Disable coverage instrumentation for naked functions

Author: tmiasko

compiler/rustc_hir_analysis/src/collect.rs

@@ -2073,6 +2073,10 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
         }
     }
 
+    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
+        codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
+    }
+
     // Weak lang items have the same semantics as "std internal" symbols in the
     // sense that they're preserved through all our LTO passes and only
     // strippable by the linker.

src/test/codegen/naked-nocoverage.rs

@@ -0,0 +1,19 @@
+// Checks that naked functions are not instrumented by -Cinstrument-coverage.
+// Regression test for issue #105170.
+//
+// needs-asm-support
+// needs-profiler-support
+// compile-flags: -Cinstrument-coverage
+#![crate_type = "lib"]
+#![feature(naked_functions)]
+use std::arch::asm;
+
+#[naked]
+#[no_mangle]
+pub unsafe extern "C" fn f() {
+    // CHECK:       define void @f()
+    // CHECK-NEXT:  start:
+    // CHECK-NEXT:    call void asm
+    // CHECK-NEXT:    unreachable
+    asm!("", options(noreturn));
+}