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interpret: make numeric_intrinsic accessible from Miri #118565

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Dec 5, 2023
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interpret: make numeric_intrinsic accessible from Miri #118565

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82 changes: 36 additions & 46 deletions compiler/rustc_const_eval/src/interpret/intrinsics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,17 +3,22 @@
//! and miri.

use rustc_hir::def_id::DefId;
use rustc_middle::mir::{
self,
interpret::{Allocation, ConstAllocation, GlobalId, InterpResult, PointerArithmetic, Scalar},
BinOp, ConstValue, NonDivergingIntrinsic,
};
use rustc_middle::ty;
use rustc_middle::ty::layout::{LayoutOf as _, ValidityRequirement};
use rustc_middle::ty::GenericArgsRef;
use rustc_middle::ty::{Ty, TyCtxt};
use rustc_middle::{
mir::{
self,
interpret::{
Allocation, ConstAllocation, GlobalId, InterpResult, PointerArithmetic, Scalar,
},
BinOp, ConstValue, NonDivergingIntrinsic,
},
ty::layout::TyAndLayout,
};
use rustc_span::symbol::{sym, Symbol};
use rustc_target::abi::{Abi, Primitive, Size};
use rustc_target::abi::Size;

use super::{
util::ensure_monomorphic_enough, CheckInAllocMsg, ImmTy, InterpCx, Machine, OpTy, PlaceTy,
Expand All @@ -22,23 +27,6 @@ use super::{

use crate::fluent_generated as fluent;

fn numeric_intrinsic<Prov>(name: Symbol, bits: u128, kind: Primitive) -> Scalar<Prov> {
let size = match kind {
Primitive::Int(integer, _) => integer.size(),
_ => bug!("invalid `{}` argument: {:?}", name, bits),
};
let extra = 128 - u128::from(size.bits());
let bits_out = match name {
sym::ctpop => u128::from(bits.count_ones()),
sym::ctlz => u128::from(bits.leading_zeros()) - extra,
sym::cttz => u128::from((bits << extra).trailing_zeros()) - extra,
sym::bswap => (bits << extra).swap_bytes(),
sym::bitreverse => (bits << extra).reverse_bits(),
_ => bug!("not a numeric intrinsic: {}", name),
};
Scalar::from_uint(bits_out, size)
}

/// 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>) -> ConstAllocation<'tcx> {
let path = crate::util::type_name(tcx, ty);
Expand Down Expand Up @@ -179,30 +167,9 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
| sym::bswap
| sym::bitreverse => {
let ty = instance_args.type_at(0);
let layout_of = self.layout_of(ty)?;
let layout = self.layout_of(ty)?;
let val = self.read_scalar(&args[0])?;
let bits = val.to_bits(layout_of.size)?;
let kind = match layout_of.abi {
Abi::Scalar(scalar) => scalar.primitive(),
_ => span_bug!(
self.cur_span(),
"{} called on invalid type {:?}",
intrinsic_name,
ty
),
};
let (nonzero, actual_intrinsic_name) = match intrinsic_name {
sym::cttz_nonzero => (true, sym::cttz),
sym::ctlz_nonzero => (true, sym::ctlz),
other => (false, other),
};
if nonzero && bits == 0 {
throw_ub_custom!(
fluent::const_eval_call_nonzero_intrinsic,
name = intrinsic_name,
);
}
let out_val = numeric_intrinsic(actual_intrinsic_name, bits, kind);
let out_val = self.numeric_intrinsic(intrinsic_name, val, layout)?;
self.write_scalar(out_val, dest)?;
}
sym::saturating_add | sym::saturating_sub => {
Expand Down Expand Up @@ -493,6 +460,29 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
}

pub fn numeric_intrinsic(
&self,
name: Symbol,
val: Scalar<M::Provenance>,
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)?;
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 => (bits << extra).swap_bytes(),
sym::bitreverse => (bits << extra).reverse_bits(),
_ => bug!("not a numeric intrinsic: {}", name),
};
Ok(Scalar::from_uint(bits_out, layout.size))
}

pub fn exact_div(
&mut self,
a: &ImmTy<'tcx, M::Provenance>,
Expand Down