1 //! Global machine state as well as implementation of the interpreter engine
5 use std::cell::RefCell;
6 use std::num::NonZeroU64;
9 use rand::rngs::StdRng;
11 use rustc_data_structures::fx::FxHashMap;
15 layout::{LayoutOf, Size},
19 use rustc_span::{source_map::Span, symbol::{sym, Symbol}};
23 // Some global facts about the emulated machine.
24 pub const PAGE_SIZE: u64 = 4 * 1024; // FIXME: adjust to target architecture
25 pub const STACK_ADDR: u64 = 32 * PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
26 pub const STACK_SIZE: u64 = 16 * PAGE_SIZE; // whatever
27 pub const NUM_CPUS: u64 = 1;
29 /// Extra data stored with each stack frame
31 pub struct FrameData<'tcx> {
32 /// Extra data for Stacked Borrows.
33 pub call_id: stacked_borrows::CallId,
35 /// If this is Some(), then this is a special "catch unwind" frame (the frame of the closure
36 /// called by `__rustc_maybe_catch_panic`). When this frame is popped during unwinding a panic,
37 /// we stop unwinding, use the `CatchUnwindData` to
38 /// store the panic payload, and continue execution in the parent frame.
39 pub catch_panic: 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 env vars and args, errno, extern statics and other parts of the machine-managed environment.
57 impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
59 fn into(self) -> MemoryKind<MiriMemoryKind> {
60 MemoryKind::Machine(self)
64 /// Extra per-allocation data
65 #[derive(Debug, Clone)]
66 pub struct AllocExtra {
67 /// Stacked Borrows state is only added if it is enabled.
68 pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
71 /// Extra global memory data
72 #[derive(Clone, Debug)]
73 pub struct MemoryExtra {
74 pub stacked_borrows: Option<stacked_borrows::MemoryExtra>,
75 pub intptrcast: intptrcast::MemoryExtra,
77 /// Mapping extern static names to their canonical allocation.
78 extern_statics: FxHashMap<Symbol, AllocId>,
80 /// The random number generator used for resolving non-determinism.
81 /// Needs to be queried by ptr_to_int, hence needs interior mutability.
82 pub(crate) rng: RefCell<StdRng>,
84 /// An allocation ID to report when it is being allocated
85 /// (helps for debugging memory leaks).
86 tracked_alloc_id: Option<AllocId>,
90 pub fn new(rng: StdRng, stacked_borrows: bool, tracked_pointer_tag: Option<PtrId>, tracked_alloc_id: Option<AllocId>) -> Self {
91 let stacked_borrows = if stacked_borrows {
92 Some(Rc::new(RefCell::new(stacked_borrows::GlobalState::new(tracked_pointer_tag))))
98 intptrcast: Default::default(),
99 extern_statics: FxHashMap::default(),
100 rng: RefCell::new(rng),
105 /// Sets up the "extern statics" for this machine.
106 pub fn init_extern_statics<'tcx, 'mir>(
107 this: &mut MiriEvalContext<'mir, 'tcx>,
108 ) -> InterpResult<'tcx> {
109 let target_os = this.tcx.sess.target.target.target_os.as_str();
112 // "__cxa_thread_atexit_impl"
113 // This should be all-zero, pointer-sized.
114 let layout = this.layout_of(this.tcx.types.usize)?;
115 let place = this.allocate(layout, MiriMemoryKind::Machine.into());
116 this.write_scalar(Scalar::from_machine_usize(0, &*this.tcx), place.into())?;
120 .insert(Symbol::intern("__cxa_thread_atexit_impl"), place.ptr.assert_ptr().alloc_id)
126 .insert(Symbol::intern("environ"), this.machine.env_vars.environ.unwrap().ptr.assert_ptr().alloc_id)
129 _ => {} // No "extern statics" supported on this platform
135 /// The machine itself.
136 pub struct Evaluator<'tcx> {
137 /// Environment variables set by `setenv`.
138 /// Miri does not expose env vars from the host to the emulated program.
139 pub(crate) env_vars: EnvVars<'tcx>,
141 /// Program arguments (`Option` because we can only initialize them after creating the ecx).
142 /// These are *pointers* to argc/argv because macOS.
143 /// We also need the full command line as one string because of Windows.
144 pub(crate) argc: Option<Scalar<Tag>>,
145 pub(crate) argv: Option<Scalar<Tag>>,
146 pub(crate) cmd_line: Option<Scalar<Tag>>,
148 /// Last OS error location in memory. It is a 32-bit integer.
149 pub(crate) last_error: Option<MPlaceTy<'tcx, Tag>>,
152 pub(crate) tls: TlsData<'tcx>,
154 /// If enabled, the `env_vars` field is populated with the host env vars during initialization
155 /// and random number generation is delegated to the host.
156 pub(crate) communicate: bool,
158 /// Whether to enforce the validity invariant.
159 pub(crate) validate: bool,
161 pub(crate) file_handler: FileHandler,
162 pub(crate) dir_handler: DirHandler,
164 /// The temporary used for storing the argument of
165 /// the call to `miri_start_panic` (the panic payload) when unwinding.
166 pub(crate) panic_payload: Option<ImmTy<'tcx, Tag>>,
169 impl<'tcx> Evaluator<'tcx> {
170 pub(crate) fn new(communicate: bool, validate: bool) -> Self {
172 // `env_vars` could be initialized properly here if `Memory` were available before
173 // calling this method.
174 env_vars: EnvVars::default(),
179 tls: TlsData::default(),
182 file_handler: Default::default(),
183 dir_handler: Default::default(),
189 /// A rustc InterpCx for Miri.
190 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
192 /// A little trait that's useful to be inherited by extension traits.
193 pub trait MiriEvalContextExt<'mir, 'tcx> {
194 fn eval_context_ref<'a>(&'a self) -> &'a MiriEvalContext<'mir, 'tcx>;
195 fn eval_context_mut<'a>(&'a mut self) -> &'a mut MiriEvalContext<'mir, 'tcx>;
197 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
199 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
203 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
208 /// Machine hook implementations.
209 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
210 type MemoryKinds = MiriMemoryKind;
212 type FrameExtra = FrameData<'tcx>;
213 type MemoryExtra = MemoryExtra;
214 type AllocExtra = AllocExtra;
215 type PointerTag = Tag;
216 type ExtraFnVal = Dlsym;
219 MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
221 const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
223 const CHECK_ALIGN: bool = true;
226 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
231 fn find_mir_or_eval_fn(
232 ecx: &mut InterpCx<'mir, 'tcx, Self>,
234 instance: ty::Instance<'tcx>,
235 args: &[OpTy<'tcx, Tag>],
236 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
237 unwind: Option<mir::BasicBlock>,
238 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
239 ecx.find_mir_or_eval_fn(instance, args, ret, unwind)
244 ecx: &mut InterpCx<'mir, 'tcx, Self>,
246 args: &[OpTy<'tcx, Tag>],
247 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
248 _unwind: Option<mir::BasicBlock>,
249 ) -> InterpResult<'tcx> {
250 ecx.call_dlsym(fn_val, args, ret)
255 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
257 instance: ty::Instance<'tcx>,
258 args: &[OpTy<'tcx, Tag>],
259 ret: Option<(PlaceTy<'tcx, Tag>, mir::BasicBlock)>,
260 unwind: Option<mir::BasicBlock>,
261 ) -> InterpResult<'tcx> {
262 ecx.call_intrinsic(span, instance, args, ret, unwind)
267 ecx: &mut InterpCx<'mir, 'tcx, Self>,
268 msg: &mir::AssertMessage<'tcx>,
269 unwind: Option<mir::BasicBlock>,
270 ) -> InterpResult<'tcx> {
271 ecx.assert_panic(msg, unwind)
276 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
278 left: ImmTy<'tcx, Tag>,
279 right: ImmTy<'tcx, Tag>,
280 ) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
281 ecx.binary_ptr_op(bin_op, left, right)
285 ecx: &mut InterpCx<'mir, 'tcx, Self>,
286 dest: PlaceTy<'tcx, Tag>,
287 ) -> InterpResult<'tcx> {
288 trace!("box_alloc for {:?}", dest.layout.ty);
289 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
290 // First argument: `size`.
291 // (`0` is allowed here -- this is expected to be handled by the lang item).
292 let size = Scalar::from_uint(layout.size.bytes(), ecx.pointer_size());
294 // Second argument: `align`.
295 let align = Scalar::from_uint(layout.align.abi.bytes(), ecx.pointer_size());
297 // Call the `exchange_malloc` lang item.
298 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
299 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
302 &[size.into(), align.into()],
304 // Don't do anything when we are done. The `statement()` function will increment
305 // the old stack frame's stmt counter to the next statement, which means that when
306 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
307 StackPopCleanup::None { cleanup: true },
312 fn canonical_alloc_id(mem: &Memory<'mir, 'tcx, Self>, id: AllocId) -> AllocId {
314 // Figure out if this is an extern static, and if yes, which one.
315 let def_id = match tcx.alloc_map.lock().get(id) {
316 Some(GlobalAlloc::Static(def_id)) if tcx.is_foreign_item(def_id) => def_id,
318 // No need to canonicalize anything.
322 let attrs = tcx.get_attrs(def_id);
323 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
325 None => tcx.item_name(def_id),
327 // Check if we know this one.
328 if let Some(canonical_id) = mem.extra.extern_statics.get(&link_name) {
329 trace!("canonical_alloc_id: {:?} ({}) -> {:?}", id, link_name, canonical_id);
332 // Return original id; `Memory::get_static_alloc` will throw an error.
337 fn init_allocation_extra<'b>(
338 memory_extra: &MemoryExtra,
340 alloc: Cow<'b, Allocation>,
341 kind: Option<MemoryKind<Self::MemoryKinds>>,
342 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
343 if Some(id) == memory_extra.tracked_alloc_id {
344 register_diagnostic(NonHaltingDiagnostic::CreatedAlloc(id));
347 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
348 let alloc = alloc.into_owned();
349 let (stacks, base_tag) =
350 if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
351 let (stacks, base_tag) =
352 Stacks::new_allocation(id, alloc.size, Rc::clone(stacked_borrows), kind);
353 (Some(stacks), base_tag)
355 // No stacks, no tag.
356 (None, Tag::Untagged)
358 let mut stacked_borrows = memory_extra.stacked_borrows.as_ref().map(|sb| sb.borrow_mut());
359 let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
361 if let Some(stacked_borrows) = stacked_borrows.as_mut() {
362 // Only statics may already contain pointers at this point
363 assert_eq!(kind, MiriMemoryKind::Static.into());
364 stacked_borrows.static_base_ptr(alloc)
369 AllocExtra { stacked_borrows: stacks },
371 (Cow::Owned(alloc), base_tag)
375 fn tag_static_base_pointer(memory_extra: &MemoryExtra, id: AllocId) -> Self::PointerTag {
376 if let Some(stacked_borrows) = memory_extra.stacked_borrows.as_ref() {
377 stacked_borrows.borrow_mut().static_base_ptr(id)
385 ecx: &mut InterpCx<'mir, 'tcx, Self>,
386 kind: mir::RetagKind,
387 place: PlaceTy<'tcx, Tag>,
388 ) -> InterpResult<'tcx> {
389 if ecx.memory.extra.stacked_borrows.is_none() {
393 ecx.retag(kind, place)
398 fn stack_push(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx, FrameData<'tcx>> {
399 let stacked_borrows = ecx.memory.extra.stacked_borrows.as_ref();
400 let call_id = stacked_borrows.map_or(NonZeroU64::new(1).unwrap(), |stacked_borrows| {
401 stacked_borrows.borrow_mut().new_call()
403 Ok(FrameData { call_id, catch_panic: None })
408 ecx: &mut InterpCx<'mir, 'tcx, Self>,
409 extra: FrameData<'tcx>,
411 ) -> InterpResult<'tcx, StackPopInfo> {
412 ecx.handle_stack_pop(extra, unwinding)
417 memory: &Memory<'mir, 'tcx, Self>,
419 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
420 intptrcast::GlobalState::int_to_ptr(int, memory)
425 memory: &Memory<'mir, 'tcx, Self>,
426 ptr: Pointer<Self::PointerTag>,
427 ) -> InterpResult<'tcx, u64> {
428 intptrcast::GlobalState::ptr_to_int(ptr, memory)
432 impl AllocationExtra<Tag> for AllocExtra {
434 fn memory_read<'tcx>(
435 alloc: &Allocation<Tag, AllocExtra>,
438 ) -> InterpResult<'tcx> {
439 if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
440 stacked_borrows.memory_read(ptr, size)
447 fn memory_written<'tcx>(
448 alloc: &mut Allocation<Tag, AllocExtra>,
451 ) -> InterpResult<'tcx> {
452 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
453 stacked_borrows.memory_written(ptr, size)
460 fn memory_deallocated<'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_deallocated(ptr, size)
473 impl MayLeak for MiriMemoryKind {
475 fn may_leak(self) -> bool {
476 use self::MiriMemoryKind::*;
478 Rust | C | WinHeap => false,
479 Machine | Static => true,