[M3devel] struct pass and return, an additional mode?

[Jay K]

The frontend supports the following, Target.i3:


  results_on_left => when the front-end is passing structures the return
                     result is the left-most parameter.  Otherwise, it is
                     the right-most parameter.

  standard_structs =>
     TRUE => the front-end will take care of all structure passing:
       by VALUE parameters: callers pass the address of the structure
          and the callee copies it into a temporary.
       return results: the caller passes as the left-most or right-most
          parameter the address of the temporary that will hold the result
          and the callee copies the value there.
     FALSE =>
       by VALUE parameters: the back-end is responsible.
          (ie. M3CG.T.Pop_struct will be called)
       return results: the caller passes as the left-most or right-most
          parameter the address of the temporary that will hold the result
          and the callee copies the value there.  The start_call, call,
          and exit_proc methods are called with t=Struct.




I want an additional mode.
I want no extra parameter for struct return.
My backend could easily pass and return them by value and hide the details.


TYPE StructReturn = [None, Left, Right];
?


Too much is wrapped up in standard_structs -- pass and return could/should be separate.


TYPE StructPass = [Value, Pointer];
?


I grant that really supporting this in the frontend might be a bit of work,
and there might be little point, as the code is all rarely used.


Maybe I should work on improving something else, e.g. scopes or global variables/segments.


 - Jay
 		 	   		  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://m3lists.elegosoft.com/pipermail/m3devel/attachments/20130420/4c73c99d/attachment-0001.html>