rustc: Tweak #[target_feature] syntax

src/librustc/dep_graph/dep_node.rs

@@ -635,6 +635,10 @@ define_dep_nodes!( <'tcx>
     [] Null,
 
     [] SubstituteNormalizeAndTestPredicates { key: (DefId, &'tcx Substs<'tcx>) },
+
+    [input] TargetFeaturesWhitelist,
+    [] TargetFeaturesEnabled(DefId),
+
 );
 
 trait DepNodeParams<'a, 'gcx: 'tcx + 'a, 'tcx: 'a> : fmt::Debug {

src/librustc/hir/check_attr.rs

@@ -14,11 +14,10 @@
 //! conflicts between multiple such attributes attached to the same
 //! item.
 
-use session::Session;
+use ty::TyCtxt;
 
-use syntax::ast;
-use syntax::visit;
-use syntax::visit::Visitor;
+use hir;
+use hir::intravisit::{self, Visitor, NestedVisitorMap};
 
 #[derive(Copy, Clone, PartialEq)]
 enum Target {
@@ -30,45 +29,51 @@ enum Target {
 }
 
 impl Target {
-    fn from_item(item: &ast::Item) -> Target {
+    fn from_item(item: &hir::Item) -> Target {
         match item.node {
-            ast::ItemKind::Fn(..) => Target::Fn,
-            ast::ItemKind::Struct(..) => Target::Struct,
-            ast::ItemKind::Union(..) => Target::Union,
-            ast::ItemKind::Enum(..) => Target::Enum,
+            hir::ItemFn(..) => Target::Fn,
+            hir::ItemStruct(..) => Target::Struct,
+            hir::ItemUnion(..) => Target::Union,
+            hir::ItemEnum(..) => Target::Enum,
             _ => Target::Other,
         }
     }
 }
 
-struct CheckAttrVisitor<'a> {
-    sess: &'a Session,
+struct CheckAttrVisitor<'a, 'tcx: 'a> {
+    tcx: TyCtxt<'a, 'tcx, 'tcx>,
 }
 
-impl<'a> CheckAttrVisitor<'a> {
+impl<'a, 'tcx> CheckAttrVisitor<'a, 'tcx> {
     /// Check any attribute.
-    fn check_attributes(&self, item: &ast::Item, target: Target) {
+    fn check_attributes(&self, item: &hir::Item, target: Target) {
+        self.tcx.target_features_enabled(self.tcx.hir.local_def_id(item.id));
+
         for attr in &item.attrs {
             if let Some(name) = attr.name() {
                 if name == "inline" {
                     self.check_inline(attr, item, target)
                 }
             }
         }
+
         self.check_repr(item, target);
     }
 
     /// Check if an `#[inline]` is applied to a function.
-    fn check_inline(&self, attr: &ast::Attribute, item: &ast::Item, target: Target) {
+    fn check_inline(&self, attr: &hir::Attribute, item: &hir::Item, target: Target) {
         if target != Target::Fn {
-            struct_span_err!(self.sess, attr.span, E0518, "attribute should be applied to function")
+            struct_span_err!(self.tcx.sess,
+                             attr.span,
+                             E0518,
+                             "attribute should be applied to function")
                 .span_label(item.span, "not a function")
                 .emit();
         }
     }
 
     /// Check if the `#[repr]` attributes on `item` are valid.
-    fn check_repr(&self, item: &ast::Item, target: Target) {
+    fn check_repr(&self, item: &hir::Item, target: Target) {
         // Extract the names of all repr hints, e.g., [foo, bar, align] for:
         // ```
         // #[repr(foo)]
@@ -144,7 +149,7 @@ impl<'a> CheckAttrVisitor<'a> {
                 }
                 _ => continue,
             };
-            struct_span_err!(self.sess, hint.span, E0517,
+            struct_span_err!(self.tcx.sess, hint.span, E0517,
                              "attribute should be applied to {}", allowed_targets)
                 .span_label(item.span, format!("not {} {}", article, allowed_targets))
                 .emit();
@@ -154,32 +159,37 @@ impl<'a> CheckAttrVisitor<'a> {
         if (int_reprs > 1)
            || (is_simd && is_c)
            || (int_reprs == 1 && is_c && is_c_like_enum(item)) {
-            // Just point at all repr hints. This is not ideal, but tracking precisely which ones
-            // are at fault is a huge hassle.
+            // Just point at all repr hints. This is not ideal, but tracking
+            // precisely which ones are at fault is a huge hassle.
             let spans: Vec<_> = hints.iter().map(|hint| hint.span).collect();
-            span_warn!(self.sess, spans, E0566,
+            span_warn!(self.tcx.sess, spans, E0566,
                        "conflicting representation hints");
         }
     }
 }
 
-impl<'a> Visitor<'a> for CheckAttrVisitor<'a> {
-    fn visit_item(&mut self, item: &'a ast::Item) {
+impl<'a, 'tcx> Visitor<'tcx> for CheckAttrVisitor<'a, 'tcx> {
+    fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
+        NestedVisitorMap::None
+    }
+
+    fn visit_item(&mut self, item: &'tcx hir::Item) {
         let target = Target::from_item(item);
         self.check_attributes(item, target);
-        visit::walk_item(self, item);
+        intravisit::walk_item(self, item);
     }
 }
 
-pub fn check_crate(sess: &Session, krate: &ast::Crate) {
-    visit::walk_crate(&mut CheckAttrVisitor { sess: sess }, krate);
+pub fn check_crate<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) {
+    let mut checker = CheckAttrVisitor { tcx };
+    tcx.hir.krate().visit_all_item_likes(&mut checker.as_deep_visitor());
 }
 
-fn is_c_like_enum(item: &ast::Item) -> bool {
-    if let ast::ItemKind::Enum(ref def, _) = item.node {
+fn is_c_like_enum(item: &hir::Item) -> bool {
+    if let hir::ItemEnum(ref def, _) = item.node {
         for variant in &def.variants {
             match variant.node.data {
-                ast::VariantData::Unit(_) => { /* continue */ }
+                hir::VariantData::Unit(_) => { /* continue */ }
                 _ => { return false; }
             }
         }

src/librustc/ty/maps/config.rs

@@ -631,6 +631,12 @@ impl<'tcx> QueryDescription<'tcx> for queries::substitute_normalize_and_test_pre
     }
 }
 
+impl<'tcx> QueryDescription<'tcx> for queries::target_features_whitelist<'tcx> {
+    fn describe(_tcx: TyCtxt, _: CrateNum) -> String {
+        format!("looking up the whitelist of target features")
+    }
+}
+
 macro_rules! impl_disk_cacheable_query(
     ($query_name:ident, |$key:tt| $cond:expr) => {
         impl<'tcx> QueryDescription<'tcx> for queries::$query_name<'tcx> {

src/librustc/ty/maps/mod.rs

@@ -363,6 +363,11 @@ define_maps! { <'tcx>
 
     [] fn substitute_normalize_and_test_predicates:
         substitute_normalize_and_test_predicates_node((DefId, &'tcx Substs<'tcx>)) -> bool,
+
+    [] fn target_features_whitelist:
+        target_features_whitelist_node(CrateNum) -> Rc<FxHashSet<String>>,
+    [] fn target_features_enabled: TargetFeaturesEnabled(DefId) -> Rc<Vec<String>>,
+
 }
 
 //////////////////////////////////////////////////////////////////////
@@ -508,3 +513,7 @@ fn substitute_normalize_and_test_predicates_node<'tcx>(key: (DefId, &'tcx Substs
                                             -> DepConstructor<'tcx> {
     DepConstructor::SubstituteNormalizeAndTestPredicates { key }
 }
+
+fn target_features_whitelist_node<'tcx>(_: CrateNum) -> DepConstructor<'tcx> {
+    DepConstructor::TargetFeaturesWhitelist
+}

src/librustc/ty/maps/plumbing.rs

@@ -918,6 +918,9 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         }
         DepKind::IsTranslatedFunction => { force!(is_translated_function, def_id!()); }
         DepKind::OutputFilenames => { force!(output_filenames, LOCAL_CRATE); }
+
+        DepKind::TargetFeaturesWhitelist => { force!(target_features_whitelist, LOCAL_CRATE); }
+        DepKind::TargetFeaturesEnabled => { force!(target_features_enabled, def_id!()); }
     }
 
     true

src/librustc_driver/driver.rs

@@ -210,10 +210,6 @@ pub fn compile_input(sess: &Session,
                                     Ok(()));
         }
 
-        time(sess.time_passes(), "attribute checking", || {
-            hir::check_attr::check_crate(sess, &expanded_crate);
-        });
-
         let opt_crate = if control.keep_ast {
             Some(&expanded_crate)
         } else {
@@ -1038,6 +1034,10 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(control: &CompileController,
         // tcx available.
         rustc_incremental::dep_graph_tcx_init(tcx);
 
+        time(sess.time_passes(), "attribute checking", || {
+            hir::check_attr::check_crate(tcx)
+        });
+
         time(time_passes,
              "stability checking",
              || stability::check_unstable_api_usage(tcx));

src/librustc_trans/attributes.rs

@@ -10,11 +10,18 @@
 //! Set and unset common attributes on LLVM values.
 
 use std::ffi::{CStr, CString};
+use std::rc::Rc;
 
+use rustc::hir::Unsafety;
+use rustc::hir::def_id::{DefId, LOCAL_CRATE};
 use rustc::session::config::Sanitizer;
+use rustc::ty::TyCtxt;
+use rustc::ty::maps::Providers;
+use rustc_data_structures::fx::FxHashSet;
 
 use llvm::{self, Attribute, ValueRef};
 use llvm::AttributePlace::Function;
+use llvm_util;
 pub use syntax::attr::{self, InlineAttr};
 use syntax::ast;
 use context::CrateContext;
@@ -94,23 +101,16 @@ pub fn set_probestack(ccx: &CrateContext, llfn: ValueRef) {
 
 /// Composite function which sets LLVM attributes for function depending on its AST (#[attribute])
 /// attributes.
-pub fn from_fn_attrs(ccx: &CrateContext, attrs: &[ast::Attribute], llfn: ValueRef) {
+pub fn from_fn_attrs(ccx: &CrateContext, llfn: ValueRef, id: DefId) {
     use syntax::attr::*;
-    inline(llfn, find_inline_attr(Some(ccx.sess().diagnostic()), attrs));
+    let attrs = ccx.tcx().get_attrs(id);
+    inline(llfn, find_inline_attr(Some(ccx.sess().diagnostic()), &attrs));
 
     set_frame_pointer_elimination(ccx, llfn);
     set_probestack(ccx, llfn);
-    let mut target_features = vec![];
-    for attr in attrs {
-        if attr.check_name("target_feature") {
-            if let Some(val) = attr.value_str() {
-                for feat in val.as_str().split(",").map(|f| f.trim()) {
-                    if !feat.is_empty() && !feat.contains('\0') {
-                        target_features.push(feat.to_string());
-                    }
-                }
-            }
-        } else if attr.check_name("cold") {
+
+    for attr in attrs.iter() {
+        if attr.check_name("cold") {
             Attribute::Cold.apply_llfn(Function, llfn);
         } else if attr.check_name("naked") {
             naked(llfn, true);
@@ -123,6 +123,8 @@ pub fn from_fn_attrs(ccx: &CrateContext, attrs: &[ast::Attribute], llfn: ValueRe
             unwind(llfn, false);
         }
     }
+
+    let target_features = ccx.tcx().target_features_enabled(id);
     if !target_features.is_empty() {
         let val = CString::new(target_features.join(",")).unwrap();
         llvm::AddFunctionAttrStringValue(
@@ -134,3 +136,97 @@ pub fn from_fn_attrs(ccx: &CrateContext, attrs: &[ast::Attribute], llfn: ValueRe
 fn cstr(s: &'static str) -> &CStr {
     CStr::from_bytes_with_nul(s.as_bytes()).expect("null-terminated string")
 }
+
+pub fn provide(providers: &mut Providers) {
+    providers.target_features_whitelist = |tcx, cnum| {
+        assert_eq!(cnum, LOCAL_CRATE);
+        Rc::new(llvm_util::target_feature_whitelist(tcx.sess)
+            .iter()
+            .map(|c| c.to_str().unwrap().to_string())
+            .collect())
+    };
+
+    providers.target_features_enabled = |tcx, id| {
+        let whitelist = tcx.target_features_whitelist(LOCAL_CRATE);
+        let mut target_features = Vec::new();
+        for attr in tcx.get_attrs(id).iter() {
+            if !attr.check_name("target_feature") {
+                continue
+            }
+            if let Some(val) = attr.value_str() {
+                for feat in val.as_str().split(",").map(|f| f.trim()) {
+                    if !feat.is_empty() && !feat.contains('\0') {
+                        target_features.push(feat.to_string());
+                    }
+                }
+                let msg = "#[target_feature = \"..\"] is deprecated and will \
+                           eventually be removed, use \
+                           #[target_feature(enable = \"..\")] instead";
+                tcx.sess.span_warn(attr.span, &msg);
+                continue
+            }
+
+            if tcx.fn_sig(id).unsafety() == Unsafety::Normal {
+                let msg = "#[target_feature(..)] can only be applied to \
+                           `unsafe` function";
+                tcx.sess.span_err(attr.span, msg);
+            }
+            from_target_feature(tcx, attr, &whitelist, &mut target_features);
+        }
+        Rc::new(target_features)
+    };
+}
+
+fn from_target_feature(
+    tcx: TyCtxt,
+    attr: &ast::Attribute,
+    whitelist: &FxHashSet<String>,
+    target_features: &mut Vec<String>,
+) {
+    let list = match attr.meta_item_list() {
+        Some(list) => list,
+        None => {
+            let msg = "#[target_feature] attribute must be of the form \
+                       #[target_feature(..)]";
+            tcx.sess.span_err(attr.span, &msg);
+            return
+        }
+    };
+
+    for item in list {
+        if !item.check_name("enable") {
+            let msg = "#[target_feature(..)] only accepts sub-keys of `enable` \
+                       currently";
+            tcx.sess.span_err(item.span, &msg);
+            continue
+        }
+        let value = match item.value_str() {
+            Some(list) => list,
+            None => {
+                let msg = "#[target_feature] attribute must be of the form \
+                           #[target_feature(enable = \"..\")]";
+                tcx.sess.span_err(item.span, &msg);
+                continue
+            }
+        };
+        let value = value.as_str();
+        for feature in value.split(',') {
+            if whitelist.contains(feature) {
+                target_features.push(format!("+{}", feature));
+                continue
+            }
+
+            let msg = format!("the feature named `{}` is not valid for \
+                               this target", feature);
+            let mut err = tcx.sess.struct_span_err(item.span, &msg);
+
+            if feature.starts_with("+") {
+                let valid = whitelist.contains(&feature[1..]);
+                if valid {
+                    err.help("consider removing the leading `+` in the feature name");
+                }
+            }
+            err.emit();
+        }
+    }
+}

src/librustc_trans/callee.rs

@@ -99,8 +99,7 @@ pub fn get_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
         if instance.def.is_inline(tcx) {
             attributes::inline(llfn, attributes::InlineAttr::Hint);
         }
-        let attrs = instance.def.attrs(ccx.tcx());
-        attributes::from_fn_attrs(ccx, &attrs, llfn);
+        attributes::from_fn_attrs(ccx, llfn, instance.def.def_id());
 
         let instance_def_id = instance.def_id();
 

src/librustc_trans/lib.rs

@@ -167,6 +167,7 @@ impl rustc_trans_utils::trans_crate::TransCrate for LlvmTransCrate {
         back::symbol_names::provide(providers);
         back::symbol_export::provide(providers);
         base::provide(providers);
+        attributes::provide(providers);
     }
 
     fn provide_extern(providers: &mut ty::maps::Providers) {