Am 20.03.2006 um 14:39 schrieb holger krekel:
Hi Armin, Antonio,
On Mon, Mar 20, 2006 at 14:21 +0100, Armin Rigo wrote:
On Mon, Mar 20, 2006 at 10:52:42AM +0100, Antonio Cuni wrote:
I think it should be fairly simple to translate from the SSA form
to a
more "stack-friendly" form useful for stack-based machines; the
question
is: where to put such code?
Since it could be useful even for other backends, it would be
nice to
put it in some place where it can be shared from several
backends: one
option could be to write it as a backend optimization, but in
this case
we have to introduce new low level operations for stack
manipulation,
such as 'push', 'pop' or 'dup'.
Also useful for other back-ends would be a way to reconstruct some
kind
of "expression tree". For example, in Squeak, it is more
efficient to
generate a single complex expression instead of a lot of simple
expressions, because of the shuffling of the local variables that the
latter requires. The link with your suggestion is that these complex
expressions are also very stack-machine-friendly.
Interesting but isn't the IL code a bit too low level for that to
make full sense?
For generating Squeak bytecode (or Python bytecode for that
matter) it seems more obvious to me that generating (higher
level) complex expressions is worthwhile.
No, you would want complex expressions if you generate *source* code.
The *byte* code has to be one operation a time.
For Squeak there actually is a li'l compiler hack on my to-do list
introducing gotos ;-)
- Bert -
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