| use std::fmt; |
| |
| use either::{Either, Left, Right}; |
| |
| use rustc_apfloat::{ |
| ieee::{Double, Single}, |
| Float, |
| }; |
| use rustc_macros::HashStable; |
| use rustc_target::abi::{HasDataLayout, Size}; |
| |
| use crate::ty::{ParamEnv, ScalarInt, Ty, TyCtxt}; |
| |
| use super::{ |
| AllocId, AllocRange, ConstAllocation, InterpResult, Pointer, PointerArithmetic, Provenance, |
| ScalarSizeMismatch, |
| }; |
| |
| /// Represents the result of const evaluation via the `eval_to_allocation` query. |
| #[derive(Copy, Clone, HashStable, TyEncodable, TyDecodable, Debug, Hash, Eq, PartialEq)] |
| pub struct ConstAlloc<'tcx> { |
| /// The value lives here, at offset 0, and that allocation definitely is an `AllocKind::Memory` |
| /// (so you can use `AllocMap::unwrap_memory`). |
| pub alloc_id: AllocId, |
| pub ty: Ty<'tcx>, |
| } |
| |
| /// Represents a constant value in Rust. `Scalar` and `Slice` are optimizations for |
| /// array length computations, enum discriminants and the pattern matching logic. |
| #[derive(Copy, Clone, Debug, Eq, PartialEq, TyEncodable, TyDecodable, Hash)] |
| #[derive(HashStable, Lift)] |
| pub enum ConstValue<'tcx> { |
| /// Used only for types with `layout::abi::Scalar` ABI. |
| /// |
| /// Not using the enum `Value` to encode that this must not be `Uninit`. |
| Scalar(Scalar), |
| |
| /// Only used for ZSTs. |
| ZeroSized, |
| |
| /// Used only for `&[u8]` and `&str` |
| Slice { data: ConstAllocation<'tcx>, start: usize, end: usize }, |
| |
| /// A value not represented/representable by `Scalar` or `Slice` |
| ByRef { |
| /// The backing memory of the value, may contain more memory than needed for just the value |
| /// in order to share `ConstAllocation`s between values |
| alloc: ConstAllocation<'tcx>, |
| /// Offset into `alloc` |
| offset: Size, |
| }, |
| } |
| |
| #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] |
| static_assert_size!(ConstValue<'_>, 32); |
| |
| impl<'tcx> ConstValue<'tcx> { |
| #[inline] |
| pub fn try_to_scalar(&self) -> Option<Scalar<AllocId>> { |
| match *self { |
| ConstValue::ByRef { .. } | ConstValue::Slice { .. } | ConstValue::ZeroSized => None, |
| ConstValue::Scalar(val) => Some(val), |
| } |
| } |
| |
| pub fn try_to_scalar_int(&self) -> Option<ScalarInt> { |
| self.try_to_scalar()?.try_to_int().ok() |
| } |
| |
| pub fn try_to_bits(&self, size: Size) -> Option<u128> { |
| self.try_to_scalar_int()?.to_bits(size).ok() |
| } |
| |
| pub fn try_to_bool(&self) -> Option<bool> { |
| self.try_to_scalar_int()?.try_into().ok() |
| } |
| |
| pub fn try_to_target_usize(&self, tcx: TyCtxt<'tcx>) -> Option<u64> { |
| self.try_to_scalar_int()?.try_to_target_usize(tcx).ok() |
| } |
| |
| pub fn try_to_bits_for_ty( |
| &self, |
| tcx: TyCtxt<'tcx>, |
| param_env: ParamEnv<'tcx>, |
| ty: Ty<'tcx>, |
| ) -> Option<u128> { |
| let size = tcx.layout_of(param_env.with_reveal_all_normalized(tcx).and(ty)).ok()?.size; |
| self.try_to_bits(size) |
| } |
| |
| pub fn from_bool(b: bool) -> Self { |
| ConstValue::Scalar(Scalar::from_bool(b)) |
| } |
| |
| pub fn from_u64(i: u64) -> Self { |
| ConstValue::Scalar(Scalar::from_u64(i)) |
| } |
| |
| pub fn from_u128(i: u128) -> Self { |
| ConstValue::Scalar(Scalar::from_u128(i)) |
| } |
| |
| pub fn from_target_usize(i: u64, cx: &impl HasDataLayout) -> Self { |
| ConstValue::Scalar(Scalar::from_target_usize(i, cx)) |
| } |
| } |
| |
| /// A `Scalar` represents an immediate, primitive value existing outside of a |
| /// `memory::Allocation`. It is in many ways like a small chunk of an `Allocation`, up to 16 bytes in |
| /// size. Like a range of bytes in an `Allocation`, a `Scalar` can either represent the raw bytes |
| /// of a simple value or a pointer into another `Allocation` |
| /// |
| /// These variants would be private if there was a convenient way to achieve that in Rust. |
| /// Do *not* match on a `Scalar`! Use the various `to_*` methods instead. |
| #[derive(Clone, Copy, Eq, PartialEq, TyEncodable, TyDecodable, Hash)] |
| #[derive(HashStable)] |
| pub enum Scalar<Prov = AllocId> { |
| /// The raw bytes of a simple value. |
| Int(ScalarInt), |
| |
| /// A pointer. |
| /// |
| /// We also store the size of the pointer, such that a `Scalar` always knows how big it is. |
| /// The size is always the pointer size of the current target, but this is not information |
| /// that we always have readily available. |
| Ptr(Pointer<Prov>, u8), |
| } |
| |
| #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] |
| static_assert_size!(Scalar, 24); |
| |
| // We want the `Debug` output to be readable as it is used by `derive(Debug)` for |
| // all the Miri types. |
| impl<Prov: Provenance> fmt::Debug for Scalar<Prov> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| Scalar::Ptr(ptr, _size) => write!(f, "{ptr:?}"), |
| Scalar::Int(int) => write!(f, "{int:?}"), |
| } |
| } |
| } |
| |
| impl<Prov: Provenance> fmt::Display for Scalar<Prov> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| Scalar::Ptr(ptr, _size) => write!(f, "pointer to {ptr:?}"), |
| Scalar::Int(int) => write!(f, "{int}"), |
| } |
| } |
| } |
| |
| impl<Prov: Provenance> fmt::LowerHex for Scalar<Prov> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| match self { |
| Scalar::Ptr(ptr, _size) => write!(f, "pointer to {ptr:?}"), |
| Scalar::Int(int) => write!(f, "{int:#x}"), |
| } |
| } |
| } |
| |
| impl<Prov> From<Single> for Scalar<Prov> { |
| #[inline(always)] |
| fn from(f: Single) -> Self { |
| Scalar::from_f32(f) |
| } |
| } |
| |
| impl<Prov> From<Double> for Scalar<Prov> { |
| #[inline(always)] |
| fn from(f: Double) -> Self { |
| Scalar::from_f64(f) |
| } |
| } |
| |
| impl<Prov> From<ScalarInt> for Scalar<Prov> { |
| #[inline(always)] |
| fn from(ptr: ScalarInt) -> Self { |
| Scalar::Int(ptr) |
| } |
| } |
| |
| impl<Prov> Scalar<Prov> { |
| #[inline(always)] |
| pub fn from_pointer(ptr: Pointer<Prov>, cx: &impl HasDataLayout) -> Self { |
| Scalar::Ptr(ptr, u8::try_from(cx.pointer_size().bytes()).unwrap()) |
| } |
| |
| /// Create a Scalar from a pointer with an `Option<_>` provenance (where `None` represents a |
| /// plain integer / "invalid" pointer). |
| pub fn from_maybe_pointer(ptr: Pointer<Option<Prov>>, cx: &impl HasDataLayout) -> Self { |
| match ptr.into_parts() { |
| (Some(prov), offset) => Scalar::from_pointer(Pointer::new(prov, offset), cx), |
| (None, offset) => { |
| Scalar::Int(ScalarInt::try_from_uint(offset.bytes(), cx.pointer_size()).unwrap()) |
| } |
| } |
| } |
| |
| #[inline] |
| pub fn null_ptr(cx: &impl HasDataLayout) -> Self { |
| Scalar::Int(ScalarInt::null(cx.pointer_size())) |
| } |
| |
| #[inline] |
| pub fn from_bool(b: bool) -> Self { |
| Scalar::Int(b.into()) |
| } |
| |
| #[inline] |
| pub fn from_char(c: char) -> Self { |
| Scalar::Int(c.into()) |
| } |
| |
| #[inline] |
| pub fn try_from_uint(i: impl Into<u128>, size: Size) -> Option<Self> { |
| ScalarInt::try_from_uint(i, size).map(Scalar::Int) |
| } |
| |
| #[inline] |
| pub fn from_uint(i: impl Into<u128>, size: Size) -> Self { |
| let i = i.into(); |
| Self::try_from_uint(i, size) |
| .unwrap_or_else(|| bug!("Unsigned value {:#x} does not fit in {} bits", i, size.bits())) |
| } |
| |
| #[inline] |
| pub fn from_u8(i: u8) -> Self { |
| Scalar::Int(i.into()) |
| } |
| |
| #[inline] |
| pub fn from_u16(i: u16) -> Self { |
| Scalar::Int(i.into()) |
| } |
| |
| #[inline] |
| pub fn from_u32(i: u32) -> Self { |
| Scalar::Int(i.into()) |
| } |
| |
| #[inline] |
| pub fn from_u64(i: u64) -> Self { |
| Scalar::Int(i.into()) |
| } |
| |
| #[inline] |
| pub fn from_u128(i: u128) -> Self { |
| Scalar::Int(i.into()) |
| } |
| |
| #[inline] |
| pub fn from_target_usize(i: u64, cx: &impl HasDataLayout) -> Self { |
| Self::from_uint(i, cx.data_layout().pointer_size) |
| } |
| |
| #[inline] |
| pub fn try_from_int(i: impl Into<i128>, size: Size) -> Option<Self> { |
| ScalarInt::try_from_int(i, size).map(Scalar::Int) |
| } |
| |
| #[inline] |
| pub fn from_int(i: impl Into<i128>, size: Size) -> Self { |
| let i = i.into(); |
| Self::try_from_int(i, size) |
| .unwrap_or_else(|| bug!("Signed value {:#x} does not fit in {} bits", i, size.bits())) |
| } |
| |
| #[inline] |
| pub fn from_i32(i: i32) -> Self { |
| Self::from_int(i, Size::from_bits(32)) |
| } |
| |
| #[inline] |
| pub fn from_i64(i: i64) -> Self { |
| Self::from_int(i, Size::from_bits(64)) |
| } |
| |
| #[inline] |
| pub fn from_target_isize(i: i64, cx: &impl HasDataLayout) -> Self { |
| Self::from_int(i, cx.data_layout().pointer_size) |
| } |
| |
| #[inline] |
| pub fn from_f32(f: Single) -> Self { |
| Scalar::Int(f.into()) |
| } |
| |
| #[inline] |
| pub fn from_f64(f: Double) -> Self { |
| Scalar::Int(f.into()) |
| } |
| |
| /// This is almost certainly not the method you want! You should dispatch on the type |
| /// and use `to_{u8,u16,...}`/`scalar_to_ptr` to perform ptr-to-int / int-to-ptr casts as needed. |
| /// |
| /// This method only exists for the benefit of low-level operations that truly need to treat the |
| /// scalar in whatever form it is. |
| /// |
| /// This throws UB (instead of ICEing) on a size mismatch since size mismatches can arise in |
| /// Miri when someone declares a function that we shim (such as `malloc`) with a wrong type. |
| #[inline] |
| pub fn to_bits_or_ptr_internal( |
| self, |
| target_size: Size, |
| ) -> Result<Either<u128, Pointer<Prov>>, ScalarSizeMismatch> { |
| assert_ne!(target_size.bytes(), 0, "you should never look at the bits of a ZST"); |
| Ok(match self { |
| Scalar::Int(int) => Left(int.to_bits(target_size).map_err(|size| { |
| ScalarSizeMismatch { target_size: target_size.bytes(), data_size: size.bytes() } |
| })?), |
| Scalar::Ptr(ptr, sz) => { |
| if target_size.bytes() != u64::from(sz) { |
| return Err(ScalarSizeMismatch { |
| target_size: target_size.bytes(), |
| data_size: sz.into(), |
| }); |
| } |
| Right(ptr) |
| } |
| }) |
| } |
| |
| #[inline] |
| pub fn size(self) -> Size { |
| match self { |
| Scalar::Int(int) => int.size(), |
| Scalar::Ptr(_ptr, sz) => Size::from_bytes(sz), |
| } |
| } |
| } |
| |
| impl<'tcx, Prov: Provenance> Scalar<Prov> { |
| pub fn to_pointer(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, Pointer<Option<Prov>>> { |
| match self |
| .to_bits_or_ptr_internal(cx.pointer_size()) |
| .map_err(|s| err_ub!(ScalarSizeMismatch(s)))? |
| { |
| Right(ptr) => Ok(ptr.into()), |
| Left(bits) => { |
| let addr = u64::try_from(bits).unwrap(); |
| Ok(Pointer::from_addr_invalid(addr)) |
| } |
| } |
| } |
| |
| /// Fundamental scalar-to-int (cast) operation. Many convenience wrappers exist below, that you |
| /// likely want to use instead. |
| /// |
| /// Will perform ptr-to-int casts if needed and possible. |
| /// If that fails, we know the offset is relative, so we return an "erased" Scalar |
| /// (which is useful for error messages but not much else). |
| #[inline] |
| pub fn try_to_int(self) -> Result<ScalarInt, Scalar<AllocId>> { |
| match self { |
| Scalar::Int(int) => Ok(int), |
| Scalar::Ptr(ptr, sz) => { |
| if Prov::OFFSET_IS_ADDR { |
| Ok(ScalarInt::try_from_uint(ptr.offset.bytes(), Size::from_bytes(sz)).unwrap()) |
| } else { |
| // We know `offset` is relative, since `OFFSET_IS_ADDR == false`. |
| let (prov, offset) = ptr.into_parts(); |
| // Because `OFFSET_IS_ADDR == false`, this unwrap can never fail. |
| Err(Scalar::Ptr(Pointer::new(prov.get_alloc_id().unwrap(), offset), sz)) |
| } |
| } |
| } |
| } |
| |
| #[inline(always)] |
| #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) |
| pub fn assert_int(self) -> ScalarInt { |
| self.try_to_int().unwrap() |
| } |
| |
| /// This throws UB (instead of ICEing) on a size mismatch since size mismatches can arise in |
| /// Miri when someone declares a function that we shim (such as `malloc`) with a wrong type. |
| #[inline] |
| pub fn to_bits(self, target_size: Size) -> InterpResult<'tcx, u128> { |
| assert_ne!(target_size.bytes(), 0, "you should never look at the bits of a ZST"); |
| self.try_to_int() |
| .map_err(|_| err_unsup!(ReadPointerAsInt(None)))? |
| .to_bits(target_size) |
| .map_err(|size| { |
| err_ub!(ScalarSizeMismatch(ScalarSizeMismatch { |
| target_size: target_size.bytes(), |
| data_size: size.bytes(), |
| })) |
| .into() |
| }) |
| } |
| |
| #[inline(always)] |
| #[cfg_attr(debug_assertions, track_caller)] // only in debug builds due to perf (see #98980) |
| pub fn assert_bits(self, target_size: Size) -> u128 { |
| self.to_bits(target_size) |
| .unwrap_or_else(|_| panic!("assertion failed: {self:?} fits {target_size:?}")) |
| } |
| |
| pub fn to_bool(self) -> InterpResult<'tcx, bool> { |
| let val = self.to_u8()?; |
| match val { |
| 0 => Ok(false), |
| 1 => Ok(true), |
| _ => throw_ub!(InvalidBool(val)), |
| } |
| } |
| |
| pub fn to_char(self) -> InterpResult<'tcx, char> { |
| let val = self.to_u32()?; |
| match std::char::from_u32(val) { |
| Some(c) => Ok(c), |
| None => throw_ub!(InvalidChar(val)), |
| } |
| } |
| |
| /// Converts the scalar to produce an unsigned integer of the given size. |
| /// Fails if the scalar is a pointer. |
| #[inline] |
| pub fn to_uint(self, size: Size) -> InterpResult<'tcx, u128> { |
| self.to_bits(size) |
| } |
| |
| /// Converts the scalar to produce a `u8`. Fails if the scalar is a pointer. |
| pub fn to_u8(self) -> InterpResult<'tcx, u8> { |
| self.to_uint(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce a `u16`. Fails if the scalar is a pointer. |
| pub fn to_u16(self) -> InterpResult<'tcx, u16> { |
| self.to_uint(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce a `u32`. Fails if the scalar is a pointer. |
| pub fn to_u32(self) -> InterpResult<'tcx, u32> { |
| self.to_uint(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce a `u64`. Fails if the scalar is a pointer. |
| pub fn to_u64(self) -> InterpResult<'tcx, u64> { |
| self.to_uint(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce a `u128`. Fails if the scalar is a pointer. |
| pub fn to_u128(self) -> InterpResult<'tcx, u128> { |
| self.to_uint(Size::from_bits(128)) |
| } |
| |
| /// Converts the scalar to produce a machine-pointer-sized unsigned integer. |
| /// Fails if the scalar is a pointer. |
| pub fn to_target_usize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, u64> { |
| let b = self.to_uint(cx.data_layout().pointer_size)?; |
| Ok(u64::try_from(b).unwrap()) |
| } |
| |
| /// Converts the scalar to produce a signed integer of the given size. |
| /// Fails if the scalar is a pointer. |
| #[inline] |
| pub fn to_int(self, size: Size) -> InterpResult<'tcx, i128> { |
| let b = self.to_bits(size)?; |
| Ok(size.sign_extend(b) as i128) |
| } |
| |
| /// Converts the scalar to produce an `i8`. Fails if the scalar is a pointer. |
| pub fn to_i8(self) -> InterpResult<'tcx, i8> { |
| self.to_int(Size::from_bits(8)).map(|v| i8::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce an `i16`. Fails if the scalar is a pointer. |
| pub fn to_i16(self) -> InterpResult<'tcx, i16> { |
| self.to_int(Size::from_bits(16)).map(|v| i16::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce an `i32`. Fails if the scalar is a pointer. |
| pub fn to_i32(self) -> InterpResult<'tcx, i32> { |
| self.to_int(Size::from_bits(32)).map(|v| i32::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce an `i64`. Fails if the scalar is a pointer. |
| pub fn to_i64(self) -> InterpResult<'tcx, i64> { |
| self.to_int(Size::from_bits(64)).map(|v| i64::try_from(v).unwrap()) |
| } |
| |
| /// Converts the scalar to produce an `i128`. Fails if the scalar is a pointer. |
| pub fn to_i128(self) -> InterpResult<'tcx, i128> { |
| self.to_int(Size::from_bits(128)) |
| } |
| |
| /// Converts the scalar to produce a machine-pointer-sized signed integer. |
| /// Fails if the scalar is a pointer. |
| pub fn to_target_isize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, i64> { |
| let b = self.to_int(cx.data_layout().pointer_size)?; |
| Ok(i64::try_from(b).unwrap()) |
| } |
| |
| #[inline] |
| pub fn to_f32(self) -> InterpResult<'tcx, Single> { |
| // Going through `u32` to check size and truncation. |
| Ok(Single::from_bits(self.to_u32()?.into())) |
| } |
| |
| #[inline] |
| pub fn to_f64(self) -> InterpResult<'tcx, Double> { |
| // Going through `u64` to check size and truncation. |
| Ok(Double::from_bits(self.to_u64()?.into())) |
| } |
| } |
| |
| /// Gets the bytes of a constant slice value. |
| pub fn get_slice_bytes<'tcx>(cx: &impl HasDataLayout, val: ConstValue<'tcx>) -> &'tcx [u8] { |
| if let ConstValue::Slice { data, start, end } = val { |
| let len = end - start; |
| data.inner() |
| .get_bytes_strip_provenance( |
| cx, |
| AllocRange { start: Size::from_bytes(start), size: Size::from_bytes(len) }, |
| ) |
| .unwrap_or_else(|err| bug!("const slice is invalid: {:?}", err)) |
| } else { |
| bug!("expected const slice, but found another const value"); |
| } |
| } |