diff options
Diffstat (limited to 'compiler/rustc_const_eval/src')
4 files changed, 87 insertions, 154 deletions
diff --git a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs index 4055e3f0d50..a430d9dc797 100644 --- a/compiler/rustc_const_eval/src/const_eval/eval_queries.rs +++ b/compiler/rustc_const_eval/src/const_eval/eval_queries.rs @@ -472,8 +472,9 @@ fn report_validation_error<'tcx>( backtrace.print_backtrace(); let bytes = ecx.print_alloc_bytes_for_diagnostics(alloc_id); - let (size, align, ..) = ecx.get_alloc_info(alloc_id); - let raw_bytes = errors::RawBytesNote { size: size.bytes(), align: align.bytes(), bytes }; + let info = ecx.get_alloc_info(alloc_id); + let raw_bytes = + errors::RawBytesNote { size: info.size.bytes(), align: info.align.bytes(), bytes }; crate::const_eval::report( *ecx.tcx, diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs index cc7ce1df923..09635c96e57 100644 --- a/compiler/rustc_const_eval/src/interpret/memory.rs +++ b/compiler/rustc_const_eval/src/interpret/memory.rs @@ -14,10 +14,9 @@ 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_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, _mutbl) = 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) } @@ -818,93 +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, Mutability) { + 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, alloc.mutability); + 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, Mutability::Not); + 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, mutability, .. } = self.tcx.def_kind(def_id) else { - bug!("GlobalAlloc::Static is not a static") - }; - - let (size, align, mutability) = 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, alloc.0.mutability) - } 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()); - let mutability = match mutability { - Mutability::Not if !ty.is_freeze(*self.tcx, ParamEnv::empty()) => { - Mutability::Not - } - _ => Mutability::Mut, - }; - (layout.size, layout.align.abi, mutability) - }; - (size, align, AllocKind::LiveData, mutability) - } - 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, alloc.mutability) - } - 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, - Mutability::Not, - ); - } - // 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, Mutability::Not) - } + // # 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.param_env); + let mutbl = global_alloc.mutability(*self.tcx, self.param_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. @@ -913,11 +884,11 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> { id: AllocId, msg: CheckInAllocMsg, ) -> InterpResult<'tcx, (Size, Align)> { - let (size, align, kind, _mutbl) = 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>> { @@ -1469,7 +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, _mutbl) = 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 diff --git a/compiler/rustc_const_eval/src/interpret/mod.rs b/compiler/rustc_const_eval/src/interpret/mod.rs index 5e84626f77e..f5792aba207 100644 --- a/compiler/rustc_const_eval/src/interpret/mod.rs +++ b/compiler/rustc_const_eval/src/interpret/mod.rs @@ -31,7 +31,7 @@ pub use self::intern::{ }; pub(crate) use self::intrinsics::eval_nullary_intrinsic; pub use self::machine::{AllocMap, Machine, MayLeak, ReturnAction, compile_time_machine}; -pub use self::memory::{AllocKind, AllocRef, AllocRefMut, FnVal, Memory, MemoryKind}; +pub use self::memory::{AllocInfo, AllocKind, AllocRef, AllocRefMut, FnVal, Memory, MemoryKind}; use self::operand::Operand; pub use self::operand::{ImmTy, Immediate, OpTy}; pub use self::place::{MPlaceTy, MemPlaceMeta, PlaceTy, Writeable}; diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs index d7532c6e01a..3a68db9f7f7 100644 --- a/compiler/rustc_const_eval/src/interpret/validity.rs +++ b/compiler/rustc_const_eval/src/interpret/validity.rs @@ -31,8 +31,8 @@ use tracing::trace; use super::machine::AllocMap; use super::{ - AllocId, AllocKind, CheckInAllocMsg, GlobalAlloc, ImmTy, Immediate, InterpCx, InterpResult, - MPlaceTy, Machine, MemPlaceMeta, PlaceTy, Pointer, Projectable, Scalar, ValueVisitor, err_ub, + AllocId, CheckInAllocMsg, GlobalAlloc, ImmTy, Immediate, InterpCx, InterpResult, MPlaceTy, + Machine, MemPlaceMeta, PlaceTy, Pointer, Projectable, Scalar, ValueVisitor, err_ub, format_interp_error, }; @@ -557,9 +557,20 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { if let Ok((alloc_id, _offset, _prov)) = self.ecx.ptr_try_get_alloc_id(place.ptr(), 0) { - if let Some(GlobalAlloc::Static(did)) = - self.ecx.tcx.try_get_global_alloc(alloc_id) - { + // Everything should be already interned. + let Some(global_alloc) = self.ecx.tcx.try_get_global_alloc(alloc_id) else { + assert!(self.ecx.memory.alloc_map.get(alloc_id).is_none()); + // We can't have *any* references to non-existing allocations in const-eval + // as the rest of rustc isn't happy with them... so we throw an error, even + // though for zero-sized references this isn't really UB. + // A potential future alternative would be to resurrect this as a zero-sized allocation + // (which codegen will then compile to an aligned dummy pointer anyway). + throw_validation_failure!(self.path, DanglingPtrUseAfterFree { ptr_kind }); + }; + let (size, _align) = + global_alloc.size_and_align(*self.ecx.tcx, self.ecx.param_env); + + if let GlobalAlloc::Static(did) = global_alloc { let DefKind::Static { nested, .. } = self.ecx.tcx.def_kind(did) else { bug!() }; @@ -593,17 +604,6 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { } } - // Dangling and Mutability check. - let (size, _align, alloc_kind, _mutbl) = self.ecx.get_alloc_info(alloc_id); - if alloc_kind == AllocKind::Dead { - // This can happen for zero-sized references. We can't have *any* references to - // non-existing allocations in const-eval though, interning rejects them all as - // the rest of rustc isn't happy with them... so we throw an error, even though - // this isn't really UB. - // A potential future alternative would be to resurrect this as a zero-sized allocation - // (which codegen will then compile to an aligned dummy pointer anyway). - throw_validation_failure!(self.path, DanglingPtrUseAfterFree { ptr_kind }); - } // If this allocation has size zero, there is no actual mutability here. if size != Size::ZERO { // Determine whether this pointer expects to be pointing to something mutable. @@ -618,7 +618,8 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { } }; // Determine what it actually points to. - let alloc_actual_mutbl = mutability(self.ecx, alloc_id); + let alloc_actual_mutbl = + global_alloc.mutability(*self.ecx.tcx, self.ecx.param_env); // Mutable pointer to immutable memory is no good. if ptr_expected_mutbl == Mutability::Mut && alloc_actual_mutbl == Mutability::Not @@ -842,9 +843,16 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { } fn in_mutable_memory(&self, val: &PlaceTy<'tcx, M::Provenance>) -> bool { + debug_assert!(self.ctfe_mode.is_some()); if let Some(mplace) = val.as_mplace_or_local().left() { if let Some(alloc_id) = mplace.ptr().provenance.and_then(|p| p.get_alloc_id()) { - mutability(self.ecx, alloc_id).is_mut() + let tcx = *self.ecx.tcx; + // Everything must be already interned. + let mutbl = tcx.global_alloc(alloc_id).mutability(tcx, self.ecx.param_env); + if let Some((_, alloc)) = self.ecx.memory.alloc_map.get(alloc_id) { + assert_eq!(alloc.mutability, mutbl); + } + mutbl.is_mut() } else { // No memory at all. false @@ -1016,53 +1024,6 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValidityVisitor<'rt, 'tcx, M> { } } -/// Returns whether the allocation is mutable, and whether it's actually a static. -/// For "root" statics we look at the type to account for interior -/// mutability; for nested statics we have no type and directly use the annotated mutability. -fn mutability<'tcx>(ecx: &InterpCx<'tcx, impl Machine<'tcx>>, alloc_id: AllocId) -> Mutability { - // Let's see what kind of memory this points to. - // We're not using `try_global_alloc` since dangling pointers have already been handled. - match ecx.tcx.global_alloc(alloc_id) { - GlobalAlloc::Static(did) => { - let DefKind::Static { safety: _, mutability, nested } = ecx.tcx.def_kind(did) else { - bug!() - }; - if nested { - assert!( - ecx.memory.alloc_map.get(alloc_id).is_none(), - "allocations of nested statics are already interned: {alloc_id:?}, {did:?}" - ); - // Nested statics in a `static` are never interior mutable, - // so just use the declared mutability. - mutability - } else { - let mutability = match mutability { - Mutability::Not - if !ecx - .tcx - .type_of(did) - .no_bound_vars() - .expect("statics should not have generic parameters") - .is_freeze(*ecx.tcx, ty::ParamEnv::reveal_all()) => - { - Mutability::Mut - } - _ => mutability, - }; - if let Some((_, alloc)) = ecx.memory.alloc_map.get(alloc_id) { - assert_eq!(alloc.mutability, mutability); - } - mutability - } - } - GlobalAlloc::Memory(alloc) => alloc.inner().mutability, - GlobalAlloc::Function { .. } | GlobalAlloc::VTable(..) => { - // These are immutable, we better don't allow mutable pointers here. - Mutability::Not - } - } -} - impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt, 'tcx, M> { type V = PlaceTy<'tcx, M::Provenance>; |