[Vm-dev] gcc -Wall -pedantic (was: sweep failed to find exact
end of memory)
andreas.raab at gmx.de
Wed Apr 25 21:32:08 UTC 2007
David T. Lewis wrote:
> On Wed, Apr 25, 2007 at 09:48:55AM -0700, Andreas Raab wrote:
>> Looking over your changes I see two consistent patterns: One is to
>> change all oops from sqInt to usqInt and the other one is to use the
>> "special" unsigned comparison for pointers. Is my interpretation
>> essentially correct?
> Yes, exactly so.
Thanks (just trying to make sure that I'm getting the gist of the changes).
> All oop arithmetic (e.g. adding to an oop) works fine regardless
> of signed or unsigned declarations. As an aside, whomever came up
> with the idea of twos compliment arithmetic deserves great credit
> for Doing Things Right In The First Place.
Indeed. It's pretty amazing to see how this stuff works regardless ;-)
> I thought that adding the four "special" comparison methods was
> somewhat less ugly than putting the casts into each impacted method
> throughout ObjectMemory and Interpreter. It also allowed me to add
> some method comments to explain why it was being done.
Yes, I agree. I far prefer it to sprinkling the casts all over the
places; it is a reminder about the fact that one needs to use those methods.
>> I'm open for any suggestions on how to improve this situation.
> Two ideas:
> 1) If we could declare the return type of a method and still generate
> inlined code, then it would probably be possible to eliminate most
> of the type casting, and therefore also eliminate the four "special"
> comparison methods that implement the type casting.
Yes, that's a good idea and should be entirely doable. Really, all we
need is a conversion of #returnType: into a cCoerce: in the inliner.
Should be quite doable.
More information about the Vm-dev