Re: Argument passing conventions and optimization

pradeep tumati <ptumati@yahoo.com> wrote:
>> I think you need to look for non-C compilers for this? If a compiler
>> encounters a C function, it can't be sure it is not exported via a
>> header somewhere, and those headers expect standard C calling
>> conventions.
>
>Most C compiler try following the standard ABI specifications of the
>target processor. Now, if a compiler optimizes the function call
>conventions, its not going to be sure if the callee is a library
>function. So, its better to follow the starndard conventions.


That applies to Unix and derived systems (including Microsoft ones),
where C is the definition language for the system call API. On a
system where it is not, such as IBM MVS, the converse applies. The C
calling conventions on that are legion, weird and VERY much unlike the
standard calling sequence in almost all cases!


>Does this case even apply to parameter passing in the case of static
>functions (in C)? Logically, we can perform optimization, but I am not
>sure what kind of side effects this causes... The same can be the case
>with functions calling other functions within the same C++ Namespace.


What's a static function in this context?


>There could be a scenario where this kind of optimization can be
>entrusted to the linker, but I guess its going to be a costly
>stuff. Any thoughts...?


It is. It is done. Many HPC vendors have such an option.


Regards,
Nick Maclaren.

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