llvm dev - Sep 2008 - [LLVMdev] Newbie question on front-end and code compaction

Hi!

I'm still a newbie to LLVM, so I'm looking for guidance that will tell
me
the right docs to read.

I'm interested in working on 2 different things.  I'm interested on
adding a
new front end for a functional language such as Lisp.  I'm also interested
in helping out with compaction(making code with a small footprint).  What
are the right docs for me to start reading and reviewing?

tia,
Bernardo
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On Thu, Sep 4, 2008 at 8:03 PM, Bernardo Elayda <belayda at gmail.com>
wrote:
> Hi!
>
> I'm still a newbie to LLVM, so I'm looking for guidance that will
tell me
> the right docs to read.
>
> I'm interested in working on 2 different things.  I'm interested on
adding a
> new front end for a functional language such as Lisp.  I'm also
interested
> in helping out with compaction(making code with a small footprint).  What
> are the right docs for me to start reading and reviewing?
I'd start with the kaleidoscope tutorials, they taught me a lot about llvm:

http://llvm.org/docs/tutorial/

On Sep 4, 2008, at 8:03 PM, Bernardo Elayda wrote:
> I'm also interested in helping out with compaction(making code with  
> a small footprint).
People pointed out recently on the list that -Os doesn't work so  
well.  See the email from regehr at cs.utah.edu on Aug 20 on llvmdev.   
You should be able to work with him to get testcases, from there you  
just grind through them and find why they are bigger and reduce them.   
Failing that, just compile up any software and compare.  Should be  
lots of low hanging fruit.

On Sep 5, 2008, at 10:06 AMPDT, Mike Stump wrote:
> On Sep 4, 2008, at 8:03 PM, Bernardo Elayda wrote:
>> I'm also interested in helping out with compaction(making code with
>> a small footprint).
>
> People pointed out recently on the list that -Os doesn't work so
> well.  See the email from regehr at cs.utah.edu on Aug 20 on llvmdev.
> You should be able to work with him to get testcases, from there you
> just grind through them and find why they are bigger and reduce them.
> Failing that, just compile up any software and compare.  Should be
> lots of low hanging fruit.
Thread starts here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2008-August/016600.html
The last message points out inlining and unrolling heuristics as low- 
hanging fruit, and I agree.
But there is a lot more beyond that, particular instruction selection  
on x86.