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 => {
156 throw_unsup!(DeadLocal)
158 LocalValue::Live(Operand::Indirect(mplace)) => {
161 ref mut local @ LocalValue::Live(Operand::Immediate(_))
162 | ref mut local @ LocalValue::Uninitialized => {
169 impl<'mir, 'tcx, Tag, Extra> Frame<'mir, 'tcx, Tag, Extra> {
170 /// Return the `SourceInfo` of the current instruction.
171 pub fn current_source_info(&self) -> Option<mir::SourceInfo> {
172 self.block.map(|block| {
173 let block = &self.body.basic_blocks()[block];
174 if self.stmt < block.statements.len() {
175 block.statements[self.stmt].source_info
177 block.terminator().source_info
183 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> HasDataLayout for InterpCx<'mir, 'tcx, M> {
185 fn data_layout(&self) -> &layout::TargetDataLayout {
186 &self.tcx.data_layout
190 impl<'mir, 'tcx, M> layout::HasTyCtxt<'tcx> for InterpCx<'mir, 'tcx, M>
192 M: Machine<'mir, 'tcx>,
195 fn tcx(&self) -> TyCtxt<'tcx> {
200 impl<'mir, 'tcx, M> layout::HasParamEnv<'tcx> for InterpCx<'mir, 'tcx, M>
202 M: Machine<'mir, 'tcx>,
204 fn param_env(&self) -> ty::ParamEnv<'tcx> {
209 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> LayoutOf for InterpCx<'mir, 'tcx, M> {
211 type TyLayout = InterpResult<'tcx, TyLayout<'tcx>>;
214 fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
216 .layout_of(self.param_env.and(ty))
217 .map_err(|layout| err_inval!(Layout(layout)).into())
221 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
224 param_env: ty::ParamEnv<'tcx>,
226 memory_extra: M::MemoryExtra,
232 memory: Memory::new(tcx, memory_extra),
234 vtables: FxHashMap::default(),
241 scalar: Scalar<M::PointerTag>,
242 ) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
243 self.memory.force_ptr(scalar)
249 scalar: Scalar<M::PointerTag>,
251 ) -> InterpResult<'tcx, u128> {
252 self.memory.force_bits(scalar, size)
255 /// Call this to turn untagged "global" pointers (obtained via `tcx`) into
256 /// the *canonical* machine pointer to the allocation. Must never be used
257 /// for any other pointers!
259 /// This represents a *direct* access to that memory, as opposed to access
260 /// through a pointer that was created by the program.
262 pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
263 self.memory.tag_static_base_pointer(ptr)
267 pub fn stack(&self) -> &[Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>] {
272 pub fn cur_frame(&self) -> usize {
273 assert!(self.stack.len() > 0);
278 pub fn frame(&self) -> &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
279 self.stack.last().expect("no call frames exist")
283 pub fn frame_mut(&mut self) -> &mut Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
284 self.stack.last_mut().expect("no call frames exist")
288 pub(super) fn body(&self) -> &'mir mir::Body<'tcx> {
293 pub fn sign_extend(&self, value: u128, ty: TyLayout<'_>) -> u128 {
294 assert!(ty.abi.is_signed());
295 sign_extend(value, ty.size)
299 pub fn truncate(&self, value: u128, ty: TyLayout<'_>) -> u128 {
300 truncate(value, ty.size)
304 pub fn type_is_sized(&self, ty: Ty<'tcx>) -> bool {
305 ty.is_sized(self.tcx, self.param_env)
309 pub fn type_is_freeze(&self, ty: Ty<'tcx>) -> bool {
310 ty.is_freeze(*self.tcx, self.param_env, DUMMY_SP)
315 instance: ty::InstanceDef<'tcx>,
316 promoted: Option<mir::Promoted>,
317 ) -> InterpResult<'tcx, mir::ReadOnlyBodyAndCache<'tcx, 'tcx>> {
318 // do not continue if typeck errors occurred (can only occur in local crate)
319 let did = instance.def_id();
321 && self.tcx.has_typeck_tables(did)
322 && self.tcx.typeck_tables_of(did).tainted_by_errors
324 throw_inval!(TypeckError)
326 trace!("load mir(instance={:?}, promoted={:?})", instance, promoted);
327 if let Some(promoted) = promoted {
328 return Ok(self.tcx.promoted_mir(did)[promoted].unwrap_read_only());
331 ty::InstanceDef::Item(def_id) => {
332 if self.tcx.is_mir_available(did) {
333 Ok(self.tcx.optimized_mir(did).unwrap_read_only())
335 throw_unsup!(NoMirFor(self.tcx.def_path_str(def_id)))
338 _ => Ok(self.tcx.instance_mir(instance)),
342 /// Call this on things you got out of the MIR (so it is as generic as the current
343 /// stack frame), to bring it into the proper environment for this interpreter.
344 pub(super) fn subst_from_frame_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
348 self.tcx.subst_and_normalize_erasing_regions(
349 self.frame().instance.substs,
355 /// The `substs` are assumed to already be in our interpreter "universe" (param_env).
356 pub(super) fn resolve(
359 substs: SubstsRef<'tcx>,
360 ) -> InterpResult<'tcx, ty::Instance<'tcx>> {
361 trace!("resolve: {:?}, {:#?}", def_id, substs);
362 trace!("param_env: {:#?}", self.param_env);
363 trace!("substs: {:#?}", substs);
364 ty::Instance::resolve(*self.tcx, self.param_env, def_id, substs)
365 .ok_or_else(|| err_inval!(TooGeneric).into())
368 pub fn layout_of_local(
370 frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
372 layout: Option<TyLayout<'tcx>>,
373 ) -> InterpResult<'tcx, TyLayout<'tcx>> {
374 // `const_prop` runs into this with an invalid (empty) frame, so we
375 // have to support that case (mostly by skipping all caching).
376 match frame.locals.get(local).and_then(|state| state.layout.get()) {
378 let layout = crate::interpret::operand::from_known_layout(layout, || {
379 let local_ty = frame.body.local_decls[local].ty;
380 let local_ty = self.tcx.subst_and_normalize_erasing_regions(
381 frame.instance.substs,
385 self.layout_of(local_ty)
387 if let Some(state) = frame.locals.get(local) {
388 // Layouts of locals are requested a lot, so we cache them.
389 state.layout.set(Some(layout));
393 Some(layout) => Ok(layout),
397 /// Returns the actual dynamic size and alignment of the place at the given type.
398 /// Only the "meta" (metadata) part of the place matters.
399 /// This can fail to provide an answer for extern types.
400 pub(super) fn size_and_align_of(
402 metadata: MemPlaceMeta<M::PointerTag>,
403 layout: TyLayout<'tcx>,
404 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
405 if !layout.is_unsized() {
406 return Ok(Some((layout.size, layout.align.abi)));
408 match layout.ty.kind {
409 ty::Adt(..) | ty::Tuple(..) => {
410 // First get the size of all statically known fields.
411 // Don't use type_of::sizing_type_of because that expects t to be sized,
412 // and it also rounds up to alignment, which we want to avoid,
413 // as the unsized field's alignment could be smaller.
414 assert!(!layout.ty.is_simd());
415 trace!("DST layout: {:?}", layout);
417 let sized_size = layout.fields.offset(layout.fields.count() - 1);
418 let sized_align = layout.align.abi;
420 "DST {} statically sized prefix size: {:?} align: {:?}",
426 // Recurse to get the size of the dynamically sized field (must be
427 // the last field). Can't have foreign types here, how would we
428 // adjust alignment and size for them?
429 let field = layout.field(self, layout.fields.count() - 1)?;
430 let (unsized_size, unsized_align) = match self.size_and_align_of(metadata, field)? {
431 Some(size_and_align) => size_and_align,
433 // A field with extern type. If this field is at offset 0, we behave
434 // like the underlying extern type.
435 // FIXME: Once we have made decisions for how to handle size and alignment
436 // of `extern type`, this should be adapted. It is just a temporary hack
437 // to get some code to work that probably ought to work.
438 if sized_size == Size::ZERO {
441 bug!("Fields cannot be extern types, unless they are at offset 0")
446 // FIXME (#26403, #27023): We should be adding padding
447 // to `sized_size` (to accommodate the `unsized_align`
448 // required of the unsized field that follows) before
449 // summing it with `sized_size`. (Note that since #26403
450 // is unfixed, we do not yet add the necessary padding
451 // here. But this is where the add would go.)
453 // Return the sum of sizes and max of aligns.
454 let size = sized_size + unsized_size;
456 // Choose max of two known alignments (combined value must
457 // be aligned according to more restrictive of the two).
458 let align = sized_align.max(unsized_align);
460 // Issue #27023: must add any necessary padding to `size`
461 // (to make it a multiple of `align`) before returning it.
462 let size = size.align_to(align);
464 // Check if this brought us over the size limit.
465 if size.bytes() >= self.tcx.data_layout().obj_size_bound() {
467 "wide pointer metadata contains invalid information: \
468 total size is bigger than largest supported object"
471 Ok(Some((size, align)))
474 let vtable = metadata.unwrap_meta();
475 // Read size and align from vtable (already checks size).
476 Ok(Some(self.read_size_and_align_from_vtable(vtable)?))
479 ty::Slice(_) | ty::Str => {
480 let len = metadata.unwrap_meta().to_machine_usize(self)?;
481 let elem = layout.field(self, 0)?;
483 // Make sure the slice is not too big.
484 let size = elem.size.checked_mul(len, &*self.tcx).ok_or_else(|| {
487 total size is bigger than largest supported object"
490 Ok(Some((size, elem.align.abi)))
493 ty::Foreign(_) => Ok(None),
495 _ => bug!("size_and_align_of::<{:?}> not supported", layout.ty),
499 pub fn size_and_align_of_mplace(
501 mplace: MPlaceTy<'tcx, M::PointerTag>,
502 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
503 self.size_and_align_of(mplace.meta, mplace.layout)
506 pub fn push_stack_frame(
508 instance: ty::Instance<'tcx>,
510 body: &'mir mir::Body<'tcx>,
511 return_place: Option<PlaceTy<'tcx, M::PointerTag>>,
512 return_to_block: StackPopCleanup,
513 ) -> InterpResult<'tcx> {
514 if self.stack.len() > 0 {
515 info!("PAUSING({}) {}", self.cur_frame(), self.frame().instance);
517 ::log_settings::settings().indentation += 1;
519 // first push a stack frame so we have access to the local substs
520 let extra = M::stack_push(self)?;
521 self.stack.push(Frame {
523 block: Some(mir::START_BLOCK),
526 // empty local array, we fill it in below, after we are inside the stack frame and
527 // all methods actually know about the frame
528 locals: IndexVec::new(),
535 // don't allocate at all for trivial constants
536 if body.local_decls.len() > 1 {
537 // Locals are initially uninitialized.
538 let dummy = LocalState { value: LocalValue::Uninitialized, layout: Cell::new(None) };
539 let mut locals = IndexVec::from_elem(dummy, &body.local_decls);
540 // Return place is handled specially by the `eval_place` functions, and the
541 // entry in `locals` should never be used. Make it dead, to be sure.
542 locals[mir::RETURN_PLACE].value = LocalValue::Dead;
543 // Now mark those locals as dead that we do not want to initialize
544 match self.tcx.def_kind(instance.def_id()) {
545 // statics and constants don't have `Storage*` statements, no need to look for them
546 Some(DefKind::Static) | Some(DefKind::Const) | Some(DefKind::AssocConst) => {}
548 trace!("push_stack_frame: {:?}: num_bbs: {}", span, body.basic_blocks().len());
549 for block in body.basic_blocks() {
550 for stmt in block.statements.iter() {
551 use rustc::mir::StatementKind::{StorageDead, StorageLive};
553 StorageLive(local) | StorageDead(local) => {
554 locals[local].value = LocalValue::Dead;
563 self.frame_mut().locals = locals;
566 info!("ENTERING({}) {}", self.cur_frame(), self.frame().instance);
568 if self.stack.len() > *self.tcx.sess.recursion_limit.get() {
569 throw_exhaust!(StackFrameLimitReached)
575 /// Jump to the given block.
577 pub fn go_to_block(&mut self, target: mir::BasicBlock) {
578 let frame = self.frame_mut();
579 frame.block = Some(target);
583 /// *Return* to the given `target` basic block.
584 /// Do *not* use for unwinding! Use `unwind_to_block` instead.
586 /// If `target` is `None`, that indicates the function cannot return, so we raise UB.
587 pub fn return_to_block(&mut self, target: Option<mir::BasicBlock>) -> InterpResult<'tcx> {
588 if let Some(target) = target {
589 Ok(self.go_to_block(target))
591 throw_ub!(Unreachable)
595 /// *Unwind* to the given `target` basic block.
596 /// Do *not* use for returning! Use `return_to_block` instead.
598 /// If `target` is `None`, that indicates the function does not need cleanup during
599 /// unwinding, and we will just keep propagating that upwards.
600 pub fn unwind_to_block(&mut self, target: Option<mir::BasicBlock>) {
601 let frame = self.frame_mut();
602 frame.block = target;
606 /// Pops the current frame from the stack, deallocating the
607 /// memory for allocated locals.
609 /// If `unwinding` is `false`, then we are performing a normal return
610 /// from a function. In this case, we jump back into the frame of the caller,
611 /// and continue execution as normal.
613 /// If `unwinding` is `true`, then we are in the middle of a panic,
614 /// and need to unwind this frame. In this case, we jump to the
615 /// `cleanup` block for the function, which is responsible for running
616 /// `Drop` impls for any locals that have been initialized at this point.
617 /// The cleanup block ends with a special `Resume` terminator, which will
618 /// cause us to continue unwinding.
619 pub(super) fn pop_stack_frame(&mut self, unwinding: bool) -> InterpResult<'tcx> {
621 "LEAVING({}) {} (unwinding = {})",
623 self.frame().instance,
627 // Sanity check `unwinding`.
630 match self.frame().block {
632 Some(block) => self.body().basic_blocks()[block].is_cleanup,
636 ::log_settings::settings().indentation -= 1;
637 let frame = self.stack.pop().expect("tried to pop a stack frame, but there were none");
638 let stack_pop_info = M::stack_pop(self, frame.extra, unwinding)?;
639 if let (false, StackPopInfo::StopUnwinding) = (unwinding, stack_pop_info) {
640 bug!("Attempted to stop unwinding while there is no unwinding!");
643 // Now where do we jump next?
645 // Determine if we leave this function normally or via unwinding.
647 if let StackPopInfo::StopUnwinding = stack_pop_info { false } else { unwinding };
649 // Usually we want to clean up (deallocate locals), but in a few rare cases we don't.
650 // In that case, we return early. We also avoid validation in that case,
651 // because this is CTFE and the final value will be thoroughly validated anyway.
652 let (cleanup, next_block) = match frame.return_to_block {
653 StackPopCleanup::Goto { ret, unwind } => {
654 (true, Some(if cur_unwinding { unwind } else { ret }))
656 StackPopCleanup::None { cleanup, .. } => (cleanup, None),
660 assert!(self.stack.is_empty(), "only the topmost frame should ever be leaked");
661 assert!(next_block.is_none(), "tried to skip cleanup when we have a next block!");
662 // Leak the locals, skip validation.
666 // Cleanup: deallocate all locals that are backed by an allocation.
667 for local in frame.locals {
668 self.deallocate_local(local.value)?;
672 "StackPopCleanup: {:?} StackPopInfo: {:?} cur_unwinding = {:?}",
673 frame.return_to_block,
678 // Follow the unwind edge.
679 let unwind = next_block.expect("Encounted StackPopCleanup::None when unwinding!");
680 self.unwind_to_block(unwind);
682 // Follow the normal return edge.
683 // Validate the return value. Do this after deallocating so that we catch dangling
685 if let Some(return_place) = frame.return_place {
686 if M::enforce_validity(self) {
687 // Data got changed, better make sure it matches the type!
688 // It is still possible that the return place held invalid data while
689 // the function is running, but that's okay because nobody could have
690 // accessed that same data from the "outside" to observe any broken
691 // invariant -- that is, unless a function somehow has a ptr to
692 // its return place... but the way MIR is currently generated, the
693 // return place is always a local and then this cannot happen.
694 self.validate_operand(self.place_to_op(return_place)?, vec![], None)?;
697 // Uh, that shouldn't happen... the function did not intend to return
698 throw_ub!(Unreachable);
701 // Jump to new block -- *after* validation so that the spans make more sense.
702 if let Some(ret) = next_block {
703 self.return_to_block(ret)?;
707 if self.stack.len() > 0 {
709 "CONTINUING({}) {} (unwinding = {})",
711 self.frame().instance,
719 /// Mark a storage as live, killing the previous content and returning it.
720 /// Remember to deallocate that!
724 ) -> InterpResult<'tcx, LocalValue<M::PointerTag>> {
725 assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
726 trace!("{:?} is now live", local);
728 let local_val = LocalValue::Uninitialized;
729 // StorageLive *always* kills the value that's currently stored.
730 // However, we do not error if the variable already is live;
731 // see <https://github.com/rust-lang/rust/issues/42371>.
732 Ok(mem::replace(&mut self.frame_mut().locals[local].value, local_val))
735 /// Returns the old value of the local.
736 /// Remember to deallocate that!
737 pub fn storage_dead(&mut self, local: mir::Local) -> LocalValue<M::PointerTag> {
738 assert!(local != mir::RETURN_PLACE, "Cannot make return place dead");
739 trace!("{:?} is now dead", local);
741 mem::replace(&mut self.frame_mut().locals[local].value, LocalValue::Dead)
744 pub(super) fn deallocate_local(
746 local: LocalValue<M::PointerTag>,
747 ) -> InterpResult<'tcx> {
748 // FIXME: should we tell the user that there was a local which was never written to?
749 if let LocalValue::Live(Operand::Indirect(MemPlace { ptr, .. })) = local {
750 trace!("deallocating local");
751 // All locals have a backing allocation, even if the allocation is empty
752 // due to the local having ZST type.
753 let ptr = ptr.assert_ptr();
754 if log_enabled!(::log::Level::Trace) {
755 self.memory.dump_alloc(ptr.alloc_id);
757 self.memory.deallocate_local(ptr)?;
762 pub(super) fn const_eval(
765 ) -> InterpResult<'tcx, OpTy<'tcx, M::PointerTag>> {
766 // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
767 // and thus don't care about the parameter environment. While we could just use
768 // `self.param_env`, that would mean we invoke the query to evaluate the static
769 // with different parameter environments, thus causing the static to be evaluated
771 let param_env = if self.tcx.is_static(gid.instance.def_id()) {
772 ty::ParamEnv::reveal_all()
776 let val = if let Some(promoted) = gid.promoted {
777 self.tcx.const_eval_promoted(param_env, gid.instance, promoted)?
779 self.tcx.const_eval_instance(param_env, gid.instance, Some(self.tcx.span))?
782 // Even though `ecx.const_eval` is called from `eval_const_to_op` we can never have a
783 // recursion deeper than one level, because the `tcx.const_eval` above is guaranteed to not
784 // return `ConstValue::Unevaluated`, which is the only way that `eval_const_to_op` will call
786 self.eval_const_to_op(val, None)
789 pub fn const_eval_raw(
792 ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
793 // For statics we pick `ParamEnv::reveal_all`, because statics don't have generics
794 // and thus don't care about the parameter environment. While we could just use
795 // `self.param_env`, that would mean we invoke the query to evaluate the static
796 // with different parameter environments, thus causing the static to be evaluated
798 let param_env = if self.tcx.is_static(gid.instance.def_id()) {
799 ty::ParamEnv::reveal_all()
803 // We use `const_eval_raw` here, and get an unvalidated result. That is okay:
804 // Our result will later be validated anyway, and there seems no good reason
805 // to have to fail early here. This is also more consistent with
806 // `Memory::get_static_alloc` which has to use `const_eval_raw` to avoid cycles.
807 let val = self.tcx.const_eval_raw(param_env.and(gid))?;
808 self.raw_const_to_mplace(val)
811 pub fn dump_place(&self, place: Place<M::PointerTag>) {
813 if !log_enabled!(::log::Level::Trace) {
817 Place::Local { frame, local } => {
818 let mut allocs = Vec::new();
819 let mut msg = format!("{:?}", local);
820 if frame != self.cur_frame() {
821 write!(msg, " ({} frames up)", self.cur_frame() - frame).unwrap();
823 write!(msg, ":").unwrap();
825 match self.stack[frame].locals[local].value {
826 LocalValue::Dead => write!(msg, " is dead").unwrap(),
827 LocalValue::Uninitialized => write!(msg, " is uninitialized").unwrap(),
828 LocalValue::Live(Operand::Indirect(mplace)) => match mplace.ptr {
829 Scalar::Ptr(ptr) => {
832 " by align({}){} ref:",
833 mplace.align.bytes(),
835 MemPlaceMeta::Meta(meta) => format!(" meta({:?})", meta),
836 MemPlaceMeta::Poison | MemPlaceMeta::None => String::new(),
840 allocs.push(ptr.alloc_id);
842 ptr => write!(msg, " by integral ref: {:?}", ptr).unwrap(),
844 LocalValue::Live(Operand::Immediate(Immediate::Scalar(val))) => {
845 write!(msg, " {:?}", val).unwrap();
846 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val {
847 allocs.push(ptr.alloc_id);
850 LocalValue::Live(Operand::Immediate(Immediate::ScalarPair(val1, val2))) => {
851 write!(msg, " ({:?}, {:?})", val1, val2).unwrap();
852 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val1 {
853 allocs.push(ptr.alloc_id);
855 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val2 {
856 allocs.push(ptr.alloc_id);
862 self.memory.dump_allocs(allocs);
864 Place::Ptr(mplace) => match mplace.ptr {
865 Scalar::Ptr(ptr) => {
866 trace!("by align({}) ref:", mplace.align.bytes());
867 self.memory.dump_alloc(ptr.alloc_id);
869 ptr => trace!(" integral by ref: {:?}", ptr),
874 pub fn generate_stacktrace(&self, explicit_span: Option<Span>) -> Vec<FrameInfo<'tcx>> {
875 let mut last_span = None;
876 let mut frames = Vec::new();
877 for frame in self.stack().iter().rev() {
878 // make sure we don't emit frames that are duplicates of the previous
879 if explicit_span == Some(frame.span) {
880 last_span = Some(frame.span);
883 if let Some(last) = last_span {
884 if last == frame.span {
888 last_span = Some(frame.span);
891 let lint_root = frame.current_source_info().and_then(|source_info| {
892 match &frame.body.source_scopes[source_info.scope].local_data {
893 mir::ClearCrossCrate::Set(data) => Some(data.lint_root),
894 mir::ClearCrossCrate::Clear => None,
898 frames.push(FrameInfo { call_site: frame.span, instance: frame.instance, lint_root });
900 trace!("generate stacktrace: {:#?}, {:?}", frames, explicit_span);
905 impl<'ctx, 'mir, 'tcx, Tag, Extra> HashStable<StableHashingContext<'ctx>>
906 for Frame<'mir, 'tcx, Tag, Extra>
908 Extra: HashStable<StableHashingContext<'ctx>>,
909 Tag: HashStable<StableHashingContext<'ctx>>,
911 fn hash_stable(&self, hcx: &mut StableHashingContext<'ctx>, hasher: &mut StableHasher) {
912 self.body.hash_stable(hcx, hasher);
913 self.instance.hash_stable(hcx, hasher);
914 self.span.hash_stable(hcx, hasher);
915 self.return_to_block.hash_stable(hcx, hasher);
916 self.return_place.as_ref().map(|r| &**r).hash_stable(hcx, hasher);
917 self.locals.hash_stable(hcx, hasher);
918 self.block.hash_stable(hcx, hasher);
919 self.stmt.hash_stable(hcx, hasher);
920 self.extra.hash_stable(hcx, hasher);