14 // End module management, begin local code
18 use rustc_middle::{mir, ty};
19 use rustc_target::spec::abi::Abi;
22 use helpers::check_arg_count;
24 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
25 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
26 fn find_mir_or_eval_fn(
28 instance: ty::Instance<'tcx>,
30 args: &[OpTy<'tcx, Tag>],
31 ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
32 unwind: StackPopUnwind,
33 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
34 let this = self.eval_context_mut();
35 trace!("eval_fn_call: {:#?}, {:?}", instance, ret.map(|p| p.0));
37 // There are some more lang items we want to hook that CTFE does not hook (yet).
38 if this.tcx.lang_items().align_offset_fn() == Some(instance.def.def_id()) {
39 let &[ref ptr, ref align] = check_arg_count(args)?;
40 if this.align_offset(ptr, align, ret, unwind)? {
45 // Try to see if we can do something about foreign items.
46 if this.tcx.is_foreign_item(instance.def_id()) {
47 // An external function call that does not have a MIR body. We either find MIR elsewhere
48 // or emulate its effect.
49 // This will be Ok(None) if we're emulating the intrinsic entirely within Miri (no need
50 // to run extra MIR), and Ok(Some(body)) if we found MIR to run for the
52 // Any needed call to `goto_block` will be performed by `emulate_foreign_item`.
53 return this.emulate_foreign_item(instance.def_id(), abi, args, ret, unwind);
56 // Otherwise, load the MIR.
57 Ok(Some(&*this.load_mir(instance.def, None)?))
60 /// Returns `true` if the computation was performed, and `false` if we should just evaluate
61 /// the actual MIR of `align_offset`.
64 ptr_op: &OpTy<'tcx, Tag>,
65 align_op: &OpTy<'tcx, Tag>,
66 ret: Option<(&PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
67 unwind: StackPopUnwind,
68 ) -> InterpResult<'tcx, bool> {
69 let this = self.eval_context_mut();
70 let (dest, ret) = ret.unwrap();
72 if this.memory.extra.check_alignment != AlignmentCheck::Symbolic {
73 // Just use actual implementation.
77 let req_align = this.read_scalar(align_op)?.to_machine_usize(this)?;
79 // Stop if the alignment is not a power of two.
80 if !req_align.is_power_of_two() {
81 this.start_panic("align_offset: align is not a power-of-two", unwind)?;
82 return Ok(true); // nothing left to do
85 let ptr = this.read_pointer(ptr_op)?;
86 if let Ok(ptr) = ptr.into_pointer_or_addr() {
87 // Only do anything if we can identify the allocation this goes to.
89 this.memory.get_size_and_align(ptr.provenance.alloc_id, AllocCheck::MaybeDead)?;
90 if cur_align.bytes() >= req_align {
91 // If the allocation alignment is at least the required alignment we use the
92 // real implementation.
97 // Return error result (usize::MAX), and jump to caller.
98 this.write_scalar(Scalar::from_machine_usize(this.machine_usize_max(), this), dest)?;
99 this.go_to_block(ret);