Rollup merge of rust-lang#105193 - tmiasko:naked-nocoverage, r=wesleywiser

Disable coverage instrumentation for naked functions

Fixes rust-lang#105170.

Author: matthiaskrgr

compiler/rustc_codegen_llvm/src/attributes.rs

@@ -258,13 +258,12 @@ pub fn from_fn_attrs<'ll, 'tcx>(
         OptimizeAttr::Speed => {}
     }
 
-    let inline = if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
-        InlineAttr::Never
-    } else if codegen_fn_attrs.inline == InlineAttr::None && instance.def.requires_inline(cx.tcx) {
-        InlineAttr::Hint
-    } else {
-        codegen_fn_attrs.inline
-    };
+    let inline =
+        if codegen_fn_attrs.inline == InlineAttr::None && instance.def.requires_inline(cx.tcx) {
+            InlineAttr::Hint
+        } else {
+            codegen_fn_attrs.inline
+        };
     to_add.extend(inline_attr(cx, inline));
 
     // The `uwtable` attribute according to LLVM is:

compiler/rustc_hir_analysis/src/collect.rs

@@ -2073,6 +2073,11 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: DefId) -> CodegenFnAttrs {
         }
     }
 
+    if codegen_fn_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
+        codegen_fn_attrs.flags |= CodegenFnAttrFlags::NO_COVERAGE;
+        codegen_fn_attrs.inline = InlineAttr::Never;
+    }
+
     // 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.

compiler/rustc_mir_transform/src/inline.rs

@@ -363,10 +363,6 @@ impl<'tcx> Inliner<'tcx> {
             return Err("C variadic");
         }
 
-        if callee_attrs.flags.contains(CodegenFnAttrFlags::NAKED) {
-            return Err("naked");
-        }
-
         if callee_attrs.flags.contains(CodegenFnAttrFlags::COLD) {
             return Err("cold");
         }

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));
+}