diff options
Diffstat (limited to 'compiler/rustc_middle/src/ty/consts/int.rs')
| -rw-r--r-- | compiler/rustc_middle/src/ty/consts/int.rs | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/compiler/rustc_middle/src/ty/consts/int.rs b/compiler/rustc_middle/src/ty/consts/int.rs new file mode 100644 index 000000000..7436f0f6f --- /dev/null +++ b/compiler/rustc_middle/src/ty/consts/int.rs @@ -0,0 +1,483 @@ +use rustc_apfloat::ieee::{Double, Single}; +use rustc_apfloat::Float; +use rustc_serialize::{Decodable, Decoder, Encodable, Encoder}; +use rustc_target::abi::Size; +use std::convert::{TryFrom, TryInto}; +use std::fmt; +use std::num::NonZeroU8; + +use crate::ty::TyCtxt; + +#[derive(Copy, Clone)] +/// A type for representing any integer. Only used for printing. +pub struct ConstInt { + /// The "untyped" variant of `ConstInt`. + int: ScalarInt, + /// Whether the value is of a signed integer type. + signed: bool, + /// Whether the value is a `usize` or `isize` type. + is_ptr_sized_integral: bool, +} + +impl ConstInt { + pub fn new(int: ScalarInt, signed: bool, is_ptr_sized_integral: bool) -> Self { + Self { int, signed, is_ptr_sized_integral } + } +} + +impl std::fmt::Debug for ConstInt { + fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + let Self { int, signed, is_ptr_sized_integral } = *self; + let size = int.size().bytes(); + let raw = int.data; + if signed { + let bit_size = size * 8; + let min = 1u128 << (bit_size - 1); + let max = min - 1; + if raw == min { + match (size, is_ptr_sized_integral) { + (_, true) => write!(fmt, "isize::MIN"), + (1, _) => write!(fmt, "i8::MIN"), + (2, _) => write!(fmt, "i16::MIN"), + (4, _) => write!(fmt, "i32::MIN"), + (8, _) => write!(fmt, "i64::MIN"), + (16, _) => write!(fmt, "i128::MIN"), + _ => bug!("ConstInt 0x{:x} with size = {} and signed = {}", raw, size, signed), + } + } else if raw == max { + match (size, is_ptr_sized_integral) { + (_, true) => write!(fmt, "isize::MAX"), + (1, _) => write!(fmt, "i8::MAX"), + (2, _) => write!(fmt, "i16::MAX"), + (4, _) => write!(fmt, "i32::MAX"), + (8, _) => write!(fmt, "i64::MAX"), + (16, _) => write!(fmt, "i128::MAX"), + _ => bug!("ConstInt 0x{:x} with size = {} and signed = {}", raw, size, signed), + } + } else { + match size { + 1 => write!(fmt, "{}", raw as i8)?, + 2 => write!(fmt, "{}", raw as i16)?, + 4 => write!(fmt, "{}", raw as i32)?, + 8 => write!(fmt, "{}", raw as i64)?, + 16 => write!(fmt, "{}", raw as i128)?, + _ => bug!("ConstInt 0x{:x} with size = {} and signed = {}", raw, size, signed), + } + if fmt.alternate() { + match (size, is_ptr_sized_integral) { + (_, true) => write!(fmt, "_isize")?, + (1, _) => write!(fmt, "_i8")?, + (2, _) => write!(fmt, "_i16")?, + (4, _) => write!(fmt, "_i32")?, + (8, _) => write!(fmt, "_i64")?, + (16, _) => write!(fmt, "_i128")?, + _ => bug!(), + } + } + Ok(()) + } + } else { + let max = Size::from_bytes(size).truncate(u128::MAX); + if raw == max { + match (size, is_ptr_sized_integral) { + (_, true) => write!(fmt, "usize::MAX"), + (1, _) => write!(fmt, "u8::MAX"), + (2, _) => write!(fmt, "u16::MAX"), + (4, _) => write!(fmt, "u32::MAX"), + (8, _) => write!(fmt, "u64::MAX"), + (16, _) => write!(fmt, "u128::MAX"), + _ => bug!("ConstInt 0x{:x} with size = {} and signed = {}", raw, size, signed), + } + } else { + match size { + 1 => write!(fmt, "{}", raw as u8)?, + 2 => write!(fmt, "{}", raw as u16)?, + 4 => write!(fmt, "{}", raw as u32)?, + 8 => write!(fmt, "{}", raw as u64)?, + 16 => write!(fmt, "{}", raw as u128)?, + _ => bug!("ConstInt 0x{:x} with size = {} and signed = {}", raw, size, signed), + } + if fmt.alternate() { + match (size, is_ptr_sized_integral) { + (_, true) => write!(fmt, "_usize")?, + (1, _) => write!(fmt, "_u8")?, + (2, _) => write!(fmt, "_u16")?, + (4, _) => write!(fmt, "_u32")?, + (8, _) => write!(fmt, "_u64")?, + (16, _) => write!(fmt, "_u128")?, + _ => bug!(), + } + } + Ok(()) + } + } + } +} + +/// The raw bytes of a simple value. +/// +/// This is a packed struct in order to allow this type to be optimally embedded in enums +/// (like Scalar). +#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Hash)] +#[repr(packed)] +pub struct ScalarInt { + /// The first `size` bytes of `data` are the value. + /// Do not try to read less or more bytes than that. The remaining bytes must be 0. + data: u128, + size: NonZeroU8, +} + +// Cannot derive these, as the derives take references to the fields, and we +// can't take references to fields of packed structs. +impl<CTX> crate::ty::HashStable<CTX> for ScalarInt { + fn hash_stable(&self, hcx: &mut CTX, hasher: &mut crate::ty::StableHasher) { + // Using a block `{self.data}` here to force a copy instead of using `self.data` + // directly, because `hash_stable` takes `&self` and would thus borrow `self.data`. + // Since `Self` is a packed struct, that would create a possibly unaligned reference, + // which is UB. + { self.data }.hash_stable(hcx, hasher); + self.size.get().hash_stable(hcx, hasher); + } +} + +impl<S: Encoder> Encodable<S> for ScalarInt { + fn encode(&self, s: &mut S) { + s.emit_u128(self.data); + s.emit_u8(self.size.get()); + } +} + +impl<D: Decoder> Decodable<D> for ScalarInt { + fn decode(d: &mut D) -> ScalarInt { + ScalarInt { data: d.read_u128(), size: NonZeroU8::new(d.read_u8()).unwrap() } + } +} + +impl ScalarInt { + pub const TRUE: ScalarInt = ScalarInt { data: 1_u128, size: NonZeroU8::new(1).unwrap() }; + + pub const FALSE: ScalarInt = ScalarInt { data: 0_u128, size: NonZeroU8::new(1).unwrap() }; + + #[inline] + pub fn size(self) -> Size { + Size::from_bytes(self.size.get()) + } + + /// Make sure the `data` fits in `size`. + /// This is guaranteed by all constructors here, but having had this check saved us from + /// bugs many times in the past, so keeping it around is definitely worth it. + #[inline(always)] + fn check_data(self) { + // Using a block `{self.data}` here to force a copy instead of using `self.data` + // directly, because `debug_assert_eq` takes references to its arguments and formatting + // arguments and would thus borrow `self.data`. Since `Self` + // is a packed struct, that would create a possibly unaligned reference, which + // is UB. + debug_assert_eq!( + self.size().truncate(self.data), + { self.data }, + "Scalar value {:#x} exceeds size of {} bytes", + { self.data }, + self.size + ); + } + + #[inline] + pub fn null(size: Size) -> Self { + Self { data: 0, size: NonZeroU8::new(size.bytes() as u8).unwrap() } + } + + #[inline] + pub fn is_null(self) -> bool { + self.data == 0 + } + + #[inline] + pub fn try_from_uint(i: impl Into<u128>, size: Size) -> Option<Self> { + let data = i.into(); + if size.truncate(data) == data { + Some(Self { data, size: NonZeroU8::new(size.bytes() as u8).unwrap() }) + } else { + None + } + } + + #[inline] + pub fn try_from_int(i: impl Into<i128>, size: Size) -> Option<Self> { + let i = i.into(); + // `into` performed sign extension, we have to truncate + let truncated = size.truncate(i as u128); + if size.sign_extend(truncated) as i128 == i { + Some(Self { data: truncated, size: NonZeroU8::new(size.bytes() as u8).unwrap() }) + } else { + None + } + } + + #[inline] + pub fn assert_bits(self, target_size: Size) -> u128 { + self.to_bits(target_size).unwrap_or_else(|size| { + bug!("expected int of size {}, but got size {}", target_size.bytes(), size.bytes()) + }) + } + + #[inline] + pub fn to_bits(self, target_size: Size) -> Result<u128, Size> { + assert_ne!(target_size.bytes(), 0, "you should never look at the bits of a ZST"); + if target_size.bytes() == u64::from(self.size.get()) { + self.check_data(); + Ok(self.data) + } else { + Err(self.size()) + } + } + + #[inline] + pub fn try_to_machine_usize<'tcx>(&self, tcx: TyCtxt<'tcx>) -> Result<u64, Size> { + Ok(self.to_bits(tcx.data_layout.pointer_size)? as u64) + } + + /// Tries to convert the `ScalarInt` to an unsigned integer of the given size. + /// Fails if the size of the `ScalarInt` is unequal to `size` and returns the + /// `ScalarInt`s size in that case. + #[inline] + pub fn try_to_uint(self, size: Size) -> Result<u128, Size> { + self.to_bits(size) + } + + // Tries to convert the `ScalarInt` to `u8`. Fails if the `size` of the `ScalarInt` + // in not equal to `Size { raw: 1 }` and returns the `size` value of the `ScalarInt` in + // that case. + #[inline] + pub fn try_to_u8(self) -> Result<u8, Size> { + self.to_bits(Size::from_bits(8)).map(|v| u8::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u16`. Fails if the size of the `ScalarInt` + /// in not equal to `Size { raw: 2 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u16(self) -> Result<u16, Size> { + self.to_bits(Size::from_bits(16)).map(|v| u16::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u32`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 4 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u32(self) -> Result<u32, Size> { + self.to_bits(Size::from_bits(32)).map(|v| u32::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u64`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 8 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u64(self) -> Result<u64, Size> { + self.to_bits(Size::from_bits(64)).map(|v| u64::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to `u128`. Fails if the `size` of the `ScalarInt` + /// in not equal to `Size { raw: 16 }` and returns the `size` value of the `ScalarInt` in + /// that case. + #[inline] + pub fn try_to_u128(self) -> Result<u128, Size> { + self.to_bits(Size::from_bits(128)) + } + + /// Tries to convert the `ScalarInt` to a signed integer of the given size. + /// Fails if the size of the `ScalarInt` is unequal to `size` and returns the + /// `ScalarInt`s size in that case. + #[inline] + pub fn try_to_int(self, size: Size) -> Result<i128, Size> { + let b = self.to_bits(size)?; + Ok(size.sign_extend(b) as i128) + } + + /// Tries to convert the `ScalarInt` to i8. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 1 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i8(self) -> Result<i8, Size> { + self.try_to_int(Size::from_bits(8)).map(|v| i8::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i16. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 2 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i16(self) -> Result<i16, Size> { + self.try_to_int(Size::from_bits(16)).map(|v| i16::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i32. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 4 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i32(self) -> Result<i32, Size> { + self.try_to_int(Size::from_bits(32)).map(|v| i32::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i64. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 8 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i64(self) -> Result<i64, Size> { + self.try_to_int(Size::from_bits(64)).map(|v| i64::try_from(v).unwrap()) + } + + /// Tries to convert the `ScalarInt` to i128. + /// Fails if the size of the `ScalarInt` is unequal to `Size { raw: 16 }` + /// and returns the `ScalarInt`s size in that case. + pub fn try_to_i128(self) -> Result<i128, Size> { + self.try_to_int(Size::from_bits(128)).map(|v| i128::try_from(v).unwrap()) + } +} + +macro_rules! from { + ($($ty:ty),*) => { + $( + impl From<$ty> for ScalarInt { + #[inline] + fn from(u: $ty) -> Self { + Self { + data: u128::from(u), + size: NonZeroU8::new(std::mem::size_of::<$ty>() as u8).unwrap(), + } + } + } + )* + } +} + +macro_rules! try_from { + ($($ty:ty),*) => { + $( + impl TryFrom<ScalarInt> for $ty { + type Error = Size; + #[inline] + fn try_from(int: ScalarInt) -> Result<Self, Size> { + // The `unwrap` cannot fail because to_bits (if it succeeds) + // is guaranteed to return a value that fits into the size. + int.to_bits(Size::from_bytes(std::mem::size_of::<$ty>())) + .map(|u| u.try_into().unwrap()) + } + } + )* + } +} + +from!(u8, u16, u32, u64, u128, bool); +try_from!(u8, u16, u32, u64, u128); + +impl TryFrom<ScalarInt> for bool { + type Error = Size; + #[inline] + fn try_from(int: ScalarInt) -> Result<Self, Size> { + int.to_bits(Size::from_bytes(1)).and_then(|u| match u { + 0 => Ok(false), + 1 => Ok(true), + _ => Err(Size::from_bytes(1)), + }) + } +} + +impl From<char> for ScalarInt { + #[inline] + fn from(c: char) -> Self { + Self { data: c as u128, size: NonZeroU8::new(std::mem::size_of::<char>() as u8).unwrap() } + } +} + +/// Error returned when a conversion from ScalarInt to char fails. +#[derive(Debug)] +pub struct CharTryFromScalarInt; + +impl TryFrom<ScalarInt> for char { + type Error = CharTryFromScalarInt; + + #[inline] + fn try_from(int: ScalarInt) -> Result<Self, Self::Error> { + let Ok(bits) = int.to_bits(Size::from_bytes(std::mem::size_of::<char>())) else { + return Err(CharTryFromScalarInt); + }; + match char::from_u32(bits.try_into().unwrap()) { + Some(c) => Ok(c), + None => Err(CharTryFromScalarInt), + } + } +} + +impl From<Single> for ScalarInt { + #[inline] + fn from(f: Single) -> Self { + // We trust apfloat to give us properly truncated data. + Self { data: f.to_bits(), size: NonZeroU8::new((Single::BITS / 8) as u8).unwrap() } + } +} + +impl TryFrom<ScalarInt> for Single { + type Error = Size; + #[inline] + fn try_from(int: ScalarInt) -> Result<Self, Size> { + int.to_bits(Size::from_bytes(4)).map(Self::from_bits) + } +} + +impl From<Double> for ScalarInt { + #[inline] + fn from(f: Double) -> Self { + // We trust apfloat to give us properly truncated data. + Self { data: f.to_bits(), size: NonZeroU8::new((Double::BITS / 8) as u8).unwrap() } + } +} + +impl TryFrom<ScalarInt> for Double { + type Error = Size; + #[inline] + fn try_from(int: ScalarInt) -> Result<Self, Size> { + int.to_bits(Size::from_bytes(8)).map(Self::from_bits) + } +} + +impl fmt::Debug for ScalarInt { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + // Dispatch to LowerHex below. + write!(f, "0x{:x}", self) + } +} + +impl fmt::LowerHex for ScalarInt { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.check_data(); + if f.alternate() { + // Like regular ints, alternate flag adds leading `0x`. + write!(f, "0x")?; + } + // Format as hex number wide enough to fit any value of the given `size`. + // So data=20, size=1 will be "0x14", but with size=4 it'll be "0x00000014". + // Using a block `{self.data}` here to force a copy instead of using `self.data` + // directly, because `write!` takes references to its formatting arguments and + // would thus borrow `self.data`. Since `Self` + // is a packed struct, that would create a possibly unaligned reference, which + // is UB. + write!(f, "{:01$x}", { self.data }, self.size.get() as usize * 2) + } +} + +impl fmt::UpperHex for ScalarInt { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.check_data(); + // Format as hex number wide enough to fit any value of the given `size`. + // So data=20, size=1 will be "0x14", but with size=4 it'll be "0x00000014". + // Using a block `{self.data}` here to force a copy instead of using `self.data` + // directly, because `write!` takes references to its formatting arguments and + // would thus borrow `self.data`. Since `Self` + // is a packed struct, that would create a possibly unaligned reference, which + // is UB. + write!(f, "{:01$X}", { self.data }, self.size.get() as usize * 2) + } +} + +impl fmt::Display for ScalarInt { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.check_data(); + write!(f, "{}", { self.data }) + } +} |