diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/interpret/memory.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/memory.rs | 134 |
1 files changed, 58 insertions, 76 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs index 7700eb792ef..277d293597a 100644 --- a/compiler/rustc_const_eval/src/interpret/memory.rs +++ b/compiler/rustc_const_eval/src/interpret/memory.rs @@ -11,13 +11,12 @@ use std::borrow::{Borrow, Cow}; use std::collections::VecDeque; use std::{fmt, mem, ptr}; +use rustc_abi::{Align, HasDataLayout, Size}; use rustc_ast::Mutability; use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; -use rustc_hir::def::DefKind; use rustc_middle::bug; use rustc_middle::mir::display_allocation; -use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TyCtxt}; -use rustc_target::abi::{Align, HasDataLayout, Size}; +use rustc_middle::ty::{self, Instance, Ty, TyCtxt}; use tracing::{debug, instrument, trace}; use super::{ @@ -72,6 +71,21 @@ pub enum AllocKind { Dead, } +/// Metadata about an `AllocId`. +#[derive(Copy, Clone, PartialEq, Debug)] +pub struct AllocInfo { + pub size: Size, + pub align: Align, + pub kind: AllocKind, + pub mutbl: Mutability, +} + +impl AllocInfo { + fn new(size: Size, align: Align, kind: AllocKind, mutbl: Mutability) -> Self { + Self { size, align, kind, mutbl } + } +} + /// The value of a function pointer. #[derive(Debug, Copy, Clone)] pub enum FnVal<'tcx, Other> { @@ -524,17 +538,22 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { match self.ptr_try_get_alloc_id(ptr, 0) { Err(addr) => is_offset_misaligned(addr, align), Ok((alloc_id, offset, _prov)) => { - let (_size, alloc_align, kind) = self.get_alloc_info(alloc_id); - if let Some(misalign) = - M::alignment_check(self, alloc_id, alloc_align, kind, offset, align) - { + let alloc_info = self.get_alloc_info(alloc_id); + if let Some(misalign) = M::alignment_check( + self, + alloc_id, + alloc_info.align, + alloc_info.kind, + offset, + align, + ) { Some(misalign) } else if M::Provenance::OFFSET_IS_ADDR { is_offset_misaligned(ptr.addr().bytes(), align) } else { // Check allocation alignment and offset alignment. - if alloc_align.bytes() < align.bytes() { - Some(Misalignment { has: alloc_align, required: align }) + if alloc_info.align.bytes() < align.bytes() { + Some(Misalignment { has: alloc_info.align, required: align }) } else { is_offset_misaligned(offset.bytes(), align) } @@ -818,82 +837,45 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { /// 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) { + pub fn get_alloc_info(&self, id: AllocId) -> AllocInfo { // # 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); + return AllocInfo::new( + alloc.size(), + alloc.align, + AllocKind::LiveData, + alloc.mutability, + ); } // # 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); + return AllocInfo::new(Size::ZERO, Align::ONE, AllocKind::Function, Mutability::Not); } - // # 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)) => { - // Thread-local statics do not have a constant address. They *must* be accessed via - // `ThreadLocalRef`; we can never have a pointer to them as a regular constant value. - assert!(!self.tcx.is_thread_local_static(def_id)); - - let DefKind::Static { nested, .. } = self.tcx.def_kind(def_id) else { - bug!("GlobalAlloc::Static is not a static") - }; - - let (size, align) = if nested { - // Nested anonymous statics are untyped, so let's get their - // size and alignment from the allocation itself. This always - // succeeds, as the query is fed at DefId creation time, so no - // evaluation actually occurs. - let alloc = self.tcx.eval_static_initializer(def_id).unwrap(); - (alloc.0.size(), alloc.0.align) - } else { - // Use size and align of the type for everything else. We need - // to do that to - // * avoid cycle errors in case of self-referential statics, - // * be able to get information on extern statics. - let ty = self - .tcx - .type_of(def_id) - .no_bound_vars() - .expect("statics should not have generic parameters"); - let layout = self.tcx.layout_of(ParamEnv::empty().and(ty)).unwrap(); - assert!(layout.is_sized()); - (layout.size, layout.align.abi) - }; - (size, align, 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) - } + // # Global allocations + if let Some(global_alloc) = self.tcx.try_get_global_alloc(id) { + 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::Function { .. } => bug!("We already checked function pointers above"), + GlobalAlloc::VTable { .. } => AllocKind::VTable, + }; + return AllocInfo::new(size, align, kind, mutbl); } + + // # Dead pointers + let (size, align) = *self + .memory + .dead_alloc_map + .get(&id) + .expect("deallocated pointers should all be recorded in `dead_alloc_map`"); + AllocInfo::new(size, align, AllocKind::Dead, Mutability::Not) } /// Obtain the size and alignment of a *live* allocation. @@ -902,11 +884,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { id: AllocId, msg: CheckInAllocMsg, ) -> InterpResult<'tcx, (Size, Align)> { - let (size, align, kind) = self.get_alloc_info(id); - if matches!(kind, AllocKind::Dead) { + let info = self.get_alloc_info(id); + if matches!(info.kind, AllocKind::Dead) { throw_ub!(PointerUseAfterFree(id, msg)) } - interp_ok((size, align)) + interp_ok((info.size, info.align)) } fn get_fn_alloc(&self, id: AllocId) -> Option<FnVal<'tcx, M::ExtraFnVal>> { @@ -1458,7 +1440,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { let ptr = scalar.to_pointer(self)?; match self.ptr_try_get_alloc_id(ptr, 0) { Ok((alloc_id, offset, _)) => { - let (size, _align, _kind) = self.get_alloc_info(alloc_id); + let size = self.get_alloc_info(alloc_id).size; // 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 |