Project for CSC 255/455, Spring 2010

Introduction

In the project, you will add your own optimization passes in the Gnu C Compiler, GCC 4.2.2. It is not the most recent GCC, but should be sufficient for our project. You have to know the basic framework of GCC and how to manipulate the intermediate form, the gimple tree, for program analysis and transformation. This page includes many suggestions that will help you in the process. Please read the entire page and the pages about source browsing and debugging before you start.

Compilation, Installation and Run

* Check out the code from GCC read-only repository, following the commands below.

mkdir gcc

cd gcc

svn co svn://gcc.gnu.org/svn/gcc/branches/gcc-4_4-branch gcc

mkdir obj

cd obj

../gcc/configure --prefix=$INSTALL_DIR

// $INSTALL_DIR is the directory you want to install your compiler

make

make install

* Use either our desktop or personal machine or one of the public use machines in the CS department. When using department machines, due to the shortage of space for the /home directory, it is better to put your code under /localdisk .

* Invoke your pass: use -O2 -fcs255

* Put your own code into gcc-4.2.2/gcc/cs255.c

* Use make for your testing: see An Example for Makefile

* About turn in: You need to turn in the file containing source code (normally only cs255.c), along with the README document describing the design, implementation and testing results when applicable. README is a very important part of your project, so lease take it seriously. To submit your work, make a new folder, put cs255.c and README into it, and then call /u/cs455/TURN_IN . in the folder (Don't forget the "."). If you have problem with the submit script, feel free to send the two files to me by email.

* To prevent the problem of hardware incompatibility, you'd better build your compiler and use it and run the compiled executables on the same kind of machines.

* If you are not familiar with subversion, take a look at the VersionStuff page.

* Gnu's wiki page on the generic installation procedure for GCC.

Browsing GCC code

* Gnu's wiki page on GCC getting started.

* You can open in a web browser the following file /p/compiler/built/gcc-4.2.2/doxygen/ and start with index.html for a local copy of Gcc 4.2.2 documentation by doxygen. If you copy, the directory needs about 600MB disk space.

* Installing and using Doxygen to generate your own documentation

* Good Assorted Topics Page from developer site also has a decent overview.

* Using Emacs (especially useful when you work remotely)

* Using Eclipse (w/ CDT). You can download Eclipse IDE for C/C++ Developers (68 MB) from here.

Debugging

* Gnu's wiki page on debugging GCC (with instructions on using gdb inside emacs)

* How to debug your compiler

GCC Data Structures and Internal Representations

* Some useful GCC Data Structures

* Chapter 8, 9, 12 and 13 of Gcc Internals

* Gimple on Wikipedia

Part 1: Trivial (5%)(Individual Project) (Due: Feb. 21 11:59pm)

In this part, you will add a pass that will insert code into a program to count and output the number of executed statements when the program executes. You need to first add a call at the beginning of the main function, which has a global counter initialized to 0; then add a call before each gimple statement, which increments the counter; and finally add a call at the exit, which reports the run-time instruction counts. The three functions are provided in cs255-lib.c and cs255-lib.h:

* Initialization: you'll need to add it at the entry of the main function

* Increment: to be added before each real gimple statements (all except for labels)

* Report: to be added at all possible exits of the program

* Remember to add #include "cs255-lib.h" in your own testing programs.

This part should take at most tens of lines of code and no more than a day (including half an hour compiling the compiler for the first time). The purpose is to get you familiar with GCC and the basic GCC functions that you'll need for adding your optimization passes. Reading the relevant, existing code (in gcc-4.2.2/gcc/cs255.c) is the best way to help you writing your new code in an existing system. For instance, the code for counting the number of basic blocks and statements statically is already in the file. The code for getting the dynamic count of the basic blocks is also given.<br>

For testing, there are some open test cases. You may use the results from them to check your code with your classmates. And they are very useful in following parts and final competition.

* Set ALLOWTOPICCHANGE = ChenDing, XiaoyaXiang

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Topic revision: r2 - 2010-02-15 - XiaoyaXiang
 
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