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Rollup merge of #141045 - dpaoliello:noarmhazard, r=jieyouxu

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[win][arm64] Remove 'Arm64 Hazard' undocumented MSVC option and instead disable problematic test

PR #140758 added the undocumented `/arm64hazardfree` MSVC linker flag to work around a test failure where LLVM generated code that would trip a hazard in an outdated ARM processor.

Adding this flag caused issues with LLD, as it doesn't recognize it.

Rethinking the issue, using the undocumented flag seems like the incorrect solution: there's no guarantee that the flag won't be removed in the future, or change its meaning.

Instead, I've disabled the problematic test for Arm64 Windows and have filed a bug with the MSVC team to have the check removed: <https://developercommunity.microsoft.com/t/Remove-checking-for-and-fixing-Cortex-A/10905134>

This PR supersedes #140977

r? ```@jieyouxu```
This commit is contained in:
León Orell Valerian Liehr
2025-05-18 11:03:46 +02:00
committed by GitHub
parent eb21b252c6 6128fca0b0
commit e323c64fa4
2 changed files with 8 additions and 6 deletions
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7
compiler/rustc_target/src/spec/targets/aarch64_pc_windows_msvc.rs
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@@ -1,4 +1,4 @@
use crate::spec::{FramePointer, LinkerFlavor, Lld, Target, TargetMetadata, base};
use crate::spec::{FramePointer, Target, TargetMetadata, base};
pub(crate) fn target() -> Target {
let mut base = base::windows_msvc::opts();
@@ -11,11 +11,6 @@ pub(crate) fn target() -> Target {
// and other services. It must point to the previous {x29, x30} pair on the stack."
base.frame_pointer = FramePointer::NonLeaf;
// MSVC emits a warning about code that may trip "Cortex-A53 MPCore processor bug #843419" (see
// https://developer.arm.com/documentation/epm048406/latest) which is sometimes emitted by LLVM.
// Since Arm64 Windows 10+ isn't supported on that processor, it's safe to disable the warning.
base.add_pre_link_args(LinkerFlavor::Msvc(Lld::No), &["/arm64hazardfree"]);
Target {
llvm_target: "aarch64-pc-windows-msvc".into(),
metadata: TargetMetadata {

7
tests/run-make/llvm-location-discriminator-limit-dummy-span/rmake.rs
View File

@@ -11,6 +11,13 @@
//@ needs-dynamic-linking
//@ only-nightly (requires unstable rustc flag)
// This test trips a check in the MSVC linker for an outdated processor:
// "LNK1322: cannot avoid potential ARM hazard (Cortex-A53 MPCore processor bug #843419)"
// Until MSVC removes this check:
// https://developercommunity.microsoft.com/t/Remove-checking-for-and-fixing-Cortex-A/10905134
// we'll need to disable this test on Arm64 Windows.
//@ ignore-aarch64-pc-windows-msvc
#![deny(warnings)]
use run_make_support::{dynamic_lib_name, rfs, rust_lib_name, rustc};