1 use std::convert::{TryFrom, TryInto};
3 use std::num::NonZeroUsize;
4 use std::time::Duration;
9 use rustc_middle::ty::{self, List, TyCtxt, layout::TyAndLayout};
10 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
11 use rustc_target::abi::{LayoutOf, Size, FieldsShape, Variants};
17 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
19 /// Gets an instance for a path.
20 fn try_resolve_did<'mir, 'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
23 .find(|&&krate| tcx.original_crate_name(krate).as_str() == path[0])
25 let krate = DefId { krate: *krate, index: CRATE_DEF_INDEX };
26 let mut items = tcx.item_children(krate);
27 let mut path_it = path.iter().skip(1).peekable();
29 while let Some(segment) = path_it.next() {
30 for item in mem::replace(&mut items, Default::default()).iter() {
31 if item.ident.name.as_str() == *segment {
32 if path_it.peek().is_none() {
33 return Some(item.res.def_id());
36 items = tcx.item_children(item.res.def_id());
45 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
46 /// Gets an instance for a path.
47 fn resolve_path(&self, path: &[&str]) -> ty::Instance<'tcx> {
48 let did = try_resolve_did(self.eval_context_ref().tcx.tcx, path)
49 .unwrap_or_else(|| panic!("failed to find required Rust item: {:?}", path));
50 ty::Instance::mono(self.eval_context_ref().tcx.tcx, did)
53 /// Evaluates the scalar at the specified path. Returns Some(val)
54 /// if the path could be resolved, and None otherwise
58 ) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
59 let this = self.eval_context_mut();
60 let instance = this.resolve_path(path);
61 let cid = GlobalId { instance, promoted: None };
62 let const_val = this.const_eval_raw(cid)?;
63 let const_val = this.read_scalar(const_val.into())?;
67 /// Helper function to get a `libc` constant as a `Scalar`.
68 fn eval_libc(&mut self, name: &str) -> InterpResult<'tcx, Scalar<Tag>> {
69 self.eval_context_mut()
70 .eval_path_scalar(&["libc", name])?
74 /// Helper function to get a `libc` constant as an `i32`.
75 fn eval_libc_i32(&mut self, name: &str) -> InterpResult<'tcx, i32> {
76 // TODO: Cache the result.
77 self.eval_libc(name)?.to_i32()
80 /// Helper function to get a `windows` constant as a `Scalar`.
81 fn eval_windows(&mut self, module: &str, name: &str) -> InterpResult<'tcx, Scalar<Tag>> {
82 self.eval_context_mut()
83 .eval_path_scalar(&["std", "sys", "windows", module, name])?
87 /// Helper function to get a `windows` constant as an `u64`.
88 fn eval_windows_u64(&mut self, module: &str, name: &str) -> InterpResult<'tcx, u64> {
89 // TODO: Cache the result.
90 self.eval_windows(module, name)?.to_u64()
93 /// Helper function to get the `TyAndLayout` of a `libc` type
94 fn libc_ty_layout(&mut self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
95 let this = self.eval_context_mut();
96 let ty = this.resolve_path(&["libc", name]).ty(*this.tcx, ty::ParamEnv::reveal_all());
100 /// Helper function to get the `TyAndLayout` of a `windows` type
101 fn windows_ty_layout(&mut self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
102 let this = self.eval_context_mut();
103 let ty = this.resolve_path(&["std", "sys", "windows", "c", name]).ty(*this.tcx, ty::ParamEnv::reveal_all());
107 /// Write a 0 of the appropriate size to `dest`.
108 fn write_null(&mut self, dest: PlaceTy<'tcx, Tag>) -> InterpResult<'tcx> {
109 self.eval_context_mut().write_scalar(Scalar::from_int(0, dest.layout.size), dest)
112 /// Test if this immediate equals 0.
113 fn is_null(&self, val: Scalar<Tag>) -> InterpResult<'tcx, bool> {
114 let this = self.eval_context_ref();
115 let null = Scalar::null_ptr(this);
116 this.ptr_eq(val, null)
119 /// Turn a Scalar into an Option<NonNullScalar>
120 fn test_null(&self, val: Scalar<Tag>) -> InterpResult<'tcx, Option<Scalar<Tag>>> {
121 let this = self.eval_context_ref();
122 Ok(if this.is_null(val)? { None } else { Some(val) })
125 /// Get the `Place` for a local
126 fn local_place(&mut self, local: mir::Local) -> InterpResult<'tcx, PlaceTy<'tcx, Tag>> {
127 let this = self.eval_context_mut();
128 let place = mir::Place { local: local, projection: List::empty() };
129 this.eval_place(place)
132 /// Generate some random bytes, and write them to `dest`.
133 fn gen_random(&mut self, ptr: Scalar<Tag>, len: u64) -> InterpResult<'tcx> {
134 // Some programs pass in a null pointer and a length of 0
135 // to their platform's random-generation function (e.g. getrandom())
136 // on Linux. For compatibility with these programs, we don't perform
137 // any additional checks - it's okay if the pointer is invalid,
138 // since we wouldn't actually be writing to it.
142 let this = self.eval_context_mut();
144 let mut data = vec![0; usize::try_from(len).unwrap()];
146 if this.machine.communicate {
147 // Fill the buffer using the host's rng.
148 getrandom::getrandom(&mut data)
149 .map_err(|err| err_unsup_format!("host getrandom failed: {}", err))?;
151 let rng = this.memory.extra.rng.get_mut();
152 rng.fill_bytes(&mut data);
155 this.memory.write_bytes(ptr, data.iter().copied())
158 /// Call a function: Push the stack frame and pass the arguments.
159 /// For now, arguments must be scalars (so that the caller does not have to know the layout).
162 f: ty::Instance<'tcx>,
163 args: &[Immediate<Tag>],
164 dest: Option<PlaceTy<'tcx, Tag>>,
165 stack_pop: StackPopCleanup,
166 ) -> InterpResult<'tcx> {
167 let this = self.eval_context_mut();
170 let mir = &*this.load_mir(f.def, None)?;
171 this.push_stack_frame(f, mir, dest, stack_pop)?;
173 // Initialize arguments.
174 let mut callee_args = this.frame().body.args_iter();
176 let callee_arg = this.local_place(
177 callee_args.next().expect("callee has fewer arguments than expected"),
179 this.write_immediate(*arg, callee_arg)?;
181 callee_args.next().expect_none("callee has more arguments than expected");
186 /// Visits the memory covered by `place`, sensitive to freezing: the 3rd parameter
187 /// will be true if this is frozen, false if this is in an `UnsafeCell`.
188 fn visit_freeze_sensitive(
190 place: MPlaceTy<'tcx, Tag>,
192 mut action: impl FnMut(Pointer<Tag>, Size, bool) -> InterpResult<'tcx>,
193 ) -> InterpResult<'tcx> {
194 let this = self.eval_context_ref();
195 trace!("visit_frozen(place={:?}, size={:?})", *place, size);
198 this.size_and_align_of_mplace(place)?
199 .map(|(size, _)| size)
200 .unwrap_or_else(|| place.layout.size)
202 // Store how far we proceeded into the place so far. Everything to the left of
203 // this offset has already been handled, in the sense that the frozen parts
204 // have had `action` called on them.
205 let mut end_ptr = place.ptr.assert_ptr();
206 // Called when we detected an `UnsafeCell` at the given offset and size.
207 // Calls `action` and advances `end_ptr`.
208 let mut unsafe_cell_action = |unsafe_cell_ptr: Scalar<Tag>, unsafe_cell_size: Size| {
209 let unsafe_cell_ptr = unsafe_cell_ptr.assert_ptr();
210 debug_assert_eq!(unsafe_cell_ptr.alloc_id, end_ptr.alloc_id);
211 debug_assert_eq!(unsafe_cell_ptr.tag, end_ptr.tag);
212 // We assume that we are given the fields in increasing offset order,
213 // and nothing else changes.
214 let unsafe_cell_offset = unsafe_cell_ptr.offset;
215 let end_offset = end_ptr.offset;
216 assert!(unsafe_cell_offset >= end_offset);
217 let frozen_size = unsafe_cell_offset - end_offset;
218 // Everything between the end_ptr and this `UnsafeCell` is frozen.
219 if frozen_size != Size::ZERO {
220 action(end_ptr, frozen_size, /*frozen*/ true)?;
222 // This `UnsafeCell` is NOT frozen.
223 if unsafe_cell_size != Size::ZERO {
224 action(unsafe_cell_ptr, unsafe_cell_size, /*frozen*/ false)?;
226 // Update end end_ptr.
227 end_ptr = unsafe_cell_ptr.wrapping_offset(unsafe_cell_size, this);
233 let mut visitor = UnsafeCellVisitor {
235 unsafe_cell_action: |place| {
236 trace!("unsafe_cell_action on {:?}", place.ptr);
237 // We need a size to go on.
238 let unsafe_cell_size = this
239 .size_and_align_of_mplace(place)?
240 .map(|(size, _)| size)
241 // for extern types, just cover what we can
242 .unwrap_or_else(|| place.layout.size);
243 // Now handle this `UnsafeCell`, unless it is empty.
244 if unsafe_cell_size != Size::ZERO {
245 unsafe_cell_action(place.ptr, unsafe_cell_size)
251 visitor.visit_value(place)?;
253 // The part between the end_ptr and the end of the place is also frozen.
254 // So pretend there is a 0-sized `UnsafeCell` at the end.
255 unsafe_cell_action(place.ptr.ptr_wrapping_offset(size, this), Size::ZERO)?;
259 /// Visiting the memory covered by a `MemPlace`, being aware of
260 /// whether we are inside an `UnsafeCell` or not.
261 struct UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
263 F: FnMut(MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>,
265 ecx: &'ecx MiriEvalContext<'mir, 'tcx>,
266 unsafe_cell_action: F,
269 impl<'ecx, 'mir, 'tcx: 'mir, F> ValueVisitor<'mir, 'tcx, Evaluator<'mir, 'tcx>>
270 for UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
272 F: FnMut(MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>,
274 type V = MPlaceTy<'tcx, Tag>;
277 fn ecx(&self) -> &MiriEvalContext<'mir, 'tcx> {
281 // Hook to detect `UnsafeCell`.
282 fn visit_value(&mut self, v: MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx> {
283 trace!("UnsafeCellVisitor: {:?} {:?}", *v, v.layout.ty);
284 let is_unsafe_cell = match v.layout.ty.kind() {
286 Some(adt.did) == self.ecx.tcx.lang_items().unsafe_cell_type(),
290 // We do not have to recurse further, this is an `UnsafeCell`.
291 (self.unsafe_cell_action)(v)
292 } else if self.ecx.type_is_freeze(v.layout.ty) {
293 // This is `Freeze`, there cannot be an `UnsafeCell`
295 } else if matches!(v.layout.fields, FieldsShape::Union(..)) {
296 // A (non-frozen) union. We fall back to whatever the type says.
297 (self.unsafe_cell_action)(v)
299 // We want to not actually read from memory for this visit. So, before
300 // walking this value, we have to make sure it is not a
301 // `Variants::Multiple`.
302 match v.layout.variants {
303 Variants::Multiple { .. } => {
304 // A multi-variant enum, or generator, or so.
305 // Treat this like a union: without reading from memory,
306 // we cannot determine the variant we are in. Reading from
307 // memory would be subject to Stacked Borrows rules, leading
308 // to all sorts of "funny" recursion.
309 // We only end up here if the type is *not* freeze, so we just call the
310 // `UnsafeCell` action.
311 (self.unsafe_cell_action)(v)
313 Variants::Single { .. } => {
314 // Proceed further, try to find where exactly that `UnsafeCell`
322 // Make sure we visit aggregrates in increasing offset order.
325 place: MPlaceTy<'tcx, Tag>,
326 fields: impl Iterator<Item = InterpResult<'tcx, MPlaceTy<'tcx, Tag>>>,
327 ) -> InterpResult<'tcx> {
328 match place.layout.fields {
329 FieldsShape::Array { .. } => {
330 // For the array layout, we know the iterator will yield sorted elements so
331 // we can avoid the allocation.
332 self.walk_aggregate(place, fields)
334 FieldsShape::Arbitrary { .. } => {
335 // Gather the subplaces and sort them before visiting.
337 fields.collect::<InterpResult<'tcx, Vec<MPlaceTy<'tcx, Tag>>>>()?;
338 places.sort_by_key(|place| place.ptr.assert_ptr().offset);
339 self.walk_aggregate(place, places.into_iter().map(Ok))
341 FieldsShape::Union { .. } | FieldsShape::Primitive => {
343 bug!("unions/primitives are not aggregates we should ever visit")
348 fn visit_union(&mut self, _v: MPlaceTy<'tcx, Tag>, _fields: NonZeroUsize) -> InterpResult<'tcx> {
349 bug!("we should have already handled unions in `visit_value`")
354 // Writes several `ImmTy`s contiguously into memory. This is useful when you have to pack
355 // different values into a struct.
356 fn write_packed_immediates(
358 place: MPlaceTy<'tcx, Tag>,
359 imms: &[ImmTy<'tcx, Tag>],
360 ) -> InterpResult<'tcx> {
361 let this = self.eval_context_mut();
363 let mut offset = Size::from_bytes(0);
366 this.write_immediate_to_mplace(
368 place.offset(offset, MemPlaceMeta::None, imm.layout, &*this.tcx)?,
370 offset += imm.layout.size;
375 /// Helper function used inside the shims of foreign functions to check that isolation is
376 /// disabled. It returns an error using the `name` of the foreign function if this is not the
378 fn check_no_isolation(&self, name: &str) -> InterpResult<'tcx> {
379 if !self.eval_context_ref().machine.communicate {
380 isolation_error(name)?;
385 /// Helper function used inside the shims of foreign functions to assert that the target OS
386 /// is `target_os`. It panics showing a message with the `name` of the foreign function
387 /// if this is not the case.
388 fn assert_target_os(&self, target_os: &str, name: &str) {
390 self.eval_context_ref().tcx.sess.target.target.target_os,
392 "`{}` is only available on the `{}` target OS",
398 /// Get last error variable as a place, lazily allocating thread-local storage for it if
400 fn last_error_place(&mut self) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> {
401 let this = self.eval_context_mut();
402 if let Some(errno_place) = this.active_thread_ref().last_error {
405 // Allocate new place, set initial value to 0.
406 let errno_layout = this.machine.layouts.u32;
407 let errno_place = this.allocate(errno_layout, MiriMemoryKind::Machine.into());
408 this.write_scalar(Scalar::from_u32(0), errno_place.into())?;
409 this.active_thread_mut().last_error = Some(errno_place);
414 /// Sets the last error variable.
415 fn set_last_error(&mut self, scalar: Scalar<Tag>) -> InterpResult<'tcx> {
416 let this = self.eval_context_mut();
417 let errno_place = this.last_error_place()?;
418 this.write_scalar(scalar, errno_place.into())
421 /// Gets the last error variable.
422 fn get_last_error(&mut self) -> InterpResult<'tcx, Scalar<Tag>> {
423 let this = self.eval_context_mut();
424 let errno_place = this.last_error_place()?;
425 this.read_scalar(errno_place.into())?.check_init()
428 /// Sets the last OS error using a `std::io::Error`. This function tries to produce the most
429 /// similar OS error from the `std::io::ErrorKind` and sets it as the last OS error.
430 fn set_last_error_from_io_error(&mut self, e: std::io::Error) -> InterpResult<'tcx> {
431 use std::io::ErrorKind::*;
432 let this = self.eval_context_mut();
433 let target = &this.tcx.sess.target.target;
434 let target_os = &target.target_os;
435 let last_error = if target.options.target_family == Some("unix".to_owned()) {
436 this.eval_libc(match e.kind() {
437 ConnectionRefused => "ECONNREFUSED",
438 ConnectionReset => "ECONNRESET",
439 PermissionDenied => "EPERM",
440 BrokenPipe => "EPIPE",
441 NotConnected => "ENOTCONN",
442 ConnectionAborted => "ECONNABORTED",
443 AddrNotAvailable => "EADDRNOTAVAIL",
444 AddrInUse => "EADDRINUSE",
445 NotFound => "ENOENT",
446 Interrupted => "EINTR",
447 InvalidInput => "EINVAL",
448 TimedOut => "ETIMEDOUT",
449 AlreadyExists => "EEXIST",
450 WouldBlock => "EWOULDBLOCK",
452 throw_unsup_format!("io error {} cannot be transformed into a raw os error", e)
455 } else if target_os == "windows" {
456 // FIXME: we have to finish implementing the Windows equivalent of this.
457 this.eval_windows("c", match e.kind() {
458 NotFound => "ERROR_FILE_NOT_FOUND",
459 _ => throw_unsup_format!("io error {} cannot be transformed into a raw os error", e)
462 throw_unsup_format!("setting the last OS error from an io::Error is unsupported for {}.", target_os)
464 this.set_last_error(last_error)
467 /// Helper function that consumes an `std::io::Result<T>` and returns an
468 /// `InterpResult<'tcx,T>::Ok` instead. In case the result is an error, this function returns
469 /// `Ok(-1)` and sets the last OS error accordingly.
471 /// This function uses `T: From<i32>` instead of `i32` directly because some IO related
472 /// functions return different integer types (like `read`, that returns an `i64`).
473 fn try_unwrap_io_result<T: From<i32>>(
475 result: std::io::Result<T>,
476 ) -> InterpResult<'tcx, T> {
480 self.eval_context_mut().set_last_error_from_io_error(e)?;
486 fn read_scalar_at_offset(
490 layout: TyAndLayout<'tcx>,
491 ) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
492 let this = self.eval_context_ref();
493 let op_place = this.deref_operand(op)?;
494 let offset = Size::from_bytes(offset);
495 // Ensure that the following read at an offset is within bounds
496 assert!(op_place.layout.size >= offset + layout.size);
497 let value_place = op_place.offset(offset, MemPlaceMeta::None, layout, this)?;
498 this.read_scalar(value_place.into())
501 fn write_scalar_at_offset(
505 value: impl Into<ScalarMaybeUninit<Tag>>,
506 layout: TyAndLayout<'tcx>,
507 ) -> InterpResult<'tcx, ()> {
508 let this = self.eval_context_mut();
509 let op_place = this.deref_operand(op)?;
510 let offset = Size::from_bytes(offset);
511 // Ensure that the following read at an offset is within bounds
512 assert!(op_place.layout.size >= offset + layout.size);
513 let value_place = op_place.offset(offset, MemPlaceMeta::None, layout, this)?;
514 this.write_scalar(value, value_place.into())
517 /// Parse a `timespec` struct and return it as a `std::time::Duration`. It returns `None`
518 /// if the value in the `timespec` struct is invalid. Some libc functions will return
519 /// `EINVAL` in this case.
522 timespec_ptr_op: OpTy<'tcx, Tag>,
523 ) -> InterpResult<'tcx, Option<Duration>> {
524 let this = self.eval_context_mut();
525 let tp = this.deref_operand(timespec_ptr_op)?;
526 let seconds_place = this.mplace_field(tp, 0)?;
527 let seconds_scalar = this.read_scalar(seconds_place.into())?;
528 let seconds = seconds_scalar.to_machine_isize(this)?;
529 let nanoseconds_place = this.mplace_field(tp, 1)?;
530 let nanoseconds_scalar = this.read_scalar(nanoseconds_place.into())?;
531 let nanoseconds = nanoseconds_scalar.to_machine_isize(this)?;
534 // tv_sec must be non-negative.
535 let seconds: u64 = seconds.try_into().ok()?;
536 // tv_nsec must be non-negative.
537 let nanoseconds: u32 = nanoseconds.try_into().ok()?;
538 if nanoseconds >= 1_000_000_000 {
539 // tv_nsec must not be greater than 999,999,999.
542 Duration::new(seconds, nanoseconds)
547 /// Check that the number of args is what we expect.
548 pub fn check_arg_count<'a, 'tcx, const N: usize>(args: &'a [OpTy<'tcx, Tag>]) -> InterpResult<'tcx, &'a [OpTy<'tcx, Tag>; N]>
549 where &'a [OpTy<'tcx, Tag>; N]: TryFrom<&'a [OpTy<'tcx, Tag>]> {
550 if let Ok(ops) = args.try_into() {
553 throw_ub_format!("incorrect number of arguments: got {}, expected {}", args.len(), N)
556 pub fn isolation_error(name: &str) -> InterpResult<'static> {
557 throw_machine_stop!(TerminationInfo::UnsupportedInIsolation(format!(
558 "`{}` not available when isolation is enabled",
563 pub fn immty_from_int_checked<'tcx>(
564 int: impl Into<i128>,
565 layout: TyAndLayout<'tcx>,
566 ) -> InterpResult<'tcx, ImmTy<'tcx, Tag>> {
567 let int = int.into();
568 Ok(ImmTy::try_from_int(int, layout).ok_or_else(|| {
569 err_unsup_format!("signed value {:#x} does not fit in {} bits", int, layout.size.bits())
573 pub fn immty_from_uint_checked<'tcx>(
574 int: impl Into<u128>,
575 layout: TyAndLayout<'tcx>,
576 ) -> InterpResult<'tcx, ImmTy<'tcx, Tag>> {
577 let int = int.into();
578 Ok(ImmTy::try_from_uint(int, layout).ok_or_else(|| {
579 err_unsup_format!("unsigned value {:#x} does not fit in {} bits", int, layout.size.bits())