Question on function-at-a-time and GC

[Richard Kenner]

    Wouldn't you want to do unit-at-a-time anyway, for optimisation?

Perhaps, but I'd want the choice of not doing so, if easy.

    If all you're doing is converting Ada trees to middle-end trees, then
    I wouldn't expect that process would generate much garbage.

Well, folding isn't cheap.

    If you use ggc_push_context, then you still get full collection
    between toplevel functions.  I don't know Ada well enough to know if
    it's common to have a single toplevel function with many nested
    subfunctions; if it's rare, you might find that you don't care about
    the inefficiencies of ggc_push_context.

The problem is that I don't know (or, more precisely don't want to have to
check) for every call to convert a tree whether or not there's a nested
subprogram someplace in there.  So these calls would basically have to be for
every tree node, which is very expensive.