Adding a front end to GCC

        I'm planning to add a new front end for BASIC to GCC but I've
    found some problems. From what I've seen GCC creates the RTL in
    the first pass, after processing each function.
        In BASIC (the structured dialects that exist nowadays) allow you
    to call a SUB/FUNCTION/DEF FN that are declared later in the file,
    for example :
          ...






          ....


          SUB sum (a%, b%)
              PRINT "The result is", a% + b%
          END SUB


        In order to do the type check at the CALL we need to know the type
    of the args of the SUB but it is declared later in the file. To solve
    this I think that the type checking can only be done in the second pass
    or using something like backpatching in order to be able to do it in the
    first pass.
        But none of these are what GCC expects, so I would like to know if
    someone has any idea about how GCC can handle a front end to a 2 pass
    language.


--
| Paulo Pinto, pjmlp@students.si.fct.unl.pt |
| http://students.fct.unl.pt/users/pjmlp |
[I'd write a two-pass compiler, one pass to get all the types, the second
pass to generate the RTL. Just slurp the whole source file into core,
it's the GCC way. -John]
--

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