no-pointer areas

[Thomas Kuehne]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Craig Black schrieb am 2006-10-23:
>
> Overall a very, very good idea.
> However, why does the bytes allocated per element have to be the 
> qualification?
> This seems a bit convoluted to me. Why not just add a parameter with a 
> default value?
>
> void *malloc(size_t size, int hasPtr = 1);

That's what malloc_no_ptr was meant for, using a default parameter
might be more useful though. Using int seems strange, how about:

void *malloc(size_t size, bool hasPtr = true);

Bytes per element doesn't require any cooperation by the compiler.
Naturally the compiler could take advantage later on and use the
no-pointer functions.

Thomas

> "Thomas Kuehne" <thomas-dloop at kuehne.cn> wrote in message 
>> With all that Phobos talk going on ... here is a small task:
>>
>> Implement GC areas that are guaranteed to contain no pointers
>> and are subsequently not searched for pointers during GC-collections.
>>
>> Basic Idea:
>>
>> void *malloc(size_t size);
>> void *calloc(size_t nmemb, size_t size);
>>
>> If less than sizeof(size_t) bytes are allocated per element, the
>> allocated memory is guaranteed to contain no pointers.
>>
>> There are three implementation levels:
>>
>> 1) Basic (dmd/src/phobos/internal/gc/gcx.d)
>>
>> Implement the basic idea(malloc, calloc, realloc, ...) and provide
>> the functions malloc_no_ptr, calloc_no_ptr, realloc_no_ptr.
>>
>> 2) Complete (dmd/src/phobos/internal/gc/gc.d)
>>
>> Update the code to take advantage of gcx.d's *_no_ptr.
>>
>> 3) Extended (compiler and dmd/src/phobos/internal/gc/gc.d)
>>
>> By adding compiler support, elements with sizes larger than or
>> equal to sizeof(size_t) that contain no pointers (e.g. the data
>> portion of float arrays and some structs)can use the no-ptr pools.
>>
>> As a result, the GC for applications using lots of data arrays should
>> be noticeably faster while other applications shouldn't experience any
>> measurable speed decreases.
>>
>> Thomas

-----BEGIN PGP SIGNATURE-----

iD8DBQFFPa/rLK5blCcjpWoRApScAJ9gQnpjFFwr1glgOjngylTPipjBxgCdGm4K
9UXiWoNxIWEvdB+lpoYFfLA=
=Z5M4
-----END PGP SIGNATURE-----