foo.s

	.extern bar

	.text
	.globl	foo
	.type	foo, @function
foo:
	.cfi_startproc
	xor %rsp, (%rsp)
	//          exp   RA    len   const -8    plus  dup   deref xor
	.cfi_escape 0x16, 0x10, 0x06, 0x09, 0xf8, 0x22, 0x12, 0x06, 0x27
	pushq	%rbp
	.cfi_def_cfa_offset 16
	.cfi_offset 6, -16
	movq	%rsp, %rbp
	.cfi_def_cfa_register 6
	movl	%edi, -4(%rbp)
	call bar
	movl	-4(%rbp), %eax
	addl	%eax, %eax
	popq	%rbp
	.cfi_def_cfa 7, 8
	xor %rsp, (%rsp)
	ret
	.cfi_endproc

test.c

#include <stdio.h>

int foo(int);

void bar(void)
{
	printf("Hi!\n");
}


int main ()
{
	return foo (4);
}