My workflow with GDB and git -- part 1

Table of Contents

This post is actually a “reply” to Gary Benson’s Working on gdb post.

I have been working with GDB for quite some time now, and even though the project officially uses CVS (yes, you read it correctly, it is CVS indeed!) as its version control system, fortunately we also have a git mirror. In the end, what happens is that almost every developer uses the git mirror and just goes to CVS to commit something. But this is another discussion. Aside of this git mirror, we also have the Archer repository (which uses git by default).

My plan here is to show you how I do my daily work with GDB. The workflow is pretty simple, but maybe you will see something here that might help you.

Checking out the code

The first thing to do is to check out the code. I only have one GDB repository here, and I make branches out of it whenever I want to hack. So, to check out (or clone, in git’s parlance) the code, I do (or did):

With this, we have just cloned the GDB repository, and also added another remote (i.e., repository). This is useful because we might want to hack on a branch which is on Archer, but use GDB’s master branch as a base.

Create a new branch for your work

So, now it’s time to create a new branch for you. Here I use one of my little “tricks” (taught to me by my friend Dodji), which is the command git-new-workdir. This is a nice command because it creates a new working directory for your project!

Maybe you’re wondering why this is so cool. Well, if you ever worked with git, and more specifically, if you ever used more than one branch at a time, then maybe you will understand my excitement. In this scenario, having to constantly switch between the branches is not something rare. When you have uncommited work in your tree you can always use git stash, but that is not the ideal solution (for me). Sometimes I would forget what was on the stash, and later when I checked it, it was full of crap. Also, I like to have a separate directory for every project I am working on.

It is also important to mention that git-new-workdir is under the directory /usr/share/doc/git-VERSION/contrib/workdir/, so I created an alias that will automagically call the script for me:

So, after setting up the script, here is what I do:

Build GDB

In order to build the project, I create a build-64 directory inside my project directory (which, in the example above, is work/lazy-debuginfo-reading).

GDB fortunately supports VPATH building (i.e., build the project outside of the source tree). I strongly recommend you to use it.

As you may have noticed, I use -g3 (include debuginfo) and -O0 (do not optimize the code) in CFLAGS. Also, since some of the features I work on may affect code in other architectures, I use --enable-targets=all. It will tell configure to compile everything related to all architectures (not only x86_64, for example). At last, I specify a separate debug directory which GDB should use to search for debuginfo files.

Finalizing (for now)

After that, you will have a fresh GDB binary compiled in the build-64 directory. But that is not enough yet, since you will also want to test GDB and make sure you didn’t insert a bug while hacking on it. In my next post, I will explain what is my “testflow”. I hope it will be useful for someone :-).

Stay tuned!

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