13 impl<'mir, 'tcx> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
14 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
15 fn find_mir_or_eval_fn(
17 instance: ty::Instance<'tcx>,
18 args: &[OpTy<'tcx, Tag>],
19 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
20 unwind: Option<mir::BasicBlock>
21 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
22 let this = self.eval_context_mut();
24 "eval_fn_call: {:#?}, {:?}",
29 // There are some more lang items we want to hook that CTFE does not hook (yet).
30 if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
31 let (dest, ret) = ret.unwrap();
33 .align_offset(args[0], args[1])?
34 .unwrap_or_else(|| this.truncate(u128::max_value(), dest.layout));
35 this.write_scalar(Scalar::from_uint(n, dest.layout.size), dest)?;
36 this.go_to_block(ret);
40 // Try to see if we can do something about foreign items.
41 if this.tcx.is_foreign_item(instance.def_id()) {
42 // An external function call that does not have a MIR body. We either find MIR elsewhere
43 // or emulate its effect.
44 // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
45 // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
47 // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
48 return this.emulate_foreign_item(instance.def_id(), args, ret, unwind);
51 // Otherwise, load the MIR.
52 Ok(Some(&*this.load_mir(instance.def, None)?))
57 ptr_op: OpTy<'tcx, Tag>,
58 align_op: OpTy<'tcx, Tag>,
59 ) -> InterpResult<'tcx, Option<u128>> {
60 let this = self.eval_context_mut();
62 let req_align = this.force_bits(
63 this.read_scalar(align_op)?.not_undef()?,
67 // FIXME: This should actually panic in the interpreted program
68 if !req_align.is_power_of_two() {
69 throw_unsup_format!("Required alignment should always be a power of two")
72 let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
74 if let Ok(ptr) = this.force_ptr(ptr_scalar) {
75 let cur_align = this.memory.get_size_and_align(ptr.alloc_id, AllocCheck::MaybeDead)?.1.bytes() as usize;
76 if cur_align >= req_align {
77 // if the allocation alignment is at least the required alignment we use the
78 // libcore implementation
80 (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8)
81 .align_offset(req_align) as u128,
85 // If the allocation alignment is smaller than then required alignment or the pointer was
86 // actually an integer, we return `None`