1236 lines
50 KiB
Rust
1236 lines
50 KiB
Rust
//! The memory subsystem.
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//!
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//! Generally, we use `Pointer` to denote memory addresses. However, some operations
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//! have a "size"-like parameter, and they take `Scalar` for the address because
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//! if the size is 0, then the pointer can also be a (properly aligned, non-null)
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//! integer. It is crucial that these operations call `check_align` *before*
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//! short-circuiting the empty case!
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use std::assert_matches::assert_matches;
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use std::borrow::Cow;
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use std::collections::VecDeque;
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use std::fmt;
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use std::ptr;
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use rustc_ast::Mutability;
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use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_middle::mir::display_allocation;
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use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TyCtxt};
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use rustc_target::abi::{Align, HasDataLayout, Size};
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use crate::const_eval::CheckAlignment;
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use super::{
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alloc_range, AllocId, AllocMap, AllocRange, Allocation, CheckInAllocMsg, GlobalAlloc, InterpCx,
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InterpResult, Machine, MayLeak, Pointer, PointerArithmetic, Provenance, Scalar,
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};
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#[derive(Debug, PartialEq, Copy, Clone)]
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pub enum MemoryKind<T> {
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/// Stack memory. Error if deallocated except during a stack pop.
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Stack,
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/// Memory allocated by `caller_location` intrinsic. Error if ever deallocated.
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CallerLocation,
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/// Additional memory kinds a machine wishes to distinguish from the builtin ones.
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Machine(T),
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}
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impl<T: MayLeak> MayLeak for MemoryKind<T> {
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#[inline]
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fn may_leak(self) -> bool {
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match self {
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MemoryKind::Stack => false,
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MemoryKind::CallerLocation => true,
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MemoryKind::Machine(k) => k.may_leak(),
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}
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}
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}
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impl<T: fmt::Display> fmt::Display for MemoryKind<T> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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match self {
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MemoryKind::Stack => write!(f, "stack variable"),
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MemoryKind::CallerLocation => write!(f, "caller location"),
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MemoryKind::Machine(m) => write!(f, "{}", m),
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}
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}
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}
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/// The return value of `get_alloc_info` indicates the "kind" of the allocation.
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pub enum AllocKind {
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/// A regular live data allocation.
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LiveData,
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/// A function allocation (that fn ptrs point to).
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Function,
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/// A (symbolic) vtable allocation.
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VTable,
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/// A dead allocation.
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Dead,
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}
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/// The value of a function pointer.
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#[derive(Debug, Copy, Clone)]
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pub enum FnVal<'tcx, Other> {
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Instance(Instance<'tcx>),
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Other(Other),
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}
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impl<'tcx, Other> FnVal<'tcx, Other> {
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pub fn as_instance(self) -> InterpResult<'tcx, Instance<'tcx>> {
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match self {
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FnVal::Instance(instance) => Ok(instance),
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FnVal::Other(_) => {
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throw_unsup_format!("'foreign' function pointers are not supported in this context")
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}
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}
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}
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}
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// `Memory` has to depend on the `Machine` because some of its operations
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// (e.g., `get`) call a `Machine` hook.
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pub struct Memory<'mir, 'tcx, M: Machine<'mir, 'tcx>> {
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/// Allocations local to this instance of the miri engine. The kind
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/// helps ensure that the same mechanism is used for allocation and
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/// deallocation. When an allocation is not found here, it is a
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/// global and looked up in the `tcx` for read access. Some machines may
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/// have to mutate this map even on a read-only access to a global (because
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/// they do pointer provenance tracking and the allocations in `tcx` have
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/// the wrong type), so we let the machine override this type.
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/// Either way, if the machine allows writing to a global, doing so will
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/// create a copy of the global allocation here.
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// FIXME: this should not be public, but interning currently needs access to it
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pub(super) alloc_map: M::MemoryMap,
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/// Map for "extra" function pointers.
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extra_fn_ptr_map: FxHashMap<AllocId, M::ExtraFnVal>,
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/// To be able to compare pointers with null, and to check alignment for accesses
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/// to ZSTs (where pointers may dangle), we keep track of the size even for allocations
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/// that do not exist any more.
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// FIXME: this should not be public, but interning currently needs access to it
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pub(super) dead_alloc_map: FxHashMap<AllocId, (Size, Align)>,
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}
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/// A reference to some allocation that was already bounds-checked for the given region
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/// and had the on-access machine hooks run.
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#[derive(Copy, Clone)]
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pub struct AllocRef<'a, 'tcx, Prov: Provenance, Extra> {
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alloc: &'a Allocation<Prov, Extra>,
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range: AllocRange,
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tcx: TyCtxt<'tcx>,
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alloc_id: AllocId,
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}
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/// A reference to some allocation that was already bounds-checked for the given region
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/// and had the on-access machine hooks run.
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pub struct AllocRefMut<'a, 'tcx, Prov: Provenance, Extra> {
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alloc: &'a mut Allocation<Prov, Extra>,
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range: AllocRange,
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tcx: TyCtxt<'tcx>,
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alloc_id: AllocId,
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}
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impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'mir, 'tcx, M> {
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pub fn new() -> Self {
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Memory {
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alloc_map: M::MemoryMap::default(),
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extra_fn_ptr_map: FxHashMap::default(),
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dead_alloc_map: FxHashMap::default(),
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}
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}
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/// This is used by [priroda](https://github.com/oli-obk/priroda)
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pub fn alloc_map(&self) -> &M::MemoryMap {
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&self.alloc_map
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}
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}
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impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
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/// Call this to turn untagged "global" pointers (obtained via `tcx`) into
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/// the machine pointer to the allocation. Must never be used
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/// for any other pointers, nor for TLS statics.
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///
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/// Using the resulting pointer represents a *direct* access to that memory
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/// (e.g. by directly using a `static`),
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/// as opposed to access through a pointer that was created by the program.
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///
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/// This function can fail only if `ptr` points to an `extern static`.
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#[inline]
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pub fn global_base_pointer(
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&self,
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ptr: Pointer<AllocId>,
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) -> InterpResult<'tcx, Pointer<M::Provenance>> {
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let alloc_id = ptr.provenance;
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// We need to handle `extern static`.
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match self.tcx.try_get_global_alloc(alloc_id) {
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Some(GlobalAlloc::Static(def_id)) if self.tcx.is_thread_local_static(def_id) => {
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bug!("global memory cannot point to thread-local static")
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}
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Some(GlobalAlloc::Static(def_id)) if self.tcx.is_foreign_item(def_id) => {
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return M::extern_static_base_pointer(self, def_id);
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}
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_ => {}
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}
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// And we need to get the provenance.
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Ok(M::adjust_alloc_base_pointer(self, ptr))
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}
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pub fn create_fn_alloc_ptr(
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&mut self,
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fn_val: FnVal<'tcx, M::ExtraFnVal>,
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) -> Pointer<M::Provenance> {
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let id = match fn_val {
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FnVal::Instance(instance) => self.tcx.create_fn_alloc(instance),
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FnVal::Other(extra) => {
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// FIXME(RalfJung): Should we have a cache here?
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let id = self.tcx.reserve_alloc_id();
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let old = self.memory.extra_fn_ptr_map.insert(id, extra);
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assert!(old.is_none());
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id
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}
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};
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// Functions are global allocations, so make sure we get the right base pointer.
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// We know this is not an `extern static` so this cannot fail.
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self.global_base_pointer(Pointer::from(id)).unwrap()
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}
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pub fn allocate_ptr(
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&mut self,
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size: Size,
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align: Align,
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kind: MemoryKind<M::MemoryKind>,
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) -> InterpResult<'tcx, Pointer<M::Provenance>> {
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let alloc = Allocation::uninit(size, align, M::PANIC_ON_ALLOC_FAIL)?;
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// We can `unwrap` since `alloc` contains no pointers.
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Ok(self.allocate_raw_ptr(alloc, kind).unwrap())
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}
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pub fn allocate_bytes_ptr(
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&mut self,
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bytes: &[u8],
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align: Align,
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kind: MemoryKind<M::MemoryKind>,
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mutability: Mutability,
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) -> Pointer<M::Provenance> {
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let alloc = Allocation::from_bytes(bytes, align, mutability);
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// We can `unwrap` since `alloc` contains no pointers.
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self.allocate_raw_ptr(alloc, kind).unwrap()
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}
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/// This can fail only of `alloc` contains provenance.
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pub fn allocate_raw_ptr(
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&mut self,
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alloc: Allocation,
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kind: MemoryKind<M::MemoryKind>,
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) -> InterpResult<'tcx, Pointer<M::Provenance>> {
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let id = self.tcx.reserve_alloc_id();
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debug_assert_ne!(
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Some(kind),
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M::GLOBAL_KIND.map(MemoryKind::Machine),
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"dynamically allocating global memory"
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);
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let alloc = M::adjust_allocation(self, id, Cow::Owned(alloc), Some(kind))?;
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self.memory.alloc_map.insert(id, (kind, alloc.into_owned()));
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Ok(M::adjust_alloc_base_pointer(self, Pointer::from(id)))
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}
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pub fn reallocate_ptr(
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&mut self,
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ptr: Pointer<Option<M::Provenance>>,
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old_size_and_align: Option<(Size, Align)>,
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new_size: Size,
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new_align: Align,
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kind: MemoryKind<M::MemoryKind>,
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) -> InterpResult<'tcx, Pointer<M::Provenance>> {
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let (alloc_id, offset, _prov) = self.ptr_get_alloc_id(ptr)?;
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if offset.bytes() != 0 {
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throw_ub_format!(
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"reallocating {:?} which does not point to the beginning of an object",
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ptr
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);
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}
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// For simplicities' sake, we implement reallocate as "alloc, copy, dealloc".
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// This happens so rarely, the perf advantage is outweighed by the maintenance cost.
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let new_ptr = self.allocate_ptr(new_size, new_align, kind)?;
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let old_size = match old_size_and_align {
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Some((size, _align)) => size,
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None => self.get_alloc_raw(alloc_id)?.size(),
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};
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// This will also call the access hooks.
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self.mem_copy(
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ptr,
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Align::ONE,
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new_ptr.into(),
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Align::ONE,
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old_size.min(new_size),
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/*nonoverlapping*/ true,
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)?;
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self.deallocate_ptr(ptr, old_size_and_align, kind)?;
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Ok(new_ptr)
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}
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#[instrument(skip(self), level = "debug")]
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pub fn deallocate_ptr(
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&mut self,
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ptr: Pointer<Option<M::Provenance>>,
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old_size_and_align: Option<(Size, Align)>,
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kind: MemoryKind<M::MemoryKind>,
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) -> InterpResult<'tcx> {
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let (alloc_id, offset, prov) = self.ptr_get_alloc_id(ptr)?;
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trace!("deallocating: {alloc_id:?}");
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if offset.bytes() != 0 {
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throw_ub_format!(
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"deallocating {:?} which does not point to the beginning of an object",
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ptr
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);
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}
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let Some((alloc_kind, mut alloc)) = self.memory.alloc_map.remove(&alloc_id) else {
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// Deallocating global memory -- always an error
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return Err(match self.tcx.try_get_global_alloc(alloc_id) {
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Some(GlobalAlloc::Function(..)) => {
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err_ub_format!("deallocating {alloc_id:?}, which is a function")
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}
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Some(GlobalAlloc::VTable(..)) => {
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err_ub_format!("deallocating {alloc_id:?}, which is a vtable")
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}
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Some(GlobalAlloc::Static(..) | GlobalAlloc::Memory(..)) => {
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err_ub_format!("deallocating {alloc_id:?}, which is static memory")
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}
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None => err_ub!(PointerUseAfterFree(alloc_id)),
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}
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.into());
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};
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if alloc.mutability == Mutability::Not {
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throw_ub_format!("deallocating immutable allocation {alloc_id:?}");
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}
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if alloc_kind != kind {
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throw_ub_format!(
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"deallocating {alloc_id:?}, which is {alloc_kind} memory, using {kind} deallocation operation"
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);
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}
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if let Some((size, align)) = old_size_and_align {
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if size != alloc.size() || align != alloc.align {
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throw_ub_format!(
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"incorrect layout on deallocation: {alloc_id:?} has size {} and alignment {}, but gave size {} and alignment {}",
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alloc.size().bytes(),
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alloc.align.bytes(),
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size.bytes(),
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align.bytes(),
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)
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}
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}
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// Let the machine take some extra action
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let size = alloc.size();
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M::before_memory_deallocation(
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*self.tcx,
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&mut self.machine,
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&mut alloc.extra,
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(alloc_id, prov),
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alloc_range(Size::ZERO, size),
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)?;
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// Don't forget to remember size and align of this now-dead allocation
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let old = self.memory.dead_alloc_map.insert(alloc_id, (size, alloc.align));
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if old.is_some() {
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bug!("Nothing can be deallocated twice");
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}
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Ok(())
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}
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/// Internal helper function to determine the allocation and offset of a pointer (if any).
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#[inline(always)]
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fn get_ptr_access(
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&self,
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ptr: Pointer<Option<M::Provenance>>,
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size: Size,
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align: Align,
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) -> InterpResult<'tcx, Option<(AllocId, Size, M::ProvenanceExtra)>> {
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self.check_and_deref_ptr(
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ptr,
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size,
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align,
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M::enforce_alignment(self),
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CheckInAllocMsg::MemoryAccessTest,
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|alloc_id, offset, prov| {
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let (size, align) = self.get_live_alloc_size_and_align(alloc_id)?;
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Ok((size, align, (alloc_id, offset, prov)))
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},
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)
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}
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|
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/// Check if the given pointer points to live memory of given `size` and `align`
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/// (ignoring `M::enforce_alignment`). The caller can control the error message for the
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/// out-of-bounds case.
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#[inline(always)]
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pub fn check_ptr_access_align(
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&self,
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ptr: Pointer<Option<M::Provenance>>,
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size: Size,
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align: Align,
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msg: CheckInAllocMsg,
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) -> InterpResult<'tcx> {
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self.check_and_deref_ptr(
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ptr,
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size,
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align,
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CheckAlignment::Error,
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msg,
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|alloc_id, _, _| {
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let (size, align) = self.get_live_alloc_size_and_align(alloc_id)?;
|
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Ok((size, align, ()))
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},
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)?;
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Ok(())
|
|
}
|
|
|
|
/// Low-level helper function to check if a ptr is in-bounds and potentially return a reference
|
|
/// to the allocation it points to. Supports both shared and mutable references, as the actual
|
|
/// checking is offloaded to a helper closure. `align` defines whether and which alignment check
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/// is done. Returns `None` for size 0, and otherwise `Some` of what `alloc_size` returned.
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fn check_and_deref_ptr<T>(
|
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&self,
|
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ptr: Pointer<Option<M::Provenance>>,
|
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size: Size,
|
|
align: Align,
|
|
check: CheckAlignment,
|
|
msg: CheckInAllocMsg,
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alloc_size: impl FnOnce(
|
|
AllocId,
|
|
Size,
|
|
M::ProvenanceExtra,
|
|
) -> InterpResult<'tcx, (Size, Align, T)>,
|
|
) -> InterpResult<'tcx, Option<T>> {
|
|
Ok(match self.ptr_try_get_alloc_id(ptr) {
|
|
Err(addr) => {
|
|
// We couldn't get a proper allocation. This is only okay if the access size is 0,
|
|
// and the address is not null.
|
|
if size.bytes() > 0 || addr == 0 {
|
|
throw_ub!(DanglingIntPointer(addr, msg));
|
|
}
|
|
// Must be aligned.
|
|
if check.should_check() {
|
|
self.check_offset_align(addr, align, check)?;
|
|
}
|
|
None
|
|
}
|
|
Ok((alloc_id, offset, prov)) => {
|
|
let (alloc_size, alloc_align, ret_val) = alloc_size(alloc_id, offset, prov)?;
|
|
// Test bounds. This also ensures non-null.
|
|
// It is sufficient to check this for the end pointer. Also check for overflow!
|
|
if offset.checked_add(size, &self.tcx).map_or(true, |end| end > alloc_size) {
|
|
throw_ub!(PointerOutOfBounds {
|
|
alloc_id,
|
|
alloc_size,
|
|
ptr_offset: self.machine_usize_to_isize(offset.bytes()),
|
|
ptr_size: size,
|
|
msg,
|
|
})
|
|
}
|
|
// Ensure we never consider the null pointer dereferenceable.
|
|
if M::Provenance::OFFSET_IS_ADDR {
|
|
assert_ne!(ptr.addr(), Size::ZERO);
|
|
}
|
|
// Test align. Check this last; if both bounds and alignment are violated
|
|
// we want the error to be about the bounds.
|
|
if check.should_check() {
|
|
if M::use_addr_for_alignment_check(self) {
|
|
// `use_addr_for_alignment_check` can only be true if `OFFSET_IS_ADDR` is true.
|
|
self.check_offset_align(ptr.addr().bytes(), align, check)?;
|
|
} else {
|
|
// Check allocation alignment and offset alignment.
|
|
if alloc_align.bytes() < align.bytes() {
|
|
M::alignment_check_failed(self, alloc_align, align, check)?;
|
|
}
|
|
self.check_offset_align(offset.bytes(), align, check)?;
|
|
}
|
|
}
|
|
|
|
// We can still be zero-sized in this branch, in which case we have to
|
|
// return `None`.
|
|
if size.bytes() == 0 { None } else { Some(ret_val) }
|
|
}
|
|
})
|
|
}
|
|
|
|
fn check_offset_align(
|
|
&self,
|
|
offset: u64,
|
|
align: Align,
|
|
check: CheckAlignment,
|
|
) -> InterpResult<'tcx> {
|
|
if offset % align.bytes() == 0 {
|
|
Ok(())
|
|
} else {
|
|
// The biggest power of two through which `offset` is divisible.
|
|
let offset_pow2 = 1 << offset.trailing_zeros();
|
|
M::alignment_check_failed(self, Align::from_bytes(offset_pow2).unwrap(), align, check)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Allocation accessors
|
|
impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
|
|
/// Helper function to obtain a global (tcx) allocation.
|
|
/// 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 provenance, so it is indirected through
|
|
/// `M::adjust_allocation`.
|
|
fn get_global_alloc(
|
|
&self,
|
|
id: AllocId,
|
|
is_write: bool,
|
|
) -> InterpResult<'tcx, Cow<'tcx, Allocation<M::Provenance, M::AllocExtra>>> {
|
|
let (alloc, def_id) = match self.tcx.try_get_global_alloc(id) {
|
|
Some(GlobalAlloc::Memory(mem)) => {
|
|
// Memory of a constant or promoted or anonymous memory referenced by a static.
|
|
(mem, None)
|
|
}
|
|
Some(GlobalAlloc::Function(..)) => throw_ub!(DerefFunctionPointer(id)),
|
|
Some(GlobalAlloc::VTable(..)) => throw_ub!(DerefVTablePointer(id)),
|
|
None => throw_ub!(PointerUseAfterFree(id)),
|
|
Some(GlobalAlloc::Static(def_id)) => {
|
|
assert!(self.tcx.is_static(def_id));
|
|
assert!(!self.tcx.is_thread_local_static(def_id));
|
|
// 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
|
|
// `eval_static_initializer` and it is the "resolved" ID.
|
|
// The resolved ID is never used by the interpreted program, it is hidden.
|
|
// This is relied upon for soundness of const-patterns; a pointer to the resolved
|
|
// ID would "sidestep" the checks that make sure consts do not point to statics!
|
|
// 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.
|
|
if self.tcx.is_foreign_item(def_id) {
|
|
// This is unreachable in Miri, but can happen in CTFE where we actually *do* support
|
|
// referencing arbitrary (declared) extern statics.
|
|
throw_unsup!(ReadExternStatic(def_id));
|
|
}
|
|
|
|
// We don't give a span -- statics don't need that, they cannot be generic or associated.
|
|
let val = self.ctfe_query(None, |tcx| tcx.eval_static_initializer(def_id))?;
|
|
(val, Some(def_id))
|
|
}
|
|
};
|
|
M::before_access_global(*self.tcx, &self.machine, id, alloc, def_id, is_write)?;
|
|
// We got tcx memory. Let the machine initialize its "extra" stuff.
|
|
M::adjust_allocation(
|
|
self,
|
|
id, // always use the ID we got as input, not the "hidden" one.
|
|
Cow::Borrowed(alloc.inner()),
|
|
M::GLOBAL_KIND.map(MemoryKind::Machine),
|
|
)
|
|
}
|
|
|
|
/// Gives raw access to the `Allocation`, without bounds or alignment checks.
|
|
/// The caller is responsible for calling the access hooks!
|
|
///
|
|
/// You almost certainly want to use `get_ptr_alloc`/`get_ptr_alloc_mut` instead.
|
|
fn get_alloc_raw(
|
|
&self,
|
|
id: AllocId,
|
|
) -> InterpResult<'tcx, &Allocation<M::Provenance, 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_global_alloc` that we can actually use directly without inserting anything anywhere.
|
|
// So the error type is `InterpResult<'tcx, &Allocation<M::Provenance>>`.
|
|
let a = self.memory.alloc_map.get_or(id, || {
|
|
let alloc = self.get_global_alloc(id, /*is_write*/ false).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::GLOBAL_KIND.expect(
|
|
"I got a global 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,
|
|
}
|
|
}
|
|
|
|
/// "Safe" (bounds and align-checked) allocation access.
|
|
pub fn get_ptr_alloc<'a>(
|
|
&'a self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
size: Size,
|
|
align: Align,
|
|
) -> InterpResult<'tcx, Option<AllocRef<'a, 'tcx, M::Provenance, M::AllocExtra>>> {
|
|
let ptr_and_alloc = self.check_and_deref_ptr(
|
|
ptr,
|
|
size,
|
|
align,
|
|
M::enforce_alignment(self),
|
|
CheckInAllocMsg::MemoryAccessTest,
|
|
|alloc_id, offset, prov| {
|
|
let alloc = self.get_alloc_raw(alloc_id)?;
|
|
Ok((alloc.size(), alloc.align, (alloc_id, offset, prov, alloc)))
|
|
},
|
|
)?;
|
|
if let Some((alloc_id, offset, prov, alloc)) = ptr_and_alloc {
|
|
let range = alloc_range(offset, size);
|
|
M::before_memory_read(*self.tcx, &self.machine, &alloc.extra, (alloc_id, prov), range)?;
|
|
Ok(Some(AllocRef { alloc, range, tcx: *self.tcx, alloc_id }))
|
|
} else {
|
|
// Even in this branch we have to be sure that we actually access the allocation, in
|
|
// order to ensure that `static FOO: Type = FOO;` causes a cycle error instead of
|
|
// magically pulling *any* ZST value from the ether. However, the `get_raw` above is
|
|
// always called when `ptr` has an `AllocId`.
|
|
Ok(None)
|
|
}
|
|
}
|
|
|
|
/// Return the `extra` field of the given allocation.
|
|
pub fn get_alloc_extra<'a>(&'a self, id: AllocId) -> InterpResult<'tcx, &'a M::AllocExtra> {
|
|
Ok(&self.get_alloc_raw(id)?.extra)
|
|
}
|
|
|
|
/// Return the `mutability` field of the given allocation.
|
|
pub fn get_alloc_mutability<'a>(&'a self, id: AllocId) -> InterpResult<'tcx, Mutability> {
|
|
Ok(self.get_alloc_raw(id)?.mutability)
|
|
}
|
|
|
|
/// Gives raw mutable access to the `Allocation`, without bounds or alignment checks.
|
|
/// The caller is responsible for calling the access hooks!
|
|
///
|
|
/// Also returns a ptr to `self.extra` so that the caller can use it in parallel with the
|
|
/// allocation.
|
|
fn get_alloc_raw_mut(
|
|
&mut self,
|
|
id: AllocId,
|
|
) -> InterpResult<'tcx, (&mut Allocation<M::Provenance, M::AllocExtra>, &mut M)> {
|
|
// We have "NLL problem case #3" here, which cannot be worked around without loss of
|
|
// efficiency even for the common case where the key is in the map.
|
|
// <https://rust-lang.github.io/rfcs/2094-nll.html#problem-case-3-conditional-control-flow-across-functions>
|
|
// (Cannot use `get_mut_or` since `get_global_alloc` needs `&self`.)
|
|
if self.memory.alloc_map.get_mut(id).is_none() {
|
|
// Slow path.
|
|
// Allocation not found locally, go look global.
|
|
let alloc = self.get_global_alloc(id, /*is_write*/ true)?;
|
|
let kind = M::GLOBAL_KIND.expect(
|
|
"I got a global allocation that I have to copy but the machine does \
|
|
not expect that to happen",
|
|
);
|
|
self.memory.alloc_map.insert(id, (MemoryKind::Machine(kind), alloc.into_owned()));
|
|
}
|
|
|
|
let (_kind, alloc) = self.memory.alloc_map.get_mut(id).unwrap();
|
|
if alloc.mutability == Mutability::Not {
|
|
throw_ub!(WriteToReadOnly(id))
|
|
}
|
|
Ok((alloc, &mut self.machine))
|
|
}
|
|
|
|
/// "Safe" (bounds and align-checked) allocation access.
|
|
pub fn get_ptr_alloc_mut<'a>(
|
|
&'a mut self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
size: Size,
|
|
align: Align,
|
|
) -> InterpResult<'tcx, Option<AllocRefMut<'a, 'tcx, M::Provenance, M::AllocExtra>>> {
|
|
let parts = self.get_ptr_access(ptr, size, align)?;
|
|
if let Some((alloc_id, offset, prov)) = parts {
|
|
let tcx = *self.tcx;
|
|
// FIXME: can we somehow avoid looking up the allocation twice here?
|
|
// We cannot call `get_raw_mut` inside `check_and_deref_ptr` as that would duplicate `&mut self`.
|
|
let (alloc, machine) = self.get_alloc_raw_mut(alloc_id)?;
|
|
let range = alloc_range(offset, size);
|
|
M::before_memory_write(tcx, machine, &mut alloc.extra, (alloc_id, prov), range)?;
|
|
Ok(Some(AllocRefMut { alloc, range, tcx, alloc_id }))
|
|
} else {
|
|
Ok(None)
|
|
}
|
|
}
|
|
|
|
/// Return the `extra` field of the given allocation.
|
|
pub fn get_alloc_extra_mut<'a>(
|
|
&'a mut self,
|
|
id: AllocId,
|
|
) -> InterpResult<'tcx, (&'a mut M::AllocExtra, &'a mut M)> {
|
|
let (alloc, machine) = self.get_alloc_raw_mut(id)?;
|
|
Ok((&mut alloc.extra, machine))
|
|
}
|
|
|
|
/// Obtain the size and alignment of an allocation, even if that allocation has
|
|
/// been deallocated.
|
|
pub fn get_alloc_info(&self, id: AllocId) -> (Size, Align, AllocKind) {
|
|
// # Regular allocations
|
|
// Don't use `self.get_raw` here as that will
|
|
// a) cause cycles in case `id` refers to a static
|
|
// b) duplicate a global's allocation in miri
|
|
if let Some((_, alloc)) = self.memory.alloc_map.get(id) {
|
|
return (alloc.size(), alloc.align, AllocKind::LiveData);
|
|
}
|
|
|
|
// # Function pointers
|
|
// (both global from `alloc_map` and local from `extra_fn_ptr_map`)
|
|
if self.get_fn_alloc(id).is_some() {
|
|
return (Size::ZERO, Align::ONE, AllocKind::Function);
|
|
}
|
|
|
|
// # Statics
|
|
// Can't do this in the match argument, we may get cycle errors since the lock would
|
|
// be held throughout the match.
|
|
match self.tcx.try_get_global_alloc(id) {
|
|
Some(GlobalAlloc::Static(def_id)) => {
|
|
assert!(self.tcx.is_static(def_id));
|
|
assert!(!self.tcx.is_thread_local_static(def_id));
|
|
// Use size and align of the type.
|
|
let ty = self.tcx.type_of(def_id);
|
|
let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap();
|
|
assert!(layout.is_sized());
|
|
(layout.size, layout.align.abi, AllocKind::LiveData)
|
|
}
|
|
Some(GlobalAlloc::Memory(alloc)) => {
|
|
// Need to duplicate the logic here, because the global allocations have
|
|
// different associated types than the interpreter-local ones.
|
|
let alloc = alloc.inner();
|
|
(alloc.size(), alloc.align, AllocKind::LiveData)
|
|
}
|
|
Some(GlobalAlloc::Function(_)) => bug!("We already checked function pointers above"),
|
|
Some(GlobalAlloc::VTable(..)) => {
|
|
// No data to be accessed here. But vtables are pointer-aligned.
|
|
return (Size::ZERO, self.tcx.data_layout.pointer_align.abi, AllocKind::VTable);
|
|
}
|
|
// The rest must be dead.
|
|
None => {
|
|
// Deallocated pointers are allowed, we should be able to find
|
|
// them in the map.
|
|
let (size, align) = *self
|
|
.memory
|
|
.dead_alloc_map
|
|
.get(&id)
|
|
.expect("deallocated pointers should all be recorded in `dead_alloc_map`");
|
|
(size, align, AllocKind::Dead)
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Obtain the size and alignment of a live allocation.
|
|
pub fn get_live_alloc_size_and_align(&self, id: AllocId) -> InterpResult<'tcx, (Size, Align)> {
|
|
let (size, align, kind) = self.get_alloc_info(id);
|
|
if matches!(kind, AllocKind::Dead) {
|
|
throw_ub!(PointerUseAfterFree(id))
|
|
}
|
|
Ok((size, align))
|
|
}
|
|
|
|
fn get_fn_alloc(&self, id: AllocId) -> Option<FnVal<'tcx, M::ExtraFnVal>> {
|
|
if let Some(extra) = self.memory.extra_fn_ptr_map.get(&id) {
|
|
Some(FnVal::Other(*extra))
|
|
} else {
|
|
match self.tcx.try_get_global_alloc(id) {
|
|
Some(GlobalAlloc::Function(instance)) => Some(FnVal::Instance(instance)),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|
|
|
|
pub fn get_ptr_fn(
|
|
&self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
) -> InterpResult<'tcx, FnVal<'tcx, M::ExtraFnVal>> {
|
|
trace!("get_ptr_fn({:?})", ptr);
|
|
let (alloc_id, offset, _prov) = self.ptr_get_alloc_id(ptr)?;
|
|
if offset.bytes() != 0 {
|
|
throw_ub!(InvalidFunctionPointer(Pointer::new(alloc_id, offset)))
|
|
}
|
|
self.get_fn_alloc(alloc_id)
|
|
.ok_or_else(|| err_ub!(InvalidFunctionPointer(Pointer::new(alloc_id, offset))).into())
|
|
}
|
|
|
|
pub fn get_ptr_vtable(
|
|
&self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
) -> InterpResult<'tcx, (Ty<'tcx>, Option<ty::PolyExistentialTraitRef<'tcx>>)> {
|
|
trace!("get_ptr_vtable({:?})", ptr);
|
|
let (alloc_id, offset, _tag) = self.ptr_get_alloc_id(ptr)?;
|
|
if offset.bytes() != 0 {
|
|
throw_ub!(InvalidVTablePointer(Pointer::new(alloc_id, offset)))
|
|
}
|
|
match self.tcx.try_get_global_alloc(alloc_id) {
|
|
Some(GlobalAlloc::VTable(ty, trait_ref)) => Ok((ty, trait_ref)),
|
|
_ => throw_ub!(InvalidVTablePointer(Pointer::new(alloc_id, offset))),
|
|
}
|
|
}
|
|
|
|
pub fn alloc_mark_immutable(&mut self, id: AllocId) -> InterpResult<'tcx> {
|
|
self.get_alloc_raw_mut(id)?.0.mutability = Mutability::Not;
|
|
Ok(())
|
|
}
|
|
|
|
/// Create a lazy debug printer that prints the given allocation and all allocations it points
|
|
/// to, recursively.
|
|
#[must_use]
|
|
pub fn dump_alloc<'a>(&'a self, id: AllocId) -> DumpAllocs<'a, 'mir, 'tcx, M> {
|
|
self.dump_allocs(vec![id])
|
|
}
|
|
|
|
/// Create a lazy debug printer for a list of allocations and all allocations they point to,
|
|
/// recursively.
|
|
#[must_use]
|
|
pub fn dump_allocs<'a>(&'a self, mut allocs: Vec<AllocId>) -> DumpAllocs<'a, 'mir, 'tcx, M> {
|
|
allocs.sort();
|
|
allocs.dedup();
|
|
DumpAllocs { ecx: self, allocs }
|
|
}
|
|
|
|
/// Print leaked memory. Allocations reachable from `static_roots` or a `Global` allocation
|
|
/// are not considered leaked. Leaks whose kind `may_leak()` returns true are not reported.
|
|
pub fn leak_report(&self, static_roots: &[AllocId]) -> usize {
|
|
// Collect the set of allocations that are *reachable* from `Global` allocations.
|
|
let reachable = {
|
|
let mut reachable = FxHashSet::default();
|
|
let global_kind = M::GLOBAL_KIND.map(MemoryKind::Machine);
|
|
let mut todo: Vec<_> =
|
|
self.memory.alloc_map.filter_map_collect(move |&id, &(kind, _)| {
|
|
if Some(kind) == global_kind { Some(id) } else { None }
|
|
});
|
|
todo.extend(static_roots);
|
|
while let Some(id) = todo.pop() {
|
|
if reachable.insert(id) {
|
|
// This is a new allocation, add the allocation it points to `todo`.
|
|
if let Some((_, alloc)) = self.memory.alloc_map.get(id) {
|
|
todo.extend(
|
|
alloc.provenance().provenances().filter_map(|prov| prov.get_alloc_id()),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
reachable
|
|
};
|
|
|
|
// All allocations that are *not* `reachable` and *not* `may_leak` are considered leaking.
|
|
let leaks: Vec<_> = self.memory.alloc_map.filter_map_collect(|&id, &(kind, _)| {
|
|
if kind.may_leak() || reachable.contains(&id) { None } else { Some(id) }
|
|
});
|
|
let n = leaks.len();
|
|
if n > 0 {
|
|
eprintln!("The following memory was leaked: {:?}", self.dump_allocs(leaks));
|
|
}
|
|
n
|
|
}
|
|
}
|
|
|
|
#[doc(hidden)]
|
|
/// There's no way to use this directly, it's just a helper struct for the `dump_alloc(s)` methods.
|
|
pub struct DumpAllocs<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> {
|
|
ecx: &'a InterpCx<'mir, 'tcx, M>,
|
|
allocs: Vec<AllocId>,
|
|
}
|
|
|
|
impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> std::fmt::Debug for DumpAllocs<'a, 'mir, 'tcx, M> {
|
|
fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
|
|
// Cannot be a closure because it is generic in `Prov`, `Extra`.
|
|
fn write_allocation_track_relocs<'tcx, Prov: Provenance, Extra>(
|
|
fmt: &mut std::fmt::Formatter<'_>,
|
|
tcx: TyCtxt<'tcx>,
|
|
allocs_to_print: &mut VecDeque<AllocId>,
|
|
alloc: &Allocation<Prov, Extra>,
|
|
) -> std::fmt::Result {
|
|
for alloc_id in alloc.provenance().provenances().filter_map(|prov| prov.get_alloc_id())
|
|
{
|
|
allocs_to_print.push_back(alloc_id);
|
|
}
|
|
write!(fmt, "{}", display_allocation(tcx, alloc))
|
|
}
|
|
|
|
let mut allocs_to_print: VecDeque<_> = self.allocs.iter().copied().collect();
|
|
// `allocs_printed` contains all allocations that we have already printed.
|
|
let mut allocs_printed = FxHashSet::default();
|
|
|
|
while let Some(id) = allocs_to_print.pop_front() {
|
|
if !allocs_printed.insert(id) {
|
|
// Already printed, so skip this.
|
|
continue;
|
|
}
|
|
|
|
write!(fmt, "{id:?}")?;
|
|
match self.ecx.memory.alloc_map.get(id) {
|
|
Some(&(kind, ref alloc)) => {
|
|
// normal alloc
|
|
write!(fmt, " ({}, ", kind)?;
|
|
write_allocation_track_relocs(
|
|
&mut *fmt,
|
|
*self.ecx.tcx,
|
|
&mut allocs_to_print,
|
|
alloc,
|
|
)?;
|
|
}
|
|
None => {
|
|
// global alloc
|
|
match self.ecx.tcx.try_get_global_alloc(id) {
|
|
Some(GlobalAlloc::Memory(alloc)) => {
|
|
write!(fmt, " (unchanged global, ")?;
|
|
write_allocation_track_relocs(
|
|
&mut *fmt,
|
|
*self.ecx.tcx,
|
|
&mut allocs_to_print,
|
|
alloc.inner(),
|
|
)?;
|
|
}
|
|
Some(GlobalAlloc::Function(func)) => {
|
|
write!(fmt, " (fn: {func})")?;
|
|
}
|
|
Some(GlobalAlloc::VTable(ty, Some(trait_ref))) => {
|
|
write!(fmt, " (vtable: impl {trait_ref} for {ty})")?;
|
|
}
|
|
Some(GlobalAlloc::VTable(ty, None)) => {
|
|
write!(fmt, " (vtable: impl <auto trait> for {ty})")?;
|
|
}
|
|
Some(GlobalAlloc::Static(did)) => {
|
|
write!(fmt, " (static: {})", self.ecx.tcx.def_path_str(did))?;
|
|
}
|
|
None => {
|
|
write!(fmt, " (deallocated)")?;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
writeln!(fmt)?;
|
|
}
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Reading and writing.
|
|
impl<'tcx, 'a, Prov: Provenance, Extra> AllocRefMut<'a, 'tcx, Prov, Extra> {
|
|
/// `range` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn write_scalar(&mut self, range: AllocRange, val: Scalar<Prov>) -> InterpResult<'tcx> {
|
|
let range = self.range.subrange(range);
|
|
debug!("write_scalar at {:?}{range:?}: {val:?}", self.alloc_id);
|
|
Ok(self
|
|
.alloc
|
|
.write_scalar(&self.tcx, range, val)
|
|
.map_err(|e| e.to_interp_error(self.alloc_id))?)
|
|
}
|
|
|
|
/// `offset` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn write_ptr_sized(&mut self, offset: Size, val: Scalar<Prov>) -> InterpResult<'tcx> {
|
|
self.write_scalar(alloc_range(offset, self.tcx.data_layout().pointer_size), val)
|
|
}
|
|
|
|
/// Mark the entire referenced range as uninitialized
|
|
pub fn write_uninit(&mut self) -> InterpResult<'tcx> {
|
|
Ok(self
|
|
.alloc
|
|
.write_uninit(&self.tcx, self.range)
|
|
.map_err(|e| e.to_interp_error(self.alloc_id))?)
|
|
}
|
|
}
|
|
|
|
impl<'tcx, 'a, Prov: Provenance, Extra> AllocRef<'a, 'tcx, Prov, Extra> {
|
|
/// `range` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn read_scalar(
|
|
&self,
|
|
range: AllocRange,
|
|
read_provenance: bool,
|
|
) -> InterpResult<'tcx, Scalar<Prov>> {
|
|
let range = self.range.subrange(range);
|
|
let res = self
|
|
.alloc
|
|
.read_scalar(&self.tcx, range, read_provenance)
|
|
.map_err(|e| e.to_interp_error(self.alloc_id))?;
|
|
debug!("read_scalar at {:?}{range:?}: {res:?}", self.alloc_id);
|
|
Ok(res)
|
|
}
|
|
|
|
/// `range` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn read_integer(&self, range: AllocRange) -> InterpResult<'tcx, Scalar<Prov>> {
|
|
self.read_scalar(range, /*read_provenance*/ false)
|
|
}
|
|
|
|
/// `offset` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn read_pointer(&self, offset: Size) -> InterpResult<'tcx, Scalar<Prov>> {
|
|
self.read_scalar(
|
|
alloc_range(offset, self.tcx.data_layout().pointer_size),
|
|
/*read_provenance*/ true,
|
|
)
|
|
}
|
|
|
|
/// `range` is relative to this allocation reference, not the base of the allocation.
|
|
pub fn get_bytes_strip_provenance<'b>(&'b self) -> InterpResult<'tcx, &'a [u8]> {
|
|
Ok(self
|
|
.alloc
|
|
.get_bytes_strip_provenance(&self.tcx, self.range)
|
|
.map_err(|e| e.to_interp_error(self.alloc_id))?)
|
|
}
|
|
|
|
/// Returns whether the allocation has provenance anywhere in the range of the `AllocRef`.
|
|
pub(crate) fn has_provenance(&self) -> bool {
|
|
!self.alloc.provenance().range_empty(self.range, &self.tcx)
|
|
}
|
|
}
|
|
|
|
impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
|
|
/// Reads the given number of bytes from memory, and strips their provenance if possible.
|
|
/// Returns them as a slice.
|
|
///
|
|
/// Performs appropriate bounds checks.
|
|
pub fn read_bytes_ptr_strip_provenance(
|
|
&self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
size: Size,
|
|
) -> InterpResult<'tcx, &[u8]> {
|
|
let Some(alloc_ref) = self.get_ptr_alloc(ptr, size, Align::ONE)? else {
|
|
// zero-sized access
|
|
return Ok(&[]);
|
|
};
|
|
// Side-step AllocRef and directly access the underlying bytes more efficiently.
|
|
// (We are staying inside the bounds here so all is good.)
|
|
Ok(alloc_ref
|
|
.alloc
|
|
.get_bytes_strip_provenance(&alloc_ref.tcx, alloc_ref.range)
|
|
.map_err(|e| e.to_interp_error(alloc_ref.alloc_id))?)
|
|
}
|
|
|
|
/// Writes the given stream of bytes into memory.
|
|
///
|
|
/// Performs appropriate bounds checks.
|
|
pub fn write_bytes_ptr(
|
|
&mut self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
src: impl IntoIterator<Item = u8>,
|
|
) -> InterpResult<'tcx> {
|
|
let mut src = src.into_iter();
|
|
let (lower, upper) = src.size_hint();
|
|
let len = upper.expect("can only write bounded iterators");
|
|
assert_eq!(lower, len, "can only write iterators with a precise length");
|
|
|
|
let size = Size::from_bytes(len);
|
|
let Some(alloc_ref) = self.get_ptr_alloc_mut(ptr, size, Align::ONE)? else {
|
|
// zero-sized access
|
|
assert_matches!(
|
|
src.next(),
|
|
None,
|
|
"iterator said it was empty but returned an element"
|
|
);
|
|
return Ok(());
|
|
};
|
|
|
|
// Side-step AllocRef and directly access the underlying bytes more efficiently.
|
|
// (We are staying inside the bounds here so all is good.)
|
|
let alloc_id = alloc_ref.alloc_id;
|
|
let bytes = alloc_ref
|
|
.alloc
|
|
.get_bytes_mut(&alloc_ref.tcx, alloc_ref.range)
|
|
.map_err(move |e| e.to_interp_error(alloc_id))?;
|
|
// `zip` would stop when the first iterator ends; we want to definitely
|
|
// cover all of `bytes`.
|
|
for dest in bytes {
|
|
*dest = src.next().expect("iterator was shorter than it said it would be");
|
|
}
|
|
assert_matches!(src.next(), None, "iterator was longer than it said it would be");
|
|
Ok(())
|
|
}
|
|
|
|
pub fn mem_copy(
|
|
&mut self,
|
|
src: Pointer<Option<M::Provenance>>,
|
|
src_align: Align,
|
|
dest: Pointer<Option<M::Provenance>>,
|
|
dest_align: Align,
|
|
size: Size,
|
|
nonoverlapping: bool,
|
|
) -> InterpResult<'tcx> {
|
|
self.mem_copy_repeatedly(src, src_align, dest, dest_align, size, 1, nonoverlapping)
|
|
}
|
|
|
|
pub fn mem_copy_repeatedly(
|
|
&mut self,
|
|
src: Pointer<Option<M::Provenance>>,
|
|
src_align: Align,
|
|
dest: Pointer<Option<M::Provenance>>,
|
|
dest_align: Align,
|
|
size: Size,
|
|
num_copies: u64,
|
|
nonoverlapping: bool,
|
|
) -> InterpResult<'tcx> {
|
|
let tcx = self.tcx;
|
|
// We need to do our own bounds-checks.
|
|
let src_parts = self.get_ptr_access(src, size, src_align)?;
|
|
let dest_parts = self.get_ptr_access(dest, size * num_copies, dest_align)?; // `Size` multiplication
|
|
|
|
// FIXME: we look up both allocations twice here, once before for the `check_ptr_access`
|
|
// and once below to get the underlying `&[mut] Allocation`.
|
|
|
|
// Source alloc preparations and access hooks.
|
|
let Some((src_alloc_id, src_offset, src_prov)) = src_parts else {
|
|
// Zero-sized *source*, that means dest is also zero-sized and we have nothing to do.
|
|
return Ok(());
|
|
};
|
|
let src_alloc = self.get_alloc_raw(src_alloc_id)?;
|
|
let src_range = alloc_range(src_offset, size);
|
|
M::before_memory_read(
|
|
*tcx,
|
|
&self.machine,
|
|
&src_alloc.extra,
|
|
(src_alloc_id, src_prov),
|
|
src_range,
|
|
)?;
|
|
// We need the `dest` ptr for the next operation, so we get it now.
|
|
// We already did the source checks and called the hooks so we are good to return early.
|
|
let Some((dest_alloc_id, dest_offset, dest_prov)) = dest_parts else {
|
|
// Zero-sized *destination*.
|
|
return Ok(());
|
|
};
|
|
|
|
// Prepare getting source provenance.
|
|
let src_bytes = src_alloc.get_bytes_unchecked(src_range).as_ptr(); // raw ptr, so we can also get a ptr to the destination allocation
|
|
// first copy the provenance to a temporary buffer, because
|
|
// `get_bytes_mut` will clear the provenance, which is correct,
|
|
// since we don't want to keep any provenance at the target.
|
|
// This will also error if copying partial provenance is not supported.
|
|
let provenance = src_alloc
|
|
.provenance()
|
|
.prepare_copy(src_range, dest_offset, num_copies, self)
|
|
.map_err(|e| e.to_interp_error(dest_alloc_id))?;
|
|
// Prepare a copy of the initialization mask.
|
|
let init = src_alloc.init_mask().prepare_copy(src_range);
|
|
|
|
// Destination alloc preparations and access hooks.
|
|
let (dest_alloc, extra) = self.get_alloc_raw_mut(dest_alloc_id)?;
|
|
let dest_range = alloc_range(dest_offset, size * num_copies);
|
|
M::before_memory_write(
|
|
*tcx,
|
|
extra,
|
|
&mut dest_alloc.extra,
|
|
(dest_alloc_id, dest_prov),
|
|
dest_range,
|
|
)?;
|
|
let dest_bytes = dest_alloc
|
|
.get_bytes_mut_ptr(&tcx, dest_range)
|
|
.map_err(|e| e.to_interp_error(dest_alloc_id))?
|
|
.as_mut_ptr();
|
|
|
|
if init.no_bytes_init() {
|
|
// Fast path: If all bytes are `uninit` then there is nothing to copy. The target range
|
|
// is marked as uninitialized but we otherwise omit changing the byte representation which may
|
|
// be arbitrary for uninitialized bytes.
|
|
// This also avoids writing to the target bytes so that the backing allocation is never
|
|
// touched if the bytes stay uninitialized for the whole interpreter execution. On contemporary
|
|
// operating system this can avoid physically allocating the page.
|
|
dest_alloc
|
|
.write_uninit(&tcx, dest_range)
|
|
.map_err(|e| e.to_interp_error(dest_alloc_id))?;
|
|
// We can forget about the provenance, this is all not initialized anyway.
|
|
return Ok(());
|
|
}
|
|
|
|
// 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 {
|
|
if src_alloc_id == dest_alloc_id {
|
|
if nonoverlapping {
|
|
// `Size` additions
|
|
if (src_offset <= dest_offset && src_offset + size > dest_offset)
|
|
|| (dest_offset <= src_offset && dest_offset + size > src_offset)
|
|
{
|
|
throw_ub_format!("copy_nonoverlapping called on overlapping ranges")
|
|
}
|
|
}
|
|
|
|
for i in 0..num_copies {
|
|
ptr::copy(
|
|
src_bytes,
|
|
dest_bytes.add((size * i).bytes_usize()), // `Size` multiplication
|
|
size.bytes_usize(),
|
|
);
|
|
}
|
|
} else {
|
|
for i in 0..num_copies {
|
|
ptr::copy_nonoverlapping(
|
|
src_bytes,
|
|
dest_bytes.add((size * i).bytes_usize()), // `Size` multiplication
|
|
size.bytes_usize(),
|
|
);
|
|
}
|
|
}
|
|
}
|
|
|
|
// now fill in all the "init" data
|
|
dest_alloc.init_mask_apply_copy(
|
|
init,
|
|
alloc_range(dest_offset, size), // just a single copy (i.e., not full `dest_range`)
|
|
num_copies,
|
|
);
|
|
// copy the provenance to the destination
|
|
dest_alloc.provenance_apply_copy(provenance);
|
|
|
|
Ok(())
|
|
}
|
|
}
|
|
|
|
/// Machine pointer introspection.
|
|
impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
|
|
/// Test if this value might be null.
|
|
/// If the machine does not support ptr-to-int casts, this is conservative.
|
|
pub fn scalar_may_be_null(&self, scalar: Scalar<M::Provenance>) -> InterpResult<'tcx, bool> {
|
|
Ok(match scalar.try_to_int() {
|
|
Ok(int) => int.is_null(),
|
|
Err(_) => {
|
|
// Can only happen during CTFE.
|
|
let ptr = scalar.to_pointer(self)?;
|
|
match self.ptr_try_get_alloc_id(ptr) {
|
|
Ok((alloc_id, offset, _)) => {
|
|
let (size, _align, _kind) = self.get_alloc_info(alloc_id);
|
|
// If the pointer is out-of-bounds, it may be null.
|
|
// Note that one-past-the-end (offset == size) is still inbounds, and never null.
|
|
offset > size
|
|
}
|
|
Err(_offset) => bug!("a non-int scalar is always a pointer"),
|
|
}
|
|
}
|
|
})
|
|
}
|
|
|
|
/// Turning a "maybe pointer" into a proper pointer (and some information
|
|
/// about where it points), or an absolute address.
|
|
pub fn ptr_try_get_alloc_id(
|
|
&self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
) -> Result<(AllocId, Size, M::ProvenanceExtra), u64> {
|
|
match ptr.into_pointer_or_addr() {
|
|
Ok(ptr) => match M::ptr_get_alloc(self, ptr) {
|
|
Some((alloc_id, offset, extra)) => Ok((alloc_id, offset, extra)),
|
|
None => {
|
|
assert!(M::Provenance::OFFSET_IS_ADDR);
|
|
let (_, addr) = ptr.into_parts();
|
|
Err(addr.bytes())
|
|
}
|
|
},
|
|
Err(addr) => Err(addr.bytes()),
|
|
}
|
|
}
|
|
|
|
/// Turning a "maybe pointer" into a proper pointer (and some information about where it points).
|
|
#[inline(always)]
|
|
pub fn ptr_get_alloc_id(
|
|
&self,
|
|
ptr: Pointer<Option<M::Provenance>>,
|
|
) -> InterpResult<'tcx, (AllocId, Size, M::ProvenanceExtra)> {
|
|
self.ptr_try_get_alloc_id(ptr).map_err(|offset| {
|
|
err_ub!(DanglingIntPointer(offset, CheckInAllocMsg::InboundsTest)).into()
|
|
})
|
|
}
|
|
}
|