Gracefully handle #[target_feature] on statics

The was careful around not calling `fn_sig` on not-functions but well,
it wasn't careful enough. This commit makes it a little more careful and
also adds tests for a bunch more item kinds.

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -61,25 +61,29 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
 
     let supported_target_features = tcx.supported_target_features(LOCAL_CRATE);
 
-    // In some cases, attribute are only valid on functions, but it's the `check_attr`
-    // pass that check that they aren't used anywhere else, rather this module.
-    // In these cases, we bail from performing further checks that are only meaningful for
-    // functions (such as calling `fn_sig`, which ICEs if given a non-function). We also
-    // report a delayed bug, just in case `check_attr` isn't doing its job.
-    let validate_fn_only_attr = |attr_sp| -> bool {
-        let def_kind = tcx.def_kind(did);
-        if let DefKind::Fn | DefKind::AssocFn | DefKind::Variant | DefKind::Ctor(..) = def_kind {
-            true
-        } else {
-            tcx.sess.delay_span_bug(attr_sp, "this attribute can only be applied to functions");
-            false
-        }
-    };
-
     let mut inline_span = None;
     let mut link_ordinal_span = None;
     let mut no_sanitize_span = None;
+
     for attr in attrs.iter() {
+        // In some cases, attribute are only valid on functions, but it's the `check_attr`
+        // pass that check that they aren't used anywhere else, rather this module.
+        // In these cases, we bail from performing further checks that are only meaningful for
+        // functions (such as calling `fn_sig`, which ICEs if given a non-function). We also
+        // report a delayed bug, just in case `check_attr` isn't doing its job.
+        let fn_sig = || {
+            use DefKind::*;
+
+            let def_kind = tcx.def_kind(did);
+            if let Fn | AssocFn | Variant | Ctor(..) = def_kind {
+                Some(tcx.fn_sig(did))
+            } else {
+                tcx.sess
+                    .delay_span_bug(attr.span, "this attribute can only be applied to functions");
+                None
+            }
+        };
+
         if attr.has_name(sym::cold) {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::COLD;
         } else if attr.has_name(sym::rustc_allocator) {
@@ -169,8 +173,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
                 }
             }
         } else if attr.has_name(sym::cmse_nonsecure_entry) {
-            if validate_fn_only_attr(attr.span)
-                && !matches!(tcx.fn_sig(did).skip_binder().abi(), abi::Abi::C { .. })
+            if let Some(fn_sig) = fn_sig()
+                && !matches!(fn_sig.skip_binder().abi(), abi::Abi::C { .. })
             {
                 struct_span_err!(
                     tcx.sess,
@@ -189,8 +193,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
             codegen_fn_attrs.flags |= CodegenFnAttrFlags::THREAD_LOCAL;
         } else if attr.has_name(sym::track_caller) {
             if !tcx.is_closure(did.to_def_id())
-                && validate_fn_only_attr(attr.span)
-                && tcx.fn_sig(did).skip_binder().abi() != abi::Abi::Rust
+                && let Some(fn_sig) = fn_sig()
+                && fn_sig.skip_binder().abi() != abi::Abi::Rust
             {
                 struct_span_err!(tcx.sess, attr.span, E0737, "`#[track_caller]` requires Rust ABI")
                     .emit();
@@ -222,7 +226,8 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
             }
         } else if attr.has_name(sym::target_feature) {
             if !tcx.is_closure(did.to_def_id())
-                && tcx.fn_sig(did).skip_binder().unsafety() == hir::Unsafety::Normal
+                && let Some(fn_sig) = fn_sig()
+                && fn_sig.skip_binder().unsafety() == hir::Unsafety::Normal
             {
                 if tcx.sess.target.is_like_wasm || tcx.sess.opts.actually_rustdoc {
                     // The `#[target_feature]` attribute is allowed on

tests/ui/target-feature/invalid-attribute.rs

@@ -14,6 +14,21 @@
 
 #![warn(unused_attributes)]
 
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+extern crate alloc;
+//~^ NOTE not a function
+
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+use alloc::alloc::alloc;
+//~^ NOTE not a function
+
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+extern "Rust" {}
+//~^ NOTE not a function
+
 #[target_feature = "+sse2"]
 //~^ ERROR malformed `target_feature` attribute
 #[target_feature(enable = "foo")]
@@ -59,6 +74,11 @@ union Qux {
     f2: u16,
 }
 
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+type Uwu = ();
+//~^ NOTE not a function
+
 #[target_feature(enable = "sse2")]
 //~^ ERROR attribute should be applied to a function
 trait Baz {}
@@ -69,6 +89,21 @@ trait Baz {}
 #[target_feature(enable = "sse2")]
 unsafe fn test() {}
 
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+static A: () = ();
+//~^ NOTE not a function
+
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+impl Quux for u8 {}
+//~^ NOTE not a function
+
+#[target_feature(enable = "sse2")]
+//~^ ERROR attribute should be applied to a function
+impl Foo {}
+//~^ NOTE not a function
+
 trait Quux {
     fn foo();
 }

tests/ui/target-feature/invalid-attribute.stderr

@@ -1,11 +1,38 @@
 error: malformed `target_feature` attribute input
-  --> $DIR/invalid-attribute.rs:17:1
+  --> $DIR/invalid-attribute.rs:32:1
    |
 LL | #[target_feature = "+sse2"]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: must be of the form: `#[target_feature(enable = "name")]`
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:34:1
+  --> $DIR/invalid-attribute.rs:17:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | extern crate alloc;
+   | ------------------- not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:22:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | use alloc::alloc::alloc;
+   | ------------------------ not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:27:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | extern "Rust" {}
+   | ---------------- not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:49:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -14,7 +41,7 @@ LL | mod another {}
    | -------------- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:39:1
+  --> $DIR/invalid-attribute.rs:54:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -23,7 +50,7 @@ LL | const FOO: usize = 7;
    | --------------------- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:44:1
+  --> $DIR/invalid-attribute.rs:59:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -32,7 +59,7 @@ LL | struct Foo;
    | ----------- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:49:1
+  --> $DIR/invalid-attribute.rs:64:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -41,7 +68,7 @@ LL | enum Bar {}
    | ----------- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:54:1
+  --> $DIR/invalid-attribute.rs:69:1
    |
 LL |   #[target_feature(enable = "sse2")]
    |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -54,7 +81,16 @@ LL | | }
    | |_- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:62:1
+  --> $DIR/invalid-attribute.rs:77:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | type Uwu = ();
+   | -------------- not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:82:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -63,7 +99,34 @@ LL | trait Baz {}
    | ------------ not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:85:5
+  --> $DIR/invalid-attribute.rs:92:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | static A: () = ();
+   | ------------------ not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:97:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | impl Quux for u8 {}
+   | ------------------- not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:102:1
+   |
+LL | #[target_feature(enable = "sse2")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |
+LL | impl Foo {}
+   | ----------- not a function definition
+
+error: attribute should be applied to a function definition
+  --> $DIR/invalid-attribute.rs:120:5
    |
 LL |       #[target_feature(enable = "sse2")]
    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -75,7 +138,7 @@ LL | |     }
    | |_____- not a function definition
 
 error: attribute should be applied to a function definition
-  --> $DIR/invalid-attribute.rs:93:5
+  --> $DIR/invalid-attribute.rs:128:5
    |
 LL |     #[target_feature(enable = "sse2")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -84,25 +147,25 @@ LL |     || {};
    |     ----- not a function definition
 
 error: the feature named `foo` is not valid for this target
-  --> $DIR/invalid-attribute.rs:19:18
+  --> $DIR/invalid-attribute.rs:34:18
    |
 LL | #[target_feature(enable = "foo")]
    |                  ^^^^^^^^^^^^^^ `foo` is not valid for this target
 
 error: malformed `target_feature` attribute input
-  --> $DIR/invalid-attribute.rs:22:18
+  --> $DIR/invalid-attribute.rs:37:18
    |
 LL | #[target_feature(bar)]
    |                  ^^^ help: must be of the form: `enable = ".."`
 
 error: malformed `target_feature` attribute input
-  --> $DIR/invalid-attribute.rs:24:18
+  --> $DIR/invalid-attribute.rs:39:18
    |
 LL | #[target_feature(disable = "baz")]
    |                  ^^^^^^^^^^^^^^^ help: must be of the form: `enable = ".."`
 
 error[E0658]: `#[target_feature(..)]` can only be applied to `unsafe` functions
-  --> $DIR/invalid-attribute.rs:28:1
+  --> $DIR/invalid-attribute.rs:43:1
    |
 LL | #[target_feature(enable = "sse2")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -114,13 +177,13 @@ LL | fn bar() {}
    = help: add `#![feature(target_feature_11)]` to the crate attributes to enable
 
 error: cannot use `#[inline(always)]` with `#[target_feature]`
-  --> $DIR/invalid-attribute.rs:67:1
+  --> $DIR/invalid-attribute.rs:87:1
    |
 LL | #[inline(always)]
    | ^^^^^^^^^^^^^^^^^
 
 error[E0658]: `#[target_feature(..)]` can only be applied to `unsafe` functions
-  --> $DIR/invalid-attribute.rs:77:5
+  --> $DIR/invalid-attribute.rs:112:5
    |
 LL |     #[target_feature(enable = "sse2")]
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -131,6 +194,6 @@ LL |     fn foo() {}
    = note: see issue #69098 <https://github.com/rust-lang/rust/issues/69098> for more information
    = help: add `#![feature(target_feature_11)]` to the crate attributes to enable
 
-error: aborting due to 15 previous errors
+error: aborting due to 22 previous errors
 
 For more information about this error, try `rustc --explain E0658`.