only enable/disable aarch64 flags that are not already globally enabled

Author: folkertdev

compiler/rustc_codegen_ssa/src/mir/naked_asm.rs

@@ -188,13 +188,13 @@ fn enable_disable_target_features<'tcx>(
             // https://developer.arm.com/documentation/100067/0611/armclang-Integrated-Assembler/AArch32-Target-selection-directives?lang=en
 
             for feature in features {
-                writeln!(begin, ".arch_extension {}", feature.name).unwrap();
+                // only enable/disable a feature if it is not already globally enabled.
+                // so that we don't infuence subsequent asm blocks
+                if !tcx.sess.unstable_target_features.contains(&feature.name) {
+                    writeln!(begin, ".arch_extension {}", feature.name).unwrap();
 
-                // aarch does not have the push/pop mechanism like riscv below.
-                //
-                // > The .arch_extension directive is effective until the end of the assembly block and is not propagated to subsequent code
-                //
-                // https://github.com/taiki-e/portable-atomic/blob/75a36c33b38c4c68f4095e95f106cfbedce9a914/src/imp/atomic128/aarch64.rs#L330
+                    writeln!(end, ".arch_extension no{}", feature.name).unwrap();
+                }
             }
         }
         Architecture::Riscv32 | Architecture::Riscv64 => {

tests/assembly/naked-fn-aarch64-global-target-feature.rs

@@ -0,0 +1,29 @@
+//@ add-core-stubs
+//@ assembly-output: emit-asm
+//@ compile-flags: --target aarch64-unknown-linux-gnu -Ctarget-feature=+lse
+//@ needs-llvm-components: aarch64
+
+#![crate_type = "lib"]
+#![feature(no_core, naked_functions)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
+
+// check that a naked function using target features does not disable these features for subsequent
+// asm blocks.
+
+// CHECK-LABEL: a:
+#[no_mangle]
+#[naked]
+#[target_feature(enable = "lse")]
+unsafe extern "C" fn a() {
+    naked_asm!("casp x2, x3, x2, x3, [x1]")
+}
+
+// CHECK-LABEL: b:
+#[no_mangle]
+#[naked]
+unsafe extern "C" fn b() {
+    naked_asm!("casp x2, x3, x2, x3, [x1]")
+}