1 //! Global machine state as well as implementation of the interpreter engine
5 use std::cell::RefCell;
6 use std::num::NonZeroU64;
8 use std::time::Instant;
10 use rand::rngs::StdRng;
12 use rustc_data_structures::fx::FxHashMap;
16 layout::{LayoutOf, Size},
20 use rustc_span::{source_map::Span, symbol::{sym, Symbol}};
24 // Some global facts about the emulated machine.
25 pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
26 pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
27 pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
28 pub const NUM_CPUS: u64 = 1;
30 /// Extra data stored with each stack frame
32 pub struct FrameData<'tcx> {
33 /// Extra data for Stacked Borrows.
34 pub call_id: stacked_borrows::CallId,
36 /// If this is Some(), then this is a special "catch unwind" frame (the frame of `try_fn`
37 /// called by `try`). When this frame is popped during unwinding a panic,
38 /// we stop unwinding, use the `CatchUnwindData` to handle catching.
39 pub catch_unwind: Option<CatchUnwindData<'tcx>>,
42 /// Extra memory kinds
43 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
44 pub enum MiriMemoryKind {
45 /// `__rust_alloc` memory.
49 /// Windows `HeapAlloc` memory.
51 /// Memory for args, errno, extern statics and other parts of the machine-managed environment.
52 /// This memory may leak.
54 /// Memory for env vars. Separate from `Machine` because we clean it up and leak-check it.
56 /// Globals copied from `tcx`.
57 /// This memory may leak.
61 impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
63 fn into(self) -> MemoryKind<MiriMemoryKind> {
64 MemoryKind::Machine(self)
68 /// Extra per-allocation data
69 #[derive(Debug, Clone)]
70 pub struct AllocExtra {
71 /// Stacked Borrows state is only added if it is enabled.
72 pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
75 /// Extra global memory data
76 #[derive(Clone, Debug)]
77 pub struct MemoryExtra {
78 pub stacked_borrows: Option<stacked_borrows::MemoryExtra>,
79 pub intptrcast: intptrcast::MemoryExtra,
81 /// Mapping extern static names to their canonical allocation.
82 extern_statics: FxHashMap<Symbol, AllocId>,
84 /// The random number generator used for resolving non-determinism.
85 /// Needs to be queried by ptr_to_int, hence needs interior mutability.
86 pub(crate) rng: RefCell<StdRng>,
88 /// An allocation ID to report when it is being allocated
89 /// (helps for debugging memory leaks).
90 tracked_alloc_id: Option<AllocId>,
94 pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId>, tracked_alloc_id: Option<AllocId>) -> Self {
95 let stacked_borrows = if stacked_borrows {
96 Some(Rc::new(RefCell::new(stacked_borrows::GlobalState::new(tracked_pointer_tag))))
102 intptrcast: Default::default(),
103 extern_statics: FxHashMap::default(),
104 rng: RefCell::new(rng),
109 /// Sets up the "extern statics" for this machine.
110 pub fn init_extern_statics<'tcx, 'mir>(
111 this: &mut MiriEvalContext<'mir, 'tcx>,
112 ) -> InterpResult<'tcx> {
113 match this.tcx.sess.target.target.target_os.as_str() {
115 // "__cxa_thread_atexit_impl"
116 // This should be all-zero, pointer-sized.
117 let layout = this.layout_of(this.tcx.types.usize)?;
118 let place = this.allocate(layout, MiriMemoryKind::Machine.into());
119 this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
123 .insert(Symbol::intern("__cxa_thread_atexit_impl"), place.ptr.assert_ptr().alloc_id)
129 .insert(Symbol::intern("environ"), this.machine.env_vars.environ.unwrap().ptr.assert_ptr().alloc_id)
132 _ => {} // No "extern statics" supported on this target
138 /// The machine itself.
139 pub struct Evaluator<'tcx> {
140 /// Environment variables set by `setenv`.
141 /// Miri does not expose env vars from the host to the emulated program.
142 pub(crate) env_vars: EnvVars<'tcx>,
144 /// Program arguments (`Option` because we can only initialize them after creating the ecx).
145 /// These are *pointers* to argc/argv because macOS.
146 /// We also need the full command line as one string because of Windows.
147 pub(crate) argc: Option<Scalar<Tag>>,
148 pub(crate) argv: Option<Scalar<Tag>>,
149 pub(crate) cmd_line: Option<Scalar<Tag>>,
151 /// Last OS error location in memory. It is a 32-bit integer.
152 pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
155 pub(crate) tls: TlsData<'tcx>,
157 /// If enabled, the `env_vars` field is populated with the host env vars during initialization
158 /// and random number generation is delegated to the host.
159 pub(crate) communicate: bool,
161 /// Whether to enforce the validity invariant.
162 pub(crate) validate: bool,
164 pub(crate) file_handler: FileHandler,
165 pub(crate) dir_handler: DirHandler,
167 /// The temporary used for storing the argument of
168 /// the call to `miri_start_panic` (the panic payload) when unwinding.
169 /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
170 pub(crate) panic_payload: Option<Scalar<Tag>>,
172 /// The "time anchor" for this machine's monotone clock (for `Instant` simulation).
173 pub(crate) time_anchor: Instant,
176 impl<'tcx> Evaluator<'tcx> {
177 pub(crate) fn new(communicate: bool, validate: bool) -> Self {
179 // `env_vars` could be initialized properly here if `Memory` were available before
180 // calling this method.
181 env_vars: EnvVars::default(),
186 tls: TlsData::default(),
189 file_handler: Default::default(),
190 dir_handler: Default::default(),
192 time_anchor: Instant::now(),
197 /// A rustc InterpCx for Miri.
198 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
200 /// A little trait that's useful to be inherited by extension traits.
201 pub trait MiriEvalContextExt<'mir, 'tcx> {
202 fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
203 fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
205 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
207 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
211 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
216 /// Machine hook implementations.
217 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
218 type MemoryKind = MiriMemoryKind;
220 type FrameExtra = FrameData<'tcx>;
221 type MemoryExtra = MemoryExtra;
222 type AllocExtra = AllocExtra;
223 type PointerTag = Tag;
224 type ExtraFnVal = Dlsym;
227 MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
229 const GLOBAL_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Global);
231 const CHECK_ALIGN: bool = true;
234 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
239 fn find_mir_or_eval_fn(
240 ecx: &mut InterpCx<'mir, 'tcx, Self>,
242 instance: ty::Instance<'tcx>,
243 args: &[OpTy<'tcx, Tag>],
244 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
245 unwind: Option<mir::BasicBlock>,
246 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
247 ecx.find_mir_or_eval_fn(instance, args, ret, unwind)
252 ecx: &mut InterpCx<'mir, 'tcx, Self>,
254 args: &[OpTy<'tcx, Tag>],
255 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
256 _unwind: Option<mir::BasicBlock>,
257 ) -> InterpResult<'tcx> {
258 ecx.call_dlsym(fn_val, args, ret)
263 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
265 instance: ty::Instance<'tcx>,
266 args: &[OpTy<'tcx, Tag>],
267 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
268 unwind: Option<mir::BasicBlock>,
269 ) -> InterpResult<'tcx> {
270 ecx.call_intrinsic(span, instance, args, ret, unwind)
275 ecx: &mut InterpCx<'mir, 'tcx, Self>,
276 msg: &mir::AssertMessage<'tcx>,
277 unwind: Option<mir::BasicBlock>,
278 ) -> InterpResult<'tcx> {
279 ecx.assert_panic(msg, unwind)
283 fn abort(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, !> {
284 throw_machine_stop!(TerminationInfo::Abort(None))
289 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
291 left: ImmTy<'tcx, Tag>,
292 right: ImmTy<'tcx, Tag>,
293 ) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
294 ecx.binary_ptr_op(bin_op, left, right)
298 ecx: &mut InterpCx<'mir, 'tcx, Self>,
299 dest: PlaceTy<'tcx, Tag>,
300 ) -> InterpResult<'tcx> {
301 trace!("box_alloc for {:?}", dest.layout.ty);
302 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
303 // First argument: `size`.
304 // (`0` is allowed here -- this is expected to be handled by the lang item).
305 let size = Scalar::from_uint(layout.size.bytes(), ecx.pointer_size());
307 // Second argument: `align`.
308 let align = Scalar::from_uint(layout.align.abi.bytes(), ecx.pointer_size());
310 // Call the `exchange_malloc` lang item.
311 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
312 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
315 &[size.into(), align.into()],
317 // Don't do anything when we are done. The `statement()` function will increment
318 // the old stack frame's stmt counter to the next statement, which means that when
319 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
320 StackPopCleanup::None { cleanup: true },
325 fn canonical_alloc_id(mem: &Memory<'mir, 'tcx, Self>, id: AllocId) -> AllocId {
327 // Figure out if this is an extern static, and if yes, which one.
328 let def_id = match tcx.alloc_map.lock().get(id) {
329 Some(GlobalAlloc::Static(def_id)) if tcx.is_foreign_item(def_id) => def_id,
331 // No need to canonicalize anything.
335 let attrs = tcx.get_attrs(def_id);
336 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
338 None => tcx.item_name(def_id),
340 // Check if we know this one.
341 if let Some(canonical_id) = mem.extra.extern_statics.get(&link_name) {
342 trace!("canonical_alloc_id: {:?} ({}) -> {:?}", id, link_name, canonical_id);
345 // Return original id; `Memory::get_static_alloc` will throw an error.
350 fn init_allocation_extra<'b>(
351 memory_extra: &MemoryExtra,
353 alloc: Cow<'b, Allocation>,
354 kind: Option<MemoryKind<Self::MemoryKind>>,
355 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
356 if Some(id) == memory_extra.tracked_alloc_id {
357 register_diagnostic(NonHaltingDiagnostic::CreatedAlloc(id));
360 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
361 let alloc = alloc.into_owned();
362 let (stacks, base_tag) =
363 if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
364 let (stacks, base_tag) =
365 Stacks::new_allocation(id, alloc.size, Rc::clone(stacked_borrows), kind);
366 (Some(stacks), base_tag)
368 // No stacks, no tag.
369 (None, Tag::Untagged)
371 let mut stacked_borrows = memory_extra.stacked_borrows.as_ref().map(|sb| sb.borrow_mut());
372 let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
374 if let Some(stacked_borrows) = stacked_borrows.as_mut() {
375 // Only globals may already contain pointers at this point
376 assert_eq!(kind, MiriMemoryKind::Global.into());
377 stacked_borrows.global_base_ptr(alloc)
382 AllocExtra { stacked_borrows: stacks },
384 (Cow::Owned(alloc), base_tag)
388 fn tag_global_base_pointer(memory_extra: &MemoryExtra, id: AllocId) -> Self::PointerTag {
389 if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
390 stacked_borrows.borrow_mut().global_base_ptr(id)
398 ecx: &mut InterpCx<'mir, 'tcx, Self>,
399 kind: mir::RetagKind,
400 place: PlaceTy<'tcx, Tag>,
401 ) -> InterpResult<'tcx> {
402 if ecx.memory.extra.stacked_borrows.is_none() {
406 ecx.retag(kind, place)
411 fn stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, FrameData<'tcx>> {
412 let stacked_borrows = ecx.memory.extra.stacked_borrows.as_ref();
413 let call_id = stacked_borrows.map_or(NonZeroU64::new(1).unwrap(), |stacked_borrows| {
414 stacked_borrows.borrow_mut().new_call()
416 Ok(FrameData { call_id, catch_unwind: None })
421 ecx: &mut InterpCx<'mir, 'tcx, Self>,
422 extra: FrameData<'tcx>,
424 ) -> InterpResult<'tcx, StackPopJump> {
425 ecx.handle_stack_pop(extra, unwinding)
430 memory: &Memory<'mir, 'tcx, Self>,
432 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
433 intptrcast::GlobalState::int_to_ptr(int, memory)
438 memory: &Memory<'mir, 'tcx, Self>,
439 ptr: Pointer<Self::PointerTag>,
440 ) -> InterpResult<'tcx, u64> {
441 intptrcast::GlobalState::ptr_to_int(ptr, memory)
445 impl AllocationExtra<Tag> for AllocExtra {
447 fn memory_read<'tcx>(
448 alloc: &Allocation<Tag, AllocExtra>,
451 ) -> InterpResult<'tcx> {
452 if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
453 stacked_borrows.memory_read(ptr, size)
460 fn memory_written<'tcx>(
461 alloc: &mut Allocation<Tag, AllocExtra>,
464 ) -> InterpResult<'tcx> {
465 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
466 stacked_borrows.memory_written(ptr, size)
473 fn memory_deallocated<'tcx>(
474 alloc: &mut Allocation<Tag, AllocExtra>,
477 ) -> InterpResult<'tcx> {
478 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
479 stacked_borrows.memory_deallocated(ptr, size)
486 impl MayLeak for MiriMemoryKind {
488 fn may_leak(self) -> bool {
489 use self::MiriMemoryKind::*;
491 Rust | C | WinHeap | Env => false,
492 Machine | Global => true,