message: Add align_offset for integers
diff: @@ -27,25 +27,7 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  }
  // There are some more lang items we want to hook that CTFE does not hook (yet).
  if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
  -
  - let n = {
  - let ptr = this.force_ptr(this.read_scalar(args[0])?.not_undef()?)?;
  - let align = this.force_bits(
  - this.read_scalar(args[1])?.not_undef()?,
  - this.pointer_size()
  - )? as usize;
  -
  - let stride = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
  - // if the allocation alignment is at least the required alignment, we use the
  - // libcore implementation
  - if stride >= align {
  - ((stride + ptr.offset.bytes() as usize) as *const ())
  - .align_offset(align) as u128
  - } else {
  - u128::max_value()
  - }
  - };
  -
  + let n = this.align_offset(args[0], args[1])?;
  let dest = dest.unwrap();
  let n = this.truncate(n, dest.layout);
  this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
  @@ -65,4 +47,33 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
  // Otherwise, load the MIR.
  Ok(Some(this.load_mir(instance.def, None)?))
  }
  +
  + fn align_offset(
  + &mut self,
  + ptr_op: OpTy<'tcx, Tag>,
  + align_op: OpTy<'tcx, Tag>
  + ) -> InterpResult<'tcx, u128> {
  + let this = self.eval_context_mut();
  +
  + let req_align = this.force_bits(
  + this.read_scalar(align_op)?.not_undef()?,
  + this.pointer_size()
  + )? as usize;
  +
  + let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
  +
  + if let Scalar::Ptr(ptr) = ptr_scalar {
  + let cur_align = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
  + if cur_align < req_align {
  + return Ok(u128::max_value());
  + }
  + }
  +
  + // if the allocation alignment is at least the required alignment or if the pointer is an
  + // integer, we use the libcore implementation
  + Ok(
  + (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
  + .align_offset(req_align) as u128
  + )
  + }
  }
  