patch – patch

In just a few short weeks it is time for the annual NDC Techtown conference where I this year will be giving the talk Mastering MC/DC from first principles.

A few days ago I pushed support for coverage suppression in GCC.

This post describes a proposal and is a call for clients, if you will.

Graph improvements I wanted zcov to quickly and naturally show the coverage status of a piece of code.

GCC 16 will probably release in a couple of months, and comes with a couple of my patches.

2025 in a minute 2025 was an eventful year.

There are many good reasons to maintain a proper git history, with deliberately crafted and focused commits, a state that builds, and good messages that provide context, motivation, and reasoning for the change.

One of the aspects of Guix that really sets it apart from other package managers is how there is not much difference in power between the user and the repository.

Drawing insights We can draw interesting insights from measuring code coverage.

The last post used custom replacement functions and allocator interfaces to simulate allocation failures for testing purposes.

This is a trivial C++ function that does an unchecked access of an array element.

In this post we will work with the basic structure of a switch in a loop, and look at how slightly different decisions and designs affect the complexity and the testing requirements.

In this post we will use path coverage as a guide for testing a C function and explore how a light rewrite improves our ability to test it.

I have been wanting to type up some notes on effective code coverage for a while.

I saw something puzzling today while using zcov – a function I didn’t write that had no coverage.

This post is based on an interesting case NASA brought me; a small test program with a phantom condition.

GCC 15.1 was released today, and it comes with prime path coverage support!

I am happy to announce that the prime path coverage support has been merged into GCC mainline.

I gave a talk today at the Johnson Space Center in Houston, on the GCC coverage features I have done with them.

My paper on Modified Condition/Decision Coverage in GCC is published (in preprint)!

Line coverage is typically the first structured metric looked at, and it provides a rough and imprecise measure of how thoroughly the test harness exercises the code.

I am excited to announce my latest project, under the name zcov.

NASA reported an odd crash in gcov, and I found it interesting and deep enough to warrant describing the root cause and the path it took me on.

This year’s Techtown conference in Kongsberg is through, and I wanted to do a trip report of sorts.

The prime path coverage support is shaping up nicely, so I wanted to write a bit about the last series of improvements to the upcoming prime path coverage feature in gcc. gcov reports Path coverage differs from statement, branch, and condition coverage in…

It’s time for another progress report.

After the success of getting MC/DC support into gcc, NASA decided to keep funding the project and focus on (prime) path coverage.

I have to admit, it feels quite nice to finally write this post.

I ran into an interesting problem when adding support for Modified Condition/Decision Coverage (MC/DC) in gcc (a topic for a later post): how do you large scale test a new compiler feature?