| //! The memory subsystem. |
| //! |
| //! Generally, we use `Pointer` to denote memory addresses. However, some operations |
| //! have a "size"-like parameter, and they take `Scalar` for the address because |
| //! if the size is 0, then the pointer can also be a (properly aligned, non-NULL) |
| //! integer. It is crucial that these operations call `check_align` *before* |
| //! short-circuiting the empty case! |
| |
| use std::collections::VecDeque; |
| use std::ptr; |
| use std::borrow::Cow; |
| |
| use rustc::ty::{self, Instance, ParamEnv, query::TyCtxtAt}; |
| use rustc::ty::layout::{Align, TargetDataLayout, Size, HasDataLayout}; |
| use rustc_data_structures::fx::{FxHashSet, FxHashMap}; |
| |
| use syntax::ast::Mutability; |
| |
| use super::{ |
| Pointer, AllocId, Allocation, GlobalId, AllocationExtra, |
| InterpResult, Scalar, InterpError, GlobalAlloc, PointerArithmetic, |
| Machine, AllocMap, MayLeak, ErrorHandled, CheckInAllocMsg, |
| }; |
| |
| #[derive(Debug, PartialEq, Eq, Copy, Clone, Hash)] |
| pub enum MemoryKind<T> { |
| /// Error if deallocated except during a stack pop |
| Stack, |
| /// Error if ever deallocated |
| Vtable, |
| /// Additional memory kinds a machine wishes to distinguish from the builtin ones |
| Machine(T), |
| } |
| |
| impl<T: MayLeak> MayLeak for MemoryKind<T> { |
| #[inline] |
| fn may_leak(self) -> bool { |
| match self { |
| MemoryKind::Stack => false, |
| MemoryKind::Vtable => true, |
| MemoryKind::Machine(k) => k.may_leak() |
| } |
| } |
| } |
| |
| /// Used by `get_size_and_align` to indicate whether the allocation needs to be live. |
| #[derive(Debug, Copy, Clone)] |
| pub enum AllocCheck { |
| /// Allocation must be live and not a function pointer. |
| Dereferencable, |
| /// Allocations needs to be live, but may be a function pointer. |
| Live, |
| /// Allocation may be dead. |
| MaybeDead, |
| } |
| |
| // `Memory` has to depend on the `Machine` because some of its operations |
| // (e.g., `get`) call a `Machine` hook. |
| pub struct Memory<'mir, 'tcx, M: Machine<'mir, 'tcx>> { |
| /// Allocations local to this instance of the miri engine. The kind |
| /// helps ensure that the same mechanism is used for allocation and |
| /// deallocation. When an allocation is not found here, it is a |
| /// static and looked up in the `tcx` for read access. Some machines may |
| /// have to mutate this map even on a read-only access to a static (because |
| /// they do pointer provenance tracking and the allocations in `tcx` have |
| /// the wrong type), so we let the machine override this type. |
| /// Either way, if the machine allows writing to a static, doing so will |
| /// create a copy of the static allocation here. |
| // FIXME: this should not be public, but interning currently needs access to it |
| pub(super) alloc_map: M::MemoryMap, |
| |
| /// To be able to compare pointers with NULL, and to check alignment for accesses |
| /// to ZSTs (where pointers may dangle), we keep track of the size even for allocations |
| /// that do not exist any more. |
| pub(super) dead_alloc_map: FxHashMap<AllocId, (Size, Align)>, |
| |
| /// Extra data added by the machine. |
| pub extra: M::MemoryExtra, |
| |
| /// Lets us implement `HasDataLayout`, which is awfully convenient. |
| pub(super) tcx: TyCtxtAt<'tcx>, |
| } |
| |
| impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> HasDataLayout for Memory<'mir, 'tcx, M> { |
| #[inline] |
| fn data_layout(&self) -> &TargetDataLayout { |
| &self.tcx.data_layout |
| } |
| } |
| |
| // FIXME: Really we shouldn't clone memory, ever. Snapshot machinery should instead |
| // carefully copy only the reachable parts. |
| impl<'mir, 'tcx, M> Clone for Memory<'mir, 'tcx, M> |
| where |
| M: Machine<'mir, 'tcx, PointerTag = (), AllocExtra = (), MemoryExtra = ()>, |
| M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation)>, |
| { |
| fn clone(&self) -> Self { |
| Memory { |
| alloc_map: self.alloc_map.clone(), |
| dead_alloc_map: self.dead_alloc_map.clone(), |
| extra: (), |
| tcx: self.tcx, |
| } |
| } |
| } |
| |
| impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { |
| pub fn new(tcx: TyCtxtAt<'tcx>) -> Self { |
| Memory { |
| alloc_map: M::MemoryMap::default(), |
| dead_alloc_map: FxHashMap::default(), |
| extra: M::MemoryExtra::default(), |
| tcx, |
| } |
| } |
| |
| #[inline] |
| pub fn tag_static_base_pointer(&self, ptr: Pointer) -> Pointer<M::PointerTag> { |
| ptr.with_tag(M::tag_static_base_pointer(ptr.alloc_id, &self)) |
| } |
| |
| pub fn create_fn_alloc(&mut self, instance: Instance<'tcx>) -> Pointer<M::PointerTag> { |
| let id = self.tcx.alloc_map.lock().create_fn_alloc(instance); |
| self.tag_static_base_pointer(Pointer::from(id)) |
| } |
| |
| pub fn allocate( |
| &mut self, |
| size: Size, |
| align: Align, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> Pointer<M::PointerTag> { |
| let alloc = Allocation::undef(size, align); |
| self.allocate_with(alloc, kind) |
| } |
| |
| pub fn allocate_static_bytes( |
| &mut self, |
| bytes: &[u8], |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> Pointer<M::PointerTag> { |
| let alloc = Allocation::from_byte_aligned_bytes(bytes); |
| self.allocate_with(alloc, kind) |
| } |
| |
| pub fn allocate_with( |
| &mut self, |
| alloc: Allocation, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> Pointer<M::PointerTag> { |
| let id = self.tcx.alloc_map.lock().reserve(); |
| let (alloc, tag) = M::tag_allocation(id, Cow::Owned(alloc), Some(kind), &self); |
| self.alloc_map.insert(id, (kind, alloc.into_owned())); |
| Pointer::from(id).with_tag(tag) |
| } |
| |
| pub fn reallocate( |
| &mut self, |
| ptr: Pointer<M::PointerTag>, |
| old_size: Size, |
| old_align: Align, |
| new_size: Size, |
| new_align: Align, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> InterpResult<'tcx, Pointer<M::PointerTag>> { |
| if ptr.offset.bytes() != 0 { |
| return err!(ReallocateNonBasePtr); |
| } |
| |
| // For simplicities' sake, we implement reallocate as "alloc, copy, dealloc". |
| // This happens so rarely, the perf advantage is outweighed by the maintenance cost. |
| let new_ptr = self.allocate(new_size, new_align, kind); |
| self.copy( |
| ptr.into(), |
| old_align, |
| new_ptr.into(), |
| new_align, |
| old_size.min(new_size), |
| /*nonoverlapping*/ true, |
| )?; |
| self.deallocate(ptr, Some((old_size, old_align)), kind)?; |
| |
| Ok(new_ptr) |
| } |
| |
| /// Deallocate a local, or do nothing if that local has been made into a static |
| pub fn deallocate_local(&mut self, ptr: Pointer<M::PointerTag>) -> InterpResult<'tcx> { |
| // The allocation might be already removed by static interning. |
| // This can only really happen in the CTFE instance, not in miri. |
| if self.alloc_map.contains_key(&ptr.alloc_id) { |
| self.deallocate(ptr, None, MemoryKind::Stack) |
| } else { |
| Ok(()) |
| } |
| } |
| |
| pub fn deallocate( |
| &mut self, |
| ptr: Pointer<M::PointerTag>, |
| size_and_align: Option<(Size, Align)>, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> InterpResult<'tcx> { |
| trace!("deallocating: {}", ptr.alloc_id); |
| |
| if ptr.offset.bytes() != 0 { |
| return err!(DeallocateNonBasePtr); |
| } |
| |
| let (alloc_kind, mut alloc) = match self.alloc_map.remove(&ptr.alloc_id) { |
| Some(alloc) => alloc, |
| None => { |
| // Deallocating static memory -- always an error |
| return match self.tcx.alloc_map.lock().get(ptr.alloc_id) { |
| Some(GlobalAlloc::Function(..)) => err!(DeallocatedWrongMemoryKind( |
| "function".to_string(), |
| format!("{:?}", kind), |
| )), |
| Some(GlobalAlloc::Static(..)) | |
| Some(GlobalAlloc::Memory(..)) => err!(DeallocatedWrongMemoryKind( |
| "static".to_string(), |
| format!("{:?}", kind), |
| )), |
| None => err!(DoubleFree) |
| } |
| } |
| }; |
| |
| if alloc_kind != kind { |
| return err!(DeallocatedWrongMemoryKind( |
| format!("{:?}", alloc_kind), |
| format!("{:?}", kind), |
| )); |
| } |
| if let Some((size, align)) = size_and_align { |
| if size.bytes() != alloc.bytes.len() as u64 || align != alloc.align { |
| let bytes = Size::from_bytes(alloc.bytes.len() as u64); |
| return err!(IncorrectAllocationInformation(size, |
| bytes, |
| align, |
| alloc.align)); |
| } |
| } |
| |
| // Let the machine take some extra action |
| let size = Size::from_bytes(alloc.bytes.len() as u64); |
| AllocationExtra::memory_deallocated(&mut alloc, ptr, size)?; |
| |
| // Don't forget to remember size and align of this now-dead allocation |
| let old = self.dead_alloc_map.insert( |
| ptr.alloc_id, |
| (Size::from_bytes(alloc.bytes.len() as u64), alloc.align) |
| ); |
| if old.is_some() { |
| bug!("Nothing can be deallocated twice"); |
| } |
| |
| Ok(()) |
| } |
| |
| /// Check if the given scalar is allowed to do a memory access of given `size` |
| /// and `align`. On success, returns `None` for zero-sized accesses (where |
| /// nothing else is left to do) and a `Pointer` to use for the actual access otherwise. |
| /// Crucially, if the input is a `Pointer`, we will test it for liveness |
| /// *even of* the size is 0. |
| /// |
| /// Everyone accessing memory based on a `Scalar` should use this method to get the |
| /// `Pointer` they need. And even if you already have a `Pointer`, call this method |
| /// to make sure it is sufficiently aligned and not dangling. Not doing that may |
| /// cause ICEs. |
| pub fn check_ptr_access( |
| &self, |
| sptr: Scalar<M::PointerTag>, |
| size: Size, |
| align: Align, |
| ) -> InterpResult<'tcx, Option<Pointer<M::PointerTag>>> { |
| fn check_offset_align(offset: u64, align: Align) -> InterpResult<'static> { |
| if offset % align.bytes() == 0 { |
| Ok(()) |
| } else { |
| // The biggest power of two through which `offset` is divisible. |
| let offset_pow2 = 1 << offset.trailing_zeros(); |
| err!(AlignmentCheckFailed { |
| has: Align::from_bytes(offset_pow2).unwrap(), |
| required: align, |
| }) |
| } |
| } |
| |
| // Normalize to a `Pointer` if we definitely need one. |
| let normalized = if size.bytes() == 0 { |
| // Can be an integer, just take what we got. We do NOT `force_bits` here; |
| // if this is already a `Pointer` we want to do the bounds checks! |
| sptr |
| } else { |
| // A "real" access, we must get a pointer. |
| Scalar::Ptr(self.force_ptr(sptr)?) |
| }; |
| Ok(match normalized.to_bits_or_ptr(self.pointer_size(), self) { |
| Ok(bits) => { |
| let bits = bits as u64; // it's ptr-sized |
| assert!(size.bytes() == 0); |
| // Must be non-NULL and aligned. |
| if bits == 0 { |
| return err!(InvalidNullPointerUsage); |
| } |
| check_offset_align(bits, align)?; |
| None |
| } |
| Err(ptr) => { |
| let (allocation_size, alloc_align) = |
| self.get_size_and_align(ptr.alloc_id, AllocCheck::Dereferencable)?; |
| // Test bounds. This also ensures non-NULL. |
| // It is sufficient to check this for the end pointer. The addition |
| // checks for overflow. |
| let end_ptr = ptr.offset(size, self)?; |
| end_ptr.check_in_alloc(allocation_size, CheckInAllocMsg::MemoryAccessTest)?; |
| // Test align. Check this last; if both bounds and alignment are violated |
| // we want the error to be about the bounds. |
| if alloc_align.bytes() < align.bytes() { |
| // The allocation itself is not aligned enough. |
| // FIXME: Alignment check is too strict, depending on the base address that |
| // got picked we might be aligned even if this check fails. |
| // We instead have to fall back to converting to an integer and checking |
| // the "real" alignment. |
| return err!(AlignmentCheckFailed { |
| has: alloc_align, |
| required: align, |
| }); |
| } |
| check_offset_align(ptr.offset.bytes(), align)?; |
| |
| // We can still be zero-sized in this branch, in which case we have to |
| // return `None`. |
| if size.bytes() == 0 { None } else { Some(ptr) } |
| } |
| }) |
| } |
| |
| /// Test if the pointer might be NULL. |
| pub fn ptr_may_be_null( |
| &self, |
| ptr: Pointer<M::PointerTag>, |
| ) -> bool { |
| let (size, _align) = self.get_size_and_align(ptr.alloc_id, AllocCheck::MaybeDead) |
| .expect("alloc info with MaybeDead cannot fail"); |
| ptr.check_in_alloc(size, CheckInAllocMsg::NullPointerTest).is_err() |
| } |
| } |
| |
| /// Allocation accessors |
| impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { |
| /// Helper function to obtain the global (tcx) allocation for a static. |
| /// This attempts to return a reference to an existing allocation if |
| /// one can be found in `tcx`. That, however, is only possible if `tcx` and |
| /// this machine use the same pointer tag, so it is indirected through |
| /// `M::tag_allocation`. |
| /// |
| /// Notice that every static has two `AllocId` that will resolve to the same |
| /// thing here: one maps to `GlobalAlloc::Static`, this is the "lazy" ID, |
| /// and the other one is maps to `GlobalAlloc::Memory`, this is returned by |
| /// `const_eval_raw` and it is the "resolved" ID. |
| /// The resolved ID is never used by the interpreted progrma, it is hidden. |
| /// The `GlobalAlloc::Memory` branch here is still reachable though; when a static |
| /// contains a reference to memory that was created during its evaluation (i.e., not to |
| /// another static), those inner references only exist in "resolved" form. |
| fn get_static_alloc( |
| id: AllocId, |
| tcx: TyCtxtAt<'tcx>, |
| memory: &Memory<'mir, 'tcx, M>, |
| ) -> InterpResult<'tcx, Cow<'tcx, Allocation<M::PointerTag, M::AllocExtra>>> { |
| let alloc = tcx.alloc_map.lock().get(id); |
| let alloc = match alloc { |
| Some(GlobalAlloc::Memory(mem)) => |
| Cow::Borrowed(mem), |
| Some(GlobalAlloc::Function(..)) => |
| return err!(DerefFunctionPointer), |
| None => |
| return err!(DanglingPointerDeref), |
| Some(GlobalAlloc::Static(def_id)) => { |
| // We got a "lazy" static that has not been computed yet. |
| if tcx.is_foreign_item(def_id) { |
| trace!("static_alloc: foreign item {:?}", def_id); |
| M::find_foreign_static(def_id, tcx)? |
| } else { |
| trace!("static_alloc: Need to compute {:?}", def_id); |
| let instance = Instance::mono(tcx.tcx, def_id); |
| let gid = GlobalId { |
| instance, |
| promoted: None, |
| }; |
| // use the raw query here to break validation cycles. Later uses of the static |
| // will call the full query anyway |
| let raw_const = tcx.const_eval_raw(ty::ParamEnv::reveal_all().and(gid)) |
| .map_err(|err| { |
| // no need to report anything, the const_eval call takes care of that |
| // for statics |
| assert!(tcx.is_static(def_id)); |
| match err { |
| ErrorHandled::Reported => InterpError::ReferencedConstant, |
| ErrorHandled::TooGeneric => InterpError::TooGeneric, |
| } |
| })?; |
| // Make sure we use the ID of the resolved memory, not the lazy one! |
| let id = raw_const.alloc_id; |
| let allocation = tcx.alloc_map.lock().unwrap_memory(id); |
| Cow::Borrowed(allocation) |
| } |
| } |
| }; |
| // We got tcx memory. Let the machine figure out whether and how to |
| // turn that into memory with the right pointer tag. |
| Ok(M::tag_allocation( |
| id, // always use the ID we got as input, not the "hidden" one. |
| alloc, |
| M::STATIC_KIND.map(MemoryKind::Machine), |
| memory |
| ).0) |
| } |
| |
| pub fn get( |
| &self, |
| id: AllocId, |
| ) -> InterpResult<'tcx, &Allocation<M::PointerTag, M::AllocExtra>> { |
| // The error type of the inner closure here is somewhat funny. We have two |
| // ways of "erroring": An actual error, or because we got a reference from |
| // `get_static_alloc` that we can actually use directly without inserting anything anywhere. |
| // So the error type is `InterpResult<'tcx, &Allocation<M::PointerTag>>`. |
| let a = self.alloc_map.get_or(id, || { |
| let alloc = Self::get_static_alloc(id, self.tcx, &self).map_err(Err)?; |
| match alloc { |
| Cow::Borrowed(alloc) => { |
| // We got a ref, cheaply return that as an "error" so that the |
| // map does not get mutated. |
| Err(Ok(alloc)) |
| } |
| Cow::Owned(alloc) => { |
| // Need to put it into the map and return a ref to that |
| let kind = M::STATIC_KIND.expect( |
| "I got an owned allocation that I have to copy but the machine does \ |
| not expect that to happen" |
| ); |
| Ok((MemoryKind::Machine(kind), alloc)) |
| } |
| } |
| }); |
| // Now unpack that funny error type |
| match a { |
| Ok(a) => Ok(&a.1), |
| Err(a) => a |
| } |
| } |
| |
| pub fn get_mut( |
| &mut self, |
| id: AllocId, |
| ) -> InterpResult<'tcx, &mut Allocation<M::PointerTag, M::AllocExtra>> { |
| let tcx = self.tcx; |
| let alloc = Self::get_static_alloc(id, tcx, &self); |
| let a = self.alloc_map.get_mut_or(id, || { |
| // Need to make a copy, even if `get_static_alloc` is able |
| // to give us a cheap reference. |
| let alloc = alloc?; |
| if alloc.mutability == Mutability::Immutable { |
| return err!(ModifiedConstantMemory); |
| } |
| match M::STATIC_KIND { |
| Some(kind) => Ok((MemoryKind::Machine(kind), alloc.into_owned())), |
| None => err!(ModifiedStatic), |
| } |
| }); |
| // Unpack the error type manually because type inference doesn't |
| // work otherwise (and we cannot help it because `impl Trait`) |
| match a { |
| Err(e) => Err(e), |
| Ok(a) => { |
| let a = &mut a.1; |
| if a.mutability == Mutability::Immutable { |
| return err!(ModifiedConstantMemory); |
| } |
| Ok(a) |
| } |
| } |
| } |
| |
| /// Obtain the size and alignment of an allocation, even if that allocation has |
| /// been deallocated. |
| /// |
| /// If `liveness` is `AllocCheck::MaybeDead`, this function always returns `Ok`. |
| pub fn get_size_and_align( |
| &self, |
| id: AllocId, |
| liveness: AllocCheck, |
| ) -> InterpResult<'static, (Size, Align)> { |
| if let Ok(alloc) = self.get(id) { |
| return Ok((Size::from_bytes(alloc.bytes.len() as u64), alloc.align)); |
| } |
| // can't do this in the match argument, we may get cycle errors since the lock would get |
| // dropped after the match. |
| let alloc = self.tcx.alloc_map.lock().get(id); |
| // Could also be a fn ptr or extern static |
| match alloc { |
| Some(GlobalAlloc::Function(..)) => { |
| if let AllocCheck::Dereferencable = liveness { |
| // The caller requested no function pointers. |
| err!(DerefFunctionPointer) |
| } else { |
| Ok((Size::ZERO, Align::from_bytes(1).unwrap())) |
| } |
| } |
| // `self.get` would also work, but can cause cycles if a static refers to itself |
| Some(GlobalAlloc::Static(did)) => { |
| // The only way `get` couldn't have worked here is if this is an extern static |
| assert!(self.tcx.is_foreign_item(did)); |
| // Use size and align of the type |
| let ty = self.tcx.type_of(did); |
| let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap(); |
| Ok((layout.size, layout.align.abi)) |
| } |
| _ => { |
| if let Ok(alloc) = self.get(id) { |
| Ok((Size::from_bytes(alloc.bytes.len() as u64), alloc.align)) |
| } |
| else if let AllocCheck::MaybeDead = liveness { |
| // Deallocated pointers are allowed, we should be able to find |
| // them in the map. |
| Ok(*self.dead_alloc_map.get(&id) |
| .expect("deallocated pointers should all be recorded in `dead_alloc_map`")) |
| } else { |
| err!(DanglingPointerDeref) |
| } |
| }, |
| } |
| } |
| |
| pub fn get_fn(&self, ptr: Pointer<M::PointerTag>) -> InterpResult<'tcx, Instance<'tcx>> { |
| if ptr.offset.bytes() != 0 { |
| return err!(InvalidFunctionPointer); |
| } |
| trace!("reading fn ptr: {}", ptr.alloc_id); |
| match self.tcx.alloc_map.lock().get(ptr.alloc_id) { |
| Some(GlobalAlloc::Function(instance)) => Ok(instance), |
| _ => Err(InterpError::ExecuteMemory.into()), |
| } |
| } |
| |
| pub fn mark_immutable(&mut self, id: AllocId) -> InterpResult<'tcx> { |
| self.get_mut(id)?.mutability = Mutability::Immutable; |
| Ok(()) |
| } |
| |
| /// For debugging, print an allocation and all allocations it points to, recursively. |
| pub fn dump_alloc(&self, id: AllocId) { |
| self.dump_allocs(vec![id]); |
| } |
| |
| fn dump_alloc_helper<Tag, Extra>( |
| &self, |
| allocs_seen: &mut FxHashSet<AllocId>, |
| allocs_to_print: &mut VecDeque<AllocId>, |
| mut msg: String, |
| alloc: &Allocation<Tag, Extra>, |
| extra: String, |
| ) { |
| use std::fmt::Write; |
| |
| let prefix_len = msg.len(); |
| let mut relocations = vec![]; |
| |
| for i in 0..(alloc.bytes.len() as u64) { |
| let i = Size::from_bytes(i); |
| if let Some(&(_, target_id)) = alloc.relocations.get(&i) { |
| if allocs_seen.insert(target_id) { |
| allocs_to_print.push_back(target_id); |
| } |
| relocations.push((i, target_id)); |
| } |
| if alloc.undef_mask.is_range_defined(i, i + Size::from_bytes(1)).is_ok() { |
| // this `as usize` is fine, since `i` came from a `usize` |
| write!(msg, "{:02x} ", alloc.bytes[i.bytes() as usize]).unwrap(); |
| } else { |
| msg.push_str("__ "); |
| } |
| } |
| |
| trace!( |
| "{}({} bytes, alignment {}){}", |
| msg, |
| alloc.bytes.len(), |
| alloc.align.bytes(), |
| extra |
| ); |
| |
| if !relocations.is_empty() { |
| msg.clear(); |
| write!(msg, "{:1$}", "", prefix_len).unwrap(); // Print spaces. |
| let mut pos = Size::ZERO; |
| let relocation_width = (self.pointer_size().bytes() - 1) * 3; |
| for (i, target_id) in relocations { |
| // this `as usize` is fine, since we can't print more chars than `usize::MAX` |
| write!(msg, "{:1$}", "", ((i - pos) * 3).bytes() as usize).unwrap(); |
| let target = format!("({})", target_id); |
| // this `as usize` is fine, since we can't print more chars than `usize::MAX` |
| write!(msg, "└{0:─^1$}┘ ", target, relocation_width as usize).unwrap(); |
| pos = i + self.pointer_size(); |
| } |
| trace!("{}", msg); |
| } |
| } |
| |
| /// For debugging, print a list of allocations and all allocations they point to, recursively. |
| pub fn dump_allocs(&self, mut allocs: Vec<AllocId>) { |
| if !log_enabled!(::log::Level::Trace) { |
| return; |
| } |
| allocs.sort(); |
| allocs.dedup(); |
| let mut allocs_to_print = VecDeque::from(allocs); |
| let mut allocs_seen = FxHashSet::default(); |
| |
| while let Some(id) = allocs_to_print.pop_front() { |
| let msg = format!("Alloc {:<5} ", format!("{}:", id)); |
| |
| // normal alloc? |
| match self.alloc_map.get_or(id, || Err(())) { |
| Ok((kind, alloc)) => { |
| let extra = match kind { |
| MemoryKind::Stack => " (stack)".to_owned(), |
| MemoryKind::Vtable => " (vtable)".to_owned(), |
| MemoryKind::Machine(m) => format!(" ({:?})", m), |
| }; |
| self.dump_alloc_helper( |
| &mut allocs_seen, &mut allocs_to_print, |
| msg, alloc, extra |
| ); |
| }, |
| Err(()) => { |
| // static alloc? |
| match self.tcx.alloc_map.lock().get(id) { |
| Some(GlobalAlloc::Memory(alloc)) => { |
| self.dump_alloc_helper( |
| &mut allocs_seen, &mut allocs_to_print, |
| msg, alloc, " (immutable)".to_owned() |
| ); |
| } |
| Some(GlobalAlloc::Function(func)) => { |
| trace!("{} {}", msg, func); |
| } |
| Some(GlobalAlloc::Static(did)) => { |
| trace!("{} {:?}", msg, did); |
| } |
| None => { |
| trace!("{} (deallocated)", msg); |
| } |
| } |
| }, |
| }; |
| |
| } |
| } |
| |
| pub fn leak_report(&self) -> usize { |
| trace!("### LEAK REPORT ###"); |
| let leaks: Vec<_> = self.alloc_map.filter_map_collect(|&id, &(kind, _)| { |
| if kind.may_leak() { None } else { Some(id) } |
| }); |
| let n = leaks.len(); |
| self.dump_allocs(leaks); |
| n |
| } |
| |
| /// This is used by [priroda](https://github.com/oli-obk/priroda) |
| pub fn alloc_map(&self) -> &M::MemoryMap { |
| &self.alloc_map |
| } |
| } |
| |
| /// Reading and writing. |
| impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { |
| /// Performs appropriate bounds checks. |
| pub fn read_bytes( |
| &self, |
| ptr: Scalar<M::PointerTag>, |
| size: Size, |
| ) -> InterpResult<'tcx, &[u8]> { |
| let ptr = match self.check_ptr_access(ptr, size, Align::from_bytes(1).unwrap())? { |
| Some(ptr) => ptr, |
| None => return Ok(&[]), // zero-sized access |
| }; |
| self.get(ptr.alloc_id)?.get_bytes(self, ptr, size) |
| } |
| |
| /// Performs appropriate bounds checks. |
| pub fn copy( |
| &mut self, |
| src: Scalar<M::PointerTag>, |
| src_align: Align, |
| dest: Scalar<M::PointerTag>, |
| dest_align: Align, |
| size: Size, |
| nonoverlapping: bool, |
| ) -> InterpResult<'tcx> { |
| self.copy_repeatedly(src, src_align, dest, dest_align, size, 1, nonoverlapping) |
| } |
| |
| /// Performs appropriate bounds checks. |
| pub fn copy_repeatedly( |
| &mut self, |
| src: Scalar<M::PointerTag>, |
| src_align: Align, |
| dest: Scalar<M::PointerTag>, |
| dest_align: Align, |
| size: Size, |
| length: u64, |
| nonoverlapping: bool, |
| ) -> InterpResult<'tcx> { |
| // We need to check *both* before early-aborting due to the size being 0. |
| let (src, dest) = match (self.check_ptr_access(src, size, src_align)?, |
| self.check_ptr_access(dest, size * length, dest_align)?) |
| { |
| (Some(src), Some(dest)) => (src, dest), |
| // One of the two sizes is 0. |
| _ => return Ok(()), |
| }; |
| |
| // first copy the relocations to a temporary buffer, because |
| // `get_bytes_mut` will clear the relocations, which is correct, |
| // since we don't want to keep any relocations at the target. |
| // (`get_bytes_with_undef_and_ptr` below checks that there are no |
| // relocations overlapping the edges; those would not be handled correctly). |
| let relocations = { |
| let relocations = self.get(src.alloc_id)?.relocations(self, src, size); |
| if relocations.is_empty() { |
| // nothing to copy, ignore even the `length` loop |
| Vec::new() |
| } else { |
| let mut new_relocations = Vec::with_capacity(relocations.len() * (length as usize)); |
| for i in 0..length { |
| new_relocations.extend( |
| relocations |
| .iter() |
| .map(|&(offset, reloc)| { |
| // compute offset for current repetition |
| let dest_offset = dest.offset + (i * size); |
| ( |
| // shift offsets from source allocation to destination allocation |
| offset + dest_offset - src.offset, |
| reloc, |
| ) |
| }) |
| ); |
| } |
| |
| new_relocations |
| } |
| }; |
| |
| let tcx = self.tcx.tcx; |
| |
| // This checks relocation edges on the src. |
| let src_bytes = self.get(src.alloc_id)? |
| .get_bytes_with_undef_and_ptr(&tcx, src, size)? |
| .as_ptr(); |
| let dest_bytes = self.get_mut(dest.alloc_id)? |
| .get_bytes_mut(&tcx, dest, size * length)? |
| .as_mut_ptr(); |
| |
| // SAFE: The above indexing would have panicked if there weren't at least `size` bytes |
| // behind `src` and `dest`. Also, we use the overlapping-safe `ptr::copy` if `src` and |
| // `dest` could possibly overlap. |
| // The pointers above remain valid even if the `HashMap` table is moved around because they |
| // point into the `Vec` storing the bytes. |
| unsafe { |
| assert_eq!(size.bytes() as usize as u64, size.bytes()); |
| if src.alloc_id == dest.alloc_id { |
| if nonoverlapping { |
| if (src.offset <= dest.offset && src.offset + size > dest.offset) || |
| (dest.offset <= src.offset && dest.offset + size > src.offset) |
| { |
| return err!(Intrinsic( |
| "copy_nonoverlapping called on overlapping ranges".to_string(), |
| )); |
| } |
| } |
| |
| for i in 0..length { |
| ptr::copy(src_bytes, |
| dest_bytes.offset((size.bytes() * i) as isize), |
| size.bytes() as usize); |
| } |
| } else { |
| for i in 0..length { |
| ptr::copy_nonoverlapping(src_bytes, |
| dest_bytes.offset((size.bytes() * i) as isize), |
| size.bytes() as usize); |
| } |
| } |
| } |
| |
| // copy definedness to the destination |
| self.copy_undef_mask(src, dest, size, length)?; |
| // copy the relocations to the destination |
| self.get_mut(dest.alloc_id)?.relocations.insert_presorted(relocations); |
| |
| Ok(()) |
| } |
| } |
| |
| /// Undefined bytes |
| impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> { |
| // FIXME: Add a fast version for the common, nonoverlapping case |
| fn copy_undef_mask( |
| &mut self, |
| src: Pointer<M::PointerTag>, |
| dest: Pointer<M::PointerTag>, |
| size: Size, |
| repeat: u64, |
| ) -> InterpResult<'tcx> { |
| // The bits have to be saved locally before writing to dest in case src and dest overlap. |
| assert_eq!(size.bytes() as usize as u64, size.bytes()); |
| |
| let undef_mask = &self.get(src.alloc_id)?.undef_mask; |
| |
| // Since we are copying `size` bytes from `src` to `dest + i * size` (`for i in 0..repeat`), |
| // a naive undef mask copying algorithm would repeatedly have to read the undef mask from |
| // the source and write it to the destination. Even if we optimized the memory accesses, |
| // we'd be doing all of this `repeat` times. |
| // Therefor we precompute a compressed version of the undef mask of the source value and |
| // then write it back `repeat` times without computing any more information from the source. |
| |
| // a precomputed cache for ranges of defined/undefined bits |
| // 0000010010001110 will become |
| // [5, 1, 2, 1, 3, 3, 1] |
| // where each element toggles the state |
| let mut ranges = smallvec::SmallVec::<[u64; 1]>::new(); |
| let first = undef_mask.get(src.offset); |
| let mut cur_len = 1; |
| let mut cur = first; |
| for i in 1..size.bytes() { |
| // FIXME: optimize to bitshift the current undef block's bits and read the top bit |
| if undef_mask.get(src.offset + Size::from_bytes(i)) == cur { |
| cur_len += 1; |
| } else { |
| ranges.push(cur_len); |
| cur_len = 1; |
| cur = !cur; |
| } |
| } |
| |
| // now fill in all the data |
| let dest_allocation = self.get_mut(dest.alloc_id)?; |
| // an optimization where we can just overwrite an entire range of definedness bits if |
| // they are going to be uniformly `1` or `0`. |
| if ranges.is_empty() { |
| dest_allocation.undef_mask.set_range_inbounds( |
| dest.offset, |
| dest.offset + size * repeat, |
| first, |
| ); |
| return Ok(()) |
| } |
| |
| // remember to fill in the trailing bits |
| ranges.push(cur_len); |
| |
| for mut j in 0..repeat { |
| j *= size.bytes(); |
| j += dest.offset.bytes(); |
| let mut cur = first; |
| for range in &ranges { |
| let old_j = j; |
| j += range; |
| dest_allocation.undef_mask.set_range_inbounds( |
| Size::from_bytes(old_j), |
| Size::from_bytes(j), |
| cur, |
| ); |
| cur = !cur; |
| } |
| } |
| Ok(()) |
| } |
| |
| pub fn force_ptr( |
| &self, |
| scalar: Scalar<M::PointerTag>, |
| ) -> InterpResult<'tcx, Pointer<M::PointerTag>> { |
| match scalar { |
| Scalar::Ptr(ptr) => Ok(ptr), |
| _ => M::int_to_ptr(scalar.to_usize(self)?, self) |
| } |
| } |
| |
| pub fn force_bits( |
| &self, |
| scalar: Scalar<M::PointerTag>, |
| size: Size |
| ) -> InterpResult<'tcx, u128> { |
| match scalar.to_bits_or_ptr(size, self) { |
| Ok(bits) => Ok(bits), |
| Err(ptr) => Ok(M::ptr_to_int(ptr, self)? as u128) |
| } |
| } |
| } |
