tests/stack_unwind: Avoid inlining and tail-calls

We want the stack trace to show the correct nesting of functions,
so we need to prevent the compiler from in-lining functions or
performing tail-call optimizations.

Add __noinline to prevent inlining. Add another printf in each
function to avoid tail calls.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

tests/arch/common/stack_unwind/src/main.c

@@ -12,7 +12,7 @@
 static void func1(int a);
 static void func2(int a);
 
-static void func2(int a)
+static void __noinline func2(int a)
 {
 	printf("%d: %s\n", a, __func__);
 
@@ -21,12 +21,14 @@ static void func2(int a)
 	}
 
 	func1(a + 1);
+	printf("bottom %d: %s\n", a, __func__);
 }
 
-static void func1(int a)
+static void __noinline func1(int a)
 {
 	printf("%d: %s\n", a, __func__);
 	func2(a + 1);
+	printf("bottom %d: %s\n", a, __func__);
 }
 
 int main(void)