| // Copyright 2018 The Rust Project Developers. See the COPYRIGHT |
| // file at the top-level directory of this distribution and at |
| // http://rust-lang.org/COPYRIGHT. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| |
| //! 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}; |
| pub use rustc::mir::interpret::{truncate, write_target_uint, read_target_uint}; |
| use rustc_data_structures::fx::{FxHashSet, FxHashMap}; |
| |
| use syntax::ast::Mutability; |
| |
| use super::{ |
| Pointer, AllocId, Allocation, GlobalId, AllocationExtra, |
| EvalResult, Scalar, EvalErrorKind, AllocType, PointerArithmetic, |
| Machine, AllocMap, MayLeak, ErrorHandled, InboundsCheck, |
| }; |
| |
| #[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() |
| } |
| } |
| } |
| |
| // `Memory` has to depend on the `Machine` because some of its operations |
| // (e.g. `get`) call a `Machine` hook. |
| pub struct Memory<'a, 'mir, 'tcx: 'a + 'mir, M: Machine<'a, '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. |
| 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. |
| 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<'a, 'tcx, 'tcx>, |
| } |
| |
| impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> HasDataLayout |
| for Memory<'a, '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<'a, 'mir, 'tcx, M> |
| Clone |
| for |
| Memory<'a, 'mir, 'tcx, M> |
| where |
| M: Machine<'a, '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<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> { |
| pub fn new(tcx: TyCtxtAt<'a, 'tcx, 'tcx>) -> Self { |
| Memory { |
| alloc_map: M::MemoryMap::default(), |
| dead_alloc_map: FxHashMap::default(), |
| extra: M::MemoryExtra::default(), |
| tcx, |
| } |
| } |
| |
| pub fn create_fn_alloc(&mut self, instance: Instance<'tcx>) -> Pointer { |
| Pointer::from(self.tcx.alloc_map.lock().create_fn_alloc(instance)) |
| } |
| |
| pub fn allocate_static_bytes(&mut self, bytes: &[u8]) -> Pointer { |
| Pointer::from(self.tcx.allocate_bytes(bytes)) |
| } |
| |
| pub fn allocate_with( |
| &mut self, |
| alloc: Allocation<M::PointerTag, M::AllocExtra>, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> EvalResult<'tcx, AllocId> { |
| let id = self.tcx.alloc_map.lock().reserve(); |
| self.alloc_map.insert(id, (kind, alloc)); |
| Ok(id) |
| } |
| |
| pub fn allocate( |
| &mut self, |
| size: Size, |
| align: Align, |
| kind: MemoryKind<M::MemoryKinds>, |
| ) -> EvalResult<'tcx, Pointer> { |
| let extra = AllocationExtra::memory_allocated(size, &self.extra); |
| Ok(Pointer::from(self.allocate_with(Allocation::undef(size, align, extra), kind)?)) |
| } |
| |
| 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>, |
| ) -> EvalResult<'tcx, Pointer> { |
| 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.with_default_tag().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>) -> EvalResult<'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>, |
| ) -> EvalResult<'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(AllocType::Function(..)) => err!(DeallocatedWrongMemoryKind( |
| "function".to_string(), |
| format!("{:?}", kind), |
| )), |
| Some(AllocType::Static(..)) | |
| Some(AllocType::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 that the pointer is aligned AND non-NULL. This supports ZSTs in two ways: |
| /// You can pass a scalar, and a `Pointer` does not have to actually still be allocated. |
| pub fn check_align( |
| &self, |
| ptr: Scalar<M::PointerTag>, |
| required_align: Align |
| ) -> EvalResult<'tcx> { |
| // Check non-NULL/Undef, extract offset |
| let (offset, alloc_align) = match ptr { |
| Scalar::Ptr(ptr) => { |
| // check this is not NULL -- which we can ensure only if this is in-bounds |
| // of some (potentially dead) allocation. |
| let align = self.check_bounds_ptr_maybe_dead(ptr)?; |
| (ptr.offset.bytes(), align) |
| } |
| Scalar::Bits { bits, size } => { |
| assert_eq!(size as u64, self.pointer_size().bytes()); |
| assert!(bits < (1u128 << self.pointer_size().bits())); |
| // check this is not NULL |
| if bits == 0 { |
| return err!(InvalidNullPointerUsage); |
| } |
| // the "base address" is 0 and hence always aligned |
| (bits as u64, required_align) |
| } |
| }; |
| // Check alignment |
| if alloc_align.bytes() < required_align.bytes() { |
| return err!(AlignmentCheckFailed { |
| has: alloc_align, |
| required: required_align, |
| }); |
| } |
| if offset % required_align.bytes() == 0 { |
| Ok(()) |
| } else { |
| let has = offset % required_align.bytes(); |
| err!(AlignmentCheckFailed { |
| has: Align::from_bytes(has).unwrap(), |
| required: required_align, |
| }) |
| } |
| } |
| |
| /// Check if the pointer is "in-bounds". Notice that a pointer pointing at the end |
| /// of an allocation (i.e., at the first *inaccessible* location) *is* considered |
| /// in-bounds! This follows C's/LLVM's rules. |
| /// This function also works for deallocated allocations. |
| /// Use `.get(ptr.alloc_id)?.check_bounds_ptr(ptr)` if you want to force the allocation |
| /// to still be live. |
| /// If you want to check bounds before doing a memory access, better first obtain |
| /// an `Allocation` and call `check_bounds`. |
| pub fn check_bounds_ptr_maybe_dead( |
| &self, |
| ptr: Pointer<M::PointerTag>, |
| ) -> EvalResult<'tcx, Align> { |
| let (allocation_size, align) = self.get_size_and_align(ptr.alloc_id); |
| ptr.check_in_alloc(allocation_size, InboundsCheck::MaybeDead)?; |
| Ok(align) |
| } |
| } |
| |
| /// Allocation accessors |
| impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, '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::static_with_default_tag`. |
| fn get_static_alloc( |
| id: AllocId, |
| tcx: TyCtxtAt<'a, 'tcx, 'tcx>, |
| memory_extra: &M::MemoryExtra, |
| ) -> EvalResult<'tcx, Cow<'tcx, Allocation<M::PointerTag, M::AllocExtra>>> { |
| let alloc = tcx.alloc_map.lock().get(id); |
| let def_id = match alloc { |
| Some(AllocType::Memory(mem)) => { |
| // We got tcx memory. Let the machine figure out whether and how to |
| // turn that into memory with the right pointer tag. |
| return Ok(M::adjust_static_allocation(mem, memory_extra)) |
| } |
| Some(AllocType::Function(..)) => { |
| return err!(DerefFunctionPointer) |
| } |
| Some(AllocType::Static(did)) => { |
| did |
| } |
| None => |
| return err!(DanglingPointerDeref), |
| }; |
| // We got a "lazy" static that has not been computed yet, do some work |
| trace!("static_alloc: Need to compute {:?}", def_id); |
| if tcx.is_foreign_item(def_id) { |
| return M::find_foreign_static(def_id, tcx, memory_extra); |
| } |
| 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 |
| 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).is_some()); |
| match err { |
| ErrorHandled::Reported => EvalErrorKind::ReferencedConstant.into(), |
| ErrorHandled::TooGeneric => EvalErrorKind::TooGeneric.into(), |
| } |
| }).map(|raw_const| { |
| let allocation = tcx.alloc_map.lock().unwrap_memory(raw_const.alloc_id); |
| // We got tcx memory. Let the machine figure out whether and how to |
| // turn that into memory with the right pointer tag. |
| M::adjust_static_allocation(allocation, memory_extra) |
| }) |
| } |
| |
| pub fn get(&self, id: AllocId) -> EvalResult<'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 `EvalResult<'tcx, &Allocation<M::PointerTag>>`. |
| let a = self.alloc_map.get_or(id, || { |
| let alloc = Self::get_static_alloc(id, self.tcx, &self.extra).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, |
| ) -> EvalResult<'tcx, &mut Allocation<M::PointerTag, M::AllocExtra>> { |
| let tcx = self.tcx; |
| let memory_extra = &self.extra; |
| 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 = Self::get_static_alloc(id, tcx, memory_extra)?; |
| 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) |
| } |
| } |
| } |
| |
| pub fn get_size_and_align(&self, id: AllocId) -> (Size, Align) { |
| if let Ok(alloc) = self.get(id) { |
| return (Size::from_bytes(alloc.bytes.len() as u64), alloc.align); |
| } |
| // Could also be a fn ptr or extern static |
| match self.tcx.alloc_map.lock().get(id) { |
| Some(AllocType::Function(..)) => (Size::ZERO, Align::from_bytes(1).unwrap()), |
| Some(AllocType::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(); |
| (layout.size, layout.align.abi) |
| } |
| _ => { |
| // Must be a deallocated pointer |
| *self.dead_alloc_map.get(&id).expect( |
| "allocation missing in dead_alloc_map" |
| ) |
| } |
| } |
| } |
| |
| pub fn get_fn(&self, ptr: Pointer<M::PointerTag>) -> EvalResult<'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(AllocType::Function(instance)) => Ok(instance), |
| _ => Err(EvalErrorKind::ExecuteMemory.into()), |
| } |
| } |
| |
| pub fn mark_immutable(&mut self, id: AllocId) -> EvalResult<'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(AllocType::Memory(alloc)) => { |
| self.dump_alloc_helper( |
| &mut allocs_seen, &mut allocs_to_print, |
| msg, alloc, " (immutable)".to_owned() |
| ); |
| } |
| Some(AllocType::Function(func)) => { |
| trace!("{} {}", msg, func); |
| } |
| Some(AllocType::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 |
| } |
| } |
| |
| /// Byte Accessors |
| impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> { |
| pub fn read_bytes( |
| &self, |
| ptr: Scalar<M::PointerTag>, |
| size: Size, |
| ) -> EvalResult<'tcx, &[u8]> { |
| if size.bytes() == 0 { |
| Ok(&[]) |
| } else { |
| let ptr = ptr.to_ptr()?; |
| self.get(ptr.alloc_id)?.get_bytes(self, ptr, size) |
| } |
| } |
| } |
| |
| /// Interning (for CTFE) |
| impl<'a, 'mir, 'tcx, M> Memory<'a, 'mir, 'tcx, M> |
| where |
| M: Machine<'a, 'mir, 'tcx, PointerTag=(), AllocExtra=(), MemoryExtra=()>, |
| // FIXME: Working around https://github.com/rust-lang/rust/issues/24159 |
| M::MemoryMap: AllocMap<AllocId, (MemoryKind<M::MemoryKinds>, Allocation)>, |
| { |
| /// mark an allocation as static and initialized, either mutable or not |
| pub fn intern_static( |
| &mut self, |
| alloc_id: AllocId, |
| mutability: Mutability, |
| ) -> EvalResult<'tcx> { |
| trace!( |
| "mark_static_initialized {:?}, mutability: {:?}", |
| alloc_id, |
| mutability |
| ); |
| // remove allocation |
| let (kind, mut alloc) = self.alloc_map.remove(&alloc_id).unwrap(); |
| match kind { |
| MemoryKind::Machine(_) => bug!("Static cannot refer to machine memory"), |
| MemoryKind::Stack | MemoryKind::Vtable => {}, |
| } |
| // ensure llvm knows not to put this into immutable memory |
| alloc.mutability = mutability; |
| let alloc = self.tcx.intern_const_alloc(alloc); |
| self.tcx.alloc_map.lock().set_id_memory(alloc_id, alloc); |
| // recurse into inner allocations |
| for &(_, alloc) in alloc.relocations.values() { |
| // FIXME: Reusing the mutability here is likely incorrect. It is originally |
| // determined via `is_freeze`, and data is considered frozen if there is no |
| // `UnsafeCell` *immediately* in that data -- however, this search stops |
| // at references. So whenever we follow a reference, we should likely |
| // assume immutability -- and we should make sure that the compiler |
| // does not permit code that would break this! |
| if self.alloc_map.contains_key(&alloc) { |
| // Not yet interned, so proceed recursively |
| self.intern_static(alloc, mutability)?; |
| } else if self.dead_alloc_map.contains_key(&alloc) { |
| // dangling pointer |
| return err!(ValidationFailure( |
| "encountered dangling pointer in final constant".into(), |
| )) |
| } |
| } |
| Ok(()) |
| } |
| } |
| |
| /// Reading and writing |
| impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> { |
| pub fn copy( |
| &mut self, |
| src: Scalar<M::PointerTag>, |
| src_align: Align, |
| dest: Scalar<M::PointerTag>, |
| dest_align: Align, |
| size: Size, |
| nonoverlapping: bool, |
| ) -> EvalResult<'tcx> { |
| self.copy_repeatedly(src, src_align, dest, dest_align, size, 1, nonoverlapping) |
| } |
| |
| 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, |
| ) -> EvalResult<'tcx> { |
| self.check_align(src, src_align)?; |
| self.check_align(dest, dest_align)?; |
| if size.bytes() == 0 { |
| // Nothing to do for ZST, other than checking alignment and |
| // non-NULLness which already happened. |
| return Ok(()); |
| } |
| let src = src.to_ptr()?; |
| let dest = dest.to_ptr()?; |
| |
| // 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); |
| 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)| { |
| (offset + dest.offset - src.offset + (i * size * relocations.len() as u64), |
| 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<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, '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, |
| ) -> EvalResult<'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.clone(); |
| let dest_allocation = self.get_mut(dest.alloc_id)?; |
| |
| for i in 0..size.bytes() { |
| let defined = undef_mask.get(src.offset + Size::from_bytes(i)); |
| |
| for j in 0..repeat { |
| dest_allocation.undef_mask.set( |
| dest.offset + Size::from_bytes(i + (size.bytes() * j)), |
| defined |
| ); |
| } |
| } |
| |
| Ok(()) |
| } |
| } |