diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/interpret/intern.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/intern.rs | 97 |
1 files changed, 57 insertions, 40 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/intern.rs b/compiler/rustc_const_eval/src/interpret/intern.rs index bb59b9f5418..5d510a98352 100644 --- a/compiler/rustc_const_eval/src/interpret/intern.rs +++ b/compiler/rustc_const_eval/src/interpret/intern.rs @@ -19,9 +19,12 @@ use rustc_data_structures::fx::{FxHashSet, FxIndexMap}; use rustc_hir as hir; use rustc_hir::definitions::{DefPathData, DisambiguatorState}; use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs; -use rustc_middle::mir::interpret::{ConstAllocation, CtfeProvenance, InterpResult}; +use rustc_middle::mir::interpret::{ + AllocBytes, ConstAllocation, CtfeProvenance, InterpResult, Provenance, +}; use rustc_middle::query::TyCtxtAt; use rustc_middle::span_bug; +use rustc_middle::ty::TyCtxt; use rustc_middle::ty::layout::TyAndLayout; use rustc_span::def_id::LocalDefId; use tracing::{instrument, trace}; @@ -52,39 +55,30 @@ impl HasStaticRootDefId for const_eval::CompileTimeMachine<'_> { } } -/// Intern an allocation. Returns `Err` if the allocation does not exist in the local memory. -/// -/// `mutability` can be used to force immutable interning: if it is `Mutability::Not`, the -/// allocation is interned immutably; if it is `Mutability::Mut`, then the allocation *must be* -/// already mutable (as a sanity check). -/// -/// Returns an iterator over all relocations referred to by this allocation. -fn intern_shallow<'tcx, M: CompileTimeMachine<'tcx>>( - ecx: &mut InterpCx<'tcx, M>, - alloc_id: AllocId, +fn prepare_alloc<'tcx, Prov: Provenance, Extra, Bytes: AllocBytes>( + tcx: TyCtxt<'tcx>, + kind: MemoryKind<const_eval::MemoryKind>, + alloc: &mut Allocation<Prov, Extra, Bytes>, mutability: Mutability, - disambiguator: Option<&mut DisambiguatorState>, -) -> Result<impl Iterator<Item = CtfeProvenance> + 'tcx, InternError> { - trace!("intern_shallow {:?}", alloc_id); - // remove allocation - // FIXME(#120456) - is `swap_remove` correct? - let Some((kind, mut alloc)) = ecx.memory.alloc_map.swap_remove(&alloc_id) else { - return Err(InternError::DanglingPointer); - }; - +) -> Result<(), InternError> { match kind { MemoryKind::Machine(const_eval::MemoryKind::Heap { was_made_global }) => { if !was_made_global { // Attempting to intern a `const_allocate`d pointer that was not made global via - // `const_make_global`. We want to error here, but we have to first put the - // allocation back into the `alloc_map` to keep things in a consistent state. - ecx.memory.alloc_map.insert(alloc_id, (kind, alloc)); + // `const_make_global`. + tcx.dcx().delayed_bug("non-global heap allocation in const value"); return Err(InternError::ConstAllocNotGlobal); } } MemoryKind::Stack | MemoryKind::CallerLocation => {} } + if !alloc.provenance_merge_bytes(&tcx) { + // Per-byte provenance is not supported by backends, so we cannot accept it here. + tcx.dcx().delayed_bug("partial pointer in const value"); + return Err(InternError::PartialPointer); + } + // Set allocation mutability as appropriate. This is used by LLVM to put things into // read-only memory, and also by Miri when evaluating other globals that // access this one. @@ -97,6 +91,36 @@ fn intern_shallow<'tcx, M: CompileTimeMachine<'tcx>>( assert_eq!(alloc.mutability, Mutability::Mut); } } + Ok(()) +} + +/// Intern an allocation. Returns `Err` if the allocation does not exist in the local memory. +/// +/// `mutability` can be used to force immutable interning: if it is `Mutability::Not`, the +/// allocation is interned immutably; if it is `Mutability::Mut`, then the allocation *must be* +/// already mutable (as a sanity check). +/// +/// Returns an iterator over all relocations referred to by this allocation. +fn intern_shallow<'tcx, M: CompileTimeMachine<'tcx>>( + ecx: &mut InterpCx<'tcx, M>, + alloc_id: AllocId, + mutability: Mutability, + disambiguator: Option<&mut DisambiguatorState>, +) -> Result<impl Iterator<Item = CtfeProvenance> + 'tcx, InternError> { + trace!("intern_shallow {:?}", alloc_id); + // remove allocation + // FIXME(#120456) - is `swap_remove` correct? + let Some((kind, mut alloc)) = ecx.memory.alloc_map.swap_remove(&alloc_id) else { + return Err(InternError::DanglingPointer); + }; + + if let Err(err) = prepare_alloc(*ecx.tcx, kind, &mut alloc, mutability) { + // We want to error here, but we have to first put the + // allocation back into the `alloc_map` to keep things in a consistent state. + ecx.memory.alloc_map.insert(alloc_id, (kind, alloc)); + return Err(err); + } + // link the alloc id to the actual allocation let alloc = ecx.tcx.mk_const_alloc(alloc); if let Some(static_id) = ecx.machine.static_def_id() { @@ -166,6 +190,7 @@ pub enum InternError { BadMutablePointer, DanglingPointer, ConstAllocNotGlobal, + PartialPointer, } /// Intern `ret` and everything it references. @@ -221,13 +246,11 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx>>( let mut todo: Vec<_> = if is_static { // Do not steal the root allocation, we need it later to create the return value of `eval_static_initializer`. // But still change its mutability to match the requested one. - let alloc = ecx.memory.alloc_map.get_mut(&base_alloc_id).unwrap(); - alloc.1.mutability = base_mutability; - alloc.1.provenance().ptrs().iter().map(|&(_, prov)| prov).collect() + let (kind, alloc) = ecx.memory.alloc_map.get_mut(&base_alloc_id).unwrap(); + prepare_alloc(*ecx.tcx, *kind, alloc, base_mutability)?; + alloc.provenance().ptrs().iter().map(|&(_, prov)| prov).collect() } else { - intern_shallow(ecx, base_alloc_id, base_mutability, Some(&mut disambiguator)) - .unwrap() - .collect() + intern_shallow(ecx, base_alloc_id, base_mutability, Some(&mut disambiguator))?.collect() }; // We need to distinguish "has just been interned" from "was already in `tcx`", // so we track this in a separate set. @@ -235,7 +258,6 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx>>( // Whether we encountered a bad mutable pointer. // We want to first report "dangling" and then "mutable", so we need to delay reporting these // errors. - let mut result = Ok(()); let mut found_bad_mutable_ptr = false; // Keep interning as long as there are things to intern. @@ -310,20 +332,15 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx>>( // okay with losing some potential for immutability here. This can anyway only affect // `static mut`. just_interned.insert(alloc_id); - match intern_shallow(ecx, alloc_id, inner_mutability, Some(&mut disambiguator)) { - Ok(nested) => todo.extend(nested), - Err(err) => { - ecx.tcx.dcx().delayed_bug("error during const interning"); - result = Err(err); - } - } + let next = intern_shallow(ecx, alloc_id, inner_mutability, Some(&mut disambiguator))?; + todo.extend(next); } - if found_bad_mutable_ptr && result.is_ok() { + if found_bad_mutable_ptr { // We found a mutable pointer inside a const where inner allocations should be immutable, // and there was no other error. This should usually never happen! However, this can happen // in unleash-miri mode, so report it as a normal error then. if ecx.tcx.sess.opts.unstable_opts.unleash_the_miri_inside_of_you { - result = Err(InternError::BadMutablePointer); + return Err(InternError::BadMutablePointer); } else { span_bug!( ecx.tcx.span, @@ -331,7 +348,7 @@ pub fn intern_const_alloc_recursive<'tcx, M: CompileTimeMachine<'tcx>>( ); } } - result + Ok(()) } /// Intern `ret`. This function assumes that `ret` references no other allocation. |