2 ieee::{Double, Single},
5 use rustc_macros::HashStable;
9 layout::{HasDataLayout, Size},
13 use super::{sign_extend, truncate, AllocId, Allocation, InterpResult, Pointer, PointerArithmetic};
15 /// Represents the result of a raw const operation, pre-validation.
16 #[derive(Clone, HashStable)]
17 pub struct RawConst<'tcx> {
18 // the value lives here, at offset 0, and that allocation definitely is a `AllocKind::Memory`
19 // (so you can use `AllocMap::unwrap_memory`).
20 pub alloc_id: AllocId,
24 /// Represents a constant value in Rust. `Scalar` and `Slice` are optimizations for
25 /// array length computations, enum discriminants and the pattern matching logic.
39 pub enum ConstValue<'tcx> {
40 /// Used only for types with `layout::abi::Scalar` ABI and ZSTs.
42 /// Not using the enum `Value` to encode that this must not be `Undef`.
45 /// Used only for `&[u8]` and `&str`
46 Slice { data: &'tcx Allocation, start: usize, end: usize },
48 /// A value not represented/representable by `Scalar` or `Slice`
50 /// The backing memory of the value, may contain more memory than needed for just the value
51 /// in order to share `Allocation`s between values
52 alloc: &'tcx Allocation,
53 /// Offset into `alloc`
58 #[cfg(target_arch = "x86_64")]
59 static_assert_size!(ConstValue<'_>, 32);
61 impl<'tcx> ConstValue<'tcx> {
63 pub fn try_to_scalar(&self) -> Option<Scalar> {
65 ConstValue::ByRef { .. } | ConstValue::Slice { .. } => None,
66 ConstValue::Scalar(val) => Some(val),
70 pub fn try_to_bits(&self, size: Size) -> Option<u128> {
71 self.try_to_scalar()?.to_bits(size).ok()
74 pub fn try_to_bits_for_ty(
77 param_env: ParamEnv<'tcx>,
80 let size = tcx.layout_of(param_env.with_reveal_all().and(ty)).ok()?.size;
81 self.try_to_bits(size)
84 pub fn from_bool(b: bool) -> Self {
85 ConstValue::Scalar(Scalar::from_bool(b))
88 pub fn from_u64(i: u64) -> Self {
89 ConstValue::Scalar(Scalar::from_u64(i))
92 pub fn from_machine_usize(i: u64, cx: &impl HasDataLayout) -> Self {
93 ConstValue::Scalar(Scalar::from_machine_usize(i, cx))
97 /// A `Scalar` represents an immediate, primitive value existing outside of a
98 /// `memory::Allocation`. It is in many ways like a small chunk of a `Allocation`, up to 8 bytes in
99 /// size. Like a range of bytes in an `Allocation`, a `Scalar` can either represent the raw bytes
100 /// of a simple value or a pointer into another `Allocation`
113 pub enum Scalar<Tag = (), Id = AllocId> {
114 /// The raw bytes of a simple value.
116 /// The first `size` bytes of `data` are the value.
117 /// Do not try to read less or more bytes than that. The remaining bytes must be 0.
122 /// A pointer into an `Allocation`. An `Allocation` in the `memory` module has a list of
123 /// relocations, but a `Scalar` is only large enough to contain one, so we just represent the
124 /// relocation and its associated offset together as a `Pointer` here.
125 Ptr(Pointer<Tag, Id>),
128 #[cfg(target_arch = "x86_64")]
129 static_assert_size!(Scalar, 24);
131 impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for Scalar<Tag, Id> {
132 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
134 Scalar::Ptr(ptr) => write!(f, "{:?}", ptr),
135 &Scalar::Raw { data, size } => {
136 Scalar::check_data(data, size);
140 // Format as hex number wide enough to fit any value of the given `size`.
141 // So data=20, size=1 will be "0x14", but with size=4 it'll be "0x00000014".
142 write!(f, "0x{:>0width$x}", data, width = (size * 2) as usize)
149 impl<Tag> fmt::Display for Scalar<Tag> {
150 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
152 Scalar::Ptr(_) => write!(f, "a pointer"),
153 Scalar::Raw { data, .. } => write!(f, "{}", data),
158 impl<Tag> From<Single> for Scalar<Tag> {
160 fn from(f: Single) -> Self {
165 impl<Tag> From<Double> for Scalar<Tag> {
167 fn from(f: Double) -> Self {
173 /// Make sure the `data` fits in `size`.
174 /// This is guaranteed by all constructors here, but since the enum variants are public,
175 /// it could still be violated (even though no code outside this file should
176 /// construct `Scalar`s).
178 fn check_data(data: u128, size: u8) {
180 truncate(data, Size::from_bytes(size as u64)),
182 "Scalar value {:#x} exceeds size of {} bytes",
188 /// Tag this scalar with `new_tag` if it is a pointer, leave it unchanged otherwise.
190 /// Used by `MemPlace::replace_tag`.
192 pub fn with_tag<Tag>(self, new_tag: Tag) -> Scalar<Tag> {
194 Scalar::Ptr(ptr) => Scalar::Ptr(ptr.with_tag(new_tag)),
195 Scalar::Raw { data, size } => Scalar::Raw { data, size },
200 impl<'tcx, Tag> Scalar<Tag> {
201 /// Erase the tag from the scalar, if any.
203 /// Used by error reporting code to avoid having the error type depend on `Tag`.
205 pub fn erase_tag(self) -> Scalar {
207 Scalar::Ptr(ptr) => Scalar::Ptr(ptr.erase_tag()),
208 Scalar::Raw { data, size } => Scalar::Raw { data, size },
213 pub fn ptr_null(cx: &impl HasDataLayout) -> Self {
214 Scalar::Raw { data: 0, size: cx.data_layout().pointer_size.bytes() as u8 }
218 pub fn zst() -> Self {
219 Scalar::Raw { data: 0, size: 0 }
223 pub fn ptr_offset(self, i: Size, cx: &impl HasDataLayout) -> InterpResult<'tcx, Self> {
224 let dl = cx.data_layout();
226 Scalar::Raw { data, size } => {
227 assert_eq!(size as u64, dl.pointer_size.bytes());
228 Ok(Scalar::Raw { data: dl.offset(data as u64, i.bytes())? as u128, size })
230 Scalar::Ptr(ptr) => ptr.offset(i, dl).map(Scalar::Ptr),
235 pub fn ptr_wrapping_offset(self, i: Size, cx: &impl HasDataLayout) -> Self {
236 let dl = cx.data_layout();
238 Scalar::Raw { data, size } => {
239 assert_eq!(size as u64, dl.pointer_size.bytes());
240 Scalar::Raw { data: dl.overflowing_offset(data as u64, i.bytes()).0 as u128, size }
242 Scalar::Ptr(ptr) => Scalar::Ptr(ptr.wrapping_offset(i, dl)),
247 pub fn ptr_signed_offset(self, i: i64, cx: &impl HasDataLayout) -> InterpResult<'tcx, Self> {
248 let dl = cx.data_layout();
250 Scalar::Raw { data, size } => {
251 assert_eq!(size as u64, dl.pointer_size().bytes());
252 Ok(Scalar::Raw { data: dl.signed_offset(data as u64, i)? as u128, size })
254 Scalar::Ptr(ptr) => ptr.signed_offset(i, dl).map(Scalar::Ptr),
259 pub fn ptr_wrapping_signed_offset(self, i: i64, cx: &impl HasDataLayout) -> Self {
260 let dl = cx.data_layout();
262 Scalar::Raw { data, size } => {
263 assert_eq!(size as u64, dl.pointer_size.bytes());
265 data: dl.overflowing_signed_offset(data as u64, i128::from(i)).0 as u128,
269 Scalar::Ptr(ptr) => Scalar::Ptr(ptr.wrapping_signed_offset(i, dl)),
274 pub fn from_bool(b: bool) -> Self {
275 Scalar::Raw { data: b as u128, size: 1 }
279 pub fn from_char(c: char) -> Self {
280 Scalar::Raw { data: c as u128, size: 4 }
284 pub fn try_from_uint(i: impl Into<u128>, size: Size) -> Option<Self> {
286 if truncate(i, size) == i {
287 Some(Scalar::Raw { data: i, size: size.bytes() as u8 })
294 pub fn from_uint(i: impl Into<u128>, size: Size) -> Self {
296 Self::try_from_uint(i, size)
297 .unwrap_or_else(|| bug!("Unsigned value {:#x} does not fit in {} bits", i, size.bits()))
301 pub fn from_u8(i: u8) -> Self {
302 Scalar::Raw { data: i as u128, size: 1 }
306 pub fn from_u16(i: u16) -> Self {
307 Scalar::Raw { data: i as u128, size: 2 }
311 pub fn from_u32(i: u32) -> Self {
312 Scalar::Raw { data: i as u128, size: 4 }
316 pub fn from_u64(i: u64) -> Self {
317 Scalar::Raw { data: i as u128, size: 8 }
321 pub fn from_machine_usize(i: u64, cx: &impl HasDataLayout) -> Self {
322 Self::from_uint(i, cx.data_layout().pointer_size)
326 pub fn try_from_int(i: impl Into<i128>, size: Size) -> Option<Self> {
328 // `into` performed sign extension, we have to truncate
329 let truncated = truncate(i as u128, size);
330 if sign_extend(truncated, size) as i128 == i {
331 Some(Scalar::Raw { data: truncated, size: size.bytes() as u8 })
338 pub fn from_int(i: impl Into<i128>, size: Size) -> Self {
340 Self::try_from_int(i, size)
341 .unwrap_or_else(|| bug!("Signed value {:#x} does not fit in {} bits", i, size.bits()))
345 pub fn from_machine_isize(i: i64, cx: &impl HasDataLayout) -> Self {
346 Self::from_int(i, cx.data_layout().pointer_size)
350 pub fn from_f32(f: Single) -> Self {
351 // We trust apfloat to give us properly truncated data.
352 Scalar::Raw { data: f.to_bits(), size: 4 }
356 pub fn from_f64(f: Double) -> Self {
357 // We trust apfloat to give us properly truncated data.
358 Scalar::Raw { data: f.to_bits(), size: 8 }
361 /// This is very rarely the method you want! You should dispatch on the type
362 /// and use `force_bits`/`assert_bits`/`force_ptr`/`assert_ptr`.
363 /// This method only exists for the benefit of low-level memory operations
364 /// as well as the implementation of the `force_*` methods.
366 pub fn to_bits_or_ptr(
369 cx: &impl HasDataLayout,
370 ) -> Result<u128, Pointer<Tag>> {
372 Scalar::Raw { data, size } => {
373 assert_eq!(target_size.bytes(), size as u64);
374 assert_ne!(size, 0, "you should never look at the bits of a ZST");
375 Scalar::check_data(data, size);
378 Scalar::Ptr(ptr) => {
379 assert_eq!(target_size, cx.data_layout().pointer_size);
386 pub fn check_raw(data: u128, size: u8, target_size: Size) {
387 assert_eq!(target_size.bytes(), size as u64);
388 assert_ne!(size, 0, "you should never look at the bits of a ZST");
389 Scalar::check_data(data, size);
392 /// Do not call this method! Use either `assert_bits` or `force_bits`.
394 pub fn to_bits(self, target_size: Size) -> InterpResult<'tcx, u128> {
396 Scalar::Raw { data, size } => {
397 Self::check_raw(data, size, target_size);
400 Scalar::Ptr(_) => throw_unsup!(ReadPointerAsBytes),
405 pub fn assert_bits(self, target_size: Size) -> u128 {
406 self.to_bits(target_size).expect("expected Raw bits but got a Pointer")
410 pub fn assert_ptr(self) -> Pointer<Tag> {
413 Scalar::Raw { .. } => bug!("expected a Pointer but got Raw bits")
417 /// Do not call this method! Dispatch based on the type instead.
419 pub fn is_bits(self) -> bool {
421 Scalar::Raw { .. } => true,
426 /// Do not call this method! Dispatch based on the type instead.
428 pub fn is_ptr(self) -> bool {
430 Scalar::Ptr(_) => true,
435 pub fn to_bool(self) -> InterpResult<'tcx, bool> {
437 Scalar::Raw { data: 0, size: 1 } => Ok(false),
438 Scalar::Raw { data: 1, size: 1 } => Ok(true),
439 _ => throw_unsup!(InvalidBool),
443 pub fn to_char(self) -> InterpResult<'tcx, char> {
444 let val = self.to_u32()?;
445 match ::std::char::from_u32(val) {
447 None => throw_unsup!(InvalidChar(val as u128)),
452 fn to_unsigned_with_bit_width(self, bits: u64) -> InterpResult<'static, u128> {
453 let sz = Size::from_bits(bits);
457 /// Converts the scalar to produce an `u8`. Fails if the scalar is a pointer.
458 pub fn to_u8(self) -> InterpResult<'static, u8> {
459 self.to_unsigned_with_bit_width(8).map(|v| v as u8)
462 /// Converts the scalar to produce an `u16`. Fails if the scalar is a pointer.
463 pub fn to_u16(self) -> InterpResult<'static, u16> {
464 self.to_unsigned_with_bit_width(16).map(|v| v as u16)
467 /// Converts the scalar to produce an `u32`. Fails if the scalar is a pointer.
468 pub fn to_u32(self) -> InterpResult<'static, u32> {
469 self.to_unsigned_with_bit_width(32).map(|v| v as u32)
472 /// Converts the scalar to produce an `u64`. Fails if the scalar is a pointer.
473 pub fn to_u64(self) -> InterpResult<'static, u64> {
474 self.to_unsigned_with_bit_width(64).map(|v| v as u64)
477 pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'static, u64> {
478 let b = self.to_bits(cx.data_layout().pointer_size)?;
483 fn to_signed_with_bit_width(self, bits: u64) -> InterpResult<'static, i128> {
484 let sz = Size::from_bits(bits);
485 let b = self.to_bits(sz)?;
486 Ok(sign_extend(b, sz) as i128)
489 /// Converts the scalar to produce an `i8`. Fails if the scalar is a pointer.
490 pub fn to_i8(self) -> InterpResult<'static, i8> {
491 self.to_signed_with_bit_width(8).map(|v| v as i8)
494 /// Converts the scalar to produce an `i16`. Fails if the scalar is a pointer.
495 pub fn to_i16(self) -> InterpResult<'static, i16> {
496 self.to_signed_with_bit_width(16).map(|v| v as i16)
499 /// Converts the scalar to produce an `i32`. Fails if the scalar is a pointer.
500 pub fn to_i32(self) -> InterpResult<'static, i32> {
501 self.to_signed_with_bit_width(32).map(|v| v as i32)
504 /// Converts the scalar to produce an `i64`. Fails if the scalar is a pointer.
505 pub fn to_i64(self) -> InterpResult<'static, i64> {
506 self.to_signed_with_bit_width(64).map(|v| v as i64)
509 pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'static, i64> {
510 let sz = cx.data_layout().pointer_size;
511 let b = self.to_bits(sz)?;
512 let b = sign_extend(b, sz) as i128;
517 pub fn to_f32(self) -> InterpResult<'static, Single> {
518 // Going through `u32` to check size and truncation.
519 Ok(Single::from_bits(self.to_u32()? as u128))
523 pub fn to_f64(self) -> InterpResult<'static, Double> {
524 // Going through `u64` to check size and truncation.
525 Ok(Double::from_bits(self.to_u64()? as u128))
529 impl<Tag> From<Pointer<Tag>> for Scalar<Tag> {
531 fn from(ptr: Pointer<Tag>) -> Self {
536 #[derive(Clone, Copy, Eq, PartialEq, RustcEncodable, RustcDecodable, HashStable, Hash)]
537 pub enum ScalarMaybeUndef<Tag = (), Id = AllocId> {
538 Scalar(Scalar<Tag, Id>),
542 impl<Tag> From<Scalar<Tag>> for ScalarMaybeUndef<Tag> {
544 fn from(s: Scalar<Tag>) -> Self {
545 ScalarMaybeUndef::Scalar(s)
549 impl<Tag> From<Pointer<Tag>> for ScalarMaybeUndef<Tag> {
551 fn from(s: Pointer<Tag>) -> Self {
552 ScalarMaybeUndef::Scalar(s.into())
556 impl<Tag: fmt::Debug, Id: fmt::Debug> fmt::Debug for ScalarMaybeUndef<Tag, Id> {
557 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
559 ScalarMaybeUndef::Undef => write!(f, "Undef"),
560 ScalarMaybeUndef::Scalar(s) => write!(f, "{:?}", s),
565 impl<Tag> fmt::Display for ScalarMaybeUndef<Tag> {
566 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
568 ScalarMaybeUndef::Undef => write!(f, "uninitialized bytes"),
569 ScalarMaybeUndef::Scalar(s) => write!(f, "{}", s),
574 impl<'tcx, Tag> ScalarMaybeUndef<Tag> {
575 /// Erase the tag from the scalar, if any.
577 /// Used by error reporting code to avoid having the error type depend on `Tag`.
579 pub fn erase_tag(self) -> ScalarMaybeUndef {
581 ScalarMaybeUndef::Scalar(s) => ScalarMaybeUndef::Scalar(s.erase_tag()),
582 ScalarMaybeUndef::Undef => ScalarMaybeUndef::Undef,
587 pub fn not_undef(self) -> InterpResult<'static, Scalar<Tag>> {
589 ScalarMaybeUndef::Scalar(scalar) => Ok(scalar),
590 ScalarMaybeUndef::Undef => throw_unsup!(ReadUndefBytes(Size::ZERO)),
594 /// Do not call this method! Use either `assert_bits` or `force_bits`.
596 pub fn to_bits(self, target_size: Size) -> InterpResult<'tcx, u128> {
597 self.not_undef()?.to_bits(target_size)
601 pub fn to_bool(self) -> InterpResult<'tcx, bool> {
602 self.not_undef()?.to_bool()
606 pub fn to_char(self) -> InterpResult<'tcx, char> {
607 self.not_undef()?.to_char()
611 pub fn to_f32(self) -> InterpResult<'tcx, Single> {
612 self.not_undef()?.to_f32()
616 pub fn to_f64(self) -> InterpResult<'tcx, Double> {
617 self.not_undef()?.to_f64()
621 pub fn to_u8(self) -> InterpResult<'tcx, u8> {
622 self.not_undef()?.to_u8()
626 pub fn to_u32(self) -> InterpResult<'tcx, u32> {
627 self.not_undef()?.to_u32()
631 pub fn to_u64(self) -> InterpResult<'tcx, u64> {
632 self.not_undef()?.to_u64()
636 pub fn to_machine_usize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, u64> {
637 self.not_undef()?.to_machine_usize(cx)
641 pub fn to_i8(self) -> InterpResult<'tcx, i8> {
642 self.not_undef()?.to_i8()
646 pub fn to_i32(self) -> InterpResult<'tcx, i32> {
647 self.not_undef()?.to_i32()
651 pub fn to_i64(self) -> InterpResult<'tcx, i64> {
652 self.not_undef()?.to_i64()
656 pub fn to_machine_isize(self, cx: &impl HasDataLayout) -> InterpResult<'tcx, i64> {
657 self.not_undef()?.to_machine_isize(cx)
661 /// Gets the bytes of a constant slice value.
662 pub fn get_slice_bytes<'tcx>(cx: &impl HasDataLayout, val: ConstValue<'tcx>) -> &'tcx [u8] {
663 if let ConstValue::Slice { data, start, end } = val {
664 let len = end - start;
667 // invent a pointer, only the offset is relevant anyway
668 Pointer::new(AllocId(0), Size::from_bytes(start as u64)),
669 Size::from_bytes(len as u64),
671 .unwrap_or_else(|err| bug!("const slice is invalid: {:?}", err))
673 bug!("expected const slice, but found another const value");