exercises-llvm-ir.md

Exercises on LLVM-IR

For the following exercises require the usage of the command line tools provided by LLVM, i.e., lli, llc, llvm-as, llvm-link and clang.

The exercises ask you to implement a simple function in LLVM-IR. You can test your solution using a standard C program. Assume that your solution is a function int foo(int) in a module foo.ll. You can test the function by creating something similar to the following

/** Here, include directives, other declarations, etc. */
extern int foo(int);

int main(){
    // ... other code
    if(foo(test1) == expected 1)
        printf("Test 1 passed!"\n);
    // ... other code    
}

Then, you can compile the main to LLVM IR and link it to your solution

$ clang -llvm-emit main.c -c -S
$ llvm-link main.bc foo.bc -o output.bc
$ lli output.bc

Exercise 1

Implement a function that given an integer n computes the factorial n. Provide two version of this function the first one that is recursive and the second one that is iterative.

Exercise 2

Implement a function that given an array of integers a returns the sum of the elements of a.

Exercise 3

Implement a function that given an array of integers a returns the minimum of a.