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;
12 use rand::rngs::StdRng;
15 use rustc_data_structures::fx::FxHashMap;
20 layout::{LayoutCx, LayoutError, TyAndLayout},
24 use rustc_span::symbol::{sym, Symbol};
25 use rustc_span::def_id::DefId;
26 use rustc_target::abi::{LayoutOf, Size};
30 // Some global facts about the emulated machine.
31 pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
32 pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
33 pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
34 pub const NUM_CPUS: u64 = 1;
36 /// Extra data stored with each stack frame
38 pub struct FrameData<'tcx> {
39 /// Extra data for Stacked Borrows.
40 pub call_id: stacked_borrows::CallId,
42 /// If this is Some(), then this is a special "catch unwind" frame (the frame of `try_fn`
43 /// called by `try`). When this frame is popped during unwinding a panic,
44 /// we stop unwinding, use the `CatchUnwindData` to handle catching.
45 pub catch_unwind: Option<CatchUnwindData<'tcx>>,
48 /// Extra memory kinds
49 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
50 pub enum MiriMemoryKind {
51 /// `__rust_alloc` memory.
55 /// Windows `HeapAlloc` memory.
57 /// Memory for args, errno, extern statics and other parts of the machine-managed environment.
58 /// This memory may leak.
60 /// Memory for env vars. Separate from `Machine` because we clean it up and leak-check it.
62 /// Globals copied from `tcx`.
63 /// This memory may leak.
67 impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
69 fn into(self) -> MemoryKind<MiriMemoryKind> {
70 MemoryKind::Machine(self)
74 impl MayLeak for MiriMemoryKind {
76 fn may_leak(self) -> bool {
77 use self::MiriMemoryKind::*;
79 Rust | C | WinHeap | Env => false,
80 Machine | Global => true,
85 impl fmt::Display for MiriMemoryKind {
86 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
87 use self::MiriMemoryKind::*;
89 Rust => write!(f, "Rust heap"),
90 C => write!(f, "C heap"),
91 WinHeap => write!(f, "Windows heap"),
92 Machine => write!(f, "machine-managed memory"),
93 Env => write!(f, "environment variable"),
94 Global => write!(f, "global"),
99 /// Extra per-allocation data
100 #[derive(Debug, Clone)]
101 pub struct AllocExtra {
102 /// Stacked Borrows state is only added if it is enabled.
103 pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
106 /// Extra global memory data
107 #[derive(Clone, Debug)]
108 pub struct MemoryExtra {
109 pub stacked_borrows: Option<stacked_borrows::MemoryExtra>,
110 pub intptrcast: intptrcast::MemoryExtra,
112 /// Mapping extern static names to their canonical allocation.
113 extern_statics: FxHashMap<Symbol, AllocId>,
115 /// The random number generator used for resolving non-determinism.
116 /// Needs to be queried by ptr_to_int, hence needs interior mutability.
117 pub(crate) rng: RefCell<StdRng>,
119 /// An allocation ID to report when it is being allocated
120 /// (helps for debugging memory leaks and use after free bugs).
121 tracked_alloc_id: Option<AllocId>,
123 /// Controls whether alignment of memory accesses is being checked.
124 check_alignment: bool,
130 stacked_borrows: bool,
131 tracked_pointer_tag: Option<PtrId>,
132 tracked_alloc_id: Option<AllocId>,
133 check_alignment: bool,
135 let stacked_borrows = if stacked_borrows {
136 Some(Rc::new(RefCell::new(stacked_borrows::GlobalState::new(tracked_pointer_tag))))
142 intptrcast: Default::default(),
143 extern_statics: FxHashMap::default(),
144 rng: RefCell::new(rng),
150 fn add_extern_static<'tcx, 'mir>(
151 this: &mut MiriEvalContext<'mir, 'tcx>,
155 let ptr = ptr.assert_ptr();
156 assert_eq!(ptr.offset, Size::ZERO);
160 .insert(Symbol::intern(name), ptr.alloc_id)
164 /// Sets up the "extern statics" for this machine.
165 pub fn init_extern_statics<'tcx, 'mir>(
166 this: &mut MiriEvalContext<'mir, 'tcx>,
167 ) -> InterpResult<'tcx> {
168 match this.tcx.sess.target.target.target_os.as_str() {
170 // "__cxa_thread_atexit_impl"
171 // This should be all-zero, pointer-sized.
172 let layout = this.machine.layouts.usize;
173 let place = this.allocate(layout, MiriMemoryKind::Machine.into());
174 this.write_scalar(Scalar::from_machine_usize(0, this), place.into())?;
175 Self::add_extern_static(this, "__cxa_thread_atexit_impl", place.ptr);
177 Self::add_extern_static(this, "environ", this.machine.env_vars.environ.unwrap().ptr);
181 // This is some obscure hack that is part of the Windows TLS story. It's a `u8`.
182 let layout = this.machine.layouts.u8;
183 let place = this.allocate(layout, MiriMemoryKind::Machine.into());
184 this.write_scalar(Scalar::from_u8(0), place.into())?;
185 Self::add_extern_static(this, "_tls_used", place.ptr);
187 _ => {} // No "extern statics" supported on this target
193 /// Precomputed layouts of primitive types
194 pub struct PrimitiveLayouts<'tcx> {
195 pub unit: TyAndLayout<'tcx>,
196 pub i8: TyAndLayout<'tcx>,
197 pub i32: TyAndLayout<'tcx>,
198 pub isize: TyAndLayout<'tcx>,
199 pub u8: TyAndLayout<'tcx>,
200 pub u32: TyAndLayout<'tcx>,
201 pub usize: TyAndLayout<'tcx>,
204 impl<'mir, 'tcx: 'mir> PrimitiveLayouts<'tcx> {
205 fn new(layout_cx: LayoutCx<'tcx, TyCtxt<'tcx>>) -> Result<Self, LayoutError<'tcx>> {
207 unit: layout_cx.layout_of(layout_cx.tcx.mk_unit())?,
208 i8: layout_cx.layout_of(layout_cx.tcx.types.i8)?,
209 i32: layout_cx.layout_of(layout_cx.tcx.types.i32)?,
210 isize: layout_cx.layout_of(layout_cx.tcx.types.isize)?,
211 u8: layout_cx.layout_of(layout_cx.tcx.types.u8)?,
212 u32: layout_cx.layout_of(layout_cx.tcx.types.u32)?,
213 usize: layout_cx.layout_of(layout_cx.tcx.types.usize)?,
218 /// The machine itself.
219 pub struct Evaluator<'mir, 'tcx> {
220 /// Environment variables set by `setenv`.
221 /// Miri does not expose env vars from the host to the emulated program.
222 pub(crate) env_vars: EnvVars<'tcx>,
224 /// Program arguments (`Option` because we can only initialize them after creating the ecx).
225 /// These are *pointers* to argc/argv because macOS.
226 /// We also need the full command line as one string because of Windows.
227 pub(crate) argc: Option<Scalar<Tag>>,
228 pub(crate) argv: Option<Scalar<Tag>>,
229 pub(crate) cmd_line: Option<Scalar<Tag>>,
231 /// Last OS error location in memory. It is a 32-bit integer.
232 pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
235 pub(crate) tls: TlsData<'tcx>,
237 /// If enabled, the `env_vars` field is populated with the host env vars during initialization
238 /// and random number generation is delegated to the host.
239 pub(crate) communicate: bool,
241 /// Whether to enforce the validity invariant.
242 pub(crate) validate: bool,
244 pub(crate) file_handler: FileHandler,
245 pub(crate) dir_handler: DirHandler,
247 /// The temporary used for storing the argument of
248 /// the call to `miri_start_panic` (the panic payload) when unwinding.
249 /// This is pointer-sized, and matches the `Payload` type in `src/libpanic_unwind/miri.rs`.
250 pub(crate) panic_payload: Option<Scalar<Tag>>,
252 /// The "time anchor" for this machine's monotone clock (for `Instant` simulation).
253 pub(crate) time_anchor: Instant,
255 /// The set of threads.
256 pub(crate) threads: ThreadManager<'mir, 'tcx>,
258 /// Precomputed `TyLayout`s for primitive data types that are commonly used inside Miri.
259 pub(crate) layouts: PrimitiveLayouts<'tcx>,
262 impl<'mir, 'tcx> Evaluator<'mir, 'tcx> {
266 layout_cx: LayoutCx<'tcx, TyCtxt<'tcx>>,
268 let layouts = PrimitiveLayouts::new(layout_cx)
269 .expect("Couldn't get layouts of primitive types");
271 // `env_vars` could be initialized properly here if `Memory` were available before
272 // calling this method.
273 env_vars: EnvVars::default(),
278 tls: TlsData::default(),
281 file_handler: Default::default(),
282 dir_handler: Default::default(),
284 time_anchor: Instant::now(),
286 threads: ThreadManager::default(),
291 /// A rustc InterpCx for Miri.
292 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'mir, 'tcx>>;
294 /// A little trait that's useful to be inherited by extension traits.
295 pub trait MiriEvalContextExt<'mir, 'tcx> {
296 fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
297 fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
299 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
301 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
305 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
310 /// Machine hook implementations.
311 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'mir, 'tcx> {
312 type MemoryKind = MiriMemoryKind;
314 type FrameExtra = FrameData<'tcx>;
315 type MemoryExtra = MemoryExtra;
316 type AllocExtra = AllocExtra;
317 type PointerTag = Tag;
318 type ExtraFnVal = Dlsym;
321 MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
323 const GLOBAL_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Global);
326 fn enforce_alignment(memory_extra: &MemoryExtra) -> bool {
327 memory_extra.check_alignment
331 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
336 fn find_mir_or_eval_fn(
337 ecx: &mut InterpCx<'mir, 'tcx, Self>,
338 instance: ty::Instance<'tcx>,
339 args: &[OpTy<'tcx, Tag>],
340 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
341 unwind: Option<mir::BasicBlock>,
342 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
343 ecx.find_mir_or_eval_fn(instance, args, ret, unwind)
348 ecx: &mut InterpCx<'mir, 'tcx, Self>,
350 args: &[OpTy<'tcx, Tag>],
351 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
352 _unwind: Option<mir::BasicBlock>,
353 ) -> InterpResult<'tcx> {
354 ecx.call_dlsym(fn_val, args, ret)
359 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
360 instance: ty::Instance<'tcx>,
361 args: &[OpTy<'tcx, Tag>],
362 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
363 unwind: Option<mir::BasicBlock>,
364 ) -> InterpResult<'tcx> {
365 ecx.call_intrinsic(instance, args, ret, unwind)
370 ecx: &mut InterpCx<'mir, 'tcx, Self>,
371 msg: &mir::AssertMessage<'tcx>,
372 unwind: Option<mir::BasicBlock>,
373 ) -> InterpResult<'tcx> {
374 ecx.assert_panic(msg, unwind)
378 fn abort(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, !> {
379 throw_machine_stop!(TerminationInfo::Abort(None))
384 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
386 left: ImmTy<'tcx, Tag>,
387 right: ImmTy<'tcx, Tag>,
388 ) -> InterpResult<'tcx, (Scalar<Tag>, bool, ty::Ty<'tcx>)> {
389 ecx.binary_ptr_op(bin_op, left, right)
393 ecx: &mut InterpCx<'mir, 'tcx, Self>,
394 dest: PlaceTy<'tcx, Tag>,
395 ) -> InterpResult<'tcx> {
396 trace!("box_alloc for {:?}", dest.layout.ty);
397 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
398 // First argument: `size`.
399 // (`0` is allowed here -- this is expected to be handled by the lang item).
400 let size = Scalar::from_machine_usize(layout.size.bytes(), ecx);
402 // Second argument: `align`.
403 let align = Scalar::from_machine_usize(layout.align.abi.bytes(), ecx);
405 // Call the `exchange_malloc` lang item.
406 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
407 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
410 &[size.into(), align.into()],
412 // Don't do anything when we are done. The `statement()` function will increment
413 // the old stack frame's stmt counter to the next statement, which means that when
414 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
415 StackPopCleanup::None { cleanup: true },
420 fn thread_local_alloc_id(
421 ecx: &mut InterpCx<'mir, 'tcx, Self>,
423 ) -> InterpResult<'tcx, AllocId> {
424 ecx.get_or_create_thread_local_alloc_id(def_id)
427 fn adjust_global_const(
428 ecx: &InterpCx<'mir, 'tcx, Self>,
429 mut val: mir::interpret::ConstValue<'tcx>,
430 ) -> InterpResult<'tcx, mir::interpret::ConstValue<'tcx>> {
431 // FIXME: Remove this, do The Right Thing in `thread_local_alloc_id` instead.
432 ecx.remap_thread_local_alloc_ids(&mut val)?;
436 fn canonical_alloc_id(mem: &Memory<'mir, 'tcx, Self>, id: AllocId) -> AllocId {
438 // Figure out if this is an extern static, and if yes, which one.
439 let def_id = match tcx.get_global_alloc(id) {
440 Some(GlobalAlloc::Static(def_id)) if tcx.is_foreign_item(def_id) => def_id,
442 // No need to canonicalize anything.
446 let attrs = tcx.get_attrs(def_id);
447 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
449 None => tcx.item_name(def_id),
451 // Check if we know this one.
452 if let Some(canonical_id) = mem.extra.extern_statics.get(&link_name) {
453 trace!("canonical_alloc_id: {:?} ({}) -> {:?}", id, link_name, canonical_id);
456 // Return original id; `Memory::get_static_alloc` will throw an error.
461 fn init_allocation_extra<'b>(
462 memory_extra: &MemoryExtra,
464 alloc: Cow<'b, Allocation>,
465 kind: Option<MemoryKind<Self::MemoryKind>>,
466 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
467 if Some(id) == memory_extra.tracked_alloc_id {
468 register_diagnostic(NonHaltingDiagnostic::CreatedAlloc(id));
471 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
472 let alloc = alloc.into_owned();
473 let (stacks, base_tag) =
474 if let Some(stacked_borrows) = &memory_extra.stacked_borrows {
475 let (stacks, base_tag) =
476 Stacks::new_allocation(id, alloc.size, Rc::clone(stacked_borrows), kind);
477 (Some(stacks), base_tag)
479 // No stacks, no tag.
480 (None, Tag::Untagged)
482 let mut stacked_borrows = memory_extra.stacked_borrows.as_ref().map(|sb| sb.borrow_mut());
483 let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
485 if let Some(stacked_borrows) = &mut stacked_borrows {
486 // Only globals may already contain pointers at this point
487 assert_eq!(kind, MiriMemoryKind::Global.into());
488 stacked_borrows.global_base_ptr(alloc)
493 AllocExtra { stacked_borrows: stacks },
495 (Cow::Owned(alloc), base_tag)
499 fn before_deallocation(
500 memory_extra: &mut Self::MemoryExtra,
502 ) -> InterpResult<'tcx> {
503 if Some(id) == memory_extra.tracked_alloc_id {
504 register_diagnostic(NonHaltingDiagnostic::FreedAlloc(id));
511 fn tag_global_base_pointer(memory_extra: &MemoryExtra, id: AllocId) -> Self::PointerTag {
512 if let Some(stacked_borrows) = &memory_extra.stacked_borrows {
513 stacked_borrows.borrow_mut().global_base_ptr(id)
521 ecx: &mut InterpCx<'mir, 'tcx, Self>,
522 kind: mir::RetagKind,
523 place: PlaceTy<'tcx, Tag>,
524 ) -> InterpResult<'tcx> {
525 if ecx.memory.extra.stacked_borrows.is_some() {
526 ecx.retag(kind, place)
534 ecx: &mut InterpCx<'mir, 'tcx, Self>,
535 frame: Frame<'mir, 'tcx, Tag>,
536 ) -> InterpResult<'tcx, Frame<'mir, 'tcx, Tag, FrameData<'tcx>>> {
537 let stacked_borrows = ecx.memory.extra.stacked_borrows.as_ref();
538 let call_id = stacked_borrows.map_or(NonZeroU64::new(1).unwrap(), |stacked_borrows| {
539 stacked_borrows.borrow_mut().new_call()
541 let extra = FrameData { call_id, catch_unwind: None };
542 Ok(frame.with_extra(extra))
546 ecx: &'a InterpCx<'mir, 'tcx, Self>
547 ) -> &'a [Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>] {
548 ecx.active_thread_stack()
552 ecx: &'a mut InterpCx<'mir, 'tcx, Self>
553 ) -> &'a mut Vec<Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>> {
554 ecx.active_thread_stack_mut()
558 fn after_stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
559 if ecx.memory.extra.stacked_borrows.is_some() {
560 ecx.retag_return_place()
568 ecx: &mut InterpCx<'mir, 'tcx, Self>,
569 frame: Frame<'mir, 'tcx, Tag, FrameData<'tcx>>,
571 ) -> InterpResult<'tcx, StackPopJump> {
572 ecx.handle_stack_pop(frame.extra, unwinding)
577 memory: &Memory<'mir, 'tcx, Self>,
579 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
580 intptrcast::GlobalState::int_to_ptr(int, memory)
585 memory: &Memory<'mir, 'tcx, Self>,
586 ptr: Pointer<Self::PointerTag>,
587 ) -> InterpResult<'tcx, u64> {
588 intptrcast::GlobalState::ptr_to_int(ptr, memory)
592 impl AllocationExtra<Tag> for AllocExtra {
594 fn memory_read<'tcx>(
595 alloc: &Allocation<Tag, AllocExtra>,
598 ) -> InterpResult<'tcx> {
599 if let Some(stacked_borrows) = &alloc.extra.stacked_borrows {
600 stacked_borrows.memory_read(ptr, size)
607 fn memory_written<'tcx>(
608 alloc: &mut Allocation<Tag, AllocExtra>,
611 ) -> InterpResult<'tcx> {
612 if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
613 stacked_borrows.memory_written(ptr, size)
620 fn memory_deallocated<'tcx>(
621 alloc: &mut Allocation<Tag, AllocExtra>,
624 ) -> InterpResult<'tcx> {
625 if let Some(stacked_borrows) = &mut alloc.extra.stacked_borrows {
626 stacked_borrows.memory_deallocated(ptr, size)