[HN Gopher] How Compiler Explorer Works in 2025
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How Compiler Explorer Works in 2025
Author : vitaut
Score : 205 points
Date : 2025-06-04 17:32 UTC (5 days ago)
(HTM) web link (xania.org)
(TXT) w3m dump (xania.org)
| unconed wrote:
| Putting AI disclaimers at the end of your post seems like the
| wrong way to do it. If you feel the need to put a disclaimer, put
| it at the top. Otherwise, what's the point?
| YetAnotherNick wrote:
| AI disclaimer is both in the top and bottom. First box
| contains:
|
| > Written with LLM assistance. Details at end.
| unconed wrote:
| Yep I totally didn't notice it because it's off to the side
| and looks like some kind of promo box.
| thesnide wrote:
| i would argue that it might actually be a kind of promo box
| :-)
| arkj wrote:
| Will anything be ever written in future without a little help
| from llm?
| windward wrote:
| They're not even really disclaimers. There's no legal
| liability. It's just disclosure.
| quaintdev wrote:
| Is it just me or something is wrong with HN
| https://ibb.co/0RwqjZvP
| arkj wrote:
| An interesting glitch. A few more refreshes and got the site
| unavailable message. It's fixed now.
| arkj wrote:
| Maybe it's a client side error but I see three links of this post
| on the homepage.
| psnehanshu wrote:
| The tool is called Compiler Explorer, but is hosted at
| godbolt.org. There's also compliler-explorer.com, which is the
| same thing. Why not retire the first domain? Just redirect to the
| namesake domain to prevent link rot.
| krackers wrote:
| Because most people colloquially know it as "Godbolt".
| MeetingsBrowser wrote:
| Most people I know, including myself, refer to it as godbolt
| and not compiler explorer.
|
| I didn't know it was hosted anywhere other than godbolt.org
| 0xTJ wrote:
| When I want to visit Compiler Explorer, I start typing godbolt,
| then his Enter when the browser brings up the correct item from
| my History. "compiler-explorer.com" is also much longer (if you
| want to type out the whole things).
| jevndev wrote:
| Funny enough, he has talked about this exact problem on his
| podcast "Two's complement"; Specifically the episode "The
| future of compiler explorer". Commenters below are correct that
| it's just about how heavily associated his name is with the
| tool. I just figured I'd also drop this source here because he
| has a lot of interesting things to say about his involvement
| with the project
| 57473m3n7Fur7h3 wrote:
| For anyone else wanting to listen to the episode, this site
| worked well for me:
|
| https://podtail.com/en/podcast/two-s-complement/the-
| future-o...
|
| It does have ads, but they were not too intrusive. Scroll
| down if there's an ad on first click and there's a play
| button that plays the episode.
|
| For me the ads it showed were only text and images, not audio
| interrupting ads.
|
| You can also listen to it on YouTube:
|
| https://www.youtube.com/watch?v=2QXo5c7cUKQ
|
| But since it's audio only, I preferred listening to it via
| the aforementioned podcast website.
| gpderetta wrote:
| The godbolt name is so iconic that at $WORK our locally hosted
| instance of compiler explorer is under the go/godbolt shortcut.
| porridgeraisin wrote:
| The go/godbolt shortcut form tells me that WORK=google
|
| Is it right?
| gpderetta wrote:
| I had the go/ shortcut at at least two different jobs.
| Neither was G. But it is possible that xooglers set it up.
| wild_pointer wrote:
| How about compiling client-side with wasm, fully or partially?
| Feasible? Was it considered?
| petabyt wrote:
| Some of the compilers they use (msvc) are not open source and
| are not allowed to run in wasm. And porting entire compiler
| toolchains to wasm would be a gargantuan task.
| charcircuit wrote:
| WASM has x86 emulators.
| tempay wrote:
| It would be a lot of data to download and would likely be
| uncomfortably slow for many cases.
|
| Also, as is mentioned in the article in a few places, the
| website is optimised for low effort rather than low cost.
| jenadine wrote:
| That would imply compiling each compiler to wasm, which might
| not be supported. Plus challenges like making a virtual file
| system to get the header files and other files needed for the
| compilation.
|
| Edit: also, you couldn't execute the resulting binary
| galkk wrote:
| tl;dr: * Right now, Compiler Explorer costs
| around $3000 a month (including AWS, monitoring, Sentry for
| errors, Grafana, and other expenses). * nsjail for
| security/isolation * 3.9 terabytes of compilers,
| libraries, and tools * Up to 30+ EC2 instances (EC2
| instances are virtual machines) * 4,724 compiler versions
| * 1,982,662 short links saved (and as of recently, ~14k ex-goo.gl
| links) * 1.8 million compilations per week
|
| If my napkin math is correct, it's around 3 compilations/sec. and
| their cost is 0.0004 cents per compilation. Fascinating. If
| anyone asked me about ballpark estimate of compiler explorer
| cost, I'd be wrong at least at magnitude. Like - they must be
| heavy cpu/io/network bound, and this is like the worst scenario
| for cloud use.
|
| This and lichess
| (https://news.ycombinator.com/item?id=41922928#41928953) shows
| that you really can handle very serious loads for quite cheap.
| dieortin wrote:
| > $3,00015
|
| That's a very weird place to put a comma. I have no idea what
| number this is representing (since I doubt it's $3 a month)
| detaro wrote:
| the 15 is a copy-paste error (footnote)
| sapiogram wrote:
| Thank you, the comment has value now.
| maccard wrote:
| I'd love to see a breakdown of their ec2 costs vs everything
| else. I'd expect that if they really wanted to a single bare
| metal machine would probably save them a decent chunk of money.
|
| But $3k/mo is surprisingly lean!
| mattgodbolt wrote:
| I'll do a follow-up post sometime on where the money goes.
| tomcam wrote:
| > 8. Your browser renders the assembly, and you go "ooh, how
| clever is this compiler!"
|
| Incorrect. I go "ooh, the appropriately named Mr. Godbolt is a
| fucking beast!"
| mattgodbolt wrote:
| So sorry to disappoint you, but I'm really not :D
| gpderetta wrote:
| > I really don't know how many developers use Compiler Explorer:
| we purposefully don't have the kind of tracking that could tell
| us. But, it's at least in the thousands I think
|
| I think this a large underestimate :D
| knowitnone wrote:
| Why do you say that? I've bookmarked the site but I've never
| used it. If my code compiles, I'm good. Not many people dig
| into the assembly to find that extra 1% performance boost. I'm
| not saying this tool is not useful because it is but how often
| do you use it?
| JavierFlores09 wrote:
| I seldom use it myself, but I frequently see people sharing
| compiler explorer snippets to compare generated assembly on
| discord conversations about LLVM in just about any native
| language discord (but mainly the Rust official one), which
| may sound like a rare occasion, but it happens more often
| than you'd think. My impression is that it is definitely in
| the thousands, but it being a service that I've only seen
| used for quick comparisons rather than in-depth analysis, I
| can't tell whether it is much more than that
| gpderetta wrote:
| While it might have been started to inspect the assembly,
| these days I mostly see it getting used to share compilable
| code and test it against multiple compilers.
|
| Sometimes is just a quick way to test minimalist code snipets
| pfdietz wrote:
| I wonder how many compiler crashes they experience. That's a lot
| of test cases.
| cerisier wrote:
| For the author: are there any plans to make the compilers builds
| available ? Prebuilt gccs are a rare and valuable spice !
| mattgodbolt wrote:
| They are already free and available. Check out our "infra" repo
| and the ce_install tool and/or just hack the S3 URLs
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