1 //! Global machine state as well as implementation of the interpreter engine
6 use std::cell::RefCell;
8 use rand::rngs::StdRng;
11 use syntax::symbol::sym;
12 use rustc::hir::def_id::DefId;
13 use rustc::ty::{self, Ty, TyCtxt, layout::{Size, LayoutOf}};
18 // Some global facts about the emulated machine.
19 pub const PAGE_SIZE: u64 = 4*1024; // FIXME: adjust to target architecture
20 pub const STACK_ADDR: u64 = 32*PAGE_SIZE; // not really about the "stack", but where we start assigning integer addresses to allocations
21 pub const STACK_SIZE: u64 = 16*PAGE_SIZE; // whatever
22 pub const NUM_CPUS: u64 = 1;
24 /// Extra memory kinds
25 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
26 pub enum MiriMemoryKind {
27 /// `__rust_alloc` memory.
31 /// Windows `HeapAlloc` memory.
33 /// Part of env var emulation.
39 impl Into<MemoryKind<MiriMemoryKind>> for MiriMemoryKind {
41 fn into(self) -> MemoryKind<MiriMemoryKind> {
42 MemoryKind::Machine(self)
46 /// Extra per-allocation data
47 #[derive(Debug, Clone)]
48 pub struct AllocExtra {
49 /// Stacked Borrows state is only added if validation is enabled.
50 pub stacked_borrows: Option<stacked_borrows::AllocExtra>,
53 /// Extra global memory data
54 #[derive(Clone, Debug)]
55 pub struct MemoryExtra {
56 pub stacked_borrows: stacked_borrows::MemoryExtra,
57 pub intptrcast: intptrcast::MemoryExtra,
59 /// The random number generator used for resolving non-determinism.
60 pub(crate) rng: RefCell<StdRng>,
62 /// Whether to enforce the validity invariant.
63 pub(crate) validate: bool,
67 pub fn new(rng: StdRng, validate: bool) -> Self {
69 stacked_borrows: Default::default(),
70 intptrcast: Default::default(),
71 rng: RefCell::new(rng),
77 /// The machine itself.
78 pub struct Evaluator<'tcx> {
79 /// Environment variables set by `setenv`.
80 /// Miri does not expose env vars from the host to the emulated program.
81 pub(crate) env_vars: EnvVars,
83 /// Program arguments (`Option` because we can only initialize them after creating the ecx).
84 /// These are *pointers* to argc/argv because macOS.
85 /// We also need the full command line as one string because of Windows.
86 pub(crate) argc: Option<Pointer<Tag>>,
87 pub(crate) argv: Option<Pointer<Tag>>,
88 pub(crate) cmd_line: Option<Pointer<Tag>>,
91 pub(crate) last_error: u32,
94 pub(crate) tls: TlsData<'tcx>,
96 /// If enabled, the `env_vars` field is populated with the host env vars during initialization
97 /// and random number generation is delegated to the host.
98 pub(crate) communicate: bool,
101 impl<'tcx> Evaluator<'tcx> {
102 pub(crate) fn new(communicate: bool) -> Self {
104 // `env_vars` could be initialized properly here if `Memory` were available before
105 // calling this method.
106 env_vars: EnvVars::default(),
111 tls: TlsData::default(),
117 /// A rustc InterpCx for Miri.
118 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
120 /// A little trait that's useful to be inherited by extension traits.
121 pub trait MiriEvalContextExt<'mir, 'tcx> {
122 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx>;
123 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx>;
125 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
127 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
131 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
136 /// Machine hook implementations.
137 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
138 type MemoryKinds = MiriMemoryKind;
140 type FrameExtra = stacked_borrows::CallId;
141 type MemoryExtra = MemoryExtra;
142 type AllocExtra = AllocExtra;
143 type PointerTag = Tag;
144 type ExtraFnVal = Dlsym;
146 type MemoryMap = MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
148 const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
150 const CHECK_ALIGN: bool = true;
153 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
154 ecx.memory().extra.validate
159 ecx: &mut InterpCx<'mir, 'tcx, Self>,
160 instance: ty::Instance<'tcx>,
161 args: &[OpTy<'tcx, Tag>],
162 dest: Option<PlaceTy<'tcx, Tag>>,
163 ret: Option<mir::BasicBlock>,
164 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
165 ecx.find_fn(instance, args, dest, ret)
170 ecx: &mut InterpCx<'mir, 'tcx, Self>,
172 args: &[OpTy<'tcx, Tag>],
173 dest: Option<PlaceTy<'tcx, Tag>>,
174 ret: Option<mir::BasicBlock>,
175 ) -> InterpResult<'tcx> {
176 ecx.call_dlsym(fn_val, args, dest, ret)
181 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
182 instance: ty::Instance<'tcx>,
183 args: &[OpTy<'tcx, Tag>],
184 dest: PlaceTy<'tcx, Tag>,
185 ) -> InterpResult<'tcx> {
186 ecx.call_intrinsic(instance, args, dest)
191 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
193 left: ImmTy<'tcx, Tag>,
194 right: ImmTy<'tcx, Tag>,
195 ) -> InterpResult<'tcx, (Scalar<Tag>, bool, Ty<'tcx>)> {
196 ecx.binary_ptr_op(bin_op, left, right)
200 ecx: &mut InterpCx<'mir, 'tcx, Self>,
201 dest: PlaceTy<'tcx, Tag>,
202 ) -> InterpResult<'tcx> {
203 trace!("box_alloc for {:?}", dest.layout.ty);
204 // Call the `exchange_malloc` lang item.
205 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
206 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
207 let malloc_mir = ecx.load_mir(malloc.def, None)?;
208 ecx.push_stack_frame(
213 // Don't do anything when we are done. The `statement()` function will increment
214 // the old stack frame's stmt counter to the next statement, which means that when
215 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
216 StackPopCleanup::None { cleanup: true },
219 let mut args = ecx.frame().body.args_iter();
220 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
222 // First argument: `size`.
223 // (`0` is allowed here -- this is expected to be handled by the lang item).
224 let arg = ecx.local_place(args.next().unwrap())?;
225 let size = layout.size.bytes();
226 ecx.write_scalar(Scalar::from_uint(size, arg.layout.size), arg)?;
228 // Second argument: `align`.
229 let arg = ecx.local_place(args.next().unwrap())?;
230 let align = layout.align.abi.bytes();
231 ecx.write_scalar(Scalar::from_uint(align, arg.layout.size), arg)?;
233 // No more arguments.
235 args.next().is_none(),
236 "`exchange_malloc` lang item has more arguments than expected"
241 fn find_foreign_static(
244 ) -> InterpResult<'tcx, Cow<'tcx, Allocation>> {
245 let attrs = tcx.get_attrs(def_id);
246 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
247 Some(name) => name.as_str(),
248 None => tcx.item_name(def_id).as_str(),
251 let alloc = match &*link_name {
252 "__cxa_thread_atexit_impl" => {
253 // This should be all-zero, pointer-sized.
254 let size = tcx.data_layout.pointer_size;
255 let data = vec![0; size.bytes() as usize];
256 Allocation::from_bytes(&data, tcx.data_layout.pointer_align.abi)
258 _ => throw_unsup_format!("can't access foreign static: {}", link_name),
260 Ok(Cow::Owned(alloc))
264 fn before_terminator(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx>
266 // We are not interested in detecting loops.
270 fn tag_allocation<'b>(
271 memory_extra: &MemoryExtra,
273 alloc: Cow<'b, Allocation>,
274 kind: Option<MemoryKind<Self::MemoryKinds>>,
275 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
276 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
277 let alloc = alloc.into_owned();
278 let (stacks, base_tag) = if !memory_extra.validate {
279 (None, Tag::Untagged)
281 let (stacks, base_tag) = Stacks::new_allocation(
284 Rc::clone(&memory_extra.stacked_borrows),
287 (Some(stacks), base_tag)
289 let mut stacked_borrows = memory_extra.stacked_borrows.borrow_mut();
290 let alloc: Allocation<Tag, Self::AllocExtra> = alloc.with_tags_and_extra(
291 |alloc| if !memory_extra.validate {
294 // Only statics may already contain pointers at this point
295 assert_eq!(kind, MiriMemoryKind::Static.into());
296 stacked_borrows.static_base_ptr(alloc)
299 stacked_borrows: stacks,
302 (Cow::Owned(alloc), base_tag)
306 fn tag_static_base_pointer(
307 memory_extra: &MemoryExtra,
309 ) -> Self::PointerTag {
310 if !memory_extra.validate {
313 memory_extra.stacked_borrows.borrow_mut().static_base_ptr(id)
319 ecx: &mut InterpCx<'mir, 'tcx, Self>,
320 kind: mir::RetagKind,
321 place: PlaceTy<'tcx, Tag>,
322 ) -> InterpResult<'tcx> {
323 if !Self::enforce_validity(ecx) {
327 ecx.retag(kind, place)
333 ecx: &mut InterpCx<'mir, 'tcx, Self>,
334 ) -> InterpResult<'tcx, stacked_borrows::CallId> {
335 Ok(ecx.memory().extra.stacked_borrows.borrow_mut().new_call())
340 ecx: &mut InterpCx<'mir, 'tcx, Self>,
341 extra: stacked_borrows::CallId,
342 ) -> InterpResult<'tcx> {
343 Ok(ecx.memory().extra.stacked_borrows.borrow_mut().end_call(extra))
348 memory: &Memory<'mir, 'tcx, Self>,
350 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
351 intptrcast::GlobalState::int_to_ptr(int, memory)
356 memory: &Memory<'mir, 'tcx, Self>,
357 ptr: Pointer<Self::PointerTag>,
358 ) -> InterpResult<'tcx, u64> {
359 intptrcast::GlobalState::ptr_to_int(ptr, memory)
363 impl AllocationExtra<Tag> for AllocExtra {
365 fn memory_read<'tcx>(
366 alloc: &Allocation<Tag, AllocExtra>,
369 ) -> InterpResult<'tcx> {
370 if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
371 stacked_borrows.memory_read(ptr, size)
378 fn memory_written<'tcx>(
379 alloc: &mut Allocation<Tag, AllocExtra>,
382 ) -> InterpResult<'tcx> {
383 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
384 stacked_borrows.memory_written(ptr, size)
391 fn memory_deallocated<'tcx>(
392 alloc: &mut Allocation<Tag, AllocExtra>,
395 ) -> InterpResult<'tcx> {
396 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
397 stacked_borrows.memory_deallocated(ptr, size)
404 impl MayLeak for MiriMemoryKind {
406 fn may_leak(self) -> bool {
407 use self::MiriMemoryKind::*;
409 Rust | C | WinHeap => false,
410 Env | Static => true,