pub mod convert; use std::mem; use std::num::NonZeroUsize; use std::time::Duration; use log::trace; use rustc_hir::def_id::{DefId, CRATE_DEF_INDEX}; use rustc_middle::mir; use rustc_middle::ty::{ self, layout::{LayoutOf, TyAndLayout}, List, TyCtxt, }; use rustc_span::{def_id::CrateNum, sym, Span, Symbol}; use rustc_target::abi::{Align, FieldsShape, Size, Variants}; use rustc_target::spec::abi::Abi; use rand::RngCore; use crate::*; impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {} const UNIX_IO_ERROR_TABLE: &[(std::io::ErrorKind, &str)] = { use std::io::ErrorKind::*; &[ (ConnectionRefused, "ECONNREFUSED"), (ConnectionReset, "ECONNRESET"), (PermissionDenied, "EPERM"), (BrokenPipe, "EPIPE"), (NotConnected, "ENOTCONN"), (ConnectionAborted, "ECONNABORTED"), (AddrNotAvailable, "EADDRNOTAVAIL"), (AddrInUse, "EADDRINUSE"), (NotFound, "ENOENT"), (Interrupted, "EINTR"), (InvalidInput, "EINVAL"), (TimedOut, "ETIMEDOUT"), (AlreadyExists, "EEXIST"), (WouldBlock, "EWOULDBLOCK"), (DirectoryNotEmpty, "ENOTEMPTY"), ] }; /// Gets an instance for a path. fn try_resolve_did<'tcx>(tcx: TyCtxt<'tcx>, path: &[&str]) -> Option { tcx.crates(()).iter().find(|&&krate| tcx.crate_name(krate).as_str() == path[0]).and_then( |krate| { let krate = DefId { krate: *krate, index: CRATE_DEF_INDEX }; let mut items = tcx.module_children(krate); let mut path_it = path.iter().skip(1).peekable(); while let Some(segment) = path_it.next() { for item in mem::take(&mut items).iter() { if item.ident.name.as_str() == *segment { if path_it.peek().is_none() { return Some(item.res.def_id()); } items = tcx.module_children(item.res.def_id()); break; } } } None }, ) } pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> { /// Gets an instance for a path; fails gracefully if the path does not exist. fn try_resolve_path(&self, path: &[&str]) -> Option> { let did = try_resolve_did(self.eval_context_ref().tcx.tcx, path)?; Some(ty::Instance::mono(self.eval_context_ref().tcx.tcx, did)) } /// Gets an instance for a path. fn resolve_path(&self, path: &[&str]) -> ty::Instance<'tcx> { self.try_resolve_path(path) .unwrap_or_else(|| panic!("failed to find required Rust item: {:?}", path)) } /// Evaluates the scalar at the specified path. Returns Some(val) /// if the path could be resolved, and None otherwise fn eval_path_scalar(&self, path: &[&str]) -> InterpResult<'tcx, Scalar> { let this = self.eval_context_ref(); let instance = this.resolve_path(path); let cid = GlobalId { instance, promoted: None }; let const_val = this.eval_to_allocation(cid)?; let const_val = this.read_scalar(&const_val.into())?; const_val.check_init() } /// Helper function to get a `libc` constant as a `Scalar`. fn eval_libc(&self, name: &str) -> InterpResult<'tcx, Scalar> { self.eval_path_scalar(&["libc", name]) } /// Helper function to get a `libc` constant as an `i32`. fn eval_libc_i32(&self, name: &str) -> InterpResult<'tcx, i32> { // TODO: Cache the result. self.eval_libc(name)?.to_i32() } /// Helper function to get a `windows` constant as a `Scalar`. fn eval_windows(&self, module: &str, name: &str) -> InterpResult<'tcx, Scalar> { self.eval_context_ref().eval_path_scalar(&["std", "sys", "windows", module, name]) } /// Helper function to get a `windows` constant as a `u64`. fn eval_windows_u64(&self, module: &str, name: &str) -> InterpResult<'tcx, u64> { // TODO: Cache the result. self.eval_windows(module, name)?.to_u64() } /// Helper function to get the `TyAndLayout` of a `libc` type fn libc_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> { let this = self.eval_context_ref(); let ty = this.resolve_path(&["libc", name]).ty(*this.tcx, ty::ParamEnv::reveal_all()); this.layout_of(ty) } /// Helper function to get the `TyAndLayout` of a `windows` type fn windows_ty_layout(&self, name: &str) -> InterpResult<'tcx, TyAndLayout<'tcx>> { let this = self.eval_context_ref(); let ty = this .resolve_path(&["std", "sys", "windows", "c", name]) .ty(*this.tcx, ty::ParamEnv::reveal_all()); this.layout_of(ty) } /// Project to the given *named* field of the mplace (which must be a struct or union type). fn mplace_field_named( &self, mplace: &MPlaceTy<'tcx, Tag>, name: &str, ) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> { let this = self.eval_context_ref(); let adt = mplace.layout.ty.ty_adt_def().unwrap(); for (idx, field) in adt.non_enum_variant().fields.iter().enumerate() { if field.name.as_str() == name { return this.mplace_field(mplace, idx); } } bug!("No field named {} in type {}", name, mplace.layout.ty); } /// Write an int of the appropriate size to `dest`. The target type may be signed or unsigned, /// we try to do the right thing anyway. `i128` can fit all integer types except for `u128` so /// this method is fine for almost all integer types. fn write_int(&mut self, i: impl Into, dest: &PlaceTy<'tcx, Tag>) -> InterpResult<'tcx> { assert!(dest.layout.abi.is_scalar(), "write_int on non-scalar type {}", dest.layout.ty); let val = if dest.layout.abi.is_signed() { Scalar::from_int(i, dest.layout.size) } else { Scalar::from_uint(u64::try_from(i.into()).unwrap(), dest.layout.size) }; self.eval_context_mut().write_scalar(val, dest) } /// Write the first N fields of the given place. fn write_int_fields( &mut self, values: &[i128], dest: &MPlaceTy<'tcx, Tag>, ) -> InterpResult<'tcx> { let this = self.eval_context_mut(); for (idx, &val) in values.iter().enumerate() { let field = this.mplace_field(dest, idx)?; this.write_int(val, &field.into())?; } Ok(()) } /// Write the given fields of the given place. fn write_int_fields_named( &mut self, values: &[(&str, i128)], dest: &MPlaceTy<'tcx, Tag>, ) -> InterpResult<'tcx> { let this = self.eval_context_mut(); for &(name, val) in values.iter() { let field = this.mplace_field_named(dest, name)?; this.write_int(val, &field.into())?; } Ok(()) } /// Write a 0 of the appropriate size to `dest`. fn write_null(&mut self, dest: &PlaceTy<'tcx, Tag>) -> InterpResult<'tcx> { self.write_int(0, dest) } /// Test if this pointer equals 0. fn ptr_is_null(&self, ptr: Pointer>) -> InterpResult<'tcx, bool> { let this = self.eval_context_ref(); let null = Scalar::null_ptr(this); this.ptr_eq(Scalar::from_maybe_pointer(ptr, this), null) } /// Get the `Place` for a local fn local_place(&mut self, local: mir::Local) -> InterpResult<'tcx, PlaceTy<'tcx, Tag>> { let this = self.eval_context_mut(); let place = mir::Place { local, projection: List::empty() }; this.eval_place(place) } /// Generate some random bytes, and write them to `dest`. fn gen_random(&mut self, ptr: Pointer>, len: u64) -> InterpResult<'tcx> { // Some programs pass in a null pointer and a length of 0 // to their platform's random-generation function (e.g. getrandom()) // on Linux. For compatibility with these programs, we don't perform // any additional checks - it's okay if the pointer is invalid, // since we wouldn't actually be writing to it. if len == 0 { return Ok(()); } let this = self.eval_context_mut(); let mut data = vec![0; usize::try_from(len).unwrap()]; if this.machine.communicate() { // Fill the buffer using the host's rng. getrandom::getrandom(&mut data) .map_err(|err| err_unsup_format!("host getrandom failed: {}", err))?; } else { let rng = this.machine.rng.get_mut(); rng.fill_bytes(&mut data); } this.write_bytes_ptr(ptr, data.iter().copied()) } /// Call a function: Push the stack frame and pass the arguments. /// For now, arguments must be scalars (so that the caller does not have to know the layout). fn call_function( &mut self, f: ty::Instance<'tcx>, caller_abi: Abi, args: &[Immediate], dest: &PlaceTy<'tcx, Tag>, stack_pop: StackPopCleanup, ) -> InterpResult<'tcx> { let this = self.eval_context_mut(); let param_env = ty::ParamEnv::reveal_all(); // in Miri this is always the param_env we use... and this.param_env is private. let callee_abi = f.ty(*this.tcx, param_env).fn_sig(*this.tcx).abi(); if this.machine.enforce_abi && callee_abi != caller_abi { throw_ub_format!( "calling a function with ABI {} using caller ABI {}", callee_abi.name(), caller_abi.name() ) } // Push frame. let mir = this.load_mir(f.def, None)?; this.push_stack_frame(f, mir, dest, stack_pop)?; // Initialize arguments. let mut callee_args = this.frame().body.args_iter(); for arg in args { let callee_arg = this.local_place( callee_args .next() .ok_or_else(|| err_ub_format!("callee has fewer arguments than expected"))?, )?; this.write_immediate(*arg, &callee_arg)?; } if callee_args.next().is_some() { throw_ub_format!("callee has more arguments than expected"); } Ok(()) } /// Visits the memory covered by `place`, sensitive to freezing: the 2nd parameter /// of `action` will be true if this is frozen, false if this is in an `UnsafeCell`. /// The range is relative to `place`. fn visit_freeze_sensitive( &self, place: &MPlaceTy<'tcx, Tag>, size: Size, mut action: impl FnMut(AllocRange, bool) -> InterpResult<'tcx>, ) -> InterpResult<'tcx> { let this = self.eval_context_ref(); trace!("visit_frozen(place={:?}, size={:?})", *place, size); debug_assert_eq!( size, this.size_and_align_of_mplace(place)? .map(|(size, _)| size) .unwrap_or_else(|| place.layout.size) ); // Store how far we proceeded into the place so far. Everything to the left of // this offset has already been handled, in the sense that the frozen parts // have had `action` called on them. let start_addr = place.ptr.addr(); let mut cur_addr = start_addr; // Called when we detected an `UnsafeCell` at the given offset and size. // Calls `action` and advances `cur_ptr`. let mut unsafe_cell_action = |unsafe_cell_ptr: &Pointer>, unsafe_cell_size: Size| { // We assume that we are given the fields in increasing offset order, // and nothing else changes. let unsafe_cell_addr = unsafe_cell_ptr.addr(); assert!(unsafe_cell_addr >= cur_addr); let frozen_size = unsafe_cell_addr - cur_addr; // Everything between the cur_ptr and this `UnsafeCell` is frozen. if frozen_size != Size::ZERO { action(alloc_range(cur_addr - start_addr, frozen_size), /*frozen*/ true)?; } cur_addr += frozen_size; // This `UnsafeCell` is NOT frozen. if unsafe_cell_size != Size::ZERO { action( alloc_range(cur_addr - start_addr, unsafe_cell_size), /*frozen*/ false, )?; } cur_addr += unsafe_cell_size; // Done Ok(()) }; // Run a visitor { let mut visitor = UnsafeCellVisitor { ecx: this, unsafe_cell_action: |place| { trace!("unsafe_cell_action on {:?}", place.ptr); // We need a size to go on. let unsafe_cell_size = this .size_and_align_of_mplace(place)? .map(|(size, _)| size) // for extern types, just cover what we can .unwrap_or_else(|| place.layout.size); // Now handle this `UnsafeCell`, unless it is empty. if unsafe_cell_size != Size::ZERO { unsafe_cell_action(&place.ptr, unsafe_cell_size) } else { Ok(()) } }, }; visitor.visit_value(place)?; } // The part between the end_ptr and the end of the place is also frozen. // So pretend there is a 0-sized `UnsafeCell` at the end. unsafe_cell_action(&place.ptr.offset(size, this)?, Size::ZERO)?; // Done! return Ok(()); /// Visiting the memory covered by a `MemPlace`, being aware of /// whether we are inside an `UnsafeCell` or not. struct UnsafeCellVisitor<'ecx, 'mir, 'tcx, F> where F: FnMut(&MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>, { ecx: &'ecx MiriEvalContext<'mir, 'tcx>, unsafe_cell_action: F, } impl<'ecx, 'mir, 'tcx: 'mir, F> ValueVisitor<'mir, 'tcx, Evaluator<'mir, 'tcx>> for UnsafeCellVisitor<'ecx, 'mir, 'tcx, F> where F: FnMut(&MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx>, { type V = MPlaceTy<'tcx, Tag>; #[inline(always)] fn ecx(&self) -> &MiriEvalContext<'mir, 'tcx> { self.ecx } // Hook to detect `UnsafeCell`. fn visit_value(&mut self, v: &MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx> { trace!("UnsafeCellVisitor: {:?} {:?}", *v, v.layout.ty); let is_unsafe_cell = match v.layout.ty.kind() { ty::Adt(adt, _) => Some(adt.did()) == self.ecx.tcx.lang_items().unsafe_cell_type(), _ => false, }; if is_unsafe_cell { // We do not have to recurse further, this is an `UnsafeCell`. (self.unsafe_cell_action)(v) } else if self.ecx.type_is_freeze(v.layout.ty) { // This is `Freeze`, there cannot be an `UnsafeCell` Ok(()) } else if matches!(v.layout.fields, FieldsShape::Union(..)) { // A (non-frozen) union. We fall back to whatever the type says. (self.unsafe_cell_action)(v) } else { // We want to not actually read from memory for this visit. So, before // walking this value, we have to make sure it is not a // `Variants::Multiple`. match v.layout.variants { Variants::Multiple { .. } => { // A multi-variant enum, or generator, or so. // Treat this like a union: without reading from memory, // we cannot determine the variant we are in. Reading from // memory would be subject to Stacked Borrows rules, leading // to all sorts of "funny" recursion. // We only end up here if the type is *not* freeze, so we just call the // `UnsafeCell` action. (self.unsafe_cell_action)(v) } Variants::Single { .. } => { // Proceed further, try to find where exactly that `UnsafeCell` // is hiding. self.walk_value(v) } } } } // Make sure we visit aggregrates in increasing offset order. fn visit_aggregate( &mut self, place: &MPlaceTy<'tcx, Tag>, fields: impl Iterator>>, ) -> InterpResult<'tcx> { match place.layout.fields { FieldsShape::Array { .. } => { // For the array layout, we know the iterator will yield sorted elements so // we can avoid the allocation. self.walk_aggregate(place, fields) } FieldsShape::Arbitrary { .. } => { // Gather the subplaces and sort them before visiting. let mut places = fields.collect::>>>()?; // we just compare offsets, the abs. value never matters places.sort_by_key(|place| place.ptr.addr()); self.walk_aggregate(place, places.into_iter().map(Ok)) } FieldsShape::Union { .. } | FieldsShape::Primitive => { // Uh, what? bug!("unions/primitives are not aggregates we should ever visit") } } } fn visit_union( &mut self, _v: &MPlaceTy<'tcx, Tag>, _fields: NonZeroUsize, ) -> InterpResult<'tcx> { bug!("we should have already handled unions in `visit_value`") } } } /// Helper function used inside the shims of foreign functions to check that isolation is /// disabled. It returns an error using the `name` of the foreign function if this is not the /// case. fn check_no_isolation(&self, name: &str) -> InterpResult<'tcx> { if !self.eval_context_ref().machine.communicate() { self.reject_in_isolation(name, RejectOpWith::Abort)?; } Ok(()) } /// Helper function used inside the shims of foreign functions which reject the op /// when isolation is enabled. It is used to print a warning/backtrace about the rejection. fn reject_in_isolation(&self, op_name: &str, reject_with: RejectOpWith) -> InterpResult<'tcx> { let this = self.eval_context_ref(); match reject_with { RejectOpWith::Abort => isolation_abort_error(op_name), RejectOpWith::WarningWithoutBacktrace => { this.tcx .sess .warn(&format!("{} was made to return an error due to isolation", op_name)); Ok(()) } RejectOpWith::Warning => { register_diagnostic(NonHaltingDiagnostic::RejectedIsolatedOp(op_name.to_string())); Ok(()) } RejectOpWith::NoWarning => Ok(()), // no warning } } /// Helper function used inside the shims of foreign functions to assert that the target OS /// is `target_os`. It panics showing a message with the `name` of the foreign function /// if this is not the case. fn assert_target_os(&self, target_os: &str, name: &str) { assert_eq!( self.eval_context_ref().tcx.sess.target.os, target_os, "`{}` is only available on the `{}` target OS", name, target_os, ) } /// Get last error variable as a place, lazily allocating thread-local storage for it if /// necessary. fn last_error_place(&mut self) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> { let this = self.eval_context_mut(); if let Some(errno_place) = this.active_thread_ref().last_error { Ok(errno_place) } else { // Allocate new place, set initial value to 0. let errno_layout = this.machine.layouts.u32; let errno_place = this.allocate(errno_layout, MiriMemoryKind::Machine.into())?; this.write_scalar(Scalar::from_u32(0), &errno_place.into())?; this.active_thread_mut().last_error = Some(errno_place); Ok(errno_place) } } /// Sets the last error variable. fn set_last_error(&mut self, scalar: Scalar) -> InterpResult<'tcx> { let this = self.eval_context_mut(); let errno_place = this.last_error_place()?; this.write_scalar(scalar, &errno_place.into()) } /// Gets the last error variable. fn get_last_error(&mut self) -> InterpResult<'tcx, Scalar> { let this = self.eval_context_mut(); let errno_place = this.last_error_place()?; this.read_scalar(&errno_place.into())?.check_init() } /// This function tries to produce the most similar OS error from the `std::io::ErrorKind` /// as a platform-specific errnum. fn io_error_to_errnum(&self, err_kind: std::io::ErrorKind) -> InterpResult<'tcx, Scalar> { let this = self.eval_context_ref(); let target = &this.tcx.sess.target; if target.families.iter().any(|f| f == "unix") { for &(kind, name) in UNIX_IO_ERROR_TABLE { if err_kind == kind { return this.eval_libc(name); } } throw_unsup_format!("io error {:?} cannot be translated into a raw os error", err_kind) } else if target.families.iter().any(|f| f == "windows") { // FIXME: we have to finish implementing the Windows equivalent of this. use std::io::ErrorKind::*; this.eval_windows( "c", match err_kind { NotFound => "ERROR_FILE_NOT_FOUND", PermissionDenied => "ERROR_ACCESS_DENIED", _ => throw_unsup_format!( "io error {:?} cannot be translated into a raw os error", err_kind ), }, ) } else { throw_unsup_format!( "converting io::Error into errnum is unsupported for OS {}", target.os ) } } /// The inverse of `io_error_to_errnum`. fn errnum_to_io_error(&self, errnum: Scalar) -> InterpResult<'tcx, std::io::ErrorKind> { let this = self.eval_context_ref(); let target = &this.tcx.sess.target; if target.families.iter().any(|f| f == "unix") { let errnum = errnum.to_i32()?; for &(kind, name) in UNIX_IO_ERROR_TABLE { if errnum == this.eval_libc_i32(name)? { return Ok(kind); } } throw_unsup_format!("raw errnum {:?} cannot be translated into io::Error", errnum) } else { throw_unsup_format!( "converting errnum into io::Error is unsupported for OS {}", target.os ) } } /// Sets the last OS error using a `std::io::ErrorKind`. fn set_last_error_from_io_error(&mut self, err_kind: std::io::ErrorKind) -> InterpResult<'tcx> { self.set_last_error(self.io_error_to_errnum(err_kind)?) } /// Helper function that consumes an `std::io::Result` and returns an /// `InterpResult<'tcx,T>::Ok` instead. In case the result is an error, this function returns /// `Ok(-1)` and sets the last OS error accordingly. /// /// This function uses `T: From` instead of `i32` directly because some IO related /// functions return different integer types (like `read`, that returns an `i64`). fn try_unwrap_io_result>( &mut self, result: std::io::Result, ) -> InterpResult<'tcx, T> { match result { Ok(ok) => Ok(ok), Err(e) => { self.eval_context_mut().set_last_error_from_io_error(e.kind())?; Ok((-1).into()) } } } /// Calculates the MPlaceTy given the offset and layout of an access on an operand fn deref_operand_and_offset( &self, op: &OpTy<'tcx, Tag>, offset: u64, layout: TyAndLayout<'tcx>, ) -> InterpResult<'tcx, MPlaceTy<'tcx, Tag>> { let this = self.eval_context_ref(); let op_place = this.deref_operand(op)?; let offset = Size::from_bytes(offset); // Ensure that the access is within bounds. assert!(op_place.layout.size >= offset + layout.size); let value_place = op_place.offset(offset, MemPlaceMeta::None, layout, this)?; Ok(value_place) } fn read_scalar_at_offset( &self, op: &OpTy<'tcx, Tag>, offset: u64, layout: TyAndLayout<'tcx>, ) -> InterpResult<'tcx, ScalarMaybeUninit> { let this = self.eval_context_ref(); let value_place = this.deref_operand_and_offset(op, offset, layout)?; this.read_scalar(&value_place.into()) } fn write_scalar_at_offset( &mut self, op: &OpTy<'tcx, Tag>, offset: u64, value: impl Into>, layout: TyAndLayout<'tcx>, ) -> InterpResult<'tcx, ()> { let this = self.eval_context_mut(); let value_place = this.deref_operand_and_offset(op, offset, layout)?; this.write_scalar(value, &value_place.into()) } /// Parse a `timespec` struct and return it as a `std::time::Duration`. It returns `None` /// if the value in the `timespec` struct is invalid. Some libc functions will return /// `EINVAL` in this case. fn read_timespec(&mut self, tp: &MPlaceTy<'tcx, Tag>) -> InterpResult<'tcx, Option> { let this = self.eval_context_mut(); let seconds_place = this.mplace_field(tp, 0)?; let seconds_scalar = this.read_scalar(&seconds_place.into())?; let seconds = seconds_scalar.to_machine_isize(this)?; let nanoseconds_place = this.mplace_field(tp, 1)?; let nanoseconds_scalar = this.read_scalar(&nanoseconds_place.into())?; let nanoseconds = nanoseconds_scalar.to_machine_isize(this)?; Ok(try { // tv_sec must be non-negative. let seconds: u64 = seconds.try_into().ok()?; // tv_nsec must be non-negative. let nanoseconds: u32 = nanoseconds.try_into().ok()?; if nanoseconds >= 1_000_000_000 { // tv_nsec must not be greater than 999,999,999. None? } Duration::new(seconds, nanoseconds) }) } fn read_c_str<'a>(&'a self, ptr: Pointer>) -> InterpResult<'tcx, &'a [u8]> where 'tcx: 'a, 'mir: 'a, { let this = self.eval_context_ref(); let size1 = Size::from_bytes(1); // Step 1: determine the length. let mut len = Size::ZERO; loop { // FIXME: We are re-getting the allocation each time around the loop. // Would be nice if we could somehow "extend" an existing AllocRange. let alloc = this.get_ptr_alloc(ptr.offset(len, this)?, size1, Align::ONE)?.unwrap(); // not a ZST, so we will get a result let byte = alloc.read_integer(Size::ZERO, size1)?.to_u8()?; if byte == 0 { break; } else { len += size1; } } // Step 2: get the bytes. this.read_bytes_ptr(ptr, len) } fn read_wide_str(&self, mut ptr: Pointer>) -> InterpResult<'tcx, Vec> { let this = self.eval_context_ref(); let size2 = Size::from_bytes(2); let align2 = Align::from_bytes(2).unwrap(); let mut wchars = Vec::new(); loop { // FIXME: We are re-getting the allocation each time around the loop. // Would be nice if we could somehow "extend" an existing AllocRange. let alloc = this.get_ptr_alloc(ptr, size2, align2)?.unwrap(); // not a ZST, so we will get a result let wchar = alloc.read_integer(Size::ZERO, size2)?.to_u16()?; if wchar == 0 { break; } else { wchars.push(wchar); ptr = ptr.offset(size2, this)?; } } Ok(wchars) } /// Check that the ABI is what we expect. fn check_abi<'a>(&self, abi: Abi, exp_abi: Abi) -> InterpResult<'a, ()> { if self.eval_context_ref().machine.enforce_abi && abi != exp_abi { throw_ub_format!( "calling a function with ABI {} using caller ABI {}", exp_abi.name(), abi.name() ) } Ok(()) } fn frame_in_std(&self) -> bool { let this = self.eval_context_ref(); let Some(start_fn) = this.tcx.lang_items().start_fn() else { // no_std situations return false; }; let frame = this.frame(); // Make an attempt to get at the instance of the function this is inlined from. let instance: Option<_> = try { let scope = frame.current_source_info()?.scope; let inlined_parent = frame.body.source_scopes[scope].inlined_parent_scope?; let source = &frame.body.source_scopes[inlined_parent]; source.inlined.expect("inlined_parent_scope points to scope without inline info").0 }; // Fall back to the instance of the function itself. let instance = instance.unwrap_or(frame.instance); // Now check if this is in the same crate as start_fn. this.tcx.def_path(instance.def_id()).krate == this.tcx.def_path(start_fn).krate } /// Handler that should be called when unsupported functionality is encountered. /// This function will either panic within the context of the emulated application /// or return an error in the Miri process context /// /// Return value of `Ok(bool)` indicates whether execution should continue. fn handle_unsupported>(&mut self, error_msg: S) -> InterpResult<'tcx, ()> { let this = self.eval_context_mut(); if this.machine.panic_on_unsupported { // message is slightly different here to make automated analysis easier let error_msg = format!("unsupported Miri functionality: {}", error_msg.as_ref()); this.start_panic(error_msg.as_ref(), StackPopUnwind::Skip)?; Ok(()) } else { throw_unsup_format!("{}", error_msg.as_ref()); } } fn check_abi_and_shim_symbol_clash( &mut self, abi: Abi, exp_abi: Abi, link_name: Symbol, ) -> InterpResult<'tcx, ()> { self.check_abi(abi, exp_abi)?; if let Some((body, _)) = self.eval_context_mut().lookup_exported_symbol(link_name)? { throw_machine_stop!(TerminationInfo::SymbolShimClashing { link_name, span: body.span.data(), }) } Ok(()) } fn check_shim<'a, const N: usize>( &mut self, abi: Abi, exp_abi: Abi, link_name: Symbol, args: &'a [OpTy<'tcx, Tag>], ) -> InterpResult<'tcx, &'a [OpTy<'tcx, Tag>; N]> where &'a [OpTy<'tcx, Tag>; N]: TryFrom<&'a [OpTy<'tcx, Tag>]>, { self.check_abi_and_shim_symbol_clash(abi, exp_abi, link_name)?; check_arg_count(args) } /// Mark a machine allocation that was just created as immutable. fn mark_immutable(&mut self, mplace: &MemPlace) { let this = self.eval_context_mut(); // This got just allocated, so there definitely is a pointer here. let provenance = mplace.ptr.into_pointer_or_addr().unwrap().provenance; this.alloc_mark_immutable(provenance.get_alloc_id().unwrap()).unwrap(); } fn item_link_name(&self, def_id: DefId) -> Symbol { let tcx = self.eval_context_ref().tcx; match tcx.get_attrs(def_id, sym::link_name).filter_map(|a| a.value_str()).next() { Some(name) => name, None => tcx.item_name(def_id), } } } impl<'mir, 'tcx> Evaluator<'mir, 'tcx> { pub fn current_span(&self) -> CurrentSpan<'_, 'mir, 'tcx> { CurrentSpan { span: None, machine: self } } } /// A `CurrentSpan` should be created infrequently (ideally once) per interpreter step. It does /// nothing on creation, but when `CurrentSpan::get` is called, searches the current stack for the /// topmost frame which corresponds to a local crate, and returns the current span in that frame. /// The result of that search is cached so that later calls are approximately free. #[derive(Clone)] pub struct CurrentSpan<'a, 'mir, 'tcx> { span: Option, machine: &'a Evaluator<'mir, 'tcx>, } impl<'a, 'mir, 'tcx> CurrentSpan<'a, 'mir, 'tcx> { pub fn get(&mut self) -> Span { *self.span.get_or_insert_with(|| Self::current_span(self.machine)) } #[inline(never)] fn current_span(machine: &Evaluator<'_, '_>) -> Span { machine .threads .active_thread_stack() .iter() .rev() .find(|frame| { let def_id = frame.instance.def_id(); def_id.is_local() || machine.local_crates.contains(&def_id.krate) }) .map(|frame| frame.current_span()) .unwrap_or(rustc_span::DUMMY_SP) } } /// Check that the number of args is what we expect. pub fn check_arg_count<'a, 'tcx, const N: usize>( args: &'a [OpTy<'tcx, Tag>], ) -> InterpResult<'tcx, &'a [OpTy<'tcx, Tag>; N]> where &'a [OpTy<'tcx, Tag>; N]: TryFrom<&'a [OpTy<'tcx, Tag>]>, { if let Ok(ops) = args.try_into() { return Ok(ops); } throw_ub_format!("incorrect number of arguments: got {}, expected {}", args.len(), N) } pub fn isolation_abort_error<'tcx>(name: &str) -> InterpResult<'tcx> { throw_machine_stop!(TerminationInfo::UnsupportedInIsolation(format!( "{} not available when isolation is enabled", name, ))) } /// Retrieve the list of local crates that should have been passed by cargo-miri in /// MIRI_LOCAL_CRATES and turn them into `CrateNum`s. pub fn get_local_crates(tcx: TyCtxt<'_>) -> Vec { // Convert the local crate names from the passed-in config into CrateNums so that they can // be looked up quickly during execution let local_crate_names = std::env::var("MIRI_LOCAL_CRATES") .map(|crates| crates.split(',').map(|krate| krate.to_string()).collect::>()) .unwrap_or_default(); let mut local_crates = Vec::new(); for &crate_num in tcx.crates(()) { let name = tcx.crate_name(crate_num); let name = name.as_str(); if local_crate_names.iter().any(|local_name| local_name == name) { local_crates.push(crate_num); } } local_crates } /// Formats an AllocRange like [0x1..0x3], for use in diagnostics. pub struct HexRange(pub AllocRange); impl std::fmt::Display for HexRange { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "[{:#x}..{:#x}]", self.0.start.bytes(), self.0.end().bytes()) } } /// Helper function used inside the shims of foreign functions to check that /// `target_os` is a supported UNIX OS. pub fn target_os_is_unix(target_os: &str) -> bool { matches!(target_os, "linux" | "macos") }