/*
 * Bdragon's single file ifunc torture test for FreeBSD (POWER9 only)
 *
 * Test cases:
 * cc -o ifunc_torture_test ifunc_torture_test.c
 * - use -static / -fpic / -fPIC / -fPIE
 * - use alternate linker with -fuse-ld
 * - use ports gcc
 *
 * Ideal behavior: All lines are identical
 * Acceptable behavior: Lines differ, but only in groups (indicates multiple resolver calls)
 * Unacceptable behavior:
 *  * Missing lines. (Indicates PLT malfunction)
 *  * Program crashes. (Indicates link issues)
 *  * RTLD crashes (with error message). (Indicates assertion hit)
 *  * RTLD crashes (with NO error message). (Indicates assertion hit AND PLT malfunction)
 */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <machine/ifunc.h>
#include <stdint.h>

void indirect1(void);

/* Four implementations making PLT calls (printf), chosen at random */

static void
thefunc_one(void)
{
	printf("This is thefunc one\n");
}

static void
thefunc_two(void)
{
	printf("This is thefunc two\n");
}

static void
thefunc_three(void)
{
	printf("This is thefunc three\n");
}

static void
thefunc_four(void)
{
	printf("This is thefunc four\n");
}

/* POWER9 only plt-less resolver */
static int
arc4random_proxy(int a) {
	unsigned long rndval;
	// Randomness without a PLT call.
	__asm __volatile(".long 0x7c0205e6 | (%0 << 21)" :
			"+r"(rndval));
	return ((int)(rndval % a));
} 

/* Needs D22787 */
DEFINE_UIFUNC(, void, thefunc, (void))
{
        int foo = arc4random_proxy(4); 
	switch (foo) {
		default:
			return &thefunc_four;
		case 0:
			return &thefunc_one;
		case 1:
			return &thefunc_two;
		case 2:
			return &thefunc_three;
	}
}

int
main(int argc, char* argv[]) {
	printf("Inside program!\n");
	printf("Direct call to ifunc (you should see two lines):\n");
	printf("-------------\n");
	thefunc();
	thefunc();
	printf("-------------\n");
	printf("Indirect call to ifunc (you should see two lines):\n");
	printf("-------------\n");
	indirect1();
	indirect1();
	printf("-------------\n");
	printf("Assigning function pointer.\n");
	void (*theptr)(void) = &thefunc;

	printf("About to call via function pointer! (you should see three lines):\n");
	printf("-------------\n");
	(*theptr)();
	(*theptr)();
	(*theptr)();
	printf("-------------\n");
	printf("thefunc is %p\n", thefunc);
	printf("The pointer was %p\n", theptr);
	printf("Made it to the end of the test.\n");
	return 0;
}

void __attribute__((noinline))
indirect1() {
	thefunc();
}