From c2fb99984c2ed4b54f5b8baff26fcc04af71d032 Mon Sep 17 00:00:00 2001
From: Tomasz Miąsko <tomasz.miasko@gmail.com>
Date: Fri, 20 Nov 2020 00:00:00 +0000
Subject: Never inline naked functions

The `#[naked]` attribute disabled prologue / epilogue emission for the
function and it is responsibility of a developer to provide them. The
compiler is no position to inline such functions correctly.

Disable inlining of naked functions at LLVM and MIR level.
---
 src/test/codegen/naked-noinline.rs | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 src/test/codegen/naked-noinline.rs

(limited to 'src/test/codegen')

diff --git a/src/test/codegen/naked-noinline.rs b/src/test/codegen/naked-noinline.rs
new file mode 100644
index 00000000000..2a2208d4fce
--- /dev/null
+++ b/src/test/codegen/naked-noinline.rs
@@ -0,0 +1,30 @@
+// Checks that naked functions are never inlined.
+// compile-flags: -O -Zmir-opt-level=2
+// ignore-wasm32
+#![crate_type = "lib"]
+#![feature(asm)]
+#![feature(naked_functions)]
+
+#[inline(always)]
+#[naked]
+#[no_mangle]
+pub unsafe extern "C" fn f() {
+// Check that f has naked and noinline attributes.
+//
+// CHECK:       define void @f() unnamed_addr [[ATTR:#[0-9]+]]
+// CHECK-NEXT:  start:
+// CHECK-NEXT:    call void asm
+    asm!("", options(noreturn));
+}
+
+#[no_mangle]
+pub unsafe fn g() {
+// Check that call to f is not inlined.
+//
+// CHECK-LABEL: define void @g()
+// CHECK-NEXT:  start:
+// CHECK-NEXT:    call void @f()
+    f();
+}
+
+// CHECK: attributes [[ATTR]] = { naked noinline{{.*}} }
-- 
cgit 1.4.1-3-g733a5