diff options
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/block.rs | 28 | ||||
| -rw-r--r-- | tests/codegen/uninhabited-transparent-return-abi.rs | 44 | ||||
| -rw-r--r-- | tests/ui/uninhabited/uninhabited-transparent-return-abi.rs | 33 |
3 files changed, 84 insertions, 21 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/block.rs b/compiler/rustc_codegen_ssa/src/mir/block.rs index 0620f08fc73..49074996174 100644 --- a/compiler/rustc_codegen_ssa/src/mir/block.rs +++ b/compiler/rustc_codegen_ssa/src/mir/block.rs @@ -4,9 +4,7 @@ use rustc_abi::{BackendRepr, ExternAbi, HasDataLayout, Reg, WrappingRange}; use rustc_ast as ast; use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece}; use rustc_hir::lang_items::LangItem; -use rustc_middle::mir::{ - self, AssertKind, BasicBlock, InlineAsmMacro, SwitchTargets, UnwindTerminateReason, -}; +use rustc_middle::mir::{self, AssertKind, InlineAsmMacro, SwitchTargets, UnwindTerminateReason}; use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, ValidityRequirement}; use rustc_middle::ty::print::{with_no_trimmed_paths, with_no_visible_paths}; use rustc_middle::ty::{self, Instance, Ty}; @@ -942,7 +940,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { &fn_abi.ret, &mut llargs, Some(intrinsic), - target, ); let dest = match ret_dest { _ if fn_abi.ret.is_indirect() => llargs[0], @@ -998,19 +995,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { }; let mut llargs = Vec::with_capacity(arg_count); - let destination = target.as_ref().map(|&target| { - ( - self.make_return_dest( - bx, - destination, - &fn_abi.ret, - &mut llargs, - None, - Some(target), - ), - target, - ) - }); + + // We still need to call `make_return_dest` even if there's no `target`, since + // `fn_abi.ret` could be `PassMode::Indirect`, even if it is uninhabited, + // and `make_return_dest` adds the return-place indirect pointer to `llargs`. + let return_dest = self.make_return_dest(bx, destination, &fn_abi.ret, &mut llargs, None); + let destination = target.map(|target| (return_dest, target)); // Split the rust-call tupled arguments off. let (first_args, untuple) = if abi == ExternAbi::RustCall && !args.is_empty() { @@ -1813,11 +1803,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { fn_ret: &ArgAbi<'tcx, Ty<'tcx>>, llargs: &mut Vec<Bx::Value>, intrinsic: Option<ty::IntrinsicDef>, - target: Option<BasicBlock>, ) -> ReturnDest<'tcx, Bx::Value> { - if target.is_none() { - return ReturnDest::Nothing; - } // If the return is ignored, we can just return a do-nothing `ReturnDest`. if fn_ret.is_ignore() { return ReturnDest::Nothing; diff --git a/tests/codegen/uninhabited-transparent-return-abi.rs b/tests/codegen/uninhabited-transparent-return-abi.rs new file mode 100644 index 00000000000..6e8b1683163 --- /dev/null +++ b/tests/codegen/uninhabited-transparent-return-abi.rs @@ -0,0 +1,44 @@ +//@ compile-flags: -Copt-level=3 + +// See https://github.com/rust-lang/rust/issues/135802 + +#![crate_type = "lib"] + +enum Void {} + +// Should be ABI-compatible with T, but wasn't prior to the PR adding this test. +#[repr(transparent)] +struct NoReturn<T>(T, Void); + +// Returned by invisible reference (in most ABIs) +#[allow(dead_code)] +struct Large(u64, u64, u64); + +extern "Rust" { + fn opaque() -> NoReturn<Large>; + fn opaque_with_arg(rsi: u32) -> NoReturn<Large>; +} + +// CHECK-LABEL: @test_uninhabited_ret_by_ref +#[no_mangle] +pub fn test_uninhabited_ret_by_ref() { + // CHECK: %_1 = alloca [24 x i8], align {{8|4}} + // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 24, ptr nonnull %_1) + // CHECK-NEXT: call void @opaque(ptr noalias nocapture noundef nonnull sret([24 x i8]) align {{8|4}} dereferenceable(24) %_1) #2 + // CHECK-NEXT: unreachable + unsafe { + opaque(); + } +} + +// CHECK-LABEL: @test_uninhabited_ret_by_ref_with_arg +#[no_mangle] +pub fn test_uninhabited_ret_by_ref_with_arg(rsi: u32) { + // CHECK: %_2 = alloca [24 x i8], align {{8|4}} + // CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 24, ptr nonnull %_2) + // CHECK-NEXT: call void @opaque_with_arg(ptr noalias nocapture noundef nonnull sret([24 x i8]) align {{8|4}} dereferenceable(24) %_2, i32 noundef %rsi) #2 + // CHECK-NEXT: unreachable + unsafe { + opaque_with_arg(rsi); + } +} diff --git a/tests/ui/uninhabited/uninhabited-transparent-return-abi.rs b/tests/ui/uninhabited/uninhabited-transparent-return-abi.rs new file mode 100644 index 00000000000..2c2788a3e56 --- /dev/null +++ b/tests/ui/uninhabited/uninhabited-transparent-return-abi.rs @@ -0,0 +1,33 @@ +//@ run-pass +//@ needs-unwind +// See https://github.com/rust-lang/rust/issues/135802 + +enum Void {} + +// Should be ABI-compatible with T, but wasn't prior to the PR adding this test. +#[repr(transparent)] +struct NoReturn<T>(T, Void); + +// Returned by invisible reference (in most ABIs) +#[allow(dead_code)] +struct Large(u64, u64, u64); + +// Prior to the PR adding this test, this function had a different ABI than +// `fn() -> Large` (on `x86_64-unknown-linux-gnu` at least), so calling it as `fn() -> Large` +// would pass the return place pointer in rdi and `correct` in rsi, but the function +// would expect `correct` in rdi. +fn never(correct: &mut bool) -> NoReturn<Large> { + *correct = true; + panic!("catch this") +} + +fn main() { + let mut correct = false; + let never: fn(&mut bool) -> NoReturn<Large> = never; + // Safety: `NoReturn<Large>` is a `repr(transparent)` wrapper around `Large`, + // so they should be ABI-compatible. + let never: fn(&mut bool) -> Large = unsafe { std::mem::transmute(never) }; + let result = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| never(&mut correct))); + assert!(result.is_err(), "function should have panicked"); + assert!(correct, "function should have stored `true` into `correct`"); +} |