| //! Functions concerning immediate values and operands, and reading from operands. |
| //! All high-level functions to read from memory work on operands as sources. |
| |
| use std::assert_matches::assert_matches; |
| |
| use either::{Either, Left, Right}; |
| |
| use rustc_hir::def::Namespace; |
| use rustc_middle::ty::layout::{LayoutOf, TyAndLayout}; |
| use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter}; |
| use rustc_middle::ty::{ConstInt, Ty, TyCtxt}; |
| use rustc_middle::{mir, ty}; |
| use rustc_target::abi::{self, Abi, HasDataLayout, Size}; |
| |
| use super::{ |
| alloc_range, from_known_layout, mir_assign_valid_types, AllocId, Frame, InterpCx, InterpResult, |
| MPlaceTy, Machine, MemPlace, MemPlaceMeta, OffsetMode, PlaceTy, Pointer, Projectable, |
| Provenance, Scalar, |
| }; |
| |
| /// An `Immediate` represents a single immediate self-contained Rust value. |
| /// |
| /// For optimization of a few very common cases, there is also a representation for a pair of |
| /// primitive values (`ScalarPair`). It allows Miri to avoid making allocations for checked binary |
| /// operations and wide pointers. This idea was taken from rustc's codegen. |
| /// In particular, thanks to `ScalarPair`, arithmetic operations and casts can be entirely |
| /// defined on `Immediate`, and do not have to work with a `Place`. |
| #[derive(Copy, Clone, Debug)] |
| pub enum Immediate<Prov: Provenance = AllocId> { |
| /// A single scalar value (must have *initialized* `Scalar` ABI). |
| Scalar(Scalar<Prov>), |
| /// A pair of two scalar value (must have `ScalarPair` ABI where both fields are |
| /// `Scalar::Initialized`). |
| ScalarPair(Scalar<Prov>, Scalar<Prov>), |
| /// A value of fully uninitialized memory. Can have arbitrary size and layout, but must be sized. |
| Uninit, |
| } |
| |
| impl<Prov: Provenance> From<Scalar<Prov>> for Immediate<Prov> { |
| #[inline(always)] |
| fn from(val: Scalar<Prov>) -> Self { |
| Immediate::Scalar(val) |
| } |
| } |
| |
| impl<Prov: Provenance> Immediate<Prov> { |
| pub fn new_pointer_with_meta( |
| ptr: Pointer<Option<Prov>>, |
| meta: MemPlaceMeta<Prov>, |
| cx: &impl HasDataLayout, |
| ) -> Self { |
| let ptr = Scalar::from_maybe_pointer(ptr, cx); |
| match meta { |
| MemPlaceMeta::None => Immediate::from(ptr), |
| MemPlaceMeta::Meta(meta) => Immediate::ScalarPair(ptr, meta), |
| } |
| } |
| |
| pub fn new_slice(ptr: Pointer<Option<Prov>>, len: u64, cx: &impl HasDataLayout) -> Self { |
| Immediate::ScalarPair( |
| Scalar::from_maybe_pointer(ptr, cx), |
| Scalar::from_target_usize(len, cx), |
| ) |
| } |
| |
| pub fn new_dyn_trait( |
| val: Pointer<Option<Prov>>, |
| vtable: Pointer<Option<Prov>>, |
| cx: &impl HasDataLayout, |
| ) -> Self { |
| Immediate::ScalarPair( |
| Scalar::from_maybe_pointer(val, cx), |
| Scalar::from_maybe_pointer(vtable, cx), |
| ) |
| } |
| |
| #[inline] |
| #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) |
| pub fn to_scalar(self) -> Scalar<Prov> { |
| match self { |
| Immediate::Scalar(val) => val, |
| Immediate::ScalarPair(..) => bug!("Got a scalar pair where a scalar was expected"), |
| Immediate::Uninit => bug!("Got uninit where a scalar was expected"), |
| } |
| } |
| |
| #[inline] |
| #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) |
| pub fn to_scalar_pair(self) -> (Scalar<Prov>, Scalar<Prov>) { |
| match self { |
| Immediate::ScalarPair(val1, val2) => (val1, val2), |
| Immediate::Scalar(..) => bug!("Got a scalar where a scalar pair was expected"), |
| Immediate::Uninit => bug!("Got uninit where a scalar pair was expected"), |
| } |
| } |
| } |
| |
| // ScalarPair needs a type to interpret, so we often have an immediate and a type together |
| // as input for binary and cast operations. |
| #[derive(Clone)] |
| pub struct ImmTy<'tcx, Prov: Provenance = AllocId> { |
| imm: Immediate<Prov>, |
| pub layout: TyAndLayout<'tcx>, |
| } |
| |
| impl<Prov: Provenance> std::fmt::Display for ImmTy<'_, Prov> { |
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| /// Helper function for printing a scalar to a FmtPrinter |
| fn p<'a, 'tcx, Prov: Provenance>( |
| cx: &mut FmtPrinter<'a, 'tcx>, |
| s: Scalar<Prov>, |
| ty: Ty<'tcx>, |
| ) -> Result<(), std::fmt::Error> { |
| match s { |
| Scalar::Int(int) => cx.pretty_print_const_scalar_int(int, ty, true), |
| Scalar::Ptr(ptr, _sz) => { |
| // Just print the ptr value. `pretty_print_const_scalar_ptr` would also try to |
| // print what is points to, which would fail since it has no access to the local |
| // memory. |
| cx.pretty_print_const_pointer(ptr, ty) |
| } |
| } |
| } |
| ty::tls::with(|tcx| { |
| match self.imm { |
| Immediate::Scalar(s) => { |
| if let Some(ty) = tcx.lift(self.layout.ty) { |
| let s = |
| FmtPrinter::print_string(tcx, Namespace::ValueNS, |cx| p(cx, s, ty))?; |
| f.write_str(&s)?; |
| return Ok(()); |
| } |
| write!(f, "{:x}: {}", s, self.layout.ty) |
| } |
| Immediate::ScalarPair(a, b) => { |
| // FIXME(oli-obk): at least print tuples and slices nicely |
| write!(f, "({:x}, {:x}): {}", a, b, self.layout.ty) |
| } |
| Immediate::Uninit => { |
| write!(f, "uninit: {}", self.layout.ty) |
| } |
| } |
| }) |
| } |
| } |
| |
| impl<Prov: Provenance> std::fmt::Debug for ImmTy<'_, Prov> { |
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| // Printing `layout` results in too much noise; just print a nice version of the type. |
| f.debug_struct("ImmTy") |
| .field("imm", &self.imm) |
| .field("ty", &format_args!("{}", self.layout.ty)) |
| .finish() |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> std::ops::Deref for ImmTy<'tcx, Prov> { |
| type Target = Immediate<Prov>; |
| #[inline(always)] |
| fn deref(&self) -> &Immediate<Prov> { |
| &self.imm |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> ImmTy<'tcx, Prov> { |
| #[inline] |
| pub fn from_scalar(val: Scalar<Prov>, layout: TyAndLayout<'tcx>) -> Self { |
| debug_assert!(layout.abi.is_scalar(), "`ImmTy::from_scalar` on non-scalar layout"); |
| ImmTy { imm: val.into(), layout } |
| } |
| |
| #[inline] |
| pub fn from_scalar_pair(a: Scalar<Prov>, b: Scalar<Prov>, layout: TyAndLayout<'tcx>) -> Self { |
| debug_assert!( |
| matches!(layout.abi, Abi::ScalarPair(..)), |
| "`ImmTy::from_scalar_pair` on non-scalar-pair layout" |
| ); |
| let imm = Immediate::ScalarPair(a, b); |
| ImmTy { imm, layout } |
| } |
| |
| #[inline(always)] |
| pub fn from_immediate(imm: Immediate<Prov>, layout: TyAndLayout<'tcx>) -> Self { |
| debug_assert!( |
| match (imm, layout.abi) { |
| (Immediate::Scalar(..), Abi::Scalar(..)) => true, |
| (Immediate::ScalarPair(..), Abi::ScalarPair(..)) => true, |
| (Immediate::Uninit, _) if layout.is_sized() => true, |
| _ => false, |
| }, |
| "immediate {imm:?} does not fit to layout {layout:?}", |
| ); |
| ImmTy { imm, layout } |
| } |
| |
| #[inline] |
| pub fn uninit(layout: TyAndLayout<'tcx>) -> Self { |
| debug_assert!(layout.is_sized(), "immediates must be sized"); |
| ImmTy { imm: Immediate::Uninit, layout } |
| } |
| |
| #[inline] |
| pub fn try_from_uint(i: impl Into<u128>, layout: TyAndLayout<'tcx>) -> Option<Self> { |
| Some(Self::from_scalar(Scalar::try_from_uint(i, layout.size)?, layout)) |
| } |
| #[inline] |
| pub fn from_uint(i: impl Into<u128>, layout: TyAndLayout<'tcx>) -> Self { |
| Self::from_scalar(Scalar::from_uint(i, layout.size), layout) |
| } |
| |
| #[inline] |
| pub fn try_from_int(i: impl Into<i128>, layout: TyAndLayout<'tcx>) -> Option<Self> { |
| Some(Self::from_scalar(Scalar::try_from_int(i, layout.size)?, layout)) |
| } |
| |
| #[inline] |
| pub fn from_int(i: impl Into<i128>, layout: TyAndLayout<'tcx>) -> Self { |
| Self::from_scalar(Scalar::from_int(i, layout.size), layout) |
| } |
| |
| #[inline] |
| pub fn from_bool(b: bool, tcx: TyCtxt<'tcx>) -> Self { |
| let layout = tcx.layout_of(ty::ParamEnv::reveal_all().and(tcx.types.bool)).unwrap(); |
| Self::from_scalar(Scalar::from_bool(b), layout) |
| } |
| |
| #[inline] |
| pub fn to_const_int(self) -> ConstInt { |
| assert!(self.layout.ty.is_integral()); |
| let int = self.to_scalar().assert_int(); |
| ConstInt::new(int, self.layout.ty.is_signed(), self.layout.ty.is_ptr_sized_integral()) |
| } |
| |
| /// Compute the "sub-immediate" that is located within the `base` at the given offset with the |
| /// given layout. |
| // Not called `offset` to avoid confusion with the trait method. |
| fn offset_(&self, offset: Size, layout: TyAndLayout<'tcx>, cx: &impl HasDataLayout) -> Self { |
| debug_assert!(layout.is_sized(), "unsized immediates are not a thing"); |
| // `ImmTy` have already been checked to be in-bounds, so we can just check directly if this |
| // remains in-bounds. This cannot actually be violated since projections are type-checked |
| // and bounds-checked. |
| assert!( |
| offset + layout.size <= self.layout.size, |
| "attempting to project to field at offset {} with size {} into immediate with layout {:#?}", |
| offset.bytes(), |
| layout.size.bytes(), |
| self.layout, |
| ); |
| // This makes several assumptions about what layouts we will encounter; we match what |
| // codegen does as good as we can (see `extract_field` in `rustc_codegen_ssa/src/mir/operand.rs`). |
| let inner_val: Immediate<_> = match (**self, self.layout.abi) { |
| // if the entire value is uninit, then so is the field (can happen in ConstProp) |
| (Immediate::Uninit, _) => Immediate::Uninit, |
| // the field contains no information, can be left uninit |
| // (Scalar/ScalarPair can contain even aligned ZST, not just 1-ZST) |
| _ if layout.is_zst() => Immediate::Uninit, |
| // some fieldless enum variants can have non-zero size but still `Aggregate` ABI... try |
| // to detect those here and also give them no data |
| _ if matches!(layout.abi, Abi::Aggregate { .. }) |
| && matches!(&layout.fields, abi::FieldsShape::Arbitrary { offsets, .. } if offsets.len() == 0) => |
| { |
| Immediate::Uninit |
| } |
| // the field covers the entire type |
| _ if layout.size == self.layout.size => { |
| assert_eq!(offset.bytes(), 0); |
| assert!( |
| match (self.layout.abi, layout.abi) { |
| (Abi::Scalar(..), Abi::Scalar(..)) => true, |
| (Abi::ScalarPair(..), Abi::ScalarPair(..)) => true, |
| _ => false, |
| }, |
| "cannot project into {} immediate with equally-sized field {}\nouter ABI: {:#?}\nfield ABI: {:#?}", |
| self.layout.ty, |
| layout.ty, |
| self.layout.abi, |
| layout.abi, |
| ); |
| **self |
| } |
| // extract fields from types with `ScalarPair` ABI |
| (Immediate::ScalarPair(a_val, b_val), Abi::ScalarPair(a, b)) => { |
| assert!(matches!(layout.abi, Abi::Scalar(..))); |
| Immediate::from(if offset.bytes() == 0 { |
| debug_assert_eq!(layout.size, a.size(cx)); |
| a_val |
| } else { |
| debug_assert_eq!(offset, a.size(cx).align_to(b.align(cx).abi)); |
| debug_assert_eq!(layout.size, b.size(cx)); |
| b_val |
| }) |
| } |
| // everything else is a bug |
| _ => bug!("invalid field access on immediate {}, layout {:#?}", self, self.layout), |
| }; |
| |
| ImmTy::from_immediate(inner_val, layout) |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for ImmTy<'tcx, Prov> { |
| #[inline(always)] |
| fn layout(&self) -> TyAndLayout<'tcx> { |
| self.layout |
| } |
| |
| #[inline(always)] |
| fn meta(&self) -> MemPlaceMeta<Prov> { |
| debug_assert!(self.layout.is_sized()); // unsized ImmTy can only exist temporarily and should never reach this here |
| MemPlaceMeta::None |
| } |
| |
| fn offset_with_meta<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>( |
| &self, |
| offset: Size, |
| _mode: OffsetMode, |
| meta: MemPlaceMeta<Prov>, |
| layout: TyAndLayout<'tcx>, |
| ecx: &InterpCx<'mir, 'tcx, M>, |
| ) -> InterpResult<'tcx, Self> { |
| assert_matches!(meta, MemPlaceMeta::None); // we can't store this anywhere anyway |
| Ok(self.offset_(offset, layout, ecx)) |
| } |
| |
| fn to_op<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>( |
| &self, |
| _ecx: &InterpCx<'mir, 'tcx, M>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| Ok(self.clone().into()) |
| } |
| } |
| |
| /// An `Operand` is the result of computing a `mir::Operand`. It can be immediate, |
| /// or still in memory. The latter is an optimization, to delay reading that chunk of |
| /// memory and to avoid having to store arbitrary-sized data here. |
| #[derive(Copy, Clone, Debug)] |
| pub(super) enum Operand<Prov: Provenance = AllocId> { |
| Immediate(Immediate<Prov>), |
| Indirect(MemPlace<Prov>), |
| } |
| |
| #[derive(Clone)] |
| pub struct OpTy<'tcx, Prov: Provenance = AllocId> { |
| op: Operand<Prov>, // Keep this private; it helps enforce invariants. |
| pub layout: TyAndLayout<'tcx>, |
| } |
| |
| impl<Prov: Provenance> std::fmt::Debug for OpTy<'_, Prov> { |
| fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { |
| // Printing `layout` results in too much noise; just print a nice version of the type. |
| f.debug_struct("OpTy") |
| .field("op", &self.op) |
| .field("ty", &format_args!("{}", self.layout.ty)) |
| .finish() |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> From<ImmTy<'tcx, Prov>> for OpTy<'tcx, Prov> { |
| #[inline(always)] |
| fn from(val: ImmTy<'tcx, Prov>) -> Self { |
| OpTy { op: Operand::Immediate(val.imm), layout: val.layout } |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> From<MPlaceTy<'tcx, Prov>> for OpTy<'tcx, Prov> { |
| #[inline(always)] |
| fn from(mplace: MPlaceTy<'tcx, Prov>) -> Self { |
| OpTy { op: Operand::Indirect(*mplace.mplace()), layout: mplace.layout } |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> OpTy<'tcx, Prov> { |
| #[inline(always)] |
| pub(super) fn op(&self) -> &Operand<Prov> { |
| &self.op |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Projectable<'tcx, Prov> for OpTy<'tcx, Prov> { |
| #[inline(always)] |
| fn layout(&self) -> TyAndLayout<'tcx> { |
| self.layout |
| } |
| |
| #[inline] |
| fn meta(&self) -> MemPlaceMeta<Prov> { |
| match self.as_mplace_or_imm() { |
| Left(mplace) => mplace.meta(), |
| Right(_) => { |
| debug_assert!(self.layout.is_sized(), "unsized immediates are not a thing"); |
| MemPlaceMeta::None |
| } |
| } |
| } |
| |
| fn offset_with_meta<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>( |
| &self, |
| offset: Size, |
| mode: OffsetMode, |
| meta: MemPlaceMeta<Prov>, |
| layout: TyAndLayout<'tcx>, |
| ecx: &InterpCx<'mir, 'tcx, M>, |
| ) -> InterpResult<'tcx, Self> { |
| match self.as_mplace_or_imm() { |
| Left(mplace) => Ok(mplace.offset_with_meta(offset, mode, meta, layout, ecx)?.into()), |
| Right(imm) => { |
| assert_matches!(meta, MemPlaceMeta::None); // no place to store metadata here |
| // Every part of an uninit is uninit. |
| Ok(imm.offset_(offset, layout, ecx).into()) |
| } |
| } |
| } |
| |
| fn to_op<'mir, M: Machine<'mir, 'tcx, Provenance = Prov>>( |
| &self, |
| _ecx: &InterpCx<'mir, 'tcx, M>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| Ok(self.clone()) |
| } |
| } |
| |
| /// The `Readable` trait describes interpreter values that one can read from. |
| pub trait Readable<'tcx, Prov: Provenance>: Projectable<'tcx, Prov> { |
| fn as_mplace_or_imm(&self) -> Either<MPlaceTy<'tcx, Prov>, ImmTy<'tcx, Prov>>; |
| } |
| |
| impl<'tcx, Prov: Provenance> Readable<'tcx, Prov> for OpTy<'tcx, Prov> { |
| #[inline(always)] |
| fn as_mplace_or_imm(&self) -> Either<MPlaceTy<'tcx, Prov>, ImmTy<'tcx, Prov>> { |
| self.as_mplace_or_imm() |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Readable<'tcx, Prov> for MPlaceTy<'tcx, Prov> { |
| #[inline(always)] |
| fn as_mplace_or_imm(&self) -> Either<MPlaceTy<'tcx, Prov>, ImmTy<'tcx, Prov>> { |
| Left(self.clone()) |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Readable<'tcx, Prov> for ImmTy<'tcx, Prov> { |
| #[inline(always)] |
| fn as_mplace_or_imm(&self) -> Either<MPlaceTy<'tcx, Prov>, ImmTy<'tcx, Prov>> { |
| Right(self.clone()) |
| } |
| } |
| |
| impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> { |
| /// Try reading an immediate in memory; this is interesting particularly for `ScalarPair`. |
| /// Returns `None` if the layout does not permit loading this as a value. |
| /// |
| /// This is an internal function; call `read_immediate` instead. |
| fn read_immediate_from_mplace_raw( |
| &self, |
| mplace: &MPlaceTy<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, Option<ImmTy<'tcx, M::Provenance>>> { |
| if mplace.layout.is_unsized() { |
| // Don't touch unsized |
| return Ok(None); |
| } |
| |
| let Some(alloc) = self.get_place_alloc(mplace)? else { |
| // zero-sized type can be left uninit |
| return Ok(Some(ImmTy::uninit(mplace.layout))); |
| }; |
| |
| // It may seem like all types with `Scalar` or `ScalarPair` ABI are fair game at this point. |
| // However, `MaybeUninit<u64>` is considered a `Scalar` as far as its layout is concerned -- |
| // and yet cannot be represented by an interpreter `Scalar`, since we have to handle the |
| // case where some of the bytes are initialized and others are not. So, we need an extra |
| // check that walks over the type of `mplace` to make sure it is truly correct to treat this |
| // like a `Scalar` (or `ScalarPair`). |
| Ok(match mplace.layout.abi { |
| Abi::Scalar(abi::Scalar::Initialized { value: s, .. }) => { |
| let size = s.size(self); |
| assert_eq!(size, mplace.layout.size, "abi::Scalar size does not match layout size"); |
| let scalar = alloc.read_scalar( |
| alloc_range(Size::ZERO, size), |
| /*read_provenance*/ matches!(s, abi::Pointer(_)), |
| )?; |
| Some(ImmTy::from_scalar(scalar, mplace.layout)) |
| } |
| Abi::ScalarPair( |
| abi::Scalar::Initialized { value: a, .. }, |
| abi::Scalar::Initialized { value: b, .. }, |
| ) => { |
| // We checked `ptr_align` above, so all fields will have the alignment they need. |
| // We would anyway check against `ptr_align.restrict_for_offset(b_offset)`, |
| // which `ptr.offset(b_offset)` cannot possibly fail to satisfy. |
| let (a_size, b_size) = (a.size(self), b.size(self)); |
| let b_offset = a_size.align_to(b.align(self).abi); |
| assert!(b_offset.bytes() > 0); // in `operand_field` we use the offset to tell apart the fields |
| let a_val = alloc.read_scalar( |
| alloc_range(Size::ZERO, a_size), |
| /*read_provenance*/ matches!(a, abi::Pointer(_)), |
| )?; |
| let b_val = alloc.read_scalar( |
| alloc_range(b_offset, b_size), |
| /*read_provenance*/ matches!(b, abi::Pointer(_)), |
| )?; |
| Some(ImmTy::from_immediate(Immediate::ScalarPair(a_val, b_val), mplace.layout)) |
| } |
| _ => { |
| // Neither a scalar nor scalar pair. |
| None |
| } |
| }) |
| } |
| |
| /// Try returning an immediate for the operand. If the layout does not permit loading this as an |
| /// immediate, return where in memory we can find the data. |
| /// Note that for a given layout, this operation will either always return Left or Right! |
| /// succeed! Whether it returns Left depends on whether the layout can be represented |
| /// in an `Immediate`, not on which data is stored there currently. |
| /// |
| /// This is an internal function that should not usually be used; call `read_immediate` instead. |
| /// ConstProp needs it, though. |
| pub fn read_immediate_raw( |
| &self, |
| src: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, Either<MPlaceTy<'tcx, M::Provenance>, ImmTy<'tcx, M::Provenance>>> { |
| Ok(match src.as_mplace_or_imm() { |
| Left(ref mplace) => { |
| if let Some(val) = self.read_immediate_from_mplace_raw(mplace)? { |
| Right(val) |
| } else { |
| Left(mplace.clone()) |
| } |
| } |
| Right(val) => Right(val), |
| }) |
| } |
| |
| /// Read an immediate from a place, asserting that that is possible with the given layout. |
| /// |
| /// If this succeeds, the `ImmTy` is never `Uninit`. |
| #[inline(always)] |
| pub fn read_immediate( |
| &self, |
| op: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, ImmTy<'tcx, M::Provenance>> { |
| if !matches!( |
| op.layout().abi, |
| Abi::Scalar(abi::Scalar::Initialized { .. }) |
| | Abi::ScalarPair(abi::Scalar::Initialized { .. }, abi::Scalar::Initialized { .. }) |
| ) { |
| span_bug!(self.cur_span(), "primitive read not possible for type: {}", op.layout().ty); |
| } |
| let imm = self.read_immediate_raw(op)?.right().unwrap(); |
| if matches!(*imm, Immediate::Uninit) { |
| throw_ub!(InvalidUninitBytes(None)); |
| } |
| Ok(imm) |
| } |
| |
| /// Read a scalar from a place |
| pub fn read_scalar( |
| &self, |
| op: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, Scalar<M::Provenance>> { |
| Ok(self.read_immediate(op)?.to_scalar()) |
| } |
| |
| // Pointer-sized reads are fairly common and need target layout access, so we wrap them in |
| // convenience functions. |
| |
| /// Read a pointer from a place. |
| pub fn read_pointer( |
| &self, |
| op: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, Pointer<Option<M::Provenance>>> { |
| self.read_scalar(op)?.to_pointer(self) |
| } |
| /// Read a pointer-sized unsigned integer from a place. |
| pub fn read_target_usize( |
| &self, |
| op: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, u64> { |
| self.read_scalar(op)?.to_target_usize(self) |
| } |
| /// Read a pointer-sized signed integer from a place. |
| pub fn read_target_isize( |
| &self, |
| op: &impl Readable<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, i64> { |
| self.read_scalar(op)?.to_target_isize(self) |
| } |
| |
| /// Turn the wide MPlace into a string (must already be dereferenced!) |
| pub fn read_str(&self, mplace: &MPlaceTy<'tcx, M::Provenance>) -> InterpResult<'tcx, &str> { |
| let len = mplace.len(self)?; |
| let bytes = self.read_bytes_ptr_strip_provenance(mplace.ptr(), Size::from_bytes(len))?; |
| let str = std::str::from_utf8(bytes).map_err(|err| err_ub!(InvalidStr(err)))?; |
| Ok(str) |
| } |
| |
| /// Converts a repr(simd) operand into an operand where `place_index` accesses the SIMD elements. |
| /// Also returns the number of elements. |
| /// |
| /// Can (but does not always) trigger UB if `op` is uninitialized. |
| pub fn operand_to_simd( |
| &self, |
| op: &OpTy<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, (MPlaceTy<'tcx, M::Provenance>, u64)> { |
| // Basically we just transmute this place into an array following simd_size_and_type. |
| // This only works in memory, but repr(simd) types should never be immediates anyway. |
| assert!(op.layout.ty.is_simd()); |
| match op.as_mplace_or_imm() { |
| Left(mplace) => self.mplace_to_simd(&mplace), |
| Right(imm) => match *imm { |
| Immediate::Uninit => { |
| throw_ub!(InvalidUninitBytes(None)) |
| } |
| Immediate::Scalar(..) | Immediate::ScalarPair(..) => { |
| bug!("arrays/slices can never have Scalar/ScalarPair layout") |
| } |
| }, |
| } |
| } |
| |
| /// Read from a local. |
| /// Will not access memory, instead an indirect `Operand` is returned. |
| /// |
| /// This is public because it is used by [priroda](https://github.com/oli-obk/priroda) to get an |
| /// OpTy from a local. |
| pub fn local_to_op( |
| &self, |
| frame: &Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>, |
| local: mir::Local, |
| layout: Option<TyAndLayout<'tcx>>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| let layout = self.layout_of_local(frame, local, layout)?; |
| let op = *frame.locals[local].access()?; |
| if matches!(op, Operand::Immediate(_)) { |
| if layout.is_unsized() { |
| // ConstProp marks *all* locals as `Immediate::Uninit` since it cannot |
| // efficiently check whether they are sized. We have to catch that case here. |
| throw_inval!(ConstPropNonsense); |
| } |
| } |
| Ok(OpTy { op, layout }) |
| } |
| |
| /// Every place can be read from, so we can turn them into an operand. |
| /// This will definitely return `Indirect` if the place is a `Ptr`, i.e., this |
| /// will never actually read from memory. |
| pub fn place_to_op( |
| &self, |
| place: &PlaceTy<'tcx, M::Provenance>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| match place.as_mplace_or_local() { |
| Left(mplace) => Ok(mplace.into()), |
| Right((frame, local, offset)) => { |
| debug_assert!(place.layout.is_sized()); // only sized locals can ever be `Place::Local`. |
| let base = self.local_to_op(&self.stack()[frame], local, None)?; |
| Ok(match offset { |
| Some(offset) => base.offset(offset, place.layout, self)?, |
| None => { |
| // In the common case this hasn't been projected. |
| debug_assert_eq!(place.layout, base.layout); |
| base |
| } |
| }) |
| } |
| } |
| } |
| |
| /// Evaluate a place with the goal of reading from it. This lets us sometimes |
| /// avoid allocations. |
| pub fn eval_place_to_op( |
| &self, |
| mir_place: mir::Place<'tcx>, |
| layout: Option<TyAndLayout<'tcx>>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| // Do not use the layout passed in as argument if the base we are looking at |
| // here is not the entire place. |
| let layout = if mir_place.projection.is_empty() { layout } else { None }; |
| |
| let mut op = self.local_to_op(self.frame(), mir_place.local, layout)?; |
| // Using `try_fold` turned out to be bad for performance, hence the loop. |
| for elem in mir_place.projection.iter() { |
| op = self.project(&op, elem)? |
| } |
| |
| trace!("eval_place_to_op: got {:?}", op); |
| // Sanity-check the type we ended up with. |
| if cfg!(debug_assertions) { |
| let normalized_place_ty = self.subst_from_current_frame_and_normalize_erasing_regions( |
| mir_place.ty(&self.frame().body.local_decls, *self.tcx).ty, |
| )?; |
| if !mir_assign_valid_types( |
| *self.tcx, |
| self.param_env, |
| self.layout_of(normalized_place_ty)?, |
| op.layout, |
| ) { |
| span_bug!( |
| self.cur_span(), |
| "eval_place of a MIR place with type {} produced an interpreter operand with type {}", |
| normalized_place_ty, |
| op.layout.ty, |
| ) |
| } |
| } |
| Ok(op) |
| } |
| |
| /// Evaluate the operand, returning a place where you can then find the data. |
| /// If you already know the layout, you can save two table lookups |
| /// by passing it in here. |
| #[inline] |
| pub fn eval_operand( |
| &self, |
| mir_op: &mir::Operand<'tcx>, |
| layout: Option<TyAndLayout<'tcx>>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| use rustc_middle::mir::Operand::*; |
| let op = match mir_op { |
| // FIXME: do some more logic on `move` to invalidate the old location |
| &Copy(place) | &Move(place) => self.eval_place_to_op(place, layout)?, |
| |
| Constant(constant) => { |
| let c = |
| self.subst_from_current_frame_and_normalize_erasing_regions(constant.const_)?; |
| |
| // This can still fail: |
| // * During ConstProp, with `TooGeneric` or since the `required_consts` were not all |
| // checked yet. |
| // * During CTFE, since promoteds in `const`/`static` initializer bodies can fail. |
| self.eval_mir_constant(&c, Some(constant.span), layout)? |
| } |
| }; |
| trace!("{:?}: {:?}", mir_op, op); |
| Ok(op) |
| } |
| |
| pub(crate) fn const_val_to_op( |
| &self, |
| val_val: mir::ConstValue<'tcx>, |
| ty: Ty<'tcx>, |
| layout: Option<TyAndLayout<'tcx>>, |
| ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> { |
| // Other cases need layout. |
| let adjust_scalar = |scalar| -> InterpResult<'tcx, _> { |
| Ok(match scalar { |
| Scalar::Ptr(ptr, size) => Scalar::Ptr(self.global_base_pointer(ptr)?, size), |
| Scalar::Int(int) => Scalar::Int(int), |
| }) |
| }; |
| let layout = from_known_layout(self.tcx, self.param_env, layout, || self.layout_of(ty))?; |
| let imm = match val_val { |
| mir::ConstValue::Indirect { alloc_id, offset } => { |
| // We rely on mutability being set correctly in that allocation to prevent writes |
| // where none should happen. |
| let ptr = self.global_base_pointer(Pointer::new(alloc_id, offset))?; |
| return Ok(self.ptr_to_mplace(ptr.into(), layout).into()); |
| } |
| mir::ConstValue::Scalar(x) => adjust_scalar(x)?.into(), |
| mir::ConstValue::ZeroSized => Immediate::Uninit, |
| mir::ConstValue::Slice { data, meta } => { |
| // We rely on mutability being set correctly in `data` to prevent writes |
| // where none should happen. |
| let ptr = Pointer::new(self.tcx.reserve_and_set_memory_alloc(data), Size::ZERO); |
| Immediate::new_slice(self.global_base_pointer(ptr)?.into(), meta, self) |
| } |
| }; |
| Ok(OpTy { op: Operand::Immediate(imm), layout }) |
| } |
| } |
| |
| // Some nodes are used a lot. Make sure they don't unintentionally get bigger. |
| #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] |
| mod size_asserts { |
| use super::*; |
| use rustc_data_structures::static_assert_size; |
| // tidy-alphabetical-start |
| static_assert_size!(Immediate, 48); |
| static_assert_size!(ImmTy<'_>, 64); |
| static_assert_size!(Operand, 56); |
| static_assert_size!(OpTy<'_>, 72); |
| // tidy-alphabetical-end |
| } |
