5 use syntax::source_map::{self, Span, DUMMY_SP};
6 use rustc::hir::def_id::DefId;
7 use rustc::hir::def::DefKind;
9 use rustc::ty::layout::{
10 self, Size, Align, HasDataLayout, LayoutOf, TyLayout
12 use rustc::ty::subst::{Subst, SubstsRef};
13 use rustc::ty::{self, Ty, TyCtxt, TypeFoldable};
14 use rustc::ty::query::TyCtxtAt;
15 use rustc_data_structures::indexed_vec::IndexVec;
16 use rustc::mir::interpret::{
18 GlobalId, Scalar, Pointer, FrameInfo, AllocId,
19 InterpResult, InterpError,
20 truncate, sign_extend, InvalidProgramInfo,
22 use rustc_data_structures::fx::FxHashMap;
25 Immediate, Operand, MemPlace, MPlaceTy, Place, PlaceTy, ScalarMaybeUndef,
29 pub struct InterpCx<'mir, 'tcx, M: Machine<'mir, 'tcx>> {
30 /// Stores the `Machine` instance.
33 /// The results of the type checker, from rustc.
34 pub tcx: TyCtxtAt<'tcx>,
36 /// Bounds in scope for polymorphic evaluations.
37 pub(crate) param_env: ty::ParamEnv<'tcx>,
39 /// The virtual memory system.
40 pub(crate) memory: Memory<'mir, 'tcx, M>,
42 /// The virtual call stack.
43 pub(crate) stack: Vec<Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>>,
45 /// A cache for deduplicating vtables
47 FxHashMap<(Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>), Pointer<M::PointerTag>>,
52 pub struct Frame<'mir, 'tcx, Tag=(), Extra=()> {
53 ////////////////////////////////////////////////////////////////////////////////
54 // Function and callsite information
55 ////////////////////////////////////////////////////////////////////////////////
56 /// The MIR for the function called on this frame.
57 pub body: &'mir mir::Body<'tcx>,
59 /// The def_id and substs of the current function.
60 pub instance: ty::Instance<'tcx>,
62 /// The span of the call site.
63 pub span: source_map::Span,
65 ////////////////////////////////////////////////////////////////////////////////
66 // Return place and locals
67 ////////////////////////////////////////////////////////////////////////////////
68 /// Work to perform when returning from this function.
69 pub return_to_block: StackPopCleanup,
71 /// The location where the result of the current stack frame should be written to,
72 /// and its layout in the caller.
73 pub return_place: Option<PlaceTy<'tcx, Tag>>,
75 /// The list of locals for this stack frame, stored in order as
76 /// `[return_ptr, arguments..., variables..., temporaries...]`.
77 /// The locals are stored as `Option<Value>`s.
78 /// `None` represents a local that is currently dead, while a live local
79 /// can either directly contain `Scalar` or refer to some part of an `Allocation`.
80 pub locals: IndexVec<mir::Local, LocalState<'tcx, Tag>>,
82 ////////////////////////////////////////////////////////////////////////////////
83 // Current position within the function
84 ////////////////////////////////////////////////////////////////////////////////
85 /// The block that is currently executed (or will be executed after the above call stacks
87 pub block: mir::BasicBlock,
89 /// The index of the currently evaluated statement.
92 /// Extra data for the machine.
96 #[derive(Clone, Debug, Eq, PartialEq, Hash)]
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 Goto(Option<mir::BasicBlock>),
102 /// Just do nohing: Used by Main and for the box_alloc hook in miri.
103 /// `cleanup` says whether locals are deallocated. Static computation
104 /// wants them leaked to intern what they need (and just throw away
105 /// the entire `ecx` when it is done).
106 None { cleanup: bool },
109 /// State of a local variable including a memoized layout
110 #[derive(Clone, PartialEq, Eq)]
111 pub struct LocalState<'tcx, Tag=(), Id=AllocId> {
112 pub value: LocalValue<Tag, Id>,
113 /// Don't modify if `Some`, this is only used to prevent computing the layout twice
114 pub layout: Cell<Option<TyLayout<'tcx>>>,
117 /// Current value of a local variable
118 #[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
119 pub enum LocalValue<Tag=(), Id=AllocId> {
120 /// This local is not currently alive, and cannot be used at all.
122 /// This local is alive but not yet initialized. It can be written to
123 /// but not read from or its address taken. Locals get initialized on
124 /// first write because for unsized locals, we do not know their size
127 /// A normal, live local.
128 /// Mostly for convenience, we re-use the `Operand` type here.
129 /// This is an optimization over just always having a pointer here;
130 /// we can thus avoid doing an allocation when the local just stores
131 /// immediate values *and* never has its address taken.
132 Live(Operand<Tag, Id>),
135 impl<'tcx, Tag: Copy + 'static> LocalState<'tcx, Tag> {
136 pub fn access(&self) -> InterpResult<'tcx, Operand<Tag>> {
138 LocalValue::Dead => err!(DeadLocal),
139 LocalValue::Uninitialized =>
140 bug!("The type checker should prevent reading from a never-written local"),
141 LocalValue::Live(val) => Ok(val),
145 /// Overwrite the local. If the local can be overwritten in place, return a reference
146 /// to do so; otherwise return the `MemPlace` to consult instead.
149 ) -> InterpResult<'tcx, Result<&mut LocalValue<Tag>, MemPlace<Tag>>> {
151 LocalValue::Dead => err!(DeadLocal),
152 LocalValue::Live(Operand::Indirect(mplace)) => Ok(Err(mplace)),
153 ref mut local @ LocalValue::Live(Operand::Immediate(_)) |
154 ref mut local @ LocalValue::Uninitialized => {
161 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> HasDataLayout for InterpCx<'mir, 'tcx, M> {
163 fn data_layout(&self) -> &layout::TargetDataLayout {
164 &self.tcx.data_layout
168 impl<'mir, 'tcx, M> layout::HasTyCtxt<'tcx> for InterpCx<'mir, 'tcx, M>
170 M: Machine<'mir, 'tcx>,
173 fn tcx(&self) -> TyCtxt<'tcx> {
178 impl<'mir, 'tcx, M> layout::HasParamEnv<'tcx> for InterpCx<'mir, 'tcx, M>
180 M: Machine<'mir, 'tcx>,
182 fn param_env(&self) -> ty::ParamEnv<'tcx> {
187 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> LayoutOf for InterpCx<'mir, 'tcx, M> {
189 type TyLayout = InterpResult<'tcx, TyLayout<'tcx>>;
192 fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
194 .layout_of(self.param_env.and(ty))
196 InterpError::InvalidProgram(InvalidProgramInfo::Layout(layout)).into()
201 impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
204 param_env: ty::ParamEnv<'tcx>,
206 memory_extra: M::MemoryExtra,
212 memory: Memory::new(tcx, memory_extra),
214 vtables: FxHashMap::default(),
219 pub fn memory(&self) -> &Memory<'mir, 'tcx, M> {
224 pub fn memory_mut(&mut self) -> &mut Memory<'mir, 'tcx, M> {
231 scalar: Scalar<M::PointerTag>,
232 ) -> InterpResult<'tcx, Pointer<M::PointerTag>> {
233 self.memory.force_ptr(scalar)
239 scalar: Scalar<M::PointerTag>,
241 ) -> InterpResult<'tcx, u128> {
242 self.memory.force_bits(scalar, size)
246 pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> {
247 self.memory.tag_static_base_pointer(ptr)
251 pub fn stack(&self) -> &[Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>] {
256 pub fn cur_frame(&self) -> usize {
257 assert!(self.stack.len() > 0);
262 pub fn frame(&self) -> &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
263 self.stack.last().expect("no call frames exist")
267 pub fn frame_mut(&mut self) -> &mut Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra> {
268 self.stack.last_mut().expect("no call frames exist")
272 pub(super) fn body(&self) -> &'mir mir::Body<'tcx> {
277 pub fn sign_extend(&self, value: u128, ty: TyLayout<'_>) -> u128 {
278 assert!(ty.abi.is_signed());
279 sign_extend(value, ty.size)
283 pub fn truncate(&self, value: u128, ty: TyLayout<'_>) -> u128 {
284 truncate(value, ty.size)
288 pub fn type_is_sized(&self, ty: Ty<'tcx>) -> bool {
289 ty.is_sized(self.tcx, self.param_env)
293 pub fn type_is_freeze(&self, ty: Ty<'tcx>) -> bool {
294 ty.is_freeze(*self.tcx, self.param_env, DUMMY_SP)
297 pub(super) fn subst_and_normalize_erasing_regions<T: TypeFoldable<'tcx>>(
300 ) -> InterpResult<'tcx, T> {
301 match self.stack.last() {
302 Some(frame) => Ok(self.tcx.subst_and_normalize_erasing_regions(
303 frame.instance.substs,
307 None => if substs.needs_subst() {
308 err_inval!(TooGeneric)
315 pub(super) fn resolve(
318 substs: SubstsRef<'tcx>
319 ) -> InterpResult<'tcx, ty::Instance<'tcx>> {
320 trace!("resolve: {:?}, {:#?}", def_id, substs);
321 trace!("param_env: {:#?}", self.param_env);
322 let substs = self.subst_and_normalize_erasing_regions(substs)?;
323 trace!("substs: {:#?}", substs);
324 ty::Instance::resolve(
329 ).ok_or_else(|| inval!(TooGeneric).into())
334 instance: ty::InstanceDef<'tcx>,
335 ) -> InterpResult<'tcx, &'tcx mir::Body<'tcx>> {
336 // do not continue if typeck errors occurred (can only occur in local crate)
337 let did = instance.def_id();
339 && self.tcx.has_typeck_tables(did)
340 && self.tcx.typeck_tables_of(did).tainted_by_errors
342 return err_inval!(TypeckError);
344 trace!("load mir {:?}", instance);
346 ty::InstanceDef::Item(def_id) => if self.tcx.is_mir_available(did) {
347 Ok(self.tcx.optimized_mir(did))
349 err!(NoMirFor(self.tcx.def_path_str(def_id)))
351 _ => Ok(self.tcx.instance_mir(instance)),
355 pub(super) fn monomorphize<T: TypeFoldable<'tcx> + Subst<'tcx>>(
358 ) -> InterpResult<'tcx, T> {
359 match self.stack.last() {
360 Some(frame) => Ok(self.monomorphize_with_substs(t, frame.instance.substs)?),
361 None => if t.needs_subst() {
362 err_inval!(TooGeneric).into()
369 fn monomorphize_with_substs<T: TypeFoldable<'tcx> + Subst<'tcx>>(
372 substs: SubstsRef<'tcx>
373 ) -> InterpResult<'tcx, T> {
374 // miri doesn't care about lifetimes, and will choke on some crazy ones
375 // let's simply get rid of them
376 let substituted = t.subst(*self.tcx, substs);
378 if substituted.needs_subst() {
379 return err_inval!(TooGeneric);
382 Ok(self.tcx.normalize_erasing_regions(ty::ParamEnv::reveal_all(), substituted))
385 pub fn layout_of_local(
387 frame: &Frame<'mir, 'tcx, M::PointerTag, M::FrameExtra>,
389 layout: Option<TyLayout<'tcx>>,
390 ) -> InterpResult<'tcx, TyLayout<'tcx>> {
391 match frame.locals[local].layout.get() {
393 let layout = crate::interpret::operand::from_known_layout(layout, || {
394 let local_ty = frame.body.local_decls[local].ty;
395 let local_ty = self.monomorphize_with_substs(local_ty, frame.instance.substs)?;
396 self.layout_of(local_ty)
398 // Layouts of locals are requested a lot, so we cache them.
399 frame.locals[local].layout.set(Some(layout));
402 Some(layout) => Ok(layout),
406 /// Returns the actual dynamic size and alignment of the place at the given type.
407 /// Only the "meta" (metadata) part of the place matters.
408 /// This can fail to provide an answer for extern types.
409 pub(super) fn size_and_align_of(
411 metadata: Option<Scalar<M::PointerTag>>,
412 layout: TyLayout<'tcx>,
413 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
414 if !layout.is_unsized() {
415 return Ok(Some((layout.size, layout.align.abi)));
417 match layout.ty.sty {
418 ty::Adt(..) | ty::Tuple(..) => {
419 // First get the size of all statically known fields.
420 // Don't use type_of::sizing_type_of because that expects t to be sized,
421 // and it also rounds up to alignment, which we want to avoid,
422 // as the unsized field's alignment could be smaller.
423 assert!(!layout.ty.is_simd());
424 trace!("DST layout: {:?}", layout);
426 let sized_size = layout.fields.offset(layout.fields.count() - 1);
427 let sized_align = layout.align.abi;
429 "DST {} statically sized prefix size: {:?} align: {:?}",
435 // Recurse to get the size of the dynamically sized field (must be
436 // the last field). Can't have foreign types here, how would we
437 // adjust alignment and size for them?
438 let field = layout.field(self, layout.fields.count() - 1)?;
439 let (unsized_size, unsized_align) = match self.size_and_align_of(metadata, field)? {
440 Some(size_and_align) => size_and_align,
442 // A field with extern type. If this field is at offset 0, we behave
443 // like the underlying extern type.
444 // FIXME: Once we have made decisions for how to handle size and alignment
445 // of `extern type`, this should be adapted. It is just a temporary hack
446 // to get some code to work that probably ought to work.
447 if sized_size == Size::ZERO {
450 bug!("Fields cannot be extern types, unless they are at offset 0")
455 // FIXME (#26403, #27023): We should be adding padding
456 // to `sized_size` (to accommodate the `unsized_align`
457 // required of the unsized field that follows) before
458 // summing it with `sized_size`. (Note that since #26403
459 // is unfixed, we do not yet add the necessary padding
460 // here. But this is where the add would go.)
462 // Return the sum of sizes and max of aligns.
463 let size = sized_size + unsized_size;
465 // Choose max of two known alignments (combined value must
466 // be aligned according to more restrictive of the two).
467 let align = sized_align.max(unsized_align);
469 // Issue #27023: must add any necessary padding to `size`
470 // (to make it a multiple of `align`) before returning it.
472 // Namely, the returned size should be, in C notation:
474 // `size + ((size & (align-1)) ? align : 0)`
476 // emulated via the semi-standard fast bit trick:
478 // `(size + (align-1)) & -align`
480 Ok(Some((size.align_to(align), align)))
483 let vtable = metadata.expect("dyn trait fat ptr must have vtable");
484 // the second entry in the vtable is the dynamic size of the object.
485 Ok(Some(self.read_size_and_align_from_vtable(vtable)?))
488 ty::Slice(_) | ty::Str => {
489 let len = metadata.expect("slice fat ptr must have vtable").to_usize(self)?;
490 let elem = layout.field(self, 0)?;
491 Ok(Some((elem.size * len, elem.align.abi)))
498 _ => bug!("size_and_align_of::<{:?}> not supported", layout.ty),
502 pub fn size_and_align_of_mplace(
504 mplace: MPlaceTy<'tcx, M::PointerTag>
505 ) -> InterpResult<'tcx, Option<(Size, Align)>> {
506 self.size_and_align_of(mplace.meta, mplace.layout)
509 pub fn push_stack_frame(
511 instance: ty::Instance<'tcx>,
512 span: source_map::Span,
513 body: &'mir mir::Body<'tcx>,
514 return_place: Option<PlaceTy<'tcx, M::PointerTag>>,
515 return_to_block: StackPopCleanup,
516 ) -> InterpResult<'tcx> {
517 if self.stack.len() > 0 {
518 info!("PAUSING({}) {}", self.cur_frame(), self.frame().instance);
520 ::log_settings::settings().indentation += 1;
522 // first push a stack frame so we have access to the local substs
523 let extra = M::stack_push(self)?;
524 self.stack.push(Frame {
526 block: mir::START_BLOCK,
529 // empty local array, we fill it in below, after we are inside the stack frame and
530 // all methods actually know about the frame
531 locals: IndexVec::new(),
538 // don't allocate at all for trivial constants
539 if body.local_decls.len() > 1 {
540 // Locals are initially uninitialized.
541 let dummy = LocalState {
542 value: LocalValue::Uninitialized,
543 layout: Cell::new(None),
545 let mut locals = IndexVec::from_elem(dummy, &body.local_decls);
546 // Return place is handled specially by the `eval_place` functions, and the
547 // entry in `locals` should never be used. Make it dead, to be sure.
548 locals[mir::RETURN_PLACE].value = LocalValue::Dead;
549 // Now mark those locals as dead that we do not want to initialize
550 match self.tcx.def_kind(instance.def_id()) {
551 // statics and constants don't have `Storage*` statements, no need to look for them
552 Some(DefKind::Static)
553 | Some(DefKind::Const)
554 | Some(DefKind::AssocConst) => {},
556 trace!("push_stack_frame: {:?}: num_bbs: {}", span, body.basic_blocks().len());
557 for block in body.basic_blocks() {
558 for stmt in block.statements.iter() {
559 use rustc::mir::StatementKind::{StorageDead, StorageLive};
562 StorageDead(local) => {
563 locals[local].value = LocalValue::Dead;
572 self.frame_mut().locals = locals;
575 info!("ENTERING({}) {}", self.cur_frame(), self.frame().instance);
577 if self.stack.len() > self.tcx.sess.const_eval_stack_frame_limit {
578 err_exhaust!(StackFrameLimitReached)
584 pub(super) fn pop_stack_frame(&mut self) -> InterpResult<'tcx> {
585 info!("LEAVING({}) {}", self.cur_frame(), self.frame().instance);
586 ::log_settings::settings().indentation -= 1;
587 let frame = self.stack.pop().expect(
588 "tried to pop a stack frame, but there were none",
590 M::stack_pop(self, frame.extra)?;
591 // Abort early if we do not want to clean up: We also avoid validation in that case,
592 // because this is CTFE and the final value will be thoroughly validated anyway.
593 match frame.return_to_block {
594 StackPopCleanup::Goto(_) => {},
595 StackPopCleanup::None { cleanup } => {
597 assert!(self.stack.is_empty(), "only the topmost frame should ever be leaked");
598 // Leak the locals, skip validation.
603 // Deallocate all locals that are backed by an allocation.
604 for local in frame.locals {
605 self.deallocate_local(local.value)?;
607 // Validate the return value. Do this after deallocating so that we catch dangling
609 if let Some(return_place) = frame.return_place {
610 if M::enforce_validity(self) {
611 // Data got changed, better make sure it matches the type!
612 // It is still possible that the return place held invalid data while
613 // the function is running, but that's okay because nobody could have
614 // accessed that same data from the "outside" to observe any broken
615 // invariant -- that is, unless a function somehow has a ptr to
616 // its return place... but the way MIR is currently generated, the
617 // return place is always a local and then this cannot happen.
618 self.validate_operand(
619 self.place_to_op(return_place)?,
625 // Uh, that shouldn't happen... the function did not intend to return
626 return err_ub!(Unreachable);
628 // Jump to new block -- *after* validation so that the spans make more sense.
629 match frame.return_to_block {
630 StackPopCleanup::Goto(block) => {
631 self.goto_block(block)?;
633 StackPopCleanup::None { .. } => {}
636 if self.stack.len() > 0 {
637 info!("CONTINUING({}) {}", self.cur_frame(), self.frame().instance);
643 /// Mark a storage as live, killing the previous content and returning it.
644 /// Remember to deallocate that!
648 ) -> InterpResult<'tcx, LocalValue<M::PointerTag>> {
649 assert!(local != mir::RETURN_PLACE, "Cannot make return place live");
650 trace!("{:?} is now live", local);
652 let local_val = LocalValue::Uninitialized;
653 // StorageLive *always* kills the value that's currently stored.
654 // However, we do not error if the variable already is live;
655 // see <https://github.com/rust-lang/rust/issues/42371>.
656 Ok(mem::replace(&mut self.frame_mut().locals[local].value, local_val))
659 /// Returns the old value of the local.
660 /// Remember to deallocate that!
661 pub fn storage_dead(&mut self, local: mir::Local) -> LocalValue<M::PointerTag> {
662 assert!(local != mir::RETURN_PLACE, "Cannot make return place dead");
663 trace!("{:?} is now dead", local);
665 mem::replace(&mut self.frame_mut().locals[local].value, LocalValue::Dead)
668 pub(super) fn deallocate_local(
670 local: LocalValue<M::PointerTag>,
671 ) -> InterpResult<'tcx> {
672 // FIXME: should we tell the user that there was a local which was never written to?
673 if let LocalValue::Live(Operand::Indirect(MemPlace { ptr, .. })) = local {
674 trace!("deallocating local");
675 let ptr = ptr.to_ptr()?;
676 self.memory.dump_alloc(ptr.alloc_id);
677 self.memory.deallocate_local(ptr)?;
682 pub fn const_eval_raw(
685 ) -> InterpResult<'tcx, MPlaceTy<'tcx, M::PointerTag>> {
686 // FIXME(oli-obk): make this check an assertion that it's not a static here
687 // FIXME(RalfJ, oli-obk): document that `Place::Static` can never be anything but a static
688 // and `ConstValue::Unevaluated` can never be a static
689 let param_env = if self.tcx.is_static(gid.instance.def_id()) {
690 ty::ParamEnv::reveal_all()
694 // We use `const_eval_raw` here, and get an unvalidated result. That is okay:
695 // Our result will later be validated anyway, and there seems no good reason
696 // to have to fail early here. This is also more consistent with
697 // `Memory::get_static_alloc` which has to use `const_eval_raw` to avoid cycles.
698 let val = self.tcx.const_eval_raw(param_env.and(gid)).map_err(|err| {
700 ErrorHandled::Reported =>
701 InterpError::InvalidProgram(InvalidProgramInfo::ReferencedConstant),
702 ErrorHandled::TooGeneric =>
703 InterpError::InvalidProgram(InvalidProgramInfo::TooGeneric),
706 self.raw_const_to_mplace(val)
709 pub fn dump_place(&self, place: Place<M::PointerTag>) {
711 if !log_enabled!(::log::Level::Trace) {
715 Place::Local { frame, local } => {
716 let mut allocs = Vec::new();
717 let mut msg = format!("{:?}", local);
718 if frame != self.cur_frame() {
719 write!(msg, " ({} frames up)", self.cur_frame() - frame).unwrap();
721 write!(msg, ":").unwrap();
723 match self.stack[frame].locals[local].value {
724 LocalValue::Dead => write!(msg, " is dead").unwrap(),
725 LocalValue::Uninitialized => write!(msg, " is uninitialized").unwrap(),
726 LocalValue::Live(Operand::Indirect(mplace)) => {
728 Scalar::Ptr(ptr) => {
729 write!(msg, " by align({}){} ref:",
730 mplace.align.bytes(),
732 Some(meta) => format!(" meta({:?})", meta),
733 None => String::new()
736 allocs.push(ptr.alloc_id);
738 ptr => write!(msg, " by integral ref: {:?}", ptr).unwrap(),
741 LocalValue::Live(Operand::Immediate(Immediate::Scalar(val))) => {
742 write!(msg, " {:?}", val).unwrap();
743 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val {
744 allocs.push(ptr.alloc_id);
747 LocalValue::Live(Operand::Immediate(Immediate::ScalarPair(val1, val2))) => {
748 write!(msg, " ({:?}, {:?})", val1, val2).unwrap();
749 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val1 {
750 allocs.push(ptr.alloc_id);
752 if let ScalarMaybeUndef::Scalar(Scalar::Ptr(ptr)) = val2 {
753 allocs.push(ptr.alloc_id);
759 self.memory.dump_allocs(allocs);
761 Place::Ptr(mplace) => {
763 Scalar::Ptr(ptr) => {
764 trace!("by align({}) ref:", mplace.align.bytes());
765 self.memory.dump_alloc(ptr.alloc_id);
767 ptr => trace!(" integral by ref: {:?}", ptr),
773 pub fn generate_stacktrace(&self, explicit_span: Option<Span>) -> Vec<FrameInfo<'tcx>> {
774 let mut last_span = None;
775 let mut frames = Vec::new();
776 for &Frame { instance, span, body, block, stmt, .. } in self.stack().iter().rev() {
777 // make sure we don't emit frames that are duplicates of the previous
778 if explicit_span == Some(span) {
779 last_span = Some(span);
782 if let Some(last) = last_span {
787 last_span = Some(span);
789 let block = &body.basic_blocks()[block];
790 let source_info = if stmt < block.statements.len() {
791 block.statements[stmt].source_info
793 block.terminator().source_info
795 let lint_root = match body.source_scope_local_data {
796 mir::ClearCrossCrate::Set(ref ivs) => Some(ivs[source_info.scope].lint_root),
797 mir::ClearCrossCrate::Clear => None,
799 frames.push(FrameInfo { call_site: span, instance, lint_root });
801 trace!("generate stacktrace: {:#?}, {:?}", frames, explicit_span);