1 //! Global machine state as well as implementation of the interpreter engine
5 use std::cell::RefCell;
8 use rand::rngs::StdRng;
10 use rustc_hir::def_id::DefId;
14 layout::{LayoutOf, Size},
17 use rustc_span::{source_map::Span, symbol::sym};
22 // Some global facts about the emulated machine.
23 pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
24 pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
25 pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
26 pub const NUM_CPUS: u64 = 1;
28 /// Extra data stored with each stack frame
30 pub struct FrameData<'tcx> {
31 /// Extra data for Stacked Borrows.
32 pub call_id: stacked_borrows::CallId,
34 /// If this is Some(), then this is a special "catch unwind" frame (the frame of the closure
35 /// called by `__rustc_maybe_catch_panic`). When this frame is popped during unwinding a panic,
36 /// we stop unwinding, use the `CatchUnwindData` to
37 /// store the panic payload, and continue execution in the parent frame.
38 pub catch_panic: Option<CatchUnwindData<'tcx>>,
41 /// Extra memory kinds
42 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
43 pub enum MiriMemoryKind {
44 /// `__rust_alloc` memory.
48 /// Windows `HeapAlloc` memory.
50 /// Memory for env vars and args, errno and other parts of the machine-managed environment.
56 impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
58 fn into(self) -> MemoryKind<MiriMemoryKind> {
59 MemoryKind::Machine(self)
63 /// Extra per-allocation data
64 #[derive(Debug, Clone)]
65 pub struct AllocExtra {
66 /// Stacked Borrows state is only added if validation is enabled.
67 pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
70 /// Extra global memory data
71 #[derive(Clone, Debug)]
72 pub struct MemoryExtra {
73 pub stacked_borrows: stacked_borrows::MemoryExtra,
74 pub intptrcast: intptrcast::MemoryExtra,
76 /// The random number generator used for resolving non-determinism.
77 pub(crate) rng: RefCell<StdRng>,
79 /// Whether to enforce the validity invariant.
80 pub(crate) validate: bool,
84 pub fn new(rng: StdRng, validate: bool, tracked_pointer_tag: Option<PtrId>) -> Self {
86 stacked_borrows: Rc::new(RefCell::new(GlobalState::new(tracked_pointer_tag))),
87 intptrcast: Default::default(),
88 rng: RefCell::new(rng),
94 /// The machine itself.
95 pub struct Evaluator<'tcx> {
96 /// Environment variables set by `setenv`.
97 /// Miri does not expose env vars from the host to the emulated program.
98 pub(crate) env_vars: EnvVars,
100 /// Program arguments (`Option` because we can only initialize them after creating the ecx).
101 /// These are *pointers* to argc/argv because macOS.
102 /// We also need the full command line as one string because of Windows.
103 pub(crate) argc: Option<Scalar<Tag>>,
104 pub(crate) argv: Option<Scalar<Tag>>,
105 pub(crate) cmd_line: Option<Scalar<Tag>>,
107 /// Last OS error location in memory. It is a 32-bit integer.
108 pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
111 pub(crate) tls: TlsData<'tcx>,
113 /// If enabled, the `env_vars` field is populated with the host env vars during initialization
114 /// and random number generation is delegated to the host.
115 pub(crate) communicate: bool,
117 pub(crate) file_handler: FileHandler,
119 /// The temporary used for storing the argument of
120 /// the call to `miri_start_panic` (the panic payload) when unwinding.
121 pub(crate) panic_payload: Option<ImmTy<'tcx, Tag>>,
124 impl<'tcx> Evaluator<'tcx> {
125 pub(crate) fn new(communicate: bool) -> Self {
127 // `env_vars` could be initialized properly here if `Memory` were available before
128 // calling this method.
129 env_vars: EnvVars::default(),
134 tls: TlsData::default(),
136 file_handler: Default::default(),
142 /// A rustc InterpCx for Miri.
143 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
145 /// A little trait that's useful to be inherited by extension traits.
146 pub trait MiriEvalContextExt<'mir, 'tcx> {
147 fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
148 fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
150 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
152 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
156 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
161 /// Machine hook implementations.
162 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
163 type MemoryKinds = MiriMemoryKind;
165 type FrameExtra = FrameData<'tcx>;
166 type MemoryExtra = MemoryExtra;
167 type AllocExtra = AllocExtra;
168 type PointerTag = Tag;
169 type ExtraFnVal = Dlsym;
172 MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
174 const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
176 const CHECK_ALIGN: bool = true;
179 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
180 ecx.memory.extra.validate
184 fn find_mir_or_eval_fn(
185 ecx: &mut InterpCx<'mir, 'tcx, Self>,
187 instance: ty::Instance<'tcx>,
188 args: &[OpTy<'tcx, Tag>],
189 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
190 unwind: Option<mir::BasicBlock>,
191 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
192 ecx.find_mir_or_eval_fn(instance, args, ret, unwind)
197 ecx: &mut InterpCx<'mir, 'tcx, Self>,
199 args: &[OpTy<'tcx, Tag>],
200 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
201 _unwind: Option<mir::BasicBlock>,
202 ) -> InterpResult<'tcx> {
203 ecx.call_dlsym(fn_val, args, ret)
208 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
210 instance: ty::Instance<'tcx>,
211 args: &[OpTy<'tcx, Tag>],
212 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
213 unwind: Option<mir::BasicBlock>,
214 ) -> InterpResult<'tcx> {
215 ecx.call_intrinsic(span, instance, args, ret, unwind)
220 ecx: &mut InterpCx<'mir, 'tcx, Self>,
222 msg: &mir::AssertMessage<'tcx>,
223 unwind: Option<mir::BasicBlock>,
224 ) -> InterpResult<'tcx> {
225 ecx.assert_panic(span, msg, unwind)
230 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
232 left: ImmTy<'tcx, Tag>,
233 right: ImmTy<'tcx, Tag>,
234 ) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
235 ecx.binary_ptr_op(bin_op, left, right)
239 ecx: &mut InterpCx<'mir, 'tcx, Self>,
240 dest: PlaceTy<'tcx, Tag>,
241 ) -> InterpResult<'tcx> {
242 trace!("box_alloc for {:?}", dest.layout.ty);
243 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
244 // First argument: `size`.
245 // (`0` is allowed here -- this is expected to be handled by the lang item).
246 let size = Scalar::from_uint(layout.size.bytes(), ecx.pointer_size());
248 // Second argument: `align`.
249 let align = Scalar::from_uint(layout.align.abi.bytes(), ecx.pointer_size());
251 // Call the `exchange_malloc` lang item.
252 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
253 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
256 &[size.into(), align.into()],
258 // Don't do anything when we are done. The `statement()` function will increment
259 // the old stack frame's stmt counter to the next statement, which means that when
260 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
261 StackPopCleanup::None { cleanup: true },
266 fn find_foreign_static(
269 ) -> InterpResult<'tcx, Cow<'tcx, Allocation>> {
270 let attrs = tcx.get_attrs(def_id);
271 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
272 Some(name) => name.as_str(),
273 None => tcx.item_name(def_id).as_str(),
276 let alloc = match &*link_name {
277 "__cxa_thread_atexit_impl" => {
278 // This should be all-zero, pointer-sized.
279 let size = tcx.data_layout.pointer_size;
280 let data = vec![0; size.bytes() as usize];
281 Allocation::from_bytes(&data, tcx.data_layout.pointer_align.abi)
283 _ => throw_unsup_format!("can't access foreign static: {}", link_name),
285 Ok(Cow::Owned(alloc))
289 fn before_terminator(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
290 // We are not interested in detecting loops.
294 fn init_allocation_extra<'b>(
295 memory_extra: &MemoryExtra,
297 alloc: Cow<'b, Allocation>,
298 kind: Option<MemoryKind<Self::MemoryKinds>>,
299 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
300 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
301 let alloc = alloc.into_owned();
302 let (stacks, base_tag) = if memory_extra.validate {
303 let (stacks, base_tag) = Stacks::new_allocation(
306 Rc::clone(&memory_extra.stacked_borrows),
309 (Some(stacks), base_tag)
311 // No stacks, no tag.
312 (None, Tag::Untagged)
314 let mut stacked_borrows = memory_extra.stacked_borrows.borrow_mut();
315 let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
317 if !memory_extra.validate {
320 // Only statics may already contain pointers at this point
321 assert_eq!(kind, MiriMemoryKind::Static.into());
322 stacked_borrows.static_base_ptr(alloc)
325 AllocExtra { stacked_borrows: stacks },
327 (Cow::Owned(alloc), base_tag)
331 fn tag_static_base_pointer(memory_extra: &MemoryExtra, id: AllocId) -> Self::PointerTag {
332 if !memory_extra.validate {
335 memory_extra.stacked_borrows.borrow_mut().static_base_ptr(id)
341 ecx: &mut InterpCx<'mir, 'tcx, Self>,
342 kind: mir::RetagKind,
343 place: PlaceTy<'tcx, Tag>,
344 ) -> InterpResult<'tcx> {
345 if !Self::enforce_validity(ecx) {
349 ecx.retag(kind, place)
354 fn stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, FrameData<'tcx>> {
356 call_id: ecx.memory.extra.stacked_borrows.borrow_mut().new_call(),
363 ecx: &mut InterpCx<'mir, 'tcx, Self>,
364 extra: FrameData<'tcx>,
366 ) -> InterpResult<'tcx, StackPopInfo> {
367 ecx.handle_stack_pop(extra, unwinding)
372 memory: &Memory<'mir, 'tcx, Self>,
374 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
375 intptrcast::GlobalState::int_to_ptr(int, memory)
380 memory: &Memory<'mir, 'tcx, Self>,
381 ptr: Pointer<Self::PointerTag>,
382 ) -> InterpResult<'tcx, u64> {
383 intptrcast::GlobalState::ptr_to_int(ptr, memory)
387 impl AllocationExtra<Tag> for AllocExtra {
389 fn memory_read<'tcx>(
390 alloc: &Allocation<Tag, AllocExtra>,
393 ) -> InterpResult<'tcx> {
394 if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
395 stacked_borrows.memory_read(ptr, size)
402 fn memory_written<'tcx>(
403 alloc: &mut Allocation<Tag, AllocExtra>,
406 ) -> InterpResult<'tcx> {
407 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
408 stacked_borrows.memory_written(ptr, size)
415 fn memory_deallocated<'tcx>(
416 alloc: &mut Allocation<Tag, AllocExtra>,
419 ) -> InterpResult<'tcx> {
420 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
421 stacked_borrows.memory_deallocated(ptr, size)
428 impl MayLeak for MiriMemoryKind {
430 fn may_leak(self) -> bool {
431 use self::MiriMemoryKind::*;
433 Rust | C | WinHeap => false,
434 Env | Static => true,