diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/interpret/memory.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/memory.rs | 104 |
1 files changed, 62 insertions, 42 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs index 69fceb02ff9..6414821e21d 100644 --- a/compiler/rustc_const_eval/src/interpret/memory.rs +++ b/compiler/rustc_const_eval/src/interpret/memory.rs @@ -15,9 +15,9 @@ use std::{fmt, ptr}; use rustc_abi::{Align, HasDataLayout, Size}; use rustc_ast::Mutability; use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; -use rustc_middle::bug; use rustc_middle::mir::display_allocation; use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; +use rustc_middle::{bug, throw_ub_format}; use tracing::{debug, instrument, trace}; use super::{ @@ -346,6 +346,13 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { kind = "vtable", ) } + Some(GlobalAlloc::TypeId { .. }) => { + err_ub_custom!( + fluent::const_eval_invalid_dealloc, + alloc_id = alloc_id, + kind = "typeid", + ) + } Some(GlobalAlloc::Static(..) | GlobalAlloc::Memory(..)) => { err_ub_custom!( fluent::const_eval_invalid_dealloc, @@ -537,7 +544,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { #[inline] fn is_offset_misaligned(offset: u64, align: Align) -> Option<Misalignment> { - if offset % align.bytes() == 0 { + if offset.is_multiple_of(align.bytes()) { None } else { // The biggest power of two through which `offset` is divisible. @@ -615,6 +622,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { } Some(GlobalAlloc::Function { .. }) => throw_ub!(DerefFunctionPointer(id)), Some(GlobalAlloc::VTable(..)) => throw_ub!(DerefVTablePointer(id)), + Some(GlobalAlloc::TypeId { .. }) => throw_ub!(DerefTypeIdPointer(id)), None => throw_ub!(PointerUseAfterFree(id, CheckInAllocMsg::MemoryAccess)), Some(GlobalAlloc::Static(def_id)) => { assert!(self.tcx.is_static(def_id)); @@ -655,7 +663,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { /// 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( + pub fn get_alloc_raw( &self, id: AllocId, ) -> InterpResult<'tcx, &Allocation<M::Provenance, M::AllocExtra, M::Bytes>> { @@ -757,7 +765,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { /// /// Also returns a ptr to `self.extra` so that the caller can use it in parallel with the /// allocation. - fn get_alloc_raw_mut( + /// + /// You almost certainly want to use `get_ptr_alloc`/`get_ptr_alloc_mut` instead. + pub fn get_alloc_raw_mut( &mut self, id: AllocId, ) -> InterpResult<'tcx, (&mut Allocation<M::Provenance, M::AllocExtra, M::Bytes>, &mut M)> { @@ -894,7 +904,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { let (size, align) = global_alloc.size_and_align(*self.tcx, self.typing_env); let mutbl = global_alloc.mutability(*self.tcx, self.typing_env); let kind = match global_alloc { - GlobalAlloc::Static { .. } | GlobalAlloc::Memory { .. } => AllocKind::LiveData, + GlobalAlloc::TypeId { .. } + | GlobalAlloc::Static { .. } + | GlobalAlloc::Memory { .. } => AllocKind::LiveData, GlobalAlloc::Function { .. } => bug!("We already checked function pointers above"), GlobalAlloc::VTable { .. } => AllocKind::VTable, }; @@ -934,6 +946,19 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { } } + /// Takes a pointer that is the first chunk of a `TypeId` and return the type that its + /// provenance refers to, as well as the segment of the hash that this pointer covers. + pub fn get_ptr_type_id( + &self, + ptr: Pointer<Option<M::Provenance>>, + ) -> InterpResult<'tcx, (Ty<'tcx>, Size)> { + let (alloc_id, offset, _meta) = self.ptr_get_alloc_id(ptr, 0)?; + let GlobalAlloc::TypeId { ty } = self.tcx.global_alloc(alloc_id) else { + throw_ub_format!("type_id_eq: `TypeId` provenance is not a type id") + }; + interp_ok((ty, offset)) + } + pub fn get_ptr_fn( &self, ptr: Pointer<Option<M::Provenance>>, @@ -976,15 +1001,15 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { interp_ok(()) } - /// Handle the effect an FFI call might have on the state of allocations. - /// This overapproximates the modifications which external code might make to memory: - /// We set all reachable allocations as initialized, mark all reachable provenances as exposed - /// and overwrite them with `Provenance::WILDCARD`. - /// - /// The allocations in `ids` are assumed to be already exposed. - pub fn prepare_for_native_call(&mut self, ids: Vec<AllocId>) -> InterpResult<'tcx> { + /// Visit all allocations reachable from the given start set, by recursively traversing the + /// provenance information of those allocations. + pub fn visit_reachable_allocs( + &mut self, + start: Vec<AllocId>, + mut visit: impl FnMut(&mut Self, AllocId, &AllocInfo) -> InterpResult<'tcx>, + ) -> InterpResult<'tcx> { let mut done = FxHashSet::default(); - let mut todo = ids; + let mut todo = start; while let Some(id) = todo.pop() { if !done.insert(id) { // We already saw this allocation before, don't process it again. @@ -992,31 +1017,20 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { } let info = self.get_alloc_info(id); - // If there is no data behind this pointer, skip this. - if !matches!(info.kind, AllocKind::LiveData) { - continue; - } - - // Expose all provenances in this allocation, and add them to `todo`. - let alloc = self.get_alloc_raw(id)?; - for prov in alloc.provenance().provenances() { - M::expose_provenance(self, prov)?; - if let Some(id) = prov.get_alloc_id() { - todo.push(id); + // Recurse, if there is data here. + // Do this *before* invoking the callback, as the callback might mutate the + // allocation and e.g. replace all provenance by wildcards! + if matches!(info.kind, AllocKind::LiveData) { + let alloc = self.get_alloc_raw(id)?; + for prov in alloc.provenance().provenances() { + if let Some(id) = prov.get_alloc_id() { + todo.push(id); + } } } - // Also expose the provenance of the interpreter-level allocation, so it can - // be read by FFI. The `black_box` is defensive programming as LLVM likes - // to (incorrectly) optimize away ptr2int casts whose result is unused. - std::hint::black_box(alloc.get_bytes_unchecked_raw().expose_provenance()); - - // Prepare for possible write from native code if mutable. - if info.mutbl.is_mut() { - self.get_alloc_raw_mut(id)? - .0 - .prepare_for_native_write() - .map_err(|e| e.to_interp_error(id))?; - } + + // Call the callback. + visit(self, id, &info)?; } interp_ok(()) } @@ -1073,7 +1087,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { todo.extend(static_roots(self)); while let Some(id) = todo.pop() { if reachable.insert(id) { - // This is a new allocation, add the allocation it points to `todo`. + // This is a new allocation, add the allocations it points to `todo`. + // We only need to care about `alloc_map` memory here, as entirely unchanged + // global memory cannot point to memory relevant for the leak check. if let Some((_, alloc)) = self.memory.alloc_map.get(id) { todo.extend( alloc.provenance().provenances().filter_map(|prov| prov.get_alloc_id()), @@ -1204,6 +1220,9 @@ impl<'a, 'tcx, M: Machine<'tcx>> std::fmt::Debug for DumpAllocs<'a, 'tcx, M> { Some(GlobalAlloc::VTable(ty, dyn_ty)) => { write!(fmt, " (vtable: impl {dyn_ty} for {ty})")?; } + Some(GlobalAlloc::TypeId { ty }) => { + write!(fmt, " (typeid for {ty})")?; + } Some(GlobalAlloc::Static(did)) => { write!(fmt, " (static: {})", self.ecx.tcx.def_path_str(did))?; } @@ -1240,7 +1259,7 @@ impl<'a, 'tcx, Prov: Provenance, Extra, Bytes: AllocBytes> /// `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) + self.write_scalar(alloc_range(offset, self.tcx.data_layout().pointer_size()), val) } /// Mark the given sub-range (relative to this allocation reference) as uninitialized. @@ -1292,7 +1311,7 @@ impl<'a, 'tcx, Prov: Provenance, Extra, Bytes: AllocBytes> AllocRef<'a, 'tcx, Pr /// `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), + alloc_range(offset, self.tcx.data_layout().pointer_size()), /*read_provenance*/ true, ) } @@ -1479,7 +1498,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { 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. + // `write_uninit` also resets the provenance, so we are done. return interp_ok(()); } @@ -1561,7 +1580,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { // If the allocation is N-aligned, and the offset is not divisible by N, // then `base + offset` has a non-zero remainder after division by `N`, // which means `base + offset` cannot be null. - if offset.bytes() % info.align.bytes() != 0 { + if !offset.bytes().is_multiple_of(info.align.bytes()) { return interp_ok(false); } // We don't know enough, this might be null. @@ -1596,7 +1615,8 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { Some((alloc_id, offset, extra)) => Ok((alloc_id, offset, extra)), None => { assert!(M::Provenance::OFFSET_IS_ADDR); - let (_, addr) = ptr.into_parts(); + // Offset is absolute, as we just asserted. + let (_, addr) = ptr.into_raw_parts(); Err(addr.bytes()) } }, |