| //! Manages the low-level pushing and popping of stack frames and the (de)allocation of local variables. |
| //! For handling of argument passing and return values, see the `call` module. |
| use std::cell::Cell; |
| use std::{fmt, mem}; |
| |
| use either::{Either, Left, Right}; |
| use rustc_hir as hir; |
| use rustc_hir::definitions::DefPathData; |
| use rustc_index::IndexVec; |
| use rustc_middle::ty::layout::TyAndLayout; |
| use rustc_middle::ty::{self, Ty, TyCtxt}; |
| use rustc_middle::{bug, mir}; |
| use rustc_mir_dataflow::impls::always_storage_live_locals; |
| use rustc_span::Span; |
| use tracing::field::Empty; |
| use tracing::{info_span, instrument, trace}; |
| |
| use super::{ |
| AllocId, CtfeProvenance, Immediate, InterpCx, InterpResult, Machine, MemPlace, MemPlaceMeta, |
| MemoryKind, Operand, PlaceTy, Pointer, Provenance, ReturnAction, Scalar, from_known_layout, |
| interp_ok, throw_ub, throw_unsup, |
| }; |
| use crate::errors; |
| |
| // The Phantomdata exists to prevent this type from being `Send`. If it were sent across a thread |
| // boundary and dropped in the other thread, it would exit the span in the other thread. |
| struct SpanGuard(tracing::Span, std::marker::PhantomData<*const u8>); |
| |
| impl SpanGuard { |
| /// By default a `SpanGuard` does nothing. |
| fn new() -> Self { |
| Self(tracing::Span::none(), std::marker::PhantomData) |
| } |
| |
| /// If a span is entered, we exit the previous span (if any, normally none) and enter the |
| /// new span. This is mainly so we don't have to use `Option` for the `tracing_span` field of |
| /// `Frame` by creating a dummy span to being with and then entering it once the frame has |
| /// been pushed. |
| fn enter(&mut self, span: tracing::Span) { |
| // This executes the destructor on the previous instance of `SpanGuard`, ensuring that |
| // we never enter or exit more spans than vice versa. Unless you `mem::leak`, then we |
| // can't protect the tracing stack, but that'll just lead to weird logging, no actual |
| // problems. |
| *self = Self(span, std::marker::PhantomData); |
| self.0.with_subscriber(|(id, dispatch)| { |
| dispatch.enter(id); |
| }); |
| } |
| } |
| |
| impl Drop for SpanGuard { |
| fn drop(&mut self) { |
| self.0.with_subscriber(|(id, dispatch)| { |
| dispatch.exit(id); |
| }); |
| } |
| } |
| |
| /// A stack frame. |
| pub struct Frame<'tcx, Prov: Provenance = CtfeProvenance, Extra = ()> { |
| //////////////////////////////////////////////////////////////////////////////// |
| // Function and callsite information |
| //////////////////////////////////////////////////////////////////////////////// |
| /// The MIR for the function called on this frame. |
| pub(super) body: &'tcx mir::Body<'tcx>, |
| |
| /// The def_id and args of the current function. |
| pub(super) instance: ty::Instance<'tcx>, |
| |
| /// Extra data for the machine. |
| pub extra: Extra, |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Return place and locals |
| //////////////////////////////////////////////////////////////////////////////// |
| /// Where to continue when returning from this function. |
| return_cont: ReturnContinuation, |
| |
| /// The location where the result of the current stack frame should be written to, |
| /// and its layout in the caller. This place is to be interpreted relative to the |
| /// *caller's* stack frame. We use a `PlaceTy` instead of an `MPlaceTy` since this |
| /// avoids having to move *all* return places into Miri's memory. |
| pub return_place: PlaceTy<'tcx, Prov>, |
| |
| /// The list of locals for this stack frame, stored in order as |
| /// `[return_ptr, arguments..., variables..., temporaries...]`. |
| /// The locals are stored as `Option<Value>`s. |
| /// `None` represents a local that is currently dead, while a live local |
| /// can either directly contain `Scalar` or refer to some part of an `Allocation`. |
| /// |
| /// Do *not* access this directly; always go through the machine hook! |
| pub locals: IndexVec<mir::Local, LocalState<'tcx, Prov>>, |
| |
| /// The span of the `tracing` crate is stored here. |
| /// When the guard is dropped, the span is exited. This gives us |
| /// a full stack trace on all tracing statements. |
| tracing_span: SpanGuard, |
| |
| //////////////////////////////////////////////////////////////////////////////// |
| // Current position within the function |
| //////////////////////////////////////////////////////////////////////////////// |
| /// If this is `Right`, we are not currently executing any particular statement in |
| /// this frame (can happen e.g. during frame initialization, and during unwinding on |
| /// frames without cleanup code). |
| /// |
| /// Needs to be public because ConstProp does unspeakable things to it. |
| pub(super) loc: Either<mir::Location, Span>, |
| } |
| |
| /// Where and how to continue when returning/unwinding from the current function. |
| #[derive(Clone, Copy, Eq, PartialEq, Debug)] // Miri debug-prints these |
| pub enum ReturnContinuation { |
| /// Jump to the next block in the caller, or cause UB if None (that's a function |
| /// that may never return). |
| /// `ret` stores the block we jump to on a normal return, while `unwind` |
| /// stores the block used for cleanup during unwinding. |
| Goto { ret: Option<mir::BasicBlock>, unwind: mir::UnwindAction }, |
| /// The root frame of the stack: nowhere else to jump to, so we stop. |
| /// `cleanup` says whether locals are deallocated. Static computation |
| /// wants them leaked to intern what they need (and just throw away |
| /// the entire `ecx` when it is done). |
| Stop { cleanup: bool }, |
| } |
| |
| /// Return type of [`InterpCx::pop_stack_frame_raw`]. |
| pub struct StackPopInfo<'tcx, Prov: Provenance> { |
| /// Additional information about the action to be performed when returning from the popped |
| /// stack frame. |
| pub return_action: ReturnAction, |
| |
| /// [`return_cont`](Frame::return_cont) of the popped stack frame. |
| pub return_cont: ReturnContinuation, |
| |
| /// [`return_place`](Frame::return_place) of the popped stack frame. |
| pub return_place: PlaceTy<'tcx, Prov>, |
| } |
| |
| /// State of a local variable including a memoized layout |
| #[derive(Clone)] |
| pub struct LocalState<'tcx, Prov: Provenance = CtfeProvenance> { |
| value: LocalValue<Prov>, |
| /// Don't modify if `Some`, this is only used to prevent computing the layout twice. |
| /// Avoids computing the layout of locals that are never actually initialized. |
| layout: Cell<Option<TyAndLayout<'tcx>>>, |
| } |
| |
| impl<Prov: Provenance> std::fmt::Debug for LocalState<'_, Prov> { |
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| f.debug_struct("LocalState") |
| .field("value", &self.value) |
| .field("ty", &self.layout.get().map(|l| l.ty)) |
| .finish() |
| } |
| } |
| |
| /// Current value of a local variable |
| /// |
| /// This does not store the type of the local; the type is given by `body.local_decls` and can never |
| /// change, so by not storing here we avoid having to maintain that as an invariant. |
| #[derive(Copy, Clone, Debug)] // Miri debug-prints these |
| pub(super) enum LocalValue<Prov: Provenance = CtfeProvenance> { |
| /// This local is not currently alive, and cannot be used at all. |
| Dead, |
| /// A normal, live local. |
| /// Mostly for convenience, we re-use the `Operand` type here. |
| /// This is an optimization over just always having a pointer here; |
| /// we can thus avoid doing an allocation when the local just stores |
| /// immediate values *and* never has its address taken. |
| Live(Operand<Prov>), |
| } |
| |
| impl<'tcx, Prov: Provenance> LocalState<'tcx, Prov> { |
| pub fn make_live_uninit(&mut self) { |
| self.value = LocalValue::Live(Operand::Immediate(Immediate::Uninit)); |
| } |
| |
| /// This is a hack because Miri needs a way to visit all the provenance in a `LocalState` |
| /// without having a layout or `TyCtxt` available, and we want to keep the `Operand` type |
| /// private. |
| pub fn as_mplace_or_imm( |
| &self, |
| ) -> Option<Either<(Pointer<Option<Prov>>, MemPlaceMeta<Prov>), Immediate<Prov>>> { |
| match self.value { |
| LocalValue::Dead => None, |
| LocalValue::Live(Operand::Indirect(mplace)) => Some(Left((mplace.ptr, mplace.meta))), |
| LocalValue::Live(Operand::Immediate(imm)) => Some(Right(imm)), |
| } |
| } |
| |
| /// Read the local's value or error if the local is not yet live or not live anymore. |
| #[inline(always)] |
| pub(super) fn access(&self) -> InterpResult<'tcx, &Operand<Prov>> { |
| match &self.value { |
| LocalValue::Dead => throw_ub!(DeadLocal), // could even be "invalid program"? |
| LocalValue::Live(val) => interp_ok(val), |
| } |
| } |
| |
| /// Overwrite the local. If the local can be overwritten in place, return a reference |
| /// to do so; otherwise return the `MemPlace` to consult instead. |
| #[inline(always)] |
| pub(super) fn access_mut(&mut self) -> InterpResult<'tcx, &mut Operand<Prov>> { |
| match &mut self.value { |
| LocalValue::Dead => throw_ub!(DeadLocal), // could even be "invalid program"? |
| LocalValue::Live(val) => interp_ok(val), |
| } |
| } |
| } |
| |
| /// What we store about a frame in an interpreter backtrace. |
| #[derive(Clone, Debug)] |
| pub struct FrameInfo<'tcx> { |
| pub instance: ty::Instance<'tcx>, |
| pub span: Span, |
| } |
| |
| // FIXME: only used by miri, should be removed once translatable. |
| impl<'tcx> fmt::Display for FrameInfo<'tcx> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| ty::tls::with(|tcx| { |
| if tcx.def_key(self.instance.def_id()).disambiguated_data.data == DefPathData::Closure { |
| write!(f, "inside closure") |
| } else { |
| // Note: this triggers a `must_produce_diag` state, which means that if we ever |
| // get here we must emit a diagnostic. We should never display a `FrameInfo` unless |
| // we actually want to emit a warning or error to the user. |
| write!(f, "inside `{}`", self.instance) |
| } |
| }) |
| } |
| } |
| |
| impl<'tcx> FrameInfo<'tcx> { |
| pub fn as_note(&self, tcx: TyCtxt<'tcx>) -> errors::FrameNote { |
| let span = self.span; |
| if tcx.def_key(self.instance.def_id()).disambiguated_data.data == DefPathData::Closure { |
| errors::FrameNote { |
| where_: "closure", |
| span, |
| instance: String::new(), |
| times: 0, |
| has_label: false, |
| } |
| } else { |
| let instance = format!("{}", self.instance); |
| // Note: this triggers a `must_produce_diag` state, which means that if we ever get |
| // here we must emit a diagnostic. We should never display a `FrameInfo` unless we |
| // actually want to emit a warning or error to the user. |
| errors::FrameNote { where_: "instance", span, instance, times: 0, has_label: false } |
| } |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Frame<'tcx, Prov> { |
| pub fn with_extra<Extra>(self, extra: Extra) -> Frame<'tcx, Prov, Extra> { |
| Frame { |
| body: self.body, |
| instance: self.instance, |
| return_cont: self.return_cont, |
| return_place: self.return_place, |
| locals: self.locals, |
| loc: self.loc, |
| extra, |
| tracing_span: self.tracing_span, |
| } |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance, Extra> Frame<'tcx, Prov, Extra> { |
| /// Get the current location within the Frame. |
| /// |
| /// If this is `Right`, we are not currently executing any particular statement in |
| /// this frame (can happen e.g. during frame initialization, and during unwinding on |
| /// frames without cleanup code). |
| /// |
| /// Used by [priroda](https://github.com/oli-obk/priroda). |
| pub fn current_loc(&self) -> Either<mir::Location, Span> { |
| self.loc |
| } |
| |
| pub fn body(&self) -> &'tcx mir::Body<'tcx> { |
| self.body |
| } |
| |
| pub fn instance(&self) -> ty::Instance<'tcx> { |
| self.instance |
| } |
| |
| /// Return the `SourceInfo` of the current instruction. |
| pub fn current_source_info(&self) -> Option<&mir::SourceInfo> { |
| self.loc.left().map(|loc| self.body.source_info(loc)) |
| } |
| |
| pub fn current_span(&self) -> Span { |
| match self.loc { |
| Left(loc) => self.body.source_info(loc).span, |
| Right(span) => span, |
| } |
| } |
| |
| pub fn lint_root(&self, tcx: TyCtxt<'tcx>) -> Option<hir::HirId> { |
| // We first try to get a HirId via the current source scope, |
| // and fall back to `body.source`. |
| self.current_source_info() |
| .and_then(|source_info| match &self.body.source_scopes[source_info.scope].local_data { |
| mir::ClearCrossCrate::Set(data) => Some(data.lint_root), |
| mir::ClearCrossCrate::Clear => None, |
| }) |
| .or_else(|| { |
| let def_id = self.body.source.def_id().as_local(); |
| def_id.map(|def_id| tcx.local_def_id_to_hir_id(def_id)) |
| }) |
| } |
| |
| /// Returns the address of the buffer where the locals are stored. This is used by `Place` as a |
| /// sanity check to detect bugs where we mix up which stack frame a place refers to. |
| #[inline(always)] |
| pub(super) fn locals_addr(&self) -> usize { |
| self.locals.raw.as_ptr().addr() |
| } |
| |
| #[must_use] |
| pub fn generate_stacktrace_from_stack(stack: &[Self]) -> Vec<FrameInfo<'tcx>> { |
| let mut frames = Vec::new(); |
| // This deliberately does *not* honor `requires_caller_location` since it is used for much |
| // more than just panics. |
| for frame in stack.iter().rev() { |
| let span = match frame.loc { |
| Left(loc) => { |
| // If the stacktrace passes through MIR-inlined source scopes, add them. |
| let mir::SourceInfo { mut span, scope } = *frame.body.source_info(loc); |
| let mut scope_data = &frame.body.source_scopes[scope]; |
| while let Some((instance, call_span)) = scope_data.inlined { |
| frames.push(FrameInfo { span, instance }); |
| span = call_span; |
| scope_data = &frame.body.source_scopes[scope_data.parent_scope.unwrap()]; |
| } |
| span |
| } |
| Right(span) => span, |
| }; |
| frames.push(FrameInfo { span, instance: frame.instance }); |
| } |
| trace!("generate stacktrace: {:#?}", frames); |
| frames |
| } |
| } |
| |
| impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { |
| /// Very low-level helper that pushes a stack frame without initializing |
| /// the arguments or local variables. |
| /// |
| /// The high-level version of this is `init_stack_frame`. |
| #[instrument(skip(self, body, return_place, return_cont), level = "debug")] |
| pub(crate) fn push_stack_frame_raw( |
| &mut self, |
| instance: ty::Instance<'tcx>, |
| body: &'tcx mir::Body<'tcx>, |
| return_place: &PlaceTy<'tcx, M::Provenance>, |
| return_cont: ReturnContinuation, |
| ) -> InterpResult<'tcx> { |
| trace!("body: {:#?}", body); |
| |
| // We can push a `Root` frame if and only if the stack is empty. |
| debug_assert_eq!( |
| self.stack().is_empty(), |
| matches!(return_cont, ReturnContinuation::Stop { .. }) |
| ); |
| |
| // First push a stack frame so we have access to `instantiate_from_current_frame` and other |
| // `self.frame()`-based functions. |
| let dead_local = LocalState { value: LocalValue::Dead, layout: Cell::new(None) }; |
| let locals = IndexVec::from_elem(dead_local, &body.local_decls); |
| let pre_frame = Frame { |
| body, |
| loc: Right(body.span), // Span used for errors caused during preamble. |
| return_cont, |
| return_place: return_place.clone(), |
| locals, |
| instance, |
| tracing_span: SpanGuard::new(), |
| extra: (), |
| }; |
| let frame = M::init_frame(self, pre_frame)?; |
| self.stack_mut().push(frame); |
| |
| // Make sure all the constants required by this frame evaluate successfully (post-monomorphization check). |
| for &const_ in body.required_consts() { |
| let c = |
| self.instantiate_from_current_frame_and_normalize_erasing_regions(const_.const_)?; |
| c.eval(*self.tcx, self.typing_env, const_.span).map_err(|err| { |
| err.emit_note(*self.tcx); |
| err |
| })?; |
| } |
| |
| // Finish things up. |
| M::after_stack_push(self)?; |
| self.frame_mut().loc = Left(mir::Location::START); |
| // `tracing_separate_thread` is used to instruct the tracing_chrome [tracing::Layer] in Miri |
| // to put the "frame" span on a separate trace thread/line than other spans, to make the |
| // visualization in <https://ui.perfetto.dev> easier to interpret. It is set to a value of |
| // [tracing::field::Empty] so that other tracing layers (e.g. the logger) will ignore it. |
| let span = info_span!("frame", tracing_separate_thread = Empty, frame = %instance); |
| self.frame_mut().tracing_span.enter(span); |
| |
| interp_ok(()) |
| } |
| |
| /// Low-level helper that pops a stack frame from the stack and returns some information about |
| /// it. |
| /// |
| /// This also deallocates locals, if necessary. |
| /// `copy_ret_val` gets called after the frame has been taken from the stack but before the locals have been deallocated. |
| /// |
| /// [`M::before_stack_pop`] and [`M::after_stack_pop`] are called by this function |
| /// automatically. |
| /// |
| /// The high-level version of this is `return_from_current_stack_frame`. |
| /// |
| /// [`M::before_stack_pop`]: Machine::before_stack_pop |
| /// [`M::after_stack_pop`]: Machine::after_stack_pop |
| pub(super) fn pop_stack_frame_raw( |
| &mut self, |
| unwinding: bool, |
| copy_ret_val: impl FnOnce(&mut Self, &PlaceTy<'tcx, M::Provenance>) -> InterpResult<'tcx>, |
| ) -> InterpResult<'tcx, StackPopInfo<'tcx, M::Provenance>> { |
| M::before_stack_pop(self)?; |
| let frame = |
| self.stack_mut().pop().expect("tried to pop a stack frame, but there were none"); |
| |
| // Copy return value (unless we are unwinding). |
| if !unwinding { |
| copy_ret_val(self, &frame.return_place)?; |
| } |
| |
| let return_cont = frame.return_cont; |
| let return_place = frame.return_place.clone(); |
| |
| // Cleanup: deallocate locals. |
| // Usually we want to clean up (deallocate locals), but in a few rare cases we don't. |
| // We do this while the frame is still on the stack, so errors point to the callee. |
| let cleanup = match return_cont { |
| ReturnContinuation::Goto { .. } => true, |
| ReturnContinuation::Stop { cleanup, .. } => cleanup, |
| }; |
| |
| let return_action = if cleanup { |
| // We need to take the locals out, since we need to mutate while iterating. |
| for local in &frame.locals { |
| self.deallocate_local(local.value)?; |
| } |
| |
| // Call the machine hook, which determines the next steps. |
| let return_action = M::after_stack_pop(self, frame, unwinding)?; |
| assert_ne!(return_action, ReturnAction::NoCleanup); |
| return_action |
| } else { |
| // We also skip the machine hook when there's no cleanup. This not a real "pop" anyway. |
| ReturnAction::NoCleanup |
| }; |
| |
| interp_ok(StackPopInfo { return_action, return_cont, return_place }) |
| } |
| |
| /// In the current stack frame, mark all locals as live that are not arguments and don't have |
| /// `Storage*` annotations (this includes the return place). |
| pub(crate) fn storage_live_for_always_live_locals(&mut self) -> InterpResult<'tcx> { |
| self.storage_live(mir::RETURN_PLACE)?; |
| |
| let body = self.body(); |
| let always_live = always_storage_live_locals(body); |
| for local in body.vars_and_temps_iter() { |
| if always_live.contains(local) { |
| self.storage_live(local)?; |
| } |
| } |
| interp_ok(()) |
| } |
| |
| pub fn storage_live_dyn( |
| &mut self, |
| local: mir::Local, |
| meta: MemPlaceMeta<M::Provenance>, |
| ) -> InterpResult<'tcx> { |
| trace!("{:?} is now live", local); |
| |
| // We avoid `ty.is_trivially_sized` since that does something expensive for ADTs. |
| fn is_very_trivially_sized(ty: Ty<'_>) -> bool { |
| match ty.kind() { |
| ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) |
| | ty::Uint(_) |
| | ty::Int(_) |
| | ty::Bool |
| | ty::Float(_) |
| | ty::FnDef(..) |
| | ty::FnPtr(..) |
| | ty::RawPtr(..) |
| | ty::Char |
| | ty::Ref(..) |
| | ty::Coroutine(..) |
| | ty::CoroutineWitness(..) |
| | ty::Array(..) |
| | ty::Closure(..) |
| | ty::CoroutineClosure(..) |
| | ty::Never |
| | ty::Error(_) => true, |
| |
| ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => false, |
| |
| ty::Tuple(tys) => tys.last().is_none_or(|ty| is_very_trivially_sized(*ty)), |
| |
| ty::Pat(ty, ..) => is_very_trivially_sized(*ty), |
| |
| // We don't want to do any queries, so there is not much we can do with ADTs. |
| ty::Adt(..) => false, |
| |
| ty::UnsafeBinder(ty) => is_very_trivially_sized(ty.skip_binder()), |
| |
| ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) => false, |
| |
| ty::Infer(ty::TyVar(_)) => false, |
| |
| ty::Bound(..) |
| | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { |
| bug!("`is_very_trivially_sized` applied to unexpected type: {}", ty) |
| } |
| } |
| } |
| |
| // This is a hot function, we avoid computing the layout when possible. |
| // `unsized_` will be `None` for sized types and `Some(layout)` for unsized types. |
| let unsized_ = if is_very_trivially_sized(self.body().local_decls[local].ty) { |
| None |
| } else { |
| // We need the layout. |
| let layout = self.layout_of_local(self.frame(), local, None)?; |
| if layout.is_sized() { None } else { Some(layout) } |
| }; |
| |
| let local_val = LocalValue::Live(if let Some(layout) = unsized_ { |
| if !meta.has_meta() { |
| throw_unsup!(UnsizedLocal); |
| } |
| // Need to allocate some memory, since `Immediate::Uninit` cannot be unsized. |
| let dest_place = self.allocate_dyn(layout, MemoryKind::Stack, meta)?; |
| Operand::Indirect(*dest_place.mplace()) |
| } else { |
| // Just make this an efficient immediate. |
| assert!(!meta.has_meta()); // we're dropping the metadata |
| // Make sure the machine knows this "write" is happening. (This is important so that |
| // races involving local variable allocation can be detected by Miri.) |
| M::after_local_write(self, local, /*storage_live*/ true)?; |
| // Note that not calling `layout_of` here does have one real consequence: |
| // if the type is too big, we'll only notice this when the local is actually initialized, |
| // which is a bit too late -- we should ideally notice this already here, when the memory |
| // is conceptually allocated. But given how rare that error is and that this is a hot function, |
| // we accept this downside for now. |
| Operand::Immediate(Immediate::Uninit) |
| }); |
| |
| // If the local is already live, deallocate its old memory. |
| let old = mem::replace(&mut self.frame_mut().locals[local].value, local_val); |
| self.deallocate_local(old)?; |
| interp_ok(()) |
| } |
| |
| /// Mark a storage as live, killing the previous content. |
| #[inline(always)] |
| pub fn storage_live(&mut self, local: mir::Local) -> InterpResult<'tcx> { |
| self.storage_live_dyn(local, MemPlaceMeta::None) |
| } |
| |
| pub fn storage_dead(&mut self, local: mir::Local) -> InterpResult<'tcx> { |
| assert!(local != mir::RETURN_PLACE, "Cannot make return place dead"); |
| trace!("{:?} is now dead", local); |
| |
| // If the local is already dead, this is a NOP. |
| let old = mem::replace(&mut self.frame_mut().locals[local].value, LocalValue::Dead); |
| self.deallocate_local(old)?; |
| interp_ok(()) |
| } |
| |
| fn deallocate_local(&mut self, local: LocalValue<M::Provenance>) -> InterpResult<'tcx> { |
| if let LocalValue::Live(Operand::Indirect(MemPlace { ptr, .. })) = local { |
| // All locals have a backing allocation, even if the allocation is empty |
| // due to the local having ZST type. Hence we can `unwrap`. |
| trace!( |
| "deallocating local {:?}: {:?}", |
| local, |
| // Locals always have a `alloc_id` (they are never the result of a int2ptr). |
| self.dump_alloc(ptr.provenance.unwrap().get_alloc_id().unwrap()) |
| ); |
| self.deallocate_ptr(ptr, None, MemoryKind::Stack)?; |
| }; |
| interp_ok(()) |
| } |
| |
| /// This is public because it is used by [Aquascope](https://github.com/cognitive-engineering-lab/aquascope/) |
| /// to analyze all the locals in a stack frame. |
| #[inline(always)] |
| pub fn layout_of_local( |
| &self, |
| frame: &Frame<'tcx, M::Provenance, M::FrameExtra>, |
| local: mir::Local, |
| layout: Option<TyAndLayout<'tcx>>, |
| ) -> InterpResult<'tcx, TyAndLayout<'tcx>> { |
| let state = &frame.locals[local]; |
| if let Some(layout) = state.layout.get() { |
| return interp_ok(layout); |
| } |
| |
| let layout = from_known_layout(self.tcx, self.typing_env, layout, || { |
| let local_ty = frame.body.local_decls[local].ty; |
| let local_ty = |
| self.instantiate_from_frame_and_normalize_erasing_regions(frame, local_ty)?; |
| self.layout_of(local_ty).into() |
| })?; |
| |
| // Layouts of locals are requested a lot, so we cache them. |
| state.layout.set(Some(layout)); |
| interp_ok(layout) |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> LocalState<'tcx, Prov> { |
| pub(super) fn print( |
| &self, |
| allocs: &mut Vec<Option<AllocId>>, |
| fmt: &mut std::fmt::Formatter<'_>, |
| ) -> std::fmt::Result { |
| match self.value { |
| LocalValue::Dead => write!(fmt, " is dead")?, |
| LocalValue::Live(Operand::Immediate(Immediate::Uninit)) => { |
| write!(fmt, " is uninitialized")? |
| } |
| LocalValue::Live(Operand::Indirect(mplace)) => { |
| write!( |
| fmt, |
| " by {} ref {:?}:", |
| match mplace.meta { |
| MemPlaceMeta::Meta(meta) => format!(" meta({meta:?})"), |
| MemPlaceMeta::None => String::new(), |
| }, |
| mplace.ptr, |
| )?; |
| allocs.extend(mplace.ptr.provenance.map(Provenance::get_alloc_id)); |
| } |
| LocalValue::Live(Operand::Immediate(Immediate::Scalar(val))) => { |
| write!(fmt, " {val:?}")?; |
| if let Scalar::Ptr(ptr, _size) = val { |
| allocs.push(ptr.provenance.get_alloc_id()); |
| } |
| } |
| LocalValue::Live(Operand::Immediate(Immediate::ScalarPair(val1, val2))) => { |
| write!(fmt, " ({val1:?}, {val2:?})")?; |
| if let Scalar::Ptr(ptr, _size) = val1 { |
| allocs.push(ptr.provenance.get_alloc_id()); |
| } |
| if let Scalar::Ptr(ptr, _size) = val2 { |
| allocs.push(ptr.provenance.get_alloc_id()); |
| } |
| } |
| } |
| |
| Ok(()) |
| } |
| } |
