5 use rustc::ich::StableHashingContext;
7 use rustc::mir::interpret::{
8 sign_extend, truncate, AllocId, FrameInfo, GlobalId, InterpResult, Pointer, Scalar,
10 use rustc::ty::layout::{self, Align, HasDataLayout, LayoutOf, Size, TyLayout};
11 use rustc::ty::query::TyCtxtAt;
12 use rustc::ty::subst::SubstsRef;
13 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
14 use rustc_data_structures::fx::FxHashMap;
15 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
16 use rustc_hir::def::DefKind;
17 use rustc_hir::def_id::DefId;
18 use rustc_index::vec::IndexVec;
19 use rustc_macros::HashStable;
20 use rustc_span::source_map::{self, Span, DUMMY_SP};
23 Immediate, MPlaceTy, Machine, MemPlace, MemPlaceMeta, Memory, OpTy, Operand, Place, PlaceTy,
24 ScalarMaybeUndef, StackPopInfo,
27 pub struct InterpCx<'mir, 'tcx, M: Machine<'mir, 'tcx>> {
28 /// Stores the `Machine` instance.
31 /// The results of the type checker, from rustc.
32 pub tcx: TyCtxtAt<'tcx>,
34 /// Bounds in scope for polymorphic evaluations.
35 pub(crate) param_env: ty::ParamEnv<'tcx>,
37 /// The virtual memory system.
38 pub memory: Memory<'mir, 'tcx, M>,
40 /// The virtual call stack.
41 pub(crate) stack: Vec<Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>>,
43 /// A cache for deduplicating vtables
45 FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), Pointer<M::PointerTag>>,
50 pub struct Frame<'mir, 'tcx, Tag = (), Extra = ()> {
51 ////////////////////////////////////////////////////////////////////////////////
52 // Function and callsite information
53 ////////////////////////////////////////////////////////////////////////////////
54 /// The MIR for the function called on this frame.
55 pub body: &'mir mir::Body<'tcx>,
57 /// The def_id and substs of the current function.
58 pub instance: ty::Instance<'tcx>,
60 /// The span of the call site.
61 pub span: source_map::Span,
63 /// Extra data for the machine.
66 ////////////////////////////////////////////////////////////////////////////////
67 // Return place and locals
68 ////////////////////////////////////////////////////////////////////////////////
69 /// Work to perform when returning from this function.
70 pub return_to_block: StackPopCleanup,
72 /// The location where the result of the current stack frame should be written to,
73 /// and its layout in the caller.
74 pub return_place: Option<PlaceTy<'tcx, Tag>>,
76 /// The list of locals for this stack frame, stored in order as
77 /// `[return_ptr, arguments..., variables..., temporaries...]`.
78 /// The locals are stored as `Option<Value>`s.
79 /// `None` represents a local that is currently dead, while a live local
80 /// can either directly contain `Scalar` or refer to some part of an `Allocation`.
81 pub locals: IndexVec<mir::Local, LocalState<'tcx, Tag>>,
83 ////////////////////////////////////////////////////////////////////////////////
84 // Current position within the function
85 ////////////////////////////////////////////////////////////////////////////////
86 /// The block that is currently executed (or will be executed after the above call stacks
88 /// If this is `None`, we are unwinding and this function doesn't need any clean-up.
89 /// Just continue the same as with `Resume`.
90 pub block: Option<mir::BasicBlock>,
92 /// The index of the currently evaluated statement.
96 #[derive(Clone, Eq, PartialEq, Debug, HashStable)] // Miri debug-prints these
97 pub enum StackPopCleanup {
98 /// Jump to the next block in the caller, or cause UB if None (that's a function
99 /// that may never return). Also store layout of return place so
100 /// we can validate it at that layout.
101 /// `ret` stores the block we jump to on a normal return, while 'unwind'
102 /// stores the block used for cleanup during unwinding
103 Goto { ret: Option<mir::BasicBlock>, unwind: Option<mir::BasicBlock> },
104 /// Just do nohing: Used by Main and for the box_alloc hook in miri.
105 /// `cleanup` says whether locals are deallocated. Static computation
106 /// wants them leaked to intern what they need (and just throw away
107 /// the entire `ecx` when it is done).
108 None { cleanup: bool },
111 /// State of a local variable including a memoized layout
112 #[derive(Clone, PartialEq, Eq, HashStable)]
113 pub struct LocalState<'tcx, Tag = (), Id = AllocId> {
114 pub value: LocalValue<Tag, Id>,
115 /// Don't modify if `Some`, this is only used to prevent computing the layout twice
116 #[stable_hasher(ignore)]
117 pub layout: Cell<Option<TyLayout<'tcx>>>,
120 /// Current value of a local variable
121 #[derive(Copy, Clone, PartialEq, Eq, Debug, HashStable)] // Miri debug-prints these
122 pub enum LocalValue<Tag = (), Id = AllocId> {
123 /// This local is not currently alive, and cannot be used at all.
125 /// This local is alive but not yet initialized. It can be written to
126 /// but not read from or its address taken. Locals get initialized on
127 /// first write because for unsized locals, we do not know their size
130 /// A normal, live local.
131 /// Mostly for convenience, we re-use the `Operand` type here.
132 /// This is an optimization over just always having a pointer here;
133 /// we can thus avoid doing an allocation when the local just stores
134 /// immediate values *and* never has its address taken.
135 Live(Operand<Tag, Id>),
138 impl<'tcx, Tag: Copy + 'static> LocalState<'tcx, Tag> {
139 pub fn access(&self) -> InterpResult<'tcx, Operand<Tag>> {
141 LocalValue::Dead => throw_unsup!(DeadLocal),
142 LocalValue::Uninitialized => {
143 bug!("The type checker should prevent reading from a never-written local")
145 LocalValue::Live(val) => Ok(val),
149 /// Overwrite the local. If the local can be overwritten in place, return a reference
150 /// to do so; otherwise return the `MemPlace` to consult instead.
153 ) -> InterpResult<'tcx, Result<&mut LocalValue<Tag>, MemPlace<Tag>>> {
155 LocalValue::Dead => throw_unsup!(DeadLocal),
156 LocalValue::Live(Operand::Indirect(mplace)) => Ok(Err(mplace)),
157 ref mut local @ LocalValue::Live(Operand::Immediate(_))
158 | ref mut local @ LocalValue::Uninitialized => Ok(Ok(local)),
163 impl<'mir, 'tcx, Tag, Extra> Frame<'mir, 'tcx, Tag, Extra> {
164 /// Return the `SourceInfo` of the current instruction.
165 pub fn current_source_info(&self) -> Option<mir::SourceInfo> {
166 self.block.map(|block| {
167 let block = &self.body.basic_blocks()[block];
168 if self.stmt < block.statements.len() {
169 block.statements[self.stmt].source_info
171 block.terminator().source_info
177 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> HasDataLayout for InterpCx<'mir, 'tcx, M> {
179 fn data_layout(&self) -> &layout::TargetDataLayout {
180 &self.tcx.data_layout
184 impl<'mir, 'tcx, M> layout::HasTyCtxt<'tcx> for InterpCx<'mir, 'tcx, M>
186 M: Machine<'mir, 'tcx>,
189 fn tcx(&self) -> TyCtxt<'tcx> {
194 impl<'mir, 'tcx, M> layout::HasParamEnv<'tcx> for InterpCx<'mir, 'tcx, M>
196 M: Machine<'mir, 'tcx>,
198 fn param_env(&self) -> ty::ParamEnv<'tcx> {
203 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> LayoutOf for InterpCx<'mir, 'tcx, M> {
205 type TyLayout = InterpResult<'tcx, TyLayout<'tcx>>;
208 fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
210 .layout_of(self.param_env.and(ty))
211 .map_err(|layout| err_inval!(Layout(layout)).into())
215 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
218 param_env: ty::ParamEnv<'tcx>,
220 memory_extra: M::MemoryExtra,
226 memory: Memory::new(tcx, memory_extra),
228 vtables: FxHashMap::default(),
235 scalar: Scalar<M::PointerTag>,
236 ) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
237 self.memory.force_ptr(scalar)
243 scalar: Scalar<M::PointerTag>,
245 ) -> InterpResult<'tcx, u128> {
246 self.memory.force_bits(scalar, size)
249 /// Call this to turn untagged "global" pointers (obtained via `tcx`) into
250 /// the *canonical* machine pointer to the allocation. Must never be used
251 /// for any other pointers!
253 /// This represents a *direct* access to that memory, as opposed to access
254 /// through a pointer that was created by the program.
256 pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
257 self.memory.tag_static_base_pointer(ptr)
261 pub fn stack(&self) -> &[Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>] {
266 pub fn cur_frame(&self) -> usize {
267 assert!(!self.stack.is_empty());
272 pub fn frame(&self) -> &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
273 self.stack.last().expect("no call frames exist")
277 pub fn frame_mut(&mut self) -> &mut Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
278 self.stack.last_mut().expect("no call frames exist")
282 pub(super) fn body(&self) -> &'mir mir::Body<'tcx> {
287 pub fn sign_extend(&self, value: u128, ty: TyLayout<'_>) -> u128 {
288 assert!(ty.abi.is_signed());
289 sign_extend(value, ty.size)
293 pub fn truncate(&self, value: u128, ty: TyLayout<'_>) -> u128 {
294 truncate(value, ty.size)
298 pub fn type_is_sized(&self, ty: Ty<'tcx>) -> bool {
299 ty.is_sized(self.tcx, self.param_env)
303 pub fn type_is_freeze(&self, ty: Ty<'tcx>) -> bool {
304 ty.is_freeze(*self.tcx, self.param_env, DUMMY_SP)
309 instance: ty::InstanceDef<'tcx>,
310 promoted: Option<mir::Promoted>,
311 ) -> InterpResult<'tcx, mir::ReadOnlyBodyAndCache<'tcx, 'tcx>> {
312 // do not continue if typeck errors occurred (can only occur in local crate)
313 let did = instance.def_id();
315 && self.tcx.has_typeck_tables(did)
316 && self.tcx.typeck_tables_of(did).tainted_by_errors
318 throw_inval!(TypeckError)
320 trace!("load mir(instance={:?}, promoted={:?})", instance, promoted);
321 if let Some(promoted) = promoted {
322 return Ok(self.tcx.promoted_mir(did)[promoted].unwrap_read_only());
325 ty::InstanceDef::Item(def_id) => {
326 if self.tcx.is_mir_available(did) {
327 Ok(self.tcx.optimized_mir(did).unwrap_read_only())
329 throw_unsup!(NoMirFor(self.tcx.def_path_str(def_id)))
332 _ => Ok(self.tcx.instance_mir(instance)),
336 /// Call this on things you got out of the MIR (so it is as generic as the current
337 /// stack frame), to bring it into the proper environment for this interpreter.
338 pub(super) fn subst_from_frame_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
342 self.tcx.subst_and_normalize_erasing_regions(
343 self.frame().instance.substs,
349 /// The `substs` are assumed to already be in our interpreter "universe" (param_env).
350 pub(super) fn resolve(
353 substs: SubstsRef<'tcx>,
354 ) -> InterpResult<'tcx, ty::Instance<'tcx>> {
355 trace!("resolve: {:?}, {:#?}", def_id, substs);
356 trace!("param_env: {:#?}", self.param_env);
357 trace!("substs: {:#?}", substs);
358 ty::Instance::resolve(*self.tcx, self.param_env, def_id, substs)
359 .ok_or_else(|| err_inval!(TooGeneric).into())
362 pub fn layout_of_local(
364 frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
366 layout: Option<TyLayout<'tcx>>,
367 ) -> InterpResult<'tcx, TyLayout<'tcx>> {
368 // `const_prop` runs into this with an invalid (empty) frame, so we
369 // have to support that case (mostly by skipping all caching).
370 match frame.locals.get(local).and_then(|state| state.layout.get()) {
372 let layout = crate::interpret::operand::from_known_layout(layout, || {
373 let local_ty = frame.body.local_decls[local].ty;
374 let local_ty = self.tcx.subst_and_normalize_erasing_regions(
375 frame.instance.substs,
379 self.layout_of(local_ty)
381 if let Some(state) = frame.locals.get(local) {
382 // Layouts of locals are requested a lot, so we cache them.
383 state.layout.set(Some(layout));
387 Some(layout) => Ok(layout),
391 /// Returns the actual dynamic size and alignment of the place at the given type.
392 /// Only the "meta" (metadata) part of the place matters.
393 /// This can fail to provide an answer for extern types.
394 pub(super) fn size_and_align_of(
396 metadata: MemPlaceMeta<M::PointerTag>,
397 layout: TyLayout<'tcx>,
398 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
399 if !layout.is_unsized() {
400 return Ok(Some((layout.size, layout.align.abi)));
402 match layout.ty.kind {
403 ty::Adt(..) | ty::Tuple(..) => {
404 // First get the size of all statically known fields.
405 // Don't use type_of::sizing_type_of because that expects t to be sized,
406 // and it also rounds up to alignment, which we want to avoid,
407 // as the unsized field's alignment could be smaller.
408 assert!(!layout.ty.is_simd());
409 trace!("DST layout: {:?}", layout);
411 let sized_size = layout.fields.offset(layout.fields.count() - 1);
412 let sized_align = layout.align.abi;
414 "DST {} statically sized prefix size: {:?} align: {:?}",
420 // Recurse to get the size of the dynamically sized field (must be
421 // the last field). Can't have foreign types here, how would we
422 // adjust alignment and size for them?
423 let field = layout.field(self, layout.fields.count() - 1)?;
424 let (unsized_size, unsized_align) = match self.size_and_align_of(metadata, field)? {
425 Some(size_and_align) => size_and_align,
427 // A field with extern type. If this field is at offset 0, we behave
428 // like the underlying extern type.
429 // FIXME: Once we have made decisions for how to handle size and alignment
430 // of `extern type`, this should be adapted. It is just a temporary hack
431 // to get some code to work that probably ought to work.
432 if sized_size == Size::ZERO {
435 bug!("Fields cannot be extern types, unless they are at offset 0")
440 // FIXME (#26403, #27023): We should be adding padding
441 // to `sized_size` (to accommodate the `unsized_align`
442 // required of the unsized field that follows) before
443 // summing it with `sized_size`. (Note that since #26403
444 // is unfixed, we do not yet add the necessary padding
445 // here. But this is where the add would go.)
447 // Return the sum of sizes and max of aligns.
448 let size = sized_size + unsized_size;
450 // Choose max of two known alignments (combined value must
451 // be aligned according to more restrictive of the two).
452 let align = sized_align.max(unsized_align);
454 // Issue #27023: must add any necessary padding to `size`
455 // (to make it a multiple of `align`) before returning it.
456 let size = size.align_to(align);
458 // Check if this brought us over the size limit.
459 if size.bytes() >= self.tcx.data_layout().obj_size_bound() {
461 "wide pointer metadata contains invalid information: \
462 total size is bigger than largest supported object"
465 Ok(Some((size, align)))
468 let vtable = metadata.unwrap_meta();
469 // Read size and align from vtable (already checks size).
470 Ok(Some(self.read_size_and_align_from_vtable(vtable)?))
473 ty::Slice(_) | ty::Str => {
474 let len = metadata.unwrap_meta().to_machine_usize(self)?;
475 let elem = layout.field(self, 0)?;
477 // Make sure the slice is not too big.
478 let size = elem.size.checked_mul(len, &*self.tcx).ok_or_else(|| {
481 total size is bigger than largest supported object"
484 Ok(Some((size, elem.align.abi)))
487 ty::Foreign(_) => Ok(None),
489 _ => bug!("size_and_align_of::<{:?}> not supported", layout.ty),
493 pub fn size_and_align_of_mplace(
495 mplace: MPlaceTy<'tcx, M::PointerTag>,
496 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
497 self.size_and_align_of(mplace.meta, mplace.layout)
500 pub fn push_stack_frame(
502 instance: ty::Instance<'tcx>,
504 body: &'mir mir::Body<'tcx>,
505 return_place: Option<PlaceTy<'tcx, M::PointerTag>>,
506 return_to_block: StackPopCleanup,
507 ) -> InterpResult<'tcx> {
508 if !self.stack.is_empty() {
509 info!("PAUSING({}) {}", self.cur_frame(), self.frame().instance);
511 ::log_settings::settings().indentation += 1;
513 // first push a stack frame so we have access to the local substs
514 let extra = M::stack_push(self)?;
515 self.stack.push(Frame {
517 block: Some(mir::START_BLOCK),
520 // empty local array, we fill it in below, after we are inside the stack frame and
521 // all methods actually know about the frame
522 locals: IndexVec::new(),
529 // don't allocate at all for trivial constants
530 if body.local_decls.len() > 1 {
531 // Locals are initially uninitialized.
532 let dummy = LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) };
533 let mut locals = IndexVec::from_elem(dummy, &body.local_decls);
534 // Return place is handled specially by the `eval_place` functions, and the
535 // entry in `locals` should never be used. Make it dead, to be sure.
536 locals[mir::RETURN_PLACE].value = LocalValue::Dead;
537 // Now mark those locals as dead that we do not want to initialize
538 match self.tcx.def_kind(instance.def_id()) {
539 // statics and constants don't have `Storage*` statements, no need to look for them
540 Some(DefKind::Static) | Some(DefKind::Const) | Some(DefKind::AssocConst) => {}
542 trace!("push_stack_frame: {:?}: num_bbs: {}", span, body.basic_blocks().len());
543 for block in body.basic_blocks() {
544 for stmt in block.statements.iter() {
545 use rustc::mir::StatementKind::{StorageDead, StorageLive};
547 StorageLive(local) | StorageDead(local) => {
548 locals[local].value = LocalValue::Dead;
557 self.frame_mut().locals = locals;
560 info!("ENTERING({}) {}", self.cur_frame(), self.frame().instance);
562 if self.stack.len() > *self.tcx.sess.recursion_limit.get() {
563 throw_exhaust!(StackFrameLimitReached)
569 /// Jump to the given block.
571 pub fn go_to_block(&mut self, target: mir::BasicBlock) {
572 let frame = self.frame_mut();
573 frame.block = Some(target);
577 /// *Return* to the given `target` basic block.
578 /// Do *not* use for unwinding! Use `unwind_to_block` instead.
580 /// If `target` is `None`, that indicates the function cannot return, so we raise UB.
581 pub fn return_to_block(&mut self, target: Option<mir::BasicBlock>) -> InterpResult<'tcx> {
582 if let Some(target) = target {
583 Ok(self.go_to_block(target))
585 throw_ub!(Unreachable)
589 /// *Unwind* to the given `target` basic block.
590 /// Do *not* use for returning! Use `return_to_block` instead.
592 /// If `target` is `None`, that indicates the function does not need cleanup during
593 /// unwinding, and we will just keep propagating that upwards.
594 pub fn unwind_to_block(&mut self, target: Option<mir::BasicBlock>) {
595 let frame = self.frame_mut();
596 frame.block = target;
600 /// Pops the current frame from the stack, deallocating the
601 /// memory for allocated locals.
603 /// If `unwinding` is `false`, then we are performing a normal return
604 /// from a function. In this case, we jump back into the frame of the caller,
605 /// and continue execution as normal.
607 /// If `unwinding` is `true`, then we are in the middle of a panic,
608 /// and need to unwind this frame. In this case, we jump to the
609 /// `cleanup` block for the function, which is responsible for running
610 /// `Drop` impls for any locals that have been initialized at this point.
611 /// The cleanup block ends with a special `Resume` terminator, which will
612 /// cause us to continue unwinding.
613 pub(super) fn pop_stack_frame(&mut self, unwinding: bool) -> InterpResult<'tcx> {
615 "LEAVING({}) {} (unwinding = {})",
617 self.frame().instance,
621 // Sanity check `unwinding`.
624 match self.frame().block {
626 Some(block) => self.body().basic_blocks()[block].is_cleanup,
630 ::log_settings::settings().indentation -= 1;
631 let frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
632 let stack_pop_info = M::stack_pop(self, frame.extra, unwinding)?;
633 if let (false, StackPopInfo::StopUnwinding) = (unwinding, stack_pop_info) {
634 bug!("Attempted to stop unwinding while there is no unwinding!");
637 // Now where do we jump next?
639 // Determine if we leave this function normally or via unwinding.
641 if let StackPopInfo::StopUnwinding = stack_pop_info { false } else { unwinding };
643 // Usually we want to clean up (deallocate locals), but in a few rare cases we don't.
644 // In that case, we return early. We also avoid validation in that case,
645 // because this is CTFE and the final value will be thoroughly validated anyway.
646 let (cleanup, next_block) = match frame.return_to_block {
647 StackPopCleanup::Goto { ret, unwind } => {
648 (true, Some(if cur_unwinding { unwind } else { ret }))
650 StackPopCleanup::None { cleanup, .. } => (cleanup, None),
654 assert!(self.stack.is_empty(), "only the topmost frame should ever be leaked");
655 assert!(next_block.is_none(), "tried to skip cleanup when we have a next block!");
656 // Leak the locals, skip validation.
660 // Cleanup: deallocate all locals that are backed by an allocation.
661 for local in frame.locals {
662 self.deallocate_local(local.value)?;
666 "StackPopCleanup: {:?} StackPopInfo: {:?} cur_unwinding = {:?}",
667 frame.return_to_block,
672 // Follow the unwind edge.
673 let unwind = next_block.expect("Encounted StackPopCleanup::None when unwinding!");
674 self.unwind_to_block(unwind);
676 // Follow the normal return edge.
677 // Validate the return value. Do this after deallocating so that we catch dangling
679 if let Some(return_place) = frame.return_place {
680 if M::enforce_validity(self) {
681 // Data got changed, better make sure it matches the type!
682 // It is still possible that the return place held invalid data while
683 // the function is running, but that's okay because nobody could have
684 // accessed that same data from the "outside" to observe any broken
685 // invariant -- that is, unless a function somehow has a ptr to
686 // its return place... but the way MIR is currently generated, the
687 // return place is always a local and then this cannot happen.
688 self.validate_operand(self.place_to_op(return_place)?, vec![], None)?;
691 // Uh, that shouldn't happen... the function did not intend to return
692 throw_ub!(Unreachable);
695 // Jump to new block -- *after* validation so that the spans make more sense.
696 if let Some(ret) = next_block {
697 self.return_to_block(ret)?;
701 if !self.stack.is_empty() {
703 "CONTINUING({}) {} (unwinding = {})",
705 self.frame().instance,
713 /// Mark a storage as live, killing the previous content and returning it.
714 /// Remember to deallocate that!
718 ) -> InterpResult<'tcx, LocalValue<M::PointerTag>> {
719 assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
720 trace!("{:?} is now live", local);
722 let local_val = LocalValue::Uninitialized;
723 // StorageLive *always* kills the value that's currently stored.
724 // However, we do not error if the variable already is live;
725 // see <https://github.com/rust-lang/rust/issues/42371>.
726 Ok(mem::replace(&mut self.frame_mut().locals[local].value, local_val))
729 /// Returns the old value of the local.
730 /// Remember to deallocate that!
731 pub fn storage_dead(&mut self, local: mir::Local) -> LocalValue<M::PointerTag> {
732 assert!(local != mir::RETURN_PLACE, "Cannot make return place dead");
733 trace!("{:?} is now dead", local);
735 mem::replace(&mut self.frame_mut().locals[local].value, LocalValue::Dead)
738 pub(super) fn deallocate_local(
740 local: LocalValue<M::PointerTag>,
741 ) -> InterpResult<'tcx> {
742 // FIXME: should we tell the user that there was a local which was never written to?
743 if let LocalValue::Live(Operand::Indirect(MemPlace { ptr, .. })) = local {
744 trace!("deallocating local");
745 // All locals have a backing allocation, even if the allocation is empty
746 // due to the local having ZST type.
747 let ptr = ptr.assert_ptr();
748 if log_enabled!(::log::Level::Trace) {
749 self.memory.dump_alloc(ptr.alloc_id);
751 self.memory.deallocate_local(ptr)?;
756 pub(super) fn const_eval(
760 ) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
761 // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
762 // and thus don't care about the parameter environment. While we could just use
763 // `self.param_env`, that would mean we invoke the query to evaluate the static
764 // with different parameter environments, thus causing the static to be evaluated
766 let param_env = if self.tcx.is_static(gid.instance.def_id()) {
767 ty::ParamEnv::reveal_all()
771 let val = self.tcx.const_eval_global_id(param_env, gid, Some(self.tcx.span))?;
773 // Even though `ecx.const_eval` is called from `eval_const_to_op` we can never have a
774 // recursion deeper than one level, because the `tcx.const_eval` above is guaranteed to not
775 // return `ConstValue::Unevaluated`, which is the only way that `eval_const_to_op` will call
777 let const_ = ty::Const { val: ty::ConstKind::Value(val), ty };
778 self.eval_const_to_op(&const_, None)
781 pub fn const_eval_raw(
784 ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
785 // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
786 // and thus don't care about the parameter environment. While we could just use
787 // `self.param_env`, that would mean we invoke the query to evaluate the static
788 // with different parameter environments, thus causing the static to be evaluated
790 let param_env = if self.tcx.is_static(gid.instance.def_id()) {
791 ty::ParamEnv::reveal_all()
795 // We use `const_eval_raw` here, and get an unvalidated result. That is okay:
796 // Our result will later be validated anyway, and there seems no good reason
797 // to have to fail early here. This is also more consistent with
798 // `Memory::get_static_alloc` which has to use `const_eval_raw` to avoid cycles.
799 let val = self.tcx.const_eval_raw(param_env.and(gid))?;
800 self.raw_const_to_mplace(val)
803 pub fn dump_place(&self, place: Place<M::PointerTag>) {
805 if !log_enabled!(::log::Level::Trace) {
809 Place::Local { frame, local } => {
810 let mut allocs = Vec::new();
811 let mut msg = format!("{:?}", local);
812 if frame != self.cur_frame() {
813 write!(msg, " ({} frames up)", self.cur_frame() - frame).unwrap();
815 write!(msg, ":").unwrap();
817 match self.stack[frame].locals[local].value {
818 LocalValue::Dead => write!(msg, " is dead").unwrap(),
819 LocalValue::Uninitialized => write!(msg, " is uninitialized").unwrap(),
820 LocalValue::Live(Operand::Indirect(mplace)) => match mplace.ptr {
821 Scalar::Ptr(ptr) => {
824 " by align({}){} ref:",
825 mplace.align.bytes(),
827 MemPlaceMeta::Meta(meta) => format!(" meta({:?})", meta),
828 MemPlaceMeta::Poison | MemPlaceMeta::None => String::new(),
832 allocs.push(ptr.alloc_id);
834 ptr => write!(msg, " by integral ref: {:?}", ptr).unwrap(),
836 LocalValue::Live(Operand::Immediate(Immediate::Scalar(val))) => {
837 write!(msg, " {:?}", val).unwrap();
838 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val {
839 allocs.push(ptr.alloc_id);
842 LocalValue::Live(Operand::Immediate(Immediate::ScalarPair(val1, val2))) => {
843 write!(msg, " ({:?}, {:?})", val1, val2).unwrap();
844 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val1 {
845 allocs.push(ptr.alloc_id);
847 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val2 {
848 allocs.push(ptr.alloc_id);
854 self.memory.dump_allocs(allocs);
856 Place::Ptr(mplace) => match mplace.ptr {
857 Scalar::Ptr(ptr) => {
858 trace!("by align({}) ref:", mplace.align.bytes());
859 self.memory.dump_alloc(ptr.alloc_id);
861 ptr => trace!(" integral by ref: {:?}", ptr),
866 pub fn generate_stacktrace(&self, explicit_span: Option<Span>) -> Vec<FrameInfo<'tcx>> {
867 let mut last_span = None;
868 let mut frames = Vec::new();
869 for frame in self.stack().iter().rev() {
870 // make sure we don't emit frames that are duplicates of the previous
871 if explicit_span == Some(frame.span) {
872 last_span = Some(frame.span);
875 if let Some(last) = last_span {
876 if last == frame.span {
880 last_span = Some(frame.span);
883 let lint_root = frame.current_source_info().and_then(|source_info| {
884 match &frame.body.source_scopes[source_info.scope].local_data {
885 mir::ClearCrossCrate::Set(data) => Some(data.lint_root),
886 mir::ClearCrossCrate::Clear => None,
890 frames.push(FrameInfo { call_site: frame.span, instance: frame.instance, lint_root });
892 trace!("generate stacktrace: {:#?}, {:?}", frames, explicit_span);
897 impl<'ctx, 'mir, 'tcx, Tag, Extra> HashStable<StableHashingContext<'ctx>>
898 for Frame<'mir, 'tcx, Tag, Extra>
900 Extra: HashStable<StableHashingContext<'ctx>>,
901 Tag: HashStable<StableHashingContext<'ctx>>,
903 fn hash_stable(&self, hcx: &mut StableHashingContext<'ctx>, hasher: &mut StableHasher) {
904 self.body.hash_stable(hcx, hasher);
905 self.instance.hash_stable(hcx, hasher);
906 self.span.hash_stable(hcx, hasher);
907 self.return_to_block.hash_stable(hcx, hasher);
908 self.return_place.as_ref().map(|r| &**r).hash_stable(hcx, hasher);
909 self.locals.hash_stable(hcx, hasher);
910 self.block.hash_stable(hcx, hasher);
911 self.stmt.hash_stable(hcx, hasher);
912 self.extra.hash_stable(hcx, hasher);