85 lines
3.2 KiB
Rust
85 lines
3.2 KiB
Rust
use log::trace;
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use rustc_middle::{mir, ty::Ty};
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use crate::*;
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pub trait EvalContextExt<'tcx> {
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fn binary_ptr_op(
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&self,
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bin_op: mir::BinOp,
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left: ImmTy<'tcx, Tag>,
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right: ImmTy<'tcx, Tag>,
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) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)>;
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fn ptr_eq(&self, left: Scalar<Tag>, right: Scalar<Tag>) -> InterpResult<'tcx, bool>;
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}
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impl<'mir, 'tcx> EvalContextExt<'tcx> for super::MiriEvalContext<'mir, 'tcx> {
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fn binary_ptr_op(
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&self,
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bin_op: mir::BinOp,
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left: ImmTy<'tcx, Tag>,
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right: ImmTy<'tcx, Tag>,
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) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
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use rustc_middle::mir::BinOp::*;
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trace!("ptr_op: {:?} {:?} {:?}", *left, bin_op, *right);
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Ok(match bin_op {
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Eq | Ne => {
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// This supports fat pointers.
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#[rustfmt::skip]
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let eq = match (*left, *right) {
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(Immediate::Scalar(left), Immediate::Scalar(right)) => {
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self.ptr_eq(left.check_init()?, right.check_init()?)?
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}
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(Immediate::ScalarPair(left1, left2), Immediate::ScalarPair(right1, right2)) => {
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self.ptr_eq(left1.check_init()?, right1.check_init()?)?
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&& self.ptr_eq(left2.check_init()?, right2.check_init()?)?
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}
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_ => bug!("Type system should not allow comparing Scalar with ScalarPair"),
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};
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(Scalar::from_bool(if bin_op == Eq { eq } else { !eq }), false, self.tcx.types.bool)
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}
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Lt | Le | Gt | Ge => {
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// Just compare the integers.
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// TODO: Do we really want to *always* do that, even when comparing two live in-bounds pointers?
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let left = self.force_bits(left.to_scalar()?, left.layout.size)?;
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let right = self.force_bits(right.to_scalar()?, right.layout.size)?;
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let res = match bin_op {
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Lt => left < right,
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Le => left <= right,
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Gt => left > right,
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Ge => left >= right,
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_ => bug!("We already established it has to be one of these operators."),
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};
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(Scalar::from_bool(res), false, self.tcx.types.bool)
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}
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Offset => {
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let pointee_ty =
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left.layout.ty.builtin_deref(true).expect("Offset called on non-ptr type").ty;
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let ptr = self.ptr_offset_inbounds(
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left.to_scalar()?,
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pointee_ty,
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right.to_scalar()?.to_machine_isize(self)?,
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)?;
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(ptr, false, left.layout.ty)
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}
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_ => bug!("Invalid operator on pointers: {:?}", bin_op),
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})
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}
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fn ptr_eq(&self, left: Scalar<Tag>, right: Scalar<Tag>) -> InterpResult<'tcx, bool> {
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let size = self.pointer_size();
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// Just compare the integers.
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// TODO: Do we really want to *always* do that, even when comparing two live in-bounds pointers?
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let left = self.force_bits(left, size)?;
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let right = self.force_bits(right, size)?;
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Ok(left == right)
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}
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}
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