11 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
12 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
15 instance: ty::Instance<'tcx>,
16 args: &[OpTy<'tcx, Tag>],
17 dest: Option<PlaceTy<'tcx, Tag>>,
18 ret: Option<mir::BasicBlock>,
19 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
20 let this = self.eval_context_mut();
21 trace!("eval_fn_call: {:#?}, {:?}", instance, dest.map(|place| *place));
23 // First, run the common hooks also supported by CTFE.
24 if this.hook_fn(instance, args, dest)? {
25 this.goto_block(ret)?;
28 // There are some more lang items we want to hook that CTFE does not hook (yet).
29 if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
30 let dest = dest.unwrap();
31 let n = this.align_offset(args[0], args[1], dest.layout)?;
32 this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
33 this.goto_block(ret)?;
37 // Try to see if we can do something about foreign items.
38 if this.tcx.is_foreign_item(instance.def_id()) {
39 // An external function that we cannot find MIR for, but we can still run enough
40 // of them to make miri viable.
41 this.emulate_foreign_item(instance.def_id(), args, dest, ret)?;
42 // `goto_block` already handled.
46 // Otherwise, load the MIR.
47 Ok(Some(this.load_mir(instance.def, None)?))
52 ptr_op: OpTy<'tcx, Tag>,
53 align_op: OpTy<'tcx, Tag>,
54 layout: ty::layout::TyLayout<'tcx>,
55 ) -> InterpResult<'tcx, u128> {
56 let this = self.eval_context_mut();
58 let req_align = this.force_bits(
59 this.read_scalar(align_op)?.not_undef()?,
63 // FIXME: This should actually panic in the interpreted program
64 if !req_align.is_power_of_two() {
65 throw_unsup_format!("Required alignment should always be a power of two")
68 let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
70 if let Scalar::Ptr(ptr) = ptr_scalar {
71 let cur_align = this.memory().get(ptr.alloc_id)?.align.bytes() as usize;
72 if cur_align < req_align {
73 return Ok(this.truncate(u128::max_value(), layout));
77 // if the allocation alignment is at least the required alignment or if the pointer is an
78 // integer, we use the libcore implementation
80 (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
81 .align_offset(req_align) as u128