HW22
COP-3402

1. Are function-local variables (auto in C) allocated at compile-time or run-time?
2. If some function definition has a local variable x, will that variable always be assigned a single memory location in any possible program that has such a function?
3. The following are the contents of a stack frame, label which ones are caller created and which are callee created in the x86 64 System V ABI:
   • Callee-saved registers
   • Stack parameters
   • Return address
   • Local variables
   • Register parameters
   • Old base pointer
4. What register in the x86 64 System V ABI is meant to hold a pointer to the currently-executing function's stack frame?

5. What is the greatest number of active stack frames that will exist in memory at one time for the factorial function in the following program?

   #include <stdio.h>
   
   int factorial(int n) {
     if (n < 2) {
       return 1;
     } else {
       return n * factorial(n - 1);
     }
   }
   
   int main() {
     int n = 5;
     printf("factorial(%d) = %d\n", n, factorial(n));
   }