bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Rollup merge of #128221 - calebzulawski:implied-target-features, r=Amanieu

Browse source 
Add implied target features to target_feature attribute

See [zulip](https://rust-lang.zulipchat.com/#narrow/stream/208962-t-libs.2Fstdarch/topic/Why.20would.20target-feature.20include.20implied.20features.3F) for some context.  Adds implied target features, e.g. `#[target_feature(enable = "avx2")]` acts like `#[target_feature(enable = "avx2,avx,sse4.2,sse4.1...")]`.  Fixes #128125, fixes #128426

The implied feature sets are taken from [the rust reference](https://doc.rust-lang.org/reference/attributes/codegen.html?highlight=target-fea#x86-or-x86_64), there are certainly more features and targets to add.

Please feel free to reassign this to whoever should review it.

r? ``@Amanieu``
This commit is contained in:
Matthias Krüger 2024-08-07 20:28:16 +02:00 • committed by GitHub
commit 904f5795a0
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
22 changed files with 594 additions and 485 deletions
Download patch file Download diff file Expand all files Collapse all files

41
compiler/rustc_codegen_ssa/src/target_features.rs
View file

@ -1,11 +1,12 @@
use rustc_ast::ast;
use rustc_attr::InstructionSetAttr;
use rustc_data_structures::fx::FxIndexSet;
use rustc_data_structures::unord::UnordMap;
use rustc_data_structures::unord::{UnordMap, UnordSet};
use rustc_errors::Applicability;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
use rustc_middle::bug;
use rustc_middle::middle::codegen_fn_attrs::TargetFeature;
use rustc_middle::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_session::parse::feature_err;
@ -18,7 +19,7 @@ pub fn from_target_feature(
tcx: TyCtxt<'_>,
attr: &ast::Attribute,
supported_target_features: &UnordMap<String, Option<Symbol>>,
target_features: &mut Vec<Symbol>,
target_features: &mut Vec<TargetFeature>,
) {
let Some(list) = attr.meta_item_list() else { return };
let bad_item = |span| {
@ -30,6 +31,7 @@ pub fn from_target_feature(
.emit();
};
let rust_features = tcx.features();
let mut added_target_features = Vec::new();
for item in list {
// Only `enable = ...` is accepted in the meta-item list.
if !item.has_name(sym::enable) {
@ -44,7 +46,7 @@ pub fn from_target_feature(
};
// We allow comma separation to enable multiple features.
target_features.extend(value.as_str().split(',').filter_map(|feature| {
added_target_features.extend(value.as_str().split(',').filter_map(|feature| {
let Some(feature_gate) = supported_target_features.get(feature) else {
let msg = format!("the feature named `{feature}` is not valid for this target");
let mut err = tcx.dcx().struct_span_err(item.span(), msg);
@ -98,13 +100,26 @@ pub fn from_target_feature(
}));
}
for (feature, requires) in tcx.sess.target.implicit_target_features() {
if target_features.iter().any(|f| f.as_str() == *feature)
&& !target_features.iter().any(|f| f.as_str() == *requires)
{
target_features.push(Symbol::intern(requires));
}
// Add explicit features
target_features.extend(
added_target_features.iter().copied().map(|name| TargetFeature { name, implied: false }),
);
// Add implied features
let mut implied_target_features = UnordSet::new();
for feature in added_target_features.iter() {
implied_target_features.extend(tcx.implied_target_features(*feature).clone());
}
for feature in added_target_features.iter() {
implied_target_features.remove(feature);
}
target_features.extend(
implied_target_features
.into_sorted_stable_ord()
.iter()
.copied()
.map(|name| TargetFeature { name, implied: true }),
)
}
/// Computes the set of target features used in a function for the purposes of
@ -113,7 +128,7 @@ fn asm_target_features(tcx: TyCtxt<'_>, did: DefId) -> &FxIndexSet<Symbol> {
let mut target_features = tcx.sess.unstable_target_features.clone();
if tcx.def_kind(did).has_codegen_attrs() {
let attrs = tcx.codegen_fn_attrs(did);
target_features.extend(&attrs.target_features);
target_features.extend(attrs.target_features.iter().map(|feature| feature.name));
match attrs.instruction_set {
None => {}
Some(InstructionSetAttr::ArmA32) => {
@ -158,10 +173,14 @@ pub(crate) fn provide(providers: &mut Providers) {
.target
.supported_target_features()
.iter()
.map(|&(a, b)| (a.to_string(), b.as_feature_name()))
.map(|&(a, b, _)| (a.to_string(), b.as_feature_name()))
.collect()
}
},
implied_target_features: |tcx, feature| {
UnordSet::from(tcx.sess.target.implied_target_features(std::iter::once(feature)))
.into_sorted_stable_ord()
},
asm_target_features,
..*providers
}