Designing a WebAssembly toolchain for Ada/SPARK

WebAssembly (Wasm) is a binary instruction format for a stack-based virtual machine, which was designed as a portable compilation target for programming languages. Wasm can be executed in browsers, native runtimes and embedded contexts.The goal of my six-month internship at AdaCore was to draft a design for a toolchain that would support an Ada/SPARK workflow to WebAssembly. In this blog post the drafted design is introduced and discussed.

Announcing Updates to learn.adacore.com

Going beyond Ada 2022

As we've seen previously in Ada 2022 support in GNAT, the support for Ada 2022 is now mostly there for everyone to take advantage of. We're now crossing fingers for this new revision to be officially stamped by ISO in 2022.

The FACE™ open systems strategy gaining traction in the avionics industry

The FACE™ approach is a government-industry initiative for reducing defense system life cycle costs through portable and reusable software components. It consists of a technical approach — a software standard based on well-defined common interfaces — and a business strategy for encouraging the development and deployment of FACE conformant products.

Make with Ada 2020: Disaster Management with Smart Circuit Breaker

Shahariar's project ensures safety against electrical fire or shock during an earthquake, flood, gas leakage or fire breakout by disconnecting the mains with a smart circuit breaker. Additionally, this project won a finalist prize in the 2019/20 Make with Ada competition.

Make with Ada 2020: The SmartBase - IoT Adjustable Bed

John Singleton's The SmartBase makes your existing adjustable bed safer and easier to use by adding voice control and safe (and fun!) LED underbed lighting! Additionally, this project won first place prize in the 2019/20 Make with Ada competition.

Proving properties of constant-time crypto code in SPARKNaCl

Over the last few months, I developed a SPARK version of the TweetNaCl cryptographic library. This was made public on GitHub in February 2020, under the 2-clause BSD licence. This blog entry goes into a bit more technical detail on one particular aspect of the project: the challenge of re-writing and verifying "constant time" algorithms using SPARK.

Android application with Ada and WebAssembly

Having previously shown how to create a Web application in Ada, it's not so difficult to create an Android application in Ada. Perhaps the simplest way is to install Android Studio. Then just create a new project and choose "Empty Activity". Open the layout, delete TextView and put WebView instead.

Witnessing the Emergence of a New Ada Era

For nearly four decades the Ada language (in all versions of the standard) has been helping developers meet the most stringent reliability, safety and security requirements in the embedded market. As such, Ada has become an entrenched player in its historic A&D niche, where its technical advantages are recognized and well understood. Ada has also seen usage in other domains (such as medical and transportation) but its penetration has progressed at a somewhat slower pace. In these other markets Ada stands in particular contrast with the C language, which, although suffering from extremely well known and documented flaws, remains a strong and seldom questioned default choice. Or at least, when it’s not the choice, C is still the starting point (a gateway drug?) for alternatives such as C++ or Java, which in the end still lack the software engineering benefits that Ada embodies..

Combining GNAT with LLVM

Presenting the GNAT LLVM projectAt AdaCore labs, we have been working for some time now on combining the GNAT Ada front-end with a different code generator than GCC.

Using Ada for a Spanish Satellite Project

I am an Associate Professor at Polytechnic University of Madrid’s (Universidad Politécnica de Madrid / UPM) in the Department of Architecture and Technology of Computer Systems. For the past several years I have been directing a team of colleagues and students in the development of a UPMSat-2 microsatellite. The project originally started in 2013 as a follow-to the UPM-SAT 1, launched by an Ariane-4 in 1995.

Public Ada Training Paris June 3-7, 2019

This course is geared to software professionals looking for a practical introduction to the Ada language with a focus on embedded systems, including real-time features as well as critical features introduced in Ada 2012. By attending this course you will understand and know how to use Ada for both sequential and concurrent applications, through a combination of live lectures from AdaCore's expert instructors and hands-on workshops using AdaCore's latest GNAT technology. AdaCore will provide an Ada 2012 tool-chain and ARM-based target boards for embedded workshops. No previous experience with Ada is required.

Ten Years of Using SPARK to Build CubeSat Nano Satellites With Students

My colleague, Carl Brandon, and I have been running the CubeSat Laboratory at Vermont Technical College (VTC) for over ten years. During that time we have worked with nearly two dozen students on building and programming CubeSat nano satellites. Because of their general inexperience, and because of the high student turnover rate that is natural in an educational setting, our development process is often far from ideal. Here SPARK has been extremely valuable to us. What we lack in rigor of the development process we make up for in the rigor of the SPARK language and tools. In November 2013 we launched a low Earth orbiting CubeSat. The launch vehicle contained 13 other university built CubeSats. Most were never heard from. One worked for a few months. Ours worked for two years until it reentered Earth's atmosphere as planned in November 2015.

AdaFractal Part1: Ada with a Portable GUI

The is the first part of a multiple part post that covers the development of the AdaFractal project. The idea was to create fractals in Ada. Here we will cover how to use AWS to create a flexible and portable way to display the generated fractals without using bulky graphics libraries.

Public Ada Training Paris, France Dec 3 - 7, 2018

This course is geared to software professionals looking for a practical introduction to the Ada language with a focus on embedded systems, including real-time features as well as critical features introduced in Ada 2012. By attending this course you will understand and know how to use Ada for both sequential and concurrent applications, through a combination of live lectures from AdaCore's expert instructors and hands-on workshops using AdaCore's latest GNAT technology. AdaCore will provide an Ada 2012 tool-chain and ARM-based target boards for embedded workshops. No previous experience with Ada is required.

Learn.adacore.com is here

We are very proud to announce the availability of our new Ada and SPARK learning platform learn.adacore.com, which will replace AdaCoreU(niversity) e-learning platform. Learn all about it in this blog post.

Taking on a Challenge in SPARK

Last week, the programmer Hillel posted a challenge (the link points to a partial postmortem of the provided solutions) on Twitter for someone to prove a correct implementation of three small programming problems: Leftpad, Unique, and Fulcrum.

Two Days Dedicated to Sound Static Analysis for Security

​AdaCore has been working with CEA, Inria and NIST to organize a two-days event dedicated to sound static analysis techniques and tools, and how they are used to increase the security of software-based systems. The program gathers top-notch experts in the field, from industry, government agencies and research institutes, around the three themes of analysis of legacy code, use in new developments and accountable software quality. Here is why it is worth attending.

The Road to a Thick OpenGL Binding for Ada: Part 1

This blog post is part one of a tutorial based on the OpenGLAda project and will cover some the background of the OpenGL API and the basic steps involved in importing platform-dependent C functions.

Leveraging Ada Run-Time Checks with Fuzz Testing in AFL

Fuzzing is a very popular bug finding method. The concept, very simple, is to continuously inject random (garbage) data as input of a software component, and wait for it to crash. If, like me, you find writing robustness test tedious and not very efficient in finding bugs, you might want to try fuzzing your Ada code.Here's a recipe to fuzz-test your Ada code, using American Fuzzy Lop and all the runtime checks your favorite Ada compiler can provide.Let's see (quickly) how AFL works, then jump right into fuzzing 3 open-source Ada libraries: ZipAda, AdaYaml, and GNATCOLL.JSON.

Unity & Ada

Using Ada technologies to develop video games doesn’t sound like an an obvious choice - although it seems like there could be an argument to be made. The reverse, however, opens some more straightforward perspectives.

The latest Mixed Programming with Ada lectures at the AdaCore University

I recently joined AdaCore as a Technical Account Manager with an initial focus on the UK and Scandinavian regions, but for the last 12 months I've been busy working on the AdaCore University. The most recent addition to which is a course on Mixed Language Programming with Ada, and it includes lectures on the integration of Ada with C, C++ and Java. The course covers some advanced topics like mixed language object orientation, techniques for using Ada strong typing to combat known issue with C pointers and the pitfalls that are encountered when mixing native Ada code with Java at runtime. This course clearly demonstrates that Ada has strong support for integration with C, C++ and Java and it proves there are no technical barriers to its adoption in modern mixed language software systems.

Studies of Contracts in Practice

Two recent research papers focus on how program contracts are used in practice in open source projects, in three languages that support contracts (Eiffel obviously, Java with JML contracts and C# with Code Contracts). I'm reporting what I found interesting (and less so) in these two studies.

SPARK 2014 Rationale: Mixing SPARK and Ada Code

The first step before any formal verification work with SPARK is to delimitate the part of the code that will be subject to formal verification within the overall Ada application. This post presents the solution we've come up with for SPARK 2014.

SPARK 2014 Rationale: Pre-call and Pre-loop Values

Subprogram contracts are commonly presented as special assertions: the precondition is an assertion checked at subprogram entry, while the postcondition is an assertion checked at subprogram exit. A subtlety not covered by this simplified presentation is that postconditions are really two-state assertions: they assert properties over values at subprogram exit and values at subprogram entry. A special attribute Old is defined in Ada 2012 to support these special assertions. A special attribute Loop_Entry is defined in SPARK 2014 to support similar special assertions for loops.

SPARK 2014 Rationale: Specification Functions

Specifying a program's behavior is seldom expressible in a satisfiable way without the capability of abstraction provided by function calls. Yet, specification functions must obey specific constraints like absence of side-effects and termination, that have led to different solutions in various specification languages. Here is what we did in SPARK 2014.

SPARK 2014 Rationale: Contract Cases

Besides the usual expression of a subprogram contract as a pair of a precondition and a postcondition, SPARK 2014 provides a way to express such a contract by cases. A little history helps understanding how we came up with this new feature.