In this assignment you will implement a pass to build a program’s CFG from its linear code. This assignment is due on Sunday March 6th at 11:59pm.

For this assignment, you can choose to use either the URCC compiler or LLVM.

Instructions for URCC

1. Checkout and install the URCC compiler (follow the instructions in the README file). Make sure you are using a version of clang between 3.3 and 3.6 or URCC may fail. If you decide to use the CSUG machines, you can use clang 3.6 that is installed in /u/cs255/build-llvm-36/bin.
2. Follow the algorithm in section 5.3.4 of the Cooper & Torczon book (page 241) to write a pass that builds the CFG of the program and visualizes it using graphViz (instructions on how to write a URCC pass are included in the README file).
3. Test your compiler pass on test cases included in the test directory.
4. Explain your implementation in a Readme file. Report all test case failures.
5. Archive your code and the Readme file and submit on Blackboard.

Note: A CFG pass is already implemented in the URCC compiler. You shall not look at that implementation.

Instructions for LLVM

1. Following the same instructions as in assignment 2, create an LLVM project in your CSUG account.
2. Implement a pass that builds the CFG of the program and visualizes it using graphviz. If you need to iterate over instructions in a function, you must use the following code:

   #include "llvm/IR/InstIterator.h"
   
   // F is a pointer to a Function instance
   for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
     errs() << *I << "\n";

3. You can use BGL (Boost Graph Library), which is already installed on CSUG filesystem. Graphviz is included in this library.
4. Test your compiler pass on test cases included in URCC’s repository (https://github.com/dcompiler/urcc/tree/master/tests).
5. Explain your implementation in a Readme file. Report all test case failures.
6. Archive your code and the Readme file and submit on Blackboard.

Note: A CFG pass is already implemented in LLVM. You shall not look at that implementation.