Re: [MirageOS-devel] Camlp4 Stack_overflow

[Andrà NÃss <andre.naess@xxxxxxxxx>]

It looked like the snippet of code I included in the first post,
except with 25,000 rows.

The _tags file solved it though. I excluded the file like this:
<Pb.*>:-syntax(camlp4o)

With this in place I successfully compiled 500K entries in 1m30s
yielding a 33MB .xen file.

I can certainly post an issue on the camlp4 github site and attach an
example file if you think this should reasonably work. I wouldn't
think this represent a common usecase ;)

On Thu, May 8, 2014 at 10:33 AM, Thomas Gazagnaire
<thomas@xxxxxxxxxxxxxx> wrote:
> do you have an example of what the generated source file looks like ?
>
> Would be interesting to report the bug upstream: 
> https://github.com/ocaml/camlp4/issues
>
> Thomas
>
> On 7 May 2014, at 23:38, Anil Madhavapeddy <anil@xxxxxxxxxx> wrote:
>
>> To address the camlp4 problem, you can use the _tags file to mark just
>> the one source file as not passing through camlp4 (via a '-' somewhere
>> to remove the tag -- will need to look up the details in the manual).
>>
>> The easiest way to solve your problem would be just to have a crunched
>> file containing the information in CSV or S-expression format, and then
>> reading from it at application startup time to initialize your array.
>>
>> The 'crunch' mode would compile all this into a standalone kernel, or
>> in Unix mode would be a filesystem passthrough for easier development.
>> Any reason you want it to be a 'hand written' OCaml file?
>>
>> -anil
>>
>> On 7 May 2014, at 14:06, Andrà NÃss <andre.naess@xxxxxxxxx> wrote:
>>
>>> I've rewritten the generated code so that it creates an array and then
>>> assigns to indexes of the array, batching the assignments using
>>> multiple let () =
>>>
>>> Compilation speed is a problem, and it still falls over at 50K entries.
>>>
>>> I suppose I could somehow write the data to an image and read it back
>>> in at application startup, but I think I actually like my current
>>> approach. All of the work is done at compilation time. The rows are
>>> written in sorted order so a simple binary search can be used. The
>>> resulting application is entirely single-purposed.
>>>
>>> Any ideas for other ways to do this? Bypass the compiler and "compile"
>>> the data myself? Does there exist tools to do something like that?
>>>
>>> On Wed, May 7, 2014 at 1:40 PM, Andrà NÃss <andre.naess@xxxxxxxxx> wrote:
>>>> Hi
>>>>
>>>> I'm trying something that might be a bit silly but it's just intended
>>>> as an internal demo of Mirage to my team. I'm writing a tiny HTTP
>>>> based application whose only purpose is to allow you to search a phone
>>>> book.
>>>>
>>>> I've based my approach on the approach you've used for static websites
>>>> using crunch where you compile the web pages into the executable. In
>>>> my case that means I take the list of name and number pairs and stuff
>>>> them into an array. So part of my config.ml file emits a single Pb.ml
>>>> file which contains an array declaration like this:
>>>>
>>>> let db = [|("Aaron Jaksic",1571268);
>>>> ("Aaron Mcdivitt",1454629);
>>>> ("Aaron Reuben",1765247);
>>>> ("Aaron Sardinha",1224806);
>>>> ("Abbey Gowens",1267083);
>>>> ("Abbey Hathcox",1309490);
>>>> ...
>>>>
>>>> As the title say I'm running into problems compiling this when I
>>>> create a large phone book, the error being:
>>>>
>>>> Camlp4: Uncaught exception: Stack_overflow
>>>>
>>>> This happens with 25K entries, it works with 10K entries.
>>>>
>>>> Is there some way I can prevent Camlp4 from being run on the Pb.ml
>>>> file? Or will I just have to generate a file that builds the array at
>>>> runtime somehow?
>>>>
>>>> AndrÃ
>>>
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>>
>>
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