cfi.c

#include <stdarg.h>
#include <stdio.h>

void foo(unsigned n, ...) {
    va_list args;
    va_start(args, n);
    for (unsigned i = 0; i < n; i++) {
        printf("%d\n", va_arg(args, int));
    }
    va_end(args);
}

int main(void) {
    void (*bar)(unsigned, int, int) = (void *)foo;
    bar(2, 5, 10);
    return 0;
}

cfi_output.txt

% clang foo.c -o foo -fsanitize=cfi-icall -fno-sanitize-trap=cfi-icall -fsanitize-recover=cfi-icall -flto
% ./foo 
foo.c:15:5: runtime error: control flow integrity check for type 'void (unsigned int, int, int)' failed during indirect function call
(/home/strcat/foo+0x2a690): note: foo defined here
5
10