BPF: fix #[target_feature(enable = "alu32")]

compiler/rustc_feature/src/active.rs

@@ -250,6 +250,7 @@ declare_features! (
     (active, f16c_target_feature, "1.36.0", Some(44839), None),
     (active, riscv_target_feature, "1.45.0", Some(44839), None),
     (active, ermsb_target_feature, "1.49.0", Some(44839), None),
+    (active, bpf_target_feature, "1.53.0", Some(44839), None),
 
     // -------------------------------------------------------------------------
     // feature-group-end: actual feature gates (target features)

compiler/rustc_typeck/src/collect.rs

@@ -2597,6 +2597,7 @@ fn from_target_feature(
                 Some(sym::rtm_target_feature) => rust_features.rtm_target_feature,
                 Some(sym::f16c_target_feature) => rust_features.f16c_target_feature,
                 Some(sym::ermsb_target_feature) => rust_features.ermsb_target_feature,
+                Some(sym::bpf_target_feature) => rust_features.bpf_target_feature,
                 Some(name) => bug!("unknown target feature gate {}", name),
                 None => true,
             };

src/test/codegen/bpf-alu32.rs

@@ -0,0 +1,12 @@
+// compile-flags: --emit=asm --target bpfel-unknown-none
+// only-bpf
+#![crate_type = "lib"]
+#![feature(bpf_target_feature)]
+#![no_std]
+
+#[no_mangle]
+#[target_feature(enable = "alu32")]
+// CHECK: define i8 @foo(i8 returned %arg) unnamed_addr #0 {
+pub unsafe fn foo(arg: u8) -> u8 {
+    arg
+}