3 use rustc_middle::ty::layout::{FnAbiOf, LayoutOf};
4 use rustc_middle::ty::Instance;
10 use rustc_target::abi::call::{ArgAbi, ArgAttribute, ArgAttributes, FnAbi, PassMode};
11 use rustc_target::spec::abi::Abi;
14 FnVal, ImmTy, Immediate, InterpCx, InterpResult, MPlaceTy, Machine, MemoryKind, OpTy, Operand,
15 PlaceTy, Scalar, StackPopCleanup, StackPopUnwind,
18 impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
19 pub(super) fn eval_terminator(
21 terminator: &mir::Terminator<'tcx>,
22 ) -> InterpResult<'tcx> {
23 use rustc_middle::mir::TerminatorKind::*;
24 match terminator.kind {
26 self.pop_stack_frame(/* unwinding */ false)?
29 Goto { target } => self.go_to_block(target),
31 SwitchInt { ref discr, ref targets, switch_ty } => {
32 let discr = self.read_immediate(&self.eval_operand(discr, None)?)?;
33 trace!("SwitchInt({:?})", *discr);
34 assert_eq!(discr.layout.ty, switch_ty);
36 // Branch to the `otherwise` case by default, if no match is found.
37 assert!(!targets.iter().is_empty());
38 let mut target_block = targets.otherwise();
40 for (const_int, target) in targets.iter() {
41 // Compare using MIR BinOp::Eq, to also support pointer values.
42 // (Avoiding `self.binary_op` as that does some redundant layout computation.)
44 .overflowing_binary_op(
47 &ImmTy::from_uint(const_int, discr.layout),
51 target_block = target;
56 self.go_to_block(target_block);
68 let old_stack = self.frame_idx();
69 let old_loc = self.frame().loc;
70 let func = self.eval_operand(func, None)?;
71 let args = self.eval_operands(args)?;
73 let fn_sig_binder = func.layout.ty.fn_sig(*self.tcx);
75 self.tcx.normalize_erasing_late_bound_regions(self.param_env, fn_sig_binder);
76 let extra_args = &args[fn_sig.inputs().len()..];
77 let extra_args = self.tcx.mk_type_list(extra_args.iter().map(|arg| arg.layout.ty));
79 let (fn_val, fn_abi, with_caller_location) = match *func.layout.ty.kind() {
81 let fn_ptr = self.read_pointer(&func)?;
82 let fn_val = self.get_ptr_fn(fn_ptr)?;
83 (fn_val, self.fn_abi_of_fn_ptr(fn_sig_binder, extra_args)?, false)
85 ty::FnDef(def_id, substs) => {
87 self.resolve(ty::WithOptConstParam::unknown(def_id), substs)?;
89 FnVal::Instance(instance),
90 self.fn_abi_of_instance(instance, extra_args)?,
91 instance.def.requires_caller_location(*self.tcx),
95 terminator.source_info.span,
96 "invalid callee of type {:?}",
101 let destination = self.eval_place(destination)?;
104 (fn_sig.abi, fn_abi),
106 with_caller_location,
109 match (cleanup, fn_abi.can_unwind) {
110 (Some(cleanup), true) => StackPopUnwind::Cleanup(*cleanup),
111 (None, true) => StackPopUnwind::Skip,
112 (_, false) => StackPopUnwind::NotAllowed,
115 // Sanity-check that `eval_fn_call` either pushed a new frame or
116 // did a jump to another block.
117 if self.frame_idx() == old_stack && self.frame().loc == old_loc {
118 span_bug!(terminator.source_info.span, "evaluating this call made no progress");
122 Drop { place, target, unwind } => {
123 let place = self.eval_place(place)?;
124 let ty = place.layout.ty;
125 trace!("TerminatorKind::drop: {:?}, type {}", place, ty);
127 let instance = Instance::resolve_drop_in_place(*self.tcx, ty);
128 self.drop_in_place(&place, instance, target, unwind)?;
131 Assert { ref cond, expected, ref msg, target, cleanup } => {
133 self.read_immediate(&self.eval_operand(cond, None)?)?.to_scalar()?.to_bool()?;
134 if expected == cond_val {
135 self.go_to_block(target);
137 M::assert_panic(self, msg, cleanup)?;
142 M::abort(self, "the program aborted execution".to_owned())?;
145 // When we encounter Resume, we've finished unwinding
146 // cleanup for the current stack frame. We pop it in order
147 // to continue unwinding the next frame
149 trace!("unwinding: resuming from cleanup");
150 // By definition, a Resume terminator means
151 // that we're unwinding
152 self.pop_stack_frame(/* unwinding */ true)?;
156 // It is UB to ever encounter this.
157 Unreachable => throw_ub!(Unreachable),
159 // These should never occur for MIR we actually run.
160 DropAndReplace { .. }
164 | GeneratorDrop => span_bug!(
165 terminator.source_info.span,
166 "{:#?} should have been eliminated by MIR pass",
170 // Inline assembly can't be interpreted.
171 InlineAsm { .. } => throw_unsup_format!("inline assembly is not supported"),
177 fn check_argument_compat(
178 caller_abi: &ArgAbi<'tcx, Ty<'tcx>>,
179 callee_abi: &ArgAbi<'tcx, Ty<'tcx>>,
181 // Heuristic for type comparison.
182 let layout_compat = || {
183 if caller_abi.layout.ty == callee_abi.layout.ty {
187 if caller_abi.layout.is_unsized() || callee_abi.layout.is_unsized() {
188 // No, no, no. We require the types to *exactly* match for unsized arguments. If
189 // these are somehow unsized "in a different way" (say, `dyn Trait` vs `[i32]`),
190 // then who knows what happens.
193 if caller_abi.layout.size != callee_abi.layout.size
194 || caller_abi.layout.align.abi != callee_abi.layout.align.abi
196 // This cannot go well...
199 // The rest *should* be okay, but we are extra conservative.
200 match (caller_abi.layout.abi, callee_abi.layout.abi) {
201 // Different valid ranges are okay (once we enforce validity,
202 // that will take care to make it UB to leave the range, just
203 // like for transmute).
204 (abi::Abi::Scalar(caller), abi::Abi::Scalar(callee)) => {
205 caller.primitive() == callee.primitive()
208 abi::Abi::ScalarPair(caller1, caller2),
209 abi::Abi::ScalarPair(callee1, callee2),
211 caller1.primitive() == callee1.primitive()
212 && caller2.primitive() == callee2.primitive()
218 // Padding must be fully equal.
219 let pad_compat = || caller_abi.pad == callee_abi.pad;
220 // When comparing the PassMode, we have to be smart about comparing the attributes.
221 let arg_attr_compat = |a1: ArgAttributes, a2: ArgAttributes| {
222 // There's only one regular attribute that matters for the call ABI: InReg.
223 // Everything else is things like noalias, dereferencable, nonnull, ...
224 // (This also applies to pointee_size, pointee_align.)
225 if a1.regular.contains(ArgAttribute::InReg) != a2.regular.contains(ArgAttribute::InReg)
229 // We also compare the sign extension mode -- this could let the callee make assumptions
230 // about bits that conceptually were not even passed.
231 if a1.arg_ext != a2.arg_ext {
236 let mode_compat = || match (caller_abi.mode, callee_abi.mode) {
237 (PassMode::Ignore, PassMode::Ignore) => true,
238 (PassMode::Direct(a1), PassMode::Direct(a2)) => arg_attr_compat(a1, a2),
239 (PassMode::Pair(a1, b1), PassMode::Pair(a2, b2)) => {
240 arg_attr_compat(a1, a2) && arg_attr_compat(b1, b2)
242 (PassMode::Cast(c1), PassMode::Cast(c2)) => c1 == c2,
244 PassMode::Indirect { attrs: a1, extra_attrs: None, on_stack: s1 },
245 PassMode::Indirect { attrs: a2, extra_attrs: None, on_stack: s2 },
246 ) => arg_attr_compat(a1, a2) && s1 == s2,
248 PassMode::Indirect { attrs: a1, extra_attrs: Some(e1), on_stack: s1 },
249 PassMode::Indirect { attrs: a2, extra_attrs: Some(e2), on_stack: s2 },
250 ) => arg_attr_compat(a1, a2) && arg_attr_compat(e1, e2) && s1 == s2,
254 if layout_compat() && pad_compat() && mode_compat() {
258 "check_argument_compat: incompatible ABIs:\ncaller: {:?}\ncallee: {:?}",
265 /// Initialize a single callee argument, checking the types for compatibility.
266 fn pass_argument<'x, 'y>(
268 caller_args: &mut impl Iterator<
269 Item = (&'x OpTy<'tcx, M::Provenance>, &'y ArgAbi<'tcx, Ty<'tcx>>),
271 callee_abi: &ArgAbi<'tcx, Ty<'tcx>>,
272 callee_arg: &PlaceTy<'tcx, M::Provenance>,
273 ) -> InterpResult<'tcx>
278 if matches!(callee_abi.mode, PassMode::Ignore) {
279 // This one is skipped.
282 // Find next caller arg.
283 let (caller_arg, caller_abi) = caller_args.next().ok_or_else(|| {
284 err_ub_format!("calling a function with fewer arguments than it requires")
287 if !Self::check_argument_compat(caller_abi, callee_abi) {
289 "calling a function with argument of type {:?} passing data of type {:?}",
290 callee_arg.layout.ty,
294 // Special handling for unsized parameters.
295 if caller_arg.layout.is_unsized() {
296 // `check_argument_compat` ensures that both have the same type, so we know they will use the metadata the same way.
297 assert_eq!(caller_arg.layout.ty, callee_arg.layout.ty);
298 // We have to properly pre-allocate the memory for the callee.
299 // So let's tear down some wrappers.
300 // This all has to be in memory, there are no immediate unsized values.
301 let src = caller_arg.assert_mem_place();
302 // The destination cannot be one of these "spread args".
303 let (dest_frame, dest_local) = callee_arg.assert_local();
304 // We are just initializing things, so there can't be anything here yet.
306 *self.local_to_op(&self.stack()[dest_frame], dest_local, None)?,
307 Operand::Immediate(Immediate::Uninit)
309 // Allocate enough memory to hold `src`.
310 let Some((size, align)) = self.size_and_align_of_mplace(&src)? else {
311 span_bug!(self.cur_span(), "unsized fn arg with `extern` type tail should not be allowed")
313 let ptr = self.allocate_ptr(size, align, MemoryKind::Stack)?;
315 MPlaceTy::from_aligned_ptr_with_meta(ptr.into(), callee_arg.layout, src.meta);
316 // Update the local to be that new place.
317 *M::access_local_mut(self, dest_frame, dest_local)? = Operand::Indirect(*dest_place);
319 // We allow some transmutes here.
320 // FIXME: Depending on the PassMode, this should reset some padding to uninitialized. (This
321 // is true for all `copy_op`, but there are a lot of special cases for argument passing
323 self.copy_op(&caller_arg, callee_arg, /*allow_transmute*/ true)
326 /// Call this function -- pushing the stack frame and initializing the arguments.
328 /// `caller_fn_abi` is used to determine if all the arguments are passed the proper way.
329 /// However, we also need `caller_abi` to determine if we need to do untupling of arguments.
331 /// `with_caller_location` indicates whether the caller passed a caller location. Miri
332 /// implements caller locations without argument passing, but to match `FnAbi` we need to know
333 /// when those arguments are present.
334 pub(crate) fn eval_fn_call(
336 fn_val: FnVal<'tcx, M::ExtraFnVal>,
337 (caller_abi, caller_fn_abi): (Abi, &FnAbi<'tcx, Ty<'tcx>>),
338 args: &[OpTy<'tcx, M::Provenance>],
339 with_caller_location: bool,
340 destination: &PlaceTy<'tcx, M::Provenance>,
341 target: Option<mir::BasicBlock>,
342 mut unwind: StackPopUnwind,
343 ) -> InterpResult<'tcx> {
344 trace!("eval_fn_call: {:#?}", fn_val);
346 let instance = match fn_val {
347 FnVal::Instance(instance) => instance,
348 FnVal::Other(extra) => {
349 return M::call_extra_fn(
362 ty::InstanceDef::Intrinsic(def_id) => {
363 assert!(self.tcx.is_intrinsic(def_id));
364 // caller_fn_abi is not relevant here, we interpret the arguments directly for each intrinsic.
365 M::call_intrinsic(self, instance, args, destination, target, unwind)
367 ty::InstanceDef::VTableShim(..)
368 | ty::InstanceDef::ReifyShim(..)
369 | ty::InstanceDef::ClosureOnceShim { .. }
370 | ty::InstanceDef::FnPtrShim(..)
371 | ty::InstanceDef::DropGlue(..)
372 | ty::InstanceDef::CloneShim(..)
373 | ty::InstanceDef::Item(_) => {
374 // We need MIR for this fn
375 let Some((body, instance)) =
376 M::find_mir_or_eval_fn(self, instance, caller_abi, args, destination, target, unwind)? else {
380 // Compute callee information using the `instance` returned by
381 // `find_mir_or_eval_fn`.
382 // FIXME: for variadic support, do we have to somehow determine callee's extra_args?
383 let callee_fn_abi = self.fn_abi_of_instance(instance, ty::List::empty())?;
385 if callee_fn_abi.c_variadic || caller_fn_abi.c_variadic {
386 throw_unsup_format!("calling a c-variadic function is not supported");
389 if M::enforce_abi(self) {
390 if caller_fn_abi.conv != callee_fn_abi.conv {
392 "calling a function with calling convention {:?} using calling convention {:?}",
399 if !matches!(unwind, StackPopUnwind::NotAllowed) && !callee_fn_abi.can_unwind {
400 // The callee cannot unwind.
401 unwind = StackPopUnwind::NotAllowed;
404 self.push_stack_frame(
408 StackPopCleanup::Goto { ret: target, unwind },
411 // If an error is raised here, pop the frame again to get an accurate backtrace.
412 // To this end, we wrap it all in a `try` block.
413 let res: InterpResult<'tcx> = try {
415 "caller ABI: {:?}, args: {:#?}",
418 .map(|arg| (arg.layout.ty, format!("{:?}", **arg)))
422 "spread_arg: {:?}, locals: {:#?}",
427 self.layout_of_local(self.frame(), local, None).unwrap().ty
432 // In principle, we have two iterators: Where the arguments come from, and where
435 // For where they come from: If the ABI is RustCall, we untuple the
436 // last incoming argument. These two iterators do not have the same type,
437 // so to keep the code paths uniform we accept an allocation
438 // (for RustCall ABI only).
439 let caller_args: Cow<'_, [OpTy<'tcx, M::Provenance>]> =
440 if caller_abi == Abi::RustCall && !args.is_empty() {
442 let (untuple_arg, args) = args.split_last().unwrap();
443 trace!("eval_fn_call: Will pass last argument by untupling");
446 .map(|a| Ok(a.clone()))
448 (0..untuple_arg.layout.fields.count())
449 .map(|i| self.operand_field(untuple_arg, i)),
451 .collect::<InterpResult<'_, Vec<OpTy<'tcx, M::Provenance>>>>(
458 // If `with_caller_location` is set we pretend there is an extra argument (that
459 // we will not pass).
461 caller_args.len() + if with_caller_location { 1 } else { 0 },
462 caller_fn_abi.args.len(),
463 "mismatch between caller ABI and caller arguments",
465 let mut caller_args = caller_args
467 .zip(caller_fn_abi.args.iter())
468 .filter(|arg_and_abi| !matches!(arg_and_abi.1.mode, PassMode::Ignore));
470 // Now we have to spread them out across the callee's locals,
471 // taking into account the `spread_arg`. If we could write
472 // this is a single iterator (that handles `spread_arg`), then
473 // `pass_argument` would be the loop body. It takes care to
474 // not advance `caller_iter` for ZSTs.
475 let mut callee_args_abis = callee_fn_abi.args.iter();
476 for local in body.args_iter() {
477 let dest = self.eval_place(mir::Place::from(local))?;
478 if Some(local) == body.spread_arg {
480 for i in 0..dest.layout.fields.count() {
481 let dest = self.place_field(&dest, i)?;
482 let callee_abi = callee_args_abis.next().unwrap();
483 self.pass_argument(&mut caller_args, callee_abi, &dest)?;
487 let callee_abi = callee_args_abis.next().unwrap();
488 self.pass_argument(&mut caller_args, callee_abi, &dest)?;
491 // If the callee needs a caller location, pretend we consume one more argument from the ABI.
492 if instance.def.requires_caller_location(*self.tcx) {
493 callee_args_abis.next().unwrap();
495 // Now we should have no more caller args or callee arg ABIs
497 callee_args_abis.next().is_none(),
498 "mismatch between callee ABI and callee body arguments"
500 if caller_args.next().is_some() {
501 throw_ub_format!("calling a function with more arguments than it expected")
503 // Don't forget to check the return type!
504 if !Self::check_argument_compat(&caller_fn_abi.ret, &callee_fn_abi.ret) {
506 "calling a function with return type {:?} passing \
507 return place of type {:?}",
508 callee_fn_abi.ret.layout.ty,
509 caller_fn_abi.ret.layout.ty,
515 self.stack_mut().pop();
521 // cannot use the shim here, because that will only result in infinite recursion
522 ty::InstanceDef::Virtual(def_id, idx) => {
523 let mut args = args.to_vec();
524 // We have to implement all "object safe receivers". So we have to go search for a
525 // pointer or `dyn Trait` type, but it could be wrapped in newtypes. So recursively
526 // unwrap those newtypes until we are there.
527 let mut receiver = args[0].clone();
528 let receiver_place = loop {
529 match receiver.layout.ty.kind() {
530 ty::Ref(..) | ty::RawPtr(..) => break self.deref_operand(&receiver)?,
531 ty::Dynamic(..) => break receiver.assert_mem_place(), // no immediate unsized values
533 // Not there yet, search for the only non-ZST field.
534 let mut non_zst_field = None;
535 for i in 0..receiver.layout.fields.count() {
536 let field = self.operand_field(&receiver, i)?;
537 if !field.layout.is_zst() {
539 non_zst_field.is_none(),
540 "multiple non-ZST fields in dyn receiver type {}",
543 non_zst_field = Some(field);
546 receiver = non_zst_field.unwrap_or_else(|| {
548 "no non-ZST fields in dyn receiver type {}",
555 // Obtain the underlying trait we are working on.
556 let receiver_tail = self
558 .struct_tail_erasing_lifetimes(receiver_place.layout.ty, self.param_env);
559 let ty::Dynamic(data, ..) = receiver_tail.kind() else {
560 span_bug!(self.cur_span(), "dyanmic call on non-`dyn` type {}", receiver_tail)
563 // Get the required information from the vtable.
564 let vptr = receiver_place.meta.unwrap_meta().to_pointer(self)?;
565 let (dyn_ty, dyn_trait) = self.get_ptr_vtable(vptr)?;
566 if dyn_trait != data.principal() {
568 "`dyn` call on a pointer whose vtable does not match its type"
572 // Now determine the actual method to call. We can do that in two different ways and
573 // compare them to ensure everything fits.
574 let Some(ty::VtblEntry::Method(fn_inst)) = self.get_vtable_entries(vptr)?.get(idx).copied() else {
575 throw_ub_format!("`dyn` call trying to call something that is not a method")
577 if cfg!(debug_assertions) {
580 let trait_def_id = tcx.trait_of_item(def_id).unwrap();
581 let virtual_trait_ref =
582 ty::TraitRef::from_method(tcx, trait_def_id, instance.substs);
585 virtual_trait_ref.self_ty(),
586 "mismatch in underlying dyn trait computation within Miri and MIR building",
588 let existential_trait_ref =
589 ty::ExistentialTraitRef::erase_self_ty(tcx, virtual_trait_ref);
590 let concrete_trait_ref = existential_trait_ref.with_self_ty(tcx, dyn_ty);
592 let concrete_method = Instance::resolve_for_vtable(
596 instance.substs.rebase_onto(tcx, trait_def_id, concrete_trait_ref.substs),
599 assert_eq!(fn_inst, concrete_method);
602 // `*mut receiver_place.layout.ty` is almost the layout that we
603 // want for args[0]: We have to project to field 0 because we want
605 assert!(receiver_place.layout.is_unsized());
606 let receiver_ptr_ty = self.tcx.mk_mut_ptr(receiver_place.layout.ty);
607 let this_receiver_ptr = self.layout_of(receiver_ptr_ty)?.field(self, 0);
608 // Adjust receiver argument.
609 args[0] = OpTy::from(ImmTy::from_immediate(
610 Scalar::from_maybe_pointer(receiver_place.ptr, self).into(),
613 trace!("Patched receiver operand to {:#?}", args[0]);
614 // recurse with concrete function
616 FnVal::Instance(fn_inst),
617 (caller_abi, caller_fn_abi),
619 with_caller_location,
630 place: &PlaceTy<'tcx, M::Provenance>,
631 instance: ty::Instance<'tcx>,
632 target: mir::BasicBlock,
633 unwind: Option<mir::BasicBlock>,
634 ) -> InterpResult<'tcx> {
635 trace!("drop_in_place: {:?},\n {:?}, {:?}", *place, place.layout.ty, instance);
636 // We take the address of the object. This may well be unaligned, which is fine
637 // for us here. However, unaligned accesses will probably make the actual drop
638 // implementation fail -- a problem shared by rustc.
639 let place = self.force_allocation(place)?;
641 let (instance, place) = match place.layout.ty.kind() {
643 // Dropping a trait object. Need to find actual drop fn.
644 let place = self.unpack_dyn_trait(&place)?;
645 let instance = ty::Instance::resolve_drop_in_place(*self.tcx, place.layout.ty);
648 _ => (instance, place),
650 let fn_abi = self.fn_abi_of_instance(instance, ty::List::empty())?;
652 let arg = ImmTy::from_immediate(
654 self.layout_of(self.tcx.mk_mut_ptr(place.layout.ty))?,
656 let ret = MPlaceTy::fake_alloc_zst(self.layout_of(self.tcx.types.unit)?);
659 FnVal::Instance(instance),
666 Some(cleanup) => StackPopUnwind::Cleanup(cleanup),
667 None => StackPopUnwind::Skip,