DIY vs Buy: A Short Guide on Toolchain Validation for Functional Safety

• Dual brake controllers in a car
• Backup ventilators in a hospital
• or triple-redundant flight computers in aerospace

That stuff is obvious because you can see it. But what often gets overlooked is the invisible layer: the software toolchain.

If your compiler silently miscompiles a single line of code, or if a build flag changes an optimization in ways you didn’t expect, it doesn’t matter how many redundant systems you bolted on.

Your system can be unsafe because of your compiler. And you might not even know it until it’s too late.

This is why standards like ISO 26262, IEC 62304, and IEC 61508 explicitly mention the need for confidence in your tools. And for us as embedded engineers, that boils down to toolchain validation.

But here’s the catch: validating a toolchain sounds simple until you actually try it.

What looks like “just check the compiler” quickly turns into months of effort, documentation, and re-validation every time your tools change.

Over the years, I’ve seen teams underestimate this more times than I can count.

The goal of this guide is to save you from that trap.

We’ll look at the mistakes teams make, the reality of DIY validation, and why, for many organizations, buying a pre-certified toolchain is the smarter path.

The Reality of Functional Safety Certification

On the surface, toolchain validation seems straightforward. Run some tests, hand the results to auditors, and move on. Right?

Not quite.

Safety standards treat software tools as potential sources of systematic faults.

Hardware faults are random; you can catch them with redundancy.

But a systematic fault? Like a compiler optimizing away a critical safety check?

That one can sit undetected for years, silently undermining your proof of safety.

Validation is less about “does it work right now” and more about whether we can prove it will work reliably, every time, under our conditions. That means:

• Showing the tool has a proven track record under use cases like yours.
• Running test cases that are broad and relevant enough to give confidence.
• Producing documentation that auditors can trace back to requirements.
• Repeating the whole exercise whenever the toolchain changes (even for something as “small” as a patch update)

That sounds heavy, because it is.

Teams that expect this to be a quick checkbox are usually shocked at the amount of structure, resources, and discipline it demands.

Common Mistakes Teams Make

Even experienced embedded teams can stumble when functional safety enters the mix.

I’ve seen the same mistakes repeat across industries, whether it’s automotive, medical, or industrial automation.

Mistake #1: Underestimating Cost & Scope

The classic pitfall is treating toolchain validation as a side task. In reality, it deserves to be treated as a dedicated project of its own.

You’ll need people who understand compilers, safety standards, and test design, not just application engineers.

You’ll need weeks (more often months) to run tests, analyze failures, and document everything. I’ve seen teams budget “a few weeks” and still be scrambling months later.

Mistake #2: Assuming Certification is One-and-Done

Managers often assume you validate once and reuse forever. Unfortunately, that’s not how safety standards work.

Change compiler versions? Flip an optimization flag? Change static analyzer versions? Each of those changes can trigger partial or full re-validation.

The moment your toolchain changes, your original proof is no longer valid.

I’ve seen projects delayed by something as innocent as upgrading GCC midway.

You might say “We will freeze the toolchain and we’re good”. Well, in that case, you’re asking for bugs and security risks, because compilers get updated for a reason.

Mistake #3: Treating Validation as “Just Running Tests”

Buying or writing a giant test suite might sound like the solution. However, safety standards require much more: traceability, risk analysis, and evidence.

It’s not just “did the compiler pass tests”, it’s more than that:

• Which requirements did those tests cover?
• What residual risks remain?
• How do we mitigate them?

That’s the kind of paperwork auditors are looking for. And skipping it is a recipe for red flags later.

Mistake #4: Leadership Blind Spots

From the outside, validation looks like a line item on a budget. But the real cost isn’t dollars, it’s engineering time.

Every week your best engineers spend running validation is a week they’re not building product features or improving reliability.

The hidden opportunity cost often dwarfs the visible financial one. Teams that ignore this usually realize it too late.

DIY vs. Buy: The Tradeoffs

Once teams understand the scope, the decision usually boils down to: build your own validation process or buy a pre-certified toolchain.

Both paths can work, but the tradeoffs are very different.

The DIY Route

Pros:

• Complete control over validation scope and methods.
• Tailored exactly to your environment.
• No dependency on vendors.

Cons:

• Requires deep, specialized expertise.
• Resource-heavy, easily eating up months of engineering time.
• Needs to be repeated for every major toolchain update.

DIY might make sense if your toolchain is unusual or if your product lifecycle spans many years with minimal tool changes. But for most teams, it becomes a recurring drain.

The Buy Route

Pros:

• Validation already performed by the vendor.
• Delivered with certification kits, test evidence, and documentation that auditors recognize.
• Frees engineers to focus on product work.

Cons:

• Upfront license cost.
• You depend on vendor updates and release cadence.

This is precisely where IAR’s pre-certified toolchains fit in. Instead of spending 6-12 months validating compilers in-house, you get a certification kit that already includes test results, processes, and safety documentation aligned with ISO 26262, IEC 61508, and IEC 62304.

In other words, you get to skip the paperwork marathon and keep your engineers focused on building safety-critical products instead of compiler safety cases.

The ROI Perspective

On paper, licenses look expensive. But stack it against the hidden costs:

• Half a year of senior engineers’ salaries.
• QA staff for test campaigns.
• External consultants to prepare safety cases.
• Launch delays and lost revenue.

Nine times out of ten, buying isn’t just faster, it’s cheaper and safer.

It’s a Strategic Decision

Compliance is mandatory. The choice you have is in how you get there.

Choosing DIY or Buy isn’t a technical decision. It’s a strategic decision.

Some questions worth asking before you decide:

• How many safety projects will we run in the next 3–5 years?
• Do we want our best (and expensive) engineers writing features, or writing validation reports?
• What happens to our market window if a toolchain change delays us by a quarter?

Teams that treat compliance as a strategic decision (not just a box-check) end up shipping faster and staying competitive in markets where both speed and reliability are non-negotiable.

Pitfalls to Avoid if You Go DIY

If you do choose to validate in-house, avoid these traps:

• Skipping documentation early: If you don’t capture requirements and traceability from the start, you’ll end up backfilling paperwork under audit pressure.
• Ignoring toolchain updates: Even “minor” patches can invalidate your previous validation. Teams that ignore this often get burned in audits.
• Forgetting supply chain requirements: Auditors will ask for more than test logs. They’ll want lifecycle processes, risk analysis, and evidence that you’ve thought through every step.

DIY can work. But only if you commit to it as a long-haul project with the right resources.

Conclusion

Functional safety isn’t optional. But how you approach toolchain validation determines whether it becomes a black hole for engineering hours or a problem you’ve already solved.

Doing it yourself gives you control, but it eats up time and resources. Buying a pre-certified toolchain, like IAR’s safety-certified compilers, covering Arm, RISC‑V, STM8, and the Renesas RX, RL78, and RH850 families, all included in the IAR platform, takes that load off and lets you move faster with less risk.

The teams that succeed aren’t the ones treating compliance like a tax.

They’re the ones who make wise choices, cut down wasted effort, and keep their engineers focused on doing things that matter: building systems the world can trust.

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