binary compatibility ABI (was: Re: [boehm-gc] Import 6.3 alpha 1)

Wed Aug 13 17:37:00 GMT 2003

On Sat, 2 Aug 2003, Bryce McKinlay wrote:
> Sounds like -fno-assume-compiled and the binary compatibility ABI are
> two different means to the same end.

I think so, too. Both -fno-assume-compiled and -findirect-dispatch are
incomplete solutions towards a general implementation of binary
compatibility. Perhaps both should become part of the new ABI,
and the old flags can then be deprecated.
> I'm confident that, if the
> compiler is made smart enough, the performance impact of the new ABI
> would be negligible enough, and other benefits like ease-of-use, faster
> link and load times, and smaller binaries significant enough, to make
> it the default ABI.

One of my sore points is the performance gap between static and
position-independent code with the current gcj compiler. For example:
reading a static field requires one memory load without -fPIC, but two
loads with -fPIC (to obtain the memory address from the GOT offset).
It'd be great if the new ABI can somehow improve the performance of shared
code.
Jeff