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//! Intrinsics and other functions that the interpreter executes without
//! looking at their MIR. Intrinsics/functions supported here are shared by CTFE
//! and miri.
use std::assert_matches::assert_matches;
use rustc_abi::{FieldIdx, HasDataLayout, Size};
use rustc_apfloat::ieee::{Double, Half, Quad, Single};
use rustc_middle::mir::interpret::{CTFE_ALLOC_SALT, read_target_uint, write_target_uint};
use rustc_middle::mir::{self, BinOp, ConstValue, NonDivergingIntrinsic};
use rustc_middle::ty::layout::TyAndLayout;
use rustc_middle::ty::{Ty, TyCtxt};
use rustc_middle::{bug, ty};
use rustc_span::{Symbol, sym};
use tracing::trace;
use super::memory::MemoryKind;
use super::util::ensure_monomorphic_enough;
use super::{
AllocId, CheckInAllocMsg, ImmTy, InterpCx, InterpResult, Machine, OpTy, PlaceTy, Pointer,
PointerArithmetic, Provenance, Scalar, err_ub_custom, err_unsup_format, interp_ok, throw_inval,
throw_ub_custom, throw_ub_format,
};
use crate::fluent_generated as fluent;
/// Directly returns an `Allocation` containing an absolute path representation of the given type.
pub(crate) fn alloc_type_name<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> (AllocId, u64) {
let path = crate::util::type_name(tcx, ty);
let bytes = path.into_bytes();
let len = bytes.len().try_into().unwrap();
(tcx.allocate_bytes_dedup(bytes, CTFE_ALLOC_SALT), len)
}
impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
/// Generates a value of `TypeId` for `ty` in-place.
fn write_type_id(
&mut self,
ty: Ty<'tcx>,
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()> {
let tcx = self.tcx;
let type_id_hash = tcx.type_id_hash(ty).as_u128();
let op = self.const_val_to_op(
ConstValue::Scalar(Scalar::from_u128(type_id_hash)),
tcx.types.u128,
None,
)?;
self.copy_op_allow_transmute(&op, dest)?;
// Give the each pointer-sized chunk provenance that knows about the type id.
// Here we rely on `TypeId` being a newtype around an array of pointers, so we
// first project to its only field and then the array elements.
let alloc_id = tcx.reserve_and_set_type_id_alloc(ty);
let arr = self.project_field(dest, FieldIdx::ZERO)?;
let mut elem_iter = self.project_array_fields(&arr)?;
while let Some((_, elem)) = elem_iter.next(self)? {
// Decorate this part of the hash with provenance; leave the integer part unchanged.
let hash_fragment = self.read_scalar(&elem)?.to_target_usize(&tcx)?;
let ptr = Pointer::new(alloc_id.into(), Size::from_bytes(hash_fragment));
let ptr = self.global_root_pointer(ptr)?;
let val = Scalar::from_pointer(ptr, &tcx);
self.write_scalar(val, &elem)?;
}
interp_ok(())
}
/// Read a value of type `TypeId`, returning the type it represents.
pub(crate) fn read_type_id(
&self,
op: &OpTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, Ty<'tcx>> {
// `TypeId` is a newtype around an array of pointers. All pointers must have the same
// provenance, and that provenance represents the type.
let ptr_size = self.pointer_size().bytes_usize();
let arr = self.project_field(op, FieldIdx::ZERO)?;
let mut ty_and_hash = None;
let mut elem_iter = self.project_array_fields(&arr)?;
while let Some((idx, elem)) = elem_iter.next(self)? {
let elem = self.read_pointer(&elem)?;
let (elem_ty, elem_hash) = self.get_ptr_type_id(elem)?;
// If this is the first element, remember the type and its hash.
// If this is not the first element, ensure it is consistent with the previous ones.
let full_hash = match ty_and_hash {
None => {
let hash = self.tcx.type_id_hash(elem_ty).as_u128();
let mut hash_bytes = [0u8; 16];
write_target_uint(self.data_layout().endian, &mut hash_bytes, hash).unwrap();
ty_and_hash = Some((elem_ty, hash_bytes));
hash_bytes
}
Some((ty, hash_bytes)) => {
if ty != elem_ty {
throw_ub_format!(
"invalid `TypeId` value: not all bytes carry the same type id metadata"
);
}
hash_bytes
}
};
// Ensure the elem_hash matches the corresponding part of the full hash.
let hash_frag = &full_hash[(idx as usize) * ptr_size..][..ptr_size];
if read_target_uint(self.data_layout().endian, hash_frag).unwrap() != elem_hash.into() {
throw_ub_format!(
"invalid `TypeId` value: the hash does not match the type id metadata"
);
}
}
interp_ok(ty_and_hash.unwrap().0)
}
/// Returns `true` if emulation happened.
/// Here we implement the intrinsics that are common to all Miri instances; individual machines can add their own
/// intrinsic handling.
pub fn eval_intrinsic(
&mut self,
instance: ty::Instance<'tcx>,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
ret: Option<mir::BasicBlock>,
) -> InterpResult<'tcx, bool> {
let instance_args = instance.args;
let intrinsic_name = self.tcx.item_name(instance.def_id());
let tcx = self.tcx.tcx;
match intrinsic_name {
sym::type_name => {
let tp_ty = instance.args.type_at(0);
ensure_monomorphic_enough(tcx, tp_ty)?;
let (alloc_id, meta) = alloc_type_name(tcx, tp_ty);
let val = ConstValue::Slice { alloc_id, meta };
let val = self.const_val_to_op(val, dest.layout.ty, Some(dest.layout))?;
self.copy_op(&val, dest)?;
}
sym::needs_drop => {
let tp_ty = instance.args.type_at(0);
ensure_monomorphic_enough(tcx, tp_ty)?;
let val = ConstValue::from_bool(tp_ty.needs_drop(tcx, self.typing_env));
let val = self.const_val_to_op(val, tcx.types.bool, Some(dest.layout))?;
self.copy_op(&val, dest)?;
}
sym::type_id => {
let tp_ty = instance.args.type_at(0);
ensure_monomorphic_enough(tcx, tp_ty)?;
self.write_type_id(tp_ty, dest)?;
}
sym::type_id_eq => {
let a_ty = self.read_type_id(&args[0])?;
let b_ty = self.read_type_id(&args[1])?;
self.write_scalar(Scalar::from_bool(a_ty == b_ty), dest)?;
}
sym::variant_count => {
let tp_ty = instance.args.type_at(0);
let ty = match tp_ty.kind() {
// Pattern types have the same number of variants as their base type.
// Even if we restrict e.g. which variants are valid, the variants are essentially just uninhabited.
// And `Result<(), !>` still has two variants according to `variant_count`.
ty::Pat(base, _) => *base,
_ => tp_ty,
};
let val = match ty.kind() {
// Correctly handles non-monomorphic calls, so there is no need for ensure_monomorphic_enough.
ty::Adt(adt, _) => {
ConstValue::from_target_usize(adt.variants().len() as u64, &tcx)
}
ty::Alias(..) | ty::Param(_) | ty::Placeholder(_) | ty::Infer(_) => {
throw_inval!(TooGeneric)
}
ty::Pat(..) => unreachable!(),
ty::Bound(_, _) => bug!("bound ty during ctfe"),
ty::Bool
| ty::Char
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_)
| ty::Foreign(_)
| ty::Str
| ty::Array(_, _)
| ty::Slice(_)
| ty::RawPtr(_, _)
| ty::Ref(_, _, _)
| ty::FnDef(_, _)
| ty::FnPtr(..)
| ty::Dynamic(_, _, _)
| ty::Closure(_, _)
| ty::CoroutineClosure(_, _)
| ty::Coroutine(_, _)
| ty::CoroutineWitness(..)
| ty::UnsafeBinder(_)
| ty::Never
| ty::Tuple(_)
| ty::Error(_) => ConstValue::from_target_usize(0u64, &tcx),
};
let val = self.const_val_to_op(val, dest.layout.ty, Some(dest.layout))?;
self.copy_op(&val, dest)?;
}
sym::caller_location => {
let span = self.find_closest_untracked_caller_location();
let val = self.tcx.span_as_caller_location(span);
let val =
self.const_val_to_op(val, self.tcx.caller_location_ty(), Some(dest.layout))?;
self.copy_op(&val, dest)?;
}
sym::align_of_val | sym::size_of_val => {
// Avoid `deref_pointer` -- this is not a deref, the ptr does not have to be
// dereferenceable!
let place = self.ref_to_mplace(&self.read_immediate(&args[0])?)?;
let (size, align) = self
.size_and_align_of_val(&place)?
.ok_or_else(|| err_unsup_format!("`extern type` does not have known layout"))?;
let result = match intrinsic_name {
sym::align_of_val => align.bytes(),
sym::size_of_val => size.bytes(),
_ => bug!(),
};
self.write_scalar(Scalar::from_target_usize(result, self), dest)?;
}
sym::fadd_algebraic
| sym::fsub_algebraic
| sym::fmul_algebraic
| sym::fdiv_algebraic
| sym::frem_algebraic => {
let a = self.read_immediate(&args[0])?;
let b = self.read_immediate(&args[1])?;
let op = match intrinsic_name {
sym::fadd_algebraic => BinOp::Add,
sym::fsub_algebraic => BinOp::Sub,
sym::fmul_algebraic => BinOp::Mul,
sym::fdiv_algebraic => BinOp::Div,
sym::frem_algebraic => BinOp::Rem,
_ => bug!(),
};
let res = self.binary_op(op, &a, &b)?;
// `binary_op` already called `generate_nan` if needed.
let res = M::apply_float_nondet(self, res)?;
self.write_immediate(*res, dest)?;
}
sym::ctpop
| sym::cttz
| sym::cttz_nonzero
| sym::ctlz
| sym::ctlz_nonzero
| sym::bswap
| sym::bitreverse => {
let ty = instance_args.type_at(0);
let layout = self.layout_of(ty)?;
let val = self.read_scalar(&args[0])?;
let out_val = self.numeric_intrinsic(intrinsic_name, val, layout, dest.layout)?;
self.write_scalar(out_val, dest)?;
}
sym::saturating_add | sym::saturating_sub => {
let l = self.read_immediate(&args[0])?;
let r = self.read_immediate(&args[1])?;
let val = self.saturating_arith(
if intrinsic_name == sym::saturating_add { BinOp::Add } else { BinOp::Sub },
&l,
&r,
)?;
self.write_scalar(val, dest)?;
}
sym::discriminant_value => {
let place = self.deref_pointer(&args[0])?;
let variant = self.read_discriminant(&place)?;
let discr = self.discriminant_for_variant(place.layout.ty, variant)?;
self.write_immediate(*discr, dest)?;
}
sym::exact_div => {
let l = self.read_immediate(&args[0])?;
let r = self.read_immediate(&args[1])?;
self.exact_div(&l, &r, dest)?;
}
sym::rotate_left | sym::rotate_right => {
// rotate_left: (X << (S % BW)) | (X >> ((BW - S) % BW))
// rotate_right: (X << ((BW - S) % BW)) | (X >> (S % BW))
let layout_val = self.layout_of(instance_args.type_at(0))?;
let val = self.read_scalar(&args[0])?;
let val_bits = val.to_bits(layout_val.size)?; // sign is ignored here
let layout_raw_shift = self.layout_of(self.tcx.types.u32)?;
let raw_shift = self.read_scalar(&args[1])?;
let raw_shift_bits = raw_shift.to_bits(layout_raw_shift.size)?;
let width_bits = u128::from(layout_val.size.bits());
let shift_bits = raw_shift_bits % width_bits;
let inv_shift_bits = (width_bits - shift_bits) % width_bits;
let result_bits = if intrinsic_name == sym::rotate_left {
(val_bits << shift_bits) | (val_bits >> inv_shift_bits)
} else {
(val_bits >> shift_bits) | (val_bits << inv_shift_bits)
};
let truncated_bits = layout_val.size.truncate(result_bits);
let result = Scalar::from_uint(truncated_bits, layout_val.size);
self.write_scalar(result, dest)?;
}
sym::copy => {
self.copy_intrinsic(&args[0], &args[1], &args[2], /*nonoverlapping*/ false)?;
}
sym::write_bytes => {
self.write_bytes_intrinsic(&args[0], &args[1], &args[2], "write_bytes")?;
}
sym::compare_bytes => {
let result = self.compare_bytes_intrinsic(&args[0], &args[1], &args[2])?;
self.write_scalar(result, dest)?;
}
sym::arith_offset => {
let ptr = self.read_pointer(&args[0])?;
let offset_count = self.read_target_isize(&args[1])?;
let pointee_ty = instance_args.type_at(0);
let pointee_size = i64::try_from(self.layout_of(pointee_ty)?.size.bytes()).unwrap();
let offset_bytes = offset_count.wrapping_mul(pointee_size);
let offset_ptr = ptr.wrapping_signed_offset(offset_bytes, self);
self.write_pointer(offset_ptr, dest)?;
}
sym::ptr_offset_from | sym::ptr_offset_from_unsigned => {
let a = self.read_pointer(&args[0])?;
let b = self.read_pointer(&args[1])?;
let usize_layout = self.layout_of(self.tcx.types.usize)?;
let isize_layout = self.layout_of(self.tcx.types.isize)?;
// Get offsets for both that are at least relative to the same base.
// With `OFFSET_IS_ADDR` this is trivial; without it we need either
// two integers or two pointers into the same allocation.
let (a_offset, b_offset, is_addr) = if M::Provenance::OFFSET_IS_ADDR {
(a.addr().bytes(), b.addr().bytes(), /*is_addr*/ true)
} else {
match (self.ptr_try_get_alloc_id(a, 0), self.ptr_try_get_alloc_id(b, 0)) {
(Err(a), Err(b)) => {
// Neither pointer points to an allocation, so they are both absolute.
(a, b, /*is_addr*/ true)
}
(Ok((a_alloc_id, a_offset, _)), Ok((b_alloc_id, b_offset, _)))
if a_alloc_id == b_alloc_id =>
{
// Found allocation for both, and it's the same.
// Use these offsets for distance calculation.
(a_offset.bytes(), b_offset.bytes(), /*is_addr*/ false)
}
_ => {
// Not into the same allocation -- this is UB.
throw_ub_custom!(
fluent::const_eval_offset_from_different_allocations,
name = intrinsic_name,
);
}
}
};
// Compute distance: a - b.
let dist = {
// Addresses are unsigned, so this is a `usize` computation. We have to do the
// overflow check separately anyway.
let (val, overflowed) = {
let a_offset = ImmTy::from_uint(a_offset, usize_layout);
let b_offset = ImmTy::from_uint(b_offset, usize_layout);
self.binary_op(BinOp::SubWithOverflow, &a_offset, &b_offset)?
.to_scalar_pair()
};
if overflowed.to_bool()? {
// a < b
if intrinsic_name == sym::ptr_offset_from_unsigned {
throw_ub_custom!(
fluent::const_eval_offset_from_unsigned_overflow,
a_offset = a_offset,
b_offset = b_offset,
is_addr = is_addr,
);
}
// The signed form of the intrinsic allows this. If we interpret the
// difference as isize, we'll get the proper signed difference. If that
// seems *positive* or equal to isize::MIN, they were more than isize::MAX apart.
let dist = val.to_target_isize(self)?;
if dist >= 0 || i128::from(dist) == self.pointer_size().signed_int_min() {
throw_ub_custom!(
fluent::const_eval_offset_from_underflow,
name = intrinsic_name,
);
}
dist
} else {
// b >= a
let dist = val.to_target_isize(self)?;
// If converting to isize produced a *negative* result, we had an overflow
// because they were more than isize::MAX apart.
if dist < 0 {
throw_ub_custom!(
fluent::const_eval_offset_from_overflow,
name = intrinsic_name,
);
}
dist
}
};
// Check that the memory between them is dereferenceable at all, starting from the
// origin pointer: `dist` is `a - b`, so it is based on `b`.
self.check_ptr_access_signed(b, dist, CheckInAllocMsg::Dereferenceable)
.map_err_kind(|_| {
// This could mean they point to different allocations, or they point to the same allocation
// but not the entire range between the pointers is in-bounds.
if let Ok((a_alloc_id, ..)) = self.ptr_try_get_alloc_id(a, 0)
&& let Ok((b_alloc_id, ..)) = self.ptr_try_get_alloc_id(b, 0)
&& a_alloc_id == b_alloc_id
{
err_ub_custom!(
fluent::const_eval_offset_from_out_of_bounds,
name = intrinsic_name,
)
} else {
err_ub_custom!(
fluent::const_eval_offset_from_different_allocations,
name = intrinsic_name,
)
}
})?;
// Then check that this is also dereferenceable from `a`. This ensures that they are
// derived from the same allocation.
self.check_ptr_access_signed(
a,
dist.checked_neg().unwrap(), // i64::MIN is impossible as no allocation can be that large
CheckInAllocMsg::Dereferenceable,
)
.map_err_kind(|_| {
// Make the error more specific.
err_ub_custom!(
fluent::const_eval_offset_from_different_allocations,
name = intrinsic_name,
)
})?;
// Perform division by size to compute return value.
let ret_layout = if intrinsic_name == sym::ptr_offset_from_unsigned {
assert!(0 <= dist && dist <= self.target_isize_max());
usize_layout
} else {
assert!(self.target_isize_min() <= dist && dist <= self.target_isize_max());
isize_layout
};
let pointee_layout = self.layout_of(instance_args.type_at(0))?;
// If ret_layout is unsigned, we checked that so is the distance, so we are good.
let val = ImmTy::from_int(dist, ret_layout);
let size = ImmTy::from_int(pointee_layout.size.bytes(), ret_layout);
self.exact_div(&val, &size, dest)?;
}
sym::simd_insert => {
let index = u64::from(self.read_scalar(&args[1])?.to_u32()?);
let elem = &args[2];
let (input, input_len) = self.project_to_simd(&args[0])?;
let (dest, dest_len) = self.project_to_simd(dest)?;
assert_eq!(input_len, dest_len, "Return vector length must match input length");
// Bounds are not checked by typeck so we have to do it ourselves.
if index >= input_len {
throw_ub_format!(
"`simd_insert` index {index} is out-of-bounds of vector with length {input_len}"
);
}
for i in 0..dest_len {
let place = self.project_index(&dest, i)?;
let value =
if i == index { elem.clone() } else { self.project_index(&input, i)? };
self.copy_op(&value, &place)?;
}
}
sym::simd_extract => {
let index = u64::from(self.read_scalar(&args[1])?.to_u32()?);
let (input, input_len) = self.project_to_simd(&args[0])?;
// Bounds are not checked by typeck so we have to do it ourselves.
if index >= input_len {
throw_ub_format!(
"`simd_extract` index {index} is out-of-bounds of vector with length {input_len}"
);
}
self.copy_op(&self.project_index(&input, index)?, dest)?;
}
sym::black_box => {
// These just return their argument
self.copy_op(&args[0], dest)?;
}
sym::raw_eq => {
let result = self.raw_eq_intrinsic(&args[0], &args[1])?;
self.write_scalar(result, dest)?;
}
sym::typed_swap_nonoverlapping => {
self.typed_swap_nonoverlapping_intrinsic(&args[0], &args[1])?;
}
sym::vtable_size => {
let ptr = self.read_pointer(&args[0])?;
// `None` because we don't know which trait to expect here; any vtable is okay.
let (size, _align) = self.get_vtable_size_and_align(ptr, None)?;
self.write_scalar(Scalar::from_target_usize(size.bytes(), self), dest)?;
}
sym::vtable_align => {
let ptr = self.read_pointer(&args[0])?;
// `None` because we don't know which trait to expect here; any vtable is okay.
let (_size, align) = self.get_vtable_size_and_align(ptr, None)?;
self.write_scalar(Scalar::from_target_usize(align.bytes(), self), dest)?;
}
sym::minnumf16 => self.float_min_intrinsic::<Half>(args, dest)?,
sym::minnumf32 => self.float_min_intrinsic::<Single>(args, dest)?,
sym::minnumf64 => self.float_min_intrinsic::<Double>(args, dest)?,
sym::minnumf128 => self.float_min_intrinsic::<Quad>(args, dest)?,
sym::minimumf16 => self.float_minimum_intrinsic::<Half>(args, dest)?,
sym::minimumf32 => self.float_minimum_intrinsic::<Single>(args, dest)?,
sym::minimumf64 => self.float_minimum_intrinsic::<Double>(args, dest)?,
sym::minimumf128 => self.float_minimum_intrinsic::<Quad>(args, dest)?,
sym::maxnumf16 => self.float_max_intrinsic::<Half>(args, dest)?,
sym::maxnumf32 => self.float_max_intrinsic::<Single>(args, dest)?,
sym::maxnumf64 => self.float_max_intrinsic::<Double>(args, dest)?,
sym::maxnumf128 => self.float_max_intrinsic::<Quad>(args, dest)?,
sym::maximumf16 => self.float_maximum_intrinsic::<Half>(args, dest)?,
sym::maximumf32 => self.float_maximum_intrinsic::<Single>(args, dest)?,
sym::maximumf64 => self.float_maximum_intrinsic::<Double>(args, dest)?,
sym::maximumf128 => self.float_maximum_intrinsic::<Quad>(args, dest)?,
sym::copysignf16 => self.float_copysign_intrinsic::<Half>(args, dest)?,
sym::copysignf32 => self.float_copysign_intrinsic::<Single>(args, dest)?,
sym::copysignf64 => self.float_copysign_intrinsic::<Double>(args, dest)?,
sym::copysignf128 => self.float_copysign_intrinsic::<Quad>(args, dest)?,
sym::fabsf16 => self.float_abs_intrinsic::<Half>(args, dest)?,
sym::fabsf32 => self.float_abs_intrinsic::<Single>(args, dest)?,
sym::fabsf64 => self.float_abs_intrinsic::<Double>(args, dest)?,
sym::fabsf128 => self.float_abs_intrinsic::<Quad>(args, dest)?,
sym::floorf16 => self.float_round_intrinsic::<Half>(
args,
dest,
rustc_apfloat::Round::TowardNegative,
)?,
sym::floorf32 => self.float_round_intrinsic::<Single>(
args,
dest,
rustc_apfloat::Round::TowardNegative,
)?,
sym::floorf64 => self.float_round_intrinsic::<Double>(
args,
dest,
rustc_apfloat::Round::TowardNegative,
)?,
sym::floorf128 => self.float_round_intrinsic::<Quad>(
args,
dest,
rustc_apfloat::Round::TowardNegative,
)?,
sym::ceilf16 => self.float_round_intrinsic::<Half>(
args,
dest,
rustc_apfloat::Round::TowardPositive,
)?,
sym::ceilf32 => self.float_round_intrinsic::<Single>(
args,
dest,
rustc_apfloat::Round::TowardPositive,
)?,
sym::ceilf64 => self.float_round_intrinsic::<Double>(
args,
dest,
rustc_apfloat::Round::TowardPositive,
)?,
sym::ceilf128 => self.float_round_intrinsic::<Quad>(
args,
dest,
rustc_apfloat::Round::TowardPositive,
)?,
sym::truncf16 => {
self.float_round_intrinsic::<Half>(args, dest, rustc_apfloat::Round::TowardZero)?
}
sym::truncf32 => {
self.float_round_intrinsic::<Single>(args, dest, rustc_apfloat::Round::TowardZero)?
}
sym::truncf64 => {
self.float_round_intrinsic::<Double>(args, dest, rustc_apfloat::Round::TowardZero)?
}
sym::truncf128 => {
self.float_round_intrinsic::<Quad>(args, dest, rustc_apfloat::Round::TowardZero)?
}
sym::roundf16 => self.float_round_intrinsic::<Half>(
args,
dest,
rustc_apfloat::Round::NearestTiesToAway,
)?,
sym::roundf32 => self.float_round_intrinsic::<Single>(
args,
dest,
rustc_apfloat::Round::NearestTiesToAway,
)?,
sym::roundf64 => self.float_round_intrinsic::<Double>(
args,
dest,
rustc_apfloat::Round::NearestTiesToAway,
)?,
sym::roundf128 => self.float_round_intrinsic::<Quad>(
args,
dest,
rustc_apfloat::Round::NearestTiesToAway,
)?,
sym::round_ties_even_f16 => self.float_round_intrinsic::<Half>(
args,
dest,
rustc_apfloat::Round::NearestTiesToEven,
)?,
sym::round_ties_even_f32 => self.float_round_intrinsic::<Single>(
args,
dest,
rustc_apfloat::Round::NearestTiesToEven,
)?,
sym::round_ties_even_f64 => self.float_round_intrinsic::<Double>(
args,
dest,
rustc_apfloat::Round::NearestTiesToEven,
)?,
sym::round_ties_even_f128 => self.float_round_intrinsic::<Quad>(
args,
dest,
rustc_apfloat::Round::NearestTiesToEven,
)?,
// Unsupported intrinsic: skip the return_to_block below.
_ => return interp_ok(false),
}
trace!("{:?}", self.dump_place(&dest.clone().into()));
self.return_to_block(ret)?;
interp_ok(true)
}
pub(super) fn eval_nondiverging_intrinsic(
&mut self,
intrinsic: &NonDivergingIntrinsic<'tcx>,
) -> InterpResult<'tcx> {
match intrinsic {
NonDivergingIntrinsic::Assume(op) => {
let op = self.eval_operand(op, None)?;
let cond = self.read_scalar(&op)?.to_bool()?;
if !cond {
throw_ub_custom!(fluent::const_eval_assume_false);
}
interp_ok(())
}
NonDivergingIntrinsic::CopyNonOverlapping(mir::CopyNonOverlapping {
count,
src,
dst,
}) => {
let src = self.eval_operand(src, None)?;
let dst = self.eval_operand(dst, None)?;
let count = self.eval_operand(count, None)?;
self.copy_intrinsic(&src, &dst, &count, /* nonoverlapping */ true)
}
}
}
pub fn numeric_intrinsic(
&self,
name: Symbol,
val: Scalar<M::Provenance>,
layout: TyAndLayout<'tcx>,
ret_layout: TyAndLayout<'tcx>,
) -> InterpResult<'tcx, Scalar<M::Provenance>> {
assert!(layout.ty.is_integral(), "invalid type for numeric intrinsic: {}", layout.ty);
let bits = val.to_bits(layout.size)?; // these operations all ignore the sign
let extra = 128 - u128::from(layout.size.bits());
let bits_out = match name {
sym::ctpop => u128::from(bits.count_ones()),
sym::ctlz_nonzero | sym::cttz_nonzero if bits == 0 => {
throw_ub_custom!(fluent::const_eval_call_nonzero_intrinsic, name = name,);
}
sym::ctlz | sym::ctlz_nonzero => u128::from(bits.leading_zeros()) - extra,
sym::cttz | sym::cttz_nonzero => u128::from((bits << extra).trailing_zeros()) - extra,
sym::bswap => {
assert_eq!(layout, ret_layout);
(bits << extra).swap_bytes()
}
sym::bitreverse => {
assert_eq!(layout, ret_layout);
(bits << extra).reverse_bits()
}
_ => bug!("not a numeric intrinsic: {}", name),
};
interp_ok(Scalar::from_uint(bits_out, ret_layout.size))
}
pub fn exact_div(
&mut self,
a: &ImmTy<'tcx, M::Provenance>,
b: &ImmTy<'tcx, M::Provenance>,
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx> {
assert_eq!(a.layout.ty, b.layout.ty);
assert_matches!(a.layout.ty.kind(), ty::Int(..) | ty::Uint(..));
// Performs an exact division, resulting in undefined behavior where
// `x % y != 0` or `y == 0` or `x == T::MIN && y == -1`.
// First, check x % y != 0 (or if that computation overflows).
let rem = self.binary_op(BinOp::Rem, a, b)?;
// sign does not matter for 0 test, so `to_bits` is fine
if rem.to_scalar().to_bits(a.layout.size)? != 0 {
throw_ub_custom!(
fluent::const_eval_exact_div_has_remainder,
a = format!("{a}"),
b = format!("{b}")
)
}
// `Rem` says this is all right, so we can let `Div` do its job.
let res = self.binary_op(BinOp::Div, a, b)?;
self.write_immediate(*res, dest)
}
pub fn saturating_arith(
&self,
mir_op: BinOp,
l: &ImmTy<'tcx, M::Provenance>,
r: &ImmTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, Scalar<M::Provenance>> {
assert_eq!(l.layout.ty, r.layout.ty);
assert_matches!(l.layout.ty.kind(), ty::Int(..) | ty::Uint(..));
assert_matches!(mir_op, BinOp::Add | BinOp::Sub);
let (val, overflowed) =
self.binary_op(mir_op.wrapping_to_overflowing().unwrap(), l, r)?.to_scalar_pair();
interp_ok(if overflowed.to_bool()? {
let size = l.layout.size;
if l.layout.backend_repr.is_signed() {
// For signed ints the saturated value depends on the sign of the first
// term since the sign of the second term can be inferred from this and
// the fact that the operation has overflowed (if either is 0 no
// overflow can occur)
let first_term: i128 = l.to_scalar().to_int(l.layout.size)?;
if first_term >= 0 {
// Negative overflow not possible since the positive first term
// can only increase an (in range) negative term for addition
// or corresponding negated positive term for subtraction.
Scalar::from_int(size.signed_int_max(), size)
} else {
// Positive overflow not possible for similar reason.
Scalar::from_int(size.signed_int_min(), size)
}
} else {
// unsigned
if matches!(mir_op, BinOp::Add) {
// max unsigned
Scalar::from_uint(size.unsigned_int_max(), size)
} else {
// underflow to 0
Scalar::from_uint(0u128, size)
}
}
} else {
val
})
}
/// Offsets a pointer by some multiple of its type, returning an error if the pointer leaves its
/// allocation.
pub fn ptr_offset_inbounds(
&self,
ptr: Pointer<Option<M::Provenance>>,
offset_bytes: i64,
) -> InterpResult<'tcx, Pointer<Option<M::Provenance>>> {
// The offset must be in bounds starting from `ptr`.
self.check_ptr_access_signed(
ptr,
offset_bytes,
CheckInAllocMsg::InboundsPointerArithmetic,
)?;
// This also implies that there is no overflow, so we are done.
interp_ok(ptr.wrapping_signed_offset(offset_bytes, self))
}
/// Copy `count*size_of::<T>()` many bytes from `*src` to `*dst`.
pub(crate) fn copy_intrinsic(
&mut self,
src: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
dst: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
count: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
nonoverlapping: bool,
) -> InterpResult<'tcx> {
let count = self.read_target_usize(count)?;
let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap())?;
let (size, align) = (layout.size, layout.align.abi);
let size = self.compute_size_in_bytes(size, count).ok_or_else(|| {
err_ub_custom!(
fluent::const_eval_size_overflow,
name = if nonoverlapping { "copy_nonoverlapping" } else { "copy" }
)
})?;
let src = self.read_pointer(src)?;
let dst = self.read_pointer(dst)?;
self.check_ptr_align(src, align)?;
self.check_ptr_align(dst, align)?;
self.mem_copy(src, dst, size, nonoverlapping)
}
/// Does a *typed* swap of `*left` and `*right`.
fn typed_swap_nonoverlapping_intrinsic(
&mut self,
left: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
right: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
) -> InterpResult<'tcx> {
let left = self.deref_pointer(left)?;
let right = self.deref_pointer(right)?;
assert_eq!(left.layout, right.layout);
assert!(left.layout.is_sized());
let kind = MemoryKind::Stack;
let temp = self.allocate(left.layout, kind)?;
self.copy_op(&left, &temp)?; // checks alignment of `left`
// We want to always enforce non-overlapping, even if this is a scalar type.
// Therefore we directly use the underlying `mem_copy` here.
self.mem_copy(right.ptr(), left.ptr(), left.layout.size, /*nonoverlapping*/ true)?;
// This means we also need to do the validation of the value that used to be in `right`
// ourselves. This value is now in `left.` The one that started out in `left` already got
// validated by the copy above.
if M::enforce_validity(self, left.layout) {
self.validate_operand(
&left.clone().into(),
M::enforce_validity_recursively(self, left.layout),
/*reset_provenance_and_padding*/ true,
)?;
}
self.copy_op(&temp, &right)?; // checks alignment of `right`
self.deallocate_ptr(temp.ptr(), None, kind)?;
interp_ok(())
}
pub fn write_bytes_intrinsic(
&mut self,
dst: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
byte: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
count: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
name: &'static str,
) -> InterpResult<'tcx> {
let layout = self.layout_of(dst.layout.ty.builtin_deref(true).unwrap())?;
let dst = self.read_pointer(dst)?;
let byte = self.read_scalar(byte)?.to_u8()?;
let count = self.read_target_usize(count)?;
// `checked_mul` enforces a too small bound (the correct one would probably be target_isize_max),
// but no actual allocation can be big enough for the difference to be noticeable.
let len = self
.compute_size_in_bytes(layout.size, count)
.ok_or_else(|| err_ub_custom!(fluent::const_eval_size_overflow, name = name))?;
let bytes = std::iter::repeat(byte).take(len.bytes_usize());
self.write_bytes_ptr(dst, bytes)
}
pub(crate) fn compare_bytes_intrinsic(
&mut self,
left: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
right: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
byte_count: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
) -> InterpResult<'tcx, Scalar<M::Provenance>> {
let left = self.read_pointer(left)?;
let right = self.read_pointer(right)?;
let n = Size::from_bytes(self.read_target_usize(byte_count)?);
let left_bytes = self.read_bytes_ptr_strip_provenance(left, n)?;
let right_bytes = self.read_bytes_ptr_strip_provenance(right, n)?;
// `Ordering`'s discriminants are -1/0/+1, so casting does the right thing.
let result = Ord::cmp(left_bytes, right_bytes) as i32;
interp_ok(Scalar::from_i32(result))
}
pub(crate) fn raw_eq_intrinsic(
&mut self,
lhs: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
rhs: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>,
) -> InterpResult<'tcx, Scalar<M::Provenance>> {
let layout = self.layout_of(lhs.layout.ty.builtin_deref(true).unwrap())?;
assert!(layout.is_sized());
let get_bytes = |this: &InterpCx<'tcx, M>,
op: &OpTy<'tcx, <M as Machine<'tcx>>::Provenance>|
-> InterpResult<'tcx, &[u8]> {
let ptr = this.read_pointer(op)?;
this.check_ptr_align(ptr, layout.align.abi)?;
let Some(alloc_ref) = self.get_ptr_alloc(ptr, layout.size)? else {
// zero-sized access
return interp_ok(&[]);
};
alloc_ref.get_bytes_strip_provenance()
};
let lhs_bytes = get_bytes(self, lhs)?;
let rhs_bytes = get_bytes(self, rhs)?;
interp_ok(Scalar::from_bool(lhs_bytes == rhs_bytes))
}
fn float_min_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let a: F = self.read_scalar(&args[0])?.to_float()?;
let b: F = self.read_scalar(&args[1])?.to_float()?;
let res = if a == b {
// They are definitely not NaN (those are never equal), but they could be `+0` and `-0`.
// Let the machine decide which one to return.
M::equal_float_min_max(self, a, b)
} else {
self.adjust_nan(a.min(b), &[a, b])
};
self.write_scalar(res, dest)?;
interp_ok(())
}
fn float_max_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let a: F = self.read_scalar(&args[0])?.to_float()?;
let b: F = self.read_scalar(&args[1])?.to_float()?;
let res = if a == b {
// They are definitely not NaN (those are never equal), but they could be `+0` and `-0`.
// Let the machine decide which one to return.
M::equal_float_min_max(self, a, b)
} else {
self.adjust_nan(a.max(b), &[a, b])
};
self.write_scalar(res, dest)?;
interp_ok(())
}
fn float_minimum_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let a: F = self.read_scalar(&args[0])?.to_float()?;
let b: F = self.read_scalar(&args[1])?.to_float()?;
let res = a.minimum(b);
let res = self.adjust_nan(res, &[a, b]);
self.write_scalar(res, dest)?;
interp_ok(())
}
fn float_maximum_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let a: F = self.read_scalar(&args[0])?.to_float()?;
let b: F = self.read_scalar(&args[1])?.to_float()?;
let res = a.maximum(b);
let res = self.adjust_nan(res, &[a, b]);
self.write_scalar(res, dest)?;
interp_ok(())
}
fn float_copysign_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let a: F = self.read_scalar(&args[0])?.to_float()?;
let b: F = self.read_scalar(&args[1])?.to_float()?;
// bitwise, no NaN adjustments
self.write_scalar(a.copy_sign(b), dest)?;
interp_ok(())
}
fn float_abs_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let x: F = self.read_scalar(&args[0])?.to_float()?;
// bitwise, no NaN adjustments
self.write_scalar(x.abs(), dest)?;
interp_ok(())
}
fn float_round_intrinsic<F>(
&mut self,
args: &[OpTy<'tcx, M::Provenance>],
dest: &PlaceTy<'tcx, M::Provenance>,
mode: rustc_apfloat::Round,
) -> InterpResult<'tcx, ()>
where
F: rustc_apfloat::Float + rustc_apfloat::FloatConvert<F> + Into<Scalar<M::Provenance>>,
{
let x: F = self.read_scalar(&args[0])?.to_float()?;
let res = x.round_to_integral(mode).value;
let res = self.adjust_nan(res, &[x]);
self.write_scalar(res, dest)?;
interp_ok(())
}
}