diff --git a/tests/run-make/avr-rjmp-offset/avr-rjmp-offsets.rs b/tests/run-make/avr-rjmp-offset/avr-rjmp-offsets.rs new file mode 100644 index 00000000000..2f97fc1ed95 --- /dev/null +++ b/tests/run-make/avr-rjmp-offset/avr-rjmp-offsets.rs @@ -0,0 +1,47 @@ +//! This test case is a `#![no_core]`-version of the MVCE presented in #129301. +//! +//! The function [`delay()`] is removed, as it is not necessary to trigger the +//! wrong behavior and would require some additional lang items. +#![feature(no_core, lang_items, intrinsics, rustc_attrs)] +#![no_core] +#![no_main] +#![allow(internal_features)] + +use minicore::ptr; + +#[no_mangle] +pub fn main() -> ! { + let port_b = 0x25 as *mut u8; // the I/O-address of PORTB + + // a simple loop with some trivial instructions within. This loop label has + // to be placed correctly before the `ptr::write_volatile()` (some LLVM ver- + // sions did place it after the first loop instruction, causing unsoundness) + loop { + unsafe { ptr::write_volatile(port_b, 1) }; + unsafe { ptr::write_volatile(port_b, 2) }; + } +} + +// FIXME: replace with proper minicore once available (#130693) +mod minicore { + #[lang = "sized"] + pub trait Sized {} + + #[lang = "copy"] + pub trait Copy {} + impl Copy for u32 {} + impl Copy for &u32 {} + impl Copy for *mut T {} + + pub mod ptr { + #[inline] + #[rustc_diagnostic_item = "ptr_write_volatile"] + pub unsafe fn write_volatile(dst: *mut T, src: T) { + extern "rust-intrinsic" { + #[rustc_nounwind] + pub fn volatile_store(dst: *mut T, val: T); + } + unsafe { volatile_store(dst, src) }; + } + } +} diff --git a/tests/run-make/avr-rjmp-offset/rmake.rs b/tests/run-make/avr-rjmp-offset/rmake.rs new file mode 100644 index 00000000000..89cbca309be --- /dev/null +++ b/tests/run-make/avr-rjmp-offset/rmake.rs @@ -0,0 +1,60 @@ +//@ needs-llvm-components: avr +//@ needs-rust-lld +//! Regression test for #129301/llvm-project#106722 within `rustc`. +//! +//! Some LLVM-versions had wrong offsets in the local labels, causing the first +//! loop instruction to be missed. This test therefore contains a simple loop +//! with trivial instructions in it, to see, where the label is placed. +//! +//! This must be a `rmake`-test and cannot be a `tests/assembly`-test, since the +//! wrong output is only produced with direct assembly generation, but not when +//! "emit-asm" is used, as described in the issue description of #129301: +//! https://github.com/rust-lang/rust/issues/129301#issue-2475070770 +use run_make_support::{llvm_objdump, rustc}; + +fn main() { + rustc() + .input("avr-rjmp-offsets.rs") + .opt_level("s") + .panic("abort") + .target("avr-unknown-gnu-atmega328") + // normally one links with `avr-gcc`, but this is not available in CI, + // hence this test diverges from the default behavior to enable linking + // at all, which is necessary for the test (to resolve the labels). To + // not depend on a special linker script, the main-function is marked as + // the entry function, causing the linker to not remove it. + .linker("rust-lld") + .link_arg("--entry=main") + .output("compiled") + .run(); + + let disassembly = llvm_objdump().disassemble().input("compiled").run().stdout_utf8(); + + // search for the following instruction sequence: + // ```disassembly + // 00000080
: + // 80: 81 e0 ldi r24, 0x1 + // 82: 92 e0 ldi r25, 0x2 + // 84: 85 b9 out 0x5, r24 + // 86: 95 b9 out 0x5, r25 + // 88: fd cf rjmp .-6 + // ``` + // This matches on all instructions, since the size of the instructions be- + // fore the relative jump has an impact on the label offset. Old versions + // of the Rust compiler did produce a label `rjmp .-4` (misses the first + // instruction in the loop). + assert!(disassembly.contains("
"), "no main function in output"); + disassembly + .trim() + .lines() + .skip_while(|&line| !line.contains("
")) + .inspect(|line| println!("{line}")) + .skip(1) + .zip(["ldi\t", "ldi\t", "out\t", "out\t", "rjmp\t.-6"]) + .for_each(|(line, expected_instruction)| { + assert!( + line.contains(expected_instruction), + "expected instruction `{expected_instruction}`, got `{line}`" + ); + }); +}