diff --git a/src/librustc_codegen_ssa/mir/block.rs b/src/librustc_codegen_ssa/mir/block.rs index 65f7e023fa226..e64c847db651b 100644 --- a/src/librustc_codegen_ssa/mir/block.rs +++ b/src/librustc_codegen_ssa/mir/block.rs @@ -238,6 +238,13 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { } } } + if self.fn_ty.ret.layout.abi.is_uninhabited() { + // Functions with uninhabited return values are marked `noreturn`, + // so we should make sure that we never actually do. + bx.abort(); + bx.unreachable(); + return; + } let llval = match self.fn_ty.ret.mode { PassMode::Ignore(IgnoreMode::Zst) | PassMode::Indirect(..) => { bx.ret_void(); diff --git a/src/test/codegen/noreturn-uninhabited.rs b/src/test/codegen/noreturn-uninhabited.rs new file mode 100644 index 0000000000000..1b65da9f2877a --- /dev/null +++ b/src/test/codegen/noreturn-uninhabited.rs @@ -0,0 +1,32 @@ +// compile-flags: -g -C no-prepopulate-passes +// ignore-tidy-linelength + +#![crate_type = "lib"] + +#[derive(Clone, Copy)] +pub enum EmptyEnum {} + +#[no_mangle] +pub fn empty(x: &EmptyEnum) -> EmptyEnum { + // CHECK: @empty({{.*}}) unnamed_addr #0 + // CHECK-NOT: ret void + // CHECK: call void @llvm.trap() + // CHECK: unreachable + *x +} + +pub struct Foo(String, EmptyEnum); + +#[no_mangle] +pub fn foo(x: String, y: &EmptyEnum) -> Foo { + // CHECK: @foo({{.*}}) unnamed_addr #0 + // CHECK-NOT: ret %Foo + // CHECK: call void @llvm.trap() + // CHECK: unreachable + Foo(x, *y) +} + +// CHECK: attributes #0 = {{{.*}} noreturn {{.*}}} + +// CHECK: DISubprogram(name: "empty", {{.*}} DIFlagNoReturn +// CHECK: DISubprogram(name: "foo", {{.*}} DIFlagNoReturn