4 use std::num::NonZeroUsize;
5 use std::time::Duration;
9 use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX};
10 use rustc_middle::mir;
11 use rustc_middle::ty::{
13 layout::{LayoutOf, TyAndLayout},
16 use rustc_span::{def_id::CrateNum, sym, Span, Symbol};
17 use rustc_target::abi::{Align, FieldsShape, Size, Variants};
18 use rustc_target::spec::abi::Abi;
24 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
26 const UNIX_IO_ERROR_TABLE: &[(std::io::ErrorKind, &str)] = {
27 use std::io::ErrorKind::*;
29 (ConnectionRefused, "ECONNREFUSED"),
30 (ConnectionReset, "ECONNRESET"),
31 (PermissionDenied, "EPERM"),
32 (BrokenPipe, "EPIPE"),
33 (NotConnected, "ENOTCONN"),
34 (ConnectionAborted, "ECONNABORTED"),
35 (AddrNotAvailable, "EADDRNOTAVAIL"),
36 (AddrInUse, "EADDRINUSE"),
38 (Interrupted, "EINTR"),
39 (InvalidInput, "EINVAL"),
40 (TimedOut, "ETIMEDOUT"),
41 (AlreadyExists, "EEXIST"),
42 (WouldBlock, "EWOULDBLOCK"),
43 (DirectoryNotEmpty, "ENOTEMPTY"),
47 /// Gets an instance for a path.
48 fn try_resolve_did<'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option<DefId> {
49 tcx.crates(()).iter().find(|&&krate| tcx.crate_name(krate).as_str() == path[0]).and_then(
51 let krate = DefId { krate: *krate, index: CRATE_DEF_INDEX };
52 let mut items = tcx.module_children(krate);
53 let mut path_it = path.iter().skip(1).peekable();
55 while let Some(segment) = path_it.next() {
56 for item in mem::take(&mut items).iter() {
57 if item.ident.name.as_str() == *segment {
58 if path_it.peek().is_none() {
59 return Some(item.res.def_id());
62 items = tcx.module_children(item.res.def_id());
72 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
73 /// Gets an instance for a path; fails gracefully if the path does not exist.
74 fn try_resolve_path(&self, path: &[&str]) -> Option<ty::Instance<'tcx>> {
75 let did = try_resolve_did(self.eval_context_ref().tcx.tcx, path)?;
76 Some(ty::Instance::mono(self.eval_context_ref().tcx.tcx, did))
79 /// Gets an instance for a path.
80 fn resolve_path(&self, path: &[&str]) -> ty::Instance<'tcx> {
81 self.try_resolve_path(path)
82 .unwrap_or_else(|| panic!("failed to find required Rust item: {:?}", path))
85 /// Evaluates the scalar at the specified path. Returns Some(val)
86 /// if the path could be resolved, and None otherwise
87 fn eval_path_scalar(&self, path: &[&str]) -> InterpResult<'tcx, Scalar<Tag>> {
88 let this = self.eval_context_ref();
89 let instance = this.resolve_path(path);
90 let cid = GlobalId { instance, promoted: None };
91 let const_val = this.eval_to_allocation(cid)?;
92 let const_val = this.read_scalar(&const_val.into())?;
93 const_val.check_init()
96 /// Helper function to get a `libc` constant as a `Scalar`.
97 fn eval_libc(&self, name: &str) -> InterpResult<'tcx, Scalar<Tag>> {
98 self.eval_path_scalar(&["libc", name])
101 /// Helper function to get a `libc` constant as an `i32`.
102 fn eval_libc_i32(&self, name: &str) -> InterpResult<'tcx, i32> {
103 // TODO: Cache the result.
104 self.eval_libc(name)?.to_i32()
107 /// Helper function to get a `windows` constant as a `Scalar`.
108 fn eval_windows(&self, module: &str, name: &str) -> InterpResult<'tcx, Scalar<Tag>> {
109 self.eval_context_ref().eval_path_scalar(&["std", "sys", "windows", module, name])
112 /// Helper function to get a `windows` constant as a `u64`.
113 fn eval_windows_u64(&self, module: &str, name: &str) -> InterpResult<'tcx, u64> {
114 // TODO: Cache the result.
115 self.eval_windows(module, name)?.to_u64()
118 /// Helper function to get the `TyAndLayout` of a `libc` type
119 fn libc_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
120 let this = self.eval_context_ref();
121 let ty = this.resolve_path(&["libc", name]).ty(*this.tcx, ty::ParamEnv::reveal_all());
125 /// Helper function to get the `TyAndLayout` of a `windows` type
126 fn windows_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> {
127 let this = self.eval_context_ref();
129 .resolve_path(&["std", "sys", "windows", "c", name])
130 .ty(*this.tcx, ty::ParamEnv::reveal_all());
134 /// Project to the given *named* field of the mplace (which must be a struct or union type).
135 fn mplace_field_named(
137 mplace: &MPlaceTy<'tcx, Tag>,
139 ) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> {
140 let this = self.eval_context_ref();
141 let adt = mplace.layout.ty.ty_adt_def().unwrap();
142 for (idx, field) in adt.non_enum_variant().fields.iter().enumerate() {
143 if field.name.as_str() == name {
144 return this.mplace_field(mplace, idx);
147 bug!("No field named {} in type {}", name, mplace.layout.ty);
150 /// Write an int of the appropriate size to `dest`. The target type may be signed or unsigned,
151 /// we try to do the right thing anyway. `i128` can fit all integer types except for `u128` so
152 /// this method is fine for almost all integer types.
153 fn write_int(&mut self, i: impl Into<i128>, dest: &PlaceTy<'tcx, Tag>) -> InterpResult<'tcx> {
154 assert!(dest.layout.abi.is_scalar(), "write_int on non-scalar type {}", dest.layout.ty);
155 let val = if dest.layout.abi.is_signed() {
156 Scalar::from_int(i, dest.layout.size)
158 Scalar::from_uint(u64::try_from(i.into()).unwrap(), dest.layout.size)
160 self.eval_context_mut().write_scalar(val, dest)
163 /// Write the first N fields of the given place.
167 dest: &MPlaceTy<'tcx, Tag>,
168 ) -> InterpResult<'tcx> {
169 let this = self.eval_context_mut();
170 for (idx, &val) in values.iter().enumerate() {
171 let field = this.mplace_field(dest, idx)?;
172 this.write_int(val, &field.into())?;
177 /// Write the given fields of the given place.
178 fn write_int_fields_named(
180 values: &[(&str, i128)],
181 dest: &MPlaceTy<'tcx, Tag>,
182 ) -> InterpResult<'tcx> {
183 let this = self.eval_context_mut();
184 for &(name, val) in values.iter() {
185 let field = this.mplace_field_named(dest, name)?;
186 this.write_int(val, &field.into())?;
191 /// Write a 0 of the appropriate size to `dest`.
192 fn write_null(&mut self, dest: &PlaceTy<'tcx, Tag>) -> InterpResult<'tcx> {
193 self.write_int(0, dest)
196 /// Test if this pointer equals 0.
197 fn ptr_is_null(&self, ptr: Pointer<Option<Tag>>) -> InterpResult<'tcx, bool> {
198 let this = self.eval_context_ref();
199 let null = Scalar::null_ptr(this);
200 this.ptr_eq(Scalar::from_maybe_pointer(ptr, this), null)
203 /// Get the `Place` for a local
204 fn local_place(&mut self, local: mir::Local) -> InterpResult<'tcx, PlaceTy<'tcx, Tag>> {
205 let this = self.eval_context_mut();
206 let place = mir::Place { local, projection: List::empty() };
207 this.eval_place(place)
210 /// Generate some random bytes, and write them to `dest`.
211 fn gen_random(&mut self, ptr: Pointer<Option<Tag>>, len: u64) -> InterpResult<'tcx> {
212 // Some programs pass in a null pointer and a length of 0
213 // to their platform's random-generation function (e.g. getrandom())
214 // on Linux. For compatibility with these programs, we don't perform
215 // any additional checks - it's okay if the pointer is invalid,
216 // since we wouldn't actually be writing to it.
220 let this = self.eval_context_mut();
222 let mut data = vec![0; usize::try_from(len).unwrap()];
224 if this.machine.communicate() {
225 // Fill the buffer using the host's rng.
226 getrandom::getrandom(&mut data)
227 .map_err(|err| err_unsup_format!("host getrandom failed: {}", err))?;
229 let rng = this.machine.rng.get_mut();
230 rng.fill_bytes(&mut data);
233 this.write_bytes_ptr(ptr, data.iter().copied())
236 /// Call a function: Push the stack frame and pass the arguments.
237 /// For now, arguments must be scalars (so that the caller does not have to know the layout).
240 f: ty::Instance<'tcx>,
242 args: &[Immediate<Tag>],
243 dest: &PlaceTy<'tcx, Tag>,
244 stack_pop: StackPopCleanup,
245 ) -> InterpResult<'tcx> {
246 let this = self.eval_context_mut();
247 let param_env = ty::ParamEnv::reveal_all(); // in Miri this is always the param_env we use... and this.param_env is private.
248 let callee_abi = f.ty(*this.tcx, param_env).fn_sig(*this.tcx).abi();
249 if this.machine.enforce_abi && callee_abi != caller_abi {
251 "calling a function with ABI {} using caller ABI {}",
258 let mir = &*this.load_mir(f.def, None)?;
259 this.push_stack_frame(f, mir, dest, stack_pop)?;
261 // Initialize arguments.
262 let mut callee_args = this.frame().body.args_iter();
264 let callee_arg = this.local_place(
267 .ok_or_else(|| err_ub_format!("callee has fewer arguments than expected"))?,
269 this.write_immediate(*arg, &callee_arg)?;
271 if callee_args.next().is_some() {
272 throw_ub_format!("callee has more arguments than expected");
278 /// Visits the memory covered by `place`, sensitive to freezing: the 2nd parameter
279 /// of `action` will be true if this is frozen, false if this is in an `UnsafeCell`.
280 /// The range is relative to `place`.
281 fn visit_freeze_sensitive(
283 place: &MPlaceTy<'tcx, Tag>,
285 mut action: impl FnMut(AllocRange, bool) -> InterpResult<'tcx>,
286 ) -> InterpResult<'tcx> {
287 let this = self.eval_context_ref();
288 trace!("visit_frozen(place={:?}, size={:?})", *place, size);
291 this.size_and_align_of_mplace(place)?
292 .map(|(size, _)| size)
293 .unwrap_or_else(|| place.layout.size)
295 // Store how far we proceeded into the place so far. Everything to the left of
296 // this offset has already been handled, in the sense that the frozen parts
297 // have had `action` called on them.
298 let start_addr = place.ptr.addr();
299 let mut cur_addr = start_addr;
300 // Called when we detected an `UnsafeCell` at the given offset and size.
301 // Calls `action` and advances `cur_ptr`.
302 let mut unsafe_cell_action = |unsafe_cell_ptr: &Pointer<Option<Tag>>,
303 unsafe_cell_size: Size| {
304 // We assume that we are given the fields in increasing offset order,
305 // and nothing else changes.
306 let unsafe_cell_addr = unsafe_cell_ptr.addr();
307 assert!(unsafe_cell_addr >= cur_addr);
308 let frozen_size = unsafe_cell_addr - cur_addr;
309 // Everything between the cur_ptr and this `UnsafeCell` is frozen.
310 if frozen_size != Size::ZERO {
311 action(alloc_range(cur_addr - start_addr, frozen_size), /*frozen*/ true)?;
313 cur_addr += frozen_size;
314 // This `UnsafeCell` is NOT frozen.
315 if unsafe_cell_size != Size::ZERO {
317 alloc_range(cur_addr - start_addr, unsafe_cell_size),
321 cur_addr += unsafe_cell_size;
327 let mut visitor = UnsafeCellVisitor {
329 unsafe_cell_action: |place| {
330 trace!("unsafe_cell_action on {:?}", place.ptr);
331 // We need a size to go on.
332 let unsafe_cell_size = this
333 .size_and_align_of_mplace(place)?
334 .map(|(size, _)| size)
335 // for extern types, just cover what we can
336 .unwrap_or_else(|| place.layout.size);
337 // Now handle this `UnsafeCell`, unless it is empty.
338 if unsafe_cell_size != Size::ZERO {
339 unsafe_cell_action(&place.ptr, unsafe_cell_size)
345 visitor.visit_value(place)?;
347 // The part between the end_ptr and the end of the place is also frozen.
348 // So pretend there is a 0-sized `UnsafeCell` at the end.
349 unsafe_cell_action(&place.ptr.offset(size, this)?, Size::ZERO)?;
353 /// Visiting the memory covered by a `MemPlace`, being aware of
354 /// whether we are inside an `UnsafeCell` or not.
355 struct UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
357 F: FnMut(&MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>,
359 ecx: &'ecx MiriEvalContext<'mir, 'tcx>,
360 unsafe_cell_action: F,
363 impl<'ecx, 'mir, 'tcx: 'mir, F> ValueVisitor<'mir, 'tcx, Evaluator<'mir, 'tcx>>
364 for UnsafeCellVisitor<'ecx, 'mir, 'tcx, F>
366 F: FnMut(&MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>,
368 type V = MPlaceTy<'tcx, Tag>;
371 fn ecx(&self) -> &MiriEvalContext<'mir, 'tcx> {
375 // Hook to detect `UnsafeCell`.
376 fn visit_value(&mut self, v: &MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx> {
377 trace!("UnsafeCellVisitor: {:?} {:?}", *v, v.layout.ty);
378 let is_unsafe_cell = match v.layout.ty.kind() {
380 Some(adt.did()) == self.ecx.tcx.lang_items().unsafe_cell_type(),
384 // We do not have to recurse further, this is an `UnsafeCell`.
385 (self.unsafe_cell_action)(v)
386 } else if self.ecx.type_is_freeze(v.layout.ty) {
387 // This is `Freeze`, there cannot be an `UnsafeCell`
389 } else if matches!(v.layout.fields, FieldsShape::Union(..)) {
390 // A (non-frozen) union. We fall back to whatever the type says.
391 (self.unsafe_cell_action)(v)
393 // We want to not actually read from memory for this visit. So, before
394 // walking this value, we have to make sure it is not a
395 // `Variants::Multiple`.
396 match v.layout.variants {
397 Variants::Multiple { .. } => {
398 // A multi-variant enum, or generator, or so.
399 // Treat this like a union: without reading from memory,
400 // we cannot determine the variant we are in. Reading from
401 // memory would be subject to Stacked Borrows rules, leading
402 // to all sorts of "funny" recursion.
403 // We only end up here if the type is *not* freeze, so we just call the
404 // `UnsafeCell` action.
405 (self.unsafe_cell_action)(v)
407 Variants::Single { .. } => {
408 // Proceed further, try to find where exactly that `UnsafeCell`
416 // Make sure we visit aggregrates in increasing offset order.
419 place: &MPlaceTy<'tcx, Tag>,
420 fields: impl Iterator<Item = InterpResult<'tcx, MPlaceTy<'tcx, Tag>>>,
421 ) -> InterpResult<'tcx> {
422 match place.layout.fields {
423 FieldsShape::Array { .. } => {
424 // For the array layout, we know the iterator will yield sorted elements so
425 // we can avoid the allocation.
426 self.walk_aggregate(place, fields)
428 FieldsShape::Arbitrary { .. } => {
429 // Gather the subplaces and sort them before visiting.
431 fields.collect::<InterpResult<'tcx, Vec<MPlaceTy<'tcx, Tag>>>>()?;
432 // we just compare offsets, the abs. value never matters
433 places.sort_by_key(|place| place.ptr.addr());
434 self.walk_aggregate(place, places.into_iter().map(Ok))
436 FieldsShape::Union { .. } | FieldsShape::Primitive => {
438 bug!("unions/primitives are not aggregates we should ever visit")
445 _v: &MPlaceTy<'tcx, Tag>,
446 _fields: NonZeroUsize,
447 ) -> InterpResult<'tcx> {
448 bug!("we should have already handled unions in `visit_value`")
453 /// Helper function used inside the shims of foreign functions to check that isolation is
454 /// disabled. It returns an error using the `name` of the foreign function if this is not the
456 fn check_no_isolation(&self, name: &str) -> InterpResult<'tcx> {
457 if !self.eval_context_ref().machine.communicate() {
458 self.reject_in_isolation(name, RejectOpWith::Abort)?;
463 /// Helper function used inside the shims of foreign functions which reject the op
464 /// when isolation is enabled. It is used to print a warning/backtrace about the rejection.
465 fn reject_in_isolation(&self, op_name: &str, reject_with: RejectOpWith) -> InterpResult<'tcx> {
466 let this = self.eval_context_ref();
468 RejectOpWith::Abort => isolation_abort_error(op_name),
469 RejectOpWith::WarningWithoutBacktrace => {
472 .warn(&format!("{} was made to return an error due to isolation", op_name));
475 RejectOpWith::Warning => {
476 register_diagnostic(NonHaltingDiagnostic::RejectedIsolatedOp(op_name.to_string()));
479 RejectOpWith::NoWarning => Ok(()), // no warning
483 /// Helper function used inside the shims of foreign functions to assert that the target OS
484 /// is `target_os`. It panics showing a message with the `name` of the foreign function
485 /// if this is not the case.
486 fn assert_target_os(&self, target_os: &str, name: &str) {
488 self.eval_context_ref().tcx.sess.target.os,
490 "`{}` is only available on the `{}` target OS",
496 /// Get last error variable as a place, lazily allocating thread-local storage for it if
498 fn last_error_place(&mut self) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> {
499 let this = self.eval_context_mut();
500 if let Some(errno_place) = this.active_thread_ref().last_error {
503 // Allocate new place, set initial value to 0.
504 let errno_layout = this.machine.layouts.u32;
505 let errno_place = this.allocate(errno_layout, MiriMemoryKind::Machine.into())?;
506 this.write_scalar(Scalar::from_u32(0), &errno_place.into())?;
507 this.active_thread_mut().last_error = Some(errno_place);
512 /// Sets the last error variable.
513 fn set_last_error(&mut self, scalar: Scalar<Tag>) -> InterpResult<'tcx> {
514 let this = self.eval_context_mut();
515 let errno_place = this.last_error_place()?;
516 this.write_scalar(scalar, &errno_place.into())
519 /// Gets the last error variable.
520 fn get_last_error(&mut self) -> InterpResult<'tcx, Scalar<Tag>> {
521 let this = self.eval_context_mut();
522 let errno_place = this.last_error_place()?;
523 this.read_scalar(&errno_place.into())?.check_init()
526 /// This function tries to produce the most similar OS error from the `std::io::ErrorKind`
527 /// as a platform-specific errnum.
528 fn io_error_to_errnum(&self, err_kind: std::io::ErrorKind) -> InterpResult<'tcx, Scalar<Tag>> {
529 let this = self.eval_context_ref();
530 let target = &this.tcx.sess.target;
531 if target.families.iter().any(|f| f == "unix") {
532 for &(kind, name) in UNIX_IO_ERROR_TABLE {
533 if err_kind == kind {
534 return this.eval_libc(name);
537 throw_unsup_format!("io error {:?} cannot be translated into a raw os error", err_kind)
538 } else if target.families.iter().any(|f| f == "windows") {
539 // FIXME: we have to finish implementing the Windows equivalent of this.
540 use std::io::ErrorKind::*;
544 NotFound => "ERROR_FILE_NOT_FOUND",
545 PermissionDenied => "ERROR_ACCESS_DENIED",
548 "io error {:?} cannot be translated into a raw os error",
555 "converting io::Error into errnum is unsupported for OS {}",
561 /// The inverse of `io_error_to_errnum`.
562 fn errnum_to_io_error(&self, errnum: Scalar<Tag>) -> InterpResult<'tcx, std::io::ErrorKind> {
563 let this = self.eval_context_ref();
564 let target = &this.tcx.sess.target;
565 if target.families.iter().any(|f| f == "unix") {
566 let errnum = errnum.to_i32()?;
567 for &(kind, name) in UNIX_IO_ERROR_TABLE {
568 if errnum == this.eval_libc_i32(name)? {
572 throw_unsup_format!("raw errnum {:?} cannot be translated into io::Error", errnum)
575 "converting errnum into io::Error is unsupported for OS {}",
581 /// Sets the last OS error using a `std::io::ErrorKind`.
582 fn set_last_error_from_io_error(&mut self, err_kind: std::io::ErrorKind) -> InterpResult<'tcx> {
583 self.set_last_error(self.io_error_to_errnum(err_kind)?)
586 /// Helper function that consumes an `std::io::Result<T>` and returns an
587 /// `InterpResult<'tcx,T>::Ok` instead. In case the result is an error, this function returns
588 /// `Ok(-1)` and sets the last OS error accordingly.
590 /// This function uses `T: From<i32>` instead of `i32` directly because some IO related
591 /// functions return different integer types (like `read`, that returns an `i64`).
592 fn try_unwrap_io_result<T: From<i32>>(
594 result: std::io::Result<T>,
595 ) -> InterpResult<'tcx, T> {
599 self.eval_context_mut().set_last_error_from_io_error(e.kind())?;
605 /// Calculates the MPlaceTy given the offset and layout of an access on an operand
606 fn deref_operand_and_offset(
608 op: &OpTy<'tcx, Tag>,
610 layout: TyAndLayout<'tcx>,
611 ) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> {
612 let this = self.eval_context_ref();
613 let op_place = this.deref_operand(op)?;
614 let offset = Size::from_bytes(offset);
616 // Ensure that the access is within bounds.
617 assert!(op_place.layout.size >= offset + layout.size);
618 let value_place = op_place.offset(offset, MemPlaceMeta::None, layout, this)?;
622 fn read_scalar_at_offset(
624 op: &OpTy<'tcx, Tag>,
626 layout: TyAndLayout<'tcx>,
627 ) -> InterpResult<'tcx, ScalarMaybeUninit<Tag>> {
628 let this = self.eval_context_ref();
629 let value_place = this.deref_operand_and_offset(op, offset, layout)?;
630 this.read_scalar(&value_place.into())
633 fn write_scalar_at_offset(
635 op: &OpTy<'tcx, Tag>,
637 value: impl Into<ScalarMaybeUninit<Tag>>,
638 layout: TyAndLayout<'tcx>,
639 ) -> InterpResult<'tcx, ()> {
640 let this = self.eval_context_mut();
641 let value_place = this.deref_operand_and_offset(op, offset, layout)?;
642 this.write_scalar(value, &value_place.into())
645 /// Parse a `timespec` struct and return it as a `std::time::Duration`. It returns `None`
646 /// if the value in the `timespec` struct is invalid. Some libc functions will return
647 /// `EINVAL` in this case.
648 fn read_timespec(&mut self, tp: &MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx, Option<Duration>> {
649 let this = self.eval_context_mut();
650 let seconds_place = this.mplace_field(tp, 0)?;
651 let seconds_scalar = this.read_scalar(&seconds_place.into())?;
652 let seconds = seconds_scalar.to_machine_isize(this)?;
653 let nanoseconds_place = this.mplace_field(tp, 1)?;
654 let nanoseconds_scalar = this.read_scalar(&nanoseconds_place.into())?;
655 let nanoseconds = nanoseconds_scalar.to_machine_isize(this)?;
658 // tv_sec must be non-negative.
659 let seconds: u64 = seconds.try_into().ok()?;
660 // tv_nsec must be non-negative.
661 let nanoseconds: u32 = nanoseconds.try_into().ok()?;
662 if nanoseconds >= 1_000_000_000 {
663 // tv_nsec must not be greater than 999,999,999.
666 Duration::new(seconds, nanoseconds)
670 fn read_c_str<'a>(&'a self, ptr: Pointer<Option<Tag>>) -> InterpResult<'tcx, &'a [u8]>
675 let this = self.eval_context_ref();
676 let size1 = Size::from_bytes(1);
678 // Step 1: determine the length.
679 let mut len = Size::ZERO;
681 // FIXME: We are re-getting the allocation each time around the loop.
682 // Would be nice if we could somehow "extend" an existing AllocRange.
683 let alloc = this.get_ptr_alloc(ptr.offset(len, this)?, size1, Align::ONE)?.unwrap(); // not a ZST, so we will get a result
684 let byte = alloc.read_integer(Size::ZERO, size1)?.to_u8()?;
692 // Step 2: get the bytes.
693 this.read_bytes_ptr(ptr, len)
696 fn read_wide_str(&self, mut ptr: Pointer<Option<Tag>>) -> InterpResult<'tcx, Vec<u16>> {
697 let this = self.eval_context_ref();
698 let size2 = Size::from_bytes(2);
699 let align2 = Align::from_bytes(2).unwrap();
701 let mut wchars = Vec::new();
703 // FIXME: We are re-getting the allocation each time around the loop.
704 // Would be nice if we could somehow "extend" an existing AllocRange.
705 let alloc = this.get_ptr_alloc(ptr, size2, align2)?.unwrap(); // not a ZST, so we will get a result
706 let wchar = alloc.read_integer(Size::ZERO, size2)?.to_u16()?;
711 ptr = ptr.offset(size2, this)?;
718 /// Check that the ABI is what we expect.
719 fn check_abi<'a>(&self, abi: Abi, exp_abi: Abi) -> InterpResult<'a, ()> {
720 if self.eval_context_ref().machine.enforce_abi && abi != exp_abi {
722 "calling a function with ABI {} using caller ABI {}",
730 fn frame_in_std(&self) -> bool {
731 let this = self.eval_context_ref();
732 this.tcx.lang_items().start_fn().map_or(false, |start_fn| {
733 this.tcx.def_path(this.frame().instance.def_id()).krate
734 == this.tcx.def_path(start_fn).krate
738 /// Handler that should be called when unsupported functionality is encountered.
739 /// This function will either panic within the context of the emulated application
740 /// or return an error in the Miri process context
742 /// Return value of `Ok(bool)` indicates whether execution should continue.
743 fn handle_unsupported<S: AsRef<str>>(&mut self, error_msg: S) -> InterpResult<'tcx, ()> {
744 let this = self.eval_context_mut();
745 if this.machine.panic_on_unsupported {
746 // message is slightly different here to make automated analysis easier
747 let error_msg = format!("unsupported Miri functionality: {}", error_msg.as_ref());
748 this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?;
751 throw_unsup_format!("{}", error_msg.as_ref());
755 fn check_abi_and_shim_symbol_clash(
760 ) -> InterpResult<'tcx, ()> {
761 self.check_abi(abi, exp_abi)?;
762 if let Some((body, _)) = self.eval_context_mut().lookup_exported_symbol(link_name)? {
763 throw_machine_stop!(TerminationInfo::SymbolShimClashing {
765 span: body.span.data(),
771 fn check_shim<'a, const N: usize>(
776 args: &'a [OpTy<'tcx, Tag>],
777 ) -> InterpResult<'tcx, &'a [OpTy<'tcx, Tag>; N]>
779 &'a [OpTy<'tcx, Tag>; N]: TryFrom<&'a [OpTy<'tcx, Tag>]>,
781 self.check_abi_and_shim_symbol_clash(abi, exp_abi, link_name)?;
782 check_arg_count(args)
785 /// Mark a machine allocation that was just created as immutable.
786 fn mark_immutable(&mut self, mplace: &MemPlace<Tag>) {
787 let this = self.eval_context_mut();
788 // This got just allocated, so there definitely is a pointer here.
789 let provenance = mplace.ptr.into_pointer_or_addr().unwrap().provenance;
790 this.alloc_mark_immutable(provenance.get_alloc_id().unwrap()).unwrap();
793 fn item_link_name(&self, def_id: DefId) -> Symbol {
794 let tcx = self.eval_context_ref().tcx;
795 match tcx.get_attrs(def_id, sym::link_name).filter_map(|a| a.value_str()).next() {
797 None => tcx.item_name(def_id),
802 impl<'mir, 'tcx> Evaluator<'mir, 'tcx> {
803 pub fn current_span(&self) -> CurrentSpan<'_, 'mir, 'tcx> {
804 CurrentSpan { span: None, machine: self }
808 /// A `CurrentSpan` should be created infrequently (ideally once) per interpreter step. It does
809 /// nothing on creation, but when `CurrentSpan::get` is called, searches the current stack for the
810 /// topmost frame which corresponds to a local crate, and returns the current span in that frame.
811 /// The result of that search is cached so that later calls are approximately free.
813 pub struct CurrentSpan<'a, 'mir, 'tcx> {
815 machine: &'a Evaluator<'mir, 'tcx>,
818 impl<'a, 'mir, 'tcx> CurrentSpan<'a, 'mir, 'tcx> {
819 pub fn get(&mut self) -> Span {
820 *self.span.get_or_insert_with(|| Self::current_span(self.machine))
824 fn current_span(machine: &Evaluator<'_, '_>) -> Span {
827 .active_thread_stack()
831 let def_id = frame.instance.def_id();
832 def_id.is_local() || machine.local_crates.contains(&def_id.krate)
834 .map(|frame| frame.current_span())
835 .unwrap_or(rustc_span::DUMMY_SP)
839 /// Check that the number of args is what we expect.
840 pub fn check_arg_count<'a, 'tcx, const N: usize>(
841 args: &'a [OpTy<'tcx, Tag>],
842 ) -> InterpResult<'tcx, &'a [OpTy<'tcx, Tag>; N]>
844 &'a [OpTy<'tcx, Tag>; N]: TryFrom<&'a [OpTy<'tcx, Tag>]>,
846 if let Ok(ops) = args.try_into() {
849 throw_ub_format!("incorrect number of arguments: got {}, expected {}", args.len(), N)
852 pub fn isolation_abort_error<'tcx>(name: &str) -> InterpResult<'tcx> {
853 throw_machine_stop!(TerminationInfo::UnsupportedInIsolation(format!(
854 "{} not available when isolation is enabled",
859 /// Retrieve the list of local crates that should have been passed by cargo-miri in
860 /// MIRI_LOCAL_CRATES and turn them into `CrateNum`s.
861 pub fn get_local_crates(tcx: TyCtxt<'_>) -> Vec<CrateNum> {
862 // Convert the local crate names from the passed-in config into CrateNums so that they can
863 // be looked up quickly during execution
864 let local_crate_names = std::env::var("MIRI_LOCAL_CRATES")
865 .map(|crates| crates.split(',').map(|krate| krate.to_string()).collect::<Vec<_>>())
866 .unwrap_or_default();
867 let mut local_crates = Vec::new();
868 for &crate_num in tcx.crates(()) {
869 let name = tcx.crate_name(crate_num);
870 let name = name.as_str();
871 if local_crate_names.iter().any(|local_name| local_name == name) {
872 local_crates.push(crate_num);
878 /// Formats an AllocRange like [0x1..0x3], for use in diagnostics.
879 pub struct HexRange(pub AllocRange);
881 impl std::fmt::Display for HexRange {
882 fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
883 write!(f, "[{:#x}..{:#x}]", self.0.start.bytes(), self.0.end().bytes())