diff options
| -rw-r--r-- | src/librustc_mir/interpret/intern.rs | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/src/librustc_mir/interpret/intern.rs b/src/librustc_mir/interpret/intern.rs index 8ff78ffb5ba..4c7dab338ab 100644 --- a/src/librustc_mir/interpret/intern.rs +++ b/src/librustc_mir/interpret/intern.rs @@ -351,6 +351,9 @@ pub fn intern_const_alloc_recursive<M: CompileTimeMachine<'mir, 'tcx>>( InternKind::Static(hir::Mutability::Mut) => {} // Once we get heap allocations we need to revisit whether immutable statics can // refer to mutable (e.g. via interior mutability) allocations. + // Note: this is never the base value of the static, we can only get here for + // pointers encountered inside the base allocation, and then only for ones not at + // reference type, as that is checked by the type based main interner. InternKind::Static(hir::Mutability::Not) => { alloc.mutability = Mutability::Not; } @@ -385,6 +388,17 @@ pub fn intern_const_alloc_recursive<M: CompileTimeMachine<'mir, 'tcx>>( // dangling pointer throw_unsup!(ValidationFailure("encountered dangling pointer in final constant".into())) } else if let Some(_) = ecx.tcx.alloc_map.lock().get(alloc_id) { + // If we encounter an `AllocId` that points to a mutable `Allocation`, + // (directly or via relocations in its `Allocation`), we should panic, + // the static rules should prevent this. + // We may hit an `AllocId` that belongs to an already interned static, + // and are thus not interning any further. + // But since we are also checking things during interning, + // we should probably continue doing those checks no matter what we encounter. + + // E.g. this should be unreachable for `InternKind::Promoted` except for allocations + // created for string and byte string literals. + // FIXME: check if the allocation is ok as per the interning rules as if we interned // it right here. } else { |