abi

abi

[André Albergaria Coelho]

If we can select the ABi for our program (using gcc), why is there a 
need for ABI stability?!

why not put it on a define


#define abi v3

int main() {

}


Each user would just have to compile the code, to follow the abi...no 
need to worry changing it


thanks


andre

Re: abi

[Paul Koning]

Because implementing an ABI, or dealing with an incompatibnle change, is hard work.  Also, ABI stability means that old binaries work.  So ABI stability isn't so much a requirement for the compiler as it is a requirement for any sane operating system.  An OS that changes ABI without an extremely good reason is an OS that doesn't care about compatibility, which means it doesn't care about its customers.

The MIPS examples I pointed to are a good illustration of this.  The original ("O32") ABI is for MIPS with 32 bit registers and 32 bit addressing.  N32 and N64 were introduced by SGI to support 64 bit registers, and (for N64) 64 bit pointers.  That's a very compelling benefit.  64 bbit addressing is obvious, and the performance benefit from using 64 bit registers on machines that have them is very large.  So there, the quite large cost of doing this was totally justified.

	paul

> On Jul 9, 2023, at 4:55 PM, André Albergaria Coelho via Gcc <gcc@gcc.gnu.org> wrote:
> 
> If we can select the ABi for our program (using gcc), why is there a need for ABI stability?!
> 
> why not put it on a define
> 
> 
> #define abi v3
> 
> int main() {
> 
> }
> 
> 
> Each user would just have to compile the code, to follow the abi...no need to worry changing it
> 
> 
> thanks
> 
> 
> andre
> 

Re: abi

[André Albergaria Coelho]

Can we debate in this mailing list?  thanks


On 7/9/23 22:04, Paul Koning wrote:
> Because implementing an ABI, or dealing with an incompatibnle change, is hard work.


  you could just use one ABI..(that's what you have)..you can use other 
, only at a cost of specifying an ABI version

the abi is text though..so you only have to write a text file....


>   Also, ABI stability means that old binaries work

when you mean binaries, do you mean ELF files? executable files?


> .  So ABI stability isn't so much a requirement for the compiler as it is a requirement for any sane operating system.

what does  a calling convention, has to do with syscalls?! and syscalls, 
and calling conventions, have to do with size and layouts?

used wikipedia definition 
..https://en.wikipedia.org/wiki/Application_binary_interface


how can the OS, have a binary interface?!!


for example:

prtinf("abc"),

asm  (say mov $123,%eax)

  binary instruction is 010110101 (for example)...how can the operating 
system know what interface to use?!


say i have 101010110101  1010101010101 , how does the O.S  works on 
binary files?! say how is the syscall used (at binary level)..it had to 
be compiled / assembled


int main() {

     write(123,&test_ptr,,count);

}

say write syscall is  "101010101001" in binary  ,so how does the O.S 
interfaces this ? does the O.S. separate binary numbers?!?


unless you meant ELF as "binary program"





An OS that changes ABI without an extremely good reason is an OS that 
doesn't care about compatibility, which means it doesn't care about its 
customers.




> The MIPS examples I pointed to are a good illustration of this.  The original ("O32") ABI is for MIPS with 32 bit registers and 32 bit addressing.  N32 and N64 were introduced by SGI to support 64 bit registers, and (for N64) 64 bit pointers.  That's a very compelling benefit.  64 bbit addressing is obvious, and the performance benefit from using 64 bit registers on machines that have them is very large.  So there, the quite large cost of doing this was totally justified.

The benefit would be for the user...code like it wants (for example, 
return value in %ecx)..which is the ultimate reason to use compilers

and also, the benefit would be to use every ABI possible (choosing the best)


> 	paul
>
>> On Jul 9, 2023, at 4:55 PM, André Albergaria Coelho via Gcc <gcc@gcc.gnu.org> wrote:
>>
>> If we can select the ABi for our program (using gcc), why is there a need for ABI stability?!
>>
>> why not put it on a define
>>
>>
>> #define abi v3
>>
>> int main() {
>>
>> }
>>
>>
>> Each user would just have to compile the code, to follow the abi...no need to worry changing it
>>
>>
>> thanks
>>
>>
>> andre
>>
> andre

Re: abi

[Jonathan Wakely]

[-- Attachment #1: Type: text/plain, Size: 334 bytes --]

On Thu, 6 Jul 2023, 22:20 André Albergaria Coelho via Gcc, <gcc@gcc.gnu.org>
wrote:

> Could gcc have an option to specify ABI?
>
> say
>
>
> gcc something.c -g -abi 1 -o something
>

Sure, it could do, but what would it do? What would "-abi 1" mean? Which
ABI would it relate to?

What are you actually asking about?

Re: abi

[Paul Koning]

It does, for machine architectures that have multiple ABIs.  MIPS is an example where GCC has supported this for at least 20 years.

	paul

> On Jul 6, 2023, at 5:19 PM, André Albergaria Coelho via Gcc <gcc@gcc.gnu.org> wrote:
> 
> Could gcc have an option to specify ABI?
> 
> say
> 
> 
> gcc something.c -g -abi 1 -o something
> 
> 
> thanks
> 
> 
> andre
> 

abi

[André Albergaria Coelho]

Could gcc have an option to specify ABI?

say


gcc something.c -g -abi 1 -o something


thanks


andre

abi

[Peter Johnston]

Dear All,

Using egcs1.1.1 on Irix5.3, is there any reason why the -mabi
(eg -mabi=n32) options should not work?

Cheers

Peter



Dr Peter Johnston
DISAT
Universita' degli Studi di Milano
Via Emanueli, 15
Milano 20126
Italy
peter@alpha.disat.unimi.it
Tel: +39-02-64474415
Fax: +39-02-64474400
IMPORTANT: The '0' is not a mistake!

abi

[Peter Johnston]

Dear All,

Using egcs1.1.1 on Irix5.3, is there any reason why the -mabi
(eg -mabi=n32) options should not work?

Cheers

Peter



Dr Peter Johnston
DISAT
Universita' degli Studi di Milano
Via Emanueli, 15
Milano 20126
Italy
peter@alpha.disat.unimi.it
Tel: +39-02-64474415
Fax: +39-02-64474400
IMPORTANT: The '0' is not a mistake!