From cb5dc7852ef7082efb66461985b20df40c80cd77 Mon Sep 17 00:00:00 2001 From: Jamie Cunliffe Date: Mon, 27 Oct 2025 13:49:23 +0000 Subject: [PATCH 1/3] Broken test to show alwaysinline attribute not being applied --- tests/codegen-llvm/inline-always-callsite.rs | 37 ++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 tests/codegen-llvm/inline-always-callsite.rs diff --git a/tests/codegen-llvm/inline-always-callsite.rs b/tests/codegen-llvm/inline-always-callsite.rs new file mode 100644 index 0000000000000..3000ceb1bbc4f --- /dev/null +++ b/tests/codegen-llvm/inline-always-callsite.rs @@ -0,0 +1,37 @@ +//@ add-core-stubs +//@ compile-flags: --target aarch64-unknown-linux-gnu -Zinline-mir=no -C no-prepopulate-passes +//@ needs-llvm-components: aarch64 + +#![crate_type = "lib"] +#![feature(no_core, lang_items, target_feature_inline_always)] +#![no_core] + +extern crate minicore; +use minicore::*; + +#[inline(always)] +#[target_feature(enable = "neon")] +#[no_mangle] +pub fn single_target_feature() -> i32 { + 42 +} + +#[inline(always)] +#[target_feature(enable = "neon,i8mm")] +#[no_mangle] +// CHECK: define noundef i32 @multiple_target_features() unnamed_addr #1 { +pub fn multiple_target_features() -> i32 { + // CHECK: %_0 = call noundef i32 @single_target_feature() #3 + single_target_feature() +} + +#[no_mangle] +// CHECK: define noundef i32 @inherits_from_global() unnamed_addr #2 { +pub fn inherits_from_global() -> i32 { + unsafe { + // CHECK: %_0 = call noundef i32 @single_target_feature() #3 + single_target_feature() + } +} + +// CHECK: attributes #3 = { nounwind } From c5c6ee56b683ff7c2ded12e9cc022779a310b667 Mon Sep 17 00:00:00 2001 From: Jamie Cunliffe Date: Mon, 27 Oct 2025 14:09:17 +0000 Subject: [PATCH 2/3] Fix issue with callsite inline attribute not being applied sometimes. If the calling function had more target features enabled than the callee than the attribute wasn't being applied as the arguments for the check had been swapped round. Also includes target features that are part of the global set as the warning was checking those but when adding the attribute they were not checked. Add a codegen-llvm test to check that the attribute is actually applied as previously only the warning was being checked. --- compiler/rustc_codegen_llvm/src/builder.rs | 10 +++++++--- tests/codegen-llvm/inline-always-callsite.rs | 4 ++-- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs index d441cd119a747..f7f911b654761 100644 --- a/compiler/rustc_codegen_llvm/src/builder.rs +++ b/compiler/rustc_codegen_llvm/src/builder.rs @@ -16,7 +16,7 @@ use rustc_codegen_ssa::mir::place::PlaceRef; use rustc_codegen_ssa::traits::*; use rustc_data_structures::small_c_str::SmallCStr; use rustc_hir::def_id::DefId; -use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrs; +use rustc_middle::middle::codegen_fn_attrs::{CodegenFnAttrs, TargetFeature, TargetFeatureKind}; use rustc_middle::ty::layout::{ FnAbiError, FnAbiOfHelpers, FnAbiRequest, HasTypingEnv, LayoutError, LayoutOfHelpers, TyAndLayout, @@ -1417,14 +1417,18 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> { // Attributes on the function definition being called let fn_defn_attrs = self.cx.tcx.codegen_fn_attrs(instance.def_id()); if let Some(fn_call_attrs) = fn_call_attrs - && !fn_call_attrs.target_features.is_empty() // If there is an inline attribute and a target feature that matches // we will add the attribute to the callsite otherwise we'll omit // this and not add the attribute to prevent soundness issues. && let Some(inlining_rule) = attributes::inline_attr(&self.cx, self.cx.tcx, instance) && self.cx.tcx.is_target_feature_call_safe( - &fn_call_attrs.target_features, &fn_defn_attrs.target_features, + &fn_call_attrs.target_features.iter().cloned().chain( + self.cx.tcx.sess.target_features.iter().map(|feat| TargetFeature { + name: *feat, + kind: TargetFeatureKind::Implied, + }) + ).collect::>(), ) { attributes::apply_to_callsite( diff --git a/tests/codegen-llvm/inline-always-callsite.rs b/tests/codegen-llvm/inline-always-callsite.rs index 3000ceb1bbc4f..229c85049d782 100644 --- a/tests/codegen-llvm/inline-always-callsite.rs +++ b/tests/codegen-llvm/inline-always-callsite.rs @@ -1,4 +1,4 @@ -//@ add-core-stubs +//@ add-minicore //@ compile-flags: --target aarch64-unknown-linux-gnu -Zinline-mir=no -C no-prepopulate-passes //@ needs-llvm-components: aarch64 @@ -34,4 +34,4 @@ pub fn inherits_from_global() -> i32 { } } -// CHECK: attributes #3 = { nounwind } +// CHECK: attributes #3 = { alwaysinline nounwind } From e2c5c18166e6eaa7b5f9af509dcf1376195aa49d Mon Sep 17 00:00:00 2001 From: Jamie Cunliffe Date: Mon, 27 Oct 2025 15:53:06 +0000 Subject: [PATCH 3/3] Review comments --- compiler/rustc_middle/src/ty/context.rs | 2 ++ tests/codegen-llvm/inline-always-callsite.rs | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs index a00eaef20c083..7182747386933 100644 --- a/compiler/rustc_middle/src/ty/context.rs +++ b/compiler/rustc_middle/src/ty/context.rs @@ -2088,6 +2088,8 @@ impl<'tcx> TyCtxt<'tcx> { self.sess.dcx() } + /// Checks to see if the caller (`body_features`) has all the features required by the callee + /// (`callee_features`). pub fn is_target_feature_call_safe( self, callee_features: &[TargetFeature], diff --git a/tests/codegen-llvm/inline-always-callsite.rs b/tests/codegen-llvm/inline-always-callsite.rs index 229c85049d782..2821c606aa0ee 100644 --- a/tests/codegen-llvm/inline-always-callsite.rs +++ b/tests/codegen-llvm/inline-always-callsite.rs @@ -34,4 +34,8 @@ pub fn inherits_from_global() -> i32 { } } +// Attribute #3 requires the alwaysinline attribute, the alwaysinline attribute is not emitted on a +// function definition when target features are present, rather it will be moved onto the function +// call, if the features match up. +// // CHECK: attributes #3 = { alwaysinline nounwind }