[nhc-users] Re: porting nhc98 to plan9

[Fernan Bolando]

On Thu, Sep 10, 2009 at 3:57 PM, Malcolm Wallace
<malcolm.wallace at cs.york.ac.uk> wrote:
> Hi Fernan,
>
>> Aside from below code. I am also having problems compiling hc files with
>> #define CT_v249 ((void*)startLabel+464)
>
> By way of explanation, the idea of these symbols is that the bytecode
> sometimes needs to refer to an indexed position elsewhere in the bytecode.
>  If the indexed position needs to be visible externally (to this module), it
> is declared like
>
>>    unsigned F0_Prelude_46primLeave[] = {
>
> but in the cases where it need only be visible internal to the module (e.g.
> a constant table (CT) associated with a function), we use an address
> calculation instead:
>
>>    #define CT_v249     ((void*)startLabel+464)
>
> In both cases, it is important that the bytecode be continuous, that is, in
> a sequence like
>
>    , bytes2word('u','p','l','e')
>    };
>    unsigned PC_Prelude_4618[] = {
>      bytes2word('P','r','e','l')
>
> it is necessary that the bytes are really in the sequence
>
>    'u','p','l','e','P','r','e','l'
>
> The symbol PC-Prelude_4618 refers to the middle of this sequence - it should
> not start a new section of memory, separated from the previous section.
>
>
>> It appears that it is trying to pointer addition with a void*. This is
>> ok with gcc as a
>> "non-standard extension", but it will not work with plan9.
>>
>> So far I did this to make those section compile
>>
>> 1. changed userLabel define
>> --#define userLabel(fun) ((unsigned)fun)
>> ++#define userLabel(fun) ((unsigned*)fun)
>>
>> 2. removed void* pointer addition by writing a script
>> from #define CT_v249    ((void*)startLabel+464)
>> to #define CT_v249      ((unsigned char*)startLabel+464)
>
> OK, that seems like a reasonable change - it should preserve the invariants
> I described above.
>
> If you manage to get nhc98 bootstrapped on plan9, do please send your
> changes to me, so that I can incorporate them into the main nhc98 tree -
> then everyone else can benefit too.
>

Hi Malcolm

Thank you for your explanation of the bytecode. I really havn't
understand the nhc98comp operation yet. I am basically just running
the c files through the plan9 compiler and fix what ever issues come
up.

I am still doing a lot of guessing here, but I a few more questions.
1. The hc files are generated by nhc98comp? I will still need to
modify nhc98comp to always produce the unsigned char*?

2. I am also bypassing nhc98 script during the prelude build. I am
created a separate script to compile prelude under plan9. The script
just loads the hc files into the C compiler.

3. I am still guessing here, but If item 2 is an ok approach is it
possible to simply compile src/runtime/Runtime.a and use the .o files
from a unix build?

thanks
fernan
-- 
http://www.fernski.com