layout_of(&self, ty
: Ty
<'tcx
>) -> Self::TyAndLayout
{
323 .layout_of(self.param_env
.and(ty
))
324 .map_err(|layout
| err_inval
!(Layout(layout
)).into())
328 /// Test if it is valid for a MIR assignment to assign `src`-typed place to `dest`-typed value.
329 /// This test should be symmetric, as it is primarily about layout compatibility.
330 pub(super) fn mir_assign_valid_types
<'tcx
>(
332 param_env
: ParamEnv
<'tcx
>,
333 src
: TyAndLayout
<'tcx
>,
334 dest
: TyAndLayout
<'tcx
>,
336 // Type-changing assignments can happen when subtyping is used. While
337 // all normal lifetimes are erased, higher-ranked types with their
338 // late-bound lifetimes are still around and can lead to type
339 // differences. So we compare ignoring lifetimes.
340 if equal_up_to_regions(tcx
, param_env
, src
.ty
, dest
.ty
) {
341 // Make sure the layout is equal, too -- just to be safe. Miri really
342 // needs layout equality. For performance reason we skip this check when
343 // the types are equal. Equal types *can* have different layouts when
344 // enum downcast is involved (as enum variants carry the type of the
345 // enum), but those should never occur in assignments.
346 if cfg
!(debug_assertions
) || src
.ty
!= dest
.ty
{
347 assert_eq
!(src
.layout
, dest
.layout
);
355 /// Use the already known layout if given (but sanity check in debug mode),
356 /// or compute the layout.
357 #[cfg_attr(not(debug_assertions), inline(always))]
358 pub(super) fn from_known_layout
<'tcx
>(
360 param_env
: ParamEnv
<'tcx
>,
361 known_layout
: Option
<TyAndLayout
<'tcx
>>,
362 compute
: impl FnOnce() -> InterpResult
<'tcx
, TyAndLayout
<'tcx
>>,
363 ) -> InterpResult
<'tcx
, TyAndLayout
<'tcx
>> {
366 Some(known_layout
) => {
367 if cfg
!(debug_assertions
) {
368 let check_layout
= compute()?
;
369 if !mir_assign_valid_types(tcx
.tcx
, param_env
, check_layout
, known_layout
) {
372 "expected type differs from actual type.\nexpected: {:?}\nactual: {:?}",
383 impl<'mir
, 'tcx
: 'mir
, M
: Machine
<'mir
, 'tcx
>> InterpCx
<'mir
, 'tcx
, M
> {
387 param_env
: ty
::ParamEnv
<'tcx
>,
389 memory_extra
: M
::MemoryExtra
,
393 tcx
: tcx
.at(root_span
),
395 memory
: Memory
::new(tcx
, memory_extra
),
396 recursion_limit
: tcx
.recursion_limit(),
401 pub fn cur_span(&self) -> Span
{
405 .find(|frame
| !frame
.instance
.def
.requires_caller_location(*self.tcx
))
406 .map_or(self.tcx
.span
, |f
| f
.current_span())
410 pub fn scalar_to_ptr(&self, scalar
: Scalar
<M
::PointerTag
>) -> Pointer
<Option
<M
::PointerTag
>> {
411 self.memory
.scalar_to_ptr(scalar
)
414 /// Call this to turn untagged "global" pointers (obtained via `tcx`) into
415 /// the machine pointer to the allocation. Must never be used
416 /// for any other pointers, nor for TLS statics.
418 /// Using the resulting pointer represents a *direct* access to that memory
419 /// (e.g. by directly using a `static`),
420 /// as opposed to access through a pointer that was created by the program.
422 /// This function can fail only if `ptr` points to an `extern static`.
424 pub fn global_base_pointer(&self, ptr
: Pointer
) -> InterpResult
<'tcx
, Pointer
<M
::PointerTag
>> {
425 self.memory
.global_base_pointer(ptr
)
429 pub(crate) fn stack(&self) -> &[Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
>] {
434 pub(crate) fn stack_mut(
436 ) -> &mut Vec
<Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
>> {
441 pub fn frame_idx(&self) -> usize {
442 let stack
= self.stack();
443 assert
!(!stack
.is_empty());
448 pub fn frame(&self) -> &Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
> {
449 self.stack().last().expect("no call frames exist")
453 pub fn frame_mut(&mut self) -> &mut Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
> {
454 self.stack_mut().last_mut().expect("no call frames exist")
458 pub(super) fn body(&self) -> &'mir mir
::Body
<'tcx
> {
463 pub fn sign_extend(&self, value
: u128
, ty
: TyAndLayout
<'_
>) -> u128
{
464 assert
!(ty
.abi
.is_signed());
465 ty
.size
.sign_extend(value
)
469 pub fn truncate(&self, value
: u128
, ty
: TyAndLayout
<'_
>) -> u128
{
470 ty
.size
.truncate(value
)
474 pub fn type_is_freeze(&self, ty
: Ty
<'tcx
>) -> bool
{
475 ty
.is_freeze(self.tcx
, self.param_env
)
480 instance
: ty
::InstanceDef
<'tcx
>,
481 promoted
: Option
<mir
::Promoted
>,
482 ) -> InterpResult
<'tcx
, &'tcx mir
::Body
<'tcx
>> {
483 // do not continue if typeck errors occurred (can only occur in local crate)
484 let def
= instance
.with_opt_param();
485 if let Some(def
) = def
.as_local() {
486 if self.tcx
.has_typeck_results(def
.did
) {
487 if let Some(error_reported
) = self.tcx
.typeck_opt_const_arg(def
).tainted_by_errors
{
488 throw_inval
!(AlreadyReported(error_reported
))
492 trace
!("load mir(instance={:?}, promoted={:?})", instance
, promoted
);
493 if let Some(promoted
) = promoted
{
494 return Ok(&self.tcx
.promoted_mir_opt_const_arg(def
)[promoted
]);
496 M
::load_mir(self, instance
)
499 /// Call this on things you got out of the MIR (so it is as generic as the current
500 /// stack frame), to bring it into the proper environment for this interpreter.
501 pub(super) fn subst_from_current_frame_and_normalize_erasing_regions
<T
: TypeFoldable
<'tcx
>>(
505 self.subst_from_frame_and_normalize_erasing_regions(self.frame(), value
)
508 /// Call this on things you got out of the MIR (so it is as generic as the provided
509 /// stack frame), to bring it into the proper environment for this interpreter.
510 pub(super) fn subst_from_frame_and_normalize_erasing_regions
<T
: TypeFoldable
<'tcx
>>(
512 frame
: &Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
>,
515 frame
.instance
.subst_mir_and_normalize_erasing_regions(*self.tcx
, self.param_env
, value
)
518 /// The `substs` are assumed to already be in our interpreter "universe" (param_env).
519 pub(super) fn resolve(
521 def
: ty
::WithOptConstParam
<DefId
>,
522 substs
: SubstsRef
<'tcx
>,
523 ) -> InterpResult
<'tcx
, ty
::Instance
<'tcx
>> {
524 trace
!("resolve: {:?}, {:#?}", def
, substs
);
525 trace
!("param_env: {:#?}", self.param_env
);
526 trace
!("substs: {:#?}", substs
);
527 match ty
::Instance
::resolve_opt_const_arg(*self.tcx
, self.param_env
, def
, substs
) {
528 Ok(Some(instance
)) => Ok(instance
),
529 Ok(None
) => throw_inval
!(TooGeneric
),
531 // FIXME(eddyb) this could be a bit more specific than `AlreadyReported`.
532 Err(error_reported
) => throw_inval
!(AlreadyReported(error_reported
)),
537 pub fn layout_of_local(
539 frame
: &Frame
<'mir
, 'tcx
, M
::PointerTag
, M
::FrameExtra
>,
541 layout
: Option
<TyAndLayout
<'tcx
>>,
542 ) -> InterpResult
<'tcx
, TyAndLayout
<'tcx
>> {
543 // `const_prop` runs into this with an invalid (empty) frame, so we
544 // have to support that case (mostly by skipping all caching).
545 match frame
.locals
.get(local
).and_then(|state
| state
.layout
.get()) {
547 let layout
= from_known_layout(self.tcx
, self.param_env
, layout
, || {
548 let local_ty
= frame
.body
.local_decls
[local
].ty
;
550 self.subst_from_frame_and_normalize_erasing_regions(frame
, local_ty
);
551 self.layout_of(local_ty
)
553 if let Some(state
) = frame
.locals
.get(local
) {
554 // Layouts of locals are requested a lot, so we cache them.
555 state
.layout
.set(Some(layout
));
559 Some(layout
) => Ok(layout
),
563 /// Returns the actual dynamic size and alignment of the place at the given type.
564 /// Only the "meta" (metadata) part of the place matters.
565 /// This can fail to provide an answer for extern types.
566 pub(super) fn size_and_align_of(
568 metadata
: &MemPlaceMeta
<M
::PointerTag
>,
569 layout
: &TyAndLayout
<'tcx
>,
570 ) -> InterpResult
<'tcx
, Option
<(Size
, Align
)>> {
571 if !layout
.is_unsized() {
572 return Ok(Some((layout
.size
, layout
.align
.abi
)));
574 match layout
.ty
.kind() {
575 ty
::Adt(..) | ty
::Tuple(..) => {
576 // First get the size of all statically known fields.
577 // Don't use type_of::sizing_type_of because that expects t to be sized,
578 // and it also rounds up to alignment, which we want to avoid,
579 // as the unsized field's alignment could be smaller.
580 assert
!(!layout
.ty
.is_simd());
581 assert
!(layout
.fields
.count() > 0);
582 trace
!("DST layout: {:?}", layout
);
584 let sized_size
= layout
.fields
.offset(layout
.fields
.count() - 1);
585 let sized_align
= layout
.align
.abi
;
587 "DST {} statically sized prefix size: {:?} align: {:?}",
593 // Recurse to get the size of the dynamically sized field (must be
594 // the last field). Can't have foreign types here, how would we
595 // adjust alignment and size for them?
596 let field
= layout
.field(self, layout
.fields
.count() - 1);
597 let (unsized_size
, unsized_align
) =
598 match self.size_and_align_of(metadata
, &field
)?
{
599 Some(size_and_align
) => size_and_align
,
601 // A field with extern type. If this field is at offset 0, we behave
602 // like the underlying extern type.
603 // FIXME: Once we have made decisions for how to handle size and alignment
604 // of `extern type`, this should be adapted. It is just a temporary hack
605 // to get some code to work that probably ought to work.
606 if sized_size
== Size
::ZERO
{
611 "Fields cannot be extern types, unless they are at offset 0"
617 // FIXME (#26403, #27023): We should be adding padding
618 // to `sized_size` (to accommodate the `unsized_align`
619 // required of the unsized field that follows) before
620 // summing it with `sized_size`. (Note that since #26403
621 // is unfixed, we do not yet add the necessary padding
622 // here. But this is where the add would go.)
624 // Return the sum of sizes and max of aligns.
625 let size
= sized_size
+ unsized_size
; // `Size` addition
627 // Choose max of two known alignments (combined value must
628 // be aligned according to more restrictive of the two).
629 let align
= sized_align
.max(unsized_align
);
631 // Issue #27023: must add any necessary padding to `size`
632 // (to make it a multiple of `align`) before returning it.
633 let size
= size
.align_to(align
);
635 // Check if this brought us over the size limit.
636 if size
.bytes() >= self.tcx
.data_layout
.obj_size_bound() {
637 throw_ub
!(InvalidMeta("total size is bigger than largest supported object"));
639 Ok(Some((size
, align
)))
642 let vtable
= self.scalar_to_ptr(metadata
.unwrap_meta());
643 // Read size and align from vtable (already checks size).
644 Ok(Some(self.read_size_and_align_from_vtable(vtable
)?
))
647 ty
::Slice(_
) | ty
::Str
=> {
648 let len
= metadata
.unwrap_meta().to_machine_usize(self)?
;
649 let elem
= layout
.field(self, 0);
651 // Make sure the slice is not too big.
652 let size
= elem
.size
.checked_mul(len
, self).ok_or_else(|| {
653 err_ub
!(InvalidMeta("slice is bigger than largest supported object"))
655 Ok(Some((size
, elem
.align
.abi
)))
658 ty
::Foreign(_
) => Ok(None
),
660 _
=> span_bug
!(self.cur_span(), "size_and_align_of::<{:?}> not supported", layout
.ty
),
664 pub fn size_and_align_of_mplace(
666 mplace
: &MPlaceTy
<'tcx
, M
::PointerTag
>,
667 ) -> InterpResult
<'tcx
, Option
<(Size
, Align
)>> {
668 self.size_and_align_of(&mplace
.meta
, &mplace
.layout
)
671 pub fn push_stack_frame(
673 instance
: ty
::Instance
<'tcx
>,
674 body
: &'mir mir
::Body
<'tcx
>,
675 return_place
: Option
<&PlaceTy
<'tcx
, M
::PointerTag
>>,
676 return_to_block
: StackPopCleanup
,
677 ) -> InterpResult
<'tcx
> {
678 // first push a stack frame so we have access to the local substs
679 let pre_frame
= Frame
{
681 loc
: Err(body
.span
), // Span used for errors caused during preamble.
683 return_place
: return_place
.copied(),
684 // empty local array, we fill it in below, after we are inside the stack frame and
685 // all methods actually know about the frame
686 locals
: IndexVec
::new(),
688 tracing_span
: SpanGuard
::new(),
691 let frame
= M
::init_frame_extra(self, pre_frame
)?
;
692 self.stack_mut().push(frame
);
694 // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check).
695 for const_
in &body
.required_consts
{
696 let span
= const_
.span
;
698 self.subst_from_current_frame_and_normalize_erasing_regions(const_
.literal
);
699 self.mir_const_to_op(&const_
, None
).map_err(|err
| {
700 // If there was an error, set the span of the current frame to this constant.
701 // Avoiding doing this when evaluation succeeds.
702 self.frame_mut().loc
= Err(span
);
707 // Locals are initially uninitialized.
708 let dummy
= LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) }
;
709 let mut locals
= IndexVec
::from_elem(dummy
, &body
.local_decls
);
711 // Now mark those locals as dead that we do not want to initialize
712 // Mark locals that use `Storage*` annotations as dead on function entry.
713 let always_live
= AlwaysLiveLocals
::new(self.body());
714 for local
in locals
.indices() {
715 if !always_live
.contains(local
) {
716 locals
[local
].value
= LocalValue
::Dead
;
720 self.frame_mut().locals
= locals
;
721 M
::after_stack_push(self)?
;
722 self.frame_mut().loc
= Ok(mir
::Location
::START
);
724 let span
= info_span
!("frame", "{}", instance
);
725 self.frame_mut().tracing_span
.enter(span
);
730 /// Jump to the given block.
732 pub fn go_to_block(&mut self, target
: mir
::BasicBlock
) {
733 self.frame_mut().loc
= Ok(mir
::Location { block: target, statement_index: 0 }
);
736 /// *Return* to the given `target` basic block.
737 /// Do *not* use for unwinding! Use `unwind_to_block` instead.
739 /// If `target` is `None`, that indicates the function cannot return, so we raise UB.
740 pub fn return_to_block(&mut self, target
: Option
<mir
::BasicBlock
>) -> InterpResult
<'tcx
> {
741 if let Some(target
) = target
{
742 self.go_to_block(target
);
745 throw_ub
!(Unreachable
)
749 /// *Unwind* to the given `target` basic block.
750 /// Do *not* use for returning! Use `return_to_block` instead.
752 /// If `target` is `StackPopUnwind::Skip`, that indicates the function does not need cleanup
753 /// during unwinding, and we will just keep propagating that upwards.
755 /// If `target` is `StackPopUnwind::NotAllowed`, that indicates the function does not allow
756 /// unwinding, and doing so is UB.
757 pub fn unwind_to_block(&mut self, target
: StackPopUnwind
) -> InterpResult
<'tcx
> {
758 self.frame_mut().loc
= match target
{
759 StackPopUnwind
::Cleanup(block
) => Ok(mir
::Location { block, statement_index: 0 }
),
760 StackPopUnwind
::Skip
=> Err(self.frame_mut().body
.span
),
761 StackPopUnwind
::NotAllowed
=> {
762 throw_ub_format
!("unwinding past a stack frame that does not allow unwinding")
768 /// Pops the current frame from the stack, deallocating the
769 /// memory for allocated locals.
771 /// If `unwinding` is `false`, then we are performing a normal return
772 /// from a function. In this case, we jump back into the frame of the caller,
773 /// and continue execution as normal.
775 /// If `unwinding` is `true`, then we are in the middle of a panic,
776 /// and need to unwind this frame. In this case, we jump to the
777 /// `cleanup` block for the function, which is responsible for running
778 /// `Drop` impls for any locals that have been initialized at this point.
779 /// The cleanup block ends with a special `Resume` terminator, which will
780 /// cause us to continue unwinding.
781 pub(super) fn pop_stack_frame(&mut self, unwinding
: bool
) -> InterpResult
<'tcx
> {
783 "popping stack frame ({})",
784 if unwinding { "during unwinding" }
else { "returning from function" }
787 // Sanity check `unwinding`.
790 match self.frame().loc
{
791 Ok(loc
) => self.body().basic_blocks()[loc
.block
].is_cleanup
,
796 if unwinding
&& self.frame_idx() == 0 {
797 throw_ub_format
!("unwinding past the topmost frame of the stack");
801 self.stack_mut().pop().expect("tried to pop a stack frame, but there were none");
804 // Copy the return value to the caller's stack frame.
805 if let Some(ref return_place
) = frame
.return_place
{
806 let op
= self.access_local(&frame
, mir
::RETURN_PLACE
, None
)?
;
807 self.copy_op_transmute(&op
, return_place
)?
;
808 trace
!("{:?}", self.dump_place(**return_place
));
810 throw_ub
!(Unreachable
);
814 let return_to_block
= frame
.return_to_block
;
816 // Now where do we jump next?
818 // Usually we want to clean up (deallocate locals), but in a few rare cases we don't.
819 // In that case, we return early. We also avoid validation in that case,
820 // because this is CTFE and the final value will be thoroughly validated anyway.
821 let cleanup
= match return_to_block
{
822 StackPopCleanup
::Goto { .. }
=> true,
823 StackPopCleanup
::None { cleanup, .. }
=> cleanup
,
827 assert
!(self.stack().is_empty(), "only the topmost frame should ever be leaked");
828 assert
!(!unwinding
, "tried to skip cleanup during unwinding");
829 // Leak the locals, skip validation, skip machine hook.
833 // Cleanup: deallocate all locals that are backed by an allocation.
834 for local
in &frame
.locals
{
835 self.deallocate_local(local
.value
)?
;
838 if M
::after_stack_pop(self, frame
, unwinding
)?
== StackPopJump
::NoJump
{
839 // The hook already did everything.
840 // We want to skip the `info!` below, hence early return.
843 // Normal return, figure out where to jump.
845 // Follow the unwind edge.
846 let unwind
= match return_to_block
{
847 StackPopCleanup
::Goto { unwind, .. }
=> unwind
,
848 StackPopCleanup
::None { .. }
=> {
849 panic
!("Encountered StackPopCleanup::None when unwinding!")
852 self.unwind_to_block(unwind
)
854 // Follow the normal return edge.
855 match return_to_block
{
856 StackPopCleanup
::Goto { ret, .. }
=> self.return_to_block(ret
),
857 StackPopCleanup
::None { .. }
=> Ok(()),
862 /// Mark a storage as live, killing the previous content.
863 pub fn storage_live(&mut self, local
: mir
::Local
) -> InterpResult
<'tcx
> {
864 assert
!(local
!= mir
::RETURN_PLACE
, "Cannot make return place live");
865 trace
!("{:?} is now live", local
);
867 let local_val
= LocalValue
::Uninitialized
;
868 // StorageLive expects the local to be dead, and marks it live.
869 let old
= mem
::replace(&mut self.frame_mut().locals
[local
].value
, local_val
);
870 if !matches
!(old
, LocalValue
::Dead
) {
871 throw_ub_format
!("StorageLive on a local that was already live");
876 pub fn storage_dead(&mut self, local
: mir
::Local
) -> InterpResult
<'tcx
> {
877 assert
!(local
!= mir
::RETURN_PLACE
, "Cannot make return place dead");
878 trace
!("{:?} is now dead", local
);
880 // It is entirely okay for this local to be already dead (at least that's how we currently generate MIR)
881 let old
= mem
::replace(&mut self.frame_mut().locals
[local
].value
, LocalValue
::Dead
);
882 self.deallocate_local(old
)?
;
886 fn deallocate_local(&mut self, local
: LocalValue
<M
::PointerTag
>) -> InterpResult
<'tcx
> {
887 if let LocalValue
::Live(Operand
::Indirect(MemPlace { ptr, .. }
)) = local
{
888 // All locals have a backing allocation, even if the allocation is empty
889 // due to the local having ZST type. Hence we can `unwrap`.
891 "deallocating local {:?}: {:?}",
893 self.memory
.dump_alloc(ptr
.provenance
.unwrap().get_alloc_id())
895 self.memory
.deallocate(ptr
, None
, MemoryKind
::Stack
)?
;
900 pub fn eval_to_allocation(
903 ) -> InterpResult
<'tcx
, MPlaceTy
<'tcx
, M
::PointerTag
>> {
904 // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
905 // and thus don't care about the parameter environment. While we could just use
906 // `self.param_env`, that would mean we invoke the query to evaluate the static
907 // with different parameter environments, thus causing the static to be evaluated
909 let param_env
= if self.tcx
.is_static(gid
.instance
.def_id()) {
910 ty
::ParamEnv
::reveal_all()
914 let val
= self.tcx
.eval_to_allocation_raw(param_env
.and(gid
))?
;
915 self.raw_const_to_mplace(val
)
919 pub fn dump_place(&'a
self, place
: Place
<M
::PointerTag
>) -> PlacePrinter
<'a
, 'mir
, 'tcx
, M
> {
920 PlacePrinter { ecx: self, place }
924 pub fn generate_stacktrace(&self) -> Vec
<FrameInfo
<'tcx
>> {
925 let mut frames
= Vec
::new();
930 .skip_while(|frame
| frame
.instance
.def
.requires_caller_location(*self.tcx
))
932 let lint_root
= frame
.current_source_info().and_then(|source_info
| {
933 match &frame
.body
.source_scopes
[source_info
.scope
].local_data
{
934 mir
::ClearCrossCrate
::Set(data
) => Some(data
.lint_root
),
935 mir
::ClearCrossCrate
::Clear
=> None
,
938 let span
= frame
.current_span();
940 frames
.push(FrameInfo { span, instance: frame.instance, lint_root }
);
942 trace
!("generate stacktrace: {:#?}", frames
);
948 /// Helper struct for the `dump_place` function.
949 pub struct PlacePrinter
<'a
, 'mir
, 'tcx
, M
: Machine
<'mir
, 'tcx
>> {
950 ecx
: &'a InterpCx
<'mir
, 'tcx
, M
>,
951 place
: Place
<M
::PointerTag
>,
954 impl<'a
, 'mir
, 'tcx
: 'mir
, M
: Machine
<'mir
, 'tcx
>> std
::fmt
::Debug
955 for PlacePrinter
<'a
, 'mir
, 'tcx
, M
>
957 fn fmt(&self, fmt
: &mut std
::fmt
::Formatter
<'_
>) -> std
::fmt
::Result
{
959 Place
::Local { frame, local }
=> {
960 let mut allocs
= Vec
::new();
961 write
!(fmt
, "{:?}", local
)?
;
962 if frame
!= self.ecx
.frame_idx() {
963 write
!(fmt
, " ({} frames up)", self.ecx
.frame_idx() - frame
)?
;
967 match self.ecx
.stack()[frame
].locals
[local
].value
{
968 LocalValue
::Dead
=> write
!(fmt
, " is dead")?
,
969 LocalValue
::Uninitialized
=> write
!(fmt
, " is uninitialized")?
,
970 LocalValue
::Live(Operand
::Indirect(mplace
)) => {
973 " by align({}){} ref {:?}:",
974 mplace
.align
.bytes(),
976 MemPlaceMeta
::Meta(meta
) => format
!(" meta({:?})", meta
),
977 MemPlaceMeta
::Poison
| MemPlaceMeta
::None
=> String
::new(),
981 allocs
.extend(mplace
.ptr
.provenance
.map(Provenance
::get_alloc_id
));
983 LocalValue
::Live(Operand
::Immediate(Immediate
::Scalar(val
))) => {
984 write
!(fmt
, " {:?}", val
)?
;
985 if let ScalarMaybeUninit
::Scalar(Scalar
::Ptr(ptr
, _size
)) = val
{
986 allocs
.push(ptr
.provenance
.get_alloc_id());
989 LocalValue
::Live(Operand
::Immediate(Immediate
::ScalarPair(val1
, val2
))) => {
990 write
!(fmt
, " ({:?}, {:?})", val1
, val2
)?
;
991 if let ScalarMaybeUninit
::Scalar(Scalar
::Ptr(ptr
, _size
)) = val1
{
992 allocs
.push(ptr
.provenance
.get_alloc_id());
994 if let ScalarMaybeUninit
::Scalar(Scalar
::Ptr(ptr
, _size
)) = val2
{
995 allocs
.push(ptr
.provenance
.get_alloc_id());
1000 write
!(fmt
, ": {:?}", self.ecx
.memory
.dump_allocs(allocs
))
1002 Place
::Ptr(mplace
) => match mplace
.ptr
.provenance
.map(Provenance
::get_alloc_id
) {
1003 Some(alloc_id
) => write
!(
1005 "by align({}) ref {:?}: {:?}",
1006 mplace
.align
.bytes(),
1008 self.ecx
.memory
.dump_alloc(alloc_id
)
1010 ptr
=> write
!(fmt
, " integral by ref: {:?}", ptr
),
1016 impl<'ctx
, 'mir
, 'tcx
, Tag
: Provenance
, Extra
> HashStable
<StableHashingContext
<'ctx
>>
1017 for Frame
<'mir
, 'tcx
, Tag
, Extra
>
1019 Extra
: HashStable
<StableHashingContext
<'ctx
>>,
1020 Tag
: HashStable
<StableHashingContext
<'ctx
>>,
1022 fn hash_stable(&self, hcx
: &mut StableHashingContext
<'ctx
>, hasher
: &mut StableHasher
) {
1023 // Exhaustive match on fields to make sure we forget no field.
1034 body
.hash_stable(hcx
, hasher
);
1035 instance
.hash_stable(hcx
, hasher
);
1036 return_to_block
.hash_stable(hcx
, hasher
);
1037 return_place
.as_ref().map(|r
| &**r
).hash_stable(hcx
, hasher
);
1038 locals
.hash_stable(hcx
, hasher
);
1039 loc
.hash_stable(hcx
, hasher
);
1040 extra
.hash_stable(hcx
, hasher
);