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, layout::{Size, LayoutOf}, TyCtxt};
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 pub(crate) communicate: bool,
100 impl<'tcx> Evaluator<'tcx> {
101 pub(crate) fn new(communicate: bool) -> Self {
103 // `env_vars` could be initialized properly here if `Memory` were available before
104 // calling this method.
105 env_vars: EnvVars::default(),
110 tls: TlsData::default(),
116 /// A rustc InterpCx for Miri.
117 pub type MiriEvalContext<'mir, 'tcx> = InterpCx<'mir, 'tcx, Evaluator<'tcx>>;
119 /// A little trait that's useful to be inherited by extension traits.
120 pub trait MiriEvalContextExt<'mir, 'tcx> {
121 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx>;
122 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx>;
124 impl<'mir, 'tcx> MiriEvalContextExt<'mir, 'tcx> for MiriEvalContext<'mir, 'tcx> {
126 fn eval_context_ref(&self) -> &MiriEvalContext<'mir, 'tcx> {
130 fn eval_context_mut(&mut self) -> &mut MiriEvalContext<'mir, 'tcx> {
135 /// Machine hook implementations.
136 impl<'mir, 'tcx> Machine<'mir, 'tcx> for Evaluator<'tcx> {
137 type MemoryKinds = MiriMemoryKind;
139 type FrameExtra = stacked_borrows::CallId;
140 type MemoryExtra = MemoryExtra;
141 type AllocExtra = AllocExtra;
142 type PointerTag = Tag;
143 type ExtraFnVal = Dlsym;
145 type MemoryMap = MonoHashMap<AllocId, (MemoryKind<MiriMemoryKind>, Allocation<Tag, Self::AllocExtra>)>;
147 const STATIC_KIND: Option<MiriMemoryKind> = Some(MiriMemoryKind::Static);
149 const CHECK_ALIGN: bool = true;
152 fn enforce_validity(ecx: &InterpCx<'mir, 'tcx, Self>) -> bool {
153 ecx.memory().extra.validate
158 ecx: &mut InterpCx<'mir, 'tcx, Self>,
159 instance: ty::Instance<'tcx>,
160 args: &[OpTy<'tcx, Tag>],
161 dest: Option<PlaceTy<'tcx, Tag>>,
162 ret: Option<mir::BasicBlock>,
163 ) -> InterpResult<'tcx, Option<&'mir mir::Body<'tcx>>> {
164 ecx.find_fn(instance, args, dest, ret)
169 ecx: &mut InterpCx<'mir, 'tcx, Self>,
171 args: &[OpTy<'tcx, Tag>],
172 dest: Option<PlaceTy<'tcx, Tag>>,
173 ret: Option<mir::BasicBlock>,
174 ) -> InterpResult<'tcx> {
175 ecx.call_dlsym(fn_val, args, dest, ret)
180 ecx: &mut rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
181 instance: ty::Instance<'tcx>,
182 args: &[OpTy<'tcx, Tag>],
183 dest: PlaceTy<'tcx, Tag>,
184 ) -> InterpResult<'tcx> {
185 ecx.call_intrinsic(instance, args, dest)
190 ecx: &rustc_mir::interpret::InterpCx<'mir, 'tcx, Self>,
192 left: ImmTy<'tcx, Tag>,
193 right: ImmTy<'tcx, Tag>,
194 ) -> InterpResult<'tcx, (Scalar<Tag>, bool)> {
195 ecx.binary_ptr_op(bin_op, left, right)
199 ecx: &mut InterpCx<'mir, 'tcx, Self>,
200 dest: PlaceTy<'tcx, Tag>,
201 ) -> InterpResult<'tcx> {
202 trace!("box_alloc for {:?}", dest.layout.ty);
203 // Call the `exchange_malloc` lang item.
204 let malloc = ecx.tcx.lang_items().exchange_malloc_fn().unwrap();
205 let malloc = ty::Instance::mono(ecx.tcx.tcx, malloc);
206 let malloc_mir = ecx.load_mir(malloc.def)?;
207 ecx.push_stack_frame(
212 // Don't do anything when we are done. The `statement()` function will increment
213 // the old stack frame's stmt counter to the next statement, which means that when
214 // `exchange_malloc` returns, we go on evaluating exactly where we want to be.
215 StackPopCleanup::None { cleanup: true },
218 let mut args = ecx.frame().body.args_iter();
219 let layout = ecx.layout_of(dest.layout.ty.builtin_deref(false).unwrap().ty)?;
221 // First argument: `size`.
222 // (`0` is allowed here -- this is expected to be handled by the lang item).
223 let arg = ecx.local_place(args.next().unwrap())?;
224 let size = layout.size.bytes();
225 ecx.write_scalar(Scalar::from_uint(size, arg.layout.size), arg)?;
227 // Second argument: `align`.
228 let arg = ecx.local_place(args.next().unwrap())?;
229 let align = layout.align.abi.bytes();
230 ecx.write_scalar(Scalar::from_uint(align, arg.layout.size), arg)?;
232 // No more arguments.
234 args.next().is_none(),
235 "`exchange_malloc` lang item has more arguments than expected"
240 fn find_foreign_static(
243 ) -> InterpResult<'tcx, Cow<'tcx, Allocation>> {
244 let attrs = tcx.get_attrs(def_id);
245 let link_name = match attr::first_attr_value_str_by_name(&attrs, sym::link_name) {
246 Some(name) => name.as_str(),
247 None => tcx.item_name(def_id).as_str(),
250 let alloc = match link_name.get() {
251 "__cxa_thread_atexit_impl" => {
252 // This should be all-zero, pointer-sized.
253 let size = tcx.data_layout.pointer_size;
254 let data = vec![0; size.bytes() as usize];
255 Allocation::from_bytes(&data, tcx.data_layout.pointer_align.abi)
257 _ => throw_unsup_format!("can't access foreign static: {}", link_name),
259 Ok(Cow::Owned(alloc))
263 fn before_terminator(_ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx>
265 // We are not interested in detecting loops.
269 fn tag_allocation<'b>(
270 memory_extra: &MemoryExtra,
272 alloc: Cow<'b, Allocation>,
273 kind: Option<MemoryKind<Self::MemoryKinds>>,
274 ) -> (Cow<'b, Allocation<Self::PointerTag, Self::AllocExtra>>, Self::PointerTag) {
275 let kind = kind.expect("we set our STATIC_KIND so this cannot be None");
276 let alloc = alloc.into_owned();
277 let (stacks, base_tag) = if !memory_extra.validate {
278 (None, Tag::Untagged)
280 let (stacks, base_tag) = Stacks::new_allocation(
282 Size::from_bytes(alloc.bytes.len() as u64),
283 Rc::clone(&memory_extra.stacked_borrows),
286 (Some(stacks), base_tag)
288 if kind != MiriMemoryKind::Static.into() {
289 assert!(alloc.relocations.is_empty(), "Only statics can come initialized with inner pointers");
290 // Now we can rely on the inner pointers being static, too.
292 let mut stacked_borrows = memory_extra.stacked_borrows.borrow_mut();
293 let alloc: Allocation<Tag, Self::AllocExtra> = Allocation {
295 relocations: Relocations::from_presorted(
296 alloc.relocations.iter()
297 // The allocations in the relocations (pointers stored *inside* this allocation)
298 // all get the base pointer tag.
299 .map(|&(offset, ((), alloc))| {
300 let tag = if !memory_extra.validate {
303 stacked_borrows.static_base_ptr(alloc)
305 (offset, (tag, alloc))
309 undef_mask: alloc.undef_mask,
311 mutability: alloc.mutability,
313 stacked_borrows: stacks,
316 (Cow::Owned(alloc), base_tag)
320 fn tag_static_base_pointer(
321 memory_extra: &MemoryExtra,
323 ) -> Self::PointerTag {
324 if !memory_extra.validate {
327 memory_extra.stacked_borrows.borrow_mut().static_base_ptr(id)
333 ecx: &mut InterpCx<'mir, 'tcx, Self>,
334 kind: mir::RetagKind,
335 place: PlaceTy<'tcx, Tag>,
336 ) -> InterpResult<'tcx> {
337 if !Self::enforce_validity(ecx) {
341 ecx.retag(kind, place)
347 ecx: &mut InterpCx<'mir, 'tcx, Self>,
348 ) -> InterpResult<'tcx, stacked_borrows::CallId> {
349 Ok(ecx.memory().extra.stacked_borrows.borrow_mut().new_call())
354 ecx: &mut InterpCx<'mir, 'tcx, Self>,
355 extra: stacked_borrows::CallId,
356 ) -> InterpResult<'tcx> {
357 Ok(ecx.memory().extra.stacked_borrows.borrow_mut().end_call(extra))
362 memory: &Memory<'mir, 'tcx, Self>,
364 ) -> InterpResult<'tcx, Pointer<Self::PointerTag>> {
365 intptrcast::GlobalState::int_to_ptr(int, memory)
370 memory: &Memory<'mir, 'tcx, Self>,
371 ptr: Pointer<Self::PointerTag>,
372 ) -> InterpResult<'tcx, u64> {
373 intptrcast::GlobalState::ptr_to_int(ptr, memory)
377 impl AllocationExtra<Tag> for AllocExtra {
379 fn memory_read<'tcx>(
380 alloc: &Allocation<Tag, AllocExtra>,
383 ) -> InterpResult<'tcx> {
384 if let Some(ref stacked_borrows) = alloc.extra.stacked_borrows {
385 stacked_borrows.memory_read(ptr, size)
392 fn memory_written<'tcx>(
393 alloc: &mut Allocation<Tag, AllocExtra>,
396 ) -> InterpResult<'tcx> {
397 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
398 stacked_borrows.memory_written(ptr, size)
405 fn memory_deallocated<'tcx>(
406 alloc: &mut Allocation<Tag, AllocExtra>,
409 ) -> InterpResult<'tcx> {
410 if let Some(ref mut stacked_borrows) = alloc.extra.stacked_borrows {
411 stacked_borrows.memory_deallocated(ptr, size)
418 impl MayLeak for MiriMemoryKind {
420 fn may_leak(self) -> bool {
421 use self::MiriMemoryKind::*;
423 Rust | C | WinHeap => false,
424 Env | Static => true,