From 5a20bac6b3ff61acc3cd68bed0eb3fa598181f17 Mon Sep 17 00:00:00 2001 From: Ralf Jung Date: Sat, 2 Dec 2023 22:25:14 +0100 Subject: more targeted errors when extern types end up in places they should not --- compiler/rustc_codegen_llvm/src/builder.rs | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'compiler/rustc_codegen_llvm/src') diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs index 7b259055d40..acd85dd9a2d 100644 --- a/compiler/rustc_codegen_llvm/src/builder.rs +++ b/compiler/rustc_codegen_llvm/src/builder.rs @@ -489,6 +489,15 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> { #[instrument(level = "trace", skip(self))] fn load_operand(&mut self, place: PlaceRef<'tcx, &'ll Value>) -> OperandRef<'tcx, &'ll Value> { + if place.layout.is_unsized() { + let tail = self.tcx.struct_tail_with_normalize(place.layout.ty, |ty| ty, || {}); + if matches!(tail.kind(), ty::Foreign(..)) { + // Unsized locals and, at least conceptually, even unsized arguments must be copied + // around, which requires dynamically determining their size. Therefore, we cannot + // allow `extern` types here. Consult t-opsem before removing this check. + panic!("unsized locals must not be `extern` types"); + } + } assert_eq!(place.llextra.is_some(), place.layout.is_unsized()); if place.layout.is_zst() { -- cgit 1.4.1-3-g733a5