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();
23 trace!("eval_fn_call: {:#?}, {:?}", instance, ret.map(|p| *p.0));
25 // There are some more lang items we want to hook that CTFE does not hook (yet).
26 if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
27 this.align_offset(args[0], args[1], ret, unwind)?;
31 // Try to see if we can do something about foreign items.
32 if this.tcx.is_foreign_item(instance.def_id()) {
33 // An external function call that does not have a MIR body. We either find MIR elsewhere
34 // or emulate its effect.
35 // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
36 // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
38 // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
39 return this.emulate_foreign_item(instance.def_id(), args, ret, unwind);
42 // Otherwise, load the MIR.
43 Ok(Some(&*this.load_mir(instance.def, None)?))
48 ptr_op: OpTy<'tcx, Tag>,
49 align_op: OpTy<'tcx, Tag>,
50 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
51 unwind: Option<mir::BasicBlock>,
52 ) -> InterpResult<'tcx> {
53 let this = self.eval_context_mut();
54 let (dest, ret) = ret.unwrap();
57 .force_bits(this.read_scalar(align_op)?.not_undef()?, this.pointer_size())?
60 // Stop if the alignment is not a power of two.
61 if !req_align.is_power_of_two() {
62 return this.start_panic("align_offset: align is not a power-of-two", unwind);
65 let ptr_scalar = this.read_scalar(ptr_op)?.not_undef()?;
67 // Default: no result.
68 let mut result = this.truncate(u128::MAX, dest.layout);
69 if let Ok(ptr) = this.force_ptr(ptr_scalar) {
70 // Only do anything if we can identify the allocation this goes to.
72 this.memory.get_size_and_align(ptr.alloc_id, AllocCheck::MaybeDead)?.1.bytes()
74 if cur_align >= req_align {
75 // If the allocation alignment is at least the required alignment we use the
76 // libcore implementation
77 result = (this.force_bits(ptr_scalar, this.pointer_size())? as *const i8).align_offset(req_align) as u128;
81 // Return result, and jump to caller.
82 this.write_scalar(Scalar::from_uint(result, dest.layout.size), dest)?;
83 this.go_to_block(ret);