Do not request sanitizers for naked functions

Naked functions can only contain inline asm, so any instrumentation
inserted by sanitizers is illegal. Don't request it.

Fixes #129224.

Author: nikic

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -411,26 +411,31 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
             // the string "false". Now it is disabled by absence of the attribute.
             to_add.push(llvm::CreateAttrStringValue(cx.llcx, "branch-target-enforcement", "false"));
         }
-    } else if llvm_util::get_version() >= (19, 0, 0) {
-        // For non-naked functions, set branch protection attributes on aarch64.
-        if let Some(BranchProtection { bti, pac_ret }) =
-            cx.sess().opts.unstable_opts.branch_protection
-        {
-            assert!(cx.sess().target.arch == "aarch64");
-            if bti {
-                to_add.push(llvm::CreateAttrString(cx.llcx, "branch-target-enforcement"));
-            }
-            if let Some(PacRet { leaf, key }) = pac_ret {
-                to_add.push(llvm::CreateAttrStringValue(
-                    cx.llcx,
-                    "sign-return-address",
-                    if leaf { "all" } else { "non-leaf" },
-                ));
-                to_add.push(llvm::CreateAttrStringValue(
-                    cx.llcx,
-                    "sign-return-address-key",
-                    if key == PAuthKey::A { "a_key" } else { "b_key" },
-                ));
+    } else {
+        // Do not set sanitizer attributes for naked functions.
+        to_add.extend(sanitize_attrs(cx, codegen_fn_attrs.no_sanitize));
+
+        if llvm_util::get_version() >= (19, 0, 0) {
+            // For non-naked functions, set branch protection attributes on aarch64.
+            if let Some(BranchProtection { bti, pac_ret }) =
+                cx.sess().opts.unstable_opts.branch_protection
+            {
+                assert!(cx.sess().target.arch == "aarch64");
+                if bti {
+                    to_add.push(llvm::CreateAttrString(cx.llcx, "branch-target-enforcement"));
+                }
+                if let Some(PacRet { leaf, key }) = pac_ret {
+                    to_add.push(llvm::CreateAttrStringValue(
+                        cx.llcx,
+                        "sign-return-address",
+                        if leaf { "all" } else { "non-leaf" },
+                    ));
+                    to_add.push(llvm::CreateAttrStringValue(
+                        cx.llcx,
+                        "sign-return-address-key",
+                        if key == PAuthKey::A { "a_key" } else { "b_key" },
+                    ));
+                }
             }
         }
     }
@@ -485,7 +490,6 @@ pub(crate) fn llfn_attrs_from_instance<'ll, 'tcx>(
     if let Some(backchain) = backchain_attr(cx) {
         to_add.push(backchain);
     }
-    to_add.extend(sanitize_attrs(cx, codegen_fn_attrs.no_sanitize));
     to_add.extend(patchable_function_entry_attrs(cx, codegen_fn_attrs.patchable_function_entry));
 
     // Always annotate functions with the target-cpu they are compiled for.

tests/codegen/naked-asan.rs

@@ -0,0 +1,22 @@
+// Make sure we do not request sanitizers for naked functions.
+
+//@ only-x86_64
+//@ needs-sanitizer-address
+//@ compile-flags: -Zsanitizer=address
+
+#![crate_type = "lib"]
+#![no_std]
+#![feature(abi_x86_interrupt, naked_functions)]
+
+// CHECK: define x86_intrcc void @page_fault_handler(ptr {{.*}}%0, i64 {{.*}}%1){{.*}}#[[ATTRS:[0-9]+]] {
+// CHECK-NOT: memcpy
+#[naked]
+#[no_mangle]
+pub extern "x86-interrupt" fn page_fault_handler(_: u64, _: u64) {
+    unsafe {
+        core::arch::asm!("ud2", options(noreturn));
+    }
+}
+
+// CHECK: #[[ATTRS]] =
+// CHECK-NOT: sanitize_address